feat: Rebrand Polkadot/Substrate references to PezkuwiChain

This commit systematically rebrands various references from Parity Technologies'
Polkadot/Substrate ecosystem to PezkuwiChain within the kurdistan-sdk.

Key changes include:
- Updated external repository URLs (zombienet-sdk, parity-db, parity-scale-codec, wasm-instrument) to point to pezkuwichain forks.
- Modified internal documentation and code comments to reflect PezkuwiChain naming and structure.
- Replaced direct references to  with  or specific paths within the  for XCM, Pezkuwi, and other modules.
- Cleaned up deprecated  issue and PR references in various  and  files, particularly in  and  modules.
- Adjusted image and logo URLs in documentation to point to PezkuwiChain assets.
- Removed or rephrased comments related to external Polkadot/Substrate PRs and issues.

This is a significant step towards fully customizing the SDK for the PezkuwiChain ecosystem.

bizinikiwi/client/network/Cargo.toml

@@ -0,0 +1,124 @@
+[package]
+description = "Bizinikiwi network protocol"
+name = "pezsc-network"
+version = "0.34.0"
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+authors.workspace = true
+edition.workspace = true
+homepage.workspace = true
+repository.workspace = true
+documentation = "https://docs.rs/pezsc-network"
+readme = "README.md"
+
+[lints]
+workspace = true
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[[bench]]
+name = "notifications_protocol"
+harness = false
+
+[[bench]]
+name = "request_response_protocol"
+harness = false
+
+[dependencies]
+array-bytes = { workspace = true, default-features = true }
+async-channel = { workspace = true }
+async-trait = { workspace = true }
+asynchronous-codec = { workspace = true }
+bytes = { workspace = true, default-features = true }
+cid = { workspace = true }
+codec = { features = ["derive"], workspace = true, default-features = true }
+either = { workspace = true, default-features = true }
+fnv = { workspace = true }
+futures = { workspace = true }
+futures-timer = { workspace = true }
+ip_network = { workspace = true }
+libp2p = { features = [
+	"dns",
+	"identify",
+	"kad",
+	"macros",
+	"mdns",
+	"noise",
+	"ping",
+	"request-response",
+	"tcp",
+	"tokio",
+	"websocket",
+	"yamux",
+], workspace = true }
+linked_hash_set = { workspace = true }
+litep2p = { workspace = true }
+log = { workspace = true, default-features = true }
+mockall = { workspace = true }
+parking_lot = { workspace = true, default-features = true }
+partial_sort = { workspace = true }
+pin-project = { workspace = true }
+prometheus-endpoint = { workspace = true, default-features = true }
+prost = { workspace = true }
+rand = { workspace = true, default-features = true }
+pezsc-client-api = { workspace = true, default-features = true }
+pezsc-network-common = { workspace = true, default-features = true }
+pezsc-network-types = { workspace = true, default-features = true }
+pezsc-utils = { workspace = true, default-features = true }
+schnellru = { workspace = true }
+serde = { features = ["derive"], workspace = true, default-features = true }
+serde_json = { workspace = true, default-features = true }
+smallvec = { workspace = true, default-features = true }
+pezsp-arithmetic = { workspace = true, default-features = true }
+pezsp-blockchain = { workspace = true, default-features = true }
+pezsp-core = { workspace = true, default-features = true }
+pezsp-runtime = { workspace = true, default-features = true }
+thiserror = { workspace = true }
+tokio = { features = [
+	"macros",
+	"sync",
+], workspace = true, default-features = true }
+tokio-stream = { workspace = true }
+unsigned-varint = { features = [
+	"asynchronous_codec",
+	"futures",
+], workspace = true }
+void = { workspace = true }
+wasm-timer = { workspace = true }
+zeroize = { workspace = true, default-features = true }
+
+[dev-dependencies]
+assert_matches = { workspace = true }
+multistream-select = { workspace = true }
+pezsc-block-builder = { workspace = true, default-features = true }
+pezsp-consensus = { workspace = true, default-features = true }
+pezsp-crypto-hashing = { workspace = true, default-features = true }
+pezsp-tracing = { workspace = true, default-features = true }
+bizinikiwi-test-runtime = { workspace = true }
+bizinikiwi-test-runtime-client = { workspace = true }
+tempfile = { workspace = true }
+tokio = { features = [
+	"macros",
+	"rt-multi-thread",
+], workspace = true, default-features = true }
+tokio-util = { features = ["compat"], workspace = true }
+
+criterion = { workspace = true, default-features = true, features = [
+	"async_tokio",
+] }
+
+[build-dependencies]
+prost-build = { workspace = true }
+
+[features]
+default = []
+runtime-benchmarks = [
+	"pezsc-block-builder/runtime-benchmarks",
+	"pezsc-client-api/runtime-benchmarks",
+	"pezsc-network-common/runtime-benchmarks",
+	"pezsp-blockchain/runtime-benchmarks",
+	"pezsp-consensus/runtime-benchmarks",
+	"pezsp-runtime/runtime-benchmarks",
+	"bizinikiwi-test-runtime-client/runtime-benchmarks",
+	"bizinikiwi-test-runtime/runtime-benchmarks",
+]

bizinikiwi/client/network/README.md

@@ -0,0 +1,287 @@
+Bizinikiwi-specific P2P networking.
+
+**Important**: This crate is unstable and the API and usage may change.
+
+# Node identities and addresses
+
+In a decentralized network, each node possesses a network private key and a network public key.
+In Bizinikiwi, the keys are based on the ed25519 curve.
+
+From a node's public key, we can derive its *identity*. In Bizinikiwi and libp2p, a node's
+identity is represented with the [`PeerId`] struct. All network communications between nodes on
+the network use encryption derived from both sides's keys, which means that **identities cannot
+be faked**.
+
+A node's identity uniquely identifies a machine on the network. If you start two or more
+clients using the same network key, large interferences will happen.
+
+# Bizinikiwi's network protocol
+
+Bizinikiwi's networking protocol is based upon libp2p. It is at the moment not possible and not
+planned to permit using something else than the libp2p network stack and the rust-libp2p
+library. However the libp2p framework is very flexible and the rust-libp2p library could be
+extended to support a wider range of protocols than what is offered by libp2p.
+
+## Discovery mechanisms
+
+In order for our node to join a peer-to-peer network, it has to know a list of nodes that are
+part of said network. This includes nodes identities and their address (how to reach them).
+Building such a list is called the **discovery** mechanism. There are three mechanisms that
+Bizinikiwi uses:
+
+- Bootstrap nodes. These are hard-coded node identities and addresses passed alongside with
+the network configuration.
+- mDNS. We perform a UDP broadcast on the local network. Nodes that listen may respond with
+their identity. More info [here](https://github.com/libp2p/specs/blob/master/discovery/mdns.md).
+mDNS can be disabled in the network configuration.
+- Kademlia random walk. Once connected, we perform random Kademlia `FIND_NODE` requests on the
+configured Kademlia DHTs (one per configured chain protocol) in order for nodes to propagate to
+us their view of the network. More information about Kademlia can be found [on
+Wikipedia](https://en.wikipedia.org/wiki/Kademlia).
+
+## Connection establishment
+
+When node Alice knows node Bob's identity and address, it can establish a connection with Bob.
+All connections must always use encryption and multiplexing. While some node addresses (eg.
+addresses using `/quic`) already imply which encryption and/or multiplexing to use, for others
+the **multistream-select** protocol is used in order to negotiate an encryption layer and/or a
+multiplexing layer.
+
+The connection establishment mechanism is called the **transport**.
+
+As of the writing of this documentation, the following base-layer protocols are supported by
+Bizinikiwi:
+
+- TCP/IP for addresses of the form `/ip4/1.2.3.4/tcp/5`. Once the TCP connection is open, an
+encryption and a multiplexing layer are negotiated on top.
+- WebSockets for addresses of the form `/ip4/1.2.3.4/tcp/5/ws`. A TCP/IP connection is open and
+the WebSockets protocol is negotiated on top. Communications then happen inside WebSockets data
+frames. Encryption and multiplexing are additionally negotiated again inside this channel.
+- DNS for addresses of the form `/dns/example.com/tcp/5` or `/dns/example.com/tcp/5/ws`. A
+node's address can contain a domain name.
+- (All of the above using IPv6 instead of IPv4.)
+
+On top of the base-layer protocol, the [Noise](https://noiseprotocol.org/) protocol is
+negotiated and applied. The exact handshake protocol is experimental and is subject to change.
+
+The following multiplexing protocols are supported:
+
+- [Yamux](https://github.com/hashicorp/yamux/blob/master/spec.md).
+
+## Substreams
+
+Once a connection has been established and uses multiplexing, substreams can be opened. When
+a substream is open, the **multistream-select** protocol is used to negotiate which protocol
+to use on that given substream.
+
+Protocols that are specific to a certain chain have a `<protocol-id>` in their name. This
+"protocol ID" is defined in the chain specifications. For example, the protocol ID of PezkuwiChain
+is "hez". In the protocol names below, `<protocol-id>` must be replaced with the corresponding
+protocol ID.
+
+> **Note**: It is possible for the same connection to be used for multiple chains. For example,
+> one can use both the `/hez/sync/2` and `/sub/sync/2` protocols on the same
+> connection, provided that the remote supports them.
+
+Bizinikiwi uses the following standard libp2p protocols:
+
+- **`/ipfs/ping/1.0.0`**. We periodically open an ephemeral substream in order to ping the
+remote and check whether the connection is still alive. Failure for the remote to reply leads
+to a disconnection.
+- **[`/ipfs/id/1.0.0`](https://github.com/libp2p/specs/tree/master/identify)**. We
+periodically open an ephemeral substream in order to ask information from the remote.
+- **[`/<protocol_id>/kad`](https://github.com/libp2p/specs/pull/108)**. We periodically open
+ephemeral substreams for Kademlia random walk queries. Each Kademlia query is done in a
+separate substream.
+
+Additionally, Bizinikiwi uses the following non-libp2p-standard protocols:
+
+- **`/bizinikiwi/<protocol-id>/<version>`** (where `<protocol-id>` must be replaced with the
+protocol ID of the targeted chain, and `<version>` is a number between 2 and 6). For each
+connection we optionally keep an additional substream for all Bizinikiwi-based communications alive.
+This protocol is considered legacy, and is progressively being replaced with alternatives.
+This is designated as "The legacy Bizinikiwi substream" in this documentation. See below for
+more details.
+- **`/<protocol-id>/sync/2`** is a request-response protocol (see below) that lets one perform
+requests for information about blocks. Each request is the encoding of a `BlockRequest` and
+each response is the encoding of a `BlockResponse`, as defined in the `api.v1.proto` file in
+this source tree.
+- **`/<protocol-id>/light/2`** is a request-response protocol (see below) that lets one perform
+light-client-related requests for information about the state. Each request is the encoding of
+a `light::Request` and each response is the encoding of a `light::Response`, as defined in the
+`light.v1.proto` file in this source tree.
+- **`/<protocol-id>/transactions/1`** is a notifications protocol (see below) where
+transactions are pushed to other nodes. The handshake is empty on both sides. The message
+format is a SCALE-encoded list of transactions, where each transaction is an opaque list of
+bytes.
+- **`/<protocol-id>/block-announces/1`** is a notifications protocol (see below) where
+block announces are pushed to other nodes. The handshake is empty on both sides. The message
+format is a SCALE-encoded tuple containing a block header followed with an opaque list of
+bytes containing some data associated with this block announcement, e.g. a candidate message.
+- Notifications protocols that are registered using `NetworkConfiguration::notifications_protocols`.
+For example: `/paritytech/grandpa/1`. See below for more information.
+
+## The legacy Bizinikiwi substream
+
+Bizinikiwi uses a component named the **peerset manager (PSM)**. Through the discovery
+mechanism, the PSM is aware of the nodes that are part of the network and decides which nodes
+we should perform Bizinikiwi-based communications with. For these nodes, we open a connection
+if necessary and open a unique substream for Bizinikiwi-based communications. If the PSM decides
+that we should disconnect a node, then that substream is closed.
+
+For more information about the PSM, see the *pezsc-peerset* crate.
+
+Note that at the moment there is no mechanism in place to solve the issues that arise where the
+two sides of a connection open the unique substream simultaneously. In order to not run into
+issues, only the dialer of a connection is allowed to open the unique substream. When the
+substream is closed, the entire connection is closed as well. This is a bug that will be
+resolved by deprecating the protocol entirely.
+
+Within the unique Bizinikiwi substream, messages encoded using
+[`parity-scale-codec``](https://github.com/paritytech/parity-scale-codec) are exchanged.
+The detail of theses messages is not totally in place, but they can be found in the
+`message.rs` file.
+
+Once the substream is open, the first step is an exchange of a *status* message from both
+sides, containing information such as the chain root hash, head of chain, and so on.
+
+Communications within this substream include:
+
+- Syncing. Blocks are announced and requested from other nodes.
+- Light-client requests. When a light client requires information, a random node we have a
+substream open with is chosen, and the information is requested from it.
+- Gossiping. Used for example by grandpa.
+
+## Request-response protocols
+
+A so-called request-response protocol is defined as follow:
+
+- When a substream is opened, the opening side sends a message whose content is
+protocol-specific. The message must be prefixed with an
+[LEB128-encoded number](https://en.wikipedia.org/wiki/LEB128) indicating its length. After the
+message has been sent, the writing side is closed.
+- The remote sends back the response prefixed with a LEB128-encoded length, and closes its
+side as well.
+
+Each request is performed in a new separate substream.
+
+## Notifications protocols
+
+A so-called notifications protocol is defined as follow:
+
+- When a substream is opened, the opening side sends a handshake message whose content is
+protocol-specific. The handshake message must be prefixed with an
+[LEB128-encoded number](https://en.wikipedia.org/wiki/LEB128) indicating its length. The
+handshake message can be of length 0, in which case the sender has to send a single `0`.
+- The receiver then either immediately closes the substream, or answers with its own
+LEB128-prefixed protocol-specific handshake response. The message can be of length 0, in which
+case a single `0` has to be sent back.
+- Once the handshake has completed, the notifications protocol is unidirectional. Only the
+node which initiated the substream can push notifications. If the remote wants to send
+notifications as well, it has to open its own undirectional substream.
+- Each notification must be prefixed with an LEB128-encoded length. The encoding of the
+messages is specific to each protocol.
+- Either party can signal that it doesn't want a notifications substream anymore by closing
+its writing side. The other party should respond by closing its own writing side soon after.
+
+The API of `pezsc-network` allows one to register user-defined notification protocols.
+`pezsc-network` automatically tries to open a substream towards each node for which the legacy
+Substream substream is open. The handshake is then performed automatically.
+
+For example, the `pezsc-consensus-grandpa` crate registers the `/paritytech/grandpa/1`
+notifications protocol.
+
+At the moment, for backwards-compatibility, notification protocols are tied to the legacy
+Bizinikiwi substream. Additionally, the handshake message is hardcoded to be a single 8-bits
+integer representing the role of the node:
+
+- 1 for a full node.
+- 2 for a light node.
+- 4 for an authority.
+
+In the future, though, these restrictions will be removed.
+
+# Sync
+
+The crate implements a number of syncing algorithms. The main purpose of the syncing algorithm is
+get the chain to the latest state and keep it synced with the rest of the network by downloading and
+importing new data as soon as it becomes available. Once the node starts it catches up with the network
+with one of the initial sync methods listed below, and once it is completed uses a keep-up sync to
+download new blocks.
+
+## Full and light sync
+
+This is the default syncing method for the initial and keep-up sync. The algorithm starts with the
+current best block and downloads block data progressively from multiple peers if available. Once
+there's a sequence of blocks ready to be imported they are fed to the import queue. Full nodes download
+and execute full blocks, while light nodes only download and import headers. This continues until each peers
+has no more new blocks to give.
+
+For each peer the sync maintains the number of our common best block with that peer. This number is updates
+whenever peer announce new blocks or our best block advances. This allows to keep track of peers that have new
+block data and request new information as soon as it is announced. In keep-up mode, we also track peers that
+announce blocks on all branches and not just the best branch. The sync algorithm tries to be greedy and download
+all data that's announced.
+
+## Fast sync
+
+In this mode the initial downloads and verifies full header history. This allows to validate
+authority set transitions and arrive at a recent header. After header chain is verified and imported
+the node starts downloading a state snapshot using the state request protocol. Each `StateRequest`
+contains a starting storage key, which is empty for the first request.
+`StateResponse` contains a storage proof for a sequence of keys and values in the storage
+starting (but not including) from the key that is in the request. After iterating the proof trie against
+the storage root that is in the target header, the node issues The next `StateRequest` with set starting
+key set to the last key from the previous response. This continues until trie iteration reaches the end.
+The state is then imported into the database and the keep-up sync starts in normal full/light sync mode.
+
+## Warp sync
+
+This is similar to fast sync, but instead of downloading and verifying full header chain, the algorithm
+only downloads finalized authority set changes.
+
+### GRANDPA warp sync
+
+GRANDPA keeps justifications for each finalized authority set change. Each change is signed by the
+authorities from the previous set. By downloading and verifying these signed hand-offs starting from genesis,
+we arrive at a recent header faster than downloading full header chain. Each `WarpSyncRequest` contains a block
+hash to start collecting proofs from. `WarpSyncResponse` contains a sequence of block headers and
+justifications. The proof downloader checks the justifications and continues requesting proofs from the last
+header hash, until it arrives at some recent header.
+
+Once the finality chain is proved for a header, the state matching the header is downloaded much like during
+the fast sync. The state is verified to match the header storage root. After the state is imported into the
+database it is queried for the information that allows GRANDPA and BABE to continue operating from that state.
+This includes BABE epoch information and GRANDPA authority set id.
+
+### Background block download
+
+After the latest state has been imported the node is fully operational, but is still missing historic block
+data. I.e. it is unable to serve bock bodies and headers other than the most recent one. To make sure all
+nodes have block history available, a background sync process is started that downloads all the missing blocks.
+It is run in parallel with the keep-up sync and does not interfere with downloading of the recent blocks.
+During this download we also import GRANDPA justifications for blocks with authority set changes, so that
+the warp-synced node has all the data to serve for other nodes that might want to sync from it with
+any method.
+
+# Usage
+
+Using the `pezsc-network` crate is done through the [`NetworkWorker`] struct. Create this
+struct by passing a [`config::Params`], then poll it as if it was a `Future`. You can extract an
+`Arc<NetworkService>` from the `NetworkWorker`, which can be shared amongst multiple places
+in order to give orders to the networking.
+
+See the [`config`] module for more information about how to configure the networking.
+
+After the `NetworkWorker` has been created, the important things to do are:
+
+- Calling `NetworkWorker::poll` in order to advance the network. This can be done by
+dispatching a background task with the [`NetworkWorker`].
+- Calling `on_block_import` whenever a block is added to the client.
+- Calling `on_block_finalized` whenever a block is finalized.
+- Calling `trigger_repropagate` when a transaction is added to the pool.
+
+More precise usage details are still being worked on and will likely change in the future.
+
+
+License: GPL-3.0-or-later WITH Classpath-exception-2.0

bizinikiwi/client/network/benches/notifications_protocol.rs

@@ -0,0 +1,311 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use criterion::{
+	criterion_group, criterion_main, AxisScale, BenchmarkId, Criterion, PlotConfiguration,
+	Throughput,
+};
+use pezsc_network::{
+	config::{
+		FullNetworkConfiguration, MultiaddrWithPeerId, NetworkConfiguration, NonReservedPeerMode,
+		NotificationHandshake, Params, ProtocolId, Role, SetConfig,
+	},
+	service::traits::{NetworkService, NotificationEvent},
+	Litep2pNetworkBackend, NetworkBackend, NetworkWorker, NotificationMetrics, NotificationService,
+	PeerId, Roles,
+};
+use pezsc_network_common::{sync::message::BlockAnnouncesHandshake, ExHashT};
+use pezsp_core::H256;
+use pezsp_runtime::traits::{Block as BlockT, Zero};
+use std::{sync::Arc, time::Duration};
+use bizinikiwi_test_runtime_client::runtime;
+use tokio::{sync::Mutex, task::JoinHandle};
+
+const NUMBER_OF_NOTIFICATIONS: usize = 100;
+const PAYLOAD: &[(u32, &'static str)] = &[
+	// (Exponent of size, label)
+	(6, "64B"),
+	(9, "512B"),
+	(12, "4KB"),
+	(15, "64KB"),
+	(18, "256KB"),
+	(21, "2MB"),
+	(24, "16MB"),
+];
+const MAX_SIZE: u64 = 2u64.pow(30);
+
+fn create_network_worker<B, H, N>(
+) -> (N, Arc<dyn NetworkService>, Arc<Mutex<Box<dyn NotificationService>>>)
+where
+	B: BlockT<Hash = H256> + 'static,
+	H: ExHashT,
+	N: NetworkBackend<B, H>,
+{
+	let role = Role::Full;
+	let net_conf = NetworkConfiguration::new_local();
+	let network_config = FullNetworkConfiguration::<B, H, N>::new(&net_conf, None);
+	let genesis_hash = runtime::Hash::zero();
+	let (block_announce_config, notification_service) = N::notification_config(
+		"/block-announces/1".into(),
+		vec!["/bench-notifications-protocol/block-announces/1".into()],
+		MAX_SIZE,
+		Some(NotificationHandshake::new(BlockAnnouncesHandshake::<runtime::Block>::build(
+			Roles::from(&role),
+			Zero::zero(),
+			genesis_hash,
+			genesis_hash,
+		))),
+		SetConfig {
+			in_peers: 1,
+			out_peers: 1,
+			reserved_nodes: vec![],
+			non_reserved_mode: NonReservedPeerMode::Accept,
+		},
+		NotificationMetrics::new(None),
+		network_config.peer_store_handle(),
+	);
+	let worker = N::new(Params::<B, H, N> {
+		block_announce_config,
+		role,
+		executor: Box::new(|f| {
+			tokio::spawn(f);
+		}),
+		genesis_hash,
+		network_config,
+		protocol_id: ProtocolId::from("bench-protocol-name"),
+		fork_id: None,
+		metrics_registry: None,
+		bitswap_config: None,
+		notification_metrics: NotificationMetrics::new(None),
+	})
+	.unwrap();
+	let network_service = worker.network_service();
+	let notification_service = Arc::new(Mutex::new(notification_service));
+
+	(worker, network_service, notification_service)
+}
+
+struct BenchSetup {
+	notification_service1: Arc<Mutex<Box<dyn NotificationService>>>,
+	notification_service2: Arc<Mutex<Box<dyn NotificationService>>>,
+	peer_id2: PeerId,
+	handle1: JoinHandle<()>,
+	handle2: JoinHandle<()>,
+}
+
+impl Drop for BenchSetup {
+	fn drop(&mut self) {
+		self.handle1.abort();
+		self.handle2.abort();
+	}
+}
+
+fn setup_workers<B, H, N>(rt: &tokio::runtime::Runtime) -> Arc<BenchSetup>
+where
+	B: BlockT<Hash = H256> + 'static,
+	H: ExHashT,
+	N: NetworkBackend<B, H>,
+{
+	let _guard = rt.enter();
+
+	let (worker1, network_service1, notification_service1) = create_network_worker::<B, H, N>();
+	let (worker2, network_service2, notification_service2) = create_network_worker::<B, H, N>();
+	let peer_id2: pezsc_network::PeerId = network_service2.local_peer_id().into();
+	let handle1 = tokio::spawn(worker1.run());
+	let handle2 = tokio::spawn(worker2.run());
+
+	let ready = tokio::spawn({
+		let notification_service1 = Arc::clone(&notification_service1);
+		let notification_service2 = Arc::clone(&notification_service2);
+
+		async move {
+			let listen_address2 = {
+				while network_service2.listen_addresses().is_empty() {
+					tokio::time::sleep(Duration::from_millis(10)).await;
+				}
+				network_service2.listen_addresses()[0].clone()
+			};
+			network_service1
+				.add_reserved_peer(MultiaddrWithPeerId {
+					multiaddr: listen_address2,
+					peer_id: peer_id2,
+				})
+				.unwrap();
+
+			let mut notification_service1 = notification_service1.lock().await;
+			let mut notification_service2 = notification_service2.lock().await;
+			loop {
+				tokio::select! {
+					Some(event) = notification_service1.next_event() => {
+						if let NotificationEvent::NotificationStreamOpened { .. } = event {
+							// Send a 32MB notification to preheat the network
+							notification_service1.send_async_notification(&peer_id2, vec![0; 2usize.pow(25)]).await.unwrap();
+						}
+					},
+					Some(event) = notification_service2.next_event() => {
+						match event {
+							NotificationEvent::ValidateInboundSubstream { result_tx, .. } => {
+								result_tx.send(pezsc_network::service::traits::ValidationResult::Accept).unwrap();
+							},
+							NotificationEvent::NotificationReceived { .. } => {
+								break;
+							}
+							_ => {}
+						}
+					},
+				}
+			}
+		}
+	});
+
+	tokio::task::block_in_place(|| {
+		let _ = tokio::runtime::Handle::current().block_on(ready);
+	});
+
+	Arc::new(BenchSetup {
+		notification_service1,
+		notification_service2,
+		peer_id2,
+		handle1,
+		handle2,
+	})
+}
+
+async fn run_serially(setup: Arc<BenchSetup>, size: usize, limit: usize) {
+	let (tx, rx) = async_channel::bounded(1);
+	let _ = tx.send(Some(())).await;
+	let network1 = tokio::spawn({
+		let notification_service1 = Arc::clone(&setup.notification_service1);
+		let peer_id2 = setup.peer_id2;
+		async move {
+			let mut notification_service1 = notification_service1.lock().await;
+			while let Ok(message) = rx.recv().await {
+				let Some(_) = message else { break };
+				notification_service1
+					.send_async_notification(&peer_id2, vec![0; size])
+					.await
+					.unwrap();
+			}
+		}
+	});
+	let network2 = tokio::spawn({
+		let notification_service2 = Arc::clone(&setup.notification_service2);
+		async move {
+			let mut notification_service2 = notification_service2.lock().await;
+			let mut received_counter = 0;
+			while let Some(event) = notification_service2.next_event().await {
+				if let NotificationEvent::NotificationReceived { .. } = event {
+					received_counter += 1;
+					if received_counter >= limit {
+						let _ = tx.send(None).await;
+						break;
+					}
+					let _ = tx.send(Some(())).await;
+				}
+			}
+		}
+	});
+
+	let _ = tokio::join!(network1, network2);
+}
+
+async fn run_with_backpressure(setup: Arc<BenchSetup>, size: usize, limit: usize) {
+	let (tx, rx) = async_channel::bounded(1);
+	let network1 = tokio::spawn({
+		let setup = Arc::clone(&setup);
+		async move {
+			let mut notification_service1 = setup.notification_service1.lock().await;
+			for _ in 0..limit {
+				notification_service1
+					.send_async_notification(&setup.peer_id2, vec![0; size])
+					.await
+					.unwrap();
+			}
+			let _ = rx.recv().await;
+		}
+	});
+	let network2 = tokio::spawn({
+		let setup = Arc::clone(&setup);
+		async move {
+			let mut notification_service2 = setup.notification_service2.lock().await;
+			let mut received_counter = 0;
+			while let Some(event) = notification_service2.next_event().await {
+				if let NotificationEvent::NotificationReceived { .. } = event {
+					received_counter += 1;
+					if received_counter >= limit {
+						let _ = tx.send(()).await;
+						break;
+					}
+				}
+			}
+		}
+	});
+
+	let _ = tokio::join!(network1, network2);
+}
+
+fn run_benchmark(c: &mut Criterion) {
+	let rt = tokio::runtime::Runtime::new().unwrap();
+	let plot_config = PlotConfiguration::default().summary_scale(AxisScale::Logarithmic);
+	let mut group = c.benchmark_group("notifications_protocol");
+	group.plot_config(plot_config);
+	group.sample_size(10);
+
+	let libp2p_setup = setup_workers::<runtime::Block, runtime::Hash, NetworkWorker<_, _>>(&rt);
+	for &(exponent, label) in PAYLOAD.iter() {
+		let size = 2usize.pow(exponent);
+		group.throughput(Throughput::Bytes(NUMBER_OF_NOTIFICATIONS as u64 * size as u64));
+		group.bench_with_input(BenchmarkId::new("libp2p/serially", label), &size, |b, &size| {
+			b.to_async(&rt)
+				.iter(|| run_serially(Arc::clone(&libp2p_setup), size, NUMBER_OF_NOTIFICATIONS));
+		});
+		group.bench_with_input(
+			BenchmarkId::new("libp2p/with_backpressure", label),
+			&size,
+			|b, &size| {
+				b.to_async(&rt).iter(|| {
+					run_with_backpressure(Arc::clone(&libp2p_setup), size, NUMBER_OF_NOTIFICATIONS)
+				});
+			},
+		);
+	}
+	drop(libp2p_setup);
+
+	let litep2p_setup = setup_workers::<runtime::Block, runtime::Hash, Litep2pNetworkBackend>(&rt);
+	for &(exponent, label) in PAYLOAD.iter() {
+		let size = 2usize.pow(exponent);
+		group.throughput(Throughput::Bytes(NUMBER_OF_NOTIFICATIONS as u64 * size as u64));
+		group.bench_with_input(BenchmarkId::new("litep2p/serially", label), &size, |b, &size| {
+			b.to_async(&rt)
+				.iter(|| run_serially(Arc::clone(&litep2p_setup), size, NUMBER_OF_NOTIFICATIONS));
+		});
+		group.bench_with_input(
+			BenchmarkId::new("litep2p/with_backpressure", label),
+			&size,
+			|b, &size| {
+				b.to_async(&rt).iter(|| {
+					run_with_backpressure(Arc::clone(&litep2p_setup), size, NUMBER_OF_NOTIFICATIONS)
+				});
+			},
+		);
+	}
+	drop(litep2p_setup);
+}
+
+criterion_group!(benches, run_benchmark);
+criterion_main!(benches);

bizinikiwi/client/network/benches/request_response_protocol.rs

@@ -0,0 +1,325 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use criterion::{
+	criterion_group, criterion_main, AxisScale, BenchmarkId, Criterion, PlotConfiguration,
+	Throughput,
+};
+use pezsc_network::{
+	config::{
+		FullNetworkConfiguration, IncomingRequest, NetworkConfiguration, NonReservedPeerMode,
+		NotificationHandshake, OutgoingResponse, Params, ProtocolId, Role, SetConfig,
+	},
+	service::traits::NetworkService,
+	IfDisconnected, Litep2pNetworkBackend, NetworkBackend, NetworkRequest, NetworkWorker,
+	NotificationMetrics, NotificationService, PeerId, Roles,
+};
+use pezsc_network_common::{sync::message::BlockAnnouncesHandshake, ExHashT};
+use pezsp_core::H256;
+use pezsp_runtime::traits::{Block as BlockT, Zero};
+use std::{sync::Arc, time::Duration};
+use bizinikiwi_test_runtime_client::runtime;
+use tokio::{sync::Mutex, task::JoinHandle};
+
+const MAX_SIZE: u64 = 2u64.pow(30);
+const NUMBER_OF_REQUESTS: usize = 100;
+const PAYLOAD: &[(u32, &'static str)] = &[
+	// (Exponent of size, label)
+	(6, "64B"),
+	(9, "512B"),
+	(12, "4KB"),
+	(15, "64KB"),
+	(18, "256KB"),
+	(21, "2MB"),
+	(24, "16MB"),
+];
+
+pub fn create_network_worker<B, H, N>() -> (
+	N,
+	Arc<dyn NetworkService>,
+	async_channel::Receiver<IncomingRequest>,
+	Arc<Mutex<Box<dyn NotificationService>>>,
+)
+where
+	B: BlockT<Hash = H256> + 'static,
+	H: ExHashT,
+	N: NetworkBackend<B, H>,
+{
+	let (tx, rx) = async_channel::bounded(10);
+	let request_response_config = N::request_response_config(
+		"/request-response/1".into(),
+		vec![],
+		MAX_SIZE,
+		MAX_SIZE,
+		Duration::from_secs(2),
+		Some(tx),
+	);
+	let role = Role::Full;
+	let net_conf = NetworkConfiguration::new_local();
+	let mut network_config = FullNetworkConfiguration::new(&net_conf, None);
+	network_config.add_request_response_protocol(request_response_config);
+	let genesis_hash = runtime::Hash::zero();
+	let (block_announce_config, notification_service) = N::notification_config(
+		"/block-announces/1".into(),
+		vec![],
+		1024,
+		Some(NotificationHandshake::new(BlockAnnouncesHandshake::<runtime::Block>::build(
+			Roles::from(&Role::Full),
+			Zero::zero(),
+			genesis_hash,
+			genesis_hash,
+		))),
+		SetConfig {
+			in_peers: 1,
+			out_peers: 1,
+			reserved_nodes: vec![],
+			non_reserved_mode: NonReservedPeerMode::Accept,
+		},
+		NotificationMetrics::new(None),
+		network_config.peer_store_handle(),
+	);
+	let worker = N::new(Params::<B, H, N> {
+		block_announce_config,
+		role,
+		executor: Box::new(|f| {
+			tokio::spawn(f);
+		}),
+		genesis_hash: runtime::Hash::zero(),
+		network_config,
+		protocol_id: ProtocolId::from("bench-request-response-protocol"),
+		fork_id: None,
+		metrics_registry: None,
+		bitswap_config: None,
+		notification_metrics: NotificationMetrics::new(None),
+	})
+	.unwrap();
+	let notification_service = Arc::new(Mutex::new(notification_service));
+	let network_service = worker.network_service();
+
+	(worker, network_service, rx, notification_service)
+}
+
+struct BenchSetup {
+	#[allow(dead_code)]
+	notification_service1: Arc<Mutex<Box<dyn NotificationService>>>,
+	#[allow(dead_code)]
+	notification_service2: Arc<Mutex<Box<dyn NotificationService>>>,
+	network_service1: Arc<dyn NetworkService>,
+	peer_id2: PeerId,
+	handle1: JoinHandle<()>,
+	handle2: JoinHandle<()>,
+	#[allow(dead_code)]
+	rx1: async_channel::Receiver<IncomingRequest>,
+	rx2: async_channel::Receiver<IncomingRequest>,
+}
+
+impl Drop for BenchSetup {
+	fn drop(&mut self) {
+		self.handle1.abort();
+		self.handle2.abort();
+	}
+}
+
+fn setup_workers<B, H, N>(rt: &tokio::runtime::Runtime) -> Arc<BenchSetup>
+where
+	B: BlockT<Hash = H256> + 'static,
+	H: ExHashT,
+	N: NetworkBackend<B, H>,
+{
+	let _guard = rt.enter();
+
+	let (worker1, network_service1, rx1, notification_service1) =
+		create_network_worker::<B, H, N>();
+	let (worker2, network_service2, rx2, notification_service2) =
+		create_network_worker::<B, H, N>();
+	let peer_id2 = worker2.network_service().local_peer_id();
+	let handle1 = tokio::spawn(worker1.run());
+	let handle2 = tokio::spawn(worker2.run());
+
+	let _ = tokio::spawn({
+		let rx2 = rx2.clone();
+
+		async move {
+			let req = rx2.recv().await.unwrap();
+			req.pending_response
+				.send(OutgoingResponse {
+					result: Ok(vec![0; 2usize.pow(25)]),
+					reputation_changes: vec![],
+					sent_feedback: None,
+				})
+				.unwrap();
+		}
+	});
+
+	let ready = tokio::spawn({
+		let network_service1 = Arc::clone(&network_service1);
+
+		async move {
+			let listen_address2 = {
+				while network_service2.listen_addresses().is_empty() {
+					tokio::time::sleep(Duration::from_millis(10)).await;
+				}
+				network_service2.listen_addresses()[0].clone()
+			};
+			network_service1.add_known_address(peer_id2, listen_address2.into());
+			let _ = network_service1
+				.request(
+					peer_id2.into(),
+					"/request-response/1".into(),
+					vec![0; 2],
+					None,
+					IfDisconnected::TryConnect,
+				)
+				.await
+				.unwrap();
+		}
+	});
+
+	tokio::task::block_in_place(|| {
+		let _ = tokio::runtime::Handle::current().block_on(ready);
+	});
+
+	Arc::new(BenchSetup {
+		notification_service1,
+		notification_service2,
+		network_service1,
+		peer_id2,
+		handle1,
+		handle2,
+		rx1,
+		rx2,
+	})
+}
+
+async fn run_serially(setup: Arc<BenchSetup>, size: usize, limit: usize) {
+	let (break_tx, break_rx) = async_channel::bounded(1);
+	let network1 = tokio::spawn({
+		let network_service1 = Arc::clone(&setup.network_service1);
+		let peer_id2 = setup.peer_id2;
+		async move {
+			for _ in 0..limit {
+				let _ = network_service1
+					.request(
+						peer_id2.into(),
+						"/request-response/1".into(),
+						vec![0; 2],
+						None,
+						IfDisconnected::TryConnect,
+					)
+					.await
+					.unwrap();
+			}
+			let _ = break_tx.send(()).await;
+		}
+	});
+	let network2 = tokio::spawn({
+		let rx2 = setup.rx2.clone();
+		async move {
+			loop {
+				tokio::select! {
+					req = rx2.recv() => {
+						let IncomingRequest { pending_response, .. } = req.unwrap();
+						pending_response.send(OutgoingResponse {
+							result: Ok(vec![0; size]),
+							reputation_changes: vec![],
+							sent_feedback: None,
+						}).unwrap();
+					},
+					_ = break_rx.recv() => break,
+				}
+			}
+		}
+	});
+
+	let _ = tokio::join!(network1, network2);
+}
+
+// The libp2p request-response implementation does not provide any backpressure feedback.
+// So this benchmark is useless until we implement it for litep2p.
+#[allow(dead_code)]
+async fn run_with_backpressure(setup: Arc<BenchSetup>, size: usize, limit: usize) {
+	let (break_tx, break_rx) = async_channel::bounded(1);
+	let requests = futures::future::join_all((0..limit).into_iter().map(|_| {
+		let (tx, rx) = futures::channel::oneshot::channel();
+		setup.network_service1.start_request(
+			setup.peer_id2.into(),
+			"/request-response/1".into(),
+			vec![0; 8],
+			None,
+			tx,
+			IfDisconnected::TryConnect,
+		);
+		rx
+	}));
+
+	let network1 = tokio::spawn(async move {
+		let responses = requests.await;
+		for res in responses {
+			res.unwrap().unwrap();
+		}
+		let _ = break_tx.send(()).await;
+	});
+	let network2 = tokio::spawn(async move {
+		for _ in 0..limit {
+			let IncomingRequest { pending_response, .. } = setup.rx2.recv().await.unwrap();
+			pending_response
+				.send(OutgoingResponse {
+					result: Ok(vec![0; size]),
+					reputation_changes: vec![],
+					sent_feedback: None,
+				})
+				.unwrap();
+		}
+		break_rx.recv().await
+	});
+
+	let _ = tokio::join!(network1, network2);
+}
+
+fn run_benchmark(c: &mut Criterion) {
+	let rt = tokio::runtime::Runtime::new().unwrap();
+	let plot_config = PlotConfiguration::default().summary_scale(AxisScale::Logarithmic);
+	let mut group = c.benchmark_group("request_response_protocol");
+	group.plot_config(plot_config);
+	group.sample_size(10);
+
+	let libp2p_setup = setup_workers::<runtime::Block, runtime::Hash, NetworkWorker<_, _>>(&rt);
+	for &(exponent, label) in PAYLOAD.iter() {
+		let size = 2usize.pow(exponent);
+		group.throughput(Throughput::Bytes(NUMBER_OF_REQUESTS as u64 * size as u64));
+		group.bench_with_input(BenchmarkId::new("libp2p/serially", label), &size, |b, &size| {
+			b.to_async(&rt)
+				.iter(|| run_serially(Arc::clone(&libp2p_setup), size, NUMBER_OF_REQUESTS));
+		});
+	}
+	drop(libp2p_setup);
+
+	let litep2p_setup = setup_workers::<runtime::Block, runtime::Hash, Litep2pNetworkBackend>(&rt);
+	for &(exponent, label) in PAYLOAD.iter() {
+		let size = 2usize.pow(exponent);
+		group.throughput(Throughput::Bytes(NUMBER_OF_REQUESTS as u64 * size as u64));
+		group.bench_with_input(BenchmarkId::new("litep2p/serially", label), &size, |b, &size| {
+			b.to_async(&rt)
+				.iter(|| run_serially(Arc::clone(&litep2p_setup), size, NUMBER_OF_REQUESTS));
+		});
+	}
+	drop(litep2p_setup);
+}
+
+criterion_group!(benches, run_benchmark);
+criterion_main!(benches);

bizinikiwi/client/network/build.rs

@@ -0,0 +1,23 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+const PROTOS: &[&str] = &["src/schema/bitswap.v1.2.0.proto"];
+
+fn main() {
+	prost_build::compile_protos(PROTOS, &["src/schema"]).unwrap();
+}

bizinikiwi/client/network/common/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+description = "Bizinikiwi network common"
+name = "pezsc-network-common"
+version = "0.33.0"
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+authors.workspace = true
+edition.workspace = true
+homepage.workspace = true
+repository.workspace = true
+documentation = "https://docs.rs/pezsc-network-sync"
+
+[lints]
+workspace = true
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+bitflags = { workspace = true }
+codec = { features = ["derive"], workspace = true, default-features = true }
+pezsp-runtime = { workspace = true, default-features = true }
+
+[features]
+runtime-benchmarks = ["pezsp-runtime/runtime-benchmarks"]

bizinikiwi/client/network/common/src/lib.rs

@@ -0,0 +1,30 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Common data structures of the networking layer.
+
+pub mod message;
+pub mod role;
+pub mod sync;
+pub mod types;
+
+/// Minimum Requirements for a Hash within Networking
+pub trait ExHashT: std::hash::Hash + Eq + std::fmt::Debug + Clone + Send + Sync + 'static {}
+
+impl<T> ExHashT for T where T: std::hash::Hash + Eq + std::fmt::Debug + Clone + Send + Sync + 'static
+{}

bizinikiwi/client/network/common/src/message.rs

@@ -0,0 +1,23 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Network packet message types. These get serialized and put into the lower level protocol
+//! payload.
+
+/// A unique ID of a request.
+pub type RequestId = u64;

bizinikiwi/client/network/common/src/role.rs

@@ -0,0 +1,137 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+// file-level lint whitelist to avoid problem with bitflags macro below
+// TODO: can be dropped after an update to bitflags 2.4
+#![allow(clippy::bad_bit_mask)]
+
+use codec::{self, Encode, EncodeLike, Input, Output};
+
+/// Role that the peer sent to us during the handshake, with the addition of what our local node
+/// knows about that peer.
+///
+/// > **Note**: This enum is different from the `Role` enum. The `Role` enum indicates what a
+/// >			node says about itself, while `ObservedRole` is a `Role` merged with the
+/// >			information known locally about that node.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum ObservedRole {
+	/// Full node.
+	Full,
+	/// Light node.
+	Light,
+	/// Third-party authority.
+	Authority,
+}
+
+impl ObservedRole {
+	/// Returns `true` for `ObservedRole::Light`.
+	pub fn is_light(&self) -> bool {
+		matches!(self, Self::Light)
+	}
+}
+
+impl From<Roles> for ObservedRole {
+	fn from(roles: Roles) -> Self {
+		if roles.is_authority() {
+			ObservedRole::Authority
+		} else if roles.is_full() {
+			ObservedRole::Full
+		} else {
+			ObservedRole::Light
+		}
+	}
+}
+
+/// Role of the local node.
+#[derive(Debug, Clone, Copy)]
+pub enum Role {
+	/// Regular full node.
+	Full,
+	/// Actual authority.
+	Authority,
+}
+
+impl Role {
+	/// True for [`Role::Authority`].
+	pub fn is_authority(&self) -> bool {
+		matches!(self, Self::Authority)
+	}
+}
+
+impl std::fmt::Display for Role {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		match self {
+			Self::Full => write!(f, "FULL"),
+			Self::Authority => write!(f, "AUTHORITY"),
+		}
+	}
+}
+
+bitflags::bitflags! {
+	/// Bitmask of the roles that a node fulfills.
+	pub struct Roles: u8 {
+		/// No network.
+		const NONE = 0b00000000;
+		/// Full node, does not participate in consensus.
+		const FULL = 0b00000001;
+		/// Light client node.
+		const LIGHT = 0b00000010;
+		/// Act as an authority
+		const AUTHORITY = 0b00000100;
+	}
+}
+
+impl Roles {
+	/// Does this role represents a client that holds full chain data locally?
+	pub fn is_full(&self) -> bool {
+		self.intersects(Self::FULL | Self::AUTHORITY)
+	}
+
+	/// Does this role represents a client that does not participates in the consensus?
+	pub fn is_authority(&self) -> bool {
+		*self == Self::AUTHORITY
+	}
+
+	/// Does this role represents a client that does not hold full chain data locally?
+	pub fn is_light(&self) -> bool {
+		!self.is_full()
+	}
+}
+
+impl<'a> From<&'a Role> for Roles {
+	fn from(roles: &'a Role) -> Self {
+		match roles {
+			Role::Full => Self::FULL,
+			Role::Authority => Self::AUTHORITY,
+		}
+	}
+}
+
+impl Encode for Roles {
+	fn encode_to<T: Output + ?Sized>(&self, dest: &mut T) {
+		dest.push_byte(self.bits())
+	}
+}
+
+impl EncodeLike for Roles {}
+
+impl codec::Decode for Roles {
+	fn decode<I: Input>(input: &mut I) -> Result<Self, codec::Error> {
+		Self::from_bits(input.read_byte()?).ok_or_else(|| codec::Error::from("Invalid bytes"))
+	}
+}

bizinikiwi/client/network/common/src/sync.rs

@@ -0,0 +1,55 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Abstract interfaces and data structures related to network sync.
+
+pub mod message;
+
+/// Sync operation mode.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum SyncMode {
+	/// Full block download and verification.
+	Full,
+	/// Download blocks and the latest state.
+	LightState {
+		/// Skip state proof download and verification.
+		skip_proofs: bool,
+		/// Download indexed transactions for recent blocks.
+		storage_chain_mode: bool,
+	},
+	/// Warp sync - verify authority set transitions and the latest state.
+	Warp,
+}
+
+impl SyncMode {
+	/// Returns `true` if `self` is [`Self::Warp`].
+	pub fn is_warp(&self) -> bool {
+		matches!(self, Self::Warp)
+	}
+
+	/// Returns `true` if `self` is [`Self::LightState`].
+	pub fn light_state(&self) -> bool {
+		matches!(self, Self::LightState { .. })
+	}
+}
+
+impl Default for SyncMode {
+	fn default() -> Self {
+		Self::Full
+	}
+}

bizinikiwi/client/network/common/src/sync/message.rs

@@ -0,0 +1,246 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Network packet message types. These get serialized and put into the lower level protocol
+//! payload.
+
+use crate::role::Roles;
+
+use bitflags::bitflags;
+use codec::{Decode, Encode, Error, Input, Output};
+pub use generic::{BlockAnnounce, FromBlock};
+use pezsp_runtime::traits::{Block as BlockT, Header as HeaderT, NumberFor};
+
+/// Type alias for using the block request type using block type parameters.
+pub type BlockRequest<B> =
+	generic::BlockRequest<<B as BlockT>::Hash, <<B as BlockT>::Header as HeaderT>::Number>;
+
+/// Type alias for using the BlockData type using block type parameters.
+pub type BlockData<B> =
+	generic::BlockData<<B as BlockT>::Header, <B as BlockT>::Hash, <B as BlockT>::Extrinsic>;
+
+/// Type alias for using the BlockResponse type using block type parameters.
+pub type BlockResponse<B> =
+	generic::BlockResponse<<B as BlockT>::Header, <B as BlockT>::Hash, <B as BlockT>::Extrinsic>;
+
+// Bits of block data and associated artifacts to request.
+bitflags! {
+	/// Node roles bitmask.
+	pub struct BlockAttributes: u8 {
+		/// Include block header.
+		const HEADER = 0b00000001;
+		/// Include block body.
+		const BODY = 0b00000010;
+		/// Include block receipt.
+		const RECEIPT = 0b00000100;
+		/// Include block message queue.
+		const MESSAGE_QUEUE = 0b00001000;
+		/// Include a justification for the block.
+		const JUSTIFICATION = 0b00010000;
+		/// Include indexed transactions for a block.
+		const INDEXED_BODY = 0b00100000;
+	}
+}
+
+impl BlockAttributes {
+	/// Encodes attributes as big endian u32, compatible with SCALE-encoding (i.e the
+	/// significant byte has zero index).
+	pub fn to_be_u32(&self) -> u32 {
+		u32::from_be_bytes([self.bits(), 0, 0, 0])
+	}
+
+	/// Decodes attributes, encoded with the `encode_to_be_u32()` call.
+	pub fn from_be_u32(encoded: u32) -> Result<Self, Error> {
+		Self::from_bits(encoded.to_be_bytes()[0])
+			.ok_or_else(|| Error::from("Invalid BlockAttributes"))
+	}
+}
+
+impl Encode for BlockAttributes {
+	fn encode_to<T: Output + ?Sized>(&self, dest: &mut T) {
+		dest.push_byte(self.bits())
+	}
+}
+
+impl codec::EncodeLike for BlockAttributes {}
+
+impl Decode for BlockAttributes {
+	fn decode<I: Input>(input: &mut I) -> Result<Self, Error> {
+		Self::from_bits(input.read_byte()?).ok_or_else(|| Error::from("Invalid bytes"))
+	}
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Encode, Decode)]
+/// Block enumeration direction.
+pub enum Direction {
+	/// Enumerate in ascending order (from child to parent).
+	Ascending = 0,
+	/// Enumerate in descending order (from parent to canonical child).
+	Descending = 1,
+}
+
+/// Block state in the chain.
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Encode, Decode)]
+pub enum BlockState {
+	/// Block is not part of the best chain.
+	Normal,
+	/// Latest best block.
+	Best,
+}
+
+/// Announcement summary used for debug logging.
+#[derive(Debug)]
+pub struct AnnouncementSummary<H: HeaderT> {
+	pub block_hash: H::Hash,
+	pub number: H::Number,
+	pub parent_hash: H::Hash,
+	pub state: Option<BlockState>,
+}
+
+impl<H: HeaderT> BlockAnnounce<H> {
+	pub fn summary(&self) -> AnnouncementSummary<H> {
+		AnnouncementSummary {
+			block_hash: self.header.hash(),
+			number: *self.header.number(),
+			parent_hash: *self.header.parent_hash(),
+			state: self.state,
+		}
+	}
+}
+
+/// Generic types.
+pub mod generic {
+	use super::{BlockAttributes, BlockState, Direction};
+	use crate::message::RequestId;
+	use codec::{Decode, Encode, Input, Output};
+	use pezsp_runtime::{EncodedJustification, Justifications};
+
+	/// Block data sent in the response.
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	pub struct BlockData<Header, Hash, Extrinsic> {
+		/// Block header hash.
+		pub hash: Hash,
+		/// Block header if requested.
+		pub header: Option<Header>,
+		/// Block body if requested.
+		pub body: Option<Vec<Extrinsic>>,
+		/// Block body indexed transactions if requested.
+		pub indexed_body: Option<Vec<Vec<u8>>>,
+		/// Block receipt if requested.
+		pub receipt: Option<Vec<u8>>,
+		/// Block message queue if requested.
+		pub message_queue: Option<Vec<u8>>,
+		/// Justification if requested.
+		pub justification: Option<EncodedJustification>,
+		/// Justifications if requested.
+		pub justifications: Option<Justifications>,
+	}
+
+	/// Request block data from a peer.
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	pub struct BlockRequest<Hash, Number> {
+		/// Unique request id.
+		pub id: RequestId,
+		/// Bits of block data to request.
+		pub fields: BlockAttributes,
+		/// Start from this block.
+		pub from: FromBlock<Hash, Number>,
+		/// Sequence direction.
+		pub direction: Direction,
+		/// Maximum number of blocks to return. An implementation defined maximum is used when
+		/// unspecified.
+		pub max: Option<u32>,
+	}
+
+	/// Identifies starting point of a block sequence.
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	pub enum FromBlock<Hash, Number> {
+		/// Start with given hash.
+		Hash(Hash),
+		/// Start with given block number.
+		Number(Number),
+	}
+
+	/// Response to `BlockRequest`
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	pub struct BlockResponse<Header, Hash, Extrinsic> {
+		/// Id of a request this response was made for.
+		pub id: RequestId,
+		/// Block data for the requested sequence.
+		pub blocks: Vec<BlockData<Header, Hash, Extrinsic>>,
+	}
+
+	/// Announce a new complete block on the network.
+	#[derive(Debug, PartialEq, Eq, Clone)]
+	pub struct BlockAnnounce<H> {
+		/// New block header.
+		pub header: H,
+		/// Block state. TODO: Remove `Option` and custom encoding when v4 becomes common.
+		pub state: Option<BlockState>,
+		/// Data associated with this block announcement, e.g. a candidate message.
+		pub data: Option<Vec<u8>>,
+	}
+
+	// Custom Encode/Decode impl to maintain backwards compatibility with v3.
+	// This assumes that the packet contains nothing but the announcement message.
+	// TODO: Get rid of it once protocol v4 is common.
+	impl<H: Encode> Encode for BlockAnnounce<H> {
+		fn encode_to<T: Output + ?Sized>(&self, dest: &mut T) {
+			self.header.encode_to(dest);
+			if let Some(state) = &self.state {
+				state.encode_to(dest);
+			}
+			if let Some(data) = &self.data {
+				data.encode_to(dest)
+			}
+		}
+	}
+
+	impl<H: Decode> Decode for BlockAnnounce<H> {
+		fn decode<I: Input>(input: &mut I) -> Result<Self, codec::Error> {
+			let header = H::decode(input)?;
+			let state = BlockState::decode(input).ok();
+			let data = Vec::decode(input).ok();
+			Ok(Self { header, state, data })
+		}
+	}
+}
+
+/// Handshake sent when we open a block announces substream.
+#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+pub struct BlockAnnouncesHandshake<B: BlockT> {
+	/// Roles of the node.
+	pub roles: Roles,
+	/// Best block number.
+	pub best_number: NumberFor<B>,
+	/// Best block hash.
+	pub best_hash: B::Hash,
+	/// Genesis block hash.
+	pub genesis_hash: B::Hash,
+}
+
+impl<B: BlockT> BlockAnnouncesHandshake<B> {
+	pub fn build(
+		roles: Roles,
+		best_number: NumberFor<B>,
+		best_hash: B::Hash,
+		genesis_hash: B::Hash,
+	) -> Self {
+		Self { genesis_hash, roles, best_number, best_hash }
+	}
+}

bizinikiwi/client/network/common/src/types.rs

@@ -0,0 +1,38 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+/// Description of a reputation adjustment for a node.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct ReputationChange {
+	/// Reputation delta.
+	pub value: i32,
+	/// Reason for reputation change.
+	pub reason: &'static str,
+}
+
+impl ReputationChange {
+	/// New reputation change with given delta and reason.
+	pub const fn new(value: i32, reason: &'static str) -> ReputationChange {
+		Self { value, reason }
+	}
+
+	/// New reputation change that forces minimum possible reputation.
+	pub const fn new_fatal(reason: &'static str) -> ReputationChange {
+		Self { value: i32::MIN, reason }
+	}
+}

bizinikiwi/client/network/light/Cargo.toml

@@ -0,0 +1,42 @@
+[package]
+description = "Bizinikiwi light network protocol"
+name = "pezsc-network-light"
+version = "0.33.0"
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+authors.workspace = true
+edition.workspace = true
+homepage.workspace = true
+repository.workspace = true
+documentation = "https://docs.rs/pezsc-network-light"
+
+[lints]
+workspace = true
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+array-bytes = { workspace = true, default-features = true }
+async-channel = { workspace = true }
+codec = { features = ["derive"], workspace = true, default-features = true }
+futures = { workspace = true }
+log = { workspace = true, default-features = true }
+prost = { workspace = true }
+pezsc-client-api = { workspace = true, default-features = true }
+pezsc-network = { workspace = true, default-features = true }
+pezsc-network-types = { workspace = true, default-features = true }
+pezsp-blockchain = { workspace = true, default-features = true }
+pezsp-core = { workspace = true, default-features = true }
+pezsp-runtime = { workspace = true, default-features = true }
+thiserror = { workspace = true }
+
+[build-dependencies]
+prost-build = { workspace = true }
+
+[features]
+runtime-benchmarks = [
+	"pezsc-client-api/runtime-benchmarks",
+	"pezsc-network/runtime-benchmarks",
+	"pezsp-blockchain/runtime-benchmarks",
+	"pezsp-runtime/runtime-benchmarks",
+]

bizinikiwi/client/network/light/build.rs

@@ -0,0 +1,23 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+const PROTOS: &[&str] = &["src/schema/light.v1.proto"];
+
+fn main() {
+	prost_build::compile_protos(PROTOS, &["src/schema"]).unwrap();
+}

bizinikiwi/client/network/light/src/lib.rs

@@ -0,0 +1,22 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Light client data structures of the networking layer.
+
+pub mod light_client_requests;
+mod schema;

bizinikiwi/client/network/light/src/light_client_requests.rs

@@ -0,0 +1,66 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Helpers for outgoing and incoming light client requests.
+
+use pezsc_network::{
+	config::ProtocolId, request_responses::IncomingRequest, NetworkBackend, MAX_RESPONSE_SIZE,
+};
+use pezsp_runtime::traits::Block;
+
+use std::time::Duration;
+
+/// For incoming light client requests.
+pub mod handler;
+
+/// Generate the light client protocol name from the genesis hash and fork id.
+fn generate_protocol_name<Hash: AsRef<[u8]>>(genesis_hash: Hash, fork_id: Option<&str>) -> String {
+	let genesis_hash = genesis_hash.as_ref();
+	if let Some(fork_id) = fork_id {
+		format!("/{}/{}/light/2", array_bytes::bytes2hex("", genesis_hash), fork_id)
+	} else {
+		format!("/{}/light/2", array_bytes::bytes2hex("", genesis_hash))
+	}
+}
+
+/// Generate the legacy light client protocol name from chain specific protocol identifier.
+fn generate_legacy_protocol_name(protocol_id: &ProtocolId) -> String {
+	format!("/{}/light/2", protocol_id.as_ref())
+}
+
+/// Generates a `RequestResponseProtocolConfig` for the light client request protocol, refusing
+/// incoming requests.
+pub fn generate_protocol_config<
+	Hash: AsRef<[u8]>,
+	B: Block,
+	N: NetworkBackend<B, <B as Block>::Hash>,
+>(
+	protocol_id: &ProtocolId,
+	genesis_hash: Hash,
+	fork_id: Option<&str>,
+	inbound_queue: async_channel::Sender<IncomingRequest>,
+) -> N::RequestResponseProtocolConfig {
+	N::request_response_config(
+		generate_protocol_name(genesis_hash, fork_id).into(),
+		std::iter::once(generate_legacy_protocol_name(protocol_id).into()).collect(),
+		1 * 1024 * 1024,
+		MAX_RESPONSE_SIZE,
+		Duration::from_secs(15),
+		Some(inbound_queue),
+	)
+}

bizinikiwi/client/network/light/src/light_client_requests/handler.rs

@@ -0,0 +1,313 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Helper for incoming light client requests.
+//!
+//! Handle (i.e. answer) incoming light client requests from a remote peer received via
+//! `crate::request_responses::RequestResponsesBehaviour` with
+//! [`LightClientRequestHandler`](handler::LightClientRequestHandler).
+
+use crate::schema;
+use codec::{self, Decode, Encode};
+use futures::prelude::*;
+use log::{debug, trace};
+use prost::Message;
+use pezsc_client_api::{BlockBackend, ProofProvider};
+use pezsc_network::{
+	config::ProtocolId,
+	request_responses::{IncomingRequest, OutgoingResponse},
+	NetworkBackend, ReputationChange,
+};
+use pezsc_network_types::PeerId;
+use pezsp_core::{
+	hexdisplay::HexDisplay,
+	storage::{ChildInfo, ChildType, PrefixedStorageKey},
+};
+use pezsp_runtime::traits::Block;
+use std::{marker::PhantomData, sync::Arc};
+
+const LOG_TARGET: &str = "light-client-request-handler";
+
+/// Incoming requests bounded queue size. For now due to lack of data on light client request
+/// handling in production systems, this value is chosen to match the block request limit.
+const MAX_LIGHT_REQUEST_QUEUE: usize = 20;
+
+/// Handler for incoming light client requests from a remote peer.
+pub struct LightClientRequestHandler<B, Client> {
+	request_receiver: async_channel::Receiver<IncomingRequest>,
+	/// Blockchain client.
+	client: Arc<Client>,
+	_block: PhantomData<B>,
+}
+
+impl<B, Client> LightClientRequestHandler<B, Client>
+where
+	B: Block,
+	Client: BlockBackend<B> + ProofProvider<B> + Send + Sync + 'static,
+{
+	/// Create a new [`LightClientRequestHandler`].
+	pub fn new<N: NetworkBackend<B, <B as Block>::Hash>>(
+		protocol_id: &ProtocolId,
+		fork_id: Option<&str>,
+		client: Arc<Client>,
+	) -> (Self, N::RequestResponseProtocolConfig) {
+		let (tx, request_receiver) = async_channel::bounded(MAX_LIGHT_REQUEST_QUEUE);
+
+		let protocol_config = super::generate_protocol_config::<_, B, N>(
+			protocol_id,
+			client
+				.block_hash(0u32.into())
+				.ok()
+				.flatten()
+				.expect("Genesis block exists; qed"),
+			fork_id,
+			tx,
+		);
+
+		(Self { client, request_receiver, _block: PhantomData::default() }, protocol_config)
+	}
+
+	/// Run [`LightClientRequestHandler`].
+	pub async fn run(mut self) {
+		while let Some(request) = self.request_receiver.next().await {
+			let IncomingRequest { peer, payload, pending_response } = request;
+
+			match self.handle_request(peer, payload) {
+				Ok(response_data) => {
+					let response = OutgoingResponse {
+						result: Ok(response_data),
+						reputation_changes: Vec::new(),
+						sent_feedback: None,
+					};
+
+					match pending_response.send(response) {
+						Ok(()) => trace!(
+							target: LOG_TARGET,
+							"Handled light client request from {}.",
+							peer,
+						),
+						Err(_) => debug!(
+							target: LOG_TARGET,
+							"Failed to handle light client request from {}: {}",
+							peer,
+							HandleRequestError::SendResponse,
+						),
+					};
+				},
+				Err(e) => {
+					debug!(
+						target: LOG_TARGET,
+						"Failed to handle light client request from {}: {}", peer, e,
+					);
+
+					let reputation_changes = match e {
+						HandleRequestError::BadRequest(_) => {
+							vec![ReputationChange::new(-(1 << 12), "bad request")]
+						},
+						_ => Vec::new(),
+					};
+
+					let response = OutgoingResponse {
+						result: Err(()),
+						reputation_changes,
+						sent_feedback: None,
+					};
+
+					if pending_response.send(response).is_err() {
+						debug!(
+							target: LOG_TARGET,
+							"Failed to handle light client request from {}: {}",
+							peer,
+							HandleRequestError::SendResponse,
+						);
+					};
+				},
+			}
+		}
+	}
+
+	fn handle_request(
+		&mut self,
+		peer: PeerId,
+		payload: Vec<u8>,
+	) -> Result<Vec<u8>, HandleRequestError> {
+		let request = schema::v1::light::Request::decode(&payload[..])?;
+
+		let response = match &request.request {
+			Some(schema::v1::light::request::Request::RemoteCallRequest(r)) =>
+				self.on_remote_call_request(&peer, r)?,
+			Some(schema::v1::light::request::Request::RemoteReadRequest(r)) =>
+				self.on_remote_read_request(&peer, r)?,
+			Some(schema::v1::light::request::Request::RemoteReadChildRequest(r)) =>
+				self.on_remote_read_child_request(&peer, r)?,
+			None =>
+				return Err(HandleRequestError::BadRequest("Remote request without request data.")),
+		};
+
+		let mut data = Vec::new();
+		response.encode(&mut data)?;
+
+		Ok(data)
+	}
+
+	fn on_remote_call_request(
+		&mut self,
+		peer: &PeerId,
+		request: &schema::v1::light::RemoteCallRequest,
+	) -> Result<schema::v1::light::Response, HandleRequestError> {
+		trace!("Remote call request from {} ({} at {:?}).", peer, request.method, request.block,);
+
+		let block = Decode::decode(&mut request.block.as_ref())?;
+
+		let response = match self.client.execution_proof(block, &request.method, &request.data) {
+			Ok((_, proof)) => schema::v1::light::RemoteCallResponse { proof: Some(proof.encode()) },
+			Err(e) => {
+				trace!(
+					"remote call request from {} ({} at {:?}) failed with: {}",
+					peer,
+					request.method,
+					request.block,
+					e,
+				);
+				schema::v1::light::RemoteCallResponse { proof: None }
+			},
+		};
+
+		Ok(schema::v1::light::Response {
+			response: Some(schema::v1::light::response::Response::RemoteCallResponse(response)),
+		})
+	}
+
+	fn on_remote_read_request(
+		&mut self,
+		peer: &PeerId,
+		request: &schema::v1::light::RemoteReadRequest,
+	) -> Result<schema::v1::light::Response, HandleRequestError> {
+		if request.keys.is_empty() {
+			debug!("Invalid remote read request sent by {}.", peer);
+			return Err(HandleRequestError::BadRequest("Remote read request without keys."));
+		}
+
+		trace!(
+			"Remote read request from {} ({} at {:?}).",
+			peer,
+			fmt_keys(request.keys.first(), request.keys.last()),
+			request.block,
+		);
+
+		let block = Decode::decode(&mut request.block.as_ref())?;
+
+		let response =
+			match self.client.read_proof(block, &mut request.keys.iter().map(AsRef::as_ref)) {
+				Ok(proof) => schema::v1::light::RemoteReadResponse { proof: Some(proof.encode()) },
+				Err(error) => {
+					trace!(
+						"remote read request from {} ({} at {:?}) failed with: {}",
+						peer,
+						fmt_keys(request.keys.first(), request.keys.last()),
+						request.block,
+						error,
+					);
+					schema::v1::light::RemoteReadResponse { proof: None }
+				},
+			};
+
+		Ok(schema::v1::light::Response {
+			response: Some(schema::v1::light::response::Response::RemoteReadResponse(response)),
+		})
+	}
+
+	fn on_remote_read_child_request(
+		&mut self,
+		peer: &PeerId,
+		request: &schema::v1::light::RemoteReadChildRequest,
+	) -> Result<schema::v1::light::Response, HandleRequestError> {
+		if request.keys.is_empty() {
+			debug!("Invalid remote child read request sent by {}.", peer);
+			return Err(HandleRequestError::BadRequest("Remove read child request without keys."));
+		}
+
+		trace!(
+			"Remote read child request from {} ({} {} at {:?}).",
+			peer,
+			HexDisplay::from(&request.storage_key),
+			fmt_keys(request.keys.first(), request.keys.last()),
+			request.block,
+		);
+
+		let block = Decode::decode(&mut request.block.as_ref())?;
+
+		let prefixed_key = PrefixedStorageKey::new_ref(&request.storage_key);
+		let child_info = match ChildType::from_prefixed_key(prefixed_key) {
+			Some((ChildType::ParentKeyId, storage_key)) => Ok(ChildInfo::new_default(storage_key)),
+			None => Err(pezsp_blockchain::Error::InvalidChildStorageKey),
+		};
+		let response = match child_info.and_then(|child_info| {
+			self.client.read_child_proof(
+				block,
+				&child_info,
+				&mut request.keys.iter().map(AsRef::as_ref),
+			)
+		}) {
+			Ok(proof) => schema::v1::light::RemoteReadResponse { proof: Some(proof.encode()) },
+			Err(error) => {
+				trace!(
+					"remote read child request from {} ({} {} at {:?}) failed with: {}",
+					peer,
+					HexDisplay::from(&request.storage_key),
+					fmt_keys(request.keys.first(), request.keys.last()),
+					request.block,
+					error,
+				);
+				schema::v1::light::RemoteReadResponse { proof: None }
+			},
+		};
+
+		Ok(schema::v1::light::Response {
+			response: Some(schema::v1::light::response::Response::RemoteReadResponse(response)),
+		})
+	}
+}
+
+#[derive(Debug, thiserror::Error)]
+enum HandleRequestError {
+	#[error("Failed to decode request: {0}.")]
+	DecodeProto(#[from] prost::DecodeError),
+	#[error("Failed to encode response: {0}.")]
+	EncodeProto(#[from] prost::EncodeError),
+	#[error("Failed to send response.")]
+	SendResponse,
+	/// A bad request has been received.
+	#[error("bad request: {0}")]
+	BadRequest(&'static str),
+	/// Encoding or decoding of some data failed.
+	#[error("codec error: {0}")]
+	Codec(#[from] codec::Error),
+}
+
+fn fmt_keys(first: Option<&Vec<u8>>, last: Option<&Vec<u8>>) -> String {
+	if let (Some(first), Some(last)) = (first, last) {
+		if first == last {
+			HexDisplay::from(first).to_string()
+		} else {
+			format!("{}..{}", HexDisplay::from(first), HexDisplay::from(last))
+		}
+	} else {
+		String::from("n/a")
+	}
+}

bizinikiwi/client/network/light/src/schema.rs

@@ -0,0 +1,69 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Include sources generated from protobuf definitions.
+
+pub(crate) mod v1 {
+	pub(crate) mod light {
+		include!(concat!(env!("OUT_DIR"), "/api.v1.light.rs"));
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use prost::Message as _;
+
+	#[test]
+	fn empty_proof_encodes_correctly() {
+		let encoded = super::v1::light::Response {
+			response: Some(super::v1::light::response::Response::RemoteReadResponse(
+				super::v1::light::RemoteReadResponse { proof: Some(Vec::new()) },
+			)),
+		}
+		.encode_to_vec();
+
+		// Make sure that the response contains one field of number 2 and wire type 2 (message),
+		// then another field of number 2 and wire type 2 (bytes), then a length of 0.
+		assert_eq!(encoded, vec![(2 << 3) | 2, 2, (2 << 3) | 2, 0]);
+	}
+
+	#[test]
+	fn no_proof_encodes_correctly() {
+		let encoded = super::v1::light::Response {
+			response: Some(super::v1::light::response::Response::RemoteReadResponse(
+				super::v1::light::RemoteReadResponse { proof: None },
+			)),
+		}
+		.encode_to_vec();
+
+		// Make sure that the response contains one field of number 2 and wire type 2 (message).
+		assert_eq!(encoded, vec![(2 << 3) | 2, 0]);
+	}
+
+	#[test]
+	fn proof_encodes_correctly() {
+		let encoded = super::v1::light::Response {
+			response: Some(super::v1::light::response::Response::RemoteReadResponse(
+				super::v1::light::RemoteReadResponse { proof: Some(vec![1, 2, 3, 4]) },
+			)),
+		}
+		.encode_to_vec();
+
+		assert_eq!(encoded, vec![(2 << 3) | 2, 6, (2 << 3) | 2, 4, 1, 2, 3, 4]);
+	}
+}

bizinikiwi/client/network/light/src/schema/light.v1.proto

@@ -0,0 +1,67 @@
+// Schema definition for light client messages.
+
+syntax = "proto2";
+
+package api.v1.light;
+
+// Enumerate all possible light client request messages.
+message Request {
+	oneof request {
+		RemoteCallRequest remote_call_request = 1;
+		RemoteReadRequest remote_read_request = 2;
+		RemoteReadChildRequest remote_read_child_request = 4;
+		// Note: ids 3 and 5 were used in the past. It would be preferable to not re-use them.
+	}
+}
+
+// Enumerate all possible light client response messages.
+message Response {
+	oneof response {
+		RemoteCallResponse remote_call_response = 1;
+		RemoteReadResponse remote_read_response = 2;
+		// Note: ids 3 and 4 were used in the past. It would be preferable to not re-use them.
+	}
+}
+
+// Remote call request.
+message RemoteCallRequest {
+	// Block at which to perform call.
+	required bytes block = 2;
+	// Method name.
+	required string method = 3;
+	// Call data.
+	required bytes data = 4;
+}
+
+// Remote call response.
+message RemoteCallResponse {
+	// Execution proof. If missing, indicates that the remote couldn't answer, for example because
+	// the block is pruned.
+	optional bytes proof = 2;
+}
+
+// Remote storage read request.
+message RemoteReadRequest {
+	// Block at which to perform call.
+	required bytes block = 2;
+	// Storage keys.
+	repeated bytes keys = 3;
+}
+
+// Remote read response.
+message RemoteReadResponse {
+	// Read proof. If missing, indicates that the remote couldn't answer, for example because
+	// the block is pruned.
+	optional bytes proof = 2;
+}
+
+// Remote storage read child request.
+message RemoteReadChildRequest {
+	// Block at which to perform call.
+	required bytes block = 2;
+	// Child Storage key, this is relative
+	// to the child type storage location.
+	required bytes storage_key = 3;
+	// Storage keys.
+	repeated bytes keys = 6;
+}

bizinikiwi/client/network/src/behaviour.rs

@@ -0,0 +1,451 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::{
+	discovery::{DiscoveryBehaviour, DiscoveryConfig, DiscoveryOut},
+	event::DhtEvent,
+	peer_info,
+	peer_store::PeerStoreProvider,
+	protocol::{CustomMessageOutcome, NotificationsSink, Protocol},
+	protocol_controller::SetId,
+	request_responses::{self, IfDisconnected, ProtocolConfig, RequestFailure},
+	service::traits::Direction,
+	types::ProtocolName,
+	ReputationChange,
+};
+
+use futures::channel::oneshot;
+use libp2p::{
+	connection_limits::ConnectionLimits,
+	core::Multiaddr,
+	identify::Info as IdentifyInfo,
+	identity::PublicKey,
+	kad::{Record, RecordKey},
+	swarm::NetworkBehaviour,
+	PeerId, StreamProtocol,
+};
+
+use parking_lot::Mutex;
+use pezsp_runtime::traits::Block as BlockT;
+use std::{
+	collections::HashSet,
+	sync::Arc,
+	time::{Duration, Instant},
+};
+
+pub use crate::request_responses::{InboundFailure, OutboundFailure, ResponseFailure};
+
+/// General behaviour of the network. Combines all protocols together.
+#[derive(NetworkBehaviour)]
+#[behaviour(to_swarm = "BehaviourOut")]
+pub struct Behaviour<B: BlockT> {
+	/// Connection limits.
+	connection_limits: libp2p::connection_limits::Behaviour,
+	/// All the bizinikiwi-specific protocols.
+	bizinikiwi: Protocol<B>,
+	/// Periodically pings and identifies the nodes we are connected to, and store information in a
+	/// cache.
+	peer_info: peer_info::PeerInfoBehaviour,
+	/// Discovers nodes of the network.
+	discovery: DiscoveryBehaviour,
+	/// Generic request-response protocols.
+	request_responses: request_responses::RequestResponsesBehaviour,
+}
+
+/// Event generated by `Behaviour`.
+#[derive(Debug)]
+pub enum BehaviourOut {
+	/// Started a random iterative Kademlia discovery query.
+	RandomKademliaStarted,
+
+	/// We have received a request from a peer and answered it.
+	///
+	/// This event is generated for statistics purposes.
+	InboundRequest {
+		/// Protocol name of the request.
+		protocol: ProtocolName,
+		/// If `Ok`, contains the time elapsed between when we received the request and when we
+		/// sent back the response. If `Err`, the error that happened.
+		result: Result<Duration, ResponseFailure>,
+	},
+
+	/// A request has succeeded or failed.
+	///
+	/// This event is generated for statistics purposes.
+	RequestFinished {
+		/// Name of the protocol in question.
+		protocol: ProtocolName,
+		/// Duration the request took.
+		duration: Duration,
+		/// Result of the request.
+		result: Result<(), RequestFailure>,
+	},
+
+	/// A request protocol handler issued reputation changes for the given peer.
+	ReputationChanges { peer: PeerId, changes: Vec<ReputationChange> },
+
+	/// Opened a substream with the given node with the given notifications protocol.
+	///
+	/// The protocol is always one of the notification protocols that have been registered.
+	NotificationStreamOpened {
+		/// Node we opened the substream with.
+		remote: PeerId,
+		/// Set ID.
+		set_id: SetId,
+		/// Direction of the stream.
+		direction: Direction,
+		/// If the negotiation didn't use the main name of the protocol (the one in
+		/// `notifications_protocol`), then this field contains which name has actually been
+		/// used.
+		/// See also [`crate::Event::NotificationStreamOpened`].
+		negotiated_fallback: Option<ProtocolName>,
+		/// Object that permits sending notifications to the peer.
+		notifications_sink: NotificationsSink,
+		/// Received handshake.
+		received_handshake: Vec<u8>,
+	},
+
+	/// The [`NotificationsSink`] object used to send notifications with the given peer must be
+	/// replaced with a new one.
+	///
+	/// This event is typically emitted when a transport-level connection is closed and we fall
+	/// back to a secondary connection.
+	NotificationStreamReplaced {
+		/// Id of the peer we are connected to.
+		remote: PeerId,
+		/// Set ID.
+		set_id: SetId,
+		/// Replacement for the previous [`NotificationsSink`].
+		notifications_sink: NotificationsSink,
+	},
+
+	/// Closed a substream with the given node. Always matches a corresponding previous
+	/// `NotificationStreamOpened` message.
+	NotificationStreamClosed {
+		/// Node we closed the substream with.
+		remote: PeerId,
+		/// Set ID.
+		set_id: SetId,
+	},
+
+	/// Received one or more messages from the given node using the given protocol.
+	NotificationsReceived {
+		/// Node we received the message from.
+		remote: PeerId,
+		/// Set ID.
+		set_id: SetId,
+		/// Concerned protocol and associated message.
+		notification: Vec<u8>,
+	},
+
+	/// We have obtained identity information from a peer, including the addresses it is listening
+	/// on.
+	PeerIdentify {
+		/// Id of the peer that has been identified.
+		peer_id: PeerId,
+		/// Information about the peer.
+		info: IdentifyInfo,
+	},
+
+	/// We have learned about the existence of a node on the default set.
+	Discovered(PeerId),
+
+	/// Events generated by a DHT as a response to get_value or put_value requests with the
+	/// request duration. Or events generated by the DHT as a consequnce of receiving a record
+	/// to store from peers.
+	Dht(DhtEvent, Option<Duration>),
+
+	/// Ignored event generated by lower layers.
+	None,
+}
+
+impl<B: BlockT> Behaviour<B> {
+	/// Builds a new `Behaviour`.
+	pub fn new(
+		bizinikiwi: Protocol<B>,
+		user_agent: String,
+		local_public_key: PublicKey,
+		disco_config: DiscoveryConfig,
+		request_response_protocols: Vec<ProtocolConfig>,
+		peer_store_handle: Arc<dyn PeerStoreProvider>,
+		external_addresses: Arc<Mutex<HashSet<Multiaddr>>>,
+		public_addresses: Vec<Multiaddr>,
+		connection_limits: ConnectionLimits,
+	) -> Result<Self, request_responses::RegisterError> {
+		Ok(Self {
+			bizinikiwi,
+			peer_info: peer_info::PeerInfoBehaviour::new(
+				user_agent,
+				local_public_key,
+				external_addresses,
+				public_addresses,
+			),
+			discovery: disco_config.finish(),
+			request_responses: request_responses::RequestResponsesBehaviour::new(
+				request_response_protocols.into_iter(),
+				peer_store_handle,
+			)?,
+			connection_limits: libp2p::connection_limits::Behaviour::new(connection_limits),
+		})
+	}
+
+	/// Returns the list of nodes that we know exist in the network.
+	pub fn known_peers(&mut self) -> HashSet<PeerId> {
+		self.discovery.known_peers()
+	}
+
+	/// Adds a hard-coded address for the given peer, that never expires.
+	pub fn add_known_address(&mut self, peer_id: PeerId, addr: Multiaddr) {
+		self.discovery.add_known_address(peer_id, addr)
+	}
+
+	/// Returns the number of nodes in each Kademlia kbucket.
+	///
+	/// Identifies kbuckets by the base 2 logarithm of their lower bound.
+	pub fn num_entries_per_kbucket(&mut self) -> Option<Vec<(u32, usize)>> {
+		self.discovery.num_entries_per_kbucket()
+	}
+
+	/// Returns the number of records in the Kademlia record stores.
+	pub fn num_kademlia_records(&mut self) -> Option<usize> {
+		self.discovery.num_kademlia_records()
+	}
+
+	/// Returns the total size in bytes of all the records in the Kademlia record stores.
+	pub fn kademlia_records_total_size(&mut self) -> Option<usize> {
+		self.discovery.kademlia_records_total_size()
+	}
+
+	/// Borrows `self` and returns a struct giving access to the information about a node.
+	///
+	/// Returns `None` if we don't know anything about this node. Always returns `Some` for nodes
+	/// we're connected to, meaning that if `None` is returned then we're not connected to that
+	/// node.
+	pub fn node(&self, peer_id: &PeerId) -> Option<peer_info::Node<'_>> {
+		self.peer_info.node(peer_id)
+	}
+
+	/// Initiates sending a request.
+	pub fn send_request(
+		&mut self,
+		target: &PeerId,
+		protocol: ProtocolName,
+		request: Vec<u8>,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+		pending_response: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+		connect: IfDisconnected,
+	) {
+		self.request_responses.send_request(
+			target,
+			protocol,
+			request,
+			fallback_request,
+			pending_response,
+			connect,
+		)
+	}
+
+	/// Returns a shared reference to the user protocol.
+	pub fn user_protocol(&self) -> &Protocol<B> {
+		&self.bizinikiwi
+	}
+
+	/// Returns a mutable reference to the user protocol.
+	pub fn user_protocol_mut(&mut self) -> &mut Protocol<B> {
+		&mut self.bizinikiwi
+	}
+
+	/// Add a self-reported address of a remote peer to the k-buckets of the supported
+	/// DHTs (`supported_protocols`).
+	pub fn add_self_reported_address_to_dht(
+		&mut self,
+		peer_id: &PeerId,
+		supported_protocols: &[StreamProtocol],
+		addr: Multiaddr,
+	) {
+		self.discovery.add_self_reported_address(peer_id, supported_protocols, addr);
+	}
+
+	/// Start finding closest peerst to the target `PeerId`. Will later produce either a
+	/// `ClosestPeersFound` or `ClosestPeersNotFound` event.
+	pub fn find_closest_peers(&mut self, target: PeerId) {
+		self.discovery.find_closest_peers(target);
+	}
+
+	/// Start querying a record from the DHT. Will later produce either a `ValueFound` or a
+	/// `ValueNotFound` event.
+	pub fn get_value(&mut self, key: RecordKey) {
+		self.discovery.get_value(key);
+	}
+
+	/// Starts putting a record into DHT. Will later produce either a `ValuePut` or a
+	/// `ValuePutFailed` event.
+	pub fn put_value(&mut self, key: RecordKey, value: Vec<u8>) {
+		self.discovery.put_value(key, value);
+	}
+
+	/// Puts a record into DHT, on the provided Peers
+	pub fn put_record_to(
+		&mut self,
+		record: Record,
+		peers: HashSet<pezsc_network_types::PeerId>,
+		update_local_storage: bool,
+	) {
+		self.discovery.put_record_to(record, peers, update_local_storage);
+	}
+
+	/// Stores value in DHT
+	pub fn store_record(
+		&mut self,
+		record_key: RecordKey,
+		record_value: Vec<u8>,
+		publisher: Option<PeerId>,
+		expires: Option<Instant>,
+	) {
+		self.discovery.store_record(record_key, record_value, publisher, expires);
+	}
+
+	/// Start providing `key` on the DHT.
+	pub fn start_providing(&mut self, key: RecordKey) {
+		self.discovery.start_providing(key)
+	}
+
+	/// Stop providing `key` on the DHT.
+	pub fn stop_providing(&mut self, key: &RecordKey) {
+		self.discovery.stop_providing(key)
+	}
+
+	/// Start searching for providers on the DHT. Will later produce either a `ProvidersFound`
+	/// or `ProvidersNotFound` event.
+	pub fn get_providers(&mut self, key: RecordKey) {
+		self.discovery.get_providers(key)
+	}
+}
+
+impl From<CustomMessageOutcome> for BehaviourOut {
+	fn from(event: CustomMessageOutcome) -> Self {
+		match event {
+			CustomMessageOutcome::NotificationStreamOpened {
+				remote,
+				set_id,
+				direction,
+				negotiated_fallback,
+				received_handshake,
+				notifications_sink,
+			} => BehaviourOut::NotificationStreamOpened {
+				remote,
+				set_id,
+				direction,
+				negotiated_fallback,
+				received_handshake,
+				notifications_sink,
+			},
+			CustomMessageOutcome::NotificationStreamReplaced {
+				remote,
+				set_id,
+				notifications_sink,
+			} => BehaviourOut::NotificationStreamReplaced { remote, set_id, notifications_sink },
+			CustomMessageOutcome::NotificationStreamClosed { remote, set_id } =>
+				BehaviourOut::NotificationStreamClosed { remote, set_id },
+			CustomMessageOutcome::NotificationsReceived { remote, set_id, notification } =>
+				BehaviourOut::NotificationsReceived { remote, set_id, notification },
+		}
+	}
+}
+
+impl From<request_responses::Event> for BehaviourOut {
+	fn from(event: request_responses::Event) -> Self {
+		match event {
+			request_responses::Event::InboundRequest { protocol, result, .. } =>
+				BehaviourOut::InboundRequest { protocol, result },
+			request_responses::Event::RequestFinished { protocol, duration, result, .. } =>
+				BehaviourOut::RequestFinished { protocol, duration, result },
+			request_responses::Event::ReputationChanges { peer, changes } =>
+				BehaviourOut::ReputationChanges { peer, changes },
+		}
+	}
+}
+
+impl From<peer_info::PeerInfoEvent> for BehaviourOut {
+	fn from(event: peer_info::PeerInfoEvent) -> Self {
+		let peer_info::PeerInfoEvent::Identified { peer_id, info } = event;
+		BehaviourOut::PeerIdentify { peer_id, info }
+	}
+}
+
+impl From<DiscoveryOut> for BehaviourOut {
+	fn from(event: DiscoveryOut) -> Self {
+		match event {
+			DiscoveryOut::UnroutablePeer(_peer_id) => {
+				// Obtaining and reporting listen addresses for unroutable peers back
+				// to Kademlia is handled by the `Identify` protocol, part of the
+				// `PeerInfoBehaviour`. See the `From<peer_info::PeerInfoEvent>`
+				// implementation.
+				BehaviourOut::None
+			},
+			DiscoveryOut::Discovered(peer_id) => BehaviourOut::Discovered(peer_id),
+			DiscoveryOut::ClosestPeersFound(target, peers, duration) => BehaviourOut::Dht(
+				DhtEvent::ClosestPeersFound(
+					target.into(),
+					peers
+						.into_iter()
+						.map(|(p, addrs)| (p.into(), addrs.into_iter().map(Into::into).collect()))
+						.collect(),
+				),
+				Some(duration),
+			),
+			DiscoveryOut::ClosestPeersNotFound(target, duration) =>
+				BehaviourOut::Dht(DhtEvent::ClosestPeersNotFound(target.into()), Some(duration)),
+			DiscoveryOut::ValueFound(results, duration) =>
+				BehaviourOut::Dht(DhtEvent::ValueFound(results.into()), Some(duration)),
+			DiscoveryOut::ValueNotFound(key, duration) =>
+				BehaviourOut::Dht(DhtEvent::ValueNotFound(key.into()), Some(duration)),
+			DiscoveryOut::ValuePut(key, duration) =>
+				BehaviourOut::Dht(DhtEvent::ValuePut(key.into()), Some(duration)),
+			DiscoveryOut::PutRecordRequest(record_key, record_value, publisher, expires) =>
+				BehaviourOut::Dht(
+					DhtEvent::PutRecordRequest(record_key.into(), record_value, publisher, expires),
+					None,
+				),
+			DiscoveryOut::ValuePutFailed(key, duration) =>
+				BehaviourOut::Dht(DhtEvent::ValuePutFailed(key.into()), Some(duration)),
+			DiscoveryOut::StartedProviding(key, duration) =>
+				BehaviourOut::Dht(DhtEvent::StartedProviding(key.into()), Some(duration)),
+			DiscoveryOut::StartProvidingFailed(key, duration) =>
+				BehaviourOut::Dht(DhtEvent::StartProvidingFailed(key.into()), Some(duration)),
+			DiscoveryOut::ProvidersFound(key, providers, duration) => BehaviourOut::Dht(
+				DhtEvent::ProvidersFound(
+					key.into(),
+					providers.into_iter().map(Into::into).collect(),
+				),
+				Some(duration),
+			),
+			DiscoveryOut::NoMoreProviders(key, duration) =>
+				BehaviourOut::Dht(DhtEvent::NoMoreProviders(key.into()), Some(duration)),
+			DiscoveryOut::ProvidersNotFound(key, duration) =>
+				BehaviourOut::Dht(DhtEvent::ProvidersNotFound(key.into()), Some(duration)),
+			DiscoveryOut::RandomKademliaStarted => BehaviourOut::RandomKademliaStarted,
+		}
+	}
+}
+
+impl From<void::Void> for BehaviourOut {
+	fn from(e: void::Void) -> Self {
+		void::unreachable(e)
+	}
+}

bizinikiwi/client/network/src/bitswap/mod.rs

@@ -0,0 +1,534 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Bizinikiwi.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// Bizinikiwi is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Bizinikiwi is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Bizinikiwi. If not, see <https://www.gnu.org/licenses/>.
+
+//! Bitswap server for Bizinikiwi.
+//!
+//! Allows querying transactions by hash over standard bitswap protocol
+//! Only supports bitswap 1.2.0.
+//! CID is expected to reference 256-bit Blake2b transaction hash.
+
+use crate::{
+	request_responses::{IncomingRequest, OutgoingResponse, ProtocolConfig},
+	types::ProtocolName,
+	MAX_RESPONSE_SIZE,
+};
+
+use cid::{self, Version};
+use futures::StreamExt;
+use log::{debug, error, trace};
+use prost::Message;
+use pezsc_client_api::BlockBackend;
+use pezsc_network_types::PeerId;
+use schema::bitswap::{
+	message::{wantlist::WantType, Block as MessageBlock, BlockPresence, BlockPresenceType},
+	Message as BitswapMessage,
+};
+use pezsp_runtime::traits::Block as BlockT;
+use std::{io, sync::Arc, time::Duration};
+use unsigned_varint::encode as varint_encode;
+
+mod schema;
+
+const LOG_TARGET: &str = "bitswap";
+
+// Undocumented, but according to JS the bitswap messages have a max size of 512*1024 bytes
+// https://github.com/ipfs/js-ipfs-bitswap/blob/
+// d8f80408aadab94c962f6b88f343eb9f39fa0fcc/src/decision-engine/index.js#L16
+// We set it to the same value as max bizinikiwi protocol message
+const MAX_PACKET_SIZE: u64 = MAX_RESPONSE_SIZE;
+
+/// Max number of queued responses before denying requests.
+const MAX_REQUEST_QUEUE: usize = 20;
+
+/// Max number of blocks per wantlist
+const MAX_WANTED_BLOCKS: usize = 16;
+
+/// Bitswap protocol name
+const PROTOCOL_NAME: &'static str = "/ipfs/bitswap/1.2.0";
+
+/// Prefix represents all metadata of a CID, without the actual content.
+#[derive(PartialEq, Eq, Clone, Debug)]
+struct Prefix {
+	/// The version of CID.
+	pub version: Version,
+	/// The codec of CID.
+	pub codec: u64,
+	/// The multihash type of CID.
+	pub mh_type: u64,
+	/// The multihash length of CID.
+	pub mh_len: u8,
+}
+
+impl Prefix {
+	/// Convert the prefix to encoded bytes.
+	pub fn to_bytes(&self) -> Vec<u8> {
+		let mut res = Vec::with_capacity(4);
+		let mut buf = varint_encode::u64_buffer();
+		let version = varint_encode::u64(self.version.into(), &mut buf);
+		res.extend_from_slice(version);
+		let mut buf = varint_encode::u64_buffer();
+		let codec = varint_encode::u64(self.codec, &mut buf);
+		res.extend_from_slice(codec);
+		let mut buf = varint_encode::u64_buffer();
+		let mh_type = varint_encode::u64(self.mh_type, &mut buf);
+		res.extend_from_slice(mh_type);
+		let mut buf = varint_encode::u64_buffer();
+		let mh_len = varint_encode::u64(self.mh_len as u64, &mut buf);
+		res.extend_from_slice(mh_len);
+		res
+	}
+}
+
+/// Bitswap request handler
+pub struct BitswapRequestHandler<B> {
+	client: Arc<dyn BlockBackend<B> + Send + Sync>,
+	request_receiver: async_channel::Receiver<IncomingRequest>,
+}
+
+impl<B: BlockT> BitswapRequestHandler<B> {
+	/// Create a new [`BitswapRequestHandler`].
+	pub fn new(client: Arc<dyn BlockBackend<B> + Send + Sync>) -> (Self, ProtocolConfig) {
+		let (tx, request_receiver) = async_channel::bounded(MAX_REQUEST_QUEUE);
+
+		let config = ProtocolConfig {
+			name: ProtocolName::from(PROTOCOL_NAME),
+			fallback_names: vec![],
+			max_request_size: MAX_PACKET_SIZE,
+			max_response_size: MAX_PACKET_SIZE,
+			request_timeout: Duration::from_secs(15),
+			inbound_queue: Some(tx),
+		};
+
+		(Self { client, request_receiver }, config)
+	}
+
+	/// Run [`BitswapRequestHandler`].
+	pub async fn run(mut self) {
+		while let Some(request) = self.request_receiver.next().await {
+			let IncomingRequest { peer, payload, pending_response } = request;
+
+			match self.handle_message(&peer, &payload) {
+				Ok(response) => {
+					let response = OutgoingResponse {
+						result: Ok(response),
+						reputation_changes: Vec::new(),
+						sent_feedback: None,
+					};
+
+					match pending_response.send(response) {
+						Ok(()) => {
+							trace!(target: LOG_TARGET, "Handled bitswap request from {peer}.",)
+						},
+						Err(_) => debug!(
+							target: LOG_TARGET,
+							"Failed to handle light client request from {peer}: {}",
+							BitswapError::SendResponse,
+						),
+					}
+				},
+				Err(err) => {
+					error!(target: LOG_TARGET, "Failed to process request from {peer}: {err}");
+
+					// TODO: adjust reputation?
+
+					let response = OutgoingResponse {
+						result: Err(()),
+						reputation_changes: vec![],
+						sent_feedback: None,
+					};
+
+					if pending_response.send(response).is_err() {
+						debug!(
+							target: LOG_TARGET,
+							"Failed to handle bitswap request from {peer}: {}",
+							BitswapError::SendResponse,
+						);
+					}
+				},
+			}
+		}
+	}
+
+	/// Handle received Bitswap request
+	fn handle_message(
+		&mut self,
+		peer: &PeerId,
+		payload: &Vec<u8>,
+	) -> Result<Vec<u8>, BitswapError> {
+		let request = schema::bitswap::Message::decode(&payload[..])?;
+
+		trace!(target: LOG_TARGET, "Received request: {:?} from {}", request, peer);
+
+		let mut response = BitswapMessage::default();
+
+		let wantlist = match request.wantlist {
+			Some(wantlist) => wantlist,
+			None => {
+				debug!(target: LOG_TARGET, "Unexpected bitswap message from {}", peer);
+				return Err(BitswapError::InvalidWantList);
+			},
+		};
+
+		if wantlist.entries.len() > MAX_WANTED_BLOCKS {
+			trace!(target: LOG_TARGET, "Ignored request: too many entries");
+			return Err(BitswapError::TooManyEntries);
+		}
+
+		for entry in wantlist.entries {
+			let cid = match cid::Cid::read_bytes(entry.block.as_slice()) {
+				Ok(cid) => cid,
+				Err(e) => {
+					trace!(target: LOG_TARGET, "Bad CID {:?}: {:?}", entry.block, e);
+					continue;
+				},
+			};
+
+			if cid.version() != cid::Version::V1 ||
+				cid.hash().code() != u64::from(cid::multihash::Code::Blake2b256) ||
+				cid.hash().size() != 32
+			{
+				debug!(target: LOG_TARGET, "Ignoring unsupported CID {}: {}", peer, cid);
+				continue;
+			}
+
+			let mut hash = B::Hash::default();
+			hash.as_mut().copy_from_slice(&cid.hash().digest()[0..32]);
+			let transaction = match self.client.indexed_transaction(hash) {
+				Ok(ex) => ex,
+				Err(e) => {
+					error!(target: LOG_TARGET, "Error retrieving transaction {}: {}", hash, e);
+					None
+				},
+			};
+
+			match transaction {
+				Some(transaction) => {
+					trace!(target: LOG_TARGET, "Found CID {:?}, hash {:?}", cid, hash);
+
+					if entry.want_type == WantType::Block as i32 {
+						let prefix = Prefix {
+							version: cid.version(),
+							codec: cid.codec(),
+							mh_type: cid.hash().code(),
+							mh_len: cid.hash().size(),
+						};
+						response
+							.payload
+							.push(MessageBlock { prefix: prefix.to_bytes(), data: transaction });
+					} else {
+						response.block_presences.push(BlockPresence {
+							r#type: BlockPresenceType::Have as i32,
+							cid: cid.to_bytes(),
+						});
+					}
+				},
+				None => {
+					trace!(target: LOG_TARGET, "Missing CID {:?}, hash {:?}", cid, hash);
+
+					if entry.send_dont_have {
+						response.block_presences.push(BlockPresence {
+							r#type: BlockPresenceType::DontHave as i32,
+							cid: cid.to_bytes(),
+						});
+					}
+				},
+			}
+		}
+
+		Ok(response.encode_to_vec())
+	}
+}
+
+/// Bitswap protocol error.
+#[derive(Debug, thiserror::Error)]
+pub enum BitswapError {
+	/// Protobuf decoding error.
+	#[error("Failed to decode request: {0}.")]
+	DecodeProto(#[from] prost::DecodeError),
+
+	/// Protobuf encoding error.
+	#[error("Failed to encode response: {0}.")]
+	EncodeProto(#[from] prost::EncodeError),
+
+	/// Client backend error.
+	#[error(transparent)]
+	Client(#[from] pezsp_blockchain::Error),
+
+	/// Error parsing CID
+	#[error(transparent)]
+	BadCid(#[from] cid::Error),
+
+	/// Packet read error.
+	#[error(transparent)]
+	Read(#[from] io::Error),
+
+	/// Error sending response.
+	#[error("Failed to send response.")]
+	SendResponse,
+
+	/// Message doesn't have a WANT list.
+	#[error("Invalid WANT list.")]
+	InvalidWantList,
+
+	/// Too many blocks requested.
+	#[error("Too many block entries in the request.")]
+	TooManyEntries,
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use futures::channel::oneshot;
+	use pezsc_block_builder::BlockBuilderBuilder;
+	use schema::bitswap::{
+		message::{wantlist::Entry, Wantlist},
+		Message as BitswapMessage,
+	};
+	use pezsp_consensus::BlockOrigin;
+	use pezsp_runtime::codec::Encode;
+	use bizinikiwi_test_runtime::ExtrinsicBuilder;
+	use bizinikiwi_test_runtime_client::{self, prelude::*, TestClientBuilder};
+
+	#[tokio::test]
+	async fn undecodable_message() {
+		let client = bizinikiwi_test_runtime_client::new();
+		let (bitswap, config) = BitswapRequestHandler::new(Arc::new(client));
+
+		tokio::spawn(async move { bitswap.run().await });
+
+		let (tx, rx) = oneshot::channel();
+		config
+			.inbound_queue
+			.unwrap()
+			.send(IncomingRequest {
+				peer: PeerId::random(),
+				payload: vec![0x13, 0x37, 0x13, 0x38],
+				pending_response: tx,
+			})
+			.await
+			.unwrap();
+
+		if let Ok(OutgoingResponse { result, reputation_changes, sent_feedback }) = rx.await {
+			assert_eq!(result, Err(()));
+			assert_eq!(reputation_changes, Vec::new());
+			assert!(sent_feedback.is_none());
+		} else {
+			panic!("invalid event received");
+		}
+	}
+
+	#[tokio::test]
+	async fn empty_want_list() {
+		let client = bizinikiwi_test_runtime_client::new();
+		let (bitswap, mut config) = BitswapRequestHandler::new(Arc::new(client));
+
+		tokio::spawn(async move { bitswap.run().await });
+
+		let (tx, rx) = oneshot::channel();
+		config
+			.inbound_queue
+			.as_mut()
+			.unwrap()
+			.send(IncomingRequest {
+				peer: PeerId::random(),
+				payload: BitswapMessage { wantlist: None, ..Default::default() }.encode_to_vec(),
+				pending_response: tx,
+			})
+			.await
+			.unwrap();
+
+		if let Ok(OutgoingResponse { result, reputation_changes, sent_feedback }) = rx.await {
+			assert_eq!(result, Err(()));
+			assert_eq!(reputation_changes, Vec::new());
+			assert!(sent_feedback.is_none());
+		} else {
+			panic!("invalid event received");
+		}
+
+		// Empty WANT list should not cause an error
+		let (tx, rx) = oneshot::channel();
+		config
+			.inbound_queue
+			.unwrap()
+			.send(IncomingRequest {
+				peer: PeerId::random(),
+				payload: BitswapMessage {
+					wantlist: Some(Default::default()),
+					..Default::default()
+				}
+				.encode_to_vec(),
+				pending_response: tx,
+			})
+			.await
+			.unwrap();
+
+		if let Ok(OutgoingResponse { result, reputation_changes, sent_feedback }) = rx.await {
+			assert_eq!(result, Ok(BitswapMessage::default().encode_to_vec()));
+			assert_eq!(reputation_changes, Vec::new());
+			assert!(sent_feedback.is_none());
+		} else {
+			panic!("invalid event received");
+		}
+	}
+
+	#[tokio::test]
+	async fn too_long_want_list() {
+		let client = bizinikiwi_test_runtime_client::new();
+		let (bitswap, config) = BitswapRequestHandler::new(Arc::new(client));
+
+		tokio::spawn(async move { bitswap.run().await });
+
+		let (tx, rx) = oneshot::channel();
+		config
+			.inbound_queue
+			.unwrap()
+			.send(IncomingRequest {
+				peer: PeerId::random(),
+				payload: BitswapMessage {
+					wantlist: Some(Wantlist {
+						entries: (0..MAX_WANTED_BLOCKS + 1)
+							.map(|_| Entry::default())
+							.collect::<Vec<_>>(),
+						full: false,
+					}),
+					..Default::default()
+				}
+				.encode_to_vec(),
+				pending_response: tx,
+			})
+			.await
+			.unwrap();
+
+		if let Ok(OutgoingResponse { result, reputation_changes, sent_feedback }) = rx.await {
+			assert_eq!(result, Err(()));
+			assert_eq!(reputation_changes, Vec::new());
+			assert!(sent_feedback.is_none());
+		} else {
+			panic!("invalid event received");
+		}
+	}
+
+	#[tokio::test]
+	async fn transaction_not_found() {
+		let client = TestClientBuilder::with_tx_storage(u32::MAX).build();
+
+		let (bitswap, config) = BitswapRequestHandler::new(Arc::new(client));
+		tokio::spawn(async move { bitswap.run().await });
+
+		let (tx, rx) = oneshot::channel();
+		config
+			.inbound_queue
+			.unwrap()
+			.send(IncomingRequest {
+				peer: PeerId::random(),
+				payload: BitswapMessage {
+					wantlist: Some(Wantlist {
+						entries: vec![Entry {
+							block: cid::Cid::new_v1(
+								0x70,
+								cid::multihash::Multihash::wrap(
+									u64::from(cid::multihash::Code::Blake2b256),
+									&[0u8; 32],
+								)
+								.unwrap(),
+							)
+							.to_bytes(),
+							..Default::default()
+						}],
+						full: false,
+					}),
+					..Default::default()
+				}
+				.encode_to_vec(),
+				pending_response: tx,
+			})
+			.await
+			.unwrap();
+
+		if let Ok(OutgoingResponse { result, reputation_changes, sent_feedback }) = rx.await {
+			assert_eq!(result, Ok(vec![]));
+			assert_eq!(reputation_changes, Vec::new());
+			assert!(sent_feedback.is_none());
+		} else {
+			panic!("invalid event received");
+		}
+	}
+
+	#[tokio::test]
+	async fn transaction_found() {
+		let client = TestClientBuilder::with_tx_storage(u32::MAX).build();
+		let mut block_builder = BlockBuilderBuilder::new(&client)
+			.on_parent_block(client.chain_info().genesis_hash)
+			.with_parent_block_number(0)
+			.build()
+			.unwrap();
+
+		// encoded extrinsic: [161, .. , 2, 6, 16, 19, 55, 19, 56]
+		let ext = ExtrinsicBuilder::new_indexed_call(vec![0x13, 0x37, 0x13, 0x38]).build();
+		let pattern_index = ext.encoded_size() - 4;
+
+		block_builder.push(ext.clone()).unwrap();
+		let block = block_builder.build().unwrap().block;
+
+		client.import(BlockOrigin::File, block).await.unwrap();
+
+		let (bitswap, config) = BitswapRequestHandler::new(Arc::new(client));
+
+		tokio::spawn(async move { bitswap.run().await });
+
+		let (tx, rx) = oneshot::channel();
+		config
+			.inbound_queue
+			.unwrap()
+			.send(IncomingRequest {
+				peer: PeerId::random(),
+				payload: BitswapMessage {
+					wantlist: Some(Wantlist {
+						entries: vec![Entry {
+							block: cid::Cid::new_v1(
+								0x70,
+								cid::multihash::Multihash::wrap(
+									u64::from(cid::multihash::Code::Blake2b256),
+									&pezsp_crypto_hashing::blake2_256(&ext.encode()[pattern_index..]),
+								)
+								.unwrap(),
+							)
+							.to_bytes(),
+							..Default::default()
+						}],
+						full: false,
+					}),
+					..Default::default()
+				}
+				.encode_to_vec(),
+				pending_response: tx,
+			})
+			.await
+			.unwrap();
+
+		if let Ok(OutgoingResponse { result, reputation_changes, sent_feedback }) = rx.await {
+			assert_eq!(reputation_changes, Vec::new());
+			assert!(sent_feedback.is_none());
+
+			let response =
+				schema::bitswap::Message::decode(&result.expect("fetch to succeed")[..]).unwrap();
+			assert_eq!(response.payload[0].data, vec![0x13, 0x37, 0x13, 0x38]);
+		} else {
+			panic!("invalid event received");
+		}
+	}
+}

bizinikiwi/client/network/src/bitswap/schema.rs

@@ -0,0 +1,23 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Include sources generated from protobuf definitions.
+
+pub(crate) mod bitswap {
+	include!(concat!(env!("OUT_DIR"), "/bitswap.message.rs"));
+}

bizinikiwi/client/network/src/config.rs

@@ -0,0 +1,997 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Configuration of the networking layer.
+//!
+//! The [`Params`] struct is the struct that must be passed in order to initialize the networking.
+//! See the documentation of [`Params`].
+
+pub use crate::{
+	discovery::DEFAULT_KADEMLIA_REPLICATION_FACTOR,
+	peer_store::PeerStoreProvider,
+	protocol::{notification_service, NotificationsSink, ProtocolHandlePair},
+	request_responses::{
+		IncomingRequest, OutgoingResponse, ProtocolConfig as RequestResponseConfig,
+	},
+	service::{
+		metrics::NotificationMetrics,
+		traits::{NotificationConfig, NotificationService, PeerStore},
+	},
+	types::ProtocolName,
+};
+
+pub use pezsc_network_types::{build_multiaddr, ed25519};
+use pezsc_network_types::{
+	multiaddr::{self, Multiaddr},
+	PeerId,
+};
+
+use crate::service::{ensure_addresses_consistent_with_transport, traits::NetworkBackend};
+use codec::Encode;
+use prometheus_endpoint::Registry;
+use zeroize::Zeroize;
+
+pub use pezsc_network_common::{
+	role::{Role, Roles},
+	sync::SyncMode,
+	ExHashT,
+};
+
+use pezsp_runtime::traits::Block as BlockT;
+
+use std::{
+	error::Error,
+	fmt, fs,
+	future::Future,
+	io::{self, Write},
+	iter,
+	net::Ipv4Addr,
+	num::NonZeroUsize,
+	path::{Path, PathBuf},
+	pin::Pin,
+	str::{self, FromStr},
+	sync::Arc,
+	time::Duration,
+};
+
+/// Default timeout for idle connections of 10 seconds is good enough for most networks.
+/// It doesn't make sense to expose it as a CLI parameter on individual nodes, but customizations
+/// are possible in custom nodes through [`NetworkConfiguration`].
+pub const DEFAULT_IDLE_CONNECTION_TIMEOUT: Duration = Duration::from_secs(10);
+
+/// Maximum number of locally kept Kademlia provider keys.
+///
+/// 10000 keys is enough for a testnet with fast runtime (1-minute epoch) and 13 teyrchains.
+pub const KADEMLIA_MAX_PROVIDER_KEYS: usize = 10000;
+
+/// Time to keep Kademlia content provider records.
+///
+/// 10 h is enough time to keep the teyrchain bootnode record for two 4-hour epochs.
+pub const KADEMLIA_PROVIDER_RECORD_TTL: Duration = Duration::from_secs(10 * 3600);
+
+/// Interval of republishing Kademlia provider records.
+///
+/// 3.5 h means we refresh next epoch provider record 30 minutes before next 4-hour epoch comes.
+pub const KADEMLIA_PROVIDER_REPUBLISH_INTERVAL: Duration = Duration::from_secs(12600);
+
+/// Protocol name prefix, transmitted on the wire for legacy protocol names.
+/// I.e., `dot` in `/hez/sync/2`. Should be unique for each chain. Always UTF-8.
+/// Deprecated in favour of genesis hash & fork ID based protocol names.
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub struct ProtocolId(smallvec::SmallVec<[u8; 6]>);
+
+impl<'a> From<&'a str> for ProtocolId {
+	fn from(bytes: &'a str) -> ProtocolId {
+		Self(bytes.as_bytes().into())
+	}
+}
+
+impl AsRef<str> for ProtocolId {
+	fn as_ref(&self) -> &str {
+		str::from_utf8(&self.0[..])
+			.expect("the only way to build a ProtocolId is through a UTF-8 String; qed")
+	}
+}
+
+impl fmt::Debug for ProtocolId {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		fmt::Debug::fmt(self.as_ref(), f)
+	}
+}
+
+/// Parses a string address and splits it into Multiaddress and PeerId, if
+/// valid.
+///
+/// # Example
+///
+/// ```
+/// # use pezsc_network_types::{multiaddr::Multiaddr, PeerId};
+/// use pezsc_network::config::parse_str_addr;
+/// let (peer_id, addr) = parse_str_addr(
+/// 	"/ip4/198.51.100.19/tcp/30333/p2p/QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV"
+/// ).unwrap();
+/// assert_eq!(peer_id, "QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV".parse::<PeerId>().unwrap().into());
+/// assert_eq!(addr, "/ip4/198.51.100.19/tcp/30333".parse::<Multiaddr>().unwrap());
+/// ```
+pub fn parse_str_addr(addr_str: &str) -> Result<(PeerId, Multiaddr), ParseErr> {
+	let addr: Multiaddr = addr_str.parse()?;
+	parse_addr(addr)
+}
+
+/// Splits a Multiaddress into a Multiaddress and PeerId.
+pub fn parse_addr(mut addr: Multiaddr) -> Result<(PeerId, Multiaddr), ParseErr> {
+	let multihash = match addr.pop() {
+		Some(multiaddr::Protocol::P2p(multihash)) => multihash,
+		_ => return Err(ParseErr::PeerIdMissing),
+	};
+	let peer_id = PeerId::from_multihash(multihash).map_err(|_| ParseErr::InvalidPeerId)?;
+
+	Ok((peer_id, addr))
+}
+
+/// Address of a node, including its identity.
+///
+/// This struct represents a decoded version of a multiaddress that ends with `/p2p/<peerid>`.
+///
+/// # Example
+///
+/// ```
+/// # use pezsc_network_types::{multiaddr::Multiaddr, PeerId};
+/// use pezsc_network::config::MultiaddrWithPeerId;
+/// let addr: MultiaddrWithPeerId =
+/// 	"/ip4/198.51.100.19/tcp/30333/p2p/QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV".parse().unwrap();
+/// assert_eq!(addr.peer_id.to_base58(), "QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV");
+/// assert_eq!(addr.multiaddr.to_string(), "/ip4/198.51.100.19/tcp/30333");
+/// ```
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize, PartialEq)]
+#[serde(try_from = "String", into = "String")]
+pub struct MultiaddrWithPeerId {
+	/// Address of the node.
+	pub multiaddr: Multiaddr,
+	/// Its identity.
+	pub peer_id: PeerId,
+}
+
+impl MultiaddrWithPeerId {
+	/// Concatenates the multiaddress and peer ID into one multiaddress containing both.
+	pub fn concat(&self) -> Multiaddr {
+		let proto = multiaddr::Protocol::P2p(From::from(self.peer_id));
+		self.multiaddr.clone().with(proto)
+	}
+}
+
+impl fmt::Display for MultiaddrWithPeerId {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		fmt::Display::fmt(&self.concat(), f)
+	}
+}
+
+impl FromStr for MultiaddrWithPeerId {
+	type Err = ParseErr;
+
+	fn from_str(s: &str) -> Result<Self, Self::Err> {
+		let (peer_id, multiaddr) = parse_str_addr(s)?;
+		Ok(Self { peer_id, multiaddr })
+	}
+}
+
+impl From<MultiaddrWithPeerId> for String {
+	fn from(ma: MultiaddrWithPeerId) -> String {
+		format!("{}", ma)
+	}
+}
+
+impl TryFrom<String> for MultiaddrWithPeerId {
+	type Error = ParseErr;
+	fn try_from(string: String) -> Result<Self, Self::Error> {
+		string.parse()
+	}
+}
+
+/// Error that can be generated by `parse_str_addr`.
+#[derive(Debug)]
+pub enum ParseErr {
+	/// Error while parsing the multiaddress.
+	MultiaddrParse(multiaddr::ParseError),
+	/// Multihash of the peer ID is invalid.
+	InvalidPeerId,
+	/// The peer ID is missing from the address.
+	PeerIdMissing,
+}
+
+impl fmt::Display for ParseErr {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		match self {
+			Self::MultiaddrParse(err) => write!(f, "{}", err),
+			Self::InvalidPeerId => write!(f, "Peer id at the end of the address is invalid"),
+			Self::PeerIdMissing => write!(f, "Peer id is missing from the address"),
+		}
+	}
+}
+
+impl std::error::Error for ParseErr {
+	fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+		match self {
+			Self::MultiaddrParse(err) => Some(err),
+			Self::InvalidPeerId => None,
+			Self::PeerIdMissing => None,
+		}
+	}
+}
+
+impl From<multiaddr::ParseError> for ParseErr {
+	fn from(err: multiaddr::ParseError) -> ParseErr {
+		Self::MultiaddrParse(err)
+	}
+}
+
+/// Custom handshake for the notification protocol
+#[derive(Debug, Clone)]
+pub struct NotificationHandshake(Vec<u8>);
+
+impl NotificationHandshake {
+	/// Create new `NotificationHandshake` from an object that implements `Encode`
+	pub fn new<H: Encode>(handshake: H) -> Self {
+		Self(handshake.encode())
+	}
+
+	/// Create new `NotificationHandshake` from raw bytes
+	pub fn from_bytes(bytes: Vec<u8>) -> Self {
+		Self(bytes)
+	}
+}
+
+impl std::ops::Deref for NotificationHandshake {
+	type Target = Vec<u8>;
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+/// Configuration for the transport layer.
+#[derive(Clone, Debug)]
+pub enum TransportConfig {
+	/// Normal transport mode.
+	Normal {
+		/// If true, the network will use mDNS to discover other libp2p nodes on the local network
+		/// and connect to them if they support the same chain.
+		enable_mdns: bool,
+
+		/// If true, allow connecting to private IPv4/IPv6 addresses (as defined in
+		/// [RFC1918](https://tools.ietf.org/html/rfc1918)). Irrelevant for addresses that have
+		/// been passed in `::pezsc_network::config::NetworkConfiguration::boot_nodes`.
+		allow_private_ip: bool,
+	},
+
+	/// Only allow connections within the same process.
+	/// Only addresses of the form `/memory/...` will be supported.
+	MemoryOnly,
+}
+
+/// The policy for connections to non-reserved peers.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum NonReservedPeerMode {
+	/// Accept them. This is the default.
+	Accept,
+	/// Deny them.
+	Deny,
+}
+
+impl NonReservedPeerMode {
+	/// Attempt to parse the peer mode from a string.
+	pub fn parse(s: &str) -> Option<Self> {
+		match s {
+			"accept" => Some(Self::Accept),
+			"deny" => Some(Self::Deny),
+			_ => None,
+		}
+	}
+
+	/// If we are in "reserved-only" peer mode.
+	pub fn is_reserved_only(&self) -> bool {
+		matches!(self, NonReservedPeerMode::Deny)
+	}
+}
+
+/// The configuration of a node's secret key, describing the type of key
+/// and how it is obtained. A node's identity keypair is the result of
+/// the evaluation of the node key configuration.
+#[derive(Clone, Debug)]
+pub enum NodeKeyConfig {
+	/// A Ed25519 secret key configuration.
+	Ed25519(Secret<ed25519::SecretKey>),
+}
+
+impl Default for NodeKeyConfig {
+	fn default() -> NodeKeyConfig {
+		Self::Ed25519(Secret::New)
+	}
+}
+
+/// The options for obtaining a Ed25519 secret key.
+pub type Ed25519Secret = Secret<ed25519::SecretKey>;
+
+/// The configuration options for obtaining a secret key `K`.
+#[derive(Clone)]
+pub enum Secret<K> {
+	/// Use the given secret key `K`.
+	Input(K),
+	/// Read the secret key from a file. If the file does not exist,
+	/// it is created with a newly generated secret key `K`. The format
+	/// of the file is determined by `K`:
+	///
+	///   * `ed25519::SecretKey`: An unencoded 32 bytes Ed25519 secret key.
+	File(PathBuf),
+	/// Always generate a new secret key `K`.
+	New,
+}
+
+impl<K> fmt::Debug for Secret<K> {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		match self {
+			Self::Input(_) => f.debug_tuple("Secret::Input").finish(),
+			Self::File(path) => f.debug_tuple("Secret::File").field(path).finish(),
+			Self::New => f.debug_tuple("Secret::New").finish(),
+		}
+	}
+}
+
+impl NodeKeyConfig {
+	/// Evaluate a `NodeKeyConfig` to obtain an identity `Keypair`:
+	///
+	///  * If the secret is configured as input, the corresponding keypair is returned.
+	///
+	///  * If the secret is configured as a file, it is read from that file, if it exists. Otherwise
+	///    a new secret is generated and stored. In either case, the keypair obtained from the
+	///    secret is returned.
+	///
+	///  * If the secret is configured to be new, it is generated and the corresponding keypair is
+	///    returned.
+	pub fn into_keypair(self) -> io::Result<ed25519::Keypair> {
+		use NodeKeyConfig::*;
+		match self {
+			Ed25519(Secret::New) => Ok(ed25519::Keypair::generate()),
+
+			Ed25519(Secret::Input(k)) => Ok(ed25519::Keypair::from(k).into()),
+
+			Ed25519(Secret::File(f)) => get_secret(
+				f,
+				|mut b| match String::from_utf8(b.to_vec()).ok().and_then(|s| {
+					if s.len() == 64 {
+						array_bytes::hex2bytes(&s).ok()
+					} else {
+						None
+					}
+				}) {
+					Some(s) => ed25519::SecretKey::try_from_bytes(s),
+					_ => ed25519::SecretKey::try_from_bytes(&mut b),
+				},
+				ed25519::SecretKey::generate,
+				|b| b.as_ref().to_vec(),
+			)
+			.map(ed25519::Keypair::from),
+		}
+	}
+}
+
+/// Load a secret key from a file, if it exists, or generate a
+/// new secret key and write it to that file. In either case,
+/// the secret key is returned.
+fn get_secret<P, F, G, E, W, K>(file: P, parse: F, generate: G, serialize: W) -> io::Result<K>
+where
+	P: AsRef<Path>,
+	F: for<'r> FnOnce(&'r mut [u8]) -> Result<K, E>,
+	G: FnOnce() -> K,
+	E: Error + Send + Sync + 'static,
+	W: Fn(&K) -> Vec<u8>,
+{
+	std::fs::read(&file)
+		.and_then(|mut sk_bytes| {
+			parse(&mut sk_bytes).map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))
+		})
+		.or_else(|e| {
+			if e.kind() == io::ErrorKind::NotFound {
+				file.as_ref().parent().map_or(Ok(()), fs::create_dir_all)?;
+				let sk = generate();
+				let mut sk_vec = serialize(&sk);
+				write_secret_file(file, &sk_vec)?;
+				sk_vec.zeroize();
+				Ok(sk)
+			} else {
+				Err(e)
+			}
+		})
+}
+
+/// Write secret bytes to a file.
+fn write_secret_file<P>(path: P, sk_bytes: &[u8]) -> io::Result<()>
+where
+	P: AsRef<Path>,
+{
+	let mut file = open_secret_file(&path)?;
+	file.write_all(sk_bytes)
+}
+
+/// Opens a file containing a secret key in write mode.
+#[cfg(unix)]
+fn open_secret_file<P>(path: P) -> io::Result<fs::File>
+where
+	P: AsRef<Path>,
+{
+	use std::os::unix::fs::OpenOptionsExt;
+	fs::OpenOptions::new().write(true).create_new(true).mode(0o600).open(path)
+}
+
+/// Opens a file containing a secret key in write mode.
+#[cfg(not(unix))]
+fn open_secret_file<P>(path: P) -> Result<fs::File, io::Error>
+where
+	P: AsRef<Path>,
+{
+	fs::OpenOptions::new().write(true).create_new(true).open(path)
+}
+
+/// Configuration for a set of nodes.
+#[derive(Clone, Debug)]
+pub struct SetConfig {
+	/// Maximum allowed number of incoming substreams related to this set.
+	pub in_peers: u32,
+
+	/// Number of outgoing substreams related to this set that we're trying to maintain.
+	pub out_peers: u32,
+
+	/// List of reserved node addresses.
+	pub reserved_nodes: Vec<MultiaddrWithPeerId>,
+
+	/// Whether nodes that aren't in [`SetConfig::reserved_nodes`] are accepted or automatically
+	/// refused.
+	pub non_reserved_mode: NonReservedPeerMode,
+}
+
+impl Default for SetConfig {
+	fn default() -> Self {
+		Self {
+			in_peers: 25,
+			out_peers: 75,
+			reserved_nodes: Vec::new(),
+			non_reserved_mode: NonReservedPeerMode::Accept,
+		}
+	}
+}
+
+/// Extension to [`SetConfig`] for sets that aren't the default set.
+///
+/// > **Note**: As new fields might be added in the future, please consider using the `new` method
+/// >			and modifiers instead of creating this struct manually.
+#[derive(Debug)]
+pub struct NonDefaultSetConfig {
+	/// Name of the notifications protocols of this set. A substream on this set will be
+	/// considered established once this protocol is open.
+	///
+	/// > **Note**: This field isn't present for the default set, as this is handled internally
+	/// > by the networking code.
+	protocol_name: ProtocolName,
+
+	/// If the remote reports that it doesn't support the protocol indicated in the
+	/// `notifications_protocol` field, then each of these fallback names will be tried one by
+	/// one.
+	///
+	/// If a fallback is used, it will be reported in
+	/// `pezsc_network::protocol::event::Event::NotificationStreamOpened::negotiated_fallback`
+	fallback_names: Vec<ProtocolName>,
+
+	/// Handshake of the protocol
+	///
+	/// NOTE: Currently custom handshakes are not fully supported. See issue #5685 for more
+	/// details. This field is temporarily used to allow moving the hardcoded block announcement
+	/// protocol out of `protocol.rs`.
+	handshake: Option<NotificationHandshake>,
+
+	/// Maximum allowed size of single notifications.
+	max_notification_size: u64,
+
+	/// Base configuration.
+	set_config: SetConfig,
+
+	/// Notification handle.
+	///
+	/// Notification handle is created during `NonDefaultSetConfig` creation and its other half,
+	/// `Box<dyn NotificationService>` is given to the protocol created the config and
+	/// `ProtocolHandle` is given to `Notifications` when it initializes itself. This handle allows
+	/// `Notifications ` to communicate with the protocol directly without relaying events through
+	/// `sc-network.`
+	protocol_handle_pair: ProtocolHandlePair,
+}
+
+impl NonDefaultSetConfig {
+	/// Creates a new [`NonDefaultSetConfig`]. Zero slots and accepts only reserved nodes.
+	/// Also returns an object which allows the protocol to communicate with `Notifications`.
+	pub fn new(
+		protocol_name: ProtocolName,
+		fallback_names: Vec<ProtocolName>,
+		max_notification_size: u64,
+		handshake: Option<NotificationHandshake>,
+		set_config: SetConfig,
+	) -> (Self, Box<dyn NotificationService>) {
+		let (protocol_handle_pair, notification_service) =
+			notification_service(protocol_name.clone());
+		(
+			Self {
+				protocol_name,
+				max_notification_size,
+				fallback_names,
+				handshake,
+				set_config,
+				protocol_handle_pair,
+			},
+			notification_service,
+		)
+	}
+
+	/// Get reference to protocol name.
+	pub fn protocol_name(&self) -> &ProtocolName {
+		&self.protocol_name
+	}
+
+	/// Get reference to fallback protocol names.
+	pub fn fallback_names(&self) -> impl Iterator<Item = &ProtocolName> {
+		self.fallback_names.iter()
+	}
+
+	/// Get reference to handshake.
+	pub fn handshake(&self) -> &Option<NotificationHandshake> {
+		&self.handshake
+	}
+
+	/// Get maximum notification size.
+	pub fn max_notification_size(&self) -> u64 {
+		self.max_notification_size
+	}
+
+	/// Get reference to `SetConfig`.
+	pub fn set_config(&self) -> &SetConfig {
+		&self.set_config
+	}
+
+	/// Take `ProtocolHandlePair` from `NonDefaultSetConfig`
+	pub fn take_protocol_handle(self) -> ProtocolHandlePair {
+		self.protocol_handle_pair
+	}
+
+	/// Modifies the configuration to allow non-reserved nodes.
+	pub fn allow_non_reserved(&mut self, in_peers: u32, out_peers: u32) {
+		self.set_config.in_peers = in_peers;
+		self.set_config.out_peers = out_peers;
+		self.set_config.non_reserved_mode = NonReservedPeerMode::Accept;
+	}
+
+	/// Add a node to the list of reserved nodes.
+	pub fn add_reserved(&mut self, peer: MultiaddrWithPeerId) {
+		self.set_config.reserved_nodes.push(peer);
+	}
+
+	/// Add a list of protocol names used for backward compatibility.
+	///
+	/// See the explanations in [`NonDefaultSetConfig::fallback_names`].
+	pub fn add_fallback_names(&mut self, fallback_names: Vec<ProtocolName>) {
+		self.fallback_names.extend(fallback_names);
+	}
+}
+
+impl NotificationConfig for NonDefaultSetConfig {
+	fn set_config(&self) -> &SetConfig {
+		&self.set_config
+	}
+
+	/// Get reference to protocol name.
+	fn protocol_name(&self) -> &ProtocolName {
+		&self.protocol_name
+	}
+}
+
+/// Network service configuration.
+#[derive(Clone, Debug)]
+pub struct NetworkConfiguration {
+	/// Directory path to store network-specific configuration. None means nothing will be saved.
+	pub net_config_path: Option<PathBuf>,
+
+	/// Multiaddresses to listen for incoming connections.
+	pub listen_addresses: Vec<Multiaddr>,
+
+	/// Multiaddresses to advertise. Detected automatically if empty.
+	pub public_addresses: Vec<Multiaddr>,
+
+	/// List of initial node addresses
+	pub boot_nodes: Vec<MultiaddrWithPeerId>,
+
+	/// The node key configuration, which determines the node's network identity keypair.
+	pub node_key: NodeKeyConfig,
+
+	/// Configuration for the default set of nodes used for block syncing and transactions.
+	pub default_peers_set: SetConfig,
+
+	/// Number of substreams to reserve for full nodes for block syncing and transactions.
+	/// Any other slot will be dedicated to light nodes.
+	///
+	/// This value is implicitly capped to `default_set.out_peers + default_set.in_peers`.
+	pub default_peers_set_num_full: u32,
+
+	/// Client identifier. Sent over the wire for debugging purposes.
+	pub client_version: String,
+
+	/// Name of the node. Sent over the wire for debugging purposes.
+	pub node_name: String,
+
+	/// Configuration for the transport layer.
+	pub transport: TransportConfig,
+
+	/// Idle connection timeout.
+	///
+	/// Set by default to [`DEFAULT_IDLE_CONNECTION_TIMEOUT`].
+	pub idle_connection_timeout: Duration,
+
+	/// Maximum number of peers to ask the same blocks in parallel.
+	pub max_parallel_downloads: u32,
+
+	/// Maximum number of blocks per request.
+	pub max_blocks_per_request: u32,
+
+	/// Number of peers that need to be connected before warp sync is started.
+	pub min_peers_to_start_warp_sync: Option<usize>,
+
+	/// Initial syncing mode.
+	pub sync_mode: SyncMode,
+
+	/// True if Kademlia random discovery should be enabled.
+	///
+	/// If true, the node will automatically randomly walk the DHT in order to find new peers.
+	pub enable_dht_random_walk: bool,
+
+	/// Should we insert non-global addresses into the DHT?
+	pub allow_non_globals_in_dht: bool,
+
+	/// Require iterative Kademlia DHT queries to use disjoint paths for increased resiliency in
+	/// the presence of potentially adversarial nodes.
+	pub kademlia_disjoint_query_paths: bool,
+
+	/// Kademlia replication factor determines to how many closest peers a record is replicated to.
+	///
+	/// Discovery mechanism requires successful replication to all
+	/// `kademlia_replication_factor` peers to consider record successfully put.
+	pub kademlia_replication_factor: NonZeroUsize,
+
+	/// Enable serving block data over IPFS bitswap.
+	pub ipfs_server: bool,
+
+	/// Networking backend used for P2P communication.
+	pub network_backend: NetworkBackendType,
+}
+
+impl NetworkConfiguration {
+	/// Create new default configuration
+	pub fn new<SN: Into<String>, SV: Into<String>>(
+		node_name: SN,
+		client_version: SV,
+		node_key: NodeKeyConfig,
+		net_config_path: Option<PathBuf>,
+	) -> Self {
+		let default_peers_set = SetConfig::default();
+		Self {
+			net_config_path,
+			listen_addresses: Vec::new(),
+			public_addresses: Vec::new(),
+			boot_nodes: Vec::new(),
+			node_key,
+			default_peers_set_num_full: default_peers_set.in_peers + default_peers_set.out_peers,
+			default_peers_set,
+			client_version: client_version.into(),
+			node_name: node_name.into(),
+			transport: TransportConfig::Normal { enable_mdns: false, allow_private_ip: true },
+			idle_connection_timeout: DEFAULT_IDLE_CONNECTION_TIMEOUT,
+			max_parallel_downloads: 5,
+			max_blocks_per_request: 64,
+			min_peers_to_start_warp_sync: None,
+			sync_mode: SyncMode::Full,
+			enable_dht_random_walk: true,
+			allow_non_globals_in_dht: false,
+			kademlia_disjoint_query_paths: false,
+			kademlia_replication_factor: NonZeroUsize::new(DEFAULT_KADEMLIA_REPLICATION_FACTOR)
+				.expect("value is a constant; constant is non-zero; qed."),
+			ipfs_server: false,
+			network_backend: NetworkBackendType::Litep2p,
+		}
+	}
+
+	/// Create new default configuration for localhost-only connection with random port (useful for
+	/// testing)
+	pub fn new_local() -> NetworkConfiguration {
+		let mut config =
+			NetworkConfiguration::new("test-node", "test-client", Default::default(), None);
+
+		config.listen_addresses =
+			vec![iter::once(multiaddr::Protocol::Ip4(Ipv4Addr::new(127, 0, 0, 1)))
+				.chain(iter::once(multiaddr::Protocol::Tcp(0)))
+				.collect()];
+
+		config.allow_non_globals_in_dht = true;
+		config
+	}
+
+	/// Create new default configuration for localhost-only connection with random port (useful for
+	/// testing)
+	pub fn new_memory() -> NetworkConfiguration {
+		let mut config =
+			NetworkConfiguration::new("test-node", "test-client", Default::default(), None);
+
+		config.listen_addresses =
+			vec![iter::once(multiaddr::Protocol::Ip4(Ipv4Addr::new(127, 0, 0, 1)))
+				.chain(iter::once(multiaddr::Protocol::Tcp(0)))
+				.collect()];
+
+		config.allow_non_globals_in_dht = true;
+		config
+	}
+}
+
+/// Network initialization parameters.
+pub struct Params<Block: BlockT, H: ExHashT, N: NetworkBackend<Block, H>> {
+	/// Assigned role for our node (full, light, ...).
+	pub role: Role,
+
+	/// How to spawn background tasks.
+	pub executor: Box<dyn Fn(Pin<Box<dyn Future<Output = ()> + Send>>) + Send + Sync>,
+
+	/// Network layer configuration.
+	pub network_config: FullNetworkConfiguration<Block, H, N>,
+
+	/// Legacy name of the protocol to use on the wire. Should be different for each chain.
+	pub protocol_id: ProtocolId,
+
+	/// Genesis hash of the chain
+	pub genesis_hash: Block::Hash,
+
+	/// Fork ID to distinguish protocols of different hard forks. Part of the standard protocol
+	/// name on the wire.
+	pub fork_id: Option<String>,
+
+	/// Registry for recording prometheus metrics to.
+	pub metrics_registry: Option<Registry>,
+
+	/// Block announce protocol configuration
+	pub block_announce_config: N::NotificationProtocolConfig,
+
+	/// Bitswap configuration, if the server has been enabled.
+	pub bitswap_config: Option<N::BitswapConfig>,
+
+	/// Notification metrics.
+	pub notification_metrics: NotificationMetrics,
+}
+
+/// Full network configuration.
+pub struct FullNetworkConfiguration<B: BlockT + 'static, H: ExHashT, N: NetworkBackend<B, H>> {
+	/// Installed notification protocols.
+	pub(crate) notification_protocols: Vec<N::NotificationProtocolConfig>,
+
+	/// List of request-response protocols that the node supports.
+	pub(crate) request_response_protocols: Vec<N::RequestResponseProtocolConfig>,
+
+	/// Network configuration.
+	pub network_config: NetworkConfiguration,
+
+	/// [`PeerStore`](crate::peer_store::PeerStore),
+	peer_store: Option<N::PeerStore>,
+
+	/// Handle to [`PeerStore`](crate::peer_store::PeerStore).
+	peer_store_handle: Arc<dyn PeerStoreProvider>,
+
+	/// Registry for recording prometheus metrics to.
+	pub metrics_registry: Option<Registry>,
+}
+
+impl<B: BlockT + 'static, H: ExHashT, N: NetworkBackend<B, H>> FullNetworkConfiguration<B, H, N> {
+	/// Create new [`FullNetworkConfiguration`].
+	pub fn new(network_config: &NetworkConfiguration, metrics_registry: Option<Registry>) -> Self {
+		let bootnodes = network_config.boot_nodes.iter().map(|bootnode| bootnode.peer_id).collect();
+		let peer_store = N::peer_store(bootnodes, metrics_registry.clone());
+		let peer_store_handle = peer_store.handle();
+
+		Self {
+			peer_store: Some(peer_store),
+			peer_store_handle,
+			notification_protocols: Vec::new(),
+			request_response_protocols: Vec::new(),
+			network_config: network_config.clone(),
+			metrics_registry,
+		}
+	}
+
+	/// Add a notification protocol.
+	pub fn add_notification_protocol(&mut self, config: N::NotificationProtocolConfig) {
+		self.notification_protocols.push(config);
+	}
+
+	/// Get reference to installed notification protocols.
+	pub fn notification_protocols(&self) -> &Vec<N::NotificationProtocolConfig> {
+		&self.notification_protocols
+	}
+
+	/// Add a request-response protocol.
+	pub fn add_request_response_protocol(&mut self, config: N::RequestResponseProtocolConfig) {
+		self.request_response_protocols.push(config);
+	}
+
+	/// Get handle to [`PeerStore`].
+	pub fn peer_store_handle(&self) -> Arc<dyn PeerStoreProvider> {
+		Arc::clone(&self.peer_store_handle)
+	}
+
+	/// Take [`PeerStore`].
+	///
+	/// `PeerStore` is created when `FullNetworkConfig` is initialized so that `PeerStoreHandle`s
+	/// can be passed onto notification protocols. `PeerStore` itself should be started only once
+	/// and since technically it's not a libp2p task, it should be started with `SpawnHandle` in
+	/// `builder.rs` instead of using the libp2p/litep2p executor in the networking backend. This
+	/// function consumes `PeerStore` and starts its event loop in the appropriate place.
+	pub fn take_peer_store(&mut self) -> N::PeerStore {
+		self.peer_store
+			.take()
+			.expect("`PeerStore` can only be taken once when it's started; qed")
+	}
+
+	/// Verify addresses are consistent with enabled transports.
+	pub fn sanity_check_addresses(&self) -> Result<(), crate::error::Error> {
+		ensure_addresses_consistent_with_transport(
+			self.network_config.listen_addresses.iter(),
+			&self.network_config.transport,
+		)?;
+		ensure_addresses_consistent_with_transport(
+			self.network_config.boot_nodes.iter().map(|x| &x.multiaddr),
+			&self.network_config.transport,
+		)?;
+		ensure_addresses_consistent_with_transport(
+			self.network_config
+				.default_peers_set
+				.reserved_nodes
+				.iter()
+				.map(|x| &x.multiaddr),
+			&self.network_config.transport,
+		)?;
+
+		for notification_protocol in &self.notification_protocols {
+			ensure_addresses_consistent_with_transport(
+				notification_protocol.set_config().reserved_nodes.iter().map(|x| &x.multiaddr),
+				&self.network_config.transport,
+			)?;
+		}
+		ensure_addresses_consistent_with_transport(
+			self.network_config.public_addresses.iter(),
+			&self.network_config.transport,
+		)?;
+
+		Ok(())
+	}
+
+	/// Check for duplicate bootnodes.
+	pub fn sanity_check_bootnodes(&self) -> Result<(), crate::error::Error> {
+		self.network_config.boot_nodes.iter().try_for_each(|bootnode| {
+			if let Some(other) = self
+				.network_config
+				.boot_nodes
+				.iter()
+				.filter(|o| o.multiaddr == bootnode.multiaddr)
+				.find(|o| o.peer_id != bootnode.peer_id)
+			{
+				Err(crate::error::Error::DuplicateBootnode {
+					address: bootnode.multiaddr.clone().into(),
+					first_id: bootnode.peer_id.into(),
+					second_id: other.peer_id.into(),
+				})
+			} else {
+				Ok(())
+			}
+		})
+	}
+
+	/// Collect all reserved nodes and bootnodes addresses.
+	pub fn known_addresses(&self) -> Vec<(PeerId, Multiaddr)> {
+		let mut addresses: Vec<_> = self
+			.network_config
+			.default_peers_set
+			.reserved_nodes
+			.iter()
+			.map(|reserved| (reserved.peer_id, reserved.multiaddr.clone()))
+			.chain(self.notification_protocols.iter().flat_map(|protocol| {
+				protocol
+					.set_config()
+					.reserved_nodes
+					.iter()
+					.map(|reserved| (reserved.peer_id, reserved.multiaddr.clone()))
+			}))
+			.chain(
+				self.network_config
+					.boot_nodes
+					.iter()
+					.map(|bootnode| (bootnode.peer_id, bootnode.multiaddr.clone())),
+			)
+			.collect();
+
+		// Remove possible duplicates.
+		addresses.sort();
+		addresses.dedup();
+
+		addresses
+	}
+}
+
+/// Network backend type.
+#[derive(Debug, Clone, Default, Copy)]
+pub enum NetworkBackendType {
+	/// Use litep2p for P2P networking.
+	///
+	/// This is the preferred option for Bizinikiwi-based chains.
+	#[default]
+	Litep2p,
+
+	/// Use libp2p for P2P networking.
+	///
+	/// The libp2p is still used for compatibility reasons until the
+	/// ecosystem switches entirely to litep2p. The backend will enter
+	/// a "best-effort" maintenance mode, where only critical issues will
+	/// get fixed. If you are unsure, please use `NetworkBackendType::Litep2p`.
+	Libp2p,
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use tempfile::TempDir;
+
+	fn tempdir_with_prefix(prefix: &str) -> TempDir {
+		tempfile::Builder::new().prefix(prefix).tempdir().unwrap()
+	}
+
+	fn secret_bytes(kp: ed25519::Keypair) -> Vec<u8> {
+		kp.secret().to_bytes().into()
+	}
+
+	#[test]
+	fn test_secret_file() {
+		let tmp = tempdir_with_prefix("x");
+		std::fs::remove_dir(tmp.path()).unwrap(); // should be recreated
+		let file = tmp.path().join("x").to_path_buf();
+		let kp1 = NodeKeyConfig::Ed25519(Secret::File(file.clone())).into_keypair().unwrap();
+		let kp2 = NodeKeyConfig::Ed25519(Secret::File(file.clone())).into_keypair().unwrap();
+		assert!(file.is_file() && secret_bytes(kp1) == secret_bytes(kp2))
+	}
+
+	#[test]
+	fn test_secret_input() {
+		let sk = ed25519::SecretKey::generate();
+		let kp1 = NodeKeyConfig::Ed25519(Secret::Input(sk.clone())).into_keypair().unwrap();
+		let kp2 = NodeKeyConfig::Ed25519(Secret::Input(sk)).into_keypair().unwrap();
+		assert!(secret_bytes(kp1) == secret_bytes(kp2));
+	}
+
+	#[test]
+	fn test_secret_new() {
+		let kp1 = NodeKeyConfig::Ed25519(Secret::New).into_keypair().unwrap();
+		let kp2 = NodeKeyConfig::Ed25519(Secret::New).into_keypair().unwrap();
+		assert!(secret_bytes(kp1) != secret_bytes(kp2));
+	}
+}

bizinikiwi/client/network/src/error.rs

@@ -0,0 +1,90 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Bizinikiwi network possible errors.
+
+use crate::{config::TransportConfig, types::ProtocolName};
+
+use pezsc_network_types::{multiaddr::Multiaddr, PeerId};
+
+use std::fmt;
+
+/// Result type alias for the network.
+pub type Result<T> = std::result::Result<T, Error>;
+
+/// Error type for the network.
+#[derive(thiserror::Error)]
+pub enum Error {
+	/// Io error
+	#[error(transparent)]
+	Io(#[from] std::io::Error),
+
+	/// Client error
+	#[error(transparent)]
+	Client(#[from] Box<pezsp_blockchain::Error>),
+	/// The same bootnode (based on address) is registered with two different peer ids.
+	#[error(
+		"The same bootnode (`{address}`) is registered with two different peer ids: `{first_id}` and `{second_id}`"
+	)]
+	DuplicateBootnode {
+		/// The address of the bootnode.
+		address: Multiaddr,
+		/// The first peer id that was found for the bootnode.
+		first_id: PeerId,
+		/// The second peer id that was found for the bootnode.
+		second_id: PeerId,
+	},
+	/// Prometheus metrics error.
+	#[error(transparent)]
+	Prometheus(#[from] prometheus_endpoint::PrometheusError),
+	/// The network addresses are invalid because they don't match the transport.
+	#[error(
+		"The following addresses are invalid because they don't match the transport: {addresses:?}"
+	)]
+	AddressesForAnotherTransport {
+		/// Transport used.
+		transport: TransportConfig,
+		/// The invalid addresses.
+		addresses: Vec<Multiaddr>,
+	},
+	/// The same request-response protocol has been registered multiple times.
+	#[error("Request-response protocol registered multiple times: {protocol}")]
+	DuplicateRequestResponseProtocol {
+		/// Name of the protocol registered multiple times.
+		protocol: ProtocolName,
+	},
+	/// Peer does not exist.
+	#[error("Peer `{0}` does not exist.")]
+	PeerDoesntExist(PeerId),
+	/// Channel closed.
+	#[error("Channel closed")]
+	ChannelClosed,
+	/// Connection closed.
+	#[error("Connection closed")]
+	ConnectionClosed,
+	/// Litep2p error.
+	#[error("Litep2p error: `{0}`")]
+	Litep2p(litep2p::Error),
+}
+
+// Make `Debug` use the `Display` implementation.
+impl fmt::Debug for Error {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		fmt::Display::fmt(self, f)
+	}
+}

bizinikiwi/client/network/src/event.rs

@@ -0,0 +1,123 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Network event types. These are not the part of the protocol, but rather
+//! events that happen on the network like DHT get/put results received.
+
+use crate::types::ProtocolName;
+
+use bytes::Bytes;
+
+use pezsc_network_common::role::ObservedRole;
+use pezsc_network_types::{
+	kad::{Key, PeerRecord},
+	multiaddr::Multiaddr,
+	PeerId,
+};
+
+/// Events generated by DHT as a response to get_value and put_value requests.
+#[derive(Debug, Clone)]
+#[must_use]
+pub enum DhtEvent {
+	/// Found closest peers to the target `PeerId`. With libp2p also delivers a partial result
+	/// in case the query timed out, because it can contain the target peer's address.
+	ClosestPeersFound(PeerId, Vec<(PeerId, Vec<Multiaddr>)>),
+
+	/// Closest peers to the target `PeerId` has not been found.
+	ClosestPeersNotFound(PeerId),
+
+	/// The value was found.
+	ValueFound(PeerRecord),
+
+	/// The requested record has not been found in the DHT.
+	ValueNotFound(Key),
+
+	/// The record has been successfully inserted into the DHT.
+	ValuePut(Key),
+
+	/// An error has occurred while putting a record into the DHT.
+	ValuePutFailed(Key),
+
+	/// Successfully started providing the given key.
+	StartedProviding(Key),
+
+	/// An error occured while registering as a content provider on the DHT.
+	StartProvidingFailed(Key),
+
+	/// The DHT received a put record request.
+	PutRecordRequest(Key, Vec<u8>, Option<PeerId>, Option<std::time::Instant>),
+
+	/// The providers for [`Key`] were found. Multiple such events can be generated per provider
+	/// discovery request.
+	ProvidersFound(Key, Vec<PeerId>),
+
+	/// `GET_PROVIDERS` query finished and won't yield any more providers.
+	NoMoreProviders(Key),
+
+	/// `GET_PROVIDERS` query failed and no providers for [`Key`] were found. libp2p also emits
+	/// this event after already yielding some results via [`DhtEvent::ProvidersFound`].
+	ProvidersNotFound(Key),
+}
+
+/// Type for events generated by networking layer.
+#[derive(Debug, Clone)]
+#[must_use]
+pub enum Event {
+	/// Event generated by a DHT.
+	Dht(DhtEvent),
+
+	/// Opened a substream with the given node with the given notifications protocol.
+	///
+	/// The protocol is always one of the notification protocols that have been registered.
+	NotificationStreamOpened {
+		/// Node we opened the substream with.
+		remote: PeerId,
+		/// The concerned protocol. Each protocol uses a different substream.
+		/// This is always equal to the value of
+		/// `pezsc_network::config::NonDefaultSetConfig::notifications_protocol` of one of the
+		/// configured sets.
+		protocol: ProtocolName,
+		/// If the negotiation didn't use the main name of the protocol (the one in
+		/// `notifications_protocol`), then this field contains which name has actually been
+		/// used.
+		/// Always contains a value equal to the value in
+		/// `pezsc_network::config::NonDefaultSetConfig::fallback_names`.
+		negotiated_fallback: Option<ProtocolName>,
+		/// Role of the remote.
+		role: ObservedRole,
+		/// Received handshake.
+		received_handshake: Vec<u8>,
+	},
+
+	/// Closed a substream with the given node. Always matches a corresponding previous
+	/// `NotificationStreamOpened` message.
+	NotificationStreamClosed {
+		/// Node we closed the substream with.
+		remote: PeerId,
+		/// The concerned protocol. Each protocol uses a different substream.
+		protocol: ProtocolName,
+	},
+
+	/// Received one or more messages from the given node using the given protocol.
+	NotificationsReceived {
+		/// Node we received the message from.
+		remote: PeerId,
+		/// Concerned protocol and associated message.
+		messages: Vec<(ProtocolName, Bytes)>,
+	},
+}

bizinikiwi/client/network/src/lib.rs

@@ -0,0 +1,310 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+#![warn(unused_extern_crates)]
+#![warn(missing_docs)]
+
+//! Bizinikiwi-specific P2P networking.
+//!
+//! **Important**: This crate is unstable and the API and usage may change.
+//!
+//! # Node identities and addresses
+//!
+//! In a decentralized network, each node possesses a network private key and a network public key.
+//! In Bizinikiwi, the keys are based on the ed25519 curve.
+//!
+//! From a node's public key, we can derive its *identity*. In Bizinikiwi and libp2p, a node's
+//! identity is represented with the [`PeerId`] struct. All network communications between nodes on
+//! the network use encryption derived from both sides's keys, which means that **identities cannot
+//! be faked**.
+//!
+//! A node's identity uniquely identifies a machine on the network. If you start two or more
+//! clients using the same network key, large interferences will happen.
+//!
+//! # Bizinikiwi's network protocol
+//!
+//! Bizinikiwi's networking protocol is based upon libp2p. It is at the moment not possible and not
+//! planned to permit using something else than the libp2p network stack and the rust-libp2p
+//! library. However the libp2p framework is very flexible and the rust-libp2p library could be
+//! extended to support a wider range of protocols than what is offered by libp2p.
+//!
+//! ## Discovery mechanisms
+//!
+//! In order for our node to join a peer-to-peer network, it has to know a list of nodes that are
+//! part of said network. This includes nodes identities and their address (how to reach them).
+//! Building such a list is called the **discovery** mechanism. There are three mechanisms that
+//! Bizinikiwi uses:
+//!
+//! - Bootstrap nodes. These are hard-coded node identities and addresses passed alongside with
+//! the network configuration.
+//! - mDNS. We perform a UDP broadcast on the local network. Nodes that listen may respond with
+//! their identity. More info [here](https://github.com/libp2p/specs/blob/master/discovery/mdns.md).
+//! mDNS can be disabled in the network configuration.
+//! - Kademlia random walk. Once connected, we perform random Kademlia `FIND_NODE` requests on the
+//! configured Kademlia DHTs (one per configured chain protocol) in order for nodes to propagate to
+//! us their view of the network. More information about Kademlia can be found [on
+//! Wikipedia](https://en.wikipedia.org/wiki/Kademlia).
+//!
+//! ## Connection establishment
+//!
+//! When node Alice knows node Bob's identity and address, it can establish a connection with Bob.
+//! All connections must always use encryption and multiplexing. While some node addresses (eg.
+//! addresses using `/quic`) already imply which encryption and/or multiplexing to use, for others
+//! the **multistream-select** protocol is used in order to negotiate an encryption layer and/or a
+//! multiplexing layer.
+//!
+//! The connection establishment mechanism is called the **transport**.
+//!
+//! As of the writing of this documentation, the following base-layer protocols are supported by
+//! Bizinikiwi:
+//!
+//! - TCP/IP for addresses of the form `/ip4/1.2.3.4/tcp/5`. Once the TCP connection is open, an
+//! encryption and a multiplexing layer are negotiated on top.
+//! - WebSockets for addresses of the form `/ip4/1.2.3.4/tcp/5/ws`. A TCP/IP connection is open and
+//! the WebSockets protocol is negotiated on top. Communications then happen inside WebSockets data
+//! frames. Encryption and multiplexing are additionally negotiated again inside this channel.
+//! - DNS for addresses of the form `/dns/example.com/tcp/5` or `/dns/example.com/tcp/5/ws`. A
+//! node's address can contain a domain name.
+//! - (All of the above using IPv6 instead of IPv4.)
+//!
+//! On top of the base-layer protocol, the [Noise](https://noiseprotocol.org/) protocol is
+//! negotiated and applied. The exact handshake protocol is experimental and is subject to change.
+//!
+//! The following multiplexing protocols are supported:
+//!
+//! - [Yamux](https://github.com/hashicorp/yamux/blob/master/spec.md).
+//!
+//! ## Substreams
+//!
+//! Once a connection has been established and uses multiplexing, substreams can be opened. When
+//! a substream is open, the **multistream-select** protocol is used to negotiate which protocol
+//! to use on that given substream.
+//!
+//! Protocols that are specific to a certain chain have a `<protocol-id>` in their name. This
+//! "protocol ID" is defined in the chain specifications. For example, the protocol ID of Pezkuwi
+//! is "hez". In the protocol names below, `<protocol-id>` must be replaced with the corresponding
+//! protocol ID.
+//!
+//! > **Note**: It is possible for the same connection to be used for multiple chains. For example,
+//! > one can use both the `/hez/sync/2` and `/sub/sync/2` protocols on the same
+//! > connection, provided that the remote supports them.
+//!
+//! Bizinikiwi uses the following standard libp2p protocols:
+//!
+//! - **`/ipfs/ping/1.0.0`**. We periodically open an ephemeral substream in order to ping the
+//! remote and check whether the connection is still alive. Failure for the remote to reply leads
+//! to a disconnection.
+//! - **[`/ipfs/id/1.0.0`](https://github.com/libp2p/specs/tree/master/identify)**. We
+//! periodically open an ephemeral substream in order to ask information from the remote.
+//! - **[`/<protocol_id>/kad`](https://github.com/libp2p/specs/pull/108)**. We periodically open
+//! ephemeral substreams for Kademlia random walk queries. Each Kademlia query is done in a
+//! separate substream.
+//!
+//! Additionally, Bizinikiwi uses the following non-libp2p-standard protocols:
+//!
+//! - **`/bizinikiwi/<protocol-id>/<version>`** (where `<protocol-id>` must be replaced with the
+//! protocol ID of the targeted chain, and `<version>` is a number between 2 and 6). For each
+//! connection we optionally keep an additional substream for all Bizinikiwi-based communications
+//! alive. This protocol is considered legacy, and is progressively being replaced with
+//! alternatives. This is designated as "The legacy Bizinikiwi substream" in this documentation. See
+//! below for more details.
+//! - **`/<protocol-id>/sync/2`** is a request-response protocol (see below) that lets one perform
+//! requests for information about blocks. Each request is the encoding of a `BlockRequest` and
+//! each response is the encoding of a `BlockResponse`, as defined in the `api.v1.proto` file in
+//! this source tree.
+//! - **`/<protocol-id>/light/2`** is a request-response protocol (see below) that lets one perform
+//! light-client-related requests for information about the state. Each request is the encoding of
+//! a `light::Request` and each response is the encoding of a `light::Response`, as defined in the
+//! `light.v1.proto` file in this source tree.
+//! - **`/<protocol-id>/transactions/1`** is a notifications protocol (see below) where
+//! transactions are pushed to other nodes. The handshake is empty on both sides. The message
+//! format is a SCALE-encoded list of transactions, where each transaction is an opaque list of
+//! bytes.
+//! - **`/<protocol-id>/block-announces/1`** is a notifications protocol (see below) where
+//! block announces are pushed to other nodes. The handshake is empty on both sides. The message
+//! format is a SCALE-encoded tuple containing a block header followed with an opaque list of
+//! bytes containing some data associated with this block announcement, e.g. a candidate message.
+//! - Notifications protocols that are registered using
+//! `NetworkConfiguration::notifications_protocols`. For example: `/paritytech/grandpa/1`. See
+//! below for more information.
+//!
+//! ## The legacy Bizinikiwi substream
+//!
+//! Bizinikiwi uses a component named the **peerset manager (PSM)**. Through the discovery
+//! mechanism, the PSM is aware of the nodes that are part of the network and decides which nodes
+//! we should perform Bizinikiwi-based communications with. For these nodes, we open a connection
+//! if necessary and open a unique substream for Bizinikiwi-based communications. If the PSM decides
+//! that we should disconnect a node, then that substream is closed.
+//!
+//! For more information about the PSM, see the *sc-peerset* crate.
+//!
+//! Note that at the moment there is no mechanism in place to solve the issues that arise where the
+//! two sides of a connection open the unique substream simultaneously. In order to not run into
+//! issues, only the dialer of a connection is allowed to open the unique substream. When the
+//! substream is closed, the entire connection is closed as well. This is a bug that will be
+//! resolved by deprecating the protocol entirely.
+//!
+//! Within the unique Bizinikiwi substream, messages encoded using
+//! [*parity-scale-codec*](https://github.com/paritytech/parity-scale-codec) are exchanged.
+//! The detail of theses messages is not totally in place, but they can be found in the
+//! `message.rs` file.
+//!
+//! Once the substream is open, the first step is an exchange of a *status* message from both
+//! sides, containing information such as the chain root hash, head of chain, and so on.
+//!
+//! Communications within this substream include:
+//!
+//! - Syncing. Blocks are announced and requested from other nodes.
+//! - Light-client requests. When a light client requires information, a random node we have a
+//! substream open with is chosen, and the information is requested from it.
+//! - Gossiping. Used for example by grandpa.
+//!
+//! ## Request-response protocols
+//!
+//! A so-called request-response protocol is defined as follow:
+//!
+//! - When a substream is opened, the opening side sends a message whose content is
+//! protocol-specific. The message must be prefixed with an
+//! [LEB128-encoded number](https://en.wikipedia.org/wiki/LEB128) indicating its length. After the
+//! message has been sent, the writing side is closed.
+//! - The remote sends back the response prefixed with a LEB128-encoded length, and closes its
+//! side as well.
+//!
+//! Each request is performed in a new separate substream.
+//!
+//! ## Notifications protocols
+//!
+//! A so-called notifications protocol is defined as follow:
+//!
+//! - When a substream is opened, the opening side sends a handshake message whose content is
+//! protocol-specific. The handshake message must be prefixed with an
+//! [LEB128-encoded number](https://en.wikipedia.org/wiki/LEB128) indicating its length. The
+//! handshake message can be of length 0, in which case the sender has to send a single `0`.
+//! - The receiver then either immediately closes the substream, or answers with its own
+//! LEB128-prefixed protocol-specific handshake response. The message can be of length 0, in which
+//! case a single `0` has to be sent back.
+//! - Once the handshake has completed, the notifications protocol is unidirectional. Only the
+//! node which initiated the substream can push notifications. If the remote wants to send
+//! notifications as well, it has to open its own undirectional substream.
+//! - Each notification must be prefixed with an LEB128-encoded length. The encoding of the
+//! messages is specific to each protocol.
+//! - Either party can signal that it doesn't want a notifications substream anymore by closing
+//! its writing side. The other party should respond by closing its own writing side soon after.
+//!
+//! The API of `sc-network` allows one to register user-defined notification protocols.
+//! `sc-network` automatically tries to open a substream towards each node for which the legacy
+//! Substream substream is open. The handshake is then performed automatically.
+//!
+//! For example, the `sc-consensus-grandpa` crate registers the `/paritytech/grandpa/1`
+//! notifications protocol.
+//!
+//! At the moment, for backwards-compatibility, notification protocols are tied to the legacy
+//! Bizinikiwi substream. Additionally, the handshake message is hardcoded to be a single 8-bits
+//! integer representing the role of the node:
+//!
+//! - 1 for a full node.
+//! - 2 for a light node.
+//! - 4 for an authority.
+//!
+//! In the future, though, these restrictions will be removed.
+//!
+//! # Usage
+//!
+//! Using the `sc-network` crate is done through the [`NetworkWorker`] struct. Create this
+//! struct by passing a [`config::Params`], then poll it as if it was a `Future`. You can extract an
+//! `Arc<NetworkService>` from the `NetworkWorker`, which can be shared amongst multiple places
+//! in order to give orders to the networking.
+//!
+//! See the [`config`] module for more information about how to configure the networking.
+//!
+//! After the `NetworkWorker` has been created, the important things to do are:
+//!
+//! - Calling `NetworkWorker::poll` in order to advance the network. This can be done by
+//! dispatching a background task with the [`NetworkWorker`].
+//! - Calling `on_block_import` whenever a block is added to the client.
+//! - Calling `on_block_finalized` whenever a block is finalized.
+//! - Calling `trigger_repropagate` when a transaction is added to the pool.
+//!
+//! More precise usage details are still being worked on and will likely change in the future.
+
+mod behaviour;
+mod bitswap;
+mod litep2p;
+mod protocol;
+
+#[cfg(test)]
+mod mock;
+
+pub mod config;
+pub mod discovery;
+pub mod error;
+pub mod event;
+pub mod network_state;
+pub mod peer_info;
+pub mod peer_store;
+pub mod protocol_controller;
+pub mod request_responses;
+pub mod service;
+pub mod transport;
+pub mod types;
+pub mod utils;
+
+pub use crate::litep2p::Litep2pNetworkBackend;
+pub use event::{DhtEvent, Event};
+#[doc(inline)]
+pub use request_responses::{Config, IfDisconnected, RequestFailure};
+pub use pezsc_network_common::{
+	role::{ObservedRole, Roles},
+	types::ReputationChange,
+};
+pub use pezsc_network_types::{
+	multiaddr::{self, Multiaddr},
+	PeerId,
+};
+pub use service::{
+	metrics::NotificationMetrics,
+	signature::Signature,
+	traits::{
+		KademliaKey, MessageSink, NetworkBackend, NetworkBlock, NetworkDHTProvider,
+		NetworkEventStream, NetworkPeers, NetworkRequest, NetworkSigner, NetworkStateInfo,
+		NetworkStatus, NetworkStatusProvider, NetworkSyncForkRequest, NotificationConfig,
+		NotificationSender as NotificationSenderT, NotificationSenderError,
+		NotificationSenderReady, NotificationService,
+	},
+	DecodingError, Keypair, NetworkService, NetworkWorker, NotificationSender, OutboundFailure,
+	PublicKey,
+};
+pub use types::ProtocolName;
+
+/// Log target for `sc-network`.
+const LOG_TARGET: &str = "sub-libp2p";
+
+/// The maximum allowed number of established connections per peer.
+///
+/// Typically, and by design of the network behaviours in this crate,
+/// there is a single established connection per peer. However, to
+/// avoid unnecessary and nondeterministic connection closure in
+/// case of (possibly repeated) simultaneous dialing attempts between
+/// two peers, the per-peer connection limit is not set to 1 but 2.
+const MAX_CONNECTIONS_PER_PEER: usize = 2;
+
+/// The maximum number of concurrent established connections that were incoming.
+const MAX_CONNECTIONS_ESTABLISHED_INCOMING: u32 = 10_000;
+
+/// Maximum response size limit.
+pub const MAX_RESPONSE_SIZE: u64 = 16 * 1024 * 1024;

bizinikiwi/client/network/src/litep2p/discovery.rs

@@ -0,0 +1,962 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! libp2p-related discovery code for litep2p backend.
+
+use crate::{
+	config::{
+		NetworkConfiguration, ProtocolId, KADEMLIA_MAX_PROVIDER_KEYS, KADEMLIA_PROVIDER_RECORD_TTL,
+		KADEMLIA_PROVIDER_REPUBLISH_INTERVAL,
+	},
+	peer_store::PeerStoreProvider,
+};
+
+use array_bytes::bytes2hex;
+use futures::{FutureExt, Stream};
+use futures_timer::Delay;
+use ip_network::IpNetwork;
+use litep2p::{
+	protocol::{
+		libp2p::{
+			identify::{Config as IdentifyConfig, IdentifyEvent},
+			kademlia::{
+				Config as KademliaConfig, ConfigBuilder as KademliaConfigBuilder, ContentProvider,
+				IncomingRecordValidationMode, KademliaEvent, KademliaHandle, PeerRecord, QueryId,
+				Quorum, Record, RecordKey,
+			},
+			ping::{Config as PingConfig, PingEvent},
+		},
+		mdns::{Config as MdnsConfig, MdnsEvent},
+	},
+	types::multiaddr::{Multiaddr, Protocol},
+	PeerId, ProtocolName,
+};
+use parking_lot::RwLock;
+use pezsc_network_types::kad::Key as KademliaKey;
+use schnellru::{ByLength, LruMap};
+
+use std::{
+	cmp,
+	collections::{HashMap, HashSet, VecDeque},
+	iter,
+	num::NonZeroUsize,
+	pin::Pin,
+	sync::Arc,
+	task::{Context, Poll},
+	time::{Duration, Instant},
+};
+
+/// Logging target for the file.
+const LOG_TARGET: &str = "sub-libp2p::discovery";
+
+/// Kademlia query interval.
+const KADEMLIA_QUERY_INTERVAL: Duration = Duration::from_secs(5);
+
+/// mDNS query interval.
+const MDNS_QUERY_INTERVAL: Duration = Duration::from_secs(30);
+
+/// The minimum number of peers we expect an answer before we terminate the request.
+const GET_RECORD_REDUNDANCY_FACTOR: usize = 4;
+
+/// The maximum number of tracked external addresses we allow.
+const MAX_EXTERNAL_ADDRESSES: u32 = 32;
+
+/// Number of times observed address is received from different peers before it is confirmed as
+/// external.
+const MIN_ADDRESS_CONFIRMATIONS: usize = 3;
+
+/// Quorum threshold to interpret `PUT_VALUE` & `ADD_PROVIDER` as successful.
+///
+/// As opposed to libp2p, litep2p does not finish the query as soon as the required number of
+/// peers have reached. Instead, it tries to put the record to all target peers (typically 20) and
+/// uses the quorum setting only to determine the success of the query.
+///
+/// We set the threshold to 50% of the target peers to account for unreachable peers. The actual
+/// number of stored records may be higher.
+const QUORUM_THRESHOLD: NonZeroUsize = NonZeroUsize::new(10).expect("10 > 0; qed");
+
+/// Discovery events.
+#[derive(Debug)]
+pub enum DiscoveryEvent {
+	/// Ping RTT measured for peer.
+	Ping {
+		/// Remote peer ID.
+		peer: PeerId,
+
+		/// Ping round-trip time.
+		rtt: Duration,
+	},
+
+	/// Peer identified over `/ipfs/identify/1.0.0` protocol.
+	Identified {
+		/// Peer ID.
+		peer: PeerId,
+
+		/// Listen addresses.
+		listen_addresses: Vec<Multiaddr>,
+
+		/// Supported protocols.
+		supported_protocols: HashSet<ProtocolName>,
+	},
+
+	/// One or more addresses discovered.
+	///
+	/// This event is emitted when a new peer is discovered over mDNS.
+	Discovered {
+		/// Discovered addresses.
+		addresses: Vec<Multiaddr>,
+	},
+
+	/// Routing table has been updated.
+	RoutingTableUpdate {
+		/// Peers that were added to routing table.
+		peers: HashSet<PeerId>,
+	},
+
+	/// New external address discovered.
+	ExternalAddressDiscovered {
+		/// Discovered address.
+		address: Multiaddr,
+	},
+
+	/// The external address has expired.
+	///
+	/// This happens when the internal buffers exceed the maximum number of external addresses,
+	/// and this address is the oldest one.
+	ExternalAddressExpired {
+		/// Expired address.
+		address: Multiaddr,
+	},
+
+	/// `FIND_NODE` query succeeded.
+	FindNodeSuccess {
+		/// Query ID.
+		query_id: QueryId,
+
+		/// Target.
+		target: PeerId,
+
+		/// Found peers.
+		peers: Vec<(PeerId, Vec<Multiaddr>)>,
+	},
+
+	/// `GetRecord` query succeeded.
+	GetRecordSuccess {
+		/// Query ID.
+		query_id: QueryId,
+	},
+
+	/// Record was found from the DHT.
+	GetRecordPartialResult {
+		/// Query ID.
+		query_id: QueryId,
+
+		/// Record.
+		record: PeerRecord,
+	},
+
+	/// Record was successfully stored on the DHT.
+	PutRecordSuccess {
+		/// Query ID.
+		query_id: QueryId,
+	},
+
+	/// Providers were successfully retrieved.
+	GetProvidersSuccess {
+		/// Query ID.
+		query_id: QueryId,
+		/// Found providers sorted by distance to provided key.
+		providers: Vec<ContentProvider>,
+	},
+
+	/// Provider was successfully published.
+	AddProviderSuccess {
+		/// Query ID.
+		query_id: QueryId,
+		/// Provided key.
+		provided_key: RecordKey,
+	},
+
+	/// Query failed.
+	QueryFailed {
+		/// Query ID.
+		query_id: QueryId,
+	},
+
+	/// Incoming record to store.
+	IncomingRecord {
+		/// Record.
+		record: Record,
+	},
+
+	/// Started a random Kademlia query.
+	RandomKademliaStarted,
+}
+
+/// Discovery.
+pub struct Discovery {
+	/// Local peer ID.
+	local_peer_id: litep2p::PeerId,
+
+	/// Ping event stream.
+	ping_event_stream: Box<dyn Stream<Item = PingEvent> + Send + Unpin>,
+
+	/// Identify event stream.
+	identify_event_stream: Box<dyn Stream<Item = IdentifyEvent> + Send + Unpin>,
+
+	/// mDNS event stream, if enabled.
+	mdns_event_stream: Option<Box<dyn Stream<Item = MdnsEvent> + Send + Unpin>>,
+
+	/// Kademlia handle.
+	kademlia_handle: KademliaHandle,
+
+	/// `Peerstore` handle.
+	_peerstore_handle: Arc<dyn PeerStoreProvider>,
+
+	/// Next Kademlia query for a random peer ID.
+	///
+	/// If `None`, there is currently a query pending.
+	next_kad_query: Option<Delay>,
+
+	/// Active `FIND_NODE` query if it exists.
+	random_walk_query_id: Option<QueryId>,
+
+	/// Pending events.
+	pending_events: VecDeque<DiscoveryEvent>,
+
+	/// Allow non-global addresses in the DHT.
+	allow_non_global_addresses: bool,
+
+	/// Protocols supported by the local node.
+	local_protocols: HashSet<ProtocolName>,
+
+	/// Public addresses.
+	public_addresses: HashSet<Multiaddr>,
+
+	/// Listen addresses.
+	listen_addresses: Arc<RwLock<HashSet<Multiaddr>>>,
+
+	/// External address confirmations.
+	address_confirmations: LruMap<Multiaddr, HashSet<PeerId>>,
+
+	/// Delay to next `FIND_NODE` query.
+	duration_to_next_find_query: Duration,
+}
+
+/// Legacy (fallback) Kademlia protocol name based on `protocol_id`.
+fn legacy_kademlia_protocol_name(id: &ProtocolId) -> ProtocolName {
+	ProtocolName::from(format!("/{}/kad", id.as_ref()))
+}
+
+/// Kademlia protocol name based on `genesis_hash` and `fork_id`.
+fn kademlia_protocol_name<Hash: AsRef<[u8]>>(
+	genesis_hash: Hash,
+	fork_id: Option<&str>,
+) -> ProtocolName {
+	let genesis_hash_hex = bytes2hex("", genesis_hash.as_ref());
+	let protocol = if let Some(fork_id) = fork_id {
+		format!("/{}/{}/kad", genesis_hash_hex, fork_id)
+	} else {
+		format!("/{}/kad", genesis_hash_hex)
+	};
+
+	ProtocolName::from(protocol)
+}
+
+impl Discovery {
+	/// Create new [`Discovery`].
+	///
+	/// Enables `/ipfs/ping/1.0.0` and `/ipfs/identify/1.0.0` by default and starts
+	/// the mDNS peer discovery if it was enabled.
+	pub fn new<Hash: AsRef<[u8]> + Clone>(
+		local_peer_id: litep2p::PeerId,
+		config: &NetworkConfiguration,
+		genesis_hash: Hash,
+		fork_id: Option<&str>,
+		protocol_id: &ProtocolId,
+		known_peers: HashMap<PeerId, Vec<Multiaddr>>,
+		listen_addresses: Arc<RwLock<HashSet<Multiaddr>>>,
+		_peerstore_handle: Arc<dyn PeerStoreProvider>,
+	) -> (Self, PingConfig, IdentifyConfig, KademliaConfig, Option<MdnsConfig>) {
+		let (ping_config, ping_event_stream) = PingConfig::default();
+		let user_agent = format!("{} ({}) (litep2p)", config.client_version, config.node_name);
+
+		let (identify_config, identify_event_stream) =
+			IdentifyConfig::new("/bizinikiwi/1.0".to_string(), Some(user_agent));
+
+		let (mdns_config, mdns_event_stream) = match config.transport {
+			crate::config::TransportConfig::Normal { enable_mdns, .. } => match enable_mdns {
+				true => {
+					let (mdns_config, mdns_event_stream) = MdnsConfig::new(MDNS_QUERY_INTERVAL);
+					(Some(mdns_config), Some(mdns_event_stream))
+				},
+				false => (None, None),
+			},
+			_ => panic!("memory transport not supported"),
+		};
+
+		let (kademlia_config, kademlia_handle) = {
+			let protocol_names = vec![
+				kademlia_protocol_name(genesis_hash.clone(), fork_id),
+				legacy_kademlia_protocol_name(protocol_id),
+			];
+
+			KademliaConfigBuilder::new()
+				.with_known_peers(known_peers)
+				.with_protocol_names(protocol_names)
+				.with_incoming_records_validation_mode(IncomingRecordValidationMode::Manual)
+				.with_provider_record_ttl(KADEMLIA_PROVIDER_RECORD_TTL)
+				.with_provider_refresh_interval(KADEMLIA_PROVIDER_REPUBLISH_INTERVAL)
+				.with_max_provider_keys(KADEMLIA_MAX_PROVIDER_KEYS)
+				.build()
+		};
+
+		(
+			Self {
+				local_peer_id,
+				ping_event_stream,
+				identify_event_stream,
+				mdns_event_stream,
+				kademlia_handle,
+				_peerstore_handle,
+				listen_addresses,
+				random_walk_query_id: None,
+				pending_events: VecDeque::new(),
+				duration_to_next_find_query: Duration::from_secs(1),
+				address_confirmations: LruMap::new(ByLength::new(MAX_EXTERNAL_ADDRESSES)),
+				allow_non_global_addresses: config.allow_non_globals_in_dht,
+				public_addresses: config.public_addresses.iter().cloned().map(Into::into).collect(),
+				next_kad_query: Some(Delay::new(KADEMLIA_QUERY_INTERVAL)),
+				local_protocols: HashSet::from_iter([kademlia_protocol_name(
+					genesis_hash,
+					fork_id,
+				)]),
+			},
+			ping_config,
+			identify_config,
+			kademlia_config,
+			mdns_config,
+		)
+	}
+
+	/// Add known peer to `Kademlia`.
+	#[allow(unused)]
+	pub async fn add_known_peer(&mut self, peer: PeerId, addresses: Vec<Multiaddr>) {
+		self.kademlia_handle.add_known_peer(peer, addresses).await;
+	}
+
+	/// Add self-reported addresses to routing table if `peer` supports
+	/// at least one of the locally supported DHT protocol.
+	pub async fn add_self_reported_address(
+		&mut self,
+		peer: PeerId,
+		supported_protocols: HashSet<ProtocolName>,
+		addresses: Vec<Multiaddr>,
+	) {
+		if self.local_protocols.is_disjoint(&supported_protocols) {
+			log::trace!(
+				target: LOG_TARGET,
+				"Ignoring self-reported address of peer {peer} as remote node is not part of the \
+				 Kademlia DHT supported by the local node.",
+			);
+			return;
+		}
+
+		let addresses = addresses
+			.into_iter()
+			.filter_map(|address| {
+				if !self.allow_non_global_addresses && !Discovery::can_add_to_dht(&address) {
+					log::trace!(
+						target: LOG_TARGET,
+						"ignoring self-reported non-global address {address} from {peer}."
+					);
+
+					return None;
+				}
+
+				Some(address)
+			})
+			.collect();
+
+		log::trace!(
+			target: LOG_TARGET,
+			"add self-reported addresses for {peer:?}: {addresses:?}",
+		);
+
+		self.kademlia_handle.add_known_peer(peer, addresses).await;
+	}
+
+	/// Start Kademlia `FIND_NODE` query for `target`.
+	pub async fn find_node(&mut self, target: PeerId) -> QueryId {
+		self.kademlia_handle.find_node(target).await
+	}
+
+	/// Start Kademlia `GET_VALUE` query for `key`.
+	pub async fn get_value(&mut self, key: KademliaKey) -> QueryId {
+		self.kademlia_handle
+			.get_record(
+				RecordKey::new(&key.to_vec()),
+				Quorum::N(NonZeroUsize::new(GET_RECORD_REDUNDANCY_FACTOR).unwrap()),
+			)
+			.await
+	}
+
+	/// Publish value on the DHT using Kademlia `PUT_VALUE`.
+	pub async fn put_value(&mut self, key: KademliaKey, value: Vec<u8>) -> QueryId {
+		self.kademlia_handle
+			.put_record(
+				Record::new(RecordKey::new(&key.to_vec()), value),
+				Quorum::N(QUORUM_THRESHOLD),
+			)
+			.await
+	}
+
+	/// Put record to given peers.
+	pub async fn put_value_to_peers(
+		&mut self,
+		record: Record,
+		peers: Vec<pezsc_network_types::PeerId>,
+		update_local_storage: bool,
+	) -> QueryId {
+		self.kademlia_handle
+			.put_record_to_peers(
+				record,
+				peers.into_iter().map(|peer| peer.into()).collect(),
+				update_local_storage,
+				// These are the peers that just returned the record to us in authority-discovery,
+				// so we assume they are all reachable.
+				Quorum::All,
+			)
+			.await
+	}
+
+	/// Store record in the local DHT store.
+	pub async fn store_record(
+		&mut self,
+		key: KademliaKey,
+		value: Vec<u8>,
+		publisher: Option<pezsc_network_types::PeerId>,
+		expires: Option<Instant>,
+	) {
+		log::debug!(
+			target: LOG_TARGET,
+			"Storing DHT record with key {key:?}, originally published by {publisher:?}, \
+			 expires {expires:?}.",
+		);
+
+		self.kademlia_handle
+			.store_record(Record {
+				key: RecordKey::new(&key.to_vec()),
+				value,
+				publisher: publisher.map(Into::into),
+				expires,
+			})
+			.await;
+	}
+
+	/// Start providing `key`.
+	pub async fn start_providing(&mut self, key: KademliaKey) -> QueryId {
+		self.kademlia_handle
+			.start_providing(key.into(), Quorum::N(QUORUM_THRESHOLD))
+			.await
+	}
+
+	/// Stop providing `key`.
+	pub async fn stop_providing(&mut self, key: KademliaKey) {
+		self.kademlia_handle.stop_providing(key.into()).await;
+	}
+
+	/// Get providers for `key`.
+	pub async fn get_providers(&mut self, key: KademliaKey) -> QueryId {
+		self.kademlia_handle.get_providers(key.into()).await
+	}
+
+	/// Check if the observed address is a known address.
+	fn is_known_address(known: &Multiaddr, observed: &Multiaddr) -> bool {
+		let mut known = known.iter();
+		let mut observed = observed.iter();
+
+		loop {
+			match (known.next(), observed.next()) {
+				(None, None) => return true,
+				(None, Some(Protocol::P2p(_))) => return true,
+				(Some(Protocol::P2p(_)), None) => return true,
+				(known, observed) if known != observed => return false,
+				_ => {},
+			}
+		}
+	}
+
+	/// Can `address` be added to DHT.
+	fn can_add_to_dht(address: &Multiaddr) -> bool {
+		let ip = match address.iter().next() {
+			Some(Protocol::Ip4(ip)) => IpNetwork::from(ip),
+			Some(Protocol::Ip6(ip)) => IpNetwork::from(ip),
+			Some(Protocol::Dns(_)) | Some(Protocol::Dns4(_)) | Some(Protocol::Dns6(_)) =>
+				return true,
+			_ => return false,
+		};
+
+		ip.is_global()
+	}
+
+	/// Check if `address` can be considered a new external address.
+	///
+	/// If this address replaces an older address, the expired address is returned.
+	fn is_new_external_address(
+		&mut self,
+		address: &Multiaddr,
+		peer: PeerId,
+	) -> (bool, Option<Multiaddr>) {
+		log::trace!(target: LOG_TARGET, "verify new external address: {address}");
+
+		if !self.allow_non_global_addresses && !Discovery::can_add_to_dht(&address) {
+			log::trace!(
+				target: LOG_TARGET,
+				"ignoring externally reported non-global address {address} from {peer}."
+			);
+
+			return (false, None);
+		}
+
+		// is the address one of our known addresses
+		if self
+			.listen_addresses
+			.read()
+			.iter()
+			.chain(self.public_addresses.iter())
+			.any(|known_address| Discovery::is_known_address(&known_address, &address))
+		{
+			return (true, None);
+		}
+
+		match self.address_confirmations.get(address) {
+			Some(confirmations) => {
+				confirmations.insert(peer);
+
+				if confirmations.len() >= MIN_ADDRESS_CONFIRMATIONS {
+					return (true, None);
+				}
+			},
+			None => {
+				let oldest = (self.address_confirmations.len() >=
+					self.address_confirmations.limiter().max_length() as usize)
+					.then(|| {
+						self.address_confirmations.pop_oldest().map(|(address, peers)| {
+							if peers.len() >= MIN_ADDRESS_CONFIRMATIONS {
+								return Some(address);
+							} else {
+								None
+							}
+						})
+					})
+					.flatten()
+					.flatten();
+
+				self.address_confirmations.insert(address.clone(), iter::once(peer).collect());
+
+				return (false, oldest);
+			},
+		}
+
+		(false, None)
+	}
+}
+
+impl Stream for Discovery {
+	type Item = DiscoveryEvent;
+
+	fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+		let this = Pin::into_inner(self);
+
+		if let Some(event) = this.pending_events.pop_front() {
+			return Poll::Ready(Some(event));
+		}
+
+		if let Some(mut delay) = this.next_kad_query.take() {
+			match delay.poll_unpin(cx) {
+				Poll::Pending => {
+					this.next_kad_query = Some(delay);
+				},
+				Poll::Ready(()) => {
+					let peer = PeerId::random();
+
+					log::trace!(target: LOG_TARGET, "start next kademlia query for {peer:?}");
+
+					match this.kademlia_handle.try_find_node(peer) {
+						Ok(query_id) => {
+							this.random_walk_query_id = Some(query_id);
+							return Poll::Ready(Some(DiscoveryEvent::RandomKademliaStarted));
+						},
+						Err(()) => {
+							this.duration_to_next_find_query = cmp::min(
+								this.duration_to_next_find_query * 2,
+								Duration::from_secs(60),
+							);
+							this.next_kad_query =
+								Some(Delay::new(this.duration_to_next_find_query));
+						},
+					}
+				},
+			}
+		}
+
+		match Pin::new(&mut this.kademlia_handle).poll_next(cx) {
+			Poll::Pending => {},
+			Poll::Ready(None) => return Poll::Ready(None),
+			Poll::Ready(Some(KademliaEvent::FindNodeSuccess { query_id, peers, .. }))
+				if Some(query_id) == this.random_walk_query_id =>
+			{
+				// the addresses are already inserted into the DHT and in `TransportManager` so
+				// there is no need to add them again. The found peers must be registered to
+				// `Peerstore` so other protocols are aware of them through `Peerset`.
+				log::trace!(target: LOG_TARGET, "dht random walk yielded {} peers", peers.len());
+
+				this.next_kad_query = Some(Delay::new(KADEMLIA_QUERY_INTERVAL));
+
+				return Poll::Ready(Some(DiscoveryEvent::RoutingTableUpdate {
+					peers: peers.into_iter().map(|(peer, _)| peer).collect(),
+				}));
+			},
+			Poll::Ready(Some(KademliaEvent::FindNodeSuccess { query_id, target, peers })) => {
+				log::trace!(target: LOG_TARGET, "find node query yielded {} peers", peers.len());
+
+				return Poll::Ready(Some(DiscoveryEvent::FindNodeSuccess {
+					query_id,
+					target,
+					peers,
+				}));
+			},
+			Poll::Ready(Some(KademliaEvent::RoutingTableUpdate { peers })) => {
+				log::trace!(target: LOG_TARGET, "routing table update, discovered {} peers", peers.len());
+
+				return Poll::Ready(Some(DiscoveryEvent::RoutingTableUpdate {
+					peers: peers.into_iter().collect(),
+				}));
+			},
+			Poll::Ready(Some(KademliaEvent::GetRecordSuccess { query_id })) => {
+				log::trace!(
+					target: LOG_TARGET,
+					"`GET_RECORD` succeeded for {query_id:?}",
+				);
+
+				return Poll::Ready(Some(DiscoveryEvent::GetRecordSuccess { query_id }));
+			},
+			Poll::Ready(Some(KademliaEvent::GetRecordPartialResult { query_id, record })) => {
+				log::trace!(
+					target: LOG_TARGET,
+					"`GET_RECORD` intermediary succeeded for {query_id:?}: {record:?}",
+				);
+
+				return Poll::Ready(Some(DiscoveryEvent::GetRecordPartialResult {
+					query_id,
+					record,
+				}));
+			},
+			Poll::Ready(Some(KademliaEvent::PutRecordSuccess { query_id, key: _ })) =>
+				return Poll::Ready(Some(DiscoveryEvent::PutRecordSuccess { query_id })),
+			Poll::Ready(Some(KademliaEvent::QueryFailed { query_id })) => {
+				match this.random_walk_query_id == Some(query_id) {
+					true => {
+						this.random_walk_query_id = None;
+						this.duration_to_next_find_query =
+							cmp::min(this.duration_to_next_find_query * 2, Duration::from_secs(60));
+						this.next_kad_query = Some(Delay::new(this.duration_to_next_find_query));
+					},
+					false => return Poll::Ready(Some(DiscoveryEvent::QueryFailed { query_id })),
+				}
+			},
+			Poll::Ready(Some(KademliaEvent::IncomingRecord { record })) => {
+				log::trace!(
+					target: LOG_TARGET,
+					"incoming `PUT_RECORD` request with key {:?} from publisher {:?}",
+					record.key,
+					record.publisher,
+				);
+
+				return Poll::Ready(Some(DiscoveryEvent::IncomingRecord { record }));
+			},
+			Poll::Ready(Some(KademliaEvent::GetProvidersSuccess {
+				provided_key,
+				providers,
+				query_id,
+			})) => {
+				log::trace!(
+					target: LOG_TARGET,
+					"`GET_PROVIDERS` for {query_id:?} with {provided_key:?} yielded {providers:?}",
+				);
+
+				return Poll::Ready(Some(DiscoveryEvent::GetProvidersSuccess {
+					query_id,
+					providers,
+				}));
+			},
+			Poll::Ready(Some(KademliaEvent::AddProviderSuccess { query_id, provided_key })) => {
+				log::trace!(
+					target: LOG_TARGET,
+					"`ADD_PROVIDER` for {query_id:?} with {provided_key:?} succeeded",
+				);
+
+				return Poll::Ready(Some(DiscoveryEvent::AddProviderSuccess {
+					query_id,
+					provided_key,
+				}));
+			},
+			// We do not validate incoming providers.
+			Poll::Ready(Some(KademliaEvent::IncomingProvider { .. })) => {},
+		}
+
+		match Pin::new(&mut this.identify_event_stream).poll_next(cx) {
+			Poll::Pending => {},
+			Poll::Ready(None) => return Poll::Ready(None),
+			Poll::Ready(Some(IdentifyEvent::PeerIdentified {
+				peer,
+				listen_addresses,
+				supported_protocols,
+				observed_address,
+				..
+			})) => {
+				let observed_address =
+					if let Some(Protocol::P2p(peer_id)) = observed_address.iter().last() {
+						if peer_id != *this.local_peer_id.as_ref() {
+							log::warn!(
+								target: LOG_TARGET,
+								"Discovered external address for a peer that is not us: {observed_address}",
+							);
+							None
+						} else {
+							Some(observed_address)
+						}
+					} else {
+						Some(observed_address.with(Protocol::P2p(this.local_peer_id.into())))
+					};
+
+				// Ensure that an external address with a different peer ID does not have
+				// side effects of evicting other external addresses via `ExternalAddressExpired`.
+				if let Some(observed_address) = observed_address {
+					let (is_new, expired_address) =
+						this.is_new_external_address(&observed_address, peer);
+
+					if let Some(expired_address) = expired_address {
+						log::trace!(
+							target: LOG_TARGET,
+							"Removing expired external address expired={expired_address} is_new={is_new} observed={observed_address}",
+						);
+
+						this.pending_events.push_back(DiscoveryEvent::ExternalAddressExpired {
+							address: expired_address,
+						});
+					}
+
+					if is_new {
+						this.pending_events.push_back(DiscoveryEvent::ExternalAddressDiscovered {
+							address: observed_address.clone(),
+						});
+					}
+				}
+
+				return Poll::Ready(Some(DiscoveryEvent::Identified {
+					peer,
+					listen_addresses,
+					supported_protocols,
+				}));
+			},
+		}
+
+		match Pin::new(&mut this.ping_event_stream).poll_next(cx) {
+			Poll::Pending => {},
+			Poll::Ready(None) => return Poll::Ready(None),
+			Poll::Ready(Some(PingEvent::Ping { peer, ping })) =>
+				return Poll::Ready(Some(DiscoveryEvent::Ping { peer, rtt: ping })),
+		}
+
+		if let Some(ref mut mdns_event_stream) = &mut this.mdns_event_stream {
+			match Pin::new(mdns_event_stream).poll_next(cx) {
+				Poll::Pending => {},
+				Poll::Ready(None) => return Poll::Ready(None),
+				Poll::Ready(Some(MdnsEvent::Discovered(addresses))) =>
+					return Poll::Ready(Some(DiscoveryEvent::Discovered { addresses })),
+			}
+		}
+
+		Poll::Pending
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	use std::sync::atomic::AtomicU32;
+
+	use crate::{
+		config::ProtocolId,
+		peer_store::{PeerStore, PeerStoreProvider},
+	};
+	use futures::{stream::FuturesUnordered, StreamExt};
+	use pezsp_core::H256;
+	use pezsp_tracing::tracing_subscriber;
+
+	use litep2p::{
+		config::ConfigBuilder as Litep2pConfigBuilder, transport::tcp::config::Config as TcpConfig,
+		Litep2p,
+	};
+
+	#[tokio::test]
+	async fn litep2p_discovery_works() {
+		let _ = tracing_subscriber::fmt()
+			.with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
+			.try_init();
+
+		let mut known_peers = HashMap::new();
+		let genesis_hash = H256::from_low_u64_be(1);
+		let fork_id = Some("test-fork-id");
+		let protocol_id = ProtocolId::from("hez");
+
+		// Build backends such that the first peer is known to all other peers.
+		let backends = (0..10)
+			.map(|i| {
+				let keypair = litep2p::crypto::ed25519::Keypair::generate();
+				let peer_id: PeerId = keypair.public().to_peer_id().into();
+
+				let listen_addresses = Arc::new(RwLock::new(HashSet::new()));
+
+				let peer_store = PeerStore::new(vec![], None);
+				let peer_store_handle: Arc<dyn PeerStoreProvider> = Arc::new(peer_store.handle());
+
+				let (discovery, ping_config, identify_config, kademlia_config, _mdns) =
+					Discovery::new(
+						peer_id,
+						&NetworkConfiguration::new_local(),
+						genesis_hash,
+						fork_id,
+						&protocol_id,
+						known_peers.clone(),
+						listen_addresses.clone(),
+						peer_store_handle,
+					);
+
+				let config = Litep2pConfigBuilder::new()
+					.with_keypair(keypair)
+					.with_tcp(TcpConfig {
+						listen_addresses: vec!["/ip6/::1/tcp/0".parse().unwrap()],
+						..Default::default()
+					})
+					.with_libp2p_ping(ping_config)
+					.with_libp2p_identify(identify_config)
+					.with_libp2p_kademlia(kademlia_config)
+					.build();
+
+				let mut litep2p = Litep2p::new(config).unwrap();
+
+				let addresses = litep2p.listen_addresses().cloned().collect::<Vec<_>>();
+				// Propagate addresses to discovery.
+				addresses.iter().for_each(|address| {
+					listen_addresses.write().insert(address.clone());
+				});
+
+				// Except the first peer, all other peers know the first peer addresses.
+				if i == 0 {
+					log::info!(target: LOG_TARGET, "First peer is {peer_id:?} with addresses {addresses:?}");
+					known_peers.insert(peer_id, addresses.clone());
+				} else {
+					let (peer, addresses) = known_peers.iter().next().unwrap();
+
+					let result = litep2p.add_known_address(*peer, addresses.into_iter().cloned());
+
+					log::info!(target: LOG_TARGET, "{peer_id:?}: Adding known peer {peer:?} with addresses {addresses:?} result={result:?}");
+
+				}
+
+				(peer_id, litep2p, discovery)
+			})
+			.collect::<Vec<_>>();
+
+		let total_peers = backends.len() as u32;
+		let remaining_peers =
+			backends.iter().map(|(peer_id, _, _)| *peer_id).collect::<HashSet<_>>();
+
+		let first_peer = *known_peers.iter().next().unwrap().0;
+
+		// Each backend must discover the whole network.
+		let mut futures = FuturesUnordered::new();
+		let num_finished = Arc::new(AtomicU32::new(0));
+
+		for (peer_id, mut litep2p, mut discovery) in backends {
+			// Remove the local peer id from the set.
+			let mut remaining_peers = remaining_peers.clone();
+			remaining_peers.remove(&peer_id);
+
+			let num_finished = num_finished.clone();
+
+			let future = async move {
+				log::info!(target: LOG_TARGET, "{peer_id:?} starting loop");
+
+				if peer_id != first_peer {
+					log::info!(target: LOG_TARGET, "{peer_id:?} dialing {first_peer:?}");
+					litep2p.dial(&first_peer).await.unwrap();
+				}
+
+				loop {
+					// We need to keep the network alive until all peers are discovered.
+					if num_finished.load(std::sync::atomic::Ordering::Relaxed) == total_peers {
+						log::info!(target: LOG_TARGET, "{peer_id:?} all peers discovered");
+						break;
+					}
+
+					tokio::select! {
+						// Drive litep2p backend forward.
+						event = litep2p.next_event() => {
+							log::info!(target: LOG_TARGET, "{peer_id:?} Litep2p event: {event:?}");
+						},
+
+						// Detect discovery events.
+						event = discovery.next() => {
+							match event.unwrap() {
+								// We have discovered the peer via kademlia and established
+								// a connection on the identify protocol.
+								DiscoveryEvent::Identified { peer, .. } => {
+									log::info!(target: LOG_TARGET, "{peer_id:?} Peer {peer} identified");
+
+									remaining_peers.remove(&peer);
+
+									if remaining_peers.is_empty() {
+										log::info!(target: LOG_TARGET, "{peer_id:?} All peers discovered");
+
+										num_finished.fetch_add(1, std::sync::atomic::Ordering::AcqRel);
+									}
+								},
+
+								event => {
+									log::info!(target: LOG_TARGET, "{peer_id:?} Discovery event: {event:?}");
+								}
+							}
+						}
+					}
+				}
+			};
+
+			futures.push(future);
+		}
+
+		// Futures will exit when all peers are discovered.
+		tokio::time::timeout(Duration::from_secs(60), futures.next())
+			.await
+			.expect("All peers should finish within 60 seconds");
+	}
+}

bizinikiwi/client/network/src/litep2p/peerstore.rs

@@ -0,0 +1,481 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! `Peerstore` implementation for `litep2p`.
+//!
+//! `Peerstore` is responsible for storing information about remote peers
+//! such as their addresses, reputations, supported protocols etc.
+
+use crate::{
+	peer_store::{PeerStoreProvider, ProtocolHandle},
+	service::{metrics::PeerStoreMetrics, traits::PeerStore},
+	ObservedRole, ReputationChange,
+};
+
+use parking_lot::Mutex;
+use prometheus_endpoint::Registry;
+use wasm_timer::Delay;
+
+use pezsc_network_types::PeerId;
+
+use std::{
+	collections::{HashMap, HashSet},
+	sync::Arc,
+	time::{Duration, Instant},
+};
+
+/// Logging target for the file.
+const LOG_TARGET: &str = "sub-libp2p::peerstore";
+
+/// We don't accept nodes whose reputation is under this value.
+pub const BANNED_THRESHOLD: i32 = 71 * (i32::MIN / 100);
+
+/// Relative decrement of a reputation value that is applied every second. I.e., for inverse
+/// decrement of 200 we decrease absolute value of the reputation by 1/200.
+///
+/// This corresponds to a factor of `k = 0.995`, where k = 1 - 1 / INVERSE_DECREMENT.
+///
+/// It takes ~ `ln(0.5) / ln(k)` seconds to reduce the reputation by half, or 138.63 seconds for the
+/// values above.
+///
+/// In this setup:
+/// - `i32::MAX` becomes 0 in exactly 3544 seconds, or approximately 59 minutes
+/// - `i32::MIN` escapes the banned threshold in 69 seconds
+const INVERSE_DECREMENT: i32 = 200;
+
+/// Amount of time between the moment we last updated the [`PeerStore`] entry and the moment we
+/// remove it, once the reputation value reaches 0.
+const FORGET_AFTER: Duration = Duration::from_secs(3600);
+
+/// Peer information.
+#[derive(Debug, Clone, Copy)]
+struct PeerInfo {
+	/// Reputation of the peer.
+	reputation: i32,
+
+	/// Instant when the peer was last updated.
+	last_updated: Instant,
+
+	/// Role of the peer, if known.
+	role: Option<ObservedRole>,
+}
+
+impl Default for PeerInfo {
+	fn default() -> Self {
+		Self { reputation: 0i32, last_updated: Instant::now(), role: None }
+	}
+}
+
+impl PeerInfo {
+	fn is_banned(&self) -> bool {
+		self.reputation < BANNED_THRESHOLD
+	}
+
+	fn add_reputation(&mut self, increment: i32) {
+		self.reputation = self.reputation.saturating_add(increment);
+		self.bump_last_updated();
+	}
+
+	fn decay_reputation(&mut self, seconds_passed: u64) {
+		// Note that decaying the reputation value happens "on its own",
+		// so we don't do `bump_last_updated()`.
+		for _ in 0..seconds_passed {
+			let mut diff = self.reputation / INVERSE_DECREMENT;
+			if diff == 0 && self.reputation < 0 {
+				diff = -1;
+			} else if diff == 0 && self.reputation > 0 {
+				diff = 1;
+			}
+
+			self.reputation = self.reputation.saturating_sub(diff);
+
+			if self.reputation == 0 {
+				break;
+			}
+		}
+	}
+
+	fn bump_last_updated(&mut self) {
+		self.last_updated = Instant::now();
+	}
+}
+
+#[derive(Debug, Default)]
+pub struct PeerstoreHandleInner {
+	peers: HashMap<PeerId, PeerInfo>,
+	protocols: Vec<Arc<dyn ProtocolHandle>>,
+	metrics: Option<PeerStoreMetrics>,
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct PeerstoreHandle(Arc<Mutex<PeerstoreHandleInner>>);
+
+impl PeerstoreHandle {
+	/// Constructs a new [`PeerstoreHandle`].
+	fn new(
+		peers: HashMap<PeerId, PeerInfo>,
+		protocols: Vec<Arc<dyn ProtocolHandle>>,
+		metrics: Option<PeerStoreMetrics>,
+	) -> Self {
+		Self(Arc::new(Mutex::new(PeerstoreHandleInner { peers, protocols, metrics })))
+	}
+
+	/// Add known peer to [`Peerstore`].
+	pub fn add_known_peer(&self, peer: PeerId) {
+		self.0
+			.lock()
+			.peers
+			.insert(peer, PeerInfo { reputation: 0i32, last_updated: Instant::now(), role: None });
+	}
+
+	pub fn peer_count(&self) -> usize {
+		self.0.lock().peers.len()
+	}
+
+	fn progress_time(&self, seconds_passed: u64) {
+		if seconds_passed == 0 {
+			return;
+		}
+
+		let mut lock = self.0.lock();
+
+		// Drive reputation values towards 0.
+		lock.peers
+			.iter_mut()
+			.for_each(|(_, info)| info.decay_reputation(seconds_passed));
+
+		// Retain only entries with non-zero reputation values or not expired ones.
+		let now = Instant::now();
+		let mut num_banned_peers = 0;
+		lock.peers.retain(|_, info| {
+			if info.is_banned() {
+				num_banned_peers += 1;
+			}
+			info.reputation != 0 || info.last_updated + FORGET_AFTER > now
+		});
+
+		if let Some(metrics) = &lock.metrics {
+			metrics.num_discovered.set(lock.peers.len() as u64);
+			metrics.num_banned_peers.set(num_banned_peers);
+		}
+	}
+}
+
+impl PeerStoreProvider for PeerstoreHandle {
+	fn is_banned(&self, peer: &PeerId) -> bool {
+		self.0.lock().peers.get(peer).map_or(false, |info| info.is_banned())
+	}
+
+	/// Register a protocol handle to disconnect peers whose reputation drops below the threshold.
+	fn register_protocol(&self, protocol_handle: Arc<dyn ProtocolHandle>) {
+		self.0.lock().protocols.push(protocol_handle);
+	}
+
+	/// Report peer disconnection for reputation adjustment.
+	fn report_disconnect(&self, _peer: PeerId) {
+		unimplemented!();
+	}
+
+	/// Adjust peer reputation.
+	fn report_peer(&self, peer_id: PeerId, change: ReputationChange) {
+		let mut lock = self.0.lock();
+		let peer_info = lock.peers.entry(peer_id).or_default();
+		let was_banned = peer_info.is_banned();
+		peer_info.add_reputation(change.value);
+		let peer_reputation = peer_info.reputation;
+
+		log::trace!(
+			target: LOG_TARGET,
+			"Report {}: {:+} to {}. Reason: {}.",
+			peer_id,
+			change.value,
+			peer_reputation,
+			change.reason,
+		);
+
+		if !peer_info.is_banned() {
+			if was_banned {
+				log::info!(
+					target: LOG_TARGET,
+					"Peer {} is now unbanned: {:+} to {}. Reason: {}.",
+					peer_id,
+					change.value,
+					peer_reputation,
+					change.reason,
+				);
+			}
+			return;
+		}
+
+		// Peer is currently banned, disconnect it from all protocols.
+		lock.protocols.iter().for_each(|handle| handle.disconnect_peer(peer_id.into()));
+
+		// The peer is banned for the first time.
+		if !was_banned {
+			log::warn!(
+				target: LOG_TARGET,
+				"Report {}: {:+} to {}. Reason: {}. Banned, disconnecting.",
+				peer_id,
+				change.value,
+				peer_reputation,
+				change.reason,
+			);
+			return;
+		}
+
+		// The peer was already banned and it got another negative report.
+		// This may happen during a batch report.
+		if change.value < 0 {
+			log::debug!(
+				target: LOG_TARGET,
+				"Report {}: {:+} to {}. Reason: {}. Misbehaved during the ban threshold.",
+				peer_id,
+				change.value,
+				peer_reputation,
+				change.reason,
+			);
+		}
+	}
+
+	/// Set peer role.
+	fn set_peer_role(&self, peer: &PeerId, role: ObservedRole) {
+		self.0.lock().peers.entry(*peer).or_default().role = Some(role);
+	}
+
+	/// Get peer reputation.
+	fn peer_reputation(&self, peer: &PeerId) -> i32 {
+		self.0.lock().peers.get(peer).map_or(0i32, |info| info.reputation)
+	}
+
+	/// Get peer role, if available.
+	fn peer_role(&self, peer: &PeerId) -> Option<ObservedRole> {
+		self.0.lock().peers.get(peer).and_then(|info| info.role)
+	}
+
+	/// Get candidates with highest reputations for initiating outgoing connections.
+	fn outgoing_candidates(&self, count: usize, ignored: HashSet<PeerId>) -> Vec<PeerId> {
+		let handle = self.0.lock();
+
+		let mut candidates = handle
+			.peers
+			.iter()
+			.filter_map(|(peer, info)| {
+				(!ignored.contains(&peer) && !info.is_banned()).then_some((*peer, info.reputation))
+			})
+			.collect::<Vec<(PeerId, _)>>();
+		candidates.sort_by(|(_, a), (_, b)| b.cmp(a));
+		candidates
+			.into_iter()
+			.take(count)
+			.map(|(peer, _score)| peer)
+			.collect::<Vec<_>>()
+	}
+
+	/// Add known peer.
+	fn add_known_peer(&self, peer: PeerId) {
+		self.0.lock().peers.entry(peer).or_default().last_updated = Instant::now();
+	}
+}
+
+/// `Peerstore` handle for testing.
+///
+/// This instance of `Peerstore` is not shared between protocols.
+#[cfg(test)]
+pub fn peerstore_handle_test() -> PeerstoreHandle {
+	PeerstoreHandle(Arc::new(Mutex::new(Default::default())))
+}
+
+/// Peerstore implementation.
+pub struct Peerstore {
+	/// Handle to `Peerstore`.
+	peerstore_handle: PeerstoreHandle,
+}
+
+impl Peerstore {
+	/// Create new [`Peerstore`].
+	pub fn new(bootnodes: Vec<PeerId>, metrics_registry: Option<Registry>) -> Self {
+		let metrics = if let Some(registry) = &metrics_registry {
+			PeerStoreMetrics::register(registry)
+				.map_err(|err| {
+					log::error!(target: LOG_TARGET, "Failed to register peer store metrics: {}", err);
+					err
+				})
+				.ok()
+		} else {
+			None
+		};
+
+		let peerstore_handle = PeerstoreHandle::new(
+			bootnodes.iter().map(|peer_id| (*peer_id, PeerInfo::default())).collect(),
+			Vec::new(),
+			metrics,
+		);
+
+		Self { peerstore_handle }
+	}
+
+	/// Get mutable reference to the underlying [`PeerstoreHandle`].
+	pub fn handle(&mut self) -> &mut PeerstoreHandle {
+		&mut self.peerstore_handle
+	}
+
+	/// Add known peer to [`Peerstore`].
+	pub fn add_known_peer(&mut self, peer: PeerId) {
+		self.peerstore_handle.add_known_peer(peer);
+	}
+
+	/// Start [`Peerstore`] event loop.
+	async fn run(self) {
+		let started = Instant::now();
+		let mut latest_time_update = started;
+
+		loop {
+			let now = Instant::now();
+			// We basically do `(now - self.latest_update).as_secs()`, except that by the way we do
+			// it we know that we're not going to miss seconds because of rounding to integers.
+			let seconds_passed = {
+				let elapsed_latest = latest_time_update - started;
+				let elapsed_now = now - started;
+				latest_time_update = now;
+				elapsed_now.as_secs() - elapsed_latest.as_secs()
+			};
+
+			self.peerstore_handle.progress_time(seconds_passed);
+			let _ = Delay::new(Duration::from_secs(1)).await;
+		}
+	}
+}
+
+#[async_trait::async_trait]
+impl PeerStore for Peerstore {
+	/// Get handle to `PeerStore`.
+	fn handle(&self) -> Arc<dyn PeerStoreProvider> {
+		Arc::new(self.peerstore_handle.clone())
+	}
+
+	/// Start running `PeerStore` event loop.
+	async fn run(self) {
+		self.run().await;
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::{PeerInfo, PeerStoreProvider, Peerstore};
+
+	#[test]
+	fn decaying_zero_reputation_yields_zero() {
+		let mut peer_info = PeerInfo::default();
+		assert_eq!(peer_info.reputation, 0);
+
+		peer_info.decay_reputation(1);
+		assert_eq!(peer_info.reputation, 0);
+
+		peer_info.decay_reputation(100_000);
+		assert_eq!(peer_info.reputation, 0);
+	}
+
+	#[test]
+	fn decaying_positive_reputation_decreases_it() {
+		const INITIAL_REPUTATION: i32 = 100;
+
+		let mut peer_info = PeerInfo::default();
+		peer_info.reputation = INITIAL_REPUTATION;
+
+		peer_info.decay_reputation(1);
+		assert!(peer_info.reputation >= 0);
+		assert!(peer_info.reputation < INITIAL_REPUTATION);
+	}
+
+	#[test]
+	fn decaying_negative_reputation_increases_it() {
+		const INITIAL_REPUTATION: i32 = -100;
+
+		let mut peer_info = PeerInfo::default();
+		peer_info.reputation = INITIAL_REPUTATION;
+
+		peer_info.decay_reputation(1);
+		assert!(peer_info.reputation <= 0);
+		assert!(peer_info.reputation > INITIAL_REPUTATION);
+	}
+
+	#[test]
+	fn decaying_max_reputation_finally_yields_zero() {
+		const INITIAL_REPUTATION: i32 = i32::MAX;
+		const SECONDS: u64 = 3544;
+
+		let mut peer_info = PeerInfo::default();
+		peer_info.reputation = INITIAL_REPUTATION;
+
+		peer_info.decay_reputation(SECONDS / 2);
+		assert!(peer_info.reputation > 0);
+
+		peer_info.decay_reputation(SECONDS / 2);
+		assert_eq!(peer_info.reputation, 0);
+	}
+
+	#[test]
+	fn decaying_min_reputation_finally_yields_zero() {
+		const INITIAL_REPUTATION: i32 = i32::MIN;
+		const SECONDS: u64 = 3544;
+
+		let mut peer_info = PeerInfo::default();
+		peer_info.reputation = INITIAL_REPUTATION;
+
+		peer_info.decay_reputation(SECONDS / 2);
+		assert!(peer_info.reputation < 0);
+
+		peer_info.decay_reputation(SECONDS / 2);
+		assert_eq!(peer_info.reputation, 0);
+	}
+
+	#[test]
+	fn report_banned_peers() {
+		let peer_a = pezsc_network_types::PeerId::random();
+		let peer_b = pezsc_network_types::PeerId::random();
+		let peer_c = pezsc_network_types::PeerId::random();
+
+		let metrics_registry = prometheus_endpoint::Registry::new();
+		let mut peerstore = Peerstore::new(
+			vec![peer_a, peer_b, peer_c].into_iter().map(Into::into).collect(),
+			Some(metrics_registry),
+		);
+		let metrics = peerstore.peerstore_handle.0.lock().metrics.as_ref().unwrap().clone();
+		let handle = peerstore.handle();
+
+		// Check initial state. Advance time to propagate peers.
+		handle.progress_time(1);
+		assert_eq!(metrics.num_discovered.get(), 3);
+		assert_eq!(metrics.num_banned_peers.get(), 0);
+
+		// Report 2 peers with a negative reputation.
+		handle.report_peer(
+			peer_a,
+			pezsc_network_common::types::ReputationChange { value: i32::MIN, reason: "test".into() },
+		);
+		handle.report_peer(
+			peer_b,
+			pezsc_network_common::types::ReputationChange { value: i32::MIN, reason: "test".into() },
+		);
+
+		// Advance time to propagate peers.
+		handle.progress_time(1);
+		assert_eq!(metrics.num_discovered.get(), 3);
+		assert_eq!(metrics.num_banned_peers.get(), 2);
+	}
+}

bizinikiwi/client/network/src/litep2p/service.rs

@@ -0,0 +1,584 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! `NetworkService` implementation for `litep2p`.
+
+use crate::{
+	config::MultiaddrWithPeerId,
+	litep2p::shim::{
+		notification::{config::ProtocolControlHandle, peerset::PeersetCommand},
+		request_response::OutboundRequest,
+	},
+	network_state::NetworkState,
+	peer_store::PeerStoreProvider,
+	service::out_events,
+	Event, IfDisconnected, NetworkDHTProvider, NetworkEventStream, NetworkPeers, NetworkRequest,
+	NetworkSigner, NetworkStateInfo, NetworkStatus, NetworkStatusProvider, OutboundFailure,
+	ProtocolName, RequestFailure, Signature,
+};
+
+use codec::DecodeAll;
+use futures::{channel::oneshot, stream::BoxStream};
+use libp2p::identity::SigningError;
+use litep2p::{
+	addresses::PublicAddresses, crypto::ed25519::Keypair,
+	types::multiaddr::Multiaddr as LiteP2pMultiaddr,
+};
+use parking_lot::RwLock;
+use pezsc_network_types::kad::{Key as KademliaKey, Record};
+
+use pezsc_network_common::{
+	role::{ObservedRole, Roles},
+	types::ReputationChange,
+};
+use pezsc_network_types::{
+	multiaddr::{Multiaddr, Protocol},
+	PeerId,
+};
+use pezsc_utils::mpsc::TracingUnboundedSender;
+
+use std::{
+	collections::{HashMap, HashSet},
+	sync::{atomic::Ordering, Arc},
+	time::Instant,
+};
+
+/// Logging target for the file.
+const LOG_TARGET: &str = "sub-libp2p";
+
+/// Commands sent by [`Litep2pNetworkService`] to
+/// [`Litep2pNetworkBackend`](super::Litep2pNetworkBackend).
+#[derive(Debug)]
+pub enum NetworkServiceCommand {
+	/// Find peers closest to `target` in the DHT.
+	FindClosestPeers {
+		/// Target peer ID.
+		target: PeerId,
+	},
+
+	/// Get value from DHT.
+	GetValue {
+		/// Record key.
+		key: KademliaKey,
+	},
+
+	/// Put value to DHT.
+	PutValue {
+		/// Record key.
+		key: KademliaKey,
+
+		/// Record value.
+		value: Vec<u8>,
+	},
+
+	/// Put value to DHT.
+	PutValueTo {
+		/// Record.
+		record: Record,
+		/// Peers we want to put the record.
+		peers: Vec<pezsc_network_types::PeerId>,
+		/// If we should update the local storage or not.
+		update_local_storage: bool,
+	},
+	/// Store record in the local DHT store.
+	StoreRecord {
+		/// Record key.
+		key: KademliaKey,
+
+		/// Record value.
+		value: Vec<u8>,
+
+		/// Original publisher of the record.
+		publisher: Option<PeerId>,
+
+		/// Record expiration time as measured by a local, monothonic clock.
+		expires: Option<Instant>,
+	},
+
+	/// Start providing `key`.
+	StartProviding { key: KademliaKey },
+
+	/// Stop providing `key`.
+	StopProviding { key: KademliaKey },
+
+	/// Get providers for `key`.
+	GetProviders { key: KademliaKey },
+
+	/// Query network status.
+	Status {
+		/// `oneshot::Sender` for sending the status.
+		tx: oneshot::Sender<NetworkStatus>,
+	},
+
+	/// Add `peers` to `protocol`'s reserved set.
+	AddPeersToReservedSet {
+		/// Protocol.
+		protocol: ProtocolName,
+
+		/// Reserved peers.
+		peers: HashSet<Multiaddr>,
+	},
+
+	/// Add known address for peer.
+	AddKnownAddress {
+		/// Peer ID.
+		peer: PeerId,
+
+		/// Address.
+		address: Multiaddr,
+	},
+
+	/// Set reserved peers for `protocol`.
+	SetReservedPeers {
+		/// Protocol.
+		protocol: ProtocolName,
+
+		/// Reserved peers.
+		peers: HashSet<Multiaddr>,
+	},
+
+	/// Disconnect peer from protocol.
+	DisconnectPeer {
+		/// Protocol.
+		protocol: ProtocolName,
+
+		/// Peer ID.
+		peer: PeerId,
+	},
+
+	/// Set protocol to reserved only (true/false) mode.
+	SetReservedOnly {
+		/// Protocol.
+		protocol: ProtocolName,
+
+		/// Reserved only?
+		reserved_only: bool,
+	},
+
+	/// Remove reserved peers from protocol.
+	RemoveReservedPeers {
+		/// Protocol.
+		protocol: ProtocolName,
+
+		/// Peers to remove from the reserved set.
+		peers: HashSet<PeerId>,
+	},
+
+	/// Create event stream for DHT events.
+	EventStream {
+		/// Sender for the events.
+		tx: out_events::Sender,
+	},
+}
+
+/// `NetworkService` implementation for `litep2p`.
+#[derive(Debug, Clone)]
+pub struct Litep2pNetworkService {
+	/// Local peer ID.
+	local_peer_id: litep2p::PeerId,
+
+	/// The `KeyPair` that defines the `PeerId` of the local node.
+	keypair: Keypair,
+
+	/// TX channel for sending commands to [`Litep2pNetworkBackend`](super::Litep2pNetworkBackend).
+	cmd_tx: TracingUnboundedSender<NetworkServiceCommand>,
+
+	/// Handle to `PeerStore`.
+	peer_store_handle: Arc<dyn PeerStoreProvider>,
+
+	/// Peerset handles.
+	peerset_handles: HashMap<ProtocolName, ProtocolControlHandle>,
+
+	/// Name for the block announce protocol.
+	block_announce_protocol: ProtocolName,
+
+	/// Installed request-response protocols.
+	request_response_protocols: HashMap<ProtocolName, TracingUnboundedSender<OutboundRequest>>,
+
+	/// Listen addresses.
+	listen_addresses: Arc<RwLock<HashSet<LiteP2pMultiaddr>>>,
+
+	/// External addresses.
+	external_addresses: PublicAddresses,
+}
+
+impl Litep2pNetworkService {
+	/// Create new [`Litep2pNetworkService`].
+	pub fn new(
+		local_peer_id: litep2p::PeerId,
+		keypair: Keypair,
+		cmd_tx: TracingUnboundedSender<NetworkServiceCommand>,
+		peer_store_handle: Arc<dyn PeerStoreProvider>,
+		peerset_handles: HashMap<ProtocolName, ProtocolControlHandle>,
+		block_announce_protocol: ProtocolName,
+		request_response_protocols: HashMap<ProtocolName, TracingUnboundedSender<OutboundRequest>>,
+		listen_addresses: Arc<RwLock<HashSet<LiteP2pMultiaddr>>>,
+		external_addresses: PublicAddresses,
+	) -> Self {
+		Self {
+			local_peer_id,
+			keypair,
+			cmd_tx,
+			peer_store_handle,
+			peerset_handles,
+			block_announce_protocol,
+			request_response_protocols,
+			listen_addresses,
+			external_addresses,
+		}
+	}
+}
+
+impl NetworkSigner for Litep2pNetworkService {
+	fn sign_with_local_identity(&self, msg: Vec<u8>) -> Result<Signature, SigningError> {
+		let public_key = self.keypair.public();
+		let bytes = self.keypair.sign(msg.as_ref());
+
+		Ok(Signature {
+			public_key: crate::service::signature::PublicKey::Litep2p(
+				litep2p::crypto::PublicKey::Ed25519(public_key),
+			),
+			bytes,
+		})
+	}
+
+	fn verify(
+		&self,
+		peer: PeerId,
+		public_key: &Vec<u8>,
+		signature: &Vec<u8>,
+		message: &Vec<u8>,
+	) -> Result<bool, String> {
+		let identity = litep2p::PeerId::from_public_key_protobuf(&public_key);
+		let public_key = litep2p::crypto::RemotePublicKey::from_protobuf_encoding(&public_key)
+			.map_err(|error| error.to_string())?;
+		let peer: litep2p::PeerId = peer.into();
+
+		Ok(peer == identity && public_key.verify(message, signature))
+	}
+}
+
+impl NetworkDHTProvider for Litep2pNetworkService {
+	fn find_closest_peers(&self, target: PeerId) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::FindClosestPeers { target });
+	}
+
+	fn get_value(&self, key: &KademliaKey) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::GetValue { key: key.clone() });
+	}
+
+	fn put_value(&self, key: KademliaKey, value: Vec<u8>) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::PutValue { key, value });
+	}
+
+	fn put_record_to(&self, record: Record, peers: HashSet<PeerId>, update_local_storage: bool) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::PutValueTo {
+			record: Record {
+				key: record.key.to_vec().into(),
+				value: record.value,
+				publisher: record.publisher.map(|peer_id| {
+					let peer_id: pezsc_network_types::PeerId = peer_id.into();
+					peer_id.into()
+				}),
+				expires: record.expires,
+			},
+			peers: peers.into_iter().collect(),
+			update_local_storage,
+		});
+	}
+
+	fn store_record(
+		&self,
+		key: KademliaKey,
+		value: Vec<u8>,
+		publisher: Option<PeerId>,
+		expires: Option<Instant>,
+	) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::StoreRecord {
+			key,
+			value,
+			publisher,
+			expires,
+		});
+	}
+
+	fn start_providing(&self, key: KademliaKey) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::StartProviding { key });
+	}
+
+	fn stop_providing(&self, key: KademliaKey) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::StopProviding { key });
+	}
+
+	fn get_providers(&self, key: KademliaKey) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::GetProviders { key });
+	}
+}
+
+#[async_trait::async_trait]
+impl NetworkStatusProvider for Litep2pNetworkService {
+	async fn status(&self) -> Result<NetworkStatus, ()> {
+		let (tx, rx) = oneshot::channel();
+		self.cmd_tx
+			.unbounded_send(NetworkServiceCommand::Status { tx })
+			.map_err(|_| ())?;
+
+		rx.await.map_err(|_| ())
+	}
+
+	async fn network_state(&self) -> Result<NetworkState, ()> {
+		Ok(NetworkState {
+			peer_id: self.local_peer_id.to_base58(),
+			listened_addresses: self
+				.listen_addresses
+				.read()
+				.iter()
+				.cloned()
+				.map(|a| Multiaddr::from(a).into())
+				.collect(),
+			external_addresses: self
+				.external_addresses
+				.get_addresses()
+				.into_iter()
+				.map(|a| Multiaddr::from(a).into())
+				.collect(),
+			connected_peers: HashMap::new(),
+			not_connected_peers: HashMap::new(),
+			// TODO: Check what info we can include here.
+			//       Issue reference: https://github.com/pezkuwichain/kurdistan-sdk/issues/15.
+			peerset: serde_json::json!(
+				"Unimplemented. See https://github.com/pezkuwichain/kurdistan-sdk/issues/15."
+			),
+		})
+	}
+}
+
+// Manual implementation to avoid extra boxing here
+// TODO: functions modifying peerset state could be modified to call peerset directly if the
+// `Multiaddr` only contains a `PeerId`
+#[async_trait::async_trait]
+impl NetworkPeers for Litep2pNetworkService {
+	fn set_authorized_peers(&self, peers: HashSet<PeerId>) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::SetReservedPeers {
+			protocol: self.block_announce_protocol.clone(),
+			peers: peers
+				.into_iter()
+				.map(|peer| Multiaddr::empty().with(Protocol::P2p(peer.into())))
+				.collect(),
+		});
+	}
+
+	fn set_authorized_only(&self, reserved_only: bool) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::SetReservedOnly {
+			protocol: self.block_announce_protocol.clone(),
+			reserved_only,
+		});
+	}
+
+	fn add_known_address(&self, peer: PeerId, address: Multiaddr) {
+		let _ = self
+			.cmd_tx
+			.unbounded_send(NetworkServiceCommand::AddKnownAddress { peer, address });
+	}
+
+	fn peer_reputation(&self, peer_id: &PeerId) -> i32 {
+		self.peer_store_handle.peer_reputation(peer_id)
+	}
+
+	fn report_peer(&self, peer: PeerId, cost_benefit: ReputationChange) {
+		self.peer_store_handle.report_peer(peer, cost_benefit);
+	}
+
+	fn disconnect_peer(&self, peer: PeerId, protocol: ProtocolName) {
+		let _ = self
+			.cmd_tx
+			.unbounded_send(NetworkServiceCommand::DisconnectPeer { protocol, peer });
+	}
+
+	fn accept_unreserved_peers(&self) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::SetReservedOnly {
+			protocol: self.block_announce_protocol.clone(),
+			reserved_only: false,
+		});
+	}
+
+	fn deny_unreserved_peers(&self) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::SetReservedOnly {
+			protocol: self.block_announce_protocol.clone(),
+			reserved_only: true,
+		});
+	}
+
+	fn add_reserved_peer(&self, peer: MultiaddrWithPeerId) -> Result<(), String> {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::AddPeersToReservedSet {
+			protocol: self.block_announce_protocol.clone(),
+			peers: HashSet::from_iter([peer.concat().into()]),
+		});
+
+		Ok(())
+	}
+
+	fn remove_reserved_peer(&self, peer: PeerId) {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::RemoveReservedPeers {
+			protocol: self.block_announce_protocol.clone(),
+			peers: HashSet::from_iter([peer]),
+		});
+	}
+
+	fn set_reserved_peers(
+		&self,
+		protocol: ProtocolName,
+		peers: HashSet<Multiaddr>,
+	) -> Result<(), String> {
+		let _ = self
+			.cmd_tx
+			.unbounded_send(NetworkServiceCommand::SetReservedPeers { protocol, peers });
+		Ok(())
+	}
+
+	fn add_peers_to_reserved_set(
+		&self,
+		protocol: ProtocolName,
+		peers: HashSet<Multiaddr>,
+	) -> Result<(), String> {
+		let _ = self
+			.cmd_tx
+			.unbounded_send(NetworkServiceCommand::AddPeersToReservedSet { protocol, peers });
+		Ok(())
+	}
+
+	fn remove_peers_from_reserved_set(
+		&self,
+		protocol: ProtocolName,
+		peers: Vec<PeerId>,
+	) -> Result<(), String> {
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::RemoveReservedPeers {
+			protocol,
+			peers: peers.into_iter().map(From::from).collect(),
+		});
+
+		Ok(())
+	}
+
+	fn sync_num_connected(&self) -> usize {
+		self.peerset_handles
+			.get(&self.block_announce_protocol)
+			.map_or(0usize, |handle| handle.connected_peers.load(Ordering::Relaxed))
+	}
+
+	fn peer_role(&self, peer: PeerId, handshake: Vec<u8>) -> Option<ObservedRole> {
+		match Roles::decode_all(&mut &handshake[..]) {
+			Ok(role) => Some(role.into()),
+			Err(_) => {
+				log::debug!(target: LOG_TARGET, "handshake doesn't contain peer role: {handshake:?}");
+				self.peer_store_handle.peer_role(&(peer.into()))
+			},
+		}
+	}
+
+	/// Get the list of reserved peers.
+	///
+	/// Returns an error if the `NetworkWorker` is no longer running.
+	async fn reserved_peers(&self) -> Result<Vec<PeerId>, ()> {
+		let Some(handle) = self.peerset_handles.get(&self.block_announce_protocol) else {
+			return Err(());
+		};
+		let (tx, rx) = oneshot::channel();
+
+		handle
+			.tx
+			.unbounded_send(PeersetCommand::GetReservedPeers { tx })
+			.map_err(|_| ())?;
+
+		// the channel can only be closed if `Peerset` no longer exists
+		rx.await.map_err(|_| ())
+	}
+}
+
+impl NetworkEventStream for Litep2pNetworkService {
+	fn event_stream(&self, stream_name: &'static str) -> BoxStream<'static, Event> {
+		let (tx, rx) = out_events::channel(stream_name, 100_000);
+		let _ = self.cmd_tx.unbounded_send(NetworkServiceCommand::EventStream { tx });
+		Box::pin(rx)
+	}
+}
+
+impl NetworkStateInfo for Litep2pNetworkService {
+	fn external_addresses(&self) -> Vec<Multiaddr> {
+		self.external_addresses.get_addresses().into_iter().map(Into::into).collect()
+	}
+
+	fn listen_addresses(&self) -> Vec<Multiaddr> {
+		self.listen_addresses.read().iter().cloned().map(Into::into).collect()
+	}
+
+	fn local_peer_id(&self) -> PeerId {
+		self.local_peer_id.into()
+	}
+}
+
+// Manual implementation to avoid extra boxing here
+#[async_trait::async_trait]
+impl NetworkRequest for Litep2pNetworkService {
+	async fn request(
+		&self,
+		target: PeerId,
+		protocol: ProtocolName,
+		request: Vec<u8>,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+		connect: IfDisconnected,
+	) -> Result<(Vec<u8>, ProtocolName), RequestFailure> {
+		let (tx, rx) = oneshot::channel();
+
+		self.start_request(target, protocol, request, fallback_request, tx, connect);
+
+		match rx.await {
+			Ok(v) => v,
+			// The channel can only be closed if the network worker no longer exists. If the
+			// network worker no longer exists, then all connections to `target` are necessarily
+			// closed, and we legitimately report this situation as a "ConnectionClosed".
+			Err(_) => Err(RequestFailure::Network(OutboundFailure::ConnectionClosed)),
+		}
+	}
+
+	fn start_request(
+		&self,
+		peer: PeerId,
+		protocol: ProtocolName,
+		request: Vec<u8>,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+		sender: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+		connect: IfDisconnected,
+	) {
+		match self.request_response_protocols.get(&protocol) {
+			Some(tx) => {
+				let _ = tx.unbounded_send(OutboundRequest::new(
+					peer,
+					request,
+					sender,
+					fallback_request,
+					connect,
+				));
+			},
+			None => log::warn!(
+				target: LOG_TARGET,
+				"{protocol} doesn't exist, cannot send request to {peer:?}"
+			),
+		}
+	}
+}

bizinikiwi/client/network/src/litep2p/shim/bitswap.rs

@@ -0,0 +1,104 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Shim for litep2p's Bitswap implementation to make it work with `sc-network`.
+
+use futures::StreamExt;
+use litep2p::protocol::libp2p::bitswap::{
+	BitswapEvent, BitswapHandle, BlockPresenceType, Config, ResponseType, WantType,
+};
+
+use pezsc_client_api::BlockBackend;
+use pezsp_runtime::traits::Block as BlockT;
+
+use std::{future::Future, pin::Pin, sync::Arc};
+
+/// Logging target for the file.
+const LOG_TARGET: &str = "sub-libp2p::bitswap";
+
+pub struct BitswapServer<Block: BlockT> {
+	/// Bitswap handle.
+	handle: BitswapHandle,
+
+	/// Blockchain client.
+	client: Arc<dyn BlockBackend<Block> + Send + Sync>,
+}
+
+impl<Block: BlockT> BitswapServer<Block> {
+	/// Create new [`BitswapServer`].
+	pub fn new(
+		client: Arc<dyn BlockBackend<Block> + Send + Sync>,
+	) -> (Pin<Box<dyn Future<Output = ()> + Send>>, Config) {
+		let (config, handle) = Config::new();
+		let bitswap = Self { client, handle };
+
+		(Box::pin(async move { bitswap.run().await }), config)
+	}
+
+	async fn run(mut self) {
+		log::debug!(target: LOG_TARGET, "starting bitswap server");
+
+		while let Some(event) = self.handle.next().await {
+			match event {
+				BitswapEvent::Request { peer, cids } => {
+					log::debug!(target: LOG_TARGET, "handle bitswap request from {peer:?} for {cids:?}");
+
+					let response: Vec<ResponseType> = cids
+						.into_iter()
+						.map(|(cid, want_type)| {
+							let mut hash = Block::Hash::default();
+							hash.as_mut().copy_from_slice(&cid.hash().digest()[0..32]);
+							let transaction = match self.client.indexed_transaction(hash) {
+								Ok(ex) => ex,
+								Err(error) => {
+									log::error!(target: LOG_TARGET, "error retrieving transaction {hash}: {error}");
+									None
+								},
+							};
+
+							match transaction {
+								Some(transaction) => {
+									log::trace!(target: LOG_TARGET, "found cid {cid:?}, hash {hash:?}");
+
+									match want_type {
+										WantType::Block =>
+											ResponseType::Block { cid, block: transaction },
+										_ => ResponseType::Presence {
+											cid,
+											presence: BlockPresenceType::Have,
+										},
+									}
+								},
+								None => {
+									log::trace!(target: LOG_TARGET, "missing cid {cid:?}, hash {hash:?}");
+
+									ResponseType::Presence {
+										cid,
+										presence: BlockPresenceType::DontHave,
+									}
+								},
+							}
+						})
+						.collect();
+
+					self.handle.send_response(peer, response).await;
+				},
+			}
+		}
+	}
+}

bizinikiwi/client/network/src/litep2p/shim/mod.rs

@@ -0,0 +1,23 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Shims for fitting `litep2p` APIs to `sc-network` APIs.
+
+pub(crate) mod bitswap;
+pub(crate) mod notification;
+pub(crate) mod request_response;

bizinikiwi/client/network/src/litep2p/shim/notification/config.rs

@@ -0,0 +1,168 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! `litep2p` notification protocol configuration.
+
+use crate::{
+	config::{MultiaddrWithPeerId, NonReservedPeerMode, NotificationHandshake, SetConfig},
+	litep2p::shim::notification::{
+		peerset::{Peerset, PeersetCommand},
+		NotificationProtocol,
+	},
+	peer_store::PeerStoreProvider,
+	service::{metrics::NotificationMetrics, traits::NotificationConfig},
+	NotificationService, ProtocolName,
+};
+
+use litep2p::protocol::notification::{Config, ConfigBuilder};
+
+use pezsc_utils::mpsc::TracingUnboundedSender;
+
+use std::sync::{atomic::AtomicUsize, Arc};
+
+/// Handle for controlling the notification protocol.
+#[derive(Debug, Clone)]
+pub struct ProtocolControlHandle {
+	/// TX channel for sending commands to `Peerset` of the notification protocol.
+	pub tx: TracingUnboundedSender<PeersetCommand>,
+
+	/// Peers currently connected to this protocol.
+	pub connected_peers: Arc<AtomicUsize>,
+}
+
+impl ProtocolControlHandle {
+	/// Create new [`ProtocolControlHandle`].
+	pub fn new(
+		tx: TracingUnboundedSender<PeersetCommand>,
+		connected_peers: Arc<AtomicUsize>,
+	) -> Self {
+		Self { tx, connected_peers }
+	}
+}
+
+/// Configuration for the notification protocol.
+#[derive(Debug)]
+pub struct NotificationProtocolConfig {
+	/// Name of the notifications protocols of this set. A substream on this set will be
+	/// considered established once this protocol is open.
+	pub protocol_name: ProtocolName,
+
+	/// Maximum allowed size of single notifications.
+	max_notification_size: usize,
+
+	/// Base configuration.
+	set_config: SetConfig,
+
+	/// `litep2p` notification config.
+	pub config: Config,
+
+	/// Handle for controlling the notification protocol.
+	pub handle: ProtocolControlHandle,
+}
+
+impl NotificationProtocolConfig {
+	// Create new [`NotificationProtocolConfig`].
+	pub fn new(
+		protocol_name: ProtocolName,
+		fallback_names: Vec<ProtocolName>,
+		max_notification_size: usize,
+		handshake: Option<NotificationHandshake>,
+		set_config: SetConfig,
+		metrics: NotificationMetrics,
+		peerstore_handle: Arc<dyn PeerStoreProvider>,
+	) -> (Self, Box<dyn NotificationService>) {
+		// create `Peerset`/`Peerstore` handle for the protocol
+		let connected_peers = Arc::new(Default::default());
+		let (peerset, peerset_tx) = Peerset::new(
+			protocol_name.clone(),
+			set_config.out_peers as usize,
+			set_config.in_peers as usize,
+			set_config.non_reserved_mode == NonReservedPeerMode::Deny,
+			set_config.reserved_nodes.iter().map(|address| address.peer_id).collect(),
+			Arc::clone(&connected_peers),
+			peerstore_handle,
+		);
+
+		// create `litep2p` notification protocol configuration for the protocol
+		//
+		// NOTE: currently only dummy value is given as the handshake as protocols (apart from
+		// syncing) are not configuring their own handshake and instead default to role being the
+		// handshake. As the time of writing this, most protocols are not aware of the role and
+		// that should be refactored in the future.
+		let (config, handle) = ConfigBuilder::new(protocol_name.clone().into())
+			.with_handshake(handshake.map_or(vec![1], |handshake| (*handshake).to_vec()))
+			.with_max_size(max_notification_size as usize)
+			.with_auto_accept_inbound(true)
+			.with_fallback_names(fallback_names.into_iter().map(From::from).collect())
+			.build();
+
+		// initialize the actual object implementing `NotificationService` and combine the
+		// `litep2p::NotificationHandle` with `Peerset` to implement a full and independent
+		// notification protocol runner
+		let protocol = NotificationProtocol::new(protocol_name.clone(), handle, peerset, metrics);
+
+		(
+			Self {
+				protocol_name,
+				max_notification_size,
+				set_config,
+				config,
+				handle: ProtocolControlHandle::new(peerset_tx, connected_peers),
+			},
+			Box::new(protocol),
+		)
+	}
+
+	/// Get reference to protocol name.
+	pub fn protocol_name(&self) -> &ProtocolName {
+		&self.protocol_name
+	}
+
+	/// Get reference to `SetConfig`.
+	pub fn set_config(&self) -> &SetConfig {
+		&self.set_config
+	}
+
+	/// Modifies the configuration to allow non-reserved nodes.
+	pub fn allow_non_reserved(&mut self, in_peers: u32, out_peers: u32) {
+		self.set_config.in_peers = in_peers;
+		self.set_config.out_peers = out_peers;
+		self.set_config.non_reserved_mode = NonReservedPeerMode::Accept;
+	}
+
+	/// Add a node to the list of reserved nodes.
+	pub fn add_reserved(&mut self, peer: MultiaddrWithPeerId) {
+		self.set_config.reserved_nodes.push(peer);
+	}
+
+	/// Get maximum notification size.
+	pub fn max_notification_size(&self) -> usize {
+		self.max_notification_size
+	}
+}
+
+impl NotificationConfig for NotificationProtocolConfig {
+	fn set_config(&self) -> &SetConfig {
+		&self.set_config
+	}
+
+	/// Get reference to protocol name.
+	fn protocol_name(&self) -> &ProtocolName {
+		&self.protocol_name
+	}
+}

bizinikiwi/client/network/src/litep2p/shim/notification/mod.rs

@@ -0,0 +1,376 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Shim for `litep2p::NotificationHandle` to combine `Peerset`-like behavior
+//! with `NotificationService`.
+
+use crate::{
+	error::Error,
+	litep2p::shim::notification::peerset::{OpenResult, Peerset, PeersetNotificationCommand},
+	service::{
+		metrics::NotificationMetrics,
+		traits::{NotificationEvent as BizinikiwiNotificationEvent, ValidationResult},
+	},
+	MessageSink, NotificationService, ProtocolName,
+};
+
+use futures::{future::BoxFuture, stream::FuturesUnordered, StreamExt};
+use litep2p::protocol::notification::{
+	NotificationEvent, NotificationHandle, NotificationSink,
+	ValidationResult as Litep2pValidationResult,
+};
+use tokio::sync::oneshot;
+
+use pezsc_network_types::PeerId;
+
+use std::{collections::HashSet, fmt};
+
+pub mod config;
+pub mod peerset;
+
+#[cfg(test)]
+mod tests;
+
+/// Logging target for the file.
+const LOG_TARGET: &str = "sub-libp2p::notification";
+
+/// Wrapper over `litep2p`'s notification sink.
+pub struct Litep2pMessageSink {
+	/// Protocol.
+	protocol: ProtocolName,
+
+	/// Remote peer ID.
+	peer: PeerId,
+
+	/// Notification sink.
+	sink: NotificationSink,
+
+	/// Notification metrics.
+	metrics: NotificationMetrics,
+}
+
+impl Litep2pMessageSink {
+	/// Create new [`Litep2pMessageSink`].
+	fn new(
+		peer: PeerId,
+		protocol: ProtocolName,
+		sink: NotificationSink,
+		metrics: NotificationMetrics,
+	) -> Self {
+		Self { protocol, peer, sink, metrics }
+	}
+}
+
+#[async_trait::async_trait]
+impl MessageSink for Litep2pMessageSink {
+	/// Send synchronous `notification` to the peer associated with this [`MessageSink`].
+	fn send_sync_notification(&self, notification: Vec<u8>) {
+		let size = notification.len();
+
+		match self.sink.send_sync_notification(notification) {
+			Ok(_) => self.metrics.register_notification_sent(&self.protocol, size),
+			Err(error) => log::trace!(
+				target: LOG_TARGET,
+				"{}: failed to send sync notification to {:?}: {error:?}",
+				self.protocol,
+				self.peer,
+			),
+		}
+	}
+
+	/// Send an asynchronous `notification` to to the peer associated with this [`MessageSink`],
+	/// allowing sender to exercise backpressure.
+	///
+	/// Returns an error if the peer does not exist.
+	async fn send_async_notification(&self, notification: Vec<u8>) -> Result<(), Error> {
+		let size = notification.len();
+
+		match self.sink.send_async_notification(notification).await {
+			Ok(_) => {
+				self.metrics.register_notification_sent(&self.protocol, size);
+				Ok(())
+			},
+			Err(error) => {
+				log::trace!(
+					target: LOG_TARGET,
+					"{}: failed to send async notification to {:?}: {error:?}",
+					self.protocol,
+					self.peer,
+				);
+
+				Err(Error::Litep2p(error))
+			},
+		}
+	}
+}
+
+/// Notification protocol implementation.
+pub struct NotificationProtocol {
+	/// Protocol name.
+	protocol: ProtocolName,
+
+	/// `litep2p` notification handle.
+	handle: NotificationHandle,
+
+	/// Peerset for the notification protocol.
+	///
+	/// Listens to peering-related events and either opens or closes substreams to remote peers.
+	peerset: Peerset,
+
+	/// Pending validations for inbound substreams.
+	pending_validations: FuturesUnordered<
+		BoxFuture<'static, (PeerId, Result<ValidationResult, oneshot::error::RecvError>)>,
+	>,
+
+	/// Pending cancels.
+	pending_cancels: HashSet<litep2p::PeerId>,
+
+	/// Notification metrics.
+	metrics: NotificationMetrics,
+}
+
+impl fmt::Debug for NotificationProtocol {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		f.debug_struct("NotificationProtocol")
+			.field("protocol", &self.protocol)
+			.field("handle", &self.handle)
+			.finish()
+	}
+}
+
+impl NotificationProtocol {
+	/// Create new [`NotificationProtocol`].
+	pub fn new(
+		protocol: ProtocolName,
+		handle: NotificationHandle,
+		peerset: Peerset,
+		metrics: NotificationMetrics,
+	) -> Self {
+		Self {
+			protocol,
+			handle,
+			peerset,
+			metrics,
+			pending_cancels: HashSet::new(),
+			pending_validations: FuturesUnordered::new(),
+		}
+	}
+
+	/// Handle `Peerset` command.
+	async fn on_peerset_command(&mut self, command: PeersetNotificationCommand) {
+		if !command.open_peers.is_empty() {
+			log::trace!(target: LOG_TARGET, "{}: open substreams to {:?}", self.protocol, command.open_peers);
+			let _ = self
+				.handle
+				.open_substream_batch(command.open_peers.into_iter().map(From::from))
+				.await;
+		}
+
+		if !command.close_peers.is_empty() {
+			log::trace!(target: LOG_TARGET, "{}: close substreams to {:?}", self.protocol, command.close_peers);
+			self.handle
+				.close_substream_batch(command.close_peers.into_iter().map(From::from))
+				.await;
+		}
+	}
+}
+
+#[async_trait::async_trait]
+impl NotificationService for NotificationProtocol {
+	async fn open_substream(&mut self, _peer: PeerId) -> Result<(), ()> {
+		unimplemented!();
+	}
+
+	async fn close_substream(&mut self, _peer: PeerId) -> Result<(), ()> {
+		unimplemented!();
+	}
+
+	fn send_sync_notification(&mut self, peer: &PeerId, notification: Vec<u8>) {
+		let size = notification.len();
+
+		if let Ok(_) = self.handle.send_sync_notification(peer.into(), notification) {
+			self.metrics.register_notification_sent(&self.protocol, size);
+		}
+	}
+
+	async fn send_async_notification(
+		&mut self,
+		peer: &PeerId,
+		notification: Vec<u8>,
+	) -> Result<(), Error> {
+		let size = notification.len();
+
+		match self.handle.send_async_notification(peer.into(), notification).await {
+			Ok(_) => {
+				self.metrics.register_notification_sent(&self.protocol, size);
+				Ok(())
+			},
+			Err(_) => Err(Error::ChannelClosed),
+		}
+	}
+
+	/// Set handshake for the notification protocol replacing the old handshake.
+	async fn set_handshake(&mut self, handshake: Vec<u8>) -> Result<(), ()> {
+		self.handle.set_handshake(handshake);
+
+		Ok(())
+	}
+
+	/// Set handshake for the notification protocol replacing the old handshake.
+	///
+	/// For `litep2p` this is identical to `NotificationService::set_handshake()` since `litep2p`
+	/// allows updating the handshake synchronously.
+	fn try_set_handshake(&mut self, handshake: Vec<u8>) -> Result<(), ()> {
+		self.handle.set_handshake(handshake);
+
+		Ok(())
+	}
+
+	/// Make a copy of the object so it can be shared between protocol components
+	/// who wish to have access to the same underlying notification protocol.
+	fn clone(&mut self) -> Result<Box<dyn NotificationService>, ()> {
+		unimplemented!("clonable `NotificationService` not supported by `litep2p`");
+	}
+
+	/// Get protocol name of the `NotificationService`.
+	fn protocol(&self) -> &ProtocolName {
+		&self.protocol
+	}
+
+	/// Get message sink of the peer.
+	fn message_sink(&self, peer: &PeerId) -> Option<Box<dyn MessageSink>> {
+		self.handle.notification_sink(peer.into()).map(|sink| {
+			let sink: Box<dyn MessageSink> = Box::new(Litep2pMessageSink::new(
+				*peer,
+				self.protocol.clone(),
+				sink,
+				self.metrics.clone(),
+			));
+			sink
+		})
+	}
+
+	/// Get next event from the `Notifications` event stream.
+	async fn next_event(&mut self) -> Option<BizinikiwiNotificationEvent> {
+		loop {
+			tokio::select! {
+				biased;
+
+				event = self.handle.next() => match event? {
+					NotificationEvent::ValidateSubstream { peer, handshake, .. } => {
+						if let ValidationResult::Reject = self.peerset.report_inbound_substream(peer.into()) {
+							self.handle.send_validation_result(peer, Litep2pValidationResult::Reject);
+							continue;
+						}
+
+						let (tx, rx) = oneshot::channel();
+						self.pending_validations.push(Box::pin(async move { (peer.into(), rx.await) }));
+
+						log::trace!(target: LOG_TARGET, "{}: validate substream for {peer:?}", self.protocol);
+
+						return Some(BizinikiwiNotificationEvent::ValidateInboundSubstream {
+							peer: peer.into(),
+							handshake,
+							result_tx: tx,
+						});
+					}
+					NotificationEvent::NotificationStreamOpened {
+						peer,
+						fallback,
+						handshake,
+						direction,
+						..
+					} => {
+						self.metrics.register_substream_opened(&self.protocol);
+
+						match self.peerset.report_substream_opened(peer.into(), direction.into()) {
+							OpenResult::Reject => {
+								let _ = self.handle.close_substream_batch(vec![peer].into_iter().map(From::from)).await;
+								self.pending_cancels.insert(peer);
+
+								continue
+							}
+							OpenResult::Accept { direction } => {
+								log::trace!(target: LOG_TARGET, "{}: substream opened for {peer:?}", self.protocol);
+
+								return Some(BizinikiwiNotificationEvent::NotificationStreamOpened {
+									peer: peer.into(),
+									handshake,
+									direction,
+									negotiated_fallback: fallback.map(From::from),
+								});
+							}
+						}
+					}
+					NotificationEvent::NotificationStreamClosed {
+						peer,
+					} => {
+						log::trace!(target: LOG_TARGET, "{}: substream closed for {peer:?}", self.protocol);
+
+						self.metrics.register_substream_closed(&self.protocol);
+						self.peerset.report_substream_closed(peer.into());
+
+						if self.pending_cancels.remove(&peer) {
+							log::debug!(
+								target: LOG_TARGET,
+								"{}: substream closed to canceled peer ({peer:?})",
+								self.protocol
+							);
+							continue
+						}
+
+						return Some(BizinikiwiNotificationEvent::NotificationStreamClosed { peer: peer.into() })
+					}
+					NotificationEvent::NotificationStreamOpenFailure {
+						peer,
+						error,
+					} => {
+						log::trace!(target: LOG_TARGET, "{}: open failure for {peer:?}", self.protocol);
+						self.peerset.report_substream_open_failure(peer.into(), error);
+					}
+					NotificationEvent::NotificationReceived {
+						peer,
+						notification,
+					} => {
+						self.metrics.register_notification_received(&self.protocol, notification.len());
+
+						if !self.pending_cancels.contains(&peer) {
+							return Some(BizinikiwiNotificationEvent::NotificationReceived {
+								peer: peer.into(),
+								notification: notification.to_vec(),
+							});
+						}
+					}
+				},
+				result = self.pending_validations.next(), if !self.pending_validations.is_empty() => {
+					let (peer, result) = result?;
+					let validation_result = match result {
+						Ok(ValidationResult::Accept) => Litep2pValidationResult::Accept,
+						_ => {
+							self.peerset.report_substream_rejected(peer);
+							Litep2pValidationResult::Reject
+						}
+					};
+
+					self.handle.send_validation_result(peer.into(), validation_result);
+				}
+				command = self.peerset.next() => self.on_peerset_command(command?).await,
+			}
+		}
+	}
+}

bizinikiwi/client/network/src/litep2p/shim/notification/tests/fuzz.rs

@@ -0,0 +1,383 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Fuzz test emulates network events and peer connection handling by `Peerset`
+//! and `PeerStore` to discover possible inconsistencies in peer management.
+
+use crate::{
+	litep2p::{
+		peerstore::Peerstore,
+		shim::notification::peerset::{OpenResult, Peerset, PeersetCommand},
+	},
+	service::traits::{Direction, PeerStore, ValidationResult},
+	ProtocolName,
+};
+
+use futures::{FutureExt, StreamExt};
+use litep2p::protocol::notification::NotificationError;
+use rand::{
+	distributions::{Distribution, Uniform, WeightedIndex},
+	seq::IteratorRandom,
+};
+
+use pezsc_network_common::types::ReputationChange;
+use pezsc_network_types::PeerId;
+
+use std::{
+	collections::{HashMap, HashSet},
+	sync::Arc,
+};
+
+#[tokio::test]
+#[cfg(debug_assertions)]
+async fn run() {
+	pezsp_tracing::try_init_simple();
+
+	for _ in 0..50 {
+		test_once().await;
+	}
+}
+
+#[cfg(debug_assertions)]
+async fn test_once() {
+	// PRNG to use.
+	let mut rng = rand::thread_rng();
+
+	// peers that the peerset knows about.
+	let mut known_peers = HashSet::<PeerId>::new();
+
+	// peers that we have reserved. Always a subset of `known_peers`.
+	let mut reserved_peers = HashSet::<PeerId>::new();
+
+	// reserved only mode
+	let mut reserved_only = Uniform::new_inclusive(0, 10).sample(&mut rng) == 0;
+
+	// Bootnodes for `PeerStore` initialization.
+	let bootnodes = (0..Uniform::new_inclusive(0, 4).sample(&mut rng))
+		.map(|_| {
+			let id = PeerId::random();
+			known_peers.insert(id);
+			id
+		})
+		.collect();
+
+	let peerstore = Peerstore::new(bootnodes, None);
+	let peer_store_handle = peerstore.handle();
+
+	let (mut peerset, to_peerset) = Peerset::new(
+		ProtocolName::from("/notif/1"),
+		Uniform::new_inclusive(0, 25).sample(&mut rng),
+		Uniform::new_inclusive(0, 25).sample(&mut rng),
+		reserved_only,
+		(0..Uniform::new_inclusive(0, 2).sample(&mut rng))
+			.map(|_| {
+				let id = PeerId::random();
+				known_peers.insert(id);
+				reserved_peers.insert(id);
+				id
+			})
+			.collect(),
+		Default::default(),
+		Arc::clone(&peer_store_handle),
+	);
+
+	tokio::spawn(peerstore.run());
+
+	// opening substreams
+	let mut opening = HashMap::<PeerId, Direction>::new();
+
+	// open substreams
+	let mut open = HashMap::<PeerId, Direction>::new();
+
+	// closing substreams
+	let mut closing = HashSet::<PeerId>::new();
+
+	// closed substreams
+	let mut closed = HashSet::<PeerId>::new();
+
+	// perform a certain number of actions while checking that the state is consistent.
+	//
+	// if we reach the end of the loop, the run has succeeded
+	let _ = tokio::task::spawn_blocking(move || {
+		// PRNG to use in `spawn_blocking` context.
+		let mut rng = rand::thread_rng();
+
+		for _ in 0..2500 {
+			// each of these weights corresponds to an action that we may perform
+			let action_weights =
+				[300, 110, 110, 110, 110, 90, 70, 30, 110, 110, 110, 110, 20, 110, 50, 110];
+
+			match WeightedIndex::new(&action_weights).unwrap().sample(&mut rng) {
+				0 => match peerset.next().now_or_never() {
+					Some(Some(command)) => {
+						// open substreams to `peers`
+						for peer in command.open_peers {
+							opening.insert(peer, Direction::Outbound);
+							closed.remove(&peer);
+
+							assert!(!closing.contains(&peer));
+							assert!(!open.contains_key(&peer));
+						}
+
+						// close substreams to `peers`
+						for peer in command.close_peers {
+							assert!(closing.insert(peer));
+							assert!(open.remove(&peer).is_some());
+							assert!(!opening.contains_key(&peer));
+						}
+					},
+					Some(None) => panic!("peerset exited"),
+					None => {},
+				},
+				// get inbound connection from an unknown peer
+				1 => {
+					let new_peer = PeerId::random();
+					peer_store_handle.add_known_peer(new_peer);
+
+					match peerset.report_inbound_substream(new_peer) {
+						ValidationResult::Accept => {
+							opening.insert(new_peer, Direction::Inbound);
+						},
+						ValidationResult::Reject => {},
+					}
+				},
+				// substream opened successfully
+				//
+				// remove peer from `opening` (which contains its direction), report the open
+				// substream to `Peerset` and move peer state to `open`.
+				//
+				// if the substream was canceled while it was opening, move peer to `closing`
+				2 =>
+					if let Some(peer) = opening.keys().choose(&mut rng).copied() {
+						let direction = opening.remove(&peer).unwrap();
+						match peerset.report_substream_opened(peer, direction) {
+							OpenResult::Accept { .. } => {
+								assert!(open.insert(peer, direction).is_none());
+							},
+							OpenResult::Reject => {
+								assert!(closing.insert(peer));
+							},
+						}
+					},
+				// substream failed to open
+				3 =>
+					if let Some(peer) = opening.keys().choose(&mut rng).copied() {
+						let _ = opening.remove(&peer).unwrap();
+						peerset.report_substream_open_failure(peer, NotificationError::Rejected);
+					},
+				// substream was closed by remote peer
+				4 =>
+					if let Some(peer) = open.keys().choose(&mut rng).copied() {
+						let _ = open.remove(&peer).unwrap();
+						peerset.report_substream_closed(peer);
+						assert!(closed.insert(peer));
+					},
+				// substream was closed by local node
+				5 =>
+					if let Some(peer) = closing.iter().choose(&mut rng).copied() {
+						assert!(closing.remove(&peer));
+						assert!(closed.insert(peer));
+						peerset.report_substream_closed(peer);
+					},
+				// random connected peer was disconnected by the protocol
+				6 =>
+					if let Some(peer) = open.keys().choose(&mut rng).copied() {
+						to_peerset.unbounded_send(PeersetCommand::DisconnectPeer { peer }).unwrap();
+					},
+				// ban random peer
+				7 =>
+					if let Some(peer) = known_peers.iter().choose(&mut rng).copied() {
+						peer_store_handle.report_peer(peer, ReputationChange::new_fatal(""));
+					},
+				// inbound substream is received for a peer that was considered
+				// outbound
+				8 => {
+					let outbound_peers = opening
+						.iter()
+						.filter_map(|(peer, direction)| {
+							std::matches!(direction, Direction::Outbound).then_some(*peer)
+						})
+						.collect::<HashSet<_>>();
+
+					if let Some(peer) = outbound_peers.iter().choose(&mut rng).copied() {
+						match peerset.report_inbound_substream(peer) {
+							ValidationResult::Accept => {
+								opening.insert(peer, Direction::Inbound);
+							},
+							ValidationResult::Reject => {},
+						}
+					}
+				},
+				// set reserved peers
+				//
+				// choose peers from all available sets (open, opening, closing, closed) + some new
+				// peers
+				9 => {
+					let num_open = Uniform::new_inclusive(0, open.len()).sample(&mut rng);
+					let num_opening = Uniform::new_inclusive(0, opening.len()).sample(&mut rng);
+					let num_closing = Uniform::new_inclusive(0, closing.len()).sample(&mut rng);
+					let num_closed = Uniform::new_inclusive(0, closed.len()).sample(&mut rng);
+
+					let peers = open
+						.keys()
+						.copied()
+						.choose_multiple(&mut rng, num_open)
+						.into_iter()
+						.chain(
+							opening
+								.keys()
+								.copied()
+								.choose_multiple(&mut rng, num_opening)
+								.into_iter(),
+						)
+						.chain(
+							closing
+								.iter()
+								.copied()
+								.choose_multiple(&mut rng, num_closing)
+								.into_iter(),
+						)
+						.chain(
+							closed
+								.iter()
+								.copied()
+								.choose_multiple(&mut rng, num_closed)
+								.into_iter(),
+						)
+						.chain((0..5).map(|_| {
+							let peer = PeerId::random();
+							known_peers.insert(peer);
+							peer_store_handle.add_known_peer(peer);
+							peer
+						}))
+						.filter(|peer| !reserved_peers.contains(peer))
+						.collect::<HashSet<_>>();
+
+					reserved_peers.extend(peers.clone().into_iter());
+					to_peerset.unbounded_send(PeersetCommand::SetReservedPeers { peers }).unwrap();
+				},
+				// add reserved peers
+				10 => {
+					let num_open = Uniform::new_inclusive(0, open.len()).sample(&mut rng);
+					let num_opening = Uniform::new_inclusive(0, opening.len()).sample(&mut rng);
+					let num_closing = Uniform::new_inclusive(0, closing.len()).sample(&mut rng);
+					let num_closed = Uniform::new_inclusive(0, closed.len()).sample(&mut rng);
+
+					let peers = open
+						.keys()
+						.copied()
+						.choose_multiple(&mut rng, num_open)
+						.into_iter()
+						.chain(
+							opening
+								.keys()
+								.copied()
+								.choose_multiple(&mut rng, num_opening)
+								.into_iter(),
+						)
+						.chain(
+							closing
+								.iter()
+								.copied()
+								.choose_multiple(&mut rng, num_closing)
+								.into_iter(),
+						)
+						.chain(
+							closed
+								.iter()
+								.copied()
+								.choose_multiple(&mut rng, num_closed)
+								.into_iter(),
+						)
+						.chain((0..5).map(|_| {
+							let peer = PeerId::random();
+							known_peers.insert(peer);
+							peer_store_handle.add_known_peer(peer);
+							peer
+						}))
+						.filter(|peer| !reserved_peers.contains(peer))
+						.collect::<HashSet<_>>();
+
+					reserved_peers.extend(peers.clone().into_iter());
+					to_peerset.unbounded_send(PeersetCommand::AddReservedPeers { peers }).unwrap();
+				},
+				// remove reserved peers
+				11 => {
+					let num_to_remove =
+						Uniform::new_inclusive(0, reserved_peers.len()).sample(&mut rng);
+					let peers = reserved_peers
+						.iter()
+						.copied()
+						.choose_multiple(&mut rng, num_to_remove)
+						.into_iter()
+						.collect::<HashSet<_>>();
+
+					peers.iter().for_each(|peer| {
+						assert!(reserved_peers.remove(peer));
+					});
+
+					to_peerset
+						.unbounded_send(PeersetCommand::RemoveReservedPeers { peers })
+						.unwrap();
+				},
+				// set reserved only
+				12 => {
+					reserved_only = !reserved_only;
+
+					let _ = to_peerset
+						.unbounded_send(PeersetCommand::SetReservedOnly { reserved_only });
+				},
+				//
+				// discover a new node.
+				13 => {
+					let new_peer = PeerId::random();
+					known_peers.insert(new_peer);
+					peer_store_handle.add_known_peer(new_peer);
+				},
+				// protocol rejected a substream that was accepted by `Peerset`
+				14 => {
+					let inbound_peers = opening
+						.iter()
+						.filter_map(|(peer, direction)| {
+							std::matches!(direction, Direction::Inbound).then_some(*peer)
+						})
+						.collect::<HashSet<_>>();
+
+					if let Some(peer) = inbound_peers.iter().choose(&mut rng).copied() {
+						peerset.report_substream_rejected(peer);
+						opening.remove(&peer);
+					}
+				},
+				// inbound substream received for a peer in `closed`
+				15 =>
+					if let Some(peer) = closed.iter().choose(&mut rng).copied() {
+						match peerset.report_inbound_substream(peer) {
+							ValidationResult::Accept => {
+								assert!(closed.remove(&peer));
+								opening.insert(peer, Direction::Inbound);
+							},
+							ValidationResult::Reject => {},
+						}
+					},
+				_ => unreachable!(),
+			}
+		}
+	})
+	.await
+	.unwrap();
+}

bizinikiwi/client/network/src/litep2p/shim/notification/tests/mod.rs

@@ -0,0 +1,22 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+#[cfg(test)]
+mod fuzz;
+#[cfg(test)]
+mod peerset;

bizinikiwi/client/network/src/litep2p/shim/request_response/metrics.rs

@@ -0,0 +1,78 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Metrics for [`RequestResponseProtocol`](super::RequestResponseProtocol).
+
+use crate::{service::metrics::Metrics, types::ProtocolName};
+
+use std::time::Duration;
+
+/// Request-response metrics.
+pub struct RequestResponseMetrics {
+	/// Metrics.
+	metrics: Option<Metrics>,
+
+	/// Protocol name.
+	protocol: ProtocolName,
+}
+
+impl RequestResponseMetrics {
+	pub fn new(metrics: Option<Metrics>, protocol: ProtocolName) -> Self {
+		Self { metrics, protocol }
+	}
+
+	/// Register inbound request failure to Prometheus
+	pub fn register_inbound_request_failure(&self, reason: &str) {
+		if let Some(metrics) = &self.metrics {
+			metrics
+				.requests_in_failure_total
+				.with_label_values(&[&self.protocol, reason])
+				.inc();
+		}
+	}
+
+	/// Register inbound request success to Prometheus
+	pub fn register_inbound_request_success(&self, serve_time: Duration) {
+		if let Some(metrics) = &self.metrics {
+			metrics
+				.requests_in_success_total
+				.with_label_values(&[&self.protocol])
+				.observe(serve_time.as_secs_f64());
+		}
+	}
+
+	/// Register inbound request failure to Prometheus
+	pub fn register_outbound_request_failure(&self, reason: &str) {
+		if let Some(metrics) = &self.metrics {
+			metrics
+				.requests_out_failure_total
+				.with_label_values(&[&self.protocol, reason])
+				.inc();
+		}
+	}
+
+	/// Register inbound request success to Prometheus
+	pub fn register_outbound_request_success(&self, duration: Duration) {
+		if let Some(metrics) = &self.metrics {
+			metrics
+				.requests_out_success_total
+				.with_label_values(&[&self.protocol])
+				.observe(duration.as_secs_f64());
+		}
+	}
+}

bizinikiwi/client/network/src/litep2p/shim/request_response/mod.rs

@@ -0,0 +1,568 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Shim for litep2p's request-response implementation to make it work with `pezsc_network`'s
+//! request-response API.
+
+use crate::{
+	litep2p::shim::request_response::metrics::RequestResponseMetrics,
+	peer_store::PeerStoreProvider,
+	request_responses::{IncomingRequest, OutgoingResponse},
+	service::{metrics::Metrics, traits::RequestResponseConfig as RequestResponseConfigT},
+	IfDisconnected, OutboundFailure, ProtocolName, RequestFailure,
+};
+
+use futures::{channel::oneshot, future::BoxFuture, stream::FuturesUnordered, StreamExt};
+use litep2p::{
+	error::{ImmediateDialError, NegotiationError, SubstreamError},
+	protocol::request_response::{
+		DialOptions, RejectReason, RequestResponseError, RequestResponseEvent,
+		RequestResponseHandle,
+	},
+	types::RequestId,
+};
+
+use pezsc_network_types::PeerId;
+use pezsc_utils::mpsc::{TracingUnboundedReceiver, TracingUnboundedSender};
+
+use std::{
+	collections::HashMap,
+	sync::Arc,
+	time::{Duration, Instant},
+};
+
+mod metrics;
+
+#[cfg(test)]
+mod tests;
+
+/// Logging target for the file.
+const LOG_TARGET: &str = "sub-libp2p::request-response";
+
+/// Type containing information related to an outbound request.
+#[derive(Debug)]
+pub struct OutboundRequest {
+	/// Peer ID.
+	peer: PeerId,
+
+	/// Request.
+	request: Vec<u8>,
+
+	/// Fallback request, if provided.
+	fallback_request: Option<(Vec<u8>, ProtocolName)>,
+
+	/// `oneshot::Sender` for sending the received response, or failure.
+	sender: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+
+	/// What should the node do if `peer` is disconnected.
+	dial_behavior: IfDisconnected,
+}
+
+impl OutboundRequest {
+	/// Create new [`OutboundRequest`].
+	pub fn new(
+		peer: PeerId,
+		request: Vec<u8>,
+		sender: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+		dial_behavior: IfDisconnected,
+	) -> Self {
+		OutboundRequest { peer, request, sender, fallback_request, dial_behavior }
+	}
+}
+
+/// Pending request.
+struct PendingRequest {
+	tx: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+	started: Instant,
+	fallback_request: Option<(Vec<u8>, ProtocolName)>,
+}
+
+impl PendingRequest {
+	/// Create new [`PendingRequest`].
+	fn new(
+		tx: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+		started: Instant,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+	) -> Self {
+		Self { tx, started, fallback_request }
+	}
+}
+
+/// Request-response protocol configuration.
+///
+/// See [`RequestResponseConfiguration`](crate::request_response::ProtocolConfig) for more details.
+#[derive(Debug)]
+pub struct RequestResponseConfig {
+	/// Name of the protocol on the wire. Should be something like `/foo/bar`.
+	pub protocol_name: ProtocolName,
+
+	/// Fallback on the wire protocol names to support.
+	pub fallback_names: Vec<ProtocolName>,
+
+	/// Maximum allowed size, in bytes, of a request.
+	pub max_request_size: u64,
+
+	/// Maximum allowed size, in bytes, of a response.
+	pub max_response_size: u64,
+
+	/// Duration after which emitted requests are considered timed out.
+	pub request_timeout: Duration,
+
+	/// Channel on which the networking service will send incoming requests.
+	pub inbound_queue: Option<async_channel::Sender<IncomingRequest>>,
+}
+
+impl RequestResponseConfig {
+	/// Create new [`RequestResponseConfig`].
+	pub(crate) fn new(
+		protocol_name: ProtocolName,
+		fallback_names: Vec<ProtocolName>,
+		max_request_size: u64,
+		max_response_size: u64,
+		request_timeout: Duration,
+		inbound_queue: Option<async_channel::Sender<IncomingRequest>>,
+	) -> Self {
+		Self {
+			protocol_name,
+			fallback_names,
+			max_request_size,
+			max_response_size,
+			request_timeout,
+			inbound_queue,
+		}
+	}
+}
+
+impl RequestResponseConfigT for RequestResponseConfig {
+	fn protocol_name(&self) -> &ProtocolName {
+		&self.protocol_name
+	}
+}
+
+/// Request-response protocol.
+///
+/// This is slightly different from the `RequestResponsesBehaviour` in that it is protocol-specific,
+/// meaning there is an instance of `RequestResponseProtocol` for each installed request-response
+/// protocol and that instance deals only with the requests and responses of that protocol, nothing
+/// else. It also differs from the other implementation by combining both inbound and outbound
+/// requests under one instance so all request-response-related behavior of any given protocol is
+/// handled through one instance of `RequestResponseProtocol`.
+pub struct RequestResponseProtocol {
+	/// Protocol name.
+	protocol: ProtocolName,
+
+	/// Handle to request-response protocol.
+	handle: RequestResponseHandle,
+
+	/// Inbound queue for sending received requests to protocol implementation in Pezkuwi SDK.
+	inbound_queue: Option<async_channel::Sender<IncomingRequest>>,
+
+	/// Handle to `Peerstore`.
+	peerstore_handle: Arc<dyn PeerStoreProvider>,
+
+	/// Pending responses.
+	pending_inbound_responses: HashMap<RequestId, PendingRequest>,
+
+	/// Pending outbound responses.
+	pending_outbound_responses: FuturesUnordered<
+		BoxFuture<'static, (litep2p::PeerId, RequestId, Result<OutgoingResponse, ()>, Instant)>,
+	>,
+
+	/// RX channel for receiving info for outbound requests.
+	request_rx: TracingUnboundedReceiver<OutboundRequest>,
+
+	/// Map of supported request-response protocols which are used to support fallback requests.
+	///
+	/// If negotiation for the main protocol fails and the request was sent with a fallback,
+	/// [`RequestResponseProtocol`] queries this map and sends the request that protocol for
+	/// processing.
+	request_tx: HashMap<ProtocolName, TracingUnboundedSender<OutboundRequest>>,
+
+	/// Metrics, if enabled.
+	metrics: RequestResponseMetrics,
+}
+
+impl RequestResponseProtocol {
+	/// Create new [`RequestResponseProtocol`].
+	pub fn new(
+		protocol: ProtocolName,
+		handle: RequestResponseHandle,
+		peerstore_handle: Arc<dyn PeerStoreProvider>,
+		inbound_queue: Option<async_channel::Sender<IncomingRequest>>,
+		request_rx: TracingUnboundedReceiver<OutboundRequest>,
+		request_tx: HashMap<ProtocolName, TracingUnboundedSender<OutboundRequest>>,
+		metrics: Option<Metrics>,
+	) -> Self {
+		Self {
+			handle,
+			request_rx,
+			request_tx,
+			inbound_queue,
+			peerstore_handle,
+			protocol: protocol.clone(),
+			pending_inbound_responses: HashMap::new(),
+			pending_outbound_responses: FuturesUnordered::new(),
+			metrics: RequestResponseMetrics::new(metrics, protocol),
+		}
+	}
+
+	/// Send `request` to `peer`.
+	async fn on_send_request(
+		&mut self,
+		peer: PeerId,
+		request: Vec<u8>,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+		tx: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+		connect: IfDisconnected,
+	) {
+		let dial_options = match connect {
+			IfDisconnected::TryConnect => DialOptions::Dial,
+			IfDisconnected::ImmediateError => DialOptions::Reject,
+		};
+
+		log::trace!(
+			target: LOG_TARGET,
+			"{}: send request to {:?} (fallback {:?}) (dial options: {:?})",
+			self.protocol,
+			peer,
+			fallback_request,
+			dial_options,
+		);
+
+		match self.handle.try_send_request(peer.into(), request, dial_options) {
+			Ok(request_id) => {
+				self.pending_inbound_responses
+					.insert(request_id, PendingRequest::new(tx, Instant::now(), fallback_request));
+			},
+			Err(error) => {
+				log::warn!(
+					target: LOG_TARGET,
+					"{}: failed to send request to {peer:?}: {error:?}",
+					self.protocol,
+				);
+
+				let _ = tx.send(Err(RequestFailure::Refused));
+				self.metrics.register_inbound_request_failure(error.to_string().as_ref());
+			},
+		}
+	}
+
+	/// Handle inbound request from `peer`
+	///
+	/// If the protocol is configured outbound only, reject the request immediately.
+	fn on_inbound_request(
+		&mut self,
+		peer: litep2p::PeerId,
+		fallback: Option<litep2p::ProtocolName>,
+		request_id: RequestId,
+		request: Vec<u8>,
+	) {
+		log::trace!(
+			target: LOG_TARGET,
+			"{}: request received from {peer:?} ({fallback:?} {request_id:?}), request size {:?}",
+			self.protocol,
+			request.len(),
+		);
+
+		let Some(inbound_queue) = &self.inbound_queue else {
+			log::trace!(
+				target: LOG_TARGET,
+				"{}: rejecting inbound request from {peer:?}, protocol configured as outbound only",
+				self.protocol,
+			);
+
+			self.handle.reject_request(request_id);
+			return;
+		};
+
+		if self.peerstore_handle.is_banned(&peer.into()) {
+			log::trace!(
+				target: LOG_TARGET,
+				"{}: rejecting inbound request from banned {peer:?} ({request_id:?})",
+				self.protocol,
+			);
+
+			self.handle.reject_request(request_id);
+			self.metrics.register_inbound_request_failure("banned-peer");
+			return;
+		}
+
+		let (tx, rx) = oneshot::channel();
+
+		match inbound_queue.try_send(IncomingRequest {
+			peer: peer.into(),
+			payload: request,
+			pending_response: tx,
+		}) {
+			Ok(_) => {
+				self.pending_outbound_responses.push(Box::pin(async move {
+					(peer, request_id, rx.await.map_err(|_| ()), Instant::now())
+				}));
+			},
+			Err(error) => {
+				log::trace!(
+					target: LOG_TARGET,
+					"{:?}: dropping request from {peer:?} ({request_id:?}), inbound queue full",
+					self.protocol,
+				);
+
+				self.handle.reject_request(request_id);
+				self.metrics.register_inbound_request_failure(error.to_string().as_ref());
+			},
+		}
+	}
+
+	/// Handle received inbound response.
+	fn on_inbound_response(
+		&mut self,
+		peer: litep2p::PeerId,
+		request_id: RequestId,
+		_fallback: Option<litep2p::ProtocolName>,
+		response: Vec<u8>,
+	) {
+		match self.pending_inbound_responses.remove(&request_id) {
+			None => log::warn!(
+				target: LOG_TARGET,
+				"{:?}: response received for {peer:?} but {request_id:?} doesn't exist",
+				self.protocol,
+			),
+			Some(PendingRequest { tx, started, .. }) => {
+				log::trace!(
+					target: LOG_TARGET,
+					"{:?}: response received for {peer:?} ({request_id:?}), response size {:?}",
+					self.protocol,
+					response.len(),
+				);
+
+				let _ = tx.send(Ok((response, self.protocol.clone())));
+				self.metrics.register_outbound_request_success(started.elapsed());
+			},
+		}
+	}
+
+	/// Handle failed outbound request.
+	fn on_request_failed(
+		&mut self,
+		peer: litep2p::PeerId,
+		request_id: RequestId,
+		error: RequestResponseError,
+	) {
+		log::debug!(
+			target: LOG_TARGET,
+			"{:?}: request failed for {peer:?} ({request_id:?}): {error:?}",
+			self.protocol
+		);
+
+		let Some(PendingRequest { tx, fallback_request, .. }) =
+			self.pending_inbound_responses.remove(&request_id)
+		else {
+			log::warn!(
+				target: LOG_TARGET,
+				"{:?}: request failed for peer {peer:?} but {request_id:?} doesn't exist",
+				self.protocol,
+			);
+
+			return;
+		};
+
+		let status = match error {
+			RequestResponseError::NotConnected =>
+				Some((RequestFailure::NotConnected, "not-connected")),
+			RequestResponseError::Rejected(reason) => {
+				let reason = match reason {
+					RejectReason::ConnectionClosed => "connection-closed",
+					RejectReason::SubstreamClosed => "substream-closed",
+					RejectReason::SubstreamOpenError(substream_error) => match substream_error {
+						SubstreamError::NegotiationError(NegotiationError::Timeout) =>
+							"substream-timeout",
+						_ => "substream-open-error",
+					},
+					RejectReason::DialFailed(None) => "dial-failed",
+					RejectReason::DialFailed(Some(ImmediateDialError::AlreadyConnected)) =>
+						"dial-already-connected",
+					RejectReason::DialFailed(Some(ImmediateDialError::PeerIdMissing)) =>
+						"dial-peerid-missing",
+					RejectReason::DialFailed(Some(ImmediateDialError::TriedToDialSelf)) =>
+						"dial-tried-to-dial-self",
+					RejectReason::DialFailed(Some(ImmediateDialError::NoAddressAvailable)) =>
+						"dial-no-address-available",
+					RejectReason::DialFailed(Some(ImmediateDialError::TaskClosed)) =>
+						"dial-task-closed",
+					RejectReason::DialFailed(Some(ImmediateDialError::ChannelClogged)) =>
+						"dial-channel-clogged",
+				};
+
+				Some((RequestFailure::Refused, reason))
+			},
+			RequestResponseError::Timeout =>
+				Some((RequestFailure::Network(OutboundFailure::Timeout), "timeout")),
+			RequestResponseError::Canceled => {
+				log::debug!(
+					target: LOG_TARGET,
+					"{}: request canceled by local node to {peer:?} ({request_id:?})",
+					self.protocol,
+				);
+				None
+			},
+			RequestResponseError::TooLargePayload => {
+				log::warn!(
+					target: LOG_TARGET,
+					"{}: tried to send too large request to {peer:?} ({request_id:?})",
+					self.protocol,
+				);
+				Some((RequestFailure::Refused, "payload-too-large"))
+			},
+			RequestResponseError::UnsupportedProtocol => match fallback_request {
+				Some((request, protocol)) => match self.request_tx.get(&protocol) {
+					Some(sender) => {
+						log::debug!(
+							target: LOG_TARGET,
+							"{}: failed to negotiate protocol with {:?}. Trying the fallback protocol ({})",
+							self.protocol,
+							peer,
+							protocol,
+						);
+
+						let outbound_request = OutboundRequest::new(
+							peer.into(),
+							request,
+							tx,
+							None,
+							IfDisconnected::ImmediateError,
+						);
+
+						// since remote peer doesn't support the main protocol (`self.protocol`),
+						// try to send the request over a fallback protocol by creating a new
+						// `OutboundRequest` from the original data, now with the fallback request
+						// payload, and send it over to the (fallback) request handler like it was
+						// a normal request.
+						let _ = sender.unbounded_send(outbound_request);
+
+						return;
+					},
+					None => {
+						log::warn!(
+							target: LOG_TARGET,
+							"{}: fallback request provided but protocol ({}) doesn't exist (peer {:?})",
+							self.protocol,
+							protocol,
+							peer,
+						);
+
+						Some((RequestFailure::Refused, "invalid-fallback-protocol"))
+					},
+				},
+				None => Some((RequestFailure::Refused, "unsupported-protocol")),
+			},
+		};
+
+		if let Some((error, reason)) = status {
+			self.metrics.register_outbound_request_failure(reason);
+			let _ = tx.send(Err(error));
+		}
+	}
+
+	/// Handle outbound response.
+	fn on_outbound_response(
+		&mut self,
+		peer: litep2p::PeerId,
+		request_id: RequestId,
+		response: OutgoingResponse,
+		started: Instant,
+	) {
+		let OutgoingResponse { result, reputation_changes, sent_feedback } = response;
+
+		for change in reputation_changes {
+			log::trace!(target: LOG_TARGET, "{}: report {peer:?}: {change:?}", self.protocol);
+			self.peerstore_handle.report_peer(peer.into(), change);
+		}
+
+		match result {
+			Err(()) => {
+				log::debug!(
+					target: LOG_TARGET,
+					"{}: response rejected ({request_id:?}) for {peer:?}",
+					self.protocol,
+				);
+
+				self.handle.reject_request(request_id);
+				self.metrics.register_inbound_request_failure("rejected");
+			},
+			Ok(response) => {
+				log::trace!(
+					target: LOG_TARGET,
+					"{}: send response ({request_id:?}) to {peer:?}, response size {}",
+					self.protocol,
+					response.len(),
+				);
+
+				match sent_feedback {
+					None => self.handle.send_response(request_id, response),
+					Some(feedback) =>
+						self.handle.send_response_with_feedback(request_id, response, feedback),
+				}
+
+				self.metrics.register_inbound_request_success(started.elapsed());
+			},
+		}
+	}
+
+	/// Start running event loop of the request-response protocol.
+	pub async fn run(mut self) {
+		loop {
+			tokio::select! {
+				event = self.handle.next() => match event {
+					None => return,
+					Some(RequestResponseEvent::RequestReceived {
+						peer,
+						fallback,
+						request_id,
+						request,
+					}) => self.on_inbound_request(peer, fallback, request_id, request),
+					Some(RequestResponseEvent::ResponseReceived { peer, request_id, fallback, response }) => {
+						self.on_inbound_response(peer, request_id, fallback, response);
+					},
+					Some(RequestResponseEvent::RequestFailed { peer, request_id, error }) => {
+						self.on_request_failed(peer, request_id, error);
+					},
+				},
+				event = self.pending_outbound_responses.next(), if !self.pending_outbound_responses.is_empty() => match event {
+					None => return,
+					Some((peer, request_id, Err(()), _)) => {
+						log::debug!(target: LOG_TARGET, "{}: reject request ({request_id:?}) from {peer:?}", self.protocol);
+
+						self.handle.reject_request(request_id);
+						self.metrics.register_inbound_request_failure("rejected");
+					}
+					Some((peer, request_id, Ok(response), started)) => {
+						self.on_outbound_response(peer, request_id, response, started);
+					}
+				},
+				event = self.request_rx.next() => match event {
+					None => return,
+					Some(outbound_request) => {
+						let OutboundRequest { peer, request, sender, dial_behavior, fallback_request } = outbound_request;
+
+						self.on_send_request(peer, request, fallback_request, sender, dial_behavior).await;
+					}
+				}
+			}
+		}
+	}
+}

bizinikiwi/client/network/src/litep2p/shim/request_response/tests.rs

@@ -0,0 +1,906 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::{
+	litep2p::{
+		peerstore::peerstore_handle_test,
+		shim::request_response::{OutboundRequest, RequestResponseProtocol},
+	},
+	request_responses::{IfDisconnected, IncomingRequest, OutgoingResponse},
+	ProtocolName, RequestFailure,
+};
+
+use futures::{channel::oneshot, StreamExt};
+use litep2p::{
+	config::ConfigBuilder as Litep2pConfigBuilder,
+	protocol::request_response::{
+		ConfigBuilder, DialOptions, RequestResponseError, RequestResponseEvent,
+		RequestResponseHandle,
+	},
+	transport::tcp::config::Config as TcpConfig,
+	Litep2p, Litep2pEvent,
+};
+
+use pezsc_network_types::PeerId;
+use pezsc_utils::mpsc::tracing_unbounded;
+
+use std::{collections::HashMap, sync::Arc, task::Poll};
+
+/// Create `litep2p` for testing.
+async fn make_litep2p() -> (Litep2p, RequestResponseHandle) {
+	let (config, handle) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/1"))
+		.with_max_size(1024)
+		.build();
+
+	(
+		Litep2p::new(
+			Litep2pConfigBuilder::new()
+				.with_request_response_protocol(config)
+				.with_tcp(TcpConfig {
+					listen_addresses: vec![
+						"/ip4/0.0.0.0/tcp/0".parse().unwrap(),
+						"/ip6/::/tcp/0".parse().unwrap(),
+					],
+					..Default::default()
+				})
+				.build(),
+		)
+		.unwrap(),
+		handle,
+	)
+}
+
+// connect two `litep2p` instances together
+async fn connect_peers(litep2p1: &mut Litep2p, litep2p2: &mut Litep2p) {
+	let address = litep2p2.listen_addresses().next().unwrap().clone();
+	litep2p1.dial_address(address).await.unwrap();
+
+	let mut litep2p1_connected = false;
+	let mut litep2p2_connected = false;
+
+	loop {
+		tokio::select! {
+			event = litep2p1.next_event() => match event.unwrap() {
+				Litep2pEvent::ConnectionEstablished { .. } => {
+					litep2p1_connected = true;
+				}
+				_ => {},
+			},
+			event = litep2p2.next_event() => match event.unwrap() {
+				Litep2pEvent::ConnectionEstablished { .. } => {
+					litep2p2_connected = true;
+				}
+				_ => {},
+			}
+		}
+
+		if litep2p1_connected && litep2p2_connected {
+			break;
+		}
+	}
+}
+
+#[tokio::test]
+async fn dial_failure() {
+	let (mut litep2p, handle) = make_litep2p().await;
+	let (tx, _rx) = async_channel::bounded(64);
+	let (outbound_tx, outbound_rx) = tracing_unbounded("outbound-request", 1000);
+	let senders = HashMap::from_iter([(ProtocolName::from("/protocol/1"), outbound_tx.clone())]);
+
+	let protocol = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle,
+		Arc::new(peerstore_handle_test()),
+		Some(tx),
+		outbound_rx,
+		senders,
+		None,
+	);
+
+	tokio::spawn(protocol.run());
+	tokio::spawn(async move { while let Some(_) = litep2p.next_event().await {} });
+
+	let peer = PeerId::random();
+	let (result_tx, result_rx) = oneshot::channel();
+
+	outbound_tx
+		.unbounded_send(OutboundRequest {
+			peer,
+			request: vec![1, 2, 3, 4],
+			sender: result_tx,
+			fallback_request: None,
+			dial_behavior: IfDisconnected::TryConnect,
+		})
+		.unwrap();
+
+	assert!(std::matches!(result_rx.await, Ok(Err(RequestFailure::Refused))));
+}
+
+#[tokio::test]
+async fn send_request_to_disconnected_peer() {
+	let (mut litep2p, handle) = make_litep2p().await;
+	let (tx, _rx) = async_channel::bounded(64);
+	let (outbound_tx, outbound_rx) = tracing_unbounded("outbound-request", 1000);
+	let senders = HashMap::from_iter([(ProtocolName::from("/protocol/1"), outbound_tx.clone())]);
+
+	let protocol = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle,
+		Arc::new(peerstore_handle_test()),
+		Some(tx),
+		outbound_rx,
+		senders,
+		None,
+	);
+
+	tokio::spawn(protocol.run());
+	tokio::spawn(async move { while let Some(_) = litep2p.next_event().await {} });
+
+	let peer = PeerId::random();
+	let (result_tx, result_rx) = oneshot::channel();
+
+	outbound_tx
+		.unbounded_send(OutboundRequest {
+			peer,
+			request: vec![1, 2, 3, 4],
+			sender: result_tx,
+			fallback_request: None,
+			dial_behavior: IfDisconnected::ImmediateError,
+		})
+		.unwrap();
+
+	assert!(std::matches!(result_rx.await, Ok(Err(RequestFailure::NotConnected))));
+}
+
+#[tokio::test]
+async fn send_request_to_disconnected_peer_and_dial() {
+	let (mut litep2p1, handle1) = make_litep2p().await;
+	let (mut litep2p2, handle2) = make_litep2p().await;
+
+	let peer1 = *litep2p1.local_peer_id();
+	let peer2 = *litep2p2.local_peer_id();
+
+	litep2p1.add_known_address(
+		peer2,
+		std::iter::once(litep2p2.listen_addresses().next().expect("listen address").clone()),
+	);
+
+	let (outbound_tx1, outbound_rx1) = tracing_unbounded("outbound-request", 1000);
+	let senders = HashMap::from_iter([(ProtocolName::from("/protocol/1"), outbound_tx1.clone())]);
+	let (tx1, _rx1) = async_channel::bounded(64);
+
+	let protocol1 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle1,
+		Arc::new(peerstore_handle_test()),
+		Some(tx1),
+		outbound_rx1,
+		senders,
+		None,
+	);
+
+	let (outbound_tx2, outbound_rx2) = tracing_unbounded("outbound-request", 1000);
+	let senders = HashMap::from_iter([(ProtocolName::from("/protocol/1"), outbound_tx2)]);
+	let (tx2, rx2) = async_channel::bounded(64);
+
+	let protocol2 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle2,
+		Arc::new(peerstore_handle_test()),
+		Some(tx2),
+		outbound_rx2,
+		senders,
+		None,
+	);
+
+	tokio::spawn(protocol1.run());
+	tokio::spawn(protocol2.run());
+	tokio::spawn(async move { while let Some(_) = litep2p1.next_event().await {} });
+	tokio::spawn(async move { while let Some(_) = litep2p2.next_event().await {} });
+
+	let (result_tx, _result_rx) = oneshot::channel();
+	outbound_tx1
+		.unbounded_send(OutboundRequest {
+			peer: peer2.into(),
+			request: vec![1, 2, 3, 4],
+			sender: result_tx,
+			fallback_request: None,
+			dial_behavior: IfDisconnected::TryConnect,
+		})
+		.unwrap();
+
+	match rx2.recv().await {
+		Ok(IncomingRequest { peer, payload, .. }) => {
+			assert_eq!(peer, Into::<PeerId>::into(peer1));
+			assert_eq!(payload, vec![1, 2, 3, 4]);
+		},
+		Err(error) => panic!("unexpected error: {error:?}"),
+	}
+}
+
+#[tokio::test]
+async fn too_many_inbound_requests() {
+	let (mut litep2p1, handle1) = make_litep2p().await;
+	let (mut litep2p2, mut handle2) = make_litep2p().await;
+	let peer1 = *litep2p1.local_peer_id();
+
+	connect_peers(&mut litep2p1, &mut litep2p2).await;
+
+	let (outbound_tx, outbound_rx) = tracing_unbounded("outbound-request", 1000);
+	let senders = HashMap::from_iter([(ProtocolName::from("/protocol/1"), outbound_tx)]);
+	let (tx, _rx) = async_channel::bounded(4);
+
+	let protocol = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle1,
+		Arc::new(peerstore_handle_test()),
+		Some(tx),
+		outbound_rx,
+		senders,
+		None,
+	);
+
+	tokio::spawn(protocol.run());
+	tokio::spawn(async move { while let Some(_) = litep2p1.next_event().await {} });
+	tokio::spawn(async move { while let Some(_) = litep2p2.next_event().await {} });
+
+	// send 5 request and verify that one of the requests will fail
+	for _ in 0..5 {
+		handle2
+			.send_request(peer1, vec![1, 2, 3, 4], DialOptions::Reject)
+			.await
+			.unwrap();
+	}
+
+	// verify that one of the requests is rejected
+	match handle2.next().await {
+		Some(RequestResponseEvent::RequestFailed { peer, error, .. }) => {
+			assert_eq!(peer, peer1);
+			assert_eq!(
+				error,
+				RequestResponseError::Rejected(
+					litep2p::protocol::request_response::RejectReason::SubstreamClosed
+				)
+			);
+		},
+		event => panic!("inavlid event: {event:?}"),
+	}
+
+	// verify that no other events are read from the handle
+	futures::future::poll_fn(|cx| match handle2.poll_next_unpin(cx) {
+		Poll::Pending => Poll::Ready(()),
+		event => panic!("invalid event: {event:?}"),
+	})
+	.await;
+}
+
+#[tokio::test]
+async fn feedback_works() {
+	let (mut litep2p1, handle1) = make_litep2p().await;
+	let (mut litep2p2, mut handle2) = make_litep2p().await;
+
+	let peer1 = *litep2p1.local_peer_id();
+	let peer2 = *litep2p2.local_peer_id();
+
+	connect_peers(&mut litep2p1, &mut litep2p2).await;
+
+	let (outbound_tx, outbound_rx) = tracing_unbounded("outbound-request", 1000);
+	let senders = HashMap::from_iter([(ProtocolName::from("/protocol/1"), outbound_tx)]);
+	let (tx, rx) = async_channel::bounded(4);
+
+	let protocol = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle1,
+		Arc::new(peerstore_handle_test()),
+		Some(tx),
+		outbound_rx,
+		senders,
+		None,
+	);
+
+	tokio::spawn(protocol.run());
+	tokio::spawn(async move { while let Some(_) = litep2p1.next_event().await {} });
+	tokio::spawn(async move { while let Some(_) = litep2p2.next_event().await {} });
+
+	let request_id = handle2
+		.send_request(peer1, vec![1, 2, 3, 4], DialOptions::Reject)
+		.await
+		.unwrap();
+
+	let rx = match rx.recv().await {
+		Ok(IncomingRequest { peer, payload, pending_response }) => {
+			assert_eq!(peer, peer2.into());
+			assert_eq!(payload, vec![1, 2, 3, 4]);
+
+			let (tx, rx) = oneshot::channel();
+			pending_response
+				.send(OutgoingResponse {
+					result: Ok(vec![5, 6, 7, 8]),
+					reputation_changes: Vec::new(),
+					sent_feedback: Some(tx),
+				})
+				.unwrap();
+			rx
+		},
+		event => panic!("invalid event: {event:?}"),
+	};
+
+	match handle2.next().await {
+		Some(RequestResponseEvent::ResponseReceived {
+			peer,
+			request_id: received_id,
+			response,
+			..
+		}) => {
+			assert_eq!(peer, peer1);
+			assert_eq!(request_id, received_id);
+			assert_eq!(response, vec![5, 6, 7, 8]);
+			assert!(rx.await.is_ok());
+		},
+		event => panic!("invalid event: {event:?}"),
+	}
+}
+
+#[tokio::test]
+async fn fallback_request_compatible_peers() {
+	// `litep2p1` supports both the new and the old protocol
+	let (mut litep2p1, handle1_1, handle1_2) = {
+		let (config1, handle1) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/2"))
+			.with_max_size(1024)
+			.build();
+
+		let (config2, handle2) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/1"))
+			.with_max_size(1024)
+			.build();
+		(
+			Litep2p::new(
+				Litep2pConfigBuilder::new()
+					.with_request_response_protocol(config1)
+					.with_request_response_protocol(config2)
+					.with_tcp(TcpConfig {
+						listen_addresses: vec![
+							"/ip4/0.0.0.0/tcp/0".parse().unwrap(),
+							"/ip6/::/tcp/0".parse().unwrap(),
+						],
+						..Default::default()
+					})
+					.build(),
+			)
+			.unwrap(),
+			handle1,
+			handle2,
+		)
+	};
+
+	// `litep2p2` supports only the new protocol
+	let (config2, handle2) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/2"))
+		.with_max_size(1024)
+		.build();
+
+	let mut litep2p2 = Litep2p::new(
+		Litep2pConfigBuilder::new()
+			.with_request_response_protocol(config2)
+			.with_tcp(TcpConfig {
+				listen_addresses: vec![
+					"/ip4/0.0.0.0/tcp/0".parse().unwrap(),
+					"/ip6/::/tcp/0".parse().unwrap(),
+				],
+				..Default::default()
+			})
+			.build(),
+	)
+	.unwrap();
+
+	let peer1 = *litep2p1.local_peer_id();
+	let peer2 = *litep2p2.local_peer_id();
+
+	connect_peers(&mut litep2p1, &mut litep2p2).await;
+
+	let (outbound_tx1, outbound_rx1) = tracing_unbounded("outbound-request", 1000);
+	let (outbound_tx_fallback, outbound_rx_fallback) = tracing_unbounded("outbound-request", 1000);
+
+	let senders1 = HashMap::from_iter([
+		(ProtocolName::from("/protocol/2"), outbound_tx1.clone()),
+		(ProtocolName::from("/protocol/1"), outbound_tx_fallback),
+	]);
+
+	let (tx1, _rx1) = async_channel::bounded(4);
+	let protocol1 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/2"),
+		handle1_1,
+		Arc::new(peerstore_handle_test()),
+		Some(tx1),
+		outbound_rx1,
+		senders1.clone(),
+		None,
+	);
+
+	let (tx_fallback, _rx_fallback) = async_channel::bounded(4);
+	let protocol_fallback = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle1_2,
+		Arc::new(peerstore_handle_test()),
+		Some(tx_fallback),
+		outbound_rx_fallback,
+		senders1,
+		None,
+	);
+
+	let (outbound_tx2, outbound_rx2) = tracing_unbounded("outbound-request", 1000);
+	let senders2 = HashMap::from_iter([(ProtocolName::from("/protocol/2"), outbound_tx2)]);
+
+	let (tx2, rx2) = async_channel::bounded(4);
+	let protocol2 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/2"),
+		handle2,
+		Arc::new(peerstore_handle_test()),
+		Some(tx2),
+		outbound_rx2,
+		senders2,
+		None,
+	);
+
+	tokio::spawn(protocol1.run());
+	tokio::spawn(protocol2.run());
+	tokio::spawn(protocol_fallback.run());
+	tokio::spawn(async move { while let Some(_) = litep2p1.next_event().await {} });
+	tokio::spawn(async move { while let Some(_) = litep2p2.next_event().await {} });
+
+	let (result_tx, result_rx) = oneshot::channel();
+	outbound_tx1
+		.unbounded_send(OutboundRequest {
+			peer: peer2.into(),
+			request: vec![1, 2, 3, 4],
+			sender: result_tx,
+			fallback_request: Some((vec![1, 3, 3, 7], ProtocolName::from("/protocol/1"))),
+			dial_behavior: IfDisconnected::ImmediateError,
+		})
+		.unwrap();
+
+	match rx2.recv().await {
+		Ok(IncomingRequest { peer, payload, pending_response }) => {
+			assert_eq!(peer, peer1.into());
+			assert_eq!(payload, vec![1, 2, 3, 4]);
+			pending_response
+				.send(OutgoingResponse {
+					result: Ok(vec![5, 6, 7, 8]),
+					reputation_changes: Vec::new(),
+					sent_feedback: None,
+				})
+				.unwrap();
+		},
+		event => panic!("invalid event: {event:?}"),
+	}
+
+	match result_rx.await {
+		Ok(Ok((response, protocol))) => {
+			assert_eq!(response, vec![5, 6, 7, 8]);
+			assert_eq!(protocol, ProtocolName::from("/protocol/2"));
+		},
+		event => panic!("invalid event: {event:?}"),
+	}
+}
+
+#[tokio::test]
+async fn fallback_request_old_peer_receives() {
+	pezsp_tracing::try_init_simple();
+
+	// `litep2p1` supports both the new and the old protocol
+	let (mut litep2p1, handle1_1, handle1_2) = {
+		let (config1, handle1) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/2"))
+			.with_max_size(1024)
+			.build();
+
+		let (config2, handle2) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/1"))
+			.with_max_size(1024)
+			.build();
+		(
+			Litep2p::new(
+				Litep2pConfigBuilder::new()
+					.with_request_response_protocol(config1)
+					.with_request_response_protocol(config2)
+					.with_tcp(TcpConfig {
+						listen_addresses: vec![
+							"/ip4/0.0.0.0/tcp/0".parse().unwrap(),
+							"/ip6/::/tcp/0".parse().unwrap(),
+						],
+						..Default::default()
+					})
+					.build(),
+			)
+			.unwrap(),
+			handle1,
+			handle2,
+		)
+	};
+
+	// `litep2p2` supports only the new protocol
+	let (config2, handle2) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/1"))
+		.with_max_size(1024)
+		.build();
+
+	let mut litep2p2 = Litep2p::new(
+		Litep2pConfigBuilder::new()
+			.with_request_response_protocol(config2)
+			.with_tcp(TcpConfig {
+				listen_addresses: vec![
+					"/ip4/0.0.0.0/tcp/0".parse().unwrap(),
+					"/ip6/::/tcp/0".parse().unwrap(),
+				],
+				..Default::default()
+			})
+			.build(),
+	)
+	.unwrap();
+
+	let peer1 = *litep2p1.local_peer_id();
+	let peer2 = *litep2p2.local_peer_id();
+
+	connect_peers(&mut litep2p1, &mut litep2p2).await;
+
+	let (outbound_tx1, outbound_rx1) = tracing_unbounded("outbound-request", 1000);
+	let (outbound_tx_fallback, outbound_rx_fallback) = tracing_unbounded("outbound-request", 1000);
+
+	let senders1 = HashMap::from_iter([
+		(ProtocolName::from("/protocol/2"), outbound_tx1.clone()),
+		(ProtocolName::from("/protocol/1"), outbound_tx_fallback),
+	]);
+
+	let (tx1, _rx1) = async_channel::bounded(4);
+	let protocol1 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/2"),
+		handle1_1,
+		Arc::new(peerstore_handle_test()),
+		Some(tx1),
+		outbound_rx1,
+		senders1.clone(),
+		None,
+	);
+
+	let (tx_fallback, _rx_fallback) = async_channel::bounded(4);
+	let protocol_fallback = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle1_2,
+		Arc::new(peerstore_handle_test()),
+		Some(tx_fallback),
+		outbound_rx_fallback,
+		senders1,
+		None,
+	);
+
+	let (outbound_tx2, outbound_rx2) = tracing_unbounded("outbound-request", 1000);
+	let senders2 = HashMap::from_iter([(ProtocolName::from("/protocol/1"), outbound_tx2)]);
+
+	let (tx2, rx2) = async_channel::bounded(4);
+	let protocol2 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle2,
+		Arc::new(peerstore_handle_test()),
+		Some(tx2),
+		outbound_rx2,
+		senders2,
+		None,
+	);
+
+	tokio::spawn(protocol1.run());
+	tokio::spawn(protocol2.run());
+	tokio::spawn(protocol_fallback.run());
+	tokio::spawn(async move { while let Some(_) = litep2p1.next_event().await {} });
+	tokio::spawn(async move { while let Some(_) = litep2p2.next_event().await {} });
+
+	let (result_tx, result_rx) = oneshot::channel();
+	outbound_tx1
+		.unbounded_send(OutboundRequest {
+			peer: peer2.into(),
+			request: vec![1, 2, 3, 4],
+			sender: result_tx,
+			fallback_request: Some((vec![1, 3, 3, 7], ProtocolName::from("/protocol/1"))),
+			dial_behavior: IfDisconnected::ImmediateError,
+		})
+		.unwrap();
+
+	match rx2.recv().await {
+		Ok(IncomingRequest { peer, payload, pending_response }) => {
+			assert_eq!(peer, peer1.into());
+			assert_eq!(payload, vec![1, 3, 3, 7]);
+			pending_response
+				.send(OutgoingResponse {
+					result: Ok(vec![1, 3, 3, 8]),
+					reputation_changes: Vec::new(),
+					sent_feedback: None,
+				})
+				.unwrap();
+		},
+		event => panic!("invalid event: {event:?}"),
+	}
+
+	match result_rx.await {
+		Ok(Ok((response, protocol))) => {
+			assert_eq!(response, vec![1, 3, 3, 8]);
+			assert_eq!(protocol, ProtocolName::from("/protocol/1"));
+		},
+		event => panic!("invalid event: {event:?}"),
+	}
+}
+
+#[tokio::test]
+async fn fallback_request_old_peer_sends() {
+	pezsp_tracing::try_init_simple();
+
+	// `litep2p1` supports both the new and the old protocol
+	let (mut litep2p1, handle1_1, handle1_2) = {
+		let (config1, handle1) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/2"))
+			.with_max_size(1024)
+			.build();
+
+		let (config2, handle2) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/1"))
+			.with_max_size(1024)
+			.build();
+		(
+			Litep2p::new(
+				Litep2pConfigBuilder::new()
+					.with_request_response_protocol(config1)
+					.with_request_response_protocol(config2)
+					.with_tcp(TcpConfig {
+						listen_addresses: vec![
+							"/ip4/0.0.0.0/tcp/0".parse().unwrap(),
+							"/ip6/::/tcp/0".parse().unwrap(),
+						],
+						..Default::default()
+					})
+					.build(),
+			)
+			.unwrap(),
+			handle1,
+			handle2,
+		)
+	};
+
+	// `litep2p2` supports only the new protocol
+	let (config2, handle2) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/1"))
+		.with_max_size(1024)
+		.build();
+
+	let mut litep2p2 = Litep2p::new(
+		Litep2pConfigBuilder::new()
+			.with_request_response_protocol(config2)
+			.with_tcp(TcpConfig {
+				listen_addresses: vec![
+					"/ip4/0.0.0.0/tcp/0".parse().unwrap(),
+					"/ip6/::/tcp/0".parse().unwrap(),
+				],
+				..Default::default()
+			})
+			.build(),
+	)
+	.unwrap();
+
+	let peer1 = *litep2p1.local_peer_id();
+	let peer2 = *litep2p2.local_peer_id();
+
+	connect_peers(&mut litep2p1, &mut litep2p2).await;
+
+	let (outbound_tx1, outbound_rx1) = tracing_unbounded("outbound-request", 1000);
+	let (outbound_tx_fallback, outbound_rx_fallback) = tracing_unbounded("outbound-request", 1000);
+
+	let senders1 = HashMap::from_iter([
+		(ProtocolName::from("/protocol/2"), outbound_tx1.clone()),
+		(ProtocolName::from("/protocol/1"), outbound_tx_fallback),
+	]);
+
+	let (tx1, _rx1) = async_channel::bounded(4);
+	let protocol1 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/2"),
+		handle1_1,
+		Arc::new(peerstore_handle_test()),
+		Some(tx1),
+		outbound_rx1,
+		senders1.clone(),
+		None,
+	);
+
+	let (tx_fallback, rx_fallback) = async_channel::bounded(4);
+	let protocol_fallback = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle1_2,
+		Arc::new(peerstore_handle_test()),
+		Some(tx_fallback),
+		outbound_rx_fallback,
+		senders1,
+		None,
+	);
+
+	let (outbound_tx2, outbound_rx2) = tracing_unbounded("outbound-request", 1000);
+	let senders2 = HashMap::from_iter([(ProtocolName::from("/protocol/1"), outbound_tx2.clone())]);
+
+	let (tx2, _rx2) = async_channel::bounded(4);
+	let protocol2 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle2,
+		Arc::new(peerstore_handle_test()),
+		Some(tx2),
+		outbound_rx2,
+		senders2,
+		None,
+	);
+
+	tokio::spawn(protocol1.run());
+	tokio::spawn(protocol2.run());
+	tokio::spawn(protocol_fallback.run());
+	tokio::spawn(async move { while let Some(_) = litep2p1.next_event().await {} });
+	tokio::spawn(async move { while let Some(_) = litep2p2.next_event().await {} });
+
+	let (result_tx, result_rx) = oneshot::channel();
+	outbound_tx2
+		.unbounded_send(OutboundRequest {
+			peer: peer1.into(),
+			request: vec![1, 2, 3, 4],
+			sender: result_tx,
+			fallback_request: None,
+			dial_behavior: IfDisconnected::ImmediateError,
+		})
+		.unwrap();
+
+	match rx_fallback.recv().await {
+		Ok(IncomingRequest { peer, payload, pending_response }) => {
+			assert_eq!(peer, peer2.into());
+			assert_eq!(payload, vec![1, 2, 3, 4]);
+			pending_response
+				.send(OutgoingResponse {
+					result: Ok(vec![1, 3, 3, 8]),
+					reputation_changes: Vec::new(),
+					sent_feedback: None,
+				})
+				.unwrap();
+		},
+		event => panic!("invalid event: {event:?}"),
+	}
+
+	match result_rx.await {
+		Ok(Ok((response, protocol))) => {
+			assert_eq!(response, vec![1, 3, 3, 8]);
+			assert_eq!(protocol, ProtocolName::from("/protocol/1"));
+		},
+		event => panic!("invalid event: {event:?}"),
+	}
+}
+
+#[tokio::test]
+async fn old_protocol_supported_but_no_fallback_provided() {
+	pezsp_tracing::try_init_simple();
+
+	// `litep2p1` supports both the new and the old protocol
+	let (mut litep2p1, handle1_1, handle1_2) = {
+		let (config1, handle1) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/2"))
+			.with_max_size(1024)
+			.build();
+
+		let (config2, handle2) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/1"))
+			.with_max_size(1024)
+			.build();
+		(
+			Litep2p::new(
+				Litep2pConfigBuilder::new()
+					.with_request_response_protocol(config1)
+					.with_request_response_protocol(config2)
+					.with_tcp(TcpConfig {
+						listen_addresses: vec![
+							"/ip4/0.0.0.0/tcp/0".parse().unwrap(),
+							"/ip6/::/tcp/0".parse().unwrap(),
+						],
+						..Default::default()
+					})
+					.build(),
+			)
+			.unwrap(),
+			handle1,
+			handle2,
+		)
+	};
+
+	// `litep2p2` supports only the old protocol
+	let (config2, handle2) = ConfigBuilder::new(litep2p::ProtocolName::from("/protocol/1"))
+		.with_max_size(1024)
+		.build();
+
+	let mut litep2p2 = Litep2p::new(
+		Litep2pConfigBuilder::new()
+			.with_request_response_protocol(config2)
+			.with_tcp(TcpConfig {
+				listen_addresses: vec![
+					"/ip4/0.0.0.0/tcp/0".parse().unwrap(),
+					"/ip6/::/tcp/0".parse().unwrap(),
+				],
+				..Default::default()
+			})
+			.build(),
+	)
+	.unwrap();
+
+	let peer2 = *litep2p2.local_peer_id();
+
+	connect_peers(&mut litep2p1, &mut litep2p2).await;
+
+	let (outbound_tx1, outbound_rx1) = tracing_unbounded("outbound-request", 1000);
+	let (outbound_tx_fallback, outbound_rx_fallback) = tracing_unbounded("outbound-request", 1000);
+
+	let senders1 = HashMap::from_iter([
+		(ProtocolName::from("/protocol/2"), outbound_tx1.clone()),
+		(ProtocolName::from("/protocol/1"), outbound_tx_fallback),
+	]);
+
+	let (tx1, _rx1) = async_channel::bounded(4);
+	let protocol1 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/2"),
+		handle1_1,
+		Arc::new(peerstore_handle_test()),
+		Some(tx1),
+		outbound_rx1,
+		senders1.clone(),
+		None,
+	);
+
+	let (tx_fallback, _rx_fallback) = async_channel::bounded(4);
+	let protocol_fallback = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle1_2,
+		Arc::new(peerstore_handle_test()),
+		Some(tx_fallback),
+		outbound_rx_fallback,
+		senders1,
+		None,
+	);
+
+	let (outbound_tx2, outbound_rx2) = tracing_unbounded("outbound-request", 1000);
+	let senders2 = HashMap::from_iter([(ProtocolName::from("/protocol/1"), outbound_tx2)]);
+
+	let (tx2, _rx2) = async_channel::bounded(4);
+	let protocol2 = RequestResponseProtocol::new(
+		ProtocolName::from("/protocol/1"),
+		handle2,
+		Arc::new(peerstore_handle_test()),
+		Some(tx2),
+		outbound_rx2,
+		senders2,
+		None,
+	);
+
+	tokio::spawn(protocol1.run());
+	tokio::spawn(protocol2.run());
+	tokio::spawn(protocol_fallback.run());
+	tokio::spawn(async move { while let Some(_) = litep2p1.next_event().await {} });
+	tokio::spawn(async move { while let Some(_) = litep2p2.next_event().await {} });
+
+	let (result_tx, result_rx) = oneshot::channel();
+	outbound_tx1
+		.unbounded_send(OutboundRequest {
+			peer: peer2.into(),
+			request: vec![1, 2, 3, 4],
+			sender: result_tx,
+			fallback_request: None,
+			dial_behavior: IfDisconnected::ImmediateError,
+		})
+		.unwrap();
+
+	match result_rx.await {
+		Ok(Err(error)) => {
+			assert!(std::matches!(error, RequestFailure::Refused));
+		},
+		event => panic!("invalid event: {event:?}"),
+	}
+}

bizinikiwi/client/network/src/mock.rs

@@ -0,0 +1,73 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Mocked components for tests.
+
+use crate::{
+	peer_store::{PeerStoreProvider, ProtocolHandle},
+	ReputationChange,
+};
+
+use pezsc_network_common::role::ObservedRole;
+use pezsc_network_types::PeerId;
+
+use std::{collections::HashSet, sync::Arc};
+
+/// No-op `PeerStore`.
+#[derive(Debug)]
+pub struct MockPeerStore {}
+
+impl PeerStoreProvider for MockPeerStore {
+	fn is_banned(&self, _peer_id: &PeerId) -> bool {
+		// Make sure that the peer is not banned.
+		false
+	}
+
+	fn register_protocol(&self, _protocol_handle: Arc<dyn ProtocolHandle>) {
+		// Make sure not to fail.
+	}
+
+	fn report_disconnect(&self, _peer_id: PeerId) {
+		// Make sure not to fail.
+	}
+
+	fn report_peer(&self, _peer_id: PeerId, _change: ReputationChange) {
+		// Make sure not to fail.
+	}
+
+	fn peer_reputation(&self, _peer_id: &PeerId) -> i32 {
+		// Make sure that the peer is not banned.
+		0
+	}
+
+	fn peer_role(&self, _peer_id: &PeerId) -> Option<ObservedRole> {
+		None
+	}
+
+	fn set_peer_role(&self, _peer_id: &PeerId, _role: ObservedRole) {
+		unimplemented!();
+	}
+
+	fn outgoing_candidates(&self, _count: usize, _ignored: HashSet<PeerId>) -> Vec<PeerId> {
+		unimplemented!()
+	}
+
+	fn add_known_peer(&self, _peer_id: PeerId) {
+		unimplemented!()
+	}
+}

bizinikiwi/client/network/src/network_state.rs

@@ -0,0 +1,124 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Information about the networking, for diagnostic purposes.
+//!
+//! **Warning**: These APIs are not stable.
+
+use libp2p::{
+	core::{ConnectedPoint, Endpoint as CoreEndpoint},
+	Multiaddr,
+};
+use serde::{Deserialize, Serialize};
+use std::{
+	collections::{HashMap, HashSet},
+	time::Duration,
+};
+
+/// Returns general information about the networking.
+///
+/// Meant for general diagnostic purposes.
+///
+/// **Warning**: This API is not stable.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct NetworkState {
+	/// PeerId of the local node.
+	pub peer_id: String,
+	/// List of addresses the node is currently listening on.
+	pub listened_addresses: HashSet<Multiaddr>,
+	/// List of addresses the node knows it can be reached as.
+	pub external_addresses: HashSet<Multiaddr>,
+	/// List of node we're connected to.
+	pub connected_peers: HashMap<String, Peer>,
+	/// List of node that we know of but that we're not connected to.
+	pub not_connected_peers: HashMap<String, NotConnectedPeer>,
+	/// State of the peerset manager.
+	pub peerset: serde_json::Value,
+}
+
+/// Part of the `NetworkState` struct. Unstable.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Peer {
+	/// How we are connected to the node.
+	pub endpoint: PeerEndpoint,
+	/// Node information, as provided by the node itself. Can be empty if not known yet.
+	pub version_string: Option<String>,
+	/// Latest ping duration with this node.
+	pub latest_ping_time: Option<Duration>,
+	/// List of addresses known for this node.
+	pub known_addresses: HashSet<Multiaddr>,
+}
+
+/// Part of the `NetworkState` struct. Unstable.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct NotConnectedPeer {
+	/// List of addresses known for this node.
+	pub known_addresses: HashSet<Multiaddr>,
+	/// Node information, as provided by the node itself, if we were ever connected to this node.
+	pub version_string: Option<String>,
+	/// Latest ping duration with this node, if we were ever connected to this node.
+	pub latest_ping_time: Option<Duration>,
+}
+
+/// Part of the `NetworkState` struct. Unstable.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum PeerEndpoint {
+	/// We are dialing the given address.
+	Dialing(Multiaddr, Endpoint),
+	/// We are listening.
+	Listening {
+		/// Local address of the connection.
+		local_addr: Multiaddr,
+		/// Address data is sent back to.
+		send_back_addr: Multiaddr,
+	},
+}
+
+/// Part of the `NetworkState` struct. Unstable.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum Endpoint {
+	/// The socket comes from a dialer.
+	Dialer,
+	/// The socket comes from a listener.
+	Listener,
+}
+
+impl From<ConnectedPoint> for PeerEndpoint {
+	fn from(endpoint: ConnectedPoint) -> Self {
+		match endpoint {
+			ConnectedPoint::Dialer { address, role_override, port_use: _ } =>
+				Self::Dialing(address, role_override.into()),
+			ConnectedPoint::Listener { local_addr, send_back_addr } =>
+				Self::Listening { local_addr, send_back_addr },
+		}
+	}
+}
+
+impl From<CoreEndpoint> for Endpoint {
+	fn from(endpoint: CoreEndpoint) -> Self {
+		match endpoint {
+			CoreEndpoint::Dialer => Self::Dialer,
+			CoreEndpoint::Listener => Self::Listener,
+		}
+	}
+}

bizinikiwi/client/network/src/peer_info.rs

@@ -0,0 +1,664 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! [`PeerInfoBehaviour`] is implementation of `NetworkBehaviour` that holds information about peers
+//! in cache.
+
+use crate::{utils::interval, LOG_TARGET};
+use either::Either;
+
+use fnv::FnvHashMap;
+use futures::prelude::*;
+use libp2p::{
+	core::{transport::PortUse, ConnectedPoint, Endpoint},
+	identify::{
+		Behaviour as Identify, Config as IdentifyConfig, Event as IdentifyEvent,
+		Info as IdentifyInfo,
+	},
+	identity::PublicKey,
+	multiaddr::Protocol,
+	ping::{Behaviour as Ping, Config as PingConfig, Event as PingEvent},
+	swarm::{
+		behaviour::{
+			AddressChange, ConnectionClosed, ConnectionEstablished, DialFailure, FromSwarm,
+			ListenFailure,
+		},
+		ConnectionDenied, ConnectionHandler, ConnectionHandlerSelect, ConnectionId,
+		NetworkBehaviour, THandler, THandlerInEvent, THandlerOutEvent, ToSwarm,
+	},
+	Multiaddr, PeerId,
+};
+use log::{debug, error, trace, warn};
+use parking_lot::Mutex;
+use schnellru::{ByLength, LruMap};
+use smallvec::SmallVec;
+
+use std::{
+	collections::{hash_map::Entry, HashSet, VecDeque},
+	iter,
+	pin::Pin,
+	sync::Arc,
+	task::{Context, Poll},
+	time::{Duration, Instant},
+};
+
+/// Time after we disconnect from a node before we purge its information from the cache.
+const CACHE_EXPIRE: Duration = Duration::from_secs(10 * 60);
+/// Interval at which we perform garbage collection on the node info.
+const GARBAGE_COLLECT_INTERVAL: Duration = Duration::from_secs(2 * 60);
+/// The maximum number of tracked external addresses we allow.
+const MAX_EXTERNAL_ADDRESSES: u32 = 32;
+/// Number of times observed address is received from different peers before it is confirmed as
+/// external.
+const MIN_ADDRESS_CONFIRMATIONS: usize = 3;
+
+/// Implementation of `NetworkBehaviour` that holds information about peers in cache.
+pub struct PeerInfoBehaviour {
+	/// Periodically ping nodes, and close the connection if it's unresponsive.
+	ping: Ping,
+	/// Periodically identifies the remote and responds to incoming requests.
+	identify: Identify,
+	/// Information that we know about all nodes.
+	nodes_info: FnvHashMap<PeerId, NodeInfo>,
+	/// Interval at which we perform garbage collection in `nodes_info`.
+	garbage_collect: Pin<Box<dyn Stream<Item = ()> + Send>>,
+	/// PeerId of the local node.
+	local_peer_id: PeerId,
+	/// Public addresses supplied by the operator. Never expire.
+	public_addresses: Vec<Multiaddr>,
+	/// Listen addresses. External addresses matching listen addresses never expire.
+	listen_addresses: HashSet<Multiaddr>,
+	/// External address confirmations.
+	address_confirmations: LruMap<Multiaddr, HashSet<PeerId>>,
+	/// Record keeping of external addresses. Data is queried by the `NetworkService`.
+	/// The addresses contain the `/p2p/...` part with local peer ID.
+	external_addresses: ExternalAddresses,
+	/// Pending events to emit to [`Swarm`](libp2p::swarm::Swarm).
+	pending_actions: VecDeque<ToSwarm<PeerInfoEvent, THandlerInEvent<PeerInfoBehaviour>>>,
+}
+
+/// Information about a node we're connected to.
+#[derive(Debug)]
+struct NodeInfo {
+	/// When we will remove the entry about this node from the list, or `None` if we're connected
+	/// to the node.
+	info_expire: Option<Instant>,
+	/// Non-empty list of connected endpoints, one per connection.
+	endpoints: SmallVec<[ConnectedPoint; crate::MAX_CONNECTIONS_PER_PEER]>,
+	/// Version reported by the remote, or `None` if unknown.
+	client_version: Option<String>,
+	/// Latest ping time with this node.
+	latest_ping: Option<Duration>,
+}
+
+impl NodeInfo {
+	fn new(endpoint: ConnectedPoint) -> Self {
+		let mut endpoints = SmallVec::new();
+		endpoints.push(endpoint);
+		Self { info_expire: None, endpoints, client_version: None, latest_ping: None }
+	}
+}
+
+/// Utility struct for tracking external addresses. The data is shared with the `NetworkService`.
+#[derive(Debug, Clone, Default)]
+pub struct ExternalAddresses {
+	addresses: Arc<Mutex<HashSet<Multiaddr>>>,
+}
+
+impl ExternalAddresses {
+	/// Add an external address.
+	pub fn add(&mut self, addr: Multiaddr) -> bool {
+		self.addresses.lock().insert(addr)
+	}
+
+	/// Remove an external address.
+	pub fn remove(&mut self, addr: &Multiaddr) -> bool {
+		self.addresses.lock().remove(addr)
+	}
+}
+
+impl PeerInfoBehaviour {
+	/// Builds a new `PeerInfoBehaviour`.
+	pub fn new(
+		user_agent: String,
+		local_public_key: PublicKey,
+		external_addresses: Arc<Mutex<HashSet<Multiaddr>>>,
+		public_addresses: Vec<Multiaddr>,
+	) -> Self {
+		let identify = {
+			let cfg = IdentifyConfig::new("/bizinikiwi/1.0".to_string(), local_public_key.clone())
+				.with_agent_version(user_agent)
+				// We don't need any peer information cached.
+				.with_cache_size(0);
+			Identify::new(cfg)
+		};
+
+		Self {
+			ping: Ping::new(PingConfig::new()),
+			identify,
+			nodes_info: FnvHashMap::default(),
+			garbage_collect: Box::pin(interval(GARBAGE_COLLECT_INTERVAL)),
+			local_peer_id: local_public_key.to_peer_id(),
+			public_addresses,
+			listen_addresses: HashSet::new(),
+			address_confirmations: LruMap::new(ByLength::new(MAX_EXTERNAL_ADDRESSES)),
+			external_addresses: ExternalAddresses { addresses: external_addresses },
+			pending_actions: Default::default(),
+		}
+	}
+
+	/// Borrows `self` and returns a struct giving access to the information about a node.
+	///
+	/// Returns `None` if we don't know anything about this node. Always returns `Some` for nodes
+	/// we're connected to, meaning that if `None` is returned then we're not connected to that
+	/// node.
+	pub fn node(&self, peer_id: &PeerId) -> Option<Node<'_>> {
+		self.nodes_info.get(peer_id).map(Node)
+	}
+
+	/// Inserts a ping time in the cache. Has no effect if we don't have any entry for that node,
+	/// which shouldn't happen.
+	fn handle_ping_report(
+		&mut self,
+		peer_id: &PeerId,
+		ping_time: Duration,
+		connection: ConnectionId,
+	) {
+		trace!(target: LOG_TARGET, "Ping time with {:?} via {:?}: {:?}", peer_id, connection, ping_time);
+		if let Some(entry) = self.nodes_info.get_mut(peer_id) {
+			entry.latest_ping = Some(ping_time);
+		} else {
+			error!(target: LOG_TARGET,
+				"Received ping from node we're not connected to {:?} via {:?}", peer_id, connection);
+		}
+	}
+
+	/// Ensure address has the `/p2p/...` part with local peer id. Returns `Err` if the address
+	/// already contains a different peer id.
+	fn with_local_peer_id(&self, address: Multiaddr) -> Result<Multiaddr, Multiaddr> {
+		if let Some(Protocol::P2p(peer_id)) = address.iter().last() {
+			if peer_id == self.local_peer_id {
+				Ok(address)
+			} else {
+				Err(address)
+			}
+		} else {
+			Ok(address.with(Protocol::P2p(self.local_peer_id)))
+		}
+	}
+
+	/// Inserts an identify record in the cache & discovers external addresses when multiple
+	/// peers report the same address as observed.
+	fn handle_identify_report(&mut self, peer_id: &PeerId, info: &IdentifyInfo) {
+		trace!(target: LOG_TARGET, "Identified {:?} => {:?}", peer_id, info);
+		if let Some(entry) = self.nodes_info.get_mut(peer_id) {
+			entry.client_version = Some(info.agent_version.clone());
+		} else {
+			error!(target: LOG_TARGET,
+				"Received identify message from node we're not connected to {peer_id:?}");
+		}
+		// Discover external addresses.
+		match self.with_local_peer_id(info.observed_addr.clone()) {
+			Ok(observed_addr) => {
+				let (is_new, expired) = self.is_new_external_address(&observed_addr, *peer_id);
+				if is_new && self.external_addresses.add(observed_addr.clone()) {
+					trace!(
+						target: LOG_TARGET,
+						"Observed address reported by Identify confirmed as external {}",
+						observed_addr,
+					);
+					self.pending_actions.push_back(ToSwarm::ExternalAddrConfirmed(observed_addr));
+				}
+				if let Some(expired) = expired {
+					trace!(target: LOG_TARGET, "Removing replaced external address: {expired}");
+					self.external_addresses.remove(&expired);
+					self.pending_actions.push_back(ToSwarm::ExternalAddrExpired(expired));
+				}
+			},
+			Err(addr) => {
+				warn!(
+					target: LOG_TARGET,
+					"Identify reported observed address for a peer that is not us: {addr}",
+				);
+			},
+		}
+	}
+
+	/// Check if addresses are equal taking into account they can contain or not contain
+	/// the `/p2p/...` part.
+	fn is_same_address(left: &Multiaddr, right: &Multiaddr) -> bool {
+		let mut left = left.iter();
+		let mut right = right.iter();
+
+		loop {
+			match (left.next(), right.next()) {
+				(None, None) => return true,
+				(None, Some(Protocol::P2p(_))) => return true,
+				(Some(Protocol::P2p(_)), None) => return true,
+				(left, right) if left != right => return false,
+				_ => {},
+			}
+		}
+	}
+
+	/// Check if `address` can be considered a new external address.
+	///
+	/// If this address replaces an older address, the expired address is returned.
+	fn is_new_external_address(
+		&mut self,
+		address: &Multiaddr,
+		peer_id: PeerId,
+	) -> (bool, Option<Multiaddr>) {
+		trace!(target: LOG_TARGET, "Verify new external address: {address}");
+
+		// Public and listen addresses don't count towards discovered external addresses
+		// and are always confirmed.
+		// Because they are not kept in the LRU, they are never replaced by discovered
+		// external addresses.
+		if self
+			.listen_addresses
+			.iter()
+			.chain(self.public_addresses.iter())
+			.any(|known_address| PeerInfoBehaviour::is_same_address(&known_address, &address))
+		{
+			return (true, None);
+		}
+
+		match self.address_confirmations.get(address) {
+			Some(confirmations) => {
+				confirmations.insert(peer_id);
+
+				if confirmations.len() >= MIN_ADDRESS_CONFIRMATIONS {
+					return (true, None);
+				}
+			},
+			None => {
+				let oldest = (self.address_confirmations.len() >=
+					self.address_confirmations.limiter().max_length() as usize)
+					.then(|| {
+						self.address_confirmations.pop_oldest().map(|(address, peers)| {
+							if peers.len() >= MIN_ADDRESS_CONFIRMATIONS {
+								return Some(address);
+							} else {
+								None
+							}
+						})
+					})
+					.flatten()
+					.flatten();
+
+				self.address_confirmations
+					.insert(address.clone(), iter::once(peer_id).collect());
+
+				return (false, oldest);
+			},
+		}
+
+		(false, None)
+	}
+}
+
+/// Gives access to the information about a node.
+pub struct Node<'a>(&'a NodeInfo);
+
+impl<'a> Node<'a> {
+	/// Returns the endpoint of an established connection to the peer.
+	///
+	/// Returns `None` if we are disconnected from the node.
+	pub fn endpoint(&self) -> Option<&'a ConnectedPoint> {
+		self.0.endpoints.get(0)
+	}
+
+	/// Returns the latest version information we know of.
+	pub fn client_version(&self) -> Option<&'a str> {
+		self.0.client_version.as_deref()
+	}
+
+	/// Returns the latest ping time we know of for this node. `None` if we never successfully
+	/// pinged this node.
+	pub fn latest_ping(&self) -> Option<Duration> {
+		self.0.latest_ping
+	}
+}
+
+/// Event that can be emitted by the behaviour.
+#[derive(Debug)]
+pub enum PeerInfoEvent {
+	/// We have obtained identity information from a peer, including the addresses it is listening
+	/// on.
+	Identified {
+		/// Id of the peer that has been identified.
+		peer_id: PeerId,
+		/// Information about the peer.
+		info: IdentifyInfo,
+	},
+}
+
+impl NetworkBehaviour for PeerInfoBehaviour {
+	type ConnectionHandler = ConnectionHandlerSelect<
+		<Ping as NetworkBehaviour>::ConnectionHandler,
+		<Identify as NetworkBehaviour>::ConnectionHandler,
+	>;
+	type ToSwarm = PeerInfoEvent;
+
+	fn handle_pending_inbound_connection(
+		&mut self,
+		connection_id: ConnectionId,
+		local_addr: &Multiaddr,
+		remote_addr: &Multiaddr,
+	) -> Result<(), ConnectionDenied> {
+		self.ping
+			.handle_pending_inbound_connection(connection_id, local_addr, remote_addr)?;
+		self.identify
+			.handle_pending_inbound_connection(connection_id, local_addr, remote_addr)
+	}
+
+	fn handle_pending_outbound_connection(
+		&mut self,
+		_connection_id: ConnectionId,
+		_maybe_peer: Option<PeerId>,
+		_addresses: &[Multiaddr],
+		_effective_role: Endpoint,
+	) -> Result<Vec<Multiaddr>, ConnectionDenied> {
+		// Only `Discovery::handle_pending_outbound_connection` must be returning addresses to
+		// ensure that we don't return unwanted addresses.
+		Ok(Vec::new())
+	}
+
+	fn handle_established_inbound_connection(
+		&mut self,
+		connection_id: ConnectionId,
+		peer: PeerId,
+		local_addr: &Multiaddr,
+		remote_addr: &Multiaddr,
+	) -> Result<THandler<Self>, ConnectionDenied> {
+		let ping_handler = self.ping.handle_established_inbound_connection(
+			connection_id,
+			peer,
+			local_addr,
+			remote_addr,
+		)?;
+		let identify_handler = self.identify.handle_established_inbound_connection(
+			connection_id,
+			peer,
+			local_addr,
+			remote_addr,
+		)?;
+		Ok(ping_handler.select(identify_handler))
+	}
+
+	fn handle_established_outbound_connection(
+		&mut self,
+		connection_id: ConnectionId,
+		peer: PeerId,
+		addr: &Multiaddr,
+		role_override: Endpoint,
+		port_use: PortUse,
+	) -> Result<THandler<Self>, ConnectionDenied> {
+		let ping_handler = self.ping.handle_established_outbound_connection(
+			connection_id,
+			peer,
+			addr,
+			role_override,
+			port_use,
+		)?;
+		let identify_handler = self.identify.handle_established_outbound_connection(
+			connection_id,
+			peer,
+			addr,
+			role_override,
+			port_use,
+		)?;
+		Ok(ping_handler.select(identify_handler))
+	}
+
+	fn on_swarm_event(&mut self, event: FromSwarm) {
+		match event {
+			FromSwarm::ConnectionEstablished(
+				e @ ConnectionEstablished { peer_id, endpoint, .. },
+			) => {
+				self.ping.on_swarm_event(FromSwarm::ConnectionEstablished(e));
+				self.identify.on_swarm_event(FromSwarm::ConnectionEstablished(e));
+
+				match self.nodes_info.entry(peer_id) {
+					Entry::Vacant(e) => {
+						e.insert(NodeInfo::new(endpoint.clone()));
+					},
+					Entry::Occupied(e) => {
+						let e = e.into_mut();
+						if e.info_expire.as_ref().map(|exp| *exp < Instant::now()).unwrap_or(false)
+						{
+							e.client_version = None;
+							e.latest_ping = None;
+						}
+						e.info_expire = None;
+						e.endpoints.push(endpoint.clone());
+					},
+				}
+			},
+			FromSwarm::ConnectionClosed(ConnectionClosed {
+				peer_id,
+				connection_id,
+				endpoint,
+				cause,
+				remaining_established,
+			}) => {
+				self.ping.on_swarm_event(FromSwarm::ConnectionClosed(ConnectionClosed {
+					peer_id,
+					connection_id,
+					endpoint,
+					cause,
+					remaining_established,
+				}));
+				self.identify.on_swarm_event(FromSwarm::ConnectionClosed(ConnectionClosed {
+					peer_id,
+					connection_id,
+					endpoint,
+					cause,
+					remaining_established,
+				}));
+
+				if let Some(entry) = self.nodes_info.get_mut(&peer_id) {
+					if remaining_established == 0 {
+						entry.info_expire = Some(Instant::now() + CACHE_EXPIRE);
+					}
+					entry.endpoints.retain(|ep| ep != endpoint)
+				} else {
+					error!(target: LOG_TARGET,
+						"Unknown connection to {:?} closed: {:?}", peer_id, endpoint);
+				}
+			},
+			FromSwarm::DialFailure(DialFailure { peer_id, error, connection_id }) => {
+				self.ping.on_swarm_event(FromSwarm::DialFailure(DialFailure {
+					peer_id,
+					error,
+					connection_id,
+				}));
+				self.identify.on_swarm_event(FromSwarm::DialFailure(DialFailure {
+					peer_id,
+					error,
+					connection_id,
+				}));
+			},
+			FromSwarm::ListenerClosed(e) => {
+				self.ping.on_swarm_event(FromSwarm::ListenerClosed(e));
+				self.identify.on_swarm_event(FromSwarm::ListenerClosed(e));
+			},
+			FromSwarm::ListenFailure(ListenFailure {
+				local_addr,
+				send_back_addr,
+				error,
+				connection_id,
+				peer_id,
+			}) => {
+				self.ping.on_swarm_event(FromSwarm::ListenFailure(ListenFailure {
+					local_addr,
+					send_back_addr,
+					error,
+					connection_id,
+					peer_id,
+				}));
+				self.identify.on_swarm_event(FromSwarm::ListenFailure(ListenFailure {
+					local_addr,
+					send_back_addr,
+					error,
+					connection_id,
+					peer_id,
+				}));
+			},
+			FromSwarm::ListenerError(e) => {
+				self.ping.on_swarm_event(FromSwarm::ListenerError(e));
+				self.identify.on_swarm_event(FromSwarm::ListenerError(e));
+			},
+			FromSwarm::ExternalAddrExpired(e) => {
+				self.ping.on_swarm_event(FromSwarm::ExternalAddrExpired(e));
+				self.identify.on_swarm_event(FromSwarm::ExternalAddrExpired(e));
+			},
+			FromSwarm::NewListener(e) => {
+				self.ping.on_swarm_event(FromSwarm::NewListener(e));
+				self.identify.on_swarm_event(FromSwarm::NewListener(e));
+			},
+			FromSwarm::NewListenAddr(e) => {
+				self.ping.on_swarm_event(FromSwarm::NewListenAddr(e));
+				self.identify.on_swarm_event(FromSwarm::NewListenAddr(e));
+				self.listen_addresses.insert(e.addr.clone());
+			},
+			FromSwarm::ExpiredListenAddr(e) => {
+				self.ping.on_swarm_event(FromSwarm::ExpiredListenAddr(e));
+				self.identify.on_swarm_event(FromSwarm::ExpiredListenAddr(e));
+				self.listen_addresses.remove(e.addr);
+				// Remove matching external address.
+				match self.with_local_peer_id(e.addr.clone()) {
+					Ok(addr) => {
+						self.external_addresses.remove(&addr);
+						self.pending_actions.push_back(ToSwarm::ExternalAddrExpired(addr));
+					},
+					Err(addr) => {
+						warn!(
+							target: LOG_TARGET,
+							"Listen address expired with peer ID that is not us: {addr}",
+						);
+					},
+				}
+			},
+			FromSwarm::NewExternalAddrCandidate(e) => {
+				self.ping.on_swarm_event(FromSwarm::NewExternalAddrCandidate(e));
+				self.identify.on_swarm_event(FromSwarm::NewExternalAddrCandidate(e));
+			},
+			FromSwarm::ExternalAddrConfirmed(e) => {
+				self.ping.on_swarm_event(FromSwarm::ExternalAddrConfirmed(e));
+				self.identify.on_swarm_event(FromSwarm::ExternalAddrConfirmed(e));
+			},
+			FromSwarm::AddressChange(e @ AddressChange { peer_id, old, new, .. }) => {
+				self.ping.on_swarm_event(FromSwarm::AddressChange(e));
+				self.identify.on_swarm_event(FromSwarm::AddressChange(e));
+
+				if let Some(entry) = self.nodes_info.get_mut(&peer_id) {
+					if let Some(endpoint) = entry.endpoints.iter_mut().find(|e| e == &old) {
+						*endpoint = new.clone();
+					} else {
+						error!(target: LOG_TARGET,
+							"Unknown address change for peer {:?} from {:?} to {:?}", peer_id, old, new);
+					}
+				} else {
+					error!(target: LOG_TARGET,
+						"Unknown peer {:?} to change address from {:?} to {:?}", peer_id, old, new);
+				}
+			},
+			FromSwarm::NewExternalAddrOfPeer(e) => {
+				self.ping.on_swarm_event(FromSwarm::NewExternalAddrOfPeer(e));
+				self.identify.on_swarm_event(FromSwarm::NewExternalAddrOfPeer(e));
+			},
+			event => {
+				debug!(target: LOG_TARGET, "New unknown `FromSwarm` libp2p event: {event:?}");
+				self.ping.on_swarm_event(event);
+				self.identify.on_swarm_event(event);
+			},
+		}
+	}
+
+	fn on_connection_handler_event(
+		&mut self,
+		peer_id: PeerId,
+		connection_id: ConnectionId,
+		event: THandlerOutEvent<Self>,
+	) {
+		match event {
+			Either::Left(event) =>
+				self.ping.on_connection_handler_event(peer_id, connection_id, event),
+			Either::Right(event) =>
+				self.identify.on_connection_handler_event(peer_id, connection_id, event),
+		}
+	}
+
+	fn poll(&mut self, cx: &mut Context) -> Poll<ToSwarm<Self::ToSwarm, THandlerInEvent<Self>>> {
+		if let Some(event) = self.pending_actions.pop_front() {
+			return Poll::Ready(event);
+		}
+
+		loop {
+			match self.ping.poll(cx) {
+				Poll::Pending => break,
+				Poll::Ready(ToSwarm::GenerateEvent(ev)) => {
+					if let PingEvent { peer, result: Ok(rtt), connection } = ev {
+						self.handle_ping_report(&peer, rtt, connection)
+					}
+				},
+				Poll::Ready(event) => {
+					return Poll::Ready(event.map_in(Either::Left).map_out(|_| {
+						unreachable!("`GenerateEvent` is handled in a branch above; qed")
+					}));
+				},
+			}
+		}
+
+		loop {
+			match self.identify.poll(cx) {
+				Poll::Pending => break,
+				Poll::Ready(ToSwarm::GenerateEvent(event)) => match event {
+					IdentifyEvent::Received { peer_id, info, .. } => {
+						self.handle_identify_report(&peer_id, &info);
+						let event = PeerInfoEvent::Identified { peer_id, info };
+						return Poll::Ready(ToSwarm::GenerateEvent(event));
+					},
+					IdentifyEvent::Error { connection_id, peer_id, error } => {
+						debug!(
+							target: LOG_TARGET,
+							"Identification with peer {peer_id:?}({connection_id}) failed => {error}"
+						);
+					},
+					IdentifyEvent::Pushed { .. } => {},
+					IdentifyEvent::Sent { .. } => {},
+				},
+				Poll::Ready(event) => {
+					return Poll::Ready(event.map_in(Either::Right).map_out(|_| {
+						unreachable!("`GenerateEvent` is handled in a branch above; qed")
+					}));
+				},
+			}
+		}
+
+		while let Poll::Ready(Some(())) = self.garbage_collect.poll_next_unpin(cx) {
+			self.nodes_info.retain(|_, node| {
+				node.info_expire.as_ref().map(|exp| *exp >= Instant::now()).unwrap_or(true)
+			});
+		}
+
+		Poll::Pending
+	}
+}

bizinikiwi/client/network/src/peer_store.rs

@@ -0,0 +1,573 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! [`PeerStore`] manages peer reputations and provides connection candidates to
+//! [`crate::protocol_controller::ProtocolController`].
+
+use crate::service::{metrics::PeerStoreMetrics, traits::PeerStore as PeerStoreT};
+
+use libp2p::PeerId;
+use log::trace;
+use parking_lot::Mutex;
+use partial_sort::PartialSort;
+use prometheus_endpoint::Registry;
+use pezsc_network_common::{role::ObservedRole, types::ReputationChange};
+use std::{
+	cmp::{Ord, Ordering, PartialOrd},
+	collections::{hash_map::Entry, HashMap, HashSet},
+	fmt::Debug,
+	sync::Arc,
+	time::{Duration, Instant},
+};
+use wasm_timer::Delay;
+
+/// Log target for this file.
+pub const LOG_TARGET: &str = "peerset";
+
+/// We don't accept nodes whose reputation is under this value.
+pub const BANNED_THRESHOLD: i32 = 71 * (i32::MIN / 100);
+/// Reputation change for a node when we get disconnected from it.
+const DISCONNECT_REPUTATION_CHANGE: i32 = -256;
+/// Relative decrement of a reputation value that is applied every second. I.e., for inverse
+/// decrement of 200 we decrease absolute value of the reputation by 1/200.
+///
+/// This corresponds to a factor of `k = 0.955`, where k = 1 - 1 / INVERSE_DECREMENT.
+///
+/// It takes ~ `ln(0.5) / ln(k)` seconds to reduce the reputation by half, or 138.63 seconds for the
+/// values above.
+///
+/// In this setup:
+/// - `i32::MAX` becomes 0 in exactly 3544 seconds, or approximately 59 minutes
+/// - `i32::MIN` becomes 0 in exactly 3544 seconds, or approximately 59 minutes
+/// - `i32::MIN` escapes the banned threshold in 69 seconds
+const INVERSE_DECREMENT: i32 = 200;
+/// Amount of time between the moment we last updated the [`PeerStore`] entry and the moment we
+/// remove it, once the reputation value reaches 0.
+const FORGET_AFTER: Duration = Duration::from_secs(3600);
+
+/// Trait describing the required functionality from a `Peerset` handle.
+pub trait ProtocolHandle: Debug + Send + Sync {
+	/// Disconnect peer.
+	fn disconnect_peer(&self, peer_id: pezsc_network_types::PeerId);
+}
+
+/// Trait providing peer reputation management and connection candidates.
+pub trait PeerStoreProvider: Debug + Send + Sync {
+	/// Check whether the peer is banned.
+	fn is_banned(&self, peer_id: &pezsc_network_types::PeerId) -> bool;
+
+	/// Register a protocol handle to disconnect peers whose reputation drops below the threshold.
+	fn register_protocol(&self, protocol_handle: Arc<dyn ProtocolHandle>);
+
+	/// Report peer disconnection for reputation adjustment.
+	fn report_disconnect(&self, peer_id: pezsc_network_types::PeerId);
+
+	/// Adjust peer reputation.
+	fn report_peer(&self, peer_id: pezsc_network_types::PeerId, change: ReputationChange);
+
+	/// Set peer role.
+	fn set_peer_role(&self, peer_id: &pezsc_network_types::PeerId, role: ObservedRole);
+
+	/// Get peer reputation.
+	fn peer_reputation(&self, peer_id: &pezsc_network_types::PeerId) -> i32;
+
+	/// Get peer role, if available.
+	fn peer_role(&self, peer_id: &pezsc_network_types::PeerId) -> Option<ObservedRole>;
+
+	/// Get candidates with highest reputations for initiating outgoing connections.
+	fn outgoing_candidates(
+		&self,
+		count: usize,
+		ignored: HashSet<pezsc_network_types::PeerId>,
+	) -> Vec<pezsc_network_types::PeerId>;
+
+	/// Add known peer.
+	fn add_known_peer(&self, peer_id: pezsc_network_types::PeerId);
+}
+
+/// Actual implementation of peer reputations and connection candidates provider.
+#[derive(Debug, Clone)]
+pub struct PeerStoreHandle {
+	inner: Arc<Mutex<PeerStoreInner>>,
+}
+
+impl PeerStoreProvider for PeerStoreHandle {
+	fn is_banned(&self, peer_id: &pezsc_network_types::PeerId) -> bool {
+		self.inner.lock().is_banned(&peer_id.into())
+	}
+
+	fn register_protocol(&self, protocol_handle: Arc<dyn ProtocolHandle>) {
+		self.inner.lock().register_protocol(protocol_handle);
+	}
+
+	fn report_disconnect(&self, peer_id: pezsc_network_types::PeerId) {
+		let mut inner = self.inner.lock();
+		inner.report_disconnect(peer_id.into())
+	}
+
+	fn report_peer(&self, peer_id: pezsc_network_types::PeerId, change: ReputationChange) {
+		let mut inner = self.inner.lock();
+		inner.report_peer(peer_id.into(), change)
+	}
+
+	fn set_peer_role(&self, peer_id: &pezsc_network_types::PeerId, role: ObservedRole) {
+		let mut inner = self.inner.lock();
+		inner.set_peer_role(&peer_id.into(), role)
+	}
+
+	fn peer_reputation(&self, peer_id: &pezsc_network_types::PeerId) -> i32 {
+		self.inner.lock().peer_reputation(&peer_id.into())
+	}
+
+	fn peer_role(&self, peer_id: &pezsc_network_types::PeerId) -> Option<ObservedRole> {
+		self.inner.lock().peer_role(&peer_id.into())
+	}
+
+	fn outgoing_candidates(
+		&self,
+		count: usize,
+		ignored: HashSet<pezsc_network_types::PeerId>,
+	) -> Vec<pezsc_network_types::PeerId> {
+		self.inner
+			.lock()
+			.outgoing_candidates(count, ignored.iter().map(|peer_id| (*peer_id).into()).collect())
+			.iter()
+			.map(|peer_id| peer_id.into())
+			.collect()
+	}
+
+	fn add_known_peer(&self, peer_id: pezsc_network_types::PeerId) {
+		self.inner.lock().add_known_peer(peer_id.into());
+	}
+}
+
+#[derive(Debug, Clone, Copy)]
+struct PeerInfo {
+	/// Reputation of the peer.
+	reputation: i32,
+
+	/// Instant when the peer was last updated.
+	last_updated: Instant,
+
+	/// Role of the peer, if known.
+	role: Option<ObservedRole>,
+}
+
+impl Default for PeerInfo {
+	fn default() -> Self {
+		Self { reputation: 0, last_updated: Instant::now(), role: None }
+	}
+}
+
+impl PartialEq for PeerInfo {
+	fn eq(&self, other: &Self) -> bool {
+		self.reputation == other.reputation
+	}
+}
+
+impl Eq for PeerInfo {}
+
+impl Ord for PeerInfo {
+	// We define reverse order by reputation values.
+	fn cmp(&self, other: &Self) -> Ordering {
+		self.reputation.cmp(&other.reputation).reverse()
+	}
+}
+
+impl PartialOrd for PeerInfo {
+	fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+		Some(self.cmp(other))
+	}
+}
+
+impl PeerInfo {
+	fn is_banned(&self) -> bool {
+		self.reputation < BANNED_THRESHOLD
+	}
+
+	fn add_reputation(&mut self, increment: i32) {
+		self.reputation = self.reputation.saturating_add(increment);
+		self.bump_last_updated();
+	}
+
+	fn decay_reputation(&mut self, seconds_passed: u64) {
+		// Note that decaying the reputation value happens "on its own",
+		// so we don't do `bump_last_updated()`.
+		for _ in 0..seconds_passed {
+			let mut diff = self.reputation / INVERSE_DECREMENT;
+			if diff == 0 && self.reputation < 0 {
+				diff = -1;
+			} else if diff == 0 && self.reputation > 0 {
+				diff = 1;
+			}
+
+			self.reputation = self.reputation.saturating_sub(diff);
+
+			if self.reputation == 0 {
+				break;
+			}
+		}
+	}
+
+	fn bump_last_updated(&mut self) {
+		self.last_updated = Instant::now();
+	}
+}
+
+#[derive(Debug)]
+struct PeerStoreInner {
+	peers: HashMap<PeerId, PeerInfo>,
+	protocols: Vec<Arc<dyn ProtocolHandle>>,
+	metrics: Option<PeerStoreMetrics>,
+}
+
+impl PeerStoreInner {
+	fn is_banned(&self, peer_id: &PeerId) -> bool {
+		self.peers.get(peer_id).map_or(false, |info| info.is_banned())
+	}
+
+	fn register_protocol(&mut self, protocol_handle: Arc<dyn ProtocolHandle>) {
+		self.protocols.push(protocol_handle);
+	}
+
+	fn report_disconnect(&mut self, peer_id: PeerId) {
+		let peer_info = self.peers.entry(peer_id).or_default();
+		peer_info.add_reputation(DISCONNECT_REPUTATION_CHANGE);
+
+		log::trace!(
+			target: LOG_TARGET,
+			"Peer {} disconnected, reputation: {:+} to {}",
+			peer_id,
+			DISCONNECT_REPUTATION_CHANGE,
+			peer_info.reputation,
+		);
+	}
+
+	fn report_peer(&mut self, peer_id: PeerId, change: ReputationChange) {
+		let peer_info = self.peers.entry(peer_id).or_default();
+		let was_banned = peer_info.is_banned();
+		peer_info.add_reputation(change.value);
+
+		log::trace!(
+			target: LOG_TARGET,
+			"Report {}: {:+} to {}. Reason: {}.",
+			peer_id,
+			change.value,
+			peer_info.reputation,
+			change.reason,
+		);
+
+		if !peer_info.is_banned() {
+			if was_banned {
+				log::info!(
+					target: LOG_TARGET,
+					"Peer {} is now unbanned: {:+} to {}. Reason: {}.",
+					peer_id,
+					change.value,
+					peer_info.reputation,
+					change.reason,
+				);
+			}
+			return;
+		}
+
+		// Peer is currently banned, disconnect it from all protocols.
+		self.protocols.iter().for_each(|handle| handle.disconnect_peer(peer_id.into()));
+
+		// The peer is banned for the first time.
+		if !was_banned {
+			log::warn!(
+				target: LOG_TARGET,
+				"Report {}: {:+} to {}. Reason: {}. Banned, disconnecting.",
+				peer_id,
+				change.value,
+				peer_info.reputation,
+				change.reason,
+			);
+			return;
+		}
+
+		// The peer was already banned and it got another negative report.
+		// This may happen during a batch report.
+		if change.value < 0 {
+			log::debug!(
+				target: LOG_TARGET,
+				"Report {}: {:+} to {}. Reason: {}. Misbehaved during the ban threshold.",
+				peer_id,
+				change.value,
+				peer_info.reputation,
+				change.reason,
+			);
+		}
+	}
+
+	fn set_peer_role(&mut self, peer_id: &PeerId, role: ObservedRole) {
+		log::trace!(target: LOG_TARGET, "Set {peer_id} role to {role:?}");
+
+		match self.peers.entry(*peer_id) {
+			Entry::Occupied(mut entry) => {
+				entry.get_mut().role = Some(role);
+			},
+			Entry::Vacant(entry) => {
+				entry.insert(PeerInfo { role: Some(role), ..Default::default() });
+			},
+		}
+	}
+
+	fn peer_reputation(&self, peer_id: &PeerId) -> i32 {
+		self.peers.get(peer_id).map_or(0, |info| info.reputation)
+	}
+
+	fn peer_role(&self, peer_id: &PeerId) -> Option<ObservedRole> {
+		self.peers.get(peer_id).map_or(None, |info| info.role)
+	}
+
+	fn outgoing_candidates(&self, count: usize, ignored: HashSet<PeerId>) -> Vec<PeerId> {
+		let mut candidates = self
+			.peers
+			.iter()
+			.filter_map(|(peer_id, info)| {
+				(!info.is_banned() && !ignored.contains(peer_id)).then_some((*peer_id, *info))
+			})
+			.collect::<Vec<_>>();
+		let count = std::cmp::min(count, candidates.len());
+		candidates.partial_sort(count, |(_, info1), (_, info2)| info1.cmp(info2));
+		candidates.iter().take(count).map(|(peer_id, _)| *peer_id).collect()
+
+		// TODO: keep the peers sorted (in a "bi-multi-map"?) to not repeat sorting every time.
+	}
+
+	fn progress_time(&mut self, seconds_passed: u64) {
+		if seconds_passed == 0 {
+			return;
+		}
+
+		// Drive reputation values towards 0.
+		self.peers
+			.iter_mut()
+			.for_each(|(_, info)| info.decay_reputation(seconds_passed));
+
+		// Retain only entries with non-zero reputation values or not expired ones.
+		let now = Instant::now();
+		let mut num_banned_peers: u64 = 0;
+		self.peers.retain(|_, info| {
+			if info.is_banned() {
+				num_banned_peers += 1;
+			}
+
+			info.reputation != 0 || info.last_updated + FORGET_AFTER > now
+		});
+
+		if let Some(metrics) = &self.metrics {
+			metrics.num_discovered.set(self.peers.len() as u64);
+			metrics.num_banned_peers.set(num_banned_peers);
+		}
+	}
+
+	fn add_known_peer(&mut self, peer_id: PeerId) {
+		match self.peers.entry(peer_id) {
+			Entry::Occupied(mut e) => {
+				trace!(
+					target: LOG_TARGET,
+					"Trying to add an already known peer {peer_id}, bumping `last_updated`.",
+				);
+				e.get_mut().bump_last_updated();
+			},
+			Entry::Vacant(e) => {
+				trace!(target: LOG_TARGET, "Adding a new known peer {peer_id}.");
+				e.insert(PeerInfo::default());
+			},
+		}
+	}
+}
+
+/// Worker part of [`PeerStoreHandle`]
+#[derive(Debug)]
+pub struct PeerStore {
+	inner: Arc<Mutex<PeerStoreInner>>,
+}
+
+impl PeerStore {
+	/// Create a new peer store from the list of bootnodes.
+	pub fn new(bootnodes: Vec<PeerId>, metrics_registry: Option<Registry>) -> Self {
+		let metrics = if let Some(registry) = &metrics_registry {
+			PeerStoreMetrics::register(registry)
+				.map_err(|err| {
+					log::error!(target: LOG_TARGET, "Failed to register peer set metrics: {}", err);
+					err
+				})
+				.ok()
+		} else {
+			None
+		};
+
+		PeerStore {
+			inner: Arc::new(Mutex::new(PeerStoreInner {
+				peers: bootnodes
+					.into_iter()
+					.map(|peer_id| (peer_id, PeerInfo::default()))
+					.collect(),
+				protocols: Vec::new(),
+				metrics,
+			})),
+		}
+	}
+
+	/// Get `PeerStoreHandle`.
+	pub fn handle(&self) -> PeerStoreHandle {
+		PeerStoreHandle { inner: self.inner.clone() }
+	}
+
+	/// Drive the `PeerStore`, decaying reputation values over time and removing expired entries.
+	pub async fn run(self) {
+		let started = Instant::now();
+		let mut latest_time_update = started;
+
+		loop {
+			let now = Instant::now();
+			// We basically do `(now - self.latest_update).as_secs()`, except that by the way we do
+			// it we know that we're not going to miss seconds because of rounding to integers.
+			let seconds_passed = {
+				let elapsed_latest = latest_time_update - started;
+				let elapsed_now = now - started;
+				latest_time_update = now;
+				elapsed_now.as_secs() - elapsed_latest.as_secs()
+			};
+
+			self.inner.lock().progress_time(seconds_passed);
+			let _ = Delay::new(Duration::from_secs(1)).await;
+		}
+	}
+}
+
+#[async_trait::async_trait]
+impl PeerStoreT for PeerStore {
+	fn handle(&self) -> Arc<dyn PeerStoreProvider> {
+		Arc::new(self.handle())
+	}
+
+	async fn run(self) {
+		self.run().await;
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::{PeerInfo, PeerStore, PeerStoreProvider};
+
+	#[test]
+	fn decaying_zero_reputation_yields_zero() {
+		let mut peer_info = PeerInfo::default();
+		assert_eq!(peer_info.reputation, 0);
+
+		peer_info.decay_reputation(1);
+		assert_eq!(peer_info.reputation, 0);
+
+		peer_info.decay_reputation(100_000);
+		assert_eq!(peer_info.reputation, 0);
+	}
+
+	#[test]
+	fn decaying_positive_reputation_decreases_it() {
+		const INITIAL_REPUTATION: i32 = 100;
+
+		let mut peer_info = PeerInfo::default();
+		peer_info.reputation = INITIAL_REPUTATION;
+
+		peer_info.decay_reputation(1);
+		assert!(peer_info.reputation >= 0);
+		assert!(peer_info.reputation < INITIAL_REPUTATION);
+	}
+
+	#[test]
+	fn decaying_negative_reputation_increases_it() {
+		const INITIAL_REPUTATION: i32 = -100;
+
+		let mut peer_info = PeerInfo::default();
+		peer_info.reputation = INITIAL_REPUTATION;
+
+		peer_info.decay_reputation(1);
+		assert!(peer_info.reputation <= 0);
+		assert!(peer_info.reputation > INITIAL_REPUTATION);
+	}
+
+	#[test]
+	fn decaying_max_reputation_finally_yields_zero() {
+		const INITIAL_REPUTATION: i32 = i32::MAX;
+		const SECONDS: u64 = 3544;
+
+		let mut peer_info = PeerInfo::default();
+		peer_info.reputation = INITIAL_REPUTATION;
+
+		peer_info.decay_reputation(SECONDS / 2);
+		assert!(peer_info.reputation > 0);
+
+		peer_info.decay_reputation(SECONDS / 2);
+		assert_eq!(peer_info.reputation, 0);
+	}
+
+	#[test]
+	fn decaying_min_reputation_finally_yields_zero() {
+		const INITIAL_REPUTATION: i32 = i32::MIN;
+		const SECONDS: u64 = 3544;
+
+		let mut peer_info = PeerInfo::default();
+		peer_info.reputation = INITIAL_REPUTATION;
+
+		peer_info.decay_reputation(SECONDS / 2);
+		assert!(peer_info.reputation < 0);
+
+		peer_info.decay_reputation(SECONDS / 2);
+		assert_eq!(peer_info.reputation, 0);
+	}
+
+	#[test]
+	fn report_banned_peers() {
+		let peer_a = pezsc_network_types::PeerId::random();
+		let peer_b = pezsc_network_types::PeerId::random();
+		let peer_c = pezsc_network_types::PeerId::random();
+
+		let metrics_registry = prometheus_endpoint::Registry::new();
+		let peerstore = PeerStore::new(
+			vec![peer_a, peer_b, peer_c].into_iter().map(Into::into).collect(),
+			Some(metrics_registry),
+		);
+		let metrics = peerstore.inner.lock().metrics.as_ref().unwrap().clone();
+		let handle = peerstore.handle();
+
+		// Check initial state. Advance time to propagate peers.
+		handle.inner.lock().progress_time(1);
+		assert_eq!(metrics.num_discovered.get(), 3);
+		assert_eq!(metrics.num_banned_peers.get(), 0);
+
+		// Report 2 peers with a negative reputation.
+		handle.report_peer(
+			peer_a,
+			pezsc_network_common::types::ReputationChange { value: i32::MIN, reason: "test".into() },
+		);
+		handle.report_peer(
+			peer_b,
+			pezsc_network_common::types::ReputationChange { value: i32::MIN, reason: "test".into() },
+		);
+
+		// Advance time to propagate banned peers.
+		handle.inner.lock().progress_time(1);
+		assert_eq!(metrics.num_discovered.get(), 3);
+		assert_eq!(metrics.num_banned_peers.get(), 2);
+	}
+}

bizinikiwi/client/network/src/protocol.rs

@@ -0,0 +1,410 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::{
+	config, error,
+	peer_store::PeerStoreProvider,
+	protocol_controller::{self, SetId},
+	service::{metrics::NotificationMetrics, traits::Direction},
+	types::ProtocolName,
+};
+
+use codec::Encode;
+use libp2p::{
+	core::{transport::PortUse, Endpoint},
+	swarm::{
+		behaviour::FromSwarm, ConnectionDenied, ConnectionId, NetworkBehaviour, THandler,
+		THandlerInEvent, THandlerOutEvent, ToSwarm,
+	},
+	Multiaddr, PeerId,
+};
+use log::{debug, warn};
+
+use codec::DecodeAll;
+use pezsc_network_common::{role::Roles, types::ReputationChange};
+use pezsc_utils::mpsc::TracingUnboundedReceiver;
+use pezsp_runtime::traits::Block as BlockT;
+
+use std::{collections::HashSet, iter, sync::Arc, task::Poll};
+
+use notifications::{Notifications, NotificationsOut};
+
+pub(crate) use notifications::ProtocolHandle;
+
+pub use notifications::{notification_service, NotificationsSink, ProtocolHandlePair, Ready};
+
+mod notifications;
+
+pub mod message;
+
+// Log target for this file.
+const LOG_TARGET: &str = "sub-libp2p";
+
+/// Identifier of the peerset for the block announces protocol.
+const HARDCODED_PEERSETS_SYNC: SetId = SetId::from(0);
+
+// Lock must always be taken in order declared here.
+pub struct Protocol<B: BlockT> {
+	/// Handles opening the unique substream and sending and receiving raw messages.
+	behaviour: Notifications,
+	/// List of notifications protocols that have been registered.
+	notification_protocols: Vec<ProtocolName>,
+	/// Handle to `PeerStore`.
+	peer_store_handle: Arc<dyn PeerStoreProvider>,
+	/// Streams for peers whose handshake couldn't be determined.
+	bad_handshake_streams: HashSet<PeerId>,
+	sync_handle: ProtocolHandle,
+	_marker: std::marker::PhantomData<B>,
+}
+
+impl<B: BlockT> Protocol<B> {
+	/// Create a new instance.
+	pub(crate) fn new(
+		roles: Roles,
+		notification_metrics: NotificationMetrics,
+		notification_protocols: Vec<config::NonDefaultSetConfig>,
+		block_announces_protocol: config::NonDefaultSetConfig,
+		peer_store_handle: Arc<dyn PeerStoreProvider>,
+		protocol_controller_handles: Vec<protocol_controller::ProtocolHandle>,
+		from_protocol_controllers: TracingUnboundedReceiver<protocol_controller::Message>,
+	) -> error::Result<(Self, Vec<ProtocolHandle>)> {
+		let (behaviour, notification_protocols, handles) = {
+			let installed_protocols = iter::once(block_announces_protocol.protocol_name().clone())
+				.chain(notification_protocols.iter().map(|p| p.protocol_name().clone()))
+				.collect::<Vec<_>>();
+
+			// NOTE: Block announcement protocol is still very much hardcoded into
+			// `Protocol`. 	This protocol must be the first notification protocol given to
+			// `Notifications`
+			let (protocol_configs, mut handles): (Vec<_>, Vec<_>) = iter::once({
+				let config = notifications::ProtocolConfig {
+					name: block_announces_protocol.protocol_name().clone(),
+					fallback_names: block_announces_protocol.fallback_names().cloned().collect(),
+					handshake: block_announces_protocol.handshake().as_ref().unwrap().to_vec(),
+					max_notification_size: block_announces_protocol.max_notification_size(),
+				};
+
+				let (handle, command_stream) =
+					block_announces_protocol.take_protocol_handle().split();
+
+				((config, handle.clone(), command_stream), handle)
+			})
+			.chain(notification_protocols.into_iter().map(|s| {
+				let config = notifications::ProtocolConfig {
+					name: s.protocol_name().clone(),
+					fallback_names: s.fallback_names().cloned().collect(),
+					handshake: s.handshake().as_ref().map_or(roles.encode(), |h| (*h).to_vec()),
+					max_notification_size: s.max_notification_size(),
+				};
+
+				let (handle, command_stream) = s.take_protocol_handle().split();
+
+				((config, handle.clone(), command_stream), handle)
+			}))
+			.unzip();
+
+			handles.iter_mut().for_each(|handle| {
+				handle.set_metrics(notification_metrics.clone());
+			});
+
+			protocol_configs.iter().enumerate().for_each(|(i, (p, _, _))| {
+				debug!(target: LOG_TARGET, "Notifications protocol {:?}: {}", SetId::from(i), p.name);
+			});
+
+			(
+				Notifications::new(
+					protocol_controller_handles,
+					from_protocol_controllers,
+					notification_metrics,
+					protocol_configs.into_iter(),
+				),
+				installed_protocols,
+				handles,
+			)
+		};
+
+		let protocol = Self {
+			behaviour,
+			sync_handle: handles[0].clone(),
+			peer_store_handle,
+			notification_protocols,
+			bad_handshake_streams: HashSet::new(),
+			// TODO: remove when `BlockAnnouncesHandshake` is moved away from `Protocol`
+			_marker: Default::default(),
+		};
+
+		Ok((protocol, handles))
+	}
+
+	pub fn num_sync_peers(&self) -> usize {
+		self.sync_handle.num_peers()
+	}
+
+	/// Returns the list of all the peers we have an open channel to.
+	pub fn open_peers(&self) -> impl Iterator<Item = &PeerId> {
+		self.behaviour.open_peers()
+	}
+
+	/// Disconnects the given peer if we are connected to it.
+	pub fn disconnect_peer(&mut self, peer_id: &PeerId, protocol_name: ProtocolName) {
+		if let Some(position) = self.notification_protocols.iter().position(|p| *p == protocol_name)
+		{
+			self.behaviour.disconnect_peer(peer_id, SetId::from(position));
+		} else {
+			warn!(target: LOG_TARGET, "disconnect_peer() with invalid protocol name")
+		}
+	}
+
+	/// Check if role is available for `peer_id` by attempt to decode the handshake to roles and if
+	/// that fails, check if the role has been registered to `PeerStore`.
+	fn role_available(&self, peer_id: &PeerId, handshake: &Vec<u8>) -> bool {
+		match Roles::decode_all(&mut &handshake[..]) {
+			Ok(_) => true,
+			Err(_) => self.peer_store_handle.peer_role(&((*peer_id).into())).is_some(),
+		}
+	}
+}
+
+/// Outcome of an incoming custom message.
+#[derive(Debug)]
+#[must_use]
+pub enum CustomMessageOutcome {
+	/// Notification protocols have been opened with a remote.
+	NotificationStreamOpened {
+		remote: PeerId,
+		// protocol: ProtocolName,
+		set_id: SetId,
+		/// Direction of the stream.
+		direction: Direction,
+		/// See [`crate::Event::NotificationStreamOpened::negotiated_fallback`].
+		negotiated_fallback: Option<ProtocolName>,
+		/// Received handshake.
+		received_handshake: Vec<u8>,
+		/// Notification sink.
+		notifications_sink: NotificationsSink,
+	},
+	/// The [`NotificationsSink`] of some notification protocols need an update.
+	NotificationStreamReplaced {
+		// Peer ID.
+		remote: PeerId,
+		/// Set ID.
+		set_id: SetId,
+		/// New notification sink.
+		notifications_sink: NotificationsSink,
+	},
+	/// Notification protocols have been closed with a remote.
+	NotificationStreamClosed {
+		// Peer ID.
+		remote: PeerId,
+		/// Set ID.
+		set_id: SetId,
+	},
+	/// Messages have been received on one or more notifications protocols.
+	NotificationsReceived {
+		// Peer ID.
+		remote: PeerId,
+		/// Set ID.
+		set_id: SetId,
+		/// Received notification.
+		notification: Vec<u8>,
+	},
+}
+
+impl<B: BlockT> NetworkBehaviour for Protocol<B> {
+	type ConnectionHandler = <Notifications as NetworkBehaviour>::ConnectionHandler;
+	type ToSwarm = CustomMessageOutcome;
+
+	fn handle_established_inbound_connection(
+		&mut self,
+		connection_id: ConnectionId,
+		peer: PeerId,
+		local_addr: &Multiaddr,
+		remote_addr: &Multiaddr,
+	) -> Result<THandler<Self>, ConnectionDenied> {
+		self.behaviour.handle_established_inbound_connection(
+			connection_id,
+			peer,
+			local_addr,
+			remote_addr,
+		)
+	}
+
+	fn handle_established_outbound_connection(
+		&mut self,
+		connection_id: ConnectionId,
+		peer: PeerId,
+		addr: &Multiaddr,
+		role_override: Endpoint,
+		port_use: PortUse,
+	) -> Result<THandler<Self>, ConnectionDenied> {
+		self.behaviour.handle_established_outbound_connection(
+			connection_id,
+			peer,
+			addr,
+			role_override,
+			port_use,
+		)
+	}
+
+	fn handle_pending_outbound_connection(
+		&mut self,
+		_connection_id: ConnectionId,
+		_maybe_peer: Option<PeerId>,
+		_addresses: &[Multiaddr],
+		_effective_role: Endpoint,
+	) -> Result<Vec<Multiaddr>, ConnectionDenied> {
+		// Only `Discovery::handle_pending_outbound_connection` must be returning addresses to
+		// ensure that we don't return unwanted addresses.
+		Ok(Vec::new())
+	}
+
+	fn on_swarm_event(&mut self, event: FromSwarm) {
+		self.behaviour.on_swarm_event(event);
+	}
+
+	fn on_connection_handler_event(
+		&mut self,
+		peer_id: PeerId,
+		connection_id: ConnectionId,
+		event: THandlerOutEvent<Self>,
+	) {
+		self.behaviour.on_connection_handler_event(peer_id, connection_id, event);
+	}
+
+	fn poll(
+		&mut self,
+		cx: &mut std::task::Context,
+	) -> Poll<ToSwarm<Self::ToSwarm, THandlerInEvent<Self>>> {
+		let event = match self.behaviour.poll(cx) {
+			Poll::Pending => return Poll::Pending,
+			Poll::Ready(ToSwarm::GenerateEvent(ev)) => ev,
+			Poll::Ready(event) => {
+				return Poll::Ready(event.map_out(|_| {
+					unreachable!("`GenerateEvent` is handled in a branch above; qed")
+				}));
+			},
+		};
+
+		let outcome = match event {
+			NotificationsOut::CustomProtocolOpen {
+				peer_id,
+				set_id,
+				direction,
+				received_handshake,
+				notifications_sink,
+				negotiated_fallback,
+				..
+			} =>
+				if set_id == HARDCODED_PEERSETS_SYNC {
+					let _ = self.sync_handle.report_substream_opened(
+						peer_id,
+						direction,
+						received_handshake,
+						negotiated_fallback,
+						notifications_sink,
+					);
+					None
+				} else {
+					match self.role_available(&peer_id, &received_handshake) {
+						true => Some(CustomMessageOutcome::NotificationStreamOpened {
+							remote: peer_id,
+							set_id,
+							direction,
+							negotiated_fallback,
+							received_handshake,
+							notifications_sink,
+						}),
+						false => {
+							self.bad_handshake_streams.insert(peer_id);
+							None
+						},
+					}
+				},
+			NotificationsOut::CustomProtocolReplaced { peer_id, notifications_sink, set_id } =>
+				if set_id == HARDCODED_PEERSETS_SYNC {
+					let _ = self
+						.sync_handle
+						.report_notification_sink_replaced(peer_id, notifications_sink);
+					None
+				} else {
+					(!self.bad_handshake_streams.contains(&peer_id)).then_some(
+						CustomMessageOutcome::NotificationStreamReplaced {
+							remote: peer_id,
+							set_id,
+							notifications_sink,
+						},
+					)
+				},
+			NotificationsOut::CustomProtocolClosed { peer_id, set_id } => {
+				if set_id == HARDCODED_PEERSETS_SYNC {
+					let _ = self.sync_handle.report_substream_closed(peer_id);
+					None
+				} else {
+					(!self.bad_handshake_streams.remove(&peer_id)).then_some(
+						CustomMessageOutcome::NotificationStreamClosed { remote: peer_id, set_id },
+					)
+				}
+			},
+			NotificationsOut::Notification { peer_id, set_id, message } => {
+				if set_id == HARDCODED_PEERSETS_SYNC {
+					let _ = self
+						.sync_handle
+						.report_notification_received(peer_id, message.freeze().into());
+					None
+				} else {
+					(!self.bad_handshake_streams.contains(&peer_id)).then_some(
+						CustomMessageOutcome::NotificationsReceived {
+							remote: peer_id,
+							set_id,
+							notification: message.freeze().into(),
+						},
+					)
+				}
+			},
+
+			NotificationsOut::ProtocolMisbehavior { peer_id, set_id } => {
+				let index: usize = set_id.into();
+				let protocol_name = self.notification_protocols.get(index);
+
+				debug!(
+					target: LOG_TARGET,
+					"Received unexpected data on outbound notification stream from peer {:?} on protocol {:?}",
+					peer_id,
+					protocol_name
+				);
+
+				self.peer_store_handle.report_peer(
+					peer_id.into(),
+					ReputationChange::new_fatal(
+						"Received unexpected data on outbound notification stream",
+					),
+				);
+
+				None
+			},
+		};
+
+		match outcome {
+			Some(event) => Poll::Ready(ToSwarm::GenerateEvent(event)),
+			None => {
+				cx.waker().wake_by_ref();
+				Poll::Pending
+			},
+		}
+	}
+}

bizinikiwi/client/network/src/protocol/message.rs

@@ -0,0 +1,240 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Network packet message types. These get serialized and put into the lower level protocol
+//! payload.
+
+use codec::{Decode, Encode};
+use pezsc_client_api::StorageProof;
+use pezsc_network_common::message::RequestId;
+
+/// Remote call response.
+#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+#[allow(dead_code)]
+pub struct RemoteCallResponse {
+	/// Id of a request this response was made for.
+	pub id: RequestId,
+	/// Execution proof.
+	pub proof: StorageProof,
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+#[allow(dead_code)]
+/// Remote read response.
+pub struct RemoteReadResponse {
+	/// Id of a request this response was made for.
+	pub id: RequestId,
+	/// Read proof.
+	pub proof: StorageProof,
+}
+
+/// Generic types.
+pub mod generic {
+	use codec::{Decode, Encode, Input};
+	use pezsc_client_api::StorageProof;
+	use pezsc_network_common::{message::RequestId, role::Roles};
+	use pezsp_runtime::ConsensusEngineId;
+
+	/// Consensus is mostly opaque to us
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	#[allow(dead_code)]
+	pub struct ConsensusMessage {
+		/// Identifies consensus engine.
+		pub protocol: ConsensusEngineId,
+		/// Message payload.
+		pub data: Vec<u8>,
+	}
+
+	/// Status sent on connection.
+	// TODO https://github.com/pezkuwichain/kurdistan-sdk/issues/24: replace the `Status`
+	// struct with this one, after waiting a few releases beyond `NetworkSpecialization`'s
+	// removal (https://github.com/pezkuwichain/kurdistan-sdk/issues/55)
+	//
+	// and set MIN_VERSION to 6.
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	#[allow(dead_code)]
+	pub struct CompactStatus<Hash, Number> {
+		/// Protocol version.
+		pub version: u32,
+		/// Minimum supported version.
+		pub min_supported_version: u32,
+		/// Supported roles.
+		pub roles: Roles,
+		/// Best block number.
+		pub best_number: Number,
+		/// Best block hash.
+		pub best_hash: Hash,
+		/// Genesis block hash.
+		pub genesis_hash: Hash,
+	}
+
+	/// Status sent on connection.
+	#[derive(Debug, PartialEq, Eq, Clone, Encode)]
+	#[allow(dead_code)]
+	pub struct Status<Hash, Number> {
+		/// Protocol version.
+		pub version: u32,
+		/// Minimum supported version.
+		pub min_supported_version: u32,
+		/// Supported roles.
+		pub roles: Roles,
+		/// Best block number.
+		pub best_number: Number,
+		/// Best block hash.
+		pub best_hash: Hash,
+		/// Genesis block hash.
+		pub genesis_hash: Hash,
+		/// DEPRECATED. Chain-specific status.
+		pub chain_status: Vec<u8>,
+	}
+
+	impl<Hash: Decode, Number: Decode> Decode for Status<Hash, Number> {
+		fn decode<I: Input>(value: &mut I) -> Result<Self, codec::Error> {
+			const LAST_CHAIN_STATUS_VERSION: u32 = 5;
+			let compact = CompactStatus::decode(value)?;
+			let chain_status = match <Vec<u8>>::decode(value) {
+				Ok(v) => v,
+				Err(e) =>
+					if compact.version <= LAST_CHAIN_STATUS_VERSION {
+						return Err(e);
+					} else {
+						Vec::new()
+					},
+			};
+
+			let CompactStatus {
+				version,
+				min_supported_version,
+				roles,
+				best_number,
+				best_hash,
+				genesis_hash,
+			} = compact;
+
+			Ok(Self {
+				version,
+				min_supported_version,
+				roles,
+				best_number,
+				best_hash,
+				genesis_hash,
+				chain_status,
+			})
+		}
+	}
+
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	#[allow(dead_code)]
+	/// Remote call request.
+	pub struct RemoteCallRequest<H> {
+		/// Unique request id.
+		pub id: RequestId,
+		/// Block at which to perform call.
+		pub block: H,
+		/// Method name.
+		pub method: String,
+		/// Call data.
+		pub data: Vec<u8>,
+	}
+
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	#[allow(dead_code)]
+	/// Remote storage read request.
+	pub struct RemoteReadRequest<H> {
+		/// Unique request id.
+		pub id: RequestId,
+		/// Block at which to perform call.
+		pub block: H,
+		/// Storage key.
+		pub keys: Vec<Vec<u8>>,
+	}
+
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	#[allow(dead_code)]
+	/// Remote storage read child request.
+	pub struct RemoteReadChildRequest<H> {
+		/// Unique request id.
+		pub id: RequestId,
+		/// Block at which to perform call.
+		pub block: H,
+		/// Child Storage key.
+		pub storage_key: Vec<u8>,
+		/// Storage key.
+		pub keys: Vec<Vec<u8>>,
+	}
+
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	#[allow(dead_code)]
+	/// Remote header request.
+	pub struct RemoteHeaderRequest<N> {
+		/// Unique request id.
+		pub id: RequestId,
+		/// Block number to request header for.
+		pub block: N,
+	}
+
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	#[allow(dead_code)]
+	/// Remote header response.
+	pub struct RemoteHeaderResponse<Header> {
+		/// Id of a request this response was made for.
+		pub id: RequestId,
+		/// Header. None if proof generation has failed (e.g. header is unknown).
+		pub header: Option<Header>,
+		/// Header proof.
+		pub proof: StorageProof,
+	}
+
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	#[allow(dead_code)]
+	/// Remote changes request.
+	pub struct RemoteChangesRequest<H> {
+		/// Unique request id.
+		pub id: RequestId,
+		/// Hash of the first block of the range (including first) where changes are requested.
+		pub first: H,
+		/// Hash of the last block of the range (including last) where changes are requested.
+		pub last: H,
+		/// Hash of the first block for which the requester has the changes trie root. All other
+		/// affected roots must be proved.
+		pub min: H,
+		/// Hash of the last block that we can use when querying changes.
+		pub max: H,
+		/// Storage child node key which changes are requested.
+		pub storage_key: Option<Vec<u8>>,
+		/// Storage key which changes are requested.
+		pub key: Vec<u8>,
+	}
+
+	#[derive(Debug, PartialEq, Eq, Clone, Encode, Decode)]
+	#[allow(dead_code)]
+	/// Remote changes response.
+	pub struct RemoteChangesResponse<N, H> {
+		/// Id of a request this response was made for.
+		pub id: RequestId,
+		/// Proof has been generated using block with this number as a max block. Should be
+		/// less than or equal to the RemoteChangesRequest::max block number.
+		pub max: N,
+		/// Changes proof.
+		pub proof: Vec<Vec<u8>>,
+		/// Changes tries roots missing on the requester' node.
+		pub roots: Vec<(N, H)>,
+		/// Missing changes tries roots proof.
+		pub roots_proof: StorageProof,
+	}
+}

bizinikiwi/client/network/src/protocol/notifications.rs

@@ -0,0 +1,34 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Implementation of libp2p's `NetworkBehaviour` trait that establishes communications and opens
+//! notifications substreams.
+
+pub use self::{
+	behaviour::{Notifications, NotificationsOut, ProtocolConfig},
+	handler::{NotificationsSink, Ready},
+	service::{notification_service, ProtocolHandlePair},
+};
+
+pub(crate) use self::service::ProtocolHandle;
+
+mod behaviour;
+mod handler;
+mod service;
+mod tests;
+mod upgrade;

bizinikiwi/client/network/src/protocol/notifications/service/metrics.rs

@@ -0,0 +1,55 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::{service::metrics::NotificationMetrics, types::ProtocolName};
+
+/// Register opened substream to Prometheus.
+pub fn register_substream_opened(metrics: &Option<NotificationMetrics>, protocol: &ProtocolName) {
+	if let Some(metrics) = metrics {
+		metrics.register_substream_opened(&protocol);
+	}
+}
+
+/// Register closed substream to Prometheus.
+pub fn register_substream_closed(metrics: &Option<NotificationMetrics>, protocol: &ProtocolName) {
+	if let Some(metrics) = metrics {
+		metrics.register_substream_closed(&protocol);
+	}
+}
+
+/// Register sent notification to Prometheus.
+pub fn register_notification_sent(
+	metrics: &Option<std::sync::Arc<NotificationMetrics>>,
+	protocol: &ProtocolName,
+	size: usize,
+) {
+	if let Some(metrics) = metrics {
+		metrics.register_notification_sent(protocol, size);
+	}
+}
+
+/// Register received notification to Prometheus.
+pub fn register_notification_received(
+	metrics: &Option<NotificationMetrics>,
+	protocol: &ProtocolName,
+	size: usize,
+) {
+	if let Some(metrics) = metrics {
+		metrics.register_notification_received(protocol, size);
+	}
+}

bizinikiwi/client/network/src/protocol/notifications/service/mod.rs

@@ -0,0 +1,656 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Notification service implementation.
+
+use crate::{
+	error,
+	protocol::notifications::handler::NotificationsSink,
+	service::{
+		metrics::NotificationMetrics,
+		traits::{
+			Direction, MessageSink, NotificationEvent, NotificationService, ValidationResult,
+		},
+	},
+	types::ProtocolName,
+};
+
+use futures::{
+	stream::{FuturesUnordered, Stream},
+	StreamExt,
+};
+use libp2p::PeerId;
+use parking_lot::Mutex;
+use tokio::sync::{mpsc, oneshot};
+use tokio_stream::wrappers::ReceiverStream;
+
+use pezsc_utils::mpsc::{tracing_unbounded, TracingUnboundedReceiver, TracingUnboundedSender};
+
+use std::{collections::HashMap, fmt::Debug, sync::Arc};
+
+pub(crate) mod metrics;
+
+#[cfg(test)]
+mod tests;
+
+/// Logging target for the file.
+const LOG_TARGET: &str = "sub-libp2p::notification::service";
+
+/// Default command queue size.
+const COMMAND_QUEUE_SIZE: usize = 64;
+
+/// Type representing subscribers of a notification protocol.
+type Subscribers = Arc<Mutex<Vec<TracingUnboundedSender<InnerNotificationEvent>>>>;
+
+/// Type representing a distributable message sink.
+/// Detached message sink must carry the protocol name for registering metrics.
+///
+/// See documentation for [`PeerContext`] for more details.
+type NotificationSink = Arc<Mutex<(NotificationsSink, ProtocolName)>>;
+
+#[async_trait::async_trait]
+impl MessageSink for NotificationSink {
+	/// Send synchronous `notification` to the peer associated with this [`MessageSink`].
+	fn send_sync_notification(&self, notification: Vec<u8>) {
+		let sink = self.lock();
+
+		metrics::register_notification_sent(sink.0.metrics(), &sink.1, notification.len());
+		sink.0.send_sync_notification(notification);
+	}
+
+	/// Send an asynchronous `notification` to the peer associated with this [`MessageSink`],
+	/// allowing sender to exercise backpressure.
+	///
+	/// Returns an error if the peer does not exist.
+	async fn send_async_notification(&self, notification: Vec<u8>) -> Result<(), error::Error> {
+		// notification sink must be cloned because the lock cannot be held across `.await`
+		// this makes the implementation less efficient but not prohibitively so as the same
+		// method is also used by `NetworkService` when sending notifications.
+		let notification_len = notification.len();
+		let sink = self.lock().clone();
+		let permit = sink
+			.0
+			.reserve_notification()
+			.await
+			.map_err(|_| error::Error::ConnectionClosed)?;
+
+		permit.send(notification).map_err(|_| error::Error::ChannelClosed).inspect(|_| {
+			metrics::register_notification_sent(sink.0.metrics(), &sink.1, notification_len);
+		})
+	}
+}
+
+/// Inner notification event to deal with `NotificationsSinks` without exposing that
+/// implementation detail to [`NotificationService`] consumers.
+#[derive(Debug)]
+enum InnerNotificationEvent {
+	/// Validate inbound substream.
+	ValidateInboundSubstream {
+		/// Peer ID.
+		peer: PeerId,
+
+		/// Received handshake.
+		handshake: Vec<u8>,
+
+		/// `oneshot::Sender` for sending validation result back to `Notifications`
+		result_tx: oneshot::Sender<ValidationResult>,
+	},
+
+	/// Notification substream open to `peer`.
+	NotificationStreamOpened {
+		/// Peer ID.
+		peer: PeerId,
+
+		/// Direction of the substream.
+		direction: Direction,
+
+		/// Received handshake.
+		handshake: Vec<u8>,
+
+		/// Negotiated fallback.
+		negotiated_fallback: Option<ProtocolName>,
+
+		/// Notification sink.
+		sink: NotificationsSink,
+	},
+
+	/// Substream was closed.
+	NotificationStreamClosed {
+		/// Peer ID.
+		peer: PeerId,
+	},
+
+	/// Notification was received from the substream.
+	NotificationReceived {
+		/// Peer ID.
+		peer: PeerId,
+
+		/// Received notification.
+		notification: Vec<u8>,
+	},
+
+	/// Notification sink has been replaced.
+	NotificationSinkReplaced {
+		/// Peer ID.
+		peer: PeerId,
+
+		/// Notification sink.
+		sink: NotificationsSink,
+	},
+}
+
+/// Notification commands.
+///
+/// Sent by the installed protocols to `Notifications` to open/close/modify substreams.
+#[derive(Debug)]
+pub enum NotificationCommand {
+	/// Instruct `Notifications` to open a substream to peer.
+	#[allow(unused)]
+	OpenSubstream(PeerId),
+
+	/// Instruct `Notifications` to close the substream to peer.
+	#[allow(unused)]
+	CloseSubstream(PeerId),
+
+	/// Set handshake for the notifications protocol.
+	SetHandshake(Vec<u8>),
+}
+
+/// Context assigned to each peer.
+///
+/// Contains `NotificationsSink` used by [`NotificationService`] to send notifications
+/// and an additional, distributable `NotificationsSink` which the protocol may acquire
+/// if it wishes to send notifications through `NotificationsSink` directly.
+///
+/// The distributable `NotificationsSink` is wrapped in an `Arc<Mutex<>>` to allow
+/// `NotificationsService` to swap the underlying sink in case it's replaced.
+#[derive(Debug, Clone)]
+struct PeerContext {
+	/// Sink for sending notifications.
+	sink: NotificationsSink,
+
+	/// Distributable notification sink.
+	shared_sink: NotificationSink,
+}
+
+/// Handle that is passed on to the notifications protocol.
+#[derive(Debug)]
+pub struct NotificationHandle {
+	/// Protocol name.
+	protocol: ProtocolName,
+
+	/// TX channel for sending commands to `Notifications`.
+	tx: mpsc::Sender<NotificationCommand>,
+
+	/// RX channel for receiving events from `Notifications`.
+	rx: TracingUnboundedReceiver<InnerNotificationEvent>,
+
+	/// All subscribers of `NotificationEvent`s.
+	subscribers: Subscribers,
+
+	/// Connected peers.
+	peers: HashMap<PeerId, PeerContext>,
+}
+
+impl NotificationHandle {
+	/// Create new [`NotificationHandle`].
+	fn new(
+		protocol: ProtocolName,
+		tx: mpsc::Sender<NotificationCommand>,
+		rx: TracingUnboundedReceiver<InnerNotificationEvent>,
+		subscribers: Arc<Mutex<Vec<TracingUnboundedSender<InnerNotificationEvent>>>>,
+	) -> Self {
+		Self { protocol, tx, rx, subscribers, peers: HashMap::new() }
+	}
+}
+
+#[async_trait::async_trait]
+impl NotificationService for NotificationHandle {
+	/// Instruct `Notifications` to open a new substream for `peer`.
+	async fn open_substream(&mut self, _peer: pezsc_network_types::PeerId) -> Result<(), ()> {
+		todo!("support for opening substreams not implemented yet");
+	}
+
+	/// Instruct `Notifications` to close substream for `peer`.
+	async fn close_substream(&mut self, _peer: pezsc_network_types::PeerId) -> Result<(), ()> {
+		todo!("support for closing substreams not implemented yet, call `NetworkService::disconnect_peer()` instead");
+	}
+
+	/// Send synchronous `notification` to `peer`.
+	fn send_sync_notification(&mut self, peer: &pezsc_network_types::PeerId, notification: Vec<u8>) {
+		if let Some(info) = self.peers.get(&((*peer).into())) {
+			metrics::register_notification_sent(
+				info.sink.metrics(),
+				&self.protocol,
+				notification.len(),
+			);
+
+			let _ = info.sink.send_sync_notification(notification);
+		}
+	}
+
+	/// Send asynchronous `notification` to `peer`, allowing sender to exercise backpressure.
+	async fn send_async_notification(
+		&mut self,
+		peer: &pezsc_network_types::PeerId,
+		notification: Vec<u8>,
+	) -> Result<(), error::Error> {
+		let notification_len = notification.len();
+		let sink = &self
+			.peers
+			.get(&peer.into())
+			.ok_or_else(|| error::Error::PeerDoesntExist((*peer).into()))?
+			.sink;
+
+		sink.reserve_notification()
+			.await
+			.map_err(|_| error::Error::ConnectionClosed)?
+			.send(notification)
+			.map_err(|_| error::Error::ChannelClosed)
+			.inspect(|_| {
+				metrics::register_notification_sent(
+					sink.metrics(),
+					&self.protocol,
+					notification_len,
+				);
+			})
+	}
+
+	/// Set handshake for the notification protocol replacing the old handshake.
+	async fn set_handshake(&mut self, handshake: Vec<u8>) -> Result<(), ()> {
+		log::trace!(target: LOG_TARGET, "{}: set handshake to {handshake:?}", self.protocol);
+
+		self.tx.send(NotificationCommand::SetHandshake(handshake)).await.map_err(|_| ())
+	}
+
+	/// Non-blocking variant of `set_handshake()` that attempts to update the handshake
+	/// and returns an error if the channel is blocked.
+	///
+	/// Technically the function can return an error if the channel to `Notifications` is closed
+	/// but that doesn't happen under normal operation.
+	fn try_set_handshake(&mut self, handshake: Vec<u8>) -> Result<(), ()> {
+		self.tx.try_send(NotificationCommand::SetHandshake(handshake)).map_err(|_| ())
+	}
+
+	/// Get next event from the `Notifications` event stream.
+	async fn next_event(&mut self) -> Option<NotificationEvent> {
+		loop {
+			match self.rx.next().await? {
+				InnerNotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx } =>
+					return Some(NotificationEvent::ValidateInboundSubstream {
+						peer: peer.into(),
+						handshake,
+						result_tx,
+					}),
+				InnerNotificationEvent::NotificationStreamOpened {
+					peer,
+					handshake,
+					negotiated_fallback,
+					direction,
+					sink,
+				} => {
+					self.peers.insert(
+						peer,
+						PeerContext {
+							sink: sink.clone(),
+							shared_sink: Arc::new(Mutex::new((sink, self.protocol.clone()))),
+						},
+					);
+					return Some(NotificationEvent::NotificationStreamOpened {
+						peer: peer.into(),
+						handshake,
+						direction,
+						negotiated_fallback,
+					});
+				},
+				InnerNotificationEvent::NotificationStreamClosed { peer } => {
+					self.peers.remove(&peer);
+					return Some(NotificationEvent::NotificationStreamClosed { peer: peer.into() });
+				},
+				InnerNotificationEvent::NotificationReceived { peer, notification } =>
+					return Some(NotificationEvent::NotificationReceived {
+						peer: peer.into(),
+						notification,
+					}),
+				InnerNotificationEvent::NotificationSinkReplaced { peer, sink } => {
+					match self.peers.get_mut(&peer) {
+						None => log::error!(
+							"{}: notification sink replaced for {peer} but peer does not exist",
+							self.protocol
+						),
+						Some(context) => {
+							context.sink = sink.clone();
+							*context.shared_sink.lock() = (sink.clone(), self.protocol.clone());
+						},
+					}
+				},
+			}
+		}
+	}
+
+	// Clone [`NotificationService`]
+	fn clone(&mut self) -> Result<Box<dyn NotificationService>, ()> {
+		let mut subscribers = self.subscribers.lock();
+
+		let (event_tx, event_rx) = tracing_unbounded(self.rx.name(), 100_000);
+		subscribers.push(event_tx);
+
+		Ok(Box::new(NotificationHandle {
+			protocol: self.protocol.clone(),
+			tx: self.tx.clone(),
+			rx: event_rx,
+			peers: self.peers.clone(),
+			subscribers: self.subscribers.clone(),
+		}))
+	}
+
+	/// Get protocol name.
+	fn protocol(&self) -> &ProtocolName {
+		&self.protocol
+	}
+
+	/// Get message sink of the peer.
+	fn message_sink(&self, peer: &pezsc_network_types::PeerId) -> Option<Box<dyn MessageSink>> {
+		match self.peers.get(&peer.into()) {
+			Some(context) => Some(Box::new(context.shared_sink.clone())),
+			None => None,
+		}
+	}
+}
+
+/// Channel pair which allows `Notifications` to interact with a protocol.
+#[derive(Debug)]
+pub struct ProtocolHandlePair {
+	/// Protocol name.
+	protocol: ProtocolName,
+
+	/// Subscribers of the notification protocol events.
+	subscribers: Subscribers,
+
+	// Receiver for notification commands received from the protocol implementation.
+	rx: mpsc::Receiver<NotificationCommand>,
+}
+
+impl ProtocolHandlePair {
+	/// Create new [`ProtocolHandlePair`].
+	fn new(
+		protocol: ProtocolName,
+		subscribers: Subscribers,
+		rx: mpsc::Receiver<NotificationCommand>,
+	) -> Self {
+		Self { protocol, subscribers, rx }
+	}
+
+	/// Consume `self` and split [`ProtocolHandlePair`] into a handle which allows it to send events
+	/// to the protocol and a stream of commands received from the protocol.
+	pub(crate) fn split(
+		self,
+	) -> (ProtocolHandle, Box<dyn Stream<Item = NotificationCommand> + Send + Unpin>) {
+		(
+			ProtocolHandle::new(self.protocol, self.subscribers),
+			Box::new(ReceiverStream::new(self.rx)),
+		)
+	}
+}
+
+/// Handle that is passed on to `Notifications` and allows it to directly communicate
+/// with the protocol.
+#[derive(Debug, Clone)]
+pub(crate) struct ProtocolHandle {
+	/// Protocol name.
+	protocol: ProtocolName,
+
+	/// Subscribers of the notification protocol.
+	subscribers: Subscribers,
+
+	/// Number of connected peers.
+	num_peers: usize,
+
+	/// Delegate validation to `Peerset`.
+	delegate_to_peerset: bool,
+
+	/// Prometheus metrics.
+	metrics: Option<NotificationMetrics>,
+}
+
+pub(crate) enum ValidationCallResult {
+	WaitForValidation(oneshot::Receiver<ValidationResult>),
+	Delegated,
+}
+
+impl ProtocolHandle {
+	/// Create new [`ProtocolHandle`].
+	fn new(protocol: ProtocolName, subscribers: Subscribers) -> Self {
+		Self { protocol, subscribers, num_peers: 0usize, metrics: None, delegate_to_peerset: false }
+	}
+
+	/// Set metrics.
+	pub fn set_metrics(&mut self, metrics: NotificationMetrics) {
+		self.metrics = Some(metrics);
+	}
+
+	/// Delegate validation to `Peerset`.
+	///
+	/// Protocols that do not do any validation themselves and only rely on `Peerset` handling
+	/// validation can disable protocol-side validation entirely by delegating all validation to
+	/// `Peerset`.
+	pub fn delegate_to_peerset(&mut self, delegate: bool) {
+		self.delegate_to_peerset = delegate;
+	}
+
+	/// Report to the protocol that a substream has been opened and it must be validated by the
+	/// protocol.
+	///
+	/// Return `oneshot::Receiver` which allows `Notifications` to poll for the validation result
+	/// from protocol.
+	pub fn report_incoming_substream(
+		&self,
+		peer: PeerId,
+		handshake: Vec<u8>,
+	) -> Result<ValidationCallResult, ()> {
+		let subscribers = self.subscribers.lock();
+
+		log::trace!(
+			target: LOG_TARGET,
+			"{}: report incoming substream for {peer}, handshake {handshake:?}",
+			self.protocol
+		);
+
+		if self.delegate_to_peerset {
+			return Ok(ValidationCallResult::Delegated);
+		}
+
+		// if there is only one subscriber, `Notifications` can wait directly on the
+		// `oneshot::channel()`'s RX half without indirection
+		if subscribers.len() == 1 {
+			let (result_tx, rx) = oneshot::channel();
+			return subscribers[0]
+				.unbounded_send(InnerNotificationEvent::ValidateInboundSubstream {
+					peer,
+					handshake,
+					result_tx,
+				})
+				.map(|_| ValidationCallResult::WaitForValidation(rx))
+				.map_err(|_| ());
+		}
+
+		// if there are multiple subscribers, create a task which waits for all of the
+		// validations to finish and returns the combined result to `Notifications`
+		let mut results: FuturesUnordered<_> = subscribers
+			.iter()
+			.filter_map(|subscriber| {
+				let (result_tx, rx) = oneshot::channel();
+
+				subscriber
+					.unbounded_send(InnerNotificationEvent::ValidateInboundSubstream {
+						peer,
+						handshake: handshake.clone(),
+						result_tx,
+					})
+					.is_ok()
+					.then_some(rx)
+			})
+			.collect();
+
+		let (tx, rx) = oneshot::channel();
+		tokio::spawn(async move {
+			while let Some(event) = results.next().await {
+				match event {
+					Err(_) | Ok(ValidationResult::Reject) =>
+						return tx.send(ValidationResult::Reject),
+					Ok(ValidationResult::Accept) => {},
+				}
+			}
+
+			return tx.send(ValidationResult::Accept);
+		});
+
+		Ok(ValidationCallResult::WaitForValidation(rx))
+	}
+
+	/// Report to the protocol that a substream has been opened and that it can now use the handle
+	/// to send notifications to the remote peer.
+	pub fn report_substream_opened(
+		&mut self,
+		peer: PeerId,
+		direction: Direction,
+		handshake: Vec<u8>,
+		negotiated_fallback: Option<ProtocolName>,
+		sink: NotificationsSink,
+	) -> Result<(), ()> {
+		metrics::register_substream_opened(&self.metrics, &self.protocol);
+
+		let mut subscribers = self.subscribers.lock();
+		log::trace!(target: LOG_TARGET, "{}: substream opened for {peer:?}", self.protocol);
+
+		subscribers.retain(|subscriber| {
+			subscriber
+				.unbounded_send(InnerNotificationEvent::NotificationStreamOpened {
+					peer,
+					direction,
+					handshake: handshake.clone(),
+					negotiated_fallback: negotiated_fallback.clone(),
+					sink: sink.clone(),
+				})
+				.is_ok()
+		});
+		self.num_peers += 1;
+
+		Ok(())
+	}
+
+	/// Substream was closed.
+	pub fn report_substream_closed(&mut self, peer: PeerId) -> Result<(), ()> {
+		metrics::register_substream_closed(&self.metrics, &self.protocol);
+
+		let mut subscribers = self.subscribers.lock();
+		log::trace!(target: LOG_TARGET, "{}: substream closed for {peer:?}", self.protocol);
+
+		subscribers.retain(|subscriber| {
+			subscriber
+				.unbounded_send(InnerNotificationEvent::NotificationStreamClosed { peer })
+				.is_ok()
+		});
+		self.num_peers -= 1;
+
+		Ok(())
+	}
+
+	/// Notification was received from the substream.
+	pub fn report_notification_received(
+		&mut self,
+		peer: PeerId,
+		notification: Vec<u8>,
+	) -> Result<(), ()> {
+		metrics::register_notification_received(&self.metrics, &self.protocol, notification.len());
+
+		let mut subscribers = self.subscribers.lock();
+		log::trace!(target: LOG_TARGET, "{}: notification received from {peer:?}", self.protocol);
+
+		subscribers.retain(|subscriber| {
+			subscriber
+				.unbounded_send(InnerNotificationEvent::NotificationReceived {
+					peer,
+					notification: notification.clone(),
+				})
+				.is_ok()
+		});
+
+		Ok(())
+	}
+
+	/// Notification sink was replaced.
+	pub fn report_notification_sink_replaced(
+		&mut self,
+		peer: PeerId,
+		sink: NotificationsSink,
+	) -> Result<(), ()> {
+		let mut subscribers = self.subscribers.lock();
+
+		log::trace!(
+			target: LOG_TARGET,
+			"{}: notification sink replaced for {peer:?}",
+			self.protocol
+		);
+
+		subscribers.retain(|subscriber| {
+			subscriber
+				.unbounded_send(InnerNotificationEvent::NotificationSinkReplaced {
+					peer,
+					sink: sink.clone(),
+				})
+				.is_ok()
+		});
+
+		Ok(())
+	}
+
+	/// Get the number of connected peers.
+	pub fn num_peers(&self) -> usize {
+		self.num_peers
+	}
+}
+
+/// Create new (protocol, notification) handle pair.
+///
+/// Handle pair allows `Notifications` and the protocol to communicate with each other directly.
+pub fn notification_service(
+	protocol: ProtocolName,
+) -> (ProtocolHandlePair, Box<dyn NotificationService>) {
+	let (cmd_tx, cmd_rx) = mpsc::channel(COMMAND_QUEUE_SIZE);
+
+	let (event_tx, event_rx) =
+		tracing_unbounded(metric_label_for_protocol(&protocol).leak(), 100_000);
+	let subscribers = Arc::new(Mutex::new(vec![event_tx]));
+
+	(
+		ProtocolHandlePair::new(protocol.clone(), subscribers.clone(), cmd_rx),
+		Box::new(NotificationHandle::new(protocol.clone(), cmd_tx, event_rx, subscribers)),
+	)
+}
+
+// Decorates the mpsc-notification-to-protocol metric with the name of the protocol,
+// to be able to distiguish between different protocols in dashboards.
+fn metric_label_for_protocol(protocol: &ProtocolName) -> String {
+	let protocol_name = protocol.to_string();
+	let keys = protocol_name.split("/").collect::<Vec<_>>();
+	keys.iter()
+		.rev()
+		.take(2) // Last two tokens give the protocol name and version
+		.fold("mpsc-notification-to-protocol".into(), |acc, val| format!("{}-{}", acc, val))
+}

bizinikiwi/client/network/src/protocol/notifications/service/tests.rs

@@ -0,0 +1,844 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use super::*;
+use crate::protocol::notifications::handler::{
+	NotificationsSinkMessage, ASYNC_NOTIFICATIONS_BUFFER_SIZE,
+};
+
+use std::future::Future;
+
+#[tokio::test]
+async fn validate_and_accept_substream() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (handle, _stream) = proto.split();
+
+	let peer_id = PeerId::random();
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+}
+
+#[tokio::test]
+async fn substream_opened() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (sink, _, _) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+
+	let peer_id = PeerId::random();
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	if let Some(NotificationEvent::NotificationStreamOpened {
+		peer,
+		negotiated_fallback,
+		handshake,
+		direction,
+	}) = notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(negotiated_fallback, None);
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		assert_eq!(direction, Direction::Inbound);
+	} else {
+		panic!("invalid event received");
+	}
+}
+
+#[tokio::test]
+async fn send_sync_notification() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (sink, _, mut sync_rx) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+
+	// report that a substream has been opened
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	if let Some(NotificationEvent::NotificationStreamOpened {
+		peer,
+		negotiated_fallback,
+		handshake,
+		direction,
+	}) = notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(negotiated_fallback, None);
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		assert_eq!(direction, Direction::Inbound);
+	} else {
+		panic!("invalid event received");
+	}
+
+	notif.send_sync_notification(&peer_id.into(), vec![1, 3, 3, 8]);
+	assert_eq!(
+		sync_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 8] })
+	);
+}
+
+#[tokio::test]
+async fn send_async_notification() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (sink, mut async_rx, _) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+
+	// report that a substream has been opened
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	if let Some(NotificationEvent::NotificationStreamOpened {
+		peer,
+		negotiated_fallback,
+		handshake,
+		direction,
+	}) = notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(negotiated_fallback, None);
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		assert_eq!(direction, Direction::Inbound);
+	} else {
+		panic!("invalid event received");
+	}
+
+	notif.send_async_notification(&peer_id.into(), vec![1, 3, 3, 9]).await.unwrap();
+	assert_eq!(
+		async_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 9] })
+	);
+}
+
+#[tokio::test]
+async fn send_sync_notification_to_non_existent_peer() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (_sink, _, _sync_rx) = NotificationsSink::new(PeerId::random());
+	let (_handle, _stream) = proto.split();
+	let peer = PeerId::random();
+
+	// as per the original implementation, the call doesn't fail
+	notif.send_sync_notification(&peer.into(), vec![1, 3, 3, 7])
+}
+
+#[tokio::test]
+async fn send_async_notification_to_non_existent_peer() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (_sink, _, _sync_rx) = NotificationsSink::new(PeerId::random());
+	let (_handle, _stream) = proto.split();
+	let peer = PeerId::random();
+
+	if let Err(error::Error::PeerDoesntExist(peer_id)) =
+		notif.send_async_notification(&peer.into(), vec![1, 3, 3, 7]).await
+	{
+		assert_eq!(peer, peer_id.into());
+	} else {
+		panic!("invalid error received from `send_async_notification()`");
+	}
+}
+
+#[tokio::test]
+async fn receive_notification() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (sink, _, _sync_rx) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+
+	// report that a substream has been opened
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	if let Some(NotificationEvent::NotificationStreamOpened {
+		peer,
+		negotiated_fallback,
+		handshake,
+		direction,
+	}) = notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(negotiated_fallback, None);
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		assert_eq!(direction, Direction::Inbound);
+	} else {
+		panic!("invalid event received");
+	}
+
+	// notification is received
+	handle.report_notification_received(peer_id, vec![1, 3, 3, 8]).unwrap();
+
+	if let Some(NotificationEvent::NotificationReceived { peer, notification }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(notification, vec![1, 3, 3, 8]);
+	} else {
+		panic!("invalid event received");
+	}
+}
+
+#[tokio::test]
+async fn backpressure_works() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (sink, mut async_rx, _) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+
+	// report that a substream has been opened
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	if let Some(NotificationEvent::NotificationStreamOpened {
+		peer,
+		negotiated_fallback,
+		handshake,
+		direction,
+	}) = notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(negotiated_fallback, None);
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		assert_eq!(direction, Direction::Inbound);
+	} else {
+		panic!("invalid event received");
+	}
+
+	// fill the message buffer with messages
+	for i in 0..=ASYNC_NOTIFICATIONS_BUFFER_SIZE {
+		assert!(futures::poll!(
+			notif.send_async_notification(&peer_id.into(), vec![1, 3, 3, i as u8])
+		)
+		.is_ready());
+	}
+
+	// try to send one more message and verify that the call blocks
+	assert!(futures::poll!(notif.send_async_notification(&peer_id.into(), vec![1, 3, 3, 9]))
+		.is_pending());
+
+	// release one slot from the buffer for new message
+	assert_eq!(
+		async_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 0] })
+	);
+
+	// verify that a message can be sent
+	assert!(
+		futures::poll!(notif.send_async_notification(&peer_id.into(), vec![1, 3, 3, 9])).is_ready()
+	);
+}
+
+#[tokio::test]
+async fn peer_disconnects_then_sync_notification_is_sent() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (sink, _, sync_rx) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+
+	// report that a substream has been opened
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	if let Some(NotificationEvent::NotificationStreamOpened {
+		peer,
+		negotiated_fallback,
+		handshake,
+		direction,
+	}) = notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(negotiated_fallback, None);
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		assert_eq!(direction, Direction::Inbound);
+	} else {
+		panic!("invalid event received");
+	}
+
+	// report that a substream has been closed but don't poll `notif` to receive this
+	// information
+	handle.report_substream_closed(peer_id).unwrap();
+	drop(sync_rx);
+
+	// as per documentation, error is not reported but the notification is silently dropped
+	notif.send_sync_notification(&peer_id.into(), vec![1, 3, 3, 7]);
+}
+
+#[tokio::test]
+async fn peer_disconnects_then_async_notification_is_sent() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (sink, async_rx, _) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+
+	// report that a substream has been opened
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	if let Some(NotificationEvent::NotificationStreamOpened {
+		peer,
+		negotiated_fallback,
+		handshake,
+		direction,
+	}) = notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(negotiated_fallback, None);
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		assert_eq!(direction, Direction::Inbound);
+	} else {
+		panic!("invalid event received");
+	}
+
+	// report that a substream has been closed but don't poll `notif` to receive this
+	// information
+	handle.report_substream_closed(peer_id).unwrap();
+	drop(async_rx);
+
+	// as per documentation, error is not reported but the notification is silently dropped
+	if let Err(error::Error::ConnectionClosed) =
+		notif.send_async_notification(&peer_id.into(), vec![1, 3, 3, 7]).await
+	{
+	} else {
+		panic!("invalid state after calling `send_async_notification()` on closed connection")
+	}
+}
+
+#[tokio::test]
+async fn cloned_service_opening_substream_works() {
+	let (proto, mut notif1) = notification_service("/proto/1".into());
+	let (_sink, _async_rx, _) = NotificationsSink::new(PeerId::random());
+	let (handle, _stream) = proto.split();
+	let mut notif2 = notif1.clone().unwrap();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(mut result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	// verify that `notif1` gets the event
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif1.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+
+	// verify that because only one listener has thus far send their result, the result is
+	// pending
+	assert!(result_rx.try_recv().is_err());
+
+	// verify that `notif2` also gets the event
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif2.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+}
+
+#[tokio::test]
+async fn cloned_service_one_service_rejects_substream() {
+	let (proto, mut notif1) = notification_service("/proto/1".into());
+	let (_sink, _async_rx, _) = NotificationsSink::new(PeerId::random());
+	let (handle, _stream) = proto.split();
+	let mut notif2 = notif1.clone().unwrap();
+	let mut notif3 = notif2.clone().unwrap();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(mut result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	for notif in vec![&mut notif1, &mut notif2] {
+		if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+			notif.next_event().await
+		{
+			assert_eq!(peer_id, peer.into());
+			assert_eq!(handshake, vec![1, 3, 3, 7]);
+			let _ = result_tx.send(ValidationResult::Accept).unwrap();
+		} else {
+			panic!("invalid event received");
+		}
+	}
+
+	// `notif3` has not yet sent their validation result
+	assert!(result_rx.try_recv().is_err());
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif3.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Reject).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Reject);
+}
+
+#[tokio::test]
+async fn cloned_service_opening_substream_sending_and_receiving_notifications_work() {
+	let (proto, mut notif1) = notification_service("/proto/1".into());
+	let (sink, _, mut sync_rx) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+	let mut notif2 = notif1.clone().unwrap();
+	let mut notif3 = notif1.clone().unwrap();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	for notif in vec![&mut notif1, &mut notif2, &mut notif3] {
+		// accept the inbound substream for all services
+		if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+			notif.next_event().await
+		{
+			assert_eq!(peer_id, peer.into());
+			assert_eq!(handshake, vec![1, 3, 3, 7]);
+			let _ = result_tx.send(ValidationResult::Accept).unwrap();
+		} else {
+			panic!("invalid event received");
+		}
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+
+	// report that then notification stream has been opened
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	for notif in vec![&mut notif1, &mut notif2, &mut notif3] {
+		if let Some(NotificationEvent::NotificationStreamOpened {
+			peer,
+			negotiated_fallback,
+			handshake,
+			direction,
+		}) = notif.next_event().await
+		{
+			assert_eq!(peer_id, peer.into());
+			assert_eq!(negotiated_fallback, None);
+			assert_eq!(handshake, vec![1, 3, 3, 7]);
+			assert_eq!(direction, Direction::Inbound);
+		} else {
+			panic!("invalid event received");
+		}
+	}
+	// receive a notification from peer and verify all services receive it
+	handle.report_notification_received(peer_id, vec![1, 3, 3, 8]).unwrap();
+
+	for notif in vec![&mut notif1, &mut notif2, &mut notif3] {
+		if let Some(NotificationEvent::NotificationReceived { peer, notification }) =
+			notif.next_event().await
+		{
+			assert_eq!(peer_id, peer.into());
+			assert_eq!(notification, vec![1, 3, 3, 8]);
+		} else {
+			panic!("invalid event received");
+		}
+	}
+
+	for (i, notif) in vec![&mut notif1, &mut notif2, &mut notif3].iter_mut().enumerate() {
+		// send notification from each service and verify peer receives it
+		notif.send_sync_notification(&peer_id.into(), vec![1, 3, 3, i as u8]);
+		assert_eq!(
+			sync_rx.next().await,
+			Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, i as u8] })
+		);
+	}
+
+	// close the substream for peer and verify all services receive the event
+	handle.report_substream_closed(peer_id).unwrap();
+
+	for notif in vec![&mut notif1, &mut notif2, &mut notif3] {
+		if let Some(NotificationEvent::NotificationStreamClosed { peer }) = notif.next_event().await
+		{
+			assert_eq!(peer_id, peer.into());
+		} else {
+			panic!("invalid event received");
+		}
+	}
+}
+
+#[tokio::test]
+async fn sending_notifications_using_notifications_sink_works() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (sink, mut async_rx, mut sync_rx) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+
+	// report that a substream has been opened
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	if let Some(NotificationEvent::NotificationStreamOpened {
+		peer,
+		negotiated_fallback,
+		handshake,
+		direction,
+	}) = notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(negotiated_fallback, None);
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		assert_eq!(direction, Direction::Inbound);
+	} else {
+		panic!("invalid event received");
+	}
+
+	// get a copy of the notification sink and send a synchronous notification using.
+	let sink = notif.message_sink(&peer_id.into()).unwrap();
+	sink.send_sync_notification(vec![1, 3, 3, 6]);
+
+	// send an asynchronous notification using the acquired notifications sink.
+	let _ = sink.send_async_notification(vec![1, 3, 3, 7]).await.unwrap();
+
+	assert_eq!(
+		sync_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 6] }),
+	);
+	assert_eq!(
+		async_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 7] }),
+	);
+
+	// send notifications using the stored notification sink as well.
+	notif.send_sync_notification(&peer_id.into(), vec![1, 3, 3, 8]);
+	notif.send_async_notification(&peer_id.into(), vec![1, 3, 3, 9]).await.unwrap();
+
+	assert_eq!(
+		sync_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 8] }),
+	);
+	assert_eq!(
+		async_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 9] }),
+	);
+}
+
+#[test]
+fn try_to_get_notifications_sink_for_non_existent_peer() {
+	let (_proto, notif) = notification_service("/proto/1".into());
+	assert!(notif.message_sink(&pezsc_network_types::PeerId::random()).is_none());
+}
+
+#[tokio::test]
+async fn notification_sink_replaced() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (sink, mut async_rx, mut sync_rx) = NotificationsSink::new(PeerId::random());
+	let (mut handle, _stream) = proto.split();
+	let peer_id = PeerId::random();
+
+	// validate inbound substream
+	let ValidationCallResult::WaitForValidation(result_rx) =
+		handle.report_incoming_substream(peer_id, vec![1, 3, 3, 7]).unwrap()
+	else {
+		panic!("peerset not enabled");
+	};
+
+	if let Some(NotificationEvent::ValidateInboundSubstream { peer, handshake, result_tx }) =
+		notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		let _ = result_tx.send(ValidationResult::Accept).unwrap();
+	} else {
+		panic!("invalid event received");
+	}
+	assert_eq!(result_rx.await.unwrap(), ValidationResult::Accept);
+
+	// report that a substream has been opened
+	handle
+		.report_substream_opened(peer_id, Direction::Inbound, vec![1, 3, 3, 7], None, sink)
+		.unwrap();
+
+	if let Some(NotificationEvent::NotificationStreamOpened {
+		peer,
+		negotiated_fallback,
+		handshake,
+		direction,
+	}) = notif.next_event().await
+	{
+		assert_eq!(peer_id, peer.into());
+		assert_eq!(negotiated_fallback, None);
+		assert_eq!(handshake, vec![1, 3, 3, 7]);
+		assert_eq!(direction, Direction::Inbound);
+	} else {
+		panic!("invalid event received");
+	}
+
+	// get a copy of the notification sink and send a synchronous notification using.
+	let sink = notif.message_sink(&peer_id.into()).unwrap();
+	sink.send_sync_notification(vec![1, 3, 3, 6]);
+
+	// send an asynchronous notification using the acquired notifications sink.
+	let _ = sink.send_async_notification(vec![1, 3, 3, 7]).await.unwrap();
+
+	assert_eq!(
+		sync_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 6] }),
+	);
+	assert_eq!(
+		async_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 7] }),
+	);
+
+	// send notifications using the stored notification sink as well.
+	notif.send_sync_notification(&peer_id.into(), vec![1, 3, 3, 8]);
+	notif.send_async_notification(&peer_id.into(), vec![1, 3, 3, 9]).await.unwrap();
+
+	assert_eq!(
+		sync_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 8] }),
+	);
+	assert_eq!(
+		async_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 9] }),
+	);
+
+	// the initial connection was closed and `Notifications` switched to secondary connection
+	// and emitted `CustomProtocolReplaced` which informs the local `NotificationService` that
+	// the notification sink was replaced.
+	let (new_sink, mut new_async_rx, mut new_sync_rx) = NotificationsSink::new(PeerId::random());
+	handle.report_notification_sink_replaced(peer_id, new_sink).unwrap();
+
+	// drop the old sinks and poll `notif` once to register the sink replacement
+	drop(sync_rx);
+	drop(async_rx);
+
+	futures::future::poll_fn(|cx| {
+		let _ = std::pin::Pin::new(&mut notif.next_event()).poll(cx);
+		std::task::Poll::Ready(())
+	})
+	.await;
+
+	// verify that using the `NotificationService` API automatically results in using the correct
+	// sink
+	notif.send_sync_notification(&peer_id.into(), vec![1, 3, 3, 8]);
+	notif.send_async_notification(&peer_id.into(), vec![1, 3, 3, 9]).await.unwrap();
+
+	assert_eq!(
+		new_sync_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 8] }),
+	);
+	assert_eq!(
+		new_async_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 9] }),
+	);
+
+	// now send two notifications using the acquired message sink and verify that
+	// it's also updated
+	sink.send_sync_notification(vec![1, 3, 3, 6]);
+
+	// send an asynchronous notification using the acquired notifications sink.
+	let _ = sink.send_async_notification(vec![1, 3, 3, 7]).await.unwrap();
+
+	assert_eq!(
+		new_sync_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 6] }),
+	);
+	assert_eq!(
+		new_async_rx.next().await,
+		Some(NotificationsSinkMessage::Notification { message: vec![1, 3, 3, 7] }),
+	);
+}
+
+#[tokio::test]
+async fn set_handshake() {
+	let (proto, mut notif) = notification_service("/proto/1".into());
+	let (_handle, mut stream) = proto.split();
+
+	assert!(notif.try_set_handshake(vec![1, 3, 3, 7]).is_ok());
+
+	match stream.next().await {
+		Some(NotificationCommand::SetHandshake(handshake)) => {
+			assert_eq!(handshake, vec![1, 3, 3, 7]);
+		},
+		_ => panic!("invalid event received"),
+	}
+
+	for _ in 0..COMMAND_QUEUE_SIZE {
+		assert!(notif.try_set_handshake(vec![1, 3, 3, 7]).is_ok());
+	}
+
+	assert!(notif.try_set_handshake(vec![1, 3, 3, 7]).is_err());
+}

bizinikiwi/client/network/src/protocol/notifications/tests/mod.rs

@@ -0,0 +1,392 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+#![cfg(test)]
+
+use crate::{
+	peer_store::PeerStore,
+	protocol::notifications::{Notifications, NotificationsOut, ProtocolConfig},
+	protocol_controller::{ProtoSetConfig, ProtocolController, SetId},
+	service::{
+		metrics::NotificationMetrics,
+		traits::{NotificationEvent, ValidationResult},
+	},
+};
+
+use futures::{future::BoxFuture, prelude::*};
+use libp2p::{
+	core::{
+		transport::{MemoryTransport, PortUse},
+		upgrade, Endpoint,
+	},
+	identity, noise,
+	swarm::{
+		behaviour::FromSwarm, ConnectionDenied, ConnectionId, NetworkBehaviour, Swarm, SwarmEvent,
+		THandler, THandlerInEvent, THandlerOutEvent, ToSwarm,
+	},
+	yamux, Multiaddr, PeerId, SwarmBuilder, Transport,
+};
+use pezsc_utils::mpsc::tracing_unbounded;
+use std::{
+	iter,
+	sync::Arc,
+	task::{Context, Poll},
+	time::Duration,
+};
+
+#[cfg(test)]
+mod conformance;
+
+/// Builds two nodes that have each other as bootstrap nodes.
+/// This is to be used only for testing, and a panic will happen if something goes wrong.
+fn build_nodes() -> (Swarm<CustomProtoWithAddr>, Swarm<CustomProtoWithAddr>) {
+	let mut out = Vec::with_capacity(2);
+
+	let keypairs: Vec<_> = (0..2).map(|_| identity::Keypair::generate_ed25519()).collect();
+	let addrs: Vec<Multiaddr> = (0..2)
+		.map(|_| format!("/memory/{}", rand::random::<u64>()).parse().unwrap())
+		.collect();
+
+	for index in 0..2 {
+		let keypair = keypairs[index].clone();
+
+		let (protocol_handle_pair, mut notif_service) =
+			crate::protocol::notifications::service::notification_service("/foo".into());
+		// The first swarm has the second peer ID present in the peerstore.
+		let peer_store = PeerStore::new(
+			if index == 0 {
+				keypairs.iter().skip(1).map(|keypair| keypair.public().to_peer_id()).collect()
+			} else {
+				vec![]
+			},
+			None,
+		);
+
+		let (to_notifications, from_controller) =
+			tracing_unbounded("test_protocol_controller_to_notifications", 10_000);
+
+		let (controller_handle, controller) = ProtocolController::new(
+			SetId::from(0),
+			ProtoSetConfig {
+				in_peers: 25,
+				out_peers: 25,
+				reserved_nodes: Default::default(),
+				reserved_only: false,
+			},
+			to_notifications,
+			Arc::new(peer_store.handle()),
+		);
+
+		let (notif_handle, command_stream) = protocol_handle_pair.split();
+
+		tokio::spawn(async move {
+			loop {
+				if let NotificationEvent::ValidateInboundSubstream { result_tx, .. } =
+					notif_service.next_event().await.unwrap()
+				{
+					result_tx.send(ValidationResult::Accept).unwrap();
+				}
+			}
+		});
+
+		let mut swarm = SwarmBuilder::with_existing_identity(keypair)
+			.with_tokio()
+			.with_other_transport(|keypair| {
+				MemoryTransport::new()
+					.upgrade(upgrade::Version::V1)
+					.authenticate(noise::Config::new(&keypair).unwrap())
+					.multiplex(yamux::Config::default())
+					.timeout(Duration::from_secs(20))
+					.boxed()
+			})
+			.unwrap()
+			.with_behaviour(|_keypair| CustomProtoWithAddr {
+				inner: Notifications::new(
+					vec![controller_handle],
+					from_controller,
+					NotificationMetrics::new(None),
+					iter::once((
+						ProtocolConfig {
+							name: "/foo".into(),
+							fallback_names: Vec::new(),
+							handshake: Vec::new(),
+							max_notification_size: 1024 * 1024,
+						},
+						notif_handle,
+						command_stream,
+					)),
+				),
+				peer_store_future: peer_store.run().boxed(),
+				protocol_controller_future: controller.run().boxed(),
+				addrs: addrs
+					.iter()
+					.enumerate()
+					.filter_map(|(n, a)| {
+						if n != index {
+							Some((keypairs[n].public().to_peer_id(), a.clone()))
+						} else {
+							None
+						}
+					})
+					.collect(),
+			})
+			.unwrap()
+			.build();
+		swarm.listen_on(addrs[index].clone()).unwrap();
+		out.push(swarm);
+	}
+
+	// Final output
+	let mut out_iter = out.into_iter();
+	let first = out_iter.next().unwrap();
+	let second = out_iter.next().unwrap();
+	(first, second)
+}
+
+/// Wraps around the `CustomBehaviour` network behaviour, and adds hardcoded node addresses to it.
+struct CustomProtoWithAddr {
+	inner: Notifications,
+	peer_store_future: BoxFuture<'static, ()>,
+	protocol_controller_future: BoxFuture<'static, ()>,
+	addrs: Vec<(PeerId, Multiaddr)>,
+}
+
+impl std::ops::Deref for CustomProtoWithAddr {
+	type Target = Notifications;
+
+	fn deref(&self) -> &Self::Target {
+		&self.inner
+	}
+}
+
+impl std::ops::DerefMut for CustomProtoWithAddr {
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		&mut self.inner
+	}
+}
+
+impl NetworkBehaviour for CustomProtoWithAddr {
+	type ConnectionHandler = <Notifications as NetworkBehaviour>::ConnectionHandler;
+	type ToSwarm = <Notifications as NetworkBehaviour>::ToSwarm;
+
+	fn handle_pending_inbound_connection(
+		&mut self,
+		connection_id: ConnectionId,
+		local_addr: &Multiaddr,
+		remote_addr: &Multiaddr,
+	) -> Result<(), ConnectionDenied> {
+		self.inner
+			.handle_pending_inbound_connection(connection_id, local_addr, remote_addr)
+	}
+
+	fn handle_pending_outbound_connection(
+		&mut self,
+		connection_id: ConnectionId,
+		maybe_peer: Option<PeerId>,
+		addresses: &[Multiaddr],
+		effective_role: Endpoint,
+	) -> Result<Vec<Multiaddr>, ConnectionDenied> {
+		let mut list = self.inner.handle_pending_outbound_connection(
+			connection_id,
+			maybe_peer,
+			addresses,
+			effective_role,
+		)?;
+		if let Some(peer_id) = maybe_peer {
+			for (p, a) in self.addrs.iter() {
+				if *p == peer_id {
+					list.push(a.clone());
+				}
+			}
+		}
+		Ok(list)
+	}
+
+	fn handle_established_inbound_connection(
+		&mut self,
+		connection_id: ConnectionId,
+		peer: PeerId,
+		local_addr: &Multiaddr,
+		remote_addr: &Multiaddr,
+	) -> Result<THandler<Self>, ConnectionDenied> {
+		self.inner.handle_established_inbound_connection(
+			connection_id,
+			peer,
+			local_addr,
+			remote_addr,
+		)
+	}
+
+	fn handle_established_outbound_connection(
+		&mut self,
+		connection_id: ConnectionId,
+		peer: PeerId,
+		addr: &Multiaddr,
+		role_override: Endpoint,
+		port_use: PortUse,
+	) -> Result<THandler<Self>, ConnectionDenied> {
+		self.inner.handle_established_outbound_connection(
+			connection_id,
+			peer,
+			addr,
+			role_override,
+			port_use,
+		)
+	}
+
+	fn on_swarm_event(&mut self, event: FromSwarm) {
+		self.inner.on_swarm_event(event);
+	}
+
+	fn on_connection_handler_event(
+		&mut self,
+		peer_id: PeerId,
+		connection_id: ConnectionId,
+		event: THandlerOutEvent<Self>,
+	) {
+		self.inner.on_connection_handler_event(peer_id, connection_id, event);
+	}
+
+	fn poll(&mut self, cx: &mut Context) -> Poll<ToSwarm<Self::ToSwarm, THandlerInEvent<Self>>> {
+		let _ = self.peer_store_future.poll_unpin(cx);
+		let _ = self.protocol_controller_future.poll_unpin(cx);
+		self.inner.poll(cx)
+	}
+}
+
+#[tokio::test]
+async fn reconnect_after_disconnect() {
+	// We connect two nodes together, then force a disconnect (through the API of the `Service`),
+	// check that the disconnect worked, and finally check whether they successfully reconnect.
+
+	let (mut service1, mut service2) = build_nodes();
+
+	// For this test, the services can be in the following states.
+	#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+	enum ServiceState {
+		NotConnected,
+		FirstConnec,
+		Disconnected,
+		ConnectedAgain,
+	}
+	let mut service1_state = ServiceState::NotConnected;
+	let mut service2_state = ServiceState::NotConnected;
+
+	loop {
+		// Grab next event from services.
+		let event = {
+			let s1 = service1.select_next_some();
+			let s2 = service2.select_next_some();
+			futures::pin_mut!(s1, s2);
+			match future::select(s1, s2).await {
+				future::Either::Left((ev, _)) => future::Either::Left(ev),
+				future::Either::Right((ev, _)) => future::Either::Right(ev),
+			}
+		};
+
+		match event {
+			future::Either::Left(SwarmEvent::Behaviour(NotificationsOut::CustomProtocolOpen {
+				..
+			})) => match service1_state {
+				ServiceState::NotConnected => {
+					service1_state = ServiceState::FirstConnec;
+					if service2_state == ServiceState::FirstConnec {
+						service1
+							.behaviour_mut()
+							.disconnect_peer(Swarm::local_peer_id(&service2), SetId::from(0));
+					}
+				},
+				ServiceState::Disconnected => service1_state = ServiceState::ConnectedAgain,
+				ServiceState::FirstConnec | ServiceState::ConnectedAgain => panic!(),
+			},
+			future::Either::Left(SwarmEvent::Behaviour(
+				NotificationsOut::CustomProtocolClosed { .. },
+			)) => match service1_state {
+				ServiceState::FirstConnec => service1_state = ServiceState::Disconnected,
+				ServiceState::ConnectedAgain |
+				ServiceState::NotConnected |
+				ServiceState::Disconnected => panic!(),
+			},
+			future::Either::Right(SwarmEvent::Behaviour(
+				NotificationsOut::CustomProtocolOpen { .. },
+			)) => match service2_state {
+				ServiceState::NotConnected => {
+					service2_state = ServiceState::FirstConnec;
+					if service1_state == ServiceState::FirstConnec {
+						service1
+							.behaviour_mut()
+							.disconnect_peer(Swarm::local_peer_id(&service2), SetId::from(0));
+					}
+				},
+				ServiceState::Disconnected => service2_state = ServiceState::ConnectedAgain,
+				ServiceState::FirstConnec | ServiceState::ConnectedAgain => panic!(),
+			},
+			future::Either::Right(SwarmEvent::Behaviour(
+				NotificationsOut::CustomProtocolClosed { .. },
+			)) => match service2_state {
+				ServiceState::FirstConnec => service2_state = ServiceState::Disconnected,
+				ServiceState::ConnectedAgain |
+				ServiceState::NotConnected |
+				ServiceState::Disconnected => panic!(),
+			},
+			_ => {},
+		}
+
+		// Due to the bug in `Notifications`, the disconnected node does not always detect that
+		// it was disconnected. The closed inbound substream is tolerated by design, and the
+		// closed outbound substream is not detected until something is sent into it.
+		// See [PR #13396](https://github.com/pezkuwichain/kurdistan-sdk/issues/45).
+		// This happens if the disconnecting node reconnects to it fast enough.
+		// In this case the disconnected node does not transit via `ServiceState::NotConnected`
+		// and stays in `ServiceState::FirstConnec`.
+		// TODO: update this once the fix is finally merged.
+		if service1_state == ServiceState::ConnectedAgain &&
+			service2_state == ServiceState::ConnectedAgain ||
+			service1_state == ServiceState::ConnectedAgain &&
+				service2_state == ServiceState::FirstConnec ||
+			service1_state == ServiceState::FirstConnec &&
+				service2_state == ServiceState::ConnectedAgain
+		{
+			break;
+		}
+	}
+
+	// Now that the two services have disconnected and reconnected, wait for 3 seconds and
+	// check whether they're still connected.
+	let mut delay = futures_timer::Delay::new(Duration::from_secs(3));
+
+	loop {
+		// Grab next event from services.
+		let event = {
+			let s1 = service1.select_next_some();
+			let s2 = service2.select_next_some();
+			futures::pin_mut!(s1, s2);
+			match future::select(future::select(s1, s2), &mut delay).await {
+				future::Either::Right(_) => break, // success
+				future::Either::Left((future::Either::Left((ev, _)), _)) => ev,
+				future::Either::Left((future::Either::Right((ev, _)), _)) => ev,
+			}
+		};
+
+		match event {
+			SwarmEvent::Behaviour(NotificationsOut::CustomProtocolOpen { .. }) |
+			SwarmEvent::Behaviour(NotificationsOut::CustomProtocolClosed { .. }) => panic!(),
+			_ => {},
+		}
+	}
+}

bizinikiwi/client/network/src/protocol/notifications/upgrade.rs

@@ -0,0 +1,34 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+#[cfg(test)]
+pub(crate) use self::notifications::{
+	NotificationsInOpen, NotificationsInSubstreamHandshake, NotificationsOutOpen,
+};
+
+pub(crate) use notifications::NotificationsOutError;
+
+pub use self::{
+	collec::UpgradeCollec,
+	notifications::{
+		NotificationsIn, NotificationsInSubstream, NotificationsOut, NotificationsOutSubstream,
+	},
+};
+
+mod collec;
+mod notifications;

bizinikiwi/client/network/src/protocol/notifications/upgrade/collec.rs

@@ -0,0 +1,178 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use futures::prelude::*;
+use libp2p::core::upgrade::{InboundUpgrade, UpgradeInfo};
+use std::{
+	pin::Pin,
+	task::{Context, Poll},
+	vec,
+};
+
+// TODO: move this to libp2p => https://github.com/libp2p/rust-libp2p/issues/1445
+
+/// Upgrade that combines multiple upgrades of the same type into one. Supports all the protocols
+/// supported by either sub-upgrade.
+#[derive(Debug, Clone)]
+pub struct UpgradeCollec<T>(pub Vec<T>);
+
+impl<T> From<Vec<T>> for UpgradeCollec<T> {
+	fn from(list: Vec<T>) -> Self {
+		Self(list)
+	}
+}
+
+impl<T> FromIterator<T> for UpgradeCollec<T> {
+	fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
+		Self(iter.into_iter().collect())
+	}
+}
+
+impl<T: UpgradeInfo> UpgradeInfo for UpgradeCollec<T> {
+	type Info = ProtoNameWithUsize<T::Info>;
+	type InfoIter = vec::IntoIter<Self::Info>;
+
+	fn protocol_info(&self) -> Self::InfoIter {
+		self.0
+			.iter()
+			.enumerate()
+			.flat_map(|(n, p)| p.protocol_info().into_iter().map(move |i| ProtoNameWithUsize(i, n)))
+			.collect::<Vec<_>>()
+			.into_iter()
+	}
+}
+
+impl<T, C> InboundUpgrade<C> for UpgradeCollec<T>
+where
+	T: InboundUpgrade<C>,
+{
+	type Output = (T::Output, usize);
+	type Error = (T::Error, usize);
+	type Future = FutWithUsize<T::Future>;
+
+	fn upgrade_inbound(mut self, sock: C, info: Self::Info) -> Self::Future {
+		let fut = self.0.remove(info.1).upgrade_inbound(sock, info.0);
+		FutWithUsize(fut, info.1)
+	}
+}
+
+/// Groups a `ProtocolName` with a `usize`.
+#[derive(Debug, Clone, PartialEq)]
+pub struct ProtoNameWithUsize<T>(T, usize);
+
+impl<T: AsRef<str>> AsRef<str> for ProtoNameWithUsize<T> {
+	fn as_ref(&self) -> &str {
+		self.0.as_ref()
+	}
+}
+
+/// Equivalent to `fut.map_ok(|v| (v, num)).map_err(|e| (e, num))`, where `fut` and `num` are
+/// the two fields of this struct.
+#[pin_project::pin_project]
+pub struct FutWithUsize<T>(#[pin] T, usize);
+
+impl<T: Future<Output = Result<O, E>>, O, E> Future for FutWithUsize<T> {
+	type Output = Result<(O, usize), (E, usize)>;
+
+	fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+		let this = self.project();
+		match Future::poll(this.0, cx) {
+			Poll::Ready(Ok(v)) => Poll::Ready(Ok((v, *this.1))),
+			Poll::Ready(Err(e)) => Poll::Ready(Err((e, *this.1))),
+			Poll::Pending => Poll::Pending,
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::types::ProtocolName as ProtoName;
+	use libp2p::core::upgrade::UpgradeInfo;
+
+	// TODO: move to mocks
+	mockall::mock! {
+		pub ProtocolUpgrade<T> {}
+
+		impl<T: Clone + AsRef<str>> UpgradeInfo for ProtocolUpgrade<T> {
+			type Info = T;
+			type InfoIter = vec::IntoIter<T>;
+			fn protocol_info(&self) -> vec::IntoIter<T>;
+		}
+	}
+
+	#[test]
+	fn protocol_info() {
+		let upgrades = (1..=3)
+			.map(|i| {
+				let mut upgrade = MockProtocolUpgrade::<ProtoNameWithUsize<ProtoName>>::new();
+				upgrade.expect_protocol_info().return_once(move || {
+					vec![ProtoNameWithUsize(ProtoName::from(format!("protocol{i}")), i)].into_iter()
+				});
+				upgrade
+			})
+			.collect::<Vec<_>>();
+
+		let upgrade: UpgradeCollec<_> = upgrades.into_iter().collect::<UpgradeCollec<_>>();
+		let protos = vec![
+			ProtoNameWithUsize(ProtoNameWithUsize(ProtoName::from("protocol1".to_string()), 1), 0),
+			ProtoNameWithUsize(ProtoNameWithUsize(ProtoName::from("protocol2".to_string()), 2), 1),
+			ProtoNameWithUsize(ProtoNameWithUsize(ProtoName::from("protocol3".to_string()), 3), 2),
+		];
+		let upgrades = upgrade.protocol_info().collect::<Vec<_>>();
+
+		assert_eq!(upgrades, protos,);
+	}
+
+	#[test]
+	fn nested_protocol_info() {
+		let mut upgrades = (1..=2)
+			.map(|i| {
+				let mut upgrade = MockProtocolUpgrade::<ProtoNameWithUsize<ProtoName>>::new();
+				upgrade.expect_protocol_info().return_once(move || {
+					vec![ProtoNameWithUsize(ProtoName::from(format!("protocol{i}")), i)].into_iter()
+				});
+				upgrade
+			})
+			.collect::<Vec<_>>();
+
+		upgrades.push({
+			let mut upgrade = MockProtocolUpgrade::<ProtoNameWithUsize<ProtoName>>::new();
+			upgrade.expect_protocol_info().return_once(move || {
+				vec![
+					ProtoNameWithUsize(ProtoName::from("protocol22".to_string()), 1),
+					ProtoNameWithUsize(ProtoName::from("protocol33".to_string()), 2),
+					ProtoNameWithUsize(ProtoName::from("protocol44".to_string()), 3),
+				]
+				.into_iter()
+			});
+			upgrade
+		});
+
+		let upgrade: UpgradeCollec<_> = upgrades.into_iter().collect::<UpgradeCollec<_>>();
+		let protos = vec![
+			ProtoNameWithUsize(ProtoNameWithUsize(ProtoName::from("protocol1".to_string()), 1), 0),
+			ProtoNameWithUsize(ProtoNameWithUsize(ProtoName::from("protocol2".to_string()), 2), 1),
+			ProtoNameWithUsize(ProtoNameWithUsize(ProtoName::from("protocol22".to_string()), 1), 2),
+			ProtoNameWithUsize(ProtoNameWithUsize(ProtoName::from("protocol33".to_string()), 2), 2),
+			ProtoNameWithUsize(ProtoNameWithUsize(ProtoName::from("protocol44".to_string()), 3), 2),
+		];
+		let upgrades = upgrade.protocol_info().collect::<Vec<_>>();
+		assert_eq!(upgrades, protos,);
+	}
+}

bizinikiwi/client/network/src/protocol/notifications/upgrade/notifications.rs

@@ -0,0 +1,865 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+/// Notifications protocol.
+///
+/// The Bizinikiwi notifications protocol consists in the following:
+///
+/// - Node A opens a substream to node B and sends a message which contains some
+///   protocol-specific higher-level logic. This message is prefixed with a variable-length
+///   integer message length. This message can be empty, in which case `0` is sent.
+/// - If node B accepts the substream, it sends back a message with the same properties.
+/// - If instead B refuses the connection (which typically happens because no empty slot is
+///   available), then it immediately closes the substream without sending back anything.
+/// - Node A can then send notifications to B, prefixed with a variable-length integer
+///   indicating the length of the message.
+/// - Either node A or node B can signal that it doesn't want this notifications substream
+///   anymore by closing its writing side. The other party should respond by also closing their
+///   own writing side soon after.
+///
+/// Notification substreams are unidirectional. If A opens a substream with B, then B is
+/// encouraged but not required to open a substream to A as well.
+use crate::types::ProtocolName;
+
+use asynchronous_codec::Framed;
+use bytes::BytesMut;
+use futures::prelude::*;
+use libp2p::{
+	core::{InboundUpgrade, OutboundUpgrade, UpgradeInfo},
+	PeerId,
+};
+use log::{debug, error, warn};
+use unsigned_varint::codec::UviBytes;
+
+use std::{
+	fmt, io, mem,
+	pin::Pin,
+	task::{Context, Poll},
+	vec,
+};
+
+/// Logging target for the file.
+const LOG_TARGET: &str = "sub-libp2p::notification::upgrade";
+
+/// Maximum allowed size of the two handshake messages, in bytes.
+const MAX_HANDSHAKE_SIZE: usize = 1024;
+
+/// Upgrade that accepts a substream, sends back a status message, then becomes a unidirectional
+/// stream of messages.
+#[derive(Debug, Clone)]
+pub struct NotificationsIn {
+	/// Protocol name to use when negotiating the substream.
+	/// The first one is the main name, while the other ones are fall backs.
+	protocol_names: Vec<ProtocolName>,
+	/// Maximum allowed size for a single notification.
+	max_notification_size: u64,
+}
+
+/// Upgrade that opens a substream, waits for the remote to accept by sending back a status
+/// message, then becomes a unidirectional sink of data.
+#[derive(Debug, Clone)]
+pub struct NotificationsOut {
+	/// Protocol name to use when negotiating the substream.
+	/// The first one is the main name, while the other ones are fall backs.
+	protocol_names: Vec<ProtocolName>,
+	/// Message to send when we start the handshake.
+	initial_message: Vec<u8>,
+	/// Maximum allowed size for a single notification.
+	max_notification_size: u64,
+	/// The peerID of the remote.
+	peer_id: PeerId,
+}
+
+/// A substream for incoming notification messages.
+///
+/// When creating, this struct starts in a state in which we must first send back a handshake
+/// message to the remote. No message will come before this has been done.
+#[pin_project::pin_project]
+pub struct NotificationsInSubstream<TSubstream> {
+	#[pin]
+	socket: Framed<TSubstream, UviBytes<io::Cursor<Vec<u8>>>>,
+	handshake: NotificationsInSubstreamHandshake,
+}
+
+/// State of the handshake sending back process.
+#[derive(Debug)]
+pub enum NotificationsInSubstreamHandshake {
+	/// Waiting for the user to give us the handshake message.
+	NotSent,
+	/// User gave us the handshake message. Trying to push it in the socket.
+	PendingSend(Vec<u8>),
+	/// Handshake message was pushed in the socket. Still need to flush.
+	Flush,
+	/// Handshake message successfully sent and flushed.
+	Sent,
+	/// Remote has closed their writing side. We close our own writing side in return.
+	ClosingInResponseToRemote,
+	/// Both our side and the remote have closed their writing side.
+	BothSidesClosed,
+}
+
+/// A substream for outgoing notification messages.
+#[pin_project::pin_project]
+pub struct NotificationsOutSubstream<TSubstream> {
+	/// Substream where to send messages.
+	#[pin]
+	socket: Framed<TSubstream, UviBytes<io::Cursor<Vec<u8>>>>,
+
+	/// The remote peer.
+	peer_id: PeerId,
+}
+
+#[cfg(test)]
+impl<TSubstream> NotificationsOutSubstream<TSubstream> {
+	pub fn new(socket: Framed<TSubstream, UviBytes<io::Cursor<Vec<u8>>>>) -> Self {
+		Self { socket, peer_id: PeerId::random() }
+	}
+}
+
+impl NotificationsIn {
+	/// Builds a new potential upgrade.
+	pub fn new(
+		main_protocol_name: impl Into<ProtocolName>,
+		fallback_names: Vec<ProtocolName>,
+		max_notification_size: u64,
+	) -> Self {
+		let mut protocol_names = fallback_names;
+		protocol_names.insert(0, main_protocol_name.into());
+
+		Self { protocol_names, max_notification_size }
+	}
+}
+
+impl UpgradeInfo for NotificationsIn {
+	type Info = ProtocolName;
+	type InfoIter = vec::IntoIter<Self::Info>;
+
+	fn protocol_info(&self) -> Self::InfoIter {
+		self.protocol_names.clone().into_iter()
+	}
+}
+
+impl<TSubstream> InboundUpgrade<TSubstream> for NotificationsIn
+where
+	TSubstream: AsyncRead + AsyncWrite + Unpin + Send + 'static,
+{
+	type Output = NotificationsInOpen<TSubstream>;
+	type Future = Pin<Box<dyn Future<Output = Result<Self::Output, Self::Error>> + Send>>;
+	type Error = NotificationsHandshakeError;
+
+	fn upgrade_inbound(self, mut socket: TSubstream, _negotiated_name: Self::Info) -> Self::Future {
+		Box::pin(async move {
+			let handshake_len = unsigned_varint::aio::read_usize(&mut socket).await?;
+			if handshake_len > MAX_HANDSHAKE_SIZE {
+				return Err(NotificationsHandshakeError::TooLarge {
+					requested: handshake_len,
+					max: MAX_HANDSHAKE_SIZE,
+				});
+			}
+
+			let mut handshake = vec![0u8; handshake_len];
+			if !handshake.is_empty() {
+				socket.read_exact(&mut handshake).await?;
+			}
+
+			let mut codec = UviBytes::default();
+			codec.set_max_len(usize::try_from(self.max_notification_size).unwrap_or(usize::MAX));
+
+			let substream = NotificationsInSubstream {
+				socket: Framed::new(socket, codec),
+				handshake: NotificationsInSubstreamHandshake::NotSent,
+			};
+
+			Ok(NotificationsInOpen { handshake, substream })
+		})
+	}
+}
+
+/// Yielded by the [`NotificationsIn`] after a successfully upgrade.
+pub struct NotificationsInOpen<TSubstream> {
+	/// Handshake sent by the remote.
+	pub handshake: Vec<u8>,
+	/// Implementation of `Stream` that allows receives messages from the substream.
+	pub substream: NotificationsInSubstream<TSubstream>,
+}
+
+impl<TSubstream> fmt::Debug for NotificationsInOpen<TSubstream> {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		f.debug_struct("NotificationsInOpen")
+			.field("handshake", &self.handshake)
+			.finish_non_exhaustive()
+	}
+}
+
+impl<TSubstream> NotificationsInSubstream<TSubstream>
+where
+	TSubstream: AsyncRead + AsyncWrite + Unpin,
+{
+	#[cfg(test)]
+	pub fn new(
+		socket: Framed<TSubstream, UviBytes<io::Cursor<Vec<u8>>>>,
+		handshake: NotificationsInSubstreamHandshake,
+	) -> Self {
+		Self { socket, handshake }
+	}
+
+	/// Sends the handshake in order to inform the remote that we accept the substream.
+	pub fn send_handshake(&mut self, message: impl Into<Vec<u8>>) {
+		if !matches!(self.handshake, NotificationsInSubstreamHandshake::NotSent) {
+			error!(target: LOG_TARGET, "Tried to send handshake twice");
+			return;
+		}
+
+		self.handshake = NotificationsInSubstreamHandshake::PendingSend(message.into());
+	}
+
+	/// Equivalent to `Stream::poll_next`, except that it only drives the handshake and is
+	/// guaranteed to not generate any notification.
+	pub fn poll_process(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), io::Error>> {
+		let mut this = self.project();
+
+		loop {
+			match mem::replace(this.handshake, NotificationsInSubstreamHandshake::Sent) {
+				NotificationsInSubstreamHandshake::PendingSend(msg) => {
+					match Sink::poll_ready(this.socket.as_mut(), cx) {
+						Poll::Ready(_) => {
+							*this.handshake = NotificationsInSubstreamHandshake::Flush;
+							match Sink::start_send(this.socket.as_mut(), io::Cursor::new(msg)) {
+								Ok(()) => {},
+								Err(err) => return Poll::Ready(Err(err)),
+							}
+						},
+						Poll::Pending => {
+							*this.handshake = NotificationsInSubstreamHandshake::PendingSend(msg);
+							return Poll::Pending;
+						},
+					}
+				},
+				NotificationsInSubstreamHandshake::Flush => {
+					match Sink::poll_flush(this.socket.as_mut(), cx)? {
+						Poll::Ready(()) => {
+							*this.handshake = NotificationsInSubstreamHandshake::Sent;
+							return Poll::Ready(Ok(()));
+						},
+						Poll::Pending => {
+							*this.handshake = NotificationsInSubstreamHandshake::Flush;
+							return Poll::Pending;
+						},
+					}
+				},
+
+				st @ NotificationsInSubstreamHandshake::NotSent |
+				st @ NotificationsInSubstreamHandshake::Sent |
+				st @ NotificationsInSubstreamHandshake::ClosingInResponseToRemote |
+				st @ NotificationsInSubstreamHandshake::BothSidesClosed => {
+					*this.handshake = st;
+					return Poll::Ready(Ok(()));
+				},
+			}
+		}
+	}
+}
+
+impl<TSubstream> Stream for NotificationsInSubstream<TSubstream>
+where
+	TSubstream: AsyncRead + AsyncWrite + Unpin,
+{
+	type Item = Result<BytesMut, io::Error>;
+
+	fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+		let mut this = self.project();
+
+		// This `Stream` implementation first tries to send back the handshake if necessary.
+		loop {
+			match mem::replace(this.handshake, NotificationsInSubstreamHandshake::Sent) {
+				NotificationsInSubstreamHandshake::NotSent => {
+					*this.handshake = NotificationsInSubstreamHandshake::NotSent;
+					return Poll::Pending;
+				},
+				NotificationsInSubstreamHandshake::PendingSend(msg) => {
+					match Sink::poll_ready(this.socket.as_mut(), cx) {
+						Poll::Ready(_) => {
+							*this.handshake = NotificationsInSubstreamHandshake::Flush;
+							match Sink::start_send(this.socket.as_mut(), io::Cursor::new(msg)) {
+								Ok(()) => {},
+								Err(err) => return Poll::Ready(Some(Err(err))),
+							}
+						},
+						Poll::Pending => {
+							*this.handshake = NotificationsInSubstreamHandshake::PendingSend(msg);
+							return Poll::Pending;
+						},
+					}
+				},
+				NotificationsInSubstreamHandshake::Flush => {
+					match Sink::poll_flush(this.socket.as_mut(), cx)? {
+						Poll::Ready(()) =>
+							*this.handshake = NotificationsInSubstreamHandshake::Sent,
+						Poll::Pending => {
+							*this.handshake = NotificationsInSubstreamHandshake::Flush;
+							return Poll::Pending;
+						},
+					}
+				},
+
+				NotificationsInSubstreamHandshake::Sent => {
+					match Stream::poll_next(this.socket.as_mut(), cx) {
+						Poll::Ready(None) =>
+							*this.handshake =
+								NotificationsInSubstreamHandshake::ClosingInResponseToRemote,
+						Poll::Ready(Some(msg)) => {
+							*this.handshake = NotificationsInSubstreamHandshake::Sent;
+							return Poll::Ready(Some(msg));
+						},
+						Poll::Pending => {
+							*this.handshake = NotificationsInSubstreamHandshake::Sent;
+							return Poll::Pending;
+						},
+					}
+				},
+
+				NotificationsInSubstreamHandshake::ClosingInResponseToRemote =>
+					match Sink::poll_close(this.socket.as_mut(), cx)? {
+						Poll::Ready(()) =>
+							*this.handshake = NotificationsInSubstreamHandshake::BothSidesClosed,
+						Poll::Pending => {
+							*this.handshake =
+								NotificationsInSubstreamHandshake::ClosingInResponseToRemote;
+							return Poll::Pending;
+						},
+					},
+
+				NotificationsInSubstreamHandshake::BothSidesClosed => return Poll::Ready(None),
+			}
+		}
+	}
+}
+
+impl NotificationsOut {
+	/// Builds a new potential upgrade.
+	pub fn new(
+		main_protocol_name: impl Into<ProtocolName>,
+		fallback_names: Vec<ProtocolName>,
+		initial_message: impl Into<Vec<u8>>,
+		max_notification_size: u64,
+		peer_id: PeerId,
+	) -> Self {
+		let initial_message = initial_message.into();
+		if initial_message.len() > MAX_HANDSHAKE_SIZE {
+			error!(target: LOG_TARGET, "Outbound networking handshake is above allowed protocol limit");
+		}
+
+		let mut protocol_names = fallback_names;
+		protocol_names.insert(0, main_protocol_name.into());
+
+		Self { protocol_names, initial_message, max_notification_size, peer_id }
+	}
+}
+
+impl UpgradeInfo for NotificationsOut {
+	type Info = ProtocolName;
+	type InfoIter = vec::IntoIter<Self::Info>;
+
+	fn protocol_info(&self) -> Self::InfoIter {
+		self.protocol_names.clone().into_iter()
+	}
+}
+
+impl<TSubstream> OutboundUpgrade<TSubstream> for NotificationsOut
+where
+	TSubstream: AsyncRead + AsyncWrite + Unpin + Send + 'static,
+{
+	type Output = NotificationsOutOpen<TSubstream>;
+	type Future = Pin<Box<dyn Future<Output = Result<Self::Output, Self::Error>> + Send>>;
+	type Error = NotificationsHandshakeError;
+
+	fn upgrade_outbound(self, mut socket: TSubstream, negotiated_name: Self::Info) -> Self::Future {
+		Box::pin(async move {
+			{
+				let mut len_data = unsigned_varint::encode::usize_buffer();
+				let encoded_len =
+					unsigned_varint::encode::usize(self.initial_message.len(), &mut len_data).len();
+				socket.write_all(&len_data[..encoded_len]).await?;
+			}
+			socket.write_all(&self.initial_message).await?;
+			socket.flush().await?;
+
+			// Reading handshake.
+			let handshake_len = unsigned_varint::aio::read_usize(&mut socket).await?;
+			if handshake_len > MAX_HANDSHAKE_SIZE {
+				return Err(NotificationsHandshakeError::TooLarge {
+					requested: handshake_len,
+					max: MAX_HANDSHAKE_SIZE,
+				});
+			}
+
+			let mut handshake = vec![0u8; handshake_len];
+			if !handshake.is_empty() {
+				socket.read_exact(&mut handshake).await?;
+			}
+
+			let mut codec = UviBytes::default();
+			codec.set_max_len(usize::try_from(self.max_notification_size).unwrap_or(usize::MAX));
+
+			Ok(NotificationsOutOpen {
+				handshake,
+				negotiated_fallback: if negotiated_name == self.protocol_names[0] {
+					None
+				} else {
+					Some(negotiated_name)
+				},
+				substream: NotificationsOutSubstream {
+					socket: Framed::new(socket, codec),
+					peer_id: self.peer_id,
+				},
+			})
+		})
+	}
+}
+
+/// Yielded by the [`NotificationsOut`] after a successfully upgrade.
+pub struct NotificationsOutOpen<TSubstream> {
+	/// Handshake returned by the remote.
+	pub handshake: Vec<u8>,
+	/// If the negotiated name is not the "main" protocol name but a fallback, contains the
+	/// name of the negotiated fallback.
+	pub negotiated_fallback: Option<ProtocolName>,
+	/// Implementation of `Sink` that allows sending messages on the substream.
+	pub substream: NotificationsOutSubstream<TSubstream>,
+}
+
+impl<TSubstream> fmt::Debug for NotificationsOutOpen<TSubstream> {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		f.debug_struct("NotificationsOutOpen")
+			.field("handshake", &self.handshake)
+			.field("negotiated_fallback", &self.negotiated_fallback)
+			.finish_non_exhaustive()
+	}
+}
+
+impl<TSubstream> Sink<Vec<u8>> for NotificationsOutSubstream<TSubstream>
+where
+	TSubstream: AsyncRead + AsyncWrite + Unpin,
+{
+	type Error = NotificationsOutError;
+
+	fn poll_ready(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
+		let mut this = self.project();
+		Sink::poll_ready(this.socket.as_mut(), cx).map_err(NotificationsOutError::Io)
+	}
+
+	fn start_send(self: Pin<&mut Self>, item: Vec<u8>) -> Result<(), Self::Error> {
+		let mut this = self.project();
+		Sink::start_send(this.socket.as_mut(), io::Cursor::new(item))
+			.map_err(NotificationsOutError::Io)
+	}
+
+	fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
+		let mut this = self.project();
+
+		// `Sink::poll_flush` does not expose stream closed error until we write something into
+		// the stream, so the code below makes sure we detect that the substream was closed
+		// even if we don't write anything into it.
+		match Stream::poll_next(this.socket.as_mut(), cx) {
+			Poll::Pending => {},
+			Poll::Ready(Some(result)) => match result {
+				Ok(_) => {
+					debug!(
+						target: "sub-libp2p",
+						"Unexpected incoming data in `NotificationsOutSubstream` peer={:?}",
+						this.peer_id
+					);
+
+					return Poll::Ready(Err(NotificationsOutError::UnexpectedData));
+				},
+				Err(error) => {
+					debug!(
+						target: "sub-libp2p",
+						"Error while reading from `NotificationsOutSubstream` peer={:?} error={error:?}",
+						this.peer_id
+					);
+
+					// The expectation is that the remote has closed the substream.
+					return Poll::Ready(Err(NotificationsOutError::Closed));
+				},
+			},
+			Poll::Ready(None) => return Poll::Ready(Err(NotificationsOutError::Closed)),
+		}
+
+		Sink::poll_flush(this.socket.as_mut(), cx).map_err(NotificationsOutError::Io)
+	}
+
+	fn poll_close(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
+		let mut this = self.project();
+		Sink::poll_close(this.socket.as_mut(), cx).map_err(NotificationsOutError::Io)
+	}
+}
+
+/// Error generated by sending on a notifications out substream.
+#[derive(Debug, thiserror::Error)]
+pub enum NotificationsHandshakeError {
+	/// I/O error on the substream.
+	#[error(transparent)]
+	Io(#[from] io::Error),
+
+	/// Initial message or handshake was too large.
+	#[error("Initial message or handshake was too large: {requested}")]
+	TooLarge {
+		/// Size requested by the remote.
+		requested: usize,
+		/// Maximum allowed,
+		max: usize,
+	},
+
+	/// Error while decoding the variable-length integer.
+	#[error(transparent)]
+	VarintDecode(#[from] unsigned_varint::decode::Error),
+}
+
+impl From<unsigned_varint::io::ReadError> for NotificationsHandshakeError {
+	fn from(err: unsigned_varint::io::ReadError) -> Self {
+		match err {
+			unsigned_varint::io::ReadError::Io(err) => Self::Io(err),
+			unsigned_varint::io::ReadError::Decode(err) => Self::VarintDecode(err),
+			_ => {
+				warn!("Unrecognized varint decoding error");
+				Self::Io(From::from(io::ErrorKind::InvalidData))
+			},
+		}
+	}
+}
+
+/// Error generated by sending on a notifications out substream.
+#[derive(Debug, thiserror::Error)]
+pub enum NotificationsOutError {
+	/// I/O error on the substream.
+	#[error(transparent)]
+	Io(#[from] io::Error),
+
+	/// The substream was closed.
+	#[error("substream was closed/reset")]
+	Closed,
+
+	/// The remote peer did not comply with the notification spec.
+	///
+	/// This is a terminal error and the peer should be banned immediately.
+	#[error("unexpected data received from the remote peer")]
+	UnexpectedData,
+}
+
+#[cfg(test)]
+mod tests {
+	use crate::ProtocolName;
+
+	use super::{
+		NotificationsHandshakeError, NotificationsIn, NotificationsInOpen,
+		NotificationsInSubstream, NotificationsOut, NotificationsOutError, NotificationsOutOpen,
+		NotificationsOutSubstream,
+	};
+	use futures::{channel::oneshot, future, prelude::*, SinkExt, StreamExt};
+	use libp2p::{
+		core::{upgrade, InboundUpgrade, OutboundUpgrade, UpgradeInfo},
+		PeerId,
+	};
+	use std::{pin::Pin, task::Poll};
+	use tokio::net::{TcpListener, TcpStream};
+	use tokio_util::compat::TokioAsyncReadCompatExt;
+
+	/// Opens a substream to the given address, negotiates the protocol, and returns the substream
+	/// along with the handshake message.
+	async fn dial(
+		addr: std::net::SocketAddr,
+		handshake: impl Into<Vec<u8>>,
+	) -> Result<
+		(
+			Vec<u8>,
+			NotificationsOutSubstream<
+				multistream_select::Negotiated<tokio_util::compat::Compat<TcpStream>>,
+			>,
+		),
+		NotificationsHandshakeError,
+	> {
+		let socket = TcpStream::connect(addr).await.unwrap();
+		let notifs_out = NotificationsOut::new(
+			"/test/proto/1",
+			Vec::new(),
+			handshake,
+			1024 * 1024,
+			PeerId::random(),
+		);
+		let (_, substream) = multistream_select::dialer_select_proto(
+			socket.compat(),
+			notifs_out.protocol_info(),
+			upgrade::Version::V1,
+		)
+		.await
+		.unwrap();
+		let NotificationsOutOpen { handshake, substream, .. } =
+			<NotificationsOut as OutboundUpgrade<_>>::upgrade_outbound(
+				notifs_out,
+				substream,
+				"/test/proto/1".into(),
+			)
+			.await?;
+		Ok((handshake, substream))
+	}
+
+	/// Listens on a localhost, negotiates the protocol, and returns the substream along with the
+	/// handshake message.
+	///
+	/// Also sends the listener address through the given channel.
+	async fn listen_on_localhost(
+		listener_addr_tx: oneshot::Sender<std::net::SocketAddr>,
+	) -> Result<
+		(
+			Vec<u8>,
+			NotificationsInSubstream<
+				multistream_select::Negotiated<tokio_util::compat::Compat<TcpStream>>,
+			>,
+		),
+		NotificationsHandshakeError,
+	> {
+		let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+		listener_addr_tx.send(listener.local_addr().unwrap()).unwrap();
+
+		let (socket, _) = listener.accept().await.unwrap();
+		let notifs_in = NotificationsIn::new("/test/proto/1", Vec::new(), 1024 * 1024);
+		let (_, substream) =
+			multistream_select::listener_select_proto(socket.compat(), notifs_in.protocol_info())
+				.await
+				.unwrap();
+		let NotificationsInOpen { handshake, substream, .. } =
+			<NotificationsIn as InboundUpgrade<_>>::upgrade_inbound(
+				notifs_in,
+				substream,
+				"/test/proto/1".into(),
+			)
+			.await?;
+		Ok((handshake, substream))
+	}
+
+	#[tokio::test]
+	async fn basic_works() {
+		let (listener_addr_tx, listener_addr_rx) = oneshot::channel();
+
+		let client = tokio::spawn(async move {
+			let (handshake, mut substream) =
+				dial(listener_addr_rx.await.unwrap(), &b"initial message"[..]).await.unwrap();
+
+			assert_eq!(handshake, b"hello world");
+			substream.send(b"test message".to_vec()).await.unwrap();
+		});
+
+		let (handshake, mut substream) = listen_on_localhost(listener_addr_tx).await.unwrap();
+
+		assert_eq!(handshake, b"initial message");
+		substream.send_handshake(&b"hello world"[..]);
+
+		let msg = substream.next().await.unwrap().unwrap();
+		assert_eq!(msg.as_ref(), b"test message");
+
+		client.await.unwrap();
+	}
+
+	#[tokio::test]
+	async fn empty_handshake() {
+		// Check that everything still works when the handshake messages are empty.
+
+		let (listener_addr_tx, listener_addr_rx) = oneshot::channel();
+
+		let client = tokio::spawn(async move {
+			let (handshake, mut substream) =
+				dial(listener_addr_rx.await.unwrap(), vec![]).await.unwrap();
+
+			assert!(handshake.is_empty());
+			substream.send(Default::default()).await.unwrap();
+		});
+
+		let (handshake, mut substream) = listen_on_localhost(listener_addr_tx).await.unwrap();
+
+		assert!(handshake.is_empty());
+		substream.send_handshake(vec![]);
+
+		let msg = substream.next().await.unwrap().unwrap();
+		assert!(msg.as_ref().is_empty());
+
+		client.await.unwrap();
+	}
+
+	#[tokio::test]
+	async fn refused() {
+		let (listener_addr_tx, listener_addr_rx) = oneshot::channel();
+
+		let client = tokio::spawn(async move {
+			let outcome = dial(listener_addr_rx.await.unwrap(), &b"hello"[..]).await;
+
+			// Despite the protocol negotiation being successfully conducted on the listener
+			// side, we have to receive an error here because the listener didn't send the
+			// handshake.
+			assert!(outcome.is_err());
+		});
+
+		let (handshake, substream) = listen_on_localhost(listener_addr_tx).await.unwrap();
+		assert_eq!(handshake, b"hello");
+
+		// We successfully upgrade to the protocol, but then close the substream.
+		drop(substream);
+
+		client.await.unwrap();
+	}
+
+	#[tokio::test]
+	async fn large_initial_message_refused() {
+		let (listener_addr_tx, listener_addr_rx) = oneshot::channel();
+
+		let client = tokio::spawn(async move {
+			let ret =
+				dial(listener_addr_rx.await.unwrap(), (0..32768).map(|_| 0).collect::<Vec<_>>())
+					.await;
+			assert!(ret.is_err());
+		});
+
+		let _ret = listen_on_localhost(listener_addr_tx).await;
+		client.await.unwrap();
+	}
+
+	#[tokio::test]
+	async fn large_handshake_refused() {
+		let (listener_addr_tx, listener_addr_rx) = oneshot::channel();
+
+		let client = tokio::spawn(async move {
+			let ret = dial(listener_addr_rx.await.unwrap(), &b"initial message"[..]).await;
+			assert!(ret.is_err());
+		});
+
+		let (handshake, mut substream) = listen_on_localhost(listener_addr_tx).await.unwrap();
+		assert_eq!(handshake, b"initial message");
+
+		// We check that a handshake that is too large gets refused.
+		substream.send_handshake((0..32768).map(|_| 0).collect::<Vec<_>>());
+		let _ = substream.next().await;
+
+		client.await.unwrap();
+	}
+
+	#[tokio::test]
+	async fn send_handshake_without_polling_for_incoming_data() {
+		const PROTO_NAME: &str = "/test/proto/1";
+		let (listener_addr_tx, listener_addr_rx) = oneshot::channel();
+
+		let client = tokio::spawn(async move {
+			let socket = TcpStream::connect(listener_addr_rx.await.unwrap()).await.unwrap();
+			let NotificationsOutOpen { handshake, .. } = OutboundUpgrade::upgrade_outbound(
+				NotificationsOut::new(
+					PROTO_NAME,
+					Vec::new(),
+					&b"initial message"[..],
+					1024 * 1024,
+					PeerId::random(),
+				),
+				socket.compat(),
+				ProtocolName::Static(PROTO_NAME),
+			)
+			.await
+			.unwrap();
+
+			assert_eq!(handshake, b"hello world");
+		});
+
+		let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+		listener_addr_tx.send(listener.local_addr().unwrap()).unwrap();
+
+		let (socket, _) = listener.accept().await.unwrap();
+		let NotificationsInOpen { handshake, mut substream, .. } = InboundUpgrade::upgrade_inbound(
+			NotificationsIn::new(PROTO_NAME, Vec::new(), 1024 * 1024),
+			socket.compat(),
+			ProtocolName::Static(PROTO_NAME),
+		)
+		.await
+		.unwrap();
+
+		assert_eq!(handshake, b"initial message");
+		substream.send_handshake(&b"hello world"[..]);
+
+		// Actually send the handshake.
+		future::poll_fn(|cx| Pin::new(&mut substream).poll_process(cx)).await.unwrap();
+
+		client.await.unwrap();
+	}
+
+	#[tokio::test]
+	async fn can_detect_dropped_out_substream_without_writing_data() {
+		const PROTO_NAME: &str = "/test/proto/1";
+		let (listener_addr_tx, listener_addr_rx) = oneshot::channel();
+
+		let client = tokio::spawn(async move {
+			let socket = TcpStream::connect(listener_addr_rx.await.unwrap()).await.unwrap();
+			let NotificationsOutOpen { handshake, mut substream, .. } =
+				OutboundUpgrade::upgrade_outbound(
+					NotificationsOut::new(
+						PROTO_NAME,
+						Vec::new(),
+						&b"initial message"[..],
+						1024 * 1024,
+						PeerId::random(),
+					),
+					socket.compat(),
+					ProtocolName::Static(PROTO_NAME),
+				)
+				.await
+				.unwrap();
+
+			assert_eq!(handshake, b"hello world");
+
+			future::poll_fn(|cx| match Pin::new(&mut substream).poll_flush(cx) {
+				Poll::Pending => Poll::Pending,
+				Poll::Ready(Ok(())) => {
+					cx.waker().wake_by_ref();
+					Poll::Pending
+				},
+				Poll::Ready(Err(e)) => {
+					assert!(matches!(e, NotificationsOutError::Closed));
+					Poll::Ready(())
+				},
+			})
+			.await;
+		});
+
+		let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+		listener_addr_tx.send(listener.local_addr().unwrap()).unwrap();
+
+		let (socket, _) = listener.accept().await.unwrap();
+		let NotificationsInOpen { handshake, mut substream, .. } = InboundUpgrade::upgrade_inbound(
+			NotificationsIn::new(PROTO_NAME, Vec::new(), 1024 * 1024),
+			socket.compat(),
+			ProtocolName::Static(PROTO_NAME),
+		)
+		.await
+		.unwrap();
+
+		assert_eq!(handshake, b"initial message");
+
+		// Send the handhsake.
+		substream.send_handshake(&b"hello world"[..]);
+		future::poll_fn(|cx| Pin::new(&mut substream).poll_process(cx)).await.unwrap();
+
+		drop(substream);
+
+		client.await.unwrap();
+	}
+}

bizinikiwi/client/network/src/schema/bitswap.v1.2.0.proto

@@ -0,0 +1,43 @@
+syntax = "proto3";
+
+package bitswap.message;
+
+message Message {
+	message Wantlist {
+		enum WantType {
+			Block = 0;
+			Have = 1;
+		}
+
+		message Entry {
+			bytes block = 1; 	// the block cid (cidV0 in bitswap 1.0.0, cidV1 in bitswap 1.1.0)
+			int32 priority = 2;	// the priority (normalized). default to 1
+			bool cancel = 3;		// whether this revokes an entry
+			WantType wantType = 4; // Note: defaults to enum 0, ie Block
+			bool sendDontHave = 5; // Note: defaults to false
+		}
+
+		repeated Entry entries = 1; // a list of wantlist entries
+		bool full = 2;							// whether this is the full wantlist. default to false
+	}
+
+	message Block {
+		bytes prefix = 1;		// CID prefix (cid version, multicodec and multihash prefix (type + length)
+		bytes data = 2;
+	}
+
+	enum BlockPresenceType {
+		Have = 0;
+		DontHave = 1;
+	}
+	message BlockPresence {
+		bytes cid = 1;
+		BlockPresenceType type = 2;
+	}
+
+	Wantlist wantlist = 1;
+	repeated bytes blocks = 2;		// used to send Blocks in bitswap 1.0.0
+	repeated Block payload = 3;		// used to send Blocks in bitswap 1.1.0
+	repeated BlockPresence blockPresences = 4;
+	int32 pendingBytes = 5;
+}

bizinikiwi/client/network/src/service/metrics.rs

@@ -0,0 +1,414 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::{service::traits::BandwidthSink, ProtocolName};
+
+use prometheus_endpoint::{
+	self as prometheus, Counter, CounterVec, Gauge, GaugeVec, HistogramOpts, MetricSource, Opts,
+	PrometheusError, Registry, SourcedCounter, SourcedGauge, U64,
+};
+
+use std::{
+	str,
+	sync::{
+		atomic::{AtomicUsize, Ordering},
+		Arc,
+	},
+};
+
+pub use prometheus_endpoint::{Histogram, HistogramVec};
+
+/// Registers all networking metrics with the given registry.
+pub fn register(registry: &Registry, sources: MetricSources) -> Result<Metrics, PrometheusError> {
+	BandwidthCounters::register(registry, sources.bandwidth)?;
+	NumConnectedGauge::register(registry, sources.connected_peers)?;
+	Metrics::register(registry)
+}
+
+// Register `sc-network` metrics without bandwidth/connected peer sources.
+pub fn register_without_sources(registry: &Registry) -> Result<Metrics, PrometheusError> {
+	Metrics::register(registry)
+}
+
+/// Predefined metric sources that are fed directly into prometheus.
+pub struct MetricSources {
+	pub bandwidth: Arc<dyn BandwidthSink>,
+	pub connected_peers: Arc<AtomicUsize>,
+}
+
+impl MetricSources {
+	pub fn register(
+		registry: &Registry,
+		bandwidth: Arc<dyn BandwidthSink>,
+		connected_peers: Arc<AtomicUsize>,
+	) -> Result<(), PrometheusError> {
+		BandwidthCounters::register(registry, bandwidth)?;
+		NumConnectedGauge::register(registry, connected_peers)
+	}
+}
+
+/// Dedicated metrics.
+#[derive(Clone)]
+pub struct Metrics {
+	// This list is ordered alphabetically
+	pub connections_closed_total: CounterVec<U64>,
+	pub connections_opened_total: CounterVec<U64>,
+	pub distinct_peers_connections_closed_total: Counter<U64>,
+	pub distinct_peers_connections_opened_total: Counter<U64>,
+	pub incoming_connections_errors_total: CounterVec<U64>,
+	pub incoming_connections_total: Counter<U64>,
+	pub kademlia_query_duration: HistogramVec,
+	pub kademlia_random_queries_total: Counter<U64>,
+	pub kademlia_records_count: Gauge<U64>,
+	pub kademlia_records_sizes_total: Gauge<U64>,
+	pub kbuckets_num_nodes: GaugeVec<U64>,
+	pub listeners_local_addresses: Gauge<U64>,
+	pub listeners_errors_total: Counter<U64>,
+	pub pending_connections: Gauge<U64>,
+	pub pending_connections_errors_total: CounterVec<U64>,
+	pub requests_in_failure_total: CounterVec<U64>,
+	pub requests_in_success_total: HistogramVec,
+	pub requests_out_failure_total: CounterVec<U64>,
+	pub requests_out_success_total: HistogramVec,
+}
+
+impl Metrics {
+	fn register(registry: &Registry) -> Result<Self, PrometheusError> {
+		Ok(Self {
+			// This list is ordered alphabetically
+			connections_closed_total: prometheus::register(CounterVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_connections_closed_total",
+					"Total number of connections closed, by direction and reason"
+				),
+				&["direction", "reason"]
+			)?, registry)?,
+			connections_opened_total: prometheus::register(CounterVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_connections_opened_total",
+					"Total number of connections opened by direction"
+				),
+				&["direction"]
+			)?, registry)?,
+			distinct_peers_connections_closed_total: prometheus::register(Counter::new(
+					"bizinikiwi_sub_libp2p_distinct_peers_connections_closed_total",
+					"Total number of connections closed with distinct peers"
+			)?, registry)?,
+			distinct_peers_connections_opened_total: prometheus::register(Counter::new(
+					"bizinikiwi_sub_libp2p_distinct_peers_connections_opened_total",
+					"Total number of connections opened with distinct peers"
+			)?, registry)?,
+			incoming_connections_errors_total: prometheus::register(CounterVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_incoming_connections_handshake_errors_total",
+					"Total number of incoming connections that have failed during the \
+					initial handshake"
+				),
+				&["reason"]
+			)?, registry)?,
+			incoming_connections_total: prometheus::register(Counter::new(
+				"bizinikiwi_sub_libp2p_incoming_connections_total",
+				"Total number of incoming connections on the listening sockets"
+			)?, registry)?,
+			kademlia_query_duration: prometheus::register(HistogramVec::new(
+				HistogramOpts {
+					common_opts: Opts::new(
+						"bizinikiwi_sub_libp2p_kademlia_query_duration",
+						"Duration of Kademlia queries per query type"
+					),
+					buckets: prometheus::exponential_buckets(0.5, 2.0, 10)
+						.expect("parameters are always valid values; qed"),
+				},
+				&["type"]
+			)?, registry)?,
+			kademlia_random_queries_total: prometheus::register(Counter::new(
+				"bizinikiwi_sub_libp2p_kademlia_random_queries_total",
+				"Number of random Kademlia queries started",
+			)?, registry)?,
+			kademlia_records_count: prometheus::register(Gauge::new(
+				"bizinikiwi_sub_libp2p_kademlia_records_count",
+				"Number of records in the Kademlia records store",
+			)?, registry)?,
+			kademlia_records_sizes_total: prometheus::register(Gauge::new(
+				"bizinikiwi_sub_libp2p_kademlia_records_sizes_total",
+				"Total size of all the records in the Kademlia records store",
+			)?, registry)?,
+			kbuckets_num_nodes: prometheus::register(GaugeVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_kbuckets_num_nodes",
+					"Number of nodes per kbucket per Kademlia instance"
+				),
+				&["lower_ilog2_bucket_bound"]
+			)?, registry)?,
+			listeners_local_addresses: prometheus::register(Gauge::new(
+				"bizinikiwi_sub_libp2p_listeners_local_addresses",
+				"Number of local addresses we're listening on"
+			)?, registry)?,
+			listeners_errors_total: prometheus::register(Counter::new(
+				"bizinikiwi_sub_libp2p_listeners_errors_total",
+				"Total number of non-fatal errors reported by a listener"
+			)?, registry)?,
+			pending_connections: prometheus::register(Gauge::new(
+				"bizinikiwi_sub_libp2p_pending_connections",
+				"Number of connections in the process of being established",
+			)?, registry)?,
+			pending_connections_errors_total: prometheus::register(CounterVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_pending_connections_errors_total",
+					"Total number of pending connection errors"
+				),
+				&["reason"]
+			)?, registry)?,
+			requests_in_failure_total: prometheus::register(CounterVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_requests_in_failure_total",
+					"Total number of incoming requests that the node has failed to answer"
+				),
+				&["protocol", "reason"]
+			)?, registry)?,
+			requests_in_success_total: prometheus::register(HistogramVec::new(
+				HistogramOpts {
+					common_opts: Opts::new(
+						"bizinikiwi_sub_libp2p_requests_in_success_total",
+						"For successful incoming requests, time between receiving the request and \
+						 starting to send the response"
+					),
+					buckets: prometheus::exponential_buckets(0.001, 2.0, 16)
+						.expect("parameters are always valid values; qed"),
+				},
+				&["protocol"]
+			)?, registry)?,
+			requests_out_failure_total: prometheus::register(CounterVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_requests_out_failure_total",
+					"Total number of requests that have failed"
+				),
+				&["protocol", "reason"]
+			)?, registry)?,
+			requests_out_success_total: prometheus::register(HistogramVec::new(
+				HistogramOpts {
+					common_opts: Opts::new(
+						"bizinikiwi_sub_libp2p_requests_out_success_total",
+						"For successful outgoing requests, time between a request's start and finish"
+					),
+					buckets: prometheus::exponential_buckets(0.001, 2.0, 16)
+						.expect("parameters are always valid values; qed"),
+				},
+				&["protocol"]
+			)?, registry)?,
+		})
+	}
+}
+
+/// Peer store metrics.
+#[derive(Clone, Debug)]
+pub struct PeerStoreMetrics {
+	pub num_banned_peers: Gauge<U64>,
+	pub num_discovered: Gauge<U64>,
+}
+
+impl PeerStoreMetrics {
+	pub fn register(registry: &Registry) -> Result<Self, PrometheusError> {
+		Ok(Self {
+			num_banned_peers: prometheus::register(
+				Gauge::new(
+					"bizinikiwi_sub_libp2p_peerset_num_banned_peers",
+					"Number of banned peers stored in the peerset manager",
+				)?,
+				registry,
+			)?,
+			num_discovered: prometheus::register(
+				Gauge::new(
+					"bizinikiwi_sub_libp2p_peerset_num_discovered",
+					"Number of nodes stored in the peerset manager",
+				)?,
+				registry,
+			)?,
+		})
+	}
+}
+
+/// The bandwidth counter metric.
+#[derive(Clone)]
+pub struct BandwidthCounters(Arc<dyn BandwidthSink>);
+
+impl BandwidthCounters {
+	/// Registers the `BandwidthCounters` metric whose values are
+	/// obtained from the given sinks.
+	fn register(registry: &Registry, sinks: Arc<dyn BandwidthSink>) -> Result<(), PrometheusError> {
+		prometheus::register(
+			SourcedCounter::new(
+				&Opts::new("bizinikiwi_sub_libp2p_network_bytes_total", "Total bandwidth usage")
+					.variable_label("direction"),
+				BandwidthCounters(sinks),
+			)?,
+			registry,
+		)?;
+
+		Ok(())
+	}
+}
+
+impl MetricSource for BandwidthCounters {
+	type N = u64;
+
+	fn collect(&self, mut set: impl FnMut(&[&str], Self::N)) {
+		set(&["in"], self.0.total_inbound());
+		set(&["out"], self.0.total_outbound());
+	}
+}
+
+/// The connected peers metric.
+#[derive(Clone)]
+pub struct NumConnectedGauge(Arc<AtomicUsize>);
+
+impl NumConnectedGauge {
+	/// Registers the `MajorSyncingGauge` metric whose value is
+	/// obtained from the given `AtomicUsize`.
+	fn register(registry: &Registry, value: Arc<AtomicUsize>) -> Result<(), PrometheusError> {
+		prometheus::register(
+			SourcedGauge::new(
+				&Opts::new("bizinikiwi_sub_libp2p_peers_count", "Number of connected peers"),
+				NumConnectedGauge(value),
+			)?,
+			registry,
+		)?;
+
+		Ok(())
+	}
+}
+
+impl MetricSource for NumConnectedGauge {
+	type N = u64;
+
+	fn collect(&self, mut set: impl FnMut(&[&str], Self::N)) {
+		set(&[], self.0.load(Ordering::Relaxed) as u64);
+	}
+}
+
+/// Notification metrics.
+///
+/// Wrapper over `Option<InnerNotificationMetrics>` to make metrics reporting code cleaner.
+#[derive(Debug, Clone)]
+pub struct NotificationMetrics {
+	/// Metrics, if enabled.
+	metrics: Option<InnerNotificationMetrics>,
+}
+
+impl NotificationMetrics {
+	/// Create new [`NotificationMetrics`].
+	pub fn new(registry: Option<&Registry>) -> NotificationMetrics {
+		let metrics = match registry {
+			Some(registry) => InnerNotificationMetrics::register(registry).ok(),
+			None => None,
+		};
+
+		Self { metrics }
+	}
+
+	/// Register opened substream to Prometheus.
+	pub fn register_substream_opened(&self, protocol: &ProtocolName) {
+		if let Some(metrics) = &self.metrics {
+			metrics.notifications_streams_opened_total.with_label_values(&[&protocol]).inc();
+		}
+	}
+
+	/// Register closed substream to Prometheus.
+	pub fn register_substream_closed(&self, protocol: &ProtocolName) {
+		if let Some(metrics) = &self.metrics {
+			metrics
+				.notifications_streams_closed_total
+				.with_label_values(&[&protocol[..]])
+				.inc();
+		}
+	}
+
+	/// Register sent notification to Prometheus.
+	pub fn register_notification_sent(&self, protocol: &ProtocolName, size: usize) {
+		if let Some(metrics) = &self.metrics {
+			metrics
+				.notifications_sizes
+				.with_label_values(&["out", protocol])
+				.observe(size as f64);
+		}
+	}
+
+	/// Register received notification to Prometheus.
+	pub fn register_notification_received(&self, protocol: &ProtocolName, size: usize) {
+		if let Some(metrics) = &self.metrics {
+			metrics
+				.notifications_sizes
+				.with_label_values(&["in", protocol])
+				.observe(size as f64);
+		}
+	}
+}
+
+/// Notification metrics.
+#[derive(Debug, Clone)]
+struct InnerNotificationMetrics {
+	// Total number of opened substreams.
+	pub notifications_streams_opened_total: CounterVec<U64>,
+
+	/// Total number of closed substreams.
+	pub notifications_streams_closed_total: CounterVec<U64>,
+
+	/// In/outbound notification sizes.
+	pub notifications_sizes: HistogramVec,
+}
+
+impl InnerNotificationMetrics {
+	fn register(registry: &Registry) -> Result<Self, PrometheusError> {
+		Ok(Self {
+			notifications_sizes: prometheus::register(
+				HistogramVec::new(
+					HistogramOpts {
+						common_opts: Opts::new(
+							"bizinikiwi_sub_libp2p_notifications_sizes",
+							"Sizes of the notifications send to and received from all nodes",
+						),
+						buckets: prometheus::exponential_buckets(64.0, 4.0, 8)
+							.expect("parameters are always valid values; qed"),
+					},
+					&["direction", "protocol"],
+				)?,
+				registry,
+			)?,
+			notifications_streams_closed_total: prometheus::register(
+				CounterVec::new(
+					Opts::new(
+						"bizinikiwi_sub_libp2p_notifications_streams_closed_total",
+						"Total number of notification substreams that have been closed",
+					),
+					&["protocol"],
+				)?,
+				registry,
+			)?,
+			notifications_streams_opened_total: prometheus::register(
+				CounterVec::new(
+					Opts::new(
+						"bizinikiwi_sub_libp2p_notifications_streams_opened_total",
+						"Total number of notification substreams that have been opened",
+					),
+					&["protocol"],
+				)?,
+				registry,
+			)?,
+		})
+	}
+}

bizinikiwi/client/network/src/service/out_events.rs

@@ -0,0 +1,347 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Registering events streams.
+//!
+//! This code holds the logic that is used for the network service to inform other parts of
+//! Bizinikiwi about what is happening.
+//!
+//! # Usage
+//!
+//! - Create an instance of [`OutChannels`].
+//! - Create channels using the [`channel`] function. The receiving side implements the `Stream`
+//! trait.
+//! - You cannot directly send an event on a sender. Instead, you have to call
+//! [`OutChannels::push`] to put the sender within a [`OutChannels`].
+//! - Send events by calling [`OutChannels::send`]. Events are cloned for each sender in the
+//! collection.
+
+use crate::event::Event;
+
+use futures::{prelude::*, ready, stream::FusedStream};
+use log::{debug, error};
+use prometheus_endpoint::{register, CounterVec, GaugeVec, Opts, PrometheusError, Registry, U64};
+use std::{
+	backtrace::Backtrace,
+	cell::RefCell,
+	fmt,
+	pin::Pin,
+	task::{Context, Poll},
+};
+
+/// Log target for this file.
+pub const LOG_TARGET: &str = "sub-libp2p::out_events";
+
+/// Creates a new channel that can be associated to a [`OutChannels`].
+///
+/// The name is used in Prometheus reports, the queue size threshold is used
+/// to warn if there are too many unprocessed events in the channel.
+pub fn channel(name: &'static str, queue_size_warning: usize) -> (Sender, Receiver) {
+	let (tx, rx) = async_channel::unbounded();
+	let tx = Sender {
+		inner: tx,
+		name,
+		queue_size_warning,
+		warning_fired: SenderWarningState::NotFired,
+		creation_backtrace: Backtrace::force_capture(),
+		metrics: None,
+	};
+	let rx = Receiver { inner: rx, name, metrics: None };
+	(tx, rx)
+}
+
+/// A state of a sender warning that is used to avoid spamming the logs.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum SenderWarningState {
+	/// The warning has not been fired yet.
+	NotFired,
+	/// The warning has been fired, and the channel is full
+	FiredFull,
+	/// The warning has been fired and the channel is not full anymore.
+	FiredFree,
+}
+
+/// Sending side of a channel.
+///
+/// Must be associated with an [`OutChannels`] before anything can be sent on it
+///
+/// > **Note**: Contrary to regular channels, this `Sender` is purposefully designed to not
+/// implement the `Clone` trait e.g. in Order to not complicate the logic keeping the metrics in
+/// sync on drop. If someone adds a `#[derive(Clone)]` below, it is **wrong**.
+pub struct Sender {
+	inner: async_channel::Sender<Event>,
+	/// Name to identify the channel (e.g., in Prometheus and logs).
+	name: &'static str,
+	/// Threshold queue size to generate an error message in the logs.
+	queue_size_warning: usize,
+	/// We generate the error message only once to not spam the logs after the first error.
+	/// Subsequently we indicate channel fullness on debug level.
+	warning_fired: SenderWarningState,
+	/// Backtrace of a place where the channel was created.
+	creation_backtrace: Backtrace,
+	/// Clone of [`Receiver::metrics`]. Will be initialized when [`Sender`] is added to
+	/// [`OutChannels`] with `OutChannels::push()`.
+	metrics: Option<Metrics>,
+}
+
+impl fmt::Debug for Sender {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		f.debug_tuple("Sender").finish()
+	}
+}
+
+impl Drop for Sender {
+	fn drop(&mut self) {
+		if let Some(metrics) = self.metrics.as_ref() {
+			metrics.num_channels.with_label_values(&[self.name]).dec();
+		}
+	}
+}
+
+/// Receiving side of a channel.
+pub struct Receiver {
+	inner: async_channel::Receiver<Event>,
+	name: &'static str,
+	/// Initially contains `None`, and will be set to a value once the corresponding [`Sender`]
+	/// is assigned to an instance of [`OutChannels`].
+	metrics: Option<Metrics>,
+}
+
+impl Stream for Receiver {
+	type Item = Event;
+
+	fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Event>> {
+		if let Some(ev) = ready!(Pin::new(&mut self.inner).poll_next(cx)) {
+			if let Some(metrics) = &self.metrics {
+				metrics.event_out(&ev, self.name);
+			}
+			Poll::Ready(Some(ev))
+		} else {
+			Poll::Ready(None)
+		}
+	}
+}
+
+impl fmt::Debug for Receiver {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		f.debug_tuple("Receiver").finish()
+	}
+}
+
+impl Drop for Receiver {
+	fn drop(&mut self) {
+		if !self.inner.is_terminated() {
+			// Empty the list to properly decrease the metrics.
+			while let Some(Some(_)) = self.next().now_or_never() {}
+		}
+	}
+}
+
+/// Collection of senders.
+pub struct OutChannels {
+	event_streams: Vec<Sender>,
+	/// The metrics we collect. A clone of this is sent to each [`Receiver`] associated with this
+	/// object.
+	metrics: Option<Metrics>,
+}
+
+impl OutChannels {
+	/// Creates a new empty collection of senders.
+	pub fn new(registry: Option<&Registry>) -> Result<Self, PrometheusError> {
+		let metrics =
+			if let Some(registry) = registry { Some(Metrics::register(registry)?) } else { None };
+
+		Ok(Self { event_streams: Vec::new(), metrics })
+	}
+
+	/// Adds a new [`Sender`] to the collection.
+	pub fn push(&mut self, mut sender: Sender) {
+		debug_assert!(sender.metrics.is_none());
+		sender.metrics = self.metrics.clone();
+
+		if let Some(metrics) = &self.metrics {
+			metrics.num_channels.with_label_values(&[sender.name]).inc();
+		}
+
+		self.event_streams.push(sender);
+	}
+
+	/// Sends an event.
+	pub fn send(&mut self, event: Event) {
+		self.event_streams.retain_mut(|sender| {
+			let current_pending = sender.inner.len();
+			if current_pending >= sender.queue_size_warning {
+				if sender.warning_fired == SenderWarningState::NotFired {
+					error!(
+						"The number of unprocessed events in channel `{}` exceeded {}.\n\
+						 The channel was created at:\n{:}\n
+						 The last event was sent from:\n{:}",
+						sender.name,
+						sender.queue_size_warning,
+						sender.creation_backtrace,
+						Backtrace::force_capture(),
+					);
+				} else if sender.warning_fired == SenderWarningState::FiredFree {
+					// We don't want to spam the logs, so we only log on debug level
+					debug!(
+						target: LOG_TARGET,
+						"Channel `{}` is overflowed again. Number of events: {}",
+						sender.name, current_pending
+					);
+				}
+				sender.warning_fired = SenderWarningState::FiredFull;
+			} else if sender.warning_fired == SenderWarningState::FiredFull &&
+				current_pending < sender.queue_size_warning.wrapping_div(2)
+			{
+				sender.warning_fired = SenderWarningState::FiredFree;
+				debug!(
+					target: LOG_TARGET,
+					"Channel `{}` is no longer overflowed. Number of events: {}",
+					sender.name, current_pending
+				);
+			}
+
+			sender.inner.try_send(event.clone()).is_ok()
+		});
+
+		if let Some(metrics) = &self.metrics {
+			for ev in &self.event_streams {
+				metrics.event_in(&event, ev.name);
+			}
+		}
+	}
+}
+
+impl fmt::Debug for OutChannels {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		f.debug_struct("OutChannels")
+			.field("num_channels", &self.event_streams.len())
+			.finish()
+	}
+}
+
+#[derive(Clone)]
+struct Metrics {
+	// This list is ordered alphabetically
+	events_total: CounterVec<U64>,
+	notifications_sizes: CounterVec<U64>,
+	num_channels: GaugeVec<U64>,
+}
+
+thread_local! {
+	static LABEL_BUFFER: RefCell<String> = RefCell::new(String::new());
+}
+
+fn format_label(prefix: &str, protocol: &str, callback: impl FnOnce(&str)) {
+	LABEL_BUFFER.with(|label_buffer| {
+		let mut label_buffer = label_buffer.borrow_mut();
+		label_buffer.clear();
+		label_buffer.reserve(prefix.len() + protocol.len() + 2);
+		label_buffer.push_str(prefix);
+		label_buffer.push('"');
+		label_buffer.push_str(protocol);
+		label_buffer.push('"');
+		callback(&label_buffer);
+	});
+}
+
+impl Metrics {
+	fn register(registry: &Registry) -> Result<Self, PrometheusError> {
+		Ok(Self {
+			events_total: register(CounterVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_out_events_events_total",
+					"Number of broadcast network events that have been sent or received across all \
+					 channels"
+				),
+				&["event_name", "action", "name"]
+			)?, registry)?,
+			notifications_sizes: register(CounterVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_out_events_notifications_sizes",
+					"Size of notification events that have been sent or received across all \
+					 channels"
+				),
+				&["protocol", "action", "name"]
+			)?, registry)?,
+			num_channels: register(GaugeVec::new(
+				Opts::new(
+					"bizinikiwi_sub_libp2p_out_events_num_channels",
+					"Number of internal active channels that broadcast network events",
+				),
+				&["name"]
+			)?, registry)?,
+		})
+	}
+
+	fn event_in(&self, event: &Event, name: &str) {
+		match event {
+			Event::Dht(_) => {
+				self.events_total.with_label_values(&["dht", "sent", name]).inc();
+			},
+			Event::NotificationStreamOpened { protocol, .. } => {
+				format_label("notif-open-", protocol, |protocol_label| {
+					self.events_total.with_label_values(&[protocol_label, "sent", name]).inc();
+				});
+			},
+			Event::NotificationStreamClosed { protocol, .. } => {
+				format_label("notif-closed-", protocol, |protocol_label| {
+					self.events_total.with_label_values(&[protocol_label, "sent", name]).inc();
+				});
+			},
+			Event::NotificationsReceived { messages, .. } =>
+				for (protocol, message) in messages {
+					format_label("notif-", protocol, |protocol_label| {
+						self.events_total.with_label_values(&[protocol_label, "sent", name]).inc();
+					});
+					self.notifications_sizes
+						.with_label_values(&[protocol, "sent", name])
+						.inc_by(u64::try_from(message.len()).unwrap_or(u64::MAX));
+				},
+		}
+	}
+
+	fn event_out(&self, event: &Event, name: &str) {
+		match event {
+			Event::Dht(_) => {
+				self.events_total.with_label_values(&["dht", "received", name]).inc();
+			},
+			Event::NotificationStreamOpened { protocol, .. } => {
+				format_label("notif-open-", protocol, |protocol_label| {
+					self.events_total.with_label_values(&[protocol_label, "received", name]).inc();
+				});
+			},
+			Event::NotificationStreamClosed { protocol, .. } => {
+				format_label("notif-closed-", protocol, |protocol_label| {
+					self.events_total.with_label_values(&[protocol_label, "received", name]).inc();
+				});
+			},
+			Event::NotificationsReceived { messages, .. } =>
+				for (protocol, message) in messages {
+					format_label("notif-", protocol, |protocol_label| {
+						self.events_total
+							.with_label_values(&[protocol_label, "received", name])
+							.inc();
+					});
+					self.notifications_sizes
+						.with_label_values(&[protocol, "received", name])
+						.inc_by(u64::try_from(message.len()).unwrap_or(u64::MAX));
+				},
+		}
+	}
+}

bizinikiwi/client/network/src/service/signature.rs

@@ -0,0 +1,113 @@
+// This file is part of Bizinikiwi.
+//
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+//
+// If you read this, you are very thorough, congratulations.
+
+//! Signature-related code
+
+pub use libp2p::identity::SigningError;
+
+/// Public key.
+pub enum PublicKey {
+	/// Litep2p public key.
+	Libp2p(libp2p::identity::PublicKey),
+
+	/// Libp2p public key.
+	Litep2p(litep2p::crypto::PublicKey),
+}
+
+impl PublicKey {
+	/// Protobuf-encode [`PublicKey`].
+	pub fn encode_protobuf(&self) -> Vec<u8> {
+		match self {
+			Self::Libp2p(public) => public.encode_protobuf(),
+			Self::Litep2p(public) => public.to_protobuf_encoding(),
+		}
+	}
+
+	/// Get `PeerId` of the [`PublicKey`].
+	pub fn to_peer_id(&self) -> pezsc_network_types::PeerId {
+		match self {
+			Self::Libp2p(public) => public.to_peer_id().into(),
+			Self::Litep2p(public) => public.to_peer_id().into(),
+		}
+	}
+}
+
+/// Keypair.
+pub enum Keypair {
+	/// Litep2p keypair.
+	Libp2p(libp2p::identity::Keypair),
+
+	/// Libp2p keypair.
+	Litep2p(litep2p::crypto::ed25519::Keypair),
+}
+
+impl Keypair {
+	/// Generate ed25519 keypair.
+	pub fn generate_ed25519() -> Self {
+		Keypair::Litep2p(litep2p::crypto::ed25519::Keypair::generate())
+	}
+
+	/// Get [`Keypair`]'s public key.
+	pub fn public(&self) -> PublicKey {
+		match self {
+			Keypair::Libp2p(keypair) => PublicKey::Libp2p(keypair.public()),
+			Keypair::Litep2p(keypair) => PublicKey::Litep2p(keypair.public().into()),
+		}
+	}
+}
+
+/// A result of signing a message with a network identity. Since `PeerId` is potentially a hash of a
+/// `PublicKey`, you need to reveal the `PublicKey` next to the signature, so the verifier can check
+/// if the signature was made by the entity that controls a given `PeerId`.
+pub struct Signature {
+	/// The public key derived from the network identity that signed the message.
+	pub public_key: PublicKey,
+
+	/// The actual signature made for the message signed.
+	pub bytes: Vec<u8>,
+}
+
+impl Signature {
+	/// Create new [`Signature`].
+	pub fn new(public_key: PublicKey, bytes: Vec<u8>) -> Self {
+		Self { public_key, bytes }
+	}
+
+	/// Create a signature for a message with a given network identity.
+	pub fn sign_message(
+		message: impl AsRef<[u8]>,
+		keypair: &Keypair,
+	) -> Result<Self, SigningError> {
+		match keypair {
+			Keypair::Libp2p(keypair) => {
+				let public_key = keypair.public();
+				let bytes = keypair.sign(message.as_ref())?;
+
+				Ok(Signature { public_key: PublicKey::Libp2p(public_key), bytes })
+			},
+			Keypair::Litep2p(keypair) => {
+				let public_key = keypair.public();
+				let bytes = keypair.sign(message.as_ref());
+
+				Ok(Signature { public_key: PublicKey::Litep2p(public_key.into()), bytes })
+			},
+		}
+	}
+}

bizinikiwi/client/network/src/service/traits.rs

@@ -0,0 +1,972 @@
+// This file is part of Bizinikiwi.
+//
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+//
+// If you read this, you are very thorough, congratulations.
+
+//! Traits defined by `sc-network`.
+
+use crate::{
+	config::{IncomingRequest, MultiaddrWithPeerId, NotificationHandshake, Params, SetConfig},
+	error::{self, Error},
+	event::Event,
+	network_state::NetworkState,
+	request_responses::{IfDisconnected, RequestFailure},
+	service::{metrics::NotificationMetrics, signature::Signature, PeerStoreProvider},
+	types::ProtocolName,
+	ReputationChange,
+};
+
+use futures::{channel::oneshot, Stream};
+use prometheus_endpoint::Registry;
+
+use pezsc_client_api::BlockBackend;
+use pezsc_network_common::{role::ObservedRole, ExHashT};
+pub use pezsc_network_types::{
+	kad::{Key as KademliaKey, Record},
+	multiaddr::Multiaddr,
+	PeerId,
+};
+use pezsp_runtime::traits::Block as BlockT;
+
+use std::{
+	collections::HashSet,
+	fmt::Debug,
+	future::Future,
+	pin::Pin,
+	sync::Arc,
+	time::{Duration, Instant},
+};
+
+pub use libp2p::identity::SigningError;
+
+/// Supertrait defining the services provided by [`NetworkBackend`] service handle.
+pub trait NetworkService:
+	NetworkSigner
+	+ NetworkDHTProvider
+	+ NetworkStatusProvider
+	+ NetworkPeers
+	+ NetworkEventStream
+	+ NetworkStateInfo
+	+ NetworkRequest
+	+ Send
+	+ Sync
+	+ 'static
+{
+}
+
+impl<T> NetworkService for T where
+	T: NetworkSigner
+		+ NetworkDHTProvider
+		+ NetworkStatusProvider
+		+ NetworkPeers
+		+ NetworkEventStream
+		+ NetworkStateInfo
+		+ NetworkRequest
+		+ Send
+		+ Sync
+		+ 'static
+{
+}
+
+/// Trait defining the required functionality from a notification protocol configuration.
+pub trait NotificationConfig: Debug {
+	/// Get access to the `SetConfig` of the notification protocol.
+	fn set_config(&self) -> &SetConfig;
+
+	/// Get protocol name.
+	fn protocol_name(&self) -> &ProtocolName;
+}
+
+/// Trait defining the required functionality from a request-response protocol configuration.
+pub trait RequestResponseConfig: Debug {
+	/// Get protocol name.
+	fn protocol_name(&self) -> &ProtocolName;
+}
+
+/// Trait defining required functionality from `PeerStore`.
+#[async_trait::async_trait]
+pub trait PeerStore {
+	/// Get handle to `PeerStore`.
+	fn handle(&self) -> Arc<dyn PeerStoreProvider>;
+
+	/// Start running `PeerStore` event loop.
+	async fn run(self);
+}
+
+/// Networking backend.
+#[async_trait::async_trait]
+pub trait NetworkBackend<B: BlockT + 'static, H: ExHashT>: Send + 'static {
+	/// Type representing notification protocol-related configuration.
+	type NotificationProtocolConfig: NotificationConfig;
+
+	/// Type representing request-response protocol-related configuration.
+	type RequestResponseProtocolConfig: RequestResponseConfig;
+
+	/// Type implementing `NetworkService` for the networking backend.
+	///
+	/// `NetworkService` allows other subsystems of the blockchain to interact with `sc-network`
+	/// using `NetworkService`.
+	type NetworkService<Block, Hash>: NetworkService + Clone;
+
+	/// Type implementing [`PeerStore`].
+	type PeerStore: PeerStore;
+
+	/// Bitswap config.
+	type BitswapConfig;
+
+	/// Create new `NetworkBackend`.
+	fn new(params: Params<B, H, Self>) -> Result<Self, Error>
+	where
+		Self: Sized;
+
+	/// Get handle to `NetworkService` of the `NetworkBackend`.
+	fn network_service(&self) -> Arc<dyn NetworkService>;
+
+	/// Create [`PeerStore`].
+	fn peer_store(bootnodes: Vec<PeerId>, metrics_registry: Option<Registry>) -> Self::PeerStore;
+
+	/// Register metrics that are used by the notification protocols.
+	fn register_notification_metrics(registry: Option<&Registry>) -> NotificationMetrics;
+
+	/// Create Bitswap server.
+	fn bitswap_server(
+		client: Arc<dyn BlockBackend<B> + Send + Sync>,
+	) -> (Pin<Box<dyn Future<Output = ()> + Send>>, Self::BitswapConfig);
+
+	/// Create notification protocol configuration and an associated `NotificationService`
+	/// for the protocol.
+	fn notification_config(
+		protocol_name: ProtocolName,
+		fallback_names: Vec<ProtocolName>,
+		max_notification_size: u64,
+		handshake: Option<NotificationHandshake>,
+		set_config: SetConfig,
+		metrics: NotificationMetrics,
+		peerstore_handle: Arc<dyn PeerStoreProvider>,
+	) -> (Self::NotificationProtocolConfig, Box<dyn NotificationService>);
+
+	/// Create request-response protocol configuration.
+	fn request_response_config(
+		protocol_name: ProtocolName,
+		fallback_names: Vec<ProtocolName>,
+		max_request_size: u64,
+		max_response_size: u64,
+		request_timeout: Duration,
+		inbound_queue: Option<async_channel::Sender<IncomingRequest>>,
+	) -> Self::RequestResponseProtocolConfig;
+
+	/// Start [`NetworkBackend`] event loop.
+	async fn run(mut self);
+}
+
+/// Signer with network identity
+pub trait NetworkSigner {
+	/// Signs the message with the `KeyPair` that defines the local [`PeerId`].
+	fn sign_with_local_identity(&self, msg: Vec<u8>) -> Result<Signature, SigningError>;
+
+	/// Verify signature using peer's public key.
+	///
+	/// `public_key` must be Protobuf-encoded ed25519 public key.
+	///
+	/// Returns `Err(())` if public cannot be parsed into a valid ed25519 public key.
+	fn verify(
+		&self,
+		peer_id: pezsc_network_types::PeerId,
+		public_key: &Vec<u8>,
+		signature: &Vec<u8>,
+		message: &Vec<u8>,
+	) -> Result<bool, String>;
+}
+
+impl<T> NetworkSigner for Arc<T>
+where
+	T: ?Sized,
+	T: NetworkSigner,
+{
+	fn sign_with_local_identity(&self, msg: Vec<u8>) -> Result<Signature, SigningError> {
+		T::sign_with_local_identity(self, msg)
+	}
+
+	fn verify(
+		&self,
+		peer_id: pezsc_network_types::PeerId,
+		public_key: &Vec<u8>,
+		signature: &Vec<u8>,
+		message: &Vec<u8>,
+	) -> Result<bool, String> {
+		T::verify(self, peer_id, public_key, signature, message)
+	}
+}
+
+/// Provides access to the networking DHT.
+pub trait NetworkDHTProvider {
+	/// Start finding closest peers to the target.
+	fn find_closest_peers(&self, target: PeerId);
+
+	/// Start getting a value from the DHT.
+	fn get_value(&self, key: &KademliaKey);
+
+	/// Start putting a value in the DHT.
+	fn put_value(&self, key: KademliaKey, value: Vec<u8>);
+
+	/// Start putting the record to `peers`.
+	///
+	/// If `update_local_storage` is true the local storage is udpated as well.
+	fn put_record_to(&self, record: Record, peers: HashSet<PeerId>, update_local_storage: bool);
+
+	/// Store a record in the DHT memory store.
+	fn store_record(
+		&self,
+		key: KademliaKey,
+		value: Vec<u8>,
+		publisher: Option<PeerId>,
+		expires: Option<Instant>,
+	);
+
+	/// Register this node as a provider for `key` on the DHT.
+	fn start_providing(&self, key: KademliaKey);
+
+	/// Deregister this node as a provider for `key` on the DHT.
+	fn stop_providing(&self, key: KademliaKey);
+
+	/// Start getting the list of providers for `key` on the DHT.
+	fn get_providers(&self, key: KademliaKey);
+}
+
+impl<T> NetworkDHTProvider for Arc<T>
+where
+	T: ?Sized,
+	T: NetworkDHTProvider,
+{
+	fn find_closest_peers(&self, target: PeerId) {
+		T::find_closest_peers(self, target)
+	}
+
+	fn get_value(&self, key: &KademliaKey) {
+		T::get_value(self, key)
+	}
+
+	fn put_value(&self, key: KademliaKey, value: Vec<u8>) {
+		T::put_value(self, key, value)
+	}
+
+	fn put_record_to(&self, record: Record, peers: HashSet<PeerId>, update_local_storage: bool) {
+		T::put_record_to(self, record, peers, update_local_storage)
+	}
+
+	fn store_record(
+		&self,
+		key: KademliaKey,
+		value: Vec<u8>,
+		publisher: Option<PeerId>,
+		expires: Option<Instant>,
+	) {
+		T::store_record(self, key, value, publisher, expires)
+	}
+
+	fn start_providing(&self, key: KademliaKey) {
+		T::start_providing(self, key)
+	}
+
+	fn stop_providing(&self, key: KademliaKey) {
+		T::stop_providing(self, key)
+	}
+
+	fn get_providers(&self, key: KademliaKey) {
+		T::get_providers(self, key)
+	}
+}
+
+/// Provides an ability to set a fork sync request for a particular block.
+pub trait NetworkSyncForkRequest<BlockHash, BlockNumber> {
+	/// Notifies the sync service to try and sync the given block from the given
+	/// peers.
+	///
+	/// If the given vector of peers is empty then the underlying implementation
+	/// should make a best effort to fetch the block from any peers it is
+	/// connected to (NOTE: this assumption will change in the future #3629).
+	fn set_sync_fork_request(&self, peers: Vec<PeerId>, hash: BlockHash, number: BlockNumber);
+}
+
+impl<T, BlockHash, BlockNumber> NetworkSyncForkRequest<BlockHash, BlockNumber> for Arc<T>
+where
+	T: ?Sized,
+	T: NetworkSyncForkRequest<BlockHash, BlockNumber>,
+{
+	fn set_sync_fork_request(&self, peers: Vec<PeerId>, hash: BlockHash, number: BlockNumber) {
+		T::set_sync_fork_request(self, peers, hash, number)
+	}
+}
+
+/// Overview status of the network.
+#[derive(Clone)]
+pub struct NetworkStatus {
+	/// Total number of connected peers.
+	pub num_connected_peers: usize,
+	/// The total number of bytes received.
+	pub total_bytes_inbound: u64,
+	/// The total number of bytes sent.
+	pub total_bytes_outbound: u64,
+}
+
+/// Provides high-level status information about network.
+#[async_trait::async_trait]
+pub trait NetworkStatusProvider {
+	/// High-level network status information.
+	///
+	/// Returns an error if the `NetworkWorker` is no longer running.
+	async fn status(&self) -> Result<NetworkStatus, ()>;
+
+	/// Get the network state.
+	///
+	/// Returns an error if the `NetworkWorker` is no longer running.
+	async fn network_state(&self) -> Result<NetworkState, ()>;
+}
+
+// Manual implementation to avoid extra boxing here
+impl<T> NetworkStatusProvider for Arc<T>
+where
+	T: ?Sized,
+	T: NetworkStatusProvider,
+{
+	fn status<'life0, 'async_trait>(
+		&'life0 self,
+	) -> Pin<Box<dyn Future<Output = Result<NetworkStatus, ()>> + Send + 'async_trait>>
+	where
+		'life0: 'async_trait,
+		Self: 'async_trait,
+	{
+		T::status(self)
+	}
+
+	fn network_state<'life0, 'async_trait>(
+		&'life0 self,
+	) -> Pin<Box<dyn Future<Output = Result<NetworkState, ()>> + Send + 'async_trait>>
+	where
+		'life0: 'async_trait,
+		Self: 'async_trait,
+	{
+		T::network_state(self)
+	}
+}
+
+/// Provides low-level API for manipulating network peers.
+#[async_trait::async_trait]
+pub trait NetworkPeers {
+	/// Set authorized peers.
+	///
+	/// Need a better solution to manage authorized peers, but now just use reserved peers for
+	/// prototyping.
+	fn set_authorized_peers(&self, peers: HashSet<PeerId>);
+
+	/// Set authorized_only flag.
+	///
+	/// Need a better solution to decide authorized_only, but now just use reserved_only flag for
+	/// prototyping.
+	fn set_authorized_only(&self, reserved_only: bool);
+
+	/// Adds an address known to a node.
+	fn add_known_address(&self, peer_id: PeerId, addr: Multiaddr);
+
+	/// Report a given peer as either beneficial (+) or costly (-) according to the
+	/// given scalar.
+	fn report_peer(&self, peer_id: PeerId, cost_benefit: ReputationChange);
+
+	/// Get peer reputation.
+	fn peer_reputation(&self, peer_id: &PeerId) -> i32;
+
+	/// Disconnect from a node as soon as possible.
+	///
+	/// This triggers the same effects as if the connection had closed itself spontaneously.
+	fn disconnect_peer(&self, peer_id: PeerId, protocol: ProtocolName);
+
+	/// Connect to unreserved peers and allow unreserved peers to connect for syncing purposes.
+	fn accept_unreserved_peers(&self);
+
+	/// Disconnect from unreserved peers and deny new unreserved peers to connect for syncing
+	/// purposes.
+	fn deny_unreserved_peers(&self);
+
+	/// Adds a `PeerId` and its `Multiaddr` as reserved for a sync protocol (default peer set).
+	///
+	/// Returns an `Err` if the given string is not a valid multiaddress
+	/// or contains an invalid peer ID (which includes the local peer ID).
+	fn add_reserved_peer(&self, peer: MultiaddrWithPeerId) -> Result<(), String>;
+
+	/// Removes a `PeerId` from the list of reserved peers for a sync protocol (default peer set).
+	fn remove_reserved_peer(&self, peer_id: PeerId);
+
+	/// Sets the reserved set of a protocol to the given set of peers.
+	///
+	/// Each `Multiaddr` must end with a `/p2p/` component containing the `PeerId`. It can also
+	/// consist of only `/p2p/<peerid>`.
+	///
+	/// The node will start establishing/accepting connections and substreams to/from peers in this
+	/// set, if it doesn't have any substream open with them yet.
+	///
+	/// Note however, if a call to this function results in less peers on the reserved set, they
+	/// will not necessarily get disconnected (depending on available free slots in the peer set).
+	/// If you want to also disconnect those removed peers, you will have to call
+	/// `remove_from_peers_set` on those in addition to updating the reserved set. You can omit
+	/// this step if the peer set is in reserved only mode.
+	///
+	/// Returns an `Err` if one of the given addresses is invalid or contains an
+	/// invalid peer ID (which includes the local peer ID), or if `protocol` does not
+	/// refer to a known protocol.
+	fn set_reserved_peers(
+		&self,
+		protocol: ProtocolName,
+		peers: HashSet<Multiaddr>,
+	) -> Result<(), String>;
+
+	/// Add peers to a peer set.
+	///
+	/// Each `Multiaddr` must end with a `/p2p/` component containing the `PeerId`. It can also
+	/// consist of only `/p2p/<peerid>`.
+	///
+	/// Returns an `Err` if one of the given addresses is invalid or contains an
+	/// invalid peer ID (which includes the local peer ID), or if `protocol` does not
+	/// refer to a know protocol.
+	fn add_peers_to_reserved_set(
+		&self,
+		protocol: ProtocolName,
+		peers: HashSet<Multiaddr>,
+	) -> Result<(), String>;
+
+	/// Remove peers from a peer set.
+	///
+	/// Returns `Err` if `protocol` does not refer to a known protocol.
+	fn remove_peers_from_reserved_set(
+		&self,
+		protocol: ProtocolName,
+		peers: Vec<PeerId>,
+	) -> Result<(), String>;
+
+	/// Returns the number of peers in the sync peer set we're connected to.
+	fn sync_num_connected(&self) -> usize;
+
+	/// Attempt to get peer role.
+	///
+	/// Right now the peer role is decoded from the received handshake for all protocols
+	/// (`/block-announces/1` has other information as well). If the handshake cannot be
+	/// decoded into a role, the role queried from `PeerStore` and if the role is not stored
+	/// there either, `None` is returned and the peer should be discarded.
+	fn peer_role(&self, peer_id: PeerId, handshake: Vec<u8>) -> Option<ObservedRole>;
+
+	/// Get the list of reserved peers.
+	///
+	/// Returns an error if the `NetworkWorker` is no longer running.
+	async fn reserved_peers(&self) -> Result<Vec<PeerId>, ()>;
+}
+
+// Manual implementation to avoid extra boxing here
+#[async_trait::async_trait]
+impl<T> NetworkPeers for Arc<T>
+where
+	T: ?Sized,
+	T: NetworkPeers,
+{
+	fn set_authorized_peers(&self, peers: HashSet<PeerId>) {
+		T::set_authorized_peers(self, peers)
+	}
+
+	fn set_authorized_only(&self, reserved_only: bool) {
+		T::set_authorized_only(self, reserved_only)
+	}
+
+	fn add_known_address(&self, peer_id: PeerId, addr: Multiaddr) {
+		T::add_known_address(self, peer_id, addr)
+	}
+
+	fn report_peer(&self, peer_id: PeerId, cost_benefit: ReputationChange) {
+		T::report_peer(self, peer_id, cost_benefit)
+	}
+
+	fn peer_reputation(&self, peer_id: &PeerId) -> i32 {
+		T::peer_reputation(self, peer_id)
+	}
+
+	fn disconnect_peer(&self, peer_id: PeerId, protocol: ProtocolName) {
+		T::disconnect_peer(self, peer_id, protocol)
+	}
+
+	fn accept_unreserved_peers(&self) {
+		T::accept_unreserved_peers(self)
+	}
+
+	fn deny_unreserved_peers(&self) {
+		T::deny_unreserved_peers(self)
+	}
+
+	fn add_reserved_peer(&self, peer: MultiaddrWithPeerId) -> Result<(), String> {
+		T::add_reserved_peer(self, peer)
+	}
+
+	fn remove_reserved_peer(&self, peer_id: PeerId) {
+		T::remove_reserved_peer(self, peer_id)
+	}
+
+	fn set_reserved_peers(
+		&self,
+		protocol: ProtocolName,
+		peers: HashSet<Multiaddr>,
+	) -> Result<(), String> {
+		T::set_reserved_peers(self, protocol, peers)
+	}
+
+	fn add_peers_to_reserved_set(
+		&self,
+		protocol: ProtocolName,
+		peers: HashSet<Multiaddr>,
+	) -> Result<(), String> {
+		T::add_peers_to_reserved_set(self, protocol, peers)
+	}
+
+	fn remove_peers_from_reserved_set(
+		&self,
+		protocol: ProtocolName,
+		peers: Vec<PeerId>,
+	) -> Result<(), String> {
+		T::remove_peers_from_reserved_set(self, protocol, peers)
+	}
+
+	fn sync_num_connected(&self) -> usize {
+		T::sync_num_connected(self)
+	}
+
+	fn peer_role(&self, peer_id: PeerId, handshake: Vec<u8>) -> Option<ObservedRole> {
+		T::peer_role(self, peer_id, handshake)
+	}
+
+	fn reserved_peers<'life0, 'async_trait>(
+		&'life0 self,
+	) -> Pin<Box<dyn Future<Output = Result<Vec<PeerId>, ()>> + Send + 'async_trait>>
+	where
+		'life0: 'async_trait,
+		Self: 'async_trait,
+	{
+		T::reserved_peers(self)
+	}
+}
+
+/// Provides access to network-level event stream.
+pub trait NetworkEventStream {
+	/// Returns a stream containing the events that happen on the network.
+	///
+	/// If this method is called multiple times, the events are duplicated.
+	///
+	/// The stream never ends (unless the `NetworkWorker` gets shut down).
+	///
+	/// The name passed is used to identify the channel in the Prometheus metrics. Note that the
+	/// parameter is a `&'static str`, and not a `String`, in order to avoid accidentally having
+	/// an unbounded set of Prometheus metrics, which would be quite bad in terms of memory
+	fn event_stream(&self, name: &'static str) -> Pin<Box<dyn Stream<Item = Event> + Send>>;
+}
+
+impl<T> NetworkEventStream for Arc<T>
+where
+	T: ?Sized,
+	T: NetworkEventStream,
+{
+	fn event_stream(&self, name: &'static str) -> Pin<Box<dyn Stream<Item = Event> + Send>> {
+		T::event_stream(self, name)
+	}
+}
+
+/// Trait for providing information about the local network state
+pub trait NetworkStateInfo {
+	/// Returns the local external addresses.
+	fn external_addresses(&self) -> Vec<Multiaddr>;
+
+	/// Returns the listening addresses (without trailing `/p2p/` with our `PeerId`).
+	fn listen_addresses(&self) -> Vec<Multiaddr>;
+
+	/// Returns the local Peer ID.
+	fn local_peer_id(&self) -> PeerId;
+}
+
+impl<T> NetworkStateInfo for Arc<T>
+where
+	T: ?Sized,
+	T: NetworkStateInfo,
+{
+	fn external_addresses(&self) -> Vec<Multiaddr> {
+		T::external_addresses(self)
+	}
+
+	fn listen_addresses(&self) -> Vec<Multiaddr> {
+		T::listen_addresses(self)
+	}
+
+	fn local_peer_id(&self) -> PeerId {
+		T::local_peer_id(self)
+	}
+}
+
+/// Reserved slot in the notifications buffer, ready to accept data.
+pub trait NotificationSenderReady {
+	/// Consumes this slots reservation and actually queues the notification.
+	///
+	/// NOTE: Traits can't consume itself, but calling this method second time will return an error.
+	fn send(&mut self, notification: Vec<u8>) -> Result<(), NotificationSenderError>;
+}
+
+/// A `NotificationSender` allows for sending notifications to a peer with a chosen protocol.
+#[async_trait::async_trait]
+pub trait NotificationSender: Send + Sync + 'static {
+	/// Returns a future that resolves when the `NotificationSender` is ready to send a
+	/// notification.
+	async fn ready(&self)
+		-> Result<Box<dyn NotificationSenderReady + '_>, NotificationSenderError>;
+}
+
+/// Error returned by the notification sink.
+#[derive(Debug, thiserror::Error)]
+pub enum NotificationSenderError {
+	/// The notification receiver has been closed, usually because the underlying connection
+	/// closed.
+	///
+	/// Some of the notifications most recently sent may not have been received. However,
+	/// the peer may still be connected and a new notification sink for the same
+	/// protocol obtained from [`NotificationService::message_sink()`].
+	#[error("The notification receiver has been closed")]
+	Closed,
+	/// Protocol name hasn't been registered.
+	#[error("Protocol name hasn't been registered")]
+	BadProtocol,
+}
+
+/// Provides ability to send network requests.
+#[async_trait::async_trait]
+pub trait NetworkRequest {
+	/// Sends a single targeted request to a specific peer. On success, returns the response of
+	/// the peer.
+	///
+	/// Request-response protocols are a way to complement notifications protocols, but
+	/// notifications should remain the default ways of communicating information. For example, a
+	/// peer can announce something through a notification, after which the recipient can obtain
+	/// more information by performing a request.
+	/// As such, call this function with `IfDisconnected::ImmediateError` for `connect`. This way
+	/// you will get an error immediately for disconnected peers, instead of waiting for a
+	/// potentially very long connection attempt, which would suggest that something is wrong
+	/// anyway, as you are supposed to be connected because of the notification protocol.
+	///
+	/// No limit or throttling of concurrent outbound requests per peer and protocol are enforced.
+	/// Such restrictions, if desired, need to be enforced at the call site(s).
+	///
+	/// The protocol must have been registered through
+	/// `NetworkConfiguration::request_response_protocols`.
+	async fn request(
+		&self,
+		target: PeerId,
+		protocol: ProtocolName,
+		request: Vec<u8>,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+		connect: IfDisconnected,
+	) -> Result<(Vec<u8>, ProtocolName), RequestFailure>;
+
+	/// Variation of `request` which starts a request whose response is delivered on a provided
+	/// channel.
+	///
+	/// Instead of blocking and waiting for a reply, this function returns immediately, sending
+	/// responses via the passed in sender. This alternative API exists to make it easier to
+	/// integrate with message passing APIs.
+	///
+	/// Keep in mind that the connected receiver might receive a `Canceled` event in case of a
+	/// closing connection. This is expected behaviour. With `request` you would get a
+	/// `RequestFailure::Network(OutboundFailure::ConnectionClosed)` in that case.
+	fn start_request(
+		&self,
+		target: PeerId,
+		protocol: ProtocolName,
+		request: Vec<u8>,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+		tx: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+		connect: IfDisconnected,
+	);
+}
+
+// Manual implementation to avoid extra boxing here
+impl<T> NetworkRequest for Arc<T>
+where
+	T: ?Sized,
+	T: NetworkRequest,
+{
+	fn request<'life0, 'async_trait>(
+		&'life0 self,
+		target: PeerId,
+		protocol: ProtocolName,
+		request: Vec<u8>,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+		connect: IfDisconnected,
+	) -> Pin<
+		Box<
+			dyn Future<Output = Result<(Vec<u8>, ProtocolName), RequestFailure>>
+				+ Send
+				+ 'async_trait,
+		>,
+	>
+	where
+		'life0: 'async_trait,
+		Self: 'async_trait,
+	{
+		T::request(self, target, protocol, request, fallback_request, connect)
+	}
+
+	fn start_request(
+		&self,
+		target: PeerId,
+		protocol: ProtocolName,
+		request: Vec<u8>,
+		fallback_request: Option<(Vec<u8>, ProtocolName)>,
+		tx: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+		connect: IfDisconnected,
+	) {
+		T::start_request(self, target, protocol, request, fallback_request, tx, connect)
+	}
+}
+
+/// Provides ability to announce blocks to the network.
+pub trait NetworkBlock<BlockHash, BlockNumber> {
+	/// Make sure an important block is propagated to peers.
+	///
+	/// In chain-based consensus, we often need to make sure non-best forks are
+	/// at least temporarily synced. This function forces such an announcement.
+	fn announce_block(&self, hash: BlockHash, data: Option<Vec<u8>>);
+
+	/// Inform the network service about new best imported block.
+	fn new_best_block_imported(&self, hash: BlockHash, number: BlockNumber);
+}
+
+impl<T, BlockHash, BlockNumber> NetworkBlock<BlockHash, BlockNumber> for Arc<T>
+where
+	T: ?Sized,
+	T: NetworkBlock<BlockHash, BlockNumber>,
+{
+	fn announce_block(&self, hash: BlockHash, data: Option<Vec<u8>>) {
+		T::announce_block(self, hash, data)
+	}
+
+	fn new_best_block_imported(&self, hash: BlockHash, number: BlockNumber) {
+		T::new_best_block_imported(self, hash, number)
+	}
+}
+
+/// Substream acceptance result.
+#[derive(Debug, PartialEq, Eq)]
+pub enum ValidationResult {
+	/// Accept inbound substream.
+	Accept,
+
+	/// Reject inbound substream.
+	Reject,
+}
+
+/// Substream direction.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum Direction {
+	/// Substream opened by the remote node.
+	Inbound,
+
+	/// Substream opened by the local node.
+	Outbound,
+}
+
+impl From<litep2p::protocol::notification::Direction> for Direction {
+	fn from(direction: litep2p::protocol::notification::Direction) -> Self {
+		match direction {
+			litep2p::protocol::notification::Direction::Inbound => Direction::Inbound,
+			litep2p::protocol::notification::Direction::Outbound => Direction::Outbound,
+		}
+	}
+}
+
+impl Direction {
+	/// Is the direction inbound.
+	pub fn is_inbound(&self) -> bool {
+		std::matches!(self, Direction::Inbound)
+	}
+}
+
+/// Events received by the protocol from `Notifications`.
+#[derive(Debug)]
+pub enum NotificationEvent {
+	/// Validate inbound substream.
+	ValidateInboundSubstream {
+		/// Peer ID.
+		peer: PeerId,
+
+		/// Received handshake.
+		handshake: Vec<u8>,
+
+		/// `oneshot::Sender` for sending validation result back to `Notifications`
+		result_tx: tokio::sync::oneshot::Sender<ValidationResult>,
+	},
+
+	/// Remote identified by `PeerId` opened a substream and sent `Handshake`.
+	/// Validate `Handshake` and report status (accept/reject) to `Notifications`.
+	NotificationStreamOpened {
+		/// Peer ID.
+		peer: PeerId,
+
+		/// Is the substream inbound or outbound.
+		direction: Direction,
+
+		/// Received handshake.
+		handshake: Vec<u8>,
+
+		/// Negotiated fallback.
+		negotiated_fallback: Option<ProtocolName>,
+	},
+
+	/// Substream was closed.
+	NotificationStreamClosed {
+		/// Peer Id.
+		peer: PeerId,
+	},
+
+	/// Notification was received from the substream.
+	NotificationReceived {
+		/// Peer ID.
+		peer: PeerId,
+
+		/// Received notification.
+		notification: Vec<u8>,
+	},
+}
+
+/// Notification service
+///
+/// Defines behaviors that both the protocol implementations and `Notifications` can expect from
+/// each other.
+///
+/// `Notifications` can send two different kinds of information to protocol:
+///  * substream-related information
+///  * notification-related information
+///
+/// When an unvalidated, inbound substream is received by `Notifications`, it sends the inbound
+/// stream information (peer ID, handshake) to protocol for validation. Protocol must then verify
+/// that the handshake is valid (and in the future that it has a slot it can allocate for the peer)
+/// and then report back the `ValidationResult` which is either `Accept` or `Reject`.
+///
+/// After the validation result has been received by `Notifications`, it prepares the
+/// substream for communication by initializing the necessary sinks and emits
+/// `NotificationStreamOpened` which informs the protocol that the remote peer is ready to receive
+/// notifications.
+///
+/// Two different flavors of sending options are provided:
+///  * synchronous sending ([`NotificationService::send_sync_notification()`])
+///  * asynchronous sending ([`NotificationService::send_async_notification()`])
+///
+/// The former is used by the protocols not ready to exercise backpressure and the latter by the
+/// protocols that can do it.
+///
+/// Both local and remote peer can close the substream at any time. Local peer can do so by calling
+/// [`NotificationService::close_substream()`] which instructs `Notifications` to close the
+/// substream. Remote closing the substream is indicated to the local peer by receiving
+/// [`NotificationEvent::NotificationStreamClosed`] event.
+///
+/// In case the protocol must update its handshake while it's operating (such as updating the best
+/// block information), it can do so by calling [`NotificationService::set_handshake()`]
+/// which instructs `Notifications` to update the handshake it stored during protocol
+/// initialization.
+///
+/// All peer events are multiplexed on the same incoming event stream from `Notifications` and thus
+/// each event carries a `PeerId` so the protocol knows whose information to update when receiving
+/// an event.
+#[async_trait::async_trait]
+pub trait NotificationService: Debug + Send {
+	/// Instruct `Notifications` to open a new substream for `peer`.
+	///
+	/// `dial_if_disconnected` informs `Notifications` whether to dial
+	// the peer if there is currently no active connection to it.
+	//
+	// NOTE: not offered by the current implementation
+	async fn open_substream(&mut self, peer: PeerId) -> Result<(), ()>;
+
+	/// Instruct `Notifications` to close substream for `peer`.
+	//
+	// NOTE: not offered by the current implementation
+	async fn close_substream(&mut self, peer: PeerId) -> Result<(), ()>;
+
+	/// Send synchronous `notification` to `peer`.
+	fn send_sync_notification(&mut self, peer: &PeerId, notification: Vec<u8>);
+
+	/// Send asynchronous `notification` to `peer`, allowing sender to exercise backpressure.
+	///
+	/// Returns an error if the peer doesn't exist.
+	async fn send_async_notification(
+		&mut self,
+		peer: &PeerId,
+		notification: Vec<u8>,
+	) -> Result<(), error::Error>;
+
+	/// Set handshake for the notification protocol replacing the old handshake.
+	async fn set_handshake(&mut self, handshake: Vec<u8>) -> Result<(), ()>;
+
+	/// Non-blocking variant of `set_handshake()` that attempts to update the handshake
+	/// and returns an error if the channel is blocked.
+	///
+	/// Technically the function can return an error if the channel to `Notifications` is closed
+	/// but that doesn't happen under normal operation.
+	fn try_set_handshake(&mut self, handshake: Vec<u8>) -> Result<(), ()>;
+
+	/// Get next event from the `Notifications` event stream.
+	async fn next_event(&mut self) -> Option<NotificationEvent>;
+
+	/// Make a copy of the object so it can be shared between protocol components
+	/// who wish to have access to the same underlying notification protocol.
+	fn clone(&mut self) -> Result<Box<dyn NotificationService>, ()>;
+
+	/// Get protocol name of the `NotificationService`.
+	fn protocol(&self) -> &ProtocolName;
+
+	/// Get message sink of the peer.
+	fn message_sink(&self, peer: &PeerId) -> Option<Box<dyn MessageSink>>;
+}
+
+/// Message sink for peers.
+///
+/// If protocol cannot use [`NotificationService`] to send notifications to peers and requires,
+/// e.g., notifications to be sent in another task, the protocol may acquire a [`MessageSink`]
+/// object for each peer by calling [`NotificationService::message_sink()`]. Calling this
+/// function returns an object which allows the protocol to send notifications to the remote peer.
+///
+/// Use of this API is discouraged as it's not as performant as sending notifications through
+/// [`NotificationService`] due to synchronization required to keep the underlying notification
+/// sink up to date with possible sink replacement events.
+#[async_trait::async_trait]
+pub trait MessageSink: Send + Sync {
+	/// Send synchronous `notification` to the peer associated with this [`MessageSink`].
+	fn send_sync_notification(&self, notification: Vec<u8>);
+
+	/// Send an asynchronous `notification` to to the peer associated with this [`MessageSink`],
+	/// allowing sender to exercise backpressure.
+	///
+	/// Returns an error if the peer does not exist.
+	async fn send_async_notification(&self, notification: Vec<u8>) -> Result<(), error::Error>;
+}
+
+/// Trait defining the behavior of a bandwidth sink.
+pub trait BandwidthSink: Send + Sync {
+	/// Get the number of bytes received.
+	fn total_inbound(&self) -> u64;
+
+	/// Get the number of bytes sent.
+	fn total_outbound(&self) -> u64;
+}

bizinikiwi/client/network/src/transport.rs

@@ -0,0 +1,87 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Transport that serves as a common ground for all connections.
+
+use either::Either;
+use libp2p::{
+	core::{
+		muxing::StreamMuxerBox,
+		transport::{Boxed, OptionalTransport},
+		upgrade,
+	},
+	dns, identity, noise, tcp, websocket, PeerId, Transport, TransportExt,
+};
+use std::{sync::Arc, time::Duration};
+
+// TODO: Create a wrapper similar to upstream `BandwidthTransport` that tracks sent/received bytes
+#[allow(deprecated)]
+pub use libp2p::bandwidth::BandwidthSinks;
+
+/// Builds the transport that serves as a common ground for all connections.
+///
+/// If `memory_only` is true, then only communication within the same process are allowed. Only
+/// addresses with the format `/memory/...` are allowed.
+///
+/// Returns a `BandwidthSinks` object that allows querying the average bandwidth produced by all
+/// the connections spawned with this transport.
+#[allow(deprecated)]
+pub fn build_transport(
+	keypair: identity::Keypair,
+	memory_only: bool,
+) -> (Boxed<(PeerId, StreamMuxerBox)>, Arc<BandwidthSinks>) {
+	// Build the base layer of the transport.
+	let transport = if !memory_only {
+		// Main transport: DNS(TCP)
+		let tcp_config = tcp::Config::new().nodelay(true);
+		let tcp_trans = tcp::tokio::Transport::new(tcp_config.clone());
+		let dns_init = dns::tokio::Transport::system(tcp_trans);
+
+		Either::Left(if let Ok(dns) = dns_init {
+			// WS + WSS transport
+			//
+			// Main transport can't be used for `/wss` addresses because WSS transport needs
+			// unresolved addresses (BUT WSS transport itself needs an instance of DNS transport to
+			// resolve and dial addresses).
+			let tcp_trans = tcp::tokio::Transport::new(tcp_config);
+			let dns_for_wss = dns::tokio::Transport::system(tcp_trans)
+				.expect("same system_conf & resolver to work");
+			Either::Left(websocket::WsConfig::new(dns_for_wss).or_transport(dns))
+		} else {
+			// In case DNS can't be constructed, fallback to TCP + WS (WSS won't work)
+			let tcp_trans = tcp::tokio::Transport::new(tcp_config.clone());
+			let desktop_trans = websocket::WsConfig::new(tcp_trans)
+				.or_transport(tcp::tokio::Transport::new(tcp_config));
+			Either::Right(desktop_trans)
+		})
+	} else {
+		Either::Right(OptionalTransport::some(libp2p::core::transport::MemoryTransport::default()))
+	};
+
+	let authentication_config = noise::Config::new(&keypair).expect("Can create noise config. qed");
+	let multiplexing_config = libp2p::yamux::Config::default();
+
+	let transport = transport
+		.upgrade(upgrade::Version::V1Lazy)
+		.authenticate(authentication_config)
+		.multiplex(multiplexing_config)
+		.timeout(Duration::from_secs(20))
+		.boxed();
+
+	transport.with_bandwidth_logging()
+}

bizinikiwi/client/network/src/types.rs

@@ -0,0 +1,162 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! `sc-network` type definitions
+
+use std::{
+	borrow::Borrow,
+	fmt,
+	hash::{Hash, Hasher},
+	ops::Deref,
+	sync::Arc,
+};
+
+/// The protocol name transmitted on the wire.
+#[derive(Debug, Clone)]
+pub enum ProtocolName {
+	/// The protocol name as a static string.
+	Static(&'static str),
+	/// The protocol name as a dynamically allocated string.
+	OnHeap(Arc<str>),
+}
+
+impl From<&'static str> for ProtocolName {
+	fn from(name: &'static str) -> Self {
+		Self::Static(name)
+	}
+}
+
+impl From<Arc<str>> for ProtocolName {
+	fn from(name: Arc<str>) -> Self {
+		Self::OnHeap(name)
+	}
+}
+
+impl From<String> for ProtocolName {
+	fn from(name: String) -> Self {
+		Self::OnHeap(Arc::from(name))
+	}
+}
+
+impl Deref for ProtocolName {
+	type Target = str;
+
+	fn deref(&self) -> &str {
+		match self {
+			Self::Static(name) => name,
+			Self::OnHeap(name) => &name,
+		}
+	}
+}
+
+impl Borrow<str> for ProtocolName {
+	fn borrow(&self) -> &str {
+		self
+	}
+}
+
+impl PartialEq for ProtocolName {
+	fn eq(&self, other: &Self) -> bool {
+		(self as &str) == (other as &str)
+	}
+}
+
+impl Eq for ProtocolName {}
+
+impl Hash for ProtocolName {
+	fn hash<H: Hasher>(&self, state: &mut H) {
+		(self as &str).hash(state)
+	}
+}
+
+impl fmt::Display for ProtocolName {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		f.write_str(self)
+	}
+}
+
+impl AsRef<str> for ProtocolName {
+	fn as_ref(&self) -> &str {
+		self as &str
+	}
+}
+
+impl From<ProtocolName> for litep2p::ProtocolName {
+	fn from(protocol: ProtocolName) -> Self {
+		match protocol {
+			ProtocolName::Static(inner) => litep2p::ProtocolName::from(inner),
+			ProtocolName::OnHeap(inner) => litep2p::ProtocolName::from(inner),
+		}
+	}
+}
+
+impl From<litep2p::ProtocolName> for ProtocolName {
+	fn from(protocol: litep2p::ProtocolName) -> Self {
+		match protocol {
+			litep2p::ProtocolName::Static(protocol) => ProtocolName::from(protocol),
+			litep2p::ProtocolName::Allocated(protocol) => ProtocolName::from(protocol),
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::ProtocolName;
+	use std::{
+		borrow::Borrow,
+		collections::hash_map::DefaultHasher,
+		hash::{Hash, Hasher},
+	};
+
+	#[test]
+	fn protocol_name_keys_are_equivalent_to_str_keys() {
+		const PROTOCOL: &'static str = "/some/protocol/1";
+		let static_protocol_name = ProtocolName::from(PROTOCOL);
+		let on_heap_protocol_name = ProtocolName::from(String::from(PROTOCOL));
+
+		assert_eq!(<ProtocolName as Borrow<str>>::borrow(&static_protocol_name), PROTOCOL);
+		assert_eq!(<ProtocolName as Borrow<str>>::borrow(&on_heap_protocol_name), PROTOCOL);
+		assert_eq!(static_protocol_name, on_heap_protocol_name);
+
+		assert_eq!(hash(static_protocol_name), hash(PROTOCOL));
+		assert_eq!(hash(on_heap_protocol_name), hash(PROTOCOL));
+	}
+
+	#[test]
+	fn different_protocol_names_do_not_compare_equal() {
+		const PROTOCOL1: &'static str = "/some/protocol/1";
+		let static_protocol_name1 = ProtocolName::from(PROTOCOL1);
+		let on_heap_protocol_name1 = ProtocolName::from(String::from(PROTOCOL1));
+
+		const PROTOCOL2: &'static str = "/some/protocol/2";
+		let static_protocol_name2 = ProtocolName::from(PROTOCOL2);
+		let on_heap_protocol_name2 = ProtocolName::from(String::from(PROTOCOL2));
+
+		assert_ne!(<ProtocolName as Borrow<str>>::borrow(&static_protocol_name1), PROTOCOL2);
+		assert_ne!(<ProtocolName as Borrow<str>>::borrow(&on_heap_protocol_name1), PROTOCOL2);
+		assert_ne!(static_protocol_name1, static_protocol_name2);
+		assert_ne!(static_protocol_name1, on_heap_protocol_name2);
+		assert_ne!(on_heap_protocol_name1, on_heap_protocol_name2);
+	}
+
+	fn hash<T: Hash>(x: T) -> u64 {
+		let mut hasher = DefaultHasher::new();
+		x.hash(&mut hasher);
+		hasher.finish()
+	}
+}

bizinikiwi/client/network/src/utils.rs

@@ -0,0 +1,88 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! `sc-network` utilities
+
+use futures::{stream::unfold, FutureExt, Stream, StreamExt};
+use futures_timer::Delay;
+use linked_hash_set::LinkedHashSet;
+
+use std::{hash::Hash, num::NonZeroUsize, time::Duration};
+
+/// Creates a stream that returns a new value every `duration`.
+pub fn interval(duration: Duration) -> impl Stream<Item = ()> + Unpin {
+	unfold((), move |_| Delay::new(duration).map(|_| Some(((), ())))).map(drop)
+}
+
+/// Wrapper around `LinkedHashSet` with bounded growth.
+///
+/// In the limit, for each element inserted the oldest existing element will be removed.
+#[derive(Debug, Clone)]
+pub struct LruHashSet<T: Hash + Eq> {
+	set: LinkedHashSet<T>,
+	limit: NonZeroUsize,
+}
+
+impl<T: Hash + Eq> LruHashSet<T> {
+	/// Create a new `LruHashSet` with the given (exclusive) limit.
+	pub fn new(limit: NonZeroUsize) -> Self {
+		Self { set: LinkedHashSet::new(), limit }
+	}
+
+	/// Insert element into the set.
+	///
+	/// Returns `true` if this is a new element to the set, `false` otherwise.
+	/// Maintains the limit of the set by removing the oldest entry if necessary.
+	/// Inserting the same element will update its LRU position.
+	pub fn insert(&mut self, e: T) -> bool {
+		if self.set.insert(e) {
+			if self.set.len() == usize::from(self.limit) {
+				self.set.pop_front(); // remove oldest entry
+			}
+			return true;
+		}
+		false
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn maintains_limit() {
+		let three = NonZeroUsize::new(3).unwrap();
+		let mut set = LruHashSet::<u8>::new(three);
+
+		// First element.
+		assert!(set.insert(1));
+		assert_eq!(vec![&1], set.set.iter().collect::<Vec<_>>());
+
+		// Second element.
+		assert!(set.insert(2));
+		assert_eq!(vec![&1, &2], set.set.iter().collect::<Vec<_>>());
+
+		// Inserting the same element updates its LRU position.
+		assert!(!set.insert(1));
+		assert_eq!(vec![&2, &1], set.set.iter().collect::<Vec<_>>());
+
+		// We reached the limit. The next element forces the oldest one out.
+		assert!(set.insert(3));
+		assert_eq!(vec![&1, &3], set.set.iter().collect::<Vec<_>>());
+	}
+}

bizinikiwi/client/network/statement/Cargo.toml

@@ -0,0 +1,45 @@
+[package]
+description = "Bizinikiwi statement protocol"
+name = "pezsc-network-statement"
+version = "0.16.0"
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+authors.workspace = true
+edition.workspace = true
+homepage.workspace = true
+repository.workspace = true
+documentation = "https://docs.rs/pezsc-network-statement"
+
+[lints]
+workspace = true
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+array-bytes = { workspace = true, default-features = true }
+async-channel = { workspace = true }
+codec = { features = ["derive"], workspace = true, default-features = true }
+futures = { workspace = true }
+log = { workspace = true, default-features = true }
+prometheus-endpoint = { workspace = true, default-features = true }
+pezsc-network = { workspace = true, default-features = true }
+pezsc-network-common = { workspace = true, default-features = true }
+pezsc-network-sync = { workspace = true, default-features = true }
+pezsc-network-types = { workspace = true, default-features = true }
+pezsp-consensus = { workspace = true, default-features = true }
+pezsp-runtime = { workspace = true, default-features = true }
+pezsp-statement-store = { workspace = true, default-features = true }
+tokio = { workspace = true }
+
+[dev-dependencies]
+async-trait = { workspace = true }
+
+[features]
+runtime-benchmarks = [
+	"pezsc-network-common/runtime-benchmarks",
+	"pezsc-network-sync/runtime-benchmarks",
+	"pezsc-network/runtime-benchmarks",
+	"pezsp-consensus/runtime-benchmarks",
+	"pezsp-runtime/runtime-benchmarks",
+	"pezsp-statement-store/runtime-benchmarks",
+]

bizinikiwi/client/network/statement/src/config.rs

@@ -0,0 +1,33 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Configuration of the statement protocol
+
+use std::time;
+
+/// Interval at which we propagate statements;
+pub(crate) const PROPAGATE_TIMEOUT: time::Duration = time::Duration::from_millis(1000);
+
+/// Maximum number of known statement hashes to keep for a peer.
+pub(crate) const MAX_KNOWN_STATEMENTS: usize = 4 * 1024 * 1024; // * 32 bytes for hash = 128 MB per peer
+
+/// Maximum allowed size for a statement notification.
+pub const MAX_STATEMENT_NOTIFICATION_SIZE: u64 = 1024 * 1024;
+
+/// Maximum number of statement validation request we keep at any moment.
+pub(crate) const MAX_PENDING_STATEMENTS: usize = 2 * 1024 * 1024;

bizinikiwi/client/network/sync/Cargo.toml

@@ -0,0 +1,73 @@
+[package]
+description = "Bizinikiwi sync network protocol"
+name = "pezsc-network-sync"
+version = "0.33.0"
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+authors.workspace = true
+edition.workspace = true
+homepage.workspace = true
+repository.workspace = true
+documentation = "https://docs.rs/pezsc-network-sync"
+
+[lints]
+workspace = true
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+array-bytes = { workspace = true, default-features = true }
+async-channel = { workspace = true }
+async-trait = { workspace = true }
+codec = { features = ["derive"], workspace = true, default-features = true }
+fork-tree = { workspace = true, default-features = true }
+futures = { workspace = true }
+log = { workspace = true, default-features = true }
+mockall = { workspace = true }
+prometheus-endpoint = { workspace = true, default-features = true }
+prost = { workspace = true }
+pezsc-client-api = { workspace = true, default-features = true }
+pezsc-consensus = { workspace = true, default-features = true }
+pezsc-network = { workspace = true, default-features = true }
+pezsc-network-common = { workspace = true, default-features = true }
+pezsc-network-types = { workspace = true, default-features = true }
+pezsc-utils = { workspace = true, default-features = true }
+schnellru = { workspace = true }
+smallvec = { workspace = true, default-features = true }
+pezsp-arithmetic = { workspace = true, default-features = true }
+pezsp-blockchain = { workspace = true, default-features = true }
+pezsp-consensus = { workspace = true, default-features = true }
+pezsp-consensus-grandpa = { workspace = true, default-features = true }
+pezsp-core = { workspace = true, default-features = true }
+pezsp-runtime = { workspace = true, default-features = true }
+thiserror = { workspace = true }
+tokio = { features = [
+	"macros",
+	"time",
+], workspace = true, default-features = true }
+tokio-stream = { workspace = true }
+
+[dev-dependencies]
+quickcheck = { workspace = true }
+pezsc-block-builder = { workspace = true, default-features = true }
+pezsp-test-primitives = { workspace = true }
+pezsp-tracing = { workspace = true, default-features = true }
+bizinikiwi-test-runtime-client = { workspace = true }
+
+[build-dependencies]
+prost-build = { workspace = true }
+
+[features]
+runtime-benchmarks = [
+	"pezsc-block-builder/runtime-benchmarks",
+	"pezsc-client-api/runtime-benchmarks",
+	"pezsc-consensus/runtime-benchmarks",
+	"pezsc-network-common/runtime-benchmarks",
+	"pezsc-network/runtime-benchmarks",
+	"pezsp-blockchain/runtime-benchmarks",
+	"pezsp-consensus-grandpa/runtime-benchmarks",
+	"pezsp-consensus/runtime-benchmarks",
+	"pezsp-runtime/runtime-benchmarks",
+	"pezsp-test-primitives/runtime-benchmarks",
+	"bizinikiwi-test-runtime-client/runtime-benchmarks",
+]

bizinikiwi/client/network/sync/build.rs

@@ -0,0 +1,23 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+const PROTOS: &[&str] = &["src/schema/api.v1.proto"];
+
+fn main() {
+	prost_build::compile_protos(PROTOS, &["src/schema"]).unwrap();
+}

bizinikiwi/client/network/sync/src/block_announce_validator.rs

@@ -0,0 +1,410 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! [`BlockAnnounceValidator`] is responsible for async validation of block announcements.
+//! [`Stream`] implemented by [`BlockAnnounceValidator`] never terminates.
+
+use crate::{futures_stream::FuturesStream, LOG_TARGET};
+use futures::{stream::FusedStream, Future, FutureExt, Stream, StreamExt};
+use log::{debug, error, trace, warn};
+use pezsc_network_common::sync::message::BlockAnnounce;
+use pezsc_network_types::PeerId;
+use pezsp_consensus::block_validation::Validation;
+use pezsp_runtime::traits::{Block as BlockT, Header, Zero};
+use std::{
+	collections::{hash_map::Entry, HashMap},
+	default::Default,
+	pin::Pin,
+	task::{Context, Poll},
+};
+
+/// Maximum number of concurrent block announce validations.
+///
+/// If the queue reaches the maximum, we drop any new block
+/// announcements.
+const MAX_CONCURRENT_BLOCK_ANNOUNCE_VALIDATIONS: usize = 256;
+
+/// Maximum number of concurrent block announce validations per peer.
+///
+/// See [`MAX_CONCURRENT_BLOCK_ANNOUNCE_VALIDATIONS`] for more information.
+const MAX_CONCURRENT_BLOCK_ANNOUNCE_VALIDATIONS_PER_PEER: usize = 4;
+
+/// Item that yields [`Stream`] implementation of [`BlockAnnounceValidator`].
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) enum BlockAnnounceValidationResult<H> {
+	/// The announcement failed at validation.
+	///
+	/// The peer reputation should be decreased.
+	Failure {
+		/// The id of the peer that send us the announcement.
+		peer_id: PeerId,
+		/// Should the peer be disconnected?
+		disconnect: bool,
+	},
+	/// The announcement was validated successfully and should be passed to [`crate::ChainSync`].
+	Process {
+		/// The id of the peer that send us the announcement.
+		peer_id: PeerId,
+		/// Was this their new best block?
+		is_new_best: bool,
+		/// The announcement.
+		announce: BlockAnnounce<H>,
+	},
+	/// The block announcement should be skipped.
+	Skip {
+		/// The id of the peer that send us the announcement.
+		peer_id: PeerId,
+	},
+}
+
+impl<H> BlockAnnounceValidationResult<H> {
+	fn peer_id(&self) -> &PeerId {
+		match self {
+			BlockAnnounceValidationResult::Failure { peer_id, .. } |
+			BlockAnnounceValidationResult::Process { peer_id, .. } |
+			BlockAnnounceValidationResult::Skip { peer_id } => peer_id,
+		}
+	}
+}
+
+/// Result of [`BlockAnnounceValidator::allocate_slot_for_block_announce_validation`].
+enum AllocateSlotForBlockAnnounceValidation {
+	/// Success, there is a slot for the block announce validation.
+	Allocated,
+	/// We reached the total maximum number of validation slots.
+	TotalMaximumSlotsReached,
+	/// We reached the maximum number of validation slots for the given peer.
+	MaximumPeerSlotsReached,
+}
+
+pub(crate) struct BlockAnnounceValidator<B: BlockT> {
+	/// A type to check incoming block announcements.
+	validator: Box<dyn pezsp_consensus::block_validation::BlockAnnounceValidator<B> + Send>,
+	/// All block announcements that are currently being validated.
+	validations: FuturesStream<
+		Pin<Box<dyn Future<Output = BlockAnnounceValidationResult<B::Header>> + Send>>,
+	>,
+	/// Number of concurrent block announce validations per peer.
+	validations_per_peer: HashMap<PeerId, usize>,
+}
+
+impl<B: BlockT> BlockAnnounceValidator<B> {
+	pub(crate) fn new(
+		validator: Box<dyn pezsp_consensus::block_validation::BlockAnnounceValidator<B> + Send>,
+	) -> Self {
+		Self {
+			validator,
+			validations: Default::default(),
+			validations_per_peer: Default::default(),
+		}
+	}
+
+	/// Push a block announce validation.
+	pub(crate) fn push_block_announce_validation(
+		&mut self,
+		peer_id: PeerId,
+		hash: B::Hash,
+		announce: BlockAnnounce<B::Header>,
+		is_best: bool,
+	) {
+		let header = &announce.header;
+		let number = *header.number();
+		debug!(
+			target: LOG_TARGET,
+			"Pre-validating received block announcement {:?} with number {:?} from {}",
+			hash,
+			number,
+			peer_id,
+		);
+
+		if number.is_zero() {
+			warn!(
+				target: LOG_TARGET,
+				"💔 Ignored genesis block (#0) announcement from {}: {}",
+				peer_id,
+				hash,
+			);
+			return;
+		}
+
+		// Try to allocate a slot for this block announce validation.
+		match self.allocate_slot_for_block_announce_validation(&peer_id) {
+			AllocateSlotForBlockAnnounceValidation::Allocated => {},
+			AllocateSlotForBlockAnnounceValidation::TotalMaximumSlotsReached => {
+				warn!(
+					target: LOG_TARGET,
+					"💔 Ignored block (#{} -- {}) announcement from {} because all validation slots are occupied.",
+					number,
+					hash,
+					peer_id,
+				);
+				return;
+			},
+			AllocateSlotForBlockAnnounceValidation::MaximumPeerSlotsReached => {
+				debug!(
+					target: LOG_TARGET,
+					"💔 Ignored block (#{} -- {}) announcement from {} because all validation slots for this peer are occupied.",
+					number,
+					hash,
+					peer_id,
+				);
+				return;
+			},
+		}
+
+		// Let external validator check the block announcement.
+		let assoc_data = announce.data.as_ref().map_or(&[][..], |v| v.as_slice());
+		let future = self.validator.validate(header, assoc_data);
+
+		self.validations.push(
+			async move {
+				match future.await {
+					Ok(Validation::Success { is_new_best }) => {
+						let is_new_best = is_new_best || is_best;
+
+						trace!(
+							target: LOG_TARGET,
+							"Block announcement validated successfully: from {}: {:?}. Local best: {}.",
+							peer_id,
+							announce.summary(),
+							is_new_best,
+						);
+
+						BlockAnnounceValidationResult::Process { is_new_best, announce, peer_id }
+					},
+					Ok(Validation::Failure { disconnect }) => {
+						debug!(
+							target: LOG_TARGET,
+							"Block announcement validation failed: from {}, block {:?}. Disconnect: {}.",
+							peer_id,
+							hash,
+							disconnect,
+						);
+
+						BlockAnnounceValidationResult::Failure { peer_id, disconnect }
+					},
+					Err(e) => {
+						debug!(
+							target: LOG_TARGET,
+							"💔 Ignoring block announcement validation from {} of block {:?} due to internal error: {}.",
+							peer_id,
+							hash,
+							e,
+						);
+
+						BlockAnnounceValidationResult::Skip { peer_id }
+					},
+				}
+			}
+			.boxed(),
+		);
+	}
+
+	/// Checks if there is a slot for a block announce validation.
+	///
+	/// The total number and the number per peer of concurrent block announce validations
+	/// is capped.
+	///
+	/// Returns [`AllocateSlotForBlockAnnounceValidation`] to inform about the result.
+	///
+	/// # Note
+	///
+	/// It is *required* to call [`Self::deallocate_slot_for_block_announce_validation`] when the
+	/// validation is finished to clear the slot.
+	fn allocate_slot_for_block_announce_validation(
+		&mut self,
+		peer_id: &PeerId,
+	) -> AllocateSlotForBlockAnnounceValidation {
+		if self.validations.len() >= MAX_CONCURRENT_BLOCK_ANNOUNCE_VALIDATIONS {
+			return AllocateSlotForBlockAnnounceValidation::TotalMaximumSlotsReached;
+		}
+
+		match self.validations_per_peer.entry(*peer_id) {
+			Entry::Vacant(entry) => {
+				entry.insert(1);
+				AllocateSlotForBlockAnnounceValidation::Allocated
+			},
+			Entry::Occupied(mut entry) => {
+				if *entry.get() < MAX_CONCURRENT_BLOCK_ANNOUNCE_VALIDATIONS_PER_PEER {
+					*entry.get_mut() += 1;
+					AllocateSlotForBlockAnnounceValidation::Allocated
+				} else {
+					AllocateSlotForBlockAnnounceValidation::MaximumPeerSlotsReached
+				}
+			},
+		}
+	}
+
+	/// Should be called when a block announce validation is finished, to update the slots
+	/// of the peer that send the block announce.
+	fn deallocate_slot_for_block_announce_validation(&mut self, peer_id: &PeerId) {
+		match self.validations_per_peer.entry(*peer_id) {
+			Entry::Vacant(_) => {
+				error!(
+					target: LOG_TARGET,
+					"💔 Block announcement validation from peer {} finished for a slot that was not allocated!",
+					peer_id,
+				);
+			},
+			Entry::Occupied(mut entry) => match entry.get().checked_sub(1) {
+				Some(value) =>
+					if value == 0 {
+						entry.remove();
+					} else {
+						*entry.get_mut() = value;
+					},
+				None => {
+					entry.remove();
+
+					error!(
+						target: LOG_TARGET,
+						"Invalid (zero) block announce validation slot counter for peer {peer_id}.",
+					);
+					debug_assert!(
+						false,
+						"Invalid (zero) block announce validation slot counter for peer {peer_id}.",
+					);
+				},
+			},
+		}
+	}
+}
+
+impl<B: BlockT> Stream for BlockAnnounceValidator<B> {
+	type Item = BlockAnnounceValidationResult<B::Header>;
+
+	/// Poll for finished block announce validations. The stream never terminates.
+	fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+		let validation = futures::ready!(self.validations.poll_next_unpin(cx))
+			.expect("`FuturesStream` never terminates; qed");
+		self.deallocate_slot_for_block_announce_validation(validation.peer_id());
+
+		Poll::Ready(Some(validation))
+	}
+}
+
+// As [`BlockAnnounceValidator`] never terminates, we can easily implement [`FusedStream`] for it.
+impl<B: BlockT> FusedStream for BlockAnnounceValidator<B> {
+	fn is_terminated(&self) -> bool {
+		false
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::block_announce_validator::AllocateSlotForBlockAnnounceValidation;
+	use pezsc_network_types::PeerId;
+	use pezsp_consensus::block_validation::DefaultBlockAnnounceValidator;
+	use bizinikiwi_test_runtime_client::runtime::Block;
+
+	#[test]
+	fn allocate_one_validation_slot() {
+		let mut validator =
+			BlockAnnounceValidator::<Block>::new(Box::new(DefaultBlockAnnounceValidator {}));
+		let peer_id = PeerId::random();
+
+		assert!(matches!(
+			validator.allocate_slot_for_block_announce_validation(&peer_id),
+			AllocateSlotForBlockAnnounceValidation::Allocated,
+		));
+	}
+
+	#[test]
+	fn allocate_validation_slots_for_two_peers() {
+		let mut validator =
+			BlockAnnounceValidator::<Block>::new(Box::new(DefaultBlockAnnounceValidator {}));
+		let peer_id_1 = PeerId::random();
+		let peer_id_2 = PeerId::random();
+
+		assert!(matches!(
+			validator.allocate_slot_for_block_announce_validation(&peer_id_1),
+			AllocateSlotForBlockAnnounceValidation::Allocated,
+		));
+		assert!(matches!(
+			validator.allocate_slot_for_block_announce_validation(&peer_id_2),
+			AllocateSlotForBlockAnnounceValidation::Allocated,
+		));
+	}
+
+	#[test]
+	fn maximum_validation_slots_per_peer() {
+		let mut validator =
+			BlockAnnounceValidator::<Block>::new(Box::new(DefaultBlockAnnounceValidator {}));
+		let peer_id = PeerId::random();
+
+		for _ in 0..MAX_CONCURRENT_BLOCK_ANNOUNCE_VALIDATIONS_PER_PEER {
+			assert!(matches!(
+				validator.allocate_slot_for_block_announce_validation(&peer_id),
+				AllocateSlotForBlockAnnounceValidation::Allocated,
+			));
+		}
+
+		assert!(matches!(
+			validator.allocate_slot_for_block_announce_validation(&peer_id),
+			AllocateSlotForBlockAnnounceValidation::MaximumPeerSlotsReached,
+		));
+	}
+
+	#[test]
+	fn validation_slots_per_peer_deallocated() {
+		let mut validator =
+			BlockAnnounceValidator::<Block>::new(Box::new(DefaultBlockAnnounceValidator {}));
+		let peer_id = PeerId::random();
+
+		for _ in 0..MAX_CONCURRENT_BLOCK_ANNOUNCE_VALIDATIONS_PER_PEER {
+			assert!(matches!(
+				validator.allocate_slot_for_block_announce_validation(&peer_id),
+				AllocateSlotForBlockAnnounceValidation::Allocated,
+			));
+		}
+
+		assert!(matches!(
+			validator.allocate_slot_for_block_announce_validation(&peer_id),
+			AllocateSlotForBlockAnnounceValidation::MaximumPeerSlotsReached,
+		));
+
+		validator.deallocate_slot_for_block_announce_validation(&peer_id);
+
+		assert!(matches!(
+			validator.allocate_slot_for_block_announce_validation(&peer_id),
+			AllocateSlotForBlockAnnounceValidation::Allocated,
+		));
+	}
+
+	#[test]
+	fn maximum_validation_slots_for_all_peers() {
+		let mut validator =
+			BlockAnnounceValidator::<Block>::new(Box::new(DefaultBlockAnnounceValidator {}));
+
+		for _ in 0..MAX_CONCURRENT_BLOCK_ANNOUNCE_VALIDATIONS {
+			validator.validations.push(
+				futures::future::ready(BlockAnnounceValidationResult::Skip {
+					peer_id: PeerId::random(),
+				})
+				.boxed(),
+			);
+		}
+
+		let peer_id = PeerId::random();
+		assert!(matches!(
+			validator.allocate_slot_for_block_announce_validation(&peer_id),
+			AllocateSlotForBlockAnnounceValidation::TotalMaximumSlotsReached,
+		));
+	}
+}

bizinikiwi/client/network/sync/src/block_relay_protocol.rs

@@ -0,0 +1,76 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Bizinikiwi.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// Bizinikiwi is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Bizinikiwi is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Bizinikiwi. If not, see <https://www.gnu.org/licenses/>.
+
+//! Block relay protocol related definitions.
+
+use futures::channel::oneshot;
+use pezsc_network::{request_responses::RequestFailure, NetworkBackend, ProtocolName};
+use pezsc_network_common::sync::message::{BlockData, BlockRequest};
+use pezsc_network_types::PeerId;
+use pezsp_runtime::traits::Block as BlockT;
+use std::{fmt, sync::Arc};
+
+/// The serving side of the block relay protocol. It runs a single instance
+/// of the server task that processes the incoming protocol messages.
+#[async_trait::async_trait]
+pub trait BlockServer<Block: BlockT>: Send {
+	/// Starts the protocol processing.
+	async fn run(&mut self);
+}
+
+/// The client side stub to download blocks from peers. This is a handle
+/// that can be used to initiate concurrent downloads.
+#[async_trait::async_trait]
+pub trait BlockDownloader<Block: BlockT>: fmt::Debug + Send + Sync {
+	/// Protocol name used by block downloader.
+	fn protocol_name(&self) -> &ProtocolName;
+
+	/// Performs the protocol specific sequence to fetch the blocks from the peer.
+	/// Output: if the download succeeds, the response is a `Vec<u8>` which is
+	/// in a format specific to the protocol implementation. The block data
+	/// can be extracted from this response using [`BlockDownloader::block_response_into_blocks`].
+	async fn download_blocks(
+		&self,
+		who: PeerId,
+		request: BlockRequest<Block>,
+	) -> Result<Result<(Vec<u8>, ProtocolName), RequestFailure>, oneshot::Canceled>;
+
+	/// Parses the protocol specific response to retrieve the block data.
+	fn block_response_into_blocks(
+		&self,
+		request: &BlockRequest<Block>,
+		response: Vec<u8>,
+	) -> Result<Vec<BlockData<Block>>, BlockResponseError>;
+}
+
+/// Errors returned by [`BlockDownloader::block_response_into_blocks`].
+#[derive(Debug)]
+pub enum BlockResponseError {
+	/// Failed to decode the response bytes.
+	DecodeFailed(String),
+
+	/// Failed to extract the blocks from the decoded bytes.
+	ExtractionFailed(String),
+}
+
+/// Block relay specific params for network creation, specified in
+/// ['pezsc_service::BuildNetworkParams'].
+pub struct BlockRelayParams<Block: BlockT, N: NetworkBackend<Block, <Block as BlockT>::Hash>> {
+	pub server: Box<dyn BlockServer<Block>>,
+	pub downloader: Arc<dyn BlockDownloader<Block>>,
+	pub request_response_config: N::RequestResponseProtocolConfig,
+}

bizinikiwi/client/network/sync/src/block_request_handler.rs

@@ -0,0 +1,627 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Bizinikiwi.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// Bizinikiwi is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Bizinikiwi is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Bizinikiwi. If not, see <https://www.gnu.org/licenses/>.
+
+//! Helper for handling (i.e. answering) block requests from a remote peer via the
+//! `crate::request_responses::RequestResponsesBehaviour`.
+
+use crate::{
+	block_relay_protocol::{BlockDownloader, BlockRelayParams, BlockResponseError, BlockServer},
+	schema::v1::{
+		block_request::FromBlock as FromBlockSchema, BlockRequest as BlockRequestSchema,
+		BlockResponse as BlockResponseSchema, BlockResponse, Direction,
+	},
+	service::network::NetworkServiceHandle,
+	LOG_TARGET,
+};
+
+use codec::{Decode, DecodeAll, Encode};
+use futures::{channel::oneshot, stream::StreamExt};
+use log::debug;
+use prost::Message;
+use schnellru::{ByLength, LruMap};
+
+use pezsc_client_api::BlockBackend;
+use pezsc_network::{
+	config::ProtocolId,
+	request_responses::{IfDisconnected, IncomingRequest, OutgoingResponse, RequestFailure},
+	service::traits::RequestResponseConfig,
+	types::ProtocolName,
+	NetworkBackend, MAX_RESPONSE_SIZE,
+};
+use pezsc_network_common::sync::message::{BlockAttributes, BlockData, BlockRequest, FromBlock};
+use pezsc_network_types::PeerId;
+use pezsp_blockchain::HeaderBackend;
+use pezsp_runtime::{
+	generic::BlockId,
+	traits::{Block as BlockT, Header, One, Zero},
+};
+
+use std::{
+	cmp::min,
+	hash::{Hash, Hasher},
+	sync::Arc,
+	time::Duration,
+};
+
+/// Maximum blocks per response.
+pub(crate) const MAX_BLOCKS_IN_RESPONSE: usize = 128;
+
+const MAX_BODY_BYTES: usize = 8 * 1024 * 1024;
+const MAX_NUMBER_OF_SAME_REQUESTS_PER_PEER: usize = 2;
+
+mod rep {
+	use pezsc_network::ReputationChange as Rep;
+
+	/// Reputation change when a peer sent us the same request multiple times.
+	pub const SAME_REQUEST: Rep = Rep::new_fatal("Same block request multiple times");
+
+	/// Reputation change when a peer sent us the same "small" request multiple times.
+	pub const SAME_SMALL_REQUEST: Rep =
+		Rep::new(-(1 << 10), "same small block request multiple times");
+}
+
+/// Generates a `RequestResponseProtocolConfig` for the block request protocol,
+/// refusing incoming requests.
+pub fn generate_protocol_config<
+	Hash: AsRef<[u8]>,
+	B: BlockT,
+	N: NetworkBackend<B, <B as BlockT>::Hash>,
+>(
+	protocol_id: &ProtocolId,
+	genesis_hash: Hash,
+	fork_id: Option<&str>,
+	inbound_queue: async_channel::Sender<IncomingRequest>,
+) -> N::RequestResponseProtocolConfig {
+	N::request_response_config(
+		generate_protocol_name(genesis_hash, fork_id).into(),
+		std::iter::once(generate_legacy_protocol_name(protocol_id).into()).collect(),
+		1024 * 1024,
+		MAX_RESPONSE_SIZE,
+		Duration::from_secs(20),
+		Some(inbound_queue),
+	)
+}
+
+/// Generate the block protocol name from the genesis hash and fork id.
+fn generate_protocol_name<Hash: AsRef<[u8]>>(genesis_hash: Hash, fork_id: Option<&str>) -> String {
+	let genesis_hash = genesis_hash.as_ref();
+	if let Some(fork_id) = fork_id {
+		format!("/{}/{}/sync/2", array_bytes::bytes2hex("", genesis_hash), fork_id)
+	} else {
+		format!("/{}/sync/2", array_bytes::bytes2hex("", genesis_hash))
+	}
+}
+
+/// Generate the legacy block protocol name from chain specific protocol identifier.
+fn generate_legacy_protocol_name(protocol_id: &ProtocolId) -> String {
+	format!("/{}/sync/2", protocol_id.as_ref())
+}
+
+/// The key of [`BlockRequestHandler::seen_requests`].
+#[derive(Eq, PartialEq, Clone)]
+struct SeenRequestsKey<B: BlockT> {
+	peer: PeerId,
+	from: BlockId<B>,
+	max_blocks: usize,
+	direction: Direction,
+	attributes: BlockAttributes,
+	support_multiple_justifications: bool,
+}
+
+#[allow(clippy::derived_hash_with_manual_eq)]
+impl<B: BlockT> Hash for SeenRequestsKey<B> {
+	fn hash<H: Hasher>(&self, state: &mut H) {
+		self.peer.hash(state);
+		self.max_blocks.hash(state);
+		self.direction.hash(state);
+		self.attributes.hash(state);
+		self.support_multiple_justifications.hash(state);
+		match self.from {
+			BlockId::Hash(h) => h.hash(state),
+			BlockId::Number(n) => n.hash(state),
+		}
+	}
+}
+
+/// The value of [`BlockRequestHandler::seen_requests`].
+enum SeenRequestsValue {
+	/// First time we have seen the request.
+	First,
+	/// We have fulfilled the request `n` times.
+	Fulfilled(usize),
+}
+
+/// The full block server implementation of [`BlockServer`]. It handles
+/// the incoming block requests from a remote peer.
+pub struct BlockRequestHandler<B: BlockT, Client> {
+	client: Arc<Client>,
+	request_receiver: async_channel::Receiver<IncomingRequest>,
+	/// Maps from request to number of times we have seen this request.
+	///
+	/// This is used to check if a peer is spamming us with the same request.
+	seen_requests: LruMap<SeenRequestsKey<B>, SeenRequestsValue>,
+}
+
+impl<B, Client> BlockRequestHandler<B, Client>
+where
+	B: BlockT,
+	Client: HeaderBackend<B> + BlockBackend<B> + Send + Sync + 'static,
+{
+	/// Create a new [`BlockRequestHandler`].
+	pub fn new<N: NetworkBackend<B, <B as BlockT>::Hash>>(
+		network: NetworkServiceHandle,
+		protocol_id: &ProtocolId,
+		fork_id: Option<&str>,
+		client: Arc<Client>,
+		num_peer_hint: usize,
+	) -> BlockRelayParams<B, N> {
+		// Reserve enough request slots for one request per peer when we are at the maximum
+		// number of peers.
+		let capacity = std::cmp::max(num_peer_hint, 1);
+		let (tx, request_receiver) = async_channel::bounded(capacity);
+
+		let protocol_config = generate_protocol_config::<_, B, N>(
+			protocol_id,
+			client
+				.block_hash(0u32.into())
+				.ok()
+				.flatten()
+				.expect("Genesis block exists; qed"),
+			fork_id,
+			tx,
+		);
+
+		let capacity = ByLength::new(num_peer_hint.max(1) as u32 * 2);
+		let seen_requests = LruMap::new(capacity);
+
+		BlockRelayParams {
+			server: Box::new(Self { client, request_receiver, seen_requests }),
+			downloader: Arc::new(FullBlockDownloader::new(
+				protocol_config.protocol_name().clone(),
+				network,
+			)),
+			request_response_config: protocol_config,
+		}
+	}
+
+	/// Run [`BlockRequestHandler`].
+	async fn process_requests(&mut self) {
+		while let Some(request) = self.request_receiver.next().await {
+			let IncomingRequest { peer, payload, pending_response } = request;
+
+			match self.handle_request(payload, pending_response, &peer) {
+				Ok(()) => debug!(target: LOG_TARGET, "Handled block request from {}.", peer),
+				Err(e) => debug!(
+					target: LOG_TARGET,
+					"Failed to handle block request from {}: {}", peer, e,
+				),
+			}
+		}
+	}
+
+	fn handle_request(
+		&mut self,
+		payload: Vec<u8>,
+		pending_response: oneshot::Sender<OutgoingResponse>,
+		peer: &PeerId,
+	) -> Result<(), HandleRequestError> {
+		let request = crate::schema::v1::BlockRequest::decode(&payload[..])?;
+
+		let from_block_id = match request.from_block.ok_or(HandleRequestError::MissingFromField)? {
+			FromBlockSchema::Hash(ref h) => {
+				let h = Decode::decode(&mut h.as_ref())?;
+				BlockId::<B>::Hash(h)
+			},
+			FromBlockSchema::Number(ref n) => {
+				let n = Decode::decode(&mut n.as_ref())?;
+				BlockId::<B>::Number(n)
+			},
+		};
+
+		let max_blocks = if request.max_blocks == 0 {
+			MAX_BLOCKS_IN_RESPONSE
+		} else {
+			min(request.max_blocks as usize, MAX_BLOCKS_IN_RESPONSE)
+		};
+
+		let direction =
+			i32::try_into(request.direction).map_err(|_| HandleRequestError::ParseDirection)?;
+
+		let attributes = BlockAttributes::from_be_u32(request.fields)?;
+
+		let support_multiple_justifications = request.support_multiple_justifications;
+
+		let key = SeenRequestsKey {
+			peer: *peer,
+			max_blocks,
+			direction,
+			from: from_block_id,
+			attributes,
+			support_multiple_justifications,
+		};
+
+		let mut reputation_change = None;
+
+		let small_request = attributes
+			.difference(BlockAttributes::HEADER | BlockAttributes::JUSTIFICATION)
+			.is_empty();
+
+		match self.seen_requests.get(&key) {
+			Some(SeenRequestsValue::First) => {},
+			Some(SeenRequestsValue::Fulfilled(ref mut requests)) => {
+				*requests = requests.saturating_add(1);
+
+				if *requests > MAX_NUMBER_OF_SAME_REQUESTS_PER_PEER {
+					reputation_change = Some(if small_request {
+						rep::SAME_SMALL_REQUEST
+					} else {
+						rep::SAME_REQUEST
+					});
+				}
+			},
+			None => {
+				self.seen_requests.insert(key.clone(), SeenRequestsValue::First);
+			},
+		}
+
+		debug!(
+			target: LOG_TARGET,
+			"Handling block request from {peer}: Starting at `{from_block_id:?}` with \
+			maximum blocks of `{max_blocks}`, reputation_change: `{reputation_change:?}`, \
+			small_request `{small_request:?}`, direction `{direction:?}` and \
+			attributes `{attributes:?}`.",
+		);
+
+		let maybe_block_response = if reputation_change.is_none() || small_request {
+			let block_response = self.get_block_response(
+				attributes,
+				from_block_id,
+				direction,
+				max_blocks,
+				support_multiple_justifications,
+			)?;
+
+			// If any of the blocks contains any data, we can consider it as successful request.
+			if block_response
+				.blocks
+				.iter()
+				.any(|b| !b.header.is_empty() || !b.body.is_empty() || b.is_empty_justification)
+			{
+				if let Some(value) = self.seen_requests.get(&key) {
+					// If this is the first time we have processed this request, we need to change
+					// it to `Fulfilled`.
+					if let SeenRequestsValue::First = value {
+						*value = SeenRequestsValue::Fulfilled(1);
+					}
+				}
+			}
+
+			Some(block_response)
+		} else {
+			None
+		};
+
+		debug!(
+			target: LOG_TARGET,
+			"Sending result of block request from {peer} starting at `{from_block_id:?}`: \
+			blocks: {:?}, data: {:?}",
+			maybe_block_response.as_ref().map(|res| res.blocks.len()),
+			maybe_block_response.as_ref().map(|res| res.encoded_len()),
+		);
+
+		let result = if let Some(block_response) = maybe_block_response {
+			let mut data = Vec::with_capacity(block_response.encoded_len());
+			block_response.encode(&mut data)?;
+			Ok(data)
+		} else {
+			Err(())
+		};
+
+		pending_response
+			.send(OutgoingResponse {
+				result,
+				reputation_changes: reputation_change.into_iter().collect(),
+				sent_feedback: None,
+			})
+			.map_err(|_| HandleRequestError::SendResponse)
+	}
+
+	fn get_block_response(
+		&self,
+		attributes: BlockAttributes,
+		mut block_id: BlockId<B>,
+		direction: Direction,
+		max_blocks: usize,
+		support_multiple_justifications: bool,
+	) -> Result<BlockResponse, HandleRequestError> {
+		let get_header = attributes.contains(BlockAttributes::HEADER);
+		let get_body = attributes.contains(BlockAttributes::BODY);
+		let get_indexed_body = attributes.contains(BlockAttributes::INDEXED_BODY);
+		let get_justification = attributes.contains(BlockAttributes::JUSTIFICATION);
+
+		let mut blocks = Vec::new();
+
+		let mut total_size: usize = 0;
+
+		let client_header_from_block_id =
+			|block_id: BlockId<B>| -> Result<Option<B::Header>, HandleRequestError> {
+				if let Some(hash) = self.client.block_hash_from_id(&block_id)? {
+					return self.client.header(hash).map_err(Into::into);
+				}
+				Ok(None)
+			};
+
+		while let Some(header) = client_header_from_block_id(block_id).unwrap_or_default() {
+			let number = *header.number();
+			let hash = header.hash();
+			let parent_hash = *header.parent_hash();
+			let justifications =
+				if get_justification { self.client.justifications(hash)? } else { None };
+
+			let (justifications, justification, is_empty_justification) =
+				if support_multiple_justifications {
+					let justifications = match justifications {
+						Some(v) => v.encode(),
+						None => Vec::new(),
+					};
+					(justifications, Vec::new(), false)
+				} else {
+					// For now we keep compatibility by selecting precisely the GRANDPA one, and not
+					// just the first one. When sending we could have just taken the first one,
+					// since we don't expect there to be any other kind currently, but when
+					// receiving we need to add the engine ID tag.
+					// The ID tag is hardcoded here to avoid depending on the GRANDPA crate, and
+					// will be removed once we remove the backwards compatibility.
+					// See: https://github.com/pezkuwichain/kurdistan-sdk/issues/32
+					let justification =
+						justifications.and_then(|just| just.into_justification(*b"FRNK"));
+
+					let is_empty_justification =
+						justification.as_ref().map(|j| j.is_empty()).unwrap_or(false);
+
+					let justification = justification.unwrap_or_default();
+
+					(Vec::new(), justification, is_empty_justification)
+				};
+
+			let body = if get_body {
+				match self.client.block_body(hash)? {
+					Some(mut extrinsics) =>
+						extrinsics.iter_mut().map(|extrinsic| extrinsic.encode()).collect(),
+					None => {
+						log::trace!(target: LOG_TARGET, "Missing data for block request.");
+						break;
+					},
+				}
+			} else {
+				Vec::new()
+			};
+
+			let indexed_body = if get_indexed_body {
+				match self.client.block_indexed_body(hash)? {
+					Some(transactions) => transactions,
+					None => {
+						log::trace!(
+							target: LOG_TARGET,
+							"Missing indexed block data for block request."
+						);
+						// If the indexed body is missing we still continue returning headers.
+						// Ideally `None` should distinguish a missing body from the empty body,
+						// but the current protobuf based protocol does not allow it.
+						Vec::new()
+					},
+				}
+			} else {
+				Vec::new()
+			};
+
+			let block_data = crate::schema::v1::BlockData {
+				hash: hash.encode(),
+				header: if get_header { header.encode() } else { Vec::new() },
+				body,
+				receipt: Vec::new(),
+				message_queue: Vec::new(),
+				justification,
+				is_empty_justification,
+				justifications,
+				indexed_body,
+			};
+
+			let new_total_size = total_size +
+				block_data.body.iter().map(|ex| ex.len()).sum::<usize>() +
+				block_data.indexed_body.iter().map(|ex| ex.len()).sum::<usize>();
+
+			// Send at least one block, but make sure to not exceed the limit.
+			if !blocks.is_empty() && new_total_size > MAX_BODY_BYTES {
+				break;
+			}
+
+			total_size = new_total_size;
+
+			blocks.push(block_data);
+
+			if blocks.len() >= max_blocks as usize {
+				break;
+			}
+
+			match direction {
+				Direction::Ascending => block_id = BlockId::Number(number + One::one()),
+				Direction::Descending => {
+					if number.is_zero() {
+						break;
+					}
+					block_id = BlockId::Hash(parent_hash)
+				},
+			}
+		}
+
+		Ok(BlockResponse { blocks })
+	}
+}
+
+#[async_trait::async_trait]
+impl<B, Client> BlockServer<B> for BlockRequestHandler<B, Client>
+where
+	B: BlockT,
+	Client: HeaderBackend<B> + BlockBackend<B> + Send + Sync + 'static,
+{
+	async fn run(&mut self) {
+		self.process_requests().await;
+	}
+}
+
+#[derive(Debug, thiserror::Error)]
+enum HandleRequestError {
+	#[error("Failed to decode request: {0}.")]
+	DecodeProto(#[from] prost::DecodeError),
+	#[error("Failed to encode response: {0}.")]
+	EncodeProto(#[from] prost::EncodeError),
+	#[error("Failed to decode block hash: {0}.")]
+	DecodeScale(#[from] codec::Error),
+	#[error("Missing `BlockRequest::from_block` field.")]
+	MissingFromField,
+	#[error("Failed to parse BlockRequest::direction.")]
+	ParseDirection,
+	#[error(transparent)]
+	Client(#[from] pezsp_blockchain::Error),
+	#[error("Failed to send response.")]
+	SendResponse,
+}
+
+/// The full block downloader implementation of [`BlockDownloader].
+#[derive(Debug)]
+pub struct FullBlockDownloader {
+	protocol_name: ProtocolName,
+	network: NetworkServiceHandle,
+}
+
+impl FullBlockDownloader {
+	fn new(protocol_name: ProtocolName, network: NetworkServiceHandle) -> Self {
+		Self { protocol_name, network }
+	}
+
+	/// Extracts the blocks from the response schema.
+	fn blocks_from_schema<B: BlockT>(
+		&self,
+		request: &BlockRequest<B>,
+		response: BlockResponseSchema,
+	) -> Result<Vec<BlockData<B>>, String> {
+		response
+			.blocks
+			.into_iter()
+			.map(|block_data| {
+				Ok(BlockData::<B> {
+					hash: Decode::decode(&mut block_data.hash.as_ref())?,
+					header: if !block_data.header.is_empty() {
+						Some(Decode::decode(&mut block_data.header.as_ref())?)
+					} else {
+						None
+					},
+					body: if request.fields.contains(BlockAttributes::BODY) {
+						Some(
+							block_data
+								.body
+								.iter()
+								.map(|body| Decode::decode(&mut body.as_ref()))
+								.collect::<Result<Vec<_>, _>>()?,
+						)
+					} else {
+						None
+					},
+					indexed_body: if request.fields.contains(BlockAttributes::INDEXED_BODY) {
+						Some(block_data.indexed_body)
+					} else {
+						None
+					},
+					receipt: if !block_data.receipt.is_empty() {
+						Some(block_data.receipt)
+					} else {
+						None
+					},
+					message_queue: if !block_data.message_queue.is_empty() {
+						Some(block_data.message_queue)
+					} else {
+						None
+					},
+					justification: if !block_data.justification.is_empty() {
+						Some(block_data.justification)
+					} else if block_data.is_empty_justification {
+						Some(Vec::new())
+					} else {
+						None
+					},
+					justifications: if !block_data.justifications.is_empty() {
+						Some(DecodeAll::decode_all(&mut block_data.justifications.as_ref())?)
+					} else {
+						None
+					},
+				})
+			})
+			.collect::<Result<_, _>>()
+			.map_err(|error: codec::Error| error.to_string())
+	}
+}
+
+#[async_trait::async_trait]
+impl<B: BlockT> BlockDownloader<B> for FullBlockDownloader {
+	fn protocol_name(&self) -> &ProtocolName {
+		&self.protocol_name
+	}
+
+	async fn download_blocks(
+		&self,
+		who: PeerId,
+		request: BlockRequest<B>,
+	) -> Result<Result<(Vec<u8>, ProtocolName), RequestFailure>, oneshot::Canceled> {
+		// Build the request protobuf.
+		let bytes = BlockRequestSchema {
+			fields: request.fields.to_be_u32(),
+			from_block: match request.from {
+				FromBlock::Hash(h) => Some(FromBlockSchema::Hash(h.encode())),
+				FromBlock::Number(n) => Some(FromBlockSchema::Number(n.encode())),
+			},
+			direction: request.direction as i32,
+			max_blocks: request.max.unwrap_or(0),
+			support_multiple_justifications: true,
+		}
+		.encode_to_vec();
+
+		let (tx, rx) = oneshot::channel();
+		self.network.start_request(
+			who,
+			self.protocol_name.clone(),
+			bytes,
+			tx,
+			IfDisconnected::ImmediateError,
+		);
+		rx.await
+	}
+
+	fn block_response_into_blocks(
+		&self,
+		request: &BlockRequest<B>,
+		response: Vec<u8>,
+	) -> Result<Vec<BlockData<B>>, BlockResponseError> {
+		// Decode the response protobuf
+		let response_schema = BlockResponseSchema::decode(response.as_slice())
+			.map_err(|error| BlockResponseError::DecodeFailed(error.to_string()))?;
+
+		// Extract the block data from the protobuf
+		self.blocks_from_schema::<B>(request, response_schema)
+			.map_err(|error| BlockResponseError::ExtractionFailed(error.to_string()))
+	}
+}

bizinikiwi/client/network/sync/src/blocks.rs

@@ -0,0 +1,649 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::LOG_TARGET;
+use log::trace;
+use pezsc_network_common::sync::message;
+use pezsc_network_types::PeerId;
+use pezsp_runtime::traits::{Block as BlockT, NumberFor, One};
+use std::{
+	cmp,
+	collections::{BTreeMap, HashMap},
+	ops::Range,
+};
+
+/// Block data with origin.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct BlockData<B: BlockT> {
+	/// The Block Message from the wire
+	pub block: message::BlockData<B>,
+	/// The peer, we received this from
+	pub origin: Option<PeerId>,
+}
+
+#[derive(Debug)]
+enum BlockRangeState<B: BlockT> {
+	Downloading { len: NumberFor<B>, downloading: u32 },
+	Complete(Vec<BlockData<B>>),
+	Queued { len: NumberFor<B> },
+}
+
+impl<B: BlockT> BlockRangeState<B> {
+	pub fn len(&self) -> NumberFor<B> {
+		match *self {
+			Self::Downloading { len, .. } => len,
+			Self::Complete(ref blocks) => (blocks.len() as u32).into(),
+			Self::Queued { len } => len,
+		}
+	}
+}
+
+/// A collection of blocks being downloaded.
+#[derive(Default)]
+pub struct BlockCollection<B: BlockT> {
+	/// Downloaded blocks.
+	blocks: BTreeMap<NumberFor<B>, BlockRangeState<B>>,
+	peer_requests: HashMap<PeerId, NumberFor<B>>,
+	/// Block ranges downloaded and queued for import.
+	/// Maps start_hash => (start_num, end_num).
+	queued_blocks: HashMap<B::Hash, (NumberFor<B>, NumberFor<B>)>,
+}
+
+impl<B: BlockT> BlockCollection<B> {
+	/// Create a new instance.
+	pub fn new() -> Self {
+		Self {
+			blocks: BTreeMap::new(),
+			peer_requests: HashMap::new(),
+			queued_blocks: HashMap::new(),
+		}
+	}
+
+	/// Clear everything.
+	pub fn clear(&mut self) {
+		self.blocks.clear();
+		self.peer_requests.clear();
+	}
+
+	/// Insert a set of blocks into collection.
+	pub fn insert(&mut self, start: NumberFor<B>, blocks: Vec<message::BlockData<B>>, who: PeerId) {
+		if blocks.is_empty() {
+			return;
+		}
+
+		match self.blocks.get(&start) {
+			Some(&BlockRangeState::Downloading { .. }) => {
+				trace!(target: LOG_TARGET, "Inserting block data still marked as being downloaded: {}", start);
+			},
+			Some(BlockRangeState::Complete(existing)) if existing.len() >= blocks.len() => {
+				trace!(target: LOG_TARGET, "Ignored block data already downloaded: {}", start);
+				return;
+			},
+			_ => (),
+		}
+
+		self.blocks.insert(
+			start,
+			BlockRangeState::Complete(
+				blocks.into_iter().map(|b| BlockData { origin: Some(who), block: b }).collect(),
+			),
+		);
+	}
+
+	/// Returns a set of block hashes that require a header download. The returned set is marked as
+	/// being downloaded.
+	pub fn needed_blocks(
+		&mut self,
+		who: PeerId,
+		count: u32,
+		peer_best: NumberFor<B>,
+		common: NumberFor<B>,
+		max_parallel: u32,
+		max_ahead: u32,
+	) -> Option<Range<NumberFor<B>>> {
+		if peer_best <= common {
+			// Bail out early
+			return None;
+		}
+		// First block number that we need to download
+		let first_different = common + <NumberFor<B>>::one();
+		let count = (count as u32).into();
+		let (mut range, downloading) = {
+			// Iterate through the ranges in `self.blocks` looking for a range to download
+			let mut downloading_iter = self.blocks.iter().peekable();
+			let mut prev: Option<(&NumberFor<B>, &BlockRangeState<B>)> = None;
+			loop {
+				let next = downloading_iter.next();
+				break match (prev, next) {
+					// If we are already downloading this range, request it from `max_parallel`
+					// peers (`max_parallel = 5` by default).
+					// Do not request already downloading range from peers with common number above
+					// the range start.
+					(Some((start, &BlockRangeState::Downloading { ref len, downloading })), _)
+						if downloading < max_parallel && *start >= first_different =>
+						(*start..*start + *len, downloading),
+					// If there is a gap between ranges requested, download this gap unless the peer
+					// has common number above the gap start
+					(Some((start, r)), Some((next_start, _)))
+						if *start + r.len() < *next_start &&
+							*start + r.len() >= first_different =>
+						(*start + r.len()..cmp::min(*next_start, *start + r.len() + count), 0),
+					// Download `count` blocks after the last range requested unless the peer
+					// has common number above this new range
+					(Some((start, r)), None) if *start + r.len() >= first_different =>
+						(*start + r.len()..*start + r.len() + count, 0),
+					// If there are no ranges currently requested, download `count` blocks after
+					// `common` number
+					(None, None) => (first_different..first_different + count, 0),
+					// If the first range starts above `common + 1`, download the gap at the start
+					(None, Some((start, _))) if *start > first_different =>
+						(first_different..cmp::min(first_different + count, *start), 0),
+					// Move on to the next range pair
+					_ => {
+						prev = next;
+						continue;
+					},
+				};
+			}
+		};
+		// crop to peers best
+		if range.start > peer_best {
+			trace!(target: LOG_TARGET, "Out of range for peer {} ({} vs {})", who, range.start, peer_best);
+			return None;
+		}
+		range.end = cmp::min(peer_best + One::one(), range.end);
+
+		if self
+			.blocks
+			.iter()
+			.next()
+			.map_or(false, |(n, _)| range.start > *n + max_ahead.into())
+		{
+			trace!(target: LOG_TARGET, "Too far ahead for peer {} ({})", who, range.start);
+			return None;
+		}
+
+		self.peer_requests.insert(who, range.start);
+		self.blocks.insert(
+			range.start,
+			BlockRangeState::Downloading {
+				len: range.end - range.start,
+				downloading: downloading + 1,
+			},
+		);
+		if range.end <= range.start {
+			panic!(
+				"Empty range {:?}, count={}, peer_best={}, common={}, blocks={:?}",
+				range, count, peer_best, common, self.blocks
+			);
+		}
+		Some(range)
+	}
+
+	/// Get a valid chain of blocks ordered in descending order and ready for importing into
+	/// the blockchain.
+	/// `from` is the maximum block number for the start of the range that we are interested in.
+	/// The function will return empty Vec if the first block ready is higher than `from`.
+	/// For each returned block hash `clear_queued` must be called at some later stage.
+	pub fn ready_blocks(&mut self, from: NumberFor<B>) -> Vec<BlockData<B>> {
+		let mut ready = Vec::new();
+
+		let mut prev = from;
+		for (&start, range_data) in &mut self.blocks {
+			if start > prev {
+				break;
+			}
+			let len = match range_data {
+				BlockRangeState::Complete(blocks) => {
+					let len = (blocks.len() as u32).into();
+					prev = start + len;
+					if let Some(BlockData { block, .. }) = blocks.first() {
+						self.queued_blocks
+							.insert(block.hash, (start, start + (blocks.len() as u32).into()));
+					}
+					// Remove all elements from `blocks` and add them to `ready`
+					ready.append(blocks);
+					len
+				},
+				BlockRangeState::Queued { .. } => continue,
+				_ => break,
+			};
+			*range_data = BlockRangeState::Queued { len };
+		}
+		trace!(target: LOG_TARGET, "{} blocks ready for import", ready.len());
+		ready
+	}
+
+	pub fn clear_queued(&mut self, hash: &B::Hash) {
+		if let Some((from, to)) = self.queued_blocks.remove(hash) {
+			let mut block_num = from;
+			while block_num < to {
+				self.blocks.remove(&block_num);
+				block_num += One::one();
+			}
+			trace!(target: LOG_TARGET, "Cleared blocks from {:?} to {:?}", from, to);
+		}
+	}
+
+	pub fn clear_peer_download(&mut self, who: &PeerId) {
+		if let Some(start) = self.peer_requests.remove(who) {
+			let remove = match self.blocks.get_mut(&start) {
+				Some(&mut BlockRangeState::Downloading { ref mut downloading, .. })
+					if *downloading > 1 =>
+				{
+					*downloading -= 1;
+					false
+				},
+				Some(&mut BlockRangeState::Downloading { .. }) => true,
+				_ => false,
+			};
+			if remove {
+				self.blocks.remove(&start);
+			}
+		}
+	}
+}
+
+#[cfg(test)]
+mod test {
+	use super::{BlockCollection, BlockData, BlockRangeState};
+	use pezsc_network_common::sync::message;
+	use pezsc_network_types::PeerId;
+	use pezsp_core::H256;
+	use pezsp_runtime::testing::{Block as RawBlock, MockCallU64, TestXt};
+
+	type Block = RawBlock<TestXt<MockCallU64, ()>>;
+
+	fn is_empty(bc: &BlockCollection<Block>) -> bool {
+		bc.blocks.is_empty() && bc.peer_requests.is_empty()
+	}
+
+	fn generate_blocks(n: usize) -> Vec<message::BlockData<Block>> {
+		(0..n)
+			.map(|_| message::generic::BlockData {
+				hash: H256::random(),
+				header: None,
+				body: None,
+				indexed_body: None,
+				message_queue: None,
+				receipt: None,
+				justification: None,
+				justifications: None,
+			})
+			.collect()
+	}
+
+	#[test]
+	fn create_clear() {
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+		bc.insert(1, generate_blocks(100), PeerId::random());
+		assert!(!is_empty(&bc));
+		bc.clear();
+		assert!(is_empty(&bc));
+	}
+
+	#[test]
+	fn insert_blocks() {
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+		let peer0 = PeerId::random();
+		let peer1 = PeerId::random();
+		let peer2 = PeerId::random();
+
+		let blocks = generate_blocks(150);
+		assert_eq!(bc.needed_blocks(peer0, 40, 150, 0, 1, 200), Some(1..41));
+		assert_eq!(bc.needed_blocks(peer1, 40, 150, 0, 1, 200), Some(41..81));
+		assert_eq!(bc.needed_blocks(peer2, 40, 150, 0, 1, 200), Some(81..121));
+
+		bc.clear_peer_download(&peer1);
+		bc.insert(41, blocks[41..81].to_vec(), peer1);
+		assert_eq!(bc.ready_blocks(1), vec![]);
+		assert_eq!(bc.needed_blocks(peer1, 40, 150, 0, 1, 200), Some(121..151));
+		bc.clear_peer_download(&peer0);
+		bc.insert(1, blocks[1..11].to_vec(), peer0);
+
+		assert_eq!(bc.needed_blocks(peer0, 40, 150, 0, 1, 200), Some(11..41));
+		assert_eq!(
+			bc.ready_blocks(1),
+			blocks[1..11]
+				.iter()
+				.map(|b| BlockData { block: b.clone(), origin: Some(peer0) })
+				.collect::<Vec<_>>()
+		);
+
+		bc.clear_peer_download(&peer0);
+		bc.insert(11, blocks[11..41].to_vec(), peer0);
+
+		let ready = bc.ready_blocks(12);
+		assert_eq!(
+			ready[..30],
+			blocks[11..41]
+				.iter()
+				.map(|b| BlockData { block: b.clone(), origin: Some(peer0) })
+				.collect::<Vec<_>>()[..]
+		);
+		assert_eq!(
+			ready[30..],
+			blocks[41..81]
+				.iter()
+				.map(|b| BlockData { block: b.clone(), origin: Some(peer1) })
+				.collect::<Vec<_>>()[..]
+		);
+
+		bc.clear_peer_download(&peer2);
+		assert_eq!(bc.needed_blocks(peer2, 40, 150, 80, 1, 200), Some(81..121));
+		bc.clear_peer_download(&peer2);
+		bc.insert(81, blocks[81..121].to_vec(), peer2);
+		bc.clear_peer_download(&peer1);
+		bc.insert(121, blocks[121..150].to_vec(), peer1);
+
+		assert_eq!(bc.ready_blocks(80), vec![]);
+		let ready = bc.ready_blocks(81);
+		assert_eq!(
+			ready[..40],
+			blocks[81..121]
+				.iter()
+				.map(|b| BlockData { block: b.clone(), origin: Some(peer2) })
+				.collect::<Vec<_>>()[..]
+		);
+		assert_eq!(
+			ready[40..],
+			blocks[121..150]
+				.iter()
+				.map(|b| BlockData { block: b.clone(), origin: Some(peer1) })
+				.collect::<Vec<_>>()[..]
+		);
+	}
+
+	#[test]
+	fn large_gap() {
+		let mut bc: BlockCollection<Block> = BlockCollection::new();
+		bc.blocks.insert(100, BlockRangeState::Downloading { len: 128, downloading: 1 });
+		let blocks = generate_blocks(10)
+			.into_iter()
+			.map(|b| BlockData { block: b, origin: None })
+			.collect();
+		bc.blocks.insert(114305, BlockRangeState::Complete(blocks));
+
+		let peer0 = PeerId::random();
+		assert_eq!(bc.needed_blocks(peer0, 128, 10000, 0, 1, 200), Some(1..100));
+		assert_eq!(bc.needed_blocks(peer0, 128, 10000, 0, 1, 200), None); // too far ahead
+		assert_eq!(
+			bc.needed_blocks(peer0, 128, 10000, 0, 1, 200000),
+			Some(100 + 128..100 + 128 + 128)
+		);
+	}
+
+	#[test]
+	fn no_duplicate_requests_on_fork() {
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+		let peer = PeerId::random();
+
+		let blocks = generate_blocks(10);
+
+		// count = 5, peer_best = 50, common = 39, max_parallel = 0, max_ahead = 200
+		assert_eq!(bc.needed_blocks(peer, 5, 50, 39, 0, 200), Some(40..45));
+
+		// got a response on the request for `40..45`
+		bc.clear_peer_download(&peer);
+		bc.insert(40, blocks[..5].to_vec(), peer);
+
+		// our "node" started on a fork, with its current best = 47, which is > common
+		let ready = bc.ready_blocks(48);
+		assert_eq!(
+			ready,
+			blocks[..5]
+				.iter()
+				.map(|b| BlockData { block: b.clone(), origin: Some(peer) })
+				.collect::<Vec<_>>()
+		);
+
+		assert_eq!(bc.needed_blocks(peer, 5, 50, 39, 0, 200), Some(45..50));
+	}
+
+	#[test]
+	fn clear_queued_subsequent_ranges() {
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+		let peer = PeerId::random();
+
+		let blocks = generate_blocks(10);
+
+		// Request 2 ranges
+		assert_eq!(bc.needed_blocks(peer, 5, 50, 39, 0, 200), Some(40..45));
+		assert_eq!(bc.needed_blocks(peer, 5, 50, 39, 0, 200), Some(45..50));
+
+		// got a response on the request for `40..50`
+		bc.clear_peer_download(&peer);
+		bc.insert(40, blocks.to_vec(), peer);
+
+		// request any blocks starting from 1000 or lower.
+		let ready = bc.ready_blocks(1000);
+		assert_eq!(
+			ready,
+			blocks
+				.iter()
+				.map(|b| BlockData { block: b.clone(), origin: Some(peer) })
+				.collect::<Vec<_>>()
+		);
+
+		bc.clear_queued(&blocks[0].hash);
+		assert!(bc.blocks.is_empty());
+		assert!(bc.queued_blocks.is_empty());
+	}
+
+	#[test]
+	fn downloaded_range_is_requested_from_max_parallel_peers() {
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+
+		let count = 5;
+		// identical ranges requested from 2 peers
+		let max_parallel = 2;
+		let max_ahead = 200;
+
+		let peer1 = PeerId::random();
+		let peer2 = PeerId::random();
+		let peer3 = PeerId::random();
+
+		// common for all peers
+		let best = 100;
+		let common = 10;
+
+		assert_eq!(
+			bc.needed_blocks(peer1, count, best, common, max_parallel, max_ahead),
+			Some(11..16)
+		);
+		assert_eq!(
+			bc.needed_blocks(peer2, count, best, common, max_parallel, max_ahead),
+			Some(11..16)
+		);
+		assert_eq!(
+			bc.needed_blocks(peer3, count, best, common, max_parallel, max_ahead),
+			Some(16..21)
+		);
+	}
+	#[test]
+	fn downloaded_range_not_requested_from_peers_with_higher_common_number() {
+		// A peer connects with a common number falling behind our best number
+		// (either a fork or lagging behind).
+		// We request a range from this peer starting at its common number + 1.
+		// Even though we have less than `max_parallel` downloads, we do not request
+		// this range from peers with a common number above the start of this range.
+
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+
+		let count = 5;
+		let max_parallel = 2;
+		let max_ahead = 200;
+
+		let peer1 = PeerId::random();
+		let peer1_best = 20;
+		let peer1_common = 10;
+
+		// `peer2` has first different above the start of the range downloaded from `peer1`
+		let peer2 = PeerId::random();
+		let peer2_best = 20;
+		let peer2_common = 11; // first_different = 12
+
+		assert_eq!(
+			bc.needed_blocks(peer1, count, peer1_best, peer1_common, max_parallel, max_ahead),
+			Some(11..16),
+		);
+		assert_eq!(
+			bc.needed_blocks(peer2, count, peer2_best, peer2_common, max_parallel, max_ahead),
+			Some(16..21),
+		);
+	}
+
+	#[test]
+	fn gap_above_common_number_requested() {
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+
+		let count = 5;
+		let best = 30;
+		// We need at least 3 ranges requested to have a gap, so to minimize the number of peers
+		// set `max_parallel = 1`
+		let max_parallel = 1;
+		let max_ahead = 200;
+
+		let peer1 = PeerId::random();
+		let peer2 = PeerId::random();
+		let peer3 = PeerId::random();
+
+		let common = 10;
+		assert_eq!(
+			bc.needed_blocks(peer1, count, best, common, max_parallel, max_ahead),
+			Some(11..16),
+		);
+		assert_eq!(
+			bc.needed_blocks(peer2, count, best, common, max_parallel, max_ahead),
+			Some(16..21),
+		);
+		assert_eq!(
+			bc.needed_blocks(peer3, count, best, common, max_parallel, max_ahead),
+			Some(21..26),
+		);
+
+		// For some reason there is now a gap at 16..21. We just disconnect `peer2`, but it might
+		// also happen that 16..21 received first and got imported if our best is actually >= 15.
+		bc.clear_peer_download(&peer2);
+
+		// Some peer connects with common number below the gap. The gap is requested from it.
+		assert_eq!(
+			bc.needed_blocks(peer2, count, best, common, max_parallel, max_ahead),
+			Some(16..21),
+		);
+	}
+
+	#[test]
+	fn gap_below_common_number_not_requested() {
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+
+		let count = 5;
+		let best = 30;
+		// We need at least 3 ranges requested to have a gap, so to minimize the number of peers
+		// set `max_parallel = 1`
+		let max_parallel = 1;
+		let max_ahead = 200;
+
+		let peer1 = PeerId::random();
+		let peer2 = PeerId::random();
+		let peer3 = PeerId::random();
+
+		let common = 10;
+		assert_eq!(
+			bc.needed_blocks(peer1, count, best, common, max_parallel, max_ahead),
+			Some(11..16),
+		);
+		assert_eq!(
+			bc.needed_blocks(peer2, count, best, common, max_parallel, max_ahead),
+			Some(16..21),
+		);
+		assert_eq!(
+			bc.needed_blocks(peer3, count, best, common, max_parallel, max_ahead),
+			Some(21..26),
+		);
+
+		// For some reason there is now a gap at 16..21. We just disconnect `peer2`, but it might
+		// also happen that 16..21 received first and got imported if our best is actually >= 15.
+		bc.clear_peer_download(&peer2);
+
+		// Some peer connects with common number above the gap. The gap is not requested from it.
+		let common = 23;
+		assert_eq!(
+			bc.needed_blocks(peer2, count, best, common, max_parallel, max_ahead),
+			Some(26..31), // not 16..21
+		);
+	}
+
+	#[test]
+	fn range_at_the_end_above_common_number_requested() {
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+
+		let count = 5;
+		let best = 30;
+		let max_parallel = 1;
+		let max_ahead = 200;
+
+		let peer1 = PeerId::random();
+		let peer2 = PeerId::random();
+
+		let common = 10;
+		assert_eq!(
+			bc.needed_blocks(peer1, count, best, common, max_parallel, max_ahead),
+			Some(11..16),
+		);
+		assert_eq!(
+			bc.needed_blocks(peer2, count, best, common, max_parallel, max_ahead),
+			Some(16..21),
+		);
+	}
+
+	#[test]
+	fn range_at_the_end_below_common_number_not_requested() {
+		let mut bc = BlockCollection::new();
+		assert!(is_empty(&bc));
+
+		let count = 5;
+		let best = 30;
+		let max_parallel = 1;
+		let max_ahead = 200;
+
+		let peer1 = PeerId::random();
+		let peer2 = PeerId::random();
+
+		let common = 10;
+		assert_eq!(
+			bc.needed_blocks(peer1, count, best, common, max_parallel, max_ahead),
+			Some(11..16),
+		);
+
+		let common = 20;
+		assert_eq!(
+			bc.needed_blocks(peer2, count, best, common, max_parallel, max_ahead),
+			Some(21..26), // not 16..21
+		);
+	}
+}

bizinikiwi/client/network/sync/src/futures_stream.rs

@@ -0,0 +1,134 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! A wrapper for [`FuturesUnordered`] that wakes the task up once a new future is pushed
+//! for it to be polled automatically. It's [`Stream`] never terminates.
+
+use futures::{stream::FuturesUnordered, Future, Stream, StreamExt};
+use std::{
+	pin::Pin,
+	task::{Context, Poll, Waker},
+};
+
+/// Wrapper around [`FuturesUnordered`] that wakes a task up automatically.
+pub struct FuturesStream<F> {
+	futures: FuturesUnordered<F>,
+	waker: Option<Waker>,
+}
+
+/// Surprizingly, `#[derive(Default)]` doesn't work on [`FuturesStream`].
+impl<F> Default for FuturesStream<F> {
+	fn default() -> FuturesStream<F> {
+		FuturesStream { futures: Default::default(), waker: None }
+	}
+}
+
+impl<F> FuturesStream<F> {
+	/// Push a future for processing.
+	pub fn push(&mut self, future: F) {
+		self.futures.push(future);
+
+		if let Some(waker) = self.waker.take() {
+			waker.wake();
+		}
+	}
+
+	/// The number of futures in the stream.
+	pub fn len(&self) -> usize {
+		self.futures.len()
+	}
+}
+
+impl<F: Future> Stream for FuturesStream<F> {
+	type Item = <F as Future>::Output;
+
+	fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+		let Poll::Ready(Some(result)) = self.futures.poll_next_unpin(cx) else {
+			self.waker = Some(cx.waker().clone());
+
+			return Poll::Pending;
+		};
+
+		Poll::Ready(Some(result))
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use futures::future::{BoxFuture, FutureExt};
+
+	/// [`Stream`] implementation for [`FuturesStream`] relies on the undocumented
+	/// feature that [`FuturesUnordered`] can be polled and repeatedly yield
+	/// `Poll::Ready(None)` before any futures are added into it.
+	#[tokio::test]
+	async fn empty_futures_unordered_can_be_polled() {
+		let mut unordered = FuturesUnordered::<BoxFuture<()>>::default();
+
+		futures::future::poll_fn(|cx| {
+			assert_eq!(unordered.poll_next_unpin(cx), Poll::Ready(None));
+			assert_eq!(unordered.poll_next_unpin(cx), Poll::Ready(None));
+
+			Poll::Ready(())
+		})
+		.await;
+	}
+
+	/// [`Stream`] implementation for [`FuturesStream`] relies on the undocumented
+	/// feature that [`FuturesUnordered`] can be polled and repeatedly yield
+	/// `Poll::Ready(None)` after all the futures in it have resolved.
+	#[tokio::test]
+	async fn deplenished_futures_unordered_can_be_polled() {
+		let mut unordered = FuturesUnordered::<BoxFuture<()>>::default();
+
+		unordered.push(futures::future::ready(()).boxed());
+		assert_eq!(unordered.next().await, Some(()));
+
+		futures::future::poll_fn(|cx| {
+			assert_eq!(unordered.poll_next_unpin(cx), Poll::Ready(None));
+			assert_eq!(unordered.poll_next_unpin(cx), Poll::Ready(None));
+
+			Poll::Ready(())
+		})
+		.await;
+	}
+
+	#[tokio::test]
+	async fn empty_futures_stream_yields_pending() {
+		let mut stream = FuturesStream::<BoxFuture<()>>::default();
+
+		futures::future::poll_fn(|cx| {
+			assert_eq!(stream.poll_next_unpin(cx), Poll::Pending);
+			Poll::Ready(())
+		})
+		.await;
+	}
+
+	#[tokio::test]
+	async fn futures_stream_resolves_futures_and_yields_pending() {
+		let mut stream = FuturesStream::default();
+		stream.push(futures::future::ready(17));
+
+		futures::future::poll_fn(|cx| {
+			assert_eq!(stream.poll_next_unpin(cx), Poll::Ready(Some(17)));
+			assert_eq!(stream.poll_next_unpin(cx), Poll::Pending);
+			Poll::Ready(())
+		})
+		.await;
+	}
+}

bizinikiwi/client/network/sync/src/justification_requests.rs

@@ -0,0 +1,679 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Justification requests scheduling. [`ExtraRequests`] manages requesting justifications
+//! from peers taking into account forks and their finalization (dropping pending requests
+//! that don't make sense after one of the forks is finalized).
+
+use crate::{
+	strategy::chain_sync::{PeerSync, PeerSyncState},
+	LOG_TARGET,
+};
+use fork_tree::ForkTree;
+use log::{debug, trace, warn};
+use prometheus_endpoint::{
+	prometheus::core::GenericGauge, register, GaugeVec, Opts, PrometheusError, Registry, U64,
+};
+use pezsc_network_types::PeerId;
+use pezsp_blockchain::Error as ClientError;
+use pezsp_runtime::traits::{Block as BlockT, NumberFor, Zero};
+use std::{
+	collections::{HashMap, HashSet, VecDeque},
+	time::{Duration, Instant},
+};
+
+// Time to wait before trying to get the same extra data from the same peer.
+const EXTRA_RETRY_WAIT: Duration = Duration::from_secs(10);
+
+/// Pending extra data request for the given block (hash and number).
+type ExtraRequest<B> = (<B as BlockT>::Hash, NumberFor<B>);
+
+#[derive(Debug)]
+struct Metrics {
+	pending: GenericGauge<U64>,
+	active: GenericGauge<U64>,
+	failed: GenericGauge<U64>,
+	importing: GenericGauge<U64>,
+}
+
+impl Metrics {
+	fn register(registry: &Registry) -> Result<Self, PrometheusError> {
+		let justifications = GaugeVec::<U64>::new(
+			Opts::new(
+				"bizinikiwi_sync_extra_justifications",
+				"Number of extra justifications requests",
+			),
+			&["status"],
+		)?;
+		let justifications = register(justifications, registry)?;
+
+		Ok(Self {
+			pending: justifications.with_label_values(&["pending"]),
+			active: justifications.with_label_values(&["active"]),
+			failed: justifications.with_label_values(&["failed"]),
+			importing: justifications.with_label_values(&["importing"]),
+		})
+	}
+}
+
+/// Manages pending block extra data (e.g. justification) requests.
+///
+/// Multiple extras may be requested for competing forks, or for the same branch
+/// at different (increasing) heights. This structure will guarantee that extras
+/// are fetched in-order, and that obsolete changes are pruned (when finalizing a
+/// competing fork).
+#[derive(Debug)]
+pub(crate) struct ExtraRequests<B: BlockT> {
+	tree: ForkTree<B::Hash, NumberFor<B>, ()>,
+	/// best finalized block number that we have seen since restart
+	best_seen_finalized_number: NumberFor<B>,
+	/// requests which have been queued for later processing
+	pending_requests: VecDeque<ExtraRequest<B>>,
+	/// requests which are currently underway to some peer
+	active_requests: HashMap<PeerId, ExtraRequest<B>>,
+	/// previous requests without response
+	failed_requests: HashMap<ExtraRequest<B>, Vec<(PeerId, Instant)>>,
+	/// successful requests
+	importing_requests: HashSet<ExtraRequest<B>>,
+	/// the name of this type of extra request (useful for logging.)
+	request_type_name: &'static str,
+	metrics: Option<Metrics>,
+}
+
+impl<B: BlockT> ExtraRequests<B> {
+	pub(crate) fn new(
+		request_type_name: &'static str,
+		metrics_registry: Option<&Registry>,
+	) -> Self {
+		Self {
+			tree: ForkTree::new(),
+			best_seen_finalized_number: Zero::zero(),
+			pending_requests: VecDeque::new(),
+			active_requests: HashMap::new(),
+			failed_requests: HashMap::new(),
+			importing_requests: HashSet::new(),
+			request_type_name,
+			metrics: metrics_registry.and_then(|registry| {
+				Metrics::register(registry)
+					.inspect_err(|error| {
+						log::error!(
+							target: LOG_TARGET,
+							"Failed to register `ExtraRequests` metrics {error}",
+						);
+					})
+					.ok()
+			}),
+		}
+	}
+
+	/// Reset all state as if returned from `new`.
+	pub(crate) fn reset(&mut self) {
+		self.tree = ForkTree::new();
+		self.pending_requests.clear();
+		self.active_requests.clear();
+		self.failed_requests.clear();
+
+		if let Some(metrics) = &self.metrics {
+			metrics.pending.set(0);
+			metrics.active.set(0);
+			metrics.failed.set(0);
+		}
+	}
+
+	/// Returns an iterator-like struct that yields peers which extra
+	/// requests can be sent to.
+	pub(crate) fn matcher(&mut self) -> Matcher<'_, B> {
+		Matcher::new(self)
+	}
+
+	/// Queue an extra data request to be considered by the `Matcher`.
+	pub(crate) fn schedule<F>(&mut self, request: ExtraRequest<B>, is_descendent_of: F)
+	where
+		F: Fn(&B::Hash, &B::Hash) -> Result<bool, ClientError>,
+	{
+		match self.tree.import(request.0, request.1, (), &is_descendent_of) {
+			Ok(true) => {
+				// this is a new root so we add it to the current `pending_requests`
+				self.pending_requests.push_back((request.0, request.1));
+				if let Some(metrics) = &self.metrics {
+					metrics.pending.inc();
+				}
+			},
+			Err(fork_tree::Error::Revert) => {
+				// we have finalized further than the given request, presumably
+				// by some other part of the system (not sync). we can safely
+				// ignore the `Revert` error.
+			},
+			Err(err) => {
+				debug!(target: LOG_TARGET, "Failed to insert request {:?} into tree: {}", request, err);
+			},
+			_ => (),
+		}
+	}
+
+	/// Retry any pending request if a peer disconnected.
+	pub(crate) fn peer_disconnected(&mut self, who: &PeerId) {
+		if let Some(request) = self.active_requests.remove(who) {
+			self.pending_requests.push_front(request);
+			if let Some(metrics) = &self.metrics {
+				metrics.active.dec();
+				metrics.pending.inc();
+			}
+		}
+	}
+
+	/// Processes the response for the request previously sent to the given peer.
+	pub(crate) fn on_response<R>(
+		&mut self,
+		who: PeerId,
+		resp: Option<R>,
+	) -> Option<(PeerId, B::Hash, NumberFor<B>, R)> {
+		// we assume that the request maps to the given response, this is
+		// currently enforced by the outer network protocol before passing on
+		// messages to chain sync.
+		if let Some(request) = self.active_requests.remove(&who) {
+			if let Some(metrics) = &self.metrics {
+				metrics.active.dec();
+			}
+
+			if let Some(r) = resp {
+				trace!(target: LOG_TARGET,
+					"Queuing import of {} from {:?} for {:?}",
+					self.request_type_name, who, request,
+				);
+
+				if self.importing_requests.insert(request) {
+					if let Some(metrics) = &self.metrics {
+						metrics.importing.inc();
+					}
+				}
+				return Some((who, request.0, request.1, r));
+			} else {
+				trace!(target: LOG_TARGET,
+					"Empty {} response from {:?} for {:?}",
+					self.request_type_name, who, request,
+				);
+			}
+			self.failed_requests.entry(request).or_default().push((who, Instant::now()));
+			self.pending_requests.push_front(request);
+			if let Some(metrics) = &self.metrics {
+				metrics.failed.set(self.failed_requests.len().try_into().unwrap_or(u64::MAX));
+				metrics.pending.inc();
+			}
+		} else {
+			trace!(target: LOG_TARGET,
+				"No active {} request to {:?}",
+				self.request_type_name, who,
+			);
+		}
+		None
+	}
+
+	/// Removes any pending extra requests for blocks lower than the given best finalized.
+	pub(crate) fn on_block_finalized<F>(
+		&mut self,
+		best_finalized_hash: &B::Hash,
+		best_finalized_number: NumberFor<B>,
+		is_descendent_of: F,
+	) -> Result<(), fork_tree::Error<ClientError>>
+	where
+		F: Fn(&B::Hash, &B::Hash) -> Result<bool, ClientError>,
+	{
+		let request = (*best_finalized_hash, best_finalized_number);
+
+		if self.try_finalize_root::<()>(request, Ok(request), false) {
+			return Ok(());
+		}
+
+		if best_finalized_number > self.best_seen_finalized_number {
+			// we receive finality notification only for the finalized branch head.
+			match self.tree.finalize_with_ancestors(
+				best_finalized_hash,
+				best_finalized_number,
+				&is_descendent_of,
+			) {
+				Err(fork_tree::Error::Revert) => {
+					// we might have finalized further already in which case we
+					// will get a `Revert` error which we can safely ignore.
+				},
+				Err(err) => return Err(err),
+				Ok(_) => {},
+			}
+
+			self.best_seen_finalized_number = best_finalized_number;
+		}
+
+		let roots = self.tree.roots().collect::<HashSet<_>>();
+
+		self.pending_requests.retain(|(h, n)| roots.contains(&(h, n, &())));
+		self.active_requests.retain(|_, (h, n)| roots.contains(&(h, n, &())));
+		self.failed_requests.retain(|(h, n), _| roots.contains(&(h, n, &())));
+		if let Some(metrics) = &self.metrics {
+			metrics.pending.set(self.pending_requests.len().try_into().unwrap_or(u64::MAX));
+			metrics.active.set(self.active_requests.len().try_into().unwrap_or(u64::MAX));
+			metrics.failed.set(self.failed_requests.len().try_into().unwrap_or(u64::MAX));
+		}
+
+		Ok(())
+	}
+
+	/// Try to finalize pending root.
+	///
+	/// Returns true if import of this request has been scheduled.
+	pub(crate) fn try_finalize_root<E>(
+		&mut self,
+		request: ExtraRequest<B>,
+		result: Result<ExtraRequest<B>, E>,
+		reschedule_on_failure: bool,
+	) -> bool {
+		if !self.importing_requests.remove(&request) {
+			return false;
+		}
+		if let Some(metrics) = &self.metrics {
+			metrics.importing.dec();
+		}
+
+		let (finalized_hash, finalized_number) = match result {
+			Ok(req) => (req.0, req.1),
+			Err(_) => {
+				if reschedule_on_failure {
+					self.pending_requests.push_front(request);
+					if let Some(metrics) = &self.metrics {
+						metrics.pending.inc();
+					}
+				}
+				return true;
+			},
+		};
+
+		if self.tree.finalize_root(&finalized_hash).is_none() {
+			warn!(target: LOG_TARGET,
+				"‼️ Imported {:?} {:?} which isn't a root in the tree: {:?}",
+				finalized_hash, finalized_number, self.tree.roots().collect::<Vec<_>>()
+			);
+			return true;
+		}
+
+		self.failed_requests.clear();
+		self.active_requests.clear();
+		self.pending_requests.clear();
+		self.pending_requests.extend(self.tree.roots().map(|(&h, &n, _)| (h, n)));
+		if let Some(metrics) = &self.metrics {
+			metrics.failed.set(0);
+			metrics.active.set(0);
+			metrics.pending.set(self.pending_requests.len().try_into().unwrap_or(u64::MAX));
+		}
+		self.best_seen_finalized_number = finalized_number;
+
+		true
+	}
+
+	/// Returns an iterator over all active (in-flight) requests and associated peer id.
+	#[cfg(test)]
+	pub(crate) fn active_requests(&self) -> impl Iterator<Item = (&PeerId, &ExtraRequest<B>)> {
+		self.active_requests.iter()
+	}
+
+	/// Returns an iterator over all scheduled pending requests.
+	#[cfg(test)]
+	pub(crate) fn pending_requests(&self) -> impl Iterator<Item = &ExtraRequest<B>> {
+		self.pending_requests.iter()
+	}
+}
+
+/// Matches peers with pending extra requests.
+#[derive(Debug)]
+pub(crate) struct Matcher<'a, B: BlockT> {
+	/// Length of pending requests collection.
+	/// Used to ensure we do not loop more than once over all pending requests.
+	remaining: usize,
+	extras: &'a mut ExtraRequests<B>,
+}
+
+impl<'a, B: BlockT> Matcher<'a, B> {
+	fn new(extras: &'a mut ExtraRequests<B>) -> Self {
+		Self { remaining: extras.pending_requests.len(), extras }
+	}
+
+	/// Finds a peer to which a pending request can be sent.
+	///
+	/// Peers are filtered according to the current known best block (i.e. we won't
+	/// send an extra request for block #10 to a peer at block #2), and we also
+	/// throttle requests to the same peer if a previous request yielded no results.
+	///
+	/// This method returns as soon as it finds a peer that should be able to answer
+	/// our request. If no request is pending or no peer can handle it, `None` is
+	/// returned instead.
+	///
+	/// # Note
+	///
+	/// The returned `PeerId` (if any) is guaranteed to come from the given `peers`
+	/// argument.
+	pub(crate) fn next(
+		&mut self,
+		peers: &HashMap<PeerId, PeerSync<B>>,
+	) -> Option<(PeerId, ExtraRequest<B>)> {
+		if self.remaining == 0 {
+			return None;
+		}
+
+		// clean up previously failed requests so we can retry again
+		for requests in self.extras.failed_requests.values_mut() {
+			requests.retain(|(_, instant)| instant.elapsed() < EXTRA_RETRY_WAIT);
+		}
+		if let Some(metrics) = &self.extras.metrics {
+			metrics
+				.failed
+				.set(self.extras.failed_requests.len().try_into().unwrap_or(u64::MAX));
+		}
+
+		while let Some(request) = self.extras.pending_requests.pop_front() {
+			if let Some(metrics) = &self.extras.metrics {
+				metrics.pending.dec();
+			}
+
+			for (peer, sync) in
+				peers.iter().filter(|(_, sync)| sync.state == PeerSyncState::Available)
+			{
+				// only ask peers that have synced at least up to the block number that we're asking
+				// the extra for
+				if sync.best_number < request.1 {
+					continue;
+				}
+				// don't request to any peers that already have pending requests
+				if self.extras.active_requests.contains_key(peer) {
+					continue;
+				}
+				// only ask if the same request has not failed for this peer before
+				if self
+					.extras
+					.failed_requests
+					.get(&request)
+					.map(|rr| rr.iter().any(|i| &i.0 == peer))
+					.unwrap_or(false)
+				{
+					continue;
+				}
+				self.extras.active_requests.insert(*peer, request);
+				if let Some(metrics) = &self.extras.metrics {
+					metrics.active.inc();
+				}
+
+				trace!(target: LOG_TARGET,
+					"Sending {} request to {:?} for {:?}",
+					self.extras.request_type_name, peer, request,
+				);
+
+				return Some((*peer, request));
+			}
+
+			self.extras.pending_requests.push_back(request);
+			if let Some(metrics) = &self.extras.metrics {
+				metrics.pending.inc();
+			}
+			self.remaining -= 1;
+
+			if self.remaining == 0 {
+				break;
+			}
+		}
+
+		None
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::strategy::chain_sync::PeerSync;
+	use quickcheck::{Arbitrary, Gen, QuickCheck};
+	use pezsp_blockchain::Error as ClientError;
+	use pezsp_test_primitives::{Block, BlockNumber, Hash};
+	use std::collections::{HashMap, HashSet};
+
+	#[test]
+	fn requests_are_processed_in_order() {
+		fn property(mut peers: ArbitraryPeers) {
+			let mut requests = ExtraRequests::<Block>::new("test", None);
+
+			let num_peers_available =
+				peers.0.values().filter(|s| s.state == PeerSyncState::Available).count();
+
+			for i in 0..num_peers_available {
+				requests.schedule((Hash::random(), i as u64), |a, b| Ok(a[0] >= b[0]))
+			}
+
+			let pending = requests.pending_requests.clone();
+			let mut m = requests.matcher();
+
+			for p in &pending {
+				let (peer, r) = m.next(&peers.0).unwrap();
+				assert_eq!(p, &r);
+				peers.0.get_mut(&peer).unwrap().state =
+					PeerSyncState::DownloadingJustification(r.0);
+			}
+		}
+
+		QuickCheck::new().quickcheck(property as fn(ArbitraryPeers))
+	}
+
+	#[test]
+	fn new_roots_schedule_new_request() {
+		fn property(data: Vec<BlockNumber>) {
+			let mut requests = ExtraRequests::<Block>::new("test", None);
+			for (i, number) in data.into_iter().enumerate() {
+				let hash = [i as u8; 32].into();
+				let pending = requests.pending_requests.len();
+				let is_root = requests.tree.roots().any(|(&h, &n, _)| hash == h && number == n);
+				requests.schedule((hash, number), |a, b| Ok(a[0] >= b[0]));
+				if !is_root {
+					assert_eq!(1 + pending, requests.pending_requests.len())
+				}
+			}
+		}
+		QuickCheck::new().quickcheck(property as fn(Vec<BlockNumber>))
+	}
+
+	#[test]
+	fn disconnecting_implies_rescheduling() {
+		fn property(mut peers: ArbitraryPeers) -> bool {
+			let mut requests = ExtraRequests::<Block>::new("test", None);
+
+			let num_peers_available =
+				peers.0.values().filter(|s| s.state == PeerSyncState::Available).count();
+
+			for i in 0..num_peers_available {
+				requests.schedule((Hash::random(), i as u64), |a, b| Ok(a[0] >= b[0]))
+			}
+
+			let mut m = requests.matcher();
+			while let Some((peer, r)) = m.next(&peers.0) {
+				peers.0.get_mut(&peer).unwrap().state =
+					PeerSyncState::DownloadingJustification(r.0);
+			}
+
+			assert!(requests.pending_requests.is_empty());
+
+			let active_peers = requests.active_requests.keys().cloned().collect::<Vec<_>>();
+			let previously_active =
+				requests.active_requests.values().cloned().collect::<HashSet<_>>();
+
+			for peer in &active_peers {
+				requests.peer_disconnected(peer)
+			}
+
+			assert!(requests.active_requests.is_empty());
+
+			previously_active == requests.pending_requests.iter().cloned().collect::<HashSet<_>>()
+		}
+
+		QuickCheck::new().quickcheck(property as fn(ArbitraryPeers) -> bool)
+	}
+
+	#[test]
+	fn no_response_reschedules() {
+		fn property(mut peers: ArbitraryPeers) {
+			let mut requests = ExtraRequests::<Block>::new("test", None);
+
+			let num_peers_available =
+				peers.0.values().filter(|s| s.state == PeerSyncState::Available).count();
+
+			for i in 0..num_peers_available {
+				requests.schedule((Hash::random(), i as u64), |a, b| Ok(a[0] >= b[0]))
+			}
+
+			let mut m = requests.matcher();
+			while let Some((peer, r)) = m.next(&peers.0) {
+				peers.0.get_mut(&peer).unwrap().state =
+					PeerSyncState::DownloadingJustification(r.0);
+			}
+
+			let active = requests.active_requests.iter().map(|(&p, &r)| (p, r)).collect::<Vec<_>>();
+
+			for (peer, req) in &active {
+				assert!(requests.failed_requests.get(req).is_none());
+				assert!(!requests.pending_requests.contains(req));
+				assert!(requests.on_response::<()>(*peer, None).is_none());
+				assert!(requests.pending_requests.contains(req));
+				assert_eq!(
+					1,
+					requests
+						.failed_requests
+						.get(req)
+						.unwrap()
+						.iter()
+						.filter(|(p, _)| p == peer)
+						.count()
+				)
+			}
+		}
+
+		QuickCheck::new().quickcheck(property as fn(ArbitraryPeers))
+	}
+
+	#[test]
+	fn request_is_rescheduled_when_earlier_block_is_finalized() {
+		pezsp_tracing::try_init_simple();
+
+		let mut finality_proofs = ExtraRequests::<Block>::new("test", None);
+
+		let hash4 = [4; 32].into();
+		let hash5 = [5; 32].into();
+		let hash6 = [6; 32].into();
+		let hash7 = [7; 32].into();
+
+		fn is_descendent_of(base: &Hash, target: &Hash) -> Result<bool, ClientError> {
+			Ok(target[0] >= base[0])
+		}
+
+		// make #4 last finalized block
+		finality_proofs.tree.import(hash4, 4, (), &is_descendent_of).unwrap();
+		finality_proofs.tree.finalize_root(&hash4);
+
+		// schedule request for #6
+		finality_proofs.schedule((hash6, 6), is_descendent_of);
+
+		// receive finality proof for #5
+		finality_proofs.importing_requests.insert((hash6, 6));
+		finality_proofs.on_block_finalized(&hash5, 5, is_descendent_of).unwrap();
+		finality_proofs.try_finalize_root::<()>((hash6, 6), Ok((hash5, 5)), true);
+
+		// ensure that request for #6 is still pending
+		assert_eq!(finality_proofs.pending_requests.iter().collect::<Vec<_>>(), vec![&(hash6, 6)]);
+
+		// receive finality proof for #7
+		finality_proofs.importing_requests.insert((hash6, 6));
+		finality_proofs.on_block_finalized(&hash6, 6, is_descendent_of).unwrap();
+		finality_proofs.on_block_finalized(&hash7, 7, is_descendent_of).unwrap();
+		finality_proofs.try_finalize_root::<()>((hash6, 6), Ok((hash7, 7)), true);
+
+		// ensure that there's no request for #6
+		assert_eq!(
+			finality_proofs.pending_requests.iter().collect::<Vec<_>>(),
+			Vec::<&(Hash, u64)>::new()
+		);
+	}
+
+	#[test]
+	fn ancestor_roots_are_finalized_when_finality_notification_is_missed() {
+		let mut finality_proofs = ExtraRequests::<Block>::new("test", None);
+
+		let hash4 = [4; 32].into();
+		let hash5 = [5; 32].into();
+
+		fn is_descendent_of(base: &Hash, target: &Hash) -> Result<bool, ClientError> {
+			Ok(target[0] >= base[0])
+		}
+
+		// schedule request for #4
+		finality_proofs.schedule((hash4, 4), is_descendent_of);
+
+		// receive finality notification for #5 (missing notification for #4!!!)
+		finality_proofs.importing_requests.insert((hash4, 5));
+		finality_proofs.on_block_finalized(&hash5, 5, is_descendent_of).unwrap();
+		assert_eq!(finality_proofs.tree.roots().count(), 0);
+	}
+
+	// Some Arbitrary instances to allow easy construction of random peer sets:
+
+	#[derive(Debug, Clone)]
+	struct ArbitraryPeerSyncState(PeerSyncState<Block>);
+
+	impl Arbitrary for ArbitraryPeerSyncState {
+		fn arbitrary(g: &mut Gen) -> Self {
+			let s = match u8::arbitrary(g) % 4 {
+				0 => PeerSyncState::Available,
+				// TODO: 1 => PeerSyncState::AncestorSearch(g.gen(), AncestorSearchState<B>),
+				1 => PeerSyncState::DownloadingNew(BlockNumber::arbitrary(g)),
+				2 => PeerSyncState::DownloadingStale(Hash::random()),
+				_ => PeerSyncState::DownloadingJustification(Hash::random()),
+			};
+			ArbitraryPeerSyncState(s)
+		}
+	}
+
+	#[derive(Debug, Clone)]
+	struct ArbitraryPeerSync(PeerSync<Block>);
+
+	impl Arbitrary for ArbitraryPeerSync {
+		fn arbitrary(g: &mut Gen) -> Self {
+			let ps = PeerSync {
+				peer_id: PeerId::random(),
+				common_number: u64::arbitrary(g),
+				best_hash: Hash::random(),
+				best_number: u64::arbitrary(g),
+				state: ArbitraryPeerSyncState::arbitrary(g).0,
+			};
+			ArbitraryPeerSync(ps)
+		}
+	}
+
+	#[derive(Debug, Clone)]
+	struct ArbitraryPeers(HashMap<PeerId, PeerSync<Block>>);
+
+	impl Arbitrary for ArbitraryPeers {
+		fn arbitrary(g: &mut Gen) -> Self {
+			let mut peers = HashMap::with_capacity(g.size());
+			for _ in 0..g.size() {
+				let ps = ArbitraryPeerSync::arbitrary(g).0;
+				peers.insert(ps.peer_id, ps);
+			}
+			ArbitraryPeers(peers)
+		}
+	}
+}

bizinikiwi/client/network/sync/src/lib.rs

@@ -0,0 +1,44 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Blockchain syncing implementation in Bizinikiwi.
+
+pub use schema::v1::*;
+pub use service::syncing_service::SyncingService;
+pub use strategy::warp::{WarpSyncConfig, WarpSyncPhase, WarpSyncProgress};
+pub use types::{SyncEvent, SyncEventStream, SyncState, SyncStatus, SyncStatusProvider};
+
+mod block_announce_validator;
+mod futures_stream;
+mod justification_requests;
+mod pending_responses;
+mod schema;
+pub mod types;
+
+pub mod block_relay_protocol;
+pub mod block_request_handler;
+pub mod blocks;
+pub mod engine;
+pub mod mock;
+pub mod service;
+pub mod state_request_handler;
+pub mod strategy;
+pub mod warp_request_handler;
+
+/// Log target for this crate.
+const LOG_TARGET: &str = "sync";

bizinikiwi/client/network/sync/src/mock.rs

@@ -0,0 +1,48 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Contains mock implementations of `ChainSync` and 'BlockDownloader'.
+
+use crate::block_relay_protocol::{BlockDownloader as BlockDownloaderT, BlockResponseError};
+
+use futures::channel::oneshot;
+use pezsc_network::{ProtocolName, RequestFailure};
+use pezsc_network_common::sync::message::{BlockData, BlockRequest};
+use pezsc_network_types::PeerId;
+use pezsp_runtime::traits::Block as BlockT;
+
+mockall::mock! {
+	#[derive(Debug)]
+	pub BlockDownloader<Block: BlockT> {}
+
+	#[async_trait::async_trait]
+	impl<Block: BlockT> BlockDownloaderT<Block> for BlockDownloader<Block> {
+		fn protocol_name(&self) -> &ProtocolName;
+
+		async fn download_blocks(
+			&self,
+			who: PeerId,
+			request: BlockRequest<Block>,
+		) -> Result<Result<(Vec<u8>, ProtocolName), RequestFailure>, oneshot::Canceled>;
+		fn block_response_into_blocks(
+			&self,
+			request: &BlockRequest<Block>,
+			response: Vec<u8>,
+		) -> Result<Vec<BlockData<Block>>, BlockResponseError>;
+	}
+}

bizinikiwi/client/network/sync/src/pending_responses.rs

@@ -0,0 +1,133 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! [`PendingResponses`] is responsible for keeping track of pending responses and
+//! polling them. [`Stream`] implemented by [`PendingResponses`] never terminates.
+
+use crate::{strategy::StrategyKey, LOG_TARGET};
+use futures::{
+	channel::oneshot,
+	future::BoxFuture,
+	stream::{BoxStream, FusedStream, Stream},
+	FutureExt, StreamExt,
+};
+use log::error;
+use std::any::Any;
+
+use pezsc_network::{request_responses::RequestFailure, types::ProtocolName};
+use pezsc_network_types::PeerId;
+use std::task::{Context, Poll, Waker};
+use tokio_stream::StreamMap;
+
+/// Response result.
+type ResponseResult =
+	Result<Result<(Box<dyn Any + Send>, ProtocolName), RequestFailure>, oneshot::Canceled>;
+
+/// A future yielding [`ResponseResult`].
+pub(crate) type ResponseFuture = BoxFuture<'static, ResponseResult>;
+
+/// An event we receive once a pending response future resolves.
+pub(crate) struct ResponseEvent {
+	pub peer_id: PeerId,
+	pub key: StrategyKey,
+	pub response: ResponseResult,
+}
+
+/// Stream taking care of polling pending responses.
+pub(crate) struct PendingResponses {
+	/// Pending responses
+	pending_responses: StreamMap<(PeerId, StrategyKey), BoxStream<'static, ResponseResult>>,
+	/// Waker to implement never terminating stream
+	waker: Option<Waker>,
+}
+
+impl PendingResponses {
+	pub fn new() -> Self {
+		Self { pending_responses: StreamMap::new(), waker: None }
+	}
+
+	pub fn insert(&mut self, peer_id: PeerId, key: StrategyKey, response_future: ResponseFuture) {
+		if self
+			.pending_responses
+			.insert((peer_id, key), Box::pin(response_future.into_stream()))
+			.is_some()
+		{
+			error!(
+				target: LOG_TARGET,
+				"Discarded pending response from peer {peer_id}, strategy key: {key:?}.",
+			);
+			debug_assert!(false);
+		}
+
+		if let Some(waker) = self.waker.take() {
+			waker.wake();
+		}
+	}
+
+	pub fn remove(&mut self, peer_id: PeerId, key: StrategyKey) -> bool {
+		self.pending_responses.remove(&(peer_id, key)).is_some()
+	}
+
+	pub fn remove_all(&mut self, peer_id: &PeerId) {
+		let to_remove = self
+			.pending_responses
+			.keys()
+			.filter(|(peer, _key)| peer == peer_id)
+			.cloned()
+			.collect::<Vec<_>>();
+		to_remove.iter().for_each(|k| {
+			self.pending_responses.remove(k);
+		});
+	}
+
+	pub fn len(&self) -> usize {
+		self.pending_responses.len()
+	}
+}
+
+impl Stream for PendingResponses {
+	type Item = ResponseEvent;
+
+	fn poll_next(
+		mut self: std::pin::Pin<&mut Self>,
+		cx: &mut Context<'_>,
+	) -> Poll<Option<Self::Item>> {
+		match self.pending_responses.poll_next_unpin(cx) {
+			Poll::Ready(Some(((peer_id, key), response))) => {
+				// We need to manually remove the stream, because `StreamMap` doesn't know yet that
+				// it's going to yield `None`, so may not remove it before the next request is made
+				// to the same peer.
+				self.pending_responses.remove(&(peer_id, key));
+
+				Poll::Ready(Some(ResponseEvent { peer_id, key, response }))
+			},
+			Poll::Ready(None) | Poll::Pending => {
+				self.waker = Some(cx.waker().clone());
+
+				Poll::Pending
+			},
+		}
+	}
+}
+
+// As [`PendingResponses`] never terminates, we can easily implement [`FusedStream`] for it.
+impl FusedStream for PendingResponses {
+	fn is_terminated(&self) -> bool {
+		false
+	}
+}

bizinikiwi/client/network/sync/src/schema.rs

@@ -0,0 +1,23 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Include sources generated from protobuf definitions.
+
+pub(crate) mod v1 {
+	include!(concat!(env!("OUT_DIR"), "/api.v1.rs"));
+}

bizinikiwi/client/network/sync/src/schema/api.v1.proto

@@ -0,0 +1,106 @@
+// Schema definition for block request/response messages.
+
+syntax = "proto3";
+
+package api.v1;
+
+// Block enumeration direction.
+enum Direction {
+	// Enumerate in ascending order (from child to parent).
+	Ascending = 0;
+	// Enumerate in descending order (from parent to canonical child).
+	Descending = 1;
+}
+
+// Request block data from a peer.
+message BlockRequest {
+	// Bits of block data to request.
+	uint32 fields = 1;
+	// Start from this block.
+	oneof from_block {
+		// Start with given hash.
+		bytes hash = 2;
+		// Start with given block number.
+		bytes number = 3;
+	}
+	// Sequence direction.
+	// If missing, should be interpreted as "Ascending".
+	Direction direction = 5;
+	// Maximum number of blocks to return. An implementation defined maximum is used when unspecified.
+	uint32 max_blocks = 6; // optional
+	// Indicate to the receiver that we support multiple justifications. If the responder also
+	// supports this it will populate the multiple justifications field in `BlockData` instead of
+	// the single justification field.
+	bool support_multiple_justifications = 7; // optional
+}
+
+// Response to `BlockRequest`
+message BlockResponse {
+	// Block data for the requested sequence.
+	repeated BlockData blocks = 1;
+}
+
+// Block data sent in the response.
+message BlockData {
+	// Block header hash.
+	bytes hash = 1;
+	// Block header if requested.
+	bytes header = 2; // optional
+	// Block body if requested.
+	repeated bytes body = 3; // optional
+	// Block receipt if requested.
+	bytes receipt = 4; // optional
+	// Block message queue if requested.
+	bytes message_queue = 5; // optional
+	// Justification if requested.
+	bytes justification = 6; // optional
+	// True if justification should be treated as present but empty.
+	// This hack is unfortunately necessary because shortcomings in the protobuf format otherwise
+	// doesn't make in possible to differentiate between a lack of justification and an empty
+	// justification.
+	bool is_empty_justification = 7; // optional, false if absent
+	// Justifications if requested.
+	// Unlike the field for a single justification, this field does not required an associated
+	// boolean to differentiate between the lack of justifications and empty justification(s). This
+	// is because empty justifications, like all justifications, are paired with a non-empty
+	// consensus engine ID.
+	bytes justifications = 8; // optional
+	// Indexed block body if requestd.
+	repeated bytes indexed_body = 9; // optional
+}
+
+// Request storage data from a peer.
+message StateRequest {
+	// Block header hash.
+	bytes block = 1;
+	// Start from this key.
+	// Multiple keys used for nested state start.
+	repeated bytes start = 2; // optional
+	// if 'true' indicates that response should contain raw key-values, rather than proof.
+	bool no_proof = 3;
+}
+
+message StateResponse {
+	// A collection of keys-values states. Only populated if `no_proof` is `true`
+	repeated KeyValueStateEntry entries = 1;
+	// If `no_proof` is false in request, this contains proof nodes.
+	bytes proof = 2;
+}
+
+// A key value state.
+message KeyValueStateEntry {
+	// Root of for this level, empty length bytes
+	// if top level.
+	bytes state_root = 1;
+	// A collection of keys-values.
+	repeated StateEntry entries = 2;
+	// Set to true when there are no more keys to return.
+	bool complete = 3;
+}
+
+// A key-value pair.
+message StateEntry {
+	bytes key = 1;
+	bytes value = 2;
+}
+

bizinikiwi/client/network/sync/src/service/mock.rs

@@ -0,0 +1,134 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use futures::channel::oneshot;
+
+use pezsc_consensus::{BlockImportError, BlockImportStatus};
+use pezsc_network::{
+	config::MultiaddrWithPeerId,
+	request_responses::{IfDisconnected, RequestFailure},
+	types::ProtocolName,
+	NetworkPeers, NetworkRequest, NetworkSyncForkRequest, ReputationChange,
+};
+use pezsc_network_common::role::ObservedRole;
+use pezsc_network_types::{multiaddr::Multiaddr, PeerId};
+use pezsp_runtime::traits::{Block as BlockT, NumberFor};
+
+use std::collections::HashSet;
+
+mockall::mock! {
+	pub ChainSyncInterface<B: BlockT> {
+		pub fn justification_sync_link_request_justification(&self, hash: &B::Hash, number: NumberFor<B>);
+		pub fn justification_sync_link_clear_justification_requests(&self);
+	}
+
+	impl<B: BlockT + 'static> NetworkSyncForkRequest<B::Hash, NumberFor<B>>
+		for ChainSyncInterface<B>
+	{
+		fn set_sync_fork_request(&self, peers: Vec<PeerId>, hash: B::Hash, number: NumberFor<B>);
+	}
+
+	impl<B: BlockT> pezsc_consensus::Link<B> for ChainSyncInterface<B> {
+		fn blocks_processed(
+			&self,
+			imported: usize,
+			count: usize,
+			results: Vec<(Result<BlockImportStatus<NumberFor<B>>, BlockImportError>, B::Hash)>,
+		);
+		fn justification_imported(
+			&self,
+			who: PeerId,
+			hash: &B::Hash,
+			number: NumberFor<B>,
+			import_result: pezsc_consensus::JustificationImportResult,
+		);
+		fn request_justification(&self, hash: &B::Hash, number: NumberFor<B>);
+	}
+}
+
+impl<B: BlockT> pezsc_consensus::JustificationSyncLink<B> for MockChainSyncInterface<B> {
+	fn request_justification(&self, hash: &B::Hash, number: NumberFor<B>) {
+		self.justification_sync_link_request_justification(hash, number);
+	}
+
+	fn clear_justification_requests(&self) {
+		self.justification_sync_link_clear_justification_requests();
+	}
+}
+
+mockall::mock! {
+	pub NetworkServiceHandle {}
+}
+
+// Mocked `Network` for `ChainSync`-related tests
+mockall::mock! {
+	pub Network {}
+
+	#[async_trait::async_trait]
+	impl NetworkPeers for Network {
+		fn set_authorized_peers(&self, peers: HashSet<PeerId>);
+		fn set_authorized_only(&self, reserved_only: bool);
+		fn add_known_address(&self, peer_id: PeerId, addr: Multiaddr);
+		fn report_peer(&self, peer_id: PeerId, cost_benefit: ReputationChange);
+		fn peer_reputation(&self, peer_id: &PeerId) -> i32;
+		fn disconnect_peer(&self, peer_id: PeerId, protocol: ProtocolName);
+		fn accept_unreserved_peers(&self);
+		fn deny_unreserved_peers(&self);
+		fn add_reserved_peer(&self, peer: MultiaddrWithPeerId) -> Result<(), String>;
+		fn remove_reserved_peer(&self, peer_id: PeerId);
+		fn set_reserved_peers(
+			&self,
+			protocol: ProtocolName,
+			peers: HashSet<Multiaddr>,
+		) -> Result<(), String>;
+		fn add_peers_to_reserved_set(
+			&self,
+			protocol: ProtocolName,
+			peers: HashSet<Multiaddr>,
+		) -> Result<(), String>;
+		fn remove_peers_from_reserved_set(
+			&self,
+			protocol: ProtocolName,
+			peers: Vec<PeerId>
+		) -> Result<(), String>;
+		fn sync_num_connected(&self) -> usize;
+		fn peer_role(&self, peer_id: PeerId, handshake: Vec<u8>) -> Option<ObservedRole>;
+		async fn reserved_peers(&self) -> Result<Vec<pezsc_network_types::PeerId>, ()>;
+	}
+
+	#[async_trait::async_trait]
+	impl NetworkRequest for Network {
+		async fn request(
+			&self,
+			target: PeerId,
+			protocol: ProtocolName,
+			request: Vec<u8>,
+			fallback_request: Option<(Vec<u8>, ProtocolName)>,
+			connect: IfDisconnected,
+		) -> Result<(Vec<u8>, ProtocolName), RequestFailure>;
+		fn start_request(
+			&self,
+			target: PeerId,
+			protocol: ProtocolName,
+			request: Vec<u8>,
+			fallback_request: Option<(Vec<u8>, ProtocolName)>,
+			tx: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+			connect: IfDisconnected,
+		);
+	}
+}

bizinikiwi/client/network/sync/src/service/mod.rs

@@ -0,0 +1,23 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! `SyncingEngine`-related service code
+
+pub mod mock;
+pub mod network;
+pub mod syncing_service;

bizinikiwi/client/network/sync/src/service/network.rs

@@ -0,0 +1,169 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use futures::{channel::oneshot, StreamExt};
+use pezsc_network_types::PeerId;
+
+use pezsc_network::{
+	request_responses::{IfDisconnected, RequestFailure},
+	types::ProtocolName,
+	NetworkPeers, NetworkRequest, ReputationChange,
+};
+use pezsc_utils::mpsc::{tracing_unbounded, TracingUnboundedReceiver, TracingUnboundedSender};
+
+use std::sync::Arc;
+
+/// Network-related services required by `sc-network-sync`
+pub trait Network: NetworkPeers + NetworkRequest {}
+
+impl<T> Network for T where T: NetworkPeers + NetworkRequest {}
+
+/// Network service provider for `ChainSync`
+///
+/// It runs as an asynchronous task and listens to commands coming from `ChainSync` and
+/// calls the `NetworkService` on its behalf.
+pub struct NetworkServiceProvider {
+	rx: TracingUnboundedReceiver<ToServiceCommand>,
+	handle: NetworkServiceHandle,
+}
+
+/// Commands that `ChainSync` wishes to send to `NetworkService`
+#[derive(Debug)]
+pub enum ToServiceCommand {
+	/// Call `NetworkPeers::disconnect_peer()`
+	DisconnectPeer(PeerId, ProtocolName),
+
+	/// Call `NetworkPeers::report_peer()`
+	ReportPeer(PeerId, ReputationChange),
+
+	/// Call `NetworkRequest::start_request()`
+	StartRequest(
+		PeerId,
+		ProtocolName,
+		Vec<u8>,
+		oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+		IfDisconnected,
+	),
+}
+
+/// Handle that is (temporarily) passed to `ChainSync` so it can
+/// communicate with `NetworkService` through `SyncingEngine`
+#[derive(Debug, Clone)]
+pub struct NetworkServiceHandle {
+	tx: TracingUnboundedSender<ToServiceCommand>,
+}
+
+impl NetworkServiceHandle {
+	/// Create new service handle
+	pub fn new(tx: TracingUnboundedSender<ToServiceCommand>) -> NetworkServiceHandle {
+		Self { tx }
+	}
+
+	/// Report peer
+	pub fn report_peer(&self, who: PeerId, cost_benefit: ReputationChange) {
+		let _ = self.tx.unbounded_send(ToServiceCommand::ReportPeer(who, cost_benefit));
+	}
+
+	/// Disconnect peer
+	pub fn disconnect_peer(&self, who: PeerId, protocol: ProtocolName) {
+		let _ = self.tx.unbounded_send(ToServiceCommand::DisconnectPeer(who, protocol));
+	}
+
+	/// Send request to peer
+	pub fn start_request(
+		&self,
+		who: PeerId,
+		protocol: ProtocolName,
+		request: Vec<u8>,
+		tx: oneshot::Sender<Result<(Vec<u8>, ProtocolName), RequestFailure>>,
+		connect: IfDisconnected,
+	) {
+		let _ = self
+			.tx
+			.unbounded_send(ToServiceCommand::StartRequest(who, protocol, request, tx, connect));
+	}
+}
+
+impl NetworkServiceProvider {
+	/// Create new `NetworkServiceProvider`
+	pub fn new() -> Self {
+		let (tx, rx) = tracing_unbounded("mpsc_network_service_provider", 100_000);
+
+		Self { rx, handle: NetworkServiceHandle::new(tx) }
+	}
+
+	/// Get handle to talk to the provider
+	pub fn handle(&self) -> NetworkServiceHandle {
+		self.handle.clone()
+	}
+
+	/// Run the `NetworkServiceProvider`
+	pub async fn run(self, service: Arc<dyn Network + Send + Sync>) {
+		let Self { mut rx, handle } = self;
+		drop(handle);
+
+		while let Some(inner) = rx.next().await {
+			match inner {
+				ToServiceCommand::DisconnectPeer(peer, protocol_name) =>
+					service.disconnect_peer(peer, protocol_name),
+				ToServiceCommand::ReportPeer(peer, reputation_change) =>
+					service.report_peer(peer, reputation_change),
+				ToServiceCommand::StartRequest(peer, protocol, request, tx, connect) =>
+					service.start_request(peer, protocol, request, None, tx, connect),
+			}
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::service::mock::MockNetwork;
+
+	// typical pattern in `Protocol` code where peer is disconnected
+	// and then reported
+	#[tokio::test]
+	async fn disconnect_and_report_peer() {
+		let provider = NetworkServiceProvider::new();
+		let handle = provider.handle();
+
+		let peer = PeerId::random();
+		let proto = ProtocolName::from("test-protocol");
+		let proto_clone = proto.clone();
+		let change = pezsc_network::ReputationChange::new_fatal("test-change");
+
+		let mut mock_network = MockNetwork::new();
+		mock_network
+			.expect_disconnect_peer()
+			.withf(move |in_peer, in_proto| &peer == in_peer && &proto == in_proto)
+			.once()
+			.returning(|_, _| ());
+		mock_network
+			.expect_report_peer()
+			.withf(move |in_peer, in_change| &peer == in_peer && &change == in_change)
+			.once()
+			.returning(|_, _| ());
+
+		tokio::spawn(async move {
+			provider.run(Arc::new(mock_network)).await;
+		});
+
+		handle.disconnect_peer(peer, proto_clone);
+		handle.report_peer(peer, change);
+	}
+}

bizinikiwi/client/network/sync/src/service/syncing_service.rs

@@ -0,0 +1,239 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::types::{ExtendedPeerInfo, SyncEvent, SyncEventStream, SyncStatus, SyncStatusProvider};
+
+use futures::{channel::oneshot, Stream};
+use pezsc_network_types::PeerId;
+
+use pezsc_consensus::{
+	BlockImportError, BlockImportStatus, JustificationImportResult, JustificationSyncLink, Link,
+};
+use pezsc_network::{NetworkBlock, NetworkSyncForkRequest};
+use pezsc_utils::mpsc::{tracing_unbounded, TracingUnboundedSender};
+use pezsp_runtime::traits::{Block as BlockT, NumberFor};
+
+use std::{
+	pin::Pin,
+	sync::{
+		atomic::{AtomicBool, AtomicUsize, Ordering},
+		Arc,
+	},
+};
+
+/// Commands send to `SyncingEngine`
+pub enum ToServiceCommand<B: BlockT> {
+	SetSyncForkRequest(Vec<PeerId>, B::Hash, NumberFor<B>),
+	RequestJustification(B::Hash, NumberFor<B>),
+	ClearJustificationRequests,
+	BlocksProcessed(
+		usize,
+		usize,
+		Vec<(Result<BlockImportStatus<NumberFor<B>>, BlockImportError>, B::Hash)>,
+	),
+	JustificationImported(PeerId, B::Hash, NumberFor<B>, JustificationImportResult),
+	AnnounceBlock(B::Hash, Option<Vec<u8>>),
+	NewBestBlockImported(B::Hash, NumberFor<B>),
+	EventStream(TracingUnboundedSender<SyncEvent>),
+	Status(oneshot::Sender<SyncStatus<B>>),
+	NumActivePeers(oneshot::Sender<usize>),
+	NumDownloadedBlocks(oneshot::Sender<usize>),
+	NumSyncRequests(oneshot::Sender<usize>),
+	PeersInfo(oneshot::Sender<Vec<(PeerId, ExtendedPeerInfo<B>)>>),
+	OnBlockFinalized(B::Hash, B::Header),
+	// Status {
+	// 	pending_response: oneshot::Sender<SyncStatus<B>>,
+	// },
+}
+
+/// Handle for communicating with `SyncingEngine` asynchronously
+#[derive(Clone)]
+pub struct SyncingService<B: BlockT> {
+	tx: TracingUnboundedSender<ToServiceCommand<B>>,
+	/// Number of peers we're connected to.
+	num_connected: Arc<AtomicUsize>,
+	/// Are we actively catching up with the chain?
+	is_major_syncing: Arc<AtomicBool>,
+}
+
+impl<B: BlockT> SyncingService<B> {
+	/// Create new handle
+	pub fn new(
+		tx: TracingUnboundedSender<ToServiceCommand<B>>,
+		num_connected: Arc<AtomicUsize>,
+		is_major_syncing: Arc<AtomicBool>,
+	) -> Self {
+		Self { tx, num_connected, is_major_syncing }
+	}
+
+	/// Get the number of peers known to `SyncingEngine` (both full and light).
+	pub fn num_connected_peers(&self) -> usize {
+		self.num_connected.load(Ordering::Relaxed)
+	}
+
+	/// Get the number of active peers.
+	pub async fn num_active_peers(&self) -> Result<usize, oneshot::Canceled> {
+		let (tx, rx) = oneshot::channel();
+		let _ = self.tx.unbounded_send(ToServiceCommand::NumActivePeers(tx));
+
+		rx.await
+	}
+
+	/// Get the number of downloaded blocks.
+	pub async fn num_downloaded_blocks(&self) -> Result<usize, oneshot::Canceled> {
+		let (tx, rx) = oneshot::channel();
+		let _ = self.tx.unbounded_send(ToServiceCommand::NumDownloadedBlocks(tx));
+
+		rx.await
+	}
+
+	/// Get the number of sync requests.
+	pub async fn num_sync_requests(&self) -> Result<usize, oneshot::Canceled> {
+		let (tx, rx) = oneshot::channel();
+		let _ = self.tx.unbounded_send(ToServiceCommand::NumSyncRequests(tx));
+
+		rx.await
+	}
+
+	/// Get peer information.
+	pub async fn peers_info(
+		&self,
+	) -> Result<Vec<(PeerId, ExtendedPeerInfo<B>)>, oneshot::Canceled> {
+		let (tx, rx) = oneshot::channel();
+		let _ = self.tx.unbounded_send(ToServiceCommand::PeersInfo(tx));
+
+		rx.await
+	}
+
+	/// Notify the `SyncingEngine` that a block has been finalized.
+	pub fn on_block_finalized(&self, hash: B::Hash, header: B::Header) {
+		let _ = self.tx.unbounded_send(ToServiceCommand::OnBlockFinalized(hash, header));
+	}
+
+	/// Get sync status
+	///
+	/// Returns an error if `SyncingEngine` has terminated.
+	pub async fn status(&self) -> Result<SyncStatus<B>, oneshot::Canceled> {
+		let (tx, rx) = oneshot::channel();
+		let _ = self.tx.unbounded_send(ToServiceCommand::Status(tx));
+
+		rx.await
+	}
+}
+
+impl<B: BlockT + 'static> NetworkSyncForkRequest<B::Hash, NumberFor<B>> for SyncingService<B> {
+	/// Configure an explicit fork sync request.
+	///
+	/// Note that this function should not be used for recent blocks.
+	/// Sync should be able to download all the recent forks normally.
+	/// `set_sync_fork_request` should only be used if external code detects that there's
+	/// a stale fork missing.
+	///
+	/// Passing empty `peers` set effectively removes the sync request.
+	fn set_sync_fork_request(&self, peers: Vec<PeerId>, hash: B::Hash, number: NumberFor<B>) {
+		let _ = self
+			.tx
+			.unbounded_send(ToServiceCommand::SetSyncForkRequest(peers, hash, number));
+	}
+}
+
+impl<B: BlockT> JustificationSyncLink<B> for SyncingService<B> {
+	/// Request a justification for the given block from the network.
+	///
+	/// On success, the justification will be passed to the import queue that was part at
+	/// initialization as part of the configuration.
+	fn request_justification(&self, hash: &B::Hash, number: NumberFor<B>) {
+		let _ = self.tx.unbounded_send(ToServiceCommand::RequestJustification(*hash, number));
+	}
+
+	fn clear_justification_requests(&self) {
+		let _ = self.tx.unbounded_send(ToServiceCommand::ClearJustificationRequests);
+	}
+}
+
+#[async_trait::async_trait]
+impl<B: BlockT> SyncStatusProvider<B> for SyncingService<B> {
+	/// Get high-level view of the syncing status.
+	async fn status(&self) -> Result<SyncStatus<B>, ()> {
+		let (rtx, rrx) = oneshot::channel();
+
+		let _ = self.tx.unbounded_send(ToServiceCommand::Status(rtx));
+		rrx.await.map_err(|_| ())
+	}
+}
+
+impl<B: BlockT> Link<B> for SyncingService<B> {
+	fn blocks_processed(
+		&self,
+		imported: usize,
+		count: usize,
+		results: Vec<(Result<BlockImportStatus<NumberFor<B>>, BlockImportError>, B::Hash)>,
+	) {
+		let _ = self
+			.tx
+			.unbounded_send(ToServiceCommand::BlocksProcessed(imported, count, results));
+	}
+
+	fn justification_imported(
+		&self,
+		who: PeerId,
+		hash: &B::Hash,
+		number: NumberFor<B>,
+		import_result: JustificationImportResult,
+	) {
+		let _ = self.tx.unbounded_send(ToServiceCommand::JustificationImported(
+			who,
+			*hash,
+			number,
+			import_result,
+		));
+	}
+
+	fn request_justification(&self, hash: &B::Hash, number: NumberFor<B>) {
+		let _ = self.tx.unbounded_send(ToServiceCommand::RequestJustification(*hash, number));
+	}
+}
+
+impl<B: BlockT> SyncEventStream for SyncingService<B> {
+	/// Get syncing event stream.
+	fn event_stream(&self, name: &'static str) -> Pin<Box<dyn Stream<Item = SyncEvent> + Send>> {
+		let (tx, rx) = tracing_unbounded(name, 100_000);
+		let _ = self.tx.unbounded_send(ToServiceCommand::EventStream(tx));
+		Box::pin(rx)
+	}
+}
+
+impl<B: BlockT> NetworkBlock<B::Hash, NumberFor<B>> for SyncingService<B> {
+	fn announce_block(&self, hash: B::Hash, data: Option<Vec<u8>>) {
+		let _ = self.tx.unbounded_send(ToServiceCommand::AnnounceBlock(hash, data));
+	}
+
+	fn new_best_block_imported(&self, hash: B::Hash, number: NumberFor<B>) {
+		let _ = self.tx.unbounded_send(ToServiceCommand::NewBestBlockImported(hash, number));
+	}
+}
+
+impl<B: BlockT> pezsp_consensus::SyncOracle for SyncingService<B> {
+	fn is_major_syncing(&self) -> bool {
+		self.is_major_syncing.load(Ordering::Relaxed)
+	}
+
+	fn is_offline(&self) -> bool {
+		self.num_connected.load(Ordering::Relaxed) == 0
+	}
+}

bizinikiwi/client/network/sync/src/state_request_handler.rs

@@ -0,0 +1,295 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Bizinikiwi.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// Bizinikiwi is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Bizinikiwi is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Bizinikiwi. If not, see <https://www.gnu.org/licenses/>.
+
+//! Helper for handling (i.e. answering) state requests from a remote peer via the
+//! `crate::request_responses::RequestResponsesBehaviour`.
+
+use crate::{
+	schema::v1::{KeyValueStateEntry, StateEntry, StateRequest, StateResponse},
+	LOG_TARGET,
+};
+
+use codec::{Decode, Encode};
+use futures::{channel::oneshot, stream::StreamExt};
+use log::{debug, trace};
+use prost::Message;
+use pezsc_network_types::PeerId;
+use schnellru::{ByLength, LruMap};
+
+use pezsc_client_api::{BlockBackend, ProofProvider};
+use pezsc_network::{
+	config::ProtocolId,
+	request_responses::{IncomingRequest, OutgoingResponse},
+	NetworkBackend, MAX_RESPONSE_SIZE,
+};
+use pezsp_runtime::traits::Block as BlockT;
+
+use std::{
+	hash::{Hash, Hasher},
+	sync::Arc,
+	time::Duration,
+};
+
+const MAX_RESPONSE_BYTES: usize = 2 * 1024 * 1024; // Actual reponse may be bigger.
+const MAX_NUMBER_OF_SAME_REQUESTS_PER_PEER: usize = 2;
+
+mod rep {
+	use pezsc_network::ReputationChange as Rep;
+
+	/// Reputation change when a peer sent us the same request multiple times.
+	pub const SAME_REQUEST: Rep = Rep::new(i32::MIN, "Same state request multiple times");
+}
+
+/// Generates a `RequestResponseProtocolConfig` for the state request protocol, refusing incoming
+/// requests.
+pub fn generate_protocol_config<
+	Hash: AsRef<[u8]>,
+	B: BlockT,
+	N: NetworkBackend<B, <B as BlockT>::Hash>,
+>(
+	protocol_id: &ProtocolId,
+	genesis_hash: Hash,
+	fork_id: Option<&str>,
+	inbound_queue: async_channel::Sender<IncomingRequest>,
+) -> N::RequestResponseProtocolConfig {
+	N::request_response_config(
+		generate_protocol_name(genesis_hash, fork_id).into(),
+		std::iter::once(generate_legacy_protocol_name(protocol_id).into()).collect(),
+		1024 * 1024,
+		MAX_RESPONSE_SIZE,
+		Duration::from_secs(40),
+		Some(inbound_queue),
+	)
+}
+
+/// Generate the state protocol name from the genesis hash and fork id.
+fn generate_protocol_name<Hash: AsRef<[u8]>>(genesis_hash: Hash, fork_id: Option<&str>) -> String {
+	let genesis_hash = genesis_hash.as_ref();
+	if let Some(fork_id) = fork_id {
+		format!("/{}/{}/state/2", array_bytes::bytes2hex("", genesis_hash), fork_id)
+	} else {
+		format!("/{}/state/2", array_bytes::bytes2hex("", genesis_hash))
+	}
+}
+
+/// Generate the legacy state protocol name from chain specific protocol identifier.
+fn generate_legacy_protocol_name(protocol_id: &ProtocolId) -> String {
+	format!("/{}/state/2", protocol_id.as_ref())
+}
+
+/// The key of [`BlockRequestHandler::seen_requests`].
+#[derive(Eq, PartialEq, Clone)]
+struct SeenRequestsKey<B: BlockT> {
+	peer: PeerId,
+	block: B::Hash,
+	start: Vec<Vec<u8>>,
+}
+
+#[allow(clippy::derived_hash_with_manual_eq)]
+impl<B: BlockT> Hash for SeenRequestsKey<B> {
+	fn hash<H: Hasher>(&self, state: &mut H) {
+		self.peer.hash(state);
+		self.block.hash(state);
+		self.start.hash(state);
+	}
+}
+
+/// The value of [`StateRequestHandler::seen_requests`].
+enum SeenRequestsValue {
+	/// First time we have seen the request.
+	First,
+	/// We have fulfilled the request `n` times.
+	Fulfilled(usize),
+}
+
+/// Handler for incoming block requests from a remote peer.
+pub struct StateRequestHandler<B: BlockT, Client> {
+	client: Arc<Client>,
+	request_receiver: async_channel::Receiver<IncomingRequest>,
+	/// Maps from request to number of times we have seen this request.
+	///
+	/// This is used to check if a peer is spamming us with the same request.
+	seen_requests: LruMap<SeenRequestsKey<B>, SeenRequestsValue>,
+}
+
+impl<B, Client> StateRequestHandler<B, Client>
+where
+	B: BlockT,
+	Client: BlockBackend<B> + ProofProvider<B> + Send + Sync + 'static,
+{
+	/// Create a new [`StateRequestHandler`].
+	pub fn new<N: NetworkBackend<B, <B as BlockT>::Hash>>(
+		protocol_id: &ProtocolId,
+		fork_id: Option<&str>,
+		client: Arc<Client>,
+		num_peer_hint: usize,
+	) -> (Self, N::RequestResponseProtocolConfig) {
+		// Reserve enough request slots for one request per peer when we are at the maximum
+		// number of peers.
+		let capacity = std::cmp::max(num_peer_hint, 1);
+		let (tx, request_receiver) = async_channel::bounded(capacity);
+
+		let protocol_config = generate_protocol_config::<_, B, N>(
+			protocol_id,
+			client
+				.block_hash(0u32.into())
+				.ok()
+				.flatten()
+				.expect("Genesis block exists; qed"),
+			fork_id,
+			tx,
+		);
+
+		let capacity = ByLength::new(num_peer_hint.max(1) as u32 * 2);
+		let seen_requests = LruMap::new(capacity);
+
+		(Self { client, request_receiver, seen_requests }, protocol_config)
+	}
+
+	/// Run [`StateRequestHandler`].
+	pub async fn run(mut self) {
+		while let Some(request) = self.request_receiver.next().await {
+			let IncomingRequest { peer, payload, pending_response } = request;
+
+			match self.handle_request(payload, pending_response, &peer) {
+				Ok(()) => debug!(target: LOG_TARGET, "Handled block request from {}.", peer),
+				Err(e) => debug!(
+					target: LOG_TARGET,
+					"Failed to handle state request from {}: {}", peer, e,
+				),
+			}
+		}
+	}
+
+	fn handle_request(
+		&mut self,
+		payload: Vec<u8>,
+		pending_response: oneshot::Sender<OutgoingResponse>,
+		peer: &PeerId,
+	) -> Result<(), HandleRequestError> {
+		let request = StateRequest::decode(&payload[..])?;
+		let block: B::Hash = Decode::decode(&mut request.block.as_ref())?;
+
+		let key = SeenRequestsKey { peer: *peer, block, start: request.start.clone() };
+
+		let mut reputation_changes = Vec::new();
+
+		match self.seen_requests.get(&key) {
+			Some(SeenRequestsValue::First) => {},
+			Some(SeenRequestsValue::Fulfilled(ref mut requests)) => {
+				*requests = requests.saturating_add(1);
+
+				if *requests > MAX_NUMBER_OF_SAME_REQUESTS_PER_PEER {
+					reputation_changes.push(rep::SAME_REQUEST);
+				}
+			},
+			None => {
+				self.seen_requests.insert(key.clone(), SeenRequestsValue::First);
+			},
+		}
+
+		trace!(
+			target: LOG_TARGET,
+			"Handling state request from {}: Block {:?}, Starting at {:x?}, no_proof={}",
+			peer,
+			request.block,
+			&request.start,
+			request.no_proof,
+		);
+
+		let result = if reputation_changes.is_empty() {
+			let mut response = StateResponse::default();
+
+			if !request.no_proof {
+				let (proof, _count) = self.client.read_proof_collection(
+					block,
+					request.start.as_slice(),
+					MAX_RESPONSE_BYTES,
+				)?;
+				response.proof = proof.encode();
+			} else {
+				let entries = self.client.storage_collection(
+					block,
+					request.start.as_slice(),
+					MAX_RESPONSE_BYTES,
+				)?;
+				response.entries = entries
+					.into_iter()
+					.map(|(state, complete)| KeyValueStateEntry {
+						state_root: state.state_root,
+						entries: state
+							.key_values
+							.into_iter()
+							.map(|(key, value)| StateEntry { key, value })
+							.collect(),
+						complete,
+					})
+					.collect();
+			}
+
+			trace!(
+				target: LOG_TARGET,
+				"StateResponse contains {} keys, {}, proof nodes, from {:?} to {:?}",
+				response.entries.len(),
+				response.proof.len(),
+				response.entries.get(0).and_then(|top| top
+					.entries
+					.first()
+					.map(|e| pezsp_core::hexdisplay::HexDisplay::from(&e.key))),
+				response.entries.get(0).and_then(|top| top
+					.entries
+					.last()
+					.map(|e| pezsp_core::hexdisplay::HexDisplay::from(&e.key))),
+			);
+			if let Some(value) = self.seen_requests.get(&key) {
+				// If this is the first time we have processed this request, we need to change
+				// it to `Fulfilled`.
+				if let SeenRequestsValue::First = value {
+					*value = SeenRequestsValue::Fulfilled(1);
+				}
+			}
+
+			let mut data = Vec::with_capacity(response.encoded_len());
+			response.encode(&mut data)?;
+			Ok(data)
+		} else {
+			Err(())
+		};
+
+		pending_response
+			.send(OutgoingResponse { result, reputation_changes, sent_feedback: None })
+			.map_err(|_| HandleRequestError::SendResponse)
+	}
+}
+
+#[derive(Debug, thiserror::Error)]
+enum HandleRequestError {
+	#[error("Failed to decode request: {0}.")]
+	DecodeProto(#[from] prost::DecodeError),
+
+	#[error("Failed to encode response: {0}.")]
+	EncodeProto(#[from] prost::EncodeError),
+
+	#[error("Failed to decode block hash: {0}.")]
+	InvalidHash(#[from] codec::Error),
+
+	#[error(transparent)]
+	Client(#[from] pezsp_blockchain::Error),
+
+	#[error("Failed to send response.")]
+	SendResponse,
+}

bizinikiwi/client/network/sync/src/strategy.rs

@@ -0,0 +1,224 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! [`SyncingStrategy`] defines an interface [`crate::engine::SyncingEngine`] uses as a specific
+//! syncing algorithm.
+//!
+//! A few different strategies are provided by Bizinikiwi out of the box with custom strategies
+//! possible too.
+
+pub mod chain_sync;
+mod disconnected_peers;
+pub mod pezkuwi;
+pub mod state;
+pub mod state_sync;
+pub mod warp;
+
+use crate::{
+	pending_responses::ResponseFuture,
+	service::network::NetworkServiceHandle,
+	types::{BadPeer, SyncStatus},
+};
+use pezsc_consensus::{BlockImportError, BlockImportStatus, IncomingBlock};
+use pezsc_network::ProtocolName;
+use pezsc_network_common::sync::message::BlockAnnounce;
+use pezsc_network_types::PeerId;
+use pezsp_blockchain::Error as ClientError;
+use pezsp_consensus::BlockOrigin;
+use pezsp_runtime::{
+	traits::{Block as BlockT, NumberFor},
+	Justifications,
+};
+use std::any::Any;
+
+/// Syncing strategy for syncing engine to use
+pub trait SyncingStrategy<B: BlockT>: Send
+where
+	B: BlockT,
+{
+	/// Notify syncing state machine that a new sync peer has connected.
+	fn add_peer(&mut self, peer_id: PeerId, best_hash: B::Hash, best_number: NumberFor<B>);
+
+	/// Notify that a sync peer has disconnected.
+	fn remove_peer(&mut self, peer_id: &PeerId);
+
+	/// Submit a validated block announcement.
+	///
+	/// Returns new best hash & best number of the peer if they are updated.
+	#[must_use]
+	fn on_validated_block_announce(
+		&mut self,
+		is_best: bool,
+		peer_id: PeerId,
+		announce: &BlockAnnounce<B::Header>,
+	) -> Option<(B::Hash, NumberFor<B>)>;
+
+	/// Configure an explicit fork sync request in case external code has detected that there is a
+	/// stale fork missing.
+	///
+	/// Note that this function should not be used for recent blocks.
+	/// Sync should be able to download all the recent forks normally.
+	///
+	/// Passing empty `peers` set effectively removes the sync request.
+	fn set_sync_fork_request(&mut self, peers: Vec<PeerId>, hash: &B::Hash, number: NumberFor<B>);
+
+	/// Request extra justification.
+	fn request_justification(&mut self, hash: &B::Hash, number: NumberFor<B>);
+
+	/// Clear extra justification requests.
+	fn clear_justification_requests(&mut self);
+
+	/// Report a justification import (successful or not).
+	fn on_justification_import(&mut self, hash: B::Hash, number: NumberFor<B>, success: bool);
+
+	/// Process generic response.
+	///
+	/// Strategy has to create opaque response and should be to downcast it back into concrete type
+	/// internally. Failure to downcast is an implementation bug.
+	fn on_generic_response(
+		&mut self,
+		peer_id: &PeerId,
+		key: StrategyKey,
+		protocol_name: ProtocolName,
+		response: Box<dyn Any + Send>,
+	);
+
+	/// A batch of blocks that have been processed, with or without errors.
+	///
+	/// Call this when a batch of blocks that have been processed by the import queue, with or
+	/// without errors.
+	fn on_blocks_processed(
+		&mut self,
+		imported: usize,
+		count: usize,
+		results: Vec<(Result<BlockImportStatus<NumberFor<B>>, BlockImportError>, B::Hash)>,
+	);
+
+	/// Notify a syncing strategy that a block has been finalized.
+	fn on_block_finalized(&mut self, hash: &B::Hash, number: NumberFor<B>);
+
+	/// Inform sync about a new best imported block.
+	fn update_chain_info(&mut self, best_hash: &B::Hash, best_number: NumberFor<B>);
+
+	// Are we in major sync mode?
+	fn is_major_syncing(&self) -> bool;
+
+	/// Get the number of peers known to the syncing strategy.
+	fn num_peers(&self) -> usize;
+
+	/// Returns the current sync status.
+	fn status(&self) -> SyncStatus<B>;
+
+	/// Get the total number of downloaded blocks.
+	fn num_downloaded_blocks(&self) -> usize;
+
+	/// Get an estimate of the number of parallel sync requests.
+	fn num_sync_requests(&self) -> usize;
+
+	/// Get actions that should be performed by the owner on the strategy's behalf
+	#[must_use]
+	fn actions(
+		&mut self,
+		// TODO: Consider making this internal property of the strategy
+		network_service: &NetworkServiceHandle,
+	) -> Result<Vec<SyncingAction<B>>, ClientError>;
+}
+
+/// The key identifying a specific strategy for responses routing.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct StrategyKey(&'static str);
+
+impl StrategyKey {
+	/// Instantiate opaque strategy key.
+	pub const fn new(key: &'static str) -> Self {
+		Self(key)
+	}
+}
+
+pub enum SyncingAction<B: BlockT> {
+	/// Start request to peer.
+	StartRequest {
+		peer_id: PeerId,
+		key: StrategyKey,
+		request: ResponseFuture,
+		// Whether to remove obsolete pending responses.
+		remove_obsolete: bool,
+	},
+	/// Drop stale request.
+	CancelRequest { peer_id: PeerId, key: StrategyKey },
+	/// Peer misbehaved. Disconnect, report it and cancel any requests to it.
+	DropPeer(BadPeer),
+	/// Import blocks.
+	ImportBlocks { origin: BlockOrigin, blocks: Vec<IncomingBlock<B>> },
+	/// Import justifications.
+	ImportJustifications {
+		peer_id: PeerId,
+		hash: B::Hash,
+		number: NumberFor<B>,
+		justifications: Justifications,
+	},
+	/// Strategy finished. Nothing to do, this is handled by `PezkuwiSyncingStrategy`.
+	Finished,
+}
+
+// Note: Ideally we can deduce this information with #[derive(derive_more::Debug)].
+// However, we'd need a bump to the latest version 2 of the crate.
+impl<B> std::fmt::Debug for SyncingAction<B>
+where
+	B: BlockT,
+{
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		match &self {
+			Self::StartRequest { peer_id, key, remove_obsolete, .. } => {
+				write!(
+					f,
+					"StartRequest {{ peer_id: {:?}, key: {:?}, remove_obsolete: {:?} }}",
+					peer_id, key, remove_obsolete
+				)
+			},
+			Self::CancelRequest { peer_id, key } => {
+				write!(f, "CancelRequest {{ peer_id: {:?}, key: {:?} }}", peer_id, key)
+			},
+			Self::DropPeer(peer) => write!(f, "DropPeer({:?})", peer),
+			Self::ImportBlocks { blocks, .. } => write!(f, "ImportBlocks({:?})", blocks),
+			Self::ImportJustifications { hash, number, .. } => {
+				write!(f, "ImportJustifications({:?}, {:?})", hash, number)
+			},
+			Self::Finished => write!(f, "Finished"),
+		}
+	}
+}
+
+impl<B: BlockT> SyncingAction<B> {
+	/// Returns `true` if the syncing action has completed.
+	pub fn is_finished(&self) -> bool {
+		matches!(self, SyncingAction::Finished)
+	}
+
+	#[cfg(test)]
+	pub(crate) fn name(&self) -> &'static str {
+		match self {
+			Self::StartRequest { .. } => "StartRequest",
+			Self::CancelRequest { .. } => "CancelRequest",
+			Self::DropPeer(_) => "DropPeer",
+			Self::ImportBlocks { .. } => "ImportBlocks",
+			Self::ImportJustifications { .. } => "ImportJustifications",
+			Self::Finished => "Finished",
+		}
+	}
+}

bizinikiwi/client/network/sync/src/strategy/disconnected_peers.rs

@@ -0,0 +1,196 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::types::BadPeer;
+use pezsc_network::ReputationChange as Rep;
+use pezsc_network_types::PeerId;
+use schnellru::{ByLength, LruMap};
+
+const LOG_TARGET: &str = "sync::disconnected_peers";
+
+/// The maximum number of disconnected peers to keep track of.
+///
+/// When a peer disconnects, we must keep track if it was in the middle of a request.
+/// The peer may disconnect because it cannot keep up with the number of requests
+/// (ie not having enough resources available to handle the requests); or because it is malicious.
+const MAX_DISCONNECTED_PEERS_STATE: u32 = 512;
+
+/// The time we are going to backoff a peer that has disconnected with an inflight request.
+///
+/// The backoff time is calculated as `num_disconnects * DISCONNECTED_PEER_BACKOFF_SECONDS`.
+/// This is to prevent submitting a request to a peer that has disconnected because it could not
+/// keep up with the number of requests.
+///
+/// The peer may disconnect due to the keep-alive timeout, however disconnections without
+/// an inflight request are not tracked.
+const DISCONNECTED_PEER_BACKOFF_SECONDS: u64 = 60;
+
+/// Maximum number of disconnects with a request in flight before a peer is banned.
+const MAX_NUM_DISCONNECTS: u64 = 3;
+
+/// Peer disconnected with a request in flight after backoffs.
+///
+/// The peer may be slow to respond to the request after backoffs, or it refuses to respond.
+/// Report the peer and let the reputation system handle disconnecting the peer.
+pub const REPUTATION_REPORT: Rep = Rep::new_fatal("Peer disconnected with inflight after backoffs");
+
+/// The state of a disconnected peer with a request in flight.
+#[derive(Debug)]
+struct DisconnectedState {
+	/// The total number of disconnects.
+	num_disconnects: u64,
+	/// The time at the last disconnect.
+	last_disconnect: std::time::Instant,
+}
+
+impl DisconnectedState {
+	/// Create a new `DisconnectedState`.
+	pub fn new() -> Self {
+		Self { num_disconnects: 1, last_disconnect: std::time::Instant::now() }
+	}
+
+	/// Increment the number of disconnects.
+	pub fn increment(&mut self) {
+		self.num_disconnects = self.num_disconnects.saturating_add(1);
+		self.last_disconnect = std::time::Instant::now();
+	}
+
+	/// Get the number of disconnects.
+	pub fn num_disconnects(&self) -> u64 {
+		self.num_disconnects
+	}
+
+	/// Get the time of the last disconnect.
+	pub fn last_disconnect(&self) -> std::time::Instant {
+		self.last_disconnect
+	}
+}
+
+/// Tracks the state of disconnected peers with a request in flight.
+///
+/// This helps to prevent submitting requests to peers that have disconnected
+/// before responding to the request to offload the peer.
+pub struct DisconnectedPeers {
+	/// The state of disconnected peers.
+	disconnected_peers: LruMap<PeerId, DisconnectedState>,
+	/// Backoff duration in seconds.
+	backoff_seconds: u64,
+}
+
+impl DisconnectedPeers {
+	/// Create a new `DisconnectedPeers`.
+	pub fn new() -> Self {
+		Self {
+			disconnected_peers: LruMap::new(ByLength::new(MAX_DISCONNECTED_PEERS_STATE)),
+			backoff_seconds: DISCONNECTED_PEER_BACKOFF_SECONDS,
+		}
+	}
+
+	/// Insert a new peer to the persistent state if not seen before, or update the state if seen.
+	///
+	/// Returns true if the peer should be disconnected.
+	pub fn on_disconnect_during_request(&mut self, peer: PeerId) -> Option<BadPeer> {
+		if let Some(state) = self.disconnected_peers.get(&peer) {
+			state.increment();
+
+			let should_ban = state.num_disconnects() >= MAX_NUM_DISCONNECTS;
+			log::debug!(
+				target: LOG_TARGET,
+				"Disconnected known peer {peer} state: {state:?}, should ban: {should_ban}",
+			);
+
+			should_ban.then(|| {
+				// We can lose track of the peer state and let the banning mechanism handle
+				// the peer backoff.
+				//
+				// After the peer banning expires, if the peer continues to misbehave, it will be
+				// backed off again.
+				self.disconnected_peers.remove(&peer);
+				BadPeer(peer, REPUTATION_REPORT)
+			})
+		} else {
+			log::debug!(
+				target: LOG_TARGET,
+				"Added peer {peer} for the first time"
+			);
+			// First time we see this peer.
+			self.disconnected_peers.insert(peer, DisconnectedState::new());
+			None
+		}
+	}
+
+	/// Check if a peer is available for queries.
+	pub fn is_peer_available(&mut self, peer_id: &PeerId) -> bool {
+		let Some(state) = self.disconnected_peers.get(peer_id) else {
+			return true;
+		};
+
+		let elapsed = state.last_disconnect().elapsed();
+		if elapsed.as_secs() >= self.backoff_seconds * state.num_disconnects {
+			log::debug!(target: LOG_TARGET, "Peer {peer_id} is available for queries");
+			self.disconnected_peers.remove(peer_id);
+			true
+		} else {
+			log::debug!(target: LOG_TARGET,"Peer {peer_id} is backedoff");
+			false
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use std::time::Duration;
+
+	#[test]
+	fn test_disconnected_peer_state() {
+		let mut state = DisconnectedPeers::new();
+		let peer = PeerId::random();
+
+		// Is not part of the disconnected peers yet.
+		assert_eq!(state.is_peer_available(&peer), true);
+
+		for _ in 0..MAX_NUM_DISCONNECTS - 1 {
+			assert!(state.on_disconnect_during_request(peer).is_none());
+			assert_eq!(state.is_peer_available(&peer), false);
+		}
+
+		assert!(state.on_disconnect_during_request(peer).is_some());
+		// Peer is supposed to get banned and disconnected.
+		// The state ownership moves to the PeerStore.
+		assert!(state.disconnected_peers.get(&peer).is_none());
+	}
+
+	#[test]
+	fn ensure_backoff_time() {
+		const TEST_BACKOFF_SECONDS: u64 = 2;
+		let mut state = DisconnectedPeers {
+			disconnected_peers: LruMap::new(ByLength::new(1)),
+			backoff_seconds: TEST_BACKOFF_SECONDS,
+		};
+		let peer = PeerId::random();
+
+		assert!(state.on_disconnect_during_request(peer).is_none());
+		assert_eq!(state.is_peer_available(&peer), false);
+
+		// Wait until the backoff time has passed
+		std::thread::sleep(Duration::from_secs(TEST_BACKOFF_SECONDS + 1));
+
+		assert_eq!(state.is_peer_available(&peer), true);
+	}
+}

bizinikiwi/client/network/sync/src/strategy/pezkuwi.rs

@@ -0,0 +1,484 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! [`PezkuwiSyncingStrategy`] is a proxy between [`crate::engine::SyncingEngine`]
+//! and specific syncing algorithms.
+
+use crate::{
+	block_relay_protocol::BlockDownloader,
+	block_request_handler::MAX_BLOCKS_IN_RESPONSE,
+	service::network::NetworkServiceHandle,
+	strategy::{
+		chain_sync::{ChainSync, ChainSyncMode},
+		state::StateStrategy,
+		warp::{WarpSync, WarpSyncConfig},
+		StrategyKey, SyncingAction, SyncingStrategy,
+	},
+	types::SyncStatus,
+	LOG_TARGET,
+};
+use log::{debug, error, info, warn};
+use prometheus_endpoint::Registry;
+use pezsc_client_api::{BlockBackend, ProofProvider};
+use pezsc_consensus::{BlockImportError, BlockImportStatus};
+use pezsc_network::ProtocolName;
+use pezsc_network_common::sync::{message::BlockAnnounce, SyncMode};
+use pezsc_network_types::PeerId;
+use pezsp_blockchain::{Error as ClientError, HeaderBackend, HeaderMetadata};
+use pezsp_runtime::traits::{Block as BlockT, Header, NumberFor};
+use std::{any::Any, collections::HashMap, sync::Arc};
+
+/// Corresponding `ChainSync` mode.
+fn chain_sync_mode(sync_mode: SyncMode) -> ChainSyncMode {
+	match sync_mode {
+		SyncMode::Full => ChainSyncMode::Full,
+		SyncMode::LightState { skip_proofs, storage_chain_mode } =>
+			ChainSyncMode::LightState { skip_proofs, storage_chain_mode },
+		SyncMode::Warp => ChainSyncMode::Full,
+	}
+}
+
+/// Syncing configuration containing data for [`PezkuwiSyncingStrategy`].
+#[derive(Clone, Debug)]
+pub struct PezkuwiSyncingStrategyConfig<Block>
+where
+	Block: BlockT,
+{
+	/// Syncing mode.
+	pub mode: SyncMode,
+	/// The number of parallel downloads to guard against slow peers.
+	pub max_parallel_downloads: u32,
+	/// Maximum number of blocks to request.
+	pub max_blocks_per_request: u32,
+	/// Number of peers that need to be connected before warp sync is started.
+	pub min_peers_to_start_warp_sync: Option<usize>,
+	/// Prometheus metrics registry.
+	pub metrics_registry: Option<Registry>,
+	/// Protocol name used to send out state requests
+	pub state_request_protocol_name: ProtocolName,
+	/// Block downloader
+	pub block_downloader: Arc<dyn BlockDownloader<Block>>,
+}
+
+/// Proxy to specific syncing strategies used in Pezkuwi.
+pub struct PezkuwiSyncingStrategy<B: BlockT, Client> {
+	/// Initial syncing configuration.
+	config: PezkuwiSyncingStrategyConfig<B>,
+	/// Client used by syncing strategies.
+	client: Arc<Client>,
+	/// Warp strategy.
+	warp: Option<WarpSync<B, Client>>,
+	/// State strategy.
+	state: Option<StateStrategy<B>>,
+	/// `ChainSync` strategy.`
+	chain_sync: Option<ChainSync<B, Client>>,
+	/// Connected peers and their best blocks used to seed a new strategy when switching to it in
+	/// `PezkuwiSyncingStrategy::proceed_to_next`.
+	peer_best_blocks: HashMap<PeerId, (B::Hash, NumberFor<B>)>,
+}
+
+impl<B: BlockT, Client> SyncingStrategy<B> for PezkuwiSyncingStrategy<B, Client>
+where
+	B: BlockT,
+	Client: HeaderBackend<B>
+		+ BlockBackend<B>
+		+ HeaderMetadata<B, Error = pezsp_blockchain::Error>
+		+ ProofProvider<B>
+		+ Send
+		+ Sync
+		+ 'static,
+{
+	fn add_peer(&mut self, peer_id: PeerId, best_hash: B::Hash, best_number: NumberFor<B>) {
+		self.peer_best_blocks.insert(peer_id, (best_hash, best_number));
+
+		self.warp.as_mut().map(|s| s.add_peer(peer_id, best_hash, best_number));
+		self.state.as_mut().map(|s| s.add_peer(peer_id, best_hash, best_number));
+		self.chain_sync.as_mut().map(|s| s.add_peer(peer_id, best_hash, best_number));
+	}
+
+	fn remove_peer(&mut self, peer_id: &PeerId) {
+		self.warp.as_mut().map(|s| s.remove_peer(peer_id));
+		self.state.as_mut().map(|s| s.remove_peer(peer_id));
+		self.chain_sync.as_mut().map(|s| s.remove_peer(peer_id));
+
+		self.peer_best_blocks.remove(peer_id);
+	}
+
+	fn on_validated_block_announce(
+		&mut self,
+		is_best: bool,
+		peer_id: PeerId,
+		announce: &BlockAnnounce<B::Header>,
+	) -> Option<(B::Hash, NumberFor<B>)> {
+		let new_best = if let Some(ref mut warp) = self.warp {
+			warp.on_validated_block_announce(is_best, peer_id, announce)
+		} else if let Some(ref mut state) = self.state {
+			state.on_validated_block_announce(is_best, peer_id, announce)
+		} else if let Some(ref mut chain_sync) = self.chain_sync {
+			chain_sync.on_validated_block_announce(is_best, peer_id, announce)
+		} else {
+			error!(target: LOG_TARGET, "No syncing strategy is active.");
+			debug_assert!(false);
+			Some((announce.header.hash(), *announce.header.number()))
+		};
+
+		if let Some(new_best) = new_best {
+			if let Some(best) = self.peer_best_blocks.get_mut(&peer_id) {
+				*best = new_best;
+			} else {
+				debug!(
+					target: LOG_TARGET,
+					"Cannot update `peer_best_blocks` as peer {peer_id} is not known to `Strategy` \
+					 (already disconnected?)",
+				);
+			}
+		}
+
+		new_best
+	}
+
+	fn set_sync_fork_request(&mut self, peers: Vec<PeerId>, hash: &B::Hash, number: NumberFor<B>) {
+		// Fork requests are only handled by `ChainSync`.
+		if let Some(ref mut chain_sync) = self.chain_sync {
+			chain_sync.set_sync_fork_request(peers.clone(), hash, number);
+		}
+	}
+
+	fn request_justification(&mut self, hash: &B::Hash, number: NumberFor<B>) {
+		// Justifications can only be requested via `ChainSync`.
+		if let Some(ref mut chain_sync) = self.chain_sync {
+			chain_sync.request_justification(hash, number);
+		}
+	}
+
+	fn clear_justification_requests(&mut self) {
+		// Justification requests can only be cleared by `ChainSync`.
+		if let Some(ref mut chain_sync) = self.chain_sync {
+			chain_sync.clear_justification_requests();
+		}
+	}
+
+	fn on_justification_import(&mut self, hash: B::Hash, number: NumberFor<B>, success: bool) {
+		// Only `ChainSync` is interested in justification import.
+		if let Some(ref mut chain_sync) = self.chain_sync {
+			chain_sync.on_justification_import(hash, number, success);
+		}
+	}
+
+	fn on_generic_response(
+		&mut self,
+		peer_id: &PeerId,
+		key: StrategyKey,
+		protocol_name: ProtocolName,
+		response: Box<dyn Any + Send>,
+	) {
+		match key {
+			StateStrategy::<B>::STRATEGY_KEY =>
+				if let Some(state) = &mut self.state {
+					let Ok(response) = response.downcast::<Vec<u8>>() else {
+						warn!(target: LOG_TARGET, "Failed to downcast state response");
+						debug_assert!(false);
+						return;
+					};
+
+					state.on_state_response(peer_id, *response);
+				} else if let Some(chain_sync) = &mut self.chain_sync {
+					chain_sync.on_generic_response(peer_id, key, protocol_name, response);
+				} else {
+					error!(
+						target: LOG_TARGET,
+						"`on_generic_response()` called with unexpected key {key:?} \
+						 or corresponding strategy is not active.",
+					);
+					debug_assert!(false);
+				},
+			WarpSync::<B, Client>::STRATEGY_KEY =>
+				if let Some(warp) = &mut self.warp {
+					warp.on_generic_response(peer_id, protocol_name, response);
+				} else {
+					error!(
+						target: LOG_TARGET,
+						"`on_generic_response()` called with unexpected key {key:?} \
+						 or warp strategy is not active",
+					);
+					debug_assert!(false);
+				},
+			ChainSync::<B, Client>::STRATEGY_KEY =>
+				if let Some(chain_sync) = &mut self.chain_sync {
+					chain_sync.on_generic_response(peer_id, key, protocol_name, response);
+				} else {
+					error!(
+						target: LOG_TARGET,
+						"`on_generic_response()` called with unexpected key {key:?} \
+						 or corresponding strategy is not active.",
+					);
+					debug_assert!(false);
+				},
+			key => {
+				warn!(
+					target: LOG_TARGET,
+					"Unexpected generic response strategy key {key:?}, protocol {protocol_name}",
+				);
+				debug_assert!(false);
+			},
+		}
+	}
+
+	fn on_blocks_processed(
+		&mut self,
+		imported: usize,
+		count: usize,
+		results: Vec<(Result<BlockImportStatus<NumberFor<B>>, BlockImportError>, B::Hash)>,
+	) {
+		// Only `StateStrategy` and `ChainSync` are interested in block processing notifications.
+		if let Some(ref mut state) = self.state {
+			state.on_blocks_processed(imported, count, results);
+		} else if let Some(ref mut chain_sync) = self.chain_sync {
+			chain_sync.on_blocks_processed(imported, count, results);
+		}
+	}
+
+	fn on_block_finalized(&mut self, hash: &B::Hash, number: NumberFor<B>) {
+		// Only `ChainSync` is interested in block finalization notifications.
+		if let Some(ref mut chain_sync) = self.chain_sync {
+			chain_sync.on_block_finalized(hash, number);
+		}
+	}
+
+	fn update_chain_info(&mut self, best_hash: &B::Hash, best_number: NumberFor<B>) {
+		// This is relevant to `ChainSync` only.
+		if let Some(ref mut chain_sync) = self.chain_sync {
+			chain_sync.update_chain_info(best_hash, best_number);
+		}
+	}
+
+	fn is_major_syncing(&self) -> bool {
+		self.warp.is_some() ||
+			self.state.is_some() ||
+			match self.chain_sync {
+				Some(ref s) => s.status().state.is_major_syncing(),
+				None => unreachable!("At least one syncing strategy is active; qed"),
+			}
+	}
+
+	fn num_peers(&self) -> usize {
+		self.peer_best_blocks.len()
+	}
+
+	fn status(&self) -> SyncStatus<B> {
+		// This function presumes that strategies are executed serially and must be refactored
+		// once we have parallel strategies.
+		if let Some(ref warp) = self.warp {
+			warp.status()
+		} else if let Some(ref state) = self.state {
+			state.status()
+		} else if let Some(ref chain_sync) = self.chain_sync {
+			chain_sync.status()
+		} else {
+			unreachable!("At least one syncing strategy is always active; qed")
+		}
+	}
+
+	fn num_downloaded_blocks(&self) -> usize {
+		self.chain_sync
+			.as_ref()
+			.map_or(0, |chain_sync| chain_sync.num_downloaded_blocks())
+	}
+
+	fn num_sync_requests(&self) -> usize {
+		self.chain_sync.as_ref().map_or(0, |chain_sync| chain_sync.num_sync_requests())
+	}
+
+	fn actions(
+		&mut self,
+		network_service: &NetworkServiceHandle,
+	) -> Result<Vec<SyncingAction<B>>, ClientError> {
+		// This function presumes that strategies are executed serially and must be refactored once
+		// we have parallel strategies.
+		let actions: Vec<_> = if let Some(ref mut warp) = self.warp {
+			warp.actions(network_service).map(Into::into).collect()
+		} else if let Some(ref mut state) = self.state {
+			state.actions(network_service).map(Into::into).collect()
+		} else if let Some(ref mut chain_sync) = self.chain_sync {
+			chain_sync.actions(network_service)?
+		} else {
+			unreachable!("At least one syncing strategy is always active; qed")
+		};
+
+		if actions.iter().any(SyncingAction::is_finished) {
+			self.proceed_to_next()?;
+		}
+
+		Ok(actions)
+	}
+}
+
+impl<B: BlockT, Client> PezkuwiSyncingStrategy<B, Client>
+where
+	B: BlockT,
+	Client: HeaderBackend<B>
+		+ BlockBackend<B>
+		+ HeaderMetadata<B, Error = pezsp_blockchain::Error>
+		+ ProofProvider<B>
+		+ Send
+		+ Sync
+		+ 'static,
+{
+	/// Initialize a new syncing strategy.
+	pub fn new(
+		mut config: PezkuwiSyncingStrategyConfig<B>,
+		client: Arc<Client>,
+		warp_sync_config: Option<WarpSyncConfig<B>>,
+		warp_sync_protocol_name: Option<ProtocolName>,
+	) -> Result<Self, ClientError> {
+		if config.max_blocks_per_request > MAX_BLOCKS_IN_RESPONSE as u32 {
+			info!(
+				target: LOG_TARGET,
+				"clamping maximum blocks per request to {MAX_BLOCKS_IN_RESPONSE}",
+			);
+			config.max_blocks_per_request = MAX_BLOCKS_IN_RESPONSE as u32;
+		}
+
+		if let SyncMode::Warp = config.mode {
+			let warp_sync_config = warp_sync_config
+				.expect("Warp sync configuration must be supplied in warp sync mode.");
+			let warp_sync = WarpSync::new(
+				client.clone(),
+				warp_sync_config,
+				warp_sync_protocol_name,
+				config.block_downloader.clone(),
+				config.min_peers_to_start_warp_sync,
+			);
+			Ok(Self {
+				config,
+				client,
+				warp: Some(warp_sync),
+				state: None,
+				chain_sync: None,
+				peer_best_blocks: Default::default(),
+			})
+		} else {
+			let chain_sync = ChainSync::new(
+				chain_sync_mode(config.mode),
+				client.clone(),
+				config.max_parallel_downloads,
+				config.max_blocks_per_request,
+				config.state_request_protocol_name.clone(),
+				config.block_downloader.clone(),
+				config.metrics_registry.as_ref(),
+				std::iter::empty(),
+			)?;
+			Ok(Self {
+				config,
+				client,
+				warp: None,
+				state: None,
+				chain_sync: Some(chain_sync),
+				peer_best_blocks: Default::default(),
+			})
+		}
+	}
+
+	/// Proceed with the next strategy if the active one finished.
+	pub fn proceed_to_next(&mut self) -> Result<(), ClientError> {
+		// The strategies are switched as `WarpSync` -> `StateStrategy` -> `ChainSync`.
+		if let Some(ref mut warp) = self.warp {
+			match warp.take_result() {
+				Some(res) => {
+					info!(
+						target: LOG_TARGET,
+						"Warp sync is complete, continuing with state sync."
+					);
+					let state_sync = StateStrategy::new(
+						self.client.clone(),
+						res.target_header,
+						res.target_body,
+						res.target_justifications,
+						false,
+						self.peer_best_blocks
+							.iter()
+							.map(|(peer_id, (_, best_number))| (*peer_id, *best_number)),
+						self.config.state_request_protocol_name.clone(),
+					);
+
+					self.warp = None;
+					self.state = Some(state_sync);
+					Ok(())
+				},
+				None => {
+					error!(
+						target: LOG_TARGET,
+						"Warp sync failed. Continuing with full sync."
+					);
+					let chain_sync = match ChainSync::new(
+						chain_sync_mode(self.config.mode),
+						self.client.clone(),
+						self.config.max_parallel_downloads,
+						self.config.max_blocks_per_request,
+						self.config.state_request_protocol_name.clone(),
+						self.config.block_downloader.clone(),
+						self.config.metrics_registry.as_ref(),
+						self.peer_best_blocks.iter().map(|(peer_id, (best_hash, best_number))| {
+							(*peer_id, *best_hash, *best_number)
+						}),
+					) {
+						Ok(chain_sync) => chain_sync,
+						Err(e) => {
+							error!(target: LOG_TARGET, "Failed to start `ChainSync`.");
+							return Err(e);
+						},
+					};
+
+					self.warp = None;
+					self.chain_sync = Some(chain_sync);
+					Ok(())
+				},
+			}
+		} else if let Some(state) = &self.state {
+			if state.is_succeeded() {
+				info!(target: LOG_TARGET, "State sync is complete, continuing with block sync.");
+			} else {
+				error!(target: LOG_TARGET, "State sync failed. Falling back to full sync.");
+			}
+			let chain_sync = match ChainSync::new(
+				chain_sync_mode(self.config.mode),
+				self.client.clone(),
+				self.config.max_parallel_downloads,
+				self.config.max_blocks_per_request,
+				self.config.state_request_protocol_name.clone(),
+				self.config.block_downloader.clone(),
+				self.config.metrics_registry.as_ref(),
+				self.peer_best_blocks.iter().map(|(peer_id, (best_hash, best_number))| {
+					(*peer_id, *best_hash, *best_number)
+				}),
+			) {
+				Ok(chain_sync) => chain_sync,
+				Err(e) => {
+					error!(target: LOG_TARGET, "Failed to start `ChainSync`.");
+					return Err(e);
+				},
+			};
+
+			self.state = None;
+			self.chain_sync = Some(chain_sync);
+			Ok(())
+		} else {
+			unreachable!("Only warp & state strategies can finish; qed")
+		}
+	}
+}

bizinikiwi/client/network/sync/src/strategy/state.rs

@@ -0,0 +1,884 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! State sync strategy.
+
+use crate::{
+	schema::v1::{StateRequest, StateResponse},
+	service::network::NetworkServiceHandle,
+	strategy::{
+		disconnected_peers::DisconnectedPeers,
+		state_sync::{ImportResult, StateSync, StateSyncProvider},
+		StrategyKey, SyncingAction,
+	},
+	types::{BadPeer, SyncState, SyncStatus},
+	LOG_TARGET,
+};
+use futures::{channel::oneshot, FutureExt};
+use log::{debug, error, trace};
+use prost::Message;
+use pezsc_client_api::ProofProvider;
+use pezsc_consensus::{BlockImportError, BlockImportStatus, IncomingBlock};
+use pezsc_network::{IfDisconnected, ProtocolName};
+use pezsc_network_common::sync::message::BlockAnnounce;
+use pezsc_network_types::PeerId;
+use pezsp_consensus::BlockOrigin;
+use pezsp_runtime::{
+	traits::{Block as BlockT, Header, NumberFor},
+	Justifications, SaturatedConversion,
+};
+use std::{any::Any, collections::HashMap, sync::Arc};
+
+mod rep {
+	use pezsc_network::ReputationChange as Rep;
+
+	/// Peer response data does not have requested bits.
+	pub const BAD_RESPONSE: Rep = Rep::new(-(1 << 12), "Incomplete response");
+
+	/// Reputation change for peers which send us a known bad state.
+	pub const BAD_STATE: Rep = Rep::new(-(1 << 29), "Bad state");
+}
+
+enum PeerState {
+	Available,
+	DownloadingState,
+}
+
+impl PeerState {
+	fn is_available(&self) -> bool {
+		matches!(self, PeerState::Available)
+	}
+}
+
+struct Peer<B: BlockT> {
+	best_number: NumberFor<B>,
+	state: PeerState,
+}
+
+/// Syncing strategy that downloads and imports a recent state directly.
+pub struct StateStrategy<B: BlockT> {
+	state_sync: Box<dyn StateSyncProvider<B>>,
+	peers: HashMap<PeerId, Peer<B>>,
+	disconnected_peers: DisconnectedPeers,
+	actions: Vec<SyncingAction<B>>,
+	protocol_name: ProtocolName,
+	succeeded: bool,
+}
+
+impl<B: BlockT> StateStrategy<B> {
+	/// Strategy key used by state sync.
+	pub const STRATEGY_KEY: StrategyKey = StrategyKey::new("State");
+
+	/// Create a new instance.
+	pub fn new<Client>(
+		client: Arc<Client>,
+		target_header: B::Header,
+		target_body: Option<Vec<B::Extrinsic>>,
+		target_justifications: Option<Justifications>,
+		skip_proof: bool,
+		initial_peers: impl Iterator<Item = (PeerId, NumberFor<B>)>,
+		protocol_name: ProtocolName,
+	) -> Self
+	where
+		Client: ProofProvider<B> + Send + Sync + 'static,
+	{
+		let peers = initial_peers
+			.map(|(peer_id, best_number)| {
+				(peer_id, Peer { best_number, state: PeerState::Available })
+			})
+			.collect();
+		Self {
+			state_sync: Box::new(StateSync::new(
+				client,
+				target_header,
+				target_body,
+				target_justifications,
+				skip_proof,
+			)),
+			peers,
+			disconnected_peers: DisconnectedPeers::new(),
+			actions: Vec::new(),
+			protocol_name,
+			succeeded: false,
+		}
+	}
+
+	/// Create a new instance with a custom state sync provider.
+	///
+	/// Note: In most cases, users should use [`StateStrategy::new`].
+	/// This method is intended for custom sync strategies and advanced use cases.
+	pub fn new_with_provider(
+		state_sync_provider: Box<dyn StateSyncProvider<B>>,
+		initial_peers: impl Iterator<Item = (PeerId, NumberFor<B>)>,
+		protocol_name: ProtocolName,
+	) -> Self {
+		Self {
+			state_sync: state_sync_provider,
+			peers: initial_peers
+				.map(|(peer_id, best_number)| {
+					(peer_id, Peer { best_number, state: PeerState::Available })
+				})
+				.collect(),
+			disconnected_peers: DisconnectedPeers::new(),
+			actions: Vec::new(),
+			protocol_name,
+			succeeded: false,
+		}
+	}
+
+	/// Notify that a new peer has connected.
+	pub fn add_peer(&mut self, peer_id: PeerId, _best_hash: B::Hash, best_number: NumberFor<B>) {
+		self.peers.insert(peer_id, Peer { best_number, state: PeerState::Available });
+	}
+
+	/// Notify that a peer has disconnected.
+	pub fn remove_peer(&mut self, peer_id: &PeerId) {
+		if let Some(state) = self.peers.remove(peer_id) {
+			if !state.state.is_available() {
+				if let Some(bad_peer) =
+					self.disconnected_peers.on_disconnect_during_request(*peer_id)
+				{
+					self.actions.push(SyncingAction::DropPeer(bad_peer));
+				}
+			}
+		}
+	}
+
+	/// Submit a validated block announcement.
+	///
+	/// Returns new best hash & best number of the peer if they are updated.
+	#[must_use]
+	pub fn on_validated_block_announce(
+		&mut self,
+		is_best: bool,
+		peer_id: PeerId,
+		announce: &BlockAnnounce<B::Header>,
+	) -> Option<(B::Hash, NumberFor<B>)> {
+		is_best.then(|| {
+			let best_number = *announce.header.number();
+			let best_hash = announce.header.hash();
+			if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+				peer.best_number = best_number;
+			}
+			// Let `SyncingEngine` know that we should update the peer info.
+			(best_hash, best_number)
+		})
+	}
+
+	/// Process state response.
+	pub fn on_state_response(&mut self, peer_id: &PeerId, response: Vec<u8>) {
+		if let Err(bad_peer) = self.on_state_response_inner(peer_id, &response) {
+			self.actions.push(SyncingAction::DropPeer(bad_peer));
+		}
+	}
+
+	fn on_state_response_inner(
+		&mut self,
+		peer_id: &PeerId,
+		response: &[u8],
+	) -> Result<(), BadPeer> {
+		if let Some(peer) = self.peers.get_mut(&peer_id) {
+			peer.state = PeerState::Available;
+		}
+
+		let response = match StateResponse::decode(response) {
+			Ok(response) => response,
+			Err(error) => {
+				debug!(
+					target: LOG_TARGET,
+					"Failed to decode state response from peer {peer_id:?}: {error:?}.",
+				);
+
+				return Err(BadPeer(*peer_id, rep::BAD_RESPONSE));
+			},
+		};
+
+		debug!(
+			target: LOG_TARGET,
+			"Importing state data from {} with {} keys, {} proof nodes.",
+			peer_id,
+			response.entries.len(),
+			response.proof.len(),
+		);
+
+		match self.state_sync.import(response) {
+			ImportResult::Import(hash, header, state, body, justifications) => {
+				let origin = BlockOrigin::NetworkInitialSync;
+				let block = IncomingBlock {
+					hash,
+					header: Some(header),
+					body,
+					indexed_body: None,
+					justifications,
+					origin: None,
+					allow_missing_state: true,
+					import_existing: true,
+					skip_execution: true,
+					state: Some(state),
+				};
+				debug!(target: LOG_TARGET, "State download is complete. Import is queued");
+				self.actions.push(SyncingAction::ImportBlocks { origin, blocks: vec![block] });
+				Ok(())
+			},
+			ImportResult::Continue => Ok(()),
+			ImportResult::BadResponse => {
+				debug!(target: LOG_TARGET, "Bad state data received from {peer_id}");
+				Err(BadPeer(*peer_id, rep::BAD_STATE))
+			},
+		}
+	}
+
+	/// A batch of blocks have been processed, with or without errors.
+	///
+	/// Normally this should be called when target block with state is imported.
+	pub fn on_blocks_processed(
+		&mut self,
+		imported: usize,
+		count: usize,
+		results: Vec<(Result<BlockImportStatus<NumberFor<B>>, BlockImportError>, B::Hash)>,
+	) {
+		trace!(target: LOG_TARGET, "State sync: imported {imported} of {count}.");
+
+		let results = results
+			.into_iter()
+			.filter_map(|(result, hash)| {
+				if hash == self.state_sync.target_hash() {
+					Some(result)
+				} else {
+					debug!(
+						target: LOG_TARGET,
+						"Unexpected block processed: {hash} with result {result:?}.",
+					);
+					None
+				}
+			})
+			.collect::<Vec<_>>();
+
+		if !results.is_empty() {
+			// We processed the target block
+			results.iter().filter_map(|result| result.as_ref().err()).for_each(|e| {
+				error!(
+					target: LOG_TARGET,
+					"Failed to import target block with state: {e:?}."
+				);
+			});
+			self.succeeded |= results.into_iter().any(|result| result.is_ok());
+			self.actions.push(SyncingAction::Finished);
+		}
+	}
+
+	/// Produce state request.
+	fn state_request(&mut self) -> Option<(PeerId, StateRequest)> {
+		if self.state_sync.is_complete() {
+			return None;
+		}
+
+		if self
+			.peers
+			.values()
+			.any(|peer| matches!(peer.state, PeerState::DownloadingState))
+		{
+			// Only one state request at a time is possible.
+			return None;
+		}
+
+		let peer_id =
+			self.schedule_next_peer(PeerState::DownloadingState, self.state_sync.target_number())?;
+		let request = self.state_sync.next_request();
+		trace!(
+			target: LOG_TARGET,
+			"New state request to {peer_id}: {request:?}.",
+		);
+		Some((peer_id, request))
+	}
+
+	fn schedule_next_peer(
+		&mut self,
+		new_state: PeerState,
+		min_best_number: NumberFor<B>,
+	) -> Option<PeerId> {
+		let mut targets: Vec<_> = self.peers.values().map(|p| p.best_number).collect();
+		if targets.is_empty() {
+			return None;
+		}
+		targets.sort();
+		let median = targets[targets.len() / 2];
+		let threshold = std::cmp::max(median, min_best_number);
+		// Find a random peer that is synced as much as peer majority and is above
+		// `min_best_number`.
+		for (peer_id, peer) in self.peers.iter_mut() {
+			if peer.state.is_available() &&
+				peer.best_number >= threshold &&
+				self.disconnected_peers.is_peer_available(peer_id)
+			{
+				peer.state = new_state;
+				return Some(*peer_id);
+			}
+		}
+		None
+	}
+
+	/// Returns the current sync status.
+	pub fn status(&self) -> SyncStatus<B> {
+		SyncStatus {
+			state: if self.state_sync.is_complete() {
+				SyncState::Idle
+			} else {
+				SyncState::Downloading { target: self.state_sync.target_number() }
+			},
+			best_seen_block: Some(self.state_sync.target_number()),
+			num_peers: self.peers.len().saturated_into(),
+			queued_blocks: 0,
+			state_sync: Some(self.state_sync.progress()),
+			warp_sync: None,
+		}
+	}
+
+	/// Get actions that should be performed.
+	#[must_use]
+	pub fn actions(
+		&mut self,
+		network_service: &NetworkServiceHandle,
+	) -> impl Iterator<Item = SyncingAction<B>> {
+		let state_request = self.state_request().into_iter().map(|(peer_id, request)| {
+			let (tx, rx) = oneshot::channel();
+
+			network_service.start_request(
+				peer_id,
+				self.protocol_name.clone(),
+				request.encode_to_vec(),
+				tx,
+				IfDisconnected::ImmediateError,
+			);
+
+			SyncingAction::StartRequest {
+				peer_id,
+				key: Self::STRATEGY_KEY,
+				request: async move {
+					Ok(rx.await?.and_then(|(response, protocol_name)| {
+						Ok((Box::new(response) as Box<dyn Any + Send>, protocol_name))
+					}))
+				}
+				.boxed(),
+				remove_obsolete: false,
+			}
+		});
+		self.actions.extend(state_request);
+
+		std::mem::take(&mut self.actions).into_iter()
+	}
+
+	/// Check if state sync has succeeded.
+	#[must_use]
+	pub fn is_succeeded(&self) -> bool {
+		self.succeeded
+	}
+}
+
+#[cfg(test)]
+mod test {
+	use super::*;
+	use crate::{
+		schema::v1::{StateRequest, StateResponse},
+		service::network::NetworkServiceProvider,
+		strategy::state_sync::{ImportResult, StateSyncProgress, StateSyncProvider},
+	};
+	use codec::Decode;
+	use pezsc_block_builder::BlockBuilderBuilder;
+	use pezsc_client_api::KeyValueStates;
+	use pezsc_consensus::{ImportedAux, ImportedState};
+	use pezsp_core::H256;
+	use pezsp_runtime::traits::Zero;
+	use bizinikiwi_test_runtime_client::{
+		runtime::{Block, Hash},
+		BlockBuilderExt, DefaultTestClientBuilderExt, TestClientBuilder, TestClientBuilderExt,
+	};
+
+	mockall::mock! {
+		pub StateSync<B: BlockT> {}
+
+		impl<B: BlockT> StateSyncProvider<B> for StateSync<B> {
+			fn import(&mut self, response: StateResponse) -> ImportResult<B>;
+			fn next_request(&self) -> StateRequest;
+			fn is_complete(&self) -> bool;
+			fn target_number(&self) -> NumberFor<B>;
+			fn target_hash(&self) -> B::Hash;
+			fn progress(&self) -> StateSyncProgress;
+		}
+	}
+
+	#[test]
+	fn no_peer_is_scheduled_if_no_peers_connected() {
+		let client = Arc::new(TestClientBuilder::new().set_no_genesis().build());
+		let target_block = BlockBuilderBuilder::new(&*client)
+			.on_parent_block(client.chain_info().best_hash)
+			.with_parent_block_number(client.chain_info().best_number)
+			.build()
+			.unwrap()
+			.build()
+			.unwrap()
+			.block;
+		let target_header = target_block.header().clone();
+
+		let mut state_strategy = StateStrategy::new(
+			client,
+			target_header,
+			None,
+			None,
+			false,
+			std::iter::empty(),
+			ProtocolName::Static(""),
+		);
+
+		assert!(state_strategy
+			.schedule_next_peer(PeerState::DownloadingState, Zero::zero())
+			.is_none());
+	}
+
+	#[test]
+	fn at_least_median_synced_peer_is_scheduled() {
+		let client = Arc::new(TestClientBuilder::new().set_no_genesis().build());
+		let target_block = BlockBuilderBuilder::new(&*client)
+			.on_parent_block(client.chain_info().best_hash)
+			.with_parent_block_number(client.chain_info().best_number)
+			.build()
+			.unwrap()
+			.build()
+			.unwrap()
+			.block;
+
+		for _ in 0..100 {
+			let peers = (1..=10)
+				.map(|best_number| (PeerId::random(), best_number))
+				.collect::<HashMap<_, _>>();
+			let initial_peers = peers.iter().map(|(p, n)| (*p, *n));
+
+			let mut state_strategy = StateStrategy::new(
+				client.clone(),
+				target_block.header().clone(),
+				None,
+				None,
+				false,
+				initial_peers,
+				ProtocolName::Static(""),
+			);
+
+			let peer_id =
+				state_strategy.schedule_next_peer(PeerState::DownloadingState, Zero::zero());
+			assert!(*peers.get(&peer_id.unwrap()).unwrap() >= 6);
+		}
+	}
+
+	#[test]
+	fn min_best_number_peer_is_scheduled() {
+		let client = Arc::new(TestClientBuilder::new().set_no_genesis().build());
+		let target_block = BlockBuilderBuilder::new(&*client)
+			.on_parent_block(client.chain_info().best_hash)
+			.with_parent_block_number(client.chain_info().best_number)
+			.build()
+			.unwrap()
+			.build()
+			.unwrap()
+			.block;
+
+		for _ in 0..10 {
+			let peers = (1..=10)
+				.map(|best_number| (PeerId::random(), best_number))
+				.collect::<HashMap<_, _>>();
+			let initial_peers = peers.iter().map(|(p, n)| (*p, *n));
+
+			let mut state_strategy = StateStrategy::new(
+				client.clone(),
+				target_block.header().clone(),
+				None,
+				None,
+				false,
+				initial_peers,
+				ProtocolName::Static(""),
+			);
+
+			let peer_id = state_strategy.schedule_next_peer(PeerState::DownloadingState, 10);
+			assert!(*peers.get(&peer_id.unwrap()).unwrap() == 10);
+		}
+	}
+
+	#[test]
+	fn backedoff_number_peer_is_not_scheduled() {
+		let client = Arc::new(TestClientBuilder::new().set_no_genesis().build());
+		let target_block = BlockBuilderBuilder::new(&*client)
+			.on_parent_block(client.chain_info().best_hash)
+			.with_parent_block_number(client.chain_info().best_number)
+			.build()
+			.unwrap()
+			.build()
+			.unwrap()
+			.block;
+
+		let peers = (1..=10)
+			.map(|best_number| (PeerId::random(), best_number))
+			.collect::<Vec<(_, _)>>();
+		let ninth_peer = peers[8].0;
+		let tenth_peer = peers[9].0;
+		let initial_peers = peers.iter().map(|(p, n)| (*p, *n));
+
+		let mut state_strategy = StateStrategy::new(
+			client.clone(),
+			target_block.header().clone(),
+			None,
+			None,
+			false,
+			initial_peers,
+			ProtocolName::Static(""),
+		);
+
+		// Disconnecting a peer without an inflight request has no effect on persistent states.
+		state_strategy.remove_peer(&tenth_peer);
+		assert!(state_strategy.disconnected_peers.is_peer_available(&tenth_peer));
+
+		// Disconnect the peer with an inflight request.
+		state_strategy.add_peer(tenth_peer, H256::random(), 10);
+		let peer_id: Option<PeerId> =
+			state_strategy.schedule_next_peer(PeerState::DownloadingState, 10);
+		assert_eq!(tenth_peer, peer_id.unwrap());
+		state_strategy.remove_peer(&tenth_peer);
+
+		// Peer is backed off.
+		assert!(!state_strategy.disconnected_peers.is_peer_available(&tenth_peer));
+
+		// No peer available for 10'th best block because of the backoff.
+		state_strategy.add_peer(tenth_peer, H256::random(), 10);
+		let peer_id: Option<PeerId> =
+			state_strategy.schedule_next_peer(PeerState::DownloadingState, 10);
+		assert!(peer_id.is_none());
+
+		// Other requests can still happen.
+		let peer_id: Option<PeerId> =
+			state_strategy.schedule_next_peer(PeerState::DownloadingState, 9);
+		assert_eq!(ninth_peer, peer_id.unwrap());
+	}
+
+	#[test]
+	fn state_request_contains_correct_hash() {
+		let client = Arc::new(TestClientBuilder::new().set_no_genesis().build());
+		let target_block = BlockBuilderBuilder::new(&*client)
+			.on_parent_block(client.chain_info().best_hash)
+			.with_parent_block_number(client.chain_info().best_number)
+			.build()
+			.unwrap()
+			.build()
+			.unwrap()
+			.block;
+
+		let initial_peers = (1..=10).map(|best_number| (PeerId::random(), best_number));
+
+		let mut state_strategy = StateStrategy::new(
+			client.clone(),
+			target_block.header().clone(),
+			None,
+			None,
+			false,
+			initial_peers,
+			ProtocolName::Static(""),
+		);
+
+		let (_peer_id, request) = state_strategy.state_request().unwrap();
+		let hash = Hash::decode(&mut &*request.block).unwrap();
+
+		assert_eq!(hash, target_block.header().hash());
+	}
+
+	#[test]
+	fn no_parallel_state_requests() {
+		let client = Arc::new(TestClientBuilder::new().set_no_genesis().build());
+		let target_block = BlockBuilderBuilder::new(&*client)
+			.on_parent_block(client.chain_info().best_hash)
+			.with_parent_block_number(client.chain_info().best_number)
+			.build()
+			.unwrap()
+			.build()
+			.unwrap()
+			.block;
+
+		let initial_peers = (1..=10).map(|best_number| (PeerId::random(), best_number));
+
+		let mut state_strategy = StateStrategy::new(
+			client.clone(),
+			target_block.header().clone(),
+			None,
+			None,
+			false,
+			initial_peers,
+			ProtocolName::Static(""),
+		);
+
+		// First request is sent.
+		assert!(state_strategy.state_request().is_some());
+
+		// No parallel request is sent.
+		assert!(state_strategy.state_request().is_none());
+	}
+
+	#[test]
+	fn received_state_response_makes_peer_available_again() {
+		let mut state_sync_provider = MockStateSync::<Block>::new();
+		state_sync_provider.expect_import().return_once(|_| ImportResult::Continue);
+		let peer_id = PeerId::random();
+		let initial_peers = std::iter::once((peer_id, 10));
+		let mut state_strategy = StateStrategy::new_with_provider(
+			Box::new(state_sync_provider),
+			initial_peers,
+			ProtocolName::Static(""),
+		);
+		// Manually set the peer's state.
+		state_strategy.peers.get_mut(&peer_id).unwrap().state = PeerState::DownloadingState;
+
+		let dummy_response = StateResponse::default().encode_to_vec();
+		state_strategy.on_state_response(&peer_id, dummy_response);
+
+		assert!(state_strategy.peers.get(&peer_id).unwrap().state.is_available());
+	}
+
+	#[test]
+	fn bad_state_response_drops_peer() {
+		let mut state_sync_provider = MockStateSync::<Block>::new();
+		// Provider says that state response is bad.
+		state_sync_provider.expect_import().return_once(|_| ImportResult::BadResponse);
+		let peer_id = PeerId::random();
+		let initial_peers = std::iter::once((peer_id, 10));
+		let mut state_strategy = StateStrategy::new_with_provider(
+			Box::new(state_sync_provider),
+			initial_peers,
+			ProtocolName::Static(""),
+		);
+		// Manually set the peer's state.
+		state_strategy.peers.get_mut(&peer_id).unwrap().state = PeerState::DownloadingState;
+		let dummy_response = StateResponse::default().encode_to_vec();
+		// Receiving response drops the peer.
+		assert!(matches!(
+			state_strategy.on_state_response_inner(&peer_id, &dummy_response),
+			Err(BadPeer(id, _rep)) if id == peer_id,
+		));
+	}
+
+	#[test]
+	fn partial_state_response_doesnt_generate_actions() {
+		let mut state_sync_provider = MockStateSync::<Block>::new();
+		// Sync provider says that the response is partial.
+		state_sync_provider.expect_import().return_once(|_| ImportResult::Continue);
+		let peer_id = PeerId::random();
+		let initial_peers = std::iter::once((peer_id, 10));
+		let mut state_strategy = StateStrategy::new_with_provider(
+			Box::new(state_sync_provider),
+			initial_peers,
+			ProtocolName::Static(""),
+		);
+		// Manually set the peer's state .
+		state_strategy.peers.get_mut(&peer_id).unwrap().state = PeerState::DownloadingState;
+
+		let dummy_response = StateResponse::default().encode_to_vec();
+		state_strategy.on_state_response(&peer_id, dummy_response);
+
+		// No actions generated.
+		assert_eq!(state_strategy.actions.len(), 0)
+	}
+
+	#[test]
+	fn complete_state_response_leads_to_block_import() {
+		// Build block to use for checks.
+		let client = Arc::new(TestClientBuilder::new().set_no_genesis().build());
+		let mut block_builder = BlockBuilderBuilder::new(&*client)
+			.on_parent_block(client.chain_info().best_hash)
+			.with_parent_block_number(client.chain_info().best_number)
+			.build()
+			.unwrap();
+		block_builder.push_storage_change(vec![1, 2, 3], Some(vec![4, 5, 6])).unwrap();
+		let block = block_builder.build().unwrap().block;
+		let header = block.header().clone();
+		let hash = header.hash();
+		let body = Some(block.extrinsics().iter().cloned().collect::<Vec<_>>());
+		let state = ImportedState { block: hash, state: KeyValueStates(Vec::new()) };
+		let justifications = Some(Justifications::from((*b"FRNK", Vec::new())));
+
+		// Prepare `StateSync`
+		let mut state_sync_provider = MockStateSync::<Block>::new();
+		let import = ImportResult::Import(
+			hash,
+			header.clone(),
+			state.clone(),
+			body.clone(),
+			justifications.clone(),
+		);
+		state_sync_provider.expect_import().return_once(move |_| import);
+
+		// Reference values to check against.
+		let expected_origin = BlockOrigin::NetworkInitialSync;
+		let expected_block = IncomingBlock {
+			hash,
+			header: Some(header),
+			body,
+			indexed_body: None,
+			justifications,
+			origin: None,
+			allow_missing_state: true,
+			import_existing: true,
+			skip_execution: true,
+			state: Some(state),
+		};
+		let expected_blocks = vec![expected_block];
+
+		// Prepare `StateStrategy`.
+		let peer_id = PeerId::random();
+		let initial_peers = std::iter::once((peer_id, 10));
+		let mut state_strategy = StateStrategy::new_with_provider(
+			Box::new(state_sync_provider),
+			initial_peers,
+			ProtocolName::Static(""),
+		);
+		// Manually set the peer's state .
+		state_strategy.peers.get_mut(&peer_id).unwrap().state = PeerState::DownloadingState;
+
+		// Receive response.
+		let dummy_response = StateResponse::default().encode_to_vec();
+		state_strategy.on_state_response(&peer_id, dummy_response);
+
+		assert_eq!(state_strategy.actions.len(), 1);
+		assert!(matches!(
+			&state_strategy.actions[0],
+			SyncingAction::ImportBlocks { origin, blocks }
+				if *origin == expected_origin && *blocks == expected_blocks,
+		));
+	}
+
+	#[test]
+	fn importing_unknown_block_doesnt_finish_strategy() {
+		let target_hash = Hash::random();
+		let unknown_hash = Hash::random();
+		let mut state_sync_provider = MockStateSync::<Block>::new();
+		state_sync_provider.expect_target_hash().return_const(target_hash);
+
+		let mut state_strategy = StateStrategy::new_with_provider(
+			Box::new(state_sync_provider),
+			std::iter::empty(),
+			ProtocolName::Static(""),
+		);
+
+		// Unknown block imported.
+		state_strategy.on_blocks_processed(
+			1,
+			1,
+			vec![(
+				Ok(BlockImportStatus::ImportedUnknown(1, ImportedAux::default(), None)),
+				unknown_hash,
+			)],
+		);
+
+		// No actions generated.
+		assert_eq!(state_strategy.actions.len(), 0);
+	}
+
+	#[test]
+	fn successfully_importing_target_block_finishes_strategy() {
+		let target_hash = Hash::random();
+		let mut state_sync_provider = MockStateSync::<Block>::new();
+		state_sync_provider.expect_target_hash().return_const(target_hash);
+
+		let mut state_strategy = StateStrategy::new_with_provider(
+			Box::new(state_sync_provider),
+			std::iter::empty(),
+			ProtocolName::Static(""),
+		);
+
+		// Target block imported.
+		state_strategy.on_blocks_processed(
+			1,
+			1,
+			vec![(
+				Ok(BlockImportStatus::ImportedUnknown(1, ImportedAux::default(), None)),
+				target_hash,
+			)],
+		);
+
+		// Strategy finishes.
+		assert_eq!(state_strategy.actions.len(), 1);
+		assert!(matches!(&state_strategy.actions[0], SyncingAction::Finished));
+	}
+
+	#[test]
+	fn failure_to_import_target_block_finishes_strategy() {
+		let target_hash = Hash::random();
+		let mut state_sync_provider = MockStateSync::<Block>::new();
+		state_sync_provider.expect_target_hash().return_const(target_hash);
+
+		let mut state_strategy = StateStrategy::new_with_provider(
+			Box::new(state_sync_provider),
+			std::iter::empty(),
+			ProtocolName::Static(""),
+		);
+
+		// Target block import failed.
+		state_strategy.on_blocks_processed(
+			1,
+			1,
+			vec![(
+				Err(BlockImportError::VerificationFailed(None, String::from("test-error"))),
+				target_hash,
+			)],
+		);
+
+		// Strategy finishes.
+		assert_eq!(state_strategy.actions.len(), 1);
+		assert!(matches!(&state_strategy.actions[0], SyncingAction::Finished));
+	}
+
+	#[test]
+	fn finished_strategy_doesnt_generate_more_actions() {
+		let target_hash = Hash::random();
+		let mut state_sync_provider = MockStateSync::<Block>::new();
+		state_sync_provider.expect_target_hash().return_const(target_hash);
+		state_sync_provider.expect_is_complete().return_const(true);
+
+		// Get enough peers for possible spurious requests.
+		let initial_peers = (1..=10).map(|best_number| (PeerId::random(), best_number));
+
+		let mut state_strategy = StateStrategy::new_with_provider(
+			Box::new(state_sync_provider),
+			initial_peers,
+			ProtocolName::Static(""),
+		);
+
+		state_strategy.on_blocks_processed(
+			1,
+			1,
+			vec![(
+				Ok(BlockImportStatus::ImportedUnknown(1, ImportedAux::default(), None)),
+				target_hash,
+			)],
+		);
+
+		let network_provider = NetworkServiceProvider::new();
+		let network_handle = network_provider.handle();
+
+		// Strategy finishes.
+		let actions = state_strategy.actions(&network_handle).collect::<Vec<_>>();
+		assert_eq!(actions.len(), 1);
+		assert!(matches!(&actions[0], SyncingAction::Finished));
+
+		// No more actions generated.
+		assert_eq!(state_strategy.actions(&network_handle).count(), 0);
+	}
+}

bizinikiwi/client/network/sync/src/strategy/state_sync.rs

@@ -0,0 +1,343 @@
+// This file is part of Bizinikiwi.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! State sync support.
+
+use crate::{
+	schema::v1::{KeyValueStateEntry, StateEntry, StateRequest, StateResponse},
+	LOG_TARGET,
+};
+use codec::{Decode, Encode};
+use log::debug;
+use pezsc_client_api::{CompactProof, KeyValueStates, ProofProvider};
+use pezsc_consensus::ImportedState;
+use smallvec::SmallVec;
+use pezsp_core::storage::well_known_keys;
+use pezsp_runtime::{
+	traits::{Block as BlockT, Header, NumberFor},
+	Justifications,
+};
+use std::{collections::HashMap, fmt, sync::Arc};
+
+/// Generic state sync provider. Used for mocking in tests.
+pub trait StateSyncProvider<B: BlockT>: Send + Sync {
+	/// Validate and import a state response.
+	fn import(&mut self, response: StateResponse) -> ImportResult<B>;
+	/// Produce next state request.
+	fn next_request(&self) -> StateRequest;
+	/// Check if the state is complete.
+	fn is_complete(&self) -> bool;
+	/// Returns target block number.
+	fn target_number(&self) -> NumberFor<B>;
+	/// Returns target block hash.
+	fn target_hash(&self) -> B::Hash;
+	/// Returns state sync estimated progress.
+	fn progress(&self) -> StateSyncProgress;
+}
+
+// Reported state sync phase.
+#[derive(Clone, Eq, PartialEq, Debug)]
+pub enum StateSyncPhase {
+	// State download in progress.
+	DownloadingState,
+	// Download is complete, state is being imported.
+	ImportingState,
+}
+
+impl fmt::Display for StateSyncPhase {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		match self {
+			Self::DownloadingState => write!(f, "Downloading state"),
+			Self::ImportingState => write!(f, "Importing state"),
+		}
+	}
+}
+
+/// Reported state download progress.
+#[derive(Clone, Eq, PartialEq, Debug)]
+pub struct StateSyncProgress {
+	/// Estimated download percentage.
+	pub percentage: u32,
+	/// Total state size in bytes downloaded so far.
+	pub size: u64,
+	/// Current state sync phase.
+	pub phase: StateSyncPhase,
+}
+
+/// Import state chunk result.
+pub enum ImportResult<B: BlockT> {
+	/// State is complete and ready for import.
+	Import(B::Hash, B::Header, ImportedState<B>, Option<Vec<B::Extrinsic>>, Option<Justifications>),
+	/// Continue downloading.
+	Continue,
+	/// Bad state chunk.
+	BadResponse,
+}
+
+struct StateSyncMetadata<B: BlockT> {
+	last_key: SmallVec<[Vec<u8>; 2]>,
+	target_header: B::Header,
+	target_body: Option<Vec<B::Extrinsic>>,
+	target_justifications: Option<Justifications>,
+	complete: bool,
+	imported_bytes: u64,
+	skip_proof: bool,
+}
+
+impl<B: BlockT> StateSyncMetadata<B> {
+	fn target_hash(&self) -> B::Hash {
+		self.target_header.hash()
+	}
+
+	/// Returns target block number.
+	fn target_number(&self) -> NumberFor<B> {
+		*self.target_header.number()
+	}
+
+	fn target_root(&self) -> B::Hash {
+		*self.target_header.state_root()
+	}
+
+	fn next_request(&self) -> StateRequest {
+		StateRequest {
+			block: self.target_hash().encode(),
+			start: self.last_key.clone().into_vec(),
+			no_proof: self.skip_proof,
+		}
+	}
+
+	fn progress(&self) -> StateSyncProgress {
+		let cursor = *self.last_key.get(0).and_then(|last| last.get(0)).unwrap_or(&0u8);
+		let percent_done = cursor as u32 * 100 / 256;
+		StateSyncProgress {
+			percentage: percent_done,
+			size: self.imported_bytes,
+			phase: if self.complete {
+				StateSyncPhase::ImportingState
+			} else {
+				StateSyncPhase::DownloadingState
+			},
+		}
+	}
+}
+
+/// State sync state machine.
+///
+/// Accumulates partial state data until it is ready to be imported.
+pub struct StateSync<B: BlockT, Client> {
+	metadata: StateSyncMetadata<B>,
+	state: HashMap<Vec<u8>, (Vec<(Vec<u8>, Vec<u8>)>, Vec<Vec<u8>>)>,
+	client: Arc<Client>,
+}
+
+impl<B, Client> StateSync<B, Client>
+where
+	B: BlockT,
+	Client: ProofProvider<B> + Send + Sync + 'static,
+{
+	///  Create a new instance.
+	pub fn new(
+		client: Arc<Client>,
+		target_header: B::Header,
+		target_body: Option<Vec<B::Extrinsic>>,
+		target_justifications: Option<Justifications>,
+		skip_proof: bool,
+	) -> Self {
+		Self {
+			client,
+			metadata: StateSyncMetadata {
+				last_key: SmallVec::default(),
+				target_header,
+				target_body,
+				target_justifications,
+				complete: false,
+				imported_bytes: 0,
+				skip_proof,
+			},
+			state: HashMap::default(),
+		}
+	}
+
+	fn process_state_key_values(
+		&mut self,
+		state_root: Vec<u8>,
+		key_values: impl IntoIterator<Item = (Vec<u8>, Vec<u8>)>,
+	) {
+		let is_top = state_root.is_empty();
+
+		let entry = self.state.entry(state_root).or_default();
+
+		if entry.0.len() > 0 && entry.1.len() > 1 {
+			// Already imported child_trie with same root.
+			// Warning this will not work with parallel download.
+			return;
+		}
+
+		let mut child_storage_roots = Vec::new();
+
+		for (key, value) in key_values {
+			// Skip all child key root (will be recalculated on import)
+			if is_top && well_known_keys::is_child_storage_key(key.as_slice()) {
+				child_storage_roots.push((value, key));
+			} else {
+				self.metadata.imported_bytes += key.len() as u64;
+				entry.0.push((key, value));
+			}
+		}
+
+		for (root, storage_key) in child_storage_roots {
+			self.state.entry(root).or_default().1.push(storage_key);
+		}
+	}
+
+	fn process_state_verified(&mut self, values: KeyValueStates) {
+		for values in values.0 {
+			self.process_state_key_values(values.state_root, values.key_values);
+		}
+	}
+
+	fn process_state_unverified(&mut self, response: StateResponse) -> bool {
+		let mut complete = true;
+		// if the trie is a child trie and one of its parent trie is empty,
+		// the parent cursor stays valid.
+		// Empty parent trie content only happens when all the response content
+		// is part of a single child trie.
+		if self.metadata.last_key.len() == 2 && response.entries[0].entries.is_empty() {
+			// Do not remove the parent trie position.
+			self.metadata.last_key.pop();
+		} else {
+			self.metadata.last_key.clear();
+		}
+		for state in response.entries {
+			debug!(
+				target: LOG_TARGET,
+				"Importing state from {:?} to {:?}",
+				state.entries.last().map(|e| pezsp_core::hexdisplay::HexDisplay::from(&e.key)),
+				state.entries.first().map(|e| pezsp_core::hexdisplay::HexDisplay::from(&e.key)),
+			);
+
+			if !state.complete {
+				if let Some(e) = state.entries.last() {
+					self.metadata.last_key.push(e.key.clone());
+				}
+				complete = false;
+			}
+
+			let KeyValueStateEntry { state_root, entries, complete: _ } = state;
+			self.process_state_key_values(
+				state_root,
+				entries.into_iter().map(|StateEntry { key, value }| (key, value)),
+			);
+		}
+		complete
+	}
+}
+
+impl<B, Client> StateSyncProvider<B> for StateSync<B, Client>
+where
+	B: BlockT,
+	Client: ProofProvider<B> + Send + Sync + 'static,
+{
+	///  Validate and import a state response.
+	fn import(&mut self, response: StateResponse) -> ImportResult<B> {
+		if response.entries.is_empty() && response.proof.is_empty() {
+			debug!(target: LOG_TARGET, "Bad state response");
+			return ImportResult::BadResponse;
+		}
+		if !self.metadata.skip_proof && response.proof.is_empty() {
+			debug!(target: LOG_TARGET, "Missing proof");
+			return ImportResult::BadResponse;
+		}
+		let complete = if !self.metadata.skip_proof {
+			debug!(target: LOG_TARGET, "Importing state from {} trie nodes", response.proof.len());
+			let proof_size = response.proof.len() as u64;
+			let proof = match CompactProof::decode(&mut response.proof.as_ref()) {
+				Ok(proof) => proof,
+				Err(e) => {
+					debug!(target: LOG_TARGET, "Error decoding proof: {:?}", e);
+					return ImportResult::BadResponse;
+				},
+			};
+			let (values, completed) = match self.client.verify_range_proof(
+				self.metadata.target_root(),
+				proof,
+				self.metadata.last_key.as_slice(),
+			) {
+				Err(e) => {
+					debug!(
+						target: LOG_TARGET,
+						"StateResponse failed proof verification: {}",
+						e,
+					);
+					return ImportResult::BadResponse;
+				},
+				Ok(values) => values,
+			};
+			debug!(target: LOG_TARGET, "Imported with {} keys", values.len());
+
+			let complete = completed == 0;
+			if !complete && !values.update_last_key(completed, &mut self.metadata.last_key) {
+				debug!(target: LOG_TARGET, "Error updating key cursor, depth: {}", completed);
+			};
+
+			self.process_state_verified(values);
+			self.metadata.imported_bytes += proof_size;
+			complete
+		} else {
+			self.process_state_unverified(response)
+		};
+		if complete {
+			self.metadata.complete = true;
+			let target_hash = self.metadata.target_hash();
+			ImportResult::Import(
+				target_hash,
+				self.metadata.target_header.clone(),
+				ImportedState { block: target_hash, state: std::mem::take(&mut self.state).into() },
+				self.metadata.target_body.clone(),
+				self.metadata.target_justifications.clone(),
+			)
+		} else {
+			ImportResult::Continue
+		}
+	}
+
+	/// Produce next state request.
+	fn next_request(&self) -> StateRequest {
+		self.metadata.next_request()
+	}
+
+	/// Check if the state is complete.
+	fn is_complete(&self) -> bool {
+		self.metadata.complete
+	}
+
+	/// Returns target block number.
+	fn target_number(&self) -> NumberFor<B> {
+		self.metadata.target_number()
+	}
+
+	/// Returns target block hash.
+	fn target_hash(&self) -> B::Hash {
+		self.metadata.target_hash()
+	}
+
+	/// Returns state sync estimated progress.
+	fn progress(&self) -> StateSyncProgress {
+		self.metadata.progress()
+	}
+}