Storage chains: serve transactions over IPFS/bitswap (#7963)

* IPFS server for transactions

* Style

* Indent

* Log message

* CLI option

* Apply suggestions from code review

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>

* Style

* Style

* Minor fixes

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>

substrate/Cargo.lock

@@ -362,6 +362,12 @@ dependencies = [
  "rustc-demangle",
 ]
 
+[[package]]
+name = "base-x"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4521f3e3d031370679b3b140beb36dfe4801b09ac77e30c61941f97df3ef28b"
+
 [[package]]
 name = "base58"
 version = "0.1.0"
@@ -464,6 +470,32 @@ dependencies = [
  "constant_time_eq",
 ]
 
+[[package]]
+name = "blake2s_simd"
+version = "0.5.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9e461a7034e85b211a4acb57ee2e6730b32912b06c08cc242243c39fc21ae6a2"
+dependencies = [
+ "arrayref",
+ "arrayvec 0.5.2",
+ "constant_time_eq",
+]
+
+[[package]]
+name = "blake3"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e9ff35b701f3914bdb8fad3368d822c766ef2858b2583198e41639b936f09d3f"
+dependencies = [
+ "arrayref",
+ "arrayvec 0.5.2",
+ "cc",
+ "cfg-if 0.1.10",
+ "constant_time_eq",
+ "crypto-mac 0.8.0",
+ "digest 0.9.0",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.7.3"
@@ -706,6 +738,17 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "cid"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d88f30b1e74e7063df5711496f3ee6e74a9735d62062242d70cddf77717f18e"
+dependencies = [
+ "multibase",
+ "multihash",
+ "unsigned-varint 0.5.1",
+]
+
 [[package]]
 name = "cipher"
 version = "0.2.5"
@@ -1163,6 +1206,26 @@ version = "2.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "993a608597367c6377b258c25d7120740f00ed23a2252b729b1932dd7866f908"
 
+[[package]]
+name = "data-encoding-macro"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0a94feec3d2ba66c0b6621bca8bc6f68415b1e5c69af3586fdd0af9fd9f29b17"
+dependencies = [
+ "data-encoding",
+ "data-encoding-macro-internal",
+]
+
+[[package]]
+name = "data-encoding-macro-internal"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0f83e699727abca3c56e187945f303389590305ab2f0185ea445aa66e8d5f2a"
+dependencies = [
+ "data-encoding",
+ "syn",
+]
+
 [[package]]
 name = "derive_more"
 version = "0.99.11"
@@ -3580,16 +3643,31 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0debeb9fcf88823ea64d64e4a815ab1643f33127d995978e099942ce38f25238"
 
+[[package]]
+name = "multibase"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b78c60039650ff12e140ae867ef5299a58e19dded4d334c849dc7177083667e2"
+dependencies = [
+ "base-x",
+ "data-encoding",
+ "data-encoding-macro",
+]
+
 [[package]]
 name = "multihash"
 version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fb63389ee5fcd4df3f8727600f4a0c3df53c541f0ed4e8b50a9ae51a80fc1efe"
 dependencies = [
+ "blake2b_simd",
+ "blake2s_simd",
+ "blake3",
  "digest 0.9.0",
  "generic-array 0.14.4",
  "multihash-derive",
  "sha2 0.9.2",
+ "sha3",
  "unsigned-varint 0.5.1",
 ]
 
@@ -7105,6 +7183,7 @@ dependencies = [
  "bitflags",
  "bs58",
  "bytes 1.0.1",
+ "cid",
  "derive_more",
  "either",
  "erased-serde",

substrate/client/api/src/client.rs

@@ -95,6 +95,17 @@ pub trait BlockBackend<Block: BlockT> {
 
 	/// Get block hash by number.
 	fn block_hash(&self, number: NumberFor<Block>) -> sp_blockchain::Result<Option<Block::Hash>>;
+
+	/// Get single extrinsic by hash.
+	fn extrinsic(
+		&self,
+		hash: &Block::Hash,
+	) -> sp_blockchain::Result<Option<<Block as BlockT>::Extrinsic>>;
+
+	/// Check if extrinsic exists.
+	fn have_extrinsic(&self, hash: &Block::Hash) -> sp_blockchain::Result<bool> {
+		Ok(self.extrinsic(hash)?.is_some())
+	}
 }
 
 /// Provide a list of potential uncle headers for a given block.

substrate/client/api/src/in_mem.rs

@@ -386,6 +386,13 @@ impl<Block: BlockT> blockchain::Backend<Block> for Blockchain<Block> {
 	fn children(&self, _parent_hash: Block::Hash) -> sp_blockchain::Result<Vec<Block::Hash>> {
 		unimplemented!()
 	}
+
+	fn extrinsic(
+		&self,
+		_hash: &Block::Hash,
+	) -> sp_blockchain::Result<Option<<Block as BlockT>::Extrinsic>> {
+		unimplemented!("Not supported by the in-mem backend.")
+	}
 }
 
 impl<Block: BlockT> blockchain::ProvideCache<Block> for Blockchain<Block> {

substrate/client/cli/src/params/network_params.rs

@@ -110,6 +110,10 @@ pub struct NetworkParams {
 	/// security improvements.
 	#[structopt(long)]
 	pub kademlia_disjoint_query_paths: bool,
+
+	/// Join the IPFS network and serve transactions over bitswap protocol.
+	#[structopt(long)]
+	pub ipfs_server: bool,
 }
 
 impl NetworkParams {
@@ -181,6 +185,7 @@ impl NetworkParams {
 			allow_non_globals_in_dht,
 			kademlia_disjoint_query_paths: self.kademlia_disjoint_query_paths,
 			yamux_window_size: None,
+			ipfs_server: self.ipfs_server,
 		}
 	}
 }

substrate/client/db/src/lib.rs

@@ -448,20 +448,6 @@ impl<Block: BlockT> BlockchainDb<Block> {
 				header.digest().log(DigestItem::as_changes_trie_root)
 					.cloned()))
 	}
-
-	fn extrinsic(&self, hash: &Block::Hash) -> ClientResult<Option<Block::Extrinsic>> {
-		match self.db.get(columns::TRANSACTION, hash.as_ref()) {
-			Some(ex) => {
-				match Decode::decode(&mut &ex[..]) {
-					Ok(ex) => Ok(Some(ex)),
-					Err(err) => Err(sp_blockchain::Error::Backend(
-						format!("Error decoding extrinsic {}: {}", hash, err)
-					)),
-				}
-			},
-			None => Ok(None),
-		}
-	}
 }
 
 impl<Block: BlockT> sc_client_api::blockchain::HeaderBackend<Block> for BlockchainDb<Block> {
@@ -532,7 +518,7 @@ impl<Block: BlockT> sc_client_api::blockchain::Backend<Block> for BlockchainDb<B
 						match Vec::<Block::Hash>::decode(&mut &body[..]) {
 							Ok(hashes) => {
 								let extrinsics: ClientResult<Vec<Block::Extrinsic>> = hashes.into_iter().map(
-									|h| self.extrinsic(&h) .and_then(|maybe_ex| maybe_ex.ok_or_else(
+									|h| self.extrinsic(&h).and_then(|maybe_ex| maybe_ex.ok_or_else(
 										|| sp_blockchain::Error::Backend(
 											format!("Missing transaction: {}", h))))
 								).collect();
@@ -576,6 +562,24 @@ impl<Block: BlockT> sc_client_api::blockchain::Backend<Block> for BlockchainDb<B
 	fn children(&self, parent_hash: Block::Hash) -> ClientResult<Vec<Block::Hash>> {
 		children::read_children(&*self.db, columns::META, meta_keys::CHILDREN_PREFIX, parent_hash)
 	}
+
+	fn extrinsic(&self, hash: &Block::Hash) -> ClientResult<Option<Block::Extrinsic>> {
+		match self.db.get(columns::TRANSACTION, hash.as_ref()) {
+			Some(ex) => {
+				match Decode::decode(&mut &ex[..]) {
+					Ok(ex) => Ok(Some(ex)),
+					Err(err) => Err(sp_blockchain::Error::Backend(
+							format!("Error decoding extrinsic {}: {}", hash, err)
+					)),
+				}
+			},
+			None => Ok(None),
+		}
+	}
+
+	fn have_extrinsic(&self, hash: &Block::Hash) -> ClientResult<bool> {
+		Ok(self.db.contains(columns::TRANSACTION, hash.as_ref()))
+	}
 }
 
 impl<Block: BlockT> sc_client_api::blockchain::ProvideCache<Block> for BlockchainDb<Block> {

substrate/client/db/src/utils.rs

@@ -401,7 +401,13 @@ pub fn read_meta<Block>(db: &dyn Database<DbHash>, col_header: u32) -> Result<
 			}
 		{
 			let hash = header.hash();
-			debug!("DB Opened blockchain db, fetched {} = {:?} ({})", desc, hash, header.number());
+			debug!(
+				target: "db",
+				"Opened blockchain db, fetched {} = {:?} ({})",
+				desc,
+				hash,
+				header.number()
+			);
 			Ok((hash, *header.number()))
 		} else {
 			Ok((genesis_hash.clone(), Zero::zero()))

substrate/client/light/src/blockchain.rs

@@ -128,6 +128,13 @@ impl<S, Block> BlockchainBackend<Block> for Blockchain<S> where Block: BlockT, S
 	fn children(&self, _parent_hash: Block::Hash) -> ClientResult<Vec<Block::Hash>> {
 		Err(ClientError::NotAvailableOnLightClient)
 	}
+
+	fn extrinsic(
+		&self,
+		_hash: &Block::Hash,
+	) -> ClientResult<Option<<Block as BlockT>::Extrinsic>> {
+		Err(ClientError::NotAvailableOnLightClient)
+	}
 }
 
 impl<S: Storage<Block>, Block: BlockT> ProvideCache<Block> for Blockchain<S> {

substrate/client/network/Cargo.toml

@@ -21,6 +21,7 @@ async-trait = "0.1"
 async-std = "1.6.5"
 bitflags = "1.2.0"
 bs58 = "0.4.0"
+cid = "0.6.0"
 bytes = "1"
 codec = { package = "parity-scale-codec", version = "2.0.0", features = ["derive"] }
 derive_more = "0.99.2"

substrate/client/network/build.rs

@@ -1,6 +1,7 @@
 const PROTOS: &[&str] = &[
 	"src/schema/api.v1.proto",
-	"src/schema/light.v1.proto"
+	"src/schema/light.v1.proto",
+	"src/schema/bitswap.v1.2.0.proto",
 ];
 
 fn main() {

substrate/client/network/src/behaviour.rs

@@ -18,6 +18,7 @@
 
 use crate::{
 	config::{ProtocolId, Role},
+	bitswap::Bitswap,
 	discovery::{DiscoveryBehaviour, DiscoveryConfig, DiscoveryOut},
 	protocol::{message::Roles, CustomMessageOutcome, NotificationsSink, Protocol},
 	peer_info, request_responses, light_client_requests,
@@ -30,7 +31,9 @@ use libp2p::NetworkBehaviour;
 use libp2p::core::{Multiaddr, PeerId, PublicKey};
 use libp2p::identify::IdentifyInfo;
 use libp2p::kad::record;
-use libp2p::swarm::{NetworkBehaviourAction, NetworkBehaviourEventProcess, PollParameters};
+use libp2p::swarm::{
+	NetworkBehaviourAction, NetworkBehaviourEventProcess, PollParameters, toggle::Toggle
+};
 use log::debug;
 use prost::Message;
 use sp_consensus::{BlockOrigin, import_queue::{IncomingBlock, Origin}};
@@ -59,6 +62,8 @@ pub struct Behaviour<B: BlockT, H: ExHashT> {
 	peer_info: peer_info::PeerInfoBehaviour,
 	/// Discovers nodes of the network.
 	discovery: DiscoveryBehaviour,
+	/// Bitswap server for blockchain data.
+	bitswap: Toggle<Bitswap<B>>,
 	/// Generic request-reponse protocols.
 	request_responses: request_responses::RequestResponsesBehaviour,
 
@@ -181,6 +186,7 @@ impl<B: BlockT, H: ExHashT> Behaviour<B, H> {
 		light_client_request_sender: light_client_requests::sender::LightClientRequestSender<B>,
 		disco_config: DiscoveryConfig,
 		block_request_protocol_config: request_responses::ProtocolConfig,
+		bitswap: Option<Bitswap<B>>,
 		light_client_request_protocol_config: request_responses::ProtocolConfig,
 		// All remaining request protocol configs.
 		mut request_response_protocols: Vec<request_responses::ProtocolConfig>,
@@ -195,6 +201,7 @@ impl<B: BlockT, H: ExHashT> Behaviour<B, H> {
 			substrate,
 			peer_info: peer_info::PeerInfoBehaviour::new(user_agent, local_public_key),
 			discovery: disco_config.finish(),
+			bitswap: bitswap.into(),
 			request_responses:
 				request_responses::RequestResponsesBehaviour::new(request_response_protocols.into_iter())?,
 			light_client_request_sender,
@@ -299,6 +306,13 @@ fn reported_roles_to_observed_role(local_role: &Role, remote: &PeerId, roles: Ro
 	}
 }
 
+impl<B: BlockT, H: ExHashT> NetworkBehaviourEventProcess<void::Void> for
+Behaviour<B, H> {
+	fn inject_event(&mut self, event: void::Void) {
+		void::unreachable(event)
+	}
+}
+
 impl<B: BlockT, H: ExHashT> NetworkBehaviourEventProcess<CustomMessageOutcome<B>> for
 Behaviour<B, H> {
 	fn inject_event(&mut self, event: CustomMessageOutcome<B>) {

substrate/client/network/src/bitswap.rs

@@ -0,0 +1,338 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate 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.
+
+// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Bitswap server for substrate.
+//!
+//! 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 std::collections::VecDeque;
+use std::io;
+use std::sync::Arc;
+use std::task::{Context, Poll};
+use cid::Version;
+use codec::Encode;
+use core::pin::Pin;
+use futures::Future;
+use futures::io::{AsyncRead, AsyncWrite};
+use libp2p::core::{
+	connection::ConnectionId, Multiaddr, PeerId,
+	upgrade, InboundUpgrade, OutboundUpgrade, UpgradeInfo,
+};
+use libp2p::swarm::{
+	NetworkBehaviour, NetworkBehaviourAction, NotifyHandler, PollParameters,
+	ProtocolsHandler, IntoProtocolsHandler, OneShotHandler,
+};
+use log::{error, debug, trace};
+use prost::Message;
+use sp_runtime::traits::{Block as BlockT};
+use unsigned_varint::{encode as varint_encode};
+use crate::chain::Client;
+use crate::schema::bitswap::{
+	Message as BitswapMessage,
+	message::{wantlist::WantType, Block as MessageBlock, BlockPresenceType, BlockPresence},
+};
+
+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 substrate protocol message
+const MAX_PACKET_SIZE: usize = 16 * 1024 * 1024;
+
+// Max number of queued responses before denying requests.
+const MAX_RESPONSE_QUEUE: usize = 20;
+// Max number of blocks per wantlist
+const MAX_WANTED_BLOCKS: usize = 16;
+
+const PROTOCOL_NAME: &'static [u8] = b"/ipfs/bitswap/1.2.0";
+
+type FutureResult<T, E> = Pin<Box<dyn Future<Output = Result<T, E>> + Send>>;
+
+/// Bitswap protocol config
+#[derive(Clone, Copy, Debug, Default)]
+pub struct BitswapConfig;
+
+impl UpgradeInfo for BitswapConfig {
+	type Info = &'static [u8];
+	type InfoIter = std::iter::Once<Self::Info>;
+
+	fn protocol_info(&self) -> Self::InfoIter {
+		std::iter::once(PROTOCOL_NAME)
+	}
+}
+
+impl<TSocket> InboundUpgrade<TSocket> for BitswapConfig
+where
+	TSocket: AsyncRead + AsyncWrite + Send + Unpin + 'static,
+{
+	type Output = BitswapMessage;
+	type Error = BitswapError;
+	type Future = FutureResult<Self::Output, Self::Error>;
+
+	fn upgrade_inbound(self, mut socket: TSocket, _info: Self::Info) -> Self::Future {
+		Box::pin(async move {
+			let packet = upgrade::read_one(&mut socket, MAX_PACKET_SIZE).await?;
+			let message: BitswapMessage = Message::decode(packet.as_slice())?;
+			Ok(message)
+		})
+	}
+}
+
+impl UpgradeInfo for BitswapMessage {
+	type Info = &'static [u8];
+	type InfoIter = std::iter::Once<Self::Info>;
+
+	fn protocol_info(&self) -> Self::InfoIter {
+		std::iter::once(PROTOCOL_NAME)
+	}
+}
+
+impl<TSocket> OutboundUpgrade<TSocket> for BitswapMessage
+where
+	TSocket: AsyncRead + AsyncWrite + Send + Unpin + 'static,
+{
+	type Output = ();
+	type Error = io::Error;
+	type Future = FutureResult<Self::Output, Self::Error>;
+
+	fn upgrade_outbound(self, mut socket: TSocket, _info: Self::Info) -> Self::Future {
+		Box::pin(async move {
+			let mut data = Vec::with_capacity(self.encoded_len());
+			self.encode(&mut data)?;
+			upgrade::write_one(&mut socket, data).await
+		})
+	}
+}
+
+/// Internal protocol handler event.
+#[derive(Debug)]
+pub enum HandlerEvent {
+	/// We received a `BitswapMessage` from a remote.
+	Request(BitswapMessage),
+	/// We successfully sent a `BitswapMessage`.
+	ResponseSent,
+}
+
+impl From<BitswapMessage> for HandlerEvent {
+	fn from(message: BitswapMessage) -> Self {
+		Self::Request(message)
+	}
+}
+
+impl From<()> for HandlerEvent {
+	fn from(_: ()) -> Self {
+		Self::ResponseSent
+	}
+}
+
+/// 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.into(), &mut buf);
+		res.extend_from_slice(codec);
+		let mut buf = varint_encode::u64_buffer();
+		let mh_type = varint_encode::u64(self.mh_type.into(), &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
+	}
+}
+
+/// Network behaviour that handles sending and receiving IPFS blocks.
+pub struct Bitswap<B> {
+	client: Arc<dyn Client<B>>,
+	ready_blocks: VecDeque<(PeerId, BitswapMessage)>,
+}
+
+impl<B: BlockT> Bitswap<B> {
+	/// Create a new instance of the bitswap protocol handler.
+	pub fn new(client: Arc<dyn Client<B>>) -> Self {
+		Bitswap {
+			client,
+			ready_blocks: Default::default(),
+		}
+	}
+}
+
+impl<B: BlockT> NetworkBehaviour for Bitswap<B> {
+	type ProtocolsHandler = OneShotHandler<BitswapConfig, BitswapMessage, HandlerEvent>;
+	type OutEvent = void::Void;
+
+	fn new_handler(&mut self) -> Self::ProtocolsHandler {
+		Default::default()
+	}
+
+	fn addresses_of_peer(&mut self, _peer: &PeerId) -> Vec<Multiaddr> {
+		Vec::new()
+	}
+
+	fn inject_connected(&mut self, _peer: &PeerId) {
+	}
+
+	fn inject_disconnected(&mut self, _peer: &PeerId) {
+	}
+
+	fn inject_event(&mut self, peer: PeerId, _connection: ConnectionId, message: HandlerEvent) {
+		let request = match message {
+			HandlerEvent::ResponseSent => return,
+			HandlerEvent::Request(msg) => msg,
+		};
+		trace!(target: LOG_TARGET, "Received request: {:?} from {}", request, peer);
+		if self.ready_blocks.len() > MAX_RESPONSE_QUEUE {
+			debug!(target: LOG_TARGET, "Ignored request: queue is full");
+			return;
+		}
+		let mut response = BitswapMessage {
+			wantlist: None,
+			blocks: Default::default(),
+			payload: Default::default(),
+			block_presences: Default::default(),
+			pending_bytes: 0,
+		};
+		let wantlist = match request.wantlist {
+			Some(wantlist) => wantlist,
+			None => {
+				debug!(
+					target: LOG_TARGET,
+					"Unexpected bitswap message from {}",
+					peer,
+				);
+				return;
+			}
+		};
+		if wantlist.entries.len() > MAX_WANTED_BLOCKS {
+			trace!(target: LOG_TARGET, "Ignored request: too many entries");
+			return;
+		}
+		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 extrinsic = match self.client.extrinsic(&hash) {
+				Ok(ex) => ex,
+				Err(e) => {
+					error!(target: LOG_TARGET, "Error retrieving extrinsic {}: {}", hash, e);
+					None
+				}
+			};
+			match extrinsic {
+				Some(extrinsic) => {
+					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: extrinsic.encode(),
+						});
+					} 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(),
+						});
+					}
+				}
+			}
+		}
+		trace!(target: LOG_TARGET, "Response: {:?}", response);
+		self.ready_blocks.push_back((peer, response));
+	}
+
+	fn poll(&mut self, _ctx: &mut Context, _: &mut impl PollParameters) -> Poll<
+		NetworkBehaviourAction<
+			<<Self::ProtocolsHandler as IntoProtocolsHandler>::Handler as ProtocolsHandler>::InEvent,
+			Self::OutEvent,
+		>,
+	> {
+		if let Some((peer_id, message)) = self.ready_blocks.pop_front() {
+			return Poll::Ready(NetworkBehaviourAction::NotifyHandler {
+				peer_id: peer_id.clone(),
+				handler: NotifyHandler::Any,
+				event: message,
+			})
+		}
+		Poll::Pending
+	}
+}
+
+/// Bitswap protocol error.
+#[derive(derive_more::Display, derive_more::From)]
+pub enum BitswapError {
+	/// Protobuf decoding error.
+	#[display(fmt = "Failed to decode request: {}.", _0)]
+	DecodeProto(prost::DecodeError),
+	/// Protobuf encoding error.
+	#[display(fmt = "Failed to encode response: {}.", _0)]
+	EncodeProto(prost::EncodeError),
+	/// Client backend error.
+	Client(sp_blockchain::Error),
+	/// Error parsing CID
+	BadCid(cid::Error),
+	/// Packet read error.
+	Read(upgrade::ReadOneError),
+	/// Error sending response.
+	#[display(fmt = "Failed to send response.")]
+	SendResponse,
+}

substrate/client/network/src/config.rs

@@ -420,6 +420,8 @@ pub struct NetworkConfiguration {
 	/// 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,
+	/// Enable serving block data over IPFS bitswap.
+	pub ipfs_server: bool,
 
 	/// Size of Yamux receive window of all substreams. `None` for the default (256kiB).
 	/// Any value less than 256kiB is invalid.
@@ -472,6 +474,7 @@ impl NetworkConfiguration {
 			allow_non_globals_in_dht: false,
 			kademlia_disjoint_query_paths: false,
 			yamux_window_size: None,
+			ipfs_server: false,
 		}
 	}
 

substrate/client/network/src/lib.rs

@@ -258,6 +258,7 @@ mod transport;
 mod utils;
 
 pub mod block_request_handler;
+pub mod bitswap;
 pub mod light_client_requests;
 pub mod config;
 pub mod error;

substrate/client/network/src/schema.rs

@@ -24,3 +24,7 @@ pub mod v1 {
 		include!(concat!(env!("OUT_DIR"), "/api.v1.light.rs"));
 	}
 }
+
+pub mod bitswap {
+	include!(concat!(env!("OUT_DIR"), "/bitswap.message.rs"));
+}

substrate/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;
+}

substrate/client/network/src/service.rs

@@ -50,6 +50,7 @@ use crate::{
 		sync::SyncState,
 	},
 	transport, ReputationChange,
+	bitswap::Bitswap,
 };
 use futures::{channel::oneshot, prelude::*};
 use libp2p::{PeerId, multiaddr, Multiaddr};
@@ -248,6 +249,7 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkWorker<B, H> {
 		let is_major_syncing = Arc::new(AtomicBool::new(false));
 
 		// Build the swarm.
+		let client = params.chain.clone();
 		let (mut swarm, bandwidth): (Swarm<B, H>, _) = {
 			let user_agent = format!(
 				"{} ({})",
@@ -334,6 +336,7 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkWorker<B, H> {
 			};
 
 			let behaviour = {
+				let bitswap = if params.network_config.ipfs_server { Some(Bitswap::new(client)) } else { None };
 				let result = Behaviour::new(
 					protocol,
 					params.role,
@@ -342,6 +345,7 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkWorker<B, H> {
 					light_client_request_sender,
 					discovery_config,
 					params.block_request_protocol_config,
+					bitswap,
 					params.light_client_request_protocol_config,
 					params.network_config.request_response_protocols,
 				);
@@ -1638,11 +1642,11 @@ impl<B: BlockT + 'static, H: ExHashT> Future for NetworkWorker<B, H> {
 						let reason = match cause {
 							Some(ConnectionError::IO(_)) => "transport-error",
 							Some(ConnectionError::Handler(NodeHandlerWrapperError::Handler(EitherError::A(EitherError::A(
-								EitherError::B(EitherError::A(
+								EitherError::A(EitherError::B(EitherError::A(
-								PingFailure::Timeout))))))) => "ping-timeout",
+								PingFailure::Timeout)))))))) => "ping-timeout",
 							Some(ConnectionError::Handler(NodeHandlerWrapperError::Handler(EitherError::A(EitherError::A(
-								EitherError::A(
+								EitherError::A(EitherError::A(
-								NotifsHandlerError::SyncNotificationsClogged)))))) => "sync-notifications-clogged",
+								NotifsHandlerError::SyncNotificationsClogged))))))) => "sync-notifications-clogged",
 							Some(ConnectionError::Handler(NodeHandlerWrapperError::Handler(_))) => "protocol-error",
 							Some(ConnectionError::Handler(NodeHandlerWrapperError::KeepAliveTimeout)) => "keep-alive-timeout",
 							None => "actively-closed",

substrate/client/service/src/client/client.rs

@@ -1919,6 +1919,14 @@ impl<B, E, Block, RA> BlockBackend<Block> for Client<B, E, Block, RA>
 	fn block_hash(&self, number: NumberFor<Block>) -> sp_blockchain::Result<Option<Block::Hash>> {
 		self.backend.blockchain().hash(number)
 	}
+
+	fn extrinsic(&self, hash: &Block::Hash) -> sp_blockchain::Result<Option<Block::Extrinsic>> {
+		self.backend.blockchain().extrinsic(hash)
+	}
+
+	fn have_extrinsic(&self, hash: &Block::Hash) -> sp_blockchain::Result<bool> {
+		self.backend.blockchain().have_extrinsic(hash)
+	}
 }
 
 impl<B, E, Block, RA> backend::AuxStore for Client<B, E, Block, RA>

substrate/primitives/blockchain/src/backend.rs

@@ -215,6 +215,17 @@ pub trait Backend<Block: BlockT>: HeaderBackend<Block> + HeaderMetadata<Block, E
 
 		Ok(None)
 	}
+
+	/// Get single extrinsic by hash.
+	fn extrinsic(
+		&self,
+		hash: &Block::Hash,
+	) -> Result<Option<<Block as BlockT>::Extrinsic>>;
+
+	/// Check if extrinsic exists.
+	fn have_extrinsic(&self, hash: &Block::Hash) -> Result<bool> {
+		Ok(self.extrinsic(hash)?.is_some())
+	}
 }
 
 /// Provides access to the optional cache.

substrate/primitives/database/src/lib.rs

@@ -115,6 +115,11 @@ pub trait Database<H: Clone>: Send + Sync {
 	/// `key` is not currently in the database.
 	fn get(&self, col: ColumnId, key: &[u8]) -> Option<Vec<u8>>;
 
+	/// Check if the value exists in the database without retrieving it.
+	fn contains(&self, col: ColumnId, key: &[u8]) -> bool {
+		self.get(col, key).is_some()
+	}
+
 	/// Call `f` with the value previously stored against `key`.
 	///
 	/// This may be faster than `get` since it doesn't allocate.