Some refactoring in network-bridge in the course of dealing with #2177 (#2263)

* More doc fixes.

* Minor refactorings in the process of #2177

By having everything peer set related depend directly on the enum the
code becomes more clear and it is also straight forward to add more
peersets/protocols as the compiler will complain if you forget to
implement parts of it.

* Add peer set infos on startup properly

For feature real_overseer.

+ Fixes from review. Thanks @coriolinus and @ordian!

* More structure in network-bridge

Some changes, which would have helped me in groking the code faster.

Entry points/public types more to the top. Factored out implementation
in their own files, to clear up the top-level view.

* Get rid of local ProtocolName type definition.

Does not add much at this level.

* Fix tests + import cleanup.

* Make spaces tabs.

* Clarify what correct parameters to send_message are

* Be more less vague in docs of send_message.

* Apply suggestions from code review

Extend copyright on new files to 2021 as well.

Co-authored-by: Andronik Ordian <write@reusable.software>

Co-authored-by: Andronik Ordian <write@reusable.software>

polkadot/node/network/protocol/src/lib.rs

@@ -29,6 +29,10 @@ pub use polkadot_node_jaeger::JaegerSpan;
 #[doc(hidden)]
 pub use std::sync::Arc;
 
+
+/// Peer-sets and protocols used for parachains.
+pub mod peer_set;
+
 /// A unique identifier of a request.
 pub type RequestId = u64;
 
@@ -47,15 +51,6 @@ impl fmt::Display for WrongVariant {
 
 impl std::error::Error for WrongVariant {}
 
-/// The peer-sets that the network manages. Different subsystems will use different peer-sets.
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum PeerSet {
-	/// The validation peer-set is responsible for all messages related to candidate validation and communication among validators.
-	Validation,
-	/// The collation peer-set is used for validator<>collator communication.
-	Collation,
-}
-
 /// The advertised role of a node.
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub enum ObservedRole {

polkadot/node/network/protocol/src/peer_set.rs

@@ -0,0 +1,90 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot 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.
+
+// Polkadot 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 Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! All peersets and protocols used for parachains.
+
+use sc_network::config::{NonDefaultSetConfig, SetConfig};
+use std::borrow::Cow;
+use strum::{EnumIter, IntoEnumIterator};
+
+/// The peer-sets and thus the protocols which are used for the network.
+#[derive(Debug, Clone, Copy, PartialEq, EnumIter)]
+pub enum PeerSet {
+	/// The validation peer-set is responsible for all messages related to candidate validation and communication among validators.
+	Validation,
+	/// The collation peer-set is used for validator<>collator communication.
+	Collation,
+}
+
+impl PeerSet {
+	/// Get `sc_network` peer set configurations for each peerset.
+	///
+	/// Those should be used in the network configuration to register the protocols with the
+	/// network service.
+	pub fn get_info(self) -> NonDefaultSetConfig {
+		let protocol = self.into_protocol_name();
+		match self {
+			PeerSet::Validation => NonDefaultSetConfig {
+				notifications_protocol: protocol,
+				set_config: sc_network::config::SetConfig {
+					in_peers: 25,
+					out_peers: 0,
+					reserved_nodes: Vec::new(),
+					non_reserved_mode: sc_network::config::NonReservedPeerMode::Accept,
+				},
+			},
+			PeerSet::Collation => NonDefaultSetConfig {
+				notifications_protocol: protocol,
+				set_config: SetConfig {
+					in_peers: 25,
+					out_peers: 0,
+					reserved_nodes: Vec::new(),
+					non_reserved_mode: sc_network::config::NonReservedPeerMode::Accept,
+				},
+			},
+		}
+	}
+
+	/// Get the protocol name associated with each peer set as static str.
+	pub const fn get_protocol_name_static(self) -> &'static str {
+		match self {
+			PeerSet::Validation => "/polkadot/validation/1",
+			PeerSet::Collation => "/polkadot/collation/1",
+		}
+	}
+
+	/// Convert a peer set into a protocol name as understood by Substrate.
+	pub fn into_protocol_name(self) -> Cow<'static, str> {
+		self.get_protocol_name_static().into()
+	}
+
+	/// Try parsing a protocol name into a peer set.
+	pub fn try_from_protocol_name(name: &Cow<'static, str>) -> Option<PeerSet> {
+		match name {
+			n if n == &PeerSet::Validation.into_protocol_name() => Some(PeerSet::Validation),
+			n if n == &PeerSet::Collation.into_protocol_name() => Some(PeerSet::Collation),
+			_ => None,
+		}
+	}
+}
+
+/// Get `NonDefaultSetConfig`s for all available peer sets.
+///
+/// Should be used during network configuration (added to [`NetworkConfiguration::extra_sets`])
+/// or shortly after startup to register the protocols with the network service.
+pub fn peer_sets_info() -> Vec<sc_network::config::NonDefaultSetConfig> {
+	PeerSet::iter().map(PeerSet::get_info).collect()
+}