sc-network: expose add_to_priority_group and `remove_from_priority_… (#7247)

* sc-network: expose `add_to_priority_group` and `remove_from_priority_group` in `NetworkService`

* sc-network: fix a typo

* Update client/network/src/service.rs

Co-authored-by: Max Inden <mail@max-inden.de>

* s/parse_multiaddr/split_multiaddr_and_peer_id/g

* sc-network: mark new functions as async and add comments

* Apply suggestions from code review

Co-authored-by: Max Inden <mail@max-inden.de>

Co-authored-by: Max Inden <mail@max-inden.de>

substrate/client/network/src/service.rs

@@ -973,23 +973,7 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkService<B, H> {
 	/// Returns an `Err` if one of the given addresses is invalid or contains an
 	/// invalid peer ID (which includes the local peer ID).
 	pub fn set_priority_group(&self, group_id: String, peers: HashSet<Multiaddr>) -> Result<(), String> {
-		let peers = peers.into_iter()
+		let peers = self.split_multiaddr_and_peer_id(peers)?;
-			.map(|mut addr| {
-				let peer = match addr.pop() {
-					Some(multiaddr::Protocol::P2p(key)) => PeerId::from_multihash(key)
-						.map_err(|_| "Invalid PeerId format".to_string())?,
-					_ => return Err("Missing PeerId from address".to_string()),
-				};
-
-				// Make sure the local peer ID is never added to the PSM
-				// or added as a "known address", even if given.
-				if peer == self.local_peer_id {
-					Err("Local peer ID in priority group.".to_string())
-				} else {
-					Ok((peer, addr))
-				}
-			})
-			.collect::<Result<Vec<(PeerId, Multiaddr)>, String>>()?;
 
 		let peer_ids = peers.iter().map(|(peer_id, _addr)| peer_id.clone()).collect();
 
@@ -1004,6 +988,47 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkService<B, H> {
 		Ok(())
 	}
 
+	/// Add peers to a peerset priority group.
+	///
+	/// Each `Multiaddr` must end with a `/p2p/` component containing the `PeerId`.
+	///
+	/// Returns an `Err` if one of the given addresses is invalid or contains an
+	/// invalid peer ID (which includes the local peer ID).
+	//
+	// NOTE: even though this function is currently sync, it's marked as async for
+	// future-proofing, see https://github.com/paritytech/substrate/pull/7247#discussion_r502263451.
+	pub async fn add_to_priority_group(&self, group_id: String, peers: HashSet<Multiaddr>) -> Result<(), String> {
+		let peers = self.split_multiaddr_and_peer_id(peers)?;
+
+		for (peer_id, addr) in peers.into_iter() {
+			self.peerset.add_to_priority_group(group_id.clone(), peer_id.clone());
+
+			let _ = self
+				.to_worker
+				.unbounded_send(ServiceToWorkerMsg::AddKnownAddress(peer_id, addr));
+		}
+
+		Ok(())
+	}
+
+	/// Remove peers from a peerset priority group.
+	///
+	/// Each `Multiaddr` must end with a `/p2p/` component containing the `PeerId`.
+	///
+	/// Returns an `Err` if one of the given addresses is invalid or contains an
+	/// invalid peer ID (which includes the local peer ID).
+	//
+	// NOTE: even though this function is currently sync, it's marked as async for
+	// future-proofing, see https://github.com/paritytech/substrate/pull/7247#discussion_r502263451.
+	// NOTE: technically, this function only needs `Vec<PeerId>`, but we use `Multiaddr` here for convenience.
+	pub async fn remove_from_priority_group(&self, group_id: String, peers: HashSet<Multiaddr>) -> Result<(), String> {
+		let peers = self.split_multiaddr_and_peer_id(peers)?;
+		for (peer_id, _) in peers.into_iter() {
+			self.peerset.remove_from_priority_group(group_id.clone(), peer_id);
+		}
+		Ok(())
+	}
+
 	/// Returns the number of peers we're connected to.
 	pub fn num_connected(&self) -> usize {
 		self.num_connected.load(Ordering::Relaxed)
@@ -1025,6 +1050,30 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkService<B, H> {
 			.to_worker
 			.unbounded_send(ServiceToWorkerMsg::OwnBlockImported(hash, number));
 	}
+
+	/// Utility function to extract `PeerId` from each `Multiaddr` for priority group updates.
+	///
+	/// Returns an `Err` if one of the given addresses is invalid or contains an
+	/// invalid peer ID (which includes the local peer ID).
+	fn split_multiaddr_and_peer_id(&self, peers: HashSet<Multiaddr>) -> Result<Vec<(PeerId, Multiaddr)>, String> {
+		peers.into_iter()
+			.map(|mut addr| {
+				let peer = match addr.pop() {
+					Some(multiaddr::Protocol::P2p(key)) => PeerId::from_multihash(key)
+						.map_err(|_| "Invalid PeerId format".to_string())?,
+					_ => return Err("Missing PeerId from address".to_string()),
+				};
+
+				// Make sure the local peer ID is never added to the PSM
+				// or added as a "known address", even if given.
+				if peer == self.local_peer_id {
+					Err("Local peer ID in priority group.".to_string())
+				} else {
+					Ok((peer, addr))
+				}
+			})
+			.collect::<Result<Vec<(PeerId, Multiaddr)>, String>>()
+	}
 }
 
 impl<B: BlockT + 'static, H: ExHashT> sp_consensus::SyncOracle