maintain preferred peer connections (#3435)

p2p/src/peers.rs

@@ -416,7 +416,12 @@ impl Peers {
 	/// Iterate over the peer list and prune all peers we have
 	/// lost connection to or have been deemed problematic.
 	/// Also avoid connected peer count getting too high.
-	pub fn clean_peers(&self, max_inbound_count: usize, max_outbound_count: usize) {
+	pub fn clean_peers(
+		&self,
+		max_inbound_count: usize,
+		max_outbound_count: usize,
+		preferred_peers: &[PeerAddr],
+	) {
 		let mut rm = vec![];
 
 		// build a list of peers to be cleaned up
@@ -464,25 +469,27 @@ impl Peers {
 		let excess_outgoing_count =
 			(self.peer_outbound_count() as usize).saturating_sub(max_outbound_count);
 		if excess_outgoing_count > 0 {
-			let mut addrs = self
+			let mut addrs: Vec<_> = self
 				.outgoing_connected_peers()
 				.iter()
+				.filter(|x| !preferred_peers.contains(&x.info.addr))
 				.take(excess_outgoing_count)
 				.map(|x| x.info.addr)
-				.collect::<Vec<_>>();
+				.collect();
 			rm.append(&mut addrs);
 		}
 
 		// check here to make sure we don't have too many incoming connections
 		let excess_incoming_count =
 			(self.peer_inbound_count() as usize).saturating_sub(max_inbound_count);
 		if excess_incoming_count > 0 {
-			let mut addrs = self
+			let mut addrs: Vec<_> = self
 				.incoming_connected_peers()
 				.iter()
+				.filter(|x| !preferred_peers.contains(&x.info.addr))
 				.take(excess_incoming_count)
 				.map(|x| x.info.addr)
-				.collect::<Vec<_>>();
+				.collect();
 			rm.append(&mut addrs);
 		}
 

servers/src/grin/seed.rs

@@ -52,9 +52,11 @@ pub fn connect_and_monitor(
 	p2p_server: Arc<p2p::Server>,
 	capabilities: p2p::Capabilities,
 	seed_list: Box<dyn Fn() -> Vec<PeerAddr> + Send>,
-	preferred_peers: Option<Vec<PeerAddr>>,
+	preferred_peers: &[PeerAddr],
 	stop_state: Arc<StopState>,
 ) -> std::io::Result<thread::JoinHandle<()>> {
+	let preferred_peers = preferred_peers.to_vec();
+
 	thread::Builder::new()
 		.name("seed".to_string())
 		.spawn(move || {
@@ -69,7 +71,7 @@ pub fn connect_and_monitor(
 				peers.clone(),
 				tx.clone(),
 				seed_list,
-				preferred_peers.clone(),
+				&preferred_peers,
 			);
 
 			let mut prev = MIN_DATE.and_hms(0, 0, 0);
@@ -113,7 +115,7 @@ pub fn connect_and_monitor(
 						peers.clone(),
 						p2p_server.config.clone(),
 						tx.clone(),
-						preferred_peers.clone(),
+						&preferred_peers,
 					);
 
 					prev = Utc::now();
@@ -141,7 +143,7 @@ fn monitor_peers(
 	peers: Arc<p2p::Peers>,
 	config: p2p::P2PConfig,
 	tx: mpsc::Sender<PeerAddr>,
-	preferred_peers_list: Option<Vec<PeerAddr>>,
+	preferred_peers: &[PeerAddr],
 ) {
 	// regularly check if we need to acquire more peers  and if so, gets
 	// them from db
@@ -189,6 +191,7 @@ fn monitor_peers(
 	peers.clean_peers(
 		config.peer_max_inbound_count() as usize,
 		config.peer_max_outbound_count() as usize,
+		preferred_peers,
 	);
 
 	if peers.enough_outbound_peers() {
@@ -209,16 +212,14 @@ fn monitor_peers(
 		connected_peers.push(p.info.addr)
 	}
 
-	// Attempt to connect to preferred peers if there is some
-	if let Some(preferred_peers) = preferred_peers_list {
-		for p in preferred_peers {
-			if !connected_peers.is_empty() {
-				if !connected_peers.contains(&p) {
-					tx.send(p).unwrap();
-				}
-			} else {
-				tx.send(p).unwrap();
+	// Attempt to connect to any preferred peers.
+	for p in preferred_peers {
+		if !connected_peers.is_empty() {
+			if !connected_peers.contains(p) {
+				tx.send(*p).unwrap();
 			}
+		} else {
+			tx.send(*p).unwrap();
 		}
 	}
 
@@ -257,7 +258,7 @@ fn connect_to_seeds_and_preferred_peers(
 	peers: Arc<p2p::Peers>,
 	tx: mpsc::Sender<PeerAddr>,
 	seed_list: Box<dyn Fn() -> Vec<PeerAddr>>,
-	peers_preferred_list: Option<Vec<PeerAddr>>,
+	peers_preferred: &[PeerAddr],
 ) {
 	// check if we have some peers in db
 	// look for peers that are able to give us other peers (via PEER_LIST capability)
@@ -270,11 +271,8 @@ fn connect_to_seeds_and_preferred_peers(
 		seed_list()
 	};
 
-	// If we have preferred peers add them to the connection
-	match peers_preferred_list {
-		Some(mut peers_preferred) => peer_addrs.append(&mut peers_preferred),
-		None => trace!("No preferred peers"),
-	};
+	// If we have preferred peers add them to the initial list
+	peer_addrs.extend_from_slice(peers_preferred);
 
 	if peer_addrs.is_empty() {
 		warn!("No seeds were retrieved.");

servers/src/grin/server.rs

@@ -248,13 +248,16 @@ impl Server {
 				_ => unreachable!(),
 			};
 
-			let preferred_peers = config.p2p_config.peers_preferred.clone().map(|p| p.peers);
+			let preferred_peers = match &config.p2p_config.peers_preferred {
+				Some(addrs) => addrs.peers.clone(),
+				None => vec![],
+			};
 
 			connect_thread = Some(seed::connect_and_monitor(
 				p2p_server.clone(),
 				config.p2p_config.capabilities,
 				seeder,
-				preferred_peers,
+				&preferred_peers,
 				stop_state.clone(),
 			)?);
 		}