From 80f3ec2312a1996e2871c5bef1ef13cb8742e166 Mon Sep 17 00:00:00 2001
From: Roman Khimov <roman@nspcc.ru>
Date: Fri, 6 Aug 2021 15:04:13 +0300
Subject: [PATCH] network: move peer filtering to getPeers()

It doesn't change much, we can't magically get more valid peers and if some
die while we're iterating we'd detect that by an error returned from send().
---
 pkg/network/server.go | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/pkg/network/server.go b/pkg/network/server.go
index a4311a521..2818d5de7 100644
--- a/pkg/network/server.go
+++ b/pkg/network/server.go
@@ -288,7 +288,7 @@ func (s *Server) Shutdown() {
 	s.transport.Close()
 	s.discovery.Close()
 	s.consensus.Shutdown()
-	for _, p := range s.getPeers() {
+	for _, p := range s.getPeers(nil) {
 		p.Disconnect(errServerShutdown)
 	}
 	s.bQueue.discard()
@@ -431,7 +431,7 @@ func (s *Server) runProto() {
 		case <-pingTimer.C:
 			if s.chain.BlockHeight() == prevHeight {
 				// Get a copy of s.peers to avoid holding a lock while sending.
-				for _, peer := range s.getPeers() {
+				for _, peer := range s.getPeers(nil) {
 					_ = peer.SendPing(NewMessage(CMDPing, payload.NewPing(s.chain.BlockHeight(), s.id)))
 				}
 			}
@@ -489,14 +489,17 @@ func (s *Server) UnsubscribeFromNotaryRequests(ch chan<- mempoolevent.Event) {
 	s.notaryRequestPool.UnsubscribeFromTransactions(ch)
 }
 
-// getPeers returns current list of peers connected to
-// the server.
-func (s *Server) getPeers() []Peer {
+// getPeers returns current list of peers connected to the server filtered by
+// isOK function if it's given.
+func (s *Server) getPeers(isOK func(Peer) bool) []Peer {
 	s.lock.RLock()
 	defer s.lock.RUnlock()
 
 	peers := make([]Peer, 0, len(s.peers))
 	for k := range s.peers {
+		if isOK != nil && !isOK(k) {
+			continue
+		}
 		peers = append(peers, k)
 	}
 
@@ -1142,7 +1145,7 @@ func (s *Server) requestTx(hashes ...util.Uint256) {
 // peer is considered invalid if it returns false).
 func (s *Server) iteratePeersWithSendMsg(msg *Message, send func(Peer, bool, []byte) error, peerOK func(Peer) bool) {
 	// Get a copy of s.peers to avoid holding a lock while sending.
-	peers := s.getPeers()
+	peers := s.getPeers(peerOK)
 	if len(peers) == 0 {
 		return
 	}
@@ -1158,9 +1161,6 @@ func (s *Server) iteratePeersWithSendMsg(msg *Message, send func(Peer, bool, []b
 	okCount := 0
 	sentCount := 0
 	for i, peer := range peers {
-		if peerOK != nil && !peerOK(peer) {
-			continue
-		}
 		okCount++
 		if err := send(peer, false, pkt); err != nil {
 			continue
@@ -1179,7 +1179,7 @@ func (s *Server) iteratePeersWithSendMsg(msg *Message, send func(Peer, bool, []b
 
 	// Perform blocking send now.
 	for i, peer := range peers {
-		if success[i] || (peerOK != nil && !peerOK(peer)) {
+		if success[i] {
 			continue
 		}
 		if err := send(peer, true, pkt); err != nil {