Resolve lock contention whenever bans occur with multiple clients connected

p2pool/p2p/client.go

@@ -978,20 +978,22 @@ func (c *Client) Close() bool {
 		c.Ban(DefaultBanTime, errors.New("disconnected before finishing handshake"))
 	}
 
-	c.Owner.clientsLock.Lock()
-	defer c.Owner.clientsLock.Unlock()
-	if c.Owner.fastestPeer == c {
-		c.Owner.fastestPeer = nil
-	}
-	if i := slices.Index(c.Owner.clients, c); i != -1 {
-		c.Owner.clients = slices.Delete(c.Owner.clients, i, i+1)
-		if c.IsIncomingConnection {
-			c.Owner.NumIncomingConnections.Add(-1)
-		} else {
-			c.Owner.NumOutgoingConnections.Add(-1)
-			c.Owner.PendingOutgoingConnections.Replace(c.AddressPort.Addr().String(), "")
+	func() {
+		c.Owner.clientsLock.Lock()
+		defer c.Owner.clientsLock.Unlock()
+		if c.Owner.fastestPeer == c {
+			c.Owner.fastestPeer = nil
 		}
-	}
+		if i := slices.Index(c.Owner.clients, c); i != -1 {
+			c.Owner.clients = slices.Delete(c.Owner.clients, i, i+1)
+			if c.IsIncomingConnection {
+				c.Owner.NumIncomingConnections.Add(-1)
+			} else {
+				c.Owner.NumOutgoingConnections.Add(-1)
+				c.Owner.PendingOutgoingConnections.Replace(c.AddressPort.Addr().String(), "")
+			}
+		}
+	}()
 
 	_ = c.Connection.Close()
 	close(c.closeChannel)

p2pool/p2p/server.go

@@ -273,6 +273,19 @@ func (s *Server) UpdatePeerList() {
 	}
 }
 
+func (s *Server) CleanupBanList() {
+	s.bansLock.Lock()
+	defer s.bansLock.Unlock()
+
+	currentTime := uint64(time.Now().Unix())
+
+	for k, b := range s.bans {
+		if currentTime >= b.Expiration {
+			delete(s.bans, k)
+		}
+	}
+}
+
 func (s *Server) UpdateClientConnections() {
 
 	currentTime := uint64(time.Now().Unix())
@@ -495,6 +508,14 @@ func (s *Server) Listen() (err error) {
 				s.RefreshOutgoingIPv6()
 			}
 		}()
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for range utils.ContextTick(s.ctx, time.Minute*5) {
+				s.CleanupBanList()
+			}
+		}()
+
 		for !s.close.Load() {
 			if conn, err := s.listener.AcceptTCP(); err != nil {
 				return err
@@ -675,18 +696,14 @@ func (s *Server) IsBanned(ip netip.Addr) (bool, *BanEntry) {
 
 	k := prefix.Addr().As16()
 
-	s.bansLock.RLock()
-	defer s.bansLock.RUnlock()
-
-	if b, ok := s.bans[k]; ok == false {
+	if b, ok := func() (entry BanEntry, ok bool) {
+		s.bansLock.RLock()
+		defer s.bansLock.RUnlock()
+		entry, ok = s.bans[k]
+		return entry, ok
+	}(); ok == false {
 		return false, nil
 	} else if uint64(time.Now().Unix()) >= b.Expiration {
-		go func() {
-			//HACK: delay via goroutine
-			s.bansLock.Lock()
-			defer s.bansLock.Unlock()
-			delete(s.bans, k)
-		}()
 		return false, nil
 	} else {
 		return true, &b
@@ -697,32 +714,34 @@ func (s *Server) Ban(ip netip.Addr, duration time.Duration, err error) {
 	if ok, _ := s.IsBanned(ip); ok {
 		return
 	}
-	go func() {
-		log.Printf("[P2PServer] Banned %s for %s: %s", ip.String(), duration.String(), err.Error())
-		if !ip.IsLoopback() {
-			ip = ip.Unmap()
-			var prefix netip.Prefix
-			if ip.Is6() {
-				//ban the /64
-				prefix, _ = ip.Prefix(64)
-			} else if ip.Is4() {
-				//ban only a single ip, /32
-				prefix, _ = ip.Prefix(32)
-			}
 
-			if prefix.IsValid() {
+	log.Printf("[P2PServer] Banned %s for %s: %s", ip.String(), duration.String(), err.Error())
+	if !ip.IsLoopback() {
+		ip = ip.Unmap()
+		var prefix netip.Prefix
+		if ip.Is6() {
+			//ban the /64
+			prefix, _ = ip.Prefix(64)
+		} else if ip.Is4() {
+			//ban only a single ip, /32
+			prefix, _ = ip.Prefix(32)
+		}
+
+		if prefix.IsValid() {
+			func() {
 				s.bansLock.Lock()
 				defer s.bansLock.Unlock()
 				s.bans[prefix.Addr().As16()] = BanEntry{
 					Error:      err,
 					Expiration: uint64(time.Now().Unix()) + uint64(duration.Seconds()),
 				}
-				for _, c := range s.GetAddressConnectedPrefix(prefix) {
-					c.Close()
-				}
+			}()
+			for _, c := range s.GetAddressConnectedPrefix(prefix) {
+				c.Close()
 			}
 		}
-	}()
+	}
+
 }
 
 func (s *Server) Close() {