fix race by sending signal instead of stopping pongTimer

p2p/conn/connection.go

@@ -89,7 +89,7 @@ type MConnection struct {
 
 	// close conn if pong is not received in pongTimeout
 	pongTimer     *time.Timer
-	pongTimeoutCh chan struct{}
+	pongTimeoutCh chan bool // true - timeout, false - peer sent pong
 
 	chStatsTimer *cmn.RepeatTimer // update channel stats periodically
 
@@ -191,7 +191,7 @@ func (c *MConnection) OnStart() error {
 	c.quit = make(chan struct{})
 	c.flushTimer = cmn.NewThrottleTimer("flush", c.config.FlushThrottle)
 	c.pingTimer = cmn.NewRepeatTimer("ping", c.config.PingInterval)
-	c.pongTimeoutCh = make(chan struct{})
+	c.pongTimeoutCh = make(chan bool)
 	c.chStatsTimer = cmn.NewRepeatTimer("chStats", updateStats)
 	go c.sendRoutine()
 	go c.recvRoutine()
@@ -339,19 +339,22 @@ FOR_LOOP:
 			c.sendMonitor.Update(int(n))
 			c.Logger.Debug("Starting pong timer", "dur", c.config.PongTimeout)
 			c.pongTimer = time.AfterFunc(c.config.PongTimeout, func() {
-				c.pongTimeoutCh <- struct{}{}
+				c.pongTimeoutCh <- true
 			})
 			c.flush()
-		case <-c.pongTimeoutCh:
-			c.Logger.Debug("Pong timeout")
-			err = errors.New("pong timeout")
+		case timeout := <-c.pongTimeoutCh:
+			if timeout {
+				c.Logger.Debug("Pong timeout")
+				err = errors.New("pong timeout")
+			} else {
+				c.stopPongTimer()
+			}
 		case <-c.pong:
 			c.Logger.Debug("Send Pong")
 			wire.WriteByte(packetTypePong, c.bufWriter, &n, &err)
 			c.sendMonitor.Update(int(n))
 			c.flush()
 		case <-c.quit:
-			c.stopPongTimer()
 			break FOR_LOOP
 		case <-c.send:
 			// Send some msgPackets
@@ -376,6 +379,7 @@ FOR_LOOP:
 	}
 
 	// Cleanup
+	c.stopPongTimer()
 }
 
 // Returns true if messages from channels were exhausted.
@@ -486,7 +490,11 @@ FOR_LOOP:
 			}
 		case packetTypePong:
 			c.Logger.Debug("Receive Pong")
-			c.stopPongTimer()
+			select {
+			case c.pongTimeoutCh <- false:
+			case <-c.quit:
+				break FOR_LOOP
+			}
 		case packetTypeMsg:
 			pkt, n, err := msgPacket{}, int(0), error(nil)
 			wire.ReadBinaryPtr(&pkt, c.bufReader, c.config.maxMsgPacketTotalSize(), &n, &err)
@@ -534,12 +542,14 @@ FOR_LOOP:
 	}
 }
 
+// not goroutine-safe
 func (c *MConnection) stopPongTimer() {
 	if c.pongTimer != nil {
 		if !c.pongTimer.Stop() {
 			<-c.pongTimer.C
 		}
 		drain(c.pongTimeoutCh)
+		c.pongTimer = nil
 	}
 }
 
@@ -771,7 +781,7 @@ func (p msgPacket) String() string {
 	return fmt.Sprintf("MsgPacket{%X:%X T:%X}", p.ChannelID, p.Bytes, p.EOF)
 }
 
-func drain(ch <-chan struct{}) {
+func drain(ch <-chan bool) {
 	for {
 		select {
 		case <-ch: