udp: replace concurrently reset timer with ticker

Co-authored-by: Julien Salleyron <julien.salleyron@gmail.com>

integration/udp_test.go

@@ -101,7 +101,7 @@ func (s *UDPSuite) TestWRR(c *check.C) {
 
 	select {
 	case <-stop:
-	case <-time.Tick(time.Second * 5):
+	case <-time.Tick(5 * time.Second):
 		c.Error("Timeout")
 	}
 }

pkg/server/server_entrypoint_tcp_test.go

@@ -84,7 +84,7 @@ func testShutdown(t *testing.T, router *tcp.Router) {
 	request, err := http.NewRequest(http.MethodHead, "http://127.0.0.1:8082", nil)
 	require.NoError(t, err)
 
-	time.Sleep(time.Millisecond * 100)
+	time.Sleep(100 * time.Millisecond)
 
 	// We need to do a write on the conn before the shutdown to make it "exist".
 	// Because the connection indeed exists as far as TCP is concerned,
@@ -104,7 +104,7 @@ func testShutdown(t *testing.T, router *tcp.Router) {
 		loopConn, err := net.Dial("tcp", epAddr)
 		if err == nil {
 			loopConn.Close()
-			time.Sleep(time.Millisecond * 100)
+			time.Sleep(100 * time.Millisecond)
 			continue
 		}
 		if !strings.HasSuffix(err.Error(), "connection refused") && !strings.HasSuffix(err.Error(), "reset by peer") {
@@ -135,7 +135,7 @@ func startEntrypoint(entryPoint *TCPEntryPoint, router *tcp.Router) (net.Conn, e
 	for i := 0; i < 10; i++ {
 		conn, err = net.Dial("tcp", entryPoint.listener.Addr().String())
 		if err != nil {
-			time.Sleep(time.Millisecond * 100)
+			time.Sleep(100 * time.Millisecond)
 			continue
 		}
 		epStarted = true
@@ -150,7 +150,7 @@ func startEntrypoint(entryPoint *TCPEntryPoint, router *tcp.Router) (net.Conn, e
 func TestReadTimeoutWithoutFirstByte(t *testing.T) {
 	epConfig := &static.EntryPointsTransport{}
 	epConfig.SetDefaults()
-	epConfig.RespondingTimeouts.ReadTimeout = types.Duration(time.Second * 2)
+	epConfig.RespondingTimeouts.ReadTimeout = types.Duration(2 * time.Second)
 
 	entryPoint, err := NewTCPEntryPoint(context.Background(), &static.EntryPoint{
 		Address:          ":0",
@@ -178,7 +178,7 @@ func TestReadTimeoutWithoutFirstByte(t *testing.T) {
 	select {
 	case err := <-errChan:
 		require.Equal(t, io.EOF, err)
-	case <-time.Tick(time.Second * 5):
+	case <-time.Tick(5 * time.Second):
 		t.Error("Timeout while read")
 	}
 }
@@ -186,7 +186,7 @@ func TestReadTimeoutWithoutFirstByte(t *testing.T) {
 func TestReadTimeoutWithFirstByte(t *testing.T) {
 	epConfig := &static.EntryPointsTransport{}
 	epConfig.SetDefaults()
-	epConfig.RespondingTimeouts.ReadTimeout = types.Duration(time.Second * 2)
+	epConfig.RespondingTimeouts.ReadTimeout = types.Duration(2 * time.Second)
 
 	entryPoint, err := NewTCPEntryPoint(context.Background(), &static.EntryPoint{
 		Address:          ":0",
@@ -217,7 +217,7 @@ func TestReadTimeoutWithFirstByte(t *testing.T) {
 	select {
 	case err := <-errChan:
 		require.Equal(t, io.EOF, err)
-	case <-time.Tick(time.Second * 5):
+	case <-time.Tick(5 * time.Second):
 		t.Error("Timeout while read")
 	}
 }

pkg/server/server_entrypoint_udp_test.go

@@ -92,7 +92,7 @@ func TestShutdownUDPConn(t *testing.T) {
 
 	select {
 	case <-doneChan:
-	case <-time.Tick(time.Second * 5):
+	case <-time.Tick(10 * time.Second):
 		// In case we introduce a regression that would make the test wait forever.
 		t.Fatal("Timeout during shutdown")
 	}

pkg/udp/conn.go

@@ -14,7 +14,9 @@ const closeRetryInterval = 500 * time.Millisecond
 
 // connTimeout determines how long to wait on an idle session,
 // before releasing all resources related to that session.
-const connTimeout = time.Second * 3
+const connTimeout = 3 * time.Second
+
+var timeoutTicker = connTimeout / 10
 
 var errClosedListener = errors.New("udp: listener closed")
 
@@ -175,7 +177,7 @@ func (l *Listener) newConn(rAddr net.Addr) *Conn {
 		readCh:    make(chan []byte),
 		sizeCh:    make(chan int),
 		doneCh:    make(chan struct{}),
-		timer:     time.NewTimer(connTimeout),
+		ticker:    time.NewTicker(timeoutTicker),
 	}
 }
 
@@ -189,7 +191,10 @@ type Conn struct {
 	sizeCh    chan int    // to synchronize with the end of a Read
 	msgs      [][]byte    // to store data from listener, to be consumed by Reads
 
-	timer    *time.Timer // for timeouts
+	muActivity   sync.RWMutex
+	lastActivity time.Time // the last time the session saw either read or write activity
+
+	ticker   *time.Ticker // for timeouts
 	doneOnce sync.Once
 	doneCh   chan struct{}
 }
@@ -204,10 +209,16 @@ func (c *Conn) readLoop() {
 			select {
 			case msg := <-c.receiveCh:
 				c.msgs = append(c.msgs, msg)
-			case <-c.timer.C:
+			case <-c.ticker.C:
+				c.muActivity.RLock()
+				deadline := c.lastActivity.Add(connTimeout)
+				c.muActivity.RUnlock()
+				if time.Now().After(deadline) {
 					c.Close()
 					return
 				}
+				continue
+			}
 		}
 
 		select {
@@ -218,11 +229,16 @@ func (c *Conn) readLoop() {
 			c.sizeCh <- n
 		case msg := <-c.receiveCh:
 			c.msgs = append(c.msgs, msg)
-		case <-c.timer.C:
+		case <-c.ticker.C:
+			c.muActivity.RLock()
+			deadline := c.lastActivity.Add(connTimeout)
+			c.muActivity.RUnlock()
+			if time.Now().After(deadline) {
 				c.Close()
 				return
 			}
 		}
+	}
 }
 
 // Read implements io.Reader for a Conn.
@@ -230,7 +246,9 @@ func (c *Conn) Read(p []byte) (int, error) {
 	select {
 	case c.readCh <- p:
 		n := <-c.sizeCh
-		c.timer.Reset(connTimeout)
+		c.muActivity.Lock()
+		c.lastActivity = time.Now()
+		c.muActivity.Unlock()
 		return n, nil
 	case <-c.doneCh:
 		return 0, io.EOF
@@ -244,7 +262,9 @@ func (c *Conn) Write(p []byte) (n int, err error) {
 		return 0, io.EOF
 	}
 
-	c.timer.Reset(connTimeout)
+	c.muActivity.Lock()
+	c.lastActivity = time.Now()
+	c.muActivity.Unlock()
 	return l.pConn.WriteTo(p, c.rAddr)
 }
 
@@ -261,5 +281,6 @@ func (c *Conn) Close() error {
 	c.listener.mu.Lock()
 	defer c.listener.mu.Unlock()
 	delete(c.listener.conns, c.rAddr.String())
+	c.ticker.Stop()
 	return nil
 }

pkg/udp/conn_test.go

@@ -43,7 +43,7 @@ func TestListenNotBlocking(t *testing.T) {
 				require.NoError(t, err)
 
 				// This should not block second call
-				time.Sleep(time.Second * 10)
+				time.Sleep(10 * time.Second)
 			}()
 		}
 	}()
@@ -148,7 +148,7 @@ func testTimeout(t *testing.T, withRead bool) {
 
 	assert.Equal(t, 10, len(ln.conns))
 
-	time.Sleep(3 * time.Second)
+	time.Sleep(4 * time.Second)
 	assert.Equal(t, 0, len(ln.conns))
 }
 
@@ -239,7 +239,7 @@ func TestShutdown(t *testing.T) {
 
 	select {
 	case <-doneChan:
-	case <-time.Tick(time.Second * 5):
+	case <-time.Tick(5 * time.Second):
 		// In case we introduce a regression that would make the test wait forever.
 		t.Fatal("Timeout during shutdown")
 	}