derp: use tstime (#8634)

Updates #8587

Signed-off-by: Claire Wang <claire@tailscale.com>

cmd/derper/depaware.txt

@@ -115,6 +115,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         tailscale.com/tailcfg                                        from tailscale.com/client/tailscale+
         tailscale.com/tka                                            from tailscale.com/client/tailscale+
    W    tailscale.com/tsconst                                        from tailscale.com/net/interfaces
+        tailscale.com/tstime                                         from tailscale.com/derp+
      💣 tailscale.com/tstime/mono                                    from tailscale.com/tstime/rate
         tailscale.com/tstime/rate                                    from tailscale.com/wgengine/filter+
         tailscale.com/tsweb                                          from tailscale.com/cmd/derper

cmd/tailscale/depaware.txt

@@ -108,6 +108,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         tailscale.com/tailcfg                                        from tailscale.com/cmd/tailscale/cli+
         tailscale.com/tka                                            from tailscale.com/client/tailscale+
    W    tailscale.com/tsconst                                        from tailscale.com/net/interfaces
+        tailscale.com/tstime                                         from tailscale.com/derp+
      💣 tailscale.com/tstime/mono                                    from tailscale.com/tstime/rate
         tailscale.com/tstime/rate                                    from tailscale.com/wgengine/filter+
         tailscale.com/types/dnstype                                  from tailscale.com/tailcfg

derp/derp_client.go

@@ -17,6 +17,7 @@
 	"go4.org/mem"
 	"golang.org/x/time/rate"
 	"tailscale.com/syncs"
+	"tailscale.com/tstime"
 	"tailscale.com/types/key"
 	"tailscale.com/types/logger"
 )
@@ -40,6 +41,8 @@ type Client struct {
 	// Owned by Recv:
 	peeked  int                      // bytes to discard on next Recv
 	readErr syncs.AtomicValue[error] // sticky (set by Recv)
+
+	clock tstime.Clock
 }
 
 // ClientOpt is an option passed to NewClient.
@@ -103,6 +106,7 @@ func newClient(privateKey key.NodePrivate, nc Conn, brw *bufio.ReadWriter, logf
 		meshKey:     opt.MeshKey,
 		canAckPings: opt.CanAckPings,
 		isProber:    opt.IsProber,
+		clock:       tstime.StdClock{},
 	}
 	if opt.ServerPub.IsZero() {
 		if err := c.recvServerKey(); err != nil {
@@ -214,7 +218,7 @@ func (c *Client) send(dstKey key.NodePublic, pkt []byte) (ret error) {
 	defer c.wmu.Unlock()
 	if c.rate != nil {
 		pktLen := frameHeaderLen + key.NodePublicRawLen + len(pkt)
-		if !c.rate.AllowN(time.Now(), pktLen) {
+		if !c.rate.AllowN(c.clock.Now(), pktLen) {
 			return nil // drop
 		}
 	}
@@ -244,7 +248,7 @@ func (c *Client) ForwardPacket(srcKey, dstKey key.NodePublic, pkt []byte) (err e
 	c.wmu.Lock()
 	defer c.wmu.Unlock()
 
-	timer := time.AfterFunc(5*time.Second, c.writeTimeoutFired)
+	timer := c.clock.AfterFunc(5*time.Second, c.writeTimeoutFired)
 	defer timer.Stop()
 
 	if err := writeFrameHeader(c.bw, frameForwardPacket, uint32(keyLen*2+len(pkt))); err != nil {
@@ -457,7 +461,6 @@ func (c *Client) recvTimeout(timeout time.Duration) (m ReceivedMessage, err erro
 			c.readErr.Store(err)
 		}
 	}()
-
 	for {
 		c.nc.SetReadDeadline(time.Now().Add(timeout))
 

derp/derp_server.go

@@ -39,6 +39,7 @@
 	"tailscale.com/envknob"
 	"tailscale.com/metrics"
 	"tailscale.com/syncs"
+	"tailscale.com/tstime"
 	"tailscale.com/tstime/rate"
 	"tailscale.com/types/key"
 	"tailscale.com/types/logger"
@@ -164,6 +165,8 @@ type Server struct {
 
 	// maps from netip.AddrPort to a client's public key
 	keyOfAddr map[netip.AddrPort]key.NodePublic
+
+	clock tstime.Clock
 }
 
 // clientSet represents 1 or more *sclients.
@@ -318,6 +321,7 @@ func NewServer(privateKey key.NodePrivate, logf logger.Logf) *Server {
 		avgQueueDuration:     new(uint64),
 		tcpRtt:               metrics.LabelMap{Label: "le"},
 		keyOfAddr:            map[netip.AddrPort]key.NodePublic{},
+		clock:                tstime.StdClock{},
 	}
 	s.initMetacert()
 	s.packetsRecvDisco = s.packetsRecvByKind.Get("disco")
@@ -467,8 +471,8 @@ func (s *Server) initMetacert() {
 			CommonName: fmt.Sprintf("derpkey%s", s.publicKey.UntypedHexString()),
 		},
 		// Windows requires NotAfter and NotBefore set:
-		NotAfter:  time.Now().Add(30 * 24 * time.Hour),
+		NotAfter:  s.clock.Now().Add(30 * 24 * time.Hour),
-		NotBefore: time.Now().Add(-30 * 24 * time.Hour),
+		NotBefore: s.clock.Now().Add(-30 * 24 * time.Hour),
 		// Per https://github.com/golang/go/issues/51759#issuecomment-1071147836,
 		// macOS requires BasicConstraints when subject == issuer:
 		BasicConstraintsValid: true,
@@ -697,7 +701,7 @@ func (s *Server) accept(ctx context.Context, nc Conn, brw *bufio.ReadWriter, rem
 		done:           ctx.Done(),
 		remoteAddr:     remoteAddr,
 		remoteIPPort:   remoteIPPort,
-		connectedAt:    time.Now(),
+		connectedAt:    s.clock.Now(),
 		sendQueue:      make(chan pkt, perClientSendQueueDepth),
 		discoSendQueue: make(chan pkt, perClientSendQueueDepth),
 		sendPongCh:     make(chan [8]byte, 1),
@@ -927,7 +931,7 @@ func (c *sclient) handleFrameForwardPacket(ft frameType, fl uint32) error {
 
 	return c.sendPkt(dst, pkt{
 		bs:         contents,
-		enqueuedAt: time.Now(),
+		enqueuedAt: c.s.clock.Now(),
 		src:        srcKey,
 	})
 }
@@ -994,7 +998,7 @@ func (c *sclient) handleFrameSendPacket(ft frameType, fl uint32) error {
 
 	p := pkt{
 		bs:         contents,
-		enqueuedAt: time.Now(),
+		enqueuedAt: c.s.clock.Now(),
 		src:        c.key,
 	}
 	return c.sendPkt(dst, p)
@@ -1387,7 +1391,7 @@ func (c *sclient) setPreferred(v bool) {
 	// graphs, so not important to miss a move. But it shouldn't:
 	// the netcheck/re-STUNs in magicsock only happen about every
 	// 30 seconds.
-	if time.Since(c.connectedAt) > 5*time.Second {
+	if c.s.clock.Since(c.connectedAt) > 5*time.Second {
 		homeMove.Add(1)
 	}
 }
@@ -1401,7 +1405,7 @@ func expMovingAverage(prev, newValue, alpha float64) float64 {
 
 // recordQueueTime updates the average queue duration metric after a packet has been sent.
 func (c *sclient) recordQueueTime(enqueuedAt time.Time) {
-	elapsed := float64(time.Since(enqueuedAt).Milliseconds())
+	elapsed := float64(c.s.clock.Since(enqueuedAt).Milliseconds())
 	for {
 		old := atomic.LoadUint64(c.s.avgQueueDuration)
 		newAvg := expMovingAverage(math.Float64frombits(old), elapsed, 0.1)
@@ -1431,7 +1435,7 @@ func (c *sclient) sendLoop(ctx context.Context) error {
 	}()
 
 	jitter := time.Duration(rand.Intn(5000)) * time.Millisecond
-	keepAliveTick := time.NewTicker(keepAlive + jitter)
+	keepAliveTick, keepAliveTickChannel := c.s.clock.NewTicker(keepAlive + jitter)
 	defer keepAliveTick.Stop()
 
 	var werr error // last write error
@@ -1461,7 +1465,7 @@ func (c *sclient) sendLoop(ctx context.Context) error {
 		case msg := <-c.sendPongCh:
 			werr = c.sendPong(msg)
 			continue
-		case <-keepAliveTick.C:
+		case <-keepAliveTickChannel:
 			werr = c.sendKeepAlive()
 			continue
 		default:
@@ -1490,7 +1494,7 @@ func (c *sclient) sendLoop(ctx context.Context) error {
 		case msg := <-c.sendPongCh:
 			werr = c.sendPong(msg)
 			continue
-		case <-keepAliveTick.C:
+		case <-keepAliveTickChannel:
 			werr = c.sendKeepAlive()
 		}
 	}

derp/derp_server_linux.go

@@ -27,13 +27,13 @@ func (c *sclient) statsLoop(ctx context.Context) error {
 
 	const statsInterval = 10 * time.Second
 
-	ticker := time.NewTicker(statsInterval)
+	ticker, tickerChannel := c.s.clock.NewTicker(statsInterval)
 	defer ticker.Stop()
 
 statsLoop:
 	for {
 		select {
-		case <-ticker.C:
+		case <-tickerChannel:
 			rtt, err := tcpinfo.RTT(conn)
 			if err != nil {
 				continue statsLoop

derp/derp_test.go

@@ -27,6 +27,7 @@
 	"golang.org/x/time/rate"
 	"tailscale.com/disco"
 	"tailscale.com/net/memnet"
+	"tailscale.com/tstest"
 	"tailscale.com/types/key"
 	"tailscale.com/types/logger"
 )
@@ -990,9 +991,10 @@ func TestClientRecv(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			c := &Client{
-				nc:   dummyNetConn{},
+				nc:    dummyNetConn{},
-				br:   bufio.NewReader(bytes.NewReader(tt.input)),
+				br:    bufio.NewReader(bytes.NewReader(tt.input)),
-				logf: t.Logf,
+				logf:  t.Logf,
+				clock: &tstest.Clock{},
 			}
 			got, err := c.Recv()
 			if err != nil {
@@ -1435,7 +1437,8 @@ func (w *countWriter) ResetStats() {
 func TestClientSendRateLimiting(t *testing.T) {
 	cw := new(countWriter)
 	c := &Client{
-		bw: bufio.NewWriter(cw),
+		bw:    bufio.NewWriter(cw),
+		clock: &tstest.Clock{},
 	}
 	c.setSendRateLimiter(ServerInfoMessage{})
 

derp/derphttp/derphttp_client.go

@@ -38,6 +38,7 @@
 	"tailscale.com/net/tshttpproxy"
 	"tailscale.com/syncs"
 	"tailscale.com/tailcfg"
+	"tailscale.com/tstime"
 	"tailscale.com/types/key"
 	"tailscale.com/types/logger"
 	"tailscale.com/util/cmpx"
@@ -83,6 +84,7 @@ type Client struct {
 	serverPubKey key.NodePublic
 	tlsState     *tls.ConnectionState
 	pingOut      map[derp.PingMessage]chan<- bool // chan to send to on pong
+	clock        tstime.Clock
 }
 
 func (c *Client) String() string {
@@ -101,6 +103,7 @@ func NewRegionClient(privateKey key.NodePrivate, logf logger.Logf, netMon *netmo
 		getRegion:  getRegion,
 		ctx:        ctx,
 		cancelCtx:  cancel,
+		clock:      tstime.StdClock{},
 	}
 	return c
 }
@@ -108,7 +111,7 @@ func NewRegionClient(privateKey key.NodePrivate, logf logger.Logf, netMon *netmo
 // NewNetcheckClient returns a Client that's only able to have its DialRegionTLS method called.
 // It's used by the netcheck package.
 func NewNetcheckClient(logf logger.Logf) *Client {
-	return &Client{logf: logf}
+	return &Client{logf: logf, clock: tstime.StdClock{}}
 }
 
 // NewClient returns a new DERP-over-HTTP client. It connects lazily.
@@ -129,6 +132,7 @@ func NewClient(privateKey key.NodePrivate, serverURL string, logf logger.Logf) (
 		url:        u,
 		ctx:        ctx,
 		cancelCtx:  cancel,
+		clock:      tstime.StdClock{},
 	}
 	return c, nil
 }
@@ -644,14 +648,14 @@ type res struct {
 		nwait++
 		go func() {
 			if proto == "tcp4" && c.preferIPv6() {
-				t := time.NewTimer(200 * time.Millisecond)
+				t, tChannel := c.clock.NewTimer(200 * time.Millisecond)
 				select {
 				case <-ctx.Done():
 					// Either user canceled original context,
 					// it timed out, or the v6 dial succeeded.
 					t.Stop()
 					return
-				case <-t.C:
+				case <-tChannel:
 					// Start v4 dial
 				}
 			}

derp/derphttp/mesh_client.go

@@ -51,7 +51,7 @@ func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key
 		present = map[key.NodePublic]bool{}
 	}
 	lastConnGen := 0
-	lastStatus := time.Now()
+	lastStatus := c.clock.Now()
 	logConnectedLocked := func() {
 		if loggedConnected {
 			return
@@ -61,7 +61,7 @@ func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key
 	}
 
 	const logConnectedDelay = 200 * time.Millisecond
-	timer := time.AfterFunc(2*time.Second, func() {
+	timer := c.clock.AfterFunc(2*time.Second, func() {
 		mu.Lock()
 		defer mu.Unlock()
 		logConnectedLocked()
@@ -91,11 +91,11 @@ func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key
 	}
 
 	sleep := func(d time.Duration) {
-		t := time.NewTimer(d)
+		t, tChannel := c.clock.NewTimer(d)
 		select {
 		case <-ctx.Done():
 			t.Stop()
-		case <-t.C:
+		case <-tChannel:
 		}
 	}
 
@@ -142,7 +142,7 @@ func (c *Client) RunWatchConnectionLoop(ctx context.Context, ignoreServerKey key
 			default:
 				continue
 			}
-			if now := time.Now(); now.Sub(lastStatus) > statusInterval {
+			if now := c.clock.Now(); now.Sub(lastStatus) > statusInterval {
 				lastStatus = now
 				infoLogf("%d peers", len(present))
 			}