don't send path MTU probe packets on a timer

quic-go · May 22, 2022 · fdc5227 · fdc5227
1 parent fa0dba9
commit fdc5227
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Showing 5 changed files with 2 additions and 39 deletions.
diff --git a/connection.go b/connection.go
@@ -751,11 +751,6 @@ func (s *connection) maybeResetTimer() {
 			deadline = s.idleTimeoutStartTime().Add(s.idleTimeout)
 		}
 	}
-	if s.handshakeConfirmed && !s.config.DisablePathMTUDiscovery {
-		if probeTime := s.mtuDiscoverer.NextProbeTime(); !probeTime.IsZero() {
-			deadline = utils.MinTime(deadline, probeTime)
-		}
-	}
 
 	if ackAlarm := s.receivedPacketHandler.GetAlarmTimeout(); !ackAlarm.IsZero() {
 		deadline = utils.MinTime(deadline, ackAlarm)

diff --git a/connection_test.go b/connection_test.go
@@ -1692,11 +1692,7 @@ var _ = Describe("Connection", func() {
 			written := make(chan struct{}, 1)
 			sender.EXPECT().WouldBlock().AnyTimes()
 			sender.EXPECT().Send(gomock.Any()).DoAndReturn(func(p *packetBuffer) { written <- struct{}{} })
-			gomock.InOrder(
-				mtuDiscoverer.EXPECT().NextProbeTime(),
-				mtuDiscoverer.EXPECT().ShouldSendProbe(gomock.Any()).Return(true),
-				mtuDiscoverer.EXPECT().NextProbeTime(),
-			)
+			mtuDiscoverer.EXPECT().ShouldSendProbe(gomock.Any()).Return(true)
 			ping := ackhandler.Frame{Frame: &wire.PingFrame{}}
 			mtuDiscoverer.EXPECT().GetPing().Return(ping, protocol.ByteCount(1234))
 			packer.EXPECT().PackMTUProbePacket(ping, protocol.ByteCount(1234)).Return(getPacket(1), nil)

diff --git a/mock_mtu_discoverer_test.go b/mock_mtu_discoverer_test.go
diff --git a/mtu_discoverer.go b/mtu_discoverer.go
@@ -11,7 +11,6 @@ import (
 
 type mtuDiscoverer interface {
 	ShouldSendProbe(now time.Time) bool
-	NextProbeTime() time.Time
 	GetPing() (ping ackhandler.Frame, datagramSize protocol.ByteCount)
 }
 
@@ -53,16 +52,7 @@ func (f *mtuFinder) ShouldSendProbe(now time.Time) bool {
 	if f.probeInFlight || f.done() {
 		return false
 	}
-	return !now.Before(f.NextProbeTime())
-}
-
-// NextProbeTime returns the time when the next probe packet should be sent.
-// It returns the zero value if no probe packet should be sent.
-func (f *mtuFinder) NextProbeTime() time.Time {
-	if f.probeInFlight || f.done() {
-		return time.Time{}
-	}
-	return f.lastProbeTime.Add(mtuProbeDelay * f.rttStats.SmoothedRTT())
+	return !now.Before(f.lastProbeTime.Add(mtuProbeDelay * f.rttStats.SmoothedRTT()))
 }
 
 func (f *mtuFinder) GetPing() (ackhandler.Frame, protocol.ByteCount) {

diff --git a/mtu_discoverer_test.go b/mtu_discoverer_test.go
@@ -38,17 +38,14 @@ var _ = Describe("MTU Discoverer", func() {
 	It("only allows a probe 5 RTTs after the handshake completes", func() {
 		Expect(d.ShouldSendProbe(now)).To(BeFalse())
 		Expect(d.ShouldSendProbe(now.Add(rtt * 9 / 2))).To(BeFalse())
-		Expect(d.NextProbeTime()).To(BeTemporally("~", now.Add(5*rtt), scaleDuration(20*time.Millisecond)))
 		Expect(d.ShouldSendProbe(now.Add(rtt * 5))).To(BeTrue())
 	})
 
 	It("doesn't allow a probe if another probe is still in flight", func() {
 		ping, _ := d.GetPing()
 		Expect(d.ShouldSendProbe(now.Add(10 * rtt))).To(BeFalse())
-		Expect(d.NextProbeTime()).To(BeZero())
 		ping.OnLost(ping.Frame)
 		Expect(d.ShouldSendProbe(now.Add(10 * rtt))).To(BeTrue())
-		Expect(d.NextProbeTime()).ToNot(BeZero())
 	})
 
 	It("tries a lower size when a probe is lost", func() {
@@ -79,7 +76,6 @@ var _ = Describe("MTU Discoverer", func() {
 		}
 		Expect(sizes).To(Equal([]protocol.ByteCount{1500, 1750, 1875, 1937, 1968, 1984}))
 		Expect(d.ShouldSendProbe(t.Add(10 * rtt))).To(BeFalse())
-		Expect(d.NextProbeTime()).To(BeZero())
 	})
 
 	It("finds the MTU", func() {