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fix and optimize RTO computation

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fixes #144
This commit is contained in:
Lucas Clemente
2016-05-25 12:34:54 +02:00
parent d4a189b2d1
commit 9e0d211f5e
3 changed files with 40 additions and 48 deletions
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1
ackhandler/packet.go
View File

@@ -19,7 +19,6 @@ type Packet struct {
Retransmitted bool // has this Packet ever been retransmitted
sendTime time.Time
rtoTime time.Time
}
// GetStreamFramesForRetransmission gets all the streamframes for retransmission

48
ackhandler/sent_packet_handler.go
View File

@@ -19,7 +19,7 @@ var (
// ErrMapAccess occurs when a NACK contains invalid NACK ranges
ErrMapAccess = qerr.Error(qerr.InvalidAckData, "Packet does not exist in PacketHistory")
// ErrTooManyTrackedSentPackets occurs when the sentPacketHandler has to keep track of too many packets
ErrTooManyTrackedSentPackets = errors.New("To many outstanding not-acked and not retransmitted packets.")
ErrTooManyTrackedSentPackets = errors.New("Too many outstanding non-acked and non-retransmitted packets")
errAckForUnsentPacket = qerr.Error(qerr.InvalidAckData, "Received ACK for an unsent package")
)
@@ -31,6 +31,7 @@ var (
type sentPacketHandler struct {
lastSentPacketNumber protocol.PacketNumber
lastSentPacketEntropy EntropyAccumulator
lastSentPacketTime time.Time
highestInOrderAckedPacketNumber protocol.PacketNumber
LargestObserved protocol.PacketNumber
LargestObservedEntropy EntropyAccumulator
@@ -118,8 +119,8 @@ func (h *sentPacketHandler) SentPacket(packet *Packet) error {
return errWrongPacketNumberIncrement
}
now := time.Now()
h.lastSentPacketTime = now
packet.sendTime = now
packet.rtoTime = now.Add(h.getRTO())
if packet.Length == 0 {
return errors.New("SentPacketHandler: packet cannot be empty")
}
@@ -250,7 +251,7 @@ func (h *sentPacketHandler) ReceivedAck(ackFrame *frames.AckFrame) error {
}
func (h *sentPacketHandler) HasPacketForRetransmission() bool {
h.queuePacketsRTO()
h.maybeQueuePacketsRTO()
if len(h.retransmissionQueue) > 0 {
return true
@@ -290,6 +291,20 @@ func (h *sentPacketHandler) CheckForError() error {
return nil
}
func (h *sentPacketHandler) maybeQueuePacketsRTO() {
if time.Now().Before(h.TimeOfFirstRTO()) {
return
}
for p := h.highestInOrderAckedPacketNumber + 1; p <= h.lastSentPacketNumber; p++ {
packet := h.packetHistory[p]
if packet != nil && !packet.Retransmitted {
h.queuePacketForRetransmission(packet)
h.congestion.OnRetransmissionTimeout(true)
return
}
}
}
func (h *sentPacketHandler) getRTO() time.Duration {
rto := h.congestion.RetransmissionDelay()
if rto == 0 {
@@ -298,30 +313,9 @@ func (h *sentPacketHandler) getRTO() time.Duration {
return utils.MaxDuration(rto, protocol.MinRetransmissionTime)
}
func (h *sentPacketHandler) queuePacketsRTO() {
queued := false
now := time.Now()
for _, p := range h.packetHistory {
if p == nil || p.Retransmitted || p.rtoTime.After(now) {
continue
}
h.queuePacketForRetransmission(p)
queued = true
}
if queued {
h.congestion.OnRetransmissionTimeout(true)
}
}
func (h *sentPacketHandler) TimeOfFirstRTO() time.Time {
var min time.Time
for _, p := range h.packetHistory {
if p == nil || p.Retransmitted {
continue
}
if min.IsZero() || min.After(p.rtoTime) {
min = p.rtoTime
}
if h.lastSentPacketTime.IsZero() {
return time.Time{}
}
return min
return h.lastSentPacketTime.Add(h.getRTO())
}

39
ackhandler/sent_packet_handler_test.go
View File

@@ -6,7 +6,6 @@ import (
"github.com/lucas-clemente/quic-go/congestion"
"github.com/lucas-clemente/quic-go/frames"
"github.com/lucas-clemente/quic-go/protocol"
"github.com/lucas-clemente/quic-go/utils"
. "github.com/onsi/ginkgo"
. "github.com/onsi/gomega"
)
@@ -160,6 +159,13 @@ var _ = Describe("SentPacketHandler", func() {
Expect(err).ToNot(HaveOccurred())
Expect(handler.packetHistory[1].sendTime.Unix()).To(BeNumerically("~", time.Now().Unix(), 1))
})
It("updates the last sent time", func() {
packet := Packet{PacketNumber: 1, Frames: []frames.Frame{&streamFrame}, EntropyBit: true, Length: 1}
err := handler.SentPacket(&packet)
Expect(err).ToNot(HaveOccurred())
Expect(handler.lastSentPacketTime.Unix()).To(BeNumerically("~", time.Now().Unix(), 1))
})
})
Context("DOS mitigation", func() {
@@ -524,7 +530,7 @@ var _ = Describe("SentPacketHandler", func() {
// Simulate protocol.RetransmissionThreshold more NACKs
for i := uint8(0); i < protocol.RetransmissionThreshold; i++ {
_, err := handler.nackPacket(1)
_, err = handler.nackPacket(1)
Expect(err).ToNot(HaveOccurred())
}
Expect(handler.BytesInFlight()).To(Equal(protocol.ByteCount(0)))
@@ -612,8 +618,8 @@ var _ = Describe("SentPacketHandler", func() {
It("should call OnRetransmissionTimeout", func() {
err := handler.SentPacket(&Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1})
Expect(err).NotTo(HaveOccurred())
handler.packetHistory[1].rtoTime = time.Now().Add(-time.Second)
handler.queuePacketsRTO()
handler.lastSentPacketTime = time.Now().Add(-time.Second)
handler.maybeQueuePacketsRTO()
Expect(cong.onRetransmissionTimeout).To(BeTrue())
})
})
@@ -635,13 +641,6 @@ var _ = Describe("SentPacketHandler", func() {
handler.rttStats.UpdateRTT(rtt, 0, time.Now())
Expect(handler.getRTO()).To(Equal(protocol.MinRetransmissionTime))
})
It("stores RTO in sent packets", func() {
handler.SentPacket(&Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1})
val := handler.packetHistory[1].rtoTime
expected := time.Now().Add(protocol.DefaultRetransmissionTime)
Expect(utils.AbsDuration(expected.Sub(val))).To(BeNumerically("<", time.Millisecond))
})
})
Context("RTO retransmission", func() {
@@ -658,7 +657,7 @@ var _ = Describe("SentPacketHandler", func() {
It("ignores nil packets", func() {
handler.packetHistory[1] = nil
handler.queuePacketsRTO()
handler.maybeQueuePacketsRTO()
Expect(handler.TimeOfFirstRTO().IsZero()).To(BeTrue())
})
})
@@ -667,7 +666,7 @@ var _ = Describe("SentPacketHandler", func() {
It("does nothing if not required", func() {
err := handler.SentPacket(&Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1})
Expect(err).NotTo(HaveOccurred())
handler.queuePacketsRTO()
handler.maybeQueuePacketsRTO()
Expect(handler.retransmissionQueue).To(BeEmpty())
})
@@ -675,8 +674,8 @@ var _ = Describe("SentPacketHandler", func() {
p := &Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1}
err := handler.SentPacket(p)
Expect(err).NotTo(HaveOccurred())
handler.packetHistory[1].rtoTime = time.Now().Add(-time.Second)
handler.queuePacketsRTO()
handler.lastSentPacketTime = time.Now().Add(-time.Second)
handler.maybeQueuePacketsRTO()
Expect(handler.retransmissionQueue).To(HaveLen(1))
Expect(handler.retransmissionQueue[0]).To(Equal(p))
})
@@ -685,14 +684,14 @@ var _ = Describe("SentPacketHandler", func() {
p := &Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1, Retransmitted: true}
err := handler.SentPacket(p)
Expect(err).NotTo(HaveOccurred())
handler.packetHistory[1].rtoTime = time.Now().Add(-time.Second)
handler.queuePacketsRTO()
handler.lastSentPacketTime = time.Now().Add(-time.Second)
handler.maybeQueuePacketsRTO()
Expect(handler.retransmissionQueue).To(BeEmpty())
})
It("ignores nil packets", func() {
handler.packetHistory[1] = nil
handler.queuePacketsRTO()
handler.maybeQueuePacketsRTO()
Expect(handler.retransmissionQueue).To(BeEmpty())
})
})
@@ -701,7 +700,7 @@ var _ = Describe("SentPacketHandler", func() {
p := &Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1}
err := handler.SentPacket(p)
Expect(err).NotTo(HaveOccurred())
handler.packetHistory[1].rtoTime = time.Now().Add(-time.Second)
handler.lastSentPacketTime = time.Now().Add(-time.Second)
Expect(handler.HasPacketForRetransmission()).To(BeTrue())
})
@@ -709,7 +708,7 @@ var _ = Describe("SentPacketHandler", func() {
p := &Packet{PacketNumber: 1, Frames: []frames.Frame{}, Length: 1}
err := handler.SentPacket(p)
Expect(err).NotTo(HaveOccurred())
handler.packetHistory[1].rtoTime = time.Now().Add(-time.Second)
handler.lastSentPacketTime = time.Now().Add(-time.Second)
Expect(handler.DequeuePacketForRetransmission()).To(Equal(p))
})
})