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-rw-r--r--pkg/tcpip/stack/stack.go3
-rw-r--r--pkg/tcpip/transport/tcp/endpoint.go1
-rw-r--r--pkg/tcpip/transport/tcp/snd.go35
-rw-r--r--pkg/tcpip/transport/tcp/tcp_sack_test.go42
4 files changed, 71 insertions, 10 deletions
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index dc4f5b3e7..026d330c4 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -171,6 +171,9 @@ type TCPSenderState struct {
// Outstanding is the number of packets in flight.
Outstanding int
+ // SackedOut is the number of packets which have been selectively acked.
+ SackedOut int
+
// SndWnd is the send window size in bytes.
SndWnd seqnum.Size
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 7a37c10bb..bb0795f78 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -2989,6 +2989,7 @@ func (e *endpoint) completeState() stack.TCPEndpointState {
Ssthresh: e.snd.sndSsthresh,
SndCAAckCount: e.snd.sndCAAckCount,
Outstanding: e.snd.outstanding,
+ SackedOut: e.snd.sackedOut,
SndWnd: e.snd.sndWnd,
SndUna: e.snd.sndUna,
SndNxt: e.snd.sndNxt,
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index baec762e1..cc991aba6 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -137,6 +137,9 @@ type sender struct {
// that have been sent but not yet acknowledged.
outstanding int
+ // sackedOut is the number of packets which are selectively acked.
+ sackedOut int
+
// sndWnd is the send window size.
sndWnd seqnum.Size
@@ -372,6 +375,7 @@ func (s *sender) updateMaxPayloadSize(mtu, count int) {
m = 1
}
+ oldMSS := s.maxPayloadSize
s.maxPayloadSize = m
if s.gso {
s.ep.gso.MSS = uint16(m)
@@ -394,6 +398,7 @@ func (s *sender) updateMaxPayloadSize(mtu, count int) {
// Rewind writeNext to the first segment exceeding the MTU. Do nothing
// if it is already before such a packet.
+ nextSeg := s.writeNext
for seg := s.writeList.Front(); seg != nil; seg = seg.Next() {
if seg == s.writeNext {
// We got to writeNext before we could find a segment
@@ -401,16 +406,22 @@ func (s *sender) updateMaxPayloadSize(mtu, count int) {
break
}
- if seg.data.Size() > m {
+ if nextSeg == s.writeNext && seg.data.Size() > m {
// We found a segment exceeding the MTU. Rewind
// writeNext and try to retransmit it.
- s.writeNext = seg
- break
+ nextSeg = seg
+ }
+
+ if s.ep.sackPermitted && s.ep.scoreboard.IsSACKED(seg.sackBlock()) {
+ // Update sackedOut for new maximum payload size.
+ s.sackedOut -= s.pCount(seg, oldMSS)
+ s.sackedOut += s.pCount(seg, s.maxPayloadSize)
}
}
// Since we likely reduced the number of outstanding packets, we may be
// ready to send some more.
+ s.writeNext = nextSeg
s.sendData()
}
@@ -629,13 +640,13 @@ func (s *sender) retransmitTimerExpired() bool {
// pCount returns the number of packets in the segment. Due to GSO, a segment
// can be composed of multiple packets.
-func (s *sender) pCount(seg *segment) int {
+func (s *sender) pCount(seg *segment, maxPayloadSize int) int {
size := seg.data.Size()
if size == 0 {
return 1
}
- return (size-1)/s.maxPayloadSize + 1
+ return (size-1)/maxPayloadSize + 1
}
// splitSeg splits a given segment at the size specified and inserts the
@@ -1023,7 +1034,7 @@ func (s *sender) sendData() {
break
}
dataSent = true
- s.outstanding += s.pCount(seg)
+ s.outstanding += s.pCount(seg, s.maxPayloadSize)
s.writeNext = seg.Next()
}
@@ -1038,6 +1049,7 @@ func (s *sender) enterRecovery() {
// We inflate the cwnd by 3 to account for the 3 packets which triggered
// the 3 duplicate ACKs and are now not in flight.
s.sndCwnd = s.sndSsthresh + 3
+ s.sackedOut = 0
s.fr.first = s.sndUna
s.fr.last = s.sndNxt - 1
s.fr.maxCwnd = s.sndCwnd + s.outstanding
@@ -1207,6 +1219,7 @@ func (s *sender) walkSACK(rcvdSeg *segment) {
s.rc.update(seg, rcvdSeg, s.ep.tsOffset)
s.rc.detectReorder(seg)
seg.acked = true
+ s.sackedOut += s.pCount(seg, s.maxPayloadSize)
}
seg = seg.Next()
}
@@ -1380,10 +1393,10 @@ func (s *sender) handleRcvdSegment(rcvdSeg *segment) {
datalen := seg.logicalLen()
if datalen > ackLeft {
- prevCount := s.pCount(seg)
+ prevCount := s.pCount(seg, s.maxPayloadSize)
seg.data.TrimFront(int(ackLeft))
seg.sequenceNumber.UpdateForward(ackLeft)
- s.outstanding -= prevCount - s.pCount(seg)
+ s.outstanding -= prevCount - s.pCount(seg, s.maxPayloadSize)
break
}
@@ -1399,11 +1412,13 @@ func (s *sender) handleRcvdSegment(rcvdSeg *segment) {
s.writeList.Remove(seg)
- // If SACK is enabled then Only reduce outstanding if
+ // If SACK is enabled then only reduce outstanding if
// the segment was not previously SACKED as these have
// already been accounted for in SetPipe().
if !s.ep.sackPermitted || !s.ep.scoreboard.IsSACKED(seg.sackBlock()) {
- s.outstanding -= s.pCount(seg)
+ s.outstanding -= s.pCount(seg, s.maxPayloadSize)
+ } else {
+ s.sackedOut -= s.pCount(seg, s.maxPayloadSize)
}
seg.decRef()
ackLeft -= datalen
diff --git a/pkg/tcpip/transport/tcp/tcp_sack_test.go b/pkg/tcpip/transport/tcp/tcp_sack_test.go
index ef7f5719f..faf0c0ad7 100644
--- a/pkg/tcpip/transport/tcp/tcp_sack_test.go
+++ b/pkg/tcpip/transport/tcp/tcp_sack_test.go
@@ -590,3 +590,45 @@ func TestSACKRecovery(t *testing.T) {
expected++
}
}
+
+// TestSACKUpdateSackedOut tests the sacked out field is updated when a SACK
+// is received.
+func TestSACKUpdateSackedOut(t *testing.T) {
+ c := context.New(t, uint32(mtu))
+ defer c.Cleanup()
+
+ probeDone := make(chan struct{})
+ ackNum := 0
+ c.Stack().AddTCPProbe(func(state stack.TCPEndpointState) {
+ // Validate that the endpoint Sender.SackedOut is what we expect.
+ if state.Sender.SackedOut != 2 && ackNum == 0 {
+ t.Fatalf("SackedOut got updated to wrong value got: %v want: 2", state.Sender.SackedOut)
+ }
+
+ if state.Sender.SackedOut != 0 && ackNum == 1 {
+ t.Fatalf("SackedOut got updated to wrong value got: %v want: 0", state.Sender.SackedOut)
+ }
+ if ackNum > 0 {
+ close(probeDone)
+ }
+ ackNum++
+ })
+ setStackSACKPermitted(t, c, true)
+ createConnectedWithSACKAndTS(c)
+
+ sendAndReceive(t, c, 8)
+
+ // ACK for [3-5] packets.
+ seq := seqnum.Value(context.TestInitialSequenceNumber).Add(1)
+ start := c.IRS.Add(seqnum.Size(1 + 3*maxPayload))
+ bytesRead := 2 * maxPayload
+ end := start.Add(seqnum.Size(bytesRead))
+ c.SendAckWithSACK(seq, bytesRead, []header.SACKBlock{{start, end}})
+
+ bytesRead += 3 * maxPayload
+ c.SendAck(seq, bytesRead)
+
+ // Wait for the probe function to finish processing the ACK before the
+ // test completes.
+ <-probeDone
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-29 01:44:36 +0000