diff options
Diffstat (limited to 'pkg/tcpip/transport/tcp')
| -rw-r--r-- | pkg/tcpip/transport/tcp/endpoint.go | 1 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/snd.go | 35 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/tcp_sack_test.go | 42 |
3 files changed, 68 insertions, 10 deletions
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 +} |