diff options
Diffstat (limited to 'pkg/tcpip/transport')
| -rw-r--r-- | pkg/tcpip/transport/tcp/snd.go | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go index 0fee7ab72..1f9b1e0ef 100644 --- a/pkg/tcpip/transport/tcp/snd.go +++ b/pkg/tcpip/transport/tcp/snd.go @@ -39,6 +39,28 @@ const ( nDupAckThreshold = 3 ) +// ccState indicates the current congestion control state for this sender. +type ccState int + +const ( + // Open indicates that the sender is receiving acks in order and + // no loss or dupACK's etc have been detected. + Open ccState = iota + // RTORecovery indicates that an RTO has occurred and the sender + // has entered an RTO based recovery phase. + RTORecovery + // FastRecovery indicates that the sender has entered FastRecovery + // based on receiving nDupAck's. This state is entered only when + // SACK is not in use. + FastRecovery + // SACKRecovery indicates that the sender has entered SACK based + // recovery. + SACKRecovery + // Disorder indicates the sender either received some SACK blocks + // or dupACK's. + Disorder +) + // congestionControl is an interface that must be implemented by any supported // congestion control algorithm. type congestionControl interface { @@ -138,6 +160,9 @@ type sender struct { // maxSentAck is the maxium acknowledgement actually sent. maxSentAck seqnum.Value + // state is the current state of congestion control for this endpoint. + state ccState + // cc is the congestion control algorithm in use for this sender. cc congestionControl } @@ -435,6 +460,7 @@ func (s *sender) retransmitTimerExpired() bool { s.leaveFastRecovery() } + s.state = RTORecovery s.cc.HandleRTOExpired() // Mark the next segment to be sent as the first unacknowledged one and @@ -820,9 +846,11 @@ func (s *sender) enterFastRecovery() { s.fr.last = s.sndNxt - 1 s.fr.maxCwnd = s.sndCwnd + s.outstanding if s.ep.sackPermitted { + s.state = SACKRecovery s.ep.stack.Stats().TCP.SACKRecovery.Increment() return } + s.state = FastRecovery s.ep.stack.Stats().TCP.FastRecovery.Increment() } @@ -981,6 +1009,7 @@ func (s *sender) checkDuplicateAck(seg *segment) (rtx bool) { s.fr.highRxt = s.sndUna - 1 // Do run SetPipe() to calculate the outstanding segments. s.SetPipe() + s.state = Disorder return false } @@ -1112,6 +1141,9 @@ func (s *sender) handleRcvdSegment(seg *segment) { // window based on the number of acknowledged packets. if !s.fr.active { s.cc.Update(originalOutstanding - s.outstanding) + if s.fr.last.LessThan(s.sndUna) { + s.state = Open + } } // It is possible for s.outstanding to drop below zero if we get |