diff options
Diffstat (limited to 'pkg/tcpip/transport/tcp/rcv.go')
| -rw-r--r-- | pkg/tcpip/transport/tcp/rcv.go | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/pkg/tcpip/transport/tcp/rcv.go b/pkg/tcpip/transport/tcp/rcv.go index b08a0e356..f02fa6105 100644 --- a/pkg/tcpip/transport/tcp/rcv.go +++ b/pkg/tcpip/transport/tcp/rcv.go @@ -134,6 +134,7 @@ func (r *receiver) consumeSegment(s *segment, segSeq seqnum.Value, segLen seqnum // sequence numbers that have been consumed. TrimSACKBlockList(&r.ep.sack, r.rcvNxt) + // Handle FIN or FIN-ACK. if s.flagIsSet(header.TCPFlagFin) { r.rcvNxt++ @@ -144,6 +145,25 @@ func (r *receiver) consumeSegment(s *segment, segSeq seqnum.Value, segLen seqnum r.closed = true r.ep.readyToRead(nil) + // We just received a FIN, our next state depends on whether we sent a + // FIN already or not. + r.ep.mu.Lock() + switch r.ep.state { + case StateEstablished: + r.ep.state = StateCloseWait + case StateFinWait1: + if s.flagIsSet(header.TCPFlagAck) { + // FIN-ACK, transition to TIME-WAIT. + r.ep.state = StateTimeWait + } else { + // Simultaneous close, expecting a final ACK. + r.ep.state = StateClosing + } + case StateFinWait2: + r.ep.state = StateTimeWait + } + r.ep.mu.Unlock() + // Flush out any pending segments, except the very first one if // it happens to be the one we're handling now because the // caller is using it. @@ -156,6 +176,23 @@ func (r *receiver) consumeSegment(s *segment, segSeq seqnum.Value, segLen seqnum r.pendingRcvdSegments[i].decRef() } r.pendingRcvdSegments = r.pendingRcvdSegments[:first] + + return true + } + + // Handle ACK (not FIN-ACK, which we handled above) during one of the + // shutdown states. + if s.flagIsSet(header.TCPFlagAck) { + r.ep.mu.Lock() + switch r.ep.state { + case StateFinWait1: + r.ep.state = StateFinWait2 + case StateClosing: + r.ep.state = StateTimeWait + case StateLastAck: + r.ep.state = StateClose + } + r.ep.mu.Unlock() } return true |