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| author | Michael Tuexen <tuexen@FreeBSD.org> | 2022-10-03 12:46:47 +0000 |
|---|---|---|
| committer | Michael Tuexen <tuexen@FreeBSD.org> | 2022-10-03 12:46:47 +0000 |
| commit | 2515552e6216095c3fa61d93ee024bb8861e07c2 (patch) | |
| tree | 769a9250fdae989b32c6310d19f0d1f22d9f2391 | |
| parent | dcdba3460dd779a0180ec7769ab8cd47c932799e (diff) | |
| download | src-2515552e6216095c3fa61d93ee024bb8861e07c2.tar.gz src-2515552e6216095c3fa61d93ee024bb8861e07c2.zip | |
tcp: improve handling of SYN-ACK segments in TIMEWAIT state
Only consider segments with the SYN bit set and the ACK bit cleared
as "new connection attempts", which result in re-using a connection
being in TIMEWAIT state. This results in consistent handling of
SYN-ACK segments.
Reviewed by: rscheff@
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D36864
| -rw-r--r-- | sys/netinet/tcp_timewait.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c index ad97e2d3bed6..272734924384 100644 --- a/sys/netinet/tcp_timewait.c +++ b/sys/netinet/tcp_timewait.c @@ -464,13 +464,13 @@ tcp_twcheck(struct inpcb *inp, struct tcpopt *to, struct tcphdr *th, * are above the previous ones. * Allow UDP port number changes in this case. */ - if ((thflags & TH_SYN) && SEQ_GT(th->th_seq, tw->rcv_nxt)) { + if (((thflags & (TH_SYN | TH_ACK)) == TH_SYN) && + SEQ_GT(th->th_seq, tw->rcv_nxt)) { /* * In case we can't upgrade our lock just pretend we have * lost this packet. */ - if (((thflags & (TH_SYN | TH_ACK)) == TH_SYN) && - INP_TRY_UPGRADE(inp) == 0) + if (INP_TRY_UPGRADE(inp) == 0) goto drop; tcp_twclose(tw, 0); TCPSTAT_INC(tcps_tw_recycles); |