The branch main has been updated by tuexen: URL: https://cgit.FreeBSD.org/src/commit/?id=2515552e6216095c3fa61d93ee024bb8861e07c2
commit 2515552e6216095c3fa61d93ee024bb8861e07c2 Author: Michael Tuexen <[email protected]> AuthorDate: 2022-10-03 12:46:47 +0000 Commit: Michael Tuexen <[email protected]> CommitDate: 2022-10-03 12:46:47 +0000 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 --- sys/netinet/tcp_timewait.c | 6 +++--- 1 file 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);
