The branch main has been updated by tuexen: URL: https://cgit.FreeBSD.org/src/commit/?id=f3364d3c8c876074a9a6f68168e5eb8bd60207de
commit f3364d3c8c876074a9a6f68168e5eb8bd60207de Author: Michael Tuexen <[email protected]> AuthorDate: 2026-02-25 13:06:15 +0000 Commit: Michael Tuexen <[email protected]> CommitDate: 2026-02-25 13:06:15 +0000 tcp: improve handling of segments in TIME WAIT The check for excluding duplicate ACKs needs to consider only TH_SYN and TH_FIN. We know that TH_ACK is set and TH_RST is cleared. All other flags, in particular TH_ECE, TH_CWR, and TH_AE needs to be ignored for the check. PR: 292293 Reviewed by: rrs MFC after: 3 days Sponsored by: Netflix, Inc. Differential Revision: https://reviews.freebsd.org/D55489 --- sys/netinet/tcp_timewait.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c index 847598422da5..ba5c90c91e43 100644 --- a/sys/netinet/tcp_timewait.c +++ b/sys/netinet/tcp_timewait.c @@ -287,7 +287,7 @@ tcp_twcheck(struct inpcb *inp, struct tcpopt *to, struct tcphdr *th, /* * Acknowledge the segment if it has data or is not a duplicate ACK. */ - if (thflags != TH_ACK || tlen != 0 || + if ((thflags & (TH_SYN | TH_FIN)) != 0 || tlen != 0 || th->th_seq != tp->rcv_nxt || th->th_ack != tp->snd_nxt) { TCP_LOG_EVENT(tp, th, NULL, NULL, TCP_LOG_IN, 0, tlen, NULL, true);
