From d57f539d00971e49703bb5b1e12f05a1c6cd50fb Mon Sep 17 00:00:00 2001 From: jlemon Date: Wed, 26 Feb 2003 18:20:41 +0000 Subject: In timewait state, if the incoming segment is a pure in-sequence ack that matches snd_max, then do not respond with an ack, just drop the segment. This fixes a problem where a simultaneous close results in an ack loop between two time-wait states. Test case supplied by: Tim Robbins Sponsored by: DARPA, NAI Labs --- sys/netinet/tcp_reass.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'sys/netinet/tcp_reass.c') diff --git a/sys/netinet/tcp_reass.c b/sys/netinet/tcp_reass.c index 2fec783..7b4827a 100644 --- a/sys/netinet/tcp_reass.c +++ b/sys/netinet/tcp_reass.c @@ -2913,9 +2913,11 @@ tcp_timewait(tw, to, th, m, tlen) } /* - * Acknowlege the segment, then drop it. + * Acknowledge the segment if it has data or is not a duplicate ACK. */ - tcp_twrespond(tw, TH_ACK); + if (thflags != TH_ACK || tlen != 0 || + th->th_seq != tw->rcv_nxt || th->th_ack != tw->snd_nxt) + tcp_twrespond(tw, TH_ACK); goto drop; reset: -- cgit v1.1