From ed782b9f5a7a05debe944a33b4ac9e5629a95803 Mon Sep 17 00:00:00 2001 From: Michael Tuexen Date: Sun, 14 Feb 2021 12:10:31 +0100 Subject: tcp: improve behaviour when using TCP_NOOPT Use ISS for SEG.SEQ when sending a SYN-ACK segment in response to an SYN segment received in the SYN-SENT state on a socket having the IPPROTO_TCP level socket option TCP_NOOPT enabled. Reviewed by: rscheff Sponsored by: Netflix, Inc. Differential Revision: https://reviews.freebsd.org/D28656 --- sys/netinet/tcp_output.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'sys') diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c index cacc0c51bd8e..b4c7ab0a1ab7 100644 --- a/sys/netinet/tcp_output.c +++ b/sys/netinet/tcp_output.c @@ -785,6 +785,10 @@ send: #endif hdrlen = sizeof (struct tcpiphdr); + if (flags & TH_SYN) { + tp->snd_nxt = tp->iss; + } + /* * Compute options for segment. * We only have to care about SYN and established connection @@ -795,7 +799,6 @@ send: if ((tp->t_flags & TF_NOOPT) == 0) { /* Maximum segment size. */ if (flags & TH_SYN) { - tp->snd_nxt = tp->iss; to.to_mss = tcp_mssopt(&tp->t_inpcb->inp_inc); to.to_flags |= TOF_MSS; -- cgit v1.2.3