Date: Tue, 18 Oct 2016 02:40:25 +0000 (UTC) From: Hiren Panchasara <hiren@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r307545 - head/sys/netinet Message-ID: <201610180240.u9I2ePK9052447@repo.freebsd.org>
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Author: hiren Date: Tue Oct 18 02:40:25 2016 New Revision: 307545 URL: https://svnweb.freebsd.org/changeset/base/307545 Log: Make sure tcp_mss() has the same check as tcp_mss_update() to have t_maxseg set to at least 64. This is still just a coverup to avoid kernel panic and not an actual fix. PR: 213232 Reviewed by: glebius MFC after: 1 week Sponsored by: Limelight Networks Differential Revision: https://reviews.freebsd.org/D8272 Modified: head/sys/netinet/tcp_input.c Modified: head/sys/netinet/tcp_input.c ============================================================================== --- head/sys/netinet/tcp_input.c Tue Oct 18 01:55:07 2016 (r307544) +++ head/sys/netinet/tcp_input.c Tue Oct 18 02:40:25 2016 (r307545) @@ -3758,7 +3758,15 @@ tcp_mss(struct tcpcb *tp, int offer) (void)sbreserve_locked(&so->so_snd, bufsize, so, NULL); } SOCKBUF_UNLOCK(&so->so_snd); - tp->t_maxseg = mss; + /* + * Sanity check: make sure that maxseg will be large + * enough to allow some data on segments even if the + * all the option space is used (40bytes). Otherwise + * funny things may happen in tcp_output. + * + * XXXGL: shouldn't we reserve space for IP/IPv6 options? + */ + tp->t_maxseg = max(mss, 64); SOCKBUF_LOCK(&so->so_rcv); if ((so->so_rcv.sb_hiwat == V_tcp_recvspace) && metrics.rmx_recvpipe)
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