Date: Sat, 20 Jan 2007 01:18:42 -0800 From: steve@Watt.COM (Steve Watt) To: julian@elischer.org Cc: hackers@freebsd.org, andre@freebsd.org Subject: Re: Interesting TCP issue Message-ID: <200701200918.l0K9Igbn002427@wattres.watt.com> In-Reply-To: <459AD141.5010502@elischer.org> References: <200701020825.l028PMBK034571@wattres.watt.com>
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In <459AD141.5010502@elischer.org>, Julian Elischer wrote: [ Snip discussion of symptoms of window scaling broken when talking to at least the skype mail servers. ] >we have seen this since 4.x >I think a fix may be in 7.0 but I'm not sure.. >I thin kthere is a problem when the far end sets the window down to 1 >but scales it by a factor of 2^{big number}. > >Andre, can you check out this problem and MFC the correct fix >if it is indeed the same problem in 6.2? It is the same problem; I took the (one-line) fix as indicated by >http://cvs.ironport.com/cgi-bin/viewcvs.cgi/freebsd/src/sys/netinet/tcp_syncache.c.diff?r1=1.84&r2=1.85 (well, not cvs.ironport.com, which doesn't seem to exist at the moment), and applied the diff from 1.84 to 1.85 and to a 6.2-PRERELEASE box updated around 25 Dec 06. It works like a charm. I would vote to MFC 1.85 now that 6.2 is out. The diff, for those who are following along at home, is: =================================================================== RCS file: /usr/local/www/cvsroot/FreeBSD/src/sys/netinet/tcp_syncache.c,v retrieving revision 1.84 retrieving revision 1.85 diff -u -p -r1.84 -r1.85 --- src/sys/netinet/tcp_syncache.c 2006/02/09 21:29:02 1.84 +++ src/sys/netinet/tcp_syncache.c 2006/02/28 23:05:59 1.85 @@ -682,7 +682,7 @@ syncache_socket(sc, lso, m) tp->t_flags |= TF_NOOPT; if (sc->sc_flags & SCF_WINSCALE) { tp->t_flags |= TF_REQ_SCALE|TF_RCVD_SCALE; - tp->requested_s_scale = sc->sc_requested_s_scale; + tp->snd_scale = sc->sc_requested_s_scale; tp->request_r_scale = sc->sc_request_r_scale; } if (sc->sc_flags & SCF_TIMESTAMP) { -- Steve Watt KD6GGD PP-ASEL-IA ICBM: 121W 56' 57.5" / 37N 20' 15.3" Internet: steve @ Watt.COM Whois: SW32-ARIN Free time? There's no such thing. It just comes in varying prices...
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