Date: Mon, 22 Jan 2007 11:11:23 -0800 From: Julian Elischer <julian@elischer.org> To: Steve Watt <steve@Watt.COM> Cc: andre@freebsd.org, Uwe Doering <gemini@geminix.org>, net@freebsd.org Subject: Re: Interesting TCP issue Message-ID: <45B50C5B.2080600@elischer.org> In-Reply-To: <200701221546.l0MFk27m081898@wattres.watt.com> References: <200701221546.l0MFk27m081898@wattres.watt.com>
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Steve Watt wrote:
> On Jan 22, 9:15, Uwe Doering wrote:
> } Subject: Re: Interesting TCP issue
> } Steve Watt wrote:
> } > 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.
> }
> } I wonder whether it is that easy. As far as I can tell the commit to
> } HEAD actually comprised changes to three files:
>
> I wonder as well, but that single diff fixes the problem I was running
> into with the skype mail servers.
>
> } http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_input.c.diff?r1=1.290&r2=1.291
> } http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_syncache.c.diff?r1=1.84&r2=1.85
> } http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_var.h.diff?r1=1.127&r2=1.128
> }
> } How about the modifications in 'tcp_input.c'? Are they relevant to the
> } problem this thread is about? If so, assessing the correctness of an
> } MFC might prove to be a little harder.
That's why I asked Andre to look at it but he's not responding..
>
> Looking at it, yeah, those probably need to be picked up in some form as
> well. I didn't look closely at the tcpdump after, only observing that
> it worked where it didn't before.
>
> Hmm.
>
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