Interesting TCP issue

[Julian Elischer]

Steve Watt wrote:
> On Jan 22,  9:15, Uwe Doering wrote:
> } Subject: Re: Interesting TCP issue
> } Steve Watt wrote:
> } > In <459AD141.5010502 at 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.
>