From: Vladimir Ivaschenko <hazard@francoudi.com>
To: Andi Kleen <ak@suse.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: sendmsg() leaves Identification field in IP header empty
Date: Wed, 5 Dec 2001 22:22:35 +0200 [thread overview]
Message-ID: <20011205222235.A7572@francoudi.com> (raw)
In-Reply-To: <3C0E6F8B.A6C85AB6@francoudi.com.suse.lists.linux.kernel> <p73d71t8md0.fsf@amdsim2.suse.de>
In-Reply-To: <p73d71t8md0.fsf@amdsim2.suse.de>; from ak@suse.de on Wed, Dec 05, 2001 at 09:04:27PM +0100
Andi Kleen wrote about "Re: sendmsg() leaves Identification field in IP header empty":
>
> In theory the hack from TCP could be ported to UDP too, but I'm not sure if it is
> worth it for WCCP (to be honest I don't know what WCCP is so I cannot assess if
> it's important enough to add a workaround for it)
Andi, thanks a lot for the insight, I will try your suggestions.
WCCP is a Web Cache Communication Protocol; it is used by Cisco
routers to forward traffic to proxies. What is confusing is that
send() generates an ID for packets with DF set, at least when
used in a way like Squid uses it. I briefly checked Squid source
code and didn't find any places where it would disable MTU Path
discovery.
> > Sorry if I'm wrong but I think this is a kernel problem because
> > sendmsg() is a system call. On RH6.2 with 2.2.19 this doesn't happen,
>
> It's strictly not a bug because the RFCs don't require an IPID for !DF.
Ok, an intercompatibility issue. :-)
--
Best Regards
Vladimir Ivaschenko
Certified Linux Engineer (RHCE)
next prev parent reply other threads:[~2001-12-05 20:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3C0E6F8B.A6C85AB6@francoudi.com.suse.lists.linux.kernel>
2001-12-05 20:04 ` sendmsg() leaves Identification field in IP header empty Andi Kleen
2001-12-05 20:22 ` Vladimir Ivaschenko [this message]
2001-12-05 19:03 Vladimir Ivaschenko
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