From: Patrick McHardy <kaber@trash.net>
To: Indan Zupancic <indan@nul.nu>
Cc: netfilter-devel@lists.netfilter.org, gandalf@wlug.westbo.se,
Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>
Subject: Re: 2.6.23-rc1: ipv4_get_l4proto: Frag of proto 17
Date: Thu, 26 Jul 2007 13:17:22 +0200 [thread overview]
Message-ID: <46A882C2.6000206@trash.net> (raw)
In-Reply-To: <49914.81.207.0.53.1185448638.squirrel@secure.samage.net>
Indan Zupancic wrote:
>
> Reading the comment in icmp.c iph->frag_off & htons(IP_OFFSET)
> being true means that it's a fragment, but not the first one.
>
> So what's happening is that the host sends a big UDP packet, it gets
> fragmentated, but never reaches its destination. ICMP error packets
> are generated. Conntrack drops the latter ones thanks to the check in
> ipv4_get_l4proto.
>
> So the question is whether those latter ICMP packets should be forwarded
> or not. If not, the code is fine and the warning message could be removed.
> If they should, then it might be hard for the current conntrack code know
> where to send the packet, as the UDP header is missing.
Yes, we can't associate them with the original connection.
We should catch this case in ICMP tracking though I think
instead of removing the message.
prev parent reply other threads:[~2007-07-26 11:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-24 23:24 2.6.23-rc1: ipv4_get_l4proto: Frag of proto 17 Indan Zupancic
2007-07-25 15:19 ` Patrick McHardy
2007-07-25 16:12 ` Indan Zupancic
2007-07-25 16:17 ` Patrick McHardy
2007-07-25 17:02 ` Indan Zupancic
2007-07-25 17:13 ` Martin Josefsson
2007-07-25 17:41 ` Indan Zupancic
2007-07-26 1:27 ` Yasuyuki KOZAKAI
[not found] ` <200707260127.l6Q1RPP6019173@toshiba.co.jp>
2007-07-26 9:46 ` Indan Zupancic
2007-07-26 9:50 ` Patrick McHardy
2007-07-26 10:09 ` Indan Zupancic
2007-07-26 10:22 ` Patrick McHardy
2007-07-26 11:17 ` Indan Zupancic
2007-07-26 11:17 ` Patrick McHardy [this message]
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