From: Maxime Bizon <mbizon@freebox.fr>
To: Patrick McHardy <kaber@trash.net>
Cc: Eric Dumazet <edumazet@google.com>,
davem@davemloft.net, netdev <netdev@vger.kernel.org>
Subject: Re: problem forwarding IP fragments with DF bit set (caused by ipv4: fix path MTU discovery with connection tracking)
Date: Tue, 29 Apr 2014 17:23:41 +0200 [thread overview]
Message-ID: <1398785021.4033.19.camel@sakura.staff.proxad.net> (raw)
In-Reply-To: <20140429144513.GA12969@macbook.localnet>
On Tue, 2014-04-29 at 15:45 +0100, Patrick McHardy wrote:
> Right, that is not correct of course. We save the original packet size
> and should either refragment to that size or send an ICMP frag required
> if the original size exceeds the outgoing MTU.
yep indeed, if any fragment is bigger than outgoing MTU
> So your patch does look correct, however we should probably only set
> local_df in conntrack defrag.
I thought of putting it in conntrack code first, but I had some doubts.
There are a lot of possible paths that can be taken after reassembly
(ipsec, tunnel, ...), and I did not audit all of them.
Since the patch that caused this regression modified the generic
fragmentation code, it may have caused other silent breakage.
Eric/David, could I get your feeling about this ?
Thanks,
--
Maxime
next prev parent reply other threads:[~2014-04-29 15:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-28 16:37 problem forwarding IP fragments with DF bit set (caused by ipv4: fix path MTU discovery with connection tracking) Maxime Bizon
2014-04-28 17:59 ` Maxime Bizon
2014-04-29 14:35 ` Patrick McHardy
2014-04-29 14:33 ` Patrick McHardy
2014-04-29 14:42 ` Maxime Bizon
2014-04-29 14:45 ` Patrick McHardy
2014-04-29 15:23 ` Maxime Bizon [this message]
2014-04-29 15:37 ` Eric Dumazet
2014-04-29 20:13 ` Florian Westphal
2014-04-30 14:34 ` Maxime Bizon
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