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Subject: Re: [PATCH net-next-2.6] net/ipv4: push IP options to CB in
 ip_fragment
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Herbert Xu <herbert@gondor.hengli.com.au>
Cc: Bandan Das <bandan.das@stratus.com>, David Miller <davem@davemloft.net>,
        NetDev <netdev@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Patrick McHardy <kaber@trash.net>
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Date: Tue, 31 Aug 2010 11:17:51 +0200
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Le mardi 31 août 2010 à 16:24 +0800, Herbert Xu a écrit :
> On Tue, Aug 31, 2010 at 07:20:31AM +0200, Eric Dumazet wrote:
> > Le lundi 30 août 2010 à 19:21 -0400, Bandan Das a écrit :
> > > > 
> > > > I wonder if we want this.
> > > > 
> > > > Maybe setting skb->local_df = 1 in bridge should be enough ?
> > > > 
> > > > 
> > > Thanks Eric for looking at this. Indeed, setting local_df to 1 seems to be enough! I will
> > > respin and post a different patch.
> > > 
> > 
> > Reading this stuff again, I wonder if we should not revert commit
> > 17762060c25590bfddd  and use a different trick
> 
> I don't quite understand the problem.  Does the packet actually
> have IP options? If not why is it trying to look at IP options?
> 
> If it does have options, then we should parse options in the
> bridge driver before passing it to the IP stack (or just drop
> the packet).

Once again, the IP stack -> bridge -> IP stack flow bites us,
because bridge likes to dirty IPCB.

We can correct every bug we find once in a while (you did in commit
17762060c255 for a particular bug), or just make bridge not touch IPCB.