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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Pravin Shelar <pshelar@nicira.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>,
	netdev@vger.kernel.org, jesse@nicira.com, davem@davemloft.net
Subject: Re: [PATCH net] gre: Fix MTU sizing check for gretap tunnels
Date: Thu, 11 Jul 2013 15:45:02 -0700	[thread overview]
Message-ID: <1373582702.4600.85.camel@edumazet-glaptop> (raw)
In-Reply-To: <CALnjE+p3tqNO9Fbn=+LLtL8VvfvSQyOLDZoFRvGFTXgJzHKqhQ@mail.gmail.com>

On Thu, 2013-07-11 at 15:24 -0700, Pravin Shelar wrote:
> On Thu, Jul 11, 2013 at 1:12 PM, Alexander Duyck
> <alexander.h.duyck@intel.com> wrote:
> > This change fixes an MTU sizing issue seen with gretap tunnels when non-gso
> > packets are sent from the interface.
> >
> > In my case I was able to reproduce the issue by simply sending a ping of
> > 1421 bytes with the gretap interface created on a device with a standard
> > 1500 mtu.
> >
> > This fix is based on the fact that the tunnel mtu is already adjusted by
> > dev->hard_header_len so it would make sense that any packets being compared
> > against that mtu should also be adjusted by hard_header_len and the tunnel
> > header instead of just the tunnel header.
> >
> we can simplify code by not doing dev->hard_header_len adjustment to tunnel-mtu.
> 
> And right thing would be adjusting tunnel-mtu according to rt->dst.dev
> header-len so that we get mtu for out going path.

What's the mtu value we want to put in the ICMP message ?

  reply	other threads:[~2013-07-11 22:45 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-11 20:12 [PATCH net] gre: Fix MTU sizing check for gretap tunnels Alexander Duyck
2013-07-11 21:52 ` Eric Dumazet
2013-07-11 23:30   ` David Miller
2013-07-11 22:24 ` Pravin Shelar
2013-07-11 22:45   ` Eric Dumazet [this message]
2013-07-11 23:19     ` Pravin Shelar
2013-07-11 23:30       ` David Miller
2013-07-11 23:36       ` Jesse Gross
2013-07-12  0:13         ` Alexander Duyck
2013-07-12  1:11 ` Cong Wang

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