netdev - Re: [PATCH net] ip6_tunnel: Account for tunnel header in tunnel MTU

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Date:   Mon, 16 Jan 2017 13:23:54 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     jkbs@...hat.com
Cc:     netdev@...r.kernel.org, tom@...bertland.com
Subject: Re: [PATCH net] ip6_tunnel: Account for tunnel header in tunnel MTU

From: Jakub Sitnicki <jkbs@...hat.com>
Date: Fri, 13 Jan 2017 10:12:20 +0100

> With ip6gre we have a tunnel header which also makes the tunnel MTU
> smaller. We need to reserve room for it. Previously we were using up
> space reserved for the Tunnel Encapsulation Limit option
> header (RFC 2473).
> 
> Also, after commit b05229f44228 ("gre6: Cleanup GREv6 transmit path,
> call common GRE functions") our contract with the caller has
> changed. Now we check if the packet length exceeds the tunnel MTU after
> the tunnel header has been pushed, unlike before.
> 
> This is reflected in the check where we look at the packet length minus
> the size of the tunnel header, which is already accounted for in tunnel
> MTU.
> 
> Fixes: b05229f44228 ("gre6: Cleanup GREv6 transmit path, call common GRE functions")
> Signed-off-by: Jakub Sitnicki <jkbs@...hat.com>

Applied and queued up for -stable, thanks.