netdev - Re: [PATCH net] gso_segment: Reset skb->mac_len after modifying network header

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Message-ID: <85765D69-F7BA-48A8-9954-595DEA22EE37@toke.dk>
Date:   Thu, 13 Sep 2018 16:22:24 +0200
From:   Toke Høiland-Jørgensen <toke@...e.dk>
To:     Eric Dumazet <eric.dumazet@...il.com>, netdev@...r.kernel.org
CC:     cake@...ts.bufferbloat.net, Eric Dumazet <edumazet@...gle.com>
Subject: Re: [PATCH net] gso_segment: Reset skb->mac_len after modifying network header



On 13 September 2018 16:11:18 CEST, Eric Dumazet <eric.dumazet@...il.com> wrote:
>
>
>On 09/11/2018 03:19 PM, Toke Høiland-Jørgensen wrote:
>> When splitting a GSO segment that consists of encapsulated packets,
>the
>> skb->mac_len of the segments can end up being set wrong, causing
>packet
>> drops in particular when using act_mirred and ifb interfaces in
>> combination with a qdisc that splits GSO packets.
>> 
>> This happens because at the time skb_segment() is called,
>network_header
>> will point to the inner header, throwing off the calculation in
>> skb_reset_mac_len(). The network_header is subsequently adjust by the
>> outer IP gso_segment handlers, but they don't set the mac_len.
>> 
>> Fix this by adding skb_reset_mac_len() calls to both the IPv4 and
>IPv6
>> gso_segment handlers, after they modify the network_header.
>> 
>> Signed-off-by: Toke Høiland-Jørgensen <toke@...e.dk>
>
>Looks good but I would have appreciated a thanks or something
>after the help I gave on this problem.

Yes, of course. Should have mentioned that in the commit message.

My apologies, won't happen again. And thanks! :)

-Toke