netdev - Re: [PATCH net-next 2/2] openvswitch: Fix skb->protocol for vlan frames.

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Message-ID: <20161124171046.7eb0e287@griffin>
Date:   Thu, 24 Nov 2016 17:10:46 +0100
From:   Jiri Benc <jbenc@...hat.com>
To:     Jarno Rajahalme <jarno@....org>
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH net-next 2/2] openvswitch: Fix skb->protocol for vlan
 frames.

On Tue, 22 Nov 2016 20:09:34 -0800, Jarno Rajahalme wrote:
> Do not set skb->protocol to be the ethertype of the L3 header, unless
> the packet only has the L3 header.  For a non-hardware offloaded VLAN
> frame skb->protocol needs to be one of the VLAN ethertypes.
> 
> Any VLAN offloading is undone on the OVS netlink interface.  Due to
> this all VLAN packets sent to openvswitch module from userspace are
> non-offloaded.

This is exactly why I wanted to always accelerate the vlan tag, the
same way it is done in other parts of the networking stack: to prevent
all those weird corner cases.

Looks to me this is the only real way forward.

This patch is wrong, it would leave skb->protocol as ETH_P_TEB for L2
frames received via ARPHRD_NONE interface.

 Jiri