netdev - Re: Wrong source MAC for 8021q VLAN interfaces with TX VLAN offload enabled

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Message-ID: <1394383187.2861.137.camel@deadeye.wl.decadent.org.uk>
Date:	Sun, 09 Mar 2014 16:39:47 +0000
From:	Ben Hutchings <ben@...adent.org.uk>
To:	Peter Boström <peter.bostrom@...rounds.com>
Cc:	netdev@...r.kernel.org
Subject: Re: Wrong source MAC for 8021q VLAN interfaces with TX VLAN offload
 enabled

On Tue, 2014-03-04 at 20:38 +0100, Peter Boström wrote:
> Hello
> 
> The patch committed as 2205369a314e12fcec4781cc73ac9c08fc2b47de (vlan:
> Fix header ops passthru when doing TX VLAN offload.) seems to have
> introduced a bug for me. It's reproducible in the current 3.14-rc5 as
> well as older versions for which the patch was applied.
[...]
> A potential fix is to set the saddr in the vlan_passthru_hard_header
> function.
> This works for me. But since I lack a good understanding of how the TX
> VLAN offload actually works I can't really tell whether this is a
> proper solution or not.
> Any input would be appreciated.
> 
> --- a/net/8021q/vlan_dev.c
> +++ b/net/8021q/vlan_dev.c
> @@ -538,6 +538,9 @@
>       struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
>       struct net_device *real_dev = vlan->real_dev;
> 
> +    if (!saddr)
> +        saddr = dev->dev_addr;
> +
>       return dev_hard_header(skb, real_dev, type, daddr, saddr, len);
>   }
> 

This makes sense to me.  You should re-send this patch with proper
formatting and your sign-off (see Documentation/SubmittingPatches,
Documentation/email-clients.txt).

Ben.

-- 
Ben Hutchings
I say we take off; nuke the site from orbit.  It's the only way to be sure.

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