Subject: Re: linux-next: Tree for Aug 7

From: Johannes Berg <[email-masked]>
Date: Wed, 07 Aug 2013 18:22:02 +0200

On Wed, 2013-08-07 at 09:17 -0700, Eric Dumazet wrote:
> On Wed, 2013-08-07 at 18:12 +0200, Johannes Berg wrote:
> > On Wed, 2013-08-07 at 17:59 +0200, Phil Sutter wrote:
> > 
> > > The idea behind this patch is that users setting the protocol to
> > > something else probably do know better and so should be left alone.
> > 
> > Regardless of that, I think that still the skb pointers would be changed
> > by this patch which would confuse the receiver of the SKB (device
> > driver), no? Has anyone verified that theory? :)
> 
> Maybe receivers made wrong assumptions about some headers being set or
> not set ?

Maybe. I haven't tested it, but I'm thinking that skb->data doesn't
point to the start of the data frame in this case, since we now call
eth_type_trans() which pulls the ethernet header. So if the device just
transmits skb->len starting from skb->data, it'll be wrong, no? That
seems a basic assumption though.

johannes