From: Stephen Hemminger <stephen@networkplumber.org>
To: Michal Kubecek <mkubecek@suse.cz>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
netdev@vger.kernel.org, netfilter-devel@vger.kernel.org
Subject: Re: Can we rely on ethernet header padding?
Date: Tue, 19 Mar 2013 14:25:53 -0700 [thread overview]
Message-ID: <20130319142553.3e08e7b9@nehalam.linuxnetplumber.net> (raw)
In-Reply-To: <20130319154806.GB18218@unicorn.suse.cz>
On Tue, 19 Mar 2013 16:48:06 +0100
Michal Kubecek <mkubecek@suse.cz> wrote:
> On Tue, Mar 19, 2013 at 08:21:35AM -0700, Eric Dumazet wrote:
> >
> > Normally a driver has NET_SKB_PAD bytes of headroom before the ethernet
> > header, so the bridge code is safe only if all drivers use this
> > NET_SKB_PAD padding on receive side. And they really should for
> > performance reasons.
> >
> > Better not touch bridge code to catch offending drivers
>
> That makes sense. Thank you for your reply.
>
My view is that the bridge code must check before assuming headroom.
But because of that, it means a packet copy would be necessary for cases
where packets arrive without enough headroom.
next prev parent reply other threads:[~2013-03-19 21:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-19 15:05 Can we rely on ethernet header padding? Michal Kubecek
2013-03-19 15:21 ` Eric Dumazet
2013-03-19 15:48 ` Michal Kubecek
2013-03-19 21:25 ` Stephen Hemminger [this message]
2013-03-20 9:54 ` Michal Kubecek
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