Re: [PATCH 0/2] Disable forwarding of LRO skbs

[Kieran Mansley <kmansley@solarflare.com>]

On Thu, 2008-05-01 at 19:12 +0800, Herbert Xu wrote:
> On Thu, May 01, 2008 at 12:08:48PM +0100, Kieran Mansley wrote:
> >
> > Yes, everything works fine in that case.  It's only when LRO packets are
> > forwarded to another physical interface that things go wrong.  
> 
> Now this is definitely broken because it fiddles with TCP packets
> in the middle, but still it should *work* in as much as making the
> packet go out.  Well except that you need to fix up the checksum
> so that it only contains the pseudo-header on output.  That's
> probably what you need to address if we failed in avoiding LRO
> on forwarded traffic.

If I remember rightly it also gets upset when it comes to split the
packet because the frag_list is already in use; it expects this not to
be the case for GSO but it's valid for an LRO packet to do this I think.
I don't think there's anything fundamentally difficult here, it's just
that the code has never been written to cope.

Kieran