Re: [PATCH qemu-kvm] Add raw(af_packet) network backend to qemu

Jens Osterkamp
2010-01-28T16:53:40Z

On Thursday 28 January 2010, Arnd Bergmann wrote:
> On Wednesday 27 January 2010, Sridhar Samudrala wrote:
> > On Wed, 2010-01-27 at 22:39 +0100, Arnd Bergmann wrote:
> > > On Wednesday 27 January 2010, Anthony Liguori wrote:
> > > > >> I think -net socket,fd should just be (trivially) extended to work
> > > > >> with raw sockets out of the box, with no support for opening it.
> > > > >> Then you can have libvirt or some wrapper open a raw socket and a
> > > > >> private namespace and just pass it down.
> > > > >
> > > > > That'd work. Anthony?
> > > >
> > > > The fundamental problem that I have with all of this is that we
> > > > should not be introducing new network backends that are based around
> > > > something only a developer is going to understand. If I'm a user and
> > > > I want to use an external switch in VEPA mode, how in the world am I
> > > > going to know that I'm supposed to use the -net raw backend or the
> > > > -net socket backend? It might as well be the -net butterflies
> > > > backend as far as a user is concerned.
> > >
> > > My point is that we already have -net socket,fd and any user that
> > > passes an fd into that already knows what he wants to do with it.
> > > Making it work with raw sockets is just a natural extension to this,
> > > which works on all kernels and (with separate namespaces) is reasonably
> > > secure.
> >
> > Didn't realize that -net socket is already there and supports TCP and
> > UDP sockets. I will look into extending -net socket to support AF_PACKET
> > SOCK_RAW type sockets.
>
> Actually, Jens had a patch doing this in early 2009 already but we
> decided to not send that one out at the time after Or had sent his
> version of the raw socket interface, which was a superset. Maybe Jens
> can post his patch again if that still applies?

It's been a while since I last looked at it. I think it will need a bitt
massaging before it will apply again.

Jens