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

Michael S. Tsirkin
2010-01-27T09:47:42Z

On Wed, Jan 27, 2010 at 10:34:35AM +0100, Arnd Bergmann wrote:
> On Wednesday 27 January 2010, Michael S. Tsirkin wrote:
> > I am not sure I agree with this sentiment. The main issue being that
> > macvtap doesn't exist on all kernels :). macvlan also requires hardware
> > support, packet socket can work with any network card in promisc mode.
>
> To be clear, macvlan does not require hardware support, it will happily
> put cards into promiscous mode if they don't support multiple mac addresses.
>
> > I agree to that. People don't even seem to agree whether it's a raw
> > socket or a packet socket :) We need a better name for this option: what
> > it really does is rely on an external device to loopback a packet to us,
> > so how about -net loopback or -net extbridge?
>
> 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?

> If you really want to let qemu open the socket itself, -net socket,raw=eth0
> is probably closer to what you want than a new -net xxx option.
>
> Arnd

So again if implemented this probably should be
-net socket,raw,loopback=eth0 or -net socket,raw,extbridge=eth0
or some such, just to make it abundantly clear that you must not bind it
to a regular ethernet device.

--
MST