Re: [Qemu-devel] [PATCH V5 6/9] net/colo-compare.c: Make colo-compare support vnet_hdr_len

[Jason Wang]

On 2017年05月26日 13:35, Jason Wang wrote:
> On 2017年05月25日 21:18, Zhang Chen wrote:
> > > > @@ -472,7 +474,10 @@ static void colo_compare_connection(void 
> > > > *opaque, void *user_data)
> > > >           }
> > > >             if (result) {
> > > > -            ret = compare_chr_send(&s->chr_out, pkt->data, 
> > > > pkt->size);
> > > > +            ret = compare_chr_send(s,
> > > > +                                   pkt->data,
> > > > +                                   pkt->size,
> > > > +                                   pkt->vnet_hdr_len);
> > >
> > > Why not check vnet_hdr support here?  And don't we need strip 
> > > vnet_hdr here? (Since the redirector on destination does not do this)
> >
> > If we create a normal qemu guest that use virtio-net-pci driver, the 
> > guest's send packet have the vnet_hdr,
> > qemu virtio-net-pci driver will strip vnet_hdr then send to external 
> > network. In COLO we just redirect
> > or mirror the packet, finally the packet will back to primary qemu 
> > virtio-net-pci driver, So we just send
> > the packet.
> >
> > Thanks
> > Zhang Chen 
>
> But you send vnet_hdr_len unconditionally, which mean colo-compare can 
> not work for redirector with vnet_hdr off now?
>
> Thanks

Btw, you may consider to update the COLO example in docs for the case 
that needs vnet hdr.

Thanks