[libvirt] OpenVZ ethernet interface type

[Jean-Baptiste Rouault]

Hello,

I'd like to be able to add interfaces to OpenVZ guests like the following
vzctl command does : vzctl set 100 --netif_add eth0,00:11:22:33:44:55,tap0
Here, eth0 is the guest interface name, and tap0 the host interface name.

This is currently not supported by libvirt so I'd like to implement it.
In terms of domain XML I think it would be something like:
  <interface type='ethernet'>
    <mac address='00:11:22:33:44:55'/>
    <source dev='eth0'/>
    <target dev='tap0'/>
  </interface>

Currently the OpenVZ driver calls "vzctl set 100 --ipadd" when the interface 
type is "ethernet" and the ip address attribute isn't empty.
Does it seem ok to use --netif_add for ethernet interfaces when there is no ip 
defined ?

Regards,

Jean-Baptiste Rouault