Current FreeBSD netback names the interface with xnb<device unit>, but
this is not suitable for usage with the Xen toolstack, which expects
something similar to <prefix><domid><handle>. In order to solve this,
change the netback naming convention to use xnb<domid>.<handle>.
Sponsored by: Citrix Systems R&D
dev/xen/netback/netback.c:
- Change netback to use the nomenclature stated above.