core-agent-linux/network/udev-qubes-network.rules

# old udev has ENV{ID_NET_DRIVER}
SUBSYSTEMS=="xen", KERNEL=="eth*", ACTION=="add", ENV{ID_NET_DRIVER}=="vif", RUN+="/usr/lib/qubes/setup-ip"
SUBSYSTEMS=="net", KERNEL=="eth*", ACTION=="remove", ENV{ID_NET_DRIVER}=="vif", RUN+="/usr/lib/qubes/setup-ip"
# new udev has DRIVERS
SUBSYSTEMS=="xen", KERNEL=="eth*", ACTION=="add", DRIVERS=="vif", RUN+="/usr/lib/qubes/setup-ip"