* @get_iflink: Get the system interface index associated with the device that
* will be used to send packets (may be different than ifindex for tunnels).
* May be null if the device does not have an iflink.
* @get_iflink: Get the system interface index associated with the device that
* will be used to send packets (may be different than ifindex for tunnels).
* May be null if the device does not have an iflink.