The farp plugin fakes ARP responses for requests to a virtual IP address assigned to a peer.
To enable the plugin, add
--enable-farpto the ./configure options.
It is available since 4.4.0.
With the plugin enabled the IKEv2 daemon responds to ARP requests for virtual IP addresses that were handed out to clients with its own MAC address.
In combination with the dhcp plugin this plugin lets a road-warrior act as a client on the local LAN of the responder.