rtsock_prepare_route_message
rtsock_prepare_route_message(rtm, cmd, dst, mask, gw);
rtsock_prepare_route_message(rtm, RTM_GET, NULL,
rtsock_prepare_route_message(rtm, RTM_GET, (struct sockaddr *)&c->addr4,
rtsock_prepare_route_message(rtm, cmd, dst, NULL, gw);