UDP_TUNNEL_INNER_IPV4
if (tunnel_type & UDP_TUNNEL_INNER_IPV4) {
family = (tunnel_type & UDP_TUNNEL_INNER_IPV4) ? AF_INET : AF_INET6;
inner_family = (tunnel_type & UDP_TUNNEL_INNER_IPV4) ? AF_INET :
int family = (variant->tunnel_type & UDP_TUNNEL_INNER_IPV4) ? AF_INET :