TUN_IFHEAD
} else if (tp->tun_flags & TUN_IFHEAD) {
tp->tun_flags &= ~TUN_IFHEAD;
tp->tun_flags |= TUN_IFHEAD;
tp->tun_flags &= ~TUN_IFHEAD;
*(int *)data = (tp->tun_flags & TUN_IFHEAD);
} else if (tp->tun_flags & TUN_IFHEAD) {