TUN_RWAIT
if (sc->tun_flags & TUN_RWAIT) {
sc->tun_flags &= ~TUN_RWAIT;
if (sc->tun_flags & TUN_RWAIT) {
sc->tun_flags &= ~TUN_RWAIT;
sc->tun_flags &= ~TUN_RWAIT;
sc->tun_flags |= TUN_RWAIT;