ipw_stop
void ipw_stop(struct ifnet *, int);
ipw_stop(ifp, 1);
ipw_stop(ifp, 1);
ipw_stop(ifp, 1);
ipw_stop(ifp, 0);
fail1: ipw_stop(ifp, 0);
ipw_stop(ifp, 0);
ipw_stop(&ic->ic_if, 1);