NG_SOURCE_DRIVER_IFQ_MAXLEN
if (ifp->if_snd.ifq_maxlen < NG_SOURCE_DRIVER_IFQ_MAXLEN) {
ifp->if_snd.ifq_maxlen, NG_SOURCE_DRIVER_IFQ_MAXLEN);
ifq_set_maxlen(&ifp->if_snd, NG_SOURCE_DRIVER_IFQ_MAXLEN);