NC_NOPROTO
if (strcmp(net->nc_proto, NC_NOPROTO) != 0)
strcmp(net->nc_proto, NC_NOPROTO) == 0 &&
knc.knc_proto = NC_NOPROTO;
{ NC_TPI_CLTS, NC_LOOPBACK, NC_NOPROTO, NODEV },
{ NC_TPI_COTS_ORD, NC_LOOPBACK, NC_NOPROTO, NODEV },