do_bridgeflag
do_bridgeflag(s, val, IFBIF_DISCOVER, 1);
do_bridgeflag(s, val, IFBIF_DISCOVER, 0);
do_bridgeflag(s, val, IFBIF_LEARNING, 1);
do_bridgeflag(s, val, IFBIF_LEARNING, 0);
do_bridgeflag(s, val, IFBIF_STP, 1);
do_bridgeflag(s, val, IFBIF_STP, 0);