Function mesh_pick_bss

freebsd/net80211/ieee80211_scan_sta.c:1900–1982

* Pick an mbss network to join or find a channel * to use to start an mbss network. */

 * to use to start an mbss network.
 */
static int
mesh_pick_bss(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
{
	struct sta_table *st = ss->ss_priv;
	struct ieee80211_mesh_state *ms = vap->iv_mesh;
	struct sta_entry *selbs;
	struct ieee80211_channel *chan;

	KASSERT(vap->iv_opmode == IEEE80211_M_MBSS,
		("wrong opmode %u", vap->iv_opmode));

	if (st->st_newscan) {
		sta_update_notseen(st);
		st->st_newscan = 0;
	}
	if (ss->ss_flags & IEEE80211_SCAN_NOPICK) {
		/*
		 * Manual/background scan, don't select+join the
		 * bss, just return.  The scanning framework will
		 * handle notification that this has completed.
		 */
		ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
		return 1;
	}
	/*
	 * Automatic sequencing; look for a candidate and
	 * if found join the network.
	 */
	/* NB: unlocked read should be ok */
	if (TAILQ_FIRST(&st->st_entry) == NULL) {
		IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
			"%s: no scan candidate\n", __func__);
		if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
			return 0;
notfound:
		if (ms->ms_idlen != 0) {
			/*
			 * No existing mbss network to join and we have
			 * a meshid; start one up.  If no channel was
			 * specified, try to select a channel.
			 */
			if (vap->iv_des_chan == IEEE80211_CHAN_ANYC ||
			    IEEE80211_IS_CHAN_RADAR(vap->iv_des_chan)) {
				struct ieee80211com *ic = vap->iv_ic;

				/* XXX VHT */
				chan = adhoc_pick_channel(ss, 0);
				if (chan != NULL) {
					chan = ieee80211_ht_adjust_channel(ic,
					    chan, vap->iv_flags_ht);
					chan = ieee80211_vht_adjust_channel(ic,
					    chan, vap->iv_flags_vht);
					}
			} else
				chan = vap->iv_des_chan;
			if (chan != NULL) {
				ieee80211_create_ibss(vap, chan);
				return 1;