are at the end of the node queue. Change the reference-counting
discipline: ni->ni_refcnt indicates how many times net80211 has
granted ni to the driver. Every node in the table with ni_refcnt=0
is eligible to be garbage-collected. The mere presence of a node
in the table does not any longer indicate its auth/assoc state;
nodes have a ni_state variable, now. A sysctl,
net.link.ieee80211.maxnodecache, controls the maximum LRU cache
size.
While I am here, patch ieee80211_find_node_for_beacon to do a "best
match" by bssid/ssid/channel, not a "perfect match." This keeps
net80211 from caching duplicate nodes in the table.