node: keep track of roam-sources and roam-destinations

Keep track of STA journeys between multiple nodes. When a new STA is
reported from a foreign node, check whether this STA was previously
associated with a local node.

Vice versa, check upon association whether or not the STA was previously
associated with a foreign node.

Keep track of these roaming transactions using two new (local) fields of
the node struct.

Signed-off-by: David Bauer <mail@david-bauer.net>

main.c

@@ -96,6 +96,7 @@ void usteer_init_defaults(void)
 	config.remote_node_timeout = 10;
 
 	config.roam_kick_delay = 100;
+	config.roam_process_timeout = 5 * 1000;
 	config.roam_scan_tries = 3;
 	config.roam_scan_interval = 10 * 1000;
 	config.roam_trigger_interval = 60 * 1000;