802.11 MBO - added reassoc_delay and reason code

Multi Band Operations (MBO) provide stations with additional information
about roaming requests. Reassociation delay avoids ping-pong between APs.
By default a delay of 30s is requested from the station.
MBO code 5 defines signal quality as a reason for roaming. This could be
enhanced in the future by responding with other dynamically defined
reasons to improve further how transitions are handled by stations.

- ubus: add reason code to bss_transition request (actually static only)
- ubus: add reassociation delay to let the client know how long it should stay at the new AP
  dereived from station block timeout.
- main: add config option for reassociation delay with 30s as default

Signed-off-by: Nils Hendrik Rottgardt <n.rottgardt@gmail.com>

Author: NilsRo

main.c

@@ -97,6 +97,7 @@ void usteer_init_defaults(void)
 	config.initial_connect_delay = 0;
 	config.remote_node_timeout = 10;
 	config.aggressiveness = 3;
+	config.reassociation_delay = 30;
 
 	config.steer_reject_timeout = 60000;
 

openwrt/usteer/files/etc/config/usteer

@@ -80,6 +80,9 @@ config usteer
 	# 4 = BSS-transition-request with disassociation imminent, timer and forced disassociation
 	#option aggressiveness 3
 
+	# Timeout (s in "1024ms") a station is requested to avoid reassociation after bss transition
+	#option reassociation_delay 30
+
 	# List of MACs (lower case) to set aggressiveness per station (ff:ff:ff:ff:ff,2)
 	#list aggressiveness_mac_list ''
 

ubus.c

@@ -689,6 +689,8 @@ int usteer_ubus_bss_transition_request(struct sta_info *si,
 	}
 	blobmsg_add_u8(&b, "abridged", abridged);
 	blobmsg_add_u32(&b, "validity_period", validity_period);
+	blobmsg_add_u32(&b, "mbo_reason", 5);
+	blobmsg_add_u32(&b, "reassoc_delay", config.reassociation_delay);
 
 	if (!target_node) {
 		/* Add all known neighbors if no specific target set */
@@ -721,6 +723,8 @@ int usteer_ubus_band_steering_request(struct sta_info *si,
 	}
 	blobmsg_add_u8(&b, "abridged", abridged);
 	blobmsg_add_u32(&b, "validity_period", validity_period);
+	blobmsg_add_u32(&b, "mbo_reason", 5);
+	blobmsg_add_u32(&b, "reassoc_delay", config.reassociation_delay);
 
 	c = blobmsg_open_array(&b, "neighbors");
 	for_each_local_node(node) {

usteer.h

@@ -180,6 +180,7 @@ struct usteer_config {
 	uint32_t aggressiveness;
 	struct blob_attr *aggressiveness_mac_list;
 	uint32_t aggressive_disassoc_timer;
+	uint32_t reassociation_delay;
 
 	int32_t min_snr;
 	uint32_t min_snr_kick_delay;