2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License.
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
11 * You should have received a copy of the GNU General Public License
12 * along with this program; if not, write to the Free Software
13 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
15 * Copyright (C) 2020 embedd.ch
16 * Copyright (C) 2020 Felix Fietkau <nbd@nbd.name>
17 * Copyright (C) 2020 John Crispin <john@phrozen.org>
25 below_assoc_threshold(struct sta_info
*si_cur
, struct sta_info
*si_new
)
27 int n_assoc_cur
= si_cur
->node
->n_assoc
;
28 int n_assoc_new
= si_new
->node
->n_assoc
;
29 bool ref_5g
= si_cur
->node
->freq
> 4000;
30 bool node_5g
= si_new
->node
->freq
> 4000;
32 if (ref_5g
&& !node_5g
)
33 n_assoc_new
+= config
.band_steering_threshold
;
34 else if (!ref_5g
&& node_5g
)
35 n_assoc_cur
+= config
.band_steering_threshold
;
37 n_assoc_new
+= config
.load_balancing_threshold
;
39 return n_assoc_new
<= n_assoc_cur
;
43 better_signal_strength(struct sta_info
*si_cur
, struct sta_info
*si_new
)
45 const bool is_better
= si_new
->signal
- si_cur
->signal
46 > (int) config
.signal_diff_threshold
;
48 if (!config
.signal_diff_threshold
)
55 below_load_threshold(struct sta_info
*si
)
57 return si
->node
->n_assoc
>= config
.load_kick_min_clients
&&
58 si
->node
->load
> config
.load_kick_threshold
;
62 has_better_load(struct sta_info
*si_cur
, struct sta_info
*si_new
)
64 return !below_load_threshold(si_cur
) && below_load_threshold(si_new
);
68 below_max_assoc(struct sta_info
*si
)
70 struct usteer_node
*node
= si
->node
;
72 return !node
->max_assoc
|| node
->n_assoc
< node
->max_assoc
;
76 over_min_signal(struct sta_info
*si
)
78 if (config
.min_snr
&& si
->signal
< usteer_snr_to_signal(si
->node
, config
.min_snr
))
81 if (config
.roam_trigger_snr
&& si
->signal
< usteer_snr_to_signal(si
->node
, config
.roam_trigger_snr
))
88 is_better_candidate(struct sta_info
*si_cur
, struct sta_info
*si_new
)
92 if (!below_max_assoc(si_new
))
95 if (!over_min_signal(si_new
))
98 if (below_assoc_threshold(si_cur
, si_new
) &&
99 !below_assoc_threshold(si_new
, si_cur
))
100 reasons
|= (1 << UEV_SELECT_REASON_NUM_ASSOC
);
102 if (better_signal_strength(si_cur
, si_new
))
103 reasons
|= (1 << UEV_SELECT_REASON_SIGNAL
);
105 if (has_better_load(si_cur
, si_new
) &&
106 !has_better_load(si_cur
, si_new
))
107 reasons
|= (1 << UEV_SELECT_REASON_LOAD
);
112 static struct sta_info
*
113 find_better_candidate(struct sta_info
*si_ref
, struct uevent
*ev
, uint32_t required_criteria
, uint64_t max_age
)
116 struct sta
*sta
= si_ref
->sta
;
119 list_for_each_entry(si
, &sta
->nodes
, list
) {
123 if (current_time
- si
->seen
> config
.seen_policy_timeout
)
126 if (strcmp(si
->node
->ssid
, si_ref
->node
->ssid
) != 0)
129 if (max_age
&& max_age
< current_time
- si
->seen
)
132 reasons
= is_better_candidate(si_ref
, si
);
136 if (!(reasons
& required_criteria
))
141 ev
->select_reasons
= reasons
;
151 usteer_snr_to_signal(struct usteer_node
*node
, int snr
)
165 usteer_check_request(struct sta_info
*si
, enum usteer_event_type type
)
173 if (type
== EVENT_TYPE_AUTH
)
176 if (type
== EVENT_TYPE_ASSOC
) {
177 /* Check if assoc request has lower signal than min_signal.
178 * If this is the case, block assoc even when assoc steering is enabled.
180 * Otherwise, the client potentially ends up in a assoc - kick loop.
182 if (config
.min_snr
&& si
->signal
< usteer_snr_to_signal(si
->node
, config
.min_snr
)) {
183 ev
.reason
= UEV_REASON_LOW_SIGNAL
;
184 ev
.threshold
.cur
= si
->signal
;
185 ev
.threshold
.ref
= usteer_snr_to_signal(si
->node
, config
.min_snr
);
188 } else if (!config
.assoc_steering
) {
193 min_signal
= usteer_snr_to_signal(si
->node
, config
.min_connect_snr
);
194 if (si
->signal
< min_signal
) {
195 ev
.reason
= UEV_REASON_LOW_SIGNAL
;
196 ev
.threshold
.cur
= si
->signal
;
197 ev
.threshold
.ref
= min_signal
;
202 if (current_time
- si
->created
< config
.initial_connect_delay
) {
203 ev
.reason
= UEV_REASON_CONNECT_DELAY
;
204 ev
.threshold
.cur
= current_time
- si
->created
;
205 ev
.threshold
.ref
= config
.initial_connect_delay
;
210 if (!find_better_candidate(si
, &ev
, UEV_SELECT_REASON_ALL
, 0))
213 ev
.reason
= UEV_REASON_BETTER_CANDIDATE
;
214 ev
.node_cur
= si
->node
;
219 case EVENT_TYPE_PROBE
:
220 ev
.type
= UEV_PROBE_REQ_ACCEPT
;
222 case EVENT_TYPE_ASSOC
:
223 ev
.type
= UEV_ASSOC_REQ_ACCEPT
;
225 case EVENT_TYPE_AUTH
:
226 ev
.type
= UEV_AUTH_REQ_ACCEPT
;
235 if (!ret
&& si
->stats
[type
].blocked_cur
>= config
.max_retry_band
) {
236 ev
.reason
= UEV_REASON_RETRY_EXCEEDED
;
237 ev
.threshold
.cur
= si
->stats
[type
].blocked_cur
;
238 ev
.threshold
.ref
= config
.max_retry_band
;
246 is_more_kickable(struct sta_info
*si_cur
, struct sta_info
*si_new
)
251 if (si_new
->kick_count
> si_cur
->kick_count
)
254 return si_cur
->signal
> si_new
->signal
;
258 usteer_roam_set_state(struct sta_info
*si
, enum roam_trigger_state state
,
261 si
->roam_event
= current_time
;
263 if (si
->roam_state
== state
) {
264 if (si
->roam_state
== ROAM_TRIGGER_IDLE
) {
274 si
->roam_state
= state
;
279 usteer_roam_sm_start_scan(struct sta_info
*si
, struct uevent
*ev
)
281 /* Start scanning in case we are not timeout-constrained or timeout has expired */
282 if (!config
.roam_scan_timeout
||
283 current_time
> si
->roam_scan_timeout_start
+ config
.roam_scan_timeout
) {
284 usteer_roam_set_state(si
, ROAM_TRIGGER_SCAN
, ev
);
288 /* We are currently in scan timeout / cooldown.
289 * Check if we are in ROAM_TRIGGER_IDLE state. Enter this state if not.
291 if (si
->roam_state
== ROAM_TRIGGER_IDLE
)
294 /* Enter idle state */
295 usteer_roam_set_state(si
, ROAM_TRIGGER_IDLE
, ev
);
299 usteer_roam_sm_found_better_node(struct sta_info
*si
, struct uevent
*ev
, enum roam_trigger_state next_state
)
301 uint64_t max_age
= 2 * config
.roam_scan_interval
;
303 if (max_age
> current_time
- si
->roam_scan_start
)
304 max_age
= current_time
- si
->roam_scan_start
;
306 if (find_better_candidate(si
, ev
, (1 << UEV_SELECT_REASON_SIGNAL
), max_age
)) {
307 usteer_roam_set_state(si
, next_state
, ev
);
315 usteer_roam_trigger_sm(struct sta_info
*si
)
322 min_signal
= usteer_snr_to_signal(si
->node
, config
.roam_trigger_snr
);
324 switch (si
->roam_state
) {
325 case ROAM_TRIGGER_SCAN
:
326 if (!si
->roam_tries
) {
327 si
->roam_scan_start
= current_time
;
330 /* Check if we've found a better node regardless of the scan-interval */
331 if (usteer_roam_sm_found_better_node(si
, &ev
, ROAM_TRIGGER_SCAN_DONE
))
334 /* Only scan every scan-interval */
335 if (current_time
- si
->roam_event
< config
.roam_scan_interval
)
338 /* Check if no node was found within roam_scan_tries tries */
339 if (config
.roam_scan_tries
&& si
->roam_tries
>= config
.roam_scan_tries
) {
340 if (!config
.roam_scan_timeout
) {
341 /* Prepare to kick client */
342 usteer_roam_set_state(si
, ROAM_TRIGGER_WAIT_KICK
, &ev
);
344 /* Kick in scan timeout */
345 si
->roam_scan_timeout_start
= current_time
;
346 usteer_roam_set_state(si
, ROAM_TRIGGER_IDLE
, &ev
);
351 /* Send beacon-request to client */
352 usteer_ubus_trigger_client_scan(si
);
353 usteer_roam_sm_start_scan(si
, &ev
);
356 case ROAM_TRIGGER_IDLE
:
357 usteer_roam_sm_start_scan(si
, &ev
);
360 case ROAM_TRIGGER_SCAN_DONE
:
361 if (usteer_roam_sm_found_better_node(si
, &ev
, ROAM_TRIGGER_WAIT_KICK
))
364 /* Kick back to SCAN state if candidate expired */
365 usteer_roam_sm_start_scan(si
, &ev
);
368 case ROAM_TRIGGER_WAIT_KICK
:
369 if (si
->signal
> min_signal
)
372 usteer_roam_set_state(si
, ROAM_TRIGGER_NOTIFY_KICK
, &ev
);
373 usteer_ubus_notify_client_disassoc(si
);
375 case ROAM_TRIGGER_NOTIFY_KICK
:
376 if (current_time
- si
->roam_event
< config
.roam_kick_delay
* 100)
379 usteer_roam_set_state(si
, ROAM_TRIGGER_KICK
, &ev
);
381 case ROAM_TRIGGER_KICK
:
382 usteer_ubus_kick_client(si
);
383 usteer_roam_set_state(si
, ROAM_TRIGGER_IDLE
, &ev
);
391 usteer_local_node_roam_check(struct usteer_local_node
*ln
, struct uevent
*ev
)
396 if (config
.roam_scan_snr
)
397 min_signal
= config
.roam_scan_snr
;
398 else if (config
.roam_trigger_snr
)
399 min_signal
= config
.roam_trigger_snr
;
403 usteer_update_time();
404 min_signal
= usteer_snr_to_signal(&ln
->node
, min_signal
);
406 list_for_each_entry(si
, &ln
->node
.sta_info
, node_list
) {
407 if (si
->connected
!= STA_CONNECTED
|| si
->signal
>= min_signal
||
408 current_time
- si
->roam_kick
< config
.roam_trigger_interval
) {
409 usteer_roam_set_state(si
, ROAM_TRIGGER_IDLE
, ev
);
414 * If the state machine kicked a client, other clients should wait
415 * until the next turn
417 if (usteer_roam_trigger_sm(si
))
423 usteer_local_node_snr_kick(struct usteer_local_node
*ln
)
426 .node_local
= &ln
->node
,
434 min_signal
= usteer_snr_to_signal(&ln
->node
, config
.min_snr
);
435 ev
.threshold
.ref
= min_signal
;
437 list_for_each_entry(si
, &ln
->node
.sta_info
, node_list
) {
438 if (si
->connected
!= STA_CONNECTED
)
441 if (si
->signal
>= min_signal
)
446 ev
.type
= UEV_SIGNAL_KICK
;
447 ev
.threshold
.cur
= si
->signal
;
448 ev
.count
= si
->kick_count
;
451 usteer_ubus_kick_client(si
);
457 usteer_local_node_kick(struct usteer_local_node
*ln
)
459 struct usteer_node
*node
= &ln
->node
;
460 struct sta_info
*kick1
= NULL
, *kick2
= NULL
;
461 struct sta_info
*candidate
= NULL
;
464 .node_local
= &ln
->node
,
466 unsigned int min_count
= DIV_ROUND_UP(config
.load_kick_delay
, config
.local_sta_update
);
468 usteer_local_node_roam_check(ln
, &ev
);
469 usteer_local_node_snr_kick(ln
);
471 if (!config
.load_kick_enabled
|| !config
.load_kick_threshold
||
472 !config
.load_kick_delay
)
475 if (node
->load
< config
.load_kick_threshold
) {
476 if (!ln
->load_thr_count
)
479 ln
->load_thr_count
= 0;
480 ev
.type
= UEV_LOAD_KICK_RESET
;
481 ev
.threshold
.cur
= node
->load
;
482 ev
.threshold
.ref
= config
.load_kick_threshold
;
486 if (++ln
->load_thr_count
<= min_count
) {
487 if (ln
->load_thr_count
> 1)
490 ev
.type
= UEV_LOAD_KICK_TRIGGER
;
491 ev
.threshold
.cur
= node
->load
;
492 ev
.threshold
.ref
= config
.load_kick_threshold
;
496 ln
->load_thr_count
= 0;
497 if (node
->n_assoc
< config
.load_kick_min_clients
) {
498 ev
.type
= UEV_LOAD_KICK_MIN_CLIENTS
;
499 ev
.threshold
.cur
= node
->n_assoc
;
500 ev
.threshold
.ref
= config
.load_kick_min_clients
;
504 list_for_each_entry(si
, &ln
->node
.sta_info
, node_list
) {
505 struct sta_info
*tmp
;
507 if (si
->connected
!= STA_CONNECTED
)
510 if (is_more_kickable(kick1
, si
))
513 tmp
= find_better_candidate(si
, NULL
, (1 << UEV_SELECT_REASON_LOAD
), 0);
517 if (is_more_kickable(kick2
, si
)) {
524 ev
.type
= UEV_LOAD_KICK_NO_CLIENT
;
533 ev
.type
= UEV_LOAD_KICK_CLIENT
;
535 ev
.si_other
= candidate
;
536 ev
.count
= kick1
->kick_count
;
538 usteer_ubus_kick_client(kick1
);