1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * MLO link handling
4 *
5 * Copyright (C) 2022-2025 Intel Corporation
6 */
7 #include <linux/slab.h>
8 #include <linux/kernel.h>
9 #include <net/mac80211.h>
10 #include "ieee80211_i.h"
11 #include "driver-ops.h"
12 #include "key.h"
13 #include "debugfs_netdev.h"
14
ieee80211_update_apvlan_links(struct ieee80211_sub_if_data * sdata)15 static void ieee80211_update_apvlan_links(struct ieee80211_sub_if_data *sdata)
16 {
17 unsigned long rem = ~sdata->vif.valid_links &
18 GENMASK(IEEE80211_MLD_MAX_NUM_LINKS - 1, 0);
19 struct ieee80211_local *local = sdata->local;
20 unsigned long add = sdata->vif.valid_links;
21 struct wiphy *wiphy = local->hw.wiphy;
22 struct ieee80211_sub_if_data *vlan;
23 struct ieee80211_link_data *link;
24 struct sta_info *sta;
25
26 list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
27 int link_id;
28
29 if (vlan->wdev.use_4addr) {
30 sta = wiphy_dereference(wiphy,
31 vlan->u.vlan.sta);
32 if (sta)
33 add = add & sta->sta.valid_links;
34 }
35
36 if (add == vlan->vif.valid_links)
37 continue;
38
39 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
40 vlan->wdev.valid_links |= BIT(link_id);
41 ether_addr_copy(vlan->wdev.links[link_id].addr,
42 sdata->wdev.links[link_id].addr);
43 }
44
45 for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
46 vlan->wdev.valid_links &= ~BIT(link_id);
47 eth_zero_addr(vlan->wdev.links[link_id].addr);
48 }
49
50 ieee80211_vif_set_links(vlan, add, 0);
51
52 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
53 link = sdata_dereference(vlan->link[link_id], vlan);
54 ieee80211_link_vlan_copy_chanctx(link);
55 }
56 }
57 }
58
ieee80211_apvlan_link_setup(struct ieee80211_sub_if_data * sdata)59 void ieee80211_apvlan_link_setup(struct ieee80211_sub_if_data *sdata)
60 {
61 struct ieee80211_sub_if_data *ap_bss = container_of(sdata->bss,
62 struct ieee80211_sub_if_data, u.ap);
63 u16 new_links = ap_bss->vif.valid_links;
64 unsigned long add;
65 int link_id;
66
67 if (!ap_bss->vif.valid_links)
68 return;
69
70 add = new_links;
71 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
72 sdata->wdev.valid_links |= BIT(link_id);
73 ether_addr_copy(sdata->wdev.links[link_id].addr,
74 ap_bss->wdev.links[link_id].addr);
75 }
76
77 ieee80211_vif_set_links(sdata, new_links, 0);
78 }
79
ieee80211_apvlan_link_clear(struct ieee80211_sub_if_data * sdata)80 void ieee80211_apvlan_link_clear(struct ieee80211_sub_if_data *sdata)
81 {
82 if (!sdata->wdev.valid_links)
83 return;
84
85 sdata->wdev.valid_links = 0;
86 ieee80211_vif_clear_links(sdata);
87 }
88
ieee80211_link_setup(struct ieee80211_link_data * link)89 void ieee80211_link_setup(struct ieee80211_link_data *link)
90 {
91 if (link->sdata->vif.type == NL80211_IFTYPE_STATION)
92 ieee80211_mgd_setup_link(link);
93 }
94
ieee80211_link_init(struct ieee80211_sub_if_data * sdata,int link_id,struct ieee80211_link_data * link,struct ieee80211_bss_conf * link_conf)95 void ieee80211_link_init(struct ieee80211_sub_if_data *sdata,
96 int link_id,
97 struct ieee80211_link_data *link,
98 struct ieee80211_bss_conf *link_conf)
99 {
100 bool deflink = link_id < 0;
101
102 if (link_id < 0)
103 link_id = 0;
104
105 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
106 struct ieee80211_sub_if_data *ap_bss;
107 struct ieee80211_bss_conf *ap_bss_conf;
108
109 ap_bss = container_of(sdata->bss,
110 struct ieee80211_sub_if_data, u.ap);
111
112 if (deflink)
113 ap_bss_conf = &ap_bss->vif.bss_conf;
114 else
115 ap_bss_conf = sdata_dereference(ap_bss->vif.link_conf[link_id],
116 ap_bss);
117
118 memcpy(link_conf, ap_bss_conf, sizeof(*link_conf));
119 }
120
121 link->sdata = sdata;
122 link->link_id = link_id;
123 link->conf = link_conf;
124 link_conf->link_id = link_id;
125 link_conf->vif = &sdata->vif;
126 link->ap_power_level = IEEE80211_UNSET_POWER_LEVEL;
127 link->user_power_level = sdata->local->user_power_level;
128 link_conf->txpower = INT_MIN;
129
130 wiphy_work_init(&link->csa.finalize_work,
131 ieee80211_csa_finalize_work);
132 wiphy_work_init(&link->color_change_finalize_work,
133 ieee80211_color_change_finalize_work);
134 wiphy_delayed_work_init(&link->color_collision_detect_work,
135 ieee80211_color_collision_detection_work);
136 wiphy_hrtimer_work_init(&link->dfs_cac_timer_work,
137 ieee80211_dfs_cac_timer_work);
138
139 if (!deflink) {
140 switch (sdata->vif.type) {
141 case NL80211_IFTYPE_AP:
142 case NL80211_IFTYPE_AP_VLAN:
143 ether_addr_copy(link_conf->addr,
144 sdata->wdev.links[link_id].addr);
145 link_conf->bssid = link_conf->addr;
146 WARN_ON(!(sdata->wdev.valid_links & BIT(link_id)));
147 break;
148 case NL80211_IFTYPE_STATION:
149 /* station sets the bssid in ieee80211_mgd_setup_link */
150 break;
151 default:
152 WARN_ON(1);
153 }
154
155 ieee80211_link_debugfs_add(link);
156 }
157
158 rcu_assign_pointer(sdata->vif.link_conf[link_id], link_conf);
159 rcu_assign_pointer(sdata->link[link_id], link);
160 }
161
ieee80211_link_stop(struct ieee80211_link_data * link)162 void ieee80211_link_stop(struct ieee80211_link_data *link)
163 {
164 if (link->sdata->vif.type == NL80211_IFTYPE_STATION)
165 ieee80211_mgd_stop_link(link);
166
167 wiphy_delayed_work_cancel(link->sdata->local->hw.wiphy,
168 &link->color_collision_detect_work);
169 wiphy_work_cancel(link->sdata->local->hw.wiphy,
170 &link->color_change_finalize_work);
171 wiphy_work_cancel(link->sdata->local->hw.wiphy,
172 &link->csa.finalize_work);
173
174 if (link->sdata->wdev.links[link->link_id].cac_started) {
175 wiphy_hrtimer_work_cancel(link->sdata->local->hw.wiphy,
176 &link->dfs_cac_timer_work);
177 cfg80211_cac_event(link->sdata->dev,
178 &link->conf->chanreq.oper,
179 NL80211_RADAR_CAC_ABORTED,
180 GFP_KERNEL, link->link_id);
181 }
182
183 ieee80211_link_release_channel(link);
184 }
185
186 struct link_container {
187 struct ieee80211_link_data data;
188 struct ieee80211_bss_conf conf;
189 };
190
ieee80211_tear_down_links(struct ieee80211_sub_if_data * sdata,struct link_container ** links,u16 mask)191 static void ieee80211_tear_down_links(struct ieee80211_sub_if_data *sdata,
192 struct link_container **links, u16 mask)
193 {
194 struct ieee80211_link_data *link;
195 LIST_HEAD(keys);
196 unsigned int link_id;
197
198 for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++) {
199 if (!(mask & BIT(link_id)))
200 continue;
201 link = &links[link_id]->data;
202 if (link_id == 0 && !link)
203 link = &sdata->deflink;
204 if (WARN_ON(!link))
205 continue;
206 ieee80211_remove_link_keys(link, &keys);
207 ieee80211_link_debugfs_remove(link);
208 ieee80211_link_stop(link);
209 }
210
211 synchronize_rcu();
212
213 ieee80211_free_key_list(sdata->local, &keys);
214 }
215
ieee80211_free_links(struct ieee80211_sub_if_data * sdata,struct link_container ** links)216 static void ieee80211_free_links(struct ieee80211_sub_if_data *sdata,
217 struct link_container **links)
218 {
219 unsigned int link_id;
220
221 for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++)
222 kfree(links[link_id]);
223 }
224
ieee80211_check_dup_link_addrs(struct ieee80211_sub_if_data * sdata)225 static int ieee80211_check_dup_link_addrs(struct ieee80211_sub_if_data *sdata)
226 {
227 unsigned int i, j;
228
229 for (i = 0; i < IEEE80211_MLD_MAX_NUM_LINKS; i++) {
230 struct ieee80211_link_data *link1;
231
232 link1 = sdata_dereference(sdata->link[i], sdata);
233 if (!link1)
234 continue;
235 for (j = i + 1; j < IEEE80211_MLD_MAX_NUM_LINKS; j++) {
236 struct ieee80211_link_data *link2;
237
238 link2 = sdata_dereference(sdata->link[j], sdata);
239 if (!link2)
240 continue;
241
242 if (ether_addr_equal(link1->conf->addr,
243 link2->conf->addr))
244 return -EALREADY;
245 }
246 }
247
248 return 0;
249 }
250
ieee80211_set_vif_links_bitmaps(struct ieee80211_sub_if_data * sdata,u16 valid_links,u16 dormant_links)251 static void ieee80211_set_vif_links_bitmaps(struct ieee80211_sub_if_data *sdata,
252 u16 valid_links, u16 dormant_links)
253 {
254 sdata->vif.valid_links = valid_links;
255 sdata->vif.dormant_links = dormant_links;
256
257 if (!valid_links ||
258 WARN((~valid_links & dormant_links) ||
259 !(valid_links & ~dormant_links),
260 "Invalid links: valid=0x%x, dormant=0x%x",
261 valid_links, dormant_links)) {
262 sdata->vif.active_links = 0;
263 sdata->vif.dormant_links = 0;
264 return;
265 }
266
267 switch (sdata->vif.type) {
268 case NL80211_IFTYPE_AP:
269 case NL80211_IFTYPE_AP_VLAN:
270 /* in an AP all links are always active */
271 sdata->vif.active_links = valid_links;
272
273 /* AP links are not expected to be disabled */
274 WARN_ON(dormant_links);
275 break;
276 case NL80211_IFTYPE_STATION:
277 if (sdata->vif.active_links)
278 break;
279 sdata->vif.active_links = valid_links & ~dormant_links;
280 WARN_ON(hweight16(sdata->vif.active_links) > 1);
281 break;
282 default:
283 WARN_ON(1);
284 }
285 }
286
ieee80211_vif_update_links(struct ieee80211_sub_if_data * sdata,struct link_container ** to_free,u16 new_links,u16 dormant_links)287 static int ieee80211_vif_update_links(struct ieee80211_sub_if_data *sdata,
288 struct link_container **to_free,
289 u16 new_links, u16 dormant_links)
290 {
291 u16 old_links = sdata->vif.valid_links;
292 u16 old_active = sdata->vif.active_links;
293 unsigned long add = new_links & ~old_links;
294 unsigned long rem = old_links & ~new_links;
295 unsigned int link_id;
296 int ret;
297 struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS] = {}, *link;
298 struct ieee80211_bss_conf *old[IEEE80211_MLD_MAX_NUM_LINKS];
299 struct ieee80211_link_data *old_data[IEEE80211_MLD_MAX_NUM_LINKS];
300 bool use_deflink = old_links == 0; /* set for error case */
301 bool non_sta = sdata->vif.type != NL80211_IFTYPE_STATION;
302
303 lockdep_assert_wiphy(sdata->local->hw.wiphy);
304
305 memset(to_free, 0, sizeof(links));
306
307 if (old_links == new_links && dormant_links == sdata->vif.dormant_links)
308 return 0;
309
310 /* if there were no old links, need to clear the pointers to deflink */
311 if (!old_links)
312 rem |= BIT(0);
313
314 /* allocate new link structures first */
315 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
316 link = kzalloc_obj(*link);
317 if (!link) {
318 ret = -ENOMEM;
319 goto free;
320 }
321 links[link_id] = link;
322 }
323
324 /* keep track of the old pointers for the driver */
325 BUILD_BUG_ON(sizeof(old) != sizeof(sdata->vif.link_conf));
326 memcpy(old, sdata->vif.link_conf, sizeof(old));
327 /* and for us in error cases */
328 BUILD_BUG_ON(sizeof(old_data) != sizeof(sdata->link));
329 memcpy(old_data, sdata->link, sizeof(old_data));
330
331 /* grab old links to free later */
332 for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
333 if (rcu_access_pointer(sdata->link[link_id]) != &sdata->deflink) {
334 /*
335 * we must have allocated the data through this path so
336 * we know we can free both at the same time
337 */
338 to_free[link_id] = container_of(rcu_access_pointer(sdata->link[link_id]),
339 typeof(*links[link_id]),
340 data);
341 }
342
343 RCU_INIT_POINTER(sdata->link[link_id], NULL);
344 RCU_INIT_POINTER(sdata->vif.link_conf[link_id], NULL);
345 }
346
347 if (!old_links)
348 ieee80211_debugfs_recreate_netdev(sdata, true);
349
350 /* link them into data structures */
351 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
352 WARN_ON(!use_deflink &&
353 rcu_access_pointer(sdata->link[link_id]) == &sdata->deflink);
354
355 link = links[link_id];
356 ieee80211_link_init(sdata, link_id, &link->data, &link->conf);
357 ieee80211_link_setup(&link->data);
358 ieee80211_set_wmm_default(&link->data, true, non_sta);
359 }
360
361 if (new_links == 0)
362 ieee80211_link_init(sdata, -1, &sdata->deflink,
363 &sdata->vif.bss_conf);
364
365 ret = ieee80211_check_dup_link_addrs(sdata);
366 if (!ret) {
367 /* for keys we will not be able to undo this */
368 ieee80211_tear_down_links(sdata, to_free, rem);
369
370 ieee80211_set_vif_links_bitmaps(sdata, new_links, dormant_links);
371
372 /* tell the driver */
373 if (sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
374 ret = drv_change_vif_links(sdata->local, sdata,
375 old_links & old_active,
376 new_links & sdata->vif.active_links,
377 old);
378 if (!new_links)
379 ieee80211_debugfs_recreate_netdev(sdata, false);
380
381 if (sdata->vif.type == NL80211_IFTYPE_AP)
382 ieee80211_update_apvlan_links(sdata);
383 }
384
385 /*
386 * Ignore errors if we are only removing links as removal should
387 * always succeed
388 */
389 if (!new_links)
390 ret = 0;
391
392 if (ret) {
393 /* restore config */
394 memcpy(sdata->link, old_data, sizeof(old_data));
395 memcpy(sdata->vif.link_conf, old, sizeof(old));
396 ieee80211_set_vif_links_bitmaps(sdata, old_links, dormant_links);
397 /* and free (only) the newly allocated links */
398 memset(to_free, 0, sizeof(links));
399 goto free;
400 }
401
402 /* use deflink/bss_conf again if and only if there are no more links */
403 use_deflink = new_links == 0;
404
405 goto deinit;
406 free:
407 /* if we failed during allocation, only free all */
408 for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++) {
409 kfree(links[link_id]);
410 links[link_id] = NULL;
411 }
412 deinit:
413 if (use_deflink)
414 ieee80211_link_init(sdata, -1, &sdata->deflink,
415 &sdata->vif.bss_conf);
416 return ret;
417 }
418
ieee80211_vif_set_links(struct ieee80211_sub_if_data * sdata,u16 new_links,u16 dormant_links)419 int ieee80211_vif_set_links(struct ieee80211_sub_if_data *sdata,
420 u16 new_links, u16 dormant_links)
421 {
422 struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS];
423 int ret;
424
425 ret = ieee80211_vif_update_links(sdata, links, new_links,
426 dormant_links);
427 ieee80211_free_links(sdata, links);
428
429 return ret;
430 }
431
_ieee80211_set_active_links(struct ieee80211_sub_if_data * sdata,u16 active_links)432 static int _ieee80211_set_active_links(struct ieee80211_sub_if_data *sdata,
433 u16 active_links)
434 {
435 struct ieee80211_bss_conf *link_confs[IEEE80211_MLD_MAX_NUM_LINKS];
436 struct ieee80211_local *local = sdata->local;
437 u16 old_active = sdata->vif.active_links;
438 unsigned long rem = old_active & ~active_links;
439 unsigned long add = active_links & ~old_active;
440 struct sta_info *sta;
441 unsigned int link_id;
442 int ret, i;
443
444 if (!ieee80211_sdata_running(sdata))
445 return -ENETDOWN;
446
447 if (sdata->vif.type != NL80211_IFTYPE_STATION)
448 return -EINVAL;
449
450 if (active_links & ~ieee80211_vif_usable_links(&sdata->vif))
451 return -EINVAL;
452
453 /* nothing to do */
454 if (old_active == active_links)
455 return 0;
456
457 for (i = 0; i < IEEE80211_MLD_MAX_NUM_LINKS; i++)
458 link_confs[i] = sdata_dereference(sdata->vif.link_conf[i],
459 sdata);
460
461 if (add) {
462 sdata->vif.active_links |= active_links;
463 ret = drv_change_vif_links(local, sdata,
464 old_active,
465 sdata->vif.active_links,
466 link_confs);
467 if (ret) {
468 sdata->vif.active_links = old_active;
469 return ret;
470 }
471 }
472
473 for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
474 struct ieee80211_link_data *link;
475
476 link = sdata_dereference(sdata->link[link_id], sdata);
477
478 ieee80211_teardown_tdls_peers(link);
479
480 __ieee80211_link_release_channel(link, true);
481
482 /*
483 * If CSA is (still) active while the link is deactivated,
484 * just schedule the channel switch work for the time we
485 * had previously calculated, and we'll take the process
486 * from there.
487 */
488 if (link->conf->csa_active)
489 wiphy_hrtimer_work_queue(local->hw.wiphy,
490 &link->u.mgd.csa.switch_work,
491 link->u.mgd.csa.time -
492 ktime_get_boottime());
493 }
494
495 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
496 struct ieee80211_link_data *link;
497
498 link = sdata_dereference(sdata->link[link_id], sdata);
499
500 /*
501 * This call really should not fail. Unfortunately, it appears
502 * that this may happen occasionally with some drivers. Should
503 * it happen, we are stuck in a bad place as going backwards is
504 * not really feasible.
505 *
506 * So lets just tell link_use_channel that it must not fail to
507 * assign the channel context (from mac80211's perspective) and
508 * assume the driver is going to trigger a recovery flow if it
509 * had a failure.
510 * That really is not great nor guaranteed to work. But at least
511 * the internal mac80211 state remains consistent and there is
512 * a chance that we can recover.
513 */
514 ret = _ieee80211_link_use_channel(link,
515 &link->conf->chanreq,
516 IEEE80211_CHANCTX_SHARED,
517 true);
518 WARN_ON_ONCE(ret);
519
520 /*
521 * inform about the link info changed parameters after all
522 * stations are also added
523 */
524 }
525
526 list_for_each_entry(sta, &local->sta_list, list) {
527 if (sdata != sta->sdata)
528 continue;
529
530 /* this is very temporary, but do it anyway */
531 __ieee80211_sta_recalc_aggregates(sta,
532 old_active | active_links);
533
534 ret = drv_change_sta_links(local, sdata, &sta->sta,
535 old_active,
536 old_active | active_links);
537 WARN_ON_ONCE(ret);
538 }
539
540 ret = ieee80211_key_switch_links(sdata, rem, add);
541 WARN_ON_ONCE(ret);
542
543 list_for_each_entry(sta, &local->sta_list, list) {
544 if (sdata != sta->sdata)
545 continue;
546
547 __ieee80211_sta_recalc_aggregates(sta, active_links);
548
549 ret = drv_change_sta_links(local, sdata, &sta->sta,
550 old_active | active_links,
551 active_links);
552 WARN_ON_ONCE(ret);
553
554 /*
555 * Do it again, just in case - the driver might very
556 * well have called ieee80211_sta_recalc_aggregates()
557 * from there when filling in the new links, which
558 * would set it wrong since the vif's active links are
559 * not switched yet...
560 */
561 __ieee80211_sta_recalc_aggregates(sta, active_links);
562 }
563
564 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
565 struct ieee80211_link_data *link;
566
567 link = sdata_dereference(sdata->link[link_id], sdata);
568
569 ieee80211_mgd_set_link_qos_params(link);
570 ieee80211_link_info_change_notify(sdata, link,
571 BSS_CHANGED_ERP_CTS_PROT |
572 BSS_CHANGED_ERP_PREAMBLE |
573 BSS_CHANGED_ERP_SLOT |
574 BSS_CHANGED_HT |
575 BSS_CHANGED_BASIC_RATES |
576 BSS_CHANGED_BSSID |
577 BSS_CHANGED_CQM |
578 BSS_CHANGED_QOS |
579 BSS_CHANGED_TXPOWER |
580 BSS_CHANGED_BANDWIDTH |
581 BSS_CHANGED_TWT |
582 BSS_CHANGED_HE_OBSS_PD |
583 BSS_CHANGED_HE_BSS_COLOR);
584 }
585
586 old_active = sdata->vif.active_links;
587 sdata->vif.active_links = active_links;
588
589 if (rem) {
590 ret = drv_change_vif_links(local, sdata, old_active,
591 active_links, link_confs);
592 WARN_ON_ONCE(ret);
593 }
594
595 return 0;
596 }
597
ieee80211_set_active_links(struct ieee80211_vif * vif,u16 active_links)598 int ieee80211_set_active_links(struct ieee80211_vif *vif, u16 active_links)
599 {
600 struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
601 struct ieee80211_local *local = sdata->local;
602 u16 old_active;
603 int ret;
604
605 lockdep_assert_wiphy(local->hw.wiphy);
606
607 if (WARN_ON(!active_links))
608 return -EINVAL;
609
610 old_active = sdata->vif.active_links;
611 if (old_active == active_links)
612 return 0;
613
614 if (!drv_can_activate_links(local, sdata, active_links))
615 return -EINVAL;
616
617 if (old_active & active_links) {
618 /*
619 * if there's at least one link that stays active across
620 * the change then switch to it (to those) first, and
621 * then enable the additional links
622 */
623 ret = _ieee80211_set_active_links(sdata,
624 old_active & active_links);
625 if (!ret)
626 ret = _ieee80211_set_active_links(sdata, active_links);
627 } else {
628 /* otherwise switch directly */
629 ret = _ieee80211_set_active_links(sdata, active_links);
630 }
631
632 return ret;
633 }
634 EXPORT_SYMBOL_GPL(ieee80211_set_active_links);
635
ieee80211_set_active_links_async(struct ieee80211_vif * vif,u16 active_links)636 void ieee80211_set_active_links_async(struct ieee80211_vif *vif,
637 u16 active_links)
638 {
639 struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
640
641 if (WARN_ON(!active_links))
642 return;
643
644 if (!ieee80211_sdata_running(sdata))
645 return;
646
647 if (sdata->vif.type != NL80211_IFTYPE_STATION)
648 return;
649
650 if (active_links & ~ieee80211_vif_usable_links(&sdata->vif))
651 return;
652
653 /* nothing to do */
654 if (sdata->vif.active_links == active_links)
655 return;
656
657 sdata->desired_active_links = active_links;
658 wiphy_work_queue(sdata->local->hw.wiphy, &sdata->activate_links_work);
659 }
660 EXPORT_SYMBOL_GPL(ieee80211_set_active_links_async);
661