xref: /linux/net/mac80211/link.c (revision cf85f810f911234a06a4ef2439e8694b93b717fc)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * MLO link handling
4  *
5  * Copyright (C) 2022-2026 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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 long sta_rem = rem;
296 	unsigned int link_id;
297 	int ret;
298 	struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS] = {}, *link;
299 	struct ieee80211_bss_conf *old[IEEE80211_MLD_MAX_NUM_LINKS];
300 	struct ieee80211_link_data *old_data[IEEE80211_MLD_MAX_NUM_LINKS];
301 	bool use_deflink = old_links == 0; /* set for error case */
302 	bool non_sta = sdata->vif.type != NL80211_IFTYPE_STATION;
303 	struct sta_info *sta;
304 
305 	lockdep_assert_wiphy(sdata->local->hw.wiphy);
306 
307 	memset(to_free, 0, sizeof(links));
308 
309 	if (old_links == new_links && dormant_links == sdata->vif.dormant_links)
310 		return 0;
311 
312 	if (!old_links || !new_links)
313 		WARN_ON(sta_info_flush(sdata, -1) > 0);
314 
315 	/* if there were no old links, need to clear the pointers to deflink */
316 	if (!old_links)
317 		rem |= BIT(0);
318 
319 	/* allocate new link structures first */
320 	for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
321 		link = kzalloc_obj(*link);
322 		if (!link) {
323 			ret = -ENOMEM;
324 			goto free;
325 		}
326 		links[link_id] = link;
327 	}
328 
329 	/* keep track of the old pointers for the driver */
330 	BUILD_BUG_ON(sizeof(old) != sizeof(sdata->vif.link_conf));
331 	memcpy(old, sdata->vif.link_conf, sizeof(old));
332 	/* and for us in error cases */
333 	BUILD_BUG_ON(sizeof(old_data) != sizeof(sdata->link));
334 	memcpy(old_data, sdata->link, sizeof(old_data));
335 
336 	/* grab old links to free later */
337 	for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
338 		if (rcu_access_pointer(sdata->link[link_id]) != &sdata->deflink) {
339 			/*
340 			 * we must have allocated the data through this path so
341 			 * we know we can free both at the same time
342 			 */
343 			to_free[link_id] = container_of(rcu_access_pointer(sdata->link[link_id]),
344 							typeof(*links[link_id]),
345 							data);
346 		}
347 
348 		RCU_INIT_POINTER(sdata->link[link_id], NULL);
349 		RCU_INIT_POINTER(sdata->vif.link_conf[link_id], NULL);
350 	}
351 
352 	if (!old_links)
353 		ieee80211_debugfs_recreate_netdev(sdata, true);
354 
355 	/* link them into data structures */
356 	for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
357 		WARN_ON(!use_deflink &&
358 			rcu_access_pointer(sdata->link[link_id]) == &sdata->deflink);
359 
360 		link = links[link_id];
361 		ieee80211_link_init(sdata, link_id, &link->data, &link->conf);
362 		ieee80211_link_setup(&link->data);
363 		if (sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
364 			ieee80211_set_wmm_default(&link->data, true, non_sta);
365 	}
366 
367 	if (new_links == 0)
368 		ieee80211_link_init(sdata, -1, &sdata->deflink,
369 				    &sdata->vif.bss_conf);
370 
371 	ret = ieee80211_check_dup_link_addrs(sdata);
372 	if (!ret) {
373 		/* for keys we will not be able to undo this */
374 		ieee80211_tear_down_links(sdata, to_free, rem);
375 
376 		ieee80211_set_vif_links_bitmaps(sdata, new_links, dormant_links);
377 
378 		/* tell the driver */
379 		if (sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
380 			ret = drv_change_vif_links(sdata->local, sdata,
381 						   old_links & old_active,
382 						   new_links & sdata->vif.active_links,
383 						   old);
384 		if (!new_links)
385 			ieee80211_debugfs_recreate_netdev(sdata, false);
386 
387 		if (sdata->vif.type == NL80211_IFTYPE_AP)
388 			ieee80211_update_apvlan_links(sdata);
389 	}
390 
391 	/*
392 	 * Ignore errors if we are only removing links as removal should
393 	 * always succeed
394 	 */
395 	if (!new_links)
396 		ret = 0;
397 
398 	if (ret) {
399 		/* restore config */
400 		memcpy(sdata->link, old_data, sizeof(old_data));
401 		memcpy(sdata->vif.link_conf, old, sizeof(old));
402 		ieee80211_set_vif_links_bitmaps(sdata, old_links, dormant_links);
403 		for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
404 			ieee80211_link_debugfs_remove(&links[link_id]->data);
405 			ieee80211_link_stop(&links[link_id]->data);
406 		}
407 		/* and free (only) the newly allocated links */
408 		memset(to_free, 0, sizeof(links));
409 		goto free;
410 	}
411 
412 	/* try to remove links that are now invalid from (MLO) stations */
413 	list_for_each_entry(sta, &sdata->local->sta_list, list) {
414 		unsigned long rem_links = sta->sta.valid_links & sta_rem;
415 
416 		if (sta->sdata != sdata)
417 			continue;
418 
419 		/*
420 		 * skip stations that would have no links left,
421 		 * those will be removed completely later
422 		 */
423 		if (sta->sta.valid_links == rem_links)
424 			continue;
425 
426 		for_each_set_bit(link_id, &rem_links,
427 				 IEEE80211_MLD_MAX_NUM_LINKS)
428 			ieee80211_sta_remove_link(sta, link_id);
429 	}
430 
431 	/*
432 	 * Remove stations using any removed links. Note that due
433 	 * to the above station link removal, this only removes
434 	 * stations that were skipped above because they'd have no
435 	 * links left after link removal.
436 	 */
437 	for_each_set_bit(link_id, &sta_rem, IEEE80211_MLD_MAX_NUM_LINKS)
438 		sta_info_flush(sdata, link_id);
439 
440 	/* use deflink/bss_conf again if and only if there are no more links */
441 	use_deflink = new_links == 0;
442 
443 	goto deinit;
444 free:
445 	/* if we failed during allocation, only free all */
446 	for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++) {
447 		kfree(links[link_id]);
448 		links[link_id] = NULL;
449 	}
450 deinit:
451 	if (use_deflink)
452 		ieee80211_link_init(sdata, -1, &sdata->deflink,
453 				    &sdata->vif.bss_conf);
454 	return ret;
455 }
456 
457 int ieee80211_vif_set_links(struct ieee80211_sub_if_data *sdata,
458 			    u16 new_links, u16 dormant_links)
459 {
460 	struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS];
461 	int ret;
462 
463 	ret = ieee80211_vif_update_links(sdata, links, new_links,
464 					 dormant_links);
465 	ieee80211_free_links(sdata, links);
466 
467 	return ret;
468 }
469 
470 static int _ieee80211_set_active_links(struct ieee80211_sub_if_data *sdata,
471 				       u16 active_links)
472 {
473 	struct ieee80211_bss_conf *link_confs[IEEE80211_MLD_MAX_NUM_LINKS];
474 	struct ieee80211_local *local = sdata->local;
475 	u16 old_active = sdata->vif.active_links;
476 	unsigned long rem = old_active & ~active_links;
477 	unsigned long add = active_links & ~old_active;
478 	struct sta_info *sta;
479 	unsigned int link_id;
480 	int ret, i;
481 
482 	if (!ieee80211_sdata_running(sdata))
483 		return -ENETDOWN;
484 
485 	if (sdata->vif.type != NL80211_IFTYPE_STATION)
486 		return -EINVAL;
487 
488 	if (active_links & ~ieee80211_vif_usable_links(&sdata->vif))
489 		return -EINVAL;
490 
491 	/* nothing to do */
492 	if (old_active == active_links)
493 		return 0;
494 
495 	for (i = 0; i < IEEE80211_MLD_MAX_NUM_LINKS; i++)
496 		link_confs[i] = sdata_dereference(sdata->vif.link_conf[i],
497 						  sdata);
498 
499 	if (add) {
500 		sdata->vif.active_links |= active_links;
501 		ret = drv_change_vif_links(local, sdata,
502 					   old_active,
503 					   sdata->vif.active_links,
504 					   link_confs);
505 		if (ret) {
506 			sdata->vif.active_links = old_active;
507 			return ret;
508 		}
509 	}
510 
511 	for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
512 		struct ieee80211_link_data *link;
513 
514 		link = sdata_dereference(sdata->link[link_id], sdata);
515 
516 		ieee80211_teardown_tdls_peers(link);
517 
518 		__ieee80211_link_release_channel(link, true);
519 
520 		/*
521 		 * If CSA is (still) active while the link is deactivated,
522 		 * just schedule the channel switch work for the time we
523 		 * had previously calculated, and we'll take the process
524 		 * from there.
525 		 */
526 		if (link->conf->csa_active)
527 			wiphy_hrtimer_work_queue(local->hw.wiphy,
528 						 &link->u.mgd.csa.switch_work,
529 						 link->u.mgd.csa.time -
530 						 ktime_get_boottime());
531 	}
532 
533 	for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
534 		struct ieee80211_link_data *link;
535 
536 		link = sdata_dereference(sdata->link[link_id], sdata);
537 
538 		/*
539 		 * This call really should not fail. Unfortunately, it appears
540 		 * that this may happen occasionally with some drivers. Should
541 		 * it happen, we are stuck in a bad place as going backwards is
542 		 * not really feasible.
543 		 *
544 		 * So lets just tell link_use_channel that it must not fail to
545 		 * assign the channel context (from mac80211's perspective) and
546 		 * assume the driver is going to trigger a recovery flow if it
547 		 * had a failure.
548 		 * That really is not great nor guaranteed to work. But at least
549 		 * the internal mac80211 state remains consistent and there is
550 		 * a chance that we can recover.
551 		 */
552 		ret = _ieee80211_link_use_channel(link,
553 						  &link->conf->chanreq,
554 						  IEEE80211_CHANCTX_SHARED,
555 						  true);
556 		WARN_ON_ONCE(ret);
557 
558 		/*
559 		 * inform about the link info changed parameters after all
560 		 * stations are also added
561 		 */
562 	}
563 
564 	list_for_each_entry(sta, &local->sta_list, list) {
565 		if (sdata != sta->sdata)
566 			continue;
567 
568 		/* this is very temporary, but do it anyway */
569 		__ieee80211_sta_recalc_aggregates(sta,
570 						  old_active | active_links);
571 
572 		ret = drv_change_sta_links(local, sdata, &sta->sta,
573 					   old_active,
574 					   old_active | active_links);
575 		WARN_ON_ONCE(ret);
576 	}
577 
578 	ret = ieee80211_key_switch_links(sdata, rem, add);
579 	WARN_ON_ONCE(ret);
580 
581 	list_for_each_entry(sta, &local->sta_list, list) {
582 		if (sdata != sta->sdata)
583 			continue;
584 
585 		__ieee80211_sta_recalc_aggregates(sta, active_links);
586 
587 		ret = drv_change_sta_links(local, sdata, &sta->sta,
588 					   old_active | active_links,
589 					   active_links);
590 		WARN_ON_ONCE(ret);
591 
592 		/*
593 		 * Do it again, just in case - the driver might very
594 		 * well have called ieee80211_sta_recalc_aggregates()
595 		 * from there when filling in the new links, which
596 		 * would set it wrong since the vif's active links are
597 		 * not switched yet...
598 		 */
599 		__ieee80211_sta_recalc_aggregates(sta, active_links);
600 	}
601 
602 	for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
603 		struct ieee80211_link_data *link;
604 
605 		link = sdata_dereference(sdata->link[link_id], sdata);
606 
607 		ieee80211_mgd_set_link_qos_params(link);
608 		ieee80211_link_info_change_notify(sdata, link,
609 						  BSS_CHANGED_ERP_CTS_PROT |
610 						  BSS_CHANGED_ERP_PREAMBLE |
611 						  BSS_CHANGED_ERP_SLOT |
612 						  BSS_CHANGED_HT |
613 						  BSS_CHANGED_BASIC_RATES |
614 						  BSS_CHANGED_BSSID |
615 						  BSS_CHANGED_CQM |
616 						  BSS_CHANGED_QOS |
617 						  BSS_CHANGED_TXPOWER |
618 						  BSS_CHANGED_BANDWIDTH |
619 						  BSS_CHANGED_TWT |
620 						  BSS_CHANGED_HE_OBSS_PD |
621 						  BSS_CHANGED_HE_BSS_COLOR);
622 	}
623 
624 	old_active = sdata->vif.active_links;
625 	sdata->vif.active_links = active_links;
626 
627 	if (rem) {
628 		ret = drv_change_vif_links(local, sdata, old_active,
629 					   active_links, link_confs);
630 		WARN_ON_ONCE(ret);
631 	}
632 
633 	return 0;
634 }
635 
636 int ieee80211_set_active_links(struct ieee80211_vif *vif, u16 active_links)
637 {
638 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
639 	struct ieee80211_local *local = sdata->local;
640 	u16 old_active;
641 	int ret;
642 
643 	lockdep_assert_wiphy(local->hw.wiphy);
644 
645 	if (WARN_ON(!active_links))
646 		return -EINVAL;
647 
648 	old_active = sdata->vif.active_links;
649 	if (old_active == active_links)
650 		return 0;
651 
652 	if (!drv_can_activate_links(local, sdata, active_links))
653 		return -EINVAL;
654 
655 	if (old_active & active_links) {
656 		/*
657 		 * if there's at least one link that stays active across
658 		 * the change then switch to it (to those) first, and
659 		 * then enable the additional links
660 		 */
661 		ret = _ieee80211_set_active_links(sdata,
662 						  old_active & active_links);
663 		if (!ret)
664 			ret = _ieee80211_set_active_links(sdata, active_links);
665 	} else {
666 		/* otherwise switch directly */
667 		ret = _ieee80211_set_active_links(sdata, active_links);
668 	}
669 
670 	return ret;
671 }
672 EXPORT_SYMBOL_GPL(ieee80211_set_active_links);
673 
674 void ieee80211_set_active_links_async(struct ieee80211_vif *vif,
675 				      u16 active_links)
676 {
677 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
678 
679 	if (WARN_ON(!active_links))
680 		return;
681 
682 	if (!ieee80211_sdata_running(sdata))
683 		return;
684 
685 	if (sdata->vif.type != NL80211_IFTYPE_STATION)
686 		return;
687 
688 	if (active_links & ~ieee80211_vif_usable_links(&sdata->vif))
689 		return;
690 
691 	/* nothing to do */
692 	if (sdata->vif.active_links == active_links)
693 		return;
694 
695 	sdata->desired_active_links = active_links;
696 	wiphy_work_queue(sdata->local->hw.wiphy, &sdata->activate_links_work);
697 }
698 EXPORT_SYMBOL_GPL(ieee80211_set_active_links_async);
699