xref: /linux/net/mac80211/link.c (revision a10ea943356b9d70c5616a0a06f6fa97cfdaccb1)
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 		ieee80211_set_wmm_default(&link->data, true, non_sta);
364 	}
365 
366 	if (new_links == 0)
367 		ieee80211_link_init(sdata, -1, &sdata->deflink,
368 				    &sdata->vif.bss_conf);
369 
370 	ret = ieee80211_check_dup_link_addrs(sdata);
371 	if (!ret) {
372 		/* for keys we will not be able to undo this */
373 		ieee80211_tear_down_links(sdata, to_free, rem);
374 
375 		ieee80211_set_vif_links_bitmaps(sdata, new_links, dormant_links);
376 
377 		/* tell the driver */
378 		if (sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
379 			ret = drv_change_vif_links(sdata->local, sdata,
380 						   old_links & old_active,
381 						   new_links & sdata->vif.active_links,
382 						   old);
383 		if (!new_links)
384 			ieee80211_debugfs_recreate_netdev(sdata, false);
385 
386 		if (sdata->vif.type == NL80211_IFTYPE_AP)
387 			ieee80211_update_apvlan_links(sdata);
388 	}
389 
390 	/*
391 	 * Ignore errors if we are only removing links as removal should
392 	 * always succeed
393 	 */
394 	if (!new_links)
395 		ret = 0;
396 
397 	if (ret) {
398 		/* restore config */
399 		memcpy(sdata->link, old_data, sizeof(old_data));
400 		memcpy(sdata->vif.link_conf, old, sizeof(old));
401 		ieee80211_set_vif_links_bitmaps(sdata, old_links, dormant_links);
402 		for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
403 			ieee80211_link_debugfs_remove(&links[link_id]->data);
404 			ieee80211_link_stop(&links[link_id]->data);
405 		}
406 		/* and free (only) the newly allocated links */
407 		memset(to_free, 0, sizeof(links));
408 		goto free;
409 	}
410 
411 	/* try to remove links that are now invalid from (MLO) stations */
412 	list_for_each_entry(sta, &sdata->local->sta_list, list) {
413 		unsigned long rem_links = sta->sta.valid_links & sta_rem;
414 
415 		if (sta->sdata != sdata)
416 			continue;
417 
418 		/*
419 		 * skip stations that would have no links left,
420 		 * those will be removed completely later
421 		 */
422 		if (sta->sta.valid_links == rem_links)
423 			continue;
424 
425 		for_each_set_bit(link_id, &rem_links,
426 				 IEEE80211_MLD_MAX_NUM_LINKS)
427 			ieee80211_sta_remove_link(sta, link_id);
428 	}
429 
430 	/*
431 	 * Remove stations using any removed links. Note that due
432 	 * to the above station link removal, this only removes
433 	 * stations that were skipped above because they'd have no
434 	 * links left after link removal.
435 	 */
436 	for_each_set_bit(link_id, &sta_rem, IEEE80211_MLD_MAX_NUM_LINKS)
437 		sta_info_flush(sdata, link_id);
438 
439 	/* use deflink/bss_conf again if and only if there are no more links */
440 	use_deflink = new_links == 0;
441 
442 	goto deinit;
443 free:
444 	/* if we failed during allocation, only free all */
445 	for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++) {
446 		kfree(links[link_id]);
447 		links[link_id] = NULL;
448 	}
449 deinit:
450 	if (use_deflink)
451 		ieee80211_link_init(sdata, -1, &sdata->deflink,
452 				    &sdata->vif.bss_conf);
453 	return ret;
454 }
455 
456 int ieee80211_vif_set_links(struct ieee80211_sub_if_data *sdata,
457 			    u16 new_links, u16 dormant_links)
458 {
459 	struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS];
460 	int ret;
461 
462 	ret = ieee80211_vif_update_links(sdata, links, new_links,
463 					 dormant_links);
464 	ieee80211_free_links(sdata, links);
465 
466 	return ret;
467 }
468 
469 static int _ieee80211_set_active_links(struct ieee80211_sub_if_data *sdata,
470 				       u16 active_links)
471 {
472 	struct ieee80211_bss_conf *link_confs[IEEE80211_MLD_MAX_NUM_LINKS];
473 	struct ieee80211_local *local = sdata->local;
474 	u16 old_active = sdata->vif.active_links;
475 	unsigned long rem = old_active & ~active_links;
476 	unsigned long add = active_links & ~old_active;
477 	struct sta_info *sta;
478 	unsigned int link_id;
479 	int ret, i;
480 
481 	if (!ieee80211_sdata_running(sdata))
482 		return -ENETDOWN;
483 
484 	if (sdata->vif.type != NL80211_IFTYPE_STATION)
485 		return -EINVAL;
486 
487 	if (active_links & ~ieee80211_vif_usable_links(&sdata->vif))
488 		return -EINVAL;
489 
490 	/* nothing to do */
491 	if (old_active == active_links)
492 		return 0;
493 
494 	for (i = 0; i < IEEE80211_MLD_MAX_NUM_LINKS; i++)
495 		link_confs[i] = sdata_dereference(sdata->vif.link_conf[i],
496 						  sdata);
497 
498 	if (add) {
499 		sdata->vif.active_links |= active_links;
500 		ret = drv_change_vif_links(local, sdata,
501 					   old_active,
502 					   sdata->vif.active_links,
503 					   link_confs);
504 		if (ret) {
505 			sdata->vif.active_links = old_active;
506 			return ret;
507 		}
508 	}
509 
510 	for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
511 		struct ieee80211_link_data *link;
512 
513 		link = sdata_dereference(sdata->link[link_id], sdata);
514 
515 		ieee80211_teardown_tdls_peers(link);
516 
517 		__ieee80211_link_release_channel(link, true);
518 
519 		/*
520 		 * If CSA is (still) active while the link is deactivated,
521 		 * just schedule the channel switch work for the time we
522 		 * had previously calculated, and we'll take the process
523 		 * from there.
524 		 */
525 		if (link->conf->csa_active)
526 			wiphy_hrtimer_work_queue(local->hw.wiphy,
527 						 &link->u.mgd.csa.switch_work,
528 						 link->u.mgd.csa.time -
529 						 ktime_get_boottime());
530 	}
531 
532 	for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
533 		struct ieee80211_link_data *link;
534 
535 		link = sdata_dereference(sdata->link[link_id], sdata);
536 
537 		/*
538 		 * This call really should not fail. Unfortunately, it appears
539 		 * that this may happen occasionally with some drivers. Should
540 		 * it happen, we are stuck in a bad place as going backwards is
541 		 * not really feasible.
542 		 *
543 		 * So lets just tell link_use_channel that it must not fail to
544 		 * assign the channel context (from mac80211's perspective) and
545 		 * assume the driver is going to trigger a recovery flow if it
546 		 * had a failure.
547 		 * That really is not great nor guaranteed to work. But at least
548 		 * the internal mac80211 state remains consistent and there is
549 		 * a chance that we can recover.
550 		 */
551 		ret = _ieee80211_link_use_channel(link,
552 						  &link->conf->chanreq,
553 						  IEEE80211_CHANCTX_SHARED,
554 						  true);
555 		WARN_ON_ONCE(ret);
556 
557 		/*
558 		 * inform about the link info changed parameters after all
559 		 * stations are also added
560 		 */
561 	}
562 
563 	list_for_each_entry(sta, &local->sta_list, list) {
564 		if (sdata != sta->sdata)
565 			continue;
566 
567 		/* this is very temporary, but do it anyway */
568 		__ieee80211_sta_recalc_aggregates(sta,
569 						  old_active | active_links);
570 
571 		ret = drv_change_sta_links(local, sdata, &sta->sta,
572 					   old_active,
573 					   old_active | active_links);
574 		WARN_ON_ONCE(ret);
575 	}
576 
577 	ret = ieee80211_key_switch_links(sdata, rem, add);
578 	WARN_ON_ONCE(ret);
579 
580 	list_for_each_entry(sta, &local->sta_list, list) {
581 		if (sdata != sta->sdata)
582 			continue;
583 
584 		__ieee80211_sta_recalc_aggregates(sta, active_links);
585 
586 		ret = drv_change_sta_links(local, sdata, &sta->sta,
587 					   old_active | active_links,
588 					   active_links);
589 		WARN_ON_ONCE(ret);
590 
591 		/*
592 		 * Do it again, just in case - the driver might very
593 		 * well have called ieee80211_sta_recalc_aggregates()
594 		 * from there when filling in the new links, which
595 		 * would set it wrong since the vif's active links are
596 		 * not switched yet...
597 		 */
598 		__ieee80211_sta_recalc_aggregates(sta, active_links);
599 	}
600 
601 	for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
602 		struct ieee80211_link_data *link;
603 
604 		link = sdata_dereference(sdata->link[link_id], sdata);
605 
606 		ieee80211_mgd_set_link_qos_params(link);
607 		ieee80211_link_info_change_notify(sdata, link,
608 						  BSS_CHANGED_ERP_CTS_PROT |
609 						  BSS_CHANGED_ERP_PREAMBLE |
610 						  BSS_CHANGED_ERP_SLOT |
611 						  BSS_CHANGED_HT |
612 						  BSS_CHANGED_BASIC_RATES |
613 						  BSS_CHANGED_BSSID |
614 						  BSS_CHANGED_CQM |
615 						  BSS_CHANGED_QOS |
616 						  BSS_CHANGED_TXPOWER |
617 						  BSS_CHANGED_BANDWIDTH |
618 						  BSS_CHANGED_TWT |
619 						  BSS_CHANGED_HE_OBSS_PD |
620 						  BSS_CHANGED_HE_BSS_COLOR);
621 	}
622 
623 	old_active = sdata->vif.active_links;
624 	sdata->vif.active_links = active_links;
625 
626 	if (rem) {
627 		ret = drv_change_vif_links(local, sdata, old_active,
628 					   active_links, link_confs);
629 		WARN_ON_ONCE(ret);
630 	}
631 
632 	return 0;
633 }
634 
635 int ieee80211_set_active_links(struct ieee80211_vif *vif, u16 active_links)
636 {
637 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
638 	struct ieee80211_local *local = sdata->local;
639 	u16 old_active;
640 	int ret;
641 
642 	lockdep_assert_wiphy(local->hw.wiphy);
643 
644 	if (WARN_ON(!active_links))
645 		return -EINVAL;
646 
647 	old_active = sdata->vif.active_links;
648 	if (old_active == active_links)
649 		return 0;
650 
651 	if (!drv_can_activate_links(local, sdata, active_links))
652 		return -EINVAL;
653 
654 	if (old_active & active_links) {
655 		/*
656 		 * if there's at least one link that stays active across
657 		 * the change then switch to it (to those) first, and
658 		 * then enable the additional links
659 		 */
660 		ret = _ieee80211_set_active_links(sdata,
661 						  old_active & active_links);
662 		if (!ret)
663 			ret = _ieee80211_set_active_links(sdata, active_links);
664 	} else {
665 		/* otherwise switch directly */
666 		ret = _ieee80211_set_active_links(sdata, active_links);
667 	}
668 
669 	return ret;
670 }
671 EXPORT_SYMBOL_GPL(ieee80211_set_active_links);
672 
673 void ieee80211_set_active_links_async(struct ieee80211_vif *vif,
674 				      u16 active_links)
675 {
676 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
677 
678 	if (WARN_ON(!active_links))
679 		return;
680 
681 	if (!ieee80211_sdata_running(sdata))
682 		return;
683 
684 	if (sdata->vif.type != NL80211_IFTYPE_STATION)
685 		return;
686 
687 	if (active_links & ~ieee80211_vif_usable_links(&sdata->vif))
688 		return;
689 
690 	/* nothing to do */
691 	if (sdata->vif.active_links == active_links)
692 		return;
693 
694 	sdata->desired_active_links = active_links;
695 	wiphy_work_queue(sdata->local->hw.wiphy, &sdata->activate_links_work);
696 }
697 EXPORT_SYMBOL_GPL(ieee80211_set_active_links_async);
698