link.c

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