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(sdata: vlan, new_links: add, dormant_links: 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(dst: sdata->wdev.links[link_id].addr,
62 src: ap_bss->wdev.links[link_id].addr);
63 }
64
65 ieee80211_vif_set_links(sdata, new_links, dormant_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(work: &link->csa.finalize_work,
114 func: ieee80211_csa_finalize_work);
115 wiphy_work_init(work: &link->color_change_finalize_work,
116 func: ieee80211_color_change_finalize_work);
117 wiphy_delayed_work_init(dwork: &link->color_collision_detect_work,
118 func: ieee80211_color_collision_detection_work);
119 wiphy_delayed_work_init(dwork: &link->dfs_cac_timer_work,
120 func: 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(dst: link_conf->addr,
127 src: 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(wiphy: link->sdata->local->hw.wiphy,
151 dwork: &link->color_collision_detect_work);
152 wiphy_work_cancel(wiphy: link->sdata->local->hw.wiphy,
153 work: &link->color_change_finalize_work);
154 wiphy_work_cancel(wiphy: link->sdata->local->hw.wiphy,
155 work: &link->csa.finalize_work);
156
157 if (link->sdata->wdev.links[link->link_id].cac_started) {
158 wiphy_delayed_work_cancel(wiphy: link->sdata->local->hw.wiphy,
159 dwork: &link->dfs_cac_timer_work);
160 cfg80211_cac_event(netdev: link->sdata->dev,
161 chandef: &link->conf->chanreq.oper,
162 event: NL80211_RADAR_CAC_ABORTED,
163 GFP_KERNEL, link_id: 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: &keys);
190 ieee80211_link_debugfs_remove(link);
191 ieee80211_link_stop(link);
192 }
193
194 synchronize_rcu();
195
196 ieee80211_free_key_list(local: sdata->local, keys: &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(objp: 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(addr1: link1->conf->addr,
226 addr2: 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
285 lockdep_assert_wiphy(sdata->local->hw.wiphy);
286
287 memset(to_free, 0, sizeof(links));
288
289 if (old_links == new_links && dormant_links == sdata->vif.dormant_links)
290 return 0;
291
292 /* if there were no old links, need to clear the pointers to deflink */
293 if (!old_links)
294 rem |= BIT(0);
295
296 /* allocate new link structures first */
297 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
298 link = kzalloc(sizeof(*link), GFP_KERNEL);
299 if (!link) {
300 ret = -ENOMEM;
301 goto free;
302 }
303 links[link_id] = link;
304 }
305
306 /* keep track of the old pointers for the driver */
307 BUILD_BUG_ON(sizeof(old) != sizeof(sdata->vif.link_conf));
308 memcpy(old, sdata->vif.link_conf, sizeof(old));
309 /* and for us in error cases */
310 BUILD_BUG_ON(sizeof(old_data) != sizeof(sdata->link));
311 memcpy(old_data, sdata->link, sizeof(old_data));
312
313 /* grab old links to free later */
314 for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
315 if (rcu_access_pointer(sdata->link[link_id]) != &sdata->deflink) {
316 /*
317 * we must have allocated the data through this path so
318 * we know we can free both at the same time
319 */
320 to_free[link_id] = container_of(rcu_access_pointer(sdata->link[link_id]),
321 typeof(*links[link_id]),
322 data);
323 }
324
325 RCU_INIT_POINTER(sdata->link[link_id], NULL);
326 RCU_INIT_POINTER(sdata->vif.link_conf[link_id], NULL);
327 }
328
329 if (!old_links)
330 ieee80211_debugfs_recreate_netdev(sdata, mld_vif: true);
331
332 /* link them into data structures */
333 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
334 WARN_ON(!use_deflink &&
335 rcu_access_pointer(sdata->link[link_id]) == &sdata->deflink);
336
337 link = links[link_id];
338 ieee80211_link_init(sdata, link_id, link: &link->data, link_conf: &link->conf);
339 ieee80211_link_setup(link: &link->data);
340 }
341
342 if (new_links == 0)
343 ieee80211_link_init(sdata, link_id: -1, link: &sdata->deflink,
344 link_conf: &sdata->vif.bss_conf);
345
346 ret = ieee80211_check_dup_link_addrs(sdata);
347 if (!ret) {
348 /* for keys we will not be able to undo this */
349 ieee80211_tear_down_links(sdata, links: to_free, mask: rem);
350
351 ieee80211_set_vif_links_bitmaps(sdata, valid_links: new_links, dormant_links);
352
353 /* tell the driver */
354 if (sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
355 ret = drv_change_vif_links(local: sdata->local, sdata,
356 old_links: old_links & old_active,
357 new_links: new_links & sdata->vif.active_links,
358 old);
359 if (!new_links)
360 ieee80211_debugfs_recreate_netdev(sdata, mld_vif: false);
361
362 if (sdata->vif.type == NL80211_IFTYPE_AP)
363 ieee80211_update_apvlan_links(sdata);
364 }
365
366 /*
367 * Ignore errors if we are only removing links as removal should
368 * always succeed
369 */
370 if (!new_links)
371 ret = 0;
372
373 if (ret) {
374 /* restore config */
375 memcpy(sdata->link, old_data, sizeof(old_data));
376 memcpy(sdata->vif.link_conf, old, sizeof(old));
377 ieee80211_set_vif_links_bitmaps(sdata, valid_links: old_links, dormant_links);
378 /* and free (only) the newly allocated links */
379 memset(to_free, 0, sizeof(links));
380 goto free;
381 }
382
383 /* use deflink/bss_conf again if and only if there are no more links */
384 use_deflink = new_links == 0;
385
386 goto deinit;
387free:
388 /* if we failed during allocation, only free all */
389 for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++) {
390 kfree(objp: links[link_id]);
391 links[link_id] = NULL;
392 }
393deinit:
394 if (use_deflink)
395 ieee80211_link_init(sdata, link_id: -1, link: &sdata->deflink,
396 link_conf: &sdata->vif.bss_conf);
397 return ret;
398}
399
400int ieee80211_vif_set_links(struct ieee80211_sub_if_data *sdata,
401 u16 new_links, u16 dormant_links)
402{
403 struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS];
404 int ret;
405
406 ret = ieee80211_vif_update_links(sdata, to_free: links, new_links,
407 dormant_links);
408 ieee80211_free_links(sdata, links);
409
410 return ret;
411}
412
413static int _ieee80211_set_active_links(struct ieee80211_sub_if_data *sdata,
414 u16 active_links)
415{
416 struct ieee80211_bss_conf *link_confs[IEEE80211_MLD_MAX_NUM_LINKS];
417 struct ieee80211_local *local = sdata->local;
418 u16 old_active = sdata->vif.active_links;
419 unsigned long rem = old_active & ~active_links;
420 unsigned long add = active_links & ~old_active;
421 struct sta_info *sta;
422 unsigned int link_id;
423 int ret, i;
424
425 if (!ieee80211_sdata_running(sdata))
426 return -ENETDOWN;
427
428 if (sdata->vif.type != NL80211_IFTYPE_STATION)
429 return -EINVAL;
430
431 if (active_links & ~ieee80211_vif_usable_links(vif: &sdata->vif))
432 return -EINVAL;
433
434 /* nothing to do */
435 if (old_active == active_links)
436 return 0;
437
438 for (i = 0; i < IEEE80211_MLD_MAX_NUM_LINKS; i++)
439 link_confs[i] = sdata_dereference(sdata->vif.link_conf[i],
440 sdata);
441
442 if (add) {
443 sdata->vif.active_links |= active_links;
444 ret = drv_change_vif_links(local, sdata,
445 old_links: old_active,
446 new_links: sdata->vif.active_links,
447 old: link_confs);
448 if (ret) {
449 sdata->vif.active_links = old_active;
450 return ret;
451 }
452 }
453
454 for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
455 struct ieee80211_link_data *link;
456
457 link = sdata_dereference(sdata->link[link_id], sdata);
458
459 ieee80211_teardown_tdls_peers(link);
460
461 __ieee80211_link_release_channel(link, skip_idle_recalc: true);
462
463 /*
464 * If CSA is (still) active while the link is deactivated,
465 * just schedule the channel switch work for the time we
466 * had previously calculated, and we'll take the process
467 * from there.
468 */
469 if (link->conf->csa_active)
470 wiphy_hrtimer_work_queue(wiphy: local->hw.wiphy,
471 hrwork: &link->u.mgd.csa.switch_work,
472 delay: link->u.mgd.csa.time -
473 ktime_get_boottime());
474 }
475
476 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
477 struct ieee80211_link_data *link;
478
479 link = sdata_dereference(sdata->link[link_id], sdata);
480
481 /*
482 * This call really should not fail. Unfortunately, it appears
483 * that this may happen occasionally with some drivers. Should
484 * it happen, we are stuck in a bad place as going backwards is
485 * not really feasible.
486 *
487 * So lets just tell link_use_channel that it must not fail to
488 * assign the channel context (from mac80211's perspective) and
489 * assume the driver is going to trigger a recovery flow if it
490 * had a failure.
491 * That really is not great nor guaranteed to work. But at least
492 * the internal mac80211 state remains consistent and there is
493 * a chance that we can recover.
494 */
495 ret = _ieee80211_link_use_channel(link,
496 req: &link->conf->chanreq,
497 mode: IEEE80211_CHANCTX_SHARED,
498 assign_on_failure: true);
499 WARN_ON_ONCE(ret);
500
501 /*
502 * inform about the link info changed parameters after all
503 * stations are also added
504 */
505 }
506
507 list_for_each_entry(sta, &local->sta_list, list) {
508 if (sdata != sta->sdata)
509 continue;
510
511 /* this is very temporary, but do it anyway */
512 __ieee80211_sta_recalc_aggregates(sta,
513 active_links: old_active | active_links);
514
515 ret = drv_change_sta_links(local, sdata, sta: &sta->sta,
516 old_links: old_active,
517 new_links: old_active | active_links);
518 WARN_ON_ONCE(ret);
519 }
520
521 ret = ieee80211_key_switch_links(sdata, del_links_mask: rem, add_links_mask: add);
522 WARN_ON_ONCE(ret);
523
524 list_for_each_entry(sta, &local->sta_list, list) {
525 if (sdata != sta->sdata)
526 continue;
527
528 __ieee80211_sta_recalc_aggregates(sta, active_links);
529
530 ret = drv_change_sta_links(local, sdata, sta: &sta->sta,
531 old_links: old_active | active_links,
532 new_links: active_links);
533 WARN_ON_ONCE(ret);
534
535 /*
536 * Do it again, just in case - the driver might very
537 * well have called ieee80211_sta_recalc_aggregates()
538 * from there when filling in the new links, which
539 * would set it wrong since the vif's active links are
540 * not switched yet...
541 */
542 __ieee80211_sta_recalc_aggregates(sta, active_links);
543 }
544
545 for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
546 struct ieee80211_link_data *link;
547
548 link = sdata_dereference(sdata->link[link_id], sdata);
549
550 ieee80211_mgd_set_link_qos_params(link);
551 ieee80211_link_info_change_notify(sdata, link,
552 changed: BSS_CHANGED_ERP_CTS_PROT |
553 BSS_CHANGED_ERP_PREAMBLE |
554 BSS_CHANGED_ERP_SLOT |
555 BSS_CHANGED_HT |
556 BSS_CHANGED_BASIC_RATES |
557 BSS_CHANGED_BSSID |
558 BSS_CHANGED_CQM |
559 BSS_CHANGED_QOS |
560 BSS_CHANGED_TXPOWER |
561 BSS_CHANGED_BANDWIDTH |
562 BSS_CHANGED_TWT |
563 BSS_CHANGED_HE_OBSS_PD |
564 BSS_CHANGED_HE_BSS_COLOR);
565 }
566
567 old_active = sdata->vif.active_links;
568 sdata->vif.active_links = active_links;
569
570 if (rem) {
571 ret = drv_change_vif_links(local, sdata, old_links: old_active,
572 new_links: active_links, old: link_confs);
573 WARN_ON_ONCE(ret);
574 }
575
576 return 0;
577}
578
579int ieee80211_set_active_links(struct ieee80211_vif *vif, u16 active_links)
580{
581 struct ieee80211_sub_if_data *sdata = vif_to_sdata(p: vif);
582 struct ieee80211_local *local = sdata->local;
583 u16 old_active;
584 int ret;
585
586 lockdep_assert_wiphy(local->hw.wiphy);
587
588 if (WARN_ON(!active_links))
589 return -EINVAL;
590
591 old_active = sdata->vif.active_links;
592 if (old_active == active_links)
593 return 0;
594
595 if (!drv_can_activate_links(local, sdata, active_links))
596 return -EINVAL;
597
598 if (old_active & active_links) {
599 /*
600 * if there's at least one link that stays active across
601 * the change then switch to it (to those) first, and
602 * then enable the additional links
603 */
604 ret = _ieee80211_set_active_links(sdata,
605 active_links: old_active & active_links);
606 if (!ret)
607 ret = _ieee80211_set_active_links(sdata, active_links);
608 } else {
609 /* otherwise switch directly */
610 ret = _ieee80211_set_active_links(sdata, active_links);
611 }
612
613 return ret;
614}
615EXPORT_SYMBOL_GPL(ieee80211_set_active_links);
616
617void ieee80211_set_active_links_async(struct ieee80211_vif *vif,
618 u16 active_links)
619{
620 struct ieee80211_sub_if_data *sdata = vif_to_sdata(p: vif);
621
622 if (WARN_ON(!active_links))
623 return;
624
625 if (!ieee80211_sdata_running(sdata))
626 return;
627
628 if (sdata->vif.type != NL80211_IFTYPE_STATION)
629 return;
630
631 if (active_links & ~ieee80211_vif_usable_links(vif: &sdata->vif))
632 return;
633
634 /* nothing to do */
635 if (sdata->vif.active_links == active_links)
636 return;
637
638 sdata->desired_active_links = active_links;
639 wiphy_work_queue(wiphy: sdata->local->hw.wiphy, work: &sdata->activate_links_work);
640}
641EXPORT_SYMBOL_GPL(ieee80211_set_active_links_async);
642

source code of linux/net/mac80211/link.c