summaryrefslogtreecommitdiff
path: root/net/mac80211/offchannel.c
blob: 8b2f4eaac2ba65f8e25ae47dc316bf288ef8e0e9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
/*
 * Off-channel operation helpers
 *
 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 * Copyright 2009	Johannes Berg <johannes@sipsolutions.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/export.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"

/*
 * Tell our hardware to disable PS.
 * Optionally inform AP that we will go to sleep so that it will buffer
 * the frames while we are doing off-channel work.  This is optional
 * because we *may* be doing work on-operating channel, and want our
 * hardware unconditionally awake, but still let the AP send us normal frames.
 */
static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;

	local->offchannel_ps_enabled = false;

	/* FIXME: what to do when local->pspolling is true? */

	del_timer_sync(&local->dynamic_ps_timer);
	del_timer_sync(&ifmgd->bcn_mon_timer);
	del_timer_sync(&ifmgd->conn_mon_timer);

	cancel_work_sync(&local->dynamic_ps_enable_work);

	if (local->hw.conf.flags & IEEE80211_CONF_PS) {
		local->offchannel_ps_enabled = true;
		local->hw.conf.flags &= ~IEEE80211_CONF_PS;
		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
	}

	if (!local->offchannel_ps_enabled ||
	    !ieee80211_hw_check(&local->hw, PS_NULLFUNC_STACK))
		/*
		 * If power save was enabled, no need to send a nullfunc
		 * frame because AP knows that we are sleeping. But if the
		 * hardware is creating the nullfunc frame for power save
		 * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
		 * enabled) and power save was enabled, the firmware just
		 * sent a null frame with power save disabled. So we need
		 * to send a new nullfunc frame to inform the AP that we
		 * are again sleeping.
		 */
		ieee80211_send_nullfunc(local, sdata, true);
}

/* inform AP that we are awake again, unless power save is enabled */
static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_local *local = sdata->local;

	if (!local->ps_sdata)
		ieee80211_send_nullfunc(local, sdata, false);
	else if (local->offchannel_ps_enabled) {
		/*
		 * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
		 * will send a nullfunc frame with the powersave bit set
		 * even though the AP already knows that we are sleeping.
		 * This could be avoided by sending a null frame with power
		 * save bit disabled before enabling the power save, but
		 * this doesn't gain anything.
		 *
		 * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
		 * to send a nullfunc frame because AP already knows that
		 * we are sleeping, let's just enable power save mode in
		 * hardware.
		 */
		/* TODO:  Only set hardware if CONF_PS changed?
		 * TODO:  Should we set offchannel_ps_enabled to false?
		 */
		local->hw.conf.flags |= IEEE80211_CONF_PS;
		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
	} else if (local->hw.conf.dynamic_ps_timeout > 0) {
		/*
		 * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
		 * had been running before leaving the operating channel,
		 * restart the timer now and send a nullfunc frame to inform
		 * the AP that we are awake.
		 */
		ieee80211_send_nullfunc(local, sdata, false);
		mod_timer(&local->dynamic_ps_timer, jiffies +
			  msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
	}

	ieee80211_sta_reset_beacon_monitor(sdata);
	ieee80211_sta_reset_conn_monitor(sdata);
}

void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local)
{
	struct ieee80211_sub_if_data *sdata;

	if (WARN_ON(local->use_chanctx))
		return;

	/*
	 * notify the AP about us leaving the channel and stop all
	 * STA interfaces.
	 */

	/*
	 * Stop queues and transmit all frames queued by the driver
	 * before sending nullfunc to enable powersave at the AP.
	 */
	ieee80211_stop_queues_by_reason(&local->hw, IEEE80211_MAX_QUEUE_MAP,
					IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
					false);
	ieee80211_flush_queues(local, NULL, false);

	mutex_lock(&local->iflist_mtx);
	list_for_each_entry(sdata, &local->interfaces, list) {
		if (!ieee80211_sdata_running(sdata))
			continue;

		if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
			continue;

		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
			set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);

		/* Check to see if we should disable beaconing. */
		if (sdata->vif.bss_conf.enable_beacon) {
			set_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
				&sdata->state);
			sdata->vif.bss_conf.enable_beacon = false;
			ieee80211_bss_info_change_notify(
				sdata, BSS_CHANGED_BEACON_ENABLED);
		}

		if (sdata->vif.type == NL80211_IFTYPE_STATION &&
		    sdata->u.mgd.associated)
			ieee80211_offchannel_ps_enable(sdata);
	}
	mutex_unlock(&local->iflist_mtx);
}

void ieee80211_offchannel_return(struct ieee80211_local *local)
{
	struct ieee80211_sub_if_data *sdata;

	if (WARN_ON(local->use_chanctx))
		return;

	mutex_lock(&local->iflist_mtx);
	list_for_each_entry(sdata, &local->interfaces, list) {
		if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
			continue;

		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
			clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);

		if (!ieee80211_sdata_running(sdata))
			continue;

		/* Tell AP we're back */
		if (sdata->vif.type == NL80211_IFTYPE_STATION &&
		    sdata->u.mgd.associated)
			ieee80211_offchannel_ps_disable(sdata);

		if (test_and_clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
				       &sdata->state)) {
			sdata->vif.bss_conf.enable_beacon = true;
			ieee80211_bss_info_change_notify(
				sdata, BSS_CHANGED_BEACON_ENABLED);
		}
	}
	mutex_unlock(&local->iflist_mtx);

	ieee80211_wake_queues_by_reason(&local->hw, IEEE80211_MAX_QUEUE_MAP,
					IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
					false);
}

static void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc)
{
	/* was never transmitted */
	if (roc->frame) {
		cfg80211_mgmt_tx_status(&roc->sdata->wdev, roc->mgmt_tx_cookie,
					roc->frame->data, roc->frame->len,
					false, GFP_KERNEL);
		ieee80211_free_txskb(&roc->sdata->local->hw, roc->frame);
	}

	if (!roc->mgmt_tx_cookie)
		cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
						   roc->cookie, roc->chan,
						   GFP_KERNEL);

	list_del(&roc->list);
	kfree(roc);
}

static unsigned long ieee80211_end_finished_rocs(struct ieee80211_local *local,
						 unsigned long now)
{
	struct ieee80211_roc_work *roc, *tmp;
	long remaining_dur_min = LONG_MAX;

	lockdep_assert_held(&local->mtx);

	list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
		long remaining;

		if (!roc->started)
			break;

		remaining = roc->start_time +
			    msecs_to_jiffies(roc->duration) -
			    now;

		/* In case of HW ROC, it is possible that the HW finished the
		 * ROC session before the actual requested time. In such a case
		 * end the ROC session (disregarding the remaining time).
		 */
		if (roc->abort || roc->hw_begun || remaining <= 0)
			ieee80211_roc_notify_destroy(roc);
		else
			remaining_dur_min = min(remaining_dur_min, remaining);
	}

	return remaining_dur_min;
}

static bool ieee80211_recalc_sw_work(struct ieee80211_local *local,
				     unsigned long now)
{
	long dur = ieee80211_end_finished_rocs(local, now);

	if (dur == LONG_MAX)
		return false;

	mod_delayed_work(local->workqueue, &local->roc_work, dur);
	return true;
}

static void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc,
					 unsigned long start_time)
{
	struct ieee80211_local *local = roc->sdata->local;

	if (WARN_ON(roc->notified))
		return;

	roc->start_time = start_time;
	roc->started = true;
	roc->hw_begun = true;

	if (roc->mgmt_tx_cookie) {
		if (!WARN_ON(!roc->frame)) {
			ieee80211_tx_skb_tid_band(roc->sdata, roc->frame, 7,
						  roc->chan->band);
			roc->frame = NULL;
		}
	} else {
		cfg80211_ready_on_channel(&roc->sdata->wdev, roc->cookie,
					  roc->chan, roc->req_duration,
					  GFP_KERNEL);
	}

	roc->notified = true;

	if (!local->ops->remain_on_channel)
		ieee80211_recalc_sw_work(local, start_time);
}

static void ieee80211_hw_roc_start(struct work_struct *work)
{
	struct ieee80211_local *local =
		container_of(work, struct ieee80211_local, hw_roc_start);
	struct ieee80211_roc_work *roc;

	mutex_lock(&local->mtx);

	list_for_each_entry(roc, &local->roc_list, list) {
		if (!roc->started)
			break;

		ieee80211_handle_roc_started(roc, local->hw_roc_start_time);
	}

	mutex_unlock(&local->mtx);
}

void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
{
	struct ieee80211_local *local = hw_to_local(hw);

	local->hw_roc_start_time = jiffies;

	trace_api_ready_on_channel(local);

	ieee80211_queue_work(hw, &local->hw_roc_start);
}
EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);

static void _ieee80211_start_next_roc(struct ieee80211_local *local)
{
	struct ieee80211_roc_work *roc, *tmp;
	enum ieee80211_roc_type type;
	u32 min_dur, max_dur;

	lockdep_assert_held(&local->mtx);

	if (WARN_ON(list_empty(&local->roc_list)))
		return;

	roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
			       list);

	if (WARN_ON(roc->started))
		return;

	min_dur = roc->duration;
	max_dur = roc->duration;
	type = roc->type;

	list_for_each_entry(tmp, &local->roc_list, list) {
		if (tmp == roc)
			continue;
		if (tmp->sdata != roc->sdata || tmp->chan != roc->chan)
			break;
		max_dur = max(tmp->duration, max_dur);
		min_dur = min(tmp->duration, min_dur);
		type = max(tmp->type, type);
	}

	if (local->ops->remain_on_channel) {
		int ret = drv_remain_on_channel(local, roc->sdata, roc->chan,
						max_dur, type);

		if (ret) {
			wiphy_warn(local->hw.wiphy,
				   "failed to start next HW ROC (%d)\n", ret);
			/*
			 * queue the work struct again to avoid recursion
			 * when multiple failures occur
			 */
			list_for_each_entry(tmp, &local->roc_list, list) {
				if (tmp->sdata != roc->sdata ||
				    tmp->chan != roc->chan)
					break;
				tmp->started = true;
				tmp->abort = true;
			}
			ieee80211_queue_work(&local->hw, &local->hw_roc_done);
			return;
		}

		/* we'll notify about the start once the HW calls back */
		list_for_each_entry(tmp, &local->roc_list, list) {
			if (tmp->sdata != roc->sdata || tmp->chan != roc->chan)
				break;
			tmp->started = true;
		}
	} else {
		/* If actually operating on the desired channel (with at least
		 * 20 MHz channel width) don't stop all the operations but still
		 * treat it as though the ROC operation started properly, so
		 * other ROC operations won't interfere with this one.
		 */
		roc->on_channel = roc->chan == local->_oper_chandef.chan &&
				  local->_oper_chandef.width != NL80211_CHAN_WIDTH_5 &&
				  local->_oper_chandef.width != NL80211_CHAN_WIDTH_10;

		/* start this ROC */
		ieee80211_recalc_idle(local);

		if (!roc->on_channel) {
			ieee80211_offchannel_stop_vifs(local);

			local->tmp_channel = roc->chan;
			ieee80211_hw_config(local, 0);
		}

		ieee80211_queue_delayed_work(&local->hw, &local->roc_work,
					     msecs_to_jiffies(min_dur));

		/* tell userspace or send frame(s) */
		list_for_each_entry(tmp, &local->roc_list, list) {
			if (tmp->sdata != roc->sdata || tmp->chan != roc->chan)
				break;

			tmp->on_channel = roc->on_channel;
			ieee80211_handle_roc_started(tmp, jiffies);
		}
	}
}

void ieee80211_start_next_roc(struct ieee80211_local *local)
{
	struct ieee80211_roc_work *roc;

	lockdep_assert_held(&local->mtx);

	if (list_empty(&local->roc_list)) {
		ieee80211_run_deferred_scan(local);
		return;
	}

	roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
			       list);

	if (WARN_ON_ONCE(roc->started))
		return;

	if (local->ops->remain_on_channel) {
		_ieee80211_start_next_roc(local);
	} else {
		/* delay it a bit */
		ieee80211_queue_delayed_work(&local->hw, &local->roc_work,
					     round_jiffies_relative(HZ/2));
	}
}

static void __ieee80211_roc_work(struct ieee80211_local *local)
{
	struct ieee80211_roc_work *roc;
	bool on_channel;

	lockdep_assert_held(&local->mtx);

	if (WARN_ON(local->ops->remain_on_channel))
		return;

	roc = list_first_entry_or_null(&local->roc_list,
				       struct ieee80211_roc_work, list);
	if (!roc)
		return;

	if (!roc->started) {
		WARN_ON(local->use_chanctx);
		_ieee80211_start_next_roc(local);
	} else {
		on_channel = roc->on_channel;
		if (ieee80211_recalc_sw_work(local, jiffies))
			return;

		/* careful - roc pointer became invalid during recalc */

		if (!on_channel) {
			ieee80211_flush_queues(local, NULL, false);

			local->tmp_channel = NULL;
			ieee80211_hw_config(local, 0);

			ieee80211_offchannel_return(local);
		}

		ieee80211_recalc_idle(local);
		ieee80211_start_next_roc(local);
	}
}

static void ieee80211_roc_work(struct work_struct *work)
{
	struct ieee80211_local *local =
		container_of(work, struct ieee80211_local, roc_work.work);

	mutex_lock(&local->mtx);
	__ieee80211_roc_work(local);
	mutex_unlock(&local->mtx);
}

static void ieee80211_hw_roc_done(struct work_struct *work)
{
	struct ieee80211_local *local =
		container_of(work, struct ieee80211_local, hw_roc_done);

	mutex_lock(&local->mtx);

	ieee80211_end_finished_rocs(local, jiffies);

	/* if there's another roc, start it now */
	ieee80211_start_next_roc(local);

	mutex_unlock(&local->mtx);
}

void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
{
	struct ieee80211_local *local = hw_to_local(hw);

	trace_api_remain_on_channel_expired(local);

	ieee80211_queue_work(hw, &local->hw_roc_done);
}
EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);

static bool
ieee80211_coalesce_hw_started_roc(struct ieee80211_local *local,
				  struct ieee80211_roc_work *new_roc,
				  struct ieee80211_roc_work *cur_roc)
{
	unsigned long now = jiffies;
	unsigned long remaining;

	if (WARN_ON(!cur_roc->started))
		return false;

	/* if it was scheduled in the hardware, but not started yet,
	 * we can only combine if the older one had a longer duration
	 */
	if (!cur_roc->hw_begun && new_roc->duration > cur_roc->duration)
		return false;

	remaining = cur_roc->start_time +
		    msecs_to_jiffies(cur_roc->duration) -
		    now;

	/* if it doesn't fit entirely, schedule a new one */
	if (new_roc->duration > jiffies_to_msecs(remaining))
		return false;

	/* add just after the current one so we combine their finish later */
	list_add(&new_roc->list, &cur_roc->list);

	/* if the existing one has already begun then let this one also
	 * begin, otherwise they'll both be marked properly by the work
	 * struct that runs once the driver notifies us of the beginning
	 */
	if (cur_roc->hw_begun)
		ieee80211_handle_roc_started(new_roc, now);

	return true;
}

static int ieee80211_start_roc_work(struct ieee80211_local *local,
				    struct ieee80211_sub_if_data *sdata,
				    struct ieee80211_channel *channel,
				    unsigned int duration, u64 *cookie,
				    struct sk_buff *txskb,
				    enum ieee80211_roc_type type)
{
	struct ieee80211_roc_work *roc, *tmp;
	bool queued = false, combine_started = true;
	int ret;

	lockdep_assert_held(&local->mtx);

	if (local->use_chanctx && !local->ops->remain_on_channel)
		return -EOPNOTSUPP;

	roc = kzalloc(sizeof(*roc), GFP_KERNEL);
	if (!roc)
		return -ENOMEM;

	/*
	 * If the duration is zero, then the driver
	 * wouldn't actually do anything. Set it to
	 * 10 for now.
	 *
	 * TODO: cancel the off-channel operation
	 *       when we get the SKB's TX status and
	 *       the wait time was zero before.
	 */
	if (!duration)
		duration = 10;

	roc->chan = channel;
	roc->duration = duration;
	roc->req_duration = duration;
	roc->frame = txskb;
	roc->type = type;
	roc->sdata = sdata;

	/*
	 * cookie is either the roc cookie (for normal roc)
	 * or the SKB (for mgmt TX)
	 */
	if (!txskb) {
		roc->cookie = ieee80211_mgmt_tx_cookie(local);
		*cookie = roc->cookie;
	} else {
		roc->mgmt_tx_cookie = *cookie;
	}

	/* if there's no need to queue, handle it immediately */
	if (list_empty(&local->roc_list) &&
	    !local->scanning && !ieee80211_is_radar_required(local)) {
		/* if not HW assist, just queue & schedule work */
		if (!local->ops->remain_on_channel) {
			list_add_tail(&roc->list, &local->roc_list);
			ieee80211_queue_delayed_work(&local->hw,
						     &local->roc_work, 0);
		} else {
			/* otherwise actually kick it off here
			 * (for error handling)
			 */
			ret = drv_remain_on_channel(local, sdata, channel,
						    duration, type);
			if (ret) {
				kfree(roc);
				return ret;
			}
			roc->started = true;
			list_add_tail(&roc->list, &local->roc_list);
		}

		return 0;
	}

	/* otherwise handle queueing */

	list_for_each_entry(tmp, &local->roc_list, list) {
		if (tmp->chan != channel || tmp->sdata != sdata)
			continue;

		/*
		 * Extend this ROC if possible: If it hasn't started, add
		 * just after the new one to combine.
		 */
		if (!tmp->started) {
			list_add(&roc->list, &tmp->list);
			queued = true;
			break;
		}

		if (!combine_started)
			continue;

		if (!local->ops->remain_on_channel) {
			/* If there's no hardware remain-on-channel, and
			 * doing so won't push us over the maximum r-o-c
			 * we allow, then we can just add the new one to
			 * the list and mark it as having started now.
			 * If it would push over the limit, don't try to
			 * combine with other started ones (that haven't
			 * been running as long) but potentially sort it
			 * with others that had the same fate.
			 */
			unsigned long now = jiffies;
			u32 elapsed = jiffies_to_msecs(now - tmp->start_time);
			struct wiphy *wiphy = local->hw.wiphy;
			u32 max_roc = wiphy->max_remain_on_channel_duration;

			if (elapsed + roc->duration > max_roc) {
				combine_started = false;
				continue;
			}

			list_add(&roc->list, &tmp->list);
			queued = true;
			roc->on_channel = tmp->on_channel;
			ieee80211_handle_roc_started(roc, now);
			break;
		}

		queued = ieee80211_coalesce_hw_started_roc(local, roc, tmp);
		if (queued)
			break;
		/* if it wasn't queued, perhaps it can be combined with
		 * another that also couldn't get combined previously,
		 * but no need to check for already started ones, since
		 * that can't work.
		 */
		combine_started = false;
	}

	if (!queued)
		list_add_tail(&roc->list, &local->roc_list);

	return 0;
}

int ieee80211_remain_on_channel(struct wiphy *wiphy, struct wireless_dev *wdev,
				struct ieee80211_channel *chan,
				unsigned int duration, u64 *cookie)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
	struct ieee80211_local *local = sdata->local;
	int ret;

	mutex_lock(&local->mtx);
	ret = ieee80211_start_roc_work(local, sdata, chan,
				       duration, cookie, NULL,
				       IEEE80211_ROC_TYPE_NORMAL);
	mutex_unlock(&local->mtx);

	return ret;
}

static int ieee80211_cancel_roc(struct ieee80211_local *local,
				u64 cookie, bool mgmt_tx)
{
	struct ieee80211_roc_work *roc, *tmp, *found = NULL;
	int ret;

	if (!cookie)
		return -ENOENT;

	mutex_lock(&local->mtx);
	list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
		if (!mgmt_tx && roc->cookie != cookie)
			continue;
		else if (mgmt_tx && roc->mgmt_tx_cookie != cookie)
			continue;

		found = roc;
		break;
	}

	if (!found) {
		mutex_unlock(&local->mtx);
		return -ENOENT;
	}

	if (!found->started) {
		ieee80211_roc_notify_destroy(found);
		goto out_unlock;
	}

	if (local->ops->remain_on_channel) {
		ret = drv_cancel_remain_on_channel(local);
		if (WARN_ON_ONCE(ret)) {
			mutex_unlock(&local->mtx);
			return ret;
		}

		/* TODO:
		 * if multiple items were combined here then we really shouldn't
		 * cancel them all - we should wait for as much time as needed
		 * for the longest remaining one, and only then cancel ...
		 */
		list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
			if (!roc->started)
				break;
			if (roc == found)
				found = NULL;
			ieee80211_roc_notify_destroy(roc);
		}

		/* that really must not happen - it was started */
		WARN_ON(found);

		ieee80211_start_next_roc(local);
	} else {
		/* go through work struct to return to the operating channel */
		found->abort = true;
		mod_delayed_work(local->workqueue, &local->roc_work, 0);
	}

 out_unlock:
	mutex_unlock(&local->mtx);

	return 0;
}

int ieee80211_cancel_remain_on_channel(struct wiphy *wiphy,
				       struct wireless_dev *wdev, u64 cookie)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
	struct ieee80211_local *local = sdata->local;

	return ieee80211_cancel_roc(local, cookie, false);
}

int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
		      struct cfg80211_mgmt_tx_params *params, u64 *cookie)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
	struct ieee80211_local *local = sdata->local;
	struct sk_buff *skb;
	struct sta_info *sta;
	const struct ieee80211_mgmt *mgmt = (void *)params->buf;
	bool need_offchan = false;
	u32 flags;
	int ret;
	u8 *data;

	if (params->dont_wait_for_ack)
		flags = IEEE80211_TX_CTL_NO_ACK;
	else
		flags = IEEE80211_TX_INTFL_NL80211_FRAME_TX |
			IEEE80211_TX_CTL_REQ_TX_STATUS;

	if (params->no_cck)
		flags |= IEEE80211_TX_CTL_NO_CCK_RATE;

	switch (sdata->vif.type) {
	case NL80211_IFTYPE_ADHOC:
		if (!sdata->vif.bss_conf.ibss_joined)
			need_offchan = true;
		/* fall through */
#ifdef CONFIG_MAC80211_MESH
	case NL80211_IFTYPE_MESH_POINT:
		if (ieee80211_vif_is_mesh(&sdata->vif) &&
		    !sdata->u.mesh.mesh_id_len)
			need_offchan = true;
		/* fall through */
#endif
	case NL80211_IFTYPE_AP:
	case NL80211_IFTYPE_AP_VLAN:
	case NL80211_IFTYPE_P2P_GO:
		if (sdata->vif.type != NL80211_IFTYPE_ADHOC &&
		    !ieee80211_vif_is_mesh(&sdata->vif) &&
		    !rcu_access_pointer(sdata->bss->beacon))
			need_offchan = true;
		if (!ieee80211_is_action(mgmt->frame_control) ||
		    mgmt->u.action.category == WLAN_CATEGORY_PUBLIC ||
		    mgmt->u.action.category == WLAN_CATEGORY_SELF_PROTECTED ||
		    mgmt->u.action.category == WLAN_CATEGORY_SPECTRUM_MGMT)
			break;
		rcu_read_lock();
		sta = sta_info_get(sdata, mgmt->da);
		rcu_read_unlock();
		if (!sta)
			return -ENOLINK;
		break;
	case NL80211_IFTYPE_STATION:
	case NL80211_IFTYPE_P2P_CLIENT:
		sdata_lock(sdata);
		if (!sdata->u.mgd.associated ||
		    (params->offchan && params->wait &&
		     local->ops->remain_on_channel &&
		     memcmp(sdata->u.mgd.associated->bssid,
			    mgmt->bssid, ETH_ALEN)))
			need_offchan = true;
		sdata_unlock(sdata);
		break;
	case NL80211_IFTYPE_P2P_DEVICE:
		need_offchan = true;
		break;
	default:
		return -EOPNOTSUPP;
	}

	/* configurations requiring offchan cannot work if no channel has been
	 * specified
	 */
	if (need_offchan && !params->chan)
		return -EINVAL;

	mutex_lock(&local->mtx);

	/* Check if the operating channel is the requested channel */
	if (!need_offchan) {
		struct ieee80211_chanctx_conf *chanctx_conf;

		rcu_read_lock();
		chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);

		if (chanctx_conf) {
			need_offchan = params->chan &&
				       (params->chan !=
					chanctx_conf->def.chan);
		} else if (!params->chan) {
			ret = -EINVAL;
			rcu_read_unlock();
			goto out_unlock;
		} else {
			need_offchan = true;
		}
		rcu_read_unlock();
	}

	if (need_offchan && !params->offchan) {
		ret = -EBUSY;
		goto out_unlock;
	}

	skb = dev_alloc_skb(local->hw.extra_tx_headroom + params->len);
	if (!skb) {
		ret = -ENOMEM;
		goto out_unlock;
	}
	skb_reserve(skb, local->hw.extra_tx_headroom);

	data = skb_put(skb, params->len);
	memcpy(data, params->buf, params->len);

	/* Update CSA counters */
	if (sdata->vif.csa_active &&
	    (sdata->vif.type == NL80211_IFTYPE_AP ||
	     sdata->vif.type == NL80211_IFTYPE_MESH_POINT ||
	     sdata->vif.type == NL80211_IFTYPE_ADHOC) &&
	    params->n_csa_offsets) {
		int i;
		struct beacon_data *beacon = NULL;

		rcu_read_lock();

		if (sdata->vif.type == NL80211_IFTYPE_AP)
			beacon = rcu_dereference(sdata->u.ap.beacon);
		else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
			beacon = rcu_dereference(sdata->u.ibss.presp);
		else if (ieee80211_vif_is_mesh(&sdata->vif))
			beacon = rcu_dereference(sdata->u.mesh.beacon);

		if (beacon)
			for (i = 0; i < params->n_csa_offsets; i++)
				data[params->csa_offsets[i]] =
					beacon->csa_current_counter;

		rcu_read_unlock();
	}

	IEEE80211_SKB_CB(skb)->flags = flags;

	skb->dev = sdata->dev;

	if (!params->dont_wait_for_ack) {
		/* make a copy to preserve the frame contents
		 * in case of encryption.
		 */
		ret = ieee80211_attach_ack_skb(local, skb, cookie, GFP_KERNEL);
		if (ret) {
			kfree_skb(skb);
			goto out_unlock;
		}
	} else {
		/* Assign a dummy non-zero cookie, it's not sent to
		 * userspace in this case but we rely on its value
		 * internally in the need_offchan case to distinguish
		 * mgmt-tx from remain-on-channel.
		 */
		*cookie = 0xffffffff;
	}

	if (!need_offchan) {
		ieee80211_tx_skb(sdata, skb);
		ret = 0;
		goto out_unlock;
	}

	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_TX_OFFCHAN |
					IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
	if (ieee80211_hw_check(&local->hw, QUEUE_CONTROL))
		IEEE80211_SKB_CB(skb)->hw_queue =
			local->hw.offchannel_tx_hw_queue;

	/* This will handle all kinds of coalescing and immediate TX */
	ret = ieee80211_start_roc_work(local, sdata, params->chan,
				       params->wait, cookie, skb,
				       IEEE80211_ROC_TYPE_MGMT_TX);
	if (ret)
		ieee80211_free_txskb(&local->hw, skb);
 out_unlock:
	mutex_unlock(&local->mtx);
	return ret;
}

int ieee80211_mgmt_tx_cancel_wait(struct wiphy *wiphy,
				  struct wireless_dev *wdev, u64 cookie)
{
	struct ieee80211_local *local = wiphy_priv(wiphy);

	return ieee80211_cancel_roc(local, cookie, true);
}

void ieee80211_roc_setup(struct ieee80211_local *local)
{
	INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
	INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
	INIT_DELAYED_WORK(&local->roc_work, ieee80211_roc_work);
	INIT_LIST_HEAD(&local->roc_list);
}

void ieee80211_roc_purge(struct ieee80211_local *local,
			 struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_roc_work *roc, *tmp;
	bool work_to_do = false;

	mutex_lock(&local->mtx);
	list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
		if (sdata && roc->sdata != sdata)
			continue;

		if (roc->started) {
			if (local->ops->remain_on_channel) {
				/* can race, so ignore return value */
				drv_cancel_remain_on_channel(local);
				ieee80211_roc_notify_destroy(roc);
			} else {
				roc->abort = true;
				work_to_do = true;
			}
		} else {
			ieee80211_roc_notify_destroy(roc);
		}
	}
	if (work_to_do)
		__ieee80211_roc_work(local);
	mutex_unlock(&local->mtx);
}