Free Electrons

Embedded Linux Experts

  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
/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2008-2010	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 <linux/etherdevice.h>
#include <net/mac80211.h>
#include <asm/unaligned.h>
#include "ieee80211_i.h"
#include "rate.h"
#include "mesh.h"
#include "led.h"
#include "wme.h"


void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
				 struct sk_buff *skb)
{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	int tmp;

	skb->pkt_type = IEEE80211_TX_STATUS_MSG;
	skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
		       &local->skb_queue : &local->skb_queue_unreliable, skb);
	tmp = skb_queue_len(&local->skb_queue) +
		skb_queue_len(&local->skb_queue_unreliable);
	while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
	       (skb = skb_dequeue(&local->skb_queue_unreliable))) {
		ieee80211_free_txskb(hw, skb);
		tmp--;
		I802_DEBUG_INC(local->tx_status_drop);
	}
	tasklet_schedule(&local->tasklet);
}
EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);

static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
					    struct sta_info *sta,
					    struct sk_buff *skb)
{
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	struct ieee80211_hdr *hdr = (void *)skb->data;
	int ac;

	/*
	 * This skb 'survived' a round-trip through the driver, and
	 * hopefully the driver didn't mangle it too badly. However,
	 * we can definitely not rely on the control information
	 * being correct. Clear it so we don't get junk there, and
	 * indicate that it needs new processing, but must not be
	 * modified/encrypted again.
	 */
	memset(&info->control, 0, sizeof(info->control));

	info->control.jiffies = jiffies;
	info->control.vif = &sta->sdata->vif;
	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING |
		       IEEE80211_TX_INTFL_RETRANSMISSION;
	info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;

	sta->tx_filtered_count++;

	/*
	 * Clear more-data bit on filtered frames, it might be set
	 * but later frames might time out so it might have to be
	 * clear again ... It's all rather unlikely (this frame
	 * should time out first, right?) but let's not confuse
	 * peers unnecessarily.
	 */
	if (hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_MOREDATA))
		hdr->frame_control &= ~cpu_to_le16(IEEE80211_FCTL_MOREDATA);

	if (ieee80211_is_data_qos(hdr->frame_control)) {
		u8 *p = ieee80211_get_qos_ctl(hdr);
		int tid = *p & IEEE80211_QOS_CTL_TID_MASK;

		/*
		 * Clear EOSP if set, this could happen e.g.
		 * if an absence period (us being a P2P GO)
		 * shortens the SP.
		 */
		if (*p & IEEE80211_QOS_CTL_EOSP)
			*p &= ~IEEE80211_QOS_CTL_EOSP;
		ac = ieee802_1d_to_ac[tid & 7];
	} else {
		ac = IEEE80211_AC_BE;
	}

	/*
	 * Clear the TX filter mask for this STA when sending the next
	 * packet. If the STA went to power save mode, this will happen
	 * when it wakes up for the next time.
	 */
	set_sta_flag(sta, WLAN_STA_CLEAR_PS_FILT);

	/*
	 * This code races in the following way:
	 *
	 *  (1) STA sends frame indicating it will go to sleep and does so
	 *  (2) hardware/firmware adds STA to filter list, passes frame up
	 *  (3) hardware/firmware processes TX fifo and suppresses a frame
	 *  (4) we get TX status before having processed the frame and
	 *	knowing that the STA has gone to sleep.
	 *
	 * This is actually quite unlikely even when both those events are
	 * processed from interrupts coming in quickly after one another or
	 * even at the same time because we queue both TX status events and
	 * RX frames to be processed by a tasklet and process them in the
	 * same order that they were received or TX status last. Hence, there
	 * is no race as long as the frame RX is processed before the next TX
	 * status, which drivers can ensure, see below.
	 *
	 * Note that this can only happen if the hardware or firmware can
	 * actually add STAs to the filter list, if this is done by the
	 * driver in response to set_tim() (which will only reduce the race
	 * this whole filtering tries to solve, not completely solve it)
	 * this situation cannot happen.
	 *
	 * To completely solve this race drivers need to make sure that they
	 *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
	 *	functions and
	 *  (b) always process RX events before TX status events if ordering
	 *      can be unknown, for example with different interrupt status
	 *	bits.
	 *  (c) if PS mode transitions are manual (i.e. the flag
	 *      %IEEE80211_HW_AP_LINK_PS is set), always process PS state
	 *      changes before calling TX status events if ordering can be
	 *	unknown.
	 */
	if (test_sta_flag(sta, WLAN_STA_PS_STA) &&
	    skb_queue_len(&sta->tx_filtered[ac]) < STA_MAX_TX_BUFFER) {
		skb_queue_tail(&sta->tx_filtered[ac], skb);
		sta_info_recalc_tim(sta);

		if (!timer_pending(&local->sta_cleanup))
			mod_timer(&local->sta_cleanup,
				  round_jiffies(jiffies +
						STA_INFO_CLEANUP_INTERVAL));
		return;
	}

	if (!test_sta_flag(sta, WLAN_STA_PS_STA) &&
	    !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
		/* Software retry the packet once */
		info->flags |= IEEE80211_TX_INTFL_RETRIED;
		ieee80211_add_pending_skb(local, skb);
		return;
	}

	ps_dbg_ratelimited(sta->sdata,
			   "dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
			   skb_queue_len(&sta->tx_filtered[ac]),
			   !!test_sta_flag(sta, WLAN_STA_PS_STA), jiffies);
	ieee80211_free_txskb(&local->hw, skb);
}

static void ieee80211_check_pending_bar(struct sta_info *sta, u8 *addr, u8 tid)
{
	struct tid_ampdu_tx *tid_tx;

	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
	if (!tid_tx || !tid_tx->bar_pending)
		return;

	tid_tx->bar_pending = false;
	ieee80211_send_bar(&sta->sdata->vif, addr, tid, tid_tx->failed_bar_ssn);
}

static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
{
	struct ieee80211_mgmt *mgmt = (void *) skb->data;
	struct ieee80211_local *local = sta->local;
	struct ieee80211_sub_if_data *sdata = sta->sdata;

	if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS)
		sta->last_rx = jiffies;

	if (ieee80211_is_data_qos(mgmt->frame_control)) {
		struct ieee80211_hdr *hdr = (void *) skb->data;
		u8 *qc = ieee80211_get_qos_ctl(hdr);
		u16 tid = qc[0] & 0xf;

		ieee80211_check_pending_bar(sta, hdr->addr1, tid);
	}

	if (ieee80211_is_action(mgmt->frame_control) &&
	    mgmt->u.action.category == WLAN_CATEGORY_HT &&
	    mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS &&
	    sdata->vif.type == NL80211_IFTYPE_STATION &&
	    ieee80211_sdata_running(sdata)) {
		/*
		 * This update looks racy, but isn't -- if we come
		 * here we've definitely got a station that we're
		 * talking to, and on a managed interface that can
		 * only be the AP. And the only other place updating
		 * this variable in managed mode is before association.
		 */
		switch (mgmt->u.action.u.ht_smps.smps_control) {
		case WLAN_HT_SMPS_CONTROL_DYNAMIC:
			sdata->smps_mode = IEEE80211_SMPS_DYNAMIC;
			break;
		case WLAN_HT_SMPS_CONTROL_STATIC:
			sdata->smps_mode = IEEE80211_SMPS_STATIC;
			break;
		case WLAN_HT_SMPS_CONTROL_DISABLED:
		default: /* shouldn't happen since we don't send that */
			sdata->smps_mode = IEEE80211_SMPS_OFF;
			break;
		}

		ieee80211_queue_work(&local->hw, &sdata->recalc_smps);
	}
}

static void ieee80211_set_bar_pending(struct sta_info *sta, u8 tid, u16 ssn)
{
	struct tid_ampdu_tx *tid_tx;

	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
	if (!tid_tx)
		return;

	tid_tx->failed_bar_ssn = ssn;
	tid_tx->bar_pending = true;
}

static int ieee80211_tx_radiotap_len(struct ieee80211_tx_info *info)
{
	int len = sizeof(struct ieee80211_radiotap_header);

	/* IEEE80211_RADIOTAP_RATE rate */
	if (info->status.rates[0].idx >= 0 &&
	    !(info->status.rates[0].flags & (IEEE80211_TX_RC_MCS |
					     IEEE80211_TX_RC_VHT_MCS)))
		len += 2;

	/* IEEE80211_RADIOTAP_TX_FLAGS */
	len += 2;

	/* IEEE80211_RADIOTAP_DATA_RETRIES */
	len += 1;

	/* IEEE80211_RADIOTAP_MCS
	 * IEEE80211_RADIOTAP_VHT */
	if (info->status.rates[0].idx >= 0) {
		if (info->status.rates[0].flags & IEEE80211_TX_RC_MCS)
			len += 3;
		else if (info->status.rates[0].flags & IEEE80211_TX_RC_VHT_MCS)
			len = ALIGN(len, 2) + 12;
	}

	return len;
}

static void
ieee80211_add_tx_radiotap_header(struct ieee80211_local *local,
				 struct ieee80211_supported_band *sband,
				 struct sk_buff *skb, int retry_count,
				 int rtap_len, int shift)
{
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
	struct ieee80211_radiotap_header *rthdr;
	unsigned char *pos;
	u16 txflags;

	rthdr = (struct ieee80211_radiotap_header *) skb_push(skb, rtap_len);

	memset(rthdr, 0, rtap_len);
	rthdr->it_len = cpu_to_le16(rtap_len);
	rthdr->it_present =
		cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
			    (1 << IEEE80211_RADIOTAP_DATA_RETRIES));
	pos = (unsigned char *)(rthdr + 1);

	/*
	 * XXX: Once radiotap gets the bitmap reset thing the vendor
	 *	extensions proposal contains, we can actually report
	 *	the whole set of tries we did.
	 */

	/* IEEE80211_RADIOTAP_RATE */
	if (info->status.rates[0].idx >= 0 &&
	    !(info->status.rates[0].flags & (IEEE80211_TX_RC_MCS |
					     IEEE80211_TX_RC_VHT_MCS))) {
		u16 rate;

		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
		rate = sband->bitrates[info->status.rates[0].idx].bitrate;
		*pos = DIV_ROUND_UP(rate, 5 * (1 << shift));
		/* padding for tx flags */
		pos += 2;
	}

	/* IEEE80211_RADIOTAP_TX_FLAGS */
	txflags = 0;
	if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
	    !is_multicast_ether_addr(hdr->addr1))
		txflags |= IEEE80211_RADIOTAP_F_TX_FAIL;

	if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
	    (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
		txflags |= IEEE80211_RADIOTAP_F_TX_CTS;
	else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
		txflags |= IEEE80211_RADIOTAP_F_TX_RTS;

	put_unaligned_le16(txflags, pos);
	pos += 2;

	/* IEEE80211_RADIOTAP_DATA_RETRIES */
	/* for now report the total retry_count */
	*pos = retry_count;
	pos++;

	if (info->status.rates[0].idx < 0)
		return;

	/* IEEE80211_RADIOTAP_MCS
	 * IEEE80211_RADIOTAP_VHT */
	if (info->status.rates[0].flags & IEEE80211_TX_RC_MCS) {
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
		pos[0] = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
			 IEEE80211_RADIOTAP_MCS_HAVE_GI |
			 IEEE80211_RADIOTAP_MCS_HAVE_BW;
		if (info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
			pos[1] |= IEEE80211_RADIOTAP_MCS_SGI;
		if (info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
			pos[1] |= IEEE80211_RADIOTAP_MCS_BW_40;
		if (info->status.rates[0].flags & IEEE80211_TX_RC_GREEN_FIELD)
			pos[1] |= IEEE80211_RADIOTAP_MCS_FMT_GF;
		pos[2] = info->status.rates[0].idx;
		pos += 3;
	} else if (info->status.rates[0].flags & IEEE80211_TX_RC_VHT_MCS) {
		u16 known = local->hw.radiotap_vht_details &
			(IEEE80211_RADIOTAP_VHT_KNOWN_GI |
			 IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH);

		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_VHT);

		/* required alignment from rthdr */
		pos = (u8 *)rthdr + ALIGN(pos - (u8 *)rthdr, 2);

		/* u16 known - IEEE80211_RADIOTAP_VHT_KNOWN_* */
		put_unaligned_le16(known, pos);
		pos += 2;

		/* u8 flags - IEEE80211_RADIOTAP_VHT_FLAG_* */
		if (info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
			*pos |= IEEE80211_RADIOTAP_VHT_FLAG_SGI;
		pos++;

		/* u8 bandwidth */
		if (info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
			*pos = 1;
		else if (info->status.rates[0].flags & IEEE80211_TX_RC_80_MHZ_WIDTH)
			*pos = 4;
		else if (info->status.rates[0].flags & IEEE80211_TX_RC_160_MHZ_WIDTH)
			*pos = 11;
		else /* IEEE80211_TX_RC_{20_MHZ_WIDTH,FIXME:DUP_DATA} */
			*pos = 0;
		pos++;

		/* u8 mcs_nss[4] */
		*pos = (ieee80211_rate_get_vht_mcs(&info->status.rates[0]) << 4) |
			ieee80211_rate_get_vht_nss(&info->status.rates[0]);
		pos += 4;

		/* u8 coding */
		pos++;
		/* u8 group_id */
		pos++;
		/* u16 partial_aid */
		pos += 2;
	}
}

static void ieee80211_report_used_skb(struct ieee80211_local *local,
				      struct sk_buff *skb, bool dropped)
{
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	struct ieee80211_hdr *hdr = (void *)skb->data;
	bool acked = info->flags & IEEE80211_TX_STAT_ACK;

	if (dropped)
		acked = false;

	if (info->flags & (IEEE80211_TX_INTFL_NL80211_FRAME_TX |
			   IEEE80211_TX_INTFL_MLME_CONN_TX)) {
		struct ieee80211_sub_if_data *sdata = NULL;
		struct ieee80211_sub_if_data *iter_sdata;
		u64 cookie = (unsigned long)skb;

		rcu_read_lock();

		if (skb->dev) {
			list_for_each_entry_rcu(iter_sdata, &local->interfaces,
						list) {
				if (!iter_sdata->dev)
					continue;

				if (skb->dev == iter_sdata->dev) {
					sdata = iter_sdata;
					break;
				}
			}
		} else {
			sdata = rcu_dereference(local->p2p_sdata);
		}

		if (!sdata) {
			skb->dev = NULL;
		} else if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) {
			ieee80211_mgd_conn_tx_status(sdata, hdr->frame_control,
						     acked);
		} else if (ieee80211_is_nullfunc(hdr->frame_control) ||
			   ieee80211_is_qos_nullfunc(hdr->frame_control)) {
			cfg80211_probe_status(sdata->dev, hdr->addr1,
					      cookie, acked, GFP_ATOMIC);
		} else {
			cfg80211_mgmt_tx_status(&sdata->wdev, cookie, skb->data,
						skb->len, acked, GFP_ATOMIC);
		}

		rcu_read_unlock();
	}

	if (unlikely(info->ack_frame_id)) {
		struct sk_buff *ack_skb;
		unsigned long flags;

		spin_lock_irqsave(&local->ack_status_lock, flags);
		ack_skb = idr_find(&local->ack_status_frames,
				   info->ack_frame_id);
		if (ack_skb)
			idr_remove(&local->ack_status_frames,
				   info->ack_frame_id);
		spin_unlock_irqrestore(&local->ack_status_lock, flags);

		if (ack_skb) {
			if (!dropped) {
				/* consumes ack_skb */
				skb_complete_wifi_ack(ack_skb, acked);
			} else {
				dev_kfree_skb_any(ack_skb);
			}
		}
	}
}

/*
 * Use a static threshold for now, best value to be determined
 * by testing ...
 * Should it depend on:
 *  - on # of retransmissions
 *  - current throughput (higher value for higher tpt)?
 */
#define STA_LOST_PKT_THRESHOLD	50

void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
{
	struct sk_buff *skb2;
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	__le16 fc;
	struct ieee80211_supported_band *sband;
	struct ieee80211_sub_if_data *sdata;
	struct net_device *prev_dev = NULL;
	struct sta_info *sta, *tmp;
	int retry_count = -1, i;
	int rates_idx = -1;
	bool send_to_cooked;
	bool acked;
	struct ieee80211_bar *bar;
	int rtap_len;
	int shift = 0;

	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
		if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
		    !(info->flags & IEEE80211_TX_STAT_AMPDU)) {
			/* just the first aggr frame carry status info */
			info->status.rates[i].idx = -1;
			info->status.rates[i].count = 0;
			break;
		} else if (info->status.rates[i].idx < 0) {
			break;
		} else if (i >= hw->max_report_rates) {
			/* the HW cannot have attempted that rate */
			info->status.rates[i].idx = -1;
			info->status.rates[i].count = 0;
			break;
		}

		retry_count += info->status.rates[i].count;
	}
	rates_idx = i - 1;

	if (retry_count < 0)
		retry_count = 0;

	rcu_read_lock();

	sband = local->hw.wiphy->bands[info->band];
	fc = hdr->frame_control;

	for_each_sta_info(local, hdr->addr1, sta, tmp) {
		/* skip wrong virtual interface */
		if (!ether_addr_equal(hdr->addr2, sta->sdata->vif.addr))
			continue;

		shift = ieee80211_vif_get_shift(&sta->sdata->vif);

		if (info->flags & IEEE80211_TX_STATUS_EOSP)
			clear_sta_flag(sta, WLAN_STA_SP);

		acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
		if (!acked && test_sta_flag(sta, WLAN_STA_PS_STA)) {
			/*
			 * The STA is in power save mode, so assume
			 * that this TX packet failed because of that.
			 */
			ieee80211_handle_filtered_frame(local, sta, skb);
			rcu_read_unlock();
			return;
		}

		/* mesh Peer Service Period support */
		if (ieee80211_vif_is_mesh(&sta->sdata->vif) &&
		    ieee80211_is_data_qos(fc))
			ieee80211_mpsp_trigger_process(
					ieee80211_get_qos_ctl(hdr),
					sta, true, acked);

		if ((local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) &&
		    (rates_idx != -1))
			sta->last_tx_rate = info->status.rates[rates_idx];

		if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
		    (ieee80211_is_data_qos(fc))) {
			u16 tid, ssn;
			u8 *qc;

			qc = ieee80211_get_qos_ctl(hdr);
			tid = qc[0] & 0xf;
			ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
						& IEEE80211_SCTL_SEQ);
			ieee80211_send_bar(&sta->sdata->vif, hdr->addr1,
					   tid, ssn);
		}

		if (!acked && ieee80211_is_back_req(fc)) {
			u16 tid, control;

			/*
			 * BAR failed, store the last SSN and retry sending
			 * the BAR when the next unicast transmission on the
			 * same TID succeeds.
			 */
			bar = (struct ieee80211_bar *) skb->data;
			control = le16_to_cpu(bar->control);
			if (!(control & IEEE80211_BAR_CTRL_MULTI_TID)) {
				u16 ssn = le16_to_cpu(bar->start_seq_num);

				tid = (control &
				       IEEE80211_BAR_CTRL_TID_INFO_MASK) >>
				      IEEE80211_BAR_CTRL_TID_INFO_SHIFT;

				ieee80211_set_bar_pending(sta, tid, ssn);
			}
		}

		if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
			ieee80211_handle_filtered_frame(local, sta, skb);
			rcu_read_unlock();
			return;
		} else {
			if (!acked)
				sta->tx_retry_failed++;
			sta->tx_retry_count += retry_count;
		}

		rate_control_tx_status(local, sband, sta, skb);
		if (ieee80211_vif_is_mesh(&sta->sdata->vif))
			ieee80211s_update_metric(local, sta, skb);

		if (!(info->flags & IEEE80211_TX_CTL_INJECTED) && acked)
			ieee80211_frame_acked(sta, skb);

		if ((sta->sdata->vif.type == NL80211_IFTYPE_STATION) &&
		    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS))
			ieee80211_sta_tx_notify(sta->sdata, (void *) skb->data, acked);

		if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) {
			if (info->flags & IEEE80211_TX_STAT_ACK) {
				if (sta->lost_packets)
					sta->lost_packets = 0;
			} else if (++sta->lost_packets >= STA_LOST_PKT_THRESHOLD) {
				cfg80211_cqm_pktloss_notify(sta->sdata->dev,
							    sta->sta.addr,
							    sta->lost_packets,
							    GFP_ATOMIC);
				sta->lost_packets = 0;
			}
		}

		if (acked)
			sta->last_ack_signal = info->status.ack_signal;
	}

	rcu_read_unlock();

	ieee80211_led_tx(local);

	/* SNMP counters
	 * Fragments are passed to low-level drivers as separate skbs, so these
	 * are actually fragments, not frames. Update frame counters only for
	 * the first fragment of the frame. */
	if (info->flags & IEEE80211_TX_STAT_ACK) {
		if (ieee80211_is_first_frag(hdr->seq_ctrl)) {
			local->dot11TransmittedFrameCount++;
			if (is_multicast_ether_addr(hdr->addr1))
				local->dot11MulticastTransmittedFrameCount++;
			if (retry_count > 0)
				local->dot11RetryCount++;
			if (retry_count > 1)
				local->dot11MultipleRetryCount++;
		}

		/* This counter shall be incremented for an acknowledged MPDU
		 * with an individual address in the address 1 field or an MPDU
		 * with a multicast address in the address 1 field of type Data
		 * or Management. */
		if (!is_multicast_ether_addr(hdr->addr1) ||
		    ieee80211_is_data(fc) ||
		    ieee80211_is_mgmt(fc))
			local->dot11TransmittedFragmentCount++;
	} else {
		if (ieee80211_is_first_frag(hdr->seq_ctrl))
			local->dot11FailedCount++;
	}

	if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
	    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) &&
	    !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
	    local->ps_sdata && !(local->scanning)) {
		if (info->flags & IEEE80211_TX_STAT_ACK) {
			local->ps_sdata->u.mgd.flags |=
					IEEE80211_STA_NULLFUNC_ACKED;
		} else
			mod_timer(&local->dynamic_ps_timer, jiffies +
					msecs_to_jiffies(10));
	}

	ieee80211_report_used_skb(local, skb, false);

	/* this was a transmitted frame, but now we want to reuse it */
	skb_orphan(skb);

	/* Need to make a copy before skb->cb gets cleared */
	send_to_cooked = !!(info->flags & IEEE80211_TX_CTL_INJECTED) ||
			 !(ieee80211_is_data(fc));

	/*
	 * This is a bit racy but we can avoid a lot of work
	 * with this test...
	 */
	if (!local->monitors && (!send_to_cooked || !local->cooked_mntrs)) {
		dev_kfree_skb(skb);
		return;
	}

	/* send frame to monitor interfaces now */
	rtap_len = ieee80211_tx_radiotap_len(info);
	if (WARN_ON_ONCE(skb_headroom(skb) < rtap_len)) {
		pr_err("ieee80211_tx_status: headroom too small\n");
		dev_kfree_skb(skb);
		return;
	}
	ieee80211_add_tx_radiotap_header(local, sband, skb, retry_count,
					 rtap_len, shift);

	/* XXX: is this sufficient for BPF? */
	skb_set_mac_header(skb, 0);
	skb->ip_summed = CHECKSUM_UNNECESSARY;
	skb->pkt_type = PACKET_OTHERHOST;
	skb->protocol = htons(ETH_P_802_2);
	memset(skb->cb, 0, sizeof(skb->cb));

	rcu_read_lock();
	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
		if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
			if (!ieee80211_sdata_running(sdata))
				continue;

			if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
			    !send_to_cooked)
				continue;

			if (prev_dev) {
				skb2 = skb_clone(skb, GFP_ATOMIC);
				if (skb2) {
					skb2->dev = prev_dev;
					netif_rx(skb2);
				}
			}

			prev_dev = sdata->dev;
		}
	}
	if (prev_dev) {
		skb->dev = prev_dev;
		netif_rx(skb);
		skb = NULL;
	}
	rcu_read_unlock();
	dev_kfree_skb(skb);
}
EXPORT_SYMBOL(ieee80211_tx_status);

void ieee80211_report_low_ack(struct ieee80211_sta *pubsta, u32 num_packets)
{
	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
	cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
				    num_packets, GFP_ATOMIC);
}
EXPORT_SYMBOL(ieee80211_report_low_ack);

void ieee80211_free_txskb(struct ieee80211_hw *hw, struct sk_buff *skb)
{
	struct ieee80211_local *local = hw_to_local(hw);

	ieee80211_report_used_skb(local, skb, true);
	dev_kfree_skb_any(skb);
}
EXPORT_SYMBOL(ieee80211_free_txskb);

void ieee80211_purge_tx_queue(struct ieee80211_hw *hw,
			      struct sk_buff_head *skbs)
{
	struct sk_buff *skb;

	while ((skb = __skb_dequeue(skbs)))
		ieee80211_free_txskb(hw, skb);
}