xref: /openbmc/linux/net/mac80211/status.c (revision 74ca4313)
1 /*
2  * Copyright 2002-2005, Instant802 Networks, Inc.
3  * Copyright 2005-2006, Devicescape Software, Inc.
4  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
5  * Copyright 2008-2010	Johannes Berg <johannes@sipsolutions.net>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 
12 #include <linux/export.h>
13 #include <linux/etherdevice.h>
14 #include <net/mac80211.h>
15 #include <asm/unaligned.h>
16 #include "ieee80211_i.h"
17 #include "rate.h"
18 #include "mesh.h"
19 #include "led.h"
20 #include "wme.h"
21 
22 
23 void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
24 				 struct sk_buff *skb)
25 {
26 	struct ieee80211_local *local = hw_to_local(hw);
27 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
28 	int tmp;
29 
30 	skb->pkt_type = IEEE80211_TX_STATUS_MSG;
31 	skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
32 		       &local->skb_queue : &local->skb_queue_unreliable, skb);
33 	tmp = skb_queue_len(&local->skb_queue) +
34 		skb_queue_len(&local->skb_queue_unreliable);
35 	while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
36 	       (skb = skb_dequeue(&local->skb_queue_unreliable))) {
37 		dev_kfree_skb_irq(skb);
38 		tmp--;
39 		I802_DEBUG_INC(local->tx_status_drop);
40 	}
41 	tasklet_schedule(&local->tasklet);
42 }
43 EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);
44 
45 static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
46 					    struct sta_info *sta,
47 					    struct sk_buff *skb)
48 {
49 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
50 	struct ieee80211_hdr *hdr = (void *)skb->data;
51 	int ac;
52 
53 	/*
54 	 * This skb 'survived' a round-trip through the driver, and
55 	 * hopefully the driver didn't mangle it too badly. However,
56 	 * we can definitely not rely on the control information
57 	 * being correct. Clear it so we don't get junk there, and
58 	 * indicate that it needs new processing, but must not be
59 	 * modified/encrypted again.
60 	 */
61 	memset(&info->control, 0, sizeof(info->control));
62 
63 	info->control.jiffies = jiffies;
64 	info->control.vif = &sta->sdata->vif;
65 	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING |
66 		       IEEE80211_TX_INTFL_RETRANSMISSION;
67 	info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;
68 
69 	sta->tx_filtered_count++;
70 
71 	/*
72 	 * Clear more-data bit on filtered frames, it might be set
73 	 * but later frames might time out so it might have to be
74 	 * clear again ... It's all rather unlikely (this frame
75 	 * should time out first, right?) but let's not confuse
76 	 * peers unnecessarily.
77 	 */
78 	if (hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_MOREDATA))
79 		hdr->frame_control &= ~cpu_to_le16(IEEE80211_FCTL_MOREDATA);
80 
81 	if (ieee80211_is_data_qos(hdr->frame_control)) {
82 		u8 *p = ieee80211_get_qos_ctl(hdr);
83 		int tid = *p & IEEE80211_QOS_CTL_TID_MASK;
84 
85 		/*
86 		 * Clear EOSP if set, this could happen e.g.
87 		 * if an absence period (us being a P2P GO)
88 		 * shortens the SP.
89 		 */
90 		if (*p & IEEE80211_QOS_CTL_EOSP)
91 			*p &= ~IEEE80211_QOS_CTL_EOSP;
92 		ac = ieee802_1d_to_ac[tid & 7];
93 	} else {
94 		ac = IEEE80211_AC_BE;
95 	}
96 
97 	/*
98 	 * Clear the TX filter mask for this STA when sending the next
99 	 * packet. If the STA went to power save mode, this will happen
100 	 * when it wakes up for the next time.
101 	 */
102 	set_sta_flag(sta, WLAN_STA_CLEAR_PS_FILT);
103 
104 	/*
105 	 * This code races in the following way:
106 	 *
107 	 *  (1) STA sends frame indicating it will go to sleep and does so
108 	 *  (2) hardware/firmware adds STA to filter list, passes frame up
109 	 *  (3) hardware/firmware processes TX fifo and suppresses a frame
110 	 *  (4) we get TX status before having processed the frame and
111 	 *	knowing that the STA has gone to sleep.
112 	 *
113 	 * This is actually quite unlikely even when both those events are
114 	 * processed from interrupts coming in quickly after one another or
115 	 * even at the same time because we queue both TX status events and
116 	 * RX frames to be processed by a tasklet and process them in the
117 	 * same order that they were received or TX status last. Hence, there
118 	 * is no race as long as the frame RX is processed before the next TX
119 	 * status, which drivers can ensure, see below.
120 	 *
121 	 * Note that this can only happen if the hardware or firmware can
122 	 * actually add STAs to the filter list, if this is done by the
123 	 * driver in response to set_tim() (which will only reduce the race
124 	 * this whole filtering tries to solve, not completely solve it)
125 	 * this situation cannot happen.
126 	 *
127 	 * To completely solve this race drivers need to make sure that they
128 	 *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
129 	 *	functions and
130 	 *  (b) always process RX events before TX status events if ordering
131 	 *      can be unknown, for example with different interrupt status
132 	 *	bits.
133 	 *  (c) if PS mode transitions are manual (i.e. the flag
134 	 *      %IEEE80211_HW_AP_LINK_PS is set), always process PS state
135 	 *      changes before calling TX status events if ordering can be
136 	 *	unknown.
137 	 */
138 	if (test_sta_flag(sta, WLAN_STA_PS_STA) &&
139 	    skb_queue_len(&sta->tx_filtered[ac]) < STA_MAX_TX_BUFFER) {
140 		skb_queue_tail(&sta->tx_filtered[ac], skb);
141 		sta_info_recalc_tim(sta);
142 
143 		if (!timer_pending(&local->sta_cleanup))
144 			mod_timer(&local->sta_cleanup,
145 				  round_jiffies(jiffies +
146 						STA_INFO_CLEANUP_INTERVAL));
147 		return;
148 	}
149 
150 	if (!test_sta_flag(sta, WLAN_STA_PS_STA) &&
151 	    !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
152 		/* Software retry the packet once */
153 		info->flags |= IEEE80211_TX_INTFL_RETRIED;
154 		ieee80211_add_pending_skb(local, skb);
155 		return;
156 	}
157 
158 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
159 	if (net_ratelimit())
160 		wiphy_debug(local->hw.wiphy,
161 			    "dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
162 			    skb_queue_len(&sta->tx_filtered[ac]),
163 			    !!test_sta_flag(sta, WLAN_STA_PS_STA), jiffies);
164 #endif
165 	dev_kfree_skb(skb);
166 }
167 
168 static void ieee80211_check_pending_bar(struct sta_info *sta, u8 *addr, u8 tid)
169 {
170 	struct tid_ampdu_tx *tid_tx;
171 
172 	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
173 	if (!tid_tx || !tid_tx->bar_pending)
174 		return;
175 
176 	tid_tx->bar_pending = false;
177 	ieee80211_send_bar(&sta->sdata->vif, addr, tid, tid_tx->failed_bar_ssn);
178 }
179 
180 static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
181 {
182 	struct ieee80211_mgmt *mgmt = (void *) skb->data;
183 	struct ieee80211_local *local = sta->local;
184 	struct ieee80211_sub_if_data *sdata = sta->sdata;
185 
186 	if (ieee80211_is_data_qos(mgmt->frame_control)) {
187 		struct ieee80211_hdr *hdr = (void *) skb->data;
188 		u8 *qc = ieee80211_get_qos_ctl(hdr);
189 		u16 tid = qc[0] & 0xf;
190 
191 		ieee80211_check_pending_bar(sta, hdr->addr1, tid);
192 	}
193 
194 	if (ieee80211_is_action(mgmt->frame_control) &&
195 	    sdata->vif.type == NL80211_IFTYPE_STATION &&
196 	    mgmt->u.action.category == WLAN_CATEGORY_HT &&
197 	    mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS) {
198 		/*
199 		 * This update looks racy, but isn't -- if we come
200 		 * here we've definitely got a station that we're
201 		 * talking to, and on a managed interface that can
202 		 * only be the AP. And the only other place updating
203 		 * this variable is before we're associated.
204 		 */
205 		switch (mgmt->u.action.u.ht_smps.smps_control) {
206 		case WLAN_HT_SMPS_CONTROL_DYNAMIC:
207 			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_DYNAMIC;
208 			break;
209 		case WLAN_HT_SMPS_CONTROL_STATIC:
210 			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_STATIC;
211 			break;
212 		case WLAN_HT_SMPS_CONTROL_DISABLED:
213 		default: /* shouldn't happen since we don't send that */
214 			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_OFF;
215 			break;
216 		}
217 
218 		ieee80211_queue_work(&local->hw, &local->recalc_smps);
219 	}
220 }
221 
222 static void ieee80211_set_bar_pending(struct sta_info *sta, u8 tid, u16 ssn)
223 {
224 	struct tid_ampdu_tx *tid_tx;
225 
226 	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
227 	if (!tid_tx)
228 		return;
229 
230 	tid_tx->failed_bar_ssn = ssn;
231 	tid_tx->bar_pending = true;
232 }
233 
234 static int ieee80211_tx_radiotap_len(struct ieee80211_tx_info *info)
235 {
236 	int len = sizeof(struct ieee80211_radiotap_header);
237 
238 	/* IEEE80211_RADIOTAP_RATE rate */
239 	if (info->status.rates[0].idx >= 0 &&
240 	    !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
241 		len += 2;
242 
243 	/* IEEE80211_RADIOTAP_TX_FLAGS */
244 	len += 2;
245 
246 	/* IEEE80211_RADIOTAP_DATA_RETRIES */
247 	len += 1;
248 
249 	/* IEEE80211_TX_RC_MCS */
250 	if (info->status.rates[0].idx >= 0 &&
251 	    info->status.rates[0].flags & IEEE80211_TX_RC_MCS)
252 		len += 3;
253 
254 	return len;
255 }
256 
257 static void ieee80211_add_tx_radiotap_header(struct ieee80211_supported_band
258 					     *sband, struct sk_buff *skb,
259 					     int retry_count, int rtap_len)
260 {
261 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
262 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
263 	struct ieee80211_radiotap_header *rthdr;
264 	unsigned char *pos;
265 	u16 txflags;
266 
267 	rthdr = (struct ieee80211_radiotap_header *) skb_push(skb, rtap_len);
268 
269 	memset(rthdr, 0, rtap_len);
270 	rthdr->it_len = cpu_to_le16(rtap_len);
271 	rthdr->it_present =
272 		cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
273 			    (1 << IEEE80211_RADIOTAP_DATA_RETRIES));
274 	pos = (unsigned char *)(rthdr + 1);
275 
276 	/*
277 	 * XXX: Once radiotap gets the bitmap reset thing the vendor
278 	 *	extensions proposal contains, we can actually report
279 	 *	the whole set of tries we did.
280 	 */
281 
282 	/* IEEE80211_RADIOTAP_RATE */
283 	if (info->status.rates[0].idx >= 0 &&
284 	    !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS)) {
285 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
286 		*pos = sband->bitrates[info->status.rates[0].idx].bitrate / 5;
287 		/* padding for tx flags */
288 		pos += 2;
289 	}
290 
291 	/* IEEE80211_RADIOTAP_TX_FLAGS */
292 	txflags = 0;
293 	if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
294 	    !is_multicast_ether_addr(hdr->addr1))
295 		txflags |= IEEE80211_RADIOTAP_F_TX_FAIL;
296 
297 	if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
298 	    (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
299 		txflags |= IEEE80211_RADIOTAP_F_TX_CTS;
300 	else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
301 		txflags |= IEEE80211_RADIOTAP_F_TX_RTS;
302 
303 	put_unaligned_le16(txflags, pos);
304 	pos += 2;
305 
306 	/* IEEE80211_RADIOTAP_DATA_RETRIES */
307 	/* for now report the total retry_count */
308 	*pos = retry_count;
309 	pos++;
310 
311 	/* IEEE80211_TX_RC_MCS */
312 	if (info->status.rates[0].idx >= 0 &&
313 	    info->status.rates[0].flags & IEEE80211_TX_RC_MCS) {
314 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
315 		pos[0] = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
316 			 IEEE80211_RADIOTAP_MCS_HAVE_GI |
317 			 IEEE80211_RADIOTAP_MCS_HAVE_BW;
318 		if (info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
319 			pos[1] |= IEEE80211_RADIOTAP_MCS_SGI;
320 		if (info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
321 			pos[1] |= IEEE80211_RADIOTAP_MCS_BW_40;
322 		if (info->status.rates[0].flags & IEEE80211_TX_RC_GREEN_FIELD)
323 			pos[1] |= IEEE80211_RADIOTAP_MCS_FMT_GF;
324 		pos[2] = info->status.rates[0].idx;
325 		pos += 3;
326 	}
327 
328 }
329 
330 /*
331  * Use a static threshold for now, best value to be determined
332  * by testing ...
333  * Should it depend on:
334  *  - on # of retransmissions
335  *  - current throughput (higher value for higher tpt)?
336  */
337 #define STA_LOST_PKT_THRESHOLD	50
338 
339 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
340 {
341 	struct sk_buff *skb2;
342 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
343 	struct ieee80211_local *local = hw_to_local(hw);
344 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
345 	__le16 fc;
346 	struct ieee80211_supported_band *sband;
347 	struct ieee80211_sub_if_data *sdata;
348 	struct net_device *prev_dev = NULL;
349 	struct sta_info *sta, *tmp;
350 	int retry_count = -1, i;
351 	int rates_idx = -1;
352 	bool send_to_cooked;
353 	bool acked;
354 	struct ieee80211_bar *bar;
355 	int rtap_len;
356 
357 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
358 		if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
359 		    !(info->flags & IEEE80211_TX_STAT_AMPDU)) {
360 			/* just the first aggr frame carry status info */
361 			info->status.rates[i].idx = -1;
362 			info->status.rates[i].count = 0;
363 			break;
364 		} else if (info->status.rates[i].idx < 0) {
365 			break;
366 		} else if (i >= hw->max_report_rates) {
367 			/* the HW cannot have attempted that rate */
368 			info->status.rates[i].idx = -1;
369 			info->status.rates[i].count = 0;
370 			break;
371 		}
372 
373 		retry_count += info->status.rates[i].count;
374 	}
375 	rates_idx = i - 1;
376 
377 	if (retry_count < 0)
378 		retry_count = 0;
379 
380 	rcu_read_lock();
381 
382 	sband = local->hw.wiphy->bands[info->band];
383 	fc = hdr->frame_control;
384 
385 	for_each_sta_info(local, hdr->addr1, sta, tmp) {
386 		/* skip wrong virtual interface */
387 		if (!ether_addr_equal(hdr->addr2, sta->sdata->vif.addr))
388 			continue;
389 
390 		if (info->flags & IEEE80211_TX_STATUS_EOSP)
391 			clear_sta_flag(sta, WLAN_STA_SP);
392 
393 		acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
394 		if (!acked && test_sta_flag(sta, WLAN_STA_PS_STA)) {
395 			/*
396 			 * The STA is in power save mode, so assume
397 			 * that this TX packet failed because of that.
398 			 */
399 			ieee80211_handle_filtered_frame(local, sta, skb);
400 			rcu_read_unlock();
401 			return;
402 		}
403 
404 		if ((local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) &&
405 		    (rates_idx != -1))
406 			sta->last_tx_rate = info->status.rates[rates_idx];
407 
408 		if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
409 		    (ieee80211_is_data_qos(fc))) {
410 			u16 tid, ssn;
411 			u8 *qc;
412 
413 			qc = ieee80211_get_qos_ctl(hdr);
414 			tid = qc[0] & 0xf;
415 			ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
416 						& IEEE80211_SCTL_SEQ);
417 			ieee80211_send_bar(&sta->sdata->vif, hdr->addr1,
418 					   tid, ssn);
419 		}
420 
421 		if (!acked && ieee80211_is_back_req(fc)) {
422 			u16 tid, control;
423 
424 			/*
425 			 * BAR failed, store the last SSN and retry sending
426 			 * the BAR when the next unicast transmission on the
427 			 * same TID succeeds.
428 			 */
429 			bar = (struct ieee80211_bar *) skb->data;
430 			control = le16_to_cpu(bar->control);
431 			if (!(control & IEEE80211_BAR_CTRL_MULTI_TID)) {
432 				u16 ssn = le16_to_cpu(bar->start_seq_num);
433 
434 				tid = (control &
435 				       IEEE80211_BAR_CTRL_TID_INFO_MASK) >>
436 				      IEEE80211_BAR_CTRL_TID_INFO_SHIFT;
437 
438 				ieee80211_set_bar_pending(sta, tid, ssn);
439 			}
440 		}
441 
442 		if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
443 			ieee80211_handle_filtered_frame(local, sta, skb);
444 			rcu_read_unlock();
445 			return;
446 		} else {
447 			if (!acked)
448 				sta->tx_retry_failed++;
449 			sta->tx_retry_count += retry_count;
450 		}
451 
452 		rate_control_tx_status(local, sband, sta, skb);
453 		if (ieee80211_vif_is_mesh(&sta->sdata->vif))
454 			ieee80211s_update_metric(local, sta, skb);
455 
456 		if (!(info->flags & IEEE80211_TX_CTL_INJECTED) && acked)
457 			ieee80211_frame_acked(sta, skb);
458 
459 		if ((sta->sdata->vif.type == NL80211_IFTYPE_STATION) &&
460 		    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS))
461 			ieee80211_sta_tx_notify(sta->sdata, (void *) skb->data, acked);
462 
463 		if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) {
464 			if (info->flags & IEEE80211_TX_STAT_ACK) {
465 				if (sta->lost_packets)
466 					sta->lost_packets = 0;
467 			} else if (++sta->lost_packets >= STA_LOST_PKT_THRESHOLD) {
468 				cfg80211_cqm_pktloss_notify(sta->sdata->dev,
469 							    sta->sta.addr,
470 							    sta->lost_packets,
471 							    GFP_ATOMIC);
472 				sta->lost_packets = 0;
473 			}
474 		}
475 	}
476 
477 	rcu_read_unlock();
478 
479 	ieee80211_led_tx(local, 0);
480 
481 	/* SNMP counters
482 	 * Fragments are passed to low-level drivers as separate skbs, so these
483 	 * are actually fragments, not frames. Update frame counters only for
484 	 * the first fragment of the frame. */
485 	if (info->flags & IEEE80211_TX_STAT_ACK) {
486 		if (ieee80211_is_first_frag(hdr->seq_ctrl)) {
487 			local->dot11TransmittedFrameCount++;
488 			if (is_multicast_ether_addr(hdr->addr1))
489 				local->dot11MulticastTransmittedFrameCount++;
490 			if (retry_count > 0)
491 				local->dot11RetryCount++;
492 			if (retry_count > 1)
493 				local->dot11MultipleRetryCount++;
494 		}
495 
496 		/* This counter shall be incremented for an acknowledged MPDU
497 		 * with an individual address in the address 1 field or an MPDU
498 		 * with a multicast address in the address 1 field of type Data
499 		 * or Management. */
500 		if (!is_multicast_ether_addr(hdr->addr1) ||
501 		    ieee80211_is_data(fc) ||
502 		    ieee80211_is_mgmt(fc))
503 			local->dot11TransmittedFragmentCount++;
504 	} else {
505 		if (ieee80211_is_first_frag(hdr->seq_ctrl))
506 			local->dot11FailedCount++;
507 	}
508 
509 	if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
510 	    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) &&
511 	    !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
512 	    local->ps_sdata && !(local->scanning)) {
513 		if (info->flags & IEEE80211_TX_STAT_ACK) {
514 			local->ps_sdata->u.mgd.flags |=
515 					IEEE80211_STA_NULLFUNC_ACKED;
516 		} else
517 			mod_timer(&local->dynamic_ps_timer, jiffies +
518 					msecs_to_jiffies(10));
519 	}
520 
521 	if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
522 		u64 cookie = (unsigned long)skb;
523 
524 		if (ieee80211_is_nullfunc(hdr->frame_control) ||
525 		    ieee80211_is_qos_nullfunc(hdr->frame_control)) {
526 			acked = info->flags & IEEE80211_TX_STAT_ACK;
527 
528 			cfg80211_probe_status(skb->dev, hdr->addr1,
529 					      cookie, acked, GFP_ATOMIC);
530 		} else {
531 			struct ieee80211_work *wk;
532 
533 			rcu_read_lock();
534 			list_for_each_entry_rcu(wk, &local->work_list, list) {
535 				if (wk->type != IEEE80211_WORK_OFFCHANNEL_TX)
536 					continue;
537 				if (wk->offchan_tx.frame != skb)
538 					continue;
539 				wk->offchan_tx.status = true;
540 				break;
541 			}
542 			rcu_read_unlock();
543 			if (local->hw_roc_skb_for_status == skb) {
544 				cookie = local->hw_roc_cookie ^ 2;
545 				local->hw_roc_skb_for_status = NULL;
546 			}
547 
548 			cfg80211_mgmt_tx_status(
549 				skb->dev, cookie, skb->data, skb->len,
550 				!!(info->flags & IEEE80211_TX_STAT_ACK),
551 				GFP_ATOMIC);
552 		}
553 	}
554 
555 	if (unlikely(info->ack_frame_id)) {
556 		struct sk_buff *ack_skb;
557 		unsigned long flags;
558 
559 		spin_lock_irqsave(&local->ack_status_lock, flags);
560 		ack_skb = idr_find(&local->ack_status_frames,
561 				   info->ack_frame_id);
562 		if (ack_skb)
563 			idr_remove(&local->ack_status_frames,
564 				   info->ack_frame_id);
565 		spin_unlock_irqrestore(&local->ack_status_lock, flags);
566 
567 		/* consumes ack_skb */
568 		if (ack_skb)
569 			skb_complete_wifi_ack(ack_skb,
570 				info->flags & IEEE80211_TX_STAT_ACK);
571 	}
572 
573 	/* this was a transmitted frame, but now we want to reuse it */
574 	skb_orphan(skb);
575 
576 	/* Need to make a copy before skb->cb gets cleared */
577 	send_to_cooked = !!(info->flags & IEEE80211_TX_CTL_INJECTED) ||
578 			 !(ieee80211_is_data(fc));
579 
580 	/*
581 	 * This is a bit racy but we can avoid a lot of work
582 	 * with this test...
583 	 */
584 	if (!local->monitors && (!send_to_cooked || !local->cooked_mntrs)) {
585 		dev_kfree_skb(skb);
586 		return;
587 	}
588 
589 	/* send frame to monitor interfaces now */
590 	rtap_len = ieee80211_tx_radiotap_len(info);
591 	if (WARN_ON_ONCE(skb_headroom(skb) < rtap_len)) {
592 		printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
593 		dev_kfree_skb(skb);
594 		return;
595 	}
596 	ieee80211_add_tx_radiotap_header(sband, skb, retry_count, rtap_len);
597 
598 	/* XXX: is this sufficient for BPF? */
599 	skb_set_mac_header(skb, 0);
600 	skb->ip_summed = CHECKSUM_UNNECESSARY;
601 	skb->pkt_type = PACKET_OTHERHOST;
602 	skb->protocol = htons(ETH_P_802_2);
603 	memset(skb->cb, 0, sizeof(skb->cb));
604 
605 	rcu_read_lock();
606 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
607 		if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
608 			if (!ieee80211_sdata_running(sdata))
609 				continue;
610 
611 			if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
612 			    !send_to_cooked)
613 				continue;
614 
615 			if (prev_dev) {
616 				skb2 = skb_clone(skb, GFP_ATOMIC);
617 				if (skb2) {
618 					skb2->dev = prev_dev;
619 					netif_rx(skb2);
620 				}
621 			}
622 
623 			prev_dev = sdata->dev;
624 		}
625 	}
626 	if (prev_dev) {
627 		skb->dev = prev_dev;
628 		netif_rx(skb);
629 		skb = NULL;
630 	}
631 	rcu_read_unlock();
632 	dev_kfree_skb(skb);
633 }
634 EXPORT_SYMBOL(ieee80211_tx_status);
635 
636 void ieee80211_report_low_ack(struct ieee80211_sta *pubsta, u32 num_packets)
637 {
638 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
639 	cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
640 				    num_packets, GFP_ATOMIC);
641 }
642 EXPORT_SYMBOL(ieee80211_report_low_ack);
643 
644 void ieee80211_free_txskb(struct ieee80211_hw *hw, struct sk_buff *skb)
645 {
646 	struct ieee80211_local *local = hw_to_local(hw);
647 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
648 
649 	if (unlikely(info->ack_frame_id)) {
650 		struct sk_buff *ack_skb;
651 		unsigned long flags;
652 
653 		spin_lock_irqsave(&local->ack_status_lock, flags);
654 		ack_skb = idr_find(&local->ack_status_frames,
655 				   info->ack_frame_id);
656 		if (ack_skb)
657 			idr_remove(&local->ack_status_frames,
658 				   info->ack_frame_id);
659 		spin_unlock_irqrestore(&local->ack_status_lock, flags);
660 
661 		/* consumes ack_skb */
662 		if (ack_skb)
663 			dev_kfree_skb_any(ack_skb);
664 	}
665 
666 	dev_kfree_skb_any(skb);
667 }
668 EXPORT_SYMBOL(ieee80211_free_txskb);
669