xref: /openbmc/linux/net/mac80211/status.c (revision 1eb4c977)
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->status.rates[i].idx < 0) {
359 			break;
360 		} else if (i >= hw->max_report_rates) {
361 			/* the HW cannot have attempted that rate */
362 			info->status.rates[i].idx = -1;
363 			info->status.rates[i].count = 0;
364 			break;
365 		}
366 
367 		retry_count += info->status.rates[i].count;
368 	}
369 	rates_idx = i - 1;
370 
371 	if (retry_count < 0)
372 		retry_count = 0;
373 
374 	rcu_read_lock();
375 
376 	sband = local->hw.wiphy->bands[info->band];
377 	fc = hdr->frame_control;
378 
379 	for_each_sta_info(local, hdr->addr1, sta, tmp) {
380 		/* skip wrong virtual interface */
381 		if (compare_ether_addr(hdr->addr2, sta->sdata->vif.addr))
382 			continue;
383 
384 		if (info->flags & IEEE80211_TX_STATUS_EOSP)
385 			clear_sta_flag(sta, WLAN_STA_SP);
386 
387 		acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
388 		if (!acked && test_sta_flag(sta, WLAN_STA_PS_STA)) {
389 			/*
390 			 * The STA is in power save mode, so assume
391 			 * that this TX packet failed because of that.
392 			 */
393 			ieee80211_handle_filtered_frame(local, sta, skb);
394 			rcu_read_unlock();
395 			return;
396 		}
397 
398 		if ((local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) &&
399 		    (rates_idx != -1))
400 			sta->last_tx_rate = info->status.rates[rates_idx];
401 
402 		if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
403 		    (ieee80211_is_data_qos(fc))) {
404 			u16 tid, ssn;
405 			u8 *qc;
406 
407 			qc = ieee80211_get_qos_ctl(hdr);
408 			tid = qc[0] & 0xf;
409 			ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
410 						& IEEE80211_SCTL_SEQ);
411 			ieee80211_send_bar(&sta->sdata->vif, hdr->addr1,
412 					   tid, ssn);
413 		}
414 
415 		if (!acked && ieee80211_is_back_req(fc)) {
416 			u16 tid, control;
417 
418 			/*
419 			 * BAR failed, store the last SSN and retry sending
420 			 * the BAR when the next unicast transmission on the
421 			 * same TID succeeds.
422 			 */
423 			bar = (struct ieee80211_bar *) skb->data;
424 			control = le16_to_cpu(bar->control);
425 			if (!(control & IEEE80211_BAR_CTRL_MULTI_TID)) {
426 				u16 ssn = le16_to_cpu(bar->start_seq_num);
427 
428 				tid = (control &
429 				       IEEE80211_BAR_CTRL_TID_INFO_MASK) >>
430 				      IEEE80211_BAR_CTRL_TID_INFO_SHIFT;
431 
432 				ieee80211_set_bar_pending(sta, tid, ssn);
433 			}
434 		}
435 
436 		if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
437 			ieee80211_handle_filtered_frame(local, sta, skb);
438 			rcu_read_unlock();
439 			return;
440 		} else {
441 			if (!acked)
442 				sta->tx_retry_failed++;
443 			sta->tx_retry_count += retry_count;
444 		}
445 
446 		rate_control_tx_status(local, sband, sta, skb);
447 		if (ieee80211_vif_is_mesh(&sta->sdata->vif))
448 			ieee80211s_update_metric(local, sta, skb);
449 
450 		if (!(info->flags & IEEE80211_TX_CTL_INJECTED) && acked)
451 			ieee80211_frame_acked(sta, skb);
452 
453 		if ((sta->sdata->vif.type == NL80211_IFTYPE_STATION) &&
454 		    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS))
455 			ieee80211_sta_tx_notify(sta->sdata, (void *) skb->data, acked);
456 
457 		if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) {
458 			if (info->flags & IEEE80211_TX_STAT_ACK) {
459 				if (sta->lost_packets)
460 					sta->lost_packets = 0;
461 			} else if (++sta->lost_packets >= STA_LOST_PKT_THRESHOLD) {
462 				cfg80211_cqm_pktloss_notify(sta->sdata->dev,
463 							    sta->sta.addr,
464 							    sta->lost_packets,
465 							    GFP_ATOMIC);
466 				sta->lost_packets = 0;
467 			}
468 		}
469 	}
470 
471 	rcu_read_unlock();
472 
473 	ieee80211_led_tx(local, 0);
474 
475 	/* SNMP counters
476 	 * Fragments are passed to low-level drivers as separate skbs, so these
477 	 * are actually fragments, not frames. Update frame counters only for
478 	 * the first fragment of the frame. */
479 	if (info->flags & IEEE80211_TX_STAT_ACK) {
480 		if (ieee80211_is_first_frag(hdr->seq_ctrl)) {
481 			local->dot11TransmittedFrameCount++;
482 			if (is_multicast_ether_addr(hdr->addr1))
483 				local->dot11MulticastTransmittedFrameCount++;
484 			if (retry_count > 0)
485 				local->dot11RetryCount++;
486 			if (retry_count > 1)
487 				local->dot11MultipleRetryCount++;
488 		}
489 
490 		/* This counter shall be incremented for an acknowledged MPDU
491 		 * with an individual address in the address 1 field or an MPDU
492 		 * with a multicast address in the address 1 field of type Data
493 		 * or Management. */
494 		if (!is_multicast_ether_addr(hdr->addr1) ||
495 		    ieee80211_is_data(fc) ||
496 		    ieee80211_is_mgmt(fc))
497 			local->dot11TransmittedFragmentCount++;
498 	} else {
499 		if (ieee80211_is_first_frag(hdr->seq_ctrl))
500 			local->dot11FailedCount++;
501 	}
502 
503 	if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
504 	    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) &&
505 	    !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
506 	    local->ps_sdata && !(local->scanning)) {
507 		if (info->flags & IEEE80211_TX_STAT_ACK) {
508 			local->ps_sdata->u.mgd.flags |=
509 					IEEE80211_STA_NULLFUNC_ACKED;
510 		} else
511 			mod_timer(&local->dynamic_ps_timer, jiffies +
512 					msecs_to_jiffies(10));
513 	}
514 
515 	if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
516 		u64 cookie = (unsigned long)skb;
517 
518 		if (ieee80211_is_nullfunc(hdr->frame_control) ||
519 		    ieee80211_is_qos_nullfunc(hdr->frame_control)) {
520 			acked = info->flags & IEEE80211_TX_STAT_ACK;
521 
522 			cfg80211_probe_status(skb->dev, hdr->addr1,
523 					      cookie, acked, GFP_ATOMIC);
524 		} else {
525 			struct ieee80211_work *wk;
526 
527 			rcu_read_lock();
528 			list_for_each_entry_rcu(wk, &local->work_list, list) {
529 				if (wk->type != IEEE80211_WORK_OFFCHANNEL_TX)
530 					continue;
531 				if (wk->offchan_tx.frame != skb)
532 					continue;
533 				wk->offchan_tx.status = true;
534 				break;
535 			}
536 			rcu_read_unlock();
537 			if (local->hw_roc_skb_for_status == skb) {
538 				cookie = local->hw_roc_cookie ^ 2;
539 				local->hw_roc_skb_for_status = NULL;
540 			}
541 
542 			cfg80211_mgmt_tx_status(
543 				skb->dev, cookie, skb->data, skb->len,
544 				!!(info->flags & IEEE80211_TX_STAT_ACK),
545 				GFP_ATOMIC);
546 		}
547 	}
548 
549 	if (unlikely(info->ack_frame_id)) {
550 		struct sk_buff *ack_skb;
551 		unsigned long flags;
552 
553 		spin_lock_irqsave(&local->ack_status_lock, flags);
554 		ack_skb = idr_find(&local->ack_status_frames,
555 				   info->ack_frame_id);
556 		if (ack_skb)
557 			idr_remove(&local->ack_status_frames,
558 				   info->ack_frame_id);
559 		spin_unlock_irqrestore(&local->ack_status_lock, flags);
560 
561 		/* consumes ack_skb */
562 		if (ack_skb)
563 			skb_complete_wifi_ack(ack_skb,
564 				info->flags & IEEE80211_TX_STAT_ACK);
565 	}
566 
567 	/* this was a transmitted frame, but now we want to reuse it */
568 	skb_orphan(skb);
569 
570 	/* Need to make a copy before skb->cb gets cleared */
571 	send_to_cooked = !!(info->flags & IEEE80211_TX_CTL_INJECTED) ||
572 			 !(ieee80211_is_data(fc));
573 
574 	/*
575 	 * This is a bit racy but we can avoid a lot of work
576 	 * with this test...
577 	 */
578 	if (!local->monitors && (!send_to_cooked || !local->cooked_mntrs)) {
579 		dev_kfree_skb(skb);
580 		return;
581 	}
582 
583 	/* send frame to monitor interfaces now */
584 	rtap_len = ieee80211_tx_radiotap_len(info);
585 	if (WARN_ON_ONCE(skb_headroom(skb) < rtap_len)) {
586 		printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
587 		dev_kfree_skb(skb);
588 		return;
589 	}
590 	ieee80211_add_tx_radiotap_header(sband, skb, retry_count, rtap_len);
591 
592 	/* XXX: is this sufficient for BPF? */
593 	skb_set_mac_header(skb, 0);
594 	skb->ip_summed = CHECKSUM_UNNECESSARY;
595 	skb->pkt_type = PACKET_OTHERHOST;
596 	skb->protocol = htons(ETH_P_802_2);
597 	memset(skb->cb, 0, sizeof(skb->cb));
598 
599 	rcu_read_lock();
600 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
601 		if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
602 			if (!ieee80211_sdata_running(sdata))
603 				continue;
604 
605 			if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
606 			    !send_to_cooked)
607 				continue;
608 
609 			if (prev_dev) {
610 				skb2 = skb_clone(skb, GFP_ATOMIC);
611 				if (skb2) {
612 					skb2->dev = prev_dev;
613 					netif_rx(skb2);
614 				}
615 			}
616 
617 			prev_dev = sdata->dev;
618 		}
619 	}
620 	if (prev_dev) {
621 		skb->dev = prev_dev;
622 		netif_rx(skb);
623 		skb = NULL;
624 	}
625 	rcu_read_unlock();
626 	dev_kfree_skb(skb);
627 }
628 EXPORT_SYMBOL(ieee80211_tx_status);
629 
630 void ieee80211_report_low_ack(struct ieee80211_sta *pubsta, u32 num_packets)
631 {
632 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
633 	cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
634 				    num_packets, GFP_ATOMIC);
635 }
636 EXPORT_SYMBOL(ieee80211_report_low_ack);
637 
638 void ieee80211_free_txskb(struct ieee80211_hw *hw, struct sk_buff *skb)
639 {
640 	struct ieee80211_local *local = hw_to_local(hw);
641 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
642 
643 	if (unlikely(info->ack_frame_id)) {
644 		struct sk_buff *ack_skb;
645 		unsigned long flags;
646 
647 		spin_lock_irqsave(&local->ack_status_lock, flags);
648 		ack_skb = idr_find(&local->ack_status_frames,
649 				   info->ack_frame_id);
650 		if (ack_skb)
651 			idr_remove(&local->ack_status_frames,
652 				   info->ack_frame_id);
653 		spin_unlock_irqrestore(&local->ack_status_lock, flags);
654 
655 		/* consumes ack_skb */
656 		if (ack_skb)
657 			dev_kfree_skb_any(ack_skb);
658 	}
659 
660 	dev_kfree_skb_any(skb);
661 }
662 EXPORT_SYMBOL(ieee80211_free_txskb);
663