xref: /linux/net/mac80211/status.c (revision a67ff6a54095e27093ea501fb143fefe51a536c2)
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 <net/mac80211.h>
14 #include "ieee80211_i.h"
15 #include "rate.h"
16 #include "mesh.h"
17 #include "led.h"
18 #include "wme.h"
19 
20 
21 void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
22 				 struct sk_buff *skb)
23 {
24 	struct ieee80211_local *local = hw_to_local(hw);
25 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
26 	int tmp;
27 
28 	skb->pkt_type = IEEE80211_TX_STATUS_MSG;
29 	skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
30 		       &local->skb_queue : &local->skb_queue_unreliable, skb);
31 	tmp = skb_queue_len(&local->skb_queue) +
32 		skb_queue_len(&local->skb_queue_unreliable);
33 	while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
34 	       (skb = skb_dequeue(&local->skb_queue_unreliable))) {
35 		dev_kfree_skb_irq(skb);
36 		tmp--;
37 		I802_DEBUG_INC(local->tx_status_drop);
38 	}
39 	tasklet_schedule(&local->tasklet);
40 }
41 EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);
42 
43 static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
44 					    struct sta_info *sta,
45 					    struct sk_buff *skb)
46 {
47 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
48 	struct ieee80211_hdr *hdr = (void *)skb->data;
49 	int ac;
50 
51 	/*
52 	 * This skb 'survived' a round-trip through the driver, and
53 	 * hopefully the driver didn't mangle it too badly. However,
54 	 * we can definitely not rely on the control information
55 	 * being correct. Clear it so we don't get junk there, and
56 	 * indicate that it needs new processing, but must not be
57 	 * modified/encrypted again.
58 	 */
59 	memset(&info->control, 0, sizeof(info->control));
60 
61 	info->control.jiffies = jiffies;
62 	info->control.vif = &sta->sdata->vif;
63 	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING |
64 		       IEEE80211_TX_INTFL_RETRANSMISSION;
65 	info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;
66 
67 	sta->tx_filtered_count++;
68 
69 	/*
70 	 * Clear more-data bit on filtered frames, it might be set
71 	 * but later frames might time out so it might have to be
72 	 * clear again ... It's all rather unlikely (this frame
73 	 * should time out first, right?) but let's not confuse
74 	 * peers unnecessarily.
75 	 */
76 	if (hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_MOREDATA))
77 		hdr->frame_control &= ~cpu_to_le16(IEEE80211_FCTL_MOREDATA);
78 
79 	if (ieee80211_is_data_qos(hdr->frame_control)) {
80 		u8 *p = ieee80211_get_qos_ctl(hdr);
81 		int tid = *p & IEEE80211_QOS_CTL_TID_MASK;
82 
83 		/*
84 		 * Clear EOSP if set, this could happen e.g.
85 		 * if an absence period (us being a P2P GO)
86 		 * shortens the SP.
87 		 */
88 		if (*p & IEEE80211_QOS_CTL_EOSP)
89 			*p &= ~IEEE80211_QOS_CTL_EOSP;
90 		ac = ieee802_1d_to_ac[tid & 7];
91 	} else {
92 		ac = IEEE80211_AC_BE;
93 	}
94 
95 	/*
96 	 * Clear the TX filter mask for this STA when sending the next
97 	 * packet. If the STA went to power save mode, this will happen
98 	 * when it wakes up for the next time.
99 	 */
100 	set_sta_flag(sta, WLAN_STA_CLEAR_PS_FILT);
101 
102 	/*
103 	 * This code races in the following way:
104 	 *
105 	 *  (1) STA sends frame indicating it will go to sleep and does so
106 	 *  (2) hardware/firmware adds STA to filter list, passes frame up
107 	 *  (3) hardware/firmware processes TX fifo and suppresses a frame
108 	 *  (4) we get TX status before having processed the frame and
109 	 *	knowing that the STA has gone to sleep.
110 	 *
111 	 * This is actually quite unlikely even when both those events are
112 	 * processed from interrupts coming in quickly after one another or
113 	 * even at the same time because we queue both TX status events and
114 	 * RX frames to be processed by a tasklet and process them in the
115 	 * same order that they were received or TX status last. Hence, there
116 	 * is no race as long as the frame RX is processed before the next TX
117 	 * status, which drivers can ensure, see below.
118 	 *
119 	 * Note that this can only happen if the hardware or firmware can
120 	 * actually add STAs to the filter list, if this is done by the
121 	 * driver in response to set_tim() (which will only reduce the race
122 	 * this whole filtering tries to solve, not completely solve it)
123 	 * this situation cannot happen.
124 	 *
125 	 * To completely solve this race drivers need to make sure that they
126 	 *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
127 	 *	functions and
128 	 *  (b) always process RX events before TX status events if ordering
129 	 *      can be unknown, for example with different interrupt status
130 	 *	bits.
131 	 *  (c) if PS mode transitions are manual (i.e. the flag
132 	 *      %IEEE80211_HW_AP_LINK_PS is set), always process PS state
133 	 *      changes before calling TX status events if ordering can be
134 	 *	unknown.
135 	 */
136 	if (test_sta_flag(sta, WLAN_STA_PS_STA) &&
137 	    skb_queue_len(&sta->tx_filtered[ac]) < STA_MAX_TX_BUFFER) {
138 		skb_queue_tail(&sta->tx_filtered[ac], skb);
139 		sta_info_recalc_tim(sta);
140 
141 		if (!timer_pending(&local->sta_cleanup))
142 			mod_timer(&local->sta_cleanup,
143 				  round_jiffies(jiffies +
144 						STA_INFO_CLEANUP_INTERVAL));
145 		return;
146 	}
147 
148 	if (!test_sta_flag(sta, WLAN_STA_PS_STA) &&
149 	    !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
150 		/* Software retry the packet once */
151 		info->flags |= IEEE80211_TX_INTFL_RETRIED;
152 		ieee80211_add_pending_skb(local, skb);
153 		return;
154 	}
155 
156 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
157 	if (net_ratelimit())
158 		wiphy_debug(local->hw.wiphy,
159 			    "dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
160 			    skb_queue_len(&sta->tx_filtered[ac]),
161 			    !!test_sta_flag(sta, WLAN_STA_PS_STA), jiffies);
162 #endif
163 	dev_kfree_skb(skb);
164 }
165 
166 static void ieee80211_check_pending_bar(struct sta_info *sta, u8 *addr, u8 tid)
167 {
168 	struct tid_ampdu_tx *tid_tx;
169 
170 	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
171 	if (!tid_tx || !tid_tx->bar_pending)
172 		return;
173 
174 	tid_tx->bar_pending = false;
175 	ieee80211_send_bar(&sta->sdata->vif, addr, tid, tid_tx->failed_bar_ssn);
176 }
177 
178 static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
179 {
180 	struct ieee80211_mgmt *mgmt = (void *) skb->data;
181 	struct ieee80211_local *local = sta->local;
182 	struct ieee80211_sub_if_data *sdata = sta->sdata;
183 
184 	if (ieee80211_is_data_qos(mgmt->frame_control)) {
185 		struct ieee80211_hdr *hdr = (void *) skb->data;
186 		u8 *qc = ieee80211_get_qos_ctl(hdr);
187 		u16 tid = qc[0] & 0xf;
188 
189 		ieee80211_check_pending_bar(sta, hdr->addr1, tid);
190 	}
191 
192 	if (ieee80211_is_action(mgmt->frame_control) &&
193 	    sdata->vif.type == NL80211_IFTYPE_STATION &&
194 	    mgmt->u.action.category == WLAN_CATEGORY_HT &&
195 	    mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS) {
196 		/*
197 		 * This update looks racy, but isn't -- if we come
198 		 * here we've definitely got a station that we're
199 		 * talking to, and on a managed interface that can
200 		 * only be the AP. And the only other place updating
201 		 * this variable is before we're associated.
202 		 */
203 		switch (mgmt->u.action.u.ht_smps.smps_control) {
204 		case WLAN_HT_SMPS_CONTROL_DYNAMIC:
205 			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_DYNAMIC;
206 			break;
207 		case WLAN_HT_SMPS_CONTROL_STATIC:
208 			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_STATIC;
209 			break;
210 		case WLAN_HT_SMPS_CONTROL_DISABLED:
211 		default: /* shouldn't happen since we don't send that */
212 			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_OFF;
213 			break;
214 		}
215 
216 		ieee80211_queue_work(&local->hw, &local->recalc_smps);
217 	}
218 }
219 
220 static void ieee80211_set_bar_pending(struct sta_info *sta, u8 tid, u16 ssn)
221 {
222 	struct tid_ampdu_tx *tid_tx;
223 
224 	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
225 	if (!tid_tx)
226 		return;
227 
228 	tid_tx->failed_bar_ssn = ssn;
229 	tid_tx->bar_pending = true;
230 }
231 
232 static int ieee80211_tx_radiotap_len(struct ieee80211_tx_info *info)
233 {
234 	int len = sizeof(struct ieee80211_radiotap_header);
235 
236 	/* IEEE80211_RADIOTAP_RATE rate */
237 	if (info->status.rates[0].idx >= 0 &&
238 	    !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
239 		len += 2;
240 
241 	/* IEEE80211_RADIOTAP_TX_FLAGS */
242 	len += 2;
243 
244 	/* IEEE80211_RADIOTAP_DATA_RETRIES */
245 	len += 1;
246 
247 	/* IEEE80211_TX_RC_MCS */
248 	if (info->status.rates[0].idx >= 0 &&
249 	    info->status.rates[0].flags & IEEE80211_TX_RC_MCS)
250 		len += 3;
251 
252 	return len;
253 }
254 
255 static void ieee80211_add_tx_radiotap_header(struct ieee80211_supported_band
256 					     *sband, struct sk_buff *skb,
257 					     int retry_count, int rtap_len)
258 {
259 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
260 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
261 	struct ieee80211_radiotap_header *rthdr;
262 	unsigned char *pos;
263 	__le16 txflags;
264 
265 	rthdr = (struct ieee80211_radiotap_header *) skb_push(skb, rtap_len);
266 
267 	memset(rthdr, 0, rtap_len);
268 	rthdr->it_len = cpu_to_le16(rtap_len);
269 	rthdr->it_present =
270 		cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
271 			    (1 << IEEE80211_RADIOTAP_DATA_RETRIES));
272 	pos = (unsigned char *)(rthdr + 1);
273 
274 	/*
275 	 * XXX: Once radiotap gets the bitmap reset thing the vendor
276 	 *	extensions proposal contains, we can actually report
277 	 *	the whole set of tries we did.
278 	 */
279 
280 	/* IEEE80211_RADIOTAP_RATE */
281 	if (info->status.rates[0].idx >= 0 &&
282 	    !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS)) {
283 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
284 		*pos = sband->bitrates[info->status.rates[0].idx].bitrate / 5;
285 		/* padding for tx flags */
286 		pos += 2;
287 	}
288 
289 	/* IEEE80211_RADIOTAP_TX_FLAGS */
290 	txflags = 0;
291 	if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
292 	    !is_multicast_ether_addr(hdr->addr1))
293 		txflags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_FAIL);
294 
295 	if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
296 	    (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
297 		txflags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_CTS);
298 	else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
299 		txflags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_RTS);
300 
301 	put_unaligned_le16(txflags, pos);
302 	pos += 2;
303 
304 	/* IEEE80211_RADIOTAP_DATA_RETRIES */
305 	/* for now report the total retry_count */
306 	*pos = retry_count;
307 	pos++;
308 
309 	/* IEEE80211_TX_RC_MCS */
310 	if (info->status.rates[0].idx >= 0 &&
311 	    info->status.rates[0].flags & IEEE80211_TX_RC_MCS) {
312 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
313 		pos[0] = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
314 			 IEEE80211_RADIOTAP_MCS_HAVE_GI |
315 			 IEEE80211_RADIOTAP_MCS_HAVE_BW;
316 		if (info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
317 			pos[1] |= IEEE80211_RADIOTAP_MCS_SGI;
318 		if (info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
319 			pos[1] |= IEEE80211_RADIOTAP_MCS_BW_40;
320 		if (info->status.rates[0].flags & IEEE80211_TX_RC_GREEN_FIELD)
321 			pos[1] |= IEEE80211_RADIOTAP_MCS_FMT_GF;
322 		pos[2] = info->status.rates[0].idx;
323 		pos += 3;
324 	}
325 
326 }
327 
328 /*
329  * Use a static threshold for now, best value to be determined
330  * by testing ...
331  * Should it depend on:
332  *  - on # of retransmissions
333  *  - current throughput (higher value for higher tpt)?
334  */
335 #define STA_LOST_PKT_THRESHOLD	50
336 
337 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
338 {
339 	struct sk_buff *skb2;
340 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
341 	struct ieee80211_local *local = hw_to_local(hw);
342 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
343 	u16 frag, type;
344 	__le16 fc;
345 	struct ieee80211_supported_band *sband;
346 	struct ieee80211_sub_if_data *sdata;
347 	struct net_device *prev_dev = NULL;
348 	struct sta_info *sta, *tmp;
349 	int retry_count = -1, i;
350 	int rates_idx = -1;
351 	bool send_to_cooked;
352 	bool acked;
353 	struct ieee80211_bar *bar;
354 	u16 tid;
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 (memcmp(hdr->addr2, sta->sdata->vif.addr, ETH_ALEN))
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 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 
480 	frag = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG;
481 	type = le16_to_cpu(hdr->frame_control) & IEEE80211_FCTL_FTYPE;
482 
483 	if (info->flags & IEEE80211_TX_STAT_ACK) {
484 		if (frag == 0) {
485 			local->dot11TransmittedFrameCount++;
486 			if (is_multicast_ether_addr(hdr->addr1))
487 				local->dot11MulticastTransmittedFrameCount++;
488 			if (retry_count > 0)
489 				local->dot11RetryCount++;
490 			if (retry_count > 1)
491 				local->dot11MultipleRetryCount++;
492 		}
493 
494 		/* This counter shall be incremented for an acknowledged MPDU
495 		 * with an individual address in the address 1 field or an MPDU
496 		 * with a multicast address in the address 1 field of type Data
497 		 * or Management. */
498 		if (!is_multicast_ether_addr(hdr->addr1) ||
499 		    type == IEEE80211_FTYPE_DATA ||
500 		    type == IEEE80211_FTYPE_MGMT)
501 			local->dot11TransmittedFragmentCount++;
502 	} else {
503 		if (frag == 0)
504 			local->dot11FailedCount++;
505 	}
506 
507 	if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
508 	    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) &&
509 	    !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
510 	    local->ps_sdata && !(local->scanning)) {
511 		if (info->flags & IEEE80211_TX_STAT_ACK) {
512 			local->ps_sdata->u.mgd.flags |=
513 					IEEE80211_STA_NULLFUNC_ACKED;
514 		} else
515 			mod_timer(&local->dynamic_ps_timer, jiffies +
516 					msecs_to_jiffies(10));
517 	}
518 
519 	if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
520 		struct ieee80211_work *wk;
521 		u64 cookie = (unsigned long)skb;
522 
523 		rcu_read_lock();
524 		list_for_each_entry_rcu(wk, &local->work_list, list) {
525 			if (wk->type != IEEE80211_WORK_OFFCHANNEL_TX)
526 				continue;
527 			if (wk->offchan_tx.frame != skb)
528 				continue;
529 			wk->offchan_tx.status = true;
530 			break;
531 		}
532 		rcu_read_unlock();
533 		if (local->hw_roc_skb_for_status == skb) {
534 			cookie = local->hw_roc_cookie ^ 2;
535 			local->hw_roc_skb_for_status = NULL;
536 		}
537 
538 		cfg80211_mgmt_tx_status(
539 			skb->dev, cookie, skb->data, skb->len,
540 			!!(info->flags & IEEE80211_TX_STAT_ACK), GFP_ATOMIC);
541 	}
542 
543 	/* this was a transmitted frame, but now we want to reuse it */
544 	skb_orphan(skb);
545 
546 	/* Need to make a copy before skb->cb gets cleared */
547 	send_to_cooked = !!(info->flags & IEEE80211_TX_CTL_INJECTED) ||
548 			(type != IEEE80211_FTYPE_DATA);
549 
550 	/*
551 	 * This is a bit racy but we can avoid a lot of work
552 	 * with this test...
553 	 */
554 	if (!local->monitors && (!send_to_cooked || !local->cooked_mntrs)) {
555 		dev_kfree_skb(skb);
556 		return;
557 	}
558 
559 	/* send frame to monitor interfaces now */
560 	rtap_len = ieee80211_tx_radiotap_len(info);
561 	if (WARN_ON_ONCE(skb_headroom(skb) < rtap_len)) {
562 		printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
563 		dev_kfree_skb(skb);
564 		return;
565 	}
566 	ieee80211_add_tx_radiotap_header(sband, skb, retry_count, rtap_len);
567 
568 	/* XXX: is this sufficient for BPF? */
569 	skb_set_mac_header(skb, 0);
570 	skb->ip_summed = CHECKSUM_UNNECESSARY;
571 	skb->pkt_type = PACKET_OTHERHOST;
572 	skb->protocol = htons(ETH_P_802_2);
573 	memset(skb->cb, 0, sizeof(skb->cb));
574 
575 	rcu_read_lock();
576 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
577 		if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
578 			if (!ieee80211_sdata_running(sdata))
579 				continue;
580 
581 			if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
582 			    !send_to_cooked)
583 				continue;
584 
585 			if (prev_dev) {
586 				skb2 = skb_clone(skb, GFP_ATOMIC);
587 				if (skb2) {
588 					skb2->dev = prev_dev;
589 					netif_rx(skb2);
590 				}
591 			}
592 
593 			prev_dev = sdata->dev;
594 		}
595 	}
596 	if (prev_dev) {
597 		skb->dev = prev_dev;
598 		netif_rx(skb);
599 		skb = NULL;
600 	}
601 	rcu_read_unlock();
602 	dev_kfree_skb(skb);
603 }
604 EXPORT_SYMBOL(ieee80211_tx_status);
605 
606 void ieee80211_report_low_ack(struct ieee80211_sta *pubsta, u32 num_packets)
607 {
608 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
609 	cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
610 				    num_packets, GFP_ATOMIC);
611 }
612 EXPORT_SYMBOL(ieee80211_report_low_ack);
613