xref: /openbmc/linux/net/mac80211/status.c (revision 4ed91d48259d9ddd378424d008f2e6559f7e78f8)
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  * Copyright 2013-2014  Intel Mobile Communications GmbH
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12 
13 #include <linux/export.h>
14 #include <linux/etherdevice.h>
15 #include <net/mac80211.h>
16 #include <asm/unaligned.h>
17 #include "ieee80211_i.h"
18 #include "rate.h"
19 #include "mesh.h"
20 #include "led.h"
21 #include "wme.h"
22 
23 
24 void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
25 				 struct sk_buff *skb)
26 {
27 	struct ieee80211_local *local = hw_to_local(hw);
28 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
29 	int tmp;
30 
31 	skb->pkt_type = IEEE80211_TX_STATUS_MSG;
32 	skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
33 		       &local->skb_queue : &local->skb_queue_unreliable, skb);
34 	tmp = skb_queue_len(&local->skb_queue) +
35 		skb_queue_len(&local->skb_queue_unreliable);
36 	while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
37 	       (skb = skb_dequeue(&local->skb_queue_unreliable))) {
38 		ieee80211_free_txskb(hw, skb);
39 		tmp--;
40 		I802_DEBUG_INC(local->tx_status_drop);
41 	}
42 	tasklet_schedule(&local->tasklet);
43 }
44 EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);
45 
46 static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
47 					    struct sta_info *sta,
48 					    struct sk_buff *skb)
49 {
50 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
51 	struct ieee80211_hdr *hdr = (void *)skb->data;
52 	int ac;
53 
54 	if (info->flags & (IEEE80211_TX_CTL_NO_PS_BUFFER |
55 			   IEEE80211_TX_CTL_AMPDU)) {
56 		ieee80211_free_txskb(&local->hw, skb);
57 		return;
58 	}
59 
60 	/*
61 	 * This skb 'survived' a round-trip through the driver, and
62 	 * hopefully the driver didn't mangle it too badly. However,
63 	 * we can definitely not rely on the control information
64 	 * being correct. Clear it so we don't get junk there, and
65 	 * indicate that it needs new processing, but must not be
66 	 * modified/encrypted again.
67 	 */
68 	memset(&info->control, 0, sizeof(info->control));
69 
70 	info->control.jiffies = jiffies;
71 	info->control.vif = &sta->sdata->vif;
72 	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING |
73 		       IEEE80211_TX_INTFL_RETRANSMISSION;
74 	info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;
75 
76 	sta->status_stats.filtered++;
77 
78 	/*
79 	 * Clear more-data bit on filtered frames, it might be set
80 	 * but later frames might time out so it might have to be
81 	 * clear again ... It's all rather unlikely (this frame
82 	 * should time out first, right?) but let's not confuse
83 	 * peers unnecessarily.
84 	 */
85 	if (hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_MOREDATA))
86 		hdr->frame_control &= ~cpu_to_le16(IEEE80211_FCTL_MOREDATA);
87 
88 	if (ieee80211_is_data_qos(hdr->frame_control)) {
89 		u8 *p = ieee80211_get_qos_ctl(hdr);
90 		int tid = *p & IEEE80211_QOS_CTL_TID_MASK;
91 
92 		/*
93 		 * Clear EOSP if set, this could happen e.g.
94 		 * if an absence period (us being a P2P GO)
95 		 * shortens the SP.
96 		 */
97 		if (*p & IEEE80211_QOS_CTL_EOSP)
98 			*p &= ~IEEE80211_QOS_CTL_EOSP;
99 		ac = ieee80211_ac_from_tid(tid);
100 	} else {
101 		ac = IEEE80211_AC_BE;
102 	}
103 
104 	/*
105 	 * Clear the TX filter mask for this STA when sending the next
106 	 * packet. If the STA went to power save mode, this will happen
107 	 * when it wakes up for the next time.
108 	 */
109 	set_sta_flag(sta, WLAN_STA_CLEAR_PS_FILT);
110 	ieee80211_clear_fast_xmit(sta);
111 
112 	/*
113 	 * This code races in the following way:
114 	 *
115 	 *  (1) STA sends frame indicating it will go to sleep and does so
116 	 *  (2) hardware/firmware adds STA to filter list, passes frame up
117 	 *  (3) hardware/firmware processes TX fifo and suppresses a frame
118 	 *  (4) we get TX status before having processed the frame and
119 	 *	knowing that the STA has gone to sleep.
120 	 *
121 	 * This is actually quite unlikely even when both those events are
122 	 * processed from interrupts coming in quickly after one another or
123 	 * even at the same time because we queue both TX status events and
124 	 * RX frames to be processed by a tasklet and process them in the
125 	 * same order that they were received or TX status last. Hence, there
126 	 * is no race as long as the frame RX is processed before the next TX
127 	 * status, which drivers can ensure, see below.
128 	 *
129 	 * Note that this can only happen if the hardware or firmware can
130 	 * actually add STAs to the filter list, if this is done by the
131 	 * driver in response to set_tim() (which will only reduce the race
132 	 * this whole filtering tries to solve, not completely solve it)
133 	 * this situation cannot happen.
134 	 *
135 	 * To completely solve this race drivers need to make sure that they
136 	 *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
137 	 *	functions and
138 	 *  (b) always process RX events before TX status events if ordering
139 	 *      can be unknown, for example with different interrupt status
140 	 *	bits.
141 	 *  (c) if PS mode transitions are manual (i.e. the flag
142 	 *      %IEEE80211_HW_AP_LINK_PS is set), always process PS state
143 	 *      changes before calling TX status events if ordering can be
144 	 *	unknown.
145 	 */
146 	if (test_sta_flag(sta, WLAN_STA_PS_STA) &&
147 	    skb_queue_len(&sta->tx_filtered[ac]) < STA_MAX_TX_BUFFER) {
148 		skb_queue_tail(&sta->tx_filtered[ac], skb);
149 		sta_info_recalc_tim(sta);
150 
151 		if (!timer_pending(&local->sta_cleanup))
152 			mod_timer(&local->sta_cleanup,
153 				  round_jiffies(jiffies +
154 						STA_INFO_CLEANUP_INTERVAL));
155 		return;
156 	}
157 
158 	if (!test_sta_flag(sta, WLAN_STA_PS_STA) &&
159 	    !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
160 		/* Software retry the packet once */
161 		info->flags |= IEEE80211_TX_INTFL_RETRIED;
162 		ieee80211_add_pending_skb(local, skb);
163 		return;
164 	}
165 
166 	ps_dbg_ratelimited(sta->sdata,
167 			   "dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
168 			   skb_queue_len(&sta->tx_filtered[ac]),
169 			   !!test_sta_flag(sta, WLAN_STA_PS_STA), jiffies);
170 	ieee80211_free_txskb(&local->hw, skb);
171 }
172 
173 static void ieee80211_check_pending_bar(struct sta_info *sta, u8 *addr, u8 tid)
174 {
175 	struct tid_ampdu_tx *tid_tx;
176 
177 	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
178 	if (!tid_tx || !tid_tx->bar_pending)
179 		return;
180 
181 	tid_tx->bar_pending = false;
182 	ieee80211_send_bar(&sta->sdata->vif, addr, tid, tid_tx->failed_bar_ssn);
183 }
184 
185 static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
186 {
187 	struct ieee80211_mgmt *mgmt = (void *) skb->data;
188 	struct ieee80211_local *local = sta->local;
189 	struct ieee80211_sub_if_data *sdata = sta->sdata;
190 
191 	if (ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS))
192 		sta->status_stats.last_ack = jiffies;
193 
194 	if (ieee80211_is_data_qos(mgmt->frame_control)) {
195 		struct ieee80211_hdr *hdr = (void *) skb->data;
196 		u8 *qc = ieee80211_get_qos_ctl(hdr);
197 		u16 tid = qc[0] & 0xf;
198 
199 		ieee80211_check_pending_bar(sta, hdr->addr1, tid);
200 	}
201 
202 	if (ieee80211_is_action(mgmt->frame_control) &&
203 	    mgmt->u.action.category == WLAN_CATEGORY_HT &&
204 	    mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS &&
205 	    ieee80211_sdata_running(sdata)) {
206 		enum ieee80211_smps_mode smps_mode;
207 
208 		switch (mgmt->u.action.u.ht_smps.smps_control) {
209 		case WLAN_HT_SMPS_CONTROL_DYNAMIC:
210 			smps_mode = IEEE80211_SMPS_DYNAMIC;
211 			break;
212 		case WLAN_HT_SMPS_CONTROL_STATIC:
213 			smps_mode = IEEE80211_SMPS_STATIC;
214 			break;
215 		case WLAN_HT_SMPS_CONTROL_DISABLED:
216 		default: /* shouldn't happen since we don't send that */
217 			smps_mode = IEEE80211_SMPS_OFF;
218 			break;
219 		}
220 
221 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
222 			/*
223 			 * This update looks racy, but isn't -- if we come
224 			 * here we've definitely got a station that we're
225 			 * talking to, and on a managed interface that can
226 			 * only be the AP. And the only other place updating
227 			 * this variable in managed mode is before association.
228 			 */
229 			sdata->smps_mode = smps_mode;
230 			ieee80211_queue_work(&local->hw, &sdata->recalc_smps);
231 		} else if (sdata->vif.type == NL80211_IFTYPE_AP ||
232 			   sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
233 			sta->known_smps_mode = smps_mode;
234 		}
235 	}
236 }
237 
238 static void ieee80211_set_bar_pending(struct sta_info *sta, u8 tid, u16 ssn)
239 {
240 	struct tid_ampdu_tx *tid_tx;
241 
242 	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
243 	if (!tid_tx)
244 		return;
245 
246 	tid_tx->failed_bar_ssn = ssn;
247 	tid_tx->bar_pending = true;
248 }
249 
250 static int ieee80211_tx_radiotap_len(struct ieee80211_tx_info *info)
251 {
252 	int len = sizeof(struct ieee80211_radiotap_header);
253 
254 	/* IEEE80211_RADIOTAP_RATE rate */
255 	if (info->status.rates[0].idx >= 0 &&
256 	    !(info->status.rates[0].flags & (IEEE80211_TX_RC_MCS |
257 					     IEEE80211_TX_RC_VHT_MCS)))
258 		len += 2;
259 
260 	/* IEEE80211_RADIOTAP_TX_FLAGS */
261 	len += 2;
262 
263 	/* IEEE80211_RADIOTAP_DATA_RETRIES */
264 	len += 1;
265 
266 	/* IEEE80211_RADIOTAP_MCS
267 	 * IEEE80211_RADIOTAP_VHT */
268 	if (info->status.rates[0].idx >= 0) {
269 		if (info->status.rates[0].flags & IEEE80211_TX_RC_MCS)
270 			len += 3;
271 		else if (info->status.rates[0].flags & IEEE80211_TX_RC_VHT_MCS)
272 			len = ALIGN(len, 2) + 12;
273 	}
274 
275 	return len;
276 }
277 
278 static void
279 ieee80211_add_tx_radiotap_header(struct ieee80211_local *local,
280 				 struct ieee80211_supported_band *sband,
281 				 struct sk_buff *skb, int retry_count,
282 				 int rtap_len, int shift)
283 {
284 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
285 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
286 	struct ieee80211_radiotap_header *rthdr;
287 	unsigned char *pos;
288 	u16 txflags;
289 
290 	rthdr = (struct ieee80211_radiotap_header *) skb_push(skb, rtap_len);
291 
292 	memset(rthdr, 0, rtap_len);
293 	rthdr->it_len = cpu_to_le16(rtap_len);
294 	rthdr->it_present =
295 		cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
296 			    (1 << IEEE80211_RADIOTAP_DATA_RETRIES));
297 	pos = (unsigned char *)(rthdr + 1);
298 
299 	/*
300 	 * XXX: Once radiotap gets the bitmap reset thing the vendor
301 	 *	extensions proposal contains, we can actually report
302 	 *	the whole set of tries we did.
303 	 */
304 
305 	/* IEEE80211_RADIOTAP_RATE */
306 	if (info->status.rates[0].idx >= 0 &&
307 	    !(info->status.rates[0].flags & (IEEE80211_TX_RC_MCS |
308 					     IEEE80211_TX_RC_VHT_MCS))) {
309 		u16 rate;
310 
311 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
312 		rate = sband->bitrates[info->status.rates[0].idx].bitrate;
313 		*pos = DIV_ROUND_UP(rate, 5 * (1 << shift));
314 		/* padding for tx flags */
315 		pos += 2;
316 	}
317 
318 	/* IEEE80211_RADIOTAP_TX_FLAGS */
319 	txflags = 0;
320 	if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
321 	    !is_multicast_ether_addr(hdr->addr1))
322 		txflags |= IEEE80211_RADIOTAP_F_TX_FAIL;
323 
324 	if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT)
325 		txflags |= IEEE80211_RADIOTAP_F_TX_CTS;
326 	if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
327 		txflags |= IEEE80211_RADIOTAP_F_TX_RTS;
328 
329 	put_unaligned_le16(txflags, pos);
330 	pos += 2;
331 
332 	/* IEEE80211_RADIOTAP_DATA_RETRIES */
333 	/* for now report the total retry_count */
334 	*pos = retry_count;
335 	pos++;
336 
337 	if (info->status.rates[0].idx < 0)
338 		return;
339 
340 	/* IEEE80211_RADIOTAP_MCS
341 	 * IEEE80211_RADIOTAP_VHT */
342 	if (info->status.rates[0].flags & IEEE80211_TX_RC_MCS) {
343 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
344 		pos[0] = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
345 			 IEEE80211_RADIOTAP_MCS_HAVE_GI |
346 			 IEEE80211_RADIOTAP_MCS_HAVE_BW;
347 		if (info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
348 			pos[1] |= IEEE80211_RADIOTAP_MCS_SGI;
349 		if (info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
350 			pos[1] |= IEEE80211_RADIOTAP_MCS_BW_40;
351 		if (info->status.rates[0].flags & IEEE80211_TX_RC_GREEN_FIELD)
352 			pos[1] |= IEEE80211_RADIOTAP_MCS_FMT_GF;
353 		pos[2] = info->status.rates[0].idx;
354 		pos += 3;
355 	} else if (info->status.rates[0].flags & IEEE80211_TX_RC_VHT_MCS) {
356 		u16 known = local->hw.radiotap_vht_details &
357 			(IEEE80211_RADIOTAP_VHT_KNOWN_GI |
358 			 IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH);
359 
360 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_VHT);
361 
362 		/* required alignment from rthdr */
363 		pos = (u8 *)rthdr + ALIGN(pos - (u8 *)rthdr, 2);
364 
365 		/* u16 known - IEEE80211_RADIOTAP_VHT_KNOWN_* */
366 		put_unaligned_le16(known, pos);
367 		pos += 2;
368 
369 		/* u8 flags - IEEE80211_RADIOTAP_VHT_FLAG_* */
370 		if (info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
371 			*pos |= IEEE80211_RADIOTAP_VHT_FLAG_SGI;
372 		pos++;
373 
374 		/* u8 bandwidth */
375 		if (info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
376 			*pos = 1;
377 		else if (info->status.rates[0].flags & IEEE80211_TX_RC_80_MHZ_WIDTH)
378 			*pos = 4;
379 		else if (info->status.rates[0].flags & IEEE80211_TX_RC_160_MHZ_WIDTH)
380 			*pos = 11;
381 		else /* IEEE80211_TX_RC_{20_MHZ_WIDTH,FIXME:DUP_DATA} */
382 			*pos = 0;
383 		pos++;
384 
385 		/* u8 mcs_nss[4] */
386 		*pos = (ieee80211_rate_get_vht_mcs(&info->status.rates[0]) << 4) |
387 			ieee80211_rate_get_vht_nss(&info->status.rates[0]);
388 		pos += 4;
389 
390 		/* u8 coding */
391 		pos++;
392 		/* u8 group_id */
393 		pos++;
394 		/* u16 partial_aid */
395 		pos += 2;
396 	}
397 }
398 
399 /*
400  * Handles the tx for TDLS teardown frames.
401  * If the frame wasn't ACKed by the peer - it will be re-sent through the AP
402  */
403 static void ieee80211_tdls_td_tx_handle(struct ieee80211_local *local,
404 					struct ieee80211_sub_if_data *sdata,
405 					struct sk_buff *skb, u32 flags)
406 {
407 	struct sk_buff *teardown_skb;
408 	struct sk_buff *orig_teardown_skb;
409 	bool is_teardown = false;
410 
411 	/* Get the teardown data we need and free the lock */
412 	spin_lock(&sdata->u.mgd.teardown_lock);
413 	teardown_skb = sdata->u.mgd.teardown_skb;
414 	orig_teardown_skb = sdata->u.mgd.orig_teardown_skb;
415 	if ((skb == orig_teardown_skb) && teardown_skb) {
416 		sdata->u.mgd.teardown_skb = NULL;
417 		sdata->u.mgd.orig_teardown_skb = NULL;
418 		is_teardown = true;
419 	}
420 	spin_unlock(&sdata->u.mgd.teardown_lock);
421 
422 	if (is_teardown) {
423 		/* This mechanism relies on being able to get ACKs */
424 		WARN_ON(!ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS));
425 
426 		/* Check if peer has ACKed */
427 		if (flags & IEEE80211_TX_STAT_ACK) {
428 			dev_kfree_skb_any(teardown_skb);
429 		} else {
430 			tdls_dbg(sdata,
431 				 "TDLS Resending teardown through AP\n");
432 
433 			ieee80211_subif_start_xmit(teardown_skb, skb->dev);
434 		}
435 	}
436 }
437 
438 static struct ieee80211_sub_if_data *
439 ieee80211_sdata_from_skb(struct ieee80211_local *local, struct sk_buff *skb)
440 {
441 	struct ieee80211_sub_if_data *sdata;
442 
443 	if (skb->dev) {
444 		list_for_each_entry_rcu(sdata, &local->interfaces, list) {
445 			if (!sdata->dev)
446 				continue;
447 
448 			if (skb->dev == sdata->dev)
449 				return sdata;
450 		}
451 
452 		return NULL;
453 	}
454 
455 	return rcu_dereference(local->p2p_sdata);
456 }
457 
458 static void ieee80211_report_ack_skb(struct ieee80211_local *local,
459 				     struct ieee80211_tx_info *info,
460 				     bool acked, bool dropped)
461 {
462 	struct sk_buff *skb;
463 	unsigned long flags;
464 
465 	spin_lock_irqsave(&local->ack_status_lock, flags);
466 	skb = idr_remove(&local->ack_status_frames, info->ack_frame_id);
467 	spin_unlock_irqrestore(&local->ack_status_lock, flags);
468 
469 	if (!skb)
470 		return;
471 
472 	if (dropped) {
473 		dev_kfree_skb_any(skb);
474 		return;
475 	}
476 
477 	if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
478 		u64 cookie = IEEE80211_SKB_CB(skb)->ack.cookie;
479 		struct ieee80211_sub_if_data *sdata;
480 		struct ieee80211_hdr *hdr = (void *)skb->data;
481 
482 		rcu_read_lock();
483 		sdata = ieee80211_sdata_from_skb(local, skb);
484 		if (sdata) {
485 			if (ieee80211_is_nullfunc(hdr->frame_control) ||
486 			    ieee80211_is_qos_nullfunc(hdr->frame_control))
487 				cfg80211_probe_status(sdata->dev, hdr->addr1,
488 						      cookie, acked,
489 						      GFP_ATOMIC);
490 			else
491 				cfg80211_mgmt_tx_status(&sdata->wdev, cookie,
492 							skb->data, skb->len,
493 							acked, GFP_ATOMIC);
494 		}
495 		rcu_read_unlock();
496 
497 		dev_kfree_skb_any(skb);
498 	} else {
499 		/* consumes skb */
500 		skb_complete_wifi_ack(skb, acked);
501 	}
502 }
503 
504 static void ieee80211_report_used_skb(struct ieee80211_local *local,
505 				      struct sk_buff *skb, bool dropped)
506 {
507 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
508 	struct ieee80211_hdr *hdr = (void *)skb->data;
509 	bool acked = info->flags & IEEE80211_TX_STAT_ACK;
510 
511 	if (dropped)
512 		acked = false;
513 
514 	if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) {
515 		struct ieee80211_sub_if_data *sdata;
516 
517 		rcu_read_lock();
518 
519 		sdata = ieee80211_sdata_from_skb(local, skb);
520 
521 		if (!sdata) {
522 			skb->dev = NULL;
523 		} else {
524 			unsigned int hdr_size =
525 				ieee80211_hdrlen(hdr->frame_control);
526 
527 			/* Check to see if packet is a TDLS teardown packet */
528 			if (ieee80211_is_data(hdr->frame_control) &&
529 			    (ieee80211_get_tdls_action(skb, hdr_size) ==
530 			     WLAN_TDLS_TEARDOWN))
531 				ieee80211_tdls_td_tx_handle(local, sdata, skb,
532 							    info->flags);
533 			else
534 				ieee80211_mgd_conn_tx_status(sdata,
535 							     hdr->frame_control,
536 							     acked);
537 		}
538 
539 		rcu_read_unlock();
540 	} else if (info->ack_frame_id) {
541 		ieee80211_report_ack_skb(local, info, acked, dropped);
542 	}
543 
544 	if (!dropped && skb->destructor) {
545 		skb->wifi_acked_valid = 1;
546 		skb->wifi_acked = acked;
547 	}
548 }
549 
550 /*
551  * Use a static threshold for now, best value to be determined
552  * by testing ...
553  * Should it depend on:
554  *  - on # of retransmissions
555  *  - current throughput (higher value for higher tpt)?
556  */
557 #define STA_LOST_PKT_THRESHOLD	50
558 #define STA_LOST_TDLS_PKT_THRESHOLD	10
559 #define STA_LOST_TDLS_PKT_TIME		(10*HZ) /* 10secs since last ACK */
560 
561 static void ieee80211_lost_packet(struct sta_info *sta,
562 				  struct ieee80211_tx_info *info)
563 {
564 	/* If driver relies on its own algorithm for station kickout, skip
565 	 * mac80211 packet loss mechanism.
566 	 */
567 	if (ieee80211_hw_check(&sta->local->hw, REPORTS_LOW_ACK))
568 		return;
569 
570 	/* This packet was aggregated but doesn't carry status info */
571 	if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
572 	    !(info->flags & IEEE80211_TX_STAT_AMPDU))
573 		return;
574 
575 	sta->status_stats.lost_packets++;
576 	if (!sta->sta.tdls &&
577 	    sta->status_stats.lost_packets < STA_LOST_PKT_THRESHOLD)
578 		return;
579 
580 	/*
581 	 * If we're in TDLS mode, make sure that all STA_LOST_TDLS_PKT_THRESHOLD
582 	 * of the last packets were lost, and that no ACK was received in the
583 	 * last STA_LOST_TDLS_PKT_TIME ms, before triggering the CQM packet-loss
584 	 * mechanism.
585 	 */
586 	if (sta->sta.tdls &&
587 	    (sta->status_stats.lost_packets < STA_LOST_TDLS_PKT_THRESHOLD ||
588 	     time_before(jiffies,
589 			 sta->status_stats.last_tdls_pkt_time +
590 			 STA_LOST_TDLS_PKT_TIME)))
591 		return;
592 
593 	cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
594 				    sta->status_stats.lost_packets, GFP_ATOMIC);
595 	sta->status_stats.lost_packets = 0;
596 }
597 
598 static int ieee80211_tx_get_rates(struct ieee80211_hw *hw,
599 				  struct ieee80211_tx_info *info,
600 				  int *retry_count)
601 {
602 	int rates_idx = -1;
603 	int count = -1;
604 	int i;
605 
606 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
607 		if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
608 		    !(info->flags & IEEE80211_TX_STAT_AMPDU)) {
609 			/* just the first aggr frame carry status info */
610 			info->status.rates[i].idx = -1;
611 			info->status.rates[i].count = 0;
612 			break;
613 		} else if (info->status.rates[i].idx < 0) {
614 			break;
615 		} else if (i >= hw->max_report_rates) {
616 			/* the HW cannot have attempted that rate */
617 			info->status.rates[i].idx = -1;
618 			info->status.rates[i].count = 0;
619 			break;
620 		}
621 
622 		count += info->status.rates[i].count;
623 	}
624 	rates_idx = i - 1;
625 
626 	if (count < 0)
627 		count = 0;
628 
629 	*retry_count = count;
630 	return rates_idx;
631 }
632 
633 void ieee80211_tx_status_noskb(struct ieee80211_hw *hw,
634 			       struct ieee80211_sta *pubsta,
635 			       struct ieee80211_tx_info *info)
636 {
637 	struct ieee80211_local *local = hw_to_local(hw);
638 	struct ieee80211_supported_band *sband;
639 	int retry_count;
640 	bool acked, noack_success;
641 
642 	ieee80211_tx_get_rates(hw, info, &retry_count);
643 
644 	sband = hw->wiphy->bands[info->band];
645 
646 	acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
647 	noack_success = !!(info->flags & IEEE80211_TX_STAT_NOACK_TRANSMITTED);
648 
649 	if (pubsta) {
650 		struct sta_info *sta;
651 
652 		sta = container_of(pubsta, struct sta_info, sta);
653 
654 		if (!acked)
655 			sta->status_stats.retry_failed++;
656 		sta->status_stats.retry_count += retry_count;
657 
658 		if (acked) {
659 			sta->status_stats.last_ack = jiffies;
660 
661 			if (sta->status_stats.lost_packets)
662 				sta->status_stats.lost_packets = 0;
663 
664 			/* Track when last TDLS packet was ACKed */
665 			if (test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH))
666 				sta->status_stats.last_tdls_pkt_time = jiffies;
667 		} else {
668 			ieee80211_lost_packet(sta, info);
669 		}
670 
671 		rate_control_tx_status_noskb(local, sband, sta, info);
672 	}
673 
674 	if (acked || noack_success) {
675 		I802_DEBUG_INC(local->dot11TransmittedFrameCount);
676 		if (!pubsta)
677 			I802_DEBUG_INC(local->dot11MulticastTransmittedFrameCount);
678 		if (retry_count > 0)
679 			I802_DEBUG_INC(local->dot11RetryCount);
680 		if (retry_count > 1)
681 			I802_DEBUG_INC(local->dot11MultipleRetryCount);
682 	} else {
683 		I802_DEBUG_INC(local->dot11FailedCount);
684 	}
685 }
686 EXPORT_SYMBOL(ieee80211_tx_status_noskb);
687 
688 void ieee80211_tx_monitor(struct ieee80211_local *local, struct sk_buff *skb,
689 			  struct ieee80211_supported_band *sband,
690 			  int retry_count, int shift, bool send_to_cooked)
691 {
692 	struct sk_buff *skb2;
693 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
694 	struct ieee80211_sub_if_data *sdata;
695 	struct net_device *prev_dev = NULL;
696 	int rtap_len;
697 
698 	/* send frame to monitor interfaces now */
699 	rtap_len = ieee80211_tx_radiotap_len(info);
700 	if (WARN_ON_ONCE(skb_headroom(skb) < rtap_len)) {
701 		pr_err("ieee80211_tx_status: headroom too small\n");
702 		dev_kfree_skb(skb);
703 		return;
704 	}
705 	ieee80211_add_tx_radiotap_header(local, sband, skb, retry_count,
706 					 rtap_len, shift);
707 
708 	/* XXX: is this sufficient for BPF? */
709 	skb_reset_mac_header(skb);
710 	skb->ip_summed = CHECKSUM_UNNECESSARY;
711 	skb->pkt_type = PACKET_OTHERHOST;
712 	skb->protocol = htons(ETH_P_802_2);
713 	memset(skb->cb, 0, sizeof(skb->cb));
714 
715 	rcu_read_lock();
716 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
717 		if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
718 			if (!ieee80211_sdata_running(sdata))
719 				continue;
720 
721 			if ((sdata->u.mntr.flags & MONITOR_FLAG_COOK_FRAMES) &&
722 			    !send_to_cooked)
723 				continue;
724 
725 			if (prev_dev) {
726 				skb2 = skb_clone(skb, GFP_ATOMIC);
727 				if (skb2) {
728 					skb2->dev = prev_dev;
729 					netif_rx(skb2);
730 				}
731 			}
732 
733 			prev_dev = sdata->dev;
734 		}
735 	}
736 	if (prev_dev) {
737 		skb->dev = prev_dev;
738 		netif_rx(skb);
739 		skb = NULL;
740 	}
741 	rcu_read_unlock();
742 	dev_kfree_skb(skb);
743 }
744 
745 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
746 {
747 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
748 	struct ieee80211_local *local = hw_to_local(hw);
749 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
750 	__le16 fc;
751 	struct ieee80211_supported_band *sband;
752 	struct rhlist_head *tmp;
753 	struct sta_info *sta;
754 	int retry_count;
755 	int rates_idx;
756 	bool send_to_cooked;
757 	bool acked;
758 	struct ieee80211_bar *bar;
759 	int shift = 0;
760 	int tid = IEEE80211_NUM_TIDS;
761 
762 	rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);
763 
764 	rcu_read_lock();
765 
766 	sband = local->hw.wiphy->bands[info->band];
767 	fc = hdr->frame_control;
768 
769 	for_each_sta_info(local, hdr->addr1, sta, tmp) {
770 		/* skip wrong virtual interface */
771 		if (!ether_addr_equal(hdr->addr2, sta->sdata->vif.addr))
772 			continue;
773 
774 		shift = ieee80211_vif_get_shift(&sta->sdata->vif);
775 
776 		if (info->flags & IEEE80211_TX_STATUS_EOSP)
777 			clear_sta_flag(sta, WLAN_STA_SP);
778 
779 		acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
780 
781 		/* mesh Peer Service Period support */
782 		if (ieee80211_vif_is_mesh(&sta->sdata->vif) &&
783 		    ieee80211_is_data_qos(fc))
784 			ieee80211_mpsp_trigger_process(
785 				ieee80211_get_qos_ctl(hdr), sta, true, acked);
786 
787 		if (!acked && test_sta_flag(sta, WLAN_STA_PS_STA)) {
788 			/*
789 			 * The STA is in power save mode, so assume
790 			 * that this TX packet failed because of that.
791 			 */
792 			ieee80211_handle_filtered_frame(local, sta, skb);
793 			rcu_read_unlock();
794 			return;
795 		}
796 
797 		if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL) &&
798 		    (ieee80211_is_data(hdr->frame_control)) &&
799 		    (rates_idx != -1))
800 			sta->tx_stats.last_rate =
801 				info->status.rates[rates_idx];
802 
803 		if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
804 		    (ieee80211_is_data_qos(fc))) {
805 			u16 ssn;
806 			u8 *qc;
807 
808 			qc = ieee80211_get_qos_ctl(hdr);
809 			tid = qc[0] & 0xf;
810 			ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
811 						& IEEE80211_SCTL_SEQ);
812 			ieee80211_send_bar(&sta->sdata->vif, hdr->addr1,
813 					   tid, ssn);
814 		} else if (ieee80211_is_data_qos(fc)) {
815 			u8 *qc = ieee80211_get_qos_ctl(hdr);
816 
817 			tid = qc[0] & 0xf;
818 		}
819 
820 		if (!acked && ieee80211_is_back_req(fc)) {
821 			u16 control;
822 
823 			/*
824 			 * BAR failed, store the last SSN and retry sending
825 			 * the BAR when the next unicast transmission on the
826 			 * same TID succeeds.
827 			 */
828 			bar = (struct ieee80211_bar *) skb->data;
829 			control = le16_to_cpu(bar->control);
830 			if (!(control & IEEE80211_BAR_CTRL_MULTI_TID)) {
831 				u16 ssn = le16_to_cpu(bar->start_seq_num);
832 
833 				tid = (control &
834 				       IEEE80211_BAR_CTRL_TID_INFO_MASK) >>
835 				      IEEE80211_BAR_CTRL_TID_INFO_SHIFT;
836 
837 				ieee80211_set_bar_pending(sta, tid, ssn);
838 			}
839 		}
840 
841 		if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
842 			ieee80211_handle_filtered_frame(local, sta, skb);
843 			rcu_read_unlock();
844 			return;
845 		} else {
846 			if (!acked)
847 				sta->status_stats.retry_failed++;
848 			sta->status_stats.retry_count += retry_count;
849 
850 			if (ieee80211_is_data_present(fc)) {
851 				if (!acked)
852 					sta->status_stats.msdu_failed[tid]++;
853 
854 				sta->status_stats.msdu_retries[tid] +=
855 					retry_count;
856 			}
857 		}
858 
859 		rate_control_tx_status(local, sband, sta, skb);
860 		if (ieee80211_vif_is_mesh(&sta->sdata->vif))
861 			ieee80211s_update_metric(local, sta, skb);
862 
863 		if (!(info->flags & IEEE80211_TX_CTL_INJECTED) && acked)
864 			ieee80211_frame_acked(sta, skb);
865 
866 		if ((sta->sdata->vif.type == NL80211_IFTYPE_STATION) &&
867 		    ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS))
868 			ieee80211_sta_tx_notify(sta->sdata, (void *) skb->data,
869 						acked, info->status.tx_time);
870 
871 		if (ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS)) {
872 			if (info->flags & IEEE80211_TX_STAT_ACK) {
873 				if (sta->status_stats.lost_packets)
874 					sta->status_stats.lost_packets = 0;
875 
876 				/* Track when last TDLS packet was ACKed */
877 				if (test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH))
878 					sta->status_stats.last_tdls_pkt_time =
879 						jiffies;
880 			} else {
881 				ieee80211_lost_packet(sta, info);
882 			}
883 		}
884 	}
885 
886 	rcu_read_unlock();
887 
888 	ieee80211_led_tx(local);
889 
890 	/* SNMP counters
891 	 * Fragments are passed to low-level drivers as separate skbs, so these
892 	 * are actually fragments, not frames. Update frame counters only for
893 	 * the first fragment of the frame. */
894 	if ((info->flags & IEEE80211_TX_STAT_ACK) ||
895 	    (info->flags & IEEE80211_TX_STAT_NOACK_TRANSMITTED)) {
896 		if (ieee80211_is_first_frag(hdr->seq_ctrl)) {
897 			I802_DEBUG_INC(local->dot11TransmittedFrameCount);
898 			if (is_multicast_ether_addr(ieee80211_get_DA(hdr)))
899 				I802_DEBUG_INC(local->dot11MulticastTransmittedFrameCount);
900 			if (retry_count > 0)
901 				I802_DEBUG_INC(local->dot11RetryCount);
902 			if (retry_count > 1)
903 				I802_DEBUG_INC(local->dot11MultipleRetryCount);
904 		}
905 
906 		/* This counter shall be incremented for an acknowledged MPDU
907 		 * with an individual address in the address 1 field or an MPDU
908 		 * with a multicast address in the address 1 field of type Data
909 		 * or Management. */
910 		if (!is_multicast_ether_addr(hdr->addr1) ||
911 		    ieee80211_is_data(fc) ||
912 		    ieee80211_is_mgmt(fc))
913 			I802_DEBUG_INC(local->dot11TransmittedFragmentCount);
914 	} else {
915 		if (ieee80211_is_first_frag(hdr->seq_ctrl))
916 			I802_DEBUG_INC(local->dot11FailedCount);
917 	}
918 
919 	if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
920 	    ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS) &&
921 	    !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
922 	    local->ps_sdata && !(local->scanning)) {
923 		if (info->flags & IEEE80211_TX_STAT_ACK) {
924 			local->ps_sdata->u.mgd.flags |=
925 					IEEE80211_STA_NULLFUNC_ACKED;
926 		} else
927 			mod_timer(&local->dynamic_ps_timer, jiffies +
928 					msecs_to_jiffies(10));
929 	}
930 
931 	ieee80211_report_used_skb(local, skb, false);
932 
933 	/* this was a transmitted frame, but now we want to reuse it */
934 	skb_orphan(skb);
935 
936 	/* Need to make a copy before skb->cb gets cleared */
937 	send_to_cooked = !!(info->flags & IEEE80211_TX_CTL_INJECTED) ||
938 			 !(ieee80211_is_data(fc));
939 
940 	/*
941 	 * This is a bit racy but we can avoid a lot of work
942 	 * with this test...
943 	 */
944 	if (!local->monitors && (!send_to_cooked || !local->cooked_mntrs)) {
945 		dev_kfree_skb(skb);
946 		return;
947 	}
948 
949 	/* send to monitor interfaces */
950 	ieee80211_tx_monitor(local, skb, sband, retry_count, shift, send_to_cooked);
951 }
952 EXPORT_SYMBOL(ieee80211_tx_status);
953 
954 void ieee80211_report_low_ack(struct ieee80211_sta *pubsta, u32 num_packets)
955 {
956 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
957 	cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
958 				    num_packets, GFP_ATOMIC);
959 }
960 EXPORT_SYMBOL(ieee80211_report_low_ack);
961 
962 void ieee80211_free_txskb(struct ieee80211_hw *hw, struct sk_buff *skb)
963 {
964 	struct ieee80211_local *local = hw_to_local(hw);
965 
966 	ieee80211_report_used_skb(local, skb, true);
967 	dev_kfree_skb_any(skb);
968 }
969 EXPORT_SYMBOL(ieee80211_free_txskb);
970 
971 void ieee80211_purge_tx_queue(struct ieee80211_hw *hw,
972 			      struct sk_buff_head *skbs)
973 {
974 	struct sk_buff *skb;
975 
976 	while ((skb = __skb_dequeue(skbs)))
977 		ieee80211_free_txskb(hw, skb);
978 }
979