xref: /linux/net/mac80211/agg-tx.c (revision 5bdef865eb358b6f3760e25e591ae115e9eeddef)
1 /*
2  * HT handling
3  *
4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
5  * Copyright 2002-2005, Instant802 Networks, Inc.
6  * Copyright 2005-2006, Devicescape Software, Inc.
7  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
9  * Copyright 2007-2009, Intel Corporation
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  */
15 
16 #include <linux/ieee80211.h>
17 #include <net/mac80211.h>
18 #include "ieee80211_i.h"
19 #include "driver-ops.h"
20 #include "wme.h"
21 
22 /**
23  * DOC: TX aggregation
24  *
25  * Aggregation on the TX side requires setting the hardware flag
26  * %IEEE80211_HW_AMPDU_AGGREGATION as well as, if present, the @ampdu_queues
27  * hardware parameter to the number of hardware AMPDU queues. If there are no
28  * hardware queues then the driver will (currently) have to do all frame
29  * buffering.
30  *
31  * When TX aggregation is started by some subsystem (usually the rate control
32  * algorithm would be appropriate) by calling the
33  * ieee80211_start_tx_ba_session() function, the driver will be notified via
34  * its @ampdu_action function, with the %IEEE80211_AMPDU_TX_START action.
35  *
36  * In response to that, the driver is later required to call the
37  * ieee80211_start_tx_ba_cb() (or ieee80211_start_tx_ba_cb_irqsafe())
38  * function, which will start the aggregation session.
39  *
40  * Similarly, when the aggregation session is stopped by
41  * ieee80211_stop_tx_ba_session(), the driver's @ampdu_action function will
42  * be called with the action %IEEE80211_AMPDU_TX_STOP. In this case, the
43  * call must not fail, and the driver must later call ieee80211_stop_tx_ba_cb()
44  * (or ieee80211_stop_tx_ba_cb_irqsafe()).
45  */
46 
47 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
48 					 const u8 *da, u16 tid,
49 					 u8 dialog_token, u16 start_seq_num,
50 					 u16 agg_size, u16 timeout)
51 {
52 	struct ieee80211_local *local = sdata->local;
53 	struct sk_buff *skb;
54 	struct ieee80211_mgmt *mgmt;
55 	u16 capab;
56 
57 	skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
58 
59 	if (!skb) {
60 		printk(KERN_ERR "%s: failed to allocate buffer "
61 				"for addba request frame\n", sdata->dev->name);
62 		return;
63 	}
64 	skb_reserve(skb, local->hw.extra_tx_headroom);
65 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
66 	memset(mgmt, 0, 24);
67 	memcpy(mgmt->da, da, ETH_ALEN);
68 	memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
69 	if (sdata->vif.type == NL80211_IFTYPE_AP ||
70 	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
71 		memcpy(mgmt->bssid, sdata->dev->dev_addr, ETH_ALEN);
72 	else if (sdata->vif.type == NL80211_IFTYPE_STATION)
73 		memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
74 
75 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
76 					  IEEE80211_STYPE_ACTION);
77 
78 	skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
79 
80 	mgmt->u.action.category = WLAN_CATEGORY_BACK;
81 	mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
82 
83 	mgmt->u.action.u.addba_req.dialog_token = dialog_token;
84 	capab = (u16)(1 << 1);		/* bit 1 aggregation policy */
85 	capab |= (u16)(tid << 2); 	/* bit 5:2 TID number */
86 	capab |= (u16)(agg_size << 6);	/* bit 15:6 max size of aggergation */
87 
88 	mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
89 
90 	mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
91 	mgmt->u.action.u.addba_req.start_seq_num =
92 					cpu_to_le16(start_seq_num << 4);
93 
94 	ieee80211_tx_skb(sdata, skb, 1);
95 }
96 
97 void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u16 ssn)
98 {
99 	struct ieee80211_local *local = sdata->local;
100 	struct sk_buff *skb;
101 	struct ieee80211_bar *bar;
102 	u16 bar_control = 0;
103 
104 	skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
105 	if (!skb) {
106 		printk(KERN_ERR "%s: failed to allocate buffer for "
107 			"bar frame\n", sdata->dev->name);
108 		return;
109 	}
110 	skb_reserve(skb, local->hw.extra_tx_headroom);
111 	bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
112 	memset(bar, 0, sizeof(*bar));
113 	bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
114 					 IEEE80211_STYPE_BACK_REQ);
115 	memcpy(bar->ra, ra, ETH_ALEN);
116 	memcpy(bar->ta, sdata->dev->dev_addr, ETH_ALEN);
117 	bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
118 	bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
119 	bar_control |= (u16)(tid << 12);
120 	bar->control = cpu_to_le16(bar_control);
121 	bar->start_seq_num = cpu_to_le16(ssn);
122 
123 	ieee80211_tx_skb(sdata, skb, 0);
124 }
125 
126 static int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
127 					   enum ieee80211_back_parties initiator)
128 {
129 	struct ieee80211_local *local = sta->local;
130 	int ret;
131 	u8 *state;
132 
133 	state = &sta->ampdu_mlme.tid_state_tx[tid];
134 
135 	if (*state == HT_AGG_STATE_OPERATIONAL)
136 		sta->ampdu_mlme.addba_req_num[tid] = 0;
137 
138 	*state = HT_AGG_STATE_REQ_STOP_BA_MSK |
139 		(initiator << HT_AGG_STATE_INITIATOR_SHIFT);
140 
141 	ret = drv_ampdu_action(local, IEEE80211_AMPDU_TX_STOP,
142 			       &sta->sta, tid, NULL);
143 
144 	/* HW shall not deny going back to legacy */
145 	if (WARN_ON(ret)) {
146 		*state = HT_AGG_STATE_OPERATIONAL;
147 		/*
148 		 * We may have pending packets get stuck in this case...
149 		 * Not bothering with a workaround for now.
150 		 */
151 	}
152 
153 	return ret;
154 }
155 
156 /*
157  * After sending add Block Ack request we activated a timer until
158  * add Block Ack response will arrive from the recipient.
159  * If this timer expires sta_addba_resp_timer_expired will be executed.
160  */
161 static void sta_addba_resp_timer_expired(unsigned long data)
162 {
163 	/* not an elegant detour, but there is no choice as the timer passes
164 	 * only one argument, and both sta_info and TID are needed, so init
165 	 * flow in sta_info_create gives the TID as data, while the timer_to_id
166 	 * array gives the sta through container_of */
167 	u16 tid = *(u8 *)data;
168 	struct sta_info *sta = container_of((void *)data,
169 		struct sta_info, timer_to_tid[tid]);
170 	u8 *state;
171 
172 	state = &sta->ampdu_mlme.tid_state_tx[tid];
173 
174 	/* check if the TID waits for addBA response */
175 	spin_lock_bh(&sta->lock);
176 	if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
177 		spin_unlock_bh(&sta->lock);
178 		*state = HT_AGG_STATE_IDLE;
179 #ifdef CONFIG_MAC80211_HT_DEBUG
180 		printk(KERN_DEBUG "timer expired on tid %d but we are not "
181 				"expecting addBA response there", tid);
182 #endif
183 		return;
184 	}
185 
186 #ifdef CONFIG_MAC80211_HT_DEBUG
187 	printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
188 #endif
189 
190 	___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
191 	spin_unlock_bh(&sta->lock);
192 }
193 
194 static inline int ieee80211_ac_from_tid(int tid)
195 {
196 	return ieee802_1d_to_ac[tid & 7];
197 }
198 
199 int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
200 {
201 	struct ieee80211_local *local = hw_to_local(hw);
202 	struct sta_info *sta;
203 	struct ieee80211_sub_if_data *sdata;
204 	u8 *state;
205 	int ret = 0;
206 	u16 start_seq_num;
207 
208 	if (WARN_ON(!local->ops->ampdu_action))
209 		return -EINVAL;
210 
211 	if ((tid >= STA_TID_NUM) || !(hw->flags & IEEE80211_HW_AMPDU_AGGREGATION))
212 		return -EINVAL;
213 
214 #ifdef CONFIG_MAC80211_HT_DEBUG
215 	printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
216 	       ra, tid);
217 #endif /* CONFIG_MAC80211_HT_DEBUG */
218 
219 	rcu_read_lock();
220 
221 	sta = sta_info_get(local, ra);
222 	if (!sta) {
223 #ifdef CONFIG_MAC80211_HT_DEBUG
224 		printk(KERN_DEBUG "Could not find the station\n");
225 #endif
226 		ret = -ENOENT;
227 		goto unlock;
228 	}
229 
230 	/*
231 	 * The aggregation code is not prepared to handle
232 	 * anything but STA/AP due to the BSSID handling.
233 	 * IBSS could work in the code but isn't supported
234 	 * by drivers or the standard.
235 	 */
236 	if (sta->sdata->vif.type != NL80211_IFTYPE_STATION &&
237 	    sta->sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
238 	    sta->sdata->vif.type != NL80211_IFTYPE_AP) {
239 		ret = -EINVAL;
240 		goto unlock;
241 	}
242 
243 	if (test_sta_flags(sta, WLAN_STA_SUSPEND)) {
244 #ifdef CONFIG_MAC80211_HT_DEBUG
245 		printk(KERN_DEBUG "Suspend in progress. "
246 		       "Denying BA session request\n");
247 #endif
248 		ret = -EINVAL;
249 		goto unlock;
250 	}
251 
252 	spin_lock_bh(&sta->lock);
253 	spin_lock(&local->ampdu_lock);
254 
255 	sdata = sta->sdata;
256 
257 	/* we have tried too many times, receiver does not want A-MPDU */
258 	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
259 		ret = -EBUSY;
260 		goto err_unlock_sta;
261 	}
262 
263 	state = &sta->ampdu_mlme.tid_state_tx[tid];
264 	/* check if the TID is not in aggregation flow already */
265 	if (*state != HT_AGG_STATE_IDLE) {
266 #ifdef CONFIG_MAC80211_HT_DEBUG
267 		printk(KERN_DEBUG "BA request denied - session is not "
268 				 "idle on tid %u\n", tid);
269 #endif /* CONFIG_MAC80211_HT_DEBUG */
270 		ret = -EAGAIN;
271 		goto err_unlock_sta;
272 	}
273 
274 	/*
275 	 * While we're asking the driver about the aggregation,
276 	 * stop the AC queue so that we don't have to worry
277 	 * about frames that came in while we were doing that,
278 	 * which would require us to put them to the AC pending
279 	 * afterwards which just makes the code more complex.
280 	 */
281 	ieee80211_stop_queue_by_reason(
282 		&local->hw, ieee80211_ac_from_tid(tid),
283 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
284 
285 	/* prepare A-MPDU MLME for Tx aggregation */
286 	sta->ampdu_mlme.tid_tx[tid] =
287 			kmalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
288 	if (!sta->ampdu_mlme.tid_tx[tid]) {
289 #ifdef CONFIG_MAC80211_HT_DEBUG
290 		if (net_ratelimit())
291 			printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
292 					tid);
293 #endif
294 		ret = -ENOMEM;
295 		goto err_wake_queue;
296 	}
297 
298 	skb_queue_head_init(&sta->ampdu_mlme.tid_tx[tid]->pending);
299 
300 	/* Tx timer */
301 	sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.function =
302 			sta_addba_resp_timer_expired;
303 	sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.data =
304 			(unsigned long)&sta->timer_to_tid[tid];
305 	init_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
306 
307 	/* Ok, the Addba frame hasn't been sent yet, but if the driver calls the
308 	 * call back right away, it must see that the flow has begun */
309 	*state |= HT_ADDBA_REQUESTED_MSK;
310 
311 	start_seq_num = sta->tid_seq[tid];
312 
313 	ret = drv_ampdu_action(local, IEEE80211_AMPDU_TX_START,
314 			       &sta->sta, tid, &start_seq_num);
315 
316 	if (ret) {
317 #ifdef CONFIG_MAC80211_HT_DEBUG
318 		printk(KERN_DEBUG "BA request denied - HW unavailable for"
319 					" tid %d\n", tid);
320 #endif /* CONFIG_MAC80211_HT_DEBUG */
321 		*state = HT_AGG_STATE_IDLE;
322 		goto err_free;
323 	}
324 
325 	/* Driver vetoed or OKed, but we can take packets again now */
326 	ieee80211_wake_queue_by_reason(
327 		&local->hw, ieee80211_ac_from_tid(tid),
328 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
329 
330 	spin_unlock(&local->ampdu_lock);
331 	spin_unlock_bh(&sta->lock);
332 
333 	/* send an addBA request */
334 	sta->ampdu_mlme.dialog_token_allocator++;
335 	sta->ampdu_mlme.tid_tx[tid]->dialog_token =
336 			sta->ampdu_mlme.dialog_token_allocator;
337 	sta->ampdu_mlme.tid_tx[tid]->ssn = start_seq_num;
338 
339 	ieee80211_send_addba_request(sta->sdata, ra, tid,
340 			 sta->ampdu_mlme.tid_tx[tid]->dialog_token,
341 			 sta->ampdu_mlme.tid_tx[tid]->ssn,
342 			 0x40, 5000);
343 	sta->ampdu_mlme.addba_req_num[tid]++;
344 	/* activate the timer for the recipient's addBA response */
345 	sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
346 				jiffies + ADDBA_RESP_INTERVAL;
347 	add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
348 #ifdef CONFIG_MAC80211_HT_DEBUG
349 	printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
350 #endif
351 	goto unlock;
352 
353  err_free:
354 	kfree(sta->ampdu_mlme.tid_tx[tid]);
355 	sta->ampdu_mlme.tid_tx[tid] = NULL;
356  err_wake_queue:
357 	ieee80211_wake_queue_by_reason(
358 		&local->hw, ieee80211_ac_from_tid(tid),
359 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
360  err_unlock_sta:
361 	spin_unlock(&local->ampdu_lock);
362 	spin_unlock_bh(&sta->lock);
363  unlock:
364 	rcu_read_unlock();
365 	return ret;
366 }
367 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
368 
369 /*
370  * splice packets from the STA's pending to the local pending,
371  * requires a call to ieee80211_agg_splice_finish and holding
372  * local->ampdu_lock across both calls.
373  */
374 static void ieee80211_agg_splice_packets(struct ieee80211_local *local,
375 					 struct sta_info *sta, u16 tid)
376 {
377 	unsigned long flags;
378 	u16 queue = ieee80211_ac_from_tid(tid);
379 
380 	ieee80211_stop_queue_by_reason(
381 		&local->hw, queue,
382 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
383 
384 	if (!skb_queue_empty(&sta->ampdu_mlme.tid_tx[tid]->pending)) {
385 		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
386 		/* mark queue as pending, it is stopped already */
387 		__set_bit(IEEE80211_QUEUE_STOP_REASON_PENDING,
388 			  &local->queue_stop_reasons[queue]);
389 		/* copy over remaining packets */
390 		skb_queue_splice_tail_init(
391 			&sta->ampdu_mlme.tid_tx[tid]->pending,
392 			&local->pending[queue]);
393 		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
394 	}
395 }
396 
397 static void ieee80211_agg_splice_finish(struct ieee80211_local *local,
398 					struct sta_info *sta, u16 tid)
399 {
400 	u16 queue = ieee80211_ac_from_tid(tid);
401 
402 	ieee80211_wake_queue_by_reason(
403 		&local->hw, queue,
404 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
405 }
406 
407 /* caller must hold sta->lock */
408 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
409 					 struct sta_info *sta, u16 tid)
410 {
411 #ifdef CONFIG_MAC80211_HT_DEBUG
412 	printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
413 #endif
414 
415 	spin_lock(&local->ampdu_lock);
416 	ieee80211_agg_splice_packets(local, sta, tid);
417 	/*
418 	 * NB: we rely on sta->lock being taken in the TX
419 	 * processing here when adding to the pending queue,
420 	 * otherwise we could only change the state of the
421 	 * session to OPERATIONAL _here_.
422 	 */
423 	ieee80211_agg_splice_finish(local, sta, tid);
424 	spin_unlock(&local->ampdu_lock);
425 
426 	drv_ampdu_action(local, IEEE80211_AMPDU_TX_OPERATIONAL,
427 			 &sta->sta, tid, NULL);
428 }
429 
430 void ieee80211_start_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u16 tid)
431 {
432 	struct ieee80211_local *local = hw_to_local(hw);
433 	struct sta_info *sta;
434 	u8 *state;
435 
436 	if (tid >= STA_TID_NUM) {
437 #ifdef CONFIG_MAC80211_HT_DEBUG
438 		printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
439 				tid, STA_TID_NUM);
440 #endif
441 		return;
442 	}
443 
444 	rcu_read_lock();
445 	sta = sta_info_get(local, ra);
446 	if (!sta) {
447 		rcu_read_unlock();
448 #ifdef CONFIG_MAC80211_HT_DEBUG
449 		printk(KERN_DEBUG "Could not find station: %pM\n", ra);
450 #endif
451 		return;
452 	}
453 
454 	state = &sta->ampdu_mlme.tid_state_tx[tid];
455 	spin_lock_bh(&sta->lock);
456 
457 	if (WARN_ON(!(*state & HT_ADDBA_REQUESTED_MSK))) {
458 #ifdef CONFIG_MAC80211_HT_DEBUG
459 		printk(KERN_DEBUG "addBA was not requested yet, state is %d\n",
460 				*state);
461 #endif
462 		spin_unlock_bh(&sta->lock);
463 		rcu_read_unlock();
464 		return;
465 	}
466 
467 	if (WARN_ON(*state & HT_ADDBA_DRV_READY_MSK))
468 		goto out;
469 
470 	*state |= HT_ADDBA_DRV_READY_MSK;
471 
472 	if (*state == HT_AGG_STATE_OPERATIONAL)
473 		ieee80211_agg_tx_operational(local, sta, tid);
474 
475  out:
476 	spin_unlock_bh(&sta->lock);
477 	rcu_read_unlock();
478 }
479 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb);
480 
481 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
482 				      const u8 *ra, u16 tid)
483 {
484 	struct ieee80211_local *local = hw_to_local(hw);
485 	struct ieee80211_ra_tid *ra_tid;
486 	struct sk_buff *skb = dev_alloc_skb(0);
487 
488 	if (unlikely(!skb)) {
489 #ifdef CONFIG_MAC80211_HT_DEBUG
490 		if (net_ratelimit())
491 			printk(KERN_WARNING "%s: Not enough memory, "
492 			       "dropping start BA session", skb->dev->name);
493 #endif
494 		return;
495 	}
496 	ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
497 	memcpy(&ra_tid->ra, ra, ETH_ALEN);
498 	ra_tid->tid = tid;
499 
500 	skb->pkt_type = IEEE80211_ADDBA_MSG;
501 	skb_queue_tail(&local->skb_queue, skb);
502 	tasklet_schedule(&local->tasklet);
503 }
504 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
505 
506 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
507 				   enum ieee80211_back_parties initiator)
508 {
509 	u8 *state;
510 	int ret;
511 
512 	/* check if the TID is in aggregation */
513 	state = &sta->ampdu_mlme.tid_state_tx[tid];
514 	spin_lock_bh(&sta->lock);
515 
516 	if (*state != HT_AGG_STATE_OPERATIONAL) {
517 		ret = -ENOENT;
518 		goto unlock;
519 	}
520 
521 #ifdef CONFIG_MAC80211_HT_DEBUG
522 	printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
523 	       sta->sta.addr, tid);
524 #endif /* CONFIG_MAC80211_HT_DEBUG */
525 
526 	ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator);
527 
528  unlock:
529 	spin_unlock_bh(&sta->lock);
530 	return ret;
531 }
532 
533 int ieee80211_stop_tx_ba_session(struct ieee80211_hw *hw,
534 				 u8 *ra, u16 tid,
535 				 enum ieee80211_back_parties initiator)
536 {
537 	struct ieee80211_local *local = hw_to_local(hw);
538 	struct sta_info *sta;
539 	int ret = 0;
540 
541 	if (WARN_ON(!local->ops->ampdu_action))
542 		return -EINVAL;
543 
544 	if (tid >= STA_TID_NUM)
545 		return -EINVAL;
546 
547 	rcu_read_lock();
548 	sta = sta_info_get(local, ra);
549 	if (!sta) {
550 		rcu_read_unlock();
551 		return -ENOENT;
552 	}
553 
554 	ret = __ieee80211_stop_tx_ba_session(sta, tid, initiator);
555 	rcu_read_unlock();
556 	return ret;
557 }
558 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
559 
560 void ieee80211_stop_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u8 tid)
561 {
562 	struct ieee80211_local *local = hw_to_local(hw);
563 	struct sta_info *sta;
564 	u8 *state;
565 
566 	if (tid >= STA_TID_NUM) {
567 #ifdef CONFIG_MAC80211_HT_DEBUG
568 		printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
569 				tid, STA_TID_NUM);
570 #endif
571 		return;
572 	}
573 
574 #ifdef CONFIG_MAC80211_HT_DEBUG
575 	printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
576 	       ra, tid);
577 #endif /* CONFIG_MAC80211_HT_DEBUG */
578 
579 	rcu_read_lock();
580 	sta = sta_info_get(local, ra);
581 	if (!sta) {
582 #ifdef CONFIG_MAC80211_HT_DEBUG
583 		printk(KERN_DEBUG "Could not find station: %pM\n", ra);
584 #endif
585 		rcu_read_unlock();
586 		return;
587 	}
588 	state = &sta->ampdu_mlme.tid_state_tx[tid];
589 
590 	/* NOTE: no need to use sta->lock in this state check, as
591 	 * ieee80211_stop_tx_ba_session will let only one stop call to
592 	 * pass through per sta/tid
593 	 */
594 	if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) {
595 #ifdef CONFIG_MAC80211_HT_DEBUG
596 		printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
597 #endif
598 		rcu_read_unlock();
599 		return;
600 	}
601 
602 	if (*state & HT_AGG_STATE_INITIATOR_MSK)
603 		ieee80211_send_delba(sta->sdata, ra, tid,
604 			WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
605 
606 	spin_lock_bh(&sta->lock);
607 	spin_lock(&local->ampdu_lock);
608 
609 	ieee80211_agg_splice_packets(local, sta, tid);
610 
611 	*state = HT_AGG_STATE_IDLE;
612 	/* from now on packets are no longer put onto sta->pending */
613 	kfree(sta->ampdu_mlme.tid_tx[tid]);
614 	sta->ampdu_mlme.tid_tx[tid] = NULL;
615 
616 	ieee80211_agg_splice_finish(local, sta, tid);
617 
618 	spin_unlock(&local->ampdu_lock);
619 	spin_unlock_bh(&sta->lock);
620 
621 	rcu_read_unlock();
622 }
623 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb);
624 
625 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
626 				     const u8 *ra, u16 tid)
627 {
628 	struct ieee80211_local *local = hw_to_local(hw);
629 	struct ieee80211_ra_tid *ra_tid;
630 	struct sk_buff *skb = dev_alloc_skb(0);
631 
632 	if (unlikely(!skb)) {
633 #ifdef CONFIG_MAC80211_HT_DEBUG
634 		if (net_ratelimit())
635 			printk(KERN_WARNING "%s: Not enough memory, "
636 			       "dropping stop BA session", skb->dev->name);
637 #endif
638 		return;
639 	}
640 	ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
641 	memcpy(&ra_tid->ra, ra, ETH_ALEN);
642 	ra_tid->tid = tid;
643 
644 	skb->pkt_type = IEEE80211_DELBA_MSG;
645 	skb_queue_tail(&local->skb_queue, skb);
646 	tasklet_schedule(&local->tasklet);
647 }
648 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
649 
650 
651 void ieee80211_process_addba_resp(struct ieee80211_local *local,
652 				  struct sta_info *sta,
653 				  struct ieee80211_mgmt *mgmt,
654 				  size_t len)
655 {
656 	u16 capab, tid;
657 	u8 *state;
658 
659 	capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
660 	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
661 
662 	state = &sta->ampdu_mlme.tid_state_tx[tid];
663 
664 	spin_lock_bh(&sta->lock);
665 
666 	if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
667 		spin_unlock_bh(&sta->lock);
668 		return;
669 	}
670 
671 	if (mgmt->u.action.u.addba_resp.dialog_token !=
672 		sta->ampdu_mlme.tid_tx[tid]->dialog_token) {
673 		spin_unlock_bh(&sta->lock);
674 #ifdef CONFIG_MAC80211_HT_DEBUG
675 		printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
676 #endif /* CONFIG_MAC80211_HT_DEBUG */
677 		return;
678 	}
679 
680 	del_timer_sync(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
681 #ifdef CONFIG_MAC80211_HT_DEBUG
682 	printk(KERN_DEBUG "switched off addBA timer for tid %d \n", tid);
683 #endif /* CONFIG_MAC80211_HT_DEBUG */
684 	if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
685 			== WLAN_STATUS_SUCCESS) {
686 		u8 curstate = *state;
687 
688 		*state |= HT_ADDBA_RECEIVED_MSK;
689 
690 		if (*state != curstate && *state == HT_AGG_STATE_OPERATIONAL)
691 			ieee80211_agg_tx_operational(local, sta, tid);
692 
693 		sta->ampdu_mlme.addba_req_num[tid] = 0;
694 	} else {
695 		___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
696 	}
697 	spin_unlock_bh(&sta->lock);
698 }
699