xref: /linux/net/mac80211/agg-tx.c (revision c145211d1f9e2ef19e7b4c2b943f68366daa97af)
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 <linux/slab.h>
18 #include <net/mac80211.h>
19 #include "ieee80211_i.h"
20 #include "driver-ops.h"
21 #include "wme.h"
22 
23 /**
24  * DOC: TX aggregation
25  *
26  * Aggregation on the TX side requires setting the hardware flag
27  * %IEEE80211_HW_AMPDU_AGGREGATION as well as, if present, the @ampdu_queues
28  * hardware parameter to the number of hardware AMPDU queues. If there are no
29  * hardware queues then the driver will (currently) have to do all frame
30  * buffering.
31  *
32  * When TX aggregation is started by some subsystem (usually the rate control
33  * algorithm would be appropriate) by calling the
34  * ieee80211_start_tx_ba_session() function, the driver will be notified via
35  * its @ampdu_action function, with the %IEEE80211_AMPDU_TX_START action.
36  *
37  * In response to that, the driver is later required to call the
38  * ieee80211_start_tx_ba_cb() (or ieee80211_start_tx_ba_cb_irqsafe())
39  * function, which will start the aggregation session.
40  *
41  * Similarly, when the aggregation session is stopped by
42  * ieee80211_stop_tx_ba_session(), the driver's @ampdu_action function will
43  * be called with the action %IEEE80211_AMPDU_TX_STOP. In this case, the
44  * call must not fail, and the driver must later call ieee80211_stop_tx_ba_cb()
45  * (or ieee80211_stop_tx_ba_cb_irqsafe()).
46  */
47 
48 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
49 					 const u8 *da, u16 tid,
50 					 u8 dialog_token, u16 start_seq_num,
51 					 u16 agg_size, u16 timeout)
52 {
53 	struct ieee80211_local *local = sdata->local;
54 	struct sk_buff *skb;
55 	struct ieee80211_mgmt *mgmt;
56 	u16 capab;
57 
58 	skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
59 
60 	if (!skb) {
61 		printk(KERN_ERR "%s: failed to allocate buffer "
62 				"for addba request frame\n", sdata->name);
63 		return;
64 	}
65 	skb_reserve(skb, local->hw.extra_tx_headroom);
66 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
67 	memset(mgmt, 0, 24);
68 	memcpy(mgmt->da, da, ETH_ALEN);
69 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
70 	if (sdata->vif.type == NL80211_IFTYPE_AP ||
71 	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
72 		memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
73 	else if (sdata->vif.type == NL80211_IFTYPE_STATION)
74 		memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
75 
76 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
77 					  IEEE80211_STYPE_ACTION);
78 
79 	skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
80 
81 	mgmt->u.action.category = WLAN_CATEGORY_BACK;
82 	mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
83 
84 	mgmt->u.action.u.addba_req.dialog_token = dialog_token;
85 	capab = (u16)(1 << 1);		/* bit 1 aggregation policy */
86 	capab |= (u16)(tid << 2); 	/* bit 5:2 TID number */
87 	capab |= (u16)(agg_size << 6);	/* bit 15:6 max size of aggergation */
88 
89 	mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
90 
91 	mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
92 	mgmt->u.action.u.addba_req.start_seq_num =
93 					cpu_to_le16(start_seq_num << 4);
94 
95 	ieee80211_tx_skb(sdata, skb);
96 }
97 
98 void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u16 ssn)
99 {
100 	struct ieee80211_local *local = sdata->local;
101 	struct sk_buff *skb;
102 	struct ieee80211_bar *bar;
103 	u16 bar_control = 0;
104 
105 	skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
106 	if (!skb) {
107 		printk(KERN_ERR "%s: failed to allocate buffer for "
108 			"bar frame\n", sdata->name);
109 		return;
110 	}
111 	skb_reserve(skb, local->hw.extra_tx_headroom);
112 	bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
113 	memset(bar, 0, sizeof(*bar));
114 	bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
115 					 IEEE80211_STYPE_BACK_REQ);
116 	memcpy(bar->ra, ra, ETH_ALEN);
117 	memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
118 	bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
119 	bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
120 	bar_control |= (u16)(tid << 12);
121 	bar->control = cpu_to_le16(bar_control);
122 	bar->start_seq_num = cpu_to_le16(ssn);
123 
124 	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
125 	ieee80211_tx_skb(sdata, skb);
126 }
127 
128 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
129 				    enum ieee80211_back_parties initiator)
130 {
131 	struct ieee80211_local *local = sta->local;
132 	int ret;
133 	u8 *state;
134 
135 #ifdef CONFIG_MAC80211_HT_DEBUG
136 	printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
137 	       sta->sta.addr, tid);
138 #endif /* CONFIG_MAC80211_HT_DEBUG */
139 
140 	state = &sta->ampdu_mlme.tid_state_tx[tid];
141 
142 	if (*state == HT_AGG_STATE_OPERATIONAL)
143 		sta->ampdu_mlme.addba_req_num[tid] = 0;
144 
145 	*state = HT_AGG_STATE_REQ_STOP_BA_MSK |
146 		(initiator << HT_AGG_STATE_INITIATOR_SHIFT);
147 
148 	ret = drv_ampdu_action(local, sta->sdata,
149 			       IEEE80211_AMPDU_TX_STOP,
150 			       &sta->sta, tid, NULL);
151 
152 	/* HW shall not deny going back to legacy */
153 	if (WARN_ON(ret)) {
154 		/*
155 		 * We may have pending packets get stuck in this case...
156 		 * Not bothering with a workaround for now.
157 		 */
158 	}
159 
160 	return ret;
161 }
162 
163 /*
164  * After sending add Block Ack request we activated a timer until
165  * add Block Ack response will arrive from the recipient.
166  * If this timer expires sta_addba_resp_timer_expired will be executed.
167  */
168 static void sta_addba_resp_timer_expired(unsigned long data)
169 {
170 	/* not an elegant detour, but there is no choice as the timer passes
171 	 * only one argument, and both sta_info and TID are needed, so init
172 	 * flow in sta_info_create gives the TID as data, while the timer_to_id
173 	 * array gives the sta through container_of */
174 	u16 tid = *(u8 *)data;
175 	struct sta_info *sta = container_of((void *)data,
176 		struct sta_info, timer_to_tid[tid]);
177 	u8 *state;
178 
179 	state = &sta->ampdu_mlme.tid_state_tx[tid];
180 
181 	/* check if the TID waits for addBA response */
182 	spin_lock_bh(&sta->lock);
183 	if ((*state & (HT_ADDBA_REQUESTED_MSK | HT_ADDBA_RECEIVED_MSK |
184 		       HT_AGG_STATE_REQ_STOP_BA_MSK)) !=
185 						HT_ADDBA_REQUESTED_MSK) {
186 		spin_unlock_bh(&sta->lock);
187 #ifdef CONFIG_MAC80211_HT_DEBUG
188 		printk(KERN_DEBUG "timer expired on tid %d but we are not "
189 				"(or no longer) expecting addBA response there",
190 			tid);
191 #endif
192 		return;
193 	}
194 
195 #ifdef CONFIG_MAC80211_HT_DEBUG
196 	printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
197 #endif
198 
199 	___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
200 	spin_unlock_bh(&sta->lock);
201 }
202 
203 static inline int ieee80211_ac_from_tid(int tid)
204 {
205 	return ieee802_1d_to_ac[tid & 7];
206 }
207 
208 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
209 {
210 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
211 	struct ieee80211_sub_if_data *sdata = sta->sdata;
212 	struct ieee80211_local *local = sdata->local;
213 	u8 *state;
214 	int ret = 0;
215 	u16 start_seq_num;
216 
217 	if (WARN_ON(!local->ops->ampdu_action))
218 		return -EINVAL;
219 
220 	if ((tid >= STA_TID_NUM) ||
221 	    !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION))
222 		return -EINVAL;
223 
224 #ifdef CONFIG_MAC80211_HT_DEBUG
225 	printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
226 	       pubsta->addr, tid);
227 #endif /* CONFIG_MAC80211_HT_DEBUG */
228 
229 	/*
230 	 * The aggregation code is not prepared to handle
231 	 * anything but STA/AP due to the BSSID handling.
232 	 * IBSS could work in the code but isn't supported
233 	 * by drivers or the standard.
234 	 */
235 	if (sdata->vif.type != NL80211_IFTYPE_STATION &&
236 	    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
237 	    sdata->vif.type != NL80211_IFTYPE_AP)
238 		return -EINVAL;
239 
240 	if (test_sta_flags(sta, WLAN_STA_DISASSOC)) {
241 #ifdef CONFIG_MAC80211_HT_DEBUG
242 		printk(KERN_DEBUG "Disassociation is in progress. "
243 		       "Denying BA session request\n");
244 #endif
245 		return -EINVAL;
246 	}
247 
248 	if (test_sta_flags(sta, WLAN_STA_SUSPEND)) {
249 #ifdef CONFIG_MAC80211_HT_DEBUG
250 		printk(KERN_DEBUG "Suspend in progress. "
251 		       "Denying BA session request\n");
252 #endif
253 		return -EINVAL;
254 	}
255 
256 	spin_lock_bh(&sta->lock);
257 	spin_lock(&local->ampdu_lock);
258 
259 	/* we have tried too many times, receiver does not want A-MPDU */
260 	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
261 		ret = -EBUSY;
262 		goto err_unlock_sta;
263 	}
264 
265 	state = &sta->ampdu_mlme.tid_state_tx[tid];
266 	/* check if the TID is not in aggregation flow already */
267 	if (*state != HT_AGG_STATE_IDLE) {
268 #ifdef CONFIG_MAC80211_HT_DEBUG
269 		printk(KERN_DEBUG "BA request denied - session is not "
270 				 "idle on tid %u\n", tid);
271 #endif /* CONFIG_MAC80211_HT_DEBUG */
272 		ret = -EAGAIN;
273 		goto err_unlock_sta;
274 	}
275 
276 	/*
277 	 * While we're asking the driver about the aggregation,
278 	 * stop the AC queue so that we don't have to worry
279 	 * about frames that came in while we were doing that,
280 	 * which would require us to put them to the AC pending
281 	 * afterwards which just makes the code more complex.
282 	 */
283 	ieee80211_stop_queue_by_reason(
284 		&local->hw, ieee80211_ac_from_tid(tid),
285 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
286 
287 	/* prepare A-MPDU MLME for Tx aggregation */
288 	sta->ampdu_mlme.tid_tx[tid] =
289 			kmalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
290 	if (!sta->ampdu_mlme.tid_tx[tid]) {
291 #ifdef CONFIG_MAC80211_HT_DEBUG
292 		if (net_ratelimit())
293 			printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
294 					tid);
295 #endif
296 		ret = -ENOMEM;
297 		goto err_wake_queue;
298 	}
299 
300 	skb_queue_head_init(&sta->ampdu_mlme.tid_tx[tid]->pending);
301 
302 	/* Tx timer */
303 	sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.function =
304 			sta_addba_resp_timer_expired;
305 	sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.data =
306 			(unsigned long)&sta->timer_to_tid[tid];
307 	init_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
308 
309 	/* Ok, the Addba frame hasn't been sent yet, but if the driver calls the
310 	 * call back right away, it must see that the flow has begun */
311 	*state |= HT_ADDBA_REQUESTED_MSK;
312 
313 	start_seq_num = sta->tid_seq[tid] >> 4;
314 
315 	ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
316 			       pubsta, tid, &start_seq_num);
317 
318 	if (ret) {
319 #ifdef CONFIG_MAC80211_HT_DEBUG
320 		printk(KERN_DEBUG "BA request denied - HW unavailable for"
321 					" tid %d\n", tid);
322 #endif /* CONFIG_MAC80211_HT_DEBUG */
323 		*state = HT_AGG_STATE_IDLE;
324 		goto err_free;
325 	}
326 
327 	/* Driver vetoed or OKed, but we can take packets again now */
328 	ieee80211_wake_queue_by_reason(
329 		&local->hw, ieee80211_ac_from_tid(tid),
330 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
331 
332 	spin_unlock(&local->ampdu_lock);
333 	spin_unlock_bh(&sta->lock);
334 
335 	/* send an addBA request */
336 	sta->ampdu_mlme.dialog_token_allocator++;
337 	sta->ampdu_mlme.tid_tx[tid]->dialog_token =
338 			sta->ampdu_mlme.dialog_token_allocator;
339 	sta->ampdu_mlme.tid_tx[tid]->ssn = start_seq_num;
340 
341 	ieee80211_send_addba_request(sdata, pubsta->addr, tid,
342 			 sta->ampdu_mlme.tid_tx[tid]->dialog_token,
343 			 sta->ampdu_mlme.tid_tx[tid]->ssn,
344 			 0x40, 5000);
345 	sta->ampdu_mlme.addba_req_num[tid]++;
346 	/* activate the timer for the recipient's addBA response */
347 	sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
348 				jiffies + ADDBA_RESP_INTERVAL;
349 	add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
350 #ifdef CONFIG_MAC80211_HT_DEBUG
351 	printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
352 #endif
353 	return 0;
354 
355  err_free:
356 	kfree(sta->ampdu_mlme.tid_tx[tid]);
357 	sta->ampdu_mlme.tid_tx[tid] = NULL;
358  err_wake_queue:
359 	ieee80211_wake_queue_by_reason(
360 		&local->hw, ieee80211_ac_from_tid(tid),
361 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
362  err_unlock_sta:
363 	spin_unlock(&local->ampdu_lock);
364 	spin_unlock_bh(&sta->lock);
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 (!(sta->ampdu_mlme.tid_state_tx[tid] & HT_ADDBA_REQUESTED_MSK))
385 		return;
386 
387 	if (WARN(!sta->ampdu_mlme.tid_tx[tid],
388 		 "TID %d gone but expected when splicing aggregates from"
389 		 "the pending queue\n", tid))
390 		return;
391 
392 	if (!skb_queue_empty(&sta->ampdu_mlme.tid_tx[tid]->pending)) {
393 		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
394 		/* copy over remaining packets */
395 		skb_queue_splice_tail_init(
396 			&sta->ampdu_mlme.tid_tx[tid]->pending,
397 			&local->pending[queue]);
398 		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
399 	}
400 }
401 
402 static void ieee80211_agg_splice_finish(struct ieee80211_local *local,
403 					struct sta_info *sta, u16 tid)
404 {
405 	u16 queue = ieee80211_ac_from_tid(tid);
406 
407 	ieee80211_wake_queue_by_reason(
408 		&local->hw, queue,
409 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
410 }
411 
412 /* caller must hold sta->lock */
413 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
414 					 struct sta_info *sta, u16 tid)
415 {
416 #ifdef CONFIG_MAC80211_HT_DEBUG
417 	printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
418 #endif
419 
420 	spin_lock(&local->ampdu_lock);
421 	ieee80211_agg_splice_packets(local, sta, tid);
422 	/*
423 	 * NB: we rely on sta->lock being taken in the TX
424 	 * processing here when adding to the pending queue,
425 	 * otherwise we could only change the state of the
426 	 * session to OPERATIONAL _here_.
427 	 */
428 	ieee80211_agg_splice_finish(local, sta, tid);
429 	spin_unlock(&local->ampdu_lock);
430 
431 	drv_ampdu_action(local, sta->sdata,
432 			 IEEE80211_AMPDU_TX_OPERATIONAL,
433 			 &sta->sta, tid, NULL);
434 }
435 
436 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
437 {
438 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
439 	struct ieee80211_local *local = sdata->local;
440 	struct sta_info *sta;
441 	u8 *state;
442 
443 	if (tid >= STA_TID_NUM) {
444 #ifdef CONFIG_MAC80211_HT_DEBUG
445 		printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
446 				tid, STA_TID_NUM);
447 #endif
448 		return;
449 	}
450 
451 	rcu_read_lock();
452 	sta = sta_info_get(sdata, ra);
453 	if (!sta) {
454 		rcu_read_unlock();
455 #ifdef CONFIG_MAC80211_HT_DEBUG
456 		printk(KERN_DEBUG "Could not find station: %pM\n", ra);
457 #endif
458 		return;
459 	}
460 
461 	state = &sta->ampdu_mlme.tid_state_tx[tid];
462 	spin_lock_bh(&sta->lock);
463 
464 	if (WARN_ON(!(*state & HT_ADDBA_REQUESTED_MSK))) {
465 #ifdef CONFIG_MAC80211_HT_DEBUG
466 		printk(KERN_DEBUG "addBA was not requested yet, state is %d\n",
467 				*state);
468 #endif
469 		spin_unlock_bh(&sta->lock);
470 		rcu_read_unlock();
471 		return;
472 	}
473 
474 	if (WARN_ON(*state & HT_ADDBA_DRV_READY_MSK))
475 		goto out;
476 
477 	*state |= HT_ADDBA_DRV_READY_MSK;
478 
479 	if (*state == HT_AGG_STATE_OPERATIONAL)
480 		ieee80211_agg_tx_operational(local, sta, tid);
481 
482  out:
483 	spin_unlock_bh(&sta->lock);
484 	rcu_read_unlock();
485 }
486 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb);
487 
488 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
489 				      const u8 *ra, u16 tid)
490 {
491 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
492 	struct ieee80211_local *local = sdata->local;
493 	struct ieee80211_ra_tid *ra_tid;
494 	struct sk_buff *skb = dev_alloc_skb(0);
495 
496 	if (unlikely(!skb)) {
497 #ifdef CONFIG_MAC80211_HT_DEBUG
498 		if (net_ratelimit())
499 			printk(KERN_WARNING "%s: Not enough memory, "
500 			       "dropping start BA session", sdata->name);
501 #endif
502 		return;
503 	}
504 	ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
505 	memcpy(&ra_tid->ra, ra, ETH_ALEN);
506 	ra_tid->tid = tid;
507 	ra_tid->vif = vif;
508 
509 	skb->pkt_type = IEEE80211_ADDBA_MSG;
510 	skb_queue_tail(&local->skb_queue, skb);
511 	tasklet_schedule(&local->tasklet);
512 }
513 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
514 
515 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
516 				   enum ieee80211_back_parties initiator)
517 {
518 	u8 *state;
519 	int ret;
520 
521 	/* check if the TID is in aggregation */
522 	state = &sta->ampdu_mlme.tid_state_tx[tid];
523 	spin_lock_bh(&sta->lock);
524 
525 	if (*state != HT_AGG_STATE_OPERATIONAL) {
526 		ret = -ENOENT;
527 		goto unlock;
528 	}
529 
530 	ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator);
531 
532  unlock:
533 	spin_unlock_bh(&sta->lock);
534 	return ret;
535 }
536 
537 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
538 				 enum ieee80211_back_parties initiator)
539 {
540 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
541 	struct ieee80211_sub_if_data *sdata = sta->sdata;
542 	struct ieee80211_local *local = sdata->local;
543 
544 	if (!local->ops->ampdu_action)
545 		return -EINVAL;
546 
547 	if (tid >= STA_TID_NUM)
548 		return -EINVAL;
549 
550 	return __ieee80211_stop_tx_ba_session(sta, tid, initiator);
551 }
552 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
553 
554 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
555 {
556 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
557 	struct ieee80211_local *local = sdata->local;
558 	struct sta_info *sta;
559 	u8 *state;
560 
561 	if (tid >= STA_TID_NUM) {
562 #ifdef CONFIG_MAC80211_HT_DEBUG
563 		printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
564 				tid, STA_TID_NUM);
565 #endif
566 		return;
567 	}
568 
569 #ifdef CONFIG_MAC80211_HT_DEBUG
570 	printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
571 	       ra, tid);
572 #endif /* CONFIG_MAC80211_HT_DEBUG */
573 
574 	rcu_read_lock();
575 	sta = sta_info_get(sdata, ra);
576 	if (!sta) {
577 #ifdef CONFIG_MAC80211_HT_DEBUG
578 		printk(KERN_DEBUG "Could not find station: %pM\n", ra);
579 #endif
580 		rcu_read_unlock();
581 		return;
582 	}
583 	state = &sta->ampdu_mlme.tid_state_tx[tid];
584 
585 	/* NOTE: no need to use sta->lock in this state check, as
586 	 * ieee80211_stop_tx_ba_session will let only one stop call to
587 	 * pass through per sta/tid
588 	 */
589 	if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) {
590 #ifdef CONFIG_MAC80211_HT_DEBUG
591 		printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
592 #endif
593 		rcu_read_unlock();
594 		return;
595 	}
596 
597 	if (*state & HT_AGG_STATE_INITIATOR_MSK)
598 		ieee80211_send_delba(sta->sdata, ra, tid,
599 			WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
600 
601 	spin_lock_bh(&sta->lock);
602 	spin_lock(&local->ampdu_lock);
603 
604 	ieee80211_agg_splice_packets(local, sta, tid);
605 
606 	*state = HT_AGG_STATE_IDLE;
607 	/* from now on packets are no longer put onto sta->pending */
608 	kfree(sta->ampdu_mlme.tid_tx[tid]);
609 	sta->ampdu_mlme.tid_tx[tid] = NULL;
610 
611 	ieee80211_agg_splice_finish(local, sta, tid);
612 
613 	spin_unlock(&local->ampdu_lock);
614 	spin_unlock_bh(&sta->lock);
615 
616 	rcu_read_unlock();
617 }
618 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb);
619 
620 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
621 				     const u8 *ra, u16 tid)
622 {
623 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
624 	struct ieee80211_local *local = sdata->local;
625 	struct ieee80211_ra_tid *ra_tid;
626 	struct sk_buff *skb = dev_alloc_skb(0);
627 
628 	if (unlikely(!skb)) {
629 #ifdef CONFIG_MAC80211_HT_DEBUG
630 		if (net_ratelimit())
631 			printk(KERN_WARNING "%s: Not enough memory, "
632 			       "dropping stop BA session", sdata->name);
633 #endif
634 		return;
635 	}
636 	ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
637 	memcpy(&ra_tid->ra, ra, ETH_ALEN);
638 	ra_tid->tid = tid;
639 	ra_tid->vif = vif;
640 
641 	skb->pkt_type = IEEE80211_DELBA_MSG;
642 	skb_queue_tail(&local->skb_queue, skb);
643 	tasklet_schedule(&local->tasklet);
644 }
645 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
646 
647 
648 void ieee80211_process_addba_resp(struct ieee80211_local *local,
649 				  struct sta_info *sta,
650 				  struct ieee80211_mgmt *mgmt,
651 				  size_t len)
652 {
653 	u16 capab, tid;
654 	u8 *state;
655 
656 	capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
657 	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
658 
659 	state = &sta->ampdu_mlme.tid_state_tx[tid];
660 
661 	spin_lock_bh(&sta->lock);
662 
663 	if (!(*state & HT_ADDBA_REQUESTED_MSK))
664 		goto out;
665 
666 	if (mgmt->u.action.u.addba_resp.dialog_token !=
667 		sta->ampdu_mlme.tid_tx[tid]->dialog_token) {
668 #ifdef CONFIG_MAC80211_HT_DEBUG
669 		printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
670 #endif /* CONFIG_MAC80211_HT_DEBUG */
671 		goto out;
672 	}
673 
674 	del_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
675 
676 #ifdef CONFIG_MAC80211_HT_DEBUG
677 	printk(KERN_DEBUG "switched off addBA timer for tid %d \n", tid);
678 #endif /* CONFIG_MAC80211_HT_DEBUG */
679 
680 	if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
681 			== WLAN_STATUS_SUCCESS) {
682 		u8 curstate = *state;
683 
684 		*state |= HT_ADDBA_RECEIVED_MSK;
685 
686 		if (*state != curstate && *state == HT_AGG_STATE_OPERATIONAL)
687 			ieee80211_agg_tx_operational(local, sta, tid);
688 
689 		sta->ampdu_mlme.addba_req_num[tid] = 0;
690 	} else {
691 		___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
692 	}
693 
694  out:
695 	spin_unlock_bh(&sta->lock);
696 }
697