xref: /openbmc/linux/net/mac80211/agg-tx.c (revision 98ddec80)
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 2007-2010, Intel Corporation
10  * Copyright(c) 2015-2017 Intel Deutschland GmbH
11  * Copyright (C) 2018 Intel Corporation
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License version 2 as
15  * published by the Free Software Foundation.
16  */
17 
18 #include <linux/ieee80211.h>
19 #include <linux/slab.h>
20 #include <linux/export.h>
21 #include <net/mac80211.h>
22 #include "ieee80211_i.h"
23 #include "driver-ops.h"
24 #include "wme.h"
25 
26 /**
27  * DOC: TX A-MPDU aggregation
28  *
29  * Aggregation on the TX side requires setting the hardware flag
30  * %IEEE80211_HW_AMPDU_AGGREGATION. The driver will then be handed
31  * packets with a flag indicating A-MPDU aggregation. The driver
32  * or device is responsible for actually aggregating the frames,
33  * as well as deciding how many and which to aggregate.
34  *
35  * When TX aggregation is started by some subsystem (usually the rate
36  * control algorithm would be appropriate) by calling the
37  * ieee80211_start_tx_ba_session() function, the driver will be
38  * notified via its @ampdu_action function, with the
39  * %IEEE80211_AMPDU_TX_START action.
40  *
41  * In response to that, the driver is later required to call the
42  * ieee80211_start_tx_ba_cb_irqsafe() function, which will really
43  * start the aggregation session after the peer has also responded.
44  * If the peer responds negatively, the session will be stopped
45  * again right away. Note that it is possible for the aggregation
46  * session to be stopped before the driver has indicated that it
47  * is done setting it up, in which case it must not indicate the
48  * setup completion.
49  *
50  * Also note that, since we also need to wait for a response from
51  * the peer, the driver is notified of the completion of the
52  * handshake by the %IEEE80211_AMPDU_TX_OPERATIONAL action to the
53  * @ampdu_action callback.
54  *
55  * Similarly, when the aggregation session is stopped by the peer
56  * or something calling ieee80211_stop_tx_ba_session(), the driver's
57  * @ampdu_action function will be called with the action
58  * %IEEE80211_AMPDU_TX_STOP. In this case, the call must not fail,
59  * and the driver must later call ieee80211_stop_tx_ba_cb_irqsafe().
60  * Note that the sta can get destroyed before the BA tear down is
61  * complete.
62  */
63 
64 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
65 					 const u8 *da, u16 tid,
66 					 u8 dialog_token, u16 start_seq_num,
67 					 u16 agg_size, u16 timeout)
68 {
69 	struct ieee80211_local *local = sdata->local;
70 	struct sk_buff *skb;
71 	struct ieee80211_mgmt *mgmt;
72 	u16 capab;
73 
74 	skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
75 
76 	if (!skb)
77 		return;
78 
79 	skb_reserve(skb, local->hw.extra_tx_headroom);
80 	mgmt = skb_put_zero(skb, 24);
81 	memcpy(mgmt->da, da, ETH_ALEN);
82 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
83 	if (sdata->vif.type == NL80211_IFTYPE_AP ||
84 	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
85 	    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
86 		memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
87 	else if (sdata->vif.type == NL80211_IFTYPE_STATION)
88 		memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
89 	else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
90 		memcpy(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN);
91 
92 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
93 					  IEEE80211_STYPE_ACTION);
94 
95 	skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
96 
97 	mgmt->u.action.category = WLAN_CATEGORY_BACK;
98 	mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
99 
100 	mgmt->u.action.u.addba_req.dialog_token = dialog_token;
101 	capab = (u16)(1 << 0);		/* bit 0 A-MSDU support */
102 	capab |= (u16)(1 << 1);		/* bit 1 aggregation policy */
103 	capab |= (u16)(tid << 2); 	/* bit 5:2 TID number */
104 	capab |= (u16)(agg_size << 6);	/* bit 15:6 max size of aggergation */
105 
106 	mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
107 
108 	mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
109 	mgmt->u.action.u.addba_req.start_seq_num =
110 					cpu_to_le16(start_seq_num << 4);
111 
112 	ieee80211_tx_skb(sdata, skb);
113 }
114 
115 void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
116 {
117 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
118 	struct ieee80211_local *local = sdata->local;
119 	struct sk_buff *skb;
120 	struct ieee80211_bar *bar;
121 	u16 bar_control = 0;
122 
123 	skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
124 	if (!skb)
125 		return;
126 
127 	skb_reserve(skb, local->hw.extra_tx_headroom);
128 	bar = skb_put_zero(skb, sizeof(*bar));
129 	bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
130 					 IEEE80211_STYPE_BACK_REQ);
131 	memcpy(bar->ra, ra, ETH_ALEN);
132 	memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
133 	bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
134 	bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
135 	bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
136 	bar->control = cpu_to_le16(bar_control);
137 	bar->start_seq_num = cpu_to_le16(ssn);
138 
139 	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
140 					IEEE80211_TX_CTL_REQ_TX_STATUS;
141 	ieee80211_tx_skb_tid(sdata, skb, tid);
142 }
143 EXPORT_SYMBOL(ieee80211_send_bar);
144 
145 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
146 			     struct tid_ampdu_tx *tid_tx)
147 {
148 	lockdep_assert_held(&sta->ampdu_mlme.mtx);
149 	lockdep_assert_held(&sta->lock);
150 	rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
151 }
152 
153 /*
154  * When multiple aggregation sessions on multiple stations
155  * are being created/destroyed simultaneously, we need to
156  * refcount the global queue stop caused by that in order
157  * to not get into a situation where one of the aggregation
158  * setup or teardown re-enables queues before the other is
159  * ready to handle that.
160  *
161  * These two functions take care of this issue by keeping
162  * a global "agg_queue_stop" refcount.
163  */
164 static void __acquires(agg_queue)
165 ieee80211_stop_queue_agg(struct ieee80211_sub_if_data *sdata, int tid)
166 {
167 	int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
168 
169 	/* we do refcounting here, so don't use the queue reason refcounting */
170 
171 	if (atomic_inc_return(&sdata->local->agg_queue_stop[queue]) == 1)
172 		ieee80211_stop_queue_by_reason(
173 			&sdata->local->hw, queue,
174 			IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
175 			false);
176 	__acquire(agg_queue);
177 }
178 
179 static void __releases(agg_queue)
180 ieee80211_wake_queue_agg(struct ieee80211_sub_if_data *sdata, int tid)
181 {
182 	int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
183 
184 	if (atomic_dec_return(&sdata->local->agg_queue_stop[queue]) == 0)
185 		ieee80211_wake_queue_by_reason(
186 			&sdata->local->hw, queue,
187 			IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
188 			false);
189 	__release(agg_queue);
190 }
191 
192 static void
193 ieee80211_agg_stop_txq(struct sta_info *sta, int tid)
194 {
195 	struct ieee80211_txq *txq = sta->sta.txq[tid];
196 	struct ieee80211_sub_if_data *sdata;
197 	struct fq *fq;
198 	struct txq_info *txqi;
199 
200 	if (!txq)
201 		return;
202 
203 	txqi = to_txq_info(txq);
204 	sdata = vif_to_sdata(txq->vif);
205 	fq = &sdata->local->fq;
206 
207 	/* Lock here to protect against further seqno updates on dequeue */
208 	spin_lock_bh(&fq->lock);
209 	set_bit(IEEE80211_TXQ_STOP, &txqi->flags);
210 	spin_unlock_bh(&fq->lock);
211 }
212 
213 static void
214 ieee80211_agg_start_txq(struct sta_info *sta, int tid, bool enable)
215 {
216 	struct ieee80211_txq *txq = sta->sta.txq[tid];
217 	struct txq_info *txqi;
218 
219 	if (!txq)
220 		return;
221 
222 	txqi = to_txq_info(txq);
223 
224 	if (enable)
225 		set_bit(IEEE80211_TXQ_AMPDU, &txqi->flags);
226 	else
227 		clear_bit(IEEE80211_TXQ_AMPDU, &txqi->flags);
228 
229 	clear_bit(IEEE80211_TXQ_STOP, &txqi->flags);
230 	local_bh_disable();
231 	rcu_read_lock();
232 	drv_wake_tx_queue(sta->sdata->local, txqi);
233 	rcu_read_unlock();
234 	local_bh_enable();
235 }
236 
237 /*
238  * splice packets from the STA's pending to the local pending,
239  * requires a call to ieee80211_agg_splice_finish later
240  */
241 static void __acquires(agg_queue)
242 ieee80211_agg_splice_packets(struct ieee80211_sub_if_data *sdata,
243 			     struct tid_ampdu_tx *tid_tx, u16 tid)
244 {
245 	struct ieee80211_local *local = sdata->local;
246 	int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
247 	unsigned long flags;
248 
249 	ieee80211_stop_queue_agg(sdata, tid);
250 
251 	if (WARN(!tid_tx,
252 		 "TID %d gone but expected when splicing aggregates from the pending queue\n",
253 		 tid))
254 		return;
255 
256 	if (!skb_queue_empty(&tid_tx->pending)) {
257 		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
258 		/* copy over remaining packets */
259 		skb_queue_splice_tail_init(&tid_tx->pending,
260 					   &local->pending[queue]);
261 		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
262 	}
263 }
264 
265 static void __releases(agg_queue)
266 ieee80211_agg_splice_finish(struct ieee80211_sub_if_data *sdata, u16 tid)
267 {
268 	ieee80211_wake_queue_agg(sdata, tid);
269 }
270 
271 static void ieee80211_remove_tid_tx(struct sta_info *sta, int tid)
272 {
273 	struct tid_ampdu_tx *tid_tx;
274 
275 	lockdep_assert_held(&sta->ampdu_mlme.mtx);
276 	lockdep_assert_held(&sta->lock);
277 
278 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
279 
280 	/*
281 	 * When we get here, the TX path will not be lockless any more wrt.
282 	 * aggregation, since the OPERATIONAL bit has long been cleared.
283 	 * Thus it will block on getting the lock, if it occurs. So if we
284 	 * stop the queue now, we will not get any more packets, and any
285 	 * that might be being processed will wait for us here, thereby
286 	 * guaranteeing that no packets go to the tid_tx pending queue any
287 	 * more.
288 	 */
289 
290 	ieee80211_agg_splice_packets(sta->sdata, tid_tx, tid);
291 
292 	/* future packets must not find the tid_tx struct any more */
293 	ieee80211_assign_tid_tx(sta, tid, NULL);
294 
295 	ieee80211_agg_splice_finish(sta->sdata, tid);
296 	ieee80211_agg_start_txq(sta, tid, false);
297 
298 	kfree_rcu(tid_tx, rcu_head);
299 }
300 
301 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
302 				    enum ieee80211_agg_stop_reason reason)
303 {
304 	struct ieee80211_local *local = sta->local;
305 	struct tid_ampdu_tx *tid_tx;
306 	struct ieee80211_ampdu_params params = {
307 		.sta = &sta->sta,
308 		.tid = tid,
309 		.buf_size = 0,
310 		.amsdu = false,
311 		.timeout = 0,
312 		.ssn = 0,
313 	};
314 	int ret;
315 
316 	lockdep_assert_held(&sta->ampdu_mlme.mtx);
317 
318 	switch (reason) {
319 	case AGG_STOP_DECLINED:
320 	case AGG_STOP_LOCAL_REQUEST:
321 	case AGG_STOP_PEER_REQUEST:
322 		params.action = IEEE80211_AMPDU_TX_STOP_CONT;
323 		break;
324 	case AGG_STOP_DESTROY_STA:
325 		params.action = IEEE80211_AMPDU_TX_STOP_FLUSH;
326 		break;
327 	default:
328 		WARN_ON_ONCE(1);
329 		return -EINVAL;
330 	}
331 
332 	spin_lock_bh(&sta->lock);
333 
334 	/* free struct pending for start, if present */
335 	tid_tx = sta->ampdu_mlme.tid_start_tx[tid];
336 	kfree(tid_tx);
337 	sta->ampdu_mlme.tid_start_tx[tid] = NULL;
338 
339 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
340 	if (!tid_tx) {
341 		spin_unlock_bh(&sta->lock);
342 		return -ENOENT;
343 	}
344 
345 	/*
346 	 * if we're already stopping ignore any new requests to stop
347 	 * unless we're destroying it in which case notify the driver
348 	 */
349 	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
350 		spin_unlock_bh(&sta->lock);
351 		if (reason != AGG_STOP_DESTROY_STA)
352 			return -EALREADY;
353 		params.action = IEEE80211_AMPDU_TX_STOP_FLUSH_CONT;
354 		ret = drv_ampdu_action(local, sta->sdata, &params);
355 		WARN_ON_ONCE(ret);
356 		return 0;
357 	}
358 
359 	if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
360 		/* not even started yet! */
361 		ieee80211_assign_tid_tx(sta, tid, NULL);
362 		spin_unlock_bh(&sta->lock);
363 		kfree_rcu(tid_tx, rcu_head);
364 		return 0;
365 	}
366 
367 	set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
368 
369 	spin_unlock_bh(&sta->lock);
370 
371 	ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
372 	       sta->sta.addr, tid);
373 
374 	del_timer_sync(&tid_tx->addba_resp_timer);
375 	del_timer_sync(&tid_tx->session_timer);
376 
377 	/*
378 	 * After this packets are no longer handed right through
379 	 * to the driver but are put onto tid_tx->pending instead,
380 	 * with locking to ensure proper access.
381 	 */
382 	clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
383 
384 	/*
385 	 * There might be a few packets being processed right now (on
386 	 * another CPU) that have already gotten past the aggregation
387 	 * check when it was still OPERATIONAL and consequently have
388 	 * IEEE80211_TX_CTL_AMPDU set. In that case, this code might
389 	 * call into the driver at the same time or even before the
390 	 * TX paths calls into it, which could confuse the driver.
391 	 *
392 	 * Wait for all currently running TX paths to finish before
393 	 * telling the driver. New packets will not go through since
394 	 * the aggregation session is no longer OPERATIONAL.
395 	 */
396 	if (!local->in_reconfig)
397 		synchronize_net();
398 
399 	tid_tx->stop_initiator = reason == AGG_STOP_PEER_REQUEST ?
400 					WLAN_BACK_RECIPIENT :
401 					WLAN_BACK_INITIATOR;
402 	tid_tx->tx_stop = reason == AGG_STOP_LOCAL_REQUEST;
403 
404 	ret = drv_ampdu_action(local, sta->sdata, &params);
405 
406 	/* HW shall not deny going back to legacy */
407 	if (WARN_ON(ret)) {
408 		/*
409 		 * We may have pending packets get stuck in this case...
410 		 * Not bothering with a workaround for now.
411 		 */
412 	}
413 
414 	/*
415 	 * In the case of AGG_STOP_DESTROY_STA, the driver won't
416 	 * necessarily call ieee80211_stop_tx_ba_cb(), so this may
417 	 * seem like we can leave the tid_tx data pending forever.
418 	 * This is true, in a way, but "forever" is only until the
419 	 * station struct is actually destroyed. In the meantime,
420 	 * leaving it around ensures that we don't transmit packets
421 	 * to the driver on this TID which might confuse it.
422 	 */
423 
424 	return 0;
425 }
426 
427 /*
428  * After sending add Block Ack request we activated a timer until
429  * add Block Ack response will arrive from the recipient.
430  * If this timer expires sta_addba_resp_timer_expired will be executed.
431  */
432 static void sta_addba_resp_timer_expired(struct timer_list *t)
433 {
434 	struct tid_ampdu_tx *tid_tx = from_timer(tid_tx, t, addba_resp_timer);
435 	struct sta_info *sta = tid_tx->sta;
436 	u8 tid = tid_tx->tid;
437 
438 	/* check if the TID waits for addBA response */
439 	if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
440 		ht_dbg(sta->sdata,
441 		       "timer expired on %pM tid %d not expecting addBA response\n",
442 		       sta->sta.addr, tid);
443 		return;
444 	}
445 
446 	ht_dbg(sta->sdata, "addBA response timer expired on %pM tid %d\n",
447 	       sta->sta.addr, tid);
448 
449 	ieee80211_stop_tx_ba_session(&sta->sta, tid);
450 }
451 
452 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
453 {
454 	struct tid_ampdu_tx *tid_tx;
455 	struct ieee80211_local *local = sta->local;
456 	struct ieee80211_sub_if_data *sdata = sta->sdata;
457 	struct ieee80211_ampdu_params params = {
458 		.sta = &sta->sta,
459 		.action = IEEE80211_AMPDU_TX_START,
460 		.tid = tid,
461 		.buf_size = 0,
462 		.amsdu = false,
463 		.timeout = 0,
464 	};
465 	int ret;
466 
467 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
468 
469 	/*
470 	 * Start queuing up packets for this aggregation session.
471 	 * We're going to release them once the driver is OK with
472 	 * that.
473 	 */
474 	clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
475 
476 	ieee80211_agg_stop_txq(sta, tid);
477 
478 	/*
479 	 * Make sure no packets are being processed. This ensures that
480 	 * we have a valid starting sequence number and that in-flight
481 	 * packets have been flushed out and no packets for this TID
482 	 * will go into the driver during the ampdu_action call.
483 	 */
484 	synchronize_net();
485 
486 	params.ssn = sta->tid_seq[tid] >> 4;
487 	ret = drv_ampdu_action(local, sdata, &params);
488 	if (ret) {
489 		ht_dbg(sdata,
490 		       "BA request denied - HW unavailable for %pM tid %d\n",
491 		       sta->sta.addr, tid);
492 		spin_lock_bh(&sta->lock);
493 		ieee80211_agg_splice_packets(sdata, tid_tx, tid);
494 		ieee80211_assign_tid_tx(sta, tid, NULL);
495 		ieee80211_agg_splice_finish(sdata, tid);
496 		spin_unlock_bh(&sta->lock);
497 
498 		ieee80211_agg_start_txq(sta, tid, false);
499 
500 		kfree_rcu(tid_tx, rcu_head);
501 		return;
502 	}
503 
504 	/* activate the timer for the recipient's addBA response */
505 	mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
506 	ht_dbg(sdata, "activated addBA response timer on %pM tid %d\n",
507 	       sta->sta.addr, tid);
508 
509 	spin_lock_bh(&sta->lock);
510 	sta->ampdu_mlme.last_addba_req_time[tid] = jiffies;
511 	sta->ampdu_mlme.addba_req_num[tid]++;
512 	spin_unlock_bh(&sta->lock);
513 
514 	/* send AddBA request */
515 	ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
516 				     tid_tx->dialog_token, params.ssn,
517 				     IEEE80211_MAX_AMPDU_BUF,
518 				     tid_tx->timeout);
519 }
520 
521 /*
522  * After accepting the AddBA Response we activated a timer,
523  * resetting it after each frame that we send.
524  */
525 static void sta_tx_agg_session_timer_expired(struct timer_list *t)
526 {
527 	struct tid_ampdu_tx *tid_tx = from_timer(tid_tx, t, session_timer);
528 	struct sta_info *sta = tid_tx->sta;
529 	u8 tid = tid_tx->tid;
530 	unsigned long timeout;
531 
532 	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
533 		return;
534 	}
535 
536 	timeout = tid_tx->last_tx + TU_TO_JIFFIES(tid_tx->timeout);
537 	if (time_is_after_jiffies(timeout)) {
538 		mod_timer(&tid_tx->session_timer, timeout);
539 		return;
540 	}
541 
542 	ht_dbg(sta->sdata, "tx session timer expired on %pM tid %d\n",
543 	       sta->sta.addr, tid);
544 
545 	ieee80211_stop_tx_ba_session(&sta->sta, tid);
546 }
547 
548 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
549 				  u16 timeout)
550 {
551 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
552 	struct ieee80211_sub_if_data *sdata = sta->sdata;
553 	struct ieee80211_local *local = sdata->local;
554 	struct tid_ampdu_tx *tid_tx;
555 	int ret = 0;
556 
557 	trace_api_start_tx_ba_session(pubsta, tid);
558 
559 	if (WARN(sta->reserved_tid == tid,
560 		 "Requested to start BA session on reserved tid=%d", tid))
561 		return -EINVAL;
562 
563 	if (!pubsta->ht_cap.ht_supported)
564 		return -EINVAL;
565 
566 	if (WARN_ON_ONCE(!local->ops->ampdu_action))
567 		return -EINVAL;
568 
569 	if ((tid >= IEEE80211_NUM_TIDS) ||
570 	    !ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION) ||
571 	    ieee80211_hw_check(&local->hw, TX_AMPDU_SETUP_IN_HW))
572 		return -EINVAL;
573 
574 	if (WARN_ON(tid >= IEEE80211_FIRST_TSPEC_TSID))
575 		return -EINVAL;
576 
577 	ht_dbg(sdata, "Open BA session requested for %pM tid %u\n",
578 	       pubsta->addr, tid);
579 
580 	if (sdata->vif.type != NL80211_IFTYPE_STATION &&
581 	    sdata->vif.type != NL80211_IFTYPE_MESH_POINT &&
582 	    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
583 	    sdata->vif.type != NL80211_IFTYPE_AP &&
584 	    sdata->vif.type != NL80211_IFTYPE_ADHOC)
585 		return -EINVAL;
586 
587 	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
588 		ht_dbg(sdata,
589 		       "BA sessions blocked - Denying BA session request %pM tid %d\n",
590 		       sta->sta.addr, tid);
591 		return -EINVAL;
592 	}
593 
594 	/*
595 	 * 802.11n-2009 11.5.1.1: If the initiating STA is an HT STA, is a
596 	 * member of an IBSS, and has no other existing Block Ack agreement
597 	 * with the recipient STA, then the initiating STA shall transmit a
598 	 * Probe Request frame to the recipient STA and shall not transmit an
599 	 * ADDBA Request frame unless it receives a Probe Response frame
600 	 * from the recipient within dot11ADDBAFailureTimeout.
601 	 *
602 	 * The probe request mechanism for ADDBA is currently not implemented,
603 	 * but we only build up Block Ack session with HT STAs. This information
604 	 * is set when we receive a bss info from a probe response or a beacon.
605 	 */
606 	if (sta->sdata->vif.type == NL80211_IFTYPE_ADHOC &&
607 	    !sta->sta.ht_cap.ht_supported) {
608 		ht_dbg(sdata,
609 		       "BA request denied - IBSS STA %pM does not advertise HT support\n",
610 		       pubsta->addr);
611 		return -EINVAL;
612 	}
613 
614 	spin_lock_bh(&sta->lock);
615 
616 	/* we have tried too many times, receiver does not want A-MPDU */
617 	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
618 		ret = -EBUSY;
619 		goto err_unlock_sta;
620 	}
621 
622 	/*
623 	 * if we have tried more than HT_AGG_BURST_RETRIES times we
624 	 * will spread our requests in time to avoid stalling connection
625 	 * for too long
626 	 */
627 	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_BURST_RETRIES &&
628 	    time_before(jiffies, sta->ampdu_mlme.last_addba_req_time[tid] +
629 			HT_AGG_RETRIES_PERIOD)) {
630 		ht_dbg(sdata,
631 		       "BA request denied - %d failed requests on %pM tid %u\n",
632 		       sta->ampdu_mlme.addba_req_num[tid], sta->sta.addr, tid);
633 		ret = -EBUSY;
634 		goto err_unlock_sta;
635 	}
636 
637 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
638 	/* check if the TID is not in aggregation flow already */
639 	if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
640 		ht_dbg(sdata,
641 		       "BA request denied - session is not idle on %pM tid %u\n",
642 		       sta->sta.addr, tid);
643 		ret = -EAGAIN;
644 		goto err_unlock_sta;
645 	}
646 
647 	/* prepare A-MPDU MLME for Tx aggregation */
648 	tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
649 	if (!tid_tx) {
650 		ret = -ENOMEM;
651 		goto err_unlock_sta;
652 	}
653 
654 	skb_queue_head_init(&tid_tx->pending);
655 	__set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
656 
657 	tid_tx->timeout = timeout;
658 	tid_tx->sta = sta;
659 	tid_tx->tid = tid;
660 
661 	/* response timer */
662 	timer_setup(&tid_tx->addba_resp_timer, sta_addba_resp_timer_expired, 0);
663 
664 	/* tx timer */
665 	timer_setup(&tid_tx->session_timer,
666 		    sta_tx_agg_session_timer_expired, TIMER_DEFERRABLE);
667 
668 	/* assign a dialog token */
669 	sta->ampdu_mlme.dialog_token_allocator++;
670 	tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
671 
672 	/*
673 	 * Finally, assign it to the start array; the work item will
674 	 * collect it and move it to the normal array.
675 	 */
676 	sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
677 
678 	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
679 
680 	/* this flow continues off the work */
681  err_unlock_sta:
682 	spin_unlock_bh(&sta->lock);
683 	return ret;
684 }
685 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
686 
687 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
688 					 struct sta_info *sta, u16 tid)
689 {
690 	struct tid_ampdu_tx *tid_tx;
691 	struct ieee80211_ampdu_params params = {
692 		.sta = &sta->sta,
693 		.action = IEEE80211_AMPDU_TX_OPERATIONAL,
694 		.tid = tid,
695 		.timeout = 0,
696 		.ssn = 0,
697 	};
698 
699 	lockdep_assert_held(&sta->ampdu_mlme.mtx);
700 
701 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
702 	params.buf_size = tid_tx->buf_size;
703 	params.amsdu = tid_tx->amsdu;
704 
705 	ht_dbg(sta->sdata, "Aggregation is on for %pM tid %d\n",
706 	       sta->sta.addr, tid);
707 
708 	drv_ampdu_action(local, sta->sdata, &params);
709 
710 	/*
711 	 * synchronize with TX path, while splicing the TX path
712 	 * should block so it won't put more packets onto pending.
713 	 */
714 	spin_lock_bh(&sta->lock);
715 
716 	ieee80211_agg_splice_packets(sta->sdata, tid_tx, tid);
717 	/*
718 	 * Now mark as operational. This will be visible
719 	 * in the TX path, and lets it go lock-free in
720 	 * the common case.
721 	 */
722 	set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
723 	ieee80211_agg_splice_finish(sta->sdata, tid);
724 
725 	spin_unlock_bh(&sta->lock);
726 
727 	ieee80211_agg_start_txq(sta, tid, true);
728 }
729 
730 void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
731 			      struct tid_ampdu_tx *tid_tx)
732 {
733 	struct ieee80211_sub_if_data *sdata = sta->sdata;
734 	struct ieee80211_local *local = sdata->local;
735 
736 	if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
737 		return;
738 
739 	if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
740 		ieee80211_agg_tx_operational(local, sta, tid);
741 }
742 
743 static struct tid_ampdu_tx *
744 ieee80211_lookup_tid_tx(struct ieee80211_sub_if_data *sdata,
745 			const u8 *ra, u16 tid, struct sta_info **sta)
746 {
747 	struct tid_ampdu_tx *tid_tx;
748 
749 	if (tid >= IEEE80211_NUM_TIDS) {
750 		ht_dbg(sdata, "Bad TID value: tid = %d (>= %d)\n",
751 		       tid, IEEE80211_NUM_TIDS);
752 		return NULL;
753 	}
754 
755 	*sta = sta_info_get_bss(sdata, ra);
756 	if (!*sta) {
757 		ht_dbg(sdata, "Could not find station: %pM\n", ra);
758 		return NULL;
759 	}
760 
761 	tid_tx = rcu_dereference((*sta)->ampdu_mlme.tid_tx[tid]);
762 
763 	if (WARN_ON(!tid_tx))
764 		ht_dbg(sdata, "addBA was not requested!\n");
765 
766 	return tid_tx;
767 }
768 
769 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
770 				      const u8 *ra, u16 tid)
771 {
772 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
773 	struct ieee80211_local *local = sdata->local;
774 	struct sta_info *sta;
775 	struct tid_ampdu_tx *tid_tx;
776 
777 	trace_api_start_tx_ba_cb(sdata, ra, tid);
778 
779 	rcu_read_lock();
780 	tid_tx = ieee80211_lookup_tid_tx(sdata, ra, tid, &sta);
781 	if (!tid_tx)
782 		goto out;
783 
784 	set_bit(HT_AGG_STATE_START_CB, &tid_tx->state);
785 	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
786  out:
787 	rcu_read_unlock();
788 }
789 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
790 
791 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
792 				   enum ieee80211_agg_stop_reason reason)
793 {
794 	int ret;
795 
796 	mutex_lock(&sta->ampdu_mlme.mtx);
797 
798 	ret = ___ieee80211_stop_tx_ba_session(sta, tid, reason);
799 
800 	mutex_unlock(&sta->ampdu_mlme.mtx);
801 
802 	return ret;
803 }
804 
805 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
806 {
807 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
808 	struct ieee80211_sub_if_data *sdata = sta->sdata;
809 	struct ieee80211_local *local = sdata->local;
810 	struct tid_ampdu_tx *tid_tx;
811 	int ret = 0;
812 
813 	trace_api_stop_tx_ba_session(pubsta, tid);
814 
815 	if (!local->ops->ampdu_action)
816 		return -EINVAL;
817 
818 	if (tid >= IEEE80211_NUM_TIDS)
819 		return -EINVAL;
820 
821 	spin_lock_bh(&sta->lock);
822 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
823 
824 	if (!tid_tx) {
825 		ret = -ENOENT;
826 		goto unlock;
827 	}
828 
829 	WARN(sta->reserved_tid == tid,
830 	     "Requested to stop BA session on reserved tid=%d", tid);
831 
832 	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
833 		/* already in progress stopping it */
834 		ret = 0;
835 		goto unlock;
836 	}
837 
838 	set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
839 	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
840 
841  unlock:
842 	spin_unlock_bh(&sta->lock);
843 	return ret;
844 }
845 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
846 
847 void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
848 			     struct tid_ampdu_tx *tid_tx)
849 {
850 	struct ieee80211_sub_if_data *sdata = sta->sdata;
851 	bool send_delba = false;
852 
853 	ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
854 	       sta->sta.addr, tid);
855 
856 	spin_lock_bh(&sta->lock);
857 
858 	if (!test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
859 		ht_dbg(sdata,
860 		       "unexpected callback to A-MPDU stop for %pM tid %d\n",
861 		       sta->sta.addr, tid);
862 		goto unlock_sta;
863 	}
864 
865 	if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
866 		send_delba = true;
867 
868 	ieee80211_remove_tid_tx(sta, tid);
869 
870  unlock_sta:
871 	spin_unlock_bh(&sta->lock);
872 
873 	if (send_delba)
874 		ieee80211_send_delba(sdata, sta->sta.addr, tid,
875 			WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
876 }
877 
878 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
879 				     const u8 *ra, u16 tid)
880 {
881 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
882 	struct ieee80211_local *local = sdata->local;
883 	struct sta_info *sta;
884 	struct tid_ampdu_tx *tid_tx;
885 
886 	trace_api_stop_tx_ba_cb(sdata, ra, tid);
887 
888 	rcu_read_lock();
889 	tid_tx = ieee80211_lookup_tid_tx(sdata, ra, tid, &sta);
890 	if (!tid_tx)
891 		goto out;
892 
893 	set_bit(HT_AGG_STATE_STOP_CB, &tid_tx->state);
894 	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
895  out:
896 	rcu_read_unlock();
897 }
898 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
899 
900 
901 void ieee80211_process_addba_resp(struct ieee80211_local *local,
902 				  struct sta_info *sta,
903 				  struct ieee80211_mgmt *mgmt,
904 				  size_t len)
905 {
906 	struct tid_ampdu_tx *tid_tx;
907 	struct ieee80211_txq *txq;
908 	u16 capab, tid;
909 	u8 buf_size;
910 	bool amsdu;
911 
912 	capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
913 	amsdu = capab & IEEE80211_ADDBA_PARAM_AMSDU_MASK;
914 	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
915 	buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
916 	buf_size = min(buf_size, local->hw.max_tx_aggregation_subframes);
917 
918 	txq = sta->sta.txq[tid];
919 	if (!amsdu && txq)
920 		set_bit(IEEE80211_TXQ_NO_AMSDU, &to_txq_info(txq)->flags);
921 
922 	mutex_lock(&sta->ampdu_mlme.mtx);
923 
924 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
925 	if (!tid_tx)
926 		goto out;
927 
928 	if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
929 		ht_dbg(sta->sdata, "wrong addBA response token, %pM tid %d\n",
930 		       sta->sta.addr, tid);
931 		goto out;
932 	}
933 
934 	del_timer_sync(&tid_tx->addba_resp_timer);
935 
936 	ht_dbg(sta->sdata, "switched off addBA timer for %pM tid %d\n",
937 	       sta->sta.addr, tid);
938 
939 	/*
940 	 * addba_resp_timer may have fired before we got here, and
941 	 * caused WANT_STOP to be set. If the stop then was already
942 	 * processed further, STOPPING might be set.
943 	 */
944 	if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
945 	    test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
946 		ht_dbg(sta->sdata,
947 		       "got addBA resp for %pM tid %d but we already gave up\n",
948 		       sta->sta.addr, tid);
949 		goto out;
950 	}
951 
952 	/*
953 	 * IEEE 802.11-2007 7.3.1.14:
954 	 * In an ADDBA Response frame, when the Status Code field
955 	 * is set to 0, the Buffer Size subfield is set to a value
956 	 * of at least 1.
957 	 */
958 	if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
959 			== WLAN_STATUS_SUCCESS && buf_size) {
960 		if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
961 				     &tid_tx->state)) {
962 			/* ignore duplicate response */
963 			goto out;
964 		}
965 
966 		tid_tx->buf_size = buf_size;
967 		tid_tx->amsdu = amsdu;
968 
969 		if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
970 			ieee80211_agg_tx_operational(local, sta, tid);
971 
972 		sta->ampdu_mlme.addba_req_num[tid] = 0;
973 
974 		tid_tx->timeout =
975 			le16_to_cpu(mgmt->u.action.u.addba_resp.timeout);
976 
977 		if (tid_tx->timeout) {
978 			mod_timer(&tid_tx->session_timer,
979 				  TU_TO_EXP_TIME(tid_tx->timeout));
980 			tid_tx->last_tx = jiffies;
981 		}
982 
983 	} else {
984 		___ieee80211_stop_tx_ba_session(sta, tid, AGG_STOP_DECLINED);
985 	}
986 
987  out:
988 	mutex_unlock(&sta->ampdu_mlme.mtx);
989 }
990