xref: /linux/net/mac80211/agg-tx.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * HT handling
4  *
5  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
6  * Copyright 2002-2005, Instant802 Networks, Inc.
7  * Copyright 2005-2006, Devicescape Software, Inc.
8  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
9  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
10  * Copyright 2007-2010, Intel Corporation
11  * Copyright(c) 2015-2017 Intel Deutschland GmbH
12  * Copyright (C) 2018 - 2023 Intel Corporation
13  */
14 
15 #include <linux/ieee80211.h>
16 #include <linux/slab.h>
17 #include <linux/export.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 A-MPDU aggregation
25  *
26  * Aggregation on the TX side requires setting the hardware flag
27  * %IEEE80211_HW_AMPDU_AGGREGATION. The driver will then be handed
28  * packets with a flag indicating A-MPDU aggregation. The driver
29  * or device is responsible for actually aggregating the frames,
30  * as well as deciding how many and which to aggregate.
31  *
32  * When TX aggregation is started by some subsystem (usually the rate
33  * control algorithm would be appropriate) by calling the
34  * ieee80211_start_tx_ba_session() function, the driver will be
35  * notified via its @ampdu_action function, with the
36  * %IEEE80211_AMPDU_TX_START action.
37  *
38  * In response to that, the driver is later required to call the
39  * ieee80211_start_tx_ba_cb_irqsafe() function, which will really
40  * start the aggregation session after the peer has also responded.
41  * If the peer responds negatively, the session will be stopped
42  * again right away. Note that it is possible for the aggregation
43  * session to be stopped before the driver has indicated that it
44  * is done setting it up, in which case it must not indicate the
45  * setup completion.
46  *
47  * Also note that, since we also need to wait for a response from
48  * the peer, the driver is notified of the completion of the
49  * handshake by the %IEEE80211_AMPDU_TX_OPERATIONAL action to the
50  * @ampdu_action callback.
51  *
52  * Similarly, when the aggregation session is stopped by the peer
53  * or something calling ieee80211_stop_tx_ba_session(), the driver's
54  * @ampdu_action function will be called with the action
55  * %IEEE80211_AMPDU_TX_STOP. In this case, the call must not fail,
56  * and the driver must later call ieee80211_stop_tx_ba_cb_irqsafe().
57  * Note that the sta can get destroyed before the BA tear down is
58  * complete.
59  */
60 
61 static void ieee80211_send_addba_request(struct sta_info *sta, u16 tid,
62 					 u8 dialog_token, u16 start_seq_num,
63 					 u16 agg_size, u16 timeout)
64 {
65 	struct ieee80211_sub_if_data *sdata = sta->sdata;
66 	struct ieee80211_local *local = sdata->local;
67 	struct sk_buff *skb;
68 	struct ieee80211_mgmt *mgmt;
69 	u16 capab;
70 
71 	skb = dev_alloc_skb(sizeof(*mgmt) +
72 			    2 + sizeof(struct ieee80211_addba_ext_ie) +
73 			    local->hw.extra_tx_headroom);
74 	if (!skb)
75 		return;
76 
77 	skb_reserve(skb, local->hw.extra_tx_headroom);
78 	mgmt = ieee80211_mgmt_ba(skb, sta->sta.addr, sdata);
79 
80 	skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
81 
82 	mgmt->u.action.category = WLAN_CATEGORY_BACK;
83 	mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
84 
85 	mgmt->u.action.u.addba_req.dialog_token = dialog_token;
86 	capab = IEEE80211_ADDBA_PARAM_AMSDU_MASK;
87 	capab |= IEEE80211_ADDBA_PARAM_POLICY_MASK;
88 	capab |= u16_encode_bits(tid, IEEE80211_ADDBA_PARAM_TID_MASK);
89 	capab |= u16_encode_bits(agg_size, IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK);
90 
91 	mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
92 
93 	mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
94 	mgmt->u.action.u.addba_req.start_seq_num =
95 					cpu_to_le16(start_seq_num << 4);
96 
97 	if (sta->sta.deflink.he_cap.has_he)
98 		ieee80211_add_addbaext(skb, 0, agg_size);
99 
100 	ieee80211_tx_skb_tid(sdata, skb, tid, -1);
101 }
102 
103 void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
104 {
105 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
106 	struct ieee80211_local *local = sdata->local;
107 	struct sk_buff *skb;
108 	struct ieee80211_bar *bar;
109 	u16 bar_control = 0;
110 
111 	skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
112 	if (!skb)
113 		return;
114 
115 	skb_reserve(skb, local->hw.extra_tx_headroom);
116 	bar = skb_put_zero(skb, sizeof(*bar));
117 	bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
118 					 IEEE80211_STYPE_BACK_REQ);
119 	memcpy(bar->ra, ra, ETH_ALEN);
120 	memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
121 	bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
122 	bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
123 	bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
124 	bar->control = cpu_to_le16(bar_control);
125 	bar->start_seq_num = cpu_to_le16(ssn);
126 
127 	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
128 					IEEE80211_TX_CTL_REQ_TX_STATUS;
129 	ieee80211_tx_skb_tid(sdata, skb, tid, -1);
130 }
131 EXPORT_SYMBOL(ieee80211_send_bar);
132 
133 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
134 			     struct tid_ampdu_tx *tid_tx)
135 {
136 	lockdep_assert_wiphy(sta->local->hw.wiphy);
137 	lockdep_assert_held(&sta->lock);
138 	rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
139 }
140 
141 /*
142  * When multiple aggregation sessions on multiple stations
143  * are being created/destroyed simultaneously, we need to
144  * refcount the global queue stop caused by that in order
145  * to not get into a situation where one of the aggregation
146  * setup or teardown re-enables queues before the other is
147  * ready to handle that.
148  *
149  * These two functions take care of this issue by keeping
150  * a global "agg_queue_stop" refcount.
151  */
152 static void __acquires(agg_queue)
153 ieee80211_stop_queue_agg(struct ieee80211_sub_if_data *sdata, int tid)
154 {
155 	int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
156 
157 	/* we do refcounting here, so don't use the queue reason refcounting */
158 
159 	if (atomic_inc_return(&sdata->local->agg_queue_stop[queue]) == 1)
160 		ieee80211_stop_queue_by_reason(
161 			&sdata->local->hw, queue,
162 			IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
163 			false);
164 	__acquire(agg_queue);
165 }
166 
167 static void __releases(agg_queue)
168 ieee80211_wake_queue_agg(struct ieee80211_sub_if_data *sdata, int tid)
169 {
170 	int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
171 
172 	if (atomic_dec_return(&sdata->local->agg_queue_stop[queue]) == 0)
173 		ieee80211_wake_queue_by_reason(
174 			&sdata->local->hw, queue,
175 			IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
176 			false);
177 	__release(agg_queue);
178 }
179 
180 static void
181 ieee80211_agg_stop_txq(struct sta_info *sta, int tid)
182 {
183 	struct ieee80211_txq *txq = sta->sta.txq[tid];
184 	struct ieee80211_sub_if_data *sdata;
185 	struct fq *fq;
186 	struct txq_info *txqi;
187 
188 	if (!txq)
189 		return;
190 
191 	txqi = to_txq_info(txq);
192 	sdata = vif_to_sdata(txq->vif);
193 	fq = &sdata->local->fq;
194 
195 	/* Lock here to protect against further seqno updates on dequeue */
196 	spin_lock_bh(&fq->lock);
197 	set_bit(IEEE80211_TXQ_STOP, &txqi->flags);
198 	spin_unlock_bh(&fq->lock);
199 }
200 
201 static void
202 ieee80211_agg_start_txq(struct sta_info *sta, int tid, bool enable)
203 {
204 	struct ieee80211_txq *txq = sta->sta.txq[tid];
205 	struct txq_info *txqi;
206 
207 	lockdep_assert_wiphy(sta->local->hw.wiphy);
208 
209 	if (!txq)
210 		return;
211 
212 	txqi = to_txq_info(txq);
213 
214 	if (enable)
215 		set_bit(IEEE80211_TXQ_AMPDU, &txqi->flags);
216 	else
217 		clear_bit(IEEE80211_TXQ_AMPDU, &txqi->flags);
218 
219 	clear_bit(IEEE80211_TXQ_STOP, &txqi->flags);
220 	local_bh_disable();
221 	rcu_read_lock();
222 	schedule_and_wake_txq(sta->sdata->local, txqi);
223 	rcu_read_unlock();
224 	local_bh_enable();
225 }
226 
227 /*
228  * splice packets from the STA's pending to the local pending,
229  * requires a call to ieee80211_agg_splice_finish later
230  */
231 static void __acquires(agg_queue)
232 ieee80211_agg_splice_packets(struct ieee80211_sub_if_data *sdata,
233 			     struct tid_ampdu_tx *tid_tx, u16 tid)
234 {
235 	struct ieee80211_local *local = sdata->local;
236 	int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
237 	unsigned long flags;
238 
239 	ieee80211_stop_queue_agg(sdata, tid);
240 
241 	if (WARN(!tid_tx,
242 		 "TID %d gone but expected when splicing aggregates from the pending queue\n",
243 		 tid))
244 		return;
245 
246 	if (!skb_queue_empty(&tid_tx->pending)) {
247 		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
248 		/* copy over remaining packets */
249 		skb_queue_splice_tail_init(&tid_tx->pending,
250 					   &local->pending[queue]);
251 		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
252 	}
253 }
254 
255 static void __releases(agg_queue)
256 ieee80211_agg_splice_finish(struct ieee80211_sub_if_data *sdata, u16 tid)
257 {
258 	ieee80211_wake_queue_agg(sdata, tid);
259 }
260 
261 static void ieee80211_remove_tid_tx(struct sta_info *sta, int tid)
262 {
263 	struct tid_ampdu_tx *tid_tx;
264 
265 	lockdep_assert_wiphy(sta->local->hw.wiphy);
266 	lockdep_assert_held(&sta->lock);
267 
268 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
269 
270 	/*
271 	 * When we get here, the TX path will not be lockless any more wrt.
272 	 * aggregation, since the OPERATIONAL bit has long been cleared.
273 	 * Thus it will block on getting the lock, if it occurs. So if we
274 	 * stop the queue now, we will not get any more packets, and any
275 	 * that might be being processed will wait for us here, thereby
276 	 * guaranteeing that no packets go to the tid_tx pending queue any
277 	 * more.
278 	 */
279 
280 	ieee80211_agg_splice_packets(sta->sdata, tid_tx, tid);
281 
282 	/* future packets must not find the tid_tx struct any more */
283 	ieee80211_assign_tid_tx(sta, tid, NULL);
284 
285 	ieee80211_agg_splice_finish(sta->sdata, tid);
286 
287 	kfree_rcu(tid_tx, rcu_head);
288 }
289 
290 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
291 				   enum ieee80211_agg_stop_reason reason)
292 {
293 	struct ieee80211_local *local = sta->local;
294 	struct tid_ampdu_tx *tid_tx;
295 	struct ieee80211_ampdu_params params = {
296 		.sta = &sta->sta,
297 		.tid = tid,
298 		.buf_size = 0,
299 		.amsdu = false,
300 		.timeout = 0,
301 		.ssn = 0,
302 	};
303 	int ret;
304 
305 	lockdep_assert_wiphy(sta->local->hw.wiphy);
306 
307 	switch (reason) {
308 	case AGG_STOP_DECLINED:
309 	case AGG_STOP_LOCAL_REQUEST:
310 	case AGG_STOP_PEER_REQUEST:
311 		params.action = IEEE80211_AMPDU_TX_STOP_CONT;
312 		break;
313 	case AGG_STOP_DESTROY_STA:
314 		params.action = IEEE80211_AMPDU_TX_STOP_FLUSH;
315 		break;
316 	default:
317 		WARN_ON_ONCE(1);
318 		return -EINVAL;
319 	}
320 
321 	spin_lock_bh(&sta->lock);
322 
323 	/* free struct pending for start, if present */
324 	tid_tx = sta->ampdu_mlme.tid_start_tx[tid];
325 	kfree(tid_tx);
326 	sta->ampdu_mlme.tid_start_tx[tid] = NULL;
327 
328 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
329 	if (!tid_tx) {
330 		spin_unlock_bh(&sta->lock);
331 		return -ENOENT;
332 	}
333 
334 	/*
335 	 * if we're already stopping ignore any new requests to stop
336 	 * unless we're destroying it in which case notify the driver
337 	 */
338 	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
339 		spin_unlock_bh(&sta->lock);
340 		if (reason != AGG_STOP_DESTROY_STA)
341 			return -EALREADY;
342 		params.action = IEEE80211_AMPDU_TX_STOP_FLUSH_CONT;
343 		ret = drv_ampdu_action(local, sta->sdata, &params);
344 		WARN_ON_ONCE(ret);
345 		return 0;
346 	}
347 
348 	if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
349 		/* not even started yet! */
350 		ieee80211_assign_tid_tx(sta, tid, NULL);
351 		spin_unlock_bh(&sta->lock);
352 		kfree_rcu(tid_tx, rcu_head);
353 		return 0;
354 	}
355 
356 	set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
357 
358 	ieee80211_agg_stop_txq(sta, tid);
359 
360 	spin_unlock_bh(&sta->lock);
361 
362 	ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
363 	       sta->sta.addr, tid);
364 
365 	del_timer_sync(&tid_tx->addba_resp_timer);
366 	del_timer_sync(&tid_tx->session_timer);
367 
368 	/*
369 	 * After this packets are no longer handed right through
370 	 * to the driver but are put onto tid_tx->pending instead,
371 	 * with locking to ensure proper access.
372 	 */
373 	clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
374 
375 	/*
376 	 * There might be a few packets being processed right now (on
377 	 * another CPU) that have already gotten past the aggregation
378 	 * check when it was still OPERATIONAL and consequently have
379 	 * IEEE80211_TX_CTL_AMPDU set. In that case, this code might
380 	 * call into the driver at the same time or even before the
381 	 * TX paths calls into it, which could confuse the driver.
382 	 *
383 	 * Wait for all currently running TX paths to finish before
384 	 * telling the driver. New packets will not go through since
385 	 * the aggregation session is no longer OPERATIONAL.
386 	 */
387 	if (!local->in_reconfig)
388 		synchronize_net();
389 
390 	tid_tx->stop_initiator = reason == AGG_STOP_PEER_REQUEST ?
391 					WLAN_BACK_RECIPIENT :
392 					WLAN_BACK_INITIATOR;
393 	tid_tx->tx_stop = reason == AGG_STOP_LOCAL_REQUEST;
394 
395 	ret = drv_ampdu_action(local, sta->sdata, &params);
396 
397 	/* HW shall not deny going back to legacy */
398 	if (WARN_ON(ret)) {
399 		/*
400 		 * We may have pending packets get stuck in this case...
401 		 * Not bothering with a workaround for now.
402 		 */
403 	}
404 
405 	/*
406 	 * In the case of AGG_STOP_DESTROY_STA, the driver won't
407 	 * necessarily call ieee80211_stop_tx_ba_cb(), so this may
408 	 * seem like we can leave the tid_tx data pending forever.
409 	 * This is true, in a way, but "forever" is only until the
410 	 * station struct is actually destroyed. In the meantime,
411 	 * leaving it around ensures that we don't transmit packets
412 	 * to the driver on this TID which might confuse it.
413 	 */
414 
415 	return 0;
416 }
417 
418 /*
419  * After sending add Block Ack request we activated a timer until
420  * add Block Ack response will arrive from the recipient.
421  * If this timer expires sta_addba_resp_timer_expired will be executed.
422  */
423 static void sta_addba_resp_timer_expired(struct timer_list *t)
424 {
425 	struct tid_ampdu_tx *tid_tx = from_timer(tid_tx, t, addba_resp_timer);
426 	struct sta_info *sta = tid_tx->sta;
427 	u8 tid = tid_tx->tid;
428 
429 	/* check if the TID waits for addBA response */
430 	if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
431 		ht_dbg(sta->sdata,
432 		       "timer expired on %pM tid %d not expecting addBA response\n",
433 		       sta->sta.addr, tid);
434 		return;
435 	}
436 
437 	ht_dbg(sta->sdata, "addBA response timer expired on %pM tid %d\n",
438 	       sta->sta.addr, tid);
439 
440 	ieee80211_stop_tx_ba_session(&sta->sta, tid);
441 }
442 
443 static void ieee80211_send_addba_with_timeout(struct sta_info *sta,
444 					      struct tid_ampdu_tx *tid_tx)
445 {
446 	struct ieee80211_sub_if_data *sdata = sta->sdata;
447 	struct ieee80211_local *local = sta->local;
448 	u8 tid = tid_tx->tid;
449 	u16 buf_size;
450 
451 	if (WARN_ON_ONCE(test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state) ||
452 			 test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state)))
453 		return;
454 
455 	lockdep_assert_wiphy(sta->local->hw.wiphy);
456 
457 	/* activate the timer for the recipient's addBA response */
458 	mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
459 	ht_dbg(sdata, "activated addBA response timer on %pM tid %d\n",
460 	       sta->sta.addr, tid);
461 
462 	spin_lock_bh(&sta->lock);
463 	sta->ampdu_mlme.last_addba_req_time[tid] = jiffies;
464 	sta->ampdu_mlme.addba_req_num[tid]++;
465 	spin_unlock_bh(&sta->lock);
466 
467 	if (sta->sta.deflink.eht_cap.has_eht) {
468 		buf_size = local->hw.max_tx_aggregation_subframes;
469 	} else if (sta->sta.deflink.he_cap.has_he) {
470 		buf_size = min_t(u16, local->hw.max_tx_aggregation_subframes,
471 				 IEEE80211_MAX_AMPDU_BUF_HE);
472 	} else {
473 		/*
474 		 * We really should use what the driver told us it will
475 		 * transmit as the maximum, but certain APs (e.g. the
476 		 * LinkSys WRT120N with FW v1.0.07 build 002 Jun 18 2012)
477 		 * will crash when we use a lower number.
478 		 */
479 		buf_size = IEEE80211_MAX_AMPDU_BUF_HT;
480 	}
481 
482 	/* send AddBA request */
483 	ieee80211_send_addba_request(sta, tid, tid_tx->dialog_token,
484 				     tid_tx->ssn, buf_size, tid_tx->timeout);
485 
486 	WARN_ON(test_and_set_bit(HT_AGG_STATE_SENT_ADDBA, &tid_tx->state));
487 }
488 
489 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
490 {
491 	struct tid_ampdu_tx *tid_tx;
492 	struct ieee80211_local *local = sta->local;
493 	struct ieee80211_sub_if_data *sdata = sta->sdata;
494 	struct ieee80211_ampdu_params params = {
495 		.sta = &sta->sta,
496 		.action = IEEE80211_AMPDU_TX_START,
497 		.tid = tid,
498 		.buf_size = 0,
499 		.amsdu = false,
500 		.timeout = 0,
501 	};
502 	int ret;
503 
504 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
505 
506 	/*
507 	 * Start queuing up packets for this aggregation session.
508 	 * We're going to release them once the driver is OK with
509 	 * that.
510 	 */
511 	clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
512 
513 	/*
514 	 * Make sure no packets are being processed. This ensures that
515 	 * we have a valid starting sequence number and that in-flight
516 	 * packets have been flushed out and no packets for this TID
517 	 * will go into the driver during the ampdu_action call.
518 	 */
519 	synchronize_net();
520 
521 	params.ssn = sta->tid_seq[tid] >> 4;
522 	ret = drv_ampdu_action(local, sdata, &params);
523 	tid_tx->ssn = params.ssn;
524 	if (ret == IEEE80211_AMPDU_TX_START_DELAY_ADDBA) {
525 		return;
526 	} else if (ret == IEEE80211_AMPDU_TX_START_IMMEDIATE) {
527 		/*
528 		 * We didn't send the request yet, so don't need to check
529 		 * here if we already got a response, just mark as driver
530 		 * ready immediately.
531 		 */
532 		set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state);
533 	} else if (ret) {
534 		ht_dbg(sdata,
535 		       "BA request denied - HW unavailable for %pM tid %d\n",
536 		       sta->sta.addr, tid);
537 		spin_lock_bh(&sta->lock);
538 		ieee80211_agg_splice_packets(sdata, tid_tx, tid);
539 		ieee80211_assign_tid_tx(sta, tid, NULL);
540 		ieee80211_agg_splice_finish(sdata, tid);
541 		spin_unlock_bh(&sta->lock);
542 
543 		ieee80211_agg_start_txq(sta, tid, false);
544 
545 		kfree_rcu(tid_tx, rcu_head);
546 		return;
547 	}
548 
549 	ieee80211_send_addba_with_timeout(sta, tid_tx);
550 }
551 
552 void ieee80211_refresh_tx_agg_session_timer(struct ieee80211_sta *pubsta,
553 					    u16 tid)
554 {
555 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
556 	struct tid_ampdu_tx *tid_tx;
557 
558 	if (WARN_ON_ONCE(tid >= IEEE80211_NUM_TIDS))
559 		return;
560 
561 	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
562 	if (!tid_tx)
563 		return;
564 
565 	tid_tx->last_tx = jiffies;
566 }
567 EXPORT_SYMBOL(ieee80211_refresh_tx_agg_session_timer);
568 
569 /*
570  * After accepting the AddBA Response we activated a timer,
571  * resetting it after each frame that we send.
572  */
573 static void sta_tx_agg_session_timer_expired(struct timer_list *t)
574 {
575 	struct tid_ampdu_tx *tid_tx = from_timer(tid_tx, t, session_timer);
576 	struct sta_info *sta = tid_tx->sta;
577 	u8 tid = tid_tx->tid;
578 	unsigned long timeout;
579 
580 	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
581 		return;
582 	}
583 
584 	timeout = tid_tx->last_tx + TU_TO_JIFFIES(tid_tx->timeout);
585 	if (time_is_after_jiffies(timeout)) {
586 		mod_timer(&tid_tx->session_timer, timeout);
587 		return;
588 	}
589 
590 	ht_dbg(sta->sdata, "tx session timer expired on %pM tid %d\n",
591 	       sta->sta.addr, tid);
592 
593 	ieee80211_stop_tx_ba_session(&sta->sta, tid);
594 }
595 
596 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
597 				  u16 timeout)
598 {
599 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
600 	struct ieee80211_sub_if_data *sdata = sta->sdata;
601 	struct ieee80211_local *local = sdata->local;
602 	struct tid_ampdu_tx *tid_tx;
603 	int ret = 0;
604 
605 	trace_api_start_tx_ba_session(pubsta, tid);
606 
607 	if (WARN(sta->reserved_tid == tid,
608 		 "Requested to start BA session on reserved tid=%d", tid))
609 		return -EINVAL;
610 
611 	if (!pubsta->deflink.ht_cap.ht_supported &&
612 	    !pubsta->deflink.vht_cap.vht_supported &&
613 	    !pubsta->deflink.he_cap.has_he &&
614 	    !pubsta->deflink.eht_cap.has_eht)
615 		return -EINVAL;
616 
617 	if (WARN_ON_ONCE(!local->ops->ampdu_action))
618 		return -EINVAL;
619 
620 	if ((tid >= IEEE80211_NUM_TIDS) ||
621 	    !ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION) ||
622 	    ieee80211_hw_check(&local->hw, TX_AMPDU_SETUP_IN_HW))
623 		return -EINVAL;
624 
625 	if (WARN_ON(tid >= IEEE80211_FIRST_TSPEC_TSID))
626 		return -EINVAL;
627 
628 	ht_dbg(sdata, "Open BA session requested for %pM tid %u\n",
629 	       pubsta->addr, tid);
630 
631 	if (sdata->vif.type != NL80211_IFTYPE_STATION &&
632 	    sdata->vif.type != NL80211_IFTYPE_MESH_POINT &&
633 	    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
634 	    sdata->vif.type != NL80211_IFTYPE_AP &&
635 	    sdata->vif.type != NL80211_IFTYPE_ADHOC)
636 		return -EINVAL;
637 
638 	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
639 		ht_dbg(sdata,
640 		       "BA sessions blocked - Denying BA session request %pM tid %d\n",
641 		       sta->sta.addr, tid);
642 		return -EINVAL;
643 	}
644 
645 	if (test_sta_flag(sta, WLAN_STA_MFP) &&
646 	    !test_sta_flag(sta, WLAN_STA_AUTHORIZED)) {
647 		ht_dbg(sdata,
648 		       "MFP STA not authorized - deny BA session request %pM tid %d\n",
649 		       sta->sta.addr, tid);
650 		return -EINVAL;
651 	}
652 
653 	/*
654 	 * 802.11n-2009 11.5.1.1: If the initiating STA is an HT STA, is a
655 	 * member of an IBSS, and has no other existing Block Ack agreement
656 	 * with the recipient STA, then the initiating STA shall transmit a
657 	 * Probe Request frame to the recipient STA and shall not transmit an
658 	 * ADDBA Request frame unless it receives a Probe Response frame
659 	 * from the recipient within dot11ADDBAFailureTimeout.
660 	 *
661 	 * The probe request mechanism for ADDBA is currently not implemented,
662 	 * but we only build up Block Ack session with HT STAs. This information
663 	 * is set when we receive a bss info from a probe response or a beacon.
664 	 */
665 	if (sta->sdata->vif.type == NL80211_IFTYPE_ADHOC &&
666 	    !sta->sta.deflink.ht_cap.ht_supported) {
667 		ht_dbg(sdata,
668 		       "BA request denied - IBSS STA %pM does not advertise HT support\n",
669 		       pubsta->addr);
670 		return -EINVAL;
671 	}
672 
673 	spin_lock_bh(&sta->lock);
674 
675 	/* we have tried too many times, receiver does not want A-MPDU */
676 	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
677 		ret = -EBUSY;
678 		goto err_unlock_sta;
679 	}
680 
681 	/*
682 	 * if we have tried more than HT_AGG_BURST_RETRIES times we
683 	 * will spread our requests in time to avoid stalling connection
684 	 * for too long
685 	 */
686 	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_BURST_RETRIES &&
687 	    time_before(jiffies, sta->ampdu_mlme.last_addba_req_time[tid] +
688 			HT_AGG_RETRIES_PERIOD)) {
689 		ht_dbg(sdata,
690 		       "BA request denied - %d failed requests on %pM tid %u\n",
691 		       sta->ampdu_mlme.addba_req_num[tid], sta->sta.addr, tid);
692 		ret = -EBUSY;
693 		goto err_unlock_sta;
694 	}
695 
696 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
697 	/* check if the TID is not in aggregation flow already */
698 	if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
699 		ht_dbg(sdata,
700 		       "BA request denied - session is not idle on %pM tid %u\n",
701 		       sta->sta.addr, tid);
702 		ret = -EAGAIN;
703 		goto err_unlock_sta;
704 	}
705 
706 	/* prepare A-MPDU MLME for Tx aggregation */
707 	tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
708 	if (!tid_tx) {
709 		ret = -ENOMEM;
710 		goto err_unlock_sta;
711 	}
712 
713 	skb_queue_head_init(&tid_tx->pending);
714 	__set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
715 
716 	tid_tx->timeout = timeout;
717 	tid_tx->sta = sta;
718 	tid_tx->tid = tid;
719 
720 	/* response timer */
721 	timer_setup(&tid_tx->addba_resp_timer, sta_addba_resp_timer_expired, 0);
722 
723 	/* tx timer */
724 	timer_setup(&tid_tx->session_timer,
725 		    sta_tx_agg_session_timer_expired, TIMER_DEFERRABLE);
726 
727 	/* assign a dialog token */
728 	sta->ampdu_mlme.dialog_token_allocator++;
729 	tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
730 
731 	/*
732 	 * Finally, assign it to the start array; the work item will
733 	 * collect it and move it to the normal array.
734 	 */
735 	sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
736 
737 	wiphy_work_queue(local->hw.wiphy, &sta->ampdu_mlme.work);
738 
739 	/* this flow continues off the work */
740  err_unlock_sta:
741 	spin_unlock_bh(&sta->lock);
742 	return ret;
743 }
744 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
745 
746 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
747 					 struct sta_info *sta, u16 tid)
748 {
749 	struct tid_ampdu_tx *tid_tx;
750 	struct ieee80211_ampdu_params params = {
751 		.sta = &sta->sta,
752 		.action = IEEE80211_AMPDU_TX_OPERATIONAL,
753 		.tid = tid,
754 		.timeout = 0,
755 		.ssn = 0,
756 	};
757 
758 	lockdep_assert_wiphy(sta->local->hw.wiphy);
759 
760 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
761 	params.buf_size = tid_tx->buf_size;
762 	params.amsdu = tid_tx->amsdu;
763 
764 	ht_dbg(sta->sdata, "Aggregation is on for %pM tid %d\n",
765 	       sta->sta.addr, tid);
766 
767 	drv_ampdu_action(local, sta->sdata, &params);
768 
769 	/*
770 	 * synchronize with TX path, while splicing the TX path
771 	 * should block so it won't put more packets onto pending.
772 	 */
773 	spin_lock_bh(&sta->lock);
774 
775 	ieee80211_agg_splice_packets(sta->sdata, tid_tx, tid);
776 	/*
777 	 * Now mark as operational. This will be visible
778 	 * in the TX path, and lets it go lock-free in
779 	 * the common case.
780 	 */
781 	set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
782 	ieee80211_agg_splice_finish(sta->sdata, tid);
783 
784 	spin_unlock_bh(&sta->lock);
785 
786 	ieee80211_agg_start_txq(sta, tid, true);
787 }
788 
789 void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
790 			      struct tid_ampdu_tx *tid_tx)
791 {
792 	struct ieee80211_sub_if_data *sdata = sta->sdata;
793 	struct ieee80211_local *local = sdata->local;
794 
795 	lockdep_assert_wiphy(sta->local->hw.wiphy);
796 
797 	if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
798 		return;
799 
800 	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state) ||
801 	    test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state))
802 		return;
803 
804 	if (!test_bit(HT_AGG_STATE_SENT_ADDBA, &tid_tx->state)) {
805 		ieee80211_send_addba_with_timeout(sta, tid_tx);
806 		/* RESPONSE_RECEIVED state would trigger the flow again */
807 		return;
808 	}
809 
810 	if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
811 		ieee80211_agg_tx_operational(local, sta, tid);
812 }
813 
814 static struct tid_ampdu_tx *
815 ieee80211_lookup_tid_tx(struct ieee80211_sub_if_data *sdata,
816 			const u8 *ra, u16 tid, struct sta_info **sta)
817 {
818 	struct tid_ampdu_tx *tid_tx;
819 
820 	if (tid >= IEEE80211_NUM_TIDS) {
821 		ht_dbg(sdata, "Bad TID value: tid = %d (>= %d)\n",
822 		       tid, IEEE80211_NUM_TIDS);
823 		return NULL;
824 	}
825 
826 	*sta = sta_info_get_bss(sdata, ra);
827 	if (!*sta) {
828 		ht_dbg(sdata, "Could not find station: %pM\n", ra);
829 		return NULL;
830 	}
831 
832 	tid_tx = rcu_dereference((*sta)->ampdu_mlme.tid_tx[tid]);
833 
834 	if (WARN_ON(!tid_tx))
835 		ht_dbg(sdata, "addBA was not requested!\n");
836 
837 	return tid_tx;
838 }
839 
840 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
841 				      const u8 *ra, u16 tid)
842 {
843 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
844 	struct ieee80211_local *local = sdata->local;
845 	struct sta_info *sta;
846 	struct tid_ampdu_tx *tid_tx;
847 
848 	trace_api_start_tx_ba_cb(sdata, ra, tid);
849 
850 	rcu_read_lock();
851 	tid_tx = ieee80211_lookup_tid_tx(sdata, ra, tid, &sta);
852 	if (!tid_tx)
853 		goto out;
854 
855 	set_bit(HT_AGG_STATE_START_CB, &tid_tx->state);
856 	wiphy_work_queue(local->hw.wiphy, &sta->ampdu_mlme.work);
857  out:
858 	rcu_read_unlock();
859 }
860 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
861 
862 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
863 {
864 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
865 	struct ieee80211_sub_if_data *sdata = sta->sdata;
866 	struct ieee80211_local *local = sdata->local;
867 	struct tid_ampdu_tx *tid_tx;
868 	int ret = 0;
869 
870 	trace_api_stop_tx_ba_session(pubsta, tid);
871 
872 	if (!local->ops->ampdu_action)
873 		return -EINVAL;
874 
875 	if (tid >= IEEE80211_NUM_TIDS)
876 		return -EINVAL;
877 
878 	spin_lock_bh(&sta->lock);
879 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
880 
881 	if (!tid_tx) {
882 		ret = -ENOENT;
883 		goto unlock;
884 	}
885 
886 	WARN(sta->reserved_tid == tid,
887 	     "Requested to stop BA session on reserved tid=%d", tid);
888 
889 	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
890 		/* already in progress stopping it */
891 		ret = 0;
892 		goto unlock;
893 	}
894 
895 	set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
896 	wiphy_work_queue(local->hw.wiphy, &sta->ampdu_mlme.work);
897 
898  unlock:
899 	spin_unlock_bh(&sta->lock);
900 	return ret;
901 }
902 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
903 
904 void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
905 			     struct tid_ampdu_tx *tid_tx)
906 {
907 	struct ieee80211_sub_if_data *sdata = sta->sdata;
908 	bool send_delba = false;
909 	bool start_txq = false;
910 
911 	ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
912 	       sta->sta.addr, tid);
913 
914 	spin_lock_bh(&sta->lock);
915 
916 	if (!test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
917 		ht_dbg(sdata,
918 		       "unexpected callback to A-MPDU stop for %pM tid %d\n",
919 		       sta->sta.addr, tid);
920 		goto unlock_sta;
921 	}
922 
923 	if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
924 		send_delba = true;
925 
926 	ieee80211_remove_tid_tx(sta, tid);
927 	start_txq = true;
928 
929  unlock_sta:
930 	spin_unlock_bh(&sta->lock);
931 
932 	if (start_txq)
933 		ieee80211_agg_start_txq(sta, tid, false);
934 
935 	if (send_delba)
936 		ieee80211_send_delba(sdata, sta->sta.addr, tid,
937 			WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
938 }
939 
940 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
941 				     const u8 *ra, u16 tid)
942 {
943 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
944 	struct ieee80211_local *local = sdata->local;
945 	struct sta_info *sta;
946 	struct tid_ampdu_tx *tid_tx;
947 
948 	trace_api_stop_tx_ba_cb(sdata, ra, tid);
949 
950 	rcu_read_lock();
951 	tid_tx = ieee80211_lookup_tid_tx(sdata, ra, tid, &sta);
952 	if (!tid_tx)
953 		goto out;
954 
955 	set_bit(HT_AGG_STATE_STOP_CB, &tid_tx->state);
956 	wiphy_work_queue(local->hw.wiphy, &sta->ampdu_mlme.work);
957  out:
958 	rcu_read_unlock();
959 }
960 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
961 
962 
963 void ieee80211_process_addba_resp(struct ieee80211_local *local,
964 				  struct sta_info *sta,
965 				  struct ieee80211_mgmt *mgmt,
966 				  size_t len)
967 {
968 	struct tid_ampdu_tx *tid_tx;
969 	struct ieee80211_txq *txq;
970 	u16 capab, tid, buf_size;
971 	bool amsdu;
972 
973 	lockdep_assert_wiphy(sta->local->hw.wiphy);
974 
975 	capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
976 	amsdu = capab & IEEE80211_ADDBA_PARAM_AMSDU_MASK;
977 	tid = u16_get_bits(capab, IEEE80211_ADDBA_PARAM_TID_MASK);
978 	buf_size = u16_get_bits(capab, IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK);
979 
980 	ieee80211_retrieve_addba_ext_data(sta,
981 					  mgmt->u.action.u.addba_resp.variable,
982 					  len - offsetof(typeof(*mgmt),
983 							 u.action.u.addba_resp.variable),
984 					  &buf_size);
985 
986 	buf_size = min(buf_size, local->hw.max_tx_aggregation_subframes);
987 
988 	txq = sta->sta.txq[tid];
989 	if (!amsdu && txq)
990 		set_bit(IEEE80211_TXQ_NO_AMSDU, &to_txq_info(txq)->flags);
991 
992 	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
993 	if (!tid_tx)
994 		return;
995 
996 	if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
997 		ht_dbg(sta->sdata, "wrong addBA response token, %pM tid %d\n",
998 		       sta->sta.addr, tid);
999 		return;
1000 	}
1001 
1002 	del_timer_sync(&tid_tx->addba_resp_timer);
1003 
1004 	ht_dbg(sta->sdata, "switched off addBA timer for %pM tid %d\n",
1005 	       sta->sta.addr, tid);
1006 
1007 	/*
1008 	 * addba_resp_timer may have fired before we got here, and
1009 	 * caused WANT_STOP to be set. If the stop then was already
1010 	 * processed further, STOPPING might be set.
1011 	 */
1012 	if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
1013 	    test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
1014 		ht_dbg(sta->sdata,
1015 		       "got addBA resp for %pM tid %d but we already gave up\n",
1016 		       sta->sta.addr, tid);
1017 		return;
1018 	}
1019 
1020 	/*
1021 	 * IEEE 802.11-2007 7.3.1.14:
1022 	 * In an ADDBA Response frame, when the Status Code field
1023 	 * is set to 0, the Buffer Size subfield is set to a value
1024 	 * of at least 1.
1025 	 */
1026 	if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
1027 			== WLAN_STATUS_SUCCESS && buf_size) {
1028 		if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
1029 				     &tid_tx->state)) {
1030 			/* ignore duplicate response */
1031 			return;
1032 		}
1033 
1034 		tid_tx->buf_size = buf_size;
1035 		tid_tx->amsdu = amsdu;
1036 
1037 		if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
1038 			ieee80211_agg_tx_operational(local, sta, tid);
1039 
1040 		sta->ampdu_mlme.addba_req_num[tid] = 0;
1041 
1042 		tid_tx->timeout =
1043 			le16_to_cpu(mgmt->u.action.u.addba_resp.timeout);
1044 
1045 		if (tid_tx->timeout) {
1046 			mod_timer(&tid_tx->session_timer,
1047 				  TU_TO_EXP_TIME(tid_tx->timeout));
1048 			tid_tx->last_tx = jiffies;
1049 		}
1050 
1051 	} else {
1052 		__ieee80211_stop_tx_ba_session(sta, tid, AGG_STOP_DECLINED);
1053 	}
1054 }
1055