xref: /kernel/linux/linux-5.10/net/mac80211/agg-tx.c (revision 8c2ecf20)
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 - 2022 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
61static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
62					 const u8 *da, u16 tid,
63					 u8 dialog_token, u16 start_seq_num,
64					 u16 agg_size, u16 timeout)
65{
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) + local->hw.extra_tx_headroom);
72
73	if (!skb)
74		return;
75
76	skb_reserve(skb, local->hw.extra_tx_headroom);
77	mgmt = skb_put_zero(skb, 24);
78	memcpy(mgmt->da, da, ETH_ALEN);
79	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
80	if (sdata->vif.type == NL80211_IFTYPE_AP ||
81	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
82	    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
83		memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
84	else if (sdata->vif.type == NL80211_IFTYPE_STATION)
85		memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
86	else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
87		memcpy(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN);
88
89	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
90					  IEEE80211_STYPE_ACTION);
91
92	skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
93
94	mgmt->u.action.category = WLAN_CATEGORY_BACK;
95	mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
96
97	mgmt->u.action.u.addba_req.dialog_token = dialog_token;
98	capab = (u16)(1 << 0);		/* bit 0 A-MSDU support */
99	capab |= (u16)(1 << 1);		/* bit 1 aggregation policy */
100	capab |= (u16)(tid << 2); 	/* bit 5:2 TID number */
101	capab |= (u16)(agg_size << 6);	/* bit 15:6 max size of aggergation */
102
103	mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
104
105	mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
106	mgmt->u.action.u.addba_req.start_seq_num =
107					cpu_to_le16(start_seq_num << 4);
108
109	ieee80211_tx_skb_tid(sdata, skb, tid);
110}
111
112void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
113{
114	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
115	struct ieee80211_local *local = sdata->local;
116	struct sk_buff *skb;
117	struct ieee80211_bar *bar;
118	u16 bar_control = 0;
119
120	skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
121	if (!skb)
122		return;
123
124	skb_reserve(skb, local->hw.extra_tx_headroom);
125	bar = skb_put_zero(skb, sizeof(*bar));
126	bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
127					 IEEE80211_STYPE_BACK_REQ);
128	memcpy(bar->ra, ra, ETH_ALEN);
129	memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
130	bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
131	bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
132	bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
133	bar->control = cpu_to_le16(bar_control);
134	bar->start_seq_num = cpu_to_le16(ssn);
135
136	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
137					IEEE80211_TX_CTL_REQ_TX_STATUS;
138	ieee80211_tx_skb_tid(sdata, skb, tid);
139}
140EXPORT_SYMBOL(ieee80211_send_bar);
141
142void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
143			     struct tid_ampdu_tx *tid_tx)
144{
145	lockdep_assert_held(&sta->ampdu_mlme.mtx);
146	lockdep_assert_held(&sta->lock);
147	rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
148}
149
150/*
151 * When multiple aggregation sessions on multiple stations
152 * are being created/destroyed simultaneously, we need to
153 * refcount the global queue stop caused by that in order
154 * to not get into a situation where one of the aggregation
155 * setup or teardown re-enables queues before the other is
156 * ready to handle that.
157 *
158 * These two functions take care of this issue by keeping
159 * a global "agg_queue_stop" refcount.
160 */
161static void __acquires(agg_queue)
162ieee80211_stop_queue_agg(struct ieee80211_sub_if_data *sdata, int tid)
163{
164	int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
165
166	/* we do refcounting here, so don't use the queue reason refcounting */
167
168	if (atomic_inc_return(&sdata->local->agg_queue_stop[queue]) == 1)
169		ieee80211_stop_queue_by_reason(
170			&sdata->local->hw, queue,
171			IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
172			false);
173	__acquire(agg_queue);
174}
175
176static void __releases(agg_queue)
177ieee80211_wake_queue_agg(struct ieee80211_sub_if_data *sdata, int tid)
178{
179	int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
180
181	if (atomic_dec_return(&sdata->local->agg_queue_stop[queue]) == 0)
182		ieee80211_wake_queue_by_reason(
183			&sdata->local->hw, queue,
184			IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
185			false);
186	__release(agg_queue);
187}
188
189static void
190ieee80211_agg_stop_txq(struct sta_info *sta, int tid)
191{
192	struct ieee80211_txq *txq = sta->sta.txq[tid];
193	struct ieee80211_sub_if_data *sdata;
194	struct fq *fq;
195	struct txq_info *txqi;
196
197	if (!txq)
198		return;
199
200	txqi = to_txq_info(txq);
201	sdata = vif_to_sdata(txq->vif);
202	fq = &sdata->local->fq;
203
204	/* Lock here to protect against further seqno updates on dequeue */
205	spin_lock_bh(&fq->lock);
206	set_bit(IEEE80211_TXQ_STOP, &txqi->flags);
207	spin_unlock_bh(&fq->lock);
208}
209
210static void
211ieee80211_agg_start_txq(struct sta_info *sta, int tid, bool enable)
212{
213	struct ieee80211_txq *txq = sta->sta.txq[tid];
214	struct txq_info *txqi;
215
216	lockdep_assert_held(&sta->ampdu_mlme.mtx);
217
218	if (!txq)
219		return;
220
221	txqi = to_txq_info(txq);
222
223	if (enable)
224		set_bit(IEEE80211_TXQ_AMPDU, &txqi->flags);
225	else
226		clear_bit(IEEE80211_TXQ_AMPDU, &txqi->flags);
227
228	clear_bit(IEEE80211_TXQ_STOP, &txqi->flags);
229	local_bh_disable();
230	rcu_read_lock();
231	schedule_and_wake_txq(sta->sdata->local, txqi);
232	rcu_read_unlock();
233	local_bh_enable();
234}
235
236/*
237 * splice packets from the STA's pending to the local pending,
238 * requires a call to ieee80211_agg_splice_finish later
239 */
240static void __acquires(agg_queue)
241ieee80211_agg_splice_packets(struct ieee80211_sub_if_data *sdata,
242			     struct tid_ampdu_tx *tid_tx, u16 tid)
243{
244	struct ieee80211_local *local = sdata->local;
245	int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
246	unsigned long flags;
247
248	ieee80211_stop_queue_agg(sdata, tid);
249
250	if (WARN(!tid_tx,
251		 "TID %d gone but expected when splicing aggregates from the pending queue\n",
252		 tid))
253		return;
254
255	if (!skb_queue_empty(&tid_tx->pending)) {
256		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
257		/* copy over remaining packets */
258		skb_queue_splice_tail_init(&tid_tx->pending,
259					   &local->pending[queue]);
260		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
261	}
262}
263
264static void __releases(agg_queue)
265ieee80211_agg_splice_finish(struct ieee80211_sub_if_data *sdata, u16 tid)
266{
267	ieee80211_wake_queue_agg(sdata, tid);
268}
269
270static void ieee80211_remove_tid_tx(struct sta_info *sta, int tid)
271{
272	struct tid_ampdu_tx *tid_tx;
273
274	lockdep_assert_held(&sta->ampdu_mlme.mtx);
275	lockdep_assert_held(&sta->lock);
276
277	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
278
279	/*
280	 * When we get here, the TX path will not be lockless any more wrt.
281	 * aggregation, since the OPERATIONAL bit has long been cleared.
282	 * Thus it will block on getting the lock, if it occurs. So if we
283	 * stop the queue now, we will not get any more packets, and any
284	 * that might be being processed will wait for us here, thereby
285	 * guaranteeing that no packets go to the tid_tx pending queue any
286	 * more.
287	 */
288
289	ieee80211_agg_splice_packets(sta->sdata, tid_tx, tid);
290
291	/* future packets must not find the tid_tx struct any more */
292	ieee80211_assign_tid_tx(sta, tid, NULL);
293
294	ieee80211_agg_splice_finish(sta->sdata, tid);
295
296	kfree_rcu(tid_tx, rcu_head);
297}
298
299int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
300				    enum ieee80211_agg_stop_reason reason)
301{
302	struct ieee80211_local *local = sta->local;
303	struct tid_ampdu_tx *tid_tx;
304	struct ieee80211_ampdu_params params = {
305		.sta = &sta->sta,
306		.tid = tid,
307		.buf_size = 0,
308		.amsdu = false,
309		.timeout = 0,
310		.ssn = 0,
311	};
312	int ret;
313
314	lockdep_assert_held(&sta->ampdu_mlme.mtx);
315
316	switch (reason) {
317	case AGG_STOP_DECLINED:
318	case AGG_STOP_LOCAL_REQUEST:
319	case AGG_STOP_PEER_REQUEST:
320		params.action = IEEE80211_AMPDU_TX_STOP_CONT;
321		break;
322	case AGG_STOP_DESTROY_STA:
323		params.action = IEEE80211_AMPDU_TX_STOP_FLUSH;
324		break;
325	default:
326		WARN_ON_ONCE(1);
327		return -EINVAL;
328	}
329
330	spin_lock_bh(&sta->lock);
331
332	/* free struct pending for start, if present */
333	tid_tx = sta->ampdu_mlme.tid_start_tx[tid];
334	kfree(tid_tx);
335	sta->ampdu_mlme.tid_start_tx[tid] = NULL;
336
337	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
338	if (!tid_tx) {
339		spin_unlock_bh(&sta->lock);
340		return -ENOENT;
341	}
342
343	/*
344	 * if we're already stopping ignore any new requests to stop
345	 * unless we're destroying it in which case notify the driver
346	 */
347	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
348		spin_unlock_bh(&sta->lock);
349		if (reason != AGG_STOP_DESTROY_STA)
350			return -EALREADY;
351		params.action = IEEE80211_AMPDU_TX_STOP_FLUSH_CONT;
352		ret = drv_ampdu_action(local, sta->sdata, &params);
353		WARN_ON_ONCE(ret);
354		return 0;
355	}
356
357	if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
358		/* not even started yet! */
359		ieee80211_assign_tid_tx(sta, tid, NULL);
360		spin_unlock_bh(&sta->lock);
361		kfree_rcu(tid_tx, rcu_head);
362		return 0;
363	}
364
365	set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
366
367	ieee80211_agg_stop_txq(sta, tid);
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 */
432static 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
452static void ieee80211_send_addba_with_timeout(struct sta_info *sta,
453					      struct tid_ampdu_tx *tid_tx)
454{
455	struct ieee80211_sub_if_data *sdata = sta->sdata;
456	struct ieee80211_local *local = sta->local;
457	u8 tid = tid_tx->tid;
458	u16 buf_size;
459
460	/* activate the timer for the recipient's addBA response */
461	mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
462	ht_dbg(sdata, "activated addBA response timer on %pM tid %d\n",
463	       sta->sta.addr, tid);
464
465	spin_lock_bh(&sta->lock);
466	sta->ampdu_mlme.last_addba_req_time[tid] = jiffies;
467	sta->ampdu_mlme.addba_req_num[tid]++;
468	spin_unlock_bh(&sta->lock);
469
470	if (sta->sta.he_cap.has_he) {
471		buf_size = local->hw.max_tx_aggregation_subframes;
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(sdata, sta->sta.addr, tid,
484				     tid_tx->dialog_token, tid_tx->ssn,
485				     buf_size, tid_tx->timeout);
486
487	WARN_ON(test_and_set_bit(HT_AGG_STATE_SENT_ADDBA, &tid_tx->state));
488}
489
490void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
491{
492	struct tid_ampdu_tx *tid_tx;
493	struct ieee80211_local *local = sta->local;
494	struct ieee80211_sub_if_data *sdata;
495	struct ieee80211_ampdu_params params = {
496		.sta = &sta->sta,
497		.action = IEEE80211_AMPDU_TX_START,
498		.tid = tid,
499		.buf_size = 0,
500		.amsdu = false,
501		.timeout = 0,
502	};
503	int ret;
504
505	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
506
507	/*
508	 * Start queuing up packets for this aggregation session.
509	 * We're going to release them once the driver is OK with
510	 * that.
511	 */
512	clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
513
514	ieee80211_agg_stop_txq(sta, tid);
515
516	/*
517	 * Make sure no packets are being processed. This ensures that
518	 * we have a valid starting sequence number and that in-flight
519	 * packets have been flushed out and no packets for this TID
520	 * will go into the driver during the ampdu_action call.
521	 */
522	synchronize_net();
523
524	sdata = sta->sdata;
525	params.ssn = sta->tid_seq[tid] >> 4;
526	ret = drv_ampdu_action(local, sdata, &params);
527	tid_tx->ssn = params.ssn;
528	if (ret == IEEE80211_AMPDU_TX_START_DELAY_ADDBA) {
529		return;
530	} else if (ret == IEEE80211_AMPDU_TX_START_IMMEDIATE) {
531		/*
532		 * We didn't send the request yet, so don't need to check
533		 * here if we already got a response, just mark as driver
534		 * ready immediately.
535		 */
536		set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state);
537	} else if (ret) {
538		if (!sdata)
539			return;
540
541		ht_dbg(sdata,
542		       "BA request denied - HW unavailable for %pM tid %d\n",
543		       sta->sta.addr, tid);
544		spin_lock_bh(&sta->lock);
545		ieee80211_agg_splice_packets(sdata, tid_tx, tid);
546		ieee80211_assign_tid_tx(sta, tid, NULL);
547		ieee80211_agg_splice_finish(sdata, tid);
548		spin_unlock_bh(&sta->lock);
549
550		ieee80211_agg_start_txq(sta, tid, false);
551
552		kfree_rcu(tid_tx, rcu_head);
553		return;
554	}
555
556	ieee80211_send_addba_with_timeout(sta, tid_tx);
557}
558
559/*
560 * After accepting the AddBA Response we activated a timer,
561 * resetting it after each frame that we send.
562 */
563static void sta_tx_agg_session_timer_expired(struct timer_list *t)
564{
565	struct tid_ampdu_tx *tid_tx = from_timer(tid_tx, t, session_timer);
566	struct sta_info *sta = tid_tx->sta;
567	u8 tid = tid_tx->tid;
568	unsigned long timeout;
569
570	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
571		return;
572	}
573
574	timeout = tid_tx->last_tx + TU_TO_JIFFIES(tid_tx->timeout);
575	if (time_is_after_jiffies(timeout)) {
576		mod_timer(&tid_tx->session_timer, timeout);
577		return;
578	}
579
580	ht_dbg(sta->sdata, "tx session timer expired on %pM tid %d\n",
581	       sta->sta.addr, tid);
582
583	ieee80211_stop_tx_ba_session(&sta->sta, tid);
584}
585
586int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
587				  u16 timeout)
588{
589	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
590	struct ieee80211_sub_if_data *sdata = sta->sdata;
591	struct ieee80211_local *local = sdata->local;
592	struct tid_ampdu_tx *tid_tx;
593	int ret = 0;
594
595	trace_api_start_tx_ba_session(pubsta, tid);
596
597	if (WARN(sta->reserved_tid == tid,
598		 "Requested to start BA session on reserved tid=%d", tid))
599		return -EINVAL;
600
601	if (!pubsta->ht_cap.ht_supported &&
602	    sta->sdata->vif.bss_conf.chandef.chan->band != NL80211_BAND_6GHZ)
603		return -EINVAL;
604
605	if (WARN_ON_ONCE(!local->ops->ampdu_action))
606		return -EINVAL;
607
608	if ((tid >= IEEE80211_NUM_TIDS) ||
609	    !ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION) ||
610	    ieee80211_hw_check(&local->hw, TX_AMPDU_SETUP_IN_HW))
611		return -EINVAL;
612
613	if (WARN_ON(tid >= IEEE80211_FIRST_TSPEC_TSID))
614		return -EINVAL;
615
616	ht_dbg(sdata, "Open BA session requested for %pM tid %u\n",
617	       pubsta->addr, tid);
618
619	if (sdata->vif.type != NL80211_IFTYPE_STATION &&
620	    sdata->vif.type != NL80211_IFTYPE_MESH_POINT &&
621	    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
622	    sdata->vif.type != NL80211_IFTYPE_AP &&
623	    sdata->vif.type != NL80211_IFTYPE_ADHOC)
624		return -EINVAL;
625
626	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
627		ht_dbg(sdata,
628		       "BA sessions blocked - Denying BA session request %pM tid %d\n",
629		       sta->sta.addr, tid);
630		return -EINVAL;
631	}
632
633	if (test_sta_flag(sta, WLAN_STA_MFP) &&
634	    !test_sta_flag(sta, WLAN_STA_AUTHORIZED)) {
635		ht_dbg(sdata,
636		       "MFP STA not authorized - deny BA session request %pM tid %d\n",
637		       sta->sta.addr, tid);
638		return -EINVAL;
639	}
640
641	/*
642	 * 802.11n-2009 11.5.1.1: If the initiating STA is an HT STA, is a
643	 * member of an IBSS, and has no other existing Block Ack agreement
644	 * with the recipient STA, then the initiating STA shall transmit a
645	 * Probe Request frame to the recipient STA and shall not transmit an
646	 * ADDBA Request frame unless it receives a Probe Response frame
647	 * from the recipient within dot11ADDBAFailureTimeout.
648	 *
649	 * The probe request mechanism for ADDBA is currently not implemented,
650	 * but we only build up Block Ack session with HT STAs. This information
651	 * is set when we receive a bss info from a probe response or a beacon.
652	 */
653	if (sta->sdata->vif.type == NL80211_IFTYPE_ADHOC &&
654	    !sta->sta.ht_cap.ht_supported) {
655		ht_dbg(sdata,
656		       "BA request denied - IBSS STA %pM does not advertise HT support\n",
657		       pubsta->addr);
658		return -EINVAL;
659	}
660
661	spin_lock_bh(&sta->lock);
662
663	/* we have tried too many times, receiver does not want A-MPDU */
664	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
665		ret = -EBUSY;
666		goto err_unlock_sta;
667	}
668
669	/*
670	 * if we have tried more than HT_AGG_BURST_RETRIES times we
671	 * will spread our requests in time to avoid stalling connection
672	 * for too long
673	 */
674	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_BURST_RETRIES &&
675	    time_before(jiffies, sta->ampdu_mlme.last_addba_req_time[tid] +
676			HT_AGG_RETRIES_PERIOD)) {
677		ht_dbg(sdata,
678		       "BA request denied - %d failed requests on %pM tid %u\n",
679		       sta->ampdu_mlme.addba_req_num[tid], sta->sta.addr, tid);
680		ret = -EBUSY;
681		goto err_unlock_sta;
682	}
683
684	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
685	/* check if the TID is not in aggregation flow already */
686	if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
687		ht_dbg(sdata,
688		       "BA request denied - session is not idle on %pM tid %u\n",
689		       sta->sta.addr, tid);
690		ret = -EAGAIN;
691		goto err_unlock_sta;
692	}
693
694	/* prepare A-MPDU MLME for Tx aggregation */
695	tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
696	if (!tid_tx) {
697		ret = -ENOMEM;
698		goto err_unlock_sta;
699	}
700
701	skb_queue_head_init(&tid_tx->pending);
702	__set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
703
704	tid_tx->timeout = timeout;
705	tid_tx->sta = sta;
706	tid_tx->tid = tid;
707
708	/* response timer */
709	timer_setup(&tid_tx->addba_resp_timer, sta_addba_resp_timer_expired, 0);
710
711	/* tx timer */
712	timer_setup(&tid_tx->session_timer,
713		    sta_tx_agg_session_timer_expired, TIMER_DEFERRABLE);
714
715	/* assign a dialog token */
716	sta->ampdu_mlme.dialog_token_allocator++;
717	tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
718
719	/*
720	 * Finally, assign it to the start array; the work item will
721	 * collect it and move it to the normal array.
722	 */
723	sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
724
725	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
726
727	/* this flow continues off the work */
728 err_unlock_sta:
729	spin_unlock_bh(&sta->lock);
730	return ret;
731}
732EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
733
734static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
735					 struct sta_info *sta, u16 tid)
736{
737	struct tid_ampdu_tx *tid_tx;
738	struct ieee80211_ampdu_params params = {
739		.sta = &sta->sta,
740		.action = IEEE80211_AMPDU_TX_OPERATIONAL,
741		.tid = tid,
742		.timeout = 0,
743		.ssn = 0,
744	};
745
746	lockdep_assert_held(&sta->ampdu_mlme.mtx);
747
748	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
749	params.buf_size = tid_tx->buf_size;
750	params.amsdu = tid_tx->amsdu;
751
752	ht_dbg(sta->sdata, "Aggregation is on for %pM tid %d\n",
753	       sta->sta.addr, tid);
754
755	drv_ampdu_action(local, sta->sdata, &params);
756
757	/*
758	 * synchronize with TX path, while splicing the TX path
759	 * should block so it won't put more packets onto pending.
760	 */
761	spin_lock_bh(&sta->lock);
762
763	ieee80211_agg_splice_packets(sta->sdata, tid_tx, tid);
764	/*
765	 * Now mark as operational. This will be visible
766	 * in the TX path, and lets it go lock-free in
767	 * the common case.
768	 */
769	set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
770	ieee80211_agg_splice_finish(sta->sdata, tid);
771
772	spin_unlock_bh(&sta->lock);
773
774	ieee80211_agg_start_txq(sta, tid, true);
775}
776
777void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
778			      struct tid_ampdu_tx *tid_tx)
779{
780	struct ieee80211_sub_if_data *sdata = sta->sdata;
781	struct ieee80211_local *local = sdata->local;
782
783	if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
784		return;
785
786	if (!test_bit(HT_AGG_STATE_SENT_ADDBA, &tid_tx->state)) {
787		ieee80211_send_addba_with_timeout(sta, tid_tx);
788		/* RESPONSE_RECEIVED state whould trigger the flow again */
789		return;
790	}
791
792	if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
793		ieee80211_agg_tx_operational(local, sta, tid);
794}
795
796static struct tid_ampdu_tx *
797ieee80211_lookup_tid_tx(struct ieee80211_sub_if_data *sdata,
798			const u8 *ra, u16 tid, struct sta_info **sta)
799{
800	struct tid_ampdu_tx *tid_tx;
801
802	if (tid >= IEEE80211_NUM_TIDS) {
803		ht_dbg(sdata, "Bad TID value: tid = %d (>= %d)\n",
804		       tid, IEEE80211_NUM_TIDS);
805		return NULL;
806	}
807
808	*sta = sta_info_get_bss(sdata, ra);
809	if (!*sta) {
810		ht_dbg(sdata, "Could not find station: %pM\n", ra);
811		return NULL;
812	}
813
814	tid_tx = rcu_dereference((*sta)->ampdu_mlme.tid_tx[tid]);
815
816	if (WARN_ON(!tid_tx))
817		ht_dbg(sdata, "addBA was not requested!\n");
818
819	return tid_tx;
820}
821
822void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
823				      const u8 *ra, u16 tid)
824{
825	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
826	struct ieee80211_local *local = sdata->local;
827	struct sta_info *sta;
828	struct tid_ampdu_tx *tid_tx;
829
830	trace_api_start_tx_ba_cb(sdata, ra, tid);
831
832	rcu_read_lock();
833	tid_tx = ieee80211_lookup_tid_tx(sdata, ra, tid, &sta);
834	if (!tid_tx)
835		goto out;
836
837	set_bit(HT_AGG_STATE_START_CB, &tid_tx->state);
838	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
839 out:
840	rcu_read_unlock();
841}
842EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
843
844int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
845				   enum ieee80211_agg_stop_reason reason)
846{
847	int ret;
848
849	mutex_lock(&sta->ampdu_mlme.mtx);
850
851	ret = ___ieee80211_stop_tx_ba_session(sta, tid, reason);
852
853	mutex_unlock(&sta->ampdu_mlme.mtx);
854
855	return ret;
856}
857
858int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
859{
860	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
861	struct ieee80211_sub_if_data *sdata = sta->sdata;
862	struct ieee80211_local *local = sdata->local;
863	struct tid_ampdu_tx *tid_tx;
864	int ret = 0;
865
866	trace_api_stop_tx_ba_session(pubsta, tid);
867
868	if (!local->ops->ampdu_action)
869		return -EINVAL;
870
871	if (tid >= IEEE80211_NUM_TIDS)
872		return -EINVAL;
873
874	spin_lock_bh(&sta->lock);
875	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
876
877	if (!tid_tx) {
878		ret = -ENOENT;
879		goto unlock;
880	}
881
882	WARN(sta->reserved_tid == tid,
883	     "Requested to stop BA session on reserved tid=%d", tid);
884
885	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
886		/* already in progress stopping it */
887		ret = 0;
888		goto unlock;
889	}
890
891	set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
892	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
893
894 unlock:
895	spin_unlock_bh(&sta->lock);
896	return ret;
897}
898EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
899
900void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
901			     struct tid_ampdu_tx *tid_tx)
902{
903	struct ieee80211_sub_if_data *sdata = sta->sdata;
904	bool send_delba = false;
905	bool start_txq = false;
906
907	ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
908	       sta->sta.addr, tid);
909
910	spin_lock_bh(&sta->lock);
911
912	if (!test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
913		ht_dbg(sdata,
914		       "unexpected callback to A-MPDU stop for %pM tid %d\n",
915		       sta->sta.addr, tid);
916		goto unlock_sta;
917	}
918
919	if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
920		send_delba = true;
921
922	ieee80211_remove_tid_tx(sta, tid);
923	start_txq = true;
924
925 unlock_sta:
926	spin_unlock_bh(&sta->lock);
927
928	if (start_txq)
929		ieee80211_agg_start_txq(sta, tid, false);
930
931	if (send_delba)
932		ieee80211_send_delba(sdata, sta->sta.addr, tid,
933			WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
934}
935
936void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
937				     const u8 *ra, u16 tid)
938{
939	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
940	struct ieee80211_local *local = sdata->local;
941	struct sta_info *sta;
942	struct tid_ampdu_tx *tid_tx;
943
944	trace_api_stop_tx_ba_cb(sdata, ra, tid);
945
946	rcu_read_lock();
947	tid_tx = ieee80211_lookup_tid_tx(sdata, ra, tid, &sta);
948	if (!tid_tx)
949		goto out;
950
951	set_bit(HT_AGG_STATE_STOP_CB, &tid_tx->state);
952	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
953 out:
954	rcu_read_unlock();
955}
956EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
957
958
959void ieee80211_process_addba_resp(struct ieee80211_local *local,
960				  struct sta_info *sta,
961				  struct ieee80211_mgmt *mgmt,
962				  size_t len)
963{
964	struct tid_ampdu_tx *tid_tx;
965	struct ieee80211_txq *txq;
966	u16 capab, tid, buf_size;
967	bool amsdu;
968
969	capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
970	amsdu = capab & IEEE80211_ADDBA_PARAM_AMSDU_MASK;
971	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
972	buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
973	buf_size = min(buf_size, local->hw.max_tx_aggregation_subframes);
974
975	txq = sta->sta.txq[tid];
976	if (!amsdu && txq)
977		set_bit(IEEE80211_TXQ_NO_AMSDU, &to_txq_info(txq)->flags);
978
979	mutex_lock(&sta->ampdu_mlme.mtx);
980
981	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
982	if (!tid_tx)
983		goto out;
984
985	if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
986		ht_dbg(sta->sdata, "wrong addBA response token, %pM tid %d\n",
987		       sta->sta.addr, tid);
988		goto out;
989	}
990
991	del_timer_sync(&tid_tx->addba_resp_timer);
992
993	ht_dbg(sta->sdata, "switched off addBA timer for %pM tid %d\n",
994	       sta->sta.addr, tid);
995
996	/*
997	 * addba_resp_timer may have fired before we got here, and
998	 * caused WANT_STOP to be set. If the stop then was already
999	 * processed further, STOPPING might be set.
1000	 */
1001	if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
1002	    test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
1003		ht_dbg(sta->sdata,
1004		       "got addBA resp for %pM tid %d but we already gave up\n",
1005		       sta->sta.addr, tid);
1006		goto out;
1007	}
1008
1009	/*
1010	 * IEEE 802.11-2007 7.3.1.14:
1011	 * In an ADDBA Response frame, when the Status Code field
1012	 * is set to 0, the Buffer Size subfield is set to a value
1013	 * of at least 1.
1014	 */
1015	if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
1016			== WLAN_STATUS_SUCCESS && buf_size) {
1017		if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
1018				     &tid_tx->state)) {
1019			/* ignore duplicate response */
1020			goto out;
1021		}
1022
1023		tid_tx->buf_size = buf_size;
1024		tid_tx->amsdu = amsdu;
1025
1026		if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
1027			ieee80211_agg_tx_operational(local, sta, tid);
1028
1029		sta->ampdu_mlme.addba_req_num[tid] = 0;
1030
1031		tid_tx->timeout =
1032			le16_to_cpu(mgmt->u.action.u.addba_resp.timeout);
1033
1034		if (tid_tx->timeout) {
1035			mod_timer(&tid_tx->session_timer,
1036				  TU_TO_EXP_TIME(tid_tx->timeout));
1037			tid_tx->last_tx = jiffies;
1038		}
1039
1040	} else {
1041		___ieee80211_stop_tx_ba_session(sta, tid, AGG_STOP_DECLINED);
1042	}
1043
1044 out:
1045	mutex_unlock(&sta->ampdu_mlme.mtx);
1046}
1047