net/mac80211/agg-tx.c

   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  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/ieee80211.h>
  17 #include <linux/slab.h>
  18 #include <net/mac80211.h>
  19 #include "ieee80211_i.h"
  20 #include "driver-ops.h"
  21 #include "wme.h"
  22
  23 /**
  24  * DOC: TX 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  */
  58
  59 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
  60                                          const u8 *da, u16 tid,
  61                                          u8 dialog_token, u16 start_seq_num,
  62                                          u16 agg_size, u16 timeout)
  63 {
  64         struct ieee80211_local *local = sdata->local;
  65         struct sk_buff *skb;
  66         struct ieee80211_mgmt *mgmt;
  67         u16 capab;
  68
  69         skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
  70
  71         if (!skb) {
  72                 printk(KERN_ERR "%s: failed to allocate buffer "
  73                                 "for addba request frame\n", sdata->name);
  74                 return;
  75         }
  76         skb_reserve(skb, local->hw.extra_tx_headroom);
  77         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
  78         memset(mgmt, 0, 24);
  79         memcpy(mgmt->da, da, ETH_ALEN);
  80         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
  81         if (sdata->vif.type == NL80211_IFTYPE_AP ||
  82             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
  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
  87         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  88                                           IEEE80211_STYPE_ACTION);
  89
  90         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
  91
  92         mgmt->u.action.category = WLAN_CATEGORY_BACK;
  93         mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
  94
  95         mgmt->u.action.u.addba_req.dialog_token = dialog_token;
  96         capab = (u16)(1 << 1);          /* bit 1 aggregation policy */
  97         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
  98         capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
  99
 100         mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
 101
 102         mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
 103         mgmt->u.action.u.addba_req.start_seq_num =
 104                                         cpu_to_le16(start_seq_num << 4);
 105
 106         ieee80211_tx_skb(sdata, skb);
 107 }
 108
 109 void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u16 ssn)
 110 {
 111         struct ieee80211_local *local = sdata->local;
 112         struct sk_buff *skb;
 113         struct ieee80211_bar *bar;
 114         u16 bar_control = 0;
 115
 116         skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
 117         if (!skb) {
 118                 printk(KERN_ERR "%s: failed to allocate buffer for "
 119                         "bar frame\n", sdata->name);
 120                 return;
 121         }
 122         skb_reserve(skb, local->hw.extra_tx_headroom);
 123         bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
 124         memset(bar, 0, sizeof(*bar));
 125         bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
 126                                          IEEE80211_STYPE_BACK_REQ);
 127         memcpy(bar->ra, ra, ETH_ALEN);
 128         memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
 129         bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 130         bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
 131         bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
 132         bar->control = cpu_to_le16(bar_control);
 133         bar->start_seq_num = cpu_to_le16(ssn);
 134
 135         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 136         ieee80211_tx_skb(sdata, skb);
 137 }
 138
 139 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
 140                              struct tid_ampdu_tx *tid_tx)
 141 {
 142         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 143         lockdep_assert_held(&sta->lock);
 144         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 145 }
 146
 147 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 148                                     enum ieee80211_back_parties initiator,
 149                                     bool tx)
 150 {
 151         struct ieee80211_local *local = sta->local;
 152         struct tid_ampdu_tx *tid_tx;
 153         int ret;
 154
 155         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 156
 157         spin_lock_bh(&sta->lock);
 158
 159         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 160         if (!tid_tx) {
 161                 spin_unlock_bh(&sta->lock);
 162                 return -ENOENT;
 163         }
 164
 165         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 166                 /* not even started yet! */
 167                 ieee80211_assign_tid_tx(sta, tid, NULL);
 168                 spin_unlock_bh(&sta->lock);
 169                 kfree_rcu(tid_tx, rcu_head);
 170                 return 0;
 171         }
 172
 173         spin_unlock_bh(&sta->lock);
 174
 175 #ifdef CONFIG_MAC80211_HT_DEBUG
 176         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 177                sta->sta.addr, tid);
 178 #endif /* CONFIG_MAC80211_HT_DEBUG */
 179
 180         set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 181
 182         del_timer_sync(&tid_tx->addba_resp_timer);
 183
 184         /*
 185          * After this packets are no longer handed right through
 186          * to the driver but are put onto tid_tx->pending instead,
 187          * with locking to ensure proper access.
 188          */
 189         clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 190
 191         tid_tx->stop_initiator = initiator;
 192         tid_tx->tx_stop = tx;
 193
 194         ret = drv_ampdu_action(local, sta->sdata,
 195                                IEEE80211_AMPDU_TX_STOP,
 196                                &sta->sta, tid, NULL, 0);
 197
 198         /* HW shall not deny going back to legacy */
 199         if (WARN_ON(ret)) {
 200                 /*
 201                  * We may have pending packets get stuck in this case...
 202                  * Not bothering with a workaround for now.
 203                  */
 204         }
 205
 206         return ret;
 207 }
 208
 209 /*
 210  * After sending add Block Ack request we activated a timer until
 211  * add Block Ack response will arrive from the recipient.
 212  * If this timer expires sta_addba_resp_timer_expired will be executed.
 213  */
 214 static void sta_addba_resp_timer_expired(unsigned long data)
 215 {
 216         /* not an elegant detour, but there is no choice as the timer passes
 217          * only one argument, and both sta_info and TID are needed, so init
 218          * flow in sta_info_create gives the TID as data, while the timer_to_id
 219          * array gives the sta through container_of */
 220         u16 tid = *(u8 *)data;
 221         struct sta_info *sta = container_of((void *)data,
 222                 struct sta_info, timer_to_tid[tid]);
 223         struct tid_ampdu_tx *tid_tx;
 224
 225         /* check if the TID waits for addBA response */
 226         rcu_read_lock();
 227         tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 228         if (!tid_tx ||
 229             test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 230                 rcu_read_unlock();
 231 #ifdef CONFIG_MAC80211_HT_DEBUG
 232                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 233                                 "(or no longer) expecting addBA response there\n",
 234                         tid);
 235 #endif
 236                 return;
 237         }
 238
 239 #ifdef CONFIG_MAC80211_HT_DEBUG
 240         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 241 #endif
 242
 243         ieee80211_stop_tx_ba_session(&sta->sta, tid);
 244         rcu_read_unlock();
 245 }
 246
 247 static inline int ieee80211_ac_from_tid(int tid)
 248 {
 249         return ieee802_1d_to_ac[tid & 7];
 250 }
 251
 252 /*
 253  * When multiple aggregation sessions on multiple stations
 254  * are being created/destroyed simultaneously, we need to
 255  * refcount the global queue stop caused by that in order
 256  * to not get into a situation where one of the aggregation
 257  * setup or teardown re-enables queues before the other is
 258  * ready to handle that.
 259  *
 260  * These two functions take care of this issue by keeping
 261  * a global "agg_queue_stop" refcount.
 262  */
 263 static void __acquires(agg_queue)
 264 ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
 265 {
 266         int queue = ieee80211_ac_from_tid(tid);
 267
 268         if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
 269                 ieee80211_stop_queue_by_reason(
 270                         &local->hw, queue,
 271                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 272         __acquire(agg_queue);
 273 }
 274
 275 static void __releases(agg_queue)
 276 ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 277 {
 278         int queue = ieee80211_ac_from_tid(tid);
 279
 280         if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
 281                 ieee80211_wake_queue_by_reason(
 282                         &local->hw, queue,
 283                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 284         __release(agg_queue);
 285 }
 286
 287 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 288 {
 289         struct tid_ampdu_tx *tid_tx;
 290         struct ieee80211_local *local = sta->local;
 291         struct ieee80211_sub_if_data *sdata = sta->sdata;
 292         u16 start_seq_num;
 293         int ret;
 294
 295         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 296
 297         /*
 298          * While we're asking the driver about the aggregation,
 299          * stop the AC queue so that we don't have to worry
 300          * about frames that came in while we were doing that,
 301          * which would require us to put them to the AC pending
 302          * afterwards which just makes the code more complex.
 303          */
 304         ieee80211_stop_queue_agg(local, tid);
 305
 306         clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 307
 308         /*
 309          * make sure no packets are being processed to get
 310          * valid starting sequence number
 311          */
 312         synchronize_net();
 313
 314         start_seq_num = sta->tid_seq[tid] >> 4;
 315
 316         ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 317                                &sta->sta, tid, &start_seq_num, 0);
 318         if (ret) {
 319 #ifdef CONFIG_MAC80211_HT_DEBUG
 320                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 321                                         " tid %d\n", tid);
 322 #endif
 323                 spin_lock_bh(&sta->lock);
 324                 ieee80211_assign_tid_tx(sta, tid, NULL);
 325                 spin_unlock_bh(&sta->lock);
 326
 327                 ieee80211_wake_queue_agg(local, tid);
 328                 kfree_rcu(tid_tx, rcu_head);
 329                 return;
 330         }
 331
 332         /* we can take packets again now */
 333         ieee80211_wake_queue_agg(local, tid);
 334
 335         /* activate the timer for the recipient's addBA response */
 336         mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 337 #ifdef CONFIG_MAC80211_HT_DEBUG
 338         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 339 #endif
 340
 341         spin_lock_bh(&sta->lock);
 342         sta->ampdu_mlme.addba_req_num[tid]++;
 343         spin_unlock_bh(&sta->lock);
 344
 345         /* send AddBA request */
 346         ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 347                                      tid_tx->dialog_token, start_seq_num,
 348                                      local->hw.max_tx_aggregation_subframes,
 349                                      tid_tx->timeout);
 350 }
 351
 352 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 353                                   u16 timeout)
 354 {
 355         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 356         struct ieee80211_sub_if_data *sdata = sta->sdata;
 357         struct ieee80211_local *local = sdata->local;
 358         struct tid_ampdu_tx *tid_tx;
 359         int ret = 0;
 360
 361         trace_api_start_tx_ba_session(pubsta, tid);
 362
 363         if (WARN_ON(!local->ops->ampdu_action))
 364                 return -EINVAL;
 365
 366         if ((tid >= STA_TID_NUM) ||
 367             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION))
 368                 return -EINVAL;
 369
 370 #ifdef CONFIG_MAC80211_HT_DEBUG
 371         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 372                pubsta->addr, tid);
 373 #endif /* CONFIG_MAC80211_HT_DEBUG */
 374
 375         /*
 376          * The aggregation code is not prepared to handle
 377          * anything but STA/AP due to the BSSID handling.
 378          * IBSS could work in the code but isn't supported
 379          * by drivers or the standard.
 380          */
 381         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 382             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 383             sdata->vif.type != NL80211_IFTYPE_AP)
 384                 return -EINVAL;
 385
 386         if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
 387 #ifdef CONFIG_MAC80211_HT_DEBUG
 388                 printk(KERN_DEBUG "BA sessions blocked. "
 389                        "Denying BA session request\n");
 390 #endif
 391                 return -EINVAL;
 392         }
 393
 394         spin_lock_bh(&sta->lock);
 395
 396         /* we have tried too many times, receiver does not want A-MPDU */
 397         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 398                 ret = -EBUSY;
 399                 goto err_unlock_sta;
 400         }
 401
 402         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 403         /* check if the TID is not in aggregation flow already */
 404         if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
 405 #ifdef CONFIG_MAC80211_HT_DEBUG
 406                 printk(KERN_DEBUG "BA request denied - session is not "
 407                                  "idle on tid %u\n", tid);
 408 #endif /* CONFIG_MAC80211_HT_DEBUG */
 409                 ret = -EAGAIN;
 410                 goto err_unlock_sta;
 411         }
 412
 413         /* prepare A-MPDU MLME for Tx aggregation */
 414         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 415         if (!tid_tx) {
 416 #ifdef CONFIG_MAC80211_HT_DEBUG
 417                 if (net_ratelimit())
 418                         printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
 419                                         tid);
 420 #endif
 421                 ret = -ENOMEM;
 422                 goto err_unlock_sta;
 423         }
 424
 425         skb_queue_head_init(&tid_tx->pending);
 426         __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 427
 428         tid_tx->timeout = timeout;
 429
 430         /* Tx timer */
 431         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 432         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 433         init_timer(&tid_tx->addba_resp_timer);
 434
 435         /* assign a dialog token */
 436         sta->ampdu_mlme.dialog_token_allocator++;
 437         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 438
 439         /*
 440          * Finally, assign it to the start array; the work item will
 441          * collect it and move it to the normal array.
 442          */
 443         sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
 444
 445         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 446
 447         /* this flow continues off the work */
 448  err_unlock_sta:
 449         spin_unlock_bh(&sta->lock);
 450         return ret;
 451 }
 452 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 453
 454 /*
 455  * splice packets from the STA's pending to the local pending,
 456  * requires a call to ieee80211_agg_splice_finish later
 457  */
 458 static void __acquires(agg_queue)
 459 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 460                              struct tid_ampdu_tx *tid_tx, u16 tid)
 461 {
 462         int queue = ieee80211_ac_from_tid(tid);
 463         unsigned long flags;
 464
 465         ieee80211_stop_queue_agg(local, tid);
 466
 467         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 468                           " from the pending queue\n", tid))
 469                 return;
 470
 471         if (!skb_queue_empty(&tid_tx->pending)) {
 472                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 473                 /* copy over remaining packets */
 474                 skb_queue_splice_tail_init(&tid_tx->pending,
 475                                            &local->pending[queue]);
 476                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 477         }
 478 }
 479
 480 static void __releases(agg_queue)
 481 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 482 {
 483         ieee80211_wake_queue_agg(local, tid);
 484 }
 485
 486 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 487                                          struct sta_info *sta, u16 tid)
 488 {
 489         struct tid_ampdu_tx *tid_tx;
 490
 491         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 492
 493         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 494
 495 #ifdef CONFIG_MAC80211_HT_DEBUG
 496         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 497 #endif
 498
 499         drv_ampdu_action(local, sta->sdata,
 500                          IEEE80211_AMPDU_TX_OPERATIONAL,
 501                          &sta->sta, tid, NULL, tid_tx->buf_size);
 502
 503         /*
 504          * synchronize with TX path, while splicing the TX path
 505          * should block so it won't put more packets onto pending.
 506          */
 507         spin_lock_bh(&sta->lock);
 508
 509         ieee80211_agg_splice_packets(local, tid_tx, tid);
 510         /*
 511          * Now mark as operational. This will be visible
 512          * in the TX path, and lets it go lock-free in
 513          * the common case.
 514          */
 515         set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 516         ieee80211_agg_splice_finish(local, tid);
 517
 518         spin_unlock_bh(&sta->lock);
 519 }
 520
 521 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 522 {
 523         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 524         struct ieee80211_local *local = sdata->local;
 525         struct sta_info *sta;
 526         struct tid_ampdu_tx *tid_tx;
 527
 528         trace_api_start_tx_ba_cb(sdata, ra, tid);
 529
 530         if (tid >= STA_TID_NUM) {
 531 #ifdef CONFIG_MAC80211_HT_DEBUG
 532                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 533                                 tid, STA_TID_NUM);
 534 #endif
 535                 return;
 536         }
 537
 538         mutex_lock(&local->sta_mtx);
 539         sta = sta_info_get(sdata, ra);
 540         if (!sta) {
 541                 mutex_unlock(&local->sta_mtx);
 542 #ifdef CONFIG_MAC80211_HT_DEBUG
 543                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 544 #endif
 545                 return;
 546         }
 547
 548         mutex_lock(&sta->ampdu_mlme.mtx);
 549         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 550
 551         if (WARN_ON(!tid_tx)) {
 552 #ifdef CONFIG_MAC80211_HT_DEBUG
 553                 printk(KERN_DEBUG "addBA was not requested!\n");
 554 #endif
 555                 goto unlock;
 556         }
 557
 558         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 559                 goto unlock;
 560
 561         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 562                 ieee80211_agg_tx_operational(local, sta, tid);
 563
 564  unlock:
 565         mutex_unlock(&sta->ampdu_mlme.mtx);
 566         mutex_unlock(&local->sta_mtx);
 567 }
 568
 569 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 570                                       const u8 *ra, u16 tid)
 571 {
 572         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 573         struct ieee80211_local *local = sdata->local;
 574         struct ieee80211_ra_tid *ra_tid;
 575         struct sk_buff *skb = dev_alloc_skb(0);
 576
 577         if (unlikely(!skb)) {
 578 #ifdef CONFIG_MAC80211_HT_DEBUG
 579                 if (net_ratelimit())
 580                         printk(KERN_WARNING "%s: Not enough memory, "
 581                                "dropping start BA session", sdata->name);
 582 #endif
 583                 return;
 584         }
 585         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 586         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 587         ra_tid->tid = tid;
 588
 589         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 590         skb_queue_tail(&sdata->skb_queue, skb);
 591         ieee80211_queue_work(&local->hw, &sdata->work);
 592 }
 593 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 594
 595 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 596                                    enum ieee80211_back_parties initiator,
 597                                    bool tx)
 598 {
 599         int ret;
 600
 601         mutex_lock(&sta->ampdu_mlme.mtx);
 602
 603         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator, tx);
 604
 605         mutex_unlock(&sta->ampdu_mlme.mtx);
 606
 607         return ret;
 608 }
 609
 610 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 611 {
 612         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 613         struct ieee80211_sub_if_data *sdata = sta->sdata;
 614         struct ieee80211_local *local = sdata->local;
 615         struct tid_ampdu_tx *tid_tx;
 616         int ret = 0;
 617
 618         trace_api_stop_tx_ba_session(pubsta, tid);
 619
 620         if (!local->ops->ampdu_action)
 621                 return -EINVAL;
 622
 623         if (tid >= STA_TID_NUM)
 624                 return -EINVAL;
 625
 626         spin_lock_bh(&sta->lock);
 627         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 628
 629         if (!tid_tx) {
 630                 ret = -ENOENT;
 631                 goto unlock;
 632         }
 633
 634         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 635                 /* already in progress stopping it */
 636                 ret = 0;
 637                 goto unlock;
 638         }
 639
 640         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 641         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 642
 643  unlock:
 644         spin_unlock_bh(&sta->lock);
 645         return ret;
 646 }
 647 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 648
 649 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 650 {
 651         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 652         struct ieee80211_local *local = sdata->local;
 653         struct sta_info *sta;
 654         struct tid_ampdu_tx *tid_tx;
 655
 656         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 657
 658         if (tid >= STA_TID_NUM) {
 659 #ifdef CONFIG_MAC80211_HT_DEBUG
 660                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 661                                 tid, STA_TID_NUM);
 662 #endif
 663                 return;
 664         }
 665
 666 #ifdef CONFIG_MAC80211_HT_DEBUG
 667         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 668                ra, tid);
 669 #endif /* CONFIG_MAC80211_HT_DEBUG */
 670
 671         mutex_lock(&local->sta_mtx);
 672
 673         sta = sta_info_get(sdata, ra);
 674         if (!sta) {
 675 #ifdef CONFIG_MAC80211_HT_DEBUG
 676                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 677 #endif
 678                 goto unlock;
 679         }
 680
 681         mutex_lock(&sta->ampdu_mlme.mtx);
 682         spin_lock_bh(&sta->lock);
 683         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 684
 685         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 686 #ifdef CONFIG_MAC80211_HT_DEBUG
 687                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 688 #endif
 689                 goto unlock_sta;
 690         }
 691
 692         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 693                 ieee80211_send_delba(sta->sdata, ra, tid,
 694                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 695
 696         /*
 697          * When we get here, the TX path will not be lockless any more wrt.
 698          * aggregation, since the OPERATIONAL bit has long been cleared.
 699          * Thus it will block on getting the lock, if it occurs. So if we
 700          * stop the queue now, we will not get any more packets, and any
 701          * that might be being processed will wait for us here, thereby
 702          * guaranteeing that no packets go to the tid_tx pending queue any
 703          * more.
 704          */
 705
 706         ieee80211_agg_splice_packets(local, tid_tx, tid);
 707
 708         /* future packets must not find the tid_tx struct any more */
 709         ieee80211_assign_tid_tx(sta, tid, NULL);
 710
 711         ieee80211_agg_splice_finish(local, tid);
 712
 713         kfree_rcu(tid_tx, rcu_head);
 714
 715  unlock_sta:
 716         spin_unlock_bh(&sta->lock);
 717         mutex_unlock(&sta->ampdu_mlme.mtx);
 718  unlock:
 719         mutex_unlock(&local->sta_mtx);
 720 }
 721
 722 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 723                                      const u8 *ra, u16 tid)
 724 {
 725         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 726         struct ieee80211_local *local = sdata->local;
 727         struct ieee80211_ra_tid *ra_tid;
 728         struct sk_buff *skb = dev_alloc_skb(0);
 729
 730         if (unlikely(!skb)) {
 731 #ifdef CONFIG_MAC80211_HT_DEBUG
 732                 if (net_ratelimit())
 733                         printk(KERN_WARNING "%s: Not enough memory, "
 734                                "dropping stop BA session", sdata->name);
 735 #endif
 736                 return;
 737         }
 738         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 739         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 740         ra_tid->tid = tid;
 741
 742         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 743         skb_queue_tail(&sdata->skb_queue, skb);
 744         ieee80211_queue_work(&local->hw, &sdata->work);
 745 }
 746 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 747
 748
 749 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 750                                   struct sta_info *sta,
 751                                   struct ieee80211_mgmt *mgmt,
 752                                   size_t len)
 753 {
 754         struct tid_ampdu_tx *tid_tx;
 755         u16 capab, tid;
 756         u8 buf_size;
 757
 758         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 759         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 760         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 761
 762         mutex_lock(&sta->ampdu_mlme.mtx);
 763
 764         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 765         if (!tid_tx)
 766                 goto out;
 767
 768         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 769 #ifdef CONFIG_MAC80211_HT_DEBUG
 770                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 771 #endif
 772                 goto out;
 773         }
 774
 775         del_timer(&tid_tx->addba_resp_timer);
 776
 777 #ifdef CONFIG_MAC80211_HT_DEBUG
 778         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 779 #endif
 780         /*
 781          * IEEE 802.11-2007 7.3.1.14:
 782          * In an ADDBA Response frame, when the Status Code field
 783          * is set to 0, the Buffer Size subfield is set to a value
 784          * of at least 1.
 785          */
 786         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 787                         == WLAN_STATUS_SUCCESS && buf_size) {
 788                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 789                                      &tid_tx->state)) {
 790                         /* ignore duplicate response */
 791                         goto out;
 792                 }
 793
 794                 tid_tx->buf_size = buf_size;
 795
 796                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 797                         ieee80211_agg_tx_operational(local, sta, tid);
 798
 799                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 800         } else {
 801                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
 802                                                 true);
 803         }
 804
 805  out:
 806         mutex_unlock(&sta->ampdu_mlme.mtx);
 807 }