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 2007-2009, Intel Corporation
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/ieee80211.h>
  17 #include <net/mac80211.h>
  18 #include "ieee80211_i.h"
  19 #include "driver-ops.h"
  20 #include "wme.h"
  21
  22 /**
  23  * DOC: TX aggregation
  24  *
  25  * Aggregation on the TX side requires setting the hardware flag
  26  * %IEEE80211_HW_AMPDU_AGGREGATION as well as, if present, the @ampdu_queues
  27  * hardware parameter to the number of hardware AMPDU queues. If there are no
  28  * hardware queues then the driver will (currently) have to do all frame
  29  * buffering.
  30  *
  31  * When TX aggregation is started by some subsystem (usually the rate control
  32  * algorithm would be appropriate) by calling the
  33  * ieee80211_start_tx_ba_session() function, the driver will be notified via
  34  * its @ampdu_action function, with the %IEEE80211_AMPDU_TX_START action.
  35  *
  36  * In response to that, the driver is later required to call the
  37  * ieee80211_start_tx_ba_cb() (or ieee80211_start_tx_ba_cb_irqsafe())
  38  * function, which will start the aggregation session.
  39  *
  40  * Similarly, when the aggregation session is stopped by
  41  * ieee80211_stop_tx_ba_session(), the driver's @ampdu_action function will
  42  * be called with the action %IEEE80211_AMPDU_TX_STOP. In this case, the
  43  * call must not fail, and the driver must later call ieee80211_stop_tx_ba_cb()
  44  * (or ieee80211_stop_tx_ba_cb_irqsafe()).
  45  */
  46
  47 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
  48                                          const u8 *da, u16 tid,
  49                                          u8 dialog_token, u16 start_seq_num,
  50                                          u16 agg_size, u16 timeout)
  51 {
  52         struct ieee80211_local *local = sdata->local;
  53         struct sk_buff *skb;
  54         struct ieee80211_mgmt *mgmt;
  55         u16 capab;
  56
  57         skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
  58
  59         if (!skb) {
  60                 printk(KERN_ERR "%s: failed to allocate buffer "
  61                                 "for addba request frame\n", sdata->dev->name);
  62                 return;
  63         }
  64         skb_reserve(skb, local->hw.extra_tx_headroom);
  65         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
  66         memset(mgmt, 0, 24);
  67         memcpy(mgmt->da, da, ETH_ALEN);
  68         memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
  69         if (sdata->vif.type == NL80211_IFTYPE_AP ||
  70             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
  71                 memcpy(mgmt->bssid, sdata->dev->dev_addr, ETH_ALEN);
  72         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
  73                 memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
  74
  75         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  76                                           IEEE80211_STYPE_ACTION);
  77
  78         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
  79
  80         mgmt->u.action.category = WLAN_CATEGORY_BACK;
  81         mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
  82
  83         mgmt->u.action.u.addba_req.dialog_token = dialog_token;
  84         capab = (u16)(1 << 1);          /* bit 1 aggregation policy */
  85         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
  86         capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
  87
  88         mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
  89
  90         mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
  91         mgmt->u.action.u.addba_req.start_seq_num =
  92                                         cpu_to_le16(start_seq_num << 4);
  93
  94         ieee80211_tx_skb(sdata, skb, 1);
  95 }
  96
  97 void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u16 ssn)
  98 {
  99         struct ieee80211_local *local = sdata->local;
 100         struct sk_buff *skb;
 101         struct ieee80211_bar *bar;
 102         u16 bar_control = 0;
 103
 104         skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
 105         if (!skb) {
 106                 printk(KERN_ERR "%s: failed to allocate buffer for "
 107                         "bar frame\n", sdata->dev->name);
 108                 return;
 109         }
 110         skb_reserve(skb, local->hw.extra_tx_headroom);
 111         bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
 112         memset(bar, 0, sizeof(*bar));
 113         bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
 114                                          IEEE80211_STYPE_BACK_REQ);
 115         memcpy(bar->ra, ra, ETH_ALEN);
 116         memcpy(bar->ta, sdata->dev->dev_addr, ETH_ALEN);
 117         bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 118         bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
 119         bar_control |= (u16)(tid << 12);
 120         bar->control = cpu_to_le16(bar_control);
 121         bar->start_seq_num = cpu_to_le16(ssn);
 122
 123         ieee80211_tx_skb(sdata, skb, 0);
 124 }
 125
 126 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 127                                     enum ieee80211_back_parties initiator)
 128 {
 129         struct ieee80211_local *local = sta->local;
 130         int ret;
 131         u8 *state;
 132
 133 #ifdef CONFIG_MAC80211_HT_DEBUG
 134         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 135                sta->sta.addr, tid);
 136 #endif /* CONFIG_MAC80211_HT_DEBUG */
 137
 138         state = &sta->ampdu_mlme.tid_state_tx[tid];
 139
 140         if (*state == HT_AGG_STATE_OPERATIONAL)
 141                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 142
 143         *state = HT_AGG_STATE_REQ_STOP_BA_MSK |
 144                 (initiator << HT_AGG_STATE_INITIATOR_SHIFT);
 145
 146         ret = drv_ampdu_action(local, IEEE80211_AMPDU_TX_STOP,
 147                                &sta->sta, tid, NULL);
 148
 149         /* HW shall not deny going back to legacy */
 150         if (WARN_ON(ret)) {
 151                 /*
 152                  * We may have pending packets get stuck in this case...
 153                  * Not bothering with a workaround for now.
 154                  */
 155         }
 156
 157         return ret;
 158 }
 159
 160 /*
 161  * After sending add Block Ack request we activated a timer until
 162  * add Block Ack response will arrive from the recipient.
 163  * If this timer expires sta_addba_resp_timer_expired will be executed.
 164  */
 165 static void sta_addba_resp_timer_expired(unsigned long data)
 166 {
 167         /* not an elegant detour, but there is no choice as the timer passes
 168          * only one argument, and both sta_info and TID are needed, so init
 169          * flow in sta_info_create gives the TID as data, while the timer_to_id
 170          * array gives the sta through container_of */
 171         u16 tid = *(u8 *)data;
 172         struct sta_info *sta = container_of((void *)data,
 173                 struct sta_info, timer_to_tid[tid]);
 174         u8 *state;
 175
 176         state = &sta->ampdu_mlme.tid_state_tx[tid];
 177
 178         /* check if the TID waits for addBA response */
 179         spin_lock_bh(&sta->lock);
 180         if ((*state & (HT_ADDBA_REQUESTED_MSK | HT_ADDBA_RECEIVED_MSK)) !=
 181                                                 HT_ADDBA_REQUESTED_MSK) {
 182                 spin_unlock_bh(&sta->lock);
 183                 *state = HT_AGG_STATE_IDLE;
 184 #ifdef CONFIG_MAC80211_HT_DEBUG
 185                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 186                                 "(or no longer) expecting addBA response there",
 187                         tid);
 188 #endif
 189                 return;
 190         }
 191
 192 #ifdef CONFIG_MAC80211_HT_DEBUG
 193         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 194 #endif
 195
 196         ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 197         spin_unlock_bh(&sta->lock);
 198 }
 199
 200 static inline int ieee80211_ac_from_tid(int tid)
 201 {
 202         return ieee802_1d_to_ac[tid & 7];
 203 }
 204
 205 int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
 206 {
 207         struct ieee80211_local *local = hw_to_local(hw);
 208         struct sta_info *sta;
 209         struct ieee80211_sub_if_data *sdata;
 210         u8 *state;
 211         int ret = 0;
 212         u16 start_seq_num;
 213
 214         if (WARN_ON(!local->ops->ampdu_action))
 215                 return -EINVAL;
 216
 217         if ((tid >= STA_TID_NUM) || !(hw->flags & IEEE80211_HW_AMPDU_AGGREGATION))
 218                 return -EINVAL;
 219
 220 #ifdef CONFIG_MAC80211_HT_DEBUG
 221         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 222                ra, tid);
 223 #endif /* CONFIG_MAC80211_HT_DEBUG */
 224
 225         rcu_read_lock();
 226
 227         sta = sta_info_get(local, ra);
 228         if (!sta) {
 229 #ifdef CONFIG_MAC80211_HT_DEBUG
 230                 printk(KERN_DEBUG "Could not find the station\n");
 231 #endif
 232                 ret = -ENOENT;
 233                 goto unlock;
 234         }
 235
 236         /*
 237          * The aggregation code is not prepared to handle
 238          * anything but STA/AP due to the BSSID handling.
 239          * IBSS could work in the code but isn't supported
 240          * by drivers or the standard.
 241          */
 242         if (sta->sdata->vif.type != NL80211_IFTYPE_STATION &&
 243             sta->sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 244             sta->sdata->vif.type != NL80211_IFTYPE_AP) {
 245                 ret = -EINVAL;
 246                 goto unlock;
 247         }
 248
 249         if (test_sta_flags(sta, WLAN_STA_SUSPEND)) {
 250 #ifdef CONFIG_MAC80211_HT_DEBUG
 251                 printk(KERN_DEBUG "Suspend in progress. "
 252                        "Denying BA session request\n");
 253 #endif
 254                 ret = -EINVAL;
 255                 goto unlock;
 256         }
 257
 258         spin_lock_bh(&sta->lock);
 259         spin_lock(&local->ampdu_lock);
 260
 261         sdata = sta->sdata;
 262
 263         /* we have tried too many times, receiver does not want A-MPDU */
 264         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 265                 ret = -EBUSY;
 266                 goto err_unlock_sta;
 267         }
 268
 269         state = &sta->ampdu_mlme.tid_state_tx[tid];
 270         /* check if the TID is not in aggregation flow already */
 271         if (*state != HT_AGG_STATE_IDLE) {
 272 #ifdef CONFIG_MAC80211_HT_DEBUG
 273                 printk(KERN_DEBUG "BA request denied - session is not "
 274                                  "idle on tid %u\n", tid);
 275 #endif /* CONFIG_MAC80211_HT_DEBUG */
 276                 ret = -EAGAIN;
 277                 goto err_unlock_sta;
 278         }
 279
 280         /*
 281          * While we're asking the driver about the aggregation,
 282          * stop the AC queue so that we don't have to worry
 283          * about frames that came in while we were doing that,
 284          * which would require us to put them to the AC pending
 285          * afterwards which just makes the code more complex.
 286          */
 287         ieee80211_stop_queue_by_reason(
 288                 &local->hw, ieee80211_ac_from_tid(tid),
 289                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 290
 291         /* prepare A-MPDU MLME for Tx aggregation */
 292         sta->ampdu_mlme.tid_tx[tid] =
 293                         kmalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 294         if (!sta->ampdu_mlme.tid_tx[tid]) {
 295 #ifdef CONFIG_MAC80211_HT_DEBUG
 296                 if (net_ratelimit())
 297                         printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
 298                                         tid);
 299 #endif
 300                 ret = -ENOMEM;
 301                 goto err_wake_queue;
 302         }
 303
 304         skb_queue_head_init(&sta->ampdu_mlme.tid_tx[tid]->pending);
 305
 306         /* Tx timer */
 307         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.function =
 308                         sta_addba_resp_timer_expired;
 309         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.data =
 310                         (unsigned long)&sta->timer_to_tid[tid];
 311         init_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 312
 313         /* Ok, the Addba frame hasn't been sent yet, but if the driver calls the
 314          * call back right away, it must see that the flow has begun */
 315         *state |= HT_ADDBA_REQUESTED_MSK;
 316
 317         start_seq_num = sta->tid_seq[tid];
 318
 319         ret = drv_ampdu_action(local, IEEE80211_AMPDU_TX_START,
 320                                &sta->sta, tid, &start_seq_num);
 321
 322         if (ret) {
 323 #ifdef CONFIG_MAC80211_HT_DEBUG
 324                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 325                                         " tid %d\n", tid);
 326 #endif /* CONFIG_MAC80211_HT_DEBUG */
 327                 *state = HT_AGG_STATE_IDLE;
 328                 goto err_free;
 329         }
 330
 331         /* Driver vetoed or OKed, but we can take packets again now */
 332         ieee80211_wake_queue_by_reason(
 333                 &local->hw, ieee80211_ac_from_tid(tid),
 334                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 335
 336         spin_unlock(&local->ampdu_lock);
 337         spin_unlock_bh(&sta->lock);
 338
 339         /* send an addBA request */
 340         sta->ampdu_mlme.dialog_token_allocator++;
 341         sta->ampdu_mlme.tid_tx[tid]->dialog_token =
 342                         sta->ampdu_mlme.dialog_token_allocator;
 343         sta->ampdu_mlme.tid_tx[tid]->ssn = start_seq_num;
 344
 345         ieee80211_send_addba_request(sta->sdata, ra, tid,
 346                          sta->ampdu_mlme.tid_tx[tid]->dialog_token,
 347                          sta->ampdu_mlme.tid_tx[tid]->ssn,
 348                          0x40, 5000);
 349         sta->ampdu_mlme.addba_req_num[tid]++;
 350         /* activate the timer for the recipient's addBA response */
 351         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
 352                                 jiffies + ADDBA_RESP_INTERVAL;
 353         add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 354 #ifdef CONFIG_MAC80211_HT_DEBUG
 355         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 356 #endif
 357         goto unlock;
 358
 359  err_free:
 360         kfree(sta->ampdu_mlme.tid_tx[tid]);
 361         sta->ampdu_mlme.tid_tx[tid] = NULL;
 362  err_wake_queue:
 363         ieee80211_wake_queue_by_reason(
 364                 &local->hw, ieee80211_ac_from_tid(tid),
 365                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 366  err_unlock_sta:
 367         spin_unlock(&local->ampdu_lock);
 368         spin_unlock_bh(&sta->lock);
 369  unlock:
 370         rcu_read_unlock();
 371         return ret;
 372 }
 373 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 374
 375 /*
 376  * splice packets from the STA's pending to the local pending,
 377  * requires a call to ieee80211_agg_splice_finish and holding
 378  * local->ampdu_lock across both calls.
 379  */
 380 static void ieee80211_agg_splice_packets(struct ieee80211_local *local,
 381                                          struct sta_info *sta, u16 tid)
 382 {
 383         unsigned long flags;
 384         u16 queue = ieee80211_ac_from_tid(tid);
 385
 386         ieee80211_stop_queue_by_reason(
 387                 &local->hw, queue,
 388                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 389
 390         if (!(sta->ampdu_mlme.tid_state_tx[tid] & HT_ADDBA_REQUESTED_MSK))
 391                 return;
 392
 393         if (WARN(!sta->ampdu_mlme.tid_tx[tid],
 394                  "TID %d gone but expected when splicing aggregates from"
 395                  "the pending queue\n", tid))
 396                 return;
 397
 398         if (!skb_queue_empty(&sta->ampdu_mlme.tid_tx[tid]->pending)) {
 399                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 400                 /* copy over remaining packets */
 401                 skb_queue_splice_tail_init(
 402                         &sta->ampdu_mlme.tid_tx[tid]->pending,
 403                         &local->pending[queue]);
 404                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 405         }
 406 }
 407
 408 static void ieee80211_agg_splice_finish(struct ieee80211_local *local,
 409                                         struct sta_info *sta, u16 tid)
 410 {
 411         u16 queue = ieee80211_ac_from_tid(tid);
 412
 413         ieee80211_wake_queue_by_reason(
 414                 &local->hw, queue,
 415                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 416 }
 417
 418 /* caller must hold sta->lock */
 419 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 420                                          struct sta_info *sta, u16 tid)
 421 {
 422 #ifdef CONFIG_MAC80211_HT_DEBUG
 423         printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
 424 #endif
 425
 426         spin_lock(&local->ampdu_lock);
 427         ieee80211_agg_splice_packets(local, sta, tid);
 428         /*
 429          * NB: we rely on sta->lock being taken in the TX
 430          * processing here when adding to the pending queue,
 431          * otherwise we could only change the state of the
 432          * session to OPERATIONAL _here_.
 433          */
 434         ieee80211_agg_splice_finish(local, sta, tid);
 435         spin_unlock(&local->ampdu_lock);
 436
 437         drv_ampdu_action(local, IEEE80211_AMPDU_TX_OPERATIONAL,
 438                          &sta->sta, tid, NULL);
 439 }
 440
 441 void ieee80211_start_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u16 tid)
 442 {
 443         struct ieee80211_local *local = hw_to_local(hw);
 444         struct sta_info *sta;
 445         u8 *state;
 446
 447         if (tid >= STA_TID_NUM) {
 448 #ifdef CONFIG_MAC80211_HT_DEBUG
 449                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 450                                 tid, STA_TID_NUM);
 451 #endif
 452                 return;
 453         }
 454
 455         rcu_read_lock();
 456         sta = sta_info_get(local, ra);
 457         if (!sta) {
 458                 rcu_read_unlock();
 459 #ifdef CONFIG_MAC80211_HT_DEBUG
 460                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 461 #endif
 462                 return;
 463         }
 464
 465         state = &sta->ampdu_mlme.tid_state_tx[tid];
 466         spin_lock_bh(&sta->lock);
 467
 468         if (WARN_ON(!(*state & HT_ADDBA_REQUESTED_MSK))) {
 469 #ifdef CONFIG_MAC80211_HT_DEBUG
 470                 printk(KERN_DEBUG "addBA was not requested yet, state is %d\n",
 471                                 *state);
 472 #endif
 473                 spin_unlock_bh(&sta->lock);
 474                 rcu_read_unlock();
 475                 return;
 476         }
 477
 478         if (WARN_ON(*state & HT_ADDBA_DRV_READY_MSK))
 479                 goto out;
 480
 481         *state |= HT_ADDBA_DRV_READY_MSK;
 482
 483         if (*state == HT_AGG_STATE_OPERATIONAL)
 484                 ieee80211_agg_tx_operational(local, sta, tid);
 485
 486  out:
 487         spin_unlock_bh(&sta->lock);
 488         rcu_read_unlock();
 489 }
 490 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb);
 491
 492 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
 493                                       const u8 *ra, u16 tid)
 494 {
 495         struct ieee80211_local *local = hw_to_local(hw);
 496         struct ieee80211_ra_tid *ra_tid;
 497         struct sk_buff *skb = dev_alloc_skb(0);
 498
 499         if (unlikely(!skb)) {
 500 #ifdef CONFIG_MAC80211_HT_DEBUG
 501                 if (net_ratelimit())
 502                         printk(KERN_WARNING "%s: Not enough memory, "
 503                                "dropping start BA session", skb->dev->name);
 504 #endif
 505                 return;
 506         }
 507         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 508         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 509         ra_tid->tid = tid;
 510
 511         skb->pkt_type = IEEE80211_ADDBA_MSG;
 512         skb_queue_tail(&local->skb_queue, skb);
 513         tasklet_schedule(&local->tasklet);
 514 }
 515 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 516
 517 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 518                                    enum ieee80211_back_parties initiator)
 519 {
 520         u8 *state;
 521         int ret;
 522
 523         /* check if the TID is in aggregation */
 524         state = &sta->ampdu_mlme.tid_state_tx[tid];
 525         spin_lock_bh(&sta->lock);
 526
 527         if (*state != HT_AGG_STATE_OPERATIONAL) {
 528                 ret = -ENOENT;
 529                 goto unlock;
 530         }
 531
 532         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator);
 533
 534  unlock:
 535         spin_unlock_bh(&sta->lock);
 536         return ret;
 537 }
 538
 539 int ieee80211_stop_tx_ba_session(struct ieee80211_hw *hw,
 540                                  u8 *ra, u16 tid,
 541                                  enum ieee80211_back_parties initiator)
 542 {
 543         struct ieee80211_local *local = hw_to_local(hw);
 544         struct sta_info *sta;
 545         int ret = 0;
 546
 547         if (!local->ops->ampdu_action)
 548                 return -EINVAL;
 549
 550         if (tid >= STA_TID_NUM)
 551                 return -EINVAL;
 552
 553         rcu_read_lock();
 554         sta = sta_info_get(local, ra);
 555         if (!sta) {
 556                 rcu_read_unlock();
 557                 return -ENOENT;
 558         }
 559
 560         ret = __ieee80211_stop_tx_ba_session(sta, tid, initiator);
 561         rcu_read_unlock();
 562         return ret;
 563 }
 564 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 565
 566 void ieee80211_stop_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u8 tid)
 567 {
 568         struct ieee80211_local *local = hw_to_local(hw);
 569         struct sta_info *sta;
 570         u8 *state;
 571
 572         if (tid >= STA_TID_NUM) {
 573 #ifdef CONFIG_MAC80211_HT_DEBUG
 574                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 575                                 tid, STA_TID_NUM);
 576 #endif
 577                 return;
 578         }
 579
 580 #ifdef CONFIG_MAC80211_HT_DEBUG
 581         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 582                ra, tid);
 583 #endif /* CONFIG_MAC80211_HT_DEBUG */
 584
 585         rcu_read_lock();
 586         sta = sta_info_get(local, ra);
 587         if (!sta) {
 588 #ifdef CONFIG_MAC80211_HT_DEBUG
 589                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 590 #endif
 591                 rcu_read_unlock();
 592                 return;
 593         }
 594         state = &sta->ampdu_mlme.tid_state_tx[tid];
 595
 596         /* NOTE: no need to use sta->lock in this state check, as
 597          * ieee80211_stop_tx_ba_session will let only one stop call to
 598          * pass through per sta/tid
 599          */
 600         if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) {
 601 #ifdef CONFIG_MAC80211_HT_DEBUG
 602                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 603 #endif
 604                 rcu_read_unlock();
 605                 return;
 606         }
 607
 608         if (*state & HT_AGG_STATE_INITIATOR_MSK)
 609                 ieee80211_send_delba(sta->sdata, ra, tid,
 610                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 611
 612         spin_lock_bh(&sta->lock);
 613         spin_lock(&local->ampdu_lock);
 614
 615         ieee80211_agg_splice_packets(local, sta, tid);
 616
 617         *state = HT_AGG_STATE_IDLE;
 618         /* from now on packets are no longer put onto sta->pending */
 619         kfree(sta->ampdu_mlme.tid_tx[tid]);
 620         sta->ampdu_mlme.tid_tx[tid] = NULL;
 621
 622         ieee80211_agg_splice_finish(local, sta, tid);
 623
 624         spin_unlock(&local->ampdu_lock);
 625         spin_unlock_bh(&sta->lock);
 626
 627         rcu_read_unlock();
 628 }
 629 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb);
 630
 631 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
 632                                      const u8 *ra, u16 tid)
 633 {
 634         struct ieee80211_local *local = hw_to_local(hw);
 635         struct ieee80211_ra_tid *ra_tid;
 636         struct sk_buff *skb = dev_alloc_skb(0);
 637
 638         if (unlikely(!skb)) {
 639 #ifdef CONFIG_MAC80211_HT_DEBUG
 640                 if (net_ratelimit())
 641                         printk(KERN_WARNING "%s: Not enough memory, "
 642                                "dropping stop BA session", skb->dev->name);
 643 #endif
 644                 return;
 645         }
 646         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 647         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 648         ra_tid->tid = tid;
 649
 650         skb->pkt_type = IEEE80211_DELBA_MSG;
 651         skb_queue_tail(&local->skb_queue, skb);
 652         tasklet_schedule(&local->tasklet);
 653 }
 654 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 655
 656
 657 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 658                                   struct sta_info *sta,
 659                                   struct ieee80211_mgmt *mgmt,
 660                                   size_t len)
 661 {
 662         u16 capab, tid;
 663         u8 *state;
 664
 665         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 666         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 667
 668         state = &sta->ampdu_mlme.tid_state_tx[tid];
 669
 670         spin_lock_bh(&sta->lock);
 671
 672         if (!(*state & HT_ADDBA_REQUESTED_MSK))
 673                 goto out;
 674
 675         if (mgmt->u.action.u.addba_resp.dialog_token !=
 676                 sta->ampdu_mlme.tid_tx[tid]->dialog_token) {
 677 #ifdef CONFIG_MAC80211_HT_DEBUG
 678                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 679 #endif /* CONFIG_MAC80211_HT_DEBUG */
 680                 goto out;
 681         }
 682
 683         del_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 684
 685 #ifdef CONFIG_MAC80211_HT_DEBUG
 686         printk(KERN_DEBUG "switched off addBA timer for tid %d \n", tid);
 687 #endif /* CONFIG_MAC80211_HT_DEBUG */
 688
 689         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 690                         == WLAN_STATUS_SUCCESS) {
 691                 u8 curstate = *state;
 692
 693                 *state |= HT_ADDBA_RECEIVED_MSK;
 694
 695                 if (*state != curstate && *state == HT_AGG_STATE_OPERATIONAL)
 696                         ieee80211_agg_tx_operational(local, sta, tid);
 697
 698                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 699         } else {
 700                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 701         }
 702
 703  out:
 704         spin_unlock_bh(&sta->lock);
 705 }