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)) {
 181                 spin_unlock_bh(&sta->lock);
 182                 *state = HT_AGG_STATE_IDLE;
 183 #ifdef CONFIG_MAC80211_HT_DEBUG
 184                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 185                                 "expecting addBA response there", tid);
 186 #endif
 187                 return;
 188         }
 189
 190 #ifdef CONFIG_MAC80211_HT_DEBUG
 191         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 192 #endif
 193
 194         ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 195         spin_unlock_bh(&sta->lock);
 196 }
 197
 198 static inline int ieee80211_ac_from_tid(int tid)
 199 {
 200         return ieee802_1d_to_ac[tid & 7];
 201 }
 202
 203 int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
 204 {
 205         struct ieee80211_local *local = hw_to_local(hw);
 206         struct sta_info *sta;
 207         struct ieee80211_sub_if_data *sdata;
 208         u8 *state;
 209         int ret = 0;
 210         u16 start_seq_num;
 211
 212         if (WARN_ON(!local->ops->ampdu_action))
 213                 return -EINVAL;
 214
 215         if ((tid >= STA_TID_NUM) || !(hw->flags & IEEE80211_HW_AMPDU_AGGREGATION))
 216                 return -EINVAL;
 217
 218 #ifdef CONFIG_MAC80211_HT_DEBUG
 219         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 220                ra, tid);
 221 #endif /* CONFIG_MAC80211_HT_DEBUG */
 222
 223         rcu_read_lock();
 224
 225         sta = sta_info_get(local, ra);
 226         if (!sta) {
 227 #ifdef CONFIG_MAC80211_HT_DEBUG
 228                 printk(KERN_DEBUG "Could not find the station\n");
 229 #endif
 230                 ret = -ENOENT;
 231                 goto unlock;
 232         }
 233
 234         /*
 235          * The aggregation code is not prepared to handle
 236          * anything but STA/AP due to the BSSID handling.
 237          * IBSS could work in the code but isn't supported
 238          * by drivers or the standard.
 239          */
 240         if (sta->sdata->vif.type != NL80211_IFTYPE_STATION &&
 241             sta->sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 242             sta->sdata->vif.type != NL80211_IFTYPE_AP) {
 243                 ret = -EINVAL;
 244                 goto unlock;
 245         }
 246
 247         if (test_sta_flags(sta, WLAN_STA_SUSPEND)) {
 248 #ifdef CONFIG_MAC80211_HT_DEBUG
 249                 printk(KERN_DEBUG "Suspend in progress. "
 250                        "Denying BA session request\n");
 251 #endif
 252                 ret = -EINVAL;
 253                 goto unlock;
 254         }
 255
 256         spin_lock_bh(&sta->lock);
 257         spin_lock(&local->ampdu_lock);
 258
 259         sdata = sta->sdata;
 260
 261         /* we have tried too many times, receiver does not want A-MPDU */
 262         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 263                 ret = -EBUSY;
 264                 goto err_unlock_sta;
 265         }
 266
 267         state = &sta->ampdu_mlme.tid_state_tx[tid];
 268         /* check if the TID is not in aggregation flow already */
 269         if (*state != HT_AGG_STATE_IDLE) {
 270 #ifdef CONFIG_MAC80211_HT_DEBUG
 271                 printk(KERN_DEBUG "BA request denied - session is not "
 272                                  "idle on tid %u\n", tid);
 273 #endif /* CONFIG_MAC80211_HT_DEBUG */
 274                 ret = -EAGAIN;
 275                 goto err_unlock_sta;
 276         }
 277
 278         /*
 279          * While we're asking the driver about the aggregation,
 280          * stop the AC queue so that we don't have to worry
 281          * about frames that came in while we were doing that,
 282          * which would require us to put them to the AC pending
 283          * afterwards which just makes the code more complex.
 284          */
 285         ieee80211_stop_queue_by_reason(
 286                 &local->hw, ieee80211_ac_from_tid(tid),
 287                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 288
 289         /* prepare A-MPDU MLME for Tx aggregation */
 290         sta->ampdu_mlme.tid_tx[tid] =
 291                         kmalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 292         if (!sta->ampdu_mlme.tid_tx[tid]) {
 293 #ifdef CONFIG_MAC80211_HT_DEBUG
 294                 if (net_ratelimit())
 295                         printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
 296                                         tid);
 297 #endif
 298                 ret = -ENOMEM;
 299                 goto err_wake_queue;
 300         }
 301
 302         skb_queue_head_init(&sta->ampdu_mlme.tid_tx[tid]->pending);
 303
 304         /* Tx timer */
 305         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.function =
 306                         sta_addba_resp_timer_expired;
 307         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.data =
 308                         (unsigned long)&sta->timer_to_tid[tid];
 309         init_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 310
 311         /* Ok, the Addba frame hasn't been sent yet, but if the driver calls the
 312          * call back right away, it must see that the flow has begun */
 313         *state |= HT_ADDBA_REQUESTED_MSK;
 314
 315         start_seq_num = sta->tid_seq[tid];
 316
 317         ret = drv_ampdu_action(local, IEEE80211_AMPDU_TX_START,
 318                                &sta->sta, tid, &start_seq_num);
 319
 320         if (ret) {
 321 #ifdef CONFIG_MAC80211_HT_DEBUG
 322                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 323                                         " tid %d\n", tid);
 324 #endif /* CONFIG_MAC80211_HT_DEBUG */
 325                 *state = HT_AGG_STATE_IDLE;
 326                 goto err_free;
 327         }
 328
 329         /* Driver vetoed or OKed, but we can take packets again now */
 330         ieee80211_wake_queue_by_reason(
 331                 &local->hw, ieee80211_ac_from_tid(tid),
 332                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 333
 334         spin_unlock(&local->ampdu_lock);
 335         spin_unlock_bh(&sta->lock);
 336
 337         /* send an addBA request */
 338         sta->ampdu_mlme.dialog_token_allocator++;
 339         sta->ampdu_mlme.tid_tx[tid]->dialog_token =
 340                         sta->ampdu_mlme.dialog_token_allocator;
 341         sta->ampdu_mlme.tid_tx[tid]->ssn = start_seq_num;
 342
 343         ieee80211_send_addba_request(sta->sdata, ra, tid,
 344                          sta->ampdu_mlme.tid_tx[tid]->dialog_token,
 345                          sta->ampdu_mlme.tid_tx[tid]->ssn,
 346                          0x40, 5000);
 347         sta->ampdu_mlme.addba_req_num[tid]++;
 348         /* activate the timer for the recipient's addBA response */
 349         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
 350                                 jiffies + ADDBA_RESP_INTERVAL;
 351         add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 352 #ifdef CONFIG_MAC80211_HT_DEBUG
 353         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 354 #endif
 355         goto unlock;
 356
 357  err_free:
 358         kfree(sta->ampdu_mlme.tid_tx[tid]);
 359         sta->ampdu_mlme.tid_tx[tid] = NULL;
 360  err_wake_queue:
 361         ieee80211_wake_queue_by_reason(
 362                 &local->hw, ieee80211_ac_from_tid(tid),
 363                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 364  err_unlock_sta:
 365         spin_unlock(&local->ampdu_lock);
 366         spin_unlock_bh(&sta->lock);
 367  unlock:
 368         rcu_read_unlock();
 369         return ret;
 370 }
 371 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 372
 373 /*
 374  * splice packets from the STA's pending to the local pending,
 375  * requires a call to ieee80211_agg_splice_finish and holding
 376  * local->ampdu_lock across both calls.
 377  */
 378 static void ieee80211_agg_splice_packets(struct ieee80211_local *local,
 379                                          struct sta_info *sta, u16 tid)
 380 {
 381         unsigned long flags;
 382         u16 queue = ieee80211_ac_from_tid(tid);
 383
 384         ieee80211_stop_queue_by_reason(
 385                 &local->hw, queue,
 386                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 387
 388         if (!(sta->ampdu_mlme.tid_state_tx[tid] & HT_ADDBA_REQUESTED_MSK))
 389                 return;
 390
 391         if (WARN(!sta->ampdu_mlme.tid_tx[tid],
 392                  "TID %d gone but expected when splicing aggregates from"
 393                  "the pending queue\n", tid))
 394                 return;
 395
 396         if (!skb_queue_empty(&sta->ampdu_mlme.tid_tx[tid]->pending)) {
 397                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 398                 /* mark queue as pending, it is stopped already */
 399                 __set_bit(IEEE80211_QUEUE_STOP_REASON_PENDING,
 400                           &local->queue_stop_reasons[queue]);
 401                 /* copy over remaining packets */
 402                 skb_queue_splice_tail_init(
 403                         &sta->ampdu_mlme.tid_tx[tid]->pending,
 404                         &local->pending[queue]);
 405                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 406         }
 407 }
 408
 409 static void ieee80211_agg_splice_finish(struct ieee80211_local *local,
 410                                         struct sta_info *sta, u16 tid)
 411 {
 412         u16 queue = ieee80211_ac_from_tid(tid);
 413
 414         ieee80211_wake_queue_by_reason(
 415                 &local->hw, queue,
 416                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 417 }
 418
 419 /* caller must hold sta->lock */
 420 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 421                                          struct sta_info *sta, u16 tid)
 422 {
 423 #ifdef CONFIG_MAC80211_HT_DEBUG
 424         printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
 425 #endif
 426
 427         spin_lock(&local->ampdu_lock);
 428         ieee80211_agg_splice_packets(local, sta, tid);
 429         /*
 430          * NB: we rely on sta->lock being taken in the TX
 431          * processing here when adding to the pending queue,
 432          * otherwise we could only change the state of the
 433          * session to OPERATIONAL _here_.
 434          */
 435         ieee80211_agg_splice_finish(local, sta, tid);
 436         spin_unlock(&local->ampdu_lock);
 437
 438         drv_ampdu_action(local, IEEE80211_AMPDU_TX_OPERATIONAL,
 439                          &sta->sta, tid, NULL);
 440 }
 441
 442 void ieee80211_start_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u16 tid)
 443 {
 444         struct ieee80211_local *local = hw_to_local(hw);
 445         struct sta_info *sta;
 446         u8 *state;
 447
 448         if (tid >= STA_TID_NUM) {
 449 #ifdef CONFIG_MAC80211_HT_DEBUG
 450                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 451                                 tid, STA_TID_NUM);
 452 #endif
 453                 return;
 454         }
 455
 456         rcu_read_lock();
 457         sta = sta_info_get(local, ra);
 458         if (!sta) {
 459                 rcu_read_unlock();
 460 #ifdef CONFIG_MAC80211_HT_DEBUG
 461                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 462 #endif
 463                 return;
 464         }
 465
 466         state = &sta->ampdu_mlme.tid_state_tx[tid];
 467         spin_lock_bh(&sta->lock);
 468
 469         if (WARN_ON(!(*state & HT_ADDBA_REQUESTED_MSK))) {
 470 #ifdef CONFIG_MAC80211_HT_DEBUG
 471                 printk(KERN_DEBUG "addBA was not requested yet, state is %d\n",
 472                                 *state);
 473 #endif
 474                 spin_unlock_bh(&sta->lock);
 475                 rcu_read_unlock();
 476                 return;
 477         }
 478
 479         if (WARN_ON(*state & HT_ADDBA_DRV_READY_MSK))
 480                 goto out;
 481
 482         *state |= HT_ADDBA_DRV_READY_MSK;
 483
 484         if (*state == HT_AGG_STATE_OPERATIONAL)
 485                 ieee80211_agg_tx_operational(local, sta, tid);
 486
 487  out:
 488         spin_unlock_bh(&sta->lock);
 489         rcu_read_unlock();
 490 }
 491 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb);
 492
 493 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
 494                                       const u8 *ra, u16 tid)
 495 {
 496         struct ieee80211_local *local = hw_to_local(hw);
 497         struct ieee80211_ra_tid *ra_tid;
 498         struct sk_buff *skb = dev_alloc_skb(0);
 499
 500         if (unlikely(!skb)) {
 501 #ifdef CONFIG_MAC80211_HT_DEBUG
 502                 if (net_ratelimit())
 503                         printk(KERN_WARNING "%s: Not enough memory, "
 504                                "dropping start BA session", skb->dev->name);
 505 #endif
 506                 return;
 507         }
 508         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 509         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 510         ra_tid->tid = tid;
 511
 512         skb->pkt_type = IEEE80211_ADDBA_MSG;
 513         skb_queue_tail(&local->skb_queue, skb);
 514         tasklet_schedule(&local->tasklet);
 515 }
 516 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 517
 518 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 519                                    enum ieee80211_back_parties initiator)
 520 {
 521         u8 *state;
 522         int ret;
 523
 524         /* check if the TID is in aggregation */
 525         state = &sta->ampdu_mlme.tid_state_tx[tid];
 526         spin_lock_bh(&sta->lock);
 527
 528         if (*state != HT_AGG_STATE_OPERATIONAL) {
 529                 ret = -ENOENT;
 530                 goto unlock;
 531         }
 532
 533         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator);
 534
 535  unlock:
 536         spin_unlock_bh(&sta->lock);
 537         return ret;
 538 }
 539
 540 int ieee80211_stop_tx_ba_session(struct ieee80211_hw *hw,
 541                                  u8 *ra, u16 tid,
 542                                  enum ieee80211_back_parties initiator)
 543 {
 544         struct ieee80211_local *local = hw_to_local(hw);
 545         struct sta_info *sta;
 546         int ret = 0;
 547
 548         if (!local->ops->ampdu_action)
 549                 return -EINVAL;
 550
 551         if (tid >= STA_TID_NUM)
 552                 return -EINVAL;
 553
 554         rcu_read_lock();
 555         sta = sta_info_get(local, ra);
 556         if (!sta) {
 557                 rcu_read_unlock();
 558                 return -ENOENT;
 559         }
 560
 561         ret = __ieee80211_stop_tx_ba_session(sta, tid, initiator);
 562         rcu_read_unlock();
 563         return ret;
 564 }
 565 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 566
 567 void ieee80211_stop_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u8 tid)
 568 {
 569         struct ieee80211_local *local = hw_to_local(hw);
 570         struct sta_info *sta;
 571         u8 *state;
 572
 573         if (tid >= STA_TID_NUM) {
 574 #ifdef CONFIG_MAC80211_HT_DEBUG
 575                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 576                                 tid, STA_TID_NUM);
 577 #endif
 578                 return;
 579         }
 580
 581 #ifdef CONFIG_MAC80211_HT_DEBUG
 582         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 583                ra, tid);
 584 #endif /* CONFIG_MAC80211_HT_DEBUG */
 585
 586         rcu_read_lock();
 587         sta = sta_info_get(local, ra);
 588         if (!sta) {
 589 #ifdef CONFIG_MAC80211_HT_DEBUG
 590                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 591 #endif
 592                 rcu_read_unlock();
 593                 return;
 594         }
 595         state = &sta->ampdu_mlme.tid_state_tx[tid];
 596
 597         /* NOTE: no need to use sta->lock in this state check, as
 598          * ieee80211_stop_tx_ba_session will let only one stop call to
 599          * pass through per sta/tid
 600          */
 601         if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) {
 602 #ifdef CONFIG_MAC80211_HT_DEBUG
 603                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 604 #endif
 605                 rcu_read_unlock();
 606                 return;
 607         }
 608
 609         if (*state & HT_AGG_STATE_INITIATOR_MSK)
 610                 ieee80211_send_delba(sta->sdata, ra, tid,
 611                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 612
 613         spin_lock_bh(&sta->lock);
 614         spin_lock(&local->ampdu_lock);
 615
 616         ieee80211_agg_splice_packets(local, sta, tid);
 617
 618         *state = HT_AGG_STATE_IDLE;
 619         /* from now on packets are no longer put onto sta->pending */
 620         kfree(sta->ampdu_mlme.tid_tx[tid]);
 621         sta->ampdu_mlme.tid_tx[tid] = NULL;
 622
 623         ieee80211_agg_splice_finish(local, sta, tid);
 624
 625         spin_unlock(&local->ampdu_lock);
 626         spin_unlock_bh(&sta->lock);
 627
 628         rcu_read_unlock();
 629 }
 630 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb);
 631
 632 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
 633                                      const u8 *ra, u16 tid)
 634 {
 635         struct ieee80211_local *local = hw_to_local(hw);
 636         struct ieee80211_ra_tid *ra_tid;
 637         struct sk_buff *skb = dev_alloc_skb(0);
 638
 639         if (unlikely(!skb)) {
 640 #ifdef CONFIG_MAC80211_HT_DEBUG
 641                 if (net_ratelimit())
 642                         printk(KERN_WARNING "%s: Not enough memory, "
 643                                "dropping stop BA session", skb->dev->name);
 644 #endif
 645                 return;
 646         }
 647         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 648         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 649         ra_tid->tid = tid;
 650
 651         skb->pkt_type = IEEE80211_DELBA_MSG;
 652         skb_queue_tail(&local->skb_queue, skb);
 653         tasklet_schedule(&local->tasklet);
 654 }
 655 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 656
 657
 658 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 659                                   struct sta_info *sta,
 660                                   struct ieee80211_mgmt *mgmt,
 661                                   size_t len)
 662 {
 663         u16 capab, tid;
 664         u8 *state;
 665
 666         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 667         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 668
 669         state = &sta->ampdu_mlme.tid_state_tx[tid];
 670
 671         spin_lock_bh(&sta->lock);
 672
 673         if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
 674                 spin_unlock_bh(&sta->lock);
 675                 return;
 676         }
 677
 678         if (mgmt->u.action.u.addba_resp.dialog_token !=
 679                 sta->ampdu_mlme.tid_tx[tid]->dialog_token) {
 680                 spin_unlock_bh(&sta->lock);
 681 #ifdef CONFIG_MAC80211_HT_DEBUG
 682                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 683 #endif /* CONFIG_MAC80211_HT_DEBUG */
 684                 return;
 685         }
 686
 687         del_timer_sync(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 688 #ifdef CONFIG_MAC80211_HT_DEBUG
 689         printk(KERN_DEBUG "switched off addBA timer for tid %d \n", tid);
 690 #endif /* CONFIG_MAC80211_HT_DEBUG */
 691         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 692                         == WLAN_STATUS_SUCCESS) {
 693                 u8 curstate = *state;
 694
 695                 *state |= HT_ADDBA_RECEIVED_MSK;
 696
 697                 if (*state != curstate && *state == HT_AGG_STATE_OPERATIONAL)
 698                         ieee80211_agg_tx_operational(local, sta, tid);
 699
 700                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 701         } else {
 702                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 703         }
 704         spin_unlock_bh(&sta->lock);
 705 }