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 static 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         state = &sta->ampdu_mlme.tid_state_tx[tid];
 134
 135         if (*state == HT_AGG_STATE_OPERATIONAL)
 136                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 137
 138         *state = HT_AGG_STATE_REQ_STOP_BA_MSK |
 139                 (initiator << HT_AGG_STATE_INITIATOR_SHIFT);
 140
 141         ret = drv_ampdu_action(local, IEEE80211_AMPDU_TX_STOP,
 142                                &sta->sta, tid, NULL);
 143
 144         /* HW shall not deny going back to legacy */
 145         if (WARN_ON(ret)) {
 146                 *state = HT_AGG_STATE_OPERATIONAL;
 147                 /*
 148                  * We may have pending packets get stuck in this case...
 149                  * Not bothering with a workaround for now.
 150                  */
 151         }
 152
 153         return ret;
 154 }
 155
 156 /*
 157  * After sending add Block Ack request we activated a timer until
 158  * add Block Ack response will arrive from the recipient.
 159  * If this timer expires sta_addba_resp_timer_expired will be executed.
 160  */
 161 static void sta_addba_resp_timer_expired(unsigned long data)
 162 {
 163         /* not an elegant detour, but there is no choice as the timer passes
 164          * only one argument, and both sta_info and TID are needed, so init
 165          * flow in sta_info_create gives the TID as data, while the timer_to_id
 166          * array gives the sta through container_of */
 167         u16 tid = *(u8 *)data;
 168         struct sta_info *sta = container_of((void *)data,
 169                 struct sta_info, timer_to_tid[tid]);
 170         u8 *state;
 171
 172         state = &sta->ampdu_mlme.tid_state_tx[tid];
 173
 174         /* check if the TID waits for addBA response */
 175         spin_lock_bh(&sta->lock);
 176         if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
 177                 spin_unlock_bh(&sta->lock);
 178                 *state = HT_AGG_STATE_IDLE;
 179 #ifdef CONFIG_MAC80211_HT_DEBUG
 180                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 181                                 "expecting addBA response there", tid);
 182 #endif
 183                 return;
 184         }
 185
 186 #ifdef CONFIG_MAC80211_HT_DEBUG
 187         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 188 #endif
 189
 190         ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 191         spin_unlock_bh(&sta->lock);
 192 }
 193
 194 static inline int ieee80211_ac_from_tid(int tid)
 195 {
 196         return ieee802_1d_to_ac[tid & 7];
 197 }
 198
 199 int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
 200 {
 201         struct ieee80211_local *local = hw_to_local(hw);
 202         struct sta_info *sta;
 203         struct ieee80211_sub_if_data *sdata;
 204         u8 *state;
 205         int ret = 0;
 206         u16 start_seq_num;
 207
 208         if (WARN_ON(!local->ops->ampdu_action))
 209                 return -EINVAL;
 210
 211         if ((tid >= STA_TID_NUM) || !(hw->flags & IEEE80211_HW_AMPDU_AGGREGATION))
 212                 return -EINVAL;
 213
 214 #ifdef CONFIG_MAC80211_HT_DEBUG
 215         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 216                ra, tid);
 217 #endif /* CONFIG_MAC80211_HT_DEBUG */
 218
 219         rcu_read_lock();
 220
 221         sta = sta_info_get(local, ra);
 222         if (!sta) {
 223 #ifdef CONFIG_MAC80211_HT_DEBUG
 224                 printk(KERN_DEBUG "Could not find the station\n");
 225 #endif
 226                 ret = -ENOENT;
 227                 goto unlock;
 228         }
 229
 230         /*
 231          * The aggregation code is not prepared to handle
 232          * anything but STA/AP due to the BSSID handling.
 233          * IBSS could work in the code but isn't supported
 234          * by drivers or the standard.
 235          */
 236         if (sta->sdata->vif.type != NL80211_IFTYPE_STATION &&
 237             sta->sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 238             sta->sdata->vif.type != NL80211_IFTYPE_AP) {
 239                 ret = -EINVAL;
 240                 goto unlock;
 241         }
 242
 243         if (test_sta_flags(sta, WLAN_STA_SUSPEND)) {
 244 #ifdef CONFIG_MAC80211_HT_DEBUG
 245                 printk(KERN_DEBUG "Suspend in progress. "
 246                        "Denying BA session request\n");
 247 #endif
 248                 ret = -EINVAL;
 249                 goto unlock;
 250         }
 251
 252         spin_lock_bh(&sta->lock);
 253         spin_lock(&local->ampdu_lock);
 254
 255         sdata = sta->sdata;
 256
 257         /* we have tried too many times, receiver does not want A-MPDU */
 258         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 259                 ret = -EBUSY;
 260                 goto err_unlock_sta;
 261         }
 262
 263         state = &sta->ampdu_mlme.tid_state_tx[tid];
 264         /* check if the TID is not in aggregation flow already */
 265         if (*state != HT_AGG_STATE_IDLE) {
 266 #ifdef CONFIG_MAC80211_HT_DEBUG
 267                 printk(KERN_DEBUG "BA request denied - session is not "
 268                                  "idle on tid %u\n", tid);
 269 #endif /* CONFIG_MAC80211_HT_DEBUG */
 270                 ret = -EAGAIN;
 271                 goto err_unlock_sta;
 272         }
 273
 274         /*
 275          * While we're asking the driver about the aggregation,
 276          * stop the AC queue so that we don't have to worry
 277          * about frames that came in while we were doing that,
 278          * which would require us to put them to the AC pending
 279          * afterwards which just makes the code more complex.
 280          */
 281         ieee80211_stop_queue_by_reason(
 282                 &local->hw, ieee80211_ac_from_tid(tid),
 283                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 284
 285         /* prepare A-MPDU MLME for Tx aggregation */
 286         sta->ampdu_mlme.tid_tx[tid] =
 287                         kmalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 288         if (!sta->ampdu_mlme.tid_tx[tid]) {
 289 #ifdef CONFIG_MAC80211_HT_DEBUG
 290                 if (net_ratelimit())
 291                         printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
 292                                         tid);
 293 #endif
 294                 ret = -ENOMEM;
 295                 goto err_wake_queue;
 296         }
 297
 298         skb_queue_head_init(&sta->ampdu_mlme.tid_tx[tid]->pending);
 299
 300         /* Tx timer */
 301         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.function =
 302                         sta_addba_resp_timer_expired;
 303         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.data =
 304                         (unsigned long)&sta->timer_to_tid[tid];
 305         init_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 306
 307         /* Ok, the Addba frame hasn't been sent yet, but if the driver calls the
 308          * call back right away, it must see that the flow has begun */
 309         *state |= HT_ADDBA_REQUESTED_MSK;
 310
 311         start_seq_num = sta->tid_seq[tid];
 312
 313         ret = drv_ampdu_action(local, IEEE80211_AMPDU_TX_START,
 314                                &sta->sta, tid, &start_seq_num);
 315
 316         if (ret) {
 317 #ifdef CONFIG_MAC80211_HT_DEBUG
 318                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 319                                         " tid %d\n", tid);
 320 #endif /* CONFIG_MAC80211_HT_DEBUG */
 321                 *state = HT_AGG_STATE_IDLE;
 322                 goto err_free;
 323         }
 324
 325         /* Driver vetoed or OKed, but we can take packets again now */
 326         ieee80211_wake_queue_by_reason(
 327                 &local->hw, ieee80211_ac_from_tid(tid),
 328                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 329
 330         spin_unlock(&local->ampdu_lock);
 331         spin_unlock_bh(&sta->lock);
 332
 333         /* send an addBA request */
 334         sta->ampdu_mlme.dialog_token_allocator++;
 335         sta->ampdu_mlme.tid_tx[tid]->dialog_token =
 336                         sta->ampdu_mlme.dialog_token_allocator;
 337         sta->ampdu_mlme.tid_tx[tid]->ssn = start_seq_num;
 338
 339         ieee80211_send_addba_request(sta->sdata, ra, tid,
 340                          sta->ampdu_mlme.tid_tx[tid]->dialog_token,
 341                          sta->ampdu_mlme.tid_tx[tid]->ssn,
 342                          0x40, 5000);
 343         sta->ampdu_mlme.addba_req_num[tid]++;
 344         /* activate the timer for the recipient's addBA response */
 345         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
 346                                 jiffies + ADDBA_RESP_INTERVAL;
 347         add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 348 #ifdef CONFIG_MAC80211_HT_DEBUG
 349         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 350 #endif
 351         goto unlock;
 352
 353  err_free:
 354         kfree(sta->ampdu_mlme.tid_tx[tid]);
 355         sta->ampdu_mlme.tid_tx[tid] = NULL;
 356  err_wake_queue:
 357         ieee80211_wake_queue_by_reason(
 358                 &local->hw, ieee80211_ac_from_tid(tid),
 359                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 360  err_unlock_sta:
 361         spin_unlock(&local->ampdu_lock);
 362         spin_unlock_bh(&sta->lock);
 363  unlock:
 364         rcu_read_unlock();
 365         return ret;
 366 }
 367 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 368
 369 /*
 370  * splice packets from the STA's pending to the local pending,
 371  * requires a call to ieee80211_agg_splice_finish and holding
 372  * local->ampdu_lock across both calls.
 373  */
 374 static void ieee80211_agg_splice_packets(struct ieee80211_local *local,
 375                                          struct sta_info *sta, u16 tid)
 376 {
 377         unsigned long flags;
 378         u16 queue = ieee80211_ac_from_tid(tid);
 379
 380         ieee80211_stop_queue_by_reason(
 381                 &local->hw, queue,
 382                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 383
 384         if (!(sta->ampdu_mlme.tid_state_tx[tid] & HT_ADDBA_REQUESTED_MSK))
 385                 return;
 386
 387         if (WARN(!sta->ampdu_mlme.tid_tx[tid],
 388                  "TID %d gone but expected when splicing aggregates from"
 389                  "the pending queue\n", tid))
 390                 return;
 391
 392         if (!skb_queue_empty(&sta->ampdu_mlme.tid_tx[tid]->pending)) {
 393                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 394                 /* copy over remaining packets */
 395                 skb_queue_splice_tail_init(
 396                         &sta->ampdu_mlme.tid_tx[tid]->pending,
 397                         &local->pending[queue]);
 398                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 399         }
 400 }
 401
 402 static void ieee80211_agg_splice_finish(struct ieee80211_local *local,
 403                                         struct sta_info *sta, u16 tid)
 404 {
 405         u16 queue = ieee80211_ac_from_tid(tid);
 406
 407         ieee80211_wake_queue_by_reason(
 408                 &local->hw, queue,
 409                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 410 }
 411
 412 /* caller must hold sta->lock */
 413 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 414                                          struct sta_info *sta, u16 tid)
 415 {
 416 #ifdef CONFIG_MAC80211_HT_DEBUG
 417         printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
 418 #endif
 419
 420         spin_lock(&local->ampdu_lock);
 421         ieee80211_agg_splice_packets(local, sta, tid);
 422         /*
 423          * NB: we rely on sta->lock being taken in the TX
 424          * processing here when adding to the pending queue,
 425          * otherwise we could only change the state of the
 426          * session to OPERATIONAL _here_.
 427          */
 428         ieee80211_agg_splice_finish(local, sta, tid);
 429         spin_unlock(&local->ampdu_lock);
 430
 431         drv_ampdu_action(local, IEEE80211_AMPDU_TX_OPERATIONAL,
 432                          &sta->sta, tid, NULL);
 433 }
 434
 435 void ieee80211_start_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u16 tid)
 436 {
 437         struct ieee80211_local *local = hw_to_local(hw);
 438         struct sta_info *sta;
 439         u8 *state;
 440
 441         if (tid >= STA_TID_NUM) {
 442 #ifdef CONFIG_MAC80211_HT_DEBUG
 443                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 444                                 tid, STA_TID_NUM);
 445 #endif
 446                 return;
 447         }
 448
 449         rcu_read_lock();
 450         sta = sta_info_get(local, ra);
 451         if (!sta) {
 452                 rcu_read_unlock();
 453 #ifdef CONFIG_MAC80211_HT_DEBUG
 454                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 455 #endif
 456                 return;
 457         }
 458
 459         state = &sta->ampdu_mlme.tid_state_tx[tid];
 460         spin_lock_bh(&sta->lock);
 461
 462         if (WARN_ON(!(*state & HT_ADDBA_REQUESTED_MSK))) {
 463 #ifdef CONFIG_MAC80211_HT_DEBUG
 464                 printk(KERN_DEBUG "addBA was not requested yet, state is %d\n",
 465                                 *state);
 466 #endif
 467                 spin_unlock_bh(&sta->lock);
 468                 rcu_read_unlock();
 469                 return;
 470         }
 471
 472         if (WARN_ON(*state & HT_ADDBA_DRV_READY_MSK))
 473                 goto out;
 474
 475         *state |= HT_ADDBA_DRV_READY_MSK;
 476
 477         if (*state == HT_AGG_STATE_OPERATIONAL)
 478                 ieee80211_agg_tx_operational(local, sta, tid);
 479
 480  out:
 481         spin_unlock_bh(&sta->lock);
 482         rcu_read_unlock();
 483 }
 484 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb);
 485
 486 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
 487                                       const u8 *ra, u16 tid)
 488 {
 489         struct ieee80211_local *local = hw_to_local(hw);
 490         struct ieee80211_ra_tid *ra_tid;
 491         struct sk_buff *skb = dev_alloc_skb(0);
 492
 493         if (unlikely(!skb)) {
 494 #ifdef CONFIG_MAC80211_HT_DEBUG
 495                 if (net_ratelimit())
 496                         printk(KERN_WARNING "%s: Not enough memory, "
 497                                "dropping start BA session", skb->dev->name);
 498 #endif
 499                 return;
 500         }
 501         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 502         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 503         ra_tid->tid = tid;
 504
 505         skb->pkt_type = IEEE80211_ADDBA_MSG;
 506         skb_queue_tail(&local->skb_queue, skb);
 507         tasklet_schedule(&local->tasklet);
 508 }
 509 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 510
 511 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 512                                    enum ieee80211_back_parties initiator)
 513 {
 514         u8 *state;
 515         int ret;
 516
 517         /* check if the TID is in aggregation */
 518         state = &sta->ampdu_mlme.tid_state_tx[tid];
 519         spin_lock_bh(&sta->lock);
 520
 521         if (*state != HT_AGG_STATE_OPERATIONAL) {
 522                 ret = -ENOENT;
 523                 goto unlock;
 524         }
 525
 526 #ifdef CONFIG_MAC80211_HT_DEBUG
 527         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 528                sta->sta.addr, tid);
 529 #endif /* CONFIG_MAC80211_HT_DEBUG */
 530
 531         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator);
 532
 533  unlock:
 534         spin_unlock_bh(&sta->lock);
 535         return ret;
 536 }
 537
 538 int ieee80211_stop_tx_ba_session(struct ieee80211_hw *hw,
 539                                  u8 *ra, u16 tid,
 540                                  enum ieee80211_back_parties initiator)
 541 {
 542         struct ieee80211_local *local = hw_to_local(hw);
 543         struct sta_info *sta;
 544         int ret = 0;
 545
 546         if (WARN_ON(!local->ops->ampdu_action))
 547                 return -EINVAL;
 548
 549         if (tid >= STA_TID_NUM)
 550                 return -EINVAL;
 551
 552         rcu_read_lock();
 553         sta = sta_info_get(local, ra);
 554         if (!sta) {
 555                 rcu_read_unlock();
 556                 return -ENOENT;
 557         }
 558
 559         ret = __ieee80211_stop_tx_ba_session(sta, tid, initiator);
 560         rcu_read_unlock();
 561         return ret;
 562 }
 563 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 564
 565 void ieee80211_stop_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u8 tid)
 566 {
 567         struct ieee80211_local *local = hw_to_local(hw);
 568         struct sta_info *sta;
 569         u8 *state;
 570
 571         if (tid >= STA_TID_NUM) {
 572 #ifdef CONFIG_MAC80211_HT_DEBUG
 573                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 574                                 tid, STA_TID_NUM);
 575 #endif
 576                 return;
 577         }
 578
 579 #ifdef CONFIG_MAC80211_HT_DEBUG
 580         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 581                ra, tid);
 582 #endif /* CONFIG_MAC80211_HT_DEBUG */
 583
 584         rcu_read_lock();
 585         sta = sta_info_get(local, ra);
 586         if (!sta) {
 587 #ifdef CONFIG_MAC80211_HT_DEBUG
 588                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 589 #endif
 590                 rcu_read_unlock();
 591                 return;
 592         }
 593         state = &sta->ampdu_mlme.tid_state_tx[tid];
 594
 595         /* NOTE: no need to use sta->lock in this state check, as
 596          * ieee80211_stop_tx_ba_session will let only one stop call to
 597          * pass through per sta/tid
 598          */
 599         if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) {
 600 #ifdef CONFIG_MAC80211_HT_DEBUG
 601                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 602 #endif
 603                 rcu_read_unlock();
 604                 return;
 605         }
 606
 607         if (*state & HT_AGG_STATE_INITIATOR_MSK)
 608                 ieee80211_send_delba(sta->sdata, ra, tid,
 609                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 610
 611         spin_lock_bh(&sta->lock);
 612         spin_lock(&local->ampdu_lock);
 613
 614         ieee80211_agg_splice_packets(local, sta, tid);
 615
 616         *state = HT_AGG_STATE_IDLE;
 617         /* from now on packets are no longer put onto sta->pending */
 618         kfree(sta->ampdu_mlme.tid_tx[tid]);
 619         sta->ampdu_mlme.tid_tx[tid] = NULL;
 620
 621         ieee80211_agg_splice_finish(local, sta, tid);
 622
 623         spin_unlock(&local->ampdu_lock);
 624         spin_unlock_bh(&sta->lock);
 625
 626         rcu_read_unlock();
 627 }
 628 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb);
 629
 630 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
 631                                      const u8 *ra, u16 tid)
 632 {
 633         struct ieee80211_local *local = hw_to_local(hw);
 634         struct ieee80211_ra_tid *ra_tid;
 635         struct sk_buff *skb = dev_alloc_skb(0);
 636
 637         if (unlikely(!skb)) {
 638 #ifdef CONFIG_MAC80211_HT_DEBUG
 639                 if (net_ratelimit())
 640                         printk(KERN_WARNING "%s: Not enough memory, "
 641                                "dropping stop BA session", skb->dev->name);
 642 #endif
 643                 return;
 644         }
 645         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 646         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 647         ra_tid->tid = tid;
 648
 649         skb->pkt_type = IEEE80211_DELBA_MSG;
 650         skb_queue_tail(&local->skb_queue, skb);
 651         tasklet_schedule(&local->tasklet);
 652 }
 653 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 654
 655
 656 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 657                                   struct sta_info *sta,
 658                                   struct ieee80211_mgmt *mgmt,
 659                                   size_t len)
 660 {
 661         u16 capab, tid;
 662         u8 *state;
 663
 664         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 665         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 666
 667         state = &sta->ampdu_mlme.tid_state_tx[tid];
 668
 669         del_timer_sync(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 670
 671         spin_lock_bh(&sta->lock);
 672
 673         if (!(*state & HT_ADDBA_REQUESTED_MSK))
 674                 goto timer_still_needed;
 675
 676         if (mgmt->u.action.u.addba_resp.dialog_token !=
 677                 sta->ampdu_mlme.tid_tx[tid]->dialog_token) {
 678 #ifdef CONFIG_MAC80211_HT_DEBUG
 679                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 680 #endif /* CONFIG_MAC80211_HT_DEBUG */
 681                 goto timer_still_needed;
 682         }
 683
 684 #ifdef CONFIG_MAC80211_HT_DEBUG
 685         printk(KERN_DEBUG "switched off addBA timer for tid %d \n", tid);
 686 #endif /* CONFIG_MAC80211_HT_DEBUG */
 687
 688         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 689                         == WLAN_STATUS_SUCCESS) {
 690                 u8 curstate = *state;
 691
 692                 *state |= HT_ADDBA_RECEIVED_MSK;
 693
 694                 if (*state != curstate && *state == HT_AGG_STATE_OPERATIONAL)
 695                         ieee80211_agg_tx_operational(local, sta, tid);
 696
 697                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 698         } else {
 699                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 700         }
 701
 702         goto out;
 703
 704  timer_still_needed:
 705         add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 706  out:
 707         spin_unlock_bh(&sta->lock);
 708 }