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);
  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_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 124         ieee80211_tx_skb(sdata, skb);
 125 }
 126
 127 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 128                                     enum ieee80211_back_parties initiator)
 129 {
 130         struct ieee80211_local *local = sta->local;
 131         int ret;
 132         u8 *state;
 133
 134 #ifdef CONFIG_MAC80211_HT_DEBUG
 135         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 136                sta->sta.addr, tid);
 137 #endif /* CONFIG_MAC80211_HT_DEBUG */
 138
 139         state = &sta->ampdu_mlme.tid_state_tx[tid];
 140
 141         if (*state == HT_AGG_STATE_OPERATIONAL)
 142                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 143
 144         *state = HT_AGG_STATE_REQ_STOP_BA_MSK |
 145                 (initiator << HT_AGG_STATE_INITIATOR_SHIFT);
 146
 147         ret = drv_ampdu_action(local, &sta->sdata->vif,
 148                                IEEE80211_AMPDU_TX_STOP,
 149                                &sta->sta, tid, NULL);
 150
 151         /* HW shall not deny going back to legacy */
 152         if (WARN_ON(ret)) {
 153                 /*
 154                  * We may have pending packets get stuck in this case...
 155                  * Not bothering with a workaround for now.
 156                  */
 157         }
 158
 159         return ret;
 160 }
 161
 162 /*
 163  * After sending add Block Ack request we activated a timer until
 164  * add Block Ack response will arrive from the recipient.
 165  * If this timer expires sta_addba_resp_timer_expired will be executed.
 166  */
 167 static void sta_addba_resp_timer_expired(unsigned long data)
 168 {
 169         /* not an elegant detour, but there is no choice as the timer passes
 170          * only one argument, and both sta_info and TID are needed, so init
 171          * flow in sta_info_create gives the TID as data, while the timer_to_id
 172          * array gives the sta through container_of */
 173         u16 tid = *(u8 *)data;
 174         struct sta_info *sta = container_of((void *)data,
 175                 struct sta_info, timer_to_tid[tid]);
 176         u8 *state;
 177
 178         state = &sta->ampdu_mlme.tid_state_tx[tid];
 179
 180         /* check if the TID waits for addBA response */
 181         spin_lock_bh(&sta->lock);
 182         if ((*state & (HT_ADDBA_REQUESTED_MSK | HT_ADDBA_RECEIVED_MSK |
 183                        HT_AGG_STATE_REQ_STOP_BA_MSK)) !=
 184                                                 HT_ADDBA_REQUESTED_MSK) {
 185                 spin_unlock_bh(&sta->lock);
 186 #ifdef CONFIG_MAC80211_HT_DEBUG
 187                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 188                                 "(or no longer) expecting addBA response there",
 189                         tid);
 190 #endif
 191                 return;
 192         }
 193
 194 #ifdef CONFIG_MAC80211_HT_DEBUG
 195         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 196 #endif
 197
 198         ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 199         spin_unlock_bh(&sta->lock);
 200 }
 201
 202 static inline int ieee80211_ac_from_tid(int tid)
 203 {
 204         return ieee802_1d_to_ac[tid & 7];
 205 }
 206
 207 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 208 {
 209         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 210         struct ieee80211_sub_if_data *sdata = sta->sdata;
 211         struct ieee80211_local *local = sdata->local;
 212         u8 *state;
 213         int ret = 0;
 214         u16 start_seq_num;
 215
 216         if (WARN_ON(!local->ops->ampdu_action))
 217                 return -EINVAL;
 218
 219         if ((tid >= STA_TID_NUM) ||
 220             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION))
 221                 return -EINVAL;
 222
 223 #ifdef CONFIG_MAC80211_HT_DEBUG
 224         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 225                pubsta->addr, tid);
 226 #endif /* CONFIG_MAC80211_HT_DEBUG */
 227
 228         /*
 229          * The aggregation code is not prepared to handle
 230          * anything but STA/AP due to the BSSID handling.
 231          * IBSS could work in the code but isn't supported
 232          * by drivers or the standard.
 233          */
 234         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 235             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 236             sdata->vif.type != NL80211_IFTYPE_AP)
 237                 return -EINVAL;
 238
 239         if (test_sta_flags(sta, WLAN_STA_SUSPEND)) {
 240 #ifdef CONFIG_MAC80211_HT_DEBUG
 241                 printk(KERN_DEBUG "Suspend in progress. "
 242                        "Denying BA session request\n");
 243 #endif
 244                 return -EINVAL;
 245         }
 246
 247         spin_lock_bh(&sta->lock);
 248         spin_lock(&local->ampdu_lock);
 249
 250         /* we have tried too many times, receiver does not want A-MPDU */
 251         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 252                 ret = -EBUSY;
 253                 goto err_unlock_sta;
 254         }
 255
 256         state = &sta->ampdu_mlme.tid_state_tx[tid];
 257         /* check if the TID is not in aggregation flow already */
 258         if (*state != HT_AGG_STATE_IDLE) {
 259 #ifdef CONFIG_MAC80211_HT_DEBUG
 260                 printk(KERN_DEBUG "BA request denied - session is not "
 261                                  "idle on tid %u\n", tid);
 262 #endif /* CONFIG_MAC80211_HT_DEBUG */
 263                 ret = -EAGAIN;
 264                 goto err_unlock_sta;
 265         }
 266
 267         /*
 268          * While we're asking the driver about the aggregation,
 269          * stop the AC queue so that we don't have to worry
 270          * about frames that came in while we were doing that,
 271          * which would require us to put them to the AC pending
 272          * afterwards which just makes the code more complex.
 273          */
 274         ieee80211_stop_queue_by_reason(
 275                 &local->hw, ieee80211_ac_from_tid(tid),
 276                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 277
 278         /* prepare A-MPDU MLME for Tx aggregation */
 279         sta->ampdu_mlme.tid_tx[tid] =
 280                         kmalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 281         if (!sta->ampdu_mlme.tid_tx[tid]) {
 282 #ifdef CONFIG_MAC80211_HT_DEBUG
 283                 if (net_ratelimit())
 284                         printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
 285                                         tid);
 286 #endif
 287                 ret = -ENOMEM;
 288                 goto err_wake_queue;
 289         }
 290
 291         skb_queue_head_init(&sta->ampdu_mlme.tid_tx[tid]->pending);
 292
 293         /* Tx timer */
 294         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.function =
 295                         sta_addba_resp_timer_expired;
 296         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.data =
 297                         (unsigned long)&sta->timer_to_tid[tid];
 298         init_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 299
 300         /* Ok, the Addba frame hasn't been sent yet, but if the driver calls the
 301          * call back right away, it must see that the flow has begun */
 302         *state |= HT_ADDBA_REQUESTED_MSK;
 303
 304         start_seq_num = sta->tid_seq[tid];
 305
 306         ret = drv_ampdu_action(local, &sdata->vif,
 307                                IEEE80211_AMPDU_TX_START,
 308                                pubsta, tid, &start_seq_num);
 309
 310         if (ret) {
 311 #ifdef CONFIG_MAC80211_HT_DEBUG
 312                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 313                                         " tid %d\n", tid);
 314 #endif /* CONFIG_MAC80211_HT_DEBUG */
 315                 *state = HT_AGG_STATE_IDLE;
 316                 goto err_free;
 317         }
 318
 319         /* Driver vetoed or OKed, but we can take packets again now */
 320         ieee80211_wake_queue_by_reason(
 321                 &local->hw, ieee80211_ac_from_tid(tid),
 322                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 323
 324         spin_unlock(&local->ampdu_lock);
 325         spin_unlock_bh(&sta->lock);
 326
 327         /* send an addBA request */
 328         sta->ampdu_mlme.dialog_token_allocator++;
 329         sta->ampdu_mlme.tid_tx[tid]->dialog_token =
 330                         sta->ampdu_mlme.dialog_token_allocator;
 331         sta->ampdu_mlme.tid_tx[tid]->ssn = start_seq_num;
 332
 333         ieee80211_send_addba_request(sdata, pubsta->addr, tid,
 334                          sta->ampdu_mlme.tid_tx[tid]->dialog_token,
 335                          sta->ampdu_mlme.tid_tx[tid]->ssn,
 336                          0x40, 5000);
 337         sta->ampdu_mlme.addba_req_num[tid]++;
 338         /* activate the timer for the recipient's addBA response */
 339         sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
 340                                 jiffies + ADDBA_RESP_INTERVAL;
 341         add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 342 #ifdef CONFIG_MAC80211_HT_DEBUG
 343         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 344 #endif
 345         return 0;
 346
 347  err_free:
 348         kfree(sta->ampdu_mlme.tid_tx[tid]);
 349         sta->ampdu_mlme.tid_tx[tid] = NULL;
 350  err_wake_queue:
 351         ieee80211_wake_queue_by_reason(
 352                 &local->hw, ieee80211_ac_from_tid(tid),
 353                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 354  err_unlock_sta:
 355         spin_unlock(&local->ampdu_lock);
 356         spin_unlock_bh(&sta->lock);
 357         return ret;
 358 }
 359 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 360
 361 /*
 362  * splice packets from the STA's pending to the local pending,
 363  * requires a call to ieee80211_agg_splice_finish and holding
 364  * local->ampdu_lock across both calls.
 365  */
 366 static void ieee80211_agg_splice_packets(struct ieee80211_local *local,
 367                                          struct sta_info *sta, u16 tid)
 368 {
 369         unsigned long flags;
 370         u16 queue = ieee80211_ac_from_tid(tid);
 371
 372         ieee80211_stop_queue_by_reason(
 373                 &local->hw, queue,
 374                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 375
 376         if (!(sta->ampdu_mlme.tid_state_tx[tid] & HT_ADDBA_REQUESTED_MSK))
 377                 return;
 378
 379         if (WARN(!sta->ampdu_mlme.tid_tx[tid],
 380                  "TID %d gone but expected when splicing aggregates from"
 381                  "the pending queue\n", tid))
 382                 return;
 383
 384         if (!skb_queue_empty(&sta->ampdu_mlme.tid_tx[tid]->pending)) {
 385                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 386                 /* copy over remaining packets */
 387                 skb_queue_splice_tail_init(
 388                         &sta->ampdu_mlme.tid_tx[tid]->pending,
 389                         &local->pending[queue]);
 390                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 391         }
 392 }
 393
 394 static void ieee80211_agg_splice_finish(struct ieee80211_local *local,
 395                                         struct sta_info *sta, u16 tid)
 396 {
 397         u16 queue = ieee80211_ac_from_tid(tid);
 398
 399         ieee80211_wake_queue_by_reason(
 400                 &local->hw, queue,
 401                 IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 402 }
 403
 404 /* caller must hold sta->lock */
 405 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 406                                          struct sta_info *sta, u16 tid)
 407 {
 408 #ifdef CONFIG_MAC80211_HT_DEBUG
 409         printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
 410 #endif
 411
 412         spin_lock(&local->ampdu_lock);
 413         ieee80211_agg_splice_packets(local, sta, tid);
 414         /*
 415          * NB: we rely on sta->lock being taken in the TX
 416          * processing here when adding to the pending queue,
 417          * otherwise we could only change the state of the
 418          * session to OPERATIONAL _here_.
 419          */
 420         ieee80211_agg_splice_finish(local, sta, tid);
 421         spin_unlock(&local->ampdu_lock);
 422
 423         drv_ampdu_action(local, &sta->sdata->vif,
 424                          IEEE80211_AMPDU_TX_OPERATIONAL,
 425                          &sta->sta, tid, NULL);
 426 }
 427
 428 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 429 {
 430         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 431         struct ieee80211_local *local = sdata->local;
 432         struct sta_info *sta;
 433         u8 *state;
 434
 435         if (tid >= STA_TID_NUM) {
 436 #ifdef CONFIG_MAC80211_HT_DEBUG
 437                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 438                                 tid, STA_TID_NUM);
 439 #endif
 440                 return;
 441         }
 442
 443         rcu_read_lock();
 444         sta = sta_info_get(local, ra);
 445         if (!sta) {
 446                 rcu_read_unlock();
 447 #ifdef CONFIG_MAC80211_HT_DEBUG
 448                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 449 #endif
 450                 return;
 451         }
 452
 453         state = &sta->ampdu_mlme.tid_state_tx[tid];
 454         spin_lock_bh(&sta->lock);
 455
 456         if (WARN_ON(!(*state & HT_ADDBA_REQUESTED_MSK))) {
 457 #ifdef CONFIG_MAC80211_HT_DEBUG
 458                 printk(KERN_DEBUG "addBA was not requested yet, state is %d\n",
 459                                 *state);
 460 #endif
 461                 spin_unlock_bh(&sta->lock);
 462                 rcu_read_unlock();
 463                 return;
 464         }
 465
 466         if (WARN_ON(*state & HT_ADDBA_DRV_READY_MSK))
 467                 goto out;
 468
 469         *state |= HT_ADDBA_DRV_READY_MSK;
 470
 471         if (*state == HT_AGG_STATE_OPERATIONAL)
 472                 ieee80211_agg_tx_operational(local, sta, tid);
 473
 474  out:
 475         spin_unlock_bh(&sta->lock);
 476         rcu_read_unlock();
 477 }
 478 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb);
 479
 480 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 481                                       const u8 *ra, u16 tid)
 482 {
 483         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 484         struct ieee80211_local *local = sdata->local;
 485         struct ieee80211_ra_tid *ra_tid;
 486         struct sk_buff *skb = dev_alloc_skb(0);
 487
 488         if (unlikely(!skb)) {
 489 #ifdef CONFIG_MAC80211_HT_DEBUG
 490                 if (net_ratelimit())
 491                         printk(KERN_WARNING "%s: Not enough memory, "
 492                                "dropping start BA session", skb->dev->name);
 493 #endif
 494                 return;
 495         }
 496         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 497         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 498         ra_tid->tid = tid;
 499         ra_tid->vif = vif;
 500
 501         skb->pkt_type = IEEE80211_ADDBA_MSG;
 502         skb_queue_tail(&local->skb_queue, skb);
 503         tasklet_schedule(&local->tasklet);
 504 }
 505 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 506
 507 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 508                                    enum ieee80211_back_parties initiator)
 509 {
 510         u8 *state;
 511         int ret;
 512
 513         /* check if the TID is in aggregation */
 514         state = &sta->ampdu_mlme.tid_state_tx[tid];
 515         spin_lock_bh(&sta->lock);
 516
 517         if (*state != HT_AGG_STATE_OPERATIONAL) {
 518                 ret = -ENOENT;
 519                 goto unlock;
 520         }
 521
 522         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator);
 523
 524  unlock:
 525         spin_unlock_bh(&sta->lock);
 526         return ret;
 527 }
 528
 529 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 530                                  enum ieee80211_back_parties initiator)
 531 {
 532         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 533         struct ieee80211_sub_if_data *sdata = sta->sdata;
 534         struct ieee80211_local *local = sdata->local;
 535
 536         if (!local->ops->ampdu_action)
 537                 return -EINVAL;
 538
 539         if (tid >= STA_TID_NUM)
 540                 return -EINVAL;
 541
 542         return __ieee80211_stop_tx_ba_session(sta, tid, initiator);
 543 }
 544 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 545
 546 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 547 {
 548         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 549         struct ieee80211_local *local = sdata->local;
 550         struct sta_info *sta;
 551         u8 *state;
 552
 553         if (tid >= STA_TID_NUM) {
 554 #ifdef CONFIG_MAC80211_HT_DEBUG
 555                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 556                                 tid, STA_TID_NUM);
 557 #endif
 558                 return;
 559         }
 560
 561 #ifdef CONFIG_MAC80211_HT_DEBUG
 562         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 563                ra, tid);
 564 #endif /* CONFIG_MAC80211_HT_DEBUG */
 565
 566         rcu_read_lock();
 567         sta = sta_info_get(local, ra);
 568         if (!sta) {
 569 #ifdef CONFIG_MAC80211_HT_DEBUG
 570                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 571 #endif
 572                 rcu_read_unlock();
 573                 return;
 574         }
 575         state = &sta->ampdu_mlme.tid_state_tx[tid];
 576
 577         /* NOTE: no need to use sta->lock in this state check, as
 578          * ieee80211_stop_tx_ba_session will let only one stop call to
 579          * pass through per sta/tid
 580          */
 581         if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) {
 582 #ifdef CONFIG_MAC80211_HT_DEBUG
 583                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 584 #endif
 585                 rcu_read_unlock();
 586                 return;
 587         }
 588
 589         if (*state & HT_AGG_STATE_INITIATOR_MSK)
 590                 ieee80211_send_delba(sta->sdata, ra, tid,
 591                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 592
 593         spin_lock_bh(&sta->lock);
 594         spin_lock(&local->ampdu_lock);
 595
 596         ieee80211_agg_splice_packets(local, sta, tid);
 597
 598         *state = HT_AGG_STATE_IDLE;
 599         /* from now on packets are no longer put onto sta->pending */
 600         kfree(sta->ampdu_mlme.tid_tx[tid]);
 601         sta->ampdu_mlme.tid_tx[tid] = NULL;
 602
 603         ieee80211_agg_splice_finish(local, sta, tid);
 604
 605         spin_unlock(&local->ampdu_lock);
 606         spin_unlock_bh(&sta->lock);
 607
 608         rcu_read_unlock();
 609 }
 610 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb);
 611
 612 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 613                                      const u8 *ra, u16 tid)
 614 {
 615         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 616         struct ieee80211_local *local = sdata->local;
 617         struct ieee80211_ra_tid *ra_tid;
 618         struct sk_buff *skb = dev_alloc_skb(0);
 619
 620         if (unlikely(!skb)) {
 621 #ifdef CONFIG_MAC80211_HT_DEBUG
 622                 if (net_ratelimit())
 623                         printk(KERN_WARNING "%s: Not enough memory, "
 624                                "dropping stop BA session", skb->dev->name);
 625 #endif
 626                 return;
 627         }
 628         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 629         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 630         ra_tid->tid = tid;
 631         ra_tid->vif = vif;
 632
 633         skb->pkt_type = IEEE80211_DELBA_MSG;
 634         skb_queue_tail(&local->skb_queue, skb);
 635         tasklet_schedule(&local->tasklet);
 636 }
 637 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 638
 639
 640 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 641                                   struct sta_info *sta,
 642                                   struct ieee80211_mgmt *mgmt,
 643                                   size_t len)
 644 {
 645         u16 capab, tid;
 646         u8 *state;
 647
 648         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 649         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 650
 651         state = &sta->ampdu_mlme.tid_state_tx[tid];
 652
 653         spin_lock_bh(&sta->lock);
 654
 655         if (!(*state & HT_ADDBA_REQUESTED_MSK))
 656                 goto out;
 657
 658         if (mgmt->u.action.u.addba_resp.dialog_token !=
 659                 sta->ampdu_mlme.tid_tx[tid]->dialog_token) {
 660 #ifdef CONFIG_MAC80211_HT_DEBUG
 661                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 662 #endif /* CONFIG_MAC80211_HT_DEBUG */
 663                 goto out;
 664         }
 665
 666         del_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
 667
 668 #ifdef CONFIG_MAC80211_HT_DEBUG
 669         printk(KERN_DEBUG "switched off addBA timer for tid %d \n", tid);
 670 #endif /* CONFIG_MAC80211_HT_DEBUG */
 671
 672         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 673                         == WLAN_STATUS_SUCCESS) {
 674                 u8 curstate = *state;
 675
 676                 *state |= HT_ADDBA_RECEIVED_MSK;
 677
 678                 if (*state != curstate && *state == HT_AGG_STATE_OPERATIONAL)
 679                         ieee80211_agg_tx_operational(local, sta, tid);
 680
 681                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 682         } else {
 683                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 684         }
 685
 686  out:
 687         spin_unlock_bh(&sta->lock);
 688 }