net/mac80211/agg-tx.c

   1 /*
   2  * HT handling
   3  *
   4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5  * Copyright 2002-2005, Instant802 Networks, Inc.
   6  * Copyright 2005-2006, Devicescape Software, Inc.
   7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9  * Copyright 2007-2010, Intel Corporation
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/ieee80211.h>
  17 #include <linux/slab.h>
  18 #include <net/mac80211.h>
  19 #include "ieee80211_i.h"
  20 #include "driver-ops.h"
  21 #include "wme.h"
  22
  23 /**
  24  * DOC: TX A-MPDU aggregation
  25  *
  26  * Aggregation on the TX side requires setting the hardware flag
  27  * %IEEE80211_HW_AMPDU_AGGREGATION. The driver will then be handed
  28  * packets with a flag indicating A-MPDU aggregation. The driver
  29  * or device is responsible for actually aggregating the frames,
  30  * as well as deciding how many and which to aggregate.
  31  *
  32  * When TX aggregation is started by some subsystem (usually the rate
  33  * control algorithm would be appropriate) by calling the
  34  * ieee80211_start_tx_ba_session() function, the driver will be
  35  * notified via its @ampdu_action function, with the
  36  * %IEEE80211_AMPDU_TX_START action.
  37  *
  38  * In response to that, the driver is later required to call the
  39  * ieee80211_start_tx_ba_cb_irqsafe() function, which will really
  40  * start the aggregation session after the peer has also responded.
  41  * If the peer responds negatively, the session will be stopped
  42  * again right away. Note that it is possible for the aggregation
  43  * session to be stopped before the driver has indicated that it
  44  * is done setting it up, in which case it must not indicate the
  45  * setup completion.
  46  *
  47  * Also note that, since we also need to wait for a response from
  48  * the peer, the driver is notified of the completion of the
  49  * handshake by the %IEEE80211_AMPDU_TX_OPERATIONAL action to the
  50  * @ampdu_action callback.
  51  *
  52  * Similarly, when the aggregation session is stopped by the peer
  53  * or something calling ieee80211_stop_tx_ba_session(), the driver's
  54  * @ampdu_action function will be called with the action
  55  * %IEEE80211_AMPDU_TX_STOP. In this case, the call must not fail,
  56  * and the driver must later call ieee80211_stop_tx_ba_cb_irqsafe().
  57  */
  58
  59 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
  60                                          const u8 *da, u16 tid,
  61                                          u8 dialog_token, u16 start_seq_num,
  62                                          u16 agg_size, u16 timeout)
  63 {
  64         struct ieee80211_local *local = sdata->local;
  65         struct sk_buff *skb;
  66         struct ieee80211_mgmt *mgmt;
  67         u16 capab;
  68
  69         skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
  70
  71         if (!skb) {
  72                 printk(KERN_ERR "%s: failed to allocate buffer "
  73                                 "for addba request frame\n", sdata->name);
  74                 return;
  75         }
  76         skb_reserve(skb, local->hw.extra_tx_headroom);
  77         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
  78         memset(mgmt, 0, 24);
  79         memcpy(mgmt->da, da, ETH_ALEN);
  80         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
  81         if (sdata->vif.type == NL80211_IFTYPE_AP ||
  82             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
  83                 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
  84         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
  85                 memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
  86
  87         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  88                                           IEEE80211_STYPE_ACTION);
  89
  90         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
  91
  92         mgmt->u.action.category = WLAN_CATEGORY_BACK;
  93         mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
  94
  95         mgmt->u.action.u.addba_req.dialog_token = dialog_token;
  96         capab = (u16)(1 << 1);          /* bit 1 aggregation policy */
  97         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
  98         capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
  99
 100         mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
 101
 102         mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
 103         mgmt->u.action.u.addba_req.start_seq_num =
 104                                         cpu_to_le16(start_seq_num << 4);
 105
 106         ieee80211_tx_skb(sdata, skb);
 107 }
 108
 109 void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u16 ssn)
 110 {
 111         struct ieee80211_local *local = sdata->local;
 112         struct sk_buff *skb;
 113         struct ieee80211_bar *bar;
 114         u16 bar_control = 0;
 115
 116         skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
 117         if (!skb) {
 118                 printk(KERN_ERR "%s: failed to allocate buffer for "
 119                         "bar frame\n", sdata->name);
 120                 return;
 121         }
 122         skb_reserve(skb, local->hw.extra_tx_headroom);
 123         bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
 124         memset(bar, 0, sizeof(*bar));
 125         bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
 126                                          IEEE80211_STYPE_BACK_REQ);
 127         memcpy(bar->ra, ra, ETH_ALEN);
 128         memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
 129         bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 130         bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
 131         bar_control |= (u16)(tid << 12);
 132         bar->control = cpu_to_le16(bar_control);
 133         bar->start_seq_num = cpu_to_le16(ssn);
 134
 135         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 136         ieee80211_tx_skb(sdata, skb);
 137 }
 138
 139 static void kfree_tid_tx(struct rcu_head *rcu_head)
 140 {
 141         struct tid_ampdu_tx *tid_tx =
 142             container_of(rcu_head, struct tid_ampdu_tx, rcu_head);
 143
 144         kfree(tid_tx);
 145 }
 146
 147 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 148                                     enum ieee80211_back_parties initiator)
 149 {
 150         struct ieee80211_local *local = sta->local;
 151         struct tid_ampdu_tx *tid_tx = sta->ampdu_mlme.tid_tx[tid];
 152         int ret;
 153
 154         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 155
 156         if (!tid_tx)
 157                 return -ENOENT;
 158
 159         spin_lock_bh(&sta->lock);
 160
 161         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 162                 /* not even started yet! */
 163                 rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
 164                 spin_unlock_bh(&sta->lock);
 165                 call_rcu(&tid_tx->rcu_head, kfree_tid_tx);
 166                 return 0;
 167         }
 168
 169         spin_unlock_bh(&sta->lock);
 170
 171 #ifdef CONFIG_MAC80211_HT_DEBUG
 172         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 173                sta->sta.addr, tid);
 174 #endif /* CONFIG_MAC80211_HT_DEBUG */
 175
 176         set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 177
 178         /*
 179          * After this packets are no longer handed right through
 180          * to the driver but are put onto tid_tx->pending instead,
 181          * with locking to ensure proper access.
 182          */
 183         clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 184
 185         tid_tx->stop_initiator = initiator;
 186
 187         ret = drv_ampdu_action(local, sta->sdata,
 188                                IEEE80211_AMPDU_TX_STOP,
 189                                &sta->sta, tid, NULL);
 190
 191         /* HW shall not deny going back to legacy */
 192         if (WARN_ON(ret)) {
 193                 /*
 194                  * We may have pending packets get stuck in this case...
 195                  * Not bothering with a workaround for now.
 196                  */
 197         }
 198
 199         return ret;
 200 }
 201
 202 /*
 203  * After sending add Block Ack request we activated a timer until
 204  * add Block Ack response will arrive from the recipient.
 205  * If this timer expires sta_addba_resp_timer_expired will be executed.
 206  */
 207 static void sta_addba_resp_timer_expired(unsigned long data)
 208 {
 209         /* not an elegant detour, but there is no choice as the timer passes
 210          * only one argument, and both sta_info and TID are needed, so init
 211          * flow in sta_info_create gives the TID as data, while the timer_to_id
 212          * array gives the sta through container_of */
 213         u16 tid = *(u8 *)data;
 214         struct sta_info *sta = container_of((void *)data,
 215                 struct sta_info, timer_to_tid[tid]);
 216         struct tid_ampdu_tx *tid_tx;
 217
 218         /* check if the TID waits for addBA response */
 219         rcu_read_lock();
 220         tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 221         if (!tid_tx ||
 222             test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 223                 rcu_read_unlock();
 224 #ifdef CONFIG_MAC80211_HT_DEBUG
 225                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 226                                 "(or no longer) expecting addBA response there\n",
 227                         tid);
 228 #endif
 229                 return;
 230         }
 231
 232 #ifdef CONFIG_MAC80211_HT_DEBUG
 233         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 234 #endif
 235
 236         ieee80211_stop_tx_ba_session(&sta->sta, tid);
 237         rcu_read_unlock();
 238 }
 239
 240 static inline int ieee80211_ac_from_tid(int tid)
 241 {
 242         return ieee802_1d_to_ac[tid & 7];
 243 }
 244
 245 /*
 246  * When multiple aggregation sessions on multiple stations
 247  * are being created/destroyed simultaneously, we need to
 248  * refcount the global queue stop caused by that in order
 249  * to not get into a situation where one of the aggregation
 250  * setup or teardown re-enables queues before the other is
 251  * ready to handle that.
 252  *
 253  * These two functions take care of this issue by keeping
 254  * a global "agg_queue_stop" refcount.
 255  */
 256 static void __acquires(agg_queue)
 257 ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
 258 {
 259         int queue = ieee80211_ac_from_tid(tid);
 260
 261         if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
 262                 ieee80211_stop_queue_by_reason(
 263                         &local->hw, queue,
 264                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 265         __acquire(agg_queue);
 266 }
 267
 268 static void __releases(agg_queue)
 269 ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 270 {
 271         int queue = ieee80211_ac_from_tid(tid);
 272
 273         if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
 274                 ieee80211_wake_queue_by_reason(
 275                         &local->hw, queue,
 276                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 277         __release(agg_queue);
 278 }
 279
 280 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 281 {
 282         struct tid_ampdu_tx *tid_tx = sta->ampdu_mlme.tid_tx[tid];
 283         struct ieee80211_local *local = sta->local;
 284         struct ieee80211_sub_if_data *sdata = sta->sdata;
 285         u16 start_seq_num;
 286         int ret;
 287
 288         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 289
 290         /*
 291          * While we're asking the driver about the aggregation,
 292          * stop the AC queue so that we don't have to worry
 293          * about frames that came in while we were doing that,
 294          * which would require us to put them to the AC pending
 295          * afterwards which just makes the code more complex.
 296          */
 297         ieee80211_stop_queue_agg(local, tid);
 298
 299         clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 300
 301         /*
 302          * make sure no packets are being processed to get
 303          * valid starting sequence number
 304          */
 305         synchronize_net();
 306
 307         start_seq_num = sta->tid_seq[tid] >> 4;
 308
 309         ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 310                                &sta->sta, tid, &start_seq_num);
 311         if (ret) {
 312 #ifdef CONFIG_MAC80211_HT_DEBUG
 313                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 314                                         " tid %d\n", tid);
 315 #endif
 316                 spin_lock_bh(&sta->lock);
 317                 rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
 318                 spin_unlock_bh(&sta->lock);
 319
 320                 ieee80211_wake_queue_agg(local, tid);
 321                 call_rcu(&tid_tx->rcu_head, kfree_tid_tx);
 322                 return;
 323         }
 324
 325         /* we can take packets again now */
 326         ieee80211_wake_queue_agg(local, tid);
 327
 328         /* activate the timer for the recipient's addBA response */
 329         mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 330 #ifdef CONFIG_MAC80211_HT_DEBUG
 331         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 332 #endif
 333
 334         spin_lock_bh(&sta->lock);
 335         sta->ampdu_mlme.addba_req_num[tid]++;
 336         spin_unlock_bh(&sta->lock);
 337
 338         /* send AddBA request */
 339         ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 340                                      tid_tx->dialog_token, start_seq_num,
 341                                      0x40, 5000);
 342 }
 343
 344 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 345 {
 346         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 347         struct ieee80211_sub_if_data *sdata = sta->sdata;
 348         struct ieee80211_local *local = sdata->local;
 349         struct tid_ampdu_tx *tid_tx;
 350         int ret = 0;
 351
 352         trace_api_start_tx_ba_session(pubsta, tid);
 353
 354         if (WARN_ON(!local->ops->ampdu_action))
 355                 return -EINVAL;
 356
 357         if ((tid >= STA_TID_NUM) ||
 358             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION))
 359                 return -EINVAL;
 360
 361 #ifdef CONFIG_MAC80211_HT_DEBUG
 362         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 363                pubsta->addr, tid);
 364 #endif /* CONFIG_MAC80211_HT_DEBUG */
 365
 366         /*
 367          * The aggregation code is not prepared to handle
 368          * anything but STA/AP due to the BSSID handling.
 369          * IBSS could work in the code but isn't supported
 370          * by drivers or the standard.
 371          */
 372         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 373             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 374             sdata->vif.type != NL80211_IFTYPE_AP)
 375                 return -EINVAL;
 376
 377         if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
 378 #ifdef CONFIG_MAC80211_HT_DEBUG
 379                 printk(KERN_DEBUG "BA sessions blocked. "
 380                        "Denying BA session request\n");
 381 #endif
 382                 return -EINVAL;
 383         }
 384
 385         spin_lock_bh(&sta->lock);
 386
 387         /* we have tried too many times, receiver does not want A-MPDU */
 388         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 389                 ret = -EBUSY;
 390                 goto err_unlock_sta;
 391         }
 392
 393         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 394         /* check if the TID is not in aggregation flow already */
 395         if (tid_tx) {
 396 #ifdef CONFIG_MAC80211_HT_DEBUG
 397                 printk(KERN_DEBUG "BA request denied - session is not "
 398                                  "idle on tid %u\n", tid);
 399 #endif /* CONFIG_MAC80211_HT_DEBUG */
 400                 ret = -EAGAIN;
 401                 goto err_unlock_sta;
 402         }
 403
 404         /* prepare A-MPDU MLME for Tx aggregation */
 405         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 406         if (!tid_tx) {
 407 #ifdef CONFIG_MAC80211_HT_DEBUG
 408                 if (net_ratelimit())
 409                         printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
 410                                         tid);
 411 #endif
 412                 ret = -ENOMEM;
 413                 goto err_unlock_sta;
 414         }
 415
 416         skb_queue_head_init(&tid_tx->pending);
 417         __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 418
 419         /* Tx timer */
 420         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 421         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 422         init_timer(&tid_tx->addba_resp_timer);
 423
 424         /* assign a dialog token */
 425         sta->ampdu_mlme.dialog_token_allocator++;
 426         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 427
 428         /* finally, assign it to the array */
 429         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 430
 431         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 432
 433         /* this flow continues off the work */
 434  err_unlock_sta:
 435         spin_unlock_bh(&sta->lock);
 436         return ret;
 437 }
 438 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 439
 440 /*
 441  * splice packets from the STA's pending to the local pending,
 442  * requires a call to ieee80211_agg_splice_finish later
 443  */
 444 static void __acquires(agg_queue)
 445 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 446                              struct tid_ampdu_tx *tid_tx, u16 tid)
 447 {
 448         int queue = ieee80211_ac_from_tid(tid);
 449         unsigned long flags;
 450
 451         ieee80211_stop_queue_agg(local, tid);
 452
 453         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 454                           " from the pending queue\n", tid))
 455                 return;
 456
 457         if (!skb_queue_empty(&tid_tx->pending)) {
 458                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 459                 /* copy over remaining packets */
 460                 skb_queue_splice_tail_init(&tid_tx->pending,
 461                                            &local->pending[queue]);
 462                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 463         }
 464 }
 465
 466 static void __releases(agg_queue)
 467 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 468 {
 469         ieee80211_wake_queue_agg(local, tid);
 470 }
 471
 472 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 473                                          struct sta_info *sta, u16 tid)
 474 {
 475         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 476
 477 #ifdef CONFIG_MAC80211_HT_DEBUG
 478         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 479 #endif
 480
 481         drv_ampdu_action(local, sta->sdata,
 482                          IEEE80211_AMPDU_TX_OPERATIONAL,
 483                          &sta->sta, tid, NULL);
 484
 485         /*
 486          * synchronize with TX path, while splicing the TX path
 487          * should block so it won't put more packets onto pending.
 488          */
 489         spin_lock_bh(&sta->lock);
 490
 491         ieee80211_agg_splice_packets(local, sta->ampdu_mlme.tid_tx[tid], tid);
 492         /*
 493          * Now mark as operational. This will be visible
 494          * in the TX path, and lets it go lock-free in
 495          * the common case.
 496          */
 497         set_bit(HT_AGG_STATE_OPERATIONAL, &sta->ampdu_mlme.tid_tx[tid]->state);
 498         ieee80211_agg_splice_finish(local, tid);
 499
 500         spin_unlock_bh(&sta->lock);
 501 }
 502
 503 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 504 {
 505         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 506         struct ieee80211_local *local = sdata->local;
 507         struct sta_info *sta;
 508         struct tid_ampdu_tx *tid_tx;
 509
 510         trace_api_start_tx_ba_cb(sdata, ra, tid);
 511
 512         if (tid >= STA_TID_NUM) {
 513 #ifdef CONFIG_MAC80211_HT_DEBUG
 514                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 515                                 tid, STA_TID_NUM);
 516 #endif
 517                 return;
 518         }
 519
 520         mutex_lock(&local->sta_mtx);
 521         sta = sta_info_get(sdata, ra);
 522         if (!sta) {
 523                 mutex_unlock(&local->sta_mtx);
 524 #ifdef CONFIG_MAC80211_HT_DEBUG
 525                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 526 #endif
 527                 return;
 528         }
 529
 530         mutex_lock(&sta->ampdu_mlme.mtx);
 531         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 532
 533         if (WARN_ON(!tid_tx)) {
 534 #ifdef CONFIG_MAC80211_HT_DEBUG
 535                 printk(KERN_DEBUG "addBA was not requested!\n");
 536 #endif
 537                 goto unlock;
 538         }
 539
 540         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 541                 goto unlock;
 542
 543         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 544                 ieee80211_agg_tx_operational(local, sta, tid);
 545
 546  unlock:
 547         mutex_unlock(&sta->ampdu_mlme.mtx);
 548         mutex_unlock(&local->sta_mtx);
 549 }
 550
 551 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 552                                       const u8 *ra, u16 tid)
 553 {
 554         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 555         struct ieee80211_local *local = sdata->local;
 556         struct ieee80211_ra_tid *ra_tid;
 557         struct sk_buff *skb = dev_alloc_skb(0);
 558
 559         if (unlikely(!skb)) {
 560 #ifdef CONFIG_MAC80211_HT_DEBUG
 561                 if (net_ratelimit())
 562                         printk(KERN_WARNING "%s: Not enough memory, "
 563                                "dropping start BA session", sdata->name);
 564 #endif
 565                 return;
 566         }
 567         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 568         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 569         ra_tid->tid = tid;
 570
 571         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 572         skb_queue_tail(&sdata->skb_queue, skb);
 573         ieee80211_queue_work(&local->hw, &sdata->work);
 574 }
 575 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 576
 577 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 578                                    enum ieee80211_back_parties initiator)
 579 {
 580         int ret;
 581
 582         mutex_lock(&sta->ampdu_mlme.mtx);
 583
 584         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator);
 585
 586         mutex_unlock(&sta->ampdu_mlme.mtx);
 587
 588         return ret;
 589 }
 590
 591 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 592 {
 593         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 594         struct ieee80211_sub_if_data *sdata = sta->sdata;
 595         struct ieee80211_local *local = sdata->local;
 596         struct tid_ampdu_tx *tid_tx;
 597         int ret = 0;
 598
 599         trace_api_stop_tx_ba_session(pubsta, tid);
 600
 601         if (!local->ops->ampdu_action)
 602                 return -EINVAL;
 603
 604         if (tid >= STA_TID_NUM)
 605                 return -EINVAL;
 606
 607         spin_lock_bh(&sta->lock);
 608         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 609
 610         if (!tid_tx) {
 611                 ret = -ENOENT;
 612                 goto unlock;
 613         }
 614
 615         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 616                 /* already in progress stopping it */
 617                 ret = 0;
 618                 goto unlock;
 619         }
 620
 621         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 622         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 623
 624  unlock:
 625         spin_unlock_bh(&sta->lock);
 626         return ret;
 627 }
 628 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 629
 630 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 631 {
 632         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 633         struct ieee80211_local *local = sdata->local;
 634         struct sta_info *sta;
 635         struct tid_ampdu_tx *tid_tx;
 636
 637         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 638
 639         if (tid >= STA_TID_NUM) {
 640 #ifdef CONFIG_MAC80211_HT_DEBUG
 641                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 642                                 tid, STA_TID_NUM);
 643 #endif
 644                 return;
 645         }
 646
 647 #ifdef CONFIG_MAC80211_HT_DEBUG
 648         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 649                ra, tid);
 650 #endif /* CONFIG_MAC80211_HT_DEBUG */
 651
 652         mutex_lock(&local->sta_mtx);
 653
 654         sta = sta_info_get(sdata, ra);
 655         if (!sta) {
 656 #ifdef CONFIG_MAC80211_HT_DEBUG
 657                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 658 #endif
 659                 goto unlock;
 660         }
 661
 662         mutex_lock(&sta->ampdu_mlme.mtx);
 663         spin_lock_bh(&sta->lock);
 664         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 665
 666         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 667 #ifdef CONFIG_MAC80211_HT_DEBUG
 668                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 669 #endif
 670                 goto unlock_sta;
 671         }
 672
 673         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR)
 674                 ieee80211_send_delba(sta->sdata, ra, tid,
 675                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 676
 677         /*
 678          * When we get here, the TX path will not be lockless any more wrt.
 679          * aggregation, since the OPERATIONAL bit has long been cleared.
 680          * Thus it will block on getting the lock, if it occurs. So if we
 681          * stop the queue now, we will not get any more packets, and any
 682          * that might be being processed will wait for us here, thereby
 683          * guaranteeing that no packets go to the tid_tx pending queue any
 684          * more.
 685          */
 686
 687         ieee80211_agg_splice_packets(local, tid_tx, tid);
 688
 689         /* future packets must not find the tid_tx struct any more */
 690         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
 691
 692         ieee80211_agg_splice_finish(local, tid);
 693
 694         call_rcu(&tid_tx->rcu_head, kfree_tid_tx);
 695
 696  unlock_sta:
 697         spin_unlock_bh(&sta->lock);
 698         mutex_unlock(&sta->ampdu_mlme.mtx);
 699  unlock:
 700         mutex_unlock(&local->sta_mtx);
 701 }
 702
 703 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 704                                      const u8 *ra, u16 tid)
 705 {
 706         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 707         struct ieee80211_local *local = sdata->local;
 708         struct ieee80211_ra_tid *ra_tid;
 709         struct sk_buff *skb = dev_alloc_skb(0);
 710
 711         if (unlikely(!skb)) {
 712 #ifdef CONFIG_MAC80211_HT_DEBUG
 713                 if (net_ratelimit())
 714                         printk(KERN_WARNING "%s: Not enough memory, "
 715                                "dropping stop BA session", sdata->name);
 716 #endif
 717                 return;
 718         }
 719         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 720         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 721         ra_tid->tid = tid;
 722
 723         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 724         skb_queue_tail(&sdata->skb_queue, skb);
 725         ieee80211_queue_work(&local->hw, &sdata->work);
 726 }
 727 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 728
 729
 730 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 731                                   struct sta_info *sta,
 732                                   struct ieee80211_mgmt *mgmt,
 733                                   size_t len)
 734 {
 735         struct tid_ampdu_tx *tid_tx;
 736         u16 capab, tid;
 737
 738         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 739         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 740
 741         mutex_lock(&sta->ampdu_mlme.mtx);
 742
 743         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 744         if (!tid_tx)
 745                 goto out;
 746
 747         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 748 #ifdef CONFIG_MAC80211_HT_DEBUG
 749                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 750 #endif
 751                 goto out;
 752         }
 753
 754         del_timer(&tid_tx->addba_resp_timer);
 755
 756 #ifdef CONFIG_MAC80211_HT_DEBUG
 757         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 758 #endif
 759
 760         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 761                         == WLAN_STATUS_SUCCESS) {
 762                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 763                                      &tid_tx->state)) {
 764                         /* ignore duplicate response */
 765                         goto out;
 766                 }
 767
 768                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 769                         ieee80211_agg_tx_operational(local, sta, tid);
 770
 771                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 772         } else {
 773                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 774         }
 775
 776  out:
 777         mutex_unlock(&sta->ampdu_mlme.mtx);
 778 }