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