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 <linux/export.h>
  19 #include <net/mac80211.h>
  20 #include "ieee80211_i.h"
  21 #include "driver-ops.h"
  22 #include "wme.h"
  23
  24 /**
  25  * DOC: TX A-MPDU aggregation
  26  *
  27  * Aggregation on the TX side requires setting the hardware flag
  28  * %IEEE80211_HW_AMPDU_AGGREGATION. The driver will then be handed
  29  * packets with a flag indicating A-MPDU aggregation. The driver
  30  * or device is responsible for actually aggregating the frames,
  31  * as well as deciding how many and which to aggregate.
  32  *
  33  * When TX aggregation is started by some subsystem (usually the rate
  34  * control algorithm would be appropriate) by calling the
  35  * ieee80211_start_tx_ba_session() function, the driver will be
  36  * notified via its @ampdu_action function, with the
  37  * %IEEE80211_AMPDU_TX_START action.
  38  *
  39  * In response to that, the driver is later required to call the
  40  * ieee80211_start_tx_ba_cb_irqsafe() function, which will really
  41  * start the aggregation session after the peer has also responded.
  42  * If the peer responds negatively, the session will be stopped
  43  * again right away. Note that it is possible for the aggregation
  44  * session to be stopped before the driver has indicated that it
  45  * is done setting it up, in which case it must not indicate the
  46  * setup completion.
  47  *
  48  * Also note that, since we also need to wait for a response from
  49  * the peer, the driver is notified of the completion of the
  50  * handshake by the %IEEE80211_AMPDU_TX_OPERATIONAL action to the
  51  * @ampdu_action callback.
  52  *
  53  * Similarly, when the aggregation session is stopped by the peer
  54  * or something calling ieee80211_stop_tx_ba_session(), the driver's
  55  * @ampdu_action function will be called with the action
  56  * %IEEE80211_AMPDU_TX_STOP. In this case, the call must not fail,
  57  * and the driver must later call ieee80211_stop_tx_ba_cb_irqsafe().
  58  */
  59
  60 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
  61                                          const u8 *da, u16 tid,
  62                                          u8 dialog_token, u16 start_seq_num,
  63                                          u16 agg_size, u16 timeout)
  64 {
  65         struct ieee80211_local *local = sdata->local;
  66         struct sk_buff *skb;
  67         struct ieee80211_mgmt *mgmt;
  68         u16 capab;
  69
  70         skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
  71
  72         if (!skb)
  73                 return;
  74
  75         skb_reserve(skb, local->hw.extra_tx_headroom);
  76         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
  77         memset(mgmt, 0, 24);
  78         memcpy(mgmt->da, da, ETH_ALEN);
  79         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
  80         if (sdata->vif.type == NL80211_IFTYPE_AP ||
  81             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
  82                 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
  83         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
  84                 memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
  85
  86         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  87                                           IEEE80211_STYPE_ACTION);
  88
  89         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
  90
  91         mgmt->u.action.category = WLAN_CATEGORY_BACK;
  92         mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
  93
  94         mgmt->u.action.u.addba_req.dialog_token = dialog_token;
  95         capab = (u16)(1 << 1);          /* bit 1 aggregation policy */
  96         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
  97         capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
  98
  99         mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
 100
 101         mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
 102         mgmt->u.action.u.addba_req.start_seq_num =
 103                                         cpu_to_le16(start_seq_num << 4);
 104
 105         ieee80211_tx_skb(sdata, skb);
 106 }
 107
 108 void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
 109 {
 110         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 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                 return;
 119
 120         skb_reserve(skb, local->hw.extra_tx_headroom);
 121         bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
 122         memset(bar, 0, sizeof(*bar));
 123         bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
 124                                          IEEE80211_STYPE_BACK_REQ);
 125         memcpy(bar->ra, ra, ETH_ALEN);
 126         memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
 127         bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 128         bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
 129         bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
 130         bar->control = cpu_to_le16(bar_control);
 131         bar->start_seq_num = cpu_to_le16(ssn);
 132
 133         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 134         ieee80211_tx_skb(sdata, skb);
 135 }
 136 EXPORT_SYMBOL(ieee80211_send_bar);
 137
 138 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
 139                              struct tid_ampdu_tx *tid_tx)
 140 {
 141         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 142         lockdep_assert_held(&sta->lock);
 143         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 144 }
 145
 146 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 147                                     enum ieee80211_back_parties initiator,
 148                                     bool tx)
 149 {
 150         struct ieee80211_local *local = sta->local;
 151         struct tid_ampdu_tx *tid_tx;
 152         int ret;
 153
 154         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 155
 156         spin_lock_bh(&sta->lock);
 157
 158         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 159         if (!tid_tx) {
 160                 spin_unlock_bh(&sta->lock);
 161                 return -ENOENT;
 162         }
 163
 164         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 165                 /* not even started yet! */
 166                 ieee80211_assign_tid_tx(sta, tid, NULL);
 167                 spin_unlock_bh(&sta->lock);
 168                 kfree_rcu(tid_tx, rcu_head);
 169                 return 0;
 170         }
 171
 172         spin_unlock_bh(&sta->lock);
 173
 174 #ifdef CONFIG_MAC80211_HT_DEBUG
 175         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 176                sta->sta.addr, tid);
 177 #endif /* CONFIG_MAC80211_HT_DEBUG */
 178
 179         set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 180
 181         del_timer_sync(&tid_tx->addba_resp_timer);
 182
 183         /*
 184          * After this packets are no longer handed right through
 185          * to the driver but are put onto tid_tx->pending instead,
 186          * with locking to ensure proper access.
 187          */
 188         clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 189
 190         tid_tx->stop_initiator = initiator;
 191         tid_tx->tx_stop = tx;
 192
 193         ret = drv_ampdu_action(local, sta->sdata,
 194                                IEEE80211_AMPDU_TX_STOP,
 195                                &sta->sta, tid, NULL, 0);
 196
 197         /* HW shall not deny going back to legacy */
 198         if (WARN_ON(ret)) {
 199                 /*
 200                  * We may have pending packets get stuck in this case...
 201                  * Not bothering with a workaround for now.
 202                  */
 203         }
 204
 205         return ret;
 206 }
 207
 208 /*
 209  * After sending add Block Ack request we activated a timer until
 210  * add Block Ack response will arrive from the recipient.
 211  * If this timer expires sta_addba_resp_timer_expired will be executed.
 212  */
 213 static void sta_addba_resp_timer_expired(unsigned long data)
 214 {
 215         /* not an elegant detour, but there is no choice as the timer passes
 216          * only one argument, and both sta_info and TID are needed, so init
 217          * flow in sta_info_create gives the TID as data, while the timer_to_id
 218          * array gives the sta through container_of */
 219         u16 tid = *(u8 *)data;
 220         struct sta_info *sta = container_of((void *)data,
 221                 struct sta_info, timer_to_tid[tid]);
 222         struct tid_ampdu_tx *tid_tx;
 223
 224         /* check if the TID waits for addBA response */
 225         rcu_read_lock();
 226         tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 227         if (!tid_tx ||
 228             test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 229                 rcu_read_unlock();
 230 #ifdef CONFIG_MAC80211_HT_DEBUG
 231                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 232                                 "(or no longer) expecting addBA response there\n",
 233                         tid);
 234 #endif
 235                 return;
 236         }
 237
 238 #ifdef CONFIG_MAC80211_HT_DEBUG
 239         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 240 #endif
 241
 242         ieee80211_stop_tx_ba_session(&sta->sta, tid);
 243         rcu_read_unlock();
 244 }
 245
 246 static inline int ieee80211_ac_from_tid(int tid)
 247 {
 248         return ieee802_1d_to_ac[tid & 7];
 249 }
 250
 251 /*
 252  * When multiple aggregation sessions on multiple stations
 253  * are being created/destroyed simultaneously, we need to
 254  * refcount the global queue stop caused by that in order
 255  * to not get into a situation where one of the aggregation
 256  * setup or teardown re-enables queues before the other is
 257  * ready to handle that.
 258  *
 259  * These two functions take care of this issue by keeping
 260  * a global "agg_queue_stop" refcount.
 261  */
 262 static void __acquires(agg_queue)
 263 ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
 264 {
 265         int queue = ieee80211_ac_from_tid(tid);
 266
 267         if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
 268                 ieee80211_stop_queue_by_reason(
 269                         &local->hw, queue,
 270                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 271         __acquire(agg_queue);
 272 }
 273
 274 static void __releases(agg_queue)
 275 ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 276 {
 277         int queue = ieee80211_ac_from_tid(tid);
 278
 279         if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
 280                 ieee80211_wake_queue_by_reason(
 281                         &local->hw, queue,
 282                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 283         __release(agg_queue);
 284 }
 285
 286 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 287 {
 288         struct tid_ampdu_tx *tid_tx;
 289         struct ieee80211_local *local = sta->local;
 290         struct ieee80211_sub_if_data *sdata = sta->sdata;
 291         u16 start_seq_num;
 292         int ret;
 293
 294         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 295
 296         /*
 297          * While we're asking the driver about the aggregation,
 298          * stop the AC queue so that we don't have to worry
 299          * about frames that came in while we were doing that,
 300          * which would require us to put them to the AC pending
 301          * afterwards which just makes the code more complex.
 302          */
 303         ieee80211_stop_queue_agg(local, tid);
 304
 305         clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 306
 307         /*
 308          * make sure no packets are being processed to get
 309          * valid starting sequence number
 310          */
 311         synchronize_net();
 312
 313         start_seq_num = sta->tid_seq[tid] >> 4;
 314
 315         ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 316                                &sta->sta, tid, &start_seq_num, 0);
 317         if (ret) {
 318 #ifdef CONFIG_MAC80211_HT_DEBUG
 319                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 320                                         " tid %d\n", tid);
 321 #endif
 322                 spin_lock_bh(&sta->lock);
 323                 ieee80211_assign_tid_tx(sta, tid, NULL);
 324                 spin_unlock_bh(&sta->lock);
 325
 326                 ieee80211_wake_queue_agg(local, tid);
 327                 kfree_rcu(tid_tx, rcu_head);
 328                 return;
 329         }
 330
 331         /* we can take packets again now */
 332         ieee80211_wake_queue_agg(local, tid);
 333
 334         /* activate the timer for the recipient's addBA response */
 335         mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 336 #ifdef CONFIG_MAC80211_HT_DEBUG
 337         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 338 #endif
 339
 340         spin_lock_bh(&sta->lock);
 341         sta->ampdu_mlme.addba_req_num[tid]++;
 342         spin_unlock_bh(&sta->lock);
 343
 344         /* send AddBA request */
 345         ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 346                                      tid_tx->dialog_token, start_seq_num,
 347                                      local->hw.max_tx_aggregation_subframes,
 348                                      tid_tx->timeout);
 349 }
 350
 351 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 352                                   u16 timeout)
 353 {
 354         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 355         struct ieee80211_sub_if_data *sdata = sta->sdata;
 356         struct ieee80211_local *local = sdata->local;
 357         struct tid_ampdu_tx *tid_tx;
 358         int ret = 0;
 359
 360         trace_api_start_tx_ba_session(pubsta, tid);
 361
 362         if (WARN_ON(!local->ops->ampdu_action))
 363                 return -EINVAL;
 364
 365         if ((tid >= STA_TID_NUM) ||
 366             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION) ||
 367             (local->hw.flags & IEEE80211_HW_TX_AMPDU_SETUP_IN_HW))
 368                 return -EINVAL;
 369
 370 #ifdef CONFIG_MAC80211_HT_DEBUG
 371         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 372                pubsta->addr, tid);
 373 #endif /* CONFIG_MAC80211_HT_DEBUG */
 374
 375         /*
 376          * The aggregation code is not prepared to handle
 377          * anything but STA/AP due to the BSSID handling.
 378          * IBSS could work in the code but isn't supported
 379          * by drivers or the standard.
 380          */
 381         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 382             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 383             sdata->vif.type != NL80211_IFTYPE_AP)
 384                 return -EINVAL;
 385
 386         if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
 387 #ifdef CONFIG_MAC80211_HT_DEBUG
 388                 printk(KERN_DEBUG "BA sessions blocked. "
 389                        "Denying BA session request\n");
 390 #endif
 391                 return -EINVAL;
 392         }
 393
 394         spin_lock_bh(&sta->lock);
 395
 396         /* we have tried too many times, receiver does not want A-MPDU */
 397         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 398                 ret = -EBUSY;
 399                 goto err_unlock_sta;
 400         }
 401
 402         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 403         /* check if the TID is not in aggregation flow already */
 404         if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
 405 #ifdef CONFIG_MAC80211_HT_DEBUG
 406                 printk(KERN_DEBUG "BA request denied - session is not "
 407                                  "idle on tid %u\n", tid);
 408 #endif /* CONFIG_MAC80211_HT_DEBUG */
 409                 ret = -EAGAIN;
 410                 goto err_unlock_sta;
 411         }
 412
 413         /* prepare A-MPDU MLME for Tx aggregation */
 414         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 415         if (!tid_tx) {
 416                 ret = -ENOMEM;
 417                 goto err_unlock_sta;
 418         }
 419
 420         skb_queue_head_init(&tid_tx->pending);
 421         __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 422
 423         tid_tx->timeout = timeout;
 424
 425         /* Tx timer */
 426         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 427         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 428         init_timer(&tid_tx->addba_resp_timer);
 429
 430         /* assign a dialog token */
 431         sta->ampdu_mlme.dialog_token_allocator++;
 432         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 433
 434         /*
 435          * Finally, assign it to the start array; the work item will
 436          * collect it and move it to the normal array.
 437          */
 438         sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
 439
 440         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 441
 442         /* this flow continues off the work */
 443  err_unlock_sta:
 444         spin_unlock_bh(&sta->lock);
 445         return ret;
 446 }
 447 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 448
 449 /*
 450  * splice packets from the STA's pending to the local pending,
 451  * requires a call to ieee80211_agg_splice_finish later
 452  */
 453 static void __acquires(agg_queue)
 454 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 455                              struct tid_ampdu_tx *tid_tx, u16 tid)
 456 {
 457         int queue = ieee80211_ac_from_tid(tid);
 458         unsigned long flags;
 459
 460         ieee80211_stop_queue_agg(local, tid);
 461
 462         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 463                           " from the pending queue\n", tid))
 464                 return;
 465
 466         if (!skb_queue_empty(&tid_tx->pending)) {
 467                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 468                 /* copy over remaining packets */
 469                 skb_queue_splice_tail_init(&tid_tx->pending,
 470                                            &local->pending[queue]);
 471                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 472         }
 473 }
 474
 475 static void __releases(agg_queue)
 476 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 477 {
 478         ieee80211_wake_queue_agg(local, tid);
 479 }
 480
 481 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 482                                          struct sta_info *sta, u16 tid)
 483 {
 484         struct tid_ampdu_tx *tid_tx;
 485
 486         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 487
 488         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 489
 490 #ifdef CONFIG_MAC80211_HT_DEBUG
 491         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 492 #endif
 493
 494         drv_ampdu_action(local, sta->sdata,
 495                          IEEE80211_AMPDU_TX_OPERATIONAL,
 496                          &sta->sta, tid, NULL, tid_tx->buf_size);
 497
 498         /*
 499          * synchronize with TX path, while splicing the TX path
 500          * should block so it won't put more packets onto pending.
 501          */
 502         spin_lock_bh(&sta->lock);
 503
 504         ieee80211_agg_splice_packets(local, tid_tx, tid);
 505         /*
 506          * Now mark as operational. This will be visible
 507          * in the TX path, and lets it go lock-free in
 508          * the common case.
 509          */
 510         set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 511         ieee80211_agg_splice_finish(local, tid);
 512
 513         spin_unlock_bh(&sta->lock);
 514 }
 515
 516 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 517 {
 518         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 519         struct ieee80211_local *local = sdata->local;
 520         struct sta_info *sta;
 521         struct tid_ampdu_tx *tid_tx;
 522
 523         trace_api_start_tx_ba_cb(sdata, ra, tid);
 524
 525         if (tid >= STA_TID_NUM) {
 526 #ifdef CONFIG_MAC80211_HT_DEBUG
 527                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 528                                 tid, STA_TID_NUM);
 529 #endif
 530                 return;
 531         }
 532
 533         mutex_lock(&local->sta_mtx);
 534         sta = sta_info_get(sdata, ra);
 535         if (!sta) {
 536                 mutex_unlock(&local->sta_mtx);
 537 #ifdef CONFIG_MAC80211_HT_DEBUG
 538                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 539 #endif
 540                 return;
 541         }
 542
 543         mutex_lock(&sta->ampdu_mlme.mtx);
 544         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 545
 546         if (WARN_ON(!tid_tx)) {
 547 #ifdef CONFIG_MAC80211_HT_DEBUG
 548                 printk(KERN_DEBUG "addBA was not requested!\n");
 549 #endif
 550                 goto unlock;
 551         }
 552
 553         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 554                 goto unlock;
 555
 556         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 557                 ieee80211_agg_tx_operational(local, sta, tid);
 558
 559  unlock:
 560         mutex_unlock(&sta->ampdu_mlme.mtx);
 561         mutex_unlock(&local->sta_mtx);
 562 }
 563
 564 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 565                                       const u8 *ra, u16 tid)
 566 {
 567         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 568         struct ieee80211_local *local = sdata->local;
 569         struct ieee80211_ra_tid *ra_tid;
 570         struct sk_buff *skb = dev_alloc_skb(0);
 571
 572         if (unlikely(!skb))
 573                 return;
 574
 575         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 576         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 577         ra_tid->tid = tid;
 578
 579         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 580         skb_queue_tail(&sdata->skb_queue, skb);
 581         ieee80211_queue_work(&local->hw, &sdata->work);
 582 }
 583 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 584
 585 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 586                                    enum ieee80211_back_parties initiator,
 587                                    bool tx)
 588 {
 589         int ret;
 590
 591         mutex_lock(&sta->ampdu_mlme.mtx);
 592
 593         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator, tx);
 594
 595         mutex_unlock(&sta->ampdu_mlme.mtx);
 596
 597         return ret;
 598 }
 599
 600 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 601 {
 602         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 603         struct ieee80211_sub_if_data *sdata = sta->sdata;
 604         struct ieee80211_local *local = sdata->local;
 605         struct tid_ampdu_tx *tid_tx;
 606         int ret = 0;
 607
 608         trace_api_stop_tx_ba_session(pubsta, tid);
 609
 610         if (!local->ops->ampdu_action)
 611                 return -EINVAL;
 612
 613         if (tid >= STA_TID_NUM)
 614                 return -EINVAL;
 615
 616         spin_lock_bh(&sta->lock);
 617         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 618
 619         if (!tid_tx) {
 620                 ret = -ENOENT;
 621                 goto unlock;
 622         }
 623
 624         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 625                 /* already in progress stopping it */
 626                 ret = 0;
 627                 goto unlock;
 628         }
 629
 630         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 631         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 632
 633  unlock:
 634         spin_unlock_bh(&sta->lock);
 635         return ret;
 636 }
 637 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 638
 639 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 640 {
 641         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 642         struct ieee80211_local *local = sdata->local;
 643         struct sta_info *sta;
 644         struct tid_ampdu_tx *tid_tx;
 645
 646         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 647
 648         if (tid >= STA_TID_NUM) {
 649 #ifdef CONFIG_MAC80211_HT_DEBUG
 650                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 651                                 tid, STA_TID_NUM);
 652 #endif
 653                 return;
 654         }
 655
 656 #ifdef CONFIG_MAC80211_HT_DEBUG
 657         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 658                ra, tid);
 659 #endif /* CONFIG_MAC80211_HT_DEBUG */
 660
 661         mutex_lock(&local->sta_mtx);
 662
 663         sta = sta_info_get(sdata, ra);
 664         if (!sta) {
 665 #ifdef CONFIG_MAC80211_HT_DEBUG
 666                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 667 #endif
 668                 goto unlock;
 669         }
 670
 671         mutex_lock(&sta->ampdu_mlme.mtx);
 672         spin_lock_bh(&sta->lock);
 673         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 674
 675         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 676 #ifdef CONFIG_MAC80211_HT_DEBUG
 677                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 678 #endif
 679                 goto unlock_sta;
 680         }
 681
 682         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 683                 ieee80211_send_delba(sta->sdata, ra, tid,
 684                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 685
 686         /*
 687          * When we get here, the TX path will not be lockless any more wrt.
 688          * aggregation, since the OPERATIONAL bit has long been cleared.
 689          * Thus it will block on getting the lock, if it occurs. So if we
 690          * stop the queue now, we will not get any more packets, and any
 691          * that might be being processed will wait for us here, thereby
 692          * guaranteeing that no packets go to the tid_tx pending queue any
 693          * more.
 694          */
 695
 696         ieee80211_agg_splice_packets(local, tid_tx, tid);
 697
 698         /* future packets must not find the tid_tx struct any more */
 699         ieee80211_assign_tid_tx(sta, tid, NULL);
 700
 701         ieee80211_agg_splice_finish(local, tid);
 702
 703         kfree_rcu(tid_tx, rcu_head);
 704
 705  unlock_sta:
 706         spin_unlock_bh(&sta->lock);
 707         mutex_unlock(&sta->ampdu_mlme.mtx);
 708  unlock:
 709         mutex_unlock(&local->sta_mtx);
 710 }
 711
 712 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 713                                      const u8 *ra, u16 tid)
 714 {
 715         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 716         struct ieee80211_local *local = sdata->local;
 717         struct ieee80211_ra_tid *ra_tid;
 718         struct sk_buff *skb = dev_alloc_skb(0);
 719
 720         if (unlikely(!skb))
 721                 return;
 722
 723         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 724         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 725         ra_tid->tid = tid;
 726
 727         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 728         skb_queue_tail(&sdata->skb_queue, skb);
 729         ieee80211_queue_work(&local->hw, &sdata->work);
 730 }
 731 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 732
 733
 734 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 735                                   struct sta_info *sta,
 736                                   struct ieee80211_mgmt *mgmt,
 737                                   size_t len)
 738 {
 739         struct tid_ampdu_tx *tid_tx;
 740         u16 capab, tid;
 741         u8 buf_size;
 742
 743         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 744         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 745         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 746
 747         mutex_lock(&sta->ampdu_mlme.mtx);
 748
 749         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 750         if (!tid_tx)
 751                 goto out;
 752
 753         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 754 #ifdef CONFIG_MAC80211_HT_DEBUG
 755                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 756 #endif
 757                 goto out;
 758         }
 759
 760         del_timer(&tid_tx->addba_resp_timer);
 761
 762 #ifdef CONFIG_MAC80211_HT_DEBUG
 763         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 764 #endif
 765         /*
 766          * IEEE 802.11-2007 7.3.1.14:
 767          * In an ADDBA Response frame, when the Status Code field
 768          * is set to 0, the Buffer Size subfield is set to a value
 769          * of at least 1.
 770          */
 771         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 772                         == WLAN_STATUS_SUCCESS && buf_size) {
 773                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 774                                      &tid_tx->state)) {
 775                         /* ignore duplicate response */
 776                         goto out;
 777                 }
 778
 779                 tid_tx->buf_size = buf_size;
 780
 781                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 782                         ieee80211_agg_tx_operational(local, sta, tid);
 783
 784                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 785         } else {
 786                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
 787                                                 true);
 788         }
 789
 790  out:
 791         mutex_unlock(&sta->ampdu_mlme.mtx);
 792 }