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                                     bool tx)
 150 {
 151         struct ieee80211_local *local = sta->local;
 152         struct tid_ampdu_tx *tid_tx = sta->ampdu_mlme.tid_tx[tid];
 153         int ret;
 154
 155         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 156
 157         if (!tid_tx)
 158                 return -ENOENT;
 159
 160         spin_lock_bh(&sta->lock);
 161
 162         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 163                 /* not even started yet! */
 164                 rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
 165                 spin_unlock_bh(&sta->lock);
 166                 call_rcu(&tid_tx->rcu_head, kfree_tid_tx);
 167                 return 0;
 168         }
 169
 170         spin_unlock_bh(&sta->lock);
 171
 172 #ifdef CONFIG_MAC80211_HT_DEBUG
 173         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 174                sta->sta.addr, tid);
 175 #endif /* CONFIG_MAC80211_HT_DEBUG */
 176
 177         set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 178
 179         del_timer_sync(&tid_tx->addba_resp_timer);
 180
 181         /*
 182          * After this packets are no longer handed right through
 183          * to the driver but are put onto tid_tx->pending instead,
 184          * with locking to ensure proper access.
 185          */
 186         clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 187
 188         tid_tx->stop_initiator = initiator;
 189         tid_tx->tx_stop = tx;
 190
 191         ret = drv_ampdu_action(local, sta->sdata,
 192                                IEEE80211_AMPDU_TX_STOP,
 193                                &sta->sta, tid, NULL);
 194
 195         /* HW shall not deny going back to legacy */
 196         if (WARN_ON(ret)) {
 197                 /*
 198                  * We may have pending packets get stuck in this case...
 199                  * Not bothering with a workaround for now.
 200                  */
 201         }
 202
 203         return ret;
 204 }
 205
 206 /*
 207  * After sending add Block Ack request we activated a timer until
 208  * add Block Ack response will arrive from the recipient.
 209  * If this timer expires sta_addba_resp_timer_expired will be executed.
 210  */
 211 static void sta_addba_resp_timer_expired(unsigned long data)
 212 {
 213         /* not an elegant detour, but there is no choice as the timer passes
 214          * only one argument, and both sta_info and TID are needed, so init
 215          * flow in sta_info_create gives the TID as data, while the timer_to_id
 216          * array gives the sta through container_of */
 217         u16 tid = *(u8 *)data;
 218         struct sta_info *sta = container_of((void *)data,
 219                 struct sta_info, timer_to_tid[tid]);
 220         struct tid_ampdu_tx *tid_tx;
 221
 222         /* check if the TID waits for addBA response */
 223         rcu_read_lock();
 224         tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 225         if (!tid_tx ||
 226             test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 227                 rcu_read_unlock();
 228 #ifdef CONFIG_MAC80211_HT_DEBUG
 229                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 230                                 "(or no longer) expecting addBA response there\n",
 231                         tid);
 232 #endif
 233                 return;
 234         }
 235
 236 #ifdef CONFIG_MAC80211_HT_DEBUG
 237         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 238 #endif
 239
 240         ieee80211_stop_tx_ba_session(&sta->sta, tid);
 241         rcu_read_unlock();
 242 }
 243
 244 static inline int ieee80211_ac_from_tid(int tid)
 245 {
 246         return ieee802_1d_to_ac[tid & 7];
 247 }
 248
 249 /*
 250  * When multiple aggregation sessions on multiple stations
 251  * are being created/destroyed simultaneously, we need to
 252  * refcount the global queue stop caused by that in order
 253  * to not get into a situation where one of the aggregation
 254  * setup or teardown re-enables queues before the other is
 255  * ready to handle that.
 256  *
 257  * These two functions take care of this issue by keeping
 258  * a global "agg_queue_stop" refcount.
 259  */
 260 static void __acquires(agg_queue)
 261 ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
 262 {
 263         int queue = ieee80211_ac_from_tid(tid);
 264
 265         if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
 266                 ieee80211_stop_queue_by_reason(
 267                         &local->hw, queue,
 268                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 269         __acquire(agg_queue);
 270 }
 271
 272 static void __releases(agg_queue)
 273 ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 274 {
 275         int queue = ieee80211_ac_from_tid(tid);
 276
 277         if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
 278                 ieee80211_wake_queue_by_reason(
 279                         &local->hw, queue,
 280                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 281         __release(agg_queue);
 282 }
 283
 284 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 285 {
 286         struct tid_ampdu_tx *tid_tx = sta->ampdu_mlme.tid_tx[tid];
 287         struct ieee80211_local *local = sta->local;
 288         struct ieee80211_sub_if_data *sdata = sta->sdata;
 289         u16 start_seq_num;
 290         int ret;
 291
 292         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 293
 294         /*
 295          * While we're asking the driver about the aggregation,
 296          * stop the AC queue so that we don't have to worry
 297          * about frames that came in while we were doing that,
 298          * which would require us to put them to the AC pending
 299          * afterwards which just makes the code more complex.
 300          */
 301         ieee80211_stop_queue_agg(local, tid);
 302
 303         clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 304
 305         /*
 306          * make sure no packets are being processed to get
 307          * valid starting sequence number
 308          */
 309         synchronize_net();
 310
 311         start_seq_num = sta->tid_seq[tid] >> 4;
 312
 313         ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 314                                &sta->sta, tid, &start_seq_num);
 315         if (ret) {
 316 #ifdef CONFIG_MAC80211_HT_DEBUG
 317                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 318                                         " tid %d\n", tid);
 319 #endif
 320                 spin_lock_bh(&sta->lock);
 321                 rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
 322                 spin_unlock_bh(&sta->lock);
 323
 324                 ieee80211_wake_queue_agg(local, tid);
 325                 call_rcu(&tid_tx->rcu_head, kfree_tid_tx);
 326                 return;
 327         }
 328
 329         /* we can take packets again now */
 330         ieee80211_wake_queue_agg(local, tid);
 331
 332         /* activate the timer for the recipient's addBA response */
 333         mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 334 #ifdef CONFIG_MAC80211_HT_DEBUG
 335         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 336 #endif
 337
 338         spin_lock_bh(&sta->lock);
 339         sta->ampdu_mlme.addba_req_num[tid]++;
 340         spin_unlock_bh(&sta->lock);
 341
 342         /* send AddBA request */
 343         ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 344                                      tid_tx->dialog_token, start_seq_num,
 345                                      0x40, 5000);
 346 }
 347
 348 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 349 {
 350         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 351         struct ieee80211_sub_if_data *sdata = sta->sdata;
 352         struct ieee80211_local *local = sdata->local;
 353         struct tid_ampdu_tx *tid_tx;
 354         int ret = 0;
 355
 356         trace_api_start_tx_ba_session(pubsta, tid);
 357
 358         if (WARN_ON(!local->ops->ampdu_action))
 359                 return -EINVAL;
 360
 361         if ((tid >= STA_TID_NUM) ||
 362             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION))
 363                 return -EINVAL;
 364
 365 #ifdef CONFIG_MAC80211_HT_DEBUG
 366         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 367                pubsta->addr, tid);
 368 #endif /* CONFIG_MAC80211_HT_DEBUG */
 369
 370         /*
 371          * The aggregation code is not prepared to handle
 372          * anything but STA/AP due to the BSSID handling.
 373          * IBSS could work in the code but isn't supported
 374          * by drivers or the standard.
 375          */
 376         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 377             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 378             sdata->vif.type != NL80211_IFTYPE_AP)
 379                 return -EINVAL;
 380
 381         if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
 382 #ifdef CONFIG_MAC80211_HT_DEBUG
 383                 printk(KERN_DEBUG "BA sessions blocked. "
 384                        "Denying BA session request\n");
 385 #endif
 386                 return -EINVAL;
 387         }
 388
 389         spin_lock_bh(&sta->lock);
 390
 391         /* we have tried too many times, receiver does not want A-MPDU */
 392         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 393                 ret = -EBUSY;
 394                 goto err_unlock_sta;
 395         }
 396
 397         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 398         /* check if the TID is not in aggregation flow already */
 399         if (tid_tx) {
 400 #ifdef CONFIG_MAC80211_HT_DEBUG
 401                 printk(KERN_DEBUG "BA request denied - session is not "
 402                                  "idle on tid %u\n", tid);
 403 #endif /* CONFIG_MAC80211_HT_DEBUG */
 404                 ret = -EAGAIN;
 405                 goto err_unlock_sta;
 406         }
 407
 408         /* prepare A-MPDU MLME for Tx aggregation */
 409         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 410         if (!tid_tx) {
 411 #ifdef CONFIG_MAC80211_HT_DEBUG
 412                 if (net_ratelimit())
 413                         printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
 414                                         tid);
 415 #endif
 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         /* Tx timer */
 424         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 425         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 426         init_timer(&tid_tx->addba_resp_timer);
 427
 428         /* assign a dialog token */
 429         sta->ampdu_mlme.dialog_token_allocator++;
 430         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 431
 432         /* finally, assign it to the array */
 433         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 434
 435         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 436
 437         /* this flow continues off the work */
 438  err_unlock_sta:
 439         spin_unlock_bh(&sta->lock);
 440         return ret;
 441 }
 442 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 443
 444 /*
 445  * splice packets from the STA's pending to the local pending,
 446  * requires a call to ieee80211_agg_splice_finish later
 447  */
 448 static void __acquires(agg_queue)
 449 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 450                              struct tid_ampdu_tx *tid_tx, u16 tid)
 451 {
 452         int queue = ieee80211_ac_from_tid(tid);
 453         unsigned long flags;
 454
 455         ieee80211_stop_queue_agg(local, tid);
 456
 457         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 458                           " from the pending queue\n", tid))
 459                 return;
 460
 461         if (!skb_queue_empty(&tid_tx->pending)) {
 462                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 463                 /* copy over remaining packets */
 464                 skb_queue_splice_tail_init(&tid_tx->pending,
 465                                            &local->pending[queue]);
 466                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 467         }
 468 }
 469
 470 static void __releases(agg_queue)
 471 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 472 {
 473         ieee80211_wake_queue_agg(local, tid);
 474 }
 475
 476 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 477                                          struct sta_info *sta, u16 tid)
 478 {
 479         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 480
 481 #ifdef CONFIG_MAC80211_HT_DEBUG
 482         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 483 #endif
 484
 485         drv_ampdu_action(local, sta->sdata,
 486                          IEEE80211_AMPDU_TX_OPERATIONAL,
 487                          &sta->sta, tid, NULL);
 488
 489         /*
 490          * synchronize with TX path, while splicing the TX path
 491          * should block so it won't put more packets onto pending.
 492          */
 493         spin_lock_bh(&sta->lock);
 494
 495         ieee80211_agg_splice_packets(local, sta->ampdu_mlme.tid_tx[tid], tid);
 496         /*
 497          * Now mark as operational. This will be visible
 498          * in the TX path, and lets it go lock-free in
 499          * the common case.
 500          */
 501         set_bit(HT_AGG_STATE_OPERATIONAL, &sta->ampdu_mlme.tid_tx[tid]->state);
 502         ieee80211_agg_splice_finish(local, tid);
 503
 504         spin_unlock_bh(&sta->lock);
 505 }
 506
 507 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 508 {
 509         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 510         struct ieee80211_local *local = sdata->local;
 511         struct sta_info *sta;
 512         struct tid_ampdu_tx *tid_tx;
 513
 514         trace_api_start_tx_ba_cb(sdata, ra, tid);
 515
 516         if (tid >= STA_TID_NUM) {
 517 #ifdef CONFIG_MAC80211_HT_DEBUG
 518                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 519                                 tid, STA_TID_NUM);
 520 #endif
 521                 return;
 522         }
 523
 524         mutex_lock(&local->sta_mtx);
 525         sta = sta_info_get(sdata, ra);
 526         if (!sta) {
 527                 mutex_unlock(&local->sta_mtx);
 528 #ifdef CONFIG_MAC80211_HT_DEBUG
 529                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 530 #endif
 531                 return;
 532         }
 533
 534         mutex_lock(&sta->ampdu_mlme.mtx);
 535         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 536
 537         if (WARN_ON(!tid_tx)) {
 538 #ifdef CONFIG_MAC80211_HT_DEBUG
 539                 printk(KERN_DEBUG "addBA was not requested!\n");
 540 #endif
 541                 goto unlock;
 542         }
 543
 544         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 545                 goto unlock;
 546
 547         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 548                 ieee80211_agg_tx_operational(local, sta, tid);
 549
 550  unlock:
 551         mutex_unlock(&sta->ampdu_mlme.mtx);
 552         mutex_unlock(&local->sta_mtx);
 553 }
 554
 555 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 556                                       const u8 *ra, u16 tid)
 557 {
 558         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 559         struct ieee80211_local *local = sdata->local;
 560         struct ieee80211_ra_tid *ra_tid;
 561         struct sk_buff *skb = dev_alloc_skb(0);
 562
 563         if (unlikely(!skb)) {
 564 #ifdef CONFIG_MAC80211_HT_DEBUG
 565                 if (net_ratelimit())
 566                         printk(KERN_WARNING "%s: Not enough memory, "
 567                                "dropping start BA session", sdata->name);
 568 #endif
 569                 return;
 570         }
 571         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 572         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 573         ra_tid->tid = tid;
 574
 575         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 576         skb_queue_tail(&sdata->skb_queue, skb);
 577         ieee80211_queue_work(&local->hw, &sdata->work);
 578 }
 579 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 580
 581 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 582                                    enum ieee80211_back_parties initiator,
 583                                    bool tx)
 584 {
 585         int ret;
 586
 587         mutex_lock(&sta->ampdu_mlme.mtx);
 588
 589         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator, tx);
 590
 591         mutex_unlock(&sta->ampdu_mlme.mtx);
 592
 593         return ret;
 594 }
 595
 596 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 597 {
 598         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 599         struct ieee80211_sub_if_data *sdata = sta->sdata;
 600         struct ieee80211_local *local = sdata->local;
 601         struct tid_ampdu_tx *tid_tx;
 602         int ret = 0;
 603
 604         trace_api_stop_tx_ba_session(pubsta, tid);
 605
 606         if (!local->ops->ampdu_action)
 607                 return -EINVAL;
 608
 609         if (tid >= STA_TID_NUM)
 610                 return -EINVAL;
 611
 612         spin_lock_bh(&sta->lock);
 613         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 614
 615         if (!tid_tx) {
 616                 ret = -ENOENT;
 617                 goto unlock;
 618         }
 619
 620         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 621                 /* already in progress stopping it */
 622                 ret = 0;
 623                 goto unlock;
 624         }
 625
 626         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 627         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 628
 629  unlock:
 630         spin_unlock_bh(&sta->lock);
 631         return ret;
 632 }
 633 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 634
 635 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 636 {
 637         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 638         struct ieee80211_local *local = sdata->local;
 639         struct sta_info *sta;
 640         struct tid_ampdu_tx *tid_tx;
 641
 642         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 643
 644         if (tid >= STA_TID_NUM) {
 645 #ifdef CONFIG_MAC80211_HT_DEBUG
 646                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 647                                 tid, STA_TID_NUM);
 648 #endif
 649                 return;
 650         }
 651
 652 #ifdef CONFIG_MAC80211_HT_DEBUG
 653         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 654                ra, tid);
 655 #endif /* CONFIG_MAC80211_HT_DEBUG */
 656
 657         mutex_lock(&local->sta_mtx);
 658
 659         sta = sta_info_get(sdata, ra);
 660         if (!sta) {
 661 #ifdef CONFIG_MAC80211_HT_DEBUG
 662                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 663 #endif
 664                 goto unlock;
 665         }
 666
 667         mutex_lock(&sta->ampdu_mlme.mtx);
 668         spin_lock_bh(&sta->lock);
 669         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 670
 671         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 672 #ifdef CONFIG_MAC80211_HT_DEBUG
 673                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 674 #endif
 675                 goto unlock_sta;
 676         }
 677
 678         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 679                 ieee80211_send_delba(sta->sdata, ra, tid,
 680                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 681
 682         /*
 683          * When we get here, the TX path will not be lockless any more wrt.
 684          * aggregation, since the OPERATIONAL bit has long been cleared.
 685          * Thus it will block on getting the lock, if it occurs. So if we
 686          * stop the queue now, we will not get any more packets, and any
 687          * that might be being processed will wait for us here, thereby
 688          * guaranteeing that no packets go to the tid_tx pending queue any
 689          * more.
 690          */
 691
 692         ieee80211_agg_splice_packets(local, tid_tx, tid);
 693
 694         /* future packets must not find the tid_tx struct any more */
 695         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
 696
 697         ieee80211_agg_splice_finish(local, tid);
 698
 699         call_rcu(&tid_tx->rcu_head, kfree_tid_tx);
 700
 701  unlock_sta:
 702         spin_unlock_bh(&sta->lock);
 703         mutex_unlock(&sta->ampdu_mlme.mtx);
 704  unlock:
 705         mutex_unlock(&local->sta_mtx);
 706 }
 707
 708 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 709                                      const u8 *ra, u16 tid)
 710 {
 711         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 712         struct ieee80211_local *local = sdata->local;
 713         struct ieee80211_ra_tid *ra_tid;
 714         struct sk_buff *skb = dev_alloc_skb(0);
 715
 716         if (unlikely(!skb)) {
 717 #ifdef CONFIG_MAC80211_HT_DEBUG
 718                 if (net_ratelimit())
 719                         printk(KERN_WARNING "%s: Not enough memory, "
 720                                "dropping stop BA session", sdata->name);
 721 #endif
 722                 return;
 723         }
 724         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 725         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 726         ra_tid->tid = tid;
 727
 728         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 729         skb_queue_tail(&sdata->skb_queue, skb);
 730         ieee80211_queue_work(&local->hw, &sdata->work);
 731 }
 732 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 733
 734
 735 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 736                                   struct sta_info *sta,
 737                                   struct ieee80211_mgmt *mgmt,
 738                                   size_t len)
 739 {
 740         struct tid_ampdu_tx *tid_tx;
 741         u16 capab, tid;
 742
 743         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 744         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 745
 746         mutex_lock(&sta->ampdu_mlme.mtx);
 747
 748         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 749         if (!tid_tx)
 750                 goto out;
 751
 752         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 753 #ifdef CONFIG_MAC80211_HT_DEBUG
 754                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 755 #endif
 756                 goto out;
 757         }
 758
 759         del_timer(&tid_tx->addba_resp_timer);
 760
 761 #ifdef CONFIG_MAC80211_HT_DEBUG
 762         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 763 #endif
 764
 765         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 766                         == WLAN_STATUS_SUCCESS) {
 767                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 768                                      &tid_tx->state)) {
 769                         /* ignore duplicate response */
 770                         goto out;
 771                 }
 772
 773                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 774                         ieee80211_agg_tx_operational(local, sta, tid);
 775
 776                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 777         } else {
 778                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
 779                                                 true);
 780         }
 781
 782  out:
 783         mutex_unlock(&sta->ampdu_mlme.mtx);
 784 }