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 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
 140                              struct tid_ampdu_tx *tid_tx)
 141 {
 142         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 143         lockdep_assert_held(&sta->lock);
 144         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], 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;
 153         int ret;
 154
 155         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 156
 157         spin_lock_bh(&sta->lock);
 158
 159         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 160         if (!tid_tx) {
 161                 spin_unlock_bh(&sta->lock);
 162                 return -ENOENT;
 163         }
 164
 165         /* if we're already stopping ignore any new requests to stop */
 166         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 167                 spin_unlock_bh(&sta->lock);
 168                 return -EALREADY;
 169         }
 170
 171         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 172                 /* not even started yet! */
 173                 ieee80211_assign_tid_tx(sta, tid, NULL);
 174                 spin_unlock_bh(&sta->lock);
 175                 kfree_rcu(tid_tx, rcu_head);
 176                 return 0;
 177         }
 178
 179         set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 180
 181         spin_unlock_bh(&sta->lock);
 182
 183 #ifdef CONFIG_MAC80211_HT_DEBUG
 184         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 185                sta->sta.addr, tid);
 186 #endif /* CONFIG_MAC80211_HT_DEBUG */
 187
 188         del_timer_sync(&tid_tx->addba_resp_timer);
 189
 190         /*
 191          * After this packets are no longer handed right through
 192          * to the driver but are put onto tid_tx->pending instead,
 193          * with locking to ensure proper access.
 194          */
 195         clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 196
 197         /*
 198          * There might be a few packets being processed right now (on
 199          * another CPU) that have already gotten past the aggregation
 200          * check when it was still OPERATIONAL and consequently have
 201          * IEEE80211_TX_CTL_AMPDU set. In that case, this code might
 202          * call into the driver at the same time or even before the
 203          * TX paths calls into it, which could confuse the driver.
 204          *
 205          * Wait for all currently running TX paths to finish before
 206          * telling the driver. New packets will not go through since
 207          * the aggregation session is no longer OPERATIONAL.
 208          */
 209         synchronize_net();
 210
 211         tid_tx->stop_initiator = initiator;
 212         tid_tx->tx_stop = tx;
 213
 214         ret = drv_ampdu_action(local, sta->sdata,
 215                                IEEE80211_AMPDU_TX_STOP,
 216                                &sta->sta, tid, NULL, 0);
 217
 218         /* HW shall not deny going back to legacy */
 219         if (WARN_ON(ret)) {
 220                 /*
 221                  * We may have pending packets get stuck in this case...
 222                  * Not bothering with a workaround for now.
 223                  */
 224         }
 225
 226         return ret;
 227 }
 228
 229 /*
 230  * After sending add Block Ack request we activated a timer until
 231  * add Block Ack response will arrive from the recipient.
 232  * If this timer expires sta_addba_resp_timer_expired will be executed.
 233  */
 234 static void sta_addba_resp_timer_expired(unsigned long data)
 235 {
 236         /* not an elegant detour, but there is no choice as the timer passes
 237          * only one argument, and both sta_info and TID are needed, so init
 238          * flow in sta_info_create gives the TID as data, while the timer_to_id
 239          * array gives the sta through container_of */
 240         u16 tid = *(u8 *)data;
 241         struct sta_info *sta = container_of((void *)data,
 242                 struct sta_info, timer_to_tid[tid]);
 243         struct tid_ampdu_tx *tid_tx;
 244
 245         /* check if the TID waits for addBA response */
 246         rcu_read_lock();
 247         tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 248         if (!tid_tx ||
 249             test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 250                 rcu_read_unlock();
 251 #ifdef CONFIG_MAC80211_HT_DEBUG
 252                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 253                                 "(or no longer) expecting addBA response there\n",
 254                         tid);
 255 #endif
 256                 return;
 257         }
 258
 259 #ifdef CONFIG_MAC80211_HT_DEBUG
 260         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 261 #endif
 262
 263         ieee80211_stop_tx_ba_session(&sta->sta, tid);
 264         rcu_read_unlock();
 265 }
 266
 267 static inline int ieee80211_ac_from_tid(int tid)
 268 {
 269         return ieee802_1d_to_ac[tid & 7];
 270 }
 271
 272 /*
 273  * When multiple aggregation sessions on multiple stations
 274  * are being created/destroyed simultaneously, we need to
 275  * refcount the global queue stop caused by that in order
 276  * to not get into a situation where one of the aggregation
 277  * setup or teardown re-enables queues before the other is
 278  * ready to handle that.
 279  *
 280  * These two functions take care of this issue by keeping
 281  * a global "agg_queue_stop" refcount.
 282  */
 283 static void __acquires(agg_queue)
 284 ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
 285 {
 286         int queue = ieee80211_ac_from_tid(tid);
 287
 288         if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
 289                 ieee80211_stop_queue_by_reason(
 290                         &local->hw, queue,
 291                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 292         __acquire(agg_queue);
 293 }
 294
 295 static void __releases(agg_queue)
 296 ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 297 {
 298         int queue = ieee80211_ac_from_tid(tid);
 299
 300         if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
 301                 ieee80211_wake_queue_by_reason(
 302                         &local->hw, queue,
 303                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 304         __release(agg_queue);
 305 }
 306
 307 /*
 308  * splice packets from the STA's pending to the local pending,
 309  * requires a call to ieee80211_agg_splice_finish later
 310  */
 311 static void __acquires(agg_queue)
 312 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 313                              struct tid_ampdu_tx *tid_tx, u16 tid)
 314 {
 315         int queue = ieee80211_ac_from_tid(tid);
 316         unsigned long flags;
 317
 318         ieee80211_stop_queue_agg(local, tid);
 319
 320         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 321                           " from the pending queue\n", tid))
 322                 return;
 323
 324         if (!skb_queue_empty(&tid_tx->pending)) {
 325                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 326                 /* copy over remaining packets */
 327                 skb_queue_splice_tail_init(&tid_tx->pending,
 328                                            &local->pending[queue]);
 329                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 330         }
 331 }
 332
 333 static void __releases(agg_queue)
 334 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 335 {
 336         ieee80211_wake_queue_agg(local, tid);
 337 }
 338
 339 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 340 {
 341         struct tid_ampdu_tx *tid_tx;
 342         struct ieee80211_local *local = sta->local;
 343         struct ieee80211_sub_if_data *sdata = sta->sdata;
 344         u16 start_seq_num;
 345         int ret;
 346
 347         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 348
 349         /*
 350          * Start queuing up packets for this aggregation session.
 351          * We're going to release them once the driver is OK with
 352          * that.
 353          */
 354         clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 355
 356         /*
 357          * Make sure no packets are being processed. This ensures that
 358          * we have a valid starting sequence number and that in-flight
 359          * packets have been flushed out and no packets for this TID
 360          * will go into the driver during the ampdu_action call.
 361          */
 362         synchronize_net();
 363
 364         start_seq_num = sta->tid_seq[tid] >> 4;
 365
 366         ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 367                                &sta->sta, tid, &start_seq_num, 0);
 368         if (ret) {
 369 #ifdef CONFIG_MAC80211_HT_DEBUG
 370                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 371                                         " tid %d\n", tid);
 372 #endif
 373                 spin_lock_bh(&sta->lock);
 374                 ieee80211_agg_splice_packets(local, tid_tx, tid);
 375                 ieee80211_assign_tid_tx(sta, tid, NULL);
 376                 ieee80211_agg_splice_finish(local, tid);
 377                 spin_unlock_bh(&sta->lock);
 378
 379                 kfree_rcu(tid_tx, rcu_head);
 380                 return;
 381         }
 382
 383         /* activate the timer for the recipient's addBA response */
 384         mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 385 #ifdef CONFIG_MAC80211_HT_DEBUG
 386         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 387 #endif
 388
 389         spin_lock_bh(&sta->lock);
 390         sta->ampdu_mlme.addba_req_num[tid]++;
 391         spin_unlock_bh(&sta->lock);
 392
 393         /* send AddBA request */
 394         ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 395                                      tid_tx->dialog_token, start_seq_num,
 396                                      local->hw.max_tx_aggregation_subframes,
 397                                      tid_tx->timeout);
 398 }
 399
 400 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 401                                   u16 timeout)
 402 {
 403         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 404         struct ieee80211_sub_if_data *sdata = sta->sdata;
 405         struct ieee80211_local *local = sdata->local;
 406         struct tid_ampdu_tx *tid_tx;
 407         int ret = 0;
 408
 409         trace_api_start_tx_ba_session(pubsta, tid);
 410
 411         if (WARN_ON(!local->ops->ampdu_action))
 412                 return -EINVAL;
 413
 414         if ((tid >= STA_TID_NUM) ||
 415             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION))
 416                 return -EINVAL;
 417
 418 #ifdef CONFIG_MAC80211_HT_DEBUG
 419         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 420                pubsta->addr, tid);
 421 #endif /* CONFIG_MAC80211_HT_DEBUG */
 422
 423         /*
 424          * The aggregation code is not prepared to handle
 425          * anything but STA/AP due to the BSSID handling.
 426          * IBSS could work in the code but isn't supported
 427          * by drivers or the standard.
 428          */
 429         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 430             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 431             sdata->vif.type != NL80211_IFTYPE_AP)
 432                 return -EINVAL;
 433
 434         if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
 435 #ifdef CONFIG_MAC80211_HT_DEBUG
 436                 printk(KERN_DEBUG "BA sessions blocked. "
 437                        "Denying BA session request\n");
 438 #endif
 439                 return -EINVAL;
 440         }
 441
 442         spin_lock_bh(&sta->lock);
 443
 444         /* we have tried too many times, receiver does not want A-MPDU */
 445         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 446                 ret = -EBUSY;
 447                 goto err_unlock_sta;
 448         }
 449
 450         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 451         /* check if the TID is not in aggregation flow already */
 452         if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
 453 #ifdef CONFIG_MAC80211_HT_DEBUG
 454                 printk(KERN_DEBUG "BA request denied - session is not "
 455                                  "idle on tid %u\n", tid);
 456 #endif /* CONFIG_MAC80211_HT_DEBUG */
 457                 ret = -EAGAIN;
 458                 goto err_unlock_sta;
 459         }
 460
 461         /* prepare A-MPDU MLME for Tx aggregation */
 462         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 463         if (!tid_tx) {
 464 #ifdef CONFIG_MAC80211_HT_DEBUG
 465                 if (net_ratelimit())
 466                         printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
 467                                         tid);
 468 #endif
 469                 ret = -ENOMEM;
 470                 goto err_unlock_sta;
 471         }
 472
 473         skb_queue_head_init(&tid_tx->pending);
 474         __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 475
 476         tid_tx->timeout = timeout;
 477
 478         /* Tx timer */
 479         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 480         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 481         init_timer(&tid_tx->addba_resp_timer);
 482
 483         /* assign a dialog token */
 484         sta->ampdu_mlme.dialog_token_allocator++;
 485         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 486
 487         /*
 488          * Finally, assign it to the start array; the work item will
 489          * collect it and move it to the normal array.
 490          */
 491         sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
 492
 493         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 494
 495         /* this flow continues off the work */
 496  err_unlock_sta:
 497         spin_unlock_bh(&sta->lock);
 498         return ret;
 499 }
 500 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 501
 502 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 503                                          struct sta_info *sta, u16 tid)
 504 {
 505         struct tid_ampdu_tx *tid_tx;
 506
 507         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 508
 509         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 510
 511 #ifdef CONFIG_MAC80211_HT_DEBUG
 512         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 513 #endif
 514
 515         drv_ampdu_action(local, sta->sdata,
 516                          IEEE80211_AMPDU_TX_OPERATIONAL,
 517                          &sta->sta, tid, NULL, tid_tx->buf_size);
 518
 519         /*
 520          * synchronize with TX path, while splicing the TX path
 521          * should block so it won't put more packets onto pending.
 522          */
 523         spin_lock_bh(&sta->lock);
 524
 525         ieee80211_agg_splice_packets(local, tid_tx, tid);
 526         /*
 527          * Now mark as operational. This will be visible
 528          * in the TX path, and lets it go lock-free in
 529          * the common case.
 530          */
 531         set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 532         ieee80211_agg_splice_finish(local, tid);
 533
 534         spin_unlock_bh(&sta->lock);
 535 }
 536
 537 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 538 {
 539         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 540         struct ieee80211_local *local = sdata->local;
 541         struct sta_info *sta;
 542         struct tid_ampdu_tx *tid_tx;
 543
 544         trace_api_start_tx_ba_cb(sdata, ra, tid);
 545
 546         if (tid >= STA_TID_NUM) {
 547 #ifdef CONFIG_MAC80211_HT_DEBUG
 548                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 549                                 tid, STA_TID_NUM);
 550 #endif
 551                 return;
 552         }
 553
 554         mutex_lock(&local->sta_mtx);
 555         sta = sta_info_get(sdata, ra);
 556         if (!sta) {
 557                 mutex_unlock(&local->sta_mtx);
 558 #ifdef CONFIG_MAC80211_HT_DEBUG
 559                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 560 #endif
 561                 return;
 562         }
 563
 564         mutex_lock(&sta->ampdu_mlme.mtx);
 565         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 566
 567         if (WARN_ON(!tid_tx)) {
 568 #ifdef CONFIG_MAC80211_HT_DEBUG
 569                 printk(KERN_DEBUG "addBA was not requested!\n");
 570 #endif
 571                 goto unlock;
 572         }
 573
 574         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 575                 goto unlock;
 576
 577         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 578                 ieee80211_agg_tx_operational(local, sta, tid);
 579
 580  unlock:
 581         mutex_unlock(&sta->ampdu_mlme.mtx);
 582         mutex_unlock(&local->sta_mtx);
 583 }
 584
 585 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 586                                       const u8 *ra, u16 tid)
 587 {
 588         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 589         struct ieee80211_local *local = sdata->local;
 590         struct ieee80211_ra_tid *ra_tid;
 591         struct sk_buff *skb = dev_alloc_skb(0);
 592
 593         if (unlikely(!skb)) {
 594 #ifdef CONFIG_MAC80211_HT_DEBUG
 595                 if (net_ratelimit())
 596                         printk(KERN_WARNING "%s: Not enough memory, "
 597                                "dropping start BA session", sdata->name);
 598 #endif
 599                 return;
 600         }
 601         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 602         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 603         ra_tid->tid = tid;
 604
 605         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 606         skb_queue_tail(&sdata->skb_queue, skb);
 607         ieee80211_queue_work(&local->hw, &sdata->work);
 608 }
 609 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 610
 611 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 612                                    enum ieee80211_back_parties initiator,
 613                                    bool tx)
 614 {
 615         int ret;
 616
 617         mutex_lock(&sta->ampdu_mlme.mtx);
 618
 619         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator, tx);
 620
 621         mutex_unlock(&sta->ampdu_mlme.mtx);
 622
 623         return ret;
 624 }
 625
 626 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 627 {
 628         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 629         struct ieee80211_sub_if_data *sdata = sta->sdata;
 630         struct ieee80211_local *local = sdata->local;
 631         struct tid_ampdu_tx *tid_tx;
 632         int ret = 0;
 633
 634         trace_api_stop_tx_ba_session(pubsta, tid);
 635
 636         if (!local->ops->ampdu_action)
 637                 return -EINVAL;
 638
 639         if (tid >= STA_TID_NUM)
 640                 return -EINVAL;
 641
 642         spin_lock_bh(&sta->lock);
 643         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 644
 645         if (!tid_tx) {
 646                 ret = -ENOENT;
 647                 goto unlock;
 648         }
 649
 650         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 651                 /* already in progress stopping it */
 652                 ret = 0;
 653                 goto unlock;
 654         }
 655
 656         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 657         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 658
 659  unlock:
 660         spin_unlock_bh(&sta->lock);
 661         return ret;
 662 }
 663 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 664
 665 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 666 {
 667         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 668         struct ieee80211_local *local = sdata->local;
 669         struct sta_info *sta;
 670         struct tid_ampdu_tx *tid_tx;
 671
 672         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 673
 674         if (tid >= STA_TID_NUM) {
 675 #ifdef CONFIG_MAC80211_HT_DEBUG
 676                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 677                                 tid, STA_TID_NUM);
 678 #endif
 679                 return;
 680         }
 681
 682 #ifdef CONFIG_MAC80211_HT_DEBUG
 683         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 684                ra, tid);
 685 #endif /* CONFIG_MAC80211_HT_DEBUG */
 686
 687         mutex_lock(&local->sta_mtx);
 688
 689         sta = sta_info_get(sdata, ra);
 690         if (!sta) {
 691 #ifdef CONFIG_MAC80211_HT_DEBUG
 692                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 693 #endif
 694                 goto unlock;
 695         }
 696
 697         mutex_lock(&sta->ampdu_mlme.mtx);
 698         spin_lock_bh(&sta->lock);
 699         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 700
 701         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 702 #ifdef CONFIG_MAC80211_HT_DEBUG
 703                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 704 #endif
 705                 goto unlock_sta;
 706         }
 707
 708         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 709                 ieee80211_send_delba(sta->sdata, ra, tid,
 710                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 711
 712         /*
 713          * When we get here, the TX path will not be lockless any more wrt.
 714          * aggregation, since the OPERATIONAL bit has long been cleared.
 715          * Thus it will block on getting the lock, if it occurs. So if we
 716          * stop the queue now, we will not get any more packets, and any
 717          * that might be being processed will wait for us here, thereby
 718          * guaranteeing that no packets go to the tid_tx pending queue any
 719          * more.
 720          */
 721
 722         ieee80211_agg_splice_packets(local, tid_tx, tid);
 723
 724         /* future packets must not find the tid_tx struct any more */
 725         ieee80211_assign_tid_tx(sta, tid, NULL);
 726
 727         ieee80211_agg_splice_finish(local, tid);
 728
 729         kfree_rcu(tid_tx, rcu_head);
 730
 731  unlock_sta:
 732         spin_unlock_bh(&sta->lock);
 733         mutex_unlock(&sta->ampdu_mlme.mtx);
 734  unlock:
 735         mutex_unlock(&local->sta_mtx);
 736 }
 737
 738 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 739                                      const u8 *ra, u16 tid)
 740 {
 741         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 742         struct ieee80211_local *local = sdata->local;
 743         struct ieee80211_ra_tid *ra_tid;
 744         struct sk_buff *skb = dev_alloc_skb(0);
 745
 746         if (unlikely(!skb)) {
 747 #ifdef CONFIG_MAC80211_HT_DEBUG
 748                 if (net_ratelimit())
 749                         printk(KERN_WARNING "%s: Not enough memory, "
 750                                "dropping stop BA session", sdata->name);
 751 #endif
 752                 return;
 753         }
 754         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 755         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 756         ra_tid->tid = tid;
 757
 758         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 759         skb_queue_tail(&sdata->skb_queue, skb);
 760         ieee80211_queue_work(&local->hw, &sdata->work);
 761 }
 762 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 763
 764
 765 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 766                                   struct sta_info *sta,
 767                                   struct ieee80211_mgmt *mgmt,
 768                                   size_t len)
 769 {
 770         struct tid_ampdu_tx *tid_tx;
 771         u16 capab, tid;
 772         u8 buf_size;
 773
 774         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 775         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 776         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 777
 778         mutex_lock(&sta->ampdu_mlme.mtx);
 779
 780         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 781         if (!tid_tx)
 782                 goto out;
 783
 784         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 785 #ifdef CONFIG_MAC80211_HT_DEBUG
 786                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 787 #endif
 788                 goto out;
 789         }
 790
 791         del_timer_sync(&tid_tx->addba_resp_timer);
 792
 793 #ifdef CONFIG_MAC80211_HT_DEBUG
 794         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 795 #endif
 796
 797         /*
 798          * addba_resp_timer may have fired before we got here, and
 799          * caused WANT_STOP to be set. If the stop then was already
 800          * processed further, STOPPING might be set.
 801          */
 802         if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
 803             test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 804 #ifdef CONFIG_MAC80211_HT_DEBUG
 805                 printk(KERN_DEBUG
 806                        "got addBA resp for tid %d but we already gave up\n",
 807                        tid);
 808 #endif
 809                 goto out;
 810         }
 811
 812         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 813                         == WLAN_STATUS_SUCCESS) {
 814                 /*
 815                  * IEEE 802.11-2007 7.3.1.14:
 816                  * In an ADDBA Response frame, when the Status Code field
 817                  * is set to 0, the Buffer Size subfield is set to a value
 818                  * of at least 1.
 819                  */
 820                 if (!buf_size)
 821                         goto out;
 822
 823                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 824                                      &tid_tx->state)) {
 825                         /* ignore duplicate response */
 826                         goto out;
 827                 }
 828
 829                 tid_tx->buf_size = buf_size;
 830
 831                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 832                         ieee80211_agg_tx_operational(local, sta, tid);
 833
 834                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 835         } else {
 836                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
 837                                                 true);
 838         }
 839
 840  out:
 841         mutex_unlock(&sta->ampdu_mlme.mtx);
 842 }