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, 0);
 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, 0);
 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                                      local->hw.max_tx_aggregation_subframes,
 346                                      tid_tx->timeout);
 347 }
 348
 349 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 350                                   u16 timeout)
 351 {
 352         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 353         struct ieee80211_sub_if_data *sdata = sta->sdata;
 354         struct ieee80211_local *local = sdata->local;
 355         struct tid_ampdu_tx *tid_tx;
 356         int ret = 0;
 357
 358         trace_api_start_tx_ba_session(pubsta, tid);
 359
 360         if (WARN_ON(!local->ops->ampdu_action))
 361                 return -EINVAL;
 362
 363         if ((tid >= STA_TID_NUM) ||
 364             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION))
 365                 return -EINVAL;
 366
 367 #ifdef CONFIG_MAC80211_HT_DEBUG
 368         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 369                pubsta->addr, tid);
 370 #endif /* CONFIG_MAC80211_HT_DEBUG */
 371
 372         /*
 373          * The aggregation code is not prepared to handle
 374          * anything but STA/AP due to the BSSID handling.
 375          * IBSS could work in the code but isn't supported
 376          * by drivers or the standard.
 377          */
 378         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 379             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 380             sdata->vif.type != NL80211_IFTYPE_AP)
 381                 return -EINVAL;
 382
 383         if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
 384 #ifdef CONFIG_MAC80211_HT_DEBUG
 385                 printk(KERN_DEBUG "BA sessions blocked. "
 386                        "Denying BA session request\n");
 387 #endif
 388                 return -EINVAL;
 389         }
 390
 391         spin_lock_bh(&sta->lock);
 392
 393         /* we have tried too many times, receiver does not want A-MPDU */
 394         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 395                 ret = -EBUSY;
 396                 goto err_unlock_sta;
 397         }
 398
 399         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 400         /* check if the TID is not in aggregation flow already */
 401         if (tid_tx) {
 402 #ifdef CONFIG_MAC80211_HT_DEBUG
 403                 printk(KERN_DEBUG "BA request denied - session is not "
 404                                  "idle on tid %u\n", tid);
 405 #endif /* CONFIG_MAC80211_HT_DEBUG */
 406                 ret = -EAGAIN;
 407                 goto err_unlock_sta;
 408         }
 409
 410         /* prepare A-MPDU MLME for Tx aggregation */
 411         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 412         if (!tid_tx) {
 413 #ifdef CONFIG_MAC80211_HT_DEBUG
 414                 if (net_ratelimit())
 415                         printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
 416                                         tid);
 417 #endif
 418                 ret = -ENOMEM;
 419                 goto err_unlock_sta;
 420         }
 421
 422         skb_queue_head_init(&tid_tx->pending);
 423         __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 424
 425         tid_tx->timeout = timeout;
 426
 427         /* Tx timer */
 428         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 429         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 430         init_timer(&tid_tx->addba_resp_timer);
 431
 432         /* assign a dialog token */
 433         sta->ampdu_mlme.dialog_token_allocator++;
 434         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 435
 436         /* finally, assign it to the array */
 437         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 438
 439         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 440
 441         /* this flow continues off the work */
 442  err_unlock_sta:
 443         spin_unlock_bh(&sta->lock);
 444         return ret;
 445 }
 446 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 447
 448 /*
 449  * splice packets from the STA's pending to the local pending,
 450  * requires a call to ieee80211_agg_splice_finish later
 451  */
 452 static void __acquires(agg_queue)
 453 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 454                              struct tid_ampdu_tx *tid_tx, u16 tid)
 455 {
 456         int queue = ieee80211_ac_from_tid(tid);
 457         unsigned long flags;
 458
 459         ieee80211_stop_queue_agg(local, tid);
 460
 461         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 462                           " from the pending queue\n", tid))
 463                 return;
 464
 465         if (!skb_queue_empty(&tid_tx->pending)) {
 466                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 467                 /* copy over remaining packets */
 468                 skb_queue_splice_tail_init(&tid_tx->pending,
 469                                            &local->pending[queue]);
 470                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 471         }
 472 }
 473
 474 static void __releases(agg_queue)
 475 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 476 {
 477         ieee80211_wake_queue_agg(local, tid);
 478 }
 479
 480 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 481                                          struct sta_info *sta, u16 tid)
 482 {
 483         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 484
 485 #ifdef CONFIG_MAC80211_HT_DEBUG
 486         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 487 #endif
 488
 489         drv_ampdu_action(local, sta->sdata,
 490                          IEEE80211_AMPDU_TX_OPERATIONAL,
 491                          &sta->sta, tid, NULL,
 492                          sta->ampdu_mlme.tid_tx[tid]->buf_size);
 493
 494         /*
 495          * synchronize with TX path, while splicing the TX path
 496          * should block so it won't put more packets onto pending.
 497          */
 498         spin_lock_bh(&sta->lock);
 499
 500         ieee80211_agg_splice_packets(local, sta->ampdu_mlme.tid_tx[tid], tid);
 501         /*
 502          * Now mark as operational. This will be visible
 503          * in the TX path, and lets it go lock-free in
 504          * the common case.
 505          */
 506         set_bit(HT_AGG_STATE_OPERATIONAL, &sta->ampdu_mlme.tid_tx[tid]->state);
 507         ieee80211_agg_splice_finish(local, tid);
 508
 509         spin_unlock_bh(&sta->lock);
 510 }
 511
 512 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 513 {
 514         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 515         struct ieee80211_local *local = sdata->local;
 516         struct sta_info *sta;
 517         struct tid_ampdu_tx *tid_tx;
 518
 519         trace_api_start_tx_ba_cb(sdata, ra, tid);
 520
 521         if (tid >= STA_TID_NUM) {
 522 #ifdef CONFIG_MAC80211_HT_DEBUG
 523                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 524                                 tid, STA_TID_NUM);
 525 #endif
 526                 return;
 527         }
 528
 529         mutex_lock(&local->sta_mtx);
 530         sta = sta_info_get(sdata, ra);
 531         if (!sta) {
 532                 mutex_unlock(&local->sta_mtx);
 533 #ifdef CONFIG_MAC80211_HT_DEBUG
 534                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 535 #endif
 536                 return;
 537         }
 538
 539         mutex_lock(&sta->ampdu_mlme.mtx);
 540         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 541
 542         if (WARN_ON(!tid_tx)) {
 543 #ifdef CONFIG_MAC80211_HT_DEBUG
 544                 printk(KERN_DEBUG "addBA was not requested!\n");
 545 #endif
 546                 goto unlock;
 547         }
 548
 549         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 550                 goto unlock;
 551
 552         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 553                 ieee80211_agg_tx_operational(local, sta, tid);
 554
 555  unlock:
 556         mutex_unlock(&sta->ampdu_mlme.mtx);
 557         mutex_unlock(&local->sta_mtx);
 558 }
 559
 560 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 561                                       const u8 *ra, u16 tid)
 562 {
 563         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 564         struct ieee80211_local *local = sdata->local;
 565         struct ieee80211_ra_tid *ra_tid;
 566         struct sk_buff *skb = dev_alloc_skb(0);
 567
 568         if (unlikely(!skb)) {
 569 #ifdef CONFIG_MAC80211_HT_DEBUG
 570                 if (net_ratelimit())
 571                         printk(KERN_WARNING "%s: Not enough memory, "
 572                                "dropping start BA session", sdata->name);
 573 #endif
 574                 return;
 575         }
 576         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 577         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 578         ra_tid->tid = tid;
 579
 580         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 581         skb_queue_tail(&sdata->skb_queue, skb);
 582         ieee80211_queue_work(&local->hw, &sdata->work);
 583 }
 584 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 585
 586 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 587                                    enum ieee80211_back_parties initiator,
 588                                    bool tx)
 589 {
 590         int ret;
 591
 592         mutex_lock(&sta->ampdu_mlme.mtx);
 593
 594         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator, tx);
 595
 596         mutex_unlock(&sta->ampdu_mlme.mtx);
 597
 598         return ret;
 599 }
 600
 601 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 602 {
 603         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 604         struct ieee80211_sub_if_data *sdata = sta->sdata;
 605         struct ieee80211_local *local = sdata->local;
 606         struct tid_ampdu_tx *tid_tx;
 607         int ret = 0;
 608
 609         trace_api_stop_tx_ba_session(pubsta, tid);
 610
 611         if (!local->ops->ampdu_action)
 612                 return -EINVAL;
 613
 614         if (tid >= STA_TID_NUM)
 615                 return -EINVAL;
 616
 617         spin_lock_bh(&sta->lock);
 618         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 619
 620         if (!tid_tx) {
 621                 ret = -ENOENT;
 622                 goto unlock;
 623         }
 624
 625         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 626                 /* already in progress stopping it */
 627                 ret = 0;
 628                 goto unlock;
 629         }
 630
 631         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 632         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 633
 634  unlock:
 635         spin_unlock_bh(&sta->lock);
 636         return ret;
 637 }
 638 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 639
 640 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 641 {
 642         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 643         struct ieee80211_local *local = sdata->local;
 644         struct sta_info *sta;
 645         struct tid_ampdu_tx *tid_tx;
 646
 647         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 648
 649         if (tid >= STA_TID_NUM) {
 650 #ifdef CONFIG_MAC80211_HT_DEBUG
 651                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 652                                 tid, STA_TID_NUM);
 653 #endif
 654                 return;
 655         }
 656
 657 #ifdef CONFIG_MAC80211_HT_DEBUG
 658         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 659                ra, tid);
 660 #endif /* CONFIG_MAC80211_HT_DEBUG */
 661
 662         mutex_lock(&local->sta_mtx);
 663
 664         sta = sta_info_get(sdata, ra);
 665         if (!sta) {
 666 #ifdef CONFIG_MAC80211_HT_DEBUG
 667                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 668 #endif
 669                 goto unlock;
 670         }
 671
 672         mutex_lock(&sta->ampdu_mlme.mtx);
 673         spin_lock_bh(&sta->lock);
 674         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 675
 676         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 677 #ifdef CONFIG_MAC80211_HT_DEBUG
 678                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 679 #endif
 680                 goto unlock_sta;
 681         }
 682
 683         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 684                 ieee80211_send_delba(sta->sdata, ra, tid,
 685                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 686
 687         /*
 688          * When we get here, the TX path will not be lockless any more wrt.
 689          * aggregation, since the OPERATIONAL bit has long been cleared.
 690          * Thus it will block on getting the lock, if it occurs. So if we
 691          * stop the queue now, we will not get any more packets, and any
 692          * that might be being processed will wait for us here, thereby
 693          * guaranteeing that no packets go to the tid_tx pending queue any
 694          * more.
 695          */
 696
 697         ieee80211_agg_splice_packets(local, tid_tx, tid);
 698
 699         /* future packets must not find the tid_tx struct any more */
 700         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
 701
 702         ieee80211_agg_splice_finish(local, tid);
 703
 704         call_rcu(&tid_tx->rcu_head, kfree_tid_tx);
 705
 706  unlock_sta:
 707         spin_unlock_bh(&sta->lock);
 708         mutex_unlock(&sta->ampdu_mlme.mtx);
 709  unlock:
 710         mutex_unlock(&local->sta_mtx);
 711 }
 712
 713 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 714                                      const u8 *ra, u16 tid)
 715 {
 716         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 717         struct ieee80211_local *local = sdata->local;
 718         struct ieee80211_ra_tid *ra_tid;
 719         struct sk_buff *skb = dev_alloc_skb(0);
 720
 721         if (unlikely(!skb)) {
 722 #ifdef CONFIG_MAC80211_HT_DEBUG
 723                 if (net_ratelimit())
 724                         printk(KERN_WARNING "%s: Not enough memory, "
 725                                "dropping stop BA session", sdata->name);
 726 #endif
 727                 return;
 728         }
 729         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 730         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 731         ra_tid->tid = tid;
 732
 733         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 734         skb_queue_tail(&sdata->skb_queue, skb);
 735         ieee80211_queue_work(&local->hw, &sdata->work);
 736 }
 737 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 738
 739
 740 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 741                                   struct sta_info *sta,
 742                                   struct ieee80211_mgmt *mgmt,
 743                                   size_t len)
 744 {
 745         struct tid_ampdu_tx *tid_tx;
 746         u16 capab, tid;
 747         u8 buf_size;
 748
 749         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 750         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 751         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 752
 753         mutex_lock(&sta->ampdu_mlme.mtx);
 754
 755         tid_tx = sta->ampdu_mlme.tid_tx[tid];
 756         if (!tid_tx)
 757                 goto out;
 758
 759         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 760 #ifdef CONFIG_MAC80211_HT_DEBUG
 761                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 762 #endif
 763                 goto out;
 764         }
 765
 766         del_timer(&tid_tx->addba_resp_timer);
 767
 768 #ifdef CONFIG_MAC80211_HT_DEBUG
 769         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 770 #endif
 771
 772         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 773                         == WLAN_STATUS_SUCCESS) {
 774                 /*
 775                  * IEEE 802.11-2007 7.3.1.14:
 776                  * In an ADDBA Response frame, when the Status Code field
 777                  * is set to 0, the Buffer Size subfield is set to a value
 778                  * of at least 1.
 779                  */
 780                 if (!buf_size)
 781                         goto out;
 782
 783                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 784                                      &tid_tx->state)) {
 785                         /* ignore duplicate response */
 786                         goto out;
 787                 }
 788
 789                 tid_tx->buf_size = buf_size;
 790
 791                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 792                         ieee80211_agg_tx_operational(local, sta, tid);
 793
 794                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 795         } else {
 796                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
 797                                                 true);
 798         }
 799
 800  out:
 801         mutex_unlock(&sta->ampdu_mlme.mtx);
 802 }