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                 return;
  73
  74         skb_reserve(skb, local->hw.extra_tx_headroom);
  75         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
  76         memset(mgmt, 0, 24);
  77         memcpy(mgmt->da, da, ETH_ALEN);
  78         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
  79         if (sdata->vif.type == NL80211_IFTYPE_AP ||
  80             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
  81                 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
  82         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
  83                 memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
  84
  85         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  86                                           IEEE80211_STYPE_ACTION);
  87
  88         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
  89
  90         mgmt->u.action.category = WLAN_CATEGORY_BACK;
  91         mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
  92
  93         mgmt->u.action.u.addba_req.dialog_token = dialog_token;
  94         capab = (u16)(1 << 1);          /* bit 1 aggregation policy */
  95         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
  96         capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
  97
  98         mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
  99
 100         mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
 101         mgmt->u.action.u.addba_req.start_seq_num =
 102                                         cpu_to_le16(start_seq_num << 4);
 103
 104         ieee80211_tx_skb(sdata, skb);
 105 }
 106
 107 void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
 108 {
 109         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 110         struct ieee80211_local *local = sdata->local;
 111         struct sk_buff *skb;
 112         struct ieee80211_bar *bar;
 113         u16 bar_control = 0;
 114
 115         skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
 116         if (!skb)
 117                 return;
 118
 119         skb_reserve(skb, local->hw.extra_tx_headroom);
 120         bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
 121         memset(bar, 0, sizeof(*bar));
 122         bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
 123                                          IEEE80211_STYPE_BACK_REQ);
 124         memcpy(bar->ra, ra, ETH_ALEN);
 125         memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
 126         bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 127         bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
 128         bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
 129         bar->control = cpu_to_le16(bar_control);
 130         bar->start_seq_num = cpu_to_le16(ssn);
 131
 132         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 133         ieee80211_tx_skb(sdata, skb);
 134 }
 135 EXPORT_SYMBOL(ieee80211_send_bar);
 136
 137 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
 138                              struct tid_ampdu_tx *tid_tx)
 139 {
 140         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 141         lockdep_assert_held(&sta->lock);
 142         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 143 }
 144
 145 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 146                                     enum ieee80211_back_parties initiator,
 147                                     bool tx)
 148 {
 149         struct ieee80211_local *local = sta->local;
 150         struct tid_ampdu_tx *tid_tx;
 151         int ret;
 152
 153         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 154
 155         spin_lock_bh(&sta->lock);
 156
 157         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 158         if (!tid_tx) {
 159                 spin_unlock_bh(&sta->lock);
 160                 return -ENOENT;
 161         }
 162
 163         /* if we're already stopping ignore any new requests to stop */
 164         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 165                 spin_unlock_bh(&sta->lock);
 166                 return -EALREADY;
 167         }
 168
 169         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 170                 /* not even started yet! */
 171                 ieee80211_assign_tid_tx(sta, tid, NULL);
 172                 spin_unlock_bh(&sta->lock);
 173                 kfree_rcu(tid_tx, rcu_head);
 174                 return 0;
 175         }
 176
 177         set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 178
 179         spin_unlock_bh(&sta->lock);
 180
 181 #ifdef CONFIG_MAC80211_HT_DEBUG
 182         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 183                sta->sta.addr, tid);
 184 #endif /* CONFIG_MAC80211_HT_DEBUG */
 185
 186         del_timer_sync(&tid_tx->addba_resp_timer);
 187
 188         /*
 189          * After this packets are no longer handed right through
 190          * to the driver but are put onto tid_tx->pending instead,
 191          * with locking to ensure proper access.
 192          */
 193         clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 194
 195         /*
 196          * There might be a few packets being processed right now (on
 197          * another CPU) that have already gotten past the aggregation
 198          * check when it was still OPERATIONAL and consequently have
 199          * IEEE80211_TX_CTL_AMPDU set. In that case, this code might
 200          * call into the driver at the same time or even before the
 201          * TX paths calls into it, which could confuse the driver.
 202          *
 203          * Wait for all currently running TX paths to finish before
 204          * telling the driver. New packets will not go through since
 205          * the aggregation session is no longer OPERATIONAL.
 206          */
 207         synchronize_net();
 208
 209         tid_tx->stop_initiator = initiator;
 210         tid_tx->tx_stop = tx;
 211
 212         ret = drv_ampdu_action(local, sta->sdata,
 213                                IEEE80211_AMPDU_TX_STOP,
 214                                &sta->sta, tid, NULL, 0);
 215
 216         /* HW shall not deny going back to legacy */
 217         if (WARN_ON(ret)) {
 218                 /*
 219                  * We may have pending packets get stuck in this case...
 220                  * Not bothering with a workaround for now.
 221                  */
 222         }
 223
 224         return ret;
 225 }
 226
 227 /*
 228  * After sending add Block Ack request we activated a timer until
 229  * add Block Ack response will arrive from the recipient.
 230  * If this timer expires sta_addba_resp_timer_expired will be executed.
 231  */
 232 static void sta_addba_resp_timer_expired(unsigned long data)
 233 {
 234         /* not an elegant detour, but there is no choice as the timer passes
 235          * only one argument, and both sta_info and TID are needed, so init
 236          * flow in sta_info_create gives the TID as data, while the timer_to_id
 237          * array gives the sta through container_of */
 238         u16 tid = *(u8 *)data;
 239         struct sta_info *sta = container_of((void *)data,
 240                 struct sta_info, timer_to_tid[tid]);
 241         struct tid_ampdu_tx *tid_tx;
 242
 243         /* check if the TID waits for addBA response */
 244         rcu_read_lock();
 245         tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 246         if (!tid_tx ||
 247             test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 248                 rcu_read_unlock();
 249 #ifdef CONFIG_MAC80211_HT_DEBUG
 250                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 251                                 "(or no longer) expecting addBA response there\n",
 252                         tid);
 253 #endif
 254                 return;
 255         }
 256
 257 #ifdef CONFIG_MAC80211_HT_DEBUG
 258         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 259 #endif
 260
 261         ieee80211_stop_tx_ba_session(&sta->sta, tid);
 262         rcu_read_unlock();
 263 }
 264
 265 static inline int ieee80211_ac_from_tid(int tid)
 266 {
 267         return ieee802_1d_to_ac[tid & 7];
 268 }
 269
 270 /*
 271  * When multiple aggregation sessions on multiple stations
 272  * are being created/destroyed simultaneously, we need to
 273  * refcount the global queue stop caused by that in order
 274  * to not get into a situation where one of the aggregation
 275  * setup or teardown re-enables queues before the other is
 276  * ready to handle that.
 277  *
 278  * These two functions take care of this issue by keeping
 279  * a global "agg_queue_stop" refcount.
 280  */
 281 static void __acquires(agg_queue)
 282 ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
 283 {
 284         int queue = ieee80211_ac_from_tid(tid);
 285
 286         if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
 287                 ieee80211_stop_queue_by_reason(
 288                         &local->hw, queue,
 289                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 290         __acquire(agg_queue);
 291 }
 292
 293 static void __releases(agg_queue)
 294 ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 295 {
 296         int queue = ieee80211_ac_from_tid(tid);
 297
 298         if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
 299                 ieee80211_wake_queue_by_reason(
 300                         &local->hw, queue,
 301                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 302         __release(agg_queue);
 303 }
 304
 305 /*
 306  * splice packets from the STA's pending to the local pending,
 307  * requires a call to ieee80211_agg_splice_finish later
 308  */
 309 static void __acquires(agg_queue)
 310 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 311                              struct tid_ampdu_tx *tid_tx, u16 tid)
 312 {
 313         int queue = ieee80211_ac_from_tid(tid);
 314         unsigned long flags;
 315
 316         ieee80211_stop_queue_agg(local, tid);
 317
 318         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 319                           " from the pending queue\n", tid))
 320                 return;
 321
 322         if (!skb_queue_empty(&tid_tx->pending)) {
 323                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 324                 /* copy over remaining packets */
 325                 skb_queue_splice_tail_init(&tid_tx->pending,
 326                                            &local->pending[queue]);
 327                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 328         }
 329 }
 330
 331 static void __releases(agg_queue)
 332 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 333 {
 334         ieee80211_wake_queue_agg(local, tid);
 335 }
 336
 337 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 338 {
 339         struct tid_ampdu_tx *tid_tx;
 340         struct ieee80211_local *local = sta->local;
 341         struct ieee80211_sub_if_data *sdata = sta->sdata;
 342         u16 start_seq_num;
 343         int ret;
 344
 345         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 346
 347         /*
 348          * Start queuing up packets for this aggregation session.
 349          * We're going to release them once the driver is OK with
 350          * that.
 351          */
 352         clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 353
 354         /*
 355          * Make sure no packets are being processed. This ensures that
 356          * we have a valid starting sequence number and that in-flight
 357          * packets have been flushed out and no packets for this TID
 358          * will go into the driver during the ampdu_action call.
 359          */
 360         synchronize_net();
 361
 362         start_seq_num = sta->tid_seq[tid] >> 4;
 363
 364         ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 365                                &sta->sta, tid, &start_seq_num, 0);
 366         if (ret) {
 367 #ifdef CONFIG_MAC80211_HT_DEBUG
 368                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 369                                         " tid %d\n", tid);
 370 #endif
 371                 spin_lock_bh(&sta->lock);
 372                 ieee80211_agg_splice_packets(local, tid_tx, tid);
 373                 ieee80211_assign_tid_tx(sta, tid, NULL);
 374                 ieee80211_agg_splice_finish(local, tid);
 375                 spin_unlock_bh(&sta->lock);
 376
 377                 kfree_rcu(tid_tx, rcu_head);
 378                 return;
 379         }
 380
 381         /* activate the timer for the recipient's addBA response */
 382         mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 383 #ifdef CONFIG_MAC80211_HT_DEBUG
 384         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 385 #endif
 386
 387         spin_lock_bh(&sta->lock);
 388         sta->ampdu_mlme.addba_req_num[tid]++;
 389         spin_unlock_bh(&sta->lock);
 390
 391         /* send AddBA request */
 392         ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 393                                      tid_tx->dialog_token, start_seq_num,
 394                                      local->hw.max_tx_aggregation_subframes,
 395                                      tid_tx->timeout);
 396 }
 397
 398 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 399                                   u16 timeout)
 400 {
 401         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 402         struct ieee80211_sub_if_data *sdata = sta->sdata;
 403         struct ieee80211_local *local = sdata->local;
 404         struct tid_ampdu_tx *tid_tx;
 405         int ret = 0;
 406
 407         trace_api_start_tx_ba_session(pubsta, tid);
 408
 409         if (WARN_ON(!local->ops->ampdu_action))
 410                 return -EINVAL;
 411
 412         if ((tid >= STA_TID_NUM) ||
 413             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION) ||
 414             (local->hw.flags & IEEE80211_HW_TX_AMPDU_SETUP_IN_HW))
 415                 return -EINVAL;
 416
 417 #ifdef CONFIG_MAC80211_HT_DEBUG
 418         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 419                pubsta->addr, tid);
 420 #endif /* CONFIG_MAC80211_HT_DEBUG */
 421
 422         /*
 423          * The aggregation code is not prepared to handle
 424          * anything but STA/AP due to the BSSID handling.
 425          * IBSS could work in the code but isn't supported
 426          * by drivers or the standard.
 427          */
 428         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 429             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 430             sdata->vif.type != NL80211_IFTYPE_AP)
 431                 return -EINVAL;
 432
 433         if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
 434 #ifdef CONFIG_MAC80211_HT_DEBUG
 435                 printk(KERN_DEBUG "BA sessions blocked. "
 436                        "Denying BA session request\n");
 437 #endif
 438                 return -EINVAL;
 439         }
 440
 441         spin_lock_bh(&sta->lock);
 442
 443         /* we have tried too many times, receiver does not want A-MPDU */
 444         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 445                 ret = -EBUSY;
 446                 goto err_unlock_sta;
 447         }
 448
 449         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 450         /* check if the TID is not in aggregation flow already */
 451         if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
 452 #ifdef CONFIG_MAC80211_HT_DEBUG
 453                 printk(KERN_DEBUG "BA request denied - session is not "
 454                                  "idle on tid %u\n", tid);
 455 #endif /* CONFIG_MAC80211_HT_DEBUG */
 456                 ret = -EAGAIN;
 457                 goto err_unlock_sta;
 458         }
 459
 460         /* prepare A-MPDU MLME for Tx aggregation */
 461         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 462         if (!tid_tx) {
 463                 ret = -ENOMEM;
 464                 goto err_unlock_sta;
 465         }
 466
 467         skb_queue_head_init(&tid_tx->pending);
 468         __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 469
 470         tid_tx->timeout = timeout;
 471
 472         /* Tx timer */
 473         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 474         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 475         init_timer(&tid_tx->addba_resp_timer);
 476
 477         /* assign a dialog token */
 478         sta->ampdu_mlme.dialog_token_allocator++;
 479         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 480
 481         /*
 482          * Finally, assign it to the start array; the work item will
 483          * collect it and move it to the normal array.
 484          */
 485         sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
 486
 487         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 488
 489         /* this flow continues off the work */
 490  err_unlock_sta:
 491         spin_unlock_bh(&sta->lock);
 492         return ret;
 493 }
 494 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 495
 496 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 497                                          struct sta_info *sta, u16 tid)
 498 {
 499         struct tid_ampdu_tx *tid_tx;
 500
 501         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 502
 503         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 504
 505 #ifdef CONFIG_MAC80211_HT_DEBUG
 506         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 507 #endif
 508
 509         drv_ampdu_action(local, sta->sdata,
 510                          IEEE80211_AMPDU_TX_OPERATIONAL,
 511                          &sta->sta, tid, NULL, tid_tx->buf_size);
 512
 513         /*
 514          * synchronize with TX path, while splicing the TX path
 515          * should block so it won't put more packets onto pending.
 516          */
 517         spin_lock_bh(&sta->lock);
 518
 519         ieee80211_agg_splice_packets(local, tid_tx, tid);
 520         /*
 521          * Now mark as operational. This will be visible
 522          * in the TX path, and lets it go lock-free in
 523          * the common case.
 524          */
 525         set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 526         ieee80211_agg_splice_finish(local, tid);
 527
 528         spin_unlock_bh(&sta->lock);
 529 }
 530
 531 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 532 {
 533         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 534         struct ieee80211_local *local = sdata->local;
 535         struct sta_info *sta;
 536         struct tid_ampdu_tx *tid_tx;
 537
 538         trace_api_start_tx_ba_cb(sdata, ra, tid);
 539
 540         if (tid >= STA_TID_NUM) {
 541 #ifdef CONFIG_MAC80211_HT_DEBUG
 542                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 543                                 tid, STA_TID_NUM);
 544 #endif
 545                 return;
 546         }
 547
 548         mutex_lock(&local->sta_mtx);
 549         sta = sta_info_get(sdata, ra);
 550         if (!sta) {
 551                 mutex_unlock(&local->sta_mtx);
 552 #ifdef CONFIG_MAC80211_HT_DEBUG
 553                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 554 #endif
 555                 return;
 556         }
 557
 558         mutex_lock(&sta->ampdu_mlme.mtx);
 559         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 560
 561         if (WARN_ON(!tid_tx)) {
 562 #ifdef CONFIG_MAC80211_HT_DEBUG
 563                 printk(KERN_DEBUG "addBA was not requested!\n");
 564 #endif
 565                 goto unlock;
 566         }
 567
 568         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 569                 goto unlock;
 570
 571         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 572                 ieee80211_agg_tx_operational(local, sta, tid);
 573
 574  unlock:
 575         mutex_unlock(&sta->ampdu_mlme.mtx);
 576         mutex_unlock(&local->sta_mtx);
 577 }
 578
 579 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 580                                       const u8 *ra, u16 tid)
 581 {
 582         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 583         struct ieee80211_local *local = sdata->local;
 584         struct ieee80211_ra_tid *ra_tid;
 585         struct sk_buff *skb = dev_alloc_skb(0);
 586
 587         if (unlikely(!skb))
 588                 return;
 589
 590         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 591         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 592         ra_tid->tid = tid;
 593
 594         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 595         skb_queue_tail(&sdata->skb_queue, skb);
 596         ieee80211_queue_work(&local->hw, &sdata->work);
 597 }
 598 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 599
 600 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 601                                    enum ieee80211_back_parties initiator,
 602                                    bool tx)
 603 {
 604         int ret;
 605
 606         mutex_lock(&sta->ampdu_mlme.mtx);
 607
 608         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator, tx);
 609
 610         mutex_unlock(&sta->ampdu_mlme.mtx);
 611
 612         return ret;
 613 }
 614
 615 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 616 {
 617         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 618         struct ieee80211_sub_if_data *sdata = sta->sdata;
 619         struct ieee80211_local *local = sdata->local;
 620         struct tid_ampdu_tx *tid_tx;
 621         int ret = 0;
 622
 623         trace_api_stop_tx_ba_session(pubsta, tid);
 624
 625         if (!local->ops->ampdu_action)
 626                 return -EINVAL;
 627
 628         if (tid >= STA_TID_NUM)
 629                 return -EINVAL;
 630
 631         spin_lock_bh(&sta->lock);
 632         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 633
 634         if (!tid_tx) {
 635                 ret = -ENOENT;
 636                 goto unlock;
 637         }
 638
 639         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 640                 /* already in progress stopping it */
 641                 ret = 0;
 642                 goto unlock;
 643         }
 644
 645         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 646         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 647
 648  unlock:
 649         spin_unlock_bh(&sta->lock);
 650         return ret;
 651 }
 652 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 653
 654 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 655 {
 656         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 657         struct ieee80211_local *local = sdata->local;
 658         struct sta_info *sta;
 659         struct tid_ampdu_tx *tid_tx;
 660
 661         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 662
 663         if (tid >= STA_TID_NUM) {
 664 #ifdef CONFIG_MAC80211_HT_DEBUG
 665                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 666                                 tid, STA_TID_NUM);
 667 #endif
 668                 return;
 669         }
 670
 671 #ifdef CONFIG_MAC80211_HT_DEBUG
 672         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 673                ra, tid);
 674 #endif /* CONFIG_MAC80211_HT_DEBUG */
 675
 676         mutex_lock(&local->sta_mtx);
 677
 678         sta = sta_info_get(sdata, ra);
 679         if (!sta) {
 680 #ifdef CONFIG_MAC80211_HT_DEBUG
 681                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 682 #endif
 683                 goto unlock;
 684         }
 685
 686         mutex_lock(&sta->ampdu_mlme.mtx);
 687         spin_lock_bh(&sta->lock);
 688         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 689
 690         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 691 #ifdef CONFIG_MAC80211_HT_DEBUG
 692                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 693 #endif
 694                 goto unlock_sta;
 695         }
 696
 697         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 698                 ieee80211_send_delba(sta->sdata, ra, tid,
 699                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 700
 701         /*
 702          * When we get here, the TX path will not be lockless any more wrt.
 703          * aggregation, since the OPERATIONAL bit has long been cleared.
 704          * Thus it will block on getting the lock, if it occurs. So if we
 705          * stop the queue now, we will not get any more packets, and any
 706          * that might be being processed will wait for us here, thereby
 707          * guaranteeing that no packets go to the tid_tx pending queue any
 708          * more.
 709          */
 710
 711         ieee80211_agg_splice_packets(local, tid_tx, tid);
 712
 713         /* future packets must not find the tid_tx struct any more */
 714         ieee80211_assign_tid_tx(sta, tid, NULL);
 715
 716         ieee80211_agg_splice_finish(local, tid);
 717
 718         kfree_rcu(tid_tx, rcu_head);
 719
 720  unlock_sta:
 721         spin_unlock_bh(&sta->lock);
 722         mutex_unlock(&sta->ampdu_mlme.mtx);
 723  unlock:
 724         mutex_unlock(&local->sta_mtx);
 725 }
 726
 727 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 728                                      const u8 *ra, u16 tid)
 729 {
 730         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 731         struct ieee80211_local *local = sdata->local;
 732         struct ieee80211_ra_tid *ra_tid;
 733         struct sk_buff *skb = dev_alloc_skb(0);
 734
 735         if (unlikely(!skb))
 736                 return;
 737
 738         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 739         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 740         ra_tid->tid = tid;
 741
 742         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 743         skb_queue_tail(&sdata->skb_queue, skb);
 744         ieee80211_queue_work(&local->hw, &sdata->work);
 745 }
 746 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 747
 748
 749 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 750                                   struct sta_info *sta,
 751                                   struct ieee80211_mgmt *mgmt,
 752                                   size_t len)
 753 {
 754         struct tid_ampdu_tx *tid_tx;
 755         u16 capab, tid;
 756         u8 buf_size;
 757
 758         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 759         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 760         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 761
 762         mutex_lock(&sta->ampdu_mlme.mtx);
 763
 764         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 765         if (!tid_tx)
 766                 goto out;
 767
 768         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 769 #ifdef CONFIG_MAC80211_HT_DEBUG
 770                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 771 #endif
 772                 goto out;
 773         }
 774
 775         del_timer_sync(&tid_tx->addba_resp_timer);
 776
 777 #ifdef CONFIG_MAC80211_HT_DEBUG
 778         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 779 #endif
 780
 781         /*
 782          * addba_resp_timer may have fired before we got here, and
 783          * caused WANT_STOP to be set. If the stop then was already
 784          * processed further, STOPPING might be set.
 785          */
 786         if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
 787             test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 788 #ifdef CONFIG_MAC80211_HT_DEBUG
 789                 printk(KERN_DEBUG
 790                        "got addBA resp for tid %d but we already gave up\n",
 791                        tid);
 792 #endif
 793                 goto out;
 794         }
 795
 796         /*
 797          * IEEE 802.11-2007 7.3.1.14:
 798          * In an ADDBA Response frame, when the Status Code field
 799          * is set to 0, the Buffer Size subfield is set to a value
 800          * of at least 1.
 801          */
 802         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 803                         == WLAN_STATUS_SUCCESS && buf_size) {
 804                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 805                                      &tid_tx->state)) {
 806                         /* ignore duplicate response */
 807                         goto out;
 808                 }
 809
 810                 tid_tx->buf_size = buf_size;
 811
 812                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 813                         ieee80211_agg_tx_operational(local, sta, tid);
 814
 815                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 816         } else {
 817                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
 818                                                 true);
 819         }
 820
 821  out:
 822         mutex_unlock(&sta->ampdu_mlme.mtx);
 823 }