net/mac80211/agg-tx.c

   1 /*
   2  * HT handling
   3  *
   4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5  * Copyright 2002-2005, Instant802 Networks, Inc.
   6  * Copyright 2005-2006, Devicescape Software, Inc.
   7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9  * Copyright 2007-2010, Intel Corporation
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/ieee80211.h>
  17 #include <linux/slab.h>
  18 #include <linux/export.h>
  19 #include <net/mac80211.h>
  20 #include "ieee80211_i.h"
  21 #include "driver-ops.h"
  22 #include "wme.h"
  23
  24 /**
  25  * DOC: TX A-MPDU aggregation
  26  *
  27  * Aggregation on the TX side requires setting the hardware flag
  28  * %IEEE80211_HW_AMPDU_AGGREGATION. The driver will then be handed
  29  * packets with a flag indicating A-MPDU aggregation. The driver
  30  * or device is responsible for actually aggregating the frames,
  31  * as well as deciding how many and which to aggregate.
  32  *
  33  * When TX aggregation is started by some subsystem (usually the rate
  34  * control algorithm would be appropriate) by calling the
  35  * ieee80211_start_tx_ba_session() function, the driver will be
  36  * notified via its @ampdu_action function, with the
  37  * %IEEE80211_AMPDU_TX_START action.
  38  *
  39  * In response to that, the driver is later required to call the
  40  * ieee80211_start_tx_ba_cb_irqsafe() function, which will really
  41  * start the aggregation session after the peer has also responded.
  42  * If the peer responds negatively, the session will be stopped
  43  * again right away. Note that it is possible for the aggregation
  44  * session to be stopped before the driver has indicated that it
  45  * is done setting it up, in which case it must not indicate the
  46  * setup completion.
  47  *
  48  * Also note that, since we also need to wait for a response from
  49  * the peer, the driver is notified of the completion of the
  50  * handshake by the %IEEE80211_AMPDU_TX_OPERATIONAL action to the
  51  * @ampdu_action callback.
  52  *
  53  * Similarly, when the aggregation session is stopped by the peer
  54  * or something calling ieee80211_stop_tx_ba_session(), the driver's
  55  * @ampdu_action function will be called with the action
  56  * %IEEE80211_AMPDU_TX_STOP. In this case, the call must not fail,
  57  * and the driver must later call ieee80211_stop_tx_ba_cb_irqsafe().
  58  * Note that the sta can get destroyed before the BA tear down is
  59  * complete.
  60  */
  61
  62 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
  63                                          const u8 *da, u16 tid,
  64                                          u8 dialog_token, u16 start_seq_num,
  65                                          u16 agg_size, u16 timeout)
  66 {
  67         struct ieee80211_local *local = sdata->local;
  68         struct sk_buff *skb;
  69         struct ieee80211_mgmt *mgmt;
  70         u16 capab;
  71
  72         skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
  73
  74         if (!skb)
  75                 return;
  76
  77         skb_reserve(skb, local->hw.extra_tx_headroom);
  78         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
  79         memset(mgmt, 0, 24);
  80         memcpy(mgmt->da, da, ETH_ALEN);
  81         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
  82         if (sdata->vif.type == NL80211_IFTYPE_AP ||
  83             sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
  84             sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
  85                 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
  86         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
  87                 memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
  88         else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
  89                 memcpy(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN);
  90
  91         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  92                                           IEEE80211_STYPE_ACTION);
  93
  94         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
  95
  96         mgmt->u.action.category = WLAN_CATEGORY_BACK;
  97         mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
  98
  99         mgmt->u.action.u.addba_req.dialog_token = dialog_token;
 100         capab = (u16)(1 << 1);          /* bit 1 aggregation policy */
 101         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
 102         capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
 103
 104         mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
 105
 106         mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
 107         mgmt->u.action.u.addba_req.start_seq_num =
 108                                         cpu_to_le16(start_seq_num << 4);
 109
 110         ieee80211_tx_skb_tid(sdata, skb, tid);
 111 }
 112
 113 void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
 114 {
 115         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 116         struct ieee80211_local *local = sdata->local;
 117         struct sk_buff *skb;
 118         struct ieee80211_bar *bar;
 119         u16 bar_control = 0;
 120
 121         skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
 122         if (!skb)
 123                 return;
 124
 125         skb_reserve(skb, local->hw.extra_tx_headroom);
 126         bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
 127         memset(bar, 0, sizeof(*bar));
 128         bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
 129                                          IEEE80211_STYPE_BACK_REQ);
 130         memcpy(bar->ra, ra, ETH_ALEN);
 131         memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
 132         bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 133         bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
 134         bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
 135         bar->control = cpu_to_le16(bar_control);
 136         bar->start_seq_num = cpu_to_le16(ssn);
 137
 138         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 139         ieee80211_tx_skb_tid(sdata, skb, tid);
 140 }
 141 EXPORT_SYMBOL(ieee80211_send_bar);
 142
 143 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
 144                              struct tid_ampdu_tx *tid_tx)
 145 {
 146         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 147         lockdep_assert_held(&sta->lock);
 148         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 149 }
 150
 151 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 152                                     enum ieee80211_back_parties initiator,
 153                                     bool tx)
 154 {
 155         struct ieee80211_local *local = sta->local;
 156         struct tid_ampdu_tx *tid_tx;
 157         int ret;
 158
 159         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 160
 161         spin_lock_bh(&sta->lock);
 162
 163         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 164         if (!tid_tx) {
 165                 spin_unlock_bh(&sta->lock);
 166                 return -ENOENT;
 167         }
 168
 169         /* if we're already stopping ignore any new requests to stop */
 170         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 171                 spin_unlock_bh(&sta->lock);
 172                 return -EALREADY;
 173         }
 174
 175         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 176                 /* not even started yet! */
 177                 ieee80211_assign_tid_tx(sta, tid, NULL);
 178                 spin_unlock_bh(&sta->lock);
 179                 kfree_rcu(tid_tx, rcu_head);
 180                 return 0;
 181         }
 182
 183         set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 184
 185         spin_unlock_bh(&sta->lock);
 186
 187 #ifdef CONFIG_MAC80211_HT_DEBUG
 188         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 189                sta->sta.addr, tid);
 190 #endif /* CONFIG_MAC80211_HT_DEBUG */
 191
 192         del_timer_sync(&tid_tx->addba_resp_timer);
 193         del_timer_sync(&tid_tx->session_timer);
 194
 195         /*
 196          * After this packets are no longer handed right through
 197          * to the driver but are put onto tid_tx->pending instead,
 198          * with locking to ensure proper access.
 199          */
 200         clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 201
 202         /*
 203          * There might be a few packets being processed right now (on
 204          * another CPU) that have already gotten past the aggregation
 205          * check when it was still OPERATIONAL and consequently have
 206          * IEEE80211_TX_CTL_AMPDU set. In that case, this code might
 207          * call into the driver at the same time or even before the
 208          * TX paths calls into it, which could confuse the driver.
 209          *
 210          * Wait for all currently running TX paths to finish before
 211          * telling the driver. New packets will not go through since
 212          * the aggregation session is no longer OPERATIONAL.
 213          */
 214         synchronize_net();
 215
 216         tid_tx->stop_initiator = initiator;
 217         tid_tx->tx_stop = tx;
 218
 219         ret = drv_ampdu_action(local, sta->sdata,
 220                                IEEE80211_AMPDU_TX_STOP,
 221                                &sta->sta, tid, NULL, 0);
 222
 223         /* HW shall not deny going back to legacy */
 224         if (WARN_ON(ret)) {
 225                 /*
 226                  * We may have pending packets get stuck in this case...
 227                  * Not bothering with a workaround for now.
 228                  */
 229         }
 230
 231         return ret;
 232 }
 233
 234 /*
 235  * After sending add Block Ack request we activated a timer until
 236  * add Block Ack response will arrive from the recipient.
 237  * If this timer expires sta_addba_resp_timer_expired will be executed.
 238  */
 239 static void sta_addba_resp_timer_expired(unsigned long data)
 240 {
 241         /* not an elegant detour, but there is no choice as the timer passes
 242          * only one argument, and both sta_info and TID are needed, so init
 243          * flow in sta_info_create gives the TID as data, while the timer_to_id
 244          * array gives the sta through container_of */
 245         u16 tid = *(u8 *)data;
 246         struct sta_info *sta = container_of((void *)data,
 247                 struct sta_info, timer_to_tid[tid]);
 248         struct tid_ampdu_tx *tid_tx;
 249
 250         /* check if the TID waits for addBA response */
 251         rcu_read_lock();
 252         tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 253         if (!tid_tx ||
 254             test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 255                 rcu_read_unlock();
 256 #ifdef CONFIG_MAC80211_HT_DEBUG
 257                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 258                                 "(or no longer) expecting addBA response there\n",
 259                         tid);
 260 #endif
 261                 return;
 262         }
 263
 264 #ifdef CONFIG_MAC80211_HT_DEBUG
 265         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 266 #endif
 267
 268         ieee80211_stop_tx_ba_session(&sta->sta, tid);
 269         rcu_read_unlock();
 270 }
 271
 272 static inline int ieee80211_ac_from_tid(int tid)
 273 {
 274         return ieee802_1d_to_ac[tid & 7];
 275 }
 276
 277 /*
 278  * When multiple aggregation sessions on multiple stations
 279  * are being created/destroyed simultaneously, we need to
 280  * refcount the global queue stop caused by that in order
 281  * to not get into a situation where one of the aggregation
 282  * setup or teardown re-enables queues before the other is
 283  * ready to handle that.
 284  *
 285  * These two functions take care of this issue by keeping
 286  * a global "agg_queue_stop" refcount.
 287  */
 288 static void __acquires(agg_queue)
 289 ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
 290 {
 291         int queue = ieee80211_ac_from_tid(tid);
 292
 293         if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
 294                 ieee80211_stop_queue_by_reason(
 295                         &local->hw, queue,
 296                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 297         __acquire(agg_queue);
 298 }
 299
 300 static void __releases(agg_queue)
 301 ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 302 {
 303         int queue = ieee80211_ac_from_tid(tid);
 304
 305         if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
 306                 ieee80211_wake_queue_by_reason(
 307                         &local->hw, queue,
 308                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 309         __release(agg_queue);
 310 }
 311
 312 /*
 313  * splice packets from the STA's pending to the local pending,
 314  * requires a call to ieee80211_agg_splice_finish later
 315  */
 316 static void __acquires(agg_queue)
 317 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 318                              struct tid_ampdu_tx *tid_tx, u16 tid)
 319 {
 320         int queue = ieee80211_ac_from_tid(tid);
 321         unsigned long flags;
 322
 323         ieee80211_stop_queue_agg(local, tid);
 324
 325         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 326                           " from the pending queue\n", tid))
 327                 return;
 328
 329         if (!skb_queue_empty(&tid_tx->pending)) {
 330                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 331                 /* copy over remaining packets */
 332                 skb_queue_splice_tail_init(&tid_tx->pending,
 333                                            &local->pending[queue]);
 334                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 335         }
 336 }
 337
 338 static void __releases(agg_queue)
 339 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 340 {
 341         ieee80211_wake_queue_agg(local, tid);
 342 }
 343
 344 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 345 {
 346         struct tid_ampdu_tx *tid_tx;
 347         struct ieee80211_local *local = sta->local;
 348         struct ieee80211_sub_if_data *sdata = sta->sdata;
 349         u16 start_seq_num;
 350         int ret;
 351
 352         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 353
 354         /*
 355          * Start queuing up packets for this aggregation session.
 356          * We're going to release them once the driver is OK with
 357          * that.
 358          */
 359         clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 360
 361         /*
 362          * Make sure no packets are being processed. This ensures that
 363          * we have a valid starting sequence number and that in-flight
 364          * packets have been flushed out and no packets for this TID
 365          * will go into the driver during the ampdu_action call.
 366          */
 367         synchronize_net();
 368
 369         start_seq_num = sta->tid_seq[tid] >> 4;
 370
 371         ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 372                                &sta->sta, tid, &start_seq_num, 0);
 373         if (ret) {
 374 #ifdef CONFIG_MAC80211_HT_DEBUG
 375                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 376                                         " tid %d\n", tid);
 377 #endif
 378                 spin_lock_bh(&sta->lock);
 379                 ieee80211_agg_splice_packets(local, tid_tx, tid);
 380                 ieee80211_assign_tid_tx(sta, tid, NULL);
 381                 ieee80211_agg_splice_finish(local, tid);
 382                 spin_unlock_bh(&sta->lock);
 383
 384                 kfree_rcu(tid_tx, rcu_head);
 385                 return;
 386         }
 387
 388         /* activate the timer for the recipient's addBA response */
 389         mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 390 #ifdef CONFIG_MAC80211_HT_DEBUG
 391         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 392 #endif
 393
 394         spin_lock_bh(&sta->lock);
 395         sta->ampdu_mlme.last_addba_req_time[tid] = jiffies;
 396         sta->ampdu_mlme.addba_req_num[tid]++;
 397         spin_unlock_bh(&sta->lock);
 398
 399         /* send AddBA request */
 400         ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 401                                      tid_tx->dialog_token, start_seq_num,
 402                                      local->hw.max_tx_aggregation_subframes,
 403                                      tid_tx->timeout);
 404 }
 405
 406 /*
 407  * After accepting the AddBA Response we activated a timer,
 408  * resetting it after each frame that we send.
 409  */
 410 static void sta_tx_agg_session_timer_expired(unsigned long data)
 411 {
 412         /* not an elegant detour, but there is no choice as the timer passes
 413          * only one argument, and various sta_info are needed here, so init
 414          * flow in sta_info_create gives the TID as data, while the timer_to_id
 415          * array gives the sta through container_of */
 416         u8 *ptid = (u8 *)data;
 417         u8 *timer_to_id = ptid - *ptid;
 418         struct sta_info *sta = container_of(timer_to_id, struct sta_info,
 419                                          timer_to_tid[0]);
 420
 421 #ifdef CONFIG_MAC80211_HT_DEBUG
 422         printk(KERN_DEBUG "tx session timer expired on tid %d\n", (u16)*ptid);
 423 #endif
 424
 425         ieee80211_stop_tx_ba_session(&sta->sta, *ptid);
 426 }
 427
 428 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 429                                   u16 timeout)
 430 {
 431         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 432         struct ieee80211_sub_if_data *sdata = sta->sdata;
 433         struct ieee80211_local *local = sdata->local;
 434         struct tid_ampdu_tx *tid_tx;
 435         int ret = 0;
 436
 437         trace_api_start_tx_ba_session(pubsta, tid);
 438
 439         if (WARN_ON(!local->ops->ampdu_action))
 440                 return -EINVAL;
 441
 442         if ((tid >= STA_TID_NUM) ||
 443             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION) ||
 444             (local->hw.flags & IEEE80211_HW_TX_AMPDU_SETUP_IN_HW))
 445                 return -EINVAL;
 446
 447 #ifdef CONFIG_MAC80211_HT_DEBUG
 448         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 449                pubsta->addr, tid);
 450 #endif /* CONFIG_MAC80211_HT_DEBUG */
 451
 452         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 453             sdata->vif.type != NL80211_IFTYPE_MESH_POINT &&
 454             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 455             sdata->vif.type != NL80211_IFTYPE_AP &&
 456             sdata->vif.type != NL80211_IFTYPE_ADHOC)
 457                 return -EINVAL;
 458
 459         if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
 460 #ifdef CONFIG_MAC80211_HT_DEBUG
 461                 printk(KERN_DEBUG "BA sessions blocked. "
 462                        "Denying BA session request\n");
 463 #endif
 464                 return -EINVAL;
 465         }
 466
 467         /*
 468          * 802.11n-2009 11.5.1.1: If the initiating STA is an HT STA, is a
 469          * member of an IBSS, and has no other existing Block Ack agreement
 470          * with the recipient STA, then the initiating STA shall transmit a
 471          * Probe Request frame to the recipient STA and shall not transmit an
 472          * ADDBA Request frame unless it receives a Probe Response frame
 473          * from the recipient within dot11ADDBAFailureTimeout.
 474          *
 475          * The probe request mechanism for ADDBA is currently not implemented,
 476          * but we only build up Block Ack session with HT STAs. This information
 477          * is set when we receive a bss info from a probe response or a beacon.
 478          */
 479         if (sta->sdata->vif.type == NL80211_IFTYPE_ADHOC &&
 480             !sta->sta.ht_cap.ht_supported) {
 481 #ifdef CONFIG_MAC80211_HT_DEBUG
 482                 printk(KERN_DEBUG "BA request denied - IBSS STA %pM"
 483                        "does not advertise HT support\n", pubsta->addr);
 484 #endif /* CONFIG_MAC80211_HT_DEBUG */
 485                 return -EINVAL;
 486         }
 487
 488         spin_lock_bh(&sta->lock);
 489
 490         /* we have tried too many times, receiver does not want A-MPDU */
 491         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 492                 ret = -EBUSY;
 493                 goto err_unlock_sta;
 494         }
 495
 496         /*
 497          * if we have tried more than HT_AGG_BURST_RETRIES times we
 498          * will spread our requests in time to avoid stalling connection
 499          * for too long
 500          */
 501         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_BURST_RETRIES &&
 502             time_before(jiffies, sta->ampdu_mlme.last_addba_req_time[tid] +
 503                         HT_AGG_RETRIES_PERIOD)) {
 504 #ifdef CONFIG_MAC80211_HT_DEBUG
 505                 printk(KERN_DEBUG "BA request denied - "
 506                        "waiting a grace period after %d failed requests "
 507                        "on tid %u\n",
 508                        sta->ampdu_mlme.addba_req_num[tid], tid);
 509 #endif /* CONFIG_MAC80211_HT_DEBUG */
 510                 ret = -EBUSY;
 511                 goto err_unlock_sta;
 512         }
 513
 514         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 515         /* check if the TID is not in aggregation flow already */
 516         if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
 517 #ifdef CONFIG_MAC80211_HT_DEBUG
 518                 printk(KERN_DEBUG "BA request denied - session is not "
 519                                  "idle on tid %u\n", tid);
 520 #endif /* CONFIG_MAC80211_HT_DEBUG */
 521                 ret = -EAGAIN;
 522                 goto err_unlock_sta;
 523         }
 524
 525         /* prepare A-MPDU MLME for Tx aggregation */
 526         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 527         if (!tid_tx) {
 528                 ret = -ENOMEM;
 529                 goto err_unlock_sta;
 530         }
 531
 532         skb_queue_head_init(&tid_tx->pending);
 533         __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 534
 535         tid_tx->timeout = timeout;
 536
 537         /* response timer */
 538         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 539         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 540         init_timer(&tid_tx->addba_resp_timer);
 541
 542         /* tx timer */
 543         tid_tx->session_timer.function = sta_tx_agg_session_timer_expired;
 544         tid_tx->session_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 545         init_timer(&tid_tx->session_timer);
 546
 547         /* assign a dialog token */
 548         sta->ampdu_mlme.dialog_token_allocator++;
 549         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 550
 551         /*
 552          * Finally, assign it to the start array; the work item will
 553          * collect it and move it to the normal array.
 554          */
 555         sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
 556
 557         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 558
 559         /* this flow continues off the work */
 560  err_unlock_sta:
 561         spin_unlock_bh(&sta->lock);
 562         return ret;
 563 }
 564 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 565
 566 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 567                                          struct sta_info *sta, u16 tid)
 568 {
 569         struct tid_ampdu_tx *tid_tx;
 570
 571         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 572
 573         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 574
 575 #ifdef CONFIG_MAC80211_HT_DEBUG
 576         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 577 #endif
 578
 579         drv_ampdu_action(local, sta->sdata,
 580                          IEEE80211_AMPDU_TX_OPERATIONAL,
 581                          &sta->sta, tid, NULL, tid_tx->buf_size);
 582
 583         /*
 584          * synchronize with TX path, while splicing the TX path
 585          * should block so it won't put more packets onto pending.
 586          */
 587         spin_lock_bh(&sta->lock);
 588
 589         ieee80211_agg_splice_packets(local, tid_tx, tid);
 590         /*
 591          * Now mark as operational. This will be visible
 592          * in the TX path, and lets it go lock-free in
 593          * the common case.
 594          */
 595         set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 596         ieee80211_agg_splice_finish(local, tid);
 597
 598         spin_unlock_bh(&sta->lock);
 599 }
 600
 601 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 602 {
 603         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 604         struct ieee80211_local *local = sdata->local;
 605         struct sta_info *sta;
 606         struct tid_ampdu_tx *tid_tx;
 607
 608         trace_api_start_tx_ba_cb(sdata, ra, tid);
 609
 610         if (tid >= STA_TID_NUM) {
 611 #ifdef CONFIG_MAC80211_HT_DEBUG
 612                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 613                                 tid, STA_TID_NUM);
 614 #endif
 615                 return;
 616         }
 617
 618         mutex_lock(&local->sta_mtx);
 619         sta = sta_info_get_bss(sdata, ra);
 620         if (!sta) {
 621                 mutex_unlock(&local->sta_mtx);
 622 #ifdef CONFIG_MAC80211_HT_DEBUG
 623                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 624 #endif
 625                 return;
 626         }
 627
 628         mutex_lock(&sta->ampdu_mlme.mtx);
 629         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 630
 631         if (WARN_ON(!tid_tx)) {
 632 #ifdef CONFIG_MAC80211_HT_DEBUG
 633                 printk(KERN_DEBUG "addBA was not requested!\n");
 634 #endif
 635                 goto unlock;
 636         }
 637
 638         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 639                 goto unlock;
 640
 641         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 642                 ieee80211_agg_tx_operational(local, sta, tid);
 643
 644  unlock:
 645         mutex_unlock(&sta->ampdu_mlme.mtx);
 646         mutex_unlock(&local->sta_mtx);
 647 }
 648
 649 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 650                                       const u8 *ra, u16 tid)
 651 {
 652         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 653         struct ieee80211_local *local = sdata->local;
 654         struct ieee80211_ra_tid *ra_tid;
 655         struct sk_buff *skb = dev_alloc_skb(0);
 656
 657         if (unlikely(!skb))
 658                 return;
 659
 660         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 661         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 662         ra_tid->tid = tid;
 663
 664         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 665         skb_queue_tail(&sdata->skb_queue, skb);
 666         ieee80211_queue_work(&local->hw, &sdata->work);
 667 }
 668 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 669
 670 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 671                                    enum ieee80211_back_parties initiator,
 672                                    bool tx)
 673 {
 674         int ret;
 675
 676         mutex_lock(&sta->ampdu_mlme.mtx);
 677
 678         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator, tx);
 679
 680         mutex_unlock(&sta->ampdu_mlme.mtx);
 681
 682         return ret;
 683 }
 684
 685 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 686 {
 687         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 688         struct ieee80211_sub_if_data *sdata = sta->sdata;
 689         struct ieee80211_local *local = sdata->local;
 690         struct tid_ampdu_tx *tid_tx;
 691         int ret = 0;
 692
 693         trace_api_stop_tx_ba_session(pubsta, tid);
 694
 695         if (!local->ops->ampdu_action)
 696                 return -EINVAL;
 697
 698         if (tid >= STA_TID_NUM)
 699                 return -EINVAL;
 700
 701         spin_lock_bh(&sta->lock);
 702         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 703
 704         if (!tid_tx) {
 705                 ret = -ENOENT;
 706                 goto unlock;
 707         }
 708
 709         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 710                 /* already in progress stopping it */
 711                 ret = 0;
 712                 goto unlock;
 713         }
 714
 715         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 716         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 717
 718  unlock:
 719         spin_unlock_bh(&sta->lock);
 720         return ret;
 721 }
 722 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 723
 724 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 725 {
 726         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 727         struct ieee80211_local *local = sdata->local;
 728         struct sta_info *sta;
 729         struct tid_ampdu_tx *tid_tx;
 730
 731         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 732
 733         if (tid >= STA_TID_NUM) {
 734 #ifdef CONFIG_MAC80211_HT_DEBUG
 735                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 736                                 tid, STA_TID_NUM);
 737 #endif
 738                 return;
 739         }
 740
 741 #ifdef CONFIG_MAC80211_HT_DEBUG
 742         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 743                ra, tid);
 744 #endif /* CONFIG_MAC80211_HT_DEBUG */
 745
 746         mutex_lock(&local->sta_mtx);
 747
 748         sta = sta_info_get_bss(sdata, ra);
 749         if (!sta) {
 750 #ifdef CONFIG_MAC80211_HT_DEBUG
 751                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 752 #endif
 753                 goto unlock;
 754         }
 755
 756         mutex_lock(&sta->ampdu_mlme.mtx);
 757         spin_lock_bh(&sta->lock);
 758         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 759
 760         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 761 #ifdef CONFIG_MAC80211_HT_DEBUG
 762                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 763 #endif
 764                 goto unlock_sta;
 765         }
 766
 767         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 768                 ieee80211_send_delba(sta->sdata, ra, tid,
 769                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 770
 771         /*
 772          * When we get here, the TX path will not be lockless any more wrt.
 773          * aggregation, since the OPERATIONAL bit has long been cleared.
 774          * Thus it will block on getting the lock, if it occurs. So if we
 775          * stop the queue now, we will not get any more packets, and any
 776          * that might be being processed will wait for us here, thereby
 777          * guaranteeing that no packets go to the tid_tx pending queue any
 778          * more.
 779          */
 780
 781         ieee80211_agg_splice_packets(local, tid_tx, tid);
 782
 783         /* future packets must not find the tid_tx struct any more */
 784         ieee80211_assign_tid_tx(sta, tid, NULL);
 785
 786         ieee80211_agg_splice_finish(local, tid);
 787
 788         kfree_rcu(tid_tx, rcu_head);
 789
 790  unlock_sta:
 791         spin_unlock_bh(&sta->lock);
 792         mutex_unlock(&sta->ampdu_mlme.mtx);
 793  unlock:
 794         mutex_unlock(&local->sta_mtx);
 795 }
 796
 797 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 798                                      const u8 *ra, u16 tid)
 799 {
 800         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 801         struct ieee80211_local *local = sdata->local;
 802         struct ieee80211_ra_tid *ra_tid;
 803         struct sk_buff *skb = dev_alloc_skb(0);
 804
 805         if (unlikely(!skb))
 806                 return;
 807
 808         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 809         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 810         ra_tid->tid = tid;
 811
 812         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 813         skb_queue_tail(&sdata->skb_queue, skb);
 814         ieee80211_queue_work(&local->hw, &sdata->work);
 815 }
 816 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 817
 818
 819 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 820                                   struct sta_info *sta,
 821                                   struct ieee80211_mgmt *mgmt,
 822                                   size_t len)
 823 {
 824         struct tid_ampdu_tx *tid_tx;
 825         u16 capab, tid;
 826         u8 buf_size;
 827
 828         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 829         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 830         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 831
 832         mutex_lock(&sta->ampdu_mlme.mtx);
 833
 834         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 835         if (!tid_tx)
 836                 goto out;
 837
 838         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 839 #ifdef CONFIG_MAC80211_HT_DEBUG
 840                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 841 #endif
 842                 goto out;
 843         }
 844
 845         del_timer_sync(&tid_tx->addba_resp_timer);
 846
 847 #ifdef CONFIG_MAC80211_HT_DEBUG
 848         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 849 #endif
 850
 851         /*
 852          * addba_resp_timer may have fired before we got here, and
 853          * caused WANT_STOP to be set. If the stop then was already
 854          * processed further, STOPPING might be set.
 855          */
 856         if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
 857             test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 858 #ifdef CONFIG_MAC80211_HT_DEBUG
 859                 printk(KERN_DEBUG
 860                        "got addBA resp for tid %d but we already gave up\n",
 861                        tid);
 862 #endif
 863                 goto out;
 864         }
 865
 866         /*
 867          * IEEE 802.11-2007 7.3.1.14:
 868          * In an ADDBA Response frame, when the Status Code field
 869          * is set to 0, the Buffer Size subfield is set to a value
 870          * of at least 1.
 871          */
 872         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 873                         == WLAN_STATUS_SUCCESS && buf_size) {
 874                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 875                                      &tid_tx->state)) {
 876                         /* ignore duplicate response */
 877                         goto out;
 878                 }
 879
 880                 tid_tx->buf_size = buf_size;
 881
 882                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 883                         ieee80211_agg_tx_operational(local, sta, tid);
 884
 885                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 886
 887                 if (tid_tx->timeout)
 888                         mod_timer(&tid_tx->session_timer,
 889                                   TU_TO_EXP_TIME(tid_tx->timeout));
 890
 891         } else {
 892                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
 893                                                 true);
 894         }
 895
 896  out:
 897         mutex_unlock(&sta->ampdu_mlme.mtx);
 898 }