mac80211/agg-rx.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * HT handling
   4  *
   5  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   6  * Copyright 2002-2005, Instant802 Networks, Inc.
   7  * Copyright 2005-2006, Devicescape Software, Inc.
   8  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   9  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
  10  * Copyright 2007-2010, Intel Corporation
  11  * Copyright(c) 2015-2017 Intel Deutschland GmbH
  12  * Copyright (C) 2018-2023 Intel Corporation
  13  */
  14
  15 /**
  16  * DOC: RX A-MPDU aggregation
  17  *
  18  * Aggregation on the RX side requires only implementing the
  19  * @ampdu_action callback that is invoked to start/stop any
  20  * block-ack sessions for RX aggregation.
  21  *
  22  * When RX aggregation is started by the peer, the driver is
  23  * notified via @ampdu_action function, with the
  24  * %IEEE80211_AMPDU_RX_START action, and may reject the request
  25  * in which case a negative response is sent to the peer, if it
  26  * accepts it a positive response is sent.
  27  *
  28  * While the session is active, the device/driver are required
  29  * to de-aggregate frames and pass them up one by one to mac80211,
  30  * which will handle the reorder buffer.
  31  *
  32  * When the aggregation session is stopped again by the peer or
  33  * ourselves, the driver's @ampdu_action function will be called
  34  * with the action %IEEE80211_AMPDU_RX_STOP. In this case, the
  35  * call must not fail.
  36  */
  37
  38 #include <linux/ieee80211.h>
  39 #include <linux/slab.h>
  40 #include <linux/export.h>
  41 #include <net/mac80211.h>
  42 #include "ieee80211_i.h"
  43 #include "driver-ops.h"
  44
  45 static void ieee80211_free_tid_rx(struct rcu_head *h)
  46 {
  47         struct tid_ampdu_rx *tid_rx =
  48                 container_of(h, struct tid_ampdu_rx, rcu_head);
  49         int i;
  50
  51         for (i = 0; i < tid_rx->buf_size; i++)
  52                 __skb_queue_purge(&tid_rx->reorder_buf[i]);
  53         kfree(tid_rx->reorder_buf);
  54         kfree(tid_rx->reorder_time);
  55         kfree(tid_rx);
  56 }
  57
  58 void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
  59                                     u16 initiator, u16 reason, bool tx)
  60 {
  61         struct ieee80211_local *local = sta->local;
  62         struct tid_ampdu_rx *tid_rx;
  63         struct ieee80211_ampdu_params params = {
  64                 .sta = &sta->sta,
  65                 .action = IEEE80211_AMPDU_RX_STOP,
  66                 .tid = tid,
  67                 .amsdu = false,
  68                 .timeout = 0,
  69                 .ssn = 0,
  70         };
  71
  72         lockdep_assert_wiphy(sta->local->hw.wiphy);
  73
  74         tid_rx = rcu_dereference_protected(sta->ampdu_mlme.tid_rx[tid],
  75                                         lockdep_is_held(&sta->local->hw.wiphy->mtx));
  76
  77         if (!test_bit(tid, sta->ampdu_mlme.agg_session_valid))
  78                 return;
  79
  80         RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
  81         __clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
  82
  83         ht_dbg(sta->sdata,
  84                "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
  85                sta->sta.addr, tid,
  86                initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
  87                (int)reason);
  88
  89         if (drv_ampdu_action(local, sta->sdata, &params))
  90                 sdata_info(sta->sdata,
  91                            "HW problem - can not stop rx aggregation for %pM tid %d\n",
  92                            sta->sta.addr, tid);
  93
  94         /* check if this is a self generated aggregation halt */
  95         if (initiator == WLAN_BACK_RECIPIENT && tx)
  96                 ieee80211_send_delba(sta->sdata, sta->sta.addr,
  97                                      tid, WLAN_BACK_RECIPIENT, reason);
  98
  99         /*
 100          * return here in case tid_rx is not assigned - which will happen if
 101          * IEEE80211_HW_SUPPORTS_REORDERING_BUFFER is set.
 102          */
 103         if (!tid_rx)
 104                 return;
 105
 106         del_timer_sync(&tid_rx->session_timer);
 107
 108         /* make sure ieee80211_sta_reorder_release() doesn't re-arm the timer */
 109         spin_lock_bh(&tid_rx->reorder_lock);
 110         tid_rx->removed = true;
 111         spin_unlock_bh(&tid_rx->reorder_lock);
 112         del_timer_sync(&tid_rx->reorder_timer);
 113
 114         call_rcu(&tid_rx->rcu_head, ieee80211_free_tid_rx);
 115 }
 116
 117 void ieee80211_stop_rx_ba_session(struct ieee80211_vif *vif, u16 ba_rx_bitmap,
 118                                   const u8 *addr)
 119 {
 120         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 121         struct sta_info *sta;
 122         int i;
 123
 124         rcu_read_lock();
 125         sta = sta_info_get_bss(sdata, addr);
 126         if (!sta) {
 127                 rcu_read_unlock();
 128                 return;
 129         }
 130
 131         for (i = 0; i < IEEE80211_NUM_TIDS; i++)
 132                 if (ba_rx_bitmap & BIT(i))
 133                         set_bit(i, sta->ampdu_mlme.tid_rx_stop_requested);
 134
 135         wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);
 136         rcu_read_unlock();
 137 }
 138 EXPORT_SYMBOL(ieee80211_stop_rx_ba_session);
 139
 140 /*
 141  * After accepting the AddBA Request we activated a timer,
 142  * resetting it after each frame that arrives from the originator.
 143  */
 144 static void sta_rx_agg_session_timer_expired(struct timer_list *t)
 145 {
 146         struct tid_ampdu_rx *tid_rx = from_timer(tid_rx, t, session_timer);
 147         struct sta_info *sta = tid_rx->sta;
 148         u8 tid = tid_rx->tid;
 149         unsigned long timeout;
 150
 151         timeout = tid_rx->last_rx + TU_TO_JIFFIES(tid_rx->timeout);
 152         if (time_is_after_jiffies(timeout)) {
 153                 mod_timer(&tid_rx->session_timer, timeout);
 154                 return;
 155         }
 156
 157         ht_dbg(sta->sdata, "RX session timer expired on %pM tid %d\n",
 158                sta->sta.addr, tid);
 159
 160         set_bit(tid, sta->ampdu_mlme.tid_rx_timer_expired);
 161         wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);
 162 }
 163
 164 static void sta_rx_agg_reorder_timer_expired(struct timer_list *t)
 165 {
 166         struct tid_ampdu_rx *tid_rx = from_timer(tid_rx, t, reorder_timer);
 167
 168         rcu_read_lock();
 169         ieee80211_release_reorder_timeout(tid_rx->sta, tid_rx->tid);
 170         rcu_read_unlock();
 171 }
 172
 173 static void ieee80211_add_addbaext(struct ieee80211_sub_if_data *sdata,
 174                                    struct sk_buff *skb,
 175                                    const struct ieee80211_addba_ext_ie *req,
 176                                    u16 buf_size)
 177 {
 178         struct ieee80211_addba_ext_ie *resp;
 179         u8 *pos;
 180
 181         pos = skb_put_zero(skb, 2 + sizeof(struct ieee80211_addba_ext_ie));
 182         *pos++ = WLAN_EID_ADDBA_EXT;
 183         *pos++ = sizeof(struct ieee80211_addba_ext_ie);
 184         resp = (struct ieee80211_addba_ext_ie *)pos;
 185         resp->data = req->data & IEEE80211_ADDBA_EXT_NO_FRAG;
 186
 187         resp->data |= u8_encode_bits(buf_size >> IEEE80211_ADDBA_EXT_BUF_SIZE_SHIFT,
 188                                      IEEE80211_ADDBA_EXT_BUF_SIZE_MASK);
 189 }
 190
 191 static void ieee80211_send_addba_resp(struct sta_info *sta, u8 *da, u16 tid,
 192                                       u8 dialog_token, u16 status, u16 policy,
 193                                       u16 buf_size, u16 timeout,
 194                                       const struct ieee80211_addba_ext_ie *addbaext)
 195 {
 196         struct ieee80211_sub_if_data *sdata = sta->sdata;
 197         struct ieee80211_local *local = sdata->local;
 198         struct sk_buff *skb;
 199         struct ieee80211_mgmt *mgmt;
 200         bool amsdu = ieee80211_hw_check(&local->hw, SUPPORTS_AMSDU_IN_AMPDU);
 201         u16 capab;
 202
 203         skb = dev_alloc_skb(sizeof(*mgmt) +
 204                     2 + sizeof(struct ieee80211_addba_ext_ie) +
 205                     local->hw.extra_tx_headroom);
 206         if (!skb)
 207                 return;
 208
 209         skb_reserve(skb, local->hw.extra_tx_headroom);
 210         mgmt = skb_put_zero(skb, 24);
 211         memcpy(mgmt->da, da, ETH_ALEN);
 212         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 213         if (sdata->vif.type == NL80211_IFTYPE_AP ||
 214             sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
 215             sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 216                 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 217         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
 218                 memcpy(mgmt->bssid, sdata->vif.cfg.ap_addr, ETH_ALEN);
 219         else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
 220                 memcpy(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN);
 221
 222         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 223                                           IEEE80211_STYPE_ACTION);
 224
 225         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_resp));
 226         mgmt->u.action.category = WLAN_CATEGORY_BACK;
 227         mgmt->u.action.u.addba_resp.action_code = WLAN_ACTION_ADDBA_RESP;
 228         mgmt->u.action.u.addba_resp.dialog_token = dialog_token;
 229
 230         capab = u16_encode_bits(amsdu, IEEE80211_ADDBA_PARAM_AMSDU_MASK);
 231         capab |= u16_encode_bits(policy, IEEE80211_ADDBA_PARAM_POLICY_MASK);
 232         capab |= u16_encode_bits(tid, IEEE80211_ADDBA_PARAM_TID_MASK);
 233         capab |= u16_encode_bits(buf_size, IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK);
 234
 235         mgmt->u.action.u.addba_resp.capab = cpu_to_le16(capab);
 236         mgmt->u.action.u.addba_resp.timeout = cpu_to_le16(timeout);
 237         mgmt->u.action.u.addba_resp.status = cpu_to_le16(status);
 238
 239         if (sta->sta.deflink.he_cap.has_he && addbaext)
 240                 ieee80211_add_addbaext(sdata, skb, addbaext, buf_size);
 241
 242         ieee80211_tx_skb(sdata, skb);
 243 }
 244
 245 void __ieee80211_start_rx_ba_session(struct sta_info *sta,
 246                                      u8 dialog_token, u16 timeout,
 247                                      u16 start_seq_num, u16 ba_policy, u16 tid,
 248                                      u16 buf_size, bool tx, bool auto_seq,
 249                                      const struct ieee80211_addba_ext_ie *addbaext)
 250 {
 251         struct ieee80211_local *local = sta->sdata->local;
 252         struct tid_ampdu_rx *tid_agg_rx;
 253         struct ieee80211_ampdu_params params = {
 254                 .sta = &sta->sta,
 255                 .action = IEEE80211_AMPDU_RX_START,
 256                 .tid = tid,
 257                 .amsdu = false,
 258                 .timeout = timeout,
 259                 .ssn = start_seq_num,
 260         };
 261         int i, ret = -EOPNOTSUPP;
 262         u16 status = WLAN_STATUS_REQUEST_DECLINED;
 263         u16 max_buf_size;
 264
 265         lockdep_assert_wiphy(sta->local->hw.wiphy);
 266
 267         if (tid >= IEEE80211_FIRST_TSPEC_TSID) {
 268                 ht_dbg(sta->sdata,
 269                        "STA %pM requests BA session on unsupported tid %d\n",
 270                        sta->sta.addr, tid);
 271                 goto end;
 272         }
 273
 274         if (!sta->sta.deflink.ht_cap.ht_supported &&
 275             !sta->sta.deflink.he_cap.has_he) {
 276                 ht_dbg(sta->sdata,
 277                        "STA %pM erroneously requests BA session on tid %d w/o HT\n",
 278                        sta->sta.addr, tid);
 279                 /* send a response anyway, it's an error case if we get here */
 280                 goto end;
 281         }
 282
 283         if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
 284                 ht_dbg(sta->sdata,
 285                        "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
 286                        sta->sta.addr, tid);
 287                 goto end;
 288         }
 289
 290         if (sta->sta.deflink.eht_cap.has_eht)
 291                 max_buf_size = IEEE80211_MAX_AMPDU_BUF_EHT;
 292         else if (sta->sta.deflink.he_cap.has_he)
 293                 max_buf_size = IEEE80211_MAX_AMPDU_BUF_HE;
 294         else
 295                 max_buf_size = IEEE80211_MAX_AMPDU_BUF_HT;
 296
 297         /* sanity check for incoming parameters:
 298          * check if configuration can support the BA policy
 299          * and if buffer size does not exceeds max value */
 300         /* XXX: check own ht delayed BA capability?? */
 301         if (((ba_policy != 1) &&
 302              (!(sta->sta.deflink.ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA))) ||
 303             (buf_size > max_buf_size)) {
 304                 status = WLAN_STATUS_INVALID_QOS_PARAM;
 305                 ht_dbg_ratelimited(sta->sdata,
 306                                    "AddBA Req with bad params from %pM on tid %u. policy %d, buffer size %d\n",
 307                                    sta->sta.addr, tid, ba_policy, buf_size);
 308                 goto end;
 309         }
 310         /* determine default buffer size */
 311         if (buf_size == 0)
 312                 buf_size = max_buf_size;
 313
 314         /* make sure the size doesn't exceed the maximum supported by the hw */
 315         if (buf_size > sta->sta.max_rx_aggregation_subframes)
 316                 buf_size = sta->sta.max_rx_aggregation_subframes;
 317         params.buf_size = buf_size;
 318
 319         ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
 320                buf_size, sta->sta.addr);
 321
 322         if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) {
 323                 if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
 324                         struct tid_ampdu_rx *tid_rx;
 325
 326                         ht_dbg_ratelimited(sta->sdata,
 327                                            "updated AddBA Req from %pM on tid %u\n",
 328                                            sta->sta.addr, tid);
 329                         /* We have no API to update the timeout value in the
 330                          * driver so reject the timeout update if the timeout
 331                          * changed. If it did not change, i.e., no real update,
 332                          * just reply with success.
 333                          */
 334                         rcu_read_lock();
 335                         tid_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
 336                         if (tid_rx && tid_rx->timeout == timeout)
 337                                 status = WLAN_STATUS_SUCCESS;
 338                         else
 339                                 status = WLAN_STATUS_REQUEST_DECLINED;
 340                         rcu_read_unlock();
 341                         goto end;
 342                 }
 343
 344                 ht_dbg_ratelimited(sta->sdata,
 345                                    "unexpected AddBA Req from %pM on tid %u\n",
 346                                    sta->sta.addr, tid);
 347
 348                 /* delete existing Rx BA session on the same tid */
 349                 __ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
 350                                                WLAN_STATUS_UNSPECIFIED_QOS,
 351                                                false);
 352         }
 353
 354         if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
 355                 ret = drv_ampdu_action(local, sta->sdata, &params);
 356                 ht_dbg(sta->sdata,
 357                        "Rx A-MPDU request on %pM tid %d result %d\n",
 358                        sta->sta.addr, tid, ret);
 359                 if (!ret)
 360                         status = WLAN_STATUS_SUCCESS;
 361                 goto end;
 362         }
 363
 364         /* prepare A-MPDU MLME for Rx aggregation */
 365         tid_agg_rx = kzalloc(sizeof(*tid_agg_rx), GFP_KERNEL);
 366         if (!tid_agg_rx)
 367                 goto end;
 368
 369         spin_lock_init(&tid_agg_rx->reorder_lock);
 370
 371         /* rx timer */
 372         timer_setup(&tid_agg_rx->session_timer,
 373                     sta_rx_agg_session_timer_expired, TIMER_DEFERRABLE);
 374
 375         /* rx reorder timer */
 376         timer_setup(&tid_agg_rx->reorder_timer,
 377                     sta_rx_agg_reorder_timer_expired, 0);
 378
 379         /* prepare reordering buffer */
 380         tid_agg_rx->reorder_buf =
 381                 kcalloc(buf_size, sizeof(struct sk_buff_head), GFP_KERNEL);
 382         tid_agg_rx->reorder_time =
 383                 kcalloc(buf_size, sizeof(unsigned long), GFP_KERNEL);
 384         if (!tid_agg_rx->reorder_buf || !tid_agg_rx->reorder_time) {
 385                 kfree(tid_agg_rx->reorder_buf);
 386                 kfree(tid_agg_rx->reorder_time);
 387                 kfree(tid_agg_rx);
 388                 goto end;
 389         }
 390
 391         for (i = 0; i < buf_size; i++)
 392                 __skb_queue_head_init(&tid_agg_rx->reorder_buf[i]);
 393
 394         ret = drv_ampdu_action(local, sta->sdata, &params);
 395         ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
 396                sta->sta.addr, tid, ret);
 397         if (ret) {
 398                 kfree(tid_agg_rx->reorder_buf);
 399                 kfree(tid_agg_rx->reorder_time);
 400                 kfree(tid_agg_rx);
 401                 goto end;
 402         }
 403
 404         /* update data */
 405         tid_agg_rx->ssn = start_seq_num;
 406         tid_agg_rx->head_seq_num = start_seq_num;
 407         tid_agg_rx->buf_size = buf_size;
 408         tid_agg_rx->timeout = timeout;
 409         tid_agg_rx->stored_mpdu_num = 0;
 410         tid_agg_rx->auto_seq = auto_seq;
 411         tid_agg_rx->started = false;
 412         tid_agg_rx->reorder_buf_filtered = 0;
 413         tid_agg_rx->tid = tid;
 414         tid_agg_rx->sta = sta;
 415         status = WLAN_STATUS_SUCCESS;
 416
 417         /* activate it for RX */
 418         rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], tid_agg_rx);
 419
 420         if (timeout) {
 421                 mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(timeout));
 422                 tid_agg_rx->last_rx = jiffies;
 423         }
 424
 425 end:
 426         if (status == WLAN_STATUS_SUCCESS) {
 427                 __set_bit(tid, sta->ampdu_mlme.agg_session_valid);
 428                 __clear_bit(tid, sta->ampdu_mlme.unexpected_agg);
 429                 sta->ampdu_mlme.tid_rx_token[tid] = dialog_token;
 430         }
 431
 432         if (tx)
 433                 ieee80211_send_addba_resp(sta, sta->sta.addr, tid,
 434                                           dialog_token, status, 1, buf_size,
 435                                           timeout, addbaext);
 436 }
 437
 438 void ieee80211_process_addba_request(struct ieee80211_local *local,
 439                                      struct sta_info *sta,
 440                                      struct ieee80211_mgmt *mgmt,
 441                                      size_t len)
 442 {
 443         u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num;
 444         struct ieee802_11_elems *elems = NULL;
 445         u8 dialog_token;
 446         int ies_len;
 447
 448         /* extract session parameters from addba request frame */
 449         dialog_token = mgmt->u.action.u.addba_req.dialog_token;
 450         timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
 451         start_seq_num =
 452                 le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;
 453
 454         capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
 455         ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
 456         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 457         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 458
 459         ies_len = len - offsetof(struct ieee80211_mgmt,
 460                                  u.action.u.addba_req.variable);
 461         if (ies_len) {
 462                 elems = ieee802_11_parse_elems(mgmt->u.action.u.addba_req.variable,
 463                                                ies_len, true, NULL);
 464                 if (!elems || elems->parse_error)
 465                         goto free;
 466         }
 467
 468         if (sta->sta.deflink.eht_cap.has_eht && elems && elems->addba_ext_ie) {
 469                 u8 buf_size_1k = u8_get_bits(elems->addba_ext_ie->data,
 470                                              IEEE80211_ADDBA_EXT_BUF_SIZE_MASK);
 471
 472                 buf_size |= buf_size_1k << IEEE80211_ADDBA_EXT_BUF_SIZE_SHIFT;
 473         }
 474
 475         __ieee80211_start_rx_ba_session(sta, dialog_token, timeout,
 476                                         start_seq_num, ba_policy, tid,
 477                                         buf_size, true, false,
 478                                         elems ? elems->addba_ext_ie : NULL);
 479 free:
 480         kfree(elems);
 481 }
 482
 483 void ieee80211_manage_rx_ba_offl(struct ieee80211_vif *vif,
 484                                  const u8 *addr, unsigned int tid)
 485 {
 486         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 487         struct sta_info *sta;
 488
 489         rcu_read_lock();
 490         sta = sta_info_get_bss(sdata, addr);
 491         if (!sta)
 492                 goto unlock;
 493
 494         set_bit(tid, sta->ampdu_mlme.tid_rx_manage_offl);
 495         wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);
 496  unlock:
 497         rcu_read_unlock();
 498 }
 499 EXPORT_SYMBOL(ieee80211_manage_rx_ba_offl);
 500
 501 void ieee80211_rx_ba_timer_expired(struct ieee80211_vif *vif,
 502                                    const u8 *addr, unsigned int tid)
 503 {
 504         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 505         struct sta_info *sta;
 506
 507         rcu_read_lock();
 508         sta = sta_info_get_bss(sdata, addr);
 509         if (!sta)
 510                 goto unlock;
 511
 512         set_bit(tid, sta->ampdu_mlme.tid_rx_timer_expired);
 513         wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);
 514
 515  unlock:
 516         rcu_read_unlock();
 517 }
 518 EXPORT_SYMBOL(ieee80211_rx_ba_timer_expired);