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) 2018-2026 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
ieee80211_free_tid_rx(struct rcu_head * h)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[i].buf);
53 kfree(tid_rx);
54 }
55
__ieee80211_stop_rx_ba_session(struct sta_info * sta,u16 tid,u16 initiator,u16 reason,bool tx)56 void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
57 u16 initiator, u16 reason, bool tx)
58 {
59 struct ieee80211_local *local = sta->local;
60 struct tid_ampdu_rx *tid_rx;
61 struct ieee80211_ampdu_params params = {
62 .sta = &sta->sta,
63 .action = IEEE80211_AMPDU_RX_STOP,
64 .tid = tid,
65 .amsdu = false,
66 .timeout = 0,
67 .ssn = 0,
68 };
69
70 lockdep_assert_wiphy(sta->local->hw.wiphy);
71
72 tid_rx = rcu_dereference_protected(sta->ampdu_mlme.tid_rx[tid],
73 lockdep_is_held(&sta->local->hw.wiphy->mtx));
74
75 if (!test_bit(tid, sta->ampdu_mlme.agg_session_valid))
76 return;
77
78 RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
79 __clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
80
81 ht_dbg(sta->sdata,
82 "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
83 sta->sta.addr, tid,
84 initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
85 (int)reason);
86
87 if (drv_ampdu_action(local, sta->sdata, ¶ms))
88 sdata_info(sta->sdata,
89 "HW problem - can not stop rx aggregation for %pM tid %d\n",
90 sta->sta.addr, tid);
91
92 /* check if this is a self generated aggregation halt */
93 if (initiator == WLAN_BACK_RECIPIENT && tx)
94 ieee80211_send_delba(sta->sdata, sta->sta.addr,
95 tid, WLAN_BACK_RECIPIENT, reason,
96 ieee80211_s1g_use_ndp_ba(sta->sdata, sta));
97
98 /*
99 * return here in case tid_rx is not assigned - which will happen if
100 * IEEE80211_HW_SUPPORTS_REORDERING_BUFFER is set.
101 */
102 if (!tid_rx)
103 return;
104
105 timer_shutdown_sync(&tid_rx->session_timer);
106
107 /* make sure ieee80211_sta_reorder_release() doesn't re-arm the timer */
108 spin_lock_bh(&tid_rx->reorder_lock);
109 tid_rx->removed = true;
110 spin_unlock_bh(&tid_rx->reorder_lock);
111 timer_delete_sync(&tid_rx->reorder_timer);
112
113 call_rcu(&tid_rx->rcu_head, ieee80211_free_tid_rx);
114 }
115
ieee80211_stop_rx_ba_session(struct ieee80211_vif * vif,u16 ba_rx_bitmap,const u8 * addr)116 void ieee80211_stop_rx_ba_session(struct ieee80211_vif *vif, u16 ba_rx_bitmap,
117 const u8 *addr)
118 {
119 struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
120 struct sta_info *sta;
121 int i;
122
123 rcu_read_lock();
124 sta = sta_info_get_bss(sdata, addr);
125 if (!sta) {
126 rcu_read_unlock();
127 return;
128 }
129
130 for (i = 0; i < IEEE80211_NUM_TIDS; i++)
131 if (ba_rx_bitmap & BIT(i))
132 set_bit(i, sta->ampdu_mlme.tid_rx_stop_requested);
133
134 wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);
135 rcu_read_unlock();
136 }
137 EXPORT_SYMBOL(ieee80211_stop_rx_ba_session);
138
139 /*
140 * After accepting the AddBA Request we activated a timer,
141 * resetting it after each frame that arrives from the originator.
142 */
sta_rx_agg_session_timer_expired(struct timer_list * t)143 static void sta_rx_agg_session_timer_expired(struct timer_list *t)
144 {
145 struct tid_ampdu_rx *tid_rx = timer_container_of(tid_rx, t,
146 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
sta_rx_agg_reorder_timer_expired(struct timer_list * t)164 static void sta_rx_agg_reorder_timer_expired(struct timer_list *t)
165 {
166 struct tid_ampdu_rx *tid_rx = timer_container_of(tid_rx, t,
167 reorder_timer);
168
169 rcu_read_lock();
170 ieee80211_release_reorder_timeout(tid_rx->sta, tid_rx->tid);
171 rcu_read_unlock();
172 }
173
ieee80211_add_addbaext(struct sk_buff * skb,const u8 req_addba_ext_data,u16 buf_size)174 void ieee80211_add_addbaext(struct sk_buff *skb,
175 const u8 req_addba_ext_data,
176 u16 buf_size)
177 {
178 struct ieee80211_addba_ext_ie *addba_ext;
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 addba_ext = (struct ieee80211_addba_ext_ie *)pos;
185
186 addba_ext->data = IEEE80211_ADDBA_EXT_NO_FRAG;
187 if (req_addba_ext_data)
188 addba_ext->data &= req_addba_ext_data;
189
190 addba_ext->data |=
191 u8_encode_bits(buf_size >> IEEE80211_ADDBA_EXT_BUF_SIZE_SHIFT,
192 IEEE80211_ADDBA_EXT_BUF_SIZE_MASK);
193 }
194
ieee80211_retrieve_addba_ext_data(struct sta_info * sta,const void * elem_data,ssize_t elem_len,u16 * buf_size)195 u8 ieee80211_retrieve_addba_ext_data(struct sta_info *sta,
196 const void *elem_data, ssize_t elem_len,
197 u16 *buf_size)
198 {
199 struct ieee802_11_elems *elems;
200 u8 buf_size_1k, data = 0;
201
202 if (!sta->sta.deflink.he_cap.has_he)
203 return 0;
204
205 if (elem_len <= 0)
206 return 0;
207
208 elems = ieee802_11_parse_elems(elem_data, elem_len,
209 IEEE80211_FTYPE_MGMT |
210 IEEE80211_STYPE_ACTION,
211 NULL);
212
213 if (!elems || elems->parse_error || !elems->addba_ext_ie)
214 goto free;
215
216 data = elems->addba_ext_ie->data;
217
218 if (buf_size &&
219 (sta->sta.valid_links || sta->sta.deflink.eht_cap.has_eht)) {
220 buf_size_1k = u8_get_bits(elems->addba_ext_ie->data,
221 IEEE80211_ADDBA_EXT_BUF_SIZE_MASK);
222 *buf_size |= (u16)buf_size_1k <<
223 IEEE80211_ADDBA_EXT_BUF_SIZE_SHIFT;
224 }
225
226 free:
227 kfree(elems);
228
229 return data;
230 }
231
ieee80211_send_addba_resp(struct sta_info * sta,u8 * da,u16 tid,u8 dialog_token,u16 status,u16 policy,u16 buf_size,u16 timeout,const u8 req_addba_ext_data)232 static void ieee80211_send_addba_resp(struct sta_info *sta, u8 *da, u16 tid,
233 u8 dialog_token, u16 status, u16 policy,
234 u16 buf_size, u16 timeout,
235 const u8 req_addba_ext_data)
236 {
237 struct ieee80211_sub_if_data *sdata = sta->sdata;
238 struct ieee80211_local *local = sdata->local;
239 struct sk_buff *skb;
240 struct ieee80211_mgmt *mgmt;
241 bool amsdu = ieee80211_hw_check(&local->hw, SUPPORTS_AMSDU_IN_AMPDU);
242 bool use_ndp = ieee80211_s1g_use_ndp_ba(sdata, sta);
243 u16 capab;
244
245 skb = dev_alloc_skb(sizeof(*mgmt) +
246 2 + sizeof(struct ieee80211_addba_ext_ie) +
247 local->hw.extra_tx_headroom);
248 if (!skb)
249 return;
250
251 skb_reserve(skb, local->hw.extra_tx_headroom);
252 mgmt = ieee80211_mgmt_ba(skb, da, sdata);
253
254 skb_put(skb, 2 + sizeof(mgmt->u.action.addba_resp));
255 mgmt->u.action.category = WLAN_CATEGORY_BACK;
256 mgmt->u.action.action_code = use_ndp ?
257 WLAN_ACTION_NDP_ADDBA_RESP : WLAN_ACTION_ADDBA_RESP;
258
259 mgmt->u.action.addba_resp.dialog_token = dialog_token;
260
261 capab = u16_encode_bits(amsdu, IEEE80211_ADDBA_PARAM_AMSDU_MASK);
262 capab |= u16_encode_bits(policy, IEEE80211_ADDBA_PARAM_POLICY_MASK);
263 capab |= u16_encode_bits(tid, IEEE80211_ADDBA_PARAM_TID_MASK);
264 capab |= u16_encode_bits(buf_size, IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK);
265
266 mgmt->u.action.addba_resp.capab = cpu_to_le16(capab);
267 mgmt->u.action.addba_resp.timeout = cpu_to_le16(timeout);
268 mgmt->u.action.addba_resp.status = cpu_to_le16(status);
269
270 if (sta->sta.valid_links || sta->sta.deflink.he_cap.has_he)
271 ieee80211_add_addbaext(skb, req_addba_ext_data, buf_size);
272
273 ieee80211_tx_skb(sdata, skb);
274 }
275
__ieee80211_start_rx_ba_session(struct sta_info * sta,u8 dialog_token,u16 timeout,u16 start_seq_num,u16 ba_policy,u16 tid,u16 buf_size,bool tx,bool auto_seq,bool req_ndp,const u8 addba_ext_data)276 void __ieee80211_start_rx_ba_session(struct sta_info *sta,
277 u8 dialog_token, u16 timeout,
278 u16 start_seq_num, u16 ba_policy, u16 tid,
279 u16 buf_size, bool tx, bool auto_seq,
280 bool req_ndp,
281 const u8 addba_ext_data)
282 {
283 struct ieee80211_local *local = sta->sdata->local;
284 struct tid_ampdu_rx *tid_agg_rx;
285 struct ieee80211_ampdu_params params = {
286 .sta = &sta->sta,
287 .action = IEEE80211_AMPDU_RX_START,
288 .tid = tid,
289 .amsdu = false,
290 .timeout = timeout,
291 .ssn = start_seq_num,
292 };
293 int i, ret = -EOPNOTSUPP;
294 u16 status = WLAN_STATUS_REQUEST_DECLINED;
295 u16 max_buf_size;
296
297 lockdep_assert_wiphy(sta->local->hw.wiphy);
298
299 if (tid >= IEEE80211_FIRST_TSPEC_TSID) {
300 ht_dbg(sta->sdata,
301 "STA %pM requests BA session on unsupported tid %d\n",
302 sta->sta.addr, tid);
303 goto end;
304 }
305
306 if (tx && ieee80211_s1g_use_ndp_ba(sta->sdata, sta) && !req_ndp) {
307 /*
308 * According to IEEE 802.11-2024: Inform S1G originator
309 * ADDBA rejected as NDP BlockAck is preferred
310 */
311 status = WLAN_STATUS_REJECTED_NDP_BLOCK_ACK_SUGGESTED;
312 ht_dbg(sta->sdata,
313 "Rejecting AddBA Req from %pM tid %u - require NDP BlockAck\n",
314 sta->sta.addr, tid);
315 goto end;
316 }
317
318 if (!sta->sta.valid_links &&
319 !sta->sta.deflink.ht_cap.ht_supported &&
320 !sta->sta.deflink.he_cap.has_he &&
321 !sta->sta.deflink.s1g_cap.s1g) {
322 ht_dbg(sta->sdata,
323 "STA %pM erroneously requests BA session on tid %d w/o HT\n",
324 sta->sta.addr, tid);
325 /* send a response anyway, it's an error case if we get here */
326 goto end;
327 }
328
329 if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
330 ht_dbg(sta->sdata,
331 "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
332 sta->sta.addr, tid);
333 goto end;
334 }
335
336 if (sta->sta.valid_links || sta->sta.deflink.eht_cap.has_eht)
337 max_buf_size = IEEE80211_MAX_AMPDU_BUF_EHT;
338 else if (sta->sta.deflink.he_cap.has_he)
339 max_buf_size = IEEE80211_MAX_AMPDU_BUF_HE;
340 else
341 max_buf_size = IEEE80211_MAX_AMPDU_BUF_HT;
342
343 /* sanity check for incoming parameters:
344 * check if configuration can support the BA policy
345 * and if buffer size does not exceeds max value */
346 /* XXX: check own ht delayed BA capability?? */
347 if (((ba_policy != 1) &&
348 (sta->sta.valid_links ||
349 !(sta->sta.deflink.ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA) ||
350 !(sta->sta.deflink.s1g_cap.cap[3] & S1G_CAP3_HT_DELAYED_BA))) ||
351 (buf_size > max_buf_size)) {
352 status = WLAN_STATUS_INVALID_QOS_PARAM;
353 ht_dbg_ratelimited(sta->sdata,
354 "AddBA Req with bad params from %pM on tid %u. policy %d, buffer size %d\n",
355 sta->sta.addr, tid, ba_policy, buf_size);
356 goto end;
357 }
358 /* determine default buffer size */
359 if (buf_size == 0)
360 buf_size = max_buf_size;
361
362 /* make sure the size doesn't exceed the maximum supported by the hw */
363 if (buf_size > sta->sta.max_rx_aggregation_subframes)
364 buf_size = sta->sta.max_rx_aggregation_subframes;
365 params.buf_size = buf_size;
366
367 ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
368 buf_size, sta->sta.addr);
369
370 if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) {
371 if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
372 struct tid_ampdu_rx *tid_rx;
373
374 ht_dbg_ratelimited(sta->sdata,
375 "updated AddBA Req from %pM on tid %u\n",
376 sta->sta.addr, tid);
377 /* We have no API to update the timeout value in the
378 * driver so reject the timeout update if the timeout
379 * changed. If it did not change, i.e., no real update,
380 * just reply with success.
381 */
382 rcu_read_lock();
383 tid_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
384 if (tid_rx && tid_rx->timeout == timeout)
385 status = WLAN_STATUS_SUCCESS;
386 else
387 status = WLAN_STATUS_REQUEST_DECLINED;
388 rcu_read_unlock();
389 goto end;
390 }
391
392 ht_dbg_ratelimited(sta->sdata,
393 "unexpected AddBA Req from %pM on tid %u\n",
394 sta->sta.addr, tid);
395
396 /* delete existing Rx BA session on the same tid */
397 __ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
398 WLAN_STATUS_UNSPECIFIED_QOS,
399 false);
400 }
401
402 if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
403 ret = drv_ampdu_action(local, sta->sdata, ¶ms);
404 ht_dbg(sta->sdata,
405 "Rx A-MPDU request on %pM tid %d result %d\n",
406 sta->sta.addr, tid, ret);
407 if (!ret)
408 status = WLAN_STATUS_SUCCESS;
409 goto end;
410 }
411
412 /* prepare A-MPDU MLME for Rx aggregation */
413 tid_agg_rx = kzalloc_flex(*tid_agg_rx, reorder, buf_size);
414 if (!tid_agg_rx)
415 goto end;
416
417 spin_lock_init(&tid_agg_rx->reorder_lock);
418
419 /* rx timer */
420 timer_setup(&tid_agg_rx->session_timer,
421 sta_rx_agg_session_timer_expired, TIMER_DEFERRABLE);
422
423 /* rx reorder timer */
424 timer_setup(&tid_agg_rx->reorder_timer,
425 sta_rx_agg_reorder_timer_expired, 0);
426
427 for (i = 0; i < buf_size; i++)
428 __skb_queue_head_init(&tid_agg_rx->reorder[i].buf);
429
430 ret = drv_ampdu_action(local, sta->sdata, ¶ms);
431 ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
432 sta->sta.addr, tid, ret);
433 if (ret) {
434 kfree(tid_agg_rx);
435 goto end;
436 }
437
438 /* update data */
439 tid_agg_rx->ssn = start_seq_num;
440 tid_agg_rx->head_seq_num = start_seq_num;
441 tid_agg_rx->buf_size = buf_size;
442 tid_agg_rx->timeout = timeout;
443 tid_agg_rx->stored_mpdu_num = 0;
444 tid_agg_rx->auto_seq = auto_seq;
445 tid_agg_rx->started = false;
446 tid_agg_rx->reorder_buf_filtered = 0;
447 tid_agg_rx->tid = tid;
448 tid_agg_rx->sta = sta;
449 status = WLAN_STATUS_SUCCESS;
450
451 /* activate it for RX */
452 rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], tid_agg_rx);
453
454 if (timeout) {
455 mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(timeout));
456 tid_agg_rx->last_rx = jiffies;
457 }
458
459 end:
460 if (status == WLAN_STATUS_SUCCESS) {
461 __set_bit(tid, sta->ampdu_mlme.agg_session_valid);
462 __clear_bit(tid, sta->ampdu_mlme.unexpected_agg);
463 sta->ampdu_mlme.tid_rx_token[tid] = dialog_token;
464 }
465
466 if (tx)
467 ieee80211_send_addba_resp(sta, sta->sta.addr, tid,
468 dialog_token, status, 1, buf_size,
469 timeout, addba_ext_data);
470 }
471
ieee80211_process_addba_request(struct ieee80211_local * local,struct sta_info * sta,struct ieee80211_mgmt * mgmt,size_t len)472 void ieee80211_process_addba_request(struct ieee80211_local *local,
473 struct sta_info *sta,
474 struct ieee80211_mgmt *mgmt,
475 size_t len)
476 {
477 bool req_ndp = mgmt->u.action.action_code == WLAN_ACTION_NDP_ADDBA_REQ;
478 u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num;
479 u8 dialog_token, addba_ext_data;
480
481 /* extract session parameters from addba request frame */
482 dialog_token = mgmt->u.action.addba_req.dialog_token;
483 timeout = le16_to_cpu(mgmt->u.action.addba_req.timeout);
484 start_seq_num =
485 le16_to_cpu(mgmt->u.action.addba_req.start_seq_num) >> 4;
486
487 capab = le16_to_cpu(mgmt->u.action.addba_req.capab);
488 ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
489 tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
490 buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
491
492 addba_ext_data =
493 ieee80211_retrieve_addba_ext_data(sta,
494 mgmt->u.action.addba_req.variable,
495 len -
496 offsetof(typeof(*mgmt),
497 u.action.addba_req.variable),
498 &buf_size);
499
500 __ieee80211_start_rx_ba_session(sta, dialog_token, timeout,
501 start_seq_num, ba_policy, tid,
502 buf_size, true, false,
503 req_ndp, addba_ext_data);
504 }
505
ieee80211_manage_rx_ba_offl(struct ieee80211_vif * vif,const u8 * addr,unsigned int tid)506 void ieee80211_manage_rx_ba_offl(struct ieee80211_vif *vif,
507 const u8 *addr, unsigned int tid)
508 {
509 struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
510 struct sta_info *sta;
511
512 rcu_read_lock();
513 sta = sta_info_get_bss(sdata, addr);
514 if (!sta)
515 goto unlock;
516
517 set_bit(tid, sta->ampdu_mlme.tid_rx_manage_offl);
518 wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);
519 unlock:
520 rcu_read_unlock();
521 }
522 EXPORT_SYMBOL(ieee80211_manage_rx_ba_offl);
523
ieee80211_rx_ba_timer_expired(struct ieee80211_vif * vif,const u8 * addr,unsigned int tid)524 void ieee80211_rx_ba_timer_expired(struct ieee80211_vif *vif,
525 const u8 *addr, unsigned int tid)
526 {
527 struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
528 struct sta_info *sta;
529
530 rcu_read_lock();
531 sta = sta_info_get_bss(sdata, addr);
532 if (!sta)
533 goto unlock;
534
535 set_bit(tid, sta->ampdu_mlme.tid_rx_timer_expired);
536 wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);
537
538 unlock:
539 rcu_read_unlock();
540 }
541 EXPORT_SYMBOL(ieee80211_rx_ba_timer_expired);
542