xref: /linux/net/mac80211/sta_info.c (revision 1ccd4b7bfdcfcc8cc7ffc4a9c11d3ac5b6da8ca0)
1 /*
2  * Copyright 2002-2005, Instant802 Networks, Inc.
3  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  */
9 
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/netdevice.h>
13 #include <linux/types.h>
14 #include <linux/slab.h>
15 #include <linux/skbuff.h>
16 #include <linux/if_arp.h>
17 #include <linux/timer.h>
18 #include <linux/rtnetlink.h>
19 
20 #include <net/mac80211.h>
21 #include "ieee80211_i.h"
22 #include "driver-ops.h"
23 #include "rate.h"
24 #include "sta_info.h"
25 #include "debugfs_sta.h"
26 #include "mesh.h"
27 
28 /**
29  * DOC: STA information lifetime rules
30  *
31  * STA info structures (&struct sta_info) are managed in a hash table
32  * for faster lookup and a list for iteration. They are managed using
33  * RCU, i.e. access to the list and hash table is protected by RCU.
34  *
35  * Upon allocating a STA info structure with sta_info_alloc(), the caller
36  * owns that structure. It must then insert it into the hash table using
37  * either sta_info_insert() or sta_info_insert_rcu(); only in the latter
38  * case (which acquires an rcu read section but must not be called from
39  * within one) will the pointer still be valid after the call. Note that
40  * the caller may not do much with the STA info before inserting it, in
41  * particular, it may not start any mesh peer link management or add
42  * encryption keys.
43  *
44  * When the insertion fails (sta_info_insert()) returns non-zero), the
45  * structure will have been freed by sta_info_insert()!
46  *
47  * Station entries are added by mac80211 when you establish a link with a
48  * peer. This means different things for the different type of interfaces
49  * we support. For a regular station this mean we add the AP sta when we
50  * receive an association response from the AP. For IBSS this occurs when
51  * get to know about a peer on the same IBSS. For WDS we add the sta for
52  * the peer immediately upon device open. When using AP mode we add stations
53  * for each respective station upon request from userspace through nl80211.
54  *
55  * In order to remove a STA info structure, various sta_info_destroy_*()
56  * calls are available.
57  *
58  * There is no concept of ownership on a STA entry, each structure is
59  * owned by the global hash table/list until it is removed. All users of
60  * the structure need to be RCU protected so that the structure won't be
61  * freed before they are done using it.
62  */
63 
64 /* Caller must hold local->sta_lock */
65 static int sta_info_hash_del(struct ieee80211_local *local,
66 			     struct sta_info *sta)
67 {
68 	struct sta_info *s;
69 
70 	s = rcu_dereference_protected(local->sta_hash[STA_HASH(sta->sta.addr)],
71 				      lockdep_is_held(&local->sta_lock));
72 	if (!s)
73 		return -ENOENT;
74 	if (s == sta) {
75 		rcu_assign_pointer(local->sta_hash[STA_HASH(sta->sta.addr)],
76 				   s->hnext);
77 		return 0;
78 	}
79 
80 	while (rcu_access_pointer(s->hnext) &&
81 	       rcu_access_pointer(s->hnext) != sta)
82 		s = rcu_dereference_protected(s->hnext,
83 					lockdep_is_held(&local->sta_lock));
84 	if (rcu_access_pointer(s->hnext)) {
85 		rcu_assign_pointer(s->hnext, sta->hnext);
86 		return 0;
87 	}
88 
89 	return -ENOENT;
90 }
91 
92 /* protected by RCU */
93 struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
94 			      const u8 *addr)
95 {
96 	struct ieee80211_local *local = sdata->local;
97 	struct sta_info *sta;
98 
99 	sta = rcu_dereference_check(local->sta_hash[STA_HASH(addr)],
100 				    lockdep_is_held(&local->sta_lock) ||
101 				    lockdep_is_held(&local->sta_mtx));
102 	while (sta) {
103 		if (sta->sdata == sdata &&
104 		    memcmp(sta->sta.addr, addr, ETH_ALEN) == 0)
105 			break;
106 		sta = rcu_dereference_check(sta->hnext,
107 					    lockdep_is_held(&local->sta_lock) ||
108 					    lockdep_is_held(&local->sta_mtx));
109 	}
110 	return sta;
111 }
112 
113 /*
114  * Get sta info either from the specified interface
115  * or from one of its vlans
116  */
117 struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
118 				  const u8 *addr)
119 {
120 	struct ieee80211_local *local = sdata->local;
121 	struct sta_info *sta;
122 
123 	sta = rcu_dereference_check(local->sta_hash[STA_HASH(addr)],
124 				    lockdep_is_held(&local->sta_lock) ||
125 				    lockdep_is_held(&local->sta_mtx));
126 	while (sta) {
127 		if ((sta->sdata == sdata ||
128 		     (sta->sdata->bss && sta->sdata->bss == sdata->bss)) &&
129 		    memcmp(sta->sta.addr, addr, ETH_ALEN) == 0)
130 			break;
131 		sta = rcu_dereference_check(sta->hnext,
132 					    lockdep_is_held(&local->sta_lock) ||
133 					    lockdep_is_held(&local->sta_mtx));
134 	}
135 	return sta;
136 }
137 
138 struct sta_info *sta_info_get_by_idx(struct ieee80211_sub_if_data *sdata,
139 				     int idx)
140 {
141 	struct ieee80211_local *local = sdata->local;
142 	struct sta_info *sta;
143 	int i = 0;
144 
145 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
146 		if (sdata != sta->sdata)
147 			continue;
148 		if (i < idx) {
149 			++i;
150 			continue;
151 		}
152 		return sta;
153 	}
154 
155 	return NULL;
156 }
157 
158 /**
159  * __sta_info_free - internal STA free helper
160  *
161  * @local: pointer to the global information
162  * @sta: STA info to free
163  *
164  * This function must undo everything done by sta_info_alloc()
165  * that may happen before sta_info_insert().
166  */
167 static void __sta_info_free(struct ieee80211_local *local,
168 			    struct sta_info *sta)
169 {
170 	if (sta->rate_ctrl) {
171 		rate_control_free_sta(sta);
172 		rate_control_put(sta->rate_ctrl);
173 	}
174 
175 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
176 	wiphy_debug(local->hw.wiphy, "Destroyed STA %pM\n", sta->sta.addr);
177 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
178 
179 	kfree(sta);
180 }
181 
182 /* Caller must hold local->sta_lock */
183 static void sta_info_hash_add(struct ieee80211_local *local,
184 			      struct sta_info *sta)
185 {
186 	sta->hnext = local->sta_hash[STA_HASH(sta->sta.addr)];
187 	rcu_assign_pointer(local->sta_hash[STA_HASH(sta->sta.addr)], sta);
188 }
189 
190 static void sta_unblock(struct work_struct *wk)
191 {
192 	struct sta_info *sta;
193 
194 	sta = container_of(wk, struct sta_info, drv_unblock_wk);
195 
196 	if (sta->dead)
197 		return;
198 
199 	if (!test_sta_flags(sta, WLAN_STA_PS_STA))
200 		ieee80211_sta_ps_deliver_wakeup(sta);
201 	else if (test_and_clear_sta_flags(sta, WLAN_STA_PSPOLL)) {
202 		clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
203 		ieee80211_sta_ps_deliver_poll_response(sta);
204 	} else
205 		clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
206 }
207 
208 static int sta_prepare_rate_control(struct ieee80211_local *local,
209 				    struct sta_info *sta, gfp_t gfp)
210 {
211 	if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
212 		return 0;
213 
214 	sta->rate_ctrl = rate_control_get(local->rate_ctrl);
215 	sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
216 						     &sta->sta, gfp);
217 	if (!sta->rate_ctrl_priv) {
218 		rate_control_put(sta->rate_ctrl);
219 		return -ENOMEM;
220 	}
221 
222 	return 0;
223 }
224 
225 struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
226 				u8 *addr, gfp_t gfp)
227 {
228 	struct ieee80211_local *local = sdata->local;
229 	struct sta_info *sta;
230 	struct timespec uptime;
231 	int i;
232 
233 	sta = kzalloc(sizeof(*sta) + local->hw.sta_data_size, gfp);
234 	if (!sta)
235 		return NULL;
236 
237 	spin_lock_init(&sta->lock);
238 	spin_lock_init(&sta->flaglock);
239 	INIT_WORK(&sta->drv_unblock_wk, sta_unblock);
240 	INIT_WORK(&sta->ampdu_mlme.work, ieee80211_ba_session_work);
241 	mutex_init(&sta->ampdu_mlme.mtx);
242 
243 	memcpy(sta->sta.addr, addr, ETH_ALEN);
244 	sta->local = local;
245 	sta->sdata = sdata;
246 	sta->last_rx = jiffies;
247 
248 	do_posix_clock_monotonic_gettime(&uptime);
249 	sta->last_connected = uptime.tv_sec;
250 	ewma_init(&sta->avg_signal, 1024, 8);
251 
252 	if (sta_prepare_rate_control(local, sta, gfp)) {
253 		kfree(sta);
254 		return NULL;
255 	}
256 
257 	for (i = 0; i < STA_TID_NUM; i++) {
258 		/*
259 		 * timer_to_tid must be initialized with identity mapping
260 		 * to enable session_timer's data differentiation. See
261 		 * sta_rx_agg_session_timer_expired for usage.
262 		 */
263 		sta->timer_to_tid[i] = i;
264 	}
265 	skb_queue_head_init(&sta->ps_tx_buf);
266 	skb_queue_head_init(&sta->tx_filtered);
267 
268 	for (i = 0; i < NUM_RX_DATA_QUEUES; i++)
269 		sta->last_seq_ctrl[i] = cpu_to_le16(USHRT_MAX);
270 
271 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
272 	wiphy_debug(local->hw.wiphy, "Allocated STA %pM\n", sta->sta.addr);
273 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
274 
275 #ifdef CONFIG_MAC80211_MESH
276 	sta->plink_state = NL80211_PLINK_LISTEN;
277 	init_timer(&sta->plink_timer);
278 #endif
279 
280 	return sta;
281 }
282 
283 static int sta_info_finish_insert(struct sta_info *sta, bool async)
284 {
285 	struct ieee80211_local *local = sta->local;
286 	struct ieee80211_sub_if_data *sdata = sta->sdata;
287 	struct station_info sinfo;
288 	unsigned long flags;
289 	int err = 0;
290 
291 	lockdep_assert_held(&local->sta_mtx);
292 
293 	/* notify driver */
294 	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
295 		sdata = container_of(sdata->bss,
296 				     struct ieee80211_sub_if_data,
297 				     u.ap);
298 	err = drv_sta_add(local, sdata, &sta->sta);
299 	if (err) {
300 		if (!async)
301 			return err;
302 		printk(KERN_DEBUG "%s: failed to add IBSS STA %pM to driver (%d)"
303 				  " - keeping it anyway.\n",
304 		       sdata->name, sta->sta.addr, err);
305 	} else {
306 		sta->uploaded = true;
307 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
308 		if (async)
309 			wiphy_debug(local->hw.wiphy,
310 				    "Finished adding IBSS STA %pM\n",
311 				    sta->sta.addr);
312 #endif
313 	}
314 
315 	sdata = sta->sdata;
316 
317 	if (!async) {
318 		local->num_sta++;
319 		local->sta_generation++;
320 		smp_mb();
321 
322 		/* make the station visible */
323 		spin_lock_irqsave(&local->sta_lock, flags);
324 		sta_info_hash_add(local, sta);
325 		spin_unlock_irqrestore(&local->sta_lock, flags);
326 	}
327 
328 	list_add(&sta->list, &local->sta_list);
329 
330 	ieee80211_sta_debugfs_add(sta);
331 	rate_control_add_sta_debugfs(sta);
332 
333 	sinfo.filled = 0;
334 	sinfo.generation = local->sta_generation;
335 	cfg80211_new_sta(sdata->dev, sta->sta.addr, &sinfo, GFP_KERNEL);
336 
337 
338 	return 0;
339 }
340 
341 static void sta_info_finish_pending(struct ieee80211_local *local)
342 {
343 	struct sta_info *sta;
344 	unsigned long flags;
345 
346 	spin_lock_irqsave(&local->sta_lock, flags);
347 	while (!list_empty(&local->sta_pending_list)) {
348 		sta = list_first_entry(&local->sta_pending_list,
349 				       struct sta_info, list);
350 		list_del(&sta->list);
351 		spin_unlock_irqrestore(&local->sta_lock, flags);
352 
353 		sta_info_finish_insert(sta, true);
354 
355 		spin_lock_irqsave(&local->sta_lock, flags);
356 	}
357 	spin_unlock_irqrestore(&local->sta_lock, flags);
358 }
359 
360 static void sta_info_finish_work(struct work_struct *work)
361 {
362 	struct ieee80211_local *local =
363 		container_of(work, struct ieee80211_local, sta_finish_work);
364 
365 	mutex_lock(&local->sta_mtx);
366 	sta_info_finish_pending(local);
367 	mutex_unlock(&local->sta_mtx);
368 }
369 
370 int sta_info_insert_rcu(struct sta_info *sta) __acquires(RCU)
371 {
372 	struct ieee80211_local *local = sta->local;
373 	struct ieee80211_sub_if_data *sdata = sta->sdata;
374 	unsigned long flags;
375 	int err = 0;
376 
377 	/*
378 	 * Can't be a WARN_ON because it can be triggered through a race:
379 	 * something inserts a STA (on one CPU) without holding the RTNL
380 	 * and another CPU turns off the net device.
381 	 */
382 	if (unlikely(!ieee80211_sdata_running(sdata))) {
383 		err = -ENETDOWN;
384 		rcu_read_lock();
385 		goto out_free;
386 	}
387 
388 	if (WARN_ON(compare_ether_addr(sta->sta.addr, sdata->vif.addr) == 0 ||
389 		    is_multicast_ether_addr(sta->sta.addr))) {
390 		err = -EINVAL;
391 		rcu_read_lock();
392 		goto out_free;
393 	}
394 
395 	/*
396 	 * In ad-hoc mode, we sometimes need to insert stations
397 	 * from tasklet context from the RX path. To avoid races,
398 	 * always do so in that case -- see the comment below.
399 	 */
400 	if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
401 		spin_lock_irqsave(&local->sta_lock, flags);
402 		/* check if STA exists already */
403 		if (sta_info_get_bss(sdata, sta->sta.addr)) {
404 			spin_unlock_irqrestore(&local->sta_lock, flags);
405 			rcu_read_lock();
406 			err = -EEXIST;
407 			goto out_free;
408 		}
409 
410 		local->num_sta++;
411 		local->sta_generation++;
412 		smp_mb();
413 		sta_info_hash_add(local, sta);
414 
415 		list_add_tail(&sta->list, &local->sta_pending_list);
416 
417 		rcu_read_lock();
418 		spin_unlock_irqrestore(&local->sta_lock, flags);
419 
420 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
421 		wiphy_debug(local->hw.wiphy, "Added IBSS STA %pM\n",
422 			    sta->sta.addr);
423 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
424 
425 		ieee80211_queue_work(&local->hw, &local->sta_finish_work);
426 
427 		return 0;
428 	}
429 
430 	/*
431 	 * On first glance, this will look racy, because the code
432 	 * below this point, which inserts a station with sleeping,
433 	 * unlocks the sta_lock between checking existence in the
434 	 * hash table and inserting into it.
435 	 *
436 	 * However, it is not racy against itself because it keeps
437 	 * the mutex locked. It still seems to race against the
438 	 * above code that atomically inserts the station... That,
439 	 * however, is not true because the above code can only
440 	 * be invoked for IBSS interfaces, and the below code will
441 	 * not be -- and the two do not race against each other as
442 	 * the hash table also keys off the interface.
443 	 */
444 
445 	might_sleep();
446 
447 	mutex_lock(&local->sta_mtx);
448 
449 	spin_lock_irqsave(&local->sta_lock, flags);
450 	/* check if STA exists already */
451 	if (sta_info_get_bss(sdata, sta->sta.addr)) {
452 		spin_unlock_irqrestore(&local->sta_lock, flags);
453 		mutex_unlock(&local->sta_mtx);
454 		rcu_read_lock();
455 		err = -EEXIST;
456 		goto out_free;
457 	}
458 
459 	spin_unlock_irqrestore(&local->sta_lock, flags);
460 
461 	err = sta_info_finish_insert(sta, false);
462 	if (err) {
463 		mutex_unlock(&local->sta_mtx);
464 		rcu_read_lock();
465 		goto out_free;
466 	}
467 
468 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
469 	wiphy_debug(local->hw.wiphy, "Inserted STA %pM\n", sta->sta.addr);
470 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
471 
472 	/* move reference to rcu-protected */
473 	rcu_read_lock();
474 	mutex_unlock(&local->sta_mtx);
475 
476 	if (ieee80211_vif_is_mesh(&sdata->vif))
477 		mesh_accept_plinks_update(sdata);
478 
479 	return 0;
480  out_free:
481 	BUG_ON(!err);
482 	__sta_info_free(local, sta);
483 	return err;
484 }
485 
486 int sta_info_insert(struct sta_info *sta)
487 {
488 	int err = sta_info_insert_rcu(sta);
489 
490 	rcu_read_unlock();
491 
492 	return err;
493 }
494 
495 static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
496 {
497 	/*
498 	 * This format has been mandated by the IEEE specifications,
499 	 * so this line may not be changed to use the __set_bit() format.
500 	 */
501 	bss->tim[aid / 8] |= (1 << (aid % 8));
502 }
503 
504 static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
505 {
506 	/*
507 	 * This format has been mandated by the IEEE specifications,
508 	 * so this line may not be changed to use the __clear_bit() format.
509 	 */
510 	bss->tim[aid / 8] &= ~(1 << (aid % 8));
511 }
512 
513 static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
514 				   struct sta_info *sta)
515 {
516 	BUG_ON(!bss);
517 
518 	__bss_tim_set(bss, sta->sta.aid);
519 
520 	if (sta->local->ops->set_tim) {
521 		sta->local->tim_in_locked_section = true;
522 		drv_set_tim(sta->local, &sta->sta, true);
523 		sta->local->tim_in_locked_section = false;
524 	}
525 }
526 
527 void sta_info_set_tim_bit(struct sta_info *sta)
528 {
529 	unsigned long flags;
530 
531 	BUG_ON(!sta->sdata->bss);
532 
533 	spin_lock_irqsave(&sta->local->sta_lock, flags);
534 	__sta_info_set_tim_bit(sta->sdata->bss, sta);
535 	spin_unlock_irqrestore(&sta->local->sta_lock, flags);
536 }
537 
538 static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
539 				     struct sta_info *sta)
540 {
541 	BUG_ON(!bss);
542 
543 	__bss_tim_clear(bss, sta->sta.aid);
544 
545 	if (sta->local->ops->set_tim) {
546 		sta->local->tim_in_locked_section = true;
547 		drv_set_tim(sta->local, &sta->sta, false);
548 		sta->local->tim_in_locked_section = false;
549 	}
550 }
551 
552 void sta_info_clear_tim_bit(struct sta_info *sta)
553 {
554 	unsigned long flags;
555 
556 	BUG_ON(!sta->sdata->bss);
557 
558 	spin_lock_irqsave(&sta->local->sta_lock, flags);
559 	__sta_info_clear_tim_bit(sta->sdata->bss, sta);
560 	spin_unlock_irqrestore(&sta->local->sta_lock, flags);
561 }
562 
563 static int sta_info_buffer_expired(struct sta_info *sta,
564 				   struct sk_buff *skb)
565 {
566 	struct ieee80211_tx_info *info;
567 	int timeout;
568 
569 	if (!skb)
570 		return 0;
571 
572 	info = IEEE80211_SKB_CB(skb);
573 
574 	/* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
575 	timeout = (sta->listen_interval *
576 		   sta->sdata->vif.bss_conf.beacon_int *
577 		   32 / 15625) * HZ;
578 	if (timeout < STA_TX_BUFFER_EXPIRE)
579 		timeout = STA_TX_BUFFER_EXPIRE;
580 	return time_after(jiffies, info->control.jiffies + timeout);
581 }
582 
583 
584 static bool sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
585 					     struct sta_info *sta)
586 {
587 	unsigned long flags;
588 	struct sk_buff *skb;
589 
590 	if (skb_queue_empty(&sta->ps_tx_buf))
591 		return false;
592 
593 	for (;;) {
594 		spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
595 		skb = skb_peek(&sta->ps_tx_buf);
596 		if (sta_info_buffer_expired(sta, skb))
597 			skb = __skb_dequeue(&sta->ps_tx_buf);
598 		else
599 			skb = NULL;
600 		spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
601 
602 		if (!skb)
603 			break;
604 
605 		local->total_ps_buffered--;
606 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
607 		printk(KERN_DEBUG "Buffered frame expired (STA %pM)\n",
608 		       sta->sta.addr);
609 #endif
610 		dev_kfree_skb(skb);
611 
612 		if (skb_queue_empty(&sta->ps_tx_buf) &&
613 		    !test_sta_flags(sta, WLAN_STA_PS_DRIVER_BUF))
614 			sta_info_clear_tim_bit(sta);
615 	}
616 
617 	return true;
618 }
619 
620 static int __must_check __sta_info_destroy(struct sta_info *sta)
621 {
622 	struct ieee80211_local *local;
623 	struct ieee80211_sub_if_data *sdata;
624 	struct sk_buff *skb;
625 	unsigned long flags;
626 	int ret, i;
627 
628 	might_sleep();
629 
630 	if (!sta)
631 		return -ENOENT;
632 
633 	local = sta->local;
634 	sdata = sta->sdata;
635 
636 	/*
637 	 * Before removing the station from the driver and
638 	 * rate control, it might still start new aggregation
639 	 * sessions -- block that to make sure the tear-down
640 	 * will be sufficient.
641 	 */
642 	set_sta_flags(sta, WLAN_STA_BLOCK_BA);
643 	ieee80211_sta_tear_down_BA_sessions(sta, true);
644 
645 	spin_lock_irqsave(&local->sta_lock, flags);
646 	ret = sta_info_hash_del(local, sta);
647 	/* this might still be the pending list ... which is fine */
648 	if (!ret)
649 		list_del(&sta->list);
650 	spin_unlock_irqrestore(&local->sta_lock, flags);
651 	if (ret)
652 		return ret;
653 
654 	mutex_lock(&local->key_mtx);
655 	for (i = 0; i < NUM_DEFAULT_KEYS; i++)
656 		__ieee80211_key_free(key_mtx_dereference(local, sta->gtk[i]));
657 	if (sta->ptk)
658 		__ieee80211_key_free(key_mtx_dereference(local, sta->ptk));
659 	mutex_unlock(&local->key_mtx);
660 
661 	sta->dead = true;
662 
663 	if (test_and_clear_sta_flags(sta,
664 				WLAN_STA_PS_STA | WLAN_STA_PS_DRIVER)) {
665 		BUG_ON(!sdata->bss);
666 
667 		atomic_dec(&sdata->bss->num_sta_ps);
668 		__sta_info_clear_tim_bit(sdata->bss, sta);
669 	}
670 
671 	local->num_sta--;
672 	local->sta_generation++;
673 
674 	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
675 		rcu_assign_pointer(sdata->u.vlan.sta, NULL);
676 
677 	if (sta->uploaded) {
678 		if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
679 			sdata = container_of(sdata->bss,
680 					     struct ieee80211_sub_if_data,
681 					     u.ap);
682 		drv_sta_remove(local, sdata, &sta->sta);
683 		sdata = sta->sdata;
684 	}
685 
686 	/*
687 	 * At this point, after we wait for an RCU grace period,
688 	 * neither mac80211 nor the driver can reference this
689 	 * sta struct any more except by still existing timers
690 	 * associated with this station that we clean up below.
691 	 */
692 	synchronize_rcu();
693 
694 #ifdef CONFIG_MAC80211_MESH
695 	if (ieee80211_vif_is_mesh(&sdata->vif))
696 		mesh_accept_plinks_update(sdata);
697 #endif
698 
699 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
700 	wiphy_debug(local->hw.wiphy, "Removed STA %pM\n", sta->sta.addr);
701 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
702 	cancel_work_sync(&sta->drv_unblock_wk);
703 
704 	cfg80211_del_sta(sdata->dev, sta->sta.addr, GFP_KERNEL);
705 
706 	rate_control_remove_sta_debugfs(sta);
707 	ieee80211_sta_debugfs_remove(sta);
708 
709 #ifdef CONFIG_MAC80211_MESH
710 	if (ieee80211_vif_is_mesh(&sta->sdata->vif)) {
711 		mesh_plink_deactivate(sta);
712 		del_timer_sync(&sta->plink_timer);
713 	}
714 #endif
715 
716 	while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
717 		local->total_ps_buffered--;
718 		dev_kfree_skb_any(skb);
719 	}
720 
721 	while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
722 		dev_kfree_skb_any(skb);
723 
724 	__sta_info_free(local, sta);
725 
726 	return 0;
727 }
728 
729 int sta_info_destroy_addr(struct ieee80211_sub_if_data *sdata, const u8 *addr)
730 {
731 	struct sta_info *sta;
732 	int ret;
733 
734 	mutex_lock(&sdata->local->sta_mtx);
735 	sta = sta_info_get(sdata, addr);
736 	ret = __sta_info_destroy(sta);
737 	mutex_unlock(&sdata->local->sta_mtx);
738 
739 	return ret;
740 }
741 
742 int sta_info_destroy_addr_bss(struct ieee80211_sub_if_data *sdata,
743 			      const u8 *addr)
744 {
745 	struct sta_info *sta;
746 	int ret;
747 
748 	mutex_lock(&sdata->local->sta_mtx);
749 	sta = sta_info_get_bss(sdata, addr);
750 	ret = __sta_info_destroy(sta);
751 	mutex_unlock(&sdata->local->sta_mtx);
752 
753 	return ret;
754 }
755 
756 static void sta_info_cleanup(unsigned long data)
757 {
758 	struct ieee80211_local *local = (struct ieee80211_local *) data;
759 	struct sta_info *sta;
760 	bool timer_needed = false;
761 
762 	rcu_read_lock();
763 	list_for_each_entry_rcu(sta, &local->sta_list, list)
764 		if (sta_info_cleanup_expire_buffered(local, sta))
765 			timer_needed = true;
766 	rcu_read_unlock();
767 
768 	if (local->quiescing)
769 		return;
770 
771 	if (!timer_needed)
772 		return;
773 
774 	mod_timer(&local->sta_cleanup,
775 		  round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL));
776 }
777 
778 void sta_info_init(struct ieee80211_local *local)
779 {
780 	spin_lock_init(&local->sta_lock);
781 	mutex_init(&local->sta_mtx);
782 	INIT_LIST_HEAD(&local->sta_list);
783 	INIT_LIST_HEAD(&local->sta_pending_list);
784 	INIT_WORK(&local->sta_finish_work, sta_info_finish_work);
785 
786 	setup_timer(&local->sta_cleanup, sta_info_cleanup,
787 		    (unsigned long)local);
788 }
789 
790 void sta_info_stop(struct ieee80211_local *local)
791 {
792 	del_timer(&local->sta_cleanup);
793 	sta_info_flush(local, NULL);
794 }
795 
796 /**
797  * sta_info_flush - flush matching STA entries from the STA table
798  *
799  * Returns the number of removed STA entries.
800  *
801  * @local: local interface data
802  * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
803  */
804 int sta_info_flush(struct ieee80211_local *local,
805 		   struct ieee80211_sub_if_data *sdata)
806 {
807 	struct sta_info *sta, *tmp;
808 	int ret = 0;
809 
810 	might_sleep();
811 
812 	mutex_lock(&local->sta_mtx);
813 
814 	sta_info_finish_pending(local);
815 
816 	list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
817 		if (!sdata || sdata == sta->sdata)
818 			WARN_ON(__sta_info_destroy(sta));
819 	}
820 	mutex_unlock(&local->sta_mtx);
821 
822 	return ret;
823 }
824 
825 void ieee80211_sta_expire(struct ieee80211_sub_if_data *sdata,
826 			  unsigned long exp_time)
827 {
828 	struct ieee80211_local *local = sdata->local;
829 	struct sta_info *sta, *tmp;
830 
831 	mutex_lock(&local->sta_mtx);
832 	list_for_each_entry_safe(sta, tmp, &local->sta_list, list)
833 		if (time_after(jiffies, sta->last_rx + exp_time)) {
834 #ifdef CONFIG_MAC80211_IBSS_DEBUG
835 			printk(KERN_DEBUG "%s: expiring inactive STA %pM\n",
836 			       sdata->name, sta->sta.addr);
837 #endif
838 			WARN_ON(__sta_info_destroy(sta));
839 		}
840 	mutex_unlock(&local->sta_mtx);
841 }
842 
843 struct ieee80211_sta *ieee80211_find_sta_by_ifaddr(struct ieee80211_hw *hw,
844 					       const u8 *addr,
845 					       const u8 *localaddr)
846 {
847 	struct sta_info *sta, *nxt;
848 
849 	/*
850 	 * Just return a random station if localaddr is NULL
851 	 * ... first in list.
852 	 */
853 	for_each_sta_info(hw_to_local(hw), addr, sta, nxt) {
854 		if (localaddr &&
855 		    compare_ether_addr(sta->sdata->vif.addr, localaddr) != 0)
856 			continue;
857 		if (!sta->uploaded)
858 			return NULL;
859 		return &sta->sta;
860 	}
861 
862 	return NULL;
863 }
864 EXPORT_SYMBOL_GPL(ieee80211_find_sta_by_ifaddr);
865 
866 struct ieee80211_sta *ieee80211_find_sta(struct ieee80211_vif *vif,
867 					 const u8 *addr)
868 {
869 	struct sta_info *sta;
870 
871 	if (!vif)
872 		return NULL;
873 
874 	sta = sta_info_get_bss(vif_to_sdata(vif), addr);
875 	if (!sta)
876 		return NULL;
877 
878 	if (!sta->uploaded)
879 		return NULL;
880 
881 	return &sta->sta;
882 }
883 EXPORT_SYMBOL(ieee80211_find_sta);
884 
885 static void clear_sta_ps_flags(void *_sta)
886 {
887 	struct sta_info *sta = _sta;
888 
889 	clear_sta_flags(sta, WLAN_STA_PS_DRIVER | WLAN_STA_PS_STA);
890 }
891 
892 /* powersave support code */
893 void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
894 {
895 	struct ieee80211_sub_if_data *sdata = sta->sdata;
896 	struct ieee80211_local *local = sdata->local;
897 	int sent, buffered;
898 
899 	clear_sta_flags(sta, WLAN_STA_PS_DRIVER_BUF);
900 	if (!(local->hw.flags & IEEE80211_HW_AP_LINK_PS))
901 		drv_sta_notify(local, sdata, STA_NOTIFY_AWAKE, &sta->sta);
902 
903 	if (!skb_queue_empty(&sta->ps_tx_buf))
904 		sta_info_clear_tim_bit(sta);
905 
906 	/* Send all buffered frames to the station */
907 	sent = ieee80211_add_pending_skbs(local, &sta->tx_filtered);
908 	buffered = ieee80211_add_pending_skbs_fn(local, &sta->ps_tx_buf,
909 						 clear_sta_ps_flags, sta);
910 	sent += buffered;
911 	local->total_ps_buffered -= buffered;
912 
913 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
914 	printk(KERN_DEBUG "%s: STA %pM aid %d sending %d filtered/%d PS frames "
915 	       "since STA not sleeping anymore\n", sdata->name,
916 	       sta->sta.addr, sta->sta.aid, sent - buffered, buffered);
917 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
918 }
919 
920 void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta)
921 {
922 	struct ieee80211_sub_if_data *sdata = sta->sdata;
923 	struct ieee80211_local *local = sdata->local;
924 	struct sk_buff *skb;
925 	int no_pending_pkts;
926 
927 	skb = skb_dequeue(&sta->tx_filtered);
928 	if (!skb) {
929 		skb = skb_dequeue(&sta->ps_tx_buf);
930 		if (skb)
931 			local->total_ps_buffered--;
932 	}
933 	no_pending_pkts = skb_queue_empty(&sta->tx_filtered) &&
934 		skb_queue_empty(&sta->ps_tx_buf);
935 
936 	if (skb) {
937 		struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
938 		struct ieee80211_hdr *hdr =
939 			(struct ieee80211_hdr *) skb->data;
940 
941 		/*
942 		 * Tell TX path to send this frame even though the STA may
943 		 * still remain is PS mode after this frame exchange.
944 		 */
945 		info->flags |= IEEE80211_TX_CTL_PSPOLL_RESPONSE;
946 
947 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
948 		printk(KERN_DEBUG "STA %pM aid %d: PS Poll (entries after %d)\n",
949 		       sta->sta.addr, sta->sta.aid,
950 		       skb_queue_len(&sta->ps_tx_buf));
951 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
952 
953 		/* Use MoreData flag to indicate whether there are more
954 		 * buffered frames for this STA */
955 		if (no_pending_pkts)
956 			hdr->frame_control &= cpu_to_le16(~IEEE80211_FCTL_MOREDATA);
957 		else
958 			hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_MOREDATA);
959 
960 		ieee80211_add_pending_skb(local, skb);
961 
962 		if (no_pending_pkts)
963 			sta_info_clear_tim_bit(sta);
964 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
965 	} else {
966 		/*
967 		 * FIXME: This can be the result of a race condition between
968 		 *	  us expiring a frame and the station polling for it.
969 		 *	  Should we send it a null-func frame indicating we
970 		 *	  have nothing buffered for it?
971 		 */
972 		printk(KERN_DEBUG "%s: STA %pM sent PS Poll even "
973 		       "though there are no buffered frames for it\n",
974 		       sdata->name, sta->sta.addr);
975 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
976 	}
977 }
978 
979 void ieee80211_sta_block_awake(struct ieee80211_hw *hw,
980 			       struct ieee80211_sta *pubsta, bool block)
981 {
982 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
983 
984 	trace_api_sta_block_awake(sta->local, pubsta, block);
985 
986 	if (block)
987 		set_sta_flags(sta, WLAN_STA_PS_DRIVER);
988 	else if (test_sta_flags(sta, WLAN_STA_PS_DRIVER))
989 		ieee80211_queue_work(hw, &sta->drv_unblock_wk);
990 }
991 EXPORT_SYMBOL(ieee80211_sta_block_awake);
992 
993 void ieee80211_sta_set_tim(struct ieee80211_sta *pubsta)
994 {
995 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
996 
997 	set_sta_flags(sta, WLAN_STA_PS_DRIVER_BUF);
998 	sta_info_set_tim_bit(sta);
999 }
1000 EXPORT_SYMBOL(ieee80211_sta_set_tim);
1001