2 * Copyright 2002-2005, Instant802 Networks, Inc.
3 * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
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.
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>
20 #include <net/mac80211.h>
21 #include "ieee80211_i.h"
22 #include "ieee80211_rate.h"
24 #include "debugfs_sta.h"
28 * DOC: STA information lifetime rules
30 * STA info structures (&struct sta_info) are managed in a hash table
31 * for faster lookup and a list for iteration. They are managed using
32 * RCU, i.e. access to the list and hash table is protected by RCU.
34 * Upon allocating a STA info structure with sta_info_alloc(), the caller owns
35 * that structure. It must then either destroy it using sta_info_destroy()
36 * (which is pretty useless) or insert it into the hash table using
37 * sta_info_insert() which demotes the reference from ownership to a regular
38 * RCU-protected reference; if the function is called without protection by an
39 * RCU critical section the reference is instantly invalidated. Note that the
40 * caller may not do much with the STA info before inserting it, in particular,
41 * it may not start any mesh peer link management or add encryption keys.
43 * When the insertion fails (sta_info_insert()) returns non-zero), the
44 * structure will have been freed by sta_info_insert()!
46 * Because there are debugfs entries for each station, and adding those
47 * must be able to sleep, it is also possible to "pin" a station entry,
48 * that means it can be removed from the hash table but not be freed.
49 * See the comment in __sta_info_unlink() for more information, this is
50 * an internal capability only.
52 * In order to remove a STA info structure, the caller needs to first
53 * unlink it (sta_info_unlink()) from the list and hash tables and
54 * then destroy it while holding the RTNL; sta_info_destroy() will wait
55 * for an RCU grace period to elapse before actually freeing it. Due to
56 * the pinning and the possibility of multiple callers trying to remove
57 * the same STA info at the same time, sta_info_unlink() can clear the
58 * STA info pointer it is passed to indicate that the STA info is owned
59 * by somebody else now.
61 * If sta_info_unlink() did not clear the pointer then the caller owns
62 * the STA info structure now and is responsible of destroying it with
63 * a call to sta_info_destroy(), not before RCU synchronisation, of
64 * course. Note that sta_info_destroy() must be protected by the RTNL.
66 * In all other cases, there is no concept of ownership on a STA entry,
67 * each structure is owned by the global hash table/list until it is
68 * removed. All users of the structure need to be RCU protected so that
69 * the structure won't be freed before they are done using it.
72 /* Caller must hold local->sta_lock */
73 static int sta_info_hash_del(struct ieee80211_local *local,
78 s = local->sta_hash[STA_HASH(sta->addr)];
82 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)],
87 while (s->hnext && s->hnext != sta)
90 rcu_assign_pointer(s->hnext, sta->hnext);
97 /* protected by RCU */
98 static struct sta_info *__sta_info_find(struct ieee80211_local *local,
101 struct sta_info *sta;
103 sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
105 if (compare_ether_addr(sta->addr, addr) == 0)
107 sta = rcu_dereference(sta->hnext);
112 struct sta_info *sta_info_get(struct ieee80211_local *local, u8 *addr)
114 return __sta_info_find(local, addr);
116 EXPORT_SYMBOL(sta_info_get);
118 struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx,
119 struct net_device *dev)
121 struct sta_info *sta;
124 list_for_each_entry_rcu(sta, &local->sta_list, list) {
125 if (dev && dev != sta->sdata->dev)
138 * __sta_info_free - internal STA free helper
140 * @sta: STA info to free
142 * This function must undo everything done by sta_info_alloc()
143 * that may happen before sta_info_insert().
145 static void __sta_info_free(struct ieee80211_local *local,
146 struct sta_info *sta)
148 DECLARE_MAC_BUF(mbuf);
150 rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
151 rate_control_put(sta->rate_ctrl);
153 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
154 printk(KERN_DEBUG "%s: Destroyed STA %s\n",
155 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
156 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
161 void sta_info_destroy(struct sta_info *sta)
163 struct ieee80211_local *local;
175 rate_control_remove_sta_debugfs(sta);
176 ieee80211_sta_debugfs_remove(sta);
178 #ifdef CONFIG_MAC80211_MESH
179 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
180 mesh_plink_deactivate(sta);
184 * NOTE: This will call synchronize_rcu() internally to
185 * make sure no key references can be in use. We rely on
186 * that here for the mesh code!
188 ieee80211_key_free(sta->key);
191 #ifdef CONFIG_MAC80211_MESH
192 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
193 del_timer_sync(&sta->plink_timer);
196 while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
197 local->total_ps_buffered--;
198 dev_kfree_skb_any(skb);
201 while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
202 dev_kfree_skb_any(skb);
204 for (i = 0; i < STA_TID_NUM; i++) {
205 spin_lock_bh(&sta->ampdu_mlme.ampdu_rx);
206 if (sta->ampdu_mlme.tid_rx[i])
207 del_timer_sync(&sta->ampdu_mlme.tid_rx[i]->session_timer);
208 spin_unlock_bh(&sta->ampdu_mlme.ampdu_rx);
209 spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
210 if (sta->ampdu_mlme.tid_tx[i])
211 del_timer_sync(&sta->ampdu_mlme.tid_tx[i]->addba_resp_timer);
212 spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
215 __sta_info_free(local, sta);
219 /* Caller must hold local->sta_lock */
220 static void sta_info_hash_add(struct ieee80211_local *local,
221 struct sta_info *sta)
223 sta->hnext = local->sta_hash[STA_HASH(sta->addr)];
224 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], sta);
227 struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
230 struct ieee80211_local *local = sdata->local;
231 struct sta_info *sta;
233 DECLARE_MAC_BUF(mbuf);
235 sta = kzalloc(sizeof(*sta), gfp);
239 memcpy(sta->addr, addr, ETH_ALEN);
243 sta->rate_ctrl = rate_control_get(local->rate_ctrl);
244 sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
246 if (!sta->rate_ctrl_priv) {
247 rate_control_put(sta->rate_ctrl);
252 spin_lock_init(&sta->ampdu_mlme.ampdu_rx);
253 spin_lock_init(&sta->ampdu_mlme.ampdu_tx);
254 for (i = 0; i < STA_TID_NUM; i++) {
255 /* timer_to_tid must be initialized with identity mapping to
256 * enable session_timer's data differentiation. refer to
257 * sta_rx_agg_session_timer_expired for useage */
258 sta->timer_to_tid[i] = i;
259 /* tid to tx queue: initialize according to HW (0 is valid) */
260 sta->tid_to_tx_q[i] = local->hw.queues;
262 sta->ampdu_mlme.tid_state_rx[i] = HT_AGG_STATE_IDLE;
263 sta->ampdu_mlme.tid_rx[i] = NULL;
265 sta->ampdu_mlme.tid_state_tx[i] = HT_AGG_STATE_IDLE;
266 sta->ampdu_mlme.tid_tx[i] = NULL;
267 sta->ampdu_mlme.addba_req_num[i] = 0;
269 skb_queue_head_init(&sta->ps_tx_buf);
270 skb_queue_head_init(&sta->tx_filtered);
272 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
273 printk(KERN_DEBUG "%s: Allocated STA %s\n",
274 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
275 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
277 #ifdef CONFIG_MAC80211_MESH
278 sta->plink_state = PLINK_LISTEN;
279 spin_lock_init(&sta->plink_lock);
280 init_timer(&sta->plink_timer);
286 int sta_info_insert(struct sta_info *sta)
288 struct ieee80211_local *local = sta->local;
289 struct ieee80211_sub_if_data *sdata = sta->sdata;
292 DECLARE_MAC_BUF(mac);
295 * Can't be a WARN_ON because it can be triggered through a race:
296 * something inserts a STA (on one CPU) without holding the RTNL
297 * and another CPU turns off the net device.
299 if (unlikely(!netif_running(sdata->dev))) {
304 if (WARN_ON(compare_ether_addr(sta->addr, sdata->dev->dev_addr) == 0 ||
305 is_multicast_ether_addr(sta->addr))) {
310 spin_lock_irqsave(&local->sta_lock, flags);
311 /* check if STA exists already */
312 if (__sta_info_find(local, sta->addr)) {
313 spin_unlock_irqrestore(&local->sta_lock, flags);
317 list_add(&sta->list, &local->sta_list);
319 sta_info_hash_add(local, sta);
322 if (local->ops->sta_notify) {
323 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
324 sdata = sdata->u.vlan.ap;
326 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
327 STA_NOTIFY_ADD, sta->addr);
330 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
331 printk(KERN_DEBUG "%s: Inserted STA %s\n",
332 wiphy_name(local->hw.wiphy), print_mac(mac, sta->addr));
333 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
335 spin_unlock_irqrestore(&local->sta_lock, flags);
337 #ifdef CONFIG_MAC80211_DEBUGFS
339 * Debugfs entry adding might sleep, so schedule process
340 * context task for adding entry for STAs that do not yet
342 * NOTE: due to auto-freeing semantics this may only be done
343 * if the insertion is successful!
345 queue_work(local->hw.workqueue, &local->sta_debugfs_add);
348 if (ieee80211_vif_is_mesh(&sdata->vif))
349 mesh_accept_plinks_update(sdata);
354 __sta_info_free(local, sta);
358 static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
361 * This format has been mandated by the IEEE specifications,
362 * so this line may not be changed to use the __set_bit() format.
364 bss->tim[aid / 8] |= (1 << (aid % 8));
367 static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
370 * This format has been mandated by the IEEE specifications,
371 * so this line may not be changed to use the __clear_bit() format.
373 bss->tim[aid / 8] &= ~(1 << (aid % 8));
376 static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
377 struct sta_info *sta)
380 __bss_tim_set(bss, sta->aid);
381 if (sta->local->ops->set_tim) {
382 sta->local->tim_in_locked_section = true;
383 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 1);
384 sta->local->tim_in_locked_section = false;
388 void sta_info_set_tim_bit(struct sta_info *sta)
392 spin_lock_irqsave(&sta->local->sta_lock, flags);
393 __sta_info_set_tim_bit(sta->sdata->bss, sta);
394 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
397 static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
398 struct sta_info *sta)
401 __bss_tim_clear(bss, sta->aid);
402 if (sta->local->ops->set_tim) {
403 sta->local->tim_in_locked_section = true;
404 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 0);
405 sta->local->tim_in_locked_section = false;
409 void sta_info_clear_tim_bit(struct sta_info *sta)
413 spin_lock_irqsave(&sta->local->sta_lock, flags);
414 __sta_info_clear_tim_bit(sta->sdata->bss, sta);
415 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
419 * See comment in __sta_info_unlink,
420 * caller must hold local->sta_lock.
422 static void __sta_info_pin(struct sta_info *sta)
424 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
425 sta->pin_status = STA_INFO_PIN_STAT_PINNED;
429 * See comment in __sta_info_unlink, returns sta if it
430 * needs to be destroyed.
432 static struct sta_info *__sta_info_unpin(struct sta_info *sta)
434 struct sta_info *ret = NULL;
437 spin_lock_irqsave(&sta->local->sta_lock, flags);
438 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
439 sta->pin_status != STA_INFO_PIN_STAT_PINNED);
440 if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
442 sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
443 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
448 static void __sta_info_unlink(struct sta_info **sta)
450 struct ieee80211_local *local = (*sta)->local;
451 struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
452 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
453 DECLARE_MAC_BUF(mbuf);
456 * pull caller's reference if we're already gone.
458 if (sta_info_hash_del(local, *sta)) {
464 * Also pull caller's reference if the STA is pinned by the
465 * task that is adding the debugfs entries. In that case, we
466 * leave the STA "to be freed".
468 * The rules are not trivial, but not too complex either:
469 * (1) pin_status is only modified under the sta_lock
470 * (2) sta_info_debugfs_add_work() will set the status
471 * to PINNED when it found an item that needs a new
472 * debugfs directory created. In that case, that item
473 * must not be freed although all *RCU* users are done
474 * with it. Hence, we tell the caller of _unlink()
475 * that the item is already gone (as can happen when
476 * two tasks try to unlink/destroy at the same time)
477 * (3) We set the pin_status to DESTROY here when we
479 * (4) sta_info_debugfs_add_work() will reset the pin_status
480 * from PINNED to NORMAL when it is done with the item,
481 * but will check for DESTROY before resetting it in
482 * which case it will free the item.
484 if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
485 (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
490 list_del(&(*sta)->list);
492 if ((*sta)->flags & WLAN_STA_PS) {
493 (*sta)->flags &= ~WLAN_STA_PS;
495 atomic_dec(&sdata->bss->num_sta_ps);
496 __sta_info_clear_tim_bit(sdata->bss, *sta);
501 if (local->ops->sta_notify) {
502 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
503 sdata = sdata->u.vlan.ap;
505 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
506 STA_NOTIFY_REMOVE, (*sta)->addr);
509 if (ieee80211_vif_is_mesh(&sdata->vif)) {
510 mesh_accept_plinks_update(sdata);
511 #ifdef CONFIG_MAC80211_MESH
512 del_timer(&(*sta)->plink_timer);
516 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
517 printk(KERN_DEBUG "%s: Removed STA %s\n",
518 wiphy_name(local->hw.wiphy), print_mac(mbuf, (*sta)->addr));
519 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
522 void sta_info_unlink(struct sta_info **sta)
524 struct ieee80211_local *local = (*sta)->local;
527 spin_lock_irqsave(&local->sta_lock, flags);
528 __sta_info_unlink(sta);
529 spin_unlock_irqrestore(&local->sta_lock, flags);
532 static inline int sta_info_buffer_expired(struct ieee80211_local *local,
533 struct sta_info *sta,
536 struct ieee80211_tx_packet_data *pkt_data;
542 pkt_data = (struct ieee80211_tx_packet_data *) skb->cb;
544 /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
545 timeout = (sta->listen_interval * local->hw.conf.beacon_int * 32 /
547 if (timeout < STA_TX_BUFFER_EXPIRE)
548 timeout = STA_TX_BUFFER_EXPIRE;
549 return time_after(jiffies, pkt_data->jiffies + timeout);
553 static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
554 struct sta_info *sta)
558 struct ieee80211_sub_if_data *sdata;
559 DECLARE_MAC_BUF(mac);
561 if (skb_queue_empty(&sta->ps_tx_buf))
565 spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
566 skb = skb_peek(&sta->ps_tx_buf);
567 if (sta_info_buffer_expired(local, sta, skb))
568 skb = __skb_dequeue(&sta->ps_tx_buf);
571 spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
577 local->total_ps_buffered--;
578 printk(KERN_DEBUG "Buffered frame expired (STA "
579 "%s)\n", print_mac(mac, sta->addr));
582 if (skb_queue_empty(&sta->ps_tx_buf))
583 sta_info_clear_tim_bit(sta);
588 static void sta_info_cleanup(unsigned long data)
590 struct ieee80211_local *local = (struct ieee80211_local *) data;
591 struct sta_info *sta;
594 list_for_each_entry_rcu(sta, &local->sta_list, list)
595 sta_info_cleanup_expire_buffered(local, sta);
598 local->sta_cleanup.expires =
599 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
600 add_timer(&local->sta_cleanup);
603 #ifdef CONFIG_MAC80211_DEBUGFS
604 static void sta_info_debugfs_add_work(struct work_struct *work)
606 struct ieee80211_local *local =
607 container_of(work, struct ieee80211_local, sta_debugfs_add);
608 struct sta_info *sta, *tmp;
614 spin_lock_irqsave(&local->sta_lock, flags);
615 list_for_each_entry(tmp, &local->sta_list, list) {
616 if (!tmp->debugfs.dir) {
622 spin_unlock_irqrestore(&local->sta_lock, flags);
627 ieee80211_sta_debugfs_add(sta);
628 rate_control_add_sta_debugfs(sta);
630 sta = __sta_info_unpin(sta);
634 sta_info_destroy(sta);
640 void sta_info_init(struct ieee80211_local *local)
642 spin_lock_init(&local->sta_lock);
643 INIT_LIST_HEAD(&local->sta_list);
645 setup_timer(&local->sta_cleanup, sta_info_cleanup,
646 (unsigned long)local);
647 local->sta_cleanup.expires =
648 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
650 #ifdef CONFIG_MAC80211_DEBUGFS
651 INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
655 int sta_info_start(struct ieee80211_local *local)
657 add_timer(&local->sta_cleanup);
661 void sta_info_stop(struct ieee80211_local *local)
663 del_timer(&local->sta_cleanup);
664 sta_info_flush(local, NULL);
668 * sta_info_flush - flush matching STA entries from the STA table
670 * Returns the number of removed STA entries.
672 * @local: local interface data
673 * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
675 int sta_info_flush(struct ieee80211_local *local,
676 struct ieee80211_sub_if_data *sdata)
678 struct sta_info *sta, *tmp;
685 spin_lock_irqsave(&local->sta_lock, flags);
686 list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
687 if (!sdata || sdata == sta->sdata) {
688 __sta_info_unlink(&sta);
690 list_add_tail(&sta->list, &tmp_list);
695 spin_unlock_irqrestore(&local->sta_lock, flags);
699 list_for_each_entry_safe(sta, tmp, &tmp_list, list)
700 sta_info_destroy(sta);