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"
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; sta_info_destroy() will wait for an RCU grace period
55 * to elapse before actually freeing it. Due to the pinning and the
56 * possibility of multiple callers trying to remove the same STA info at
57 * the same time, sta_info_unlink() can clear the STA info pointer it is
58 * passed to indicate that the STA info is owned by somebody else now.
60 * If sta_info_unlink() did not clear the pointer then the caller owns
61 * the STA info structure now and is responsible of destroying it with
62 * a call to sta_info_destroy().
64 * In all other cases, there is no concept of ownership on a STA entry,
65 * each structure is owned by the global hash table/list until it is
66 * removed. All users of the structure need to be RCU protected so that
67 * the structure won't be freed before they are done using it.
70 /* Caller must hold local->sta_lock */
71 static int sta_info_hash_del(struct ieee80211_local *local,
76 s = local->sta_hash[STA_HASH(sta->addr)];
80 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)],
85 while (s->hnext && s->hnext != sta)
88 rcu_assign_pointer(s->hnext, sta->hnext);
95 /* protected by RCU */
96 static struct sta_info *__sta_info_find(struct ieee80211_local *local,
101 sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
103 if (compare_ether_addr(sta->addr, addr) == 0)
105 sta = rcu_dereference(sta->hnext);
110 struct sta_info *sta_info_get(struct ieee80211_local *local, u8 *addr)
112 return __sta_info_find(local, addr);
114 EXPORT_SYMBOL(sta_info_get);
116 struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx,
117 struct net_device *dev)
119 struct sta_info *sta;
122 list_for_each_entry_rcu(sta, &local->sta_list, list) {
123 if (dev && dev != sta->sdata->dev)
136 * __sta_info_free - internal STA free helper
138 * @sta: STA info to free
140 * This function must undo everything done by sta_info_alloc()
141 * that may happen before sta_info_insert().
143 static void __sta_info_free(struct ieee80211_local *local,
144 struct sta_info *sta)
146 DECLARE_MAC_BUF(mbuf);
148 rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
149 rate_control_put(sta->rate_ctrl);
151 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
152 printk(KERN_DEBUG "%s: Destroyed STA %s\n",
153 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
154 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
159 void sta_info_destroy(struct sta_info *sta)
161 struct ieee80211_local *local;
172 rate_control_remove_sta_debugfs(sta);
173 ieee80211_sta_debugfs_remove(sta);
175 #ifdef CONFIG_MAC80211_MESH
176 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
177 mesh_plink_deactivate(sta);
181 * We have only unlinked the key, and actually destroying it
182 * may mean it is removed from hardware which requires that
183 * the key->sta pointer is still valid, so flush the key todo
186 * ieee80211_key_todo() will synchronize_rcu() so after this
187 * nothing can reference this sta struct any more.
189 ieee80211_key_todo();
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->lock);
206 if (sta->ampdu_mlme.tid_rx[i])
207 del_timer_sync(&sta->ampdu_mlme.tid_rx[i]->session_timer);
208 if (sta->ampdu_mlme.tid_tx[i])
209 del_timer_sync(&sta->ampdu_mlme.tid_tx[i]->addba_resp_timer);
210 spin_unlock_bh(&sta->lock);
213 __sta_info_free(local, sta);
217 /* Caller must hold local->sta_lock */
218 static void sta_info_hash_add(struct ieee80211_local *local,
219 struct sta_info *sta)
221 sta->hnext = local->sta_hash[STA_HASH(sta->addr)];
222 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], sta);
225 struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
228 struct ieee80211_local *local = sdata->local;
229 struct sta_info *sta;
231 DECLARE_MAC_BUF(mbuf);
233 sta = kzalloc(sizeof(*sta), gfp);
237 spin_lock_init(&sta->lock);
238 spin_lock_init(&sta->flaglock);
240 memcpy(sta->addr, addr, ETH_ALEN);
244 sta->rate_ctrl = rate_control_get(local->rate_ctrl);
245 sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
247 if (!sta->rate_ctrl_priv) {
248 rate_control_put(sta->rate_ctrl);
253 for (i = 0; i < STA_TID_NUM; i++) {
254 /* timer_to_tid must be initialized with identity mapping to
255 * enable session_timer's data differentiation. refer to
256 * sta_rx_agg_session_timer_expired for useage */
257 sta->timer_to_tid[i] = i;
258 /* tid to tx queue: initialize according to HW (0 is valid) */
259 sta->tid_to_tx_q[i] = ieee80211_num_queues(&local->hw);
261 sta->ampdu_mlme.tid_state_rx[i] = HT_AGG_STATE_IDLE;
262 sta->ampdu_mlme.tid_rx[i] = NULL;
264 sta->ampdu_mlme.tid_state_tx[i] = HT_AGG_STATE_IDLE;
265 sta->ampdu_mlme.tid_tx[i] = NULL;
266 sta->ampdu_mlme.addba_req_num[i] = 0;
268 skb_queue_head_init(&sta->ps_tx_buf);
269 skb_queue_head_init(&sta->tx_filtered);
271 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
272 printk(KERN_DEBUG "%s: Allocated STA %s\n",
273 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
274 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
276 #ifdef CONFIG_MAC80211_MESH
277 sta->plink_state = PLINK_LISTEN;
278 init_timer(&sta->plink_timer);
284 int sta_info_insert(struct sta_info *sta)
286 struct ieee80211_local *local = sta->local;
287 struct ieee80211_sub_if_data *sdata = sta->sdata;
290 DECLARE_MAC_BUF(mac);
293 * Can't be a WARN_ON because it can be triggered through a race:
294 * something inserts a STA (on one CPU) without holding the RTNL
295 * and another CPU turns off the net device.
297 if (unlikely(!netif_running(sdata->dev))) {
302 if (WARN_ON(compare_ether_addr(sta->addr, sdata->dev->dev_addr) == 0 ||
303 is_multicast_ether_addr(sta->addr))) {
308 spin_lock_irqsave(&local->sta_lock, flags);
309 /* check if STA exists already */
310 if (__sta_info_find(local, sta->addr)) {
311 spin_unlock_irqrestore(&local->sta_lock, flags);
315 list_add(&sta->list, &local->sta_list);
317 sta_info_hash_add(local, sta);
320 if (local->ops->sta_notify) {
321 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
322 sdata = sdata->u.vlan.ap;
324 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
325 STA_NOTIFY_ADD, sta->addr);
328 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
329 printk(KERN_DEBUG "%s: Inserted STA %s\n",
330 wiphy_name(local->hw.wiphy), print_mac(mac, sta->addr));
331 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
333 spin_unlock_irqrestore(&local->sta_lock, flags);
335 #ifdef CONFIG_MAC80211_DEBUGFS
337 * Debugfs entry adding might sleep, so schedule process
338 * context task for adding entry for STAs that do not yet
340 * NOTE: due to auto-freeing semantics this may only be done
341 * if the insertion is successful!
343 schedule_work(&local->sta_debugfs_add);
346 if (ieee80211_vif_is_mesh(&sdata->vif))
347 mesh_accept_plinks_update(sdata);
352 __sta_info_free(local, sta);
356 static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
359 * This format has been mandated by the IEEE specifications,
360 * so this line may not be changed to use the __set_bit() format.
362 bss->tim[aid / 8] |= (1 << (aid % 8));
365 static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
368 * This format has been mandated by the IEEE specifications,
369 * so this line may not be changed to use the __clear_bit() format.
371 bss->tim[aid / 8] &= ~(1 << (aid % 8));
374 static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
375 struct sta_info *sta)
378 __bss_tim_set(bss, sta->aid);
379 if (sta->local->ops->set_tim) {
380 sta->local->tim_in_locked_section = true;
381 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 1);
382 sta->local->tim_in_locked_section = false;
386 void sta_info_set_tim_bit(struct sta_info *sta)
390 spin_lock_irqsave(&sta->local->sta_lock, flags);
391 __sta_info_set_tim_bit(sta->sdata->bss, sta);
392 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
395 static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
396 struct sta_info *sta)
399 __bss_tim_clear(bss, sta->aid);
400 if (sta->local->ops->set_tim) {
401 sta->local->tim_in_locked_section = true;
402 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 0);
403 sta->local->tim_in_locked_section = false;
407 void sta_info_clear_tim_bit(struct sta_info *sta)
411 spin_lock_irqsave(&sta->local->sta_lock, flags);
412 __sta_info_clear_tim_bit(sta->sdata->bss, sta);
413 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
416 void __sta_info_unlink(struct sta_info **sta)
418 struct ieee80211_local *local = (*sta)->local;
419 struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
420 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
421 DECLARE_MAC_BUF(mbuf);
424 * pull caller's reference if we're already gone.
426 if (sta_info_hash_del(local, *sta)) {
432 ieee80211_key_free((*sta)->key);
433 WARN_ON((*sta)->key);
436 list_del(&(*sta)->list);
438 if (test_and_clear_sta_flags(*sta, WLAN_STA_PS)) {
440 atomic_dec(&sdata->bss->num_sta_ps);
441 __sta_info_clear_tim_bit(sdata->bss, *sta);
446 if (local->ops->sta_notify) {
447 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
448 sdata = sdata->u.vlan.ap;
450 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
451 STA_NOTIFY_REMOVE, (*sta)->addr);
454 if (ieee80211_vif_is_mesh(&sdata->vif)) {
455 mesh_accept_plinks_update(sdata);
456 #ifdef CONFIG_MAC80211_MESH
457 del_timer(&(*sta)->plink_timer);
461 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
462 printk(KERN_DEBUG "%s: Removed STA %s\n",
463 wiphy_name(local->hw.wiphy), print_mac(mbuf, (*sta)->addr));
464 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
467 * Finally, pull caller's reference if the STA is pinned by the
468 * task that is adding the debugfs entries. In that case, we
469 * leave the STA "to be freed".
471 * The rules are not trivial, but not too complex either:
472 * (1) pin_status is only modified under the sta_lock
473 * (2) STAs may only be pinned under the RTNL so that
474 * sta_info_flush() is guaranteed to actually destroy
475 * all STAs that are active for a given interface, this
476 * is required for correctness because otherwise we
477 * could notify a driver that an interface is going
478 * away and only after that (!) notify it about a STA
479 * on that interface going away.
480 * (3) sta_info_debugfs_add_work() will set the status
481 * to PINNED when it found an item that needs a new
482 * debugfs directory created. In that case, that item
483 * must not be freed although all *RCU* users are done
484 * with it. Hence, we tell the caller of _unlink()
485 * that the item is already gone (as can happen when
486 * two tasks try to unlink/destroy at the same time)
487 * (4) We set the pin_status to DESTROY here when we
489 * (5) sta_info_debugfs_add_work() will reset the pin_status
490 * from PINNED to NORMAL when it is done with the item,
491 * but will check for DESTROY before resetting it in
492 * which case it will free the item.
494 if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
495 (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
501 void sta_info_unlink(struct sta_info **sta)
503 struct ieee80211_local *local = (*sta)->local;
506 spin_lock_irqsave(&local->sta_lock, flags);
507 __sta_info_unlink(sta);
508 spin_unlock_irqrestore(&local->sta_lock, flags);
511 static inline int sta_info_buffer_expired(struct ieee80211_local *local,
512 struct sta_info *sta,
515 struct ieee80211_tx_info *info;
521 info = IEEE80211_SKB_CB(skb);
523 /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
524 timeout = (sta->listen_interval * local->hw.conf.beacon_int * 32 /
526 if (timeout < STA_TX_BUFFER_EXPIRE)
527 timeout = STA_TX_BUFFER_EXPIRE;
528 return time_after(jiffies, info->control.jiffies + timeout);
532 static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
533 struct sta_info *sta)
537 struct ieee80211_sub_if_data *sdata;
538 DECLARE_MAC_BUF(mac);
540 if (skb_queue_empty(&sta->ps_tx_buf))
544 spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
545 skb = skb_peek(&sta->ps_tx_buf);
546 if (sta_info_buffer_expired(local, sta, skb))
547 skb = __skb_dequeue(&sta->ps_tx_buf);
550 spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
556 local->total_ps_buffered--;
557 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
558 printk(KERN_DEBUG "Buffered frame expired (STA "
559 "%s)\n", print_mac(mac, sta->addr));
563 if (skb_queue_empty(&sta->ps_tx_buf))
564 sta_info_clear_tim_bit(sta);
569 static void sta_info_cleanup(unsigned long data)
571 struct ieee80211_local *local = (struct ieee80211_local *) data;
572 struct sta_info *sta;
575 list_for_each_entry_rcu(sta, &local->sta_list, list)
576 sta_info_cleanup_expire_buffered(local, sta);
579 local->sta_cleanup.expires =
580 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
581 add_timer(&local->sta_cleanup);
584 #ifdef CONFIG_MAC80211_DEBUGFS
586 * See comment in __sta_info_unlink,
587 * caller must hold local->sta_lock.
589 static void __sta_info_pin(struct sta_info *sta)
591 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
592 sta->pin_status = STA_INFO_PIN_STAT_PINNED;
596 * See comment in __sta_info_unlink, returns sta if it
597 * needs to be destroyed.
599 static struct sta_info *__sta_info_unpin(struct sta_info *sta)
601 struct sta_info *ret = NULL;
604 spin_lock_irqsave(&sta->local->sta_lock, flags);
605 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
606 sta->pin_status != STA_INFO_PIN_STAT_PINNED);
607 if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
609 sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
610 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
615 static void sta_info_debugfs_add_work(struct work_struct *work)
617 struct ieee80211_local *local =
618 container_of(work, struct ieee80211_local, sta_debugfs_add);
619 struct sta_info *sta, *tmp;
622 /* We need to keep the RTNL across the whole pinned status. */
627 spin_lock_irqsave(&local->sta_lock, flags);
628 list_for_each_entry(tmp, &local->sta_list, list) {
629 if (!tmp->debugfs.dir) {
635 spin_unlock_irqrestore(&local->sta_lock, flags);
640 ieee80211_sta_debugfs_add(sta);
641 rate_control_add_sta_debugfs(sta);
643 sta = __sta_info_unpin(sta);
644 sta_info_destroy(sta);
650 static void __ieee80211_run_pending_flush(struct ieee80211_local *local)
652 struct sta_info *sta;
657 spin_lock_irqsave(&local->sta_lock, flags);
658 while (!list_empty(&local->sta_flush_list)) {
659 sta = list_first_entry(&local->sta_flush_list,
660 struct sta_info, list);
661 list_del(&sta->list);
662 spin_unlock_irqrestore(&local->sta_lock, flags);
663 sta_info_destroy(sta);
664 spin_lock_irqsave(&local->sta_lock, flags);
666 spin_unlock_irqrestore(&local->sta_lock, flags);
669 static void ieee80211_sta_flush_work(struct work_struct *work)
671 struct ieee80211_local *local =
672 container_of(work, struct ieee80211_local, sta_flush_work);
675 __ieee80211_run_pending_flush(local);
679 void sta_info_init(struct ieee80211_local *local)
681 spin_lock_init(&local->sta_lock);
682 INIT_LIST_HEAD(&local->sta_list);
683 INIT_LIST_HEAD(&local->sta_flush_list);
684 INIT_WORK(&local->sta_flush_work, ieee80211_sta_flush_work);
686 setup_timer(&local->sta_cleanup, sta_info_cleanup,
687 (unsigned long)local);
688 local->sta_cleanup.expires =
689 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
691 #ifdef CONFIG_MAC80211_DEBUGFS
692 INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
696 int sta_info_start(struct ieee80211_local *local)
698 add_timer(&local->sta_cleanup);
702 void sta_info_stop(struct ieee80211_local *local)
704 del_timer(&local->sta_cleanup);
705 cancel_work_sync(&local->sta_flush_work);
706 #ifdef CONFIG_MAC80211_DEBUGFS
708 * Make sure the debugfs adding work isn't pending after this
709 * because we're about to be destroyed. It doesn't matter
710 * whether it ran or not since we're going to flush all STAs
713 cancel_work_sync(&local->sta_debugfs_add);
717 sta_info_flush(local, NULL);
718 __ieee80211_run_pending_flush(local);
723 * sta_info_flush - flush matching STA entries from the STA table
725 * Returns the number of removed STA entries.
727 * @local: local interface data
728 * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
730 int sta_info_flush(struct ieee80211_local *local,
731 struct ieee80211_sub_if_data *sdata)
733 struct sta_info *sta, *tmp;
741 spin_lock_irqsave(&local->sta_lock, flags);
742 list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
743 if (!sdata || sdata == sta->sdata) {
744 __sta_info_unlink(&sta);
746 list_add_tail(&sta->list, &tmp_list);
751 spin_unlock_irqrestore(&local->sta_lock, flags);
753 list_for_each_entry_safe(sta, tmp, &tmp_list, list)
754 sta_info_destroy(sta);
760 * sta_info_flush_delayed - flush matching STA entries from the STA table
762 * This function unlinks all stations for a given interface and queues
763 * them for freeing. Note that the workqueue function scheduled here has
764 * to run before any new keys can be added to the system to avoid set_key()
765 * callback ordering issues.
767 * @sdata: the interface
769 void sta_info_flush_delayed(struct ieee80211_sub_if_data *sdata)
771 struct ieee80211_local *local = sdata->local;
772 struct sta_info *sta, *tmp;
776 spin_lock_irqsave(&local->sta_lock, flags);
777 list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
778 if (sdata == sta->sdata) {
779 __sta_info_unlink(&sta);
781 list_add_tail(&sta->list,
782 &local->sta_flush_list);
788 schedule_work(&local->sta_flush_work);
789 spin_unlock_irqrestore(&local->sta_lock, flags);