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 * @local: pointer to the global information
139 * @sta: STA info to free
141 * This function must undo everything done by sta_info_alloc()
142 * that may happen before sta_info_insert().
144 static void __sta_info_free(struct ieee80211_local *local,
145 struct sta_info *sta)
147 DECLARE_MAC_BUF(mbuf);
149 rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
150 rate_control_put(sta->rate_ctrl);
152 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
153 printk(KERN_DEBUG "%s: Destroyed STA %s\n",
154 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
155 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
160 void sta_info_destroy(struct sta_info *sta)
162 struct ieee80211_local *local;
173 rate_control_remove_sta_debugfs(sta);
174 ieee80211_sta_debugfs_remove(sta);
176 #ifdef CONFIG_MAC80211_MESH
177 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
178 mesh_plink_deactivate(sta);
182 * We have only unlinked the key, and actually destroying it
183 * may mean it is removed from hardware which requires that
184 * the key->sta pointer is still valid, so flush the key todo
187 * ieee80211_key_todo() will synchronize_rcu() so after this
188 * nothing can reference this sta struct any more.
190 ieee80211_key_todo();
192 #ifdef CONFIG_MAC80211_MESH
193 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
194 del_timer_sync(&sta->plink_timer);
197 while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
198 local->total_ps_buffered--;
199 dev_kfree_skb_any(skb);
202 while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
203 dev_kfree_skb_any(skb);
205 for (i = 0; i < STA_TID_NUM; i++) {
206 spin_lock_bh(&sta->lock);
207 if (sta->ampdu_mlme.tid_rx[i])
208 del_timer_sync(&sta->ampdu_mlme.tid_rx[i]->session_timer);
209 if (sta->ampdu_mlme.tid_tx[i])
210 del_timer_sync(&sta->ampdu_mlme.tid_tx[i]->addba_resp_timer);
211 spin_unlock_bh(&sta->lock);
214 __sta_info_free(local, sta);
218 /* Caller must hold local->sta_lock */
219 static void sta_info_hash_add(struct ieee80211_local *local,
220 struct sta_info *sta)
222 sta->hnext = local->sta_hash[STA_HASH(sta->addr)];
223 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], sta);
226 struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
229 struct ieee80211_local *local = sdata->local;
230 struct sta_info *sta;
232 DECLARE_MAC_BUF(mbuf);
234 sta = kzalloc(sizeof(*sta), gfp);
238 spin_lock_init(&sta->lock);
239 spin_lock_init(&sta->flaglock);
241 memcpy(sta->addr, addr, ETH_ALEN);
245 sta->rate_ctrl = rate_control_get(local->rate_ctrl);
246 sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
248 if (!sta->rate_ctrl_priv) {
249 rate_control_put(sta->rate_ctrl);
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] = ieee80211_num_queues(&local->hw);
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 init_timer(&sta->plink_timer);
285 int sta_info_insert(struct sta_info *sta)
287 struct ieee80211_local *local = sta->local;
288 struct ieee80211_sub_if_data *sdata = sta->sdata;
291 DECLARE_MAC_BUF(mac);
294 * Can't be a WARN_ON because it can be triggered through a race:
295 * something inserts a STA (on one CPU) without holding the RTNL
296 * and another CPU turns off the net device.
298 if (unlikely(!netif_running(sdata->dev))) {
303 if (WARN_ON(compare_ether_addr(sta->addr, sdata->dev->dev_addr) == 0 ||
304 is_multicast_ether_addr(sta->addr))) {
309 spin_lock_irqsave(&local->sta_lock, flags);
310 /* check if STA exists already */
311 if (__sta_info_find(local, sta->addr)) {
312 spin_unlock_irqrestore(&local->sta_lock, flags);
316 list_add(&sta->list, &local->sta_list);
318 sta_info_hash_add(local, sta);
321 if (local->ops->sta_notify) {
322 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
323 sdata = sdata->u.vlan.ap;
325 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
326 STA_NOTIFY_ADD, sta->addr);
329 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
330 printk(KERN_DEBUG "%s: Inserted STA %s\n",
331 wiphy_name(local->hw.wiphy), print_mac(mac, sta->addr));
332 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
334 spin_unlock_irqrestore(&local->sta_lock, flags);
336 #ifdef CONFIG_MAC80211_DEBUGFS
338 * Debugfs entry adding might sleep, so schedule process
339 * context task for adding entry for STAs that do not yet
341 * NOTE: due to auto-freeing semantics this may only be done
342 * if the insertion is successful!
344 schedule_work(&local->sta_debugfs_add);
347 if (ieee80211_vif_is_mesh(&sdata->vif))
348 mesh_accept_plinks_update(sdata);
353 __sta_info_free(local, sta);
357 static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
360 * This format has been mandated by the IEEE specifications,
361 * so this line may not be changed to use the __set_bit() format.
363 bss->tim[aid / 8] |= (1 << (aid % 8));
366 static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
369 * This format has been mandated by the IEEE specifications,
370 * so this line may not be changed to use the __clear_bit() format.
372 bss->tim[aid / 8] &= ~(1 << (aid % 8));
375 static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
376 struct sta_info *sta)
379 __bss_tim_set(bss, sta->aid);
380 if (sta->local->ops->set_tim) {
381 sta->local->tim_in_locked_section = true;
382 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 1);
383 sta->local->tim_in_locked_section = false;
387 void sta_info_set_tim_bit(struct sta_info *sta)
391 spin_lock_irqsave(&sta->local->sta_lock, flags);
392 __sta_info_set_tim_bit(sta->sdata->bss, sta);
393 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
396 static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
397 struct sta_info *sta)
400 __bss_tim_clear(bss, sta->aid);
401 if (sta->local->ops->set_tim) {
402 sta->local->tim_in_locked_section = true;
403 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 0);
404 sta->local->tim_in_locked_section = false;
408 void sta_info_clear_tim_bit(struct sta_info *sta)
412 spin_lock_irqsave(&sta->local->sta_lock, flags);
413 __sta_info_clear_tim_bit(sta->sdata->bss, sta);
414 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
417 void __sta_info_unlink(struct sta_info **sta)
419 struct ieee80211_local *local = (*sta)->local;
420 struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
421 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
422 DECLARE_MAC_BUF(mbuf);
425 * pull caller's reference if we're already gone.
427 if (sta_info_hash_del(local, *sta)) {
433 ieee80211_key_free((*sta)->key);
434 WARN_ON((*sta)->key);
437 list_del(&(*sta)->list);
439 if (test_and_clear_sta_flags(*sta, WLAN_STA_PS)) {
441 atomic_dec(&sdata->bss->num_sta_ps);
442 __sta_info_clear_tim_bit(sdata->bss, *sta);
447 if (local->ops->sta_notify) {
448 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
449 sdata = sdata->u.vlan.ap;
451 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
452 STA_NOTIFY_REMOVE, (*sta)->addr);
455 if (ieee80211_vif_is_mesh(&sdata->vif)) {
456 mesh_accept_plinks_update(sdata);
457 #ifdef CONFIG_MAC80211_MESH
458 del_timer(&(*sta)->plink_timer);
462 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
463 printk(KERN_DEBUG "%s: Removed STA %s\n",
464 wiphy_name(local->hw.wiphy), print_mac(mbuf, (*sta)->addr));
465 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
468 * Finally, pull caller's reference if the STA is pinned by the
469 * task that is adding the debugfs entries. In that case, we
470 * leave the STA "to be freed".
472 * The rules are not trivial, but not too complex either:
473 * (1) pin_status is only modified under the sta_lock
474 * (2) STAs may only be pinned under the RTNL so that
475 * sta_info_flush() is guaranteed to actually destroy
476 * all STAs that are active for a given interface, this
477 * is required for correctness because otherwise we
478 * could notify a driver that an interface is going
479 * away and only after that (!) notify it about a STA
480 * on that interface going away.
481 * (3) sta_info_debugfs_add_work() will set the status
482 * to PINNED when it found an item that needs a new
483 * debugfs directory created. In that case, that item
484 * must not be freed although all *RCU* users are done
485 * with it. Hence, we tell the caller of _unlink()
486 * that the item is already gone (as can happen when
487 * two tasks try to unlink/destroy at the same time)
488 * (4) We set the pin_status to DESTROY here when we
490 * (5) sta_info_debugfs_add_work() will reset the pin_status
491 * from PINNED to NORMAL when it is done with the item,
492 * but will check for DESTROY before resetting it in
493 * which case it will free the item.
495 if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
496 (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
502 void sta_info_unlink(struct sta_info **sta)
504 struct ieee80211_local *local = (*sta)->local;
507 spin_lock_irqsave(&local->sta_lock, flags);
508 __sta_info_unlink(sta);
509 spin_unlock_irqrestore(&local->sta_lock, flags);
512 static inline int sta_info_buffer_expired(struct ieee80211_local *local,
513 struct sta_info *sta,
516 struct ieee80211_tx_info *info;
522 info = IEEE80211_SKB_CB(skb);
524 /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
525 timeout = (sta->listen_interval * local->hw.conf.beacon_int * 32 /
527 if (timeout < STA_TX_BUFFER_EXPIRE)
528 timeout = STA_TX_BUFFER_EXPIRE;
529 return time_after(jiffies, info->control.jiffies + timeout);
533 static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
534 struct sta_info *sta)
538 struct ieee80211_sub_if_data *sdata;
539 DECLARE_MAC_BUF(mac);
541 if (skb_queue_empty(&sta->ps_tx_buf))
545 spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
546 skb = skb_peek(&sta->ps_tx_buf);
547 if (sta_info_buffer_expired(local, sta, skb))
548 skb = __skb_dequeue(&sta->ps_tx_buf);
551 spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
557 local->total_ps_buffered--;
558 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
559 printk(KERN_DEBUG "Buffered frame expired (STA "
560 "%s)\n", print_mac(mac, sta->addr));
564 if (skb_queue_empty(&sta->ps_tx_buf))
565 sta_info_clear_tim_bit(sta);
570 static void sta_info_cleanup(unsigned long data)
572 struct ieee80211_local *local = (struct ieee80211_local *) data;
573 struct sta_info *sta;
576 list_for_each_entry_rcu(sta, &local->sta_list, list)
577 sta_info_cleanup_expire_buffered(local, sta);
580 local->sta_cleanup.expires =
581 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
582 add_timer(&local->sta_cleanup);
585 #ifdef CONFIG_MAC80211_DEBUGFS
587 * See comment in __sta_info_unlink,
588 * caller must hold local->sta_lock.
590 static void __sta_info_pin(struct sta_info *sta)
592 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
593 sta->pin_status = STA_INFO_PIN_STAT_PINNED;
597 * See comment in __sta_info_unlink, returns sta if it
598 * needs to be destroyed.
600 static struct sta_info *__sta_info_unpin(struct sta_info *sta)
602 struct sta_info *ret = NULL;
605 spin_lock_irqsave(&sta->local->sta_lock, flags);
606 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
607 sta->pin_status != STA_INFO_PIN_STAT_PINNED);
608 if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
610 sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
611 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
616 static void sta_info_debugfs_add_work(struct work_struct *work)
618 struct ieee80211_local *local =
619 container_of(work, struct ieee80211_local, sta_debugfs_add);
620 struct sta_info *sta, *tmp;
623 /* We need to keep the RTNL across the whole pinned status. */
628 spin_lock_irqsave(&local->sta_lock, flags);
629 list_for_each_entry(tmp, &local->sta_list, list) {
630 if (!tmp->debugfs.dir) {
636 spin_unlock_irqrestore(&local->sta_lock, flags);
641 ieee80211_sta_debugfs_add(sta);
642 rate_control_add_sta_debugfs(sta);
644 sta = __sta_info_unpin(sta);
645 sta_info_destroy(sta);
651 static void __ieee80211_run_pending_flush(struct ieee80211_local *local)
653 struct sta_info *sta;
658 spin_lock_irqsave(&local->sta_lock, flags);
659 while (!list_empty(&local->sta_flush_list)) {
660 sta = list_first_entry(&local->sta_flush_list,
661 struct sta_info, list);
662 list_del(&sta->list);
663 spin_unlock_irqrestore(&local->sta_lock, flags);
664 sta_info_destroy(sta);
665 spin_lock_irqsave(&local->sta_lock, flags);
667 spin_unlock_irqrestore(&local->sta_lock, flags);
670 static void ieee80211_sta_flush_work(struct work_struct *work)
672 struct ieee80211_local *local =
673 container_of(work, struct ieee80211_local, sta_flush_work);
676 __ieee80211_run_pending_flush(local);
680 void sta_info_init(struct ieee80211_local *local)
682 spin_lock_init(&local->sta_lock);
683 INIT_LIST_HEAD(&local->sta_list);
684 INIT_LIST_HEAD(&local->sta_flush_list);
685 INIT_WORK(&local->sta_flush_work, ieee80211_sta_flush_work);
687 setup_timer(&local->sta_cleanup, sta_info_cleanup,
688 (unsigned long)local);
689 local->sta_cleanup.expires =
690 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
692 #ifdef CONFIG_MAC80211_DEBUGFS
693 INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
697 int sta_info_start(struct ieee80211_local *local)
699 add_timer(&local->sta_cleanup);
703 void sta_info_stop(struct ieee80211_local *local)
705 del_timer(&local->sta_cleanup);
706 cancel_work_sync(&local->sta_flush_work);
707 #ifdef CONFIG_MAC80211_DEBUGFS
709 * Make sure the debugfs adding work isn't pending after this
710 * because we're about to be destroyed. It doesn't matter
711 * whether it ran or not since we're going to flush all STAs
714 cancel_work_sync(&local->sta_debugfs_add);
718 sta_info_flush(local, NULL);
719 __ieee80211_run_pending_flush(local);
724 * sta_info_flush - flush matching STA entries from the STA table
726 * Returns the number of removed STA entries.
728 * @local: local interface data
729 * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
731 int sta_info_flush(struct ieee80211_local *local,
732 struct ieee80211_sub_if_data *sdata)
734 struct sta_info *sta, *tmp;
742 spin_lock_irqsave(&local->sta_lock, flags);
743 list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
744 if (!sdata || sdata == sta->sdata) {
745 __sta_info_unlink(&sta);
747 list_add_tail(&sta->list, &tmp_list);
752 spin_unlock_irqrestore(&local->sta_lock, flags);
754 list_for_each_entry_safe(sta, tmp, &tmp_list, list)
755 sta_info_destroy(sta);
761 * sta_info_flush_delayed - flush matching STA entries from the STA table
763 * This function unlinks all stations for a given interface and queues
764 * them for freeing. Note that the workqueue function scheduled here has
765 * to run before any new keys can be added to the system to avoid set_key()
766 * callback ordering issues.
768 * @sdata: the interface
770 void sta_info_flush_delayed(struct ieee80211_sub_if_data *sdata)
772 struct ieee80211_local *local = sdata->local;
773 struct sta_info *sta, *tmp;
777 spin_lock_irqsave(&local->sta_lock, flags);
778 list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
779 if (sdata == sta->sdata) {
780 __sta_info_unlink(&sta);
782 list_add_tail(&sta->list,
783 &local->sta_flush_list);
789 schedule_work(&local->sta_flush_work);
790 spin_unlock_irqrestore(&local->sta_lock, flags);