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 "driver-ops.h"
25 #include "debugfs_sta.h"
29 * DOC: STA information lifetime rules
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.
35 * Upon allocating a STA info structure with sta_info_alloc(), the caller owns
36 * that structure. It must then either destroy it using sta_info_destroy()
37 * (which is pretty useless) or insert it into the hash table using
38 * sta_info_insert() which demotes the reference from ownership to a regular
39 * RCU-protected reference; if the function is called without protection by an
40 * RCU critical section the reference is instantly invalidated. Note that the
41 * caller may not do much with the STA info before inserting it, in particular,
42 * it may not start any mesh peer link management or add encryption keys.
44 * When the insertion fails (sta_info_insert()) returns non-zero), the
45 * structure will have been freed by sta_info_insert()!
47 * Because there are debugfs entries for each station, and adding those
48 * must be able to sleep, it is also possible to "pin" a station entry,
49 * that means it can be removed from the hash table but not be freed.
50 * See the comment in __sta_info_unlink() for more information, this is
51 * an internal capability only.
53 * In order to remove a STA info structure, the caller needs to first
54 * unlink it (sta_info_unlink()) from the list and hash tables and
55 * then destroy it; sta_info_destroy() will wait for an RCU grace period
56 * to elapse before actually freeing it. Due to the pinning and the
57 * possibility of multiple callers trying to remove the same STA info at
58 * the same time, sta_info_unlink() can clear the STA info pointer it is
59 * passed to indicate that the STA info is owned 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().
65 * In all other cases, there is no concept of ownership on a STA entry,
66 * each structure is owned by the global hash table/list until it is
67 * removed. All users of the structure need to be RCU protected so that
68 * the structure won't be freed before they are done using it.
71 /* Caller must hold local->sta_lock */
72 static int sta_info_hash_del(struct ieee80211_local *local,
77 s = local->sta_hash[STA_HASH(sta->sta.addr)];
81 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->sta.addr)],
86 while (s->hnext && s->hnext != sta)
89 rcu_assign_pointer(s->hnext, sta->hnext);
96 /* protected by RCU */
97 struct sta_info *sta_info_get(struct ieee80211_local *local, const u8 *addr)
101 sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
103 if (memcmp(sta->sta.addr, addr, ETH_ALEN) == 0)
105 sta = rcu_dereference(sta->hnext);
110 struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx,
111 struct net_device *dev)
113 struct sta_info *sta;
116 list_for_each_entry_rcu(sta, &local->sta_list, list) {
117 if (dev && dev != sta->sdata->dev)
130 * __sta_info_free - internal STA free helper
132 * @local: pointer to the global information
133 * @sta: STA info to free
135 * This function must undo everything done by sta_info_alloc()
136 * that may happen before sta_info_insert().
138 static void __sta_info_free(struct ieee80211_local *local,
139 struct sta_info *sta)
141 rate_control_free_sta(sta);
142 rate_control_put(sta->rate_ctrl);
144 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
145 printk(KERN_DEBUG "%s: Destroyed STA %pM\n",
146 wiphy_name(local->hw.wiphy), sta->sta.addr);
147 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
152 void sta_info_destroy(struct sta_info *sta)
154 struct ieee80211_local *local;
165 rate_control_remove_sta_debugfs(sta);
166 ieee80211_sta_debugfs_remove(sta);
168 #ifdef CONFIG_MAC80211_MESH
169 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
170 mesh_plink_deactivate(sta);
174 * We have only unlinked the key, and actually destroying it
175 * may mean it is removed from hardware which requires that
176 * the key->sta pointer is still valid, so flush the key todo
179 * ieee80211_key_todo() will synchronize_rcu() so after this
180 * nothing can reference this sta struct any more.
182 ieee80211_key_todo();
184 #ifdef CONFIG_MAC80211_MESH
185 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
186 del_timer_sync(&sta->plink_timer);
189 while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
190 local->total_ps_buffered--;
191 dev_kfree_skb_any(skb);
194 while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
195 dev_kfree_skb_any(skb);
197 for (i = 0; i < STA_TID_NUM; i++) {
198 struct tid_ampdu_rx *tid_rx;
199 struct tid_ampdu_tx *tid_tx;
201 spin_lock_bh(&sta->lock);
202 tid_rx = sta->ampdu_mlme.tid_rx[i];
203 /* Make sure timer won't free the tid_rx struct, see below */
205 tid_rx->shutdown = true;
207 spin_unlock_bh(&sta->lock);
210 * Outside spinlock - shutdown is true now so that the timer
211 * won't free tid_rx, we have to do that now. Can't let the
212 * timer do it because we have to sync the timer outside the
213 * lock that it takes itself.
216 del_timer_sync(&tid_rx->session_timer);
221 * No need to do such complications for TX agg sessions, the
222 * path leading to freeing the tid_tx struct goes via a call
223 * from the driver, and thus needs to look up the sta struct
224 * again, which cannot be found when we get here. Hence, we
225 * just need to delete the timer and free the aggregation
226 * info; we won't be telling the peer about it then but that
227 * doesn't matter if we're not talking to it again anyway.
229 tid_tx = sta->ampdu_mlme.tid_tx[i];
231 del_timer_sync(&tid_tx->addba_resp_timer);
233 * STA removed while aggregation session being
234 * started? Bit odd, but purge frames anyway.
236 skb_queue_purge(&tid_tx->pending);
241 __sta_info_free(local, sta);
245 /* Caller must hold local->sta_lock */
246 static void sta_info_hash_add(struct ieee80211_local *local,
247 struct sta_info *sta)
249 sta->hnext = local->sta_hash[STA_HASH(sta->sta.addr)];
250 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->sta.addr)], sta);
253 struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
256 struct ieee80211_local *local = sdata->local;
257 struct sta_info *sta;
260 sta = kzalloc(sizeof(*sta) + local->hw.sta_data_size, gfp);
264 spin_lock_init(&sta->lock);
265 spin_lock_init(&sta->flaglock);
267 memcpy(sta->sta.addr, addr, ETH_ALEN);
271 sta->rate_ctrl = rate_control_get(local->rate_ctrl);
272 sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
274 if (!sta->rate_ctrl_priv) {
275 rate_control_put(sta->rate_ctrl);
280 for (i = 0; i < STA_TID_NUM; i++) {
281 /* timer_to_tid must be initialized with identity mapping to
282 * enable session_timer's data differentiation. refer to
283 * sta_rx_agg_session_timer_expired for useage */
284 sta->timer_to_tid[i] = i;
286 sta->ampdu_mlme.tid_state_rx[i] = HT_AGG_STATE_IDLE;
287 sta->ampdu_mlme.tid_rx[i] = NULL;
289 sta->ampdu_mlme.tid_state_tx[i] = HT_AGG_STATE_IDLE;
290 sta->ampdu_mlme.tid_tx[i] = NULL;
291 sta->ampdu_mlme.addba_req_num[i] = 0;
293 skb_queue_head_init(&sta->ps_tx_buf);
294 skb_queue_head_init(&sta->tx_filtered);
296 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
297 printk(KERN_DEBUG "%s: Allocated STA %pM\n",
298 wiphy_name(local->hw.wiphy), sta->sta.addr);
299 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
301 #ifdef CONFIG_MAC80211_MESH
302 sta->plink_state = PLINK_LISTEN;
303 init_timer(&sta->plink_timer);
309 int sta_info_insert(struct sta_info *sta)
311 struct ieee80211_local *local = sta->local;
312 struct ieee80211_sub_if_data *sdata = sta->sdata;
317 * Can't be a WARN_ON because it can be triggered through a race:
318 * something inserts a STA (on one CPU) without holding the RTNL
319 * and another CPU turns off the net device.
321 if (unlikely(!netif_running(sdata->dev))) {
326 if (WARN_ON(compare_ether_addr(sta->sta.addr, sdata->dev->dev_addr) == 0 ||
327 is_multicast_ether_addr(sta->sta.addr))) {
332 spin_lock_irqsave(&local->sta_lock, flags);
333 /* check if STA exists already */
334 if (sta_info_get(local, sta->sta.addr)) {
335 spin_unlock_irqrestore(&local->sta_lock, flags);
339 list_add(&sta->list, &local->sta_list);
341 sta_info_hash_add(local, sta);
344 if (local->ops->sta_notify) {
345 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
346 sdata = container_of(sdata->bss,
347 struct ieee80211_sub_if_data,
350 drv_sta_notify(local, &sdata->vif, STA_NOTIFY_ADD, &sta->sta);
353 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
354 printk(KERN_DEBUG "%s: Inserted STA %pM\n",
355 wiphy_name(local->hw.wiphy), sta->sta.addr);
356 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
358 spin_unlock_irqrestore(&local->sta_lock, flags);
360 #ifdef CONFIG_MAC80211_DEBUGFS
362 * Debugfs entry adding might sleep, so schedule process
363 * context task for adding entry for STAs that do not yet
365 * NOTE: due to auto-freeing semantics this may only be done
366 * if the insertion is successful!
368 schedule_work(&local->sta_debugfs_add);
371 if (ieee80211_vif_is_mesh(&sdata->vif))
372 mesh_accept_plinks_update(sdata);
377 __sta_info_free(local, sta);
381 static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
384 * This format has been mandated by the IEEE specifications,
385 * so this line may not be changed to use the __set_bit() format.
387 bss->tim[aid / 8] |= (1 << (aid % 8));
390 static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
393 * This format has been mandated by the IEEE specifications,
394 * so this line may not be changed to use the __clear_bit() format.
396 bss->tim[aid / 8] &= ~(1 << (aid % 8));
399 static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
400 struct sta_info *sta)
404 __bss_tim_set(bss, sta->sta.aid);
406 if (sta->local->ops->set_tim) {
407 sta->local->tim_in_locked_section = true;
408 drv_set_tim(sta->local, &sta->sta, true);
409 sta->local->tim_in_locked_section = false;
413 void sta_info_set_tim_bit(struct sta_info *sta)
417 BUG_ON(!sta->sdata->bss);
419 spin_lock_irqsave(&sta->local->sta_lock, flags);
420 __sta_info_set_tim_bit(sta->sdata->bss, sta);
421 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
424 static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
425 struct sta_info *sta)
429 __bss_tim_clear(bss, sta->sta.aid);
431 if (sta->local->ops->set_tim) {
432 sta->local->tim_in_locked_section = true;
433 drv_set_tim(sta->local, &sta->sta, false);
434 sta->local->tim_in_locked_section = false;
438 void sta_info_clear_tim_bit(struct sta_info *sta)
442 BUG_ON(!sta->sdata->bss);
444 spin_lock_irqsave(&sta->local->sta_lock, flags);
445 __sta_info_clear_tim_bit(sta->sdata->bss, sta);
446 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
449 static void __sta_info_unlink(struct sta_info **sta)
451 struct ieee80211_local *local = (*sta)->local;
452 struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
454 * pull caller's reference if we're already gone.
456 if (sta_info_hash_del(local, *sta)) {
462 ieee80211_key_free((*sta)->key);
463 WARN_ON((*sta)->key);
466 list_del(&(*sta)->list);
468 if (test_and_clear_sta_flags(*sta, WLAN_STA_PS)) {
471 atomic_dec(&sdata->bss->num_sta_ps);
472 __sta_info_clear_tim_bit(sdata->bss, *sta);
477 if (local->ops->sta_notify) {
478 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
479 sdata = container_of(sdata->bss,
480 struct ieee80211_sub_if_data,
483 drv_sta_notify(local, &sdata->vif, STA_NOTIFY_REMOVE,
487 if (ieee80211_vif_is_mesh(&sdata->vif)) {
488 mesh_accept_plinks_update(sdata);
489 #ifdef CONFIG_MAC80211_MESH
490 del_timer(&(*sta)->plink_timer);
494 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
495 printk(KERN_DEBUG "%s: Removed STA %pM\n",
496 wiphy_name(local->hw.wiphy), (*sta)->sta.addr);
497 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
500 * Finally, pull caller's reference if the STA is pinned by the
501 * task that is adding the debugfs entries. In that case, we
502 * leave the STA "to be freed".
504 * The rules are not trivial, but not too complex either:
505 * (1) pin_status is only modified under the sta_lock
506 * (2) STAs may only be pinned under the RTNL so that
507 * sta_info_flush() is guaranteed to actually destroy
508 * all STAs that are active for a given interface, this
509 * is required for correctness because otherwise we
510 * could notify a driver that an interface is going
511 * away and only after that (!) notify it about a STA
512 * on that interface going away.
513 * (3) sta_info_debugfs_add_work() will set the status
514 * to PINNED when it found an item that needs a new
515 * debugfs directory created. In that case, that item
516 * must not be freed although all *RCU* users are done
517 * with it. Hence, we tell the caller of _unlink()
518 * that the item is already gone (as can happen when
519 * two tasks try to unlink/destroy at the same time)
520 * (4) We set the pin_status to DESTROY here when we
522 * (5) sta_info_debugfs_add_work() will reset the pin_status
523 * from PINNED to NORMAL when it is done with the item,
524 * but will check for DESTROY before resetting it in
525 * which case it will free the item.
527 if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
528 (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
534 void sta_info_unlink(struct sta_info **sta)
536 struct ieee80211_local *local = (*sta)->local;
539 spin_lock_irqsave(&local->sta_lock, flags);
540 __sta_info_unlink(sta);
541 spin_unlock_irqrestore(&local->sta_lock, flags);
544 static int sta_info_buffer_expired(struct sta_info *sta,
547 struct ieee80211_tx_info *info;
553 info = IEEE80211_SKB_CB(skb);
555 /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
556 timeout = (sta->listen_interval *
557 sta->sdata->vif.bss_conf.beacon_int *
559 if (timeout < STA_TX_BUFFER_EXPIRE)
560 timeout = STA_TX_BUFFER_EXPIRE;
561 return time_after(jiffies, info->control.jiffies + timeout);
565 static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
566 struct sta_info *sta)
570 struct ieee80211_sub_if_data *sdata;
572 if (skb_queue_empty(&sta->ps_tx_buf))
576 spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
577 skb = skb_peek(&sta->ps_tx_buf);
578 if (sta_info_buffer_expired(sta, skb))
579 skb = __skb_dequeue(&sta->ps_tx_buf);
582 spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
588 local->total_ps_buffered--;
589 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
590 printk(KERN_DEBUG "Buffered frame expired (STA %pM)\n",
595 if (skb_queue_empty(&sta->ps_tx_buf))
596 sta_info_clear_tim_bit(sta);
601 static void sta_info_cleanup(unsigned long data)
603 struct ieee80211_local *local = (struct ieee80211_local *) data;
604 struct sta_info *sta;
607 list_for_each_entry_rcu(sta, &local->sta_list, list)
608 sta_info_cleanup_expire_buffered(local, sta);
611 local->sta_cleanup.expires =
612 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
613 add_timer(&local->sta_cleanup);
616 #ifdef CONFIG_MAC80211_DEBUGFS
618 * See comment in __sta_info_unlink,
619 * caller must hold local->sta_lock.
621 static void __sta_info_pin(struct sta_info *sta)
623 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
624 sta->pin_status = STA_INFO_PIN_STAT_PINNED;
628 * See comment in __sta_info_unlink, returns sta if it
629 * needs to be destroyed.
631 static struct sta_info *__sta_info_unpin(struct sta_info *sta)
633 struct sta_info *ret = NULL;
636 spin_lock_irqsave(&sta->local->sta_lock, flags);
637 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
638 sta->pin_status != STA_INFO_PIN_STAT_PINNED);
639 if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
641 sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
642 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
647 static void sta_info_debugfs_add_work(struct work_struct *work)
649 struct ieee80211_local *local =
650 container_of(work, struct ieee80211_local, sta_debugfs_add);
651 struct sta_info *sta, *tmp;
654 /* We need to keep the RTNL across the whole pinned status. */
659 spin_lock_irqsave(&local->sta_lock, flags);
660 list_for_each_entry(tmp, &local->sta_list, list) {
662 * debugfs.add_has_run will be set by
663 * ieee80211_sta_debugfs_add regardless
664 * of what else it does.
666 if (!tmp->debugfs.add_has_run) {
672 spin_unlock_irqrestore(&local->sta_lock, flags);
677 ieee80211_sta_debugfs_add(sta);
678 rate_control_add_sta_debugfs(sta);
680 sta = __sta_info_unpin(sta);
681 sta_info_destroy(sta);
687 void sta_info_init(struct ieee80211_local *local)
689 spin_lock_init(&local->sta_lock);
690 INIT_LIST_HEAD(&local->sta_list);
692 setup_timer(&local->sta_cleanup, sta_info_cleanup,
693 (unsigned long)local);
694 local->sta_cleanup.expires =
695 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
697 #ifdef CONFIG_MAC80211_DEBUGFS
698 INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
702 int sta_info_start(struct ieee80211_local *local)
704 add_timer(&local->sta_cleanup);
708 void sta_info_stop(struct ieee80211_local *local)
710 del_timer(&local->sta_cleanup);
711 #ifdef CONFIG_MAC80211_DEBUGFS
713 * Make sure the debugfs adding work isn't pending after this
714 * because we're about to be destroyed. It doesn't matter
715 * whether it ran or not since we're going to flush all STAs
718 cancel_work_sync(&local->sta_debugfs_add);
721 sta_info_flush(local, NULL);
725 * sta_info_flush - flush matching STA entries from the STA table
727 * Returns the number of removed STA entries.
729 * @local: local interface data
730 * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
732 int sta_info_flush(struct ieee80211_local *local,
733 struct ieee80211_sub_if_data *sdata)
735 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);
760 void ieee80211_sta_expire(struct ieee80211_sub_if_data *sdata,
761 unsigned long exp_time)
763 struct ieee80211_local *local = sdata->local;
764 struct sta_info *sta, *tmp;
768 spin_lock_irqsave(&local->sta_lock, flags);
769 list_for_each_entry_safe(sta, tmp, &local->sta_list, list)
770 if (time_after(jiffies, sta->last_rx + exp_time)) {
771 #ifdef CONFIG_MAC80211_IBSS_DEBUG
772 printk(KERN_DEBUG "%s: expiring inactive STA %pM\n",
773 sdata->dev->name, sta->sta.addr);
775 __sta_info_unlink(&sta);
777 list_add(&sta->list, &tmp_list);
779 spin_unlock_irqrestore(&local->sta_lock, flags);
781 list_for_each_entry_safe(sta, tmp, &tmp_list, list)
782 sta_info_destroy(sta);
785 struct ieee80211_sta *ieee80211_find_sta(struct ieee80211_hw *hw,
788 struct sta_info *sta = sta_info_get(hw_to_local(hw), addr);
794 EXPORT_SYMBOL(ieee80211_find_sta);