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() or
35 * mesh_plink_alloc(), the caller owns that structure. It must then either
36 * destroy it using sta_info_destroy() (which is pretty useless) or insert
37 * it into the hash table using sta_info_insert() which demotes the reference
38 * from ownership to a regular RCU-protected reference; if the function
39 * is called without protection by an RCU critical section the reference
40 * is instantly invalidated.
42 * Because there are debugfs entries for each station, and adding those
43 * must be able to sleep, it is also possible to "pin" a station entry,
44 * that means it can be removed from the hash table but not be freed.
45 * See the comment in __sta_info_unlink() for more information.
47 * In order to remove a STA info structure, the caller needs to first
48 * unlink it (sta_info_unlink()) from the list and hash tables and
49 * then wait for an RCU synchronisation before it can be freed. Due to
50 * the pinning and the possibility of multiple callers trying to remove
51 * the same STA info at the same time, sta_info_unlink() can clear the
52 * STA info pointer it is passed to indicate that the STA info is owned
53 * by somebody else now.
55 * If sta_info_unlink() did not clear the pointer then the caller owns
56 * the STA info structure now and is responsible of destroying it with
57 * a call to sta_info_destroy(), not before RCU synchronisation, of
58 * course. Note that sta_info_destroy() must be protected by the RTNL.
60 * In all other cases, there is no concept of ownership on a STA entry,
61 * each structure is owned by the global hash table/list until it is
62 * removed. All users of the structure need to be RCU protected so that
63 * the structure won't be freed before they are done using it.
66 /* Caller must hold local->sta_lock */
67 static int sta_info_hash_del(struct ieee80211_local *local,
72 s = local->sta_hash[STA_HASH(sta->addr)];
76 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)],
81 while (s->hnext && s->hnext != sta)
84 rcu_assign_pointer(s->hnext, sta->hnext);
91 /* protected by RCU */
92 static struct sta_info *__sta_info_find(struct ieee80211_local *local,
97 sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
99 if (compare_ether_addr(sta->addr, addr) == 0)
101 sta = rcu_dereference(sta->hnext);
106 struct sta_info *sta_info_get(struct ieee80211_local *local, u8 *addr)
108 return __sta_info_find(local, addr);
110 EXPORT_SYMBOL(sta_info_get);
112 struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx,
113 struct net_device *dev)
115 struct sta_info *sta;
118 list_for_each_entry_rcu(sta, &local->sta_list, list) {
122 } else if (!dev || dev == sta->sdata->dev) {
130 void sta_info_destroy(struct sta_info *sta)
132 struct ieee80211_local *local = sta->local;
135 DECLARE_MAC_BUF(mbuf);
143 rate_control_remove_sta_debugfs(sta);
144 ieee80211_sta_debugfs_remove(sta);
146 #ifdef CONFIG_MAC80211_MESH
147 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
148 mesh_plink_deactivate(sta);
152 * NOTE: This will call synchronize_rcu() internally to
153 * make sure no key references can be in use. We rely on
154 * that here for the mesh code!
156 ieee80211_key_free(sta->key);
159 #ifdef CONFIG_MAC80211_MESH
160 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
161 del_timer_sync(&sta->plink_timer);
164 while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
165 local->total_ps_buffered--;
166 dev_kfree_skb_any(skb);
169 while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
170 dev_kfree_skb_any(skb);
172 for (i = 0; i < STA_TID_NUM; i++) {
173 del_timer_sync(&sta->ampdu_mlme.tid_rx[i].session_timer);
174 del_timer_sync(&sta->ampdu_mlme.tid_tx[i].addba_resp_timer);
176 rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
177 rate_control_put(sta->rate_ctrl);
179 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
180 printk(KERN_DEBUG "%s: Destroyed STA %s\n",
181 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
182 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
188 /* Caller must hold local->sta_lock */
189 static void sta_info_hash_add(struct ieee80211_local *local,
190 struct sta_info *sta)
192 sta->hnext = local->sta_hash[STA_HASH(sta->addr)];
193 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], sta);
196 struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
199 struct ieee80211_local *local = sdata->local;
200 struct sta_info *sta;
202 DECLARE_MAC_BUF(mbuf);
204 sta = kzalloc(sizeof(*sta), gfp);
208 memcpy(sta->addr, addr, ETH_ALEN);
212 sta->rate_ctrl = rate_control_get(local->rate_ctrl);
213 sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
215 if (!sta->rate_ctrl_priv) {
216 rate_control_put(sta->rate_ctrl);
221 spin_lock_init(&sta->ampdu_mlme.ampdu_rx);
222 spin_lock_init(&sta->ampdu_mlme.ampdu_tx);
223 for (i = 0; i < STA_TID_NUM; i++) {
224 /* timer_to_tid must be initialized with identity mapping to
225 * enable session_timer's data differentiation. refer to
226 * sta_rx_agg_session_timer_expired for useage */
227 sta->timer_to_tid[i] = i;
228 /* tid to tx queue: initialize according to HW (0 is valid) */
229 sta->tid_to_tx_q[i] = local->hw.queues;
231 sta->ampdu_mlme.tid_rx[i].session_timer.function =
232 sta_rx_agg_session_timer_expired;
233 sta->ampdu_mlme.tid_rx[i].session_timer.data =
234 (unsigned long)&sta->timer_to_tid[i];
235 init_timer(&sta->ampdu_mlme.tid_rx[i].session_timer);
237 sta->ampdu_mlme.tid_tx[i].addba_resp_timer.function =
238 sta_addba_resp_timer_expired;
239 sta->ampdu_mlme.tid_tx[i].addba_resp_timer.data =
240 (unsigned long)&sta->timer_to_tid[i];
241 init_timer(&sta->ampdu_mlme.tid_tx[i].addba_resp_timer);
243 skb_queue_head_init(&sta->ps_tx_buf);
244 skb_queue_head_init(&sta->tx_filtered);
246 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
247 printk(KERN_DEBUG "%s: Allocated STA %s\n",
248 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
249 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
254 int sta_info_insert(struct sta_info *sta)
256 struct ieee80211_local *local = sta->local;
257 struct ieee80211_sub_if_data *sdata = sta->sdata;
259 DECLARE_MAC_BUF(mac);
261 WARN_ON(!netif_running(sdata->dev));
263 spin_lock_irqsave(&local->sta_lock, flags);
264 /* check if STA exists already */
265 if (__sta_info_find(local, sta->addr)) {
266 spin_unlock_irqrestore(&local->sta_lock, flags);
269 list_add(&sta->list, &local->sta_list);
271 sta_info_hash_add(local, sta);
274 if (local->ops->sta_notify) {
275 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
276 sdata = sdata->u.vlan.ap;
278 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
279 STA_NOTIFY_ADD, sta->addr);
282 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
283 printk(KERN_DEBUG "%s: Inserted STA %s\n",
284 wiphy_name(local->hw.wiphy), print_mac(mac, sta->addr));
285 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
287 spin_unlock_irqrestore(&local->sta_lock, flags);
289 #ifdef CONFIG_MAC80211_DEBUGFS
290 /* debugfs entry adding might sleep, so schedule process
291 * context task for adding entry for STAs that do not yet
293 queue_work(local->hw.workqueue, &local->sta_debugfs_add);
296 if (ieee80211_vif_is_mesh(&sdata->vif))
297 mesh_accept_plinks_update(sdata);
302 static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
305 * This format has been mandated by the IEEE specifications,
306 * so this line may not be changed to use the __set_bit() format.
308 bss->tim[aid / 8] |= (1 << (aid % 8));
311 static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
314 * This format has been mandated by the IEEE specifications,
315 * so this line may not be changed to use the __clear_bit() format.
317 bss->tim[aid / 8] &= ~(1 << (aid % 8));
320 static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
321 struct sta_info *sta)
324 __bss_tim_set(bss, sta->aid);
325 if (sta->local->ops->set_tim) {
326 sta->local->tim_in_locked_section = true;
327 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 1);
328 sta->local->tim_in_locked_section = false;
332 void sta_info_set_tim_bit(struct sta_info *sta)
336 spin_lock_irqsave(&sta->local->sta_lock, flags);
337 __sta_info_set_tim_bit(sta->sdata->bss, sta);
338 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
341 static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
342 struct sta_info *sta)
345 __bss_tim_clear(bss, sta->aid);
346 if (sta->local->ops->set_tim) {
347 sta->local->tim_in_locked_section = true;
348 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 0);
349 sta->local->tim_in_locked_section = false;
353 void sta_info_clear_tim_bit(struct sta_info *sta)
357 spin_lock_irqsave(&sta->local->sta_lock, flags);
358 __sta_info_clear_tim_bit(sta->sdata->bss, sta);
359 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
363 * See comment in __sta_info_unlink,
364 * caller must hold local->sta_lock.
366 static void __sta_info_pin(struct sta_info *sta)
368 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
369 sta->pin_status = STA_INFO_PIN_STAT_PINNED;
373 * See comment in __sta_info_unlink, returns sta if it
374 * needs to be destroyed.
376 static struct sta_info *__sta_info_unpin(struct sta_info *sta)
378 struct sta_info *ret = NULL;
381 spin_lock_irqsave(&sta->local->sta_lock, flags);
382 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
383 sta->pin_status != STA_INFO_PIN_STAT_PINNED);
384 if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
386 sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
387 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
392 static void __sta_info_unlink(struct sta_info **sta)
394 struct ieee80211_local *local = (*sta)->local;
395 struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
396 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
397 DECLARE_MAC_BUF(mbuf);
400 * pull caller's reference if we're already gone.
402 if (sta_info_hash_del(local, *sta)) {
408 * Also pull caller's reference if the STA is pinned by the
409 * task that is adding the debugfs entries. In that case, we
410 * leave the STA "to be freed".
412 * The rules are not trivial, but not too complex either:
413 * (1) pin_status is only modified under the sta_lock
414 * (2) sta_info_debugfs_add_work() will set the status
415 * to PINNED when it found an item that needs a new
416 * debugfs directory created. In that case, that item
417 * must not be freed although all *RCU* users are done
418 * with it. Hence, we tell the caller of _unlink()
419 * that the item is already gone (as can happen when
420 * two tasks try to unlink/destroy at the same time)
421 * (3) We set the pin_status to DESTROY here when we
423 * (4) sta_info_debugfs_add_work() will reset the pin_status
424 * from PINNED to NORMAL when it is done with the item,
425 * but will check for DESTROY before resetting it in
426 * which case it will free the item.
428 if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
429 (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
434 list_del(&(*sta)->list);
436 if ((*sta)->flags & WLAN_STA_PS) {
437 (*sta)->flags &= ~WLAN_STA_PS;
439 atomic_dec(&sdata->bss->num_sta_ps);
440 __sta_info_clear_tim_bit(sdata->bss, *sta);
445 if (local->ops->sta_notify) {
446 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
447 sdata = sdata->u.vlan.ap;
449 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
450 STA_NOTIFY_REMOVE, (*sta)->addr);
453 if (ieee80211_vif_is_mesh(&sdata->vif)) {
454 mesh_accept_plinks_update(sdata);
455 #ifdef CONFIG_MAC80211_MESH
456 del_timer(&(*sta)->plink_timer);
460 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
461 printk(KERN_DEBUG "%s: Removed STA %s\n",
462 wiphy_name(local->hw.wiphy), print_mac(mbuf, (*sta)->addr));
463 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
466 void sta_info_unlink(struct sta_info **sta)
468 struct ieee80211_local *local = (*sta)->local;
471 spin_lock_irqsave(&local->sta_lock, flags);
472 __sta_info_unlink(sta);
473 spin_unlock_irqrestore(&local->sta_lock, flags);
476 static inline int sta_info_buffer_expired(struct ieee80211_local *local,
477 struct sta_info *sta,
480 struct ieee80211_tx_packet_data *pkt_data;
486 pkt_data = (struct ieee80211_tx_packet_data *) skb->cb;
488 /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
489 timeout = (sta->listen_interval * local->hw.conf.beacon_int * 32 /
491 if (timeout < STA_TX_BUFFER_EXPIRE)
492 timeout = STA_TX_BUFFER_EXPIRE;
493 return time_after(jiffies, pkt_data->jiffies + timeout);
497 static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
498 struct sta_info *sta)
502 struct ieee80211_sub_if_data *sdata;
503 DECLARE_MAC_BUF(mac);
505 if (skb_queue_empty(&sta->ps_tx_buf))
509 spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
510 skb = skb_peek(&sta->ps_tx_buf);
511 if (sta_info_buffer_expired(local, sta, skb))
512 skb = __skb_dequeue(&sta->ps_tx_buf);
515 spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
521 local->total_ps_buffered--;
522 printk(KERN_DEBUG "Buffered frame expired (STA "
523 "%s)\n", print_mac(mac, sta->addr));
526 if (skb_queue_empty(&sta->ps_tx_buf))
527 sta_info_clear_tim_bit(sta);
532 static void sta_info_cleanup(unsigned long data)
534 struct ieee80211_local *local = (struct ieee80211_local *) data;
535 struct sta_info *sta;
538 list_for_each_entry_rcu(sta, &local->sta_list, list)
539 sta_info_cleanup_expire_buffered(local, sta);
542 local->sta_cleanup.expires =
543 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
544 add_timer(&local->sta_cleanup);
547 #ifdef CONFIG_MAC80211_DEBUGFS
548 static void sta_info_debugfs_add_work(struct work_struct *work)
550 struct ieee80211_local *local =
551 container_of(work, struct ieee80211_local, sta_debugfs_add);
552 struct sta_info *sta, *tmp;
558 spin_lock_irqsave(&local->sta_lock, flags);
559 list_for_each_entry(tmp, &local->sta_list, list) {
560 if (!tmp->debugfs.dir) {
566 spin_unlock_irqrestore(&local->sta_lock, flags);
571 ieee80211_sta_debugfs_add(sta);
572 rate_control_add_sta_debugfs(sta);
574 sta = __sta_info_unpin(sta);
578 sta_info_destroy(sta);
584 void sta_info_init(struct ieee80211_local *local)
586 spin_lock_init(&local->sta_lock);
587 INIT_LIST_HEAD(&local->sta_list);
589 setup_timer(&local->sta_cleanup, sta_info_cleanup,
590 (unsigned long)local);
591 local->sta_cleanup.expires =
592 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
594 #ifdef CONFIG_MAC80211_DEBUGFS
595 INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
599 int sta_info_start(struct ieee80211_local *local)
601 add_timer(&local->sta_cleanup);
605 void sta_info_stop(struct ieee80211_local *local)
607 del_timer(&local->sta_cleanup);
608 sta_info_flush(local, NULL);
612 * sta_info_flush - flush matching STA entries from the STA table
614 * Returns the number of removed STA entries.
616 * @local: local interface data
617 * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
619 int sta_info_flush(struct ieee80211_local *local,
620 struct ieee80211_sub_if_data *sdata)
622 struct sta_info *sta, *tmp;
629 spin_lock_irqsave(&local->sta_lock, flags);
630 list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
631 if (!sdata || sdata == sta->sdata) {
632 __sta_info_unlink(&sta);
634 list_add_tail(&sta->list, &tmp_list);
639 spin_unlock_irqrestore(&local->sta_lock, flags);
643 list_for_each_entry_safe(sta, tmp, &tmp_list, list)
644 sta_info_destroy(sta);