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.
41 * Because there are debugfs entries for each station, and adding those
42 * must be able to sleep, it is also possible to "pin" a station entry,
43 * that means it can be removed from the hash table but not be freed.
44 * See the comment in __sta_info_unlink() for more information.
46 * In order to remove a STA info structure, the caller needs to first
47 * unlink it (sta_info_unlink()) from the list and hash tables and
48 * then wait for an RCU synchronisation before it can be freed. Due to
49 * the pinning and the possibility of multiple callers trying to remove
50 * the same STA info at the same time, sta_info_unlink() can clear the
51 * STA info pointer it is passed to indicate that the STA info is owned
52 * by somebody else now.
54 * If sta_info_unlink() did not clear the pointer then the caller owns
55 * the STA info structure now and is responsible of destroying it with
56 * a call to sta_info_destroy(), not before RCU synchronisation, of
57 * course. Note that sta_info_destroy() must be protected by the RTNL.
59 * In all other cases, there is no concept of ownership on a STA entry,
60 * each structure is owned by the global hash table/list until it is
61 * removed. All users of the structure need to be RCU protected so that
62 * the structure won't be freed before they are done using it.
65 /* Caller must hold local->sta_lock */
66 static int sta_info_hash_del(struct ieee80211_local *local,
71 s = local->sta_hash[STA_HASH(sta->addr)];
75 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)],
80 while (s->hnext && s->hnext != sta)
83 rcu_assign_pointer(s->hnext, sta->hnext);
90 /* protected by RCU */
91 static struct sta_info *__sta_info_find(struct ieee80211_local *local,
96 sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
98 if (compare_ether_addr(sta->addr, addr) == 0)
100 sta = rcu_dereference(sta->hnext);
105 struct sta_info *sta_info_get(struct ieee80211_local *local, u8 *addr)
107 return __sta_info_find(local, addr);
109 EXPORT_SYMBOL(sta_info_get);
111 struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx,
112 struct net_device *dev)
114 struct sta_info *sta;
117 list_for_each_entry_rcu(sta, &local->sta_list, list) {
121 } else if (!dev || dev == sta->sdata->dev) {
129 void sta_info_destroy(struct sta_info *sta)
131 struct ieee80211_local *local = sta->local;
134 DECLARE_MAC_BUF(mbuf);
142 rate_control_remove_sta_debugfs(sta);
143 ieee80211_sta_debugfs_remove(sta);
145 #ifdef CONFIG_MAC80211_MESH
146 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
147 mesh_plink_deactivate(sta);
151 * NOTE: This will call synchronize_rcu() internally to
152 * make sure no key references can be in use. We rely on
153 * that here for the mesh code!
155 ieee80211_key_free(sta->key);
158 #ifdef CONFIG_MAC80211_MESH
159 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
160 del_timer_sync(&sta->plink_timer);
163 while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
164 local->total_ps_buffered--;
165 dev_kfree_skb_any(skb);
168 while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
169 dev_kfree_skb_any(skb);
171 for (i = 0; i < STA_TID_NUM; i++) {
172 del_timer_sync(&sta->ampdu_mlme.tid_rx[i].session_timer);
173 del_timer_sync(&sta->ampdu_mlme.tid_tx[i].addba_resp_timer);
175 rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
176 rate_control_put(sta->rate_ctrl);
178 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
179 printk(KERN_DEBUG "%s: Destroyed STA %s\n",
180 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
181 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
187 /* Caller must hold local->sta_lock */
188 static void sta_info_hash_add(struct ieee80211_local *local,
189 struct sta_info *sta)
191 sta->hnext = local->sta_hash[STA_HASH(sta->addr)];
192 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], sta);
195 struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
198 struct ieee80211_local *local = sdata->local;
199 struct sta_info *sta;
201 DECLARE_MAC_BUF(mbuf);
203 sta = kzalloc(sizeof(*sta), gfp);
207 memcpy(sta->addr, addr, ETH_ALEN);
211 sta->rate_ctrl = rate_control_get(local->rate_ctrl);
212 sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
214 if (!sta->rate_ctrl_priv) {
215 rate_control_put(sta->rate_ctrl);
220 spin_lock_init(&sta->ampdu_mlme.ampdu_rx);
221 spin_lock_init(&sta->ampdu_mlme.ampdu_tx);
222 for (i = 0; i < STA_TID_NUM; i++) {
223 /* timer_to_tid must be initialized with identity mapping to
224 * enable session_timer's data differentiation. refer to
225 * sta_rx_agg_session_timer_expired for useage */
226 sta->timer_to_tid[i] = i;
227 /* tid to tx queue: initialize according to HW (0 is valid) */
228 sta->tid_to_tx_q[i] = local->hw.queues;
230 sta->ampdu_mlme.tid_rx[i].session_timer.function =
231 sta_rx_agg_session_timer_expired;
232 sta->ampdu_mlme.tid_rx[i].session_timer.data =
233 (unsigned long)&sta->timer_to_tid[i];
234 init_timer(&sta->ampdu_mlme.tid_rx[i].session_timer);
236 sta->ampdu_mlme.tid_tx[i].addba_resp_timer.function =
237 sta_addba_resp_timer_expired;
238 sta->ampdu_mlme.tid_tx[i].addba_resp_timer.data =
239 (unsigned long)&sta->timer_to_tid[i];
240 init_timer(&sta->ampdu_mlme.tid_tx[i].addba_resp_timer);
242 skb_queue_head_init(&sta->ps_tx_buf);
243 skb_queue_head_init(&sta->tx_filtered);
245 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
246 printk(KERN_DEBUG "%s: Allocated STA %s\n",
247 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
248 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
250 #ifdef CONFIG_MAC80211_MESH
251 sta->plink_state = PLINK_LISTEN;
252 spin_lock_init(&sta->plink_lock);
253 init_timer(&sta->plink_timer);
259 int sta_info_insert(struct sta_info *sta)
261 struct ieee80211_local *local = sta->local;
262 struct ieee80211_sub_if_data *sdata = sta->sdata;
264 DECLARE_MAC_BUF(mac);
267 * Can't be a WARN_ON because it can be triggered through a race:
268 * something inserts a STA (on one CPU) without holding the RTNL
269 * and another CPU turns off the net device.
271 if (unlikely(!netif_running(sdata->dev)))
274 if (WARN_ON(compare_ether_addr(sta->addr, sdata->dev->dev_addr) == 0))
277 if (WARN_ON(is_multicast_ether_addr(sta->addr)))
280 spin_lock_irqsave(&local->sta_lock, flags);
281 /* check if STA exists already */
282 if (__sta_info_find(local, sta->addr)) {
283 spin_unlock_irqrestore(&local->sta_lock, flags);
286 list_add(&sta->list, &local->sta_list);
288 sta_info_hash_add(local, sta);
291 if (local->ops->sta_notify) {
292 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
293 sdata = sdata->u.vlan.ap;
295 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
296 STA_NOTIFY_ADD, sta->addr);
299 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
300 printk(KERN_DEBUG "%s: Inserted STA %s\n",
301 wiphy_name(local->hw.wiphy), print_mac(mac, sta->addr));
302 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
304 spin_unlock_irqrestore(&local->sta_lock, flags);
306 #ifdef CONFIG_MAC80211_DEBUGFS
307 /* debugfs entry adding might sleep, so schedule process
308 * context task for adding entry for STAs that do not yet
310 queue_work(local->hw.workqueue, &local->sta_debugfs_add);
313 if (ieee80211_vif_is_mesh(&sdata->vif))
314 mesh_accept_plinks_update(sdata);
319 static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
322 * This format has been mandated by the IEEE specifications,
323 * so this line may not be changed to use the __set_bit() format.
325 bss->tim[aid / 8] |= (1 << (aid % 8));
328 static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
331 * This format has been mandated by the IEEE specifications,
332 * so this line may not be changed to use the __clear_bit() format.
334 bss->tim[aid / 8] &= ~(1 << (aid % 8));
337 static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
338 struct sta_info *sta)
341 __bss_tim_set(bss, sta->aid);
342 if (sta->local->ops->set_tim) {
343 sta->local->tim_in_locked_section = true;
344 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 1);
345 sta->local->tim_in_locked_section = false;
349 void sta_info_set_tim_bit(struct sta_info *sta)
353 spin_lock_irqsave(&sta->local->sta_lock, flags);
354 __sta_info_set_tim_bit(sta->sdata->bss, sta);
355 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
358 static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
359 struct sta_info *sta)
362 __bss_tim_clear(bss, sta->aid);
363 if (sta->local->ops->set_tim) {
364 sta->local->tim_in_locked_section = true;
365 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 0);
366 sta->local->tim_in_locked_section = false;
370 void sta_info_clear_tim_bit(struct sta_info *sta)
374 spin_lock_irqsave(&sta->local->sta_lock, flags);
375 __sta_info_clear_tim_bit(sta->sdata->bss, sta);
376 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
380 * See comment in __sta_info_unlink,
381 * caller must hold local->sta_lock.
383 static void __sta_info_pin(struct sta_info *sta)
385 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
386 sta->pin_status = STA_INFO_PIN_STAT_PINNED;
390 * See comment in __sta_info_unlink, returns sta if it
391 * needs to be destroyed.
393 static struct sta_info *__sta_info_unpin(struct sta_info *sta)
395 struct sta_info *ret = NULL;
398 spin_lock_irqsave(&sta->local->sta_lock, flags);
399 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
400 sta->pin_status != STA_INFO_PIN_STAT_PINNED);
401 if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
403 sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
404 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
409 static void __sta_info_unlink(struct sta_info **sta)
411 struct ieee80211_local *local = (*sta)->local;
412 struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
413 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
414 DECLARE_MAC_BUF(mbuf);
417 * pull caller's reference if we're already gone.
419 if (sta_info_hash_del(local, *sta)) {
425 * Also pull caller's reference if the STA is pinned by the
426 * task that is adding the debugfs entries. In that case, we
427 * leave the STA "to be freed".
429 * The rules are not trivial, but not too complex either:
430 * (1) pin_status is only modified under the sta_lock
431 * (2) sta_info_debugfs_add_work() will set the status
432 * to PINNED when it found an item that needs a new
433 * debugfs directory created. In that case, that item
434 * must not be freed although all *RCU* users are done
435 * with it. Hence, we tell the caller of _unlink()
436 * that the item is already gone (as can happen when
437 * two tasks try to unlink/destroy at the same time)
438 * (3) We set the pin_status to DESTROY here when we
440 * (4) sta_info_debugfs_add_work() will reset the pin_status
441 * from PINNED to NORMAL when it is done with the item,
442 * but will check for DESTROY before resetting it in
443 * which case it will free the item.
445 if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
446 (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
451 list_del(&(*sta)->list);
453 if ((*sta)->flags & WLAN_STA_PS) {
454 (*sta)->flags &= ~WLAN_STA_PS;
456 atomic_dec(&sdata->bss->num_sta_ps);
457 __sta_info_clear_tim_bit(sdata->bss, *sta);
462 if (local->ops->sta_notify) {
463 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
464 sdata = sdata->u.vlan.ap;
466 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
467 STA_NOTIFY_REMOVE, (*sta)->addr);
470 if (ieee80211_vif_is_mesh(&sdata->vif)) {
471 mesh_accept_plinks_update(sdata);
472 #ifdef CONFIG_MAC80211_MESH
473 del_timer(&(*sta)->plink_timer);
477 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
478 printk(KERN_DEBUG "%s: Removed STA %s\n",
479 wiphy_name(local->hw.wiphy), print_mac(mbuf, (*sta)->addr));
480 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
483 void sta_info_unlink(struct sta_info **sta)
485 struct ieee80211_local *local = (*sta)->local;
488 spin_lock_irqsave(&local->sta_lock, flags);
489 __sta_info_unlink(sta);
490 spin_unlock_irqrestore(&local->sta_lock, flags);
493 static inline int sta_info_buffer_expired(struct ieee80211_local *local,
494 struct sta_info *sta,
497 struct ieee80211_tx_packet_data *pkt_data;
503 pkt_data = (struct ieee80211_tx_packet_data *) skb->cb;
505 /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
506 timeout = (sta->listen_interval * local->hw.conf.beacon_int * 32 /
508 if (timeout < STA_TX_BUFFER_EXPIRE)
509 timeout = STA_TX_BUFFER_EXPIRE;
510 return time_after(jiffies, pkt_data->jiffies + timeout);
514 static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
515 struct sta_info *sta)
519 struct ieee80211_sub_if_data *sdata;
520 DECLARE_MAC_BUF(mac);
522 if (skb_queue_empty(&sta->ps_tx_buf))
526 spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
527 skb = skb_peek(&sta->ps_tx_buf);
528 if (sta_info_buffer_expired(local, sta, skb))
529 skb = __skb_dequeue(&sta->ps_tx_buf);
532 spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
538 local->total_ps_buffered--;
539 printk(KERN_DEBUG "Buffered frame expired (STA "
540 "%s)\n", print_mac(mac, sta->addr));
543 if (skb_queue_empty(&sta->ps_tx_buf))
544 sta_info_clear_tim_bit(sta);
549 static void sta_info_cleanup(unsigned long data)
551 struct ieee80211_local *local = (struct ieee80211_local *) data;
552 struct sta_info *sta;
555 list_for_each_entry_rcu(sta, &local->sta_list, list)
556 sta_info_cleanup_expire_buffered(local, sta);
559 local->sta_cleanup.expires =
560 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
561 add_timer(&local->sta_cleanup);
564 #ifdef CONFIG_MAC80211_DEBUGFS
565 static void sta_info_debugfs_add_work(struct work_struct *work)
567 struct ieee80211_local *local =
568 container_of(work, struct ieee80211_local, sta_debugfs_add);
569 struct sta_info *sta, *tmp;
575 spin_lock_irqsave(&local->sta_lock, flags);
576 list_for_each_entry(tmp, &local->sta_list, list) {
577 if (!tmp->debugfs.dir) {
583 spin_unlock_irqrestore(&local->sta_lock, flags);
588 ieee80211_sta_debugfs_add(sta);
589 rate_control_add_sta_debugfs(sta);
591 sta = __sta_info_unpin(sta);
595 sta_info_destroy(sta);
601 void sta_info_init(struct ieee80211_local *local)
603 spin_lock_init(&local->sta_lock);
604 INIT_LIST_HEAD(&local->sta_list);
606 setup_timer(&local->sta_cleanup, sta_info_cleanup,
607 (unsigned long)local);
608 local->sta_cleanup.expires =
609 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
611 #ifdef CONFIG_MAC80211_DEBUGFS
612 INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
616 int sta_info_start(struct ieee80211_local *local)
618 add_timer(&local->sta_cleanup);
622 void sta_info_stop(struct ieee80211_local *local)
624 del_timer(&local->sta_cleanup);
625 sta_info_flush(local, NULL);
629 * sta_info_flush - flush matching STA entries from the STA table
631 * Returns the number of removed STA entries.
633 * @local: local interface data
634 * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
636 int sta_info_flush(struct ieee80211_local *local,
637 struct ieee80211_sub_if_data *sdata)
639 struct sta_info *sta, *tmp;
646 spin_lock_irqsave(&local->sta_lock, flags);
647 list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
648 if (!sdata || sdata == sta->sdata) {
649 __sta_info_unlink(&sta);
651 list_add_tail(&sta->list, &tmp_list);
656 spin_unlock_irqrestore(&local->sta_lock, flags);
660 list_for_each_entry_safe(sta, tmp, &tmp_list, list)
661 sta_info_destroy(sta);