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) {
118 if (dev && dev != sta->sdata->dev)
130 void sta_info_destroy(struct sta_info *sta)
132 struct ieee80211_local *local;
135 DECLARE_MAC_BUF(mbuf);
145 rate_control_remove_sta_debugfs(sta);
146 ieee80211_sta_debugfs_remove(sta);
148 #ifdef CONFIG_MAC80211_MESH
149 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
150 mesh_plink_deactivate(sta);
154 * NOTE: This will call synchronize_rcu() internally to
155 * make sure no key references can be in use. We rely on
156 * that here for the mesh code!
158 ieee80211_key_free(sta->key);
161 #ifdef CONFIG_MAC80211_MESH
162 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
163 del_timer_sync(&sta->plink_timer);
166 while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
167 local->total_ps_buffered--;
168 dev_kfree_skb_any(skb);
171 while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
172 dev_kfree_skb_any(skb);
174 for (i = 0; i < STA_TID_NUM; i++) {
175 spin_lock_bh(&sta->ampdu_mlme.ampdu_rx);
176 if (sta->ampdu_mlme.tid_rx[i])
177 del_timer_sync(&sta->ampdu_mlme.tid_rx[i]->session_timer);
178 spin_unlock_bh(&sta->ampdu_mlme.ampdu_rx);
179 spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
180 if (sta->ampdu_mlme.tid_tx[i])
181 del_timer_sync(&sta->ampdu_mlme.tid_tx[i]->addba_resp_timer);
182 spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
185 rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
186 rate_control_put(sta->rate_ctrl);
188 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
189 printk(KERN_DEBUG "%s: Destroyed STA %s\n",
190 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
191 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
197 /* Caller must hold local->sta_lock */
198 static void sta_info_hash_add(struct ieee80211_local *local,
199 struct sta_info *sta)
201 sta->hnext = local->sta_hash[STA_HASH(sta->addr)];
202 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], sta);
205 struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
208 struct ieee80211_local *local = sdata->local;
209 struct sta_info *sta;
211 DECLARE_MAC_BUF(mbuf);
213 sta = kzalloc(sizeof(*sta), gfp);
217 memcpy(sta->addr, addr, ETH_ALEN);
221 sta->rate_ctrl = rate_control_get(local->rate_ctrl);
222 sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
224 if (!sta->rate_ctrl_priv) {
225 rate_control_put(sta->rate_ctrl);
230 spin_lock_init(&sta->ampdu_mlme.ampdu_rx);
231 spin_lock_init(&sta->ampdu_mlme.ampdu_tx);
232 for (i = 0; i < STA_TID_NUM; i++) {
233 /* timer_to_tid must be initialized with identity mapping to
234 * enable session_timer's data differentiation. refer to
235 * sta_rx_agg_session_timer_expired for useage */
236 sta->timer_to_tid[i] = i;
237 /* tid to tx queue: initialize according to HW (0 is valid) */
238 sta->tid_to_tx_q[i] = local->hw.queues;
240 sta->ampdu_mlme.tid_state_rx[i] = HT_AGG_STATE_IDLE;
241 sta->ampdu_mlme.tid_rx[i] = NULL;
243 sta->ampdu_mlme.tid_state_tx[i] = HT_AGG_STATE_IDLE;
244 sta->ampdu_mlme.tid_tx[i] = NULL;
245 sta->ampdu_mlme.addba_req_num[i] = 0;
247 skb_queue_head_init(&sta->ps_tx_buf);
248 skb_queue_head_init(&sta->tx_filtered);
250 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
251 printk(KERN_DEBUG "%s: Allocated STA %s\n",
252 wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
253 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
255 #ifdef CONFIG_MAC80211_MESH
256 sta->plink_state = PLINK_LISTEN;
257 spin_lock_init(&sta->plink_lock);
258 init_timer(&sta->plink_timer);
264 int sta_info_insert(struct sta_info *sta)
266 struct ieee80211_local *local = sta->local;
267 struct ieee80211_sub_if_data *sdata = sta->sdata;
269 DECLARE_MAC_BUF(mac);
272 * Can't be a WARN_ON because it can be triggered through a race:
273 * something inserts a STA (on one CPU) without holding the RTNL
274 * and another CPU turns off the net device.
276 if (unlikely(!netif_running(sdata->dev)))
279 if (WARN_ON(compare_ether_addr(sta->addr, sdata->dev->dev_addr) == 0))
282 if (WARN_ON(is_multicast_ether_addr(sta->addr)))
285 spin_lock_irqsave(&local->sta_lock, flags);
286 /* check if STA exists already */
287 if (__sta_info_find(local, sta->addr)) {
288 spin_unlock_irqrestore(&local->sta_lock, flags);
291 list_add(&sta->list, &local->sta_list);
293 sta_info_hash_add(local, sta);
296 if (local->ops->sta_notify) {
297 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
298 sdata = sdata->u.vlan.ap;
300 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
301 STA_NOTIFY_ADD, sta->addr);
304 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
305 printk(KERN_DEBUG "%s: Inserted STA %s\n",
306 wiphy_name(local->hw.wiphy), print_mac(mac, sta->addr));
307 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
309 spin_unlock_irqrestore(&local->sta_lock, flags);
311 #ifdef CONFIG_MAC80211_DEBUGFS
312 /* debugfs entry adding might sleep, so schedule process
313 * context task for adding entry for STAs that do not yet
315 queue_work(local->hw.workqueue, &local->sta_debugfs_add);
318 if (ieee80211_vif_is_mesh(&sdata->vif))
319 mesh_accept_plinks_update(sdata);
324 static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
327 * This format has been mandated by the IEEE specifications,
328 * so this line may not be changed to use the __set_bit() format.
330 bss->tim[aid / 8] |= (1 << (aid % 8));
333 static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
336 * This format has been mandated by the IEEE specifications,
337 * so this line may not be changed to use the __clear_bit() format.
339 bss->tim[aid / 8] &= ~(1 << (aid % 8));
342 static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
343 struct sta_info *sta)
346 __bss_tim_set(bss, sta->aid);
347 if (sta->local->ops->set_tim) {
348 sta->local->tim_in_locked_section = true;
349 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 1);
350 sta->local->tim_in_locked_section = false;
354 void sta_info_set_tim_bit(struct sta_info *sta)
358 spin_lock_irqsave(&sta->local->sta_lock, flags);
359 __sta_info_set_tim_bit(sta->sdata->bss, sta);
360 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
363 static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
364 struct sta_info *sta)
367 __bss_tim_clear(bss, sta->aid);
368 if (sta->local->ops->set_tim) {
369 sta->local->tim_in_locked_section = true;
370 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 0);
371 sta->local->tim_in_locked_section = false;
375 void sta_info_clear_tim_bit(struct sta_info *sta)
379 spin_lock_irqsave(&sta->local->sta_lock, flags);
380 __sta_info_clear_tim_bit(sta->sdata->bss, sta);
381 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
385 * See comment in __sta_info_unlink,
386 * caller must hold local->sta_lock.
388 static void __sta_info_pin(struct sta_info *sta)
390 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
391 sta->pin_status = STA_INFO_PIN_STAT_PINNED;
395 * See comment in __sta_info_unlink, returns sta if it
396 * needs to be destroyed.
398 static struct sta_info *__sta_info_unpin(struct sta_info *sta)
400 struct sta_info *ret = NULL;
403 spin_lock_irqsave(&sta->local->sta_lock, flags);
404 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
405 sta->pin_status != STA_INFO_PIN_STAT_PINNED);
406 if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
408 sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
409 spin_unlock_irqrestore(&sta->local->sta_lock, flags);
414 static void __sta_info_unlink(struct sta_info **sta)
416 struct ieee80211_local *local = (*sta)->local;
417 struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
418 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
419 DECLARE_MAC_BUF(mbuf);
422 * pull caller's reference if we're already gone.
424 if (sta_info_hash_del(local, *sta)) {
430 * Also pull caller's reference if the STA is pinned by the
431 * task that is adding the debugfs entries. In that case, we
432 * leave the STA "to be freed".
434 * The rules are not trivial, but not too complex either:
435 * (1) pin_status is only modified under the sta_lock
436 * (2) sta_info_debugfs_add_work() will set the status
437 * to PINNED when it found an item that needs a new
438 * debugfs directory created. In that case, that item
439 * must not be freed although all *RCU* users are done
440 * with it. Hence, we tell the caller of _unlink()
441 * that the item is already gone (as can happen when
442 * two tasks try to unlink/destroy at the same time)
443 * (3) We set the pin_status to DESTROY here when we
445 * (4) sta_info_debugfs_add_work() will reset the pin_status
446 * from PINNED to NORMAL when it is done with the item,
447 * but will check for DESTROY before resetting it in
448 * which case it will free the item.
450 if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
451 (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
456 list_del(&(*sta)->list);
458 if ((*sta)->flags & WLAN_STA_PS) {
459 (*sta)->flags &= ~WLAN_STA_PS;
461 atomic_dec(&sdata->bss->num_sta_ps);
462 __sta_info_clear_tim_bit(sdata->bss, *sta);
467 if (local->ops->sta_notify) {
468 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
469 sdata = sdata->u.vlan.ap;
471 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
472 STA_NOTIFY_REMOVE, (*sta)->addr);
475 if (ieee80211_vif_is_mesh(&sdata->vif)) {
476 mesh_accept_plinks_update(sdata);
477 #ifdef CONFIG_MAC80211_MESH
478 del_timer(&(*sta)->plink_timer);
482 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
483 printk(KERN_DEBUG "%s: Removed STA %s\n",
484 wiphy_name(local->hw.wiphy), print_mac(mbuf, (*sta)->addr));
485 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
488 void sta_info_unlink(struct sta_info **sta)
490 struct ieee80211_local *local = (*sta)->local;
493 spin_lock_irqsave(&local->sta_lock, flags);
494 __sta_info_unlink(sta);
495 spin_unlock_irqrestore(&local->sta_lock, flags);
498 static inline int sta_info_buffer_expired(struct ieee80211_local *local,
499 struct sta_info *sta,
502 struct ieee80211_tx_packet_data *pkt_data;
508 pkt_data = (struct ieee80211_tx_packet_data *) skb->cb;
510 /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
511 timeout = (sta->listen_interval * local->hw.conf.beacon_int * 32 /
513 if (timeout < STA_TX_BUFFER_EXPIRE)
514 timeout = STA_TX_BUFFER_EXPIRE;
515 return time_after(jiffies, pkt_data->jiffies + timeout);
519 static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
520 struct sta_info *sta)
524 struct ieee80211_sub_if_data *sdata;
525 DECLARE_MAC_BUF(mac);
527 if (skb_queue_empty(&sta->ps_tx_buf))
531 spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
532 skb = skb_peek(&sta->ps_tx_buf);
533 if (sta_info_buffer_expired(local, sta, skb))
534 skb = __skb_dequeue(&sta->ps_tx_buf);
537 spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
543 local->total_ps_buffered--;
544 printk(KERN_DEBUG "Buffered frame expired (STA "
545 "%s)\n", print_mac(mac, sta->addr));
548 if (skb_queue_empty(&sta->ps_tx_buf))
549 sta_info_clear_tim_bit(sta);
554 static void sta_info_cleanup(unsigned long data)
556 struct ieee80211_local *local = (struct ieee80211_local *) data;
557 struct sta_info *sta;
560 list_for_each_entry_rcu(sta, &local->sta_list, list)
561 sta_info_cleanup_expire_buffered(local, sta);
564 local->sta_cleanup.expires =
565 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
566 add_timer(&local->sta_cleanup);
569 #ifdef CONFIG_MAC80211_DEBUGFS
570 static void sta_info_debugfs_add_work(struct work_struct *work)
572 struct ieee80211_local *local =
573 container_of(work, struct ieee80211_local, sta_debugfs_add);
574 struct sta_info *sta, *tmp;
580 spin_lock_irqsave(&local->sta_lock, flags);
581 list_for_each_entry(tmp, &local->sta_list, list) {
582 if (!tmp->debugfs.dir) {
588 spin_unlock_irqrestore(&local->sta_lock, flags);
593 ieee80211_sta_debugfs_add(sta);
594 rate_control_add_sta_debugfs(sta);
596 sta = __sta_info_unpin(sta);
600 sta_info_destroy(sta);
606 void sta_info_init(struct ieee80211_local *local)
608 spin_lock_init(&local->sta_lock);
609 INIT_LIST_HEAD(&local->sta_list);
611 setup_timer(&local->sta_cleanup, sta_info_cleanup,
612 (unsigned long)local);
613 local->sta_cleanup.expires =
614 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
616 #ifdef CONFIG_MAC80211_DEBUGFS
617 INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
621 int sta_info_start(struct ieee80211_local *local)
623 add_timer(&local->sta_cleanup);
627 void sta_info_stop(struct ieee80211_local *local)
629 del_timer(&local->sta_cleanup);
630 sta_info_flush(local, NULL);
634 * sta_info_flush - flush matching STA entries from the STA table
636 * Returns the number of removed STA entries.
638 * @local: local interface data
639 * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
641 int sta_info_flush(struct ieee80211_local *local,
642 struct ieee80211_sub_if_data *sdata)
644 struct sta_info *sta, *tmp;
651 spin_lock_irqsave(&local->sta_lock, flags);
652 list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
653 if (!sdata || sdata == sta->sdata) {
654 __sta_info_unlink(&sta);
656 list_add_tail(&sta->list, &tmp_list);
661 spin_unlock_irqrestore(&local->sta_lock, flags);
665 list_for_each_entry_safe(sta, tmp, &tmp_list, list)
666 sta_info_destroy(sta);