/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/timer.h>
#include <linux/rtnetlink.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
#include "rate.h"
#include "sta_info.h"
#include "debugfs_sta.h"
#include "mesh.h"
/**
* DOC: STA information lifetime rules
*
* STA info structures (&struct sta_info) are managed in a hash table
* for faster lookup and a list for iteration. They are managed using
* RCU, i.e. access to the list and hash table is protected by RCU.
*
* Upon allocating a STA info structure with sta_info_alloc(), the caller owns
* that structure. It must then either destroy it using sta_info_destroy()
* (which is pretty useless) or insert it into the hash table using
* sta_info_insert() which demotes the reference from ownership to a regular
* RCU-protected reference; if the function is called without protection by an
* RCU critical section the reference is instantly invalidated. Note that the
* caller may not do much with the STA info before inserting it, in particular,
* it may not start any mesh peer link management or add encryption keys.
*
* When the insertion fails (sta_info_insert()) returns non-zero), the
* structure will have been freed by sta_info_insert()!
*
* Because there are debugfs entries for each station, and adding those
* must be able to sleep, it is also possible to "pin" a station entry,
* that means it can be removed from the hash table but not be freed.
* See the comment in __sta_info_unlink() for more information, this is
* an internal capability only.
*
* In order to remove a STA info structure, the caller needs to first
* unlink it (sta_info_unlink()) from the list and hash tables and
* then destroy it; sta_info_destroy() will wait for an RCU grace period
* to elapse before actually freeing it. Due to the pinning and the
* possibility of multiple callers trying to remove the same STA info at
* the same time, sta_info_unlink() can clear the STA info pointer it is
* passed to indicate that the STA info is owned by somebody else now.
*
* If sta_info_unlink() did not clear the pointer then the caller owns
* the STA info structure now and is responsible of destroying it with
* a call to sta_info_destroy().
*
* In all other cases, there is no concept of ownership on a STA entry,
* each structure is owned by the global hash table/list until it is
* removed. All users of the structure need to be RCU protected so that
* the structure won't be freed before they are done using it.
*/
/* Caller must hold local->sta_lock */
static int sta_info_hash_del(struct ieee80211_local *local,
struct sta_info *sta)
{
struct sta_info *s;
s = local->sta_hash[STA_HASH(sta->sta.addr)];
if (!s)
return -ENOENT;
if (s == sta) {
rcu_assign_pointer(local->sta_hash[STA_HASH(sta->sta.addr)],
s->hnext);
return 0;
}
while (s->hnext && s->hnext != sta)
s = s->hnext;
if (s->hnext) {
rcu_assign_pointer(s->hnext, sta->hnext);
return 0;
}
return -ENOENT;
}
/* protected by RCU */
struct sta_info *sta_info_get(struct ieee80211_local *local, const u8 *addr)
{
struct sta_info *sta;
sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
while (sta) {
if (memcmp(sta->sta.addr, addr, ETH_ALEN) == 0)
break;
sta = rcu_dereference(sta->hnext);
}
return sta;
}
struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx,
struct net_device *dev)
{
struct sta_info *sta;
int i = 0;
list_for_each_entry_rcu(sta, &local->sta_list, list) {
if (dev && dev != sta->sdata->dev)
continue;
if (i < idx) {
++i;
continue;
}
return sta;
}
return NULL;
}
/**
* __sta_info_free - internal STA free helper
*
* @local: pointer to the global information
* @sta: STA info to free
*
* This function must undo everything done by sta_info_alloc()
* that may happen before sta_info_insert().
*/
static void __sta_info_free(struct ieee80211_local *local,
struct sta_info *sta)
{
rate_control_free_sta(sta);
rate_control_put(sta->rate_ctrl);
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Destroyed STA %pM\n",
wiphy_name(local->hw.wiphy), sta->sta.addr);
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
kfree(sta);
}
void sta_info_destroy(struct sta_info *sta)
{
struct ieee80211_local *local;
struct sk_buff *skb;
int i;
might_sleep();
if (!sta)
return;
local = sta->local;
rate_control_remove_sta_debugfs(sta);
ieee80211_sta_debugfs_remove(sta);
#ifdef CONFIG_MAC80211_MESH
if (ieee80211_vif_is_mesh(&sta->sdata->vif))
mesh_plink_deactivate(sta);
#endif
/*
* We have only unlinked the key, and actually destroying it
* may mean it is removed from hardware which requires that
* the key->sta pointer is still valid, so flush the key todo
* list here.
*
* ieee80211_key_todo() will synchronize_rcu() so after this
* nothing can reference this sta struct any more.
*/
ieee80211_key_todo();
#ifdef CONFIG_MAC80211_MESH
if (ieee80211_vif_is_mesh(&sta->sdata->vif))
del_timer_sync(&sta->plink_timer);
#endif
while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
local->total_ps_buffered--;
dev_kfree_skb_any(skb);
}
while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
dev_kfree_skb_any(skb);
for (i = 0; i < STA_TID_NUM; i++) {
struct tid_ampdu_rx *tid_rx;
struct tid_ampdu_tx *tid_tx;
spin_lock_bh(&sta->lock);
tid_rx = sta->ampdu_mlme.tid_rx[i];
/* Make sure timer won't free the tid_rx struct, see below */
if (tid_rx)
tid_rx->shutdown = true;
spin_unlock_bh(&sta->lock);
/*
* Outside spinlock - shutdown is true now so that the timer
* won't free tid_rx, we have to do that now. Can't let the
* timer do it because we have to sync the timer outside the
* lock that it takes itself.
*/
if (tid_rx) {
del_timer_sync(&tid_rx->session_timer);
kfree(tid_rx);
}
/*
* No need to do such complications for TX agg sessions, the
* path leading to freeing the tid_tx struct goes via a call
* from the driver, and thus needs to look up the sta struct
* again, which cannot be found when we get here. Hence, we
* just need to delete the timer and free the aggregation
* info; we won't be telling the peer about it then but that
* doesn't matter if we're not talking to it again anyway.
*/
tid_tx = sta->ampdu_mlme.tid_tx[i];
if (tid_tx) {
del_timer_sync(&tid_tx->addba_resp_timer);
/*
* STA removed while aggregation session being
* started? Bit odd, but purge frames anyway.
*/
skb_queue_purge(&tid_tx->pending);
kfree(tid_tx);
}
}
__sta_info_free(local, sta);
}
/* Caller must hold local->sta_lock */
static void sta_info_hash_add(struct ieee80211_local *local,
struct sta_info *sta)
{
sta->hnext = local->sta_hash[STA_HASH(sta->sta.addr)];
rcu_assign_pointer(local->sta_hash[STA_HASH(sta->sta.addr)], sta);
}
struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
u8 *addr, gfp_t gfp)
{
struct ieee80211_local *local = sdata->local;
struct sta_info *sta;
int i;
sta = kzalloc(sizeof(*sta) + local->hw.sta_data_size, gfp);
if (!sta)
return NULL;
spin_lock_init(&sta->lock);
spin_lock_init(&sta->flaglock);
memcpy(sta->sta.addr, addr, ETH_ALEN);
sta->local = local;
sta->sdata = sdata;
sta->rate_ctrl = rate_control_get(local->rate_ctrl);
sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
&sta->sta, gfp);
if (!sta->rate_ctrl_priv) {
rate_control_put(sta->rate_ctrl);
kfree(sta);
return NULL;
}
for (i = 0; i < STA_TID_NUM; i++) {
/* timer_to_tid must be initialized with identity mapping to
* enable session_timer's data differentiation. refer to
* sta_rx_agg_session_timer_expired for useage */
sta->timer_to_tid[i] = i;
/* rx */
sta->ampdu_mlme.tid_state_rx[i] = HT_AGG_STATE_IDLE;
sta->ampdu_mlme.tid_rx[i] = NULL;
/* tx */
sta->ampdu_mlme.tid_state_tx[i] = HT_AGG_STATE_IDLE;
sta->ampdu_mlme.tid_tx[i] = NULL;
sta->ampdu_mlme.addba_req_num[i] = 0;
}
skb_queue_head_init(&sta->ps_tx_buf);
skb_queue_head_init(&sta->tx_filtered);
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Allocated STA %pM\n",
wiphy_name(local->hw.wiphy), sta->sta.addr);
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
#ifdef CONFIG_MAC80211_MESH
sta->plink_state = PLINK_LISTEN;
init_timer(&sta->plink_timer);
#endif
return sta;
}
int sta_info_insert(struct sta_info *sta)
{
struct ieee80211_local *local = sta->local;
struct ieee80211_sub_if_data *sdata = sta->sdata;
unsigned long flags;
int err = 0;
/*
* Can't be a WARN_ON because it can be triggered through a race:
* something inserts a STA (on one CPU) without holding the RTNL
* and another CPU turns off the net device.
*/
if (unlikely(!netif_running(sdata->dev))) {
err = -ENETDOWN;
goto out_free;
}
if (WARN_ON(compare_ether_addr(sta->sta.addr, sdata->dev->dev_addr) == 0 ||
is_multicast_ether_addr(sta->sta.addr))) {
err = -EINVAL;
goto out_free;
}
spin_lock_irqsave(&local->sta_lock, flags);
/* check if STA exists already */
if (sta_info_get(local, sta->sta.addr)) {
spin_unlock_irqrestore(&local->sta_lock, flags);
err = -EEXIST;
goto out_free;
}
list_add(&sta->list, &local->sta_list);
local->num_sta++;
sta_info_hash_add(local, sta);
/* notify driver */
if (local->ops->sta_notify) {
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
sdata = container_of(sdata->bss,
struct ieee80211_sub_if_data,
u.ap);
drv_sta_notify(local, &sdata->vif, STA_NOTIFY_ADD, &sta->sta);
}
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Inserted STA %pM\n",
wiphy_name(local->hw.wiphy), sta->sta.addr);
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
spin_unlock_irqrestore(&local->sta_lock, flags);
#ifdef CONFIG_MAC80211_DEBUGFS
/*
* Debugfs entry adding might sleep, so schedule process
* context task for adding entry for STAs that do not yet
* have one.
* NOTE: due to auto-freeing semantics this may only be done
* if the insertion is successful!
*/
schedule_work(&local->sta_debugfs_add);
#endif
if (ieee80211_vif_is_mesh(&sdata->vif))
mesh_accept_plinks_update(sdata);
return 0;
out_free:
BUG_ON(!err);
__sta_info_free(local, sta);
return err;
}
static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
{
/*
* This format has been mandated by the IEEE specifications,
* so this line may not be changed to use the __set_bit() format.
*/
bss->tim[aid / 8] |= (1 << (aid % 8));
}
static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
{
/*
* This format has been mandated by the IEEE specifications,
* so this line may not be changed to use the __clear_bit() format.
*/
bss->tim[aid / 8] &= ~(1 << (aid % 8));
}
static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
struct sta_info *sta)
{
BUG_ON(!bss);
__bss_tim_set(bss, sta->sta.aid);
if (sta->local->ops->set_tim) {
sta->local->tim_in_locked_section = true;
drv_set_tim(sta->local, &sta->sta, true);
sta->local->tim_in_locked_section = false;
}
}
void sta_info_set_tim_bit(struct sta_info *sta)
{
unsigned long flags;
BUG_ON(!sta->sdata->bss);
spin_lock_irqsave(&sta->local->sta_lock, flags);
__sta_info_set_tim_bit(sta->sdata->bss, sta);
spin_unlock_irqrestore(&sta->local->sta_lock, flags);
}
static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
struct sta_info *sta)
{
BUG_ON(!bss);
__bss_tim_clear(bss, sta->sta.aid);
if (sta->local->ops->set_tim) {
sta->local->tim_in_locked_section = true;
drv_set_tim(sta->local, &sta->sta, false);
sta->local->tim_in_locked_section = false;
}
}
void sta_info_clear_tim_bit(struct sta_info *sta)
{
unsigned long flags;
BUG_ON(!sta->sdata->bss);
spin_lock_irqsave(&sta->local->sta_lock, flags);
__sta_info_clear_tim_bit(sta->sdata->bss, sta);
spin_unlock_irqrestore(&sta->local->sta_lock, flags);
}
static void __sta_info_unlink(struct sta_info **sta)
{
struct ieee80211_local *local = (*sta)->local;
struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
/*
* pull caller's reference if we're already gone.
*/
if (sta_info_hash_del(local, *sta)) {
*sta = NULL;
return;
}
if ((*sta)->key) {
ieee80211_key_free((*sta)->key);
WARN_ON((*sta)->key);
}
list_del(&(*sta)->list);
if (test_and_clear_sta_flags(*sta, WLAN_STA_PS)) {
BUG_ON(!sdata->bss);
atomic_dec(&sdata->bss->num_sta_ps);
__sta_info_clear_tim_bit(sdata->bss, *sta);
}
local->num_sta--;
if (local->ops->sta_notify) {
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
sdata = container_of(sdata->bss,
struct ieee80211_sub_if_data,
u.ap);
drv_sta_notify(local, &sdata->vif, STA_NOTIFY_REMOVE,
&(*sta)->sta);
}
if (ieee80211_vif_is_mesh(&sdata->vif)) {
mesh_accept_plinks_update(sdata);
#ifdef CONFIG_MAC80211_MESH
del_timer(&(*sta)->plink_timer);
#endif
}
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Removed STA %pM\n",
wiphy_name(local->hw.wiphy), (*sta)->sta.addr);
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
/*
* Finally, pull caller's reference if the STA is pinned by the
* task that is adding the debugfs entries. In that case, we
* leave the STA "to be freed".
*
* The rules are not trivial, but not too complex either:
* (1) pin_status is only modified under the sta_lock
* (2) STAs may only be pinned under the RTNL so that
* sta_info_flush() is guaranteed to actually destroy
* all STAs that are active for a given interface, this
* is required for correctness because otherwise we
* could notify a driver that an interface is going
* away and only after that (!) notify it about a STA
* on that interface going away.
* (3) sta_info_debugfs_add_work() will set the status
* to PINNED when it found an item that needs a new
* debugfs directory created. In that case, that item
* must not be freed although all *RCU* users are done
* with it. Hence, we tell the caller of _unlink()
* that the item is already gone (as can happen when
* two tasks try to unlink/destroy at the same time)
* (4) We set the pin_status to DESTROY here when we
* find such an item.
* (5) sta_info_debugfs_add_work() will reset the pin_status
* from PINNED to NORMAL when it is done with the item,
* but will check for DESTROY before resetting it in
* which case it will free the item.
*/
if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
(*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
*sta = NULL;
return;
}
}
void sta_info_unlink(struct sta_info **sta)
{
struct ieee80211_local *local = (*sta)->local;
unsigned long flags;
spin_lock_irqsave(&local->sta_lock, flags);
__sta_info_unlink(sta);
spin_unlock_irqrestore(&local->sta_lock, flags);
}
static int sta_info_buffer_expired(struct sta_info *sta,
struct sk_buff *skb)
{
struct ieee80211_tx_info *info;
int timeout;
if (!skb)
return 0;
info = IEEE80211_SKB_CB(skb);
/* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
timeout = (sta->listen_interval *
sta->sdata->vif.bss_conf.beacon_int *
32 / 15625) * HZ;
if (timeout < STA_TX_BUFFER_EXPIRE)
timeout = STA_TX_BUFFER_EXPIRE;
return time_after(jiffies, info->control.jiffies + timeout);
}
static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
struct sta_info *sta)
{
unsigned long flags;
struct sk_buff *skb;
struct ieee80211_sub_if_data *sdata;
if (skb_queue_empty(&sta->ps_tx_buf))
return;
for (;;) {
spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
skb = skb_peek(&sta->ps_tx_buf);
if (sta_info_buffer_expired(sta, skb))
skb = __skb_dequeue(&sta->ps_tx_buf);
else
skb = NULL;
spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
if (!skb)
break;
sdata = sta->sdata;
local->total_ps_buffered--;
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
printk(KERN_DEBUG "Buffered frame expired (STA %pM)\n",
sta->sta.addr);
#endif
dev_kfree_skb(skb);
if (skb_queue_empty(&sta->ps_tx_buf))
sta_info_clear_tim_bit(sta);
}
}
static void sta_info_cleanup(unsigned long data)
{
struct ieee80211_local *local = (struct ieee80211_local *) data;
struct sta_info *sta;
rcu_read_lock();
list_for_each_entry_rcu(sta, &local->sta_list, list)
sta_info_cleanup_expire_buffered(local, sta);
rcu_read_unlock();
local->sta_cleanup.expires =
round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
add_timer(&local->sta_cleanup);
}
#ifdef CONFIG_MAC80211_DEBUGFS
/*
* See comment in __sta_info_unlink,
* caller must hold local->sta_lock.
*/
static void __sta_info_pin(struct sta_info *sta)
{
WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
sta->pin_status = STA_INFO_PIN_STAT_PINNED;
}
/*
* See comment in __sta_info_unlink, returns sta if it
* needs to be destroyed.
*/
static struct sta_info *__sta_info_unpin(struct sta_info *sta)
{
struct sta_info *ret = NULL;
unsigned long flags;
spin_lock_irqsave(&sta->local->sta_lock, flags);
WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
sta->pin_status != STA_INFO_PIN_STAT_PINNED);
if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
ret = sta;
sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
spin_unlock_irqrestore(&sta->local->sta_lock, flags);
return ret;
}
static void sta_info_debugfs_add_work(struct work_struct *work)
{
struct ieee80211_local *local =
container_of(work, struct ieee80211_local, sta_debugfs_add);
struct sta_info *sta, *tmp;
unsigned long flags;
/* We need to keep the RTNL across the whole pinned status. */
rtnl_lock();
while (1) {
sta = NULL;
spin_lock_irqsave(&local->sta_lock, flags);
list_for_each_entry(tmp, &local->sta_list, list) {
/*
* debugfs.add_has_run will be set by
* ieee80211_sta_debugfs_add regardless
* of what else it does.
*/
if (!tmp->debugfs.add_has_run) {
sta = tmp;
__sta_info_pin(sta);
break;
}
}
spin_unlock_irqrestore(&local->sta_lock, flags);
if (!sta)
break;
ieee80211_sta_debugfs_add(sta);
rate_control_add_sta_debugfs(sta);
sta = __sta_info_unpin(sta);
sta_info_destroy(sta);
}
rtnl_unlock();
}
#endif
void sta_info_init(struct ieee80211_local *local)
{
spin_lock_init(&local->sta_lock);
INIT_LIST_HEAD(&local->sta_list);
setup_timer(&local->sta_cleanup, sta_info_cleanup,
(unsigned long)local);
local->sta_cleanup.expires =
round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
#ifdef CONFIG_MAC80211_DEBUGFS
INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
#endif
}
int sta_info_start(struct ieee80211_local *local)
{
add_timer(&local->sta_cleanup);
return 0;
}
void sta_info_stop(struct ieee80211_local *local)
{
del_timer(&local->sta_cleanup);
#ifdef CONFIG_MAC80211_DEBUGFS
/*
* Make sure the debugfs adding work isn't pending after this
* because we're about to be destroyed. It doesn't matter
* whether it ran or not since we're going to flush all STAs
* anyway.
*/
cancel_work_sync(&local->sta_debugfs_add);
#endif
sta_info_flush(local, NULL);
}
/**
* sta_info_flush - flush matching STA entries from the STA table
*
* Returns the number of removed STA entries.
*
* @local: local interface data
* @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
*/
int sta_info_flush(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata)
{
struct sta_info *sta, *tmp;
LIST_HEAD(tmp_list);
int ret = 0;
unsigned long flags;
might_sleep();
spin_lock_irqsave(&local->sta_lock, flags);
list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
if (!sdata || sdata == sta->sdata) {
__sta_info_unlink(&sta);
if (sta) {
list_add_tail(&sta->list, &tmp_list);
ret++;
}
}
}
spin_unlock_irqrestore(&local->sta_lock, flags);
list_for_each_entry_safe(sta, tmp, &tmp_list, list)
sta_info_destroy(sta);
return ret;
}
void ieee80211_sta_expire(struct ieee80211_sub_if_data *sdata,
unsigned long exp_time)
{
struct ieee80211_local *local = sdata->local;
struct sta_info *sta, *tmp;
LIST_HEAD(tmp_list);
unsigned long flags;
spin_lock_irqsave(&local->sta_lock, flags);
list_for_each_entry_safe(sta, tmp, &local->sta_list, list)
if (time_after(jiffies, sta->last_rx + exp_time)) {
#ifdef CONFIG_MAC80211_IBSS_DEBUG
printk(KERN_DEBUG "%s: expiring inactive STA %pM\n",
sdata->dev->name, sta->sta.addr);
#endif
__sta_info_unlink(&sta);
if (sta)
list_add(&sta->list, &tmp_list);
}
spin_unlock_irqrestore(&local->sta_lock, flags);
list_for_each_entry_safe(sta, tmp, &tmp_list, list)
sta_info_destroy(sta);
}
struct ieee80211_sta *ieee80211_find_sta(struct ieee80211_hw *hw,
const u8 *addr)
{
struct sta_info *sta = sta_info_get(hw_to_local(hw), addr);
if (!sta)
return NULL;
return &sta->sta;
}
EXPORT_SYMBOL(ieee80211_find_sta);
