/* * 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()! * * sta entries are added by mac80211 when you establish a link with a * peer. This means different things for the different type of interfaces * we support. For a regular station this mean we add the AP sta when we * receive an assocation response from the AP. For IBSS this occurs when * we receive a probe response or a beacon from target IBSS network. For * WDS we add the sta for the peer imediately upon device open. When using * AP mode we add stations for each respective station upon request from * userspace through nl80211. * * 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); for (i = 0; i < NUM_RX_DATA_QUEUES; i++) sta->last_seq_ctrl[i] = cpu_to_le16(USHORT_MAX); #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->sta_generation++; 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); sdata = sta->sdata; } #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--; local->sta_generation++; 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); sdata = (*sta)->sdata; } 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(); if (local->quiescing) return; 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);