linux/net/mac80211/sta_info.c
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   1/*
   2 * Copyright 2002-2005, Instant802 Networks, Inc.
   3 * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   4 *
   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.
   8 */
   9
  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>
  19
  20#include <net/mac80211.h>
  21#include "ieee80211_i.h"
  22#include "rate.h"
  23#include "sta_info.h"
  24#include "debugfs_sta.h"
  25#include "mesh.h"
  26
  27/**
  28 * DOC: STA information lifetime rules
  29 *
  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.
  33 *
  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. Note that the
  40 * caller may not do much with the STA info before inserting it, in particular,
  41 * it may not start any mesh peer link management or add encryption keys.
  42 *
  43 * When the insertion fails (sta_info_insert()) returns non-zero), the
  44 * structure will have been freed by sta_info_insert()!
  45 *
  46 * Because there are debugfs entries for each station, and adding those
  47 * must be able to sleep, it is also possible to "pin" a station entry,
  48 * that means it can be removed from the hash table but not be freed.
  49 * See the comment in __sta_info_unlink() for more information, this is
  50 * an internal capability only.
  51 *
  52 * In order to remove a STA info structure, the caller needs to first
  53 * unlink it (sta_info_unlink()) from the list and hash tables and
  54 * then destroy it; sta_info_destroy() will wait for an RCU grace period
  55 * to elapse before actually freeing it. Due to the pinning and the
  56 * possibility of multiple callers trying to remove the same STA info at
  57 * the same time, sta_info_unlink() can clear the STA info pointer it is
  58 * passed to indicate that the STA info is owned by somebody else now.
  59 *
  60 * If sta_info_unlink() did not clear the pointer then the caller owns
  61 * the STA info structure now and is responsible of destroying it with
  62 * a call to sta_info_destroy().
  63 *
  64 * In all other cases, there is no concept of ownership on a STA entry,
  65 * each structure is owned by the global hash table/list until it is
  66 * removed. All users of the structure need to be RCU protected so that
  67 * the structure won't be freed before they are done using it.
  68 */
  69
  70/* Caller must hold local->sta_lock */
  71static int sta_info_hash_del(struct ieee80211_local *local,
  72                             struct sta_info *sta)
  73{
  74        struct sta_info *s;
  75
  76        s = local->sta_hash[STA_HASH(sta->sta.addr)];
  77        if (!s)
  78                return -ENOENT;
  79        if (s == sta) {
  80                rcu_assign_pointer(local->sta_hash[STA_HASH(sta->sta.addr)],
  81                                   s->hnext);
  82                return 0;
  83        }
  84
  85        while (s->hnext && s->hnext != sta)
  86                s = s->hnext;
  87        if (s->hnext) {
  88                rcu_assign_pointer(s->hnext, sta->hnext);
  89                return 0;
  90        }
  91
  92        return -ENOENT;
  93}
  94
  95/* protected by RCU */
  96struct sta_info *sta_info_get(struct ieee80211_local *local, const u8 *addr)
  97{
  98        struct sta_info *sta;
  99
 100        sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
 101        while (sta) {
 102                if (memcmp(sta->sta.addr, addr, ETH_ALEN) == 0)
 103                        break;
 104                sta = rcu_dereference(sta->hnext);
 105        }
 106        return sta;
 107}
 108
 109struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx,
 110                                     struct net_device *dev)
 111{
 112        struct sta_info *sta;
 113        int i = 0;
 114
 115        list_for_each_entry_rcu(sta, &local->sta_list, list) {
 116                if (dev && dev != sta->sdata->dev)
 117                        continue;
 118                if (i < idx) {
 119                        ++i;
 120                        continue;
 121                }
 122                return sta;
 123        }
 124
 125        return NULL;
 126}
 127
 128/**
 129 * __sta_info_free - internal STA free helper
 130 *
 131 * @local: pointer to the global information
 132 * @sta: STA info to free
 133 *
 134 * This function must undo everything done by sta_info_alloc()
 135 * that may happen before sta_info_insert().
 136 */
 137static void __sta_info_free(struct ieee80211_local *local,
 138                            struct sta_info *sta)
 139{
 140        rate_control_free_sta(sta);
 141        rate_control_put(sta->rate_ctrl);
 142
 143#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 144        printk(KERN_DEBUG "%s: Destroyed STA %pM\n",
 145               wiphy_name(local->hw.wiphy), sta->sta.addr);
 146#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
 147
 148        kfree(sta);
 149}
 150
 151void sta_info_destroy(struct sta_info *sta)
 152{
 153        struct ieee80211_local *local;
 154        struct sk_buff *skb;
 155        int i;
 156
 157        might_sleep();
 158
 159        if (!sta)
 160                return;
 161
 162        local = sta->local;
 163
 164        rate_control_remove_sta_debugfs(sta);
 165        ieee80211_sta_debugfs_remove(sta);
 166
 167#ifdef CONFIG_MAC80211_MESH
 168        if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 169                mesh_plink_deactivate(sta);
 170#endif
 171
 172        /*
 173         * We have only unlinked the key, and actually destroying it
 174         * may mean it is removed from hardware which requires that
 175         * the key->sta pointer is still valid, so flush the key todo
 176         * list here.
 177         *
 178         * ieee80211_key_todo() will synchronize_rcu() so after this
 179         * nothing can reference this sta struct any more.
 180         */
 181        ieee80211_key_todo();
 182
 183#ifdef CONFIG_MAC80211_MESH
 184        if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 185                del_timer_sync(&sta->plink_timer);
 186#endif
 187
 188        while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
 189                local->total_ps_buffered--;
 190                dev_kfree_skb_any(skb);
 191        }
 192
 193        while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
 194                dev_kfree_skb_any(skb);
 195
 196        for (i = 0; i <  STA_TID_NUM; i++) {
 197                struct tid_ampdu_rx *tid_rx;
 198                struct tid_ampdu_tx *tid_tx;
 199
 200                spin_lock_bh(&sta->lock);
 201                tid_rx = sta->ampdu_mlme.tid_rx[i];
 202                /* Make sure timer won't free the tid_rx struct, see below */
 203                if (tid_rx)
 204                        tid_rx->shutdown = true;
 205
 206                spin_unlock_bh(&sta->lock);
 207
 208                /*
 209                 * Outside spinlock - shutdown is true now so that the timer
 210                 * won't free tid_rx, we have to do that now. Can't let the
 211                 * timer do it because we have to sync the timer outside the
 212                 * lock that it takes itself.
 213                 */
 214                if (tid_rx) {
 215                        del_timer_sync(&tid_rx->session_timer);
 216                        kfree(tid_rx);
 217                }
 218
 219                /*
 220                 * No need to do such complications for TX agg sessions, the
 221                 * path leading to freeing the tid_tx struct goes via a call
 222                 * from the driver, and thus needs to look up the sta struct
 223                 * again, which cannot be found when we get here. Hence, we
 224                 * just need to delete the timer and free the aggregation
 225                 * info; we won't be telling the peer about it then but that
 226                 * doesn't matter if we're not talking to it again anyway.
 227                 */
 228                tid_tx = sta->ampdu_mlme.tid_tx[i];
 229                if (tid_tx) {
 230                        del_timer_sync(&tid_tx->addba_resp_timer);
 231                        /*
 232                         * STA removed while aggregation session being
 233                         * started? Bit odd, but purge frames anyway.
 234                         */
 235                        skb_queue_purge(&tid_tx->pending);
 236                        kfree(tid_tx);
 237                }
 238        }
 239
 240        __sta_info_free(local, sta);
 241}
 242
 243
 244/* Caller must hold local->sta_lock */
 245static void sta_info_hash_add(struct ieee80211_local *local,
 246                              struct sta_info *sta)
 247{
 248        sta->hnext = local->sta_hash[STA_HASH(sta->sta.addr)];
 249        rcu_assign_pointer(local->sta_hash[STA_HASH(sta->sta.addr)], sta);
 250}
 251
 252struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
 253                                u8 *addr, gfp_t gfp)
 254{
 255        struct ieee80211_local *local = sdata->local;
 256        struct sta_info *sta;
 257        int i;
 258
 259        sta = kzalloc(sizeof(*sta) + local->hw.sta_data_size, gfp);
 260        if (!sta)
 261                return NULL;
 262
 263        spin_lock_init(&sta->lock);
 264        spin_lock_init(&sta->flaglock);
 265
 266        memcpy(sta->sta.addr, addr, ETH_ALEN);
 267        sta->local = local;
 268        sta->sdata = sdata;
 269
 270        sta->rate_ctrl = rate_control_get(local->rate_ctrl);
 271        sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
 272                                                     &sta->sta, gfp);
 273        if (!sta->rate_ctrl_priv) {
 274                rate_control_put(sta->rate_ctrl);
 275                kfree(sta);
 276                return NULL;
 277        }
 278
 279        for (i = 0; i < STA_TID_NUM; i++) {
 280                /* timer_to_tid must be initialized with identity mapping to
 281                 * enable session_timer's data differentiation. refer to
 282                 * sta_rx_agg_session_timer_expired for useage */
 283                sta->timer_to_tid[i] = i;
 284                /* rx */
 285                sta->ampdu_mlme.tid_state_rx[i] = HT_AGG_STATE_IDLE;
 286                sta->ampdu_mlme.tid_rx[i] = NULL;
 287                /* tx */
 288                sta->ampdu_mlme.tid_state_tx[i] = HT_AGG_STATE_IDLE;
 289                sta->ampdu_mlme.tid_tx[i] = NULL;
 290                sta->ampdu_mlme.addba_req_num[i] = 0;
 291        }
 292        skb_queue_head_init(&sta->ps_tx_buf);
 293        skb_queue_head_init(&sta->tx_filtered);
 294
 295#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 296        printk(KERN_DEBUG "%s: Allocated STA %pM\n",
 297               wiphy_name(local->hw.wiphy), sta->sta.addr);
 298#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
 299
 300#ifdef CONFIG_MAC80211_MESH
 301        sta->plink_state = PLINK_LISTEN;
 302        init_timer(&sta->plink_timer);
 303#endif
 304
 305        return sta;
 306}
 307
 308int sta_info_insert(struct sta_info *sta)
 309{
 310        struct ieee80211_local *local = sta->local;
 311        struct ieee80211_sub_if_data *sdata = sta->sdata;
 312        unsigned long flags;
 313        int err = 0;
 314
 315        /*
 316         * Can't be a WARN_ON because it can be triggered through a race:
 317         * something inserts a STA (on one CPU) without holding the RTNL
 318         * and another CPU turns off the net device.
 319         */
 320        if (unlikely(!netif_running(sdata->dev))) {
 321                err = -ENETDOWN;
 322                goto out_free;
 323        }
 324
 325        if (WARN_ON(compare_ether_addr(sta->sta.addr, sdata->dev->dev_addr) == 0 ||
 326                    is_multicast_ether_addr(sta->sta.addr))) {
 327                err = -EINVAL;
 328                goto out_free;
 329        }
 330
 331        spin_lock_irqsave(&local->sta_lock, flags);
 332        /* check if STA exists already */
 333        if (sta_info_get(local, sta->sta.addr)) {
 334                spin_unlock_irqrestore(&local->sta_lock, flags);
 335                err = -EEXIST;
 336                goto out_free;
 337        }
 338        list_add(&sta->list, &local->sta_list);
 339        local->num_sta++;
 340        sta_info_hash_add(local, sta);
 341
 342        /* notify driver */
 343        if (local->ops->sta_notify) {
 344                if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
 345                        sdata = container_of(sdata->bss,
 346                                             struct ieee80211_sub_if_data,
 347                                             u.ap);
 348
 349                local->ops->sta_notify(local_to_hw(local), &sdata->vif,
 350                                       STA_NOTIFY_ADD, &sta->sta);
 351        }
 352
 353#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 354        printk(KERN_DEBUG "%s: Inserted STA %pM\n",
 355               wiphy_name(local->hw.wiphy), sta->sta.addr);
 356#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
 357
 358        spin_unlock_irqrestore(&local->sta_lock, flags);
 359
 360#ifdef CONFIG_MAC80211_DEBUGFS
 361        /*
 362         * Debugfs entry adding might sleep, so schedule process
 363         * context task for adding entry for STAs that do not yet
 364         * have one.
 365         * NOTE: due to auto-freeing semantics this may only be done
 366         *       if the insertion is successful!
 367         */
 368        schedule_work(&local->sta_debugfs_add);
 369#endif
 370
 371        if (ieee80211_vif_is_mesh(&sdata->vif))
 372                mesh_accept_plinks_update(sdata);
 373
 374        return 0;
 375 out_free:
 376        BUG_ON(!err);
 377        __sta_info_free(local, sta);
 378        return err;
 379}
 380
 381static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
 382{
 383        /*
 384         * This format has been mandated by the IEEE specifications,
 385         * so this line may not be changed to use the __set_bit() format.
 386         */
 387        bss->tim[aid / 8] |= (1 << (aid % 8));
 388}
 389
 390static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
 391{
 392        /*
 393         * This format has been mandated by the IEEE specifications,
 394         * so this line may not be changed to use the __clear_bit() format.
 395         */
 396        bss->tim[aid / 8] &= ~(1 << (aid % 8));
 397}
 398
 399static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
 400                                   struct sta_info *sta)
 401{
 402        BUG_ON(!bss);
 403
 404        __bss_tim_set(bss, sta->sta.aid);
 405
 406        if (sta->local->ops->set_tim) {
 407                sta->local->tim_in_locked_section = true;
 408                sta->local->ops->set_tim(local_to_hw(sta->local),
 409                                         &sta->sta, true);
 410                sta->local->tim_in_locked_section = false;
 411        }
 412}
 413
 414void sta_info_set_tim_bit(struct sta_info *sta)
 415{
 416        unsigned long flags;
 417
 418        BUG_ON(!sta->sdata->bss);
 419
 420        spin_lock_irqsave(&sta->local->sta_lock, flags);
 421        __sta_info_set_tim_bit(sta->sdata->bss, sta);
 422        spin_unlock_irqrestore(&sta->local->sta_lock, flags);
 423}
 424
 425static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
 426                                     struct sta_info *sta)
 427{
 428        BUG_ON(!bss);
 429
 430        __bss_tim_clear(bss, sta->sta.aid);
 431
 432        if (sta->local->ops->set_tim) {
 433                sta->local->tim_in_locked_section = true;
 434                sta->local->ops->set_tim(local_to_hw(sta->local),
 435                                         &sta->sta, false);
 436                sta->local->tim_in_locked_section = false;
 437        }
 438}
 439
 440void sta_info_clear_tim_bit(struct sta_info *sta)
 441{
 442        unsigned long flags;
 443
 444        BUG_ON(!sta->sdata->bss);
 445
 446        spin_lock_irqsave(&sta->local->sta_lock, flags);
 447        __sta_info_clear_tim_bit(sta->sdata->bss, sta);
 448        spin_unlock_irqrestore(&sta->local->sta_lock, flags);
 449}
 450
 451static void __sta_info_unlink(struct sta_info **sta)
 452{
 453        struct ieee80211_local *local = (*sta)->local;
 454        struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
 455        /*
 456         * pull caller's reference if we're already gone.
 457         */
 458        if (sta_info_hash_del(local, *sta)) {
 459                *sta = NULL;
 460                return;
 461        }
 462
 463        if ((*sta)->key) {
 464                ieee80211_key_free((*sta)->key);
 465                WARN_ON((*sta)->key);
 466        }
 467
 468        list_del(&(*sta)->list);
 469
 470        if (test_and_clear_sta_flags(*sta, WLAN_STA_PS)) {
 471                BUG_ON(!sdata->bss);
 472
 473                atomic_dec(&sdata->bss->num_sta_ps);
 474                __sta_info_clear_tim_bit(sdata->bss, *sta);
 475        }
 476
 477        local->num_sta--;
 478
 479        if (local->ops->sta_notify) {
 480                if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
 481                        sdata = container_of(sdata->bss,
 482                                             struct ieee80211_sub_if_data,
 483                                             u.ap);
 484
 485                local->ops->sta_notify(local_to_hw(local), &sdata->vif,
 486                                       STA_NOTIFY_REMOVE, &(*sta)->sta);
 487        }
 488
 489        if (ieee80211_vif_is_mesh(&sdata->vif)) {
 490                mesh_accept_plinks_update(sdata);
 491#ifdef CONFIG_MAC80211_MESH
 492                del_timer(&(*sta)->plink_timer);
 493#endif
 494        }
 495
 496#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 497        printk(KERN_DEBUG "%s: Removed STA %pM\n",
 498               wiphy_name(local->hw.wiphy), (*sta)->sta.addr);
 499#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
 500
 501        /*
 502         * Finally, pull caller's reference if the STA is pinned by the
 503         * task that is adding the debugfs entries. In that case, we
 504         * leave the STA "to be freed".
 505         *
 506         * The rules are not trivial, but not too complex either:
 507         *  (1) pin_status is only modified under the sta_lock
 508         *  (2) STAs may only be pinned under the RTNL so that
 509         *      sta_info_flush() is guaranteed to actually destroy
 510         *      all STAs that are active for a given interface, this
 511         *      is required for correctness because otherwise we
 512         *      could notify a driver that an interface is going
 513         *      away and only after that (!) notify it about a STA
 514         *      on that interface going away.
 515         *  (3) sta_info_debugfs_add_work() will set the status
 516         *      to PINNED when it found an item that needs a new
 517         *      debugfs directory created. In that case, that item
 518         *      must not be freed although all *RCU* users are done
 519         *      with it. Hence, we tell the caller of _unlink()
 520         *      that the item is already gone (as can happen when
 521         *      two tasks try to unlink/destroy at the same time)
 522         *  (4) We set the pin_status to DESTROY here when we
 523         *      find such an item.
 524         *  (5) sta_info_debugfs_add_work() will reset the pin_status
 525         *      from PINNED to NORMAL when it is done with the item,
 526         *      but will check for DESTROY before resetting it in
 527         *      which case it will free the item.
 528         */
 529        if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
 530                (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
 531                *sta = NULL;
 532                return;
 533        }
 534}
 535
 536void sta_info_unlink(struct sta_info **sta)
 537{
 538        struct ieee80211_local *local = (*sta)->local;
 539        unsigned long flags;
 540
 541        spin_lock_irqsave(&local->sta_lock, flags);
 542        __sta_info_unlink(sta);
 543        spin_unlock_irqrestore(&local->sta_lock, flags);
 544}
 545
 546static inline int sta_info_buffer_expired(struct ieee80211_local *local,
 547                                          struct sta_info *sta,
 548                                          struct sk_buff *skb)
 549{
 550        struct ieee80211_tx_info *info;
 551        int timeout;
 552
 553        if (!skb)
 554                return 0;
 555
 556        info = IEEE80211_SKB_CB(skb);
 557
 558        /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
 559        timeout = (sta->listen_interval * local->hw.conf.beacon_int * 32 /
 560                   15625) * HZ;
 561        if (timeout < STA_TX_BUFFER_EXPIRE)
 562                timeout = STA_TX_BUFFER_EXPIRE;
 563        return time_after(jiffies, info->control.jiffies + timeout);
 564}
 565
 566
 567static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
 568                                             struct sta_info *sta)
 569{
 570        unsigned long flags;
 571        struct sk_buff *skb;
 572        struct ieee80211_sub_if_data *sdata;
 573
 574        if (skb_queue_empty(&sta->ps_tx_buf))
 575                return;
 576
 577        for (;;) {
 578                spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
 579                skb = skb_peek(&sta->ps_tx_buf);
 580                if (sta_info_buffer_expired(local, sta, skb))
 581                        skb = __skb_dequeue(&sta->ps_tx_buf);
 582                else
 583                        skb = NULL;
 584                spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
 585
 586                if (!skb)
 587                        break;
 588
 589                sdata = sta->sdata;
 590                local->total_ps_buffered--;
 591#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
 592                printk(KERN_DEBUG "Buffered frame expired (STA %pM)\n",
 593                       sta->sta.addr);
 594#endif
 595                dev_kfree_skb(skb);
 596
 597                if (skb_queue_empty(&sta->ps_tx_buf))
 598                        sta_info_clear_tim_bit(sta);
 599        }
 600}
 601
 602
 603static void sta_info_cleanup(unsigned long data)
 604{
 605        struct ieee80211_local *local = (struct ieee80211_local *) data;
 606        struct sta_info *sta;
 607
 608        rcu_read_lock();
 609        list_for_each_entry_rcu(sta, &local->sta_list, list)
 610                sta_info_cleanup_expire_buffered(local, sta);
 611        rcu_read_unlock();
 612
 613        local->sta_cleanup.expires =
 614                round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
 615        add_timer(&local->sta_cleanup);
 616}
 617
 618#ifdef CONFIG_MAC80211_DEBUGFS
 619/*
 620 * See comment in __sta_info_unlink,
 621 * caller must hold local->sta_lock.
 622 */
 623static void __sta_info_pin(struct sta_info *sta)
 624{
 625        WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
 626        sta->pin_status = STA_INFO_PIN_STAT_PINNED;
 627}
 628
 629/*
 630 * See comment in __sta_info_unlink, returns sta if it
 631 * needs to be destroyed.
 632 */
 633static struct sta_info *__sta_info_unpin(struct sta_info *sta)
 634{
 635        struct sta_info *ret = NULL;
 636        unsigned long flags;
 637
 638        spin_lock_irqsave(&sta->local->sta_lock, flags);
 639        WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
 640                sta->pin_status != STA_INFO_PIN_STAT_PINNED);
 641        if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
 642                ret = sta;
 643        sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
 644        spin_unlock_irqrestore(&sta->local->sta_lock, flags);
 645
 646        return ret;
 647}
 648
 649static void sta_info_debugfs_add_work(struct work_struct *work)
 650{
 651        struct ieee80211_local *local =
 652                container_of(work, struct ieee80211_local, sta_debugfs_add);
 653        struct sta_info *sta, *tmp;
 654        unsigned long flags;
 655
 656        /* We need to keep the RTNL across the whole pinned status. */
 657        rtnl_lock();
 658        while (1) {
 659                sta = NULL;
 660
 661                spin_lock_irqsave(&local->sta_lock, flags);
 662                list_for_each_entry(tmp, &local->sta_list, list) {
 663                        /*
 664                         * debugfs.add_has_run will be set by
 665                         * ieee80211_sta_debugfs_add regardless
 666                         * of what else it does.
 667                         */
 668                        if (!tmp->debugfs.add_has_run) {
 669                                sta = tmp;
 670                                __sta_info_pin(sta);
 671                                break;
 672                        }
 673                }
 674                spin_unlock_irqrestore(&local->sta_lock, flags);
 675
 676                if (!sta)
 677                        break;
 678
 679                ieee80211_sta_debugfs_add(sta);
 680                rate_control_add_sta_debugfs(sta);
 681
 682                sta = __sta_info_unpin(sta);
 683                sta_info_destroy(sta);
 684        }
 685        rtnl_unlock();
 686}
 687#endif
 688
 689static void __ieee80211_run_pending_flush(struct ieee80211_local *local)
 690{
 691        struct sta_info *sta;
 692        unsigned long flags;
 693
 694        ASSERT_RTNL();
 695
 696        spin_lock_irqsave(&local->sta_lock, flags);
 697        while (!list_empty(&local->sta_flush_list)) {
 698                sta = list_first_entry(&local->sta_flush_list,
 699                                       struct sta_info, list);
 700                list_del(&sta->list);
 701                spin_unlock_irqrestore(&local->sta_lock, flags);
 702                sta_info_destroy(sta);
 703                spin_lock_irqsave(&local->sta_lock, flags);
 704        }
 705        spin_unlock_irqrestore(&local->sta_lock, flags);
 706}
 707
 708static void ieee80211_sta_flush_work(struct work_struct *work)
 709{
 710        struct ieee80211_local *local =
 711                container_of(work, struct ieee80211_local, sta_flush_work);
 712
 713        rtnl_lock();
 714        __ieee80211_run_pending_flush(local);
 715        rtnl_unlock();
 716}
 717
 718void sta_info_init(struct ieee80211_local *local)
 719{
 720        spin_lock_init(&local->sta_lock);
 721        INIT_LIST_HEAD(&local->sta_list);
 722        INIT_LIST_HEAD(&local->sta_flush_list);
 723        INIT_WORK(&local->sta_flush_work, ieee80211_sta_flush_work);
 724
 725        setup_timer(&local->sta_cleanup, sta_info_cleanup,
 726                    (unsigned long)local);
 727        local->sta_cleanup.expires =
 728                round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
 729
 730#ifdef CONFIG_MAC80211_DEBUGFS
 731        INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
 732#endif
 733}
 734
 735int sta_info_start(struct ieee80211_local *local)
 736{
 737        add_timer(&local->sta_cleanup);
 738        return 0;
 739}
 740
 741void sta_info_stop(struct ieee80211_local *local)
 742{
 743        del_timer(&local->sta_cleanup);
 744        cancel_work_sync(&local->sta_flush_work);
 745#ifdef CONFIG_MAC80211_DEBUGFS
 746        /*
 747         * Make sure the debugfs adding work isn't pending after this
 748         * because we're about to be destroyed. It doesn't matter
 749         * whether it ran or not since we're going to flush all STAs
 750         * anyway.
 751         */
 752        cancel_work_sync(&local->sta_debugfs_add);
 753#endif
 754
 755        rtnl_lock();
 756        sta_info_flush(local, NULL);
 757        __ieee80211_run_pending_flush(local);
 758        rtnl_unlock();
 759}
 760
 761/**
 762 * sta_info_flush - flush matching STA entries from the STA table
 763 *
 764 * Returns the number of removed STA entries.
 765 *
 766 * @local: local interface data
 767 * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
 768 */
 769int sta_info_flush(struct ieee80211_local *local,
 770                    struct ieee80211_sub_if_data *sdata)
 771{
 772        struct sta_info *sta, *tmp;
 773        LIST_HEAD(tmp_list);
 774        int ret = 0;
 775        unsigned long flags;
 776
 777        might_sleep();
 778        ASSERT_RTNL();
 779
 780        spin_lock_irqsave(&local->sta_lock, flags);
 781        list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
 782                if (!sdata || sdata == sta->sdata) {
 783                        __sta_info_unlink(&sta);
 784                        if (sta) {
 785                                list_add_tail(&sta->list, &tmp_list);
 786                                ret++;
 787                        }
 788                }
 789        }
 790        spin_unlock_irqrestore(&local->sta_lock, flags);
 791
 792        list_for_each_entry_safe(sta, tmp, &tmp_list, list)
 793                sta_info_destroy(sta);
 794
 795        return ret;
 796}
 797
 798/**
 799 * sta_info_flush_delayed - flush matching STA entries from the STA table
 800 *
 801 * This function unlinks all stations for a given interface and queues
 802 * them for freeing. Note that the workqueue function scheduled here has
 803 * to run before any new keys can be added to the system to avoid set_key()
 804 * callback ordering issues.
 805 *
 806 * @sdata: the interface
 807 */
 808void sta_info_flush_delayed(struct ieee80211_sub_if_data *sdata)
 809{
 810        struct ieee80211_local *local = sdata->local;
 811        struct sta_info *sta, *tmp;
 812        unsigned long flags;
 813        bool work = false;
 814
 815        spin_lock_irqsave(&local->sta_lock, flags);
 816        list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
 817                if (sdata == sta->sdata) {
 818                        __sta_info_unlink(&sta);
 819                        if (sta) {
 820                                list_add_tail(&sta->list,
 821                                              &local->sta_flush_list);
 822                                work = true;
 823                        }
 824                }
 825        }
 826        if (work)
 827                schedule_work(&local->sta_flush_work);
 828        spin_unlock_irqrestore(&local->sta_lock, flags);
 829}
 830
 831void ieee80211_sta_expire(struct ieee80211_sub_if_data *sdata,
 832                          unsigned long exp_time)
 833{
 834        struct ieee80211_local *local = sdata->local;
 835        struct sta_info *sta, *tmp;
 836        LIST_HEAD(tmp_list);
 837        unsigned long flags;
 838
 839        spin_lock_irqsave(&local->sta_lock, flags);
 840        list_for_each_entry_safe(sta, tmp, &local->sta_list, list)
 841                if (time_after(jiffies, sta->last_rx + exp_time)) {
 842#ifdef CONFIG_MAC80211_IBSS_DEBUG
 843                        printk(KERN_DEBUG "%s: expiring inactive STA %pM\n",
 844                               sdata->dev->name, sta->sta.addr);
 845#endif
 846                        __sta_info_unlink(&sta);
 847                        if (sta)
 848                                list_add(&sta->list, &tmp_list);
 849                }
 850        spin_unlock_irqrestore(&local->sta_lock, flags);
 851
 852        list_for_each_entry_safe(sta, tmp, &tmp_list, list)
 853                sta_info_destroy(sta);
 854}
 855
 856struct ieee80211_sta *ieee80211_find_sta(struct ieee80211_hw *hw,
 857                                         const u8 *addr)
 858{
 859        struct sta_info *sta = sta_info_get(hw_to_local(hw), addr);
 860
 861        if (!sta)
 862                return NULL;
 863        return &sta->sta;
 864}
 865EXPORT_SYMBOL(ieee80211_find_sta);
 866