sta_info.c revision 97bff8ecf4e4e26749a67dcfbb7565d8a0f4acb4
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 "ieee80211_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. 40 * 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. 45 * 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. 53 * 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. 58 * 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. 63 */ 64 65/* Caller must hold local->sta_lock */ 66static int sta_info_hash_del(struct ieee80211_local *local, 67 struct sta_info *sta) 68{ 69 struct sta_info *s; 70 71 s = local->sta_hash[STA_HASH(sta->addr)]; 72 if (!s) 73 return -ENOENT; 74 if (s == sta) { 75 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], 76 s->hnext); 77 return 0; 78 } 79 80 while (s->hnext && s->hnext != sta) 81 s = s->hnext; 82 if (s->hnext) { 83 rcu_assign_pointer(s->hnext, sta->hnext); 84 return 0; 85 } 86 87 return -ENOENT; 88} 89 90/* protected by RCU */ 91static struct sta_info *__sta_info_find(struct ieee80211_local *local, 92 u8 *addr) 93{ 94 struct sta_info *sta; 95 96 sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]); 97 while (sta) { 98 if (compare_ether_addr(sta->addr, addr) == 0) 99 break; 100 sta = rcu_dereference(sta->hnext); 101 } 102 return sta; 103} 104 105struct sta_info *sta_info_get(struct ieee80211_local *local, u8 *addr) 106{ 107 return __sta_info_find(local, addr); 108} 109EXPORT_SYMBOL(sta_info_get); 110 111struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx, 112 struct net_device *dev) 113{ 114 struct sta_info *sta; 115 int i = 0; 116 117 list_for_each_entry_rcu(sta, &local->sta_list, list) { 118 if (dev && dev != sta->sdata->dev) 119 continue; 120 if (i < idx) { 121 ++i; 122 continue; 123 } 124 return sta; 125 } 126 127 return NULL; 128} 129 130void sta_info_destroy(struct sta_info *sta) 131{ 132 struct ieee80211_local *local; 133 struct sk_buff *skb; 134 int i; 135 DECLARE_MAC_BUF(mbuf); 136 137 ASSERT_RTNL(); 138 might_sleep(); 139 140 if (!sta) 141 return; 142 143 local = sta->local; 144 145 rate_control_remove_sta_debugfs(sta); 146 ieee80211_sta_debugfs_remove(sta); 147 148#ifdef CONFIG_MAC80211_MESH 149 if (ieee80211_vif_is_mesh(&sta->sdata->vif)) 150 mesh_plink_deactivate(sta); 151#endif 152 153 /* 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! 157 */ 158 ieee80211_key_free(sta->key); 159 WARN_ON(sta->key); 160 161#ifdef CONFIG_MAC80211_MESH 162 if (ieee80211_vif_is_mesh(&sta->sdata->vif)) 163 del_timer_sync(&sta->plink_timer); 164#endif 165 166 while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) { 167 local->total_ps_buffered--; 168 dev_kfree_skb_any(skb); 169 } 170 171 while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL) 172 dev_kfree_skb_any(skb); 173 174 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); 183 } 184 185 rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv); 186 rate_control_put(sta->rate_ctrl); 187 188#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 */ 192 193 kfree(sta); 194} 195 196 197/* Caller must hold local->sta_lock */ 198static void sta_info_hash_add(struct ieee80211_local *local, 199 struct sta_info *sta) 200{ 201 sta->hnext = local->sta_hash[STA_HASH(sta->addr)]; 202 rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], sta); 203} 204 205struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata, 206 u8 *addr, gfp_t gfp) 207{ 208 struct ieee80211_local *local = sdata->local; 209 struct sta_info *sta; 210 int i; 211 DECLARE_MAC_BUF(mbuf); 212 213 sta = kzalloc(sizeof(*sta), gfp); 214 if (!sta) 215 return NULL; 216 217 memcpy(sta->addr, addr, ETH_ALEN); 218 sta->local = local; 219 sta->sdata = sdata; 220 221 sta->rate_ctrl = rate_control_get(local->rate_ctrl); 222 sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl, 223 gfp); 224 if (!sta->rate_ctrl_priv) { 225 rate_control_put(sta->rate_ctrl); 226 kfree(sta); 227 return NULL; 228 } 229 230 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; 239 /* rx */ 240 sta->ampdu_mlme.tid_state_rx[i] = HT_AGG_STATE_IDLE; 241 sta->ampdu_mlme.tid_rx[i] = NULL; 242 /* tx */ 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; 246 } 247 skb_queue_head_init(&sta->ps_tx_buf); 248 skb_queue_head_init(&sta->tx_filtered); 249 250#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 */ 254 255#ifdef CONFIG_MAC80211_MESH 256 sta->plink_state = PLINK_LISTEN; 257 spin_lock_init(&sta->plink_lock); 258 init_timer(&sta->plink_timer); 259#endif 260 261 return sta; 262} 263 264int sta_info_insert(struct sta_info *sta) 265{ 266 struct ieee80211_local *local = sta->local; 267 struct ieee80211_sub_if_data *sdata = sta->sdata; 268 unsigned long flags; 269 DECLARE_MAC_BUF(mac); 270 271 /* 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. 275 */ 276 if (unlikely(!netif_running(sdata->dev))) 277 return -ENETDOWN; 278 279 if (WARN_ON(compare_ether_addr(sta->addr, sdata->dev->dev_addr) == 0)) 280 return -EINVAL; 281 282 if (WARN_ON(is_multicast_ether_addr(sta->addr))) 283 return -EINVAL; 284 285 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); 289 return -EEXIST; 290 } 291 list_add(&sta->list, &local->sta_list); 292 local->num_sta++; 293 sta_info_hash_add(local, sta); 294 295 /* notify driver */ 296 if (local->ops->sta_notify) { 297 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN) 298 sdata = sdata->u.vlan.ap; 299 300 local->ops->sta_notify(local_to_hw(local), &sdata->vif, 301 STA_NOTIFY_ADD, sta->addr); 302 } 303 304#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 */ 308 309 spin_unlock_irqrestore(&local->sta_lock, flags); 310 311#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 314 * have one. */ 315 queue_work(local->hw.workqueue, &local->sta_debugfs_add); 316#endif 317 318 if (ieee80211_vif_is_mesh(&sdata->vif)) 319 mesh_accept_plinks_update(sdata); 320 321 return 0; 322} 323 324static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid) 325{ 326 /* 327 * This format has been mandated by the IEEE specifications, 328 * so this line may not be changed to use the __set_bit() format. 329 */ 330 bss->tim[aid / 8] |= (1 << (aid % 8)); 331} 332 333static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid) 334{ 335 /* 336 * This format has been mandated by the IEEE specifications, 337 * so this line may not be changed to use the __clear_bit() format. 338 */ 339 bss->tim[aid / 8] &= ~(1 << (aid % 8)); 340} 341 342static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss, 343 struct sta_info *sta) 344{ 345 if (bss) 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; 351 } 352} 353 354void sta_info_set_tim_bit(struct sta_info *sta) 355{ 356 unsigned long flags; 357 358 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); 361} 362 363static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss, 364 struct sta_info *sta) 365{ 366 if (bss) 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; 372 } 373} 374 375void sta_info_clear_tim_bit(struct sta_info *sta) 376{ 377 unsigned long flags; 378 379 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); 382} 383 384/* 385 * See comment in __sta_info_unlink, 386 * caller must hold local->sta_lock. 387 */ 388static void __sta_info_pin(struct sta_info *sta) 389{ 390 WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL); 391 sta->pin_status = STA_INFO_PIN_STAT_PINNED; 392} 393 394/* 395 * See comment in __sta_info_unlink, returns sta if it 396 * needs to be destroyed. 397 */ 398static struct sta_info *__sta_info_unpin(struct sta_info *sta) 399{ 400 struct sta_info *ret = NULL; 401 unsigned long flags; 402 403 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) 407 ret = sta; 408 sta->pin_status = STA_INFO_PIN_STAT_NORMAL; 409 spin_unlock_irqrestore(&sta->local->sta_lock, flags); 410 411 return ret; 412} 413 414static void __sta_info_unlink(struct sta_info **sta) 415{ 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); 420#endif 421 /* 422 * pull caller's reference if we're already gone. 423 */ 424 if (sta_info_hash_del(local, *sta)) { 425 *sta = NULL; 426 return; 427 } 428 429 /* 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". 433 * 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 444 * find such an item. 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. 449 */ 450 if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) { 451 (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY; 452 *sta = NULL; 453 return; 454 } 455 456 list_del(&(*sta)->list); 457 458 if ((*sta)->flags & WLAN_STA_PS) { 459 (*sta)->flags &= ~WLAN_STA_PS; 460 if (sdata->bss) 461 atomic_dec(&sdata->bss->num_sta_ps); 462 __sta_info_clear_tim_bit(sdata->bss, *sta); 463 } 464 465 local->num_sta--; 466 467 if (local->ops->sta_notify) { 468 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN) 469 sdata = sdata->u.vlan.ap; 470 471 local->ops->sta_notify(local_to_hw(local), &sdata->vif, 472 STA_NOTIFY_REMOVE, (*sta)->addr); 473 } 474 475 if (ieee80211_vif_is_mesh(&sdata->vif)) { 476 mesh_accept_plinks_update(sdata); 477#ifdef CONFIG_MAC80211_MESH 478 del_timer(&(*sta)->plink_timer); 479#endif 480 } 481 482#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 */ 486} 487 488void sta_info_unlink(struct sta_info **sta) 489{ 490 struct ieee80211_local *local = (*sta)->local; 491 unsigned long flags; 492 493 spin_lock_irqsave(&local->sta_lock, flags); 494 __sta_info_unlink(sta); 495 spin_unlock_irqrestore(&local->sta_lock, flags); 496} 497 498static inline int sta_info_buffer_expired(struct ieee80211_local *local, 499 struct sta_info *sta, 500 struct sk_buff *skb) 501{ 502 struct ieee80211_tx_packet_data *pkt_data; 503 int timeout; 504 505 if (!skb) 506 return 0; 507 508 pkt_data = (struct ieee80211_tx_packet_data *) skb->cb; 509 510 /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */ 511 timeout = (sta->listen_interval * local->hw.conf.beacon_int * 32 / 512 15625) * HZ; 513 if (timeout < STA_TX_BUFFER_EXPIRE) 514 timeout = STA_TX_BUFFER_EXPIRE; 515 return time_after(jiffies, pkt_data->jiffies + timeout); 516} 517 518 519static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local, 520 struct sta_info *sta) 521{ 522 unsigned long flags; 523 struct sk_buff *skb; 524 struct ieee80211_sub_if_data *sdata; 525 DECLARE_MAC_BUF(mac); 526 527 if (skb_queue_empty(&sta->ps_tx_buf)) 528 return; 529 530 for (;;) { 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); 535 else 536 skb = NULL; 537 spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags); 538 539 if (!skb) 540 break; 541 542 sdata = sta->sdata; 543 local->total_ps_buffered--; 544 printk(KERN_DEBUG "Buffered frame expired (STA " 545 "%s)\n", print_mac(mac, sta->addr)); 546 dev_kfree_skb(skb); 547 548 if (skb_queue_empty(&sta->ps_tx_buf)) 549 sta_info_clear_tim_bit(sta); 550 } 551} 552 553 554static void sta_info_cleanup(unsigned long data) 555{ 556 struct ieee80211_local *local = (struct ieee80211_local *) data; 557 struct sta_info *sta; 558 559 rcu_read_lock(); 560 list_for_each_entry_rcu(sta, &local->sta_list, list) 561 sta_info_cleanup_expire_buffered(local, sta); 562 rcu_read_unlock(); 563 564 local->sta_cleanup.expires = 565 round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL); 566 add_timer(&local->sta_cleanup); 567} 568 569#ifdef CONFIG_MAC80211_DEBUGFS 570static void sta_info_debugfs_add_work(struct work_struct *work) 571{ 572 struct ieee80211_local *local = 573 container_of(work, struct ieee80211_local, sta_debugfs_add); 574 struct sta_info *sta, *tmp; 575 unsigned long flags; 576 577 while (1) { 578 sta = NULL; 579 580 spin_lock_irqsave(&local->sta_lock, flags); 581 list_for_each_entry(tmp, &local->sta_list, list) { 582 if (!tmp->debugfs.dir) { 583 sta = tmp; 584 __sta_info_pin(sta); 585 break; 586 } 587 } 588 spin_unlock_irqrestore(&local->sta_lock, flags); 589 590 if (!sta) 591 break; 592 593 ieee80211_sta_debugfs_add(sta); 594 rate_control_add_sta_debugfs(sta); 595 596 sta = __sta_info_unpin(sta); 597 598 if (sta) { 599 synchronize_rcu(); 600 sta_info_destroy(sta); 601 } 602 } 603} 604#endif 605 606void sta_info_init(struct ieee80211_local *local) 607{ 608 spin_lock_init(&local->sta_lock); 609 INIT_LIST_HEAD(&local->sta_list); 610 611 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); 615 616#ifdef CONFIG_MAC80211_DEBUGFS 617 INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work); 618#endif 619} 620 621int sta_info_start(struct ieee80211_local *local) 622{ 623 add_timer(&local->sta_cleanup); 624 return 0; 625} 626 627void sta_info_stop(struct ieee80211_local *local) 628{ 629 del_timer(&local->sta_cleanup); 630 sta_info_flush(local, NULL); 631} 632 633/** 634 * sta_info_flush - flush matching STA entries from the STA table 635 * 636 * Returns the number of removed STA entries. 637 * 638 * @local: local interface data 639 * @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs 640 */ 641int sta_info_flush(struct ieee80211_local *local, 642 struct ieee80211_sub_if_data *sdata) 643{ 644 struct sta_info *sta, *tmp; 645 LIST_HEAD(tmp_list); 646 int ret = 0; 647 unsigned long flags; 648 649 might_sleep(); 650 651 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); 655 if (sta) { 656 list_add_tail(&sta->list, &tmp_list); 657 ret++; 658 } 659 } 660 } 661 spin_unlock_irqrestore(&local->sta_lock, flags); 662 663 synchronize_rcu(); 664 665 list_for_each_entry_safe(sta, tmp, &tmp_list, list) 666 sta_info_destroy(sta); 667 668 return ret; 669} 670