net/wireless/scan.c

   1 /*
   2  * cfg80211 scan result handling
   3  *
   4  * Copyright 2008 Johannes Berg <johannes@sipsolutions.net>
   5  * Copyright 2013-2014  Intel Mobile Communications GmbH
   6  * Copyright 2016       Intel Deutschland GmbH
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/slab.h>
  10 #include <linux/module.h>
  11 #include <linux/netdevice.h>
  12 #include <linux/wireless.h>
  13 #include <linux/nl80211.h>
  14 #include <linux/etherdevice.h>
  15 #include <net/arp.h>
  16 #include <net/cfg80211.h>
  17 #include <net/cfg80211-wext.h>
  18 #include <net/iw_handler.h>
  19 #include "core.h"
  20 #include "nl80211.h"
  21 #include "wext-compat.h"
  22 #include "rdev-ops.h"
  23
  24 /**
  25  * DOC: BSS tree/list structure
  26  *
  27  * At the top level, the BSS list is kept in both a list in each
  28  * registered device (@bss_list) as well as an RB-tree for faster
  29  * lookup. In the RB-tree, entries can be looked up using their
  30  * channel, MESHID, MESHCONF (for MBSSes) or channel, BSSID, SSID
  31  * for other BSSes.
  32  *
  33  * Due to the possibility of hidden SSIDs, there's a second level
  34  * structure, the "hidden_list" and "hidden_beacon_bss" pointer.
  35  * The hidden_list connects all BSSes belonging to a single AP
  36  * that has a hidden SSID, and connects beacon and probe response
  37  * entries. For a probe response entry for a hidden SSID, the
  38  * hidden_beacon_bss pointer points to the BSS struct holding the
  39  * beacon's information.
  40  *
  41  * Reference counting is done for all these references except for
  42  * the hidden_list, so that a beacon BSS struct that is otherwise
  43  * not referenced has one reference for being on the bss_list and
  44  * one for each probe response entry that points to it using the
  45  * hidden_beacon_bss pointer. When a BSS struct that has such a
  46  * pointer is get/put, the refcount update is also propagated to
  47  * the referenced struct, this ensure that it cannot get removed
  48  * while somebody is using the probe response version.
  49  *
  50  * Note that the hidden_beacon_bss pointer never changes, due to
  51  * the reference counting. Therefore, no locking is needed for
  52  * it.
  53  *
  54  * Also note that the hidden_beacon_bss pointer is only relevant
  55  * if the driver uses something other than the IEs, e.g. private
  56  * data stored stored in the BSS struct, since the beacon IEs are
  57  * also linked into the probe response struct.
  58  */
  59
  60 /*
  61  * Limit the number of BSS entries stored in mac80211. Each one is
  62  * a bit over 4k at most, so this limits to roughly 4-5M of memory.
  63  * If somebody wants to really attack this though, they'd likely
  64  * use small beacons, and only one type of frame, limiting each of
  65  * the entries to a much smaller size (in order to generate more
  66  * entries in total, so overhead is bigger.)
  67  */
  68 static int bss_entries_limit = 1000;
  69 module_param(bss_entries_limit, int, 0644);
  70 MODULE_PARM_DESC(bss_entries_limit,
  71                  "limit to number of scan BSS entries (per wiphy, default 1000)");
  72
  73 #define IEEE80211_SCAN_RESULT_EXPIRE    (30 * HZ)
  74
  75 static void bss_free(struct cfg80211_internal_bss *bss)
  76 {
  77         struct cfg80211_bss_ies *ies;
  78
  79         if (WARN_ON(atomic_read(&bss->hold)))
  80                 return;
  81
  82         ies = (void *)rcu_access_pointer(bss->pub.beacon_ies);
  83         if (ies && !bss->pub.hidden_beacon_bss)
  84                 kfree_rcu(ies, rcu_head);
  85         ies = (void *)rcu_access_pointer(bss->pub.proberesp_ies);
  86         if (ies)
  87                 kfree_rcu(ies, rcu_head);
  88
  89         /*
  90          * This happens when the module is removed, it doesn't
  91          * really matter any more save for completeness
  92          */
  93         if (!list_empty(&bss->hidden_list))
  94                 list_del(&bss->hidden_list);
  95
  96         kfree(bss);
  97 }
  98
  99 static inline void bss_ref_get(struct cfg80211_registered_device *rdev,
 100                                struct cfg80211_internal_bss *bss)
 101 {
 102         lockdep_assert_held(&rdev->bss_lock);
 103
 104         bss->refcount++;
 105         if (bss->pub.hidden_beacon_bss) {
 106                 bss = container_of(bss->pub.hidden_beacon_bss,
 107                                    struct cfg80211_internal_bss,
 108                                    pub);
 109                 bss->refcount++;
 110         }
 111 }
 112
 113 static inline void bss_ref_put(struct cfg80211_registered_device *rdev,
 114                                struct cfg80211_internal_bss *bss)
 115 {
 116         lockdep_assert_held(&rdev->bss_lock);
 117
 118         if (bss->pub.hidden_beacon_bss) {
 119                 struct cfg80211_internal_bss *hbss;
 120                 hbss = container_of(bss->pub.hidden_beacon_bss,
 121                                     struct cfg80211_internal_bss,
 122                                     pub);
 123                 hbss->refcount--;
 124                 if (hbss->refcount == 0)
 125                         bss_free(hbss);
 126         }
 127         bss->refcount--;
 128         if (bss->refcount == 0)
 129                 bss_free(bss);
 130 }
 131
 132 static bool __cfg80211_unlink_bss(struct cfg80211_registered_device *rdev,
 133                                   struct cfg80211_internal_bss *bss)
 134 {
 135         lockdep_assert_held(&rdev->bss_lock);
 136
 137         if (!list_empty(&bss->hidden_list)) {
 138                 /*
 139                  * don't remove the beacon entry if it has
 140                  * probe responses associated with it
 141                  */
 142                 if (!bss->pub.hidden_beacon_bss)
 143                         return false;
 144                 /*
 145                  * if it's a probe response entry break its
 146                  * link to the other entries in the group
 147                  */
 148                 list_del_init(&bss->hidden_list);
 149         }
 150
 151         list_del_init(&bss->list);
 152         rb_erase(&bss->rbn, &rdev->bss_tree);
 153         rdev->bss_entries--;
 154         WARN_ONCE((rdev->bss_entries == 0) ^ list_empty(&rdev->bss_list),
 155                   "rdev bss entries[%d]/list[empty:%d] corruption\n",
 156                   rdev->bss_entries, list_empty(&rdev->bss_list));
 157         bss_ref_put(rdev, bss);
 158         return true;
 159 }
 160
 161 static void __cfg80211_bss_expire(struct cfg80211_registered_device *rdev,
 162                                   unsigned long expire_time)
 163 {
 164         struct cfg80211_internal_bss *bss, *tmp;
 165         bool expired = false;
 166
 167         lockdep_assert_held(&rdev->bss_lock);
 168
 169         list_for_each_entry_safe(bss, tmp, &rdev->bss_list, list) {
 170                 if (atomic_read(&bss->hold))
 171                         continue;
 172                 if (!time_after(expire_time, bss->ts))
 173                         continue;
 174
 175                 if (__cfg80211_unlink_bss(rdev, bss))
 176                         expired = true;
 177         }
 178
 179         if (expired)
 180                 rdev->bss_generation++;
 181 }
 182
 183 static bool cfg80211_bss_expire_oldest(struct cfg80211_registered_device *rdev)
 184 {
 185         struct cfg80211_internal_bss *bss, *oldest = NULL;
 186         bool ret;
 187
 188         lockdep_assert_held(&rdev->bss_lock);
 189
 190         list_for_each_entry(bss, &rdev->bss_list, list) {
 191                 if (atomic_read(&bss->hold))
 192                         continue;
 193
 194                 if (!list_empty(&bss->hidden_list) &&
 195                     !bss->pub.hidden_beacon_bss)
 196                         continue;
 197
 198                 if (oldest && time_before(oldest->ts, bss->ts))
 199                         continue;
 200                 oldest = bss;
 201         }
 202
 203         if (WARN_ON(!oldest))
 204                 return false;
 205
 206         /*
 207          * The callers make sure to increase rdev->bss_generation if anything
 208          * gets removed (and a new entry added), so there's no need to also do
 209          * it here.
 210          */
 211
 212         ret = __cfg80211_unlink_bss(rdev, oldest);
 213         WARN_ON(!ret);
 214         return ret;
 215 }
 216
 217 void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev,
 218                            bool send_message)
 219 {
 220         struct cfg80211_scan_request *request;
 221         struct wireless_dev *wdev;
 222         struct sk_buff *msg;
 223 #ifdef CONFIG_CFG80211_WEXT
 224         union iwreq_data wrqu;
 225 #endif
 226
 227         ASSERT_RTNL();
 228
 229         if (rdev->scan_msg) {
 230                 nl80211_send_scan_msg(rdev, rdev->scan_msg);
 231                 rdev->scan_msg = NULL;
 232                 return;
 233         }
 234
 235         request = rdev->scan_req;
 236         if (!request)
 237                 return;
 238
 239         wdev = request->wdev;
 240
 241         /*
 242          * This must be before sending the other events!
 243          * Otherwise, wpa_supplicant gets completely confused with
 244          * wext events.
 245          */
 246         if (wdev->netdev)
 247                 cfg80211_sme_scan_done(wdev->netdev);
 248
 249         if (!request->info.aborted &&
 250             request->flags & NL80211_SCAN_FLAG_FLUSH) {
 251                 /* flush entries from previous scans */
 252                 spin_lock_bh(&rdev->bss_lock);
 253                 __cfg80211_bss_expire(rdev, request->scan_start);
 254                 spin_unlock_bh(&rdev->bss_lock);
 255         }
 256
 257         msg = nl80211_build_scan_msg(rdev, wdev, request->info.aborted);
 258
 259 #ifdef CONFIG_CFG80211_WEXT
 260         if (wdev->netdev && !request->info.aborted) {
 261                 memset(&wrqu, 0, sizeof(wrqu));
 262
 263                 wireless_send_event(wdev->netdev, SIOCGIWSCAN, &wrqu, NULL);
 264         }
 265 #endif
 266
 267         if (wdev->netdev)
 268                 dev_put(wdev->netdev);
 269
 270         rdev->scan_req = NULL;
 271         kfree(request);
 272
 273         if (!send_message)
 274                 rdev->scan_msg = msg;
 275         else
 276                 nl80211_send_scan_msg(rdev, msg);
 277 }
 278
 279 void __cfg80211_scan_done(struct work_struct *wk)
 280 {
 281         struct cfg80211_registered_device *rdev;
 282
 283         rdev = container_of(wk, struct cfg80211_registered_device,
 284                             scan_done_wk);
 285
 286         rtnl_lock();
 287         ___cfg80211_scan_done(rdev, true);
 288         rtnl_unlock();
 289 }
 290
 291 void cfg80211_scan_done(struct cfg80211_scan_request *request,
 292                         struct cfg80211_scan_info *info)
 293 {
 294         trace_cfg80211_scan_done(request, info);
 295         WARN_ON(request != wiphy_to_rdev(request->wiphy)->scan_req);
 296
 297         request->info = *info;
 298         request->notified = true;
 299         queue_work(cfg80211_wq, &wiphy_to_rdev(request->wiphy)->scan_done_wk);
 300 }
 301 EXPORT_SYMBOL(cfg80211_scan_done);
 302
 303 void cfg80211_add_sched_scan_req(struct cfg80211_registered_device *rdev,
 304                                  struct cfg80211_sched_scan_request *req)
 305 {
 306         ASSERT_RTNL();
 307
 308         list_add_rcu(&req->list, &rdev->sched_scan_req_list);
 309 }
 310
 311 static void cfg80211_del_sched_scan_req(struct cfg80211_registered_device *rdev,
 312                                         struct cfg80211_sched_scan_request *req)
 313 {
 314         ASSERT_RTNL();
 315
 316         list_del_rcu(&req->list);
 317         kfree_rcu(req, rcu_head);
 318 }
 319
 320 static struct cfg80211_sched_scan_request *
 321 cfg80211_find_sched_scan_req(struct cfg80211_registered_device *rdev, u64 reqid)
 322 {
 323         struct cfg80211_sched_scan_request *pos;
 324
 325         WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_rtnl_is_held());
 326
 327         list_for_each_entry_rcu(pos, &rdev->sched_scan_req_list, list) {
 328                 if (pos->reqid == reqid)
 329                         return pos;
 330         }
 331         return NULL;
 332 }
 333
 334 /*
 335  * Determines if a scheduled scan request can be handled. When a legacy
 336  * scheduled scan is running no other scheduled scan is allowed regardless
 337  * whether the request is for legacy or multi-support scan. When a multi-support
 338  * scheduled scan is running a request for legacy scan is not allowed. In this
 339  * case a request for multi-support scan can be handled if resources are
 340  * available, ie. struct wiphy::max_sched_scan_reqs limit is not yet reached.
 341  */
 342 int cfg80211_sched_scan_req_possible(struct cfg80211_registered_device *rdev,
 343                                      bool want_multi)
 344 {
 345         struct cfg80211_sched_scan_request *pos;
 346         int i = 0;
 347
 348         list_for_each_entry(pos, &rdev->sched_scan_req_list, list) {
 349                 /* request id zero means legacy in progress */
 350                 if (!i && !pos->reqid)
 351                         return -EINPROGRESS;
 352                 i++;
 353         }
 354
 355         if (i) {
 356                 /* no legacy allowed when multi request(s) are active */
 357                 if (!want_multi)
 358                         return -EINPROGRESS;
 359
 360                 /* resource limit reached */
 361                 if (i == rdev->wiphy.max_sched_scan_reqs)
 362                         return -ENOSPC;
 363         }
 364         return 0;
 365 }
 366
 367 void cfg80211_sched_scan_results_wk(struct work_struct *work)
 368 {
 369         struct cfg80211_registered_device *rdev;
 370         struct cfg80211_sched_scan_request *req, *tmp;
 371
 372         rdev = container_of(work, struct cfg80211_registered_device,
 373                            sched_scan_res_wk);
 374
 375         rtnl_lock();
 376         list_for_each_entry_safe(req, tmp, &rdev->sched_scan_req_list, list) {
 377                 if (req->report_results) {
 378                         req->report_results = false;
 379                         if (req->flags & NL80211_SCAN_FLAG_FLUSH) {
 380                                 /* flush entries from previous scans */
 381                                 spin_lock_bh(&rdev->bss_lock);
 382                                 __cfg80211_bss_expire(rdev, req->scan_start);
 383                                 spin_unlock_bh(&rdev->bss_lock);
 384                                 req->scan_start = jiffies;
 385                         }
 386                         nl80211_send_sched_scan(req,
 387                                                 NL80211_CMD_SCHED_SCAN_RESULTS);
 388                 }
 389         }
 390         rtnl_unlock();
 391 }
 392
 393 void cfg80211_sched_scan_results(struct wiphy *wiphy, u64 reqid)
 394 {
 395         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 396         struct cfg80211_sched_scan_request *request;
 397
 398         trace_cfg80211_sched_scan_results(wiphy, reqid);
 399         /* ignore if we're not scanning */
 400
 401         rcu_read_lock();
 402         request = cfg80211_find_sched_scan_req(rdev, reqid);
 403         if (request) {
 404                 request->report_results = true;
 405                 queue_work(cfg80211_wq, &rdev->sched_scan_res_wk);
 406         }
 407         rcu_read_unlock();
 408 }
 409 EXPORT_SYMBOL(cfg80211_sched_scan_results);
 410
 411 void cfg80211_sched_scan_stopped_rtnl(struct wiphy *wiphy, u64 reqid)
 412 {
 413         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 414
 415         ASSERT_RTNL();
 416
 417         trace_cfg80211_sched_scan_stopped(wiphy, reqid);
 418
 419         __cfg80211_stop_sched_scan(rdev, reqid, true);
 420 }
 421 EXPORT_SYMBOL(cfg80211_sched_scan_stopped_rtnl);
 422
 423 void cfg80211_sched_scan_stopped(struct wiphy *wiphy, u64 reqid)
 424 {
 425         rtnl_lock();
 426         cfg80211_sched_scan_stopped_rtnl(wiphy, reqid);
 427         rtnl_unlock();
 428 }
 429 EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
 430
 431 int cfg80211_stop_sched_scan_req(struct cfg80211_registered_device *rdev,
 432                                  struct cfg80211_sched_scan_request *req,
 433                                  bool driver_initiated)
 434 {
 435         ASSERT_RTNL();
 436
 437         if (!driver_initiated) {
 438                 int err = rdev_sched_scan_stop(rdev, req->dev, req->reqid);
 439                 if (err)
 440                         return err;
 441         }
 442
 443         nl80211_send_sched_scan(req, NL80211_CMD_SCHED_SCAN_STOPPED);
 444
 445         cfg80211_del_sched_scan_req(rdev, req);
 446
 447         return 0;
 448 }
 449
 450 int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
 451                                u64 reqid, bool driver_initiated)
 452 {
 453         struct cfg80211_sched_scan_request *sched_scan_req;
 454
 455         ASSERT_RTNL();
 456
 457         sched_scan_req = cfg80211_find_sched_scan_req(rdev, reqid);
 458         if (!sched_scan_req)
 459                 return -ENOENT;
 460
 461         return cfg80211_stop_sched_scan_req(rdev, sched_scan_req,
 462                                             driver_initiated);
 463 }
 464
 465 void cfg80211_bss_age(struct cfg80211_registered_device *rdev,
 466                       unsigned long age_secs)
 467 {
 468         struct cfg80211_internal_bss *bss;
 469         unsigned long age_jiffies = msecs_to_jiffies(age_secs * MSEC_PER_SEC);
 470
 471         spin_lock_bh(&rdev->bss_lock);
 472         list_for_each_entry(bss, &rdev->bss_list, list)
 473                 bss->ts -= age_jiffies;
 474         spin_unlock_bh(&rdev->bss_lock);
 475 }
 476
 477 void cfg80211_bss_expire(struct cfg80211_registered_device *rdev)
 478 {
 479         __cfg80211_bss_expire(rdev, jiffies - IEEE80211_SCAN_RESULT_EXPIRE);
 480 }
 481
 482 const u8 *cfg80211_find_ie_match(u8 eid, const u8 *ies, int len,
 483                                  const u8 *match, int match_len,
 484                                  int match_offset)
 485 {
 486         /* match_offset can't be smaller than 2, unless match_len is
 487          * zero, in which case match_offset must be zero as well.
 488          */
 489         if (WARN_ON((match_len && match_offset < 2) ||
 490                     (!match_len && match_offset)))
 491                 return NULL;
 492
 493         while (len >= 2 && len >= ies[1] + 2) {
 494                 if ((ies[0] == eid) &&
 495                     (ies[1] + 2 >= match_offset + match_len) &&
 496                     !memcmp(ies + match_offset, match, match_len))
 497                         return ies;
 498
 499                 len -= ies[1] + 2;
 500                 ies += ies[1] + 2;
 501         }
 502
 503         return NULL;
 504 }
 505 EXPORT_SYMBOL(cfg80211_find_ie_match);
 506
 507 const u8 *cfg80211_find_vendor_ie(unsigned int oui, int oui_type,
 508                                   const u8 *ies, int len)
 509 {
 510         const u8 *ie;
 511         u8 match[] = { oui >> 16, oui >> 8, oui, oui_type };
 512         int match_len = (oui_type < 0) ? 3 : sizeof(match);
 513
 514         if (WARN_ON(oui_type > 0xff))
 515                 return NULL;
 516
 517         ie = cfg80211_find_ie_match(WLAN_EID_VENDOR_SPECIFIC, ies, len,
 518                                     match, match_len, 2);
 519
 520         if (ie && (ie[1] < 4))
 521                 return NULL;
 522
 523         return ie;
 524 }
 525 EXPORT_SYMBOL(cfg80211_find_vendor_ie);
 526
 527 static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
 528                    const u8 *ssid, size_t ssid_len)
 529 {
 530         const struct cfg80211_bss_ies *ies;
 531         const u8 *ssidie;
 532
 533         if (bssid && !ether_addr_equal(a->bssid, bssid))
 534                 return false;
 535
 536         if (!ssid)
 537                 return true;
 538
 539         ies = rcu_access_pointer(a->ies);
 540         if (!ies)
 541                 return false;
 542         ssidie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 543         if (!ssidie)
 544                 return false;
 545         if (ssidie[1] != ssid_len)
 546                 return false;
 547         return memcmp(ssidie + 2, ssid, ssid_len) == 0;
 548 }
 549
 550 /**
 551  * enum bss_compare_mode - BSS compare mode
 552  * @BSS_CMP_REGULAR: regular compare mode (for insertion and normal find)
 553  * @BSS_CMP_HIDE_ZLEN: find hidden SSID with zero-length mode
 554  * @BSS_CMP_HIDE_NUL: find hidden SSID with NUL-ed out mode
 555  */
 556 enum bss_compare_mode {
 557         BSS_CMP_REGULAR,
 558         BSS_CMP_HIDE_ZLEN,
 559         BSS_CMP_HIDE_NUL,
 560 };
 561
 562 static int cmp_bss(struct cfg80211_bss *a,
 563                    struct cfg80211_bss *b,
 564                    enum bss_compare_mode mode)
 565 {
 566         const struct cfg80211_bss_ies *a_ies, *b_ies;
 567         const u8 *ie1 = NULL;
 568         const u8 *ie2 = NULL;
 569         int i, r;
 570
 571         if (a->channel != b->channel)
 572                 return b->channel->center_freq - a->channel->center_freq;
 573
 574         a_ies = rcu_access_pointer(a->ies);
 575         if (!a_ies)
 576                 return -1;
 577         b_ies = rcu_access_pointer(b->ies);
 578         if (!b_ies)
 579                 return 1;
 580
 581         if (WLAN_CAPABILITY_IS_STA_BSS(a->capability))
 582                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 583                                        a_ies->data, a_ies->len);
 584         if (WLAN_CAPABILITY_IS_STA_BSS(b->capability))
 585                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 586                                        b_ies->data, b_ies->len);
 587         if (ie1 && ie2) {
 588                 int mesh_id_cmp;
 589
 590                 if (ie1[1] == ie2[1])
 591                         mesh_id_cmp = memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 592                 else
 593                         mesh_id_cmp = ie2[1] - ie1[1];
 594
 595                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 596                                        a_ies->data, a_ies->len);
 597                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 598                                        b_ies->data, b_ies->len);
 599                 if (ie1 && ie2) {
 600                         if (mesh_id_cmp)
 601                                 return mesh_id_cmp;
 602                         if (ie1[1] != ie2[1])
 603                                 return ie2[1] - ie1[1];
 604                         return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 605                 }
 606         }
 607
 608         r = memcmp(a->bssid, b->bssid, sizeof(a->bssid));
 609         if (r)
 610                 return r;
 611
 612         ie1 = cfg80211_find_ie(WLAN_EID_SSID, a_ies->data, a_ies->len);
 613         ie2 = cfg80211_find_ie(WLAN_EID_SSID, b_ies->data, b_ies->len);
 614
 615         if (!ie1 && !ie2)
 616                 return 0;
 617
 618         /*
 619          * Note that with "hide_ssid", the function returns a match if
 620          * the already-present BSS ("b") is a hidden SSID beacon for
 621          * the new BSS ("a").
 622          */
 623
 624         /* sort missing IE before (left of) present IE */
 625         if (!ie1)
 626                 return -1;
 627         if (!ie2)
 628                 return 1;
 629
 630         switch (mode) {
 631         case BSS_CMP_HIDE_ZLEN:
 632                 /*
 633                  * In ZLEN mode we assume the BSS entry we're
 634                  * looking for has a zero-length SSID. So if
 635                  * the one we're looking at right now has that,
 636                  * return 0. Otherwise, return the difference
 637                  * in length, but since we're looking for the
 638                  * 0-length it's really equivalent to returning
 639                  * the length of the one we're looking at.
 640                  *
 641                  * No content comparison is needed as we assume
 642                  * the content length is zero.
 643                  */
 644                 return ie2[1];
 645         case BSS_CMP_REGULAR:
 646         default:
 647                 /* sort by length first, then by contents */
 648                 if (ie1[1] != ie2[1])
 649                         return ie2[1] - ie1[1];
 650                 return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 651         case BSS_CMP_HIDE_NUL:
 652                 if (ie1[1] != ie2[1])
 653                         return ie2[1] - ie1[1];
 654                 /* this is equivalent to memcmp(zeroes, ie2 + 2, len) */
 655                 for (i = 0; i < ie2[1]; i++)
 656                         if (ie2[i + 2])
 657                                 return -1;
 658                 return 0;
 659         }
 660 }
 661
 662 static bool cfg80211_bss_type_match(u16 capability,
 663                                     enum nl80211_band band,
 664                                     enum ieee80211_bss_type bss_type)
 665 {
 666         bool ret = true;
 667         u16 mask, val;
 668
 669         if (bss_type == IEEE80211_BSS_TYPE_ANY)
 670                 return ret;
 671
 672         if (band == NL80211_BAND_60GHZ) {
 673                 mask = WLAN_CAPABILITY_DMG_TYPE_MASK;
 674                 switch (bss_type) {
 675                 case IEEE80211_BSS_TYPE_ESS:
 676                         val = WLAN_CAPABILITY_DMG_TYPE_AP;
 677                         break;
 678                 case IEEE80211_BSS_TYPE_PBSS:
 679                         val = WLAN_CAPABILITY_DMG_TYPE_PBSS;
 680                         break;
 681                 case IEEE80211_BSS_TYPE_IBSS:
 682                         val = WLAN_CAPABILITY_DMG_TYPE_IBSS;
 683                         break;
 684                 default:
 685                         return false;
 686                 }
 687         } else {
 688                 mask = WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS;
 689                 switch (bss_type) {
 690                 case IEEE80211_BSS_TYPE_ESS:
 691                         val = WLAN_CAPABILITY_ESS;
 692                         break;
 693                 case IEEE80211_BSS_TYPE_IBSS:
 694                         val = WLAN_CAPABILITY_IBSS;
 695                         break;
 696                 case IEEE80211_BSS_TYPE_MBSS:
 697                         val = 0;
 698                         break;
 699                 default:
 700                         return false;
 701                 }
 702         }
 703
 704         ret = ((capability & mask) == val);
 705         return ret;
 706 }
 707
 708 /* Returned bss is reference counted and must be cleaned up appropriately. */
 709 struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
 710                                       struct ieee80211_channel *channel,
 711                                       const u8 *bssid,
 712                                       const u8 *ssid, size_t ssid_len,
 713                                       enum ieee80211_bss_type bss_type,
 714                                       enum ieee80211_privacy privacy)
 715 {
 716         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 717         struct cfg80211_internal_bss *bss, *res = NULL;
 718         unsigned long now = jiffies;
 719         int bss_privacy;
 720
 721         trace_cfg80211_get_bss(wiphy, channel, bssid, ssid, ssid_len, bss_type,
 722                                privacy);
 723
 724         spin_lock_bh(&rdev->bss_lock);
 725
 726         list_for_each_entry(bss, &rdev->bss_list, list) {
 727                 if (!cfg80211_bss_type_match(bss->pub.capability,
 728                                              bss->pub.channel->band, bss_type))
 729                         continue;
 730
 731                 bss_privacy = (bss->pub.capability & WLAN_CAPABILITY_PRIVACY);
 732                 if ((privacy == IEEE80211_PRIVACY_ON && !bss_privacy) ||
 733                     (privacy == IEEE80211_PRIVACY_OFF && bss_privacy))
 734                         continue;
 735                 if (channel && bss->pub.channel != channel)
 736                         continue;
 737                 if (!is_valid_ether_addr(bss->pub.bssid))
 738                         continue;
 739                 /* Don't get expired BSS structs */
 740                 if (time_after(now, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE) &&
 741                     !atomic_read(&bss->hold))
 742                         continue;
 743                 if (is_bss(&bss->pub, bssid, ssid, ssid_len)) {
 744                         res = bss;
 745                         bss_ref_get(rdev, res);
 746                         break;
 747                 }
 748         }
 749
 750         spin_unlock_bh(&rdev->bss_lock);
 751         if (!res)
 752                 return NULL;
 753         trace_cfg80211_return_bss(&res->pub);
 754         return &res->pub;
 755 }
 756 EXPORT_SYMBOL(cfg80211_get_bss);
 757
 758 static void rb_insert_bss(struct cfg80211_registered_device *rdev,
 759                           struct cfg80211_internal_bss *bss)
 760 {
 761         struct rb_node **p = &rdev->bss_tree.rb_node;
 762         struct rb_node *parent = NULL;
 763         struct cfg80211_internal_bss *tbss;
 764         int cmp;
 765
 766         while (*p) {
 767                 parent = *p;
 768                 tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);
 769
 770                 cmp = cmp_bss(&bss->pub, &tbss->pub, BSS_CMP_REGULAR);
 771
 772                 if (WARN_ON(!cmp)) {
 773                         /* will sort of leak this BSS */
 774                         return;
 775                 }
 776
 777                 if (cmp < 0)
 778                         p = &(*p)->rb_left;
 779                 else
 780                         p = &(*p)->rb_right;
 781         }
 782
 783         rb_link_node(&bss->rbn, parent, p);
 784         rb_insert_color(&bss->rbn, &rdev->bss_tree);
 785 }
 786
 787 static struct cfg80211_internal_bss *
 788 rb_find_bss(struct cfg80211_registered_device *rdev,
 789             struct cfg80211_internal_bss *res,
 790             enum bss_compare_mode mode)
 791 {
 792         struct rb_node *n = rdev->bss_tree.rb_node;
 793         struct cfg80211_internal_bss *bss;
 794         int r;
 795
 796         while (n) {
 797                 bss = rb_entry(n, struct cfg80211_internal_bss, rbn);
 798                 r = cmp_bss(&res->pub, &bss->pub, mode);
 799
 800                 if (r == 0)
 801                         return bss;
 802                 else if (r < 0)
 803                         n = n->rb_left;
 804                 else
 805                         n = n->rb_right;
 806         }
 807
 808         return NULL;
 809 }
 810
 811 static bool cfg80211_combine_bsses(struct cfg80211_registered_device *rdev,
 812                                    struct cfg80211_internal_bss *new)
 813 {
 814         const struct cfg80211_bss_ies *ies;
 815         struct cfg80211_internal_bss *bss;
 816         const u8 *ie;
 817         int i, ssidlen;
 818         u8 fold = 0;
 819         u32 n_entries = 0;
 820
 821         ies = rcu_access_pointer(new->pub.beacon_ies);
 822         if (WARN_ON(!ies))
 823                 return false;
 824
 825         ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 826         if (!ie) {
 827                 /* nothing to do */
 828                 return true;
 829         }
 830
 831         ssidlen = ie[1];
 832         for (i = 0; i < ssidlen; i++)
 833                 fold |= ie[2 + i];
 834
 835         if (fold) {
 836                 /* not a hidden SSID */
 837                 return true;
 838         }
 839
 840         /* This is the bad part ... */
 841
 842         list_for_each_entry(bss, &rdev->bss_list, list) {
 843                 /*
 844                  * we're iterating all the entries anyway, so take the
 845                  * opportunity to validate the list length accounting
 846                  */
 847                 n_entries++;
 848
 849                 if (!ether_addr_equal(bss->pub.bssid, new->pub.bssid))
 850                         continue;
 851                 if (bss->pub.channel != new->pub.channel)
 852                         continue;
 853                 if (bss->pub.scan_width != new->pub.scan_width)
 854                         continue;
 855                 if (rcu_access_pointer(bss->pub.beacon_ies))
 856                         continue;
 857                 ies = rcu_access_pointer(bss->pub.ies);
 858                 if (!ies)
 859                         continue;
 860                 ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 861                 if (!ie)
 862                         continue;
 863                 if (ssidlen && ie[1] != ssidlen)
 864                         continue;
 865                 if (WARN_ON_ONCE(bss->pub.hidden_beacon_bss))
 866                         continue;
 867                 if (WARN_ON_ONCE(!list_empty(&bss->hidden_list)))
 868                         list_del(&bss->hidden_list);
 869                 /* combine them */
 870                 list_add(&bss->hidden_list, &new->hidden_list);
 871                 bss->pub.hidden_beacon_bss = &new->pub;
 872                 new->refcount += bss->refcount;
 873                 rcu_assign_pointer(bss->pub.beacon_ies,
 874                                    new->pub.beacon_ies);
 875         }
 876
 877         WARN_ONCE(n_entries != rdev->bss_entries,
 878                   "rdev bss entries[%d]/list[len:%d] corruption\n",
 879                   rdev->bss_entries, n_entries);
 880
 881         return true;
 882 }
 883
 884 /* Returned bss is reference counted and must be cleaned up appropriately. */
 885 static struct cfg80211_internal_bss *
 886 cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 887                     struct cfg80211_internal_bss *tmp,
 888                     bool signal_valid)
 889 {
 890         struct cfg80211_internal_bss *found = NULL;
 891
 892         if (WARN_ON(!tmp->pub.channel))
 893                 return NULL;
 894
 895         tmp->ts = jiffies;
 896
 897         spin_lock_bh(&rdev->bss_lock);
 898
 899         if (WARN_ON(!rcu_access_pointer(tmp->pub.ies))) {
 900                 spin_unlock_bh(&rdev->bss_lock);
 901                 return NULL;
 902         }
 903
 904         found = rb_find_bss(rdev, tmp, BSS_CMP_REGULAR);
 905
 906         if (found) {
 907                 /* Update IEs */
 908                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
 909                         const struct cfg80211_bss_ies *old;
 910
 911                         old = rcu_access_pointer(found->pub.proberesp_ies);
 912
 913                         rcu_assign_pointer(found->pub.proberesp_ies,
 914                                            tmp->pub.proberesp_ies);
 915                         /* Override possible earlier Beacon frame IEs */
 916                         rcu_assign_pointer(found->pub.ies,
 917                                            tmp->pub.proberesp_ies);
 918                         if (old)
 919                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 920                                           rcu_head);
 921                 } else if (rcu_access_pointer(tmp->pub.beacon_ies)) {
 922                         const struct cfg80211_bss_ies *old;
 923                         struct cfg80211_internal_bss *bss;
 924
 925                         if (found->pub.hidden_beacon_bss &&
 926                             !list_empty(&found->hidden_list)) {
 927                                 const struct cfg80211_bss_ies *f;
 928
 929                                 /*
 930                                  * The found BSS struct is one of the probe
 931                                  * response members of a group, but we're
 932                                  * receiving a beacon (beacon_ies in the tmp
 933                                  * bss is used). This can only mean that the
 934                                  * AP changed its beacon from not having an
 935                                  * SSID to showing it, which is confusing so
 936                                  * drop this information.
 937                                  */
 938
 939                                 f = rcu_access_pointer(tmp->pub.beacon_ies);
 940                                 kfree_rcu((struct cfg80211_bss_ies *)f,
 941                                           rcu_head);
 942                                 goto drop;
 943                         }
 944
 945                         old = rcu_access_pointer(found->pub.beacon_ies);
 946
 947                         rcu_assign_pointer(found->pub.beacon_ies,
 948                                            tmp->pub.beacon_ies);
 949
 950                         /* Override IEs if they were from a beacon before */
 951                         if (old == rcu_access_pointer(found->pub.ies))
 952                                 rcu_assign_pointer(found->pub.ies,
 953                                                    tmp->pub.beacon_ies);
 954
 955                         /* Assign beacon IEs to all sub entries */
 956                         list_for_each_entry(bss, &found->hidden_list,
 957                                             hidden_list) {
 958                                 const struct cfg80211_bss_ies *ies;
 959
 960                                 ies = rcu_access_pointer(bss->pub.beacon_ies);
 961                                 WARN_ON(ies != old);
 962
 963                                 rcu_assign_pointer(bss->pub.beacon_ies,
 964                                                    tmp->pub.beacon_ies);
 965                         }
 966
 967                         if (old)
 968                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 969                                           rcu_head);
 970                 }
 971
 972                 found->pub.beacon_interval = tmp->pub.beacon_interval;
 973                 /*
 974                  * don't update the signal if beacon was heard on
 975                  * adjacent channel.
 976                  */
 977                 if (signal_valid)
 978                         found->pub.signal = tmp->pub.signal;
 979                 found->pub.capability = tmp->pub.capability;
 980                 found->ts = tmp->ts;
 981                 found->ts_boottime = tmp->ts_boottime;
 982                 found->parent_tsf = tmp->parent_tsf;
 983                 ether_addr_copy(found->parent_bssid, tmp->parent_bssid);
 984         } else {
 985                 struct cfg80211_internal_bss *new;
 986                 struct cfg80211_internal_bss *hidden;
 987                 struct cfg80211_bss_ies *ies;
 988
 989                 /*
 990                  * create a copy -- the "res" variable that is passed in
 991                  * is allocated on the stack since it's not needed in the
 992                  * more common case of an update
 993                  */
 994                 new = kzalloc(sizeof(*new) + rdev->wiphy.bss_priv_size,
 995                               GFP_ATOMIC);
 996                 if (!new) {
 997                         ies = (void *)rcu_dereference(tmp->pub.beacon_ies);
 998                         if (ies)
 999                                 kfree_rcu(ies, rcu_head);
1000                         ies = (void *)rcu_dereference(tmp->pub.proberesp_ies);
1001                         if (ies)
1002                                 kfree_rcu(ies, rcu_head);
1003                         goto drop;
1004                 }
1005                 memcpy(new, tmp, sizeof(*new));
1006                 new->refcount = 1;
1007                 INIT_LIST_HEAD(&new->hidden_list);
1008
1009                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
1010                         hidden = rb_find_bss(rdev, tmp, BSS_CMP_HIDE_ZLEN);
1011                         if (!hidden)
1012                                 hidden = rb_find_bss(rdev, tmp,
1013                                                      BSS_CMP_HIDE_NUL);
1014                         if (hidden) {
1015                                 new->pub.hidden_beacon_bss = &hidden->pub;
1016                                 list_add(&new->hidden_list,
1017                                          &hidden->hidden_list);
1018                                 hidden->refcount++;
1019                                 rcu_assign_pointer(new->pub.beacon_ies,
1020                                                    hidden->pub.beacon_ies);
1021                         }
1022                 } else {
1023                         /*
1024                          * Ok so we found a beacon, and don't have an entry. If
1025                          * it's a beacon with hidden SSID, we might be in for an
1026                          * expensive search for any probe responses that should
1027                          * be grouped with this beacon for updates ...
1028                          */
1029                         if (!cfg80211_combine_bsses(rdev, new)) {
1030                                 kfree(new);
1031                                 goto drop;
1032                         }
1033                 }
1034
1035                 if (rdev->bss_entries >= bss_entries_limit &&
1036                     !cfg80211_bss_expire_oldest(rdev)) {
1037                         kfree(new);
1038                         goto drop;
1039                 }
1040
1041                 list_add_tail(&new->list, &rdev->bss_list);
1042                 rdev->bss_entries++;
1043                 rb_insert_bss(rdev, new);
1044                 found = new;
1045         }
1046
1047         rdev->bss_generation++;
1048         bss_ref_get(rdev, found);
1049         spin_unlock_bh(&rdev->bss_lock);
1050
1051         return found;
1052  drop:
1053         spin_unlock_bh(&rdev->bss_lock);
1054         return NULL;
1055 }
1056
1057 static struct ieee80211_channel *
1058 cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
1059                          struct ieee80211_channel *channel)
1060 {
1061         const u8 *tmp;
1062         u32 freq;
1063         int channel_number = -1;
1064
1065         tmp = cfg80211_find_ie(WLAN_EID_DS_PARAMS, ie, ielen);
1066         if (tmp && tmp[1] == 1) {
1067                 channel_number = tmp[2];
1068         } else {
1069                 tmp = cfg80211_find_ie(WLAN_EID_HT_OPERATION, ie, ielen);
1070                 if (tmp && tmp[1] >= sizeof(struct ieee80211_ht_operation)) {
1071                         struct ieee80211_ht_operation *htop = (void *)(tmp + 2);
1072
1073                         channel_number = htop->primary_chan;
1074                 }
1075         }
1076
1077         if (channel_number < 0)
1078                 return channel;
1079
1080         freq = ieee80211_channel_to_frequency(channel_number, channel->band);
1081         channel = ieee80211_get_channel(wiphy, freq);
1082         if (!channel)
1083                 return NULL;
1084         if (channel->flags & IEEE80211_CHAN_DISABLED)
1085                 return NULL;
1086         return channel;
1087 }
1088
1089 /* Returned bss is reference counted and must be cleaned up appropriately. */
1090 struct cfg80211_bss *
1091 cfg80211_inform_bss_data(struct wiphy *wiphy,
1092                          struct cfg80211_inform_bss *data,
1093                          enum cfg80211_bss_frame_type ftype,
1094                          const u8 *bssid, u64 tsf, u16 capability,
1095                          u16 beacon_interval, const u8 *ie, size_t ielen,
1096                          gfp_t gfp)
1097 {
1098         struct cfg80211_bss_ies *ies;
1099         struct ieee80211_channel *channel;
1100         struct cfg80211_internal_bss tmp = {}, *res;
1101         int bss_type;
1102         bool signal_valid;
1103
1104         if (WARN_ON(!wiphy))
1105                 return NULL;
1106
1107         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
1108                     (data->signal < 0 || data->signal > 100)))
1109                 return NULL;
1110
1111         channel = cfg80211_get_bss_channel(wiphy, ie, ielen, data->chan);
1112         if (!channel)
1113                 return NULL;
1114
1115         memcpy(tmp.pub.bssid, bssid, ETH_ALEN);
1116         tmp.pub.channel = channel;
1117         tmp.pub.scan_width = data->scan_width;
1118         tmp.pub.signal = data->signal;
1119         tmp.pub.beacon_interval = beacon_interval;
1120         tmp.pub.capability = capability;
1121         tmp.ts_boottime = data->boottime_ns;
1122
1123         /*
1124          * If we do not know here whether the IEs are from a Beacon or Probe
1125          * Response frame, we need to pick one of the options and only use it
1126          * with the driver that does not provide the full Beacon/Probe Response
1127          * frame. Use Beacon frame pointer to avoid indicating that this should
1128          * override the IEs pointer should we have received an earlier
1129          * indication of Probe Response data.
1130          */
1131         ies = kzalloc(sizeof(*ies) + ielen, gfp);
1132         if (!ies)
1133                 return NULL;
1134         ies->len = ielen;
1135         ies->tsf = tsf;
1136         ies->from_beacon = false;
1137         memcpy(ies->data, ie, ielen);
1138
1139         switch (ftype) {
1140         case CFG80211_BSS_FTYPE_BEACON:
1141                 ies->from_beacon = true;
1142                 /* fall through to assign */
1143         case CFG80211_BSS_FTYPE_UNKNOWN:
1144                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1145                 break;
1146         case CFG80211_BSS_FTYPE_PRESP:
1147                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1148                 break;
1149         }
1150         rcu_assign_pointer(tmp.pub.ies, ies);
1151
1152         signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
1153                 wiphy->max_adj_channel_rssi_comp;
1154         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1155         if (!res)
1156                 return NULL;
1157
1158         if (channel->band == NL80211_BAND_60GHZ) {
1159                 bss_type = res->pub.capability & WLAN_CAPABILITY_DMG_TYPE_MASK;
1160                 if (bss_type == WLAN_CAPABILITY_DMG_TYPE_AP ||
1161                     bss_type == WLAN_CAPABILITY_DMG_TYPE_PBSS)
1162                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1163         } else {
1164                 if (res->pub.capability & WLAN_CAPABILITY_ESS)
1165                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1166         }
1167
1168         trace_cfg80211_return_bss(&res->pub);
1169         /* cfg80211_bss_update gives us a referenced result */
1170         return &res->pub;
1171 }
1172 EXPORT_SYMBOL(cfg80211_inform_bss_data);
1173
1174 /* cfg80211_inform_bss_width_frame helper */
1175 struct cfg80211_bss *
1176 cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
1177                                struct cfg80211_inform_bss *data,
1178                                struct ieee80211_mgmt *mgmt, size_t len,
1179                                gfp_t gfp)
1180
1181 {
1182         struct cfg80211_internal_bss tmp = {}, *res;
1183         struct cfg80211_bss_ies *ies;
1184         struct ieee80211_channel *channel;
1185         bool signal_valid;
1186         size_t ielen = len - offsetof(struct ieee80211_mgmt,
1187                                       u.probe_resp.variable);
1188         int bss_type;
1189
1190         BUILD_BUG_ON(offsetof(struct ieee80211_mgmt, u.probe_resp.variable) !=
1191                         offsetof(struct ieee80211_mgmt, u.beacon.variable));
1192
1193         trace_cfg80211_inform_bss_frame(wiphy, data, mgmt, len);
1194
1195         if (WARN_ON(!mgmt))
1196                 return NULL;
1197
1198         if (WARN_ON(!wiphy))
1199                 return NULL;
1200
1201         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
1202                     (data->signal < 0 || data->signal > 100)))
1203                 return NULL;
1204
1205         if (WARN_ON(len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
1206                 return NULL;
1207
1208         channel = cfg80211_get_bss_channel(wiphy, mgmt->u.beacon.variable,
1209                                            ielen, data->chan);
1210         if (!channel)
1211                 return NULL;
1212
1213         ies = kzalloc(sizeof(*ies) + ielen, gfp);
1214         if (!ies)
1215                 return NULL;
1216         ies->len = ielen;
1217         ies->tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
1218         ies->from_beacon = ieee80211_is_beacon(mgmt->frame_control);
1219         memcpy(ies->data, mgmt->u.probe_resp.variable, ielen);
1220
1221         if (ieee80211_is_probe_resp(mgmt->frame_control))
1222                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1223         else
1224                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1225         rcu_assign_pointer(tmp.pub.ies, ies);
1226
1227         memcpy(tmp.pub.bssid, mgmt->bssid, ETH_ALEN);
1228         tmp.pub.channel = channel;
1229         tmp.pub.scan_width = data->scan_width;
1230         tmp.pub.signal = data->signal;
1231         tmp.pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
1232         tmp.pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
1233         tmp.ts_boottime = data->boottime_ns;
1234         tmp.parent_tsf = data->parent_tsf;
1235         ether_addr_copy(tmp.parent_bssid, data->parent_bssid);
1236
1237         signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
1238                 wiphy->max_adj_channel_rssi_comp;
1239         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1240         if (!res)
1241                 return NULL;
1242
1243         if (channel->band == NL80211_BAND_60GHZ) {
1244                 bss_type = res->pub.capability & WLAN_CAPABILITY_DMG_TYPE_MASK;
1245                 if (bss_type == WLAN_CAPABILITY_DMG_TYPE_AP ||
1246                     bss_type == WLAN_CAPABILITY_DMG_TYPE_PBSS)
1247                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1248         } else {
1249                 if (res->pub.capability & WLAN_CAPABILITY_ESS)
1250                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1251         }
1252
1253         trace_cfg80211_return_bss(&res->pub);
1254         /* cfg80211_bss_update gives us a referenced result */
1255         return &res->pub;
1256 }
1257 EXPORT_SYMBOL(cfg80211_inform_bss_frame_data);
1258
1259 void cfg80211_ref_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1260 {
1261         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1262         struct cfg80211_internal_bss *bss;
1263
1264         if (!pub)
1265                 return;
1266
1267         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1268
1269         spin_lock_bh(&rdev->bss_lock);
1270         bss_ref_get(rdev, bss);
1271         spin_unlock_bh(&rdev->bss_lock);
1272 }
1273 EXPORT_SYMBOL(cfg80211_ref_bss);
1274
1275 void cfg80211_put_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1276 {
1277         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1278         struct cfg80211_internal_bss *bss;
1279
1280         if (!pub)
1281                 return;
1282
1283         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1284
1285         spin_lock_bh(&rdev->bss_lock);
1286         bss_ref_put(rdev, bss);
1287         spin_unlock_bh(&rdev->bss_lock);
1288 }
1289 EXPORT_SYMBOL(cfg80211_put_bss);
1290
1291 void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1292 {
1293         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1294         struct cfg80211_internal_bss *bss;
1295
1296         if (WARN_ON(!pub))
1297                 return;
1298
1299         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1300
1301         spin_lock_bh(&rdev->bss_lock);
1302         if (!list_empty(&bss->list)) {
1303                 if (__cfg80211_unlink_bss(rdev, bss))
1304                         rdev->bss_generation++;
1305         }
1306         spin_unlock_bh(&rdev->bss_lock);
1307 }
1308 EXPORT_SYMBOL(cfg80211_unlink_bss);
1309
1310 #ifdef CONFIG_CFG80211_WEXT
1311 static struct cfg80211_registered_device *
1312 cfg80211_get_dev_from_ifindex(struct net *net, int ifindex)
1313 {
1314         struct cfg80211_registered_device *rdev;
1315         struct net_device *dev;
1316
1317         ASSERT_RTNL();
1318
1319         dev = dev_get_by_index(net, ifindex);
1320         if (!dev)
1321                 return ERR_PTR(-ENODEV);
1322         if (dev->ieee80211_ptr)
1323                 rdev = wiphy_to_rdev(dev->ieee80211_ptr->wiphy);
1324         else
1325                 rdev = ERR_PTR(-ENODEV);
1326         dev_put(dev);
1327         return rdev;
1328 }
1329
1330 int cfg80211_wext_siwscan(struct net_device *dev,
1331                           struct iw_request_info *info,
1332                           union iwreq_data *wrqu, char *extra)
1333 {
1334         struct cfg80211_registered_device *rdev;
1335         struct wiphy *wiphy;
1336         struct iw_scan_req *wreq = NULL;
1337         struct cfg80211_scan_request *creq = NULL;
1338         int i, err, n_channels = 0;
1339         enum nl80211_band band;
1340
1341         if (!netif_running(dev))
1342                 return -ENETDOWN;
1343
1344         if (wrqu->data.length == sizeof(struct iw_scan_req))
1345                 wreq = (struct iw_scan_req *)extra;
1346
1347         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1348
1349         if (IS_ERR(rdev))
1350                 return PTR_ERR(rdev);
1351
1352         if (rdev->scan_req || rdev->scan_msg) {
1353                 err = -EBUSY;
1354                 goto out;
1355         }
1356
1357         wiphy = &rdev->wiphy;
1358
1359         /* Determine number of channels, needed to allocate creq */
1360         if (wreq && wreq->num_channels)
1361                 n_channels = wreq->num_channels;
1362         else
1363                 n_channels = ieee80211_get_num_supported_channels(wiphy);
1364
1365         creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
1366                        n_channels * sizeof(void *),
1367                        GFP_ATOMIC);
1368         if (!creq) {
1369                 err = -ENOMEM;
1370                 goto out;
1371         }
1372
1373         creq->wiphy = wiphy;
1374         creq->wdev = dev->ieee80211_ptr;
1375         /* SSIDs come after channels */
1376         creq->ssids = (void *)&creq->channels[n_channels];
1377         creq->n_channels = n_channels;
1378         creq->n_ssids = 1;
1379         creq->scan_start = jiffies;
1380
1381         /* translate "Scan on frequencies" request */
1382         i = 0;
1383         for (band = 0; band < NUM_NL80211_BANDS; band++) {
1384                 int j;
1385
1386                 if (!wiphy->bands[band])
1387                         continue;
1388
1389                 for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
1390                         /* ignore disabled channels */
1391                         if (wiphy->bands[band]->channels[j].flags &
1392                                                 IEEE80211_CHAN_DISABLED)
1393                                 continue;
1394
1395                         /* If we have a wireless request structure and the
1396                          * wireless request specifies frequencies, then search
1397                          * for the matching hardware channel.
1398                          */
1399                         if (wreq && wreq->num_channels) {
1400                                 int k;
1401                                 int wiphy_freq = wiphy->bands[band]->channels[j].center_freq;
1402                                 for (k = 0; k < wreq->num_channels; k++) {
1403                                         struct iw_freq *freq =
1404                                                 &wreq->channel_list[k];
1405                                         int wext_freq =
1406                                                 cfg80211_wext_freq(freq);
1407
1408                                         if (wext_freq == wiphy_freq)
1409                                                 goto wext_freq_found;
1410                                 }
1411                                 goto wext_freq_not_found;
1412                         }
1413
1414                 wext_freq_found:
1415                         creq->channels[i] = &wiphy->bands[band]->channels[j];
1416                         i++;
1417                 wext_freq_not_found: ;
1418                 }
1419         }
1420         /* No channels found? */
1421         if (!i) {
1422                 err = -EINVAL;
1423                 goto out;
1424         }
1425
1426         /* Set real number of channels specified in creq->channels[] */
1427         creq->n_channels = i;
1428
1429         /* translate "Scan for SSID" request */
1430         if (wreq) {
1431                 if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
1432                         if (wreq->essid_len > IEEE80211_MAX_SSID_LEN) {
1433                                 err = -EINVAL;
1434                                 goto out;
1435                         }
1436                         memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
1437                         creq->ssids[0].ssid_len = wreq->essid_len;
1438                 }
1439                 if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE)
1440                         creq->n_ssids = 0;
1441         }
1442
1443         for (i = 0; i < NUM_NL80211_BANDS; i++)
1444                 if (wiphy->bands[i])
1445                         creq->rates[i] = (1 << wiphy->bands[i]->n_bitrates) - 1;
1446
1447         eth_broadcast_addr(creq->bssid);
1448
1449         rdev->scan_req = creq;
1450         err = rdev_scan(rdev, creq);
1451         if (err) {
1452                 rdev->scan_req = NULL;
1453                 /* creq will be freed below */
1454         } else {
1455                 nl80211_send_scan_start(rdev, dev->ieee80211_ptr);
1456                 /* creq now owned by driver */
1457                 creq = NULL;
1458                 dev_hold(dev);
1459         }
1460  out:
1461         kfree(creq);
1462         return err;
1463 }
1464 EXPORT_WEXT_HANDLER(cfg80211_wext_siwscan);
1465
1466 static char *ieee80211_scan_add_ies(struct iw_request_info *info,
1467                                     const struct cfg80211_bss_ies *ies,
1468                                     char *current_ev, char *end_buf)
1469 {
1470         const u8 *pos, *end, *next;
1471         struct iw_event iwe;
1472
1473         if (!ies)
1474                 return current_ev;
1475
1476         /*
1477          * If needed, fragment the IEs buffer (at IE boundaries) into short
1478          * enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
1479          */
1480         pos = ies->data;
1481         end = pos + ies->len;
1482
1483         while (end - pos > IW_GENERIC_IE_MAX) {
1484                 next = pos + 2 + pos[1];
1485                 while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
1486                         next = next + 2 + next[1];
1487
1488                 memset(&iwe, 0, sizeof(iwe));
1489                 iwe.cmd = IWEVGENIE;
1490                 iwe.u.data.length = next - pos;
1491                 current_ev = iwe_stream_add_point_check(info, current_ev,
1492                                                         end_buf, &iwe,
1493                                                         (void *)pos);
1494                 if (IS_ERR(current_ev))
1495                         return current_ev;
1496                 pos = next;
1497         }
1498
1499         if (end > pos) {
1500                 memset(&iwe, 0, sizeof(iwe));
1501                 iwe.cmd = IWEVGENIE;
1502                 iwe.u.data.length = end - pos;
1503                 current_ev = iwe_stream_add_point_check(info, current_ev,
1504                                                         end_buf, &iwe,
1505                                                         (void *)pos);
1506                 if (IS_ERR(current_ev))
1507                         return current_ev;
1508         }
1509
1510         return current_ev;
1511 }
1512
1513 static char *
1514 ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,
1515               struct cfg80211_internal_bss *bss, char *current_ev,
1516               char *end_buf)
1517 {
1518         const struct cfg80211_bss_ies *ies;
1519         struct iw_event iwe;
1520         const u8 *ie;
1521         u8 buf[50];
1522         u8 *cfg, *p, *tmp;
1523         int rem, i, sig;
1524         bool ismesh = false;
1525
1526         memset(&iwe, 0, sizeof(iwe));
1527         iwe.cmd = SIOCGIWAP;
1528         iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
1529         memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN);
1530         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1531                                                 IW_EV_ADDR_LEN);
1532         if (IS_ERR(current_ev))
1533                 return current_ev;
1534
1535         memset(&iwe, 0, sizeof(iwe));
1536         iwe.cmd = SIOCGIWFREQ;
1537         iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq);
1538         iwe.u.freq.e = 0;
1539         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1540                                                 IW_EV_FREQ_LEN);
1541         if (IS_ERR(current_ev))
1542                 return current_ev;
1543
1544         memset(&iwe, 0, sizeof(iwe));
1545         iwe.cmd = SIOCGIWFREQ;
1546         iwe.u.freq.m = bss->pub.channel->center_freq;
1547         iwe.u.freq.e = 6;
1548         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1549                                                 IW_EV_FREQ_LEN);
1550         if (IS_ERR(current_ev))
1551                 return current_ev;
1552
1553         if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) {
1554                 memset(&iwe, 0, sizeof(iwe));
1555                 iwe.cmd = IWEVQUAL;
1556                 iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED |
1557                                      IW_QUAL_NOISE_INVALID |
1558                                      IW_QUAL_QUAL_UPDATED;
1559                 switch (wiphy->signal_type) {
1560                 case CFG80211_SIGNAL_TYPE_MBM:
1561                         sig = bss->pub.signal / 100;
1562                         iwe.u.qual.level = sig;
1563                         iwe.u.qual.updated |= IW_QUAL_DBM;
1564                         if (sig < -110)         /* rather bad */
1565                                 sig = -110;
1566                         else if (sig > -40)     /* perfect */
1567                                 sig = -40;
1568                         /* will give a range of 0 .. 70 */
1569                         iwe.u.qual.qual = sig + 110;
1570                         break;
1571                 case CFG80211_SIGNAL_TYPE_UNSPEC:
1572                         iwe.u.qual.level = bss->pub.signal;
1573                         /* will give range 0 .. 100 */
1574                         iwe.u.qual.qual = bss->pub.signal;
1575                         break;
1576                 default:
1577                         /* not reached */
1578                         break;
1579                 }
1580                 current_ev = iwe_stream_add_event_check(info, current_ev,
1581                                                         end_buf, &iwe,
1582                                                         IW_EV_QUAL_LEN);
1583                 if (IS_ERR(current_ev))
1584                         return current_ev;
1585         }
1586
1587         memset(&iwe, 0, sizeof(iwe));
1588         iwe.cmd = SIOCGIWENCODE;
1589         if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY)
1590                 iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
1591         else
1592                 iwe.u.data.flags = IW_ENCODE_DISABLED;
1593         iwe.u.data.length = 0;
1594         current_ev = iwe_stream_add_point_check(info, current_ev, end_buf,
1595                                                 &iwe, "");
1596         if (IS_ERR(current_ev))
1597                 return current_ev;
1598
1599         rcu_read_lock();
1600         ies = rcu_dereference(bss->pub.ies);
1601         rem = ies->len;
1602         ie = ies->data;
1603
1604         while (rem >= 2) {
1605                 /* invalid data */
1606                 if (ie[1] > rem - 2)
1607                         break;
1608
1609                 switch (ie[0]) {
1610                 case WLAN_EID_SSID:
1611                         memset(&iwe, 0, sizeof(iwe));
1612                         iwe.cmd = SIOCGIWESSID;
1613                         iwe.u.data.length = ie[1];
1614                         iwe.u.data.flags = 1;
1615                         current_ev = iwe_stream_add_point_check(info,
1616                                                                 current_ev,
1617                                                                 end_buf, &iwe,
1618                                                                 (u8 *)ie + 2);
1619                         if (IS_ERR(current_ev))
1620                                 goto unlock;
1621                         break;
1622                 case WLAN_EID_MESH_ID:
1623                         memset(&iwe, 0, sizeof(iwe));
1624                         iwe.cmd = SIOCGIWESSID;
1625                         iwe.u.data.length = ie[1];
1626                         iwe.u.data.flags = 1;
1627                         current_ev = iwe_stream_add_point_check(info,
1628                                                                 current_ev,
1629                                                                 end_buf, &iwe,
1630                                                                 (u8 *)ie + 2);
1631                         if (IS_ERR(current_ev))
1632                                 goto unlock;
1633                         break;
1634                 case WLAN_EID_MESH_CONFIG:
1635                         ismesh = true;
1636                         if (ie[1] != sizeof(struct ieee80211_meshconf_ie))
1637                                 break;
1638                         cfg = (u8 *)ie + 2;
1639                         memset(&iwe, 0, sizeof(iwe));
1640                         iwe.cmd = IWEVCUSTOM;
1641                         sprintf(buf, "Mesh Network Path Selection Protocol ID: "
1642                                 "0x%02X", cfg[0]);
1643                         iwe.u.data.length = strlen(buf);
1644                         current_ev = iwe_stream_add_point_check(info,
1645                                                                 current_ev,
1646                                                                 end_buf,
1647                                                                 &iwe, buf);
1648                         if (IS_ERR(current_ev))
1649                                 goto unlock;
1650                         sprintf(buf, "Path Selection Metric ID: 0x%02X",
1651                                 cfg[1]);
1652                         iwe.u.data.length = strlen(buf);
1653                         current_ev = iwe_stream_add_point_check(info,
1654                                                                 current_ev,
1655                                                                 end_buf,
1656                                                                 &iwe, buf);
1657                         if (IS_ERR(current_ev))
1658                                 goto unlock;
1659                         sprintf(buf, "Congestion Control Mode ID: 0x%02X",
1660                                 cfg[2]);
1661                         iwe.u.data.length = strlen(buf);
1662                         current_ev = iwe_stream_add_point_check(info,
1663                                                                 current_ev,
1664                                                                 end_buf,
1665                                                                 &iwe, buf);
1666                         if (IS_ERR(current_ev))
1667                                 goto unlock;
1668                         sprintf(buf, "Synchronization ID: 0x%02X", cfg[3]);
1669                         iwe.u.data.length = strlen(buf);
1670                         current_ev = iwe_stream_add_point_check(info,
1671                                                                 current_ev,
1672                                                                 end_buf,
1673                                                                 &iwe, buf);
1674                         if (IS_ERR(current_ev))
1675                                 goto unlock;
1676                         sprintf(buf, "Authentication ID: 0x%02X", cfg[4]);
1677                         iwe.u.data.length = strlen(buf);
1678                         current_ev = iwe_stream_add_point_check(info,
1679                                                                 current_ev,
1680                                                                 end_buf,
1681                                                                 &iwe, buf);
1682                         if (IS_ERR(current_ev))
1683                                 goto unlock;
1684                         sprintf(buf, "Formation Info: 0x%02X", cfg[5]);
1685                         iwe.u.data.length = strlen(buf);
1686                         current_ev = iwe_stream_add_point_check(info,
1687                                                                 current_ev,
1688                                                                 end_buf,
1689                                                                 &iwe, buf);
1690                         if (IS_ERR(current_ev))
1691                                 goto unlock;
1692                         sprintf(buf, "Capabilities: 0x%02X", cfg[6]);
1693                         iwe.u.data.length = strlen(buf);
1694                         current_ev = iwe_stream_add_point_check(info,
1695                                                                 current_ev,
1696                                                                 end_buf,
1697                                                                 &iwe, buf);
1698                         if (IS_ERR(current_ev))
1699                                 goto unlock;
1700                         break;
1701                 case WLAN_EID_SUPP_RATES:
1702                 case WLAN_EID_EXT_SUPP_RATES:
1703                         /* display all supported rates in readable format */
1704                         p = current_ev + iwe_stream_lcp_len(info);
1705
1706                         memset(&iwe, 0, sizeof(iwe));
1707                         iwe.cmd = SIOCGIWRATE;
1708                         /* Those two flags are ignored... */
1709                         iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;
1710
1711                         for (i = 0; i < ie[1]; i++) {
1712                                 iwe.u.bitrate.value =
1713                                         ((ie[i + 2] & 0x7f) * 500000);
1714                                 tmp = p;
1715                                 p = iwe_stream_add_value(info, current_ev, p,
1716                                                          end_buf, &iwe,
1717                                                          IW_EV_PARAM_LEN);
1718                                 if (p == tmp) {
1719                                         current_ev = ERR_PTR(-E2BIG);
1720                                         goto unlock;
1721                                 }
1722                         }
1723                         current_ev = p;
1724                         break;
1725                 }
1726                 rem -= ie[1] + 2;
1727                 ie += ie[1] + 2;
1728         }
1729
1730         if (bss->pub.capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS) ||
1731             ismesh) {
1732                 memset(&iwe, 0, sizeof(iwe));
1733                 iwe.cmd = SIOCGIWMODE;
1734                 if (ismesh)
1735                         iwe.u.mode = IW_MODE_MESH;
1736                 else if (bss->pub.capability & WLAN_CAPABILITY_ESS)
1737                         iwe.u.mode = IW_MODE_MASTER;
1738                 else
1739                         iwe.u.mode = IW_MODE_ADHOC;
1740                 current_ev = iwe_stream_add_event_check(info, current_ev,
1741                                                         end_buf, &iwe,
1742                                                         IW_EV_UINT_LEN);
1743                 if (IS_ERR(current_ev))
1744                         goto unlock;
1745         }
1746
1747         memset(&iwe, 0, sizeof(iwe));
1748         iwe.cmd = IWEVCUSTOM;
1749         sprintf(buf, "tsf=%016llx", (unsigned long long)(ies->tsf));
1750         iwe.u.data.length = strlen(buf);
1751         current_ev = iwe_stream_add_point_check(info, current_ev, end_buf,
1752                                                 &iwe, buf);
1753         if (IS_ERR(current_ev))
1754                 goto unlock;
1755         memset(&iwe, 0, sizeof(iwe));
1756         iwe.cmd = IWEVCUSTOM;
1757         sprintf(buf, " Last beacon: %ums ago",
1758                 elapsed_jiffies_msecs(bss->ts));
1759         iwe.u.data.length = strlen(buf);
1760         current_ev = iwe_stream_add_point_check(info, current_ev,
1761                                                 end_buf, &iwe, buf);
1762         if (IS_ERR(current_ev))
1763                 goto unlock;
1764
1765         current_ev = ieee80211_scan_add_ies(info, ies, current_ev, end_buf);
1766
1767  unlock:
1768         rcu_read_unlock();
1769         return current_ev;
1770 }
1771
1772
1773 static int ieee80211_scan_results(struct cfg80211_registered_device *rdev,
1774                                   struct iw_request_info *info,
1775                                   char *buf, size_t len)
1776 {
1777         char *current_ev = buf;
1778         char *end_buf = buf + len;
1779         struct cfg80211_internal_bss *bss;
1780         int err = 0;
1781
1782         spin_lock_bh(&rdev->bss_lock);
1783         cfg80211_bss_expire(rdev);
1784
1785         list_for_each_entry(bss, &rdev->bss_list, list) {
1786                 if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
1787                         err = -E2BIG;
1788                         break;
1789                 }
1790                 current_ev = ieee80211_bss(&rdev->wiphy, info, bss,
1791                                            current_ev, end_buf);
1792                 if (IS_ERR(current_ev)) {
1793                         err = PTR_ERR(current_ev);
1794                         break;
1795                 }
1796         }
1797         spin_unlock_bh(&rdev->bss_lock);
1798
1799         if (err)
1800                 return err;
1801         return current_ev - buf;
1802 }
1803
1804
1805 int cfg80211_wext_giwscan(struct net_device *dev,
1806                           struct iw_request_info *info,
1807                           struct iw_point *data, char *extra)
1808 {
1809         struct cfg80211_registered_device *rdev;
1810         int res;
1811
1812         if (!netif_running(dev))
1813                 return -ENETDOWN;
1814
1815         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1816
1817         if (IS_ERR(rdev))
1818                 return PTR_ERR(rdev);
1819
1820         if (rdev->scan_req || rdev->scan_msg)
1821                 return -EAGAIN;
1822
1823         res = ieee80211_scan_results(rdev, info, extra, data->length);
1824         data->length = 0;
1825         if (res >= 0) {
1826                 data->length = res;
1827                 res = 0;
1828         }
1829
1830         return res;
1831 }
1832 EXPORT_WEXT_HANDLER(cfg80211_wext_giwscan);
1833 #endif