net/wireless/scan.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * cfg80211 scan result handling
   4  *
   5  * Copyright 2008 Johannes Berg <johannes@sipsolutions.net>
   6  * Copyright 2013-2014  Intel Mobile Communications GmbH
   7  * Copyright 2016       Intel Deutschland GmbH
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/slab.h>
  11 #include <linux/module.h>
  12 #include <linux/netdevice.h>
  13 #include <linux/wireless.h>
  14 #include <linux/nl80211.h>
  15 #include <linux/etherdevice.h>
  16 #include <net/arp.h>
  17 #include <net/cfg80211.h>
  18 #include <net/cfg80211-wext.h>
  19 #include <net/iw_handler.h>
  20 #include "core.h"
  21 #include "nl80211.h"
  22 #include "wext-compat.h"
  23 #include "rdev-ops.h"
  24
  25 /**
  26  * DOC: BSS tree/list structure
  27  *
  28  * At the top level, the BSS list is kept in both a list in each
  29  * registered device (@bss_list) as well as an RB-tree for faster
  30  * lookup. In the RB-tree, entries can be looked up using their
  31  * channel, MESHID, MESHCONF (for MBSSes) or channel, BSSID, SSID
  32  * for other BSSes.
  33  *
  34  * Due to the possibility of hidden SSIDs, there's a second level
  35  * structure, the "hidden_list" and "hidden_beacon_bss" pointer.
  36  * The hidden_list connects all BSSes belonging to a single AP
  37  * that has a hidden SSID, and connects beacon and probe response
  38  * entries. For a probe response entry for a hidden SSID, the
  39  * hidden_beacon_bss pointer points to the BSS struct holding the
  40  * beacon's information.
  41  *
  42  * Reference counting is done for all these references except for
  43  * the hidden_list, so that a beacon BSS struct that is otherwise
  44  * not referenced has one reference for being on the bss_list and
  45  * one for each probe response entry that points to it using the
  46  * hidden_beacon_bss pointer. When a BSS struct that has such a
  47  * pointer is get/put, the refcount update is also propagated to
  48  * the referenced struct, this ensure that it cannot get removed
  49  * while somebody is using the probe response version.
  50  *
  51  * Note that the hidden_beacon_bss pointer never changes, due to
  52  * the reference counting. Therefore, no locking is needed for
  53  * it.
  54  *
  55  * Also note that the hidden_beacon_bss pointer is only relevant
  56  * if the driver uses something other than the IEs, e.g. private
  57  * data stored stored in the BSS struct, since the beacon IEs are
  58  * also linked into the probe response struct.
  59  */
  60
  61 /*
  62  * Limit the number of BSS entries stored in mac80211. Each one is
  63  * a bit over 4k at most, so this limits to roughly 4-5M of memory.
  64  * If somebody wants to really attack this though, they'd likely
  65  * use small beacons, and only one type of frame, limiting each of
  66  * the entries to a much smaller size (in order to generate more
  67  * entries in total, so overhead is bigger.)
  68  */
  69 static int bss_entries_limit = 1000;
  70 module_param(bss_entries_limit, int, 0644);
  71 MODULE_PARM_DESC(bss_entries_limit,
  72                  "limit to number of scan BSS entries (per wiphy, default 1000)");
  73
  74 #define IEEE80211_SCAN_RESULT_EXPIRE    (30 * HZ)
  75
  76 static void bss_free(struct cfg80211_internal_bss *bss)
  77 {
  78         struct cfg80211_bss_ies *ies;
  79
  80         if (WARN_ON(atomic_read(&bss->hold)))
  81                 return;
  82
  83         ies = (void *)rcu_access_pointer(bss->pub.beacon_ies);
  84         if (ies && !bss->pub.hidden_beacon_bss)
  85                 kfree_rcu(ies, rcu_head);
  86         ies = (void *)rcu_access_pointer(bss->pub.proberesp_ies);
  87         if (ies)
  88                 kfree_rcu(ies, rcu_head);
  89
  90         /*
  91          * This happens when the module is removed, it doesn't
  92          * really matter any more save for completeness
  93          */
  94         if (!list_empty(&bss->hidden_list))
  95                 list_del(&bss->hidden_list);
  96
  97         kfree(bss);
  98 }
  99
 100 static inline void bss_ref_get(struct cfg80211_registered_device *rdev,
 101                                struct cfg80211_internal_bss *bss)
 102 {
 103         lockdep_assert_held(&rdev->bss_lock);
 104
 105         bss->refcount++;
 106         if (bss->pub.hidden_beacon_bss) {
 107                 bss = container_of(bss->pub.hidden_beacon_bss,
 108                                    struct cfg80211_internal_bss,
 109                                    pub);
 110                 bss->refcount++;
 111         }
 112 }
 113
 114 static inline void bss_ref_put(struct cfg80211_registered_device *rdev,
 115                                struct cfg80211_internal_bss *bss)
 116 {
 117         lockdep_assert_held(&rdev->bss_lock);
 118
 119         if (bss->pub.hidden_beacon_bss) {
 120                 struct cfg80211_internal_bss *hbss;
 121                 hbss = container_of(bss->pub.hidden_beacon_bss,
 122                                     struct cfg80211_internal_bss,
 123                                     pub);
 124                 hbss->refcount--;
 125                 if (hbss->refcount == 0)
 126                         bss_free(hbss);
 127         }
 128         bss->refcount--;
 129         if (bss->refcount == 0)
 130                 bss_free(bss);
 131 }
 132
 133 static bool __cfg80211_unlink_bss(struct cfg80211_registered_device *rdev,
 134                                   struct cfg80211_internal_bss *bss)
 135 {
 136         lockdep_assert_held(&rdev->bss_lock);
 137
 138         if (!list_empty(&bss->hidden_list)) {
 139                 /*
 140                  * don't remove the beacon entry if it has
 141                  * probe responses associated with it
 142                  */
 143                 if (!bss->pub.hidden_beacon_bss)
 144                         return false;
 145                 /*
 146                  * if it's a probe response entry break its
 147                  * link to the other entries in the group
 148                  */
 149                 list_del_init(&bss->hidden_list);
 150         }
 151
 152         list_del_init(&bss->list);
 153         rb_erase(&bss->rbn, &rdev->bss_tree);
 154         rdev->bss_entries--;
 155         WARN_ONCE((rdev->bss_entries == 0) ^ list_empty(&rdev->bss_list),
 156                   "rdev bss entries[%d]/list[empty:%d] corruption\n",
 157                   rdev->bss_entries, list_empty(&rdev->bss_list));
 158         bss_ref_put(rdev, bss);
 159         return true;
 160 }
 161
 162 static void __cfg80211_bss_expire(struct cfg80211_registered_device *rdev,
 163                                   unsigned long expire_time)
 164 {
 165         struct cfg80211_internal_bss *bss, *tmp;
 166         bool expired = false;
 167
 168         lockdep_assert_held(&rdev->bss_lock);
 169
 170         list_for_each_entry_safe(bss, tmp, &rdev->bss_list, list) {
 171                 if (atomic_read(&bss->hold))
 172                         continue;
 173                 if (!time_after(expire_time, bss->ts))
 174                         continue;
 175
 176                 if (__cfg80211_unlink_bss(rdev, bss))
 177                         expired = true;
 178         }
 179
 180         if (expired)
 181                 rdev->bss_generation++;
 182 }
 183
 184 static bool cfg80211_bss_expire_oldest(struct cfg80211_registered_device *rdev)
 185 {
 186         struct cfg80211_internal_bss *bss, *oldest = NULL;
 187         bool ret;
 188
 189         lockdep_assert_held(&rdev->bss_lock);
 190
 191         list_for_each_entry(bss, &rdev->bss_list, list) {
 192                 if (atomic_read(&bss->hold))
 193                         continue;
 194
 195                 if (!list_empty(&bss->hidden_list) &&
 196                     !bss->pub.hidden_beacon_bss)
 197                         continue;
 198
 199                 if (oldest && time_before(oldest->ts, bss->ts))
 200                         continue;
 201                 oldest = bss;
 202         }
 203
 204         if (WARN_ON(!oldest))
 205                 return false;
 206
 207         /*
 208          * The callers make sure to increase rdev->bss_generation if anything
 209          * gets removed (and a new entry added), so there's no need to also do
 210          * it here.
 211          */
 212
 213         ret = __cfg80211_unlink_bss(rdev, oldest);
 214         WARN_ON(!ret);
 215         return ret;
 216 }
 217
 218 void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev,
 219                            bool send_message)
 220 {
 221         struct cfg80211_scan_request *request;
 222         struct wireless_dev *wdev;
 223         struct sk_buff *msg;
 224 #ifdef CONFIG_CFG80211_WEXT
 225         union iwreq_data wrqu;
 226 #endif
 227
 228         ASSERT_RTNL();
 229
 230         if (rdev->scan_msg) {
 231                 nl80211_send_scan_msg(rdev, rdev->scan_msg);
 232                 rdev->scan_msg = NULL;
 233                 return;
 234         }
 235
 236         request = rdev->scan_req;
 237         if (!request)
 238                 return;
 239
 240         wdev = request->wdev;
 241
 242         /*
 243          * This must be before sending the other events!
 244          * Otherwise, wpa_supplicant gets completely confused with
 245          * wext events.
 246          */
 247         if (wdev->netdev)
 248                 cfg80211_sme_scan_done(wdev->netdev);
 249
 250         if (!request->info.aborted &&
 251             request->flags & NL80211_SCAN_FLAG_FLUSH) {
 252                 /* flush entries from previous scans */
 253                 spin_lock_bh(&rdev->bss_lock);
 254                 __cfg80211_bss_expire(rdev, request->scan_start);
 255                 spin_unlock_bh(&rdev->bss_lock);
 256         }
 257
 258         msg = nl80211_build_scan_msg(rdev, wdev, request->info.aborted);
 259
 260 #ifdef CONFIG_CFG80211_WEXT
 261         if (wdev->netdev && !request->info.aborted) {
 262                 memset(&wrqu, 0, sizeof(wrqu));
 263
 264                 wireless_send_event(wdev->netdev, SIOCGIWSCAN, &wrqu, NULL);
 265         }
 266 #endif
 267
 268         if (wdev->netdev)
 269                 dev_put(wdev->netdev);
 270
 271         rdev->scan_req = NULL;
 272         kfree(request);
 273
 274         if (!send_message)
 275                 rdev->scan_msg = msg;
 276         else
 277                 nl80211_send_scan_msg(rdev, msg);
 278 }
 279
 280 void __cfg80211_scan_done(struct work_struct *wk)
 281 {
 282         struct cfg80211_registered_device *rdev;
 283
 284         rdev = container_of(wk, struct cfg80211_registered_device,
 285                             scan_done_wk);
 286
 287         rtnl_lock();
 288         ___cfg80211_scan_done(rdev, true);
 289         rtnl_unlock();
 290 }
 291
 292 void cfg80211_scan_done(struct cfg80211_scan_request *request,
 293                         struct cfg80211_scan_info *info)
 294 {
 295         trace_cfg80211_scan_done(request, info);
 296         WARN_ON(request != wiphy_to_rdev(request->wiphy)->scan_req);
 297
 298         request->info = *info;
 299         request->notified = true;
 300         queue_work(cfg80211_wq, &wiphy_to_rdev(request->wiphy)->scan_done_wk);
 301 }
 302 EXPORT_SYMBOL(cfg80211_scan_done);
 303
 304 void cfg80211_add_sched_scan_req(struct cfg80211_registered_device *rdev,
 305                                  struct cfg80211_sched_scan_request *req)
 306 {
 307         ASSERT_RTNL();
 308
 309         list_add_rcu(&req->list, &rdev->sched_scan_req_list);
 310 }
 311
 312 static void cfg80211_del_sched_scan_req(struct cfg80211_registered_device *rdev,
 313                                         struct cfg80211_sched_scan_request *req)
 314 {
 315         ASSERT_RTNL();
 316
 317         list_del_rcu(&req->list);
 318         kfree_rcu(req, rcu_head);
 319 }
 320
 321 static struct cfg80211_sched_scan_request *
 322 cfg80211_find_sched_scan_req(struct cfg80211_registered_device *rdev, u64 reqid)
 323 {
 324         struct cfg80211_sched_scan_request *pos;
 325
 326         WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_rtnl_is_held());
 327
 328         list_for_each_entry_rcu(pos, &rdev->sched_scan_req_list, list) {
 329                 if (pos->reqid == reqid)
 330                         return pos;
 331         }
 332         return NULL;
 333 }
 334
 335 /*
 336  * Determines if a scheduled scan request can be handled. When a legacy
 337  * scheduled scan is running no other scheduled scan is allowed regardless
 338  * whether the request is for legacy or multi-support scan. When a multi-support
 339  * scheduled scan is running a request for legacy scan is not allowed. In this
 340  * case a request for multi-support scan can be handled if resources are
 341  * available, ie. struct wiphy::max_sched_scan_reqs limit is not yet reached.
 342  */
 343 int cfg80211_sched_scan_req_possible(struct cfg80211_registered_device *rdev,
 344                                      bool want_multi)
 345 {
 346         struct cfg80211_sched_scan_request *pos;
 347         int i = 0;
 348
 349         list_for_each_entry(pos, &rdev->sched_scan_req_list, list) {
 350                 /* request id zero means legacy in progress */
 351                 if (!i && !pos->reqid)
 352                         return -EINPROGRESS;
 353                 i++;
 354         }
 355
 356         if (i) {
 357                 /* no legacy allowed when multi request(s) are active */
 358                 if (!want_multi)
 359                         return -EINPROGRESS;
 360
 361                 /* resource limit reached */
 362                 if (i == rdev->wiphy.max_sched_scan_reqs)
 363                         return -ENOSPC;
 364         }
 365         return 0;
 366 }
 367
 368 void cfg80211_sched_scan_results_wk(struct work_struct *work)
 369 {
 370         struct cfg80211_registered_device *rdev;
 371         struct cfg80211_sched_scan_request *req, *tmp;
 372
 373         rdev = container_of(work, struct cfg80211_registered_device,
 374                            sched_scan_res_wk);
 375
 376         rtnl_lock();
 377         list_for_each_entry_safe(req, tmp, &rdev->sched_scan_req_list, list) {
 378                 if (req->report_results) {
 379                         req->report_results = false;
 380                         if (req->flags & NL80211_SCAN_FLAG_FLUSH) {
 381                                 /* flush entries from previous scans */
 382                                 spin_lock_bh(&rdev->bss_lock);
 383                                 __cfg80211_bss_expire(rdev, req->scan_start);
 384                                 spin_unlock_bh(&rdev->bss_lock);
 385                                 req->scan_start = jiffies;
 386                         }
 387                         nl80211_send_sched_scan(req,
 388                                                 NL80211_CMD_SCHED_SCAN_RESULTS);
 389                 }
 390         }
 391         rtnl_unlock();
 392 }
 393
 394 void cfg80211_sched_scan_results(struct wiphy *wiphy, u64 reqid)
 395 {
 396         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 397         struct cfg80211_sched_scan_request *request;
 398
 399         trace_cfg80211_sched_scan_results(wiphy, reqid);
 400         /* ignore if we're not scanning */
 401
 402         rcu_read_lock();
 403         request = cfg80211_find_sched_scan_req(rdev, reqid);
 404         if (request) {
 405                 request->report_results = true;
 406                 queue_work(cfg80211_wq, &rdev->sched_scan_res_wk);
 407         }
 408         rcu_read_unlock();
 409 }
 410 EXPORT_SYMBOL(cfg80211_sched_scan_results);
 411
 412 void cfg80211_sched_scan_stopped_rtnl(struct wiphy *wiphy, u64 reqid)
 413 {
 414         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 415
 416         ASSERT_RTNL();
 417
 418         trace_cfg80211_sched_scan_stopped(wiphy, reqid);
 419
 420         __cfg80211_stop_sched_scan(rdev, reqid, true);
 421 }
 422 EXPORT_SYMBOL(cfg80211_sched_scan_stopped_rtnl);
 423
 424 void cfg80211_sched_scan_stopped(struct wiphy *wiphy, u64 reqid)
 425 {
 426         rtnl_lock();
 427         cfg80211_sched_scan_stopped_rtnl(wiphy, reqid);
 428         rtnl_unlock();
 429 }
 430 EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
 431
 432 int cfg80211_stop_sched_scan_req(struct cfg80211_registered_device *rdev,
 433                                  struct cfg80211_sched_scan_request *req,
 434                                  bool driver_initiated)
 435 {
 436         ASSERT_RTNL();
 437
 438         if (!driver_initiated) {
 439                 int err = rdev_sched_scan_stop(rdev, req->dev, req->reqid);
 440                 if (err)
 441                         return err;
 442         }
 443
 444         nl80211_send_sched_scan(req, NL80211_CMD_SCHED_SCAN_STOPPED);
 445
 446         cfg80211_del_sched_scan_req(rdev, req);
 447
 448         return 0;
 449 }
 450
 451 int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
 452                                u64 reqid, bool driver_initiated)
 453 {
 454         struct cfg80211_sched_scan_request *sched_scan_req;
 455
 456         ASSERT_RTNL();
 457
 458         sched_scan_req = cfg80211_find_sched_scan_req(rdev, reqid);
 459         if (!sched_scan_req)
 460                 return -ENOENT;
 461
 462         return cfg80211_stop_sched_scan_req(rdev, sched_scan_req,
 463                                             driver_initiated);
 464 }
 465
 466 void cfg80211_bss_age(struct cfg80211_registered_device *rdev,
 467                       unsigned long age_secs)
 468 {
 469         struct cfg80211_internal_bss *bss;
 470         unsigned long age_jiffies = msecs_to_jiffies(age_secs * MSEC_PER_SEC);
 471
 472         spin_lock_bh(&rdev->bss_lock);
 473         list_for_each_entry(bss, &rdev->bss_list, list)
 474                 bss->ts -= age_jiffies;
 475         spin_unlock_bh(&rdev->bss_lock);
 476 }
 477
 478 void cfg80211_bss_expire(struct cfg80211_registered_device *rdev)
 479 {
 480         __cfg80211_bss_expire(rdev, jiffies - IEEE80211_SCAN_RESULT_EXPIRE);
 481 }
 482
 483 const u8 *cfg80211_find_ie_match(u8 eid, const u8 *ies, int len,
 484                                  const u8 *match, int match_len,
 485                                  int match_offset)
 486 {
 487         const struct element *elem;
 488
 489         /* match_offset can't be smaller than 2, unless match_len is
 490          * zero, in which case match_offset must be zero as well.
 491          */
 492         if (WARN_ON((match_len && match_offset < 2) ||
 493                     (!match_len && match_offset)))
 494                 return NULL;
 495
 496         for_each_element_id(elem, eid, ies, len) {
 497                 if (elem->datalen >= match_offset - 2 + match_len &&
 498                     !memcmp(elem->data + match_offset - 2, match, match_len))
 499                         return (void *)elem;
 500         }
 501
 502         return NULL;
 503 }
 504 EXPORT_SYMBOL(cfg80211_find_ie_match);
 505
 506 const u8 *cfg80211_find_vendor_ie(unsigned int oui, int oui_type,
 507                                   const u8 *ies, int len)
 508 {
 509         const u8 *ie;
 510         u8 match[] = { oui >> 16, oui >> 8, oui, oui_type };
 511         int match_len = (oui_type < 0) ? 3 : sizeof(match);
 512
 513         if (WARN_ON(oui_type > 0xff))
 514                 return NULL;
 515
 516         ie = cfg80211_find_ie_match(WLAN_EID_VENDOR_SPECIFIC, ies, len,
 517                                     match, match_len, 2);
 518
 519         if (ie && (ie[1] < 4))
 520                 return NULL;
 521
 522         return ie;
 523 }
 524 EXPORT_SYMBOL(cfg80211_find_vendor_ie);
 525
 526 static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
 527                    const u8 *ssid, size_t ssid_len)
 528 {
 529         const struct cfg80211_bss_ies *ies;
 530         const u8 *ssidie;
 531
 532         if (bssid && !ether_addr_equal(a->bssid, bssid))
 533                 return false;
 534
 535         if (!ssid)
 536                 return true;
 537
 538         ies = rcu_access_pointer(a->ies);
 539         if (!ies)
 540                 return false;
 541         ssidie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 542         if (!ssidie)
 543                 return false;
 544         if (ssidie[1] != ssid_len)
 545                 return false;
 546         return memcmp(ssidie + 2, ssid, ssid_len) == 0;
 547 }
 548
 549 /**
 550  * enum bss_compare_mode - BSS compare mode
 551  * @BSS_CMP_REGULAR: regular compare mode (for insertion and normal find)
 552  * @BSS_CMP_HIDE_ZLEN: find hidden SSID with zero-length mode
 553  * @BSS_CMP_HIDE_NUL: find hidden SSID with NUL-ed out mode
 554  */
 555 enum bss_compare_mode {
 556         BSS_CMP_REGULAR,
 557         BSS_CMP_HIDE_ZLEN,
 558         BSS_CMP_HIDE_NUL,
 559 };
 560
 561 static int cmp_bss(struct cfg80211_bss *a,
 562                    struct cfg80211_bss *b,
 563                    enum bss_compare_mode mode)
 564 {
 565         const struct cfg80211_bss_ies *a_ies, *b_ies;
 566         const u8 *ie1 = NULL;
 567         const u8 *ie2 = NULL;
 568         int i, r;
 569
 570         if (a->channel != b->channel)
 571                 return b->channel->center_freq - a->channel->center_freq;
 572
 573         a_ies = rcu_access_pointer(a->ies);
 574         if (!a_ies)
 575                 return -1;
 576         b_ies = rcu_access_pointer(b->ies);
 577         if (!b_ies)
 578                 return 1;
 579
 580         if (WLAN_CAPABILITY_IS_STA_BSS(a->capability))
 581                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 582                                        a_ies->data, a_ies->len);
 583         if (WLAN_CAPABILITY_IS_STA_BSS(b->capability))
 584                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 585                                        b_ies->data, b_ies->len);
 586         if (ie1 && ie2) {
 587                 int mesh_id_cmp;
 588
 589                 if (ie1[1] == ie2[1])
 590                         mesh_id_cmp = memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 591                 else
 592                         mesh_id_cmp = ie2[1] - ie1[1];
 593
 594                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 595                                        a_ies->data, a_ies->len);
 596                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 597                                        b_ies->data, b_ies->len);
 598                 if (ie1 && ie2) {
 599                         if (mesh_id_cmp)
 600                                 return mesh_id_cmp;
 601                         if (ie1[1] != ie2[1])
 602                                 return ie2[1] - ie1[1];
 603                         return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 604                 }
 605         }
 606
 607         r = memcmp(a->bssid, b->bssid, sizeof(a->bssid));
 608         if (r)
 609                 return r;
 610
 611         ie1 = cfg80211_find_ie(WLAN_EID_SSID, a_ies->data, a_ies->len);
 612         ie2 = cfg80211_find_ie(WLAN_EID_SSID, b_ies->data, b_ies->len);
 613
 614         if (!ie1 && !ie2)
 615                 return 0;
 616
 617         /*
 618          * Note that with "hide_ssid", the function returns a match if
 619          * the already-present BSS ("b") is a hidden SSID beacon for
 620          * the new BSS ("a").
 621          */
 622
 623         /* sort missing IE before (left of) present IE */
 624         if (!ie1)
 625                 return -1;
 626         if (!ie2)
 627                 return 1;
 628
 629         switch (mode) {
 630         case BSS_CMP_HIDE_ZLEN:
 631                 /*
 632                  * In ZLEN mode we assume the BSS entry we're
 633                  * looking for has a zero-length SSID. So if
 634                  * the one we're looking at right now has that,
 635                  * return 0. Otherwise, return the difference
 636                  * in length, but since we're looking for the
 637                  * 0-length it's really equivalent to returning
 638                  * the length of the one we're looking at.
 639                  *
 640                  * No content comparison is needed as we assume
 641                  * the content length is zero.
 642                  */
 643                 return ie2[1];
 644         case BSS_CMP_REGULAR:
 645         default:
 646                 /* sort by length first, then by contents */
 647                 if (ie1[1] != ie2[1])
 648                         return ie2[1] - ie1[1];
 649                 return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 650         case BSS_CMP_HIDE_NUL:
 651                 if (ie1[1] != ie2[1])
 652                         return ie2[1] - ie1[1];
 653                 /* this is equivalent to memcmp(zeroes, ie2 + 2, len) */
 654                 for (i = 0; i < ie2[1]; i++)
 655                         if (ie2[i + 2])
 656                                 return -1;
 657                 return 0;
 658         }
 659 }
 660
 661 static bool cfg80211_bss_type_match(u16 capability,
 662                                     enum nl80211_band band,
 663                                     enum ieee80211_bss_type bss_type)
 664 {
 665         bool ret = true;
 666         u16 mask, val;
 667
 668         if (bss_type == IEEE80211_BSS_TYPE_ANY)
 669                 return ret;
 670
 671         if (band == NL80211_BAND_60GHZ) {
 672                 mask = WLAN_CAPABILITY_DMG_TYPE_MASK;
 673                 switch (bss_type) {
 674                 case IEEE80211_BSS_TYPE_ESS:
 675                         val = WLAN_CAPABILITY_DMG_TYPE_AP;
 676                         break;
 677                 case IEEE80211_BSS_TYPE_PBSS:
 678                         val = WLAN_CAPABILITY_DMG_TYPE_PBSS;
 679                         break;
 680                 case IEEE80211_BSS_TYPE_IBSS:
 681                         val = WLAN_CAPABILITY_DMG_TYPE_IBSS;
 682                         break;
 683                 default:
 684                         return false;
 685                 }
 686         } else {
 687                 mask = WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS;
 688                 switch (bss_type) {
 689                 case IEEE80211_BSS_TYPE_ESS:
 690                         val = WLAN_CAPABILITY_ESS;
 691                         break;
 692                 case IEEE80211_BSS_TYPE_IBSS:
 693                         val = WLAN_CAPABILITY_IBSS;
 694                         break;
 695                 case IEEE80211_BSS_TYPE_MBSS:
 696                         val = 0;
 697                         break;
 698                 default:
 699                         return false;
 700                 }
 701         }
 702
 703         ret = ((capability & mask) == val);
 704         return ret;
 705 }
 706
 707 /* Returned bss is reference counted and must be cleaned up appropriately. */
 708 struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
 709                                       struct ieee80211_channel *channel,
 710                                       const u8 *bssid,
 711                                       const u8 *ssid, size_t ssid_len,
 712                                       enum ieee80211_bss_type bss_type,
 713                                       enum ieee80211_privacy privacy)
 714 {
 715         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 716         struct cfg80211_internal_bss *bss, *res = NULL;
 717         unsigned long now = jiffies;
 718         int bss_privacy;
 719
 720         trace_cfg80211_get_bss(wiphy, channel, bssid, ssid, ssid_len, bss_type,
 721                                privacy);
 722
 723         spin_lock_bh(&rdev->bss_lock);
 724
 725         list_for_each_entry(bss, &rdev->bss_list, list) {
 726                 if (!cfg80211_bss_type_match(bss->pub.capability,
 727                                              bss->pub.channel->band, bss_type))
 728                         continue;
 729
 730                 bss_privacy = (bss->pub.capability & WLAN_CAPABILITY_PRIVACY);
 731                 if ((privacy == IEEE80211_PRIVACY_ON && !bss_privacy) ||
 732                     (privacy == IEEE80211_PRIVACY_OFF && bss_privacy))
 733                         continue;
 734                 if (channel && bss->pub.channel != channel)
 735                         continue;
 736                 if (!is_valid_ether_addr(bss->pub.bssid))
 737                         continue;
 738                 /* Don't get expired BSS structs */
 739                 if (time_after(now, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE) &&
 740                     !atomic_read(&bss->hold))
 741                         continue;
 742                 if (is_bss(&bss->pub, bssid, ssid, ssid_len)) {
 743                         res = bss;
 744                         bss_ref_get(rdev, res);
 745                         break;
 746                 }
 747         }
 748
 749         spin_unlock_bh(&rdev->bss_lock);
 750         if (!res)
 751                 return NULL;
 752         trace_cfg80211_return_bss(&res->pub);
 753         return &res->pub;
 754 }
 755 EXPORT_SYMBOL(cfg80211_get_bss);
 756
 757 static void rb_insert_bss(struct cfg80211_registered_device *rdev,
 758                           struct cfg80211_internal_bss *bss)
 759 {
 760         struct rb_node **p = &rdev->bss_tree.rb_node;
 761         struct rb_node *parent = NULL;
 762         struct cfg80211_internal_bss *tbss;
 763         int cmp;
 764
 765         while (*p) {
 766                 parent = *p;
 767                 tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);
 768
 769                 cmp = cmp_bss(&bss->pub, &tbss->pub, BSS_CMP_REGULAR);
 770
 771                 if (WARN_ON(!cmp)) {
 772                         /* will sort of leak this BSS */
 773                         return;
 774                 }
 775
 776                 if (cmp < 0)
 777                         p = &(*p)->rb_left;
 778                 else
 779                         p = &(*p)->rb_right;
 780         }
 781
 782         rb_link_node(&bss->rbn, parent, p);
 783         rb_insert_color(&bss->rbn, &rdev->bss_tree);
 784 }
 785
 786 static struct cfg80211_internal_bss *
 787 rb_find_bss(struct cfg80211_registered_device *rdev,
 788             struct cfg80211_internal_bss *res,
 789             enum bss_compare_mode mode)
 790 {
 791         struct rb_node *n = rdev->bss_tree.rb_node;
 792         struct cfg80211_internal_bss *bss;
 793         int r;
 794
 795         while (n) {
 796                 bss = rb_entry(n, struct cfg80211_internal_bss, rbn);
 797                 r = cmp_bss(&res->pub, &bss->pub, mode);
 798
 799                 if (r == 0)
 800                         return bss;
 801                 else if (r < 0)
 802                         n = n->rb_left;
 803                 else
 804                         n = n->rb_right;
 805         }
 806
 807         return NULL;
 808 }
 809
 810 static bool cfg80211_combine_bsses(struct cfg80211_registered_device *rdev,
 811                                    struct cfg80211_internal_bss *new)
 812 {
 813         const struct cfg80211_bss_ies *ies;
 814         struct cfg80211_internal_bss *bss;
 815         const u8 *ie;
 816         int i, ssidlen;
 817         u8 fold = 0;
 818         u32 n_entries = 0;
 819
 820         ies = rcu_access_pointer(new->pub.beacon_ies);
 821         if (WARN_ON(!ies))
 822                 return false;
 823
 824         ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 825         if (!ie) {
 826                 /* nothing to do */
 827                 return true;
 828         }
 829
 830         ssidlen = ie[1];
 831         for (i = 0; i < ssidlen; i++)
 832                 fold |= ie[2 + i];
 833
 834         if (fold) {
 835                 /* not a hidden SSID */
 836                 return true;
 837         }
 838
 839         /* This is the bad part ... */
 840
 841         list_for_each_entry(bss, &rdev->bss_list, list) {
 842                 /*
 843                  * we're iterating all the entries anyway, so take the
 844                  * opportunity to validate the list length accounting
 845                  */
 846                 n_entries++;
 847
 848                 if (!ether_addr_equal(bss->pub.bssid, new->pub.bssid))
 849                         continue;
 850                 if (bss->pub.channel != new->pub.channel)
 851                         continue;
 852                 if (bss->pub.scan_width != new->pub.scan_width)
 853                         continue;
 854                 if (rcu_access_pointer(bss->pub.beacon_ies))
 855                         continue;
 856                 ies = rcu_access_pointer(bss->pub.ies);
 857                 if (!ies)
 858                         continue;
 859                 ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 860                 if (!ie)
 861                         continue;
 862                 if (ssidlen && ie[1] != ssidlen)
 863                         continue;
 864                 if (WARN_ON_ONCE(bss->pub.hidden_beacon_bss))
 865                         continue;
 866                 if (WARN_ON_ONCE(!list_empty(&bss->hidden_list)))
 867                         list_del(&bss->hidden_list);
 868                 /* combine them */
 869                 list_add(&bss->hidden_list, &new->hidden_list);
 870                 bss->pub.hidden_beacon_bss = &new->pub;
 871                 new->refcount += bss->refcount;
 872                 rcu_assign_pointer(bss->pub.beacon_ies,
 873                                    new->pub.beacon_ies);
 874         }
 875
 876         WARN_ONCE(n_entries != rdev->bss_entries,
 877                   "rdev bss entries[%d]/list[len:%d] corruption\n",
 878                   rdev->bss_entries, n_entries);
 879
 880         return true;
 881 }
 882
 883 /* Returned bss is reference counted and must be cleaned up appropriately. */
 884 static struct cfg80211_internal_bss *
 885 cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 886                     struct cfg80211_internal_bss *tmp,
 887                     bool signal_valid)
 888 {
 889         struct cfg80211_internal_bss *found = NULL;
 890
 891         if (WARN_ON(!tmp->pub.channel))
 892                 return NULL;
 893
 894         tmp->ts = jiffies;
 895
 896         spin_lock_bh(&rdev->bss_lock);
 897
 898         if (WARN_ON(!rcu_access_pointer(tmp->pub.ies))) {
 899                 spin_unlock_bh(&rdev->bss_lock);
 900                 return NULL;
 901         }
 902
 903         found = rb_find_bss(rdev, tmp, BSS_CMP_REGULAR);
 904
 905         if (found) {
 906                 /* Update IEs */
 907                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
 908                         const struct cfg80211_bss_ies *old;
 909
 910                         old = rcu_access_pointer(found->pub.proberesp_ies);
 911
 912                         rcu_assign_pointer(found->pub.proberesp_ies,
 913                                            tmp->pub.proberesp_ies);
 914                         /* Override possible earlier Beacon frame IEs */
 915                         rcu_assign_pointer(found->pub.ies,
 916                                            tmp->pub.proberesp_ies);
 917                         if (old)
 918                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 919                                           rcu_head);
 920                 } else if (rcu_access_pointer(tmp->pub.beacon_ies)) {
 921                         const struct cfg80211_bss_ies *old;
 922                         struct cfg80211_internal_bss *bss;
 923
 924                         if (found->pub.hidden_beacon_bss &&
 925                             !list_empty(&found->hidden_list)) {
 926                                 const struct cfg80211_bss_ies *f;
 927
 928                                 /*
 929                                  * The found BSS struct is one of the probe
 930                                  * response members of a group, but we're
 931                                  * receiving a beacon (beacon_ies in the tmp
 932                                  * bss is used). This can only mean that the
 933                                  * AP changed its beacon from not having an
 934                                  * SSID to showing it, which is confusing so
 935                                  * drop this information.
 936                                  */
 937
 938                                 f = rcu_access_pointer(tmp->pub.beacon_ies);
 939                                 kfree_rcu((struct cfg80211_bss_ies *)f,
 940                                           rcu_head);
 941                                 goto drop;
 942                         }
 943
 944                         old = rcu_access_pointer(found->pub.beacon_ies);
 945
 946                         rcu_assign_pointer(found->pub.beacon_ies,
 947                                            tmp->pub.beacon_ies);
 948
 949                         /* Override IEs if they were from a beacon before */
 950                         if (old == rcu_access_pointer(found->pub.ies))
 951                                 rcu_assign_pointer(found->pub.ies,
 952                                                    tmp->pub.beacon_ies);
 953
 954                         /* Assign beacon IEs to all sub entries */
 955                         list_for_each_entry(bss, &found->hidden_list,
 956                                             hidden_list) {
 957                                 const struct cfg80211_bss_ies *ies;
 958
 959                                 ies = rcu_access_pointer(bss->pub.beacon_ies);
 960                                 WARN_ON(ies != old);
 961
 962                                 rcu_assign_pointer(bss->pub.beacon_ies,
 963                                                    tmp->pub.beacon_ies);
 964                         }
 965
 966                         if (old)
 967                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 968                                           rcu_head);
 969                 }
 970
 971                 found->pub.beacon_interval = tmp->pub.beacon_interval;
 972                 /*
 973                  * don't update the signal if beacon was heard on
 974                  * adjacent channel.
 975                  */
 976                 if (signal_valid)
 977                         found->pub.signal = tmp->pub.signal;
 978                 found->pub.capability = tmp->pub.capability;
 979                 found->ts = tmp->ts;
 980                 found->ts_boottime = tmp->ts_boottime;
 981                 found->parent_tsf = tmp->parent_tsf;
 982                 ether_addr_copy(found->parent_bssid, tmp->parent_bssid);
 983         } else {
 984                 struct cfg80211_internal_bss *new;
 985                 struct cfg80211_internal_bss *hidden;
 986                 struct cfg80211_bss_ies *ies;
 987
 988                 /*
 989                  * create a copy -- the "res" variable that is passed in
 990                  * is allocated on the stack since it's not needed in the
 991                  * more common case of an update
 992                  */
 993                 new = kzalloc(sizeof(*new) + rdev->wiphy.bss_priv_size,
 994                               GFP_ATOMIC);
 995                 if (!new) {
 996                         ies = (void *)rcu_dereference(tmp->pub.beacon_ies);
 997                         if (ies)
 998                                 kfree_rcu(ies, rcu_head);
 999                         ies = (void *)rcu_dereference(tmp->pub.proberesp_ies);
1000                         if (ies)
1001                                 kfree_rcu(ies, rcu_head);
1002                         goto drop;
1003                 }
1004                 memcpy(new, tmp, sizeof(*new));
1005                 new->refcount = 1;
1006                 INIT_LIST_HEAD(&new->hidden_list);
1007
1008                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
1009                         hidden = rb_find_bss(rdev, tmp, BSS_CMP_HIDE_ZLEN);
1010                         if (!hidden)
1011                                 hidden = rb_find_bss(rdev, tmp,
1012                                                      BSS_CMP_HIDE_NUL);
1013                         if (hidden) {
1014                                 new->pub.hidden_beacon_bss = &hidden->pub;
1015                                 list_add(&new->hidden_list,
1016                                          &hidden->hidden_list);
1017                                 hidden->refcount++;
1018                                 rcu_assign_pointer(new->pub.beacon_ies,
1019                                                    hidden->pub.beacon_ies);
1020                         }
1021                 } else {
1022                         /*
1023                          * Ok so we found a beacon, and don't have an entry. If
1024                          * it's a beacon with hidden SSID, we might be in for an
1025                          * expensive search for any probe responses that should
1026                          * be grouped with this beacon for updates ...
1027                          */
1028                         if (!cfg80211_combine_bsses(rdev, new)) {
1029                                 bss_ref_put(rdev, new);
1030                                 goto drop;
1031                         }
1032                 }
1033
1034                 if (rdev->bss_entries >= bss_entries_limit &&
1035                     !cfg80211_bss_expire_oldest(rdev)) {
1036                         bss_ref_put(rdev, new);
1037                         goto drop;
1038                 }
1039
1040                 list_add_tail(&new->list, &rdev->bss_list);
1041                 rdev->bss_entries++;
1042                 rb_insert_bss(rdev, new);
1043                 found = new;
1044         }
1045
1046         rdev->bss_generation++;
1047         bss_ref_get(rdev, found);
1048         spin_unlock_bh(&rdev->bss_lock);
1049
1050         return found;
1051  drop:
1052         spin_unlock_bh(&rdev->bss_lock);
1053         return NULL;
1054 }
1055
1056 /*
1057  * Update RX channel information based on the available frame payload
1058  * information. This is mainly for the 2.4 GHz band where frames can be received
1059  * from neighboring channels and the Beacon frames use the DSSS Parameter Set
1060  * element to indicate the current (transmitting) channel, but this might also
1061  * be needed on other bands if RX frequency does not match with the actual
1062  * operating channel of a BSS.
1063  */
1064 static struct ieee80211_channel *
1065 cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
1066                          struct ieee80211_channel *channel,
1067                          enum nl80211_bss_scan_width scan_width)
1068 {
1069         const u8 *tmp;
1070         u32 freq;
1071         int channel_number = -1;
1072         struct ieee80211_channel *alt_channel;
1073
1074         tmp = cfg80211_find_ie(WLAN_EID_DS_PARAMS, ie, ielen);
1075         if (tmp && tmp[1] == 1) {
1076                 channel_number = tmp[2];
1077         } else {
1078                 tmp = cfg80211_find_ie(WLAN_EID_HT_OPERATION, ie, ielen);
1079                 if (tmp && tmp[1] >= sizeof(struct ieee80211_ht_operation)) {
1080                         struct ieee80211_ht_operation *htop = (void *)(tmp + 2);
1081
1082                         channel_number = htop->primary_chan;
1083                 }
1084         }
1085
1086         if (channel_number < 0) {
1087                 /* No channel information in frame payload */
1088                 return channel;
1089         }
1090
1091         freq = ieee80211_channel_to_frequency(channel_number, channel->band);
1092         alt_channel = ieee80211_get_channel(wiphy, freq);
1093         if (!alt_channel) {
1094                 if (channel->band == NL80211_BAND_2GHZ) {
1095                         /*
1096                          * Better not allow unexpected channels when that could
1097                          * be going beyond the 1-11 range (e.g., discovering
1098                          * BSS on channel 12 when radio is configured for
1099                          * channel 11.
1100                          */
1101                         return NULL;
1102                 }
1103
1104                 /* No match for the payload channel number - ignore it */
1105                 return channel;
1106         }
1107
1108         if (scan_width == NL80211_BSS_CHAN_WIDTH_10 ||
1109             scan_width == NL80211_BSS_CHAN_WIDTH_5) {
1110                 /*
1111                  * Ignore channel number in 5 and 10 MHz channels where there
1112                  * may not be an n:1 or 1:n mapping between frequencies and
1113                  * channel numbers.
1114                  */
1115                 return channel;
1116         }
1117
1118         /*
1119          * Use the channel determined through the payload channel number
1120          * instead of the RX channel reported by the driver.
1121          */
1122         if (alt_channel->flags & IEEE80211_CHAN_DISABLED)
1123                 return NULL;
1124         return alt_channel;
1125 }
1126
1127 /* Returned bss is reference counted and must be cleaned up appropriately. */
1128 struct cfg80211_bss *
1129 cfg80211_inform_bss_data(struct wiphy *wiphy,
1130                          struct cfg80211_inform_bss *data,
1131                          enum cfg80211_bss_frame_type ftype,
1132                          const u8 *bssid, u64 tsf, u16 capability,
1133                          u16 beacon_interval, const u8 *ie, size_t ielen,
1134                          gfp_t gfp)
1135 {
1136         struct cfg80211_bss_ies *ies;
1137         struct ieee80211_channel *channel;
1138         struct cfg80211_internal_bss tmp = {}, *res;
1139         int bss_type;
1140         bool signal_valid;
1141
1142         if (WARN_ON(!wiphy))
1143                 return NULL;
1144
1145         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
1146                     (data->signal < 0 || data->signal > 100)))
1147                 return NULL;
1148
1149         channel = cfg80211_get_bss_channel(wiphy, ie, ielen, data->chan,
1150                                            data->scan_width);
1151         if (!channel)
1152                 return NULL;
1153
1154         memcpy(tmp.pub.bssid, bssid, ETH_ALEN);
1155         tmp.pub.channel = channel;
1156         tmp.pub.scan_width = data->scan_width;
1157         tmp.pub.signal = data->signal;
1158         tmp.pub.beacon_interval = beacon_interval;
1159         tmp.pub.capability = capability;
1160         tmp.ts_boottime = data->boottime_ns;
1161
1162         /*
1163          * If we do not know here whether the IEs are from a Beacon or Probe
1164          * Response frame, we need to pick one of the options and only use it
1165          * with the driver that does not provide the full Beacon/Probe Response
1166          * frame. Use Beacon frame pointer to avoid indicating that this should
1167          * override the IEs pointer should we have received an earlier
1168          * indication of Probe Response data.
1169          */
1170         ies = kzalloc(sizeof(*ies) + ielen, gfp);
1171         if (!ies)
1172                 return NULL;
1173         ies->len = ielen;
1174         ies->tsf = tsf;
1175         ies->from_beacon = false;
1176         memcpy(ies->data, ie, ielen);
1177
1178         switch (ftype) {
1179         case CFG80211_BSS_FTYPE_BEACON:
1180                 ies->from_beacon = true;
1181                 /* fall through to assign */
1182         case CFG80211_BSS_FTYPE_UNKNOWN:
1183                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1184                 break;
1185         case CFG80211_BSS_FTYPE_PRESP:
1186                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1187                 break;
1188         }
1189         rcu_assign_pointer(tmp.pub.ies, ies);
1190
1191         signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
1192                 wiphy->max_adj_channel_rssi_comp;
1193         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1194         if (!res)
1195                 return NULL;
1196
1197         if (channel->band == NL80211_BAND_60GHZ) {
1198                 bss_type = res->pub.capability & WLAN_CAPABILITY_DMG_TYPE_MASK;
1199                 if (bss_type == WLAN_CAPABILITY_DMG_TYPE_AP ||
1200                     bss_type == WLAN_CAPABILITY_DMG_TYPE_PBSS)
1201                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1202         } else {
1203                 if (res->pub.capability & WLAN_CAPABILITY_ESS)
1204                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1205         }
1206
1207         trace_cfg80211_return_bss(&res->pub);
1208         /* cfg80211_bss_update gives us a referenced result */
1209         return &res->pub;
1210 }
1211 EXPORT_SYMBOL(cfg80211_inform_bss_data);
1212
1213 /* cfg80211_inform_bss_width_frame helper */
1214 struct cfg80211_bss *
1215 cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
1216                                struct cfg80211_inform_bss *data,
1217                                struct ieee80211_mgmt *mgmt, size_t len,
1218                                gfp_t gfp)
1219
1220 {
1221         struct cfg80211_internal_bss tmp = {}, *res;
1222         struct cfg80211_bss_ies *ies;
1223         struct ieee80211_channel *channel;
1224         bool signal_valid;
1225         size_t ielen = len - offsetof(struct ieee80211_mgmt,
1226                                       u.probe_resp.variable);
1227         int bss_type;
1228
1229         BUILD_BUG_ON(offsetof(struct ieee80211_mgmt, u.probe_resp.variable) !=
1230                         offsetof(struct ieee80211_mgmt, u.beacon.variable));
1231
1232         trace_cfg80211_inform_bss_frame(wiphy, data, mgmt, len);
1233
1234         if (WARN_ON(!mgmt))
1235                 return NULL;
1236
1237         if (WARN_ON(!wiphy))
1238                 return NULL;
1239
1240         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
1241                     (data->signal < 0 || data->signal > 100)))
1242                 return NULL;
1243
1244         if (WARN_ON(len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
1245                 return NULL;
1246
1247         channel = cfg80211_get_bss_channel(wiphy, mgmt->u.beacon.variable,
1248                                            ielen, data->chan, data->scan_width);
1249         if (!channel)
1250                 return NULL;
1251
1252         ies = kzalloc(sizeof(*ies) + ielen, gfp);
1253         if (!ies)
1254                 return NULL;
1255         ies->len = ielen;
1256         ies->tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
1257         ies->from_beacon = ieee80211_is_beacon(mgmt->frame_control);
1258         memcpy(ies->data, mgmt->u.probe_resp.variable, ielen);
1259
1260         if (ieee80211_is_probe_resp(mgmt->frame_control))
1261                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1262         else
1263                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1264         rcu_assign_pointer(tmp.pub.ies, ies);
1265
1266         memcpy(tmp.pub.bssid, mgmt->bssid, ETH_ALEN);
1267         tmp.pub.channel = channel;
1268         tmp.pub.scan_width = data->scan_width;
1269         tmp.pub.signal = data->signal;
1270         tmp.pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
1271         tmp.pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
1272         tmp.ts_boottime = data->boottime_ns;
1273         tmp.parent_tsf = data->parent_tsf;
1274         ether_addr_copy(tmp.parent_bssid, data->parent_bssid);
1275
1276         signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
1277                 wiphy->max_adj_channel_rssi_comp;
1278         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1279         if (!res)
1280                 return NULL;
1281
1282         if (channel->band == NL80211_BAND_60GHZ) {
1283                 bss_type = res->pub.capability & WLAN_CAPABILITY_DMG_TYPE_MASK;
1284                 if (bss_type == WLAN_CAPABILITY_DMG_TYPE_AP ||
1285                     bss_type == WLAN_CAPABILITY_DMG_TYPE_PBSS)
1286                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1287         } else {
1288                 if (res->pub.capability & WLAN_CAPABILITY_ESS)
1289                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1290         }
1291
1292         trace_cfg80211_return_bss(&res->pub);
1293         /* cfg80211_bss_update gives us a referenced result */
1294         return &res->pub;
1295 }
1296 EXPORT_SYMBOL(cfg80211_inform_bss_frame_data);
1297
1298 void cfg80211_ref_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1299 {
1300         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1301         struct cfg80211_internal_bss *bss;
1302
1303         if (!pub)
1304                 return;
1305
1306         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1307
1308         spin_lock_bh(&rdev->bss_lock);
1309         bss_ref_get(rdev, bss);
1310         spin_unlock_bh(&rdev->bss_lock);
1311 }
1312 EXPORT_SYMBOL(cfg80211_ref_bss);
1313
1314 void cfg80211_put_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1315 {
1316         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1317         struct cfg80211_internal_bss *bss;
1318
1319         if (!pub)
1320                 return;
1321
1322         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1323
1324         spin_lock_bh(&rdev->bss_lock);
1325         bss_ref_put(rdev, bss);
1326         spin_unlock_bh(&rdev->bss_lock);
1327 }
1328 EXPORT_SYMBOL(cfg80211_put_bss);
1329
1330 void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1331 {
1332         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1333         struct cfg80211_internal_bss *bss;
1334
1335         if (WARN_ON(!pub))
1336                 return;
1337
1338         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1339
1340         spin_lock_bh(&rdev->bss_lock);
1341         if (!list_empty(&bss->list)) {
1342                 if (__cfg80211_unlink_bss(rdev, bss))
1343                         rdev->bss_generation++;
1344         }
1345         spin_unlock_bh(&rdev->bss_lock);
1346 }
1347 EXPORT_SYMBOL(cfg80211_unlink_bss);
1348
1349 #ifdef CONFIG_CFG80211_WEXT
1350 static struct cfg80211_registered_device *
1351 cfg80211_get_dev_from_ifindex(struct net *net, int ifindex)
1352 {
1353         struct cfg80211_registered_device *rdev;
1354         struct net_device *dev;
1355
1356         ASSERT_RTNL();
1357
1358         dev = dev_get_by_index(net, ifindex);
1359         if (!dev)
1360                 return ERR_PTR(-ENODEV);
1361         if (dev->ieee80211_ptr)
1362                 rdev = wiphy_to_rdev(dev->ieee80211_ptr->wiphy);
1363         else
1364                 rdev = ERR_PTR(-ENODEV);
1365         dev_put(dev);
1366         return rdev;
1367 }
1368
1369 int cfg80211_wext_siwscan(struct net_device *dev,
1370                           struct iw_request_info *info,
1371                           union iwreq_data *wrqu, char *extra)
1372 {
1373         struct cfg80211_registered_device *rdev;
1374         struct wiphy *wiphy;
1375         struct iw_scan_req *wreq = NULL;
1376         struct cfg80211_scan_request *creq = NULL;
1377         int i, err, n_channels = 0;
1378         enum nl80211_band band;
1379
1380         if (!netif_running(dev))
1381                 return -ENETDOWN;
1382
1383         if (wrqu->data.length == sizeof(struct iw_scan_req))
1384                 wreq = (struct iw_scan_req *)extra;
1385
1386         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1387
1388         if (IS_ERR(rdev))
1389                 return PTR_ERR(rdev);
1390
1391         if (rdev->scan_req || rdev->scan_msg) {
1392                 err = -EBUSY;
1393                 goto out;
1394         }
1395
1396         wiphy = &rdev->wiphy;
1397
1398         /* Determine number of channels, needed to allocate creq */
1399         if (wreq && wreq->num_channels)
1400                 n_channels = wreq->num_channels;
1401         else
1402                 n_channels = ieee80211_get_num_supported_channels(wiphy);
1403
1404         creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
1405                        n_channels * sizeof(void *),
1406                        GFP_ATOMIC);
1407         if (!creq) {
1408                 err = -ENOMEM;
1409                 goto out;
1410         }
1411
1412         creq->wiphy = wiphy;
1413         creq->wdev = dev->ieee80211_ptr;
1414         /* SSIDs come after channels */
1415         creq->ssids = (void *)&creq->channels[n_channels];
1416         creq->n_channels = n_channels;
1417         creq->n_ssids = 1;
1418         creq->scan_start = jiffies;
1419
1420         /* translate "Scan on frequencies" request */
1421         i = 0;
1422         for (band = 0; band < NUM_NL80211_BANDS; band++) {
1423                 int j;
1424
1425                 if (!wiphy->bands[band])
1426                         continue;
1427
1428                 for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
1429                         /* ignore disabled channels */
1430                         if (wiphy->bands[band]->channels[j].flags &
1431                                                 IEEE80211_CHAN_DISABLED)
1432                                 continue;
1433
1434                         /* If we have a wireless request structure and the
1435                          * wireless request specifies frequencies, then search
1436                          * for the matching hardware channel.
1437                          */
1438                         if (wreq && wreq->num_channels) {
1439                                 int k;
1440                                 int wiphy_freq = wiphy->bands[band]->channels[j].center_freq;
1441                                 for (k = 0; k < wreq->num_channels; k++) {
1442                                         struct iw_freq *freq =
1443                                                 &wreq->channel_list[k];
1444                                         int wext_freq =
1445                                                 cfg80211_wext_freq(freq);
1446
1447                                         if (wext_freq == wiphy_freq)
1448                                                 goto wext_freq_found;
1449                                 }
1450                                 goto wext_freq_not_found;
1451                         }
1452
1453                 wext_freq_found:
1454                         creq->channels[i] = &wiphy->bands[band]->channels[j];
1455                         i++;
1456                 wext_freq_not_found: ;
1457                 }
1458         }
1459         /* No channels found? */
1460         if (!i) {
1461                 err = -EINVAL;
1462                 goto out;
1463         }
1464
1465         /* Set real number of channels specified in creq->channels[] */
1466         creq->n_channels = i;
1467
1468         /* translate "Scan for SSID" request */
1469         if (wreq) {
1470                 if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
1471                         if (wreq->essid_len > IEEE80211_MAX_SSID_LEN) {
1472                                 err = -EINVAL;
1473                                 goto out;
1474                         }
1475                         memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
1476                         creq->ssids[0].ssid_len = wreq->essid_len;
1477                 }
1478                 if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE)
1479                         creq->n_ssids = 0;
1480         }
1481
1482         for (i = 0; i < NUM_NL80211_BANDS; i++)
1483                 if (wiphy->bands[i])
1484                         creq->rates[i] = (1 << wiphy->bands[i]->n_bitrates) - 1;
1485
1486         eth_broadcast_addr(creq->bssid);
1487
1488         rdev->scan_req = creq;
1489         err = rdev_scan(rdev, creq);
1490         if (err) {
1491                 rdev->scan_req = NULL;
1492                 /* creq will be freed below */
1493         } else {
1494                 nl80211_send_scan_start(rdev, dev->ieee80211_ptr);
1495                 /* creq now owned by driver */
1496                 creq = NULL;
1497                 dev_hold(dev);
1498         }
1499  out:
1500         kfree(creq);
1501         return err;
1502 }
1503 EXPORT_WEXT_HANDLER(cfg80211_wext_siwscan);
1504
1505 static char *ieee80211_scan_add_ies(struct iw_request_info *info,
1506                                     const struct cfg80211_bss_ies *ies,
1507                                     char *current_ev, char *end_buf)
1508 {
1509         const u8 *pos, *end, *next;
1510         struct iw_event iwe;
1511
1512         if (!ies)
1513                 return current_ev;
1514
1515         /*
1516          * If needed, fragment the IEs buffer (at IE boundaries) into short
1517          * enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
1518          */
1519         pos = ies->data;
1520         end = pos + ies->len;
1521
1522         while (end - pos > IW_GENERIC_IE_MAX) {
1523                 next = pos + 2 + pos[1];
1524                 while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
1525                         next = next + 2 + next[1];
1526
1527                 memset(&iwe, 0, sizeof(iwe));
1528                 iwe.cmd = IWEVGENIE;
1529                 iwe.u.data.length = next - pos;
1530                 current_ev = iwe_stream_add_point_check(info, current_ev,
1531                                                         end_buf, &iwe,
1532                                                         (void *)pos);
1533                 if (IS_ERR(current_ev))
1534                         return current_ev;
1535                 pos = next;
1536         }
1537
1538         if (end > pos) {
1539                 memset(&iwe, 0, sizeof(iwe));
1540                 iwe.cmd = IWEVGENIE;
1541                 iwe.u.data.length = end - pos;
1542                 current_ev = iwe_stream_add_point_check(info, current_ev,
1543                                                         end_buf, &iwe,
1544                                                         (void *)pos);
1545                 if (IS_ERR(current_ev))
1546                         return current_ev;
1547         }
1548
1549         return current_ev;
1550 }
1551
1552 static char *
1553 ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,
1554               struct cfg80211_internal_bss *bss, char *current_ev,
1555               char *end_buf)
1556 {
1557         const struct cfg80211_bss_ies *ies;
1558         struct iw_event iwe;
1559         const u8 *ie;
1560         u8 buf[50];
1561         u8 *cfg, *p, *tmp;
1562         int rem, i, sig;
1563         bool ismesh = false;
1564
1565         memset(&iwe, 0, sizeof(iwe));
1566         iwe.cmd = SIOCGIWAP;
1567         iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
1568         memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN);
1569         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1570                                                 IW_EV_ADDR_LEN);
1571         if (IS_ERR(current_ev))
1572                 return current_ev;
1573
1574         memset(&iwe, 0, sizeof(iwe));
1575         iwe.cmd = SIOCGIWFREQ;
1576         iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq);
1577         iwe.u.freq.e = 0;
1578         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1579                                                 IW_EV_FREQ_LEN);
1580         if (IS_ERR(current_ev))
1581                 return current_ev;
1582
1583         memset(&iwe, 0, sizeof(iwe));
1584         iwe.cmd = SIOCGIWFREQ;
1585         iwe.u.freq.m = bss->pub.channel->center_freq;
1586         iwe.u.freq.e = 6;
1587         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1588                                                 IW_EV_FREQ_LEN);
1589         if (IS_ERR(current_ev))
1590                 return current_ev;
1591
1592         if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) {
1593                 memset(&iwe, 0, sizeof(iwe));
1594                 iwe.cmd = IWEVQUAL;
1595                 iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED |
1596                                      IW_QUAL_NOISE_INVALID |
1597                                      IW_QUAL_QUAL_UPDATED;
1598                 switch (wiphy->signal_type) {
1599                 case CFG80211_SIGNAL_TYPE_MBM:
1600                         sig = bss->pub.signal / 100;
1601                         iwe.u.qual.level = sig;
1602                         iwe.u.qual.updated |= IW_QUAL_DBM;
1603                         if (sig < -110)         /* rather bad */
1604                                 sig = -110;
1605                         else if (sig > -40)     /* perfect */
1606                                 sig = -40;
1607                         /* will give a range of 0 .. 70 */
1608                         iwe.u.qual.qual = sig + 110;
1609                         break;
1610                 case CFG80211_SIGNAL_TYPE_UNSPEC:
1611                         iwe.u.qual.level = bss->pub.signal;
1612                         /* will give range 0 .. 100 */
1613                         iwe.u.qual.qual = bss->pub.signal;
1614                         break;
1615                 default:
1616                         /* not reached */
1617                         break;
1618                 }
1619                 current_ev = iwe_stream_add_event_check(info, current_ev,
1620                                                         end_buf, &iwe,
1621                                                         IW_EV_QUAL_LEN);
1622                 if (IS_ERR(current_ev))
1623                         return current_ev;
1624         }
1625
1626         memset(&iwe, 0, sizeof(iwe));
1627         iwe.cmd = SIOCGIWENCODE;
1628         if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY)
1629                 iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
1630         else
1631                 iwe.u.data.flags = IW_ENCODE_DISABLED;
1632         iwe.u.data.length = 0;
1633         current_ev = iwe_stream_add_point_check(info, current_ev, end_buf,
1634                                                 &iwe, "");
1635         if (IS_ERR(current_ev))
1636                 return current_ev;
1637
1638         rcu_read_lock();
1639         ies = rcu_dereference(bss->pub.ies);
1640         rem = ies->len;
1641         ie = ies->data;
1642
1643         while (rem >= 2) {
1644                 /* invalid data */
1645                 if (ie[1] > rem - 2)
1646                         break;
1647
1648                 switch (ie[0]) {
1649                 case WLAN_EID_SSID:
1650                         memset(&iwe, 0, sizeof(iwe));
1651                         iwe.cmd = SIOCGIWESSID;
1652                         iwe.u.data.length = ie[1];
1653                         iwe.u.data.flags = 1;
1654                         current_ev = iwe_stream_add_point_check(info,
1655                                                                 current_ev,
1656                                                                 end_buf, &iwe,
1657                                                                 (u8 *)ie + 2);
1658                         if (IS_ERR(current_ev))
1659                                 goto unlock;
1660                         break;
1661                 case WLAN_EID_MESH_ID:
1662                         memset(&iwe, 0, sizeof(iwe));
1663                         iwe.cmd = SIOCGIWESSID;
1664                         iwe.u.data.length = ie[1];
1665                         iwe.u.data.flags = 1;
1666                         current_ev = iwe_stream_add_point_check(info,
1667                                                                 current_ev,
1668                                                                 end_buf, &iwe,
1669                                                                 (u8 *)ie + 2);
1670                         if (IS_ERR(current_ev))
1671                                 goto unlock;
1672                         break;
1673                 case WLAN_EID_MESH_CONFIG:
1674                         ismesh = true;
1675                         if (ie[1] != sizeof(struct ieee80211_meshconf_ie))
1676                                 break;
1677                         cfg = (u8 *)ie + 2;
1678                         memset(&iwe, 0, sizeof(iwe));
1679                         iwe.cmd = IWEVCUSTOM;
1680                         sprintf(buf, "Mesh Network Path Selection Protocol ID: "
1681                                 "0x%02X", cfg[0]);
1682                         iwe.u.data.length = strlen(buf);
1683                         current_ev = iwe_stream_add_point_check(info,
1684                                                                 current_ev,
1685                                                                 end_buf,
1686                                                                 &iwe, buf);
1687                         if (IS_ERR(current_ev))
1688                                 goto unlock;
1689                         sprintf(buf, "Path Selection Metric ID: 0x%02X",
1690                                 cfg[1]);
1691                         iwe.u.data.length = strlen(buf);
1692                         current_ev = iwe_stream_add_point_check(info,
1693                                                                 current_ev,
1694                                                                 end_buf,
1695                                                                 &iwe, buf);
1696                         if (IS_ERR(current_ev))
1697                                 goto unlock;
1698                         sprintf(buf, "Congestion Control Mode ID: 0x%02X",
1699                                 cfg[2]);
1700                         iwe.u.data.length = strlen(buf);
1701                         current_ev = iwe_stream_add_point_check(info,
1702                                                                 current_ev,
1703                                                                 end_buf,
1704                                                                 &iwe, buf);
1705                         if (IS_ERR(current_ev))
1706                                 goto unlock;
1707                         sprintf(buf, "Synchronization ID: 0x%02X", cfg[3]);
1708                         iwe.u.data.length = strlen(buf);
1709                         current_ev = iwe_stream_add_point_check(info,
1710                                                                 current_ev,
1711                                                                 end_buf,
1712                                                                 &iwe, buf);
1713                         if (IS_ERR(current_ev))
1714                                 goto unlock;
1715                         sprintf(buf, "Authentication ID: 0x%02X", cfg[4]);
1716                         iwe.u.data.length = strlen(buf);
1717                         current_ev = iwe_stream_add_point_check(info,
1718                                                                 current_ev,
1719                                                                 end_buf,
1720                                                                 &iwe, buf);
1721                         if (IS_ERR(current_ev))
1722                                 goto unlock;
1723                         sprintf(buf, "Formation Info: 0x%02X", cfg[5]);
1724                         iwe.u.data.length = strlen(buf);
1725                         current_ev = iwe_stream_add_point_check(info,
1726                                                                 current_ev,
1727                                                                 end_buf,
1728                                                                 &iwe, buf);
1729                         if (IS_ERR(current_ev))
1730                                 goto unlock;
1731                         sprintf(buf, "Capabilities: 0x%02X", cfg[6]);
1732                         iwe.u.data.length = strlen(buf);
1733                         current_ev = iwe_stream_add_point_check(info,
1734                                                                 current_ev,
1735                                                                 end_buf,
1736                                                                 &iwe, buf);
1737                         if (IS_ERR(current_ev))
1738                                 goto unlock;
1739                         break;
1740                 case WLAN_EID_SUPP_RATES:
1741                 case WLAN_EID_EXT_SUPP_RATES:
1742                         /* display all supported rates in readable format */
1743                         p = current_ev + iwe_stream_lcp_len(info);
1744
1745                         memset(&iwe, 0, sizeof(iwe));
1746                         iwe.cmd = SIOCGIWRATE;
1747                         /* Those two flags are ignored... */
1748                         iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;
1749
1750                         for (i = 0; i < ie[1]; i++) {
1751                                 iwe.u.bitrate.value =
1752                                         ((ie[i + 2] & 0x7f) * 500000);
1753                                 tmp = p;
1754                                 p = iwe_stream_add_value(info, current_ev, p,
1755                                                          end_buf, &iwe,
1756                                                          IW_EV_PARAM_LEN);
1757                                 if (p == tmp) {
1758                                         current_ev = ERR_PTR(-E2BIG);
1759                                         goto unlock;
1760                                 }
1761                         }
1762                         current_ev = p;
1763                         break;
1764                 }
1765                 rem -= ie[1] + 2;
1766                 ie += ie[1] + 2;
1767         }
1768
1769         if (bss->pub.capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS) ||
1770             ismesh) {
1771                 memset(&iwe, 0, sizeof(iwe));
1772                 iwe.cmd = SIOCGIWMODE;
1773                 if (ismesh)
1774                         iwe.u.mode = IW_MODE_MESH;
1775                 else if (bss->pub.capability & WLAN_CAPABILITY_ESS)
1776                         iwe.u.mode = IW_MODE_MASTER;
1777                 else
1778                         iwe.u.mode = IW_MODE_ADHOC;
1779                 current_ev = iwe_stream_add_event_check(info, current_ev,
1780                                                         end_buf, &iwe,
1781                                                         IW_EV_UINT_LEN);
1782                 if (IS_ERR(current_ev))
1783                         goto unlock;
1784         }
1785
1786         memset(&iwe, 0, sizeof(iwe));
1787         iwe.cmd = IWEVCUSTOM;
1788         sprintf(buf, "tsf=%016llx", (unsigned long long)(ies->tsf));
1789         iwe.u.data.length = strlen(buf);
1790         current_ev = iwe_stream_add_point_check(info, current_ev, end_buf,
1791                                                 &iwe, buf);
1792         if (IS_ERR(current_ev))
1793                 goto unlock;
1794         memset(&iwe, 0, sizeof(iwe));
1795         iwe.cmd = IWEVCUSTOM;
1796         sprintf(buf, " Last beacon: %ums ago",
1797                 elapsed_jiffies_msecs(bss->ts));
1798         iwe.u.data.length = strlen(buf);
1799         current_ev = iwe_stream_add_point_check(info, current_ev,
1800                                                 end_buf, &iwe, buf);
1801         if (IS_ERR(current_ev))
1802                 goto unlock;
1803
1804         current_ev = ieee80211_scan_add_ies(info, ies, current_ev, end_buf);
1805
1806  unlock:
1807         rcu_read_unlock();
1808         return current_ev;
1809 }
1810
1811
1812 static int ieee80211_scan_results(struct cfg80211_registered_device *rdev,
1813                                   struct iw_request_info *info,
1814                                   char *buf, size_t len)
1815 {
1816         char *current_ev = buf;
1817         char *end_buf = buf + len;
1818         struct cfg80211_internal_bss *bss;
1819         int err = 0;
1820
1821         spin_lock_bh(&rdev->bss_lock);
1822         cfg80211_bss_expire(rdev);
1823
1824         list_for_each_entry(bss, &rdev->bss_list, list) {
1825                 if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
1826                         err = -E2BIG;
1827                         break;
1828                 }
1829                 current_ev = ieee80211_bss(&rdev->wiphy, info, bss,
1830                                            current_ev, end_buf);
1831                 if (IS_ERR(current_ev)) {
1832                         err = PTR_ERR(current_ev);
1833                         break;
1834                 }
1835         }
1836         spin_unlock_bh(&rdev->bss_lock);
1837
1838         if (err)
1839                 return err;
1840         return current_ev - buf;
1841 }
1842
1843
1844 int cfg80211_wext_giwscan(struct net_device *dev,
1845                           struct iw_request_info *info,
1846                           struct iw_point *data, char *extra)
1847 {
1848         struct cfg80211_registered_device *rdev;
1849         int res;
1850
1851         if (!netif_running(dev))
1852                 return -ENETDOWN;
1853
1854         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1855
1856         if (IS_ERR(rdev))
1857                 return PTR_ERR(rdev);
1858
1859         if (rdev->scan_req || rdev->scan_msg)
1860                 return -EAGAIN;
1861
1862         res = ieee80211_scan_results(rdev, info, extra, data->length);
1863         data->length = 0;
1864         if (res >= 0) {
1865                 data->length = res;
1866                 res = 0;
1867         }
1868
1869         return res;
1870 }
1871 EXPORT_WEXT_HANDLER(cfg80211_wext_giwscan);
1872 #endif