net/wireless/scan.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * cfg80211 scan result handling
   4  *
   5  * Copyright 2008 Johannes Berg <[email protected]>
   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         /* match_offset can't be smaller than 2, unless match_len is
 488          * zero, in which case match_offset must be zero as well.
 489          */
 490         if (WARN_ON((match_len && match_offset < 2) ||
 491                     (!match_len && match_offset)))
 492                 return NULL;
 493
 494         while (len >= 2 && len >= ies[1] + 2) {
 495                 if ((ies[0] == eid) &&
 496                     (ies[1] + 2 >= match_offset + match_len) &&
 497                     !memcmp(ies + match_offset, match, match_len))
 498                         return ies;
 499
 500                 len -= ies[1] + 2;
 501                 ies += ies[1] + 2;
 502         }
 503
 504         return NULL;
 505 }
 506 EXPORT_SYMBOL(cfg80211_find_ie_match);
 507
 508 const u8 *cfg80211_find_vendor_ie(unsigned int oui, int oui_type,
 509                                   const u8 *ies, int len)
 510 {
 511         const u8 *ie;
 512         u8 match[] = { oui >> 16, oui >> 8, oui, oui_type };
 513         int match_len = (oui_type < 0) ? 3 : sizeof(match);
 514
 515         if (WARN_ON(oui_type > 0xff))
 516                 return NULL;
 517
 518         ie = cfg80211_find_ie_match(WLAN_EID_VENDOR_SPECIFIC, ies, len,
 519                                     match, match_len, 2);
 520
 521         if (ie && (ie[1] < 4))
 522                 return NULL;
 523
 524         return ie;
 525 }
 526 EXPORT_SYMBOL(cfg80211_find_vendor_ie);
 527
 528 static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
 529                    const u8 *ssid, size_t ssid_len)
 530 {
 531         const struct cfg80211_bss_ies *ies;
 532         const u8 *ssidie;
 533
 534         if (bssid && !ether_addr_equal(a->bssid, bssid))
 535                 return false;
 536
 537         if (!ssid)
 538                 return true;
 539
 540         ies = rcu_access_pointer(a->ies);
 541         if (!ies)
 542                 return false;
 543         ssidie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 544         if (!ssidie)
 545                 return false;
 546         if (ssidie[1] != ssid_len)
 547                 return false;
 548         return memcmp(ssidie + 2, ssid, ssid_len) == 0;
 549 }
 550
 551 /**
 552  * enum bss_compare_mode - BSS compare mode
 553  * @BSS_CMP_REGULAR: regular compare mode (for insertion and normal find)
 554  * @BSS_CMP_HIDE_ZLEN: find hidden SSID with zero-length mode
 555  * @BSS_CMP_HIDE_NUL: find hidden SSID with NUL-ed out mode
 556  */
 557 enum bss_compare_mode {
 558         BSS_CMP_REGULAR,
 559         BSS_CMP_HIDE_ZLEN,
 560         BSS_CMP_HIDE_NUL,
 561 };
 562
 563 static int cmp_bss(struct cfg80211_bss *a,
 564                    struct cfg80211_bss *b,
 565                    enum bss_compare_mode mode)
 566 {
 567         const struct cfg80211_bss_ies *a_ies, *b_ies;
 568         const u8 *ie1 = NULL;
 569         const u8 *ie2 = NULL;
 570         int i, r;
 571
 572         if (a->channel != b->channel)
 573                 return b->channel->center_freq - a->channel->center_freq;
 574
 575         a_ies = rcu_access_pointer(a->ies);
 576         if (!a_ies)
 577                 return -1;
 578         b_ies = rcu_access_pointer(b->ies);
 579         if (!b_ies)
 580                 return 1;
 581
 582         if (WLAN_CAPABILITY_IS_STA_BSS(a->capability))
 583                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 584                                        a_ies->data, a_ies->len);
 585         if (WLAN_CAPABILITY_IS_STA_BSS(b->capability))
 586                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 587                                        b_ies->data, b_ies->len);
 588         if (ie1 && ie2) {
 589                 int mesh_id_cmp;
 590
 591                 if (ie1[1] == ie2[1])
 592                         mesh_id_cmp = memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 593                 else
 594                         mesh_id_cmp = ie2[1] - ie1[1];
 595
 596                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 597                                        a_ies->data, a_ies->len);
 598                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 599                                        b_ies->data, b_ies->len);
 600                 if (ie1 && ie2) {
 601                         if (mesh_id_cmp)
 602                                 return mesh_id_cmp;
 603                         if (ie1[1] != ie2[1])
 604                                 return ie2[1] - ie1[1];
 605                         return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 606                 }
 607         }
 608
 609         r = memcmp(a->bssid, b->bssid, sizeof(a->bssid));
 610         if (r)
 611                 return r;
 612
 613         ie1 = cfg80211_find_ie(WLAN_EID_SSID, a_ies->data, a_ies->len);
 614         ie2 = cfg80211_find_ie(WLAN_EID_SSID, b_ies->data, b_ies->len);
 615
 616         if (!ie1 && !ie2)
 617                 return 0;
 618
 619         /*
 620          * Note that with "hide_ssid", the function returns a match if
 621          * the already-present BSS ("b") is a hidden SSID beacon for
 622          * the new BSS ("a").
 623          */
 624
 625         /* sort missing IE before (left of) present IE */
 626         if (!ie1)
 627                 return -1;
 628         if (!ie2)
 629                 return 1;
 630
 631         switch (mode) {
 632         case BSS_CMP_HIDE_ZLEN:
 633                 /*
 634                  * In ZLEN mode we assume the BSS entry we're
 635                  * looking for has a zero-length SSID. So if
 636                  * the one we're looking at right now has that,
 637                  * return 0. Otherwise, return the difference
 638                  * in length, but since we're looking for the
 639                  * 0-length it's really equivalent to returning
 640                  * the length of the one we're looking at.
 641                  *
 642                  * No content comparison is needed as we assume
 643                  * the content length is zero.
 644                  */
 645                 return ie2[1];
 646         case BSS_CMP_REGULAR:
 647         default:
 648                 /* sort by length first, then by contents */
 649                 if (ie1[1] != ie2[1])
 650                         return ie2[1] - ie1[1];
 651                 return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 652         case BSS_CMP_HIDE_NUL:
 653                 if (ie1[1] != ie2[1])
 654                         return ie2[1] - ie1[1];
 655                 /* this is equivalent to memcmp(zeroes, ie2 + 2, len) */
 656                 for (i = 0; i < ie2[1]; i++)
 657                         if (ie2[i + 2])
 658                                 return -1;
 659                 return 0;
 660         }
 661 }
 662
 663 static bool cfg80211_bss_type_match(u16 capability,
 664                                     enum nl80211_band band,
 665                                     enum ieee80211_bss_type bss_type)
 666 {
 667         bool ret = true;
 668         u16 mask, val;
 669
 670         if (bss_type == IEEE80211_BSS_TYPE_ANY)
 671                 return ret;
 672
 673         if (band == NL80211_BAND_60GHZ) {
 674                 mask = WLAN_CAPABILITY_DMG_TYPE_MASK;
 675                 switch (bss_type) {
 676                 case IEEE80211_BSS_TYPE_ESS:
 677                         val = WLAN_CAPABILITY_DMG_TYPE_AP;
 678                         break;
 679                 case IEEE80211_BSS_TYPE_PBSS:
 680                         val = WLAN_CAPABILITY_DMG_TYPE_PBSS;
 681                         break;
 682                 case IEEE80211_BSS_TYPE_IBSS:
 683                         val = WLAN_CAPABILITY_DMG_TYPE_IBSS;
 684                         break;
 685                 default:
 686                         return false;
 687                 }
 688         } else {
 689                 mask = WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS;
 690                 switch (bss_type) {
 691                 case IEEE80211_BSS_TYPE_ESS:
 692                         val = WLAN_CAPABILITY_ESS;
 693                         break;
 694                 case IEEE80211_BSS_TYPE_IBSS:
 695                         val = WLAN_CAPABILITY_IBSS;
 696                         break;
 697                 case IEEE80211_BSS_TYPE_MBSS:
 698                         val = 0;
 699                         break;
 700                 default:
 701                         return false;
 702                 }
 703         }
 704
 705         ret = ((capability & mask) == val);
 706         return ret;
 707 }
 708
 709 /* Returned bss is reference counted and must be cleaned up appropriately. */
 710 struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
 711                                       struct ieee80211_channel *channel,
 712                                       const u8 *bssid,
 713                                       const u8 *ssid, size_t ssid_len,
 714                                       enum ieee80211_bss_type bss_type,
 715                                       enum ieee80211_privacy privacy)
 716 {
 717         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 718         struct cfg80211_internal_bss *bss, *res = NULL;
 719         unsigned long now = jiffies;
 720         int bss_privacy;
 721
 722         trace_cfg80211_get_bss(wiphy, channel, bssid, ssid, ssid_len, bss_type,
 723                                privacy);
 724
 725         spin_lock_bh(&rdev->bss_lock);
 726
 727         list_for_each_entry(bss, &rdev->bss_list, list) {
 728                 if (!cfg80211_bss_type_match(bss->pub.capability,
 729                                              bss->pub.channel->band, bss_type))
 730                         continue;
 731
 732                 bss_privacy = (bss->pub.capability & WLAN_CAPABILITY_PRIVACY);
 733                 if ((privacy == IEEE80211_PRIVACY_ON && !bss_privacy) ||
 734                     (privacy == IEEE80211_PRIVACY_OFF && bss_privacy))
 735                         continue;
 736                 if (channel && bss->pub.channel != channel)
 737                         continue;
 738                 if (!is_valid_ether_addr(bss->pub.bssid))
 739                         continue;
 740                 /* Don't get expired BSS structs */
 741                 if (time_after(now, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE) &&
 742                     !atomic_read(&bss->hold))
 743                         continue;
 744                 if (is_bss(&bss->pub, bssid, ssid, ssid_len)) {
 745                         res = bss;
 746                         bss_ref_get(rdev, res);
 747                         break;
 748                 }
 749         }
 750
 751         spin_unlock_bh(&rdev->bss_lock);
 752         if (!res)
 753                 return NULL;
 754         trace_cfg80211_return_bss(&res->pub);
 755         return &res->pub;
 756 }
 757 EXPORT_SYMBOL(cfg80211_get_bss);
 758
 759 static void rb_insert_bss(struct cfg80211_registered_device *rdev,
 760                           struct cfg80211_internal_bss *bss)
 761 {
 762         struct rb_node **p = &rdev->bss_tree.rb_node;
 763         struct rb_node *parent = NULL;
 764         struct cfg80211_internal_bss *tbss;
 765         int cmp;
 766
 767         while (*p) {
 768                 parent = *p;
 769                 tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);
 770
 771                 cmp = cmp_bss(&bss->pub, &tbss->pub, BSS_CMP_REGULAR);
 772
 773                 if (WARN_ON(!cmp)) {
 774                         /* will sort of leak this BSS */
 775                         return;
 776                 }
 777
 778                 if (cmp < 0)
 779                         p = &(*p)->rb_left;
 780                 else
 781                         p = &(*p)->rb_right;
 782         }
 783
 784         rb_link_node(&bss->rbn, parent, p);
 785         rb_insert_color(&bss->rbn, &rdev->bss_tree);
 786 }
 787
 788 static struct cfg80211_internal_bss *
 789 rb_find_bss(struct cfg80211_registered_device *rdev,
 790             struct cfg80211_internal_bss *res,
 791             enum bss_compare_mode mode)
 792 {
 793         struct rb_node *n = rdev->bss_tree.rb_node;
 794         struct cfg80211_internal_bss *bss;
 795         int r;
 796
 797         while (n) {
 798                 bss = rb_entry(n, struct cfg80211_internal_bss, rbn);
 799                 r = cmp_bss(&res->pub, &bss->pub, mode);
 800
 801                 if (r == 0)
 802                         return bss;
 803                 else if (r < 0)
 804                         n = n->rb_left;
 805                 else
 806                         n = n->rb_right;
 807         }
 808
 809         return NULL;
 810 }
 811
 812 static bool cfg80211_combine_bsses(struct cfg80211_registered_device *rdev,
 813                                    struct cfg80211_internal_bss *new)
 814 {
 815         const struct cfg80211_bss_ies *ies;
 816         struct cfg80211_internal_bss *bss;
 817         const u8 *ie;
 818         int i, ssidlen;
 819         u8 fold = 0;
 820         u32 n_entries = 0;
 821
 822         ies = rcu_access_pointer(new->pub.beacon_ies);
 823         if (WARN_ON(!ies))
 824                 return false;
 825
 826         ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 827         if (!ie) {
 828                 /* nothing to do */
 829                 return true;
 830         }
 831
 832         ssidlen = ie[1];
 833         for (i = 0; i < ssidlen; i++)
 834                 fold |= ie[2 + i];
 835
 836         if (fold) {
 837                 /* not a hidden SSID */
 838                 return true;
 839         }
 840
 841         /* This is the bad part ... */
 842
 843         list_for_each_entry(bss, &rdev->bss_list, list) {
 844                 /*
 845                  * we're iterating all the entries anyway, so take the
 846                  * opportunity to validate the list length accounting
 847                  */
 848                 n_entries++;
 849
 850                 if (!ether_addr_equal(bss->pub.bssid, new->pub.bssid))
 851                         continue;
 852                 if (bss->pub.channel != new->pub.channel)
 853                         continue;
 854                 if (bss->pub.scan_width != new->pub.scan_width)
 855                         continue;
 856                 if (rcu_access_pointer(bss->pub.beacon_ies))
 857                         continue;
 858                 ies = rcu_access_pointer(bss->pub.ies);
 859                 if (!ies)
 860                         continue;
 861                 ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 862                 if (!ie)
 863                         continue;
 864                 if (ssidlen && ie[1] != ssidlen)
 865                         continue;
 866                 if (WARN_ON_ONCE(bss->pub.hidden_beacon_bss))
 867                         continue;
 868                 if (WARN_ON_ONCE(!list_empty(&bss->hidden_list)))
 869                         list_del(&bss->hidden_list);
 870                 /* combine them */
 871                 list_add(&bss->hidden_list, &new->hidden_list);
 872                 bss->pub.hidden_beacon_bss = &new->pub;
 873                 new->refcount += bss->refcount;
 874                 rcu_assign_pointer(bss->pub.beacon_ies,
 875                                    new->pub.beacon_ies);
 876         }
 877
 878         WARN_ONCE(n_entries != rdev->bss_entries,
 879                   "rdev bss entries[%d]/list[len:%d] corruption\n",
 880                   rdev->bss_entries, n_entries);
 881
 882         return true;
 883 }
 884
 885 /* Returned bss is reference counted and must be cleaned up appropriately. */
 886 static struct cfg80211_internal_bss *
 887 cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 888                     struct cfg80211_internal_bss *tmp,
 889                     bool signal_valid)
 890 {
 891         struct cfg80211_internal_bss *found = NULL;
 892
 893         if (WARN_ON(!tmp->pub.channel))
 894                 return NULL;
 895
 896         tmp->ts = jiffies;
 897
 898         spin_lock_bh(&rdev->bss_lock);
 899
 900         if (WARN_ON(!rcu_access_pointer(tmp->pub.ies))) {
 901                 spin_unlock_bh(&rdev->bss_lock);
 902                 return NULL;
 903         }
 904
 905         found = rb_find_bss(rdev, tmp, BSS_CMP_REGULAR);
 906
 907         if (found) {
 908                 /* Update IEs */
 909                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
 910                         const struct cfg80211_bss_ies *old;
 911
 912                         old = rcu_access_pointer(found->pub.proberesp_ies);
 913
 914                         rcu_assign_pointer(found->pub.proberesp_ies,
 915                                            tmp->pub.proberesp_ies);
 916                         /* Override possible earlier Beacon frame IEs */
 917                         rcu_assign_pointer(found->pub.ies,
 918                                            tmp->pub.proberesp_ies);
 919                         if (old)
 920                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 921                                           rcu_head);
 922                 } else if (rcu_access_pointer(tmp->pub.beacon_ies)) {
 923                         const struct cfg80211_bss_ies *old;
 924                         struct cfg80211_internal_bss *bss;
 925
 926                         if (found->pub.hidden_beacon_bss &&
 927                             !list_empty(&found->hidden_list)) {
 928                                 const struct cfg80211_bss_ies *f;
 929
 930                                 /*
 931                                  * The found BSS struct is one of the probe
 932                                  * response members of a group, but we're
 933                                  * receiving a beacon (beacon_ies in the tmp
 934                                  * bss is used). This can only mean that the
 935                                  * AP changed its beacon from not having an
 936                                  * SSID to showing it, which is confusing so
 937                                  * drop this information.
 938                                  */
 939
 940                                 f = rcu_access_pointer(tmp->pub.beacon_ies);
 941                                 kfree_rcu((struct cfg80211_bss_ies *)f,
 942                                           rcu_head);
 943                                 goto drop;
 944                         }
 945
 946                         old = rcu_access_pointer(found->pub.beacon_ies);
 947
 948                         rcu_assign_pointer(found->pub.beacon_ies,
 949                                            tmp->pub.beacon_ies);
 950
 951                         /* Override IEs if they were from a beacon before */
 952                         if (old == rcu_access_pointer(found->pub.ies))
 953                                 rcu_assign_pointer(found->pub.ies,
 954                                                    tmp->pub.beacon_ies);
 955
 956                         /* Assign beacon IEs to all sub entries */
 957                         list_for_each_entry(bss, &found->hidden_list,
 958                                             hidden_list) {
 959                                 const struct cfg80211_bss_ies *ies;
 960
 961                                 ies = rcu_access_pointer(bss->pub.beacon_ies);
 962                                 WARN_ON(ies != old);
 963
 964                                 rcu_assign_pointer(bss->pub.beacon_ies,
 965                                                    tmp->pub.beacon_ies);
 966                         }
 967
 968                         if (old)
 969                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 970                                           rcu_head);
 971                 }
 972
 973                 found->pub.beacon_interval = tmp->pub.beacon_interval;
 974                 /*
 975                  * don't update the signal if beacon was heard on
 976                  * adjacent channel.
 977                  */
 978                 if (signal_valid)
 979                         found->pub.signal = tmp->pub.signal;
 980                 found->pub.capability = tmp->pub.capability;
 981                 found->ts = tmp->ts;
 982                 found->ts_boottime = tmp->ts_boottime;
 983                 found->parent_tsf = tmp->parent_tsf;
 984                 found->pub.chains = tmp->pub.chains;
 985                 memcpy(found->pub.chain_signal, tmp->pub.chain_signal,
 986                        IEEE80211_MAX_CHAINS);
 987                 ether_addr_copy(found->parent_bssid, tmp->parent_bssid);
 988         } else {
 989                 struct cfg80211_internal_bss *new;
 990                 struct cfg80211_internal_bss *hidden;
 991                 struct cfg80211_bss_ies *ies;
 992
 993                 /*
 994                  * create a copy -- the "res" variable that is passed in
 995                  * is allocated on the stack since it's not needed in the
 996                  * more common case of an update
 997                  */
 998                 new = kzalloc(sizeof(*new) + rdev->wiphy.bss_priv_size,
 999                               GFP_ATOMIC);
1000                 if (!new) {
1001                         ies = (void *)rcu_dereference(tmp->pub.beacon_ies);
1002                         if (ies)
1003                                 kfree_rcu(ies, rcu_head);
1004                         ies = (void *)rcu_dereference(tmp->pub.proberesp_ies);
1005                         if (ies)
1006                                 kfree_rcu(ies, rcu_head);
1007                         goto drop;
1008                 }
1009                 memcpy(new, tmp, sizeof(*new));
1010                 new->refcount = 1;
1011                 INIT_LIST_HEAD(&new->hidden_list);
1012
1013                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
1014                         hidden = rb_find_bss(rdev, tmp, BSS_CMP_HIDE_ZLEN);
1015                         if (!hidden)
1016                                 hidden = rb_find_bss(rdev, tmp,
1017                                                      BSS_CMP_HIDE_NUL);
1018                         if (hidden) {
1019                                 new->pub.hidden_beacon_bss = &hidden->pub;
1020                                 list_add(&new->hidden_list,
1021                                          &hidden->hidden_list);
1022                                 hidden->refcount++;
1023                                 rcu_assign_pointer(new->pub.beacon_ies,
1024                                                    hidden->pub.beacon_ies);
1025                         }
1026                 } else {
1027                         /*
1028                          * Ok so we found a beacon, and don't have an entry. If
1029                          * it's a beacon with hidden SSID, we might be in for an
1030                          * expensive search for any probe responses that should
1031                          * be grouped with this beacon for updates ...
1032                          */
1033                         if (!cfg80211_combine_bsses(rdev, new)) {
1034                                 kfree(new);
1035                                 goto drop;
1036                         }
1037                 }
1038
1039                 if (rdev->bss_entries >= bss_entries_limit &&
1040                     !cfg80211_bss_expire_oldest(rdev)) {
1041                         kfree(new);
1042                         goto drop;
1043                 }
1044
1045                 list_add_tail(&new->list, &rdev->bss_list);
1046                 rdev->bss_entries++;
1047                 rb_insert_bss(rdev, new);
1048                 found = new;
1049         }
1050
1051         rdev->bss_generation++;
1052         bss_ref_get(rdev, found);
1053         spin_unlock_bh(&rdev->bss_lock);
1054
1055         return found;
1056  drop:
1057         spin_unlock_bh(&rdev->bss_lock);
1058         return NULL;
1059 }
1060
1061 static struct ieee80211_channel *
1062 cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
1063                          struct ieee80211_channel *channel)
1064 {
1065         const u8 *tmp;
1066         u32 freq;
1067         int channel_number = -1;
1068
1069         tmp = cfg80211_find_ie(WLAN_EID_DS_PARAMS, ie, ielen);
1070         if (tmp && tmp[1] == 1) {
1071                 channel_number = tmp[2];
1072         } else {
1073                 tmp = cfg80211_find_ie(WLAN_EID_HT_OPERATION, ie, ielen);
1074                 if (tmp && tmp[1] >= sizeof(struct ieee80211_ht_operation)) {
1075                         struct ieee80211_ht_operation *htop = (void *)(tmp + 2);
1076
1077                         channel_number = htop->primary_chan;
1078                 }
1079         }
1080
1081         if (channel_number < 0)
1082                 return channel;
1083
1084         freq = ieee80211_channel_to_frequency(channel_number, channel->band);
1085         channel = ieee80211_get_channel(wiphy, freq);
1086         if (!channel)
1087                 return NULL;
1088         if (channel->flags & IEEE80211_CHAN_DISABLED)
1089                 return NULL;
1090         return channel;
1091 }
1092
1093 /* Returned bss is reference counted and must be cleaned up appropriately. */
1094 struct cfg80211_bss *
1095 cfg80211_inform_bss_data(struct wiphy *wiphy,
1096                          struct cfg80211_inform_bss *data,
1097                          enum cfg80211_bss_frame_type ftype,
1098                          const u8 *bssid, u64 tsf, u16 capability,
1099                          u16 beacon_interval, const u8 *ie, size_t ielen,
1100                          gfp_t gfp)
1101 {
1102         struct cfg80211_bss_ies *ies;
1103         struct ieee80211_channel *channel;
1104         struct cfg80211_internal_bss tmp = {}, *res;
1105         int bss_type;
1106         bool signal_valid;
1107
1108         if (WARN_ON(!wiphy))
1109                 return NULL;
1110
1111         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
1112                     (data->signal < 0 || data->signal > 100)))
1113                 return NULL;
1114
1115         channel = cfg80211_get_bss_channel(wiphy, ie, ielen, data->chan);
1116         if (!channel)
1117                 return NULL;
1118
1119         memcpy(tmp.pub.bssid, bssid, ETH_ALEN);
1120         tmp.pub.channel = channel;
1121         tmp.pub.scan_width = data->scan_width;
1122         tmp.pub.signal = data->signal;
1123         tmp.pub.beacon_interval = beacon_interval;
1124         tmp.pub.capability = capability;
1125         tmp.ts_boottime = data->boottime_ns;
1126
1127         /*
1128          * If we do not know here whether the IEs are from a Beacon or Probe
1129          * Response frame, we need to pick one of the options and only use it
1130          * with the driver that does not provide the full Beacon/Probe Response
1131          * frame. Use Beacon frame pointer to avoid indicating that this should
1132          * override the IEs pointer should we have received an earlier
1133          * indication of Probe Response data.
1134          */
1135         ies = kzalloc(sizeof(*ies) + ielen, gfp);
1136         if (!ies)
1137                 return NULL;
1138         ies->len = ielen;
1139         ies->tsf = tsf;
1140         ies->from_beacon = false;
1141         memcpy(ies->data, ie, ielen);
1142
1143         switch (ftype) {
1144         case CFG80211_BSS_FTYPE_BEACON:
1145                 ies->from_beacon = true;
1146                 /* fall through to assign */
1147         case CFG80211_BSS_FTYPE_UNKNOWN:
1148                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1149                 break;
1150         case CFG80211_BSS_FTYPE_PRESP:
1151                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1152                 break;
1153         }
1154         rcu_assign_pointer(tmp.pub.ies, ies);
1155
1156         signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
1157                 wiphy->max_adj_channel_rssi_comp;
1158         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1159         if (!res)
1160                 return NULL;
1161
1162         if (channel->band == NL80211_BAND_60GHZ) {
1163                 bss_type = res->pub.capability & WLAN_CAPABILITY_DMG_TYPE_MASK;
1164                 if (bss_type == WLAN_CAPABILITY_DMG_TYPE_AP ||
1165                     bss_type == WLAN_CAPABILITY_DMG_TYPE_PBSS)
1166                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1167         } else {
1168                 if (res->pub.capability & WLAN_CAPABILITY_ESS)
1169                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1170         }
1171
1172         trace_cfg80211_return_bss(&res->pub);
1173         /* cfg80211_bss_update gives us a referenced result */
1174         return &res->pub;
1175 }
1176 EXPORT_SYMBOL(cfg80211_inform_bss_data);
1177
1178 /* cfg80211_inform_bss_width_frame helper */
1179 struct cfg80211_bss *
1180 cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
1181                                struct cfg80211_inform_bss *data,
1182                                struct ieee80211_mgmt *mgmt, size_t len,
1183                                gfp_t gfp)
1184
1185 {
1186         struct cfg80211_internal_bss tmp = {}, *res;
1187         struct cfg80211_bss_ies *ies;
1188         struct ieee80211_channel *channel;
1189         bool signal_valid;
1190         size_t ielen = len - offsetof(struct ieee80211_mgmt,
1191                                       u.probe_resp.variable);
1192         int bss_type;
1193
1194         BUILD_BUG_ON(offsetof(struct ieee80211_mgmt, u.probe_resp.variable) !=
1195                         offsetof(struct ieee80211_mgmt, u.beacon.variable));
1196
1197         trace_cfg80211_inform_bss_frame(wiphy, data, mgmt, len);
1198
1199         if (WARN_ON(!mgmt))
1200                 return NULL;
1201
1202         if (WARN_ON(!wiphy))
1203                 return NULL;
1204
1205         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
1206                     (data->signal < 0 || data->signal > 100)))
1207                 return NULL;
1208
1209         if (WARN_ON(len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
1210                 return NULL;
1211
1212         channel = cfg80211_get_bss_channel(wiphy, mgmt->u.beacon.variable,
1213                                            ielen, data->chan);
1214         if (!channel)
1215                 return NULL;
1216
1217         ies = kzalloc(sizeof(*ies) + ielen, gfp);
1218         if (!ies)
1219                 return NULL;
1220         ies->len = ielen;
1221         ies->tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
1222         ies->from_beacon = ieee80211_is_beacon(mgmt->frame_control);
1223         memcpy(ies->data, mgmt->u.probe_resp.variable, ielen);
1224
1225         if (ieee80211_is_probe_resp(mgmt->frame_control))
1226                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1227         else
1228                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1229         rcu_assign_pointer(tmp.pub.ies, ies);
1230
1231         memcpy(tmp.pub.bssid, mgmt->bssid, ETH_ALEN);
1232         tmp.pub.channel = channel;
1233         tmp.pub.scan_width = data->scan_width;
1234         tmp.pub.signal = data->signal;
1235         tmp.pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
1236         tmp.pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
1237         tmp.ts_boottime = data->boottime_ns;
1238         tmp.parent_tsf = data->parent_tsf;
1239         tmp.pub.chains = data->chains;
1240         memcpy(tmp.pub.chain_signal, data->chain_signal, IEEE80211_MAX_CHAINS);
1241         ether_addr_copy(tmp.parent_bssid, data->parent_bssid);
1242
1243         signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
1244                 wiphy->max_adj_channel_rssi_comp;
1245         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1246         if (!res)
1247                 return NULL;
1248
1249         if (channel->band == NL80211_BAND_60GHZ) {
1250                 bss_type = res->pub.capability & WLAN_CAPABILITY_DMG_TYPE_MASK;
1251                 if (bss_type == WLAN_CAPABILITY_DMG_TYPE_AP ||
1252                     bss_type == WLAN_CAPABILITY_DMG_TYPE_PBSS)
1253                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1254         } else {
1255                 if (res->pub.capability & WLAN_CAPABILITY_ESS)
1256                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1257         }
1258
1259         trace_cfg80211_return_bss(&res->pub);
1260         /* cfg80211_bss_update gives us a referenced result */
1261         return &res->pub;
1262 }
1263 EXPORT_SYMBOL(cfg80211_inform_bss_frame_data);
1264
1265 void cfg80211_ref_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1266 {
1267         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1268         struct cfg80211_internal_bss *bss;
1269
1270         if (!pub)
1271                 return;
1272
1273         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1274
1275         spin_lock_bh(&rdev->bss_lock);
1276         bss_ref_get(rdev, bss);
1277         spin_unlock_bh(&rdev->bss_lock);
1278 }
1279 EXPORT_SYMBOL(cfg80211_ref_bss);
1280
1281 void cfg80211_put_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1282 {
1283         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1284         struct cfg80211_internal_bss *bss;
1285
1286         if (!pub)
1287                 return;
1288
1289         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1290
1291         spin_lock_bh(&rdev->bss_lock);
1292         bss_ref_put(rdev, bss);
1293         spin_unlock_bh(&rdev->bss_lock);
1294 }
1295 EXPORT_SYMBOL(cfg80211_put_bss);
1296
1297 void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1298 {
1299         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1300         struct cfg80211_internal_bss *bss;
1301
1302         if (WARN_ON(!pub))
1303                 return;
1304
1305         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1306
1307         spin_lock_bh(&rdev->bss_lock);
1308         if (!list_empty(&bss->list)) {
1309                 if (__cfg80211_unlink_bss(rdev, bss))
1310                         rdev->bss_generation++;
1311         }
1312         spin_unlock_bh(&rdev->bss_lock);
1313 }
1314 EXPORT_SYMBOL(cfg80211_unlink_bss);
1315
1316 #ifdef CONFIG_CFG80211_WEXT
1317 static struct cfg80211_registered_device *
1318 cfg80211_get_dev_from_ifindex(struct net *net, int ifindex)
1319 {
1320         struct cfg80211_registered_device *rdev;
1321         struct net_device *dev;
1322
1323         ASSERT_RTNL();
1324
1325         dev = dev_get_by_index(net, ifindex);
1326         if (!dev)
1327                 return ERR_PTR(-ENODEV);
1328         if (dev->ieee80211_ptr)
1329                 rdev = wiphy_to_rdev(dev->ieee80211_ptr->wiphy);
1330         else
1331                 rdev = ERR_PTR(-ENODEV);
1332         dev_put(dev);
1333         return rdev;
1334 }
1335
1336 int cfg80211_wext_siwscan(struct net_device *dev,
1337                           struct iw_request_info *info,
1338                           union iwreq_data *wrqu, char *extra)
1339 {
1340         struct cfg80211_registered_device *rdev;
1341         struct wiphy *wiphy;
1342         struct iw_scan_req *wreq = NULL;
1343         struct cfg80211_scan_request *creq = NULL;
1344         int i, err, n_channels = 0;
1345         enum nl80211_band band;
1346
1347         if (!netif_running(dev))
1348                 return -ENETDOWN;
1349
1350         if (wrqu->data.length == sizeof(struct iw_scan_req))
1351                 wreq = (struct iw_scan_req *)extra;
1352
1353         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1354
1355         if (IS_ERR(rdev))
1356                 return PTR_ERR(rdev);
1357
1358         if (rdev->scan_req || rdev->scan_msg) {
1359                 err = -EBUSY;
1360                 goto out;
1361         }
1362
1363         wiphy = &rdev->wiphy;
1364
1365         /* Determine number of channels, needed to allocate creq */
1366         if (wreq && wreq->num_channels)
1367                 n_channels = wreq->num_channels;
1368         else
1369                 n_channels = ieee80211_get_num_supported_channels(wiphy);
1370
1371         creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
1372                        n_channels * sizeof(void *),
1373                        GFP_ATOMIC);
1374         if (!creq) {
1375                 err = -ENOMEM;
1376                 goto out;
1377         }
1378
1379         creq->wiphy = wiphy;
1380         creq->wdev = dev->ieee80211_ptr;
1381         /* SSIDs come after channels */
1382         creq->ssids = (void *)&creq->channels[n_channels];
1383         creq->n_channels = n_channels;
1384         creq->n_ssids = 1;
1385         creq->scan_start = jiffies;
1386
1387         /* translate "Scan on frequencies" request */
1388         i = 0;
1389         for (band = 0; band < NUM_NL80211_BANDS; band++) {
1390                 int j;
1391
1392                 if (!wiphy->bands[band])
1393                         continue;
1394
1395                 for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
1396                         /* ignore disabled channels */
1397                         if (wiphy->bands[band]->channels[j].flags &
1398                                                 IEEE80211_CHAN_DISABLED)
1399                                 continue;
1400
1401                         /* If we have a wireless request structure and the
1402                          * wireless request specifies frequencies, then search
1403                          * for the matching hardware channel.
1404                          */
1405                         if (wreq && wreq->num_channels) {
1406                                 int k;
1407                                 int wiphy_freq = wiphy->bands[band]->channels[j].center_freq;
1408                                 for (k = 0; k < wreq->num_channels; k++) {
1409                                         struct iw_freq *freq =
1410                                                 &wreq->channel_list[k];
1411                                         int wext_freq =
1412                                                 cfg80211_wext_freq(freq);
1413
1414                                         if (wext_freq == wiphy_freq)
1415                                                 goto wext_freq_found;
1416                                 }
1417                                 goto wext_freq_not_found;
1418                         }
1419
1420                 wext_freq_found:
1421                         creq->channels[i] = &wiphy->bands[band]->channels[j];
1422                         i++;
1423                 wext_freq_not_found: ;
1424                 }
1425         }
1426         /* No channels found? */
1427         if (!i) {
1428                 err = -EINVAL;
1429                 goto out;
1430         }
1431
1432         /* Set real number of channels specified in creq->channels[] */
1433         creq->n_channels = i;
1434
1435         /* translate "Scan for SSID" request */
1436         if (wreq) {
1437                 if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
1438                         if (wreq->essid_len > IEEE80211_MAX_SSID_LEN) {
1439                                 err = -EINVAL;
1440                                 goto out;
1441                         }
1442                         memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
1443                         creq->ssids[0].ssid_len = wreq->essid_len;
1444                 }
1445                 if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE)
1446                         creq->n_ssids = 0;
1447         }
1448
1449         for (i = 0; i < NUM_NL80211_BANDS; i++)
1450                 if (wiphy->bands[i])
1451                         creq->rates[i] = (1 << wiphy->bands[i]->n_bitrates) - 1;
1452
1453         eth_broadcast_addr(creq->bssid);
1454
1455         rdev->scan_req = creq;
1456         err = rdev_scan(rdev, creq);
1457         if (err) {
1458                 rdev->scan_req = NULL;
1459                 /* creq will be freed below */
1460         } else {
1461                 nl80211_send_scan_start(rdev, dev->ieee80211_ptr);
1462                 /* creq now owned by driver */
1463                 creq = NULL;
1464                 dev_hold(dev);
1465         }
1466  out:
1467         kfree(creq);
1468         return err;
1469 }
1470 EXPORT_WEXT_HANDLER(cfg80211_wext_siwscan);
1471
1472 static char *ieee80211_scan_add_ies(struct iw_request_info *info,
1473                                     const struct cfg80211_bss_ies *ies,
1474                                     char *current_ev, char *end_buf)
1475 {
1476         const u8 *pos, *end, *next;
1477         struct iw_event iwe;
1478
1479         if (!ies)
1480                 return current_ev;
1481
1482         /*
1483          * If needed, fragment the IEs buffer (at IE boundaries) into short
1484          * enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
1485          */
1486         pos = ies->data;
1487         end = pos + ies->len;
1488
1489         while (end - pos > IW_GENERIC_IE_MAX) {
1490                 next = pos + 2 + pos[1];
1491                 while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
1492                         next = next + 2 + next[1];
1493
1494                 memset(&iwe, 0, sizeof(iwe));
1495                 iwe.cmd = IWEVGENIE;
1496                 iwe.u.data.length = next - pos;
1497                 current_ev = iwe_stream_add_point_check(info, current_ev,
1498                                                         end_buf, &iwe,
1499                                                         (void *)pos);
1500                 if (IS_ERR(current_ev))
1501                         return current_ev;
1502                 pos = next;
1503         }
1504
1505         if (end > pos) {
1506                 memset(&iwe, 0, sizeof(iwe));
1507                 iwe.cmd = IWEVGENIE;
1508                 iwe.u.data.length = end - pos;
1509                 current_ev = iwe_stream_add_point_check(info, current_ev,
1510                                                         end_buf, &iwe,
1511                                                         (void *)pos);
1512                 if (IS_ERR(current_ev))
1513                         return current_ev;
1514         }
1515
1516         return current_ev;
1517 }
1518
1519 static char *
1520 ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,
1521               struct cfg80211_internal_bss *bss, char *current_ev,
1522               char *end_buf)
1523 {
1524         const struct cfg80211_bss_ies *ies;
1525         struct iw_event iwe;
1526         const u8 *ie;
1527         u8 buf[50];
1528         u8 *cfg, *p, *tmp;
1529         int rem, i, sig;
1530         bool ismesh = false;
1531
1532         memset(&iwe, 0, sizeof(iwe));
1533         iwe.cmd = SIOCGIWAP;
1534         iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
1535         memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN);
1536         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1537                                                 IW_EV_ADDR_LEN);
1538         if (IS_ERR(current_ev))
1539                 return current_ev;
1540
1541         memset(&iwe, 0, sizeof(iwe));
1542         iwe.cmd = SIOCGIWFREQ;
1543         iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq);
1544         iwe.u.freq.e = 0;
1545         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1546                                                 IW_EV_FREQ_LEN);
1547         if (IS_ERR(current_ev))
1548                 return current_ev;
1549
1550         memset(&iwe, 0, sizeof(iwe));
1551         iwe.cmd = SIOCGIWFREQ;
1552         iwe.u.freq.m = bss->pub.channel->center_freq;
1553         iwe.u.freq.e = 6;
1554         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1555                                                 IW_EV_FREQ_LEN);
1556         if (IS_ERR(current_ev))
1557                 return current_ev;
1558
1559         if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) {
1560                 memset(&iwe, 0, sizeof(iwe));
1561                 iwe.cmd = IWEVQUAL;
1562                 iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED |
1563                                      IW_QUAL_NOISE_INVALID |
1564                                      IW_QUAL_QUAL_UPDATED;
1565                 switch (wiphy->signal_type) {
1566                 case CFG80211_SIGNAL_TYPE_MBM:
1567                         sig = bss->pub.signal / 100;
1568                         iwe.u.qual.level = sig;
1569                         iwe.u.qual.updated |= IW_QUAL_DBM;
1570                         if (sig < -110)         /* rather bad */
1571                                 sig = -110;
1572                         else if (sig > -40)     /* perfect */
1573                                 sig = -40;
1574                         /* will give a range of 0 .. 70 */
1575                         iwe.u.qual.qual = sig + 110;
1576                         break;
1577                 case CFG80211_SIGNAL_TYPE_UNSPEC:
1578                         iwe.u.qual.level = bss->pub.signal;
1579                         /* will give range 0 .. 100 */
1580                         iwe.u.qual.qual = bss->pub.signal;
1581                         break;
1582                 default:
1583                         /* not reached */
1584                         break;
1585                 }
1586                 current_ev = iwe_stream_add_event_check(info, current_ev,
1587                                                         end_buf, &iwe,
1588                                                         IW_EV_QUAL_LEN);
1589                 if (IS_ERR(current_ev))
1590                         return current_ev;
1591         }
1592
1593         memset(&iwe, 0, sizeof(iwe));
1594         iwe.cmd = SIOCGIWENCODE;
1595         if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY)
1596                 iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
1597         else
1598                 iwe.u.data.flags = IW_ENCODE_DISABLED;
1599         iwe.u.data.length = 0;
1600         current_ev = iwe_stream_add_point_check(info, current_ev, end_buf,
1601                                                 &iwe, "");
1602         if (IS_ERR(current_ev))
1603                 return current_ev;
1604
1605         rcu_read_lock();
1606         ies = rcu_dereference(bss->pub.ies);
1607         rem = ies->len;
1608         ie = ies->data;
1609
1610         while (rem >= 2) {
1611                 /* invalid data */
1612                 if (ie[1] > rem - 2)
1613                         break;
1614
1615                 switch (ie[0]) {
1616                 case WLAN_EID_SSID:
1617                         memset(&iwe, 0, sizeof(iwe));
1618                         iwe.cmd = SIOCGIWESSID;
1619                         iwe.u.data.length = ie[1];
1620                         iwe.u.data.flags = 1;
1621                         current_ev = iwe_stream_add_point_check(info,
1622                                                                 current_ev,
1623                                                                 end_buf, &iwe,
1624                                                                 (u8 *)ie + 2);
1625                         if (IS_ERR(current_ev))
1626                                 goto unlock;
1627                         break;
1628                 case WLAN_EID_MESH_ID:
1629                         memset(&iwe, 0, sizeof(iwe));
1630                         iwe.cmd = SIOCGIWESSID;
1631                         iwe.u.data.length = ie[1];
1632                         iwe.u.data.flags = 1;
1633                         current_ev = iwe_stream_add_point_check(info,
1634                                                                 current_ev,
1635                                                                 end_buf, &iwe,
1636                                                                 (u8 *)ie + 2);
1637                         if (IS_ERR(current_ev))
1638                                 goto unlock;
1639                         break;
1640                 case WLAN_EID_MESH_CONFIG:
1641                         ismesh = true;
1642                         if (ie[1] != sizeof(struct ieee80211_meshconf_ie))
1643                                 break;
1644                         cfg = (u8 *)ie + 2;
1645                         memset(&iwe, 0, sizeof(iwe));
1646                         iwe.cmd = IWEVCUSTOM;
1647                         sprintf(buf, "Mesh Network Path Selection Protocol ID: "
1648                                 "0x%02X", cfg[0]);
1649                         iwe.u.data.length = strlen(buf);
1650                         current_ev = iwe_stream_add_point_check(info,
1651                                                                 current_ev,
1652                                                                 end_buf,
1653                                                                 &iwe, buf);
1654                         if (IS_ERR(current_ev))
1655                                 goto unlock;
1656                         sprintf(buf, "Path Selection Metric ID: 0x%02X",
1657                                 cfg[1]);
1658                         iwe.u.data.length = strlen(buf);
1659                         current_ev = iwe_stream_add_point_check(info,
1660                                                                 current_ev,
1661                                                                 end_buf,
1662                                                                 &iwe, buf);
1663                         if (IS_ERR(current_ev))
1664                                 goto unlock;
1665                         sprintf(buf, "Congestion Control Mode ID: 0x%02X",
1666                                 cfg[2]);
1667                         iwe.u.data.length = strlen(buf);
1668                         current_ev = iwe_stream_add_point_check(info,
1669                                                                 current_ev,
1670                                                                 end_buf,
1671                                                                 &iwe, buf);
1672                         if (IS_ERR(current_ev))
1673                                 goto unlock;
1674                         sprintf(buf, "Synchronization ID: 0x%02X", cfg[3]);
1675                         iwe.u.data.length = strlen(buf);
1676                         current_ev = iwe_stream_add_point_check(info,
1677                                                                 current_ev,
1678                                                                 end_buf,
1679                                                                 &iwe, buf);
1680                         if (IS_ERR(current_ev))
1681                                 goto unlock;
1682                         sprintf(buf, "Authentication ID: 0x%02X", cfg[4]);
1683                         iwe.u.data.length = strlen(buf);
1684                         current_ev = iwe_stream_add_point_check(info,
1685                                                                 current_ev,
1686                                                                 end_buf,
1687                                                                 &iwe, buf);
1688                         if (IS_ERR(current_ev))
1689                                 goto unlock;
1690                         sprintf(buf, "Formation Info: 0x%02X", cfg[5]);
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, "Capabilities: 0x%02X", cfg[6]);
1699                         iwe.u.data.length = strlen(buf);
1700                         current_ev = iwe_stream_add_point_check(info,
1701                                                                 current_ev,
1702                                                                 end_buf,
1703                                                                 &iwe, buf);
1704                         if (IS_ERR(current_ev))
1705                                 goto unlock;
1706                         break;
1707                 case WLAN_EID_SUPP_RATES:
1708                 case WLAN_EID_EXT_SUPP_RATES:
1709                         /* display all supported rates in readable format */
1710                         p = current_ev + iwe_stream_lcp_len(info);
1711
1712                         memset(&iwe, 0, sizeof(iwe));
1713                         iwe.cmd = SIOCGIWRATE;
1714                         /* Those two flags are ignored... */
1715                         iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;
1716
1717                         for (i = 0; i < ie[1]; i++) {
1718                                 iwe.u.bitrate.value =
1719                                         ((ie[i + 2] & 0x7f) * 500000);
1720                                 tmp = p;
1721                                 p = iwe_stream_add_value(info, current_ev, p,
1722                                                          end_buf, &iwe,
1723                                                          IW_EV_PARAM_LEN);
1724                                 if (p == tmp) {
1725                                         current_ev = ERR_PTR(-E2BIG);
1726                                         goto unlock;
1727                                 }
1728                         }
1729                         current_ev = p;
1730                         break;
1731                 }
1732                 rem -= ie[1] + 2;
1733                 ie += ie[1] + 2;
1734         }
1735
1736         if (bss->pub.capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS) ||
1737             ismesh) {
1738                 memset(&iwe, 0, sizeof(iwe));
1739                 iwe.cmd = SIOCGIWMODE;
1740                 if (ismesh)
1741                         iwe.u.mode = IW_MODE_MESH;
1742                 else if (bss->pub.capability & WLAN_CAPABILITY_ESS)
1743                         iwe.u.mode = IW_MODE_MASTER;
1744                 else
1745                         iwe.u.mode = IW_MODE_ADHOC;
1746                 current_ev = iwe_stream_add_event_check(info, current_ev,
1747                                                         end_buf, &iwe,
1748                                                         IW_EV_UINT_LEN);
1749                 if (IS_ERR(current_ev))
1750                         goto unlock;
1751         }
1752
1753         memset(&iwe, 0, sizeof(iwe));
1754         iwe.cmd = IWEVCUSTOM;
1755         sprintf(buf, "tsf=%016llx", (unsigned long long)(ies->tsf));
1756         iwe.u.data.length = strlen(buf);
1757         current_ev = iwe_stream_add_point_check(info, current_ev, end_buf,
1758                                                 &iwe, buf);
1759         if (IS_ERR(current_ev))
1760                 goto unlock;
1761         memset(&iwe, 0, sizeof(iwe));
1762         iwe.cmd = IWEVCUSTOM;
1763         sprintf(buf, " Last beacon: %ums ago",
1764                 elapsed_jiffies_msecs(bss->ts));
1765         iwe.u.data.length = strlen(buf);
1766         current_ev = iwe_stream_add_point_check(info, current_ev,
1767                                                 end_buf, &iwe, buf);
1768         if (IS_ERR(current_ev))
1769                 goto unlock;
1770
1771         current_ev = ieee80211_scan_add_ies(info, ies, current_ev, end_buf);
1772
1773  unlock:
1774         rcu_read_unlock();
1775         return current_ev;
1776 }
1777
1778
1779 static int ieee80211_scan_results(struct cfg80211_registered_device *rdev,
1780                                   struct iw_request_info *info,
1781                                   char *buf, size_t len)
1782 {
1783         char *current_ev = buf;
1784         char *end_buf = buf + len;
1785         struct cfg80211_internal_bss *bss;
1786         int err = 0;
1787
1788         spin_lock_bh(&rdev->bss_lock);
1789         cfg80211_bss_expire(rdev);
1790
1791         list_for_each_entry(bss, &rdev->bss_list, list) {
1792                 if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
1793                         err = -E2BIG;
1794                         break;
1795                 }
1796                 current_ev = ieee80211_bss(&rdev->wiphy, info, bss,
1797                                            current_ev, end_buf);
1798                 if (IS_ERR(current_ev)) {
1799                         err = PTR_ERR(current_ev);
1800                         break;
1801                 }
1802         }
1803         spin_unlock_bh(&rdev->bss_lock);
1804
1805         if (err)
1806                 return err;
1807         return current_ev - buf;
1808 }
1809
1810
1811 int cfg80211_wext_giwscan(struct net_device *dev,
1812                           struct iw_request_info *info,
1813                           struct iw_point *data, char *extra)
1814 {
1815         struct cfg80211_registered_device *rdev;
1816         int res;
1817
1818         if (!netif_running(dev))
1819                 return -ENETDOWN;
1820
1821         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1822
1823         if (IS_ERR(rdev))
1824                 return PTR_ERR(rdev);
1825
1826         if (rdev->scan_req || rdev->scan_msg)
1827                 return -EAGAIN;
1828
1829         res = ieee80211_scan_results(rdev, info, extra, data->length);
1830         data->length = 0;
1831         if (res >= 0) {
1832                 data->length = res;
1833                 res = 0;
1834         }
1835
1836         return res;
1837 }
1838 EXPORT_WEXT_HANDLER(cfg80211_wext_giwscan);
1839 #endif