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TOMOYO Linux Cross Reference
Linux/net/wireless/scan.c

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  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         /* 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 /*
1062  * Update RX channel information based on the available frame payload
1063  * information. This is mainly for the 2.4 GHz band where frames can be received
1064  * from neighboring channels and the Beacon frames use the DSSS Parameter Set
1065  * element to indicate the current (transmitting) channel, but this might also
1066  * be needed on other bands if RX frequency does not match with the actual
1067  * operating channel of a BSS.
1068  */
1069 static struct ieee80211_channel *
1070 cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
1071                          struct ieee80211_channel *channel,
1072                          enum nl80211_bss_scan_width scan_width)
1073 {
1074         const u8 *tmp;
1075         u32 freq;
1076         int channel_number = -1;
1077         struct ieee80211_channel *alt_channel;
1078 
1079         tmp = cfg80211_find_ie(WLAN_EID_DS_PARAMS, ie, ielen);
1080         if (tmp && tmp[1] == 1) {
1081                 channel_number = tmp[2];
1082         } else {
1083                 tmp = cfg80211_find_ie(WLAN_EID_HT_OPERATION, ie, ielen);
1084                 if (tmp && tmp[1] >= sizeof(struct ieee80211_ht_operation)) {
1085                         struct ieee80211_ht_operation *htop = (void *)(tmp + 2);
1086 
1087                         channel_number = htop->primary_chan;
1088                 }
1089         }
1090 
1091         if (channel_number < 0) {
1092                 /* No channel information in frame payload */
1093                 return channel;
1094         }
1095 
1096         freq = ieee80211_channel_to_frequency(channel_number, channel->band);
1097         alt_channel = ieee80211_get_channel(wiphy, freq);
1098         if (!alt_channel) {
1099                 if (channel->band == NL80211_BAND_2GHZ) {
1100                         /*
1101                          * Better not allow unexpected channels when that could
1102                          * be going beyond the 1-11 range (e.g., discovering
1103                          * BSS on channel 12 when radio is configured for
1104                          * channel 11.
1105                          */
1106                         return NULL;
1107                 }
1108 
1109                 /* No match for the payload channel number - ignore it */
1110                 return channel;
1111         }
1112 
1113         if (scan_width == NL80211_BSS_CHAN_WIDTH_10 ||
1114             scan_width == NL80211_BSS_CHAN_WIDTH_5) {
1115                 /*
1116                  * Ignore channel number in 5 and 10 MHz channels where there
1117                  * may not be an n:1 or 1:n mapping between frequencies and
1118                  * channel numbers.
1119                  */
1120                 return channel;
1121         }
1122 
1123         /*
1124          * Use the channel determined through the payload channel number
1125          * instead of the RX channel reported by the driver.
1126          */
1127         if (alt_channel->flags & IEEE80211_CHAN_DISABLED)
1128                 return NULL;
1129         return alt_channel;
1130 }
1131 
1132 /* Returned bss is reference counted and must be cleaned up appropriately. */
1133 struct cfg80211_bss *
1134 cfg80211_inform_bss_data(struct wiphy *wiphy,
1135                          struct cfg80211_inform_bss *data,
1136                          enum cfg80211_bss_frame_type ftype,
1137                          const u8 *bssid, u64 tsf, u16 capability,
1138                          u16 beacon_interval, const u8 *ie, size_t ielen,
1139                          gfp_t gfp)
1140 {
1141         struct cfg80211_bss_ies *ies;
1142         struct ieee80211_channel *channel;
1143         struct cfg80211_internal_bss tmp = {}, *res;
1144         int bss_type;
1145         bool signal_valid;
1146 
1147         if (WARN_ON(!wiphy))
1148                 return NULL;
1149 
1150         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
1151                     (data->signal < 0 || data->signal > 100)))
1152                 return NULL;
1153 
1154         channel = cfg80211_get_bss_channel(wiphy, ie, ielen, data->chan,
1155                                            data->scan_width);
1156         if (!channel)
1157                 return NULL;
1158 
1159         memcpy(tmp.pub.bssid, bssid, ETH_ALEN);
1160         tmp.pub.channel = channel;
1161         tmp.pub.scan_width = data->scan_width;
1162         tmp.pub.signal = data->signal;
1163         tmp.pub.beacon_interval = beacon_interval;
1164         tmp.pub.capability = capability;
1165         tmp.ts_boottime = data->boottime_ns;
1166 
1167         /*
1168          * If we do not know here whether the IEs are from a Beacon or Probe
1169          * Response frame, we need to pick one of the options and only use it
1170          * with the driver that does not provide the full Beacon/Probe Response
1171          * frame. Use Beacon frame pointer to avoid indicating that this should
1172          * override the IEs pointer should we have received an earlier
1173          * indication of Probe Response data.
1174          */
1175         ies = kzalloc(sizeof(*ies) + ielen, gfp);
1176         if (!ies)
1177                 return NULL;
1178         ies->len = ielen;
1179         ies->tsf = tsf;
1180         ies->from_beacon = false;
1181         memcpy(ies->data, ie, ielen);
1182 
1183         switch (ftype) {
1184         case CFG80211_BSS_FTYPE_BEACON:
1185                 ies->from_beacon = true;
1186                 /* fall through */
1187         case CFG80211_BSS_FTYPE_UNKNOWN:
1188                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1189                 break;
1190         case CFG80211_BSS_FTYPE_PRESP:
1191                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1192                 break;
1193         }
1194         rcu_assign_pointer(tmp.pub.ies, ies);
1195 
1196         signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
1197                 wiphy->max_adj_channel_rssi_comp;
1198         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1199         if (!res)
1200                 return NULL;
1201 
1202         if (channel->band == NL80211_BAND_60GHZ) {
1203                 bss_type = res->pub.capability & WLAN_CAPABILITY_DMG_TYPE_MASK;
1204                 if (bss_type == WLAN_CAPABILITY_DMG_TYPE_AP ||
1205                     bss_type == WLAN_CAPABILITY_DMG_TYPE_PBSS)
1206                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1207         } else {
1208                 if (res->pub.capability & WLAN_CAPABILITY_ESS)
1209                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1210         }
1211 
1212         trace_cfg80211_return_bss(&res->pub);
1213         /* cfg80211_bss_update gives us a referenced result */
1214         return &res->pub;
1215 }
1216 EXPORT_SYMBOL(cfg80211_inform_bss_data);
1217 
1218 /* cfg80211_inform_bss_width_frame helper */
1219 struct cfg80211_bss *
1220 cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
1221                                struct cfg80211_inform_bss *data,
1222                                struct ieee80211_mgmt *mgmt, size_t len,
1223                                gfp_t gfp)
1224 
1225 {
1226         struct cfg80211_internal_bss tmp = {}, *res;
1227         struct cfg80211_bss_ies *ies;
1228         struct ieee80211_channel *channel;
1229         bool signal_valid;
1230         size_t ielen = len - offsetof(struct ieee80211_mgmt,
1231                                       u.probe_resp.variable);
1232         int bss_type;
1233 
1234         BUILD_BUG_ON(offsetof(struct ieee80211_mgmt, u.probe_resp.variable) !=
1235                         offsetof(struct ieee80211_mgmt, u.beacon.variable));
1236 
1237         trace_cfg80211_inform_bss_frame(wiphy, data, mgmt, len);
1238 
1239         if (WARN_ON(!mgmt))
1240                 return NULL;
1241 
1242         if (WARN_ON(!wiphy))
1243                 return NULL;
1244 
1245         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
1246                     (data->signal < 0 || data->signal > 100)))
1247                 return NULL;
1248 
1249         if (WARN_ON(len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
1250                 return NULL;
1251 
1252         channel = cfg80211_get_bss_channel(wiphy, mgmt->u.beacon.variable,
1253                                            ielen, data->chan, data->scan_width);
1254         if (!channel)
1255                 return NULL;
1256 
1257         ies = kzalloc(sizeof(*ies) + ielen, gfp);
1258         if (!ies)
1259                 return NULL;
1260         ies->len = ielen;
1261         ies->tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
1262         ies->from_beacon = ieee80211_is_beacon(mgmt->frame_control);
1263         memcpy(ies->data, mgmt->u.probe_resp.variable, ielen);
1264 
1265         if (ieee80211_is_probe_resp(mgmt->frame_control))
1266                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1267         else
1268                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1269         rcu_assign_pointer(tmp.pub.ies, ies);
1270 
1271         memcpy(tmp.pub.bssid, mgmt->bssid, ETH_ALEN);
1272         tmp.pub.channel = channel;
1273         tmp.pub.scan_width = data->scan_width;
1274         tmp.pub.signal = data->signal;
1275         tmp.pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
1276         tmp.pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
1277         tmp.ts_boottime = data->boottime_ns;
1278         tmp.parent_tsf = data->parent_tsf;
1279         tmp.pub.chains = data->chains;
1280         memcpy(tmp.pub.chain_signal, data->chain_signal, IEEE80211_MAX_CHAINS);
1281         ether_addr_copy(tmp.parent_bssid, data->parent_bssid);
1282 
1283         signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
1284                 wiphy->max_adj_channel_rssi_comp;
1285         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1286         if (!res)
1287                 return NULL;
1288 
1289         if (channel->band == NL80211_BAND_60GHZ) {
1290                 bss_type = res->pub.capability & WLAN_CAPABILITY_DMG_TYPE_MASK;
1291                 if (bss_type == WLAN_CAPABILITY_DMG_TYPE_AP ||
1292                     bss_type == WLAN_CAPABILITY_DMG_TYPE_PBSS)
1293                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1294         } else {
1295                 if (res->pub.capability & WLAN_CAPABILITY_ESS)
1296                         regulatory_hint_found_beacon(wiphy, channel, gfp);
1297         }
1298 
1299         trace_cfg80211_return_bss(&res->pub);
1300         /* cfg80211_bss_update gives us a referenced result */
1301         return &res->pub;
1302 }
1303 EXPORT_SYMBOL(cfg80211_inform_bss_frame_data);
1304 
1305 void cfg80211_ref_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1306 {
1307         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1308         struct cfg80211_internal_bss *bss;
1309 
1310         if (!pub)
1311                 return;
1312 
1313         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1314 
1315         spin_lock_bh(&rdev->bss_lock);
1316         bss_ref_get(rdev, bss);
1317         spin_unlock_bh(&rdev->bss_lock);
1318 }
1319 EXPORT_SYMBOL(cfg80211_ref_bss);
1320 
1321 void cfg80211_put_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1322 {
1323         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1324         struct cfg80211_internal_bss *bss;
1325 
1326         if (!pub)
1327                 return;
1328 
1329         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1330 
1331         spin_lock_bh(&rdev->bss_lock);
1332         bss_ref_put(rdev, bss);
1333         spin_unlock_bh(&rdev->bss_lock);
1334 }
1335 EXPORT_SYMBOL(cfg80211_put_bss);
1336 
1337 void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1338 {
1339         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1340         struct cfg80211_internal_bss *bss;
1341 
1342         if (WARN_ON(!pub))
1343                 return;
1344 
1345         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1346 
1347         spin_lock_bh(&rdev->bss_lock);
1348         if (!list_empty(&bss->list)) {
1349                 if (__cfg80211_unlink_bss(rdev, bss))
1350                         rdev->bss_generation++;
1351         }
1352         spin_unlock_bh(&rdev->bss_lock);
1353 }
1354 EXPORT_SYMBOL(cfg80211_unlink_bss);
1355 
1356 #ifdef CONFIG_CFG80211_WEXT
1357 static struct cfg80211_registered_device *
1358 cfg80211_get_dev_from_ifindex(struct net *net, int ifindex)
1359 {
1360         struct cfg80211_registered_device *rdev;
1361         struct net_device *dev;
1362 
1363         ASSERT_RTNL();
1364 
1365         dev = dev_get_by_index(net, ifindex);
1366         if (!dev)
1367                 return ERR_PTR(-ENODEV);
1368         if (dev->ieee80211_ptr)
1369                 rdev = wiphy_to_rdev(dev->ieee80211_ptr->wiphy);
1370         else
1371                 rdev = ERR_PTR(-ENODEV);
1372         dev_put(dev);
1373         return rdev;
1374 }
1375 
1376 int cfg80211_wext_siwscan(struct net_device *dev,
1377                           struct iw_request_info *info,
1378                           union iwreq_data *wrqu, char *extra)
1379 {
1380         struct cfg80211_registered_device *rdev;
1381         struct wiphy *wiphy;
1382         struct iw_scan_req *wreq = NULL;
1383         struct cfg80211_scan_request *creq = NULL;
1384         int i, err, n_channels = 0;
1385         enum nl80211_band band;
1386 
1387         if (!netif_running(dev))
1388                 return -ENETDOWN;
1389 
1390         if (wrqu->data.length == sizeof(struct iw_scan_req))
1391                 wreq = (struct iw_scan_req *)extra;
1392 
1393         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1394 
1395         if (IS_ERR(rdev))
1396                 return PTR_ERR(rdev);
1397 
1398         if (rdev->scan_req || rdev->scan_msg) {
1399                 err = -EBUSY;
1400                 goto out;
1401         }
1402 
1403         wiphy = &rdev->wiphy;
1404 
1405         /* Determine number of channels, needed to allocate creq */
1406         if (wreq && wreq->num_channels)
1407                 n_channels = wreq->num_channels;
1408         else
1409                 n_channels = ieee80211_get_num_supported_channels(wiphy);
1410 
1411         creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
1412                        n_channels * sizeof(void *),
1413                        GFP_ATOMIC);
1414         if (!creq) {
1415                 err = -ENOMEM;
1416                 goto out;
1417         }
1418 
1419         creq->wiphy = wiphy;
1420         creq->wdev = dev->ieee80211_ptr;
1421         /* SSIDs come after channels */
1422         creq->ssids = (void *)&creq->channels[n_channels];
1423         creq->n_channels = n_channels;
1424         creq->n_ssids = 1;
1425         creq->scan_start = jiffies;
1426 
1427         /* translate "Scan on frequencies" request */
1428         i = 0;
1429         for (band = 0; band < NUM_NL80211_BANDS; band++) {
1430                 int j;
1431 
1432                 if (!wiphy->bands[band])
1433                         continue;
1434 
1435                 for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
1436                         /* ignore disabled channels */
1437                         if (wiphy->bands[band]->channels[j].flags &
1438                                                 IEEE80211_CHAN_DISABLED)
1439                                 continue;
1440 
1441                         /* If we have a wireless request structure and the
1442                          * wireless request specifies frequencies, then search
1443                          * for the matching hardware channel.
1444                          */
1445                         if (wreq && wreq->num_channels) {
1446                                 int k;
1447                                 int wiphy_freq = wiphy->bands[band]->channels[j].center_freq;
1448                                 for (k = 0; k < wreq->num_channels; k++) {
1449                                         struct iw_freq *freq =
1450                                                 &wreq->channel_list[k];
1451                                         int wext_freq =
1452                                                 cfg80211_wext_freq(freq);
1453 
1454                                         if (wext_freq == wiphy_freq)
1455                                                 goto wext_freq_found;
1456                                 }
1457                                 goto wext_freq_not_found;
1458                         }
1459 
1460                 wext_freq_found:
1461                         creq->channels[i] = &wiphy->bands[band]->channels[j];
1462                         i++;
1463                 wext_freq_not_found: ;
1464                 }
1465         }
1466         /* No channels found? */
1467         if (!i) {
1468                 err = -EINVAL;
1469                 goto out;
1470         }
1471 
1472         /* Set real number of channels specified in creq->channels[] */
1473         creq->n_channels = i;
1474 
1475         /* translate "Scan for SSID" request */
1476         if (wreq) {
1477                 if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
1478                         if (wreq->essid_len > IEEE80211_MAX_SSID_LEN) {
1479                                 err = -EINVAL;
1480                                 goto out;
1481                         }
1482                         memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
1483                         creq->ssids[0].ssid_len = wreq->essid_len;
1484                 }
1485                 if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE)
1486                         creq->n_ssids = 0;
1487         }
1488 
1489         for (i = 0; i < NUM_NL80211_BANDS; i++)
1490                 if (wiphy->bands[i])
1491                         creq->rates[i] = (1 << wiphy->bands[i]->n_bitrates) - 1;
1492 
1493         eth_broadcast_addr(creq->bssid);
1494 
1495         rdev->scan_req = creq;
1496         err = rdev_scan(rdev, creq);
1497         if (err) {
1498                 rdev->scan_req = NULL;
1499                 /* creq will be freed below */
1500         } else {
1501                 nl80211_send_scan_start(rdev, dev->ieee80211_ptr);
1502                 /* creq now owned by driver */
1503                 creq = NULL;
1504                 dev_hold(dev);
1505         }
1506  out:
1507         kfree(creq);
1508         return err;
1509 }
1510 EXPORT_WEXT_HANDLER(cfg80211_wext_siwscan);
1511 
1512 static char *ieee80211_scan_add_ies(struct iw_request_info *info,
1513                                     const struct cfg80211_bss_ies *ies,
1514                                     char *current_ev, char *end_buf)
1515 {
1516         const u8 *pos, *end, *next;
1517         struct iw_event iwe;
1518 
1519         if (!ies)
1520                 return current_ev;
1521 
1522         /*
1523          * If needed, fragment the IEs buffer (at IE boundaries) into short
1524          * enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
1525          */
1526         pos = ies->data;
1527         end = pos + ies->len;
1528 
1529         while (end - pos > IW_GENERIC_IE_MAX) {
1530                 next = pos + 2 + pos[1];
1531                 while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
1532                         next = next + 2 + next[1];
1533 
1534                 memset(&iwe, 0, sizeof(iwe));
1535                 iwe.cmd = IWEVGENIE;
1536                 iwe.u.data.length = next - pos;
1537                 current_ev = iwe_stream_add_point_check(info, current_ev,
1538                                                         end_buf, &iwe,
1539                                                         (void *)pos);
1540                 if (IS_ERR(current_ev))
1541                         return current_ev;
1542                 pos = next;
1543         }
1544 
1545         if (end > pos) {
1546                 memset(&iwe, 0, sizeof(iwe));
1547                 iwe.cmd = IWEVGENIE;
1548                 iwe.u.data.length = end - pos;
1549                 current_ev = iwe_stream_add_point_check(info, current_ev,
1550                                                         end_buf, &iwe,
1551                                                         (void *)pos);
1552                 if (IS_ERR(current_ev))
1553                         return current_ev;
1554         }
1555 
1556         return current_ev;
1557 }
1558 
1559 static char *
1560 ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,
1561               struct cfg80211_internal_bss *bss, char *current_ev,
1562               char *end_buf)
1563 {
1564         const struct cfg80211_bss_ies *ies;
1565         struct iw_event iwe;
1566         const u8 *ie;
1567         u8 buf[50];
1568         u8 *cfg, *p, *tmp;
1569         int rem, i, sig;
1570         bool ismesh = false;
1571 
1572         memset(&iwe, 0, sizeof(iwe));
1573         iwe.cmd = SIOCGIWAP;
1574         iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
1575         memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN);
1576         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1577                                                 IW_EV_ADDR_LEN);
1578         if (IS_ERR(current_ev))
1579                 return current_ev;
1580 
1581         memset(&iwe, 0, sizeof(iwe));
1582         iwe.cmd = SIOCGIWFREQ;
1583         iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq);
1584         iwe.u.freq.e = 0;
1585         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1586                                                 IW_EV_FREQ_LEN);
1587         if (IS_ERR(current_ev))
1588                 return current_ev;
1589 
1590         memset(&iwe, 0, sizeof(iwe));
1591         iwe.cmd = SIOCGIWFREQ;
1592         iwe.u.freq.m = bss->pub.channel->center_freq;
1593         iwe.u.freq.e = 6;
1594         current_ev = iwe_stream_add_event_check(info, current_ev, end_buf, &iwe,
1595                                                 IW_EV_FREQ_LEN);
1596         if (IS_ERR(current_ev))
1597                 return current_ev;
1598 
1599         if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) {
1600                 memset(&iwe, 0, sizeof(iwe));
1601                 iwe.cmd = IWEVQUAL;
1602                 iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED |
1603                                      IW_QUAL_NOISE_INVALID |
1604                                      IW_QUAL_QUAL_UPDATED;
1605                 switch (wiphy->signal_type) {
1606                 case CFG80211_SIGNAL_TYPE_MBM:
1607                         sig = bss->pub.signal / 100;
1608                         iwe.u.qual.level = sig;
1609                         iwe.u.qual.updated |= IW_QUAL_DBM;
1610                         if (sig < -110)         /* rather bad */
1611                                 sig = -110;
1612                         else if (sig > -40)     /* perfect */
1613                                 sig = -40;
1614                         /* will give a range of 0 .. 70 */
1615                         iwe.u.qual.qual = sig + 110;
1616                         break;
1617                 case CFG80211_SIGNAL_TYPE_UNSPEC:
1618                         iwe.u.qual.level = bss->pub.signal;
1619                         /* will give range 0 .. 100 */
1620                         iwe.u.qual.qual = bss->pub.signal;
1621                         break;
1622                 default:
1623                         /* not reached */
1624                         break;
1625                 }
1626                 current_ev = iwe_stream_add_event_check(info, current_ev,
1627                                                         end_buf, &iwe,
1628                                                         IW_EV_QUAL_LEN);
1629                 if (IS_ERR(current_ev))
1630                         return current_ev;
1631         }
1632 
1633         memset(&iwe, 0, sizeof(iwe));
1634         iwe.cmd = SIOCGIWENCODE;
1635         if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY)
1636                 iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
1637         else
1638                 iwe.u.data.flags = IW_ENCODE_DISABLED;
1639         iwe.u.data.length = 0;
1640         current_ev = iwe_stream_add_point_check(info, current_ev, end_buf,
1641                                                 &iwe, "");
1642         if (IS_ERR(current_ev))
1643                 return current_ev;
1644 
1645         rcu_read_lock();
1646         ies = rcu_dereference(bss->pub.ies);
1647         rem = ies->len;
1648         ie = ies->data;
1649 
1650         while (rem >= 2) {
1651                 /* invalid data */
1652                 if (ie[1] > rem - 2)
1653                         break;
1654 
1655                 switch (ie[0]) {
1656                 case WLAN_EID_SSID:
1657                         memset(&iwe, 0, sizeof(iwe));
1658                         iwe.cmd = SIOCGIWESSID;
1659                         iwe.u.data.length = ie[1];
1660                         iwe.u.data.flags = 1;
1661                         current_ev = iwe_stream_add_point_check(info,
1662                                                                 current_ev,
1663                                                                 end_buf, &iwe,
1664                                                                 (u8 *)ie + 2);
1665                         if (IS_ERR(current_ev))
1666                                 goto unlock;
1667                         break;
1668                 case WLAN_EID_MESH_ID:
1669                         memset(&iwe, 0, sizeof(iwe));
1670                         iwe.cmd = SIOCGIWESSID;
1671                         iwe.u.data.length = ie[1];
1672                         iwe.u.data.flags = 1;
1673                         current_ev = iwe_stream_add_point_check(info,
1674                                                                 current_ev,
1675                                                                 end_buf, &iwe,
1676                                                                 (u8 *)ie + 2);
1677                         if (IS_ERR(current_ev))
1678                                 goto unlock;
1679                         break;
1680                 case WLAN_EID_MESH_CONFIG:
1681                         ismesh = true;
1682                         if (ie[1] != sizeof(struct ieee80211_meshconf_ie))
1683                                 break;
1684                         cfg = (u8 *)ie + 2;
1685                         memset(&iwe, 0, sizeof(iwe));
1686                         iwe.cmd = IWEVCUSTOM;
1687                         sprintf(buf, "Mesh Network Path Selection Protocol ID: "
1688                                 "0x%02X", cfg[0]);
1689                         iwe.u.data.length = strlen(buf);
1690                         current_ev = iwe_stream_add_point_check(info,
1691                                                                 current_ev,
1692                                                                 end_buf,
1693                                                                 &iwe, buf);
1694                         if (IS_ERR(current_ev))
1695                                 goto unlock;
1696                         sprintf(buf, "Path Selection Metric ID: 0x%02X",
1697                                 cfg[1]);
1698                         iwe.u.data.length = strlen(buf);
1699                         current_ev = iwe_stream_add_point_check(info,
1700                                                                 current_ev,
1701                                                                 end_buf,
1702                                                                 &iwe, buf);
1703                         if (IS_ERR(current_ev))
1704                                 goto unlock;
1705                         sprintf(buf, "Congestion Control Mode ID: 0x%02X",
1706                                 cfg[2]);
1707                         iwe.u.data.length = strlen(buf);
1708                         current_ev = iwe_stream_add_point_check(info,
1709                                                                 current_ev,
1710                                                                 end_buf,
1711                                                                 &iwe, buf);
1712                         if (IS_ERR(current_ev))
1713                                 goto unlock;
1714                         sprintf(buf, "Synchronization ID: 0x%02X", cfg[3]);
1715                         iwe.u.data.length = strlen(buf);
1716                         current_ev = iwe_stream_add_point_check(info,
1717                                                                 current_ev,
1718                                                                 end_buf,
1719                                                                 &iwe, buf);
1720                         if (IS_ERR(current_ev))
1721                                 goto unlock;
1722                         sprintf(buf, "Authentication ID: 0x%02X", cfg[4]);
1723                         iwe.u.data.length = strlen(buf);
1724                         current_ev = iwe_stream_add_point_check(info,
1725                                                                 current_ev,
1726                                                                 end_buf,
1727                                                                 &iwe, buf);
1728                         if (IS_ERR(current_ev))
1729                                 goto unlock;
1730                         sprintf(buf, "Formation Info: 0x%02X", cfg[5]);
1731                         iwe.u.data.length = strlen(buf);
1732                         current_ev = iwe_stream_add_point_check(info,
1733                                                                 current_ev,
1734                                                                 end_buf,
1735                                                                 &iwe, buf);
1736                         if (IS_ERR(current_ev))
1737                                 goto unlock;
1738                         sprintf(buf, "Capabilities: 0x%02X", cfg[6]);
1739                         iwe.u.data.length = strlen(buf);
1740                         current_ev = iwe_stream_add_point_check(info,
1741                                                                 current_ev,
1742                                                                 end_buf,
1743                                                                 &iwe, buf);
1744                         if (IS_ERR(current_ev))
1745                                 goto unlock;
1746                         break;
1747                 case WLAN_EID_SUPP_RATES:
1748                 case WLAN_EID_EXT_SUPP_RATES:
1749                         /* display all supported rates in readable format */
1750                         p = current_ev + iwe_stream_lcp_len(info);
1751 
1752                         memset(&iwe, 0, sizeof(iwe));
1753                         iwe.cmd = SIOCGIWRATE;
1754                         /* Those two flags are ignored... */
1755                         iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;
1756 
1757                         for (i = 0; i < ie[1]; i++) {
1758                                 iwe.u.bitrate.value =
1759                                         ((ie[i + 2] & 0x7f) * 500000);
1760                                 tmp = p;
1761                                 p = iwe_stream_add_value(info, current_ev, p,
1762                                                          end_buf, &iwe,
1763                                                          IW_EV_PARAM_LEN);
1764                                 if (p == tmp) {
1765                                         current_ev = ERR_PTR(-E2BIG);
1766                                         goto unlock;
1767                                 }
1768                         }
1769                         current_ev = p;
1770                         break;
1771                 }
1772                 rem -= ie[1] + 2;
1773                 ie += ie[1] + 2;
1774         }
1775 
1776         if (bss->pub.capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS) ||
1777             ismesh) {
1778                 memset(&iwe, 0, sizeof(iwe));
1779                 iwe.cmd = SIOCGIWMODE;
1780                 if (ismesh)
1781                         iwe.u.mode = IW_MODE_MESH;
1782                 else if (bss->pub.capability & WLAN_CAPABILITY_ESS)
1783                         iwe.u.mode = IW_MODE_MASTER;
1784                 else
1785                         iwe.u.mode = IW_MODE_ADHOC;
1786                 current_ev = iwe_stream_add_event_check(info, current_ev,
1787                                                         end_buf, &iwe,
1788                                                         IW_EV_UINT_LEN);
1789                 if (IS_ERR(current_ev))
1790                         goto unlock;
1791         }
1792 
1793         memset(&iwe, 0, sizeof(iwe));
1794         iwe.cmd = IWEVCUSTOM;
1795         sprintf(buf, "tsf=%016llx", (unsigned long long)(ies->tsf));
1796         iwe.u.data.length = strlen(buf);
1797         current_ev = iwe_stream_add_point_check(info, current_ev, end_buf,
1798                                                 &iwe, buf);
1799         if (IS_ERR(current_ev))
1800                 goto unlock;
1801         memset(&iwe, 0, sizeof(iwe));
1802         iwe.cmd = IWEVCUSTOM;
1803         sprintf(buf, " Last beacon: %ums ago",
1804                 elapsed_jiffies_msecs(bss->ts));
1805         iwe.u.data.length = strlen(buf);
1806         current_ev = iwe_stream_add_point_check(info, current_ev,
1807                                                 end_buf, &iwe, buf);
1808         if (IS_ERR(current_ev))
1809                 goto unlock;
1810 
1811         current_ev = ieee80211_scan_add_ies(info, ies, current_ev, end_buf);
1812 
1813  unlock:
1814         rcu_read_unlock();
1815         return current_ev;
1816 }
1817 
1818 
1819 static int ieee80211_scan_results(struct cfg80211_registered_device *rdev,
1820                                   struct iw_request_info *info,
1821                                   char *buf, size_t len)
1822 {
1823         char *current_ev = buf;
1824         char *end_buf = buf + len;
1825         struct cfg80211_internal_bss *bss;
1826         int err = 0;
1827 
1828         spin_lock_bh(&rdev->bss_lock);
1829         cfg80211_bss_expire(rdev);
1830 
1831         list_for_each_entry(bss, &rdev->bss_list, list) {
1832                 if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
1833                         err = -E2BIG;
1834                         break;
1835                 }
1836                 current_ev = ieee80211_bss(&rdev->wiphy, info, bss,
1837                                            current_ev, end_buf);
1838                 if (IS_ERR(current_ev)) {
1839                         err = PTR_ERR(current_ev);
1840                         break;
1841                 }
1842         }
1843         spin_unlock_bh(&rdev->bss_lock);
1844 
1845         if (err)
1846                 return err;
1847         return current_ev - buf;
1848 }
1849 
1850 
1851 int cfg80211_wext_giwscan(struct net_device *dev,
1852                           struct iw_request_info *info,
1853                           struct iw_point *data, char *extra)
1854 {
1855         struct cfg80211_registered_device *rdev;
1856         int res;
1857 
1858         if (!netif_running(dev))
1859                 return -ENETDOWN;
1860 
1861         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1862 
1863         if (IS_ERR(rdev))
1864                 return PTR_ERR(rdev);
1865 
1866         if (rdev->scan_req || rdev->scan_msg)
1867                 return -EAGAIN;
1868 
1869         res = ieee80211_scan_results(rdev, info, extra, data->length);
1870         data->length = 0;
1871         if (res >= 0) {
1872                 data->length = res;
1873                 res = 0;
1874         }
1875 
1876         return res;
1877 }
1878 EXPORT_WEXT_HANDLER(cfg80211_wext_giwscan);
1879 #endif
1880 

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