net/wireless/scan.c

   1 /*
   2  * cfg80211 scan result handling
   3  *
   4  * Copyright 2008 Johannes Berg <johannes@sipsolutions.net>
   5  * Copyright 2013-2014  Intel Mobile Communications GmbH
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/slab.h>
   9 #include <linux/module.h>
  10 #include <linux/netdevice.h>
  11 #include <linux/wireless.h>
  12 #include <linux/nl80211.h>
  13 #include <linux/etherdevice.h>
  14 #include <net/arp.h>
  15 #include <net/cfg80211.h>
  16 #include <net/cfg80211-wext.h>
  17 #include <net/iw_handler.h>
  18 #include "core.h"
  19 #include "nl80211.h"
  20 #include "wext-compat.h"
  21 #include "rdev-ops.h"
  22
  23 /**
  24  * DOC: BSS tree/list structure
  25  *
  26  * At the top level, the BSS list is kept in both a list in each
  27  * registered device (@bss_list) as well as an RB-tree for faster
  28  * lookup. In the RB-tree, entries can be looked up using their
  29  * channel, MESHID, MESHCONF (for MBSSes) or channel, BSSID, SSID
  30  * for other BSSes.
  31  *
  32  * Due to the possibility of hidden SSIDs, there's a second level
  33  * structure, the "hidden_list" and "hidden_beacon_bss" pointer.
  34  * The hidden_list connects all BSSes belonging to a single AP
  35  * that has a hidden SSID, and connects beacon and probe response
  36  * entries. For a probe response entry for a hidden SSID, the
  37  * hidden_beacon_bss pointer points to the BSS struct holding the
  38  * beacon's information.
  39  *
  40  * Reference counting is done for all these references except for
  41  * the hidden_list, so that a beacon BSS struct that is otherwise
  42  * not referenced has one reference for being on the bss_list and
  43  * one for each probe response entry that points to it using the
  44  * hidden_beacon_bss pointer. When a BSS struct that has such a
  45  * pointer is get/put, the refcount update is also propagated to
  46  * the referenced struct, this ensure that it cannot get removed
  47  * while somebody is using the probe response version.
  48  *
  49  * Note that the hidden_beacon_bss pointer never changes, due to
  50  * the reference counting. Therefore, no locking is needed for
  51  * it.
  52  *
  53  * Also note that the hidden_beacon_bss pointer is only relevant
  54  * if the driver uses something other than the IEs, e.g. private
  55  * data stored stored in the BSS struct, since the beacon IEs are
  56  * also linked into the probe response struct.
  57  */
  58
  59 #define IEEE80211_SCAN_RESULT_EXPIRE    (30 * HZ)
  60
  61 static void bss_free(struct cfg80211_internal_bss *bss)
  62 {
  63         struct cfg80211_bss_ies *ies;
  64
  65         if (WARN_ON(atomic_read(&bss->hold)))
  66                 return;
  67
  68         ies = (void *)rcu_access_pointer(bss->pub.beacon_ies);
  69         if (ies && !bss->pub.hidden_beacon_bss)
  70                 kfree_rcu(ies, rcu_head);
  71         ies = (void *)rcu_access_pointer(bss->pub.proberesp_ies);
  72         if (ies)
  73                 kfree_rcu(ies, rcu_head);
  74
  75         /*
  76          * This happens when the module is removed, it doesn't
  77          * really matter any more save for completeness
  78          */
  79         if (!list_empty(&bss->hidden_list))
  80                 list_del(&bss->hidden_list);
  81
  82         kfree(bss);
  83 }
  84
  85 static inline void bss_ref_get(struct cfg80211_registered_device *rdev,
  86                                struct cfg80211_internal_bss *bss)
  87 {
  88         lockdep_assert_held(&rdev->bss_lock);
  89
  90         bss->refcount++;
  91         if (bss->pub.hidden_beacon_bss) {
  92                 bss = container_of(bss->pub.hidden_beacon_bss,
  93                                    struct cfg80211_internal_bss,
  94                                    pub);
  95                 bss->refcount++;
  96         }
  97 }
  98
  99 static inline void bss_ref_put(struct cfg80211_registered_device *rdev,
 100                                struct cfg80211_internal_bss *bss)
 101 {
 102         lockdep_assert_held(&rdev->bss_lock);
 103
 104         if (bss->pub.hidden_beacon_bss) {
 105                 struct cfg80211_internal_bss *hbss;
 106                 hbss = container_of(bss->pub.hidden_beacon_bss,
 107                                     struct cfg80211_internal_bss,
 108                                     pub);
 109                 hbss->refcount--;
 110                 if (hbss->refcount == 0)
 111                         bss_free(hbss);
 112         }
 113         bss->refcount--;
 114         if (bss->refcount == 0)
 115                 bss_free(bss);
 116 }
 117
 118 static bool __cfg80211_unlink_bss(struct cfg80211_registered_device *rdev,
 119                                   struct cfg80211_internal_bss *bss)
 120 {
 121         lockdep_assert_held(&rdev->bss_lock);
 122
 123         if (!list_empty(&bss->hidden_list)) {
 124                 /*
 125                  * don't remove the beacon entry if it has
 126                  * probe responses associated with it
 127                  */
 128                 if (!bss->pub.hidden_beacon_bss)
 129                         return false;
 130                 /*
 131                  * if it's a probe response entry break its
 132                  * link to the other entries in the group
 133                  */
 134                 list_del_init(&bss->hidden_list);
 135         }
 136
 137         list_del_init(&bss->list);
 138         rb_erase(&bss->rbn, &rdev->bss_tree);
 139         bss_ref_put(rdev, bss);
 140         return true;
 141 }
 142
 143 static void __cfg80211_bss_expire(struct cfg80211_registered_device *rdev,
 144                                   unsigned long expire_time)
 145 {
 146         struct cfg80211_internal_bss *bss, *tmp;
 147         bool expired = false;
 148
 149         lockdep_assert_held(&rdev->bss_lock);
 150
 151         list_for_each_entry_safe(bss, tmp, &rdev->bss_list, list) {
 152                 if (atomic_read(&bss->hold))
 153                         continue;
 154                 if (!time_after(expire_time, bss->ts))
 155                         continue;
 156
 157                 if (__cfg80211_unlink_bss(rdev, bss))
 158                         expired = true;
 159         }
 160
 161         if (expired)
 162                 rdev->bss_generation++;
 163 }
 164
 165 void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev,
 166                            bool send_message)
 167 {
 168         struct cfg80211_scan_request *request;
 169         struct wireless_dev *wdev;
 170         struct sk_buff *msg;
 171 #ifdef CONFIG_CFG80211_WEXT
 172         union iwreq_data wrqu;
 173 #endif
 174
 175         ASSERT_RTNL();
 176
 177         if (rdev->scan_msg) {
 178                 nl80211_send_scan_result(rdev, rdev->scan_msg);
 179                 rdev->scan_msg = NULL;
 180                 return;
 181         }
 182
 183         request = rdev->scan_req;
 184         if (!request)
 185                 return;
 186
 187         wdev = request->wdev;
 188
 189         /*
 190          * This must be before sending the other events!
 191          * Otherwise, wpa_supplicant gets completely confused with
 192          * wext events.
 193          */
 194         if (wdev->netdev)
 195                 cfg80211_sme_scan_done(wdev->netdev);
 196
 197         if (!request->aborted &&
 198             request->flags & NL80211_SCAN_FLAG_FLUSH) {
 199                 /* flush entries from previous scans */
 200                 spin_lock_bh(&rdev->bss_lock);
 201                 __cfg80211_bss_expire(rdev, request->scan_start);
 202                 spin_unlock_bh(&rdev->bss_lock);
 203         }
 204
 205         msg = nl80211_build_scan_msg(rdev, wdev, request->aborted);
 206
 207 #ifdef CONFIG_CFG80211_WEXT
 208         if (wdev->netdev && !request->aborted) {
 209                 memset(&wrqu, 0, sizeof(wrqu));
 210
 211                 wireless_send_event(wdev->netdev, SIOCGIWSCAN, &wrqu, NULL);
 212         }
 213 #endif
 214
 215         if (wdev->netdev)
 216                 dev_put(wdev->netdev);
 217
 218         rdev->scan_req = NULL;
 219         kfree(request);
 220
 221         if (!send_message)
 222                 rdev->scan_msg = msg;
 223         else
 224                 nl80211_send_scan_result(rdev, msg);
 225 }
 226
 227 void __cfg80211_scan_done(struct work_struct *wk)
 228 {
 229         struct cfg80211_registered_device *rdev;
 230
 231         rdev = container_of(wk, struct cfg80211_registered_device,
 232                             scan_done_wk);
 233
 234         rtnl_lock();
 235         ___cfg80211_scan_done(rdev, true);
 236         rtnl_unlock();
 237 }
 238
 239 void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted)
 240 {
 241         trace_cfg80211_scan_done(request, aborted);
 242         WARN_ON(request != wiphy_to_rdev(request->wiphy)->scan_req);
 243
 244         request->aborted = aborted;
 245         request->notified = true;
 246         queue_work(cfg80211_wq, &wiphy_to_rdev(request->wiphy)->scan_done_wk);
 247 }
 248 EXPORT_SYMBOL(cfg80211_scan_done);
 249
 250 void __cfg80211_sched_scan_results(struct work_struct *wk)
 251 {
 252         struct cfg80211_registered_device *rdev;
 253         struct cfg80211_sched_scan_request *request;
 254
 255         rdev = container_of(wk, struct cfg80211_registered_device,
 256                             sched_scan_results_wk);
 257
 258         rtnl_lock();
 259
 260         request = rdev->sched_scan_req;
 261
 262         /* we don't have sched_scan_req anymore if the scan is stopping */
 263         if (request) {
 264                 if (request->flags & NL80211_SCAN_FLAG_FLUSH) {
 265                         /* flush entries from previous scans */
 266                         spin_lock_bh(&rdev->bss_lock);
 267                         __cfg80211_bss_expire(rdev, request->scan_start);
 268                         spin_unlock_bh(&rdev->bss_lock);
 269                         request->scan_start =
 270                                 jiffies + msecs_to_jiffies(request->interval);
 271                 }
 272                 nl80211_send_sched_scan_results(rdev, request->dev);
 273         }
 274
 275         rtnl_unlock();
 276 }
 277
 278 void cfg80211_sched_scan_results(struct wiphy *wiphy)
 279 {
 280         trace_cfg80211_sched_scan_results(wiphy);
 281         /* ignore if we're not scanning */
 282         if (wiphy_to_rdev(wiphy)->sched_scan_req)
 283                 queue_work(cfg80211_wq,
 284                            &wiphy_to_rdev(wiphy)->sched_scan_results_wk);
 285 }
 286 EXPORT_SYMBOL(cfg80211_sched_scan_results);
 287
 288 void cfg80211_sched_scan_stopped_rtnl(struct wiphy *wiphy)
 289 {
 290         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 291
 292         ASSERT_RTNL();
 293
 294         trace_cfg80211_sched_scan_stopped(wiphy);
 295
 296         __cfg80211_stop_sched_scan(rdev, true);
 297 }
 298 EXPORT_SYMBOL(cfg80211_sched_scan_stopped_rtnl);
 299
 300 void cfg80211_sched_scan_stopped(struct wiphy *wiphy)
 301 {
 302         rtnl_lock();
 303         cfg80211_sched_scan_stopped_rtnl(wiphy);
 304         rtnl_unlock();
 305 }
 306 EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
 307
 308 int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
 309                                bool driver_initiated)
 310 {
 311         struct net_device *dev;
 312
 313         ASSERT_RTNL();
 314
 315         if (!rdev->sched_scan_req)
 316                 return -ENOENT;
 317
 318         dev = rdev->sched_scan_req->dev;
 319
 320         if (!driver_initiated) {
 321                 int err = rdev_sched_scan_stop(rdev, dev);
 322                 if (err)
 323                         return err;
 324         }
 325
 326         nl80211_send_sched_scan(rdev, dev, NL80211_CMD_SCHED_SCAN_STOPPED);
 327
 328         kfree(rdev->sched_scan_req);
 329         rdev->sched_scan_req = NULL;
 330
 331         return 0;
 332 }
 333
 334 void cfg80211_bss_age(struct cfg80211_registered_device *rdev,
 335                       unsigned long age_secs)
 336 {
 337         struct cfg80211_internal_bss *bss;
 338         unsigned long age_jiffies = msecs_to_jiffies(age_secs * MSEC_PER_SEC);
 339
 340         spin_lock_bh(&rdev->bss_lock);
 341         list_for_each_entry(bss, &rdev->bss_list, list)
 342                 bss->ts -= age_jiffies;
 343         spin_unlock_bh(&rdev->bss_lock);
 344 }
 345
 346 void cfg80211_bss_expire(struct cfg80211_registered_device *rdev)
 347 {
 348         __cfg80211_bss_expire(rdev, jiffies - IEEE80211_SCAN_RESULT_EXPIRE);
 349 }
 350
 351 const u8 *cfg80211_find_ie(u8 eid, const u8 *ies, int len)
 352 {
 353         while (len > 2 && ies[0] != eid) {
 354                 len -= ies[1] + 2;
 355                 ies += ies[1] + 2;
 356         }
 357         if (len < 2)
 358                 return NULL;
 359         if (len < 2 + ies[1])
 360                 return NULL;
 361         return ies;
 362 }
 363 EXPORT_SYMBOL(cfg80211_find_ie);
 364
 365 const u8 *cfg80211_find_vendor_ie(unsigned int oui, u8 oui_type,
 366                                   const u8 *ies, int len)
 367 {
 368         struct ieee80211_vendor_ie *ie;
 369         const u8 *pos = ies, *end = ies + len;
 370         int ie_oui;
 371
 372         while (pos < end) {
 373                 pos = cfg80211_find_ie(WLAN_EID_VENDOR_SPECIFIC, pos,
 374                                        end - pos);
 375                 if (!pos)
 376                         return NULL;
 377
 378                 ie = (struct ieee80211_vendor_ie *)pos;
 379
 380                 /* make sure we can access ie->len */
 381                 BUILD_BUG_ON(offsetof(struct ieee80211_vendor_ie, len) != 1);
 382
 383                 if (ie->len < sizeof(*ie))
 384                         goto cont;
 385
 386                 ie_oui = ie->oui[0] << 16 | ie->oui[1] << 8 | ie->oui[2];
 387                 if (ie_oui == oui && ie->oui_type == oui_type)
 388                         return pos;
 389 cont:
 390                 pos += 2 + ie->len;
 391         }
 392         return NULL;
 393 }
 394 EXPORT_SYMBOL(cfg80211_find_vendor_ie);
 395
 396 static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
 397                    const u8 *ssid, size_t ssid_len)
 398 {
 399         const struct cfg80211_bss_ies *ies;
 400         const u8 *ssidie;
 401
 402         if (bssid && !ether_addr_equal(a->bssid, bssid))
 403                 return false;
 404
 405         if (!ssid)
 406                 return true;
 407
 408         ies = rcu_access_pointer(a->ies);
 409         if (!ies)
 410                 return false;
 411         ssidie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 412         if (!ssidie)
 413                 return false;
 414         if (ssidie[1] != ssid_len)
 415                 return false;
 416         return memcmp(ssidie + 2, ssid, ssid_len) == 0;
 417 }
 418
 419 /**
 420  * enum bss_compare_mode - BSS compare mode
 421  * @BSS_CMP_REGULAR: regular compare mode (for insertion and normal find)
 422  * @BSS_CMP_HIDE_ZLEN: find hidden SSID with zero-length mode
 423  * @BSS_CMP_HIDE_NUL: find hidden SSID with NUL-ed out mode
 424  */
 425 enum bss_compare_mode {
 426         BSS_CMP_REGULAR,
 427         BSS_CMP_HIDE_ZLEN,
 428         BSS_CMP_HIDE_NUL,
 429 };
 430
 431 static int cmp_bss(struct cfg80211_bss *a,
 432                    struct cfg80211_bss *b,
 433                    enum bss_compare_mode mode)
 434 {
 435         const struct cfg80211_bss_ies *a_ies, *b_ies;
 436         const u8 *ie1 = NULL;
 437         const u8 *ie2 = NULL;
 438         int i, r;
 439
 440         if (a->channel != b->channel)
 441                 return b->channel->center_freq - a->channel->center_freq;
 442
 443         a_ies = rcu_access_pointer(a->ies);
 444         if (!a_ies)
 445                 return -1;
 446         b_ies = rcu_access_pointer(b->ies);
 447         if (!b_ies)
 448                 return 1;
 449
 450         if (WLAN_CAPABILITY_IS_STA_BSS(a->capability))
 451                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 452                                        a_ies->data, a_ies->len);
 453         if (WLAN_CAPABILITY_IS_STA_BSS(b->capability))
 454                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 455                                        b_ies->data, b_ies->len);
 456         if (ie1 && ie2) {
 457                 int mesh_id_cmp;
 458
 459                 if (ie1[1] == ie2[1])
 460                         mesh_id_cmp = memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 461                 else
 462                         mesh_id_cmp = ie2[1] - ie1[1];
 463
 464                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 465                                        a_ies->data, a_ies->len);
 466                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 467                                        b_ies->data, b_ies->len);
 468                 if (ie1 && ie2) {
 469                         if (mesh_id_cmp)
 470                                 return mesh_id_cmp;
 471                         if (ie1[1] != ie2[1])
 472                                 return ie2[1] - ie1[1];
 473                         return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 474                 }
 475         }
 476
 477         r = memcmp(a->bssid, b->bssid, sizeof(a->bssid));
 478         if (r)
 479                 return r;
 480
 481         ie1 = cfg80211_find_ie(WLAN_EID_SSID, a_ies->data, a_ies->len);
 482         ie2 = cfg80211_find_ie(WLAN_EID_SSID, b_ies->data, b_ies->len);
 483
 484         if (!ie1 && !ie2)
 485                 return 0;
 486
 487         /*
 488          * Note that with "hide_ssid", the function returns a match if
 489          * the already-present BSS ("b") is a hidden SSID beacon for
 490          * the new BSS ("a").
 491          */
 492
 493         /* sort missing IE before (left of) present IE */
 494         if (!ie1)
 495                 return -1;
 496         if (!ie2)
 497                 return 1;
 498
 499         switch (mode) {
 500         case BSS_CMP_HIDE_ZLEN:
 501                 /*
 502                  * In ZLEN mode we assume the BSS entry we're
 503                  * looking for has a zero-length SSID. So if
 504                  * the one we're looking at right now has that,
 505                  * return 0. Otherwise, return the difference
 506                  * in length, but since we're looking for the
 507                  * 0-length it's really equivalent to returning
 508                  * the length of the one we're looking at.
 509                  *
 510                  * No content comparison is needed as we assume
 511                  * the content length is zero.
 512                  */
 513                 return ie2[1];
 514         case BSS_CMP_REGULAR:
 515         default:
 516                 /* sort by length first, then by contents */
 517                 if (ie1[1] != ie2[1])
 518                         return ie2[1] - ie1[1];
 519                 return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 520         case BSS_CMP_HIDE_NUL:
 521                 if (ie1[1] != ie2[1])
 522                         return ie2[1] - ie1[1];
 523                 /* this is equivalent to memcmp(zeroes, ie2 + 2, len) */
 524                 for (i = 0; i < ie2[1]; i++)
 525                         if (ie2[i + 2])
 526                                 return -1;
 527                 return 0;
 528         }
 529 }
 530
 531 /* Returned bss is reference counted and must be cleaned up appropriately. */
 532 struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
 533                                       struct ieee80211_channel *channel,
 534                                       const u8 *bssid,
 535                                       const u8 *ssid, size_t ssid_len,
 536                                       u16 capa_mask, u16 capa_val)
 537 {
 538         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 539         struct cfg80211_internal_bss *bss, *res = NULL;
 540         unsigned long now = jiffies;
 541
 542         trace_cfg80211_get_bss(wiphy, channel, bssid, ssid, ssid_len, capa_mask,
 543                                capa_val);
 544
 545         spin_lock_bh(&rdev->bss_lock);
 546
 547         list_for_each_entry(bss, &rdev->bss_list, list) {
 548                 if ((bss->pub.capability & capa_mask) != capa_val)
 549                         continue;
 550                 if (channel && bss->pub.channel != channel)
 551                         continue;
 552                 if (!is_valid_ether_addr(bss->pub.bssid))
 553                         continue;
 554                 /* Don't get expired BSS structs */
 555                 if (time_after(now, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE) &&
 556                     !atomic_read(&bss->hold))
 557                         continue;
 558                 if (is_bss(&bss->pub, bssid, ssid, ssid_len)) {
 559                         res = bss;
 560                         bss_ref_get(rdev, res);
 561                         break;
 562                 }
 563         }
 564
 565         spin_unlock_bh(&rdev->bss_lock);
 566         if (!res)
 567                 return NULL;
 568         trace_cfg80211_return_bss(&res->pub);
 569         return &res->pub;
 570 }
 571 EXPORT_SYMBOL(cfg80211_get_bss);
 572
 573 static void rb_insert_bss(struct cfg80211_registered_device *rdev,
 574                           struct cfg80211_internal_bss *bss)
 575 {
 576         struct rb_node **p = &rdev->bss_tree.rb_node;
 577         struct rb_node *parent = NULL;
 578         struct cfg80211_internal_bss *tbss;
 579         int cmp;
 580
 581         while (*p) {
 582                 parent = *p;
 583                 tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);
 584
 585                 cmp = cmp_bss(&bss->pub, &tbss->pub, BSS_CMP_REGULAR);
 586
 587                 if (WARN_ON(!cmp)) {
 588                         /* will sort of leak this BSS */
 589                         return;
 590                 }
 591
 592                 if (cmp < 0)
 593                         p = &(*p)->rb_left;
 594                 else
 595                         p = &(*p)->rb_right;
 596         }
 597
 598         rb_link_node(&bss->rbn, parent, p);
 599         rb_insert_color(&bss->rbn, &rdev->bss_tree);
 600 }
 601
 602 static struct cfg80211_internal_bss *
 603 rb_find_bss(struct cfg80211_registered_device *rdev,
 604             struct cfg80211_internal_bss *res,
 605             enum bss_compare_mode mode)
 606 {
 607         struct rb_node *n = rdev->bss_tree.rb_node;
 608         struct cfg80211_internal_bss *bss;
 609         int r;
 610
 611         while (n) {
 612                 bss = rb_entry(n, struct cfg80211_internal_bss, rbn);
 613                 r = cmp_bss(&res->pub, &bss->pub, mode);
 614
 615                 if (r == 0)
 616                         return bss;
 617                 else if (r < 0)
 618                         n = n->rb_left;
 619                 else
 620                         n = n->rb_right;
 621         }
 622
 623         return NULL;
 624 }
 625
 626 static bool cfg80211_combine_bsses(struct cfg80211_registered_device *rdev,
 627                                    struct cfg80211_internal_bss *new)
 628 {
 629         const struct cfg80211_bss_ies *ies;
 630         struct cfg80211_internal_bss *bss;
 631         const u8 *ie;
 632         int i, ssidlen;
 633         u8 fold = 0;
 634
 635         ies = rcu_access_pointer(new->pub.beacon_ies);
 636         if (WARN_ON(!ies))
 637                 return false;
 638
 639         ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 640         if (!ie) {
 641                 /* nothing to do */
 642                 return true;
 643         }
 644
 645         ssidlen = ie[1];
 646         for (i = 0; i < ssidlen; i++)
 647                 fold |= ie[2 + i];
 648
 649         if (fold) {
 650                 /* not a hidden SSID */
 651                 return true;
 652         }
 653
 654         /* This is the bad part ... */
 655
 656         list_for_each_entry(bss, &rdev->bss_list, list) {
 657                 if (!ether_addr_equal(bss->pub.bssid, new->pub.bssid))
 658                         continue;
 659                 if (bss->pub.channel != new->pub.channel)
 660                         continue;
 661                 if (bss->pub.scan_width != new->pub.scan_width)
 662                         continue;
 663                 if (rcu_access_pointer(bss->pub.beacon_ies))
 664                         continue;
 665                 ies = rcu_access_pointer(bss->pub.ies);
 666                 if (!ies)
 667                         continue;
 668                 ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 669                 if (!ie)
 670                         continue;
 671                 if (ssidlen && ie[1] != ssidlen)
 672                         continue;
 673                 if (WARN_ON_ONCE(bss->pub.hidden_beacon_bss))
 674                         continue;
 675                 if (WARN_ON_ONCE(!list_empty(&bss->hidden_list)))
 676                         list_del(&bss->hidden_list);
 677                 /* combine them */
 678                 list_add(&bss->hidden_list, &new->hidden_list);
 679                 bss->pub.hidden_beacon_bss = &new->pub;
 680                 new->refcount += bss->refcount;
 681                 rcu_assign_pointer(bss->pub.beacon_ies,
 682                                    new->pub.beacon_ies);
 683         }
 684
 685         return true;
 686 }
 687
 688 /* Returned bss is reference counted and must be cleaned up appropriately. */
 689 static struct cfg80211_internal_bss *
 690 cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 691                     struct cfg80211_internal_bss *tmp,
 692                     bool signal_valid)
 693 {
 694         struct cfg80211_internal_bss *found = NULL;
 695
 696         if (WARN_ON(!tmp->pub.channel))
 697                 return NULL;
 698
 699         tmp->ts = jiffies;
 700
 701         spin_lock_bh(&rdev->bss_lock);
 702
 703         if (WARN_ON(!rcu_access_pointer(tmp->pub.ies))) {
 704                 spin_unlock_bh(&rdev->bss_lock);
 705                 return NULL;
 706         }
 707
 708         found = rb_find_bss(rdev, tmp, BSS_CMP_REGULAR);
 709
 710         if (found) {
 711                 /* Update IEs */
 712                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
 713                         const struct cfg80211_bss_ies *old;
 714
 715                         old = rcu_access_pointer(found->pub.proberesp_ies);
 716
 717                         rcu_assign_pointer(found->pub.proberesp_ies,
 718                                            tmp->pub.proberesp_ies);
 719                         /* Override possible earlier Beacon frame IEs */
 720                         rcu_assign_pointer(found->pub.ies,
 721                                            tmp->pub.proberesp_ies);
 722                         if (old)
 723                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 724                                           rcu_head);
 725                 } else if (rcu_access_pointer(tmp->pub.beacon_ies)) {
 726                         const struct cfg80211_bss_ies *old;
 727                         struct cfg80211_internal_bss *bss;
 728
 729                         if (found->pub.hidden_beacon_bss &&
 730                             !list_empty(&found->hidden_list)) {
 731                                 const struct cfg80211_bss_ies *f;
 732
 733                                 /*
 734                                  * The found BSS struct is one of the probe
 735                                  * response members of a group, but we're
 736                                  * receiving a beacon (beacon_ies in the tmp
 737                                  * bss is used). This can only mean that the
 738                                  * AP changed its beacon from not having an
 739                                  * SSID to showing it, which is confusing so
 740                                  * drop this information.
 741                                  */
 742
 743                                 f = rcu_access_pointer(tmp->pub.beacon_ies);
 744                                 kfree_rcu((struct cfg80211_bss_ies *)f,
 745                                           rcu_head);
 746                                 goto drop;
 747                         }
 748
 749                         old = rcu_access_pointer(found->pub.beacon_ies);
 750
 751                         rcu_assign_pointer(found->pub.beacon_ies,
 752                                            tmp->pub.beacon_ies);
 753
 754                         /* Override IEs if they were from a beacon before */
 755                         if (old == rcu_access_pointer(found->pub.ies))
 756                                 rcu_assign_pointer(found->pub.ies,
 757                                                    tmp->pub.beacon_ies);
 758
 759                         /* Assign beacon IEs to all sub entries */
 760                         list_for_each_entry(bss, &found->hidden_list,
 761                                             hidden_list) {
 762                                 const struct cfg80211_bss_ies *ies;
 763
 764                                 ies = rcu_access_pointer(bss->pub.beacon_ies);
 765                                 WARN_ON(ies != old);
 766
 767                                 rcu_assign_pointer(bss->pub.beacon_ies,
 768                                                    tmp->pub.beacon_ies);
 769                         }
 770
 771                         if (old)
 772                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 773                                           rcu_head);
 774                 }
 775
 776                 found->pub.beacon_interval = tmp->pub.beacon_interval;
 777                 /*
 778                  * don't update the signal if beacon was heard on
 779                  * adjacent channel.
 780                  */
 781                 if (signal_valid)
 782                         found->pub.signal = tmp->pub.signal;
 783                 found->pub.capability = tmp->pub.capability;
 784                 found->ts = tmp->ts;
 785         } else {
 786                 struct cfg80211_internal_bss *new;
 787                 struct cfg80211_internal_bss *hidden;
 788                 struct cfg80211_bss_ies *ies;
 789
 790                 /*
 791                  * create a copy -- the "res" variable that is passed in
 792                  * is allocated on the stack since it's not needed in the
 793                  * more common case of an update
 794                  */
 795                 new = kzalloc(sizeof(*new) + rdev->wiphy.bss_priv_size,
 796                               GFP_ATOMIC);
 797                 if (!new) {
 798                         ies = (void *)rcu_dereference(tmp->pub.beacon_ies);
 799                         if (ies)
 800                                 kfree_rcu(ies, rcu_head);
 801                         ies = (void *)rcu_dereference(tmp->pub.proberesp_ies);
 802                         if (ies)
 803                                 kfree_rcu(ies, rcu_head);
 804                         goto drop;
 805                 }
 806                 memcpy(new, tmp, sizeof(*new));
 807                 new->refcount = 1;
 808                 INIT_LIST_HEAD(&new->hidden_list);
 809
 810                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
 811                         hidden = rb_find_bss(rdev, tmp, BSS_CMP_HIDE_ZLEN);
 812                         if (!hidden)
 813                                 hidden = rb_find_bss(rdev, tmp,
 814                                                      BSS_CMP_HIDE_NUL);
 815                         if (hidden) {
 816                                 new->pub.hidden_beacon_bss = &hidden->pub;
 817                                 list_add(&new->hidden_list,
 818                                          &hidden->hidden_list);
 819                                 hidden->refcount++;
 820                                 rcu_assign_pointer(new->pub.beacon_ies,
 821                                                    hidden->pub.beacon_ies);
 822                         }
 823                 } else {
 824                         /*
 825                          * Ok so we found a beacon, and don't have an entry. If
 826                          * it's a beacon with hidden SSID, we might be in for an
 827                          * expensive search for any probe responses that should
 828                          * be grouped with this beacon for updates ...
 829                          */
 830                         if (!cfg80211_combine_bsses(rdev, new)) {
 831                                 kfree(new);
 832                                 goto drop;
 833                         }
 834                 }
 835
 836                 list_add_tail(&new->list, &rdev->bss_list);
 837                 rb_insert_bss(rdev, new);
 838                 found = new;
 839         }
 840
 841         rdev->bss_generation++;
 842         bss_ref_get(rdev, found);
 843         spin_unlock_bh(&rdev->bss_lock);
 844
 845         return found;
 846  drop:
 847         spin_unlock_bh(&rdev->bss_lock);
 848         return NULL;
 849 }
 850
 851 static struct ieee80211_channel *
 852 cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
 853                          struct ieee80211_channel *channel)
 854 {
 855         const u8 *tmp;
 856         u32 freq;
 857         int channel_number = -1;
 858
 859         tmp = cfg80211_find_ie(WLAN_EID_DS_PARAMS, ie, ielen);
 860         if (tmp && tmp[1] == 1) {
 861                 channel_number = tmp[2];
 862         } else {
 863                 tmp = cfg80211_find_ie(WLAN_EID_HT_OPERATION, ie, ielen);
 864                 if (tmp && tmp[1] >= sizeof(struct ieee80211_ht_operation)) {
 865                         struct ieee80211_ht_operation *htop = (void *)(tmp + 2);
 866
 867                         channel_number = htop->primary_chan;
 868                 }
 869         }
 870
 871         if (channel_number < 0)
 872                 return channel;
 873
 874         freq = ieee80211_channel_to_frequency(channel_number, channel->band);
 875         channel = ieee80211_get_channel(wiphy, freq);
 876         if (!channel)
 877                 return NULL;
 878         if (channel->flags & IEEE80211_CHAN_DISABLED)
 879                 return NULL;
 880         return channel;
 881 }
 882
 883 /* Returned bss is reference counted and must be cleaned up appropriately. */
 884 struct cfg80211_bss*
 885 cfg80211_inform_bss_width(struct wiphy *wiphy,
 886                           struct ieee80211_channel *rx_channel,
 887                           enum nl80211_bss_scan_width scan_width,
 888                           enum cfg80211_bss_frame_type ftype,
 889                           const u8 *bssid, u64 tsf, u16 capability,
 890                           u16 beacon_interval, const u8 *ie, size_t ielen,
 891                           s32 signal, gfp_t gfp)
 892 {
 893         struct cfg80211_bss_ies *ies;
 894         struct ieee80211_channel *channel;
 895         struct cfg80211_internal_bss tmp = {}, *res;
 896         bool signal_valid;
 897
 898         if (WARN_ON(!wiphy))
 899                 return NULL;
 900
 901         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
 902                         (signal < 0 || signal > 100)))
 903                 return NULL;
 904
 905         channel = cfg80211_get_bss_channel(wiphy, ie, ielen, rx_channel);
 906         if (!channel)
 907                 return NULL;
 908
 909         memcpy(tmp.pub.bssid, bssid, ETH_ALEN);
 910         tmp.pub.channel = channel;
 911         tmp.pub.scan_width = scan_width;
 912         tmp.pub.signal = signal;
 913         tmp.pub.beacon_interval = beacon_interval;
 914         tmp.pub.capability = capability;
 915         /*
 916          * If we do not know here whether the IEs are from a Beacon or Probe
 917          * Response frame, we need to pick one of the options and only use it
 918          * with the driver that does not provide the full Beacon/Probe Response
 919          * frame. Use Beacon frame pointer to avoid indicating that this should
 920          * override the IEs pointer should we have received an earlier
 921          * indication of Probe Response data.
 922          */
 923         ies = kzalloc(sizeof(*ies) + ielen, gfp);
 924         if (!ies)
 925                 return NULL;
 926         ies->len = ielen;
 927         ies->tsf = tsf;
 928         ies->from_beacon = false;
 929         memcpy(ies->data, ie, ielen);
 930
 931         switch (ftype) {
 932         case CFG80211_BSS_FTYPE_BEACON:
 933                 ies->from_beacon = true;
 934                 /* fall through to assign */
 935         case CFG80211_BSS_FTYPE_UNKNOWN:
 936                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
 937                 break;
 938         case CFG80211_BSS_FTYPE_PRESP:
 939                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
 940                 break;
 941         }
 942         rcu_assign_pointer(tmp.pub.ies, ies);
 943
 944         signal_valid = abs(rx_channel->center_freq - channel->center_freq) <=
 945                 wiphy->max_adj_channel_rssi_comp;
 946         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
 947         if (!res)
 948                 return NULL;
 949
 950         if (res->pub.capability & WLAN_CAPABILITY_ESS)
 951                 regulatory_hint_found_beacon(wiphy, channel, gfp);
 952
 953         trace_cfg80211_return_bss(&res->pub);
 954         /* cfg80211_bss_update gives us a referenced result */
 955         return &res->pub;
 956 }
 957 EXPORT_SYMBOL(cfg80211_inform_bss_width);
 958
 959 /* Returned bss is reference counted and must be cleaned up appropriately. */
 960 struct cfg80211_bss *
 961 cfg80211_inform_bss_width_frame(struct wiphy *wiphy,
 962                                 struct ieee80211_channel *rx_channel,
 963                                 enum nl80211_bss_scan_width scan_width,
 964                                 struct ieee80211_mgmt *mgmt, size_t len,
 965                                 s32 signal, gfp_t gfp)
 966 {
 967         struct cfg80211_internal_bss tmp = {}, *res;
 968         struct cfg80211_bss_ies *ies;
 969         struct ieee80211_channel *channel;
 970         bool signal_valid;
 971         size_t ielen = len - offsetof(struct ieee80211_mgmt,
 972                                       u.probe_resp.variable);
 973
 974         BUILD_BUG_ON(offsetof(struct ieee80211_mgmt, u.probe_resp.variable) !=
 975                         offsetof(struct ieee80211_mgmt, u.beacon.variable));
 976
 977         trace_cfg80211_inform_bss_width_frame(wiphy, rx_channel, scan_width, mgmt,
 978                                               len, signal);
 979
 980         if (WARN_ON(!mgmt))
 981                 return NULL;
 982
 983         if (WARN_ON(!wiphy))
 984                 return NULL;
 985
 986         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
 987                     (signal < 0 || signal > 100)))
 988                 return NULL;
 989
 990         if (WARN_ON(len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
 991                 return NULL;
 992
 993         channel = cfg80211_get_bss_channel(wiphy, mgmt->u.beacon.variable,
 994                                            ielen, rx_channel);
 995         if (!channel)
 996                 return NULL;
 997
 998         ies = kzalloc(sizeof(*ies) + ielen, gfp);
 999         if (!ies)
1000                 return NULL;
1001         ies->len = ielen;
1002         ies->tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
1003         ies->from_beacon = ieee80211_is_beacon(mgmt->frame_control);
1004         memcpy(ies->data, mgmt->u.probe_resp.variable, ielen);
1005
1006         if (ieee80211_is_probe_resp(mgmt->frame_control))
1007                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1008         else
1009                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1010         rcu_assign_pointer(tmp.pub.ies, ies);
1011
1012         memcpy(tmp.pub.bssid, mgmt->bssid, ETH_ALEN);
1013         tmp.pub.channel = channel;
1014         tmp.pub.scan_width = scan_width;
1015         tmp.pub.signal = signal;
1016         tmp.pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
1017         tmp.pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
1018
1019         signal_valid = abs(rx_channel->center_freq - channel->center_freq) <=
1020                 wiphy->max_adj_channel_rssi_comp;
1021         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1022         if (!res)
1023                 return NULL;
1024
1025         if (res->pub.capability & WLAN_CAPABILITY_ESS)
1026                 regulatory_hint_found_beacon(wiphy, channel, gfp);
1027
1028         trace_cfg80211_return_bss(&res->pub);
1029         /* cfg80211_bss_update gives us a referenced result */
1030         return &res->pub;
1031 }
1032 EXPORT_SYMBOL(cfg80211_inform_bss_width_frame);
1033
1034 void cfg80211_ref_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1035 {
1036         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1037         struct cfg80211_internal_bss *bss;
1038
1039         if (!pub)
1040                 return;
1041
1042         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1043
1044         spin_lock_bh(&rdev->bss_lock);
1045         bss_ref_get(rdev, bss);
1046         spin_unlock_bh(&rdev->bss_lock);
1047 }
1048 EXPORT_SYMBOL(cfg80211_ref_bss);
1049
1050 void cfg80211_put_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1051 {
1052         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1053         struct cfg80211_internal_bss *bss;
1054
1055         if (!pub)
1056                 return;
1057
1058         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1059
1060         spin_lock_bh(&rdev->bss_lock);
1061         bss_ref_put(rdev, bss);
1062         spin_unlock_bh(&rdev->bss_lock);
1063 }
1064 EXPORT_SYMBOL(cfg80211_put_bss);
1065
1066 void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1067 {
1068         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1069         struct cfg80211_internal_bss *bss;
1070
1071         if (WARN_ON(!pub))
1072                 return;
1073
1074         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1075
1076         spin_lock_bh(&rdev->bss_lock);
1077         if (!list_empty(&bss->list)) {
1078                 if (__cfg80211_unlink_bss(rdev, bss))
1079                         rdev->bss_generation++;
1080         }
1081         spin_unlock_bh(&rdev->bss_lock);
1082 }
1083 EXPORT_SYMBOL(cfg80211_unlink_bss);
1084
1085 #ifdef CONFIG_CFG80211_WEXT
1086 static struct cfg80211_registered_device *
1087 cfg80211_get_dev_from_ifindex(struct net *net, int ifindex)
1088 {
1089         struct cfg80211_registered_device *rdev;
1090         struct net_device *dev;
1091
1092         ASSERT_RTNL();
1093
1094         dev = dev_get_by_index(net, ifindex);
1095         if (!dev)
1096                 return ERR_PTR(-ENODEV);
1097         if (dev->ieee80211_ptr)
1098                 rdev = wiphy_to_rdev(dev->ieee80211_ptr->wiphy);
1099         else
1100                 rdev = ERR_PTR(-ENODEV);
1101         dev_put(dev);
1102         return rdev;
1103 }
1104
1105 int cfg80211_wext_siwscan(struct net_device *dev,
1106                           struct iw_request_info *info,
1107                           union iwreq_data *wrqu, char *extra)
1108 {
1109         struct cfg80211_registered_device *rdev;
1110         struct wiphy *wiphy;
1111         struct iw_scan_req *wreq = NULL;
1112         struct cfg80211_scan_request *creq = NULL;
1113         int i, err, n_channels = 0;
1114         enum ieee80211_band band;
1115
1116         if (!netif_running(dev))
1117                 return -ENETDOWN;
1118
1119         if (wrqu->data.length == sizeof(struct iw_scan_req))
1120                 wreq = (struct iw_scan_req *)extra;
1121
1122         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1123
1124         if (IS_ERR(rdev))
1125                 return PTR_ERR(rdev);
1126
1127         if (rdev->scan_req || rdev->scan_msg) {
1128                 err = -EBUSY;
1129                 goto out;
1130         }
1131
1132         wiphy = &rdev->wiphy;
1133
1134         /* Determine number of channels, needed to allocate creq */
1135         if (wreq && wreq->num_channels)
1136                 n_channels = wreq->num_channels;
1137         else
1138                 n_channels = ieee80211_get_num_supported_channels(wiphy);
1139
1140         creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
1141                        n_channels * sizeof(void *),
1142                        GFP_ATOMIC);
1143         if (!creq) {
1144                 err = -ENOMEM;
1145                 goto out;
1146         }
1147
1148         creq->wiphy = wiphy;
1149         creq->wdev = dev->ieee80211_ptr;
1150         /* SSIDs come after channels */
1151         creq->ssids = (void *)&creq->channels[n_channels];
1152         creq->n_channels = n_channels;
1153         creq->n_ssids = 1;
1154         creq->scan_start = jiffies;
1155
1156         /* translate "Scan on frequencies" request */
1157         i = 0;
1158         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
1159                 int j;
1160
1161                 if (!wiphy->bands[band])
1162                         continue;
1163
1164                 for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
1165                         /* ignore disabled channels */
1166                         if (wiphy->bands[band]->channels[j].flags &
1167                                                 IEEE80211_CHAN_DISABLED)
1168                                 continue;
1169
1170                         /* If we have a wireless request structure and the
1171                          * wireless request specifies frequencies, then search
1172                          * for the matching hardware channel.
1173                          */
1174                         if (wreq && wreq->num_channels) {
1175                                 int k;
1176                                 int wiphy_freq = wiphy->bands[band]->channels[j].center_freq;
1177                                 for (k = 0; k < wreq->num_channels; k++) {
1178                                         struct iw_freq *freq =
1179                                                 &wreq->channel_list[k];
1180                                         int wext_freq =
1181                                                 cfg80211_wext_freq(freq);
1182
1183                                         if (wext_freq == wiphy_freq)
1184                                                 goto wext_freq_found;
1185                                 }
1186                                 goto wext_freq_not_found;
1187                         }
1188
1189                 wext_freq_found:
1190                         creq->channels[i] = &wiphy->bands[band]->channels[j];
1191                         i++;
1192                 wext_freq_not_found: ;
1193                 }
1194         }
1195         /* No channels found? */
1196         if (!i) {
1197                 err = -EINVAL;
1198                 goto out;
1199         }
1200
1201         /* Set real number of channels specified in creq->channels[] */
1202         creq->n_channels = i;
1203
1204         /* translate "Scan for SSID" request */
1205         if (wreq) {
1206                 if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
1207                         if (wreq->essid_len > IEEE80211_MAX_SSID_LEN) {
1208                                 err = -EINVAL;
1209                                 goto out;
1210                         }
1211                         memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
1212                         creq->ssids[0].ssid_len = wreq->essid_len;
1213                 }
1214                 if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE)
1215                         creq->n_ssids = 0;
1216         }
1217
1218         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
1219                 if (wiphy->bands[i])
1220                         creq->rates[i] = (1 << wiphy->bands[i]->n_bitrates) - 1;
1221
1222         rdev->scan_req = creq;
1223         err = rdev_scan(rdev, creq);
1224         if (err) {
1225                 rdev->scan_req = NULL;
1226                 /* creq will be freed below */
1227         } else {
1228                 nl80211_send_scan_start(rdev, dev->ieee80211_ptr);
1229                 /* creq now owned by driver */
1230                 creq = NULL;
1231                 dev_hold(dev);
1232         }
1233  out:
1234         kfree(creq);
1235         return err;
1236 }
1237 EXPORT_SYMBOL_GPL(cfg80211_wext_siwscan);
1238
1239 static void ieee80211_scan_add_ies(struct iw_request_info *info,
1240                                    const struct cfg80211_bss_ies *ies,
1241                                    char **current_ev, char *end_buf)
1242 {
1243         const u8 *pos, *end, *next;
1244         struct iw_event iwe;
1245
1246         if (!ies)
1247                 return;
1248
1249         /*
1250          * If needed, fragment the IEs buffer (at IE boundaries) into short
1251          * enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
1252          */
1253         pos = ies->data;
1254         end = pos + ies->len;
1255
1256         while (end - pos > IW_GENERIC_IE_MAX) {
1257                 next = pos + 2 + pos[1];
1258                 while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
1259                         next = next + 2 + next[1];
1260
1261                 memset(&iwe, 0, sizeof(iwe));
1262                 iwe.cmd = IWEVGENIE;
1263                 iwe.u.data.length = next - pos;
1264                 *current_ev = iwe_stream_add_point(info, *current_ev,
1265                                                    end_buf, &iwe,
1266                                                    (void *)pos);
1267
1268                 pos = next;
1269         }
1270
1271         if (end > pos) {
1272                 memset(&iwe, 0, sizeof(iwe));
1273                 iwe.cmd = IWEVGENIE;
1274                 iwe.u.data.length = end - pos;
1275                 *current_ev = iwe_stream_add_point(info, *current_ev,
1276                                                    end_buf, &iwe,
1277                                                    (void *)pos);
1278         }
1279 }
1280
1281 static char *
1282 ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,
1283               struct cfg80211_internal_bss *bss, char *current_ev,
1284               char *end_buf)
1285 {
1286         const struct cfg80211_bss_ies *ies;
1287         struct iw_event iwe;
1288         const u8 *ie;
1289         u8 *buf, *cfg, *p;
1290         int rem, i, sig;
1291         bool ismesh = false;
1292
1293         memset(&iwe, 0, sizeof(iwe));
1294         iwe.cmd = SIOCGIWAP;
1295         iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
1296         memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN);
1297         current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
1298                                           IW_EV_ADDR_LEN);
1299
1300         memset(&iwe, 0, sizeof(iwe));
1301         iwe.cmd = SIOCGIWFREQ;
1302         iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq);
1303         iwe.u.freq.e = 0;
1304         current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
1305                                           IW_EV_FREQ_LEN);
1306
1307         memset(&iwe, 0, sizeof(iwe));
1308         iwe.cmd = SIOCGIWFREQ;
1309         iwe.u.freq.m = bss->pub.channel->center_freq;
1310         iwe.u.freq.e = 6;
1311         current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
1312                                           IW_EV_FREQ_LEN);
1313
1314         if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) {
1315                 memset(&iwe, 0, sizeof(iwe));
1316                 iwe.cmd = IWEVQUAL;
1317                 iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED |
1318                                      IW_QUAL_NOISE_INVALID |
1319                                      IW_QUAL_QUAL_UPDATED;
1320                 switch (wiphy->signal_type) {
1321                 case CFG80211_SIGNAL_TYPE_MBM:
1322                         sig = bss->pub.signal / 100;
1323                         iwe.u.qual.level = sig;
1324                         iwe.u.qual.updated |= IW_QUAL_DBM;
1325                         if (sig < -110)         /* rather bad */
1326                                 sig = -110;
1327                         else if (sig > -40)     /* perfect */
1328                                 sig = -40;
1329                         /* will give a range of 0 .. 70 */
1330                         iwe.u.qual.qual = sig + 110;
1331                         break;
1332                 case CFG80211_SIGNAL_TYPE_UNSPEC:
1333                         iwe.u.qual.level = bss->pub.signal;
1334                         /* will give range 0 .. 100 */
1335                         iwe.u.qual.qual = bss->pub.signal;
1336                         break;
1337                 default:
1338                         /* not reached */
1339                         break;
1340                 }
1341                 current_ev = iwe_stream_add_event(info, current_ev, end_buf,
1342                                                   &iwe, IW_EV_QUAL_LEN);
1343         }
1344
1345         memset(&iwe, 0, sizeof(iwe));
1346         iwe.cmd = SIOCGIWENCODE;
1347         if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY)
1348                 iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
1349         else
1350                 iwe.u.data.flags = IW_ENCODE_DISABLED;
1351         iwe.u.data.length = 0;
1352         current_ev = iwe_stream_add_point(info, current_ev, end_buf,
1353                                           &iwe, "");
1354
1355         rcu_read_lock();
1356         ies = rcu_dereference(bss->pub.ies);
1357         rem = ies->len;
1358         ie = ies->data;
1359
1360         while (rem >= 2) {
1361                 /* invalid data */
1362                 if (ie[1] > rem - 2)
1363                         break;
1364
1365                 switch (ie[0]) {
1366                 case WLAN_EID_SSID:
1367                         memset(&iwe, 0, sizeof(iwe));
1368                         iwe.cmd = SIOCGIWESSID;
1369                         iwe.u.data.length = ie[1];
1370                         iwe.u.data.flags = 1;
1371                         current_ev = iwe_stream_add_point(info, current_ev, end_buf,
1372                                                           &iwe, (u8 *)ie + 2);
1373                         break;
1374                 case WLAN_EID_MESH_ID:
1375                         memset(&iwe, 0, sizeof(iwe));
1376                         iwe.cmd = SIOCGIWESSID;
1377                         iwe.u.data.length = ie[1];
1378                         iwe.u.data.flags = 1;
1379                         current_ev = iwe_stream_add_point(info, current_ev, end_buf,
1380                                                           &iwe, (u8 *)ie + 2);
1381                         break;
1382                 case WLAN_EID_MESH_CONFIG:
1383                         ismesh = true;
1384                         if (ie[1] != sizeof(struct ieee80211_meshconf_ie))
1385                                 break;
1386                         buf = kmalloc(50, GFP_ATOMIC);
1387                         if (!buf)
1388                                 break;
1389                         cfg = (u8 *)ie + 2;
1390                         memset(&iwe, 0, sizeof(iwe));
1391                         iwe.cmd = IWEVCUSTOM;
1392                         sprintf(buf, "Mesh Network Path Selection Protocol ID: "
1393                                 "0x%02X", cfg[0]);
1394                         iwe.u.data.length = strlen(buf);
1395                         current_ev = iwe_stream_add_point(info, current_ev,
1396                                                           end_buf,
1397                                                           &iwe, buf);
1398                         sprintf(buf, "Path Selection Metric ID: 0x%02X",
1399                                 cfg[1]);
1400                         iwe.u.data.length = strlen(buf);
1401                         current_ev = iwe_stream_add_point(info, current_ev,
1402                                                           end_buf,
1403                                                           &iwe, buf);
1404                         sprintf(buf, "Congestion Control Mode ID: 0x%02X",
1405                                 cfg[2]);
1406                         iwe.u.data.length = strlen(buf);
1407                         current_ev = iwe_stream_add_point(info, current_ev,
1408                                                           end_buf,
1409                                                           &iwe, buf);
1410                         sprintf(buf, "Synchronization ID: 0x%02X", cfg[3]);
1411                         iwe.u.data.length = strlen(buf);
1412                         current_ev = iwe_stream_add_point(info, current_ev,
1413                                                           end_buf,
1414                                                           &iwe, buf);
1415                         sprintf(buf, "Authentication ID: 0x%02X", cfg[4]);
1416                         iwe.u.data.length = strlen(buf);
1417                         current_ev = iwe_stream_add_point(info, current_ev,
1418                                                           end_buf,
1419                                                           &iwe, buf);
1420                         sprintf(buf, "Formation Info: 0x%02X", cfg[5]);
1421                         iwe.u.data.length = strlen(buf);
1422                         current_ev = iwe_stream_add_point(info, current_ev,
1423                                                           end_buf,
1424                                                           &iwe, buf);
1425                         sprintf(buf, "Capabilities: 0x%02X", cfg[6]);
1426                         iwe.u.data.length = strlen(buf);
1427                         current_ev = iwe_stream_add_point(info, current_ev,
1428                                                           end_buf,
1429                                                           &iwe, buf);
1430                         kfree(buf);
1431                         break;
1432                 case WLAN_EID_SUPP_RATES:
1433                 case WLAN_EID_EXT_SUPP_RATES:
1434                         /* display all supported rates in readable format */
1435                         p = current_ev + iwe_stream_lcp_len(info);
1436
1437                         memset(&iwe, 0, sizeof(iwe));
1438                         iwe.cmd = SIOCGIWRATE;
1439                         /* Those two flags are ignored... */
1440                         iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;
1441
1442                         for (i = 0; i < ie[1]; i++) {
1443                                 iwe.u.bitrate.value =
1444                                         ((ie[i + 2] & 0x7f) * 500000);
1445                                 p = iwe_stream_add_value(info, current_ev, p,
1446                                                 end_buf, &iwe, IW_EV_PARAM_LEN);
1447                         }
1448                         current_ev = p;
1449                         break;
1450                 }
1451                 rem -= ie[1] + 2;
1452                 ie += ie[1] + 2;
1453         }
1454
1455         if (bss->pub.capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS) ||
1456             ismesh) {
1457                 memset(&iwe, 0, sizeof(iwe));
1458                 iwe.cmd = SIOCGIWMODE;
1459                 if (ismesh)
1460                         iwe.u.mode = IW_MODE_MESH;
1461                 else if (bss->pub.capability & WLAN_CAPABILITY_ESS)
1462                         iwe.u.mode = IW_MODE_MASTER;
1463                 else
1464                         iwe.u.mode = IW_MODE_ADHOC;
1465                 current_ev = iwe_stream_add_event(info, current_ev, end_buf,
1466                                                   &iwe, IW_EV_UINT_LEN);
1467         }
1468
1469         buf = kmalloc(31, GFP_ATOMIC);
1470         if (buf) {
1471                 memset(&iwe, 0, sizeof(iwe));
1472                 iwe.cmd = IWEVCUSTOM;
1473                 sprintf(buf, "tsf=%016llx", (unsigned long long)(ies->tsf));
1474                 iwe.u.data.length = strlen(buf);
1475                 current_ev = iwe_stream_add_point(info, current_ev, end_buf,
1476                                                   &iwe, buf);
1477                 memset(&iwe, 0, sizeof(iwe));
1478                 iwe.cmd = IWEVCUSTOM;
1479                 sprintf(buf, " Last beacon: %ums ago",
1480                         elapsed_jiffies_msecs(bss->ts));
1481                 iwe.u.data.length = strlen(buf);
1482                 current_ev = iwe_stream_add_point(info, current_ev,
1483                                                   end_buf, &iwe, buf);
1484                 kfree(buf);
1485         }
1486
1487         ieee80211_scan_add_ies(info, ies, &current_ev, end_buf);
1488         rcu_read_unlock();
1489
1490         return current_ev;
1491 }
1492
1493
1494 static int ieee80211_scan_results(struct cfg80211_registered_device *rdev,
1495                                   struct iw_request_info *info,
1496                                   char *buf, size_t len)
1497 {
1498         char *current_ev = buf;
1499         char *end_buf = buf + len;
1500         struct cfg80211_internal_bss *bss;
1501
1502         spin_lock_bh(&rdev->bss_lock);
1503         cfg80211_bss_expire(rdev);
1504
1505         list_for_each_entry(bss, &rdev->bss_list, list) {
1506                 if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
1507                         spin_unlock_bh(&rdev->bss_lock);
1508                         return -E2BIG;
1509                 }
1510                 current_ev = ieee80211_bss(&rdev->wiphy, info, bss,
1511                                            current_ev, end_buf);
1512         }
1513         spin_unlock_bh(&rdev->bss_lock);
1514         return current_ev - buf;
1515 }
1516
1517
1518 int cfg80211_wext_giwscan(struct net_device *dev,
1519                           struct iw_request_info *info,
1520                           struct iw_point *data, char *extra)
1521 {
1522         struct cfg80211_registered_device *rdev;
1523         int res;
1524
1525         if (!netif_running(dev))
1526                 return -ENETDOWN;
1527
1528         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1529
1530         if (IS_ERR(rdev))
1531                 return PTR_ERR(rdev);
1532
1533         if (rdev->scan_req || rdev->scan_msg)
1534                 return -EAGAIN;
1535
1536         res = ieee80211_scan_results(rdev, info, extra, data->length);
1537         data->length = 0;
1538         if (res >= 0) {
1539                 data->length = res;
1540                 res = 0;
1541         }
1542
1543         return res;
1544 }
1545 EXPORT_SYMBOL_GPL(cfg80211_wext_giwscan);
1546 #endif