net/wireless/scan.c

   1 /*
   2  * cfg80211 scan result handling
   3  *
   4  * Copyright 2008 Johannes Berg <johannes@sipsolutions.net>
   5  */
   6 #include <linux/kernel.h>
   7 #include <linux/slab.h>
   8 #include <linux/module.h>
   9 #include <linux/netdevice.h>
  10 #include <linux/wireless.h>
  11 #include <linux/nl80211.h>
  12 #include <linux/etherdevice.h>
  13 #include <net/arp.h>
  14 #include <net/cfg80211.h>
  15 #include <net/cfg80211-wext.h>
  16 #include <net/iw_handler.h>
  17 #include "core.h"
  18 #include "nl80211.h"
  19 #include "wext-compat.h"
  20 #include "rdev-ops.h"
  21
  22 /**
  23  * DOC: BSS tree/list structure
  24  *
  25  * At the top level, the BSS list is kept in both a list in each
  26  * registered device (@bss_list) as well as an RB-tree for faster
  27  * lookup. In the RB-tree, entries can be looked up using their
  28  * channel, MESHID, MESHCONF (for MBSSes) or channel, BSSID, SSID
  29  * for other BSSes.
  30  *
  31  * Due to the possibility of hidden SSIDs, there's a second level
  32  * structure, the "hidden_list" and "hidden_beacon_bss" pointer.
  33  * The hidden_list connects all BSSes belonging to a single AP
  34  * that has a hidden SSID, and connects beacon and probe response
  35  * entries. For a probe response entry for a hidden SSID, the
  36  * hidden_beacon_bss pointer points to the BSS struct holding the
  37  * beacon's information.
  38  *
  39  * Reference counting is done for all these references except for
  40  * the hidden_list, so that a beacon BSS struct that is otherwise
  41  * not referenced has one reference for being on the bss_list and
  42  * one for each probe response entry that points to it using the
  43  * hidden_beacon_bss pointer. When a BSS struct that has such a
  44  * pointer is get/put, the refcount update is also propagated to
  45  * the referenced struct, this ensure that it cannot get removed
  46  * while somebody is using the probe response version.
  47  *
  48  * Note that the hidden_beacon_bss pointer never changes, due to
  49  * the reference counting. Therefore, no locking is needed for
  50  * it.
  51  *
  52  * Also note that the hidden_beacon_bss pointer is only relevant
  53  * if the driver uses something other than the IEs, e.g. private
  54  * data stored stored in the BSS struct, since the beacon IEs are
  55  * also linked into the probe response struct.
  56  */
  57
  58 /*
  59  * Limit the number of BSS entries stored in mac80211. Each one is
  60  * a bit over 4k at most, so this limits to roughly 4-5M of memory.
  61  * If somebody wants to really attack this though, they'd likely
  62  * use small beacons, and only one type of frame, limiting each of
  63  * the entries to a much smaller size (in order to generate more
  64  * entries in total, so overhead is bigger.)
  65  */
  66 static int bss_entries_limit = 1000;
  67 module_param(bss_entries_limit, int, 0644);
  68 MODULE_PARM_DESC(bss_entries_limit,
  69                  "limit to number of scan BSS entries (per wiphy, default 1000)");
  70
  71 #define IEEE80211_SCAN_RESULT_EXPIRE    (30 * HZ)
  72
  73 static void bss_free(struct cfg80211_internal_bss *bss)
  74 {
  75         struct cfg80211_bss_ies *ies;
  76
  77         if (WARN_ON(atomic_read(&bss->hold)))
  78                 return;
  79
  80         ies = (void *)rcu_access_pointer(bss->pub.beacon_ies);
  81         if (ies && !bss->pub.hidden_beacon_bss)
  82                 kfree_rcu(ies, rcu_head);
  83         ies = (void *)rcu_access_pointer(bss->pub.proberesp_ies);
  84         if (ies)
  85                 kfree_rcu(ies, rcu_head);
  86
  87         /*
  88          * This happens when the module is removed, it doesn't
  89          * really matter any more save for completeness
  90          */
  91         if (!list_empty(&bss->hidden_list))
  92                 list_del(&bss->hidden_list);
  93
  94         kfree(bss);
  95 }
  96
  97 static inline void bss_ref_get(struct cfg80211_registered_device *rdev,
  98                                struct cfg80211_internal_bss *bss)
  99 {
 100         lockdep_assert_held(&rdev->bss_lock);
 101
 102         bss->refcount++;
 103         if (bss->pub.hidden_beacon_bss) {
 104                 bss = container_of(bss->pub.hidden_beacon_bss,
 105                                    struct cfg80211_internal_bss,
 106                                    pub);
 107                 bss->refcount++;
 108         }
 109 }
 110
 111 static inline void bss_ref_put(struct cfg80211_registered_device *rdev,
 112                                struct cfg80211_internal_bss *bss)
 113 {
 114         lockdep_assert_held(&rdev->bss_lock);
 115
 116         if (bss->pub.hidden_beacon_bss) {
 117                 struct cfg80211_internal_bss *hbss;
 118                 hbss = container_of(bss->pub.hidden_beacon_bss,
 119                                     struct cfg80211_internal_bss,
 120                                     pub);
 121                 hbss->refcount--;
 122                 if (hbss->refcount == 0)
 123                         bss_free(hbss);
 124         }
 125         bss->refcount--;
 126         if (bss->refcount == 0)
 127                 bss_free(bss);
 128 }
 129
 130 static bool __cfg80211_unlink_bss(struct cfg80211_registered_device *rdev,
 131                                   struct cfg80211_internal_bss *bss)
 132 {
 133         lockdep_assert_held(&rdev->bss_lock);
 134
 135         if (!list_empty(&bss->hidden_list)) {
 136                 /*
 137                  * don't remove the beacon entry if it has
 138                  * probe responses associated with it
 139                  */
 140                 if (!bss->pub.hidden_beacon_bss)
 141                         return false;
 142                 /*
 143                  * if it's a probe response entry break its
 144                  * link to the other entries in the group
 145                  */
 146                 list_del_init(&bss->hidden_list);
 147         }
 148
 149         list_del_init(&bss->list);
 150         rb_erase(&bss->rbn, &rdev->bss_tree);
 151         rdev->bss_entries--;
 152         WARN_ONCE((rdev->bss_entries == 0) ^ list_empty(&rdev->bss_list),
 153                   "rdev bss entries[%d]/list[empty:%d] corruption\n",
 154                   rdev->bss_entries, list_empty(&rdev->bss_list));
 155         bss_ref_put(rdev, bss);
 156         return true;
 157 }
 158
 159 static void __cfg80211_bss_expire(struct cfg80211_registered_device *rdev,
 160                                   unsigned long expire_time)
 161 {
 162         struct cfg80211_internal_bss *bss, *tmp;
 163         bool expired = false;
 164
 165         lockdep_assert_held(&rdev->bss_lock);
 166
 167         list_for_each_entry_safe(bss, tmp, &rdev->bss_list, list) {
 168                 if (atomic_read(&bss->hold))
 169                         continue;
 170                 if (!time_after(expire_time, bss->ts))
 171                         continue;
 172
 173                 if (__cfg80211_unlink_bss(rdev, bss))
 174                         expired = true;
 175         }
 176
 177         if (expired)
 178                 rdev->bss_generation++;
 179 }
 180
 181 static bool cfg80211_bss_expire_oldest(struct cfg80211_registered_device *rdev)
 182 {
 183         struct cfg80211_internal_bss *bss, *oldest = NULL;
 184         bool ret;
 185
 186         lockdep_assert_held(&rdev->bss_lock);
 187
 188         list_for_each_entry(bss, &rdev->bss_list, list) {
 189                 if (atomic_read(&bss->hold))
 190                         continue;
 191
 192                 if (!list_empty(&bss->hidden_list) &&
 193                     !bss->pub.hidden_beacon_bss)
 194                         continue;
 195
 196                 if (oldest && time_before(oldest->ts, bss->ts))
 197                         continue;
 198                 oldest = bss;
 199         }
 200
 201         if (WARN_ON(!oldest))
 202                 return false;
 203
 204         /*
 205          * The callers make sure to increase rdev->bss_generation if anything
 206          * gets removed (and a new entry added), so there's no need to also do
 207          * it here.
 208          */
 209
 210         ret = __cfg80211_unlink_bss(rdev, oldest);
 211         WARN_ON(!ret);
 212         return ret;
 213 }
 214
 215 void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev,
 216                            bool send_message)
 217 {
 218         struct cfg80211_scan_request *request;
 219         struct wireless_dev *wdev;
 220         struct sk_buff *msg;
 221 #ifdef CONFIG_CFG80211_WEXT
 222         union iwreq_data wrqu;
 223 #endif
 224
 225         ASSERT_RTNL();
 226
 227         if (rdev->scan_msg) {
 228                 nl80211_send_scan_result(rdev, rdev->scan_msg);
 229                 rdev->scan_msg = NULL;
 230                 return;
 231         }
 232
 233         request = rdev->scan_req;
 234         if (!request)
 235                 return;
 236
 237         wdev = request->wdev;
 238
 239         /*
 240          * This must be before sending the other events!
 241          * Otherwise, wpa_supplicant gets completely confused with
 242          * wext events.
 243          */
 244         if (wdev->netdev)
 245                 cfg80211_sme_scan_done(wdev->netdev);
 246
 247         if (!request->aborted &&
 248             request->flags & NL80211_SCAN_FLAG_FLUSH) {
 249                 /* flush entries from previous scans */
 250                 spin_lock_bh(&rdev->bss_lock);
 251                 __cfg80211_bss_expire(rdev, request->scan_start);
 252                 spin_unlock_bh(&rdev->bss_lock);
 253         }
 254
 255         msg = nl80211_build_scan_msg(rdev, wdev, request->aborted);
 256
 257 #ifdef CONFIG_CFG80211_WEXT
 258         if (wdev->netdev && !request->aborted) {
 259                 memset(&wrqu, 0, sizeof(wrqu));
 260
 261                 wireless_send_event(wdev->netdev, SIOCGIWSCAN, &wrqu, NULL);
 262         }
 263 #endif
 264
 265         if (wdev->netdev)
 266                 dev_put(wdev->netdev);
 267
 268         rdev->scan_req = NULL;
 269         kfree(request);
 270
 271         if (!send_message)
 272                 rdev->scan_msg = msg;
 273         else
 274                 nl80211_send_scan_result(rdev, msg);
 275 }
 276
 277 void __cfg80211_scan_done(struct work_struct *wk)
 278 {
 279         struct cfg80211_registered_device *rdev;
 280
 281         rdev = container_of(wk, struct cfg80211_registered_device,
 282                             scan_done_wk);
 283
 284         rtnl_lock();
 285         ___cfg80211_scan_done(rdev, true);
 286         rtnl_unlock();
 287 }
 288
 289 void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted)
 290 {
 291         trace_cfg80211_scan_done(request, aborted);
 292         WARN_ON(request != wiphy_to_rdev(request->wiphy)->scan_req);
 293
 294         request->aborted = aborted;
 295         request->notified = true;
 296         queue_work(cfg80211_wq, &wiphy_to_rdev(request->wiphy)->scan_done_wk);
 297 }
 298 EXPORT_SYMBOL(cfg80211_scan_done);
 299
 300 void __cfg80211_sched_scan_results(struct work_struct *wk)
 301 {
 302         struct cfg80211_registered_device *rdev;
 303         struct cfg80211_sched_scan_request *request;
 304
 305         rdev = container_of(wk, struct cfg80211_registered_device,
 306                             sched_scan_results_wk);
 307
 308         rtnl_lock();
 309
 310         request = rdev->sched_scan_req;
 311
 312         /* we don't have sched_scan_req anymore if the scan is stopping */
 313         if (request) {
 314                 if (request->flags & NL80211_SCAN_FLAG_FLUSH) {
 315                         /* flush entries from previous scans */
 316                         spin_lock_bh(&rdev->bss_lock);
 317                         __cfg80211_bss_expire(rdev, request->scan_start);
 318                         spin_unlock_bh(&rdev->bss_lock);
 319                         request->scan_start =
 320                                 jiffies + msecs_to_jiffies(request->interval);
 321                 }
 322                 nl80211_send_sched_scan_results(rdev, request->dev);
 323         }
 324
 325         rtnl_unlock();
 326 }
 327
 328 void cfg80211_sched_scan_results(struct wiphy *wiphy)
 329 {
 330         trace_cfg80211_sched_scan_results(wiphy);
 331         /* ignore if we're not scanning */
 332         if (wiphy_to_rdev(wiphy)->sched_scan_req)
 333                 queue_work(cfg80211_wq,
 334                            &wiphy_to_rdev(wiphy)->sched_scan_results_wk);
 335 }
 336 EXPORT_SYMBOL(cfg80211_sched_scan_results);
 337
 338 void cfg80211_sched_scan_stopped_rtnl(struct wiphy *wiphy)
 339 {
 340         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 341
 342         ASSERT_RTNL();
 343
 344         trace_cfg80211_sched_scan_stopped(wiphy);
 345
 346         __cfg80211_stop_sched_scan(rdev, true);
 347 }
 348 EXPORT_SYMBOL(cfg80211_sched_scan_stopped_rtnl);
 349
 350 void cfg80211_sched_scan_stopped(struct wiphy *wiphy)
 351 {
 352         rtnl_lock();
 353         cfg80211_sched_scan_stopped_rtnl(wiphy);
 354         rtnl_unlock();
 355 }
 356 EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
 357
 358 int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
 359                                bool driver_initiated)
 360 {
 361         struct net_device *dev;
 362
 363         ASSERT_RTNL();
 364
 365         if (!rdev->sched_scan_req)
 366                 return -ENOENT;
 367
 368         dev = rdev->sched_scan_req->dev;
 369
 370         if (!driver_initiated) {
 371                 int err = rdev_sched_scan_stop(rdev, dev);
 372                 if (err)
 373                         return err;
 374         }
 375
 376         nl80211_send_sched_scan(rdev, dev, NL80211_CMD_SCHED_SCAN_STOPPED);
 377
 378         kfree(rdev->sched_scan_req);
 379         rdev->sched_scan_req = NULL;
 380
 381         return 0;
 382 }
 383
 384 void cfg80211_bss_age(struct cfg80211_registered_device *rdev,
 385                       unsigned long age_secs)
 386 {
 387         struct cfg80211_internal_bss *bss;
 388         unsigned long age_jiffies = msecs_to_jiffies(age_secs * MSEC_PER_SEC);
 389
 390         spin_lock_bh(&rdev->bss_lock);
 391         list_for_each_entry(bss, &rdev->bss_list, list)
 392                 bss->ts -= age_jiffies;
 393         spin_unlock_bh(&rdev->bss_lock);
 394 }
 395
 396 void cfg80211_bss_expire(struct cfg80211_registered_device *rdev)
 397 {
 398         __cfg80211_bss_expire(rdev, jiffies - IEEE80211_SCAN_RESULT_EXPIRE);
 399 }
 400
 401 const u8 *cfg80211_find_ie(u8 eid, const u8 *ies, int len)
 402 {
 403         while (len > 2 && ies[0] != eid) {
 404                 len -= ies[1] + 2;
 405                 ies += ies[1] + 2;
 406         }
 407         if (len < 2)
 408                 return NULL;
 409         if (len < 2 + ies[1])
 410                 return NULL;
 411         return ies;
 412 }
 413 EXPORT_SYMBOL(cfg80211_find_ie);
 414
 415 const u8 *cfg80211_find_vendor_ie(unsigned int oui, u8 oui_type,
 416                                   const u8 *ies, int len)
 417 {
 418         struct ieee80211_vendor_ie *ie;
 419         const u8 *pos = ies, *end = ies + len;
 420         int ie_oui;
 421
 422         while (pos < end) {
 423                 pos = cfg80211_find_ie(WLAN_EID_VENDOR_SPECIFIC, pos,
 424                                        end - pos);
 425                 if (!pos)
 426                         return NULL;
 427
 428                 ie = (struct ieee80211_vendor_ie *)pos;
 429
 430                 /* make sure we can access ie->len */
 431                 BUILD_BUG_ON(offsetof(struct ieee80211_vendor_ie, len) != 1);
 432
 433                 if (ie->len < sizeof(*ie))
 434                         goto cont;
 435
 436                 ie_oui = ie->oui[0] << 16 | ie->oui[1] << 8 | ie->oui[2];
 437                 if (ie_oui == oui && ie->oui_type == oui_type)
 438                         return pos;
 439 cont:
 440                 pos += 2 + ie->len;
 441         }
 442         return NULL;
 443 }
 444 EXPORT_SYMBOL(cfg80211_find_vendor_ie);
 445
 446 static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
 447                    const u8 *ssid, size_t ssid_len)
 448 {
 449         const struct cfg80211_bss_ies *ies;
 450         const u8 *ssidie;
 451
 452         if (bssid && !ether_addr_equal(a->bssid, bssid))
 453                 return false;
 454
 455         if (!ssid)
 456                 return true;
 457
 458         ies = rcu_access_pointer(a->ies);
 459         if (!ies)
 460                 return false;
 461         ssidie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 462         if (!ssidie)
 463                 return false;
 464         if (ssidie[1] != ssid_len)
 465                 return false;
 466         return memcmp(ssidie + 2, ssid, ssid_len) == 0;
 467 }
 468
 469 /**
 470  * enum bss_compare_mode - BSS compare mode
 471  * @BSS_CMP_REGULAR: regular compare mode (for insertion and normal find)
 472  * @BSS_CMP_HIDE_ZLEN: find hidden SSID with zero-length mode
 473  * @BSS_CMP_HIDE_NUL: find hidden SSID with NUL-ed out mode
 474  */
 475 enum bss_compare_mode {
 476         BSS_CMP_REGULAR,
 477         BSS_CMP_HIDE_ZLEN,
 478         BSS_CMP_HIDE_NUL,
 479 };
 480
 481 static int cmp_bss(struct cfg80211_bss *a,
 482                    struct cfg80211_bss *b,
 483                    enum bss_compare_mode mode)
 484 {
 485         const struct cfg80211_bss_ies *a_ies, *b_ies;
 486         const u8 *ie1 = NULL;
 487         const u8 *ie2 = NULL;
 488         int i, r;
 489
 490         if (a->channel != b->channel)
 491                 return b->channel->center_freq - a->channel->center_freq;
 492
 493         a_ies = rcu_access_pointer(a->ies);
 494         if (!a_ies)
 495                 return -1;
 496         b_ies = rcu_access_pointer(b->ies);
 497         if (!b_ies)
 498                 return 1;
 499
 500         if (WLAN_CAPABILITY_IS_STA_BSS(a->capability))
 501                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 502                                        a_ies->data, a_ies->len);
 503         if (WLAN_CAPABILITY_IS_STA_BSS(b->capability))
 504                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_ID,
 505                                        b_ies->data, b_ies->len);
 506         if (ie1 && ie2) {
 507                 int mesh_id_cmp;
 508
 509                 if (ie1[1] == ie2[1])
 510                         mesh_id_cmp = memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 511                 else
 512                         mesh_id_cmp = ie2[1] - ie1[1];
 513
 514                 ie1 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 515                                        a_ies->data, a_ies->len);
 516                 ie2 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
 517                                        b_ies->data, b_ies->len);
 518                 if (ie1 && ie2) {
 519                         if (mesh_id_cmp)
 520                                 return mesh_id_cmp;
 521                         if (ie1[1] != ie2[1])
 522                                 return ie2[1] - ie1[1];
 523                         return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 524                 }
 525         }
 526
 527         r = memcmp(a->bssid, b->bssid, sizeof(a->bssid));
 528         if (r)
 529                 return r;
 530
 531         ie1 = cfg80211_find_ie(WLAN_EID_SSID, a_ies->data, a_ies->len);
 532         ie2 = cfg80211_find_ie(WLAN_EID_SSID, b_ies->data, b_ies->len);
 533
 534         if (!ie1 && !ie2)
 535                 return 0;
 536
 537         /*
 538          * Note that with "hide_ssid", the function returns a match if
 539          * the already-present BSS ("b") is a hidden SSID beacon for
 540          * the new BSS ("a").
 541          */
 542
 543         /* sort missing IE before (left of) present IE */
 544         if (!ie1)
 545                 return -1;
 546         if (!ie2)
 547                 return 1;
 548
 549         switch (mode) {
 550         case BSS_CMP_HIDE_ZLEN:
 551                 /*
 552                  * In ZLEN mode we assume the BSS entry we're
 553                  * looking for has a zero-length SSID. So if
 554                  * the one we're looking at right now has that,
 555                  * return 0. Otherwise, return the difference
 556                  * in length, but since we're looking for the
 557                  * 0-length it's really equivalent to returning
 558                  * the length of the one we're looking at.
 559                  *
 560                  * No content comparison is needed as we assume
 561                  * the content length is zero.
 562                  */
 563                 return ie2[1];
 564         case BSS_CMP_REGULAR:
 565         default:
 566                 /* sort by length first, then by contents */
 567                 if (ie1[1] != ie2[1])
 568                         return ie2[1] - ie1[1];
 569                 return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
 570         case BSS_CMP_HIDE_NUL:
 571                 if (ie1[1] != ie2[1])
 572                         return ie2[1] - ie1[1];
 573                 /* this is equivalent to memcmp(zeroes, ie2 + 2, len) */
 574                 for (i = 0; i < ie2[1]; i++)
 575                         if (ie2[i + 2])
 576                                 return -1;
 577                 return 0;
 578         }
 579 }
 580
 581 /* Returned bss is reference counted and must be cleaned up appropriately. */
 582 struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
 583                                       struct ieee80211_channel *channel,
 584                                       const u8 *bssid,
 585                                       const u8 *ssid, size_t ssid_len,
 586                                       u16 capa_mask, u16 capa_val)
 587 {
 588         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 589         struct cfg80211_internal_bss *bss, *res = NULL;
 590         unsigned long now = jiffies;
 591
 592         trace_cfg80211_get_bss(wiphy, channel, bssid, ssid, ssid_len, capa_mask,
 593                                capa_val);
 594
 595         spin_lock_bh(&rdev->bss_lock);
 596
 597         list_for_each_entry(bss, &rdev->bss_list, list) {
 598                 if ((bss->pub.capability & capa_mask) != capa_val)
 599                         continue;
 600                 if (channel && bss->pub.channel != channel)
 601                         continue;
 602                 if (!is_valid_ether_addr(bss->pub.bssid))
 603                         continue;
 604                 /* Don't get expired BSS structs */
 605                 if (time_after(now, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE) &&
 606                     !atomic_read(&bss->hold))
 607                         continue;
 608                 if (is_bss(&bss->pub, bssid, ssid, ssid_len)) {
 609                         res = bss;
 610                         bss_ref_get(rdev, res);
 611                         break;
 612                 }
 613         }
 614
 615         spin_unlock_bh(&rdev->bss_lock);
 616         if (!res)
 617                 return NULL;
 618         trace_cfg80211_return_bss(&res->pub);
 619         return &res->pub;
 620 }
 621 EXPORT_SYMBOL(cfg80211_get_bss);
 622
 623 static void rb_insert_bss(struct cfg80211_registered_device *rdev,
 624                           struct cfg80211_internal_bss *bss)
 625 {
 626         struct rb_node **p = &rdev->bss_tree.rb_node;
 627         struct rb_node *parent = NULL;
 628         struct cfg80211_internal_bss *tbss;
 629         int cmp;
 630
 631         while (*p) {
 632                 parent = *p;
 633                 tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);
 634
 635                 cmp = cmp_bss(&bss->pub, &tbss->pub, BSS_CMP_REGULAR);
 636
 637                 if (WARN_ON(!cmp)) {
 638                         /* will sort of leak this BSS */
 639                         return;
 640                 }
 641
 642                 if (cmp < 0)
 643                         p = &(*p)->rb_left;
 644                 else
 645                         p = &(*p)->rb_right;
 646         }
 647
 648         rb_link_node(&bss->rbn, parent, p);
 649         rb_insert_color(&bss->rbn, &rdev->bss_tree);
 650 }
 651
 652 static struct cfg80211_internal_bss *
 653 rb_find_bss(struct cfg80211_registered_device *rdev,
 654             struct cfg80211_internal_bss *res,
 655             enum bss_compare_mode mode)
 656 {
 657         struct rb_node *n = rdev->bss_tree.rb_node;
 658         struct cfg80211_internal_bss *bss;
 659         int r;
 660
 661         while (n) {
 662                 bss = rb_entry(n, struct cfg80211_internal_bss, rbn);
 663                 r = cmp_bss(&res->pub, &bss->pub, mode);
 664
 665                 if (r == 0)
 666                         return bss;
 667                 else if (r < 0)
 668                         n = n->rb_left;
 669                 else
 670                         n = n->rb_right;
 671         }
 672
 673         return NULL;
 674 }
 675
 676 static bool cfg80211_combine_bsses(struct cfg80211_registered_device *rdev,
 677                                    struct cfg80211_internal_bss *new)
 678 {
 679         const struct cfg80211_bss_ies *ies;
 680         struct cfg80211_internal_bss *bss;
 681         const u8 *ie;
 682         int i, ssidlen;
 683         u8 fold = 0;
 684         u32 n_entries = 0;
 685
 686         ies = rcu_access_pointer(new->pub.beacon_ies);
 687         if (WARN_ON(!ies))
 688                 return false;
 689
 690         ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 691         if (!ie) {
 692                 /* nothing to do */
 693                 return true;
 694         }
 695
 696         ssidlen = ie[1];
 697         for (i = 0; i < ssidlen; i++)
 698                 fold |= ie[2 + i];
 699
 700         if (fold) {
 701                 /* not a hidden SSID */
 702                 return true;
 703         }
 704
 705         /* This is the bad part ... */
 706
 707         list_for_each_entry(bss, &rdev->bss_list, list) {
 708                 /*
 709                  * we're iterating all the entries anyway, so take the
 710                  * opportunity to validate the list length accounting
 711                  */
 712                 n_entries++;
 713
 714                 if (!ether_addr_equal(bss->pub.bssid, new->pub.bssid))
 715                         continue;
 716                 if (bss->pub.channel != new->pub.channel)
 717                         continue;
 718                 if (bss->pub.scan_width != new->pub.scan_width)
 719                         continue;
 720                 if (rcu_access_pointer(bss->pub.beacon_ies))
 721                         continue;
 722                 ies = rcu_access_pointer(bss->pub.ies);
 723                 if (!ies)
 724                         continue;
 725                 ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
 726                 if (!ie)
 727                         continue;
 728                 if (ssidlen && ie[1] != ssidlen)
 729                         continue;
 730                 if (WARN_ON_ONCE(bss->pub.hidden_beacon_bss))
 731                         continue;
 732                 if (WARN_ON_ONCE(!list_empty(&bss->hidden_list)))
 733                         list_del(&bss->hidden_list);
 734                 /* combine them */
 735                 list_add(&bss->hidden_list, &new->hidden_list);
 736                 bss->pub.hidden_beacon_bss = &new->pub;
 737                 new->refcount += bss->refcount;
 738                 rcu_assign_pointer(bss->pub.beacon_ies,
 739                                    new->pub.beacon_ies);
 740         }
 741
 742         WARN_ONCE(n_entries != rdev->bss_entries,
 743                   "rdev bss entries[%d]/list[len:%d] corruption\n",
 744                   rdev->bss_entries, n_entries);
 745
 746         return true;
 747 }
 748
 749 /* Returned bss is reference counted and must be cleaned up appropriately. */
 750 static struct cfg80211_internal_bss *
 751 cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 752                     struct cfg80211_internal_bss *tmp,
 753                     bool signal_valid)
 754 {
 755         struct cfg80211_internal_bss *found = NULL;
 756
 757         if (WARN_ON(!tmp->pub.channel))
 758                 return NULL;
 759
 760         tmp->ts = jiffies;
 761
 762         spin_lock_bh(&rdev->bss_lock);
 763
 764         if (WARN_ON(!rcu_access_pointer(tmp->pub.ies))) {
 765                 spin_unlock_bh(&rdev->bss_lock);
 766                 return NULL;
 767         }
 768
 769         found = rb_find_bss(rdev, tmp, BSS_CMP_REGULAR);
 770
 771         if (found) {
 772                 /* Update IEs */
 773                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
 774                         const struct cfg80211_bss_ies *old;
 775
 776                         old = rcu_access_pointer(found->pub.proberesp_ies);
 777
 778                         rcu_assign_pointer(found->pub.proberesp_ies,
 779                                            tmp->pub.proberesp_ies);
 780                         /* Override possible earlier Beacon frame IEs */
 781                         rcu_assign_pointer(found->pub.ies,
 782                                            tmp->pub.proberesp_ies);
 783                         if (old)
 784                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 785                                           rcu_head);
 786                 } else if (rcu_access_pointer(tmp->pub.beacon_ies)) {
 787                         const struct cfg80211_bss_ies *old;
 788                         struct cfg80211_internal_bss *bss;
 789
 790                         if (found->pub.hidden_beacon_bss &&
 791                             !list_empty(&found->hidden_list)) {
 792                                 const struct cfg80211_bss_ies *f;
 793
 794                                 /*
 795                                  * The found BSS struct is one of the probe
 796                                  * response members of a group, but we're
 797                                  * receiving a beacon (beacon_ies in the tmp
 798                                  * bss is used). This can only mean that the
 799                                  * AP changed its beacon from not having an
 800                                  * SSID to showing it, which is confusing so
 801                                  * drop this information.
 802                                  */
 803
 804                                 f = rcu_access_pointer(tmp->pub.beacon_ies);
 805                                 kfree_rcu((struct cfg80211_bss_ies *)f,
 806                                           rcu_head);
 807                                 goto drop;
 808                         }
 809
 810                         old = rcu_access_pointer(found->pub.beacon_ies);
 811
 812                         rcu_assign_pointer(found->pub.beacon_ies,
 813                                            tmp->pub.beacon_ies);
 814
 815                         /* Override IEs if they were from a beacon before */
 816                         if (old == rcu_access_pointer(found->pub.ies))
 817                                 rcu_assign_pointer(found->pub.ies,
 818                                                    tmp->pub.beacon_ies);
 819
 820                         /* Assign beacon IEs to all sub entries */
 821                         list_for_each_entry(bss, &found->hidden_list,
 822                                             hidden_list) {
 823                                 const struct cfg80211_bss_ies *ies;
 824
 825                                 ies = rcu_access_pointer(bss->pub.beacon_ies);
 826                                 WARN_ON(ies != old);
 827
 828                                 rcu_assign_pointer(bss->pub.beacon_ies,
 829                                                    tmp->pub.beacon_ies);
 830                         }
 831
 832                         if (old)
 833                                 kfree_rcu((struct cfg80211_bss_ies *)old,
 834                                           rcu_head);
 835                 }
 836
 837                 found->pub.beacon_interval = tmp->pub.beacon_interval;
 838                 /*
 839                  * don't update the signal if beacon was heard on
 840                  * adjacent channel.
 841                  */
 842                 if (signal_valid)
 843                         found->pub.signal = tmp->pub.signal;
 844                 found->pub.capability = tmp->pub.capability;
 845                 found->ts = tmp->ts;
 846         } else {
 847                 struct cfg80211_internal_bss *new;
 848                 struct cfg80211_internal_bss *hidden;
 849                 struct cfg80211_bss_ies *ies;
 850
 851                 /*
 852                  * create a copy -- the "res" variable that is passed in
 853                  * is allocated on the stack since it's not needed in the
 854                  * more common case of an update
 855                  */
 856                 new = kzalloc(sizeof(*new) + rdev->wiphy.bss_priv_size,
 857                               GFP_ATOMIC);
 858                 if (!new) {
 859                         ies = (void *)rcu_dereference(tmp->pub.beacon_ies);
 860                         if (ies)
 861                                 kfree_rcu(ies, rcu_head);
 862                         ies = (void *)rcu_dereference(tmp->pub.proberesp_ies);
 863                         if (ies)
 864                                 kfree_rcu(ies, rcu_head);
 865                         goto drop;
 866                 }
 867                 memcpy(new, tmp, sizeof(*new));
 868                 new->refcount = 1;
 869                 INIT_LIST_HEAD(&new->hidden_list);
 870
 871                 if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
 872                         hidden = rb_find_bss(rdev, tmp, BSS_CMP_HIDE_ZLEN);
 873                         if (!hidden)
 874                                 hidden = rb_find_bss(rdev, tmp,
 875                                                      BSS_CMP_HIDE_NUL);
 876                         if (hidden) {
 877                                 new->pub.hidden_beacon_bss = &hidden->pub;
 878                                 list_add(&new->hidden_list,
 879                                          &hidden->hidden_list);
 880                                 hidden->refcount++;
 881                                 rcu_assign_pointer(new->pub.beacon_ies,
 882                                                    hidden->pub.beacon_ies);
 883                         }
 884                 } else {
 885                         /*
 886                          * Ok so we found a beacon, and don't have an entry. If
 887                          * it's a beacon with hidden SSID, we might be in for an
 888                          * expensive search for any probe responses that should
 889                          * be grouped with this beacon for updates ...
 890                          */
 891                         if (!cfg80211_combine_bsses(rdev, new)) {
 892                                 kfree(new);
 893                                 goto drop;
 894                         }
 895                 }
 896
 897                 if (rdev->bss_entries >= bss_entries_limit &&
 898                     !cfg80211_bss_expire_oldest(rdev)) {
 899                         kfree(new);
 900                         goto drop;
 901                 }
 902
 903                 list_add_tail(&new->list, &rdev->bss_list);
 904                 rdev->bss_entries++;
 905                 rb_insert_bss(rdev, new);
 906                 found = new;
 907         }
 908
 909         rdev->bss_generation++;
 910         bss_ref_get(rdev, found);
 911         spin_unlock_bh(&rdev->bss_lock);
 912
 913         return found;
 914  drop:
 915         spin_unlock_bh(&rdev->bss_lock);
 916         return NULL;
 917 }
 918
 919 static struct ieee80211_channel *
 920 cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
 921                          struct ieee80211_channel *channel)
 922 {
 923         const u8 *tmp;
 924         u32 freq;
 925         int channel_number = -1;
 926
 927         tmp = cfg80211_find_ie(WLAN_EID_DS_PARAMS, ie, ielen);
 928         if (tmp && tmp[1] == 1) {
 929                 channel_number = tmp[2];
 930         } else {
 931                 tmp = cfg80211_find_ie(WLAN_EID_HT_OPERATION, ie, ielen);
 932                 if (tmp && tmp[1] >= sizeof(struct ieee80211_ht_operation)) {
 933                         struct ieee80211_ht_operation *htop = (void *)(tmp + 2);
 934
 935                         channel_number = htop->primary_chan;
 936                 }
 937         }
 938
 939         if (channel_number < 0)
 940                 return channel;
 941
 942         freq = ieee80211_channel_to_frequency(channel_number, channel->band);
 943         channel = ieee80211_get_channel(wiphy, freq);
 944         if (!channel)
 945                 return NULL;
 946         if (channel->flags & IEEE80211_CHAN_DISABLED)
 947                 return NULL;
 948         return channel;
 949 }
 950
 951 /* Returned bss is reference counted and must be cleaned up appropriately. */
 952 struct cfg80211_bss*
 953 cfg80211_inform_bss_width(struct wiphy *wiphy,
 954                           struct ieee80211_channel *rx_channel,
 955                           enum nl80211_bss_scan_width scan_width,
 956                           const u8 *bssid, u64 tsf, u16 capability,
 957                           u16 beacon_interval, const u8 *ie, size_t ielen,
 958                           s32 signal, gfp_t gfp)
 959 {
 960         struct cfg80211_bss_ies *ies;
 961         struct ieee80211_channel *channel;
 962         struct cfg80211_internal_bss tmp = {}, *res;
 963         bool signal_valid;
 964
 965         if (WARN_ON(!wiphy))
 966                 return NULL;
 967
 968         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
 969                         (signal < 0 || signal > 100)))
 970                 return NULL;
 971
 972         channel = cfg80211_get_bss_channel(wiphy, ie, ielen, rx_channel);
 973         if (!channel)
 974                 return NULL;
 975
 976         memcpy(tmp.pub.bssid, bssid, ETH_ALEN);
 977         tmp.pub.channel = channel;
 978         tmp.pub.scan_width = scan_width;
 979         tmp.pub.signal = signal;
 980         tmp.pub.beacon_interval = beacon_interval;
 981         tmp.pub.capability = capability;
 982         /*
 983          * Since we do not know here whether the IEs are from a Beacon or Probe
 984          * Response frame, we need to pick one of the options and only use it
 985          * with the driver that does not provide the full Beacon/Probe Response
 986          * frame. Use Beacon frame pointer to avoid indicating that this should
 987          * override the IEs pointer should we have received an earlier
 988          * indication of Probe Response data.
 989          */
 990         ies = kmalloc(sizeof(*ies) + ielen, gfp);
 991         if (!ies)
 992                 return NULL;
 993         ies->len = ielen;
 994         ies->tsf = tsf;
 995         memcpy(ies->data, ie, ielen);
 996
 997         rcu_assign_pointer(tmp.pub.beacon_ies, ies);
 998         rcu_assign_pointer(tmp.pub.ies, ies);
 999
1000         signal_valid = abs(rx_channel->center_freq - channel->center_freq) <=
1001                 wiphy->max_adj_channel_rssi_comp;
1002         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1003         if (!res)
1004                 return NULL;
1005
1006         if (res->pub.capability & WLAN_CAPABILITY_ESS)
1007                 regulatory_hint_found_beacon(wiphy, channel, gfp);
1008
1009         trace_cfg80211_return_bss(&res->pub);
1010         /* cfg80211_bss_update gives us a referenced result */
1011         return &res->pub;
1012 }
1013 EXPORT_SYMBOL(cfg80211_inform_bss_width);
1014
1015 /* Returned bss is reference counted and must be cleaned up appropriately. */
1016 struct cfg80211_bss *
1017 cfg80211_inform_bss_width_frame(struct wiphy *wiphy,
1018                                 struct ieee80211_channel *rx_channel,
1019                                 enum nl80211_bss_scan_width scan_width,
1020                                 struct ieee80211_mgmt *mgmt, size_t len,
1021                                 s32 signal, gfp_t gfp)
1022 {
1023         struct cfg80211_internal_bss tmp = {}, *res;
1024         struct cfg80211_bss_ies *ies;
1025         struct ieee80211_channel *channel;
1026         bool signal_valid;
1027         size_t ielen = len - offsetof(struct ieee80211_mgmt,
1028                                       u.probe_resp.variable);
1029
1030         BUILD_BUG_ON(offsetof(struct ieee80211_mgmt, u.probe_resp.variable) !=
1031                         offsetof(struct ieee80211_mgmt, u.beacon.variable));
1032
1033         trace_cfg80211_inform_bss_width_frame(wiphy, rx_channel, scan_width, mgmt,
1034                                               len, signal);
1035
1036         if (WARN_ON(!mgmt))
1037                 return NULL;
1038
1039         if (WARN_ON(!wiphy))
1040                 return NULL;
1041
1042         if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
1043                     (signal < 0 || signal > 100)))
1044                 return NULL;
1045
1046         if (WARN_ON(len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
1047                 return NULL;
1048
1049         channel = cfg80211_get_bss_channel(wiphy, mgmt->u.beacon.variable,
1050                                            ielen, rx_channel);
1051         if (!channel)
1052                 return NULL;
1053
1054         ies = kmalloc(sizeof(*ies) + ielen, gfp);
1055         if (!ies)
1056                 return NULL;
1057         ies->len = ielen;
1058         ies->tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
1059         memcpy(ies->data, mgmt->u.probe_resp.variable, ielen);
1060
1061         if (ieee80211_is_probe_resp(mgmt->frame_control))
1062                 rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
1063         else
1064                 rcu_assign_pointer(tmp.pub.beacon_ies, ies);
1065         rcu_assign_pointer(tmp.pub.ies, ies);
1066
1067         memcpy(tmp.pub.bssid, mgmt->bssid, ETH_ALEN);
1068         tmp.pub.channel = channel;
1069         tmp.pub.scan_width = scan_width;
1070         tmp.pub.signal = signal;
1071         tmp.pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
1072         tmp.pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
1073
1074         signal_valid = abs(rx_channel->center_freq - channel->center_freq) <=
1075                 wiphy->max_adj_channel_rssi_comp;
1076         res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
1077         if (!res)
1078                 return NULL;
1079
1080         if (res->pub.capability & WLAN_CAPABILITY_ESS)
1081                 regulatory_hint_found_beacon(wiphy, channel, gfp);
1082
1083         trace_cfg80211_return_bss(&res->pub);
1084         /* cfg80211_bss_update gives us a referenced result */
1085         return &res->pub;
1086 }
1087 EXPORT_SYMBOL(cfg80211_inform_bss_width_frame);
1088
1089 void cfg80211_ref_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1090 {
1091         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1092         struct cfg80211_internal_bss *bss;
1093
1094         if (!pub)
1095                 return;
1096
1097         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1098
1099         spin_lock_bh(&rdev->bss_lock);
1100         bss_ref_get(rdev, bss);
1101         spin_unlock_bh(&rdev->bss_lock);
1102 }
1103 EXPORT_SYMBOL(cfg80211_ref_bss);
1104
1105 void cfg80211_put_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1106 {
1107         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1108         struct cfg80211_internal_bss *bss;
1109
1110         if (!pub)
1111                 return;
1112
1113         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1114
1115         spin_lock_bh(&rdev->bss_lock);
1116         bss_ref_put(rdev, bss);
1117         spin_unlock_bh(&rdev->bss_lock);
1118 }
1119 EXPORT_SYMBOL(cfg80211_put_bss);
1120
1121 void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
1122 {
1123         struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
1124         struct cfg80211_internal_bss *bss;
1125
1126         if (WARN_ON(!pub))
1127                 return;
1128
1129         bss = container_of(pub, struct cfg80211_internal_bss, pub);
1130
1131         spin_lock_bh(&rdev->bss_lock);
1132         if (!list_empty(&bss->list)) {
1133                 if (__cfg80211_unlink_bss(rdev, bss))
1134                         rdev->bss_generation++;
1135         }
1136         spin_unlock_bh(&rdev->bss_lock);
1137 }
1138 EXPORT_SYMBOL(cfg80211_unlink_bss);
1139
1140 #ifdef CONFIG_CFG80211_WEXT
1141 static struct cfg80211_registered_device *
1142 cfg80211_get_dev_from_ifindex(struct net *net, int ifindex)
1143 {
1144         struct cfg80211_registered_device *rdev;
1145         struct net_device *dev;
1146
1147         ASSERT_RTNL();
1148
1149         dev = dev_get_by_index(net, ifindex);
1150         if (!dev)
1151                 return ERR_PTR(-ENODEV);
1152         if (dev->ieee80211_ptr)
1153                 rdev = wiphy_to_rdev(dev->ieee80211_ptr->wiphy);
1154         else
1155                 rdev = ERR_PTR(-ENODEV);
1156         dev_put(dev);
1157         return rdev;
1158 }
1159
1160 int cfg80211_wext_siwscan(struct net_device *dev,
1161                           struct iw_request_info *info,
1162                           union iwreq_data *wrqu, char *extra)
1163 {
1164         struct cfg80211_registered_device *rdev;
1165         struct wiphy *wiphy;
1166         struct iw_scan_req *wreq = NULL;
1167         struct cfg80211_scan_request *creq = NULL;
1168         int i, err, n_channels = 0;
1169         enum ieee80211_band band;
1170
1171         if (!netif_running(dev))
1172                 return -ENETDOWN;
1173
1174         if (wrqu->data.length == sizeof(struct iw_scan_req))
1175                 wreq = (struct iw_scan_req *)extra;
1176
1177         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1178
1179         if (IS_ERR(rdev))
1180                 return PTR_ERR(rdev);
1181
1182         if (rdev->scan_req || rdev->scan_msg) {
1183                 err = -EBUSY;
1184                 goto out;
1185         }
1186
1187         wiphy = &rdev->wiphy;
1188
1189         /* Determine number of channels, needed to allocate creq */
1190         if (wreq && wreq->num_channels)
1191                 n_channels = wreq->num_channels;
1192         else
1193                 n_channels = ieee80211_get_num_supported_channels(wiphy);
1194
1195         creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
1196                        n_channels * sizeof(void *),
1197                        GFP_ATOMIC);
1198         if (!creq) {
1199                 err = -ENOMEM;
1200                 goto out;
1201         }
1202
1203         creq->wiphy = wiphy;
1204         creq->wdev = dev->ieee80211_ptr;
1205         /* SSIDs come after channels */
1206         creq->ssids = (void *)&creq->channels[n_channels];
1207         creq->n_channels = n_channels;
1208         creq->n_ssids = 1;
1209         creq->scan_start = jiffies;
1210
1211         /* translate "Scan on frequencies" request */
1212         i = 0;
1213         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
1214                 int j;
1215
1216                 if (!wiphy->bands[band])
1217                         continue;
1218
1219                 for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
1220                         /* ignore disabled channels */
1221                         if (wiphy->bands[band]->channels[j].flags &
1222                                                 IEEE80211_CHAN_DISABLED)
1223                                 continue;
1224
1225                         /* If we have a wireless request structure and the
1226                          * wireless request specifies frequencies, then search
1227                          * for the matching hardware channel.
1228                          */
1229                         if (wreq && wreq->num_channels) {
1230                                 int k;
1231                                 int wiphy_freq = wiphy->bands[band]->channels[j].center_freq;
1232                                 for (k = 0; k < wreq->num_channels; k++) {
1233                                         struct iw_freq *freq =
1234                                                 &wreq->channel_list[k];
1235                                         int wext_freq =
1236                                                 cfg80211_wext_freq(freq);
1237
1238                                         if (wext_freq == wiphy_freq)
1239                                                 goto wext_freq_found;
1240                                 }
1241                                 goto wext_freq_not_found;
1242                         }
1243
1244                 wext_freq_found:
1245                         creq->channels[i] = &wiphy->bands[band]->channels[j];
1246                         i++;
1247                 wext_freq_not_found: ;
1248                 }
1249         }
1250         /* No channels found? */
1251         if (!i) {
1252                 err = -EINVAL;
1253                 goto out;
1254         }
1255
1256         /* Set real number of channels specified in creq->channels[] */
1257         creq->n_channels = i;
1258
1259         /* translate "Scan for SSID" request */
1260         if (wreq) {
1261                 if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
1262                         if (wreq->essid_len > IEEE80211_MAX_SSID_LEN) {
1263                                 err = -EINVAL;
1264                                 goto out;
1265                         }
1266                         memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
1267                         creq->ssids[0].ssid_len = wreq->essid_len;
1268                 }
1269                 if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE)
1270                         creq->n_ssids = 0;
1271         }
1272
1273         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
1274                 if (wiphy->bands[i])
1275                         creq->rates[i] = (1 << wiphy->bands[i]->n_bitrates) - 1;
1276
1277         rdev->scan_req = creq;
1278         err = rdev_scan(rdev, creq);
1279         if (err) {
1280                 rdev->scan_req = NULL;
1281                 /* creq will be freed below */
1282         } else {
1283                 nl80211_send_scan_start(rdev, dev->ieee80211_ptr);
1284                 /* creq now owned by driver */
1285                 creq = NULL;
1286                 dev_hold(dev);
1287         }
1288  out:
1289         kfree(creq);
1290         return err;
1291 }
1292 EXPORT_SYMBOL_GPL(cfg80211_wext_siwscan);
1293
1294 static void ieee80211_scan_add_ies(struct iw_request_info *info,
1295                                    const struct cfg80211_bss_ies *ies,
1296                                    char **current_ev, char *end_buf)
1297 {
1298         const u8 *pos, *end, *next;
1299         struct iw_event iwe;
1300
1301         if (!ies)
1302                 return;
1303
1304         /*
1305          * If needed, fragment the IEs buffer (at IE boundaries) into short
1306          * enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
1307          */
1308         pos = ies->data;
1309         end = pos + ies->len;
1310
1311         while (end - pos > IW_GENERIC_IE_MAX) {
1312                 next = pos + 2 + pos[1];
1313                 while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
1314                         next = next + 2 + next[1];
1315
1316                 memset(&iwe, 0, sizeof(iwe));
1317                 iwe.cmd = IWEVGENIE;
1318                 iwe.u.data.length = next - pos;
1319                 *current_ev = iwe_stream_add_point(info, *current_ev,
1320                                                    end_buf, &iwe,
1321                                                    (void *)pos);
1322
1323                 pos = next;
1324         }
1325
1326         if (end > pos) {
1327                 memset(&iwe, 0, sizeof(iwe));
1328                 iwe.cmd = IWEVGENIE;
1329                 iwe.u.data.length = end - pos;
1330                 *current_ev = iwe_stream_add_point(info, *current_ev,
1331                                                    end_buf, &iwe,
1332                                                    (void *)pos);
1333         }
1334 }
1335
1336 static char *
1337 ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,
1338               struct cfg80211_internal_bss *bss, char *current_ev,
1339               char *end_buf)
1340 {
1341         const struct cfg80211_bss_ies *ies;
1342         struct iw_event iwe;
1343         const u8 *ie;
1344         u8 *buf, *cfg, *p;
1345         int rem, i, sig;
1346         bool ismesh = false;
1347
1348         memset(&iwe, 0, sizeof(iwe));
1349         iwe.cmd = SIOCGIWAP;
1350         iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
1351         memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN);
1352         current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
1353                                           IW_EV_ADDR_LEN);
1354
1355         memset(&iwe, 0, sizeof(iwe));
1356         iwe.cmd = SIOCGIWFREQ;
1357         iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq);
1358         iwe.u.freq.e = 0;
1359         current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
1360                                           IW_EV_FREQ_LEN);
1361
1362         memset(&iwe, 0, sizeof(iwe));
1363         iwe.cmd = SIOCGIWFREQ;
1364         iwe.u.freq.m = bss->pub.channel->center_freq;
1365         iwe.u.freq.e = 6;
1366         current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
1367                                           IW_EV_FREQ_LEN);
1368
1369         if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) {
1370                 memset(&iwe, 0, sizeof(iwe));
1371                 iwe.cmd = IWEVQUAL;
1372                 iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED |
1373                                      IW_QUAL_NOISE_INVALID |
1374                                      IW_QUAL_QUAL_UPDATED;
1375                 switch (wiphy->signal_type) {
1376                 case CFG80211_SIGNAL_TYPE_MBM:
1377                         sig = bss->pub.signal / 100;
1378                         iwe.u.qual.level = sig;
1379                         iwe.u.qual.updated |= IW_QUAL_DBM;
1380                         if (sig < -110)         /* rather bad */
1381                                 sig = -110;
1382                         else if (sig > -40)     /* perfect */
1383                                 sig = -40;
1384                         /* will give a range of 0 .. 70 */
1385                         iwe.u.qual.qual = sig + 110;
1386                         break;
1387                 case CFG80211_SIGNAL_TYPE_UNSPEC:
1388                         iwe.u.qual.level = bss->pub.signal;
1389                         /* will give range 0 .. 100 */
1390                         iwe.u.qual.qual = bss->pub.signal;
1391                         break;
1392                 default:
1393                         /* not reached */
1394                         break;
1395                 }
1396                 current_ev = iwe_stream_add_event(info, current_ev, end_buf,
1397                                                   &iwe, IW_EV_QUAL_LEN);
1398         }
1399
1400         memset(&iwe, 0, sizeof(iwe));
1401         iwe.cmd = SIOCGIWENCODE;
1402         if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY)
1403                 iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
1404         else
1405                 iwe.u.data.flags = IW_ENCODE_DISABLED;
1406         iwe.u.data.length = 0;
1407         current_ev = iwe_stream_add_point(info, current_ev, end_buf,
1408                                           &iwe, "");
1409
1410         rcu_read_lock();
1411         ies = rcu_dereference(bss->pub.ies);
1412         rem = ies->len;
1413         ie = ies->data;
1414
1415         while (rem >= 2) {
1416                 /* invalid data */
1417                 if (ie[1] > rem - 2)
1418                         break;
1419
1420                 switch (ie[0]) {
1421                 case WLAN_EID_SSID:
1422                         memset(&iwe, 0, sizeof(iwe));
1423                         iwe.cmd = SIOCGIWESSID;
1424                         iwe.u.data.length = ie[1];
1425                         iwe.u.data.flags = 1;
1426                         current_ev = iwe_stream_add_point(info, current_ev, end_buf,
1427                                                           &iwe, (u8 *)ie + 2);
1428                         break;
1429                 case WLAN_EID_MESH_ID:
1430                         memset(&iwe, 0, sizeof(iwe));
1431                         iwe.cmd = SIOCGIWESSID;
1432                         iwe.u.data.length = ie[1];
1433                         iwe.u.data.flags = 1;
1434                         current_ev = iwe_stream_add_point(info, current_ev, end_buf,
1435                                                           &iwe, (u8 *)ie + 2);
1436                         break;
1437                 case WLAN_EID_MESH_CONFIG:
1438                         ismesh = true;
1439                         if (ie[1] != sizeof(struct ieee80211_meshconf_ie))
1440                                 break;
1441                         buf = kmalloc(50, GFP_ATOMIC);
1442                         if (!buf)
1443                                 break;
1444                         cfg = (u8 *)ie + 2;
1445                         memset(&iwe, 0, sizeof(iwe));
1446                         iwe.cmd = IWEVCUSTOM;
1447                         sprintf(buf, "Mesh Network Path Selection Protocol ID: "
1448                                 "0x%02X", cfg[0]);
1449                         iwe.u.data.length = strlen(buf);
1450                         current_ev = iwe_stream_add_point(info, current_ev,
1451                                                           end_buf,
1452                                                           &iwe, buf);
1453                         sprintf(buf, "Path Selection Metric ID: 0x%02X",
1454                                 cfg[1]);
1455                         iwe.u.data.length = strlen(buf);
1456                         current_ev = iwe_stream_add_point(info, current_ev,
1457                                                           end_buf,
1458                                                           &iwe, buf);
1459                         sprintf(buf, "Congestion Control Mode ID: 0x%02X",
1460                                 cfg[2]);
1461                         iwe.u.data.length = strlen(buf);
1462                         current_ev = iwe_stream_add_point(info, current_ev,
1463                                                           end_buf,
1464                                                           &iwe, buf);
1465                         sprintf(buf, "Synchronization ID: 0x%02X", cfg[3]);
1466                         iwe.u.data.length = strlen(buf);
1467                         current_ev = iwe_stream_add_point(info, current_ev,
1468                                                           end_buf,
1469                                                           &iwe, buf);
1470                         sprintf(buf, "Authentication ID: 0x%02X", cfg[4]);
1471                         iwe.u.data.length = strlen(buf);
1472                         current_ev = iwe_stream_add_point(info, current_ev,
1473                                                           end_buf,
1474                                                           &iwe, buf);
1475                         sprintf(buf, "Formation Info: 0x%02X", cfg[5]);
1476                         iwe.u.data.length = strlen(buf);
1477                         current_ev = iwe_stream_add_point(info, current_ev,
1478                                                           end_buf,
1479                                                           &iwe, buf);
1480                         sprintf(buf, "Capabilities: 0x%02X", cfg[6]);
1481                         iwe.u.data.length = strlen(buf);
1482                         current_ev = iwe_stream_add_point(info, current_ev,
1483                                                           end_buf,
1484                                                           &iwe, buf);
1485                         kfree(buf);
1486                         break;
1487                 case WLAN_EID_SUPP_RATES:
1488                 case WLAN_EID_EXT_SUPP_RATES:
1489                         /* display all supported rates in readable format */
1490                         p = current_ev + iwe_stream_lcp_len(info);
1491
1492                         memset(&iwe, 0, sizeof(iwe));
1493                         iwe.cmd = SIOCGIWRATE;
1494                         /* Those two flags are ignored... */
1495                         iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;
1496
1497                         for (i = 0; i < ie[1]; i++) {
1498                                 iwe.u.bitrate.value =
1499                                         ((ie[i + 2] & 0x7f) * 500000);
1500                                 p = iwe_stream_add_value(info, current_ev, p,
1501                                                 end_buf, &iwe, IW_EV_PARAM_LEN);
1502                         }
1503                         current_ev = p;
1504                         break;
1505                 }
1506                 rem -= ie[1] + 2;
1507                 ie += ie[1] + 2;
1508         }
1509
1510         if (bss->pub.capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS) ||
1511             ismesh) {
1512                 memset(&iwe, 0, sizeof(iwe));
1513                 iwe.cmd = SIOCGIWMODE;
1514                 if (ismesh)
1515                         iwe.u.mode = IW_MODE_MESH;
1516                 else if (bss->pub.capability & WLAN_CAPABILITY_ESS)
1517                         iwe.u.mode = IW_MODE_MASTER;
1518                 else
1519                         iwe.u.mode = IW_MODE_ADHOC;
1520                 current_ev = iwe_stream_add_event(info, current_ev, end_buf,
1521                                                   &iwe, IW_EV_UINT_LEN);
1522         }
1523
1524         buf = kmalloc(31, GFP_ATOMIC);
1525         if (buf) {
1526                 memset(&iwe, 0, sizeof(iwe));
1527                 iwe.cmd = IWEVCUSTOM;
1528                 sprintf(buf, "tsf=%016llx", (unsigned long long)(ies->tsf));
1529                 iwe.u.data.length = strlen(buf);
1530                 current_ev = iwe_stream_add_point(info, current_ev, end_buf,
1531                                                   &iwe, buf);
1532                 memset(&iwe, 0, sizeof(iwe));
1533                 iwe.cmd = IWEVCUSTOM;
1534                 sprintf(buf, " Last beacon: %ums ago",
1535                         elapsed_jiffies_msecs(bss->ts));
1536                 iwe.u.data.length = strlen(buf);
1537                 current_ev = iwe_stream_add_point(info, current_ev,
1538                                                   end_buf, &iwe, buf);
1539                 kfree(buf);
1540         }
1541
1542         ieee80211_scan_add_ies(info, ies, &current_ev, end_buf);
1543         rcu_read_unlock();
1544
1545         return current_ev;
1546 }
1547
1548
1549 static int ieee80211_scan_results(struct cfg80211_registered_device *rdev,
1550                                   struct iw_request_info *info,
1551                                   char *buf, size_t len)
1552 {
1553         char *current_ev = buf;
1554         char *end_buf = buf + len;
1555         struct cfg80211_internal_bss *bss;
1556
1557         spin_lock_bh(&rdev->bss_lock);
1558         cfg80211_bss_expire(rdev);
1559
1560         list_for_each_entry(bss, &rdev->bss_list, list) {
1561                 if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
1562                         spin_unlock_bh(&rdev->bss_lock);
1563                         return -E2BIG;
1564                 }
1565                 current_ev = ieee80211_bss(&rdev->wiphy, info, bss,
1566                                            current_ev, end_buf);
1567         }
1568         spin_unlock_bh(&rdev->bss_lock);
1569         return current_ev - buf;
1570 }
1571
1572
1573 int cfg80211_wext_giwscan(struct net_device *dev,
1574                           struct iw_request_info *info,
1575                           struct iw_point *data, char *extra)
1576 {
1577         struct cfg80211_registered_device *rdev;
1578         int res;
1579
1580         if (!netif_running(dev))
1581                 return -ENETDOWN;
1582
1583         rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex);
1584
1585         if (IS_ERR(rdev))
1586                 return PTR_ERR(rdev);
1587
1588         if (rdev->scan_req || rdev->scan_msg)
1589                 return -EAGAIN;
1590
1591         res = ieee80211_scan_results(rdev, info, extra, data->length);
1592         data->length = 0;
1593         if (res >= 0) {
1594                 data->length = res;
1595                 res = 0;
1596         }
1597
1598         return res;
1599 }
1600 EXPORT_SYMBOL_GPL(cfg80211_wext_giwscan);
1601 #endif