wpa_supplicant/scan.c

   1 /*
   2  * WPA Supplicant - Scanning
   3  * Copyright (c) 2003-2010, Jouni Malinen <j@w1.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Alternatively, this software may be distributed under the terms of BSD
  10  * license.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #include "utils/includes.h"
  16
  17 #include "utils/common.h"
  18 #include "utils/eloop.h"
  19 #include "common/ieee802_11_defs.h"
  20 #include "config.h"
  21 #include "wpa_supplicant_i.h"
  22 #include "driver_i.h"
  23 #include "mlme.h"
  24 #include "wps_supplicant.h"
  25 #include "p2p_supplicant.h"
  26 #include "p2p/p2p.h"
  27 #include "notify.h"
  28 #include "bss.h"
  29 #include "scan.h"
  30
  31
  32 static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
  33 {
  34         struct wpa_ssid *ssid;
  35         union wpa_event_data data;
  36
  37         ssid = wpa_supplicant_get_ssid(wpa_s);
  38         if (ssid == NULL)
  39                 return;
  40
  41         if (wpa_s->current_ssid == NULL) {
  42                 wpa_s->current_ssid = ssid;
  43                 if (wpa_s->current_ssid != NULL)
  44                         wpas_notify_network_changed(wpa_s);
  45         }
  46         wpa_supplicant_initiate_eapol(wpa_s);
  47         wpa_dbg(wpa_s, MSG_DEBUG, "Already associated with a configured "
  48                 "network - generating associated event");
  49         os_memset(&data, 0, sizeof(data));
  50         wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);
  51 }
  52
  53
  54 #ifdef CONFIG_WPS
  55 static int wpas_wps_in_use(struct wpa_config *conf,
  56                            enum wps_request_type *req_type)
  57 {
  58         struct wpa_ssid *ssid;
  59         int wps = 0;
  60
  61         for (ssid = conf->ssid; ssid; ssid = ssid->next) {
  62                 if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
  63                         continue;
  64
  65                 wps = 1;
  66                 *req_type = wpas_wps_get_req_type(ssid);
  67                 if (!ssid->eap.phase1)
  68                         continue;
  69
  70                 if (os_strstr(ssid->eap.phase1, "pbc=1"))
  71                         return 2;
  72         }
  73
  74         return wps;
  75 }
  76 #endif /* CONFIG_WPS */
  77
  78
  79 int wpa_supplicant_enabled_networks(struct wpa_config *conf)
  80 {
  81         struct wpa_ssid *ssid = conf->ssid;
  82         int count = 0;
  83         while (ssid) {
  84                 if (!ssid->disabled)
  85                         count++;
  86                 ssid = ssid->next;
  87         }
  88         return count;
  89 }
  90
  91
  92 static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
  93                                      struct wpa_ssid *ssid)
  94 {
  95         while (ssid) {
  96                 if (!ssid->disabled)
  97                         break;
  98                 ssid = ssid->next;
  99         }
 100
 101         /* ap_scan=2 mode - try to associate with each SSID. */
 102         if (ssid == NULL) {
 103                 wpa_dbg(wpa_s, MSG_DEBUG, "wpa_supplicant_assoc_try: Reached "
 104                         "end of scan list - go back to beginning");
 105                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 106                 wpa_supplicant_req_scan(wpa_s, 0, 0);
 107                 return;
 108         }
 109         if (ssid->next) {
 110                 /* Continue from the next SSID on the next attempt. */
 111                 wpa_s->prev_scan_ssid = ssid;
 112         } else {
 113                 /* Start from the beginning of the SSID list. */
 114                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 115         }
 116         wpa_supplicant_associate(wpa_s, NULL, ssid);
 117 }
 118
 119
 120 static int int_array_len(const int *a)
 121 {
 122         int i;
 123         for (i = 0; a && a[i]; i++)
 124                 ;
 125         return i;
 126 }
 127
 128
 129 static void int_array_concat(int **res, const int *a)
 130 {
 131         int reslen, alen, i;
 132         int *n;
 133
 134         reslen = int_array_len(*res);
 135         alen = int_array_len(a);
 136
 137         n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
 138         if (n == NULL) {
 139                 os_free(*res);
 140                 *res = NULL;
 141                 return;
 142         }
 143         for (i = 0; i <= alen; i++)
 144                 n[reslen + i] = a[i];
 145         *res = n;
 146 }
 147
 148
 149 static int freq_cmp(const void *a, const void *b)
 150 {
 151         int _a = *(int *) a;
 152         int _b = *(int *) b;
 153
 154         if (_a == 0)
 155                 return 1;
 156         if (_b == 0)
 157                 return -1;
 158         return _a - _b;
 159 }
 160
 161
 162 static void int_array_sort_unique(int *a)
 163 {
 164         int alen;
 165         int i, j;
 166
 167         if (a == NULL)
 168                 return;
 169
 170         alen = int_array_len(a);
 171         qsort(a, alen, sizeof(int), freq_cmp);
 172
 173         i = 0;
 174         j = 1;
 175         while (a[i] && a[j]) {
 176                 if (a[i] == a[j]) {
 177                         j++;
 178                         continue;
 179                 }
 180                 a[++i] = a[j++];
 181         }
 182         if (a[i])
 183                 i++;
 184         a[i] = 0;
 185 }
 186
 187
 188 int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
 189                                 struct wpa_driver_scan_params *params)
 190 {
 191         int ret;
 192
 193         wpa_supplicant_notify_scanning(wpa_s, 1);
 194
 195         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
 196                 ret = ieee80211_sta_req_scan(wpa_s, params);
 197         else
 198                 ret = wpa_drv_scan(wpa_s, params);
 199
 200         if (ret) {
 201                 wpa_supplicant_notify_scanning(wpa_s, 0);
 202                 wpas_notify_scan_done(wpa_s, 0);
 203         } else
 204                 wpa_s->scan_runs++;
 205
 206         return ret;
 207 }
 208
 209
 210 static struct wpa_driver_scan_filter *
 211 wpa_supplicant_build_filter_ssids(struct wpa_config *conf, size_t *num_ssids)
 212 {
 213         struct wpa_driver_scan_filter *ssids;
 214         struct wpa_ssid *ssid;
 215         size_t count;
 216
 217         *num_ssids = 0;
 218         if (!conf->filter_ssids)
 219                 return NULL;
 220
 221         for (count = 0, ssid = conf->ssid; ssid; ssid = ssid->next) {
 222                 if (ssid->ssid && ssid->ssid_len)
 223                         count++;
 224         }
 225         if (count == 0)
 226                 return NULL;
 227         ssids = os_zalloc(count * sizeof(struct wpa_driver_scan_filter));
 228         if (ssids == NULL)
 229                 return NULL;
 230
 231         for (ssid = conf->ssid; ssid; ssid = ssid->next) {
 232                 if (!ssid->ssid || !ssid->ssid_len)
 233                         continue;
 234                 os_memcpy(ssids[*num_ssids].ssid, ssid->ssid, ssid->ssid_len);
 235                 ssids[*num_ssids].ssid_len = ssid->ssid_len;
 236                 (*num_ssids)++;
 237         }
 238
 239         return ssids;
 240 }
 241
 242
 243 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
 244 {
 245         struct wpa_supplicant *wpa_s = eloop_ctx;
 246         struct wpa_ssid *ssid;
 247         int scan_req = 0, ret;
 248         struct wpabuf *wps_ie = NULL;
 249 #ifdef CONFIG_WPS
 250         int wps = 0;
 251         enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
 252 #endif /* CONFIG_WPS */
 253         struct wpa_driver_scan_params params;
 254         size_t max_ssids;
 255         enum wpa_states prev_state;
 256
 257         if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
 258                 wpa_dbg(wpa_s, MSG_DEBUG, "Skip scan - interface disabled");
 259                 return;
 260         }
 261
 262         if (wpa_s->disconnected && !wpa_s->scan_req) {
 263                 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
 264                 return;
 265         }
 266
 267         if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
 268             !wpa_s->scan_req) {
 269                 wpa_dbg(wpa_s, MSG_DEBUG, "No enabled networks - do not scan");
 270                 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
 271                 return;
 272         }
 273
 274         if (wpa_s->conf->ap_scan != 0 &&
 275             (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
 276                 wpa_dbg(wpa_s, MSG_DEBUG, "Using wired authentication - "
 277                         "overriding ap_scan configuration");
 278                 wpa_s->conf->ap_scan = 0;
 279                 wpas_notify_ap_scan_changed(wpa_s);
 280         }
 281
 282         if (wpa_s->conf->ap_scan == 0) {
 283                 wpa_supplicant_gen_assoc_event(wpa_s);
 284                 return;
 285         }
 286
 287         if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
 288             wpa_s->conf->ap_scan == 2)
 289                 max_ssids = 1;
 290         else {
 291                 max_ssids = wpa_s->max_scan_ssids;
 292                 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
 293                         max_ssids = WPAS_MAX_SCAN_SSIDS;
 294         }
 295
 296 #ifdef CONFIG_WPS
 297         wps = wpas_wps_in_use(wpa_s->conf, &req_type);
 298 #endif /* CONFIG_WPS */
 299
 300         scan_req = wpa_s->scan_req;
 301         wpa_s->scan_req = 0;
 302
 303         os_memset(&params, 0, sizeof(params));
 304
 305         prev_state = wpa_s->wpa_state;
 306         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 307             wpa_s->wpa_state == WPA_INACTIVE)
 308                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 309
 310         if (scan_req != 2 && wpa_s->connect_without_scan) {
 311                 for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
 312                         if (ssid == wpa_s->connect_without_scan)
 313                                 break;
 314                 }
 315                 wpa_s->connect_without_scan = NULL;
 316                 if (ssid) {
 317                         wpa_printf(MSG_DEBUG, "Start a pre-selected network "
 318                                    "without scan step");
 319                         wpa_supplicant_associate(wpa_s, NULL, ssid);
 320                         return;
 321                 }
 322         }
 323
 324         /* Find the starting point from which to continue scanning */
 325         ssid = wpa_s->conf->ssid;
 326         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
 327                 while (ssid) {
 328                         if (ssid == wpa_s->prev_scan_ssid) {
 329                                 ssid = ssid->next;
 330                                 break;
 331                         }
 332                         ssid = ssid->next;
 333                 }
 334         }
 335
 336         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
 337                 wpa_s->connect_without_scan = NULL;
 338                 wpa_supplicant_assoc_try(wpa_s, ssid);
 339                 return;
 340         } else if (wpa_s->conf->ap_scan == 2) {
 341                 /*
 342                  * User-initiated scan request in ap_scan == 2; scan with
 343                  * wildcard SSID.
 344                  */
 345                 ssid = NULL;
 346         } else {
 347                 struct wpa_ssid *start = ssid, *tssid;
 348                 int freqs_set = 0;
 349                 if (ssid == NULL && max_ssids > 1)
 350                         ssid = wpa_s->conf->ssid;
 351                 while (ssid) {
 352                         if (!ssid->disabled && ssid->scan_ssid) {
 353                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 354                                                   ssid->ssid, ssid->ssid_len);
 355                                 params.ssids[params.num_ssids].ssid =
 356                                         ssid->ssid;
 357                                 params.ssids[params.num_ssids].ssid_len =
 358                                         ssid->ssid_len;
 359                                 params.num_ssids++;
 360                                 if (params.num_ssids + 1 >= max_ssids)
 361                                         break;
 362                         }
 363                         ssid = ssid->next;
 364                         if (ssid == start)
 365                                 break;
 366                         if (ssid == NULL && max_ssids > 1 &&
 367                             start != wpa_s->conf->ssid)
 368                                 ssid = wpa_s->conf->ssid;
 369                 }
 370
 371                 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
 372                         if (tssid->disabled)
 373                                 continue;
 374                         if ((params.freqs || !freqs_set) && tssid->scan_freq) {
 375                                 int_array_concat(&params.freqs,
 376                                                  tssid->scan_freq);
 377                         } else {
 378                                 os_free(params.freqs);
 379                                 params.freqs = NULL;
 380                         }
 381                         freqs_set = 1;
 382                 }
 383                 int_array_sort_unique(params.freqs);
 384         }
 385
 386         if (ssid) {
 387                 wpa_s->prev_scan_ssid = ssid;
 388                 if (max_ssids > 1) {
 389                         wpa_dbg(wpa_s, MSG_DEBUG, "Include wildcard SSID in "
 390                                 "the scan request");
 391                         params.num_ssids++;
 392                 }
 393                 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for specific "
 394                         "SSID(s)");
 395         } else {
 396                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 397                 params.num_ssids++;
 398                 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for wildcard "
 399                         "SSID");
 400         }
 401
 402 #ifdef CONFIG_P2P
 403         wpa_s->wps->dev.p2p = 1;
 404         if (!wps) {
 405                 wps = 1;
 406                 req_type = WPS_REQ_ENROLLEE_INFO;
 407         }
 408
 409         if (params.freqs == NULL && wpa_s->p2p_in_provisioning &&
 410             wpa_s->go_params) {
 411                 /* Optimize provisioning state scan based on GO information */
 412                 if (wpa_s->p2p_in_provisioning < 5 &&
 413                     wpa_s->go_params->freq > 0) {
 414                         wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only GO "
 415                                 "preferred frequency %d MHz",
 416                                 wpa_s->go_params->freq);
 417                         params.freqs = os_zalloc(2 * sizeof(int));
 418                         if (params.freqs)
 419                                 params.freqs[0] = wpa_s->go_params->freq;
 420                 } else if (wpa_s->p2p_in_provisioning < 8 &&
 421                            wpa_s->go_params->freq_list[0]) {
 422                         wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only common "
 423                                 "channels");
 424                         int_array_concat(&params.freqs,
 425                                          wpa_s->go_params->freq_list);
 426                         if (params.freqs)
 427                                 int_array_sort_unique(params.freqs);
 428                 }
 429                 wpa_s->p2p_in_provisioning++;
 430         }
 431 #endif /* CONFIG_P2P */
 432
 433 #ifdef CONFIG_WPS
 434         if (params.freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
 435                 /*
 436                  * Optimize post-provisioning scan based on channel used
 437                  * during provisioning.
 438                  */
 439                 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Scan only frequency %u MHz "
 440                         "that was used during provisioning", wpa_s->wps_freq);
 441                 params.freqs = os_zalloc(2 * sizeof(int));
 442                 if (params.freqs)
 443                         params.freqs[0] = wpa_s->wps_freq;
 444                 wpa_s->after_wps--;
 445         }
 446
 447         if (wps) {
 448                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 449                                                 wpa_s->wps->uuid, req_type,
 450                                                 0, NULL);
 451                 if (wps_ie) {
 452                         params.extra_ies = wpabuf_head(wps_ie);
 453                         params.extra_ies_len = wpabuf_len(wps_ie);
 454                 }
 455         }
 456 #endif /* CONFIG_WPS */
 457
 458 #ifdef CONFIG_P2P
 459         if (wps_ie) {
 460                 if (wpabuf_resize(&wps_ie, 100) == 0) {
 461                         wpas_p2p_scan_ie(wpa_s, wps_ie);
 462                         params.extra_ies = wpabuf_head(wps_ie);
 463                         params.extra_ies_len = wpabuf_len(wps_ie);
 464                 }
 465         }
 466 #endif /* CONFIG_P2P */
 467
 468         if (params.freqs == NULL && wpa_s->next_scan_freqs) {
 469                 wpa_dbg(wpa_s, MSG_DEBUG, "Optimize scan based on previously "
 470                         "generated frequency list");
 471                 params.freqs = wpa_s->next_scan_freqs;
 472         } else
 473                 os_free(wpa_s->next_scan_freqs);
 474         wpa_s->next_scan_freqs = NULL;
 475
 476         params.filter_ssids = wpa_supplicant_build_filter_ssids(
 477                 wpa_s->conf, &params.num_filter_ssids);
 478
 479         ret = wpa_supplicant_trigger_scan(wpa_s, &params);
 480
 481         wpabuf_free(wps_ie);
 482         os_free(params.freqs);
 483         os_free(params.filter_ssids);
 484
 485         if (ret) {
 486                 wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate AP scan");
 487                 if (prev_state != wpa_s->wpa_state)
 488                         wpa_supplicant_set_state(wpa_s, prev_state);
 489                 wpa_supplicant_req_scan(wpa_s, 1, 0);
 490         }
 491 }
 492
 493
 494 /**
 495  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 496  * @wpa_s: Pointer to wpa_supplicant data
 497  * @sec: Number of seconds after which to scan
 498  * @usec: Number of microseconds after which to scan
 499  *
 500  * This function is used to schedule a scan for neighboring access points after
 501  * the specified time.
 502  */
 503 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 504 {
 505         /* If there's at least one network that should be specifically scanned
 506          * then don't cancel the scan and reschedule.  Some drivers do
 507          * background scanning which generates frequent scan results, and that
 508          * causes the specific SSID scan to get continually pushed back and
 509          * never happen, which causes hidden APs to never get probe-scanned.
 510          */
 511         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 512             wpa_s->conf->ap_scan == 1) {
 513                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 514
 515                 while (ssid) {
 516                         if (!ssid->disabled && ssid->scan_ssid)
 517                                 break;
 518                         ssid = ssid->next;
 519                 }
 520                 if (ssid) {
 521                         wpa_dbg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 522                                 "ensure that specific SSID scans occur");
 523                         return;
 524                 }
 525         }
 526
 527         wpa_dbg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 528                 sec, usec);
 529         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 530         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 531 }
 532
 533
 534 /**
 535  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 536  * @wpa_s: Pointer to wpa_supplicant data
 537  *
 538  * This function is used to cancel a scan request scheduled with
 539  * wpa_supplicant_req_scan().
 540  */
 541 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 542 {
 543         wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 544         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 545         wpa_supplicant_notify_scanning(wpa_s, 0);
 546 }
 547
 548
 549 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
 550                                     int scanning)
 551 {
 552         if (wpa_s->scanning != scanning) {
 553                 wpa_s->scanning = scanning;
 554                 wpas_notify_scanning(wpa_s);
 555         }
 556 }
 557
 558
 559 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
 560 {
 561         int rate = 0;
 562         const u8 *ie;
 563         int i;
 564
 565         ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
 566         for (i = 0; ie && i < ie[1]; i++) {
 567                 if ((ie[i + 2] & 0x7f) > rate)
 568                         rate = ie[i + 2] & 0x7f;
 569         }
 570
 571         ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
 572         for (i = 0; ie && i < ie[1]; i++) {
 573                 if ((ie[i + 2] & 0x7f) > rate)
 574                         rate = ie[i + 2] & 0x7f;
 575         }
 576
 577         return rate;
 578 }
 579
 580
 581 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
 582 {
 583         const u8 *end, *pos;
 584
 585         pos = (const u8 *) (res + 1);
 586         end = pos + res->ie_len;
 587
 588         while (pos + 1 < end) {
 589                 if (pos + 2 + pos[1] > end)
 590                         break;
 591                 if (pos[0] == ie)
 592                         return pos;
 593                 pos += 2 + pos[1];
 594         }
 595
 596         return NULL;
 597 }
 598
 599
 600 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
 601                                   u32 vendor_type)
 602 {
 603         const u8 *end, *pos;
 604
 605         pos = (const u8 *) (res + 1);
 606         end = pos + res->ie_len;
 607
 608         while (pos + 1 < end) {
 609                 if (pos + 2 + pos[1] > end)
 610                         break;
 611                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 612                     vendor_type == WPA_GET_BE32(&pos[2]))
 613                         return pos;
 614                 pos += 2 + pos[1];
 615         }
 616
 617         return NULL;
 618 }
 619
 620
 621 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
 622                                              u32 vendor_type)
 623 {
 624         struct wpabuf *buf;
 625         const u8 *end, *pos;
 626
 627         buf = wpabuf_alloc(res->ie_len);
 628         if (buf == NULL)
 629                 return NULL;
 630
 631         pos = (const u8 *) (res + 1);
 632         end = pos + res->ie_len;
 633
 634         while (pos + 1 < end) {
 635                 if (pos + 2 + pos[1] > end)
 636                         break;
 637                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 638                     vendor_type == WPA_GET_BE32(&pos[2]))
 639                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
 640                 pos += 2 + pos[1];
 641         }
 642
 643         if (wpabuf_len(buf) == 0) {
 644                 wpabuf_free(buf);
 645                 buf = NULL;
 646         }
 647
 648         return buf;
 649 }
 650
 651
 652 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
 653         const struct wpa_scan_res *res, u32 vendor_type)
 654 {
 655         struct wpabuf *buf;
 656         const u8 *end, *pos;
 657
 658         if (res->beacon_ie_len == 0)
 659                 return NULL;
 660         buf = wpabuf_alloc(res->beacon_ie_len);
 661         if (buf == NULL)
 662                 return NULL;
 663
 664         pos = (const u8 *) (res + 1);
 665         pos += res->ie_len;
 666         end = pos + res->beacon_ie_len;
 667
 668         while (pos + 1 < end) {
 669                 if (pos + 2 + pos[1] > end)
 670                         break;
 671                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 672                     vendor_type == WPA_GET_BE32(&pos[2]))
 673                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
 674                 pos += 2 + pos[1];
 675         }
 676
 677         if (wpabuf_len(buf) == 0) {
 678                 wpabuf_free(buf);
 679                 buf = NULL;
 680         }
 681
 682         return buf;
 683 }
 684
 685
 686 /* Compare function for sorting scan results. Return >0 if @b is considered
 687  * better. */
 688 static int wpa_scan_result_compar(const void *a, const void *b)
 689 {
 690         struct wpa_scan_res **_wa = (void *) a;
 691         struct wpa_scan_res **_wb = (void *) b;
 692         struct wpa_scan_res *wa = *_wa;
 693         struct wpa_scan_res *wb = *_wb;
 694         int wpa_a, wpa_b, maxrate_a, maxrate_b;
 695
 696         /* WPA/WPA2 support preferred */
 697         wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
 698                 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
 699         wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
 700                 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
 701
 702         if (wpa_b && !wpa_a)
 703                 return 1;
 704         if (!wpa_b && wpa_a)
 705                 return -1;
 706
 707         /* privacy support preferred */
 708         if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
 709             (wb->caps & IEEE80211_CAP_PRIVACY))
 710                 return 1;
 711         if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
 712             (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
 713                 return -1;
 714
 715         /* best/max rate preferred if signal level close enough XXX */
 716         if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
 717             (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
 718                 maxrate_a = wpa_scan_get_max_rate(wa);
 719                 maxrate_b = wpa_scan_get_max_rate(wb);
 720                 if (maxrate_a != maxrate_b)
 721                         return maxrate_b - maxrate_a;
 722         }
 723
 724         /* use freq for channel preference */
 725
 726         /* all things being equal, use signal level; if signal levels are
 727          * identical, use quality values since some drivers may only report
 728          * that value and leave the signal level zero */
 729         if (wb->level == wa->level)
 730                 return wb->qual - wa->qual;
 731         return wb->level - wa->level;
 732 }
 733
 734
 735 #ifdef CONFIG_WPS
 736 /* Compare function for sorting scan results when searching a WPS AP for
 737  * provisioning. Return >0 if @b is considered better. */
 738 static int wpa_scan_result_wps_compar(const void *a, const void *b)
 739 {
 740         struct wpa_scan_res **_wa = (void *) a;
 741         struct wpa_scan_res **_wb = (void *) b;
 742         struct wpa_scan_res *wa = *_wa;
 743         struct wpa_scan_res *wb = *_wb;
 744         int uses_wps_a, uses_wps_b;
 745         struct wpabuf *wps_a, *wps_b;
 746         int res;
 747
 748         /* Optimization - check WPS IE existence before allocated memory and
 749          * doing full reassembly. */
 750         uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
 751         uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
 752         if (uses_wps_a && !uses_wps_b)
 753                 return -1;
 754         if (!uses_wps_a && uses_wps_b)
 755                 return 1;
 756
 757         if (uses_wps_a && uses_wps_b) {
 758                 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
 759                 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
 760                 res = wps_ap_priority_compar(wps_a, wps_b);
 761                 wpabuf_free(wps_a);
 762                 wpabuf_free(wps_b);
 763                 if (res)
 764                         return res;
 765         }
 766
 767         /*
 768          * Do not use current AP security policy as a sorting criteria during
 769          * WPS provisioning step since the AP may get reconfigured at the
 770          * completion of provisioning.
 771          */
 772
 773         /* all things being equal, use signal level; if signal levels are
 774          * identical, use quality values since some drivers may only report
 775          * that value and leave the signal level zero */
 776         if (wb->level == wa->level)
 777                 return wb->qual - wa->qual;
 778         return wb->level - wa->level;
 779 }
 780 #endif /* CONFIG_WPS */
 781
 782
 783 /**
 784  * wpa_supplicant_get_scan_results - Get scan results
 785  * @wpa_s: Pointer to wpa_supplicant data
 786  * @info: Information about what was scanned or %NULL if not available
 787  * @new_scan: Whether a new scan was performed
 788  * Returns: Scan results, %NULL on failure
 789  *
 790  * This function request the current scan results from the driver and updates
 791  * the local BSS list wpa_s->bss. The caller is responsible for freeing the
 792  * results with wpa_scan_results_free().
 793  */
 794 struct wpa_scan_results *
 795 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
 796                                 struct scan_info *info, int new_scan)
 797 {
 798         struct wpa_scan_results *scan_res;
 799         size_t i;
 800         int (*compar)(const void *, const void *) = wpa_scan_result_compar;
 801
 802         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
 803                 scan_res = ieee80211_sta_get_scan_results(wpa_s);
 804         else
 805                 scan_res = wpa_drv_get_scan_results2(wpa_s);
 806         if (scan_res == NULL) {
 807                 wpa_dbg(wpa_s, MSG_DEBUG, "Failed to get scan results");
 808                 return NULL;
 809         }
 810
 811 #ifdef CONFIG_WPS
 812         if (wpas_wps_in_progress(wpa_s)) {
 813                 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Order scan results with WPS "
 814                         "provisioning rules");
 815                 compar = wpa_scan_result_wps_compar;
 816         }
 817 #endif /* CONFIG_WPS */
 818
 819         qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
 820               compar);
 821
 822         wpa_bss_update_start(wpa_s);
 823         for (i = 0; i < scan_res->num; i++)
 824                 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
 825         wpa_bss_update_end(wpa_s, info, new_scan);
 826
 827         return scan_res;
 828 }
 829
 830
 831 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
 832 {
 833         struct wpa_scan_results *scan_res;
 834         scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
 835         if (scan_res == NULL)
 836                 return -1;
 837         wpa_scan_results_free(scan_res);
 838
 839         return 0;
 840 }
 841
 842
 843 void wpa_scan_results_free(struct wpa_scan_results *res)
 844 {
 845         size_t i;
 846
 847         if (res == NULL)
 848                 return;
 849
 850         for (i = 0; i < res->num; i++)
 851                 os_free(res->res[i]);
 852         os_free(res->res);
 853         os_free(res);
 854 }