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