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         int wps = 0;
 247 #ifdef CONFIG_WPS
 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         if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
 298             !(wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) &&
 299             wps != 2 && !wpa_s->conf->filter_ssids &&
 300             !wpa_s->connect_without_scan) {
 301                 wpa_s->scan_res_tried++;
 302                 wpa_printf(MSG_DEBUG, "Trying to get current scan results "
 303                            "first without requesting a new scan to speed up "
 304                            "initial association");
 305                 wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
 306                 return;
 307         }
 308
 309         scan_req = wpa_s->scan_req;
 310         wpa_s->scan_req = 0;
 311
 312         os_memset(&params, 0, sizeof(params));
 313
 314         prev_state = wpa_s->wpa_state;
 315         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 316             wpa_s->wpa_state == WPA_INACTIVE)
 317                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 318
 319         /* Find the starting point from which to continue scanning */
 320         ssid = wpa_s->conf->ssid;
 321         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
 322                 while (ssid) {
 323                         if (ssid == wpa_s->prev_scan_ssid) {
 324                                 ssid = ssid->next;
 325                                 break;
 326                         }
 327                         ssid = ssid->next;
 328                 }
 329         }
 330
 331         if (scan_req != 2 && (wpa_s->conf->ap_scan == 2 ||
 332                               wpa_s->connect_without_scan)) {
 333                 wpa_s->connect_without_scan = 0;
 334                 wpa_supplicant_assoc_try(wpa_s, ssid);
 335                 return;
 336         } else if (wpa_s->conf->ap_scan == 2) {
 337                 /*
 338                  * User-initiated scan request in ap_scan == 2; scan with
 339                  * wildcard SSID.
 340                  */
 341                 ssid = NULL;
 342         } else {
 343                 struct wpa_ssid *start = ssid, *tssid;
 344                 int freqs_set = 0;
 345                 if (ssid == NULL && max_ssids > 1)
 346                         ssid = wpa_s->conf->ssid;
 347                 while (ssid) {
 348                         if (!ssid->disabled && ssid->scan_ssid) {
 349                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 350                                                   ssid->ssid, ssid->ssid_len);
 351                                 params.ssids[params.num_ssids].ssid =
 352                                         ssid->ssid;
 353                                 params.ssids[params.num_ssids].ssid_len =
 354                                         ssid->ssid_len;
 355                                 params.num_ssids++;
 356                                 if (params.num_ssids + 1 >= max_ssids)
 357                                         break;
 358                         }
 359                         ssid = ssid->next;
 360                         if (ssid == start)
 361                                 break;
 362                         if (ssid == NULL && max_ssids > 1 &&
 363                             start != wpa_s->conf->ssid)
 364                                 ssid = wpa_s->conf->ssid;
 365                 }
 366
 367                 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
 368                         if (tssid->disabled)
 369                                 continue;
 370                         if ((params.freqs || !freqs_set) && tssid->scan_freq) {
 371                                 int_array_concat(&params.freqs,
 372                                                  tssid->scan_freq);
 373                         } else {
 374                                 os_free(params.freqs);
 375                                 params.freqs = NULL;
 376                         }
 377                         freqs_set = 1;
 378                 }
 379                 int_array_sort_unique(params.freqs);
 380         }
 381
 382         if (ssid) {
 383                 wpa_s->prev_scan_ssid = ssid;
 384                 if (max_ssids > 1) {
 385                         wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
 386                                    "scan request");
 387                         params.num_ssids++;
 388                 }
 389                 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
 390         } else {
 391                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 392                 params.num_ssids++;
 393                 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
 394         }
 395
 396 #ifdef CONFIG_WPS
 397         if (params.freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
 398                 /*
 399                  * Optimize post-provisioning scan based on channel used
 400                  * during provisioning.
 401                  */
 402                 wpa_printf(MSG_DEBUG, "WPS: Scan only frequency %u MHz that "
 403                            "was used during provisioning", wpa_s->wps_freq);
 404                 params.freqs = os_zalloc(2 * sizeof(int));
 405                 if (params.freqs)
 406                         params.freqs[0] = wpa_s->wps_freq;
 407                 wpa_s->after_wps--;
 408         }
 409
 410         if (wps) {
 411                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 412                                                 wpa_s->wps->uuid, req_type);
 413                 if (wps_ie) {
 414                         params.extra_ies = wpabuf_head(wps_ie);
 415                         params.extra_ies_len = wpabuf_len(wps_ie);
 416                 }
 417         }
 418 #endif /* CONFIG_WPS */
 419
 420         params.filter_ssids = wpa_supplicant_build_filter_ssids(
 421                 wpa_s->conf, &params.num_filter_ssids);
 422
 423         ret = wpa_supplicant_trigger_scan(wpa_s, &params);
 424
 425         wpabuf_free(wps_ie);
 426         os_free(params.freqs);
 427         os_free(params.filter_ssids);
 428
 429         if (ret) {
 430                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
 431                 if (prev_state != wpa_s->wpa_state)
 432                         wpa_supplicant_set_state(wpa_s, prev_state);
 433                 wpa_supplicant_req_scan(wpa_s, 1, 0);
 434         }
 435 }
 436
 437
 438 /**
 439  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 440  * @wpa_s: Pointer to wpa_supplicant data
 441  * @sec: Number of seconds after which to scan
 442  * @usec: Number of microseconds after which to scan
 443  *
 444  * This function is used to schedule a scan for neighboring access points after
 445  * the specified time.
 446  */
 447 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 448 {
 449         /* If there's at least one network that should be specifically scanned
 450          * then don't cancel the scan and reschedule.  Some drivers do
 451          * background scanning which generates frequent scan results, and that
 452          * causes the specific SSID scan to get continually pushed back and
 453          * never happen, which causes hidden APs to never get probe-scanned.
 454          */
 455         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 456             wpa_s->conf->ap_scan == 1) {
 457                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 458
 459                 while (ssid) {
 460                         if (!ssid->disabled && ssid->scan_ssid)
 461                                 break;
 462                         ssid = ssid->next;
 463                 }
 464                 if (ssid) {
 465                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 466                                 "ensure that specific SSID scans occur");
 467                         return;
 468                 }
 469         }
 470
 471         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 472                 sec, usec);
 473         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 474         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 475 }
 476
 477
 478 /**
 479  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 480  * @wpa_s: Pointer to wpa_supplicant data
 481  *
 482  * This function is used to cancel a scan request scheduled with
 483  * wpa_supplicant_req_scan().
 484  */
 485 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 486 {
 487         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 488         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 489 }
 490
 491
 492 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
 493                                     int scanning)
 494 {
 495         if (wpa_s->scanning != scanning) {
 496                 wpa_s->scanning = scanning;
 497                 wpas_notify_scanning(wpa_s);
 498         }
 499 }
 500
 501
 502 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
 503 {
 504         int rate = 0;
 505         const u8 *ie;
 506         int i;
 507
 508         ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
 509         for (i = 0; ie && i < ie[1]; i++) {
 510                 if ((ie[i + 2] & 0x7f) > rate)
 511                         rate = ie[i + 2] & 0x7f;
 512         }
 513
 514         ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
 515         for (i = 0; ie && i < ie[1]; i++) {
 516                 if ((ie[i + 2] & 0x7f) > rate)
 517                         rate = ie[i + 2] & 0x7f;
 518         }
 519
 520         return rate;
 521 }
 522
 523
 524 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
 525 {
 526         const u8 *end, *pos;
 527
 528         pos = (const u8 *) (res + 1);
 529         end = pos + res->ie_len;
 530
 531         while (pos + 1 < end) {
 532                 if (pos + 2 + pos[1] > end)
 533                         break;
 534                 if (pos[0] == ie)
 535                         return pos;
 536                 pos += 2 + pos[1];
 537         }
 538
 539         return NULL;
 540 }
 541
 542
 543 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
 544                                   u32 vendor_type)
 545 {
 546         const u8 *end, *pos;
 547
 548         pos = (const u8 *) (res + 1);
 549         end = pos + res->ie_len;
 550
 551         while (pos + 1 < end) {
 552                 if (pos + 2 + pos[1] > end)
 553                         break;
 554                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 555                     vendor_type == WPA_GET_BE32(&pos[2]))
 556                         return pos;
 557                 pos += 2 + pos[1];
 558         }
 559
 560         return NULL;
 561 }
 562
 563
 564 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
 565                                              u32 vendor_type)
 566 {
 567         struct wpabuf *buf;
 568         const u8 *end, *pos;
 569
 570         buf = wpabuf_alloc(res->ie_len);
 571         if (buf == NULL)
 572                 return NULL;
 573
 574         pos = (const u8 *) (res + 1);
 575         end = pos + res->ie_len;
 576
 577         while (pos + 1 < end) {
 578                 if (pos + 2 + pos[1] > end)
 579                         break;
 580                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 581                     vendor_type == WPA_GET_BE32(&pos[2]))
 582                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
 583                 pos += 2 + pos[1];
 584         }
 585
 586         if (wpabuf_len(buf) == 0) {
 587                 wpabuf_free(buf);
 588                 buf = NULL;
 589         }
 590
 591         return buf;
 592 }
 593
 594
 595 /* Compare function for sorting scan results. Return >0 if @b is considered
 596  * better. */
 597 static int wpa_scan_result_compar(const void *a, const void *b)
 598 {
 599         struct wpa_scan_res **_wa = (void *) a;
 600         struct wpa_scan_res **_wb = (void *) b;
 601         struct wpa_scan_res *wa = *_wa;
 602         struct wpa_scan_res *wb = *_wb;
 603         int wpa_a, wpa_b, maxrate_a, maxrate_b;
 604
 605         /* WPA/WPA2 support preferred */
 606         wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
 607                 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
 608         wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
 609                 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
 610
 611         if (wpa_b && !wpa_a)
 612                 return 1;
 613         if (!wpa_b && wpa_a)
 614                 return -1;
 615
 616         /* privacy support preferred */
 617         if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
 618             (wb->caps & IEEE80211_CAP_PRIVACY))
 619                 return 1;
 620         if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
 621             (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
 622                 return -1;
 623
 624         /* best/max rate preferred if signal level close enough XXX */
 625         if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
 626             (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
 627                 maxrate_a = wpa_scan_get_max_rate(wa);
 628                 maxrate_b = wpa_scan_get_max_rate(wb);
 629                 if (maxrate_a != maxrate_b)
 630                         return maxrate_b - maxrate_a;
 631         }
 632
 633         /* use freq for channel preference */
 634
 635         /* all things being equal, use signal level; if signal levels are
 636          * identical, use quality values since some drivers may only report
 637          * that value and leave the signal level zero */
 638         if (wb->level == wa->level)
 639                 return wb->qual - wa->qual;
 640         return wb->level - wa->level;
 641 }
 642
 643
 644 #ifdef CONFIG_WPS
 645 /* Compare function for sorting scan results when searching a WPS AP for
 646  * provisioning. Return >0 if @b is considered better. */
 647 static int wpa_scan_result_wps_compar(const void *a, const void *b)
 648 {
 649         struct wpa_scan_res **_wa = (void *) a;
 650         struct wpa_scan_res **_wb = (void *) b;
 651         struct wpa_scan_res *wa = *_wa;
 652         struct wpa_scan_res *wb = *_wb;
 653         int uses_wps_a, uses_wps_b;
 654         struct wpabuf *wps_a, *wps_b;
 655         int res;
 656
 657         /* Optimization - check WPS IE existence before allocated memory and
 658          * doing full reassembly. */
 659         uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
 660         uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
 661         if (uses_wps_a && !uses_wps_b)
 662                 return -1;
 663         if (!uses_wps_a && uses_wps_b)
 664                 return 1;
 665
 666         if (uses_wps_a && uses_wps_b) {
 667                 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
 668                 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
 669                 res = wps_ap_priority_compar(wps_a, wps_b);
 670                 wpabuf_free(wps_a);
 671                 wpabuf_free(wps_b);
 672                 if (res)
 673                         return res;
 674         }
 675
 676         /*
 677          * Do not use current AP security policy as a sorting criteria during
 678          * WPS provisioning step since the AP may get reconfigured at the
 679          * completion of provisioning.
 680          */
 681
 682         /* all things being equal, use signal level; if signal levels are
 683          * identical, use quality values since some drivers may only report
 684          * that value and leave the signal level zero */
 685         if (wb->level == wa->level)
 686                 return wb->qual - wa->qual;
 687         return wb->level - wa->level;
 688 }
 689 #endif /* CONFIG_WPS */
 690
 691
 692 /**
 693  * wpa_supplicant_get_scan_results - Get scan results
 694  * @wpa_s: Pointer to wpa_supplicant data
 695  * @info: Information about what was scanned or %NULL if not available
 696  * @new_scan: Whether a new scan was performed
 697  * Returns: Scan results, %NULL on failure
 698  *
 699  * This function request the current scan results from the driver and updates
 700  * the local BSS list wpa_s->bss. The caller is responsible for freeing the
 701  * results with wpa_scan_results_free().
 702  */
 703 struct wpa_scan_results *
 704 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
 705                                 struct scan_info *info, int new_scan)
 706 {
 707         struct wpa_scan_results *scan_res;
 708         size_t i;
 709         int (*compar)(const void *, const void *) = wpa_scan_result_compar;
 710
 711         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
 712                 scan_res = ieee80211_sta_get_scan_results(wpa_s);
 713         else
 714                 scan_res = wpa_drv_get_scan_results2(wpa_s);
 715         if (scan_res == NULL) {
 716                 wpa_printf(MSG_DEBUG, "Failed to get scan results");
 717                 return NULL;
 718         }
 719
 720 #ifdef CONFIG_WPS
 721         if (wpas_wps_in_progress(wpa_s)) {
 722                 wpa_printf(MSG_DEBUG, "WPS: Order scan results with WPS "
 723                            "provisioning rules");
 724                 compar = wpa_scan_result_wps_compar;
 725         }
 726 #endif /* CONFIG_WPS */
 727
 728         qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
 729               compar);
 730
 731         wpa_bss_update_start(wpa_s);
 732         for (i = 0; i < scan_res->num; i++)
 733                 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
 734         wpa_bss_update_end(wpa_s, info, new_scan);
 735
 736         return scan_res;
 737 }
 738
 739
 740 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
 741 {
 742         struct wpa_scan_results *scan_res;
 743         scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
 744         if (scan_res == NULL)
 745                 return -1;
 746         wpa_scan_results_free(scan_res);
 747
 748         return 0;
 749 }
 750
 751
 752 void wpa_scan_results_free(struct wpa_scan_results *res)
 753 {
 754         size_t i;
 755
 756         if (res == NULL)
 757                 return;
 758
 759         for (i = 0; i < res->num; i++)
 760                 os_free(res->res[i]);
 761         os_free(res->res);
 762         os_free(res);
 763 }