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_printf(MSG_DEBUG, "Already associated with a configured network - "
  48                    "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_printf(MSG_DEBUG, "wpa_supplicant_scan: 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_printf(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_printf(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_printf(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         /* Find the starting point from which to continue scanning */
 311         ssid = wpa_s->conf->ssid;
 312         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
 313                 while (ssid) {
 314                         if (ssid == wpa_s->prev_scan_ssid) {
 315                                 ssid = ssid->next;
 316                                 break;
 317                         }
 318                         ssid = ssid->next;
 319                 }
 320         }
 321
 322         if (scan_req != 2 && (wpa_s->conf->ap_scan == 2 ||
 323                               wpa_s->connect_without_scan)) {
 324                 wpa_s->connect_without_scan = 0;
 325                 wpa_supplicant_assoc_try(wpa_s, ssid);
 326                 return;
 327         } else if (wpa_s->conf->ap_scan == 2) {
 328                 /*
 329                  * User-initiated scan request in ap_scan == 2; scan with
 330                  * wildcard SSID.
 331                  */
 332                 ssid = NULL;
 333         } else {
 334                 struct wpa_ssid *start = ssid, *tssid;
 335                 int freqs_set = 0;
 336                 if (ssid == NULL && max_ssids > 1)
 337                         ssid = wpa_s->conf->ssid;
 338                 while (ssid) {
 339                         if (!ssid->disabled && ssid->scan_ssid) {
 340                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 341                                                   ssid->ssid, ssid->ssid_len);
 342                                 params.ssids[params.num_ssids].ssid =
 343                                         ssid->ssid;
 344                                 params.ssids[params.num_ssids].ssid_len =
 345                                         ssid->ssid_len;
 346                                 params.num_ssids++;
 347                                 if (params.num_ssids + 1 >= max_ssids)
 348                                         break;
 349                         }
 350                         ssid = ssid->next;
 351                         if (ssid == start)
 352                                 break;
 353                         if (ssid == NULL && max_ssids > 1 &&
 354                             start != wpa_s->conf->ssid)
 355                                 ssid = wpa_s->conf->ssid;
 356                 }
 357
 358                 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
 359                         if (tssid->disabled)
 360                                 continue;
 361                         if ((params.freqs || !freqs_set) && tssid->scan_freq) {
 362                                 int_array_concat(&params.freqs,
 363                                                  tssid->scan_freq);
 364                         } else {
 365                                 os_free(params.freqs);
 366                                 params.freqs = NULL;
 367                         }
 368                         freqs_set = 1;
 369                 }
 370                 int_array_sort_unique(params.freqs);
 371         }
 372
 373         if (ssid) {
 374                 wpa_s->prev_scan_ssid = ssid;
 375                 if (max_ssids > 1) {
 376                         wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
 377                                    "scan request");
 378                         params.num_ssids++;
 379                 }
 380                 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
 381         } else {
 382                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 383                 params.num_ssids++;
 384                 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
 385         }
 386
 387 #ifdef CONFIG_P2P
 388         wpa_s->wps->dev.p2p = 1;
 389         if (!wps) {
 390                 wps = 1;
 391                 req_type = WPS_REQ_ENROLLEE_INFO;
 392         }
 393
 394         if (params.freqs == NULL && wpa_s->p2p_in_provisioning &&
 395             wpa_s->go_params) {
 396                 /* Optimize provisioning state scan based on GO information */
 397                 if (wpa_s->p2p_in_provisioning < 5 &&
 398                     wpa_s->go_params->freq > 0) {
 399                         wpa_printf(MSG_DEBUG, "P2P: Scan only GO preferred "
 400                                    "frequency %d MHz",
 401                                    wpa_s->go_params->freq);
 402                         params.freqs = os_zalloc(2 * sizeof(int));
 403                         if (params.freqs)
 404                                 params.freqs[0] = wpa_s->go_params->freq;
 405                 } else if (wpa_s->p2p_in_provisioning < 8 &&
 406                            wpa_s->go_params->freq_list[0]) {
 407                         wpa_printf(MSG_DEBUG, "P2P: Scan only common "
 408                                    "channels");
 409                         int_array_concat(&params.freqs,
 410                                          wpa_s->go_params->freq_list);
 411                         if (params.freqs)
 412                                 int_array_sort_unique(params.freqs);
 413                 }
 414                 wpa_s->p2p_in_provisioning++;
 415         }
 416 #endif /* CONFIG_P2P */
 417
 418 #ifdef CONFIG_WPS
 419         if (params.freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
 420                 /*
 421                  * Optimize post-provisioning scan based on channel used
 422                  * during provisioning.
 423                  */
 424                 wpa_printf(MSG_DEBUG, "WPS: Scan only frequency %u MHz that "
 425                            "was used during provisioning", wpa_s->wps_freq);
 426                 params.freqs = os_zalloc(2 * sizeof(int));
 427                 if (params.freqs)
 428                         params.freqs[0] = wpa_s->wps_freq;
 429                 wpa_s->after_wps--;
 430         }
 431
 432         if (wps) {
 433                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 434                                                 wpa_s->wps->uuid, req_type);
 435                 if (wps_ie) {
 436                         params.extra_ies = wpabuf_head(wps_ie);
 437                         params.extra_ies_len = wpabuf_len(wps_ie);
 438                 }
 439         }
 440 #endif /* CONFIG_WPS */
 441
 442 #ifdef CONFIG_P2P
 443         if (wps_ie) {
 444                 if (wpabuf_resize(&wps_ie, 100) == 0) {
 445                         wpas_p2p_scan_ie(wpa_s, wps_ie);
 446                         params.extra_ies = wpabuf_head(wps_ie);
 447                         params.extra_ies_len = wpabuf_len(wps_ie);
 448                 }
 449         }
 450 #endif /* CONFIG_P2P */
 451
 452         if (params.freqs == NULL && wpa_s->next_scan_freqs) {
 453                 wpa_printf(MSG_DEBUG, "Optimize scan based on previously "
 454                            "generated frequency list");
 455                 params.freqs = wpa_s->next_scan_freqs;
 456         } else
 457                 os_free(wpa_s->next_scan_freqs);
 458         wpa_s->next_scan_freqs = NULL;
 459
 460         params.filter_ssids = wpa_supplicant_build_filter_ssids(
 461                 wpa_s->conf, &params.num_filter_ssids);
 462
 463         ret = wpa_supplicant_trigger_scan(wpa_s, &params);
 464
 465         wpabuf_free(wps_ie);
 466         os_free(params.freqs);
 467         os_free(params.filter_ssids);
 468
 469         if (ret) {
 470                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
 471                 if (prev_state != wpa_s->wpa_state)
 472                         wpa_supplicant_set_state(wpa_s, prev_state);
 473                 wpa_supplicant_req_scan(wpa_s, 1, 0);
 474         }
 475 }
 476
 477
 478 /**
 479  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 480  * @wpa_s: Pointer to wpa_supplicant data
 481  * @sec: Number of seconds after which to scan
 482  * @usec: Number of microseconds after which to scan
 483  *
 484  * This function is used to schedule a scan for neighboring access points after
 485  * the specified time.
 486  */
 487 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 488 {
 489         /* If there's at least one network that should be specifically scanned
 490          * then don't cancel the scan and reschedule.  Some drivers do
 491          * background scanning which generates frequent scan results, and that
 492          * causes the specific SSID scan to get continually pushed back and
 493          * never happen, which causes hidden APs to never get probe-scanned.
 494          */
 495         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 496             wpa_s->conf->ap_scan == 1) {
 497                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 498
 499                 while (ssid) {
 500                         if (!ssid->disabled && ssid->scan_ssid)
 501                                 break;
 502                         ssid = ssid->next;
 503                 }
 504                 if (ssid) {
 505                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 506                                 "ensure that specific SSID scans occur");
 507                         return;
 508                 }
 509         }
 510
 511         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 512                 sec, usec);
 513         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 514         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 515 }
 516
 517
 518 /**
 519  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 520  * @wpa_s: Pointer to wpa_supplicant data
 521  *
 522  * This function is used to cancel a scan request scheduled with
 523  * wpa_supplicant_req_scan().
 524  */
 525 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 526 {
 527         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 528         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 529 }
 530
 531
 532 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
 533                                     int scanning)
 534 {
 535         if (wpa_s->scanning != scanning) {
 536                 wpa_s->scanning = scanning;
 537                 wpas_notify_scanning(wpa_s);
 538         }
 539 }
 540
 541
 542 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
 543 {
 544         int rate = 0;
 545         const u8 *ie;
 546         int i;
 547
 548         ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
 549         for (i = 0; ie && i < ie[1]; i++) {
 550                 if ((ie[i + 2] & 0x7f) > rate)
 551                         rate = ie[i + 2] & 0x7f;
 552         }
 553
 554         ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
 555         for (i = 0; ie && i < ie[1]; i++) {
 556                 if ((ie[i + 2] & 0x7f) > rate)
 557                         rate = ie[i + 2] & 0x7f;
 558         }
 559
 560         return rate;
 561 }
 562
 563
 564 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
 565 {
 566         const u8 *end, *pos;
 567
 568         pos = (const u8 *) (res + 1);
 569         end = pos + res->ie_len;
 570
 571         while (pos + 1 < end) {
 572                 if (pos + 2 + pos[1] > end)
 573                         break;
 574                 if (pos[0] == ie)
 575                         return pos;
 576                 pos += 2 + pos[1];
 577         }
 578
 579         return NULL;
 580 }
 581
 582
 583 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
 584                                   u32 vendor_type)
 585 {
 586         const u8 *end, *pos;
 587
 588         pos = (const u8 *) (res + 1);
 589         end = pos + res->ie_len;
 590
 591         while (pos + 1 < end) {
 592                 if (pos + 2 + pos[1] > end)
 593                         break;
 594                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 595                     vendor_type == WPA_GET_BE32(&pos[2]))
 596                         return pos;
 597                 pos += 2 + pos[1];
 598         }
 599
 600         return NULL;
 601 }
 602
 603
 604 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
 605                                              u32 vendor_type)
 606 {
 607         struct wpabuf *buf;
 608         const u8 *end, *pos;
 609
 610         buf = wpabuf_alloc(res->ie_len);
 611         if (buf == NULL)
 612                 return NULL;
 613
 614         pos = (const u8 *) (res + 1);
 615         end = pos + res->ie_len;
 616
 617         while (pos + 1 < end) {
 618                 if (pos + 2 + pos[1] > end)
 619                         break;
 620                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 621                     vendor_type == WPA_GET_BE32(&pos[2]))
 622                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
 623                 pos += 2 + pos[1];
 624         }
 625
 626         if (wpabuf_len(buf) == 0) {
 627                 wpabuf_free(buf);
 628                 buf = NULL;
 629         }
 630
 631         return buf;
 632 }
 633
 634
 635 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
 636         const struct wpa_scan_res *res, u32 vendor_type)
 637 {
 638         struct wpabuf *buf;
 639         const u8 *end, *pos;
 640
 641         if (res->beacon_ie_len == 0)
 642                 return NULL;
 643         buf = wpabuf_alloc(res->beacon_ie_len);
 644         if (buf == NULL)
 645                 return NULL;
 646
 647         pos = (const u8 *) (res + 1);
 648         pos += res->ie_len;
 649         end = pos + res->beacon_ie_len;
 650
 651         while (pos + 1 < end) {
 652                 if (pos + 2 + pos[1] > end)
 653                         break;
 654                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 655                     vendor_type == WPA_GET_BE32(&pos[2]))
 656                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
 657                 pos += 2 + pos[1];
 658         }
 659
 660         if (wpabuf_len(buf) == 0) {
 661                 wpabuf_free(buf);
 662                 buf = NULL;
 663         }
 664
 665         return buf;
 666 }
 667
 668
 669 /* Compare function for sorting scan results. Return >0 if @b is considered
 670  * better. */
 671 static int wpa_scan_result_compar(const void *a, const void *b)
 672 {
 673         struct wpa_scan_res **_wa = (void *) a;
 674         struct wpa_scan_res **_wb = (void *) b;
 675         struct wpa_scan_res *wa = *_wa;
 676         struct wpa_scan_res *wb = *_wb;
 677         int wpa_a, wpa_b, maxrate_a, maxrate_b;
 678
 679         /* WPA/WPA2 support preferred */
 680         wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
 681                 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
 682         wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
 683                 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
 684
 685         if (wpa_b && !wpa_a)
 686                 return 1;
 687         if (!wpa_b && wpa_a)
 688                 return -1;
 689
 690         /* privacy support preferred */
 691         if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
 692             (wb->caps & IEEE80211_CAP_PRIVACY))
 693                 return 1;
 694         if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
 695             (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
 696                 return -1;
 697
 698         /* best/max rate preferred if signal level close enough XXX */
 699         if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
 700             (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
 701                 maxrate_a = wpa_scan_get_max_rate(wa);
 702                 maxrate_b = wpa_scan_get_max_rate(wb);
 703                 if (maxrate_a != maxrate_b)
 704                         return maxrate_b - maxrate_a;
 705         }
 706
 707         /* use freq for channel preference */
 708
 709         /* all things being equal, use signal level; if signal levels are
 710          * identical, use quality values since some drivers may only report
 711          * that value and leave the signal level zero */
 712         if (wb->level == wa->level)
 713                 return wb->qual - wa->qual;
 714         return wb->level - wa->level;
 715 }
 716
 717
 718 #ifdef CONFIG_WPS
 719 /* Compare function for sorting scan results when searching a WPS AP for
 720  * provisioning. Return >0 if @b is considered better. */
 721 static int wpa_scan_result_wps_compar(const void *a, const void *b)
 722 {
 723         struct wpa_scan_res **_wa = (void *) a;
 724         struct wpa_scan_res **_wb = (void *) b;
 725         struct wpa_scan_res *wa = *_wa;
 726         struct wpa_scan_res *wb = *_wb;
 727         int uses_wps_a, uses_wps_b;
 728         struct wpabuf *wps_a, *wps_b;
 729         int res;
 730
 731         /* Optimization - check WPS IE existence before allocated memory and
 732          * doing full reassembly. */
 733         uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
 734         uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
 735         if (uses_wps_a && !uses_wps_b)
 736                 return -1;
 737         if (!uses_wps_a && uses_wps_b)
 738                 return 1;
 739
 740         if (uses_wps_a && uses_wps_b) {
 741                 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
 742                 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
 743                 res = wps_ap_priority_compar(wps_a, wps_b);
 744                 wpabuf_free(wps_a);
 745                 wpabuf_free(wps_b);
 746                 if (res)
 747                         return res;
 748         }
 749
 750         /*
 751          * Do not use current AP security policy as a sorting criteria during
 752          * WPS provisioning step since the AP may get reconfigured at the
 753          * completion of provisioning.
 754          */
 755
 756         /* all things being equal, use signal level; if signal levels are
 757          * identical, use quality values since some drivers may only report
 758          * that value and leave the signal level zero */
 759         if (wb->level == wa->level)
 760                 return wb->qual - wa->qual;
 761         return wb->level - wa->level;
 762 }
 763 #endif /* CONFIG_WPS */
 764
 765
 766 /**
 767  * wpa_supplicant_get_scan_results - Get scan results
 768  * @wpa_s: Pointer to wpa_supplicant data
 769  * @info: Information about what was scanned or %NULL if not available
 770  * @new_scan: Whether a new scan was performed
 771  * Returns: Scan results, %NULL on failure
 772  *
 773  * This function request the current scan results from the driver and updates
 774  * the local BSS list wpa_s->bss. The caller is responsible for freeing the
 775  * results with wpa_scan_results_free().
 776  */
 777 struct wpa_scan_results *
 778 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
 779                                 struct scan_info *info, int new_scan)
 780 {
 781         struct wpa_scan_results *scan_res;
 782         size_t i;
 783         int (*compar)(const void *, const void *) = wpa_scan_result_compar;
 784
 785         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
 786                 scan_res = ieee80211_sta_get_scan_results(wpa_s);
 787         else
 788                 scan_res = wpa_drv_get_scan_results2(wpa_s);
 789         if (scan_res == NULL) {
 790                 wpa_printf(MSG_DEBUG, "Failed to get scan results");
 791                 return NULL;
 792         }
 793
 794 #ifdef CONFIG_WPS
 795         if (wpas_wps_in_progress(wpa_s)) {
 796                 wpa_printf(MSG_DEBUG, "WPS: Order scan results with WPS "
 797                            "provisioning rules");
 798                 compar = wpa_scan_result_wps_compar;
 799         }
 800 #endif /* CONFIG_WPS */
 801
 802         qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
 803               compar);
 804
 805         wpa_bss_update_start(wpa_s);
 806         for (i = 0; i < scan_res->num; i++)
 807                 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
 808         wpa_bss_update_end(wpa_s, info, new_scan);
 809
 810         return scan_res;
 811 }
 812
 813
 814 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
 815 {
 816         struct wpa_scan_results *scan_res;
 817         scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
 818         if (scan_res == NULL)
 819                 return -1;
 820         wpa_scan_results_free(scan_res);
 821
 822         return 0;
 823 }
 824
 825
 826 void wpa_scan_results_free(struct wpa_scan_results *res)
 827 {
 828         size_t i;
 829
 830         if (res == NULL)
 831                 return;
 832
 833         for (i = 0; i < res->num; i++)
 834                 os_free(res->res[i]);
 835         os_free(res->res);
 836         os_free(res);
 837 }