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 #ifdef CONFIG_P2P
 288         if (wpas_p2p_in_progress(wpa_s)) {
 289                 if (wpa_s->wpa_state == WPA_SCANNING) {
 290                         wpa_dbg(wpa_s, MSG_DEBUG, "Delay station mode scan "
 291                                 "while P2P operation is in progress");
 292                         wpa_supplicant_req_scan(wpa_s, 5, 0);
 293                 } else {
 294                         wpa_dbg(wpa_s, MSG_DEBUG, "Do not request scan while "
 295                                 "P2P operation is in progress");
 296                 }
 297                 return;
 298         }
 299 #endif /* CONFIG_P2P */
 300
 301         if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
 302             wpa_s->conf->ap_scan == 2)
 303                 max_ssids = 1;
 304         else {
 305                 max_ssids = wpa_s->max_scan_ssids;
 306                 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
 307                         max_ssids = WPAS_MAX_SCAN_SSIDS;
 308         }
 309
 310 #ifdef CONFIG_WPS
 311         wps = wpas_wps_in_use(wpa_s->conf, &req_type);
 312 #endif /* CONFIG_WPS */
 313
 314         scan_req = wpa_s->scan_req;
 315         wpa_s->scan_req = 0;
 316
 317         os_memset(&params, 0, sizeof(params));
 318
 319         prev_state = wpa_s->wpa_state;
 320         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 321             wpa_s->wpa_state == WPA_INACTIVE)
 322                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 323
 324         if (scan_req != 2 && wpa_s->connect_without_scan) {
 325                 for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
 326                         if (ssid == wpa_s->connect_without_scan)
 327                                 break;
 328                 }
 329                 wpa_s->connect_without_scan = NULL;
 330                 if (ssid) {
 331                         wpa_printf(MSG_DEBUG, "Start a pre-selected network "
 332                                    "without scan step");
 333                         wpa_supplicant_associate(wpa_s, NULL, ssid);
 334                         return;
 335                 }
 336         }
 337
 338         /* Find the starting point from which to continue scanning */
 339         ssid = wpa_s->conf->ssid;
 340         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
 341                 while (ssid) {
 342                         if (ssid == wpa_s->prev_scan_ssid) {
 343                                 ssid = ssid->next;
 344                                 break;
 345                         }
 346                         ssid = ssid->next;
 347                 }
 348         }
 349
 350         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
 351                 wpa_s->connect_without_scan = NULL;
 352                 wpa_supplicant_assoc_try(wpa_s, ssid);
 353                 return;
 354         } else if (wpa_s->conf->ap_scan == 2) {
 355                 /*
 356                  * User-initiated scan request in ap_scan == 2; scan with
 357                  * wildcard SSID.
 358                  */
 359                 ssid = NULL;
 360         } else {
 361                 struct wpa_ssid *start = ssid, *tssid;
 362                 int freqs_set = 0;
 363                 if (ssid == NULL && max_ssids > 1)
 364                         ssid = wpa_s->conf->ssid;
 365                 while (ssid) {
 366                         if (!ssid->disabled && ssid->scan_ssid) {
 367                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 368                                                   ssid->ssid, ssid->ssid_len);
 369                                 params.ssids[params.num_ssids].ssid =
 370                                         ssid->ssid;
 371                                 params.ssids[params.num_ssids].ssid_len =
 372                                         ssid->ssid_len;
 373                                 params.num_ssids++;
 374                                 if (params.num_ssids + 1 >= max_ssids)
 375                                         break;
 376                         }
 377                         ssid = ssid->next;
 378                         if (ssid == start)
 379                                 break;
 380                         if (ssid == NULL && max_ssids > 1 &&
 381                             start != wpa_s->conf->ssid)
 382                                 ssid = wpa_s->conf->ssid;
 383                 }
 384
 385                 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
 386                         if (tssid->disabled)
 387                                 continue;
 388                         if ((params.freqs || !freqs_set) && tssid->scan_freq) {
 389                                 int_array_concat(&params.freqs,
 390                                                  tssid->scan_freq);
 391                         } else {
 392                                 os_free(params.freqs);
 393                                 params.freqs = NULL;
 394                         }
 395                         freqs_set = 1;
 396                 }
 397                 int_array_sort_unique(params.freqs);
 398         }
 399
 400         if (ssid) {
 401                 wpa_s->prev_scan_ssid = ssid;
 402                 if (max_ssids > 1) {
 403                         wpa_dbg(wpa_s, MSG_DEBUG, "Include wildcard SSID in "
 404                                 "the scan request");
 405                         params.num_ssids++;
 406                 }
 407                 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for specific "
 408                         "SSID(s)");
 409         } else {
 410                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 411                 params.num_ssids++;
 412                 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for wildcard "
 413                         "SSID");
 414         }
 415
 416 #ifdef CONFIG_P2P
 417         wpa_s->wps->dev.p2p = 1;
 418         if (!wps) {
 419                 wps = 1;
 420                 req_type = WPS_REQ_ENROLLEE_INFO;
 421         }
 422
 423         if (params.freqs == NULL && wpa_s->p2p_in_provisioning &&
 424             wpa_s->go_params) {
 425                 /* Optimize provisioning state scan based on GO information */
 426                 if (wpa_s->p2p_in_provisioning < 5 &&
 427                     wpa_s->go_params->freq > 0) {
 428                         wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only GO "
 429                                 "preferred frequency %d MHz",
 430                                 wpa_s->go_params->freq);
 431                         params.freqs = os_zalloc(2 * sizeof(int));
 432                         if (params.freqs)
 433                                 params.freqs[0] = wpa_s->go_params->freq;
 434                 } else if (wpa_s->p2p_in_provisioning < 8 &&
 435                            wpa_s->go_params->freq_list[0]) {
 436                         wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only common "
 437                                 "channels");
 438                         int_array_concat(&params.freqs,
 439                                          wpa_s->go_params->freq_list);
 440                         if (params.freqs)
 441                                 int_array_sort_unique(params.freqs);
 442                 }
 443                 wpa_s->p2p_in_provisioning++;
 444         }
 445 #endif /* CONFIG_P2P */
 446
 447 #ifdef CONFIG_WPS
 448         if (params.freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
 449                 /*
 450                  * Optimize post-provisioning scan based on channel used
 451                  * during provisioning.
 452                  */
 453                 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Scan only frequency %u MHz "
 454                         "that was used during provisioning", wpa_s->wps_freq);
 455                 params.freqs = os_zalloc(2 * sizeof(int));
 456                 if (params.freqs)
 457                         params.freqs[0] = wpa_s->wps_freq;
 458                 wpa_s->after_wps--;
 459         }
 460
 461         if (wps) {
 462                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 463                                                 wpa_s->wps->uuid, req_type,
 464                                                 0, NULL);
 465                 if (wps_ie) {
 466                         params.extra_ies = wpabuf_head(wps_ie);
 467                         params.extra_ies_len = wpabuf_len(wps_ie);
 468                 }
 469         }
 470 #endif /* CONFIG_WPS */
 471
 472 #ifdef CONFIG_P2P
 473         if (wps_ie) {
 474                 if (wpabuf_resize(&wps_ie, 100) == 0) {
 475                         wpas_p2p_scan_ie(wpa_s, wps_ie);
 476                         params.extra_ies = wpabuf_head(wps_ie);
 477                         params.extra_ies_len = wpabuf_len(wps_ie);
 478                 }
 479         }
 480 #endif /* CONFIG_P2P */
 481
 482         if (params.freqs == NULL && wpa_s->next_scan_freqs) {
 483                 wpa_dbg(wpa_s, MSG_DEBUG, "Optimize scan based on previously "
 484                         "generated frequency list");
 485                 params.freqs = wpa_s->next_scan_freqs;
 486         } else
 487                 os_free(wpa_s->next_scan_freqs);
 488         wpa_s->next_scan_freqs = NULL;
 489
 490         params.filter_ssids = wpa_supplicant_build_filter_ssids(
 491                 wpa_s->conf, &params.num_filter_ssids);
 492
 493         ret = wpa_supplicant_trigger_scan(wpa_s, &params);
 494
 495         wpabuf_free(wps_ie);
 496         os_free(params.freqs);
 497         os_free(params.filter_ssids);
 498
 499         if (ret) {
 500                 wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate AP scan");
 501                 if (prev_state != wpa_s->wpa_state)
 502                         wpa_supplicant_set_state(wpa_s, prev_state);
 503                 wpa_supplicant_req_scan(wpa_s, 1, 0);
 504         }
 505 }
 506
 507
 508 /**
 509  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 510  * @wpa_s: Pointer to wpa_supplicant data
 511  * @sec: Number of seconds after which to scan
 512  * @usec: Number of microseconds after which to scan
 513  *
 514  * This function is used to schedule a scan for neighboring access points after
 515  * the specified time.
 516  */
 517 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 518 {
 519         /* If there's at least one network that should be specifically scanned
 520          * then don't cancel the scan and reschedule.  Some drivers do
 521          * background scanning which generates frequent scan results, and that
 522          * causes the specific SSID scan to get continually pushed back and
 523          * never happen, which causes hidden APs to never get probe-scanned.
 524          */
 525         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 526             wpa_s->conf->ap_scan == 1) {
 527                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 528
 529                 while (ssid) {
 530                         if (!ssid->disabled && ssid->scan_ssid)
 531                                 break;
 532                         ssid = ssid->next;
 533                 }
 534                 if (ssid) {
 535                         wpa_dbg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 536                                 "ensure that specific SSID scans occur");
 537                         return;
 538                 }
 539         }
 540
 541         wpa_dbg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 542                 sec, usec);
 543         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 544         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 545 }
 546
 547
 548 /**
 549  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 550  * @wpa_s: Pointer to wpa_supplicant data
 551  *
 552  * This function is used to cancel a scan request scheduled with
 553  * wpa_supplicant_req_scan().
 554  */
 555 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 556 {
 557         wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 558         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 559 }
 560
 561
 562 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
 563                                     int scanning)
 564 {
 565         if (wpa_s->scanning != scanning) {
 566                 wpa_s->scanning = scanning;
 567                 wpas_notify_scanning(wpa_s);
 568         }
 569 }
 570
 571
 572 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
 573 {
 574         int rate = 0;
 575         const u8 *ie;
 576         int i;
 577
 578         ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
 579         for (i = 0; ie && i < ie[1]; i++) {
 580                 if ((ie[i + 2] & 0x7f) > rate)
 581                         rate = ie[i + 2] & 0x7f;
 582         }
 583
 584         ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
 585         for (i = 0; ie && i < ie[1]; i++) {
 586                 if ((ie[i + 2] & 0x7f) > rate)
 587                         rate = ie[i + 2] & 0x7f;
 588         }
 589
 590         return rate;
 591 }
 592
 593
 594 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
 595 {
 596         const u8 *end, *pos;
 597
 598         pos = (const u8 *) (res + 1);
 599         end = pos + res->ie_len;
 600
 601         while (pos + 1 < end) {
 602                 if (pos + 2 + pos[1] > end)
 603                         break;
 604                 if (pos[0] == ie)
 605                         return pos;
 606                 pos += 2 + pos[1];
 607         }
 608
 609         return NULL;
 610 }
 611
 612
 613 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
 614                                   u32 vendor_type)
 615 {
 616         const u8 *end, *pos;
 617
 618         pos = (const u8 *) (res + 1);
 619         end = pos + res->ie_len;
 620
 621         while (pos + 1 < end) {
 622                 if (pos + 2 + pos[1] > end)
 623                         break;
 624                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 625                     vendor_type == WPA_GET_BE32(&pos[2]))
 626                         return pos;
 627                 pos += 2 + pos[1];
 628         }
 629
 630         return NULL;
 631 }
 632
 633
 634 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
 635                                              u32 vendor_type)
 636 {
 637         struct wpabuf *buf;
 638         const u8 *end, *pos;
 639
 640         buf = wpabuf_alloc(res->ie_len);
 641         if (buf == NULL)
 642                 return NULL;
 643
 644         pos = (const u8 *) (res + 1);
 645         end = pos + res->ie_len;
 646
 647         while (pos + 1 < end) {
 648                 if (pos + 2 + pos[1] > end)
 649                         break;
 650                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 651                     vendor_type == WPA_GET_BE32(&pos[2]))
 652                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
 653                 pos += 2 + pos[1];
 654         }
 655
 656         if (wpabuf_len(buf) == 0) {
 657                 wpabuf_free(buf);
 658                 buf = NULL;
 659         }
 660
 661         return buf;
 662 }
 663
 664
 665 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
 666         const struct wpa_scan_res *res, u32 vendor_type)
 667 {
 668         struct wpabuf *buf;
 669         const u8 *end, *pos;
 670
 671         if (res->beacon_ie_len == 0)
 672                 return NULL;
 673         buf = wpabuf_alloc(res->beacon_ie_len);
 674         if (buf == NULL)
 675                 return NULL;
 676
 677         pos = (const u8 *) (res + 1);
 678         pos += res->ie_len;
 679         end = pos + res->beacon_ie_len;
 680
 681         while (pos + 1 < end) {
 682                 if (pos + 2 + pos[1] > end)
 683                         break;
 684                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 685                     vendor_type == WPA_GET_BE32(&pos[2]))
 686                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
 687                 pos += 2 + pos[1];
 688         }
 689
 690         if (wpabuf_len(buf) == 0) {
 691                 wpabuf_free(buf);
 692                 buf = NULL;
 693         }
 694
 695         return buf;
 696 }
 697
 698
 699 /* Compare function for sorting scan results. Return >0 if @b is considered
 700  * better. */
 701 static int wpa_scan_result_compar(const void *a, const void *b)
 702 {
 703         struct wpa_scan_res **_wa = (void *) a;
 704         struct wpa_scan_res **_wb = (void *) b;
 705         struct wpa_scan_res *wa = *_wa;
 706         struct wpa_scan_res *wb = *_wb;
 707         int wpa_a, wpa_b, maxrate_a, maxrate_b;
 708
 709         /* WPA/WPA2 support preferred */
 710         wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
 711                 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
 712         wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
 713                 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
 714
 715         if (wpa_b && !wpa_a)
 716                 return 1;
 717         if (!wpa_b && wpa_a)
 718                 return -1;
 719
 720         /* privacy support preferred */
 721         if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
 722             (wb->caps & IEEE80211_CAP_PRIVACY))
 723                 return 1;
 724         if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
 725             (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
 726                 return -1;
 727
 728         /* best/max rate preferred if signal level close enough XXX */
 729         if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
 730             (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
 731                 maxrate_a = wpa_scan_get_max_rate(wa);
 732                 maxrate_b = wpa_scan_get_max_rate(wb);
 733                 if (maxrate_a != maxrate_b)
 734                         return maxrate_b - maxrate_a;
 735         }
 736
 737         /* use freq for channel preference */
 738
 739         /* all things being equal, use signal level; if signal levels are
 740          * identical, use quality values since some drivers may only report
 741          * that value and leave the signal level zero */
 742         if (wb->level == wa->level)
 743                 return wb->qual - wa->qual;
 744         return wb->level - wa->level;
 745 }
 746
 747
 748 #ifdef CONFIG_WPS
 749 /* Compare function for sorting scan results when searching a WPS AP for
 750  * provisioning. Return >0 if @b is considered better. */
 751 static int wpa_scan_result_wps_compar(const void *a, const void *b)
 752 {
 753         struct wpa_scan_res **_wa = (void *) a;
 754         struct wpa_scan_res **_wb = (void *) b;
 755         struct wpa_scan_res *wa = *_wa;
 756         struct wpa_scan_res *wb = *_wb;
 757         int uses_wps_a, uses_wps_b;
 758         struct wpabuf *wps_a, *wps_b;
 759         int res;
 760
 761         /* Optimization - check WPS IE existence before allocated memory and
 762          * doing full reassembly. */
 763         uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
 764         uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
 765         if (uses_wps_a && !uses_wps_b)
 766                 return -1;
 767         if (!uses_wps_a && uses_wps_b)
 768                 return 1;
 769
 770         if (uses_wps_a && uses_wps_b) {
 771                 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
 772                 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
 773                 res = wps_ap_priority_compar(wps_a, wps_b);
 774                 wpabuf_free(wps_a);
 775                 wpabuf_free(wps_b);
 776                 if (res)
 777                         return res;
 778         }
 779
 780         /*
 781          * Do not use current AP security policy as a sorting criteria during
 782          * WPS provisioning step since the AP may get reconfigured at the
 783          * completion of provisioning.
 784          */
 785
 786         /* all things being equal, use signal level; if signal levels are
 787          * identical, use quality values since some drivers may only report
 788          * that value and leave the signal level zero */
 789         if (wb->level == wa->level)
 790                 return wb->qual - wa->qual;
 791         return wb->level - wa->level;
 792 }
 793 #endif /* CONFIG_WPS */
 794
 795
 796 /**
 797  * wpa_supplicant_get_scan_results - Get scan results
 798  * @wpa_s: Pointer to wpa_supplicant data
 799  * @info: Information about what was scanned or %NULL if not available
 800  * @new_scan: Whether a new scan was performed
 801  * Returns: Scan results, %NULL on failure
 802  *
 803  * This function request the current scan results from the driver and updates
 804  * the local BSS list wpa_s->bss. The caller is responsible for freeing the
 805  * results with wpa_scan_results_free().
 806  */
 807 struct wpa_scan_results *
 808 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
 809                                 struct scan_info *info, int new_scan)
 810 {
 811         struct wpa_scan_results *scan_res;
 812         size_t i;
 813         int (*compar)(const void *, const void *) = wpa_scan_result_compar;
 814
 815         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
 816                 scan_res = ieee80211_sta_get_scan_results(wpa_s);
 817         else
 818                 scan_res = wpa_drv_get_scan_results2(wpa_s);
 819         if (scan_res == NULL) {
 820                 wpa_dbg(wpa_s, MSG_DEBUG, "Failed to get scan results");
 821                 return NULL;
 822         }
 823
 824 #ifdef CONFIG_WPS
 825         if (wpas_wps_in_progress(wpa_s)) {
 826                 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Order scan results with WPS "
 827                         "provisioning rules");
 828                 compar = wpa_scan_result_wps_compar;
 829         }
 830 #endif /* CONFIG_WPS */
 831
 832         qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
 833               compar);
 834
 835         wpa_bss_update_start(wpa_s);
 836         for (i = 0; i < scan_res->num; i++)
 837                 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
 838         wpa_bss_update_end(wpa_s, info, new_scan);
 839
 840         return scan_res;
 841 }
 842
 843
 844 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
 845 {
 846         struct wpa_scan_results *scan_res;
 847         scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
 848         if (scan_res == NULL)
 849                 return -1;
 850         wpa_scan_results_free(scan_res);
 851
 852         return 0;
 853 }
 854
 855
 856 void wpa_scan_results_free(struct wpa_scan_results *res)
 857 {
 858         size_t i;
 859
 860         if (res == NULL)
 861                 return;
 862
 863         for (i = 0; i < res->num; i++)
 864                 os_free(res->res[i]);
 865         os_free(res->res);
 866         os_free(res);
 867 }