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