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 "wps_supplicant.h"
  24 #include "p2p_supplicant.h"
  25 #include "p2p/p2p.h"
  26 #include "notify.h"
  27 #include "bss.h"
  28 #include "scan.h"
  29
  30
  31 static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
  32 {
  33         struct wpa_ssid *ssid;
  34         union wpa_event_data data;
  35
  36         ssid = wpa_supplicant_get_ssid(wpa_s);
  37         if (ssid == NULL)
  38                 return;
  39
  40         if (wpa_s->current_ssid == NULL) {
  41                 wpa_s->current_ssid = ssid;
  42                 if (wpa_s->current_ssid != NULL)
  43                         wpas_notify_network_changed(wpa_s);
  44         }
  45         wpa_supplicant_initiate_eapol(wpa_s);
  46         wpa_dbg(wpa_s, MSG_DEBUG, "Already associated with a configured "
  47                 "network - generating associated event");
  48         os_memset(&data, 0, sizeof(data));
  49         wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);
  50 }
  51
  52
  53 #ifdef CONFIG_WPS
  54 static int wpas_wps_in_use(struct wpa_supplicant *wpa_s,
  55                            enum wps_request_type *req_type)
  56 {
  57         struct wpa_ssid *ssid;
  58         int wps = 0;
  59
  60         for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
  61                 if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
  62                         continue;
  63
  64                 wps = 1;
  65                 *req_type = wpas_wps_get_req_type(ssid);
  66                 if (!ssid->eap.phase1)
  67                         continue;
  68
  69                 if (os_strstr(ssid->eap.phase1, "pbc=1"))
  70                         return 2;
  71         }
  72
  73 #ifdef CONFIG_P2P
  74         wpa_s->wps->dev.p2p = 1;
  75         if (!wps) {
  76                 wps = 1;
  77                 *req_type = WPS_REQ_ENROLLEE_INFO;
  78         }
  79 #endif /* CONFIG_P2P */
  80
  81         return wps;
  82 }
  83 #endif /* CONFIG_WPS */
  84
  85
  86 int wpa_supplicant_enabled_networks(struct wpa_config *conf)
  87 {
  88         struct wpa_ssid *ssid = conf->ssid;
  89         int count = 0;
  90         while (ssid) {
  91                 if (!ssid->disabled)
  92                         count++;
  93                 ssid = ssid->next;
  94         }
  95         return count;
  96 }
  97
  98
  99 static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
 100                                      struct wpa_ssid *ssid)
 101 {
 102         while (ssid) {
 103                 if (!ssid->disabled)
 104                         break;
 105                 ssid = ssid->next;
 106         }
 107
 108         /* ap_scan=2 mode - try to associate with each SSID. */
 109         if (ssid == NULL) {
 110                 wpa_dbg(wpa_s, MSG_DEBUG, "wpa_supplicant_assoc_try: Reached "
 111                         "end of scan list - go back to beginning");
 112                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 113                 wpa_supplicant_req_scan(wpa_s, 0, 0);
 114                 return;
 115         }
 116         if (ssid->next) {
 117                 /* Continue from the next SSID on the next attempt. */
 118                 wpa_s->prev_scan_ssid = ssid;
 119         } else {
 120                 /* Start from the beginning of the SSID list. */
 121                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 122         }
 123         wpa_supplicant_associate(wpa_s, NULL, ssid);
 124 }
 125
 126
 127 static int int_array_len(const int *a)
 128 {
 129         int i;
 130         for (i = 0; a && a[i]; i++)
 131                 ;
 132         return i;
 133 }
 134
 135
 136 static void int_array_concat(int **res, const int *a)
 137 {
 138         int reslen, alen, i;
 139         int *n;
 140
 141         reslen = int_array_len(*res);
 142         alen = int_array_len(a);
 143
 144         n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
 145         if (n == NULL) {
 146                 os_free(*res);
 147                 *res = NULL;
 148                 return;
 149         }
 150         for (i = 0; i <= alen; i++)
 151                 n[reslen + i] = a[i];
 152         *res = n;
 153 }
 154
 155
 156 static int freq_cmp(const void *a, const void *b)
 157 {
 158         int _a = *(int *) a;
 159         int _b = *(int *) b;
 160
 161         if (_a == 0)
 162                 return 1;
 163         if (_b == 0)
 164                 return -1;
 165         return _a - _b;
 166 }
 167
 168
 169 static void int_array_sort_unique(int *a)
 170 {
 171         int alen;
 172         int i, j;
 173
 174         if (a == NULL)
 175                 return;
 176
 177         alen = int_array_len(a);
 178         qsort(a, alen, sizeof(int), freq_cmp);
 179
 180         i = 0;
 181         j = 1;
 182         while (a[i] && a[j]) {
 183                 if (a[i] == a[j]) {
 184                         j++;
 185                         continue;
 186                 }
 187                 a[++i] = a[j++];
 188         }
 189         if (a[i])
 190                 i++;
 191         a[i] = 0;
 192 }
 193
 194
 195 int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
 196                                 struct wpa_driver_scan_params *params)
 197 {
 198         int ret;
 199
 200         wpa_supplicant_notify_scanning(wpa_s, 1);
 201
 202         ret = wpa_drv_scan(wpa_s, params);
 203         if (ret) {
 204                 wpa_supplicant_notify_scanning(wpa_s, 0);
 205                 wpas_notify_scan_done(wpa_s, 0);
 206         } else
 207                 wpa_s->scan_runs++;
 208
 209         return ret;
 210 }
 211
 212
 213 static void
 214 wpa_supplicant_delayed_sched_scan_timeout(void *eloop_ctx, void *timeout_ctx)
 215 {
 216         struct wpa_supplicant *wpa_s = eloop_ctx;
 217
 218         wpa_dbg(wpa_s, MSG_DEBUG, "Starting delayed sched scan");
 219
 220         if (wpa_supplicant_req_sched_scan(wpa_s))
 221                 wpa_supplicant_req_scan(wpa_s, 0, 0);
 222 }
 223
 224
 225 static void
 226 wpa_supplicant_sched_scan_timeout(void *eloop_ctx, void *timeout_ctx)
 227 {
 228         struct wpa_supplicant *wpa_s = eloop_ctx;
 229
 230         wpa_dbg(wpa_s, MSG_DEBUG, "Sched scan timeout - stopping it");
 231
 232         wpa_s->sched_scan_timed_out = 1;
 233         wpa_supplicant_cancel_sched_scan(wpa_s);
 234 }
 235
 236
 237 static int
 238 wpa_supplicant_start_sched_scan(struct wpa_supplicant *wpa_s,
 239                                 struct wpa_driver_scan_params *params,
 240                                 int interval)
 241 {
 242         int ret;
 243
 244         wpa_supplicant_notify_scanning(wpa_s, 1);
 245         ret = wpa_drv_sched_scan(wpa_s, params, interval * 1000);
 246         if (ret)
 247                 wpa_supplicant_notify_scanning(wpa_s, 0);
 248         else
 249                 wpa_s->sched_scanning = 1;
 250
 251         return ret;
 252 }
 253
 254
 255 static int wpa_supplicant_stop_sched_scan(struct wpa_supplicant *wpa_s)
 256 {
 257         int ret;
 258
 259         ret = wpa_drv_stop_sched_scan(wpa_s);
 260         if (ret) {
 261                 wpa_dbg(wpa_s, MSG_DEBUG, "stopping sched_scan failed!");
 262                 /* TODO: what to do if stopping fails? */
 263                 return -1;
 264         }
 265
 266         return ret;
 267 }
 268
 269
 270 static struct wpa_driver_scan_filter *
 271 wpa_supplicant_build_filter_ssids(struct wpa_config *conf, size_t *num_ssids)
 272 {
 273         struct wpa_driver_scan_filter *ssids;
 274         struct wpa_ssid *ssid;
 275         size_t count;
 276
 277         *num_ssids = 0;
 278         if (!conf->filter_ssids)
 279                 return NULL;
 280
 281         for (count = 0, ssid = conf->ssid; ssid; ssid = ssid->next) {
 282                 if (ssid->ssid && ssid->ssid_len)
 283                         count++;
 284         }
 285         if (count == 0)
 286                 return NULL;
 287         ssids = os_zalloc(count * sizeof(struct wpa_driver_scan_filter));
 288         if (ssids == NULL)
 289                 return NULL;
 290
 291         for (ssid = conf->ssid; ssid; ssid = ssid->next) {
 292                 if (!ssid->ssid || !ssid->ssid_len)
 293                         continue;
 294                 os_memcpy(ssids[*num_ssids].ssid, ssid->ssid, ssid->ssid_len);
 295                 ssids[*num_ssids].ssid_len = ssid->ssid_len;
 296                 (*num_ssids)++;
 297         }
 298
 299         return ssids;
 300 }
 301
 302
 303 static void wpa_supplicant_optimize_freqs(
 304         struct wpa_supplicant *wpa_s, struct wpa_driver_scan_params *params)
 305 {
 306 #ifdef CONFIG_P2P
 307         if (params->freqs == NULL && wpa_s->p2p_in_provisioning &&
 308             wpa_s->go_params) {
 309                 /* Optimize provisioning state scan based on GO information */
 310                 if (wpa_s->p2p_in_provisioning < 5 &&
 311                     wpa_s->go_params->freq > 0) {
 312                         wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only GO "
 313                                 "preferred frequency %d MHz",
 314                                 wpa_s->go_params->freq);
 315                         params->freqs = os_zalloc(2 * sizeof(int));
 316                         if (params->freqs)
 317                                 params->freqs[0] = wpa_s->go_params->freq;
 318                 } else if (wpa_s->p2p_in_provisioning < 8 &&
 319                            wpa_s->go_params->freq_list[0]) {
 320                         wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only common "
 321                                 "channels");
 322                         int_array_concat(&params->freqs,
 323                                          wpa_s->go_params->freq_list);
 324                         if (params->freqs)
 325                                 int_array_sort_unique(params->freqs);
 326                 }
 327                 wpa_s->p2p_in_provisioning++;
 328         }
 329 #endif /* CONFIG_P2P */
 330
 331 #ifdef CONFIG_WPS
 332         if (params->freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
 333                 /*
 334                  * Optimize post-provisioning scan based on channel used
 335                  * during provisioning.
 336                  */
 337                 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Scan only frequency %u MHz "
 338                         "that was used during provisioning", wpa_s->wps_freq);
 339                 params->freqs = os_zalloc(2 * sizeof(int));
 340                 if (params->freqs)
 341                         params->freqs[0] = wpa_s->wps_freq;
 342                 wpa_s->after_wps--;
 343         }
 344
 345 #endif /* CONFIG_WPS */
 346 }
 347
 348
 349 #ifdef CONFIG_INTERWORKING
 350 static void wpas_add_interworking_elements(struct wpa_supplicant *wpa_s,
 351                                            struct wpabuf *buf)
 352 {
 353         if (wpa_s->conf->interworking == 0)
 354                 return;
 355
 356         wpabuf_put_u8(buf, WLAN_EID_EXT_CAPAB);
 357         wpabuf_put_u8(buf, 4);
 358         wpabuf_put_u8(buf, 0x00);
 359         wpabuf_put_u8(buf, 0x00);
 360         wpabuf_put_u8(buf, 0x00);
 361         wpabuf_put_u8(buf, 0x80); /* Bit 31 - Interworking */
 362
 363         wpabuf_put_u8(buf, WLAN_EID_INTERWORKING);
 364         wpabuf_put_u8(buf, is_zero_ether_addr(wpa_s->conf->hessid) ? 1 :
 365                       1 + ETH_ALEN);
 366         wpabuf_put_u8(buf, wpa_s->conf->access_network_type);
 367         /* No Venue Info */
 368         if (!is_zero_ether_addr(wpa_s->conf->hessid))
 369                 wpabuf_put_data(buf, wpa_s->conf->hessid, ETH_ALEN);
 370 }
 371 #endif /* CONFIG_INTERWORKING */
 372
 373
 374 static struct wpabuf *
 375 wpa_supplicant_extra_ies(struct wpa_supplicant *wpa_s,
 376                          struct wpa_driver_scan_params *params)
 377 {
 378         struct wpabuf *extra_ie = NULL;
 379 #ifdef CONFIG_WPS
 380         int wps = 0;
 381         enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
 382 #endif /* CONFIG_WPS */
 383
 384 #ifdef CONFIG_INTERWORKING
 385         if (wpa_s->conf->interworking &&
 386             wpabuf_resize(&extra_ie, 100) == 0)
 387                 wpas_add_interworking_elements(wpa_s, extra_ie);
 388 #endif /* CONFIG_INTERWORKING */
 389
 390 #ifdef CONFIG_WPS
 391         wps = wpas_wps_in_use(wpa_s, &req_type);
 392
 393         if (wps) {
 394                 struct wpabuf *wps_ie;
 395                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 396                                                 wpa_s->wps->uuid, req_type,
 397                                                 0, NULL);
 398                 if (wps_ie) {
 399                         if (wpabuf_resize(&extra_ie, wpabuf_len(wps_ie)) == 0)
 400                                 wpabuf_put_buf(extra_ie, wps_ie);
 401                         wpabuf_free(wps_ie);
 402                 }
 403         }
 404
 405 #ifdef CONFIG_P2P
 406         if (wps) {
 407                 size_t ielen = p2p_scan_ie_buf_len(wpa_s->global->p2p);
 408                 if (wpabuf_resize(&extra_ie, ielen) == 0)
 409                         wpas_p2p_scan_ie(wpa_s, extra_ie);
 410         }
 411 #endif /* CONFIG_P2P */
 412
 413 #endif /* CONFIG_WPS */
 414
 415         return extra_ie;
 416 }
 417
 418
 419 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
 420 {
 421         struct wpa_supplicant *wpa_s = eloop_ctx;
 422         struct wpa_ssid *ssid;
 423         int scan_req = 0, ret;
 424         struct wpabuf *extra_ie;
 425         struct wpa_driver_scan_params params;
 426         size_t max_ssids;
 427         enum wpa_states prev_state;
 428
 429         if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
 430                 wpa_dbg(wpa_s, MSG_DEBUG, "Skip scan - interface disabled");
 431                 return;
 432         }
 433
 434         if (wpa_s->disconnected && !wpa_s->scan_req) {
 435                 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
 436                 return;
 437         }
 438
 439         if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
 440             !wpa_s->scan_req) {
 441                 wpa_dbg(wpa_s, MSG_DEBUG, "No enabled networks - do not scan");
 442                 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
 443                 return;
 444         }
 445
 446         if (wpa_s->conf->ap_scan != 0 &&
 447             (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
 448                 wpa_dbg(wpa_s, MSG_DEBUG, "Using wired authentication - "
 449                         "overriding ap_scan configuration");
 450                 wpa_s->conf->ap_scan = 0;
 451                 wpas_notify_ap_scan_changed(wpa_s);
 452         }
 453
 454         if (wpa_s->conf->ap_scan == 0) {
 455                 wpa_supplicant_gen_assoc_event(wpa_s);
 456                 return;
 457         }
 458
 459 #ifdef CONFIG_P2P
 460         if (wpas_p2p_in_progress(wpa_s)) {
 461                 if (wpa_s->wpa_state == WPA_SCANNING) {
 462                         wpa_dbg(wpa_s, MSG_DEBUG, "Delay station mode scan "
 463                                 "while P2P operation is in progress");
 464                         wpa_supplicant_req_scan(wpa_s, 5, 0);
 465                 } else {
 466                         wpa_dbg(wpa_s, MSG_DEBUG, "Do not request scan while "
 467                                 "P2P operation is in progress");
 468                 }
 469                 return;
 470         }
 471 #endif /* CONFIG_P2P */
 472
 473         if (wpa_s->conf->ap_scan == 2)
 474                 max_ssids = 1;
 475         else {
 476                 max_ssids = wpa_s->max_scan_ssids;
 477                 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
 478                         max_ssids = WPAS_MAX_SCAN_SSIDS;
 479         }
 480
 481         scan_req = wpa_s->scan_req;
 482         wpa_s->scan_req = 0;
 483
 484         os_memset(&params, 0, sizeof(params));
 485
 486         prev_state = wpa_s->wpa_state;
 487         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 488             wpa_s->wpa_state == WPA_INACTIVE)
 489                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 490
 491         if (scan_req != 2 && wpa_s->connect_without_scan) {
 492                 for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
 493                         if (ssid == wpa_s->connect_without_scan)
 494                                 break;
 495                 }
 496                 wpa_s->connect_without_scan = NULL;
 497                 if (ssid) {
 498                         wpa_printf(MSG_DEBUG, "Start a pre-selected network "
 499                                    "without scan step");
 500                         wpa_supplicant_associate(wpa_s, NULL, ssid);
 501                         return;
 502                 }
 503         }
 504
 505         /* Find the starting point from which to continue scanning */
 506         ssid = wpa_s->conf->ssid;
 507         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
 508                 while (ssid) {
 509                         if (ssid == wpa_s->prev_scan_ssid) {
 510                                 ssid = ssid->next;
 511                                 break;
 512                         }
 513                         ssid = ssid->next;
 514                 }
 515         }
 516
 517         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
 518                 wpa_s->connect_without_scan = NULL;
 519                 wpa_supplicant_assoc_try(wpa_s, ssid);
 520                 return;
 521         } else if (wpa_s->conf->ap_scan == 2) {
 522                 /*
 523                  * User-initiated scan request in ap_scan == 2; scan with
 524                  * wildcard SSID.
 525                  */
 526                 ssid = NULL;
 527         } else {
 528                 struct wpa_ssid *start = ssid, *tssid;
 529                 int freqs_set = 0;
 530                 if (ssid == NULL && max_ssids > 1)
 531                         ssid = wpa_s->conf->ssid;
 532                 while (ssid) {
 533                         if (!ssid->disabled && ssid->scan_ssid) {
 534                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 535                                                   ssid->ssid, ssid->ssid_len);
 536                                 params.ssids[params.num_ssids].ssid =
 537                                         ssid->ssid;
 538                                 params.ssids[params.num_ssids].ssid_len =
 539                                         ssid->ssid_len;
 540                                 params.num_ssids++;
 541                                 if (params.num_ssids + 1 >= max_ssids)
 542                                         break;
 543                         }
 544                         ssid = ssid->next;
 545                         if (ssid == start)
 546                                 break;
 547                         if (ssid == NULL && max_ssids > 1 &&
 548                             start != wpa_s->conf->ssid)
 549                                 ssid = wpa_s->conf->ssid;
 550                 }
 551
 552                 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
 553                         if (tssid->disabled)
 554                                 continue;
 555                         if ((params.freqs || !freqs_set) && tssid->scan_freq) {
 556                                 int_array_concat(&params.freqs,
 557                                                  tssid->scan_freq);
 558                         } else {
 559                                 os_free(params.freqs);
 560                                 params.freqs = NULL;
 561                         }
 562                         freqs_set = 1;
 563                 }
 564                 int_array_sort_unique(params.freqs);
 565         }
 566
 567         if (ssid) {
 568                 wpa_s->prev_scan_ssid = ssid;
 569                 if (max_ssids > 1) {
 570                         wpa_dbg(wpa_s, MSG_DEBUG, "Include wildcard SSID in "
 571                                 "the scan request");
 572                         params.num_ssids++;
 573                 }
 574                 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for specific "
 575                         "SSID(s)");
 576         } else {
 577                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 578                 params.num_ssids++;
 579                 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for wildcard "
 580                         "SSID");
 581         }
 582
 583         wpa_supplicant_optimize_freqs(wpa_s, &params);
 584         extra_ie = wpa_supplicant_extra_ies(wpa_s, &params);
 585
 586         if (params.freqs == NULL && wpa_s->next_scan_freqs) {
 587                 wpa_dbg(wpa_s, MSG_DEBUG, "Optimize scan based on previously "
 588                         "generated frequency list");
 589                 params.freqs = wpa_s->next_scan_freqs;
 590         } else
 591                 os_free(wpa_s->next_scan_freqs);
 592         wpa_s->next_scan_freqs = NULL;
 593
 594         params.filter_ssids = wpa_supplicant_build_filter_ssids(
 595                 wpa_s->conf, &params.num_filter_ssids);
 596         if (extra_ie) {
 597                 params.extra_ies = wpabuf_head(extra_ie);
 598                 params.extra_ies_len = wpabuf_len(extra_ie);
 599         }
 600
 601 #ifdef CONFIG_P2P
 602         if (wpa_s->p2p_in_provisioning) {
 603                 /*
 604                  * The interface may not yet be in P2P mode, so we have to
 605                  * explicitly request P2P probe to disable CCK rates.
 606                  */
 607                 params.p2p_probe = 1;
 608         }
 609 #endif /* CONFIG_P2P */
 610
 611         ret = wpa_supplicant_trigger_scan(wpa_s, &params);
 612
 613         wpabuf_free(extra_ie);
 614         os_free(params.freqs);
 615         os_free(params.filter_ssids);
 616
 617         if (ret) {
 618                 wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate AP scan");
 619                 if (prev_state != wpa_s->wpa_state)
 620                         wpa_supplicant_set_state(wpa_s, prev_state);
 621                 wpa_supplicant_req_scan(wpa_s, 1, 0);
 622         }
 623 }
 624
 625
 626 /**
 627  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 628  * @wpa_s: Pointer to wpa_supplicant data
 629  * @sec: Number of seconds after which to scan
 630  * @usec: Number of microseconds after which to scan
 631  *
 632  * This function is used to schedule a scan for neighboring access points after
 633  * the specified time.
 634  */
 635 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 636 {
 637         /* If there's at least one network that should be specifically scanned
 638          * then don't cancel the scan and reschedule.  Some drivers do
 639          * background scanning which generates frequent scan results, and that
 640          * causes the specific SSID scan to get continually pushed back and
 641          * never happen, which causes hidden APs to never get probe-scanned.
 642          */
 643         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 644             wpa_s->conf->ap_scan == 1) {
 645                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 646
 647                 while (ssid) {
 648                         if (!ssid->disabled && ssid->scan_ssid)
 649                                 break;
 650                         ssid = ssid->next;
 651                 }
 652                 if (ssid) {
 653                         wpa_dbg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 654                                 "ensure that specific SSID scans occur");
 655                         return;
 656                 }
 657         }
 658
 659         wpa_dbg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 660                 sec, usec);
 661         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 662         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 663 }
 664
 665
 666 /**
 667  * wpa_supplicant_delayed_sched_scan - Request a delayed scheduled scan
 668  * @wpa_s: Pointer to wpa_supplicant data
 669  * @sec: Number of seconds after which to scan
 670  * @usec: Number of microseconds after which to scan
 671  *
 672  * This function is used to schedule periodic scans for neighboring
 673  * access points after the specified time.
 674  */
 675 int wpa_supplicant_delayed_sched_scan(struct wpa_supplicant *wpa_s,
 676                                       int sec, int usec)
 677 {
 678         if (!wpa_s->sched_scan_supported)
 679                 return -1;
 680
 681         eloop_register_timeout(sec, usec,
 682                                wpa_supplicant_delayed_sched_scan_timeout,
 683                                wpa_s, NULL);
 684
 685         return 0;
 686 }
 687
 688
 689 /**
 690  * wpa_supplicant_req_sched_scan - Start a periodic scheduled scan
 691  * @wpa_s: Pointer to wpa_supplicant data
 692  *
 693  * This function is used to schedule periodic scans for neighboring
 694  * access points repeating the scan continuously.
 695  */
 696 int wpa_supplicant_req_sched_scan(struct wpa_supplicant *wpa_s)
 697 {
 698         struct wpa_driver_scan_params params;
 699         enum wpa_states prev_state;
 700         struct wpa_ssid *ssid;
 701         struct wpabuf *wps_ie = NULL;
 702         int ret;
 703         unsigned int max_sched_scan_ssids;
 704
 705         if (!wpa_s->sched_scan_supported)
 706                 return -1;
 707
 708         if (wpa_s->max_sched_scan_ssids > WPAS_MAX_SCAN_SSIDS)
 709                 max_sched_scan_ssids = WPAS_MAX_SCAN_SSIDS;
 710         else
 711                 max_sched_scan_ssids = wpa_s->max_sched_scan_ssids;
 712
 713         if (wpa_s->sched_scanning) {
 714                 wpa_dbg(wpa_s, MSG_DEBUG, "Already sched scanning");
 715                 return 0;
 716         }
 717
 718         os_memset(&params, 0, sizeof(params));
 719
 720         /* If we can't allocate space for the filters, we just don't filter */
 721         params.filter_ssids = os_zalloc(wpa_s->max_match_sets *
 722                                         sizeof(struct wpa_driver_scan_filter));
 723
 724         prev_state = wpa_s->wpa_state;
 725         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 726             wpa_s->wpa_state == WPA_INACTIVE)
 727                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 728
 729         /* Find the starting point from which to continue scanning */
 730         ssid = wpa_s->conf->ssid;
 731         if (wpa_s->prev_sched_ssid) {
 732                 while (ssid) {
 733                         if (ssid == wpa_s->prev_sched_ssid) {
 734                                 ssid = ssid->next;
 735                                 break;
 736                         }
 737                         ssid = ssid->next;
 738                 }
 739         }
 740
 741         if (!ssid || !wpa_s->prev_sched_ssid) {
 742                 wpa_dbg(wpa_s, MSG_DEBUG, "Beginning of SSID list");
 743
 744                 wpa_s->sched_scan_interval = 2;
 745                 wpa_s->sched_scan_timeout = max_sched_scan_ssids * 2;
 746                 wpa_s->first_sched_scan = 1;
 747                 ssid = wpa_s->conf->ssid;
 748                 wpa_s->prev_sched_ssid = ssid;
 749         }
 750
 751         while (ssid) {
 752                 if (ssid->disabled) {
 753                         wpa_s->prev_sched_ssid = ssid;
 754                         ssid = ssid->next;
 755                         continue;
 756                 }
 757
 758                 if (params.num_filter_ssids < wpa_s->max_match_sets &&
 759                     params.filter_ssids && ssid->ssid && ssid->ssid_len) {
 760                         wpa_dbg(wpa_s, MSG_DEBUG, "add to filter ssid: %s",
 761                                 wpa_ssid_txt(ssid->ssid, ssid->ssid_len));
 762                         os_memcpy(params.filter_ssids[params.num_filter_ssids].ssid,
 763                                   ssid->ssid, ssid->ssid_len);
 764                         params.filter_ssids[params.num_filter_ssids].ssid_len =
 765                                 ssid->ssid_len;
 766                         params.num_filter_ssids++;
 767                 }
 768
 769                 if (ssid->scan_ssid && ssid->ssid && ssid->ssid_len) {
 770                         wpa_dbg(wpa_s, MSG_DEBUG,
 771                                 "add to active scan ssid: %s",
 772                                 wpa_ssid_txt(ssid->ssid, ssid->ssid_len));
 773                         params.ssids[params.num_ssids].ssid =
 774                                 ssid->ssid;
 775                         params.ssids[params.num_ssids].ssid_len =
 776                                 ssid->ssid_len;
 777                         params.num_ssids++;
 778                         if (params.num_ssids >= max_sched_scan_ssids) {
 779                                 wpa_s->prev_sched_ssid = ssid;
 780                                 break;
 781                         }
 782                 }
 783
 784                 if (params.num_filter_ssids >= wpa_s->max_match_sets)
 785                         break;
 786                 wpa_s->prev_sched_ssid = ssid;
 787                 ssid = ssid->next;
 788         }
 789
 790         if (params.num_filter_ssids == 0) {
 791                 os_free(params.filter_ssids);
 792                 params.filter_ssids = NULL;
 793         }
 794
 795         if (wpa_s->wps)
 796                 wps_ie = wpa_supplicant_extra_ies(wpa_s, &params);
 797
 798         if (ssid || !wpa_s->first_sched_scan) {
 799                 wpa_dbg(wpa_s, MSG_DEBUG,
 800                         "Starting sched scan: interval %d (no timeout)",
 801                         wpa_s->sched_scan_interval);
 802         } else {
 803                 wpa_dbg(wpa_s, MSG_DEBUG,
 804                         "Starting sched scan: interval %d timeout %d",
 805                         wpa_s->sched_scan_interval, wpa_s->sched_scan_timeout);
 806         }
 807
 808         ret = wpa_supplicant_start_sched_scan(wpa_s, &params,
 809                                               wpa_s->sched_scan_interval);
 810         wpabuf_free(wps_ie);
 811         os_free(params.filter_ssids);
 812         if (ret) {
 813                 wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate sched scan");
 814                 if (prev_state != wpa_s->wpa_state)
 815                         wpa_supplicant_set_state(wpa_s, prev_state);
 816                 return ret;
 817         }
 818
 819         /* If we have more SSIDs to scan, add a timeout so we scan them too */
 820         if (ssid || !wpa_s->first_sched_scan) {
 821                 wpa_s->sched_scan_timed_out = 0;
 822                 eloop_register_timeout(wpa_s->sched_scan_timeout, 0,
 823                                        wpa_supplicant_sched_scan_timeout,
 824                                        wpa_s, NULL);
 825                 wpa_s->first_sched_scan = 0;
 826                 wpa_s->sched_scan_timeout /= 2;
 827                 wpa_s->sched_scan_interval *= 2;
 828         }
 829
 830         return 0;
 831 }
 832
 833
 834 /**
 835  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 836  * @wpa_s: Pointer to wpa_supplicant data
 837  *
 838  * This function is used to cancel a scan request scheduled with
 839  * wpa_supplicant_req_scan().
 840  */
 841 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 842 {
 843         wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 844         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 845 }
 846
 847
 848 /**
 849  * wpa_supplicant_cancel_sched_scan - Stop running scheduled scans
 850  * @wpa_s: Pointer to wpa_supplicant data
 851  *
 852  * This function is used to stop a periodic scheduled scan.
 853  */
 854 void wpa_supplicant_cancel_sched_scan(struct wpa_supplicant *wpa_s)
 855 {
 856         if (!wpa_s->sched_scanning)
 857                 return;
 858
 859         wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling sched scan");
 860         eloop_cancel_timeout(wpa_supplicant_sched_scan_timeout, wpa_s, NULL);
 861         wpa_supplicant_stop_sched_scan(wpa_s);
 862 }
 863
 864
 865 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
 866                                     int scanning)
 867 {
 868         if (wpa_s->scanning != scanning) {
 869                 wpa_s->scanning = scanning;
 870                 wpas_notify_scanning(wpa_s);
 871         }
 872 }
 873
 874
 875 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
 876 {
 877         int rate = 0;
 878         const u8 *ie;
 879         int i;
 880
 881         ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
 882         for (i = 0; ie && i < ie[1]; i++) {
 883                 if ((ie[i + 2] & 0x7f) > rate)
 884                         rate = ie[i + 2] & 0x7f;
 885         }
 886
 887         ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
 888         for (i = 0; ie && i < ie[1]; i++) {
 889                 if ((ie[i + 2] & 0x7f) > rate)
 890                         rate = ie[i + 2] & 0x7f;
 891         }
 892
 893         return rate;
 894 }
 895
 896
 897 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
 898 {
 899         const u8 *end, *pos;
 900
 901         pos = (const u8 *) (res + 1);
 902         end = pos + res->ie_len;
 903
 904         while (pos + 1 < end) {
 905                 if (pos + 2 + pos[1] > end)
 906                         break;
 907                 if (pos[0] == ie)
 908                         return pos;
 909                 pos += 2 + pos[1];
 910         }
 911
 912         return NULL;
 913 }
 914
 915
 916 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
 917                                   u32 vendor_type)
 918 {
 919         const u8 *end, *pos;
 920
 921         pos = (const u8 *) (res + 1);
 922         end = pos + res->ie_len;
 923
 924         while (pos + 1 < end) {
 925                 if (pos + 2 + pos[1] > end)
 926                         break;
 927                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 928                     vendor_type == WPA_GET_BE32(&pos[2]))
 929                         return pos;
 930                 pos += 2 + pos[1];
 931         }
 932
 933         return NULL;
 934 }
 935
 936
 937 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
 938                                              u32 vendor_type)
 939 {
 940         struct wpabuf *buf;
 941         const u8 *end, *pos;
 942
 943         buf = wpabuf_alloc(res->ie_len);
 944         if (buf == NULL)
 945                 return NULL;
 946
 947         pos = (const u8 *) (res + 1);
 948         end = pos + res->ie_len;
 949
 950         while (pos + 1 < end) {
 951                 if (pos + 2 + pos[1] > end)
 952                         break;
 953                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 954                     vendor_type == WPA_GET_BE32(&pos[2]))
 955                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
 956                 pos += 2 + pos[1];
 957         }
 958
 959         if (wpabuf_len(buf) == 0) {
 960                 wpabuf_free(buf);
 961                 buf = NULL;
 962         }
 963
 964         return buf;
 965 }
 966
 967
 968 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
 969         const struct wpa_scan_res *res, u32 vendor_type)
 970 {
 971         struct wpabuf *buf;
 972         const u8 *end, *pos;
 973
 974         if (res->beacon_ie_len == 0)
 975                 return NULL;
 976         buf = wpabuf_alloc(res->beacon_ie_len);
 977         if (buf == NULL)
 978                 return NULL;
 979
 980         pos = (const u8 *) (res + 1);
 981         pos += res->ie_len;
 982         end = pos + res->beacon_ie_len;
 983
 984         while (pos + 1 < end) {
 985                 if (pos + 2 + pos[1] > end)
 986                         break;
 987                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
 988                     vendor_type == WPA_GET_BE32(&pos[2]))
 989                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
 990                 pos += 2 + pos[1];
 991         }
 992
 993         if (wpabuf_len(buf) == 0) {
 994                 wpabuf_free(buf);
 995                 buf = NULL;
 996         }
 997
 998         return buf;
 999 }
1000
1001
1002 /*
1003  * Channels with a great SNR can operate at full rate. What is a great SNR?
1004  * This doc https://supportforums.cisco.com/docs/DOC-12954 says, "the general
1005  * rule of thumb is that any SNR above 20 is good." This one
1006  * http://www.cisco.com/en/US/tech/tk722/tk809/technologies_q_and_a_item09186a00805e9a96.shtml#qa23
1007  * recommends 25 as a minimum SNR for 54 Mbps data rate. 30 is chosen here as a
1008  * conservative value.
1009  */
1010 #define GREAT_SNR 30
1011
1012 /* Compare function for sorting scan results. Return >0 if @b is considered
1013  * better. */
1014 static int wpa_scan_result_compar(const void *a, const void *b)
1015 {
1016 #define IS_5GHZ(n) (n > 4000)
1017 #define MIN(a,b) a < b ? a : b
1018         struct wpa_scan_res **_wa = (void *) a;
1019         struct wpa_scan_res **_wb = (void *) b;
1020         struct wpa_scan_res *wa = *_wa;
1021         struct wpa_scan_res *wb = *_wb;
1022         int wpa_a, wpa_b, maxrate_a, maxrate_b;
1023         int snr_a, snr_b;
1024
1025         /* WPA/WPA2 support preferred */
1026         wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
1027                 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
1028         wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
1029                 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
1030
1031         if (wpa_b && !wpa_a)
1032                 return 1;
1033         if (!wpa_b && wpa_a)
1034                 return -1;
1035
1036         /* privacy support preferred */
1037         if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
1038             (wb->caps & IEEE80211_CAP_PRIVACY))
1039                 return 1;
1040         if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
1041             (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
1042                 return -1;
1043
1044         if ((wa->flags & wb->flags & WPA_SCAN_LEVEL_DBM) &&
1045             !((wa->flags | wb->flags) & WPA_SCAN_NOISE_INVALID)) {
1046                 snr_a = MIN(wa->level - wa->noise, GREAT_SNR);
1047                 snr_b = MIN(wb->level - wb->noise, GREAT_SNR);
1048         } else {
1049                 /* Not suitable information to calculate SNR, so use level */
1050                 snr_a = wa->level;
1051                 snr_b = wb->level;
1052         }
1053
1054         /* best/max rate preferred if SNR close enough */
1055         if ((snr_a && snr_b && abs(snr_b - snr_a) < 5) ||
1056             (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
1057                 maxrate_a = wpa_scan_get_max_rate(wa);
1058                 maxrate_b = wpa_scan_get_max_rate(wb);
1059                 if (maxrate_a != maxrate_b)
1060                         return maxrate_b - maxrate_a;
1061                 if (IS_5GHZ(wa->freq) ^ IS_5GHZ(wb->freq))
1062                         return IS_5GHZ(wa->freq) ? -1 : 1;
1063         }
1064
1065         /* use freq for channel preference */
1066
1067         /* all things being equal, use SNR; if SNRs are
1068          * identical, use quality values since some drivers may only report
1069          * that value and leave the signal level zero */
1070         if (snr_b == snr_a)
1071                 return wb->qual - wa->qual;
1072         return snr_b - snr_a;
1073 #undef MIN
1074 #undef IS_5GHZ
1075 }
1076
1077
1078 #ifdef CONFIG_WPS
1079 /* Compare function for sorting scan results when searching a WPS AP for
1080  * provisioning. Return >0 if @b is considered better. */
1081 static int wpa_scan_result_wps_compar(const void *a, const void *b)
1082 {
1083         struct wpa_scan_res **_wa = (void *) a;
1084         struct wpa_scan_res **_wb = (void *) b;
1085         struct wpa_scan_res *wa = *_wa;
1086         struct wpa_scan_res *wb = *_wb;
1087         int uses_wps_a, uses_wps_b;
1088         struct wpabuf *wps_a, *wps_b;
1089         int res;
1090
1091         /* Optimization - check WPS IE existence before allocated memory and
1092          * doing full reassembly. */
1093         uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
1094         uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
1095         if (uses_wps_a && !uses_wps_b)
1096                 return -1;
1097         if (!uses_wps_a && uses_wps_b)
1098                 return 1;
1099
1100         if (uses_wps_a && uses_wps_b) {
1101                 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
1102                 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
1103                 res = wps_ap_priority_compar(wps_a, wps_b);
1104                 wpabuf_free(wps_a);
1105                 wpabuf_free(wps_b);
1106                 if (res)
1107                         return res;
1108         }
1109
1110         /*
1111          * Do not use current AP security policy as a sorting criteria during
1112          * WPS provisioning step since the AP may get reconfigured at the
1113          * completion of provisioning.
1114          */
1115
1116         /* all things being equal, use signal level; if signal levels are
1117          * identical, use quality values since some drivers may only report
1118          * that value and leave the signal level zero */
1119         if (wb->level == wa->level)
1120                 return wb->qual - wa->qual;
1121         return wb->level - wa->level;
1122 }
1123 #endif /* CONFIG_WPS */
1124
1125
1126 static void dump_scan_res(struct wpa_scan_results *scan_res)
1127 {
1128         size_t i;
1129
1130         if (scan_res->res == NULL || scan_res->num == 0)
1131                 return;
1132
1133         wpa_printf(MSG_EXCESSIVE, "Sorted scan results");
1134
1135         for (i = 0; i < scan_res->num; i++) {
1136                 struct wpa_scan_res *r = scan_res->res[i];
1137                 if ((r->flags & (WPA_SCAN_LEVEL_DBM | WPA_SCAN_NOISE_INVALID))
1138                     == WPA_SCAN_LEVEL_DBM) {
1139                         int snr = r->level - r->noise;
1140                         wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
1141                                    "noise=%d level=%d snr=%d%s flags=0x%x",
1142                                    MAC2STR(r->bssid), r->freq, r->qual,
1143                                    r->noise, r->level, snr,
1144                                    snr >= GREAT_SNR ? "*" : "", r->flags);
1145                 } else {
1146                         wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
1147                                    "noise=%d level=%d flags=0x%x",
1148                                    MAC2STR(r->bssid), r->freq, r->qual,
1149                                    r->noise, r->level, r->flags);
1150                 }
1151         }
1152 }
1153
1154
1155 /**
1156  * wpa_supplicant_get_scan_results - Get scan results
1157  * @wpa_s: Pointer to wpa_supplicant data
1158  * @info: Information about what was scanned or %NULL if not available
1159  * @new_scan: Whether a new scan was performed
1160  * Returns: Scan results, %NULL on failure
1161  *
1162  * This function request the current scan results from the driver and updates
1163  * the local BSS list wpa_s->bss. The caller is responsible for freeing the
1164  * results with wpa_scan_results_free().
1165  */
1166 struct wpa_scan_results *
1167 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
1168                                 struct scan_info *info, int new_scan)
1169 {
1170         struct wpa_scan_results *scan_res;
1171         size_t i;
1172         int (*compar)(const void *, const void *) = wpa_scan_result_compar;
1173
1174         scan_res = wpa_drv_get_scan_results2(wpa_s);
1175         if (scan_res == NULL) {
1176                 wpa_dbg(wpa_s, MSG_DEBUG, "Failed to get scan results");
1177                 return NULL;
1178         }
1179
1180 #ifdef CONFIG_WPS
1181         if (wpas_wps_in_progress(wpa_s)) {
1182                 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Order scan results with WPS "
1183                         "provisioning rules");
1184                 compar = wpa_scan_result_wps_compar;
1185         }
1186 #endif /* CONFIG_WPS */
1187
1188         qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
1189               compar);
1190         dump_scan_res(scan_res);
1191
1192         wpa_bss_update_start(wpa_s);
1193         for (i = 0; i < scan_res->num; i++)
1194                 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
1195         wpa_bss_update_end(wpa_s, info, new_scan);
1196
1197         return scan_res;
1198 }
1199
1200
1201 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
1202 {
1203         struct wpa_scan_results *scan_res;
1204         scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
1205         if (scan_res == NULL)
1206                 return -1;
1207         wpa_scan_results_free(scan_res);
1208
1209         return 0;
1210 }