wpa_supplicant/scan.c

   1 /*
   2  * WPA Supplicant - Scanning
   3  * Copyright (c) 2003-2008, 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 "includes.h"
  16
  17 #include "common.h"
  18 #include "eloop.h"
  19 #include "config.h"
  20 #include "wpa_supplicant_i.h"
  21 #include "driver_i.h"
  22 #include "mlme.h"
  23 #include "wps_supplicant.h"
  24 #include "notify.h"
  25
  26
  27 static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
  28 {
  29         struct wpa_ssid *ssid;
  30         union wpa_event_data data;
  31
  32         ssid = wpa_supplicant_get_ssid(wpa_s);
  33         if (ssid == NULL)
  34                 return;
  35
  36         if (wpa_s->current_ssid == NULL) {
  37                 wpa_s->current_ssid = ssid;
  38                 if (wpa_s->current_ssid != NULL)
  39                         wpas_notify_network_changed(wpa_s);
  40         }
  41         wpa_supplicant_initiate_eapol(wpa_s);
  42         wpa_printf(MSG_DEBUG, "Already associated with a configured network - "
  43                    "generating associated event");
  44         os_memset(&data, 0, sizeof(data));
  45         wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);
  46 }
  47
  48
  49 #ifdef CONFIG_WPS
  50 static int wpas_wps_in_use(struct wpa_config *conf,
  51                            enum wps_request_type *req_type)
  52 {
  53         struct wpa_ssid *ssid;
  54         int wps = 0;
  55
  56         for (ssid = conf->ssid; ssid; ssid = ssid->next) {
  57                 if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
  58                         continue;
  59
  60                 wps = 1;
  61                 *req_type = wpas_wps_get_req_type(ssid);
  62                 if (!ssid->eap.phase1)
  63                         continue;
  64
  65                 if (os_strstr(ssid->eap.phase1, "pbc=1"))
  66                         return 2;
  67         }
  68
  69         return wps;
  70 }
  71 #endif /* CONFIG_WPS */
  72
  73
  74 static int wpa_supplicant_enabled_networks(struct wpa_config *conf)
  75 {
  76         struct wpa_ssid *ssid = conf->ssid;
  77         while (ssid) {
  78                 if (!ssid->disabled)
  79                         return 1;
  80                 ssid = ssid->next;
  81         }
  82         return 0;
  83 }
  84
  85
  86 static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
  87                                      struct wpa_ssid *ssid)
  88 {
  89         while (ssid) {
  90                 if (!ssid->disabled)
  91                         break;
  92                 ssid = ssid->next;
  93         }
  94
  95         /* ap_scan=2 mode - try to associate with each SSID. */
  96         if (ssid == NULL) {
  97                 wpa_printf(MSG_DEBUG, "wpa_supplicant_scan: Reached "
  98                            "end of scan list - go back to beginning");
  99                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 100                 wpa_supplicant_req_scan(wpa_s, 0, 0);
 101                 return;
 102         }
 103         if (ssid->next) {
 104                 /* Continue from the next SSID on the next attempt. */
 105                 wpa_s->prev_scan_ssid = ssid;
 106         } else {
 107                 /* Start from the beginning of the SSID list. */
 108                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 109         }
 110         wpa_supplicant_associate(wpa_s, NULL, ssid);
 111 }
 112
 113
 114 static int int_array_len(const int *a)
 115 {
 116         int i;
 117         for (i = 0; a && a[i]; i++)
 118                 ;
 119         return i;
 120 }
 121
 122
 123 static void int_array_concat(int **res, const int *a)
 124 {
 125         int reslen, alen, i;
 126         int *n;
 127
 128         reslen = int_array_len(*res);
 129         alen = int_array_len(a);
 130
 131         n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
 132         if (n == NULL) {
 133                 os_free(*res);
 134                 *res = NULL;
 135         }
 136         for (i = 0; i <= alen; i++)
 137                 n[reslen + i] = a[i];
 138         *res = n;
 139 }
 140
 141
 142 static int freq_cmp(const void *a, const void *b)
 143 {
 144         int _a = *(int *) a;
 145         int _b = *(int *) b;
 146
 147         if (_a == 0)
 148                 return 1;
 149         if (_b == 0)
 150                 return -1;
 151         return _a - _b;
 152 }
 153
 154
 155 static void int_array_sort_unique(int *a)
 156 {
 157         int alen;
 158         int i, j;
 159
 160         if (a == NULL)
 161                 return;
 162
 163         alen = int_array_len(a);
 164         qsort(a, alen, sizeof(int), freq_cmp);
 165
 166         i = 0;
 167         j = 1;
 168         while (a[i] && a[j]) {
 169                 if (a[i] == a[j]) {
 170                         j++;
 171                         continue;
 172                 }
 173                 a[++i] = a[j++];
 174         }
 175         if (a[i])
 176                 i++;
 177         a[i] = 0;
 178 }
 179
 180
 181 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
 182 {
 183         struct wpa_supplicant *wpa_s = eloop_ctx;
 184         struct wpa_ssid *ssid;
 185         int scan_req = 0, ret;
 186         struct wpabuf *wps_ie = NULL;
 187         int wps = 0;
 188 #ifdef CONFIG_WPS
 189         enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
 190 #endif /* CONFIG_WPS */
 191         struct wpa_driver_scan_params params;
 192         size_t max_ssids;
 193
 194         if (wpa_s->disconnected && !wpa_s->scan_req) {
 195                 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
 196                 return;
 197         }
 198
 199         if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
 200             !wpa_s->scan_req) {
 201                 wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
 202                 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
 203                 return;
 204         }
 205
 206         if (wpa_s->conf->ap_scan != 0 &&
 207             (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
 208                 wpa_printf(MSG_DEBUG, "Using wired authentication - "
 209                            "overriding ap_scan configuration");
 210                 wpa_s->conf->ap_scan = 0;
 211                 wpas_notify_ap_scan_changed(wpa_s);
 212         }
 213
 214         if (wpa_s->conf->ap_scan == 0) {
 215                 wpa_supplicant_gen_assoc_event(wpa_s);
 216                 return;
 217         }
 218
 219         if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
 220             wpa_s->conf->ap_scan == 2)
 221                 max_ssids = 1;
 222         else {
 223                 max_ssids = wpa_s->max_scan_ssids;
 224                 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
 225                         max_ssids = WPAS_MAX_SCAN_SSIDS;
 226         }
 227
 228 #ifdef CONFIG_WPS
 229         wps = wpas_wps_in_use(wpa_s->conf, &req_type);
 230 #endif /* CONFIG_WPS */
 231
 232         if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
 233             !(wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) &&
 234             wps != 2) {
 235                 wpa_s->scan_res_tried++;
 236                 wpa_printf(MSG_DEBUG, "Trying to get current scan results "
 237                            "first without requesting a new scan to speed up "
 238                            "initial association");
 239                 wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
 240                 return;
 241         }
 242
 243         scan_req = wpa_s->scan_req;
 244         wpa_s->scan_req = 0;
 245
 246         os_memset(&params, 0, sizeof(params));
 247
 248         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 249             wpa_s->wpa_state == WPA_INACTIVE)
 250                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 251
 252         /* Find the starting point from which to continue scanning */
 253         ssid = wpa_s->conf->ssid;
 254         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
 255                 while (ssid) {
 256                         if (ssid == wpa_s->prev_scan_ssid) {
 257                                 ssid = ssid->next;
 258                                 break;
 259                         }
 260                         ssid = ssid->next;
 261                 }
 262         }
 263
 264         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
 265                 wpa_supplicant_assoc_try(wpa_s, ssid);
 266                 return;
 267         } else if (wpa_s->conf->ap_scan == 2) {
 268                 /*
 269                  * User-initiated scan request in ap_scan == 2; scan with
 270                  * wildcard SSID.
 271                  */
 272                 ssid = NULL;
 273         } else {
 274                 struct wpa_ssid *start = ssid;
 275                 int freqs_set = 0;
 276                 if (ssid == NULL && max_ssids > 1)
 277                         ssid = wpa_s->conf->ssid;
 278                 while (ssid) {
 279                         if (!ssid->disabled && ssid->scan_ssid) {
 280                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 281                                                   ssid->ssid, ssid->ssid_len);
 282                                 params.ssids[params.num_ssids].ssid =
 283                                         ssid->ssid;
 284                                 params.ssids[params.num_ssids].ssid_len =
 285                                         ssid->ssid_len;
 286                                 params.num_ssids++;
 287                                 if (params.num_ssids + 1 >= max_ssids)
 288                                         break;
 289                         }
 290                         ssid = ssid->next;
 291                         if (ssid == start)
 292                                 break;
 293                         if (ssid == NULL && max_ssids > 1 &&
 294                             start != wpa_s->conf->ssid)
 295                                 ssid = wpa_s->conf->ssid;
 296                 }
 297
 298                 for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
 299                         if (ssid->disabled)
 300                                 continue;
 301                         if ((params.freqs || !freqs_set) && ssid->scan_freq) {
 302                                 int_array_concat(&params.freqs,
 303                                                  ssid->scan_freq);
 304                         } else {
 305                                 os_free(params.freqs);
 306                                 params.freqs = NULL;
 307                         }
 308                         freqs_set = 1;
 309                 }
 310                 int_array_sort_unique(params.freqs);
 311         }
 312
 313         if (ssid) {
 314                 wpa_s->prev_scan_ssid = ssid;
 315                 if (max_ssids > 1) {
 316                         wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
 317                                    "scan request");
 318                         params.num_ssids++;
 319                 }
 320                 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
 321         } else {
 322                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 323                 params.num_ssids++;
 324                 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
 325         }
 326
 327 #ifdef CONFIG_WPS
 328         if (wps) {
 329                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 330                                                 wpa_s->wps->uuid, req_type);
 331                 if (wps_ie) {
 332                         params.extra_ies = wpabuf_head(wps_ie);
 333                         params.extra_ies_len = wpabuf_len(wps_ie);
 334                 }
 335         }
 336 #endif /* CONFIG_WPS */
 337
 338         wpa_supplicant_notify_scanning(wpa_s, 1);
 339
 340         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) {
 341                 ieee80211_sta_set_probe_req_ie(wpa_s, params.extra_ies,
 342                                                params.extra_ies_len);
 343                 ret = ieee80211_sta_req_scan(wpa_s, params.ssids[0].ssid,
 344                                              params.ssids[0].ssid_len);
 345         } else {
 346                 wpa_drv_set_probe_req_ie(wpa_s, params.extra_ies,
 347                                          params.extra_ies_len);
 348                 ret = wpa_drv_scan(wpa_s, &params);
 349         }
 350
 351         wpabuf_free(wps_ie);
 352         os_free(params.freqs);
 353
 354         if (ret) {
 355                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
 356                 wpa_supplicant_notify_scanning(wpa_s, 0);
 357                 wpas_notify_scan_done(wpa_s, 0);
 358                 wpa_supplicant_req_scan(wpa_s, 10, 0);
 359         } else
 360                 wpa_s->scan_runs++;
 361 }
 362
 363
 364 /**
 365  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 366  * @wpa_s: Pointer to wpa_supplicant data
 367  * @sec: Number of seconds after which to scan
 368  * @usec: Number of microseconds after which to scan
 369  *
 370  * This function is used to schedule a scan for neighboring access points after
 371  * the specified time.
 372  */
 373 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 374 {
 375         /* If there's at least one network that should be specifically scanned
 376          * then don't cancel the scan and reschedule.  Some drivers do
 377          * background scanning which generates frequent scan results, and that
 378          * causes the specific SSID scan to get continually pushed back and
 379          * never happen, which causes hidden APs to never get probe-scanned.
 380          */
 381         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 382             wpa_s->conf->ap_scan == 1) {
 383                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 384
 385                 while (ssid) {
 386                         if (!ssid->disabled && ssid->scan_ssid)
 387                                 break;
 388                         ssid = ssid->next;
 389                 }
 390                 if (ssid) {
 391                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 392                                 "ensure that specific SSID scans occur");
 393                         return;
 394                 }
 395         }
 396
 397         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 398                 sec, usec);
 399         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 400         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 401 }
 402
 403
 404 /**
 405  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 406  * @wpa_s: Pointer to wpa_supplicant data
 407  *
 408  * This function is used to cancel a scan request scheduled with
 409  * wpa_supplicant_req_scan().
 410  */
 411 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 412 {
 413         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 414         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 415 }
 416
 417
 418 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
 419                                     int scanning)
 420 {
 421         if (wpa_s->scanning != scanning) {
 422                 wpa_s->scanning = scanning;
 423                 wpas_notify_scanning(wpa_s);
 424         }
 425 }
 426