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