git.maemo.org Git - wpasupplicant/blob - 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 "mlme.h"
  22 #include "wps_supplicant.h"
  23
  24
  25 static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
  26 {
  27         struct wpa_ssid *ssid;
  28         union wpa_event_data data;
  29
  30         ssid = wpa_supplicant_get_ssid(wpa_s);
  31         if (ssid == NULL)
  32                 return;
  33
  34         if (wpa_s->current_ssid == NULL)
  35                 wpa_s->current_ssid = ssid;
  36         wpa_supplicant_initiate_eapol(wpa_s);
  37         wpa_printf(MSG_DEBUG, "Already associated with a configured network - "
  38                    "generating associated event");
  39         os_memset(&data, 0, sizeof(data));
  40         wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);
  41 }
  42
  43
  44 #ifdef CONFIG_WPS
  45 static int wpas_wps_in_use(struct wpa_config *conf,
  46                            enum wps_request_type *req_type)
  47 {
  48         struct wpa_ssid *ssid;
  49         int wps = 0;
  50
  51         for (ssid = conf->ssid; ssid; ssid = ssid->next) {
  52                 if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
  53                         continue;
  54
  55                 wps = 1;
  56                 *req_type = wpas_wps_get_req_type(ssid);
  57                 if (!ssid->eap.phase1)
  58                         continue;
  59
  60                 if (os_strstr(ssid->eap.phase1, "pbc=1"))
  61                         return 2;
  62         }
  63
  64         return wps;
  65 }
  66 #endif /* CONFIG_WPS */
  67
  68
  69 static int wpa_supplicant_enabled_networks(struct wpa_config *conf)
  70 {
  71         struct wpa_ssid *ssid = conf->ssid;
  72         while (ssid) {
  73                 if (!ssid->disabled)
  74                         return 1;
  75                 ssid = ssid->next;
  76         }
  77         return 0;
  78 }
  79
  80
  81 static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
  82                                      struct wpa_ssid *ssid)
  83 {
  84         while (ssid) {
  85                 if (!ssid->disabled)
  86                         break;
  87                 ssid = ssid->next;
  88         }
  89
  90         /* ap_scan=2 mode - try to associate with each SSID. */
  91         if (ssid == NULL) {
  92                 wpa_printf(MSG_DEBUG, "wpa_supplicant_scan: Reached "
  93                            "end of scan list - go back to beginning");
  94                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
  95                 wpa_supplicant_req_scan(wpa_s, 0, 0);
  96                 return;
  97         }
  98         if (ssid->next) {
  99                 /* Continue from the next SSID on the next attempt. */
 100                 wpa_s->prev_scan_ssid = ssid;
 101         } else {
 102                 /* Start from the beginning of the SSID list. */
 103                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 104         }
 105         wpa_supplicant_associate(wpa_s, NULL, ssid);
 106 }
 107
 108
 109 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
 110 {
 111         struct wpa_supplicant *wpa_s = eloop_ctx;
 112         struct wpa_ssid *ssid;
 113         int scan_req = 0, ret;
 114         struct wpabuf *wps_ie = NULL;
 115         int wps = 0;
 116 #ifdef CONFIG_WPS
 117         enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
 118 #endif /* CONFIG_WPS */
 119         struct wpa_driver_scan_params params;
 120         size_t max_ssids;
 121
 122         if (wpa_s->disconnected && !wpa_s->scan_req)
 123                 return;
 124
 125         if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
 126             !wpa_s->scan_req) {
 127                 wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
 128                 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
 129                 return;
 130         }
 131
 132         if (wpa_s->conf->ap_scan != 0 &&
 133             (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
 134                 wpa_printf(MSG_DEBUG, "Using wired authentication - "
 135                            "overriding ap_scan configuration");
 136                 wpa_s->conf->ap_scan = 0;
 137         }
 138
 139         if (wpa_s->conf->ap_scan == 0) {
 140                 wpa_supplicant_gen_assoc_event(wpa_s);
 141                 return;
 142         }
 143
 144         if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
 145             wpa_s->conf->ap_scan == 2)
 146                 max_ssids = 1;
 147         else {
 148                 max_ssids = wpa_s->max_scan_ssids;
 149                 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
 150                         max_ssids = WPAS_MAX_SCAN_SSIDS;
 151         }
 152
 153 #ifdef CONFIG_WPS
 154         wps = wpas_wps_in_use(wpa_s->conf, &req_type);
 155 #endif /* CONFIG_WPS */
 156
 157         if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
 158             !(wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) &&
 159             wps != 2) {
 160                 wpa_s->scan_res_tried++;
 161                 wpa_printf(MSG_DEBUG, "Trying to get current scan results "
 162                            "first without requesting a new scan to speed up "
 163                            "initial association");
 164                 wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
 165                 return;
 166         }
 167
 168         scan_req = wpa_s->scan_req;
 169         wpa_s->scan_req = 0;
 170
 171         os_memset(&params, 0, sizeof(params));
 172
 173         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 174             wpa_s->wpa_state == WPA_INACTIVE)
 175                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 176
 177         /* Find the starting point from which to continue scanning */
 178         ssid = wpa_s->conf->ssid;
 179         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
 180                 while (ssid) {
 181                         if (ssid == wpa_s->prev_scan_ssid) {
 182                                 ssid = ssid->next;
 183                                 break;
 184                         }
 185                         ssid = ssid->next;
 186                 }
 187         }
 188
 189         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
 190                 wpa_supplicant_assoc_try(wpa_s, ssid);
 191                 return;
 192         } else if (wpa_s->conf->ap_scan == 2) {
 193                 /*
 194                  * User-initiated scan request in ap_scan == 2; scan with
 195                  * wildcard SSID.
 196                  */
 197                 ssid = NULL;
 198         } else {
 199                 struct wpa_ssid *start = ssid;
 200                 if (ssid == NULL && max_ssids > 1)
 201                         ssid = wpa_s->conf->ssid;
 202                 while (ssid) {
 203                         if (!ssid->disabled && ssid->scan_ssid) {
 204                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 205                                                   ssid->ssid, ssid->ssid_len);
 206                                 params.ssids[params.num_ssids].ssid =
 207                                         ssid->ssid;
 208                                 params.ssids[params.num_ssids].ssid_len =
 209                                         ssid->ssid_len;
 210                                 params.num_ssids++;
 211                                 if (params.num_ssids + 1 >= max_ssids)
 212                                         break;
 213                         }
 214                         ssid = ssid->next;
 215                         if (ssid == start)
 216                                 break;
 217                         if (ssid == NULL && max_ssids > 1 &&
 218                             start != wpa_s->conf->ssid)
 219                                 ssid = wpa_s->conf->ssid;
 220                 }
 221         }
 222
 223         if (ssid) {
 224                 wpa_s->prev_scan_ssid = ssid;
 225                 if (max_ssids > 1) {
 226                         wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
 227                                    "scan request");
 228                         params.num_ssids++;
 229                 }
 230                 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
 231         } else {
 232                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 233                 params.num_ssids++;
 234                 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
 235         }
 236
 237 #ifdef CONFIG_WPS
 238         if (wps) {
 239                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 240                                                 wpa_s->wps->uuid, req_type);
 241                 if (wps_ie) {
 242                         params.extra_ies = wpabuf_head(wps_ie);
 243                         params.extra_ies_len = wpabuf_len(wps_ie);
 244                 }
 245         }
 246 #endif /* CONFIG_WPS */
 247
 248         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) {
 249                 ieee80211_sta_set_probe_req_ie(wpa_s, params.extra_ies,
 250                                                params.extra_ies_len);
 251                 ret = ieee80211_sta_req_scan(wpa_s, params.ssids[0].ssid,
 252                                              params.ssids[0].ssid_len);
 253         } else {
 254                 wpa_drv_set_probe_req_ie(wpa_s, params.extra_ies,
 255                                          params.extra_ies_len);
 256                 ret = wpa_drv_scan(wpa_s, &params);
 257         }
 258
 259         wpabuf_free(wps_ie);
 260
 261         if (ret) {
 262                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
 263                 wpa_supplicant_req_scan(wpa_s, 10, 0);
 264         } else
 265                 wpa_s->scan_runs++;
 266 }
 267
 268
 269 /**
 270  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 271  * @wpa_s: Pointer to wpa_supplicant data
 272  * @sec: Number of seconds after which to scan
 273  * @usec: Number of microseconds after which to scan
 274  *
 275  * This function is used to schedule a scan for neighboring access points after
 276  * the specified time.
 277  */
 278 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 279 {
 280         /* If there's at least one network that should be specifically scanned
 281          * then don't cancel the scan and reschedule.  Some drivers do
 282          * background scanning which generates frequent scan results, and that
 283          * causes the specific SSID scan to get continually pushed back and
 284          * never happen, which causes hidden APs to never get probe-scanned.
 285          */
 286         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 287             wpa_s->conf->ap_scan == 1) {
 288                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 289
 290                 while (ssid) {
 291                         if (!ssid->disabled && ssid->scan_ssid)
 292                                 break;
 293                         ssid = ssid->next;
 294                 }
 295                 if (ssid) {
 296                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 297                                 "ensure that specific SSID scans occur");
 298                         return;
 299                 }
 300         }
 301
 302         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 303                 sec, usec);
 304         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 305         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 306 }
 307
 308
 309 /**
 310  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 311  * @wpa_s: Pointer to wpa_supplicant data
 312  *
 313  * This function is used to cancel a scan request scheduled with
 314  * wpa_supplicant_req_scan().
 315  */
 316 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 317 {
 318         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 319         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 320 }