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 = BROADCAST_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 = BROADCAST_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->driver && IS_WIRED(wpa_s->driver)) {
 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->use_client_mlme || wpa_s->conf->ap_scan == 2)
 145                 max_ssids = 1;
 146         else {
 147                 max_ssids = wpa_s->max_scan_ssids;
 148                 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
 149                         max_ssids = WPAS_MAX_SCAN_SSIDS;
 150         }
 151
 152 #ifdef CONFIG_WPS
 153         wps = wpas_wps_in_use(wpa_s->conf, &req_type);
 154 #endif /* CONFIG_WPS */
 155
 156         if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
 157             !wpa_s->use_client_mlme && wps != 2) {
 158                 wpa_s->scan_res_tried++;
 159                 wpa_printf(MSG_DEBUG, "Trying to get current scan results "
 160                            "first without requesting a new scan to speed up "
 161                            "initial association");
 162                 wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
 163                 return;
 164         }
 165
 166         scan_req = wpa_s->scan_req;
 167         wpa_s->scan_req = 0;
 168
 169         os_memset(&params, 0, sizeof(params));
 170
 171         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 172             wpa_s->wpa_state == WPA_INACTIVE)
 173                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 174
 175         /* Find the starting point from which to continue scanning */
 176         ssid = wpa_s->conf->ssid;
 177         if (wpa_s->prev_scan_ssid != BROADCAST_SSID_SCAN) {
 178                 while (ssid) {
 179                         if (ssid == wpa_s->prev_scan_ssid) {
 180                                 ssid = ssid->next;
 181                                 break;
 182                         }
 183                         ssid = ssid->next;
 184                 }
 185         }
 186
 187         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
 188                 wpa_supplicant_assoc_try(wpa_s, ssid);
 189                 return;
 190         } else if (wpa_s->conf->ap_scan == 2) {
 191                 /*
 192                  * User-initiated scan request in ap_scan == 2; use broadcast
 193                  * scan.
 194                  */
 195                 ssid = NULL;
 196         } else {
 197                 struct wpa_ssid *start = ssid;
 198                 if (ssid == NULL && max_ssids > 1)
 199                         ssid = wpa_s->conf->ssid;
 200                 while (ssid) {
 201                         if (!ssid->disabled && ssid->scan_ssid) {
 202                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 203                                                   ssid->ssid, ssid->ssid_len);
 204                                 params.ssids[params.num_ssids].ssid =
 205                                         ssid->ssid;
 206                                 params.ssids[params.num_ssids].ssid_len =
 207                                         ssid->ssid_len;
 208                                 params.num_ssids++;
 209                                 if (params.num_ssids + 1 >= max_ssids)
 210                                         break;
 211                         }
 212                         ssid = ssid->next;
 213                         if (ssid == start)
 214                                 break;
 215                         if (ssid == NULL && max_ssids > 1 &&
 216                             start != wpa_s->conf->ssid)
 217                                 ssid = wpa_s->conf->ssid;
 218                 }
 219         }
 220
 221         if (ssid) {
 222                 wpa_s->prev_scan_ssid = ssid;
 223                 if (max_ssids > 1) {
 224                         wpa_printf(MSG_DEBUG, "Include broadcast SSID in the "
 225                                    "scan request");
 226                         params.num_ssids++; /* Broadcast scan */
 227                 }
 228                 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
 229         } else {
 230                 wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
 231                 params.num_ssids++;
 232                 wpa_printf(MSG_DEBUG, "Starting AP scan for broadcast SSID");
 233         }
 234
 235 #ifdef CONFIG_WPS
 236         if (wps) {
 237                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 238                                                 wpa_s->wps->uuid, req_type);
 239                 if (wps_ie) {
 240                         params.extra_ies = wpabuf_head(wps_ie);
 241                         params.extra_ies_len = wpabuf_len(wps_ie);
 242                 }
 243         }
 244 #endif /* CONFIG_WPS */
 245
 246         if (wpa_s->use_client_mlme) {
 247                 ieee80211_sta_set_probe_req_ie(wpa_s, params.extra_ies,
 248                                                params.extra_ies_len);
 249                 ret = ieee80211_sta_req_scan(wpa_s, params.ssids[0].ssid,
 250                                              params.ssids[0].ssid_len);
 251         } else {
 252                 wpa_drv_set_probe_req_ie(wpa_s, params.extra_ies,
 253                                          params.extra_ies_len);
 254                 ret = wpa_drv_scan(wpa_s, &params);
 255         }
 256
 257         wpabuf_free(wps_ie);
 258
 259         if (ret) {
 260                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
 261                 wpa_supplicant_req_scan(wpa_s, 10, 0);
 262         } else
 263                 wpa_s->scan_runs++;
 264 }
 265
 266
 267 /**
 268  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 269  * @wpa_s: Pointer to wpa_supplicant data
 270  * @sec: Number of seconds after which to scan
 271  * @usec: Number of microseconds after which to scan
 272  *
 273  * This function is used to schedule a scan for neighboring access points after
 274  * the specified time.
 275  */
 276 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 277 {
 278         /* If there's at least one network that should be specifically scanned
 279          * then don't cancel the scan and reschedule.  Some drivers do
 280          * background scanning which generates frequent scan results, and that
 281          * causes the specific SSID scan to get continually pushed back and
 282          * never happen, which causes hidden APs to never get probe-scanned.
 283          */
 284         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 285             wpa_s->conf->ap_scan == 1) {
 286                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 287
 288                 while (ssid) {
 289                         if (!ssid->disabled && ssid->scan_ssid)
 290                                 break;
 291                         ssid = ssid->next;
 292                 }
 293                 if (ssid) {
 294                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 295                                 "ensure that specific SSID scans occur");
 296                         return;
 297                 }
 298         }
 299
 300         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 301                 sec, usec);
 302         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 303         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 304 }
 305
 306
 307 /**
 308  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 309  * @wpa_s: Pointer to wpa_supplicant data
 310  *
 311  * This function is used to cancel a scan request scheduled with
 312  * wpa_supplicant_req_scan().
 313  */
 314 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 315 {
 316         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 317         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 318 }