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 && wpa_s->drv_wired) {
 133                 wpa_printf(MSG_DEBUG, "Using wired authentication - "
 134                            "overriding ap_scan configuration");
 135                 wpa_s->conf->ap_scan = 0;
 136         }
 137
 138         if (wpa_s->conf->ap_scan == 0) {
 139                 wpa_supplicant_gen_assoc_event(wpa_s);
 140                 return;
 141         }
 142
 143         if (wpa_s->use_client_mlme || wpa_s->conf->ap_scan == 2)
 144                 max_ssids = 1;
 145         else {
 146                 max_ssids = wpa_s->max_scan_ssids;
 147                 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
 148                         max_ssids = WPAS_MAX_SCAN_SSIDS;
 149         }
 150
 151 #ifdef CONFIG_WPS
 152         wps = wpas_wps_in_use(wpa_s->conf, &req_type);
 153 #endif /* CONFIG_WPS */
 154
 155         if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
 156             !wpa_s->use_client_mlme && wps != 2) {
 157                 wpa_s->scan_res_tried++;
 158                 wpa_printf(MSG_DEBUG, "Trying to get current scan results "
 159                            "first without requesting a new scan to speed up "
 160                            "initial association");
 161                 wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
 162                 return;
 163         }
 164
 165         scan_req = wpa_s->scan_req;
 166         wpa_s->scan_req = 0;
 167
 168         os_memset(&params, 0, sizeof(params));
 169
 170         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 171             wpa_s->wpa_state == WPA_INACTIVE)
 172                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 173
 174         /* Find the starting point from which to continue scanning */
 175         ssid = wpa_s->conf->ssid;
 176         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
 177                 while (ssid) {
 178                         if (ssid == wpa_s->prev_scan_ssid) {
 179                                 ssid = ssid->next;
 180                                 break;
 181                         }
 182                         ssid = ssid->next;
 183                 }
 184         }
 185
 186         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
 187                 wpa_supplicant_assoc_try(wpa_s, ssid);
 188                 return;
 189         } else if (wpa_s->conf->ap_scan == 2) {
 190                 /*
 191                  * User-initiated scan request in ap_scan == 2; scan with
 192                  * wildcard SSID.
 193                  */
 194                 ssid = NULL;
 195         } else {
 196                 struct wpa_ssid *start = ssid;
 197                 if (ssid == NULL && max_ssids > 1)
 198                         ssid = wpa_s->conf->ssid;
 199                 while (ssid) {
 200                         if (!ssid->disabled && ssid->scan_ssid) {
 201                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 202                                                   ssid->ssid, ssid->ssid_len);
 203                                 params.ssids[params.num_ssids].ssid =
 204                                         ssid->ssid;
 205                                 params.ssids[params.num_ssids].ssid_len =
 206                                         ssid->ssid_len;
 207                                 params.num_ssids++;
 208                                 if (params.num_ssids + 1 >= max_ssids)
 209                                         break;
 210                         }
 211                         ssid = ssid->next;
 212                         if (ssid == start)
 213                                 break;
 214                         if (ssid == NULL && max_ssids > 1 &&
 215                             start != wpa_s->conf->ssid)
 216                                 ssid = wpa_s->conf->ssid;
 217                 }
 218         }
 219
 220         if (ssid) {
 221                 wpa_s->prev_scan_ssid = ssid;
 222                 if (max_ssids > 1) {
 223                         wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
 224                                    "scan request");
 225                         params.num_ssids++;
 226                 }
 227                 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
 228         } else {
 229                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
 230                 params.num_ssids++;
 231                 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
 232         }
 233
 234 #ifdef CONFIG_WPS
 235         if (wps) {
 236                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 237                                                 wpa_s->wps->uuid, req_type);
 238                 if (wps_ie) {
 239                         params.extra_ies = wpabuf_head(wps_ie);
 240                         params.extra_ies_len = wpabuf_len(wps_ie);
 241                 }
 242         }
 243 #endif /* CONFIG_WPS */
 244
 245         if (wpa_s->use_client_mlme) {
 246                 ieee80211_sta_set_probe_req_ie(wpa_s, params.extra_ies,
 247                                                params.extra_ies_len);
 248                 ret = ieee80211_sta_req_scan(wpa_s, params.ssids[0].ssid,
 249                                              params.ssids[0].ssid_len);
 250         } else {
 251                 wpa_drv_set_probe_req_ie(wpa_s, params.extra_ies,
 252                                          params.extra_ies_len);
 253                 ret = wpa_drv_scan(wpa_s, &params);
 254         }
 255
 256         wpabuf_free(wps_ie);
 257
 258         if (ret) {
 259                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
 260                 wpa_supplicant_req_scan(wpa_s, 10, 0);
 261         } else
 262                 wpa_s->scan_runs++;
 263 }
 264
 265
 266 /**
 267  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 268  * @wpa_s: Pointer to wpa_supplicant data
 269  * @sec: Number of seconds after which to scan
 270  * @usec: Number of microseconds after which to scan
 271  *
 272  * This function is used to schedule a scan for neighboring access points after
 273  * the specified time.
 274  */
 275 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 276 {
 277         /* If there's at least one network that should be specifically scanned
 278          * then don't cancel the scan and reschedule.  Some drivers do
 279          * background scanning which generates frequent scan results, and that
 280          * causes the specific SSID scan to get continually pushed back and
 281          * never happen, which causes hidden APs to never get probe-scanned.
 282          */
 283         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 284             wpa_s->conf->ap_scan == 1) {
 285                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 286
 287                 while (ssid) {
 288                         if (!ssid->disabled && ssid->scan_ssid)
 289                                 break;
 290                         ssid = ssid->next;
 291                 }
 292                 if (ssid) {
 293                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 294                                 "ensure that specific SSID scans occur");
 295                         return;
 296                 }
 297         }
 298
 299         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 300                 sec, usec);
 301         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 302         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 303 }
 304
 305
 306 /**
 307  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 308  * @wpa_s: Pointer to wpa_supplicant data
 309  *
 310  * This function is used to cancel a scan request scheduled with
 311  * wpa_supplicant_req_scan().
 312  */
 313 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 314 {
 315         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 316         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 317 }