contrib/wpa_supplicant/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 #include "ctrl_iface_dbus.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 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_scan(void *eloop_ctx, void *timeout_ctx)
  83 {
  84         struct wpa_supplicant *wpa_s = eloop_ctx;
  85         struct wpa_ssid *ssid;
  86         int scan_req = 0, ret;
  87         struct wpabuf *wps_ie = NULL;
  88         const u8 *extra_ie = NULL;
  89         size_t extra_ie_len = 0;
  90         int wps = 0;
  91 #ifdef CONFIG_WPS
  92         enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
  93 #endif /* CONFIG_WPS */
  94
  95         if (wpa_s->disconnected && !wpa_s->scan_req) {
  96                 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
  97                 return;
  98         }
  99
 100         if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
 101             !wpa_s->scan_req) {
 102                 wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
 103                 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
 104                 return;
 105         }
 106         scan_req = wpa_s->scan_req;
 107         wpa_s->scan_req = 0;
 108
 109         if (wpa_s->conf->ap_scan != 0 &&
 110             wpa_s->driver && IS_WIRED(wpa_s->driver)) {
 111                 wpa_printf(MSG_DEBUG, "Using wired authentication - "
 112                            "overriding ap_scan configuration");
 113                 wpa_s->conf->ap_scan = 0;
 114         }
 115
 116         if (wpa_s->conf->ap_scan == 0) {
 117                 wpa_supplicant_gen_assoc_event(wpa_s);
 118                 return;
 119         }
 120
 121         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 122             wpa_s->wpa_state == WPA_INACTIVE)
 123                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 124
 125         ssid = wpa_s->conf->ssid;
 126         if (wpa_s->prev_scan_ssid != BROADCAST_SSID_SCAN) {
 127                 while (ssid) {
 128                         if (ssid == wpa_s->prev_scan_ssid) {
 129                                 ssid = ssid->next;
 130                                 break;
 131                         }
 132                         ssid = ssid->next;
 133                 }
 134         }
 135         while (ssid) {
 136                 if (!ssid->disabled &&
 137                     (ssid->scan_ssid || wpa_s->conf->ap_scan == 2))
 138                         break;
 139                 ssid = ssid->next;
 140         }
 141
 142         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
 143                 /*
 144                  * ap_scan=2 mode - try to associate with each SSID instead of
 145                  * scanning for each scan_ssid=1 network.
 146                  */
 147                 if (ssid == NULL) {
 148                         wpa_printf(MSG_DEBUG, "wpa_supplicant_scan: Reached "
 149                                    "end of scan list - go back to beginning");
 150                         wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
 151                         wpa_supplicant_req_scan(wpa_s, 0, 0);
 152                         return;
 153                 }
 154                 if (ssid->next) {
 155                         /* Continue from the next SSID on the next attempt. */
 156                         wpa_s->prev_scan_ssid = ssid;
 157                 } else {
 158                         /* Start from the beginning of the SSID list. */
 159                         wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
 160                 }
 161                 wpa_supplicant_associate(wpa_s, NULL, ssid);
 162                 return;
 163         }
 164
 165         wpa_printf(MSG_DEBUG, "Starting AP scan (%s SSID)",
 166                    ssid ? "specific": "broadcast");
 167         if (ssid) {
 168                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 169                                   ssid->ssid, ssid->ssid_len);
 170                 wpa_s->prev_scan_ssid = ssid;
 171         } else
 172                 wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
 173
 174 #ifdef CONFIG_WPS
 175         wps = wpas_wps_in_use(wpa_s->conf, &req_type);
 176 #endif /* CONFIG_WPS */
 177
 178         if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
 179             !wpa_s->use_client_mlme && wps != 2) {
 180                 wpa_s->scan_res_tried++;
 181                 wpa_s->scan_req = scan_req;
 182                 wpa_printf(MSG_DEBUG, "Trying to get current scan results "
 183                            "first without requesting a new scan to speed up "
 184                            "initial association");
 185                 wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
 186                 return;
 187         }
 188
 189 #ifdef CONFIG_WPS
 190         if (wps) {
 191                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 192                                                 wpa_s->wps->uuid, req_type);
 193                 if (wps_ie) {
 194                         extra_ie = wpabuf_head(wps_ie);
 195                         extra_ie_len = wpabuf_len(wps_ie);
 196                 }
 197         }
 198 #endif /* CONFIG_WPS */
 199
 200         wpa_supplicant_notify_scanning(wpa_s, 1);
 201
 202         if (wpa_s->use_client_mlme) {
 203                 ieee80211_sta_set_probe_req_ie(wpa_s, extra_ie, extra_ie_len);
 204                 ret = ieee80211_sta_req_scan(wpa_s, ssid ? ssid->ssid : NULL,
 205                                              ssid ? ssid->ssid_len : 0);
 206         } else {
 207                 wpa_drv_set_probe_req_ie(wpa_s, extra_ie, extra_ie_len);
 208                 ret = wpa_drv_scan(wpa_s, ssid ? ssid->ssid : NULL,
 209                                    ssid ? ssid->ssid_len : 0);
 210         }
 211
 212         wpabuf_free(wps_ie);
 213
 214         if (ret) {
 215                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
 216                 wpa_supplicant_notify_scanning(wpa_s, 0);
 217                 wpa_supplicant_req_scan(wpa_s, 10, 0);
 218         } else
 219                 wpa_s->scan_runs++;
 220 }
 221
 222
 223 /**
 224  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 225  * @wpa_s: Pointer to wpa_supplicant data
 226  * @sec: Number of seconds after which to scan
 227  * @usec: Number of microseconds after which to scan
 228  *
 229  * This function is used to schedule a scan for neighboring access points after
 230  * the specified time.
 231  */
 232 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 233 {
 234         /* If there's at least one network that should be specifically scanned
 235          * then don't cancel the scan and reschedule.  Some drivers do
 236          * background scanning which generates frequent scan results, and that
 237          * causes the specific SSID scan to get continually pushed back and
 238          * never happen, which causes hidden APs to never get probe-scanned.
 239          */
 240         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 241             wpa_s->conf->ap_scan == 1) {
 242                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 243
 244                 while (ssid) {
 245                         if (!ssid->disabled && ssid->scan_ssid)
 246                                 break;
 247                         ssid = ssid->next;
 248                 }
 249                 if (ssid) {
 250                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 251                                 "ensure that specific SSID scans occur");
 252                         return;
 253                 }
 254         }
 255
 256         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 257                 sec, usec);
 258         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 259         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 260 }
 261
 262
 263 /**
 264  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 265  * @wpa_s: Pointer to wpa_supplicant data
 266  *
 267  * This function is used to cancel a scan request scheduled with
 268  * wpa_supplicant_req_scan().
 269  */
 270 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 271 {
 272         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 273         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 274 }
 275
 276
 277 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
 278                                     int scanning)
 279 {
 280         if (wpa_s->scanning != scanning) {
 281                 wpa_s->scanning = scanning;
 282                 wpa_supplicant_dbus_notify_scanning(wpa_s);
 283         }
 284 }
 285