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 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
  69 {
  70         struct wpa_supplicant *wpa_s = eloop_ctx;
  71         struct wpa_ssid *ssid;
  72         int enabled, scan_req = 0, ret;
  73         struct wpabuf *wps_ie = NULL;
  74         const u8 *extra_ie = NULL;
  75         size_t extra_ie_len = 0;
  76         int wps = 0;
  77 #ifdef CONFIG_WPS
  78         enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
  79 #endif /* CONFIG_WPS */
  80
  81         if (wpa_s->disconnected && !wpa_s->scan_req)
  82                 return;
  83
  84         enabled = 0;
  85         ssid = wpa_s->conf->ssid;
  86         while (ssid) {
  87                 if (!ssid->disabled) {
  88                         enabled++;
  89                         break;
  90                 }
  91                 ssid = ssid->next;
  92         }
  93         if (!enabled && !wpa_s->scan_req) {
  94                 wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
  95                 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
  96                 return;
  97         }
  98         scan_req = wpa_s->scan_req;
  99         wpa_s->scan_req = 0;
 100
 101         if (wpa_s->conf->ap_scan != 0 &&
 102             wpa_s->driver && IS_WIRED(wpa_s->driver)) {
 103                 wpa_printf(MSG_DEBUG, "Using wired authentication - "
 104                            "overriding ap_scan configuration");
 105                 wpa_s->conf->ap_scan = 0;
 106         }
 107
 108         if (wpa_s->conf->ap_scan == 0) {
 109                 wpa_supplicant_gen_assoc_event(wpa_s);
 110                 return;
 111         }
 112
 113         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 114             wpa_s->wpa_state == WPA_INACTIVE)
 115                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
 116
 117         ssid = wpa_s->conf->ssid;
 118         if (wpa_s->prev_scan_ssid != BROADCAST_SSID_SCAN) {
 119                 while (ssid) {
 120                         if (ssid == wpa_s->prev_scan_ssid) {
 121                                 ssid = ssid->next;
 122                                 break;
 123                         }
 124                         ssid = ssid->next;
 125                 }
 126         }
 127         while (ssid) {
 128                 if (!ssid->disabled &&
 129                     (ssid->scan_ssid || wpa_s->conf->ap_scan == 2))
 130                         break;
 131                 ssid = ssid->next;
 132         }
 133
 134         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
 135                 /*
 136                  * ap_scan=2 mode - try to associate with each SSID instead of
 137                  * scanning for each scan_ssid=1 network.
 138                  */
 139                 if (ssid == NULL) {
 140                         wpa_printf(MSG_DEBUG, "wpa_supplicant_scan: Reached "
 141                                    "end of scan list - go back to beginning");
 142                         wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
 143                         wpa_supplicant_req_scan(wpa_s, 0, 0);
 144                         return;
 145                 }
 146                 if (ssid->next) {
 147                         /* Continue from the next SSID on the next attempt. */
 148                         wpa_s->prev_scan_ssid = ssid;
 149                 } else {
 150                         /* Start from the beginning of the SSID list. */
 151                         wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
 152                 }
 153                 wpa_supplicant_associate(wpa_s, NULL, ssid);
 154                 return;
 155         }
 156
 157         wpa_printf(MSG_DEBUG, "Starting AP scan (%s SSID)",
 158                    ssid ? "specific": "broadcast");
 159         if (ssid) {
 160                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
 161                                   ssid->ssid, ssid->ssid_len);
 162                 wpa_s->prev_scan_ssid = ssid;
 163         } else
 164                 wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
 165
 166 #ifdef CONFIG_WPS
 167         wps = wpas_wps_in_use(wpa_s->conf, &req_type);
 168 #endif /* CONFIG_WPS */
 169
 170         if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
 171             !wpa_s->use_client_mlme && wps != 2) {
 172                 wpa_s->scan_res_tried++;
 173                 wpa_s->scan_req = scan_req;
 174                 wpa_printf(MSG_DEBUG, "Trying to get current scan results "
 175                            "first without requesting a new scan to speed up "
 176                            "initial association");
 177                 wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
 178                 return;
 179         }
 180
 181 #ifdef CONFIG_WPS
 182         if (wps) {
 183                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
 184                                                 wpa_s->wps->uuid, req_type);
 185                 if (wps_ie) {
 186                         extra_ie = wpabuf_head(wps_ie);
 187                         extra_ie_len = wpabuf_len(wps_ie);
 188                 }
 189         }
 190 #endif /* CONFIG_WPS */
 191
 192         if (wpa_s->use_client_mlme) {
 193                 ieee80211_sta_set_probe_req_ie(wpa_s, extra_ie, extra_ie_len);
 194                 ret = ieee80211_sta_req_scan(wpa_s, ssid ? ssid->ssid : NULL,
 195                                              ssid ? ssid->ssid_len : 0);
 196         } else {
 197                 wpa_drv_set_probe_req_ie(wpa_s, extra_ie, extra_ie_len);
 198                 ret = wpa_drv_scan(wpa_s, ssid ? ssid->ssid : NULL,
 199                                    ssid ? ssid->ssid_len : 0);
 200         }
 201
 202         wpabuf_free(wps_ie);
 203
 204         if (ret) {
 205                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
 206                 wpa_supplicant_req_scan(wpa_s, 10, 0);
 207         } else
 208                 wpa_s->scan_runs++;
 209 }
 210
 211
 212 /**
 213  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
 214  * @wpa_s: Pointer to wpa_supplicant data
 215  * @sec: Number of seconds after which to scan
 216  * @usec: Number of microseconds after which to scan
 217  *
 218  * This function is used to schedule a scan for neighboring access points after
 219  * the specified time.
 220  */
 221 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 222 {
 223         /* If there's at least one network that should be specifically scanned
 224          * then don't cancel the scan and reschedule.  Some drivers do
 225          * background scanning which generates frequent scan results, and that
 226          * causes the specific SSID scan to get continually pushed back and
 227          * never happen, which causes hidden APs to never get probe-scanned.
 228          */
 229         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
 230             wpa_s->conf->ap_scan == 1) {
 231                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
 232
 233                 while (ssid) {
 234                         if (!ssid->disabled && ssid->scan_ssid)
 235                                 break;
 236                         ssid = ssid->next;
 237                 }
 238                 if (ssid) {
 239                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
 240                                 "ensure that specific SSID scans occur");
 241                         return;
 242                 }
 243         }
 244
 245         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
 246                 sec, usec);
 247         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 248         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
 249 }
 250
 251
 252 /**
 253  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
 254  * @wpa_s: Pointer to wpa_supplicant data
 255  *
 256  * This function is used to cancel a scan request scheduled with
 257  * wpa_supplicant_req_scan().
 258  */
 259 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
 260 {
 261         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
 262         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
 263 }