hostap/wpa_supplicant/scan.c

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/*
* WPA Supplicant - Scanning
* Copyright (c) 2003-2008, Jouni Malinen <j@w1.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
#include "includes.h"
#include "common.h"
#include "eloop.h"
#include "config.h"
#include "wpa_supplicant_i.h"
#include "mlme.h"
#include "wps/wps.h"
#include "wps_supplicant.h"
static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
{
struct wpa_ssid *ssid;
union wpa_event_data data;
ssid = wpa_supplicant_get_ssid(wpa_s);
if (ssid == NULL)
return;
if (wpa_s->current_ssid == NULL)
wpa_s->current_ssid = ssid;
wpa_supplicant_initiate_eapol(wpa_s);
wpa_printf(MSG_DEBUG, "Already associated with a configured network - "
"generating associated event");
os_memset(&data, 0, sizeof(data));
wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);
}
#ifdef CONFIG_WPS
static int wpas_wps_in_use(struct wpa_config *conf, u8 *req_type)
{
struct wpa_ssid *ssid;
int wps = 0;
for (ssid = conf->ssid; ssid; ssid = ssid->next) {
if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
continue;
wps = 1;
*req_type = wpas_wps_get_req_type(ssid);
if (!ssid->eap.phase1)
continue;
if (os_strstr(ssid->eap.phase1, "pbc=1"))
return 2;
}
return wps;
}
#endif /* CONFIG_WPS */
static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
{
struct wpa_supplicant *wpa_s = eloop_ctx;
struct wpa_ssid *ssid;
int enabled, scan_req = 0, ret;
struct wpabuf *wps_ie = NULL;
const u8 *extra_ie = NULL;
size_t extra_ie_len = 0;
int wps = 0;
#ifdef CONFIG_WPS
u8 req_type = 0;
#endif /* CONFIG_WPS */
if (wpa_s->disconnected && !wpa_s->scan_req)
return;
enabled = 0;
ssid = wpa_s->conf->ssid;
while (ssid) {
if (!ssid->disabled) {
enabled++;
break;
}
ssid = ssid->next;
}
if (!enabled && !wpa_s->scan_req) {
wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
return;
}
scan_req = wpa_s->scan_req;
wpa_s->scan_req = 0;
if (wpa_s->conf->ap_scan != 0 &&
wpa_s->driver && IS_WIRED(wpa_s->driver)) {
wpa_printf(MSG_DEBUG, "Using wired authentication - "
"overriding ap_scan configuration");
wpa_s->conf->ap_scan = 0;
}
if (wpa_s->conf->ap_scan == 0) {
wpa_supplicant_gen_assoc_event(wpa_s);
return;
}
if (wpa_s->wpa_state == WPA_DISCONNECTED ||
wpa_s->wpa_state == WPA_INACTIVE)
wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
ssid = wpa_s->conf->ssid;
if (wpa_s->prev_scan_ssid != BROADCAST_SSID_SCAN) {
while (ssid) {
if (ssid == wpa_s->prev_scan_ssid) {
ssid = ssid->next;
break;
}
ssid = ssid->next;
}
}
while (ssid) {
if (!ssid->disabled &&
(ssid->scan_ssid || wpa_s->conf->ap_scan == 2))
break;
ssid = ssid->next;
}
if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
/*
* ap_scan=2 mode - try to associate with each SSID instead of
* scanning for each scan_ssid=1 network.
*/
if (ssid == NULL) {
wpa_printf(MSG_DEBUG, "wpa_supplicant_scan: Reached "
"end of scan list - go back to beginning");
wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
wpa_supplicant_req_scan(wpa_s, 0, 0);
return;
}
if (ssid->next) {
/* Continue from the next SSID on the next attempt. */
wpa_s->prev_scan_ssid = ssid;
} else {
/* Start from the beginning of the SSID list. */
wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
}
wpa_supplicant_associate(wpa_s, NULL, ssid);
return;
}
wpa_printf(MSG_DEBUG, "Starting AP scan (%s SSID)",
ssid ? "specific": "broadcast");
if (ssid) {
wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
ssid->ssid, ssid->ssid_len);
wpa_s->prev_scan_ssid = ssid;
} else
wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
#ifdef CONFIG_WPS
wps = wpas_wps_in_use(wpa_s->conf, &req_type);
#endif /* CONFIG_WPS */
if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
!wpa_s->use_client_mlme && wps != 2) {
wpa_s->scan_res_tried++;
wpa_s->scan_req = scan_req;
wpa_printf(MSG_DEBUG, "Trying to get current scan results "
"first without requesting a new scan to speed up "
"initial association");
wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
return;
}
#ifdef CONFIG_WPS
if (wps) {
wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
wpa_s->conf->uuid, req_type);
if (wps_ie) {
extra_ie = wpabuf_head(wps_ie);
extra_ie_len = wpabuf_len(wps_ie);
}
}
#endif /* CONFIG_WPS */
if (wpa_s->use_client_mlme) {
ieee80211_sta_set_probe_req_ie(wpa_s, extra_ie, extra_ie_len);
ret = ieee80211_sta_req_scan(wpa_s, ssid ? ssid->ssid : NULL,
ssid ? ssid->ssid_len : 0);
} else {
wpa_drv_set_probe_req_ie(wpa_s, extra_ie, extra_ie_len);
ret = wpa_drv_scan(wpa_s, ssid ? ssid->ssid : NULL,
ssid ? ssid->ssid_len : 0);
}
wpabuf_free(wps_ie);
if (ret) {
wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
wpa_supplicant_req_scan(wpa_s, 10, 0);
}
}
/**
* wpa_supplicant_req_scan - Schedule a scan for neighboring access points
* @wpa_s: Pointer to wpa_supplicant data
* @sec: Number of seconds after which to scan
* @usec: Number of microseconds after which to scan
*
* This function is used to schedule a scan for neighboring access points after
* the specified time.
*/
void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
{
/* If there's at least one network that should be specifically scanned
* then don't cancel the scan and reschedule. Some drivers do
* background scanning which generates frequent scan results, and that
* causes the specific SSID scan to get continually pushed back and
* never happen, which causes hidden APs to never get probe-scanned.
*/
if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
wpa_s->conf->ap_scan == 1) {
struct wpa_ssid *ssid = wpa_s->conf->ssid;
while (ssid) {
if (!ssid->disabled && ssid->scan_ssid)
break;
ssid = ssid->next;
}
if (ssid) {
wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
"ensure that specific SSID scans occur");
return;
}
}
wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
sec, usec);
eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
}
/**
* wpa_supplicant_cancel_scan - Cancel a scheduled scan request
* @wpa_s: Pointer to wpa_supplicant data
*
* This function is used to cancel a scan request scheduled with
* wpa_supplicant_req_scan().
*/
void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
{
wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
}