scan.c revision 02304a41d4807a728b67d2efc7db0f85722640c8 
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
26static 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
46static 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
70int 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
82static 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/**
225 * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
226 * @wpa_s: Pointer to wpa_supplicant data
227 * @sec: Number of seconds after which to scan
228 * @usec: Number of microseconds after which to scan
229 *
230 * This function is used to schedule a scan for neighboring access points after
231 * the specified time.
232 */
233void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
234{
235#ifndef ANDROID
236	/* If there's at least one network that should be specifically scanned
237	 * then don't cancel the scan and reschedule.  Some drivers do
238	 * background scanning which generates frequent scan results, and that
239	 * causes the specific SSID scan to get continually pushed back and
240	 * never happen, which causes hidden APs to never get probe-scanned.
241	 */
242	if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
243	    wpa_s->conf->ap_scan == 1) {
244		struct wpa_ssid *ssid = wpa_s->conf->ssid;
245
246		while (ssid) {
247			if (!ssid->disabled && ssid->scan_ssid)
248				break;
249			ssid = ssid->next;
250		}
251		if (ssid) {
252			wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
253			        "ensure that specific SSID scans occur");
254			return;
255		}
256	}
257#endif
258
259	wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
260		sec, usec);
261	eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
262	eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
263}
264
265
266/**
267 * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
268 * @wpa_s: Pointer to wpa_supplicant data
269 *
270 * This function is used to cancel a scan request scheduled with
271 * wpa_supplicant_req_scan().
272 */
273void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
274{
275	wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
276	eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
277	wpa_supplicant_notify_scanning(wpa_s, 0);
278}
279
280
281void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
282				    int scanning)
283{
284	if (wpa_s->scanning != scanning) {
285		wpa_s->scanning = scanning;
286		wpa_supplicant_dbus_notify_scanning(wpa_s);
287	}
288}
289
290