scan.c revision c1ce337f7a9d8f8f1c1a1dbf2f68c1afa95bc2ab 
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	wpa_printf(MSG_DEBUG, "%s: scan_req = %d, ap_scan = %d", __func__,
96		wpa_s->scan_req, wpa_s->conf->ap_scan);
97
98	if (wpa_s->disconnected && !wpa_s->scan_req) {
99		wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
100		return;
101	}
102
103	if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
104	    !wpa_s->scan_req) {
105		wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
106		wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
107		return;
108	}
109	scan_req = wpa_s->scan_req;
110	wpa_s->scan_req = 0;
111
112	if (wpa_s->conf->ap_scan != 0 &&
113	    wpa_s->driver && IS_WIRED(wpa_s->driver)) {
114		wpa_printf(MSG_DEBUG, "Using wired authentication - "
115			   "overriding ap_scan configuration");
116		wpa_s->conf->ap_scan = 0;
117	}
118
119	if (wpa_s->conf->ap_scan == 0) {
120		wpa_supplicant_gen_assoc_event(wpa_s);
121		return;
122	}
123
124	if (wpa_s->wpa_state == WPA_DISCONNECTED ||
125	    wpa_s->wpa_state == WPA_INACTIVE)
126		wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
127
128	ssid = wpa_s->conf->ssid;
129	if (wpa_s->prev_scan_ssid != BROADCAST_SSID_SCAN) {
130		while (ssid) {
131			if (ssid == wpa_s->prev_scan_ssid) {
132				ssid = ssid->next;
133				break;
134			}
135			ssid = ssid->next;
136		}
137	}
138	while (ssid) {
139		if (!ssid->disabled &&
140		    (ssid->scan_ssid || wpa_s->conf->ap_scan == 2))
141			break;
142		ssid = ssid->next;
143	}
144
145	if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
146		/*
147		 * ap_scan=2 mode - try to associate with each SSID instead of
148		 * scanning for each scan_ssid=1 network.
149		 */
150		if (ssid == NULL) {
151			wpa_printf(MSG_DEBUG, "wpa_supplicant_scan: Reached "
152				   "end of scan list - go back to beginning");
153			wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
154			wpa_supplicant_req_scan(wpa_s, 0, 0);
155			return;
156		}
157		if (ssid->next) {
158			/* Continue from the next SSID on the next attempt. */
159			wpa_s->prev_scan_ssid = ssid;
160		} else {
161			/* Start from the beginning of the SSID list. */
162			wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
163		}
164		wpa_supplicant_associate(wpa_s, NULL, ssid);
165		return;
166	}
167
168#ifdef CONFIG_WPS
169	wps = wpas_wps_in_use(wpa_s->conf, &req_type);
170#endif /* CONFIG_WPS */
171
172	if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
173	    !wpa_s->use_client_mlme && wps != 2) {
174		wpa_s->scan_res_tried++;
175		wpa_s->scan_req = scan_req;
176		wpa_printf(MSG_DEBUG, "Trying to get current scan results "
177			   "first without requesting a new scan to speed up "
178			   "initial association");
179		wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
180		return;
181	}
182
183#ifdef CONFIG_WPS
184	if (wps) {
185		wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
186						wpa_s->wps->uuid, req_type);
187		if (wps_ie) {
188			extra_ie = wpabuf_head(wps_ie);
189			extra_ie_len = wpabuf_len(wps_ie);
190		}
191	}
192#endif /* CONFIG_WPS */
193
194	wpa_supplicant_notify_scanning(wpa_s, 1);
195
196	wpa_printf(MSG_DEBUG, "Starting AP scan (%s SSID)",
197		   ssid ? "specific": "broadcast");
198	if (ssid) {
199		wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
200				  ssid->ssid, ssid->ssid_len);
201		wpa_s->prev_scan_ssid = ssid;
202	} else
203		wpa_s->prev_scan_ssid = BROADCAST_SSID_SCAN;
204
205	if (wpa_s->use_client_mlme) {
206		ieee80211_sta_set_probe_req_ie(wpa_s, extra_ie, extra_ie_len);
207		ret = ieee80211_sta_req_scan(wpa_s, ssid ? ssid->ssid : NULL,
208					     ssid ? ssid->ssid_len : 0);
209	} else {
210		wpa_drv_set_probe_req_ie(wpa_s, extra_ie, extra_ie_len);
211		ret = wpa_drv_scan(wpa_s, &ssid);
212	}
213
214	wpabuf_free(wps_ie);
215
216	if (ret) {
217		wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
218		wpa_supplicant_notify_scanning(wpa_s, 0);
219		wpa_supplicant_req_scan(wpa_s, 10, 0);
220	} else {
221		wpa_s->scan_runs++;
222	}
223}
224
225
226/**
227 * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
228 * @wpa_s: Pointer to wpa_supplicant data
229 * @sec: Number of seconds after which to scan
230 * @usec: Number of microseconds after which to scan
231 *
232 * This function is used to schedule a scan for neighboring access points after
233 * the specified time.
234 */
235void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
236{
237#ifndef ANDROID
238	/* If there's at least one network that should be specifically scanned
239	 * then don't cancel the scan and reschedule.  Some drivers do
240	 * background scanning which generates frequent scan results, and that
241	 * causes the specific SSID scan to get continually pushed back and
242	 * never happen, which causes hidden APs to never get probe-scanned.
243	 */
244	if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
245	    wpa_s->conf->ap_scan == 1) {
246		struct wpa_ssid *ssid = wpa_s->conf->ssid;
247
248		while (ssid) {
249			if (!ssid->disabled && ssid->scan_ssid)
250				break;
251			ssid = ssid->next;
252		}
253		if (ssid) {
254			wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
255			        "ensure that specific SSID scans occur");
256			return;
257		}
258	}
259#endif
260
261	wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
262		sec, usec);
263	eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
264	eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
265}
266
267
268/**
269 * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
270 * @wpa_s: Pointer to wpa_supplicant data
271 *
272 * This function is used to cancel a scan request scheduled with
273 * wpa_supplicant_req_scan().
274 */
275void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
276{
277	wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
278	eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
279	wpa_supplicant_notify_scanning(wpa_s, 0);
280}
281
282
283void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
284				    int scanning)
285{
286	if (wpa_s->scanning != scanning) {
287		wpa_s->scanning = scanning;
288		wpa_supplicant_dbus_notify_scanning(wpa_s);
289	}
290}
291
292