aboutsummaryrefslogtreecommitdiffstats
path: root/wpa_supplicant/scan.c
blob: 56f062f56b42b01787858d71d039109ce1baf0cd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
/*
 * WPA Supplicant - Scanning
 * Copyright (c) 2003-2010, 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 "utils/includes.h"

#include "utils/common.h"
#include "utils/eloop.h"
#include "common/ieee802_11_defs.h"
#include "config.h"
#include "wpa_supplicant_i.h"
#include "driver_i.h"
#include "mlme.h"
#include "wps_supplicant.h"
#include "notify.h"
#include "bss.h"
#include "scan.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;
		if (wpa_s->current_ssid != NULL)
			wpas_notify_network_changed(wpa_s);
	}
	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,
			   enum wps_request_type *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 */


int wpa_supplicant_enabled_networks(struct wpa_config *conf)
{
	struct wpa_ssid *ssid = conf->ssid;
	while (ssid) {
		if (!ssid->disabled)
			return 1;
		ssid = ssid->next;
	}
	return 0;
}


static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
				     struct wpa_ssid *ssid)
{
	while (ssid) {
		if (!ssid->disabled)
			break;
		ssid = ssid->next;
	}

	/* ap_scan=2 mode - try to associate with each SSID. */
	if (ssid == NULL) {
		wpa_printf(MSG_DEBUG, "wpa_supplicant_scan: Reached "
			   "end of scan list - go back to beginning");
		wpa_s->prev_scan_ssid = WILDCARD_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 = WILDCARD_SSID_SCAN;
	}
	wpa_supplicant_associate(wpa_s, NULL, ssid);
}


static int int_array_len(const int *a)
{
	int i;
	for (i = 0; a && a[i]; i++)
		;
	return i;
}


static void int_array_concat(int **res, const int *a)
{
	int reslen, alen, i;
	int *n;

	reslen = int_array_len(*res);
	alen = int_array_len(a);

	n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
	if (n == NULL) {
		os_free(*res);
		*res = NULL;
		return;
	}
	for (i = 0; i <= alen; i++)
		n[reslen + i] = a[i];
	*res = n;
}


static int freq_cmp(const void *a, const void *b)
{
	int _a = *(int *) a;
	int _b = *(int *) b;

	if (_a == 0)
		return 1;
	if (_b == 0)
		return -1;
	return _a - _b;
}


static void int_array_sort_unique(int *a)
{
	int alen;
	int i, j;

	if (a == NULL)
		return;

	alen = int_array_len(a);
	qsort(a, alen, sizeof(int), freq_cmp);

	i = 0;
	j = 1;
	while (a[i] && a[j]) {
		if (a[i] == a[j]) {
			j++;
			continue;
		}
		a[++i] = a[j++];
	}
	if (a[i])
		i++;
	a[i] = 0;
}


int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
				struct wpa_driver_scan_params *params)
{
	int ret;

	wpa_supplicant_notify_scanning(wpa_s, 1);

	if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
		ret = ieee80211_sta_req_scan(wpa_s, params);
	else
		ret = wpa_drv_scan(wpa_s, params);

	if (ret) {
		wpa_supplicant_notify_scanning(wpa_s, 0);
		wpas_notify_scan_done(wpa_s, 0);
	} else
		wpa_s->scan_runs++;

	return ret;
}


static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
{
	struct wpa_supplicant *wpa_s = eloop_ctx;
	struct wpa_ssid *ssid;
	int scan_req = 0, ret;
	struct wpabuf *wps_ie = NULL;
	int wps = 0;
#ifdef CONFIG_WPS
	enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
#endif /* CONFIG_WPS */
	struct wpa_driver_scan_params params;
	size_t max_ssids;

	if (wpa_s->disconnected && !wpa_s->scan_req) {
		wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
		return;
	}

	if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
	    !wpa_s->scan_req) {
		wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
		wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
		return;
	}

	if (wpa_s->conf->ap_scan != 0 &&
	    (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
		wpa_printf(MSG_DEBUG, "Using wired authentication - "
			   "overriding ap_scan configuration");
		wpa_s->conf->ap_scan = 0;
		wpas_notify_ap_scan_changed(wpa_s);
	}

	if (wpa_s->conf->ap_scan == 0) {
		wpa_supplicant_gen_assoc_event(wpa_s);
		return;
	}

	if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
	    wpa_s->conf->ap_scan == 2)
		max_ssids = 1;
	else {
		max_ssids = wpa_s->max_scan_ssids;
		if (max_ssids > WPAS_MAX_SCAN_SSIDS)
			max_ssids = WPAS_MAX_SCAN_SSIDS;
	}

#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->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) &&
	    wps != 2) {
		wpa_s->scan_res_tried++;
		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;
	}

	scan_req = wpa_s->scan_req;
	wpa_s->scan_req = 0;

	os_memset(&params, 0, sizeof(params));

	if (wpa_s->wpa_state == WPA_DISCONNECTED ||
	    wpa_s->wpa_state == WPA_INACTIVE)
		wpa_supplicant_set_state(wpa_s, WPA_SCANNING);

	/* Find the starting point from which to continue scanning */
	ssid = wpa_s->conf->ssid;
	if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
		while (ssid) {
			if (ssid == wpa_s->prev_scan_ssid) {
				ssid = ssid->next;
				break;
			}
			ssid = ssid->next;
		}
	}

	if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
		wpa_supplicant_assoc_try(wpa_s, ssid);
		return;
	} else if (wpa_s->conf->ap_scan == 2) {
		/*
		 * User-initiated scan request in ap_scan == 2; scan with
		 * wildcard SSID.
		 */
		ssid = NULL;
	} else {
		struct wpa_ssid *start = ssid, *tssid;
		int freqs_set = 0;
		if (ssid == NULL && max_ssids > 1)
			ssid = wpa_s->conf->ssid;
		while (ssid) {
			if (!ssid->disabled && ssid->scan_ssid) {
				wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
						  ssid->ssid, ssid->ssid_len);
				params.ssids[params.num_ssids].ssid =
					ssid->ssid;
				params.ssids[params.num_ssids].ssid_len =
					ssid->ssid_len;
				params.num_ssids++;
				if (params.num_ssids + 1 >= max_ssids)
					break;
			}
			ssid = ssid->next;
			if (ssid == start)
				break;
			if (ssid == NULL && max_ssids > 1 &&
			    start != wpa_s->conf->ssid)
				ssid = wpa_s->conf->ssid;
		}

		for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
			if (tssid->disabled)
				continue;
			if ((params.freqs || !freqs_set) && tssid->scan_freq) {
				int_array_concat(&params.freqs,
						 tssid->scan_freq);
			} else {
				os_free(params.freqs);
				params.freqs = NULL;
			}
			freqs_set = 1;
		}
		int_array_sort_unique(params.freqs);
	}

	if (ssid) {
		wpa_s->prev_scan_ssid = ssid;
		if (max_ssids > 1) {
			wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
				   "scan request");
			params.num_ssids++;
		}
		wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
	} else {
		wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
		params.num_ssids++;
		wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
	}

#ifdef CONFIG_WPS
	if (wps) {
		wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
						wpa_s->wps->uuid, req_type);
		if (wps_ie) {
			params.extra_ies = wpabuf_head(wps_ie);
			params.extra_ies_len = wpabuf_len(wps_ie);
		}
	}
#endif /* CONFIG_WPS */

	ret = wpa_supplicant_trigger_scan(wpa_s, &params);

	wpabuf_free(wps_ie);
	os_free(params.freqs);

	if (ret) {
		wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
		wpa_supplicant_req_scan(wpa_s, 10, 0);
	} else
		wpa_s->scan_runs++;
}


/**
 * 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);
}


void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
				    int scanning)
{
	if (wpa_s->scanning != scanning) {
		wpa_s->scanning = scanning;
		wpas_notify_scanning(wpa_s);
	}
}


static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
{
	int rate = 0;
	const u8 *ie;
	int i;

	ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
	for (i = 0; ie && i < ie[1]; i++) {
		if ((ie[i + 2] & 0x7f) > rate)
			rate = ie[i + 2] & 0x7f;
	}

	ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
	for (i = 0; ie && i < ie[1]; i++) {
		if ((ie[i + 2] & 0x7f) > rate)
			rate = ie[i + 2] & 0x7f;
	}

	return rate;
}


const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
{
	const u8 *end, *pos;

	pos = (const u8 *) (res + 1);
	end = pos + res->ie_len;

	while (pos + 1 < end) {
		if (pos + 2 + pos[1] > end)
			break;
		if (pos[0] == ie)
			return pos;
		pos += 2 + pos[1];
	}

	return NULL;
}


const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
				  u32 vendor_type)
{
	const u8 *end, *pos;

	pos = (const u8 *) (res + 1);
	end = pos + res->ie_len;

	while (pos + 1 < end) {
		if (pos + 2 + pos[1] > end)
			break;
		if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
		    vendor_type == WPA_GET_BE32(&pos[2]))
			return pos;
		pos += 2 + pos[1];
	}

	return NULL;
}


struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
					     u32 vendor_type)
{
	struct wpabuf *buf;
	const u8 *end, *pos;

	buf = wpabuf_alloc(res->ie_len);
	if (buf == NULL)
		return NULL;

	pos = (const u8 *) (res + 1);
	end = pos + res->ie_len;

	while (pos + 1 < end) {
		if (pos + 2 + pos[1] > end)
			break;
		if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
		    vendor_type == WPA_GET_BE32(&pos[2]))
			wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
		pos += 2 + pos[1];
	}

	if (wpabuf_len(buf) == 0) {
		wpabuf_free(buf);
		buf = NULL;
	}

	return buf;
}


/* Compare function for sorting scan results. Return >0 if @b is considered
 * better. */
static int wpa_scan_result_compar(const void *a, const void *b)
{
	struct wpa_scan_res **_wa = (void *) a;
	struct wpa_scan_res **_wb = (void *) b;
	struct wpa_scan_res *wa = *_wa;
	struct wpa_scan_res *wb = *_wb;
	int wpa_a, wpa_b, maxrate_a, maxrate_b;

	/* WPA/WPA2 support preferred */
	wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
		wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
	wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
		wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;

	if (wpa_b && !wpa_a)
		return 1;
	if (!wpa_b && wpa_a)
		return -1;

	/* privacy support preferred */
	if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
	    (wb->caps & IEEE80211_CAP_PRIVACY))
		return 1;
	if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
	    (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
		return -1;

	/* best/max rate preferred if signal level close enough XXX */
	if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
	    (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
		maxrate_a = wpa_scan_get_max_rate(wa);
		maxrate_b = wpa_scan_get_max_rate(wb);
		if (maxrate_a != maxrate_b)
			return maxrate_b - maxrate_a;
	}

	/* use freq for channel preference */

	/* all things being equal, use signal level; if signal levels are
	 * identical, use quality values since some drivers may only report
	 * that value and leave the signal level zero */
	if (wb->level == wa->level)
		return wb->qual - wa->qual;
	return wb->level - wa->level;
}


/**
 * wpa_supplicant_get_scan_results - Get scan results
 * @wpa_s: Pointer to wpa_supplicant data
 * @info: Information about what was scanned or %NULL if not available
 * @new_scan: Whether a new scan was performed
 * Returns: Scan results, %NULL on failure
 *
 * This function request the current scan results from the driver and updates
 * the local BSS list wpa_s->bss. The caller is responsible for freeing the
 * results with wpa_scan_results_free().
 */
struct wpa_scan_results *
wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
				struct scan_info *info, int new_scan)
{
	struct wpa_scan_results *scan_res;
	size_t i;

	if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
		scan_res = ieee80211_sta_get_scan_results(wpa_s);
	else
		scan_res = wpa_drv_get_scan_results2(wpa_s);
	if (scan_res == NULL) {
		wpa_printf(MSG_DEBUG, "Failed to get scan results");
		return NULL;
	}

	qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
	      wpa_scan_result_compar);

	wpa_bss_update_start(wpa_s);
	for (i = 0; i < scan_res->num; i++)
		wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
	wpa_bss_update_end(wpa_s, info, new_scan);

	return scan_res;
}


int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
{
	struct wpa_scan_results *scan_res;
	scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
	if (scan_res == NULL)
		return -1;
	wpa_scan_results_free(scan_res);

	return 0;
}


void wpa_scan_results_free(struct wpa_scan_results *res)
{
	size_t i;

	if (res == NULL)
		return;

	for (i = 0; i < res->num; i++)
		os_free(res->res[i]);
	os_free(res->res);
	os_free(res);
}