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[FreeBSD/releng/9.2.git] / contrib / wpa / wpa_supplicant / scan.c
1 /*
2  * WPA Supplicant - Scanning
3  * Copyright (c) 2003-2010, 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 "utils/includes.h"
16
17 #include "utils/common.h"
18 #include "utils/eloop.h"
19 #include "common/ieee802_11_defs.h"
20 #include "config.h"
21 #include "wpa_supplicant_i.h"
22 #include "driver_i.h"
23 #include "mlme.h"
24 #include "wps_supplicant.h"
25 #include "notify.h"
26 #include "bss.h"
27 #include "scan.h"
28
29
30 static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
31 {
32         struct wpa_ssid *ssid;
33         union wpa_event_data data;
34
35         ssid = wpa_supplicant_get_ssid(wpa_s);
36         if (ssid == NULL)
37                 return;
38
39         if (wpa_s->current_ssid == NULL) {
40                 wpa_s->current_ssid = ssid;
41                 if (wpa_s->current_ssid != NULL)
42                         wpas_notify_network_changed(wpa_s);
43         }
44         wpa_supplicant_initiate_eapol(wpa_s);
45         wpa_printf(MSG_DEBUG, "Already associated with a configured network - "
46                    "generating associated event");
47         os_memset(&data, 0, sizeof(data));
48         wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);
49 }
50
51
52 #ifdef CONFIG_WPS
53 static int wpas_wps_in_use(struct wpa_config *conf,
54                            enum wps_request_type *req_type)
55 {
56         struct wpa_ssid *ssid;
57         int wps = 0;
58
59         for (ssid = conf->ssid; ssid; ssid = ssid->next) {
60                 if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
61                         continue;
62
63                 wps = 1;
64                 *req_type = wpas_wps_get_req_type(ssid);
65                 if (!ssid->eap.phase1)
66                         continue;
67
68                 if (os_strstr(ssid->eap.phase1, "pbc=1"))
69                         return 2;
70         }
71
72         return wps;
73 }
74 #endif /* CONFIG_WPS */
75
76
77 int wpa_supplicant_enabled_networks(struct wpa_config *conf)
78 {
79         struct wpa_ssid *ssid = conf->ssid;
80         while (ssid) {
81                 if (!ssid->disabled)
82                         return 1;
83                 ssid = ssid->next;
84         }
85         return 0;
86 }
87
88
89 static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
90                                      struct wpa_ssid *ssid)
91 {
92         while (ssid) {
93                 if (!ssid->disabled)
94                         break;
95                 ssid = ssid->next;
96         }
97
98         /* ap_scan=2 mode - try to associate with each SSID. */
99         if (ssid == NULL) {
100                 wpa_printf(MSG_DEBUG, "wpa_supplicant_scan: Reached "
101                            "end of scan list - go back to beginning");
102                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
103                 wpa_supplicant_req_scan(wpa_s, 0, 0);
104                 return;
105         }
106         if (ssid->next) {
107                 /* Continue from the next SSID on the next attempt. */
108                 wpa_s->prev_scan_ssid = ssid;
109         } else {
110                 /* Start from the beginning of the SSID list. */
111                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
112         }
113         wpa_supplicant_associate(wpa_s, NULL, ssid);
114 }
115
116
117 static int int_array_len(const int *a)
118 {
119         int i;
120         for (i = 0; a && a[i]; i++)
121                 ;
122         return i;
123 }
124
125
126 static void int_array_concat(int **res, const int *a)
127 {
128         int reslen, alen, i;
129         int *n;
130
131         reslen = int_array_len(*res);
132         alen = int_array_len(a);
133
134         n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
135         if (n == NULL) {
136                 os_free(*res);
137                 *res = NULL;
138                 return;
139         }
140         for (i = 0; i <= alen; i++)
141                 n[reslen + i] = a[i];
142         *res = n;
143 }
144
145
146 static int freq_cmp(const void *a, const void *b)
147 {
148         int _a = *(int *) a;
149         int _b = *(int *) b;
150
151         if (_a == 0)
152                 return 1;
153         if (_b == 0)
154                 return -1;
155         return _a - _b;
156 }
157
158
159 static void int_array_sort_unique(int *a)
160 {
161         int alen;
162         int i, j;
163
164         if (a == NULL)
165                 return;
166
167         alen = int_array_len(a);
168         qsort(a, alen, sizeof(int), freq_cmp);
169
170         i = 0;
171         j = 1;
172         while (a[i] && a[j]) {
173                 if (a[i] == a[j]) {
174                         j++;
175                         continue;
176                 }
177                 a[++i] = a[j++];
178         }
179         if (a[i])
180                 i++;
181         a[i] = 0;
182 }
183
184
185 int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
186                                 struct wpa_driver_scan_params *params)
187 {
188         int ret;
189
190         wpa_supplicant_notify_scanning(wpa_s, 1);
191
192         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
193                 ret = ieee80211_sta_req_scan(wpa_s, params);
194         else
195                 ret = wpa_drv_scan(wpa_s, params);
196
197         if (ret) {
198                 wpa_supplicant_notify_scanning(wpa_s, 0);
199                 wpas_notify_scan_done(wpa_s, 0);
200         } else
201                 wpa_s->scan_runs++;
202
203         return ret;
204 }
205
206
207 static struct wpa_driver_scan_filter *
208 wpa_supplicant_build_filter_ssids(struct wpa_config *conf, size_t *num_ssids)
209 {
210         struct wpa_driver_scan_filter *ssids;
211         struct wpa_ssid *ssid;
212         size_t count;
213
214         *num_ssids = 0;
215         if (!conf->filter_ssids)
216                 return NULL;
217
218         for (count = 0, ssid = conf->ssid; ssid; ssid = ssid->next) {
219                 if (ssid->ssid && ssid->ssid_len)
220                         count++;
221         }
222         if (count == 0)
223                 return NULL;
224         ssids = os_zalloc(count * sizeof(struct wpa_driver_scan_filter));
225         if (ssids == NULL)
226                 return NULL;
227
228         for (ssid = conf->ssid; ssid; ssid = ssid->next) {
229                 if (!ssid->ssid || !ssid->ssid_len)
230                         continue;
231                 os_memcpy(ssids[*num_ssids].ssid, ssid->ssid, ssid->ssid_len);
232                 ssids[*num_ssids].ssid_len = ssid->ssid_len;
233                 (*num_ssids)++;
234         }
235
236         return ssids;
237 }
238
239
240 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
241 {
242         struct wpa_supplicant *wpa_s = eloop_ctx;
243         struct wpa_ssid *ssid;
244         int scan_req = 0, ret;
245         struct wpabuf *wps_ie = NULL;
246 #ifdef CONFIG_WPS
247         int wps = 0;
248         enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
249 #endif /* CONFIG_WPS */
250         struct wpa_driver_scan_params params;
251         size_t max_ssids;
252         enum wpa_states prev_state;
253
254         if (wpa_s->disconnected && !wpa_s->scan_req) {
255                 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
256                 return;
257         }
258
259         if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
260             !wpa_s->scan_req) {
261                 wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
262                 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
263                 return;
264         }
265
266         if (wpa_s->conf->ap_scan != 0 &&
267             (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
268                 wpa_printf(MSG_DEBUG, "Using wired authentication - "
269                            "overriding ap_scan configuration");
270                 wpa_s->conf->ap_scan = 0;
271                 wpas_notify_ap_scan_changed(wpa_s);
272         }
273
274         if (wpa_s->conf->ap_scan == 0) {
275                 wpa_supplicant_gen_assoc_event(wpa_s);
276                 return;
277         }
278
279         if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
280             wpa_s->conf->ap_scan == 2)
281                 max_ssids = 1;
282         else {
283                 max_ssids = wpa_s->max_scan_ssids;
284                 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
285                         max_ssids = WPAS_MAX_SCAN_SSIDS;
286         }
287
288 #ifdef CONFIG_WPS
289         wps = wpas_wps_in_use(wpa_s->conf, &req_type);
290 #endif /* CONFIG_WPS */
291
292         scan_req = wpa_s->scan_req;
293         wpa_s->scan_req = 0;
294
295         os_memset(&params, 0, sizeof(params));
296
297         prev_state = wpa_s->wpa_state;
298         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
299             wpa_s->wpa_state == WPA_INACTIVE)
300                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
301
302         /* Find the starting point from which to continue scanning */
303         ssid = wpa_s->conf->ssid;
304         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
305                 while (ssid) {
306                         if (ssid == wpa_s->prev_scan_ssid) {
307                                 ssid = ssid->next;
308                                 break;
309                         }
310                         ssid = ssid->next;
311                 }
312         }
313
314         if (scan_req != 2 && (wpa_s->conf->ap_scan == 2 ||
315                               wpa_s->connect_without_scan)) {
316                 wpa_s->connect_without_scan = 0;
317                 wpa_supplicant_assoc_try(wpa_s, ssid);
318                 return;
319         } else if (wpa_s->conf->ap_scan == 2) {
320                 /*
321                  * User-initiated scan request in ap_scan == 2; scan with
322                  * wildcard SSID.
323                  */
324                 ssid = NULL;
325         } else {
326                 struct wpa_ssid *start = ssid, *tssid;
327                 int freqs_set = 0;
328                 if (ssid == NULL && max_ssids > 1)
329                         ssid = wpa_s->conf->ssid;
330                 while (ssid) {
331                         if (!ssid->disabled && ssid->scan_ssid) {
332                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
333                                                   ssid->ssid, ssid->ssid_len);
334                                 params.ssids[params.num_ssids].ssid =
335                                         ssid->ssid;
336                                 params.ssids[params.num_ssids].ssid_len =
337                                         ssid->ssid_len;
338                                 params.num_ssids++;
339                                 if (params.num_ssids + 1 >= max_ssids)
340                                         break;
341                         }
342                         ssid = ssid->next;
343                         if (ssid == start)
344                                 break;
345                         if (ssid == NULL && max_ssids > 1 &&
346                             start != wpa_s->conf->ssid)
347                                 ssid = wpa_s->conf->ssid;
348                 }
349
350                 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
351                         if (tssid->disabled)
352                                 continue;
353                         if ((params.freqs || !freqs_set) && tssid->scan_freq) {
354                                 int_array_concat(&params.freqs,
355                                                  tssid->scan_freq);
356                         } else {
357                                 os_free(params.freqs);
358                                 params.freqs = NULL;
359                         }
360                         freqs_set = 1;
361                 }
362                 int_array_sort_unique(params.freqs);
363         }
364
365         if (ssid) {
366                 wpa_s->prev_scan_ssid = ssid;
367                 if (max_ssids > 1) {
368                         wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
369                                    "scan request");
370                         params.num_ssids++;
371                 }
372                 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
373         } else {
374                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
375                 params.num_ssids++;
376                 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
377         }
378
379 #ifdef CONFIG_WPS
380         if (params.freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
381                 /*
382                  * Optimize post-provisioning scan based on channel used
383                  * during provisioning.
384                  */
385                 wpa_printf(MSG_DEBUG, "WPS: Scan only frequency %u MHz that "
386                            "was used during provisioning", wpa_s->wps_freq);
387                 params.freqs = os_zalloc(2 * sizeof(int));
388                 if (params.freqs)
389                         params.freqs[0] = wpa_s->wps_freq;
390                 wpa_s->after_wps--;
391         }
392
393         if (wps) {
394                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
395                                                 wpa_s->wps->uuid, req_type);
396                 if (wps_ie) {
397                         params.extra_ies = wpabuf_head(wps_ie);
398                         params.extra_ies_len = wpabuf_len(wps_ie);
399                 }
400         }
401 #endif /* CONFIG_WPS */
402
403         params.filter_ssids = wpa_supplicant_build_filter_ssids(
404                 wpa_s->conf, &params.num_filter_ssids);
405
406         ret = wpa_supplicant_trigger_scan(wpa_s, &params);
407
408         wpabuf_free(wps_ie);
409         os_free(params.freqs);
410         os_free(params.filter_ssids);
411
412         if (ret) {
413                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
414                 if (prev_state != wpa_s->wpa_state)
415                         wpa_supplicant_set_state(wpa_s, prev_state);
416                 wpa_supplicant_req_scan(wpa_s, 1, 0);
417         }
418 }
419
420
421 /**
422  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
423  * @wpa_s: Pointer to wpa_supplicant data
424  * @sec: Number of seconds after which to scan
425  * @usec: Number of microseconds after which to scan
426  *
427  * This function is used to schedule a scan for neighboring access points after
428  * the specified time.
429  */
430 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
431 {
432         /* If there's at least one network that should be specifically scanned
433          * then don't cancel the scan and reschedule.  Some drivers do
434          * background scanning which generates frequent scan results, and that
435          * causes the specific SSID scan to get continually pushed back and
436          * never happen, which causes hidden APs to never get probe-scanned.
437          */
438         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
439             wpa_s->conf->ap_scan == 1) {
440                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
441
442                 while (ssid) {
443                         if (!ssid->disabled && ssid->scan_ssid)
444                                 break;
445                         ssid = ssid->next;
446                 }
447                 if (ssid) {
448                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
449                                 "ensure that specific SSID scans occur");
450                         return;
451                 }
452         }
453
454         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
455                 sec, usec);
456         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
457         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
458 }
459
460
461 /**
462  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
463  * @wpa_s: Pointer to wpa_supplicant data
464  *
465  * This function is used to cancel a scan request scheduled with
466  * wpa_supplicant_req_scan().
467  */
468 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
469 {
470         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
471         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
472 }
473
474
475 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
476                                     int scanning)
477 {
478         if (wpa_s->scanning != scanning) {
479                 wpa_s->scanning = scanning;
480                 wpas_notify_scanning(wpa_s);
481         }
482 }
483
484
485 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
486 {
487         int rate = 0;
488         const u8 *ie;
489         int i;
490
491         ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
492         for (i = 0; ie && i < ie[1]; i++) {
493                 if ((ie[i + 2] & 0x7f) > rate)
494                         rate = ie[i + 2] & 0x7f;
495         }
496
497         ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
498         for (i = 0; ie && i < ie[1]; i++) {
499                 if ((ie[i + 2] & 0x7f) > rate)
500                         rate = ie[i + 2] & 0x7f;
501         }
502
503         return rate;
504 }
505
506
507 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
508 {
509         const u8 *end, *pos;
510
511         pos = (const u8 *) (res + 1);
512         end = pos + res->ie_len;
513
514         while (pos + 1 < end) {
515                 if (pos + 2 + pos[1] > end)
516                         break;
517                 if (pos[0] == ie)
518                         return pos;
519                 pos += 2 + pos[1];
520         }
521
522         return NULL;
523 }
524
525
526 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
527                                   u32 vendor_type)
528 {
529         const u8 *end, *pos;
530
531         pos = (const u8 *) (res + 1);
532         end = pos + res->ie_len;
533
534         while (pos + 1 < end) {
535                 if (pos + 2 + pos[1] > end)
536                         break;
537                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
538                     vendor_type == WPA_GET_BE32(&pos[2]))
539                         return pos;
540                 pos += 2 + pos[1];
541         }
542
543         return NULL;
544 }
545
546
547 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
548                                              u32 vendor_type)
549 {
550         struct wpabuf *buf;
551         const u8 *end, *pos;
552
553         buf = wpabuf_alloc(res->ie_len);
554         if (buf == NULL)
555                 return NULL;
556
557         pos = (const u8 *) (res + 1);
558         end = pos + res->ie_len;
559
560         while (pos + 1 < end) {
561                 if (pos + 2 + pos[1] > end)
562                         break;
563                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
564                     vendor_type == WPA_GET_BE32(&pos[2]))
565                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
566                 pos += 2 + pos[1];
567         }
568
569         if (wpabuf_len(buf) == 0) {
570                 wpabuf_free(buf);
571                 buf = NULL;
572         }
573
574         return buf;
575 }
576
577
578 /* Compare function for sorting scan results. Return >0 if @b is considered
579  * better. */
580 static int wpa_scan_result_compar(const void *a, const void *b)
581 {
582         struct wpa_scan_res **_wa = (void *) a;
583         struct wpa_scan_res **_wb = (void *) b;
584         struct wpa_scan_res *wa = *_wa;
585         struct wpa_scan_res *wb = *_wb;
586         int wpa_a, wpa_b, maxrate_a, maxrate_b;
587
588         /* WPA/WPA2 support preferred */
589         wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
590                 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
591         wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
592                 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
593
594         if (wpa_b && !wpa_a)
595                 return 1;
596         if (!wpa_b && wpa_a)
597                 return -1;
598
599         /* privacy support preferred */
600         if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
601             (wb->caps & IEEE80211_CAP_PRIVACY))
602                 return 1;
603         if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
604             (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
605                 return -1;
606
607         /* best/max rate preferred if signal level close enough XXX */
608         if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
609             (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
610                 maxrate_a = wpa_scan_get_max_rate(wa);
611                 maxrate_b = wpa_scan_get_max_rate(wb);
612                 if (maxrate_a != maxrate_b)
613                         return maxrate_b - maxrate_a;
614         }
615
616         /* use freq for channel preference */
617
618         /* all things being equal, use signal level; if signal levels are
619          * identical, use quality values since some drivers may only report
620          * that value and leave the signal level zero */
621         if (wb->level == wa->level)
622                 return wb->qual - wa->qual;
623         return wb->level - wa->level;
624 }
625
626
627 /**
628  * wpa_supplicant_get_scan_results - Get scan results
629  * @wpa_s: Pointer to wpa_supplicant data
630  * @info: Information about what was scanned or %NULL if not available
631  * @new_scan: Whether a new scan was performed
632  * Returns: Scan results, %NULL on failure
633  *
634  * This function request the current scan results from the driver and updates
635  * the local BSS list wpa_s->bss. The caller is responsible for freeing the
636  * results with wpa_scan_results_free().
637  */
638 struct wpa_scan_results *
639 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
640                                 struct scan_info *info, int new_scan)
641 {
642         struct wpa_scan_results *scan_res;
643         size_t i;
644
645         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
646                 scan_res = ieee80211_sta_get_scan_results(wpa_s);
647         else
648                 scan_res = wpa_drv_get_scan_results2(wpa_s);
649         if (scan_res == NULL) {
650                 wpa_printf(MSG_DEBUG, "Failed to get scan results");
651                 return NULL;
652         }
653
654         qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
655               wpa_scan_result_compar);
656
657         wpa_bss_update_start(wpa_s);
658         for (i = 0; i < scan_res->num; i++)
659                 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
660         wpa_bss_update_end(wpa_s, info, new_scan);
661
662         return scan_res;
663 }
664
665
666 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
667 {
668         struct wpa_scan_results *scan_res;
669         scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
670         if (scan_res == NULL)
671                 return -1;
672         wpa_scan_results_free(scan_res);
673
674         return 0;
675 }
676
677
678 void wpa_scan_results_free(struct wpa_scan_results *res)
679 {
680         size_t i;
681
682         if (res == NULL)
683                 return;
684
685         for (i = 0; i < res->num; i++)
686                 os_free(res->res[i]);
687         os_free(res->res);
688         os_free(res);
689 }