Add optional scan result filter based on SSID
[mech_eap.git] / 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         int wps = 0;
247 #ifdef CONFIG_WPS
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         if (wpa_s->scan_res_tried == 0 && wpa_s->conf->ap_scan == 1 &&
293             !(wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) &&
294             wps != 2 && !wpa_s->conf->filter_ssids) {
295                 wpa_s->scan_res_tried++;
296                 wpa_printf(MSG_DEBUG, "Trying to get current scan results "
297                            "first without requesting a new scan to speed up "
298                            "initial association");
299                 wpa_supplicant_event(wpa_s, EVENT_SCAN_RESULTS, NULL);
300                 return;
301         }
302
303         scan_req = wpa_s->scan_req;
304         wpa_s->scan_req = 0;
305
306         os_memset(&params, 0, sizeof(params));
307
308         prev_state = wpa_s->wpa_state;
309         if (wpa_s->wpa_state == WPA_DISCONNECTED ||
310             wpa_s->wpa_state == WPA_INACTIVE)
311                 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
312
313         /* Find the starting point from which to continue scanning */
314         ssid = wpa_s->conf->ssid;
315         if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
316                 while (ssid) {
317                         if (ssid == wpa_s->prev_scan_ssid) {
318                                 ssid = ssid->next;
319                                 break;
320                         }
321                         ssid = ssid->next;
322                 }
323         }
324
325         if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
326                 wpa_supplicant_assoc_try(wpa_s, ssid);
327                 return;
328         } else if (wpa_s->conf->ap_scan == 2) {
329                 /*
330                  * User-initiated scan request in ap_scan == 2; scan with
331                  * wildcard SSID.
332                  */
333                 ssid = NULL;
334         } else {
335                 struct wpa_ssid *start = ssid, *tssid;
336                 int freqs_set = 0;
337                 if (ssid == NULL && max_ssids > 1)
338                         ssid = wpa_s->conf->ssid;
339                 while (ssid) {
340                         if (!ssid->disabled && ssid->scan_ssid) {
341                                 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
342                                                   ssid->ssid, ssid->ssid_len);
343                                 params.ssids[params.num_ssids].ssid =
344                                         ssid->ssid;
345                                 params.ssids[params.num_ssids].ssid_len =
346                                         ssid->ssid_len;
347                                 params.num_ssids++;
348                                 if (params.num_ssids + 1 >= max_ssids)
349                                         break;
350                         }
351                         ssid = ssid->next;
352                         if (ssid == start)
353                                 break;
354                         if (ssid == NULL && max_ssids > 1 &&
355                             start != wpa_s->conf->ssid)
356                                 ssid = wpa_s->conf->ssid;
357                 }
358
359                 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
360                         if (tssid->disabled)
361                                 continue;
362                         if ((params.freqs || !freqs_set) && tssid->scan_freq) {
363                                 int_array_concat(&params.freqs,
364                                                  tssid->scan_freq);
365                         } else {
366                                 os_free(params.freqs);
367                                 params.freqs = NULL;
368                         }
369                         freqs_set = 1;
370                 }
371                 int_array_sort_unique(params.freqs);
372         }
373
374         if (ssid) {
375                 wpa_s->prev_scan_ssid = ssid;
376                 if (max_ssids > 1) {
377                         wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
378                                    "scan request");
379                         params.num_ssids++;
380                 }
381                 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
382         } else {
383                 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
384                 params.num_ssids++;
385                 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
386         }
387
388 #ifdef CONFIG_WPS
389         if (wps) {
390                 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
391                                                 wpa_s->wps->uuid, req_type);
392                 if (wps_ie) {
393                         params.extra_ies = wpabuf_head(wps_ie);
394                         params.extra_ies_len = wpabuf_len(wps_ie);
395                 }
396         }
397 #endif /* CONFIG_WPS */
398
399         params.filter_ssids = wpa_supplicant_build_filter_ssids(
400                 wpa_s->conf, &params.num_filter_ssids);
401
402         ret = wpa_supplicant_trigger_scan(wpa_s, &params);
403
404         wpabuf_free(wps_ie);
405         os_free(params.freqs);
406         os_free(params.filter_ssids);
407
408         if (ret) {
409                 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
410                 if (prev_state != wpa_s->wpa_state)
411                         wpa_supplicant_set_state(wpa_s, prev_state);
412                 wpa_supplicant_req_scan(wpa_s, 10, 0);
413         } else
414                 wpa_s->scan_runs++;
415 }
416
417
418 /**
419  * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
420  * @wpa_s: Pointer to wpa_supplicant data
421  * @sec: Number of seconds after which to scan
422  * @usec: Number of microseconds after which to scan
423  *
424  * This function is used to schedule a scan for neighboring access points after
425  * the specified time.
426  */
427 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
428 {
429         /* If there's at least one network that should be specifically scanned
430          * then don't cancel the scan and reschedule.  Some drivers do
431          * background scanning which generates frequent scan results, and that
432          * causes the specific SSID scan to get continually pushed back and
433          * never happen, which causes hidden APs to never get probe-scanned.
434          */
435         if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
436             wpa_s->conf->ap_scan == 1) {
437                 struct wpa_ssid *ssid = wpa_s->conf->ssid;
438
439                 while (ssid) {
440                         if (!ssid->disabled && ssid->scan_ssid)
441                                 break;
442                         ssid = ssid->next;
443                 }
444                 if (ssid) {
445                         wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
446                                 "ensure that specific SSID scans occur");
447                         return;
448                 }
449         }
450
451         wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
452                 sec, usec);
453         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
454         eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
455 }
456
457
458 /**
459  * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
460  * @wpa_s: Pointer to wpa_supplicant data
461  *
462  * This function is used to cancel a scan request scheduled with
463  * wpa_supplicant_req_scan().
464  */
465 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
466 {
467         wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
468         eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
469 }
470
471
472 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
473                                     int scanning)
474 {
475         if (wpa_s->scanning != scanning) {
476                 wpa_s->scanning = scanning;
477                 wpas_notify_scanning(wpa_s);
478         }
479 }
480
481
482 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
483 {
484         int rate = 0;
485         const u8 *ie;
486         int i;
487
488         ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
489         for (i = 0; ie && i < ie[1]; i++) {
490                 if ((ie[i + 2] & 0x7f) > rate)
491                         rate = ie[i + 2] & 0x7f;
492         }
493
494         ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
495         for (i = 0; ie && i < ie[1]; i++) {
496                 if ((ie[i + 2] & 0x7f) > rate)
497                         rate = ie[i + 2] & 0x7f;
498         }
499
500         return rate;
501 }
502
503
504 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
505 {
506         const u8 *end, *pos;
507
508         pos = (const u8 *) (res + 1);
509         end = pos + res->ie_len;
510
511         while (pos + 1 < end) {
512                 if (pos + 2 + pos[1] > end)
513                         break;
514                 if (pos[0] == ie)
515                         return pos;
516                 pos += 2 + pos[1];
517         }
518
519         return NULL;
520 }
521
522
523 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
524                                   u32 vendor_type)
525 {
526         const u8 *end, *pos;
527
528         pos = (const u8 *) (res + 1);
529         end = pos + res->ie_len;
530
531         while (pos + 1 < end) {
532                 if (pos + 2 + pos[1] > end)
533                         break;
534                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
535                     vendor_type == WPA_GET_BE32(&pos[2]))
536                         return pos;
537                 pos += 2 + pos[1];
538         }
539
540         return NULL;
541 }
542
543
544 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
545                                              u32 vendor_type)
546 {
547         struct wpabuf *buf;
548         const u8 *end, *pos;
549
550         buf = wpabuf_alloc(res->ie_len);
551         if (buf == NULL)
552                 return NULL;
553
554         pos = (const u8 *) (res + 1);
555         end = pos + res->ie_len;
556
557         while (pos + 1 < end) {
558                 if (pos + 2 + pos[1] > end)
559                         break;
560                 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
561                     vendor_type == WPA_GET_BE32(&pos[2]))
562                         wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
563                 pos += 2 + pos[1];
564         }
565
566         if (wpabuf_len(buf) == 0) {
567                 wpabuf_free(buf);
568                 buf = NULL;
569         }
570
571         return buf;
572 }
573
574
575 /* Compare function for sorting scan results. Return >0 if @b is considered
576  * better. */
577 static int wpa_scan_result_compar(const void *a, const void *b)
578 {
579         struct wpa_scan_res **_wa = (void *) a;
580         struct wpa_scan_res **_wb = (void *) b;
581         struct wpa_scan_res *wa = *_wa;
582         struct wpa_scan_res *wb = *_wb;
583         int wpa_a, wpa_b, maxrate_a, maxrate_b;
584
585         /* WPA/WPA2 support preferred */
586         wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
587                 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
588         wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
589                 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
590
591         if (wpa_b && !wpa_a)
592                 return 1;
593         if (!wpa_b && wpa_a)
594                 return -1;
595
596         /* privacy support preferred */
597         if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
598             (wb->caps & IEEE80211_CAP_PRIVACY))
599                 return 1;
600         if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
601             (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
602                 return -1;
603
604         /* best/max rate preferred if signal level close enough XXX */
605         if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
606             (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
607                 maxrate_a = wpa_scan_get_max_rate(wa);
608                 maxrate_b = wpa_scan_get_max_rate(wb);
609                 if (maxrate_a != maxrate_b)
610                         return maxrate_b - maxrate_a;
611         }
612
613         /* use freq for channel preference */
614
615         /* all things being equal, use signal level; if signal levels are
616          * identical, use quality values since some drivers may only report
617          * that value and leave the signal level zero */
618         if (wb->level == wa->level)
619                 return wb->qual - wa->qual;
620         return wb->level - wa->level;
621 }
622
623
624 /**
625  * wpa_supplicant_get_scan_results - Get scan results
626  * @wpa_s: Pointer to wpa_supplicant data
627  * @info: Information about what was scanned or %NULL if not available
628  * @new_scan: Whether a new scan was performed
629  * Returns: Scan results, %NULL on failure
630  *
631  * This function request the current scan results from the driver and updates
632  * the local BSS list wpa_s->bss. The caller is responsible for freeing the
633  * results with wpa_scan_results_free().
634  */
635 struct wpa_scan_results *
636 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
637                                 struct scan_info *info, int new_scan)
638 {
639         struct wpa_scan_results *scan_res;
640         size_t i;
641
642         if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
643                 scan_res = ieee80211_sta_get_scan_results(wpa_s);
644         else
645                 scan_res = wpa_drv_get_scan_results2(wpa_s);
646         if (scan_res == NULL) {
647                 wpa_printf(MSG_DEBUG, "Failed to get scan results");
648                 return NULL;
649         }
650
651         qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
652               wpa_scan_result_compar);
653
654         wpa_bss_update_start(wpa_s);
655         for (i = 0; i < scan_res->num; i++)
656                 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
657         wpa_bss_update_end(wpa_s, info, new_scan);
658
659         return scan_res;
660 }
661
662
663 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
664 {
665         struct wpa_scan_results *scan_res;
666         scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
667         if (scan_res == NULL)
668                 return -1;
669         wpa_scan_results_free(scan_res);
670
671         return 0;
672 }
673
674
675 void wpa_scan_results_free(struct wpa_scan_results *res)
676 {
677         size_t i;
678
679         if (res == NULL)
680                 return;
681
682         for (i = 0; i < res->num; i++)
683                 os_free(res->res[i]);
684         os_free(res->res);
685         os_free(res);
686 }