2 * WPA Supplicant - Scanning
3 * Copyright (c) 2003-2010, Jouni Malinen <j@w1.fi>
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.
9 * Alternatively, this software may be distributed under the terms of BSD
12 * See README and COPYING for more details.
15 #include "utils/includes.h"
17 #include "utils/common.h"
18 #include "utils/eloop.h"
19 #include "common/ieee802_11_defs.h"
21 #include "wpa_supplicant_i.h"
24 #include "wps_supplicant.h"
25 #include "p2p_supplicant.h"
32 static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
34 struct wpa_ssid *ssid;
35 union wpa_event_data data;
37 ssid = wpa_supplicant_get_ssid(wpa_s);
41 if (wpa_s->current_ssid == NULL) {
42 wpa_s->current_ssid = ssid;
43 if (wpa_s->current_ssid != NULL)
44 wpas_notify_network_changed(wpa_s);
46 wpa_supplicant_initiate_eapol(wpa_s);
47 wpa_printf(MSG_DEBUG, "Already associated with a configured network - "
48 "generating associated event");
49 os_memset(&data, 0, sizeof(data));
50 wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);
55 static int wpas_wps_in_use(struct wpa_config *conf,
56 enum wps_request_type *req_type)
58 struct wpa_ssid *ssid;
61 for (ssid = conf->ssid; ssid; ssid = ssid->next) {
62 if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
66 *req_type = wpas_wps_get_req_type(ssid);
67 if (!ssid->eap.phase1)
70 if (os_strstr(ssid->eap.phase1, "pbc=1"))
76 #endif /* CONFIG_WPS */
79 int wpa_supplicant_enabled_networks(struct wpa_config *conf)
81 struct wpa_ssid *ssid = conf->ssid;
91 static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
92 struct wpa_ssid *ssid)
100 /* ap_scan=2 mode - try to associate with each SSID. */
102 wpa_printf(MSG_DEBUG, "wpa_supplicant_scan: Reached "
103 "end of scan list - go back to beginning");
104 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
105 wpa_supplicant_req_scan(wpa_s, 0, 0);
109 /* Continue from the next SSID on the next attempt. */
110 wpa_s->prev_scan_ssid = ssid;
112 /* Start from the beginning of the SSID list. */
113 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
115 wpa_supplicant_associate(wpa_s, NULL, ssid);
119 static int int_array_len(const int *a)
122 for (i = 0; a && a[i]; i++)
128 static void int_array_concat(int **res, const int *a)
133 reslen = int_array_len(*res);
134 alen = int_array_len(a);
136 n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
142 for (i = 0; i <= alen; i++)
143 n[reslen + i] = a[i];
148 static int freq_cmp(const void *a, const void *b)
161 static void int_array_sort_unique(int *a)
169 alen = int_array_len(a);
170 qsort(a, alen, sizeof(int), freq_cmp);
174 while (a[i] && a[j]) {
187 int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
188 struct wpa_driver_scan_params *params)
192 wpa_supplicant_notify_scanning(wpa_s, 1);
194 if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
195 ret = ieee80211_sta_req_scan(wpa_s, params);
197 ret = wpa_drv_scan(wpa_s, params);
200 wpa_supplicant_notify_scanning(wpa_s, 0);
201 wpas_notify_scan_done(wpa_s, 0);
209 static struct wpa_driver_scan_filter *
210 wpa_supplicant_build_filter_ssids(struct wpa_config *conf, size_t *num_ssids)
212 struct wpa_driver_scan_filter *ssids;
213 struct wpa_ssid *ssid;
217 if (!conf->filter_ssids)
220 for (count = 0, ssid = conf->ssid; ssid; ssid = ssid->next) {
221 if (ssid->ssid && ssid->ssid_len)
226 ssids = os_zalloc(count * sizeof(struct wpa_driver_scan_filter));
230 for (ssid = conf->ssid; ssid; ssid = ssid->next) {
231 if (!ssid->ssid || !ssid->ssid_len)
233 os_memcpy(ssids[*num_ssids].ssid, ssid->ssid, ssid->ssid_len);
234 ssids[*num_ssids].ssid_len = ssid->ssid_len;
242 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
244 struct wpa_supplicant *wpa_s = eloop_ctx;
245 struct wpa_ssid *ssid;
246 int scan_req = 0, ret;
247 struct wpabuf *wps_ie = NULL;
250 enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
251 #endif /* CONFIG_WPS */
252 struct wpa_driver_scan_params params;
254 enum wpa_states prev_state;
256 if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
257 wpa_printf(MSG_DEBUG, "Skip scan - interface disabled");
261 if (wpa_s->disconnected && !wpa_s->scan_req) {
262 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
266 if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
268 wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
269 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
273 if (wpa_s->conf->ap_scan != 0 &&
274 (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
275 wpa_printf(MSG_DEBUG, "Using wired authentication - "
276 "overriding ap_scan configuration");
277 wpa_s->conf->ap_scan = 0;
278 wpas_notify_ap_scan_changed(wpa_s);
281 if (wpa_s->conf->ap_scan == 0) {
282 wpa_supplicant_gen_assoc_event(wpa_s);
286 if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
287 wpa_s->conf->ap_scan == 2)
290 max_ssids = wpa_s->max_scan_ssids;
291 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
292 max_ssids = WPAS_MAX_SCAN_SSIDS;
296 wps = wpas_wps_in_use(wpa_s->conf, &req_type);
297 #endif /* CONFIG_WPS */
299 scan_req = wpa_s->scan_req;
302 os_memset(¶ms, 0, sizeof(params));
304 prev_state = wpa_s->wpa_state;
305 if (wpa_s->wpa_state == WPA_DISCONNECTED ||
306 wpa_s->wpa_state == WPA_INACTIVE)
307 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
309 /* Find the starting point from which to continue scanning */
310 ssid = wpa_s->conf->ssid;
311 if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
313 if (ssid == wpa_s->prev_scan_ssid) {
321 if (scan_req != 2 && (wpa_s->conf->ap_scan == 2 ||
322 wpa_s->connect_without_scan)) {
323 wpa_s->connect_without_scan = 0;
324 wpa_supplicant_assoc_try(wpa_s, ssid);
326 } else if (wpa_s->conf->ap_scan == 2) {
328 * User-initiated scan request in ap_scan == 2; scan with
333 struct wpa_ssid *start = ssid, *tssid;
335 if (ssid == NULL && max_ssids > 1)
336 ssid = wpa_s->conf->ssid;
338 if (!ssid->disabled && ssid->scan_ssid) {
339 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
340 ssid->ssid, ssid->ssid_len);
341 params.ssids[params.num_ssids].ssid =
343 params.ssids[params.num_ssids].ssid_len =
346 if (params.num_ssids + 1 >= max_ssids)
352 if (ssid == NULL && max_ssids > 1 &&
353 start != wpa_s->conf->ssid)
354 ssid = wpa_s->conf->ssid;
357 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
360 if ((params.freqs || !freqs_set) && tssid->scan_freq) {
361 int_array_concat(¶ms.freqs,
364 os_free(params.freqs);
369 int_array_sort_unique(params.freqs);
373 wpa_s->prev_scan_ssid = ssid;
375 wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
379 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
381 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
383 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
387 wpa_s->wps->dev.p2p = 1;
390 req_type = WPS_REQ_ENROLLEE_INFO;
393 if (params.freqs == NULL && wpa_s->p2p_in_provisioning &&
395 /* Optimize provisioning state scan based on GO information */
396 if (wpa_s->p2p_in_provisioning < 5 &&
397 wpa_s->go_params->freq > 0) {
398 wpa_printf(MSG_DEBUG, "P2P: Scan only GO preferred "
400 wpa_s->go_params->freq);
401 params.freqs = os_zalloc(2 * sizeof(int));
403 params.freqs[0] = wpa_s->go_params->freq;
404 } else if (wpa_s->go_params->freq_list[0]) {
405 wpa_printf(MSG_DEBUG, "P2P: Scan only common "
407 int_array_concat(¶ms.freqs,
408 wpa_s->go_params->freq_list);
410 int_array_sort_unique(params.freqs);
412 wpa_s->p2p_in_provisioning++;
414 #endif /* CONFIG_P2P */
417 if (params.freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
419 * Optimize post-provisioning scan based on channel used
420 * during provisioning.
422 wpa_printf(MSG_DEBUG, "WPS: Scan only frequency %u MHz that "
423 "was used during provisioning", wpa_s->wps_freq);
424 params.freqs = os_zalloc(2 * sizeof(int));
426 params.freqs[0] = wpa_s->wps_freq;
431 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
432 wpa_s->wps->uuid, req_type);
434 params.extra_ies = wpabuf_head(wps_ie);
435 params.extra_ies_len = wpabuf_len(wps_ie);
438 #endif /* CONFIG_WPS */
442 if (wpabuf_resize(&wps_ie, 100) == 0) {
443 wpas_p2p_scan_ie(wpa_s, wps_ie);
444 params.extra_ies = wpabuf_head(wps_ie);
445 params.extra_ies_len = wpabuf_len(wps_ie);
448 #endif /* CONFIG_P2P */
450 params.filter_ssids = wpa_supplicant_build_filter_ssids(
451 wpa_s->conf, ¶ms.num_filter_ssids);
453 ret = wpa_supplicant_trigger_scan(wpa_s, ¶ms);
456 os_free(params.freqs);
457 os_free(params.filter_ssids);
460 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
461 if (prev_state != wpa_s->wpa_state)
462 wpa_supplicant_set_state(wpa_s, prev_state);
463 wpa_supplicant_req_scan(wpa_s, 1, 0);
469 * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
470 * @wpa_s: Pointer to wpa_supplicant data
471 * @sec: Number of seconds after which to scan
472 * @usec: Number of microseconds after which to scan
474 * This function is used to schedule a scan for neighboring access points after
475 * the specified time.
477 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
479 /* If there's at least one network that should be specifically scanned
480 * then don't cancel the scan and reschedule. Some drivers do
481 * background scanning which generates frequent scan results, and that
482 * causes the specific SSID scan to get continually pushed back and
483 * never happen, which causes hidden APs to never get probe-scanned.
485 if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
486 wpa_s->conf->ap_scan == 1) {
487 struct wpa_ssid *ssid = wpa_s->conf->ssid;
490 if (!ssid->disabled && ssid->scan_ssid)
495 wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
496 "ensure that specific SSID scans occur");
501 wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
503 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
504 eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
509 * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
510 * @wpa_s: Pointer to wpa_supplicant data
512 * This function is used to cancel a scan request scheduled with
513 * wpa_supplicant_req_scan().
515 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
517 wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
518 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
522 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
525 if (wpa_s->scanning != scanning) {
526 wpa_s->scanning = scanning;
527 wpas_notify_scanning(wpa_s);
532 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
538 ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
539 for (i = 0; ie && i < ie[1]; i++) {
540 if ((ie[i + 2] & 0x7f) > rate)
541 rate = ie[i + 2] & 0x7f;
544 ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
545 for (i = 0; ie && i < ie[1]; i++) {
546 if ((ie[i + 2] & 0x7f) > rate)
547 rate = ie[i + 2] & 0x7f;
554 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
558 pos = (const u8 *) (res + 1);
559 end = pos + res->ie_len;
561 while (pos + 1 < end) {
562 if (pos + 2 + pos[1] > end)
573 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
578 pos = (const u8 *) (res + 1);
579 end = pos + res->ie_len;
581 while (pos + 1 < end) {
582 if (pos + 2 + pos[1] > end)
584 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
585 vendor_type == WPA_GET_BE32(&pos[2]))
594 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
600 buf = wpabuf_alloc(res->ie_len);
604 pos = (const u8 *) (res + 1);
605 end = pos + res->ie_len;
607 while (pos + 1 < end) {
608 if (pos + 2 + pos[1] > end)
610 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
611 vendor_type == WPA_GET_BE32(&pos[2]))
612 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
616 if (wpabuf_len(buf) == 0) {
625 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
626 const struct wpa_scan_res *res, u32 vendor_type)
631 if (res->beacon_ie_len == 0)
633 buf = wpabuf_alloc(res->beacon_ie_len);
637 pos = (const u8 *) (res + 1);
639 end = pos + res->beacon_ie_len;
641 while (pos + 1 < end) {
642 if (pos + 2 + pos[1] > end)
644 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
645 vendor_type == WPA_GET_BE32(&pos[2]))
646 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
650 if (wpabuf_len(buf) == 0) {
659 /* Compare function for sorting scan results. Return >0 if @b is considered
661 static int wpa_scan_result_compar(const void *a, const void *b)
663 struct wpa_scan_res **_wa = (void *) a;
664 struct wpa_scan_res **_wb = (void *) b;
665 struct wpa_scan_res *wa = *_wa;
666 struct wpa_scan_res *wb = *_wb;
667 int wpa_a, wpa_b, maxrate_a, maxrate_b;
669 /* WPA/WPA2 support preferred */
670 wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
671 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
672 wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
673 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
680 /* privacy support preferred */
681 if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
682 (wb->caps & IEEE80211_CAP_PRIVACY))
684 if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
685 (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
688 /* best/max rate preferred if signal level close enough XXX */
689 if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
690 (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
691 maxrate_a = wpa_scan_get_max_rate(wa);
692 maxrate_b = wpa_scan_get_max_rate(wb);
693 if (maxrate_a != maxrate_b)
694 return maxrate_b - maxrate_a;
697 /* use freq for channel preference */
699 /* all things being equal, use signal level; if signal levels are
700 * identical, use quality values since some drivers may only report
701 * that value and leave the signal level zero */
702 if (wb->level == wa->level)
703 return wb->qual - wa->qual;
704 return wb->level - wa->level;
709 /* Compare function for sorting scan results when searching a WPS AP for
710 * provisioning. Return >0 if @b is considered better. */
711 static int wpa_scan_result_wps_compar(const void *a, const void *b)
713 struct wpa_scan_res **_wa = (void *) a;
714 struct wpa_scan_res **_wb = (void *) b;
715 struct wpa_scan_res *wa = *_wa;
716 struct wpa_scan_res *wb = *_wb;
717 int uses_wps_a, uses_wps_b;
718 struct wpabuf *wps_a, *wps_b;
721 /* Optimization - check WPS IE existence before allocated memory and
722 * doing full reassembly. */
723 uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
724 uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
725 if (uses_wps_a && !uses_wps_b)
727 if (!uses_wps_a && uses_wps_b)
730 if (uses_wps_a && uses_wps_b) {
731 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
732 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
733 res = wps_ap_priority_compar(wps_a, wps_b);
741 * Do not use current AP security policy as a sorting criteria during
742 * WPS provisioning step since the AP may get reconfigured at the
743 * completion of provisioning.
746 /* all things being equal, use signal level; if signal levels are
747 * identical, use quality values since some drivers may only report
748 * that value and leave the signal level zero */
749 if (wb->level == wa->level)
750 return wb->qual - wa->qual;
751 return wb->level - wa->level;
753 #endif /* CONFIG_WPS */
757 * wpa_supplicant_get_scan_results - Get scan results
758 * @wpa_s: Pointer to wpa_supplicant data
759 * @info: Information about what was scanned or %NULL if not available
760 * @new_scan: Whether a new scan was performed
761 * Returns: Scan results, %NULL on failure
763 * This function request the current scan results from the driver and updates
764 * the local BSS list wpa_s->bss. The caller is responsible for freeing the
765 * results with wpa_scan_results_free().
767 struct wpa_scan_results *
768 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
769 struct scan_info *info, int new_scan)
771 struct wpa_scan_results *scan_res;
773 int (*compar)(const void *, const void *) = wpa_scan_result_compar;
775 if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
776 scan_res = ieee80211_sta_get_scan_results(wpa_s);
778 scan_res = wpa_drv_get_scan_results2(wpa_s);
779 if (scan_res == NULL) {
780 wpa_printf(MSG_DEBUG, "Failed to get scan results");
785 if (wpas_wps_in_progress(wpa_s)) {
786 wpa_printf(MSG_DEBUG, "WPS: Order scan results with WPS "
787 "provisioning rules");
788 compar = wpa_scan_result_wps_compar;
790 #endif /* CONFIG_WPS */
792 qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
795 wpa_bss_update_start(wpa_s);
796 for (i = 0; i < scan_res->num; i++)
797 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
798 wpa_bss_update_end(wpa_s, info, new_scan);
804 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
806 struct wpa_scan_results *scan_res;
807 scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
808 if (scan_res == NULL)
810 wpa_scan_results_free(scan_res);
816 void wpa_scan_results_free(struct wpa_scan_results *res)
823 for (i = 0; i < res->num; i++)
824 os_free(res->res[i]);