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_dbg(wpa_s, MSG_DEBUG, "Already associated with a configured "
48 "network - 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;
92 static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
93 struct wpa_ssid *ssid)
101 /* ap_scan=2 mode - try to associate with each SSID. */
103 wpa_dbg(wpa_s, MSG_DEBUG, "wpa_supplicant_assoc_try: Reached "
104 "end of scan list - go back to beginning");
105 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
106 wpa_supplicant_req_scan(wpa_s, 0, 0);
110 /* Continue from the next SSID on the next attempt. */
111 wpa_s->prev_scan_ssid = ssid;
113 /* Start from the beginning of the SSID list. */
114 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
116 wpa_supplicant_associate(wpa_s, NULL, ssid);
120 static int int_array_len(const int *a)
123 for (i = 0; a && a[i]; i++)
129 static void int_array_concat(int **res, const int *a)
134 reslen = int_array_len(*res);
135 alen = int_array_len(a);
137 n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
143 for (i = 0; i <= alen; i++)
144 n[reslen + i] = a[i];
149 static int freq_cmp(const void *a, const void *b)
162 static void int_array_sort_unique(int *a)
170 alen = int_array_len(a);
171 qsort(a, alen, sizeof(int), freq_cmp);
175 while (a[i] && a[j]) {
188 int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
189 struct wpa_driver_scan_params *params)
193 wpa_supplicant_notify_scanning(wpa_s, 1);
195 if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
196 ret = ieee80211_sta_req_scan(wpa_s, params);
198 ret = wpa_drv_scan(wpa_s, params);
201 wpa_supplicant_notify_scanning(wpa_s, 0);
202 wpas_notify_scan_done(wpa_s, 0);
210 static struct wpa_driver_scan_filter *
211 wpa_supplicant_build_filter_ssids(struct wpa_config *conf, size_t *num_ssids)
213 struct wpa_driver_scan_filter *ssids;
214 struct wpa_ssid *ssid;
218 if (!conf->filter_ssids)
221 for (count = 0, ssid = conf->ssid; ssid; ssid = ssid->next) {
222 if (ssid->ssid && ssid->ssid_len)
227 ssids = os_zalloc(count * sizeof(struct wpa_driver_scan_filter));
231 for (ssid = conf->ssid; ssid; ssid = ssid->next) {
232 if (!ssid->ssid || !ssid->ssid_len)
234 os_memcpy(ssids[*num_ssids].ssid, ssid->ssid, ssid->ssid_len);
235 ssids[*num_ssids].ssid_len = ssid->ssid_len;
243 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
245 struct wpa_supplicant *wpa_s = eloop_ctx;
246 struct wpa_ssid *ssid;
247 int scan_req = 0, ret;
248 struct wpabuf *wps_ie = NULL;
251 enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
252 #endif /* CONFIG_WPS */
253 struct wpa_driver_scan_params params;
255 enum wpa_states prev_state;
257 if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
258 wpa_dbg(wpa_s, MSG_DEBUG, "Skip scan - interface disabled");
262 if (wpa_s->disconnected && !wpa_s->scan_req) {
263 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
267 if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
269 wpa_dbg(wpa_s, MSG_DEBUG, "No enabled networks - do not scan");
270 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
274 if (wpa_s->conf->ap_scan != 0 &&
275 (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
276 wpa_dbg(wpa_s, MSG_DEBUG, "Using wired authentication - "
277 "overriding ap_scan configuration");
278 wpa_s->conf->ap_scan = 0;
279 wpas_notify_ap_scan_changed(wpa_s);
282 if (wpa_s->conf->ap_scan == 0) {
283 wpa_supplicant_gen_assoc_event(wpa_s);
287 if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
288 wpa_s->conf->ap_scan == 2)
291 max_ssids = wpa_s->max_scan_ssids;
292 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
293 max_ssids = WPAS_MAX_SCAN_SSIDS;
297 wps = wpas_wps_in_use(wpa_s->conf, &req_type);
298 #endif /* CONFIG_WPS */
300 scan_req = wpa_s->scan_req;
303 os_memset(¶ms, 0, sizeof(params));
305 prev_state = wpa_s->wpa_state;
306 if (wpa_s->wpa_state == WPA_DISCONNECTED ||
307 wpa_s->wpa_state == WPA_INACTIVE)
308 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
310 if (scan_req != 2 && wpa_s->connect_without_scan) {
311 for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
312 if (ssid == wpa_s->connect_without_scan)
315 wpa_s->connect_without_scan = NULL;
317 wpa_printf(MSG_DEBUG, "Start a pre-selected network "
318 "without scan step");
319 wpa_supplicant_associate(wpa_s, NULL, ssid);
324 /* Find the starting point from which to continue scanning */
325 ssid = wpa_s->conf->ssid;
326 if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
328 if (ssid == wpa_s->prev_scan_ssid) {
336 if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
337 wpa_s->connect_without_scan = NULL;
338 wpa_supplicant_assoc_try(wpa_s, ssid);
341 } else if (wpa_s->conf->ap_scan == 2) {
343 * User-initiated scan request in ap_scan == 2; scan with
349 struct wpa_ssid *start = ssid, *tssid;
351 if (ssid == NULL && max_ssids > 1)
352 ssid = wpa_s->conf->ssid;
354 if (!ssid->disabled && ssid->scan_ssid) {
355 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
356 ssid->ssid, ssid->ssid_len);
357 params.ssids[params.num_ssids].ssid =
359 params.ssids[params.num_ssids].ssid_len =
362 if (params.num_ssids + 1 >= max_ssids)
368 if (ssid == NULL && max_ssids > 1 &&
369 start != wpa_s->conf->ssid)
370 ssid = wpa_s->conf->ssid;
373 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
376 if ((params.freqs || !freqs_set) && tssid->scan_freq) {
377 int_array_concat(¶ms.freqs,
380 os_free(params.freqs);
385 int_array_sort_unique(params.freqs);
389 wpa_s->prev_scan_ssid = ssid;
391 wpa_dbg(wpa_s, MSG_DEBUG, "Include wildcard SSID in "
395 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for specific "
398 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
400 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for wildcard "
405 wpa_s->wps->dev.p2p = 1;
408 req_type = WPS_REQ_ENROLLEE_INFO;
411 if (params.freqs == NULL && wpa_s->p2p_in_provisioning &&
413 /* Optimize provisioning state scan based on GO information */
414 if (wpa_s->p2p_in_provisioning < 5 &&
415 wpa_s->go_params->freq > 0) {
416 wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only GO "
417 "preferred frequency %d MHz",
418 wpa_s->go_params->freq);
419 params.freqs = os_zalloc(2 * sizeof(int));
421 params.freqs[0] = wpa_s->go_params->freq;
422 } else if (wpa_s->p2p_in_provisioning < 8 &&
423 wpa_s->go_params->freq_list[0]) {
424 wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only common "
426 int_array_concat(¶ms.freqs,
427 wpa_s->go_params->freq_list);
429 int_array_sort_unique(params.freqs);
431 wpa_s->p2p_in_provisioning++;
433 #endif /* CONFIG_P2P */
436 if (params.freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
438 * Optimize post-provisioning scan based on channel used
439 * during provisioning.
441 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Scan only frequency %u MHz "
442 "that was used during provisioning", wpa_s->wps_freq);
443 params.freqs = os_zalloc(2 * sizeof(int));
445 params.freqs[0] = wpa_s->wps_freq;
450 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
451 wpa_s->wps->uuid, req_type,
454 params.extra_ies = wpabuf_head(wps_ie);
455 params.extra_ies_len = wpabuf_len(wps_ie);
458 #endif /* CONFIG_WPS */
462 if (wpabuf_resize(&wps_ie, 100) == 0) {
463 wpas_p2p_scan_ie(wpa_s, wps_ie);
464 params.extra_ies = wpabuf_head(wps_ie);
465 params.extra_ies_len = wpabuf_len(wps_ie);
468 #endif /* CONFIG_P2P */
470 if (params.freqs == NULL && wpa_s->next_scan_freqs) {
471 wpa_dbg(wpa_s, MSG_DEBUG, "Optimize scan based on previously "
472 "generated frequency list");
473 params.freqs = wpa_s->next_scan_freqs;
475 os_free(wpa_s->next_scan_freqs);
476 wpa_s->next_scan_freqs = NULL;
478 params.filter_ssids = wpa_supplicant_build_filter_ssids(
479 wpa_s->conf, ¶ms.num_filter_ssids);
481 ret = wpa_supplicant_trigger_scan(wpa_s, ¶ms);
484 os_free(params.freqs);
485 os_free(params.filter_ssids);
488 wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate AP scan");
489 if (prev_state != wpa_s->wpa_state)
490 wpa_supplicant_set_state(wpa_s, prev_state);
491 wpa_supplicant_req_scan(wpa_s, 1, 0);
497 * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
498 * @wpa_s: Pointer to wpa_supplicant data
499 * @sec: Number of seconds after which to scan
500 * @usec: Number of microseconds after which to scan
502 * This function is used to schedule a scan for neighboring access points after
503 * the specified time.
505 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
507 /* If there's at least one network that should be specifically scanned
508 * then don't cancel the scan and reschedule. Some drivers do
509 * background scanning which generates frequent scan results, and that
510 * causes the specific SSID scan to get continually pushed back and
511 * never happen, which causes hidden APs to never get probe-scanned.
513 if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
514 wpa_s->conf->ap_scan == 1) {
515 struct wpa_ssid *ssid = wpa_s->conf->ssid;
518 if (!ssid->disabled && ssid->scan_ssid)
523 wpa_dbg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
524 "ensure that specific SSID scans occur");
529 wpa_dbg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
531 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
532 eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
537 * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
538 * @wpa_s: Pointer to wpa_supplicant data
540 * This function is used to cancel a scan request scheduled with
541 * wpa_supplicant_req_scan().
543 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
545 wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling scan request");
546 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
547 wpa_supplicant_notify_scanning(wpa_s, 0);
551 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
554 if (wpa_s->scanning != scanning) {
555 wpa_s->scanning = scanning;
556 wpas_notify_scanning(wpa_s);
561 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
567 ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
568 for (i = 0; ie && i < ie[1]; i++) {
569 if ((ie[i + 2] & 0x7f) > rate)
570 rate = ie[i + 2] & 0x7f;
573 ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
574 for (i = 0; ie && i < ie[1]; i++) {
575 if ((ie[i + 2] & 0x7f) > rate)
576 rate = ie[i + 2] & 0x7f;
583 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
587 pos = (const u8 *) (res + 1);
588 end = pos + res->ie_len;
590 while (pos + 1 < end) {
591 if (pos + 2 + pos[1] > end)
602 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
607 pos = (const u8 *) (res + 1);
608 end = pos + res->ie_len;
610 while (pos + 1 < end) {
611 if (pos + 2 + pos[1] > end)
613 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
614 vendor_type == WPA_GET_BE32(&pos[2]))
623 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
629 buf = wpabuf_alloc(res->ie_len);
633 pos = (const u8 *) (res + 1);
634 end = pos + res->ie_len;
636 while (pos + 1 < end) {
637 if (pos + 2 + pos[1] > end)
639 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
640 vendor_type == WPA_GET_BE32(&pos[2]))
641 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
645 if (wpabuf_len(buf) == 0) {
654 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
655 const struct wpa_scan_res *res, u32 vendor_type)
660 if (res->beacon_ie_len == 0)
662 buf = wpabuf_alloc(res->beacon_ie_len);
666 pos = (const u8 *) (res + 1);
668 end = pos + res->beacon_ie_len;
670 while (pos + 1 < end) {
671 if (pos + 2 + pos[1] > end)
673 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
674 vendor_type == WPA_GET_BE32(&pos[2]))
675 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
679 if (wpabuf_len(buf) == 0) {
688 /* Compare function for sorting scan results. Return >0 if @b is considered
690 static int wpa_scan_result_compar(const void *a, const void *b)
692 struct wpa_scan_res **_wa = (void *) a;
693 struct wpa_scan_res **_wb = (void *) b;
694 struct wpa_scan_res *wa = *_wa;
695 struct wpa_scan_res *wb = *_wb;
696 int wpa_a, wpa_b, maxrate_a, maxrate_b;
698 /* WPA/WPA2 support preferred */
699 wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
700 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
701 wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
702 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
709 /* privacy support preferred */
710 if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
711 (wb->caps & IEEE80211_CAP_PRIVACY))
713 if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
714 (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
717 /* best/max rate preferred if signal level close enough XXX */
718 if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
719 (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
720 maxrate_a = wpa_scan_get_max_rate(wa);
721 maxrate_b = wpa_scan_get_max_rate(wb);
722 if (maxrate_a != maxrate_b)
723 return maxrate_b - maxrate_a;
726 /* use freq for channel preference */
728 /* all things being equal, use signal level; if signal levels are
729 * identical, use quality values since some drivers may only report
730 * that value and leave the signal level zero */
731 if (wb->level == wa->level)
732 return wb->qual - wa->qual;
733 return wb->level - wa->level;
738 /* Compare function for sorting scan results when searching a WPS AP for
739 * provisioning. Return >0 if @b is considered better. */
740 static int wpa_scan_result_wps_compar(const void *a, const void *b)
742 struct wpa_scan_res **_wa = (void *) a;
743 struct wpa_scan_res **_wb = (void *) b;
744 struct wpa_scan_res *wa = *_wa;
745 struct wpa_scan_res *wb = *_wb;
746 int uses_wps_a, uses_wps_b;
747 struct wpabuf *wps_a, *wps_b;
750 /* Optimization - check WPS IE existence before allocated memory and
751 * doing full reassembly. */
752 uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
753 uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
754 if (uses_wps_a && !uses_wps_b)
756 if (!uses_wps_a && uses_wps_b)
759 if (uses_wps_a && uses_wps_b) {
760 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
761 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
762 res = wps_ap_priority_compar(wps_a, wps_b);
770 * Do not use current AP security policy as a sorting criteria during
771 * WPS provisioning step since the AP may get reconfigured at the
772 * completion of provisioning.
775 /* all things being equal, use signal level; if signal levels are
776 * identical, use quality values since some drivers may only report
777 * that value and leave the signal level zero */
778 if (wb->level == wa->level)
779 return wb->qual - wa->qual;
780 return wb->level - wa->level;
782 #endif /* CONFIG_WPS */
786 * wpa_supplicant_get_scan_results - Get scan results
787 * @wpa_s: Pointer to wpa_supplicant data
788 * @info: Information about what was scanned or %NULL if not available
789 * @new_scan: Whether a new scan was performed
790 * Returns: Scan results, %NULL on failure
792 * This function request the current scan results from the driver and updates
793 * the local BSS list wpa_s->bss. The caller is responsible for freeing the
794 * results with wpa_scan_results_free().
796 struct wpa_scan_results *
797 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
798 struct scan_info *info, int new_scan)
800 struct wpa_scan_results *scan_res;
802 int (*compar)(const void *, const void *) = wpa_scan_result_compar;
804 if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
805 scan_res = ieee80211_sta_get_scan_results(wpa_s);
807 scan_res = wpa_drv_get_scan_results2(wpa_s);
808 if (scan_res == NULL) {
809 wpa_dbg(wpa_s, MSG_DEBUG, "Failed to get scan results");
814 if (wpas_wps_in_progress(wpa_s)) {
815 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Order scan results with WPS "
816 "provisioning rules");
817 compar = wpa_scan_result_wps_compar;
819 #endif /* CONFIG_WPS */
821 qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
824 wpa_bss_update_start(wpa_s);
825 for (i = 0; i < scan_res->num; i++)
826 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
827 wpa_bss_update_end(wpa_s, info, new_scan);
833 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
835 struct wpa_scan_results *scan_res;
836 scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
837 if (scan_res == NULL)
839 wpa_scan_results_free(scan_res);
845 void wpa_scan_results_free(struct wpa_scan_results *res)
852 for (i = 0; i < res->num; i++)
853 os_free(res->res[i]);