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 if (params.freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
389 * Optimize post-provisioning scan based on channel used
390 * during provisioning.
392 wpa_printf(MSG_DEBUG, "WPS: Scan only frequency %u MHz that "
393 "was used during provisioning", wpa_s->wps_freq);
394 params.freqs = os_zalloc(2 * sizeof(int));
396 params.freqs[0] = wpa_s->wps_freq;
401 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
402 wpa_s->wps->uuid, req_type);
404 params.extra_ies = wpabuf_head(wps_ie);
405 params.extra_ies_len = wpabuf_len(wps_ie);
408 #endif /* CONFIG_WPS */
412 if (wpabuf_resize(&wps_ie, 100) == 0) {
413 wpas_p2p_scan_ie(wpa_s, wps_ie);
414 params.extra_ies = wpabuf_head(wps_ie);
415 params.extra_ies_len = wpabuf_len(wps_ie);
418 #endif /* CONFIG_P2P */
420 params.filter_ssids = wpa_supplicant_build_filter_ssids(
421 wpa_s->conf, ¶ms.num_filter_ssids);
423 ret = wpa_supplicant_trigger_scan(wpa_s, ¶ms);
426 os_free(params.freqs);
427 os_free(params.filter_ssids);
430 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
431 if (prev_state != wpa_s->wpa_state)
432 wpa_supplicant_set_state(wpa_s, prev_state);
433 wpa_supplicant_req_scan(wpa_s, 1, 0);
439 * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
440 * @wpa_s: Pointer to wpa_supplicant data
441 * @sec: Number of seconds after which to scan
442 * @usec: Number of microseconds after which to scan
444 * This function is used to schedule a scan for neighboring access points after
445 * the specified time.
447 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
449 /* If there's at least one network that should be specifically scanned
450 * then don't cancel the scan and reschedule. Some drivers do
451 * background scanning which generates frequent scan results, and that
452 * causes the specific SSID scan to get continually pushed back and
453 * never happen, which causes hidden APs to never get probe-scanned.
455 if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
456 wpa_s->conf->ap_scan == 1) {
457 struct wpa_ssid *ssid = wpa_s->conf->ssid;
460 if (!ssid->disabled && ssid->scan_ssid)
465 wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
466 "ensure that specific SSID scans occur");
471 wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
473 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
474 eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
479 * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
480 * @wpa_s: Pointer to wpa_supplicant data
482 * This function is used to cancel a scan request scheduled with
483 * wpa_supplicant_req_scan().
485 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
487 wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
488 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
492 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
495 if (wpa_s->scanning != scanning) {
496 wpa_s->scanning = scanning;
497 wpas_notify_scanning(wpa_s);
502 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
508 ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
509 for (i = 0; ie && i < ie[1]; i++) {
510 if ((ie[i + 2] & 0x7f) > rate)
511 rate = ie[i + 2] & 0x7f;
514 ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
515 for (i = 0; ie && i < ie[1]; i++) {
516 if ((ie[i + 2] & 0x7f) > rate)
517 rate = ie[i + 2] & 0x7f;
524 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
528 pos = (const u8 *) (res + 1);
529 end = pos + res->ie_len;
531 while (pos + 1 < end) {
532 if (pos + 2 + pos[1] > end)
543 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
548 pos = (const u8 *) (res + 1);
549 end = pos + res->ie_len;
551 while (pos + 1 < end) {
552 if (pos + 2 + pos[1] > end)
554 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
555 vendor_type == WPA_GET_BE32(&pos[2]))
564 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
570 buf = wpabuf_alloc(res->ie_len);
574 pos = (const u8 *) (res + 1);
575 end = pos + res->ie_len;
577 while (pos + 1 < end) {
578 if (pos + 2 + pos[1] > end)
580 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
581 vendor_type == WPA_GET_BE32(&pos[2]))
582 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
586 if (wpabuf_len(buf) == 0) {
595 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
596 const struct wpa_scan_res *res, u32 vendor_type)
601 if (res->beacon_ie_len == 0)
603 buf = wpabuf_alloc(res->beacon_ie_len);
607 pos = (const u8 *) (res + 1);
609 end = pos + res->beacon_ie_len;
611 while (pos + 1 < end) {
612 if (pos + 2 + pos[1] > end)
614 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
615 vendor_type == WPA_GET_BE32(&pos[2]))
616 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
620 if (wpabuf_len(buf) == 0) {
629 /* Compare function for sorting scan results. Return >0 if @b is considered
631 static int wpa_scan_result_compar(const void *a, const void *b)
633 struct wpa_scan_res **_wa = (void *) a;
634 struct wpa_scan_res **_wb = (void *) b;
635 struct wpa_scan_res *wa = *_wa;
636 struct wpa_scan_res *wb = *_wb;
637 int wpa_a, wpa_b, maxrate_a, maxrate_b;
639 /* WPA/WPA2 support preferred */
640 wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
641 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
642 wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
643 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
650 /* privacy support preferred */
651 if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
652 (wb->caps & IEEE80211_CAP_PRIVACY))
654 if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
655 (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
658 /* best/max rate preferred if signal level close enough XXX */
659 if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
660 (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
661 maxrate_a = wpa_scan_get_max_rate(wa);
662 maxrate_b = wpa_scan_get_max_rate(wb);
663 if (maxrate_a != maxrate_b)
664 return maxrate_b - maxrate_a;
667 /* use freq for channel preference */
669 /* all things being equal, use signal level; if signal levels are
670 * identical, use quality values since some drivers may only report
671 * that value and leave the signal level zero */
672 if (wb->level == wa->level)
673 return wb->qual - wa->qual;
674 return wb->level - wa->level;
679 /* Compare function for sorting scan results when searching a WPS AP for
680 * provisioning. Return >0 if @b is considered better. */
681 static int wpa_scan_result_wps_compar(const void *a, const void *b)
683 struct wpa_scan_res **_wa = (void *) a;
684 struct wpa_scan_res **_wb = (void *) b;
685 struct wpa_scan_res *wa = *_wa;
686 struct wpa_scan_res *wb = *_wb;
687 int uses_wps_a, uses_wps_b;
688 struct wpabuf *wps_a, *wps_b;
691 /* Optimization - check WPS IE existence before allocated memory and
692 * doing full reassembly. */
693 uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
694 uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
695 if (uses_wps_a && !uses_wps_b)
697 if (!uses_wps_a && uses_wps_b)
700 if (uses_wps_a && uses_wps_b) {
701 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
702 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
703 res = wps_ap_priority_compar(wps_a, wps_b);
711 * Do not use current AP security policy as a sorting criteria during
712 * WPS provisioning step since the AP may get reconfigured at the
713 * completion of provisioning.
716 /* all things being equal, use signal level; if signal levels are
717 * identical, use quality values since some drivers may only report
718 * that value and leave the signal level zero */
719 if (wb->level == wa->level)
720 return wb->qual - wa->qual;
721 return wb->level - wa->level;
723 #endif /* CONFIG_WPS */
727 * wpa_supplicant_get_scan_results - Get scan results
728 * @wpa_s: Pointer to wpa_supplicant data
729 * @info: Information about what was scanned or %NULL if not available
730 * @new_scan: Whether a new scan was performed
731 * Returns: Scan results, %NULL on failure
733 * This function request the current scan results from the driver and updates
734 * the local BSS list wpa_s->bss. The caller is responsible for freeing the
735 * results with wpa_scan_results_free().
737 struct wpa_scan_results *
738 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
739 struct scan_info *info, int new_scan)
741 struct wpa_scan_results *scan_res;
743 int (*compar)(const void *, const void *) = wpa_scan_result_compar;
745 if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
746 scan_res = ieee80211_sta_get_scan_results(wpa_s);
748 scan_res = wpa_drv_get_scan_results2(wpa_s);
749 if (scan_res == NULL) {
750 wpa_printf(MSG_DEBUG, "Failed to get scan results");
755 if (wpas_wps_in_progress(wpa_s)) {
756 wpa_printf(MSG_DEBUG, "WPS: Order scan results with WPS "
757 "provisioning rules");
758 compar = wpa_scan_result_wps_compar;
760 #endif /* CONFIG_WPS */
762 qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
765 wpa_bss_update_start(wpa_s);
766 for (i = 0; i < scan_res->num; i++)
767 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
768 wpa_bss_update_end(wpa_s, info, new_scan);
774 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
776 struct wpa_scan_results *scan_res;
777 scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
778 if (scan_res == NULL)
780 wpa_scan_results_free(scan_res);
786 void wpa_scan_results_free(struct wpa_scan_results *res)
793 for (i = 0; i < res->num; i++)
794 os_free(res->res[i]);