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"
30 static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
32 struct wpa_ssid *ssid;
33 union wpa_event_data data;
35 ssid = wpa_supplicant_get_ssid(wpa_s);
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);
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);
53 static int wpas_wps_in_use(struct wpa_config *conf,
54 enum wps_request_type *req_type)
56 struct wpa_ssid *ssid;
59 for (ssid = conf->ssid; ssid; ssid = ssid->next) {
60 if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
64 *req_type = wpas_wps_get_req_type(ssid);
65 if (!ssid->eap.phase1)
68 if (os_strstr(ssid->eap.phase1, "pbc=1"))
74 #endif /* CONFIG_WPS */
77 int wpa_supplicant_enabled_networks(struct wpa_config *conf)
79 struct wpa_ssid *ssid = conf->ssid;
89 static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
90 struct wpa_ssid *ssid)
98 /* ap_scan=2 mode - try to associate with each SSID. */
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);
107 /* Continue from the next SSID on the next attempt. */
108 wpa_s->prev_scan_ssid = ssid;
110 /* Start from the beginning of the SSID list. */
111 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
113 wpa_supplicant_associate(wpa_s, NULL, ssid);
117 static int int_array_len(const int *a)
120 for (i = 0; a && a[i]; i++)
126 static void int_array_concat(int **res, const int *a)
131 reslen = int_array_len(*res);
132 alen = int_array_len(a);
134 n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
140 for (i = 0; i <= alen; i++)
141 n[reslen + i] = a[i];
146 static int freq_cmp(const void *a, const void *b)
159 static void int_array_sort_unique(int *a)
167 alen = int_array_len(a);
168 qsort(a, alen, sizeof(int), freq_cmp);
172 while (a[i] && a[j]) {
185 int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
186 struct wpa_driver_scan_params *params)
190 wpa_supplicant_notify_scanning(wpa_s, 1);
192 if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
193 ret = ieee80211_sta_req_scan(wpa_s, params);
195 ret = wpa_drv_scan(wpa_s, params);
198 wpa_supplicant_notify_scanning(wpa_s, 0);
199 wpas_notify_scan_done(wpa_s, 0);
207 static struct wpa_driver_scan_filter *
208 wpa_supplicant_build_filter_ssids(struct wpa_config *conf, size_t *num_ssids)
210 struct wpa_driver_scan_filter *ssids;
211 struct wpa_ssid *ssid;
215 if (!conf->filter_ssids)
218 for (count = 0, ssid = conf->ssid; ssid; ssid = ssid->next) {
219 if (ssid->ssid && ssid->ssid_len)
224 ssids = os_zalloc(count * sizeof(struct wpa_driver_scan_filter));
228 for (ssid = conf->ssid; ssid; ssid = ssid->next) {
229 if (!ssid->ssid || !ssid->ssid_len)
231 os_memcpy(ssids[*num_ssids].ssid, ssid->ssid, ssid->ssid_len);
232 ssids[*num_ssids].ssid_len = ssid->ssid_len;
240 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
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;
248 enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
249 #endif /* CONFIG_WPS */
250 struct wpa_driver_scan_params params;
252 enum wpa_states prev_state;
254 if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
255 wpa_printf(MSG_DEBUG, "Skip scan - interface disabled");
259 if (wpa_s->disconnected && !wpa_s->scan_req) {
260 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
264 if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
266 wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
267 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
271 if (wpa_s->conf->ap_scan != 0 &&
272 (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
273 wpa_printf(MSG_DEBUG, "Using wired authentication - "
274 "overriding ap_scan configuration");
275 wpa_s->conf->ap_scan = 0;
276 wpas_notify_ap_scan_changed(wpa_s);
279 if (wpa_s->conf->ap_scan == 0) {
280 wpa_supplicant_gen_assoc_event(wpa_s);
284 if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
285 wpa_s->conf->ap_scan == 2)
288 max_ssids = wpa_s->max_scan_ssids;
289 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
290 max_ssids = WPAS_MAX_SCAN_SSIDS;
294 wps = wpas_wps_in_use(wpa_s->conf, &req_type);
295 #endif /* CONFIG_WPS */
297 scan_req = wpa_s->scan_req;
300 os_memset(¶ms, 0, sizeof(params));
302 prev_state = wpa_s->wpa_state;
303 if (wpa_s->wpa_state == WPA_DISCONNECTED ||
304 wpa_s->wpa_state == WPA_INACTIVE)
305 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
307 /* Find the starting point from which to continue scanning */
308 ssid = wpa_s->conf->ssid;
309 if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
311 if (ssid == wpa_s->prev_scan_ssid) {
319 if (scan_req != 2 && (wpa_s->conf->ap_scan == 2 ||
320 wpa_s->connect_without_scan)) {
321 wpa_s->connect_without_scan = 0;
322 wpa_supplicant_assoc_try(wpa_s, ssid);
324 } else if (wpa_s->conf->ap_scan == 2) {
326 * User-initiated scan request in ap_scan == 2; scan with
331 struct wpa_ssid *start = ssid, *tssid;
333 if (ssid == NULL && max_ssids > 1)
334 ssid = wpa_s->conf->ssid;
336 if (!ssid->disabled && ssid->scan_ssid) {
337 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
338 ssid->ssid, ssid->ssid_len);
339 params.ssids[params.num_ssids].ssid =
341 params.ssids[params.num_ssids].ssid_len =
344 if (params.num_ssids + 1 >= max_ssids)
350 if (ssid == NULL && max_ssids > 1 &&
351 start != wpa_s->conf->ssid)
352 ssid = wpa_s->conf->ssid;
355 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
358 if ((params.freqs || !freqs_set) && tssid->scan_freq) {
359 int_array_concat(¶ms.freqs,
362 os_free(params.freqs);
367 int_array_sort_unique(params.freqs);
371 wpa_s->prev_scan_ssid = ssid;
373 wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
377 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
379 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
381 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
385 if (params.freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
387 * Optimize post-provisioning scan based on channel used
388 * during provisioning.
390 wpa_printf(MSG_DEBUG, "WPS: Scan only frequency %u MHz that "
391 "was used during provisioning", wpa_s->wps_freq);
392 params.freqs = os_zalloc(2 * sizeof(int));
394 params.freqs[0] = wpa_s->wps_freq;
399 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
400 wpa_s->wps->uuid, req_type);
402 params.extra_ies = wpabuf_head(wps_ie);
403 params.extra_ies_len = wpabuf_len(wps_ie);
406 #endif /* CONFIG_WPS */
408 params.filter_ssids = wpa_supplicant_build_filter_ssids(
409 wpa_s->conf, ¶ms.num_filter_ssids);
411 ret = wpa_supplicant_trigger_scan(wpa_s, ¶ms);
414 os_free(params.freqs);
415 os_free(params.filter_ssids);
418 wpa_printf(MSG_WARNING, "Failed to initiate AP scan.");
419 if (prev_state != wpa_s->wpa_state)
420 wpa_supplicant_set_state(wpa_s, prev_state);
421 wpa_supplicant_req_scan(wpa_s, 1, 0);
427 * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
428 * @wpa_s: Pointer to wpa_supplicant data
429 * @sec: Number of seconds after which to scan
430 * @usec: Number of microseconds after which to scan
432 * This function is used to schedule a scan for neighboring access points after
433 * the specified time.
435 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
437 /* If there's at least one network that should be specifically scanned
438 * then don't cancel the scan and reschedule. Some drivers do
439 * background scanning which generates frequent scan results, and that
440 * causes the specific SSID scan to get continually pushed back and
441 * never happen, which causes hidden APs to never get probe-scanned.
443 if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
444 wpa_s->conf->ap_scan == 1) {
445 struct wpa_ssid *ssid = wpa_s->conf->ssid;
448 if (!ssid->disabled && ssid->scan_ssid)
453 wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
454 "ensure that specific SSID scans occur");
459 wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
461 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
462 eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
467 * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
468 * @wpa_s: Pointer to wpa_supplicant data
470 * This function is used to cancel a scan request scheduled with
471 * wpa_supplicant_req_scan().
473 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
475 wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
476 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
480 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
483 if (wpa_s->scanning != scanning) {
484 wpa_s->scanning = scanning;
485 wpas_notify_scanning(wpa_s);
490 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
496 ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
497 for (i = 0; ie && i < ie[1]; i++) {
498 if ((ie[i + 2] & 0x7f) > rate)
499 rate = ie[i + 2] & 0x7f;
502 ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
503 for (i = 0; ie && i < ie[1]; i++) {
504 if ((ie[i + 2] & 0x7f) > rate)
505 rate = ie[i + 2] & 0x7f;
512 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
516 pos = (const u8 *) (res + 1);
517 end = pos + res->ie_len;
519 while (pos + 1 < end) {
520 if (pos + 2 + pos[1] > end)
531 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
536 pos = (const u8 *) (res + 1);
537 end = pos + res->ie_len;
539 while (pos + 1 < end) {
540 if (pos + 2 + pos[1] > end)
542 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
543 vendor_type == WPA_GET_BE32(&pos[2]))
552 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
558 buf = wpabuf_alloc(res->ie_len);
562 pos = (const u8 *) (res + 1);
563 end = pos + res->ie_len;
565 while (pos + 1 < end) {
566 if (pos + 2 + pos[1] > end)
568 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
569 vendor_type == WPA_GET_BE32(&pos[2]))
570 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
574 if (wpabuf_len(buf) == 0) {
583 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
584 const struct wpa_scan_res *res, u32 vendor_type)
589 if (res->beacon_ie_len == 0)
591 buf = wpabuf_alloc(res->beacon_ie_len);
595 pos = (const u8 *) (res + 1);
597 end = pos + res->beacon_ie_len;
599 while (pos + 1 < end) {
600 if (pos + 2 + pos[1] > end)
602 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
603 vendor_type == WPA_GET_BE32(&pos[2]))
604 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
608 if (wpabuf_len(buf) == 0) {
617 /* Compare function for sorting scan results. Return >0 if @b is considered
619 static int wpa_scan_result_compar(const void *a, const void *b)
621 struct wpa_scan_res **_wa = (void *) a;
622 struct wpa_scan_res **_wb = (void *) b;
623 struct wpa_scan_res *wa = *_wa;
624 struct wpa_scan_res *wb = *_wb;
625 int wpa_a, wpa_b, maxrate_a, maxrate_b;
627 /* WPA/WPA2 support preferred */
628 wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
629 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
630 wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
631 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
638 /* privacy support preferred */
639 if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
640 (wb->caps & IEEE80211_CAP_PRIVACY))
642 if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
643 (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
646 /* best/max rate preferred if signal level close enough XXX */
647 if ((wa->level && wb->level && abs(wb->level - wa->level) < 5) ||
648 (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
649 maxrate_a = wpa_scan_get_max_rate(wa);
650 maxrate_b = wpa_scan_get_max_rate(wb);
651 if (maxrate_a != maxrate_b)
652 return maxrate_b - maxrate_a;
655 /* use freq for channel preference */
657 /* all things being equal, use signal level; if signal levels are
658 * identical, use quality values since some drivers may only report
659 * that value and leave the signal level zero */
660 if (wb->level == wa->level)
661 return wb->qual - wa->qual;
662 return wb->level - wa->level;
667 /* Compare function for sorting scan results when searching a WPS AP for
668 * provisioning. Return >0 if @b is considered better. */
669 static int wpa_scan_result_wps_compar(const void *a, const void *b)
671 struct wpa_scan_res **_wa = (void *) a;
672 struct wpa_scan_res **_wb = (void *) b;
673 struct wpa_scan_res *wa = *_wa;
674 struct wpa_scan_res *wb = *_wb;
675 int uses_wps_a, uses_wps_b;
676 struct wpabuf *wps_a, *wps_b;
679 /* Optimization - check WPS IE existence before allocated memory and
680 * doing full reassembly. */
681 uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
682 uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
683 if (uses_wps_a && !uses_wps_b)
685 if (!uses_wps_a && uses_wps_b)
688 if (uses_wps_a && uses_wps_b) {
689 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
690 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
691 res = wps_ap_priority_compar(wps_a, wps_b);
699 * Do not use current AP security policy as a sorting criteria during
700 * WPS provisioning step since the AP may get reconfigured at the
701 * completion of provisioning.
704 /* all things being equal, use signal level; if signal levels are
705 * identical, use quality values since some drivers may only report
706 * that value and leave the signal level zero */
707 if (wb->level == wa->level)
708 return wb->qual - wa->qual;
709 return wb->level - wa->level;
711 #endif /* CONFIG_WPS */
715 * wpa_supplicant_get_scan_results - Get scan results
716 * @wpa_s: Pointer to wpa_supplicant data
717 * @info: Information about what was scanned or %NULL if not available
718 * @new_scan: Whether a new scan was performed
719 * Returns: Scan results, %NULL on failure
721 * This function request the current scan results from the driver and updates
722 * the local BSS list wpa_s->bss. The caller is responsible for freeing the
723 * results with wpa_scan_results_free().
725 struct wpa_scan_results *
726 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
727 struct scan_info *info, int new_scan)
729 struct wpa_scan_results *scan_res;
731 int (*compar)(const void *, const void *) = wpa_scan_result_compar;
733 if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
734 scan_res = ieee80211_sta_get_scan_results(wpa_s);
736 scan_res = wpa_drv_get_scan_results2(wpa_s);
737 if (scan_res == NULL) {
738 wpa_printf(MSG_DEBUG, "Failed to get scan results");
743 if (wpas_wps_in_progress(wpa_s)) {
744 wpa_printf(MSG_DEBUG, "WPS: Order scan results with WPS "
745 "provisioning rules");
746 compar = wpa_scan_result_wps_compar;
748 #endif /* CONFIG_WPS */
750 qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
753 wpa_bss_update_start(wpa_s);
754 for (i = 0; i < scan_res->num; i++)
755 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
756 wpa_bss_update_end(wpa_s, info, new_scan);
762 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
764 struct wpa_scan_results *scan_res;
765 scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
766 if (scan_res == NULL)
768 wpa_scan_results_free(scan_res);
774 void wpa_scan_results_free(struct wpa_scan_results *res)
781 for (i = 0; i < res->num; i++)
782 os_free(res->res[i]);