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->disconnected && !wpa_s->scan_req) {
255 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
259 if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
261 wpa_printf(MSG_DEBUG, "No enabled networks - do not scan");
262 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
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);
274 if (wpa_s->conf->ap_scan == 0) {
275 wpa_supplicant_gen_assoc_event(wpa_s);
279 if ((wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME) ||
280 wpa_s->conf->ap_scan == 2)
283 max_ssids = wpa_s->max_scan_ssids;
284 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
285 max_ssids = WPAS_MAX_SCAN_SSIDS;
289 wps = wpas_wps_in_use(wpa_s->conf, &req_type);
290 #endif /* CONFIG_WPS */
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);
303 scan_req = wpa_s->scan_req;
306 os_memset(¶ms, 0, sizeof(params));
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);
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) {
317 if (ssid == wpa_s->prev_scan_ssid) {
325 if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
326 wpa_supplicant_assoc_try(wpa_s, ssid);
328 } else if (wpa_s->conf->ap_scan == 2) {
330 * User-initiated scan request in ap_scan == 2; scan with
335 struct wpa_ssid *start = ssid, *tssid;
337 if (ssid == NULL && max_ssids > 1)
338 ssid = wpa_s->conf->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 =
345 params.ssids[params.num_ssids].ssid_len =
348 if (params.num_ssids + 1 >= max_ssids)
354 if (ssid == NULL && max_ssids > 1 &&
355 start != wpa_s->conf->ssid)
356 ssid = wpa_s->conf->ssid;
359 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
362 if ((params.freqs || !freqs_set) && tssid->scan_freq) {
363 int_array_concat(¶ms.freqs,
366 os_free(params.freqs);
371 int_array_sort_unique(params.freqs);
375 wpa_s->prev_scan_ssid = ssid;
377 wpa_printf(MSG_DEBUG, "Include wildcard SSID in the "
381 wpa_printf(MSG_DEBUG, "Starting AP scan for specific SSID(s)");
383 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
385 wpa_printf(MSG_DEBUG, "Starting AP scan for wildcard SSID");
390 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
391 wpa_s->wps->uuid, req_type);
393 params.extra_ies = wpabuf_head(wps_ie);
394 params.extra_ies_len = wpabuf_len(wps_ie);
397 #endif /* CONFIG_WPS */
399 params.filter_ssids = wpa_supplicant_build_filter_ssids(
400 wpa_s->conf, ¶ms.num_filter_ssids);
402 ret = wpa_supplicant_trigger_scan(wpa_s, ¶ms);
405 os_free(params.freqs);
406 os_free(params.filter_ssids);
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);
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
424 * This function is used to schedule a scan for neighboring access points after
425 * the specified time.
427 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
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.
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;
440 if (!ssid->disabled && ssid->scan_ssid)
445 wpa_msg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
446 "ensure that specific SSID scans occur");
451 wpa_msg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
453 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
454 eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
459 * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
460 * @wpa_s: Pointer to wpa_supplicant data
462 * This function is used to cancel a scan request scheduled with
463 * wpa_supplicant_req_scan().
465 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
467 wpa_msg(wpa_s, MSG_DEBUG, "Cancelling scan request");
468 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
472 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
475 if (wpa_s->scanning != scanning) {
476 wpa_s->scanning = scanning;
477 wpas_notify_scanning(wpa_s);
482 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
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;
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;
504 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
508 pos = (const u8 *) (res + 1);
509 end = pos + res->ie_len;
511 while (pos + 1 < end) {
512 if (pos + 2 + pos[1] > end)
523 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
528 pos = (const u8 *) (res + 1);
529 end = pos + res->ie_len;
531 while (pos + 1 < end) {
532 if (pos + 2 + pos[1] > end)
534 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
535 vendor_type == WPA_GET_BE32(&pos[2]))
544 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
550 buf = wpabuf_alloc(res->ie_len);
554 pos = (const u8 *) (res + 1);
555 end = pos + res->ie_len;
557 while (pos + 1 < end) {
558 if (pos + 2 + pos[1] > end)
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);
566 if (wpabuf_len(buf) == 0) {
575 /* Compare function for sorting scan results. Return >0 if @b is considered
577 static int wpa_scan_result_compar(const void *a, const void *b)
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;
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;
596 /* privacy support preferred */
597 if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
598 (wb->caps & IEEE80211_CAP_PRIVACY))
600 if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
601 (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
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;
613 /* use freq for channel preference */
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;
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
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().
635 struct wpa_scan_results *
636 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
637 struct scan_info *info, int new_scan)
639 struct wpa_scan_results *scan_res;
642 if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_USER_SPACE_MLME)
643 scan_res = ieee80211_sta_get_scan_results(wpa_s);
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");
651 qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
652 wpa_scan_result_compar);
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);
663 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
665 struct wpa_scan_results *scan_res;
666 scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
667 if (scan_res == NULL)
669 wpa_scan_results_free(scan_res);
675 void wpa_scan_results_free(struct wpa_scan_results *res)
682 for (i = 0; i < res->num; i++)
683 os_free(res->res[i]);