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"
23 #include "wps_supplicant.h"
24 #include "p2p_supplicant.h"
31 static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
33 struct wpa_ssid *ssid;
34 union wpa_event_data data;
36 ssid = wpa_supplicant_get_ssid(wpa_s);
40 if (wpa_s->current_ssid == NULL) {
41 wpa_s->current_ssid = ssid;
42 if (wpa_s->current_ssid != NULL)
43 wpas_notify_network_changed(wpa_s);
45 wpa_supplicant_initiate_eapol(wpa_s);
46 wpa_dbg(wpa_s, MSG_DEBUG, "Already associated with a configured "
47 "network - generating associated event");
48 os_memset(&data, 0, sizeof(data));
49 wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);
54 static int wpas_wps_in_use(struct wpa_supplicant *wpa_s,
55 enum wps_request_type *req_type)
57 struct wpa_ssid *ssid;
60 for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
61 if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
65 *req_type = wpas_wps_get_req_type(ssid);
66 if (!ssid->eap.phase1)
69 if (os_strstr(ssid->eap.phase1, "pbc=1"))
74 wpa_s->wps->dev.p2p = 1;
77 *req_type = WPS_REQ_ENROLLEE_INFO;
79 #endif /* CONFIG_P2P */
83 #endif /* CONFIG_WPS */
86 int wpa_supplicant_enabled_networks(struct wpa_config *conf)
88 struct wpa_ssid *ssid = conf->ssid;
99 static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
100 struct wpa_ssid *ssid)
108 /* ap_scan=2 mode - try to associate with each SSID. */
110 wpa_dbg(wpa_s, MSG_DEBUG, "wpa_supplicant_assoc_try: Reached "
111 "end of scan list - go back to beginning");
112 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
113 wpa_supplicant_req_scan(wpa_s, 0, 0);
117 /* Continue from the next SSID on the next attempt. */
118 wpa_s->prev_scan_ssid = ssid;
120 /* Start from the beginning of the SSID list. */
121 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
123 wpa_supplicant_associate(wpa_s, NULL, ssid);
127 static int int_array_len(const int *a)
130 for (i = 0; a && a[i]; i++)
136 static void int_array_concat(int **res, const int *a)
141 reslen = int_array_len(*res);
142 alen = int_array_len(a);
144 n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
150 for (i = 0; i <= alen; i++)
151 n[reslen + i] = a[i];
156 static int freq_cmp(const void *a, const void *b)
169 static void int_array_sort_unique(int *a)
177 alen = int_array_len(a);
178 qsort(a, alen, sizeof(int), freq_cmp);
182 while (a[i] && a[j]) {
195 int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
196 struct wpa_driver_scan_params *params)
200 wpa_supplicant_notify_scanning(wpa_s, 1);
202 ret = wpa_drv_scan(wpa_s, params);
204 wpa_supplicant_notify_scanning(wpa_s, 0);
205 wpas_notify_scan_done(wpa_s, 0);
214 wpa_supplicant_delayed_sched_scan_timeout(void *eloop_ctx, void *timeout_ctx)
216 struct wpa_supplicant *wpa_s = eloop_ctx;
218 wpa_dbg(wpa_s, MSG_DEBUG, "Starting delayed sched scan");
220 if (wpa_supplicant_req_sched_scan(wpa_s))
221 wpa_supplicant_req_scan(wpa_s, 0, 0);
226 wpa_supplicant_sched_scan_timeout(void *eloop_ctx, void *timeout_ctx)
228 struct wpa_supplicant *wpa_s = eloop_ctx;
230 wpa_dbg(wpa_s, MSG_DEBUG, "Sched scan timeout - stopping it");
232 wpa_s->sched_scan_timed_out = 1;
233 wpa_supplicant_cancel_sched_scan(wpa_s);
238 wpa_supplicant_start_sched_scan(struct wpa_supplicant *wpa_s,
239 struct wpa_driver_scan_params *params,
244 wpa_supplicant_notify_scanning(wpa_s, 1);
245 ret = wpa_drv_sched_scan(wpa_s, params, interval * 1000);
247 wpa_supplicant_notify_scanning(wpa_s, 0);
249 wpa_s->sched_scanning = 1;
255 static int wpa_supplicant_stop_sched_scan(struct wpa_supplicant *wpa_s)
259 ret = wpa_drv_stop_sched_scan(wpa_s);
261 wpa_dbg(wpa_s, MSG_DEBUG, "stopping sched_scan failed!");
262 /* TODO: what to do if stopping fails? */
270 static struct wpa_driver_scan_filter *
271 wpa_supplicant_build_filter_ssids(struct wpa_config *conf, size_t *num_ssids)
273 struct wpa_driver_scan_filter *ssids;
274 struct wpa_ssid *ssid;
278 if (!conf->filter_ssids)
281 for (count = 0, ssid = conf->ssid; ssid; ssid = ssid->next) {
282 if (ssid->ssid && ssid->ssid_len)
287 ssids = os_zalloc(count * sizeof(struct wpa_driver_scan_filter));
291 for (ssid = conf->ssid; ssid; ssid = ssid->next) {
292 if (!ssid->ssid || !ssid->ssid_len)
294 os_memcpy(ssids[*num_ssids].ssid, ssid->ssid, ssid->ssid_len);
295 ssids[*num_ssids].ssid_len = ssid->ssid_len;
303 static void wpa_supplicant_optimize_freqs(
304 struct wpa_supplicant *wpa_s, struct wpa_driver_scan_params *params)
307 if (params->freqs == NULL && wpa_s->p2p_in_provisioning &&
309 /* Optimize provisioning state scan based on GO information */
310 if (wpa_s->p2p_in_provisioning < 5 &&
311 wpa_s->go_params->freq > 0) {
312 wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only GO "
313 "preferred frequency %d MHz",
314 wpa_s->go_params->freq);
315 params->freqs = os_zalloc(2 * sizeof(int));
317 params->freqs[0] = wpa_s->go_params->freq;
318 } else if (wpa_s->p2p_in_provisioning < 8 &&
319 wpa_s->go_params->freq_list[0]) {
320 wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only common "
322 int_array_concat(¶ms->freqs,
323 wpa_s->go_params->freq_list);
325 int_array_sort_unique(params->freqs);
327 wpa_s->p2p_in_provisioning++;
329 #endif /* CONFIG_P2P */
332 if (params->freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
334 * Optimize post-provisioning scan based on channel used
335 * during provisioning.
337 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Scan only frequency %u MHz "
338 "that was used during provisioning", wpa_s->wps_freq);
339 params->freqs = os_zalloc(2 * sizeof(int));
341 params->freqs[0] = wpa_s->wps_freq;
345 #endif /* CONFIG_WPS */
349 #ifdef CONFIG_INTERWORKING
350 static void wpas_add_interworking_elements(struct wpa_supplicant *wpa_s,
353 if (wpa_s->conf->interworking == 0)
356 wpabuf_put_u8(buf, WLAN_EID_EXT_CAPAB);
357 wpabuf_put_u8(buf, 4);
358 wpabuf_put_u8(buf, 0x00);
359 wpabuf_put_u8(buf, 0x00);
360 wpabuf_put_u8(buf, 0x00);
361 wpabuf_put_u8(buf, 0x80); /* Bit 31 - Interworking */
363 wpabuf_put_u8(buf, WLAN_EID_INTERWORKING);
364 wpabuf_put_u8(buf, is_zero_ether_addr(wpa_s->conf->hessid) ? 1 :
366 wpabuf_put_u8(buf, wpa_s->conf->access_network_type);
368 if (!is_zero_ether_addr(wpa_s->conf->hessid))
369 wpabuf_put_data(buf, wpa_s->conf->hessid, ETH_ALEN);
371 #endif /* CONFIG_INTERWORKING */
374 static struct wpabuf *
375 wpa_supplicant_extra_ies(struct wpa_supplicant *wpa_s,
376 struct wpa_driver_scan_params *params)
378 struct wpabuf *extra_ie = NULL;
381 enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
382 #endif /* CONFIG_WPS */
384 #ifdef CONFIG_INTERWORKING
385 if (wpa_s->conf->interworking &&
386 wpabuf_resize(&extra_ie, 100) == 0)
387 wpas_add_interworking_elements(wpa_s, extra_ie);
388 #endif /* CONFIG_INTERWORKING */
391 wps = wpas_wps_in_use(wpa_s, &req_type);
394 struct wpabuf *wps_ie;
395 wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
396 wpa_s->wps->uuid, req_type,
399 if (wpabuf_resize(&extra_ie, wpabuf_len(wps_ie)) == 0)
400 wpabuf_put_buf(extra_ie, wps_ie);
407 size_t ielen = p2p_scan_ie_buf_len(wpa_s->global->p2p);
408 if (wpabuf_resize(&extra_ie, ielen) == 0)
409 wpas_p2p_scan_ie(wpa_s, extra_ie);
411 #endif /* CONFIG_P2P */
413 #endif /* CONFIG_WPS */
419 static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
421 struct wpa_supplicant *wpa_s = eloop_ctx;
422 struct wpa_ssid *ssid;
423 int scan_req = 0, ret;
424 struct wpabuf *extra_ie;
425 struct wpa_driver_scan_params params;
427 enum wpa_states prev_state;
429 if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
430 wpa_dbg(wpa_s, MSG_DEBUG, "Skip scan - interface disabled");
434 if (wpa_s->disconnected && !wpa_s->scan_req) {
435 wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
439 if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
441 wpa_dbg(wpa_s, MSG_DEBUG, "No enabled networks - do not scan");
442 wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
446 if (wpa_s->conf->ap_scan != 0 &&
447 (wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
448 wpa_dbg(wpa_s, MSG_DEBUG, "Using wired authentication - "
449 "overriding ap_scan configuration");
450 wpa_s->conf->ap_scan = 0;
451 wpas_notify_ap_scan_changed(wpa_s);
454 if (wpa_s->conf->ap_scan == 0) {
455 wpa_supplicant_gen_assoc_event(wpa_s);
460 if (wpas_p2p_in_progress(wpa_s)) {
461 if (wpa_s->wpa_state == WPA_SCANNING) {
462 wpa_dbg(wpa_s, MSG_DEBUG, "Delay station mode scan "
463 "while P2P operation is in progress");
464 wpa_supplicant_req_scan(wpa_s, 5, 0);
466 wpa_dbg(wpa_s, MSG_DEBUG, "Do not request scan while "
467 "P2P operation is in progress");
471 #endif /* CONFIG_P2P */
473 if (wpa_s->conf->ap_scan == 2)
476 max_ssids = wpa_s->max_scan_ssids;
477 if (max_ssids > WPAS_MAX_SCAN_SSIDS)
478 max_ssids = WPAS_MAX_SCAN_SSIDS;
481 scan_req = wpa_s->scan_req;
484 os_memset(¶ms, 0, sizeof(params));
486 prev_state = wpa_s->wpa_state;
487 if (wpa_s->wpa_state == WPA_DISCONNECTED ||
488 wpa_s->wpa_state == WPA_INACTIVE)
489 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
491 if (scan_req != 2 && wpa_s->connect_without_scan) {
492 for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
493 if (ssid == wpa_s->connect_without_scan)
496 wpa_s->connect_without_scan = NULL;
498 wpa_printf(MSG_DEBUG, "Start a pre-selected network "
499 "without scan step");
500 wpa_supplicant_associate(wpa_s, NULL, ssid);
505 /* Find the starting point from which to continue scanning */
506 ssid = wpa_s->conf->ssid;
507 if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
509 if (ssid == wpa_s->prev_scan_ssid) {
517 if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
518 wpa_s->connect_without_scan = NULL;
519 wpa_supplicant_assoc_try(wpa_s, ssid);
521 } else if (wpa_s->conf->ap_scan == 2) {
523 * User-initiated scan request in ap_scan == 2; scan with
528 struct wpa_ssid *start = ssid, *tssid;
530 if (ssid == NULL && max_ssids > 1)
531 ssid = wpa_s->conf->ssid;
533 if (!ssid->disabled && ssid->scan_ssid) {
534 wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
535 ssid->ssid, ssid->ssid_len);
536 params.ssids[params.num_ssids].ssid =
538 params.ssids[params.num_ssids].ssid_len =
541 if (params.num_ssids + 1 >= max_ssids)
547 if (ssid == NULL && max_ssids > 1 &&
548 start != wpa_s->conf->ssid)
549 ssid = wpa_s->conf->ssid;
552 for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
555 if ((params.freqs || !freqs_set) && tssid->scan_freq) {
556 int_array_concat(¶ms.freqs,
559 os_free(params.freqs);
564 int_array_sort_unique(params.freqs);
568 wpa_s->prev_scan_ssid = ssid;
570 wpa_dbg(wpa_s, MSG_DEBUG, "Include wildcard SSID in "
574 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for specific "
577 wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
579 wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for wildcard "
583 wpa_supplicant_optimize_freqs(wpa_s, ¶ms);
584 extra_ie = wpa_supplicant_extra_ies(wpa_s, ¶ms);
586 if (params.freqs == NULL && wpa_s->next_scan_freqs) {
587 wpa_dbg(wpa_s, MSG_DEBUG, "Optimize scan based on previously "
588 "generated frequency list");
589 params.freqs = wpa_s->next_scan_freqs;
591 os_free(wpa_s->next_scan_freqs);
592 wpa_s->next_scan_freqs = NULL;
594 params.filter_ssids = wpa_supplicant_build_filter_ssids(
595 wpa_s->conf, ¶ms.num_filter_ssids);
597 params.extra_ies = wpabuf_head(extra_ie);
598 params.extra_ies_len = wpabuf_len(extra_ie);
602 if (wpa_s->p2p_in_provisioning) {
604 * The interface may not yet be in P2P mode, so we have to
605 * explicitly request P2P probe to disable CCK rates.
607 params.p2p_probe = 1;
609 #endif /* CONFIG_P2P */
611 ret = wpa_supplicant_trigger_scan(wpa_s, ¶ms);
613 wpabuf_free(extra_ie);
614 os_free(params.freqs);
615 os_free(params.filter_ssids);
618 wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate AP scan");
619 if (prev_state != wpa_s->wpa_state)
620 wpa_supplicant_set_state(wpa_s, prev_state);
621 wpa_supplicant_req_scan(wpa_s, 1, 0);
627 * wpa_supplicant_req_scan - Schedule a scan for neighboring access points
628 * @wpa_s: Pointer to wpa_supplicant data
629 * @sec: Number of seconds after which to scan
630 * @usec: Number of microseconds after which to scan
632 * This function is used to schedule a scan for neighboring access points after
633 * the specified time.
635 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
637 /* If there's at least one network that should be specifically scanned
638 * then don't cancel the scan and reschedule. Some drivers do
639 * background scanning which generates frequent scan results, and that
640 * causes the specific SSID scan to get continually pushed back and
641 * never happen, which causes hidden APs to never get probe-scanned.
643 if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
644 wpa_s->conf->ap_scan == 1) {
645 struct wpa_ssid *ssid = wpa_s->conf->ssid;
648 if (!ssid->disabled && ssid->scan_ssid)
653 wpa_dbg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
654 "ensure that specific SSID scans occur");
659 wpa_dbg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
661 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
662 eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
667 * wpa_supplicant_delayed_sched_scan - Request a delayed scheduled scan
668 * @wpa_s: Pointer to wpa_supplicant data
669 * @sec: Number of seconds after which to scan
670 * @usec: Number of microseconds after which to scan
672 * This function is used to schedule periodic scans for neighboring
673 * access points after the specified time.
675 int wpa_supplicant_delayed_sched_scan(struct wpa_supplicant *wpa_s,
678 if (!wpa_s->sched_scan_supported)
681 eloop_register_timeout(sec, usec,
682 wpa_supplicant_delayed_sched_scan_timeout,
690 * wpa_supplicant_req_sched_scan - Start a periodic scheduled scan
691 * @wpa_s: Pointer to wpa_supplicant data
693 * This function is used to schedule periodic scans for neighboring
694 * access points repeating the scan continuously.
696 int wpa_supplicant_req_sched_scan(struct wpa_supplicant *wpa_s)
698 struct wpa_driver_scan_params params;
699 enum wpa_states prev_state;
700 struct wpa_ssid *ssid;
701 struct wpabuf *wps_ie = NULL;
703 unsigned int max_sched_scan_ssids;
705 if (!wpa_s->sched_scan_supported)
708 if (wpa_s->max_sched_scan_ssids > WPAS_MAX_SCAN_SSIDS)
709 max_sched_scan_ssids = WPAS_MAX_SCAN_SSIDS;
711 max_sched_scan_ssids = wpa_s->max_sched_scan_ssids;
713 if (wpa_s->sched_scanning)
716 os_memset(¶ms, 0, sizeof(params));
718 /* If we can't allocate space for the filters, we just don't filter */
719 params.filter_ssids = os_zalloc(wpa_s->max_match_sets *
720 sizeof(struct wpa_driver_scan_filter));
722 prev_state = wpa_s->wpa_state;
723 if (wpa_s->wpa_state == WPA_DISCONNECTED ||
724 wpa_s->wpa_state == WPA_INACTIVE)
725 wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
727 /* Find the starting point from which to continue scanning */
728 ssid = wpa_s->conf->ssid;
729 if (wpa_s->prev_sched_ssid) {
731 if (ssid == wpa_s->prev_sched_ssid) {
739 if (!ssid || !wpa_s->prev_sched_ssid) {
740 wpa_dbg(wpa_s, MSG_DEBUG, "Beginning of SSID list");
742 wpa_s->sched_scan_interval = 2;
743 wpa_s->sched_scan_timeout = max_sched_scan_ssids * 2;
744 wpa_s->first_sched_scan = 1;
745 ssid = wpa_s->conf->ssid;
746 wpa_s->prev_sched_ssid = ssid;
750 if (ssid->disabled) {
751 wpa_s->prev_sched_ssid = ssid;
756 if (params.filter_ssids && ssid->ssid && ssid->ssid_len) {
757 os_memcpy(params.filter_ssids[params.num_filter_ssids].ssid,
758 ssid->ssid, ssid->ssid_len);
759 params.filter_ssids[params.num_filter_ssids].ssid_len =
761 params.num_filter_ssids++;
764 if (ssid->scan_ssid) {
765 params.ssids[params.num_ssids].ssid =
767 params.ssids[params.num_ssids].ssid_len =
770 if (params.num_ssids >= max_sched_scan_ssids) {
771 wpa_s->prev_sched_ssid = ssid;
776 if (params.num_filter_ssids >= wpa_s->max_match_sets)
778 wpa_s->prev_sched_ssid = ssid;
782 if (!params.num_ssids) {
783 os_free(params.filter_ssids);
788 wps_ie = wpa_supplicant_extra_ies(wpa_s, ¶ms);
790 wpa_dbg(wpa_s, MSG_DEBUG,
791 "Starting sched scan: interval %d timeout %d",
792 wpa_s->sched_scan_interval, wpa_s->sched_scan_timeout);
794 ret = wpa_supplicant_start_sched_scan(wpa_s, ¶ms,
795 wpa_s->sched_scan_interval);
797 os_free(params.filter_ssids);
799 wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate sched scan");
800 if (prev_state != wpa_s->wpa_state)
801 wpa_supplicant_set_state(wpa_s, prev_state);
805 /* If we have more SSIDs to scan, add a timeout so we scan them too */
806 if (ssid || !wpa_s->first_sched_scan) {
807 wpa_s->sched_scan_timed_out = 0;
808 eloop_register_timeout(wpa_s->sched_scan_timeout, 0,
809 wpa_supplicant_sched_scan_timeout,
811 wpa_s->first_sched_scan = 0;
812 wpa_s->sched_scan_timeout /= 2;
813 wpa_s->sched_scan_interval *= 2;
821 * wpa_supplicant_cancel_scan - Cancel a scheduled scan request
822 * @wpa_s: Pointer to wpa_supplicant data
824 * This function is used to cancel a scan request scheduled with
825 * wpa_supplicant_req_scan().
827 void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
829 wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling scan request");
830 eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
835 * wpa_supplicant_cancel_sched_scan - Stop running scheduled scans
836 * @wpa_s: Pointer to wpa_supplicant data
838 * This function is used to stop a periodic scheduled scan.
840 void wpa_supplicant_cancel_sched_scan(struct wpa_supplicant *wpa_s)
842 if (!wpa_s->sched_scanning)
845 wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling sched scan");
846 eloop_cancel_timeout(wpa_supplicant_sched_scan_timeout, wpa_s, NULL);
847 wpa_supplicant_stop_sched_scan(wpa_s);
851 void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
854 if (wpa_s->scanning != scanning) {
855 wpa_s->scanning = scanning;
856 wpas_notify_scanning(wpa_s);
861 static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
867 ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
868 for (i = 0; ie && i < ie[1]; i++) {
869 if ((ie[i + 2] & 0x7f) > rate)
870 rate = ie[i + 2] & 0x7f;
873 ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
874 for (i = 0; ie && i < ie[1]; i++) {
875 if ((ie[i + 2] & 0x7f) > rate)
876 rate = ie[i + 2] & 0x7f;
883 const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
887 pos = (const u8 *) (res + 1);
888 end = pos + res->ie_len;
890 while (pos + 1 < end) {
891 if (pos + 2 + pos[1] > end)
902 const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
907 pos = (const u8 *) (res + 1);
908 end = pos + res->ie_len;
910 while (pos + 1 < end) {
911 if (pos + 2 + pos[1] > end)
913 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
914 vendor_type == WPA_GET_BE32(&pos[2]))
923 struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
929 buf = wpabuf_alloc(res->ie_len);
933 pos = (const u8 *) (res + 1);
934 end = pos + res->ie_len;
936 while (pos + 1 < end) {
937 if (pos + 2 + pos[1] > end)
939 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
940 vendor_type == WPA_GET_BE32(&pos[2]))
941 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
945 if (wpabuf_len(buf) == 0) {
954 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
955 const struct wpa_scan_res *res, u32 vendor_type)
960 if (res->beacon_ie_len == 0)
962 buf = wpabuf_alloc(res->beacon_ie_len);
966 pos = (const u8 *) (res + 1);
968 end = pos + res->beacon_ie_len;
970 while (pos + 1 < end) {
971 if (pos + 2 + pos[1] > end)
973 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
974 vendor_type == WPA_GET_BE32(&pos[2]))
975 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
979 if (wpabuf_len(buf) == 0) {
989 * Channels with a great SNR can operate at full rate. What is a great SNR?
990 * This doc https://supportforums.cisco.com/docs/DOC-12954 says, "the general
991 * rule of thumb is that any SNR above 20 is good." This one
992 * http://www.cisco.com/en/US/tech/tk722/tk809/technologies_q_and_a_item09186a00805e9a96.shtml#qa23
993 * recommends 25 as a minimum SNR for 54 Mbps data rate. 30 is chosen here as a
994 * conservative value.
998 /* Compare function for sorting scan results. Return >0 if @b is considered
1000 static int wpa_scan_result_compar(const void *a, const void *b)
1002 #define IS_5GHZ(n) (n > 4000)
1003 #define MIN(a,b) a < b ? a : b
1004 struct wpa_scan_res **_wa = (void *) a;
1005 struct wpa_scan_res **_wb = (void *) b;
1006 struct wpa_scan_res *wa = *_wa;
1007 struct wpa_scan_res *wb = *_wb;
1008 int wpa_a, wpa_b, maxrate_a, maxrate_b;
1011 /* WPA/WPA2 support preferred */
1012 wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
1013 wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
1014 wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
1015 wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
1017 if (wpa_b && !wpa_a)
1019 if (!wpa_b && wpa_a)
1022 /* privacy support preferred */
1023 if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
1024 (wb->caps & IEEE80211_CAP_PRIVACY))
1026 if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
1027 (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
1030 if ((wa->flags & wb->flags & WPA_SCAN_LEVEL_DBM) &&
1031 !((wa->flags | wb->flags) & WPA_SCAN_NOISE_INVALID)) {
1032 snr_a = MIN(wa->level - wa->noise, GREAT_SNR);
1033 snr_b = MIN(wb->level - wb->noise, GREAT_SNR);
1035 /* Not suitable information to calculate SNR, so use level */
1040 /* best/max rate preferred if SNR close enough */
1041 if ((snr_a && snr_b && abs(snr_b - snr_a) < 5) ||
1042 (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
1043 maxrate_a = wpa_scan_get_max_rate(wa);
1044 maxrate_b = wpa_scan_get_max_rate(wb);
1045 if (maxrate_a != maxrate_b)
1046 return maxrate_b - maxrate_a;
1047 if (IS_5GHZ(wa->freq) ^ IS_5GHZ(wb->freq))
1048 return IS_5GHZ(wa->freq) ? -1 : 1;
1051 /* use freq for channel preference */
1053 /* all things being equal, use SNR; if SNRs are
1054 * identical, use quality values since some drivers may only report
1055 * that value and leave the signal level zero */
1057 return wb->qual - wa->qual;
1058 return snr_b - snr_a;
1065 /* Compare function for sorting scan results when searching a WPS AP for
1066 * provisioning. Return >0 if @b is considered better. */
1067 static int wpa_scan_result_wps_compar(const void *a, const void *b)
1069 struct wpa_scan_res **_wa = (void *) a;
1070 struct wpa_scan_res **_wb = (void *) b;
1071 struct wpa_scan_res *wa = *_wa;
1072 struct wpa_scan_res *wb = *_wb;
1073 int uses_wps_a, uses_wps_b;
1074 struct wpabuf *wps_a, *wps_b;
1077 /* Optimization - check WPS IE existence before allocated memory and
1078 * doing full reassembly. */
1079 uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
1080 uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
1081 if (uses_wps_a && !uses_wps_b)
1083 if (!uses_wps_a && uses_wps_b)
1086 if (uses_wps_a && uses_wps_b) {
1087 wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
1088 wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
1089 res = wps_ap_priority_compar(wps_a, wps_b);
1097 * Do not use current AP security policy as a sorting criteria during
1098 * WPS provisioning step since the AP may get reconfigured at the
1099 * completion of provisioning.
1102 /* all things being equal, use signal level; if signal levels are
1103 * identical, use quality values since some drivers may only report
1104 * that value and leave the signal level zero */
1105 if (wb->level == wa->level)
1106 return wb->qual - wa->qual;
1107 return wb->level - wa->level;
1109 #endif /* CONFIG_WPS */
1112 static void dump_scan_res(struct wpa_scan_results *scan_res)
1116 if (scan_res->res == NULL || scan_res->num == 0)
1119 wpa_printf(MSG_EXCESSIVE, "Sorted scan results");
1121 for (i = 0; i < scan_res->num; i++) {
1122 struct wpa_scan_res *r = scan_res->res[i];
1123 if ((r->flags & (WPA_SCAN_LEVEL_DBM | WPA_SCAN_NOISE_INVALID))
1124 == WPA_SCAN_LEVEL_DBM) {
1125 int snr = r->level - r->noise;
1126 wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
1127 "noise=%d level=%d snr=%d%s flags=0x%x",
1128 MAC2STR(r->bssid), r->freq, r->qual,
1129 r->noise, r->level, snr,
1130 snr >= GREAT_SNR ? "*" : "", r->flags);
1132 wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
1133 "noise=%d level=%d flags=0x%x",
1134 MAC2STR(r->bssid), r->freq, r->qual,
1135 r->noise, r->level, r->flags);
1142 * wpa_supplicant_get_scan_results - Get scan results
1143 * @wpa_s: Pointer to wpa_supplicant data
1144 * @info: Information about what was scanned or %NULL if not available
1145 * @new_scan: Whether a new scan was performed
1146 * Returns: Scan results, %NULL on failure
1148 * This function request the current scan results from the driver and updates
1149 * the local BSS list wpa_s->bss. The caller is responsible for freeing the
1150 * results with wpa_scan_results_free().
1152 struct wpa_scan_results *
1153 wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
1154 struct scan_info *info, int new_scan)
1156 struct wpa_scan_results *scan_res;
1158 int (*compar)(const void *, const void *) = wpa_scan_result_compar;
1160 scan_res = wpa_drv_get_scan_results2(wpa_s);
1161 if (scan_res == NULL) {
1162 wpa_dbg(wpa_s, MSG_DEBUG, "Failed to get scan results");
1167 if (wpas_wps_in_progress(wpa_s)) {
1168 wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Order scan results with WPS "
1169 "provisioning rules");
1170 compar = wpa_scan_result_wps_compar;
1172 #endif /* CONFIG_WPS */
1174 qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
1176 dump_scan_res(scan_res);
1178 wpa_bss_update_start(wpa_s);
1179 for (i = 0; i < scan_res->num; i++)
1180 wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
1181 wpa_bss_update_end(wpa_s, info, new_scan);
1187 int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
1189 struct wpa_scan_results *scan_res;
1190 scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
1191 if (scan_res == NULL)
1193 wpa_scan_results_free(scan_res);