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hostap/wpa_supplicant/scan.c
Jouni Malinen b55aca4672 Fix sched_scan for max-num-of-scan_ssid=1 networks 
When the network configuration includes exactly the number of
scan_ssid=1 networks as the driver supports for scan_sched and no
networks need wildcard SSID scan, there is no need to use sched_scan
timeout. Check this condition and optimize this case to avoid the extra
sched_scan start/stop operations.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
2012-04-17 16:51:09 +03:00

1360 lines
34 KiB
C
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/*
* WPA Supplicant - Scanning
* Copyright (c) 2003-2010, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "utils/includes.h"
#include "utils/common.h"
#include "utils/eloop.h"
#include "common/ieee802_11_defs.h"
#include "config.h"
#include "wpa_supplicant_i.h"
#include "driver_i.h"
#include "wps_supplicant.h"
#include "p2p_supplicant.h"
#include "p2p/p2p.h"
#include "notify.h"
#include "bss.h"
#include "scan.h"
static void wpa_supplicant_gen_assoc_event(struct wpa_supplicant *wpa_s)
{
struct wpa_ssid *ssid;
union wpa_event_data data;
ssid = wpa_supplicant_get_ssid(wpa_s);
if (ssid == NULL)
return;
if (wpa_s->current_ssid == NULL) {
wpa_s->current_ssid = ssid;
if (wpa_s->current_ssid != NULL)
wpas_notify_network_changed(wpa_s);
}
wpa_supplicant_initiate_eapol(wpa_s);
wpa_dbg(wpa_s, MSG_DEBUG, "Already associated with a configured "
"network - generating associated event");
os_memset(&data, 0, sizeof(data));
wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);
}
#ifdef CONFIG_WPS
static int wpas_wps_in_use(struct wpa_supplicant *wpa_s,
enum wps_request_type *req_type)
{
struct wpa_ssid *ssid;
int wps = 0;
for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
if (!(ssid->key_mgmt & WPA_KEY_MGMT_WPS))
continue;
wps = 1;
*req_type = wpas_wps_get_req_type(ssid);
if (!ssid->eap.phase1)
continue;
if (os_strstr(ssid->eap.phase1, "pbc=1"))
return 2;
}
#ifdef CONFIG_P2P
if (!wpa_s->global->p2p_disabled && wpa_s->global->p2p) {
wpa_s->wps->dev.p2p = 1;
if (!wps) {
wps = 1;
*req_type = WPS_REQ_ENROLLEE_INFO;
}
}
#endif /* CONFIG_P2P */
return wps;
}
#endif /* CONFIG_WPS */
int wpa_supplicant_enabled_networks(struct wpa_config *conf)
{
struct wpa_ssid *ssid = conf->ssid;
int count = 0;
while (ssid) {
if (!ssid->disabled)
count++;
ssid = ssid->next;
}
return count;
}
static void wpa_supplicant_assoc_try(struct wpa_supplicant *wpa_s,
struct wpa_ssid *ssid)
{
while (ssid) {
if (!ssid->disabled)
break;
ssid = ssid->next;
}
/* ap_scan=2 mode - try to associate with each SSID. */
if (ssid == NULL) {
wpa_dbg(wpa_s, MSG_DEBUG, "wpa_supplicant_assoc_try: Reached "
"end of scan list - go back to beginning");
wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
wpa_supplicant_req_scan(wpa_s, 0, 0);
return;
}
if (ssid->next) {
/* Continue from the next SSID on the next attempt. */
wpa_s->prev_scan_ssid = ssid;
} else {
/* Start from the beginning of the SSID list. */
wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
}
wpa_supplicant_associate(wpa_s, NULL, ssid);
}
static int int_array_len(const int *a)
{
int i;
for (i = 0; a && a[i]; i++)
;
return i;
}
static void int_array_concat(int **res, const int *a)
{
int reslen, alen, i;
int *n;
reslen = int_array_len(*res);
alen = int_array_len(a);
n = os_realloc(*res, (reslen + alen + 1) * sizeof(int));
if (n == NULL) {
os_free(*res);
*res = NULL;
return;
}
for (i = 0; i <= alen; i++)
n[reslen + i] = a[i];
*res = n;
}
static int freq_cmp(const void *a, const void *b)
{
int _a = *(int *) a;
int _b = *(int *) b;
if (_a == 0)
return 1;
if (_b == 0)
return -1;
return _a - _b;
}
static void int_array_sort_unique(int *a)
{
int alen;
int i, j;
if (a == NULL)
return;
alen = int_array_len(a);
qsort(a, alen, sizeof(int), freq_cmp);
i = 0;
j = 1;
while (a[i] && a[j]) {
if (a[i] == a[j]) {
j++;
continue;
}
a[++i] = a[j++];
}
if (a[i])
i++;
a[i] = 0;
}
int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
struct wpa_driver_scan_params *params)
{
int ret;
wpa_supplicant_notify_scanning(wpa_s, 1);
ret = wpa_drv_scan(wpa_s, params);
if (ret) {
wpa_supplicant_notify_scanning(wpa_s, 0);
wpas_notify_scan_done(wpa_s, 0);
} else {
wpa_s->scan_runs++;
wpa_s->normal_scans++;
}
return ret;
}
static void
wpa_supplicant_delayed_sched_scan_timeout(void *eloop_ctx, void *timeout_ctx)
{
struct wpa_supplicant *wpa_s = eloop_ctx;
wpa_dbg(wpa_s, MSG_DEBUG, "Starting delayed sched scan");
if (wpa_supplicant_req_sched_scan(wpa_s))
wpa_supplicant_req_scan(wpa_s, 0, 0);
}
static void
wpa_supplicant_sched_scan_timeout(void *eloop_ctx, void *timeout_ctx)
{
struct wpa_supplicant *wpa_s = eloop_ctx;
wpa_dbg(wpa_s, MSG_DEBUG, "Sched scan timeout - stopping it");
wpa_s->sched_scan_timed_out = 1;
wpa_supplicant_cancel_sched_scan(wpa_s);
}
static int
wpa_supplicant_start_sched_scan(struct wpa_supplicant *wpa_s,
struct wpa_driver_scan_params *params,
int interval)
{
int ret;
wpa_supplicant_notify_scanning(wpa_s, 1);
ret = wpa_drv_sched_scan(wpa_s, params, interval * 1000);
if (ret)
wpa_supplicant_notify_scanning(wpa_s, 0);
else
wpa_s->sched_scanning = 1;
return ret;
}
static int wpa_supplicant_stop_sched_scan(struct wpa_supplicant *wpa_s)
{
int ret;
ret = wpa_drv_stop_sched_scan(wpa_s);
if (ret) {
wpa_dbg(wpa_s, MSG_DEBUG, "stopping sched_scan failed!");
/* TODO: what to do if stopping fails? */
return -1;
}
return ret;
}
static struct wpa_driver_scan_filter *
wpa_supplicant_build_filter_ssids(struct wpa_config *conf, size_t *num_ssids)
{
struct wpa_driver_scan_filter *ssids;
struct wpa_ssid *ssid;
size_t count;
*num_ssids = 0;
if (!conf->filter_ssids)
return NULL;
for (count = 0, ssid = conf->ssid; ssid; ssid = ssid->next) {
if (ssid->ssid && ssid->ssid_len)
count++;
}
if (count == 0)
return NULL;
ssids = os_zalloc(count * sizeof(struct wpa_driver_scan_filter));
if (ssids == NULL)
return NULL;
for (ssid = conf->ssid; ssid; ssid = ssid->next) {
if (!ssid->ssid || !ssid->ssid_len)
continue;
os_memcpy(ssids[*num_ssids].ssid, ssid->ssid, ssid->ssid_len);
ssids[*num_ssids].ssid_len = ssid->ssid_len;
(*num_ssids)++;
}
return ssids;
}
static void wpa_supplicant_optimize_freqs(
struct wpa_supplicant *wpa_s, struct wpa_driver_scan_params *params)
{
#ifdef CONFIG_P2P
if (params->freqs == NULL && wpa_s->p2p_in_provisioning &&
wpa_s->go_params) {
/* Optimize provisioning state scan based on GO information */
if (wpa_s->p2p_in_provisioning < 5 &&
wpa_s->go_params->freq > 0) {
wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only GO "
"preferred frequency %d MHz",
wpa_s->go_params->freq);
params->freqs = os_zalloc(2 * sizeof(int));
if (params->freqs)
params->freqs[0] = wpa_s->go_params->freq;
} else if (wpa_s->p2p_in_provisioning < 8 &&
wpa_s->go_params->freq_list[0]) {
wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only common "
"channels");
int_array_concat(&params->freqs,
wpa_s->go_params->freq_list);
if (params->freqs)
int_array_sort_unique(params->freqs);
}
wpa_s->p2p_in_provisioning++;
}
#endif /* CONFIG_P2P */
#ifdef CONFIG_WPS
if (params->freqs == NULL && wpa_s->after_wps && wpa_s->wps_freq) {
/*
* Optimize post-provisioning scan based on channel used
* during provisioning.
*/
wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Scan only frequency %u MHz "
"that was used during provisioning", wpa_s->wps_freq);
params->freqs = os_zalloc(2 * sizeof(int));
if (params->freqs)
params->freqs[0] = wpa_s->wps_freq;
wpa_s->after_wps--;
}
if (params->freqs == NULL && wpa_s->known_wps_freq && wpa_s->wps_freq)
{
/* Optimize provisioning scan based on already known channel */
wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Scan only frequency %u MHz",
wpa_s->wps_freq);
params->freqs = os_zalloc(2 * sizeof(int));
if (params->freqs)
params->freqs[0] = wpa_s->wps_freq;
wpa_s->known_wps_freq = 0; /* only do this once */
}
#endif /* CONFIG_WPS */
}
#ifdef CONFIG_INTERWORKING
static void wpas_add_interworking_elements(struct wpa_supplicant *wpa_s,
struct wpabuf *buf)
{
if (wpa_s->conf->interworking == 0)
return;
wpabuf_put_u8(buf, WLAN_EID_EXT_CAPAB);
wpabuf_put_u8(buf, 4);
wpabuf_put_u8(buf, 0x00);
wpabuf_put_u8(buf, 0x00);
wpabuf_put_u8(buf, 0x00);
wpabuf_put_u8(buf, 0x80); /* Bit 31 - Interworking */
wpabuf_put_u8(buf, WLAN_EID_INTERWORKING);
wpabuf_put_u8(buf, is_zero_ether_addr(wpa_s->conf->hessid) ? 1 :
1 + ETH_ALEN);
wpabuf_put_u8(buf, wpa_s->conf->access_network_type);
/* No Venue Info */
if (!is_zero_ether_addr(wpa_s->conf->hessid))
wpabuf_put_data(buf, wpa_s->conf->hessid, ETH_ALEN);
}
#endif /* CONFIG_INTERWORKING */
static struct wpabuf *
wpa_supplicant_extra_ies(struct wpa_supplicant *wpa_s,
struct wpa_driver_scan_params *params)
{
struct wpabuf *extra_ie = NULL;
#ifdef CONFIG_WPS
int wps = 0;
enum wps_request_type req_type = WPS_REQ_ENROLLEE_INFO;
#endif /* CONFIG_WPS */
#ifdef CONFIG_INTERWORKING
if (wpa_s->conf->interworking &&
wpabuf_resize(&extra_ie, 100) == 0)
wpas_add_interworking_elements(wpa_s, extra_ie);
#endif /* CONFIG_INTERWORKING */
#ifdef CONFIG_WPS
wps = wpas_wps_in_use(wpa_s, &req_type);
if (wps) {
struct wpabuf *wps_ie;
wps_ie = wps_build_probe_req_ie(wps == 2 ? DEV_PW_PUSHBUTTON :
DEV_PW_DEFAULT,
&wpa_s->wps->dev,
wpa_s->wps->uuid, req_type,
0, NULL);
if (wps_ie) {
if (wpabuf_resize(&extra_ie, wpabuf_len(wps_ie)) == 0)
wpabuf_put_buf(extra_ie, wps_ie);
wpabuf_free(wps_ie);
}
}
#ifdef CONFIG_P2P
if (wps) {
size_t ielen = p2p_scan_ie_buf_len(wpa_s->global->p2p);
if (wpabuf_resize(&extra_ie, ielen) == 0)
wpas_p2p_scan_ie(wpa_s, extra_ie);
}
#endif /* CONFIG_P2P */
#endif /* CONFIG_WPS */
return extra_ie;
}
static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
{
struct wpa_supplicant *wpa_s = eloop_ctx;
struct wpa_ssid *ssid;
int scan_req = 0, ret;
struct wpabuf *extra_ie;
struct wpa_driver_scan_params params;
size_t max_ssids;
enum wpa_states prev_state;
if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
wpa_dbg(wpa_s, MSG_DEBUG, "Skip scan - interface disabled");
return;
}
if (wpa_s->disconnected && !wpa_s->scan_req) {
wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);
return;
}
if (!wpa_supplicant_enabled_networks(wpa_s->conf) &&
!wpa_s->scan_req) {
wpa_dbg(wpa_s, MSG_DEBUG, "No enabled networks - do not scan");
wpa_supplicant_set_state(wpa_s, WPA_INACTIVE);
return;
}
if (wpa_s->conf->ap_scan != 0 &&
(wpa_s->drv_flags & WPA_DRIVER_FLAGS_WIRED)) {
wpa_dbg(wpa_s, MSG_DEBUG, "Using wired authentication - "
"overriding ap_scan configuration");
wpa_s->conf->ap_scan = 0;
wpas_notify_ap_scan_changed(wpa_s);
}
if (wpa_s->conf->ap_scan == 0) {
wpa_supplicant_gen_assoc_event(wpa_s);
return;
}
#ifdef CONFIG_P2P
if (wpas_p2p_in_progress(wpa_s)) {
if (wpa_s->wpa_state == WPA_SCANNING) {
wpa_dbg(wpa_s, MSG_DEBUG, "Delay station mode scan "
"while P2P operation is in progress");
wpa_supplicant_req_scan(wpa_s, 5, 0);
} else {
wpa_dbg(wpa_s, MSG_DEBUG, "Do not request scan while "
"P2P operation is in progress");
}
return;
}
#endif /* CONFIG_P2P */
if (wpa_s->conf->ap_scan == 2)
max_ssids = 1;
else {
max_ssids = wpa_s->max_scan_ssids;
if (max_ssids > WPAS_MAX_SCAN_SSIDS)
max_ssids = WPAS_MAX_SCAN_SSIDS;
}
scan_req = wpa_s->scan_req;
wpa_s->scan_req = 0;
os_memset(&params, 0, sizeof(params));
prev_state = wpa_s->wpa_state;
if (wpa_s->wpa_state == WPA_DISCONNECTED ||
wpa_s->wpa_state == WPA_INACTIVE)
wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
if (scan_req != 2 && wpa_s->connect_without_scan) {
for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
if (ssid == wpa_s->connect_without_scan)
break;
}
wpa_s->connect_without_scan = NULL;
if (ssid) {
wpa_printf(MSG_DEBUG, "Start a pre-selected network "
"without scan step");
wpa_supplicant_associate(wpa_s, NULL, ssid);
return;
}
}
#ifdef CONFIG_P2P
if ((wpa_s->p2p_in_provisioning || wpa_s->show_group_started) &&
wpa_s->go_params) {
wpa_printf(MSG_DEBUG, "P2P: Use specific SSID for scan during "
"P2P group formation");
params.ssids[0].ssid = wpa_s->go_params->ssid;
params.ssids[0].ssid_len = wpa_s->go_params->ssid_len;
params.num_ssids = 1;
goto ssid_list_set;
}
#endif /* CONFIG_P2P */
/* Find the starting point from which to continue scanning */
ssid = wpa_s->conf->ssid;
if (wpa_s->prev_scan_ssid != WILDCARD_SSID_SCAN) {
while (ssid) {
if (ssid == wpa_s->prev_scan_ssid) {
ssid = ssid->next;
break;
}
ssid = ssid->next;
}
}
if (scan_req != 2 && wpa_s->conf->ap_scan == 2) {
wpa_s->connect_without_scan = NULL;
wpa_s->prev_scan_wildcard = 0;
wpa_supplicant_assoc_try(wpa_s, ssid);
return;
} else if (wpa_s->conf->ap_scan == 2) {
/*
* User-initiated scan request in ap_scan == 2; scan with
* wildcard SSID.
*/
ssid = NULL;
} else {
struct wpa_ssid *start = ssid, *tssid;
int freqs_set = 0;
if (ssid == NULL && max_ssids > 1)
ssid = wpa_s->conf->ssid;
while (ssid) {
if (!ssid->disabled && ssid->scan_ssid) {
wpa_hexdump_ascii(MSG_DEBUG, "Scan SSID",
ssid->ssid, ssid->ssid_len);
params.ssids[params.num_ssids].ssid =
ssid->ssid;
params.ssids[params.num_ssids].ssid_len =
ssid->ssid_len;
params.num_ssids++;
if (params.num_ssids + 1 >= max_ssids)
break;
}
ssid = ssid->next;
if (ssid == start)
break;
if (ssid == NULL && max_ssids > 1 &&
start != wpa_s->conf->ssid)
ssid = wpa_s->conf->ssid;
}
for (tssid = wpa_s->conf->ssid; tssid; tssid = tssid->next) {
if (tssid->disabled)
continue;
if ((params.freqs || !freqs_set) && tssid->scan_freq) {
int_array_concat(&params.freqs,
tssid->scan_freq);
} else {
os_free(params.freqs);
params.freqs = NULL;
}
freqs_set = 1;
}
int_array_sort_unique(params.freqs);
}
if (ssid && max_ssids == 1) {
/*
* If the driver is limited to 1 SSID at a time interleave
* wildcard SSID scans with specific SSID scans to avoid
* waiting a long time for a wildcard scan.
*/
if (!wpa_s->prev_scan_wildcard) {
params.ssids[0].ssid = NULL;
params.ssids[0].ssid_len = 0;
wpa_s->prev_scan_wildcard = 1;
wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for "
"wildcard SSID (Interleave with specific)");
} else {
wpa_s->prev_scan_ssid = ssid;
wpa_s->prev_scan_wildcard = 0;
wpa_dbg(wpa_s, MSG_DEBUG,
"Starting AP scan for specific SSID: %s",
wpa_ssid_txt(ssid->ssid, ssid->ssid_len));
}
} else if (ssid) {
/* max_ssids > 1 */
wpa_s->prev_scan_ssid = ssid;
wpa_dbg(wpa_s, MSG_DEBUG, "Include wildcard SSID in "
"the scan request");
params.num_ssids++;
} else {
wpa_s->prev_scan_ssid = WILDCARD_SSID_SCAN;
params.num_ssids++;
wpa_dbg(wpa_s, MSG_DEBUG, "Starting AP scan for wildcard "
"SSID");
}
#ifdef CONFIG_P2P
ssid_list_set:
#endif /* CONFIG_P2P */
wpa_supplicant_optimize_freqs(wpa_s, &params);
extra_ie = wpa_supplicant_extra_ies(wpa_s, &params);
if (params.freqs == NULL && wpa_s->next_scan_freqs) {
wpa_dbg(wpa_s, MSG_DEBUG, "Optimize scan based on previously "
"generated frequency list");
params.freqs = wpa_s->next_scan_freqs;
} else
os_free(wpa_s->next_scan_freqs);
wpa_s->next_scan_freqs = NULL;
params.filter_ssids = wpa_supplicant_build_filter_ssids(
wpa_s->conf, &params.num_filter_ssids);
if (extra_ie) {
params.extra_ies = wpabuf_head(extra_ie);
params.extra_ies_len = wpabuf_len(extra_ie);
}
#ifdef CONFIG_P2P
if (wpa_s->p2p_in_provisioning ||
(wpa_s->show_group_started && wpa_s->go_params)) {
/*
* The interface may not yet be in P2P mode, so we have to
* explicitly request P2P probe to disable CCK rates.
*/
params.p2p_probe = 1;
}
#endif /* CONFIG_P2P */
ret = wpa_supplicant_trigger_scan(wpa_s, &params);
wpabuf_free(extra_ie);
os_free(params.freqs);
os_free(params.filter_ssids);
if (ret) {
wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate AP scan");
if (prev_state != wpa_s->wpa_state)
wpa_supplicant_set_state(wpa_s, prev_state);
wpa_supplicant_req_scan(wpa_s, 1, 0);
}
}
/**
* wpa_supplicant_req_scan - Schedule a scan for neighboring access points
* @wpa_s: Pointer to wpa_supplicant data
* @sec: Number of seconds after which to scan
* @usec: Number of microseconds after which to scan
*
* This function is used to schedule a scan for neighboring access points after
* the specified time.
*/
void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
{
/* If there's at least one network that should be specifically scanned
* then don't cancel the scan and reschedule. Some drivers do
* background scanning which generates frequent scan results, and that
* causes the specific SSID scan to get continually pushed back and
* never happen, which causes hidden APs to never get probe-scanned.
*/
if (eloop_is_timeout_registered(wpa_supplicant_scan, wpa_s, NULL) &&
wpa_s->conf->ap_scan == 1) {
struct wpa_ssid *ssid = wpa_s->conf->ssid;
while (ssid) {
if (!ssid->disabled && ssid->scan_ssid)
break;
ssid = ssid->next;
}
if (ssid) {
wpa_dbg(wpa_s, MSG_DEBUG, "Not rescheduling scan to "
"ensure that specific SSID scans occur");
return;
}
}
wpa_dbg(wpa_s, MSG_DEBUG, "Setting scan request: %d sec %d usec",
sec, usec);
eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
eloop_register_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL);
}
/**
* wpa_supplicant_delayed_sched_scan - Request a delayed scheduled scan
* @wpa_s: Pointer to wpa_supplicant data
* @sec: Number of seconds after which to scan
* @usec: Number of microseconds after which to scan
*
* This function is used to schedule periodic scans for neighboring
* access points after the specified time.
*/
int wpa_supplicant_delayed_sched_scan(struct wpa_supplicant *wpa_s,
int sec, int usec)
{
if (!wpa_s->sched_scan_supported)
return -1;
eloop_register_timeout(sec, usec,
wpa_supplicant_delayed_sched_scan_timeout,
wpa_s, NULL);
return 0;
}
/**
* wpa_supplicant_req_sched_scan - Start a periodic scheduled scan
* @wpa_s: Pointer to wpa_supplicant data
*
* This function is used to schedule periodic scans for neighboring
* access points repeating the scan continuously.
*/
int wpa_supplicant_req_sched_scan(struct wpa_supplicant *wpa_s)
{
struct wpa_driver_scan_params params;
enum wpa_states prev_state;
struct wpa_ssid *ssid;
struct wpabuf *wps_ie = NULL;
int ret;
unsigned int max_sched_scan_ssids;
int wildcard = 0;
int need_ssids;
if (!wpa_s->sched_scan_supported)
return -1;
if (wpa_s->max_sched_scan_ssids > WPAS_MAX_SCAN_SSIDS)
max_sched_scan_ssids = WPAS_MAX_SCAN_SSIDS;
else
max_sched_scan_ssids = wpa_s->max_sched_scan_ssids;
if (max_sched_scan_ssids < 1 || wpa_s->conf->disable_scan_offload)
return -1;
if (wpa_s->sched_scanning) {
wpa_dbg(wpa_s, MSG_DEBUG, "Already sched scanning");
return 0;
}
need_ssids = 0;
for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
if (!ssid->disabled && !ssid->scan_ssid) {
/* Use wildcard SSID to find this network */
wildcard = 1;
} else if (!ssid->disabled && ssid->ssid_len)
need_ssids++;
#ifdef CONFIG_WPS
if (!ssid->disabled && ssid->key_mgmt == WPA_KEY_MGMT_WPS) {
/*
* Normal scan is more reliable and faster for WPS
* operations and since these are for short periods of
* time, the benefit of trying to use sched_scan would
* be limited.
*/
wpa_dbg(wpa_s, MSG_DEBUG, "Use normal scan instead of "
"sched_scan for WPS");
return -1;
}
#endif /* CONFIG_WPS */
}
if (wildcard)
need_ssids++;
if (wpa_s->normal_scans < 3 &&
(need_ssids <= wpa_s->max_scan_ssids ||
wpa_s->max_scan_ssids >= (int) max_sched_scan_ssids)) {
/*
* When normal scan can speed up operations, use that for the
* first operations before starting the sched_scan to allow
* user space sleep more. We do this only if the normal scan
* has functionality that is suitable for this or if the
* sched_scan does not have better support for multiple SSIDs.
*/
wpa_dbg(wpa_s, MSG_DEBUG, "Use normal scan instead of "
"sched_scan for initial scans (normal_scans=%d)",
wpa_s->normal_scans);
return -1;
}
os_memset(&params, 0, sizeof(params));
/* If we can't allocate space for the filters, we just don't filter */
params.filter_ssids = os_zalloc(wpa_s->max_match_sets *
sizeof(struct wpa_driver_scan_filter));
prev_state = wpa_s->wpa_state;
if (wpa_s->wpa_state == WPA_DISCONNECTED ||
wpa_s->wpa_state == WPA_INACTIVE)
wpa_supplicant_set_state(wpa_s, WPA_SCANNING);
/* Find the starting point from which to continue scanning */
ssid = wpa_s->conf->ssid;
if (wpa_s->prev_sched_ssid) {
while (ssid) {
if (ssid == wpa_s->prev_sched_ssid) {
ssid = ssid->next;
break;
}
ssid = ssid->next;
}
}
if (!ssid || !wpa_s->prev_sched_ssid) {
wpa_dbg(wpa_s, MSG_DEBUG, "Beginning of SSID list");
wpa_s->sched_scan_interval = 10;
wpa_s->sched_scan_timeout = max_sched_scan_ssids * 2;
wpa_s->first_sched_scan = 1;
ssid = wpa_s->conf->ssid;
wpa_s->prev_sched_ssid = ssid;
}
if (wildcard) {
wpa_dbg(wpa_s, MSG_DEBUG, "Add wildcard SSID to sched_scan");
params.num_ssids++;
}
while (ssid) {
if (ssid->disabled)
goto next;
if (params.num_filter_ssids < wpa_s->max_match_sets &&
params.filter_ssids && ssid->ssid && ssid->ssid_len) {
wpa_dbg(wpa_s, MSG_DEBUG, "add to filter ssid: %s",
wpa_ssid_txt(ssid->ssid, ssid->ssid_len));
os_memcpy(params.filter_ssids[params.num_filter_ssids].ssid,
ssid->ssid, ssid->ssid_len);
params.filter_ssids[params.num_filter_ssids].ssid_len =
ssid->ssid_len;
params.num_filter_ssids++;
} else if (params.filter_ssids && ssid->ssid && ssid->ssid_len)
{
wpa_dbg(wpa_s, MSG_DEBUG, "Not enough room for SSID "
"filter for sched_scan - drop filter");
os_free(params.filter_ssids);
params.filter_ssids = NULL;
params.num_filter_ssids = 0;
}
if (ssid->scan_ssid && ssid->ssid && ssid->ssid_len) {
if (params.num_ssids == max_sched_scan_ssids)
break; /* only room for broadcast SSID */
wpa_dbg(wpa_s, MSG_DEBUG,
"add to active scan ssid: %s",
wpa_ssid_txt(ssid->ssid, ssid->ssid_len));
params.ssids[params.num_ssids].ssid =
ssid->ssid;
params.ssids[params.num_ssids].ssid_len =
ssid->ssid_len;
params.num_ssids++;
if (params.num_ssids >= max_sched_scan_ssids) {
wpa_s->prev_sched_ssid = ssid;
do {
ssid = ssid->next;
} while (ssid &&
(ssid->disabled || !ssid->scan_ssid));
break;
}
}
next:
wpa_s->prev_sched_ssid = ssid;
ssid = ssid->next;
}
if (params.num_filter_ssids == 0) {
os_free(params.filter_ssids);
params.filter_ssids = NULL;
}
if (wpa_s->wps)
wps_ie = wpa_supplicant_extra_ies(wpa_s, &params);
if (ssid || !wpa_s->first_sched_scan) {
wpa_dbg(wpa_s, MSG_DEBUG,
"Starting sched scan: interval %d timeout %d",
wpa_s->sched_scan_interval, wpa_s->sched_scan_timeout);
} else {
wpa_dbg(wpa_s, MSG_DEBUG,
"Starting sched scan: interval %d (no timeout)",
wpa_s->sched_scan_interval);
}
ret = wpa_supplicant_start_sched_scan(wpa_s, &params,
wpa_s->sched_scan_interval);
wpabuf_free(wps_ie);
os_free(params.filter_ssids);
if (ret) {
wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate sched scan");
if (prev_state != wpa_s->wpa_state)
wpa_supplicant_set_state(wpa_s, prev_state);
return ret;
}
/* If we have more SSIDs to scan, add a timeout so we scan them too */
if (ssid || !wpa_s->first_sched_scan) {
wpa_s->sched_scan_timed_out = 0;
eloop_register_timeout(wpa_s->sched_scan_timeout, 0,
wpa_supplicant_sched_scan_timeout,
wpa_s, NULL);
wpa_s->first_sched_scan = 0;
wpa_s->sched_scan_timeout /= 2;
wpa_s->sched_scan_interval *= 2;
}
return 0;
}
/**
* wpa_supplicant_cancel_scan - Cancel a scheduled scan request
* @wpa_s: Pointer to wpa_supplicant data
*
* This function is used to cancel a scan request scheduled with
* wpa_supplicant_req_scan().
*/
void wpa_supplicant_cancel_scan(struct wpa_supplicant *wpa_s)
{
wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling scan request");
eloop_cancel_timeout(wpa_supplicant_scan, wpa_s, NULL);
}
/**
* wpa_supplicant_cancel_sched_scan - Stop running scheduled scans
* @wpa_s: Pointer to wpa_supplicant data
*
* This function is used to stop a periodic scheduled scan.
*/
void wpa_supplicant_cancel_sched_scan(struct wpa_supplicant *wpa_s)
{
if (!wpa_s->sched_scanning)
return;
wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling sched scan");
eloop_cancel_timeout(wpa_supplicant_sched_scan_timeout, wpa_s, NULL);
wpa_supplicant_stop_sched_scan(wpa_s);
}
void wpa_supplicant_notify_scanning(struct wpa_supplicant *wpa_s,
int scanning)
{
if (wpa_s->scanning != scanning) {
wpa_s->scanning = scanning;
wpas_notify_scanning(wpa_s);
}
}
static int wpa_scan_get_max_rate(const struct wpa_scan_res *res)
{
int rate = 0;
const u8 *ie;
int i;
ie = wpa_scan_get_ie(res, WLAN_EID_SUPP_RATES);
for (i = 0; ie && i < ie[1]; i++) {
if ((ie[i + 2] & 0x7f) > rate)
rate = ie[i + 2] & 0x7f;
}
ie = wpa_scan_get_ie(res, WLAN_EID_EXT_SUPP_RATES);
for (i = 0; ie && i < ie[1]; i++) {
if ((ie[i + 2] & 0x7f) > rate)
rate = ie[i + 2] & 0x7f;
}
return rate;
}
const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie)
{
const u8 *end, *pos;
pos = (const u8 *) (res + 1);
end = pos + res->ie_len;
while (pos + 1 < end) {
if (pos + 2 + pos[1] > end)
break;
if (pos[0] == ie)
return pos;
pos += 2 + pos[1];
}
return NULL;
}
const u8 * wpa_scan_get_vendor_ie(const struct wpa_scan_res *res,
u32 vendor_type)
{
const u8 *end, *pos;
pos = (const u8 *) (res + 1);
end = pos + res->ie_len;
while (pos + 1 < end) {
if (pos + 2 + pos[1] > end)
break;
if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
vendor_type == WPA_GET_BE32(&pos[2]))
return pos;
pos += 2 + pos[1];
}
return NULL;
}
struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
u32 vendor_type)
{
struct wpabuf *buf;
const u8 *end, *pos;
buf = wpabuf_alloc(res->ie_len);
if (buf == NULL)
return NULL;
pos = (const u8 *) (res + 1);
end = pos + res->ie_len;
while (pos + 1 < end) {
if (pos + 2 + pos[1] > end)
break;
if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
vendor_type == WPA_GET_BE32(&pos[2]))
wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
pos += 2 + pos[1];
}
if (wpabuf_len(buf) == 0) {
wpabuf_free(buf);
buf = NULL;
}
return buf;
}
struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
const struct wpa_scan_res *res, u32 vendor_type)
{
struct wpabuf *buf;
const u8 *end, *pos;
if (res->beacon_ie_len == 0)
return NULL;
buf = wpabuf_alloc(res->beacon_ie_len);
if (buf == NULL)
return NULL;
pos = (const u8 *) (res + 1);
pos += res->ie_len;
end = pos + res->beacon_ie_len;
while (pos + 1 < end) {
if (pos + 2 + pos[1] > end)
break;
if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
vendor_type == WPA_GET_BE32(&pos[2]))
wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
pos += 2 + pos[1];
}
if (wpabuf_len(buf) == 0) {
wpabuf_free(buf);
buf = NULL;
}
return buf;
}
/*
* Channels with a great SNR can operate at full rate. What is a great SNR?
* This doc https://supportforums.cisco.com/docs/DOC-12954 says, "the general
* rule of thumb is that any SNR above 20 is good." This one
* http://www.cisco.com/en/US/tech/tk722/tk809/technologies_q_and_a_item09186a00805e9a96.shtml#qa23
* recommends 25 as a minimum SNR for 54 Mbps data rate. 30 is chosen here as a
* conservative value.
*/
#define GREAT_SNR 30
/* Compare function for sorting scan results. Return >0 if @b is considered
* better. */
static int wpa_scan_result_compar(const void *a, const void *b)
{
#define IS_5GHZ(n) (n > 4000)
#define MIN(a,b) a < b ? a : b
struct wpa_scan_res **_wa = (void *) a;
struct wpa_scan_res **_wb = (void *) b;
struct wpa_scan_res *wa = *_wa;
struct wpa_scan_res *wb = *_wb;
int wpa_a, wpa_b, maxrate_a, maxrate_b;
int snr_a, snr_b;
/* WPA/WPA2 support preferred */
wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
wpa_scan_get_ie(wa, WLAN_EID_RSN) != NULL;
wpa_b = wpa_scan_get_vendor_ie(wb, WPA_IE_VENDOR_TYPE) != NULL ||
wpa_scan_get_ie(wb, WLAN_EID_RSN) != NULL;
if (wpa_b && !wpa_a)
return 1;
if (!wpa_b && wpa_a)
return -1;
/* privacy support preferred */
if ((wa->caps & IEEE80211_CAP_PRIVACY) == 0 &&
(wb->caps & IEEE80211_CAP_PRIVACY))
return 1;
if ((wa->caps & IEEE80211_CAP_PRIVACY) &&
(wb->caps & IEEE80211_CAP_PRIVACY) == 0)
return -1;
if ((wa->flags & wb->flags & WPA_SCAN_LEVEL_DBM) &&
!((wa->flags | wb->flags) & WPA_SCAN_NOISE_INVALID)) {
snr_a = MIN(wa->level - wa->noise, GREAT_SNR);
snr_b = MIN(wb->level - wb->noise, GREAT_SNR);
} else {
/* Not suitable information to calculate SNR, so use level */
snr_a = wa->level;
snr_b = wb->level;
}
/* best/max rate preferred if SNR close enough */
if ((snr_a && snr_b && abs(snr_b - snr_a) < 5) ||
(wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
maxrate_a = wpa_scan_get_max_rate(wa);
maxrate_b = wpa_scan_get_max_rate(wb);
if (maxrate_a != maxrate_b)
return maxrate_b - maxrate_a;
if (IS_5GHZ(wa->freq) ^ IS_5GHZ(wb->freq))
return IS_5GHZ(wa->freq) ? -1 : 1;
}
/* use freq for channel preference */
/* all things being equal, use SNR; if SNRs are
* identical, use quality values since some drivers may only report
* that value and leave the signal level zero */
if (snr_b == snr_a)
return wb->qual - wa->qual;
return snr_b - snr_a;
#undef MIN
#undef IS_5GHZ
}
#ifdef CONFIG_WPS
/* Compare function for sorting scan results when searching a WPS AP for
* provisioning. Return >0 if @b is considered better. */
static int wpa_scan_result_wps_compar(const void *a, const void *b)
{
struct wpa_scan_res **_wa = (void *) a;
struct wpa_scan_res **_wb = (void *) b;
struct wpa_scan_res *wa = *_wa;
struct wpa_scan_res *wb = *_wb;
int uses_wps_a, uses_wps_b;
struct wpabuf *wps_a, *wps_b;
int res;
/* Optimization - check WPS IE existence before allocated memory and
* doing full reassembly. */
uses_wps_a = wpa_scan_get_vendor_ie(wa, WPS_IE_VENDOR_TYPE) != NULL;
uses_wps_b = wpa_scan_get_vendor_ie(wb, WPS_IE_VENDOR_TYPE) != NULL;
if (uses_wps_a && !uses_wps_b)
return -1;
if (!uses_wps_a && uses_wps_b)
return 1;
if (uses_wps_a && uses_wps_b) {
wps_a = wpa_scan_get_vendor_ie_multi(wa, WPS_IE_VENDOR_TYPE);
wps_b = wpa_scan_get_vendor_ie_multi(wb, WPS_IE_VENDOR_TYPE);
res = wps_ap_priority_compar(wps_a, wps_b);
wpabuf_free(wps_a);
wpabuf_free(wps_b);
if (res)
return res;
}
/*
* Do not use current AP security policy as a sorting criteria during
* WPS provisioning step since the AP may get reconfigured at the
* completion of provisioning.
*/
/* all things being equal, use signal level; if signal levels are
* identical, use quality values since some drivers may only report
* that value and leave the signal level zero */
if (wb->level == wa->level)
return wb->qual - wa->qual;
return wb->level - wa->level;
}
#endif /* CONFIG_WPS */
static void dump_scan_res(struct wpa_scan_results *scan_res)
{
#ifndef CONFIG_NO_STDOUT_DEBUG
size_t i;
if (scan_res->res == NULL || scan_res->num == 0)
return;
wpa_printf(MSG_EXCESSIVE, "Sorted scan results");
for (i = 0; i < scan_res->num; i++) {
struct wpa_scan_res *r = scan_res->res[i];
if ((r->flags & (WPA_SCAN_LEVEL_DBM | WPA_SCAN_NOISE_INVALID))
== WPA_SCAN_LEVEL_DBM) {
int snr = r->level - r->noise;
wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
"noise=%d level=%d snr=%d%s flags=0x%x",
MAC2STR(r->bssid), r->freq, r->qual,
r->noise, r->level, snr,
snr >= GREAT_SNR ? "*" : "", r->flags);
} else {
wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
"noise=%d level=%d flags=0x%x",
MAC2STR(r->bssid), r->freq, r->qual,
r->noise, r->level, r->flags);
}
}
#endif /* CONFIG_NO_STDOUT_DEBUG */
}
int wpa_supplicant_filter_bssid_match(struct wpa_supplicant *wpa_s,
const u8 *bssid)
{
size_t i;
if (wpa_s->bssid_filter == NULL)
return 1;
for (i = 0; i < wpa_s->bssid_filter_count; i++) {
if (os_memcmp(wpa_s->bssid_filter + i * ETH_ALEN, bssid,
ETH_ALEN) == 0)
return 1;
}
return 0;
}
static void filter_scan_res(struct wpa_supplicant *wpa_s,
struct wpa_scan_results *res)
{
size_t i, j;
if (wpa_s->bssid_filter == NULL)
return;
for (i = 0, j = 0; i < res->num; i++) {
if (wpa_supplicant_filter_bssid_match(wpa_s,
res->res[i]->bssid)) {
res->res[j++] = res->res[i];
} else {
os_free(res->res[i]);
res->res[i] = NULL;
}
}
if (res->num != j) {
wpa_printf(MSG_DEBUG, "Filtered out %d scan results",
(int) (res->num - j));
res->num = j;
}
}
/**
* wpa_supplicant_get_scan_results - Get scan results
* @wpa_s: Pointer to wpa_supplicant data
* @info: Information about what was scanned or %NULL if not available
* @new_scan: Whether a new scan was performed
* Returns: Scan results, %NULL on failure
*
* This function request the current scan results from the driver and updates
* the local BSS list wpa_s->bss. The caller is responsible for freeing the
* results with wpa_scan_results_free().
*/
struct wpa_scan_results *
wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
struct scan_info *info, int new_scan)
{
struct wpa_scan_results *scan_res;
size_t i;
int (*compar)(const void *, const void *) = wpa_scan_result_compar;
scan_res = wpa_drv_get_scan_results2(wpa_s);
if (scan_res == NULL) {
wpa_dbg(wpa_s, MSG_DEBUG, "Failed to get scan results");
return NULL;
}
filter_scan_res(wpa_s, scan_res);
#ifdef CONFIG_WPS
if (wpas_wps_in_progress(wpa_s)) {
wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Order scan results with WPS "
"provisioning rules");
compar = wpa_scan_result_wps_compar;
}
#endif /* CONFIG_WPS */
qsort(scan_res->res, scan_res->num, sizeof(struct wpa_scan_res *),
compar);
dump_scan_res(scan_res);
wpa_bss_update_start(wpa_s);
for (i = 0; i < scan_res->num; i++)
wpa_bss_update_scan_res(wpa_s, scan_res->res[i]);
wpa_bss_update_end(wpa_s, info, new_scan);
return scan_res;
}
int wpa_supplicant_update_scan_results(struct wpa_supplicant *wpa_s)
{
struct wpa_scan_results *scan_res;
scan_res = wpa_supplicant_get_scan_results(wpa_s, NULL, 0);
if (scan_res == NULL)
return -1;
wpa_scan_results_free(scan_res);
return 0;
}
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