wpa_supplicant/bgscan_learn.c - LeafOS-Project/android_external_wpa_supplicant_8 - Gitiles

 /*
  * WPA Supplicant - background scan and roaming module: learn
  * Copyright (c) 2009-2010, Jouni Malinen <j@w1.fi>
  *
  * This software may be distributed under the terms of the BSD license.
  * See README for more details.
  */

 #include "includes.h"

 #include "common.h"
 #include "eloop.h"
 #include "list.h"
 #include "common/ieee802_11_defs.h"
 #include "drivers/driver.h"
 #include "config_ssid.h"
 #include "wpa_supplicant_i.h"
 #include "driver_i.h"
 #include "scan.h"
 #include "bgscan.h"

 struct bgscan_learn_bss {
 	struct dl_list list;
 	u8 bssid[ETH_ALEN];
 	int freq;
 	u8 *neigh; /* num_neigh * ETH_ALEN buffer */
 	size_t num_neigh;
 };

 struct bgscan_learn_data {
 	struct wpa_supplicant *wpa_s;
 	const struct wpa_ssid *ssid;
 	int scan_interval;
 	int signal_threshold;
 	int short_interval; /* use if signal < threshold */
 	int long_interval; /* use if signal > threshold */
 	struct os_reltime last_bgscan;
 	char *fname;
 	struct dl_list bss;
 	int *supp_freqs;
 	int probe_idx;
 };


 static void bss_free(struct bgscan_learn_bss *bss)
 {
 	os_free(bss->neigh);
 	os_free(bss);
 }


 static int bssid_in_array(u8 *array, size_t array_len, const u8 *bssid)
 {
 	size_t i;

 	if (array == NULL || array_len == 0)
 		return 0;

 	for (i = 0; i < array_len; i++) {
 		if (os_memcmp(array + i * ETH_ALEN, bssid, ETH_ALEN) == 0)
 			return 1;
 	}

 	return 0;
 }


 static void bgscan_learn_add_neighbor(struct bgscan_learn_bss *bss,
 				      const u8 *bssid)
 {
 	u8 *n;

 	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
 		return;
 	if (bssid_in_array(bss->neigh, bss->num_neigh, bssid))
 		return;

 	n = os_realloc_array(bss->neigh, bss->num_neigh + 1, ETH_ALEN);
 	if (n == NULL)
 		return;

 	os_memcpy(n + bss->num_neigh * ETH_ALEN, bssid, ETH_ALEN);
 	bss->neigh = n;
 	bss->num_neigh++;
 }


 static struct bgscan_learn_bss * bgscan_learn_get_bss(
 	struct bgscan_learn_data *data, const u8 *bssid)
 {
 	struct bgscan_learn_bss *bss;

 	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
 		if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
 			return bss;
 	}
 	return NULL;
 }


 static int bgscan_learn_load(struct bgscan_learn_data *data)
 {
 	FILE *f;
 	char buf[128];
 	struct bgscan_learn_bss *bss;

 	if (data->fname == NULL)
 		return 0;

 	f = fopen(data->fname, "r");
 	if (f == NULL)
 		return 0;

 	wpa_printf(MSG_DEBUG, "bgscan learn: Loading data from %s",
 		   data->fname);

 	if (fgets(buf, sizeof(buf), f) == NULL ||
 	    os_strncmp(buf, "wpa_supplicant-bgscan-learn\n", 28) != 0) {
 		wpa_printf(MSG_INFO, "bgscan learn: Invalid data file %s",
 			   data->fname);
 		fclose(f);
 		return -1;
 	}

 	while (fgets(buf, sizeof(buf), f)) {
 		if (os_strncmp(buf, "BSS ", 4) == 0) {
 			bss = os_zalloc(sizeof(*bss));
 			if (!bss)
 				continue;
 			if (hwaddr_aton(buf + 4, bss->bssid) < 0) {
 				bss_free(bss);
 				continue;
 			}
 			bss->freq = atoi(buf + 4 + 18);
 			dl_list_add(&data->bss, &bss->list);
 			wpa_printf(MSG_DEBUG, "bgscan learn: Loaded BSS "
 				   "entry: " MACSTR " freq=%d",
 				   MAC2STR(bss->bssid), bss->freq);
 		}

 		if (os_strncmp(buf, "NEIGHBOR ", 9) == 0) {
 			u8 addr[ETH_ALEN];

 			if (hwaddr_aton(buf + 9, addr) < 0)
 				continue;
 			bss = bgscan_learn_get_bss(data, addr);
 			if (bss == NULL)
 				continue;
 			if (hwaddr_aton(buf + 9 + 18, addr) < 0)
 				continue;

 			bgscan_learn_add_neighbor(bss, addr);
 		}
 	}

 	fclose(f);
 	return 0;
 }


 static void bgscan_learn_save(struct bgscan_learn_data *data)
 {
 	FILE *f;
 	struct bgscan_learn_bss *bss;

 	if (data->fname == NULL)
 		return;

 	wpa_printf(MSG_DEBUG, "bgscan learn: Saving data to %s",
 		   data->fname);

 	f = fopen(data->fname, "w");
 	if (f == NULL)
 		return;
 	fprintf(f, "wpa_supplicant-bgscan-learn\n");

 	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
 		fprintf(f, "BSS " MACSTR " %d\n",
 			MAC2STR(bss->bssid), bss->freq);
 	}

 	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
 		size_t i;
 		for (i = 0; i < bss->num_neigh; i++) {
 			fprintf(f, "NEIGHBOR " MACSTR " " MACSTR "\n",
 				MAC2STR(bss->bssid),
 				MAC2STR(bss->neigh + i * ETH_ALEN));
 		}
 	}

 	fclose(f);
 }


 static int in_array(int *array, int val)
 {
 	int i;

 	if (array == NULL)
 		return 0;

 	for (i = 0; array[i]; i++) {
 		if (array[i] == val)
 			return 1;
 	}

 	return 0;
 }


 static int * bgscan_learn_get_freqs(struct bgscan_learn_data *data,
 				    size_t *count)
 {
 	struct bgscan_learn_bss *bss;
 	int *freqs = NULL, *n;

 	*count = 0;

 	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
 		if (in_array(freqs, bss->freq))
 			continue;
 		n = os_realloc_array(freqs, *count + 2, sizeof(int));
 		if (n == NULL)
 			return freqs;
 		freqs = n;
 		freqs[*count] = bss->freq;
 		(*count)++;
 		freqs[*count] = 0;
 	}

 	return freqs;
 }


 static int * bgscan_learn_get_probe_freq(struct bgscan_learn_data *data,
 					 int *freqs, size_t count)
 {
 	int idx, *n;

 	if (data->supp_freqs == NULL)
 		return freqs;

 	idx = data->probe_idx;
 	do {
 		if (!in_array(freqs, data->supp_freqs[idx])) {
 			wpa_printf(MSG_DEBUG, "bgscan learn: Probe new freq "
 				   "%u", data->supp_freqs[idx]);
 			data->probe_idx = idx + 1;
 			if (data->supp_freqs[data->probe_idx] == 0)
 				data->probe_idx = 0;
 			n = os_realloc_array(freqs, count + 2, sizeof(int));
 			if (n == NULL)
 				return freqs;
 			freqs = n;
 			freqs[count] = data->supp_freqs[idx];
 			count++;
 			freqs[count] = 0;
 			break;
 		}

 		idx++;
 		if (data->supp_freqs[idx] == 0)
 			idx = 0;
 	} while (idx != data->probe_idx);

 	return freqs;
 }


 static void bgscan_learn_timeout(void *eloop_ctx, void *timeout_ctx)
 {
 	struct bgscan_learn_data *data = eloop_ctx;
 	struct wpa_supplicant *wpa_s = data->wpa_s;
 	struct wpa_driver_scan_params params;
 	int *freqs = NULL;
 	size_t count, i;
 	char msg[100], *pos;

 	os_memset(&params, 0, sizeof(params));
 	params.num_ssids = 1;
 	params.ssids[0].ssid = data->ssid->ssid;
 	params.ssids[0].ssid_len = data->ssid->ssid_len;
 	if (data->ssid->scan_freq)
 		params.freqs = data->ssid->scan_freq;
 	else {
 		freqs = bgscan_learn_get_freqs(data, &count);
 		wpa_printf(MSG_DEBUG, "bgscan learn: BSSes in this ESS have "
 			   "been seen on %u channels", (unsigned int) count);
 		freqs = bgscan_learn_get_probe_freq(data, freqs, count);

 		msg[0] = '\0';
 		pos = msg;
 		for (i = 0; freqs && freqs[i]; i++) {
 			int ret;
 			ret = os_snprintf(pos, msg + sizeof(msg) - pos, " %d",
 					  freqs[i]);
 			if (os_snprintf_error(msg + sizeof(msg) - pos, ret))
 				break;
 			pos += ret;
 		}
 		pos[0] = '\0';
 		wpa_printf(MSG_DEBUG, "bgscan learn: Scanning frequencies:%s",
 			   msg);
 		params.freqs = freqs;
 	}

 	wpa_printf(MSG_DEBUG, "bgscan learn: Request a background scan");
 	if (wpa_supplicant_trigger_scan(wpa_s, &params, true, false)) {
 		wpa_printf(MSG_DEBUG, "bgscan learn: Failed to trigger scan");
 		eloop_register_timeout(data->scan_interval, 0,
 				       bgscan_learn_timeout, data, NULL);
 	} else
 		os_get_reltime(&data->last_bgscan);
 	os_free(freqs);
 }


 static int bgscan_learn_get_params(struct bgscan_learn_data *data,
 				   const char *params)
 {
 	const char *pos;

 	data->short_interval = atoi(params);

 	pos = os_strchr(params, ':');
 	if (pos == NULL)
 		return 0;
 	pos++;
 	data->signal_threshold = atoi(pos);
 	pos = os_strchr(pos, ':');
 	if (pos == NULL) {
 		wpa_printf(MSG_ERROR, "bgscan learn: Missing scan interval "
 			   "for high signal");
 		return -1;
 	}
 	pos++;
 	data->long_interval = atoi(pos);
 	pos = os_strchr(pos, ':');
 	if (pos) {
 		pos++;
 		data->fname = os_strdup(pos);
 	}

 	return 0;
 }


 static int * bgscan_learn_get_supp_freqs(struct wpa_supplicant *wpa_s)
 {
 	struct hostapd_hw_modes *modes;
 	int i, j, *freqs = NULL, *n;
 	size_t count = 0;

 	modes = wpa_s->hw.modes;
 	if (modes == NULL)
 		return NULL;

 	for (i = 0; i < wpa_s->hw.num_modes; i++) {
 		for (j = 0; j < modes[i].num_channels; j++) {
 			if (modes[i].channels[j].flag & HOSTAPD_CHAN_DISABLED)
 				continue;
 			/* some hw modes (e.g. 11b & 11g) contain same freqs */
 			if (in_array(freqs, modes[i].channels[j].freq))
 				continue;
 			n = os_realloc_array(freqs, count + 2, sizeof(int));
 			if (n == NULL)
 				continue;

 			freqs = n;
 			freqs[count] = modes[i].channels[j].freq;
 			count++;
 			freqs[count] = 0;
 		}
 	}

 	return freqs;
 }


 static void * bgscan_learn_init(struct wpa_supplicant *wpa_s,
 				const char *params,
 				const struct wpa_ssid *ssid)
 {
 	struct bgscan_learn_data *data;

 	data = os_zalloc(sizeof(*data));
 	if (data == NULL)
 		return NULL;
 	dl_list_init(&data->bss);
 	data->wpa_s = wpa_s;
 	data->ssid = ssid;
 	if (bgscan_learn_get_params(data, params) < 0) {
 		os_free(data->fname);
 		os_free(data);
 		return NULL;
 	}
 	if (data->short_interval <= 0)
 		data->short_interval = 30;
 	if (data->long_interval <= 0)
 		data->long_interval = 30;

 	if (bgscan_learn_load(data) < 0) {
 		os_free(data->fname);
 		os_free(data);
 		return NULL;
 	}

 	wpa_printf(MSG_DEBUG, "bgscan learn: Signal strength threshold %d  "
 		   "Short bgscan interval %d  Long bgscan interval %d",
 		   data->signal_threshold, data->short_interval,
 		   data->long_interval);

 	if (data->signal_threshold &&
 	    wpa_drv_signal_monitor(wpa_s, data->signal_threshold, 4) < 0) {
 		wpa_printf(MSG_ERROR, "bgscan learn: Failed to enable "
 			   "signal strength monitoring");
 	}

 	data->supp_freqs = bgscan_learn_get_supp_freqs(wpa_s);
 	data->scan_interval = data->short_interval;
 	if (data->signal_threshold) {
 		/* Poll for signal info to set initial scan interval */
 		struct wpa_signal_info siginfo;
 		if (wpa_drv_signal_poll(wpa_s, &siginfo) == 0 &&
 		    siginfo.data.signal >= data->signal_threshold)
 			data->scan_interval = data->long_interval;
 	}

 	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
 			       data, NULL);

 	/*
 	 * This function is called immediately after an association, so it is
 	 * reasonable to assume that a scan was completed recently. This makes
 	 * us skip an immediate new scan in cases where the current signal
 	 * level is below the bgscan threshold.
 	 */
 	os_get_reltime(&data->last_bgscan);

 	return data;
 }


 static void bgscan_learn_deinit(void *priv)
 {
 	struct bgscan_learn_data *data = priv;
 	struct bgscan_learn_bss *bss, *n;

 	bgscan_learn_save(data);
 	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
 	if (data->signal_threshold)
 		wpa_drv_signal_monitor(data->wpa_s, 0, 0);
 	os_free(data->fname);
 	dl_list_for_each_safe(bss, n, &data->bss, struct bgscan_learn_bss,
 			      list) {
 		dl_list_del(&bss->list);
 		bss_free(bss);
 	}
 	os_free(data->supp_freqs);
 	os_free(data);
 }


 static int bgscan_learn_bss_match(struct bgscan_learn_data *data,
 				  struct wpa_scan_res *bss)
 {
 	const u8 *ie;

 	ie = wpa_scan_get_ie(bss, WLAN_EID_SSID);
 	if (ie == NULL)
 		return 0;

 	if (data->ssid->ssid_len != ie[1] ||
 	    os_memcmp(data->ssid->ssid, ie + 2, ie[1]) != 0)
 		return 0; /* SSID mismatch */

 	return 1;
 }


 static int bgscan_learn_notify_scan(void *priv,
 				    struct wpa_scan_results *scan_res)
 {
 	struct bgscan_learn_data *data = priv;
 	size_t i, j;
 #define MAX_BSS 50
 	u8 bssid[MAX_BSS * ETH_ALEN];
 	size_t num_bssid = 0;

 	wpa_printf(MSG_DEBUG, "bgscan learn: scan result notification");

 	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
 	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
 			       data, NULL);

 	for (i = 0; i < scan_res->num; i++) {
 		struct wpa_scan_res *res = scan_res->res[i];
 		if (!bgscan_learn_bss_match(data, res))
 			continue;

 		if (num_bssid < MAX_BSS) {
 			os_memcpy(bssid + num_bssid * ETH_ALEN, res->bssid,
 				  ETH_ALEN);
 			num_bssid++;
 		}
 	}
 	wpa_printf(MSG_DEBUG, "bgscan learn: %u matching BSSes in scan "
 		   "results", (unsigned int) num_bssid);

 	for (i = 0; i < scan_res->num; i++) {
 		struct wpa_scan_res *res = scan_res->res[i];
 		struct bgscan_learn_bss *bss;

 		if (!bgscan_learn_bss_match(data, res))
 			continue;

 		bss = bgscan_learn_get_bss(data, res->bssid);
 		if (bss && bss->freq != res->freq) {
 			wpa_printf(MSG_DEBUG, "bgscan learn: Update BSS "
 			   MACSTR " freq %d -> %d",
 				   MAC2STR(res->bssid), bss->freq, res->freq);
 			bss->freq = res->freq;
 		} else if (!bss) {
 			wpa_printf(MSG_DEBUG, "bgscan learn: Add BSS " MACSTR
 				   " freq=%d", MAC2STR(res->bssid), res->freq);
 			bss = os_zalloc(sizeof(*bss));
 			if (!bss)
 				continue;
 			os_memcpy(bss->bssid, res->bssid, ETH_ALEN);
 			bss->freq = res->freq;
 			dl_list_add(&data->bss, &bss->list);
 		}

 		for (j = 0; j < num_bssid; j++) {
 			u8 *addr = bssid + j * ETH_ALEN;
 			bgscan_learn_add_neighbor(bss, addr);
 		}
 	}

 	/*
 	 * A more advanced bgscan could process scan results internally, select
 	 * the BSS and request roam if needed. This sample uses the existing
 	 * BSS/ESS selection routine. Change this to return 1 if selection is
 	 * done inside the bgscan module.
 	 */

 	return 0;
 }


 static void bgscan_learn_notify_beacon_loss(void *priv)
 {
 	wpa_printf(MSG_DEBUG, "bgscan learn: beacon loss");
 	/* TODO: speed up background scanning */
 }


 static void bgscan_learn_notify_signal_change(void *priv, int above,
 					      int current_signal,
 					      int current_noise,
 					      int current_txrate)
 {
 	struct bgscan_learn_data *data = priv;
 	int scan = 0;
 	struct os_reltime now;

 	if (data->short_interval == data->long_interval ||
 	    data->signal_threshold == 0)
 		return;

 	wpa_printf(MSG_DEBUG, "bgscan learn: signal level changed "
 		   "(above=%d current_signal=%d current_noise=%d "
 		   "current_txrate=%d)", above, current_signal,
 		   current_noise, current_txrate);
 	if (data->scan_interval == data->long_interval && !above) {
 		wpa_printf(MSG_DEBUG, "bgscan learn: Start using short bgscan "
 			   "interval");
 		data->scan_interval = data->short_interval;
 		os_get_reltime(&now);
 		if (now.sec > data->last_bgscan.sec + 1)
 			scan = 1;
 	} else if (data->scan_interval == data->short_interval && above) {
 		wpa_printf(MSG_DEBUG, "bgscan learn: Start using long bgscan "
 			   "interval");
 		data->scan_interval = data->long_interval;
 		eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
 		eloop_register_timeout(data->scan_interval, 0,
 				       bgscan_learn_timeout, data, NULL);
 	} else if (!above) {
 		/*
 		 * Signal dropped further 4 dB. Request a new scan if we have
 		 * not yet scanned in a while.
 		 */
 		os_get_reltime(&now);
 		if (now.sec > data->last_bgscan.sec + 10)
 			scan = 1;
 	}

 	if (scan) {
 		wpa_printf(MSG_DEBUG, "bgscan learn: Trigger immediate scan");
 		eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
 		eloop_register_timeout(0, 0, bgscan_learn_timeout, data, NULL);
 	}
 }


 const struct bgscan_ops bgscan_learn_ops = {
 	.name = "learn",
 	.init = bgscan_learn_init,
 	.deinit = bgscan_learn_deinit,
 	.notify_scan = bgscan_learn_notify_scan,
 	.notify_beacon_loss = bgscan_learn_notify_beacon_loss,
 	.notify_signal_change = bgscan_learn_notify_signal_change,
 };
	/*
	* WPA Supplicant - background scan and roaming module: learn
	* Copyright (c) 2009-2010, Jouni Malinen <j@w1.fi>
	*
	* This software may be distributed under the terms of the BSD license.
	* See README for more details.
	*/

	#include "includes.h"

	#include "common.h"
	#include "eloop.h"
	#include "list.h"
	#include "common/ieee802_11_defs.h"
	#include "drivers/driver.h"
	#include "config_ssid.h"
	#include "wpa_supplicant_i.h"
	#include "driver_i.h"
	#include "scan.h"
	#include "bgscan.h"

	struct bgscan_learn_bss {
	struct dl_list list;
	u8 bssid[ETH_ALEN];
	int freq;
	u8 neigh; / num_neigh * ETH_ALEN buffer */
	size_t num_neigh;
	};

	struct bgscan_learn_data {
	struct wpa_supplicant *wpa_s;
	const struct wpa_ssid *ssid;
	int scan_interval;
	int signal_threshold;
	int short_interval; /* use if signal < threshold */
	int long_interval; /* use if signal > threshold */
	struct os_reltime last_bgscan;
	char *fname;
	struct dl_list bss;
	int *supp_freqs;
	int probe_idx;
	};


	static void bss_free(struct bgscan_learn_bss *bss)
	{
	os_free(bss->neigh);
	os_free(bss);
	}


	static int bssid_in_array(u8 array, size_t array_len, const u8 bssid)
	{
	size_t i;

	if (array == NULL \|\| array_len == 0)
	return 0;

	for (i = 0; i < array_len; i++) {
	if (os_memcmp(array + i * ETH_ALEN, bssid, ETH_ALEN) == 0)
	return 1;
	}

	return 0;
	}


	static void bgscan_learn_add_neighbor(struct bgscan_learn_bss *bss,
	const u8 *bssid)
	{
	u8 *n;

	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
	return;
	if (bssid_in_array(bss->neigh, bss->num_neigh, bssid))
	return;

	n = os_realloc_array(bss->neigh, bss->num_neigh + 1, ETH_ALEN);
	if (n == NULL)
	return;

	os_memcpy(n + bss->num_neigh * ETH_ALEN, bssid, ETH_ALEN);
	bss->neigh = n;
	bss->num_neigh++;
	}


	static struct bgscan_learn_bss * bgscan_learn_get_bss(
	struct bgscan_learn_data data, const u8 bssid)
	{
	struct bgscan_learn_bss *bss;

	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
	return bss;
	}
	return NULL;
	}


	static int bgscan_learn_load(struct bgscan_learn_data *data)
	{
	FILE *f;
	char buf[128];
	struct bgscan_learn_bss *bss;

	if (data->fname == NULL)
	return 0;

	f = fopen(data->fname, "r");
	if (f == NULL)
	return 0;

	wpa_printf(MSG_DEBUG, "bgscan learn: Loading data from %s",
	data->fname);

	if (fgets(buf, sizeof(buf), f) == NULL \|\|
	os_strncmp(buf, "wpa_supplicant-bgscan-learn\n", 28) != 0) {
	wpa_printf(MSG_INFO, "bgscan learn: Invalid data file %s",
	data->fname);
	fclose(f);
	return -1;
	}

	while (fgets(buf, sizeof(buf), f)) {
	if (os_strncmp(buf, "BSS ", 4) == 0) {
	bss = os_zalloc(sizeof(*bss));
	if (!bss)
	continue;
	if (hwaddr_aton(buf + 4, bss->bssid) < 0) {
	bss_free(bss);
	continue;
	}
	bss->freq = atoi(buf + 4 + 18);
	dl_list_add(&data->bss, &bss->list);
	wpa_printf(MSG_DEBUG, "bgscan learn: Loaded BSS "
	"entry: " MACSTR " freq=%d",
	MAC2STR(bss->bssid), bss->freq);
	}

	if (os_strncmp(buf, "NEIGHBOR ", 9) == 0) {
	u8 addr[ETH_ALEN];

	if (hwaddr_aton(buf + 9, addr) < 0)
	continue;
	bss = bgscan_learn_get_bss(data, addr);
	if (bss == NULL)
	continue;
	if (hwaddr_aton(buf + 9 + 18, addr) < 0)
	continue;

	bgscan_learn_add_neighbor(bss, addr);
	}
	}

	fclose(f);
	return 0;
	}


	static void bgscan_learn_save(struct bgscan_learn_data *data)
	{
	FILE *f;
	struct bgscan_learn_bss *bss;

	if (data->fname == NULL)
	return;

	wpa_printf(MSG_DEBUG, "bgscan learn: Saving data to %s",
	data->fname);

	f = fopen(data->fname, "w");
	if (f == NULL)
	return;
	fprintf(f, "wpa_supplicant-bgscan-learn\n");

	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	fprintf(f, "BSS " MACSTR " %d\n",
	MAC2STR(bss->bssid), bss->freq);
	}

	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	size_t i;
	for (i = 0; i < bss->num_neigh; i++) {
	fprintf(f, "NEIGHBOR " MACSTR " " MACSTR "\n",
	MAC2STR(bss->bssid),
	MAC2STR(bss->neigh + i * ETH_ALEN));
	}
	}

	fclose(f);
	}


	static int in_array(int *array, int val)
	{
	int i;

	if (array == NULL)
	return 0;

	for (i = 0; array[i]; i++) {
	if (array[i] == val)
	return 1;
	}

	return 0;
	}


	static int * bgscan_learn_get_freqs(struct bgscan_learn_data *data,
	size_t *count)
	{
	struct bgscan_learn_bss *bss;
	int freqs = NULL, n;

	*count = 0;

	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	if (in_array(freqs, bss->freq))
	continue;
	n = os_realloc_array(freqs, *count + 2, sizeof(int));
	if (n == NULL)
	return freqs;
	freqs = n;
	freqs[*count] = bss->freq;
	(*count)++;
	freqs[*count] = 0;
	}

	return freqs;
	}


	static int * bgscan_learn_get_probe_freq(struct bgscan_learn_data *data,
	int *freqs, size_t count)
	{
	int idx, *n;

	if (data->supp_freqs == NULL)
	return freqs;

	idx = data->probe_idx;
	do {
	if (!in_array(freqs, data->supp_freqs[idx])) {
	wpa_printf(MSG_DEBUG, "bgscan learn: Probe new freq "
	"%u", data->supp_freqs[idx]);
	data->probe_idx = idx + 1;
	if (data->supp_freqs[data->probe_idx] == 0)
	data->probe_idx = 0;
	n = os_realloc_array(freqs, count + 2, sizeof(int));
	if (n == NULL)
	return freqs;
	freqs = n;
	freqs[count] = data->supp_freqs[idx];
	count++;
	freqs[count] = 0;
	break;
	}

	idx++;
	if (data->supp_freqs[idx] == 0)
	idx = 0;
	} while (idx != data->probe_idx);

	return freqs;
	}


	static void bgscan_learn_timeout(void eloop_ctx, void timeout_ctx)
	{
	struct bgscan_learn_data *data = eloop_ctx;
	struct wpa_supplicant *wpa_s = data->wpa_s;
	struct wpa_driver_scan_params params;
	int *freqs = NULL;
	size_t count, i;
	char msg[100], *pos;

	os_memset(&params, 0, sizeof(params));
	params.num_ssids = 1;
	params.ssids[0].ssid = data->ssid->ssid;
	params.ssids[0].ssid_len = data->ssid->ssid_len;
	if (data->ssid->scan_freq)
	params.freqs = data->ssid->scan_freq;
	else {
	freqs = bgscan_learn_get_freqs(data, &count);
	wpa_printf(MSG_DEBUG, "bgscan learn: BSSes in this ESS have "
	"been seen on %u channels", (unsigned int) count);
	freqs = bgscan_learn_get_probe_freq(data, freqs, count);

	msg[0] = '\0';
	pos = msg;
	for (i = 0; freqs && freqs[i]; i++) {
	int ret;
	ret = os_snprintf(pos, msg + sizeof(msg) - pos, " %d",
	freqs[i]);
	if (os_snprintf_error(msg + sizeof(msg) - pos, ret))
	break;
	pos += ret;
	}
	pos[0] = '\0';
	wpa_printf(MSG_DEBUG, "bgscan learn: Scanning frequencies:%s",
	msg);
	params.freqs = freqs;
	}

	wpa_printf(MSG_DEBUG, "bgscan learn: Request a background scan");
	if (wpa_supplicant_trigger_scan(wpa_s, &params, true, false)) {
	wpa_printf(MSG_DEBUG, "bgscan learn: Failed to trigger scan");
	eloop_register_timeout(data->scan_interval, 0,
	bgscan_learn_timeout, data, NULL);
	} else
	os_get_reltime(&data->last_bgscan);
	os_free(freqs);
	}


	static int bgscan_learn_get_params(struct bgscan_learn_data *data,
	const char *params)
	{
	const char *pos;

	data->short_interval = atoi(params);

	pos = os_strchr(params, ':');
	if (pos == NULL)
	return 0;
	pos++;
	data->signal_threshold = atoi(pos);
	pos = os_strchr(pos, ':');
	if (pos == NULL) {
	wpa_printf(MSG_ERROR, "bgscan learn: Missing scan interval "
	"for high signal");
	return -1;
	}
	pos++;
	data->long_interval = atoi(pos);
	pos = os_strchr(pos, ':');
	if (pos) {
	pos++;
	data->fname = os_strdup(pos);
	}

	return 0;
	}


	static int * bgscan_learn_get_supp_freqs(struct wpa_supplicant *wpa_s)
	{
	struct hostapd_hw_modes *modes;
	int i, j, freqs = NULL, n;
	size_t count = 0;

	modes = wpa_s->hw.modes;
	if (modes == NULL)
	return NULL;

	for (i = 0; i < wpa_s->hw.num_modes; i++) {
	for (j = 0; j < modes[i].num_channels; j++) {
	if (modes[i].channels[j].flag & HOSTAPD_CHAN_DISABLED)
	continue;
	/* some hw modes (e.g. 11b & 11g) contain same freqs */
	if (in_array(freqs, modes[i].channels[j].freq))
	continue;
	n = os_realloc_array(freqs, count + 2, sizeof(int));
	if (n == NULL)
	continue;

	freqs = n;
	freqs[count] = modes[i].channels[j].freq;
	count++;
	freqs[count] = 0;
	}
	}

	return freqs;
	}


	static void * bgscan_learn_init(struct wpa_supplicant *wpa_s,
	const char *params,
	const struct wpa_ssid *ssid)
	{
	struct bgscan_learn_data *data;

	data = os_zalloc(sizeof(*data));
	if (data == NULL)
	return NULL;
	dl_list_init(&data->bss);
	data->wpa_s = wpa_s;
	data->ssid = ssid;
	if (bgscan_learn_get_params(data, params) < 0) {
	os_free(data->fname);
	os_free(data);
	return NULL;
	}
	if (data->short_interval <= 0)
	data->short_interval = 30;
	if (data->long_interval <= 0)
	data->long_interval = 30;

	if (bgscan_learn_load(data) < 0) {
	os_free(data->fname);
	os_free(data);
	return NULL;
	}

	wpa_printf(MSG_DEBUG, "bgscan learn: Signal strength threshold %d "
	"Short bgscan interval %d Long bgscan interval %d",
	data->signal_threshold, data->short_interval,
	data->long_interval);

	if (data->signal_threshold &&
	wpa_drv_signal_monitor(wpa_s, data->signal_threshold, 4) < 0) {
	wpa_printf(MSG_ERROR, "bgscan learn: Failed to enable "
	"signal strength monitoring");
	}

	data->supp_freqs = bgscan_learn_get_supp_freqs(wpa_s);
	data->scan_interval = data->short_interval;
	if (data->signal_threshold) {
	/* Poll for signal info to set initial scan interval */
	struct wpa_signal_info siginfo;
	if (wpa_drv_signal_poll(wpa_s, &siginfo) == 0 &&
	siginfo.data.signal >= data->signal_threshold)
	data->scan_interval = data->long_interval;
	}

	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
	data, NULL);

	/*
	* This function is called immediately after an association, so it is
	* reasonable to assume that a scan was completed recently. This makes
	* us skip an immediate new scan in cases where the current signal
	* level is below the bgscan threshold.
	*/
	os_get_reltime(&data->last_bgscan);

	return data;
	}


	static void bgscan_learn_deinit(void *priv)
	{
	struct bgscan_learn_data *data = priv;
	struct bgscan_learn_bss bss, n;

	bgscan_learn_save(data);
	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	if (data->signal_threshold)
	wpa_drv_signal_monitor(data->wpa_s, 0, 0);
	os_free(data->fname);
	dl_list_for_each_safe(bss, n, &data->bss, struct bgscan_learn_bss,
	list) {
	dl_list_del(&bss->list);
	bss_free(bss);
	}
	os_free(data->supp_freqs);
	os_free(data);
	}


	static int bgscan_learn_bss_match(struct bgscan_learn_data *data,
	struct wpa_scan_res *bss)
	{
	const u8 *ie;

	ie = wpa_scan_get_ie(bss, WLAN_EID_SSID);
	if (ie == NULL)
	return 0;

	if (data->ssid->ssid_len != ie[1] \|\|
	os_memcmp(data->ssid->ssid, ie + 2, ie[1]) != 0)
	return 0; /* SSID mismatch */

	return 1;
	}


	static int bgscan_learn_notify_scan(void *priv,
	struct wpa_scan_results *scan_res)
	{
	struct bgscan_learn_data *data = priv;
	size_t i, j;
	#define MAX_BSS 50
	u8 bssid[MAX_BSS * ETH_ALEN];
	size_t num_bssid = 0;

	wpa_printf(MSG_DEBUG, "bgscan learn: scan result notification");

	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
	data, NULL);

	for (i = 0; i < scan_res->num; i++) {
	struct wpa_scan_res *res = scan_res->res[i];
	if (!bgscan_learn_bss_match(data, res))
	continue;

	if (num_bssid < MAX_BSS) {
	os_memcpy(bssid + num_bssid * ETH_ALEN, res->bssid,
	ETH_ALEN);
	num_bssid++;
	}
	}
	wpa_printf(MSG_DEBUG, "bgscan learn: %u matching BSSes in scan "
	"results", (unsigned int) num_bssid);

	for (i = 0; i < scan_res->num; i++) {
	struct wpa_scan_res *res = scan_res->res[i];
	struct bgscan_learn_bss *bss;

	if (!bgscan_learn_bss_match(data, res))
	continue;

	bss = bgscan_learn_get_bss(data, res->bssid);
	if (bss && bss->freq != res->freq) {
	wpa_printf(MSG_DEBUG, "bgscan learn: Update BSS "
	MACSTR " freq %d -> %d",
	MAC2STR(res->bssid), bss->freq, res->freq);
	bss->freq = res->freq;
	} else if (!bss) {
	wpa_printf(MSG_DEBUG, "bgscan learn: Add BSS " MACSTR
	" freq=%d", MAC2STR(res->bssid), res->freq);
	bss = os_zalloc(sizeof(*bss));
	if (!bss)
	continue;
	os_memcpy(bss->bssid, res->bssid, ETH_ALEN);
	bss->freq = res->freq;
	dl_list_add(&data->bss, &bss->list);
	}

	for (j = 0; j < num_bssid; j++) {
	u8 addr = bssid + j ETH_ALEN;
	bgscan_learn_add_neighbor(bss, addr);
	}
	}

	/*
	* A more advanced bgscan could process scan results internally, select
	* the BSS and request roam if needed. This sample uses the existing
	* BSS/ESS selection routine. Change this to return 1 if selection is
	* done inside the bgscan module.
	*/

	return 0;
	}


	static void bgscan_learn_notify_beacon_loss(void *priv)
	{
	wpa_printf(MSG_DEBUG, "bgscan learn: beacon loss");
	/* TODO: speed up background scanning */
	}


	static void bgscan_learn_notify_signal_change(void *priv, int above,
	int current_signal,
	int current_noise,
	int current_txrate)
	{
	struct bgscan_learn_data *data = priv;
	int scan = 0;
	struct os_reltime now;

	if (data->short_interval == data->long_interval \|\|
	data->signal_threshold == 0)
	return;

	wpa_printf(MSG_DEBUG, "bgscan learn: signal level changed "
	"(above=%d current_signal=%d current_noise=%d "
	"current_txrate=%d)", above, current_signal,
	current_noise, current_txrate);
	if (data->scan_interval == data->long_interval && !above) {
	wpa_printf(MSG_DEBUG, "bgscan learn: Start using short bgscan "
	"interval");
	data->scan_interval = data->short_interval;
	os_get_reltime(&now);
	if (now.sec > data->last_bgscan.sec + 1)
	scan = 1;
	} else if (data->scan_interval == data->short_interval && above) {
	wpa_printf(MSG_DEBUG, "bgscan learn: Start using long bgscan "
	"interval");
	data->scan_interval = data->long_interval;
	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	eloop_register_timeout(data->scan_interval, 0,
	bgscan_learn_timeout, data, NULL);
	} else if (!above) {
	/*
	* Signal dropped further 4 dB. Request a new scan if we have
	* not yet scanned in a while.
	*/
	os_get_reltime(&now);
	if (now.sec > data->last_bgscan.sec + 10)
	scan = 1;
	}

	if (scan) {
	wpa_printf(MSG_DEBUG, "bgscan learn: Trigger immediate scan");
	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	eloop_register_timeout(0, 0, bgscan_learn_timeout, data, NULL);
	}
	}


	const struct bgscan_ops bgscan_learn_ops = {
	.name = "learn",
	.init = bgscan_learn_init,
	.deinit = bgscan_learn_deinit,
	.notify_scan = bgscan_learn_notify_scan,
	.notify_beacon_loss = bgscan_learn_notify_beacon_loss,
	.notify_signal_change = bgscan_learn_notify_signal_change,
	};