[thirdparty/hostap.git] / wpa_supplicant / bgscan_learn.c

/*
 * WPA Supplicant - background scan and roaming module: learn
 * Copyright (c) 2009-2010, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING 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_time 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(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(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 + 1;
	while (idx != data->probe_idx) {
		if (data->supp_freqs[idx] == 0)
			idx = 0;
		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;
			n = os_realloc(freqs, (count + 2) * sizeof(int));
			if (n == NULL)
				return freqs;
			freqs = n;
			freqs[count] = data->supp_freqs[idx];
			count++;
			freqs[count] = 0;
			break;
		}

		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 (ret < 0 || ret >= msg + sizeof(msg) - pos)
				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)) {
		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_time(&data->last_bgscan);
	os_free(freqs);
}


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

	if (params == NULL)
		return 0;

	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;
			n = os_realloc(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;
	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_time(&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_time 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_time(&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_time(&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,
};
Commit	Line	Data
c4d71c25 JM	1	/*
	2	* WPA Supplicant - background scan and roaming module: learn
	3	* Copyright (c) 2009-2010, Jouni Malinen <j@w1.fi>
	4	*
	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.
	8	*
	9	* Alternatively, this software may be distributed under the terms of BSD
	10	* license.
	11	*
	12	* See README and COPYING for more details.
	13	*/
	14
	15	#include "includes.h"
	16
	17	#include "common.h"
	18	#include "eloop.h"
fc480e88 JM	19	#include "list.h"
fc480e88 JM	20	#include "common/ieee802_11_defs.h"
c4d71c25 JM	21	#include "drivers/driver.h"
	22	#include "config_ssid.h"
	23	#include "wpa_supplicant_i.h"
	24	#include "driver_i.h"
	25	#include "scan.h"
	26	#include "bgscan.h"
	27
fc480e88 JM	28	struct bgscan_learn_bss {
	29	struct dl_list list;
	30	u8 bssid[ETH_ALEN];
	31	int freq;
3b7442e5 JM	32	u8 neigh; / num_neigh * ETH_ALEN buffer */
3b7442e5 JM	33	size_t num_neigh;
fc480e88 JM	34	};
fc480e88 JM	35
c4d71c25 JM	36	struct bgscan_learn_data {
	37	struct wpa_supplicant *wpa_s;
	38	const struct wpa_ssid *ssid;
	39	int scan_interval;
	40	int signal_threshold;
	41	int short_interval; /* use if signal < threshold */
	42	int long_interval; /* use if signal > threshold */
	43	struct os_time last_bgscan;
2e8d6ae3	44	char *fname;
fc480e88	45	struct dl_list bss;
2e2a8d07 JM	46	int *supp_freqs;
2e2a8d07 JM	47	int probe_idx;
c4d71c25 JM	48	};
	49
	50
3b7442e5 JM	51	static void bss_free(struct bgscan_learn_bss *bss)
	52	{
	53	os_free(bss->neigh);
	54	os_free(bss);
	55	}
	56
	57
	58	static int bssid_in_array(u8 array, size_t array_len, const u8 bssid)
	59	{
	60	size_t i;
	61
	62	if (array == NULL \|\| array_len == 0)
	63	return 0;
	64
	65	for (i = 0; i < array_len; i++) {
	66	if (os_memcmp(array + i * ETH_ALEN, bssid, ETH_ALEN) == 0)
	67	return 1;
	68	}
	69
	70	return 0;
	71	}
	72
	73
	74	static void bgscan_learn_add_neighbor(struct bgscan_learn_bss *bss,
	75	const u8 *bssid)
	76	{
	77	u8 *n;
	78
	79	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
	80	return;
	81	if (bssid_in_array(bss->neigh, bss->num_neigh, bssid))
	82	return;
	83
	84	n = os_realloc(bss->neigh, (bss->num_neigh + 1) * ETH_ALEN);
	85	if (n == NULL)
	86	return;
	87
	88	os_memcpy(n + bss->num_neigh * ETH_ALEN, bssid, ETH_ALEN);
	89	bss->neigh = n;
	90	bss->num_neigh++;
3b7442e5 JM	91	}
	92
	93
fc480e88 JM	94	static struct bgscan_learn_bss * bgscan_learn_get_bss(
	95	struct bgscan_learn_data data, const u8 bssid)
	96	{
	97	struct bgscan_learn_bss *bss;
	98
	99	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	100	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
	101	return bss;
	102	}
	103	return NULL;
	104	}
	105
	106
2e8d6ae3 JM	107	static int bgscan_learn_load(struct bgscan_learn_data *data)
	108	{
	109	FILE *f;
	110	char buf[128];
3b7442e5	111	struct bgscan_learn_bss *bss;
2e8d6ae3 JM	112
	113	if (data->fname == NULL)
	114	return 0;
	115
	116	f = fopen(data->fname, "r");
	117	if (f == NULL)
	118	return 0;
	119
	120	wpa_printf(MSG_DEBUG, "bgscan learn: Loading data from %s",
	121	data->fname);
	122
	123	if (fgets(buf, sizeof(buf), f) == NULL \|\|
	124	os_strncmp(buf, "wpa_supplicant-bgscan-learn\n", 28) != 0) {
	125	wpa_printf(MSG_INFO, "bgscan learn: Invalid data file %s",
	126	data->fname);
	127	fclose(f);
	128	return -1;
	129	}
	130
fc480e88 JM	131	while (fgets(buf, sizeof(buf), f)) {
fc480e88 JM	132	if (os_strncmp(buf, "BSS ", 4) == 0) {
fc480e88 JM	133	bss = os_zalloc(sizeof(*bss));
	134	if (!bss)
	135	continue;
	136	if (hwaddr_aton(buf + 4, bss->bssid) < 0) {
3b7442e5	137	bss_free(bss);
fc480e88 JM	138	continue;
	139	}
	140	bss->freq = atoi(buf + 4 + 18);
	141	dl_list_add(&data->bss, &bss->list);
	142	wpa_printf(MSG_DEBUG, "bgscan learn: Loaded BSS "
	143	"entry: " MACSTR " freq=%d",
	144	MAC2STR(bss->bssid), bss->freq);
	145	}
3b7442e5 JM	146
	147	if (os_strncmp(buf, "NEIGHBOR ", 9) == 0) {
	148	u8 addr[ETH_ALEN];
	149
	150	if (hwaddr_aton(buf + 9, addr) < 0)
	151	continue;
	152	bss = bgscan_learn_get_bss(data, addr);
	153	if (bss == NULL)
	154	continue;
	155	if (hwaddr_aton(buf + 9 + 18, addr) < 0)
	156	continue;
	157
	158	bgscan_learn_add_neighbor(bss, addr);
	159	}
fc480e88 JM	160	}
fc480e88 JM	161
2e8d6ae3 JM	162	fclose(f);
	163	return 0;
	164	}
	165
	166
	167	static void bgscan_learn_save(struct bgscan_learn_data *data)
	168	{
	169	FILE *f;
fc480e88	170	struct bgscan_learn_bss *bss;
2e8d6ae3 JM	171
	172	if (data->fname == NULL)
	173	return;
	174
	175	wpa_printf(MSG_DEBUG, "bgscan learn: Saving data to %s",
	176	data->fname);
	177
	178	f = fopen(data->fname, "w");
	179	if (f == NULL)
	180	return;
	181	fprintf(f, "wpa_supplicant-bgscan-learn\n");
	182
fc480e88 JM	183	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	184	fprintf(f, "BSS " MACSTR " %d\n",
	185	MAC2STR(bss->bssid), bss->freq);
	186	}
	187
3b7442e5 JM	188	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	189	size_t i;
	190	for (i = 0; i < bss->num_neigh; i++) {
	191	fprintf(f, "NEIGHBOR " MACSTR " " MACSTR "\n",
	192	MAC2STR(bss->bssid),
	193	MAC2STR(bss->neigh + i * ETH_ALEN));
	194	}
	195	}
	196
2e8d6ae3 JM	197	fclose(f);
	198	}
	199
	200
fc480e88 JM	201	static int in_array(int *array, int val)
	202	{
	203	int i;
	204
	205	if (array == NULL)
	206	return 0;
	207
	208	for (i = 0; array[i]; i++) {
	209	if (array[i] == val)
	210	return 1;
	211	}
	212
	213	return 0;
	214	}
	215
	216
	217	static int * bgscan_learn_get_freqs(struct bgscan_learn_data *data,
	218	size_t *count)
	219	{
	220	struct bgscan_learn_bss *bss;
	221	int freqs = NULL, n;
	222
	223	*count = 0;
	224
	225	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	226	if (in_array(freqs, bss->freq))
	227	continue;
	228	n = os_realloc(freqs, (count + 2) sizeof(int));
	229	if (n == NULL)
	230	return freqs;
	231	freqs = n;
	232	freqs[*count] = bss->freq;
	233	(*count)++;
	234	freqs[*count] = 0;
	235	}
	236
	237	return freqs;
	238	}
	239
	240
2e2a8d07 JM	241	static int * bgscan_learn_get_probe_freq(struct bgscan_learn_data *data,
	242	int *freqs, size_t count)
	243	{
	244	int idx, *n;
	245
	246	if (data->supp_freqs == NULL)
	247	return freqs;
	248
	249	idx = data->probe_idx + 1;
	250	while (idx != data->probe_idx) {
	251	if (data->supp_freqs[idx] == 0)
	252	idx = 0;
	253	if (!in_array(freqs, data->supp_freqs[idx])) {
	254	wpa_printf(MSG_DEBUG, "bgscan learn: Probe new freq "
	255	"%u", data->supp_freqs[idx]);
	256	data->probe_idx = idx;
	257	n = os_realloc(freqs, (count + 2) * sizeof(int));
	258	if (n == NULL)
	259	return freqs;
	260	freqs = n;
	261	freqs[count] = data->supp_freqs[idx];
	262	count++;
	263	freqs[count] = 0;
	264	break;
	265	}
	266
	267	idx++;
	268	}
	269
	270	return freqs;
	271	}
	272
	273
c4d71c25 JM	274	static void bgscan_learn_timeout(void eloop_ctx, void timeout_ctx)
	275	{
	276	struct bgscan_learn_data *data = eloop_ctx;
	277	struct wpa_supplicant *wpa_s = data->wpa_s;
	278	struct wpa_driver_scan_params params;
fc480e88	279	int *freqs = NULL;
2e2a8d07 JM	280	size_t count, i;
2e2a8d07 JM	281	char msg[100], *pos;
c4d71c25 JM	282
	283	os_memset(&params, 0, sizeof(params));
	284	params.num_ssids = 1;
	285	params.ssids[0].ssid = data->ssid->ssid;
	286	params.ssids[0].ssid_len = data->ssid->ssid_len;
fc480e88 JM	287	if (data->ssid->scan_freq)
	288	params.freqs = data->ssid->scan_freq;
	289	else {
	290	freqs = bgscan_learn_get_freqs(data, &count);
	291	wpa_printf(MSG_DEBUG, "bgscan learn: BSSes in this ESS have "
	292	"been seen on %u channels", (unsigned int) count);
2e2a8d07 JM	293	freqs = bgscan_learn_get_probe_freq(data, freqs, count);
	294
	295	msg[0] = '\0';
	296	pos = msg;
	297	for (i = 0; freqs && freqs[i]; i++) {
	298	int ret;
	299	ret = os_snprintf(pos, msg + sizeof(msg) - pos, " %d",
	300	freqs[i]);
	301	if (ret < 0 \|\| ret >= msg + sizeof(msg) - pos)
	302	break;
	303	pos += ret;
	304	}
	305	pos[0] = '\0';
	306	wpa_printf(MSG_DEBUG, "bgscan learn: Scanning frequencies:%s",
	307	msg);
fc480e88 JM	308	params.freqs = freqs;
fc480e88 JM	309	}
c4d71c25 JM	310
	311	wpa_printf(MSG_DEBUG, "bgscan learn: Request a background scan");
	312	if (wpa_supplicant_trigger_scan(wpa_s, &params)) {
	313	wpa_printf(MSG_DEBUG, "bgscan learn: Failed to trigger scan");
	314	eloop_register_timeout(data->scan_interval, 0,
	315	bgscan_learn_timeout, data, NULL);
	316	} else
	317	os_get_time(&data->last_bgscan);
fc480e88	318	os_free(freqs);
c4d71c25 JM	319	}
	320
	321
	322	static int bgscan_learn_get_params(struct bgscan_learn_data *data,
	323	const char *params)
	324	{
	325	const char *pos;
	326
	327	if (params == NULL)
	328	return 0;
	329
	330	data->short_interval = atoi(params);
	331
	332	pos = os_strchr(params, ':');
	333	if (pos == NULL)
	334	return 0;
	335	pos++;
	336	data->signal_threshold = atoi(pos);
	337	pos = os_strchr(pos, ':');
	338	if (pos == NULL) {
	339	wpa_printf(MSG_ERROR, "bgscan learn: Missing scan interval "
	340	"for high signal");
	341	return -1;
	342	}
	343	pos++;
	344	data->long_interval = atoi(pos);
2e8d6ae3 JM	345	pos = os_strchr(pos, ':');
	346	if (pos) {
	347	pos++;
	348	data->fname = os_strdup(pos);
	349	}
c4d71c25 JM	350
	351	return 0;
	352	}
	353
	354
2e2a8d07 JM	355	static int * bgscan_learn_get_supp_freqs(struct wpa_supplicant *wpa_s)
	356	{
	357	struct hostapd_hw_modes *modes;
2e2a8d07 JM	358	int i, j, freqs = NULL, n;
	359	size_t count = 0;
	360
6bf731e8 CL	361	modes = wpa_s->hw.modes;
6bf731e8 CL	362	if (modes == NULL)
2e2a8d07 JM	363	return NULL;
2e2a8d07 JM	364
6bf731e8	365	for (i = 0; i < wpa_s->hw.num_modes; i++) {
2e2a8d07 JM	366	for (j = 0; j < modes[i].num_channels; j++) {
	367	if (modes[i].channels[j].flag & HOSTAPD_CHAN_DISABLED)
	368	continue;
	369	n = os_realloc(freqs, (count + 2) * sizeof(int));
6bf731e8	370	if (n == NULL)
2e2a8d07 JM	371	continue;
	372
	373	freqs = n;
	374	freqs[count] = modes[i].channels[j].freq;
	375	count++;
	376	freqs[count] = 0;
	377	}
2e2a8d07	378	}
2e2a8d07 JM	379
	380	return freqs;
	381	}
	382
	383
c4d71c25 JM	384	static void * bgscan_learn_init(struct wpa_supplicant *wpa_s,
	385	const char *params,
	386	const struct wpa_ssid *ssid)
	387	{
	388	struct bgscan_learn_data *data;
	389
	390	data = os_zalloc(sizeof(*data));
	391	if (data == NULL)
	392	return NULL;
fc480e88	393	dl_list_init(&data->bss);
c4d71c25 JM	394	data->wpa_s = wpa_s;
	395	data->ssid = ssid;
	396	if (bgscan_learn_get_params(data, params) < 0) {
2e8d6ae3	397	os_free(data->fname);
c4d71c25 JM	398	os_free(data);
	399	return NULL;
	400	}
	401	if (data->short_interval <= 0)
	402	data->short_interval = 30;
	403	if (data->long_interval <= 0)
	404	data->long_interval = 30;
	405
2e8d6ae3 JM	406	if (bgscan_learn_load(data) < 0) {
	407	os_free(data->fname);
	408	os_free(data);
	409	return NULL;
	410	}
	411
c4d71c25 JM	412	wpa_printf(MSG_DEBUG, "bgscan learn: Signal strength threshold %d "
	413	"Short bgscan interval %d Long bgscan interval %d",
	414	data->signal_threshold, data->short_interval,
	415	data->long_interval);
	416
	417	if (data->signal_threshold &&
	418	wpa_drv_signal_monitor(wpa_s, data->signal_threshold, 4) < 0) {
	419	wpa_printf(MSG_ERROR, "bgscan learn: Failed to enable "
	420	"signal strength monitoring");
	421	}
	422
2e2a8d07	423	data->supp_freqs = bgscan_learn_get_supp_freqs(wpa_s);
c4d71c25 JM	424	data->scan_interval = data->short_interval;
	425	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
	426	data, NULL);
9ff80a10 JM	427
	428	/*
	429	* This function is called immediately after an association, so it is
	430	* reasonable to assume that a scan was completed recently. This makes
	431	* us skip an immediate new scan in cases where the current signal
	432	* level is below the bgscan threshold.
	433	*/
	434	os_get_time(&data->last_bgscan);
	435
c4d71c25 JM	436	return data;
	437	}
	438
	439
	440	static void bgscan_learn_deinit(void *priv)
	441	{
	442	struct bgscan_learn_data *data = priv;
fc480e88 JM	443	struct bgscan_learn_bss bss, n;
fc480e88 JM	444
2e8d6ae3	445	bgscan_learn_save(data);
c4d71c25 JM	446	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	447	if (data->signal_threshold)
	448	wpa_drv_signal_monitor(data->wpa_s, 0, 0);
2e8d6ae3	449	os_free(data->fname);
fc480e88 JM	450	dl_list_for_each_safe(bss, n, &data->bss, struct bgscan_learn_bss,
	451	list) {
	452	dl_list_del(&bss->list);
3b7442e5	453	bss_free(bss);
fc480e88	454	}
2e2a8d07	455	os_free(data->supp_freqs);
c4d71c25 JM	456	os_free(data);
	457	}
	458
	459
fc480e88 JM	460	static int bgscan_learn_bss_match(struct bgscan_learn_data *data,
	461	struct wpa_scan_res *bss)
	462	{
	463	const u8 *ie;
	464
	465	ie = wpa_scan_get_ie(bss, WLAN_EID_SSID);
	466	if (ie == NULL)
	467	return 0;
	468
	469	if (data->ssid->ssid_len != ie[1] \|\|
	470	os_memcmp(data->ssid->ssid, ie + 2, ie[1]) != 0)
	471	return 0; /* SSID mismatch */
	472
	473	return 1;
	474	}
	475
	476
c4d71c25 JM	477	static int bgscan_learn_notify_scan(void *priv,
	478	struct wpa_scan_results *scan_res)
	479	{
	480	struct bgscan_learn_data *data = priv;
3b7442e5 JM	481	size_t i, j;
	482	#define MAX_BSS 50
	483	u8 bssid[MAX_BSS * ETH_ALEN];
	484	size_t num_bssid = 0;
c4d71c25 JM	485
	486	wpa_printf(MSG_DEBUG, "bgscan learn: scan result notification");
	487
	488	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	489	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
	490	data, NULL);
	491
3b7442e5 JM	492	for (i = 0; i < scan_res->num; i++) {
	493	struct wpa_scan_res *res = scan_res->res[i];
	494	if (!bgscan_learn_bss_match(data, res))
	495	continue;
	496
	497	if (num_bssid < MAX_BSS) {
	498	os_memcpy(bssid + num_bssid * ETH_ALEN, res->bssid,
	499	ETH_ALEN);
	500	num_bssid++;
	501	}
	502	}
	503	wpa_printf(MSG_DEBUG, "bgscan learn: %u matching BSSes in scan "
	504	"results", (unsigned int) num_bssid);
	505
fc480e88 JM	506	for (i = 0; i < scan_res->num; i++) {
	507	struct wpa_scan_res *res = scan_res->res[i];
	508	struct bgscan_learn_bss *bss;
	509
	510	if (!bgscan_learn_bss_match(data, res))
	511	continue;
3b7442e5	512
fc480e88 JM	513	bss = bgscan_learn_get_bss(data, res->bssid);
	514	if (bss && bss->freq != res->freq) {
	515	wpa_printf(MSG_DEBUG, "bgscan learn: Update BSS "
	516	MACSTR " freq %d -> %d",
	517	MAC2STR(res->bssid), bss->freq, res->freq);
	518	bss->freq = res->freq;
	519	} else if (!bss) {
	520	wpa_printf(MSG_DEBUG, "bgscan learn: Add BSS " MACSTR
	521	" freq=%d", MAC2STR(res->bssid), res->freq);
	522	bss = os_zalloc(sizeof(*bss));
	523	if (!bss)
	524	continue;
	525	os_memcpy(bss->bssid, res->bssid, ETH_ALEN);
	526	bss->freq = res->freq;
	527	dl_list_add(&data->bss, &bss->list);
	528	}
3b7442e5 JM	529
	530	for (j = 0; j < num_bssid; j++) {
	531	u8 addr = bssid + j ETH_ALEN;
	532	bgscan_learn_add_neighbor(bss, addr);
	533	}
fc480e88 JM	534	}
fc480e88 JM	535
c4d71c25 JM	536	/*
	537	* A more advanced bgscan could process scan results internally, select
	538	* the BSS and request roam if needed. This sample uses the existing
	539	* BSS/ESS selection routine. Change this to return 1 if selection is
	540	* done inside the bgscan module.
	541	*/
	542
	543	return 0;
	544	}
	545
	546
	547	static void bgscan_learn_notify_beacon_loss(void *priv)
	548	{
	549	wpa_printf(MSG_DEBUG, "bgscan learn: beacon loss");
	550	/* TODO: speed up background scanning */
	551	}
	552
	553
60a972a6	554	static void bgscan_learn_notify_signal_change(void *priv, int above,
174fa789 PS	555	int current_signal,
	556	int current_noise,
	557	int current_txrate)
c4d71c25 JM	558	{
c4d71c25 JM	559	struct bgscan_learn_data *data = priv;
266c828e	560	int scan = 0;
9ff80a10	561	struct os_time now;
c4d71c25 JM	562
	563	if (data->short_interval == data->long_interval \|\|
	564	data->signal_threshold == 0)
	565	return;
	566
	567	wpa_printf(MSG_DEBUG, "bgscan learn: signal level changed "
174fa789 PS	568	"(above=%d current_signal=%d current_noise=%d "
	569	"current_txrate=%d)", above, current_signal,
	570	current_noise, current_txrate);
c4d71c25	571	if (data->scan_interval == data->long_interval && !above) {
9ff80a10 JM	572	wpa_printf(MSG_DEBUG, "bgscan learn: Start using short bgscan "
9ff80a10 JM	573	"interval");
c4d71c25	574	data->scan_interval = data->short_interval;
9ff80a10 JM	575	os_get_time(&now);
	576	if (now.sec > data->last_bgscan.sec + 1)
	577	scan = 1;
c4d71c25 JM	578	} else if (data->scan_interval == data->short_interval && above) {
	579	wpa_printf(MSG_DEBUG, "bgscan learn: Start using long bgscan "
	580	"interval");
	581	data->scan_interval = data->long_interval;
	582	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	583	eloop_register_timeout(data->scan_interval, 0,
	584	bgscan_learn_timeout, data, NULL);
	585	} else if (!above) {
c4d71c25 JM	586	/*
	587	* Signal dropped further 4 dB. Request a new scan if we have
	588	* not yet scanned in a while.
	589	*/
	590	os_get_time(&now);
9ff80a10 JM	591	if (now.sec > data->last_bgscan.sec + 10)
	592	scan = 1;
	593	}
	594
	595	if (scan) {
	596	wpa_printf(MSG_DEBUG, "bgscan learn: Trigger immediate scan");
	597	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	598	eloop_register_timeout(0, 0, bgscan_learn_timeout, data, NULL);
c4d71c25 JM	599	}
	600	}
	601
	602
	603	const struct bgscan_ops bgscan_learn_ops = {
	604	.name = "learn",
	605	.init = bgscan_learn_init,
	606	.deinit = bgscan_learn_deinit,
	607	.notify_scan = bgscan_learn_notify_scan,
	608	.notify_beacon_loss = bgscan_learn_notify_beacon_loss,
	609	.notify_signal_change = bgscan_learn_notify_signal_change,
	610	};