[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 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_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_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 + 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_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++;
	}

	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_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;
	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	*
0f3d578e JM	5	* This software may be distributed under the terms of the BSD license.
0f3d578e JM	6	* See README for more details.
c4d71c25 JM	7	*/
	8
	9	#include "includes.h"
	10
	11	#include "common.h"
	12	#include "eloop.h"
fc480e88 JM	13	#include "list.h"
fc480e88 JM	14	#include "common/ieee802_11_defs.h"
c4d71c25 JM	15	#include "drivers/driver.h"
	16	#include "config_ssid.h"
	17	#include "wpa_supplicant_i.h"
	18	#include "driver_i.h"
	19	#include "scan.h"
	20	#include "bgscan.h"
	21
fc480e88 JM	22	struct bgscan_learn_bss {
	23	struct dl_list list;
	24	u8 bssid[ETH_ALEN];
	25	int freq;
3b7442e5 JM	26	u8 neigh; / num_neigh * ETH_ALEN buffer */
3b7442e5 JM	27	size_t num_neigh;
fc480e88 JM	28	};
fc480e88 JM	29
c4d71c25 JM	30	struct bgscan_learn_data {
	31	struct wpa_supplicant *wpa_s;
	32	const struct wpa_ssid *ssid;
	33	int scan_interval;
	34	int signal_threshold;
	35	int short_interval; /* use if signal < threshold */
	36	int long_interval; /* use if signal > threshold */
	37	struct os_time last_bgscan;
2e8d6ae3	38	char *fname;
fc480e88	39	struct dl_list bss;
2e2a8d07 JM	40	int *supp_freqs;
2e2a8d07 JM	41	int probe_idx;
c4d71c25 JM	42	};
	43
	44
3b7442e5 JM	45	static void bss_free(struct bgscan_learn_bss *bss)
	46	{
	47	os_free(bss->neigh);
	48	os_free(bss);
	49	}
	50
	51
	52	static int bssid_in_array(u8 array, size_t array_len, const u8 bssid)
	53	{
	54	size_t i;
	55
	56	if (array == NULL \|\| array_len == 0)
	57	return 0;
	58
	59	for (i = 0; i < array_len; i++) {
	60	if (os_memcmp(array + i * ETH_ALEN, bssid, ETH_ALEN) == 0)
	61	return 1;
	62	}
	63
	64	return 0;
	65	}
	66
	67
	68	static void bgscan_learn_add_neighbor(struct bgscan_learn_bss *bss,
	69	const u8 *bssid)
	70	{
	71	u8 *n;
	72
	73	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
	74	return;
	75	if (bssid_in_array(bss->neigh, bss->num_neigh, bssid))
	76	return;
	77
067ffa26	78	n = os_realloc_array(bss->neigh, bss->num_neigh + 1, ETH_ALEN);
3b7442e5 JM	79	if (n == NULL)
	80	return;
	81
	82	os_memcpy(n + bss->num_neigh * ETH_ALEN, bssid, ETH_ALEN);
	83	bss->neigh = n;
	84	bss->num_neigh++;
3b7442e5 JM	85	}
	86
	87
fc480e88 JM	88	static struct bgscan_learn_bss * bgscan_learn_get_bss(
	89	struct bgscan_learn_data data, const u8 bssid)
	90	{
	91	struct bgscan_learn_bss *bss;
	92
	93	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	94	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
	95	return bss;
	96	}
	97	return NULL;
	98	}
	99
	100
2e8d6ae3 JM	101	static int bgscan_learn_load(struct bgscan_learn_data *data)
	102	{
	103	FILE *f;
	104	char buf[128];
3b7442e5	105	struct bgscan_learn_bss *bss;
2e8d6ae3 JM	106
	107	if (data->fname == NULL)
	108	return 0;
	109
	110	f = fopen(data->fname, "r");
	111	if (f == NULL)
	112	return 0;
	113
	114	wpa_printf(MSG_DEBUG, "bgscan learn: Loading data from %s",
	115	data->fname);
	116
	117	if (fgets(buf, sizeof(buf), f) == NULL \|\|
	118	os_strncmp(buf, "wpa_supplicant-bgscan-learn\n", 28) != 0) {
	119	wpa_printf(MSG_INFO, "bgscan learn: Invalid data file %s",
	120	data->fname);
	121	fclose(f);
	122	return -1;
	123	}
	124
fc480e88 JM	125	while (fgets(buf, sizeof(buf), f)) {
fc480e88 JM	126	if (os_strncmp(buf, "BSS ", 4) == 0) {
fc480e88 JM	127	bss = os_zalloc(sizeof(*bss));
	128	if (!bss)
	129	continue;
	130	if (hwaddr_aton(buf + 4, bss->bssid) < 0) {
3b7442e5	131	bss_free(bss);
fc480e88 JM	132	continue;
	133	}
	134	bss->freq = atoi(buf + 4 + 18);
	135	dl_list_add(&data->bss, &bss->list);
	136	wpa_printf(MSG_DEBUG, "bgscan learn: Loaded BSS "
	137	"entry: " MACSTR " freq=%d",
	138	MAC2STR(bss->bssid), bss->freq);
	139	}
3b7442e5 JM	140
	141	if (os_strncmp(buf, "NEIGHBOR ", 9) == 0) {
	142	u8 addr[ETH_ALEN];
	143
	144	if (hwaddr_aton(buf + 9, addr) < 0)
	145	continue;
	146	bss = bgscan_learn_get_bss(data, addr);
	147	if (bss == NULL)
	148	continue;
	149	if (hwaddr_aton(buf + 9 + 18, addr) < 0)
	150	continue;
	151
	152	bgscan_learn_add_neighbor(bss, addr);
	153	}
fc480e88 JM	154	}
fc480e88 JM	155
2e8d6ae3 JM	156	fclose(f);
	157	return 0;
	158	}
	159
	160
	161	static void bgscan_learn_save(struct bgscan_learn_data *data)
	162	{
	163	FILE *f;
fc480e88	164	struct bgscan_learn_bss *bss;
2e8d6ae3 JM	165
	166	if (data->fname == NULL)
	167	return;
	168
	169	wpa_printf(MSG_DEBUG, "bgscan learn: Saving data to %s",
	170	data->fname);
	171
	172	f = fopen(data->fname, "w");
	173	if (f == NULL)
	174	return;
	175	fprintf(f, "wpa_supplicant-bgscan-learn\n");
	176
fc480e88 JM	177	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	178	fprintf(f, "BSS " MACSTR " %d\n",
	179	MAC2STR(bss->bssid), bss->freq);
	180	}
	181
3b7442e5 JM	182	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	183	size_t i;
	184	for (i = 0; i < bss->num_neigh; i++) {
	185	fprintf(f, "NEIGHBOR " MACSTR " " MACSTR "\n",
	186	MAC2STR(bss->bssid),
	187	MAC2STR(bss->neigh + i * ETH_ALEN));
	188	}
	189	}
	190
2e8d6ae3 JM	191	fclose(f);
	192	}
	193
	194
fc480e88 JM	195	static int in_array(int *array, int val)
	196	{
	197	int i;
	198
	199	if (array == NULL)
	200	return 0;
	201
	202	for (i = 0; array[i]; i++) {
	203	if (array[i] == val)
	204	return 1;
	205	}
	206
	207	return 0;
	208	}
	209
	210
	211	static int * bgscan_learn_get_freqs(struct bgscan_learn_data *data,
	212	size_t *count)
	213	{
	214	struct bgscan_learn_bss *bss;
	215	int freqs = NULL, n;
	216
	217	*count = 0;
	218
	219	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	220	if (in_array(freqs, bss->freq))
	221	continue;
067ffa26	222	n = os_realloc_array(freqs, *count + 2, sizeof(int));
fc480e88 JM	223	if (n == NULL)
	224	return freqs;
	225	freqs = n;
	226	freqs[*count] = bss->freq;
	227	(*count)++;
	228	freqs[*count] = 0;
	229	}
	230
	231	return freqs;
	232	}
	233
	234
2e2a8d07 JM	235	static int * bgscan_learn_get_probe_freq(struct bgscan_learn_data *data,
	236	int *freqs, size_t count)
	237	{
	238	int idx, *n;
	239
	240	if (data->supp_freqs == NULL)
	241	return freqs;
	242
	243	idx = data->probe_idx + 1;
	244	while (idx != data->probe_idx) {
	245	if (data->supp_freqs[idx] == 0)
	246	idx = 0;
	247	if (!in_array(freqs, data->supp_freqs[idx])) {
	248	wpa_printf(MSG_DEBUG, "bgscan learn: Probe new freq "
	249	"%u", data->supp_freqs[idx]);
	250	data->probe_idx = idx;
067ffa26	251	n = os_realloc_array(freqs, count + 2, sizeof(int));
2e2a8d07 JM	252	if (n == NULL)
	253	return freqs;
	254	freqs = n;
	255	freqs[count] = data->supp_freqs[idx];
	256	count++;
	257	freqs[count] = 0;
	258	break;
	259	}
	260
	261	idx++;
	262	}
	263
	264	return freqs;
	265	}
	266
	267
c4d71c25 JM	268	static void bgscan_learn_timeout(void eloop_ctx, void timeout_ctx)
	269	{
	270	struct bgscan_learn_data *data = eloop_ctx;
	271	struct wpa_supplicant *wpa_s = data->wpa_s;
	272	struct wpa_driver_scan_params params;
fc480e88	273	int *freqs = NULL;
2e2a8d07 JM	274	size_t count, i;
2e2a8d07 JM	275	char msg[100], *pos;
c4d71c25 JM	276
	277	os_memset(&params, 0, sizeof(params));
	278	params.num_ssids = 1;
	279	params.ssids[0].ssid = data->ssid->ssid;
	280	params.ssids[0].ssid_len = data->ssid->ssid_len;
fc480e88 JM	281	if (data->ssid->scan_freq)
	282	params.freqs = data->ssid->scan_freq;
	283	else {
	284	freqs = bgscan_learn_get_freqs(data, &count);
	285	wpa_printf(MSG_DEBUG, "bgscan learn: BSSes in this ESS have "
	286	"been seen on %u channels", (unsigned int) count);
2e2a8d07 JM	287	freqs = bgscan_learn_get_probe_freq(data, freqs, count);
	288
	289	msg[0] = '\0';
	290	pos = msg;
	291	for (i = 0; freqs && freqs[i]; i++) {
	292	int ret;
	293	ret = os_snprintf(pos, msg + sizeof(msg) - pos, " %d",
	294	freqs[i]);
	295	if (ret < 0 \|\| ret >= msg + sizeof(msg) - pos)
	296	break;
	297	pos += ret;
	298	}
	299	pos[0] = '\0';
	300	wpa_printf(MSG_DEBUG, "bgscan learn: Scanning frequencies:%s",
	301	msg);
fc480e88 JM	302	params.freqs = freqs;
fc480e88 JM	303	}
c4d71c25 JM	304
	305	wpa_printf(MSG_DEBUG, "bgscan learn: Request a background scan");
	306	if (wpa_supplicant_trigger_scan(wpa_s, &params)) {
	307	wpa_printf(MSG_DEBUG, "bgscan learn: Failed to trigger scan");
	308	eloop_register_timeout(data->scan_interval, 0,
	309	bgscan_learn_timeout, data, NULL);
	310	} else
	311	os_get_time(&data->last_bgscan);
fc480e88	312	os_free(freqs);
c4d71c25 JM	313	}
	314
	315
	316	static int bgscan_learn_get_params(struct bgscan_learn_data *data,
	317	const char *params)
	318	{
	319	const char *pos;
	320
	321	if (params == NULL)
	322	return 0;
	323
	324	data->short_interval = atoi(params);
	325
	326	pos = os_strchr(params, ':');
	327	if (pos == NULL)
	328	return 0;
	329	pos++;
	330	data->signal_threshold = atoi(pos);
	331	pos = os_strchr(pos, ':');
	332	if (pos == NULL) {
	333	wpa_printf(MSG_ERROR, "bgscan learn: Missing scan interval "
	334	"for high signal");
	335	return -1;
	336	}
	337	pos++;
	338	data->long_interval = atoi(pos);
2e8d6ae3 JM	339	pos = os_strchr(pos, ':');
	340	if (pos) {
	341	pos++;
	342	data->fname = os_strdup(pos);
	343	}
c4d71c25 JM	344
	345	return 0;
	346	}
	347
	348
2e2a8d07 JM	349	static int * bgscan_learn_get_supp_freqs(struct wpa_supplicant *wpa_s)
	350	{
	351	struct hostapd_hw_modes *modes;
2e2a8d07 JM	352	int i, j, freqs = NULL, n;
	353	size_t count = 0;
	354
6bf731e8 CL	355	modes = wpa_s->hw.modes;
6bf731e8 CL	356	if (modes == NULL)
2e2a8d07 JM	357	return NULL;
2e2a8d07 JM	358
6bf731e8	359	for (i = 0; i < wpa_s->hw.num_modes; i++) {
2e2a8d07 JM	360	for (j = 0; j < modes[i].num_channels; j++) {
	361	if (modes[i].channels[j].flag & HOSTAPD_CHAN_DISABLED)
	362	continue;
067ffa26	363	n = os_realloc_array(freqs, count + 2, sizeof(int));
6bf731e8	364	if (n == NULL)
2e2a8d07 JM	365	continue;
	366
	367	freqs = n;
	368	freqs[count] = modes[i].channels[j].freq;
	369	count++;
	370	freqs[count] = 0;
	371	}
2e2a8d07	372	}
2e2a8d07 JM	373
	374	return freqs;
	375	}
	376
	377
c4d71c25 JM	378	static void * bgscan_learn_init(struct wpa_supplicant *wpa_s,
	379	const char *params,
	380	const struct wpa_ssid *ssid)
	381	{
	382	struct bgscan_learn_data *data;
	383
	384	data = os_zalloc(sizeof(*data));
	385	if (data == NULL)
	386	return NULL;
fc480e88	387	dl_list_init(&data->bss);
c4d71c25 JM	388	data->wpa_s = wpa_s;
	389	data->ssid = ssid;
	390	if (bgscan_learn_get_params(data, params) < 0) {
2e8d6ae3	391	os_free(data->fname);
c4d71c25 JM	392	os_free(data);
	393	return NULL;
	394	}
	395	if (data->short_interval <= 0)
	396	data->short_interval = 30;
	397	if (data->long_interval <= 0)
	398	data->long_interval = 30;
	399
2e8d6ae3 JM	400	if (bgscan_learn_load(data) < 0) {
	401	os_free(data->fname);
	402	os_free(data);
	403	return NULL;
	404	}
	405
c4d71c25 JM	406	wpa_printf(MSG_DEBUG, "bgscan learn: Signal strength threshold %d "
	407	"Short bgscan interval %d Long bgscan interval %d",
	408	data->signal_threshold, data->short_interval,
	409	data->long_interval);
	410
	411	if (data->signal_threshold &&
	412	wpa_drv_signal_monitor(wpa_s, data->signal_threshold, 4) < 0) {
	413	wpa_printf(MSG_ERROR, "bgscan learn: Failed to enable "
	414	"signal strength monitoring");
	415	}
	416
2e2a8d07	417	data->supp_freqs = bgscan_learn_get_supp_freqs(wpa_s);
c4d71c25 JM	418	data->scan_interval = data->short_interval;
	419	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
	420	data, NULL);
9ff80a10 JM	421
	422	/*
	423	* This function is called immediately after an association, so it is
	424	* reasonable to assume that a scan was completed recently. This makes
	425	* us skip an immediate new scan in cases where the current signal
	426	* level is below the bgscan threshold.
	427	*/
	428	os_get_time(&data->last_bgscan);
	429
c4d71c25 JM	430	return data;
	431	}
	432
	433
	434	static void bgscan_learn_deinit(void *priv)
	435	{
	436	struct bgscan_learn_data *data = priv;
fc480e88 JM	437	struct bgscan_learn_bss bss, n;
fc480e88 JM	438
2e8d6ae3	439	bgscan_learn_save(data);
c4d71c25 JM	440	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	441	if (data->signal_threshold)
	442	wpa_drv_signal_monitor(data->wpa_s, 0, 0);
2e8d6ae3	443	os_free(data->fname);
fc480e88 JM	444	dl_list_for_each_safe(bss, n, &data->bss, struct bgscan_learn_bss,
	445	list) {
	446	dl_list_del(&bss->list);
3b7442e5	447	bss_free(bss);
fc480e88	448	}
2e2a8d07	449	os_free(data->supp_freqs);
c4d71c25 JM	450	os_free(data);
	451	}
	452
	453
fc480e88 JM	454	static int bgscan_learn_bss_match(struct bgscan_learn_data *data,
	455	struct wpa_scan_res *bss)
	456	{
	457	const u8 *ie;
	458
	459	ie = wpa_scan_get_ie(bss, WLAN_EID_SSID);
	460	if (ie == NULL)
	461	return 0;
	462
	463	if (data->ssid->ssid_len != ie[1] \|\|
	464	os_memcmp(data->ssid->ssid, ie + 2, ie[1]) != 0)
	465	return 0; /* SSID mismatch */
	466
	467	return 1;
	468	}
	469
	470
c4d71c25 JM	471	static int bgscan_learn_notify_scan(void *priv,
	472	struct wpa_scan_results *scan_res)
	473	{
	474	struct bgscan_learn_data *data = priv;
3b7442e5 JM	475	size_t i, j;
	476	#define MAX_BSS 50
	477	u8 bssid[MAX_BSS * ETH_ALEN];
	478	size_t num_bssid = 0;
c4d71c25 JM	479
	480	wpa_printf(MSG_DEBUG, "bgscan learn: scan result notification");
	481
	482	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	483	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
	484	data, NULL);
	485
3b7442e5 JM	486	for (i = 0; i < scan_res->num; i++) {
	487	struct wpa_scan_res *res = scan_res->res[i];
	488	if (!bgscan_learn_bss_match(data, res))
	489	continue;
	490
	491	if (num_bssid < MAX_BSS) {
	492	os_memcpy(bssid + num_bssid * ETH_ALEN, res->bssid,
	493	ETH_ALEN);
	494	num_bssid++;
	495	}
	496	}
	497	wpa_printf(MSG_DEBUG, "bgscan learn: %u matching BSSes in scan "
	498	"results", (unsigned int) num_bssid);
	499
fc480e88 JM	500	for (i = 0; i < scan_res->num; i++) {
	501	struct wpa_scan_res *res = scan_res->res[i];
	502	struct bgscan_learn_bss *bss;
	503
	504	if (!bgscan_learn_bss_match(data, res))
	505	continue;
3b7442e5	506
fc480e88 JM	507	bss = bgscan_learn_get_bss(data, res->bssid);
	508	if (bss && bss->freq != res->freq) {
	509	wpa_printf(MSG_DEBUG, "bgscan learn: Update BSS "
	510	MACSTR " freq %d -> %d",
	511	MAC2STR(res->bssid), bss->freq, res->freq);
	512	bss->freq = res->freq;
	513	} else if (!bss) {
	514	wpa_printf(MSG_DEBUG, "bgscan learn: Add BSS " MACSTR
	515	" freq=%d", MAC2STR(res->bssid), res->freq);
	516	bss = os_zalloc(sizeof(*bss));
	517	if (!bss)
	518	continue;
	519	os_memcpy(bss->bssid, res->bssid, ETH_ALEN);
	520	bss->freq = res->freq;
	521	dl_list_add(&data->bss, &bss->list);
	522	}
3b7442e5 JM	523
	524	for (j = 0; j < num_bssid; j++) {
	525	u8 addr = bssid + j ETH_ALEN;
	526	bgscan_learn_add_neighbor(bss, addr);
	527	}
fc480e88 JM	528	}
fc480e88 JM	529
c4d71c25 JM	530	/*
	531	* A more advanced bgscan could process scan results internally, select
	532	* the BSS and request roam if needed. This sample uses the existing
	533	* BSS/ESS selection routine. Change this to return 1 if selection is
	534	* done inside the bgscan module.
	535	*/
	536
	537	return 0;
	538	}
	539
	540
	541	static void bgscan_learn_notify_beacon_loss(void *priv)
	542	{
	543	wpa_printf(MSG_DEBUG, "bgscan learn: beacon loss");
	544	/* TODO: speed up background scanning */
	545	}
	546
	547
60a972a6	548	static void bgscan_learn_notify_signal_change(void *priv, int above,
174fa789 PS	549	int current_signal,
	550	int current_noise,
	551	int current_txrate)
c4d71c25 JM	552	{
c4d71c25 JM	553	struct bgscan_learn_data *data = priv;
266c828e	554	int scan = 0;
9ff80a10	555	struct os_time now;
c4d71c25 JM	556
	557	if (data->short_interval == data->long_interval \|\|
	558	data->signal_threshold == 0)
	559	return;
	560
	561	wpa_printf(MSG_DEBUG, "bgscan learn: signal level changed "
174fa789 PS	562	"(above=%d current_signal=%d current_noise=%d "
	563	"current_txrate=%d)", above, current_signal,
	564	current_noise, current_txrate);
c4d71c25	565	if (data->scan_interval == data->long_interval && !above) {
9ff80a10 JM	566	wpa_printf(MSG_DEBUG, "bgscan learn: Start using short bgscan "
9ff80a10 JM	567	"interval");
c4d71c25	568	data->scan_interval = data->short_interval;
9ff80a10 JM	569	os_get_time(&now);
	570	if (now.sec > data->last_bgscan.sec + 1)
	571	scan = 1;
c4d71c25 JM	572	} else if (data->scan_interval == data->short_interval && above) {
	573	wpa_printf(MSG_DEBUG, "bgscan learn: Start using long bgscan "
	574	"interval");
	575	data->scan_interval = data->long_interval;
	576	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	577	eloop_register_timeout(data->scan_interval, 0,
	578	bgscan_learn_timeout, data, NULL);
	579	} else if (!above) {
c4d71c25 JM	580	/*
	581	* Signal dropped further 4 dB. Request a new scan if we have
	582	* not yet scanned in a while.
	583	*/
	584	os_get_time(&now);
9ff80a10 JM	585	if (now.sec > data->last_bgscan.sec + 10)
	586	scan = 1;
	587	}
	588
	589	if (scan) {
	590	wpa_printf(MSG_DEBUG, "bgscan learn: Trigger immediate scan");
	591	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	592	eloop_register_timeout(0, 0, bgscan_learn_timeout, data, NULL);
c4d71c25 JM	593	}
	594	}
	595
	596
	597	const struct bgscan_ops bgscan_learn_ops = {
	598	.name = "learn",
	599	.init = bgscan_learn_init,
	600	.deinit = bgscan_learn_deinit,
	601	.notify_scan = bgscan_learn_notify_scan,
	602	.notify_beacon_loss = bgscan_learn_notify_beacon_loss,
	603	.notify_signal_change = bgscan_learn_notify_signal_change,
	604	};