* 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.
+ * 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 "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 signal_threshold;
int short_interval; /* use if signal < threshold */
int long_interval; /* use if signal > threshold */
- struct os_time last_bgscan;
+ 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;
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;
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(¶ms, 0, sizeof(params));
params.num_ssids = 1;
params.ssids[0].ssid = data->ssid->ssid;
params.ssids[0].ssid_len = data->ssid->ssid_len;
- params.freqs = data->ssid->scan_freq;
-
- /*
- * A more advanced bgscan module would learn about most like channels
- * over time and request scans only for some channels (probing others
- * every now and then) to reduce effect on the data connection.
- */
+ 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, ¶ms)) {
eloop_register_timeout(data->scan_interval, 0,
bgscan_learn_timeout, data, NULL);
} else
- os_get_time(&data->last_bgscan);
+ os_get_reltime(&data->last_bgscan);
+ os_free(freqs);
}
}
+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)
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) {
"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.current_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_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
}
-static void bgscan_learn_notify_signal_change(void *priv, int above)
+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)", above);
+ "(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: Trigger immediate scan "
- "and start using short bgscan interval");
+ wpa_printf(MSG_DEBUG, "bgscan learn: Start using short bgscan "
+ "interval");
data->scan_interval = data->short_interval;
- eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
- eloop_register_timeout(0, 0, bgscan_learn_timeout, data,
- NULL);
+ 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");
eloop_register_timeout(data->scan_interval, 0,
bgscan_learn_timeout, data, NULL);
} else if (!above) {
- struct os_time now;
/*
* 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) {
- 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);
- }
+ 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);
}
}
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