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authorJouni Malinen <j@w1.fi>2010-07-10 22:55:48 (GMT)
committerJouni Malinen <j@w1.fi>2010-07-10 22:55:48 (GMT)
commitc4d71c25057465e18941b57765b45f5626b9e314 (patch)
treeaecf22001913cadbd24ab54996b2b01ee4a7973e /wpa_supplicant/bgscan_learn.c
parentc2594c3677c8f529febe31600afb95e61d8b39bb (diff)
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bgscan: Add starting point for more advanced bgscan module: learn
This is based on the bgscan "simple" module and this initial commit does not add any new functionality.
Diffstat (limited to 'wpa_supplicant/bgscan_learn.c')
-rw-r--r--wpa_supplicant/bgscan_learn.c220
1 files changed, 220 insertions, 0 deletions
diff --git a/wpa_supplicant/bgscan_learn.c b/wpa_supplicant/bgscan_learn.c
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+++ b/wpa_supplicant/bgscan_learn.c
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+/*
+ * 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 "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_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;
+};
+
+
+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;
+
+ 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;
+ 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.
+ */
+
+ 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);
+}
+
+
+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);
+
+ return 0;
+}
+
+
+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;
+ data->wpa_s = wpa_s;
+ data->ssid = ssid;
+ if (bgscan_learn_get_params(data, params) < 0) {
+ os_free(data);
+ return NULL;
+ }
+ if (data->short_interval <= 0)
+ data->short_interval = 30;
+ if (data->long_interval <= 0)
+ data->long_interval = 30;
+
+ 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->scan_interval = data->short_interval;
+ eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
+ data, NULL);
+ return data;
+}
+
+
+static void bgscan_learn_deinit(void *priv)
+{
+ struct bgscan_learn_data *data = priv;
+ eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
+ if (data->signal_threshold)
+ wpa_drv_signal_monitor(data->wpa_s, 0, 0);
+ os_free(data);
+}
+
+
+static int bgscan_learn_notify_scan(void *priv,
+ struct wpa_scan_results *scan_res)
+{
+ struct bgscan_learn_data *data = priv;
+
+ 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);
+
+ /*
+ * 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)
+{
+ struct bgscan_learn_data *data = priv;
+
+ if (data->short_interval == data->long_interval ||
+ data->signal_threshold == 0)
+ return;
+
+ wpa_printf(MSG_DEBUG, "bgscan learn: signal level changed "
+ "(above=%d)", above);
+ if (data->scan_interval == data->long_interval && !above) {
+ wpa_printf(MSG_DEBUG, "bgscan learn: Trigger immediate scan "
+ "and 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);
+ } 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) {
+ 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);
+ }
+ }
+}
+
+
+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,
+};