adv_monitor: Implement RSSI filtering and content matching

This implements the following logic for background scanning.
- Implement RSSI tracking based on high/low RSSI thresholds and timers.
- Create an entry point in adapter to start the matching of Adv based
on all monitors and invoke the RSSI tracking for Adv reporting.

1 files changed, 406 insertions, 37 deletions

diff --git a/src/adv_monitor.c b/src/adv_monitor.c
index e441a5566..9a04da6e1 100644
--- a/src/adv_monitor.c
+++ b/src/adv_monitor.c
@@ -26,9 +26,9 @@
 
 #include "adapter.h"
 #include "dbus-common.h"
+#include "device.h"
 #include "log.h"
 #include "src/error.h"
-#include "src/shared/ad.h"
 #include "src/shared/mgmt.h"
 #include "src/shared/queue.h"
 #include "src/shared/util.h"
@@ -81,13 +81,6 @@ enum monitor_state {
 	MONITOR_STATE_HONORED,	/* Accepted by kernel */
 };
 
-struct pattern {
-	uint8_t ad_type;
-	uint8_t offset;
-	uint8_t length;
-	uint8_t value[BT_AD_MAX_DATA_LEN];
-};
-
 struct adv_monitor {
 	struct adv_monitor_app *app;
 	GDBusProxy *proxy;
@@ -95,13 +88,34 @@ struct adv_monitor {
 
 	enum monitor_state state;	/* MONITOR_STATE_* */
 
-	int8_t high_rssi;		/* high RSSI threshold */
-	uint16_t high_rssi_timeout;	/* high RSSI threshold timeout */
-	int8_t low_rssi;		/* low RSSI threshold */
-	uint16_t low_rssi_timeout;	/* low RSSI threshold timeout */
+	int8_t high_rssi;		/* High RSSI threshold */
+	uint16_t high_rssi_timeout;	/* High RSSI threshold timeout */
+	int8_t low_rssi;		/* Low RSSI threshold */
+	uint16_t low_rssi_timeout;	/* Low RSSI threshold timeout */
+	struct queue *devices;		/* List of adv_monitor_device objects */
 
 	enum monitor_type type;		/* MONITOR_TYPE_* */
-	struct queue *patterns;
+	struct queue *patterns;		/* List of bt_ad_pattern objects */
+};
+
+/* Some data like last_seen, timer/timeout values need to be maintained
+ * per device. struct adv_monitor_device maintains such data.
+ */
+struct adv_monitor_device {
+	struct adv_monitor *monitor;
+	struct btd_device *device;
+
+	time_t high_rssi_first_seen;	/* Start time when RSSI climbs above
+					 * the high RSSI threshold
+					 */
+	time_t low_rssi_first_seen;	/* Start time when RSSI drops below
+					 * the low RSSI threshold
+					 */
+	time_t last_seen;		/* Time when last Adv was received */
+	bool found;			/* State of the device - lost/found */
+	guint lost_timer;		/* Timer to track if the device goes
+					 * offline/out-of-range
+					 */
 };
 
 struct app_match_data {
@@ -109,6 +123,20 @@ struct app_match_data {
 	const char *path;
 };
 
+struct adv_content_filter_info {
+	struct bt_ad *ad;
+	struct queue *matched_monitors;	/* List of matched monitors */
+};
+
+struct adv_rssi_filter_info {
+	struct btd_device *device;
+	int8_t rssi;
+};
+
+static void monitor_device_free(void *data);
+static void adv_monitor_filter_rssi(struct adv_monitor *monitor,
+					struct btd_device *device, int8_t rssi);
+
 const struct adv_monitor_type {
 	enum monitor_type type;
 	const char *name;
@@ -131,10 +159,7 @@ static void app_reply_msg(struct adv_monitor_app *app, DBusMessage *reply)
 /* Frees a pattern */
 static void pattern_free(void *data)
 {
-	struct pattern *pattern = data;
-
-	if (!pattern)
-		return;
+	struct bt_ad_pattern *pattern = data;
 
 	free(pattern);
 }
@@ -150,6 +175,9 @@ static void monitor_free(void *data)
 	g_dbus_proxy_unref(monitor->proxy);
 	g_free(monitor->path);
 
+	queue_destroy(monitor->devices, monitor_device_free);
+	monitor->devices = NULL;
+
 	queue_destroy(monitor->patterns, pattern_free);
 
 	free(monitor);
@@ -248,6 +276,7 @@ static struct adv_monitor *monitor_new(struct adv_monitor_app *app,
 	monitor->high_rssi_timeout = ADV_MONITOR_UNSET_TIMER;
 	monitor->low_rssi = ADV_MONITOR_UNSET_RSSI;
 	monitor->low_rssi_timeout = ADV_MONITOR_UNSET_TIMER;
+	monitor->devices = queue_new();
 
 	monitor->type = MONITOR_TYPE_NONE;
 	monitor->patterns = NULL;
@@ -436,7 +465,7 @@ static bool parse_patterns(struct adv_monitor *monitor, const char *path)
 		int value_len;
 		uint8_t *value;
 		uint8_t offset, ad_type;
-		struct pattern *pattern;
+		struct bt_ad_pattern *pattern;
 		DBusMessageIter struct_iter, value_iter;
 
 		dbus_message_iter_recurse(&array_iter, &struct_iter);
@@ -468,28 +497,10 @@ static bool parse_patterns(struct adv_monitor *monitor, const char *path)
 		dbus_message_iter_get_fixed_array(&value_iter, &value,
 							&value_len);
 
-		// Verify the values
-		if (offset > BT_AD_MAX_DATA_LEN - 1)
-			goto failed;
-
-		if ((ad_type > BT_AD_3D_INFO_DATA &&
-			ad_type != BT_AD_MANUFACTURER_DATA) ||
-			ad_type < BT_AD_FLAGS) {
-			goto failed;
-		}
-
-		if (!value || value_len <= 0 || value_len > BT_AD_MAX_DATA_LEN)
-			goto failed;
-
-		pattern = new0(struct pattern, 1);
+		pattern = bt_ad_pattern_new(ad_type, offset, value_len, value);
 		if (!pattern)
 			goto failed;
 
-		pattern->ad_type = ad_type;
-		pattern->offset = offset;
-		pattern->length = value_len;
-		memcpy(pattern->value, value, pattern->length);
-
 		queue_push_tail(monitor->patterns, pattern);
 
 		dbus_message_iter_next(&array_iter);
@@ -923,3 +934,361 @@ void btd_adv_monitor_manager_destroy(struct btd_adv_monitor_manager *manager)
 
 	manager_destroy(manager);
 }
+
+/* Processes the content matching based pattern(s) of a monitor */
+static void adv_match_per_monitor(void *data, void *user_data)
+{
+	struct adv_monitor *monitor = data;
+	struct adv_content_filter_info *info = user_data;
+
+	if (!monitor) {
+		error("Unexpected NULL adv_monitor object upon match");
+		return;
+	}
+
+	if (monitor->state != MONITOR_STATE_HONORED)
+		return;
+
+	if (monitor->type == MONITOR_TYPE_OR_PATTERNS &&
+		bt_ad_pattern_match(info->ad, monitor->patterns)) {
+		goto matched;
+	}
+
+	return;
+
+matched:
+	if (!info->matched_monitors)
+		info->matched_monitors = queue_new();
+
+	queue_push_tail(info->matched_monitors, monitor);
+}
+
+/* Processes the content matching for the monitor(s) of an app */
+static void adv_match_per_app(void *data, void *user_data)
+{
+	struct adv_monitor_app *app = data;
+
+	if (!app) {
+		error("Unexpected NULL adv_monitor_app object upon match");
+		return;
+	}
+
+	queue_foreach(app->monitors, adv_match_per_monitor, user_data);
+}
+
+/* Processes the content matching for every app without RSSI filtering and
+ * notifying monitors. The caller is responsible of releasing the memory of the
+ * list but not the ad data.
+ * Returns the list of monitors whose content match the ad data.
+ */
+struct queue *btd_adv_monitor_content_filter(
+				struct btd_adv_monitor_manager *manager,
+				struct bt_ad *ad)
+{
+	struct adv_content_filter_info info;
+
+	if (!manager || !ad)
+		return NULL;
+
+	info.ad = ad;
+	info.matched_monitors = NULL;
+
+	queue_foreach(manager->apps, adv_match_per_app, &info);
+
+	return info.matched_monitors;
+}
+
+/* Wraps adv_monitor_filter_rssi() to processes the content-matched monitor with
+ * RSSI filtering and notifies it on device found/lost event
+ */
+static void monitor_filter_rssi(void *data, void *user_data)
+{
+	struct adv_monitor *monitor = data;
+	struct adv_rssi_filter_info *info = user_data;
+
+	if (!monitor || !info)
+		return;
+
+	adv_monitor_filter_rssi(monitor, info->device, info->rssi);
+}
+
+/* Processes every content-matched monitor with RSSI filtering and notifies on
+ * device found/lost event. The caller is responsible of releasing the memory
+ * of matched_monitors list but not its data.
+ */
+void btd_adv_monitor_notify_monitors(struct btd_adv_monitor_manager *manager,
+					struct btd_device *device, int8_t rssi,
+					struct queue *matched_monitors)
+{
+	struct adv_rssi_filter_info info;
+
+	if (!manager || !device || !matched_monitors ||
+		queue_isempty(matched_monitors)) {
+		return;
+	}
+
+	info.device = device;
+	info.rssi = rssi;
+
+	queue_foreach(matched_monitors, monitor_filter_rssi, &info);
+}
+
+/* Matches a device based on btd_device object */
+static bool monitor_device_match(const void *a, const void *b)
+{
+	const struct adv_monitor_device *dev = a;
+	const struct btd_device *device = b;
+
+	if (!dev) {
+		error("Unexpected NULL adv_monitor_device object upon match");
+		return false;
+	}
+
+	if (dev->device != device)
+		return false;
+
+	return true;
+}
+
+/* Frees a monitor device object */
+static void monitor_device_free(void *data)
+{
+	struct adv_monitor_device *dev = data;
+
+	if (!dev) {
+		error("Unexpected NULL adv_monitor_device object upon free");
+		return;
+	}
+
+	if (dev->lost_timer) {
+		g_source_remove(dev->lost_timer);
+		dev->lost_timer = 0;
+	}
+
+	dev->monitor = NULL;
+	dev->device = NULL;
+
+	free(dev);
+}
+
+/* Removes a device from monitor->devices list */
+static void remove_device_from_monitor(void *data, void *user_data)
+{
+	struct adv_monitor *monitor = data;
+	struct btd_device *device = user_data;
+	struct adv_monitor_device *dev = NULL;
+
+	if (!monitor) {
+		error("Unexpected NULL adv_monitor object upon device remove");
+		return;
+	}
+
+	dev = queue_remove_if(monitor->devices, monitor_device_match, device);
+	if (dev) {
+		DBG("Device removed from the Adv Monitor at path %s",
+		    monitor->path);
+		monitor_device_free(dev);
+	}
+}
+
+/* Removes a device from every monitor in an app */
+static void remove_device_from_app(void *data, void *user_data)
+{
+	struct adv_monitor_app *app = data;
+	struct btd_device *device = user_data;
+
+	if (!app) {
+		error("Unexpected NULL adv_monitor_app object upon device "
+			"remove");
+		return;
+	}
+
+	queue_foreach(app->monitors, remove_device_from_monitor, device);
+}
+
+/* Removes a device from every monitor in all apps */
+void btd_adv_monitor_device_remove(struct btd_adv_monitor_manager *manager,
+				   struct btd_device *device)
+{
+	if (!manager || !device)
+		return;
+
+	queue_foreach(manager->apps, remove_device_from_app, device);
+}
+
+/* Creates a device object to track the per-device information */
+static struct adv_monitor_device *monitor_device_create(
+			struct adv_monitor *monitor,
+			struct btd_device *device)
+{
+	struct adv_monitor_device *dev = NULL;
+
+	dev = new0(struct adv_monitor_device, 1);
+	if (!dev)
+		return NULL;
+
+	dev->monitor = monitor;
+	dev->device = device;
+
+	queue_push_tail(monitor->devices, dev);
+
+	return dev;
+}
+
+/* Includes found/lost device's object path into the dbus message */
+static void report_device_state_setup(DBusMessageIter *iter, void *user_data)
+{
+	const char *path = device_get_path(user_data);
+
+	dbus_message_iter_append_basic(iter, DBUS_TYPE_OBJECT_PATH, &path);
+}
+
+/* Handles a situation where the device goes offline/out-of-range */
+static gboolean handle_device_lost_timeout(gpointer user_data)
+{
+	struct adv_monitor_device *dev = user_data;
+	struct adv_monitor *monitor = dev->monitor;
+	time_t curr_time = time(NULL);
+
+	DBG("Device Lost timeout triggered for device %p "
+	    "for the Adv Monitor at path %s", dev->device, monitor->path);
+
+	dev->lost_timer = 0;
+
+	if (dev->found && dev->last_seen) {
+		/* We were tracking for the Low RSSI filter. Check if there is
+		 * any Adv received after the timeout function is invoked.
+		 * If not, report the Device Lost event.
+		 */
+		if (difftime(curr_time, dev->last_seen) >=
+		    monitor->low_rssi_timeout) {
+			dev->found = false;
+
+			DBG("Calling DeviceLost() on Adv Monitor of owner %s "
+			    "at path %s", monitor->app->owner, monitor->path);
+
+			g_dbus_proxy_method_call(monitor->proxy, "DeviceLost",
+						 report_device_state_setup,
+						 NULL, dev->device, NULL);
+		}
+	}
+
+	return FALSE;
+}
+
+/* Filters an Adv based on its RSSI value */
+static void adv_monitor_filter_rssi(struct adv_monitor *monitor,
+				    struct btd_device *device, int8_t rssi)
+{
+	struct adv_monitor_device *dev = NULL;
+	time_t curr_time = time(NULL);
+	uint16_t adapter_id = monitor->app->manager->adapter_id;
+
+	/* If the RSSI thresholds and timeouts are not specified, report the
+	 * DeviceFound() event without tracking for the RSSI as the Adv has
+	 * already matched the pattern filter.
+	 */
+	if (monitor->high_rssi == ADV_MONITOR_UNSET_RSSI &&
+		monitor->low_rssi == ADV_MONITOR_UNSET_RSSI &&
+		monitor->high_rssi_timeout == ADV_MONITOR_UNSET_TIMER &&
+		monitor->low_rssi_timeout == ADV_MONITOR_UNSET_TIMER) {
+		DBG("Calling DeviceFound() on Adv Monitor of owner %s "
+		    "at path %s", monitor->app->owner, monitor->path);
+
+		g_dbus_proxy_method_call(monitor->proxy, "DeviceFound",
+					 report_device_state_setup, NULL,
+					 device, NULL);
+
+		return;
+	}
+
+	dev = queue_find(monitor->devices, monitor_device_match, device);
+	if (!dev) {
+		dev = monitor_device_create(monitor, device);
+		if (!dev) {
+			btd_error(adapter_id, "Failed to create Adv Monitor "
+					      "device object.");
+			return;
+		}
+	}
+
+	if (dev->lost_timer) {
+		g_source_remove(dev->lost_timer);
+		dev->lost_timer = 0;
+	}
+
+	/* Reset the timings of found/lost if a device has been offline for
+	 * longer than the high/low timeouts.
+	 */
+	if (dev->last_seen) {
+		if (difftime(curr_time, dev->last_seen) >
+		    monitor->high_rssi_timeout) {
+			dev->high_rssi_first_seen = 0;
+		}
+
+		if (difftime(curr_time, dev->last_seen) >
+		    monitor->low_rssi_timeout) {
+			dev->low_rssi_first_seen = 0;
+		}
+	}
+	dev->last_seen = curr_time;
+
+	/* Check for the found devices (if the device is not already found) */
+	if (!dev->found && rssi > monitor->high_rssi) {
+		if (dev->high_rssi_first_seen) {
+			if (difftime(curr_time, dev->high_rssi_first_seen) >=
+			    monitor->high_rssi_timeout) {
+				dev->found = true;
+
+				DBG("Calling DeviceFound() on Adv Monitor "
+				    "of owner %s at path %s",
+				    monitor->app->owner, monitor->path);
+
+				g_dbus_proxy_method_call(
+					monitor->proxy, "DeviceFound",
+					report_device_state_setup, NULL,
+					dev->device, NULL);
+			}
+		} else {
+			dev->high_rssi_first_seen = curr_time;
+		}
+	} else {
+		dev->high_rssi_first_seen = 0;
+	}
+
+	/* Check for the lost devices (only if the device is already found, as
+	 * it doesn't make any sense to report the Device Lost event if the
+	 * device is not found yet)
+	 */
+	if (dev->found && rssi < monitor->low_rssi) {
+		if (dev->low_rssi_first_seen) {
+			if (difftime(curr_time, dev->low_rssi_first_seen) >=
+			    monitor->low_rssi_timeout) {
+				dev->found = false;
+
+				DBG("Calling DeviceLost() on Adv Monitor "
+				    "of owner %s at path %s",
+				    monitor->app->owner, monitor->path);
+
+				g_dbus_proxy_method_call(
+					monitor->proxy, "DeviceLost",
+					report_device_state_setup, NULL,
+					dev->device, NULL);
+			}
+		} else {
+			dev->low_rssi_first_seen = curr_time;
+		}
+	} else {
+		dev->low_rssi_first_seen = 0;
+	}
+
+	/* Setup a timer to track if the device goes offline/out-of-range, only
+	 * if we are tracking for the Low RSSI Threshold. If we are tracking
+	 * the High RSSI Threshold, nothing needs to be done.
+	 */
+	if (dev->found) {
+		dev->lost_timer =
+			g_timeout_add_seconds(monitor->low_rssi_timeout,
+					      handle_device_lost_timeout, dev);
+	}
+}