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From:   Miao-chen Chou <mcchou@chromium.org>
To:     Bluetooth Kernel Mailing List <linux-bluetooth@vger.kernel.org>
Cc:     Manish Mandlik <mmandlik@chromium.org>,
        Howard Chung <howardchung@google.com>,
        Luiz Augusto von Dentz <luiz.von.dentz@intel.com>,
        Alain Michaud <alainm@chromium.org>,
        Miao-chen Chou <mcchou@chromium.org>
Subject: [BlueZ PATCH v5 7/8] adv_monitor: Handle D-Bus proxy event of an ADV monitor
Date:   Fri, 11 Sep 2020 23:51:31 -0700
Message-Id: <20200911235104.BlueZ.v5.7.I47744c7eef31f44cf393dea2b3e437d7b41cef79@changeid>
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References: <20200911235104.BlueZ.v5.1.Iaa9dc2a66de5fbfa97627e1dbeb800116d3aa91e@changeid>
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This adds two handlers, one for adding and one for removing, of D-Bus proxy
events. The handler of property changes is set to NULL as intended,
since for simplicity no further changes on monitor's properties would
affect the ongoing monitoring.

The following test steps were performed with bluetoothctl.
- After registering the root path, expose two monitors and verify that
the proxy added event are received.
- Have two monitors added, unexpose the monitors, and verify that the
proxy removed events are received for those two monitors.
- Have two monitors added, unregister the monitors and verify that the
proxy removed events are received for those two monitors.

Reviewed-by: Yun-Hao Chung <howardchung@google.com>
Reviewed-by: Manish Mandlik <mmandlik@chromium.org>
---

Changes in v5:
- Removed unused variable and added parentheses
- Use g_strcmp0() instead of strcmp() due to const char *

Changes in v2:
- Use new0() instead of g_new0()
- Remove the reset of monitor members
- Use memcpy() instead of g_memmove()

 src/adv_monitor.c | 487 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 474 insertions(+), 13 deletions(-)

diff --git a/src/adv_monitor.c b/src/adv_monitor.c
index b42a47b9c..737da1c90 100644
--- a/src/adv_monitor.c
+++ b/src/adv_monitor.c
@@ -37,14 +37,23 @@
 #include "dbus-common.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"
 
 #include "adv_monitor.h"
 
+#define ADV_MONITOR_INTERFACE		"org.bluez.AdvertisementMonitor1"
 #define ADV_MONITOR_MGR_INTERFACE	"org.bluez.AdvertisementMonitorManager1"
 
+#define ADV_MONITOR_UNSET_RSSI		127	/* dBm */
+#define ADV_MONITOR_MAX_RSSI		20	/* dBm */
+#define ADV_MONITOR_MIN_RSSI		-127	/* dBm */
+#define ADV_MONITOR_UNSET_TIMER		0	/* second */
+#define ADV_MONITOR_MIN_TIMER		1	/* second */
+#define ADV_MONITOR_MAX_TIMER		300	/* second */
+
 struct btd_adv_monitor_manager {
 	struct btd_adapter *adapter;
 	struct mgmt *mgmt;
@@ -65,6 +74,43 @@ struct adv_monitor_app {
 
 	DBusMessage *reg;
 	GDBusClient *client;
+
+	struct queue *monitors;
+};
+
+enum monitor_type {
+	MONITOR_TYPE_NONE,
+	MONITOR_TYPE_OR_PATTERNS,
+};
+
+enum monitor_state {
+	MONITOR_STATE_NEW,	/* New but not yet init'ed with actual values */
+	MONITOR_STATE_FAILED,	/* Failed to be init'ed */
+	MONITOR_STATE_INITED,	/* Init'ed but not yet sent to kernel */
+	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;
+	char *path;
+
+	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 */
+
+	enum monitor_type type;		/* MONITOR_TYPE_* */
+	struct queue *patterns;
 };
 
 struct app_match_data {
@@ -72,6 +118,14 @@ struct app_match_data {
 	const char *path;
 };
 
+const struct adv_monitor_type {
+	enum monitor_type type;
+	const char *name;
+} supported_types[] = {
+	{ MONITOR_TYPE_OR_PATTERNS, "or_patterns" },
+	{ },
+};
+
 /* Replies to an app's D-Bus message and unref it */
 static void app_reply_msg(struct adv_monitor_app *app, DBusMessage *reply)
 {
@@ -83,6 +137,48 @@ static void app_reply_msg(struct adv_monitor_app *app, DBusMessage *reply)
 	app->reg = NULL;
 }
 
+/* Frees a pattern */
+static void pattern_free(void *data)
+{
+	struct pattern *pattern = data;
+
+	if (!pattern)
+		return;
+
+	free(pattern);
+}
+
+/* Frees a monitor object */
+static void monitor_free(void *data)
+{
+	struct adv_monitor *monitor = data;
+
+	if (!monitor)
+		return;
+
+	g_dbus_proxy_unref(monitor->proxy);
+	g_free(monitor->path);
+
+	queue_destroy(monitor->patterns, pattern_free);
+
+	free(monitor);
+}
+
+/* Calls Release() method of the remote Adv Monitor */
+static void monitor_release(void *data, void *user_data)
+{
+	struct adv_monitor *monitor = data;
+
+	if (!monitor)
+		return;
+
+	DBG("Calling Release() on Adv Monitor of owner %s at path %s",
+		monitor->app->owner, monitor->path);
+
+	g_dbus_proxy_method_call(monitor->proxy, "Release", NULL, NULL, NULL,
+					NULL);
+}
+
 /* Destroys an app object along with related D-Bus handlers */
 static void app_destroy(void *data)
 {
@@ -93,6 +189,9 @@ static void app_destroy(void *data)
 
 	DBG("Destroy Adv Monitor app %s at path %s", app->owner, app->path);
 
+	queue_foreach(app->monitors, monitor_release, NULL);
+	queue_destroy(app->monitors, monitor_free);
+
 	if (app->reg) {
 		app_reply_msg(app, btd_error_failed(app->reg,
 						"Adv Monitor app destroyed"));
@@ -135,6 +234,371 @@ static void app_ready_cb(GDBusClient *client, void *user_data)
 	app_reply_msg(app, dbus_message_new_method_return(app->reg));
 }
 
+/* Allocates an Adv Monitor */
+static struct adv_monitor *monitor_new(struct adv_monitor_app *app,
+						GDBusProxy *proxy)
+{
+	struct adv_monitor *monitor;
+
+	if (!app || !proxy)
+		return NULL;
+
+	monitor = new0(struct adv_monitor, 1);
+	if (!monitor)
+		return NULL;
+
+	monitor->app = app;
+	monitor->proxy = g_dbus_proxy_ref(proxy);
+	monitor->path = g_strdup(g_dbus_proxy_get_path(proxy));
+
+	monitor->state = MONITOR_STATE_NEW;
+
+	monitor->high_rssi = ADV_MONITOR_UNSET_RSSI;
+	monitor->high_rssi_timeout = ADV_MONITOR_UNSET_TIMER;
+	monitor->low_rssi = ADV_MONITOR_UNSET_RSSI;
+	monitor->low_rssi_timeout = ADV_MONITOR_UNSET_TIMER;
+
+	monitor->type = MONITOR_TYPE_NONE;
+	monitor->patterns = NULL;
+
+	return monitor;
+}
+
+/* Matches a monitor based on its D-Bus path */
+static bool monitor_match(const void *a, const void *b)
+{
+	const GDBusProxy *proxy = b;
+	const struct adv_monitor *monitor = a;
+
+	if (!proxy || !monitor)
+		return false;
+
+	if (g_strcmp0(g_dbus_proxy_get_path(proxy), monitor->path) != 0)
+		return false;
+
+	return true;
+}
+
+/* Retrieves Type from the remote Adv Monitor object, verifies the value and
+ * update the local Adv Monitor
+ */
+static bool parse_monitor_type(struct adv_monitor *monitor, const char *path)
+{
+	DBusMessageIter iter;
+	const struct adv_monitor_type *t;
+	const char *type_str;
+	uint16_t adapter_id = monitor->app->manager->adapter_id;
+
+	if (!g_dbus_proxy_get_property(monitor->proxy, "Type", &iter)) {
+		btd_error(adapter_id, "Failed to retrieve property Type from "
+			"the Adv Monitor at path %s", path);
+		return false;
+	}
+
+	if (dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_STRING)
+		goto failed;
+
+	dbus_message_iter_get_basic(&iter, &type_str);
+
+	for (t = supported_types; t->name; t++) {
+		if (strcmp(t->name, type_str) == 0) {
+			monitor->type = t->type;
+			return true;
+		}
+	}
+
+failed:
+	btd_error(adapter_id, "Invalid argument of property Type of the Adv "
+			"Monitor at path %s", path);
+
+	return false;
+}
+
+/* Retrieves RSSIThresholdsAndTimers from the remote Adv Monitor object,
+ * verifies the values and update the local Adv Monitor
+ */
+static bool parse_rssi_and_timeout(struct adv_monitor *monitor,
+					const char *path)
+{
+	DBusMessageIter prop_struct, iter;
+	int16_t h_rssi, l_rssi;
+	uint16_t h_rssi_timer, l_rssi_timer;
+	uint16_t adapter_id = monitor->app->manager->adapter_id;
+
+	/* Property RSSIThresholdsAndTimers is optional */
+	if (!g_dbus_proxy_get_property(monitor->proxy,
+					"RSSIThresholdsAndTimers",
+					&prop_struct)) {
+		DBG("Adv Monitor at path %s provides no RSSI thresholds and "
+			"timeouts", path);
+		return true;
+	}
+
+	if (dbus_message_iter_get_arg_type(&prop_struct) != DBUS_TYPE_STRUCT)
+		goto failed;
+
+	dbus_message_iter_recurse(&prop_struct, &iter);
+
+	/* Extract HighRSSIThreshold */
+	if (dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_INT16)
+		goto failed;
+	dbus_message_iter_get_basic(&iter, &h_rssi);
+	if (!dbus_message_iter_next(&iter))
+		goto failed;
+
+	/* Extract HighRSSIThresholdTimer */
+	if (dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_UINT16)
+		goto failed;
+	dbus_message_iter_get_basic(&iter, &h_rssi_timer);
+	if (!dbus_message_iter_next(&iter))
+		goto failed;
+
+	/* Extract LowRSSIThreshold */
+	if (dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_INT16)
+		goto failed;
+	dbus_message_iter_get_basic(&iter, &l_rssi);
+	if (!dbus_message_iter_next(&iter))
+		goto failed;
+
+	/* Extract LowRSSIThresholdTimer */
+	if (dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_UINT16)
+		goto failed;
+	dbus_message_iter_get_basic(&iter, &l_rssi_timer);
+
+	/* Verify the values of RSSIs and their timers. For simplicity, we
+	 * enforce the all-or-none rule to these fields. In other words, either
+	 * all are set to the unset values or all are set within valid ranges.
+	 */
+	if (h_rssi == ADV_MONITOR_UNSET_RSSI &&
+		l_rssi == ADV_MONITOR_UNSET_RSSI &&
+		h_rssi_timer == ADV_MONITOR_UNSET_TIMER &&
+		l_rssi_timer == ADV_MONITOR_UNSET_TIMER) {
+		goto done;
+	}
+
+	if (h_rssi < ADV_MONITOR_MIN_RSSI || h_rssi > ADV_MONITOR_MAX_RSSI ||
+		l_rssi < ADV_MONITOR_MIN_RSSI ||
+		l_rssi > ADV_MONITOR_MAX_RSSI || h_rssi <= l_rssi) {
+		goto failed;
+	}
+
+	if (h_rssi_timer < ADV_MONITOR_MIN_TIMER ||
+		h_rssi_timer > ADV_MONITOR_MAX_TIMER ||
+		l_rssi_timer < ADV_MONITOR_MIN_TIMER ||
+		l_rssi_timer > ADV_MONITOR_MAX_TIMER) {
+		goto failed;
+	}
+
+	monitor->high_rssi = h_rssi;
+	monitor->low_rssi = l_rssi;
+	monitor->high_rssi_timeout = h_rssi_timer;
+	monitor->low_rssi_timeout = l_rssi_timer;
+
+done:
+	DBG("Adv Monitor at %s initiated with high RSSI threshold %d, high "
+		"RSSI threshold timeout %d, low RSSI threshold %d, low RSSI "
+		"threshold timeout %d", path, monitor->high_rssi,
+		monitor->high_rssi_timeout, monitor->low_rssi,
+		monitor->low_rssi_timeout);
+
+	return true;
+
+failed:
+	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;
+
+	btd_error(adapter_id, "Invalid argument of property "
+			"RSSIThresholdsAndTimers of the Adv Monitor at path %s",
+			path);
+
+	return false;
+}
+
+/* Retrieves Patterns from the remote Adv Monitor object, verifies the values
+ * and update the local Adv Monitor
+ */
+static bool parse_patterns(struct adv_monitor *monitor, const char *path)
+{
+	DBusMessageIter array, array_iter;
+	uint16_t adapter_id = monitor->app->manager->adapter_id;
+
+	if (!g_dbus_proxy_get_property(monitor->proxy, "Patterns", &array)) {
+		btd_error(adapter_id, "Failed to retrieve property Patterns "
+				"from the Adv Monitor at path %s", path);
+		return false;
+	}
+
+	monitor->patterns = queue_new();
+
+	if (dbus_message_iter_get_arg_type(&array) != DBUS_TYPE_ARRAY ||
+		dbus_message_iter_get_element_type(&array) !=
+		DBUS_TYPE_STRUCT) {
+		goto failed;
+	}
+
+	dbus_message_iter_recurse(&array, &array_iter);
+
+	while (dbus_message_iter_get_arg_type(&array_iter) ==
+		DBUS_TYPE_STRUCT) {
+		int value_len;
+		uint8_t *value;
+		uint8_t offset, ad_type;
+		struct pattern *pattern;
+		DBusMessageIter struct_iter, value_iter;
+
+		dbus_message_iter_recurse(&array_iter, &struct_iter);
+
+		// Extract start position
+		if (dbus_message_iter_get_arg_type(&struct_iter) !=
+			DBUS_TYPE_BYTE) {
+			goto failed;
+		}
+		dbus_message_iter_get_basic(&struct_iter, &offset);
+		if (!dbus_message_iter_next(&struct_iter))
+			goto failed;
+
+		// Extract AD data type
+		if (dbus_message_iter_get_arg_type(&struct_iter) !=
+			DBUS_TYPE_BYTE) {
+			goto failed;
+		}
+		dbus_message_iter_get_basic(&struct_iter, &ad_type);
+		if (!dbus_message_iter_next(&struct_iter))
+			goto failed;
+
+		// Extract value of a pattern
+		if (dbus_message_iter_get_arg_type(&struct_iter) !=
+			DBUS_TYPE_ARRAY) {
+			goto failed;
+		}
+		dbus_message_iter_recurse(&struct_iter, &value_iter);
+		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);
+		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);
+	}
+
+	/* There must be at least one pattern. */
+	if (queue_isempty(monitor->patterns))
+		goto failed;
+
+	return true;
+
+failed:
+	queue_destroy(monitor->patterns, pattern_free);
+	monitor->patterns = NULL;
+
+	btd_error(adapter_id, "Invalid argument of property Patterns of the "
+			"Adv Monitor at path %s", path);
+
+	return false;
+}
+
+/* Processes the content of the remote Adv Monitor */
+static bool monitor_process(struct adv_monitor *monitor,
+				struct adv_monitor_app *app)
+{
+	const char *path = g_dbus_proxy_get_path(monitor->proxy);
+
+	monitor->state = MONITOR_STATE_FAILED;
+
+	if (!parse_monitor_type(monitor, path))
+		goto done;
+
+	if (!parse_rssi_and_timeout(monitor, path))
+		goto done;
+
+	if (monitor->type == MONITOR_TYPE_OR_PATTERNS &&
+		parse_patterns(monitor, path)) {
+		monitor->state = MONITOR_STATE_INITED;
+	}
+
+done:
+	return monitor->state != MONITOR_STATE_FAILED;
+}
+
+/* Handles an Adv Monitor D-Bus proxy added event */
+static void monitor_proxy_added_cb(GDBusProxy *proxy, void *user_data)
+{
+	struct adv_monitor *monitor;
+	struct adv_monitor_app *app = user_data;
+	uint16_t adapter_id = app->manager->adapter_id;
+	const char *path = g_dbus_proxy_get_path(proxy);
+	const char *iface = g_dbus_proxy_get_interface(proxy);
+
+	if (strcmp(iface, ADV_MONITOR_INTERFACE) != 0 ||
+		!g_str_has_prefix(path, app->path)) {
+		return;
+	}
+
+	if (queue_find(app->monitors, monitor_match, proxy)) {
+		btd_error(adapter_id, "Adv Monitor proxy already exists with "
+				"path %s", path);
+		return;
+	}
+
+	monitor = monitor_new(app, proxy);
+	if (!monitor) {
+		btd_error(adapter_id, "Failed to allocate an Adv Monitor for "
+				"the object at %s", path);
+		return;
+	}
+
+	if (!monitor_process(monitor, app)) {
+		monitor_release(monitor, NULL);
+		monitor_free(monitor);
+		DBG("Adv Monitor at path %s released due to invalid content",
+			path);
+		return;
+	}
+
+	queue_push_tail(app->monitors, monitor);
+
+	DBG("Adv Monitor allocated for the object at path %s", path);
+}
+
+/* Handles the removal of an Adv Monitor D-Bus proxy */
+static void monitor_proxy_removed_cb(GDBusProxy *proxy, void *user_data)
+{
+	struct adv_monitor *monitor;
+	struct adv_monitor_app *app = user_data;
+
+	monitor = queue_remove_if(app->monitors, monitor_match, proxy);
+	if (monitor) {
+		DBG("Adv Monitor removed for the object at path %s",
+			monitor->path);
+
+		/* The object was gone, so we don't need to call Release() */
+		monitor_free(monitor);
+	}
+}
+
 /* Creates an app object, initiates it and sets D-Bus event handlers */
 static struct adv_monitor_app *app_create(DBusConnection *conn,
 					DBusMessage *msg, const char *sender,
@@ -161,8 +625,17 @@ static struct adv_monitor_app *app_create(DBusConnection *conn,
 		return NULL;
 	}
 
+	app->monitors = queue_new();
+
 	g_dbus_client_set_disconnect_watch(app->client, app_disconnect_cb, app);
-	g_dbus_client_set_proxy_handlers(app->client, NULL, NULL, NULL, NULL);
+
+	/* Note that any property changes on a monitor object would not affect
+	 * the content of the corresponding monitor.
+	 */
+	g_dbus_client_set_proxy_handlers(app->client, monitor_proxy_added_cb,
+						monitor_proxy_removed_cb, NULL,
+						app);
+
 	g_dbus_client_set_ready_watch(app->client, app_ready_cb, app);
 
 	app->reg = dbus_message_ref(msg);
@@ -269,18 +742,6 @@ static const GDBusMethodTable adv_monitor_methods[] = {
 	{ }
 };
 
-enum monitor_type {
-	MONITOR_TYPE_OR_PATTERNS,
-};
-
-const struct adv_monitor_type {
-	enum monitor_type type;
-	const char *name;
-} supported_types[] = {
-	{ MONITOR_TYPE_OR_PATTERNS, "or_patterns" },
-	{ },
-};
-
 /* Gets SupportedMonitorTypes property */
 static gboolean get_supported_monitor_types(const GDBusPropertyTable *property,
 						DBusMessageIter *iter,
-- 
2.26.2