gatt: Implement Robust Caching handling for server

This detects when a client becomes change-unware returning
DB Out of Sync error when that happens.

1 files changed, 71 insertions, 4 deletions

diff --git a/src/gatt-database.c b/src/gatt-database.c
index c86f247ab..5aaf5c690 100644
--- a/src/gatt-database.c
+++ b/src/gatt-database.c
@@ -180,6 +180,8 @@ struct device_state {
 	uint8_t bdaddr_type;
 	unsigned int disc_id;
 	uint8_t cli_feat[1];
+	bool change_aware;
+	bool out_of_sync;
 	struct queue *ccc_states;
 	struct notify *pending;
 };
@@ -328,6 +330,7 @@ static void att_disconnected(int err, void *user_data)
 	DBG("");
 
 	state->disc_id = 0;
+	state->out_of_sync = false;
 
 	device = btd_adapter_find_device(state->db->adapter, &state->bdaddr,
 							state->bdaddr_type);
@@ -1119,10 +1122,13 @@ static void cli_feat_write_cb(struct gatt_db_attribute *attrib,
 	/* Shall we reallocate the feat array if bigger? */
 	len = MIN(sizeof(state->cli_feat), len);
 	while (len) {
-		state->cli_feat[len - 1] |= value[len -1];
+		state->cli_feat[len - 1] |= value[len - 1];
 		len--;
 	}
 
+	state->cli_feat[0] &= BT_GATT_CHRC_CLI_FEAT_ROBUST_CACHING;
+	state->change_aware = true;
+
 done:
 	gatt_db_attribute_write_result(attrib, id, ecode);
 }
@@ -1134,12 +1140,22 @@ static void db_hash_read_cb(struct gatt_db_attribute *attrib,
 {
 	struct btd_gatt_database *database = user_data;
 	const uint8_t *hash;
+	struct device_state *state;
+	bdaddr_t bdaddr;
+	uint8_t bdaddr_type;
 
 	DBG("Database Hash read");
 
 	hash = gatt_db_get_hash(database->db);
 
 	gatt_db_attribute_read_result(attrib, id, 0, hash, 16);
+
+	if (!get_dst_info(att, &bdaddr, &bdaddr_type))
+		return;
+
+	state = find_device_state(database, &bdaddr, bdaddr_type);
+	if (state)
+		state->change_aware = true;
 }
 
 static void populate_gatt_service(struct btd_gatt_database *database)
@@ -1197,7 +1213,14 @@ static void conf_cb(void *user_data)
 
 static void service_changed_conf(void *user_data)
 {
+	struct device_state *state = user_data;
+
 	DBG("");
+
+	if (!state)
+		return;
+
+	state->change_aware = true;
 }
 
 static void state_set_pending(struct device_state *state, struct notify *notify)
@@ -1239,6 +1262,14 @@ static void send_notification_to_device(void *data, void *user_data)
 	struct btd_device *device;
 	struct bt_gatt_server *server;
 
+	if (notify->conf == service_changed_conf) {
+		if (device_state->cli_feat[0] &
+				BT_GATT_CHRC_CLI_FEAT_ROBUST_CACHING) {
+			device_state->change_aware = false;
+			notify->user_data = device_state;
+		}
+	}
+
 	ccc = find_ccc_state(device_state, notify->ccc_handle);
 	if (!ccc)
 		return;
@@ -3432,6 +3463,40 @@ static const GDBusMethodTable manager_methods[] = {
 	{ }
 };
 
+static uint8_t server_authorize(struct bt_att *att, uint8_t opcode,
+					uint16_t handle, void *user_data)
+{
+	struct btd_gatt_database *database = user_data;
+	struct device_state *state;
+	bdaddr_t bdaddr;
+	uint8_t bdaddr_type;
+
+	if (!get_dst_info(att, &bdaddr, &bdaddr_type))
+		return 0;
+
+	/* Skip if there is no device state */
+	state = find_device_state(database, &bdaddr, bdaddr_type);
+	if (!state)
+		return 0;
+
+	/* Skip if client doesn't support Robust Caching */
+	if (!(state->cli_feat[0] & BT_GATT_CHRC_CLI_FEAT_ROBUST_CACHING))
+		return 0;
+
+	if (state->change_aware)
+		return 0;
+
+	if (state->out_of_sync) {
+		state->out_of_sync = false;
+		state->change_aware = true;
+		return 0;
+	}
+
+	state->out_of_sync = true;
+
+	return BT_ATT_ERROR_DB_OUT_OF_SYNC;
+}
+
 struct btd_gatt_database *btd_gatt_database_new(struct btd_adapter *adapter)
 {
 	struct btd_gatt_database *database;
@@ -3493,7 +3558,6 @@ struct btd_gatt_database *btd_gatt_database_new(struct btd_adapter *adapter)
 	if (!database->db_id)
 		goto fail;
 
-
 	return database;
 
 fail:
@@ -3522,9 +3586,10 @@ struct gatt_db *btd_gatt_database_get_db(struct btd_gatt_database *database)
 	return database->db;
 }
 
-void btd_gatt_database_att_connected(struct btd_gatt_database *database,
-						struct bt_att *att)
+void btd_gatt_database_server_connected(struct btd_gatt_database *database,
+						struct bt_gatt_server *server)
 {
+	struct bt_att *att = bt_gatt_server_get_att(server);
 	struct device_state *state;
 	bdaddr_t bdaddr;
 	uint8_t bdaddr_type;
@@ -3532,6 +3597,8 @@ void btd_gatt_database_att_connected(struct btd_gatt_database *database,
 	if (!get_dst_info(att, &bdaddr, &bdaddr_type))
 		return;
 
+	bt_gatt_server_set_authorize(server, server_authorize, database);
+
 	state = find_device_state(database, &bdaddr, bdaddr_type);
 	if (!state || !state->pending)
 		return;