mgmtd: implement YANG RPC/action support

lib/mgmt.proto

@@ -79,6 +79,7 @@ message BeSubscribeReq {
   repeated string config_xpaths = 2;
   repeated string oper_xpaths = 3;
   repeated string notif_xpaths = 4;
+  repeated string rpc_xpaths = 5;
 }
 
 message BeSubscribeReply {

lib/mgmt_be_client.c

@@ -915,6 +915,143 @@ static void be_client_handle_get_tree(struct mgmt_be_client *client,
 		   be_client_send_tree_data_batch, args);
 }
 
+static void be_client_send_rpc_reply(struct mgmt_be_client *client,
+				     uint64_t txn_id, uint64_t req_id,
+				     uint8_t result_type,
+				     struct lyd_node *output)
+{
+	struct mgmt_msg_rpc_reply *rpc_reply_msg;
+	uint8_t **darrp;
+	LY_ERR err;
+	int ret = NB_OK;
+
+	rpc_reply_msg = mgmt_msg_native_alloc_msg(struct mgmt_msg_rpc_reply, 0,
+						  MTYPE_MSG_NATIVE_RPC_REPLY);
+	rpc_reply_msg->refer_id = txn_id;
+	rpc_reply_msg->req_id = req_id;
+	rpc_reply_msg->code = MGMT_MSG_CODE_RPC_REPLY;
+	rpc_reply_msg->result_type = result_type;
+
+	if (output) {
+		darrp = mgmt_msg_native_get_darrp(rpc_reply_msg);
+		err = yang_print_tree_append(darrp, output, result_type,
+					     LYD_PRINT_SHRINK);
+		lyd_free_all(output);
+		if (err) {
+			ret = NB_ERR;
+			goto done;
+		}
+	}
+
+	(void)be_client_send_native_msg(client, rpc_reply_msg,
+					mgmt_msg_native_get_msg_len(
+						rpc_reply_msg),
+					false);
+done:
+	mgmt_msg_native_free_msg(rpc_reply_msg);
+	if (ret != NB_OK)
+		be_client_send_error(client, txn_id, req_id, false, -EINVAL,
+				     "Can't format RPC reply");
+}
+
+/*
+ * Process the RPC request.
+ */
+static void be_client_handle_rpc(struct mgmt_be_client *client, uint64_t txn_id,
+				 void *msgbuf, size_t msg_len)
+{
+	struct mgmt_msg_rpc *rpc_msg = msgbuf;
+	struct nb_node *nb_node;
+	struct lyd_node *input, *output;
+	const char *xpath;
+	const char *data;
+	char errmsg[BUFSIZ] = { 0 };
+	LY_ERR err;
+	int ret;
+
+	debug_be_client("Received RPC request for client %s txn-id %" PRIu64
+			" req-id %" PRIu64,
+			client->name, txn_id, rpc_msg->req_id);
+
+	xpath = mgmt_msg_native_xpath_data_decode(rpc_msg, msg_len, data);
+	if (!xpath) {
+		be_client_send_error(client, txn_id, rpc_msg->req_id, false,
+				     -EINVAL, "Corrupt RPC message");
+		return;
+	}
+
+	nb_node = nb_node_find(xpath);
+	if (!nb_node) {
+		be_client_send_error(client, txn_id, rpc_msg->req_id, false,
+				     -EINVAL, "No schema found for RPC: %s",
+				     xpath);
+		return;
+	}
+
+	if (!nb_node->cbs.rpc) {
+		be_client_send_error(client, txn_id, rpc_msg->req_id, false,
+				     -EINVAL, "No RPC callback for: %s", xpath);
+		return;
+	}
+
+	if (data) {
+		err = yang_parse_rpc(xpath, rpc_msg->request_type, data, false,
+				     &input);
+		if (err) {
+			be_client_send_error(client, txn_id, rpc_msg->req_id,
+					     false, -EINVAL,
+					     "Can't parse RPC data for: %s",
+					     xpath);
+			return;
+		}
+	} else {
+		/*
+		 * If there's no input data, create an empty input container.
+		 * It is especially needed for actions, because their parents
+		 * may hold necessary information.
+		 */
+		err = lyd_new_path2(NULL, ly_native_ctx, xpath, NULL, 0, 0, 0,
+				    NULL, &input);
+		if (err) {
+			be_client_send_error(client, txn_id, rpc_msg->req_id,
+					     false, -EINVAL,
+					     "Can't create input node for RPC: %s",
+					     xpath);
+			return;
+		}
+	}
+
+	err = lyd_new_path2(NULL, ly_native_ctx, xpath, NULL, 0, 0, 0, NULL,
+			    &output);
+	if (err) {
+		lyd_free_all(input);
+		be_client_send_error(client, txn_id, rpc_msg->req_id, false,
+				     -EINVAL,
+				     "Can't create output node for RPC: %s",
+				     xpath);
+		return;
+	}
+
+	ret = nb_callback_rpc(nb_node, xpath, input, output, errmsg,
+			      sizeof(errmsg));
+	if (ret != NB_OK) {
+		lyd_free_all(input);
+		lyd_free_all(output);
+		be_client_send_error(client, txn_id, rpc_msg->req_id, false,
+				     -EINVAL, "%s", errmsg);
+		return;
+	}
+
+	lyd_free_all(input);
+	if (!lyd_child(output)) {
+		lyd_free_all(output);
+		output = NULL;
+	}
+
+	be_client_send_rpc_reply(client, txn_id, rpc_msg->req_id,
+				 rpc_msg->request_type, output);
+}
+
 /*
  * Process the notification.
  */
@@ -975,6 +1112,9 @@ static void be_client_handle_native_msg(struct mgmt_be_client *client,
 	case MGMT_MSG_CODE_GET_TREE:
 		be_client_handle_get_tree(client, txn_id, msg, msg_len);
 		break;
+	case MGMT_MSG_CODE_RPC:
+		be_client_handle_rpc(client, txn_id, msg, msg_len);
+		break;
 	case MGMT_MSG_CODE_NOTIFY:
 		be_client_handle_notify(client, msg, msg_len);
 		break;
@@ -1040,6 +1180,9 @@ int mgmt_be_send_subscr_req(struct mgmt_be_client *client_ctx,
 	subscr_req.n_notif_xpaths = client_ctx->cbs.nnotif_xpaths;
 	subscr_req.notif_xpaths = (char **)client_ctx->cbs.notif_xpaths;
 
+	subscr_req.n_rpc_xpaths = client_ctx->cbs.nrpc_xpaths;
+	subscr_req.rpc_xpaths = (char **)client_ctx->cbs.rpc_xpaths;
+
 	mgmtd__be_message__init(&be_msg);
 	be_msg.message_case = MGMTD__BE_MESSAGE__MESSAGE_SUBSCR_REQ;
 	be_msg.subscr_req = &subscr_req;

lib/mgmt_be_client.h

@@ -75,6 +75,8 @@ struct mgmt_be_client_cbs {
 
 	const char **notif_xpaths;
 	uint nnotif_xpaths;
+	const char **rpc_xpaths;
+	uint nrpc_xpaths;
 };
 
 /***************************************************************

lib/mgmt_fe_client.c

@@ -360,6 +360,33 @@ int mgmt_fe_send_edit_req(struct mgmt_fe_client *client, uint64_t session_id,
 	return ret;
 }
 
+int mgmt_fe_send_rpc_req(struct mgmt_fe_client *client, uint64_t session_id,
+			 uint64_t req_id, LYD_FORMAT request_type,
+			 const char *xpath, const char *data)
+{
+	struct mgmt_msg_rpc *msg;
+	int ret;
+
+	msg = mgmt_msg_native_alloc_msg(struct mgmt_msg_rpc, 0,
+					MTYPE_MSG_NATIVE_RPC);
+	msg->refer_id = session_id;
+	msg->req_id = req_id;
+	msg->code = MGMT_MSG_CODE_RPC;
+	msg->request_type = request_type;
+
+	mgmt_msg_native_xpath_encode(msg, xpath);
+	if (data)
+		mgmt_msg_native_append(msg, data, strlen(data) + 1);
+
+	debug_fe_client("Sending RPC_REQ session-id %" PRIu64 " req-id %" PRIu64
+			" xpath: %s",
+			session_id, req_id, xpath);
+
+	ret = mgmt_msg_native_send_msg(&client->client.conn, msg, false);
+	mgmt_msg_native_free_msg(msg);
+	return ret;
+}
+
 static int mgmt_fe_client_handle_msg(struct mgmt_fe_client *client,
 				     Mgmtd__FeMessage *fe_msg)
 {
@@ -534,6 +561,7 @@ static void fe_client_handle_native_msg(struct mgmt_fe_client *client,
 	struct mgmt_msg_notify_data *notify_msg;
 	struct mgmt_msg_tree_data *tree_msg;
 	struct mgmt_msg_edit_reply *edit_msg;
+	struct mgmt_msg_rpc_reply *rpc_msg;
 	struct mgmt_msg_error *err_msg;
 	const char *xpath = NULL;
 	const char *data = NULL;
@@ -608,6 +636,23 @@ static void fe_client_handle_native_msg(struct mgmt_fe_client *client,
 						 session->user_ctx, msg->req_id,
 						 xpath);
 		break;
+	case MGMT_MSG_CODE_RPC_REPLY:
+		if (!session->client->cbs.rpc_notify)
+			return;
+
+		rpc_msg = (typeof(rpc_msg))msg;
+		if (msg_len < sizeof(*rpc_msg)) {
+			log_err_fe_client("Corrupt rpc-reply msg recv");
+			return;
+		}
+		dlen = msg_len - sizeof(*rpc_msg);
+
+		session->client->cbs.rpc_notify(client, client->user_data,
+						session->client_id,
+						msg->refer_id,
+						session->user_ctx, msg->req_id,
+						dlen ? rpc_msg->data : NULL);
+		break;
 	case MGMT_MSG_CODE_NOTIFY:
 		if (!session->client->cbs.async_notification)
 			return;

lib/mgmt_fe_client.h

@@ -120,6 +120,12 @@ struct mgmt_fe_client_cbs {
 			   uintptr_t session_ctx, uint64_t req_id,
 			   const char *xpath);
 
+	/* Called when RPC result is returned */
+	int (*rpc_notify)(struct mgmt_fe_client *client, uintptr_t user_data,
+			  uint64_t client_id, uint64_t session_id,
+			  uintptr_t session_ctx, uint64_t req_id,
+			  const char *result);
+
 	/* Called with asynchronous notifications from backends */
 	int (*async_notification)(struct mgmt_fe_client *client,
 				  uintptr_t user_data, uint64_t client_id,
@@ -454,6 +460,35 @@ extern int mgmt_fe_send_edit_req(struct mgmt_fe_client *client,
 				 uint8_t flags, uint8_t operation,
 				 const char *xpath, const char *data);
 
+/*
+ * Send RPC request to MGMTD daemon.
+ *
+ * client
+ *    Client object.
+ *
+ * session_id
+ *    Client session ID.
+ *
+ * req_id
+ *    Client request ID.
+ *
+ * result_type
+ *    The LYD_FORMAT of the result.
+ *
+ * xpath
+ *    the xpath of the RPC.
+ *
+ * data
+ *    the data tree.
+ *
+ * Returns:
+ *    0 on success, otherwise msg_conn_send_msg() return values.
+ */
+extern int mgmt_fe_send_rpc_req(struct mgmt_fe_client *client,
+				uint64_t session_id, uint64_t req_id,
+				LYD_FORMAT request_type, const char *xpath,
+				const char *data);
+
 /*
  * Destroy library and cleanup everything.
  */

lib/mgmt_msg_native.c

@@ -16,6 +16,8 @@ DEFINE_MTYPE(MSG_NATIVE, MSG_NATIVE_GET_DATA, "native get data msg");
 DEFINE_MTYPE(MSG_NATIVE, MSG_NATIVE_NOTIFY, "native get data msg");
 DEFINE_MTYPE(MSG_NATIVE, MSG_NATIVE_EDIT, "native edit msg");
 DEFINE_MTYPE(MSG_NATIVE, MSG_NATIVE_EDIT_REPLY, "native edit reply msg");
+DEFINE_MTYPE(MSG_NATIVE, MSG_NATIVE_RPC, "native RPC msg");
+DEFINE_MTYPE(MSG_NATIVE, MSG_NATIVE_RPC_REPLY, "native RPC reply msg");
 
 int vmgmt_msg_native_send_error(struct msg_conn *conn, uint64_t sess_or_txn_id,
 				uint64_t req_id, bool short_circuit_ok,

lib/mgmt_msg_native.h

@@ -152,6 +152,8 @@ DECLARE_MTYPE(MSG_NATIVE_GET_DATA);
 DECLARE_MTYPE(MSG_NATIVE_NOTIFY);
 DECLARE_MTYPE(MSG_NATIVE_EDIT);
 DECLARE_MTYPE(MSG_NATIVE_EDIT_REPLY);
+DECLARE_MTYPE(MSG_NATIVE_RPC);
+DECLARE_MTYPE(MSG_NATIVE_RPC_REPLY);
 
 /*
  * Native message codes
@@ -163,6 +165,8 @@ DECLARE_MTYPE(MSG_NATIVE_EDIT_REPLY);
 #define MGMT_MSG_CODE_NOTIFY	4
 #define MGMT_MSG_CODE_EDIT	 5
 #define MGMT_MSG_CODE_EDIT_REPLY 6
+#define MGMT_MSG_CODE_RPC	 7
+#define MGMT_MSG_CODE_RPC_REPLY	 8
 
 /*
  * Datastores
@@ -377,6 +381,42 @@ _Static_assert(sizeof(struct mgmt_msg_edit_reply) ==
 		       offsetof(struct mgmt_msg_edit_reply, data),
 	       "Size mismatch");
 
+/**
+ * struct mgmt_msg_rpc - RPC/action request.
+ *
+ * @request_type: ``LYD_FORMAT`` for the @data.
+ * @data: the xpath followed by the tree data for the operation.
+ */
+struct mgmt_msg_rpc {
+	struct mgmt_msg_header;
+	uint8_t request_type;
+	uint8_t resv2[7];
+
+	alignas(8) char data[];
+};
+
+_Static_assert(sizeof(struct mgmt_msg_rpc) ==
+		       offsetof(struct mgmt_msg_rpc, data),
+	       "Size mismatch");
+
+/**
+ * struct mgmt_msg_rpc_reply - RPC/action reply.
+ *
+ * @result_type: ``LYD_FORMAT`` for the @data.
+ * @data: the tree data for the reply.
+ */
+struct mgmt_msg_rpc_reply {
+	struct mgmt_msg_header;
+	uint8_t result_type;
+	uint8_t resv2[7];
+
+	alignas(8) char data[];
+};
+
+_Static_assert(sizeof(struct mgmt_msg_rpc_reply) ==
+		       offsetof(struct mgmt_msg_rpc_reply, data),
+	       "Size mismatch");
+
 /*
  * Validate that the message ends in a NUL terminating byte
  */
@@ -569,7 +609,10 @@ extern int vmgmt_msg_native_send_error(struct msg_conn *conn,
 		const char *__s = NULL;                                        \
 		if (msg->vsplit && msg->vsplit <= __len &&                     \
 		    msg->data[msg->vsplit - 1] == 0) {                         \
-			(__data) = msg->data + msg->vsplit;                    \
+			if (msg->vsplit < __len)                               \
+				(__data) = msg->data + msg->vsplit;            \
+			else                                                   \
+				(__data) = NULL;                               \
 			__s = msg->data;                                       \
 		}                                                              \
 		__s;                                                           \