lib: reorg native message header

Signed-off-by: Christian Hopps <[email protected]>

lib/mgmt_be_client.c

@@ -799,7 +799,7 @@ static enum nb_error be_client_send_tree_data_batch(const struct lyd_node *tree,
 
 	darr_append_nz(buf, offsetof(typeof(*tree_msg), result));
 	tree_msg = (typeof(tree_msg))buf;
-	tree_msg->txn_id = args->txn_id;
+	tree_msg->refer_id = args->txn_id;
 	tree_msg->req_id = args->req_id;
 	tree_msg->code = MGMT_MSG_CODE_TREE_DATA;
 	tree_msg->result_type = args->result_type;
@@ -848,7 +848,7 @@ static void be_client_handle_get_tree(struct mgmt_be_client *client,
 
 	args = XMALLOC(MTYPE_MGMTD_BE_GT_CB_ARGS, sizeof(*args));
 	args->client = client;
-	args->txn_id = get_tree_msg->txn_id;
+	args->txn_id = get_tree_msg->refer_id;
 	args->req_id = get_tree_msg->req_id;
 	args->result_type = get_tree_msg->result_type;
 	nb_op_walk(get_tree_msg->xpath, NULL, 0, true, NULL, NULL,
@@ -864,7 +864,7 @@ static void be_client_handle_native_msg(struct mgmt_be_client *client,
 					struct mgmt_msg_header *msg,
 					size_t msg_len)
 {
-	uint64_t txn_id = msg->txn_id;
+	uint64_t txn_id = msg->refer_id;
 
 	switch (msg->code) {
 	case MGMT_MSG_CODE_GET_TREE:
@@ -875,7 +875,7 @@ static void be_client_handle_native_msg(struct mgmt_be_client *client,
 				    " req-id %" PRIu64 " code %u to client %s",
 				    txn_id, msg->req_id, msg->code,
 				    client->name);
-		be_client_send_error(client, msg->txn_id, msg->req_id, false, -1,
+		be_client_send_error(client, msg->refer_id, msg->req_id, false, -1,
 				     "BE cilent %s recv msg unknown txn-id %" PRIu64,
 				     client->name, txn_id);
 		break;

lib/mgmt_fe_client.c

@@ -325,7 +325,7 @@ int mgmt_fe_send_get_tree_req(struct mgmt_fe_client *client,
 	int ret;
 
 	msg = XCALLOC(MTYPE_MGMTD_FE_GET_DATA_MSG, mlen);
-	msg->session_id = session_id;
+	msg->refer_id = session_id;
 	msg->req_id = req_id;
 	msg->code = MGMT_MSG_CODE_GET_TREE;
 	msg->result_type = result_type;
@@ -518,13 +518,13 @@ static void fe_client_handle_native_msg(struct mgmt_fe_client *client,
 	struct mgmt_msg_error *err_msg;
 
 	MGMTD_FE_CLIENT_DBG("Got GET_TREE reply for session-id %" PRIu64,
-			    msg->session_id);
+			    msg->refer_id);
 
-	session = mgmt_fe_find_session_by_session_id(client, msg->session_id);
+	session = mgmt_fe_find_session_by_session_id(client, msg->refer_id);
 
 	if (!session || !session->client) {
 		MGMTD_FE_CLIENT_ERR("No session for received native msg session-id %" PRIu64,
-				    msg->session_id);
+				    msg->refer_id);
 		return;
 	}
 
@@ -536,7 +536,7 @@ static void fe_client_handle_native_msg(struct mgmt_fe_client *client,
 		err_msg = (typeof(err_msg))msg;
 		session->client->cbs.error_notify(client, client->user_data,
 						  session->client_id,
-						  msg->session_id,
+						  msg->refer_id,
 						  session->user_ctx,
 						  msg->req_id, err_msg->error,
 						  err_msg->errstr);
@@ -548,7 +548,7 @@ static void fe_client_handle_native_msg(struct mgmt_fe_client *client,
 		tree_msg = (typeof(tree_msg))msg;
 		session->client->cbs.get_tree_notify(client, client->user_data,
 						     session->client_id,
-						     msg->session_id,
+						     msg->refer_id,
 						     session->user_ctx,
 						     msg->req_id,
 						     MGMTD_DS_OPERATIONAL,
@@ -560,7 +560,7 @@ static void fe_client_handle_native_msg(struct mgmt_fe_client *client,
 	default:
 		MGMTD_FE_CLIENT_ERR("unknown native message session-id %" PRIu64
 				    " req-id %" PRIu64 " code %u",
-				    msg->session_id, msg->req_id, msg->code);
+				    msg->refer_id, msg->req_id, msg->code);
 		break;
 	}
 }

lib/mgmt_msg.c

@@ -348,7 +348,7 @@ int mgmt_msg_send_msg(struct mgmt_msg_state *ms, uint8_t version, void *msg,
 		MGMT_MSG_DBG(
 			dbgtag,
 			"Sending native msg sess/txn-id %"PRIu64" req-id %"PRIu64" code %u",
-			native_msg->session_id, native_msg->req_id, native_msg->code);
+			native_msg->refer_id, native_msg->req_id, native_msg->code);
 
 	}
 

lib/mgmt_msg_native.c

@@ -22,7 +22,7 @@ int vmgmt_msg_native_send_error(struct msg_conn *conn, uint64_t sess_or_txn_id,
 	int ret;
 
 	msg = XMALLOC(MTYPE_MSG_NATIVE_ERROR, 1024);
-	msg->session_id = sess_or_txn_id;
+	msg->refer_id = sess_or_txn_id;
 	msg->req_id = req_id;
 	msg->code = MGMT_MSG_CODE_ERROR;
 	msg->error = error;

lib/mgmt_msg_native.h

@@ -26,58 +26,105 @@ extern "C" {
 DECLARE_MTYPE(MSG_NATIVE_MSG);
 DECLARE_MTYPE(MSG_NATIVE_ERROR);
 
+/*
+ * Adding New Messages Types
+ * -------------------------
+ *
+ * Native messages structs have 2 simple rules:
+ *
+ * 1) All fields should be naturally aligned.
+ * 2) Any required padding should be explicitly reserved.
+ *
+ * This is so for all intents and purposes the messages may be read and written
+ * direct from "the wire", easily, using common programming languages (e.g.,
+ * C, rust, go, python, ...)
+ *
+ * Additionally by design fixed fields precede the variable length data which
+ * comes at the end. The zero length arrays fields are aligned such that this is so:
+ *
+ *    sizeof(struct mgmt_msg_foo) == offsetof(struct mgmt_msg_foo, field)
+ *
+ * This allows things like `value = (HDR + 1)` to work.
+ */
+
 /*
  * Native message codes
  */
 #define MGMT_MSG_CODE_ERROR	0
 #define MGMT_MSG_CODE_GET_TREE	1
 #define MGMT_MSG_CODE_TREE_DATA 2
 
-/*
- * A note on alignments: The zero length arrays fields are aligned such that
- * this is so:
- *
- *    sizeof(struct mgmt_msg_foo) == offsetof(struct mgmt_msg_foo, field)
+/**
+ * struct mgmt_msg_header - Header common to all native messages.
  *
- * This allows things like `ptr = darr_append_n(A, sizeof(*ptr))`
- * to work
+ * @code: the actual type of the message.
+ * @resv: Set to zero, ignore on receive.
+ * @vsplit: If a variable section is split in 2, the length of first part.
+ * @refer_id: the session, txn, conn, etc, this message is associated with.
+ * @req_id: the request this message is for.
  */
-
-
 struct mgmt_msg_header {
-	union {
-		uint64_t session_id;
-		uint64_t txn_id;
-	};
-	uint64_t req_id;
 	uint16_t code;
+	uint16_t resv;
+	uint32_t vsplit;
+	uint64_t refer_id;
+	uint64_t req_id;
 };
+_Static_assert(sizeof(struct mgmt_msg_header) == 3 * 8, "Bad padding");
+_Static_assert(sizeof(struct mgmt_msg_header) ==
+		       offsetof(struct mgmt_msg_header, req_id) +
+			       sizeof(((struct mgmt_msg_header *)0)->req_id),
+	       "Size mismatch");
 
+/**
+ * struct mgmt_msg_error - Common error message.
+ * @error: An error value.
+ * @errst: Description of error can be 0 length.
+ *
+ * This common error message can be used for replies for many msg requests
+ * (req_id).
+ */
 struct mgmt_msg_error {
 	struct mgmt_msg_header;
 	int16_t error;
+	uint8_t resv2[6];
 
 	alignas(8) char errstr[];
 };
 _Static_assert(sizeof(struct mgmt_msg_error) ==
 		       offsetof(struct mgmt_msg_error, errstr),
 	       "Size mismatch");
 
+/**
+ * struct mgmt_msg_get_tree - Message carrying xpath query request.
+ * @result_type: ``LYD_FORMAT`` for the returned result.
+ * @xpath: the query for the data to return.
+ */
 struct mgmt_msg_get_tree {
 	struct mgmt_msg_header;
 	uint8_t result_type;
+	uint8_t resv2[7];
 
 	alignas(8) char xpath[];
 };
 _Static_assert(sizeof(struct mgmt_msg_get_tree) ==
 		       offsetof(struct mgmt_msg_get_tree, xpath),
 	       "Size mismatch");
 
+/**
+ * struct mgmt_msg_tree_data - Message carrying tree data.
+ * @partial_error: If the full result could not be returned do to this error.
+ * @result_type: ``LYD_FORMAT`` for format of the @result value.
+ * @more: if this is a partial return and there will be more coming.
+ * @result: The tree data in @result_type format.
+ *
+ */
 struct mgmt_msg_tree_data {
 	struct mgmt_msg_header;
 	int8_t partial_error;
 	uint8_t result_type;
 	uint8_t more;
+	uint8_t resv2[5];
 
 	alignas(8) uint8_t result[];
 };

mgmtd/mgmt_be_adapter.c

@@ -540,18 +540,18 @@ static void be_adapter_handle_native_msg(struct mgmt_be_client_adapter *adapter,
 	case MGMT_MSG_CODE_ERROR:
 		error_msg = (typeof(error_msg))msg;
 		MGMTD_BE_ADAPTER_DBG("Got ERROR from '%s' txn-id %" PRIx64,
-				     adapter->name, msg->txn_id);
+				     adapter->name, msg->refer_id);
 
 		/* Forward the reply to the txn module */
-		mgmt_txn_notify_error(adapter, msg->txn_id, msg->req_id,
+		mgmt_txn_notify_error(adapter, msg->refer_id, msg->req_id,
 				      error_msg->error, error_msg->errstr);
 
 		break;
 	case MGMT_MSG_CODE_TREE_DATA:
 		/* tree data from a backend client */
 		tree_msg = (typeof(tree_msg))msg;
 		MGMTD_BE_ADAPTER_DBG("Got TREE_DATA from '%s' txn-id %" PRIx64,
-				     adapter->name, msg->txn_id);
+				     adapter->name, msg->refer_id);
 
 		/* Forward the reply to the txn module */
 		mgmt_txn_notify_tree_data_reply(adapter, tree_msg, msg_len);
@@ -560,7 +560,7 @@ static void be_adapter_handle_native_msg(struct mgmt_be_client_adapter *adapter,
 		MGMTD_BE_ADAPTER_ERR("unknown native message txn-id %" PRIu64
 				     " req-id %" PRIu64
 				     " code %u from BE client for adapter %s",
-				     msg->txn_id, msg->req_id, msg->code,
+				     msg->refer_id, msg->req_id, msg->code,
 				     adapter->name);
 		break;
 	}

mgmtd/mgmt_fe_adapter.c

@@ -1089,7 +1089,7 @@ static int fe_adapter_send_tree_data(struct mgmt_fe_session_ctx *session,
 
 	darr_append_n(buf, offsetof(typeof(*msg), result));
 	msg = (typeof(msg))buf;
-	msg->session_id = session->session_id;
+	msg->refer_id = session->session_id;
 	msg->req_id = req_id;
 	msg->code = MGMT_MSG_CODE_TREE_DATA;
 	msg->partial_error = partial_error;
@@ -1200,10 +1200,10 @@ static void fe_adapter_handle_native_msg(struct mgmt_fe_client_adapter *adapter,
 {
 	struct mgmt_fe_session_ctx *session;
 
-	session = mgmt_session_id2ctx(msg->session_id);
+	session = mgmt_session_id2ctx(msg->refer_id);
 	if (!session) {
 		MGMTD_FE_ADAPTER_ERR("adapter %s: recv msg unknown session-id %" PRIu64,
-				     adapter->name, msg->session_id);
+				     adapter->name, msg->refer_id);
 		return;
 	}
 	assert(session->adapter == adapter);
@@ -1216,7 +1216,7 @@ static void fe_adapter_handle_native_msg(struct mgmt_fe_client_adapter *adapter,
 		MGMTD_FE_ADAPTER_ERR("unknown native message session-id %" PRIu64
 				     " req-id %" PRIu64
 				     " code %u to FE adapter %s",
-				     msg->session_id, msg->req_id, msg->code,
+				     msg->refer_id, msg->req_id, msg->code,
 				     adapter->name);
 		break;
 	}

mgmtd/mgmt_txn.c

@@ -2381,7 +2381,7 @@ int mgmt_txn_send_get_tree_oper(uint64_t txn_id, uint64_t req_id,
 	get_tree->xpath = XSTRDUP(MTYPE_MGMTD_XPATH, xpath);
 
 	msg = XCALLOC(MTYPE_MSG_NATIVE_MSG, mlen);
-	msg->txn_id = txn_id;
+	msg->refer_id = txn_id;
 	msg->req_id = req_id;
 	msg->code = MGMT_MSG_CODE_GET_TREE;
 	/* Always operate with the binary format in the backend */
@@ -2479,7 +2479,7 @@ int mgmt_txn_notify_tree_data_reply(struct mgmt_be_client_adapter *adapter,
 				    struct mgmt_msg_tree_data *data_msg,
 				    size_t msg_len)
 {
-	uint64_t txn_id = data_msg->txn_id;
+	uint64_t txn_id = data_msg->refer_id;
 	uint64_t req_id = data_msg->req_id;
 
 	enum mgmt_be_client_id id = adapter->id;