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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-marshal-header.h Managing marshaling/demarshaling of message headers
*
* Copyright (C) 2005 Red Hat, Inc.
*
* SPDX-License-Identifier: AFL-2.1 OR GPL-2.0-or-later
*
* Licensed under the Academic Free License version 2.1
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#ifndef DBUS_MARSHAL_HEADER_H
#define DBUS_MARSHAL_HEADER_H
#include <dbus/dbus-marshal-basic.h>
#include <dbus/dbus-marshal-validate.h>
typedef struct DBusHeader DBusHeader;
typedef struct DBusHeaderField DBusHeaderField;
#define _DBUS_HEADER_FIELD_VALUE_UNKNOWN -1
#define _DBUS_HEADER_FIELD_VALUE_NONEXISTENT -2
/**
* Cached information about a header field in the message
*/
struct DBusHeaderField
{
int value_pos; /**< Position of field value, or -1/-2 */
};
/**
* Message header data and some cached details of it.
*
* A message looks like this:
*
* @code
* | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | <- index % 8
* |-------|-------|-------|------|-----|-----|-----|-----|
* | Order | Type | Flags | Vers | Body length |
* | Serial | Fields array length [A]
* [A] Code |Sig.len| Signature + \0 | Content...| <- first field
* | Content ... | Pad to 8-byte boundary|
* | Code |Sig.len| Signature + \0 | Content... | <- second field
* ...
* | Code |Sig.len| Signature | Content... | <- last field
* | Content ... [B] Padding to 8-byte boundary [C]
* [C] Body ... |
* ...
* | Body ... [D] <- no padding after natural length
* @endcode
*
* Each field is a struct<byte,variant>. All structs have 8-byte alignment,
* so each field is preceded by 0-7 bytes of padding to an 8-byte boundary
* (for the first field it happens to be 0 bytes). The overall header
* is followed by 0-7 bytes of padding to align the body.
*
* Key to content, with variable name references for _dbus_header_load():
*
* Order: byte order, currently 'l' or 'B' (byte_order)
* Type: message type such as DBUS_MESSAGE_TYPE_METHOD_CALL
* Flags: message flags such as DBUS_HEADER_FLAG_NO_REPLY_EXPECTED
* Vers: D-Bus wire protocol version, currently always 1
* Body length: Distance from [C] to [D]
* Serial: Message serial number
* Fields array length: Distance from [A] to [B] (fields_array_len)
*
* To understand _dbus_header_load():
*
* [A] is FIRST_FIELD_OFFSET.
* header_len is from 0 to [C].
* padding_start is [B].
* padding_len is the padding from [B] to [C].
*/
struct DBusHeader
{
DBusString data; /**< Header network data, stored
* separately from body so we can
* independently realloc it. Its length includes
* up to 8 bytes of padding to align the body to
* an 8-byte boundary.
*
* In a steady state, this has length [C]. During
* editing, it is temporarily extended to have the
* maximum possible padding.
*/
DBusHeaderField fields[DBUS_HEADER_FIELD_LAST + 1]; /**< Track the location
* of each field in header
*/
dbus_uint32_t padding : 3; /**< 0-7 bytes of alignment in header,
the distance from [B] to [C] */
dbus_uint32_t byte_order : 8; /**< byte order of header (must always
match the content of byte 0) */
};
dbus_bool_t _dbus_header_init (DBusHeader *header);
void _dbus_header_free (DBusHeader *header);
void _dbus_header_reinit (DBusHeader *header);
dbus_bool_t _dbus_header_create (DBusHeader *header,
int byte_order,
int type,
const char *destination,
const char *path,
const char *interface,
const char *member,
const char *error_name);
dbus_bool_t _dbus_header_copy (const DBusHeader *header,
DBusHeader *dest);
int _dbus_header_get_message_type (DBusHeader *header);
void _dbus_header_set_serial (DBusHeader *header,
dbus_uint32_t serial);
dbus_uint32_t _dbus_header_get_serial (DBusHeader *header);
void _dbus_header_update_lengths (DBusHeader *header,
int body_len);
DBUS_PRIVATE_EXPORT
dbus_bool_t _dbus_header_set_field_basic (DBusHeader *header,
int field,
int type,
const void *value);
dbus_bool_t _dbus_header_get_field_basic (DBusHeader *header,
int field,
int type,
void *value);
DBUS_PRIVATE_EXPORT
dbus_bool_t _dbus_header_get_field_raw (DBusHeader *header,
int field,
const DBusString **str,
int *pos);
DBUS_PRIVATE_EXPORT
dbus_bool_t _dbus_header_delete_field (DBusHeader *header,
int field);
void _dbus_header_toggle_flag (DBusHeader *header,
dbus_uint32_t flag,
dbus_bool_t value);
dbus_bool_t _dbus_header_get_flag (DBusHeader *header,
dbus_uint32_t flag);
dbus_bool_t _dbus_header_ensure_signature (DBusHeader *header,
DBusString **type_str,
int *type_pos);
dbus_bool_t _dbus_header_have_message_untrusted (int max_message_length,
DBusValidity *validity,
int *byte_order,
int *fields_array_len,
int *header_len,
int *body_len,
const DBusString *str,
int start,
int len);
dbus_bool_t _dbus_header_load (DBusHeader *header,
DBusValidationMode mode,
DBusValidity *validity,
int byte_order,
int fields_array_len,
int header_len,
int body_len,
const DBusString *str);
void _dbus_header_byteswap (DBusHeader *header,
int new_order);
DBUS_PRIVATE_EXPORT
char _dbus_header_get_byte_order (const DBusHeader *header);
dbus_bool_t _dbus_header_remove_unknown_fields (DBusHeader *header);
#endif /* DBUS_MARSHAL_HEADER_H */
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