isa0061/input0
  +   	ˆl–äY>”ªh¥8 …q·®4ê˜´oÂ„Z_†I|¥+ÂÁ ?÷     	/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

#ifndef DNS_RDATA_H
#define DNS_RDATA_H 1

/*****
 ***** Module Info
 *****/

/*! \file dns/rdata.h
 * \brief
 * Provides facilities for manipulating DNS rdata, including conversions to
 * and from wire format and text format.
 *
 * Given the large amount of rdata possible in a nameserver, it was important
 * to come up with a very efficient way of storing rdata, but at the same
 * time allow it to be manipulated.
 *
 * The decision was to store rdata in uncompressed wire format,
 * and not to make it a fully abstracted object; i.e. certain parts of the
 * server know rdata is stored that way.  This saves a lot of memory, and
 * makes adding rdata to messages easy.  Having much of the server know
 * the representation would be perilous, and we certainly don't want each
 * user of rdata to be manipulating such a low-level structure.  This is
 * where the rdata module comes in.  The module allows rdata handles to be
 * created and attached to uncompressed wire format regions.  All rdata
 * operations and conversions are done through these handles.
 *
 * Implementation Notes:
 *
 *\li	The routines in this module are expected to be synthesized by the
 *	build process from a set of source files, one per rdata type.  For
 *	portability, it's probably best that the building be done by a C
 *	program.  Adding a new rdata type will be a simple matter of adding
 *	a file to a directory and rebuilding the server.  *All* knowledge of
 *	the format of a particular rdata type is in this file.
 *
 * MP:
 *\li	Clients of this module must impose any required synchronization.
 *
 * Reliability:
 *\li	This module deals with low-level byte streams.  Errors in any of
 *	the functions are likely to crash the server or corrupt memory.
 *
 *\li	Rdata is typed, and the caller must know what type of rdata it has.
 *	A caller that gets this wrong could crash the server.
 *
 *\li	The fromstruct() and tostruct() routines use a void * pointer to
 *	represent the structure.  The caller must ensure that it passes a
 *	pointer to the appropriate type, or the server could crash or memory
 *	could be corrupted.
 *
 * Resources:
 *\li	None.
 *
 * Security:
 *
 *\li	*** WARNING ***
 *	dns_rdata_fromwire() deals with raw network data.  An error in
 *	this routine could result in the failure or hijacking of the server.
 *
 * Standards:
 *\li	RFC1035
 *\li	Draft EDNS0 (0)
 *\li	Draft EDNS1 (0)
 *\li	Draft Binary Labels (2)
 *\li	Draft Local Compression (1)
 *\li	Various RFCs for particular types; these will be documented in the
 *	 sources files of the types.
 *
 */

/***
 *** Imports
 ***/

#include <isc/lang.h>

#include <dns/types.h>
#include <dns/name.h>
#include <dns/message.h>

ISC_LANG_BEGINDECLS


/***
 *** Types
 ***/

/*%
 ***** An 'rdata' is a handle to a binary region.  The handle has an RR
 ***** class and type, and the data in the binary region is in the format
 ***** of the given class and type.
 *****/
/*%
 * Clients are strongly discouraged from using this type directly, with
 * the exception of the 'link' field which may be used directly for whatever
 * purpose the client desires.
 */
struct dns_rdata {
	unsigned char *			data;
	unsigned int			length;
	dns_rdataclass_t		rdclass;
	dns_rdatatype_t			type;
	unsigned int			flags;
	ISC_LINK(dns_rdata_t)		link;
};

#define DNS_RDATA_INIT { NULL, 0, 0, 0, 0, {(void*)(-1), (void *)(-1)}}

#define DNS_RDATA_CHECKINITIALIZED
#ifdef DNS_RDATA_CHECKINITIALIZED
#define DNS_RDATA_INITIALIZED(rdata) \
	((rdata)->data == NULL && (rdata)->length == 0 && \
	 (rdata)->rdclass == 0 && (rdata)->type == 0 && (rdata)->flags == 0 && \
	 !ISC_LINK_LINKED((rdata