rdataset.h

非常好的dns解析软件

/*
 * Copyright (C) 2004-2006  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1999-2003  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: rdataset.h,v 1.51.18.7 2006/03/03 00:56:53 marka Exp $ */

#ifndef DNS_RDATASET_H
#define DNS_RDATASET_H 1

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

/*! \file
 * \brief
 * A DNS rdataset is a handle that can be associated with a collection of
 * rdata all having a common owner name, class, and type.
 *
 * The dns_rdataset_t type is like a "virtual class".  To actually use
 * rdatasets, an implementation of the method suite (e.g. "slabbed rdata") is
 * required.
 *
 * XXX <more> XXX
 *
 * MP:
 *\li	Clients of this module must impose any required synchronization.
 *
 * Reliability:
 *\li	No anticipated impact.
 *
 * Resources:
 *\li	TBS
 *
 * Security:
 *\li	No anticipated impact.
 *
 * Standards:
 *\li	None.
 */

#include <isc/lang.h>
#include <isc/magic.h>
#include <isc/stdtime.h>

#include <dns/types.h>

ISC_LANG_BEGINDECLS

typedef enum {
	dns_rdatasetadditional_fromauth,
	dns_rdatasetadditional_fromcache,
	dns_rdatasetadditional_fromglue
} dns_rdatasetadditional_t;

typedef struct dns_rdatasetmethods {
	void			(*disassociate)(dns_rdataset_t *rdataset);
	isc_result_t		(*first)(dns_rdataset_t *rdataset);
	isc_result_t		(*next)(dns_rdataset_t *rdataset);
	void			(*current)(dns_rdataset_t *rdataset,
					   dns_rdata_t *rdata);
	void			(*clone)(dns_rdataset_t *source,
					 dns_rdataset_t *target);
	unsigned int		(*count)(dns_rdataset_t *rdataset);
	isc_result_t		(*addnoqname)(dns_rdataset_t *rdataset,
					      dns_name_t *name);
	isc_result_t		(*getnoqname)(dns_rdataset_t *rdataset,
					      dns_name_t *name,
					      dns_rdataset_t *nsec,
					      dns_rdataset_t *nsecsig);
	isc_result_t		(*getadditional)(dns_rdataset_t *rdataset,
						 dns_rdatasetadditional_t type,
						 dns_rdatatype_t qtype,
						 dns_acache_t *acache,
						 dns_zone_t **zonep,
						 dns_db_t **dbp,
						 dns_dbversion_t **versionp,
						 dns_dbnode_t **nodep,
						 dns_name_t *fname,
						 dns_message_t *msg,
						 isc_stdtime_t now);
	isc_result_t		(*setadditional)(dns_rdataset_t *rdataset,
						 dns_rdatasetadditional_t type,
						 dns_rdatatype_t qtype,
						 dns_acache_t *acache,
						 dns_zone_t *zone,
						 dns_db_t *db,
						 dns_dbversion_t *version,
						 dns_dbnode_t *node,
						 dns_name_t *fname);
	isc_result_t		(*putadditional)(dns_acache_t *acache,
						 dns_rdataset_t *rdataset,
						 dns_rdatasetadditional_t type,
						 dns_rdatatype_t qtype);
} dns_rdatasetmethods_t;

#define DNS_RDATASET_MAGIC	       ISC_MAGIC('D','N','S','R')
#define DNS_RDATASET_VALID(set)	       ISC_MAGIC_VALID(set, DNS_RDATASET_MAGIC)

/*%
 * Direct use of this structure by clients is strongly discouraged, except
 * for the 'link' field which may be used however the client wishes.  The
 * 'private', 'current', and 'index' fields MUST NOT be changed by clients.
 * rdataset implementations may change any of the fields.
 */
struct dns_rdataset {
	unsigned int			magic;		/* XXX ? */
	dns_rdatasetmethods_t *		methods;
	ISC_LINK(dns_rdataset_t)	link;
	/*
	 * XXX do we need these, or should they be retrieved by methods?
	 * Leaning towards the latter, since they are not frequently required
	 * once you have the rdataset.
	 */
	dns_rdataclass_t		rdclass;
	dns_rdatatype_t			type;
	dns_ttl_t			ttl;
	dns_trust_t			trust;
	dns_rdatatype_t			covers;
	/*
	 * attributes
	 */
	unsigned int			attributes;
	/*%
	 * the counter provides the starting point in the "cyclic" order.
	 * The value ISC_UINT32_MAX has a special meaning of "picking up a
	 * random value." in order to take care of databases that do not
	 * increment the counter.
	 */
	isc_uint32_t			count;
	/*@{*/
	/*%
	 * These are for use by the rdataset implementation, and MUST NOT
	 * be changed by clients.
	 */
	void *				private1;
	void *				private2;
	void *				private3;
	unsigned int			privateuint4;
	void *				private5;
	void *				private6;
	/*@}*/
};

/*!
 * \def DNS_RDATASETATTR_RENDERED
 *	Used by message.c to indicate that the rdataset was rendered.
 *
 * \def DNS_RDATASETATTR_TTLADJUSTED
 *	Used by message.c to indicate that the rdataset's rdata had differing
 *	TTL values, and the rdataset->ttl holds the smallest.
 *
 * \def DNS_RDATASETATTR_LOADORDER
 *	Output the RRset in load order.
 */

#define DNS_RDATASETATTR_QUESTION	0x00000001
#define DNS_RDATASETATTR_RENDERED	0x00000002	/*%< Used by message.c */
#define DNS_RDATASETATTR_ANSWERED	0x00000004	/*%< Used by server. */
#define DNS_RDATASETATTR_CACHE		0x00000008	/*%< Used by resolver. */
#define DNS_RDATASETATTR_ANSWER		0x00000010	/*%< Used by resolver. */
#define DNS_RDATASETATTR_ANSWERSIG	0x00000020	/*%< Used by resolver. */
#define DNS_RDATASETATTR_EXTERNAL	0x00000040	/*%< Used by resolver. */
#define DNS_RDATASETATTR_NCACHE		0x00000080	/*%< Used by resolver. */
#define DNS_RDATASETATTR_CHAINING	0x00000100	/*%< Used by resolver. */
#define DNS_RDATASETATTR_TTLADJUSTED	0x00000200	/*%< Used by message.c */
#define DNS_RDATASETATTR_FIXEDORDER	0x00000400
#define DNS_RDATASETATTR_RANDOMIZE	0x00000800
#define DNS_RDATASETATTR_CHASE		0x00001000	/*%< Used by resolver. */
#define DNS_RDATASETATTR_NXDOMAIN	0x00002000
#define DNS_RDATASETATTR_NOQNAME	0x00004000
#define DNS_RDATASETATTR_CHECKNAMES	0x00008000	/*%< Used by resolver. */
#define DNS_RDATASETATTR_REQUIREDGLUE	0x00010000
#define DNS_RDATASETATTR_LOADORDER	0x00020000

/*%
 * _OMITDNSSEC:
 * 	Omit DNSSEC records when rendering ncache records.
 */
#define DNS_RDATASETTOWIRE_OMITDNSSEC	0x0001

void
dns_rdataset_init(dns_rdataset_t *rdataset);
/*%<
 * Make 'rdataset' a valid, disassociated rdataset.
 *
 * Requires:
 *\li	'rdataset' is not NULL.
 *
 * Ensures:
 *\li	'rdataset' is a valid, disassociated rdataset.
 */

void
dns_rdataset_invalidate(dns_rdataset_t *rdataset);
/*%<
 * Invalidate 'rdataset'.
 *
 * Requires:
 *\li	'rdataset' is a valid, disassociated rdataset.
 *
 * Ensures:
 *\li	If assertion checking is enabled, future attempts to use 'rdataset'
 *	without initializing it will cause an assertion failure.
 */

void
dns_rdataset_disassociate(dns_rdataset_t *rdataset);
/*%<
 * Disassociate 'rdataset' from its rdata, allowing it to be reused.
 *
 * Notes:
 *\li	The client must ensure it has no references to rdata in the rdataset
 *	before disassociating.
 *
 * Requires:
 *\li	'rdataset' is a valid, associated rdataset.
 *
 * Ensures:
 *\li	'rdataset' is a valid, disassociated rdataset.
 */

isc_boolean_t
dns_rdataset_isassociated(dns_rdataset_t *rdataset);
/*%<
 * Is 'rdataset' associated?
 *
 * Requires:
 *\li	'rdataset' is a valid rdataset.
 *
 * Returns:
 *\li	#ISC_TRUE			'rdataset' is associated.
 *\li	#ISC_FALSE			'rdataset' is not associated.
 */

void
dns_rdataset_makequestion(dns_rdataset_t *rdataset, dns_rdataclass_t rdclass,
			  dns_rdatatype_t type);
/*%<
 * Make 'rdataset' a valid, associated, question rdataset, with a
 * question class of 'rdclass' and type 'type'.
 *
 * Notes:
 *\li	Question rdatasets have a class and type, but no rdata.
 *
 * Requires:
 *\li	'rdataset' is a valid, disassociated rdataset.
 *
 * Ensures:
 *\li	'rdataset' is a valid, associated, question rdataset.
 */

void
dns_rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target);
/*%<
 * Make 'target' refer to the same rdataset as 'source'.
 *
 * Requires:
 *\li	'source' is a valid, associated rdataset.
 *
 *\li	'target' is a valid, dissociated rdataset.
 *
 * Ensures:
 *\li	'target' references the same rdataset as 'source'.
 */

unsigned int
dns_rdataset_count(dns_rdataset_t *rdataset);
/*%<
 * Return the number of records in 'rdataset'.
 *
 * Requires:
 *\li	'rdataset' is a valid, associated rdataset.
 *
 * Returns:
 *\li	The number of records in 'rdataset'.
 */

isc_result_t
dns_rdataset_first(dns_rdataset_t *rdataset);
/*%<
 * Move the rdata cursor to the first rdata in the rdataset (if any).
 *
 * Requires:
 *\li	'rdataset' is a valid, associated rdataset.
 *
 * Returns: