diff.h

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/*
 * Copyright (C) 2004-2010, 2013  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000, 2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or 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: diff.h,v 1.19 2010/06/04 23:51:14 tbox Exp $ */

#ifndef DNS_DIFF_H
#define DNS_DIFF_H 1

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

/*! \file dns/diff.h
 * \brief
 * A diff is a convenience type representing a list of changes to be
 * made to a database.
 */

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

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

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

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

/*%
 * A dns_difftuple_t represents a single RR being added or deleted.
 * The RR type and class are in the 'rdata' member; the class is always
 * the real one, not a DynDNS meta-class, so that the rdatas can be
 * compared using dns_rdata_compare().  The TTL is significant
 * even for deletions, because a deletion/addition pair cannot
 * be canceled out if the TTL differs (it might be an explicit
 * TTL update).
 *
 * Tuples are also used to represent complete RRs with owner
 * names for a couple of other purposes, such as the
 * individual RRs of a "RRset exists (value dependent)"
 * prerequisite set.  In this case, op==DNS_DIFFOP_EXISTS,
 * and the TTL is ignored.
 *
 * DNS_DIFFOP_*RESIGN will cause the 'resign' attribute of the resulting
 * RRset to be recomputed to be 'resign' seconds before the earliest RRSIG
 * timeexpire.
 */

typedef enum {
        DNS_DIFFOP_ADD = 0,             /*%< Add an RR. */
        DNS_DIFFOP_DEL = 1,             /*%< Delete an RR. */
        DNS_DIFFOP_EXISTS = 2,          /*%< Assert RR existence. */
        DNS_DIFFOP_ADDRESIGN = 4,       /*%< ADD + RESIGN. */
        DNS_DIFFOP_DELRESIGN = 5        /*%< DEL + RESIGN. */
} dns_diffop_t;

typedef struct dns_difftuple dns_difftuple_t;

#define DNS_DIFFTUPLE_MAGIC     ISC_MAGIC('D','I','F','T')
#define DNS_DIFFTUPLE_VALID(t)  ISC_MAGIC_VALID(t, DNS_DIFFTUPLE_MAGIC)

struct dns_difftuple {
        unsigned int                    magic;
        isc_mem_t                       *mctx;
        dns_diffop_t                    op;
        dns_name_t                      name;
        dns_ttl_t                       ttl;
        dns_rdata_t                     rdata;
        ISC_LINK(dns_difftuple_t)       link;
        /* Variable-size name data and rdata follows. */
};

/*%
 * A dns_diff_t represents a set of changes being applied to
 * a zone.  Diffs are also used to represent "RRset exists
 * (value dependent)" prerequisites.
 */
typedef struct dns_diff dns_diff_t;

#define DNS_DIFF_MAGIC          ISC_MAGIC('D','I','F','F')
#define DNS_DIFF_VALID(t)       ISC_MAGIC_VALID(t, DNS_DIFF_MAGIC)

struct dns_diff {
        unsigned int                    magic;
        isc_mem_t *                     mctx;
        ISC_LIST(dns_difftuple_t)       tuples;
};

/* Type of comparison function for sorting diffs. */
typedef int dns_diff_compare_func(const void *, const void *);

/***
 *** Functions
 ***/

ISC_LANG_BEGINDECLS

/**************************************************************************/
/*
 * Manipulation of diffs and tuples.
 */

isc_result_t
dns_difftuple_create(isc_mem_t *mctx,
                     dns_diffop_t op, dns_name_t *name, dns_ttl_t ttl,
                     dns_rdata_t *rdata, dns_difftuple_t **tp);
/*%<
 * Create a tuple.  Deep copies are made of the name and rdata, so
 * they need not remain valid after the call.
 *
 * Requires:
 *\li   *tp != NULL && *tp == NULL.
 *
 * Returns:
 *\li   ISC_R_SUCCESS
 *  \li    ISC_R_NOMEMORY
 */

void
dns_difftuple_free(dns_difftuple_t **tp);
/*%<
 * Free a tuple.
 *
 * Requires:
 *    \li   **tp is a valid tuple.
 *
 * Ensures:
 *     \li  *tp == NULL
 *      \li All memory used by the tuple is freed.
 */

isc_result_t
dns_difftuple_copy(dns_difftuple_t *orig, dns_difftuple_t **copyp);
/*%<
 * Copy a tuple.
 *
 * Requires:
 * \li  'orig' points to a valid tuple
 *\li   copyp != NULL && *copyp == NULL
 */

void
dns_diff_init(isc_mem_t *mctx, dns_diff_t *diff);
/*%<
 * Initialize a diff.
 *
 * Requires:
 * \li   'diff' points to an uninitialized dns_diff_t
 *  \li  allocated by the caller.
 *
 * Ensures:
 * \li   '*diff' is a valid, empty diff.
 */

void
dns_diff_clear(dns_diff_t *diff);
/*%<
 * Clear a diff, destroying all its tuples.
 *
 * Requires:
 * \li   'diff' points to a valid dns_diff_t.
 *
 * Ensures:
 * \li    Any tuples in the diff are destroyed.
 *     The diff now empty, but it is still valid
 *     and may be reused without calling dns_diff_init
 *     again.  The only memory used is that of the
 *     dns_diff_t structure itself.
 *
 * Notes:
 * \li    Managing the memory of the dns_diff_t structure itself
 *     is the caller's responsibility.
 */

void
dns_diff_append(dns_diff_t *diff, dns_difftuple_t **tuple);
/*%<
 * Append a single tuple to a diff.
 *
 *\li   'diff' is a valid diff.
 * \li  '*tuple' is a valid tuple.
 *
 * Ensures:
 *\li   *tuple is NULL.
 *\li   The tuple has been freed, or will be freed when the diff is cleared.
 */

void
dns_diff_appendminimal(dns_diff_t *diff, dns_difftuple_t **tuple);
/*%<
 * Append 'tuple' to 'diff', removing any duplicate
 * or conflicting updates as needed to create a minimal diff.
 *
 * Requires:
 *\li   'diff' is a minimal diff.
 *
 * Ensures:
 *\li   'diff' is still a minimal diff.
 *  \li         *tuple is NULL.
 *   \li        The tuple has been freed, or will be freed when the diff is cleared.
 *
 */

isc_result_t
dns_diff_sort(dns_diff_t *diff, dns_diff_compare_func *compare);
/*%<
 * Sort 'diff' in-place according to the comparison function 'compare'.
 */

isc_result_t
dns_diff_apply(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver);
isc_result_t
dns_diff_applysilently(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver);
/*%<
 * Apply 'diff' to the database 'db'.
 *
 * dns_diff_apply() logs warnings about updates with no effect or
 * with inconsistent TTLs; dns_diff_applysilently() does not.
 *
 * For efficiency, the diff should be sorted by owner name.
 * If it is not sorted, operation will still be correct,
 * but less efficient.
 *
 * Requires:
 *\li   *diff is a valid diff (possibly empty), containing
 *      tuples of type #DNS_DIFFOP_ADD and/or
 *      For #DNS_DIFFOP_DEL tuples, the TTL is ignored.
 *
 */

isc_result_t
dns_diff_load(dns_diff_t *diff, dns_addrdatasetfunc_t addfunc,
              void *add_private);
/*%<
 * Like dns_diff_apply, but for use when loading a new database
 * instead of modifying an existing one.  This bypasses the
 * database transaction mechanisms.
 *
 * Requires:
 *\li   'addfunc' is a valid dns_addradatasetfunc_t obtained from
 *      dns_db_beginload()
 *
 *\li   'add_private' points to a corresponding dns_dbload_t *
 *      (XXX why is it a void pointer, then?)
 */

isc_result_t
dns_diff_print(dns_diff_t *diff, FILE *file);

/*%<
 * Print the differences to 'file' or if 'file' is NULL via the
 * logging system.
 *
 * Require:
 *\li   'diff' to be valid.
 *\li   'file' to refer to a open file or NULL.
 *
 * Returns:
 *\li   #ISC_R_SUCCESS
 *\li   #ISC_R_NOMEMORY
 *\li   #ISC_R_UNEXPECTED
 *\li   any error from dns_rdataset_totext()
 */

ISC_LANG_ENDDECLS

#endif /* DNS_DIFF_H */

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