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/*!
* \file zonedb.h
*
* \author Lubos Slovak <lubos.slovak@nic.cz>
*
* \brief Zone database structure and API for manipulating it.
*
* Zone database groups several zones and provides functions for finding
* suitable zone for a domain name, for searching in a particular zone, etc.
*
* \addtogroup libknot
* @{
*/
/* Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
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 3 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, see <http://www.gnu.org/licenses/>.
*/
#ifndef _KNOT_ZONEDB_H_
#define _KNOT_ZONEDB_H_
#include "libknot/zone/zone.h"
#include "libknot/zone/node.h"
#include "libknot/dname.h"
/*
* Zone DB represents a list of managed zones.
* Hashing should be avoided as it is expensive when only a small number of
* zones is present (TLD case). Linear run-length algorithms or worse should
* be avoided as well, as the number of zones may be large.
*
* Use of string-based algorithms for suffix search is viable, but would require
* transformation each time a name is searched. That again would be a
* constant cost even if the number of zones would be small.
*
* Zone database structure is a stack of zones grouped by label count in
* descending order (root label not counted), therefore first match is the longest.
* Each stack level is sorted for convenient binary search.
* example:
* {3 labels, 2 items} => [ 'a.b.c', 'b.b.c' ]
* {2 labels, 1 items} => [ 'x.z' ]
* {1 labels, 2 items} => [ 'y', 'w' ]
*
* Stack is built on top of the sorted array of zones for direct access and
* less memory requirements.
*/
typedef struct {
unsigned labels;
unsigned count;
knot_zone_t** array;
} knot_zonedb_stack_t;
typedef struct {
unsigned count, reserved;
knot_zone_t **array;
unsigned stack_height;
knot_zonedb_stack_t stack[KNOT_DNAME_MAXLABELS];
} knot_zonedb_t;
/*----------------------------------------------------------------------------*/
/*!
* \brief Allocates and initializes the zone database structure.
*
* \return Pointer to the created zone database structure or NULL if an error
* occured.
*/
knot_zonedb_t *knot_zonedb_new(unsigned size);
/*!
* \brief Adds new zone to the database.
*
* \param db Zone database to store the zone.
* \param zone Parsed zone.
*
* \retval KNOT_EOK
* \retval KNOT_EZONEIN
*/
int knot_zonedb_add_zone(knot_zonedb_t *db, knot_zone_t *zone);
/*!
* \brief Removes the given zone from the database if it exists.
*
* \param db Zone database to remove from.
* \param zone_name Name of the zone to be removed.
*
* \retval KNOT_EOK
* \retval KNOT_ENOZONE
*/
knot_zone_t * knot_zonedb_remove_zone(knot_zonedb_t *db,
const knot_dname_t *zone_name);
/*!
* \brief Build zone stack for faster lookup.
*
* Zone stack structure is described in the knot_zonedb_t struct.
*
* \param db Zone database.
* \retval KNOT_EOK
* \retval KNOT_ENOMEM
* \retval KNOT_EINVAL
*/
int knot_zonedb_build_index(knot_zonedb_t *db);
/*!
* \brief Finds zone exactly matching the given zone name.
*
* \param db Zone database to search in.
* \param zone_name Domain name representing the zone name.
*
* \return Zone with \a zone_name being the owner of the zone apex or NULL if
* not found.
*/
knot_zone_t *knot_zonedb_find_zone(knot_zonedb_t *db,
const knot_dname_t *zone_name);
/*!
* \brief Finds zone the given domain name should belong to.
*
* \param db Zone database to search in.
* \param dname Domain name to find zone for.
*
* \retval Zone in which the domain name should be present or NULL if no such
* zone is found.
*/
knot_zone_t *knot_zonedb_find_zone_for_name(knot_zonedb_t *db,
const knot_dname_t *dname);
knot_zone_contents_t *knot_zonedb_expire_zone(knot_zonedb_t *db,
const knot_dname_t *zone_name);
size_t knot_zonedb_zone_count(const knot_zonedb_t *db);
const knot_zone_t **knot_zonedb_zones(const knot_zonedb_t *db);
/*!
* \brief Destroys and deallocates the zone database structure (but not the
* zones within).
*
* \param db Zone database to be destroyed.
*/
void knot_zonedb_free(knot_zonedb_t **db);
/*!
* \brief Destroys and deallocates the whole zone database including the zones.
*
* \param db Zone database to be destroyed.
*/
void knot_zonedb_deep_free(knot_zonedb_t **db);
/*----------------------------------------------------------------------------*/
#endif /* _KNOT_ZONEDB_H_ */
/*! @} */
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