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/*
* iterator/iter_fwd.h - iterative resolver module forward zones.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* This file contains functions to assist the iterator module.
* Keep track of forward zones, and read those from config.
*/
#ifndef ITERATOR_ITER_FWD_H
#define ITERATOR_ITER_FWD_H
#include "util/rbtree.h"
#include "util/locks.h"
struct config_file;
struct delegpt;
/**
* Iterator forward zones structure
*/
struct iter_forwards {
/** lock on the forwards tree.
* When grabbing both this lock and the anchors.lock, this lock
* is grabbed first. When grabbing both this lock and the hints.lock
* this lock is grabbed first. */
lock_rw_type lock;
/**
* Zones are stored in this tree. Sort order is specially chosen.
* first sorted on qclass. Then on dname in nsec-like order, so that
* a lookup on class, name will return an exact match or the closest
* match which gives the ancestor needed.
* contents of type iter_forward_zone.
*/
rbtree_type* tree;
};
/**
* Iterator forward servers for a particular zone.
*/
struct iter_forward_zone {
/** redblacktree node, key is this structure: class and name */
rbnode_type node;
/** name */
uint8_t* name;
/** length of name */
size_t namelen;
/** number of labels in name */
int namelabs;
/** delegation point with forward server information for this zone.
* If NULL then this forward entry is used to indicate that a
* stub-zone with the same name exists, and should be used.
* This delegation point is malloced.
*/
struct delegpt* dp;
/** pointer to parent in tree (or NULL if none) */
struct iter_forward_zone* parent;
/** class. host order. */
uint16_t dclass;
};
/**
* Create forwards
* @return new forwards or NULL on error.
*/
struct iter_forwards* forwards_create(void);
/**
* Delete forwards.
* @param fwd: to delete.
*/
void forwards_delete(struct iter_forwards* fwd);
/**
* Process forwards config.
* @param fwd: where to store.
* @param cfg: config options.
* @return 0 on error.
*/
int forwards_apply_cfg(struct iter_forwards* fwd, struct config_file* cfg);
/**
* Find forward zone exactly by name
* The return value is contents of the forwards structure.
* Caller should lock and unlock a readlock on the forwards structure if nolock
* is set.
* Otherwise caller should unlock the readlock on the forwards structure if a
* value was returned.
* @param fwd: forward storage.
* @param qname: The qname of the query.
* @param qclass: The qclass of the query.
* @param nolock: Skip locking, locking is handled by the caller.
* @return: A delegation point or null.
*/
struct delegpt* forwards_find(struct iter_forwards* fwd, uint8_t* qname,
uint16_t qclass, int nolock);
/**
* Find forward zone information
* For this qname/qclass find forward zone information, returns delegation
* point with server names and addresses, or NULL if no forwarding is needed.
* The return value is contents of the forwards structure.
* Caller should lock and unlock a readlock on the forwards structure if nolock
* is set.
* Otherwise caller should unlock the readlock on the forwards structure if a
* value was returned.
*
* @param fwd: forward storage.
* @param qname: The qname of the query.
* @param qclass: The qclass of the query.
* @param nolock: Skip locking, locking is handled by the caller.
* @return: A delegation point if the query has to be forwarded to that list,
* otherwise null.
*/
struct delegpt* forwards_lookup(struct iter_forwards* fwd,
uint8_t* qname, uint16_t qclass, int nolock);
/**
* Same as forwards_lookup, but for the root only
* @param fwd: forward storage.
* @param qclass: The qclass of the query.
* @param nolock: Skip locking, locking is handled by the caller.
* @return: A delegation point if root forward exists, otherwise null.
*/
struct delegpt* forwards_lookup_root(struct iter_forwards* fwd,
uint16_t qclass, int nolock);
/**
* Find next root item in forwards lookup tree.
* Handles its own locking unless nolock is set. In that case the caller
* should lock and unlock a readlock on the forwards structure.
* @param fwd: the forward storage
* @param qclass: class to look at next, or higher.
* @param nolock: Skip locking, locking is handled by the caller.
* @return false if none found, or if true stored in qclass.
*/
int forwards_next_root(struct iter_forwards* fwd, uint16_t* qclass,
int nolock);
/**
* Get memory in use by forward storage
* Locks and unlocks the structure.
* @param fwd: forward storage.
* @return bytes in use
*/
size_t forwards_get_mem(struct iter_forwards* fwd);
/** compare two fwd entries */
int fwd_cmp(const void* k1, const void* k2);
/**
* Add zone to forward structure. For external use since it recalcs
* the tree parents.
* Handles its own locking unless nolock is set. In that case the caller
* should lock and unlock a writelock on the forwards structure.
* @param fwd: the forward data structure
* @param c: class of zone
* @param dp: delegation point with name and target nameservers for new
* forward zone. malloced.
* @param nolock: Skip locking, locking is handled by the caller.
* @return false on failure (out of memory);
*/
int forwards_add_zone(struct iter_forwards* fwd, uint16_t c,
struct delegpt* dp, int nolock);
/**
* Remove zone from forward structure. For external use since it
* recalcs the tree parents.
* Handles its own locking unless nolock is set. In that case the caller
* should lock and unlock a writelock on the forwards structure.
* @param fwd: the forward data structure
* @param c: class of zone
* @param nm: name of zone (in uncompressed wireformat).
* @param nolock: Skip locking, locking is handled by the caller.
*/
void forwards_delete_zone(struct iter_forwards* fwd, uint16_t c,
uint8_t* nm, int nolock);
/**
* Add stub hole (empty entry in forward table, that makes resolution skip
* a forward-zone because the stub zone should override the forward zone).
* Does not add one if not necessary.
* Handles its own locking unless nolock is set. In that case the caller
* should lock and unlock a writelock on the forwards structure.
* @param fwd: the forward data structure
* @param c: class of zone
* @param nm: name of zone (in uncompressed wireformat).
* @param nolock: Skip locking, locking is handled by the caller.
* @return false on failure (out of memory);
*/
int forwards_add_stub_hole(struct iter_forwards* fwd, uint16_t c,
uint8_t* nm, int nolock);
/**
* Remove stub hole, if one exists.
* Handles its own locking unless nolock is set. In that case the caller
* should lock and unlock a writelock on the forwards structure.
* @param fwd: the forward data structure
* @param c: class of zone
* @param nm: name of zone (in uncompressed wireformat).
* @param nolock: Skip locking, locking is handled by the caller.
*/
void forwards_delete_stub_hole(struct iter_forwards* fwd, uint16_t c,
uint8_t* nm, int nolock);
#endif /* ITERATOR_ITER_FWD_H */
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