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