162 lines
5.4 KiB
C
162 lines
5.4 KiB
C
/*
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* iterator/iter_hints.h - iterative resolver module stub and root hints.
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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 stub and root hints, and read those from config.
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*/
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#ifndef ITERATOR_ITER_HINTS_H
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#define ITERATOR_ITER_HINTS_H
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#include "util/storage/dnstree.h"
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struct iter_env;
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struct config_file;
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struct delegpt;
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/**
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* Iterator hints structure
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*/
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struct iter_hints {
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/**
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* Hints 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_hints_stub. The class IN root is in here.
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* uses name_tree_node from dnstree.h.
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*/
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rbtree_type tree;
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};
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/**
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* Iterator hints for a particular stub.
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*/
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struct iter_hints_stub {
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/** tree sorted by name, class */
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struct name_tree_node node;
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/** delegation point with hint information for this stub. malloced. */
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struct delegpt* dp;
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/** does the stub need to forego priming (like on other ports) */
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uint8_t noprime;
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};
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/**
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* Create hints
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* @return new hints or NULL on error.
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*/
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struct iter_hints* hints_create(void);
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/**
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* Delete hints.
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* @param hints: to delete.
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*/
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void hints_delete(struct iter_hints* hints);
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/**
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* Process hints config. Sets default values for root hints if no config.
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* @param hints: 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 hints_apply_cfg(struct iter_hints* hints, struct config_file* cfg);
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/**
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* Find root hints for the given class.
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* @param hints: hint storage.
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* @param qclass: class for which root hints are requested. host order.
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* @return: NULL if no hints, or a ptr to stored hints.
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*/
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struct delegpt* hints_lookup_root(struct iter_hints* hints, uint16_t qclass);
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/**
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* Find next root hints (to cycle through all root hints).
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* @param hints: hint storage
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* @param qclass: class for which root hints are sought.
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* 0 means give the first available root hints class.
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* x means, give class x or a higher class if any.
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* returns the found class in this variable.
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* @return true if a root hint class is found.
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* false if not root hint class is found (qclass may have been changed).
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*/
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int hints_next_root(struct iter_hints* hints, uint16_t* qclass);
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/**
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* Given a qname/qclass combination, and the delegation point from the cache
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* for this qname/qclass, determine if this combination indicates that a
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* stub hint exists and must be primed.
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*
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* @param hints: hint storage.
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* @param qname: The qname that generated the delegation point.
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* @param qclass: The qclass that generated the delegation point.
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* @param dp: The cache generated delegation point.
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* @return: A priming delegation point if there is a stub hint that must
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* be primed, otherwise null.
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*/
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struct iter_hints_stub* hints_lookup_stub(struct iter_hints* hints,
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uint8_t* qname, uint16_t qclass, struct delegpt* dp);
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/**
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* Get memory in use by hints
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* @param hints: hint storage.
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* @return bytes in use
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*/
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size_t hints_get_mem(struct iter_hints* hints);
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/**
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* Add stub to hints structure. For external use since it recalcs
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* the tree parents.
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* @param hints: the hints 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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* hints stub. malloced.
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* @param noprime: set noprime option to true or false on new hint stub.
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* @return false on failure (out of memory);
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*/
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int hints_add_stub(struct iter_hints* hints, uint16_t c, struct delegpt* dp,
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int noprime);
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/**
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* Remove stub from hints structure. For external use since it
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* recalcs the tree parents.
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* @param hints: the hints data structure
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* @param c: class of stub zone
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* @param nm: name of stub zone (in uncompressed wireformat).
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*/
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void hints_delete_stub(struct iter_hints* hints, uint16_t c, uint8_t* nm);
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#endif /* ITERATOR_ITER_HINTS_H */
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