411 lines
17 KiB
C
411 lines
17 KiB
C
/*
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* validator/val_utils.h - validator utility functions.
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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 helper functions for the validator module.
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*/
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#ifndef VALIDATOR_VAL_UTILS_H
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#define VALIDATOR_VAL_UTILS_H
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#include "util/data/packed_rrset.h"
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struct query_info;
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struct reply_info;
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struct val_env;
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struct module_env;
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struct ub_packed_rrset_key;
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struct key_entry_key;
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struct regional;
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struct val_anchors;
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struct rrset_cache;
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struct sock_list;
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/**
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* Response classifications for the validator. The different types of proofs.
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*/
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enum val_classification {
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/** Not subtyped yet. */
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VAL_CLASS_UNTYPED = 0,
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/** Not a recognized subtype. */
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VAL_CLASS_UNKNOWN,
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/** A positive, direct, response */
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VAL_CLASS_POSITIVE,
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/** A positive response, with a CNAME/DNAME chain. */
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VAL_CLASS_CNAME,
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/** A NOERROR/NODATA response. */
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VAL_CLASS_NODATA,
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/** A NXDOMAIN response. */
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VAL_CLASS_NAMEERROR,
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/** A CNAME/DNAME chain, and the offset is at the end of it,
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* but there is no answer here, it can be NAMERROR or NODATA. */
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VAL_CLASS_CNAMENOANSWER,
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/** A referral, from cache with a nonRD query. */
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VAL_CLASS_REFERRAL,
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/** A response to a qtype=ANY query. */
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VAL_CLASS_ANY
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};
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/**
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* Given a response, classify ANSWER responses into a subtype.
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* @param query_flags: query flags for the original query.
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* @param origqinf: query info. The original query name.
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* @param qinf: query info. The chased query name.
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* @param rep: response. The original response.
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* @param skip: offset into the original response answer section.
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* @return A subtype, all values possible except UNTYPED .
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* Once CNAME type is returned you can increase skip.
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* Then, another CNAME type, CNAME_NOANSWER or POSITIVE are possible.
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*/
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enum val_classification val_classify_response(uint16_t query_flags,
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struct query_info* origqinf, struct query_info* qinf,
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struct reply_info* rep, size_t skip);
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/**
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* Given a response, determine the name of the "signer". This is primarily
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* to determine if the response is, in fact, signed at all, and, if so, what
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* is the name of the most pertinent keyset.
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*
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* @param subtype: the type from classify.
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* @param qinf: query, the chased query name.
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* @param rep: response to that, original response.
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* @param cname_skip: how many answer rrsets have been skipped due to CNAME
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* chains being chased around.
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* @param signer_name: signer name, if the response is signed
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* (even partially), or null if the response isn't signed.
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* @param signer_len: length of signer_name of 0 if signer_name is NULL.
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*/
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void val_find_signer(enum val_classification subtype,
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struct query_info* qinf, struct reply_info* rep,
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size_t cname_skip, uint8_t** signer_name, size_t* signer_len);
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/**
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* Verify RRset with keys
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* @param env: module environment (scratch buffer)
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* @param ve: validator environment (verification settings)
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* @param rrset: what to verify
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* @param keys: dnskey rrset to verify with.
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* @param sigalg: if nonNULL provide downgrade protection otherwise one
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* algorithm is enough. Algo list is constructed in here.
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* @param reason: reason of failure. Fixed string or alloced in scratch.
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* @return security status of verification.
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*/
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enum sec_status val_verify_rrset(struct module_env* env, struct val_env* ve,
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struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* keys,
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uint8_t* sigalg, char** reason);
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/**
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* Verify RRset with keys from a keyset.
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* @param env: module environment (scratch buffer)
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* @param ve: validator environment (verification settings)
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* @param rrset: what to verify
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* @param kkey: key_entry to verify with.
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* @param reason: reason of failure. Fixed string or alloced in scratch.
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* @return security status of verification.
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*/
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enum sec_status val_verify_rrset_entry(struct module_env* env,
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struct val_env* ve, struct ub_packed_rrset_key* rrset,
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struct key_entry_key* kkey, char** reason);
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/**
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* Verify DNSKEYs with DS rrset. Like val_verify_new_DNSKEYs but
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* returns a sec_status instead of a key_entry.
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* @param env: module environment (scratch buffer)
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* @param ve: validator environment (verification settings)
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* @param dnskey_rrset: DNSKEY rrset to verify
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* @param ds_rrset: DS rrset to verify with.
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* @param sigalg: if nonNULL provide downgrade protection otherwise one
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* algorithm is enough. The list of signalled algorithms is returned,
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* must have enough space for ALGO_NEEDS_MAX+1.
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* @param reason: reason of failure. Fixed string or alloced in scratch.
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* @return: sec_status_secure if a DS matches.
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* sec_status_insecure if end of trust (i.e., unknown algorithms).
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* sec_status_bogus if it fails.
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*/
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enum sec_status val_verify_DNSKEY_with_DS(struct module_env* env,
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struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset,
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struct ub_packed_rrset_key* ds_rrset, uint8_t* sigalg, char** reason);
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/**
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* Verify DNSKEYs with DS and DNSKEY rrset. Like val_verify_DNSKEY_with_DS
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* but for a trust anchor.
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* @param env: module environment (scratch buffer)
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* @param ve: validator environment (verification settings)
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* @param dnskey_rrset: DNSKEY rrset to verify
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* @param ta_ds: DS rrset to verify with.
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* @param ta_dnskey: DNSKEY rrset to verify with.
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* @param sigalg: if nonNULL provide downgrade protection otherwise one
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* algorithm is enough. The list of signalled algorithms is returned,
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* must have enough space for ALGO_NEEDS_MAX+1.
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* @param reason: reason of failure. Fixed string or alloced in scratch.
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* @return: sec_status_secure if a DS matches.
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* sec_status_insecure if end of trust (i.e., unknown algorithms).
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* sec_status_bogus if it fails.
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*/
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enum sec_status val_verify_DNSKEY_with_TA(struct module_env* env,
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struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset,
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struct ub_packed_rrset_key* ta_ds,
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struct ub_packed_rrset_key* ta_dnskey, uint8_t* sigalg, char** reason);
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/**
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* Verify new DNSKEYs with DS rrset. The DS contains hash values that should
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* match the DNSKEY keys.
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* match the DS to a DNSKEY and verify the DNSKEY rrset with that key.
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*
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* @param region: where to allocate key entry result.
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* @param env: module environment (scratch buffer)
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* @param ve: validator environment (verification settings)
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* @param dnskey_rrset: DNSKEY rrset to verify
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* @param ds_rrset: DS rrset to verify with.
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* @param downprot: if true provide downgrade protection otherwise one
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* algorithm is enough.
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* @param reason: reason of failure. Fixed string or alloced in scratch.
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* @return a KeyEntry. This will either contain the now trusted
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* dnskey_rrset, a "null" key entry indicating that this DS
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* rrset/DNSKEY pair indicate an secure end to the island of trust
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* (i.e., unknown algorithms), or a "bad" KeyEntry if the dnskey
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* rrset fails to verify. Note that the "null" response should
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* generally only occur in a private algorithm scenario: normally
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* this sort of thing is checked before fetching the matching DNSKEY
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* rrset.
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* if downprot is set, a key entry with an algo list is made.
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*/
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struct key_entry_key* val_verify_new_DNSKEYs(struct regional* region,
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struct module_env* env, struct val_env* ve,
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struct ub_packed_rrset_key* dnskey_rrset,
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struct ub_packed_rrset_key* ds_rrset, int downprot, char** reason);
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/**
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* Verify rrset with trust anchor: DS and DNSKEY rrset.
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*
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* @param region: where to allocate key entry result.
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* @param env: module environment (scratch buffer)
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* @param ve: validator environment (verification settings)
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* @param dnskey_rrset: DNSKEY rrset to verify
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* @param ta_ds_rrset: DS rrset to verify with.
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* @param ta_dnskey_rrset: the DNSKEY rrset to verify with.
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* @param downprot: if true provide downgrade protection otherwise one
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* algorithm is enough.
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* @param reason: reason of failure. Fixed string or alloced in scratch.
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* @return a KeyEntry. This will either contain the now trusted
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* dnskey_rrset, a "null" key entry indicating that this DS
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* rrset/DNSKEY pair indicate an secure end to the island of trust
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* (i.e., unknown algorithms), or a "bad" KeyEntry if the dnskey
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* rrset fails to verify. Note that the "null" response should
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* generally only occur in a private algorithm scenario: normally
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* this sort of thing is checked before fetching the matching DNSKEY
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* rrset.
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* if downprot is set, a key entry with an algo list is made.
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*/
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struct key_entry_key* val_verify_new_DNSKEYs_with_ta(struct regional* region,
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struct module_env* env, struct val_env* ve,
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struct ub_packed_rrset_key* dnskey_rrset,
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struct ub_packed_rrset_key* ta_ds_rrset,
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struct ub_packed_rrset_key* ta_dnskey_rrset,
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int downprot, char** reason);
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/**
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* Determine if DS rrset is usable for validator or not.
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* Returns true if the algorithms for key and DShash are supported,
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* for at least one RR.
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*
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* @param ds_rrset: the newly received DS rrset.
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* @return true or false if not usable.
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*/
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int val_dsset_isusable(struct ub_packed_rrset_key* ds_rrset);
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/**
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* Determine by looking at a signed RRset whether or not the RRset name was
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* the result of a wildcard expansion. If so, return the name of the
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* generating wildcard.
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*
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* @param rrset The rrset to chedck.
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* @param wc: the wildcard name, if the rrset was synthesized from a wildcard.
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* unchanged if not. The wildcard name, without "*." in front, is
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* returned. This is a pointer into the rrset owner name.
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* @return false if the signatures are inconsistent in indicating the
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* wildcard status; possible spoofing of wildcard response for other
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* responses is being tried. We lost the status which rrsig was verified
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* after the verification routine finished, so we simply check if
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* the signatures are consistent; inserting a fake signature is a denial
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* of service; but in that you could also have removed the real
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* signature anyway.
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*/
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int val_rrset_wildcard(struct ub_packed_rrset_key* rrset, uint8_t** wc);
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/**
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* Chase the cname to the next query name.
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* @param qchase: the current query name, updated to next target.
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* @param rep: original message reply to look at CNAMEs.
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* @param cname_skip: the skip into the answer section. Updated to skip
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* DNAME and CNAME to the next part of the answer.
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* @return false on error (bad rdata).
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*/
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int val_chase_cname(struct query_info* qchase, struct reply_info* rep,
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size_t* cname_skip);
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/**
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* Fill up the chased reply with the content from the original reply;
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* as pointers to those rrsets. Select the part after the cname_skip into
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* the answer section, NS and AR sections that are signed with same signer.
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*
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* @param chase: chased reply, filled up.
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* @param orig: original reply.
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* @param cname_skip: which part of the answer section to skip.
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* The skipped part contains CNAME(and DNAME)s that have been chased.
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* @param name: the signer name to look for.
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* @param len: length of name.
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* @param signer: signer name or NULL if an unsigned RRset is considered.
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* If NULL, rrsets with the lookup name are copied over.
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*/
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void val_fill_reply(struct reply_info* chase, struct reply_info* orig,
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size_t cname_skip, uint8_t* name, size_t len, uint8_t* signer);
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/**
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* Remove rrset with index from reply, from the authority section.
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* @param rep: reply to remove it from.
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* @param index: rrset to remove, must be in the authority section.
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*/
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void val_reply_remove_auth(struct reply_info* rep, size_t index);
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/**
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* Remove all unsigned or non-secure status rrsets from NS and AR sections.
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* So that unsigned data does not get let through to clients, when we have
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* found the data to be secure.
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*
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* @param ve: validator environment with cleaning options.
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* @param rep: reply to dump all nonsecure stuff out of.
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*/
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void val_check_nonsecure(struct val_env* ve, struct reply_info* rep);
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/**
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* Mark all unchecked rrset entries not below a trust anchor as indeterminate.
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* Only security==unchecked rrsets are updated.
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* @param rep: the reply with rrsets.
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* @param anchors: the trust anchors.
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* @param r: rrset cache to store updated security status into.
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* @param env: module environment
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*/
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void val_mark_indeterminate(struct reply_info* rep,
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struct val_anchors* anchors, struct rrset_cache* r,
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struct module_env* env);
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/**
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* Mark all unchecked rrset entries below a NULL key entry as insecure.
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* Only security==unchecked rrsets are updated.
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* @param rep: the reply with rrsets.
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* @param kname: end of secure space name.
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* @param r: rrset cache to store updated security status into.
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* @param env: module environment
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*/
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void val_mark_insecure(struct reply_info* rep, uint8_t* kname,
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struct rrset_cache* r, struct module_env* env);
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/**
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* Find next unchecked rrset position, return it for skip.
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* @param rep: the original reply to look into.
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* @param skip: the skip now.
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* @return new skip, which may be at the rep->rrset_count position to signal
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* there are no unchecked items.
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*/
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size_t val_next_unchecked(struct reply_info* rep, size_t skip);
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/**
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* Find the signer name for an RRset.
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* @param rrset: the rrset.
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* @param sname: signer name is returned or NULL if not signed.
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* @param slen: length of sname (or 0).
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*/
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void val_find_rrset_signer(struct ub_packed_rrset_key* rrset, uint8_t** sname,
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size_t* slen);
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/**
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* Get string to denote the classification result.
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* @param subtype: from classification function.
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* @return static string to describe the classification.
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*/
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const char* val_classification_to_string(enum val_classification subtype);
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/**
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* Add existing list to blacklist.
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* @param blacklist: the blacklist with result
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* @param region: the region where blacklist is allocated.
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* Allocation failures are logged.
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* @param origin: origin list to add, if NULL, a cache-entry is added to
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* the blacklist to stop cache from being used.
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* @param cross: if true this is a cross-qstate copy, and the 'origin'
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* list is not allocated in the same region as the blacklist.
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*/
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void val_blacklist(struct sock_list** blacklist, struct regional* region,
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struct sock_list* origin, int cross);
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/**
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* check if has dnssec info, and if it has signed nsecs. gives error reason.
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* @param rep: reply to check.
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* @param reason: returned on fail.
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* @return false if message has no signed nsecs. Can not prove negatives.
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*/
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int val_has_signed_nsecs(struct reply_info* rep, char** reason);
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/**
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* Return algo number for favorite (best) algorithm that we support in DS.
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* @param ds_rrset: the DSes in this rrset are inspected and best algo chosen.
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* @return algo number or 0 if none supported. 0 is unused as algo number.
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*/
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int val_favorite_ds_algo(struct ub_packed_rrset_key* ds_rrset);
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/**
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* Find DS denial message in cache. Saves new qstate allocation and allows
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* the validator to use partial content which is not enough to construct a
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* message for network (or user) consumption. Without SOA for example,
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* which is a common occurrence in the unbound code since the referrals contain
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* NSEC/NSEC3 rrs without the SOA element, thus do not allow synthesis of a
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* full negative reply, but do allow synthesis of sufficient proof.
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* @param env: query env with caches and time.
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* @param nm: name of DS record sought.
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* @param nmlen: length of name.
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* @param c: class of DS RR.
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* @param region: where to allocate result.
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* @param topname: name of the key that is currently in use, that will get
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* used to validate the result, and thus no higher entries from the
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* negative cache need to be examined.
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* @return a dns_msg on success. NULL on failure.
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*/
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struct dns_msg* val_find_DS(struct module_env* env, uint8_t* nm, size_t nmlen,
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uint16_t c, struct regional* region, uint8_t* topname);
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#endif /* VALIDATOR_VAL_UTILS_H */
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