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https://gitlab.isc.org/isc-projects/bind9
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f3635bcc14
Unify the header guard style and replace the inconsistent include guards with #pragma once. The #pragma once is widely and very well supported in all compilers that BIND 9 supports, and #pragma once was already in use in several new or refactored headers. Using simpler method will also allow us to automate header guard checks as this is simpler to programatically check. For reference, here are the reasons for the change taken from Wikipedia[1]: > In the C and C++ programming languages, #pragma once is a non-standard > but widely supported preprocessor directive designed to cause the > current source file to be included only once in a single compilation. > > Thus, #pragma once serves the same purpose as include guards, but with > several advantages, including: less code, avoidance of name clashes, > and sometimes improvement in compilation speed. On the other hand, > #pragma once is not necessarily available in all compilers and its > implementation is tricky and might not always be reliable. 1. https://en.wikipedia.org/wiki/Pragma_once
292 lines
8.9 KiB
C
292 lines
8.9 KiB
C
/*
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* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, you can obtain one at https://mozilla.org/MPL/2.0/.
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*
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* See the COPYRIGHT file distributed with this work for additional
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* information regarding copyright ownership.
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*/
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#pragma once
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/*****
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***** Module Info
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*****/
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/*! \file
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*
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* \brief
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* The DNS client module provides convenient programming interfaces to various
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* DNS services, such as name resolution with or without DNSSEC validation or
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* dynamic DNS update. This module is primarily expected to be used by other
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* applications than BIND9-related ones that need such advanced DNS features.
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*
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* MP:
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*\li In the typical usage of this module, application threads will not share
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* the same data structures created and manipulated in this module.
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* However, the module still ensures appropriate synchronization of such
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* data structures.
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*
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* Resources:
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*\li TBS
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*
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* Security:
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*\li This module does not handle any low-level data directly, and so no
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* security issue specific to this module is anticipated.
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*/
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#include <isc/event.h>
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#include <isc/sockaddr.h>
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#include <dns/tsig.h>
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#include <dns/types.h>
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#include <dst/dst.h>
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ISC_LANG_BEGINDECLS
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/***
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*** Types
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***/
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/*%
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* Optional flags for dns_client_(start)resolve.
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*/
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/*%< Do not return DNSSEC data (e.g. RRSIGS) with response. */
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#define DNS_CLIENTRESOPT_NODNSSEC 0x01
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/*%< Allow running external context. */
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#define DNS_CLIENTRESOPT_RESERVED 0x02
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/*%< Don't validate responses. */
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#define DNS_CLIENTRESOPT_NOVALIDATE 0x04
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/*%< Don't set the CD flag on upstream queries. */
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#define DNS_CLIENTRESOPT_NOCDFLAG 0x08
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/*%< Use TCP transport. */
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#define DNS_CLIENTRESOPT_TCP 0x10
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/*%
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* View name used in dns_client.
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*/
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#define DNS_CLIENTVIEW_NAME "_dnsclient"
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/*%
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* A dns_clientresevent_t is sent when name resolution performed by a client
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* completes. 'result' stores the result code of the entire resolution
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* procedure. 'vresult' specifically stores the result code of DNSSEC
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* validation if it is performed. When name resolution successfully completes,
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* 'answerlist' is typically non empty, containing answer names along with
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* RRsets. It is the receiver's responsibility to free this list by calling
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* dns_client_freeresanswer() before freeing the event structure.
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*/
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typedef struct dns_clientresevent {
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ISC_EVENT_COMMON(struct dns_clientresevent);
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isc_result_t result;
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isc_result_t vresult;
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dns_namelist_t answerlist;
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} dns_clientresevent_t; /* too long? */
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isc_result_t
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dns_client_create(isc_mem_t *mctx, isc_appctx_t *actx, isc_taskmgr_t *taskmgr,
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isc_nm_t *nm, isc_timermgr_t *timermgr, unsigned int options,
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dns_client_t **clientp, const isc_sockaddr_t *localaddr4,
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const isc_sockaddr_t *localaddr6);
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/*%<
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* Create a DNS client object with minimal internal resources, such as
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* a default view for the IN class and IPv4/IPv6 dispatches for the view.
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*
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* dns_client_create() takes 'manager' arguments so that the caller can
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* control the behavior of the client through the underlying event framework.
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* 'localaddr4' and 'localaddr6' specify the local addresses to use for
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* each address family; if both are set to NULL, then wildcard addresses
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* will be used for both families. If only one is NULL, then the other
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* address will be used as the local address, and the NULL protocol family
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* will not be used.
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*
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* Requires:
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*
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*\li 'mctx' is a valid memory context.
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*
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*\li 'actx' is a valid application context.
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*
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*\li 'taskmgr' is a valid task manager.
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*
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*\li 'nm' is a valid network manager.
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*
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*\li 'timermgr' is a valid timer manager.
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*
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*\li clientp != NULL && *clientp == NULL.
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*
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* Returns:
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*
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*\li #ISC_R_SUCCESS On success.
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*
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*\li Anything else Failure.
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*/
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void
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dns_client_detach(dns_client_t **clientp);
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/*%<
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* Detach 'client' and destroy it if there are no more references.
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*
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* Requires:
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*
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*\li '*clientp' is a valid client.
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*
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* Ensures:
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*
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*\li *clientp == NULL.
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*/
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isc_result_t
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dns_client_setservers(dns_client_t *client, dns_rdataclass_t rdclass,
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const dns_name_t *name_space, isc_sockaddrlist_t *addrs);
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/*%<
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* Specify a list of addresses of recursive name servers that the client will
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* use for name resolution. A view for the 'rdclass' class must be created
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* beforehand. If 'name_space' is non NULL, the specified server will be used
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* if and only if the query name is a subdomain of 'name_space'. When servers
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* for multiple 'name_space's are provided, and a query name is covered by
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* more than one 'name_space', the servers for the best (longest) matching
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* name_space will be used. If 'name_space' is NULL, it works as if
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* dns_rootname (.) were specified.
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*
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* Requires:
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*
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*\li 'client' is a valid client.
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*
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*\li 'name_space' is NULL or a valid name.
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*
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*\li 'addrs' != NULL.
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*
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* Returns:
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*
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*\li #ISC_R_SUCCESS On success.
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*
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*\li Anything else Failure.
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*/
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isc_result_t
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dns_client_clearservers(dns_client_t *client, dns_rdataclass_t rdclass,
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const dns_name_t *name_space);
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/*%<
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* Remove configured recursive name servers for the 'rdclass' and 'name_space'
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* from the client. See the description of dns_client_setservers() for
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* the requirements about 'rdclass' and 'name_space'.
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*
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* Requires:
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*
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*\li 'client' is a valid client.
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*
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*\li 'name_space' is NULL or a valid name.
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*
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* Returns:
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*
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*\li #ISC_R_SUCCESS On success.
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*
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*\li Anything else Failure.
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*/
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isc_result_t
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dns_client_resolve(dns_client_t *client, const dns_name_t *name,
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dns_rdataclass_t rdclass, dns_rdatatype_t type,
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unsigned int options, dns_namelist_t *namelist);
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isc_result_t
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dns_client_startresolve(dns_client_t *client, const dns_name_t *name,
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dns_rdataclass_t rdclass, dns_rdatatype_t type,
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unsigned int options, isc_task_t *task,
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isc_taskaction_t action, void *arg,
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dns_clientrestrans_t **transp);
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/*%<
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* Perform name resolution for 'name', 'rdclass', and 'type'.
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*
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* If any trusted keys are configured and the query name is considered to
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* belong to a secure zone, these functions also validate the responses
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* using DNSSEC by default. If the DNS_CLIENTRESOPT_NOVALIDATE flag is set
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* in 'options', DNSSEC validation is disabled regardless of the configured
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* trusted keys or the query name. With DNS_CLIENTRESOPT_NODNSSEC
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* DNSSEC data is not returned with response. DNS_CLIENTRESOPT_NOCDFLAG
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* disables the CD flag on queries, DNS_CLIENTRESOPT_TCP switches to
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* the TCP (vs. UDP) transport.
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*
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* dns_client_resolve() provides a synchronous service. This function starts
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* name resolution internally and blocks until it completes. On success,
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* 'namelist' will contain a list of answer names, each of which has
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* corresponding RRsets. The caller must provide a valid empty list, and
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* is responsible for freeing the list content via dns_client_freeresanswer().
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* If the name resolution fails due to an error in DNSSEC validation,
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* dns_client_resolve() returns the result code indicating the validation
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* error. Otherwise, it returns the result code of the entire resolution
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* process, either success or failure.
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*
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* It is expected that the client object passed to dns_client_resolve() was
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* created via dns_client_create() and has external managers and contexts.
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*
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* dns_client_startresolve() is an asynchronous version of dns_client_resolve()
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* and does not block. When name resolution is completed, 'action' will be
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* called with the argument of a 'dns_clientresevent_t' object, which contains
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* the resulting list of answer names (on success). On return, '*transp' is
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* set to an opaque transaction ID so that the caller can cancel this
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* resolution process.
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*
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* Requires:
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*
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*\li 'client' is a valid client.
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*
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*\li 'addrs' != NULL.
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*
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*\li 'name' is a valid name.
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*
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*\li 'namelist' != NULL and is not empty.
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*
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*\li 'task' is a valid task.
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*
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*\li 'transp' != NULL && *transp == NULL;
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*
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* Returns:
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*
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*\li #ISC_R_SUCCESS On success.
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*
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*\li Anything else Failure.
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*/
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void
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dns_client_freeresanswer(dns_client_t *client, dns_namelist_t *namelist);
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/*%<
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* Free resources allocated for the content of 'namelist'.
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*
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* Requires:
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*
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*\li 'client' is a valid client.
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*
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*\li 'namelist' != NULL.
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*/
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isc_result_t
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dns_client_addtrustedkey(dns_client_t *client, dns_rdataclass_t rdclass,
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dns_rdatatype_t rdtype, const dns_name_t *keyname,
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isc_buffer_t *keydatabuf);
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/*%<
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* Add a DNSSEC trusted key for the 'rdclass' class. A view for the 'rdclass'
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* class must be created beforehand. 'rdtype' is the type of the RR data
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* for the key, either DNSKEY or DS. 'keyname' is the DNS name of the key,
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* and 'keydatabuf' stores the RR data.
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*
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* Requires:
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*
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*\li 'client' is a valid client.
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*
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*\li 'keyname' is a valid name.
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*
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*\li 'keydatabuf' is a valid buffer.
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*
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* Returns:
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*
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*\li #ISC_R_SUCCESS On success.
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*
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*\li Anything else Failure.
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*/
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ISC_LANG_ENDDECLS
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