328 lines
7.2 KiB
C
328 lines
7.2 KiB
C
/*
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* Copyright (C) 1999 Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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#ifndef DNS_RESOLVER_H
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#define DNS_RESOLVER_H 1
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/*****
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***** Module Info
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*****/
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/*
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* DNS Resolver
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*
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* XXX <TBS> XXX
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*
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* MP:
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* The module ensures appropriate synchronization of data structures it
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* creates and manipulates.
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*
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* Reliability:
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* No anticipated impact.
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*
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* Resources:
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* <TBS>
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*
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* Security:
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* No anticipated impact.
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*
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* Standards:
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* RFCs: 1034, 1035, 2181, <TBS>
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* Drafts: <TBS>
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*/
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#include <isc/types.h>
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#include <isc/lang.h>
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#include <isc/event.h>
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#include <isc/socket.h>
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#include <dns/types.h>
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#include <dns/name.h>
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#include <dns/fixedname.h>
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#include <dns/result.h>
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ISC_LANG_BEGINDECLS
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/*
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* A dns_fetchevent_t is sent when a 'fetch' completes. Any of 'db',
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* 'node', 'rdataset', and 'sigrdataset' may be bound. It is the
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* receiver's responsibility to detach before freeing the event.
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*
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* 'rdataset' and 'sigrdataset' are the values that were supplied when
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* dns_resolver_createfetch() was called. They are returned to the
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* caller so that they may be freed.
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*/
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typedef struct dns_fetchevent {
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ISC_EVENT_COMMON(struct dns_fetchevent);
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dns_fetch_t * fetch;
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isc_result_t result;
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dns_rdatatype_t qtype;
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dns_db_t * db;
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dns_dbnode_t * node;
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dns_rdataset_t * rdataset;
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dns_rdataset_t * sigrdataset;
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dns_fixedname_t foundname;
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} dns_fetchevent_t;
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/*
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* Options that modify how a 'fetch' is done.
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*/
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#define DNS_FETCHOPT_TCP 0x01 /* Use TCP. */
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#define DNS_FETCHOPT_UNSHARED 0x02 /* See below. */
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#define DNS_FETCHOPT_RECURSIVE 0x04 /* Set RD? */
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#define DNS_FETCHOPT_NOEDNS0 0x08 /* Do not use EDNS. */
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/*
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* XXXRTH Should this API be made semi-private? (I.e.
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* _dns_resolver_create()).
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*/
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isc_result_t
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dns_resolver_create(dns_view_t *view,
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isc_taskmgr_t *taskmgr, unsigned int ntasks,
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isc_socketmgr_t *socketmgr,
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isc_timermgr_t *timermgr,
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dns_dispatch_t *dispatch, dns_resolver_t **resp);
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/*
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* Create a resolver.
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*
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* Notes:
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*
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* Generally, applications should not create a resolver directly, but
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* should instead call dns_view_createresolver().
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*
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* Requires:
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*
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* 'view' is a valid view.
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*
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* 'taskmgr' is a valid task manager.
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*
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* 'ntasks' > 0.
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*
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* 'socketmgr' is a valid socket manager.
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*
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* 'timermgr' is a valid timer manager.
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*
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* 'dispatch' is a valid dispatcher, or is NULL.
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*
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* *resp != NULL && *resp == NULL.
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*
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* Returns:
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*
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* ISC_R_SUCCESS On success.
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*
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* Anything else Failure.
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*/
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isc_result_t
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dns_resolver_setforwarders(dns_resolver_t *res,
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isc_sockaddrlist_t *forwarders);
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/*
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* Set the default forwarders to be used by the resolver.
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*
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* Requires:
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*
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* 'res' is a valid, unfrozen resolver.
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*
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* 'forwarders' is a valid nonempty list.
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*
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* Returns:
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*
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* ISC_R_SUCCESS
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* ISC_R_NOMEMORY
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*/
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isc_result_t
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dns_resolver_setfwdpolicy(dns_resolver_t *res, dns_fwdpolicy_t fwdpolicy);
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/*
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* Set the default forwarding policy to be used by the resolver.
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*
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* Requires:
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*
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* 'res' is a valid, unfrozen resolver.
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*
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* 'fwdpolicy' is a valid dns_fwdpolicy_t.
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*
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* Returns:
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*
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* ISC_R_SUCCESS
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*/
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void
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dns_resolver_freeze(dns_resolver_t *res);
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/*
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* Freeze resolver.
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*
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* Notes:
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*
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* Certain configuration changes, e.g. setting forwarders,
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* cannot be made after the resolver is frozen. Fetches
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* cannot be created until the resolver is frozen.
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*
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* Requires:
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*
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* 'res' is a valid, unfrozen resolver.
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*
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* Ensures:
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*
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* 'res' is frozen.
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*/
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void
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dns_resolver_whenshutdown(dns_resolver_t *res, isc_task_t *task,
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isc_event_t **eventp);
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/*
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* Send '*eventp' to 'task' when 'res' has completed shutdown.
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*
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* Notes:
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*
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* It is not safe to detach the last reference to 'res' until
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* shutdown is complete.
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*
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* Requires:
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*
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* 'res' is a valid resolver.
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*
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* 'task' is a valid task.
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*
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* *eventp is a valid event.
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*
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* Ensures:
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*
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* *eventp == NULL.
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*/
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void
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dns_resolver_shutdown(dns_resolver_t *res);
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/*
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* Start the shutdown process for 'res'.
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*
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* Notes:
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*
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* This call has no effect if the resolver is already shutting down.
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*
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* Requires:
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*
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* 'res' is a valid resolver.
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*/
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void
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dns_resolver_attach(dns_resolver_t *source, dns_resolver_t **targetp);
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void
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dns_resolver_detach(dns_resolver_t **resp);
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isc_result_t
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dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name,
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dns_rdatatype_t type,
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dns_name_t *domain, dns_rdataset_t *nameservers,
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dns_forwarders_t *forwarders,
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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_rdataset_t *rdataset,
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dns_rdataset_t *sigrdataset,
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dns_fetch_t **fetchp);
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/*
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* Recurse to answer a question.
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*
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* Notes:
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*
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* This call starts a query for 'name', type 'type'.
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*
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* XXXRTH Explain query domain and nameservers.
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* Also, we should make them optional and have the resolver
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* do dns_view_findzonecut().
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* 'forwarders' is unimplmented, and subject to change when
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* we figure out how selective forwarding will work.
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*
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* When the fetch completes (successfully or otherwise), a
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* DNS_EVENT_FETCHDONE event with action 'action' and arg 'arg' will be
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* posted to 'task'.
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*
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* The values of 'rdataset' and 'sigrdataset' will be returned in
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* the FETCHDONE event.
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*
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* Requires:
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*
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* 'res' is a valid resolver that has been frozen.
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*
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* 'name' is a valid name.
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*
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* 'type' is not a meta type other than ANY.
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*
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* 'domain' is a valid name.
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*
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* 'nameservers' is a valid NS rdataset (whose owner name is 'domain').
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*
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* 'forwarders' is NULL.
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*
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* 'options' contains valid options.
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*
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* 'rdataset' is a valid, disassociated rdataset.
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*
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* 'sigrdataset' is NULL, or is a valid, disassociated rdataset.
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*
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* fetchp != NULL && *fetchp == NULL.
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*
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* Returns:
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*
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* ISC_R_SUCCESS Success
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*
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* Many other values are possible, all of which indicate failure.
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*/
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void
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dns_resolver_cancelfetch(dns_resolver_t *res, dns_fetch_t *fetch);
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/*
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* Cancel 'fetch'.
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*
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* Notes:
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*
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* If 'fetch' has not completed, post its FETCHDONE event with a
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* result code of ISC_R_CANCELED.
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*
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* Requires:
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*
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* 'res' is a valid resolver that has been frozen.
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*
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* 'fetch' is a valid fetch.
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*/
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void
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dns_resolver_destroyfetch(dns_resolver_t *res, dns_fetch_t **fetchp);
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/*
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* Destroy 'fetch'.
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*
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* Requires:
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*
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* 'res' is a valid resolver that has been frozen.
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*
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* '*fetchp' is a valid fetch.
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*
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* The caller has received the FETCHDONE event (either because the
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* fetch completed or because dns_resolver_cancelfetch() was called).
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*
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* Ensures:
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*
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* *fetchp == NULL.
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*/
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ISC_LANG_ENDDECLS
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#endif /* DNS_RESOLVER_H */
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