lookup.h File Reference

The lookup module performs simple DNS lookups. It implements the full resolver algorithm, both looking for local data and resolving external names as necessary. More...

#include <isc/lang.h>
#include <isc/event.h>
#include <dns/types.h>

Go to the source code of this file.

Data Structures
struct	dns_lookupevent
	A 'dns_lookupevent_t' is returned when a lookup completes. The sender field will be set to the lookup that completed. If 'result' is ISC_R_SUCCESS, then 'names' will contain a list of names associated with the address. The recipient of the event must not change the list and must not refer to any of the name data after the event is freed. More...
Defines
#define	DNS_LOOKUP_H   1
Typedefs
typedef ISC_LANG_BEGINDECLS struct dns_lookupevent	dns_lookupevent_t
Functions
isc_result_t	dns_lookup_create (isc_mem_t *mctx, dns_name_t *name, dns_rdatatype_t type, dns_view_t *view, unsigned int options, isc_task_t *task, isc_taskaction_t action, void *arg, dns_lookup_t **lookupp)
	Finds the rrsets matching 'name' and 'type'.
void	dns_lookup_cancel (dns_lookup_t *lookup)
	Cancel 'lookup'.
void	dns_lookup_destroy (dns_lookup_t **lookupp)
	Destroy 'lookup'.

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Detailed Description

The lookup module performs simple DNS lookups. It implements the full resolver algorithm, both looking for local data and resolving external names as necessary.

MP:

• The module ensures appropriate synchronization of data structures it creates and manipulates.

Reliability:

• No anticipated impact.

Resources:

• TBS

Security:

• No anticipated impact.

Standards:

• RFCs: 1034, 1035, 2181, TBS
• Drafts: TBS

Definition in file lookup.h.

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Define Documentation

#define DNS_LOOKUP_H   1

Definition at line 21 of file lookup.h.

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Typedef Documentation

typedef ISC_LANG_BEGINDECLS struct dns_lookupevent dns_lookupevent_t

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Function Documentation

isc_result_t dns_lookup_create	(	isc_mem_t *	mctx,
		dns_name_t *	name,
		dns_rdatatype_t	type,
		dns_view_t *	view,
		unsigned int	options,
		isc_task_t *	task,
		isc_taskaction_t	action,
		void *	arg,
		dns_lookup_t **	lookupp
	)

Finds the rrsets matching 'name' and 'type'.

Requires:

• 'mctx' is a valid mctx.

• 'name' is a valid name.

• 'view' is a valid view which has a resolver.

• 'task' is a valid task.

• lookupp != NULL && *lookupp == NULL

Returns:

• ISC_R_SUCCESS
• ISC_R_NOMEMORY

• Any resolver-related error (e.g. ISC_R_SHUTTINGDOWN) may also be returned.

Definition at line 385 of file lookup.c.

References dns_lookup::canceled, DESTROYLOCK, DNS_EVENT_LOOKUPDONE, dns_fixedname_init, dns_fixedname_name, dns_name_copy(), dns_rdataset_init(), dns_view_attach(), dns_lookup::event, dns_lookup::fetch, isc_event_allocate(), isc_event_free(), ISC_FALSE, isc_mem_attach(), isc_mem_get, isc_mem_putanddetach, isc_mutex_init, ISC_R_FAILURE, ISC_R_NOMEMORY, ISC_R_SUCCESS, isc_task_attach(), isc_task_detach(), levent_destroy(), dns_lookup::lock, lookup_find(), LOOKUP_MAGIC, dns_lookup::magic, dns_lookup::mctx, dns_lookup::name, dns_lookup::options, dns_lookup::rdataset, dns_lookup::restarts, dns_lookup::sigrdataset, dns_lookup::task, dns_lookup::type, and dns_lookup::view.

Referenced by dns_byaddr_create(), and start_lookup().

void dns_lookup_cancel

(

dns_lookup_t *

lookup

)

Cancel 'lookup'.

Notes:

• If 'lookup' has not completed, post its LOOKUPDONE event with a result code of ISC_R_CANCELED.

Requires:

• 'lookup' is a valid lookup.

Definition at line 462 of file lookup.c.

References dns_lookup::canceled, dns_resolver_cancelfetch(), dns_lookup::fetch, INSIST, ISC_TRUE, dns_lookup::lock, LOCK, REQUIRE, UNLOCK, VALID_LOOKUP, and dns_lookup::view.

Referenced by dns_byaddr_cancel().

void dns_lookup_destroy

(

dns_lookup_t **

lookupp

)

Destroy 'lookup'.

Requires:

• '*lookupp' is a valid lookup.

• The caller has received the LOOKUPDONE event (either because the lookup completed or because dns_lookup_cancel() was called).

Ensures:

• *lookupp == NULL.

Definition at line 479 of file lookup.c.

References DESTROYLOCK, dns_rdataset_disassociate(), dns_rdataset_isassociated(), dns_lookup::event, isc_mem_putanddetach, dns_lookup::lock, dns_lookup::magic, dns_lookup::mctx, dns_lookup::rdataset, REQUIRE, dns_lookup::sigrdataset, dns_lookup::task, VALID_LOOKUP, and dns_lookup::view.

Referenced by dns_byaddr_destroy(), and lookup_done().

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