sofia-resolv/sres_async.h File Reference

Asynchronous interface for Sofia DNS Resolver. More...

#include "sofia-resolv/sres_config.h"

Include dependency graph for sres_async.h:

Go to the source code of this file.

Defines
#define	SOFIA_RESOLV_SRES_ASYNC_H
	Defined when <sofia-resolv/sres_async.h> has been included.
Typedefs
typedef SRES_ASYNC_T	sres_async_t
	Application-defined type for context used by asynchronous operation.
typedef int	sres_update_f (sres_async_t *async, sres_socket_t new_socket, sres_socket_t old_socket)
	Prototype for update function.
typedef int	sres_schedule_f (sres_async_t *async, unsigned long interval)
	Prototype for scheduler function.
Functions
SRESPUBFUN sres_async_t *	sres_resolver_set_async (sres_resolver_t *res, sres_update_f *update, sres_async_t *async, int update_all)
	Set asynchronous operation data.
SRESPUBFUN sres_async_t *	sres_resolver_get_async (sres_resolver_t const *res, sres_update_f *update)
	Get async operation data.
SRESPUBFUN int	sres_resolver_sockets (sres_resolver_t *, sres_socket_t *sockets, int n)
	Create sockets for resolver.
SRESPUBFUN void	sres_resolver_timer (sres_resolver_t *, int dummy)
	Resolver timer function.
SRESPUBFUN int	sres_resolver_set_timer_cb (sres_resolver_t *res, sres_schedule_f *callback, sres_async_t *async)
	Register resolver timer callback.
SRESPUBFUN int	sres_resolver_receive (sres_resolver_t *, int socket)
	Receive DNS response from socket.
SRESPUBFUN int	sres_resolver_error (sres_resolver_t *, int socket)
	Receive error message from socket.

---

Detailed Description

Asynchronous interface for Sofia DNS Resolver.

Author:

Pekka Pessi <Pekka.Pessi@nokia-email.address.hidden>

Include Context

 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <sofia-resolv/sres.h>
 #include <sofia-resolv/sres_async.h>

---

Define Documentation

#define SOFIA_RESOLV_SRES_ASYNC_H

Defined when <sofia-resolv/sres_async.h> has been included.

---

Typedef Documentation

typedef SRES_ASYNC_T sres_async_t

Application-defined type for context used by asynchronous operation.

typedef int sres_schedule_f(sres_async_t *async, unsigned long interval)

Prototype for scheduler function.

This function is called when a timer callback is to be scheduled.

Parameters:

	async	asynchronous object (registered with sres_resolver_set_async())
	interval	interval in milliseconds

Return values:

	0	when successful
	-1	upon an error

typedef int sres_update_f(sres_async_t *async, sres_socket_t new_socket, sres_socket_t old_socket)

Prototype for update function.

This kind of function is called when the nameserver configuration has been updated.

If the old_socket is not -1, it indicates that old_socket will be closed and it should be removed from poll() or select() set.

If the new_socket is not -1, it indicates that resolver has created new socket that should be added to the poll() or select() set.

See also:

sres_resolver_set_async(), sres_resolver_get_async()

---

Function Documentation

SRESPUBFUN int sres_resolver_error	(	sres_resolver_t *	res,
		int	socket
	)

Receive error message from socket.

SRESPUBFUN sres_async_t* sres_resolver_get_async	(	sres_resolver_t const *	res,
		sres_update_f *	callback
	)

Get async operation data.

SRESPUBFUN int sres_resolver_receive	(	sres_resolver_t *	res,
		int	socket
	)

Receive DNS response from socket.

SRESPUBFUN sres_async_t* sres_resolver_set_async	(	sres_resolver_t *	res,
		sres_update_f *	callback,
		sres_async_t *	async,
		int	update_all
	)

Set asynchronous operation data.

Set asynchronous operation data.

Returns:

Set async object.

Errors:

EFAULT res points outside the address space

EALREADY different async callback already set

SRESPUBFUN int sres_resolver_set_timer_cb	(	sres_resolver_t *	res,
		sres_schedule_f *	callback,
		sres_async_t *	async
	)

Register resolver timer callback.

SRESPUBFUN int sres_resolver_sockets	(	sres_resolver_t *	res,
		sres_socket_t *	return_sockets,
		int	n
	)

Create sockets for resolver.

SRESPUBFUN void sres_resolver_timer	(	sres_resolver_t *	res,
		int	dummy
	)

Resolver timer function.

The function sresolver_timer() should be called in regular intervals. We recommend calling it in 500 ms intervals.

Parameters:

	res	pointer to resolver object
	dummy	argument for compatibility

Every time it is called it goes through all query structures, and retransmits all the query messages, which have not been answered yet.