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/* Copyright 1998 by the Massachusetts Institute of Technology.
*
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting
* documentation, and that the name of M.I.T. not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is"
* without express or implied warranty.
*/
static const char rcsid[] = "$Id: ares_query.c,v 1.5 2000/09/21 19:15:58 ghudson Exp $";
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <stdlib.h>
#include "ares.h"
#include "ares_dns.h"
#include "ares_private.h"
struct qquery {
ares_callback callback;
void *arg;
};
static void qcallback(void *arg, int status, unsigned char *abuf, int alen);
void ares_query(ares_channel channel, const char *name, int dnsclass,
int type, ares_callback callback, void *arg)
{
struct qquery *qquery;
unsigned char *qbuf;
int qlen, rd, status;
/* Compose the query. */
rd = !(channel->flags & ARES_FLAG_NORECURSE);
status = ares_mkquery(name, dnsclass, type, channel->next_id, rd, &qbuf,
&qlen);
channel->next_id++;
if (status != ARES_SUCCESS)
{
callback(arg, status, NULL, 0);
return;
}
/* Allocate and fill in the query structure. */
qquery = malloc(sizeof(struct qquery));
if (!qquery)
{
ares_free_string(qbuf);
callback(arg, ARES_ENOMEM, NULL, 0);
return;
}
qquery->callback = callback;
qquery->arg = arg;
/* Send it off. qcallback will be called when we get an answer. */
ares_send(channel, qbuf, qlen, qcallback, qquery);
ares_free_string(qbuf);
}
static void qcallback(void *arg, int status, unsigned char *abuf, int alen)
{
struct qquery *qquery = (struct qquery *) arg;
unsigned int ancount;
int rcode;
if (status != ARES_SUCCESS)
qquery->callback(qquery->arg, status, abuf, alen);
else
{
/* Pull the response code and answer count from the packet. */
rcode = DNS_HEADER_RCODE(abuf);
ancount = DNS_HEADER_ANCOUNT(abuf);
/* Convert errors. */
switch (rcode)
{
case NOERROR:
status = (ancount > 0) ? ARES_SUCCESS : ARES_ENODATA;
break;
case FORMERR:
status = ARES_EFORMERR;
break;
case SERVFAIL:
status = ARES_ESERVFAIL;
break;
case NXDOMAIN:
status = ARES_ENOTFOUND;
break;
case NOTIMP:
status = ARES_ENOTIMP;
break;
case REFUSED:
status = ARES_EREFUSED;
break;
}
qquery->callback(qquery->arg, status, abuf, alen);
}
free(qquery);
}
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