112 строки
3.0 KiB
C
112 строки
3.0 KiB
C
/* Copyright 1998 by the Massachusetts Institute of Technology.
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*
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* Permission to use, copy, modify, and distribute this
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* software and its documentation for any purpose and without
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* fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting
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* documentation, and that the name of M.I.T. not be used in
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* advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission.
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* M.I.T. makes no representations about the suitability of
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* this software for any purpose. It is provided "as is"
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* without express or implied warranty.
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*/
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#include "setup.h"
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#include <sys/types.h>
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#if defined(WIN32) && !defined(WATT32)
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#include "nameser.h"
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#else
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#include <netinet/in.h>
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#include <arpa/nameser.h>
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#endif
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#include <stdlib.h>
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#include "ares.h"
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#include "ares_dns.h"
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#include "ares_private.h"
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struct qquery {
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ares_callback callback;
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void *arg;
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};
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static void qcallback(void *arg, int status, unsigned char *abuf, int alen);
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void ares_query(ares_channel channel, const char *name, int dnsclass,
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int type, ares_callback callback, void *arg)
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{
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struct qquery *qquery;
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unsigned char *qbuf;
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int qlen, rd, status;
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/* Compose the query. */
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rd = !(channel->flags & ARES_FLAG_NORECURSE);
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status = ares_mkquery(name, dnsclass, type, channel->next_id, rd, &qbuf,
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&qlen);
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channel->next_id++;
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if (status != ARES_SUCCESS)
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{
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callback(arg, status, NULL, 0);
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return;
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}
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/* Allocate and fill in the query structure. */
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qquery = malloc(sizeof(struct qquery));
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if (!qquery)
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{
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ares_free_string(qbuf);
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callback(arg, ARES_ENOMEM, NULL, 0);
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return;
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}
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qquery->callback = callback;
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qquery->arg = arg;
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/* Send it off. qcallback will be called when we get an answer. */
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ares_send(channel, qbuf, qlen, qcallback, qquery);
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ares_free_string(qbuf);
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}
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static void qcallback(void *arg, int status, unsigned char *abuf, int alen)
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{
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struct qquery *qquery = (struct qquery *) arg;
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unsigned int ancount;
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int rcode;
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if (status != ARES_SUCCESS)
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qquery->callback(qquery->arg, status, abuf, alen);
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else
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{
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/* Pull the response code and answer count from the packet. */
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rcode = DNS_HEADER_RCODE(abuf);
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ancount = DNS_HEADER_ANCOUNT(abuf);
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/* Convert errors. */
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switch (rcode)
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{
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case NOERROR:
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status = (ancount > 0) ? ARES_SUCCESS : ARES_ENODATA;
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break;
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case FORMERR:
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status = ARES_EFORMERR;
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break;
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case SERVFAIL:
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status = ARES_ESERVFAIL;
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break;
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case NXDOMAIN:
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status = ARES_ENOTFOUND;
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break;
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case NOTIMP:
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status = ARES_ENOTIMP;
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break;
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case REFUSED:
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status = ARES_EREFUSED;
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break;
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}
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qquery->callback(qquery->arg, status, abuf, alen);
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}
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free(qquery);
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}
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