108 строки
2.9 KiB
C
108 строки
2.9 KiB
C
/* $Id$ */
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/* 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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#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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#ifdef HAVE_ARPA_NAMESER_COMPAT_H
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#include <arpa/nameser_compat.h>
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#endif
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <time.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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void ares_send(ares_channel channel, const unsigned char *qbuf, int qlen,
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ares_callback callback, void *arg)
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{
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struct query *query;
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int i;
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time_t now;
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/* Verify that the query is at least long enough to hold the header. */
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if (qlen < HFIXEDSZ || qlen >= (1 << 16))
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{
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callback(arg, ARES_EBADQUERY, NULL, 0);
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return;
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}
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/* Allocate space for query and allocated fields. */
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query = malloc(sizeof(struct query));
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if (!query)
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{
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callback(arg, ARES_ENOMEM, NULL, 0);
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return;
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}
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query->tcpbuf = malloc(qlen + 2);
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if (!query->tcpbuf)
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{
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free(query);
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callback(arg, ARES_ENOMEM, NULL, 0);
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return;
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}
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query->skip_server = malloc(channel->nservers * sizeof(int));
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if (!query->skip_server)
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{
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free(query->tcpbuf);
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free(query);
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callback(arg, ARES_ENOMEM, NULL, 0);
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return;
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}
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/* Compute the query ID. Start with no timeout. */
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query->qid = (unsigned short)DNS_HEADER_QID(qbuf);
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query->timeout = 0;
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/* Form the TCP query buffer by prepending qlen (as two
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* network-order bytes) to qbuf.
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*/
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query->tcpbuf[0] = (unsigned char)((qlen >> 8) & 0xff);
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query->tcpbuf[1] = (unsigned char)(qlen & 0xff);
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memcpy(query->tcpbuf + 2, qbuf, qlen);
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query->tcplen = qlen + 2;
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/* Fill in query arguments. */
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query->qbuf = query->tcpbuf + 2;
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query->qlen = qlen;
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query->callback = callback;
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query->arg = arg;
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/* Initialize query status. */
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query->try = 0;
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query->server = 0;
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for (i = 0; i < channel->nservers; i++)
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query->skip_server[i] = 0;
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query->using_tcp = (channel->flags & ARES_FLAG_USEVC) || qlen > PACKETSZ;
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query->error_status = ARES_ECONNREFUSED;
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/* Chain the query into this channel's query list. */
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query->next = channel->queries;
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channel->queries = query;
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/* Perform the first query action. */
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time(&now);
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ares__send_query(channel, query, now);
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}
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