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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.
*/
#include <sys/types.h>
#ifdef WIN32
#include "nameser.h"
#else
#include <netinet/in.h>
#include <arpa/nameser.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "ares.h"
#include "ares_dns.h"
#include "ares_private.h"
void ares_send(ares_channel channel, const unsigned char *qbuf, int qlen,
ares_callback callback, void *arg)
{
struct query *query;
int i;
time_t now;
/* Verify that the query is at least long enough to hold the header. */
if (qlen < HFIXEDSZ || qlen >= (1 << 16))
{
callback(arg, ARES_EBADQUERY, NULL, 0);
return;
}
/* Allocate space for query and allocated fields. */
query = malloc(sizeof(struct query));
if (!query)
{
callback(arg, ARES_ENOMEM, NULL, 0);
return;
}
query->tcpbuf = malloc(qlen + 2);
if (!query->tcpbuf)
{
free(query);
callback(arg, ARES_ENOMEM, NULL, 0);
return;
}
query->skip_server = malloc(channel->nservers * sizeof(int));
if (!query->skip_server)
{
free(query->tcpbuf);
free(query);
callback(arg, ARES_ENOMEM, NULL, 0);
return;
}
/* Compute the query ID. Start with no timeout. */
query->qid = DNS_HEADER_QID(qbuf);
query->timeout = 0;
/* Form the TCP query buffer by prepending qlen (as two
* network-order bytes) to qbuf.
*/
query->tcpbuf[0] = (qlen >> 8) & 0xff;
query->tcpbuf[1] = qlen & 0xff;
memcpy(query->tcpbuf + 2, qbuf, qlen);
query->tcplen = qlen + 2;
/* Fill in query arguments. */
query->qbuf = query->tcpbuf + 2;
query->qlen = qlen;
query->callback = callback;
query->arg = arg;
/* Initialize query status. */
query->try = 0;
query->server = 0;
for (i = 0; i < channel->nservers; i++)
query->skip_server[i] = 0;
query->using_tcp = (channel->flags & ARES_FLAG_USEVC) || qlen > PACKETSZ;
query->error_status = ARES_ECONNREFUSED;
/* Chain the query into this channel's query list. */
query->next = channel->queries;
channel->queries = query;
/* Perform the first query action. */
time(&now);
ares__send_query(channel, query, now);
}
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