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/* MIT License
*
* Copyright (c) 1998 Massachusetts Institute of Technology
* Copyright (c) The c-ares project and its contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* SPDX-License-Identifier: MIT
*/
#include "ares_setup.h"
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#include "ares_nameser.h"
#include "ares.h"
#include "ares_dns.h"
#include "ares_private.h"
int ares_send_ex(ares_channel channel, const unsigned char *qbuf, int qlen,
ares_callback callback, void *arg)
{
struct query *query;
int i, packetsz;
struct timeval now;
/* Verify that the query is at least long enough to hold the header. */
if (qlen < HFIXEDSZ || qlen >= (1 << 16))
{
callback(arg, ARES_EBADQUERY, 0, NULL, 0);
return ARES_EBADQUERY;
}
if (channel->nservers < 1)
{
callback(arg, ARES_ESERVFAIL, 0, NULL, 0);
return ARES_ESERVFAIL;
}
/* Allocate space for query and allocated fields. */
query = ares_malloc(sizeof(struct query));
if (!query)
{
callback(arg, ARES_ENOMEM, 0, NULL, 0);
return ARES_ENOMEM;
}
memset(query, 0, sizeof(*query));
query->channel = channel;
query->tcpbuf = ares_malloc(qlen + 2);
if (!query->tcpbuf)
{
ares_free(query);
callback(arg, ARES_ENOMEM, 0, NULL, 0);
return ARES_ENOMEM;
}
query->server_info = ares_malloc(channel->nservers *
sizeof(query->server_info[0]));
if (!query->server_info)
{
ares_free(query->tcpbuf);
ares_free(query);
callback(arg, ARES_ENOMEM, 0, NULL, 0);
return ARES_ENOMEM;
}
/* Compute the query ID. Start with no timeout. */
query->qid = DNS_HEADER_QID(qbuf);
query->timeout.tv_sec = 0;
query->timeout.tv_usec = 0;
/* Form the TCP query buffer by prepending qlen (as two
* network-order bytes) to qbuf.
*/
query->tcpbuf[0] = (unsigned char)((qlen >> 8) & 0xff);
query->tcpbuf[1] = (unsigned char)(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_count = 0;
/* Choose the server to send the query to. If rotation is enabled, keep track
* of the next server we want to use. */
query->server = channel->last_server;
if (channel->rotate == 1)
channel->last_server = (channel->last_server + 1) % channel->nservers;
for (i = 0; i < channel->nservers; i++)
{
query->server_info[i].skip_server = 0;
query->server_info[i].tcp_connection_generation = 0;
}
packetsz = (channel->flags & ARES_FLAG_EDNS) ? channel->ednspsz : PACKETSZ;
query->using_tcp = (channel->flags & ARES_FLAG_USEVC) || qlen > packetsz;
query->error_status = ARES_ECONNREFUSED;
query->timeouts = 0;
/* Initialize our list nodes. */
query->node_queries_by_timeout = NULL;
query->node_queries_to_conn = NULL;
/* Chain the query into the list of all queries. */
query->node_all_queries = ares__llist_insert_last(channel->all_queries, query);
if (query->node_all_queries == NULL) {
callback(arg, ARES_ENOMEM, 0, NULL, 0);
ares__free_query(query);
return ARES_ENOMEM;
}
/* Keep track of queries bucketed by qid, so we can process DNS
* responses quickly.
*/
if (!ares__htable_stvp_insert(channel->queries_by_qid, query->qid, query)) {
callback(arg, ARES_ENOMEM, 0, NULL, 0);
ares__free_query(query);
return ARES_ENOMEM;
}
/* Perform the first query action. */
now = ares__tvnow();
return ares__send_query(channel, query, &now);
}
void ares_send(ares_channel channel, const unsigned char *qbuf, int qlen,
ares_callback callback, void *arg)
{
ares_send_ex(channel, qbuf, qlen, callback, arg);
}
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