7b3913da60
1. Adopt an exponential backoff strategy () to dynamically adjust the timeout duration, which is suitable for retry scenarios. 2. Optimize the default configuration to set the initial timeout to 5 seconds. 3. Support dynamic modification of the maximum timeout limit to adapt to different scenarios. Reference: RFC 1536 (section on retransmission implementation recommendations) Signed-off-by: nuttxs <zhaoqing.zhang@sony.com>
128 lines
3.9 KiB
C
128 lines
3.9 KiB
C
/****************************************************************************
|
|
* libs/libc/netdb/lib_dnsbind.c
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <sys/time.h>
|
|
#include <unistd.h>
|
|
#include <errno.h>
|
|
#include <debug.h>
|
|
|
|
#include <nuttx/net/dns.h>
|
|
|
|
#include "netdb/lib_dns.h"
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
#ifndef CONFIG_NET_SOCKOPTS
|
|
# error CONFIG_NET_SOCKOPTS required by this logic
|
|
#endif
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: dns_bind
|
|
*
|
|
* Description:
|
|
* Initialize the DNS resolver and return a socket bound to the DNS name
|
|
* server. The name server was previously selected via dns_server().
|
|
*
|
|
* Input Parameters:
|
|
* retry_count - Current retry attempt (0 for first attempt)
|
|
* stream - Whether to use stream socket
|
|
*
|
|
* Returned Value:
|
|
* On success, the bound, non-negative socket descriptor is returned. A
|
|
* negated errno value is returned on any failure.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int dns_bind(sa_family_t family, bool stream, int retry_count)
|
|
{
|
|
int stype = stream ? SOCK_STREAM : SOCK_DGRAM;
|
|
struct timeval tv;
|
|
int sd;
|
|
int ret;
|
|
int timeout_sec;
|
|
|
|
/* Calculate progressive timeout: (base timeout * 2^retry_count)
|
|
* For retry_count 0: base timeout, 1: base*2, 2: base*4, etc.
|
|
*/
|
|
|
|
timeout_sec = CONFIG_NETDB_DNSCLIENT_RECV_TIMEOUT;
|
|
if (retry_count > 0)
|
|
{
|
|
/* Apply exponential backoff with configurable maximum */
|
|
|
|
timeout_sec = timeout_sec << retry_count;
|
|
if (CONFIG_NETDB_DNSCLIENT_MAX_TIMEOUT > 0 &&
|
|
timeout_sec > CONFIG_NETDB_DNSCLIENT_MAX_TIMEOUT)
|
|
{
|
|
timeout_sec = CONFIG_NETDB_DNSCLIENT_MAX_TIMEOUT;
|
|
}
|
|
}
|
|
|
|
/* Create a new socket */
|
|
|
|
sd = socket(family, stype | SOCK_CLOEXEC, 0);
|
|
if (sd < 0)
|
|
{
|
|
ret = -get_errno();
|
|
nerr("ERROR: socket() failed: %d\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
/* Set up a receive timeout with progressive strategy */
|
|
|
|
tv.tv_sec = timeout_sec;
|
|
tv.tv_usec = 0;
|
|
|
|
ret = setsockopt(sd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(struct timeval));
|
|
if (ret >= 0)
|
|
{
|
|
/* Set up a send timeout (same progressive strategy) */
|
|
|
|
tv.tv_sec = timeout_sec;
|
|
tv.tv_usec = 0;
|
|
|
|
ret = setsockopt(sd, SOL_SOCKET, SO_SNDTIMEO, &tv,
|
|
sizeof(struct timeval));
|
|
}
|
|
|
|
if (ret < 0)
|
|
{
|
|
ret = -get_errno();
|
|
nerr("ERROR: setsockopt() failed: %d\n", ret);
|
|
close(sd);
|
|
return ret;
|
|
}
|
|
|
|
return sd;
|
|
}
|