mirror of
https://github.com/moparisthebest/curl
synced 2024-12-25 09:38:54 -05:00
d95f3dc0b1
This patch adds CURLOPT_DNS_SHUFFLE_ADDRESSES to explicitly request shuffling of IP addresses returned for a hostname when there is more than one. This is useful when the application knows that a round robin approach is appropriate and is willing to accept the consequences of potentially discarding some preference order returned by the system's implementation. Closes #1694
70 lines
2.7 KiB
Groff
70 lines
2.7 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * Project ___| | | | _ \| |
|
|
.\" * / __| | | | |_) | |
|
|
.\" * | (__| |_| | _ <| |___
|
|
.\" * \___|\___/|_| \_\_____|
|
|
.\" *
|
|
.\" * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
|
|
.\" *
|
|
.\" * This software is licensed as described in the file COPYING, which
|
|
.\" * you should have received as part of this distribution. The terms
|
|
.\" * are also available at https://curl.haxx.se/docs/copyright.html.
|
|
.\" *
|
|
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
|
|
.\" * copies of the Software, and permit persons to whom the Software is
|
|
.\" * furnished to do so, under the terms of the COPYING file.
|
|
.\" *
|
|
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
|
.\" * KIND, either express or implied.
|
|
.\" *
|
|
.\" **************************************************************************
|
|
.\"
|
|
.TH CURLOPT_DNS_SHUFFLE_ADDRESSES 3 "3 March 2018" "libcurl 7.60.0" "curl_easy_setopt options"
|
|
.SH NAME
|
|
CURLOPT_DNS_SHUFFLE_ADDRESSES \- Shuffle addresses when a hostname returns more than one
|
|
.SH SYNOPSIS
|
|
.nf
|
|
#include <curl/curl.h>
|
|
|
|
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_SHUFFLE_ADDRESSES, long onoff);
|
|
.fi
|
|
.SH DESCRIPTION
|
|
When a name is resolved and more than one IP address is returned, shuffle the
|
|
order of all returned addresses so that they will be used in a random order.
|
|
This is similar to the ordering behavior of gethostbyname which is no longer
|
|
used on most platforms.
|
|
|
|
Addresses will not be reshuffled if a name resolution is completed using the
|
|
DNS cache. \fICURLOPT_DNS_CACHE_TIMEOUT(3)\fP can be used together with this
|
|
option to reduce DNS cache timeout or disable caching entirely if frequent
|
|
reshuffling is needed.
|
|
|
|
Since the addresses returned will be reordered randomly, their order will not
|
|
be in accordance with RFC 3484 or any other deterministic order that may be
|
|
generated by the system's name resolution implementation. This may have
|
|
performance impacts and may cause IPv4 to be used before IPv6 or vice versa.
|
|
.SH DEFAULT
|
|
0 (disabled)
|
|
.SH PROTOCOLS
|
|
All
|
|
.SH EXAMPLE
|
|
.nf
|
|
CURL *curl = curl_easy_init();
|
|
if(curl) {
|
|
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
|
|
curl_easy_setopt(curl, CURLOPT_DNS_SHUFFLE_ADDRESSES, 1L);
|
|
|
|
curl_easy_perform(curl);
|
|
|
|
/* always cleanup */
|
|
curl_easy_cleanup(curl);
|
|
}
|
|
.fi
|
|
.SH AVAILABILITY
|
|
Added in 7.60.0
|
|
.SH RETURN VALUE
|
|
CURLE_OK or an error such as CURLE_UNKNOWN_OPTION.
|
|
.SH "SEE ALSO"
|
|
.BR CURLOPT_DNS_CACHE_TIMEOUT "(3), " CURLOPT_IPRESOLVE "(3), "
|