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98 lines
3.3 KiB
98 lines
3.3 KiB
.\" |
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.\" Copyright 2010 by Ben Greear <greearb@candelatech.com> |
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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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.\" SPDX-License-Identifier: MIT |
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.\" |
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.TH ARES_SET_SERVERS_CSV 3 "5 Dec 2023" |
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.SH NAME |
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ares_set_servers_csv, ares_set_servers_ports_csv, ares_get_servers_csv \- Set |
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or Get a list of DNS servers used for queries. |
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.SH SYNOPSIS |
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.nf |
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#include <ares.h> |
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int ares_set_servers_csv(ares_channel_t *\fIchannel\fP, const char* \fIservers\fP) |
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int ares_set_servers_ports_csv(ares_channel_t *\fIchannel\fP, const char* \fIservers\fP) |
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char *ares_get_servers_csv(ares_channel_t *\fIchannel\fP) |
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.fi |
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.SH DESCRIPTION |
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The \fBares_set_servers_csv\fP and \fBares_set_servers_ports_csv\fP functions set |
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the list of DNS servers that c-ares will query. As of v1.22.0 this function can |
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be called on an active channel with running queries, previously it would return |
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ARES_ENOTIMP. |
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Though not recommended, passing NULL for servers will clear all configured |
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servers and make an inoperable channel, this may be advantageous for test |
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simulation but unlikely to be useful in production. |
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The \fBares_get_servers_csv\fP retrieves the list of servers in comma delimited |
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format. |
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The input and output format is a comma separated list of servers. Each server |
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entry may contain these forms: |
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ip[:port][%iface] |
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The \fBip\fP may be encapsulated in square brackets ([ ]), and must be if |
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using ipv6 and also specifying a port. |
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The \fBport\fP is optional, and will default to 53 or the value specified in |
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\fBares_init_options(3)\fP. |
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The \fBiface\fP is specific to IPv6 link-local servers (fe80::/10) and should |
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not otherwise be used. |
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For example: |
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192.168.1.100,192.168.1.101:53,[1:2:3::4]:53,[fe80::1]:53%eth0 |
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.PP |
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As of c-ares 1.24.0, \fBares_set_servers_csv\fP and \fBares_set_servers_ports_csv\fP |
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are identical. Prior versions would simply omit ports in \fBares_set_servers_csv\fP |
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but due to the addition of link local interface support, this difference was |
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removed. |
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.SH RETURN VALUES |
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.B ares_set_servers_csv(3) |
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and |
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.B ares_set_servers_ports_csv(3) |
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may return any of the following values: |
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.TP 15 |
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.B ARES_SUCCESS |
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The name servers configuration was successfully initialized. |
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.TP 15 |
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.B ARES_ENOMEM |
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The process's available memory was exhausted. |
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.TP 15 |
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.B ARES_ENODATA |
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The channel data identified by |
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.IR channel |
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was invalid. |
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.TP 15 |
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.B ARES_ENOTINITIALIZED |
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c-ares library initialization not yet performed. |
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.PP |
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.B ares_get_servers_csv(3) |
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returns a string representing the servers configured which must be freed with |
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\fBares_free_string(3)\fP. If it returns NULL, this is an out of memory condition. |
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.SH SEE ALSO |
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.BR ares_set_servers (3) |
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.SH AVAILABILITY |
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\fBares_set_servers_csv\fP was added in c-ares 1.7.2 |
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\fBares_set_servers_ports_csv\fP was added in c-ares 1.11.0. |
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\fBares_get_servers_csv\fP was added in c-ares 1.24.0. |
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.SH AUTHOR |
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Ben Greear
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