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diff --git a/man5/gai.conf.5 b/man5/gai.conf.5 new file mode 100644 index 0000000..bba4480 --- /dev/null +++ b/man5/gai.conf.5 @@ -0,0 +1,89 @@ +.\" Copyright (C) 2006 Red Hat, Inc. All rights reserved. +.\" Author: Ulrich Drepper <drepper@redhat.com> +.\" +.\" SPDX-License-Identifier: GPL-2.0-only +.\" +.TH gai.conf 5 2023-02-05 "Linux man-pages 6.05.01" +.SH NAME +gai.conf \- getaddrinfo(3) configuration file +.SH DESCRIPTION +A call to +.BR getaddrinfo (3) +might return multiple answers. +According to RFC\ 3484 these answers must be sorted so that +the answer with the highest success rate is first in the list. +The RFC provides an algorithm for the sorting. +The static rules are not always adequate, though. +For this reason, +the RFC also requires that system administrators should have the possibility +to dynamically change the sorting. +For the glibc implementation, this can be achieved with the +.I /etc/gai.conf +file. +.PP +Each line in the configuration file consists of a keyword and its parameters. +White spaces in any place are ignored. +Lines starting with \[aq]#\[aq] are comments and are ignored. +.PP +The keywords currently recognized are: +.TP +\fBlabel\fR \fInetmask\fR \fIprecedence\fR +The value is added to the label table used in the RFC\ 3484 sorting. +If any \fBlabel\fR definition is present in the configuration file, +the default table is not used. +All the label definitions +of the default table which are to be maintained have to be duplicated. +Following the keyword, +the line has to contain a network mask and a precedence value. +.TP +\fBprecedence\fR \fInetmask\fR \fIprecedence\fR +This keyword is similar to \fBlabel\fR, but instead the value is added +to the precedence table as specified in RFC\ 3484. +Once again, the +presence of a single \fBprecedence\fR line in the configuration file +causes the default table to not be used. +.TP +\fBreload\fR <\fByes\fR|\fBno\fR> +This keyword controls whether a process checks whether the configuration +file has been changed since the last time it was read. +If the value is +"\fByes\fR", the file is reread. +This might cause problems in multithreaded +applications and is generally a bad idea. +The default is "\fBno\fR". +.TP +\fBscopev4\fR \fImask\fR \fIvalue\fR +Add another rule to the RFC\ 3484 scope table for IPv4 address. +By default, the scope IDs described in section 3.2 in RFC\ 3438 are used. +Changing these defaults should hardly ever be necessary. +.SH FILES +\fI/etc/gai.conf\fR +.SH VERSIONS +The +.I gai.conf +.\" Added in 2006 +file is supported since glibc 2.5. +.SH EXAMPLES +The default table according to RFC\ 3484 would be specified with the +following configuration file: +.PP +.in +4n +.EX +label ::1/128 0 +label ::/0 1 +label 2002::/16 2 +label ::/96 3 +label ::ffff:0:0/96 4 +precedence ::1/128 50 +precedence ::/0 40 +precedence 2002::/16 30 +precedence ::/96 20 +precedence ::ffff:0:0/96 10 +.EE +.in +.\" .SH AUTHOR +.\" Ulrich Drepper <drepper@redhat.com> +.\" +.SH SEE ALSO +.BR getaddrinfo (3), +RFC\ 3484 |