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diff --git a/man/systemd.dnssd.xml b/man/systemd.dnssd.xml new file mode 100644 index 0000000..5bf9375 --- /dev/null +++ b/man/systemd.dnssd.xml @@ -0,0 +1,241 @@ +<?xml version='1.0'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> +<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> + +<refentry id="systemd.dnssd" + xmlns:xi="http://www.w3.org/2001/XInclude" + conditional='ENABLE_RESOLVE'> + + <refentryinfo> + <title>systemd.dnssd</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>systemd.dnssd</refentrytitle> + <manvolnum>5</manvolnum> + </refmeta> + + <refnamediv> + <refname>systemd.dnssd</refname> + <refpurpose>DNS-SD configuration</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename><replaceable>network_service</replaceable>.dnssd</filename></para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>DNS-SD setup is performed by + <citerefentry><refentrytitle>systemd-resolved</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para> + + <para>The main network service file must have the extension <filename>.dnssd</filename>; other + extensions are ignored.</para> + + <para>The <filename>.dnssd</filename> files are read from the files located in the system network + directories <filename>/usr/lib/systemd/dnssd</filename> and + <filename>/usr/local/lib/systemd/dnssd</filename>, the volatile runtime network directory + <filename>/run/systemd/dnssd</filename> and the local administration network directory + <filename>/etc/systemd/dnssd</filename>. All configuration files are collectively sorted and processed in + lexical order, regardless of the directories in which they live. However, files with identical filenames + replace each other. Files in <filename>/etc/</filename> have the highest priority, files in + <filename>/run/</filename> take precedence over files with the same name in + <filename>/usr/lib/</filename>. This can be used to override a system-supplied configuration file with a + local file if needed.</para> + + <para>Along with the network service file <filename>foo.dnssd</filename>, a "drop-in" directory + <filename>foo.dnssd.d/</filename> may exist. All files with the suffix + <literal>.conf</literal> from this directory will be parsed after the file itself is + parsed. This is useful to alter or add configuration settings, without having to modify the main + configuration file. Each drop-in file must have appropriate section headers.</para> + + <para>In addition to <filename>/etc/systemd/dnssd</filename>, drop-in <literal>.d</literal> directories + can be placed in <filename>/usr/lib/systemd/dnssd</filename> or <filename>/run/systemd/dnssd</filename> + directories. Drop-in files in <filename>/etc/</filename> take precedence over those in + <filename>/run/</filename> which in turn take precedence over those in <filename>/usr/lib/</filename> or + <filename>/usr/local/lib</filename>. Drop-in files under any of these directories take precedence over + the main network service file wherever located.</para> + </refsect1> + + <refsect1> + <title>[Service] Section Options</title> + + <para>The network service file contains a [Service] + section, which specifies a discoverable network service announced in a + local network with Multicast DNS broadcasts.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Name=</varname></term> + <listitem> + <para>An instance name of the network service as defined in the section 4.1.1 of <ulink + url="https://tools.ietf.org/html/rfc6763">RFC 6763</ulink>, e.g. <literal>webserver</literal>.</para> + <para>The option supports simple specifier expansion. The following expansions are understood:</para> + <table class='specifiers'> + <title>Specifiers available</title> + <tgroup cols='3' align='left' colsep='1' rowsep='1'> + <colspec colname="spec" /> + <colspec colname="mean" /> + <colspec colname="detail" /> + <thead> + <row> + <entry>Specifier</entry> + <entry>Meaning</entry> + <entry>Details</entry> + </row> + </thead> + <tbody> + <xi:include href="standard-specifiers.xml" xpointer="a"/> + <xi:include href="standard-specifiers.xml" xpointer="A"/> + <xi:include href="standard-specifiers.xml" xpointer="b"/> + <xi:include href="standard-specifiers.xml" xpointer="B"/> + <xi:include href="standard-specifiers.xml" xpointer="H"/> + <xi:include href="standard-specifiers.xml" xpointer="m"/> + <xi:include href="standard-specifiers.xml" xpointer="M"/> + <xi:include href="standard-specifiers.xml" xpointer="o"/> + <xi:include href="standard-specifiers.xml" xpointer="v"/> + <xi:include href="standard-specifiers.xml" xpointer="w"/> + <xi:include href="standard-specifiers.xml" xpointer="W"/> + <xi:include href="standard-specifiers.xml" xpointer="percent"/> + </tbody> + </tgroup> + </table> + + <xi:include href="version-info.xml" xpointer="v236"/> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Type=</varname></term> + <listitem> + <para>A type of the network service as defined in the section 4.1.2 of <ulink + url="https://tools.ietf.org/html/rfc6763">RFC 6763</ulink>, e.g. <literal>_http._tcp</literal>. + </para> + + <xi:include href="version-info.xml" xpointer="v236"/> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Port=</varname></term> + <listitem> + <para>An IP port number of the network service.</para> + + <xi:include href="version-info.xml" xpointer="v236"/> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Priority=</varname></term> + <listitem> + <para>A priority number set in <constant class='dns'>SRV</constant> resource records corresponding + to the network service.</para> + + <xi:include href="version-info.xml" xpointer="v236"/> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Weight=</varname></term> + <listitem> + <para>A weight number set in <constant class='dns'>SRV</constant> resource records corresponding + to the network service.</para> + + <xi:include href="version-info.xml" xpointer="v236"/> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>TxtText=</varname></term> + <listitem> + <para>A whitespace-separated list of arbitrary key/value pairs + conveying additional information about the named service in the corresponding TXT resource record, + e.g. <literal>path=/portal/index.html</literal>. Keys and values can contain C-style escape + sequences which get translated upon reading configuration files. + </para> + <para>This option together with <varname>TxtData=</varname> may be specified more than once, in which + case multiple TXT resource records will be created for the service. If the empty string is assigned to + this option, the list is reset and all prior assignments will have no effect. + </para> + + <xi:include href="version-info.xml" xpointer="v236"/> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>TxtData=</varname></term> + <listitem> + <para>A whitespace-separated list of arbitrary key/value pairs + conveying additional information about the named service in the corresponding TXT resource record + where values are base64-encoded string representing any binary data, + e.g. <literal>data=YW55IGJpbmFyeSBkYXRhCg==</literal>. Keys can contain C-style escape + sequences which get translated upon reading configuration files. + </para> + <para>This option together with <varname>TxtText=</varname> may be specified more than once, in which + case multiple TXT resource records will be created for the service. If the empty string is assigned to + this option, the list is reset and all prior assignments will have no effect. + </para> + + <xi:include href="version-info.xml" xpointer="v236"/> + </listitem> + </varlistentry> + </variablelist> + + </refsect1> + + <refsect1> + <title>Examples</title> + <example> + <title>HTTP service</title> + + <programlisting># /etc/systemd/dnssd/http.dnssd +[Service] +Name=%H +Type=_http._tcp +Port=80 +TxtText=path=/stats/index.html t=temperature_sensor</programlisting> + + <para>This makes the http server running on the host discoverable in the local network + given MulticastDNS is enabled on the network interface.</para> + + <para>Now the utility <literal>resolvectl</literal> should be able to resolve the + service to the host's name:</para> + + <programlisting>$ resolvectl service meteo._http._tcp.local +meteo._http._tcp.local: meteo.local:80 [priority=0, weight=0] + 169.254.208.106%senp0s21f0u2u4 + fe80::213:3bff:fe49:8aa%senp0s21f0u2u4 + path=/stats/index.html + t=temperature_sensor + (meteo/_http._tcp/local) + +-- Information acquired via protocol mDNS/IPv6 in 4.0ms. +-- Data is authenticated: yes</programlisting> + + <para><literal>Avahi</literal> running on a different host in the same local network should see the service as well:</para> + + <programlisting>$ avahi-browse -a -r ++ enp3s0 IPv6 meteo Web Site local ++ enp3s0 IPv4 meteo Web Site local += enp3s0 IPv6 meteo Web Site local + hostname = [meteo.local] + address = [fe80::213:3bff:fe49:8aa] + port = [80] + txt = ["path=/stats/index.html" "t=temperature_sensor"] += enp3s0 IPv4 meteo Web Site local + hostname = [meteo.local] + address = [169.254.208.106] + port = [80] + txt = ["path=/stats/index.html" "t=temperature_sensor"]</programlisting> + + </example> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>resolvectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |