[thirdparty/systemd.git] / man / systemd.link.xml

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<!--
  This file is part of systemd.

  Copyright 2014 Tom Gundersen

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
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<refentry id="systemd.link">
  <refentryinfo>
    <title>systemd.link</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Tom</firstname>
        <surname>Gundersen</surname>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd.link</refentrytitle>
    <manvolnum>5</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd.link</refname>
    <refpurpose>Network device configuration</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><filename><replaceable>link</replaceable>.link</filename></para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>Network link configuration is performed by the
    <command>net_setup_link</command> udev builtin.</para>

    <para>The link files are read from the files located in the system
    network directory <filename>&rootlibexecdir;/network</filename>,
    the volatile runtime network directory
    <filename>/run/systemd/network</filename>, and the local
    administration network directory
    <filename>&pkgsysconfdir;/network</filename>. Link files must have
    the extension <filename>.link</filename>; other extensions are
    ignored. All link 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>&rootprefix;/lib</filename>. This can be used to
    override a system-supplied link file with a local file if needed;
    a symlink in <filename>/etc</filename> with the same name as a
    link file in <filename>&rootprefix;/lib</filename>, pointing to
    <filename>/dev/null</filename>, disables the link file
    entirely.</para>

    <para>The link file contains a <literal>[Match]</literal> section,
    which determines if a given link file may be applied to a given
    device, as well as a <literal>[Link]</literal> section specifying
    how the device should be configured. The first (in lexical order)
    of the link files that matches a given device is applied. Note
    that a default file <filename>99-default.link</filename> is
    shipped by the system, any user-supplied
    <filename>.link</filename> should hence have a lexically earlier
    name to be considered at all.</para>
  </refsect1>

  <refsect1>
    <title>[Match] Section Options</title>

    <para>A link file is said to match a device if each of the entries
    in the <literal>[Match]</literal> section matches, or if the
    section is empty. The following keys are accepted:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>MACAddress=</varname></term>
        <listitem>
          <para>The hardware address.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>OriginalName=</varname></term>
        <listitem>
          <para>A whitespace-separated list of shell-style globs matching
          the device name, as exposed by the udev property
          "INTERFACE". This can not be used to match on names that have
          already been changed from userspace. Caution is advised when matching on
          kernel-assigned names, as they are known to be unstable
          between reboots.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Path=</varname></term>
        <listitem>
          <para>A whitespace-separated list of shell-style globs matching
          the persistent path, as exposed by the udev property
          <literal>ID_PATH</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Driver=</varname></term>
        <listitem>
          <para>A whitespace-separated list of shell-style globs matching
          the driver currently bound to the device,
          as exposed by the udev property <literal>DRIVER</literal>
          of its parent device, or if that is not set, the
          driver as exposed by <literal>ethtool -i</literal>
          of the device itself.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Type=</varname></term>
        <listitem>
          <para>A whitespace-separated list of shell-style globs matching
          the device type, as exposed by the udev
          property <literal>DEVTYPE</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Host=</varname></term>
        <listitem>
          <para>Matches against the hostname or machine
          ID of the host. See <literal>ConditionHost=</literal> in
          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
          for details.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Virtualization=</varname></term>
        <listitem>
          <para>Checks whether the system is executed in
          a virtualized environment and optionally test
          whether it is a specific implementation. See
          <literal>ConditionVirtualization=</literal> in
          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
          for details.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>KernelCommandLine=</varname></term>
        <listitem>
          <para>Checks whether a specific kernel command line option
          is set (or if prefixed with the exclamation mark unset). See
          <literal>ConditionKernelCommandLine=</literal> in
          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
          for details.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Architecture=</varname></term>
        <listitem>
          <para>Checks whether the system is running on a specific
          architecture. See <literal>ConditionArchitecture=</literal>
          in
          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
          for details.</para>
        </listitem>
      </varlistentry>
    </variablelist>

  </refsect1>

  <refsect1>
    <title>[Link] Section Options</title>

    <para>The <literal>[Link]</literal> section accepts the following
    keys:</para>

    <variablelist class='network-directives'>
      <varlistentry>
        <term><varname>Description=</varname></term>
        <listitem>
          <para>A description of the device.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Alias=</varname></term>
        <listitem>
          <para>The <literal>ifalias</literal> is set to this
          value.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>MACAddressPolicy=</varname></term>
        <listitem>
          <para>The policy by which the MAC address should be set. The
          available policies are:
          </para>

          <variablelist>
            <varlistentry>
              <term><literal>persistent</literal></term>
              <listitem>
                <para>If the hardware has a persistent MAC address, as
                most hardware should, and if it is used by the kernel,
                nothing is done. Otherwise, a new MAC address is
                generated which is guaranteed to be the same on every
                boot for the given machine and the given device, but
                which is otherwise random. This feature depends on ID_NET_NAME_*
                properties existing for the link, on hardware where these
                properties are not set the generation of a persistent MAC address
                will fail.</para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><literal>random</literal></term>
              <listitem>
                <para>If the kernel is using a random MAC address,
                nothing is done. Otherwise, a new address is randomly
                generated each time the device appears, typically at
                boot. Either way the random address will have the
                <literal>unicast</literal> and
                <literal>locally administered</literal> bits set.</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>MACAddress=</varname></term>
        <listitem>
          <para>The MAC address to use, if no
          <literal>MACAddressPolicy=</literal>
          is specified.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>NamePolicy=</varname></term>
        <listitem>
          <para>An ordered, space-separated list of policies by which
          the interface name should be set.
          <literal>NamePolicy</literal> may be disabled by specifying
          <literal>net.ifnames=0</literal> on the kernel command line.
          Each of the policies may fail, and the first successful one
          is used. The name is not set directly, but is exported to
          udev as the property <literal>ID_NET_NAME</literal>, which
          is, by default, used by a udev rule to set
          <literal>NAME</literal>. If the name has already been set by
          userspace, no renaming is performed. The available policies
          are:</para>

          <variablelist>
            <varlistentry>
              <term><literal>kernel</literal></term>
              <listitem>
                <para>If the kernel claims that the name it has set
                for a device is predictable, then no renaming is
                performed.</para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><literal>database</literal></term>
              <listitem>
                <para>The name is set based on entries in the udev's
                Hardware Database with the key
                <literal>ID_NET_NAME_FROM_DATABASE</literal>.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><literal>onboard</literal></term>
              <listitem>
                <para>The name is set based on information given by
                the firmware for on-board devices, as exported by the
                udev property <literal>ID_NET_NAME_ONBOARD</literal>.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><literal>slot</literal></term>
              <listitem>
                <para>The name is set based on information given by
                the firmware for hot-plug devices, as exported by the
                udev property <literal>ID_NET_NAME_SLOT</literal>.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><literal>path</literal></term>
              <listitem>
                <para>The name is set based on the device's physical
                location, as exported by the udev property
                <literal>ID_NET_NAME_PATH</literal>.</para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><literal>mac</literal></term>
              <listitem>
                <para>The name is set based on the device's persistent
                MAC address, as exported by the udev property
                <literal>ID_NET_NAME_MAC</literal>.</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Name=</varname></term>
        <listitem>
          <para>The interface name to use in case all the
          policies specified in
          <varname>NamePolicy=</varname> fail, or in case
          <varname>NamePolicy=</varname> is missing or
          disabled.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>MTUBytes=</varname></term>
        <listitem>
          <para>The maximum transmission unit in bytes to set for the
          device. The usual suffixes K, M, G, are supported and are
          understood to the base of 1024.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>BitsPerSecond=</varname></term>
        <listitem>
          <para>The speed to set for the device, the value is rounded
          down to the nearest Mbps. The usual suffixes K, M, G, are
          supported and are understood to the base of 1000.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>Duplex=</varname></term>
        <listitem>
          <para>The duplex mode to set for the device. The accepted
          values are <literal>half</literal> and
          <literal>full</literal>.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>WakeOnLan=</varname></term>
        <listitem>
          <para>The Wake-on-LAN policy to set for the device. The
          supported values are:</para>

          <variablelist>
            <varlistentry>
              <term><literal>phy</literal></term>
              <listitem>
                <para>Wake on PHY activity.</para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><literal>magic</literal></term>
              <listitem>
                <para>Wake on receipt of a magic packet.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term><literal>off</literal></term>
              <listitem>
                <para>Never wake.</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Example</title>
    <example>
      <title>&pkgsysconfdir;/network/wireless.link</title>

      <programlisting>[Match]
MACAddress=12:34:56:78:9a:bc
Driver=brcmsmac
Path=pci-0000:02:00.0-*
Type=wlan
Virtualization=no
Host=my-laptop
Architecture=x86-64

[Link]
Name=wireless0
MTUBytes=1450
BitsPerSecond=10M
WakeOnLan=magic
MACAddress=cb:a9:87:65:43:21</programlisting>
    </example>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry>
        <refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>
    </para>
  </refsect1>

</refentry>
Commit	Line	Data
1ff28eae	1	<?xml version='1.0'?> <!---nxml--->
1ff28eae	2	<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
681eb9cf FB	3	"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
	4	<!ENTITY % entities SYSTEM "custom-entities.ent" >
	5	%entities;
	6	]>
1ff28eae TG	7
	8	<!--
	9	This file is part of systemd.
	10
	11	Copyright 2014 Tom Gundersen
	12
	13	systemd is free software; you can redistribute it and/or modify it
	14	under the terms of the GNU Lesser General Public License as published by
	15	the Free Software Foundation; either version 2.1 of the License, or
	16	(at your option) any later version.
	17
	18	systemd is distributed in the hope that it will be useful, but
	19	WITHOUT ANY WARRANTY; without even the implied warranty of
	20	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	21	Lesser General Public License for more details.
	22
	23	You should have received a copy of the GNU Lesser General Public License
	24	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	25	-->
	26
	27	<refentry id="systemd.link">
798d3a52 ZJS	28	<refentryinfo>
	29	<title>systemd.link</title>
	30	<productname>systemd</productname>
1ff28eae	31
798d3a52 ZJS	32	<authorgroup>
	33	<author>
	34	<contrib>Developer</contrib>
	35	<firstname>Tom</firstname>
	36	<surname>Gundersen</surname>
	37	</author>
	38	</authorgroup>
	39	</refentryinfo>
1ff28eae	40
798d3a52 ZJS	41	<refmeta>
	42	<refentrytitle>systemd.link</refentrytitle>
	43	<manvolnum>5</manvolnum>
	44	</refmeta>
1ff28eae	45
798d3a52 ZJS	46	<refnamediv>
	47	<refname>systemd.link</refname>
	48	<refpurpose>Network device configuration</refpurpose>
	49	</refnamediv>
1ff28eae	50
798d3a52 ZJS	51	<refsynopsisdiv>
	52	<para><filename><replaceable>link</replaceable>.link</filename></para>
	53	</refsynopsisdiv>
1ff28eae	54
798d3a52 ZJS	55	<refsect1>
798d3a52 ZJS	56	<title>Description</title>
1ff28eae	57
798d3a52 ZJS	58	<para>Network link configuration is performed by the
798d3a52 ZJS	59	<command>net_setup_link</command> udev builtin.</para>
1ff28eae	60
798d3a52	61	<para>The link files are read from the files located in the system
681eb9cf	62	network directory <filename>&rootlibexecdir;/network</filename>,
798d3a52 ZJS	63	the volatile runtime network directory
	64	<filename>/run/systemd/network</filename>, and the local
	65	administration network directory
681eb9cf	66	<filename>&pkgsysconfdir;/network</filename>. Link files must have
798d3a52 ZJS	67	the extension <filename>.link</filename>; other extensions are
	68	ignored. All link files are collectively sorted and processed in
	69	lexical order, regardless of the directories in which they live.
	70	However, files with identical filenames replace each other. Files
	71	in <filename>/etc</filename> have the highest priority, files in
	72	<filename>/run</filename> take precedence over files with the same
7d2e33a4	73	name in <filename>&rootprefix;/lib</filename>. This can be used to
798d3a52 ZJS	74	override a system-supplied link file with a local file if needed;
798d3a52 ZJS	75	a symlink in <filename>/etc</filename> with the same name as a
7d2e33a4	76	link file in <filename>&rootprefix;/lib</filename>, pointing to
798d3a52 ZJS	77	<filename>/dev/null</filename>, disables the link file
798d3a52 ZJS	78	entirely.</para>
1ff28eae	79
798d3a52 ZJS	80	<para>The link file contains a <literal>[Match]</literal> section,
	81	which determines if a given link file may be applied to a given
	82	device, as well as a <literal>[Link]</literal> section specifying
	83	how the device should be configured. The first (in lexical order)
	84	of the link files that matches a given device is applied. Note
	85	that a default file <filename>99-default.link</filename> is
	86	shipped by the system, any user-supplied
	87	<filename>.link</filename> should hence have a lexically earlier
	88	name to be considered at all.</para>
	89	</refsect1>
102bd40e	90
798d3a52 ZJS	91	<refsect1>
798d3a52 ZJS	92	<title>[Match] Section Options</title>
1ff28eae	93
798d3a52 ZJS	94	<para>A link file is said to match a device if each of the entries
	95	in the <literal>[Match]</literal> section matches, or if the
	96	section is empty. The following keys are accepted:</para>
1ff28eae	97
798d3a52 ZJS	98	<variablelist class='network-directives'>
	99	<varlistentry>
	100	<term><varname>MACAddress=</varname></term>
	101	<listitem>
	102	<para>The hardware address.</para>
	103	</listitem>
	104	</varlistentry>
	105	<varlistentry>
	106	<term><varname>OriginalName=</varname></term>
	107	<listitem>
5256e00e TG	108	<para>A whitespace-separated list of shell-style globs matching
	109	the device name, as exposed by the udev property
	110	"INTERFACE". This can not be used to match on names that have
	111	already been changed from userspace. Caution is advised when matching on
798d3a52 ZJS	112	kernel-assigned names, as they are known to be unstable
	113	between reboots.</para>
	114	</listitem>
	115	</varlistentry>
	116	<varlistentry>
	117	<term><varname>Path=</varname></term>
	118	<listitem>
5256e00e TG	119	<para>A whitespace-separated list of shell-style globs matching
	120	the persistent path, as exposed by the udev property
	121	<literal>ID_PATH</literal>.</para>
798d3a52 ZJS	122	</listitem>
	123	</varlistentry>
	124	<varlistentry>
	125	<term><varname>Driver=</varname></term>
	126	<listitem>
5256e00e TG	127	<para>A whitespace-separated list of shell-style globs matching
5256e00e TG	128	the driver currently bound to the device,
798d3a52 ZJS	129	as exposed by the udev property <literal>DRIVER</literal>
	130	of its parent device, or if that is not set, the
	131	driver as exposed by <literal>ethtool -i</literal>
	132	of the device itself.</para>
	133	</listitem>
	134	</varlistentry>
	135	<varlistentry>
	136	<term><varname>Type=</varname></term>
	137	<listitem>
5256e00e TG	138	<para>A whitespace-separated list of shell-style globs matching
5256e00e TG	139	the device type, as exposed by the udev
798d3a52 ZJS	140	property <literal>DEVTYPE</literal>.</para>
	141	</listitem>
	142	</varlistentry>
	143	<varlistentry>
	144	<term><varname>Host=</varname></term>
	145	<listitem>
	146	<para>Matches against the hostname or machine
	147	ID of the host. See <literal>ConditionHost=</literal> in
	148	<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
	149	for details.</para>
	150	</listitem>
	151	</varlistentry>
	152	<varlistentry>
	153	<term><varname>Virtualization=</varname></term>
	154	<listitem>
	155	<para>Checks whether the system is executed in
	156	a virtualized environment and optionally test
	157	whether it is a specific implementation. See
	158	<literal>ConditionVirtualization=</literal> in
	159	<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
	160	for details.</para>
	161	</listitem>
	162	</varlistentry>
	163	<varlistentry>
	164	<term><varname>KernelCommandLine=</varname></term>
	165	<listitem>
	166	<para>Checks whether a specific kernel command line option
	167	is set (or if prefixed with the exclamation mark unset). See
	168	<literal>ConditionKernelCommandLine=</literal> in
	169	<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
	170	for details.</para>
	171	</listitem>
	172	</varlistentry>
	173	<varlistentry>
	174	<term><varname>Architecture=</varname></term>
	175	<listitem>
	176	<para>Checks whether the system is running on a specific
	177	architecture. See <literal>ConditionArchitecture=</literal>
	178	in
	179	<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
	180	for details.</para>
	181	</listitem>
	182	</varlistentry>
	183	</variablelist>
1ff28eae	184
798d3a52	185	</refsect1>
102bd40e	186
798d3a52 ZJS	187	<refsect1>
798d3a52 ZJS	188	<title>[Link] Section Options</title>
102bd40e	189
798d3a52 ZJS	190	<para>The <literal>[Link]</literal> section accepts the following
798d3a52 ZJS	191	keys:</para>
1ff28eae	192
798d3a52 ZJS	193	<variablelist class='network-directives'>
	194	<varlistentry>
	195	<term><varname>Description=</varname></term>
	196	<listitem>
	197	<para>A description of the device.</para>
	198	</listitem>
	199	</varlistentry>
	200	<varlistentry>
	201	<term><varname>Alias=</varname></term>
	202	<listitem>
	203	<para>The <literal>ifalias</literal> is set to this
	204	value.</para>
	205	</listitem>
	206	</varlistentry>
	207	<varlistentry>
	208	<term><varname>MACAddressPolicy=</varname></term>
	209	<listitem>
	210	<para>The policy by which the MAC address should be set. The
	211	available policies are:
	212	</para>
1ff28eae	213
798d3a52 ZJS	214	<variablelist>
	215	<varlistentry>
	216	<term><literal>persistent</literal></term>
	217	<listitem>
	218	<para>If the hardware has a persistent MAC address, as
	219	most hardware should, and if it is used by the kernel,
	220	nothing is done. Otherwise, a new MAC address is
	221	generated which is guaranteed to be the same on every
	222	boot for the given machine and the given device, but
1c25683e TG	223	which is otherwise random. This feature depends on ID_NET_NAME_*
1c25683e TG	224	properties existing for the link, on hardware where these
e2acdb6b	225	properties are not set the generation of a persistent MAC address
1c25683e	226	will fail.</para>
798d3a52 ZJS	227	</listitem>
	228	</varlistentry>
	229	<varlistentry>
	230	<term><literal>random</literal></term>
	231	<listitem>
	232	<para>If the kernel is using a random MAC address,
	233	nothing is done. Otherwise, a new address is randomly
	234	generated each time the device appears, typically at
2e229e0c TG	235	boot. Either way the random address will have the
	236	<literal>unicast</literal> and
	237	<literal>locally administered</literal> bits set.</para>
798d3a52 ZJS	238	</listitem>
	239	</varlistentry>
	240	</variablelist>
	241	</listitem>
	242	</varlistentry>
	243	<varlistentry>
	244	<term><varname>MACAddress=</varname></term>
	245	<listitem>
	246	<para>The MAC address to use, if no
	247	<literal>MACAddressPolicy=</literal>
	248	is specified.</para>
	249	</listitem>
	250	</varlistentry>
	251	<varlistentry>
	252	<term><varname>NamePolicy=</varname></term>
	253	<listitem>
	254	<para>An ordered, space-separated list of policies by which
	255	the interface name should be set.
	256	<literal>NamePolicy</literal> may be disabled by specifying
	257	<literal>net.ifnames=0</literal> on the kernel command line.
	258	Each of the policies may fail, and the first successful one
	259	is used. The name is not set directly, but is exported to
	260	udev as the property <literal>ID_NET_NAME</literal>, which
	261	is, by default, used by a udev rule to set
	262	<literal>NAME</literal>. If the name has already been set by
	263	userspace, no renaming is performed. The available policies
	264	are:</para>
1ff28eae	265
798d3a52 ZJS	266	<variablelist>
	267	<varlistentry>
	268	<term><literal>kernel</literal></term>
	269	<listitem>
	270	<para>If the kernel claims that the name it has set
	271	for a device is predictable, then no renaming is
	272	performed.</para>
	273	</listitem>
	274	</varlistentry>
	275	<varlistentry>
	276	<term><literal>database</literal></term>
	277	<listitem>
	278	<para>The name is set based on entries in the udev's
	279	Hardware Database with the key
	280	<literal>ID_NET_NAME_FROM_DATABASE</literal>.
	281	</para>
	282	</listitem>
	283	</varlistentry>
	284	<varlistentry>
	285	<term><literal>onboard</literal></term>
	286	<listitem>
	287	<para>The name is set based on information given by
	288	the firmware for on-board devices, as exported by the
	289	udev property <literal>ID_NET_NAME_ONBOARD</literal>.
	290	</para>
	291	</listitem>
	292	</varlistentry>
	293	<varlistentry>
	294	<term><literal>slot</literal></term>
	295	<listitem>
	296	<para>The name is set based on information given by
	297	the firmware for hot-plug devices, as exported by the
	298	udev property <literal>ID_NET_NAME_SLOT</literal>.
	299	</para>
	300	</listitem>
	301	</varlistentry>
	302	<varlistentry>
	303	<term><literal>path</literal></term>
	304	<listitem>
	305	<para>The name is set based on the device's physical
	306	location, as exported by the udev property
	307	<literal>ID_NET_NAME_PATH</literal>.</para>
	308	</listitem>
	309	</varlistentry>
	310	<varlistentry>
	311	<term><literal>mac</literal></term>
	312	<listitem>
	313	<para>The name is set based on the device's persistent
	314	MAC address, as exported by the udev property
	315	<literal>ID_NET_NAME_MAC</literal>.</para>
	316	</listitem>
	317	</varlistentry>
	318	</variablelist>
	319	</listitem>
	320	</varlistentry>
	321	<varlistentry>
	322	<term><varname>Name=</varname></term>
	323	<listitem>
	324	<para>The interface name to use in case all the
	325	policies specified in
	326	<varname>NamePolicy=</varname> fail, or in case
	327	<varname>NamePolicy=</varname> is missing or
	328	disabled.</para>
	329	</listitem>
330	</varlistentry>
331	<varlistentry>
332	<term><varname>MTUBytes=</varname></term>
333	<listitem>
334	<para>The maximum transmission unit in bytes to set for the
335	device. The usual suffixes K, M, G, are supported and are
336	understood to the base of 1024.</para>
337	</listitem>
338	</varlistentry>
339	<varlistentry>
340	<term><varname>BitsPerSecond=</varname></term>
341	<listitem>
342	<para>The speed to set for the device, the value is rounded
343	down to the nearest Mbps. The usual suffixes K, M, G, are
344	supported and are understood to the base of 1000.</para>
345	</listitem>
346	</varlistentry>
347	<varlistentry>
348	<term><varname>Duplex=</varname></term>
349	<listitem>
350	<para>The duplex mode to set for the device. The accepted
351	values are <literal>half</literal> and
352	<literal>full</literal>.</para>
353	</listitem>
354	</varlistentry>
355	<varlistentry>
356	<term><varname>WakeOnLan=</varname></term>
357	<listitem>
358	<para>The Wake-on-LAN policy to set for the device. The
359	supported values are:</para>
1ff28eae	360
798d3a52 ZJS	361	<variablelist>
	362	<varlistentry>
	363	<term><literal>phy</literal></term>
	364	<listitem>
	365	<para>Wake on PHY activity.</para>
	366	</listitem>
	367	</varlistentry>
	368	<varlistentry>
	369	<term><literal>magic</literal></term>
	370	<listitem>
	371	<para>Wake on receipt of a magic packet.
	372	</para>
	373	</listitem>
	374	</varlistentry>
	375	<varlistentry>
	376	<term><literal>off</literal></term>
	377	<listitem>
	378	<para>Never wake.</para>
	379	</listitem>
	380	</varlistentry>
	381	</variablelist>
	382	</listitem>
	383	</varlistentry>
	384	</variablelist>
	385	</refsect1>
1ff28eae	386
798d3a52 ZJS	387	<refsect1>
	388	<title>Example</title>
	389	<example>
681eb9cf	390	<title>&pkgsysconfdir;/network/wireless.link</title>
1ff28eae	391
798d3a52	392	<programlisting>[Match]
7abaad1a	393	MACAddress=12:34:56:78:9a:bc
	394	Driver=brcmsmac
	395	Path=pci-0000:02:00.0-*
	396	Type=wlan
	397	Virtualization=no
	398	Host=my-laptop
	399	Architecture=x86-64
1ff28eae	400
7abaad1a	401	[Link]
	402	Name=wireless0
	403	MTUBytes=1450
	404	BitsPerSecond=10M
	405	WakeOnLan=magic
	406	MACAddress=cb:a9:87:65:43:21</programlisting>
798d3a52 ZJS	407	</example>
798d3a52 ZJS	408	</refsect1>
1ff28eae	409
798d3a52 ZJS	410	<refsect1>
	411	<title>See Also</title>
	412	<para>
	413	<citerefentry>
	414	<refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum>
	415	</citerefentry>,
	416	<citerefentry>
	417	<refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
	418	</citerefentry>,
	419	<citerefentry>
	420	<refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum>
	421	</citerefentry>,
	422	<citerefentry>
	423	<refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum>
	424	</citerefentry>
	425	</para>
	426	</refsect1>
1ff28eae TG	427
1ff28eae TG	428	</refentry>