summaryrefslogtreecommitdiff
path: root/man/systemd.link.xml
blob: c1176ba1762fd70b1d8cc7850c8a13dfd0fb8d95 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
<?xml version='1.0'?> <!--*-nxml-*-->
<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
        "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<!--
  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/>.
-->

<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 <literal>net_setup_link</literal>
                udev builtin.</para>

                <para>The link files are read from the files located in the
                system network directory <filename>/usr/lib/systemd/network</filename>,
                the volatile runtime network directory <filename>/run/systemd/network</filename>
                and the local administration network directory <filename>/etc/systemd/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>/usr/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>/usr/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; and 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.</para>

                <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>Path=</varname></term>
                                <listitem>
                                <para>The persistent path, as exposed by the
                                udev property <literal>ID_PATH</literal>. May
                                contain shell style globs.</para>
                        </listitem>
                        </varlistentry>
                        <varlistentry>
                                <term><varname>Driver=</varname></term>
                                <listitem>
                                        <para>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>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>

                <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 this 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.</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.</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
                                        commandline. 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>. The available policies
                                        are:</para>

                                        <variablelist>
                                                <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>/etc/systemd/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>
                </para>
        </refsect1>

</refentry>