man/systemd.link.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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   5
   6 <refentry id="systemd.link">
   7   <refentryinfo>
   8     <title>systemd.link</title>
   9     <productname>systemd</productname>
  10   </refentryinfo>
  11
  12   <refmeta>
  13     <refentrytitle>systemd.link</refentrytitle>
  14     <manvolnum>5</manvolnum>
  15   </refmeta>
  16
  17   <refnamediv>
  18     <refname>systemd.link</refname>
  19     <refpurpose>Network device configuration</refpurpose>
  20   </refnamediv>
  21
  22   <refsynopsisdiv>
  23     <para><filename><replaceable>link</replaceable>.link</filename></para>
  24   </refsynopsisdiv>
  25
  26   <refsect1>
  27     <title>Description</title>
  28
  29     <para>A plain ini-style text file that encodes configuration for matching network devices, used by
  30     <citerefentry><refentrytitle>systemd-udevd</refentrytitle><manvolnum>8</manvolnum></citerefentry> and in
  31     particular its <command>net_setup_link</command> builtin. See
  32     <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>7</manvolnum></citerefentry> for a
  33     general description of the syntax.</para>
  34
  35     <para>The <filename>.link</filename> files are read from the files located in the system network
  36     directory <filename>/usr/lib/systemd/network</filename> and
  37     <filename>/usr/local/lib/systemd/network</filename>, the volatile runtime network directory
  38     <filename>/run/systemd/network</filename>, and the local administration network directory
  39     <filename>/etc/systemd/network</filename>. All configuration files are collectively sorted and
  40     processed in alphanumeric order, regardless of the directories in which they live. However, files
  41     with identical filenames replace each other. It is recommended that each filename is prefixed with
  42     a number (e.g. <filename>10-eth0.link</filename>). Otherwise, the default
  43     <filename>.link</filename> files or those generated by
  44     <citerefentry><refentrytitle>systemd-network-generator.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  45     may take precedence over user configured files. Files in <filename>/etc/</filename> have the
  46     highest priority, files in <filename>/run/</filename> take precedence over files with the same name
  47     in <filename>/usr/lib/</filename>. This can be used to override a system-supplied link file with a
  48     local file if needed. As a special case, an empty file (file size 0) or symlink with the same name
  49     pointing to <filename>/dev/null</filename> disables the configuration file entirely (it is
  50     "masked").</para>
  51
  52     <para>Along with the link file <filename>foo.link</filename>, a "drop-in" directory
  53     <filename>foo.link.d/</filename> may exist. All files with the suffix <literal>.conf</literal>
  54     from this directory will be merged in the alphanumeric order and parsed after the main file itself
  55     has been parsed. This is useful to alter or add configuration settings, without having to modify
  56     the main configuration file. Each drop-in file must have appropriate section headers.</para>
  57
  58     <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal>
  59     directories can be placed in <filename>/usr/lib/systemd/network</filename> or
  60     <filename>/run/systemd/network</filename> directories. Drop-in files in <filename>/etc/</filename>
  61     take precedence over those in <filename>/run/</filename> which in turn take precedence over those
  62     in <filename>/usr/lib/</filename>. Drop-in files under any of these directories take precedence
  63     over the main link file wherever located.</para>
  64
  65     <para>The link file contains a [Match] section, which determines if a given link file may be applied to a
  66     given device, as well as a [Link] section specifying how the device should be configured. The first (in
  67     lexical order) of the link files that matches a given device is applied. Note that a default file
  68     <filename>99-default.link</filename> is shipped by the system. Any user-supplied
  69     <filename>.link</filename> should hence have a lexically earlier name to be considered at all.</para>
  70
  71     <para>See <citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry> for
  72     diagnosing problems with <filename>.link</filename> files.</para>
  73   </refsect1>
  74
  75   <refsect1>
  76     <title>[Match] Section Options</title>
  77
  78     <para>A link file is said to match an interface if all matches specified by the [Match] section are
  79     satisfied. When a link file does not contain valid settings in [Match] section, then the file will
  80     match all interfaces and <command>systemd-udevd</command> warns about that. Hint: to avoid the
  81     warning and to make it clear that all interfaces shall be matched, add the following:
  82     <programlisting>OriginalName=*</programlisting>
  83     The first (in alphanumeric order) of the link files that matches a given interface is applied, all
  84     later files are ignored, even if they match as well. The following keys are accepted:</para>
  85
  86     <variablelist class='network-directives'>
  87       <!-- This list is reused in systemd.network(3), hence maintain a specific order:
  88            1. device matches shared between the two lists
  89            2. non-shared settings
  90            3. host matches shared between the two lists
  91         -->
  92
  93       <varlistentry id='mac-address'>
  94         <term><varname>MACAddress=</varname></term>
  95         <listitem>
  96           <para>A whitespace-separated list of hardware addresses. The acceptable formats are:</para>
  97
  98           <variablelist>
  99             <varlistentry>
 100               <term><option>colon-delimited hexadecimal</option></term>
 101               <listitem><para>
 102                 Each field must be one byte.
 103                 E.g. <literal>12:34:56:78:90:ab</literal> or <literal>AA:BB:CC:DD:EE:FF</literal>.
 104               </para></listitem>
 105             </varlistentry>
 106             <varlistentry>
 107               <term><option>hyphen-delimited hexadecimal</option></term>
 108               <listitem><para>
 109                 Each field must be one byte.
 110                 E.g. <literal>12-34-56-78-90-ab</literal> or <literal>AA-BB-CC-DD-EE-FF</literal>.
 111               </para></listitem>
 112             </varlistentry>
 113             <varlistentry>
 114               <term><option>dot-delimited hexadecimal</option></term>
 115               <listitem><para>
 116                 Each field must be two bytes.
 117                 E.g. <literal>1234.5678.90ab</literal> or <literal>AABB.CCDD.EEFF</literal>.
 118               </para></listitem>
 119             </varlistentry>
 120             <varlistentry>
 121               <term><option>IPv4 address format</option></term>
 122               <listitem><para>
 123                 E.g. <literal>127.0.0.1</literal> or <literal>192.168.0.1</literal>.
 124               </para></listitem>
 125             </varlistentry>
 126             <varlistentry>
 127               <term><option>IPv6 address format</option></term>
 128               <listitem><para>
 129                 E.g. <literal>2001:0db8:85a3::8a2e:0370:7334</literal> or <literal>::1</literal>.
 130               </para></listitem>
 131             </varlistentry>
 132           </variablelist>
 133
 134           <para>The total length of each MAC address must be 4 (for IPv4 tunnel), 6 (for Ethernet), 16
 135           (for IPv6 tunnel), or 20 (for InfiniBand). This option may appear more than once, in which
 136           case the lists are merged. If the empty string is assigned to this option, the list of
 137           hardware addresses defined prior to this is reset. Defaults to unset.</para>
 138         </listitem>
 139       </varlistentry>
 140
 141       <varlistentry id='permanent-mac-address'>
 142         <term><varname>PermanentMACAddress=</varname></term>
 143         <listitem>
 144           <para>A whitespace-separated list of hardware's permanent addresses. While
 145           <varname>MACAddress=</varname> matches the device's current MAC address, this matches the
 146           device's permanent MAC address, which may be different from the current one. Use full
 147           colon-, hyphen- or dot-delimited hexadecimal, or IPv4 or IPv6 address format. This option may
 148           appear more than once, in which case the lists are merged. If the empty string is assigned to
 149           this option, the list of hardware addresses defined prior to this is reset. Defaults to
 150           unset.</para>
 151         </listitem>
 152       </varlistentry>
 153
 154       <varlistentry id='path'>
 155         <term><varname>Path=</varname></term>
 156         <listitem>
 157           <para>A whitespace-separated list of shell-style globs matching
 158           the persistent path, as exposed by the udev property
 159           <varname>ID_PATH</varname>.</para>
 160         </listitem>
 161       </varlistentry>
 162
 163       <varlistentry id='driver'>
 164         <term><varname>Driver=</varname></term>
 165         <listitem>
 166           <para>A whitespace-separated list of shell-style globs matching the driver currently bound to the
 167           device, as exposed by the udev property <varname>ID_NET_DRIVER</varname> of its parent device, or
 168           if that is not set, the driver as exposed by <command>ethtool -i</command> of the device itself.
 169           If the list is prefixed with a "!", the test is inverted.</para>
 170         </listitem>
 171       </varlistentry>
 172
 173       <varlistentry id='type'>
 174         <term><varname>Type=</varname></term>
 175         <listitem>
 176           <para>A whitespace-separated list of shell-style globs matching the device type, as exposed by
 177           <command>networkctl list</command>. If the list is prefixed with a "!", the test is inverted.
 178           Some valid values are <literal>ether</literal>, <literal>loopback</literal>, <literal>wlan</literal>, <literal>wwan</literal>.
 179           Valid types are named either from the udev <literal>DEVTYPE</literal> attribute, or
 180           <literal>ARPHRD_</literal> macros in <filename>linux/if_arp.h</filename>, so this is not comprehensive.
 181           </para>
 182         </listitem>
 183       </varlistentry>
 184
 185       <varlistentry id='kind'>
 186         <term><varname>Kind=</varname></term>
 187         <listitem>
 188           <para>A whitespace-separated list of shell-style globs matching the device kind, as exposed by
 189           <command>networkctl status <replaceable>INTERFACE</replaceable></command> or
 190           <command>ip -d link show <replaceable>INTERFACE</replaceable></command>. If the list is
 191           prefixed with a "!", the test is inverted. Some valid values are <literal>bond</literal>,
 192           <literal>bridge</literal>, <literal>gre</literal>, <literal>tun</literal>,
 193           <literal>veth</literal>. Valid kinds are given by netlink's <literal>IFLA_INFO_KIND</literal>
 194           attribute, so this is not comprehensive.
 195           </para>
 196         </listitem>
 197       </varlistentry>
 198
 199       <varlistentry id='property'>
 200         <term><varname>Property=</varname></term>
 201         <listitem>
 202           <para>A whitespace-separated list of udev property names with their values after equals sign
 203           (<literal>=</literal>). If multiple properties are specified, the test results are ANDed.
 204           If the list is prefixed with a "!", the test is inverted. If a value contains white
 205           spaces, then please quote whole key and value pair. If a value contains quotation, then
 206           please escape the quotation with <literal>\</literal>.</para>
 207
 208           <para>Example: if a .link file has the following:
 209           <programlisting>Property=ID_MODEL_ID=9999 "ID_VENDOR_FROM_DATABASE=vendor name" "KEY=with \"quotation\""</programlisting>
 210           then, the .link file matches only when an interface has all the above three properties.
 211           </para>
 212         </listitem>
 213       </varlistentry>
 214
 215       <varlistentry>
 216         <term><varname>OriginalName=</varname></term>
 217         <listitem>
 218           <para>A whitespace-separated list of shell-style globs matching the device name, as exposed by the
 219           udev property "INTERFACE". This cannot be used to match on names that have already been changed
 220           from userspace. Caution is advised when matching on kernel-assigned names, as they are known to be
 221           unstable between reboots.</para>
 222         </listitem>
 223       </varlistentry>
 224
 225       <varlistentry id='host'>
 226         <term><varname>Host=</varname></term>
 227         <listitem>
 228           <para>Matches against the hostname or machine ID of the host. See <varname>ConditionHost=</varname> in
 229           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 230           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 231           If an empty string is assigned, the previously assigned value is cleared.
 232           </para>
 233         </listitem>
 234       </varlistentry>
 235
 236       <varlistentry id='virtualization'>
 237         <term><varname>Virtualization=</varname></term>
 238         <listitem>
 239           <para>Checks whether the system is executed in a virtualized environment and optionally test
 240           whether it is a specific implementation. See <varname>ConditionVirtualization=</varname> in
 241           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 242           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 243           If an empty string is assigned, the previously assigned value is cleared.
 244           </para>
 245         </listitem>
 246       </varlistentry>
 247
 248       <varlistentry id='kernel-command-line'>
 249         <term><varname>KernelCommandLine=</varname></term>
 250         <listitem>
 251           <para>Checks whether a specific kernel command line option is set. See
 252           <varname>ConditionKernelCommandLine=</varname> in
 253           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 254           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 255           If an empty string is assigned, the previously assigned value is cleared.
 256           </para>
 257         </listitem>
 258       </varlistentry>
 259
 260       <varlistentry id='kernel-version'>
 261         <term><varname>KernelVersion=</varname></term>
 262         <listitem>
 263           <para>Checks whether the kernel version (as reported by <command>uname -r</command>) matches a certain
 264           expression. See <varname>ConditionKernelVersion=</varname> in
 265           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
 266           details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 267           If an empty string is assigned, the previously assigned value is cleared.
 268           </para>
 269         </listitem>
 270       </varlistentry>
 271
 272       <varlistentry id='credential'>
 273         <term><varname>Credential=</varname></term>
 274         <listitem>
 275           <para>Checks whether the specified credential was passed to the
 276           <filename>systemd-networkd.service</filename> service. See <ulink
 277           url="https://systemd.io/CREDENTIALS">System and Service Credentials</ulink> for details. When
 278           prefixed with an exclamation mark (<literal>!</literal>), the result is negated.  If an empty
 279           string is assigned, the previously assigned value is cleared.
 280           </para>
 281         </listitem>
 282       </varlistentry>
 283
 284       <varlistentry id='architecture'>
 285         <term><varname>Architecture=</varname></term>
 286         <listitem>
 287           <para>Checks whether the system is running on a specific architecture. See
 288           <varname>ConditionArchitecture=</varname> in
 289           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 290           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 291           If an empty string is assigned, the previously assigned value is cleared.
 292           </para>
 293         </listitem>
 294       </varlistentry>
 295
 296       <varlistentry id='firmware'>
 297         <term><varname>Firmware=</varname></term>
 298         <listitem>
 299           <para>Checks whether the system is running on a machine with the specified firmware. See
 300           <varname>ConditionFirmware=</varname> in
 301           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 302           for details. When prefixed with an exclamation mark (<literal>!</literal>), the result is negated.
 303           If an empty string is assigned, the previously assigned value is cleared.
 304           </para>
 305         </listitem>
 306       </varlistentry>
 307     </variablelist>
 308
 309   </refsect1>
 310
 311   <refsect1>
 312     <title>[Link] Section Options</title>
 313
 314     <para>The [Link] section accepts the following
 315     keys:</para>
 316
 317     <variablelist class='network-directives'>
 318       <varlistentry>
 319         <term><varname>Description=</varname></term>
 320         <listitem>
 321           <para>A description of the device.</para>
 322         </listitem>
 323       </varlistentry>
 324       <varlistentry>
 325         <term><varname>Alias=</varname></term>
 326         <listitem>
 327           <para>The <varname>ifalias</varname> interface property is set to this value.</para>
 328         </listitem>
 329       </varlistentry>
 330       <varlistentry>
 331         <term><varname>MACAddressPolicy=</varname></term>
 332         <listitem>
 333           <para>The policy by which the MAC address should be set. The
 334           available policies are:
 335           </para>
 336
 337           <variablelist>
 338             <varlistentry>
 339               <term><option>persistent</option></term>
 340               <listitem>
 341                 <para>If the hardware has a persistent MAC address, as
 342                 most hardware should, and if it is used by the kernel,
 343                 nothing is done. Otherwise, a new MAC address is
 344                 generated which is guaranteed to be the same on every
 345                 boot for the given machine and the given device, but
 346                 which is otherwise random. This feature depends on ID_NET_NAME_*
 347                 properties to exist for the link. On hardware where these
 348                 properties are not set, the generation of a persistent MAC address
 349                 will fail.</para>
 350               </listitem>
 351             </varlistentry>
 352             <varlistentry>
 353               <term><option>random</option></term>
 354               <listitem>
 355                 <para>If the kernel is using a random MAC address,
 356                 nothing is done. Otherwise, a new address is randomly
 357                 generated each time the device appears, typically at
 358                 boot. Either way, the random address will have the
 359                 <literal>unicast</literal> and
 360                 <literal>locally administered</literal> bits set.</para>
 361               </listitem>
 362             </varlistentry>
 363             <varlistentry>
 364               <term><option>none</option></term>
 365               <listitem>
 366                 <para>Keeps the MAC address assigned by the kernel. Or use the MAC address specified in
 367                 <varname>MACAddress=</varname>.</para>
 368               </listitem>
 369             </varlistentry>
 370           </variablelist>
 371
 372           <para>An empty string assignment is equivalent to setting <literal>none</literal>.</para>
 373         </listitem>
 374       </varlistentry>
 375       <varlistentry>
 376         <term><varname>MACAddress=</varname></term>
 377         <listitem>
 378           <para>The interface MAC address to use. For this setting to take effect,
 379           <varname>MACAddressPolicy=</varname> must either be unset, empty, or <literal>none</literal>.
 380           </para>
 381         </listitem>
 382       </varlistentry>
 383       <varlistentry>
 384         <term><varname>NamePolicy=</varname></term>
 385         <listitem>
 386           <para>An ordered, space-separated list of policies by which the interface name should be set.
 387           <varname>NamePolicy=</varname> may be disabled by specifying <option>net.ifnames=0</option> on the
 388           kernel command line. Each of the policies may fail, and the first successful one is used. The name
 389           is not set directly, but is exported to udev as the property <option>ID_NET_NAME</option>, which
 390           is, by default, used by a
 391           <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 392           rule to set <varname>NAME</varname>. The available policies are:
 393           </para>
 394
 395           <variablelist>
 396             <varlistentry>
 397               <term><option>kernel</option></term>
 398               <listitem>
 399                 <para>If the kernel claims that the name it has set
 400                 for a device is predictable, then no renaming is
 401                 performed.</para>
 402               </listitem>
 403             </varlistentry>
 404             <varlistentry>
 405               <term><option>database</option></term>
 406               <listitem>
 407                 <para>The name is set based on entries in the udev's
 408                 Hardware Database with the key
 409                 <varname>ID_NET_NAME_FROM_DATABASE</varname>.
 410                 </para>
 411               </listitem>
 412             </varlistentry>
 413             <varlistentry>
 414               <term><option>onboard</option></term>
 415               <listitem>
 416                 <para>The name is set based on information given by
 417                 the firmware for on-board devices, as exported by the
 418                 udev property <varname>ID_NET_NAME_ONBOARD</varname>.
 419                 See <citerefentry><refentrytitle>systemd.net-naming-scheme</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 420                 </para>
 421               </listitem>
 422             </varlistentry>
 423             <varlistentry>
 424               <term><option>slot</option></term>
 425               <listitem>
 426                 <para>The name is set based on information given by
 427                 the firmware for hot-plug devices, as exported by the
 428                 udev property <varname>ID_NET_NAME_SLOT</varname>.
 429                 See <citerefentry><refentrytitle>systemd.net-naming-scheme</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 430                 </para>
 431               </listitem>
 432             </varlistentry>
 433             <varlistentry>
 434               <term><option>path</option></term>
 435               <listitem>
 436                 <para>The name is set based on the device's physical
 437                 location, as exported by the udev property
 438                 <varname>ID_NET_NAME_PATH</varname>.
 439                 See <citerefentry><refentrytitle>systemd.net-naming-scheme</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 440                 </para>
 441               </listitem>
 442             </varlistentry>
 443             <varlistentry>
 444               <term><option>mac</option></term>
 445               <listitem>
 446                 <para>The name is set based on the device's persistent
 447                 MAC address, as exported by the udev property
 448                 <varname>ID_NET_NAME_MAC</varname>.
 449                 See <citerefentry><refentrytitle>systemd.net-naming-scheme</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 450                 </para>
 451               </listitem>
 452             </varlistentry>
 453             <varlistentry>
 454               <term><option>keep</option></term>
 455               <listitem>
 456                 <para>If the device already had a name given by userspace (as part of creation of the device
 457                 or a rename), keep it.</para>
 458               </listitem>
 459             </varlistentry>
 460           </variablelist>
 461         </listitem>
 462       </varlistentry>
 463       <varlistentry>
 464         <term><varname>Name=</varname></term>
 465         <listitem>
 466           <para>The interface name to use. This option has lower precedence than
 467           <varname>NamePolicy=</varname>, so for this setting to take effect, <varname>NamePolicy=</varname>
 468           must either be unset, empty, disabled, or all policies configured there must fail. Also see the
 469           example below with <literal>Name=dmz0</literal>.</para>
 470
 471           <para>Note that specifying a name that the kernel might use for another
 472           interface (for example <literal>eth0</literal>) is dangerous because the
 473           name assignment done by udev will race with the assignment done by the
 474           kernel, and only one interface may use the name. Depending on the order of
 475           operations, either udev or the kernel will win, making the naming
 476           unpredictable. It is best to use some different prefix, for example
 477           <literal>internal0</literal>/<literal>external0</literal> or
 478           <literal>lan0</literal>/<literal>lan1</literal>/<literal>lan3</literal>.
 479           </para>
 480         </listitem>
 481       </varlistentry>
 482       <varlistentry>
 483         <term><varname>AlternativeNamesPolicy=</varname></term>
 484         <listitem>
 485           <para>A space-separated list of policies by which the interface's alternative names
 486           should be set. Each of the policies may fail, and all successful policies are used. The
 487           available policies are <literal>database</literal>, <literal>onboard</literal>,
 488           <literal>slot</literal>, <literal>path</literal>, and <literal>mac</literal>. If the
 489           kernel does not support the alternative names, then this setting will be ignored.
 490           </para>
 491         </listitem>
 492       </varlistentry>
 493       <varlistentry>
 494         <term><varname>AlternativeName=</varname></term>
 495         <listitem>
 496           <para>The alternative interface name to use. This option can be specified multiple times.
 497           If the empty string is assigned to this option, the list is reset, and all prior assignments
 498           have no effect. If the kernel does not support the alternative names, then this setting will
 499           be ignored.</para>
 500         </listitem>
 501       </varlistentry>
 502       <varlistentry>
 503         <term><varname>TransmitQueues=</varname></term>
 504         <listitem>
 505           <para>Specifies the device's number of transmit queues. An integer in the range 1…4096.
 506           When unset, the kernel's default will be used.</para>
 507         </listitem>
 508       </varlistentry>
 509       <varlistentry>
 510         <term><varname>ReceiveQueues=</varname></term>
 511         <listitem>
 512           <para>Specifies the device's number of receive queues. An integer in the range 1…4096.
 513           When unset, the kernel's default will be used.</para>
 514         </listitem>
 515       </varlistentry>
 516       <varlistentry>
 517         <term><varname>TransmitQueueLength=</varname></term>
 518         <listitem>
 519           <para>Specifies the transmit queue length of the device in number of packets. An unsigned integer
 520           in the range 0…4294967294. When unset, the kernel's default will be used.</para>
 521         </listitem>
 522       </varlistentry>
 523       <varlistentry>
 524         <term><varname>MTUBytes=</varname></term>
 525         <listitem>
 526           <para>The maximum transmission unit in bytes to set for the
 527           device. The usual suffixes K, M, G are supported and are
 528           understood to the base of 1024.</para>
 529         </listitem>
 530       </varlistentry>
 531       <varlistentry>
 532         <term><varname>BitsPerSecond=</varname></term>
 533         <listitem>
 534           <para>The speed to set for the device, the value is rounded
 535           down to the nearest Mbps. The usual suffixes K, M, G are
 536           supported and are understood to the base of 1000.</para>
 537         </listitem>
 538       </varlistentry>
 539       <varlistentry>
 540         <term><varname>Duplex=</varname></term>
 541         <listitem>
 542           <para>The duplex mode to set for the device. The accepted values are <option>half</option> and
 543           <option>full</option>.</para>
 544         </listitem>
 545       </varlistentry>
 546       <varlistentry>
 547         <term><varname>AutoNegotiation=</varname></term>
 548         <listitem>
 549           <para>Takes a boolean. If set to yes, automatic negotiation of transmission parameters is enabled.
 550           Autonegotiation is a procedure by which two connected ethernet devices choose
 551           common transmission parameters, such as speed, duplex mode, and flow control.
 552           When unset, the kernel's default will be used.</para>
 553
 554           <para>Note that if autonegotiation is enabled, speed and duplex settings are
 555           read-only. If autonegotiation is disabled, speed and duplex settings are writable
 556           if the driver supports multiple link modes.</para>
 557         </listitem>
 558       </varlistentry>
 559       <varlistentry>
 560         <term><varname>WakeOnLan=</varname></term>
 561         <listitem>
 562           <para>The Wake-on-LAN policy to set for the device. Takes the special value
 563           <literal>off</literal> which disables Wake-on-LAN, or space separated list of the following
 564           words:</para>
 565
 566           <variablelist>
 567             <varlistentry>
 568               <term><option>phy</option></term>
 569               <listitem>
 570                 <para>Wake on PHY activity.</para>
 571               </listitem>
 572             </varlistentry>
 573             <varlistentry>
 574               <term><option>unicast</option></term>
 575               <listitem>
 576                 <para>Wake on unicast messages.</para>
 577               </listitem>
 578             </varlistentry>
 579             <varlistentry>
 580               <term><option>multicast</option></term>
 581               <listitem>
 582                 <para>Wake on multicast messages.</para>
 583               </listitem>
 584             </varlistentry>
 585             <varlistentry>
 586               <term><option>broadcast</option></term>
 587               <listitem>
 588                 <para>Wake on broadcast messages.</para>
 589               </listitem>
 590             </varlistentry>
 591             <varlistentry>
 592               <term><option>arp</option></term>
 593               <listitem>
 594                 <para>Wake on ARP.</para>
 595               </listitem>
 596             </varlistentry>
 597             <varlistentry>
 598               <term><option>magic</option></term>
 599               <listitem>
 600                 <para>Wake on receipt of a magic packet.
 601                 </para>
 602               </listitem>
 603             </varlistentry>
 604             <varlistentry>
 605               <term><option>secureon</option></term>
 606               <listitem>
 607                 <para>Enable SecureOn password for MagicPacket. Implied when
 608                 <varname>WakeOnLanPassword=</varname> is specified. If specified without
 609                 <varname>WakeOnLanPassword=</varname> option, then the password is read from the
 610                 credential <literal><replaceable>LINK</replaceable>.link.wol.password</literal> (e.g.,
 611                 <literal>60-foo.link.wol.password</literal>), and if the credential not found, then
 612                 read from <literal>wol.password</literal>. See
 613                 <varname>LoadCredential=</varname>/<varname>SetCredential=</varname> in
 614                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 615                 for details. The password in the credential, must be 6 bytes in hex format with each
 616                 byte separated by a colon (<literal>:</literal>) like an Ethernet MAC address, e.g.,
 617                 <literal>aa:bb:cc:dd:ee:ff</literal>.</para>
 618               </listitem>
 619             </varlistentry>
 620           </variablelist>
 621
 622           <para>Defaults to unset, and the device's default will be used. This setting can be specified
 623           multiple times. If an empty string is assigned, then the all previous assignments are
 624           cleared.</para>
 625         </listitem>
 626       </varlistentry>
 627       <varlistentry>
 628         <term><varname>WakeOnLanPassword=</varname></term>
 629         <listitem>
 630           <para>Specifies the SecureOn password for MagicPacket. Takes an absolute path to a regular
 631           file or an <constant>AF_UNIX</constant> stream socket, or the plain password. When a path to
 632           a regular file is specified, the password is read from it. When an
 633           <constant>AF_UNIX</constant> stream socket is specified, a connection is made to it and the
 634           password is read from it. The password must be 6 bytes in hex format with each byte separated
 635           by a colon (<literal>:</literal>) like an Ethernet MAC address, e.g.,
 636           <literal>aa:bb:cc:dd:ee:ff</literal>. This implies <varname>WakeOnLan=secureon</varname>.
 637           Defaults to unset, and the current value will not be changed.</para>
 638         </listitem>
 639       </varlistentry>
 640       <varlistentry>
 641         <term><varname>Port=</varname></term>
 642         <listitem>
 643           <para>The port option is used to select the device port. The
 644           supported values are:</para>
 645
 646           <variablelist>
 647             <varlistentry>
 648               <term><option>tp</option></term>
 649               <listitem>
 650                 <para>An Ethernet interface using Twisted-Pair cable as the medium.</para>
 651               </listitem>
 652             </varlistentry>
 653             <varlistentry>
 654               <term><option>aui</option></term>
 655               <listitem>
 656                 <para>Attachment Unit Interface (AUI). Normally used with hubs.
 657                 </para>
 658               </listitem>
 659             </varlistentry>
 660             <varlistentry>
 661               <term><option>bnc</option></term>
 662               <listitem>
 663                 <para>An Ethernet interface using BNC connectors and co-axial cable.</para>
 664               </listitem>
 665             </varlistentry>
 666             <varlistentry>
 667               <term><option>mii</option></term>
 668               <listitem>
 669                 <para>An Ethernet interface using a Media Independent Interface (MII).</para>
 670               </listitem>
 671             </varlistentry>
 672             <varlistentry>
 673               <term><option>fibre</option></term>
 674               <listitem>
 675                 <para>An Ethernet interface using Optical Fibre as the medium.</para>
 676               </listitem>
 677             </varlistentry>
 678           </variablelist>
 679         </listitem>
 680       </varlistentry>
 681       <varlistentry>
 682         <term><varname>Advertise=</varname></term>
 683         <listitem>
 684           <para>This sets what speeds and duplex modes of operation are advertised for auto-negotiation.
 685           This implies <literal>AutoNegotiation=yes</literal>. The supported values are:
 686
 687           <table>
 688             <title>Supported advertise values</title>
 689             <tgroup cols='3'>
 690               <colspec colname='Advertise' />
 691               <colspec colname='Speed' />
 692               <colspec colname='Duplex Mode' />
 693
 694               <thead><row>
 695                 <entry>Advertise</entry>
 696                 <entry>Speed (Mbps)</entry>
 697                 <entry>Duplex Mode</entry>
 698               </row></thead>
 699               <tbody>
 700                 <row><entry><option>10baset-half</option></entry>
 701                 <entry>10</entry><entry>half</entry></row>
 702
 703                 <row><entry><option>10baset-full</option></entry>
 704                 <entry>10</entry><entry>full</entry></row>
 705
 706                 <row><entry><option>100baset-half</option></entry>
 707                 <entry>100</entry><entry>half</entry></row>
 708
 709                 <row><entry><option>100baset-full</option></entry>
 710                 <entry>100</entry><entry>full</entry></row>
 711
 712                 <row><entry><option>1000baset-half</option></entry>
 713                 <entry>1000</entry><entry>half</entry></row>
 714
 715                 <row><entry><option>1000baset-full</option></entry>
 716                 <entry>1000</entry><entry>full</entry></row>
 717
 718                 <row><entry><option>10000baset-full</option></entry>
 719                 <entry>10000</entry><entry>full</entry></row>
 720
 721                 <row><entry><option>2500basex-full</option></entry>
 722                 <entry>2500</entry><entry>full</entry></row>
 723
 724                 <row><entry><option>1000basekx-full</option></entry>
 725                 <entry>1000</entry><entry>full</entry></row>
 726
 727                 <row><entry><option>10000basekx4-full</option></entry>
 728                 <entry>10000</entry><entry>full</entry></row>
 729
 730                 <row><entry><option>10000basekr-full</option></entry>
 731                 <entry>10000</entry><entry>full</entry></row>
 732
 733                 <row><entry><option>10000baser-fec</option></entry>
 734                 <entry>10000</entry><entry>full</entry></row>
 735
 736                 <row><entry><option>20000basemld2-full</option></entry>
 737                 <entry>20000</entry><entry>full</entry></row>
 738
 739                 <row><entry><option>20000basekr2-full</option></entry>
 740                 <entry>20000</entry><entry>full</entry></row>
 741               </tbody>
 742             </tgroup>
 743           </table>
 744
 745           By default this is unset, i.e. all possible modes will be advertised.
 746           This option may be specified more than once, in which case all specified speeds and modes are advertised.
 747           If the empty string is assigned to this option, the list is reset, and all prior assignments have no effect.
 748           </para>
 749         </listitem>
 750       </varlistentry>
 751       <varlistentry>
 752         <term><varname>ReceiveChecksumOffload=</varname></term>
 753         <listitem>
 754           <para>Takes a boolean. If set to true, hardware offload for checksumming of ingress
 755           network packets is enabled. When unset, the kernel's default will be used.</para>
 756         </listitem>
 757       </varlistentry>
 758       <varlistentry>
 759         <term><varname>TransmitChecksumOffload=</varname></term>
 760         <listitem>
 761           <para>Takes a boolean. If set to true, hardware offload for checksumming of egress
 762           network packets is enabled. When unset, the kernel's default will be used.</para>
 763         </listitem>
 764       </varlistentry>
 765       <varlistentry>
 766         <term><varname>TCPSegmentationOffload=</varname></term>
 767         <listitem>
 768           <para>Takes a boolean. If set to true, TCP Segmentation Offload (TSO) is enabled.
 769           When unset, the kernel's default will be used.</para>
 770         </listitem>
 771       </varlistentry>
 772        <varlistentry>
 773       <term><varname>TCP6SegmentationOffload=</varname></term>
 774         <listitem>
 775           <para>Takes a boolean. If set to true, TCP6 Segmentation Offload (tx-tcp6-segmentation) is enabled.
 776           When unset, the kernel's default will be used.</para>
 777         </listitem>
 778       </varlistentry>
 779       <varlistentry>
 780         <term><varname>GenericSegmentationOffload=</varname></term>
 781         <listitem>
 782           <para>Takes a boolean. If set to true, Generic Segmentation Offload (GSO) is enabled.
 783           When unset, the kernel's default will be used.</para>
 784         </listitem>
 785       </varlistentry>
 786       <varlistentry>
 787         <term><varname>GenericReceiveOffload=</varname></term>
 788         <listitem>
 789           <para>Takes a boolean. If set to true, Generic Receive Offload (GRO) is enabled.
 790           When unset, the kernel's default will be used.</para>
 791         </listitem>
 792       </varlistentry>
 793       <varlistentry>
 794         <term><varname>GenericReceiveOffloadHardware=</varname></term>
 795         <listitem>
 796           <para>Takes a boolean. If set to true, hardware accelerated Generic Receive Offload (GRO) is
 797           enabled. When unset, the kernel's default will be used.</para>
 798         </listitem>
 799       </varlistentry>
 800       <varlistentry>
 801         <term><varname>LargeReceiveOffload=</varname></term>
 802         <listitem>
 803           <para>Takes a boolean. If set to true, Large Receive Offload (LRO) is enabled.
 804           When unset, the kernel's default will be used.</para>
 805         </listitem>
 806       </varlistentry>
 807       <varlistentry>
 808         <term><varname>ReceiveVLANCTAGHardwareAcceleration=</varname></term>
 809         <listitem>
 810           <para>Takes a boolean. If set to true, receive VLAN CTAG hardware acceleration is enabled.
 811           When unset, the kernel's default will be used.</para>
 812         </listitem>
 813       </varlistentry>
 814       <varlistentry>
 815         <term><varname>TransmitVLANCTAGHardwareAcceleration=</varname></term>
 816         <listitem>
 817           <para>Takes a boolean. If set to true, transmit VLAN CTAG hardware acceleration is enabled.
 818           When unset, the kernel's default will be used.</para>
 819         </listitem>
 820       </varlistentry>
 821       <varlistentry>
 822         <term><varname>ReceiveVLANCTAGFilter=</varname></term>
 823         <listitem>
 824           <para>Takes a boolean. If set to true, receive filtering on VLAN CTAGs is enabled.
 825           When unset, the kernel's default will be used.</para>
 826         </listitem>
 827       </varlistentry>
 828       <varlistentry>
 829         <term><varname>TransmitVLANSTAGHardwareAcceleration=</varname></term>
 830         <listitem>
 831           <para>Takes a boolean. If set to true, transmit VLAN STAG hardware acceleration is enabled.
 832           When unset, the kernel's default will be used.</para>
 833         </listitem>
 834       </varlistentry>
 835       <varlistentry>
 836         <term><varname>NTupleFilter=</varname></term>
 837         <listitem>
 838           <para>Takes a boolean. If set to true, receive N-tuple filters and actions are enabled.
 839           When unset, the kernel's default will be used.</para>
 840         </listitem>
 841       </varlistentry>
 842       <varlistentry>
 843         <term><varname>RxChannels=</varname></term>
 844         <term><varname>TxChannels=</varname></term>
 845         <term><varname>OtherChannels=</varname></term>
 846         <term><varname>CombinedChannels=</varname></term>
 847         <listitem>
 848           <para>Specifies the number of receive, transmit, other, or combined channels, respectively.
 849           Takes an unsigned integer in the range 1…4294967295 or <literal>max</literal>. If set to
 850           <literal>max</literal>, the advertised maximum value of the hardware will be used. When
 851           unset, the number will not be changed. Defaults to unset.</para>
 852         </listitem>
 853       </varlistentry>
 854       <varlistentry>
 855         <term><varname>RxBufferSize=</varname></term>
 856         <term><varname>RxMiniBufferSize=</varname></term>
 857         <term><varname>RxJumboBufferSize=</varname></term>
 858         <term><varname>TxBufferSize=</varname></term>
 859         <listitem>
 860           <para>Specifies the maximum number of pending packets in the NIC receive buffer, mini receive
 861           buffer, jumbo receive buffer, or transmit buffer, respectively. Takes an unsigned integer in
 862           the range 1…4294967295 or <literal>max</literal>. If set to <literal>max</literal>, the
 863           advertised maximum value of the hardware will be used. When unset, the number will not be
 864           changed. Defaults to unset.</para>
 865         </listitem>
 866       </varlistentry>
 867       <varlistentry>
 868         <term><varname>RxFlowControl=</varname></term>
 869         <listitem>
 870           <para>Takes a boolean. When set, enables receive flow control, also known as the ethernet
 871           receive PAUSE message (generate and send ethernet PAUSE frames). When unset, the kernel's
 872           default will be used.</para>
 873         </listitem>
 874       </varlistentry>
 875       <varlistentry>
 876         <term><varname>TxFlowControl=</varname></term>
 877         <listitem>
 878           <para>Takes a boolean. When set, enables transmit flow control, also known as the ethernet
 879           transmit PAUSE message (respond to received ethernet PAUSE frames). When unset, the kernel's
 880           default will be used.</para>
 881         </listitem>
 882       </varlistentry>
 883       <varlistentry>
 884         <term><varname>AutoNegotiationFlowControl=</varname></term>
 885         <listitem>
 886           <para>Takes a boolean. When set, auto negotiation enables the interface to exchange state
 887           advertisements with the connected peer so that the two devices can agree on the ethernet
 888           PAUSE configuration. When unset, the kernel's default will be used.</para>
 889         </listitem>
 890       </varlistentry>
 891       <varlistentry>
 892         <term><varname>GenericSegmentOffloadMaxBytes=</varname></term>
 893         <listitem>
 894           <para>Specifies the maximum size of a Generic Segment Offload (GSO) packet the
 895           device should accept. The usual suffixes K, M, G are supported and are
 896           understood to the base of 1024. An unsigned integer in the range 1…65536.
 897           Defaults to unset.</para>
 898         </listitem>
 899       </varlistentry>
 900       <varlistentry>
 901         <term><varname>GenericSegmentOffloadMaxSegments=</varname></term>
 902         <listitem>
 903           <para>Specifies the maximum number of Generic Segment Offload (GSO) segments the device should
 904           accept. An unsigned integer in the range 1…65535. Defaults to unset.</para>
 905         </listitem>
 906       </varlistentry>
 907       <varlistentry>
 908         <term><varname>UseAdaptiveRxCoalesce=</varname></term>
 909         <term><varname>UseAdaptiveTxCoalesce=</varname></term>
 910         <listitem>
 911           <para>Boolean properties that, when set, enable/disable adaptive Rx/Tx coalescing if the hardware
 912           supports it. When unset, the kernel's default will be used.</para>
 913         </listitem>
 914       </varlistentry>
 915       <varlistentry>
 916         <term><varname>RxCoalesceSec=</varname></term>
 917         <term><varname>RxCoalesceIrqSec=</varname></term>
 918         <term><varname>RxCoalesceLowSec=</varname></term>
 919         <term><varname>RxCoalesceHighSec=</varname></term>
 920         <term><varname>TxCoalesceSec=</varname></term>
 921         <term><varname>TxCoalesceIrqSec=</varname></term>
 922         <term><varname>TxCoalesceLowSec=</varname></term>
 923         <term><varname>TxCoalesceHighSec=</varname></term>
 924         <listitem>
 925           <para>These properties configure the delay before Rx/Tx interrupts are generated after a packet is
 926           sent/received. The <literal>Irq</literal> properties come into effect when the host is servicing an
 927           IRQ. The <literal>Low</literal> and <literal>High</literal> properties come into effect when the
 928           packet rate drops below the low packet rate threshold or exceeds the high packet rate threshold
 929           respectively if adaptive Rx/Tx coalescing is enabled. When unset, the kernel's defaults will be
 930           used.</para>
 931         </listitem>
 932       </varlistentry>
 933         <varlistentry>
 934         <term><varname>RxMaxCoalescedFrames=</varname></term>
 935         <term><varname>RxMaxCoalescedIrqFrames=</varname></term>
 936         <term><varname>RxMaxCoalescedLowFrames=</varname></term>
 937         <term><varname>RxMaxCoalescedHighFrames=</varname></term>
 938         <term><varname>TxMaxCoalescedFrames=</varname></term>
 939         <term><varname>TxMaxCoalescedIrqFrames=</varname></term>
 940         <term><varname>TxMaxCoalescedLowFrames=</varname></term>
 941         <term><varname>TxMaxCoalescedHighFrames=</varname></term>
 942         <listitem>
 943           <para>These properties configure the maximum number of frames that are sent/received before a Rx/Tx
 944           interrupt is generated. The <literal>Irq</literal> properties come into effect when the host is
 945           servicing an IRQ. The <literal>Low</literal> and <literal>High</literal> properties come into
 946           effect when the packet rate drops below the low packet rate threshold or exceeds the high packet
 947           rate threshold respectively if adaptive Rx/Tx coalescing is enabled. When unset, the kernel's
 948           defaults will be used.</para>
 949         </listitem>
 950       </varlistentry>
 951       <varlistentry>
 952         <term><varname>CoalescePacketRateLow=</varname></term>
 953         <term><varname>CoalescePacketRateHigh=</varname></term>
 954         <listitem>
 955           <para>These properties configure the low and high packet rate (expressed in packets per second)
 956           threshold respectively and are used to determine when the corresponding coalescing settings for low
 957           and high packet rates come into effect if adaptive Rx/Tx coalescing is enabled. If unset, the
 958           kernel's defaults will be used.</para>
 959         </listitem>
 960       </varlistentry>
 961       <varlistentry>
 962         <term><varname>CoalescePacketRateSampleIntervalSec=</varname></term>
 963         <listitem>
 964           <para>Configures how often to sample the packet rate used for adaptive Rx/Tx coalescing. This
 965           property cannot be zero. This lowest time granularity supported by this property is seconds.
 966           Partial seconds will be rounded up before being passed to the kernel. If unset, the kernel's
 967           default will be used.</para>
 968         </listitem>
 969       </varlistentry>
 970       <varlistentry>
 971         <term><varname>StatisticsBlockCoalesceSec=</varname></term>
 972         <listitem>
 973           <para>How long to delay driver in-memory statistics block updates. If the driver does not have an
 974           in-memory statistic block, this property is ignored. This property cannot be zero. If unset, the
 975           kernel's default will be used.</para>
 976         </listitem>
 977       </varlistentry>
 978
 979       <varlistentry>
 980         <term><varname>MDI=</varname></term>
 981         <listitem>
 982           <para>Specifies the medium dependent interface (MDI) mode for the interface. A MDI describes
 983           the interface from a physical layer implementation to the physical medium used to carry the
 984           transmission. Takes one of the following words: <literal>straight</literal> (or equivalently:
 985           <literal>mdi</literal>), <literal>crossover</literal> (or equivalently:
 986           <literal>mdi-x</literal>, <literal>mdix</literal>), and <literal>auto</literal>. When
 987           <literal>straight</literal>, the MDI straight through mode will be used. When
 988           <literal>crossover</literal>, the MDI crossover (MDI-X) mode will be used. When
 989           <literal>auto</literal>, the MDI status is automatically detected. Defaults to unset, and the
 990           kernel's default will be used.</para>
 991         </listitem>
 992       </varlistentry>
 993
 994       <varlistentry>
 995         <term><varname>SR-IOVVirtualFunctions=</varname></term>
 996         <listitem>
 997           <para>Specifies the number of SR-IOV virtual functions. Takes an integer in the range
 998           0…2147483647. Defaults to unset, and automatically determined from the values specified in
 999           the <varname>VirtualFunction=</varname> settings in the [SR-IOV] sections.</para>
1000         </listitem>
1001       </varlistentry>
1002
1003     </variablelist>
1004   </refsect1>
1005
1006   <refsect1 id='sr-iov'>
1007     <title>[SR-IOV] Section Options</title>
1008     <para>The [SR-IOV] section accepts the following keys. Specify several [SR-IOV] sections to
1009     configure several SR-IOVs. SR-IOV provides the ability to partition a single physical PCI resource
1010     into virtual PCI functions which can then be injected into a VM. In the case of network VFs, SR-IOV
1011     improves north-south network performance (that is, traffic with endpoints outside the host machine)
1012     by allowing traffic to bypass the host machine’s network stack.</para>
1013
1014     <variablelist class='network-directives'>
1015       <varlistentry>
1016         <term><varname>VirtualFunction=</varname></term>
1017         <listitem>
1018           <para>Specifies a Virtual Function (VF), lightweight PCIe function designed solely to move
1019           data in and out. Takes an integer in the range 0…2147483646. This option is compulsory.
1020           </para>
1021         </listitem>
1022       </varlistentry>
1023
1024       <varlistentry>
1025         <term><varname>VLANId=</varname></term>
1026         <listitem>
1027           <para>Specifies VLAN ID of the virtual function. Takes an integer in the range 1…4095.</para>
1028         </listitem>
1029       </varlistentry>
1030
1031       <varlistentry>
1032         <term><varname>QualityOfService=</varname></term>
1033         <listitem>
1034           <para>Specifies quality of service of the virtual function. Takes an integer in the range
1035           1…4294967294.</para>
1036         </listitem>
1037       </varlistentry>
1038
1039       <varlistentry>
1040         <term><varname>VLANProtocol=</varname></term>
1041         <listitem>
1042           <para>Specifies VLAN protocol of the virtual function. Takes <literal>802.1Q</literal> or
1043           <literal>802.1ad</literal>.</para>
1044         </listitem>
1045       </varlistentry>
1046
1047       <varlistentry>
1048         <term><varname>MACSpoofCheck=</varname></term>
1049         <listitem>
1050           <para>Takes a boolean. Controls the MAC spoof checking. When unset, the kernel's default will
1051           be used.</para>
1052         </listitem>
1053       </varlistentry>
1054
1055       <varlistentry>
1056         <term><varname>QueryReceiveSideScaling=</varname></term>
1057         <listitem>
1058           <para>Takes a boolean. Toggle the ability of querying the receive side scaling (RSS)
1059           configuration of the virtual function (VF). The VF RSS information like RSS hash key may be
1060           considered sensitive on some devices where this information is shared between VF and the
1061           physical function (PF). When unset, the kernel's default will be used.</para>
1062         </listitem>
1063       </varlistentry>
1064
1065       <varlistentry>
1066         <term><varname>Trust=</varname></term>
1067         <listitem>
1068           <para>Takes a boolean. Allows one to set trust mode of the virtual function (VF). When set,
1069           VF users can set a specific feature which may impact security and/or performance. When unset,
1070           the kernel's default will be used.</para>
1071         </listitem>
1072       </varlistentry>
1073
1074       <varlistentry>
1075         <term><varname>LinkState=</varname></term>
1076         <listitem>
1077           <para>Allows one to set the link state of the virtual function (VF). Takes a boolean or a
1078           special value <literal>auto</literal>. Setting to <literal>auto</literal> means a
1079           reflection of the physical function (PF) link state, <literal>yes</literal> lets the VF to
1080           communicate with other VFs on this host even if the PF link state is down,
1081           <literal>no</literal> causes the hardware to drop any packets sent by the VF. When unset,
1082           the kernel's default will be used.</para>
1083         </listitem>
1084       </varlistentry>
1085
1086       <varlistentry>
1087         <term><varname>MACAddress=</varname></term>
1088         <listitem>
1089           <para>Specifies the MAC address for the virtual function.</para>
1090         </listitem>
1091       </varlistentry>
1092     </variablelist>
1093   </refsect1>
1094
1095   <refsect1>
1096     <title>Examples</title>
1097
1098     <example>
1099       <title>/usr/lib/systemd/network/99-default.link</title>
1100
1101       <para>The link file <filename>99-default.link</filename> that is
1102       shipped with systemd defines the default naming policy for
1103       links.</para>
1104
1105       <programlisting>[Link]
1106 NamePolicy=kernel database onboard slot path
1107 MACAddressPolicy=persistent</programlisting>
1108     </example>
1109
1110     <example>
1111       <title>/etc/systemd/network/10-dmz.link</title>
1112
1113       <para>This example assigns the fixed name <literal>dmz0</literal> to the interface with the MAC address
1114       00:a0:de:63:7a:e6:</para>
1115
1116       <programlisting>[Match]
1117 MACAddress=00:a0:de:63:7a:e6
1118
1119 [Link]
1120 Name=dmz0</programlisting>
1121
1122       <para><varname>NamePolicy=</varname> is not set, so <varname>Name=</varname> takes effect. We use the
1123       <literal>10-</literal> prefix to order this file early in the list. Note that it needs to be before
1124       <literal>99-link</literal>, i.e. it needs a numerical prefix, to have any effect at all.</para>
1125     </example>
1126
1127     <example>
1128       <title>Debugging <varname>NamePolicy=</varname> assignments</title>
1129
1130       <programlisting>$ sudo SYSTEMD_LOG_LEVEL=debug udevadm test-builtin net_setup_link /sys/class/net/hub0
1131 …
1132 Parsed configuration file /usr/lib/systemd/network/99-default.link
1133 Parsed configuration file /etc/systemd/network/10-eth0.link
1134 ID_NET_DRIVER=cdc_ether
1135 Config file /etc/systemd/network/10-eth0.link applies to device hub0
1136 link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
1137 hub0: Device has name_assign_type=4
1138 Using default interface naming scheme 'v240'.
1139 hub0: Policies didn't yield a name, using specified Name=hub0.
1140 ID_NET_LINK_FILE=/etc/systemd/network/10-eth0.link
1141 ID_NET_NAME=hub0
1142 …</programlisting>
1143
1144      <para>Explicit <varname>Name=</varname> configuration wins in this case.</para>
1145
1146      <programlisting>sudo SYSTEMD_LOG_LEVEL=debug udevadm test-builtin net_setup_link /sys/class/net/enp0s31f6
1147 …
1148 Parsed configuration file /usr/lib/systemd/network/99-default.link
1149 Parsed configuration file /etc/systemd/network/10-eth0.link
1150 Created link configuration context.
1151 ID_NET_DRIVER=e1000e
1152 Config file /usr/lib/systemd/network/99-default.link applies to device enp0s31f6
1153 link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
1154 enp0s31f6: Device has name_assign_type=4
1155 Using default interface naming scheme 'v240'.
1156 enp0s31f6: Policy *keep*: keeping existing userspace name
1157 enp0s31f6: Device has addr_assign_type=0
1158 enp0s31f6: MAC on the device already matches policy *persistent*
1159 ID_NET_LINK_FILE=/usr/lib/systemd/network/99-default.link
1160 …
1161 </programlisting>
1162
1163      <para>In this case, the interface was already renamed, so the <option>keep</option> policy specified as
1164      the first option in <filename index="false">99-default.link</filename> means that the existing name is
1165      preserved. If <option>keep</option> was removed, or if were in boot before the renaming has happened,
1166      we might get the following instead:</para>
1167
1168      <programlisting>enp0s31f6: Policy *path* yields "enp0s31f6".
1169 enp0s31f6: Device has addr_assign_type=0
1170 enp0s31f6: MAC on the device already matches policy *persistent*
1171 ID_NET_LINK_FILE=/usr/lib/systemd/network/99-default.link
1172 ID_NET_NAME=enp0s31f6
1173 …
1174 </programlisting>
1175
1176       <para>Please note that the details of output are subject to change.</para>
1177     </example>
1178
1179     <example>
1180       <title>/etc/systemd/network/10-internet.link</title>
1181
1182       <para>This example assigns the fixed name
1183       <literal>internet0</literal> to the interface with the device
1184       path <literal>pci-0000:00:1a.0-*</literal>:</para>
1185
1186       <programlisting>[Match]
1187 Path=pci-0000:00:1a.0-*
1188
1189 [Link]
1190 Name=internet0</programlisting>
1191     </example>
1192
1193     <example>
1194       <title>/etc/systemd/network/25-wireless.link</title>
1195
1196       <para>Here's an overly complex example that shows the use of a large number of [Match] and [Link] settings.</para>
1197
1198       <programlisting>[Match]
1199 MACAddress=12:34:56:78:9a:bc
1200 Driver=brcmsmac
1201 Path=pci-0000:02:00.0-*
1202 Type=wlan
1203 Virtualization=no
1204 Host=my-laptop
1205 Architecture=x86-64
1206
1207 [Link]
1208 Name=wireless0
1209 MTUBytes=1450
1210 BitsPerSecond=10M
1211 WakeOnLan=magic
1212 MACAddress=cb:a9:87:65:43:21</programlisting>
1213     </example>
1214   </refsect1>
1215
1216   <refsect1>
1217     <title>See Also</title>
1218     <para>
1219       <citerefentry>
1220         <refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum>
1221       </citerefentry>,
1222       <citerefentry>
1223         <refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
1224       </citerefentry>,
1225       <citerefentry>
1226         <refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum>
1227       </citerefentry>,
1228       <citerefentry>
1229         <refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum>
1230       </citerefentry>,
1231       <citerefentry>
1232         <refentrytitle>systemd-network-generator.service</refentrytitle><manvolnum>8</manvolnum>
1233       </citerefentry>
1234     </para>
1235   </refsect1>
1236
1237 </refentry>