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-udevd.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 interface (for example
 472           <literal>eth0</literal>) is dangerous because the name assignment done by udev will race with the
 473           assignment done by the kernel, and only one interface may use the name. Depending on the order of
 474           operations, either udev or the kernel will win, making the naming unpredictable. It is best to use
 475           some different prefix, for example <literal>internal0</literal>/<literal>external0</literal> or
 476           <literal>lan0</literal>/<literal>lan1</literal>/<literal>lan3</literal>.</para>
 477
 478           <para>Interface names must have a minimum length of 1 character and a maximum length of 15
 479           characters, and may contain any 7bit ASCII character, with the exception of control characters,
 480           <literal>:</literal>, <literal>/</literal> and <literal>%</literal>. While <literal>.</literal> is
 481           an allowed character, it's recommended to avoid it when naming interfaces as various tools (such as
 482           <citerefentry><refentrytitle>resolvconf</refentrytitle><manvolnum>1</manvolnum></citerefentry>) use
 483           it as separator character. Also, fully numeric interface names are not allowed (in order to avoid
 484           ambiguity with interface specification by numeric indexes), as are the special strings
 485           <literal>.</literal>, <literal>..</literal>, <literal>all</literal> and
 486           <literal>default</literal>.</para>
 487         </listitem>
 488       </varlistentry>
 489       <varlistentry>
 490         <term><varname>AlternativeNamesPolicy=</varname></term>
 491         <listitem>
 492           <para>A space-separated list of policies by which the interface's alternative names
 493           should be set. Each of the policies may fail, and all successful policies are used. The
 494           available policies are <literal>database</literal>, <literal>onboard</literal>,
 495           <literal>slot</literal>, <literal>path</literal>, and <literal>mac</literal>. If the
 496           kernel does not support the alternative names, then this setting will be ignored.
 497           </para>
 498         </listitem>
 499       </varlistentry>
 500       <varlistentry>
 501         <term><varname>AlternativeName=</varname></term>
 502         <listitem>
 503           <para>The alternative interface name to use. This option can be specified multiple times.
 504           If the empty string is assigned to this option, the list is reset, and all prior assignments
 505           have no effect. If the kernel does not support the alternative names, then this setting will
 506           be ignored.</para>
 507
 508           <para>Alternative interface names may be used to identify interfaces in various tools. In contrast
 509           to the primary name (as configured with <varname>Name=</varname> above) there may be multiple
 510           alternative names referring to the same interface. Alternative names may have a maximum length of
 511           127 characters, in contrast to the 15 allowed for the primary interface name, but otherwise are
 512           subject to the same naming constraints.</para>
 513         </listitem>
 514       </varlistentry>
 515       <varlistentry>
 516         <term><varname>TransmitQueues=</varname></term>
 517         <listitem>
 518           <para>Specifies the device's number of transmit queues. An integer in the range 1…4096.
 519           When unset, the kernel's default will be used.</para>
 520         </listitem>
 521       </varlistentry>
 522       <varlistentry>
 523         <term><varname>ReceiveQueues=</varname></term>
 524         <listitem>
 525           <para>Specifies the device's number of receive queues. An integer in the range 1…4096.
 526           When unset, the kernel's default will be used.</para>
 527         </listitem>
 528       </varlistentry>
 529       <varlistentry>
 530         <term><varname>TransmitQueueLength=</varname></term>
 531         <listitem>
 532           <para>Specifies the transmit queue length of the device in number of packets. An unsigned integer
 533           in the range 0…4294967294. When unset, the kernel's default will be used.</para>
 534         </listitem>
 535       </varlistentry>
 536       <varlistentry>
 537         <term><varname>MTUBytes=</varname></term>
 538         <listitem>
 539           <para>The maximum transmission unit in bytes to set for the
 540           device. The usual suffixes K, M, G are supported and are
 541           understood to the base of 1024.</para>
 542         </listitem>
 543       </varlistentry>
 544       <varlistentry>
 545         <term><varname>BitsPerSecond=</varname></term>
 546         <listitem>
 547           <para>The speed to set for the device, the value is rounded
 548           down to the nearest Mbps. The usual suffixes K, M, G are
 549           supported and are understood to the base of 1000.</para>
 550         </listitem>
 551       </varlistentry>
 552       <varlistentry>
 553         <term><varname>Duplex=</varname></term>
 554         <listitem>
 555           <para>The duplex mode to set for the device. The accepted values are <option>half</option> and
 556           <option>full</option>.</para>
 557         </listitem>
 558       </varlistentry>
 559       <varlistentry>
 560         <term><varname>AutoNegotiation=</varname></term>
 561         <listitem>
 562           <para>Takes a boolean. If set to yes, automatic negotiation of transmission parameters is enabled.
 563           Autonegotiation is a procedure by which two connected ethernet devices choose
 564           common transmission parameters, such as speed, duplex mode, and flow control.
 565           When unset, the kernel's default will be used.</para>
 566
 567           <para>Note that if autonegotiation is enabled, speed and duplex settings are
 568           read-only. If autonegotiation is disabled, speed and duplex settings are writable
 569           if the driver supports multiple link modes.</para>
 570         </listitem>
 571       </varlistentry>
 572       <varlistentry>
 573         <term><varname>WakeOnLan=</varname></term>
 574         <listitem>
 575           <para>The Wake-on-LAN policy to set for the device. Takes the special value
 576           <literal>off</literal> which disables Wake-on-LAN, or space separated list of the following
 577           words:</para>
 578
 579           <variablelist>
 580             <varlistentry>
 581               <term><option>phy</option></term>
 582               <listitem>
 583                 <para>Wake on PHY activity.</para>
 584               </listitem>
 585             </varlistentry>
 586             <varlistentry>
 587               <term><option>unicast</option></term>
 588               <listitem>
 589                 <para>Wake on unicast messages.</para>
 590               </listitem>
 591             </varlistentry>
 592             <varlistentry>
 593               <term><option>multicast</option></term>
 594               <listitem>
 595                 <para>Wake on multicast messages.</para>
 596               </listitem>
 597             </varlistentry>
 598             <varlistentry>
 599               <term><option>broadcast</option></term>
 600               <listitem>
 601                 <para>Wake on broadcast messages.</para>
 602               </listitem>
 603             </varlistentry>
 604             <varlistentry>
 605               <term><option>arp</option></term>
 606               <listitem>
 607                 <para>Wake on ARP.</para>
 608               </listitem>
 609             </varlistentry>
 610             <varlistentry>
 611               <term><option>magic</option></term>
 612               <listitem>
 613                 <para>Wake on receipt of a magic packet.
 614                 </para>
 615               </listitem>
 616             </varlistentry>
 617             <varlistentry>
 618               <term><option>secureon</option></term>
 619               <listitem>
 620                 <para>Enable SecureOn password for MagicPacket. Implied when
 621                 <varname>WakeOnLanPassword=</varname> is specified. If specified without
 622                 <varname>WakeOnLanPassword=</varname> option, then the password is read from the
 623                 credential <literal><replaceable>LINK</replaceable>.link.wol.password</literal> (e.g.,
 624                 <literal>60-foo.link.wol.password</literal>), and if the credential not found, then
 625                 read from <literal>wol.password</literal>. See
 626                 <varname>LoadCredential=</varname>/<varname>SetCredential=</varname> in
 627                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 628                 for details. The password in the credential, must be 6 bytes in hex format with each
 629                 byte separated by a colon (<literal>:</literal>) like an Ethernet MAC address, e.g.,
 630                 <literal>aa:bb:cc:dd:ee:ff</literal>.</para>
 631               </listitem>
 632             </varlistentry>
 633           </variablelist>
 634
 635           <para>Defaults to unset, and the device's default will be used. This setting can be specified
 636           multiple times. If an empty string is assigned, then the all previous assignments are
 637           cleared.</para>
 638         </listitem>
 639       </varlistentry>
 640       <varlistentry>
 641         <term><varname>WakeOnLanPassword=</varname></term>
 642         <listitem>
 643           <para>Specifies the SecureOn password for MagicPacket. Takes an absolute path to a regular
 644           file or an <constant>AF_UNIX</constant> stream socket, or the plain password. When a path to
 645           a regular file is specified, the password is read from it. When an
 646           <constant>AF_UNIX</constant> stream socket is specified, a connection is made to it and the
 647           password is read from it. The password must be 6 bytes in hex format with each byte separated
 648           by a colon (<literal>:</literal>) like an Ethernet MAC address, e.g.,
 649           <literal>aa:bb:cc:dd:ee:ff</literal>. This implies <varname>WakeOnLan=secureon</varname>.
 650           Defaults to unset, and the current value will not be changed.</para>
 651         </listitem>
 652       </varlistentry>
 653       <varlistentry>
 654         <term><varname>Port=</varname></term>
 655         <listitem>
 656           <para>The port option is used to select the device port. The
 657           supported values are:</para>
 658
 659           <variablelist>
 660             <varlistentry>
 661               <term><option>tp</option></term>
 662               <listitem>
 663                 <para>An Ethernet interface using Twisted-Pair cable as the medium.</para>
 664               </listitem>
 665             </varlistentry>
 666             <varlistentry>
 667               <term><option>aui</option></term>
 668               <listitem>
 669                 <para>Attachment Unit Interface (AUI). Normally used with hubs.
 670                 </para>
 671               </listitem>
 672             </varlistentry>
 673             <varlistentry>
 674               <term><option>bnc</option></term>
 675               <listitem>
 676                 <para>An Ethernet interface using BNC connectors and co-axial cable.</para>
 677               </listitem>
 678             </varlistentry>
 679             <varlistentry>
 680               <term><option>mii</option></term>
 681               <listitem>
 682                 <para>An Ethernet interface using a Media Independent Interface (MII).</para>
 683               </listitem>
 684             </varlistentry>
 685             <varlistentry>
 686               <term><option>fibre</option></term>
 687               <listitem>
 688                 <para>An Ethernet interface using Optical Fibre as the medium.</para>
 689               </listitem>
 690             </varlistentry>
 691           </variablelist>
 692         </listitem>
 693       </varlistentry>
 694       <varlistentry>
 695         <term><varname>Advertise=</varname></term>
 696         <listitem>
 697           <para>This sets what speeds and duplex modes of operation are advertised for auto-negotiation.
 698           This implies <literal>AutoNegotiation=yes</literal>. The supported values are:
 699
 700           <table>
 701             <title>Supported advertise values</title>
 702             <tgroup cols='3'>
 703               <colspec colname='Advertise' />
 704               <colspec colname='Speed' />
 705               <colspec colname='Duplex Mode' />
 706
 707               <thead><row>
 708                 <entry>Advertise</entry>
 709                 <entry>Speed (Mbps)</entry>
 710                 <entry>Duplex Mode</entry>
 711               </row></thead>
 712               <tbody>
 713                 <row><entry><option>10baset-half</option></entry>
 714                 <entry>10</entry><entry>half</entry></row>
 715
 716                 <row><entry><option>10baset-full</option></entry>
 717                 <entry>10</entry><entry>full</entry></row>
 718
 719                 <row><entry><option>100baset-half</option></entry>
 720                 <entry>100</entry><entry>half</entry></row>
 721
 722                 <row><entry><option>100baset-full</option></entry>
 723                 <entry>100</entry><entry>full</entry></row>
 724
 725                 <row><entry><option>1000baset-half</option></entry>
 726                 <entry>1000</entry><entry>half</entry></row>
 727
 728                 <row><entry><option>1000baset-full</option></entry>
 729                 <entry>1000</entry><entry>full</entry></row>
 730
 731                 <row><entry><option>10000baset-full</option></entry>
 732                 <entry>10000</entry><entry>full</entry></row>
 733
 734                 <row><entry><option>2500basex-full</option></entry>
 735                 <entry>2500</entry><entry>full</entry></row>
 736
 737                 <row><entry><option>1000basekx-full</option></entry>
 738                 <entry>1000</entry><entry>full</entry></row>
 739
 740                 <row><entry><option>10000basekx4-full</option></entry>
 741                 <entry>10000</entry><entry>full</entry></row>
 742
 743                 <row><entry><option>10000basekr-full</option></entry>
 744                 <entry>10000</entry><entry>full</entry></row>
 745
 746                 <row><entry><option>10000baser-fec</option></entry>
 747                 <entry>10000</entry><entry>full</entry></row>
 748
 749                 <row><entry><option>20000basemld2-full</option></entry>
 750                 <entry>20000</entry><entry>full</entry></row>
 751
 752                 <row><entry><option>20000basekr2-full</option></entry>
 753                 <entry>20000</entry><entry>full</entry></row>
 754               </tbody>
 755             </tgroup>
 756           </table>
 757
 758           By default this is unset, i.e. all possible modes will be advertised.
 759           This option may be specified more than once, in which case all specified speeds and modes are advertised.
 760           If the empty string is assigned to this option, the list is reset, and all prior assignments have no effect.
 761           </para>
 762         </listitem>
 763       </varlistentry>
 764       <varlistentry>
 765         <term><varname>ReceiveChecksumOffload=</varname></term>
 766         <listitem>
 767           <para>Takes a boolean. If set to true, hardware offload for checksumming of ingress
 768           network packets is enabled. When unset, the kernel's default will be used.</para>
 769         </listitem>
 770       </varlistentry>
 771       <varlistentry>
 772         <term><varname>TransmitChecksumOffload=</varname></term>
 773         <listitem>
 774           <para>Takes a boolean. If set to true, hardware offload for checksumming of egress
 775           network packets is enabled. When unset, the kernel's default will be used.</para>
 776         </listitem>
 777       </varlistentry>
 778       <varlistentry>
 779         <term><varname>TCPSegmentationOffload=</varname></term>
 780         <listitem>
 781           <para>Takes a boolean. If set to true, TCP Segmentation Offload (TSO) is enabled.
 782           When unset, the kernel's default will be used.</para>
 783         </listitem>
 784       </varlistentry>
 785        <varlistentry>
 786       <term><varname>TCP6SegmentationOffload=</varname></term>
 787         <listitem>
 788           <para>Takes a boolean. If set to true, TCP6 Segmentation Offload (tx-tcp6-segmentation) is enabled.
 789           When unset, the kernel's default will be used.</para>
 790         </listitem>
 791       </varlistentry>
 792       <varlistentry>
 793         <term><varname>GenericSegmentationOffload=</varname></term>
 794         <listitem>
 795           <para>Takes a boolean. If set to true, Generic Segmentation Offload (GSO) is enabled.
 796           When unset, the kernel's default will be used.</para>
 797         </listitem>
 798       </varlistentry>
 799       <varlistentry>
 800         <term><varname>GenericReceiveOffload=</varname></term>
 801         <listitem>
 802           <para>Takes a boolean. If set to true, Generic Receive Offload (GRO) is enabled.
 803           When unset, the kernel's default will be used.</para>
 804         </listitem>
 805       </varlistentry>
 806       <varlistentry>
 807         <term><varname>GenericReceiveOffloadHardware=</varname></term>
 808         <listitem>
 809           <para>Takes a boolean. If set to true, hardware accelerated Generic Receive Offload (GRO) is
 810           enabled. When unset, the kernel's default will be used.</para>
 811         </listitem>
 812       </varlistentry>
 813       <varlistentry>
 814         <term><varname>LargeReceiveOffload=</varname></term>
 815         <listitem>
 816           <para>Takes a boolean. If set to true, Large Receive Offload (LRO) is enabled.
 817           When unset, the kernel's default will be used.</para>
 818         </listitem>
 819       </varlistentry>
 820       <varlistentry>
 821         <term><varname>ReceiveVLANCTAGHardwareAcceleration=</varname></term>
 822         <listitem>
 823           <para>Takes a boolean. If set to true, receive VLAN CTAG hardware acceleration is enabled.
 824           When unset, the kernel's default will be used.</para>
 825         </listitem>
 826       </varlistentry>
 827       <varlistentry>
 828         <term><varname>TransmitVLANCTAGHardwareAcceleration=</varname></term>
 829         <listitem>
 830           <para>Takes a boolean. If set to true, transmit VLAN CTAG hardware acceleration is enabled.
 831           When unset, the kernel's default will be used.</para>
 832         </listitem>
 833       </varlistentry>
 834       <varlistentry>
 835         <term><varname>ReceiveVLANCTAGFilter=</varname></term>
 836         <listitem>
 837           <para>Takes a boolean. If set to true, receive filtering on VLAN CTAGs is enabled.
 838           When unset, the kernel's default will be used.</para>
 839         </listitem>
 840       </varlistentry>
 841       <varlistentry>
 842         <term><varname>TransmitVLANSTAGHardwareAcceleration=</varname></term>
 843         <listitem>
 844           <para>Takes a boolean. If set to true, transmit VLAN STAG hardware acceleration is enabled.
 845           When unset, the kernel's default will be used.</para>
 846         </listitem>
 847       </varlistentry>
 848       <varlistentry>
 849         <term><varname>NTupleFilter=</varname></term>
 850         <listitem>
 851           <para>Takes a boolean. If set to true, receive N-tuple filters and actions are enabled.
 852           When unset, the kernel's default will be used.</para>
 853         </listitem>
 854       </varlistentry>
 855       <varlistentry>
 856         <term><varname>RxChannels=</varname></term>
 857         <term><varname>TxChannels=</varname></term>
 858         <term><varname>OtherChannels=</varname></term>
 859         <term><varname>CombinedChannels=</varname></term>
 860         <listitem>
 861           <para>Specifies the number of receive, transmit, other, or combined channels, respectively.
 862           Takes an unsigned integer in the range 1…4294967295 or <literal>max</literal>. If set to
 863           <literal>max</literal>, the advertised maximum value of the hardware will be used. When
 864           unset, the number will not be changed. Defaults to unset.</para>
 865         </listitem>
 866       </varlistentry>
 867       <varlistentry>
 868         <term><varname>RxBufferSize=</varname></term>
 869         <term><varname>RxMiniBufferSize=</varname></term>
 870         <term><varname>RxJumboBufferSize=</varname></term>
 871         <term><varname>TxBufferSize=</varname></term>
 872         <listitem>
 873           <para>Specifies the maximum number of pending packets in the NIC receive buffer, mini receive
 874           buffer, jumbo receive buffer, or transmit buffer, respectively. Takes an unsigned integer in
 875           the range 1…4294967295 or <literal>max</literal>. If set to <literal>max</literal>, the
 876           advertised maximum value of the hardware will be used. When unset, the number will not be
 877           changed. Defaults to unset.</para>
 878         </listitem>
 879       </varlistentry>
 880       <varlistentry>
 881         <term><varname>RxFlowControl=</varname></term>
 882         <listitem>
 883           <para>Takes a boolean. When set, enables receive flow control, also known as the ethernet
 884           receive PAUSE message (generate and send ethernet PAUSE frames). When unset, the kernel's
 885           default will be used.</para>
 886         </listitem>
 887       </varlistentry>
 888       <varlistentry>
 889         <term><varname>TxFlowControl=</varname></term>
 890         <listitem>
 891           <para>Takes a boolean. When set, enables transmit flow control, also known as the ethernet
 892           transmit PAUSE message (respond to received ethernet PAUSE frames). When unset, the kernel's
 893           default will be used.</para>
 894         </listitem>
 895       </varlistentry>
 896       <varlistentry>
 897         <term><varname>AutoNegotiationFlowControl=</varname></term>
 898         <listitem>
 899           <para>Takes a boolean. When set, auto negotiation enables the interface to exchange state
 900           advertisements with the connected peer so that the two devices can agree on the ethernet
 901           PAUSE configuration. When unset, the kernel's default will be used.</para>
 902         </listitem>
 903       </varlistentry>
 904       <varlistentry>
 905         <term><varname>GenericSegmentOffloadMaxBytes=</varname></term>
 906         <listitem>
 907           <para>Specifies the maximum size of a Generic Segment Offload (GSO) packet the
 908           device should accept. The usual suffixes K, M, G are supported and are
 909           understood to the base of 1024. An unsigned integer in the range 1…65536.
 910           Defaults to unset.</para>
 911         </listitem>
 912       </varlistentry>
 913       <varlistentry>
 914         <term><varname>GenericSegmentOffloadMaxSegments=</varname></term>
 915         <listitem>
 916           <para>Specifies the maximum number of Generic Segment Offload (GSO) segments the device should
 917           accept. An unsigned integer in the range 1…65535. Defaults to unset.</para>
 918         </listitem>
 919       </varlistentry>
 920       <varlistentry>
 921         <term><varname>UseAdaptiveRxCoalesce=</varname></term>
 922         <term><varname>UseAdaptiveTxCoalesce=</varname></term>
 923         <listitem>
 924           <para>Boolean properties that, when set, enable/disable adaptive Rx/Tx coalescing if the hardware
 925           supports it. When unset, the kernel's default will be used.</para>
 926         </listitem>
 927       </varlistentry>
 928       <varlistentry>
 929         <term><varname>RxCoalesceSec=</varname></term>
 930         <term><varname>RxCoalesceIrqSec=</varname></term>
 931         <term><varname>RxCoalesceLowSec=</varname></term>
 932         <term><varname>RxCoalesceHighSec=</varname></term>
 933         <term><varname>TxCoalesceSec=</varname></term>
 934         <term><varname>TxCoalesceIrqSec=</varname></term>
 935         <term><varname>TxCoalesceLowSec=</varname></term>
 936         <term><varname>TxCoalesceHighSec=</varname></term>
 937         <listitem>
 938           <para>These properties configure the delay before Rx/Tx interrupts are generated after a packet is
 939           sent/received. The <literal>Irq</literal> properties come into effect when the host is servicing an
 940           IRQ. The <literal>Low</literal> and <literal>High</literal> properties come into effect when the
 941           packet rate drops below the low packet rate threshold or exceeds the high packet rate threshold
 942           respectively if adaptive Rx/Tx coalescing is enabled. When unset, the kernel's defaults will be
 943           used.</para>
 944         </listitem>
 945       </varlistentry>
 946         <varlistentry>
 947         <term><varname>RxMaxCoalescedFrames=</varname></term>
 948         <term><varname>RxMaxCoalescedIrqFrames=</varname></term>
 949         <term><varname>RxMaxCoalescedLowFrames=</varname></term>
 950         <term><varname>RxMaxCoalescedHighFrames=</varname></term>
 951         <term><varname>TxMaxCoalescedFrames=</varname></term>
 952         <term><varname>TxMaxCoalescedIrqFrames=</varname></term>
 953         <term><varname>TxMaxCoalescedLowFrames=</varname></term>
 954         <term><varname>TxMaxCoalescedHighFrames=</varname></term>
 955         <listitem>
 956           <para>These properties configure the maximum number of frames that are sent/received before a Rx/Tx
 957           interrupt is generated. The <literal>Irq</literal> properties come into effect when the host is
 958           servicing an IRQ. The <literal>Low</literal> and <literal>High</literal> properties come into
 959           effect when the packet rate drops below the low packet rate threshold or exceeds the high packet
 960           rate threshold respectively if adaptive Rx/Tx coalescing is enabled. When unset, the kernel's
 961           defaults will be used.</para>
 962         </listitem>
 963       </varlistentry>
 964       <varlistentry>
 965         <term><varname>CoalescePacketRateLow=</varname></term>
 966         <term><varname>CoalescePacketRateHigh=</varname></term>
 967         <listitem>
 968           <para>These properties configure the low and high packet rate (expressed in packets per second)
 969           threshold respectively and are used to determine when the corresponding coalescing settings for low
 970           and high packet rates come into effect if adaptive Rx/Tx coalescing is enabled. If unset, the
 971           kernel's defaults will be used.</para>
 972         </listitem>
 973       </varlistentry>
 974       <varlistentry>
 975         <term><varname>CoalescePacketRateSampleIntervalSec=</varname></term>
 976         <listitem>
 977           <para>Configures how often to sample the packet rate used for adaptive Rx/Tx coalescing. This
 978           property cannot be zero. This lowest time granularity supported by this property is seconds.
 979           Partial seconds will be rounded up before being passed to the kernel. If unset, the kernel's
 980           default will be used.</para>
 981         </listitem>
 982       </varlistentry>
 983       <varlistentry>
 984         <term><varname>StatisticsBlockCoalesceSec=</varname></term>
 985         <listitem>
 986           <para>How long to delay driver in-memory statistics block updates. If the driver does not have an
 987           in-memory statistic block, this property is ignored. This property cannot be zero. If unset, the
 988           kernel's default will be used.</para>
 989         </listitem>
 990       </varlistentry>
 991
 992       <varlistentry>
 993         <term><varname>MDI=</varname></term>
 994         <listitem>
 995           <para>Specifies the medium dependent interface (MDI) mode for the interface. A MDI describes
 996           the interface from a physical layer implementation to the physical medium used to carry the
 997           transmission. Takes one of the following words: <literal>straight</literal> (or equivalently:
 998           <literal>mdi</literal>), <literal>crossover</literal> (or equivalently:
 999           <literal>mdi-x</literal>, <literal>mdix</literal>), and <literal>auto</literal>. When
1000           <literal>straight</literal>, the MDI straight through mode will be used. When
1001           <literal>crossover</literal>, the MDI crossover (MDI-X) mode will be used. When
1002           <literal>auto</literal>, the MDI status is automatically detected. Defaults to unset, and the
1003           kernel's default will be used.</para>
1004         </listitem>
1005       </varlistentry>
1006
1007       <varlistentry>
1008         <term><varname>SR-IOVVirtualFunctions=</varname></term>
1009         <listitem>
1010           <para>Specifies the number of SR-IOV virtual functions. Takes an integer in the range
1011           0…2147483647. Defaults to unset, and automatically determined from the values specified in
1012           the <varname>VirtualFunction=</varname> settings in the [SR-IOV] sections.</para>
1013         </listitem>
1014       </varlistentry>
1015
1016     </variablelist>
1017   </refsect1>
1018
1019   <refsect1 id='sr-iov'>
1020     <title>[SR-IOV] Section Options</title>
1021     <para>The [SR-IOV] section accepts the following keys. Specify several [SR-IOV] sections to
1022     configure several SR-IOVs. SR-IOV provides the ability to partition a single physical PCI resource
1023     into virtual PCI functions which can then be injected into a VM. In the case of network VFs, SR-IOV
1024     improves north-south network performance (that is, traffic with endpoints outside the host machine)
1025     by allowing traffic to bypass the host machine’s network stack.</para>
1026
1027     <variablelist class='network-directives'>
1028       <varlistentry>
1029         <term><varname>VirtualFunction=</varname></term>
1030         <listitem>
1031           <para>Specifies a Virtual Function (VF), lightweight PCIe function designed solely to move
1032           data in and out. Takes an integer in the range 0…2147483646. This option is compulsory.
1033           </para>
1034         </listitem>
1035       </varlistentry>
1036
1037       <varlistentry>
1038         <term><varname>VLANId=</varname></term>
1039         <listitem>
1040           <para>Specifies VLAN ID of the virtual function. Takes an integer in the range 1…4095.</para>
1041         </listitem>
1042       </varlistentry>
1043
1044       <varlistentry>
1045         <term><varname>QualityOfService=</varname></term>
1046         <listitem>
1047           <para>Specifies quality of service of the virtual function. Takes an integer in the range
1048           1…4294967294.</para>
1049         </listitem>
1050       </varlistentry>
1051
1052       <varlistentry>
1053         <term><varname>VLANProtocol=</varname></term>
1054         <listitem>
1055           <para>Specifies VLAN protocol of the virtual function. Takes <literal>802.1Q</literal> or
1056           <literal>802.1ad</literal>.</para>
1057         </listitem>
1058       </varlistentry>
1059
1060       <varlistentry>
1061         <term><varname>MACSpoofCheck=</varname></term>
1062         <listitem>
1063           <para>Takes a boolean. Controls the MAC spoof checking. When unset, the kernel's default will
1064           be used.</para>
1065         </listitem>
1066       </varlistentry>
1067
1068       <varlistentry>
1069         <term><varname>QueryReceiveSideScaling=</varname></term>
1070         <listitem>
1071           <para>Takes a boolean. Toggle the ability of querying the receive side scaling (RSS)
1072           configuration of the virtual function (VF). The VF RSS information like RSS hash key may be
1073           considered sensitive on some devices where this information is shared between VF and the
1074           physical function (PF). When unset, the kernel's default will be used.</para>
1075         </listitem>
1076       </varlistentry>
1077
1078       <varlistentry>
1079         <term><varname>Trust=</varname></term>
1080         <listitem>
1081           <para>Takes a boolean. Allows one to set trust mode of the virtual function (VF). When set,
1082           VF users can set a specific feature which may impact security and/or performance. When unset,
1083           the kernel's default will be used.</para>
1084         </listitem>
1085       </varlistentry>
1086
1087       <varlistentry>
1088         <term><varname>LinkState=</varname></term>
1089         <listitem>
1090           <para>Allows one to set the link state of the virtual function (VF). Takes a boolean or a
1091           special value <literal>auto</literal>. Setting to <literal>auto</literal> means a
1092           reflection of the physical function (PF) link state, <literal>yes</literal> lets the VF to
1093           communicate with other VFs on this host even if the PF link state is down,
1094           <literal>no</literal> causes the hardware to drop any packets sent by the VF. When unset,
1095           the kernel's default will be used.</para>
1096         </listitem>
1097       </varlistentry>
1098
1099       <varlistentry>
1100         <term><varname>MACAddress=</varname></term>
1101         <listitem>
1102           <para>Specifies the MAC address for the virtual function.</para>
1103         </listitem>
1104       </varlistentry>
1105     </variablelist>
1106   </refsect1>
1107
1108   <refsect1>
1109     <title>Examples</title>
1110
1111     <example>
1112       <title>/usr/lib/systemd/network/99-default.link</title>
1113
1114       <para>The link file <filename>99-default.link</filename> that is shipped with systemd defines the
1115       default policies for the interface name, alternative names, and MAC address of links.</para>
1116
1117       <programlisting>[Match]
1118 OriginalName=*
1119
1120 [Link]
1121 NamePolicy=keep kernel database onboard slot path
1122 AlternativeNamesPolicy=database onboard slot path
1123 MACAddressPolicy=persistent</programlisting>
1124     </example>
1125
1126     <example>
1127       <title>/etc/systemd/network/10-dmz.link</title>
1128
1129       <para>This example assigns the fixed name <literal>dmz0</literal> to the interface with the MAC address
1130       00:a0:de:63:7a:e6:</para>
1131
1132       <programlisting>[Match]
1133 MACAddress=00:a0:de:63:7a:e6
1134
1135 [Link]
1136 Name=dmz0</programlisting>
1137
1138       <para><varname>NamePolicy=</varname> is not set, so <varname>Name=</varname> takes effect. We use the
1139       <literal>10-</literal> prefix to order this file early in the list. Note that it needs to be before
1140       <filename>99-default.link</filename>, i.e. it needs a numerical prefix, to have any effect at all.</para>
1141     </example>
1142
1143     <example>
1144       <title>Debugging <varname>NamePolicy=</varname> assignments</title>
1145
1146       <programlisting>$ sudo SYSTEMD_LOG_LEVEL=debug udevadm test-builtin net_setup_link /sys/class/net/hub0
1147 …
1148 Parsed configuration file /usr/lib/systemd/network/99-default.link
1149 Parsed configuration file /etc/systemd/network/10-eth0.link
1150 ID_NET_DRIVER=cdc_ether
1151 Config file /etc/systemd/network/10-eth0.link applies to device hub0
1152 link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
1153 hub0: Device has name_assign_type=4
1154 Using default interface naming scheme 'v240'.
1155 hub0: Policies didn't yield a name, using specified Name=hub0.
1156 ID_NET_LINK_FILE=/etc/systemd/network/10-eth0.link
1157 ID_NET_NAME=hub0
1158 …</programlisting>
1159
1160      <para>Explicit <varname>Name=</varname> configuration wins in this case.</para>
1161
1162      <programlisting>sudo SYSTEMD_LOG_LEVEL=debug udevadm test-builtin net_setup_link /sys/class/net/enp0s31f6
1163 …
1164 Parsed configuration file /usr/lib/systemd/network/99-default.link
1165 Parsed configuration file /etc/systemd/network/10-eth0.link
1166 Created link configuration context.
1167 ID_NET_DRIVER=e1000e
1168 Config file /usr/lib/systemd/network/99-default.link applies to device enp0s31f6
1169 link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
1170 enp0s31f6: Device has name_assign_type=4
1171 Using default interface naming scheme 'v240'.
1172 enp0s31f6: Policy *keep*: keeping existing userspace name
1173 enp0s31f6: Device has addr_assign_type=0
1174 enp0s31f6: MAC on the device already matches policy *persistent*
1175 ID_NET_LINK_FILE=/usr/lib/systemd/network/99-default.link
1176 …
1177 </programlisting>
1178
1179      <para>In this case, the interface was already renamed, so the <option>keep</option> policy specified as
1180      the first option in <filename index="false">99-default.link</filename> means that the existing name is
1181      preserved. If <option>keep</option> was removed, or if were in boot before the renaming has happened,
1182      we might get the following instead:</para>
1183
1184      <programlisting>enp0s31f6: Policy *path* yields "enp0s31f6".
1185 enp0s31f6: Device has addr_assign_type=0
1186 enp0s31f6: MAC on the device already matches policy *persistent*
1187 ID_NET_LINK_FILE=/usr/lib/systemd/network/99-default.link
1188 ID_NET_NAME=enp0s31f6
1189 …
1190 </programlisting>
1191
1192       <para>Please note that the details of output are subject to change.</para>
1193     </example>
1194
1195     <example>
1196       <title>/etc/systemd/network/10-internet.link</title>
1197
1198       <para>This example assigns the fixed name
1199       <literal>internet0</literal> to the interface with the device
1200       path <literal>pci-0000:00:1a.0-*</literal>:</para>
1201
1202       <programlisting>[Match]
1203 Path=pci-0000:00:1a.0-*
1204
1205 [Link]
1206 Name=internet0</programlisting>
1207     </example>
1208
1209     <example>
1210       <title>/etc/systemd/network/25-wireless.link</title>
1211
1212       <para>Here's an overly complex example that shows the use of a large number of [Match] and [Link] settings.</para>
1213
1214       <programlisting>[Match]
1215 MACAddress=12:34:56:78:9a:bc
1216 Driver=brcmsmac
1217 Path=pci-0000:02:00.0-*
1218 Type=wlan
1219 Virtualization=no
1220 Host=my-laptop
1221 Architecture=x86-64
1222
1223 [Link]
1224 Name=wireless0
1225 MTUBytes=1450
1226 BitsPerSecond=10M
1227 WakeOnLan=magic
1228 MACAddress=cb:a9:87:65:43:21</programlisting>
1229     </example>
1230   </refsect1>
1231
1232   <refsect1>
1233     <title>See Also</title>
1234     <para>
1235       <citerefentry>
1236         <refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum>
1237       </citerefentry>,
1238       <citerefentry>
1239         <refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
1240       </citerefentry>,
1241       <citerefentry>
1242         <refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum>
1243       </citerefentry>,
1244       <citerefentry>
1245         <refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum>
1246       </citerefentry>,
1247       <citerefentry>
1248         <refentrytitle>systemd-network-generator.service</refentrytitle><manvolnum>8</manvolnum>
1249       </citerefentry>
1250     </para>
1251   </refsect1>
1252
1253 </refentry>