path: root/man/NetworkManager-dispatcher.xml

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  SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later

  NetworkManager-dispatcher(8) manual page

  Copyright 2005 - 2016 Red Hat, Inc.
  Copyright 2005 - 2009 Novell, Inc.
  Copyright 2005 Robert Love
-->

<refentry id="NetworkManager-dispatcher">
  <refentryinfo>
    <title>NetworkManager-dispatcher</title>
    <author>NetworkManager developers</author>
  </refentryinfo>
  <refmeta>
    <refentrytitle>NetworkManager-dispatcher</refentrytitle>
    <manvolnum>8</manvolnum>
    <refmiscinfo class="source">NetworkManager-dispatcher</refmiscinfo>
    <refmiscinfo class="manual">Network management daemons</refmiscinfo>
    <refmiscinfo class="version">&NM_VERSION;</refmiscinfo>
  </refmeta>

  <refnamediv>
    <refname>NetworkManager-dispatcher</refname>
    <refpurpose>Dispatch user scripts for NetworkManager</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>NetworkManager <arg choice="opt" rep="repeat">OPTIONS</arg></command>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>
    <para>
      NetworkManager-dispatcher service is a D-Bus activated service that
      runs user provided scripts upon certain changes in NetworkManager.
    </para>
    <para>
      NetworkManager-dispatcher will execute scripts in the
      <filename>/{etc,usr/lib}/NetworkManager/dispatcher.d</filename>
      directory or subdirectories in
      alphabetical order in response to network events.  Each script should
      be a regular executable file owned by root.  Furthermore, it must not be
      writable by group or other, and not setuid.
    </para>
    <para>
      Each script receives two arguments, the first being the interface name of the
      device an operation just happened on, and second the action. For device actions,
      the interface is the name of the kernel interface suitable for IP configuration.
      Thus it is either VPN_IP_IFACE, DEVICE_IP_IFACE, or DEVICE_IFACE, as applicable.
      For the <varname>hostname</varname> action the device name is always
      <literal>"none"</literal>. For <varname>connectivity-change</varname> and
      <varname>dns-change</varname> it is empty.
    </para>
    <para>The actions are:</para>
    <variablelist class="dispatcher-options">
      <varlistentry>
        <term><varname>pre-up</varname></term>
        <listitem><para>The interface is connected to the network but is not
        yet fully activated.  Scripts acting on this event must be placed or
        symlinked into the <filename>/etc/NetworkManager/dispatcher.d/pre-up.d</filename>
        directory, and NetworkManager will wait for script execution to complete before
        indicating to applications that the interface is fully activated.
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>up</varname></term>
        <listitem><para>The interface has been activated.</para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>pre-down</varname></term>
        <listitem><para>The interface will be deactivated but has not yet been
        disconnected from the network.  Scripts acting on this event must be
        placed or symlinked into the <filename>/etc/NetworkManager/dispatcher.d/pre-down.d</filename>
        directory, and NetworkManager will wait for script execution to complete
        before disconnecting the interface from its network.  Note that this
        event is not emitted for forced disconnections, like when carrier is
        lost or a wireless signal fades.  It is only emitted when there is
        an opportunity to cleanly handle a network disconnection event.
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>down</varname></term>
        <listitem><para>
          The interface has been deactivated.
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>vpn-pre-up</varname></term>
        <listitem><para>The VPN is connected to the network but is not yet
        fully activated.  Scripts acting on this event must be placed or
        symlinked into the <filename>/etc/NetworkManager/dispatcher.d/pre-up.d</filename>
        directory, and NetworkManager will wait for script execution to complete before
        indicating to applications that the VPN is fully activated.
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>vpn-up</varname></term>
        <listitem><para>
          A VPN connection has been activated.
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>vpn-pre-down</varname></term>
        <listitem><para>The VPN will be deactivated but has not yet been
        disconnected from the network.  Scripts acting on this event must be
        placed or symlinked into the <filename>/etc/NetworkManager/dispatcher.d/pre-down.d</filename>
        directory, and NetworkManager will wait for script execution to complete
        before disconnecting the VPN from its network.  Note that this
        event is not emitted for forced disconnections, like when the VPN
        terminates unexpectedly or general connectivity is lost.  It is only
        emitted when there is an opportunity to cleanly handle a VPN
        disconnection event.
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>vpn-down</varname></term>
        <listitem><para>
          A VPN connection has been deactivated.
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>hostname</varname></term>
        <listitem><para>
          The system hostname has been updated.  Use gethostname(2) to retrieve it.
          The interface name (first argument) is empty and no environment variable is
          set for this action.
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>dhcp4-change</varname></term>
        <listitem><para>
          The DHCPv4 lease has changed (renewed, rebound, etc).
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>dhcp6-change</varname></term>
        <listitem><para>
          The DHCPv6 lease has changed (renewed, rebound, etc).
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>connectivity-change</varname></term>
        <listitem><para>
          The network connectivity state has changed (no connectivity, went online, etc).
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>reapply</varname></term>
        <listitem><para>
          The connection was reapplied on the device.
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>dns-change</varname></term>
        <listitem><para>
            The DNS configuration has changed. This action is raised even if
            NetworkManager is configured to not manage resolv.conf (for example,
            via dns=none). In such case, the dispatch script can discover the
            DNS configuration provided by currently active connections by
            looking at file <filename>/run/NetworkManager/resolv.conf</filename>
        </para></listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>device-add</varname></term>
        <listitem>
          <para>
            This action is called when a connection of type <literal>generic</literal>
            has the <literal>generic.device-handler</literal> property set. The property
            indicates the name of a dispatcher script to be executed in directory
            <filename>/{etc,usr/lib}/NetworkManager/dispatcher.d/device</filename>. Note
            that differently from other actions, only one script is executed.
          </para>
          <para>
            The script needs to perform any action needed to create the device
            for the generic connection. On successful termination, the script
            returns zero. Otherwise, it returns a non-zero value to indicate an
            error. The script can return values to NetworkManager by writing to
            standard output; each line should contain a key name followed by the
            equal sign '=' and a key value. The keys understood at the moment
            are:
            <variablelist>
              <varlistentry>
                <term><varname>IFINDEX</varname></term>
                <listitem><para> Indicates the interface index of the interface
                created by the script. This key is required when the script
                succeeds; if it is not set, the activation will fail. The key is
                ignored in case of script failure. </para></listitem>
              </varlistentry>
              <varlistentry>
                <term><varname>ERROR</varname></term>
                <listitem><para> Specifies an error message indicating the cause
                of the script failure. It is ignored when the script succeeds.
                </para></listitem>
              </varlistentry>
            </variablelist>
            Since the dispatcher service captures stdout for parsing those keys,
            anything written to stdout will not appear in the dispatcher service
            journal log. Use stderr if you want to print messages to the journal
            (for example, for debugging). Only the first 8KiB of stdout are
            considered and among those, only the first 64 lines; the rest is
            ignored.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>device-delete</varname></term>
        <listitem>
          <para>
            This action is the counterpart of <literal>device-add</literal> and
            is called to delete the device for a generic connection. All the
            aspects described for <literal>device-add</literal> also apply to
            this action, with the only exception that key
            <varname>IFINDEX</varname> is ignored. It is not necessary to delete
            the kernel link in the handler because NetworkManager already does
            that; therefore the action is useful for any additional cleanup
            needed.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
    <para>
      The environment contains more information about the interface and the connection.
      The following variables are available for the use in the dispatcher scripts:
      <variablelist class="dispatcher-environment">
        <varlistentry>
          <term><varname>NM_DISPATCHER_ACTION</varname></term>
          <listitem><para>
            The dispatcher action like "up" or "dhcp4-change", identical to the first
            command line argument. Since NetworkManager 1.12.0.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>CONNECTION_UUID</varname></term>
          <listitem><para>
            The UUID of the connection profile.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>CONNECTION_ID</varname></term>
          <listitem><para>
            The name (ID) of the connection profile.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>CONNECTION_DBUS_PATH</varname></term>
          <listitem><para>
            The NetworkManager D-Bus path of the connection.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>CONNECTION_FILENAME</varname></term>
          <listitem><para>
            The backing file name of the connection profile (if any).
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>CONNECTION_EXTERNAL</varname></term>
          <listitem><para>
            If "1", this indicates that the connection describes a
            network configuration created outside of NetworkManager.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DEVICE_IFACE</varname></term>
          <listitem><para>
            The interface name of the control interface of the device.
            Depending on the device type, this differs from
            <varname>DEVICE_IP_IFACE</varname>. For example for
            ADSL devices, this could be 'atm0' or for WWAN devices
            it might be 'ttyUSB0'.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DEVICE_IP_IFACE</varname></term>
          <listitem><para>
            The IP interface name of the device. This is the network
            interface on which IP addresses and routes will be configured.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IP4_ADDRESS_N</varname></term>
          <listitem><para>
            The IPv4 address in the format "address/prefix gateway", where N is a number
            from 0 to (# IPv4 addresses - 1). gateway item in this variable is deprecated,
            use IP4_GATEWAY instead.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IP4_NUM_ADDRESSES</varname></term>
          <listitem><para>
            The variable contains the number of IPv4 addresses the script may expect.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IP4_GATEWAY</varname></term>
          <listitem><para>
            The gateway IPv4 address in traditional numbers-and-dots notation.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IP4_ROUTE_N</varname></term>
          <listitem><para>
            The IPv4 route in the format "address/prefix next-hop metric", where N is a number
            from 0 to (# IPv4 routes - 1).
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IP4_NUM_ROUTES</varname></term>
          <listitem><para>
            The variable contains the number of IPv4 routes the script may expect.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IP4_NAMESERVERS</varname></term>
          <listitem><para>
            The variable contains a space-separated list of the DNS servers.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IP4_DOMAINS</varname></term>
          <listitem><para>
            The variable contains a space-separated list of the search domains.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>DHCP4_&lt;dhcp-option-name&gt;</varname></term>
          <listitem><para>
            If the connection used DHCP for address configuration, the received DHCP
            configuration is passed in the environment using standard DHCP
            option names, prefixed with "DHCP4_", like "DHCP4_HOST_NAME=foobar".
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>IP6_&lt;name&gt; and DHCP6_&lt;name&gt;</varname></term>
          <listitem><para>
            The same variables as for IPv4 are available for IPv6, but the prefixes are IP6_
            and DHCP6_ instead.
          </para></listitem>
        </varlistentry>
        <varlistentry>
          <term><varname>CONNECTIVITY_STATE</varname></term>
          <listitem><para> The network connectivity state, which can
          take the values defined by the NMConnectivityState type,
          from the org.freedesktop.NetworkManager D-Bus API: <literal>UNKNOWN</literal>,
          <literal>NONE</literal>, <literal>PORTAL</literal>, <literal>LIMITED</literal>
          or <literal>FULL</literal>. Note: this variable will only
          be set for connectivity-change actions.
          </para></listitem>
        </varlistentry>
      </variablelist>
    </para>
    <para>
      In case of VPN, VPN_IP_IFACE is set, and IP4_*, IP6_* variables with VPN prefix are
      exported too, like VPN_IP4_ADDRESS_0, VPN_IP4_NUM_ADDRESSES.
    </para>
    <para>
      The content of the <literal>user</literal> setting for the connection
      being activated is also passed via environment variables. Each key is
      stored in a variable with name <literal>CONNECTION_USER_</literal>
      concatenated with the encoding of the key name. The encoding works as
      follows:
      <itemizedlist>
        <listitem>
          <para>lowercase letters become uppercase</para>
        </listitem>
        <listitem>
          <para>uppercase letters are prefixed with an underscore</para>
        </listitem>
        <listitem>
          <para>numbers do not change</para>
        </listitem>
        <listitem>
          <para>a dot is replaced with a double underscore</para>
        </listitem>
        <listitem>
          <para>any other character is encoded with an underscore followed by
          its 3-digit octal representation</para>
        </listitem>
      </itemizedlist>
      For example, key <literal>test.foo-Bar2</literal> is stored in a variable named
      <literal>CONNECTION_USER_TEST__FOO_055_BAR2</literal>.
    </para>
    <para>
      Dispatcher scripts are run one at a time, but asynchronously from the main
      NetworkManager process, and will be killed if they run for too long. If your script
      might take arbitrarily long to complete, you should spawn a child process and have the
      parent return immediately. Scripts that are symbolic links pointing inside the
      <filename>/etc/NetworkManager/dispatcher.d/no-wait.d/</filename>
      directory are run immediately, without
      waiting for the termination of previous scripts, and in parallel. Also beware that
      once a script is queued, it will always be run, even if a later event renders it
      obsolete. (Eg, if an interface goes up, and then back down again quickly, it is
      possible that one or more "up" scripts will be run after the interface has gone down.)
    </para>
  </refsect1>

  <refsect1>
    <title>Bugs</title>
    <para>
      Please report any bugs you find in NetworkManager at the
      <ulink url="https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues">NetworkManager issue tracker</ulink>.
    </para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <ulink url="https://networkmanager.dev">NetworkManager home page</ulink>,
      <link linkend='NetworkManager'><citerefentry><refentrytitle>NetworkManager</refentrytitle><manvolnum>8</manvolnum></citerefentry></link>,
    </para>
  </refsect1>
</refentry>