Systemd/networkd/dispatcher: Difference between revisions

Revision as of 19:32, 8 March 2023

Networkd-dispatcher is a dispatcher service for systemd-networkd connection status changes. This daemon is similar to NetworkManager-dispatcher, but is much more limited in the types of events it supports due to the limited nature of systemd-networkd.

Note: Parts of this instruction and module are not yet stable and will be available in the upcoming NixOS 23.05 release.

Usage

The following example triggers a script every time the networkd state routable or off is reached. This is the case when you connect to a new network or quit an existing connection as with OpenVPN. An additional check ensures that the affected interface corresponds to wlan0 and that the uplink is configured. After that the Tor daemon gets restarted.

services.networkd-dispatcher = {
  enable = true;
  rules."restart-tor" = {
    onState = ["routable" "off"];
    script = ''
      #!${pkgs.runtimeShell}
      if [[ $IFACE == "wlan0" && $AdministrativeState == "configured" ]]; then
        echo "Restarting Tor ..."
        systemctl restart tor
      fi
      exit 0
    '';
  };
};

Please refer upstream documentation for configuration syntax and additional examples.

@@ Line 3: / Line 3: @@
 {{Note|Parts of this instruction and module are not yet stable and will be available in the upcoming NixOS 23.05 release.}}
-== Installation ==
+== Usage ==
-Add following line to your system configuration to install and enable Networkd-dispatcher
+The following example triggers a script every time the networkd state <code>routable</code> or <code>off</code> is reached. This is the case when you connect to a new network or quit an existing connection as with [[OpenVPN]]. An additional check ensures that the affected interface corresponds to <code>wlan0</code> and that the uplink is <code>configured</code>. After that the [[Tor]] daemon gets restarted.
 <syntaxhighlight lang="nix">
-services.networkd-dispatcher.enable = true;
+services.networkd-dispatcher = {
-</syntaxhighlight>
+  enable = true;
+  rules."restart-tor" = {
-== Configuration ==
+    onState = ["routable" "off"];
+    script = ''
-In the following example we're going to create a script which will restart the [[Tor]] daemon everytime the interface <code>wlan0</code> establishes a new successfull connection to a wifi network.
+      #!${pkgs.runtimeShell}
+      if [[ $IFACE == "wlan0" && $AdministrativeState == "configured" ]]; then
-{{file|/var/lib/networkd-dispatcher/routable.d/00-restart-tor.sh|bash|<nowiki>
+        echo "Restarting Tor ..."
-#!/usr/bin/env bash
+        systemctl restart tor
-if [[ $IFACE == "wlan0" && $AdministrativeState == "configured" ]]; then
+      fi
-    systemctl restart tor
+      exit 0
-fi
+    '';
-exit 0
+  };
-</nowiki>}}
+};
-Adjusting file permissions for the script to work
-<syntaxhighlight lang="bash">
-chmod 755 /var/lib/networkd-dispatcher/routable.d/00-restart-tor
-chown root /var/lib/networkd-dispatcher/routable.d/00-restart-tor
 </syntaxhighlight>