networking: replace dummy interface hack with ifplugd service

4 files changed, 40 insertions, 21 deletions

diff --git a/config/networking/bridges.nix b/config/networking/bridges.nix
index d8cd9e7..e423e03 100644
--- a/config/networking/bridges.nix
+++ b/config/networking/bridges.nix
@@ -12,21 +12,6 @@ in {
           sleep 3
         '');
       }
-      {
-        # create a bridge on top of enp3s0 along with a dummy interface
-        # for kea to work even when enp3s0 is disconnected
-        # if you change this, you may want to change:
-        # - the kea configuration in ./services/dhcp.nix
-        # - the eth0 net configuration ./default.nix
-        networking = {
-          bridges.eth0.interfaces = ["enp3s0" "enp3s0-dummy"];
-          localCommands = ''
-            ip link add enp3s0-dummy type dummy
-          '';
-        };
-        boot.kernelModules = ["dummy"];
-        systemd.services.network-addresses-enp3s0-dummy.enable = false;
-      }
     ]
     ++ (builtins.map (network: let
       bridge = network.interface;
diff --git a/config/networking/default.nix b/config/networking/default.nix
index 7ffc32b..81efaf2 100644
--- a/config/networking/default.nix
+++ b/config/networking/default.nix
@@ -95,7 +95,7 @@ in {
         };
         eth0 = {
           device = "enp3s0";
-          interface = "eth0";
+          interface = "enp3s0";
           subnet = "192.168.4";
           machines = {
             self.ip = "192.168.4.1";
diff --git a/config/networking/services/default.nix b/config/networking/services/default.nix
index 0ec9540..623a1c7 100644
--- a/config/networking/services/default.nix
+++ b/config/networking/services/default.nix
@@ -1,6 +1,3 @@
-{ ... }:
-
-{
-  imports =
-    [ ./ap.nix ./dhcp.nix ./dns.nix ./firewall ./igmpproxy.nix ];
+{...}: {
+  imports = [./ap.nix ./dhcp.nix ./dns.nix ./firewall ./ifplugd.nix ./igmpproxy.nix];
 }
diff --git a/config/networking/services/ifplugd.nix b/config/networking/services/ifplugd.nix
new file mode 100644
index 0000000..4933b97
--- /dev/null
+++ b/config/networking/services/ifplugd.nix
@@ -0,0 +1,37 @@
+{
+  config,
+  pkgs,
+  ...
+}: let
+  iface = config.personal.networking.networks.eth0.device;
+  dhcpService = "kea-dhcp4-server.service";
+  action = pkgs.writeShellApplication {
+    name = "ifplugd-enp3s0.action";
+    runtimeInputs = [pkgs.systemd];
+    text = ''
+      INTERFACE="$1"
+      EVENT="$2"
+
+      if [[ "$INTERFACE" == '${iface}' && "$EVENT" == up ]]
+      then
+        echo ${iface} went up, restarting ${dhcpService}...
+        systemctl restart ${dhcpService}
+      fi
+    '';
+  };
+in {
+  systemd.services."ifplugd-${iface}" = {
+    enable = true;
+
+    description = "Monitor status of interface ${iface}";
+    after = ["sys-subsystem-net-devices-${iface}.device" dhcpService];
+    wantedBy = [dhcpService];
+
+    script = ''
+      #       iface       no-daemon no-auto no-shutdown delay-up run
+      ifplugd -i ${iface} -n        -a      -q          -u 5     -r \
+              ${action}/bin/ifplugd-enp3s0.action
+    '';
+    path = [pkgs.busybox];
+  };
+}