Add networking lib

lib/default.nix

@@ -6,4 +6,5 @@
 }: {
   nixos = import ./nixos.nix {inherit inputs pkgs lib;};
   modules = import ./modules.nix {inherit inputs pkgs lib;};
+  networking = import ./networking.nix {inherit inputs pkgs lib;};
 }

lib/networking.nix

@@ -0,0 +1,84 @@
+{
+  inputs,
+  pkgs,
+  lib,
+  ...
+}: rec {
+  mkSystemdNetwork = interface: {
+    # name = "enp0s31f6"; # Network interface name?
+    enable = true;
+
+    # See man systemd.link, man systemd.netdev, man systemd.network
+    matchConfig = {
+      # This corresponds to the [MATCH] section
+      Name = interface; # Match ethernet interface
+    };
+
+    # See man systemd.network
+    networkConfig = {
+      # This corresponds to the [NETWORK] section
+      DHCP = "yes";
+
+      # TODO: What does this all do?
+      # IPv6AcceptRA = true;
+      # MulticastDNS = "yes"; # Needed?
+      # LLMNR = "no"; # Needed?
+      # LinkLocalAddressing = "no"; # Needed?
+    };
+
+    linkConfig = {
+      # This corresponds to the [LINK] section
+      # RequiredForOnline = "routable";
+    };
+  };
+
+  # VPN stuff
+  mkNetworkNamespace = name: ''
+    ${pkgs.iproute}/bin/ip netns add ${name} # Create the Namespace
+    ${pkgs.iproute}/bin/ip -n ${name} link set lo up # Enable the Loopback device
+  '';
+
+  killNetworkNamespace = name: ''
+    ${pkgs.iproute}/bin/ip netns del ${name} # Delete the Namespace
+  '';
+
+  # TODO: IPv6 Configuration
+  # NOTE: The interface and netns have the same name, so it's a bit confusing
+  mkWireguardTunnel = name: privatekey: publickey: endpoint: ''
+    ${pkgs.iproute}/bin/ip link add ${name} type wireguard
+    ${pkgs.iproute}/bin/ip link set ${name} netns ${name}
+    ${pkgs.iproute}/bin/ip netns exec ${name} ${pkgs.wireguard-tools}/bin/wg set ${name} \
+      private-key /home/christoph/.secrets/wireguard/${privatekey} \
+      peer ${publickey} \
+      allowed-ips 0.0.0.0/0 \
+      endpoint ${endpoint}:51820
+    ${pkgs.iproute}/bin/ip -n ${name} addr add 10.2.0.2/32 dev ${name}
+    ${pkgs.iproute}/bin/ip -n ${name} link set ${name} up
+    ${pkgs.iproute}/bin/ip -n ${name} route add default dev ${name}
+  '';
+
+  killWireguardTunnel = name: ''
+    ${pkgs.iproute}/bin/ip -n ${name} link del ${name}
+  '';
+
+  mkWireguardService = name: privatekey: publickey: endpoint: {
+    description = "Wireguard ProtonVPN Server ${name}";
+    serviceConfig = {
+      Type = "oneshot";
+      RemainAfterExit = true;
+      ExecStart = pkgs.writeScript "${name}-up" ''
+        #! ${pkgs.bash}/bin/bash
+        ${mkNetworkNamespace "${name}"}
+        ${mkWireguardTunnel "${name}" "${privatekey}" "${publickey}" "${endpoint}"}
+      '';
+      ExecStop = pkgs.writeScript "wg0-de-115-down" ''
+        #! ${pkgs.bash}/bin/bash
+        ${killWireguardTunnel "${name}"}
+        ${killNetworkNamespace "${name}"}
+      '';
+    };
+  };
+
+  # mkOpenVPNTunnel = "";
+  # killOpenVPNTunnel = "";
+}