From 4d93272cb03a7d80027179744aa30fc5617fb829 Mon Sep 17 00:00:00 2001
From: Simon Bruder <simon@sbruder.de>
Date: Fri, 7 Apr 2023 14:14:31 +0200
Subject: [PATCH] wireguard/home: Switch to systemd-networkd

---
 modules/wireguard/home.nix | 82 ++++++++++++++++++++++++--------------
 1 file changed, 52 insertions(+), 30 deletions(-)

diff --git a/modules/wireguard/home.nix b/modules/wireguard/home.nix
index f3920cf..dd37c36 100644
--- a/modules/wireguard/home.nix
+++ b/modules/wireguard/home.nix
@@ -1,6 +1,7 @@
 { lib, config, machines, pkgs, ... }:
 let
   serverHostName = "vueko";
+  serverPort = 51820;
   peers = {
     hitagi = {
       address = "10.80.0.5";
@@ -45,50 +46,71 @@ in
 
   config = lib.mkIf cfg.enable {
     sops.secrets.wg-home-private-key = {
+      owner = config.users.users.systemd-network.name;
       sopsFile = ./../../machines + "/${config.networking.hostName}/secrets.yaml";
     };
 
     sbruder.wireguard.home.address = peers."${config.networking.hostName}".address;
 
-    networking.wireguard.interfaces.wg-home = {
-      privateKeyFile = config.sops.secrets.wg-home-private-key.path;
-      ips = [ "${cfg.address}/24" ];
-      listenPort = if enableServer then 51820 else null;
-      peers =
-        if enableServer
-        then
-          map
-            (peerConfig: with peerConfig; {
-              allowedIPs = [ "${address}/32" ];
-              inherit publicKey;
-            })
-            (lib.attrValues
-              (lib.filterAttrs
-                (n: v: n != config.networking.hostName)
-                peers))
-        else [
-          {
-            allowedIPs = [ "10.80.0.0/24" ];
-            publicKey = peers."${serverHostName}".publicKey;
-            #endpoint = "${serverHostName}.sbruder.de:51820"; # not possible because sadly not all devices have IPv6 connectivity
-            endpoint = "195.201.139.15:51820";
-            persistentKeepalive = 25;
-          }
-        ];
+    systemd.network = {
+      enable = true;
+      netdevs = {
+        wg-home = {
+          netdevConfig = {
+            Kind = "wireguard";
+            Name = "wg-home";
+          };
+          wireguardConfig = {
+            PrivateKeyFile = config.sops.secrets.wg-home-private-key.path;
+          } // (lib.optionalAttrs enableServer {
+            ListenPort = serverPort;
+          });
+          wireguardPeers =
+            if enableServer
+            then
+              map
+                (peerConfig: with peerConfig; {
+                  wireguardPeerConfig = {
+                    PublicKey = publicKey;
+                    AllowedIPs = [ "${address}/32" ];
+                  };
+                })
+                (lib.attrValues
+                  (lib.filterAttrs
+                    (n: v: n != config.networking.hostName)
+                    peers))
+            else [
+              {
+                wireguardPeerConfig = {
+                  PublicKey = peers."${serverHostName}".publicKey;
+                  AllowedIPs = [ "10.80.0.0/24" ];
+                  #Endpoint = "${serverHostName}.sbruder.de:${toString serverPort}"; # not possible because sadly not all devices have IPv6 connectivity
+                  Endpoint = "195.201.139.15:${toString serverPort}";
+                  PersistentKeepalive = 25;
+                };
+              }
+            ];
+        };
+      };
+      networks = {
+        wg-home = {
+          name = "wg-home";
+          address = lib.singleton "${config.sbruder.wireguard.home.address}/24";
+          networkConfig = lib.optionalAttrs enableServer {
+            IPForward = "ipv4";
+          };
+        };
+      };
     };
 
     networking.firewall = {
       trustedInterfaces = [ "wg-home" ];
       allowedUDPPorts = lib.optionals enableServer [
-        51820
+        serverPort
         53
       ];
     };
 
-    boot.kernel.sysctl = lib.optionalAttrs enableServer {
-      "net.ipv4.ip_forward" = lib.mkOverride 999 1;
-    };
-
     services.bind = lib.mkIf enableServer {
       enable = true;
       zones = lib.singleton {