Add raccoon peer to wireguard

It routes traffic from fox, apex and the compute nodes so that we can
reach the git servers and tent.

Reviewed-by: Aleix Boné <abonerib@bsc.es>

m/raccoon/configuration.nix

@@ -8,6 +8,7 @@
     ../module/ssh-hut-extern.nix
     ../module/nvidia.nix
     ../eudy/kernel/perf.nix
+    ./wireguard.nix
   ];
 
   # Don't install Grub on the disk yet

m/raccoon/wireguard.nix

@@ -0,0 +1,48 @@
+{ config, pkgs, ... }:
+
+{
+  networking.nat = {
+    enable = true;
+    enableIPv6 = false;
+    externalInterface = "eno0";
+    internalInterfaces = [ "wg0" ];
+  };
+
+  networking.firewall = {
+    allowedUDPPorts = [ 666 ];
+  };
+
+  age.secrets.wgRaccoon.file = ../../secrets/wg-raccoon.age;
+
+  # Enable WireGuard
+  networking.wireguard.enable = true;
+  networking.wireguard.interfaces = {
+    wg0 = {
+      ips = [ "10.106.0.236/24" ];
+      listenPort = 666;
+      privateKeyFile = config.age.secrets.wgRaccoon.path;
+      # Public key: QUfnGXSMEgu2bviglsaSdCjidB51oEDBFpnSFcKGfDI=
+      peers = [
+        {
+          name = "fox";
+          publicKey = "VfMPBQLQTKeyXJSwv8wBhc6OV0j2qAxUpX3kLHunK2Y=";
+          allowedIPs = [ "10.106.0.1/32" ];
+          endpoint = "fox.ac.upc.edu:666";
+          persistentKeepalive = 25;
+        }
+        {
+          name = "apex";
+          publicKey = "VwhcN8vSOzdJEotQTpmPHBC52x3Hbv1lkFIyKubrnUA=";
+          allowedIPs = [ "10.106.0.30/32" "10.0.40.0/24" ];
+          endpoint = "ssfhead.bsc.es:666";
+          persistentKeepalive = 25;
+        }
+      ];
+    };
+  };
+
+  networking.hosts = {
+    "10.106.0.1"  = [ "fox.wg" ];
+    "10.106.0.30" = [ "apex.wg" ];
+  };
+}