add possibility of DMZ connectivity on hypervisor

nixos/machines/default.nix

@@ -39,6 +39,7 @@
     nixosModule.lab = {
       disko.osDiskDevice = "/dev/sda";
       backups.enable = true;
+      networking.allowDMZConnectivity = true;
 
       dataDisk = {
         enable = true;

nixos/modules/default.nix

@@ -6,5 +6,6 @@
     ./k3s
     ./disko.nix
     ./backups.nix
+    ./networking.nix
   ];
 }

nixos/modules/networking.nix

@@ -1,4 +1,15 @@
-{
+{ lib, config, ... }:
+let cfg = config.lab.networking;
+in {
+  options.lab.networking.allowDMZConnectivity = lib.mkOption {
+    default = false;
+    type = lib.types.bool;
+    description = ''
+      Whether to create a networking interface on the DMZ bridge.
+    '';
+  };
+
+  config = {
     networking = {
       domain = "hyp";
       firewall.enable = true;
@@ -54,6 +65,8 @@
           networkConfig = {
             IPv6AcceptRA = false;
             LinkLocalAddressing = "no";
+            DHCP = lib.mkIf cfg.allowDMZConnectivity "yes";
+          };
         };
       };
     };