modularized all the things

part one (?)

modules/networking/dns.nix

@@ -0,0 +1,133 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}: let
+  cfg = config.dns;
+in {
+  options.dns = {
+    bind = {
+      enable = lib.mkEnableOption "BIND DNS server";
+      settings = {
+        interfaces = lib.mkOption {
+          type = lib.types.listOf lib.types.str;
+          default = ["127.0.0.1"];
+          description = "Network interfaces BIND should listen on";
+        };
+
+        zones = lib.mkOption {
+          type = lib.types.listOf (lib.types.submodule {
+            options = {
+              name = lib.mkOption {
+                type = lib.types.str;
+                description = "Name of the DNS zone";
+              };
+              type = lib.mkOption {
+                type = lib.types.enum ["master" "slave"];
+                default = "master";
+                description = "Type of DNS zone";
+              };
+              file = lib.mkOption {
+                type = lib.types.str;
+                default = "";
+                description = "Path to zone file";
+              };
+            };
+          });
+          default = [];
+          description = "DNS zones to configure";
+        };
+
+        extraConfig = lib.mkOption {
+          type = lib.types.lines;
+          default = "";
+          description = "Additional BIND configuration options";
+        };
+      };
+    };
+
+    technitium = {
+      enable = lib.mkEnableOption "Technitium DNS server";
+      settings = {
+        address = lib.mkOption {
+          type = lib.types.str;
+          default = "0.0.0.0";
+          description = "IP address Technitium should listen on";
+        };
+        port = lib.mkOption {
+          type = lib.types.port;
+          default = 5380;
+          description = "Port for Technitium DNS server";
+        };
+        extraOptions = lib.mkOption {
+          type = lib.types.attrs;
+          default = {};
+          description = "Additional Technitium configuration options";
+        };
+      };
+    };
+  };
+
+  # Validate that only one DNS server is enabled
+  imports = [
+    (lib.mkIf (cfg.bind.enable && cfg.technitium.enable) (throw "Only one DNS server can be enabled at a time"))
+  ];
+
+  # Implementation of the configuration
+  config = lib.mkMerge [
+    # BIND DNS Server Configuration
+    (lib.mkIf cfg.bind.enable {
+      services.named = {
+        enable = true;
+        interfaces = cfg.bind.settings.interfaces;
+        zones =
+          map (zone: {
+            name = zone.name;
+            type = zone.type;
+            file = zone.file;
+          })
+          cfg.bind.settings.zones;
+        extraConfig = cfg.bind.settings.extraConfig;
+      };
+      networking.firewall = {
+        allowedTCPPorts = [53];
+        allowedUDPPorts = [53];
+      };
+      environment.systemPackages = [pkgs.bind];
+    })
+
+    # Technitium DNS Server Configuration
+    (lib.mkIf cfg.technitium.enable {
+      # Create a systemd service for Technitium
+      systemd.services.technitium-dns = {
+        description = "Technitium DNS Server";
+        wantedBy = ["multi-user.target"];
+
+        serviceConfig = {
+          ExecStart = "${pkgs.technitium}/bin/dns-server-start.sh";
+          Restart = "on-failure";
+        };
+
+        # Environment configuration
+        environment =
+          {
+            DNS_LISTEN_ADDRESS = cfg.technitium.settings.address;
+            DNS_LISTEN_PORT = toString cfg.technitium.settings.port;
+          }
+          // lib.mapAttrs' (
+            name: value:
+              lib.nameValuePair "DNS_${lib.toUpper name}" (toString value)
+          )
+          cfg.technitium.settings.extraOptions;
+      };
+
+      networking.firewall = {
+        allowedTCPPorts = [cfg.technitium.settings.port];
+        allowedUDPPorts = [cfg.technitium.settings.port];
+      };
+
+      environment.systemPackages = [pkgs.technitium];
+    })
+  ];
+}