nixos/state: add ports sub-option

modules/nixos/_private/default.nix

@@ -1,7 +1,7 @@
 {
   imports = [
     ./extra-arguments.nix
-    ./state.nix
+    ./state
     ./suites/archiving.nix
     ./suites/browsers.nix
     ./suites/desktop.nix

modules/nixos/_private/state/default.nix

@@ -1,9 +1,13 @@
 { lib, ... }:
 
 {
+  imports = [
+    ./ports.nix
+  ];
+
   options.state = lib.mkOption {
     type = lib.types.submodule {
-      freeFormType = with lib.types; attrsOf anything;
+      freeformType = with lib.types; attrsOf anything;
       default = { };
     };
     description = ''

modules/nixos/_private/state/ports.nix

@@ -0,0 +1,108 @@
+{ config, lib, ... }:
+
+let
+  cfg = config.state;
+
+  supportedProtocols = [ "tcp" "udp" ];
+
+  portRangeType = {
+    options = {
+      from = lib.mkOption {
+        type = lib.types.port;
+        description = ''
+          The start of the range of TCP/UDP ports to be taken over.
+        '';
+      };
+
+      to = lib.mkOption {
+        type = lib.types.port;
+        description = ''
+          The end of the range of TCP/UDP ports to be taken over.
+        '';
+      };
+    };
+  };
+
+  portModule = { lib, ... }: {
+    options = {
+      protocols = lib.mkOption {
+        type = with lib.types; listOf (enum supportedProtocols);
+        description = ''
+          Indicates the type of protocol of the service.
+        '';
+        default = [ "tcp" "udp" ];
+        example = [ "tcp" ];
+      };
+
+      value = lib.mkOption {
+        type = with lib.types; either port (submodule portRangeType);
+        description = ''
+          The port number itself.
+        '';
+      };
+
+      openFirewall = lib.mkEnableOption "opening the ports to firewall";
+    };
+  };
+in
+{
+  options.state =
+    let
+      portsModule = { lib, ... }: {
+        options = {
+          ports = lib.mkOption {
+            type = with lib.types; attrsOf (submodule portModule);
+            description = ''
+              A set of ports indicating what goes where in the NixOS system.
+            '';
+            example = lib.literalExpression ''
+              rec {
+                gonic = {
+                  value = 5757;
+                  protocols = [ "tcp" ];
+                  openFirewall = true;
+                };
+                uxplay = {
+                  value = 7864;
+                  openFirewall = true;
+                };
+                uxplayClients.value = {
+                  from = uxplay.value + 1;
+                  to = uxplay.value + 20;
+                };
+              }
+            '';
+          };
+        };
+      };
+    in lib.mkOption {
+      type = lib.types.submodule portsModule;
+    };
+
+  config = lib.mkIf (cfg.ports != { }) {
+    networking.firewall =
+      let
+        allPortsToBeOpened = lib.filterAttrs (_: v: v.openFirewall) cfg.ports;
+        hasProtocol = protocol: v: lib.elem protocol v.protocols;
+        mkFirewallEntry = protocol: v:
+          let
+            inherit (v) value;
+          in
+          if lib.isAttrs value then {
+            ${if protocol == "tcp"
+              then "allowedTCPPortRanges"
+              else "allowedUDPPortRanges"} = [ value ];
+          } else {
+            ${if protocol == "tcp"
+              then "allowedTCPPorts"
+              else "allowedUDPPorts"} = [ value ];
+          };
+
+        mkFirewallEntryModule = _: v:
+          lib.optionalAttrs (hasProtocol "udp" v) (mkFirewallEntry "udp" v)
+          // lib.optionalAttrs (hasProtocol "tcp" v) (mkFirewallEntry "tcp" v);
+      in
+      lib.mkMerge
+        (lib.mapAttrsToList mkFirewallEntryModule allPortsToBeOpened);
+  };
+}