nixos/wvdial: init module

nixos/modules/module-list.nix

@@ -1242,6 +1242,7 @@
   ./services/networking/websockify.nix
   ./services/networking/wg-access-server.nix
   ./services/networking/wg-netmanager.nix
+  ./services/networking/wvdial.nix
   ./services/networking/webhook.nix
   ./services/networking/wg-quick.nix
   ./services/networking/wgautomesh.nix

nixos/modules/services/networking/wvdial.nix

@@ -0,0 +1,47 @@
+# Global configuration for wvdial.
+
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+let
+  cfg = config.environment.wvdial;
+in
+{
+  options = {
+    environment.wvdial = {
+      dialerDefaults = lib.mkOption {
+        default = "";
+        type = lib.types.str;
+        example = ''Init1 = AT+CGDCONT=1,"IP","internet.t-mobile"'';
+        description = ''
+          Contents of the "Dialer Defaults" section of
+          <filename>/etc/wvdial.conf</filename>.
+        '';
+      };
+      pppDefaults = lib.mkOption {
+        default = ''
+          noipdefault
+          usepeerdns
+          defaultroute
+          persist
+          noauth
+        '';
+        type = lib.types.str;
+        description = "Default ppp settings for wvdial.";
+      };
+    };
+  };
+
+  config = lib.mkIf (cfg.dialerDefaults != "") {
+    environment.etc."wvdial.conf".source = pkgs.writeText "wvdial.conf" ''
+      [Dialer Defaults]
+      PPPD PATH = ${pkgs.ppp}/sbin/pppd
+      ${config.environment.wvdial.dialerDefaults}
+    '';
+    environment.etc."ppp/peers/wvdial".source = pkgs.writeText "wvdial" cfg.pppDefaults;
+  };
+}