1 files changed, 63 insertions, 0 deletions
diff --git a/nixos/modules/services/networking/ferm.nix b/nixos/modules/services/networking/ferm.nix
new file mode 100644
index 00000000000..8e03f30efc0
--- /dev/null
+++ b/nixos/modules/services/networking/ferm.nix
@@ -0,0 +1,63 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.ferm;
+
+  configFile = pkgs.stdenv.mkDerivation {
+    name = "ferm.conf";
+    text = cfg.config;
+    preferLocalBuild = true;
+    buildCommand = ''
+      echo -n "$text" > $out
+      ${cfg.package}/bin/ferm --noexec $out
+    '';
+  };
+in {
+  options = {
+    services.ferm = {
+      enable = mkOption {
+        default = false;
+        type = types.bool;
+        description = ''
+          Whether to enable Ferm Firewall.
+          *Warning*: Enabling this service WILL disable the existing NixOS
+          firewall! Default firewall rules provided by packages are not
+          considered at the moment.
+        '';
+      };
+      config = mkOption {
+        description = "Verbatim ferm.conf configuration.";
+        default = "";
+        defaultText = literalDocBook "empty firewall, allows any traffic";
+        type = types.lines;
+      };
+      package = mkOption {
+        description = "The ferm package.";
+        type = types.package;
+        default = pkgs.ferm;
+        defaultText = literalExpression "pkgs.ferm";
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.firewall.enable = false;
+    systemd.services.ferm = {
+      description = "Ferm Firewall";
+      after = [ "ipset.target" ];
+      before = [ "network-pre.target" ];
+      wants = [ "network-pre.target" ];
+      wantedBy = [ "multi-user.target" ];
+      reloadIfChanged = true;
+      serviceConfig = {
+        Type="oneshot";
+        RemainAfterExit = "yes";
+        ExecStart = "${cfg.package}/bin/ferm ${configFile}";
+        ExecReload = "${cfg.package}/bin/ferm ${configFile}";
+        ExecStop = "${cfg.package}/bin/ferm -F ${configFile}";
+      };
+    };
+  };
+}