owamp: adding module

You can retrieve the one way latency between your client and the remote
host via owping.

nixos/modules/module-list.nix

@@ -536,6 +536,7 @@
   ./services/networking/openntpd.nix
   ./services/networking/openvpn.nix
   ./services/networking/ostinato.nix
+  ./services/networking/owamp.nix
   ./services/networking/pdnsd.nix
   ./services/networking/polipo.nix
   ./services/networking/powerdns.nix

nixos/modules/services/networking/owamp.nix

@@ -0,0 +1,47 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.owamp;
+in
+{
+
+  ###### interface
+
+  options = {
+    services.owamp.enable = mkEnableOption ''Enable OWAMP server'';
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+    users.extraUsers = singleton {
+      name = "owamp";
+      group = "owamp";
+      description = "Owamp daemon";
+    };
+
+    users.extraGroups = singleton {
+      name = "owamp";
+    };
+
+    systemd.services.owamp = {
+      description = "Owamp server";
+      wantedBy = [ "multi-user.target" ];
+
+      serviceConfig = {
+        ExecStart="${pkgs.owamp}/bin/owampd -R /run/owamp -d /run/owamp -v -Z ";
+        PrivateTmp = true;
+        Restart = "always";
+        Type="simple";
+        User = "owamp";
+        Group = "owamp";
+        RuntimeDirectory = "owamp";
+        StateDirectory = "owamp";
+        AmbientCapabilities = "cap_net_bind_service";
+      };
+    };
+  };
+}