frandom: very fast kernel random number generator

svn path=/nixos/trunk/; revision=32084

modules/module-list.nix

@@ -149,6 +149,7 @@
   ./services/scheduling/atd.nix
   ./services/scheduling/cron.nix
   ./services/scheduling/fcron.nix
+  ./services/security/frandom.nix
   ./services/security/tor.nix
   ./services/security/torsocks.nix
   ./services/system/cgroups.nix

modules/services/security/frandom.nix

@@ -0,0 +1,31 @@
+{pkgs, config, ...}:
+
+let kernel = config.boot.kernelPackages;
+in
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.frandom.enable = pkgs.lib.mkOption {
+      default = false;
+      type = pkgs.lib.types.bool;
+      description = ''
+        enable the /dev/frandom device (a very fast random number generator)
+      '';
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = pkgs.lib.mkIf config.services.frandom.enable {
+    boot.kernelModules = [ "frandom" ];
+    boot.extraModulePackages = [ kernel.frandom ];
+    services.udev.packages = [ kernel.frandom ];
+  };
+
+}