adding support for openvpn daemon client and/or server

svn path=/nixos/branches/modular-nixos/; revision=15421

system/options.nix

@@ -487,6 +487,7 @@ in
     (import ../upstart-jobs/tty-backgrounds.nix)
 
     (import ../upstart-jobs/synergy.nix)
+    (import ../upstart-jobs/openvpn.nix)
 
     (import ../upstart-jobs/nfs-kernel.nix)
     (import ../upstart-jobs/autofs.nix)

upstart-jobs/openvpn.nix

@@ -0,0 +1,130 @@
+
+{pkgs, config, ...}:
+
+###### interface
+let
+  inherit (pkgs.lib) mkOption mkIf;
+
+  options = {
+    services = {
+      openvpn = {
+        enable = mkOption {
+          default = false;
+          description = "
+            Whether to enable the Secure Shell daemon, which allows secure
+            remote logins.
+          ";
+        };
+        servers = mkOption {
+          example = [
+            {
+              id = "server-simplest";
+              config = ''
+                # Most simple configuration: http://openvpn.net/index.php/documentation/miscellaneous/static-key-mini-howto.html.
+                # server : 
+                dev tun
+                ifconfig 10.8.0.1 10.8.0.2
+                secret static.key
+              '';
+              up = "ip route add ..!";
+              down = "ip route add ..!";
+            }
+            {
+              id = "client-simplest";
+              config = ''
+                #client:
+                #remote myremote.mydomain
+                #dev tun
+                #ifconfig 10.8.0.2 10.8.0.1
+                #secret static.key
+              '';
+            }
+            {
+              id = "server-scalable";
+              config = ''
+                multiple clienst
+                see example file found in http://openvpn.net/index.php/documentation/howto.html
+              '';
+            }
+            {
+              id = "client-scalabe";
+              config = '' dito '';
+            }
+          ];
+          default = [];
+          description = ''
+            openvpn instances to be run. Each will be put into an extra job named openvpn-{id}
+
+            The up and down properties will be added config line up=/nix/store/xxx-up-script
+            automatically for you. If you define at least one of up/down
+            "script-security 2" will be prepended to your config.
+
+            Don't forget to check that the all package sizes can be sent. if scp hangs or such you should set
+            --fragment XXX --mssfix YYY.
+          '';
+        };
+      };
+    };
+  };
+
+###### implementation
+
+  cfg = config.services.openvpn;
+
+  inherit (pkgs) openvpn;
+  inherit (builtins) hasAttr;
+
+  PATH="${pkgs.iptables}/sbin:${pkgs.coreutils}/bin:${pkgs.iproute}/sbin:${pkgs.nettools}/sbin";
+
+  makeOpenVPNJob = cfg :
+    let
+      upScript = ''
+        #!/bin/sh
+        exec &> /var/log/openvpn-${cfg.id}-up
+        PATH=${PATH}
+        ${cfg.up}
+      '';
+      downScript = ''
+        #!/bin/sh
+        exec &> /var/log/openvpn-${cfg.id}-down
+        PATH=${PATH}
+        ${cfg.down}
+      '';
+      configFile = pkgs.writeText "openvpn-config-${cfg.id}" ''
+      ${if hasAttr "up" cfg || hasAttr "down" cfg then "script-security 2" else ""}
+      ${cfg.config}
+      ${if hasAttr "up" cfg then "up ${pkgs.writeScript "openvpn-${cfg.id}-up" upScript}" else "" }
+      ${if hasAttr "down" cfg then "down ${pkgs.writeScript "openvpn-${cfg.id}-down" downScript}" else "" }
+      '';
+    in {
+      name = "openvpn-${cfg.id}";
+
+      job = ''
+        description "OpenVPN-${cfg.id}"
+
+        start on network-interfaces/started
+        stop on network-interfaces/stop
+
+
+        PATH=${pkgs.coreutils}/bin
+
+        respawn
+        script
+          exec &> /var/log/openvpn-${cfg.id}
+          ${openvpn}/sbin/openvpn --config ${configFile}
+        end script
+      '';
+    };
+
+in
+
+
+mkIf cfg.enable {
+  require = [
+    options
+  ];
+
+  services = {
+    extraJobs = map makeOpenVPNJob cfg.servers;
+  };
+}