restructuring of configuration backends

added propotypes of new control interfaces (xml & dbus)
introduced loadable:
  configuration backends
  control interfaces
using pluggable modules as in EAP

src/charon/control/interfaces/xml_interface.c

@@ -0,0 +1,63 @@
+/**
+ * @file xml_interface.c
+ * 
+ * @brief Implementation of xml_interface_t.
+ * 
+ */
+
+/*
+ * Copyright (C) 2007 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <stdlib.h>
+
+#include "xml_interface.h"
+
+#include <library.h>
+#include <daemon.h>
+
+
+typedef struct private_xml_interface_t private_xml_interface_t;
+
+/**
+ * Private data of an xml_interface_t object.
+ */
+struct private_xml_interface_t {
+
+	/**
+	 * Public part of xml_t object.
+	 */
+	xml_interface_t public;
+};
+
+
+/**
+ * Implementation of itnerface_t.destroy.
+ */
+static void destroy(private_xml_interface_t *this)
+{
+	free(this);
+}
+
+/*
+ * Described in header file
+ */
+interface_t *interface_create()
+{
+	private_xml_interface_t *this = malloc_thing(private_xml_interface_t);
+
+	this->public.interface.destroy = (void (*)(xml_interface_t*))destroy;
+	
+	return &this->public;
+}