implemented XCBC algorithms (signer, prf) for IKE on top of a crypter

supporting ike=...-aesxcbc-... in ipsec.conf 
added AUTH_AES_XCBC_96 and PRF_AES128_CBC to default IKE proposal
AES XCBC testcase

src/libstrongswan/plugins/xcbc/xcbc_plugin.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+/**
+ * @defgroup xcbc_p xcbc
+ * @ingroup plugins
+ *
+ * @defgroup xcbc_plugin xcbc_plugin
+ * @{ @ingroup xcbc_p
+ */
+
+#ifndef XCBC_PLUGIN_H_
+#define XCBC_PLUGIN_H_
+
+#include <plugins/plugin.h>
+
+typedef struct xcbc_plugin_t xcbc_plugin_t;
+
+/**
+ * Plugin implementing xcbc algorithm to provide crypter based PRF and signers.
+ */
+struct xcbc_plugin_t {
+
+	/**
+	 * implements plugin interface
+	 */
+	plugin_t plugin;
+};
+
+/**
+ * Create a xcbc_plugin instance.
+ */
+plugin_t *plugin_create();
+
+#endif /* XCBC_PLUGIN_H_ @}*/