Give plugins more control of which configuration attributes to request, and pass received attributes back to the requesting handler

src/libstrongswan/attributes/attribute_handler.h

@@ -22,6 +22,7 @@
 #define ATTRIBUTE_HANDLER_H_
 
 #include <chunk.h>
+#include <utils/host.h>
 #include <utils/identification.h>
 
 #include "attributes.h"
@@ -56,6 +57,16 @@ struct attribute_handler_t {
 	 */
 	void (*release)(attribute_handler_t *this, identification_t *server,
 					configuration_attribute_type_t type, chunk_t data);
+
+	/**
+	 * Enumerate attributes to request from a server.
+	 *
+	 * @param server		server identity to request attributes from
+	 * @param vip			virtual IP we are requesting, if any
+	 * @return				enumerator (configuration_attribute_type_t, chunk_t)
+	 */
+	enumerator_t* (*create_attribute_enumerator)(attribute_handler_t *this,
+										identification_t *server, host_t *vip);
 };
 
 #endif /** ATTRIBUTE_HANDLER_H_ @}*/