/**
 * @file transform_substructure.h
 * 
 * @brief Interface of transform_substructure_t.
 * 
 */

/*
 * Copyright (C) 2005 Jan Hutter, 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.
 */

#ifndef TRANSFORM_SUBSTRUCTURE_H_
#define TRANSFORM_SUBSTRUCTURE_H_

#include <types.h>
#include <definitions.h>
#include <encoding/payloads/payload.h>
#include <encoding/payloads/transform_attribute.h>
#include <utils/linked_list.h>
#include <transforms/diffie_hellman.h>
#include <transforms/signers/signer.h>
#include <transforms/prfs/prf.h>
#include <transforms/crypters/crypter.h>


/**
 * IKEv1 Value for a transform payload.
 * 
 * @ingroup payloads
 */
#define TRANSFORM_TYPE_VALUE 3

/**
 * Length of the transform substructure header in bytes.
 * 
 * @ingroup payloads
 */
#define TRANSFORM_SUBSTRUCTURE_HEADER_LENGTH 8


typedef enum transform_type_t transform_type_t;

/**
 * Type of a transform, as in IKEv2 draft 3.3.2.
 * 
 * @ingroup payloads
 */
enum transform_type_t {
	UNDEFINED_TRANSFORM_TYPE = 241,
	ENCRYPTION_ALGORITHM = 1,
	PSEUDO_RANDOM_FUNCTION = 2,
	INTEGRITY_ALGORITHM = 3,
	DIFFIE_HELLMAN_GROUP = 4,
	EXTENDED_SEQUENCE_NUMBERS = 5
};

/** 
 * String mappings for transform_type_t.
 * 
 * @ingroup payloads
 */
extern mapping_t transform_type_m[];


typedef enum extended_sequence_numbers_t extended_sequence_numbers_t;

/** 
 * Extended sequence numbers, as in IKEv2 draft 3.3.2.
 * 
 * @ingroup payloads
 */
enum extended_sequence_numbers_t {
	NO_EXT_SEQ_NUMBERS = 0,
	EXT_SEQ_NUMBERS = 1
};

/** 
 * String mappings for extended_sequence_numbers_t.
 * 
 * @ingroup payloads
 */
extern mapping_t extended_sequence_numbers_m[];

typedef struct transform_substructure_t transform_substructure_t;

/**
 * Object representing an IKEv2- TRANSFORM SUBSTRUCTURE.
 * 
 * The TRANSFORM SUBSTRUCTURE format is described in RFC section 3.3.2.
 * 
 * @ingroup payloads
 */
struct transform_substructure_t {
	/**
	 * The payload_t interface.
	 */
	payload_t payload_interface;
	
	/**
	 * @brief Creates an iterator of stored transform_attribute_t objects.
	 * 
	 * @warning The created iterator has to get destroyed by the caller!
	 * 
	 * @warning When deleting an transform attribute using this iterator, 
	 * 			the length of this transform substructure has to be refreshed 
	 * 			by calling get_length()!
	 *
	 * @param this 			calling transform_substructure_t object
	 * @param[in] forward 	iterator direction (TRUE: front to end)
	 * @return				created iterator_t object.
	 */
	iterator_t * (*create_transform_attribute_iterator) (transform_substructure_t *this, bool forward);
	
	/**
	 * @brief Adds a transform_attribute_t object to this object.
	 * 
	 * @warning The added proposal_substructure_t object  is 
	 * 			getting destroyed in destroy function of transform_substructure_t.
	 *
	 * @param this 		calling transform_substructure_t object
	 * @param proposal  transform_attribute_t object to add
	 */
	void (*add_transform_attribute) (transform_substructure_t *this,transform_attribute_t *attribute);
	
	/**
	 * @brief Sets the next_payload field of this substructure
	 * 
	 * If this is the last transform, next payload field is set to 0,
	 * otherwise to 3
	 *
	 * @param this 		calling transform_substructure_t object
	 * @param is_last	When TRUE, next payload field is set to 0, otherwise to 3
	 */
	void (*set_is_last_transform) (transform_substructure_t *this, bool is_last);
	
	/**
	 * @brief Checks if this is the last transform.
	 * 
	 * @param this 		calling transform_substructure_t object
	 * @return 			TRUE if this is the last Transform, FALSE otherwise
	 */
	bool (*get_is_last_transform) (transform_substructure_t *this);
	
	/**
	 * @brief Sets transform type of the current transform substructure.
	 *
	 * @param this 		calling transform_substructure_t object
	 * @param type		type value to set
	 */
	void (*set_transform_type) (transform_substructure_t *this,u_int8_t type);
	
	/**
	 * @brief get transform type of the current transform.
	 * 
	 * @param this 		calling transform_substructure_t object
	 * @return 			Transform type of current transform substructure.
	 */
	u_int8_t (*get_transform_type) (transform_substructure_t *this);
	
	/**
	 * @brief Sets transform id of the current transform substructure.
	 *
	 * @param this 		calling transform_substructure_t object
	 * @param id			transform id to set
	 */
	void (*set_transform_id) (transform_substructure_t *this,u_int16_t id);
	
	/**
	 * @brief get transform id of the current transform.
	 * 
	 * @param this 		calling transform_substructure_t object
	 * @return 			Transform id of current transform substructure.
	 */
	u_int16_t (*get_transform_id) (transform_substructure_t *this);
	
	/**
	 * @brief get transform id of the current transform.
	 * 
	 * @param this 			calling transform_substructure_t object
	 * @param key_length		The key length is written to this location	
	 * @return 			
	 * 						- SUCCESS if a key length attribute is contained
	 * 						- FAILED if no key length attribute is part of this 
	 * 						  transform or key length uses more then 16 bit!
	 */
	status_t (*get_key_length) (transform_substructure_t *this,u_int16_t *key_length);

	/**
	 * @brief Clones an transform_substructure_t object.
	 *
	 * @param this 	transform_substructure_t object to clone
	 * @return		cloned transform_substructure_t object
	 */
	transform_substructure_t* (*clone) (transform_substructure_t *this);

	/**
	 * @brief Destroys an transform_substructure_t object.
	 *
	 * @param this 	transform_substructure_t object to destroy
	 */
	void (*destroy) (transform_substructure_t *this);
};

/**
 * @brief Creates an empty transform_substructure_t object.
 * 
 * @return			created transform_substructure_t object
 * 
 * @ingroup payloads
 */
transform_substructure_t *transform_substructure_create();

/**
 * @brief Creates an empty transform_substructure_t object.
 * 
 * The key length is used for the transport types ENCRYPTION_ALGORITHM,
 * PSEUDO_RANDOM_FUNCTION, INTEGRITY_ALGORITHM. For all 
 * other transport types the key_length parameter is not used
 * 
 * @return					created transform_substructure_t object
 * @param transform_type	type of transform to create
 * @param transform_id		transform id specifying the specific algorithm of a transform type
 * @param key_length		Key length for key lenght attribute
 * 
 * @ingroup payloads
 */
transform_substructure_t *transform_substructure_create_type(transform_type_t transform_type, u_int16_t transform_id, u_int16_t key_length);

#endif /*TRANSFORM_SUBSTRUCTURE_H_*/