/**
 * @file proposal_substructure.h
 * 
 * @brief Declaration of the class proposal_substructure_t. 
 * 
 * An object of this type represents an IKEv2 PROPOSAL Substructure and contains transforms.
 * 
 */

/*
 * 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.
 */
 
 /* offsetof macro */
#include <stddef.h>

#include "proposal_substructure.h"

#include <payloads/encodings.h>
#include <payloads/transform_substructure.h>
#include <types.h>
#include <utils/allocator.h>
#include <utils/linked_list.h>

/**
 * Private data of an proposal_substructure_t' Object
 * 
 */
typedef struct private_proposal_substructure_s private_proposal_substructure_t;

struct private_proposal_substructure_s {
	/**
	 * public proposal_substructure_t interface
	 */
	proposal_substructure_t public;
	
	/**
	 * next payload type
	 */
	u_int8_t  next_payload;

	
	/**
	 * Length of this payload
	 */
	u_int16_t proposal_length;
	
	
	/**
	 * Proposal number
	 */
	u_int8_t	 proposal_number;
	
	/**
	 * Protocol ID
	 */
	u_int8_t protocol_id;

	/**
	 * SPI size of the following SPI
	 */
 	u_int8_t  spi_size;

	/**
	 * Number of transforms
	 */
 	u_int8_t  transforms_count;
 	
 	/**
 	 * SPI is stored as chunk
 	 */
 	chunk_t spi;
 	
 	/**
 	 * Transforms are stored in a linked_list_t
 	 */
	linked_list_t * transforms;
	
	/**
	 * @brief Computes the length of this substructure.
	 *
	 * @param this 	calling private_proposal_substructure_t object
	 * @return 		
	 * 				SUCCESS in any case
	 */
	status_t (*compute_length) (private_proposal_substructure_t *this);
};

/**
 * Encoding rules to parse or generate a Proposal substructure
 * 
 * The defined offsets are the positions in a object of type 
 * private_proposal_substructure_t.
 * 
 */
encoding_rule_t proposal_substructure_encodings[] = {
 	/* 1 Byte next payload type, stored in the field next_payload */
	{ U_INT_8,			offsetof(private_proposal_substructure_t, next_payload) 			},
	/* Reserved Byte is skipped */
	{ RESERVED_BYTE,		0																},	
	/* Length of the whole proposal substructure payload*/
	{ PAYLOAD_LENGTH,		offsetof(private_proposal_substructure_t, proposal_length) 	},	
	/* proposal number is a number of 8 bit */
	{ U_INT_8,				offsetof(private_proposal_substructure_t, proposal_number) 	},	
	/* protocol ID is a number of 8 bit */
	{ U_INT_8,				offsetof(private_proposal_substructure_t, protocol_id)		},	
	/* SPI Size has its own type */
	{ SPI_SIZE,				offsetof(private_proposal_substructure_t, spi_size)			},	
	/* Number of transforms is a number of 8 bit */
	{ U_INT_8,				offsetof(private_proposal_substructure_t, transforms_count)	},	
	/* SPI is a chunk of variable size*/
	{ SPI,					offsetof(private_proposal_substructure_t, spi)				},	
	/* Transforms are stored in a transform substructure, 
	   offset points to a linked_list_t pointer */
	{ TRANSFORMS,				offsetof(private_proposal_substructure_t, transforms) 	}
};

/*
                           1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ! 0 (last) or 2 !   RESERVED    !         Proposal Length       !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ! Proposal #    !  Protocol ID  !    SPI Size   !# of Transforms!
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                        SPI (variable)                         ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                                                               !
      ~                        <Transforms>                           ~
      !                                                               !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/

/**
 * Implements payload_t's verify function.
 * See #payload_s.verify for description.
 */
static status_t verify(private_proposal_substructure_t *this)
{
	if ((this->next_payload != NO_PAYLOAD) && (this->next_payload != PROPOSAL_SUBSTRUCTURE))
	{
		/* must be 0 or 2 */
		return FAILED;
	}
	if (this->transforms_count != this->transforms->get_count(this->transforms))
	{
		/* must be the same! */
		return FAILED;
	}

	if (this->protocol_id > 4)
	{
		/* reserved are not supported */
		return FAILED;
	}

	/* proposal number is checked in SA payload */	
	return SUCCESS;
}

/**
 * Implements payload_t's get_encoding_rules function.
 * See #payload_s.get_encoding_rules for description.
 */
static status_t get_encoding_rules(private_proposal_substructure_t *this, encoding_rule_t **rules, size_t *rule_count)
{
	*rules = proposal_substructure_encodings;
	*rule_count = sizeof(proposal_substructure_encodings) / sizeof(encoding_rule_t);
	
	return SUCCESS;
}

/**
 * Implements payload_t's get_type function.
 * See #payload_s.get_type for description.
 */
static payload_type_t get_type(private_proposal_substructure_t *this)
{
	return PROPOSAL_SUBSTRUCTURE;
}

/**
 * Implements payload_t's get_next_type function.
 * See #payload_s.get_next_type for description.
 */
static payload_type_t get_next_type(private_proposal_substructure_t *this)
{
	return (this->next_payload);
}

/**
 * Implements payload_t's set_next_type function.
 * See #payload_s.set_next_type for description.
 */
static status_t set_next_type(private_proposal_substructure_t *this,payload_type_t type)
{
	return SUCCESS;
}

/**
 * Implements payload_t's get_length function.
 * See #payload_s.get_length for description.
 */
static size_t get_length(private_proposal_substructure_t *this)
{
	return this->proposal_length;
}

/**
 * Implements proposal_substructure_t's create_transform_substructure_iterator function.
 * See #proposal_substructure_s.create_transform_substructure_iterator for description.
 */
static status_t create_transform_substructure_iterator (private_proposal_substructure_t *this,linked_list_iterator_t **iterator,bool forward)
{
	return (this->transforms->create_iterator(this->transforms,iterator,forward));
}

/**
 * Implements proposal_substructure_t's add_transform_substructure function.
 * See #proposal_substructure_s.add_transform_substructure for description.
 */
static status_t add_transform_substructure (private_proposal_substructure_t *this,transform_substructure_t *transform)
{
	status_t status;
	if (this->transforms->get_count(this->transforms) > 0)
	{
		transform_substructure_t *last_transform;
		status = this->transforms->get_last(this->transforms,(void **) &last_transform);
		/* last transform is now not anymore last one */
		last_transform->set_is_last_transform(last_transform,FALSE);

	}
	transform->set_is_last_transform(transform,TRUE);
	
	status = this->transforms->insert_last(this->transforms,(void *) transform);
	this->compute_length(this);
	return status;
}

/**
 * Implements proposal_substructure_t's set_proposal_number function.
 * See #proposal_substructure_s.set_proposal_number for description.
 */
static status_t set_proposal_number(private_proposal_substructure_t *this,u_int8_t proposal_number)
{
	this->proposal_number = proposal_number;
	return SUCCESS;
}

/**
 * Implements proposal_substructure_t's get_proposal_number function.
 * See #proposal_substructure_s.get_proposal_number for description.
 */
static u_int8_t get_proposal_number (private_proposal_substructure_t *this)
{
	return (this->proposal_number);
}

/**
 * Implements proposal_substructure_t's set_protocol_id function.
 * See #proposal_substructure_s.set_protocol_id for description.
 */
static status_t set_protocol_id(private_proposal_substructure_t *this,u_int8_t protocol_id)
{
	this->protocol_id = protocol_id;
	return SUCCESS;
}

/**
 * Implements proposal_substructure_t's get_protocol_id function.
 * See #proposal_substructure_s.get_protocol_id for description.
 */
static u_int8_t get_protocol_id (private_proposal_substructure_t *this)
{
	return (this->protocol_id);
}


/**
 * Implements proposal_substructure_t's set_spi function.
 * See #proposal_substructure_s.set_spi for description.
 */
static status_t set_spi (private_proposal_substructure_t *this, chunk_t spi)
{
	/* first delete already set spi value */
	if (this->spi.ptr != NULL)
	{
		allocator_free(this->spi.ptr);
		this->spi.ptr = NULL;
		this->spi.len = 0;
		this->compute_length(this);
	}
	
	this->spi.ptr = allocator_clone_bytes(spi.ptr,spi.len);
	if (this->spi.ptr == NULL)
	{
		return OUT_OF_RES;
	}
	this->spi.len = spi.len;
	this->spi_size = spi.len;
	this->compute_length(this);

	return SUCCESS;
}

/**
 * Implements proposal_substructure_t's get_spi function.
 * See #proposal_substructure_s.get_spi for description.
 */
static chunk_t get_spi (private_proposal_substructure_t *this)
{
	chunk_t spi;
	spi.ptr = this->spi.ptr;
	spi.len = this->spi.len;		
	
	return spi;
}

/**
 * Implements private_proposal_substructure_t's compute_length function.
 * See #private_proposal_substructure_s.compute_length for description.
 */
static status_t compute_length (private_proposal_substructure_t *this)
{
	linked_list_iterator_t *iterator;
	status_t status;
	size_t transforms_count = 0;
	size_t length = PROPOSAL_SUBSTRUCTURE_HEADER_LENGTH;
	status = this->transforms->create_iterator(this->transforms,&iterator,TRUE);
	if (status != SUCCESS)
	{
		return length;
	}
	while (iterator->has_next(iterator))
	{
		payload_t * current_transform;
		iterator->current(iterator,(void **) &current_transform);
		length += current_transform->get_length(current_transform);
		transforms_count++;
	}
	iterator->destroy(iterator);
	
	length += this->spi.len;
	this->transforms_count= transforms_count;
	this->proposal_length = length;	

	return SUCCESS;
}

/**
 * Implements proposal_substructure_t's clone function.
 * See #proposal_substructure_s.clone for description.
 */
static status_t clone(private_proposal_substructure_t *this, private_proposal_substructure_t **clone)
{
	private_proposal_substructure_t * new_clone;
	linked_list_iterator_t *transforms;
	status_t status;
	
	new_clone = (private_proposal_substructure_t *) proposal_substructure_create();
	
	new_clone->next_payload = this->next_payload;
	new_clone->proposal_number = this->proposal_number;
	new_clone->protocol_id = this->protocol_id;
	new_clone->spi_size = this->spi_size;
	if (this->spi.ptr != NULL)
	{
		new_clone->spi.ptr = allocator_clone_bytes(this->spi.ptr,this->spi.len);
		if (new_clone->spi.ptr == NULL)
		{
			new_clone->public.destroy(&(new_clone->public));
			return OUT_OF_RES;
		}
		new_clone->spi.len = this->spi.len;
	}

	status = this->transforms->create_iterator(this->transforms,&transforms,FALSE);
	if (status != SUCCESS)
	{
		new_clone->public.destroy(&(new_clone->public));
		return status;
	}

	while (transforms->has_next(transforms))
	{
		transform_substructure_t *current_transform;
		transform_substructure_t *current_transform_clone;
		status = transforms->current(transforms,(void **) &current_transform);
		if (status != SUCCESS)
		{
			transforms->destroy(transforms);
			new_clone->public.destroy(&(new_clone->public));
			return status;
		}
		status = current_transform->clone(current_transform,&current_transform_clone);
		if (status != SUCCESS)
		{
			transforms->destroy(transforms);
			new_clone->public.destroy(&(new_clone->public));
			return status;
		}
		
		status = new_clone->public.add_transform_substructure(&(new_clone->public),current_transform_clone);
		if (status != SUCCESS)
		{
			transforms->destroy(transforms);
			current_transform_clone->destroy(current_transform_clone);
			new_clone->public.destroy(&(new_clone->public));
			return status;
		}				
	}
	
	transforms->destroy(transforms);	
	
	*clone = new_clone;	
	
	return SUCCESS;
}

/**
 * Implements payload_t's and proposal_substructure_t's destroy function.
 * See #payload_s.destroy or proposal_substructure_s.destroy for description.
 */
static status_t destroy(private_proposal_substructure_t *this)
{
	/* all proposals are getting destroyed */ 
	while (this->transforms->get_count(this->transforms) > 0)
	{
		transform_substructure_t *current_transform;
		if (this->transforms->remove_last(this->transforms,(void **)&current_transform) != SUCCESS)
		{
			break;
		}
		current_transform->destroy(current_transform);
	}
	this->transforms->destroy(this->transforms);
	
	if (this->spi.ptr != NULL)
	{
		allocator_free(this->spi.ptr);
	}
	
	allocator_free(this);
	
	return SUCCESS;
}

/*
 * Described in header
 */
proposal_substructure_t *proposal_substructure_create()
{
	private_proposal_substructure_t *this = allocator_alloc_thing(private_proposal_substructure_t);
	if (this == NULL)
	{
		return NULL;	
	}	

	/* interface functions */	
	this->public.payload_interface.verify = (status_t (*) (payload_t *))verify;
	this->public.payload_interface.get_encoding_rules = (status_t (*) (payload_t *, encoding_rule_t **, size_t *) ) get_encoding_rules;
	this->public.payload_interface.get_length = (size_t (*) (payload_t *)) get_length;
	this->public.payload_interface.get_next_type = (payload_type_t (*) (payload_t *)) get_next_type;
	this->public.payload_interface.set_next_type = (status_t (*) (payload_t *,payload_type_t)) set_next_type;	
	this->public.payload_interface.get_type = (payload_type_t (*) (payload_t *)) get_type;
	this->public.payload_interface.destroy = (status_t (*) (payload_t *))destroy;
	
	/* public functions */
	this->public.create_transform_substructure_iterator = (status_t (*) (proposal_substructure_t *,linked_list_iterator_t **,bool)) create_transform_substructure_iterator;
	this->public.add_transform_substructure = (status_t (*) (proposal_substructure_t *,transform_substructure_t *)) add_transform_substructure;
	this->public.set_proposal_number = (status_t (*) (proposal_substructure_t *,u_int8_t))set_proposal_number;
	this->public.get_proposal_number = (u_int8_t (*) (proposal_substructure_t *)) get_proposal_number;
	this->public.set_protocol_id = (status_t (*) (proposal_substructure_t *,u_int8_t))set_protocol_id;
	this->public.get_protocol_id = (u_int8_t (*) (proposal_substructure_t *)) get_protocol_id;
	this->public.set_spi = (status_t (*) (proposal_substructure_t *,chunk_t))set_spi;
	this->public.get_spi = (chunk_t (*) (proposal_substructure_t *)) get_spi;
	this->public.clone = (status_t (*) (proposal_substructure_t *, proposal_substructure_t **)) clone;
	this->public.destroy = (status_t (*) (proposal_substructure_t *)) destroy;
	
	/* private functions */
	this->compute_length = compute_length;
	
	/* set default values of the fields */
	this->next_payload = NO_PAYLOAD;
	this->proposal_length = 0;
	this->proposal_number = 0;
	this->protocol_id = 0;
	this->transforms_count = 0;
	this->spi_size = 0;
	this->spi.ptr = NULL;
	this->spi.len = 0;

	this->transforms = linked_list_create();
	
	if (this->transforms == NULL)
	{
		allocator_free(this);
		return NULL;
	}
	return (&(this->public));
}