/**
 * @file configuration.c
 * 
 * @brief Configuration class used to store IKE_SA-configurations.
 * 
 * Object of this type represents the configuration for all IKE_SA's and their child_sa's.
 * 
 */

/*
 * 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.
 */

#include <stdlib.h>

#include "configuration_manager.h"

#include <types.h>
#include <globals.h>
#include <utils/allocator.h>
#include <encoding/payloads/nonce_payload.h>
#include <encoding/payloads/proposal_substructure.h>
#include <encoding/payloads/ke_payload.h>
#include <encoding/payloads/transform_attribute.h>

typedef struct private_configuration_manager_t private_configuration_manager_t;

/**
 * Private data of an configuration_t object
 */
struct private_configuration_manager_t {

	/**
	 * Public part
	 */
	configuration_manager_t public;

	/**
	 * Assigned logger object 
	 */
	logger_t *logger;
};

/**
 * Implements function configuration_manager_t.get_remote_host.
 */
static status_t get_remote_host(private_configuration_manager_t *this, char *name, host_t **host)
{
	/*
	 * For testing purposes, hard coded host informations for two configurations are returned.
	 * 
	 * Further improvements could store them in a linked list or hash table.
	 */

	host_t *remote;
	status_t status = SUCCESS;
	
	if (strcmp(name, "pinflb30") == 0)
	{
		remote = host_create(AF_INET, "152.96.193.130", 500);
	}
	else if (strcmp(name, "pinflb31") == 0)
	{
		remote = host_create(AF_INET, "152.96.193.131", 500);
	}
	else if (strcmp(name, "localhost") == 0)
	{
		remote = host_create(AF_INET, "127.0.0.1", 500);
	}
	else
	{
		status = NOT_FOUND;
	}
	if ((status != NOT_FOUND) && (remote == NULL))
	{
		return OUT_OF_RES;	
	}

	*host = remote;
	return status;
}

/**
 * Implements function configuration_manager_t.get_local_host.
 */
static status_t get_local_host(private_configuration_manager_t *this, char *name, host_t **host)
{
	/*
	 * For testing purposes, only the default route is returned for each configuration.
	 * 
	 * Further improvements could store different local host informations in a linked list or hash table.
	 */
	host_t *local;
	local = host_create(AF_INET, "0.0.0.0", 0);
	if (local == NULL)
	{
		return OUT_OF_RES;	
	}
	*host = local;
	return SUCCESS;
}

/**
 * Implements function configuration_manager_t.get_dh_group_number.
 */
static status_t get_dh_group_number(private_configuration_manager_t *this,char *name, u_int16_t *dh_group_number, u_int16_t priority)
{
	/* Currently only two dh_group_numbers are supported for each configuration*/
	
	if (priority == 1)
	{
		*dh_group_number = MODP_1024_BIT;
	}
	else
	{
		*dh_group_number = MODP_768_BIT;
	}
	return SUCCESS;
}

/**
 * Implements function configuration_manager_t.get_proposals_for_host.
 */
static status_t get_proposals_for_host(private_configuration_manager_t *this, host_t *host, iterator_t *iterator)
{
	/* 
	 * Currently the following hard coded proposal is created and returned for all hosts:
	 * - ENCR_AES_CBC 128Bit
	 * - PRF_HMAC_MD5 128Bit
	 * - AUTH_HMAC_MD5_96 128Bit
	 * - MODP_1024_BIT
	 */
	proposal_substructure_t *proposal;
	transform_substructure_t *transform;
	transform_attribute_t *attribute;
	status_t status;
	
	proposal = proposal_substructure_create();
	if (proposal == NULL)
	{
		return OUT_OF_RES;
	}
	
	proposal->set_proposal_number(proposal, 1);
	proposal->set_protocol_id(proposal, 1);
	
	/* 
	 * Encryption Algorithm 
	 */
	transform = transform_substructure_create();
	if (transform == NULL)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	status = proposal->add_transform_substructure(proposal, transform);
	if (status != SUCCESS)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	transform->set_transform_type(transform, ENCRYPTION_ALGORITHM);
	transform->set_transform_id(transform, ENCR_AES_CBC);
	
	attribute = transform_attribute_create();
	if (attribute == NULL)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	status = transform->add_transform_attribute(transform, attribute);
	if (status != SUCCESS)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	attribute->set_attribute_type(attribute, KEY_LENGTH);
	attribute->set_value(attribute, 16);
	
 	/* 
 	 * Pseudo-random Function
 	 */
 	transform = transform_substructure_create();
	if (transform == NULL)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	status = proposal->add_transform_substructure(proposal, transform);
	if (status != SUCCESS)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	transform->set_transform_type(transform, PSEUDO_RANDOM_FUNCTION);
	transform->set_transform_id(transform, PRF_HMAC_MD5);
	
	attribute = transform_attribute_create();
	if (attribute == NULL)
	{		
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	status = transform->add_transform_attribute(transform, attribute);
	if (status != SUCCESS)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	attribute->set_attribute_type(attribute, KEY_LENGTH);
	attribute->set_value(attribute, 16);

 	
 	/* 
 	 * Integrity Algorithm 
 	 */
 	transform = transform_substructure_create();
	if (transform == NULL)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	status = proposal->add_transform_substructure(proposal, transform);
	if (status != SUCCESS)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	transform->set_transform_type(transform, INTEGRITIY_ALGORITHM);
	transform->set_transform_id(transform, AUTH_HMAC_MD5_96);
	
	attribute = transform_attribute_create();
	if (attribute == NULL)
	{		
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	status = transform->add_transform_attribute(transform, attribute);
	if (status != SUCCESS)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	attribute->set_attribute_type(attribute, KEY_LENGTH);
	attribute->set_value(attribute, 16);
 	
 	
    /* 
     * Diffie-Hellman Group 
     */
 	transform = transform_substructure_create();
	if (transform == NULL)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	status = proposal->add_transform_substructure(proposal, transform);
	if (status != SUCCESS)
	{
		proposal->destroy(proposal);
		return OUT_OF_RES;
	}
	transform->set_transform_type(transform, DIFFIE_HELLMAN_GROUP);
	transform->set_transform_id(transform, MODP_1024_BIT);
	
	iterator->insert_after(iterator, (void*)proposal);
	
	return SUCCESS;
}
	
/**
 * Implements function configuration_manager_t.select_proposals_for_host.
 */
static status_t select_proposals_for_host(private_configuration_manager_t *this, host_t *host, iterator_t *in, iterator_t *out)
{
	/* Currently the first suggested proposal is selected, cloned and then returned*/
	status_t status;
	proposal_substructure_t *first_suggested_proposal;
	proposal_substructure_t *selected_proposal;
	
	this->logger->log(this->logger,CONTROL | MORE, "Going to select first suggested proposal");
	if (!in->has_next(in))
	{
		this->logger->log(this->logger,ERROR | MORE, "No proposal suggested");
		/* no suggested proposal! */
		return FAILED;
	}
	
	status = in->current(in,(void **) &first_suggested_proposal);
	if (status != SUCCESS)
	{
		this->logger->log(this->logger,ERROR, "Fatal error: could not get first proposal from iterator");
		return status;	
	}
	status = first_suggested_proposal->clone(first_suggested_proposal,&selected_proposal);
	if (status != SUCCESS)
	{
		this->logger->log(this->logger,ERROR, "Fatal error: could not clone proposal");
		/* could not clone proposal */
		return status;	
	}
	
	status = out->insert_after(out,selected_proposal);
	if (status != SUCCESS)
	{
		this->logger->log(this->logger,ERROR, "Fatal error: could not insert selected proposal in out iterator");
	}	
	return status;
}

/**
 * Implements function configuration_manager_t.get_transforms_for_host_and_proposals.
 */
static status_t get_transforms_for_host_and_proposals (private_configuration_manager_t *this, host_t *host, iterator_t *proposals,encryption_algorithm_t *encryption_algorithm,pseudo_random_function_t *pseudo_random_function, integrity_algorithm_t *integrity_algorithm)
{
	/*
	 * Currently the given proposals are not checked if they are valid for specific host!
	 * 
	 * The first proposal is taken and the appropriate transform objects are created (only if they are supported)
	 */

	encryption_algorithm_t		selected_encryption_algorithm = ENCR_UNDEFINED;
	pseudo_random_function_t		selected_pseudo_random_function = PRF_UNDEFINED;
	integrity_algorithm_t		selected_integrity_algorithm = AUTH_UNDEFINED;
	proposal_substructure_t *proposal;
	iterator_t *transforms;
	status_t status;

	this->logger->log(this->logger,ERROR, "Going to get transforms for given proposal");

	if (!proposals->has_next(proposals))
	{
		this->logger->log(this->logger,ERROR | MORE, "No proposal available");
		return FAILED;
	}
	
	status = proposals->current(proposals,(void **) &(proposal));
	if (status != SUCCESS)
	{
		this->logger->log(this->logger,ERROR, "Fatal error: could not get first proposal from iterator");
		return status;	
	}
	
	status = proposal->create_transform_substructure_iterator(proposal,&transforms,TRUE);
	if (status != SUCCESS)
	{
		this->logger->log(this->logger,ERROR, "Fatal error: could not create iterator of transforms");
		return status;	
	}
	
	while (transforms->has_next(transforms))
	{
		transform_substructure_t *current_transform;
		transform_type_t transform_type;
		u_int16_t transform_id;
		
		status = transforms->current(transforms,(void **) &(current_transform));
		if (status != SUCCESS)
		{
			this->logger->log(this->logger,ERROR, "Fatal error: could not get current transform substructure object");
			transforms->destroy(transforms);	
			return status;	
		}
		
		transform_type = current_transform->get_transform_type(current_transform);
		transform_id = current_transform->get_transform_id(current_transform);
		
		this->logger->log(this->logger,CONTROL | MOST, "Going to process transform of type %s",mapping_find(transform_type_m,transform_type));
		switch (transform_type)
		{
			case ENCRYPTION_ALGORITHM:
			{
				this->logger->log(this->logger,CONTROL | MORE, "Encryption algorithm: %s",mapping_find(encryption_algorithm_m,transform_id));	
				selected_encryption_algorithm = transform_id;
				break;
			}
			case	 PSEUDO_RANDOM_FUNCTION:
			{
				this->logger->log(this->logger,CONTROL | MORE, "Create transform object for PRF of type %s",mapping_find(pseudo_random_function_m,transform_id));
				selected_pseudo_random_function = transform_id;
				break;
			}
			case INTEGRITIY_ALGORITHM:
			{
				this->logger->log(this->logger,CONTROL | MORE, "Integrity algorithm: %s",mapping_find(integrity_algorithm_m,transform_id));
				selected_integrity_algorithm = transform_id;
				break;
			}
			case DIFFIE_HELLMAN_GROUP:
			{
				this->logger->log(this->logger,CONTROL | MORE, "DH Group: %s",mapping_find(diffie_hellman_group_m,transform_id));
				break;
			}
			default:
			{
				this->logger->log(this->logger,ERROR  | MORE, "Transform type not supported!");
				transforms->destroy(transforms);	
				return FAILED;
			}	
		}
	}
	
	transforms->destroy(transforms);

	*encryption_algorithm = selected_encryption_algorithm;
	*pseudo_random_function = selected_pseudo_random_function;
	*integrity_algorithm = selected_integrity_algorithm;
	return SUCCESS;
}

/**
 * Implements function configuration_manager_t.is_dh_group_allowed_for_host.
 */
static status_t is_dh_group_allowed_for_host(private_configuration_manager_t *this, host_t *host, diffie_hellman_group_t group, bool *allowed)
{
	/*
	 * Only the two DH groups 768 and 1024 are supported for each configuration
	 */
	
	if (group == MODP_768_BIT || group == MODP_1024_BIT)
	{
		*allowed = TRUE;		
	}
	*allowed = FALSE;
	
	this->logger->log(this->logger,CONTROL | MORE, "DH group %s is %s",mapping_find(diffie_hellman_group_m, group),(allowed)? "allowed" : "not allowed");
	return SUCCESS;
}


/**
 * Implements function destroy of configuration_t.
 * See #configuration_s.destroy for description.
 */
static status_t destroy(private_configuration_manager_t *this)
{
	this->logger->log(this->logger,CONTROL | MORE, "Going to destroy configuration manager ");
	
	this->logger->log(this->logger,CONTROL | MOST, "Destroy assigned logger");
	global_logger_manager->destroy_logger(global_logger_manager,this->logger);
	allocator_free(this);
	return SUCCESS;
}

/*
 * Described in header-file
 */
configuration_manager_t *configuration_manager_create()
{
	private_configuration_manager_t *this = allocator_alloc_thing(private_configuration_manager_t);
	
	if (this == NULL)
	{
		return NULL;
	}

	/* public functions */
	this->public.destroy = (status_t(*)(configuration_manager_t*))destroy;
	this->public.get_remote_host = (status_t(*)(configuration_manager_t*,char*,host_t**))get_remote_host;
	this->public.get_local_host = (status_t(*)(configuration_manager_t*,char*,host_t**))get_local_host;
	this->public.get_dh_group_number = (status_t(*)(configuration_manager_t*,char*,u_int16_t *, u_int16_t))get_dh_group_number;
	this->public.get_proposals_for_host = (status_t(*)(configuration_manager_t*,host_t*,iterator_t*))get_proposals_for_host;
	this->public.select_proposals_for_host = (status_t(*)(configuration_manager_t*,host_t*,iterator_t*,iterator_t*))select_proposals_for_host;
	this->public.get_transforms_for_host_and_proposals =  (status_t (*) (configuration_manager_t *, host_t *, iterator_t *,encryption_algorithm_t *,pseudo_random_function_t *, integrity_algorithm_t *)) get_transforms_for_host_and_proposals;
	this->public.is_dh_group_allowed_for_host = (status_t(*)(configuration_manager_t*,host_t*,diffie_hellman_group_t,bool*)) is_dh_group_allowed_for_host;

	/* private variables */
	this->logger = global_logger_manager->create_logger(global_logger_manager,CONFIGURATION_MANAGER,NULL);

	if (this->logger == NULL)
	{
		allocator_free(this);
		return NULL;
	}

	return (&this->public);
}