/*
 * Copyright (C) 2011 Andreas Steffen
 * HSR 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 "tnccs_dynamic.h"

#include <tnc/tnc.h>

#include <debug.h>

typedef struct private_tnccs_dynamic_t private_tnccs_dynamic_t;

/**
 * Private data of a tnccs_dynamic_t object.
 */
struct private_tnccs_dynamic_t {

	/**
	 * Public tls_t interface.
	 */
	tls_t public;

	/**
	 * Detected TNC IF-TNCCS stack
	 */
	tls_t *tls;
};

/**
 * Determine the version of the IF-TNCCS protocol used by analyzing the first
 * byte of the TNCCS batch received from a TNC Client according to the rules
 * defined by section 3.5 "Interoperability with older IF-TNCCS versions" of
 * the TCG TNC IF-TNCCS TLV Bindings Version 2.0 standard.
 */
tnccs_type_t determine_tnccs_protocol(char version)
{
	switch (version)
	{
		case '\t':
		case '\n':
		case '\r':
		case ' ':
		case '<':
			return TNCCS_1_1;
		case 0x00:
			return TNCCS_SOH;
		case 0x02:
			return TNCCS_2_0;
		default:
			return TNCCS_UNKNOWN;
	}
}

METHOD(tls_t, process, status_t,
	private_tnccs_dynamic_t *this, void *buf, size_t buflen)
{
	tnccs_type_t type;

	if (!this->tls)
	{
		if (buflen == 0)
		{
			return FAILED;
		}
		type = determine_tnccs_protocol(*(char*)buf);
		DBG1(DBG_TNC, "%N protocol detected dynamically",
					   tnccs_type_names, type);
		this->tls = (tls_t*)tnc->tnccs->create_instance(tnc->tnccs, type, TRUE);
		if (!this->tls)
		{
			DBG1(DBG_TNC, "N% protocol not supported", tnccs_type_names, type);
			return FAILED;
		}
	}
	return this->tls->process(this->tls, buf, buflen);
}

METHOD(tls_t, build, status_t,
	private_tnccs_dynamic_t *this, void *buf, size_t *buflen, size_t *msglen)
{
	return this->tls->build(this->tls, buf, buflen, msglen);
}

METHOD(tls_t, is_server, bool,
	private_tnccs_dynamic_t *this)
{
	return TRUE;
}

METHOD(tls_t, get_purpose, tls_purpose_t,
	private_tnccs_dynamic_t *this)
{
	return TLS_PURPOSE_EAP_TNC;
}

METHOD(tls_t, is_complete, bool,
	private_tnccs_dynamic_t *this)
{
	return this->tls ? this->tls->is_complete(this->tls) : FALSE;
}

METHOD(tls_t, get_eap_msk, chunk_t,
	private_tnccs_dynamic_t *this)
{
	return chunk_empty;
}

METHOD(tls_t, destroy, void,
	private_tnccs_dynamic_t *this)
{
	DESTROY_IF(this->tls);
	free(this);	
}

/**
 * See header
 */
tls_t *tnccs_dynamic_create(bool is_server)
{
	private_tnccs_dynamic_t *this;

	INIT(this,
		.public = {
			.process = _process,
			.build = _build,
			.is_server = _is_server,
			.get_purpose = _get_purpose,
			.is_complete = _is_complete,
			.get_eap_msk = _get_eap_msk,
			.destroy = _destroy,
		},
	);

	return &this->public;
}