/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/**
 * \file ssl_cache.h
 *
 * \brief SSL session cache implementation
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
#ifndef MBEDTLS_SSL_CACHE_H
#define MBEDTLS_SSL_CACHE_H

#include "ssl.h"

#if defined(MBEDTLS_THREADING_C)
#include "threading.h"
#endif

/**
 * \name SECTION: Module settings
 *
 * The configuration options you can set for this module are in this section.
 * Either change them in config.h or define them on the compiler command line.
 * \{
 */

#if !defined(MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT)
#define MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT       86400	/*!< 1 day  */
#endif

#if !defined(MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES)
#define MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES      50	/*!< Maximum entries in cache */
#endif

/* \} name SECTION: Module settings */

#ifdef __cplusplus
extern "C" {
#endif

typedef struct mbedtls_ssl_cache_context mbedtls_ssl_cache_context;
typedef struct mbedtls_ssl_cache_entry mbedtls_ssl_cache_entry;

/**
 * \brief   This structure is used for storing cache entries
 */
struct mbedtls_ssl_cache_entry {
#if defined(MBEDTLS_HAVE_TIME)
	mbedtls_time_t timestamp;	/*!< entry timestamp    */
#endif
	mbedtls_ssl_session session;	/*!< entry session      */
#if defined(MBEDTLS_X509_CRT_PARSE_C)
	mbedtls_x509_buf peer_cert;	/*!< entry peer_cert    */
#endif
	mbedtls_ssl_cache_entry *next;	/*!< chain pointer      */
};

/**
 * \brief Cache context
 */
struct mbedtls_ssl_cache_context {
	mbedtls_ssl_cache_entry *chain;	/*!< start of the chain     */
	int timeout;			/*!< cache entry timeout    */
	int max_entries;		/*!< maximum entries        */
#if defined(MBEDTLS_THREADING_C)
	mbedtls_threading_mutex_t mutex;	/*!< mutex                  */
#endif
};

/**
 * \brief          Initialize an SSL cache context
 *
 * \param cache    SSL cache context
 */
void mbedtls_ssl_cache_init(mbedtls_ssl_cache_context *cache);

/**
 * \brief          Cache get callback implementation
 *                 (Thread-safe if MBEDTLS_THREADING_C is enabled)
 *
 * \param data     SSL cache context
 * \param session  session to retrieve entry for
 */
int mbedtls_ssl_cache_get(void *data, mbedtls_ssl_session *session);

/**
 * \brief          Cache set callback implementation
 *                 (Thread-safe if MBEDTLS_THREADING_C is enabled)
 *
 * \param data     SSL cache context
 * \param session  session to store entry for
 */
int mbedtls_ssl_cache_set(void *data, const mbedtls_ssl_session *session);

#if defined(MBEDTLS_HAVE_TIME)
/**
 * \brief          Set the cache timeout
 *                 (Default: MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT (1 day))
 *
 *                 A timeout of 0 indicates no timeout.
 *
 * \param cache    SSL cache context
 * \param timeout  cache entry timeout in seconds
 */
void mbedtls_ssl_cache_set_timeout(mbedtls_ssl_cache_context *cache, int timeout);
#endif							/* MBEDTLS_HAVE_TIME */

/**
 * \brief          Set the maximum number of cache entries
 *                 (Default: MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES (50))
 *
 * \param cache    SSL cache context
 * \param max      cache entry maximum
 */
void mbedtls_ssl_cache_set_max_entries(mbedtls_ssl_cache_context *cache, int max);

/**
 * \brief          Free referenced items in a cache context and clear memory
 *
 * \param cache    SSL cache context
 */
void mbedtls_ssl_cache_free(mbedtls_ssl_cache_context *cache);

#ifdef __cplusplus
}
#endif
#endif							/* ssl_cache.h */
