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/**
* \file ssl_ticket.h
*
* \brief TLS server ticket callbacks implementation
*/
/*
* Copyright The Mbed TLS Contributors
* 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.
*/
#ifndef MBEDTLS_SSL_TICKET_H
#define MBEDTLS_SSL_TICKET_H
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
/*
* This implementation of the session ticket callbacks includes key
* management, rotating the keys periodically in order to preserve forward
* secrecy, when MBEDTLS_HAVE_TIME is defined.
*/
#include "mbedtls/ssl.h"
#include "mbedtls/cipher.h"
#if defined(MBEDTLS_THREADING_C)
#include "mbedtls/threading.h"
#endif
#ifdef __cplusplus
extern "C" {
#endif
/**
* \brief Information for session ticket protection
*/
typedef struct mbedtls_ssl_ticket_key
{
unsigned char name[4]; /*!< random key identifier */
uint32_t generation_time; /*!< key generation timestamp (seconds) */
mbedtls_cipher_context_t ctx; /*!< context for auth enc/decryption */
}
mbedtls_ssl_ticket_key;
/**
* \brief Context for session ticket handling functions
*/
typedef struct mbedtls_ssl_ticket_context
{
mbedtls_ssl_ticket_key keys[2]; /*!< ticket protection keys */
unsigned char active; /*!< index of the currently active key */
uint32_t ticket_lifetime; /*!< lifetime of tickets in seconds */
/** Callback for getting (pseudo-)random numbers */
int (*f_rng)(void *, unsigned char *, size_t);
void *p_rng; /*!< context for the RNG function */
#if defined(MBEDTLS_THREADING_C)
mbedtls_threading_mutex_t mutex;
#endif
}
mbedtls_ssl_ticket_context;
/**
* \brief Initialize a ticket context.
* (Just make it ready for mbedtls_ssl_ticket_setup()
* or mbedtls_ssl_ticket_free().)
*
* \param ctx Context to be initialized
*/
void mbedtls_ssl_ticket_init( mbedtls_ssl_ticket_context *ctx );
/**
* \brief Prepare context to be actually used
*
* \param ctx Context to be set up
* \param f_rng RNG callback function
* \param p_rng RNG callback context
* \param cipher AEAD cipher to use for ticket protection.
* Recommended value: MBEDTLS_CIPHER_AES_256_GCM.
* \param lifetime Tickets lifetime in seconds
* Recommended value: 86400 (one day).
*
* \note It is highly recommended to select a cipher that is at
* least as strong as the strongest ciphersuite
* supported. Usually that means a 256-bit key.
*
* \note The lifetime of the keys is twice the lifetime of tickets.
* It is recommended to pick a reasonnable lifetime so as not
* to negate the benefits of forward secrecy.
*
* \return 0 if successful,
* or a specific MBEDTLS_ERR_XXX error code
*/
int mbedtls_ssl_ticket_setup( mbedtls_ssl_ticket_context *ctx,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
mbedtls_cipher_type_t cipher,
uint32_t lifetime );
/**
* \brief Implementation of the ticket write callback
*
* \note See \c mbedtls_ssl_ticket_write_t for description
*/
mbedtls_ssl_ticket_write_t mbedtls_ssl_ticket_write;
/**
* \brief Implementation of the ticket parse callback
*
* \note See \c mbedtls_ssl_ticket_parse_t for description
*/
mbedtls_ssl_ticket_parse_t mbedtls_ssl_ticket_parse;
/**
* \brief Free a context's content and zeroize it.
*
* \param ctx Context to be cleaned up
*/
void mbedtls_ssl_ticket_free( mbedtls_ssl_ticket_context *ctx );
#ifdef __cplusplus
}
#endif
#endif /* ssl_ticket.h */
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