4 * \brief TLS server ticket callbacks implementation
7 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
8 * SPDX-License-Identifier: Apache-2.0
10 * Licensed under the Apache License, Version 2.0 (the "License"); you may
11 * not use this file except in compliance with the License.
12 * You may obtain a copy of the License at
14 * http://www.apache.org/licenses/LICENSE-2.0
16 * Unless required by applicable law or agreed to in writing, software
17 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
18 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 * See the License for the specific language governing permissions and
20 * limitations under the License.
22 * This file is part of mbed TLS (https://tls.mbed.org)
24 #ifndef MBEDTLS_SSL_TICKET_H
25 #define MBEDTLS_SSL_TICKET_H
27 #if !defined(MBEDTLS_CONFIG_FILE)
30 #include MBEDTLS_CONFIG_FILE
34 * This implementation of the session ticket callbacks includes key
35 * management, rotating the keys periodically in order to preserve forward
36 * secrecy, when MBEDTLS_HAVE_TIME is defined.
42 #if defined(MBEDTLS_THREADING_C)
43 #include "threading.h"
51 * \brief Information for session ticket protection
53 typedef struct mbedtls_ssl_ticket_key
55 unsigned char name[4]; /*!< random key identifier */
56 uint32_t generation_time; /*!< key generation timestamp (seconds) */
57 mbedtls_cipher_context_t ctx; /*!< context for auth enc/decryption */
59 mbedtls_ssl_ticket_key;
62 * \brief Context for session ticket handling functions
64 typedef struct mbedtls_ssl_ticket_context
66 mbedtls_ssl_ticket_key keys[2]; /*!< ticket protection keys */
67 unsigned char active; /*!< index of the currently active key */
69 uint32_t ticket_lifetime; /*!< lifetime of tickets in seconds */
71 /** Callback for getting (pseudo-)random numbers */
72 int (*f_rng)(void *, unsigned char *, size_t);
73 void *p_rng; /*!< context for the RNG function */
75 #if defined(MBEDTLS_THREADING_C)
76 mbedtls_threading_mutex_t mutex;
79 mbedtls_ssl_ticket_context;
82 * \brief Initialize a ticket context.
83 * (Just make it ready for mbedtls_ssl_ticket_setup()
84 * or mbedtls_ssl_ticket_free().)
86 * \param ctx Context to be initialized
88 void mbedtls_ssl_ticket_init( mbedtls_ssl_ticket_context *ctx );
91 * \brief Prepare context to be actually used
93 * \param ctx Context to be set up
94 * \param f_rng RNG callback function
95 * \param p_rng RNG callback context
96 * \param cipher AEAD cipher to use for ticket protection.
97 * Recommended value: MBEDTLS_CIPHER_AES_256_GCM.
98 * \param lifetime Tickets lifetime in seconds
99 * Recommended value: 86400 (one day).
101 * \note It is highly recommended to select a cipher that is at
102 * least as strong as the the strongest ciphersuite
103 * supported. Usually that means a 256-bit key.
105 * \note The lifetime of the keys is twice the lifetime of tickets.
106 * It is recommended to pick a reasonnable lifetime so as not
107 * to negate the benefits of forward secrecy.
109 * \return 0 if successful,
110 * or a specific MBEDTLS_ERR_XXX error code
112 int mbedtls_ssl_ticket_setup( mbedtls_ssl_ticket_context *ctx,
113 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
114 mbedtls_cipher_type_t cipher,
118 * \brief Implementation of the ticket write callback
120 * \note See \c mbedtls_ssl_ticket_write_t for description
122 mbedtls_ssl_ticket_write_t mbedtls_ssl_ticket_write;
125 * \brief Implementation of the ticket parse callback
127 * \note See \c mbedtls_ssl_ticket_parse_t for description
129 mbedtls_ssl_ticket_parse_t mbedtls_ssl_ticket_parse;
132 * \brief Free a context's content and zeroize it.
134 * \param ctx Context to be cleaned up
136 void mbedtls_ssl_ticket_free( mbedtls_ssl_ticket_context *ctx );
142 #endif /* ssl_ticket.h */