1 /**
2  * \file ssl_cache.h
3  *
4  * \brief SSL session cache implementation
5  */
6 /*
7  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
8  *  SPDX-License-Identifier: Apache-2.0
9  *
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
13  *
14  *  http://www.apache.org/licenses/LICENSE-2.0
15  *
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.
21  *
22  *  This file is part of mbed TLS (https://tls.mbed.org)
23  */
24 #ifndef MBEDTLS_SSL_CACHE_H
25 #define MBEDTLS_SSL_CACHE_H
26 
27 #include "ssl.h"
28 
29 #if defined(MBEDTLS_THREADING_C)
30 #include "threading.h"
31 #endif
32 
33 /**
34  * \name SECTION: Module settings
35  *
36  * The configuration options you can set for this module are in this section.
37  * Either change them in config.h or define them on the compiler command line.
38  * \{
39  */
40 
41 #if !defined(MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT)
42 #define MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT       86400   /*!< 1 day  */
43 #endif
44 
45 #if !defined(MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES)
46 #define MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES      50   /*!< Maximum entries in cache */
47 #endif
48 
49 /* \} name SECTION: Module settings */
50 
51 #ifdef __cplusplus
52 extern "C" {
53 #endif
54 
55 typedef struct mbedtls_ssl_cache_context mbedtls_ssl_cache_context;
56 typedef struct mbedtls_ssl_cache_entry mbedtls_ssl_cache_entry;
57 
58 /**
59  * \brief   This structure is used for storing cache entries
60  */
61 struct mbedtls_ssl_cache_entry
62 {
63 #if defined(MBEDTLS_HAVE_TIME)
64     mbedtls_time_t timestamp;           /*!< entry timestamp    */
65 #endif
66     mbedtls_ssl_session session;        /*!< entry session      */
67 #if defined(MBEDTLS_X509_CRT_PARSE_C)
68     mbedtls_x509_buf peer_cert;         /*!< entry peer_cert    */
69 #endif
70     mbedtls_ssl_cache_entry *next;      /*!< chain pointer      */
71 };
72 
73 /**
74  * \brief Cache context
75  */
76 struct mbedtls_ssl_cache_context
77 {
78     mbedtls_ssl_cache_entry *chain;     /*!< start of the chain     */
79     int timeout;                /*!< cache entry timeout    */
80     int max_entries;            /*!< maximum entries        */
81 #if defined(MBEDTLS_THREADING_C)
82     mbedtls_threading_mutex_t mutex;    /*!< mutex                  */
83 #endif
84 };
85 
86 /**
87  * \brief          Initialize an SSL cache context
88  *
89  * \param cache    SSL cache context
90  */
91 void mbedtls_ssl_cache_init( mbedtls_ssl_cache_context *cache );
92 
93 /**
94  * \brief          Cache get callback implementation
95  *                 (Thread-safe if MBEDTLS_THREADING_C is enabled)
96  *
97  * \param data     SSL cache context
98  * \param session  session to retrieve entry for
99  */
100 int mbedtls_ssl_cache_get( void *data, mbedtls_ssl_session *session );
101 
102 /**
103  * \brief          Cache set callback implementation
104  *                 (Thread-safe if MBEDTLS_THREADING_C is enabled)
105  *
106  * \param data     SSL cache context
107  * \param session  session to store entry for
108  */
109 int mbedtls_ssl_cache_set( void *data, const mbedtls_ssl_session *session );
110 
111 #if defined(MBEDTLS_HAVE_TIME)
112 /**
113  * \brief          Set the cache timeout
114  *                 (Default: MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT (1 day))
115  *
116  *                 A timeout of 0 indicates no timeout.
117  *
118  * \param cache    SSL cache context
119  * \param timeout  cache entry timeout in seconds
120  */
121 void mbedtls_ssl_cache_set_timeout( mbedtls_ssl_cache_context *cache, int timeout );
122 #endif /* MBEDTLS_HAVE_TIME */
123 
124 /**
125  * \brief          Set the maximum number of cache entries
126  *                 (Default: MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES (50))
127  *
128  * \param cache    SSL cache context
129  * \param max      cache entry maximum
130  */
131 void mbedtls_ssl_cache_set_max_entries( mbedtls_ssl_cache_context *cache, int max );
132 
133 /**
134  * \brief          Free referenced items in a cache context and clear memory
135  *
136  * \param cache    SSL cache context
137  */
138 void mbedtls_ssl_cache_free( mbedtls_ssl_cache_context *cache );
139 
140 #ifdef __cplusplus
141 }
142 #endif
143 
144 #endif /* ssl_cache.h */
145