1 /**
2  * \file entropy_poll.h
3  *
4  * \brief Platform-specific and custom entropy polling functions
5  */
6 /*
7  *  Copyright The Mbed TLS Contributors
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 #ifndef MBEDTLS_ENTROPY_POLL_H
23 #define MBEDTLS_ENTROPY_POLL_H
24 
25 #include "mbedtls/build_info.h"
26 
27 #include <stddef.h>
28 
29 #ifdef __cplusplus
30 extern "C" {
31 #endif
32 
33 /*
34  * Default thresholds for built-in sources, in bytes
35  */
36 #define MBEDTLS_ENTROPY_MIN_PLATFORM     32     /**< Minimum for platform source    */
37 #if !defined(MBEDTLS_ENTROPY_MIN_HARDWARE)
38 #define MBEDTLS_ENTROPY_MIN_HARDWARE     32     /**< Minimum for the hardware source */
39 #endif
40 
41 #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
42 /**
43  * \brief           Platform-specific entropy poll callback
44  */
45 int mbedtls_platform_entropy_poll( void *data,
46                            unsigned char *output, size_t len, size_t *olen );
47 #endif
48 
49 #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
50 /**
51  * \brief           Entropy poll callback for a hardware source
52  *
53  * \warning         This is not provided by mbed TLS!
54  *                  See \c MBEDTLS_ENTROPY_HARDWARE_ALT in mbedtls_config.h.
55  *
56  * \note            This must accept NULL as its first argument.
57  */
58 int mbedtls_hardware_poll( void *data,
59                            unsigned char *output, size_t len, size_t *olen );
60 #endif
61 
62 #if defined(MBEDTLS_ENTROPY_NV_SEED)
63 /**
64  * \brief           Entropy poll callback for a non-volatile seed file
65  *
66  * \note            This must accept NULL as its first argument.
67  */
68 int mbedtls_nv_seed_poll( void *data,
69                           unsigned char *output, size_t len, size_t *olen );
70 #endif
71 
72 #ifdef __cplusplus
73 }
74 #endif
75 
76 #endif /* entropy_poll.h */
77