entropy.h

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/*
 *  Copyright (C) 2006-2016, 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_ENTROPY_H
#define MBEDTLS_ENTROPY_H

#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#include <stddef.h>

#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256)
#include "mbedtls/sha512.h"
#define MBEDTLS_ENTROPY_SHA512_ACCUMULATOR
#else
#if defined(MBEDTLS_SHA256_C)
#define MBEDTLS_ENTROPY_SHA256_ACCUMULATOR
#include "mbedtls/sha256.h"
#endif
#endif

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

#if defined(MBEDTLS_HAVEGE_C)
#include "mbedtls/havege.h"
#endif

#define MBEDTLS_ERR_ENTROPY_SOURCE_FAILED                 -0x003C  
#define MBEDTLS_ERR_ENTROPY_MAX_SOURCES                   -0x003E  
#define MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED            -0x0040  
#define MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE              -0x003D  
#define MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR                 -0x003F  
#if !defined(MBEDTLS_ENTROPY_MAX_SOURCES)
#define MBEDTLS_ENTROPY_MAX_SOURCES     20      
#endif

#if !defined(MBEDTLS_ENTROPY_MAX_GATHER)
#define MBEDTLS_ENTROPY_MAX_GATHER      128     
#endif

#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
#define MBEDTLS_ENTROPY_BLOCK_SIZE      64      
#else
#define MBEDTLS_ENTROPY_BLOCK_SIZE      32      
#endif

#define MBEDTLS_ENTROPY_MAX_SEED_SIZE   1024    
#define MBEDTLS_ENTROPY_SOURCE_MANUAL   MBEDTLS_ENTROPY_MAX_SOURCES

#define MBEDTLS_ENTROPY_SOURCE_STRONG   1       
#define MBEDTLS_ENTROPY_SOURCE_WEAK     0       
#ifdef __cplusplus
extern "C" {
#endif

typedef int (*mbedtls_entropy_f_source_ptr)(void *data, unsigned char *output, size_t len,
                            size_t *olen);

typedef struct mbedtls_entropy_source_state
{
    mbedtls_entropy_f_source_ptr    f_source;   
    void *          p_source;   
    size_t          size;       
    size_t          threshold;  
    int             strong;     
}
mbedtls_entropy_source_state;

typedef struct mbedtls_entropy_context
{
    int accumulator_started;
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
    mbedtls_sha512_context  accumulator;
#else
    mbedtls_sha256_context  accumulator;
#endif
    int             source_count;
    mbedtls_entropy_source_state    source[MBEDTLS_ENTROPY_MAX_SOURCES];
#if defined(MBEDTLS_HAVEGE_C)
    mbedtls_havege_state    havege_data;
#endif
#if defined(MBEDTLS_THREADING_C)
    mbedtls_threading_mutex_t mutex;    
#endif
#if defined(MBEDTLS_ENTROPY_NV_SEED)
    int initial_entropy_run;
#endif
}
mbedtls_entropy_context;

void mbedtls_entropy_init( mbedtls_entropy_context *ctx );

void mbedtls_entropy_free( mbedtls_entropy_context *ctx );

int mbedtls_entropy_add_source( mbedtls_entropy_context *ctx,
                        mbedtls_entropy_f_source_ptr f_source, void *p_source,
                        size_t threshold, int strong );

int mbedtls_entropy_gather( mbedtls_entropy_context *ctx );

int mbedtls_entropy_func( void *data, unsigned char *output, size_t len );

int mbedtls_entropy_update_manual( mbedtls_entropy_context *ctx,
                           const unsigned char *data, size_t len );

#if defined(MBEDTLS_ENTROPY_NV_SEED)

int mbedtls_entropy_update_nv_seed( mbedtls_entropy_context *ctx );
#endif /* MBEDTLS_ENTROPY_NV_SEED */

#if defined(MBEDTLS_FS_IO)

int mbedtls_entropy_write_seed_file( mbedtls_entropy_context *ctx, const char *path );

int mbedtls_entropy_update_seed_file( mbedtls_entropy_context *ctx, const char *path );
#endif /* MBEDTLS_FS_IO */

#if defined(MBEDTLS_SELF_TEST)

int mbedtls_entropy_self_test( int verbose );

#if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)

int mbedtls_entropy_source_self_test( int verbose );
#endif /* MBEDTLS_ENTROPY_HARDWARE_ALT */
#endif /* MBEDTLS_SELF_TEST */

#ifdef __cplusplus
}
#endif

#endif /* entropy.h */