88 lines
1.8 KiB
C
88 lines
1.8 KiB
C
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/* prng.h -- Pseudo Random Numbers
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*
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* Copyright (C) 2010--2012 Olaf Bergmann <bergmann@tzi.org>
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*
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* This file is part of the library tinydtls. Please see
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* README for terms of use.
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*/
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/**
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* @file prng.h
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* @brief Pseudo Random Numbers
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*/
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#ifndef _DTLS_PRNG_H_
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#define _DTLS_PRNG_H_
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#include "tinydtls.h"
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/**
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* @defgroup prng Pseudo Random Numbers
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* @{
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*/
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#ifndef WITH_CONTIKI
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#include <stdlib.h>
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/**
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* Fills \p buf with \p len random bytes. This is the default
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* implementation for prng(). You might want to change prng() to use
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* a better PRNG on your specific platform.
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*/
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static inline int
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dtls_prng(unsigned char *buf, size_t len) {
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while (len--)
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*buf++ = rand() & 0xFF;
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return 1;
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}
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static inline void
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dtls_prng_init(unsigned short seed) {
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srand(seed);
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}
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#else /* WITH_CONTIKI */
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#include <string.h>
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#include "random.h"
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#ifdef HAVE_PRNG
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static inline int
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dtls_prng(unsigned char *buf, size_t len)
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{
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return contiki_prng_impl(buf, len);
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}
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#else
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/**
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* Fills \p buf with \p len random bytes. This is the default
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* implementation for prng(). You might want to change prng() to use
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* a better PRNG on your specific platform.
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*/
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static inline int
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dtls_prng(unsigned char *buf, size_t len) {
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unsigned short v = random_rand();
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while (len > sizeof(v)) {
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memcpy(buf, &v, sizeof(v));
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len -= sizeof(v);
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buf += sizeof(v);
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v = random_rand();
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}
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memcpy(buf, &v, len);
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return 1;
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}
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#endif /* HAVE_PRNG */
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static inline void
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dtls_prng_init(unsigned short seed) {
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/* random_init() messes with the radio interface of the CC2538 and
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* therefore must not be called after the radio has been
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* initialized. */
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#ifndef CONTIKI_TARGET_CC2538DK
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random_init(seed);
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#endif
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}
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#endif /* WITH_CONTIKI */
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/** @} */
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#endif /* _DTLS_PRNG_H_ */
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