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85 lines
1.7 KiB
C
85 lines
1.7 KiB
C
/* prng.h -- Pseudo Random Numbers
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*
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* Copyright (C) 2010,2011 Olaf Bergmann <bergmann@tzi.org>
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*
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* This file is part of the CoAP library libcoap. 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 _COAP_PRNG_H_
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#define _COAP_PRNG_H_
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#include "config.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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coap_prng_impl(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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#else /* WITH_CONTIKI */
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#include <string.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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contiki_prng_impl(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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}
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memcpy(buf, &v, len);
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return 1;
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}
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#define prng(Buf,Length) contiki_prng_impl((Buf), (Length))
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#define prng_init(Value) random_init((unsigned short)(Value))
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#endif /* WITH_CONTIKI */
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#ifndef prng
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/**
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* Fills \p Buf with \p Length bytes of random data.
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*
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* @hideinitializer
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*/
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#define prng(Buf,Length) coap_prng_impl((Buf), (Length))
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#endif
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#ifndef prng_init
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/**
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* Called to set the PRNG seed. You may want to re-define this to
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* allow for a better PRNG.
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*
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* @hideinitializer
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*/
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#define prng_init(Value) srand((unsigned long)(Value))
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#endif
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/** @} */
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#endif /* _COAP_PRNG_H_ */
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