107 lines
2.2 KiB
C
107 lines
2.2 KiB
C
/*
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* 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 README for terms
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* 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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/**
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* @defgroup prng Pseudo Random Numbers
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* @{
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*/
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#if defined(WITH_POSIX) || (defined(WITH_LWIP) && !defined(LWIP_RAND))
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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 implementation for
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* prng(). You might want to change prng() to use a better PRNG on your specific
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* 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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#endif /* WITH_POSIX */
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#ifdef 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 implementation for
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* prng(). You might want to change prng() to use a better PRNG on your specific
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* 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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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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#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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#if defined(WITH_LWIP) && defined(LWIP_RAND)
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static inline int
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lwip_prng_impl(unsigned char *buf, size_t len) {
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u32_t v = LWIP_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 = LWIP_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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#define prng(Buf,Length) lwip_prng_impl((Buf), (Length))
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#define prng_init(Value)
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#endif /* WITH_LWIP */
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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 allow for a
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* 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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