131 lines
3.5 KiB
C
131 lines
3.5 KiB
C
/*
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* Copyright (C) 2004-2007, 2009, 2014 Internet Systems Consortium, Inc. ("ISC")
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* Copyright (C) 1999-2001 Internet Software Consortium.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
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* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
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* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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/* $Id: random.h,v 1.20 2009/01/17 23:47:43 tbox Exp $ */
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#ifndef ISC_RANDOM_H
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#define ISC_RANDOM_H 1
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#include <isc/lang.h>
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#include <isc/types.h>
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#include <isc/entropy.h>
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#include <isc/mem.h>
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#include <isc/mutex.h>
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/*! \file isc/random.h
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* \brief Implements a random state pool which will let the caller return a
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* series of possibly non-reproducible random values.
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*
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* Note that the
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* strength of these numbers is not all that high, and should not be
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* used in cryptography functions. It is useful for jittering values
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* a bit here and there, such as timeouts, etc.
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*/
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ISC_LANG_BEGINDECLS
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typedef struct isc_rng isc_rng_t;
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/*%<
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* Opaque type
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*/
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void
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isc_random_seed(isc_uint32_t seed);
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/*%<
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* Set the initial seed of the random state.
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*/
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void
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isc_random_get(isc_uint32_t *val);
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/*%<
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* Get a random value.
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*
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* Requires:
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* val != NULL.
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*/
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isc_uint32_t
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isc_random_jitter(isc_uint32_t max, isc_uint32_t jitter);
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/*%<
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* Get a random value between (max - jitter) and (max).
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* This is useful for jittering timer values.
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*/
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isc_result_t
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isc_rng_create(isc_mem_t *mctx, isc_entropy_t *entropy, isc_rng_t **rngp);
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/*%<
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* Creates and initializes a pseudo random number generator. The
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* returned RNG can be used to generate pseudo random numbers.
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*
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* The reference count of the returned RNG is set to 1.
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*
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* Requires:
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* \li mctx is a pointer to a valid memory context.
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* \li entropy is an optional entopy source (can be NULL)
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* \li rngp != NULL && *rngp == NULL is where a pointer to the RNG is
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* returned.
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*
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* Ensures:
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*\li If result is ISC_R_SUCCESS:
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* *rngp points to a valid RNG.
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*
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*\li If result is failure:
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* *rngp does not point to a valid RNG.
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*
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* Returns:
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*\li #ISC_R_SUCCESS Success
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*\li #ISC_R_NOMEMORY Resource limit: Out of Memory
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*/
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void
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isc_rng_attach(isc_rng_t *source, isc_rng_t **targetp);
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/*%<
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* Increments a reference count on the passed RNG.
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*
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* Requires:
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* \li source the RNG struct to attach to (is refcount is incremented)
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* \li targetp != NULL && *targetp == NULL where a pointer to the
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* reference incremented RNG is returned.
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*/
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void
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isc_rng_detach(isc_rng_t **rngp);
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/*%<
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* Decrements a reference count on the passed RNG. If the reference
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* count reaches 0, the RNG is destroyed.
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*
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* Requires:
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* \li rngp != NULL the RNG struct to decrement reference for
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*/
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isc_uint16_t
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isc_rng_random(isc_rng_t *rngctx);
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/*%<
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* Returns a pseudo random 16-bit unsigned integer.
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*/
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isc_uint16_t
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isc_rng_uniformrandom(isc_rng_t *rngctx, isc_uint16_t upper_bound);
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/*%<
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* Returns a uniformly distributed pseudo random 16-bit unsigned
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* integer.
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*/
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ISC_LANG_ENDDECLS
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#endif /* ISC_RANDOM_H */
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