/*
* Copyright (c) 2016 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
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*/
#ifndef _RAND_H
#define _RAND_H
#include <libkern/crypto/crypto.h>
__BEGIN_DECLS
// A handle to a random generator suitable for use with
// crypto_random_generate.
typedef void *crypto_random_ctx_t;
// The maximum size (in bytes) of a random generator.
#define CRYPTO_RANDOM_MAX_CTX_SIZE ((size_t)256)
typedef void (*crypto_random_generate_fn_t)(
crypto_random_ctx_t ctx,
void *random,
size_t random_size);
typedef void (*crypto_random_uniform_fn_t)(
crypto_random_ctx_t ctx,
uint64_t bound,
uint64_t *random);
typedef size_t (*crypto_random_kmem_ctx_size_fn_t)(void);
typedef void (*crypto_random_kmem_init_fn_t)(
crypto_random_ctx_t ctx);
#if XNU_KERNEL_PRIVATE
int cc_rand_generate(void *out, size_t outlen);
// Generate random data with the supplied handle to a random
// generator. The behavior of this function (e.g. the quality of the
// randomness, whether it might acquire a lock, the cryptographic
// primitives used) depends on the semantics of the generator.
void crypto_random_generate(
crypto_random_ctx_t ctx,
void *random,
size_t random_size);
// Generate a random value in the range [0, bound), i.e. including
// zero and excluding the bound. The generated value is stored in the
// random pointer which should point to a single value. As above, the
// behavior of this function depends in part on the semantics of the
// generator.
void crypto_random_uniform(
crypto_random_ctx_t ctx,
uint64_t bound,
uint64_t *random);
// The following two functions are for use in the kmem subsystem
// only. They are NOT guaranteed to provide cryptographic randomness
// and should not be used elsewhere.
// Return the size needed for a random generator to be used by
// kmem. (See the discussion below for the semantics of this
// generator.)
//
// The returned value may vary by platform, but it is guaranteed to be
// no larger than CRYPTO_RANDOM_MAX_CTX_SIZE.
size_t crypto_random_kmem_ctx_size(void);
// Initialize the handle with a random generator for use by kmem. This
// function should only be called by kmem.
//
// The handle should point to memory at least as large as
// crypto_random_kmem_ctx_size() indicates.
//
// This generator is NOT guaranteed to provide cryptographic
// randomness.
//
// The initialized generator is guaranteed not to acquire a
// lock. (Note, however, that this initialization function MAY acquire
// a lock.)
//
// The initialized generator is guaranteed not to touch FP registers
// on Intel.
void crypto_random_kmem_init(
crypto_random_ctx_t ctx);
#endif /* XNU_KERNEL_PRIVATE */
int random_buf(void *buf, size_t buflen);
__END_DECLS
#endif