unbound/util/random.h
Wouter Wijngaards 9e732da50b Arc4random.
git-svn-id: file:///svn/unbound/trunk@683 be551aaa-1e26-0410-a405-d3ace91eadb9
2007-10-17 12:08:34 +00:00

82 lines
2.7 KiB
C

/*
* util/random.h - thread safe random generator, which is reasonably secure.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef UTIL_RANDOM_H
#define UTIL_RANDOM_H
/**
* \file
* Thread safe random functions. Similar to arc4random() with an explicit
* initialisation routine.
*/
struct ub_hiddenstate;
/**
* random state structure.
*/
struct ub_randstate {
/** state hidden type. */
struct ub_hiddenstate* s;
};
/**
* Initialize a random generator state for use
* @param seed: seed value to create state contents.
* (ignored for arc4random).
* @param state: struct allocated by caller.
* @param n: size of state->state. 8, 32, 64, 128, or 256 bytes.
* (ignored for arc4random).
* @return false alloc failure.
*/
int ub_initstate(unsigned int seed, struct ub_randstate* state,
unsigned long n);
/**
* Generate next random number from the state passed along.
* Thread safe, so random numbers are repeatable.
* @param state: must have been initialised with ub_initstate.
* @return: random 31 bit value.
*/
long int ub_random(struct ub_randstate* state);
/**
* Delete the random state.
* @param state: to delete.
*/
void ub_randfree(struct ub_randstate* state);
#endif /* UTIL_RANDOM_H */