/* * 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 COPYRIGHT * HOLDER 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. */ /** * random state structure. */ struct ub_randstate; /** * Initialize the system randomness. Obtains entropy from the system * before a chroot or privilege makes it unavailable. * You do not have to call this, otherwise ub_initstate does so. * @param seed: seed value to create state (if no good entropy is found). */ void ub_systemseed(unsigned int seed); /** * Initialize a random generator state for use * @param seed: seed value to create state contents. * (ignored for arc4random). * @param from: if not NULL, the seed is taken from this random structure. * can be used to seed random states via a parent-random-state that * is itself seeded with entropy. * @return new state or NULL alloc failure. */ struct ub_randstate* ub_initstate(unsigned int seed, struct ub_randstate* from); /** * 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); /** * Generate random number between 0 and x-1. No modulo bias. * @param state: must have been initialised with ub_initstate. * @param x: an upper limit. not (negative or zero). must be smaller than 2**31. * @return: random value between 0..x-1. Possibly more than one * random number is picked from the random stream to satisfy this. */ long int ub_random_max(struct ub_randstate* state, long int x); /** * Delete the random state. * @param state: to delete. */ void ub_randfree(struct ub_randstate* state); #endif /* UTIL_RANDOM_H */ |