1 /* 2 * Copyright (C) 2004-2007, 2009 Internet Systems Consortium, Inc. ("ISC") 3 * Copyright (C) 1999-2001 Internet Software Consortium. 4 * 5 * Permission to use, copy, modify, and/or distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 15 * PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 /* $Id: random.h,v 1.20 2009/01/17 23:47:43 tbox Exp $ */ 19 20 #ifndef ISC_RANDOM_H 21 #define ISC_RANDOM_H 1 22 23 #include <isc/lang.h> 24 #include <isc/types.h> 25 26 /*! \file isc/random.h 27 * \brief Implements a random state pool which will let the caller return a 28 * series of possibly non-reproducible random values. 29 * 30 * Note that the 31 * strength of these numbers is not all that high, and should not be 32 * used in cryptography functions. It is useful for jittering values 33 * a bit here and there, such as timeouts, etc. 34 */ 35 36 ISC_LANG_BEGINDECLS 37 38 void 39 isc_random_seed(isc_uint32_t seed); 40 /*%< 41 * Set the initial seed of the random state. 42 */ 43 44 void 45 isc_random_get(isc_uint32_t *val); 46 /*%< 47 * Get a random value. 48 * 49 * Requires: 50 * val != NULL. 51 */ 52 53 isc_uint32_t 54 isc_random_jitter(isc_uint32_t max, isc_uint32_t jitter); 55 /*%< 56 * Get a random value between (max - jitter) and (max). 57 * This is useful for jittering timer values. 58 */ 59 60 ISC_LANG_ENDDECLS 61 62 #endif /* ISC_RANDOM_H */ 63