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author | peter <peter@FreeBSD.org> | 2008-07-12 05:00:28 +0000 |
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committer | peter <peter@FreeBSD.org> | 2008-07-12 05:00:28 +0000 |
commit | ba8f85b49c38af7bc2a9acdef5dcde2de008d25e (patch) | |
tree | ceac31a567976fd5866cb5791b059781f6e045de /lib/isc/random.c | |
parent | 0f328cea2580ffb8f9e363be671a517787111472 (diff) | |
download | FreeBSD-src-ba8f85b49c38af7bc2a9acdef5dcde2de008d25e.zip FreeBSD-src-ba8f85b49c38af7bc2a9acdef5dcde2de008d25e.tar.gz |
Flatten bind9 vendor work area
Diffstat (limited to 'lib/isc/random.c')
-rw-r--r-- | lib/isc/random.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/lib/isc/random.c b/lib/isc/random.c new file mode 100644 index 0000000..f6c7d6e --- /dev/null +++ b/lib/isc/random.c @@ -0,0 +1,104 @@ +/* + * Copyright (C) 2004, 2005 Internet Systems Consortium, Inc. ("ISC") + * Copyright (C) 1999-2003 Internet Software Consortium. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +/* $Id: random.c,v 1.21.18.2 2005/04/29 00:16:48 marka Exp $ */ + +/*! \file */ + +#include <config.h> + +#include <stdlib.h> +#include <time.h> /* Required for time(). */ +#ifdef HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif + +#include <isc/mutex.h> +#include <isc/once.h> +#include <isc/random.h> +#include <isc/string.h> +#include <isc/util.h> + +static isc_once_t once = ISC_ONCE_INIT; + +static void +initialize_rand(void) +{ +#ifndef HAVE_ARC4RANDOM + unsigned int pid = getpid(); + + /* + * The low bits of pid generally change faster. + * Xor them with the high bits of time which change slowly. + */ + pid = ((pid << 16) & 0xffff0000) | ((pid >> 16) & 0xffff); + + srand(time(NULL) ^ pid); +#endif +} + +static void +initialize(void) +{ + RUNTIME_CHECK(isc_once_do(&once, initialize_rand) == ISC_R_SUCCESS); +} + +void +isc_random_seed(isc_uint32_t seed) +{ + initialize(); + +#ifndef HAVE_ARC4RANDOM + srand(seed); +#else + arc4random_addrandom((u_char *) &seed, sizeof(isc_uint32_t)); +#endif +} + +void +isc_random_get(isc_uint32_t *val) +{ + REQUIRE(val != NULL); + + initialize(); + +#ifndef HAVE_ARC4RANDOM + /* + * rand()'s lower bits are not random. + * rand()'s upper bit is zero. + */ + *val = ((rand() >> 4) & 0xffff) | ((rand() << 12) & 0xffff0000); +#else + *val = arc4random(); +#endif +} + +isc_uint32_t +isc_random_jitter(isc_uint32_t max, isc_uint32_t jitter) { + REQUIRE(jitter < max); + if (jitter == 0) + return (max); + else +#ifndef HAVE_ARC4RANDOM + return (max - rand() % jitter); +#else + return (max - arc4random() % jitter); +#endif +} |