diff options
Diffstat (limited to 'lib/isc/random.c')
| -rw-r--r-- | lib/isc/random.c | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/lib/isc/random.c b/lib/isc/random.c index 4ed13d97..a4251561 100644 --- a/lib/isc/random.c +++ b/lib/isc/random.c @@ -15,11 +15,12 @@ * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ -/* $Id: random.c,v 1.15 2001/01/09 21:56:22 bwelling Exp $ */ +/* $Id: random.c,v 1.15.2.2 2003/08/05 03:09:52 marka Exp $ */ #include <config.h> #include <stdlib.h> +#include <unistd.h> #include <time.h> /* Required for time(). */ #include <isc/mutex.h> @@ -33,7 +34,17 @@ static isc_once_t once = ISC_ONCE_INIT; static void initialize_rand(void) { - srand(time(NULL)); +#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 @@ -47,7 +58,11 @@ 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 @@ -57,7 +72,15 @@ isc_random_get(isc_uint32_t *val) initialize(); - *val = rand(); +#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 @@ -66,5 +89,9 @@ isc_random_jitter(isc_uint32_t max, isc_uint32_t jitter) { if (jitter == 0) return (max); else +#ifndef HAVE_ARC4RANDOM return (max - rand() % jitter); +#else + return (max - arc4random() % jitter); +#endif } |