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ITS#8196/ITS#9714 Switch to xorshift

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Ondřej Kuzník 2022-09-16 14:49:11 +01:00 committed by Quanah Gibson-Mount
parent 034225ff5c
commit 1220282dd5
1 changed files with 28 additions and 15 deletions
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43
libraries/libldap/dnssrv.c
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@ -184,22 +184,28 @@ typedef struct srv_record {
char hostname[MAXHOST];
} srv_record;
/* Linear Congruential Generator - we don't need
* high quality randomness, and we don't want to
/*
* xorshift - we don't need high quality randomness, and we don't want to
* interfere with anyone else's use of srand().
*
* The PRNG here cycles thru 941,955 numbers.
* The PRNG here cycles thru all nonzero 32bit numbers.
*/
static float srv_seed;
static ac_uint4 srv_seed;
static void srv_srand(int seed) {
srv_seed = (float)seed / (float)RAND_MAX;
static void
srv_srand( int seed )
{
srv_seed = seed;
}
static float srv_rand() {
float val = 9821.0 * srv_seed + .211327;
srv_seed = val - (int)val;
return srv_seed;
static ac_uint4
srv_rand( void ) {
ac_uint4 val = srv_seed;
val ^= val << 13;
val ^= val >> 17;
val ^= val << 5;
srv_seed = val;
return val;
}
static int srv_cmp(const void *aa, const void *bb){
@ -221,9 +227,11 @@ static void srv_shuffle(srv_record *a, int n) {
if (!total) {
/* all remaining weights are zero,
do a straight Fisher-Yates shuffle */
j = srv_rand() * p;
j = srv_rand() % p;
} else {
r = srv_rand() * total;
/* Extra share for the first (possibly 0-weight entry),
* RFC2782 Errata (rejected) discusses the effects. */
r = srv_rand() % (total+1);
for (j=0; j<p; j++) {
r -= a[j].weight;
if (r < 0) {
@ -291,10 +299,11 @@ int ldap_domain2hostlist(
unsigned char *p;
char host[DNSBUFSIZ];
int status;
u_short port, priority, weight;
u_short query_id, port, priority, weight;
/* Parse out query */
p = reply;
query_id = (p[0] << 8) | p[1];
#ifdef NS_HFIXEDSZ
/* Bind 8/9 interface */
@ -362,8 +371,12 @@ add_size:;
if (!hostent_head) goto out;
qsort(hostent_head, hostent_count, sizeof(srv_record), srv_cmp);
if (!srv_seed)
srv_srand(time(0L));
if (!srv_seed) {
int seed = time( NULL ) ^ query_id;
/* Make sure we never pass 0 as a seed */
if ( !seed ) seed++;
srv_srand( seed );
}
/* shuffle records of same priority */
j = 0;