void
dnsparse::srvrec_randomize (srvrec *base, srvrec *last)
{
qsort (base, last - base, sizeof (*base), &srvrec_cmp);
#if 0
for (srvrec *x = base; x < last; x++)
warn ("DBG: %3d %3d %5d %s\n", x->prio, x->weight, x->port, x->name);
#endif
while (base < last) {
srvrec *lastprio = base;
u_int totweight;
/* It's not clear from RFC 2782 if we need to randomize multiple
* records with weight 0 at the same priority. We do it anyway
* just because it might be helpful. */
if (base->weight == 0) {
totweight = 1;
while (++lastprio < last && lastprio->prio == base->prio)
totweight++;
while (base + 1 < lastprio) {
u_int which = arandom () % totweight;
if (which) {
srvrec tmp = base[which];
base[which] = *base;
*base = tmp;
}
base++;
totweight--;
}
}
else {
totweight = lastprio->weight;
while (++lastprio < last && lastprio->weight
&& lastprio->prio == base->prio)
totweight += lastprio->weight;
while (base + 1 < lastprio) {
u_int32_t rndweight = arandom () % totweight + 1;
srvrec *nextrec;
for (nextrec = base; nextrec->weight < rndweight; nextrec++)
rndweight -= nextrec->weight;
srvrec tmp = *base;
*base = *nextrec;
*nextrec = tmp;
totweight -= base++->weight;
}
assert (totweight == base->weight);
}
base++;
}
}
u_int16_t
resolver::genid ()
{
u_int16_t id;
int i = 0;
do {
id = arandom () % 0xffff;
} while (reqtab[id] && ++i < 8);
return id;
}