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#include "byte.h"
#include "dnsresolv.h"
#include "ip.h"
/**
@file dns_sortip.c
@authors djb, fefe, feh
@ref ucspi-tcp6
@brief random sort of DNS servers per IP
*/
/* XXX: sort servers by configurable notion of closeness? */
/* XXX: pay attention to competence of each server? */
/* XXX: pay attention to qualification (DNSSec, DNSCurve) of each server? */
/* YYY: we use a randomly sorted list of NS; not depending on answer */
void dns_sortip4(char *s, unsigned int n)
{
unsigned int i;
char tmp[4];
n >>= 2; // 4 byte per IPv4 address
while (n > 1) {
i = dns_random(n);
--n;
byte_copy(tmp, 4, s + (i << 2));
byte_copy(s + (i << 2), 4, s + (n << 2));
byte_copy(s + (n << 2), 4, tmp);
}
}
void dns_sortip6(char *s, unsigned int n)
{
unsigned int i;
char tmp[16];
n >>= 4; // 16 byte per IPv4 address
while (n > 1) {
i = dns_random(n);
--n;
byte_copy(tmp, 16, s + (i << 4));
byte_copy(s + (i << 4), 16, s + (n << 4));
byte_copy(s + (n << 4), 16, tmp);
}
}
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