Generate a hosts file using DNS64

domains.txt

www.example.com 93.184.216.34

generate_dns64_hosts_file.pl

#!/usr/bin/env perl

use strict;
use Net::IP qw(ip_is_ipv4 ip_is_ipv6 ip_compress_address);

my $domains_file = 'domains.txt';
my $prefixes_file = 'prefixes.txt';

sub convert_ip_to_hex {
  my $prefix = shift;
  my $addr = shift;
  my ($a,$b,$c,$d) = split(/\./, $addr);
  $a = sprintf("%02x", $a);
  $b = sprintf("%02x", $b);
  $c = sprintf("%02x", $c);
  $d = sprintf("%02x", $d);
  my $ip = $a.$b.":".$c.$d;
  my $ip1 = new Net::IP('::'.$ip);
  my $ip2 = new Net::IP($prefix);
  my $ip3 = $ip1->binadd($ip2);
  return ip_compress_address($ip3->ip(),6);
}

my %domains;
open my $fh, '<', $domains_file or die;
while (my $row = <$fh>) {
  chomp $row;
  my ($domain, $ip) = split(/ /,$row);
  push(@{$domains{$domain}},$ip);
}
close $fh;

my @prefixes;
open $fh, '<', $prefixes_file or die;
while (my $row = <$fh>) {
  chomp $row;
  push(@prefixes,$row);
}
close $fh;

foreach my $domain (keys %domains) {
  foreach my $ip (@{$domains{$domain}}){
    foreach my $prefix (@prefixes) {
      if(ip_is_ipv6($prefix) && ip_is_ipv4($ip)) {
        print convert_ip_to_hex($prefix,$ip)." ".$domain."\n";
      }
    }
  }
}

prefixes.txt

2a0b:f4c0:4d:1::
2a0b:f4c0:4d:2::
2a0b:f4c0:4d:3::