#!/usr/local/bin/perl

use Jcode;
use Convert::RACE 'to_race';
use Socket;

open(LOG, ">>/tmp/dnsserver.log");
select(LOG);
$| = 1;
select(STDOUT);
$| = 1;

sub log {
  my $mes = shift;

  flock(LOG, 2);
  seek(LOG, 0, 2);
  print LOG $mes;
  flock(LOG, 8);
}


while(<STDIN>)
  {
    chomp;
    tr/\r//d;

    &log("<< $_\n");
    
    if(m/^\$hello/)
      {
	print '$alive' . "\n";
	next;
      }
    if(m/^\$shutdown/)
      {
	exit(0);
      }

    if(m/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/)
      {
	my $name = gethostbyaddr(pack('CCCC', $1, $2, $3, $4), AF_INET);
	if(defined($name))
	  {
	    print '$addr 0 ' . $name . "\n";
	    &log("resolv: $name\n");
	  }
	else
	  {
	    print '$fail DNS Domain PTR ' . "'$_' is invalid\n";
	  }
	next;
      }

    my $name;
    my $race;
    foreach $n (split(/\./, $_))
      {
	eval {
	  $race .= to_race(Jcode->new($n, 'sjis')->ucs2) . '.';
	};
	if ($@)
	  {
	    $race .= $n . '.';
	  }
      }
    chop $race;
#    $race = uc($race);
    &log("race: $race\n");
    $name = join('.', unpack('CCCC', gethostbyname($race)));
#    chop $race;

    if(defined($name) and $name ne '')
      {
	print '$addr 0 ' . $name . "\n";
	&log("resolv: $name\n");
      }
    else
      {
	print '$fail DNS Domain ' . "'$race' is invalid\n";
	&log("unresolv: $race\n");
      }
  }