($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
          }, # soa
    11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks
    12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
    13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
    15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx
    16 => sub { unpack "(C/a*)*", $_ }, # txt
    28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
    33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv
    35 => sub { # naptr
       # requires perl 5.10, sorry
       my ($order, $preference, $flags, $service, $regexp, $offset) = unpack "nn C/a* C/a* C/a* .", $_;
       local $ofs = $ofs + $offset - length;
       ($order, $preference, $flags, $service, $regexp, _dec_name)
    },
    99 => sub { unpack "(C/a*)*", $_ }, # spf
);

sub _dec_rr {
   my $name = _dec_name;

   my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;
   local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;

   [
      $name,
      $type_str{$rt}  || $rt,
      $class_str{$rc} || $rc,
      ($dec_rr{$rt} || sub { $_ })->(),
   ]
}

=item $dns = AnyEvent::DNS::dns_unpack $pkt

Unpacks a DNS packet into a perl data structure.

Examples:

   # an unsuccessful reply
   {
     'qd' => [
               [ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
             ],
     'rc' => 'nxdomain',
     'ar' => [],
     'ns' => [
               [
                 'uni-karlsruhe.de',
                 'soa',
                 'in',
                 'netserv.rz.uni-karlsruhe.de',
                 'hostmaster.rz.uni-karlsruhe.de',
                 2008052201, 10800, 1800, 2592000, 86400
               ]
             ],
     'tc' => '',
     'ra' => 1,
     'qr' => 1,
     'id' => 45915,
     'aa' => '',
     'an' => [],
     'rd' => 1,
     'op' => 'query'
   }
   
   # a successful reply
   
   {
     'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
     'rc' => 0,
     'ar' => [
               [ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
               [ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
               [ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
             ],
     'ns' => [
               [ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
               [ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
             ],
     'tc' => '',
     'ra' => 1,
     'qr' => 1,
     'id' => 64265,
     'aa' => '',
     'an' => [
               [ 'www.google.de', 'cname', 'in', 'www.google.com' ],
               [ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
               [ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
               [ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
             ],
     'rd' => 1,
     'op' => 0
   }

=cut

sub dns_unpack($) {
   local $pkt = shift;
   my ($id, $flags, $qd, $an, $ns, $ar)
      = unpack "nn nnnn A*", $pkt;