if (v0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0 eq $_[0]) {
         return "::";
      } elsif (v0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1 eq $_[0]) {
         return "::1";
      } elsif (v0.0.0.0.0.0.0.0.0.0.0.0 eq substr $_[0], 0, 12) {
         # v4compatible
         return "::" . format_address substr $_[0], 12;
      } elsif (v0.0.0.0.0.0.0.0.0.0.255.255 eq substr $_[0], 0, 12) {
         # v4mapped
         return "::ffff:" . format_address substr $_[0], 12;
      } elsif (v0.0.0.0.0.0.0.0.255.255.0.0 eq substr $_[0], 0, 12) {
         # v4translated
         return "::ffff:0:" . format_address substr $_[0], 12;
      } else {
         my $ip = sprintf "%x:%x:%x:%x:%x:%x:%x:%x", unpack "n8", $_[0];

         # this is rather sucky, I admit
         $ip =~ s/^0:(?:0:)*(0$)?/::/
            or $ip =~ s/(:0){7}$/::/ or $ip =~ s/(:0){7}/:/
            or $ip =~ s/(:0){6}$/::/ or $ip =~ s/(:0){6}/:/
            or $ip =~ s/(:0){5}$/::/ or $ip =~ s/(:0){5}/:/
            or $ip =~ s/(:0){4}$/::/ or $ip =~ s/(:0){4}/:/
            or $ip =~ s/(:0){3}$/::/ or $ip =~ s/(:0){3}/:/
            or $ip =~ s/(:0){2}$/::/ or $ip =~ s/(:0){2}/:/
            or $ip =~ s/(:0){1}$/::/ or $ip =~ s/(:0){1}/:/;
         return $ip
      }
   } elsif ($af == AF_UNIX) {
      return "unix/"
   } else {
      return undef
   }
}

*format_ip = \&format_address;

=item inet_aton $name_or_address, $cb->(@addresses)

Works similarly to its Socket counterpart, except that it uses a
callback. Also, if a host has only an IPv6 address, this might be passed
to the callback instead (use the length to detect this - 4 for IPv4, 16
for IPv6).

Unlike the L<Socket> function of the same name, you can get multiple IPv4
and IPv6 addresses as result (and maybe even other adrdess types).

=cut

sub inet_aton {
   my ($name, $cb) = @_;

   if (my $ipn = &parse_ipv4) {
      $cb->($ipn);
   } elsif (my $ipn = &parse_ipv6) {
      $cb->($ipn);
   } elsif ($name eq "localhost") { # rfc2606 et al.
      $cb->(v127.0.0.1, v0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1);
   } else {
      require AnyEvent::DNS;

      # simple, bad suboptimal algorithm
      AnyEvent::DNS::a ($name, sub {
         if (@_) {
            $cb->(map +(parse_ipv4 $_), @_);
         } else {
            $cb->();
            #AnyEvent::DNS::aaaa ($name, $cb); need inet_pton
         }
      });
   }
}

# check for broken platforms with extra field in sockaddr structure
# kind of a rfc vs. bsd issue, as usual (ok, normally it's a
# unix vs. bsd issue, a iso C vs. bsd issue or simply a
# correctness vs. bsd issue.
my $pack_family = (0x55 == Socket::sockaddr_family "\x55\x55")
                  ? "xC" : "S";

=item $sa = AnyEvent::Socket::pack_sockaddr $service, $host

Pack the given port/host combination into a binary sockaddr
structure. Handles both IPv4 and IPv6 host addresses, as well as UNIX
domain sockets (C<$host> == C<unix/> and C<$service> == absolute
pathname).

=cut

sub pack_sockaddr($$) {
   my $af = address_family $_[1];

   if ($af == AF_INET) {
      Socket::pack_sockaddr_in $_[0], $_[1]
   } elsif ($af == AF_INET6) {
      pack "$pack_family nL a16 L",
         AF_INET6,
         $_[0], # port
         0,     # flowinfo
         $_[1], # addr
         0      # scope id