NAME
    NetAddr::IP::Util -- IPv4/6 and 128 bit number utilities

SYNOPSIS
      use NetAddr::IP::Util qw(
            inet_aton
            inet_ntoa
            ipv6_aton
            ipv6_n2x
            ipv6_n2d
            inet_any2n
            hasbits
            isIPv4
            inet_n2dx
            inet_n2ad
            ipv4to6
            mask4to6
            ipanyto6
            maskanyto6
            ipv6to4
            shiftleft
            addconst
            add128
            sub128
            notcontiguous
            bin2bcd
            bcd2bin
            mode
      );

      use NetAddr::IP::Util qw(:all :inet :ipv4 :ipv6 :math)

      :inet   =>    inet_aton, inet_ntoa, ipv6_aton,
                    ipv6_n2x, ipv6_n2d, inet_any2n, 
                    inet_n2dx, inet_n2ad, ipv4to6,
                    mask4to6, ipanyto6, maskanyto6,
                    ipv6to4

      :ipv4   =>    inet_aton, inet_ntoa

      :ipv6   =>    ipv6_aton, ipv6_n2x, ipv6_n2d,
                    inet_any2n, inet_n2dx, inet_n2ad
                    ipv4to6, mask4to6, ipanyto6,
                    maskanyto6, ipv6to4

      :math   =>    hasbits, isIPv4, addconst,
                    add128, sub128, notcontiguous,
                    bin2bcd, bcd2bin, shiftleft

      $dotquad = inet_ntoa($netaddr);
      $netaddr = inet_aton($dotquad);
      $ipv6naddr = ipv6_aton($ipv6_text);
      $hex_text = ipv6_n2x($ipv6naddr);
      $dec_text = ipv6_n2d($ipv6naddr);
      $ipv6naddr = inet_any2n($dotquad or $ipv6_text);
      $rv = hasbits($bits128);
      $rv = isIPv4($bits128);
      $dotquad or $hex_text = inet_n2dx($ipv6naddr);
      $dotquad or $dec_text = inet_n2ad($ipv6naddr);
      $ipv6naddr = ipv4to6($netaddr);
      $ipv6naddr = mask4to6($netaddr);
      $ipv6naddr = ipanyto6($netaddr);
      $ipv6naddr = maskanyto6($netaddr);
      $netaddr = ipv6to4($pv6naddr);
      $bitsX2 = shiftleft($bits128,$n);
      $carry = addconst($ipv6naddr,$signed_32con);
      ($carry,$ipv6naddr)=addconst($ipv6naddr,$signed_32con);
      $carry = add128($ipv6naddr1,$ipv6naddr2);
      ($carry,$ipv6naddr)=add128($ipv6naddr1,$ipv6naddr2);
      $carry = sub128($ipv6naddr1,$ipv6naddr2);
      ($carry,$ipv6naddr)=sub128($ipv6naddr1,$ipv6naddr2);
      ($spurious,$cidr) = notcontiguous($mask128);
      $bcdtext = bin2bcd($bits128);
      $bits128 = bcd2bin($bcdtxt);
      $modetext = mode;

INSTALLATION
    Un-tar the distribution in an appropriate directory and type:

            perl Makefile.PL
            make
            make test
            make install

    NetAddr::IP::Util installs by default with its primary functions
    compiled using Perl's XS extensions to build a 'C' library. If you do
    not have a 'C' complier available or would like the slower Pure Perl
    version for some other reason, then type:

            perl Makefile.PL -noxs
            make
            make test
            make install

DESCRIPTION
    NetAddr::IP::Util provides a suite of tools for manipulating and
    converting IPv4 and IPv6 addresses into 128 bit string context and back
    to text. The strings can be manipulated with Perl's logical operators:

            and     &
            or      |
            xor     ^

    in the same manner as 'vec' strings.

    The IPv6 functions support all rfc1884 formats.

      i.e.  x:x:x:x:x:x:x:x:x
            x:x:x:x:x:x:x:d.d.d.d
            ::x:x:x
            ::x:d.d.d.d
      and so on...

    * $dotquad = inet_ntoa($netaddr);
        Convert a packed IPv4 network address to a dot-quad IP address.

          input:        packed network address
          returns:      IP address i.e. 10.4.12.123

    * $netaddr = inet_aton($dotquad);
        Convert a dot-quad IP address into an IPv4 packed network address.

          input:        IP address i.e. 192.5.16.32
          returns:      packed network address

    * $ipv6addr = ipv6_aton($ipv6_text);
        Takes an IPv6 address of the form described in rfc1884 and returns a
        128 bit binary RDATA string.

          input:        ipv6 text
          returns:      128 bit RDATA string

    * $hex_text = ipv6_n2x($ipv6addr);
        Takes an IPv6 RDATA string and returns an 8 segment IPv6 hex address

          input:        128 bit RDATA string
          returns:      x:x:x:x:x:x:x:x

    * $dec_text = ipv6_n2d($ipv6addr);
        Takes an IPv6 RDATA string and returns a mixed hex - decimal IPv6
        address with the 6 uppermost chunks in hex and the lower 32 bits in
        dot-quad representation.

          input:        128 bit RDATA string
          returns:      x:x:x:x:x:x:d.d.d.d

    * $ipv6naddr = inet_any2n($dotquad or $ipv6_text);
        This function converts a text IPv4 or IPv6 address in text format in
        any standard notation into a 128 bit IPv6 string address. It
        prefixes any dot-quad address (if found) with '::' and passes it to
        ipv6_aton.

          input:        dot-quad or rfc1844 address
          returns:      128 bit IPv6 string

    * $rv = hasbits($bits128);
        This function returns true if there are one's present in the 128 bit
        string and false if all the bits are zero.

          i.e.  if (hasbits($bits128)) {
                  &do_something;
                }

          or    if (hasbits($bits128 & $mask128) {
                  &do_something;
                }

        This allows the implementation of logical functions of the form of:

                if ($bits128 & $mask128) {
                    ...

          input:        128 bit IPv6 string
          returns:      true if any bits are present

    * $rv = isIPv4($bits128);
        This function returns true if there are no on bits present in the
        IPv6 portion of the 128 bit string and false otherwise.

    * $dotquad or $hex_text = inet_n2dx($ipv6naddr);
        This function does the right thing and returns the text for either a
        dot-quad IPv4 or a hex notation IPv6 address.

          input:        128 bit IPv6 string
          returns:      ddd.ddd.ddd.ddd
                    or  x:x:x:x:x:x:x:x

    * $dotquad or $dec_text = inet_n2ad($ipv6naddr);
        This function does the right thing and returns the text for either a
        dot-quad IPv4 or a hex::decimal notation IPv6 address.

          input:        128 bit IPv6 string
          returns:      ddd.ddd.ddd.ddd
                    or  x:x:x:x:x:x:ddd.ddd.ddd.dd

    * $ipv6naddr = ipv4to6($netaddr);
        Convert an ipv4 network address into an ipv6 network address.

          input:        32 bit network address
          returns:      128 bit network address

    * $ipv6naddr = mask4to6($netaddr);
        Convert an ipv4 network address/mask into an ipv6 network mask.

          input:        32 bit network/mask address
          returns:      128 bit network/mask address

        NOTE: returns the high 96 bits as one's

    * $ipv6naddr = ipanyto6($netaddr);
        Similar to ipv4to6 except that this function takes either an IPv4 or
        IPv6 input and always returns a 128 bit IPv6 network address.

          input:        32 or 128 bit network address
          returns:      128 bit network address

    * $ipv6naddr = maskanyto6($netaddr);
        Similar to mask4to6 except that this function takes either an IPv4
        or IPv6 netmask and always returns a 128 bit IPv6 netmask.

          input:        32 or 128 bit network mask
          returns:      128 bit network mask

    * $netaddr = ipv6to4($pv6naddr);
        Truncate the upper 96 bits of a 128 bit address and return the lower
        32 bits. Returns an IPv4 address as returned by inet_aton.

          input:        128 bit network address
          returns:      32 bit inet_aton network address

    * $bitsXn = shiftleft($bits128,$n);
          input:        128 bit string variable,
                        number of shifts [optional]
          returns:      bits X n shifts

          NOTE: a single shift is performed 
                if $n is not specified

    * addconst($ipv6naddr,$signed_32con);
        Add a signed constant to a 128 bit string variable.

          input:        128 bit IPv6 string,
                        signed 32 bit integer
          returns:  scalar      carry
                    array       (carry, result)

    * add128($ipv6naddr1,$ipv6naddr2);
        Add two 128 bit string variables.

          input:        128 bit string var1,
                        128 bit string var2
          returns:  scalar      carry
                    array       (carry, result)

    * sub128($ipv6naddr1,$ipv6naddr2);
        Subtract two 128 bit string variables.

          input:        128 bit string var1,
                        128 bit string var2
          returns:  scalar      carry
                    array       (carry, result)
    
        Note: The carry from this operation is the result of adding the
        one's complement of ARG2 +1 to the ARG1. It is logically NOT borrow.

                i.e.    if ARG1 >= ARG2 then carry = 1
                or      if ARG1  < ARG2 then carry = 0

    * ($spurious,$cidr) = notcontiguous($mask128);
        This function counts the bit positions remaining in the mask when
        the rightmost '0's are removed.

                input:  128 bit netmask
                returns true if there are spurious
                            zero bits remaining in the
                            mask, false if the mask is
                            contiguous one's,
                        128 bit cidr number

    * $bcdtext = bin2bcd($bits128);
        Convert a 128 bit binary string into binary coded decimal text
        digits.

          input:        128 bit string variable
          returns:      string of bcd text digits

    * $bits128 = bcd2bin($bcdtxt);
        Convert a bcd text string to 128 bit string variable

          input:        string of bcd text digits
          returns:      128 bit string variable

    * $modetext = mode;
        Returns the operating mode of this module.

                input:          none
                returns:        "Pure Perl"
                           or   "CC XS"

EXAMPLES
      # convert any textual IP address into a 128 bit vector
      #
      sub text2vec {
        my($anyIP,$anyMask) = @_;

      # not IPv4 bit mask
        my $notiv4 = ipv6_aton('FFFF:FFFF:FFFF:FFFF:FFFF:FFFF::');

        my $vecip   = inet_any2n($anyIP);
        my $mask    = inet_any2n($anyMask);

      # extend mask bits for IPv4
        my $bits = 128;     # default
        unless (hasbits($mask & $notiv4)) {
          $mask |= $notiv4;
          $bits = 32;
        }
        return ($vecip, $mask, $bits);
      }

      ... alternate implementation, a little faster

      sub text2vec {
        my($anyIP,$anyMask) = @_;

      # not IPv4 bit mask
        my $notiv4 = ipv6_aton('FFFF:FFFF:FFFF:FFFF:FFFF:FFFF::');

        my $vecip   = inet_any2n($anyIP);
        my $mask    = inet_any2n($anyMask);

      # extend mask bits for IPv4
        my $bits = 128;     # default
        if (isIPv4($mask)) {
          $mask |= $notiv4;
          $bits = 32;
        }
        return ($vecip, $mask, $bits);
      }

      ... elsewhere
        $nip = {
            addr    => $vecip,
            mask    => $mask,
            bits    => $bits,
        };

      # return network and broadcast addresses from IP and Mask
      #
      sub netbroad {
        my($nip) = shift;
        my $notmask = ~ $nip->{mask};
        my $bcast   = $nip->{addr} | $notmask;
        my $network = $nip->{addr} & $nip->{mask};
        return ($network, $broadcast);
      }

      # check if address is within a network
      #
      sub within {
        my($nip,$net) = @_;
        my $addr = $nip->{addr}
        my($nw,$bc) = netbroad($net);
      # arg1 >= arg2, sub128 returns true
        return (sub128($addr,$nw) && sub128($bc,$addr))
            ? 1 : 0;
      }

      # add a constant, wrapping at netblock boundries
      # to subtract the constant, negate it before calling 
      # 'addwrap' since 'addconst' will extend the sign bits
      #
      sub addwrap {
        my($nip,$const) = @_;
        my $mask    = $nip->{addr};
        my $bits    = $nip->{bits};
        my $notmask = ~ $mask;
        my $hibits  = $addr & $mask;
        my $addr = addconst($addr,$const);
        my $wraponly = $addr & $notmask;
        my $newip = {
            addr    => $hibits | $wraponly,
            mask    => $mask,
            bits    => $bits,
        };
        # bless $newip as appropriate
        return $newip;
      }     
    
EXPORT_OK
            inet_aton
            inet_ntoa
            ipv6_aton
            ipv6_n2x
            ipv6_n2d
            inet_any2n
            hasbits
            isIPv4
            inet_n2dx
            inet_n2ad
            ipv4to6
            mask4to6
            ipanyto6
            maskanyto6
            ipv6to4
            shiftleft
            addconst
            add128
            sub128
            notcontiguous
            bin2bcd
            bcd2bin
            mode

AUTHOR
    Michael Robinton <michael@bizsystems.com>

ACKNOWLEDGEMENTS
    The following functions are used in whole or in part as include files to
    Util.xs. The copyright is include in the file.

      file:              function:

      miniSocket.inc  inet_aton, inet_ntoa

    inet_aton, inet_ntoa are from the perl-5.8.0 release by Larry Wall,
    copyright 1989-2002. inet_aton, inet_ntoa code is current through
    perl-5.9.3 release. Thank you Larry for making PERL possible for all of
    us.

COPYRIGHT
    Copyright 2003 - 2008, Michael Robinton <michael@bizsystems.com>

    LICENSE AND WARRANTY

    This software is (c) Michael Robinton. It can be used under the terms of
    the perl artistic license provided that proper credit for the work of
    the author is preserved in the form of this copyright notice and license
    for this module.

    No warranty of any kind is expressed or implied, by using it you accept
    any and all the liability.

AUTHOR
    Michael Robinton <michael@bizsystems.com>