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

SYNOPSIS
      use NetAddr::IP::Util qw(
            inet_aton
            inet_ntoa
            ipv6_aton
            ipv6_ntoa
            ipv6_n2x
            ipv6_n2d
            inet_any2n
            hasbits
            isIPv4
            isNewIPv4
            isAnyIPv4
            inet_n2dx
            inet_n2ad
            inet_pton
            inet_ntop
            inet_4map6
            ipv4to6
            mask4to6
            ipanyto6
            maskanyto6
            ipv6to4
            packzeros
            shiftleft
            addconst
            add128
            sub128
            notcontiguous
            bin2bcd
            bcd2bin
            mode
            AF_INET
            AF_INET6
            naip_gethostbyname
      );

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

      :inet   =>    inet_aton, inet_ntoa, ipv6_aton
                    ipv6_ntoa, ipv6_n2x, ipv6_n2d, 
                    inet_any2n, inet_n2dx, inet_n2ad, 
                    inet_pton, inet_ntop, inet_4map6, 
                    ipv4to6, mask4to6, ipanyto6, packzeros
                    maskanyto6, ipv6to4, naip_gethostbyname

      :ipv4   =>    inet_aton, inet_ntoa

      :ipv6   =>    ipv6_aton, ipv6_ntoa, ipv6_n2x, 
                    ipv6_n2d, inet_any2n, inet_n2dx, 
                    inet_n2ad, inet_pton, inet_ntop,
                    inet_4map6, ipv4to6, mask4to6,
                    ipanyto6, maskanyto6, ipv6to4,
                    packzeros, naip_gethostbyname

      :math   =>    hasbits, isIPv4, isNewIPv4, isAnyIPv4,
                    addconst, add128, sub128, notcontiguous,
                    bin2bcd, bcd2bin, shiftleft

      $dotquad = inet_ntoa($netaddr);
      $netaddr = inet_aton($dotquad);
      $ipv6naddr = ipv6_aton($ipv6_text);
      $ipv6_text = ipvt_ntoa($ipv6naddr);
      $hex_text = ipv6_n2x($ipv6naddr);
      $dec_text = ipv6_n2d($ipv6naddr);
      $hex_text = packzeros($hex_text);
      $ipv6naddr = inet_any2n($dotquad or $ipv6_text);
      $ipv6naddr = inet_4map6($netaddr or $ipv6naddr);
      $rv = hasbits($bits128);
      $rv = isIPv4($bits128);
      $rv = isNewIPv4($bits128);
      $rv = isAnyIPv4($bits128);
      $dotquad or $hex_text = inet_n2dx($ipv6naddr);
      $dotquad or $dec_text = inet_n2ad($ipv6naddr);
      $netaddr = inet_pton($AF_family,$hex_text);
      $hex_text = inet_ntop($AF_family,$netaddr);
      $ipv6naddr = ipv4to6($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);
      $modetext = mode;
      ($name,$aliases,$addrtype,$length,@addrs)=naip_gethostbyname(NAME);
      $trueif = havegethostbyname2();

      NetAddr::IP::Util::lower();
      NetAddr::IP::Util::upper();

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     ^
                    ~       compliment

    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

    * $ipv6_text = ipv6_ntoa($ipv6naddr);
        Convert a 128 bit binary IPv6 address to compressed rfc 1884 text
        representation.

          input:        128 bit RDATA string
          returns:      ipv6 text

    * $hex_text = ipv6_n2x($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

    * $ipv6naddr = inet_4map6($netaddr or $ipv6naddr
        This function returns an ipV6 network address with the first 80 bits
        set to zero and the next 16 bits set to one, while the last 32 bits
        are filled with the ipV4 address.

          input:        ipV4 netaddr
                    or  ipV6 netaddr
          returns:      ipV6 netaddr

          returns: undef on error

        An ipV6 network address must be in one of the two compatible ipV4
        mapped address spaces. i.e.

                ::ffff::d.d.d.d    or    ::d.d.d.d

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

          i.e.  the address must be of the form - ::d.d.d.d

        Note: this is an old and deprecated ipV4 compatible ipV6 address

    * $rv = isNewIPv4($bits128);
        This function return true if the IPv6 128 bit string is of the form

                ::ffff::d.d.d.d

    * $rv = isAnyIPv4($bits128);
        This function return true if the IPv6 bit string is of the form

                ::d.d.d.d       or      ::ffff::d.d.d.d

    * $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

    * $netaddr = inet_pton($AF_family,$hex_text);
        This function takes an IP address in IPv4 or IPv6 text format and
        converts it into binary format. The type of IP address conversion is
        controlled by the FAMILY argument.

    * $hex_text = inet_ntop($AF_family,$netaddr);
        This function takes and IP address in binary format and converts it
        into text format. The type of IP address conversion is controlled by
        the FAMILY argument.

        NOTE: inet_ntop ALWAYS returns lowercase characters.

    * $hex_text = packzeros($hex_text);
        This function optimizes and rfc 1884 IPv6 hex address to reduce the
        number of long strings of zero bits as specified in rfc 1884, 2.2
        (2) by substituting :: for the first occurence of the longest string
        of zeros in the address.

    * $ipv6naddr = ipv4to6($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"

    * ($name,$aliases,$addrtype,$length,@addrs)=naip_gethostbyname(NAME);
        Replacement for Perl's gethostbyname if Socket6 is available

        In ARRAY context, returns a list of five elements, the hostname or
        NAME, a space separated list of C_NAMES, AF family, length of the
        address structure, and an array of one or more netaddr's

        In SCALAR context, returns the first netaddr.

        This function ALWAYS returns an IPv6 address, even on IPv4 only
        systems. IPv4 addresses are mapped into IPv6 space in the form:

                ::FFFF:FFFF:d.d.d.d

        This is NOT the expected result from Perl's gethostbyname2. It is
        instead equivalent to:

          On an IPv4 only system:
            $ipv6naddr = ipv4to6 scalar ( gethostbyname( name ));

          On a system with Socket6 and a working gethostbyname2:
            $ipv6naddr = gethostbyname2( name, AF_INET6 );
          and if that fails, the IPv4 conversion above.

        For a gethostbyname2 emulator that behave like Socket6, see: the
        Net::DNS::Dig manpage

    * $trueif = havegethostbyname2();
        This function returns TRUE if Socket6 has a functioning
        gethostbyname2, otherwise it returns FALSE. See the comments above
        about the behavior of naip_gethostbyname.

    * NetAddr::IP::Util::lower();
        Return IPv6 strings in lowercase.

    * NetAddr::IP::Util::upper();
        Return IPv6 strings in uppercase. This is the default.

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;
      }

      # truely hard way to do $ip++
      # add a constant, wrapping at netblock boundaries
      # to subtract the constant, negate it before calling
      # 'addwrap' since 'addconst' will extend the sign bits
      #
      sub addwrap {
        my($nip,$const) = @_;
        my $addr    = $nip->{addr};
        my $mask    = $nip->{mask};
        my $bits    = $nip->{bits};
        my $notmask = ~ $mask;
        my $hibits  = $addr & $mask;
        $addr = addconst($addr,$const);
        my $wraponly = $addr & $notmask;
        my $newip = {
            addr    => $hibits | $wraponly,
            mask    => $mask,
            bits    => $bits,
        };
        # bless $newip as appropriate
        return $newip;
      }

      # something more useful
      # increment a /24 net to the NEXT net at the boundry

      my $nextnet = 256;    # for /24
      LOOP:
      while (...continuing) {
        your code....
        ...
        my $lastip = $ip-copy();
        $ip++;
        if ($ip < $lastip) {        # host part wrapped?
      # discard carry
          (undef, $ip->{addr} = addconst($ip->{addr}, $nextnet);
        }
        next LOOP;
      }

EXPORT_OK
            inet_aton
            inet_ntoa
            ipv6_aton
            ipv6_ntoa
            ipv6_n2x
            ipv6_n2d
            inet_any2n
            hasbits
            isIPv4
            isNewIPv4
            isAnyIPv4
            inet_n2dx
            inet_n2ad
            inet_pton
            inet_ntop
            inet_4map6
            ipv4to6
            mask4to6
            ipanyto6
            maskanyto6
            ipv6to4
            packzeros
            shiftleft
            addconst
            add128
            sub128
            notcontiguous
            bin2bcd
            bcd2bin
            mode
            naip_gethostbyname
            havegethostbyname2

AUTHOR
    Michael Robinton <michael@bizsystems.com>

COPYRIGHT
    Copyright 2003 - 2014, Michael Robinton <michael@bizsystems.com>

    All rights reserved.

    This program is free software; you can redistribute it and/or modify it
    under the terms of either:

      a) the GNU General Public License as published by the Free
      Software Foundation; either version 2, or (at your option) any
      later version, or

      b) the "Artistic License" which comes with this distribution.

    This program is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See either the GNU
    General Public License or the Artistic License for more details.

    You should have received a copy of the Artistic License with this
    distribution, in the file named "Artistic". If not, I'll be glad to
    provide one.

    You should also have received a copy of the GNU General Public License
    along with this program in the file named "Copying". If not, write to
    the

            Free Software Foundation, Inc.
            51 Franklin Street, Fifth Floor
            Boston, MA 02110-1301 USA.

    or visit their web page on the internet at:

            http://www.gnu.org/copyleft/gpl.html.

AUTHOR
    Michael Robinton <michael@bizsystems.com>

SEE ALSO
    NetAddr::IP(3), NetAddr::IP::Lite(3), NetAddr::IP::InetBase(3)