NetAddr-IP / Lite / README
@Michael Robinton Michael Robinton on 21 Oct 2014 19 KB Import of MIKER/NetAddr-IP-4.073 from CPAN.
    NetAddr::IP::Lite - Manages IPv4 and IPv6 addresses and subnets

      use NetAddr::IP::Lite qw(
            :aton           DEPRECATED !

      my $ip = new NetAddr::IP::Lite '';
            or if your prefer
      my $ip = NetAddr::IP::Lite->new(';
            or from a packed IPv4 address
      my $ip = new_from_aton NetAddr::IP::Lite (inet_aton(''));
            or from an octal filtered IPv4 address
      my $ip = new_no NetAddr::IP::Lite '';

      print "The address is ", $ip->addr, " with mask ", $ip->mask, "\n" ;

      if ($ip->within(new NetAddr::IP::Lite "", "")) {
          print "Is a loopback address\n";

                                    # This prints
      print "You can also say $ip...\n";

      The following four functions return ipV6 representations of:

      ::                                       = Zeros();
      FFFF:FFFF:FFFF:FFFF:FFFF:FFFF::          = V4mask();
      ::FFFF:FFFF                              = V4net();

      Will also return an ipV4 or ipV6 representation of a
      resolvable Fully Qualified Domanin Name (FQDN).

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

            perl Makefile.PL
            make test
            make install

    NetAddr::IP::Lite depends on NetAddr::IP::Util which 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 test
            make install

    This module provides an object-oriented abstraction on top of IP
    addresses or IP subnets, that allows for easy manipulations. Most of the
    operations of NetAddr::IP are supported. This module will work with
    older versions of Perl and is compatible with Math::BigInt.

    * By default NetAddr::IP functions and methods return string IPv6
    addresses in uppercase. To change that to lowercase:

    NOTE: the AUGUST 2010 RFC5952 states:

        4.3. Lowercase

          The characters "a", "b", "c", "d", "e", and "f" in an IPv6
          address MUST be represented in lowercase.

    It is recommended that all NEW applications using NetAddr::IP::Lite be
    invoked as shown on the next line.

      use NetAddr::IP::Lite qw(:lower);

    * To ensure the current IPv6 string case behavior even if the default

      use NetAddr::IP::Lite qw(:upper);

    The internal representation of all IP objects is in 128 bit IPv6
    notation. IPv4 and IPv6 objects may be freely mixed.

    The supported operations are described below:

  Overloaded Operators

    Assignment ("=")
        Has been optimized to copy one NetAddr::IP::Lite object to another
        very quickly.

        The assignment ("=") operation is only put in to operation when the
        copied object is further mutated by another overloaded operation.
        See the overload manpage SPECIAL SYMBOLS FOR "use overload" for

        "->copy()" actually creates a new object when called.

        An object can be used just as a string. For instance, the following

                my $ip = new NetAddr::IP::Lite '';
                print "$ip\n";

        Will print the string

                my $ip = new6 NetAddr::IP::Lite '';
                print "$ip\n";

        Will print the string 0:0:0:0:0:0:C0A8:17B/128

        You can test for equality with either "eq", "ne", "==" or "!=".
        "eq", "ne" allows the comparison with arbitrary strings as well as
        NetAddr::IP::Lite objects. The following example:

            if (NetAddr::IP::Lite->new('','') eq '')
               { print "Yes\n"; }

        Will print out "Yes".

        Comparison with "==" and "!=" requires both operands to be
        NetAddr::IP::Lite objects.

    Comparison via >, <, >=, <=, <=> and "cmp"
        Internally, all network objects are represented in 128 bit format.
        The numeric representation of the network is compared through the
        corresponding operation. Comparisons are tried first on the address
        portion of the object and if that is equal then the NUMERIC cidr
        portion of the masks are compared. This leads to the
        counterintuitive result that

                /24 > /16

        Comparison should not be done on netaddr objects with different CIDR
        as this may produce indeterminate - unexpected results, rather the
        determination of which netblock is larger or smaller should be done
        by comparing

                $ip1->masklen <=> $ip2->masklen

    Addition of a constant ("+")
        Add a 32 bit signed constant to the address part of a NetAddr
        object. This operation changes the address part to point so many
        hosts above the current objects start address. For instance, this

            print NetAddr::IP::Lite->new('') + 5;

        will output The address will wrap around at the
        broadcast back to the network address. This code:

            print NetAddr::IP::Lite->new('') + 255;


        Returns the the unchanged object when the constant is missing or out
        of range.

            2147483647 <= constant >= -2147483648

    Subtraction of a constant ("-")
        The complement of the addition of a constant.

    Difference ("-")
        Returns the difference between the address parts of two
        NetAddr::IP::Lite objects address parts as a 32 bit signed number.

        Returns undef if the difference is out of range.

        Auto-incrementing a NetAddr::IP::Lite object causes the address part
        to be adjusted to the next host address within the subnet. It will
        wrap at the broadcast address and start again from the network

        Auto-decrementing a NetAddr::IP::Lite object performs exactly the
        opposite of auto-incrementing it, as you would expect.


    "->new([$addr, [ $mask|IPv6 ]])"
    "->new6([$addr, [ $mask]])"
    "->new6FFFF([$addr, [ $mask]])"
    "->new_no([$addr, [ $mask]])"
    new_cis and new_cis6 are DEPRECATED
    "->new_cis("$addr $mask)"
    "->new_cis6("$addr $mask)"
        The first three methods create a new address with the supplied
        address in "$addr" and an optional netmask "$mask", which can be
        omitted to get a /32 or /128 netmask for IPv4 / IPv6 addresses

        new6FFFF specifically returns an IPv4 address in IPv6 format
        according to RFC4291

          new6               ::xxxx:xxxx
          new6FFFF      ::FFFF:xxxx:xxxx

        The third method "new_no" is exclusively for IPv4 addresses and
        filters improperly formatted dot quad strings for leading 0's that
        would normally be interpreted as octal format by NetAddr per the
        specifications for inet_aton.

        new_from_aton takes a packed IPv4 address and assumes a /32 mask.
        This function replaces the DEPRECATED :aton functionality which is
        fundamentally broken.

        The last two methods new_cis and new_cis6 differ from new and new6
        only in that they except the common Cisco address notation for
        address/mask pairs with a space as a separator instead of a slash

        These methods are DEPRECATED because the functionality is now
        included in the other "new" methods

          i.e.  ->new_cis(' 24')
                ->new_cis6(':: 120')

        "->new6" and "->new_cis6" mark the address as being in ipV6 address
        space even if the format would suggest otherwise.

          i.e.  ->new6('') will result in ::102:304

          addresses submitted to ->new in ipV6 notation will
          remain in that notation permanently. i.e.
                ->new('::') will result in ::102:304
          whereas new('') would print out as

          See "STRINGIFICATION" below.

        "$addr" can be almost anything that can be resolved to an IP address
        in all the notations I have seen over time. It can optionally
        contain the mask in CIDR notation. If the OPTIONAL perl module
        Socket6 is available in the local library it will autoload and ipV6
        host6 names will be resolved as well as ipV4 hostnames.

        prefix notation is understood, with the limitation that the range
        specified by the prefix must match with a valid subnet.

        Addresses in the same format returned by "inet_aton" or
        "gethostbyname" can also be understood, although no mask can be
        specified for them. The default is to not attempt to recognize this
        format, as it seems to be seldom used.

        ###### DEPRECATED, will be remove in version 5 ############ To
        accept addresses in that format, invoke the module as in

          use NetAddr::IP::Lite ':aton'

        ###### USE new_from_aton instead ##########################

        If called with no arguments, 'default' is assumed.

        If called with an empty string as the argument, returns 'undef'

        "$addr" can be any of the following and possibly more...

          n.n mm
          n.n.n mm
          n.n.n.n/mm            32 bit cidr notation
          n.n.n.n mm
          n.n.n.n m.m.m.m
          loopback, localhost, broadcast, any, default
          0xABCDEF, 0b111111000101011110, (or a bcd number)
          a netaddr as returned by 'inet_aton'

        Any RFC1884 notation

          ::n.n.n.n/mmm         128 bit cidr notation
          x:x:x:x:x:x:x:x/m:m:m:m:m:m:m:m any RFC1884 notation
          loopback, localhost, unspecified, any, default
          0xABCDEF, 0b111111000101011110 within the limits
          of perl's number resolution
          123456789012  a 'big' bcd number (bigger than perl likes)
          and Math::BigInt

        A Fully Qualified Domain Name which returns an ipV4 address or an
        ipV6 address, embodied in that order. This previously undocumented
        feature may be disabled with:

                use NetAddr::IP::Lite ':nofqdn';

        If called with no arguments, 'default' is assumed.

        If called with and empty string as the argument, 'undef' is

        Returns a new object referring to the broadcast address of a given
        subnet. The broadcast address has all ones in all the bit positions
        where the netmask has zero bits. This is normally used to address
        all the hosts in a given subnet.

        Returns a new object referring to the network address of a given
        subnet. A network address has all zero bits where the bits of the
        netmask are zero. Normally this is used to refer to a subnet.

        Returns a scalar with the address part of the object as an IPv4 or
        IPv6 text string as appropriate. This is useful for printing or for
        passing the address part of the NetAddr::IP::Lite object to other
        components that expect an IP address. If the object is an ipV6
        address or was created using ->new6($ip) it will be reported in ipV6
        hex format otherwise it will be reported in dot quad format only if
        it resides in ipV4 address space.

        Returns a scalar with the mask as an IPv4 or IPv6 text string as
        described above.

        Returns a scalar the number of one bits in the mask.

        Returns the width of the address in bits. Normally 32 for v4 and 128
        for v6.

        Returns the version of the address or subnet. Currently this can be
        either 4 or 6.

        Returns a scalar with the address and mask in CIDR notation. A
        NetAddr::IP::Lite object *stringifies* to the result of this
        function. (see comments about ->new6() and ->addr() for output

        Returns the address part of the NetAddr::IP::Lite object in the same
        format as the "inet_aton()" or "ipv6_aton" function respectively. If
        the object was created using ->new6($ip), the address returned will
        always be in ipV6 format, even for addresses in ipV4 address space.

        Returns a scalar with the base address and the broadcast address
        separated by a dash and spaces. This is called range notation.

        When called in a scalar context, will return a numeric
        representation of the address part of the IP address. When called in
        an array context, it returns a list of two elements. The first
        element is as described, the second element is the numeric
        representation of the netmask.

        This method is essential for serializing the representation of a

        When called in a scalar context, will return a Math::BigInt
        representation of the address part of the IP address. When called in
        an array contest, it returns a list of two elements. The first
        element is as described, the second element is the Math::BigInt
        representation of the netmask.

        Returns true when "$me" completely contains "$other". False is
        returned otherwise and "undef" is returned if "$me" and "$other" are
        not both "NetAddr::IP::Lite" objects.

        The complement of "->contains()". Returns true when "$me" is
        completely contained within "$other", undef if "$me" and "$other"
        are not both "NetAddr::IP::Lite" objects.

        Returns true when "$me" is an RFC 1918 address.

           -  (10/8 prefix)
         -  (172.16/12 prefix)
        - (192.168/16 prefix)

        Returns a new object representing the first usable IP address within
        the subnet (ie, the first host address).

        Returns a new object representing the last usable IP address within
        the subnet (ie, one less than the broadcast address).

        Returns a new object representing the *n*-th usable IP address
        within the subnet (ie, the *n*-th host address). If no address is
        available (for example, when the network is too small for "$index"
        hosts), "undef" is returned.

        Version 4.00 of NetAddr::IP and version 1.00 of NetAddr::IP::Lite
        implements "->nth($index)" and "->num()" exactly as the
        documentation states. Previous versions behaved slightly differently
        and not in a consistent manner.

        To use the old behavior for "->nth($index)" and "->num()":

          use NetAddr::IP::Lite qw(:old_nth);

          old behavior:
          NetAddr::IP->new('10/32')->nth(0) == undef
          NetAddr::IP->new('10/32')->nth(1) == undef
          NetAddr::IP->new('10/31')->nth(0) == undef
          NetAddr::IP->new('10/31')->nth(1) ==
          NetAddr::IP->new('10/30')->nth(0) == undef
          NetAddr::IP->new('10/30')->nth(1) ==
          NetAddr::IP->new('10/30')->nth(2) ==
          NetAddr::IP->new('10/30')->nth(3) ==

        Note that in each case, the broadcast address is represented in the
        output set and that the 'zero'th index is alway undef except for a
        point-to-point /31 or /127 network where there are exactly two
        addresses in the network.

          new behavior:
          NetAddr::IP->new('10/32')->nth(0)  ==
          NetAddr::IP->new('10.1/32'->nth(0) ==
          NetAddr::IP->new('10/31')->nth(0)  ==
          NetAddr::IP->new('10/31')->nth(1)  ==
          NetAddr::IP->new('10/30')->nth(0) ==
          NetAddr::IP->new('10/30')->nth(1) ==
          NetAddr::IP->new('10/30')->nth(2) == undef

        Note that a /32 net always has 1 usable address while a /31 has
        exactly two usable addresses for point-to-point addressing. The
        first index (0) returns the address immediately following the
        network address except for a /31 or /127 when it return the network

        As of version 4.42 of NetAddr::IP and version 1.27 of
        NetAddr::IP::Lite a /31 and /127 with return a net num value of 2
        instead of 0 (zero) for point-to-point networks.

        Version 4.00 of NetAddr::IP and version 1.00 of NetAddr::IP::Lite
        return the number of usable IP addresses within the subnet, not
        counting the broadcast or network address.

        Previous versions worked only for ipV4 addresses, returned a maximum
        span of 2**32 and returned the number of IP addresses not counting
        the broadcast address. (one greater than the new behavior)

        To use the old behavior for "->nth($index)" and "->num()":

          use NetAddr::IP::Lite qw(:old_nth);


        NetAddr::IP will calculate and return a numeric string for network
        ranges as large as 2**128. These values are TEXT strings and perl
        can treat them as integers for numeric calculations.

        Perl on 32 bit platforms only handles integer numbers up to 2**32
        and on 64 bit platforms to 2**64.

        If you wish to manipulate numeric strings returned by NetAddr::IP
        that are larger than 2**32 or 2**64, respectively, you must load
        additional modules such as Math::BigInt, bignum or some similar
        package to do the integer math.

            :aton           DEPRECATED

    Luis E. Muñoz <>, Michael Robinton

    This software comes with the same warranty as perl itself (ie, none), so
    by using it you accept any and all the liability.

     This software is (c) Luis E. Muñoz, 1999 - 2005
     and (c) Michael Robinton, 2006 - 2014.

    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
    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

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

    or visit their web page on the internet at:


    NetAddr::IP(3), NetAddr::IP::Util(3), NetAddr::IP::InetBase(3)