NetAddr-IP / Lite /
@Luis Muñoz Luis Muñoz authored on 2 Aug 2006
Gitpan committed on 21 Oct 2014
..
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README
NAME
    NetAddr::IP::Lite - Manages IPv4 and IPv6 addresses and subnets

SYNOPSIS
      use NetAddr::IP::Lite qw(
            Zeros
            Ones
            V4mask
            V4net
            :aton
            :old_nth
      );

      my $ip = new NetAddr::IP::Lite '127.0.0.1';

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

      if ($ip->within(new NetAddr::IP::Lite "127.0.0.0", "255.0.0.0")) {
          print "Is a loopback address\n";
      }

                                    # This prints 127.0.0.1/32
      print "You can also say $ip...\n";

      The following four functions return ipV6 representations of:

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

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

            perl Makefile.PL
            make
            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
            make test
            make install

DESCRIPTION
    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 older
    versions of Perl and does not use Math::BigInt.

    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.

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

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

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

                my $ip = new NetAddr::IP::Lite '192.168.1.123';
                print "$ip\n";

        Will print the string 192.168.1.123/32.

                my $ip = new6 NetAddr::IP::Lite '192.168.1.123';
                print "$ip\n";

        Will print the string

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

            if (NetAddr::IP::Lite->new('127.0.0.1','255.0.0.0') eq '127.0.0.1/8') 
               { print "Yes\n"; }

        Will print out "Yes".

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

        In both cases, a true value is returned if the CIDR representation
        of the operands is equal.

    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 cidr portion of
        the masks are compared.

    Addition of a constant
        Adding a constant to a NetAddr::IP::Lite object changes its address
        part to point to the one so many hosts above the start address. For
        instance, this code:

            print NetAddr::IP::Lite->new('127.0.0.1') + 5;

        will output 127.0.0.6/8. The address will wrap around at the
        broadcast back to the network address. This code:

            print NetAddr::IP::Lite->new('10.0.0.1/24') + 255;

        outputs 10.0.0.0/24.

    Substraction of a constant
        The complement of the addition of a constant.

    Auto-increment
        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
        address.

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

  Methods
    "->new([$addr, [ $mask|IPv6 ]])"
    "->new6([$addr, [ $mask]])"
        These methods creates 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 respectively

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

          i.e.  ->new6('1.2.3.4') will result in ::102:304

          addresses submitted to ->new in ipV6 notation will
          remain in that notation permanently. i.e.
                ->new('::1.2.3.4') will result in ::102:304
          whereas new('1.2.3.4') would print out as 1.2.3.4

          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.

        prefix notation is understood, with the limitation that the range
        speficied 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.

        To accept addresses in that format, invoke the module as in

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

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

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

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

        Any RFC1884 notation

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

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

    "->broadcast()"
        Returns a new object refering 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.

    "->network()"
        Returns a new object refering 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.

    "->addr()"
        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.

    "->mask()"
        Returns a scalar with the mask as an IPv4 or IPv6 text string as
        described above.

    "->masklen()"
        Returns a scalar the number of one bits in the mask.

    "->bits()"
        Returns the width of the address in bits. Normally 32 for v4 and 128
        for v6.

    "->version()"
        Returns the version of the address or subnet. Currently this can be
        either 4 or 6.

    "->cidr()"
        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
        formats)

    "->aton()"
        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.

    "->range()"
        Returns a scalar with the base address and the broadcast address
        separated by a dash and spaces. This is called range notation.

    "->numeric()"
        When called in a scalar context, will return a numeric
        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 numeric
        representation of the netmask.

        This method is essential for serializing the representation of a
        subnet.

    "$me->contains($other)"
        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.

    "$me->within($other)"
        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.

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

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

    "->nth($index)"
        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) == 10.0.0.1/31
          NetAddr::IP->new('10/30')->nth(0) == undef  
          NetAddr::IP->new('10/30')->nth(1) == 10.0.0.1/30
          NetAddr::IP->new('10/30')->nth(2) == 10.0.0.2/30
          NetAddr::IP->new('10/30')->nth(3) == 10.0.0.3/30

        Note that in each case, the broadcast address is represented in the
        output set and that the 'zero'th index is alway undef.

          new behavior:
          NetAddr::IP->new('10/32')->nth(0)  == 10.0.0.0/32
          NetAddr::IP->new('10.1/32'->nth(0) == 10.0.0.1/32
          NetAddr::IP->new('10/31')->nth(0)  == undef  
          NetAddr::IP->new('10/31')->nth(1)  == undef
          NetAddr::IP->new('10/30')->nth(0) == 10.0.0.1/30
          NetAddr::IP->new('10/30')->nth(1) == 10.0.0.2/30
          NetAddr::IP->new('10/30')->nth(2) == undef

        Note that a /32 net always has 1 usable address while a /31 has none
        since it has a network and broadcast address, but no host addresses.
        The first index (0) returns the address immediately following the
        network address.

    "->num()"
        Version 4.00 of NetAddr::IP and version 1.00 of NetAddr::IP::Lite
        Returns the number of usable addresses IP addresses within the
        subnet, not counting the broadcast or network address. Previous
        versions returned th number of IP addresses not counting the
        broadcast address.

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

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

EXPORT_OK
            Zero
            Ones
            V4mask
            V4net
            :aton
            :old_nth

AUTHOR
    Luis E. Muñoz <luismunoz@cpan.org>, Michael Robinton
    <michael@bizsystems.com>

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

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

SEE ALSO
    perl(1), NetAddr::IP(3), NetAddr::IP::Util(3)