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Lite

Section: User Contributed Perl Documentation (3pm)
Updated: 2008-12-10
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NAME

NetAddr::IP::Lite - Manages IPv4 and IPv6 addresses and subnets  

SYNOPSIS

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

  my $ip = new NetAddr::IP::Lite '127.0.0.1';
        or from a packed IPv4 address
  my $ip = new_from_aton NetAddr::IP::Lite (inet_aton('127.0.0.1'));
        or from an octal filtered IPv4 address
  my $ip = new_no NetAddr::IP::Lite '127.012.0.0';

  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 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 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.

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-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, [ $mask]])"
"->new_no([$addr, [ $mask]])"
"->new_from_aton($netaddr)"
The first two 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 respectively.

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.

"->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 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.

$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, (or 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 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.
"->network()"
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.
"->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

        Zeros
        Ones
        V4mask
        V4net
        :aton           DEPRECATED
        :old_nth

 

AUTHOR

Luis E. Mun~oz <[email protected]>, Michael Robinton <[email protected]>  

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. Mun~oz, 1999 - 2005
 and (c) Michael Robinton, 2006 - 2008.

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)


 

Index

NAME
SYNOPSIS
INSTALLATION
DESCRIPTION
Overloaded Operators
Methods
EXPORT_OK
AUTHOR
WARRANTY
LICENSE
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 04:14:17 GMT, September 24, 2010