Content-type: text/html Man page of IP

IP

Section: User Contributed Perl Documentation (3pm)
Updated: 2009-01-26
Index Return to Main Contents
 

NAME

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

SYNOPSIS

  use NetAddr::IP qw(
        Compact
        Coalesce
        Zeros
        Ones
        V4mask
        V4net
        netlimit
        :aton           DEPRECATED
        :lower
        :upper
        :old_storable
        :old_nth
  );

  NOTE: NetAddr::IP::Util has a full complement of network address
        utilites to convert back and from from binary to text.

        inet_aton, inet_ntoa, ipv6_aton, ipv6_n2x, ipv6_n2d
        inet_any2d, inet_n2dx, inet_n2ad, inetanyto6, ipv6to4

See NetAddr::IP::Util

  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 "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();

###### DEPRECATED, will be remove in version 5 ############

  * To accept addresses in the format as returned by
  inet_aton, invoke the module as:

  use NetAddr::IP qw(:aton);

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

* To enable usage of legacy data files containing NetAddr::IP objects stored using the Storable module.

  use NetAddr::IP qw(:old_storable);

* To compact many smaller subnets (see: "$me->compact($addr1,$addr2,...)"

  @compacted_object_list = Compact(@object_list)

* Return a reference to list of "NetAddr::IP" subnets of $masklen mask length, when $number or more addresses from @list_of_subnets are found to be contained in said subnet.

  $arrayref = Coalesce($masklen, $number, @list_of_subnets)

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

  use NetAddr::IP qw(:lower);

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

  use NetAddr::IP qw(:upper);

* To set a limit on the size of nets processed or returned by NetAddr::IP. Set the maximum number of nets beyond which NetAddr::IP will return and error as a power of 2 (default 16 or 65536 nets). Each 2**16 consumes approximately 4 megs of memory. A 2**20 consumes 64 megs of memory, A 2**24 consumes 1 gigabyte of memory.

  use NetAddr::IP qw(netlimit);
  netlimit 20;

The maximum netlimit allowed is a 2**24. Attempts to set limits below the default of 16 or above the maximum of 24 are ignored.

Returns true on success otherwise undef.  

INSTALLATION

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

        perl Makefile.PL
        make
        make test
        make install

NetAddr::IP 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. Version 4.xx of NetAdder::IP will will work older versions of Perl and does not use Math::BigInt as in previous versions.

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

Overloaded Operators

Many operators have been overloaded, as described below:
Assignment ("=")
Has been optimized to copy one NetAddr::IP 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 $ip = new NetAddr::IP '192.168.1.123';
        print "$ip\n";

Will print the string 192.168.1.123/32.

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

    if (NetAddr::IP->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 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.

(See range restrictions on Addition above)

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

Serializing and Deserializing

This module defines hooks to collaborate with Storable for serializing "NetAddr::IP" objects, through compact and human readable strings. You can revert to the old format by invoking this module as

  use NetAddr::IP ':old_storable';

You must do this if you have legacy data files containing NetAddr::IP objects stored using the Storable module.  

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

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 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.

"->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.

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

  use NetAddr::IP ':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 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 object to other components that expect an IP address. If the object is an ipV6 address or was created using ->new6($ip) it will be reported in ipV6 hex format otherwise it will be reported in dot quad format only if it resides in ipV4 address space.
"->mask()"
Returns a scalar with the mask as an IPv4 or IPv6 text string as described above.
"->masklen()"
Returns a scalar the number of one bits in the mask.
"->bits()"
Returns the width of the address in bits. Normally 32 for v4 and 128 for v6.
"->version()"
Returns the version of the address or subnet. Currently this can be either 4 or 6.
"->cidr()"
Returns a scalar with the address and mask in CIDR notation. A NetAddr::IP object stringifies to the result of this function. (see comments about ->new6() and ->addr() for output formats)
"->aton()"
Returns the address part of the NetAddr::IP object in the same format as the "inet_aton()" or "ipv6_aton" function respectively. If the object was created using ->new6($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.
"->prefix()"
Returns a scalar with the address and mask in ipV4 prefix representation. This is useful for some programs, which expect its input to be in this format. This method will include the broadcast address in the encoding.
"->nprefix()"
Just as "->prefix()", but does not include the broadcast address.
"->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.

"->wildcard()"
When called in a scalar context, returns the wildcard bits corresponding to the mask, in dotted-quad or ipV6 format as applicable.

When called in an array context, returns a two-element array. The first element, is the address part. The second element, is the wildcard translation of the mask.

"->short()"
Returns the address part in a short or compact notation.

  (ie, 127.0.0.1 becomes 127.1).

Works with both, V4 and V6.

"->full()"
Returns the address part in FULL notation for ipV4 and ipV6 respectively.

  i.e. for ipV4
    0000:0000:0000:0000:0000:0000:127.0.0.1

       for ipV6
    0000:0000:0000:0000:0000:0000:0000:0000

To force ipV4 addresses into full ipV6 format use:

"->full6()"
Returns the address part in FULL ipV6 notation
"$me->contains($other)"
Returns true when $me completely contains $other. False is returned otherwise and "undef" is returned if $me and $other are not both "NetAddr::IP" objects.
"$me->within($other)"
The complement of "->contains()". Returns true when $me is completely contained within $other.

Note that $me and $other must be "NetAddr::IP" objects.

"->splitref($bits,[optional $bits1,$bits2,...])"
Returns a reference to a list of objects, representing subnets of "bits" mask produced by splitting the original object, which is left unchanged. Note that $bits must be longer than the original mask in order for it to be splittable.

ERROR conditions:

  ->splitref will DIE with the message 'netlimit exceeded'
    if the number of return objects exceeds 'netlimit'.
    See function 'netlimit' above (default 2**16 or 65536 nets).

  ->splitref returns undef when C<bits> or the (bits list)
    will not fit within the original object.

  ->splitref returns undef if a supplied ipV4, ipV6, or NetAddr
    mask in inappropriately formatted,

bits may be a CIDR mask, a dot quad or ipV6 string or a NetAddr::IP object. If "bits" is missing, the object is split for into all available addresses within the ipV4 or ipV6 object ( auto-mask of CIDR 32, 128 respectively ).

With optional additional "bits" list, the original object is split into parts sized based on the list. NOTE: a short list will replicate the last item. If the last item is too large to for what remains of the object after splitting off the first parts of the list, a ``best fits'' list of remaining objects will be returned based on an increasing sort of the CIDR values of the "bits" list.

  i.e.  my $ip = new NetAddr::IP('192.168.0.0');
        my $objptr = $ip->split(28, 29, 28, 29, 26);

   has split plan 28 29 28 29 26 26 26 28
   and returns this list of objects

        192.168.0.0/28
        192.168.0.16/29
        192.168.0.24/28
        192.168.0.40/29
        192.168.0.48/26
        192.168.0.112/26
        192.168.0.176/26
        192.168.0.240/28

NOTE: that /26 replicates twice beyond the original request and /28 fills the remaining return object requirement.

"->rsplitref($bits,[optional $bits1,$bits2,...])"
"->rsplitref" is the same as "->splitref" above except that the split plan is applied to the original object in reverse order.

  i.e.  my $ip = new NetAddr::IP('192.168.0.0');
        my @objects = $ip->split(28, 29, 28, 29, 26);

   has split plan 28 26 26 26 29 28 29 28
   and returns this list of objects

        192.168.0.0/28
        192.168.0.16/26
        192.168.0.80/26
        192.168.0.144/26
        192.168.0.208/29
        192.168.0.216/28
        192.168.0.232/29
        192.168.0.240/28

"->split($bits,[optional $bits1,$bits2,...])"
Similar to "->splitref" above but returns the list rather than a list reference. You may not want to use this if a large number of objects is expected.
"->rsplit($bits,[optional $bits1,$bits2,...])"
Similar to "->rsplitref" above but returns the list rather than a list reference. You may not want to use this if a large number of objects is expected.
"->hostenum()"
Returns the list of hosts within a subnet.

ERROR conditions:

  ->hostenum will DIE with the message 'netlimit exceeded'
    if the number of return objects exceeds 'netlimit'.
    See function 'netlimit' above (default 2**16 or 65536 nets).

"->hostenumref()"
Faster version of "->hostenum()", returning a reference to a list.
"$me->compact($addr1, $addr2, ...)"
"@compacted_object_list = Compact(@object_list)"
Given a list of objects (including $me), this method will compact all the addresses and subnets into the largest (ie, least specific) subnets possible that contain exactly all of the given objects.

Note that in versions prior to 3.02, if fed with the same IP subnets multiple times, these subnets would be returned. From 3.02 on, a more ``correct'' approach has been adopted and only one address would be returned.

Note that $me and all $addr's must be "NetAddr::IP" objects.

"$me->compactref(\@list)"
As usual, a faster version of =item "->compact()" that returns a reference to a list. Note that this method takes a reference to a list instead.

Note that $me must be a "NetAddr::IP" object.

"$me->coalesce($masklen, $number, @list_of_subnets)"
"$arrayref = Coalesce($masklen,$number,@list_of_subnets)"
Will return a reference to list of "NetAddr::IP" subnets of $masklen mask length, when $number or more addresses from @list_of_subnets are found to be contained in said subnet.

Subnets from @list_of_subnets with a mask shorter than $masklen are passed ``as is'' to the return list.

Subnets from @list_of_subnets with a mask longer than $masklen will be counted (actually, the number of IP addresses is counted) towards $number.

Called as a method, the array will include $me.

WARNING: the list of subnet must be the same type. i.e ipV4 or ipV6

"->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. See the README file for details.

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

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

"->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);

"->re()"
Returns a Perl regular expression that will match an IP address within the given subnet. Defaults to ipV4 notation. Will return an ipV6 regex if the address in not in ipV4 space.
"->re6()"
Returns a Perl regular expression that will match an IP address within the given subnet. Always returns an ipV6 regex.
 

EXPORT_OK

        Compact
        Coalesce
        Zeros
        Ones
        V4mask
        V4net
        netlimit

 

NOTES / BUGS ... FEATURES

NetAddr::IP only runs in Pure Perl mode on Windows boxes because I don't have the resources or know how to get the ``configure'' stuff working in the Windows environment. Volunteers WELCOME to port the ``C'' portion of this module to Windows.  

HISTORY

4.00
Dependence on Math::BigInt in earlier version is removed in this release 4.00. NetAddr::IP now works with earlier versions of Perl. The module was partitioned into three logical pieces as follows:

Util.pm              Math and logic operation on bit strings and number
                that represent IP addresses and masks. Conversions
                between various number formats. Implemented in
                C_XS for speed and PURE PERL of transportability.

Lite.pm              Operations, simple conversions and comparisons of
                IP addresses, notations and formats.

IP.pm                Complex operations and conversions of IP address
                notation, nets, subnets, and ranges.

The internal representation of addresses was changed to 128 bit binary strings as returned by inet_pton (ipv6_aton in this module). Both ipV4 and ipV6 notations can be freely mixed and matched.

Additional methods added to force operations into ipV6 space even when ipV4 notation is used.

4.05
        NetAddr::IP :aton       DEPRECATED !
        new method "new_from_aton"

THE FOLLOWING CHANGES MAY BREAK SOME CODE !

      Inherited methods from Lite.pm updated as follows:

        comparisons of the form <, >, <=, >=

                10.0.0.0/24 {operator} 10.0.0.0/16

        return now return the comparison of the cidr value
        when the address portion is equal.
        Thanks to Peter DeVries for spotting this bug.

        ... and leading us to discover that this next fix is required

        comparisons of the form <=>, cmp
        now return the correct value 1, or -1
        when the address portion is equal and the CIDR value is not
        i.e.    where /16 is > /24, etc...

        This is the OPPOSITE of the previous return values for
        comparison of the CIDR portion of the address object

4.08
        added method ->new_from_aton to supplement broken
        :aton functionality which is now DEPRECATED and
        will eventually go away.

4.13
        added 'no octal' method ->new_no

4.17
        add support for PTHREADS in the event that perl is
        built with <pthreads.h>. This must be invoked at build
        time with the switch --with-threads

        WARNING: --with-threads is not tested in a threads
        environment. Reports welcome and solicited.

        update _compV6 which runs faster and produces more
        compact ipV6 addresses.
        ....and
        added minus (-) overloading to allow the subtraction
        of two NetAddr::IP objects to get the difference between
        the object->{addr}'s as a numeric value

        Thanks to Rob Riepel <[email protected]> for
        the _compV6 code and the inspiration for (-) overloading.

        Extended the capability of 'splitref' to allow splitting of
        objects into multiple pieces with differing CIDR masks.
        Returned object list can be split from bottom to top
        or from top to bottom depending on which routine is called

                split, rsplit, splitref, rsplitref

        Thanks to kashmish <[email protected]> for the idea on
        improving functionality of 'split'.

4.018
        removed --with-threads, PTHREADS support, and all
        the mutex locking - unlocking

        updated Util.xs to be fully re-entrant and thus
        fully thread safe.

4.020
        Fixed core dump due to bug in perl 5.8.4 handling of
        @_ in goto &sub operations. Unfortunately this version
        of perl is standard on Solaris, 5.85 on RedHat and I'm
        sure other distributions. -- all should be upgraded!
        Similar behavior exists in perl versions 5.80 - 5.85
        See perl bug [ 23429].

        Included missing code to parse BCD numbers as argument
        to sub new(bcdnum). Thanks to Carlos Vicente [email protected]
        for reporting this bug.

 

AUTHORS

Luis E. MuA~Xoz <[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. MuA~Xoz, 1999 - 2007, 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 authors is preserved in the form of this copyright notice and license for this module.  

SEE ALSO

  perl(1),NetAddr::IP::Lite, NetAddr::IP::Util.


 

Index

NAME
SYNOPSIS
INSTALLATION
DESCRIPTION
Overloaded Operators
Serializing and Deserializing
Methods
EXPORT_OK
NOTES / BUGS ... FEATURES
HISTORY
AUTHORS
WARRANTY
LICENSE
SEE ALSO

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