
=encoding UTF-8

=head1 NAME

Net::IPv6Addr - Check validity of IPv6 addresses

=head1 VERSION

This documents version 0.91 of Net::IPv6Addr corresponding to
L<git commit c2d4788cdfc81b2f08562860e4cfe0a2373a35c2|https://github.com/benkasminbullock/net-ipv6addr/commit/c2d4788cdfc81b2f08562860e4cfe0a2373a35c2> released on Fri Oct 6 12:00:28 2017 +0900.

=head1 SYNOPSIS

    
    use Net::IPv6Addr;
    my $addr = "dead:beef:cafe:babe::f0ad";
    Net::IPv6Addr::ipv6_parse($addr);
    my $x = Net::IPv6Addr->new($addr);
    print $x->to_string_preferred(), "\n";


produces output

    dead:beef:cafe:babe:0:0:0:f0ad


(This example is included as L<F<synopsis.pl>|https://api.metacpan.org/source/BKB/Net-IPv6Addr-0.91/examples/synopsis.pl> in the distribution.)


=head1 DESCRIPTION

C<Net::IPv6Addr> checks strings for valid IPv6 addresses, as specified
in L<RFC1884|/RFCs>, and converts addresses into various formats. It
is able to process addresses formatted in the following styles;

=over

=item preferred form: x:x:x:x:x:x:x:x

=item zero-compressed form: the infamous double-colon.  

Too many pattern matches to describe in this margin.

=item	mixed IPv4/IPv6 format: x:x:x:x:x:x:d.d.d.d

=item	mixed IPv4/IPv6 with compression: ::d.d.d.d or ::FFFF:d.d.d.d

=item	base-85-encoded: [0-9A-Za-z!#$%&()*+;<=>?@^_`{|}~-]{20}

(This encoding was given in L<RFC1924|/RFCs> as an April Fool's joke.)

=back

=head1 METHODS AND FUNCTIONS

Several of the following serve as both object methods and standalone
functions.

=head2 new

    my $ni = Net::IPv6Addr->new ('dead:beef:cafe:babe::f0ad');

Create a new Net::IPv6Addr object from a string. Internally, the
object is a blessed array reference containing the eight parts of the
address as integers.

=head3 Parameters

A string to be interpreted as an IPv6 address.

=head3 Returns

A C<Net::IPv6Addr> object if successful.

=head3 Notes

Throws an exception if the string isn't a valid address.

=head2 ipv6_parse

    my ($ni, $pl) = ipv6_parse ('dead:beef:cafe:babe::f0ad');

=head3 Parameters

Either a string containing an IPv6 address string, which may also
include a C</> character and a numeric prefix length,

    my ($x, $y) = ipv6_parse ("a::/24");

or an IPv6 address string, with an optional second argument consisting
of a numeric prefix length:

    my ($x, $y) = ipv6_parse('a::', '24');

=head3 Returns

Called in array context, the return value is a list consisting of the
address string and the prefix, if it parses correctly. Called in
scalar context, the address and prefix are concatenated with "/".

=head3 Notes

Throws an exception on malformed input.

=head2 is_ipv6

    my $niok = is_ipv6 ('dead:beef:cafe:babe::f0ad');

=head3 Parameters

Identical to L</ipv6_parse>.

=head3 Returns

This returns the return value of L</ipv6_parse>, called in scalar
context, if it does parse out correctly, otherwise it returns
C<undef>. Unlike L</ipv6_parse>, is_ipv6 does not throw exceptions.

=head2 ipv6_chkip

    my $niok = ipv6_chkip ('dead:beef:cafe:babe::f0ad');

=head3 Parameters

An IPv6 address string, without a prefix.

=head3 Returns

Something true if it's a valid address; something false otherwise.


=head2 to_string_preferred

    
    use Net::IPv6Addr;
    print Net::IPv6Addr::to_string_preferred ('dead:beef:cafe:babe::f0ad');


produces output

    dead:beef:cafe:babe:0:0:0:f0ad

(This example is included as L<F<preferred.pl>|https://api.metacpan.org/source/BKB/Net-IPv6Addr-0.91/examples/preferred.pl> in the distribution.)


=head3 Parameters

If used as an object method, none; if used as a subroutine,
an IPv6 address string in any format.

=head3 Returns

The IPv6 address, formatted in the "preferred" way (as detailed by
RFC1884).

=head3 Notes

Invalid input will generate an exception.

=head2 to_string_compressed

=head3 Parameters

If used as an object method, none; if used as a subroutine,
an IPv6 address string in any format.

=head3 Returns

The IPv6 address in the "compressed" format detailed by L<RFC1884|/RFCs>.

=head3 Notes

Invalid input will generate an exception.


=head2 to_string_ipv4

=head3 Parameters

If used as an object method, none; if used as a subroutine,
an IPv6 address string in any format.

=head3 Returns

The IPv6 address in the IPv4 format detailed by L<RFC1884|/RFCs>.

=head3 Notes

Invalid input (such as an address that was not originally IPv4)
will generate an exception.


=head2 to_string_ipv4_compressed

=head3 Parameters

If used as an object method, none; if used as a subroutine,
an IPv6 address string in any format.

=head3 Returns

The IPv6 address in the compressed IPv4 format detailed by
L<RFC1884|/RFCs>.

=head3 Notes

Invalid input (such as an address that was not originally IPv4)
will generate an exception.


=head2 to_string_base85

=head3 Parameters

If used as an object method, none; if used as a subroutine,
an IPv6 address string in any format.

=head3 Returns

The IPv6 address in the style detailed by L<RFC1924|/RFCs>.

=head3 Notes

Invalid input will generate an exception. 

The base 85 encoding described in RFC1924 was an April Fool's joke.

=head2 to_bigint

=head3 Parameters

If used as an object method, none; if used as a subroutine,
an IPv6 address string in any format.

=head3 Returns

The BigInt representation of the given IPv6 address.

=head3 Notes

Invalid input will generate an exception.

=head2 to_array

=head3 Parameters

If used as an object method, none; if used as a subroutine,
an IPv6 address string in any format.

=head3 Returns

An array [0..7] of 16-bit hexadecimal numbers (strings).

=head3 Notes

Invalid input will generate an exception.

=head2 to_intarray

=head3 Parameters

If used as an object method, none; if used as a subroutine,
an IPv6 address string in any format.

=head3 Returns

An array [0..7] of numbers.

=head3 Notes

Invalid input will generate an exception.

=head2 to_string_ip6_int

=head3 Parameters

If used as an object method, none; if used as a subroutine,
an IPv6 address string in any format.

=head3 Returns

The reverse-address pointer as defined by L<RFC1886|/RFCs>.

=head3 Notes

Invalid input will generate an exception.

=head2 in_network_of_size

    my $obj = $x->in_network_of_size ($n);

Given an input IPv6 address $x, this returns the C<$n>
most-significant bits of C<$x> as a new Net::IPv6Addr object.

=head3 Parameters

If used as an object method, network size in bits

    my $obj = $x->in_network_of_size (64);

If used as a subroutine, an IPv6 address string in any format
and network size in bits.

    my $obj = Net::IPv6::in_network_of_size ($addr, 64);

Network size may be given with / notation:

    my $obj = Net::IPv6::in_network_of_size ("$addr/64");

=head3 Returns

Network IPv6Addr of given size.

=head3 Notes

Invalid input will generate an exception. 

Prior to version 0.9, this did not work correctly unless the net size
was a multiple of sixteen.

=head2 in_network

    my $ok = $x->in_network ("aa:bb:cc:dd::/64");

=head3 Parameters

If used as an object method, a network and its size in bits

    my $ok = $x->in_network ("aa:bb:cc:dd::", 64);

If used as a subroutine, an IPv6 address string in any format,
followed by a network address string and its size in bits.

    my $addr = 'fd00::54:20c:29fe:fe14:ab4b';
    my $ok = Net::IPv6Addr::in_network ($addr, "aa:bb:cc:dd::", 64);

The network size may also be given with the / notation after the
network address string:

    my $ok = $x->in_network("aa:bb:cc:dd::/64");

=head3 Returns

A true value if the address is a member of the network, false otherwise.

=head3 Notes

Invalid input will generate an exception.

Prior to version 0.9, this did not work correctly unless the net size
was a multiple of sixteen.

=head1 EXPORTS

As of version 0.91, L</in_network>, L</in_network_of_size>, L</ipv6_chkip>, L</ipv6_parse>, L</is_ipv6> may
be exported on demand. The other routines need to be called in
fully-qualified format, like C<Net::IPv6Addr::is_ipv6>. The exported
functions may all be exported using

    use Net::IPv6Addr ':all';

=head1 BUGS

Known deficiencies include the following.

=over

=item No tests

Many of the routines do not have any tests. This means that
alterations to the code may have unintentionally altered the module's
behaviour.

=item Compressed + IPv4 are not accepted

As of 0.91, the valid format consisting of a
compressed-but-non-zero six-element IPv6 followed by an IPv4 is not
accepted by the module. TODO tests are in F<t/Regexp-IPv6.t>.

=back

Report further bugs at
L<https://rt.cpan.org/Dist/Display.html?Name=Net-IPv6Addr> or by email
to C<bug-Net-IPv6Addr [at] rt.cpan.org>.

=head1 DEPENDENCIES

L<Net::IPv4Addr>, L<Math::Base85>, L<Math::BigInt>

=head2 Reverse dependencies

L<Search grep.cpan.me for uses of this module|http://grep.cpan.me/?q=Net%3A%3AIPv6Addr%5Cb>

=head1 SEE ALSO

=head2 RFCs

The following RFCs (requests for comment, internet standards
documentation) contain information on IPv6.

L<RFC1884|https://www.ietf.org/rfc/rfc1884.txt>,
L<RFC1886|https://www.ietf.org/rfc/rfc1886.txt>,
L<RFC1924|https://www.ietf.org/rfc/rfc1924.txt> (April Fool's joke),
L<RFC2373|https://www.ietf.org/rfc/rfc2373.txt>

The links go to the plain text online versions of the RFCs.

=head2 Other CPAN modules

There are a very large number of CPAN modules which deal with IPv6
addresses. The following list gives all the ones I know about which
overlap with this module, in alphabetical order.

=over

=item L<Data::Checker::IP>

Uses L</NetAddr::IP>.

=item L<Data::Validate::IP>

Uses L<Socket> to validate IP addresses.

=item L<IPv6::Address>

=item L<Net::IP>

=item L<Net::IP::Minimal>

=item L<Net::IPAddress::Util>

=item L<Net::IPv6Address>

=item L<NetAddr::IP>

=item L<NetAddr::IP::Lite>

=item L<Regexp::IPv6>

Tests and one regex from C<Regexp::IPv6> are included in this
module. Unlike C<Net::IPv6Addr>, this module disallows the valid C<::>
IP address, which means "the unspecified addresses". See the module's
documentation for details.

=back

=head2 Other

=over

=item Online validator

L<https://www.helpsystems.com/intermapper/ipv6-test-address-validation>

=back

=head1 HISTORY

This module was originally written by Tony Monroe in 2001 to simplify
the task of maintaining DNS records after he set himself up with
Freenet6.

In 2017 the module was adopted by Ben Bullock with the help of Neil
Bowers as part of "CPAN day".

Exporting of some functions was added in version 0.8.

For version 0.91, IPv6 validating tests and an IPv4 validating regexp
were taken from L<Regexp::IPv6> by Salvador Fandiño García.

=head1 AUTHOR

Tony Monroe(*)

The module's interface resembles L<Net::IPv4Addr> by Francis
J. Lacoste E<lt>francis dot lacoste at iNsu dot COME<gt>.

Some fixes and subroutines from Jyrki Soini E<lt>jyrki dot soini
at sonera dot comE<gt>.

(*) The current module maintainer (BKB) does not have any contact
information for Tony Monroe. Those wishing to contact him can do so
via Neil Bowers (see his CPAN user page for contact details).

=head1 LICENSE

This distribution is copyright (c) 2001-2002 Tony Monroe.  All rights
reserved.  This software is distributed under the same license terms
as Perl itself.  This software comes with NO WARRANTIES WHATSOEVER,
express, implied, or otherwise.

