package Net::DNS::RR::APL;

use strict;
use warnings;
our $VERSION = (qw$Id: APL.pm 1814 2020-10-14 21:49:16Z willem $)[2];

use base qw(Net::DNS::RR);


=head1 NAME

Net::DNS::RR::APL - DNS APL resource record

=cut

use integer;

use Carp;


sub _decode_rdata {			## decode rdata from wire-format octet string
	my $self = shift;
	my ( $data, $offset ) = @_;

	my $limit = $offset + $self->{rdlength};

	my $aplist = $self->{aplist} = [];
	while ( $offset < $limit ) {
		my $xlen = unpack "\@$offset x3 C", $$data;
		my $size = ( $xlen & 0x7F );
		my $item = bless {}, 'Net::DNS::RR::APL::Item';
		$item->{negate} = $xlen - $size;
		@{$item}{qw(family prefix address)} = unpack "\@$offset n C x a$size", $$data;
		$offset += $size + 4;
		push @$aplist, $item;
	}
	croak('corrupt APL data') unless $offset == $limit;	# more or less FUBAR
	return;
}


sub _encode_rdata {			## encode rdata as wire-format octet string
	my $self = shift;

	my @rdata;
	my $aplist = $self->{aplist};
	foreach (@$aplist) {
		my $address = $_->{address};
		$address =~ s/[\000]+$//;			# strip trailing null octets
		my $xlength = ( $_->{negate} ? 0x80 : 0 ) | length($address);
		push @rdata, pack 'n C2 a*', @{$_}{qw(family prefix)}, $xlength, $address;
	}
	return join '', @rdata;
}


sub _format_rdata {			## format rdata portion of RR string.
	my $self = shift;

	my $aplist = $self->{aplist};
	my @rdata  = map { $_->string } @$aplist;
	return @rdata;
}


sub _parse_rdata {			## populate RR from rdata in argument list
	my $self = shift;

	$self->aplist(@_);
	return;
}


sub aplist {
	my $self = shift;

	while ( scalar @_ ) {					# parse apitem strings
		last unless $_[0] =~ m#[!:./]#;
		shift =~ m#^(!?)(\d+):(.+)/(\d+)$#;
		my $n = $1 ? 1 : 0;
		my $f = $2 || 0;
		my $a = $3;
		my $p = $4 || 0;
		$self->aplist( negate => $n, family => $f, address => $a, prefix => $p );
	}

	my $aplist = $self->{aplist} ||= [];
	if ( my %argval = @_ ) {				# parse attribute=value list
		my $item = bless {}, 'Net::DNS::RR::APL::Item';
		while ( my ( $attribute, $value ) = each %argval ) {
			$item->$attribute($value) unless $attribute eq 'address';
		}
		$item->address( $argval{address} );		# address must be last
		push @$aplist, $item;
	}

	my @ap = @$aplist;
	return unless defined wantarray;
	return wantarray ? @ap : join ' ', map { $_->string } @ap;
}


########################################


package Net::DNS::RR::APL::Item;	## no critic ProhibitMultiplePackages

use Net::DNS::RR::A;
use Net::DNS::RR::AAAA;

my %family = qw(1 Net::DNS::RR::A	2 Net::DNS::RR::AAAA);


sub negate {
	my $self = shift;
	return $self->{negate} = shift if scalar @_;
	return $self->{negate};
}


sub family {
	my $self = shift;

	$self->{family} = 0 + shift if scalar @_;
	return $self->{family} || 0;
}


sub prefix {
	my $self = shift;

	$self->{prefix} = 0 + shift if scalar @_;
	return $self->{prefix} || 0;
}


sub address {
	my $self = shift;

	my $family = $family{$self->family} || die 'unknown address family';
	return bless( {%$self}, $family )->address unless scalar @_;

	my $bitmask = $self->prefix;
	my $address = bless( {}, $family )->address(shift);
	return $self->{address} = pack "B$bitmask", unpack 'B*', $address;
}


sub string {
	my $self = shift;

	my $not = $self->{negate} ? '!' : '';
	my ( $family, $address, $prefix ) = ( $self->family, $self->address, $self->prefix );
	return "$not$family:$address/$prefix";
}


1;
__END__


=head1 SYNOPSIS

    use Net::DNS;
    $rr = Net::DNS::RR->new('name IN APL aplist');

=head1 DESCRIPTION

DNS Address Prefix List (APL) record

=head1 METHODS

The available methods are those inherited from the base class augmented
by the type-specific methods defined in this package.

Use of undocumented package features or direct access to internal data
structures is discouraged and could result in program termination or
other unpredictable behaviour.


=head2 aplist

    @aplist = $rr->aplist;
  
    @aplist = $rr->aplist( '1:192.168.32.0/21', '!1:192.168.38.0/28' );
  
    @aplist = $rr->aplist( '1:224.0.0.0/4', '2:FF00:0:0:0:0:0:0:0/8' );
  
    @aplist = $rr->aplist( negate  => 1,
			   family  => 1,
			   address => '192.168.38.0',
			   prefix  => 28,
			   );

Ordered, possibly empty, list of address prefix items.
Additional items, if present, are appended to the existing list
with neither prefix aggregation nor reordering.


=head2 Net::DNS::RR::APL::Item

Each element of the prefix list is a Net::DNS::RR::APL::Item
object which is inextricably bound to the APL record which
created it.

=head2 negate

    $rr->negate(1);

    if ( $rr->negate ) {
	...
    }

Boolean attribute indicating the prefix to be an address range exclusion.

=head2 family

    $family = $rr->family;
    $rr->family( $family );

Address family discriminant.

=head2 prefix

    $prefix = $rr->prefix;
    $rr->prefix( $prefix );

Number of bits comprising the address prefix.


=head2 address

    $address = $object->address;

Address portion of the prefix list item.

=head2 string

    $string = $object->string;

Returns the prefix list item in the form required in zone files.


=head1 COPYRIGHT

Copyright (c)2008 Olaf Kolkman, NLnet Labs.

Portions Copyright (c)2011,2017 Dick Franks.

All rights reserved.

Package template (c)2009,2012 O.M.Kolkman and R.W.Franks.


=head1 LICENSE

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted, provided
that the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation, and that the name of the author not be used in advertising
or publicity pertaining to distribution of the software without specific
prior written permission.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.


=head1 SEE ALSO

L<perl>, L<Net::DNS>, L<Net::DNS::RR>, RFC3123

=cut
