package Net::DNS::RR::CERT;

# Written by Mike Schiraldi <raldi@research.netsol.com> for VeriSign

use strict;
use vars qw(@ISA);

use Net::DNS;
use Net::DNS::Packet;
use MIME::Base64;

@ISA = qw(Net::DNS::RR);

my %formats = 
    (
     PKIX => 1,
     SPKI => 2,
     PGP  => 3,
     URI  => 253,
     OID  => 254,
     );

my %r_formats = reverse %formats;

my %algorithms = 
    (
     RSAMD5     => 1,
     DH         => 2,
     DSA        => 3,
     ECC        => 4,
     INDIRECT   => 252,
     PRIVATEDNS => 253,
     PRIVATEOID => 254,
     );

my %r_algorithms = reverse %algorithms;

sub new {
	my ($class, $self, $data, $offset) = @_;
        
	if ($self->{"rdlength"} > 0) {
                my ($format, $tag, $algorithm) = 
                    unpack("\@$offset n2C", $$data);

		$offset += 2 * &Net::DNS::INT16SZ + 1;
		my $certificate = substr($$data, $offset);
                
		$self->{"format"}      = $format;
		$self->{"tag"}         = $tag;
		$self->{"algorithm"}   = $algorithm;
		$self->{"certificate"} = $certificate;
	}
        
	return bless $self, $class;
}

sub new_from_string {
	my ($class, $self, $string) = @_;        
	$string or return bless $self, $class;
        
        my ($format, $tag, $algorithm, @rest) = split " ", $string;        
        @rest or return bless $self, $class;
        
        # look up mnemonics
        # the "die"s may be rash, but proceeding would be dangerous
        if ($algorithm =~ /\D/) {
                my $tmp = $algorithms{$algorithm};
                defined $tmp or die 
                    "Unknown algorithm mnemonic: '$algorithm'";
                
                $algorithm = $tmp;
        }
        
        if ($format =~ /\D/) {
                my $tmp = $formats{$format};
                defined $tmp or die 
                    "Unknown format mnemonic: '$format'";
                
                $format = $tmp;
        }
        
        $self->{"format"}      = $format;
        $self->{"tag"}         = $tag;
        $self->{"algorithm"}   = $algorithm;
        $self->{"certificate"} = MIME::Base64::decode join '', @rest;
        
	return bless $self, $class;
}

sub rdatastr {
	my $self = shift;
	my $rdatastr;
        
	if (exists $self->{"format"}) {
                my $cert = MIME::Base64::encode $self->{certificate};
                $cert =~ s/\n//g;
                
                my $format = defined $r_formats{$self->{"format"}} 
                ? $r_formats{$self->{"format"}} : $self->{"format"};
                
                my $algorithm = defined $r_algorithms{$self->{algorithm}} 
                ? $r_algorithms{$self->{algorithm}} : $self->{algorithm};
                
                $rdatastr = "$format $self->{tag} $algorithm $cert";
	}
	else {
		$rdatastr = "; no data";
	}
        
	return $rdatastr;
}

sub rr_rdata {
	my ($self, $packet, $offset) = @_;
	my $rdata = "";
        
	if (exists $self->{"format"}) {
		$rdata .= pack("n2", $self->{"format"}, $self->{tag});
		$rdata .= pack("C",  $self->{algorithm});
		$rdata .= $self->{certificate};
	}
        
	return $rdata;
}

1;
__END__

=head1 NAME

Net::DNS::RR::CERT - DNS CERT resource record

=head1 SYNOPSIS

C<use Net::DNS::RR>;

=head1 DESCRIPTION

Class for DNS Certificate (CERT) resource records. (see RFC 2538)

=head1 METHODS

=head2 format

    print "format = ", $rr->format, "\n";

Returns the format code for the certificate (in numeric form)

=head2 tag

    print "tag = ", $rr->tag, "\n";

Returns the key tag for the public key in the certificate

=head2 algorithm

    print "algorithm = ", $rr->algorithm, "\n";

Returns the algorithm used by the certificate (in numeric form)

=head2 certificate

    print "certificate = ", $rr->certificate, "\n";

Returns the data comprising the certificate itself (in raw binary form)

=head1 COPYRIGHT

Copyright (c) 1997-2000 Michael Fuhr.  All rights reserved.  This
program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. 

=head1 SEE ALSO

L<perl(1)>, L<Net::DNS>, L<Net::DNS::Resolver>, L<Net::DNS::Packet>,
L<Net::DNS::Header>, L<Net::DNS::Question>, L<Net::DNS::RR>,
RFC 2782
