package Net::DNS::RR;
use strict;
use vars qw($VERSION $AUTOLOAD);
use Carp;
use Net::DNS;
use Net::DNS::RR::Unknown;
$VERSION = (qw$Revision: 1.1 $)[1];
=head1 NAME
Net::DNS::RR - DNS Resource Record class
=head1 SYNOPSIS
C<use Net::DNS::RR>
=head1 DESCRIPTION
C<Net::DNS::RR> is the base class for DNS Resource Record (RR) objects.
See also the manual pages for each RR type.
=head1 METHODS
B<WARNING!!!> Don't assume the RR objects you receive from a query
are of a particular type -- always check an object's type before calling
any of its methods. If you call an unknown method, you'll get a nasty
warning message and C<Net::DNS::RR> will return C<undef> to the caller.
=cut
use vars qw(%RR %_LOADED $RR_REGEX);
BEGIN {
%RR = map { $_ => 1 } qw(
A
AAAA
AFSDB
CNAME
CERT
DNAME
EID
HINFO
ISDN
LOC
MB
MG
MINFO
MR
MX
NAPTR
NIMLOC
NS
NSAP
NULL
PTR
PX
RP
RT
SOA
SRV
TKEY
TSIG
TXT
X25
OPT
);
eval { require Net::DNS::RR::SIG; };
unless ($@) {
$RR{'SIG'} = 1;
eval { require Net::DNS::RR::NXT; };
unless ($@) {
$RR{'NXT'} = 1;
} else {
die $@;
}
eval { require Net::DNS::RR::KEY; };
unless ($@) {
$RR{'KEY'} = 1;
} else {
die $@;
}
eval { require Net::DNS::RR::DS; };
unless ($@) {
$RR{'DS'} = 1;
} else {
die $@;
}
eval { require Net::DNS::RR::RRSIG; };
unless ($@) {
$RR{'RRSIG'} = 1;
eval { require Net::DNS::RR::NSEC; };
unless ($@) {
$RR{'NSEC'} = 1;
} else {
die $@;
}
eval { require Net::DNS::RR::DNSKEY; };
unless ($@) {
$RR{'DNSKEY'} = 1;
} else {
die $@;
}
}
}
}
sub build_regex {
my $classes = join('|', keys %Net::DNS::classesbyname, 'CLASS\\d+');
my $types = join('|', sort { length $b <=> length $a } keys %Net::DNS::typesbyname);
$types .= '|TYPE\\d+';
$RR_REGEX = " ^
\\s*
(\\S+) # name anything non-space will do
\\s*
(\\d+)?
\\s*
($classes)?
\\s*
($types)?
\\s*
(.*)
\$";
}
=head2 new (from string)
$a = Net::DNS::RR->new("foo.example.com. 86400 A 10.1.2.3");
$mx = Net::DNS::RR->new("example.com. 7200 MX 10 mailhost.example.com.");
$cname = Net::DNS::RR->new("www.example.com 300 IN CNAME www1.example.com");
$txt = Net::DNS::RR->new("baz.example.com 3600 HS TXT 'text record'");
Returns a C<Net::DNS::RR> object of the appropriate type and
initialized from the string passed by the user. The format of the
string is that used in zone files, and is compatible with the string
returned by C<< Net::DNS::RR->string >>.
The name and RR type are required; all other information is optional.
If omitted, the TTL defaults to 0 and the RR class defaults to IN.
Omitting the optional fields is useful for creating the empty RDATA
sections required for certain dynamic update operations. See the
C<Net::DNS::Update> manual page for additional examples.
All names must be fully qualified. The trailing dot (.) is optional.
=head2 new (from hash)
$rr = Net::DNS::RR->new(
name => "foo.example.com",
ttl => 86400,
class => "IN",
type => "A",
address => "10.1.2.3",
);
$rr = Net::DNS::RR->new(
name => "foo.example.com",
type => "A",
);
Returns an RR object of the appropriate type, or a C<Net::DNS::RR>
object if the type isn't implemented. See the manual pages for
each RR type to see what fields the type requires.
The C<Name> and C<Type> fields are required; all others are optional.
If omitted, C<TTL> defaults to 0 and C<Class> defaults to IN. Omitting
the optional fields is useful for creating the empty RDATA sections
required for certain dynamic update operations.
The fields are case-insensitive, but starting each with uppercase
is recommended.
=cut
sub new {
if (@_ == 8 && ref $_[6]) {
return new_from_data(@_);
}
if (@_ == 2 || @_ == 3) {
return new_from_string(@_);
}
return new_from_hash(@_);
}
sub new_from_data {
my $class = shift;
my ($name, $rrtype, $rrclass, $ttl, $rdlength, $data, $offset) = @_;
my $self = {
'name' => $name,
'type' => $rrtype,
'class' => $rrclass,
'ttl' => $ttl,
'rdlength' => $rdlength,
'rdata' => substr($$data, $offset, $rdlength),
};
if ($RR{$rrtype}) {
my $subclass = $class->_get_subclass($rrtype);
return $subclass->new($self, $data, $offset);
} else {
return Net::DNS::RR::Unknown->new($self, $data, $offset);
}
}
sub new_from_string {
my ($class, $rrstring, $update_type) = @_;
build_regex() unless $RR_REGEX;
$rrstring =~ s/;.*//g;
($rrstring =~ m/$RR_REGEX/xso) ||
confess qq|qInternal Error: "$rrstring" did not match RR pat.\nPlease report this to the author!\n|;
my $name = $1;
my $ttl = $2 || 0;
my $rrclass = $3 || '';
my $rrtype = $4 || '';
my $rdata = $5 || '';
$rdata =~ s/\s+$// if $rdata;
$name =~ s/\.$// if $name;
$rrtype = Net::DNS::typesbyval(Net::DNS::typesbyname($rrtype)) if $rrtype =~ m/^TYPE\d+/;
$rrclass = Net::DNS::classesbyval(Net::DNS::classesbyname($rrclass)) if $rrclass =~ m/^CLASS\d+/;
if (!$rrtype && $rrclass && $rrclass eq 'ANY') {
$rrtype = 'ANY';
$rrclass = 'IN';
} elsif (!$rrclass) {
$rrclass = 'IN';
}
$rrtype ||= 'ANY';
if ($update_type) {
$update_type = lc $update_type;
if ($update_type eq 'yxrrset') {
$ttl = 0;
$rrclass = 'ANY' unless $rdata;
} elsif ($update_type eq 'nxrrset') {
$ttl = 0;
$rrclass = 'NONE';
$rdata = '';
} elsif ($update_type eq 'yxdomain') {
$ttl = 0;
$rrclass = 'ANY';
$rrtype = 'ANY';
$rdata = '';
} elsif ($update_type eq 'nxdomain') {
$ttl = 0;
$rrclass = 'NONE';
$rrtype = 'ANY';
$rdata = '';
} elsif ($update_type =~ /^(rr_)?add$/) {
$ttl = 86400 unless $ttl;
} elsif ($update_type =~ /^(rr_)?del(ete)?$/) {
$ttl = 0;
$rrclass = $rdata ? 'NONE' : 'ANY';
}
}
my $self = {
'name' => $name,
'type' => $rrtype,
'class' => $rrclass,
'ttl' => $ttl,
'rdlength' => 0,
'rdata' => '',
};
if ($RR{$rrtype} && $rdata !~ m/^\s*\\ my $subclass = $class->_get_subclass($rrtype);
return $subclass->new_from_string($self, $rdata);
} elsif ($RR{$rrtype}) { $rdata =~ m/\\\
my $rdlength = $1;
my $hexdump = $2;
$hexdump =~ s/\s*//g;
die "$rdata is inconsistent; length does not match content"
if length($hexdump) != $rdlength*2;
$rdata = pack('H*', $hexdump);
return Net::DNS::RR->new_from_data(
$name,
$rrtype,
$rrclass,
$ttl,
$rdlength,
\$rdata,
length($rdata) - $rdlength
);
} elsif ($rdata=~/\s*\\\ die 'Expected RFC3597 representation of RDATA'
unless $rdata =~ m/\\\
my $rdlength = $1;
my $hexdump = $2;
$hexdump =~ s/\s*//g;
die "$rdata is inconsistent; length does not match content"
if length($hexdump) != $rdlength*2;
$rdata = pack('H*', $hexdump);
return Net::DNS::RR->new_from_data(
$name,
$rrtype,
$rrclass,
$ttl,
$rdlength,
\$rdata,
length($rdata) - $rdlength
);
} else {
bless $self, $class;
return $self
}
}
sub new_from_hash {
my $class = shift;
my %tempself = @_;
my $self = {};
my ($key, $val);
while (($key, $val) = each %tempself) {
$self->{lc($key)} = $val;
}
Carp::croak('RR name not specified')
unless exists $self->{'name'};
Carp::croak('RR type not specified')
unless exists $self->{'type'};
$self->{'ttl'} ||= 0;
$self->{'class'} ||= 'IN';
$self->{'rdlength'} = length $self->{'rdata'}
if $self->{'rdata'};
if ($RR{$self->{'type'}}) {
my $subclass = $class->_get_subclass($self->{'type'});
if (uc $self->{'type'} ne 'OPT') {
bless $self, $subclass;
return $self;
} else {
return $subclass->new_from_hash($self);
}
} elsif ($self->{'type'} =~ /TYPE\d+/) {
bless $self, 'Net::DNS::RR::Unknown';
return $self;
} else {
bless $self, $class;
return $self;
}
}
sub DESTROY {}
=head2 print
$rr->print;
Prints the record to the standard output. Calls the
B<string> method to get the RR's string representation.
=cut
sub print {
my $self = shift;
print $self->string, "\n";
}
=head2 string
print $rr->string, "\n";
Returns a string representation of the RR. Calls the
B<rdatastr> method to get the RR-specific data.
=cut
sub string {
my $self = shift;
return join("\t",
"$self->{'name'}.",
$self->{'ttl'},
$self->{'class'},
$self->{'type'},
(defined $self->rdatastr and length $self->rdatastr) ? $self->rdatastr : '; no data',
);
}
=head2 rdatastr
$s = $rr->rdatastr;
Returns a string containing RR-specific data. Subclasses will need
to implement this method.
=cut
sub rdatastr {
my $self = shift;
return exists $self->{'rdlength'}
? "; rdlength = $self->{'rdlength'}"
: '';
}
=head2 name
$name = $rr->name;
Returns the record's domain name.
=head2 type
$type = $rr->type;
Returns the record's type.
=head2 class
$class = $rr->class;
Returns the record's class.
=cut
sub class {
my $self = shift;
if (@_) {
$self->{'class'} = shift;
} elsif (!exists $self->{'class'}) {
Carp::carp('class: no such method');
return undef;
}
return $self->{'class'};
}
=head2 ttl
$ttl = $rr->ttl;
Returns the record's time-to-live (TTL).
=head2 rdlength
$rdlength = $rr->rdlength;
Returns the length of the record's data section.
=head2 rdata
$rdata = $rr->rdata
Returns the record's data section as binary data.
=cut
sub rdata {
my $self = shift;
my $retval = undef;
if (@_ == 2) {
my ($packet, $offset) = @_;
$retval = $self->rr_rdata($packet, $offset);
}
elsif (exists $self->{'rdata'}) {
$retval = $self->{'rdata'};
}
return $retval;
}
sub rr_rdata {
my $self = shift;
return exists $self->{'rdata'} ? $self->{'rdata'} : '';
}
sub data {
my ($self, $packet, $offset) = @_;
my $data;
if (uc($self->{'type'}) eq 'TSIG' || uc($self->{'type'}) eq 'TKEY') {
my $tmp_packet = Net::DNS::Packet->new('');
$data = $tmp_packet->dn_comp($self->{'name'}, 0);
} elsif (uc($self->{'type'}) eq 'OPT') {
my $tmp_packet = Net::DNS::Packet->new('');
$data = $tmp_packet->dn_comp('', 0);
} else {
$data = $packet->dn_comp($self->{'name'}, $offset);
}
my $qtype = uc($self->{'type'});
my $qtype_val = ($qtype =~ m/^\d+$/) ? $qtype : Net::DNS::typesbyname($qtype);
$qtype_val = 0 if !defined($qtype_val);
my $qclass = uc($self->{'class'});
my $qclass_val = ($qclass =~ m/^\d+$/) ? $qclass : Net::DNS::classesbyname($qclass);
$qclass_val = 0 if !defined($qclass_val);
$data .= pack('n', $qtype_val);
if (uc($self->{'type'}) ne 'OPT') {
$data .= pack('n', $qclass_val);
} else {
$data .= pack('n', $self->{'class'});
}
$data .= pack('N', $self->{'ttl'});
$offset += length($data) + &Net::DNS::INT16SZ;
my $rdata = $self->rdata($packet, $offset);
$data .= pack('n', length $rdata);
$data .= $rdata;
return $data;
}
sub _canonicaldata {
my $self = shift;
my $data='';
{
my @dname= split /\./,lc($self->{'name'});
for (my $i=0;$i<@dname;$i++){
$data .= pack ('C',length $dname[$i] );
$data .= $dname[$i] ;
}
$data .= pack ('C','0');
}
$data .= pack('n', Net::DNS::typesbyname(uc($self->{'type'})));
$data .= pack('n', Net::DNS::classesbyname(uc($self->{'class'})));
$data .= pack('N', $self->{'ttl'});
my $rdata = $self->_canonicalRdata;
$data .= pack('n', length $rdata);
$data .= $rdata;
return $data;
}
sub _canonicalRdata {
my $self = shift;
my $rdata = $self->rr_rdata;
return $rdata;
}
sub _name2wire {
my ($self,$name)=@_;
my $rdata = '';
my @dname = split(m/\./, lc $name);
for (@dname) {
$rdata .= pack('C', length $_);
$rdata .= $_ ;
}
$rdata .= pack('C', '0');
return $rdata;
}
sub AUTOLOAD {
my ($self) = @_;
my ($name) = $AUTOLOAD =~ m/^.*::(.*)$/;
unless (exists $self->{$name}) {
my $rr_string = $self->string;
Carp::carp(<<"AMEN");
***
*** WARNING!!! The program has attempted to call the method
*** "$name" for the following RR object:
***
*** $rr_string
***
*** This object doesn't have a method "$name". THIS IS A BUG
*** IN THE CALLING SOFTWARE, which has incorrectly assumed that
*** the object would be of a particular type. The calling
*** software should check the type of each RR object before
*** calling any of its methods.
***
*** Net::DNS has returned undef to the caller.
***
AMEN
return;
}
no strict q/refs/;
# Build a method in the class.
*{$AUTOLOAD} = sub {
my ($self, $new_val) = @_;
if (defined $new_val) {
$self->{$name} = $new_val;
}
return $self->{$name};
};
# And jump over to it.
goto &{$AUTOLOAD};
}
#
# Net::DNS::RR->_get_subclass($type)
#
# Return a subclass, after loading a subclass (if needed)
#
sub _get_subclass {
my ($class, $type) = @_;
return unless $type and $RR{$type};
my $subclass = join('::', $class, $type);
unless ($_LOADED{$subclass}) {
eval "require $subclass";
die $@ if $@;
$_LOADED{$subclass}++;
}
return $subclass;
}
sub STORABLE_freeze {
my ($self, $cloning) = @_;
return if $cloning;
return ('', {%$self});
}
sub STORABLE_thaw {
my ($self, $cloning, undef, $data) = @_;
%{$self} = %{$data};
__PACKAGE__->_get_subclass($self->{'type'});
return $self;
}
=head1 BUGS
This version of C<Net::DNS::RR> does little sanity checking on user-created
RR objects.
=head1 COPYRIGHT
Copyright (c) 1997-2002 Michael Fuhr.
Portions Copyright (c) 2002-2003 Chris Reinhardt.
All rights reserved. This program is free software; you may redistribute
it and/or modify it under the same terms as Perl itself.
EDNS0 extensions by Olaf Kolkman.
=head1 SEE ALSO
L<perl(1)>, L<Net::DNS>, L<Net::DNS::Resolver>, L<Net::DNS::Packet>,
L<Net::DNS::Update>, L<Net::DNS::Header>, L<Net::DNS::Question>,
RFC 1035 Section 4.1.3
=cut
1;