NAME¶
Net::DNS::RR - DNS resource record base class
SYNOPSIS¶
use Net::DNS;
$rr = new Net::DNS::RR('example.com IN A 192.0.2.99');
$rr = new Net::DNS::RR(
name => 'example.com',
type => 'A',
address => '192.0.2.99'
);
DESCRIPTION¶
Net::DNS::RR is the base class for DNS Resource Record (RR) objects. See also
the manual pages for each specific RR type.
METHODS¶
WARNING!!! Do not assume the RR objects you receive from a query are of a
particular type -- you must always check the object type before calling any of
its methods. If you call an unknown method, you will get an error message and
execution will be terminated.
new (from string)¶
$a = new Net::DNS::RR('host.example.com. 86400 A 192.0.2.1');
$mx = new Net::DNS::RR('example.com. 7200 MX 10 mailhost.example.com.');
$cname = new Net::DNS::RR('www.example.com 300 IN CNAME host.example.com');
$txt = new Net::DNS::RR('txt.example.com 3600 HS TXT "text data"');
Returns an RR object of the appropriate type, or a "Net::DNS::RR"
object if the type is not implemented. The attribute values are extracted from
the string passed by the user. The syntax of the argument string follows the
RFC1035 specification for zone files, and is compatible with the result
returned by the string method.
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 "Net::DNS::Update" manual
page for additional examples.
All names are interpreted as fully qualified domain names. The trailing dot (.)
is optional.
new (from hash)¶
$rr = new Net::DNS::RR(
name => 'host.example.com',
ttl => 86400,
class => 'IN',
type => 'A',
address => '192.0.2.1'
);
$rr = new Net::DNS::RR(
name => 'txt.example.com',
type => 'TXT',
txtdata => [ 'one', 'two' ]
);
Returns an RR object of the appropriate type, or a "Net::DNS::RR"
object if the type is not implemented. See the manual pages for each RR type
to see what fields the type requires.
The "name" and "type" fields are required; all others are
optional. If omitted, "ttl" defaults to 0 and "class"
defaults to IN. Omitting the optional fields is useful for creating the empty
RDATA sections required for certain dynamic update operations.
decode¶
( $rr, $next ) = decode Net::DNS::RR( \$data, $offset, @opaque );
Decodes a DNS resource record at the specified location within a DNS packet.
The argument list consists of a reference to the buffer containing the packet
data and offset indicating where resource record begins. Remaining arguments,
if any, are passed as opaque data to subordinate decoders.
Returns a "Net::DNS::RR" object and the offset of the next record in
the packet.
An exception is raised if the data buffer contains insufficient or corrupt data.
Any remaining arguments are passed as opaque data to subordinate decoders and do
not form part of the published interface.
encode¶
$data = $rr->encode( $offset, @opaque );
Returns the "Net::DNS::RR" in binary format suitable for inclusion in
a DNS packet buffer.
The offset indicates the intended location within the packet data where the
"Net::DNS::RR" is to be stored.
Any remaining arguments are opaque data which are passed intact to subordinate
encoders.
canonical¶
$data = $rr->canonical;
Returns the "Net::DNS::RR" in canonical binary format suitable for
DNSSEC signature validation.
The absence of the associative array argument signals to subordinate encoders
that the canonical uncompressed lower case form of embedded domain names is to
be used.
print¶
$rr->print;
Prints the record to the standard output. Calls the
string method to get
the RR string representation.
string¶
print $rr->string, "\n";
Returns a string representation of the RR using the zone file format described
in RFC1035. All domain names are fully qualified with trailing dot. This
differs from RR attribute methods, which omit the trailing dot.
owner name¶
$owner = $rr->name;
Returns the owner name of the record.
type¶
$type = $rr->type;
Returns the record type.
class¶
$class = $rr->class;
Resource record class.
ttl¶
$ttl = $rr->ttl;
$ttl = $rr->ttl(3600);
Resource record time to live in seconds.
rdata¶
$rr = new Net::DNS::RR( type => NULL, rdata => 'arbitrary' );
Resource record data section when viewed as opaque octets.
rdstring¶
$rdstring = $rr->rdstring;
Returns a string representation of the RR-specific data.
plain¶
$plain = $rr->plain;
Returns a simplified single line representation of the RR using the zone file
format defined in RFC1035. This facilitates interaction with programs like
nsupdate which have simplified RR parsers.
token¶
@token = $rr->token;
Returns a token list representation of the RR zone file string.
Sorting of RR arrays¶
Sorting of RR arrays is done by
Net::DNS::rrsort(), see documentation for
Net::DNS. This package provides class methods to set the comparator function
used for a particular RR based on its attributes.
set_rrsort_func¶
Net::DNS::RR::MX->set_rrsort_func(
'preference',
sub { $Net::DNS::a->preference <=> $Net::DNS::b->preference }
);
Net::DNS::RR::MX->set_rrsort_func(
'default_sort',
Net::DNS::RR::MX->get_rrsort_func('preference')
);
set_rrsort_func() must be called as a class method. The first argument is
the attribute name on which the sorting is to take place. If you specify
"default_sort" then that is the sort algorithm that will be used
when
rrsort() is called without an RR attribute as argument.
The second argument is a reference to a comparison function that uses the global
variables $a and $b in the Net::DNS package. During sorting, the variables $a
and $b will contain references to objects of the class whose
set_rrsort_func() was called. The above sorting function will only be
applied to Net::DNS::RR::MX objects.
The above example is the sorting function implemented in MX.
COPYRIGHT¶
Copyright (c)1997-2002 Michael Fuhr.
Portions Copyright (c)2002-2004 Chris Reinhardt.
Portions Copyright (c)2005-2007 Olaf Kolkman.
Portions Copyright (c)2007,2012 Dick Franks.
All rights reserved.
This program is free software; you may redistribute it and/or modify it under
the same terms as Perl itself.
SEE ALSO¶
perl, Net::DNS, Net::DNS::Question, Net::DNS::Packet, Net::DNS::Update, RFC1035
Section 4.1.3, RFC1123, RFC3597