Net::DNS::RR(3) User Contributed Perl Documentation Net::DNS::RR(3)
NAME
Net::DNS::RR - DNS resource record base class
SYNOPSIS
use Net::DNS;
$rr = Net::DNS::RR->new('example.com IN AAAA 2001:DB8::1');
$rr = Net::DNS::RR->new(
owner => 'example.com',
type => 'AAAA',
address => '2001:DB8::1'
);
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)
$aaaa = Net::DNS::RR->new('host.example.com. 86400 AAAA 2001:DB8::1');
$mx = Net::DNS::RR->new('example.com. 7200 MX 10 mailhost.example.com.');
$cname = Net::DNS::RR->new('www.example.com 300 IN CNAME host.example.com');
$txt = Net::DNS::RR->new('txt.example.com 3600 HS TXT "text data"');
Returns an object of the appropriate RR 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 owner and RR type are required; all other information is optional.
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 = Net::DNS::RR->new(%hash);
$rr = Net::DNS::RR->new(
owner => 'host.example.com',
ttl => 86400,
class => 'IN',
type => 'AAAA',
address => '2001:DB8::1'
);
$rr = Net::DNS::RR->new(
owner => 'txt.example.com',
type => 'TXT',
txtdata => [ 'one', 'two' ]
);
Returns an object of the appropriate RR type, or a Net::DNS::RR object
if the type is not implemented. Consult the relevant manual pages for
the usage of type specific attributes.
The owner and RR type are required; all other information is optional.
Omitting optional attributes 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 resource record to the currently selected output filehandle.
Calls the string method to get the formatted RR representation.
string
print $rr->string, "\n";
Returns a string representation of the RR using the master file format
mandated by RFC1035. All domain names are fully qualified with
trailing dot. This differs from RR attribute methods, which omit the
trailing dot.
plain
$plain = $rr->plain;
Returns a simplified single-line representation of the RR. This
facilitates interaction with programs like nsupdate which have
rudimentary parsers.
token
@token = $rr->token;
Returns a token list representation of the RR zone file string.
generic
$generic = $rr->generic;
Returns the generic RR representation defined in RFC3597. This
facilitates creation of zone files containing RRs unrecognised by
outdated nameservers and provisioning software.
owner name
$name = $rr->owner;
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 = Net::DNS::RR->new( 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.
rdlength
$rdlength = $rr->rdlength;
Returns the uncompressed length of the encoded RR-specific data.
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
my $function = sub { ## numerically ascending order
$Net::DNS::a->{'preference'} <=> $Net::DNS::b->{'preference'};
};
Net::DNS::RR::MX->set_rrsort_func( 'preference', $function );
Net::DNS::RR::MX->set_rrsort_func( 'default_sort', $function );
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 get_rrsort_func() is called without an RR attribute as
argument.
The second argument is a reference to a comparator 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.
get_rrsort_func
$function = Net::DNS::RR::MX->get_rrsort_func('preference');
$function = Net::DNS::RR::MX->get_rrsort_func();
get_rrsort_func() returns a reference to the comparator function.
COPYRIGHT
Copyright (c)1997-2001 Michael Fuhr.
Portions Copyright (c)2002,2003 Chris Reinhardt.
Portions Copyright (c)2005-2007 Olaf Kolkman.
Portions Copyright (c)2007,2012 Dick Franks.
All rights reserved.
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.
SEE ALSO
perl(1), Net::DNS(3), Net::DNS::Question(3), Net::DNS::Packet(3),
Net::DNS::Update(3), RFC1035 Section 4.1.3, RFC1123, RFC3597
perl v5.30.3 2020-10-23 Net::DNS::RR(3)
net-dns 1.280.0 - Generated Sun Oct 25 13:10:25 CDT 2020