Net::DNS::RR::OPT(3)

NAME
Net::DNS::RR::OPT - DNS OPT resource record

SYNOPSIS
    use Net::DNS;
    my $packet = Net::DNS::Packet->new( ... );

    $packet->header->do(1);             # extended header flag

    $packet->edns->UDPsize(1232);       # UDP payload size

    $packet->edns->option( 'NSID'           => '7261776279746573' );
    $packet->edns->option( 'TCP-KEEPALIVE'  => 200 );
    $packet->edns->option( 'DAU'            => [8, 10, 13, 14, 15, 16] );
    $packet->edns->option( 'EXTENDED-ERROR' => {'INFO-CODE' => 123} );
    $packet->edns->option( '65023'          => {'BASE16' => '076578616d706c6500'} );

    $packet->edns->print;

        ;; {    "EDNS-VERSION": 0,
        ;;      "FLAGS":        "8000",
        ;;      "RCODE":        0,
        ;;      "UDPSIZE":      1232,
        ;;      "OPTIONS"       : [
        ;;              { "NSID": "7261776279746573" },
        ;;              { "TCP-KEEPALIVE": 200 },
        ;;              { "DAU": [ 8, 10, 13, 14, 15, 16 ] },
        ;;              { "EXTENDED-ERROR": { "INFO-CODE": 123, "EXTRA-TEXT": "" } },
        ;;              { "65023": { "BASE16": "076578616d706c6500" } } ]
        ;;      }

DESCRIPTION
EDNS OPT pseudo resource record.

The OPT record supports EDNS protocol extensions and is not intended to be created, accessed or modified directly by user applications.

All EDNS features are performed indirectly by operations on the objects returned by the $packet->header and $packet->edns creator methods. The underlying mechanisms are, or should be, entirely hidden from the user.

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.

  version
        $version = $packet->edns->version;

The version of EDNS supported by this OPT record.

  UDPsize
        $size = $packet->edns->UDPsize;
        $packet->edns->UDPsize($size);

UDPsize() advertises the maximum size (octets) of UDP packet that can be reassembled in the network stack of the originating host.

  rcode
        $extended_rcode   = $packet->header->rcode;

The 12 bit extended RCODE. The most significant 8 bits are obtained from the OPT record. The least significant 4 bits reside in the packet header.

  flags
        $do = $packet->header->do;
        $packet->header->do(1);

        $edns_flags = $packet->edns->flags;

16 bit field containing EDNS extended header flags.

  options, option
        my @option = $packet->edns->options;

When called in a list context, options() returns a list of option codes found in the OPT record.

        my $octets = $packet->edns->option('COOKIE');
        my $base16 = unpack 'H*', $octets;

        $packet->edns->option( 'COOKIE' => {'OPTION-DATA' => $octets} );
        $packet->edns->option( '10'     => {'BASE16'      => $base16} );

When called in a scalar context with a single argument, option() returns the uninterpreted octet string corresponding to the specified option. The method returns undef if the option is absent.

Options can be added or replaced by providing the (name => value) pair. The option is deleted if the value is undefined.

When called in a list context with a single argument, option() returns a structured representation of the option value.

For example:

        my ($structure) = $packet->edns->option('DAU');
        my @algorithms  = @$structure;

        my ($structure) = $packet->edns->option(15);
        my $info_code   = $$structure{'INFO-CODE'};
        my $extra_text  = $$structure{'EXTRA-TEXT'};

Similar forms of array or hash syntax may be used to construct the option value:

        $packet->edns->option( 'DAU' => [8, 10, 13, 14, 15, 16] );

        $packet->edns->option( 'EXTENDED-ERROR' => {'INFO-CODE'  => 123,
                                                    'EXTRA-TEXT' => ""} );

COPYRIGHT
Copyright (c)2001,2002 RIPE NCC. Author Olaf M. Kolkman.

Portions Copyright (c)2012,2017-2022 Dick Franks.

All rights reserved.

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

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 original copyright notices appear in all copies and that both 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, Net::DNS, Net::DNS::RR, RFC6891 <https://tools.ietf.org/html/rfc6891>, RFC3225 <https://tools.ietf.org/html/rfc3225>