NAME

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

SYNOPSIS

           use Net::DNS;
           $packet = new Net::DNS::Packet( ... );

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

           $packet->edns->size(1280);                  # UDP payload size

           $packet->edns->option( COOKIE => $cookie );

           $packet->edns->print;

           ;; EDNS version 0
           ;;      flags:  8000
           ;;      rcode:  NOERROR
           ;;      size:   1280
           ;;      option: COOKIE  => ( 7261776279746573 )

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 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 = $rr->version;

       The version of EDNS used by this OPT record.

   size
               $size = $packet->edns->size;
               $more = $packet->edns->size(1280);

       size() 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;
               $incomplete_rcode = $packet->edns->rcode;

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

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

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

       16 bit field containing EDNS extended header flags.

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

               $octets = $packet->edns->option($option_code);

               $packet->edns->option( COOKIE => $cookie );
               $packet->edns->option( 10     => $cookie );

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

       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
       specified option is absent.

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

       When option() is called in a list context with a single argument, the returned array
       provides a structured interpretation appropriate to the specified option.

       For the example above:

               %hash = $packet->edns->option(10);

               {
                   'CLIENT-COOKIE' => 'rawbytes',
                   'SERVER-COOKIE' => undef
               };

       For some options, an array is more appropriate:

               @algorithms = $packet->edns->option(6);

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

               $packet->edns->option( DHU => [1, 2, 4] );
               $packet->edns->option( 6   => (1, 2, 4) );

               $packet->edns->option( COOKIE => {'CLIENT-COOKIE' => $cookie} );
               $packet->edns->option( 10     => ('CLIENT-COOKIE' => $cookie) );

COPYRIGHT

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

       Portions Copyright (c)2012,2017 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 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, Net::DNS, Net::DNS::RR, RFC6891, RFC3225