Net::DNS::ToolKit::RR::MX - Resource Record Handler
DO NOT use Net::DNS::ToolKit::RR::MX DO NOT require Net::DNS::ToolKit::RR::MX Net::DNS::ToolKit::RR::MX is autoloaded by class Net::DNS::ToolKit::RR and its methods are instantiated in a 'special' manner. use Net::DNS::ToolKit::RR; ($get,$put,$parse) = new Net::DNS::ToolKit::RR; ($newoff,$name,$type,$class,$ttl,$rdlength, $pref,$mxdname) = $get->MX(\$buffer,$offset); Note: the $get->MX method is normally called via: @stuff = $get->next(\$buffer,$offset); ($newoff,@dnptrs)=$put->MX(\$buffer,$offset,\@dnptrs, $name,$type,$class,$ttl,$pref,$mxdname); $NAME,$TYPE,$CLASS,$TTL,$rdlength,$pref,$MXDNAME) = $parse->MX($name,$type,$class,$ttl,$rdlength, $pref,$mxdname);
Net::DNS::ToolKit::RR:MX appends an MX resource record to a DNS packet under construction, recovers an MX resource record from a packet being decoded, and converts the numeric/binary portions of the resource record to human readable form.
Description from RFC1035.txt 3.2.1. Format All RRs have the same top level format shown below: 1 1 1 1 1 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NAME | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | TYPE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | CLASS | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | TTL | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | RDLENGTH | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--| | RDATA | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ NAME an owner name, i.e., the name of the node to which this resource record pertains. TYPE two octets containing one of the RR TYPE codes. CLASS two octets containing one of the RR CLASS codes. TTL a 32 bit signed integer that specifies the time interval that the resource record may be cached before the source of the information should again be consulted. Zero values are interpreted to mean that the RR can only be used for the transaction in progress, and should not be cached. For example, SOA records are always distributed with a zero TTL to prohibit caching. Zero values can also be used for extremely volatile data. RDLENGTH an unsigned 16 bit integer that specifies the length in octets of the RDATA field. RDATA a variable length string of octets that describes the resource. The format of this information varies according to the TYPE and CLASS of the resource record. 3.3.9. MX RDATA format +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | PREFERENCE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ / EXCHANGE / / / +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ where: PREFERENCE A 16 bit integer which specifies the preference given to this RR among others at the same owner. Lower values are preferred. EXCHANGE A <domain-name> which specifies a host willing to act as a mail exchange for the owner name.
MX records cause type A additional section processing for the host specified by EXCHANGE. The use of MX RRs is explained in detail in [RFC-974].
@stuff = $get->MX(\$buffer,$offset);
Get the contents of the resource record. USE: @stuff = $get->next(\$buffer,$offset); where: @stuff = ( $newoff $name,$type,$class,$ttl,$rdlength, $pref,$mxdname );
All except the last two items, $pref, $mxdname, are provided by the class loader, Net::DNS::ToolKit::RR. The code in this method knows how to retrieve $pref, $mxdname.
input: pointer to buffer, offset into buffer returns: offset to next resource, @common RR elements, preference, mail host domain name
($newoff,@dnptrs)=$put->MX(\$buffer,$offset,\@dnptrs, $name,$type,$class,$ttl,$pref,$mxdname);
Append an MX record to $buffer.
where @common = ( $name,$type,$class,$ttl);
The method will insert the $rdlength, $pref and $mxdname, then return the updated pointer to the array of compressed names
The class loader, Net::DNS::ToolKit::RR, inserts the @common elements and returns updated @dnptrs. This module knows how to insert its RDATA and calculate the $rdlength.
input: pointer to buffer, offset (normally end of buffer), pointer to compressed name array, @common RR elements, preference, mail host domain name output: offset to next RR, new compressed name pointer array, or empty list () on error.
(@COMMON,$pref,$MXDNAME) = $parse->MX(@common,$pref,$mxdname);
Converts binary/numeric field data into human readable form. The common RR elements are supplied by the class loader, Net::DNS::ToolKit::RR. For MX RR's, this returns $mxdname terminated with '.'
input: preference, MX Domain Name returns: preference MX Domain Name.
Net::DNS::ToolKit Net::DNS::Codes
none
Michael Robinton <michael@bizsystems.com>
Copyright 2003 - 2011, Michael Robinton <michael@bizsystems.com>
All rights reserved.
This program is free software; you can redistribute it and/or modify it under the terms of either:
a) the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version, or b) the "Artistic License" which comes with this distribution.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See either the GNU General Public License or the Artistic License for more details.
You should have received a copy of the Artistic License with this distribution, in the file named "Artistic". If not, I'll be glad to provide one.
You should also have received a copy of the GNU General Public License along with this program in the file named "Copying". If not, write to the
Free Software Foundation, Inc. 59 Temple Place, Suite 330 Boston, MA 02111-1307, USA
or visit their web page on the internet at:
http://www.gnu.org/copyleft/gpl.html.
Net::DNS::Codes(3), Net::DNS::ToolKit(3)
To install Net::DNS::ToolKit, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Net::DNS::ToolKit
CPAN shell
perl -MCPAN -e shell install Net::DNS::ToolKit
For more information on module installation, please visit the detailed CPAN module installation guide.