NAME
Net::DNS::ToolKit::RR::NS - Resource Record Handler
SYNOPSIS
DO NOT use Net::DNS::ToolKit::RR::NS
DO NOT require Net::DNS::ToolKit::RR::NS
Net::DNS::ToolKit::RR::NS 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,
$nsdname) = $get->NS(\$buffer,$offset);
Note: the $get->NS method is normally called
via: @stuff = $get->next(\$buffer,$offset);
($newoff,@dnptrs)=$put->NS(\$buffer,$offset,\@dnptrs,
$name,$type,$class,$ttl,$nsdname);
$NAME,$TYPE,$CLASS,$TTL,$rdlength,$NSDNAME)
= $parse->NS($name,$type,$class,$ttl,$rdlength,
$nsdname);DESCRIPTION
Net::DNS::ToolKit::RR:NS appends an NS resource record to a DNS packet under construction, recovers an NS 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.
3.3.11. NS RDATA format
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
/ NSDNAME /
/ /
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
where:
NSDNAME A <domain-name> which specifies a host which should be
authoritative for the specified class and domain.NS records cause both the usual additional section processing to locate a type A record, and, when used in a referral, a special search of the zone in which they reside for glue information.
The NS RR states that the named host should be expected to have a zone starting at owner name of the specified class. Note that the class may not indicate the protocol family which should be used to communicate with the host, although it is typically a strong hint. For example, hosts which are name servers for either Internet (IN) or Hesiod (HS) class information are normally queried using IN class protocols.
@stuff = $get->NS(\$buffer,$offset);
Get the contents of the resource record. USE: @stuff = $get->next(\$buffer,$offset); where: @stuff = ( $newoff $name,$type,$class,$ttl,$rdlength, $nsdname );All except the last item, $nsdname, is provided by the class loader, Net::DNS::ToolKit::RR. The code in this method knows how to retrieve $nsdname.
input: pointer to buffer, offset into buffer returns: offset to next resource, @common RR elements, NS Domain Name($newoff,@dnptrs)=$put->NS(\$buffer,$offset,\@dnptrs, $name,$type,$class,$ttl,$nsdname);
Append an NS record to $buffer.
where @common = ( $name,$type,$class,$ttl);The method will insert the $rdlength and $nsdname, then pass through 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 $rdlength.
input: pointer to buffer, offset (normally end of buffer), pointer to compressed name array, @common RR elements, NS Domain Name output: offset to next RR, new compressed name pointer array, or empty list () on error.(@COMMON,$NSDNAME) = $parse->NS(@common,$nsdname);
Converts binary/numeric field data into human readable form. The common RR elements are supplied by the class loader, Net::DNS::ToolKit::RR. For NS RR's, this returns $nsdname terminated with '.'
input: NS Domain Name returns: NS Domain Name.
DEPENDENCIES
Net::DNS::ToolKit
Net::DNS::CodesEXPORT
noneAUTHOR
Michael Robinton <michael@bizsystems.com>
COPYRIGHT
Copyright 2003, Michael Robinton <michael@bizsystems.com>
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
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 the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
See also:
Net::DNS::Codes(3), Net::DNS::ToolKit(3)