NAME
Net::DNS::ToolKit::RR - Resource Record class loader
SYNOPSIS
(
$get
,
$put
,
$parse
) = new Net::DNS::ToolKit::RR;
or
(
$get
,
$put
,
$parse
) = Net::DNS::ToolKit::RR->new;
retrieve the
next
record (type unknown)
(
$newoff
,
$name
,
$type
,
$class
,
$ttl
,
$rdlength
,
$rdata
,...)
=
$get
->
next
(\
$buffer
,
$offset
);
parse the current record (type in input fields)
(
$name
,
$typeTXT
,
$classTXT
,
$ttlTXT
,
$rdlength
,
$RDATA
,...)
=
$parse
->RR(
$name
,
$type
,
$class
,
$ttl
,
$rdlength
,
$rdata
,...);
(
$newoff
,
@dnptrs
)=
$put
->XYZ(\
$buffer
,
$offset
,\
@dnptrs
,
$name
,
$type
,
$class
,
$ttl
,
$rdata
,...);
The
'get'
and
'parse'
operations can also be done
by specific record type...
(
$newoff
,
$name
,
$type
,
$class
,
$ttl
,
$rdlength
,
$rdata
,...)
=
$get
->XYZ(\
$buffer
,
$offset
);
(
$name
,
$typeTXT
,
$classTXT
,
$ttlTXT
,
$rdlength
,
$RDATA
,...)
=
$parse
->XYZ(
$name
,
$type
,
$class
,
$ttl
,
$rdlength
,
$rdata
,...);
directly without calling
"new"
@output
=Net::DNS::ToolKit::RR::get->
next
(
@input
);
@output
=Net::DNS::ToolKit::RR::get->XYZ(
@input
);
@output
=Net::DNS::ToolKit::RR::put->XYZ(
@input
);
@output
=Net::DNS::ToolKit::RR::parse->RR(
@input
);
@output
=Net::DNS::ToolKit::RR::parse->XYZ(
@input
);
The Question section is a special case:
(
$newoff
,
$name
,type,class) =
$get
->Question(\
$buffer
,
$offset
);
(
$newoff
,
@dnptrs
) =
$put
->Question(\
$buffer
,
$offset
,
$name
,
$type
,
$class
,\
@dnptrs
);
(
$name
,
$typeTXT
,
$classTXT
) =
$parse
->Question(
$name
,
$type
,
$class
);
ALTERNATE PUT METHOD SYNOPSIS
An alternate method for put is available for class specific submissions. This eliminates the need to specify TYPE and CLASS when doing a put. The generic form of a put command using this method is shown below but NOT detailed in the method descriptions.
(
$get
,
$put
,
$parse
) = new Net::DNS::ToolKit::RR(class_type);
or
(
$get
,
$put
,
$parse
) = Net::DNS::ToolKit::RR->new(C_IN);
The generic form of a put
operation then becomes:
(
$newoff
,
@dnptrs
)=
$put
->XYZ(\
$buffer
,
$offset
,\
@dnptrs
,
$name
,
$ttl
,
$rdate
,...)
The only class currently supported at this time is C_IN.
NOTE: the use of this alternate method changes the number of required arguments to ALL put RR operations. These changes are NOT noted below in the method descriptions.
DESCRIPTION
Net::DNS::ToolKit::RR is the class loader for Resource Record classes. It provides an extensible wrapper for existing classes as well as the framework to easily add new RR classes. See: Net::DNS::ToolKit::RR::Template
From RFC 1035
3.2.1. Format
All RRs have the same top level
format
shown below:
1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| NAME |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TYPE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| CLASS |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TTL |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| RDLENGTH |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
| RDATA |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
NAME an owner name, i.e., the name of the node to which this
resource record pertains.
TYPE two octets containing one of the RR TYPE codes.
CLASS two octets containing one of the RR CLASS codes.
TTL a 32 bit signed integer that specifies the
time
interval
that the resource record may be cached
before
the source
of the information should again be consulted. Zero
values
are interpreted to mean that the RR can only be
used
for
the transaction in progress, and should not be
cached. For example, SOA records are always distributed
with
a zero TTL to prohibit caching. Zero
values
can
also be used
for
extremely volatile data.
RDLENGTH an unsigned 16 bit integer that specifies the
length
in octets of the RDATA field.
RDATA a variable
length
string of octets that describes the
resource. The
format
of this information varies
according to the TYPE and CLASS of the resource record.
($get,$put,$parse) = new Net::DNS::ToolKit::RR;
Retrieves the method pointers to get, put, and parse for Queston section and Resource Records of a particular type.
($newoff,@common,$rdata,...) = $get->next(\$buffer,$offset);
Get the next Resource Record.
input: pointer to buffer,
offset into buffer
returns: offset to
next
RR or section,
(items common to all RR's)
i.e.
$name
,
$type
,
$class
,
$ttl
,
$rdlength
,
$rdata
,....
for
this RR
or
undef
if
the RR is unsupported.
HERE IS THE OPPORTUNITY FOR YOU TO ADD TO THIS PACKAGE. If your RR of interest is not supported, see:
Net::DNS::ToolKit::RR::Template in:
.../Net/DNS/ToolKit/Template/Template.pm
Build the support for your Resource Record and submit it to CPAN as an extension to this package.
UN-IMPLEMENTED methods: $get->[unimplemented] returns a correct offset to the following RR, correct @common data and a single $rdata element containing a null ... "\0" to be precise. This works as either a numeric 0 (zero) or an end of string.
($newoff,@dnptrs)=$put->XYZ(\$buffer,$offset,\@dnptrs, $name,$type,$class,$ttl,$rdata,...);
Append a resource record of type XYZ to the current buffer. This is the generic form of a put.
input: pointer to buffer,
offset, [should be end of buffer]
pointer to compressed name array,
(items common to all RR's)
i.e.
$name
,
$type
,
$class
,
$ttl
,
$rdata
,....
for
this RR
in binary form
if
appropriate
returns: offset to end of RR,
new pointer array,
or empty list
if
the RR type is
unsupported
See: note above about writing new RR's
UN-IMPLEMENTED methods: $put->[unimplemented] fails miserably with a DIE statement identifying the offending method.
(@COMMON,$RDATA) = $parse->XYZ(@common,$rdata,...);
Convert non-printable and numeric data common to all records and the RR specific rdata into ascii text. In many cases this is a null operation. i.e. for a TXT record. However, for a RR of type A, the operation would be as follows:
EXAMPLE
Common:
name is already text.
type numeric to text
class numeric to text
ttl numeric to text
rdlength is a number
rdata RR specific conversion
Resource Record A returns $rdata containing a packed IPv4 network address. The parse operation would be:
input:
name foo.bar.com
type 1
class 1
ttl 123
rdlength 4
rdata a packed IPv4 address
output:
name foo.bar.com
type T_A
class C_IN
ttl 123
# 2m 3s
rdlength 4
rdata 192.168.20.40
The rdata conversion is implemented internally as:
$dotquad
= inet_ntoa(
$networkaddress
);
where
$dotquad
is a printable IP address like
192.168.20.55
UN-IMPLEMENTED methods: $parse->[unimplemented] returns correct @common elements insofar as the type and class are present in Net::DNS::Codes. Other elements are passed through unchanged. i.e. garbage-in, garbage-out.
($newoff,$name,type,class) = $get->Question(\$buffer,$offset);
Get the Question.
input: pointer to buffer,
offset
returns: domain name,
question type,
question class
($newoff,@dnptrs) = $put->Question(\$buffer,$offset, $name,$type,$class,\@dnptrs);
Append a question to the $buffer. Returns a new pointer array for compressed names and the offset to the next RR.
NOTE: it is up to the user to update the question count. See: put_qdcount
Since the question usually is the first record to be appended to the buffer, @dnptrs may be ommitted. See the details at dn_comp.
Usage: ($newoff,@dnptrs)=$put->Question(\$buffer,$offset, $name,$type,$class);
input: pointer to buffer,
offset into buffer,
domain name,
question type,
question class,
pointer to array of
previously compressed names,
returns: offset to
next
record,
updated array of offsets to
previous compressed names
($name,$typeTXT,$classTXT) = $parse->Question($name,$type,$class);
Convert non-printable and numeric data into ascii text.
input: domain name,
question type (numeric)
question class (numeric)
returns: domain name,
type TEXT,
class TEXT
DEPENDENCIES
Net::DNS::ToolKit
EXPORT
none
AUTHOR
Michael Robinton <michael@bizsystems.com>
COPYRIGHT
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:
See also:
Net::DNS::Codes(3), Net::DNS::ToolKit(3), Net::DNS::ToolKit::RR::Template(3)