package Net::DNS::ToolKit::RR::A; #use 5.006; use strict; #use warnings; use vars qw($VERSION @ISA); require Net::DNS::ToolKit::RR::Template; $VERSION = do { my @r = (q$Revision: 0.02 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r }; @ISA = qw(Net::DNS::ToolKit::RR::Template); *get = \&Net::DNS::ToolKit::RR::Template::get; *put = \&Net::DNS::ToolKit::RR::Template::put; *parse = \&Net::DNS::ToolKit::RR::Template::parse; =cut 1; __END__ =head1 NAME Net::DNS::ToolKit::RR::A - Resource Record Handler =head1 SYNOPSIS DO NOT use Net::DNS::ToolKit::RR::A DO NOT require Net::DNS::ToolKit::RR::A Net::DNS::ToolKit::RR::A is autoloaded by class Net::DNS::ToolKit::RR and its methods are instantiated in a 'special' manner. use Net::DNS::ToolKit::RR; ($get,$put,$parse) = new Net::DNS::ToolKit::RR; ($newoff,$name,$type,$class,$ttl,$rdlength, $netaddr) = $get->A(\$buffer,$offset); Note: the $get->A method is normally called via: @stuff = $get->next(\$buffer,$offset); ($newoff,@dnptrs)=$put->A(\$buffer,$offset,\@dnptrs, $name,$type,$class,$ttl,$netaddr); $name,$TYPE,$CLASS,$TTL,$rdlength,$IPaddr) = $parse->A($name,$type,$class,$ttl,$rdlength, $netaddr); =head1 DESCRIPTION B appends an A resource record to a DNS packet under construction, recovers an A 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. 3.4.1. A RDATA format +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ADDRESS | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ where: ADDRESS A 32 bit Internet address. Hosts that have multiple Internet addresses will have multiple A records. =over 4 =item * @stuff = $get->A(\$buffer,$offset); Get the contents of the resource record. USE: @stuff = $get->next(\$buffer,$offset); where: @stuff = ( $newoff $name,$type,$class,$ttl,$rdlength, $netaddr ); All except the last item, B<$netaddr>, is provided by the class loader, B. The code in this method knows how to retrieve B<$netaddr>. input: pointer to buffer, offset into buffer returns: offset to next resource, @common RR elements, packed IPv4 address in network order NOTE: convert IPv4 address to dot quad text using Net::DNS::ToolKit::inet_ntoa =item * ($newoff,@dnptrs)=$put->A(\$buffer,$offset,\@dnptrs, @common,$netaddr); Append an A record to $buffer. where @common = $name,$type,$class,$ttl The B method will insert the $rdlength and $netaddr, then pass through the updated pointer to the array of compressed names The class loader, B, inserts the @common elements and returns updated @dnptrs. This module knows how to insert its RDATA and calculate the $rdlength. input: pointer to buffer, offset (normally end of buffer), pointer to compressed name array, @common RR elements, packed IPv4 address in network order output: offset to next RR, new compressed name pointer array, or empty list () on error. NOTE: convert dot quad text to a packed network address using Net::DNS::ToolKit::inet_aton =item * (@COMMON,$RDATA) = $parse->A(@common,$rdata,...); Converts binary/numeric field data into human readable form. The common RR elements are supplied by the class loader, B. This module knows how to parse its RDATA. EXAMPLE Common is: name,$type,$class,$ttl,$rdlength 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 B 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 =back =head1 DEPENDENCIES Net::DNS::ToolKit Net::DNS::ToolKit::RR::Template Net::DNS::Codes =head1 EXPORT none =head1 AUTHOR Michael Robinton =head1 COPYRIGHT Copyright 2003, Michael Robinton 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. =head1 See also: Net::DNS::Codes(3), Net::DNS::ToolKit(3), Net::DNS::ToolKit::RR::Template(3) =cut 1;