/ 
Net-DNS-0.66_02
River stage three • 109 direct dependents • 566 total dependents
/ Net::DNS::Packet

NAME

Net::DNS::Packet - DNS packet object class

SYNOPSIS

use Net::DNS::Packet;

DESCRIPTION

A Net::DNS::Packet object represents a DNS packet.

METHODS

new

$packet = Net::DNS::Packet->new("example.com");
$packet = Net::DNS::Packet->new("example.com", "MX", "IN");

$packet = Net::DNS::Packet->new(\$data);
$packet = Net::DNS::Packet->new(\$data, 1);  # set debugging

($packet, $err) = Net::DNS::Packet->new(\$data);

$packet = Net::DNS::Packet->new();

If passed a domain, type, and class, new creates a packet object appropriate for making a DNS query for the requested information. The type and class can be omitted; they default to A and IN.

If passed a reference to a scalar containing DNS packet data, new creates a packet object from that data. A second argument can be passed to turn on debugging output for packet parsing.

If called in array context, returns a packet object and an error string. The content of the error string is unspecified if the packet object was successfully created.

Returns undef if unable to create a packet object (e.g., if the packet data is truncated).

If called with an empty argument list, new creates an empty packet.

data

$data = $packet->data;

Returns the packet data in binary format, suitable for sending to a nameserver.

$header = $packet->header;

Returns a Net::DNS::Header object representing the header section of the packet.

question, zone

@question = $packet->question;

Returns a list of Net::DNS::Question objects representing the question section of the packet.

In dynamic update packets, this section is known as zone and specifies the zone to be updated.

answer, pre, prerequisite

@answer = $packet->answer;

Returns a list of Net::DNS::RR objects representing the answer section of the packet.

In dynamic update packets, this section is known as pre or prerequisite and specifies the RRs or RRsets which must or must not preexist.

authority, update

@authority = $packet->authority;

Returns a list of Net::DNS::RR objects representing the authority section of the packet.

In dynamic update packets, this section is known as update and specifies the RRs or RRsets to be added or deleted.

additional

@additional = $packet->additional;

Returns a list of Net::DNS::RR objects representing the additional section of the packet.

print

$packet->print;

Prints the packet data on the standard output in an ASCII format similar to that used in DNS zone files.

string

print $packet->string;

Returns a string representation of the packet.

answerfrom

print "packet received from ", $packet->answerfrom, "\n";

Returns the IP address from which we received this packet. User-created packets will return undef for this method.

answersize

print "packet size: ", $packet->answersize, " bytes\n";

Returns the size of the packet in bytes as it was received from a nameserver. User-created packets will return undef for this method (use length $packet->data instead).

push

$ancount = $packet->push(pre        => $rr);
$nscount = $packet->push(update     => $rr);
$arcount = $packet->push(additional => $rr);

$nscount = $packet->push(update => $rr1, $rr2, $rr3);
$nscount = $packet->push(update => @rr);

Adds RRs to the specified section of the packet.

Returns the number of resource records in the specified section.

unique_push

$ancount = $packet->unique_push(pre        => $rr);
$nscount = $packet->unique_push(update     => $rr);
$arcount = $packet->unique_push(additional => $rr);

$nscount = $packet->unique_push(update => $rr1, $rr2, $rr3);
$nscount = $packet->unique_push(update => @rr);

Adds RRs to the specified section of the packet provided that the RRs do not already exist in the packet.

Returns the number of resource records in the specified section.

safe_push

A deprecated name for unique_push().

pop

my $rr = $packet->pop("pre");
my $rr = $packet->pop("update");
my $rr = $packet->pop("additional");
my $rr = $packet->pop("question");

Removes RRs from the specified section of the packet.

dn_comp

$compname = $packet->dn_comp("foo.example.com", $offset);

Returns a domain name compressed for a particular packet object, to be stored beginning at the given offset within the packet data. The name will be added to a running list of compressed domain names for future use.

dn_expand

use Net::DNS::Packet qw(dn_expand);
($name, $nextoffset) = dn_expand(\$data, $offset);

($name, $nextoffset) = Net::DNS::Packet::dn_expand(\$data, $offset);

Expands the domain name stored at a particular location in a DNS packet. The first argument is a reference to a scalar containing the packet data. The second argument is the offset within the packet where the (possibly compressed) domain name is stored.

Returns the domain name and the offset of the next location in the packet.

Returns (undef) if the domain name couldn't be expanded.

sign_tsig

$key_name = "tsig-key";
$key      = "awwLOtRfpGE+rRKF2+DEiw==";

$update = Net::DNS::Update->new("example.com");
$update->push("update", rr_add("foo.example.com A 10.1.2.3"));

$update->sign_tsig($key_name, $key);

$response = $res->send($update);

Attaches a TSIG resource record object containing a key, which will be used to signs a packet with a TSIG resource record (see RFC 2845). Uses the following defaults:

algorithm   = HMAC-MD5.SIG-ALG.REG.INT
time_signed = current time
fudge       = 300 seconds

If you wish to customize the TSIG record, you'll have to create it yourself and call the appropriate Net::DNS::RR::TSIG methods. The following example creates a TSIG record and sets the fudge to 60 seconds:

$key_name = "tsig-key";
$key      = "awwLOtRfpGE+rRKF2+DEiw==";

$tsig = Net::DNS::RR->new("$key_name TSIG $key");
$tsig->fudge(60);

$query = Net::DNS::Packet->new("www.example.com");
$query->sign_tsig($tsig);

$response = $res->send($query);

sign_sig0

SIG0 support is provided through the Net::DNS::RR::SIG class. This class is not part of the default Net::DNS distribution but resides in the Net::DNS::SEC distribution.

$update = Net::DNS::Update->new("example.com");
$update->push("update", rr_add("foo.example.com A 10.1.2.3"));
$update->sign_sig0("Kexample.com+003+25317.private");

SIG0 support is experimental see Net::DNS::RR::SIG for details.

The method will call Carp::croak() if Net::DNS::RR::SIG cannot be found.

truncate

The truncate method takes a maximum length as argument and then tries to truncate the packet an set the TC bit according to the rules of RFC2181 Section 9.

The minimum maximum length that is honored is 512 octets.

COPYRIGHT

Copyright (c) 1997-2002 Michael Fuhr.

Portions Copyright (c) 2002-2004 Chris Reinhardt.

Portions Copyright (c) 2002-2009 Olaf Kolkman

Portions Copyright (c) 2007-2008 Dick Franks

All rights reserved. This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

perl(1), Net::DNS, Net::DNS::Resolver, Net::DNS::Update, Net::DNS::Header, Net::DNS::Question, Net::DNS::RR, RFC 1035 Section 4.1, RFC 2136 Section 2, RFC 2845