Provided by: libnet-dns-perl_0.68-1.2build1_amd64 
NAME
Net::DNS::Packet - DNS protocol packet
SYNOPSIS
use Net::DNS::Packet;
$packet = new Net::DNS::Packet('example.com', 'MX', 'IN');
$resolver->send($packet);
DESCRIPTION
A "Net::DNS::Packet" object represents a DNS protocol packet.
METHODS
new
$packet = new Net::DNS::Packet('example.com');
$packet = new Net::DNS::Packet('example.com', 'MX', 'IN');
$packet = new Net::DNS::Packet();
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 called with an empty argument list, "new" creates an empty packet.
$packet = new Net::DNS::Packet(\$data);
$packet = new Net::DNS::Packet(\$data, 1); # set debugging
($packet, $err) = new Net::DNS::Packet(\$data);
If passed a reference to a scalar containing DNS packet data, "new" creates a packet
object by decoding the data. The optional second argument can be passed to turn on
debugging output.
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).
data
$data = $packet->data;
Returns the packet data in binary format, suitable for sending to a nameserver.
header
$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.
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 could not 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, 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