Net::DNS::Packet(3) User Contributed Perl Documentation Net::DNS::Packet(3)NAMENet::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);
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 error string will only be defined if the packet object is
undefined (i.e., couldn't be 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 ques‐
tion section of the packet.
In dynamic update packets, this section is known as "zone" and speci‐
fies the zone to be updated.
answer, pre, prerequisite
@answer = $packet->answer;
Returns a list of "Net::DNS::RR" objects representing the answer sec‐
tion of the packet.
In dynamic update packets, this section is known as "pre" or "prerequi‐
site" 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 speci‐
fies the RRs or RRsets to be added or delted.
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 simi‐
lar 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-cre‐
ated 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 name‐
server. User-created packets will return undef for this method (use
"length $packet->data" instead).
push
$packet->push(pre => $rr);
$packet->push(update => $rr);
$packet->push(additional => $rr);
$packet->push(update => $rr1, $rr2, $rr3);
$packet->push(update => @rr);
Adds RRs to the specified section of the packet.
unique_push
$packet->unique_push(pre => $rr);
$packet->unique_push(update => $rr);
$packet->unique_push(additional => $rr);
$packet->unique_push(update => $rr1, $rr2, $rr3);
$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.
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", $offset);
Returns a domain name compressed for a particular packet object, to be
stored beginning at the given offset within the packet data. The name
will be added to a running list of compressed domain names for future
use.
dn_expand
use Net::DNS::Packetqw(dn_expand);
($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, 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);
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 fol‐
lowing 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);
You shouldn't modify a packet after signing it; otherwise authentica‐
tion will probably fail.
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.
COPYRIGHT
Copyright (c) 1997-2002 Michael Fuhr.
Portions Copyright (c) 2002-2004 Chris Reinhardt.
Portions Copyright (c) 2002-2005 Olaf Kolkman
All rights reserved. This program is free software; you may redis‐
tribute it and/or modify it under the same terms as Perl itself.
SEE ALSOperl(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
perl v5.8.8 2006-09-18 Net::DNS::Packet(3)
