Net::DNS::Packet - phpMan

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NAME
    Net::DNS::Packet - DNS protocol packet

SYNOPSIS
        use Net::DNS::Packet;

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

        $reply = $resolver->send( $query );

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

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

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

    If passed a domain, type, and class, new() creates a Net::DNS::Packet
    object which is suitable for making a DNS query for the specified
    information. The type and class may be omitted; they default to A and
    IN.

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

        $packet = Net::DNS::Packet->decode( \$data );
        $packet = Net::DNS::Packet->decode( \$data, 1 );    # debug
        $packet = Net::DNS::Packet->new( \$data ... );

    If passed a reference to a scalar containing DNS packet data, a new
    packet object is created by decoding the data. The optional second
    boolean argument enables debugging output.

    Returns undef if unable to create a packet object.

    Decoding errors, including data corruption and truncation, are collected
    in the $@ ($EVAL_ERROR) variable.

        ( $packet, $length ) = Net::DNS::Packet->decode( \$data );

    If called in array context, returns a packet object and the number of
    octets successfully decoded.

    Note that the number of RRs in each section of the packet may differ
    from the corresponding header value if the data has been truncated or
    corrupted during transmission.

  data
        $data = $packet->data;
        $data = $packet->data( $size );

    Returns the packet data in binary format, suitable for sending as a
    query or update request to a nameserver.

    Truncation may be specified using a non-zero optional size argument.

  header
        $header = $packet->header;

    Constructor method which returns a Net::DNS::Header object which
    represents the header section of the packet.

  edns
        $edns    = $packet->edns;
        $version = $edns->version;
        $UDPsize = $edns->size;

    Auxiliary function which provides access to the EDNS protocol extension
    OPT RR.

  reply
        $reply = $query->reply( $UDPmax );

    Constructor method which returns a new reply packet.

    The optional UDPsize argument is the maximum UDP packet size which can
    be reassembled by the local network stack, and is advertised in response
    to an EDNS query.

  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 DNS 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 entire packet to the currently selected output filehandle
    using the master file format mandated by RFC1035.

  string
        print $packet->string;

    Returns a string representation of the packet.

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

    Returns the IP address from which this packet was received. This method
    will return undef for user-created packets.

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

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

  push
        $ancount = $packet->push( prereq => $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.

    Section names may be abbreviated to the first three characters.

  unique_push
        $ancount = $packet->unique_push( prereq => $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
    are not already present in the same section.

    Returns the number of resource records in the specified section.

    Section names may be abbreviated to the first three characters.

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

    Removes a single RR from the specified section of the packet.

  sign_tsig
        $query = Net::DNS::Packet->new( 'www.example.com', 'A' );

        $query->sign_tsig(
                    'Khmac-sha512.example.+165+01018.private',
                    fudge => 60
                    );

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

        $reply->verify( $query ) || die $reply->verifyerr;

    Attaches a TSIG resource record object, which will be used to sign the
    packet (see RFC 2845).

    The TSIG record can be customised by optional additional arguments to
    sign_tsig() or by calling the appropriate Net::DNS::RR::TSIG methods.

    If you wish to create a TSIG record using a non-standard algorithm, you
    will have to create it yourself. In all cases, the TSIG name must
    uniquely identify the key shared between the parties, and the algorithm
    name must identify the signing function to be used with the specified
    key.

        $tsig = Net::DNS::RR->new(
                    name            => 'tsig.example',
                    type            => 'TSIG',
                    algorithm       => 'custom-algorithm',
                    key             => '<base64 key text>',
                    sig_function    => sub {
                                              my ($key, $data) = @_;
                                                    ...
                                            }
                    );

        $query->sign_tsig( $tsig );

    The historical simplified syntax is still available, but additional
    options can not be specified.

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

    The response to an inbound request is signed by presenting the request
    in place of the key parameter.

        $response = $request->reply;
        $response->sign_tsig( $request, @options );

    Multi-packet transactions are signed by chaining the sign_tsig() calls
    together as follows:

        $opaque  =  $packet1->sign_tsig( 'Kexample.+165+13281.private' );
        $opaque  =  $packet2->sign_tsig( $opaque );
                    $packet3->sign_tsig( $opaque );

    The opaque intermediate object references returned during multi-packet
    signing are not intended to be accessed by the end-user application. Any
    such access is expressly forbidden.

    Note that a TSIG record is added to every packet; this implementation
    does not support the suppressed signature scheme described in RFC2845.

  verify and verifyerr
        $packet->verify()           || die $packet->verifyerr;
        $reply->verify( $query )    || die $reply->verifyerr;

    Verify TSIG signature of packet or reply to the corresponding query.

        $opaque  =  $packet1->verify( $query ) || die $packet1->verifyerr;
        $opaque  =  $packet2->verify( $opaque );
        $verifed =  $packet3->verify( $opaque ) || die $packet3->verifyerr;

    The opaque intermediate object references returned during multi-packet
    verify() will be undefined (Boolean false) if verification fails. Access
    to the object itself, if it exists, is expressly forbidden. Testing at
    every stage may be omitted, which results in a BADSIG error on the final
    packet in the absence of more specific information.

  sign_sig0
    SIG0 support is provided through the Net::DNS::RR::SIG class. The
    requisite cryptographic components are not integrated into Net::DNS but
    reside in the Net::DNS::SEC distribution available from CPAN.

        $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');

    Execution will be terminated if Net::DNS::SEC is not available.

  verify SIG0
        $packet->verify( $keyrr )           || die $packet->verifyerr;
        $packet->verify( [$keyrr, ...] )    || die $packet->verifyerr;

    Verify SIG0 packet signature against one or more specified KEY RRs.

  sigrr
        $sigrr = $packet->sigrr() || die 'unsigned packet';

    The sigrr method returns the signature RR from a signed packet or
    undefined if the signature is absent.

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

    The smallest length limit that is honoured is 512 octets.

COPYRIGHT
    Copyright (c)1997-2000 Michael Fuhr.

    Portions Copyright (c)2002-2004 Chris Reinhardt.

    Portions Copyright (c)2002-2009 Olaf Kolkman

    Portions Copyright (c)2007-2019 Dick Franks

    All rights reserved.

LICENSE
    Permission to use, copy, modify, and distribute this software and its
    documentation for any purpose and without fee is hereby granted,
    provided that the original copyright notices appear in all copies and
    that both copyright notice and this permission notice appear in
    supporting documentation, and that the name of the author not be used in
    advertising or publicity pertaining to distribution of the software
    without specific prior written permission.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

SEE ALSO
    perl, Net::DNS, Net::DNS::Update, Net::DNS::Header, Net::DNS::Question,
    Net::DNS::RR, Net::DNS::RR::TSIG, RFC1035 Section 4.1, RFC2136 Section
    2, RFC2845