Net::Packet::CDP - Cisco Discovery Protocol layer 4 object

   use Net::Packet::Consts qw(:cdp);
   require Net::Packet::CDP;

   # Build a layer
   my $layer = Net::Packet::CDP->new(
      version  => 2,
      ttl      => 180,
      checksum => 0,
   );
   $layer->pack;

   print 'RAW: '.unpack('H*', $layer->raw)."\n";

   # Read a raw layer
   my $layer = Net::Packet::CDP->new(raw => $raw);

   print $layer->print."\n";
   print 'PAYLOAD: '.unpack('H*', $layer->payload)."\n"
      if $layer->payload;

#
# $Id: CDP.pm 1640 2009-11-09 17:58:27Z gomor $
#
package Net::Packet::CDP;
use strict;
use warnings;

require Net::Packet::Layer4;
our @ISA = qw(Net::Packet::Layer4);

use Net::Packet::Consts qw(:cdp :layer);
require Net::Packet::CDP::TypeDeviceId;
require Net::Packet::CDP::TypeAddresses;
require Net::Packet::CDP::TypePortId;
require Net::Packet::CDP::TypeCapabilities;
require Net::Packet::CDP::TypeSoftwareVersion;

our @AS = qw(
   version
   ttl
   checksum
   typeDeviceId
   typeAddresses
   typePortId
   typeCapabilities
   typeSoftwareVersion
);
__PACKAGE__->cgBuildIndices;
__PACKAGE__->cgBuildAccessorsScalar(\@AS);

no strict 'vars';

sub new {
   shift->SUPER::new(
      version  => 2,
      ttl      => 180,
      checksum => 0,
      @_,
   );
}

sub getLength { NP_CDP_HDR_LEN }

sub pack {
   my $self = shift;

   $self->[$__raw] = $self->SUPER::pack('CCn',
      $self->[$__version],
      $self->[$__ttl],
      $self->[$__checksum],
   ) or return undef;

   if ($self->[$__typeDeviceId]) {
      $self->[$__raw] .= $self->[$__typeDeviceId]->pack
         or return undef;
   }
   if ($self->[$__typeAddresses]) {
      $self->[$__raw] .= $self->[$__typeAddresses]->pack
         or return undef;
   }
   if ($self->[$__typePortId]) {
      $self->[$__raw] .= $self->[$__typePortId]->pack
         or return undef;
   }
   if ($self->[$__typeCapabilities]) {
      $self->[$__raw] .= $self->[$__typeCapabilities]->pack
         or return undef;
   }
   if ($self->[$__typeSoftwareVersion]) {
      $self->[$__raw] .= $self->[$__typeSoftwareVersion]->pack
         or return undef;
   }

   1;
}

sub unpack {
   my $self = shift;

   my ($version, $ttl, $checksum, $payload) =
      $self->SUPER::unpack('CCn a*', $self->[$__raw])
         or return undef;

   $self->[$__version]  = $version;
   $self->[$__ttl]      = $ttl;
   $self->[$__checksum] = $checksum;

   my $tail = CORE::unpack('H*', $payload);

   if ($tail =~ /^0001/) {
      my $type = Net::Packet::CDP::TypeDeviceId->new(raw => $payload);
      $self->[$__typeDeviceId] = $type;
      $payload = $type->payload;
      $tail    = CORE::unpack('H*', $payload);
   }
   if ($tail =~ /^0002/) {
      my $type = Net::Packet::CDP::TypeAddresses->new(raw => $payload);
      $self->[$__typeAddresses] = $type;
      $payload = $type->payload;
      $tail    = CORE::unpack('H*', $payload);
   }
   if ($tail =~ /^0003/) {
      my $type = Net::Packet::CDP::TypePortId->new(raw => $payload);
      $self->[$__typePortId] = $type;
      $payload = $type->payload;
      $tail    = CORE::unpack('H*', $payload);
   }
   if ($tail =~ /^0004/) {
      my $type = Net::Packet::CDP::TypeCapabilities->new(raw => $payload);
      $self->[$__typeCapabilities] = $type;
      $payload = $type->payload;
      $tail    = CORE::unpack('H*', $payload);
   }
   if ($tail =~ /^0005/) {
      my $type = Net::Packet::CDP::TypeSoftwareVersion->new(raw => $payload);
      $self->[$__typeSoftwareVersion] = $type;
      $payload = $type->payload;
      $tail    = CORE::unpack('H*', $payload);
   }

   $self->[$__payload]  = $payload;

   1;
}

sub encapsulate {
   my $types = {
      NP_LAYER_NONE() => NP_LAYER_NONE(),
   };

   $types->{NP_LAYER_NONE()} || NP_LAYER_UNKNOWN();
}

sub print {
   my $self = shift;

   my $buf = '';

   my $l = $self->layer;
   my $i = $self->is;
   $buf .= sprintf "$l:+$i: version:%d  ttl:%d  checksum:0x%04x",
      $self->[$__version], $self->[$__ttl], $self->[$__checksum];

   if ($self->[$__typeDeviceId]) {
      $buf .= "\n".$self->[$__typeDeviceId]->print;
   }
   if ($self->[$__typeAddresses]) {
      $buf .= "\n".$self->[$__typeAddresses]->print;
   }
   if ($self->[$__typePortId]) {
      $buf .= "\n".$self->[$__typePortId]->print;
   }
   if ($self->[$__typeCapabilities]) {
      $buf .= "\n".$self->[$__typeCapabilities]->print;
   }
   if ($self->[$__typeSoftwareVersion]) {
      $buf .= "\n".$self->[$__typeSoftwareVersion]->print;
   }

   $buf;
}

1;

__END__