icmpv4.pm

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   $self->[$__type]     = $type;
   $self->[$__code]     = $code;
   $self->[$__checksum] = $checksum;
   $self->[$__payload]  = $payload;

   # unpack specific ICMPv4 types
   my $sub = $unpackTypes->{$self->[$__type]} || \&_decodeError;
   my $href = $self->$sub or return undef;

   $self->$_($href->{$_}) for keys %$href;

   #爌ayload has been handled by previous chunk of code
   $self->[$__payload] = undef;

   1;
}

sub computeChecksums {
   my $self = shift;

   my $sub = $packTypes->{$self->[$__type]} || \&_decodeError;
   my $raw = $self->$sub or return undef;

   if (my $data = $self->[$__data]) {
      $raw .= $self->SUPER::pack('a*', $data)
         or return undef;
   }

   my $packed = $self->SUPER::pack('CCn', $self->[$__type], $self->[$__code], 0)
      or return undef;

   $self->[$__checksum] = inetChecksum($packed.$raw);

   1;
}

sub encapsulate { NP_LAYER_NONE }

sub print {
   my $self = shift;

   my $i = $self->is;
   my $l = $self->layer;
   my $buf = sprintf
      "$l:+$i: type:%d  code:%d  checksum:0x%.4x  size:%d",
         $self->type,
         $self->code,
         $self->checksum,
         $self->getLength,
   ;

   if ($self->data) {
      $buf .= sprintf("\n$l: $i: dataLength:%d  data:%s",
                      $self->getDataLength,
                      $self->SUPER::unpack('H*', $self->data))
         or return undef;
   }

   $buf;
}

#
# Helpers
#

sub _isType                { shift->[$__type] == shift()                 }
sub isTypeEchoRequest      { shift->_isType(NP_ICMPv4_TYPE_ECHO_REQUEST) }
sub isTypeEchoReply        { shift->_isType(NP_ICMPv4_TYPE_ECHO_REPLY)   }
sub isTypeTimestampRequest {
   shift->_isType(NP_ICMPv4_TYPE_TIMESTAMP_REQUEST);
}
sub isTypeTimestampReply {
   shift->_isType(NP_ICMPv4_TYPE_TIMESTAMP_REPLY);
}
sub isTypeInformationRequest {
   shift->_isType(NP_ICMPv4_TYPE_INFORMATION_REQUEST);
}
sub isTypeInformationReply {
   shift->_isType(NP_ICMPv4_TYPE_INFORMATION_REPLY);
}
sub isTypeAddressMaskRequest {
   shift->_isType(NP_ICMPv4_TYPE_ADDRESS_MASK_REQUEST);
}
sub isTypeAddressMaskReply {
   shift->_isType(NP_ICMPv4_TYPE_ADDRESS_MASK_REPLY);
}
sub isTypeDestinationUnreachable {
   shift->_isType(NP_ICMPv4_TYPE_DESTINATION_UNREACHABLE);
}

1;

__END__

=head1 NAME

Net::Packet::ICMPv4 - Internet Control Message Protocol v4 layer 4 object

=head1 SYNOPSIS

   use Net::Packet::ICMPv4;
   use Net::Packet::Consts qw(:icmpv4);

   # Build echo-request header
   my $echo = Net::Packet::ICMPv4->new(data => '0123456789');

   # Build information-request header
   my $info = Net::Packet::ICMPv4->new(
      type => NP_ICMPv4_TYPE_INFORMATION_REQUEST,
      data => '0123456789',
   );

   # Build address-mask request header
   my $mask = Net::Packet::ICMPv4->new(
      type => NP_ICMPv4_TYPE_ADDRESS_MASK_REQUEST,
      data => '0123456789',
   );

   # Build timestamp request header
   my $timestamp = Net::Packet::ICMPv4->new(
      type => NP_ICMPv4_TYPE_TIMESTAMP_REQUEST,
      data => '0123456789',
   );


   # Decode from network to create the object
   # Usually, you do not use this, it is used by Net::Packet::Frame
   my $decode = Net::Packet::ICMPv4->new(raw => $rawFromNetwork);

   print $echo->print, "\n";

=head1 DESCRIPTION

This modules implements the encoding and decoding of the ICMPv4 layer.

RFC: ftp://ftp.rfc-editor.org/in-notes/rfc792.txt

See also B<Net::Packet::Layer> and B<Net::Packet::Layer4> for other attributes a
nd methods.

=head1 ATTRIBUTES

=over 4

=item B<type>

=item B<code>

Type and code fields. See B<CONSTANTS>.

=item B<checksum>

The checksum of ICMPv4 header.

=item B<identifier>

Identification number.

=item B<sequenceNumber>

Sequence number.

=item B<originateTimestamp>

=item B<receiveTimestamp>

=item B<transmitTimestamp>

Three timestamps used by the B<NP_ICMPv4_TYPE_TIMESTAMP_REQUEST> message.

=item B<addressMask>

Used by the B<NP_ICMPv4_TYPE_ADDRESS_MASK_REQUEST> message.

=item B<gateway>

Used by the B<NP_ICMPv4_TYPE_REDIRECT> message.

=item B<unused>

Zero value field used in various ICMP messages.

=item B<error>

A pointer to a B<Net::Packet::Frame> object, usually set when an ICMP error message has been returned.

=item B<data>

Additionnal data can be added to an ICMP message, traditionnaly used in B<NP_ICMPv4_TYPE_ECHO_REQUEST>.

=back

=head1 METHODS

=over 4

=item B<new>

Object constructor. You can pass attributes that will overwrite default ones. Default values:

type:               NP_ICMPv4_TYPE_ECHO_REQUEST

code:               NP_ICMPv4_CODE_ZERO

checksum:           0

identifier:         getRandom16bitsInt()

sequenceNumber:     getRandom16bitsInt()

originateTimestamp: time()

receiveTimestamp:   0

transmitTimestamp:  0

addressMask:        0

gateway:            "127.0.0.1"

unused:             0

data:               ""

=item B<recv>

Will search for a matching replies in B<framesSorted> or B<frames> from a B<Net::Packet::Dump> object.

=item B<getDataLength>

Returns the length in bytes of B<data> attribute.

=item B<pack>

Packs all attributes into a raw format, in order to inject to network. Returns 1 on success, undef otherwise.

=item B<unpack>

Unpacks raw data from network and stores attributes into the object. Returns 1 on success, undef otherwise.

=item B<isTypeEchoRequest>

=item B<isTypeEchoReply>

=item B<isTypeTimestampRequest>

=item B<isTypeTimestampReply>

=item B<isTypeInformationRequest>

=item B<isTypeInformationReply>

=item B<isTypeAddressMaskRequest>

=item B<isTypeAddressMaskReply>

=item B<isTypeDestinationUnreachable>

Returns 1 if the B<type> attribute is of specified type.

=back

=head1 CONSTANTS

Load them: use Net::Packet::Consts qw(:icmpv4);

=over 4

=item B<NP_ICMPv4_CODE_ZERO>

ICMP code zero, used by various ICMP messages.

=item B<NP_ICMPv4_TYPE_DESTINATION_UNREACHABLE>

=item B<NP_ICMPv4_CODE_NETWORK>

=item B<NP_ICMPv4_CODE_HOST>

=item B<NP_ICMPv4_CODE_PROTOCOL>

=item B<NP_ICMPv4_CODE_PORT>

=item B<NP_ICMPv4_CODE_FRAGMENTATION_NEEDED>

=item B<NP_ICMPv4_CODE_SOURCE_ROUTE_FAILED>

Destination unreachable type, with possible code numbers.

=item B<NP_ICMPv4_TYPE_REDIRECT>

=item B<NP_ICMPv4_CODE_FOR_NETWORK>

=item B<NP_ICMPv4_CODE_FOR_HOST>

=item B<NP_ICMPv4_CODE_FOR_TOS_AND_NETWORK>

=item B<NP_ICMPv4_CODE_FOR_TOS_AND_HOST>

Redirect type message, with possible code numbers.

=item B<NP_ICMPv4_TYPE_TIME_EXCEEDED>

=item B<NP_ICMPv4_CODE_TTL_IN_TRANSIT>

=item B<NP_ICMPv4_CODE_FRAGMENT_REASSEMBLY>

Time exceeded message, with possible code numbers.

=item B<NP_ICMPv4_TYPE_ECHO_REQUEST>

=item B<NP_ICMPv4_TYPE_ECHO_REPLY>

=item B<NP_ICMPv4_TYPE_TIMESTAMP_REQUEST>

=item B<NP_ICMPv4_TYPE_TIMESTAMP_REPLY>

=item B<NP_ICMPv4_TYPE_INFORMATION_REQUEST>

=item B<NP_ICMPv4_TYPE_INFORMATION_REPLY>

=item B<NP_ICMPv4_TYPE_ADDRESS_MASK_REQUEST>

=item B<NP_ICMPv4_TYPE_ADDRESS_MASK_REPLY>

Other request/reply ICMP messages types.

=back

=head1 AUTHOR

Patrice E<lt>GomoRE<gt> Auffret

=head1 COPYRIGHT AND LICENSE

Copyright (c) 2004-2006, Patrice E<lt>GomoRE<gt> Auffret

You may distribute this module under the terms of the Artistic license.
See LICENSE.Artistic file in the source distribution archive.

=head1 RELATED MODULES

L<NetPacket>, L<Net::RawIP>, L<Net::RawSock>

=cut