#
# NetPacket::ICMP -Decode and encode ICMP (Internet Control Message
# Protocol) packets.
#
# Comments/suggestions to tpot@samba.org
#
# Encode and checksum by Stephanie Wehner <atrak@itsx.com>
#
# $Id: ICMP.pm,v 1.11 2001/07/29 23:45:00 tpot Exp $
#
package NetPacket::ICMP;
#
# Copyright (c) 2001 Tim Potter.
#
# This package is free software and is provided "as is" without express
# or implied warranty. It may be used, redistributed and/or modified
# under the terms of the Perl Artistic License (see
# http://www.perl.com/perl/misc/Artistic.html)
#
# Copyright (c) 1995,1996,1997,1998,1999 ANU and CSIRO on behalf of
# the participants in the CRC for Advanced Computational Systems
# ('ACSys').
#
# ACSys makes this software and all associated data and documentation
# ('Software') available free of charge. You may make copies of the
# Software but you must include all of this notice on any copy.
#
# The Software was developed for research purposes and ACSys does not
# warrant that it is error free or fit for any purpose. ACSys
# disclaims any liability for all claims, expenses, losses, damages
# and costs any user may incur as a result of using, copying or
# modifying the Software.
#
# Copyright (c) 2001 Stephanie Wehner
#
use strict;
use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
my $myclass;
BEGIN {
$myclass = __PACKAGE__;
$VERSION = "0.03";
}
sub Version () { "$myclass v$VERSION" }
BEGIN {
@ISA = qw(Exporter NetPacket);
# Items to export into callers namespace by default
# (move infrequently used names to @EXPORT_OK below)
@EXPORT = qw(
);
# Other items we are prepared to export if requested
@EXPORT_OK = qw(icmp_strip
ICMP_ECHOREPLY ICMP_UNREACH ICMP_SOURCEQUENCH
ICMP_REDIRECT ICMP_ECHO ICMP_ROUTERADVERT
ICMP_ROUTERSOLICIT ICMP_TIMXCEED ICMP_PARAMPROB
ICMP_TSTAMP ICMP_TSTAMPREPLY ICMP_IREQ ICMP_IREQREPLY
ICMP_MASREQ ICMP_MASKREPLY
);
# Tags:
%EXPORT_TAGS = (
ALL => [@EXPORT, @EXPORT_OK],
types => [qw(ICMP_ECHOREPLY ICMP_UNREACH ICMP_SOURCEQUENCH
ICMP_REDIRECT ICMP_ECHO ICMP_ROUTERADVERT
ICMP_ROUTERSOLICIT ICMP_TIMXCEED ICMP_PARAMPROB
ICMP_TSTAMP ICMP_TSTAMPREPLY ICMP_IREQ ICMP_IREQREPLY
ICMP_MASREQ ICMP_MASKREPLY)],
strip => [qw(icmp_strip)],
);
}
# ICMP Types
use constant ICMP_ECHOREPLY => 0;
use constant ICMP_UNREACH => 3;
use constant ICMP_SOURCEQUENCH => 4;
use constant ICMP_REDIRECT => 5;
use constant ICMP_ECHO => 8;
use constant ICMP_ROUTERADVERT => 9;
use constant ICMP_ROUTERSOLICIT => 10;
use constant ICMP_TIMXCEED => 11;
use constant ICMP_PARAMPROB => 12;
use constant ICMP_TSTAMP => 13;
use constant ICMP_TSTAMPREPLY => 14;
use constant ICMP_IREQ => 15;
use constant ICMP_IREQREPLY => 16;
use constant ICMP_MASKREQ => 17;
use constant ICMP_MASKREPLY => 18;
#
# Decode the packet
#
sub decode {
my $class = shift;
my($pkt, $parent, @rest) = @_;
my $self = {};
# Class fields
$self->{_parent} = $parent;
$self->{_frame} = $pkt;
# Decode ICMP packet
if (defined($pkt)) {
($self->{type}, $self->{code}, $self->{cksum}, $self->{data}) =
unpack("CCna*", $pkt);
}
# Return a blessed object
bless($self, $class);
return $self;
}
#
# Strip a packet of its header and return the data
#
undef &icmp_strip;
*icmpstrip = \&strip;
sub strip {
my ($pkt, @rest) = @_;
my $icmp_obj = decode($pkt);
return $icmp_obj->data;
}
#
# Encode a packet
#
sub encode {
my $self = shift;
my ($ip) = @_;
my ($packet);
# Checksum the packet
$self->checksum();
# Put the packet together
$packet = pack("CCna*", $self->{type}, $self->{code},
$self->{cksum}, $self->{data});
return($packet);
}
#
# Calculate ICMP checksum
sub checksum {
my $self = shift;
my ($ip) = @_;
my ($packet,$zero);
# Put the packet together for checksumming
$zero = 0;
$packet = pack("CCna*", $self->{type}, $self->{code},
$zero, $self->{data});
$self->{cksum} = NetPacket::htons(NetPacket::in_cksum($packet));
}
#
# Module initialisation
#
1;
# autoloaded methods go after the END token (&& pod) below
__END__
=head1 NAME
C<NetPacket::ICMP> - Assemble and disassemble ICMP (Internet Control
Message Protocol) packets.
=head1 SYNOPSIS
use NetPacket::ICMP;
$icmp_obj = NetPacket::ICMP->decode($raw_pkt);
$icmp_pkt = NetPacket::ICMP->encode();
$icmp_data = NetPacket::ICMP::strip($raw_pkt);
=head1 DESCRIPTION
C<NetPacket::ICMP> provides a set of routines for assembling and
disassembling packets using ICMP (Internet Control Message Protocol).
=head2 Methods
=over
=item C<NetPacket::ICMP-E<gt>decode([RAW PACKET])>
Decode the raw packet data given and return an object containing
instance data. This method will quite happily decode garbage input.
It is the responsibility of the programmer to ensure valid packet data
is passed to this method.
=item C<NetPacket::ICMP-E<gt>encode()>
Return an ICMP packet encoded with the instance data specified.
=back
=head2 Functions
=over
=item C<NetPacket::ICMP::strip([RAW PACKET])>
Return the encapsulated data (or payload) contained in the ICMP
packet.
=back
=head2 Instance data
The instance data for the C<NetPacket::ICMP> object consists of
the following fields.
=over
=item type
The ICMP message type of this packet.
=item code
The ICMP message code of this packet.
=item cksum
The checksum for this packet.
=item data
The encapsulated data (payload) for this packet.
=back
=head2 Exports
=over
=item default
none
=item exportable
Icmp message types:
ICMP_ECHOREPLY ICMP_UNREACH ICMP_SOURCEQUENCH
ICMP_REDIRECT ICMP_ECHO ICMP_ROUTERADVERT
ICMP_ROUTERSOLICIT ICMP_TIMXCEED ICMP_PARAMPROB
ICMP_TSTAMP ICMP_TSTAMPREPLY ICMP_IREQ ICMP_IREQREPLY
ICMP_MASREQ ICMP_MASKREPLY
=item tags
The following tags group together related exportable items.
=over
=item C<:strip>
Import the strip function C<icmp_strip>.
=item C<:ALL>
All the above exportable items.
=back
=back
=head1 EXAMPLE
=head1 TODO
=over
=item Create constants
=item Write example
=back
=head1 COPYRIGHT
Copyright (c) 2001 Tim Potter.
This package is free software and is provided "as is" without express
or implied warranty. It may be used, redistributed and/or modified
under the terms of the Perl Artistic License (see
http://www.perl.com/perl/misc/Artistic.html)
Copyright (c) 1995,1996,1997,1998,1999 ANU and CSIRO on behalf of
the participants in the CRC for Advanced Computational Systems
('ACSys').
ACSys makes this software and all associated data and documentation
('Software') available free of charge. You may make copies of the
Software but you must include all of this notice on any copy.
The Software was developed for research purposes and ACSys does not
warrant that it is error free or fit for any purpose. ACSys
disclaims any liability for all claims, expenses, losses, damages
and costs any user may incur as a result of using, copying or
modifying the Software.
=head1 AUTHOR
Tim Potter E<lt>tpot@samba.orgE<gt>
Stephanie Wehner E<lt>atrak@itsx.comE<gt>
=cut
# any real autoloaded methods go after this line