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#!/usr/bin/perl
#
# $Id: EthernetPacket.pm,v 1.3 2001/07/02 22:10:00 levine Exp $
#
# Copyright (C) 2001 James D. Levine (jdl@vinecorp.com)
#
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.
#
####################################################################
use NWatch::Packet;
use strict;
####################################################################
#
# ethernet packet
#
# Raw device packet, expects MAC addresses first but not preample
# data.
#
####################################################################
package NWatch::ethernet_packet;
@NWatch::ethernet_packet::ISA = qw( NWatch::packet );
sub protocol_name { "ethernet"; }
sub new
{
my( $type, $data ) = @_;
# init from base class
my $self = NWatch::packet::new( $type, $data );
# unpack fields
my $to = substr( $data, 0, 6 );
my $from = substr( $data, 6, 6 );
my $protocol = unpack "x12n", $data;
my $payload = substr( $data, 14, length( $data ) - 14 );
# make fields persistent
$self->set( "from", $from );
$self->set( "to", $to );
$self->set( "protocol", $protocol );
$self->set( "payload", $payload );
# for any known protocols, stack a packet instance on top
# check proto ID
# if known, set next to a new instance of proto with payload
# for now, protocols are hard-coded
# print "epk: proto $protocol \n";
if( $protocol == 2048 ) # IPv4
{
$self->next( new NWatch::ipv4_packet( $payload ) );
}
$self;
}
sub format_addr
{
my( $self, $a ) = @_;
return sprintf "%02x:%02x:%02x:%02x:%02x:%02x", unpack( "CCCCCC", $a );
}
1;
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