#!/usr/bin/perl -w
use strict;

my $fname = "ip.header";

open(FILE,$fname) or die $!;
binmode(FILE);

#read the first 32 bits 
read(FILE, my $foo, 4);
my $ver  = unpack "b4", $foo;
my $hlen = unpack "b4", $foo;
my $tos  = unpack "b8", $foo;
my $len  = unpack "n", $foo;

print "Ver = $ver, hlen = $hlen, tos = $tos, len = $len\n";

close FILE;