#!/usr/bin/perl -w
use strict;
use Net::Pcap;
use NetPacket::Ethernet;
use NetPacket::IP;
use NetPacket::TCP;

my $err;
my $dev = $ARGV[0];
my $object;

$object = Net::Pcap::open_offline($dev, \$err);
unless (defined $object) {
    die 'Unable to create packet capture on device ', $dev, ' - ', $err;
}


Net::Pcap::loop($object, -1, \&callback_function, '');
Net::Pcap::close($object);

sub callback_function {
  my ($user_data,$header,$packet) =@_;
  my $ether_data = NetPacket::Ethernet::strip($packet);
  my $ip = NetPacket::IP->decode($ether_data);
  my $tcp = NetPacket::TCP->decode($ip->{'data'});
  print
    $ip->{'src_ip'}, ":", $tcp->{'src_port'}, " -> ",
    $ip->{'dest_ip'}, ":", $tcp->{'dest_port'}, "\n";
}