#!/usr/bin/perl -w

use Net::Pcap;


my $err = '';
my $dev = pcap_lookupdev(\$err);  # find a device

# open the device for live listening
my $pcap = pcap_open_live($dev, 1024, 1, 0, \$err);

# loop over next 10 packets
pcap_loop($pcap, 10, \&process_packet, "just for the demo");

# close the device
pcap_close($pcap);

sub process_packet {
    my($user_data, $header, $packet) = @_;
    # do something ...
}