lan_traffic

#!/usr/bin/env perl
use Net::Pcap;
use NetPacket::Ethernet;
use NetPacket::IP;
use Time::HiRes qw(time);
use Net::Subnet;
use strict;
use warnings;

my $err;
my $traffic = {};
my $traffic2 = {};
my $last_time = time;

my $is_rfc1918 = subnet_matcher qw(
        10.0.0.0/16
        192.168.0.0/16
    );

my $dev = $ARGV[0] or die "Usage: lan_traffic interface \n";

$dev = Net::Pcap::lookupdev(\$err);
die "Unable to determine network device for monitoring - $err\n" if defined $err;

my ($address, $netmask);
Net::Pcap::lookupnet($dev, \$address, \$netmask, \$err);
die "Unable to look up device information for $dev - $err\n" if defined $err;

my $object;
$object = Net::Pcap::open_live($dev, 1500, 0, 0, \$err);
die "Unable to create packet capture on device $dev - $err\n" if defined $err;


print "...\n";
Net::Pcap::loop($object, -1, \&syn_packets, '') or die "Unable to perform packet capture on device $dev\n";
Net::Pcap::close($object);


sub format_size
{
    my $s = shift;
    return sprintf("%.2fB", $s) if $s < 1024;
    return sprintf("%.2fKB", $s / 1024) if $s < 1024 * 1024;
    return sprintf("%.2fMB", $s / 1024 / 1024);
}

sub show_data
{
    my $time = time;
    my $delta = $time - $last_time;
    return if $delta < 1;
    print "===\n";
    my $total = 0;
    for my $ip (keys %$traffic)
    {
        my $len = $traffic->{$ip};
        my $last_len = $traffic2->{$ip} || 0;
        my $speed = ($len - $last_len) / $delta;
        next if $speed <= 0;
        $total += $speed;
        print "$ip " . format_size($speed) . "/s\n";
    }
    printf("Total speed : %s\n", format_size($total));
    $traffic2 = $traffic;
    $traffic = {};
    $last_time = $time;
}

sub syn_packets {
    my ($user_data, $header, $packet) = @_;
    my $ether_data = NetPacket::Ethernet::strip($packet);
    my $ip = NetPacket::IP->decode($ether_data);
    my $src_ip = $ip->{src_ip};
    my $dest_ip = $ip->{dest_ip};
    return if($is_rfc1918->($src_ip) && $is_rfc1918->($dest_ip));
    $traffic->{$src_ip} += $ip->{len} if $is_rfc1918->($src_ip);
    $traffic->{$dest_ip} += $ip->{len} if $is_rfc1918->($dest_ip);
    show_data();
}