Sniff airport traffic and map MAC addresses to a last.fm username

tunewatch.py

#!/usr/bin/env python

import subprocess
import sys
import re
import urllib

# Mapping of local MAC addresses to last.fm usernames
MAC_ADDRESSES = {
    '00:00:00:00:00:00': 'lastfm_username',
}
# only really works when you have a dedicated base station for speakers that
# isn't also serving internets
AIRPORT_MAC = ['00:00:00:00:00:00', '00:00:00:00:00:01'] # add as many receivers as you have
INTERFACE = 'en1' # might need changing, check your ifconfig for the wifi interface

PACKET_PATTERN = re.compile('.*SA:([^\s]+).*')
def map_line_to_mac_address(line):
    m = PACKET_PATTERN.match(line)
    if m:
        mac_address = m.group(1)
        return mac_address
    return None

def sniff_network():
    tcpdump = [
        'tcpdump',
        '-n', # Don't resolve hosts/ports to names
        '-i', INTERFACE, # Listen on wifi interface
        '-y', 'IEEE802_11', # Use the 802.11 data link layer
        '-I', # Monitor mode, listen in on all network traffic
        '-e', # Include packet headers, so we can parse out mac addresses
        # '-vvv', # verbose
        'wlan', 'dst', 'host', ' or '.join(AIRPORT_MAC) # BPF filter where destination host is one of the Airport MACs
    ]
    print ' '.join(tcpdump)
    proc = subprocess.Popen(' '.join(tcpdump), shell=True, stdout=subprocess.PIPE)
    process_lines(proc)

def process_lines(proc):
    now_playing = None
    now_playing_dj = None
    try:
        while True:
            line = proc.stdout.readline()
            mac_address = map_line_to_mac_address(line)
            if mac_address and mac_address != now_playing:
                try:
                    if mac_address in MAC_ADDRESSES:
                        dj = MAC_ADDRESSES[mac_address]
                        if dj != now_playing_dj:
                            # print '\n', line,
                            print 'New DJ: %s' % dj
                            # post to a web server somewhere or whatever
                            now_playing_dj = dj
                    else:
                        # print '\n', line,
                        print 'Unknown MAC address: %s' % mac_address
                    sys.stdout.flush()
                    now_playing = mac_address
                except IOError as exc:
                    # update call failed, try again
                    print 'Error!', exc
    except KeyboardInterrupt:
        pass

if __name__ == '__main__':
    sniff_network()