Linux Unwired [Electronic resources] نسخه متنی

10.5 Mapping Wi-Fi Networks with Kismet

We introduced Chapter 3 as a powerful network scanner. You can also
use it in conjunction with GPSd to map out the locations of Wi-Fi
networks. (For the basics of getting Kismet running, see Chapter 3.) Once you have Kismet and GPSd up and
running, you can make them work together.

To map networks with Kismet and GPSd:

(Optional.) Load any modules needed for the serial port
you're using for the GPS:

$ sudo modprobe pl2303
$ dmesg | grep tty   
ttyS00 at 0x03f8 (irq = 4) is a 16550A
ttyS02 at 0x03e8 (irq = 4) is a 16550A
usbserial.c: PL-2303 converter now attached to ttyUSB0 
(or usb/tts/0 for devfs)

Start GPSd, specifying the serial port with -p and
the speed with -s:

$ sudo gpsd -D9 -p /dev/ttyUSB0 -s 4800

Telnet to GPSd and use p until you have a reliable
fix; you can disconnect when you are done:

$ telnet localhost 2947
Trying 127.0.0.1...
Connected to debian.
Escape character is '^]'.
p
GPSD,P=0.000000 0.000000
p
GPSD,P=41.485882 -71.524841
^]
telnet> q
Connection closed.

Launch Kismet with the -g (GPS) switch and specify
the hostname and port that GPSd is listening on:

$ sudo kismet -g localhost:2947

Go for a drive. Press Q when you are done with the drive to terminate
Kismet.

When you shut down
Kismet, it writes its log files. Check
the logtemplate setting in
kismet.conf to see where it puts its log files:

logtemplate=/var/log/kismet/%n-%d-%i.%l

Kismet writes several log files in the
logtemplate directory (I
starts at 1 and increments for each time you run Kismet on a given
day):

Kismet-<MMM-DD-YYYY>-I.csv

Kismet log in semicolon-separated fields, one line per entry. The
first entry contains the field names.

Kismet-<MMM-DD-YYYY>-I.dump

Kismet log in a pcap(3) format suitable for
loading under Ethereal (http://www.ethereal.com).

Kismet-<MMM-DD-YYYY>-I.gps

Kismet log in a format designed to be read by the
gpsmap utility, which is included with the
Kismet distribution.

Kismet-<MMM-DD-YYYY>-I.network

A human-readable dump of the networks that Kismet encountered.

Kismet-<MMM-DD-YYYY>-I.xml

Kismet log in an XML format.

When you're done with Kismet, you must reassociate your Wi-Fi card with the network. This can sometimes be done by restarting PCMCIA card services or removing and reinserting the card, but it resulted in a kernel panic in some of our tests. Our workaround was to use a second network card for network connectivity and let Kismet have its way with the Prism-based card on wlan0.

To generate a map, run
gpsmap on the .gps log
file. See the gpsmap manpage for all the drawing
and mapping options. If you choose to use a downloaded map (the
default), you must be online. Figure 10-8 shows a
map generated by the following command:

$ gpsmap -S3 -p /var/log/kismet/Kismet-Feb-16-2004-5.gps

The -S option specifies which map server to use (0
= MapBlast;1 = MapPoint;2 = Terraserver; 3= Tiger Census). If you
have trouble with one, try another (Tiger is loosely maintained by
the Census Bureau and is not up 100 percent of the time). Use
-p to show power levels or -e
to plot simply the locations of the hotspots on the map (see the
gpsmap manpage for more options).

Figure 10-8. Wi-Fi power levels in the Kingston, Rhode Island area