Jkx@home » wrt http://www.larsen-b.com Titanium Exposé Fri, 31 Oct 2025 02:15:37 +0000 en-US hourly 1 http://wordpress.org/?v=3.5 Arpwatch on WRT54G http://www.larsen-b.com/Article/203.html http://www.larsen-b.com/Article/203.html#comments Thu, 12 May 2005 15:22:32 +0000 admin Continue reading →]]> While running my access point in public mode, i want to know when people log in. This can be a good way to find intruders too, but not my purpose.
I decided to run arpwatch on my linksys access point, but this is not so easy ..

1) Mail

First you need to have sendmail on the WRT. So install mini_sendmail. Add a file /usr/sbin/sendmail that contains:

#!/bin/sh
/usr/sbin/mini_sendmail -t -sIP_of_your_mail_relay

Check that it ‘s working..

2) Arpwatch

Run arpwatch on the WRT throught this script:

#!/bin/sh
IFNAME=$(nvram get wifi_ifname)

case $1 in
start)
touch /tmp/arpwatch.dat
arpwatch -f /tmp/arpwatch.dat -i $IFNAME
;;
stop)
killall arpwatch
;;
*)
echo "usage: $0 (start|stop)"
exit 1
esac

exit $?

3) Check

Wait a bit, connect to your wifi, look at your email on the gateway. (root@gw) you will see something like this:

From: root@openwrt.local.net
Subject: new station

hostname: <unknown>
ip address: 192.168.2.1
ethernet address: 0:f:66:c7:b5:b1
ethernet vendor: <unknown>
timestamp: Tuesday, January 18, 2000 14:34:01 +0000

Enjoy :)

]]> http://www.larsen-b.com/Article/203.html/feed 3 Python on a WRT54GS ? http://www.larsen-b.com/Article/183.html http://www.larsen-b.com/Article/183.html#comments Wed, 01 Dec 2004 18:57:23 +0000 admin Continue reading →]]> Ok, I ‘ve been off for a little time right now. The main reason, is that I spend some time hacking my new Wireless access point: WRT54GS.

I spend a lot of time tweaking the config to use this in client mode with dhcp thought the WAN port and other nuts. I spend some time on http://www.brest-wireless.org too. But this is the mean reason of this post :)

Some people would think I’m a crazy boy but this is perhaps true. I managed to cross-compile python for the WRT. If you ask me why, I would simply answer that there is a lot of network stuff on a WRT that can be writen in a couple of python lines: dhcpd, dns cache, http server, dynamic pages rendering, dynamic firewall rules (check out last posts ..), diagnostics tools .. That’s it, now we need to figure out if this is do-able :)

WRT use a broadcom misp processor, so we need:

  • to install a cross-compile environnement: Not to hard.
  • tweak the python Makefile to use this, a little more funny but it works.
  • first tests..

As you can imagine, this doesn’t work at all :) The main issue is that current python use g++ (2.3), and the WRT only came with uClib, not the uClib++. After this wrong experience, I decided to take a old python: 1.5.2 . This one only needs gcc fine ! Ok, let’s see the result:

telnet host50
Trying 192.168.1.50...
Connected to host50.soif.fr.
Escape character is '^]'.

BusyBox v1.00 (2004.11.20-09:17+0000) Built-in shell (ash)
Enter 'help' for a list of built-in commands.

@OpenWrt:/# /tmp/python
Could not find platform independent libraries <prefix>
Could not find platform dependent libraries <exec_prefix>
Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
'import exceptions' failed; use -v for traceback
Warning!  Falling back to string-based exceptions
'import site' failed; use -v for traceback
Python 1.5.2 (#2, Nov 21 2004, 05:52:09)  [GCC 3.2.3 with Broadcom modifications] on linux2
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> import sys
>>> import os
Traceback (innermost last):
File "<stdin>", line 1, in ?
ImportError: No module named os
>>>

As you can see on this little capture, some parts of the interpreter works, but other don’t. The main issue is the build of modules. Something goes wrong at the link (ld), and I was unable to fully compile this.

Anyway this is not a big issue, because right now, I don’t think python 1.5.2 is a great challenger anyways. For people interested the python exec does 1.6Mo but a WRT54GS has 6Mo of free ROM.

I would really enjoy to hear your comments about your experience w/ ‘embeded python’. I guess that java has this kind of cross-compile issue too, but java is ready for cellphones, or other stuffs. Why not python ?

]]> http://www.larsen-b.com/Article/183.html/feed 5 Alternative Firmware for the WRT54GS http://www.larsen-b.com/Article/182.html http://www.larsen-b.com/Article/182.html#comments Sat, 20 Nov 2004 12:10:51 +0000 admin Continue reading →]]> Ok, yes, I bought a new WRT54GS, this works quite fine. I ‘m able to do what i want with that stuff. I will explain in a future post how to use this stuff in a secure way without using WEP.

Here is the list of firmware to use on this little box:

  • The Official one (pretty nice, but doesn’t allow telnet over device )
  • Sveasoft (the infamous weaked GPL one)
  • EWRT (sveasoft + nocat -> hotspot)
  • Wifi-box (hum not tested yet)
  • openWRT (minimal setup without http)
  • MeshBoxKit (openWRT + OLSR, special for Meshing)

Look at Seattle wiki on WRT for more infos. Do you use another one ?

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