IBus Gateway

OpenBM-Gateway is a linux daemon running in the background and acting as a gateway between BMW's IBus and local clients connected over a network TCP stack. In this case an IBus interface is connected to the PC's serial port. The interface must support CTS line. Hence some hardware collision detection, or at least a simple bit comparator must be implemented. This function is provided for example by the  TH3122 ic, which I am also using in this project.

The software exists as a Debian package for simple installation in my own small repository. In order to install it, either download it directly from the repository or add the repository address into the list of repository servers on your system. Currently there is only Debian packages available. The package consists of only one executable file.

The repository where to find the openbm-gateway package is (or download it  here):

deb http://deb.tevs.eu/ binary/

For information about parameters use

openbm-gateway -h

Features

• low CPU and memory usage (one thread per client + 3 server threads)
• forward IBus messages to connected clients over TCP/IPv4 and vice versa
• retransmit messages on collision
• completely asynchronous (receive and send messages over IBus and TCP/IP without blocking or intercepting)
• can act as a simple IBus logger
• code is actually platform independent (except of some extensions I had to made for  boost's asio library). So there is a possibility to implement this on Windows too.

IBus logger functionality

The daemon can also act as a simple IBus logger. This can be usefull if you just want to log ibus messages passend on the bus. In order to run the daemon as simple logger execute it as

openbm-gateway -l 4 -f ibus.log

Which will protocol ibus actions to the ibus.log file. The log file will look like this:

...
2010-Jul-20 10:07:00.767817: C0 04 68 32 11 8F
2010-Jul-20 10:07:00.891897: C0 04 68 32 11 8F
2010-Jul-20 10:07:00.928066: C0 04 68 32 10 8E
2010-Jul-20 10:07:00.943753: C0 04 68 32 10 8E
2010-Jul-20 10:07:01.116929: C0 03 68 01 AA
2010-Jul-20 10:07:01.140001: 68 04 BF 02 00 D1
...

Note there is currently no analysis going on, just a simple logging.

TCP/IP protocol

In order to be able to connect to the gateway server we have to make sure that server and client speaks the same language. The low-level protocol used for communication between the server (OpenBM-Gateway) and any client is TCP. On top of this a simple, really simple protocol is used to understand sent messages. Here is a small overview over the protocol:

Header:

	Ident:	src dst len x priority x x 1 2 3 4 5 6 7 8
	Byte:

Data:

	Ident:	data 1 ... len
	Byte:

...in work...

Server

...in work...

Client

...in work...

FAQ

...in work...

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