The original purpose of canny was to allow multiple machines to communicate with a CAN bus without the need for multiple CAN controllers. It was originally meant for development/evaluation and is NOT intended to be used in production environments. There are no security precautions taken to authenticate devices connecting from the IP-network, and messages are blindly forwarded without sanitizing their contents. It should go without saying that this is not meant to be used in an actual car or industrial control network.

There are two possible use-cases for canny:

• To connect IP-based machines to a CAN bus
• To connect two CAN buses over an IP network

How to use canny in these situations will be described in the following sections.

In the first case, canny can be started like this:

$ canny -p 1234

This way, canny will listen for incoming TCP connections on port 1234 and forward messages between all connected CAN buses and established TCP connections. However, messages received on one CAN bus will not be forwarded to another.

To connect two CAN buses over an IP network, start canny on two different machines like the following example.

Start a canny server on machine A (let's assume its IP is 10.0.0.1):

$ canny -p 1234

Then, start canny as a client on machine B:

$ canny -c 10.0.0.1 -p 1234

Now, messages received on any CAN interfaces on machine A will be forwarded to all CAN interfaces of machine B, and vice-versa. Again, messages will not be forwarded between different CAN interfaces of the same machine.

You do not have to tell canny what SocketCAN interfaces to use for sending and receiving messages to and from the connected CAN buses. Upon startup, canny will iterate over all network interfaces, looking for interfaces containing the string "can". This way, most common interfaces (e.g. can0, vcan0) will be automatically detected.

Canny is free software, distributed under the terms of the GNU GPLv3+. For further information, see the COPYING file.