How to block a particular id from a socketCAN virtual network?

Question

I have a virtual socketCAN network. How do I block a particular ID from being sent on the network?

Answer 1

If a node is connected to a CAN bus, at the lowest level it cannot be prevented from sending any message externally.

However, there are 3 things that can be done:

1. Add a gateway - a device that separates the bus into multiple small buses and passes messages from each sub-buses to the others, it does not prevent any node from sending a message, but it will not pass it to the others. This solution have a few clear drawbacks - it requires a separate device with multiple CAN interfaces (up to the number of nodes on the bus), it adds a delay for each message, and it renders the ACK bit unusable.

2. Apply filters for the received messages in each node. Again, this will not prevent sending the message, but will drop the load on the nodes. Most CAN controllers have hardware support for filtering by ID or a bit mask of ID.

3. There are some CAN controllers that can block the sending of messages, again, this will require adding such controller and setting it up for each node in the CAN bus.