Cyphal network bridge & router PoC

This is a visual aid for https://forum.opencyphal.org/t/cyphal-udp-routing-over-multiple-networks/1657/7?u=pavel.kirienko

Currently we are using Cyphal/serial instead of Cyphal/UDP because the bridge relies on the transfer spoofing feature and it is at this moment not yet implemented for pycyphal.transport.udp.UDPTransport. It makes no difference though.

Preparation

1. Initialize vcan0 and vcan1 like:

modprobe can
modprobe can_raw
modprobe vcan
ip link add dev vcan0 type vcan
ip link set vcan0 mtu 72         # Enable CAN FD by configuring the MTU of 64+8
ip link set up vcan0

2. y co https://github.com/OpenCyphal/public_regulated_data_types/archive/refs/heads/master.zip
3. Open a few terminals and source env_vcan0.sh in some of them and env_vcan1.sh in others. These are the separate CAN network segments. Run some publishers/subscribers like:
   • On vcan0: y pub 1000:uavcan.primitive.scalar.integer64 '!$ n'
   • On vcan1: y sub 1000:uavcan.primitive.scalar.integer64
4. Observe that there is no traffic crossing the network segments as they are isolated.
5. Run y mon in each network segment to see the activity.

Bridge evaluation

1. Run bridge_serial_socketcan.orc.yaml. It will launch two bridges: vcan0 <-bridge-> serial <-bridge-> vcan1.
2. Observe that the subscriber now sees the data from the publisher.
3. Running a new instance of y sub 1000 or y pub 1000 whatever will show that type discovery is also working.

Router evaluation

1. Run router_serial_socketcan.orc.yaml. It will launch two routers: vcan0 <-router-> serial <-router-> vcan1.
2. Observe that the subscriber now sees the data from the publisher as if it was published by the nearest bridge (which is technically the case).
3. Running a new instance of y sub 1000 or y pub 1000 whatever will fail because the router does not have the registers containing the type information, and service transfers are not routed.