If you're installing the snap to run alongside the rest of the ROS software, on the Jackal's SBC, the snap should "just work" and be able to publish and subscribe to topics available from the Jackal by connecting to the Jackal's rosmaster. Snaps don't operate in a nested/NAT'd network namespace, you just need to make sure the snap uses the network
and network-bind
plugs to be able to properly access the network under confinement and it sees your host's network interface just like any other application.
If for some reason the Jackal uses a non-standard port for rosmaster, you can change where the snap connects by defining the catkin-ros-master-uri
option in the snapcraft.yaml's catkin part.
I'm unfamiliar with the Jackal. Are you going to be installing the snap on the same machine as the rest of the ROS software? Or another that is on the same network?
I plan to install the snap on the Jackals SBC, which runs the rest of the ROS software.