I have a local Linux machine (L), with a network interface (eth0) connected to (currently) only one device (D).
L/eth0 only has an ipv6 link local address. D also only has an ipv6 link local address.
Client software on L discovers D's link local address by sending a custom multicast packet over eth0. The response contain the device link local address as well as some configuration information. From there it communicates with the device using various UDP or TCP port.
My goal is to be able to use the device from a remote machine (R). The remote machine being most likely a Linux docker container running on some host - although it could be a native macOS or other.
That means running both the discovery protocol and communicate with the device. I definitely cannot modify software on the device, and cannot modify most of the client software running on the local Linux or remote machine (Limited modification could possibly be requested)
My idea was to somehow create a virtual interface on the remote machine, that would remotely be bridged to the the local machine, so that the multicast discovery works from the remote, and so that I can just connect to D link local address from the remote.
I'm not sure which tool(s) I should be using. I'm googling various things about VPN and tunnel, TUN/TAP interfaces, bridges, VETH, VLAN, etc... but I'm having trouble connecting the dots here... I have no budget for this, so I'm looking for open source tools, or just something I can cobble up together with common tools.
Thanks
