Hi. I'm working on a project where I want to have the linux qemu guest communicate with another linux system via ethernet-over-usb (as far as the guest is concerned, as it will be using a usb network gadget). In this case the linux guest will be using a USB Device Controller (UDC) to drive its side of the connection, and the protocol will be, IIUC, CDC-ECM.
The modeling would basically look like: linux-guest <--> UDC-model <--> ?#1 <--> ?#2 <--> linux-host |<-------------------- QEMU -------------->| UDC-model will be working with CDC-ECM, but is there a use-case where we'd want "?#1" to be libslirp and "?#2" to be the host's IP network? Another use case is propagating CDC-ECM (or the USB packets in general) outside of QEMU such that it can be fed directly into the USB of the host (or remote host). Questions: Is this support in QEMU and if so got any pointers to source for existing examples? If not, any guidance on how to proceed? Of course we'd want this to not be a one-off. E.g., the code would be partitioned such that the UDC-model-independent-support would be available to other UDC models to use. Thus perhaps this falls under the scope of things like this? https://yhbt.net/lore/all/YFDo%2FoHikOEcXFcg@work-vm/ I'm new to all of this side of USB btw ...
