add virtual USB Network support

[s-light]

add support for virtual USB-Network interface

• RNDIS
• Ethernet Control Model (ECM)
• Network Control Model (NCM)
  sometimes also called USB CDC NCM

usage

• the CP device shows as Network card to a host (computer / phone / tablet)
• CP device has build in DHCP server - so host-device gets ip address

now we could experiment with network-based things, without the need of a real LAN or Wifi network...

link collection

• original adafruit forum topic
• tinyusb example
• rp2040 example implementation
• USB.org NCM document

[s-light]

i would like to experiment with this thing..
but have the feeling that for my available spare time it is to difficult to get all the different needed things together for me..
currently i have no idea of how i could at least start to include / experiment with this in the circuitpython code-tree...

@tannewt pointed at some possible directions in the forum topic:

• integrate the example
• get this to work as socketpool thing (i think somehow with this )
• this way it could be used by all other already available network things.

[samblenny]

Have you evaluated whether a Raspberry Pi Zero or a Beagle Board with Blinka might be a better fit for your USB to DMX bridge idea? IIRC, the PocketBeagle 2 in particular is designed to work well in USB gadget mode, but I think the Pi Zero can do it too. I don't know if Blinka works on the PocketBeagle.

My impression of what you're describing for adding USB virtual network interface support to CircuitPython is that, while it would be really cool, it would probably be a fairly heavy lift. With a Linux SBC that supports USB gadget mode, it might be a lot less work to get something up and running.

[s-light]

that is a good point!
it is really less work to do! (just use ola as basis..)
would be a good fit for this particular project idea.

my first main idea was to use CP as i like it a lot and it is easier to stay at on framework..
(i try to do all hobby project ideas in CP these days ;-) )
and i thought - there is already all this network things in there - could be a very easy thing to add...

main difference of uC and soc boards for practical usage - at least with my experiments ~8year ago -
the cold start-up time of os-based soc boards is much longer than an ESP32S3 / RP2040 based CP board...
and to optimize/shorten this is a topic of very deep-system-tweaking - maybe that is different now a days..

[bablokb]

I have a script that turns a Pi-0 into gadget mode and creates a network card: https://github.com/bablokb/raspi2go/raw/refs/heads/master/files/usr/local/sbin/raspi2go.sh. This is an old script and things tend to change within the kernel, so I am not sure it still works. The repo also has an install script that creates a suitable systemd-service to run the gadget-mode script at boot.

Regarding cold boot: you can bring down boot-times considerably with only a few tweaks. You can give this a read (run it through a translater): https://www.raspberry-pi-geek.de/ausgaben/rpg/2020/06/die-boot-zeit-von-raspbian-optimieren/. I managed to bring down boot times from 35s to 8s. It is still much longer than with a MCU, but I think 8s is ok.

I would also recommend that you turn on "read-only"-mode via raspi-config, performance options (once you are finished with your setup). With read-only mode, you can just unplug the Pi, no need to shut it down cleanly.

And as a final note: you can solder a male USB-connector to the Pi-0 (there are solder-points on the bottom side) and turn it into a pluggable stick.

[tannewt]

I think it'd be easiest to add this to the Zephyr port since it has CDC NCM support. It also has a bunch of networking integrated that we'll want to integrate for ethernet and wifi support too.

[s-light]

is there any place where we can see what status the port has?
or are there any easy tasks to support the porting?

and as i found somewhere - new boards are done first.. so could take some time for the older ones i can imagine..

[samblenny]

is there any place where we can see what status the port has?

There are several places to follow progress at different levels of detail:

• GitHub: You can follow this repository to get notifications for issues and PRs for everything, including Zephyr work. You can also navigate to the issues page and use its search feature to search for "zephyr". From issues, you can also click on the milestones button (next to New Issue) to see what work is planned for which release. You can also check release notes or look in the ports/zephyr-cp/boards folder to see which boards are included.
• CircuitPython weekly meetings: These are good for a more summarized view. Meeting recordings get posted to Adafruit's youtube. In the video description, you can find a link to the notes document. In the notes, the status updates section has bullet point lists of who's been working on what.
• CircuitPython Newsletter: If you scroll down to near the bottom of the newsletter, there's a section about what Adafruit's CircuitPython dev team are working on.

[tannewt]

is there any place where we can see what status the port has?

There isn't a great single spot. You can check: https://github.com/adafruit/circuitpython/issues?q=is%3Aissue%20state%3Aopen%20label%3Azephyr like Sam says. (Though I'm not great at always adding an issue. My branches are here too: https://github.com/tannewt/circuitpython/branches

or are there any easy tasks to support the porting?

I'd love for folks to try it and let me know what they are missing.

and as i found somewhere - new boards are done first.. so could take some time for the older ones i can imagine..

There are really two degrees of board support for the CP Zephyr port. First is that a board is supported by Zephyr. You can search their support here: https://docs.zephyrproject.org/latest/boards/index.html Once a board is, then we may enable it for CP on Zephyr so that it is automatically built and released. That's what the boards/ directory does.

You can actually build CP on Zephyr pretty easily for any Zephyr supported board and it might (hopefully) just work. I've documented how to do that here: https://github.com/adafruit/circuitpython/tree/main/ports/zephyr-cp#testing-other-boards Either you can try to build the Zephyr port for a board you have, or if you ping me on Discord, I can try for you.

[samblenny]

Learned some new stuff about OS support for USB CDC-ECM, RNDIS, and CDC-NCM...

From what I read, prior to Windows 11, to get reliable cross-platform support, you had to implement a composite device with RNDIS for Windows and CDC-ECM for everything else. This is how BeagleBone Black was traditionally set up (recent firmware may be different).

As of Windows 11, Microsoft provides a CDC-NCM driver which is recommended instead of RNDIS (see note for Rndismp.sys). Supposedly, NCM should also work on modern versions of macOS and Linux.

[s-light]

for my original project i will go with the pocket-beagle2 option!
that just makes the most sense.

for low-budget-educational context i think the CDC-NCM way is of higher interest..
and i go with the concept to wait for the Zephyr port first..

thanks for all your input! i love this community!