Can you create a guide to configure OTG ethernet mode

[zeb]

Hi,

I'd like to use the USB-port as a linux OTG gadget under debian - can you create a guide and provide necessary files similar to ADB? I can see the drivers being loaded from usbcore during boot but there is no module to load with modprobe that sticks.

The idea is to connect the USB-C to windows laptop and use ethernet over the cable (RNDIS / g_ether for raspberry pi) so that the NanoPi Zero2 becomes a VPN device



Thanks

[zeb]

For anyones interested I did this myself - after too much digging into linux configfs it led me to the /usr/bin/usbdevice (and -wrapper file).

Below should be enough to get the NanoPi Zero2 working as an OTG RNDIS ethernet adapter over the USB-C port, I ended up creating these files to get everything up and running from bootup:

/etc/usbdevice.d/usbrndis.sh (with +x permission)

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#!/bin/sh
#
# Place this file into directory (create if not existing) /etc/usbdevice.d/
#
USB_FUNCS='rndis'

/lib/systemd/system/usbrndis.service
followed by: systemctl enable usbrndis

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# Service file for USB RNDIS
#
# - place this file into /lib/systemd/system
# - run: systemctl enable usbrndis
#

[Unit]
Description=Manage USB RNDIS systemd environment
DefaultDependencies=no
Before=network.target

[Service]
Type=simple
ExecStart=/usr/bin/usbdevice start
ExecStop=/usr/bin/usbdevice stop
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

Restart system and check dmesg for usb0 messages, should see random macs assigned:
dmesg | grep usb0

Finally to add (if not using nmcli) IP addresses
/etc/network/interfaces.d/usb0.conf

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allow-hotplug usb0
iface usb0 inet static
        address 192.168.30.1/24

If using Network Manager/nmcli there is a restriction that has to be lifted to make usb0 permanently managed, place
/usr/lib/udev/rules.d/85-nm-unmanaged.rules
into
/etc/udev/rules.d/
and replace the line

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ENV{DEVTYPE}=="gadget", ENV{NM_UNMANAGED}="1"

with

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ENV{DEVTYPE}=="gadget", ENV{NM_UNMANAGED}="0"

and then nmcli dev set usb0 managed yes

That's it