From 8ae4056957dbd2e70dfe6664e6155d19c901448d Mon Sep 17 00:00:00 2001
From: Ayush Singh <ayush@beagleboard.org>
Date: Thu, 11 Dec 2025 04:51:40 +0800
Subject: [PATCH] armbian-common: ship a script to aid in setting up USB gadget
 mode

this was picked from armbian/build#8382
---
 .../setup-usbgadget-network-multi.sh          | 105 ++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 files/armbian-common/usr/share/usb-gadget-mode/setup-usbgadget-network-multi.sh

diff --git a/files/armbian-common/usr/share/usb-gadget-mode/setup-usbgadget-network-multi.sh b/files/armbian-common/usr/share/usb-gadget-mode/setup-usbgadget-network-multi.sh
new file mode 100644
index 0000000..b978bef
--- /dev/null
+++ b/files/armbian-common/usr/share/usb-gadget-mode/setup-usbgadget-network-multi.sh
@@ -0,0 +1,105 @@
+#!/bin/bash
+set -euo pipefail
+
+deviceinfo_name="USB Gadget Network"
+deviceinfo_manufacturer="Armbian"
+#deviceinfo_usb_idVendor=
+#deviceinfo_usb_idProduct=
+#deviceinfo_usb_serialnumber=
+
+exit_with_error() {
+	echo "$1"
+	exit 1
+}
+
+setup_usb_network_configfs() {
+	# See: https://www.kernel.org/doc/Documentation/usb/gadget_configfs.txt
+	CONFIGFS=/sys/kernel/config/usb_gadget
+
+	if ! [ -e "$CONFIGFS" ]; then
+		exit_with_error "$CONFIGFS does not exist, skipping configfs usb gadget"
+	fi
+
+	if [ -e "$CONFIGFS/g1" ]; then
+		echo "$CONFIGFS/g1 already exists, skipping configfs usb gadget"
+		return
+	fi
+
+	# Default values for USB-related deviceinfo variables
+	usb_idVendor="${deviceinfo_usb_idVendor:-0x1D6B}"   # Linux Foundation
+	usb_idProduct="${deviceinfo_usb_idProduct:-0x0104}" # Multifunction Composite Gadget
+	usb_serialnumber="${deviceinfo_usb_serialnumber:-0123456789}"
+	usb_network_function="ncm.usb0"
+	usb_serial_function="acm.usb0"
+
+	echo "Setting up an USB gadget through configfs"
+	# Create an usb gadet configuration
+	mkdir $CONFIGFS/g1 || exit_with_error "Couldn't create $CONFIGFS/g1"
+	echo "$usb_idVendor" > "$CONFIGFS/g1/idVendor"
+	echo "$usb_idProduct" > "$CONFIGFS/g1/idProduct"
+	echo 0x0404 > "$CONFIGFS/g1/bcdDevice"
+	echo 0x0200 > "$CONFIGFS/g1/bcdUSB"
+
+	# Create english (0x409) strings
+	mkdir $CONFIGFS/g1/strings/0x409 || echo "Couldn't create $CONFIGFS/g1/strings/0x409"
+
+	# shellcheck disable=SC2154
+	echo "$deviceinfo_manufacturer" > "$CONFIGFS/g1/strings/0x409/manufacturer"
+	echo "$usb_serialnumber" > "$CONFIGFS/g1/strings/0x409/serialnumber"
+	# shellcheck disable=SC2154
+	echo "$deviceinfo_name" > "$CONFIGFS/g1/strings/0x409/product"
+
+	# Create network function.
+	mkdir $CONFIGFS/g1/functions/"$usb_network_function" ||
+		echo "Couldn't create $CONFIGFS/g1/functions/$usb_network_function"
+
+	# Create configuration instance for the gadget
+	mkdir $CONFIGFS/g1/configs/c.1 ||
+		echo "Couldn't create $CONFIGFS/g1/configs/c.1"
+	echo 250 > $CONFIGFS/g1/configs/c.1/MaxPower
+	mkdir $CONFIGFS/g1/configs/c.1/strings/0x409 ||
+		echo "Couldn't create $CONFIGFS/g1/configs/c.1/strings/0x409"
+	echo "NCM Configuration" > $CONFIGFS/g1/configs/c.1/strings/0x409/configuration ||
+		echo "Couldn't write configration name"
+
+	# Link the network instance to the configuration
+	ln -s $CONFIGFS/g1/functions/"$usb_network_function" $CONFIGFS/g1/configs/c.1 ||
+		echo "Couldn't symlink $usb_network_function"
+
+	mkdir -p $CONFIGFS/g1/functions/"$usb_serial_function" ||
+		echo "Couldn't create $CONFIGFS/g1/functions/$usb_serial_function"
+	ln -s $CONFIGFS/g1/functions/"$usb_serial_function" $CONFIGFS/g1/configs/c.1 ||
+		echo "Couldn't symlink $usb_serial_function"
+
+	# Check if there's an USB Device Controller
+	if [ ! -d /sys/class/udc ] || [ -z "$(ls /sys/class/udc 2>/dev/null)" ]; then
+		exit_with_error "No USB Device Controller available"
+	fi
+
+	# Link the gadget instance to an USB Device Controller. This activates the gadget.
+	# See also: https://github.com/postmarketOS/pmbootstrap/issues/338
+	# shellcheck disable=SC2005
+	ls /sys/class/udc | head -1 > $CONFIGFS/g1/UDC || exit_with_error "Couldn't write UDC"
+}
+
+set_usbgadget_ipaddress() {
+	local host_ip="${unudhcpd_host_ip:-172.16.42.1}"
+	local client_ip="${unudhcpd_client_ip:-172.16.42.2}"
+	echo "Starting dnsmasq with server ip $host_ip, client ip: $client_ip"
+	# Get usb interface
+	INTERFACE=""
+	ip addr replace "${host_ip}/16" dev usb0 2>/dev/null && ip link set usb0 up && INTERFACE=usb0
+	if [ -z "$INTERFACE" ]; then
+		echo "Interfaces:"
+		ip link
+		exit_with_error "Could not find an interface to run a dhcp server on"
+	fi
+
+	echo "Using interface $INTERFACE"
+	echo "Starting the DHCP daemon"
+	ip a show $INTERFACE > /var/log/unudhcpd.log
+	nohup /usr/bin/unudhcpd -i "$INTERFACE" -s "$host_ip" -c "$client_ip" >> /var/log/unudhcpd.log 2>&1 &
+	return
+}
+setup_usb_network_configfs
+set_usbgadget_ipaddress