Steam Deck USB Ethernet

usb-ether.sh

#!/bin/sh

if [ "$UID" -ne 0 ]; then
	echo "This script needs to be executed as root"
	exit 1
fi

vendor_id="0x3000" # Valve
product_id="0x28DE"
serial_number="$(dmidecode -s system-serial-number)" # The Steam Deck's serial number
manufacturer="Valve" # Manufacturer
product="Steam Deck" # Product
device="0x1004" # Device version
usb_version="0x0200" # USB 2.0
device_class="2" # Communications
cfg1="CDC" # Config 1 description
cfg2="RNDIS" # Config 2 description
power=250 # Max power
dev_mac1="42:61:64:55:53:42"
host_mac1="48:6f:73:74:50:43"
dev_mac2="42:61:64:55:53:44"
host_mac2="48:6f:73:74:50:45"
ms_vendor_code="0xcd" # Microsoft
ms_qw_sign="MSFT100" # Microsoft
ms_compat_id="RNDIS" # Matches Windows RNDIS drivers
ms_subcompat_id="5162001" # Matches Windows RNDIS 6.0 driver

cdc_mode="ecm" # Which CDC gadget to use
start_rndis=true # Whether to start the Microsoft RNDIS gadget

while getopts "ncerR" option ${@:2}; do
	case "${option}" in
		"n")
			cdc_mode=ncm
			;;
		"c")
			cdc_mode=ecm
			;;
		"e")
			cdc_mode=eem
			;;
		"r")
			start_rndis=true
			;;
		"R")
			start_rndis=false
			;;
	esac
done

case "$1" in
	start)
		# Create the networkd config file for the USB interface
		cat << EOF > /etc/systemd/network/usb0.network
[Match]
Name=usb0

[Network]
Address=192.168.100.1/24
DHCPServer=true
IPMasquerade=ipv4

[DHCPServer]
PoolOffset=100
PoolSize=20
EmitDNS=yes
DNS=8.8.8.8
EOF

		cat << EOF > /etc/systemd/network/usb1.network
[Match]
Name=usb1

[Network]
Address=192.168.101.1/24
DHCPServer=true
IPMasquerade=ipv4

[DHCPServer]
PoolOffset=100
PoolSize=20
EmitDNS=yes
DNS=8.8.8.8
EOF

		# Start networkd
		systemctl start systemd-networkd
		
		# Enable DRD driver
		echo -n "0000:04:00.3" > /sys/bus/pci/drivers/xhci_hcd/unbind
		echo -n "0000:04:00.3" > /sys/bus/pci/drivers/dwc3-pci/bind

		# Load the drivers
		modprobe libcomposite

		# Create the gadget
		mkdir /sys/kernel/config/usb_gadget/g.1
		cd /sys/kernel/config/usb_gadget/g.1

		# Specify the vendor and product ID
		echo "${vendor_id}" > idVendor
		echo "${product_id}" > idProduct

		# Create the gadget configuration
		mkdir configs/c.1

		# Create the strings directories
		mkdir strings/0x409
		mkdir configs/c.1/strings/0x409

		# Specify the serial number, manufacturer, and product strings
		echo "${serial_number}" > strings/0x409/serialnumber
		echo "${manufacturer}" > strings/0x409/manufacturer
		echo "${product}" > strings/0x409/product

		# Specify the device version, USB specification, and device class
		echo "${device}" > bcdDevice
		echo "${usb_version}" > bcdUSB
		echo "${device_class}" > bDeviceClass

		# Set the configuration description and power
		echo "${cfg1}" > configs/c.1/strings/0x409/configuration
		echo "${power}" > configs/c.1/MaxPower

		# Create the gadget function
		mkdir functions/${cdc_mode}.0

		# Set the MAC addresses of the gadget
		echo "${host_mac1}" > functions/${cdc_mode}.0/host_addr
		echo "${dev_mac1}" > functions/${cdc_mode}.0/dev_addr

		# Start RNDIS if enabled
		if [ "${start_rndis}" = true ]; then
			# Create the gadget configuration
			mkdir configs/c.2

			# Create the strings directories
			mkdir configs/c.2/strings/0x409

			# Specify the configuration description and power
			echo "${cfg2}" > configs/c.2/strings/0x409/configuration
			echo "${power}" > configs/c.2/MaxPower

			# Set some Microsoft specific configuration
			echo "1" > os_desc/use
			echo "${ms_vendor_code}" > os_desc/b_vendor_code
			echo "${ms_qw_sign}" > os_desc/qw_sign

			# Create the gadget function
			mkdir functions/rndis.0

			# Set the MAC addresses of the gadget
			echo "${host_mac2}" > functions/rndis.0/host_addr
			echo "${dev_mac2}" > functions/rndis.0/dev_addr

			# Set the RNDIS driver version
			echo "${ms_compat_id}" > functions/rndis.0/os_desc/interface.rndis/compatible_id
			echo "${ms_subcompat_id}" > functions/rndis.0/os_desc/interface.rndis/sub_compatible_id
		fi

		# Associate the CDC function with its configuration
		ln -s functions/${cdc_mode}.0 configs/c.1/

		# Associate the RNDIS function with its configuration
		if [ "${start_rndis}" = true ]; then
			ln -s functions/rndis.0 configs/c.2
			ln -s configs/c.2 os_desc
		fi

		# Enable the gadget
		ls /sys/class/udc > UDC
		;;

	stop)
		# Disable the gadget
		cd /sys/kernel/config/usb_gadget/g.1
		echo "" > UDC

		# Remove functions from the configuration
		rm configs/c.1/ncm.0 2> /dev/null
		rm configs/c.1/ecm.0 2> /dev/null
		rm configs/c.1/eem.0 2> /dev/null
		rm configs/c.2/rndis.0 2> /dev/null

		# Remove the strings directories in configurations
		rmdir configs/c.1/strings/0x409
		rmdir configs/c.2/strings/0x409 2> /dev/null

		# Remove the configurations
		rmdir configs/c.1
		rm os_desc/c.2 2> /dev/null
		rmdir configs/c.2 2> /dev/null

		# Remove the functions
		rmdir functions/ncm.0 2> /dev/null
		rmdir functions/ecm.0 2> /dev/null
		rmdir functions/eem.0 2> /dev/null
		rmdir functions/rndis.0 2> /dev/null

		# Remove the strings directories in the gadget
		rmdir strings/0x409

		# Delete the gadget
		cd ..
		rmdir g.1

		# Unload the drivers
		cd ../../
		modprobe -r usb_f_ncm
		modprobe -r usb_f_ecm
		modprobe -r usb_f_eem
		modprobe -r usb_f_rndis
		modprobe -r libcomposite
		
		
		# Disable DRD driver
		echo -n "0000:04:00.3" > /sys/bus/pci/drivers/dwc3-pci/unbind
		echo -n "0000:04:00.3" > /sys/bus/pci/drivers/xhci_hcd/bind

		# Stop networkd
		systemctl stop systemd-networkd 2> /dev/null

		# Remove the networkd config files for USB interfaces
		rm /etc/systemd/network/usb0.network
		rm /etc/systemd/network/usb1.network
		;;
	*)
		echo "Usage:"
		echo -e "\t./usb-ether.sh start\tStarts the USB ethernet"
		echo -e "\t\t-n\tUse the CDC-NCM USB Ethernet driver (for OSX and iOS)"
		echo -e "\t\t-c\tUse the CDC-ECM USB Ethernet driver (default)"
		echo -e "\t\t-e\tUse the CDC-EEM USB Ethernet driver"
		echo -e "\t\t-r\tEnable the RNDIS USB Ethernet driver for Windows (default)"
		echo -e "\t\t-R\tDisable the RNDIS USB Ethernet driver for Windows"
		echo -e "\t./usb-ether.sh stop - Stops the USB ethernet"
		;;
esac

I think we need to freeze steam os version it worked.

What do you mean? How would we freeze the steam os version?

I can't help but to feel that Valve put a hard lockdown on sys in the recent update, or something. I thought I'd at least let you know, just in case the latest update did actually end up killing the script.

It's very likely that an update did end up killing the script, but it's not Valve putting a hard lockdown on anything. This happens every now and again because they aren't currently focused on USB DRD and the drivers sometimes stop working until they fix it. It's just a matter of time until it starts working again. It might even work on the beta right now, or stable if you're on beta. It's also possible that the script needs updating.

There's no indication that the script was functioning

I never added any, this script was mostly a proof of concept.

with the latest update, I'm unsure if there's anything that can be done about it now.

Like I said, it's only a matter of time until it works again, or the script might need updating. I will, however, not be updating this script, it's provided as-is and is and always was just a proof of concept. I'm working on instead adding this feature to my decky plugin, DeckMTP, with the next version, and slowly adding more USB gadgets and features with time.

Ah, I thought the plugin was cancelled since I first saw it mentioned years ago. Is it something you're actively working on, or are you waiting on something else before you can work on it?

The main thing I'd like is to remove the latency in Steam Link between the deck and my PC, since my router is on the other side of the house from where my computer is. And throughout what I've searched, it seemed like this script was the only thing I could find that could do it. Would the plugin be able to do this? And would it be anything I could use within the next year or two?

No, the plugin was never canceled, some things had to be rewritten first to allow this to happen. I'm still working on it, however this is unpaid work that I'm working on in my free time whenever I'm able to and I'm not burnt out from actual work.

Would the plugin be able to do this?

Both the plugin, and this script if you manage to get it to run, should be able to do this. I've seen people use this script for this exact reason.

And would it be anything I could use within the next year or two?

It's the very next thing on my list of priorities. A couple of months will do it most likely.