#!/bin/bash -e

set -x
#set -euo pipefail

GADGET_NAME="g1"
LANGUAGE="0x409" # English
CONFIGFS="/sys/kernel/config/usb_gadget/"
ID_VENDOR="0x1d6b"
ID_PRODUCT="0x0104"

SERIAL="$(grep Serial /proc/cpuinfo | sed 's/Serial\s*: 0000\(\w*\)/\1/')"
MAC="$(echo ${SERIAL} | sed 's/\(\w\w\)/:\1/g' | cut -b 2-)"
MAC_HOST="12$(echo ${MAC} | cut -b 3-)"
MAC_DEV="02$(echo ${MAC} | cut -b 3-)"

if [[ $EUID -ne 0 ]]; then
	echo "This script must be run as root"
	exit 1
fi

if [ ! -d $CONFIGFS ]; then
	modprobe libcomposite
fi

# Enter ConfigFS
cd $CONFIGFS

# Cleaning
#echo "Cleaning up existing gadget"
#echo "Stopping getty"
#systemctl stop getty@ttyGS0.service
#echo "Removing config-level functions"
find ./$GADGET_NAME/configs/*/* -maxdepth 0 -type l -exec rm {} \; || true
#echo "Removing config-level strings"
find ./$GADGET_NAME/configs/*/strings/* -maxdepth 0 -type d -exec rmdir {} \; || true
#echo "Removing config-level OS descriptors"
find ./$GADGET_NAME/os_desc/* -maxdepth 0 -type l -exec rm {} \; || true
#echo "Removing gadget-level functions"
find ./$GADGET_NAME/functions/* -maxdepth 0 -type d -exec rmdir {} \; || true
#echo "Removing gadget-level strings"
find ./$GADGET_NAME/strings/* -maxdepth 0 -type d -exec rmdir {} \; || true
#echo "Removing gadget-level configs"
find ./$GADGET_NAME/configs/* -maxdepth 0 -type d -exec rmdir {} \; || true
#echo "Removing gadget"
rmdir ./$GADGET_NAME || true
#echo "Starting getty"
#systemctl start getty@ttyGS0.service

mkdir ./$GADGET_NAME && cd ./$GADGET_NAME

# Basic info

echo $ID_VENDOR 	> idVendor  # Linux Foundation
echo $ID_PRODUCT 	> idProduct # Multifunction Composite Gadget
echo 0x0100 		> bcdDevice # v1.0.0
echo 0x0200 		> bcdUSB    # USB 2.0

#echo "Configuring gadget as composite device"
# https://msdn.microsoft.com/en-us/library/windows/hardware/ff540054(v=vs.85).aspx
echo 0xEF 		> bDeviceClass
echo 0x02 		> bDeviceSubClass
echo 0x01 		> bDeviceProtocol

#echo "Configuring OS descriptors"
# https://msdn.microsoft.com/en-us/library/hh881271.aspx
# OS descriptors
# WIndows extensions to force config
echo 1			> os_desc/use
echo 0xcd		> os_desc/b_vendor_code
echo MSFT100		> os_desc/qw_sign

mkdir -p strings/$LANGUAGE
echo "7777777" 		> strings/$LANGUAGE/serialnumber
echo "eXander"        	> strings/$LANGUAGE/manufacturer
echo "exander's Gadget"	> strings/$LANGUAGE/product

# Config #1 for OSX / Linux

mkdir -p configs/c.1/strings/$LANGUAGE
echo 250 		> configs/c.1/MaxPower
echo "Config 1"		> configs/c.1/strings/$LANGUAGE/configuration

mkdir -p functions/acm.usb0	# serial
mkdir -p functions/rndis.usb0	# network Flippin' Windows
#mkdir -p functions/ecm.usb0	# OSX / Linux
mkdir -p functions/hid.usb0	# keyboard

# https://msdn.microsoft.com/en-us/windows/hardware/gg463179.aspx
echo RNDIS		> functions/rndis.usb0/os_desc/interface.rndis/compatible_id
echo 5162001		> functions/rndis.usb0/os_desc/interface.rndis/sub_compatible_id

echo $MAC_HOST		> functions/rndis.usb0/host_addr
echo $MAC_DEV		> functions/rndis.usb0/dev_addr
#echo $MAC_HOST		> functions/ecm.usb0/host_addr
#echo $MAC_DEV		> functions/ecm.usb0/dev_addr

# Set up the rndis device only first

ln -s functions/rndis.usb0 configs/c.1

# Tell Windows to use config #2

ln -s configs/c.1 os_desc
#ln -s configs/c.1 os_desc/c.1

# Show Windows the RNDIS device with
# bDeviceClass 0x02
# bDeviceSubClass 0x02

ls /sys/class/udc/	> UDC

# Give it time to install

sleep 5

# Yank it back

echo ""			> UDC

# Setup keyboard
echo 1			> functions/hid.usb0/protocol
echo 1			> functions/hid.usb0/subclass
echo 8			> functions/hid.usb0/report_length
echo -ne \\x05\\x01\\x09\\x06\\xa1\\x01\\x05\\x07\\x19\\xe0\\x29\\xe7\\x15\\x00\\x25\\x01\\x75\\x01\\x95\\x08\\x81\\x02\\x95\\x01\\x75\\x08\\x81\\x03\\x95\\x05\\x75\\x01\\x05\\x08\\x19\\x01\\x29\\x05\\x91\\x02\\x95\\x01\\x75\\x03\\x91\\x03\\x95\\x06\\x75\\x08\\x15\\x00\\x25\\x65\\x05\\x07\\x19\\x00\\x29\\x65\\x81\\x00\\xc0 > functions/hid.usb0/report_desc

ln -s functions/acm.usb0 configs/c.1/
#ln -s functions/ecm.usb0 configs/c.1/
ln -s functions/hid.usb0 configs/c.1/

# Reset bDeviceClass to 0x00
# This is essential to make it work in Windows 10
# Basically forces it to use device information
# in the descriptors versus assuming a particular class.

echo "0x00"		> bDeviceClass

# Re-attach the gadget
udevadm settle -t 5 || :
ls /sys/class/udc/	> UDC

# BOOM!