android-wifi-ipv6-tethering.sh

#!/bin/bash

# Detect tethering interface name on the phone (rndis0 or usb0)

intf_cmd=$(adb shell "su -c 'if [ -e \"/sys/class/net/usb0\" ]; then echo \"Tethering interface: usb0\"; elif [ -e \"/sys/class/net/rndis0\" ]; then echo \"Tethering interface: rndis0\"; else echo "Unable to find tethering interface."; fi'")

if [ "$intf_cmd" == "Tethering interface: usb0" ]
then
   echo "$intf_cmd"
   intf="usb0"
elif [ "$intf_cmd" == "Tethering interface: rndis0" ]
then
    echo "$intf_cmd"
    intf="rndis0"
else
    echo "$intf_cmd"
    exit 1
fi

echo "NOTE: Make sure only ONE device is connected and USB debugging and USB tethering are enabled."
read -n 1 -r -s -p $'Press enter to continue...\n'

# Obtain prefix and link-local IPv6 address of the usb tethering interface

a=$(adb shell su -c ip -6 addr | grep inet6 | awk -F '[ \t]+|/' '{print $3}' | grep -v ^::1 | grep -v ^fe80 | head -n 1 | cut -d: -f4)
b=$(echo $(adb shell su -c ip -6 addr | grep inet6 | awk -F '[ \t]+|/' '{print $3}' | grep -v ^::1 | grep -v ^fe80 | head -n 1) | grep -o .*$a)"::"
c=$b"aaaa"
d=$(adb shell su -c ifconfig $intf | grep inet6 | awk -F '[ \t]+|/' '{print $4}')
e=$(ifconfig | grep enx | awk '{print $1}' | sed -e 's/://g')

echo "Prefix: $b"
echo "Using IP: $c"
echo "Link-local address of tethering interface: $d"

# Add the IP and gateway to PC

sudo ip -6 a add $c/128 dev $e
sudo ip -6 r add default via $d dev $e

# Enable IPv6 forwarding and Proxy NDP

adb shell "su -c 'echo 1 > /proc/sys/net/ipv6/conf/all/forwarding'"
adb shell "su -c 'echo 1 > /proc/sys/net/ipv6/conf/all/proxy_ndp'"

# Add the IP on the phone

adb shell "su -c ip neigh add proxy $c dev wlan0"
adb shell "su -c ip -6 r add $c/128 dev $intf table wlan0"
adb shell "su -c ip -6 r add $c/128 dev $intf table local_network"

echo 'Done! Now you have IPv6 connectivity. You can test it with "ping ipv6.google.com".'