Linux tun2socks routing helper

socks2vpn.sh

#!/bin/bash

if [ "$EUID" -ne 0 ]; then echo "Please run as root"; exit; fi

GATEWAY=$(ip route | awk '/default/ {print $3}')
INTERFACE=$(ip route | awk '/default/ {print $5}')
RESOLVE_CONF=$(cat /etc/resolv.conf)

SOCKS_SCHEME="socks5"
SOCKS_ADDRESS="127.0.0.1"
SOCKS_PORT="10808"

TUN_NAME="tun0"
TUN_ADDRESS="10.10.10.10"
TUN_ROUTE="default dev $TUN_NAME"
TUN_SETUP="$(realpath $0) $TUN_NAME"

PROXY_SERVER=(x.x.x.x)

EXCLUDE=(PROXY_SERVER)

addRoute() {
  local ROUTE=$(ip route | grep "$1")
  if [ -z "$ROUTE" ]; then ip route add $1; fi
}

delRoute() {
  local ROUTE=$(ip route | grep "$1")
  if [ -n "$ROUTE" ]; then ip route del $1; fi
}

excludeRoutes() {
  for name in "${EXCLUDE[@]}"; do
    declare -n list="$name"
    for ip in "${list[@]}"; do
      local ROUTE="$ip via $GATEWAY dev $INTERFACE"
      case $1 in
        "delete") delRoute "$ROUTE";;
        *) addRoute "$ROUTE";;
      esac
    done
  done
}

start() {
  # Handle Routes
  excludeRoutes

  # Handle DNS
  /opt/dns-tcp-socks-proxy/dns_proxy /opt/dns-tcp-socks-proxy/dns_proxy.conf
  
  # Start tun2socks
  tun2socks -device "tun://$TUN_NAME" -proxy "$SOCKS_SCHEME://$SOCKS_ADDRESS:$SOCKS_PORT" -tun-post-up "$TUN_SETUP" -interface "$INTERFACE" -tcp-auto-tuning
}

stop() {
  # Cleanup Routes
  excludeRoutes "delete"
  delRoute "$TUN_ROUTE"

  # Restore DNS
  echo "$RESOLVE_CONF" > /etc/resolv.conf
}

case $1 in
  "$TUN_NAME")
    ip address add "$TUN_ADDRESS/24" dev "$TUN_NAME"
    ip link set dev "$TUN_NAME" up
    addRoute "$TUN_ROUTE metric 1";;
  *)
    # Run your proxy in background
    xray run -c config.json > /dev/null &
    trap stop EXIT
    start;;
esac

DNS resolution with socks proxy in ubuntu