veer.sh

#!/bin/bash

## This script is very hacky way to use VPN only for specific domains.
# For example: if you have a VPN subscription and want to access Pandora outside of the USA (may or may not be legal),
# you'd run it like "veer ovpn.conf www.pandora.com"
#
## How it works:
# Fetches the domain's IPs and routes their connections through a VPN gateway.
#
## Requirements:
# - working OpenVPN setup with a config file
# - dig
#
## Installation
# wget https://gist.githubusercontent.com/ervinb/d4fe7d39f7b4762c6c5c30359eaec1d2/raw/veer.sh -O ~/bin/veer && sudo chmod +x ~/bin/veer
# (tested on Fedora 25)

ovpn_config_path=$1
domain=$2

log() {
  echo -e "## $1"
}

usage() {
  log "Usage:"
  echo "veer <ovpn.conf> <www.domain.com>"
}

check_exe() {
  if (hash "$1 2>/dev/null"); then
    log "$1 is present."
  else
    log "$1 missing!"

    exit 1
  fi
}

get_domain_ips() {
  dig $1 +short
}

check_config() {
  if ! [ -e $ovpn_config_path ]; then
    log "OpenVPN config not found at $ovpn_config_path!"

    exit 1
  fi

  if (grep '^redirect-gateway' $ovpn_config_path); then
    log "Remove 'redirect-gateway' from the OpenVPN config file, as it routes *all* traffic to the VPN!"
  fi

  log "Config OK"
}


get_tun_info() {
  route | grep -e 'UH.*tun'
}

kill_openvpn() {
  pgrep -f "[o]penvpn.*$ovpn_config_path" | xargs -I PID sudo kill PID
}

start_openvpn() {
  sudo openvpn --daemon --ping-restart 0 --persist-tun --config $ovpn_config_path

  log "Waiting for the TUN device to appear"

  while true; do
    local tun_info=$(get_tun_info)

    ! [ -z "$tun_info" ] && break

    printf "."
    sleep 2
  done

  printf "\n"
}

route_domain_trough_vpn() {
  log "Fetching VPN gateway"
  local vpn_gateway=$(fetch_vpn_gateway)

  log "Fetching IPs for $domain"
  local ips=$(get_domain_ips $domain)

  # the new routes will be auto-cleaned up after the TUN device is destroyed
  for ip in $ips; do
    log "$ip ($domain) -> $vpn_gateway (VPN GW)"
    sudo route add $ip gw $vpn_gateway
  done

  log "Done"
}

fetch_vpn_gateway() {
  # doesn't work when there are multiple TUN devices [WIP]
  get_tun_info | cut -d ' ' -f1
}

#######

if [ "$#" -ne 2 ]; then
  usage

  exit 1
fi

log "Checking requirements"
check_exe "openvpn"
check_exe "dig"

log "Verifying OpenVPN config file"
check_config

log "Cleaning leftover OpenVPN instances if present"
kill_openvpn

log "Starting OpenVPN client"
start_openvpn

log "Routing domain IPs to VPN gateway"
route_domain_trough_vpn

log "Open $domain and enjoy!"