openvpnClientScripts

Some scripts to enhance the openvpn client. Especially when using tap interaces.

Using

Usage: startVpn.sh [options] <serverName>

Options

-h --help print this help
-n --not invert next option. Only works for options below
-d --default-route add default route through vpn
-t --tmux use tmux

Server Name

The name of a server configuration

Config file

You can configure some of the options in the file startVpn.conf The following options are supported:

• default-route
• tmux

To overwrite these options using the command line option use the --not option.

Why do I need sudo?

Many network operations need root privileges under most systems. Examples are creating a tap device or manually triggering dhclient.

Configuring a server

To configure a server create a folder in servers. The folder name will be used as the name for selecting the server. In this folder there needs to be the follwoing files:

• client.ovpn The openvpn client configuration
• startup.sh A script run when the connection is established. Use this to trigger dhclient and set routes.
• shutdown.sh A script run after the vpn goes down. Use this to clean up the routes.

Working directory

The working directory is changed to the folder of the server before executing openvpn, so any relative paths inside the config should be relative to it.

Startup and Shutdown scripts.

The scripts are run with root privileges and are given true or false as the first and only parameter stating whether it should create a default route.

Exmamples

startup.sh

#!/usr/bin/env bash
dhclient <tap device from config>
ip route add <some addintional network> via <some gateway> dev <tap device from config>
if [ "$1" == "true" ] ;then
vpn_ip="`host <vpn server address> | grep "has address" | sed 's/.* has address//g'`"
route_to_vpn="`ip r get $vpn_ip | grep "via" | sed 's/uid.*//g'`"
ip route add $route_to_vpn
ip route add default via <some gateway> dev <tap device from config> metric 100
fi
resolvconf -u

shutdown.sh

#Any routes containing the tap device are deleted when the device goes down.
if [ "$1" == "true" ] ;then
vpn_ip="`host <vpn server address> | grep "has address" | sed 's/.* has address//g'`"
route_to_vpn="`ip r get $vpn_ip | grep "via" | sed 's/uid.*//g'`"
ip route del $route_to_vpn
fi
resolvconf -u