client.down

the open vpn source code in linux

#!/bin/bash

# Copyright (c) 2005 by OpenVPN Solutions LLC
# Licensed under the GPL version 2

# First version by Jesse Adelman
# someone at boldandbusted dink com
# http://www.boldandbusted.com/

# PURPOSE: This script automatically removes the /etc/resolv.conf entries previously
# set by the companion script "client.up".

# INSTALL NOTES:
# Place this in /etc/openvpn/client.down
# Then, add the following to your /etc/openvpn/<clientconfig>.conf:
#   client
#   pull dhcp-options
#   up /etc/openvpn/client.up
#   down /etc/openvpn/client.down
# Next, "chmod a+x /etc/openvpn/client.down"

# USAGE NOTES:
# Note that this script is best served with the companion "client.up"
# script.

# Only tested on Gentoo Linux 2005.0 with OpenVPN 2.0
# It should work with any GNU/Linux with /etc/resolv.conf

# This runs with the context of the OpenVPN UID/GID 
# at the time of execution. This generally means that
# the client "up" script will run fine, but the "down" script
# will require the use of the OpenVPN "down-root" plugin
# which is in the plugins/ directory of the OpenVPN source tree

# A horrid work around, from a security perspective,
# is to run OpenVPN as root. THIS IS NOT RECOMMENDED. You have
# been WARNED.

# init variables

i=1
j=1
unset fopt
unset dns
unset opt

# Convert ENVs to an array

while fopt=foreign_option_$i; [ -n "${!fopt}" ]; do
{
	opt[i-1]=${!fopt}
	case ${opt[i-1]} in
		*DOMAIN* ) domain=`echo ${opt[i-1]} | \
				sed -e 's/dhcp-option DOMAIN //g'` ;;
		*DNS*    ) dns[j-1]=`echo ${opt[i-1]} | \
				sed -e 's/dhcp-option DNS //g'`
			       let j++ ;;
	esac
	let i++
}
done

# Now, do the work

if [ -n "${dns[*]}" ]; then
	for i in "${dns[@]}"; do
		sed -i -e "/nameserver ${i}/D" /etc/resolv.conf || die
	done
fi

if [ -n "${domain}" ]; then
	sed -i -e "/search ${domain}/D" /etc/resolv.conf || die
fi

# all done...
exit 0