Notes

#!/bin/bash

# Detects if script are not running as root...
if [ "$UID" != "0" ]; then
#$0 is the script itself (or the command used to call it)...
#$* parameters...
if whereis sudo &>/dev/null; then
echo "Please type the sudo password for the user $USER"
sudo $0 $*
exit
else
echo "Sudo not found. You will need to run this script as root."
exit
fi
fi


yum install -y epel-release
yum-config-manager --add-repo https://copr.fedorainfracloud.org/coprs/macieks/openresolv/repo/epel-7/macieks-openresolv-epel-7.repo

yum update -y && yum install -y openvpn openresolv

cat > /etc/openvpn/update-resolv-conf <<DDDD
#!/usr/bin/env bash
#
# Parses DHCP options from openvpn to update resolv.conf
# To use set as 'up' and 'down' script in your openvpn *.conf:
# up /etc/openvpn/update-resolv-conf
# down /etc/openvpn/update-resolv-conf
#
# Used snippets of resolvconf script by Thomas Hood <[email protected]>
# and Chris Hanson
# Licensed under the GNU GPL. See /usr/share/common-licenses/GPL.
# 07/2013 [email protected] Fixed intet name
# 05/2006 [email protected]
#
# Example envs set from openvpn:
# foreign_option_1='dhcp-option DNS 193.43.27.132'
# foreign_option_2='dhcp-option DNS 193.43.27.133'
# foreign_option_3='dhcp-option DOMAIN be.bnc.ch'
# foreign_option_4='dhcp-option DOMAIN-SEARCH bnc.local'

## The 'type' builtins will look for file in $PATH variable, so we set the
## PATH below. You might need to directly set the path to 'resolvconf'
## manually if it still doesn't work, i.e.
## RESOLVCONF=/usr/sbin/resolvconf
export PATH=$PATH:/sbin:/usr/sbin:/bin:/usr/bin
RESOLVCONF=$(type -p resolvconf)

case $script_type in

up)
for optionname in ${!foreign_option_*} ; do
option="${!optionname}"
echo $option
part1=$(echo "$option" | cut -d " " -f 1)
if [ "$part1" == "dhcp-option" ] ; then
part2=$(echo "$option" | cut -d " " -f 2)
part3=$(echo "$option" | cut -d " " -f 3)
if [ "$part2" == "DNS" ] ; then
IF_DNS_NAMESERVERS="$IF_DNS_NAMESERVERS $part3"
fi
if [[ "$part2" == "DOMAIN" || "$part2" == "DOMAIN-SEARCH" ]] ; then
IF_DNS_SEARCH="$IF_DNS_SEARCH $part3"
fi
fi
done
R=""
if [ "$IF_DNS_SEARCH" ]; then
R="search "
for DS in $IF_DNS_SEARCH ; do
R="${R} $DS"
done
R="${R}
"
fi

for NS in $IF_DNS_NAMESERVERS ; do
R="${R}nameserver $NS
"
done
#echo -n "$R" | $RESOLVCONF -x -p -a "${dev}"
echo -n "$R" | $RESOLVCONF -x -a "${dev}.inet"
;;
down)
$RESOLVCONF -d "${dev}.inet"
;;
esac

# Workaround / [email protected]
# force exit with no errors. Due to an apparent conflict with the Network Manager
# $RESOLVCONF sometimes exits with error code 6 even though it has performed the
# action correctly and OpenVPN shuts down.
exit 0
DDDD

chmod +x /etc/openvpn/update-resolv-conf

exit 0