Simple OpenVPN connection manager.

openvpn_manager.sh

#!/bin/bash

# File location
OVPN_CONFIG="$HOME/local/settings/acanac.ovpn"
OVPN_USER="$HOME/local/settings/acanac.user"
OVPN_PID="/tmp/acanac.pid"
OVPN_LOG="/tmp/acanac.log"

IP_SERVICE="http://myip.dnsomatic.com"

echo "OpenVPN connection manager"

#### Ask yesno question. ####
# Usage: yesno OPTIONS QUESTION
#   Options:
#     --timeout N    Timeout if no input seen in N seconds.
#     --default ANS  Use ANS as the default answer on timeout or
#                    if an empty answer is provided.
# Exit status is the answer.
function yesno()
{
    local ans
    local ok=0
    local timeout=0
    local default
    local t
    while [[ "$1" ]]
    do
        case "$1" in
        --default)
            shift
            default=$1
            if [[ ! "$default" ]]; then error "Missing default value"; fi
            t=$(tr '[:upper:]' '[:lower:]' <<<$default)

            if [[ "$t" != 'y'  &&  "$t" != 'yes'  &&  "$t" != 'n'  &&  "$t" != 'no' ]]; then
                error "Illegal default answer: $default"
            fi
            default=$t
            shift
            ;;

        --timeout)
            shift
            timeout=$1
            if [[ ! "$timeout" ]]; then error "Missing timeout value"; fi
            if [[ ! "$timeout" =~ ^[0-9][0-9]*$ ]]; then error "Illegal timeout value: $timeout"; fi
            shift
            ;;

        -*)
            error "Unrecognized option: $1"
            ;;

        *)
            break
            ;;
        esac
    done
    if [[ $timeout -ne 0  &&  ! "$default" ]]; then
        error "Non-zero timeout requires a default answer"
    fi
    if [[ ! "$*" ]]; then error "Missing question"; fi
    while [[ $ok -eq 0 ]]
    do
        if [[ $timeout -ne 0 ]]; then
            if ! read -t $timeout -p "$*" ans; then
                ans=$default
                echo
            else
                # Turn off timeout if answer entered.
                timeout=0
                if [[ ! "$ans" ]]; then ans=$default; fi
            fi
        else
            read -p "$*" ans
            if [[ ! "$ans" ]]; then
                ans=$default
            else
                ans=$(tr '[:upper:]' '[:lower:]' <<<$ans)
            fi
        fi
        if [[ "$ans" == 'y'  ||  "$ans" == 'yes'  ||  "$ans" == 'n'  ||  "$ans" == 'no' ]]; then
            ok=1
        fi
        if [[ $ok -eq 0 ]]; then warning "Valid answers are: yes y no n"; fi
    done
    [[ "$ans" = "y" || "$ans" == "yes" ]]
}

# Get PID
VPNPID=`pgrep openvpn`

# Check if there is a openvpn process running.
if [ ! -z "$VPNPID" ]
then
    echo "There is already an instance of OpenVPN running."
    echo "PID: $VPNPID"
    if yesno --timeout 3 --default no "Stop the VPN?(yes,NO) "
    then
        # Terminate the VPN via a SIGTERM
        echo "Terminating OpenVPN process"
        sudo kill $VPNPID
    else
        # Nothing to do
        echo -e "Exiting."
    fi
    exit 0
else
    # No VPN running, shall we start one?
    echo -n "No OpenVPN instance. "
    if yesno --timeout 2 --default yes "Start the VPN?(YES/no)"
    then
        # Request Sudo privileges (so it won't break the display)
        sudo -v
        echo -n "Starting ..."
    else
        echo "Exiting."
        exit 0
    fi
fi

# Get current public IP
DIRECTIP=`curl -s $IP_SERVICE`

# Start the openvpn process
sudo openvpn --config $OVPN_CONFIG --auth-user-pass $OVPN_USER --writepid $OVPN_PID --log $OVPN_LOG &

# Add a bit of sleep otherwise the next step uses the old file.
sleep 1

# Wait for complete connection
echo -n "Initialization..."
while [ `sudo grep -c 'Initialization Sequence Completed' $OVPN_LOG` -eq 0 ]
do
    echo -en '/\b' ; sleep 0.1
    echo -en '-\b' ; sleep 0.1
    echo -en '\\\b' ; sleep 0.1
    echo -en '|\b' ; sleep 0.1
done
echo -en " Complete!\n"

# For safety, let's revoke sudo privileges
sudo -k

# Get (hopefully) new public IP
VPNIP=`curl -s $IP_SERVICE`

echo "NETWORK IP: $DIRECTIP"
echo "VPN IP:     $VPNIP"