NordVPN helper for GNU/Linux

vpn.sh

#!/bin/bash

# depends on openvpn (https://openvpn.net/) and json (npm install -g json)
# WARNING: stores credentials in plain text. It would be much better not to do this...

E_FAILED_DOWNLOAD=3
E_USER_ABORT=4
E_UNZIP=5
E_NOTRUNNING=6
E_ALREADYRUNNING=7

showHelp() {
	echo "USAGE: vpn [OPTIONS | kill]" >&2
	echo "OPTIONS:" >&2
	echo " -h      Show this help." >&2
	echo " -k      Kill a running instance of openvpn (same as argument 'kill')." >&2
	echo " -t      Use TCP mode." >&2
	echo " -u      Use UDP mode (default)." >&2
}

bak() {
	local path="$1"
	local bakPath="$path.bak"
	[[ -e "$path" ]] \
		&& sudo mv "$path" "$bakPath" \
		&& echo -n "$bakPath"
}

rmBak() {
	local path="$1"
	local bakPath="$path.bak"
	[[ -e "$path" && -e "$bakPath" ]] \
		&& sudo rm -rf "$bakPath"
}

runningInstances="$(ps -e -o comm | grep openvpn)"
killVpn() {
	if [[ -n "$runningInstances" ]]; then
		sudo killall openvpn
		exit $!
	else
		echo "openvpn is not currently running." >&2
		exit $E_NOTRUNNING
	fi
}

mode=udp
while getopts hktu flag; do
	case $flag in
		h) showHelp; exit;;
		k) killVpn;;
		t) mode=tcp;;
		u) mode=udp;;
	esac
done
[[ $OPTIND -gt 1 ]] && shift $((OPTIND-1))

if [[ $1 = kill ]]; then
	killVpn
elif [[ -n "$runningInstances" ]]; then
	echo "openvpn is already running. Run '$(basename "$0") kill' to stop it." >&2
	exit $E_ALREADYRUNNING
fi

recommendedServer="$(curl -s 'https://nordvpn.com/wp-admin/admin-ajax.php?action=servers_recommendations' | json [0].hostname)"
echo "Using recommended server $recommendedServer" >&2

serverConfigDir="/etc/openvpn"
configPath="$serverConfigDir/ovpn_$mode/$recommendedServer.$mode.ovpn"

configArchiveUrl="https://downloads.nordcdn.com/configs/archives/servers/ovpn.zip"
configArchiveHost="downloads.nordcdn.com"

if [[ ! -f "$configPath" ]]; then
	if confirm-prompt "$recommendedServer is not among known vpn config files. Download new files from $configArchiveHost?"; then
		downloadArchivePath="$HOME/.vpnservers.zip"
		if wget --no-clobber -O "$downloadArchivePath" "$configArchiveUrl" || true; then
			cd "$serverConfigDir"

			bak "$serverConfigDir/ovpn_tcp"
			bak "$serverConfigDir/ovpn_udp"

			sudo unzip "$downloadArchivePath" || {
				echo "Failed to unzip server configs into $serverConfigDir"
				exit $E_UNZIP
			}

			rm "$downloadArchivePath"

			rmBak "$serverConfigDir/ovpn_tcp"
			rmBak "$serverConfigDir/ovpn_udp"
		else
			echo "Unable to download new VPN server configurations." >&2
			exit $E_FAILED_DOWNLOAD
		fi
	else
		echo "Aborting" >&2
		exit $E_USER_ABORT
	fi
fi

logPath="/var/log/openvpn.log"
if [[ ! -f "$logPath" ]]; then
	sudo touch "$logPath"
fi

echo "Using mode '$mode'." >&2

openvpnOptions=()
openvpnOptions+=(--log "$logPath")
openvpnOptions+=(--config "$configPath")
openvpnOptions+=(--daemon)

passPath="/tmp/nordvpn.auth"
if [[ ! -f "$passPath" ]] && confirm-prompt "Remember username/password?"; then
	read -p 'Enter Auth Username: ' username
	read -p 'Enter Auth Password: ' -s password
	echo -e "$username\n$password" > "$passPath"
	unset username
	unset password
	sudoUser="$(sudo whoami)"
	sudo chown "$sudoUser" "$passPath"
	sudo chmod 600 "$passPath"
fi

if [[ -f "$passPath" ]]; then
	echo "Using saved credentials in $passPath." >&2
	openvpnOptions+=(--auth-user-pass "$passPath")
fi

if sudo openvpn "${openvpnOptions[@]}"; then
	pid=$!
	echo "The VPN is now running as a daemon. Run '$(basename "$0") kill' to stop it." >&2
else
	exitCode=$?
	echo "Failed to start the VPN." >&2
	exit $exitCode
fi