#!/bin/bash -e
# Note: must be bash; uses bash-specific tricks
#
# ******************************************************************************************************************
# This Tunnelblick script does everything! It handles TUN and TAP interfaces, 
# pushed configurations and DHCP leases. :)
# 
# This is the "Down" version of the script, executed after the connection is 
# closed.
#
# Created by: Nick Williams (using original code and parts of old Tblk scripts)
# 
# ******************************************************************************************************************

trap "" TSTP
trap "" HUP
trap "" INT
export PATH="/bin:/sbin:/usr/sbin:/usr/bin"

readonly LOG_MESSAGE_COMMAND=$(basename "${0}")

# Quick check - is the configuration there?
if ! scutil -w State:/Network/OpenVPN &>/dev/null -t 1 ; then
	# Configuration isn't there, so we forget it
	echo "$(date '+%a %b %e %T %Y') *Tunnelblick $LOG_MESSAGE_COMMAND: WARNING: No existing OpenVPN DNS configuration found; not tearing down anything; exiting."
	exit 0
fi

# NOTE: This script does not use any arguments passed to it by OpenVPN, so it doesn't shift Tunnelblick options out of the argument list

# Get info saved by the up script
TUNNELBLICK_CONFIG="$(/usr/sbin/scutil <<-EOF
	open
	show State:/Network/OpenVPN
	quit
EOF)"

ARG_MONITOR_NETWORK_CONFIGURATION="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*MonitorNetwork :' | sed -e 's/^.*: //g')"
LEASEWATCHER_PLIST_PATH="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*LeaseWatcherPlistPath :' | sed -e 's/^.*: //g')"
PSID="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*Service :' | sed -e 's/^.*: //g')"
SCRIPT_LOG_FILE="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*ScriptLogFile :' | sed -e 's/^.*: //g')"
# Don't need: ARG_RESTORE_ON_DNS_RESET="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*RestoreOnDNSReset :' | sed -e 's/^.*: //g')"
# Don't need: ARG_RESTORE_ON_WINS_RESET="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*RestoreOnWINSReset :' | sed -e 's/^.*: //g')"
# Don't need: PROCESS="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*PID :' | sed -e 's/^.*: //g')"
# Don't need: ARG_IGNORE_OPTION_FLAGS="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*IgnoreOptionFlags :' | sed -e 's/^.*: //g')"
ARG_TAP="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*IsTapInterface :' | sed -e 's/^.*: //g')"
bRouteGatewayIsDhcp="$(echo "${TUNNELBLICK_CONFIG}" | grep -i '^[[:space:]]*RouteGatewayIsDhcp :' | sed -e 's/^.*: //g')"

# @param String message - The message to log
logMessage()
{
	echo "$(date '+%a %b %e %T %Y') *Tunnelblick $LOG_MESSAGE_COMMAND: "${@} >> "${SCRIPT_LOG_FILE}"
}

trim()
{
	echo ${@}
}

if ${ARG_TAP} ; then
	if [ "$bRouteGatewayIsDhcp" == "true" ]; then
		if [ -z "$dev" ]; then
			logMessage "Cannot configure TAP interface for DHCP without \$dev being defined. Device may not have disconnected properly."
		else
			set +e
			ipconfig set "$dev" NONE 2>/dev/null
			set -e
		fi
	fi
fi

# Issue warning if the primary service ID has changed
PSID_CURRENT="$( (scutil | grep Service | sed -e 's/.*Service : //')<<- EOF
	open
	show State:/Network/OpenVPN
	quit
EOF)"
if [ "${PSID}" != "${PSID_CURRENT}" ] ; then
	logMessage "Ignoring change of Network Primary Service from ${PSID} to ${PSID_CURRENT}"
fi

# Remove leasewatcher
if ${ARG_MONITOR_NETWORK_CONFIGURATION} ; then
	launchctl unload "${LEASEWATCHER_PLIST_PATH}"
	logMessage "Cancelled monitoring of system configuration changes"
fi

# Restore configurations
DNS_OLD="$(/usr/sbin/scutil <<-EOF
	open
	show State:/Network/OpenVPN/OldDNS
	quit
EOF)"
WINS_OLD="$(/usr/sbin/scutil <<-EOF
	open
	show State:/Network/OpenVPN/OldSMB
	quit
EOF)"
TB_NO_SUCH_KEY="<dictionary> {
  TunnelblickNoSuchKey : true
}"

if [ "${DNS_OLD}" = "${TB_NO_SUCH_KEY}" ] ; then
	scutil <<- EOF
		open
		remove State:/Network/Service/${PSID}/DNS
		quit
EOF
else
	scutil <<- EOF
		open
		get State:/Network/OpenVPN/OldDNS
		set State:/Network/Service/${PSID}/DNS
		quit
EOF
fi

if [ "${WINS_OLD}" = "${TB_NO_SUCH_KEY}" ] ; then
	scutil <<- EOF
		open
		remove State:/Network/Service/${PSID}/SMB
		quit
EOF
else
	scutil <<- EOF
		open
		get State:/Network/OpenVPN/OldSMB
		set State:/Network/Service/${PSID}/SMB
		quit
EOF
fi

logMessage "Restored the DNS and WINS configurations"

# Remove our system configuration data
scutil <<- EOF
	open
	remove State:/Network/OpenVPN/SMB
	remove State:/Network/OpenVPN/DNS
	remove State:/Network/OpenVPN/OldSMB
	remove State:/Network/OpenVPN/OldDNS
	remove State:/Network/OpenVPN
	quit
EOF

exit 0