#! /bin/bash
#
# Starts redirecting tcp connections from the internet to the local network
#

# Exits on failure
set -e

# Default paths and options
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
DAEMON="/usr/bin/redir"
DAEMON_OPTS="--lport 8888 --cport 8888 --caddr 192.168.0.170"

# Check if daemon is executable, otherwise exit script
test -x $DAEMON || exit 0

# Load standard text functions
. /lib/lsb/init-functions

# Fill in a default pid of 1 if pidfile doesn't exist yet
if [ ! -e /var/run/redir.pid ]; then
  echo "1" > /var/run/redir.pid
fi

# Custom Functions:

# simply tells the redir daemon to start, only tries starting the daemon once
# outputs "[fail]" on failure, or "[OK]" on success, no other output or action is taken
start_redir_daemon() {
	start-stop-daemon --start --quiet --pidfile /var/run/redir.pid --make-pidfile --background --exec $DAEMON -- $DAEMON_OPTS || log_end_msg 1	# "[fail]"
	log_end_msg 0	# "[OK]"
}

# tries to stop the daemon up to 5 times (with 1 second pause inbetween) before giving up
# outputs "[fail]" and a warning and then exits script on failure, otherwise outputs "[OK]" on success
stop_redir_daemon() {
	COUNTER=0
	while ( ps -p $(cat /var/run/redir.pid) | grep -q redir ); do
		let COUNTER=COUNTER+1 
		if [ "$COUNTER" -ge "5" ]; then
			log_end_msg 1		# end the previous message with "[fail]"
			log_warning_msg "Unable to stop Redir Daemon after 5 retries."
			exit 1			# exit script
		fi
		start-stop-daemon --stop --quiet --oknodo --pidfile /var/run/redir.pid
		sleep 1				# wait 1 second before checking if process was successfully killed
	done
	log_end_msg 0				# end the previous message with "[OK]" on success
}

# Main Logic:

case "$1" in
	start)
		if ( ps -p $(cat /var/run/redir.pid) | grep -q redir ); then
			log_warning_msg "Redir Daemon is already running."
		else
			log_begin_msg "Starting Redir Daemon..."
			start_redir_daemon
		fi
		;;
	stop)
		if ( ps -p $(cat /var/run/redir.pid) | grep -q redir ); then
			log_begin_msg "Stopping Redir Daemon..."
			stop_redir_daemon
		else
			log_warning_msg "Redir Daemon is already stopped."
		fi
		;;
	restart)
		log_begin_msg "Stopping Redir Daemon..."
		stop_redir_daemon
		log_begin_msg "Starting Redir Daemon..."
		start_redir_daemon
		;;
	*)
		log_success_msg "Usage: /etc/init.d/redir {start|stop|restart}"
		exit 1
esac

exit 0