Autossh init script (Ubuntu) for ssh tunneling

## autossh.init.sh
#! /bin/sh
# author: Clément Désiles
# date: 01/08/2016
# source: https://gist.github.com/suma/8134207
# source: http://stackoverflow.com/questions/34094792/autossh-pid-is-not-equal-to-the-one-in-pidfile-when-using-start-stop-daemon

### BEGIN INIT INFO
# Provides:          autossh
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: autossh initscript
# Description:       establish a tunnelled connexion for remote access
### END INIT INFO

. /etc/environment
. /lib/init/vars.sh
. /lib/lsb/init-functions

TUNNEL_HOST=iam.perdu.com
TUNNEL_USER=toto
TUNNEL_PORT=42000
MONITOR_PORT=42001
KEY_PATH=/home/toto/.ssh/id_rsa

NAME=autossh
DAEMON=/usr/lib/autossh/autossh
AUTOSSH_ARGS="-M $MONITOR_PORT -f"
SSH_ARGS="-nNTv -o ServerAliveInterval=60 -o ServerAliveCountMax=3 -o IdentitiesOnly=yes -o StrictHostKeyChecking=no \
         -i $KEY_PATH -R $TUNNEL_PORT:localhost:22 $TUNNEL_USER@$TUNNEL_HOST"

DESC="autossh for reverse ssh"
SCRIPTNAME=/etc/init.d/$NAME
DAEMON_ARGS=" $AUTOSSH_ARGS $SSH_ARGS"

# Export PID for autossh
AUTOSSH_PIDFILE=/var/run/$NAME.pid
export AUTOSSH_PIDFILE

do_start() {
	start-stop-daemon --start --background --name $NAME --exec $DAEMON --test > /dev/null || return 1
	start-stop-daemon --start --background --name $NAME --exec $DAEMON -- $DAEMON_ARGS    || return 2
}

do_stop() {
	start-stop-daemon --stop --name $NAME --retry=TERM/5/KILL/9 --pidfile $AUTOSSH_PIDFILE --remove-pidfile
	RETVAL="$?"
	[ "$RETVAL" = 2 ] && return 2
	start-stop-daemon --stop --oknodo --retry=0/5/KILL/9 --exec $DAEMON
	[ "$?" = 2 ] && return 2
	return "$RETVAL"
}

case "$1" in
  start)
	log_daemon_msg "Starting $DESC" "$NAME"
	do_start
	case "$?" in
		0|1) log_end_msg 0 ;;
		2) log_end_msg 1 ;;
	esac
	;;
  stop)
	log_daemon_msg "Stopping $DESC" "$NAME"
	do_stop
	case "$?" in
		0|1) log_end_msg 0 ;;
		2) log_end_msg 1 ;;
	esac
	;;
  status)
	status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
	;;
  *)
	echo "Usage: $SCRIPTNAME {start|stop|status|restart}" >&2
	exit 3
	;;
esac