#!/bin/bash

HOST=$1
PORT=$2

usage () {
  echo "Usage:"
  echo "  $0 host [port]"
  echo "  port defaults to 22 (ssh)"
  exit 1
}

print_not_reachable () {
  if [ "$NOT_REACHABLE" = "1" ] ; then
    echo -n .
  else
    echo -n $HOST:$PORT is not reachable
    NOT_REACHABLE=1
  fi
}

print_up_but_port_closed () {
  if [ "$PORT_CLOSED" = "1" ] ; then
    echo -n .
  else
    echo -n $HOST is up but port $PORT is closed
    PORT_CLOSED=1
  fi
}


port_is_open () {
    OUT=$(tcptraceroute -f 255 -m 255 -q 1 -w 1 $HOST $PORT 2>&1)
    if echo "$OUT" | grep 'Destination not reached' >/dev/null ; then
	print_not_reachable
	OPEN=no
    elif echo "$OUT" | grep '\[closed\]' >/dev/null ; then
	print_up_but_port_closed
	sleep 1
	OPEN=no
    else
	OPEN=yes
    fi
}

if [ -z "$HOST" ] ; then
  usage
fi
if [ -z "$PORT" ] ; then
  PORT=22
fi

port_is_open
while [ "$OPEN" = "no" ] ; do
  port_is_open
done
echo