The echo server is listening on port 4242 and when it receives
UDP packet, it will reverse the data and send it back to the
caller. This can be used to verify that the IP stack is doing
something useful.
Change-Id: Ibbc48c21f2513d59480c5a3bb34c775eb3df8170
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>