network/tcp_fastopen: use UDP optionally

With minor changes the test can be run over UDP.
'-U' parameter should be provided to tcp_fastopen.

Changes in server:
* recv() changed to recvfrom() to get client address and port,
* server creates only one thread that manages requests from clients,
  and sends replies with sendto().
* increase default timeout, 10s -> 60s (waiting for requests).

Also rename some variables and test messages to more general form.

Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
1 file changed