/* Structure defined according to the (D)TLS */
typedef struct {
     ...
     remote_peer
     local_peer
     secure_sock_key_peer_t keys
     union sock {
                 sock_upd udp; 
                 sock_tcp tcp
               }
     wolf_session
     tinydtls_session
} tlsman_session_t

/*
 * Load the TLS/DTLS stack(s) available.
 * TODO: Handling the selection of cipher suites at this point.
 */
size_t tlsman_load_stack(int **ciphers)

/*
 * Start a DTLS handshake between the peers defined by session.
 *
 * NOTE: This can be optional 
 *
 * @session The secure session to use.
 * @flags   If SECURE_SOCK_NONBLOCK is set, this function ends after sending
 *          the first handshake flight. Otherwise, blocks until the handshake
  *         is completed.
 * @return: 0 on success, otherwise error code.
*/
size_t tlsman_client_open_channel(tlsman_session_t *session, unsigned int flags)

/*
 * Starts listening for any (D)TLS record message.
 * NOTE: See tlsman_retrieve_data_app() for the Data App record.
 * @session The secure session to use.
 * @flags   If SECURE_SOCK_NONBLOCK is set (default) the function ends after
 *          sending the first handshake flight. Otherwise, blocks until the
 *          handshake is completed.
 * @return: 0 on success, otherwise error code.
*/
tlsman_server_open_channel(tlsman_session_t *session, unsigned int flags,
                           secure_sock_key_peer_t keys )

/*
 * Returns the last error occurred in the local peer (Alerts, retransmission,
*  wrong cipher suites,  etc.).
 * @return: Error code (0 if nothing)
 */
ssize_t tlsman_return_last_known_error()

/*
 * Process the @error_id and identifies if the (D)TLS session must be terminated.
 * @error_id  Error ID
 * @return 0 if error is non-fatal.
 */
ssize_t tlsman_process_error_code (site_t error_id)

/*
 * Checks if there is a (D)TLS Data Application record pending to be passed to
 * secure_sock.  
 *
 * NOTE: This can be optional 
 *
 * @returns 0 if not.
 */
size_t tlsman_is_dtls_data_app_ready( )

/*
 * Process the last (D)TLS Data Application record available.
 * @session  The secure session to use.
 * @data     Pointer where the received data should be stored.
 * @max_len  Maximum space available at  @data.
 * @secure_handler  Callback for handling the upper layer data (can be NULL)
 * @returns  Number of bytes retrieved or error code.
 */
ssize_t tlsman_retrieve_data_app(tlsman_session_t *session,
                                 void *data,
                                 size_t max_len,
                                 sec_data_handler secure_handler )

/*
 * Send upper layer data as a (D)TLS Data Application record.
 * @session  The secure session to use.
 * @data     Pointer to data to send
 * @data_size Size of  @data.
 * @returns  0 on success or error code.
 */
size_t tlsman_send_data_app(tlsman_session_t *session, const void *data,
                            size_t data_size )

/*
 * Close the (D) TLS channel established between the peers of the session.
 * This also sends a last DTLS Alert record and releases memory used for the
 * session.
 * @returns  0 on success or error code.
*/
size_t tlsman_close_channel(tlsman_session_t *session)