+/**
+ * User registered callback for IO events (rx/tx)
+ * @param vppcom_ioevent_t* -
+ * @param void* - user passed arg to pass back
+ */
+typedef void (*vppcom_session_ioevent_cb) (vppcom_ioevent_t *, void *);
+
+/**
+ * @brief vppcom_session_register_listener accepts a bound session_index, and
+ * listens for connections.
+ *
+ * On successful connection, calls registered callback (cb) with new
+ * session_index.
+ *
+ * On error, calls registered error callback (errcb).
+ *
+ * @param session_index - bound session_index to create listener on
+ * @param cb - on new accepted session callback
+ * @param errcb - on failure callback
+ * @param flags - placeholder for future use. Must be ZERO
+ * @param q_len - max listener connection backlog
+ * @param ptr - user data
+ * @return
+ */
+extern int vppcom_session_register_ioevent_cb (uint32_t session_index,
+ vppcom_session_ioevent_cb cb,
+ uint8_t rx, void *ptr);
+