heartbeat extension: doc update

Document how to calculate the total TLS data transmitted.

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

diff --git a/lib/ext/heartbeat.c b/lib/ext/heartbeat.c
index 26a0928d9ca7cf8fe0f50d9a8e81dfaa3d205542..a1b6893fae1a9b017feb8990efc4584fc2f5be33 100644 (file)
--- a/lib/ext/heartbeat.c
+++ b/lib/ext/heartbeat.c
@@ -22,8 +22,6 @@
  */
 
 /* This file implements the TLS heartbeat extension.
- * It was originally implemented during Google SoC 2012 by by Olga Smolenchuk,
- * and later rewritten by Nikos Mavrogiannopoulos.
  */
 
 #include "errors.h"
@@ -151,6 +149,9 @@ heartbeat_send_data(gnutls_session_t session, const void *data,
  * flag %GNUTLS_HEARTBEAT_WAIT, or you need to handle retransmissions
  * and timeouts manually.
  *
+ * The total TLS data transmitted as part of the ping message are given by
+ * the following formula: MAX(16, @data_size)+gnutls_record_overhead_size()+3.
+ *
  * Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
  *
  * Since: 3.1.2