Improve documentation of nonce-generating function in ssl_msg.c
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 65eab4b..32bbc97 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -557,8 +557,14 @@
* a) Fixed and dynamic IV lengths add up to total IV length, giving
* IV = fixed_iv || dynamic_iv
*
+ * This variant is used in TLS 1.2 when used with GCM or CCM.
+ *
* b) Fixed IV lengths matches total IV length, giving
* IV = fixed_iv XOR ( 0 || dynamic_iv )
+ *
+ * This variant occurs in TLS 1.3 and for TLS 1.2 when using ChaChaPoly.
+ *
+ * See also the documentation of mbedtls_ssl_transform.
*/
static void ssl_build_record_nonce( unsigned char *dst_iv,
size_t dst_iv_len,