Implement handshake wrapup

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index f17bf99..48678ff 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -1103,6 +1103,26 @@
     return( ret );
 }
 
+void mbedtls_ssl_tls13_handshake_wrapup( mbedtls_ssl_context *ssl )
+{
+
+    MBEDTLS_SSL_DEBUG_MSG( 3, ( "=> handshake wrapup" ) );
+
+    /*
+     * Free the previous session and switch in the current one
+     */
+    if( ssl->session )
+    {
+
+        mbedtls_ssl_session_free( ssl->session );
+        mbedtls_free( ssl->session );
+    }
+    ssl->session = ssl->session_negotiate;
+    ssl->session_negotiate = NULL;
+
+    MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= handshake wrapup" ) );
+}
+
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
 
 #endif /* MBEDTLS_SSL_TLS_C */