Correct record header size in case of TLS
The previous commit reduced the internal header size to 5 bytes in case of
TLS. This is not a valid since in that situation Mbed TLS internally uses the
first 8 bytes of the message buffer for the implicit record sequence number.
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index 2d99d40..c153442 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -154,14 +154,10 @@
#error Bad configuration - protected record payload too large.
#endif
-#if !defined(MBEDTLS_SSL_PROTO_DTLS)
-/* https://tools.ietf.org/html/rfc5246#section-6.2 */
-#define MBEDTLS_SSL_HEADER_LEN 5
-#else
-/* https://tools.ietf.org/html/rfc6347#section-4.1 */
-/* 8 additional bytes for epoch and sequence number */
+/* Note: Even though the TLS record header is only 5 bytes
+ long, we're internally using 8 bytes to store the
+ implicit sequence number. */
#define MBEDTLS_SSL_HEADER_LEN 13
-#endif
#define MBEDTLS_SSL_BUFFER_LEN \
( ( MBEDTLS_SSL_HEADER_LEN ) + ( MBEDTLS_SSL_PAYLOAD_LEN ) )