[Help-gnutls] Re: TLS message boundary

[Simon Josefsson]

Ang Way Chuang <address@hidden> writes:

> Hi all,
>     Does TLS/SSL preserve data message boundary like SCTP? Is assuming 
> whatever
> message that is sent and received through gnutls_record_{send,recv} always
> respect data message boundary a correct assumption?

Hi!  No, that is an incorrect assumption.  See RFC 2246:

   The record layer fragments information blocks into TLSPlaintext
   records carrying data in chunks of 2^14 bytes or less. Client message
   boundaries are not preserved in the record layer (i.e., multiple
   client messages of the same ContentType may be coalesced into a
   single TLSPlaintext record, or a single message may be fragmented
   across several records).

You can of course use a TLV format inside the TLS channel to get what
you want.

Regards,
Simon