Re: [TLS] DTLS 1.3

[Ilari Liusvaara <[e-mail]>]

On Mon, Jul 04, 2016 at 03:54:19PM -0400, Nikos Mavrogiannopoulos wrote:
> ----- Original Message -----
> > Hi all,
> > 
> > I have made an attempt to integrate DTLS 1.3 into the TLS 1.3 document
> > and you can find the result at https://github.com/tlswg/tls13-spec/pull/512
> > 
> > I have worked on a prototype implementation of DTLS 1.3 and if someone
> > else has something working by the time of the Hackathon in Berlin please
> > let me know.
> 
> May I recommend a more radical approach for DTLS? My experience with servers
> handling DTLS traffic from various clients is that the clients change IPs (while
> roaming) and incoming ports (due to firewall state timeout), making impossible
> for the server to map the encrypted incoming packets from unknown IP/port combinations
> to any particular handler (i.e., handling process/thread or logical handler). That
> is because an independently received DTLS record packet has no session identifying
> information.

I think in DTLS 1.2, that was meant to be handled at lower layer (of course, often
there isn't such layer even when needed).
 
> For that I'd like to propose the DTLS record format to include at least a
> 3-byte identifier which will allow servers to recognize streams coming from unknown
> sources. That would be similar to the SPI field in the ESP packets. That is,
> a format similar to:

One can't change the headers in ClientHello/ServerHello and expect to remain
backwards compatible.

And how would that identifier be assigned? 0 in ClientHello, then copy whatever
the server sends?


-Ilari