Re: Alternative ways to keeps ODCID on the server

[Dmitri Tikhonov <[e-mail]>]

After considering this for a few days, I now think that the "server
MAY proceed" part should be removed from the draft.  This is because
it is impossible to get ODCID from an invalid Retry token.  There is
no other way reliably to associate an incoming packet with a previous
packet (if the server were willing to stored ODCIDs in memory
somewhere).

Specifying that the server MAY proceed only makes the issue more
confusing.

  - Dmitri.

On Sat, Jan 25, 2020 at 04:36:51PM -0500, Ian Swett wrote:
> This is a bit of an edge case, so spelling out what's required to proceed
> seems reasonable to me.
> 
> On Sat, Jan 25, 2020 at 12:11 AM Christian Huitema <[e-mail]>
> wrote:
> 
> >
> > On 1/24/2020 8:41 PM, Marten Seemann wrote:
> >
> > Then it's not a *Retry* token, then it's a NEW_TOKEN token.
> > It's a kind of subtle distinction (as I noted in
> > https://github.com/quicwg/base-drafts/pull/3107#discussion_r349859380).
> >
> >
> > I understand that they are different. But look at the text in draft-25:
> >
> >    If a server receives a client Initial that can be unprotected but
> >    contains an invalid Retry token, it knows the client will not accept
> >    another Retry token.  The server can discard such a packet and allow
> >    the client to time out to detect handshake failure, but that could
> >    impose a significant latency penalty on the client.  A server MAY
> >    proceed with the connection without verifying the token, though the
> >    server MUST NOT consider the client address validated.  If a server
> >    chooses not to proceed with the handshake, it SHOULD immediately
> >    close (Section 10.3 <https://tools.ietf.org/html/draft-ietf-quic-transport-25#section-10.3>) the connection with an INVALID_TOKEN error.
> >    Note that a server has not established any state for the connection
> >    at this point and so does not enter the closing period.
> >
> > Invalid is invalid. An invalid token is something that the server cannot parse.
> > The server does not know whether the client got the token from a retry packet
> > or a new token frame, or just made it up with random bytes.
> >
> > -- Christian Huitema
> >
> >