Re: [btns] Q: How to deal with connection latch breaks?

["Laganier, Julien" <[e-mail]>]

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf Of
> Mike Eisler
> Sent: Thursday, July 30, 2009 3:41 AM
> To: [e-mail]
> Subject: Re: [btns] Q: How to deal with connection latch breaks?
> 
> 
> On Mon, July 27, 2009 10:01 am, Michael Richardson wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> >
> >>>>>> "Nicolas" == Nicolas Williams <[e-mail]> writes:
> >     >> My conclusion is that the API ought to provide information for
> >     >> the application about the connection latching, and it just
> does
> >     >> not seem to be there.  If you can point me to a discussion of
> >     >> this topic on the WG mail list, then I'll clear.  I'm not
> trying
> >     >> to alter consensus, but I do want to make sure that this topic
> >     >> was considered.
> >
> >     Nicolas> APIs are nice, but existing apps won't use them until
> >     Nicolas> updated, and anyways, connection latching adds value
> even
> >     Nicolas> without adding APIs, which means we need a default
> response
> >     Nicolas> to latch breaks in the absence of new APIs (either
> because
> >     Nicolas> not implemented or not used).
> >
> >   So, errno value from write(2) is not a new API.
> >   A new errno value should provide enough information, I think.
> >
> >   However, an application might know what to do with ETIMEOUT, while
> it
> > would not know what to do with EUNLATCHED or some such....
> 
> Isn't the application the entity that decided to enable latching?  If
> so,
> the application (or its author) needs to be prepared to deal with new
> error indication.
> 
> If not, what is the model for enabling latching?

The current draft says " Implementations SHOULD create IPsec channels automatically by
default when the application does not explicitly request an IPsec channel.  Implemenations MAY provide a way to disable automatic creation of connection latches." Thus the application might not know what is EUNLATCHED.

Would it be possible that the application gets ETIMEOUT, unless it has used a BTNS connction latching API of some sort, in which case it presumably knows about latching and can be returned an EUNLATCHED?

--julien