From: cburnett@us.ibm.com
Date: 07/24/02-07:00:37 AM Z
From: cburnett@us.ibm.com
Subject: Re: Delegations mandatory?
Message-ID: <OF309601AB.F88AD1D3-ON85256C00.00416FA3@us.ibm.com>
Date: Wed, 24 Jul 2002 07:00:37 -0500
Interesting that you mentioned the idea of a way for a client to tell the
server "don't consider delegations for me". I was thinking about posting on
this just yesterday. It would be nice to have a way for the client to
indicate on the SETCLIENTID call that it does not want to be considered for
delegatons. That way, the server does not have to bother with the CB_NULL
call to see if the callback path works. Seems like the idea of NULLing out
the callback info is reasonable. Also if one considers Mike E's recent idea
of a seperate SETCALLBACK operation, then a client just doesn't bother
sending callback info.
Carl
Carl Burnett
AIX Kernel Architecture - Distributed File Systems
(512) 838-8498, TL 678-8498
(please reply to cburnett@us.ibm.com)
Peter Åstrand
<astrand@lysator.liu. To: nfsv4-wg@sunroof.eng.sun.com
se> cc:
Sent by: owner-nfsv4- Subject: Delegations mandatory?
wg@sunroof.eng.sun.com
07/24/2002 05:49 AM
Is it mandatory for clients to support delegations? The description of
OPEN makes it look like that:
"Note that delegation is up to the server to decide. The client
should never assume that delegation will or will not be granted in a
particular instance. It should always be prepared for either case."
Also, the description of SETCLIENTID:
"The callback information provided in this operation will be used if
the client is provided an open delegation at a future point.
Therefore, the client must correctly reflect the program and port
numbers for the callback program at the time SETCLIENTID is used."
I think it's a bit strange if the spec says that clients must implement
support for delegations. Simple clients, without delegation support, are
often useful.
In practice, one way of "preventing" delegations is to specify an
"invalid" cb_client4 in SETCLIENTID. This seems to work at least with the
CITI Linux server. The only problem is that the spec does not describe how
an "invalid" cb_client4 looks like. I think it should. We could say that
if SETCLIENTID4args.callback.cb_program == 0 and
SETCLIENTID4args.callback.cb_location.r_netid == "" and
SETCLIENTID4args.callback.cb_location.r_addr == "", then the server
promises not to grant delegations. Or something like that.
--
/Peter Åstrand <astrand@lysator.liu.se>
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