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From: Robert Watson <rwatson@FreeBSD.org>
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To: Doug Rabson <dfr@rabson.org>
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Cc: Rick Macklem <rmacklem@uoguelph.ca>, Julian Elischer <julian@elischer.org>,
	freebsd-arch@FreeBSD.org
Subject: Re: getting a callback ip address for nfsv4 client
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On Sun, 12 Apr 2009, Doug Rabson wrote:

> While the RPC code doesn't currently expose the socket or local address, I 
> don't think there would be many problems in adding a client control 
> operation to get the local address. Its not a good idea to allow access to 
> the actual socket since that will change over reconnects. In theory, the 
> local address may also change over reconnects but that seems less likely to 
> be a problem. Also, the reconnect machinery doesn't actually create the 
> connection until the first RPC so some care would be needed to account for 
> that.

This was pretty much what I had in mind: do an initial no-op, then query the 
local address from the RPC layer.  The question then is, when do you requery 
the address, and I guess an event is needed from the RPC layer so that the NFS 
layer knows to re-query and update the server's callback address (I assume 
that's allowed?).

Robert N M Watson
Computer Laboratory
University of Cambridge