[OpenAFS-devel] NAT Patch and bugfix for vlserver

[Jeffrey Hutzelman]

On Wednesday, April 26, 2006 05:15:22 PM +0200 Tommie Gannert 
<d00-tga@d.kth.se> wrote:

> Hi!
>
> I've been trying to make my behind-NAT AFS-server do backups to
> a butc-server behind another NAT.
>
> That didn't work because the vlserver keeps sending the file servers'
> first address instead of the one matching the client address. vlnat
> is a patch against 1.4.0 which
>
>  1) Makes vlserver choose the best fs-address based on the number of
>     common address-bits of the RX-client.

Huh?  The modern vlserver interfaces return _all_ the addresses of a 
server, not just one.  The decision of which address to use should be up to 
the client, which is in a better position to make a decision.  It's 
possible that the backup system is still using ancient interfaces that 
refer to fileservers by a single address instead of by UUID; if so, the 
right long-term fix is to make it use the modern interfaces.

Unfortunately, this all gets very complicated when you have clients and 
servers on networks with non-globally-routable addresses, because the 
vlserver can't always know which such addresses will work for which 
clients.  I think we're going to have to come up with a general solution to 
this issue if we ever hope to support IPv6 in a reasonable way.


> Second, 1.4.1 contains a typo in vlserver.c. During command
> line processing, instead of argv[index] it says argv[i]. i is
> uninitialized. It's the "rxmaxmtu" case.

Yup, that's a bug.  You should send it to openafs-bugs.  Including a patch 
wouldn't hurt, but also shouldn't strictly be necessary in this case, since 
the fix is so obvious.

> (Isn't anyone else using "-syslog"?)

Yes; we've been using -syslog in production for quite a long time.  I bet 
not too many people use -rxmaxmtu, though, and this bug should be very 
unlikely to affect people who don't.

-- Jeffrey T. Hutzelman (N3NHS) <jhutz+@cmu.edu>
   Sr. Research Systems Programmer
   School of Computer Science - Research Computing Facility
   Carnegie Mellon University - Pittsburgh, PA