[luigi@onelab2.iet.unipi.it: Re: [mef@cs.princeton.edu: Re: [Planetlab-devel] nodes with small capacities - memory footprint, xmlrpc, and requirements on encryption s/w]]

Fri May 30 08:48:38 EDT 2008

move the discussion to the list after i joined

----- Forwarded message from luigi <luigi at onelab2.iet.unipi.it> -----

Date: Fri, 30 May 2008 13:10:26 +0200
From: luigi <luigi at onelab2.iet.unipi.it>
Subject: Re: [mef at cs.princeton.edu: Re: [Planetlab-devel] nodes with small capacities - memory footprint, xmlrpc, and requirements on encryption s/w]
To: mef at cs.princeton.edu,
        Thierry Parmentelat <thierry.parmentelat at sophia.inria.fr>

marc, thierry,
Marta forwarded me these email, i realize i am not a member of
the planetlab-devel list, so can you please add me ?

On the topic - i did not want to replace sha with something else,
just to know which functionalities I should add to my tiny C code
to talk to MyPLC

SHA is one piece and i have no problem with it, i was wondering if
there is some other thing (crypto, encoding, etc.) that is used
right now.

Just for the records, the code i posted can already run queries such as
these

> ./xmlrpc $URL "GetNodes($AUTHSTRING, {dummybox_id=60}, ['node_id','hostname','slice_ids'])"
got [{slice_ids=[6],node_id=10,hostname="node2.iet.unipi.it"},{slice_ids=[7,6],node_id=13,hostname="node5.iet.unipi.it"}]

and I am planning to extend my code so one can pull selected fields
from the response. This should make it easy to manipulate the data from
C or Shell or other scripts.
It will _not_ evolve to a fully featured programming language.

	cheers
	luigi

On Fri, May 30, 2008 at 12:55:13PM +0200, Marta Carbone wrote:
> ----- Forwarded message from "Marc E. Fiuczynski" <mef at cs.princeton.edu> -----
> 
> From: "Marc E. Fiuczynski" <mef at cs.princeton.edu>
> To: PlanetLab Development <devel at planet-lab.org>
> Subject: Re: [Planetlab-devel] nodes with small capacities - memory footprint,
> 	xmlrpc, and requirements on encryption s/w
> Date: Fri, 30 May 2008 06:08:38 -0400
> Cc: 
> 
> Hey Thierry (and Luigi),
> 
> This is interesting. I too have been considering of running a little  
> node manager (i.e., component manager) on a constrained device (in  
> this case a wifi mesh node) to obtain configuration information etc.  
> from MyPLC.  There is no requirement whatsoever to use python and  
> Luigi's work is timely and definitely of interest!
> 
> To use an alternative to sha seems to require that the CM and PLCAPI  
> specify alternative schemes, rather than assuming SHA.  I agree this  
> would be a welcome change, though not that high on our prio list.   
> Can your team (or Luigi's team) do this in a way that has minimal  
> impact on the API / code base, is ideally backwards compatible, is  
> arguably similarly secure (if not just as secure), and summarize this  
> in a brief note + patch.
> 
> Marc
> 
> 
> On May 30, 2008, at 5:36 AM, Thierry Parmentelat wrote:
> 
> >Hi folks
> >
> >I am forwarding below a message from Luigi Rizzo, who wrote  
> >dummynet and who is contributing the integration into onelab.
> >
> >My own comments are that he is one of the first ones to actually  
> >deal with small-capacity nodes in real, and that he is raising a  
> >very good point; in particular this might need to be considered in  
> >the discussion about using UML, or generally more strongly typed  
> >data models, rather than raw xmlrpc; at least in the case where one  
> >of the endpoints is a node, as it can be argued that  
> >infrastructures wont have such limitations.
> >
> >The team's feelings about using variants to sha will be welcome as  
> >well.
> >
> >
> >I am attaching Luigi's code for your amusement, as he put it :)
> >
> ><xmlrpc.tgz>
> >
> >
> >Begin forwarded message:
> >
> >>From: Luigi Rizzo <rizzo at iet.unipi.it>
> >>Date: May 29, 2008 11:23:26 AM CEDT
> >>To: Thierry Parmentelat <Thierry.Parmentelat at sophia.inria.fr>,  
> >>Marta Carbone <marta at prova.iet.unipi.it>
> >>Cc: Luigi Rizzo <rizzo at iet.unipi.it>
> >>Subject: xmlrpc access to the PLC
> >>
> >>Thierry,
> >>in doing the dummynetbox we realized that using Python to access the
> >>PLC requires us to load between 15 and 30MB of stuff on the image,
> >>just because of the tangling between the various python libraries
> >>that do everything.
> >>
> >>This is disturbing because the dummynet box image has limited size,
> >>and when it grows too much we start hitting various system  
> >>limitations
> >>(memory disk size, etc.) which are hard to track.
> >>
> >>We are trying to replace the Python client code (NodeBootCall.py
> >>and NodeSessionCall.py) with some other solution, also based
> >>on XMLRPC of course, with a more limited memory footprint.
> >>
> >>This will also be useful in case we might want to add to the Onelab
> >>infrastructure some 'small' devices (e.g. shapers, routers, wireless
> >>gateways) which might need to talk to the PLC.
> >>
> >>At the moment we have developed some trivial C code which,
> >>with just 20Kbytes instead of 15MB, can run
> >>XMLRPC requests over https and parse the results.
> >>
> >>So far all fine, but we now need to know what kind of libraries we
> >>might need on the client side to perform the various processing.
> >>
> >>Right now the only obvious thing is the code used in the hmac library
> >>
> >>	hmac.new(nodeKey, msg.encode('utf-8'), sha).hexdigest()
> >>
> >>Do you foresee any change in this area e.g. using some other
> >>hashing algorithm other than sha, etc. ?
> >>
> >>	cheers
> >>	luigi
> >
> >_______________________________________________
> >Devel mailing list
> >Devel at lists.planet-lab.org
> >https://lists.planet-lab.org/mailman/listinfo/devel
> 
> 
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> 
> ----- End forwarded message -----

----- End forwarded message -----