[torquedev] IP version-agnostic Address Representation

Ken Nielson knielson at adaptivecomputing.com
Thu Aug 11 23:21:32 MDT 2011


----- Original Message -----
> From: "Donald Neal" <dmneal at wand.net.nz>
> To: "Torque Developers mailing list" <torquedev at supercluster.org>
> Sent: Thursday, August 11, 2011 6:05:59 PM
> Subject: [torquedev] IP version-agnostic Address Representation
> There are a range of cases in Torque where an IP address is
> represented
> by a 32-bit object. This is something of a problem where the IP
> address
> may actually be 128 bits long.
> 
> I see two distinct cases here. In one the 32-bit object is being used
> as
> a key (as with AvlNode). In this case I propose initially to take the
> lower-order 32 bits of an IPv6 address and keep going as now. This is
> simple and effiicient, but would definitely give rise to collisions
> which will confuse people in future.
> 
> So the key does in future need to change. My inclination is to use a
> struct created for the purpose containing two uint64_t's. But there
> are
> definitely other ways of doing this.
> 
> In the other case, the address is not used as a key (as in struct
> pbsnode, say). That makes it viable to use either a struct containing
> the minimum fields necessary or a sockaddr*. I'm inclined towards the
> latter on the grounds that keeping down the number of struct types in
> use makes life simpler, But again there are clearly other ways of
> doing
> this.
> 
> Does anyone have a view on this? Does anyone have any other reason to
> use a package like gmp, which I don't see as needed for this purpose
> alone?
> 
> - Donald Neal
> 

The current scheme TORQUE uses to identify trusted hosts is to use the host name and IPv4 ip address. The 32-bit IP address is used as a key to store trusted addresses in an AVL tree. The convenient thing about using this scheme is that connections are verified without the need to read any data from the stream. With the 128-bit IPv6 address the AVL tree is broken. We could change the AVL-tree to take a 128 bit key and then pad the IPv4 addresses. (I am just brain-storming).

Another thought is to have the server assign a random number to each MOM and then distribute those numbers across the cluster. This would require a change in the protocol. It also requires a reading of the incoming stream to get the number.

Just some thoughts.

Ken

The




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