Re: Adding a new OSI layer

chrb81@xxxxxxxxx wrote:
Hi,


Not quite: you could easily add another library and then require such
applications (or their users) to LD_PRELOAD such a library. Haven't
tried that, though.
But it should work, as efence uses that to force an application to use
modified malloc/free functions. I guess that the socks package does so, too.
Maybe you'd have to use a few tricks to call the "standard" socket() and
friends but that could be solved as well. Maybe you'd really look at
socks. Haven't used that, though, too.

Ok, so you could do migration with an user space only solutions as
well.

But - given this fiftth layer would be something important and useful
and requires adding protocol headers to the transport layer headers -

It's my understanding of the concepts of IOS/OSI Layers that this cannot, should not and must not be done: each layer should be autonomous. Isn't it one of the concepts of this layering scheme that you can choose a transport layer independent of the session layer?

Besides: you cannot add to something that hasn't been created yet: when the session layer has created its PDU it will hand it to the Transport layer which will then stick its own header/trailer to it.

I guess that it should belong to the OS (kernel).

Maybe that small parts of the session layer should go into the kernel, but I don't think that the bulk of it needs to.

Again: IANANE,

Josef
--
These are my personal views and not those of Fujitsu Siemens Computers!
Josef Möllers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize
-- T. Pratchett

.

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