28 Jun
2022
28 Jun
'22
2:36 p.m.
I am not a networking expert. I said that already. The issue could well be
a property more of sockets than TCP/IP itself, but having the switch do
some of the call validation and even maybe authentication (I'm not sure...)
sounds like it takes load off the host.
-rob
On Tue, Jun 28, 2022 at 8:39 PM Derek Fawcus <
dfawcus+lists-tuhs(a)employees.org> wrote:
On Sun, Jun 26, 2022 at 09:57:17AM +1000, Rob Pike
wrote:
One of the things we liked about Datakit was that
the computer didn't
have
to establish the connection before it could
reject the call, unlike
TCP/IP
where all validation happens after the connection
is made.
Nor does TCP, one can send a RST to a SYN, and reject the call before it is
established. That would then look to the caller just like a non listening
endpoint, unless one added data with the RST.
So this is really just a consequence of the sockets API, and the current
implementations.
I've a vague recall of folks suggesting ways to expose that facility via
the sockets
layer, possibly using setsockopt(), but don't know if anyone ever did it.
As I recall that TCP capability was actually exposed via the TLI/XTI API,
and (for some STREAMS based TCP stacks) it did function. Although I may be
thinking of embedded STREAMS TCP stacks, not unix based stacks.
Or by 'connection' are you referring to an end-to-end packet delivery,
and that Datakit allowed a closer switch to reject a call before the packet
got to the far end?
DF