[TUHS] Research Datakit notes
robpike at gmail.com
Tue Jun 28 22:45:11 AEST 2022
One of the reasons I'm not a networking expert may be relevant here. With
networks, I never found an abstraction to hang my hat on. Unlike with file
systems and files, or even Unix character devices, which provide a level of
remove from the underlying blocks and sectors and so on, the Unix
networking interface always seemed too low-level and fiddly, analogous to
making users write files by managing the blocks and sectors themselves. It
could be all sockets' fault, but when I hear networking people talk about
the protocols and stacks and routing and load shedding and ....my ears
droop. I know it's amazing engineering and all that, but why aren't we
allowed to program the I/O without all that fuss? What makes networks so
_different_? A telling detail is that the original sockets interface had
send and recv, not read and write. From day 1 in Unix land at least,
networking was special, and it remains so, but I fail to see why it needs
It just seems there has to be a better way. Sockets are just so unpleasant,
and the endless nonsense around network configuration doubly so.
Rhetorical questions. I'm not asking or wanting an answer. I'm happy to
remain a greenhorn, oblivious to the wonder.
To adapt a reference some may recognize, I just want to read 5 terabytes.
On Tue, Jun 28, 2022 at 10:36 PM Rob Pike <robpike at gmail.com> wrote:
> 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.
> On Tue, Jun 28, 2022 at 8:39 PM Derek Fawcus <
> dfawcus+lists-tuhs at 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
>> > to establish the connection before it could reject the call, unlike
>> > 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
>> 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
>> 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
>> got to the far end?
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