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Six
Registered: Apr 2002
Posts: 293 |
Punter File Transfer Protocol
Reading the doc here: http://cbmfiles.com/genie/geniefiles/TelcomTools/C1-PROTOCOL-DE..
it outlines what seems like a very simple protocol. Seems easy to implement from scratch. To that end, I set up two tcpser instances, two instance of VICE with CCGMS 11, and began a transfer, observing the logging output of TCPSER.
What Steve Punter describes should go like this:
SENDER
[dummy packet 1]---ACK---[filetype packet]---ACK---[First file packet]---ACK---[Second file packet]....
RECEIVER
----------------GOO---S/B-----------------GOO---S/B------------------GOO---S/B-- ------------------GOO...
Where dummy packet 1 would be just the two checksums, 8 for the "next block size", and a block number of 0000, filetype packet is much the same, but with the filetype as the payload and a larger "next block size"
But what I'm observing looks more like this:
SENDER
--------------------------------------------------0x91---ACK---[odd data block]---ACK---SYN---S/B---ACK---[data block 1]
RECEIVER
GOO(over and over again until the transfer starts)----GOO---S/B---------------GOO---S/B---SYN---GOO---S/B----
Where the odd data block has a next block size of 4, and a block number of 0xffff and appears to have the file type in it.
My next step is going to be to try multi-punter on the same setup, then try a few different terms and see if the peculiarities are specific to this implementation of punter on CCGMS 11.
Has anyone else dug into this, or have any insight into the how/why? Is there a comprehensive documentation of this protocol anywhere? |
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Burglar
Registered: Dec 2004
Posts: 1101 |
Quoting MagerValpWow that is one seriously fucked up protocol. I don't think I could come up with something slower and more error prone if I tried. faster than xmodem! at least the xmodem used by ucbbs and cbase. punter would only work if u didnt have too much delay+linenoise, horrible but the fastest available. |
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Count Zero
Registered: Jan 2003
Posts: 1932 |
also xmodem padded blocks with a crap byte at the end - argl :) - thats not even an alternative to anything! |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
Quote:faster than xmodem!
indeed =)
what i find kindof funny is that in the original punter "docs" it says that the protocol was made especially for bad connections. ugh =) |
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Six
Registered: Apr 2002
Posts: 293 |
Well, it does do two different types of checksumming, and theoretically has a shifting block size one could use to deal with regular interference. (no-one implements this, at least as far as I have seen)
Multi-punter's the real train wreck. There's not even any facility that I can see to deal with missing the filename/retrying. |
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Didi
Registered: Nov 2011
Posts: 487 |
Found this today. Said to be sourcecode of Punter Protocol.
http://www.lemon64.com/forum/viewtopic.php?t=56823 |
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Six
Registered: Apr 2002
Posts: 293 |
Aye, it's one of them. Unfortunately doesn't appear to include multi-punter, though I've got that working now as well. |
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JackAsser
Registered: Jun 2002
Posts: 2014 |
Quote: Aye, it's one of them. Unfortunately doesn't appear to include multi-punter, though I've got that working now as well.
Could you please write a spec that supports both single and multi on CodeBase for future generations? :) |
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morphfrog
Registered: Mar 2002
Posts: 33 |
As I find this very interesting project , I must ask did you had some time to continue or are it halted right now? |
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Six
Registered: Apr 2002
Posts: 293 |
It's an ongoing project, but this month my focus is on getting material together for the ECCC get-together on 2015-08-29.
Multi-punter does now work in CBMTerm, but whether or not it would work with a variety of other terminals besides the version of CCGMS it was tested against remains to be seen.
The only reasonable next step is to set up a variety of BBS and terminal software and individually test them until the most common variants of multi-punter are ferretted out and can be handled by my protocol layer. Probably going to be into September on that one. |
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Larry
Registered: Feb 2007
Posts: 26 |
Did this ever got finished ? |
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