11:24 am, 19 Nov 03
protocol hackery
When I was talking to Jeff (who I think said he was involved in reverse-engineering ICQ) about protocol stuff, he mentioned he knows the guy who wrote gnapster (for context: I wrote “gnome-napster”, Jeff’s friend wrote “gnapster”, and 
four wrote “gnap”, and they all did about the same thing and sucked a whole bunch). This friend, anyway, is supposedly now working on a multiprotocol file-“sharing” client that speaks a bunch of different protocols. From there, MLDonkey came up.
MLDonkey is this crazy awesome multiprotocol file-“sharing” client that is completely written in OCaml, which is pretty cool in itself. But Jeff was telling me: they were the first to figure out Fasttrack, the superfancy protocol spoken by Kazaa and Morpheus and (etc.), which is where all the Napster-style P2P action is these days (bittorrent is big too, but it works from a different model). The Kazaa people make their money off of ads and spyware in the client, so they don’t want other clients on their network, so they change the protocol regularly to try to keep clients off. (See also: all of the battles people went through to get AIM’s OSCAR to work.)
Here’s the punchline: Fasttrack changed in some mysterious way, and nobody could figure it out. So some (totally insane) people wrote this program that extracts the machine code from the Kazaa executable and generates code that emulates a PC well enough for the code to run. It’s reportedly some horrible 20,000 line file/function that takes in some input and gives you back some magical output that just manages to work.
(Disclaimer: the facts were likely exaggerated in this to make it sound more legendary.)
Update: found it! Hahaha, that’s so ugly slash awesome!
four wrote “gnap”, and they all did about the same thing and sucked a whole bunch). This friend, anyway, is supposedly now working on a multiprotocol file-“sharing” client that speaks a bunch of different protocols. From there, MLDonkey came up.MLDonkey is this crazy awesome multiprotocol file-“sharing” client that is completely written in OCaml, which is pretty cool in itself. But Jeff was telling me: they were the first to figure out Fasttrack, the superfancy protocol spoken by Kazaa and Morpheus and (etc.), which is where all the Napster-style P2P action is these days (bittorrent is big too, but it works from a different model). The Kazaa people make their money off of ads and spyware in the client, so they don’t want other clients on their network, so they change the protocol regularly to try to keep clients off. (See also: all of the battles people went through to get AIM’s OSCAR to work.)
Here’s the punchline: Fasttrack changed in some mysterious way, and nobody could figure it out. So some (totally insane) people wrote this program that extracts the machine code from the Kazaa executable and generates code that emulates a PC well enough for the code to run. It’s reportedly some horrible 20,000 line file/function that takes in some input and gives you back some magical output that just manages to work.
(Disclaimer: the facts were likely exaggerated in this to make it sound more legendary.)
Update: found it! Hahaha, that’s so ugly slash awesome!
A different housemate (not the one I just wrote about in your other entry) uses a program called Sharaza, which reportedly talks Gnutella2, eDonkey and BitTorrent and uses them all at once to get files faster. It's actually the main thing that was sucking all of our bandwidth in the house and made me finally set up traffic shaping the other day.
It doesn't do Fasttrack, though. I wonder why people go on using KaZaa and not just use the alternative versions which talk the old version of the protocol. People stopped using Gnutella because it didn't scale, and people stopped using Napster because they got shut down… what will it take to stop people using KaZaa and move on to a completely open, documented alternative?
1. More content on open networks.
2. True anonymity.
Amount of content is a function of amount of users.
From what I hear, the quality of content on the Fasttrack network is pretty poor anyway. My housemates seem pretty insistant that there's nothing of any quality to be had there.
True anonymity without making things really inefficient is impossible. I really hope no-one tries this, as I really don't need my housemates encouraging even more of other people's traffic to route into our LAN and out again.
They could have instead used objdump and objcopy to extract the relevant routines and then linked them in with their executable. This is quite a roundabout way of doing things.
I'm just sure if I'm impressed with their disassembly -> c converter, or disappointed that they didn't know how to use objcopy.
This is, of course, assuming that I'm right about what's going on here.
I was mostly impressed by how outrageous it was. :)