starcraft drop, an interal look

[thetempest]

Hi,

Does anyone know how starcraft drops someone if it knows another person in a mplayer game is hacking?? (Ie: changed minerals)?


My guess is that because each player keeps a players number of minerals at all times that it does reality checks.  Ie,  a player had 50mins one sec ago and now has 5000000..drop.

My question is, how this drop, occours.  does a client send an athoritative message to another client telling them to drop? or does the machine that hacks starcraft do internal detection wether or not it hacked?

one other question, when SC sends a players mineral values accross the net, does anyone know an info on this packet?  as to it's ID or format?

Thanks

[Adron]

A magic number is sent containing a representation of the entire state. I don't know exactly how the disconnection works, but I think that whoever discovers a magic number mismatch will stop sending/receiving packets from the player.

Since Starcraft runs synchronously, all players without the hack applied will discover the magic number mismatch at the same time and simultaneously drop the offender.

If there are two people in the game with the same hack, they'll drop everyone else but not each other and the game will split in two.

[Kp]

It's been a long time, but my recollection is you actually could change your minerals without desyncing, subject to one constraint.  You can't use the phantom minerals.  When you start a unit building, everyone checks your funds and starts the build if they think you can afford it.  So, set your minerals as high as you like -- as long as you don't purchase anything you can't actually afford, everyone will continue to honor your purchases and you'll stay synchronized.  Of course, the value of unusable phantom minerals is negligible, but that's a different issue.

[Banana fanna fo fanna]

Have you analyzed the protocol at all? I worked on it for a couple days - figured out the basic protocol somewhat - want to compare notes?

[Kp]

Have you analyzed the protocol at all? I worked on it for a couple days - figured out the basic protocol somewhat - want to compare notes?

Yes; no.

[thetempest]

yes,

storm i would love to compare notes.  PM me with some contact info, either Email or MSN or AIM or IRC or someting....

[iago]

It's been a long time, but my recollection is you actually could change your minerals without desyncing, subject to one constraint.  You can't use the phantom minerals.  When you start a unit building, everyone checks your funds and starts the build if they think you can afford it.  So, set your minerals as high as you like -- as long as you don't purchase anything you can't actually afford, everyone will continue to honor your purchases and you'll stay synchronized.  Of course, the value of unusable phantom minerals is negligible, but that's a different issue.

That's correct, kp.

Adron is also right, though, there is some number representing state, but minerals aren't part of it.