A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back online

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ioncannon
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Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#91 » Mon Sep 19, 2022 2:41 pm

pcwzrd13 wrote:
dude2207 wrote:Oh, also created a web portal and PERL script for generating the VMS/VMI of NET files for people when the time comes. You will need to manually find your dreamcast's unique flash ID to create your NET file.


How was this done back in the day? I would assume the game would have done all this for you.


Without a NET file you'd register in the game. Then the game dials to KDDI's network and does.... something. Finally it dials to your ISP and connects to the server over PPP; sending a special character to signify a new account.

The issue is that first dial, as it's trying to PPP into their network. Normal servers don't work (tried on DreamPi and a PortMaster3) but I found out it DID work on a WinXP machine doing a share connection server.

Didn't do a deep dive but it's prob using Microsoft encryption the other stuff doesn't support. Most of the PPP packets looked the same. It just connects and then immediately disconnects but is satisfied with the result. After connecting you'd have a NET file.

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pcwzrd13
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Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#92 » Mon Sep 19, 2022 2:56 pm

@ioncannon Ah ok, gotcha.

Can you edit the NET file manually? I found what looks like an ID in hex but it's 14 characters long and my console ID is 12 characters.
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dude2207
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Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#93 » Mon Sep 19, 2022 3:35 pm

pcwzrd13 wrote:@ioncannon Ah ok, gotcha.

Can you edit the NET file manually? I found what looks like an ID in hex but it's 14 characters long and my console ID is 12 characters.

Yes we mapped out the NET file back at the end of June.

ioncannon
Anarki
Posts: 90

Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#94 » Mon Sep 19, 2022 7:25 pm

On the lobby engine front, not getting hopes up; but I was able to backtrace from the confirmed `avetcp_send` function for the Access TCP lib in the NetSDK, to the confirmed "send gate server" function.

Using the reference graph I found it was 2-3 funcs distance between each other.

Tried then with `avetcp_receive` and found matching functions.... and 2-3 funcs away was this:

Image

BIGSWITCH was a function I found earlier that looked like a giant opcode switch. Seems I was right! Time to confirm if those params sent in (they are in the heap, not static memory) contain the receive buffer!

If this is a opcode switch for the entire game then basically we cracked this thing open like the KDDI server was.

This is BIGSWITCH; like I said a giant opcode switch (or as Ghidra disassembles it, if statement list):

Image

ioncannon
Anarki
Posts: 90

Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#95 » Mon Sep 19, 2022 7:48 pm

Alright, found the receive buffer using that nice Flycast Debugger, and it's filled with my dummy data. Using Daytona as Aero Dancer breaks up the binary when you load the broadband version of the game and the ISP dialer seems to break for me /shrug. Same code tho.

Now to just follow that recv buffer up the path til we are back at BIGSWITCH (hopefully).

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Xiden
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Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#96 » Mon Sep 19, 2022 10:51 pm

Nice work!

ioncannon
Anarki
Posts: 90

Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#97 » Tue Sep 20, 2022 12:08 am

Wooo, got the code going to the BIGSWITCH. So packets are so far [size (2b)][opcode (2b)][data?].

ioncannon
Anarki
Posts: 90

Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#98 » Tue Sep 20, 2022 1:39 am

More progress:

Image

Image

I assume goodcow is the name of the person who got their key generated? Or is it dummy data?

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Xiden
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Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#99 » Tue Sep 20, 2022 3:49 am

ioncannon wrote:More progress:

Image

Image

I assume goodcow is the name of the person who got their key generated? Or is it dummy data?


Goodcow is the name, he had his key saved. The key needs to be mapped out so we can generate others

Cass
MegaDeath
Posts: 225

Re: A friend and I RE'd the KDDI Capcom games but ran into a hardware roadblock. Here's how 15+ games could come back on

Post#100 » Tue Sep 20, 2022 5:24 am

Great job lads some pretty significant progress thanks for grinding away at this.
Last edited by Cass on Tue Sep 20, 2022 5:31 am, edited 3 times in total.

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