DDraceNetwork - developer

DDraceNetwork

Development / developer

Development discussion. Logged to https://ddnet.tw/irclogs/ Connected with DDNet's IRC channel, Matrix room and GitHub repositories — IRC: #ddnet on Quakenet | Matrix: #ddnet-developer:matrix.org GitHub: https://github.com/ddnet

Between 2020-02-10 00:00:00Z and 2020-02-11 00:00:00Z

[ddnet-maps:master] 1 new commit

bba7abb M Redefined, A Soap - ddnet-maps

Send custom messages to people when they join the server: https://github.com/d3fault/ddnet/tree/onjoin-messages --- rushed as fuck sloppy code dgaf

DDraceNetwork, a mod of Teeworlds. Contribute to d3fault/ddnet development by creating an account on GitHub.

pro coder

wow ur ugly

[ddnet-web:master] 1 new commit

cfee5e6 Update 2020 server costs - def-

'r_anal_get_function_at’ was not declared in this scope Someone wasn't thinking while naming their functions

radare2 is full of that

did you see r2ghidra?

18:04

radare2 ghidra and cutter make such a nice combo

r2ghidra? no

18:06

I heard that ghidra is the much better disassembler

18:06

what's r2ghidra? some sort of brdige between r2 and ghidra?

It allows you to use ghidras decompiler in r2, so yes

uh nice

I'm really loving r2 and cutter

18:12

It might not be as fully featured as some of the other tools but it's very capable

I like that its interface is much slimmer than all these other tools'

what r u guys using these tools for?

reverse engineering

hm what stuff do you reverse engineere?

18:45

Uhm im not sure if i should open a issue but there was something wrong with the server for sure

18:48

https://paste.zillyhuhn.com/77

18:49

there were many Error sending data disconnects.

18:49

it is a known issue for sending votes but there were no vote changes so its something new

aaaaaaa

19:23

its the votes

19:23

yea

19:24

if players have bad connection packets often get dropped

19:24

but they are vital

19:24

so they get resent

19:24

and that overloading the buffer

no its not the votes

https://paste.zillyhuhn.com/vB

19:35

thats how votes would look like in the logs

@ChillerDragon I like looking at teeworlds bots

oh nice

19:51

sounds fun

19:51

do you have a specific process that you use? Do you diff against the unmodified base src?

I like to work backwards from strings

20:16

e.g. I know --silent is a string somewhere in the tw code, and what references that is the main function

how to anti-re-protect against @Learath2 in 5 easy steps

If you remove all the strings, sure

20:20

Should store all strings encrypted, that should slow me down

20:21

To be even more annoying, encrypt them all with different keys

20:21

r2ghidra is sadly not good enough yet

in what way?

20:23

have you tried using ghidra's SLEIGH before btw?

haven't really used ghidra yet

20:24

r2ghidra is having trouble mapping the types between ghidras decompiler and r2

@heinrich5991 and what do you use these tools for or do you keep that secret o.O?

20:40

@Learath2 so it’s mostly Windows executables that you look at? Any easy/interesting bots for me to start? I am kinda lazy but I would love to learn it a bit. Such a useful and interesting skill.

tried looking at some old games, nowadays doing ctf challenges, mostly

20:42

also looked at teeworlds servers occasionally

20:44

try some easy challenges first, maybe? I don't know how to start

@ChillerDragon windows, linux, doesn't really matter much

also wanted to reverse-engineer the aoc "binaries" with ghidra

20:44

but didn't get around to that yet

You can grab crackme's from a lot of places they come in a lot of different difficulties

20:46

There was that one teeworlds server with a hidden backdoor rcon password, you can try that

@ChillerDragon thats how votes look like in the log when they got added, yes

20:47

Not when they get sent to the client

https://youtu.be/kx2xp7IQNSc This is a decent talk

Ghidra - Journey from Classified NSA Tool to Open Source

20:48

it's also ironic that the NSA is giving a talk at blackhat

what's that?

20:49

the talk

Introduction to ghidra and the motivation behind how/why they made it

There was that one teeworlds server with a hidden backdoor rcon password, you can try that

@Learath2 lol like a teeworlds ctf? Where?

21:14

@fokkonaut aren’t they sent to the client after the server type changed and thus they get added?

ye

21:14

they get added (loaded from a config)

21:14

and then sent to the clienzs

Yes

but also sent on connect

So the Crash I found was not on connect or vote

it can also happen after connect ofc

When?

bad Internet -> more resends

Hm

because more drop

It was a bunch of people

see

21:15

well

21:15

that doesnt matter

So you assume it’s the known Vize issue?

when the buffer is full, which can happen with thousands of votes + resends etc, then also other people receiving packets like emote can drop

I see

21:16

Do votes get send multiple times?

(I guess, this is afaik about the networking)

I thought only once

no, but they get resend if failed to send (vital)

21:17

like any vital packet

Idk anything about this stuff

21:17

So vital packets get resend until they get a ok response?

yes

That would mean a bunch of people play a while and all the time the votes failed to send and then something happend that caused to much traffic and all those players get a disconnect?

everybody can in this case

21:19

not only those who receive the packet i think

21:19

because there is traffic at all time, to every client

21:20

This is a problem for rainbow in 0.7, which I couldnt find a solution for yet

21:20

Because rainbow in 0.7 can not be handled in the snap anymore, instead is sent as a net object

21:20

(skin change)

21:21

increasing the buffer, which i did, is of course a solution, but it only increases the time until the buffer is full, so disconnects still happen, but a bit later mostly

21:22

i had a player with 200+ ping on my server, and gave rainbow to myself only. This caused multiple people to disconnect (error sending data), not only him. But when there were only people with ~40 ping, it was possible to give rainbow to multiple people, as they do not have to get resent

21:23

-> not filling the buffer

Ah interesting

21:23

Ok really all seems to be one issue

21:24

That’s why I asked before opening a GitHub issue

thanks for explaining and sharing your experience @fokkonaut

np

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