DDraceNetwork - developer

@Robyt3 is there a good way to check if CNetClient::Recv() was called for the master server or a normal server? and does it even make a difrence

n0Ketchp

[ddnet/ddnet] Pull request opened: #9722 Update spanish.txt for 19.0

Checklist

[ ] Tested the change ingame
[ ] Provided screenshots if it is a visual change
[ ] Tested in combination with possibly related configuration options
[ ] Written a unit test (especially base/) or added coverage to integration test
[ ] Considered possible null pointers and out of bounds array indexing
[ ] Changed no physics that affect existing maps
[ ] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-ad...

or even better is there a way to not look for a master server at all?

ZerolAcqua

[ddnet/ddnet] Pull request opened: #9723 fix issue where 'allow unused' shortcut caused button hiding to fail

Closes #9705

fixed the issue where the shortcut caused the button hiding to fail
replaced the integer flag for m_AllowPlaceUnusedTiles with an enum class

All integer flags in m_AllowPlaceUnusedTiles have been replaced with the corresponding enum values from EUnusedEntities.

Parts that previously relied on implicitly converting -1 and 1 to true have been replaced with isAllowPlaceUnusedTiles().

Checklist

[x] Tested the change ingame
[ ] Provi...

david loves Jellycar Worlds

@Robyt3 is there a good way to check if CNetClient::Recv() was called for the master server or a normal server? and does it even make a difrence

Iirc master server traffic in ddnet is handled via https now so the client shouldn't be receiving any of it via this function (?)

hmm

03:05

do you have any idea of any meathods of comunicatson from a normal server to the client outer then that funcson

03:06

as its inconsitent still

What is the context this looks interesting

fuzzing

03:06

im trying to fuzz the networking system

When you join .6 server from ddnet client i believe it is all handled through this engine/network* stuff

with afl++

:D

hmm ok is there a download for a .6 server anywhere?

Ddnet is 0.6, it comes with code for client+server

oh ok

david loves Jellycar Worlds

do you have any idea of any meathods of comunicatson from a normal server to the client outer then that funcson

What is the code that you are trying to find?

basicly ive made it so that the recv funcson always returns the same sequnce of packets but it still doesnt work the same if i simply copy the packets from a normal server

Are u accounting for the tokens?

what tokens?

03:09

so probaly not

Wait leme get my laptop

ok

@david loves Jellycar Worlds u probably seen this already but, tw 0.6 protocol begins with a handshake where the server tells u ur token that it calculates from ur ip and its seed and stuff to work against spoofing

ohhhhhh

03:12

that exsplanes a lot

and every packet thats exchanged after that needs to contain that token

thanks

03:12

so thats what that token i keep seeing is

thanks so much

np

wait so the sever tells you your token so why doesnt the emulated packets tell the client there token

the connection sequence for tw 0.6 is like this 1. client sends server a connection request 2. server sends client an ack pkt basically with the token it calculated from its seed+clients ip 3. client sends that token back to prove it isnt spoofing then the rest of the connection stuff continues

03:15

https://chillerdragon.github.io/teeworlds-protocol/06.html

can you tell me where this happens?

03:15

also whats spoofing (edited)

spoofing=malicious people sending junk from fake ips to make people lag

ah ok. wait fake ips? how in the world do you fake a ip

03:16

also isnt that basicly just ddosing

yes

why cant fake clients do that too

what is a fake client?

the fake ips

03:17

why cant they pretend to be a real client

they can pretend i guess but the replies wont reach them

why not?

if i send u a letter in the mail and give a fake return address

03:17

will i get ur reply?

ah ok i see what you mean by fake ip now

03:18

do you know what funcsons handles this?

yeah sec

thanks

03:18

and also what verifys that the packet has the correct token

03:19

on the clients side

https://github.com/ddnet/ddnet/blob/master/src/engine/shared/network_conn.cpp#L326 for example this is one place where it checks toekn

david loves Jellycar Worlds

and also what verifys that the packet has the correct token

afaik the token check is mostly happening on server side because this is usually where it needs to protect against attacks

hmm well im faking a server not a client

if u are just trying to do fuzzing for other purposes u could just sv_vanilla_antispoof 0 or something

ah ok

03:21

is there ANY token checks on the client

then connect with an old client that doesnt use tokens

03:21

tbh idk lol

03:21

old versions of tw 0.6 didnt have any concept of tokens

03:22

but that isnt useful for u probably

noby

then connect with an old client that doesnt use tokens

im faking the server. downgradeing would kinda moot the point of fuzzing

right

03:22

can ur fuzzing tool hard code the token?

no but i could

it is calculated based on the server hash and the client ip

by just removing all of the token checks

that works too

and as far as i can tell from looking at the hex data the first 2 bytes are the packet type right?

depends

03:24

do u have the wireshark dissector tool thing

as it crashes on packet six wich starts with like 15 FFs

eh?

noby

do u have the wireshark dissector tool thing

no im just dumping the packets

get that it will help u

03:25

https://github.com/heinrich5991/libtw2/tree/master/wireshark-dissector

libtw2/wireshark-dissector at master · heinrich5991/libtw2

Some Teeworlds stuff in Rust.™. Contribute to heinrich5991/libtw2 development by creating an account on GitHub.

and by dumping i mean dumping the output from recv

makes tw traffic more sensible

this is the first 6 packets. after the 6th it crashes currently

message.txt

2.16 KB

03:26

and i have no clue why

what crashes

the game due to unknown NETADDR type 0

03:26

or sometimes -1mil something

probably dumb q but, where are u printing this info from?

and sometimes it doesnt crash

this seems like a mix of relevant and irrelevant packets

noby

probably dumb q but, where are u printing this info from?

its the fake packets im sending recv

03:28

and its from a bunch of packets i got sent from recv

the fffff... 696578742D

03:28

is a reply to server inforeq

03:28

probably isnt even necessary for fuzzing connection

03:29

10000002544B454E8FB79E2B

that looks weird edit; nvm actually (edited)

wait a reply? thats odd im only logging the data from Recv

mm

namely here

03:30

(that adds its length as 2 bytes and then the packets data to a file that im reading from now)

its been a while but from what i remember, client sends this: 10 00 00 01 54 4B 45 4E FF FF FF FF then server sends: 10 00 00 02 54 4B 45 4E xx xx xx xx (aka token) then client sends: 10 00 00 03 xx xx xx xx (edited)

hmm heres my code for converting it into hex if thats broken

why not just printf("%02x

i didnt know that exsited

03:33

can you send the full funcson

03:34

im still pritty new to c++

lazy code but like

for (int i = 0; i < size; i++)
    printf("%02x ", (unsigned char)data[i]);
printf("\n");

one sec while i rebuild

i would suggest using heinrichs tool it gives u useful info like this

ah wait i didnt relise that was ment sufficly for the game lol

ye

03:38

it is just wireshark plugin that understands this game protocol

ok yep there was indded a bug in my code

message.txt

3.03 KB

03:40

the firs packet is still odd but the second is what you said the server sends back

read my edit,i was wrong about the second one

david loves Jellycar Worlds

ok yep there was indded a bug in my code

the first one here still seems odd though? am i missing something

yea thats what i just said. idk why its there but aparently net_udp_recv(m_Socket, &Addr, &pData); returned that first for some reson

03:42

and i have ANSL so i know its not a oob read or something

u should try using some network capturing tool to dump the raw traffic to rule out the logging as a possible source of error

03:42

idk whats ansl

03:43

could just tcpdump "udp and port 8303" -w test.pcap it

oh wait i mean ASAN

oh

03:43

yea

sorry keep frogeting the acrinum

lol

noby

could just tcpdump "udp and port 8303" -w test.pcap it

sure one sec

1

03:45

ok had to grant wireshark admin 15 times before it would stop bugging me lol

noby

could just tcpdump "udp and port 8303" -w test.pcap it

how do i do that?

wireshark is okay too

oh wait is that a linux command lol

wireshark is just a gui around tcpdump

03:45

basically

03:46

idk alot about windows

fair but ill use tcpdump as i dont want to give you all my port info lol

u dont have to give me any info

yea but im gonna give you the .pcap file arent i?

u could if u want lol

also wait is this a windows or linux comand

what is port info

03:47

tcpdump probably works on any system if u install it

noby

what is port info

wdym?

david loves Jellycar Worlds

fair but ill use tcpdump as i dont want to give you all my port info lol

u said it

oh i ment all the packets being sent by all my ports

ohh

i only want you to see ddnet packets lol

there is a way in wireshark to only export certain packets

oh? how?

03:48

i dont use wireshark much

wtf noby

?

iam using osx on this laptop but here its, file->export specified packets, then u can mark packets or only chose selected

03:50

then u can open the file u exported to make sure its only the ones u want

louis

wtf noby

wtf nouis

ah ok ill probs just use tcpdump

whatevers easiest

yea that should be easyer

was more just saying that its an easy way for U to see the traffic

03:51

not about sending it

ah true

03:53

huh odd it didnt capture any packets

did u pick the right interface

noby

did u pick the right interface

wdym?

how do u see moderator chat LOL

03:54

ah

vencord lol

1

run tcpdump, then do a connection to the server

03:54

assuming default port 8303

wait vencord is agenst the rules?

idk

03:55

not here lol

yea i didnt think so

maybe discords rules though

03:55

not sure

hmm

david loves Jellycar Worlds

wdym?

and i mean, if u are hosting server locally, it may be trying to connect through loopback

im not im just joining a random server here

oh

03:57

was it a server that was running on port 8303?

how do i check

when u in browser

03:57

it tells u

03:58

u could just "udp" and skip the port thing if ur not sure

there we go

then u can open that pcap in wireshark if u wnt to inspect it

here

test.pcap

51.1 KB

or that

let me check what my code captured

(that was 8303 though lol)

yea i just chose a server that had that port this time

1

04:03

looks about the same to me

message.txt

3.02 KB

what does it mean fake packet receved

that means im faking a packet with the given data

04:03

ie im pretending like the server sent it

i am probably missing something here but, shouldn't the server not be sending anything until the

10 00 00 02 54 4b 45 4e 8f b7 9e 2b

04:04

what is the thing before that

acording to what you said just a little bit ago yes

noby

what is the thing before that

idk but it was a packet from net_udp_recv(m_Socket, &Addr, &pData); in recv

maybe the debug print in recv should either display or check against the address its being recvd from

04:06

if its just stun traffic or inforeqs or other stuff then it probably(?) isnt relevant for what u are tryin to do

good idea. now to figger out how to get the ip thats sending the data

iirc net_udp_recv accepts a ptr that it populates with that info

04:08

and there is probably another routine in system.cpp that formats a NETADDR in a readable way but i forget which. if not theres always inet_ntoa

is that the socket or the netaddr (edited)

netaddr

04:11

ah its

04:11

net_addr_str

04:11

if u want to display it

that should work fine

that should do

04:12

something

04:12

im not sure what honestly lol

04:12

printf expects a format string as its first argument

04:12

may crash

@murpi can sv_practice_by_default be enabled on test servers

im also probably wrong but in case im not, try smt like

char buf[64];
net_addr_str(&Addr, buf, sizeof(buf), true);
printf("from %s\n", buf);

(edited)

I'm in the middle of troubleshooting our servers

04:14

literally on fire rn

didnt even connect to any server

04:14

and yes your right

u crashed murpis servers

04:15

gg

yay

loll

i win murpi

04:15

/jk

or did i?

idts