Custom client (really custom) and few problems with packets

[maciek134]

Hello everyone. I'm creating custom client (I mean really custom, based on YATC but in Delphi) and I have a problem with few things. At shortcut - I can't get how packets are made. I have read here:
http://tpforums.org/forum/thread-7722.html?highlight=tibia+login
How login packet looks like. But this is login to game server and I want to get characters list first. So I found this:
http://tpforums.ianobermiller.com/forum/thread-4838.html
And with YATC source I menaged to create packet class which helps me to send and parse packets.
But information provided by *DEAD* completly messed up my mind. First example:

recall the that the typical tibia packet is in this format

[2 bytes packet length] [4 bytes adler32] [XTEA encrypted data]

But when I got first packet after sending login packet (this isn't encrypted because encryption is disabled on server side):
[code=delphi]
$31 $00 $A2 $0E $35 $40 $2B $00 $14 $28 $00 $4F $6E $6C $79 $20 $63 $6C $69 $65 $6E $74 $73 $20 $77 $69 $74 $68 $20 $70 $72 $6F $74 $6F $63 $6F $6C $20 $38 $2E $35 $34 $20 $61 $6C $6C $6F $77 $65 $64 $21 $00
-- 1 -- ------ 2 ------ -- 3 -- -4- -- 5 -- ------------------------------------------------------------------------- 6 ---------------------------------------------------------------------------------------
[/code]
As I menaged to read myself:
1 - $0031 - Packet length: 49 which is good without terminating zero
2 - $40350EA2 - Adler32 checksum which I don't use at all
3 - $002B - this appears to be data length (43 in DEC) which *DEAD* don't wrote about
4 - $14 - this should be message type. But it isn't MoTD ($14 is MoTD message type)
5 - $0028 - next string's length: 40
6 - $4F...$21 - message string: Only clients with protocol 8.54 allowed!

So, do I need to add data length (only data, not the length of whole packet) to buffer before sending it? Cuz in YATC source in part when it's sending login packet.
[code=cpp]
void Connection::sendMessage(NetworkMessage& msg)
{
if(m_state != STATE_CONNECTED){
DEBUGPRINT(DEBUGPRINT_ERROR, DEBUGPRINT_LEVEL_OBLIGATORY, "Calling send when state != STATE_CONNECTED(state = %d)\n", m_state);
return;
}

if(msg.getSize() == 0){
DEBUGPRINT(DEBUGPRINT_WARNING, DEBUGPRINT_LEVEL_OBLIGATORY, "Sending size = 0 in message\n");
return;
}

//add message size
msg.addHeader();

//and encrypt if needed
if(m_cryptoEnable && m_crypto){
m_crypto->encrypt(msg);
}


//and add checksum if needed
if(m_checksumEnable){
msg.addChecksum();
}



//wait until all bytes are sent
int sendBytes = 0;
do{
socketret_t b = send(m_socket, msg.getBuffer() + sendBytes, min(msg.getSize() - sendBytes, 1000), 0);
if(b <= 0){
closeConnectionError(ERROR_SEND_FAIL);
return;
}
sendBytes += b;
} while(sendBytes < msg.getSize());
m_sentBytes += sendBytes;
}
[/code]
.addHeader adds only whole packet size before message buffer. So how can I work?

[CristoferMartins]

You need to add Whole packet size in the begining of the packet and after the adler32 you need to add the Data Packet Size.

[maciek134]

Ok, thanks.
And about that weird message type? Because I can see that server is adding $0A byte, but when I recieve it I have $14. Any ideas why?

[tulio150]

you compiled both the server AND client?

If you compiled it to send the error as 0x0A packet and it is sending 0x14, there's something much wrong

[maciek134]

Well, server is just TFS without any encryption, and client, for now is only a little packet parser which doesn't work correctly.
TFS default error message is $0A (0x0A) and I got $14 (0x14). I looked for many ways to explain why is it happening and I ended with nothing (well.. not exactly, I written whole encryption, now I'm turning it on on the server and maybe It'll work fine). Maybe TFS is encrypting message header in different place, I'll never know this

[tulio150]

well, in the otserv sources i have here, at protocollogin.cpp and bool ProtocolLogin:arseFirstPacket(NetworkMessage& msg):

if(version < CLIENT_VERSION_MIN || version > CLIENT_VERSION_MAX){
	disconnectClient(0x0A, STRING_CLIENT_VERSION);
	return false;
}

can you find it?

[tekop]

Remember that YATC is under GPL, so if you make your custom client you will have to give out the sources.

[maciek134]

I know it's GPL, but:
I don't copy/paste code, maybe because I'm writing in Delphi - not in C++. It has whole different structure, only packets are the same, but they are from CipSoft's client. Anyway it's for private use so I can give 'em source.
(If I'll finish packet parser I'll post it here)

[Veritias]

Remember that YATC is under GPL, so if you make your custom client you will have to give out the sources.

Even if it's under GPL you don't HAVE to share the code if you don't want to. Who will find out that you used the GPL licensed sourcecode anyway? It's a question of moral, if you have good moral then yes, you will share. Else you're just a dick leeching on others work and taking credit for it.