Server's response to a login request

[CeruleanBlaze]

Hey

Curiosity inspired me to try writing a bot in Python. I've ran into an issue fairly quickly, however, with the logging in. What i'm doing is:

 

Connecting to the server on port 2000

Reading the data from the socket (welcome message)

Sending the username and password, separated by a blank space, prepended by LOG_IN (0x8c).

Reading the server's response

 

From what I understand I read the response to the login and check the first character against LOG_IN_OK and LOG_IN_NOT_OK. The problem is that the response i'm getting is "<\x05\x00h\x01\xae\x0e" (sans the quotes of course). The first character (0x3c/60) is neither LOG_IN_OK (250) nor LOG_IN_NOT_OK (251).

I suppose that i'm missing out a step or sending something incorrectly.

Apologies if it's something simple (it usually always is). If any part needs clarifying just say so.

 

Thanks for your time

Edited March 12, 2005 by CeruleanBlaze

[crusadingknight]

Hrm, the first thing my bot gets is the login message, which used to throw it... not sure if it's raw text you're getting, though.

[Grum]

LOG_IN_OK is not necessarily the first thing you get. I don't even know for sure if there is a specific order in which events arrive.

[CeruleanBlaze]

  Hrm, the first thing my bot gets is the login message, which used to throw it...

Didn't get a login message, just got that data that I pasted - "<\x05\x00h\x01\xae\x0e", where \x signifies hex.

 

 

LOG_IN_OK is not necessarily the first thing you get. I don't even know for sure if there is a specific order in which events arrive.

I thought that might be the case so I read data from the socket over a 10 second interval - that was the only data I got.

[Entropy]

Look in client_server.h for more info about the protocol. That way, by examinign the first byte, you can see what the server sends.

[CeruleanBlaze]

Ping request. Thanks entropy.

[CeruleanBlaze]

Looks like that wasn't my issue (or maybe it was another).

I've replied to the ping (just sent the received data straight back), and then sent the login request:

self.sock.send("%s%s %s" % (chr(el.LOG_IN), self.username, self.password))

I just get no response from the server.

Any suggestions?

[Grum]

You need to send the length of the message too. First, the protocol number (one byte), then the total size of the message (unsigned short, two bytes, little-endian), then the message itself.

[CeruleanBlaze]

Unfortunately i'm still having the same luck.

Here's a log of what i'm sending (shown by '>') and what i'm receiving (shown by '<')

 

< "\x00t\x01\x90Hi, and welcome to Eternal Lands! If you're new to the game and need help, please read the newbie helper guides on the main website. If you would rather learn by doing, talk to the Tutorial NPC, which is at the start point. In addition to that, you can type #help_me and your question to get a live response if there are helpers online. Click on the screen to continue!\n"
> '\x8c\x11\x00Chocolate xxxxxxx'
< '<\x05\x00\xbe\xcf\xe3\x13'
> '<\x05\x00\xbe\xcf\xe3\x13'
< '<\x05\x00g\xd0\xe3\x13\xfb\x01\x00'
> '<\x05\x00g\xd0\xe3\x13\xfb\x01\x00'
Connection closed by server

You can see the welcome message, my login, and my responding to the pings. The connection is then closed (I receive null data from the socket).

 

Thanks to everyone who's stopped by and lent a hand already. I appreciate it.

[frak]

i think u forgot the \0 at the end of login message

[CeruleanBlaze]

  i think u forgot the \0 at the end of login message

I don't think that's required? I see no adding of a null byte to the end.

I tried adding it nonetheless and got the same thing

[Entropy]

Just log what the client sends to the server, then compare it to what your bot sends, and see where is the problem.

[Vegar]

the login message have to be null terminated, otherwise the server will disconnect you

[CeruleanBlaze]

Precisely what i've done - I see no difference. I downloaded elbot (elbot.sf.net) and logged what it sent - it sent the username and password precisely how I did and then got a LOG_IN_OK response directly.

This one has got me scratching my head

[frak]

do u forget to send the heartbeat? (eaten by grue)

[Placid]

EDIT.

 

Send null packets at least every 15 seconds, otherwise you'll get disconnected. (GRUE)

Edited March 14, 2005 by Placid

[Leeloo]

EDIT.

 

Send null packets at least every 15 seconds, otherwise you'll get disconnected. (GRUE)

You're supposed to send a heartbeat packet once per minute. Don't waste the servers bandwidth please

[Placid]

EDIT.

 

Send null packets at least every 15 seconds, otherwise you'll get disconnected. (GRUE)

You're supposed to send a heartbeat packet once per minute. Don't waste the servers bandwidth please

Heh, that was me getting the timing wrong....I'll amend my bots code

Also, I meant 'null' packets as HEARTBEAT packets (They are null packets with the EL constant (from client_serv.h) as first byte)

Edited March 14, 2005 by Placid

[Leeloo]

How can there be a first byte in a null packet?

[Placid]

How can there be a first byte in a null packet?

I think Its my terminology, the packet doesnt actually contain anything, apart from the HEARTBEAT constant, thats what I mean...Sorry

[frak]

it contains the length too =P

and it only need to be sent when u didnt send anything in the last 25 seconds.

[Placid]

it contains the length too =P

and it only need to be sent when u didnt send anything in the last 25 seconds.

ROFL, ok I stand corrected

 

Yes, frak is right, im just talking spurts of rubbish here

[CeruleanBlaze]

Well, i'm getting something now, though i'm not too sure what :S

I tried sending the login message and then sleeping for a second. When I read the data from the socket I get one _long_ piece of data in response - it includes the welcome message and a tonne of bytes. It looks fairly promising as I can see, amidst those bytes, the text `/maps/startmap.elm` - i'm guessing it's telling the client to display that map.

It just strikes me as odd that I should be receiving such a big lump of data.

Here is all the data (again note that \x0a, for example, represents the hex value 0a)

Edited March 14, 2005 by CeruleanBlaze

[Grum]

You're getting a whole bunch of messages from the server in one packet. Since the message length is included in the messages, you can split them and parse them all separately. Have a look at multiplayer.c, get_message_from_server() and process_data_from_server()

[CeruleanBlaze]

Bot logs in fine now

Thanks for all the help everyone, I appreciate it