Accessing routers firmware data from My application

[mykhan]

Hi All!

I am developing VB applications for sometime now but now I am working on some application that can have access over the network. My experience in network programming is not very well.

First of all let me tell you that the router is SOHO based and has a linux kernal based firmware and can be configured through browser.

I want to develop application that can connect to a router on LAN and then extract some information out of it and also provide some information to the firmware from application without accessing it through the web browser. Like for example the log file of the router.

I would like to help getting started with it. I think i will be using winsock dll but am stuck at the start. If any one can give me a clue how to start then i might be doing it to the end.

Another think i want to mention is that I can access the syslog.html file (in urs direcotory) in the firmware by telnetting and accessing the kernal by root. And they are using CGI code to generate the log, but how can i access this from my VB application

Waiting for any help anxiously
Regards
Mykhan

[jplocki]

I'm getting ready to head out the door to work, so this isn't complete, but it's a start. It also uses the WinSock control, since I always use C when writing socket code the "hard way".

General overview:

1. Telnet to the router manually, and do what you would do to view the file. Save this information in a text file that you can refer to later.

2. "Name" each step of the telnet session.

3. Devise some way to keep track of where you are in the session.

4. Send the console commands through the WinSock control, and process the responses until you're through it all.

Here's a brief, simple sample. Pretend this represents a telnet session to view the log file on your router. It's been years since I've been on a router console, so it's obviously not very realistic, but we need this for the sake of this example:

Lines starting with "<" are lines the router sent to you. Lines with ">" are lines you sent to the router.

 
< OK
> view logfile
< 10.1.20.1 outbound to 10.25.1.18
< 10.1.20.19 outbound to 10.26.19.7
< ... etc
< OK

Set up your WinSock control like this:

 
Private m_lStepCount As Long
 
Private Sub Form_Load()
m_lStepCount = 0
End Sub
 
Private Sub cmdConnect_Click()
	With wsRouter
	 If .State <> sckClosed Then
		 .Close
	 End If
 
	 .Protocol = sckTCPProtocol
	 .RemoteHost = strRouterIP
	 .RemotePort = 23			' Telnet port
	 .Connect
 
	Wend
End Sub
 
Private Sub wsRouter_DataArrival(ByVal bytesTotal As Long)
Dim strTemp As String
 
strTemp = String$(bytesTotal, Chr$(0))
wsRouter.GetData strTemp
 
If Not IsError(strTemp) Then
	Select Case m_lStepCount
	 Case 0		' First OK was received
		wsRouter.SendData "view logfile"
		m_lStepCount = m_lStepCount + 1
	 Case 1
		If strTemp <> "OK" Then
		 AppendLog strTemp
		Else
		 wsRouter.Close
		End If
	End Select
End If
 
End Sub
 
Private Function IsError(v_strText) As Boolean
' Do something in here to validate what you're getting from the router
IsError = False
End Function
 
Private Sub AppendLog(v_strText)
' Add this line of text to what you've already got...
 
' But *don't* do it this way...
Static strLog As String
strLog = strLog & v_strText
 
End Sub

This is very basic and oversimplified, but I think it's enough to get you headed in the right direction.

Hope that helps...

[mykhan]

Thanks a lot for your help. I have tried that and had something to work with.

But one thing, you showed the communciation on telnet but actually the communication is all done at port 80 and I want to access the log using 80 and not by telnet.

Another problem I am facing is that I couldnt get the variables which has the log file and its path after the router's IP because the router is using CGI and I am not getting CGI at all. specially in the textarea where the log is pasted, the following CGI code is embedded.

<textarea> <? mutliquery logger:status/log '$01 $02 /n' ?> </textarea>

Now I am not getting that.....

regards

[jplocki]

Got ya... the router uses a little web server for the admin stuff then. I was thinking you said it also supports telnet, and that's easier, to me, since you can send/receive exactly what you would see and do in an actual telnet session.

Whew... to handle the port 80 stuff yourself, then, you're going to need to implement a subset of the HTML protocol in your client, and make requests as a browser would, parse the resulting page code, build the POST message... etc, etc. The CGI you won't have to worry about, as long as you make the "page" requests correctly - that'll happen in the router, and what you get back should be what you want, for free.

Something I've done before for something like this is write a small TCP proxy, connect the proxy to the remote device, and connect the real client to the proxy. My proxy simply uses two Winsock controls, one listens and one connects, and when one receives, it just sends it out the other one. Of course, I analyze and log the data in the process. Then I just connect it all up, do it once or twice using the intended client, and start looking at my logs. From the log, I start building my connection handler, as in my earlier example. In your case, the concept could be pretty similar, just a bit more tedious because you're having to handle the HTML protocol, and possibly actually parsing the HTML page data.

Anyway, if that sounds like a viable option to you, and if you want, I'll dig up and post the code for my little proxy here to help get you started. Heads up, though - the proxy was a tool I needed in a hurry, spent about 20 minutes on it, and never looked back. It works, but it ain't necessarily pretty on the inside.

Let me know...

[mykhan]

Ok Thank you very much...at least the confusion clouds are getting over and I can see ray of hope comming out for me. The position is getting clearer so lets see what else I can do with it. Your help is really appreciated. Beside that I will be waiting for you to paste up your piece of code, in anyway it will be a lot helpful as I am a learner and would take anything for granted

Another query: Can anyone tell me about the API controlling the IP config/all Dos command, both in windowsXP and 98.

Regards
Mykhan Yousafzai

[mykhan]

Another query: Can anyone tell me about the API controlling the IP config/all Dos command, both in windowsXP and 98.

Regards
Mykhan Yousafzai

Done that with a shell command now

[RoyK]

If you want to access the routers data, you can use the SNMP(simple network managment protocol) and just poll the router. All routers support SNMP. Writing a VB SNMP routine is do able but it will take some work. If I had to do it over again, I would buy an SNMP active x control pre-built.

[jplocki]

Hey, mykhan...

Sorry for the delay, here... I had to find the code, and tweak it a bit to make it flexible enough for you to use it without major modifications.

Hope it helps... the code isn't quite as nasty as I had imagined, though it does still fall in the "I need a tool in 20 minutes" category of coding style.

In any case, because of the way this tool works, you couldn't use it for a general purpose web proxy, but I think it'd probably be good enough to do the router stuff you were talking about. If not, my first suspicion would be the connectionless nature of HTTP, so you might have to add code to detect when the client or server disconnects, and reconnect on demand. Maybe you'll get lucky, though, and the router won't disconnect you every time you receive a "page".

Anyway, it's pretty simple... enter the IP/host name of the device, the port you want to connect (80, most likely), and the port you want to listen to (any valid IP port number). Connect your client (web browser) to the to the proxy, specifying the connection port in whatever way the client wants. In IE, it'd be something like: http://127.0.0.1:1200, where the colon separates the host from the port, and the number following the colon is the port.

Hope you find it useful. Heheh, and try to keep in mind that that's not my "production-quality" code in there... I never really expected anyone else to see it, and it works for my needs.

Good luck...