Mock Device connecting through USB

Question

I have a device and the drivers for this device. What I would like to do is build an application that mocks a USB device to communicate with a third party application.

More specifically, I am attempting to build an application that can mock a USB device that mimics a Microsoft Zune. I want to make it so my application can register as a zune device and then communicate with the client. I have added several DLL's to my application in order to attempt to determine the calls that tell the software a connected device is a legitimate zune, but so far I haven't had much luck.

I'm new to this type of development - that is mimicking hardware devices, and I'm not very experienced in importing dll's that were written in C/C++. I am using Visual Studio 2010 (.net 4.0) to develop my app, and I would appreciate any help anyone can offer me towards mimicking the hardware. I do have the device drivers, which Visual studio refuses to reference directly. I also have an actual physical device, so I can see what the drivers are that it uses in Device Manager.

The goal is as follows

1. Application registers itself as a usb device, mimicking a Microsoft Zune in a similar fashion to how Virtual Clone Drive mimics a DVD player.
2. Application is recognized by zune client as a valid microsoft zune.
3. Zune Software works with application as it does the hardware device (syncing, etc)

Answer 1

Are you able to replace the DLLs used by the zune client software with your own DLLs? In that case, you could wrap the original DLLs with your DLLs and intercept the operations.

Update: To find out the signatures of the functions in the DLL, take a look at the Dependency Walker tool, which will list the exported functions (and lots of other information). I'm guessing you will want to write your replacement DLL in C.

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Otherwise, you'll have to write drivers that register a USB device with the proper endpoints. I'm not sure how to do this on Windows - I've only done USB coding on the firmware side, not the driver side. You should be able to use any tutorial for creating a Windows USB driver, like Getting Started with USB Driver Development

Zune specifics information might also be useful. Perhaps this blog post and its sequels could help: Inside the Zune/USB Protocol: Part 1

Answer 2

I just found something called the Device Simulation Framework, which might be exactly what you need. It will still require significant research into how USB works to finish your solution, though. And probably still typically done using C or C++.

The Zune uses a modified version of the MTP protocol called MTPZ, but I found this sample using the Device Simulation Framework to simulate a regular MTP device. It's called The MTP Device Simulator. I can't tell if source code is available.