Intercept and modify USB packets

Question

The project is as follows;

I would like to create an application that will be able to see packets going to a USB device. When a certain bit of data that is known is sent to the device, the returning data will be intercepted and modified before the application requesting it, gets it. I have used a USB sniffer to see the packets being sent and I know exactly what bits need to be changed. My two questions are;

1. Is this a possible software solution?
2. Will this have to be a hardware solution?

Additional Information –

• The USB device uses a FTDI245R chip for communication. I know the VID and PID of the device.
• I have experience programming in vb.net and C# but I have never done anything with USB
• I would like the application to be able to have a number entered and changed to hex data and that is what would be sent to the device. The number being entered would be changed frequently.

Any input is appreciated.

Answer 1

It sounds to me like you want an upper filter driver to the FTDI driver. I don't know what class or type of device you are using or if it has a vendor specific driver or not, but here is a sample that shows how to create an upper filter to a vendor specific driver . This example uses the OSRUSBFX2 device and sample driver in the WDK, you'll want to change the code to work and interface with the FTDI driver instead.