1. A Critical Analysis of the Windows mLAN Driver
Supervisor: Prof. Foss
By: Shaun Miles

2. Overview mLAN system WDM DriverStudio Framework Object model
IEEE 1394
IEC 61883
WDM
DriverStudio Framework
Object model
IOCTL analysis
Conclusion and Questions

3. mLAN

4. mLAN cont. Bus manages itself – no server
PC is useful tool – connection management
Application suit
Driver makes PC look like mLAN device

5. FireWire – IEEE 1394 Flexible serial bus
Fast – good for real time multimedia
Control and Status Register architecture
Standardises offset locations
Node – addressable entity

6. Asynchronous or Isochronous
Asynchronous – control packets
Data integrity
Any time arrival
Isochronous – streaming packets
Continuous stream
CIP – IEC 61883
Ideal for real-time systems

7. IEC 61883.6 High level streaming standard
Audio and music data transmission
Based on mLAN specification
Common isochronous packet – CIP
AM824
8 bit label
24 bit audio/music data

8. Why study the driver? To understand the driver
Platform to investigate mLAN potential
Model driver for future extensions
Audio/video extension?

9. Windows Driver Model Kernel-mode vs user-mode drivers
All kernel-mode drivers – WDM drivers
Supports PnP – device management
Driver – communication pathway – I/O
Layered architecture – driver stack

10. IO request packet
Further specifies the type of request within the major category
All IRPs have a major function code
Categorises type of request
Target device object of the I/O request
Specifies IOCTL code if has major function code of IRP_MJ_DEVICE_
CONTROL

11. I/O Control code Means for driver responding to IO request
Custom codes for special drivers – mLAN
Definable codes with handler routine
Communication pathway
Contained in IRP – IO request packet
Use DeviceIoControl
IOCTL code
Handle to device - GUID
Input/output buffer

12. DriverEntry AddDevice IRP Handler
User-mode space
Application
Ah, a new device
This is the driver to load
WIN32 API
I/O Manger
The kernel
PnP Manger
System Registry
Object Manger – system addressable memory
Driver object
IRP
Device Object
DriverEntry
AddDevice
IRP Handler
New Device!!

13. DriverStudio Driver development tool C++ class library framework
Utility classes
Forms skeleton, backbone of driver
Encapsulates essential driver features
Used by mLAN

14. mLAN driver object model

15. Kernel Streaming Minidriver
Stream Minidriver
Filter driver
Controls adapter
Stream Adapter
Controls stream
Controls hardware
Stream
Data processing of media stream

16. IOCTL code handling

17. mLAN IOCTL codes Grouped by underlying functionality
IEEE 1394 asynchronous requests
IEEE 1394 isochronous streaming
IEC 61883
ASIO – Audio Streaming Input Output
WDM Streaming (KS)

18. WDM Streaming (KS)
Inter-driver communication
KS Minidriver to mLAN

19. ASIO Implements ASIO driver functionality Overrides ASIO classes
Used by applications for audio record and playback

20. Asynchronous IEEE 1394
Asynchronous communication with bus via Firewire bus driver
Allocate/deallocate bus resources
Channel
Bandwidth
Address range
Driver state information

21. Isochronous IEEE 1394 Allocate/deallocate stream resource
Start stream creates WDM minidriver to control stream
Make several requests to Firewire driver to service initial request

23. 61883 Uses 61883 protocol driver Formatting of stream data
Used for plug modelling and connectivity
Plug – input/output
Start/end point of stream

24. Conclusion Driver is clearly structured Modules based on functionality
Compilation problems due to incompatability issues
Analysis done manually, time consuming and messy
Missed out on powerful debugging tool

25. Questions?
Thank you