Driving a USB Rocket Launcher from Perl in

Driving a USB Rocket Launcher from Perl in User Space Mike Schilli, Yahoo! 06/23/2009 YAPC, Pittsburgh, PA

Goals • How can I use USB gadgets on Linux, even if they only come with a Windows driver?

USB: A versatile technology

Limited Fun on Windows

Unlimited Fun with Perl • Defend your Cubicle • Burglar Alarm with Web Cam and Rocket Launcher

USB Architecture

USB Hierarchy

Plug it in …

USB Architecture

Plug it in …

Device Drivers • Often not available for Linux, just for Windows/Mac • Hard to write • Highly dependent on kernel version • Vendors don’t want to bother with niche markets

USB Architecture

libusb • Drivers in User Space • http: //libusb. sourceforge. net • Problem: How to find a device?

Plug it in …

USB Architecture

Install Everything

USB Rules to set Permissions

Rocket. Baby

Plug it in …

Rocket. Baby

USB Architecture • Control Transfers (config & control) • Bulk Transfers (large quantities of timesensitive data) • Interrupt Transfers (small amounts of timesensitive data) • Isochronous Transfers (real-time data at predictable rates)

Reverse Engineering Efforts • Rocket. Baby comes with Win XP driver – Protocol sniffed out with USBSniff –. DLL code investigated with IDA Pro Disassembler (see references) – Control Transfers for turn/raise/lower/fire – Bulk Transfers for reading status

Reverse Engineering Efforts • Control Transfers (config & control) • Bulk Transfers (large quantities of timesensitive data) • Interrupt Transfers (small amounts of timesensitive data) • Isochronous Transfers (real-time data at predictable rates)

Rocket. Baby Control Codes

Swivel/Raise Rocket Tower

Read Status

Demo

CPAN Module Device: : USB: : Missile. Launcher: : Rocket. Baby

Demo • Attention in the splash zone! • Incoming rockets!

References • Video “The Great Office War” http: //www. youtube. com/watch? v=p. VKn. F 26 q. FFM • Alessandro Rubini, Linux Device Drivers: http: //lwn. net/images/pdf/LDD 3/ch 13. pdf • “Essential Linux Device Drivers”, Sreekrishnan Venkateswaren, Prentice Hall, 2007 • Rocket. Baby Reverse Engineering Efforts http: //dvlabs. tippingpoint. com/blog/2009/02/12/python-interfacing-ausb-missile-launcher