I found this:

http://www.whitebream.com/s131.shtml

This IrDA protocol stack is written for small embedded systems that need an easy to implement serial but wireless communication facility.
For instance: the software has been implemented in a wireless handheld barcode scanner.

Specifications:
· Secondary station mode,
· Window size 1,
· Packet size 64 bytes,
· Fixed baudrate 9600bps (SIR)

Protocols:
PHY, LAP, LMP, TinyTP, IAS, IrCOMM.
The sources for this stack are put into public domain.

Unfortunately I found this on the download page:
No files available (yet)

Maybe they put it on if a lot of people asks for.