I have serious doubts. Having worked with switch ASIC vendors before (Marvell, Broadcom), they require you to sign a mile long NDA before you can even access da

I have serious doubts. Having worked with switch ASIC vendors before (Marvell, Broadcom), they require you to sign a mile long NDA before you can even access datasheets. If you can get the switch vendor to release a GPL archive (which is often a struggle in of itself) I have never seen them release the source code to manage the switch ASIC. That's always built as an out-of-tree module which is not released as part of the GPL archive. Many switches are not even running Linux, it's quite typical to see eCos, VxWorks, or an RTOS (e.g. ThreadX) on a switch. tl;dr - even if the switch runs Linux (many don't), it is very unlikely you will have the datasheet and/or reference implementation for managing the switch ASIC