Sort of NDIS Intermediate Miniport on Mac OS X

Question

We have a solution of an intermediate network layer which is currently implemented as a NDIS IM on Windows. I am investigating how this thing could be ported to Mac OS X.

Ideally, it should be an intermediate driver/kext right on top of the ethernet-capable adapter, and below any IP/ARP/whatsoever, operating only with ethernet frames.

Some tutorial/sample would be preferred, something like the passthru sample from the WDK, although any hints would be appreciated.

No, this is not a filter/firewall, it's not vpn, it's a completely new and quite complicated intermediate layer operating at that level.

Answer 1

I suggest you to read Network Kernel Extensions Programming Guide. See NKE architecture in "Network Kernel Extensions Overview" section. Looks like you need an Interface Filter or may be even a virtual interface.
Also see the "Networking" chapter (chapter 13) in the "OS X and iOS Kernel Programming" book (by Ole Henry Halvorsen and Douglas Clarke). As far as I remember there was an example of simple ethernet controller driver.