Do wifi adapters do switching internally or do the packets go through the OS networking stack?

Question

According to Does wireless traffic in a network still have to go through a switch?, packets sent between devices connected to the same AP still goes through the AP. My question is how exactly does the AP handles the switching of such packets, or more precisely, what is the path taken by these packets? Do they gets handled inside the wireless adapters? Do they get handled by the driver? Do they travel all the way to the OS network stack and gets handled there?

I'm particularly interested in whether they go through the network stack. Since if they do then it is possible to use things like netfilter to filter L2 traffic on the WLAN. (And if they don't it won't be possible)

Answer 1

My question is how exactly does the AP handles the switching of such packets,

Switching forwards frames by (learned) destination MAC address. Most WAPs use a wired backhaul, so they'd forward selectively between wireless and wired nodes.

or more precisely, what is the path taken by these packets?

With both source and destination connected to the same WAP, the frame just hops across the WAP.

Do they gets handled inside the wireless adapters?

That depends on the implementation of the WAP which is off topic here (for being speculative). Basically, cheap/simple WAPs use more software, more expensive/sophisticated ones more hardware.

Do they get handled by the driver?

Implementation specific, off topic.

Do they travel all the way to the OS network stack and gets handled there?

Not likely. Switching just requires L2 (and L1 below), so there's no need to involve any more of the stack.

Do wifi adapters do switching internally or do the packets go through the OS networking stack?

Wifi adapters (=NICs) don't switch. WAPs do.