Re: pfil_add_ihook() with PFIL_IFNET

> But, surely, it seems to me the simple thing to do is to just grep for
> PFIL_IFNET_ATTACH and PFIL_IFNET_DETACH and look at the surrounding
> code to see what circumstances they're used in.

Yea just a quick look, they only really appear here.

src/sys/net/if.c:755: pfil_run_ifhooks(if_pfil, PFIL_IFNET_ATTACH, ifp);
src/sys/net/if.c:1527: pfil_run_ifhooks(if_pfil, PFIL_IFNET_DETACH, ifp);

Which are both within *if_initialize* and *if_detatch* respectively, and
those methods are only called to either attach or detach an interface of
some kind, virtual interfaces as well. Something else interesting, looks
like when a device driver initialises itself, it defines an object of
type *struct
cfattach* by usually invoking some variant of the *CFATTACH_DECL_NEW*
macro. And within this structure are a bunch of methods, and what concerns
us is *ca_detach* and *ca_attach*, so I guess that is kinda the bottom of
the chain.


On Mon, Mar 24, 2025 at 2:37 PM Mouse <[email protected]> wrote:

> > when I create hook with parameter PFIL_IFNET what actions should
> > invoke hook with PFIL_IFNET_ATTACH or PFIL_IFNET_DETACH ?
>
> I don't actually know, though my guess would be an interface attaching
> or detaching (eg, USB Ethernet plugged in or removed).
>
> But, surely, it seems to me the simple thing to do is to just grep for
> PFIL_IFNET_ATTACH and PFIL_IFNET_DETACH and look at the surrounding
> code to see what circumstances they're used in.
>
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