kern/58554: add filtering by mac address

[scole%sdf.org@localhost]

>Number:         58554
>Category:       kern
>Synopsis:       add filtering by mac address
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Sun Aug 04 16:25:01 +0000 2024
>Originator:     scole
>Release:        10.0 STABLE
>Organization:
>Environment:
NetBSD dstar.dstar.net 10.0_STABLE NetBSD 10.0_STABLE (GENERIC) #0: Sun Jul 28 14:24:49 PDT 2024  scole%dstar.dstar.net@localhost:/home/scole/nbsd/cvs/10_0/obj/sys/arch/amd64/compile/GENERIC amd64
>Description:
There should be a way to filter network traffic by MAC address in NetBSD.

Other OS's (linux/iptables, freebsd/ipfw, openbsd PF/bridge) have this capability.

If npf is NetBSD's preferred packet filter, it would be nice to be able to manipulate rules that do this using npf/npfctl/npf.conf.   If that is not possible, some new stand-alone utility (mpf?) would be better than nothing.

>How-To-Repeat:

>Fix: