Re: MNT ZZ9000: Various additional drivers available.

[is%netbsd.org@localhost]

Hello,

On Sun, Mar 29, 2020 at 01:11:01PM +0200, Alain Runa wrote:

> I tried “ifconfig zz0 link 68:82:f2:12:34:56 active" just for fun, and was expecting some kind of error, as I didn’t implement this functionality. But instead “ifconfig zz0” shows now:
> address: 68:82:f2:12:34:56
> inet: 192.168.0.10/24 ...
> link: 68:82:f2:00:01:00
> 
> Very confusing. Why do address and link differ? And what does address and link represent in this context?

NetBSD network interfaces have a list of addresses, each tagged
with an address type. NetBSD supports, among others, inet (IPv4),
inet6 (IPv6), and link (what the hardware uses, e.g. the 6byte MACs
on Ethernet, WLAN, and Token Ring or the 1byte addresses of ARCnet).

One of the addresses is the active one, reported as "address", and 
sent to the hardware to set the reception address filter when the 
interface is configured.

This is never (on any Ethernet chipset I'm aware of) loaded from
the chip's eprom, but always read out by the software driver and
written back. (The reason is that there are protocols out there
(e.g. DECnet Phase IV) that have a fixed Ethernet ID per machine,
not per interface, so it must be setable if you want to use them.)

The transmitting direction is software, anyway.

Regards,
	-is