if_flags usage etc.

[Robert Watson]

On Tue, 24 Jan 2006, John-Mark Gurney wrote:

> sthaug at nethelp.no wrote this message on Tue, Jan 24, 2006 at 23:15 +0100:
>>> We should probably better document the interface "interface". if we are
>>> going to (as Sam suggests)
>>> do some cleanups we might as well consider what other changes should be
>>> put in at the same time.
>>
>> A couple of other suggestions:
>>
>> - For software routers (quagga, zebra etc.) it would be very nice to
>> have "link up" / "link down" notifications to the routing process(es).
>
> already supported, either through kqueue, routing socket, or devd (I 
> believe)...

However, I believe some interface drivers don't generate these events. 
Drivers not supporting a specific event delivered by an interrupt probably 
need to learn to poll for state changes so that they can generate an event.

Robert N M Watson