Problems with OpenBSD dhclient

[Sam Leffler]

Randy Bush wrote:
>>>More serious is that I can't roam. When I move between APs, dhclient
>>>exits and I need to manually re-start it. I lose my SSH sessions. Ugh!
>>
>>This should not be happening; dhclient should get a disassociate event, 
>>drop the lease, then get an associate when you join the new ap and 
>>immediately grab a new lease.
> 
> 
> aiii!  this was merely a layer-2 re-association, no change at layer-3.

I mis-spoke; dhclient trys to re-acquire the current lease.  This is 
exactly what happened before except it should now happen _immediately_ 
on being notified of a re-association to the same ap or an association 
to a new ap.  Actually I could check for a re-association and not 
re-aquire the lease to reduce the overhead but regardless this should be 
ok (so far as I understand the protocols).

The previous code polled for these events.  This made it prone to 
missing fast re-associations (instead falling back to various timeouts) 
and slow to respond when roaming.  The new code had been working 
correctly; something has clearly changed and I'll fix it asap.

	Sam