Re: IPv6 forwarding fail = mbuf leak?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>>> What is the interface type on the upstream link?

>> As seen by the host, Ethernet.  The physical layer is DSL (MVL, to
>> be specific), [...].  (In case it matters, the DSL CPE is behind a
>> switch which vlan-trunks that, among other things, to the router
>> host.)

>> The other end is not a mass-market big-ISP head; the DSL is being
>> run over dry copper to a DSLAM at my upstream/employer.

> Wow, how unusual.

:-)

> So:

>   What driver (wm? fxp? vr?) is in use?

The one underlying the vlans?  fxp.  The only fxp - indeed, the only
real Ethernet hardware - in the system.

>   Is the underlying physical interface the same one for the
>   DSl-facing vlan as the house-lan-facing vlan?

Yes (as you can no doubt deduce from the above :-).

>>> Static route, or some IGP, or BGP, or ?
>> Entirely manually-configured statics.
> So this should be easy to reproduce.  I do wonder if it has to do
> with vlans.

I now suspect it may.  I just tried it with a setup involving multiple
real hardware interfaces and have been unable to reproduce it.  This
news is just minutes old, so I haven't had a chance to set up a closer
replica involving vlans (preferably over fxp).  I should see if I have
a vlan-capable switch here (I'm in a different city at the moment,
working with my secondary house LAN, not the primary one this first
occurred with).

If necessary I'll put the system I saw this on back the way it was, but
if it takes that then it'll slow down the hypothesize-test cycle
significantly.

> I dimly remember that ARP used to store a packet when sending an arp
> request, so that it could send it when the reply came.

It does.  I've sometimes started a ping and then, when the destination
host finally answered, getting a ping with RTT in the tens or hundreds
of seconds.

> But that requires freeing the old one (with a queue of 1).

Or freeing the new one, which the high RTTs I've seen imply is what
happens.

> I am unclear on how NDP does this, but it's something else to check.

I'm not sure either.  It's something I should check.

/~\ The ASCII                             Mouse
\ / Ribbon Campaign
 X  Against HTML                mouse%rodents-montreal.org@localhost
/ \ Email!           7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B