kern/141646: [em] em(4) + lagg(4) + vlan(4) generates ISL-tagged frames instead of 802.1q-tagged frames

[Jeff Blank]

On Fri, Jan 29, 2010 at 02:47:39PM -0800, Jack Vogel wrote:
> What's with the encrypted messages entered in this bug suddenly?

Just base64-encoded plain text--it appears GNATS is not base64-aware.
To summarize (I received a copy directly), Mr. Anishchuk is
experiencing the same problem and suggested a workaround (also posted
to the list previously) involving "ifconfig_emN='-vlanhwtag up'" in
rc.conf.  He also seemed to think it was twice-Q-tagged frames rather
than ISL-tagged frames, which does not match my packet captures.

> An important update - I have root caused this. Turns out its kinda
> interesting.
> The reason there is a problem is due to the stacked pseudo devices, since
> the vlan device is on lagg, and not directly on em, the em driver is not
> getting
> the "event" of the vlan attachment, and thus the vlan hw filter routine is
> never
> run, that routine sets a CRITICAL bit in the control register which
> differentiates
> between ISL and 802 tags... and thus our failure :(
> The question now is what to do about this, I am thinking about this now....

Interesting indeed.  I look forward to a fix (and have alternate
interfaces and -vlanhwtag in the mean time).

thanks,
Jeff