PF appears to lock up a machine with a large number of jails

[Kristof Provost]

> On 01 Oct 2015, at 03:06, Felix Gallo <felixgallo at gmail.com> wrote:
> 
> SITUATION 2.
> 
> I then realized that I had TSO enabled on the interface, which seems to
> interact very badly with pf.  So I disabled it and started creating the
> jails again.  Again, it hung the box, but this time seemed to take a lot
> longer to do so (over 100 jails created).
I’m currently looking at the TSO problem with pf.
I think I understand the problem, and it’s limited to bad checksums.
It shouldn’t trigger panics.

I’ve added the lockup with jails to my (ever growing) todo list.
Can you create a PR for this?

Regards,
Kristof