IPSEC disables TSO

[Kip Macy]

>
> Yes, exactly, there needs to be a smarter test that can distingiush if
> IPSEC is actually in use on a connection or not; I should have been
> more clear about this.  The problem is that I have zero knowledge
> about IPSEC, so I have no idea how to do this.
>
> I'm worried that people will compile IPSEC into the kernel to run an
> encrypted tunnel (or the TCP MD5 signature stuff for BGP), and
> then be rather surprised that their their "normal" TCP performance
> stinks.

Maybe file it as a PR?

-Kip