[Cake] resubmitting cake for 4.16

[Jonathan Morton]

> On 26 Jan, 2018, at 8:30 pm, Dave Taht <dave.taht at gmail.com> wrote:
> 
> After catching up on my mail, the only thing that still looks shaky
> was the hard_header_len controversy (?)

Yes, I need to refactor the packet length handling in general, especially with respect to the new ack-filter code which ends up referencing packet lemgths a lot.

 - Jonathan Morton