[Cake] openwrt build with latest cake and other qdiscs

[Jonathan Morton]

>> I would humbly suggest that we should just get a numerical option for cake to specify the overhead...
> 
> That is in the plans, along with keywords in tc as mnemonics for the most common configurations.

I’ve just pushed support for an overhead parameter; both cake itself and the iproute2 module.  I took the opportunity to put in a minor optimisation for the cell-framing compensation as well.

The iproute2 support isn’t as complete as I’d eventually like.  However, you can specify a numerical overhead (positive or negative, within sane limits) independently of whether ATM framing compensation is turned on or off.

There are also two “easy mode” keywords: “raw” is equivalent to “noatm overhead 0”, and “conservative” means “atm overhead 48”.  The latter will almost certainly overestimate the actual overhead.

The help text for cake also now indicates the default options more clearly.

Also pushed is a one-line build fix for iproute2.

 - Jonathan Morton