[Cake] allocate_src allocate_dst

[Kevin Darbyshire-Bryant]

Have to say, my perception is that I’ve a small cpu usage improvement for my use case with these changes.  Then I would expect that ‘cos I use ‘dual-srchost’ on egress and ‘dual-dsthost’ on ingress, so I’m saving running the dst/src host allocation code on egress/ingress respectively.

Of course for the standard ‘triple-isolate’ things will be slightly slower ‘cos of the conditional flag setting.

Cheers,

Kevin