tcp hostcache and ip fastforward for review

[Petri Helenius]

popsong old wrote:

>Ah, my fault. I didn't read your patch carefully and assumed that ip
>fastforward do flow caching as ip_flow does. However, I think ip flow
>caching is a good thing and maybe implementing it in ip fastforward is
>a good idea.
>
>  
>
Caching flows has mixed results, it works for you if you have to keep 
flow-based state
like in firewalling situations but usually takes performance in generic 
packet forwarding
because of the great number of flows per host in current public Internet.

Pete