net.inet.ip.forwarding and net.inet.ip.fastforwarding

[Sam Leffler]

Matt Emmerton wrote:
>>Hi guys.
>>
>>What's the difference between net.inet.ip.forwarding and
> 
> net.inet.ip.fastforwarding  ?
> 
>>What's the role of net.inet.ip.fastforwarding ?
> 
> 
>>From inet(4):
> 
>      IPCTL_FORWARDING      (ip.forwarding) Boolean: enable/disable
> forwarding
>                            of IP packets.  Defaults to off.
> 
>      IPCTL_FASTFORWARDING  (ip.fastforwarding) Boolean: enable/disable the
> use
>                            of fast IP forwarding code.  Defaults to off.
> When
>                            fast forwarding is enabled, IP packets are for-
>                            warded directly to the appropriate network inter-
>                            face with a minimal validity checking, which
>                            greatly improves the throughput.  On the other
>                            hand, they bypass the standard procedures, such
> as
>                            IP option processing and ipfirewall(4) checking.
>                            It is not guaranteed that every packet will be
>                            fast-forwarded.
> 

This quote is out of date; on current fastforwarding is purely an 
optimization path--if the packet requires features not supported by the 
fast path then it's processed normally.

	Sam