svn commit: r242079 - in head: sbin/ipfw share/man/man4 sys/conf sys/net sys/netinet sys/netinet6 sys/netpfil/ipfw

[Andre Oppermann]

On 26.10.2012 14:29, Andrey V. Elsukov wrote:
> On 26.10.2012 15:43, Andre Oppermann wrote:
>>> A> If you can show with your performance profiling that the sysctl
>>> A> isn't even necessary, you could leave it completely away and have
>>> A> pfil_forward enabled permanently.  That would be even better for
>>> A> everybody.
>>>
>>> I'd prefer to have the sysctl. Benchmarking will definitely show
>>> no regression, because in default case packets are tagless. But if
>>> packets would carry 1 or 2 tags each, which don't actually belong
>>> to PACKET_TAG_IPFORWARD, then processing would be pessimized.
>>
>> With M_FASTFWD_OURS I used an overlay of the protocol specific M_PROTO[1-5]
>> mbuf flags.  The same can be done with M_IPFORWARD.  The ipfw code then
>> will not only add the m_tag but also set M_IPFORWARD flag.  That way no
>> sysctl is required and the feature is always available.  The overlay
>> definition is in ip_var.h.
>
> It seems we have only one bit in the m_flags that can be used, so, maybe
> we left it to some things that can appear in the future?

That's what the M_PROTO flags are for:

#define	M_IPFW_FORWARD	M_PROTO2	/* ip forwarding */

of course you have to do the same for ip6.

The M_PROTO[1-5] flags are only valid within a protocol layer.  For
example they get cleared in ip_output() before the packet is handed
to layer 2.

-- 
Andre