pfsync: Insert static trace points

[kp]

Summary

Make it easier to debug & intrument pfsync.
The fbt provider isn't very helpful, because many important functions
are static. Introduce a handful of interesting probe points.

Sponsored by: Orange Business Services

[eri]

Can you add some text to the manual pages for documenting the feature? Possibly linking to some example?

[kp]

In D17994#389260, @eri wrote:

Can you add some text to the manual pages for documenting the feature? Possibly linking to some example?

I've got 'write a dtrace man page for pf/pfsync' on my todo list, but I'm waiting until I commit the pfsync changes. There's still some discussion going on, and if the implementation ends up changing the probe points will too.

[glebius]

Thanks.

P.S. In pf itself, the dtrace probing should just substitute existing printf(9) debugging.

[kp]

Abandoned in favour of D18373.

These trace points are closely tied to the pfsync improvement approach that has been abandoned, so there's no point inserting these.
I do hope to add trace points to pf at some point, but I'll create a new review then.