IPFW: more "orthogonal? state operations, push into 11?

[Bill Yuan]

In my opinion,

keep-state == "if this kind of packet come again, we are going to perform
the current action"
check-state == "did we met this kind of packet before? Yes! then perform
that action"

so in DragonflyBSD, below commands are implemented to manipulate the
"states"

     ipfw3 state show [rulenum]
     ipfw3 state add rule rulenum proto src:port dst:port [state-options]
     ipfw3 state delete rulenum


On 8 June 2016 at 18:36, Andrey V. Elsukov <ae at freebsd.org> wrote:

> On 07.06.16 17:31, Ian Smith wrote:
> > If your patch does what Lev wanted to achieve with (I thought too many)
> > new dynamic rule actions, then I think your simpler solution is better,
> > not least because it's far easier to understand for non-Julians :)
> >
> > Looking from a useability and documentation perspective only - I won't
> > even be looking at this code - I have a few thoughts:
> >
> > Thus far, keep-state and limit seem to be interchangeable options; limit
> > rules will need to work the same with respect to named dynamic flows; do
> > I assume that you've just started with only keep-state for testing?
>
> We don't use limit rules at all, so it wasn't implemented. I think it
> will not so hard to implement.
>
> > I think flow names should be specified as an _optional_ parameter, thus:
> >
> >     check-state [name]
> >
> >     keep-state [name]
> >
> >     limit {src-addr | src-port | dst-addr | dst-port} N [name]
> >
> > where name (maybe flowname, for easier comprehension by man readers?) is
> > optional, assigned as 'default' whenever omitted - as well as being for
> > backwards ruleset compatibility, which then only needs mentioning once,
> > and maybe also put another way in the STATEFUL FIREWALL section.
> >
> > So a few of the existing example rules with no name could stand, while
> > others (see below) append names of OUTBOUND and INBOUND or whatever.
> >
> > As is, you have
> >
> > 740           .It Cm check-state Op Ar name | Cm any | Cm default
> >
> > which in other contexts would mean you have to supply one of 'name' or
> > 'any' or 'default' when you don't have to provide one, 'default' being
> > assigned otherwise.  Otherwise I think this is fairly well described.
> >
> > Will 'ipfw -[e]d list|show' show the flow names? or the indices?
>
> It will show the flow name at the end of line.
>
> > As I pestered Lev about last year, we still need a small example ruleset
> > section that actually deals with potentially problematic stateful issues
> > with NAT - which I still don't fully understand - beyond descriptions in
> > the abstract case; ie an actual working dual- or multi-flow example.
> >
> > I know these are "just doc" issues of little importance while testing
> > working code, and I haven't supplied any patches, so are just FWIW ..
>
> Will try to implement support for limit rules and update man. Thanks.
>
> --
> WBR, Andrey V. Elsukov
>
>