constant for empty prefix set

[Ondrej Zajicek]

On Thu, Feb 10, 2022 at 02:09:59PM +0100, Alexander Zubkov wrote:
> Hi,
> 
> Let me remind about this once again.

Hi

Sorry for ignoring your previous mail, i needed to focus on finishing
things for 2.0.9, now i can continue with your patches.

1) UDP logging - I have no principal issue with this, will review and merge.

2) Keeping proto state during reconfiguration - I am ok with 'configure keep'
patch, will preview and merge. I do not want 'keep state' per-protocol
option. Perhaps also some 'configure xyz' for regular configure and some
global option how 'configure' without arguments should behave for people
who would like 'configure keep' to be the default behavior.

3) prepend_times() - I am a bit ambivalent about that. I see usefulness
of that. I do not like the name. It can be implemented as optional
argument to prepend(), but not sure if that is better. Will think about
that. Also, considering user mistakes like [*], we perhaps should
limit multiplier by say 16.

[*] https://bgpmon.net/long-as-paths-causing-commotion/

4) Empty prefix set - Too hacky and inconsistent syntax. Note that there
are also non-prefix sets. We already have ugly hacks for empty community
lists, we want to avoid yet another way to define empty structures.

Unfortunately there is no easy way to define literals that could be used
for multiple data types. We already have A.B.C.D, that could be both IP
address and router ID, and it is super annoying in the code. We would
like to have some more generic solution, we will think about that.

5) Reduce/reduce fix - Will look at this.


> On Tue, Jan 11, 2022 at 1:10 PM Alexander Zubkov <green at qrator.net> wrote:
> >
> > Hi,
> >
> > Let me ping this. I would like to receive a feedback on this (and some
> > other my recent) messages.
> >
> > On Sat, Jan 1, 2022 at 9:45 PM Alexander Zubkov <green at qrator.net> wrote:
> > >
> > > Hi,
> > >
> > > I propose to add some constant for empty prefix set, for example (as
> > > in the patch):
> > > define pfx_empty = [ /empty/ ];
> > >
> > > It is useful when we define a named prefix list, which we can use
> > > somewhere in filters, but this prefix list is generated, for example,
> > > and we may need to make it empty. But there is no currently means to
> > > create an empty prefix set, as I understand.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."