Check bgp_path.len without some AS

Xavier Trilla xavier.trilla at
Sun Jan 6 13:16:19 CET 2019

This is exactly what I've been trying to do, most probably I had something wrong with the syntax and that's why it was not working, I'll test it this week.


Saludos Cordiales,
Xavier Trilla P.<>

?Un Servidor Cloud con SSDs, redundado
y disponible en menos de 30 segundos?

?Pru?balo ahora en<>!

El 6 gen 2019, a les 1:30, Ondrej Zajicek <santiago at<mailto:santiago at>> va escriure:

On Thu, Jan 03, 2019 at 11:10:00PM +0000, Xavier Trilla wrote:

For some route selection configurations I need to check the bgp_path.len without some AS numbers.

I tried something like:


if bgp_path.len < N then ...

But doing this I modify permanently the AS path.

I've tried using a temp variable, but looks like bird doesn't allow to create bgppath "variables".


Although approach suggested by Alexander Zubkov is applicable,
i would note that BIRD allows bgppath variables, see:

filter testfilter
bgppath pp;
 pp = bgp_path;
 pp = prepend(pp, 65500);
 pp = prepend(pp, 65500);
 print pp, " ", pp.len;

The only think that is strange is that operators like delete or prepend
cannot be used with 'dot-syntax' (i.e. pp.prepend(X)), but must be used
with 'function-syntax' (i.e. pp = prepend(pp, X)).

Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at<mailto:santiago at>)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3,<>)
"To err is human -- to blame it on a computer is even more so."
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the Bird-users mailing list