How can I set krt_realm in the kernel protocol by gw (nexthop) value?

[Eric Wheeler]

On Fri, 30 Jul 2021, Alexander Zubkov wrote:
> You have to update krt_realm attribute in your filter, like that:
> 
> function gw_realms() {
>         if gw = 1.1.1.1 then return 1;
>         if gw = 2.2.2.2 then return 2;
>         if gw = 3.3.3.3 then return 3;
>         return 0;
> }
> 
> filter peer_realms {
>         krt_realm = gw_realms();
>         accept;
> }
> 
> protocol kernel kernel_ipv4 {
>     ipv4 {
>         export filter peer_realms;
>     };
> }


Thank you, that worked great.  Do you know who might add your example to 
the documentation?

--
Eric Wheeler


> 
> On Fri, Jul 30, 2021 at 6:05 AM Eric Wheeler <bird at lists.ewheeler.net> wrote:
> >
> > Hello all,
> >
> > I would like to put routes in realms for traffic accounting based on the
> > peer IP provided by a BGP route server on an exchange.  I was thinking I
> > could do something like this, but bird gives errors like "syntax error,
> > unexpected KRT_REALM":
> >
> >         filter gw_realms {
> >                 if gw = 1.1.1.1 then return 1;
> >                 if gw = 2.2.2.2 then return 2;
> >                 if gw = 3.3.3.3 then return 3;
> >                 return 0;
> >         }
> >
> >         protocol kernel kernel_ipv4 {
> >             ipv4 {
> >                 krt_realm filter peer_realms;
> >             };
> >         }
> >
> >
> > What is a proper way to dynamically set the krt_realm attribute per gw?
> >
> > Thank you for your help!
> >
> > --
> > Eric Wheeler
>