On 10/05/2023 19:46, Maria Matejka via Bird-users wrote:
Hello!
Thanks for replying.
On 5/10/23 11:13, William wrote:
Hi All,
I've been digging around trying to find a nice way of doing it but
can't seem to find a valid answer.
Is there a way to use a prefix set to create static routes?
No, this is not possible and implementing this would be surprisingly
difficult as the prefix sets are implemented as a compressed trie
optimized for fast lookup and not enumeration.
Also imagine this:
define my_route_set = [ 2001:db8/32+ ]; # note the plus sign
protocol static { ipv6; route my_route_set via 2001:db8::dead:beef; }
This short code would generate approx. 7.9e28 routes.
Yeah, that could hurt.
If you could elaborate more precisely what you are trying to achieve
as a whole result, we may try to help you find how to do it in the way
BIRD is designed.
We have a number of remote sites where there are non-dynamically routed
downstream subnets that we need to add as static routes (anything from 1
to 20+ per site) but also advertise upstream back into the WAN.
Instead of specifying each prefix as an individual static route I was
hoping to be able to use the existing prefix set to act as a list of
routes to add. If there was a way to iterate over the set in a loop
fashion then that would suffice. In our instance there aren't modifiers
on the masks (no -'s, +'s or {minlen, maxlen}) hence the idea of being
able to use the set as "just a list" - this could be a condition of
using it for that function.
For example (twist on my original):
define my_route_set = [ 10.1.2.3/24, 172.20.4.2/24, 10.200.0.0/23 ];
protocol static route_set {
ipv4 {
table Some_Routes;
}
for ThisRoute in my_route_set {
route ThisRoute via 192.168.55.2; # downstream static gateway
}
route 5.6.7.8/32 via 192.168.55.1;
}
Resulting in:
bird> sh route table Some_Routes
Table Some_Routes:
10.1.2.3/24 unicast [route_set 2023-05-10] * (200)
via 192.168.55.2 on ens256
10.20.4.2/24 unicast [route_set 2023-05-10] * (200)
via 192.168.55.2 on ens256
10.200.0.0/23 unicast [route_set 2023-05-10] * (200)
via 192.168.55.2 on ens256
5.6.7.8/32 unicast [route_set 2023-05-10] * (200)
via 192.168.55.1 on ens256
192.168.55.0/24 unicast [Local_Ints 2023-05-10] * (240)
dev ens256
bird>
Hope that explains better what I'm hoping to achieve. I couldn't see a
way of doing it with if..then..else or case statements. The only other
option would be to have a script scrape the set out of the config and
prepare an include file *shudder*.
Regards,
William
