Hi all,
For the record, I've written a little bash tidbit that works for the
moment, just means a lot of route statements in the static protocol in
worst cases:
NEWGW="172.24.16.2"; grep "define site_subnets" bird.conf | sed -e
's/^.*\[ / route /' -e "s/ \].*$/ via $NEWGW;\r/" -e "s/, / via
$NEWGW;\r route /g"
It includes a little indentation too, adjust for your nesting spacing
scheme. It picks up on the set named "site_subnets", breaks it apart
and creates unix-terminated (CR, no LF) lines for each prefix listed.
Hasn't been tested on IPv6 prefixes though, but I suspect it will Just
Work(tm).
Regards,
William
On 13/05/2023 21:51, William wrote:
On 13/05/2023 4:12 pm, Ross Tajvar wrote:
What are you using the prefix set for in the first place?
In this particular case it is used to filter inbound and restrict
outbound advertisements with upstream BGP routers to ensure that site
doesn't receive its own routes back, but also protect the rest of the
network from accidentally advertising the wrong routes (like default
route).
In some situations the routes may be directly connected (and so fed
into the route tables by direct protocol entries), others via
downstream hosts like I mentioned and that point we need to add the
routes one-by-one into the tables.
On Thu, May 11, 2023, 2:34 AM William <[email protected]>
wrote:
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 [1], 172.20.4.2/24 [2],
10.200.0.0/23 [3] ];
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 [4] via 192.168.55.1;
}
Resulting in:
bird> sh route table Some_Routes
Table Some_Routes:
10.1.2.3/24 [1] unicast [route_set 2023-05-10] * (200)
via 192.168.55.2 on ens256
10.20.4.2/24 [5] unicast [route_set 2023-05-10] * (200)
via 192.168.55.2 on ens256
10.200.0.0/23 [3] unicast [route_set 2023-05-10] * (200)
via 192.168.55.2 on ens256
5.6.7.8/32 [4] unicast [route_set 2023-05-10] * (200)
via 192.168.55.1 on ens256
192.168.55.0/24 [6] 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
