April 2026 - Bird-users - Mailing Lists

Extracting octets/quads from IP addresses in filter expressions
by Stefan Pisjak 08 Apr '26

08 Apr '26

Hi fellow bird users! I've searched through the documentation/this mailing list, but I haven't found anyone trying to build a similar filter so far. I'm trying to build a filter to only allow BGP routes if the "host part" of `ip from` matches the route that is being announced, e.g.: 10.0.1.2 is allowed to announce 10.100.1.2/32 10.0.1.3 is allowed to announce 10.100.1.3/32 [...] 10.0.X.Y is allowed to announce 10.100.X.Y/32 But as far as I can tell, it's not possible to somehow convert the type ip to type quad or something like that. Is there a better way to build this filter, or can you somehow create a new variable of the type ip and modify it or convert the ip to a quad and then do the manipulations? Kind regards, Stefan DISCLAIMER: This communication may contain confidential and privileged material for the sole use of the intended recipient. Any unauthorized review, use or distribution by others is strictly prohibited. If you have received the message by mistake, please advise the sender by reply email and delete the message. Thank you.

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BMP in 2.18.1
by Srdjan Markovic 07 Apr '26

07 Apr '26

Hi! Bird2 fails to start after upgrade to 2.18.1 with the following error message: /etc/bird/bird.conf.d/bird-pmacctd.conf:1:10 syntax error, unexpected CF_SYM_UNDEFINED Content of the file is: protocol bmp pmacctd { station address ip 127.0.0.1 port 17917; monitoring rib in pre_policy; monitoring rib in post_policy; tx buffer limit 64; } Downgrading back to 2.18 (apt-get install bird2=2.18-cznic.1~trixie), without touching the config, lets bird2 start again. I can't find the build log in Gitlab to check if the configure option was omitted, nor anything in the NEWS file. Kind regards, Srdjan

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Reconfiguring MPLS channel while down causes segfault on bird 3.2.0
by Max Hearnden 07 Apr '26

07 Apr '26

Hello, I've found an issue with bird 3.2.0 which can be reproduced with the following configuration (no peer required). Just run configure after starting bird. router id 1; mpls table mtab; mpls domain mdom; protocol bgp test { local 192.0.2.2 port 8179 as 65000; neighbor 192.0.2.1 as 65001; mpls {label policy aggregate;}; } It appears that this issue is caused because c->mpls_map is only set in mpls_channel_start instead of mpls_channel_init which would also match the deallocation in mpls_channel_cleanup. This means that before the channel is first up c->mpls_map is null and would cause a null pointer dereference as part of mpls_fec_map_reconfigure (called in mpls_channel_reconfigure).

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BGP reload routes issue
by Derco Sportel 02 Apr '26

02 Apr '26

Hello, We've been relying on bird heavily in our DC and basically all of our servers use bird. All server advertise /32 addresses using BGP toward the network and we use BFD for fast-fail. Lately we have observed some issues with bird reloads where some neighbors report reload failed. After investigation it looks as if the reload fails if the following conditions have been met: 1. BGP sessions were established 2. BGP flapped for $reason (router reload, BFD flap, other) After this, even though the BGP sessions are there, the Route refresh capability is no longer possible. A restart of bird solves the problem. After investigation we suspect this is caused by the combination of these parts of the code: https://github.com/CZ-NIC/bird/blob/9d509f232eaf04f707f51fd2368841d899ab8af… and https://github.com/CZ-NIC/bird/blob/9d509f232eaf04f707f51fd2368841d899ab8af… Our current install is version 3.2.0, though we have also observed route refresh issues with prior 3.x versions. The bgp_init creates the object with reload routes, but a bgp_stop makes it NULL. A bgp_start just starts the BGP session, but as the reload_routes is NULL we loose the Route refresh capability. We might be completely off track here, and this might very well be intended behavior, though we do suspect this to be wrong. Can someone have a look at this and tell us if this is a bug or a feature? Regards, Derco Sportel | System Engineer Networking | https://bol.com<https://bol.com/>

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