March 2024 - Bird-users - Mailing Lists

Problem with uplink network announcment in IPv6
by Yasen Atanasov 02 Apr '24

02 Apr '24

Hello, I've experienced a strange problem when implementing IPv6 connectivity. My ISP gave me /126 for connection between bgp routers and uplink connectivity. A lot of(but not all) routes couldn't be inserted in the kernel. After some experimentation we realized that administrative route that is created buy the kernel for local networks was overridden by the bird and after that no new routes were inserted in the kernel table. ~# ip r get x::y x::y from :: via x::y dev eth6 proto bird src x::z metric 32 pref medium vs x::y from :: dev eth6 proto kernel src x::z metric 256 pref medium Where x::y is uplink BGP peer and x::z our BGP router. Filtering /126 network from imports resolved the problem Is this normal behavior for Bird or some misconfiguration from our side? Should I report that as misconfiguration to my ISP? I'm using bid 2.0.12 from Devuan 5 repos. Any input will appreciated. Yasen

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Coexistence of multiple babel daemons on the same host
by Daniel Gröber 02 Apr '24

02 Apr '24

Hi Babelers, I've just come across a reason I'd want to run babel with both bird and babeld on the same node and have them become neighbours. The details are tedious -- my usual disclamer applies ;) This got me to think about something I'd observed in the past and been meaning to write about though: when I accidentally had both babeld and bird running on a node it would casuse severe route flapping and consequently packet loss. I wonder if we can do better here? Maybe by warning about this situation in the logs, shutting down both sides or just turning this into a supported use-case? :) >From what I gather by a quick skimming of the relevant details in RFC8966 this could work by assigning each daemon a unique LL address so each gets it's own entry in the neighbour table, right? Thanks, --Daniel

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How to make bird and freebsd carp working together ?
by Arnaud Houdelette-Langlois 01 Apr '24

01 Apr '24

Hi I got two routers running freebsd (BSDRP). Those two are used as redundant site firewalls and main routers / route servers. Both exchange routes between themselves and other routers using Bird (OSPF+BGP). Both serve as gateway for our management network, with carp enabled. I got trouble making CARP and BIRD working together. The carp enabled interface use a dummy network for exchanging carp info (link local adresses : 169.254.1.0/24) Bird Device protocol does not makes any difference between adresses in MASTER or BACKUP vhids, so the route appears in both routers. I tried with recent "learn all" feature of kernel protocol : There, bird only picks up route when its master, but, in case of MASTER failover or preemption, it doesn't remove the route early enough, and freebsd does not seem to replace the route on it’s kernel table, so when birds finally removes the route, we end up with no route at all. (and a non working network segment). Am I the only one facing this issue ? Is there a way to make bird carp aware ? Thanks -- Arnaud Houdelette-Langlois Administrateur des infrastructures systèmes et réseaux Normandie Université

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Babel and Unnumbered interfaces
by Pim van Pelt 30 Mar '24

30 Mar '24

Hoi folks, By means of context, I am working on allowing VPP and Bird2/Babel to program the routing table with IPv6 nexthops for IPv4 destinations. I finished a few small code changes in VPP to allow transit-net-less transport of IPv4 and IPv6 in VPP and wrote about it on https://ipng.ch/s/articles/2024/03/06/vpp-babel-1.html <https://ipng.ch/s/articles/2024/03/06/vpp-babel-1.html>. Considering this dataplane has some different idioms than Linux, it took a bit of work. I thought you might find this VPP + Bird2 + Babel story from the field interesting. I wanted to ask you to read the article, and in particular the /Additional thoughts/ section at the bottom, as it tries to ask for opinions on a somewhat complex topic of unnumbered point-to-point interfaces in VPP. On the VPP side, I have a small change (https://gerrit.fd.io/r/c/vpp/+/40482) that builds support for point-to-point over Ethernet. With this approach, VPP will copy the IPv4 and IPv6 address over from a loopback interface to the ethernet transit networks. In the article above, I mentioned in /Approach 3/, One option is to ask Babel to use |extended next hop| even when IPv4 is available, which would be a change to Bird (and possibly a violation of the Babel specification, I should read up on that). I don't think it's a violation of the Babel protocol to use IPv6 next hops when an IPv4 address is present. However, I noticed that in proto/babel/babel.c function babel_send_update_() the protocol /always/ prefers IPv4 when it's set. My question: would it be feasible to extend the configuration syntax of /extended next hop/ to also allow keyword /always/, in which case the IPv6 nexthop is preferred even if an IPv4 address is present? The logic in proto/babel/babel.c 1039-1950 seems straight-forward to adapt to this case, in a non-intrusive way. I can attempt a patch if the Bird (and Babel) community believes this is a useful behavior. groet, Pim -- Pim van Pelt PBVP1-RIPE -https://ipng.ch/

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Failover BGP servers?
by Yasen Atanasov 29 Mar '24

29 Mar '24

Hello, Lets imagine I have 2 BGP servers announcing same subnet. BGP sessions with upstream are in different VLAN. Both servers have keepalived and all clients are using for default route the virtual address. The idea is if I need to upgrade/rebuild one of the servers the clients will still have connectivity trough the other server. Do I need to do something special in the bird config or just announcing the same net is enough? Regards. Yasen

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Suggestion : Add protocol default preferences to documentation.
by Arnaud HOUDELETTE-LANGLOIS 26 Mar '24

26 Mar '24

Hi I could not found default protocol preferences on the user doc. I had to search the code. I think the defaults (or at least the order of preference) should be somewhere in the documentation. This is the info I was looking for : /* * Default protocol preferences */ #define DEF_PREF_DIRECT 240 /* Directly connected */ #define DEF_PREF_STATIC 200 /* Static route */ #define DEF_PREF_OSPF 150 /* OSPF intra-area, inter-area and type 1 external routes */ #define DEF_PREF_BABEL 130 /* Babel */ #define DEF_PREF_RIP 120 /* RIP */ #define DEF_PREF_BGP 100 /* BGP */ #define DEF_PREF_RPKI 100 /* RPKI */ #define DEF_PREF_L3VPN_IMPORT 80 /* L3VPN import -> lower than BGP */ #define DEF_PREF_L3VPN_EXPORT 120 /* L3VPN export -> higher than BGP */ #define DEF_PREF_INHERITED 10 /* Routes inherited from other routing daemons */ Thanks to the devs for the good work. -- Arnaud HOUDELETTE-LANGLOIS Administrateur systèmes et réseaux informatiques Responsable de la sécurité des systèmes d'information Normandie-Université +33 2 31 56 69 54

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2.15, ospf is broken
by Dmitry Melekhov 26 Mar '24

26 Mar '24

Hello! Just upgraded and got: Mar 19 08:07:46 hohr-vpn-1 bird[1523831]: Started Mar 19 08:07:54 hohr-vpn-1 bird[1523831]: MyOSPF: Unexpected case in next hop calculation Mar 19 08:07:54 hohr-vpn-1 bird[1523831]: MyOSPF: Cannot find next hop for LSA (Type: 2002, Id: 192.168.222.221, Rt: 192.168.22.178) Mar 19 08:07:54 hohr-vpn-1 bird[1523831]: MyOSPF: Unexpected case in next hop calculation etc. on all hosts I upgraded. All of them is alma 9. Downgrade to 2.14 solved problem. Is there fix for this or workaround? Thank you!

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Export shows new filters after "configure soft" before any update
by Inrin 25 Mar '24

25 Mar '24

Hiho, I noticed that `birdc show route export <proto>` after a `configure soft` shows the state with the new export filter, even if no update ocurred. The PCAP also shows, as long as no external update comes in, no updates are send out on the wire. Using export tables makes it possible to see the "real" state. For example, until a new external update or a `reload out` it shows the "old filter" state. For import filters it's different. It shows the "old" state until an external update comes in or `reload in` is used. With or without import tables or `keep filtered on`. Since the help states: configure soft ["<file>"] [timeout [<sec>]] Reload configuration and ignore changes in filters it should be like for the import case and show the "old" state until an update comes in or `reload out` is used. Finally to my question: Is this behaviour intentional? Best would be to even make it possible to ignore the new filters until manual reload, but thats probably a bigger change ;) For testing I used 2 exabgp clients and BIRD as intermediate. Configs are attached below. The large community had been just increased to trigger changes. Thanks, Inrin ================================================================= BIRD config ----------------------------------------------------------------- debug protocols all; debug channels all; log syslog all; protocol device { } protocol direct { disabled; ipv4; ipv6; } protocol kernel { disabled; ipv4; } protocol kernel { disabled; ipv6; } template bgp clients { local as 64500; ipv4 { #import table on; #export table on; #import keep filtered on; import none; export none; }; ipv6 { import none; export none; }; } protocol bgp sender4 from clients { neighbor 198.51.100.3 as 64503; ipv4 { import filter { accept; }; export none; }; } protocol bgp receiver4 from clients { neighbor 198.51.100.4 as 64504; ipv4 { import none; export filter { bgp_large_community.add((7,7,7)); accept; }; }; } ----------------------------------------------------------------- Exabgp config sender ----------------------------------------------------------------- template { neighbor rsipv4 { local-address 198.51.100.3; local-as 64503; peer-as 64500; family { ipv4 unicast; } announce { ipv4 { unicast 192.0.2.0/24 next-hop self large-community [64503:4444:0]; } } } } neighbor 198.51.100.251 { inherit rsipv4; } ----------------------------------------------------------------- Exabgp config sender ----------------------------------------------------------------- template { neighbor rsipv4 { local-as 64504; peer-as 64500; local-address 198.51.100.4; family { ipv4 unicast; } } } neighbor 198.51.100.251 { inherit rsipv4; } -----------------------------------------------------------------

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[2.14] show route not showing all tables (rpki)
by Elmar K. Bins 22 Mar '24

22 Mar '24

Hello folks, we're running 2.14 on FreeBSD 13.3 (out of the current bird2-2.14 pkg). A long time ago we set up RPKI feeds that put their routes into tables r4 and r6. I've just added a second RPKI source that feeds into table r44 and r66. "show route count" does NOT include these tables: --------------- bird> show route count 25524 of 25524 routes for 14191 networks in table master4 2775 of 2775 routes for 1808 networks in table master6 421637 of 421637 routes for 421637 networks in table r4 101571 of 101571 routes for 101571 networks in table r6 Total: 551507 of 551507 routes for 539207 networks in 4 tables bird> show route table r44 count 401463 of 401463 routes for 401463 networks in table r44 bird> shor route table r66 count No such command. Press `?' for help. --------------- (yeeees, birdc has been fully restarted, just in case something was hanging). Any idea why? Is this intentional, an oversight, or a bug? I'd like all my tables to show please. Elmar.

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BIRD 2.15.1
by Ondrej Filip 22 Mar '24

22 Mar '24

Dear BIRD users, we're releasing a new version 2.15.1. As the number suggests, it is a bug fixing release: Version 2.15.1 o OSPF: Fix regression in handling PtP links o RPKI: Handle connection resets properly o Static: Reject invalid combination of options o Fix builds with limited set of protocols Happy routing! Ondrej

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