October 2022 - Bird-users

[PATCH] Bus error on ARMv7 when using OSPF
by Matthew Reeve 18 Dec '24

18 Dec '24

Hi, when using bird 2.0.8 on openwrt 21.02 (and other versions) on a Netgear R7800 router, if the OSPF protocol is used, either v2 or v3, bird immediately crashes on startup with: Fri Jun 11 14:41:11 2021 daemon.info bird: Started Fri Jun 11 14:41:11 2021 kern.err kernel: [ 3500.853248] Alignment trap: not handling instruction f44c0a1f at [<00035848>] Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.853283] 8<--- cut here --- Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.859363] Unhandled fault: alignment exception (0x801) at 0x007e0624 Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.862443] pgd = 0bbef4fd Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.868821] [007e0624] *pgd=5d6ca835, *pte=5c40b75f, *ppte=5c40bc7f This router uses an ARMv7 processor and the issue seems to be to do with memory alignment issues. I've debugged it and traced it to an access to the top_hash_entry struct. I've found that if I add the PACKED macro to the struct definition then it fixes the problem, as per this patch: --- a/proto/ospf/topology.h +++ b/proto/ospf/topology.h @@ -41,7 +41,7 @@ struct top_hash_entry u8 mode; /* LSA generated during RT calculation (LSA_RTCALC or LSA_STALE)*/ u8 nhs_reuse; /* Whether nhs nodes can be reused during merging. See a note in rt.c:add_cand() */ -}; +} PACKED; /* Prevents ospf_hash_find() to ignore the entry, for p->lsrqh and p->lsrth */ Thanks.

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logging via udp
by Alexander Zubkov 13 Dec '23

13 Dec '23

Hello, Made some dirty patch for myself to allow bird to send logs via udp. But it may be useful not only for me, so posting it here. It could be useful when server experiencing high IO-load. As syslog and file operations in bird are blocking, it can be blocked on writing to it for indefinite time, which could lead to various problems like protocol timeouts. So udp logging comes in handy here. The tradeoff is that we can miss some logs if they are not processed in time. You can specify udp log destination like that: log udp [host IP|"hostname"] [port NUMBER|"portname"] ... By default it uses destination ip 127.0.0.1 and port 514. There are some constraints like not much error handling. And this destination replaces file destination, i.e. you can not use those simultaneously and it may leak descriptors and some memory probably if both are specified. It also makes a new socket every time configuration is reloaded even if there is no change in options, but this is not a great deal.

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BIRD show bgp summary for cli
by Roman Bulakh 14 Jun '23

14 Jun '23

Hi, we use BIRD in our environment, and it would be very nice to have some command like `show bgp summary` in juniper. This command show information about peer IP, peer AS, last update, prefixes received/best/exported and last state. Example: bird> show bgp summary Peer AS Last state change Prfx rcvd/best/export State X.X.X.X asXXXX 2021-01-27 6786/6785/109000 Established Y.Y.Y.Y asYYYY 2020-12-16 0/0/0 Passive BGP Error: Hold timer expired The are patch created for BIRD 1.3.4 and 1.3.6, but it would be good to have this in upstream software, without rebuilding and patching. as I understand it, no functionality should be affected by these changes, this is only a visual update for cli. Old patches describes at pages: https://marc.info/?l=bird-users&m=132155489919052&w=2 http://trubka.network.cz/pipermail/bird-users/attachments/20120228/a1499be7… https://bird-users.network.narkive.com/Px6EH3yl/bird-1-3-6-show-bgp-summary…

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Adding more then one bgp community at once
by Борис Коваленко 05 May '23

05 May '23

Hello! Is this possible to add many communites at once? bgp_community.add([(1,1), (1,2)]) is wrong "Setting clist attribute to non-clist value" Regards, Boris -- С уважением, Борис Коваленко

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Expiration for ROA tables until when the VRP is valid?
by Robert Scheck 07 Mar '23

07 Mar '23

Hello all, rpki-client recently implemented the "expires" instruction for roa-sets that OpenBGPD provides [1][2]. As of writing, BIRD does not seem to have something similar...any chance for it? From my understanding this only applies to included ROA files with VRP, not to RTR. [1] https://man.openbsd.org/bgpd.conf#roa-set [2] https://github.com/rpki-client/rpki-client-openbsd/commit/7bf63da6ec80f37bd… Kind regards Robert Scheck

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BIRD 2.0.{7,10} MED not actually send for learned routes if export table on is set
by Inrin 04 Feb '23

04 Feb '23

Greetings, I noticed during setting up a peering that the MED is not actually send to my peer, although bird shows it in the export. We confirmed this via tcpdump on both ends. After debugging a bit, I noticed that this only affects “learned” routes but routes from the static protocol worked just fine. After disabling the “export table” feature, the MED was send out just fine. Is this behaviour expected? This behaviour is reproducible in BIRD 2.0.7 and 2.0.10 with the following scenario (Configs to test are attached): R0 is connected to R1 and R2 R0, R1 and R2 send each one route R0 sets the MED to 300 R1 sets the MED to 100 R2 sets the MED to 200 Setting “export table on;” yields the following results: # Bird shows the MED in the export R0 $ ./birdc s r all export R1 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [static1 02:05:56.604] * (200) Type: static univ BGP.med: 300 198.18.2.0/24 unicast [R2 02:11:51.132 from 198.19.0.2] * (100) [AS4242420002i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420002 BGP.next_hop: 198.19.0.2 BGP.med: 300 BGP.local_pref: 100 R0 $ ./birdc s r all export R2 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [static1 02:05:56.604] * (200) Type: static univ BGP.med: 300 198.18.1.0/24 unicast [R1 02:11:51.133 from 198.19.0.1] * (100) [AS4242420001i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420001 BGP.next_hop: 198.19.0.1 BGP.med: 300 BGP.local_pref: 100 R0 # But on R1, R2 it does not appear for learned routes: R1 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 02:11:51.133 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.2.0/24 unicast [R0 02:11:51.133 from 198.19.0.0] * (100) [AS4242420002i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420002 BGP.next_hop: 198.19.0.0 BGP.local_pref: 100 R1 $ R2 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 02:11:51.132 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.1.0/24 unicast [R0 02:11:51.133 from 198.19.0.0] * (100) [AS4242420001i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420001 BGP.next_hop: 198.19.0.0 BGP.local_pref: 100 R2 $ Setting “export table off;” yield the expected result: R1 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 03:15:47.147 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.2.0/24 unicast [R0 03:15:50.635 from 198.19.0.0] * (100) [AS4242420002i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420002 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 R1 $ R2 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 03:15:50.635 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.1.0/24 unicast [R0 03:15:50.635 from 198.19.0.0] * (100) [AS4242420001i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420001 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 R2 $

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[PATCH] feature to keep protocol's state while configuring
by Alexander Zubkov 29 Jan '23

29 Jan '23

Hello. I have created a patch (attached) with new protocol option: disabled keep on|off. To keep the protocol's state while loading new config. It is useful when protocols disabled manually in the runtime, but we want to keep that state when loading new config. Patch is attached. I have made it against the current int-new branch.

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Debugging advertised prefixes that are seemingly never seen by BIRD
by Andy Smith 03 Nov '22

03 Nov '22

Hi, On BIRD 2.0.7 I've got some eBGP sessions with this config: # bird.conf filter bgp6_out { if (source = RTS_INHERIT) && (net ~ [ 2001:DB8:1F1::/48+ ]) then accept; else reject; } protocol kernel { ipv6 { import all; export filter { krt_prefsrc = 2001:DB8:0:1f1::e; accept; }; }; metric 500; learn; scan time 10; merge paths on; } protocol bgp uplinka6 { local 2001:db8::64:607a as 64607; neighbor 2001:db8::64:607b as 64943; hold time 30; ttl security on; ipv6 { import all; export filter bgp6_out; }; } # END The session establishes and 2001:db8::64:607b sends me some 591 IPv6 prefixes, however only 385 of them end up in my routing table, without any logging as to why. I've done "debug uplinka6 all" and then "restart uplinka6" and there is no mention in the logs at all of any of the missing prefixes yet I can see them in a tcpdump so I know 2001:db8::64:607b is sending. Also the operator of 2001:db::64:607b is convinced they are being advertised correctly. Watching "ip monitor route" I also see no mention at all of the prefixes I'm not getting. Is there any kind of enhanced debugging I can do to work out why BIRD does not do anything with some of those prefixes? The only suspicious thing in my syslog is: Oct 29 21:21:09 hostname bird: Restarting protocol uplinka6 Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute Oct 29 21:21:13 hostname bird: uplinka6: Invalid NEXT_HOP attribute However, even though I don't know which prefixes these are related to, they do only happen 11 times (every time), not 100+ times as I would expect if that were the culprit. Still, if there is a way to get more information about which prefix/nexthop it doesn't like here, that would also be good. An example from tcpdump that was running while "restart uplinka6" was happening: 20:06:20.516521 IP6 (class 0xc0, hlim 255, next-header TCP (6) payload length: 1460) 2001: db8::64:607b.179 > 2001:db8::64:607a.44737: Flags [.], cksum 0x79e5 (correct), seq 4777:62 17, ack 188, win 16197, length 1440: BGP Update Message (2), length: 621 Multi-Protocol Reach NLRI (14), length: 574, Flags [OE]: AFI: IPv6 (2), SAFI: Unicast (1) nexthop: 2001:db8::64:608a, nh-length: 16, no SNPA 2001:db8:1f1:200::/56 2001:db8:1f1:d00::/56 2001:db8:1f1:e00::/56 2001:db8:1f1:1900::/56 2001:db8:1f1:f003::/64 2001:db8:1f1:f007::/64 2001:db8:1f1:f00d::/64 2001:db8:1f1:f012::/64 2001:db8:1f1:f01a::/64 2001:db8:1f1:f023::/64 2001:db8:1f1:f038::/64 2001:db8:1f1:f03a::/64 2001:db8:1f1:f03b::/64 2001:db8:1f1:f042::/64 2001:db8:1f1:f048::/64 2001:db8:1f1:f052::/64 2001:db8:1f1:f059::/64 2001:db8:1f1:f06d::/64 2001:db8:1f1:f06e::/64 2001:db8:1f1:f07c::/64 2001:db8:1f1:f0b4::/64 2001:db8:1f1:f0bc::/64 2001:db8:1f1:f0c3::/64 2001:db8:1f1:f0c5::/64 2001:db8:1f1:f0e8::/64 2001:db8:1f1:f0ea::/64 2001:db8:1f1:f10d::/64 2001:db8:1f1:f11c::/64 2001:db8:1f1:f120::/64 2001:db8:1f1:f123::/64 2001:db8:1f1:f12b::/64 2001:db8:1f1:f142::/64 2001:db8:1f1:f142::/64 2001:db8:1f1:f143::/64 2001:db8:1f1:f153::/64 2001:db8:1f1:f155::/64 2001:db8:1f1:f15f::/64 2001:db8:1f1:f164::/64 2001:db8:1f1:f191::/64 2001:db8:1f1:f199::/64 2001:db8:1f1:f1ab::/64 2001:db8:1f1:f1e6::/64 2001:db8:1f1:f1f4::/64 2001:db8:1f1:f22e::/64 2001:db8:1f1:f24f::/64 2001:db8:1f1:f2e0::/64 2001:db8:1f1:f309::/64 2001:db8:1f1:f334::/64 2001:db8:1f1:f342::/64 2001:db8:1f1:f350::/64 2001:db8:1f1:f361::/64 2001:db8:1f1:f36c::/64 2001:db8:1f1:f371::/64 2001:db8:1f1:f376::/64 2001:db8:1f1:f384::/64 2001:db8:1f1:f38c::/64 2001:db8:1f1:f057::/64 2001:db8:1f1:f03e::/64 2001:db8:1f1:f0fc::/64 2001:db8:1f1:f1d1::/64 2001:db8:1f1:c00::/56 2001:db8:1f1:f060::/64 2001:db8:1f1:f09d::/64 Origin (1), length: 1, Flags [T]: IGP AS Path (2), length: 6, Flags [T]: 64943 Multi Exit Discriminator (4), length: 4, Flags [O]: 0 None of those made it into my kernel routing table or were logged by BIRD's debug at all. All of those have nexthop 2001:db8::64:608a that being another of my servers, so to experiment I tried adding a route like BIRD would: # ip route add 2001:db8:1f1:c00::/56 via 2001:db8::64:608a metric 500 and did get: RTNETLINK answers: No route to host which is odd because there is a route that was accepted for this nexthop: $ ip route get 2001:baf::64:608a 2001:db8::64:608a from :: via 2001:db8::64:607b dev bond0 proto bird src 2001:db8:0:1f1::e metric 500 pref medium and I can ping it. There are routes like the above for all of the 2001:db8::64:6xxa that are my servers. $ ip -6 ro | grep ^2001:db8::64:6..a/127 2001:db8::64:601a/127 via 2001:db8::64:607b dev bond0 proto bird src 2001:db8:0:1f1::e metric 500 pref medium 2001:db8::64:602a/127 via 2001:db8::64:607b dev bond0 proto bird src 2001:db8:0:1f1::e metric 500 pref medium …etc Any ideas? Thanks, Andy

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Experimental MPLS L3VPN code
by Ondrej Zajicek 18 Oct '22

18 Oct '22

Hello Recently i made some experimental MPLS code for BIRD, which includes MPLS label manager, MPLS support for static and BGP protocols and also L3VPN protocol. It can be used for L3VPN PE routers with MPLS backplane, with BGP used for label distribution. It has some rough edges and not ready for merging, but if anyone is interested, see branch mpls: https://gitlab.nic.cz/labs/bird/-/commits/mpls There are not much documentation outside of this commented example of PE router config: https://gitlab.nic.cz/labs/bird-tools/-/blob/master/netlab/cf-mpls-bgp-l3vp… Comments or questions are welcome. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santiago(a)crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."

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Projects using Bird as routing engine
by Douglas Fischer 18 Oct '22

18 Oct '22

I don't know if such a thing already exists... But I thought it would be interesting to have some kind of survey of projects that use BIRD at some point in their structure. I know for example that http://projectcalico.org/ uses BIRD as a routing engine. Or that https://bsdrp.net/ has the possibility to use FRR or BIRD as a routing engine. I think it's worth mentioning that Bird has a presence in route-collectors projects... But which ones? Where? In IXP? Well... This is BIRD land. I think we can estimate that more than 80% of IXPs use BIRD as the Route-Servers engine. I remember seeing a place that said which route-servers from which IXPs ran with which BGP engine. But I couldn't find that link easily. But still within the scope of IXPs and Route-Servers, there are projects like https://www.ixpmanager.org/ based on the framework it provides to those who adopt it. As well as BIRD appears to be the main choose engine at https://github.com/pierky/arouteserver . Is it worth mentioning BIRD being used by Netflix in Open Connect Appliances? I remember recently seeing a project for an Internet Transit Provider system, but I don't remember the name of the blessed project. Does anyone else remember anything else that uses BIRD? Would it be interesting to put this information on some public page? -- Douglas Fernando Fischer Engº de Controle e Automação

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