October 2021 - 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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[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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IGP Metric to MED
by Corban Johnson 29 Apr '22

29 Apr '22

Hello, I am trying to set MED on a BGP route using the metric value from OSPF, but the attributes of the next-hop route do not seem to be available in filter evolution. Am I missing something? Example Bird 2.0 config: protocol bgp test_peer { bfd on; med metric on; graceful restart on; ipv4 { table test_table; gateway recursive; }; local as 65656; } protocol ospf t1_igp { ipv4 { table test_table; }; } OSPF is distributing loopbacks and link nets only. BGP protocols from ‘test_peer’ will use routes learned from ‘t1_igp’ in ‘test_table’ to resolve next hop information (gateway recursive). So far, so good. However, I also have an eBGP peer (i.e. who is not participating in my IGP above) who is multi homed with AS65656. I would like to use MED to inform the peer about my IGP distances to each exit — something like the ‘metric-out minimum-igp <offset>’ command in Junos (https://www.juniper.net/documentation/en_US/junos/topics/reference/configur…) > You can increase or decrease the variable metric calculated from the IGP metric (either from the igp or minimum-igp statement) by specifying a value for offset. The metric is increased by specifying a positive value for offset, and decreased by specifying a negative value for offset. The problem seems to be that filters may only access attributes of the route currently processed, and the 'gateway recursive’ channel directive only calculates next-hop without passing any route attributes of that next-hop through. Has anyone had any luck trying something similar? Many thanks.

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Route export problem with FreeBSD 13.0
by Luiz Amaral 31 Mar '22

31 Mar '22

Hello guys, After upgrading one of my hosts from FreeBSD 12.2 to FreeBSD 13.0, I started noticing a problem when exporting routes to the KRT. My logs were getting flooded with "kernel: gw sdl_len too small". This message comes from cleanup_xaddrs_gateway() in sys/net/rtsock.c of releng/13.0, so I checked with "route monitor" and noticed that the blackhole routes and one interface route were the ones causing the message. got message of size 192 on Sat Aug 28 15:57:32 2021 RTM_ADD: Add Route: len 192, pid: 2293, seq 3, errno 22, flags:<UP,BLACKHOLE,PROTO1> locks: inits: sockaddrs: <DST,GATEWAY,NETMASK> 10.0.0.0 link#4 255.0.0.0 got message of size 192 on Sat Aug 28 15:57:32 2021 RTM_ADD: Add Route: len 192, pid: 2293, seq 4, errno 22, flags:<UP,PROTO1> locks: inits: sockaddrs: <DST,GATEWAY,NETMASK> 10.42.10.0 link#5 255.255.255.0 In BIRD they look the same as before the upgrade: bird> show route all 10.0.0.0/8 Table master4: 10.0.0.0/8 blackhole [s_null_4 2021-08-28 15:57:32] ! (200) Type: static univ bird> show route all 10.42.10.0/24 Table master4: 10.42.10.0/24 unicast [direct1 2021-08-28 16:07:59] ! (240) dev vlan10 Type: device univ I then decided to try manually adding a blackhole route using "route add -net 10.0.0.0/8 -blackhole -proto1 -nostatic", to get as close to what BIRD was trying to add and noticed that BIRD had a gateway, but "route add" didn't have one. got message of size 184 on Sat Aug 28 16:05:43 2021 RTM_ADD: Add Route: len 184, pid: 2766, seq 1, errno 0, flags:<UP,GATEWAY,DONE,BLACKHOLE,PROTO1> locks: inits: sockaddrs: <DST,NETMASK> 10.0.0.0 255.0.0.0 I tried commenting out line 324 in sysdep/bsd/krt-sock.c of v2.0.8 to see if that could fix it and bird was able to insert the blackhole route (can be seen below), but then bird started dying a couple seconds after starting up, with no error showing up on the logs. got message of size 184 on Sat Aug 28 15:27:33 2021 RTM_ADD: Add Route: len 184, pid: 46425, seq 2, errno 22, flags:<UP,PROTO1> locks: inits: sockaddrs: <DST,NETMASK> 10.42.10.0 255.255.255.0 got message of size 184 on Sat Aug 28 15:27:33 2021 RTM_ADD: Add Route: len 184, pid: 46425, seq 3, errno 0, flags:<UP,GATEWAY,DONE,BLACKHOLE,PROTO1> locks: inits: sockaddrs: <DST,NETMASK> 10.0.0.0 255.0.0.0 At this point, I ran out of ideas on what else to try. This is in a testing environment, so I can easily try things out or provide extra information. Thank you, Luiz

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Re: comparing open source BGP stacks performance
by Justin Pietsch 04 Mar '22

04 Mar '22

(added bird-users@ back, I didn't mean to remove them before) Sorry that I missed that you'd already added the pull request. I merged it. we do need a way to specify exabgp vs bird, but that's just another thing to add. I agree about containers and versions. Just haven't had time to think it through carefully. The policy support is what bgperf had before I forked it. I don't use it, I don't know how to usefully test with it. One more feature I'd like to see, yet I'm not sure how to do this > properly – to make the measurement more accurate, the target should not > only run on its own machine, but bgperf with all the testers should also > watch their load, issuing warning when the bgperf suite may be the > bottleneck. This will probably help testing some hardware routers in a > somehow comparable way. > I agree. My best quick hack for this is to make sure that there are extra resources on the CPU when running. That's why bgperf now tracks %idle. As you can probably tell, bgperf isn't a great architecture now, and I'm trying to get useful results as quickly as possible. So much could be done here. thanks a lot! Justin On Tue, Aug 31, 2021 at 2:30 AM Maria Matejka <maria.matejka(a)nic.cz> wrote: > Hello! > > On 8/31/21 1:29 AM, Justin Pietsch wrote: > > I meant to ask if you'd compared exabgp to bird as testers? I'll try to > > compare later if I have some time. > Well, I have no exact numbers, I just implemented the bird tester and it > seems to eat less memory and less time. You could probably run the same > batch first with exabgp testers and then with bird testers, comparing > how much this affects the results. > > > On Mon, Aug 30, 2021 at 4:27 PM Justin Pietsch <jpietsch(a)gmail.com > > <mailto:jpietsch@gmail.com>> wrote: > > > > This is fantastic!!!! Can you submit those changes as PRs to my > > bgperf? I'm working on moving it to a more permanent place. Then we > > can track issues! :) > > Well, yes, the tester exchange is already there pending: > > https://github.com/jopietsch/bgperf/pull/1 > > and it seems that there are two more from somebody else. > > The tester exchange is anyway quite stupid and may need some similar > code to MRT testers instead of what is there now. > > > your suggestion for specifying branches used to work in bgperf, but > > I broke it in trying to get everything working. I moved some of the > > targets to just download prebuilt docker images, which makes it > > harder. Also with batch I'm not sure how to have multiple versions > > of the same container. Just more things to figure out, but that all > > makes sense. > > I think it would be better to have separate containers for different > branches, yet I couldn't figure out how to do that, except for brutal > solutions which were too disgusting to implement. > > Anyway, when BIRD is used as tester, it shouldn't imho change with the > target, which is probably the main reason why I prefer separate > containers for branches. > > One more thing – when running update -c, the container should also pull, > not only checkout, imho. (Haven't had time to fix this yet.) > > > * fixed policy configuration in BIRD (no clue whether it works > with > > other stacks) > > This may need thorough examination first to formally define what the > policies should mean. It would be really stupid to compare route > filtering with different policies in each stack. > > One more feature I'd like to see, yet I'm not sure how to do this > properly – to make the measurement more accurate, the target should not > only run on its own machine, but bgperf with all the testers should also > watch their load, issuing warning when the bgperf suite may be the > bottleneck. This will probably help testing some hardware routers in a > somehow comparable way. > > Maria >

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Inserting fulltable into kernel FIB makes bird crazy
by Alarig Le Lay 20 Feb '22

20 Feb '22

Hello, Now that the IPv6 bug is supposed to be resolved since 5.8, I tried to upgrade a router from 4.14 to 5.10 Bird starts, however while inserting routes to FIB, I have long I/O loop cycles and at some point bird is unable to keep up. I already recompiled bird in case of a header change or something like that, and to switch to a pre-compiled kernel, neither have any effect. When bird begins to loose track of itself, I have this kind of messages: Sep 24 08:44:43 edge04-hostzealot bird: Netlink: File exists Sep 24 08:44:43 edge04-hostzealot bird: Netlink: File exists Sep 24 08:44:43 edge04-hostzealot bird: Netlink: File exists Sep 24 08:44:43 edge04-hostzealot bird: Netlink: File exists Sep 24 08:44:43 edge04-hostzealot bird: Netlink: File exists Sep 24 08:44:43 edge04-hostzealot bird: ... Sep 24 08:44:43 edge04-hostzealot bird: I/O loop cycle took 28703 ms for 1 events Sep 24 08:44:43 edge04-hostzealot bird: Kernel dropped some netlink messages, will resync on next scan. Sep 24 08:45:50 edge04-hostzealot bird: Netlink: File exists Sep 24 08:45:50 edge04-hostzealot bird: Netlink: File exists Sep 24 08:45:50 edge04-hostzealot bird: Netlink: File exists Sep 24 08:45:50 edge04-hostzealot bird: Netlink: File exists Sep 24 08:45:50 edge04-hostzealot bird: Netlink: File exists Sep 24 08:45:50 edge04-hostzealot bird: ... Sep 24 08:45:51 edge04-hostzealot bird: I/O loop cycle took 36201 ms for 1 events And then ospf begins to flap and routes are re-calculated based on remaining bgp ones. Sep 24 08:46:54 edge04-hostzealot bird: Next hop address 185.107.95.180 resolvable through recursive route for 185.107.92.0/22 (I have a way more specific route in OSPF) I activated the debug, and I can see that bird is re-scanning the entire kernel table when the “I/O loop” message appears Sep 24 09:07:30 edge04-hostzealot bird: kernel_grt_ipv4: 1.0.0.0/24: seen Sep 24 09:07:30 edge04-hostzealot bird: kernel_grt_ipv4: 1.0.4.0/24: seen And it tries to insert already inserted routes Sep 24 09:08:04 edge04-hostzealot bird: kernel_grt_ipv4: 122.76.248.0/23: installing Sep 24 09:08:04 edge04-hostzealot bird: Netlink: File exists And then OSPF is clearly going down Sep 24 09:08:04 edge04-hostzealot bird: ospf_ipv4: Inactivity timer expired for nbr 45.91.126.248 on gre4 Sep 24 09:08:04 edge04-hostzealot bird: ospf_ipv4: Neighbor 45.91.126.248 on gre4 changed state from Full to Down Sep 24 09:08:04 edge04-hostzealot bird: ospf_ipv4: Neighbor 45.91.126.248 on gre4 removed Here are some more detailed logs: https://paste.swordarmor.fr/raw/HX45 https://paste.swordarmor.fr/raw/oM9s This server isn’t the fastest one on the marked, but stuffed enough to handle full views. And with an older kernel it works very well. I have RRs running on 5.10 kernels, so it’s more likely a kernel issue, but I’m not able to determine if it’s caused by the kernel itself or by the way bird is using netlink. I’m using bird 2.0.8, I didn’t try an older version. Thanks a lot, -- Alarig Le Lay

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