February 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.

4 11

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.

2 9

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…

4 3

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

4 5

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

3 7

[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.

3 16

BIRD version 2.0.9
by Ondrej Filip 04 May '22

04 May '22

Dears BIRD users, Roughly after a year, I have got fantastic news for you, we just release a news version 2.0.9. I have to thank my great colleagues! Here is the list of the main features: Version 2.0.9 o BGP: Flowspec validation procedure o Babel: MAC authentication support o Routing table configuration blocks o Optional prefix trie in routing table for faster LPM/interval queries o CLI: New 'show route in <prefix>' command o Filter: Faster (16-way) prefix sets o Filter: MPLS label route attribute o Filter: Operators to pick community components o Filter: Operators to find minimum and maximum element of lists o BGP: New 'free bind' option o BGP: Log route updates that were changed to withdraws o BGP: Improved 'invalid next hop' error reporting o OSPF: Allow ifaces with host address as unnumbered PtP or PtMP ifaces o OSPF: All packets on PtP networks should be sent to AllSPFRouters address o Scripts for apkg-powered upstream packaging for deb and rpm o Support for Blake2s and Blake2b hash functions o Security keys / passwords can be entered in hexadecimal digits o Memory statistics split into Effective and Overhead o Linux: New option 'netlink rx buffer' to specify netlink socket buffer size o BSD: Assume onlink flag on ifaces with only host addresses o Many bugfixes Notes: For OSPF on PtP network, BIRD now sends all packets to multicast AllSPFRouters address (as required in RFC 2328 8.1). This likely breaks setups with multiple neighbors on a network configured as PtP, which worked in previous versions. Such links should be configured as PtMP. Since Linux 5.3, netlink socket can be flooded by route cache entries during route table scan. This version mitigates that issue by using strict netlink filtering.

5 4

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.

3 5

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

3 2

operator to prepend bgp path multiple times
by Alexander Zubkov 14 Mar '22

14 Mar '22

Hi, I suggest to add a new operator: prepend_times(P, A, N) - that will allow to prepend AS A to path P several times (N). Now we need to use some function like this: function add_prepends(int asn, int num) { if num = 1 then { bgp_path.prepend(asn); } else if num = 2 then { bgp_path.prepend(asn); bgp_path.prepend(asn); } else if num = 3 then { ... } Usually the number of prepends is observable, so this function can fit most of cases, but with available operator it will be a bit more convenient, a little syntactic sugar. But it is not something that is hard to live without, of course. In my patch, I chose to "join" implementations of prepend() and prepend_times(). It is questionable, because it requires some additional supporting stuff if I understood right. So may be it is better to implement it as separate operators.

2 2