December 2019 - Bird-users

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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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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[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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IPv6 BGP & kernel 4.19
by Robert Sander 25 Aug '21

25 Aug '21

Hi, our routers run on Debian stretch with bird 1.6.4 from bird.network.cz/debian. Yesterday I tried kernel 4.19 from backports.debian.org and ran into a weird issue with IPv6 BGP sessions: All Peerings reported "Error: Hold timer expired" ca. every 40 minutes. IPv6 forwarding was flapping all the time. After rebooting into kernel 4.9 everything worked again. IPv4 BGP was not affected and also OSPF (v4 and v6). I could disable all IPv6 BGP peerings on this router and then it forwarded to another router learned via OSPF for IPv6 without issues. Has anyone seen such a behaviour? Regards -- Robert Sander Heinlein Support GmbH Schwedter Str. 8/9b, 10119 Berlin https://www.heinlein-support.de Tel: 030 / 405051-43 Fax: 030 / 405051-19 Amtsgericht Berlin-Charlottenburg - HRB 93818 B Geschäftsführer: Peer Heinlein - Sitz: Berlin

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Bug: BFD confuses sessions with identical IPv6 link-local addresses
by Julian Brost 14 Jan '21

14 Jan '21

Hi, I just tried to enable BFD for some OSPF and BGP connections and ran into an issue which BFD sessions flapping up and down and Bird logging many messages like these: bfd1: Bad packet from fe80::2 - unknown session id (130079069) bfd1: Bad packet from fe80::2 - unknown session id (3102513000) bfd1: Bad packet from fe80::2 - unknown session id (3650438750) bfd1: Bad packet from fe80::2 - unknown session id (1597034259) This presumably happens due to this piece of code in bfd_rx_hook() in proto/bfd/packets.c: s = bfd_find_session_by_addr(p, sk->faddr); I use fe80::1/fe80::2 as addresses for most of my IPv6 peering connections and sk->faddr is just a 128 bit value, so it contains no interface identifier, which likely leads to Bird confusing multiple BFD sessions. Regards, Julian

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Inject ethernet-based defaults to OSPF
by daniele 04 Dec '20

04 Dec '20

Hello list, I???m looking for some advice from someone that has more experience. I'm running bird 1.6.6. I have two routers R1 and R2, each with a single internet uplink U1 and U2, running OSPF and sharing a LAN ethernet segment. Both U1 and U2 are dhcp-based ethernet segments themselves with a next-hop IP address that can change. I want R1 to be the primary LAN internet gateway and R2 the secondary. Should U1 fail, R1 has to route to R2 in order to reach internet through U2. How would you recommend to inject U1 and U2 default routes into OSPF? I cannot use the next-hop ip address as it changes along time, and an interface-based static route would not work. thanks a lot, d

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BIRD mailing list issue - root cause found: BIRD MTA fails to resend after being greylisted
by Christoph 21 Apr '20

21 Apr '20

Hi, the root cause for the mailing list issues have been found. trubka.network.cz gets greylisted by never tries to delivery the emails again. {{ Oct 4 13:17:46 mx2 postgrey[1652]: action=greylist, reason=new, client_name=trubka.network.cz, client_address=2001:1568:b:145::1 Could you look into your MTA configuration to resolve this issue? thanks, Christoph

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[PATCH] babel: Set onlink flag for IPv4 routes with unreachable next hop
by Toke Høiland-Jørgensen 14 Apr '20

14 Apr '20

If the next hop of a route is not a reachable address, the route should be installed as onlink. This enables a configuration common in mesh networks where the mesh interface is assigned a /32 and babel handles the routing by installing onlink routes. Signed-off-by: Toke Høiland-Jørgensen <toke(a)toke.dk> --- proto/babel/babel.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/proto/babel/babel.c b/proto/babel/babel.c index 88c4711e..4fd88042 100644 --- a/proto/babel/babel.c +++ b/proto/babel/babel.c @@ -640,6 +640,13 @@ babel_announce_rte(struct babel_proto *p, struct babel_entry *e) .nh.iface = r->neigh->ifa->iface, }; + /* If we cannot find a reachable neighbour, set the entry to be onlink. This + * makes it possible to, e.g., assign /32 addresses on a mesh interface and + * have routing work. + */ + if (!neigh_find2(&p->p, &r->next_hop, r->neigh->ifa->iface, 0)) + a0.nh.flags = RNF_ONLINK; + rta *a = rta_lookup(&a0); rte *rte = rte_get_temp(a); rte->u.babel.seqno = r->seqno; -- 2.17.0

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Re: IPv6 BGP & kernel 4.19
by Alarig Le Lay 29 Mar '20

29 Mar '20

We agree then, and I act as a router on all those machines. Le 3 décembre 2019 19:27:11 GMT+01:00, Vincent Bernat <vincent(a)bernat.ch> a écrit : >This is the result of PMTUd. But when you are a router, you don't need >to do that, so it's mostly a problem for end hosts. > >On December 3, 2019 7:05:49 PM GMT+01:00, Alarig Le Lay ><alarig(a)swordarmor.fr> wrote: >>On 03/12/2019 14:16, Vincent Bernat wrote: >>> The information needs to be stored somewhere. >> >>Why has it to be stored? It’s not really my problem if someone else >has >>a non-stantard MTU and can’t do TCP-MSS or PMTUd. >> >>-- >>Alarig > >-- >Sent from my Android device with K-9 Mail. Please excuse my brevity. -- Envoyé de mon appareil Android avec Courriel K-9 Mail. Veuillez excuser ma brièveté.

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