October 2019 - Bird-users

IPv6, route reflectors and link-local nexthops
by Jan-Philipp Litza 11 Nov '19

11 Nov '19

Hi list, maybe this question boils down to "How can I tell bird to always use global IPv6 addresses as nexthops". But let me give you a sketch of my problem: RR ---- R1 ---- R2 Addresses: RR 2001:db8:1::100, fe80:1::100%I1 R1 2001:db8:1::1, fe80:1::1%I1 2001:db8:2::1, fe80:2::1%I2 R2 2001:db8:2::2, fe80:2::2%I2 RR is an route reflector with * a direct iBGP session to R1 / 2001:db8:1::1, and * a multihop eBGP session to R2 / 2001:db8:2::2. As RR isn't supposed to forward any traffic, it has "missing lladdr ignore" set on the iBGP session. R1 and R2 don't talk to each other. Let's suppose R2 announces a route for 2001:db8:3::/64 RR sees this route: > bird> show route all 2001:db8:3::/64 > 2001:db8:3::/64 unicast [R2 2019-10-10 from 2001:db8:2::2] * (100/100) [AS4242424242?] > via fe80:1::1 on I1 > Type: BGP univ > BGP.origin: Incomplete > BGP.as_path: 4242424242 > BGP.next_hop: 2001:db8:2::2 > BGP.local_pref: 100 The nexthop is correctly set to the link-local address of R1 that RR can reach. Notice the missing link-local BGP.next_hop, however. Now RR exports this route to R1, and this is where things go wrong: > bird> show route all 2001:db8:3::/64> 2001:db8:3::/64 unicast [RR 2019-10-10 from 2001:db8:1::100] * (100/0) [AS4242424242?] > via fe80:1::100 on I2 > Type: BGP univ > BGP.origin: Incomplete > BGP.as_path: 4242424242 > BGP.next_hop: 2001:db8:2::2 > BGP.local_pref: 100 R1 correctly identifies the BGP.next_hop as being on-link for I2, but uses the link-local address of RR on the interface to R2 as nexthop. (Actually, it's even worse: R1 doesn't really use fe80:1::100 as nexthop, but the link-local address of the peer that was formerly in the place of RR. That address isn't even present anymore on any server anywhere!) I understand the R1 has no way of knowing the link-local address of R2, because it was never part of the BGP.next_hop. But the link-local address of RR was never part of BGP.next_hop, either! So, Questions: Why does bird use link-local nexthops at all, when all neighbors are configured using global addresses? How is it possible that bird uses the link-local address of RR decoupled from its interface? Is there anything I can do to make R1 use the global address (which is the only address in BGP.next_hop) of R2 as the nexthop? Best regards, Jan-Philipp Litza -- Jan-Philipp Litza PLUTEX GmbH Hermann-Ritter-Str. 108 28197 Bremen Hotline: 0800 100 400 800 Telefon: 0800 100 400 821 Telefax: 0800 100 400 888 E-Mail: support(a)plutex.de Internet: http://www.plutex.de USt-IdNr.: DE 815030856 Handelsregister: Amtsgericht Bremen, HRB 25144 Geschäftsführer: Torben Belz, Hendrik Lilienthal

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Re: Is BIRD on BSD a second class citizen?
by k simon 01 Nov '19

01 Nov '19

Hello, FreeBSD does not support MPLS and VRF, but it support ECMP by recompile kernel with “options RADIX_MPATH”, and quagga/frr have supported it for few years . Not much of people use MPLS on freeware. BSDer always use multi routing tables which FB called FIB to replace VRF. It’s limited, but it’s usable to most people. For the past years, FB has refactored the routing subsystem aimed to reduce contentions on SMP systems, [1][2]. Linux is winner, but now FB can archive up to 10MPPS forward rate on one 8-core x86 server. It’s enough to many people, right ? And FB has an awesome feature called vimage/vnet, it’s similar to LXC on Linux with different implementation. We run serval bird/frr instance in different vnet jail on one host, and run serval on another host for hot backup or load sharing, each instance is independent with ~5% performance loss. Simon Ke 20191031 [1] https://wiki.freebsd.org/ProjectsRoutingProposal [2] https://wiki.freebsd.org/ProjectsRoutingProposal/API

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More BIRD related software?
by Ondrej Zajicek 29 Oct '19

29 Oct '19

Hi I just found another tool related to BIRD and updated and reorganized 'Related software' page on BIRD wiki: https://gitlab.labs.nic.cz/labs/bird/wikis/Related I wonder if you know more software worth mentioning there. -- 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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BFD session status notification
by Winston Chen 29 Oct '19

29 Oct '19

Hi, I am wondering if there is a way an application can be notified when BFD session status changes. I know currently I can check the BFD session by polling with birdc or scanning the log, but if there is some way I get the notification it would help me much more. The reason I am ask this is because when I used keepalived, I found keepalived can send VIP events to an FIFO and my application can get these events from it. Thanks. Chen

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Syntax for show route and primary route (*)?
by Kenth Eriksson 28 Oct '19

28 Oct '19

Hi! When showing routing table, the output can have '*', '!' or empty depending on the route. I thought that the asterisk ('*') meant that the route is a primary route installed into the kernel. But this does not seem to always be true, e.g. consider the following: bird> show route 0.0.0.0/0 Table master4: 0.0.0.0/0 unicast [kernel1 2019-10-22] (215) via 10.210.137.1 on eth1 bird> show route ::0/0 Table master6: ::/0 unicast [static_ipv6 2019-10-22] * (255) via 2a02:1420:1:137::1 on eth1 bird> Why does the default route for IPv6 have a '*' but not for IPv4? Another example where a route pushed to the kernel is not having the '*' mark; bird> show route 10.210.138.64/30 Table master4: 10.210.138.64/30 unicast [ospfv2_1 16:50:34.613] I (145/20) [10.210.138.65] via 10.210.138.66 on p1-2-9-10g0 bird> q ~ # route | grep 10.210.138.64 10.210.138.64 10.210.138.66 255.255.255.252 UG 32 0 0 p1-2-9-10g0 ~ # Thanks, Kenth

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Revalidating RPKI
by Darren O'Connor 23 Oct '19

23 Oct '19

I was reading the documentation for bird2 when I came across this: You can validate routes (RFC 6483) using function roa_check() in filter and set it as import filter at the BGP protocol. BIRD should re-validate all of affected routes after RPKI update by RFC 6811, but we don't support it yet! You can use a BIRD's client command reload in bgp_protocol_name for manual call of revalidation of all routes. Is there a rough timeline for when bird2 will correct re-validate affected routes? As I run multiple table, is the best thing to simply run a cronjob telling bird 'reload in all' a few times a day until that support is added? The second item is this: We currently support just one cache server per protocol. However you can define more RPKI protocols generally. This doesn't seem true though, as I have two cache servers configured for both ipv4 and ipv6 and it seems to be fine? Thanks Darren

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Checking ROA via cli
by Darren O'Connor 23 Oct '19

23 Oct '19

I recently moved from bird to bird2. I'm currently using it as a backend to bgpstuff.net, a looking glass. In order to check the ROA status for a prefix in bird1 I did the following, and got the following result: bird> eval roa_check(roa_table, 71.178.0.0/16, 701) (enum 35)0 That enum I just mapped to the correct ROA_ status. However this same command gives strange output in bird2, sometimes even different when running it more than once: bird> eval roa_check(roa_v4, 71.178.0.0/16, 701) --- 0 ??? <2022> bird> eval roa_check(roa_v4, 71.178.0.0/16, 701) [unknown type 90] Currently running bird 2.0.5 in this instance. Is there a way to get the ROA status like this from the CLI like in bird? Also any ideas why the outputs above are different and seem random? Thanks Darren

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FI_CONDITION must be of type T_BOOL, got 0x00
by Boris Tassou 22 Oct '19

22 Oct '19

Hi, It's my first mail here so, sorry if i missed something. I updated my bird to the 2.0.7 version on a FreeBSD 12.0-RELEASE-p10 and i have an error with a if cond : Oct 22 14:37:32 scipio bird[1199]: filters, line 237: Argument 1 of instruction FI_CONDITION must be of type T_BOOL, got 0x00 The same error at line 227. The conf file : https://paste.swordarmor.fr/4boQ The same filters on Gentoo and same version but without errors. birdc configure doesn't show any errors. Have you an idea? Thanks!

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Centos 8 BIRD 2.0.6 issue with rt_tables parsing
by Igor Gavrilov 22 Oct '19

22 Oct '19

Hello BIRD users. Recently I have upgraded one of our router to Centos 8 with BIRD2 and faced strange issue with rt_tables parsing. When I have custom tables named with capital letters, for example: 128 AAA 129 BBB I get error message while trying to run bird (BIRD version 2.0.6): # bird -p bird: /etc/bird.conf:1:1 Symbol already defined I'm not sure whether it is BIRD issue or Centos one, but to run BIRD I have to change at least one letter in table name to lower case, or change naming length.

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How to enter static prefix with multiple nexthops but no ECMP?
by Kenth Eriksson 21 Oct '19

21 Oct '19

Hi! Does bird support a static prefix with multiple nexthops, without installing all of them in the kernel as ECMP? Trying to do that gives strange results. Consider the following; Add one static route bird> show static 172.20.5.0/24 via 10.210.70.1 bird> bird> show route 172.20.5.0/24 Table master4: 172.20.5.0/24 unicast [static1 15:32:13.352] (200) via 10.210.70.1 on eth0 bird> Add same prefix but pointing to another nexthop bird> show static 172.20.5.0/24 via 10.210.70.1 172.20.5.0/24 via 10.210.70.2 bird> Only second nexthop shows up (ideally would like to see all of them in the RIB, but operationally down) bird> show route 172.20.5.0/24 Table master4: 172.20.5.0/24 unicast [static1 15:32:57.097] (200) via 10.210.70.2 on eth0 bird> Remove one prefix bird> show static 172.20.5.0/24 via 10.210.70.1 bird> Entire prefix is gone. Why is that? bird> show route 172.20.5.0/24 Network not found bird> Is this use case supported? Or only true multi-path is supported? Thanks, Kenth

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