February 2022 - Bird-users

constant for empty prefix set
by Alexander Zubkov 14 Mar '22

14 Mar '22

Hi, I propose to add some constant for empty prefix set, for example (as in the patch): define pfx_empty = [ /empty/ ]; It is useful when we define a named prefix list, which we can use somewhere in filters, but this prefix list is generated, for example, and we may need to make it empty. But there is no currently means to create an empty prefix set, as I understand.

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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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Bird BFD is not compliant to RFC5881
by Christian Bruns 02 Mar '22

02 Mar '22

Hi all, we experienced issues with non-functional BFD Sessions. Debugging yielded that bird does not use RFC compliant BFD Port ranges. RFC 5881 states: "" The source port MUST be in the range 49152 through 65535. ""; however, the port range is not restricted within bird and thus using arbitrary high ports. Some tier 1 transit providers like "Deutsche Telekom" apply strict filter for BFD and only allow RFC5881 compliant ports, hence the issue. There is a workaround to limit the port range globally at system level (/proc/sys/net/ipv4/ip_local_port_range); this seems to work, but we have the strong feeling that restriction of port range for BFD sessions should happen within bird itself. Kind regards, Christian

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flowspec route specification
by Alexander Shikov 28 Feb '22

28 Feb '22

Hello! I'm trying to inject flowspec routes from bird to Juniper MX box: route flow4 { dst 109.68.40.15/32; proto 17; dport 53; } { bgp_ext_community.add( (generic, 0x80060000, 0x0 ) ); }; route flow4 { dst 109.68.40.16/32; proto 17; dport 123; } { bgp_ext_community.add( (generic, 0x80060000, 0x000098968 ) ); }; The second flow specification should apply traffic-rate to traffic, but on Juniper these two flow routes have the same community: minotaur@br1-ki# run show route table DDoS-Mitigation.inetflow.0 detail |match "entry|Comm" 109.68.40.15,*,proto=17,dstport=53/term:3 (1 entry, 1 announced) Communities: traffic-rate:0:0 109.68.40.16,*,proto=17,dstport=123/term:4 (1 entry, 1 announced) Communities: traffic-rate:0:0 Can anyone explain how to correctly set rate-limiting to, for example, 5 Mbps in second specification? Thank you! -- Alexander Shikov Technical Staff, Digital Telecom IX Tel.: +380 44 201 14 07 Mob.: +380 50 410 30 57 http://dtel-ix.net/

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2.0.9 babel interfaces removed after configure
by Johannes Kimmel 27 Feb '22

27 Feb '22

Hi, with bird 2.0.9 previously configured babel interfaces are removed after `birdc configure`. To reproduce the issue I used the following config: router id 127.0.0.1; protocol device { } ipv4 table v4; ipv6 sadr table v6; protocol babel { randomize router id on; ipv4 { table v4; }; ipv6 sadr { table v6; }; interface "dummy0"; } And the following commands: # ip link add dev dummy0 type dummy # ip l set dummy0 up # birdc show babel interfaces BIRD 2.0.9 ready. babel1: Interface State Auth RX cost Nbrs Timer Next hop (v4) Next hop (v6) dummy0 Up No 96 0 2.132 :: fe80::a00c:c0ff:fe44:e43e # birdc configure BIRD 2.0.9 ready. Reading configuration from /etc/bird.conf Reconfigured # birdc show babel interfaces BIRD 2.0.9 ready. babel1: Interface State Auth RX cost Nbrs Timer Next hop (v4) Next hop (v6) # As you can see, without changing the config file, the babel interface disappears after reconfiguring bird. It was suggested to me (thanks nixxda!) that the bug may have been introduced in [1], specifically in line 1757: + if (ic && iface_is_valid(p, iface)) + ic = NULL; The issue might be a missing negation before `iface_is_valid`, though I have not confirmed it myself. Cheers, Johannes Kimmel [1]: https://gitlab.nic.cz/labs/bird/-/commit/c1511b92cc9c215224314be38c28ed8084…

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2.0.9 protocol babel issue
by admin 27 Feb '22

27 Feb '22

Hi,there! I upgraded Bird to 2.0.9, but the Babel protocol could not find neighbors. my interface link is wireguard VPN. how to solve this problem? thank you! this is my configuration,bird 2.0.8 is work. protocol babel { ipv4 { export where (source = RTS_DEVICE) || (source = RTS_BABEL); }; ipv6 { export where (source = RTS_DEVICE) || (source = RTS_BABEL); }; interface "gz-*"; }

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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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Re: BIRD trying to reinsert existing kernel routes, netlink issue?
by Zhaofeng Li 18 Feb '22

18 Feb '22

I know this was an old thread, but would really appreciate if anyone is interested in digging in deeper. I can confirm the exact same behavior happens to me on NixOS with the 5.4.69 kernel but not on 4.19.149. BIRD 2.0.7 on 5.4.69 would incessantly attempt to insert the same routes, rendering birdc unusable as it was presumably taking up so much time in the main loop (it was receiving an IPv4 full table over iBGP as well). While it was doing that, it stopped announcing the prefixes of stub interfaces to OSPF neighbors. Thanks, Zhaofeng Li On Sun, Aug 2, 2020, at 17:36 PM, Sasha Romijn wrote: > Hello, > I’m running into a rather complex issue where BIRD tries to reinsert routes into the kernel routing table that are already in there. I’m at the point of suspecting a netlink bug in the 5.x linux kernel. However, I may be entirely off, and would like to hear what people with more BIRD and/or netlink expertise think about it. > My setup is bird 2.0.7 on Ubuntu 20.04. I’ve been able to reproduce this with the default 5.4.0-42-generic kernel as well as the ubuntu mainline 5.7.0-050700-generic kernel. This bird instance has an IBGP peering with another bird 2.0.7 instance, which sends an IPv4 full table. The IBGP peering is set up over a GRE tunnel. There is no other routing software running. I am seeing this issue on another server too, ubuntu 20.04 with 5.4.0-42-generic. A third one with ubuntu 18.04 and a 4.15.0-20-generic kernel, is fine.

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BIRD incorrectly(?) detects whether a peer is directly connected
by Arsen Arsenović 17 Feb '22

17 Feb '22

Good evening! When configuring BGP on a site BIRD fails to recognize whether an IP is directly connected. It appears to scan over the list of interfaces and check whether their subnets contain the target IP instead of relying on the route table and checking whether the resulting route has a gateway attribute. This does not work in some edge cases (such as, in our case, the machine being configured for a /128 + a LAN route to avoid some Linux autoconfiguration) Perhaps a mechanism like [1] is preferable, where BIRD would query a route from the kernel and check if it has a gateway on it. This is, at least semantically, more correct, as the routing table (at least on Linux) reflects on how addresses are reached exactly, whereas the addresses associated with interfaces serve for autoconfiguration purposes. [1]: https://github.com/shemminger/iproute2/blob/a38d305d15c6a27084d5ebc1c79a831… PS: I'm unsure if my assessment of what currently happens is correct, I apologize if I got it wrong, but at any rate, it definitely fails to recognize that the peer is connected properly in our case. Thanks in advance, -- Arsen Arsenović

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Debian 9, mips debian package
by Skyler Mäntysaari 17 Feb '22

17 Feb '22

Hi there, Could someone please fix up the mips branch so it could get merged someday sooner rather than later? I don't think I can do anything about the issue due to it missing the base image. https://gitlab.nic.cz/labs/bird/-/jobs/549543 Best regards, Skyler

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