January 2019 - Bird-users

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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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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[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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Bird 1.6.3 removing IPv6 device routes on Linux (3.10.0)
by Ben Arblaster 12 Oct '19

12 Oct '19

Hi, I’m seeing an issue with bird 1.6.3 where IPv6 device routes are unexpectedly removed from the kernel table on Linux (3.10.0, CentOS 7) when bird removes a matching route learned via another protocol (in this case OSPF). To reproduce, I’ve rigged up a very simple test with two bird6 instances running OSPF in a single area 0 over a ptp tunnel. Configs are here - https://gist.github.com/andatche/ca5b5ac120e09b6b8171ec5ca95d2e25 If I add an address/network (e.g. fd00::1/64) to an interface (dummy0) on host A, the route is flooded by A, learned by B and correctly installed in the kernel table on B: fd00::/64 via fe80::5efe:ae2:b006 dev tun0 proto bird metric 1024 If I then add the same address/network (e.g. fd00::1/64) to an interface (dummy0) on host B, at that instant a device route is installed in the kernel table alongside the existing route on host B and it now looks like this: fd00::/64 dev dummy0 proto kernel metric 256 fd00::/64 via fe80::5efe:ae2:b006 dev tun0 proto bird metric 1024 Shortly after, bird picks up the new address/network on dummy0, recalculates the area and correctly selects the connected route as the new best. It then removes the old route via host A from the kernel table, as expected: kernel1 < removed fd00::/64 via fe80::5efe:ae2:b006 on tun0 However, this causes both the route via host A *and* the device route to be removed from the kernel table, leaving the kernel table on host B with no route to fd00::/64 at all. # ip -6 route show fd00::/64 # This is a change in behaviour from 1.4.5 and seems like a bug, rather than the expected behaviour? Regards, Ben -- Ben Arblaster e: ben(a)andatche.com t: +447943860840 w: https://andatche.com

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For developer, required some explanation on code with timer and BGP
by Mattia Milani 06 Apr '19

06 Apr '19

Hello all, this is a message for developer and who know how bird use timer, and buffer. Sorry for the length of this mail. For first, the protocol i want to modify and upgrade is BGP, i see that there isn't the timer MRAI implemented and it will be useful for some studies on information propagation, so i decided to develop a first version of it. The actual process to send any kind of pkt is to call the function bgp_fire_tx() and it's called by two other function respectively bgp_kick_tx() and bgp_tx() and the function bgp_fire_tx() take care to read from the buffer the message that has to be sent and send it. bgp_kick_tx() and bgp_tx() call bgp_fire_tx() while it don't return 0, so the clear all the buffer of the message that has to be sent. So my idea to introduce MRAI was that: Create a timer (for now I created it for connection, after like say RFC 4271 this timer has to be set for every route) and put it on the connection. Initialize it with the other timer of the conn when the state of the conn goes up i set it to some value and start the timer. when the timer finish i call the function MRAI_finish() that call the function bgp_fire_tx() while there is something to send more ore less like the while loop in bgp_kick_tx() and bgp_tx() when it's called bgp_fire_tx() on the update message part i written a check, if the timer isn't at 0 i can't send the update, because the function can be called from bgp_kick_tx() or bgp_tx(), but if it 0 it is finished so i can send the message When all the message had been send i reset the timer and start it again. But unfortunately i see something that doesn't make my code work. when something call bgp_kick_tx() or bgp_tx() the call bgp_fire_tx() and they clear all the buffer, including update message that wasn't sended so when the timer finish it didn't found anything on the buffer. Now how can i change that? My idea is to use a secondary buffer, when in bgp_fire_tx() i see that i can't send the update I will insert the pkt in this secondary buffer and consume the pkt on the main buffer. when bgp_kick_tx() or bgp_tx() have send all the messages I will transfer all the pkt in the secondary buffer into the main buffer. So I ask you it's possible that? there is something in the code already written that could help me? do you see another way to implement the MRAI timer? Thanks a lot to everyone, Mattia

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BGP update schedule problem
by Mattia Milani 04 Feb '19

04 Feb '19

Hello all, I don't know if anyone can help me but this is my problem: I want to trigger an UPDATE message in some situations, so I inserted a: bgp_schedule_packet(pr->conn, ch, PKT_UPDATE); In the point that I want to schedule it, pr->conn and ch refer to the correct connection and channel where I want to send the UPDATE. My question is now how can I trigger the sending of the UPDATE? because looking in the logs I correctly schedule the UPDATE but it isn't sent after a while. Thanks, Mattia

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Way too many routes imported in OSPF
by Alarig Le Lay 29 Jan '19

29 Jan '19

Hi, I’ve set up an OSPF as an IGP to resolve the BGP next-hops on the routes learned from eBGP sessions. On one of my border routers (running FreeBSD), the counters are correct: root@nominoe:~ # birdc 'show protocols all "ospf_*"' BIRD 2.0.2 ready. Name Proto Table State Since Info ospf_ipv4 OSPF master4 up 16:29:14.755 Running Channel ipv4 State: UP Table: master4 Preference: 150 Input filter: (unnamed) Output filter: (unnamed) Import limit: 200 Action: block Routes: 59 imported, 0 filtered, 26 exported Route change stats: received rejected filtered ignored accepted Import updates: 114 0 0 0 114 Import withdraws: 43 0 --- 0 43 Export updates: 4343089 79 4342789 --- 221 Export withdraws: 25677 --- --- --- 195 ospf_ipv6 OSPF master6 up 16:29:14.755 Running Channel ipv6 State: UP Table: master6 Preference: 150 Input filter: (unnamed) Output filter: (unnamed) Import limit: 200 Action: block Routes: 16 imported, 0 filtered, 13 exported Route change stats: received rejected filtered ignored accepted Import updates: 178 0 0 0 178 Import withdraws: 161 0 --- 0 161 Export updates: 210288 168 210107 --- 13 Export withdraws: 4415 --- --- --- 0 On the other (running Gentoo), I can’t have so much: asbr02 ~ # birdc 'show protocols all "ospf_*"' BIRD 2.0.3 ready. Name Proto Table State Since Info ospf_ipv4 OSPF master4 up 17:07:45.751 Running Channel ipv4 State: UP Table: master4 Preference: 150 Input filter: (unnamed) Output filter: (unnamed) Import limit: 200 Action: block Routes: 64 imported, 0 filtered, 4294120544 exported Route change stats: received rejected filtered ignored accepted Import updates: 258 0 0 0 258 Import withdraws: 181 0 --- 0 181 Export updates: 2107116 242 2106865 --- 9 Export withdraws: 21844 --- --- --- 846761 ospf_ipv6 OSPF master6 up 17:02:14.667 Running Channel ipv6 State: UP Table: master6 Preference: 150 Input filter: (unnamed) Output filter: (unnamed) Import limit: 200 Action: block Routes: 19 imported, 0 filtered, 4294870086 exported Route change stats: received rejected filtered ignored accepted Import updates: 204 0 0 0 204 Import withdraws: 185 0 --- 0 185 Export updates: 325977 194 325773 --- 10 Export withdraws: 10926 --- --- --- 97220 asbr02 ~ # birdc 'show route count table master4' BIRD 2.0.3 ready. 2461149 of 2461149 routes for 737465 networks in table master4 asbr02 ~ # birdc 'show route count table master6' BIRD 2.0.3 ready. 239266 of 239266 routes for 63527 networks in table master6 I already tried to restart the protocols, but it doesn’t change anything. Any idea? Thanks, -- Alarig

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Default config file name 1.6 vs. 2.0
by Eugene Crosser 28 Jan '19

28 Jan '19

Hello, I would like to suggest to change the default name of the configuration file for bird version 2.0. The two bird versions cannot use the same file because of syntax change. And some of us distribute the file via configuration management tools (like ansible etc.). This makes upgrade path rather difficult and unnecessarily error-prone: you need to synchronize exchange of the version of the configuration file with upgrade (or downgrade! That can be necessary too!) of the bird package. Whereas if different versions used different files, you could distribute both files with you configuration management tool in advance, and then gradually upgrade the package, with easy rollback if things do not go well. Even if configuration management is not used, it is still more convenient to be able to start one or the other version of the daemon without the need to specify alternative configuration, or replacing the file. Thanks for consideration! Eugene

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Exporting multipath link routes from Linux kernel
by Eugene Crosser 28 Jan '19

28 Jan '19

Hello all, we do virtual hosting, and we provide routeable /32 addresses to the guests. Kernel routes on the KVM host are link routes that look like this: 1.0.0.113 dev pub020304050612 proto static They are picked up by bird and exported to the core router. When we launch multiple guests with the same address on multiple hosts, this results in an ECMP route on the core router, providing load balancing. This all works fine until we launch more than one guest with the same address on _one_ host. We create kernel multipath route that looks like this: 1.0.0.115 proto static metric 10 nexthop dev pub020304050612 weight 1 nexthop dev pub020304050616 weight 1 Note that there is no "via" address in the hop configulations! This actually works, i.e. connections originating from the host are balanced between those guests. But bird refuses to pick up such route because of the code here: https://gitlab.labs.nic.cz/labs/bird/blob/master/sysdep/linux/netlink.c#L528 Questions: 1. What was the justification for disallowing gateway-less multipath routes? Would it make sense to allow them (in the mainstream code)? 2. Would it be sufficient to simply drop the check for the presence of the gateway address in the message, and return `first` even if gateway address was not present? Thank you, Eugene

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