bird6: "Netlink: No such process" error from kernel proto on OSPF multipath prefixes

[Vasiliy Tolstov]

23 июля 2015 г. 22:57 пользователь "Israel G. Lugo" <
israel.lugo at tecnico.ulisboa.pt> написал:
>
> Hello,
>
> I am seeing periodic "Netlink: No such process" messages from bird6,
> apparently related to prefixes learned from OSPF where there are two
> equal cost paths. I've got ECMP on, and am installing routes to the
> kernel via kernel protocol.
>
> Operating system is GNU/Linux (Debian), kernel 3.16.
>
> The problem happens when kernel protocol starts pruning table master.
> Apparently, it's always deciding to update these multiple-path routes,
> and has some failure while trying. Log excerpt:
>
>
> bird6: kernel1: fec0:0:0:ffff::2/128: seen
> bird6: kernel1: fec0:0:0:ffff::3/128: seen
> bird6: kernel1: ::/0: seen
> bird6: kernel1: Pruning table master
> bird6: kernel1: 2001:xxx:yyy:z1::/64: updating
> bird6: Netlink: No such process
> bird6: kernel1: 2001:xxx:yyy:z2::/64: updating
> bird6: Netlink: No such process
> ...
>
> This is what "show route" has to say about one of these routes:
>
> bird> show route 2001:xxx:yyy:z1::/64 all
> 2001:xxx:yyy:z1::/64 multipath [backbone 2015-07-21] * IA (150/20)
> [193.aa.bb.137]
>         via fe80::21e:bff:fec1:8c4a on eth1 weight 1
>         via fe80::21e:bff:fec1:8c50 on eth1 weight 1
>         Type: OSPF-IA unicast univ
>         OSPF.metric1: 20
>         OSPF.metric2: 16777215
>         OSPF.tag: 0x00000000
>         OSPF.router_id: 193.aa.bb.137
>
> "show route" periodically displays these routes with a '!' instead of
> '*', indicating a synchronization error.
>
> These "No such process" messages seem to occur every 40 seconds or so.
>
> I am seeing this error both on BIRD 1.4.5 and BIRD 1.5.0.
>
> Relevant topology: Four BIRD routers, A, B, C and D. All in area 0. A+B
> are ABR for area 194, and C+D are ABR for area 165.
>
> A and B announce IA prefixes z1, z2, z3, z4, z5, z6, z7 and z8 with
> equal cost. C and D announce IA prefixes z9 and z10 with equal cost. A
> and B have the error on prefixes from C and D, and vice-versa.
>
> Routes seem to disappear from kernel periodically, and are reinstalled
> again (monitoring with "ip -6 r").
>
> Other routes, non-multipath from other routers, do not seem affected.
>
> Relevant config, from routers C and D:
>
> # common to all routers
> protocol kernel {
>         learn;
>         persist;
>         scan time 20;
>         export all;
> }
>
> protocol ospf backbone {
>         tick 1;
>         ecmp yes;
>         area 0.0.0.0 {
>                 stub no;
>                 interface "eth1" { check link yes; };
>         };
>         area 0.0.165.0 {
>                 stub yes;
>                 summary yes;
>                 interface "eth0.2000" {
>                         type ptp;
>                         check link yes;
>                 };
>                 interface "eth0.141", "eth0.165", "eth0.1411" {
>                         stub;
>                         check link yes;
>                 };
>                 networks {
>                         2001:xxx:yyy:z9::/64;
>                         2001:xxx:yyy:z10::/64;
>                 };
>         };
> }
>
> Routers A and B are similar but different prefixes of course.
>
> I do not see this problem with IPv4 bird (also OSPF, similar
> configuration). Could this be some bug with kernel protocol and
> multipath routes?
>
> I am available for further explanations or more details (logs, configs).
>
> Best regards,

Bird6 does not support ecmp in ipv6. It install and delete routes again on
every sync. We hope that sometimes developers fix this issue.

>
> --
> Israel G. Lugo
> Núcleo de Redes e Comunicações
> Direção de Serviços de Informática
> Instituto Superior Técnico
>
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