OSPF - lost routes and socket error

27 Aug 2020

      Hi,

I use bird 2.0.7 on FreeBSD 12.1 for 3 routers with bgp and ospf/ospf v3.

This is my weathermap : https://librenms.securmail.fr/weathermap/ (to 
help for understand my network architecture)

I have a configuration for my internal subnet :

protocol ospf ospf_ipv4_internal {
         ipv4 {
                 import keep filtered;
                 import limit 200 action block;
                 import filter {
                         if (net ~ [ 10.0.0.0/8+, 172.16.0.0/12+, 
192.168.0.0/16+ ]) then {
                                 accept;
                         }
                         else {
                                 reject;
                         }
                 };

                 export none;
         };

         area 0.0.0.0 {
                 interface "tap0";
         };
};

The same for IPv6 :

protocol ospf v3 ospf_ipv6_internal {
         ipv6 {
                 import all;
                 import keep filtered;
                 import limit 200 action block;
                 import filter {
                         if (net ~ [ ::/0 ]) then {
                                 reject;
                         }
                         if (net ~ [ fd00:208::/32+ ]) then accept;
                 };

                 export none;
         };

         area 0.0.0.0 {
                 interface "tap0";
         };
};

But, sometimes, ospf_ipv4_internal on 2 routers (always the same) lost 
routes learn by this ospf configuration.

On the router who has the routes (on iFog router) :
bird> show route all protocol ospf_ipv4_internal
Table master4:
192.168.0.0/24       unicast [ospf_ipv4_internal 06:16:20.781] E2 
(150/10/64) [172.16.56.3]
         via 172.16.56.3 on tap0
         Type: OSPF-E2 univ
         OSPF.metric1: 10
         OSPF.metric2: 64
         OSPF.tag: 0x00000000
         OSPF.router_id: 172.16.56.3
172.16.55.0/24       unicast [ospf_ipv4_internal 06:16:14.779] I 
(150/20) [172.16.55.7]
         via 172.16.56.2 on tap0
         Type: OSPF univ
         OSPF.metric1: 20
         OSPF.router_id: 172.16.55.7
172.16.56.0/24       unicast [ospf_ipv4_internal 06:01:36.079] I 
(150/10) [193.148.249.128]
         dev tap0
         Type: OSPF univ
         OSPF.metric1: 10
         OSPF.router_id: 193.148.249.128

On the router who lost them (on Scipio router) :
bird> show route all protocol ospf_ipv4_internal
Table master4:
172.16.56.0/24       unicast [ospf_ipv4_internal 09:33:17.530] I 
(150/10) [89.234.186.30]
     dev tap0
     Type: OSPF univ
     OSPF.metric1: 10
     OSPF.router_id: 89.234.186.30

On this router, in the log file i have this error :
2020-08-27 09:50:12.349 <ERR> ospf_ipv4_internal: Socket error on tap0: 
Invalid argument

The configuration is the same between all routers.

I missed something but i don't understand what ^^

Can you help me on this?

Thanks

OSPF - lost routes and socket error

Boris Tassou