"<ERR> bfd1: Socket error: Destination address required"

[Fran]

Non-multi-hop iBGP neighbors via wireguard tunnel.

The WG interfaces have a /64 each and multiple BGP/BFD neighbors are 
located in each of the /64s via the WG interfaces.

BGP sessions are using interface IPv6 addresses and are working fine for 
 > 1y.


On 29/04/2024 20:05, Bernd Naumann via Bird-users wrote:
> Are your neighbors directly connected or by any chance multihop?
> 
> On 29.04.24 7:41 PM, Fran via Bird-users wrote:
>> Hello Alexander,
>>
>> thanks for your email.
>>
>> I started without any neighbor config in the BFD section and the error
>> message was there, while trying to get rid of the error I first added
>> the "local <IP address>"  and then the "dev <interface>" options. The
>> error message appears non the less.
>>
>> Best,
>>
>> fran
>>
>>
>>
>> On 29/04/2024 17:20, Alexander Zubkov wrote:
>>> Hi,
>>>
>>> You do not need to define neighbors for BGP sessions explicitly in
>>> your BFD config. They are created automatically for BGP sessions with
>>> BFD enabled. In that case, I suppose, you won't get errors for the
>>> missing neighbors.
>>>
>>> Regards,
>>> Alexander
>>>
>>> On Mon, Apr 29, 2024 at 1:16 PM Fran via Bird-users
>>> <bird-users at network.cz> wrote:
>>>>
>>>> Hello there,
>>>>
>>>> I get the error message:
>>>>
>>>> "<ERR> bfd1: Socket error: Destination address required"
>>>>
>>>> (ubuntu 22.04, bird via ppa 2.15.1) running BFD and MP-BGP via IPv6 over
>>>> wireguard interfaces. Not all BGP neighbors are reachable.
>>>>
>>>> Relevant (I hope) config:
>>>>
>>>> log "/var/log/bird/bird.log" all;
>>>>
>>>> protocol device {
>>>> }
>>>>
>>>> protocol bfd {
>>>>      accept ipv6 direct;
>>>>      interface "wg_blue*";
>>>>      interface "wg_green" {
>>>>        multiplier 3;
>>>>        interval 500 ms;
>>>>      };
>>>>      neighbor 2001:db8:f000::2 dev "wg_green" local 2001:db8:f000::1;
>>>>      neighbor 2001:db8:f000:ffff::2 dev "wg_blue2" local
>>>> 2001:db8:f000:ffff::1;
>>>>      neighbor 2001:db8:f000:fffc::5 dev "wg_blue1" local
>>>> 2001:db8:f000:fffc::1;
>>>>      neighbor 2001:db8:f000:fffc::4 dev "wg_blue1" local
>>>> 2001:db8:f000:fffc::1;
>>>>      neighbor 2001:db8:f000:fffc::3 dev "wg_blue1" local
>>>> 2001:db8:f000:fffc::1;
>>>>      neighbor 2001:db8:f000:fffc::2 dev "wg_blue1" local
>>>> 2001:db8:f000:fffc::1;
>>>> }
>>>>
>>>>
>>>> protocol bgp EXAMPLE {
>>>>      local as 65001;
>>>>      neighbor 2001:db8:f000::2 as 65044;
>>>>      direct;
>>>>      med metric yes;
>>>>      ipv4 {
>>>>        ...
>>>>      };
>>>>      ipv6 {
>>>>        ...
>>>>      };
>>>>      bfd on;
>>>> }
>>>>
>>>>
>>>> If I remove the BFD config for the non-established BGP neighbors, the
>>>> error message disappears (although there are still non-established BFD
>>>> sessions for established BGP neighbors (BFD not yet confed on the other
>>>> end)).
>>>>
>>>> At first I did not create neighbor statements for BFD, then I added
>>>> "dev" and "local" options - no improvement.
>>>>
>>>> No revelations with "debug protocols all".
>>>>
>>>> Any ideas? Thanks a lot!
>>>>
>>>> Best,
>>>>
>>>> fran
>