Routes imported from BGP doesn't have proper gateways

[Ooth Gray]

Hi I'm having troubles in BIRD configuration, and I'm pretty sure it's just
a trivial wrong configure issue but I really tried my best >_<

Let me give you some background.

1. There are 2 hosts connected by wire (so that they are L2 reachable), one
with IPv4 10.22.12.88, and another is 10.22.12.44. Here's one the arp
record from "ip neigh sh":

> 10.22.12.88 dev bond0 lladdr f8:6e:ee:8b:cf:90 REACHABLE
>

2. Both 2 hosts have some KVM virtual machines, with corresponding routes
from host to vm, here's one of the routes from "ip r":

> 10.233.25.178 dev yap35caa1e88854  scope link  src 10.22.12.44

The 10.233.25.178 is the address of a VM, and the dev yap35caa1e88854 is a
tap device connecting eth0 inside the VM.

What I want to do is to build routes between these 2 hosts, in order to let
VMs on host A be able to connect VMs on host B.

Hope I make myself clear.

So I'm using BIRD 2.0.3 on Ubuntu 16.04, with the config file as follows:

log syslog all;
> router id 10.22.12.44;
>
> protocol device {
>   debug { states };
>   scan time 2;}
>
> protocol kernel {
>         learn;
>         persist;
>         scan time 10;
>         ipv4 {
>                 import all;
>                 export all;
>         };}
>
> protocol bgp {
>         debug { states };
>         local as 65000;
>         neighbor 10.22.12.88 as 65000;
>         source address 10.22.12.44;
>         multihop;
>         ipv4 {
>                 export filter {
>                         if ( net ~ 10.233.0.0/16 ) then {
>                                 accept;
>                         }
>                         reject;
>                 };
>                 import all;
>                 next hop self on;
>                 gateway recursive;
>                 add paths on;
>         };}
>
>
But this doesn't work well, the peer BIRD show the info as follows:

bird> show route protocol bgp1
> Table master4:10.233.25.178/32     unicast [bgp1 18:47:32.910 from 10.22.12.44] * (100/?) [i]
> 	via 10.22.12.1 on enp2s0f0 onlink
> bird> show route export kernel1
> Table master4:10.233.25.178/32     unicast [bgp1 18:47:32.910 from 10.22.12.44] * (100/?) [i]
> 	via 10.22.12.1 on enp2s0f0 onlink
>
>
The problem happened on the gateway, I was hoping the routes should have
"via 10.22.12.44" instead of "via 10.22.12.1";

10.22.12.1 came from the host default gateway:

> default via 10.22.12.1 dev bond0 onlink

But I have no idea how to prevent BIRD from using it.

The other information may be helpful is included below:

bird> show protocols all bgp1
> Name       Proto      Table      State  Since         Info
> bgp1       BGP        ---        up     18:28:46.888  Established
>   BGP state:          Established
>     Neighbor address: 10.22.12.88
>     Neighbor AS:      65000
>     Neighbor ID:      10.22.12.88
>     Local capabilities
>       Multiprotocol
>         AF announced: ipv4
>       Route refresh
>       Graceful restart
>       4-octet AS numbers
>       ADD-PATH        RX: ipv4        TX: ipv4
>       Enhanced refresh
>       Long-lived graceful restart
>     Neighbor capabilities
>       Multiprotocol
>         AF announced: ipv4
>       Route refresh
>       Graceful restart
>       4-octet AS numbers
>       Enhanced refresh
>       Long-lived graceful restart    Session:          internal multihop AS4
>     Source address:   10.22.12.44
>     Hold timer:       117.086/240
>     Keepalive timer:  52.520/80
>   Channel ipv4    State:          UP    Table:          master4    Preference:     100
>     Input filter:   ACCEPT
>     Output filter:  (unnamed)    Routes:         2 imported, 20 exported
>     Route change stats:     received   rejected   filtered    ignored   accepted
>       Import updates:              2          0          0          0          2
>       Import withdraws:            0          0        ---          0          0
>       Export updates:             49          6         23        ---         20
>       Export withdraws:            0        ---        ---        ---          4
>     BGP Next hop:   10.22.12.44
>     IGP IPv4 table: master4
>
> bird> show route export bgp1
> Table master4:10.233.25.178/32     unicast [kernel1 18:04:09.483] (10)
> 	dev yap35caa1e88854
>
>
Please enlighten me with some advice, and I'll appreciate that very much.

Thank you!
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