Unreachable next-hop over bgp

[Alex Bligh]

Another bird newbie question I'm afraid. I have the following config:

          10.255.199.3   10.255.199.1
 [Quagga]----------------------------- [BIRD]
               10.255.199.0/24

My bird config and quagga config are at the bottom of this email.

Bird is learning a kernel route (6.6.6.6) and advertising it to quagga.
This works fine.

Quagga is originating a default route (0.0.0.0/32) and advertising it
to bird. The advertisement works fine, but I see:

bird> show route
6.6.6.6/32         via 10.99.99.2 on dummy [kernel1 18:02] * (10)
0.0.0.0/0          unreachable [MyBGP 18:26 from 10.255.199.1] * (100/-) [i]
bird> show route 0.0.0.0/0 all
0.0.0.0/0          unreachable [MyBGP 18:26 from 10.255.199.1] * (100/-) [i]
        Type: BGP unicast univ
BGP.origin: IGP
BGP.as_path:
BGP.next_hop: 10.255.199.1
BGP.local_pref: 100

Bird has marked the route as unreachable. Obviously the route is
not unreachable, because it is the next hop (quagga is doing
next-hop-self).

The only reason for this I can see is because bird is determining
reachability on the basis of its FIB only (as opposed to the kernel
routing table) and there is no FIB entry for 10.255.199.0/24
(from show route).

How are such interface routes meant to get into the FIB?

-- 
Alex Bligh


Bird config:

protocol kernel {
        persist;                # Don't remove routes on bird shutdown 

        scan time 10;           # Scan kernel routing table every 20 
seconds
        import all;
        export all;
        learn;                  # Learn all alien routes from the kernel 

}

# This pseudo-protocol watches all interface up/down events. 

protocol device {
        scan time 10;           # Scan interfaces every 10 seconds 

}

protocol bgp MyBGP {
         local as 65000;
         neighbor 10.255.199.1 as 65000;
         export filter {
                accept;
         };
         import filter {
                accept;
         };
         next hop self;
         import all;
	 export	all;
}


Quagga config:

router bgp 65000
 bgp router-id 10.255.199.1
 neighbor 10.255.199.3 remote-as 65000
 neighbor 10.255.199.3 next-hop-self
 neighbor 10.255.199.3 default-originate
 neighbor 10.255.199.3 soft-reconfiguration inbound

Log from Quagga

2011/08/17 18:19:43 BGP: 10.255.199.3 went from Idle to Connect
2011/08/17 18:19:43 BGP: 10.255.199.3 passive open
2011/08/17 18:19:43 BGP: 10.255.199.3 went from Active to OpenSent
2011/08/17 18:19:43 BGP: 10.255.199.3 rcv message type 1, length (excl. 
header) 26
2011/08/17 18:19:43 BGP: 10.255.199.3 rcv OPEN, version 4, remote-as (in 
open) 65000, holdtime 240, id 10.99.99.1
2011/08/17 18:19:43 BGP: 10.255.199.3 sending OPEN, version 4, my as 65000, 
holdtime 180, id 10.255.199.1
2011/08/17 18:19:43 BGP: 10.255.199.3 send message type 1, length (incl. 
header) 53
2011/08/17 18:19:43 BGP: 10.255.199.3 rcv OPEN w/ OPTION parameter len: 16
2011/08/17 18:19:43 BGP: 10.255.199.3 rcvd OPEN w/ optional parameter type 
2 (Capability) len 14
2011/08/17 18:19:43 BGP: 10.255.199.3 OPEN has MultiProtocol Extensions 
capability (1), length 4
2011/08/17 18:19:43 BGP: 10.255.199.3 OPEN has MP_EXT CAP for afi/safi: 1/1
2011/08/17 18:19:43 BGP: 10.255.199.3 OPEN has Route Refresh capability 
(2), length 0
2011/08/17 18:19:43 BGP: message index 65 [4-octet AS number] found in 
position 4 (max is 8)
2011/08/17 18:19:43 BGP: 10.255.199.3 OPEN has 4-octet AS number capability 
(65), length 4
2011/08/17 18:19:43 BGP: 10.255.199.3 went from OpenSent to Deleted
2011/08/17 18:19:43 BGP: 10.255.199.3 send message type 4, length (incl. 
header) 19
2011/08/17 18:19:43 BGP: 10.255.199.3 went from OpenSent to OpenConfirm
2011/08/17 18:19:43 BGP: 10.255.199.3 rcv message type 4, length (excl. 
header) 0
2011/08/17 18:19:43 BGP: 10.255.199.3 went from OpenConfirm to Established
2011/08/17 18:19:43 BGP: 10.255.199.3 send message type 4, length (incl. 
header) 19
2011/08/17 18:19:43 BGP: 10.255.199.3 send UPDATE 0.0.0.0/0 nexthop 
10.255.199.1, origin i, mp_nexthop ::, path
2011/08/17 18:19:43 BGP: 10.255.199.3 rcvd UPDATE w/ attr: nexthop 
10.255.199.3, origin i, localpref 100, path
2011/08/17 18:19:43 BGP: 10.255.199.3 rcvd 6.6.6.6/32