iBGP routes aren't added in ip route table

[xivamar]

Problem Description:

iBGP routes are not added in ip route table.

OpenSwitch version:

OpenSwitch 0.4.0 (Build: appliance-ops-0.4.0-devel/master-20161216101716-dev)

Test Topology:

Steps to reproduce the problem (see attached file):

1. Configure DUTs as in attached file.

2. Check adjacency and bgp routing table on DUT1. All routes should be in the tables.

     switch# show ip bgp summary 
     BGP router identifier 1.1.1.1, local AS number 77
     RIB entries 2
     Peers 2
   
     Neighbor             AS MsgRcvd MsgSent Up/Down  State
     2.2.2.2              77     295     297 04:51:03 Established
     3.3.3.3              77     296     297 04:51:04 Established
     switch# 
     switch# 
     switch# show ip bgp         
     Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
                   i internal, S Stale, R Removed
     Origin codes: i - IGP, e - EGP, ? - incomplete
   
     Local router-id 1.1.1.1
        Network          Next Hop            Metric LocPrf Weight Path
     *> 11.1.11.0/30     0.0.0.0                  0      0  32768  i
     *>i13.1.32.0/30     3.3.3.3                  0    100      0  i
     Total number of entries 2
     switch# 

3. Check adjacency and bgp routing table on DUT3. All routes should be in the tables.

     switch# show ip bgp summary 
     BGP router identifier 3.3.3.3, local AS number 77
     RIB entries 2
     Peers 2
   
     Neighbor             AS MsgRcvd MsgSent Up/Down  State
     1.1.1.1              77     298     300 04:54:58 Established
     2.2.2.2              77     297     300 04:54:15 Established
     switch# 
     switch# 
     switch# show ip bgp         
     Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
                   i internal, S Stale, R Removed
     Origin codes: i - IGP, e - EGP, ? - incomplete
   
     Local router-id 3.3.3.3
        Network          Next Hop            Metric LocPrf Weight Path
     *>i11.1.11.0/30     1.1.1.1                  0    100      0  i
     *> 13.1.32.0/30     0.0.0.0                  0      0  32768  i
     Total number of entries 2
     switch# 

4. Check routing table on DUT1 and DUT3. - NOK: routing table doesn't contain BGP routes. on DUT1:

    switch# show ip route 
    Displaying ipv4 routes selected for forwarding
    '[x/y]' denotes [distance/metric]
    1.1.1.1/32,  1 unicast next-hops 
       via  loopback1,  [0/0],  connected
    10.1.12.0/30,  1 unicast next-hops 
       via  eth1,  [0/0],  connected
    10.1.23.0/30,  1 unicast next-hops 
       via  10.1.12.2,  [110/20],  ospf
    11.1.11.0/30,  1 unicast next-hops 
       via  eth2,  [0/0],  connected
    2.2.2.2/32,  1 unicast next-hops 
       via  10.1.12.2,  [110/20],  ospf
    3.3.3.3/32,  1 unicast next-hops 
       via  10.1.12.2,  [110/30],  ospf
    switch# 
    switch# 
    switch# show rib 
    Displaying ipv4 rib entries 
    '*' denotes selected
    '[x/y]' denotes [distance/metric]
   
    *1.1.1.1/32,  1 unicast next-hops 
       *via  loopback1,  [0/0],  connected
    1.1.1.1/32,  1 unicast next-hops 
       *via  loopback1,  [110/4000],  ospf
    *10.1.12.0/30,  1 unicast next-hops 
       *via  eth1,  [0/0],  connected
    10.1.12.0/30,  1 unicast next-hops 
       *via  eth1,  [110/41],  ospf
    *10.1.23.0/30,  1 unicast next-hops 
       *via  10.1.12.2,  [110/20],  ospf
    *11.1.11.0/30,  1 unicast next-hops 
       *via  eth2,  [0/0],  connected
    13.1.32.0/30,  1 unicast next-hops 
       via  3.3.3.3,  [200/0],  bgp
    *2.2.2.2/32,  1 unicast next-hops 
       *via  10.1.12.2,  [110/20],  ospf
    *3.3.3.3/32,  1 unicast next-hops 
       *via  10.1.12.2,  [110/30],  ospf
    No ipv6 rib entries 
    switch#

   on DUT3:

    root@switch:~# ip netns exec swns ip route 
    1.1.1.1 via 10.1.23.2 dev eth2  proto zebra  metric 30 
    2.2.2.2 via 10.1.23.2 dev eth2  proto zebra  metric 20 
    10.1.12.0/30 via 10.1.23.2 dev eth2  proto zebra  metric 20 
    10.1.23.0/30 dev eth2  proto kernel  scope link  src 10.1.23.1 
    13.1.32.0/30 dev eth1  proto kernel  scope link  src 13.1.32.1 
    root@switch:~# 
    root@switch:~# 
    root@switch:~# /usr/bin/ovsdb-client dump OpenSwitch Route prefix selected
    Route table
    prefix         selected
    -------------- --------
    "1.1.1.1/32"   true    
    "10.1.12.0/30" true    
    "10.1.23.0/30" []      
    "10.1.23.0/30" true    
    "11.1.11.0/30" false   
    "13.1.32.0/30" true    
    "2.2.2.2/32"   true    
    "3.3.3.3/32"   []      
    "3.3.3.3/32"   true    
    root@switch:~# 

5. Try to send ping from PC1 to PC2 and vice versa. - NOK: Ping is absent.

iBGP_small.txt

[mfirulin]

The function rib_process in the module zebra skips these routes because their next hops are not connected to the corresponding switch and considered "unreachable". The function nexthop_active_ipv4 just passes such next hops (type ZEBRA_ROUTE_OSPF).