RTC with eBGP doesn't filter routes

[yygit98]

Trying to apply RT constrained filtering (RFC4684) with eBGP but it appears the filtering doesn't work.

Here is the topology: r1(as65001) --- r0(as65000) --- r2(as65002)

r0 config:

global:
  config:
    as: 65000
    router-id: 10.10.10.101

neighbors:
- config:
    neighbor-address: 10.10.10.11
    peer-as: 65001
  afi-safis:
  - config:
      afi-safi-name: l3vpn-ipv4-unicast
      enabled: true
  - config:
      afi-safi-name: rtc
      enabled: true
- config:
    neighbor-address: 10.10.10.12
    peer-as: 65002
  afi-safis:
  - config:
      afi-safi-name: l3vpn-ipv4-unicast
      enabled: true
  - config:
      afi-safi-name: rtc
      enabled: true

r1 config:

global:
  config:
    as: 65001
    router-id: 10.10.10.11

neighbors:
  - afi-safis:
    - config:
        afi-safi-name: l3vpn-ipv4-unicast
        enabled: true
    - config:
        afi-safi-name: rtc
        enabled: true
    config:
      neighbor-address: 10.10.10.101
      peer-as: 65000

run following commands on r1 to advertise:

gobgp vrf add 1 id 1 rd 111:111 rt both 111:111
gobgp vrf add 2 id 2 rd 222:222 rt both 222:222
gobgp vrf 1 rib add 11.11.11.0/24 
gobgp vrf 2 rib add 21.21.21.0/24 

r2 config:

global:
  config:
    as: 65002
    router-id: 10.10.10.12

neighbors:
  - afi-safis:
    - config:
        afi-safi-name: l3vpn-ipv4-unicast
        enabled: true
    - config:
        afi-safi-name: rtc
        enabled: true
    config:
      neighbor-address: 10.10.10.101  
      peer-as: 65000

run following commands on r2 to advertise:

gobgp vrf add 2 id 2 rd 222:222 rt both 222:222
gobgp vrf add 3 id 3 rd 333:333 rt both 333:333
gobgp vrf 2 rib add 22.22.22.0/24
gobgp vrf 3 rib add 32.32.32.0/24

Don't expect RT 333:333 to be shown on r1, but it shows:

$ gobgp global rib -a vpnv4
   Network               Labels     Next Hop             AS_PATH              Age        Attrs
*> 111:111:11.11.11.0/24 [0]        0.0.0.0                                   00:54:37   [{Origin: ?} {Extcomms: [111:111]}]
*> 222:222:21.21.21.0/24 [0]        0.0.0.0                                   00:54:37   [{Origin: ?} {Extcomms: [222:222]}]
*> 222:222:22.22.22.0/24 [0]        10.10.10.101         65000 65002          00:54:30   [{Origin: ?} {Extcomms: [222:222]}]
*> 333:333:32.32.32.0/24 [0]        10.10.10.101         65000 65002          00:54:30   [{Origin: ?} {Extcomms: [333:333]}]

$ gobgp global rib -a rtc
   Network              Next Hop             AS_PATH              Age        Attrs
*> 65001:111:111        0.0.0.0                                   00:57:05   [{Origin: i}]
*> 65001:222:222        0.0.0.0                                   00:57:05   [{Origin: i}]
*> 65002:222:222        10.10.10.101         65000 65002          00:56:58   [{Origin: i}]
*> 65002:333:333        10.10.10.101         65000 65002          00:56:58   [{Origin: i}]

routers have correct capabilities advertised:

$ gobgp neighbor 10.10.10.11
BGP neighbor is 10.10.10.11, remote AS 65001
  BGP version 4, remote router ID 10.10.10.11
  BGP state = established, up for 00:57:54
  BGP OutQ = 0, Flops = 0
  Hold time is 90, keepalive interval is 30 seconds
  Configured hold time is 90, keepalive interval is 30 seconds
  
  Neighbor capabilities:
    multiprotocol:
        l3vpn-ipv4-unicast:	advertised and received
        rtc:	advertised and received
    route-refresh:	advertised and received
    4-octet-as:	advertised and received
  Message statistics:
                         Sent       Rcvd
    Opens:                  1          1
    Notifications:          0          0
    Updates:                4          5
    Keepalives:           116        116
    Route Refresh:          0          0
    Discarded:              0          0
    Total:                121        122
  Route statistics:
    Advertised:             4
    Received:               4
    Accepted:               4

$ gobgp neighbor 10.10.10.12
BGP neighbor is 10.10.10.12, remote AS 65002
  BGP version 4, remote router ID 10.10.10.12
  BGP state = established, up for 00:57:54
  BGP OutQ = 0, Flops = 0
  Hold time is 90, keepalive interval is 30 seconds
  Configured hold time is 90, keepalive interval is 30 seconds
  
  Neighbor capabilities:
    multiprotocol:
        l3vpn-ipv4-unicast:	advertised and received
        rtc:	advertised and received
    route-refresh:	advertised and received
    4-octet-as:	advertised and received
  Message statistics:
                         Sent       Rcvd
    Opens:                  1          1
    Notifications:          0          0
    Updates:                5          4
    Keepalives:           116        116
    Route Refresh:          0          0
    Discarded:              0          0
    Total:                122        121
  Route statistics:
    Advertised:             4
    Received:               4
    Accepted:               4