autort rfc8365 / inconsistent derived route target values

[pguibert6WIND]

-ubuntu1804hwe -upstream branch

• kernel 5.4.0-77-generic

summary when modifying 'bgp vrf vrf1 evpn configuration with autort rfc8365 behaviour', I come to a case where the derived route-targets are not the same according to the order of configuration. that issues does not need to peer bgp evpn instances to make it work.

config

ip li add vxl1 type vxlan id 100 local 4.4.4.4
ip li set dev vxl1 up
ip li add vrf1 type vrf table 10
ip li set dev vrf1 up
ip li add dum1 type dummy
ip li set dev dum1 up
ip a a 4.4.4.4/32 dev dum1
brctl addbr br1
brctl addif br1 vxl1
ip li set dev br1 up
ip li set dev br1 master vrf1

• case where it works *

  vrf vrf1
  vni 100
  exit-vrf
  !
  router bgp 100
  bgp router-id 4.4.4.4
  no bgp ebgp-requires-policy
  no bgp suppress-duplicates
  no bgp network import-check
  !
  address-family l2vpn evpn
  advertise-all-vni
  exit-address-family
  !
  router bgp 100 vrf vrf1
  bgp router-id 4.4.4.4
  no bgp ebgp-requires-policy
  no bgp suppress-duplicates
  no bgp network import-check
  !
  address-family ipv4 unicast
  redistribute connected
  exit-address-family
  !
  address-family l2vpn evpn
  autort rfc8365-compatible
  advertise ipv4 unicast
  rd 65000:100
  exit-address-family
  !

  correct show

  dut-vm# show bgp vrf vrf1 vni 
  BGP VRF: vrf1
  Local-Ip: 4.4.4.4
  L3-VNI: 100
  Rmac: 0e:38:03:78:c7:dd
  VNI Filter: none
  L2-VNI List:
  
  Export-RTs:
  RT:100:268435556  
  Import-RTs:
  RT:100:268435556  
  RD: 65000:100
  dut-vm#

• case where it does not work *

  
  vrf vrf1 
  no vni 100
  exit-vrf
  no router bgp 100 vrf vrf1
  vrf vrf1
  vni 100
  exit-vrf
  router bgp 100 vrf vrf1
  bgp router-id 4.4.4.4
  no bgp ebgp-requires-policy
  no bgp suppress-duplicates
  no bgp network import-check
  !
  address-family ipv4 unicast
  redistribute connected
  exit-address-family
  !
  address-family l2vpn evpn
  autort rfc8365-compatible
  advertise ipv4 unicast
  rd 65000:100
  exit-address-family
  !

incorrect show

dut-vm# show bgp vrf vrf1 vni BGP VRF: vrf1 Local-Ip: 4.4.4.4 L3-VNI: 100 Rmac: 0e:38:03:78:c7:dd VNI Filter: none L2-VNI List:

Export-RTs: RT:100:100
Import-RTs: RT:100:100
RD: 65000:100

[pguibert6WIND]

https://github.com/FRRouting/frr/pull/9422

[ton31337]

Fixed by https://github.com/FRRouting/frr/pull/9422.