tested with following script:

systemctl start openvswitch                          
systemctl start ovn-northd
ovn-nbctl set-connection ptcp:6641                                         
ovn-sbctl set-connection ptcp:6642
ovs-vsctl set open . external_ids:system-id=hv1 external_ids:ovn-remote=tcp:127.0.0.1:6642 external_ids:ovn-encap-type=geneve external_ids:ovn-encap-ip=127.0.0.1
systemctl restart ovn-controller
                                       
ovn-nbctl ls-add ls1                         
ovn-nbctl lsp-add ls1 ls1p1                                         
ovn-nbctl lsp-set-addresses ls1p1 "00:00:00:01:01:02 192.168.1.1 2001::1"
ovn-nbctl lsp-add ls1 ls1p2                                              
ovn-nbctl lsp-set-addresses ls1p2 "00:00:00:01:02:02 192.168.1.2 2001::2"
ovn-nbctl lr-add lr1
ovn-nbctl lrp-add lr1 lr1-ls1 00:00:00:00:00:01 192.168.1.254/24 2001::a/64
ovn-nbctl lsp-add ls1 ls1-lr1
ovn-nbctl lsp-set-addresses ls1-lr1 "00:00:00:00:00:01 192.168.1.254 2001::a"
ovn-nbctl lsp-set-type ls1-lr1 router
ovn-nbctl lsp-set-options ls1-lr1 router-port=lr1-ls1
                               
ovn-nbctl lrp-add lr1 lr1-ls2 00:00:00:00:00:02 192.168.2.254/24 2002::a/64
       
ovn-nbctl ls-add ls2
ovn-nbctl lsp-add ls2 ls2-lr1                                            
ovn-nbctl lsp-set-addresses ls2-lr1 "00:00:00:00:00:02 192.168.2.254 2002::a"
ovn-nbctl lsp-set-type ls2-lr1 router                  
ovn-nbctl lsp-set-options ls2-lr1 router-port=lr1-ls2                                                                                                                                                      
ovn-nbctl lsp-add ls2 ls2p1                                                        
ovn-nbctl lsp-set-addresses ls2p1 "00:00:00:02:01:02 192.168.2.1 2002::1"          
                           
ovn-nbctl lsp-add ls1 ls1p3
ovn-nbctl lsp-set-addresses ls1p3 "00:00:00:01:03:02 192.168.1.3 2001::3"

ovn-nbctl set logical_router lr1 options:always_learn_from_arp_request=false

ovs-vsctl add-port br-int ls1p1 -- set interface ls1p1 type=internal external_ids:iface-id=ls1p1
ip netns add ls1p1
ip link set ls1p1 netns ls1p1
ip netns exec ls1p1 ip link set lo up
ip netns exec ls1p1 ip link set ls1p1 address 00:00:00:01:01:02
ip netns exec ls1p1 ip link set ls1p1 up
ip netns exec ls1p1 ip addr add 192.168.1.1/24 dev ls1p1
ip netns exec ls1p1 ip addr add 2001::1/64 dev ls1p1
ip netns exec ls1p1 ip route add default via 192.168.1.254
ip netns exec ls1p1 ip -6 route add default via 2001::a

ovs-vsctl add-port br-int ls1p2 -- set interface ls1p2 type=internal external_ids:iface-id=ls1p2
ip netns add ls1p2
ip link set ls1p2 netns ls1p2
ip netns exec ls1p2 ip link set lo up
ip netns exec ls1p2 ip link set ls1p2 address 00:00:00:01:02:02
ip netns exec ls1p2 ip link set ls1p2 up
ip netns exec ls1p2 ip addr add 192.168.1.2/24 dev ls1p2
ip netns exec ls1p2 ip addr add 2001::2/64 dev ls1p2
ip netns exec ls1p2 ip route add default via 192.168.1.254
ip netns exec ls1p2 ip -6 route add default via 2001::a

ovs-vsctl add-port br-int ls2p1 -- set interface ls2p1 type=internal external_ids:iface-id=ls2p1
ip netns add ls2p1
ip link set ls2p1 netns ls2p1
ip netns exec ls2p1 ip link set lo up
ip netns exec ls2p1 ip link set ls2p1 address 00:00:00:02:01:02
ip netns exec ls2p1 ip link set ls2p1 up
ip netns exec ls2p1 ip addr add 192.168.2.1/24 dev ls2p1
ip netns exec ls2p1 ip addr add 2002::1/64 dev ls2p1
ip netns exec ls2p1 ip route add default via 192.168.2.254
ip netns exec ls2p1 ip -6 route add default via 2002::a

ip netns exec ls1p1 python3 test.py
ovn-sbctl list mac_binding

[root@kvm-01-guest09 bz2211240]# cat test.py 
from scapy.all import *

# Craft the ND broadcast packet
na_packet = Ether(dst="ff:ff:ff:ff:ff:ff")/IPv6(dst="fe80::1")/ICMPv6ND_NA(tgt="fe80::f816:3eff:fe55:a747")

# Send the packet
sendp(na_packet, iface="ls1p1")

reproduced on ovn-2021-21.12.0-103.el9:

[root@kvm-01-guest09 bz2211240]# rpm -qa | grep -E "openvswitch2.17|ovn-2021"                         
openvswitch2.17-2.17.0-92.el9fdp.x86_64                                                               
ovn-2021-21.12.0-103.el9fdp.x86_64                                                                    
ovn-2021-central-21.12.0-103.el9fdp.x86_64                                                            
ovn-2021-host-21.12.0-103.el9fdp.x86_64

+ ip netns exec ls1p1 python3 test.py                                                                 
.                                                                                                     
Sent 1 packets.                                                                                       
+ ovn-sbctl list mac_binding                                                                          
_uuid               : aa677ba7-a4f6-4c4c-9df0-c9c415a73d01                                            
datapath            : 04b2b9b1-36e6-45c8-bfbf-5c5e5c61a999                                            
ip                  : "fe80::f816:3eff:fe55:a747"                                                     
logical_port        : lr1-ls1                                                                         
mac                 : "00:00:00:01:01:02"

<== mac_binding is created

Verified on ovn-2021-21.12.0-134.el9:

[root@kvm-01-guest09 bz2211240]# rpm -qa | grep -E "openvswitch2.17|ovn-2021"                         
openvswitch2.17-2.17.0-92.el9fdp.x86_64
ovn-2021-21.12.0-134.el9fdp.x86_64
ovn-2021-central-21.12.0-134.el9fdp.x86_64                                                            
ovn-2021-host-21.12.0-134.el9fdp.x86_64 

+ ip netns exec ls1p1 python3 test.py                                                                 
.
Sent 1 packets.
+ ovn-sbctl list mac_binding

<== no mac_binding is created

after re-reun the reproducer and add sleep 5 before send NA, the mac_binding is still created when always_learn_from_arp_request is false:

+ ip netns exec ls2p1 ip -6 route add default via 2002::a
+ sleep 5
+ ip netns exec ls1p1 python3 test.py
.
Sent 1 packets.
+ ovn-sbctl list mac_binding
_uuid               : 58a892d7-8208-448e-8726-88ca2dd361a8
datapath            : 09b77f8a-3c67-4351-8125-eda853a02e93
ip                  : "fe80::f816:3eff:fe55:a747"
logical_port        : lr1-ls1
mac                 : "00:00:00:01:01:02"
[root@kvm-01-guest09 bz2211240]# rpm -qa | grep -E "openvswitch2.17|ovn-2021"
openvswitch2.17-2.17.0-92.el9fdp.x86_64
ovn-2021-21.12.0-134.el9fdp.x86_64
ovn-2021-central-21.12.0-134.el9fdp.x86_64
ovn-2021-host-21.12.0-134.el9fdp.x86_64

Ales, could you help to check?

Hi Jianlin,

sorry I was away for a bit. The original reproducer has wrong destionation IP address, so it is in fact
correct that it ends up in the MAC binding table. If you change the packet to the following it shouldn't
end up in the table:

na_packet = Ether(dst="ff:ff:ff:ff:ff:ff")/IPv6(dst="ff00::1")/ICMPv6ND_NA(tgt="fe80::f816:3eff:fe55:a747")


Thanks,
Ales

updated the test.py:

[root@sweetpig-17 bz2213612]# cat test.py 
from scapy.all import *

# Craft the ND broadcast packet
na_packet = Ether(dst="ff:ff:ff:ff:ff:ff")/IPv6(dst="ff01::1", src="fe80::abcd:1")/ICMPv6ND_NA(tgt="fe80::f816:3eff:fe55:a747")


# Send the packet
sendp(na_packet, iface="ls1p1")

and Verified on ovn-2021-21.12.0-134.el9:

+ ip netns exec ls2p1 ip -6 route add default via 2002::a
+ sleep 5
+ ip netns exec ls1p1 python3 test.py
.
Sent 1 packets.
+ ovn-sbctl list mac_binding
[root@sweetpig-17 bz2213612]# rpm -qa | grep -E "openvswitch2.17|ovn-2021"
openvswitch2.17-2.17.0-93.el9fdp.x86_64
ovn-2021-21.12.0-134.el9fdp.x86_64
ovn-2021-central-21.12.0-134.el9fdp.x86_64
ovn-2021-host-21.12.0-134.el9fdp.x86_64

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (ovn-2021 bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:3990