Incorrect neighbor table entry in stateless-lb-frontend

[LionelJouin]

Describe the bug

It seems the neighbor table entries are not cleaned correctly in the stateless-lb-frontend even after this fix: https://github.com/Nordix/Meridio/pull/334. I observed the problem in this run: https://jenkins.nordix.org/blue/organizations/jenkins/meridio-e2e-test-kind/detail/meridio-e2e-test-kind/11226/pipeline/22

To Reproduce ?

Expected behavior /

Context

• Meridio: v1.0.1

Logs

ip neighbor in stateless-lb-frontend (red.stateless-lb-frontend-attractor-a-1-6cdff6b9f6-tcpgr.ip-neighbour.txt):

169.254.100.150 dev ext-vlan0 lladdr 02:42:ac:12:00:05 REACHABLE
10.244.2.1 dev eth0 lladdr 22:a5:19:f9:18:eb REACHABLE
172.16.16.10 dev conduit-a--b8aa lladdr 02:fe:cd:19:97:a2 STALE

ip a in a target (red.target-a-6ff9898648-xg6t5.ip-a.txt):

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0@if27: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 82:b7:0d:21:1c:8c brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.244.1.26/24 brd 10.244.1.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::80b7:dff:fe21:1c8c/64 scope link 
       valid_lft forever preferred_lft forever
3: nsm-0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UNKNOWN group default qlen 1000
    link/ether 02:fe:cf:c6:58:ba brd ff:ff:ff:ff:ff:ff
    inet 172.16.16.10/24 brd 172.16.16.255 scope global nsm-0
       valid_lft forever preferred_lft forever
    inet 20.0.0.1/32 scope global nsm-0
       valid_lft forever preferred_lft forever
    inet6 fe80::fe:cfff:fec6:58ba/64 scope link 
       valid_lft forever preferred_lft forever

e2e tests:

IngressTraffic UDP-IPv4 when Send udp traffic in trench-a with vip-1-v4 as destination IP and udp-destination-port-0 as destination port (Traffic) is received by the targets
/home/jenkins/nordix/slave_root/workspace/meridio-e2e-test-kind/11226/test/e2e/ingress_traffic_test.go:84
  STEP: Sending udp traffic from the TG trench-a.red to 20.0.0.1:4003 @ 02/23/23 04:16:38.498
  STEP: Handling the error, collecting the logs: true @ 02/23/23 04:18:38.723
  [FAILED] in [It] - /home/jenkins/go/pkg/mod/github.com/onsi/[email protected]/internal/assertion.go:62 @ 02/23/23 04:22:55.031
• [FAILED] [376.534 seconds]
IngressTraffic UDP-IPv4 when Send udp traffic in trench-a with vip-1-v4 as destination IP and udp-destination-port-0 as destination port [It] (Traffic) is received by the targets
/home/jenkins/nordix/slave_root/workspace/meridio-e2e-test-kind/11226/test/e2e/ingress_traffic_test.go:84
  [FAILED] All targets with the stream opened should have received traffic: map[target-a-6ff9898648-k7qbv:53 target-a-6ff9898648-rw96z:55 target-a-6ff9898648-xhgwf:54]
  Expected
      <int>: 3
  to equal
      <int>: 4
  In [It] at: /home/jenkins/go/pkg/mod/github.com/onsi/[email protected]/internal/assertion.go:62 @ 02/23/23 04:22:55.031

log_collector_1677125798497966606.zip