KNPs tests are failing with endpoint routes enabled

[jibi]

The following KNP tests:

• client-ingress-knp
• client-egress-knp
• client-egress-expression-knp
• echo-ingress-knp

are failing on latest cilium main when endpoint routes is enabled. The failures occur only when testing IPv6 connectivity.

Example run from the main cilium branch: https://github.com/cilium/cilium/actions/runs/4893888862/jobs/8737403663

To reproduce it locally:

diff --git a/Makefile b/Makefile
index 6d8a7e59ad..48fec4150e 100644
--- a/Makefile
+++ b/Makefile
@@ -524,6 +524,7 @@ kind-install-cilium: kind-ready ## Install a local Cilium version into the clust
                --chart-directory=$(ROOT_DIR)/install/kubernetes/cilium \
                --helm-values=$(ROOT_DIR)/contrib/testing/kind-values.yaml \
                --version= \
+               --nodes-without-cilium=kind-worker3 \
                >/dev/null 2>&1 &

 .PHONY: kind-uninstall-cilium
diff --git a/contrib/testing/kind-values.yaml b/contrib/testing/kind-values.yaml
index 04aa85c39b..b7dac02f03 100644
--- a/contrib/testing/kind-values.yaml
+++ b/contrib/testing/kind-values.yaml
@@ -19,9 +19,18 @@ ipv4:
   enabled: true
 bpf:
   monitorAggregation: none
+  masquerade: true
+enableIPv6Masquerade: false
 livenessProbe:
   failureThreshold: 9999
 readinessProbe:
   failureThreshold: 9999
 startupProbe:
   failureThreshold: 9999
+kubeProxyReplacement: "strict"
+tunnelProtocol: "vxlan"
+endpointRoutes:
+  enabled: true

➜  cilium git:(main) WORKERS=3 make kind && make kind-image && make kind-install-cilium

➜  cilium-cli git:(main) make && ./cilium status --wait && ./cilium connectivity test --external-from-cidrs $(kubectl get nodes kind-worker3 -o wide --no-headers | awk '{print $6}')

[pchaigno]

I believe this corresponds to issues cilium/cilium#23910 and cilium/cilium#23852 upstream. cc @jschwinger233

[jschwinger233]

I believe this corresponds to issues cilium/cilium#23910 and cilium/cilium#23852 upstream. cc @jschwinger233

That's right.

[brb]

This got fixed by #1587.