From 086140cc46804b676c94472957463055c2f00ed8 Mon Sep 17 00:00:00 2001
From: Gerrit <Gerrit91@users.noreply.github.com>
Date: Mon, 21 Oct 2024 11:43:32 +0200
Subject: [PATCH] Implement mutating webhook for Calico with eBPF
 configuration. (#427)

---
 pkg/webhook/shoot/add.go     |  1 +
 pkg/webhook/shoot/mutator.go | 50 +++++++++++++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/pkg/webhook/shoot/add.go b/pkg/webhook/shoot/add.go
index e3fed946..fe2ed840 100644
--- a/pkg/webhook/shoot/add.go
+++ b/pkg/webhook/shoot/add.go
@@ -25,6 +25,7 @@ func AddToManagerWithOptions(mgr manager.Manager, opts AddOptions) (*extensionsw
 	return shoot.New(mgr, shoot.Args{
 		Types: []extensionswebhook.Type{
 			{Obj: &appsv1.Deployment{}},
+			{Obj: &appsv1.DaemonSet{}},
 			{Obj: &corev1.ConfigMap{}},
 			{Obj: &corev1.Secret{}},
 		},
diff --git a/pkg/webhook/shoot/mutator.go b/pkg/webhook/shoot/mutator.go
index 9cac9c02..8fcedb7f 100644
--- a/pkg/webhook/shoot/mutator.go
+++ b/pkg/webhook/shoot/mutator.go
@@ -3,6 +3,8 @@ package shoot
 import (
 	"context"
 	"fmt"
+	"slices"
+	"strconv"
 
 	extensionswebhook "github.com/gardener/gardener/extensions/pkg/webhook"
 
@@ -48,6 +50,13 @@ func (m *mutator) Mutate(ctx context.Context, new, _ client.Object) error {
 		case "vpn-shoot":
 			extensionswebhook.LogMutation(logger, x.Kind, x.Namespace, x.Name)
 			return m.mutateVPNShootDeployment(ctx, x)
+
+		}
+	case *appsv1.DaemonSet:
+		switch x.Name {
+		case "calico-node":
+			extensionswebhook.LogMutation(logger, x.Kind, x.Namespace, x.Name)
+			return m.mutateCalicoNode(ctx, x)
 		}
 	}
 	return nil
@@ -59,7 +68,7 @@ func (m *mutator) mutateVPNShootDeployment(_ context.Context, deployment *appsv1
 		// raising the timeout to 15 minutes leads to additional 15 minutes of provisioning time because
 		// the nodes cidr will only be set on next shoot reconcile
 		// with the following mutation we can immediately provide the proper nodes cidr and save time
-		logger.Info("ensuring nodes cidr from shoot-node-cidr configmap in vpn-shoot deployment")
+		m.logger.Info("ensuring nodes cidr from shoot-node-cidr configmap in vpn-shoot deployment")
 		c.Env = extensionswebhook.EnsureEnvVarWithName(c.Env, corev1.EnvVar{
 			Name:  "NODE_NETWORK",
 			Value: "",
@@ -76,3 +85,42 @@ func (m *mutator) mutateVPNShootDeployment(_ context.Context, deployment *appsv1
 
 	return nil
 }
+
+func (m *mutator) mutateCalicoNode(_ context.Context, ds *appsv1.DaemonSet) error {
+	if c := extensionswebhook.ContainerWithName(ds.Spec.Template.Spec.Containers, "calico-node"); c != nil {
+		ebpfEnabled := slices.ContainsFunc(c.Env, func(e corev1.EnvVar) bool {
+			if e.Name != "FELIX_BPFENABLED" {
+				return false
+			}
+
+			enabled, _ := strconv.ParseBool(e.Value)
+
+			return enabled
+		})
+
+		if !ebpfEnabled {
+			return nil
+		}
+
+		m.logger.Info("patching calico-node daemon set due to ebpf dataplane being enabled")
+
+		c.Env = extensionswebhook.EnsureEnvVarWithName(c.Env, corev1.EnvVar{
+			Name: "FELIX_BPFDATAIFACEPATTERN",
+			// including "lan" interface name to default value
+			// (see https://github.com/projectcalico/calico/blob/3f7fe4d290541bbdd73c97bdc89a29a29855a48a/felix/config/config_params.go#L180)
+			Value: "^((en|wl|ww|sl|ib)[Popsx].*|(lan|eth|wlan|wwan).*|tunl0$|vxlan.calico$|wireguard.cali$|wg-v6.cali$)",
+		})
+
+		c.Env = extensionswebhook.EnsureEnvVarWithName(c.Env, corev1.EnvVar{
+			Name:  "FELIX_BPFEXTERNALSERVICEMODE",
+			Value: "DSR",
+		})
+
+		c.Env = extensionswebhook.EnsureEnvVarWithName(c.Env, corev1.EnvVar{
+			Name:  "FELIX_MTUIFACEPATTERN",
+			Value: "lan",
+		})
+	}
+
+	return nil
+}