Update Node's MAC address to the Node's annotation for direct routing

build/yamls/antrea-aks.yml

@@ -2918,6 +2918,7 @@ rules:
   - get
   - watch
   - list
+  - patch
 - apiGroups:
   - ""
   resources:

build/yamls/antrea-eks.yml

@@ -2918,6 +2918,7 @@ rules:
   - get
   - watch
   - list
+  - patch
 - apiGroups:
   - ""
   resources:

build/yamls/antrea-gke.yml

@@ -2918,6 +2918,7 @@ rules:
   - get
   - watch
   - list
+  - patch
 - apiGroups:
   - ""
   resources:

build/yamls/antrea-ipsec.yml

@@ -2918,6 +2918,7 @@ rules:
   - get
   - watch
   - list
+  - patch
 - apiGroups:
   - ""
   resources:

build/yamls/antrea.yml

@@ -2918,6 +2918,7 @@ rules:
   - get
   - watch
   - list
+  - patch
 - apiGroups:
   - ""
   resources:

build/yamls/base/agent-rbac.yml

@@ -18,6 +18,7 @@ rules:
       - get
       - watch
       - list
+      - patch
   - apiGroups:
       - ""
     resources:

pkg/agent/agent.go

@@ -221,6 +221,10 @@ func (i *Initializer) Initialize() error {
 		return err
 	}
 
+	if err := i.updateNodeMACAnnotation(); err != nil {
+		return err
+	}
+
 	if err := i.setupOVSBridge(); err != nil {
 		return err
 	}

pkg/agent/agent_linux.go

@@ -25,6 +25,10 @@ func (i *Initializer) prepareHostNetwork() error {
 	return nil
 }
 
+func (i *Initializer) updateNodeMACAnnotation() error {
+	return nil
+}
+
 // prepareOVSBridge returns immediately on Linux.
 func (i *Initializer) prepareOVSBridge() error {
 	return nil

pkg/agent/agent_windows.go

@@ -17,16 +17,22 @@
 package agent
 
 import (
+	"context"
+	"encoding/json"
 	"fmt"
 	"net"
 	"strings"
 
 	"github.com/Microsoft/hcsshim"
 	"github.com/rakelkar/gonetsh/netroute"
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	apitypes "k8s.io/apimachinery/pkg/types"
 	"k8s.io/klog"
 
 	"github.com/vmware-tanzu/antrea/pkg/agent/config"
 	"github.com/vmware-tanzu/antrea/pkg/agent/interfacestore"
+	"github.com/vmware-tanzu/antrea/pkg/agent/types"
 	"github.com/vmware-tanzu/antrea/pkg/agent/util"
 	"github.com/vmware-tanzu/antrea/pkg/ovs/ovsctl"
 )
@@ -76,6 +82,35 @@ func (i *Initializer) prepareHostNetwork() error {
 	return util.PrepareHNSNetwork(subnetCIDR, i.nodeConfig.NodeIPAddr, adapter)
 }
 
+// updateNodeMACAnnotation updates the Node's MAC address in the Annotations of the Node. The MAC address will be used
+// for direct routing via Openflow in noencap case.
+func (i *Initializer) updateNodeMACAnnotation() error {
+	if !i.networkConfig.TrafficEncapMode.SupportsNoEncap() {
+		return nil
+	}
+	patch, _ := json.Marshal(map[string]interface{}{
+		"metadata": map[string]interface{}{
+			"annotations": map[string]string{
+				types.NodeMACAddressAnnotationKey: i.nodeConfig.UplinkNetConfig.MAC.String(),
+			},
+		},
+	})
+	var err error
+	for attempt := 0; attempt < 3; attempt++ {
+		_, err = i.client.CoreV1().Nodes().Patch(context.TODO(), i.nodeConfig.Name, apitypes.MergePatchType, patch, metav1.PatchOptions{})
+		if err != nil {
+			if !errors.IsConflict(err) {
+				return err
+			}
+			klog.Warningf("Updating Node MAC annotation failed: %v, will retry", err)
+			continue
+		}
+		klog.Infof("Updating Node MAC annotation succeeded")
+		return nil
+	}
+	return err
+}
+
 // prepareOVSBridge adds local port and uplink to ovs bridge.
 // This function will delete OVS bridge and HNS network created by antrea on failure.
 func (i *Initializer) prepareOVSBridge() error {

pkg/agent/types/annotations.go

@@ -0,0 +1,20 @@
+// Copyright 2021 Antrea Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package types
+
+const (
+	// NodeMACAddressAnnotationKey represents the key of the Node's MAC address in the Annotations of the Node.
+	NodeMACAddressAnnotationKey string = "node.antrea.io/mac-address"
+)