Set gateway_mtu on rtos-<node> router ports

This allows ovn_cluster_router to send ICMP needs frag when too large of
a packet is sent from a pod (such as from a kubevirt VM with too large
an MTU).

See https://issues.redhat.com/browse/FDP-1295 for more details.

Signed-off-by: Tim Rozet <[email protected]>

Author: trozet

go-controller/pkg/ovn/base_network_controller.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"reflect"
+	"strconv"
 	"sync"
 	"time"
 
@@ -383,6 +384,9 @@ func (bnc *BaseNetworkController) syncNodeClusterRouterPort(node *corev1.Node, h
 		Name:     lrpName,
 		MAC:      nodeLRPMAC.String(),
 		Networks: lrpNetworks,
+		Options: map[string]string{
+			"gateway_mtu": strconv.Itoa(config.Default.MTU),
+		},
 	}
 	logicalRouter := nbdb.LogicalRouter{Name: logicalRouterName}
 	gatewayChassis := nbdb.GatewayChassis{
@@ -392,7 +396,7 @@ func (bnc *BaseNetworkController) syncNodeClusterRouterPort(node *corev1.Node, h
 	}
 
 	err = libovsdbops.CreateOrUpdateLogicalRouterPort(bnc.nbClient, &logicalRouter, &logicalRouterPort,
-		&gatewayChassis, &logicalRouterPort.MAC, &logicalRouterPort.Networks)
+		&gatewayChassis, &logicalRouterPort.MAC, &logicalRouterPort.Networks, &logicalRouterPort.Options)
 	if err != nil {
 		klog.Errorf("Failed to add gateway chassis %s to logical router port %s, error: %v", chassisID, lrpName, err)
 		return err

go-controller/pkg/ovn/master_test.go

@@ -335,6 +335,9 @@ func addNodeLogicalFlowsHelper(testData []libovsdbtest.TestData, expectedOVNClus
 		MAC:            node.NodeLRPMAC,
 		Networks:       []string{node.NodeGWIP},
 		GatewayChassis: []string{chassisName + "-UUID"},
+		Options: map[string]string{
+			"gateway_mtu": "1400",
+		},
 	})
 	if serviceControllerEnabled {
 		testData = append(testData, &nbdb.ChassisTemplateVar{

go-controller/pkg/ovn/secondary_layer3_network_controller_test.go

@@ -830,7 +830,14 @@ func expectedLayer3EgressEntities(netInfo util.NetInfo, gwConfig util.L3GatewayC
 			ExternalIDs:  standardNonDefaultNetworkExtIDs(netInfo),
 			Nat:          []string{masqSNATUUID1},
 		},
-		&nbdb.LogicalRouterPort{UUID: rtosLRPUUID, Name: rtosLRPName, Networks: []string{"192.168.1.1/24"}, MAC: "0a:58:c0:a8:01:01", GatewayChassis: []string{gatewayChassisUUID}},
+		&nbdb.LogicalRouterPort{
+			UUID:           rtosLRPUUID,
+			Name:           rtosLRPName,
+			Networks:       []string{"192.168.1.1/24"},
+			MAC:            "0a:58:c0:a8:01:01",
+			GatewayChassis: []string{gatewayChassisUUID},
+			Options:        map[string]string{"gateway_mtu": "1400"},
+		},
 		expectedGRStaticRoute(staticRouteUUID1, nodeSubnet.String(), lrsrNextHop, &nbdb.LogicalRouterStaticRoutePolicySrcIP, nil, netInfo),
 		expectedGRStaticRoute(staticRouteUUID2, gwRouterJoinIPAddress().IP.String(), gwRouterJoinIPAddress().IP.String(), nil, nil, netInfo),
 		expectedLogicalRouterPolicy(routerPolicyUUID1, netInfo, nodeName, nodeIP, managementPortIP(nodeSubnet).String()),