Change maximum number of buckets in an OVS group add/insert_bucket me…

…ssage

The current implementation limits the maximum number of buckets in an OVS group
add/insert_bucket message to 800. This constraint is based on the fact that each
bucket has 3 actions, such as `set_field:0xa0a0007->reg0`,
`set_field:0x50/0xffff->reg4`, and `resubmit(,EndpointDNAT)`. However, an update
in antrea-io#5205 introduced a new action, `set_field:0x4000000/0x4000000->reg4`, for
remote Endpoints, making it impossible to accommodate 800 buckets with 4 actions
in an OVS group add/insert_bucket message.

To overcome the limitation, we set the maximum number of buckets to 700, considering
the worst-case scenario where each bucket includes all available actions. For example,
a bucket with all available actions, which is for a remote non-hostNetwork IPv6 Service
Endpoint like this: `set_field:0xa0a0007->xxreg0`, `set_field:0x50/0xffff->reg4`,
`set_field:0x100000/0x100000->reg4`, and `resubmit(,EndpointDNAT)`. The size of such
bucket is 88 bytes, and the header size of an OVS group message is 24 bytes.
According to https://opennetworking.org/wp-content/uploads/2014/10/openflow-switch-v1.5.1.pdf,
the max size of an Openflow 1.5 message is 64000 bytes, as a result, a message can have
a maximum of 727 buckets with the largest size.

Signed-off-by: Hongliang Liu <[email protected]>

pkg/agent/openflow/client_test.go

@@ -22,6 +22,7 @@ import (
 	"sync/atomic"
 	"testing"
 	"time"
+	"unsafe"
 
 	"antrea.io/libOpenflow/openflow15"
 	"antrea.io/libOpenflow/protocol"
@@ -47,6 +48,8 @@ import (
 
 const bridgeName = "dummy-br"
 
+const openflowMessageMaxSize = 64000
+
 var (
 	bridgeMgmtAddr = binding.GetMgmtAddress(ovsconfig.DefaultOVSRunDir, bridgeName)
 
@@ -1123,6 +1126,73 @@ func Test_client_InstallServiceGroup(t *testing.T) {
 	}
 }
 
+func getServiceBucketMaxSize(t *testing.T, ctrl *gomock.Controller) uint16 {
+	fakeOfTable := ovsoftest.NewMockTable(ctrl)
+	fakeNodeIPChecker := nodeiptest.NewFakeNodeIPChecker("2001::2")
+	ServiceLBTable.ofTable = fakeOfTable
+	defer func() {
+		ServiceLBTable.ofTable = nil
+	}()
+	fs := &featureService{
+		groupCache:    sync.Map{},
+		bridge:        binding.NewOFBridge(bridgeName, ""),
+		nodeIPChecker: fakeNodeIPChecker,
+	}
+	// To create a single-bucket group with maximum size, use a remote non-hostNetwork IPv6 Endpoint that has all
+	// available actions.
+	endpoint := proxy.NewBaseEndpointInfo("2001::1", "node1", "", 80, false, true, false, false, nil)
+	fakeOfTable.EXPECT().GetID().Return(uint8(1)).Times(1)
+	group := fs.serviceEndpointGroup(binding.GroupIDType(100), true, endpoint)
+
+	messages, err := group.GetBundleMessages(binding.AddMessage)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(messages))
+	groupMod := messages[0].GetMessage().(*openflow15.GroupMod)
+	require.Equal(t, 1, len(groupMod.Buckets))
+	// Since this is a single-bucket group, the `BucketArrayLen` is the size of the bucket.
+	t.Logf("The maxinum size of a Service group bucket is %d bytes", groupMod.BucketArrayLen)
+	return groupMod.BucketArrayLen
+}
+
+func getMulticastBucketMaxSize(t *testing.T, ctrl *gomock.Controller) uint16 {
+	fs := &featureMulticast{
+		groupCache: sync.Map{},
+		bridge:     binding.NewOFBridge(bridgeName, ""),
+	}
+	fakeOfTable := ovsoftest.NewMockTable(ctrl)
+	MulticastOutputTable.ofTable = fakeOfTable
+	defer func() {
+		MulticastOutputTable.ofTable = nil
+	}()
+
+	// Create a single-bucket group with maximum size.
+	fakeOfTable.EXPECT().GetID().Return(uint8(1)).Times(1)
+	group := fs.multicastReceiversGroup(binding.GroupIDType(100), 0, nil, []net.IP{net.ParseIP("192.168.77.100")})
+
+	messages, err := group.GetBundleMessages(binding.AddMessage)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(messages))
+	groupMod := messages[0].GetMessage().(*openflow15.GroupMod)
+	require.Equal(t, 1, len(groupMod.Buckets))
+	// Since this is a single-bucket group, the `BucketArrayLen` is the size of the bucket.
+	t.Logf("The maxinum size of a Multicast group bucket is %d bytes", groupMod.BucketArrayLen)
+	return groupMod.BucketArrayLen
+}
+
+func TestMaxBucketsPerMessage(t *testing.T) {
+	ctrl := gomock.NewController(t)
+
+	groupModHeaderSize := uint16(unsafe.Sizeof(openflow15.GroupMod{}) - unsafe.Sizeof(openflow15.GroupMod{}.Buckets) - unsafe.Sizeof(openflow15.GroupMod{}.Properties))
+	serviceMaxBucketsPerMessage := int((openflowMessageMaxSize - groupModHeaderSize) / getServiceBucketMaxSize(t, ctrl))
+	t.Logf("Maximum buckets in a Service group: %d\n", serviceMaxBucketsPerMessage)
+	multicastMaxBucketsPerMessage := int((openflowMessageMaxSize - groupModHeaderSize) / getMulticastBucketMaxSize(t, ctrl))
+	t.Logf("Maximum buckets in a Multicast group: %d\n", multicastMaxBucketsPerMessage)
+
+	// Ensure that binding.MaxBucketsPerMessage is less than or equal to every feature's maximum supported buckets.
+	require.LessOrEqual(t, binding.MaxBucketsPerMessage, serviceMaxBucketsPerMessage)
+	require.LessOrEqual(t, binding.MaxBucketsPerMessage, multicastMaxBucketsPerMessage)
+}
+
 func Test_client_InstallEndpointFlows(t *testing.T) {
 	ep1IPv4 := "10.10.0.100"
 	ep2IPv4 := "10.10.0.101"

pkg/ovs/openflow/ofctrl_group.go

@@ -24,7 +24,7 @@ import (
 )
 
 var (
-	MaxBucketsPerMessage = 800
+	MaxBucketsPerMessage = 700
 )
 
 type ofGroup struct {