changed method for retrieving Windows network statistics

Currently, we are running a Powershell method (Get-NetAdapterStatistics) to retrieve the network statistics in case of awsvpc network mode. However, this can cause CPU spikes on smaller instance types. Therefore, we are switching the method to use native Win32 API for retrieving the same.

GetIfTable2Ex is used for the same. Reference: https://learn.microsoft.com/en-us/windows/win32/api/netioapi/nf-netioapi-getiftable2ex

In this refactor, we have abstracted the details of Win32 API in a new package which is used in Windows workflow.

agent/api/eni/eni.go

@@ -33,6 +33,9 @@ type ENI struct {
 	// LinkName is the name of the ENI on the instance.
 	// Currently, this field is being used only for Windows and is used during task networking setup.
 	LinkName string
+	// InterfaceIndex is the mapping between interface name and index.
+	// Currently, this field is being used only for Windows.
+	InterfaceIndex int
 	// MacAddress is the mac address of the eni
 	MacAddress string
 	// IPV4Addresses is the ipv4 address associated with the eni
@@ -195,8 +198,8 @@ func (eni *ENI) GetHostname() string {
 	return eni.PrivateDNSName
 }
 
-// GetLinkName returns the name of the ENI on the instance.
-func (eni *ENI) GetLinkName() string {
+// GetLinkNameAndIndex returns the name and index of the ENI on the instance.
+func (eni *ENI) GetLinkNameAndIndex() (string, int) {
 	eni.guard.Lock()
 	defer eni.guard.Unlock()
 
@@ -205,24 +208,26 @@ func (eni *ENI) GetLinkName() string {
 		ifaces, err := netInterfaces()
 		if err != nil {
 			seelog.Errorf("Failed to find link name: %v.", err)
-			return ""
+			return "", 0
 		}
 		// Iterate over the list and find the interface with the ENI's MAC address.
 		for _, iface := range ifaces {
 			if strings.EqualFold(eni.MacAddress, iface.HardwareAddr.String()) {
 				eni.LinkName = iface.Name
+				// Additionally, store index in addition to link name.
+				eni.InterfaceIndex = iface.Index
 				break
 			}
 		}
 		// If the ENI is not matched by MAC address above, we will fail to
 		// assign the LinkName. Log that here since CNI will fail with the empty
 		// name.
 		if eni.LinkName == "" {
-			seelog.Errorf("Failed to find LinkName for MAC %s", eni.MacAddress)
+			seelog.Errorf("Failed to find LinkName and index for MAC %s", eni.MacAddress)
 		}
 	}
 
-	return eni.LinkName
+	return eni.LinkName, eni.InterfaceIndex
 }
 
 // IsStandardENI returns true if the ENI is a standard/regular ENI. That is, if it

agent/api/eni/eni_test.go

@@ -32,6 +32,7 @@ const (
 	customSearchDomain = "us-west-2.compute.internal"
 
 	linkName                 = "eth1"
+	linkIndex                = 18
 	macAddr                  = "02:22:ea:8c:81:dc"
 	ipv4Addr                 = "1.2.3.4"
 	ipv4Gw                   = "1.2.3.1"
@@ -70,6 +71,7 @@ var (
 			net.Interface{
 				Name:         linkName,
 				HardwareAddr: parsedMAC,
+				Index:        linkIndex,
 			},
 		}, nil
 	}
@@ -148,26 +150,28 @@ func TestGetSubnetGatewayIPv4Address(t *testing.T) {
 	assert.Equal(t, ipv4Gw, testENI.GetSubnetGatewayIPv4Address())
 }
 
-// TestGetLinkNameSuccess tests the retrieval of ENIs name on the instance.
-func TestGetLinkNameSuccess(t *testing.T) {
+// TestGetLinkNameAndIndexSuccess tests the retrieval of ENIs name and index on the instance.
+func TestGetLinkNameAndIndexSuccess(t *testing.T) {
 	netInterfaces = validNetInterfacesFunc
 	eni := &ENI{
 		MacAddress: macAddr,
 	}
 
-	eniLinkName := eni.GetLinkName()
+	eniLinkName, eniInterfaceIndex := eni.GetLinkNameAndIndex()
 	assert.EqualValues(t, linkName, eniLinkName)
+	assert.EqualValues(t, linkIndex, eniInterfaceIndex)
 }
 
-// TestGetLinkNameFailure tests the retrieval of ENI Name in case of failure.
-func TestGetLinkNameFailure(t *testing.T) {
+// TestGetLinkNameAndIndexFailure tests the retrieval of ENI Name and index in case of failure.
+func TestGetLinkNameAndIndexFailure(t *testing.T) {
 	netInterfaces = invalidNetInterfacesFunc
 	eni := &ENI{
 		MacAddress: macAddr,
 	}
 
-	eniLinkName := eni.GetLinkName()
+	eniLinkName, eniInterfaceIndex := eni.GetLinkNameAndIndex()
 	assert.EqualValues(t, "", eniLinkName)
+	assert.EqualValues(t, 0, eniInterfaceIndex)
 }
 
 func TestENIToString(t *testing.T) {

agent/api/task/task.go

@@ -2780,6 +2780,6 @@ func (task *Task) UpdateTaskENIsLinkName() {
 
 	// Update the link name of the task eni.
 	for _, eni := range task.ENIs {
-		eni.GetLinkName()
+		eni.GetLinkNameAndIndex()
 	}
 }

agent/ecscni/netconfig_windows.go

@@ -50,10 +50,11 @@ func NewVPCENIPluginConfigForTaskNSSetup(eni *eni.ENI, cfg *Config) (*libcni.Net
 			"task network namespace due to failed data validation")
 	}
 
+	linkName, _ := eni.GetLinkNameAndIndex()
 	eniConf := VPCENIPluginConfig{
 		Type:               ECSVPCENIPluginName,
 		DNS:                dns,
-		ENIName:            eni.GetLinkName(),
+		ENIName:            linkName,
 		ENIMACAddress:      eni.MacAddress,
 		ENIIPAddresses:     []string{eni.GetPrimaryIPv4AddressWithPrefixLength()},
 		GatewayIPAddresses: []string{eni.GetSubnetGatewayIPv4Address()},

agent/stats/statsretriever/stats_retriever.go

@@ -0,0 +1,24 @@
+// Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"). You may
+// not use this file except in compliance with the License. A copy of the
+// License is located at
+//
+//	http://aws.amazon.com/apache2.0/
+//
+// or in the "license" file accompanying this file. This file 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 statsretriever
+
+import dockerstats "github.com/docker/docker/api/types"
+
+//go:generate mockgen -destination=mock/$GOFILE -copyright_file=../../../scripts/copyright_file github.com/aws/amazon-ecs-agent/agent/stats/statsretriever StatsRetriever
+
+// StatsRetriever defines methods for retrieving network stats.
+type StatsRetriever interface {
+	// GetNetworkAdapterStatisticsPerContainer returns the network stats for the queried device averaged per container.
+	GetNetworkAdapterStatisticsPerContainer(int, int) (*dockerstats.NetworkStats, error)
+}

agent/stats/statsretriever/stats_retriever_windows.go

@@ -0,0 +1,82 @@
+//go:build windows
+// +build windows
+
+// Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"). You may
+// not use this file except in compliance with the License. A copy of the
+// License is located at
+//
+//	http://aws.amazon.com/apache2.0/
+//
+// or in the "license" file accompanying this file. This file 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 statsretriever
+
+import (
+	"syscall"
+	"unsafe"
+
+	log "github.com/cihub/seelog"
+	dockerstats "github.com/docker/docker/api/types"
+	"github.com/pkg/errors"
+	"golang.org/x/sys/windows"
+)
+
+type retriever struct {
+	// funcGetIfEntry2Ex is the system call for GetIfEntry2Ex Win32 API.
+	funcGetIfEntry2Ex func(a ...uintptr) (r1 uintptr, r2 uintptr, lastErr error)
+}
+
+// NewStatsRetriever returns an instance of StatsRetriever interface.
+func NewStatsRetriever() StatsRetriever {
+	log.Debugf("Initializing stats retriever for Windows")
+	obj := &retriever{}
+
+	// We would be using GetIfEntry2Ex Win32 APIs from IP Helper.
+	moduleIPHelper := windows.NewLazySystemDLL("iphlpapi.dll")
+	procGetIfEntry2Ex := moduleIPHelper.NewProc("GetIfEntry2Ex")
+
+	obj.funcGetIfEntry2Ex = procGetIfEntry2Ex.Call
+	return obj
+}
+
+// GetNetworkAdapterStatisticsPerContainer returns the network stats for the queried device averaged per container.
+func (retriever *retriever) GetNetworkAdapterStatisticsPerContainer(ifIndex int, numberOfContainers int) (*dockerstats.NetworkStats, error) {
+	iface, err := retriever.getIfRowForDevice(ifIndex)
+	if err != nil {
+		return nil, err
+	}
+
+	stats := &dockerstats.NetworkStats{}
+	stats.RxBytes = iface.inOctets / uint64(numberOfContainers)
+	stats.RxPackets = (iface.inNUcastPkts + iface.inUcastPkts) / uint64(numberOfContainers)
+	stats.RxErrors = iface.inErrors / uint64(numberOfContainers)
+	stats.RxDropped = iface.inDiscards / uint64(numberOfContainers)
+	stats.TxBytes = iface.outOctets / uint64(numberOfContainers)
+	stats.TxPackets = (iface.outNUcastPkts + iface.outUcastPkts) / uint64(numberOfContainers)
+	stats.TxErrors = iface.outErrors / uint64(numberOfContainers)
+	stats.TxDropped = iface.outDiscards / uint64(numberOfContainers)
+
+	return stats, nil
+}
+
+// getIfRowForDevice return the MIB_IF_ROW2 object for the queried device.
+// This method would internally invoke the GetIfEntry2Ex Windows API to get the interface row.
+func (retriever *retriever) getIfRowForDevice(ifIndex int) (*mibIfRow2, error) {
+	row := &mibIfRow2{
+		interfaceIndex: uint32(ifIndex),
+	}
+
+	// GetIfEntry2Ex function retrieves the MIB-II interface for the given interface index..
+	// https://learn.microsoft.com/en-us/windows/win32/api/netioapi/nf-netioapi-getifentry2ex
+	retVal, _, _ := retriever.funcGetIfEntry2Ex(uintptr(0), uintptr(unsafe.Pointer(row)))
+	if retVal != 0 {
+		return nil, errors.Errorf("error occured while calling GetIfEntry2Ex: %s", syscall.Errno(retVal))
+	}
+
+	return row, nil
+}

agent/stats/statsretriever/types_windows.go

@@ -0,0 +1,70 @@
+//go:build windows
+// +build windows
+
+// Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"). You may
+// not use this file except in compliance with the License. A copy of the
+// License is located at
+//
+//	http://aws.amazon.com/apache2.0/
+//
+// or in the "license" file accompanying this file. This file 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 statsretriever
+
+import "golang.org/x/sys/windows"
+
+const (
+	ifMaxStringSize        = 256
+	ifMaxPhysAddressLength = 32
+)
+
+// mibIfRow2 structure stores information about a particular interface.
+// https://learn.microsoft.com/en-us/windows/win32/api/netioapi/ns-netioapi-mib_if_row2
+type mibIfRow2 struct {
+	interfaceLUID               uint64
+	interfaceIndex              uint32
+	interfaceGUID               windows.GUID
+	alias                       [ifMaxStringSize + 1]uint16
+	description                 [ifMaxStringSize + 1]uint16
+	physicalAddressLength       uint32
+	physicalAddress             [ifMaxPhysAddressLength]byte
+	permanentPhysicalAddress    [ifMaxPhysAddressLength]byte
+	mtu                         uint32
+	ifType                      uint32
+	tunnelType                  uint32
+	mediaType                   uint32
+	physicalMediumType          uint32
+	accessType                  uint32
+	directionType               uint32
+	interfaceAndOperStatusFlags uint8
+	operStatus                  uint32
+	adminStatus                 uint32
+	mediaConnectState           uint32
+	networkGUID                 windows.GUID
+	connectionType              uint32
+	transmitLinkSpeed           uint64
+	receiveLinkSpeed            uint64
+	inOctets                    uint64
+	inUcastPkts                 uint64
+	inNUcastPkts                uint64
+	inDiscards                  uint64
+	inErrors                    uint64
+	inUnknownProtos             uint64
+	inUcastOctets               uint64
+	inMulticastOctets           uint64
+	inBroadcastOctets           uint64
+	outOctets                   uint64
+	outUcastPkts                uint64
+	outNUcastPkts               uint64
+	outDiscards                 uint64
+	outErrors                   uint64
+	outUcastOctets              uint64
+	outMulticastOctets          uint64
+	outBroadcastOctets          uint64
+	outQLen                     uint64
+}