Set MTU for veths based on VM interface

netio/mocknetio.go

@@ -0,0 +1,46 @@
+package netio
+
+import (
+	"errors"
+	"fmt"
+	"net"
+)
+
+type MockNetIO struct {
+	fail           bool
+	failAttempt    int
+	numTimesCalled int
+}
+
+// ErrMockNetIOFail - mock netio error
+var ErrMockNetIOFail = errors.New("netio fail")
+
+func NewMockNetIO(fail bool, failAttempt int) *MockNetIO {
+	return &MockNetIO{
+		fail:        fail,
+		failAttempt: failAttempt,
+	}
+}
+
+func (netshim *MockNetIO) GetNetworkInterfaceByName(name string) (*net.Interface, error) {
+	netshim.numTimesCalled++
+
+	if netshim.fail && netshim.failAttempt == netshim.numTimesCalled {
+		return nil, fmt.Errorf("%w:%s", ErrMockNetIOFail, name)
+	}
+
+	hwAddr, _ := net.ParseMAC("ab:cd:ef:12:34:56")
+
+	return &net.Interface{
+		//nolint:gomnd // Dummy MTU
+		MTU:          1000,
+		Name:         name,
+		HardwareAddr: hwAddr,
+		//nolint:gomnd // Dummy interface index
+		Index: 2,
+	}, nil
+}
+
+func (netshim *MockNetIO) GetNetworkInterfaceAddrs(iface *net.Interface) ([]net.Addr, error) {
+	return []net.Addr{}, nil
+}

netio/netio.go

@@ -0,0 +1,32 @@
+package netio
+
+import (
+	"net"
+
+	"github.com/pkg/errors"
+)
+
+//nolint:revive // keeping NetIOInterface makes sense
+type NetIOInterface interface {
+	GetNetworkInterfaceByName(name string) (*net.Interface, error)
+	GetNetworkInterfaceAddrs(iface *net.Interface) ([]net.Addr, error)
+}
+
+// ErrInterfaceNil - errors out when interface is nil
+var ErrInterfaceNil = errors.New("Interface is nil")
+
+type NetIO struct{}
+
+func (ns *NetIO) GetNetworkInterfaceByName(name string) (*net.Interface, error) {
+	iface, err := net.InterfaceByName(name)
+	return iface, errors.Wrap(err, "GetNetworkInterfaceByName failed")
+}
+
+func (ns *NetIO) GetNetworkInterfaceAddrs(iface *net.Interface) ([]net.Addr, error) {
+	if iface == nil {
+		return []net.Addr{}, ErrInterfaceNil
+	}
+
+	addrs, err := iface.Addrs()
+	return addrs, errors.Wrap(err, "GetNetworkInterfaceAddrs failed")
+}

netlink/link.go

@@ -11,6 +11,7 @@ import (
 	"net"
 
 	"github.com/Azure/azure-container-networking/log"
+	"github.com/pkg/errors"
 	"golang.org/x/sys/unix"
 )
 
@@ -151,6 +152,29 @@ func (Netlink) AddLink(link Link) error {
 	return s.sendAndWaitForAck(req)
 }
 
+func (Netlink) SetLinkMTU(name string, mtu int) error {
+	iface, err := net.InterfaceByName(name)
+	if err != nil {
+		log.Printf("[net] Interface not found. returning error")
+		return errors.Wrap(err, "SetLinkMTU:InterfaceByName failed")
+	}
+
+	s, err := getSocket()
+	if err != nil {
+		return err
+	}
+
+	req := newRequest(unix.RTM_SETLINK, unix.NLM_F_ACK)
+	ifInfo := newIfInfoMsg()
+	ifInfo.Index = int32(iface.Index)
+	req.addPayload(ifInfo)
+
+	mtuData := newAttributeUint32(unix.IFLA_MTU, uint32(mtu))
+	req.addPayload(mtuData)
+
+	return s.sendAndWaitForAck(req)
+}
+
 // DeleteLink deletes a network interface.
 func (Netlink) DeleteLink(name string) error {
 	if name == "" {

netlink/mocknetlink.go

@@ -6,19 +6,20 @@ import (
 	"net"
 )
 
-var errorMockNetlink = errors.New("Mock Netlink Error")
+// ErrorMockNetlink - netlink mock error
+var ErrorMockNetlink = errors.New("Mock Netlink Error")
 
 func newErrorMockNetlink(errStr string) error {
-	return fmt.Errorf("%w : %s", errorMockNetlink, errStr)
+	return fmt.Errorf("%w : %s", ErrorMockNetlink, errStr)
 }
 
 type MockNetlink struct {
 	returnError bool
 	errorString string
 }
 
-func NewMockNetlink(returnError bool, errorString string) MockNetlink {
-	return MockNetlink{
+func NewMockNetlink(returnError bool, errorString string) *MockNetlink {
+	return &MockNetlink{
 		returnError: returnError,
 		errorString: errorString,
 	}
@@ -31,11 +32,15 @@ func (f *MockNetlink) error() error {
 	return nil
 }
 
-func (f *MockNetlink) AddLink(Link) error {
+func (f *MockNetlink) AddLink(l Link) error {
 	return f.error()
 }
 
-func (f *MockNetlink) DeleteLink(string) error {
+func (f *MockNetlink) SetLinkMTU(name string, mtu int) error {
+	return f.error()
+}
+
+func (f *MockNetlink) DeleteLink(name string) error {
 	return f.error()
 }
 

netlink/netlink_test.go

@@ -9,6 +9,8 @@ package netlink
 import (
 	"net"
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 const (
@@ -99,6 +101,37 @@ func TestAddDeleteVEth(t *testing.T) {
 	}
 }
 
+// TestSetMTU tests if MTU can be sent on link
+func TestSetMTU(t *testing.T) {
+	link := VEthLink{
+		LinkInfo: LinkInfo{
+			Type: LINK_TYPE_VETH,
+			Name: ifName,
+		},
+		PeerName: ifName2,
+	}
+	nl := NewNetlink()
+
+	err := nl.AddLink(&link)
+	if err != nil {
+		t.Errorf("AddLink failed: %+v", err)
+	}
+
+	//nolint:errcheck // not testing deletelink here
+	defer nl.DeleteLink(ifName)
+
+	if err = nl.SetLinkMTU(ifName, 1028); err != nil {
+		t.Errorf("SetMTU failed: %+v", err)
+	}
+
+	iface, err := net.InterfaceByName(ifName)
+	if err != nil {
+		t.Errorf("InterfaceByName err:%v", err)
+	}
+
+	require.Equal(t, 1028, iface.MTU, "Expected mtu:1024 but got %d", iface.MTU)
+}
+
 // TestAddDeleteIPVlan tests adding and deleting an IPVLAN interface.
 func TestAddDeleteIPVlan(t *testing.T) {
 	dummy, err := addDummyInterface(dummyName)

netlink/netlink_windows.go

@@ -26,6 +26,10 @@ func (Netlink) AddLink(link Link) error {
 	return nil
 }
 
+func (Netlink) SetLinkMTU(name string, mtu int) error {
+	return nil
+}
+
 func (Netlink) DeleteLink(name string) error {
 	return nil
 }

network/netlinkinterface/netlinkinterface.go → netlink/netlinkinterface.go

@@ -1,19 +1,18 @@
 // Copyright 2021 Microsoft. All rights reserved.
 // MIT License
 
-package netlinkinterface
+package netlink
 
 import (
 	"net"
-
-	"github.com/Azure/azure-container-networking/netlink"
 )
 
 type NetlinkInterface interface {
-	AddLink(link netlink.Link) error
+	AddLink(link Link) error
 	DeleteLink(name string) error
 	SetLinkName(name string, newName string) error
 	SetLinkState(name string, up bool) error
+	SetLinkMTU(name string, mtu int) error
 	SetLinkMaster(name string, master string) error
 	SetLinkNetNs(name string, fd uintptr) error
 	SetLinkAddress(ifName string, hwAddress net.HardwareAddr) error
@@ -22,7 +21,7 @@ type NetlinkInterface interface {
 	AddOrRemoveStaticArp(mode int, name string, ipaddr net.IP, mac net.HardwareAddr, isProxy bool) error
 	AddIPAddress(ifName string, ipAddress net.IP, ipNet *net.IPNet) error
 	DeleteIPAddress(ifName string, ipAddress net.IP, ipNet *net.IPNet) error
-	GetIPRoute(filter *netlink.Route) ([]*netlink.Route, error)
-	AddIPRoute(route *netlink.Route) error
-	DeleteIPRoute(route *netlink.Route) error
+	GetIPRoute(filter *Route) ([]*Route, error)
+	AddIPRoute(route *Route) error
+	DeleteIPRoute(route *Route) error
 }

network/bridge_endpointclient_linux.go

@@ -8,7 +8,6 @@ import (
 	"github.com/Azure/azure-container-networking/log"
 	"github.com/Azure/azure-container-networking/netlink"
 	"github.com/Azure/azure-container-networking/network/epcommon"
-	"github.com/Azure/azure-container-networking/network/netlinkinterface"
 )
 
 const (
@@ -26,15 +25,15 @@ type LinuxBridgeEndpointClient struct {
 	containerMac      net.HardwareAddr
 	hostIPAddresses   []*net.IPNet
 	mode              string
-	netlink           netlinkinterface.NetlinkInterface
+	netlink           netlink.NetlinkInterface
 }
 
 func NewLinuxBridgeEndpointClient(
 	extIf *externalInterface,
 	hostVethName string,
 	containerVethName string,
 	mode string,
-	nl netlinkinterface.NetlinkInterface,
+	nl netlink.NetlinkInterface,
 ) *LinuxBridgeEndpointClient {
 
 	client := &LinuxBridgeEndpointClient{

network/bridge_networkclient_linux.go

@@ -9,7 +9,6 @@ import (
 	"github.com/Azure/azure-container-networking/log"
 	"github.com/Azure/azure-container-networking/netlink"
 	"github.com/Azure/azure-container-networking/network/epcommon"
-	"github.com/Azure/azure-container-networking/network/netlinkinterface"
 )
 
 const (
@@ -26,14 +25,14 @@ type LinuxBridgeClient struct {
 	bridgeName        string
 	hostInterfaceName string
 	nwInfo            NetworkInfo
-	netlink           netlinkinterface.NetlinkInterface
+	netlink           netlink.NetlinkInterface
 }
 
 func NewLinuxBridgeClient(
 	bridgeName string,
 	hostInterfaceName string,
 	nwInfo NetworkInfo,
-	nl netlinkinterface.NetlinkInterface,
+	nl netlink.NetlinkInterface,
 ) *LinuxBridgeClient {
 	client := &LinuxBridgeClient{
 		bridgeName:        bridgeName,

network/endpoint.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 
 	"github.com/Azure/azure-container-networking/log"
-	"github.com/Azure/azure-container-networking/network/netlinkinterface"
+	"github.com/Azure/azure-container-networking/netlink"
 	"github.com/Azure/azure-container-networking/network/policy"
 )
 
@@ -98,7 +98,7 @@ type apipaClient interface {
 }
 
 // NewEndpoint creates a new endpoint in the network.
-func (nw *network) newEndpoint(cli apipaClient, nl netlinkinterface.NetlinkInterface, epInfo *EndpointInfo) (*endpoint, error) {
+func (nw *network) newEndpoint(cli apipaClient, nl netlink.NetlinkInterface, epInfo *EndpointInfo) (*endpoint, error) {
 	var ep *endpoint
 	var err error
 
@@ -122,7 +122,7 @@ func (nw *network) newEndpoint(cli apipaClient, nl netlinkinterface.NetlinkInter
 }
 
 // DeleteEndpoint deletes an existing endpoint from the network.
-func (nw *network) deleteEndpoint(cli apipaClient, nl netlinkinterface.NetlinkInterface, endpointID string) error {
+func (nw *network) deleteEndpoint(cli apipaClient, nl netlink.NetlinkInterface, endpointID string) error {
 	var err error
 
 	log.Printf("[net] Deleting endpoint %v from network %v.", endpointID, nw.Id)

network/endpoint_linux.go

@@ -12,7 +12,6 @@ import (
 
 	"github.com/Azure/azure-container-networking/log"
 	"github.com/Azure/azure-container-networking/netlink"
-	"github.com/Azure/azure-container-networking/network/netlinkinterface"
 	"github.com/Azure/azure-container-networking/ovsctl"
 )
 
@@ -46,7 +45,7 @@ func ConstructEndpointID(containerID string, _ string, ifName string) (string, s
 }
 
 // newEndpointImpl creates a new endpoint in the network.
-func (nw *network) newEndpointImpl(_ apipaClient, nl netlinkinterface.NetlinkInterface, epInfo *EndpointInfo) (*endpoint, error) {
+func (nw *network) newEndpointImpl(_ apipaClient, nl netlink.NetlinkInterface, epInfo *EndpointInfo) (*endpoint, error) {
 	var containerIf *net.Interface
 	var ns *Namespace
 	var ep *endpoint
@@ -219,7 +218,7 @@ func (nw *network) newEndpointImpl(_ apipaClient, nl netlinkinterface.NetlinkInt
 }
 
 // deleteEndpointImpl deletes an existing endpoint from the network.
-func (nw *network) deleteEndpointImpl(_ apipaClient, nl netlinkinterface.NetlinkInterface, ep *endpoint) error {
+func (nw *network) deleteEndpointImpl(_ apipaClient, nl netlink.NetlinkInterface, ep *endpoint) error {
 	var epClient EndpointClient
 
 	// Delete the veth pair by deleting one of the peer interfaces.
@@ -244,7 +243,7 @@ func (nw *network) deleteEndpointImpl(_ apipaClient, nl netlinkinterface.Netlink
 func (ep *endpoint) getInfoImpl(epInfo *EndpointInfo) {
 }
 
-func addRoutes(nl netlinkinterface.NetlinkInterface, interfaceName string, routes []RouteInfo) error {
+func addRoutes(nl netlink.NetlinkInterface, interfaceName string, routes []RouteInfo) error {
 	ifIndex := 0
 	interfaceIf, _ := net.InterfaceByName(interfaceName)
 
@@ -285,7 +284,7 @@ func addRoutes(nl netlinkinterface.NetlinkInterface, interfaceName string, route
 	return nil
 }
 
-func deleteRoutes(nl netlinkinterface.NetlinkInterface, interfaceName string, routes []RouteInfo) error {
+func deleteRoutes(nl netlink.NetlinkInterface, interfaceName string, routes []RouteInfo) error {
 	ifIndex := 0
 	interfaceIf, _ := net.InterfaceByName(interfaceName)