Revert "Revert "syncNetworkUtil in kubelet and fix loadbalancerSourceRange on GCE""

cmd/kube-proxy/app/server.go

@@ -204,8 +204,7 @@ func NewProxyServerDefault(config *options.ProxyServerConfig) (*ProxyServer, err
 			// IPTablesMasqueradeBit must be specified or defaulted.
 			return nil, fmt.Errorf("Unable to read IPTablesMasqueradeBit from config")
 		}
-
-		proxierIptables, err := iptables.NewProxier(iptInterface, execer, config.IPTablesSyncPeriod.Duration, config.MasqueradeAll, int(*config.IPTablesMasqueradeBit), config.ClusterCIDR, hostname)
+		proxierIptables, err := iptables.NewProxier(iptInterface, execer, config.IPTablesSyncPeriod.Duration, config.MasqueradeAll, int(*config.IPTablesMasqueradeBit), config.ClusterCIDR, hostname, getNodeIP(client, hostname))
 		if err != nil {
 			glog.Fatalf("Unable to create proxier: %v", err)
 		}
@@ -409,3 +408,18 @@ func tryIptablesProxy(iptver iptables.IptablesVersioner, kcompat iptables.Kernel
 func (s *ProxyServer) birthCry() {
 	s.Recorder.Eventf(s.Config.NodeRef, api.EventTypeNormal, "Starting", "Starting kube-proxy.")
 }
+
+func getNodeIP(client *kubeclient.Client, hostname string) net.IP {
+	var nodeIP net.IP
+	node, err := client.Nodes().Get(hostname)
+	if err != nil {
+		glog.Warningf("Failed to retrieve node info: %v", err)
+		return nil
+	}
+	nodeIP, err = nodeutil.GetNodeHostIP(node)
+	if err != nil {
+		glog.Warningf("Failed to retrieve node IP: %v", err)
+		return nil
+	}
+	return nodeIP
+}

cmd/kubelet/app/options/options.go

@@ -172,6 +172,9 @@ func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
 	fs.StringVar(&s.ResolverConfig, "resolv-conf", s.ResolverConfig, "Resolver configuration file used as the basis for the container DNS resolution configuration.")
 	fs.BoolVar(&s.CPUCFSQuota, "cpu-cfs-quota", s.CPUCFSQuota, "Enable CPU CFS quota enforcement for containers that specify CPU limits")
 	fs.BoolVar(&s.EnableControllerAttachDetach, "enable-controller-attach-detach", s.EnableControllerAttachDetach, "Enables the Attach/Detach controller to manage attachment/detachment of volumes scheduled to this node, and disables kubelet from executing any attach/detach operations")
+	fs.BoolVar(&s.MakeIPTablesUtilChains, "make-iptables-util-chains", s.MakeIPTablesUtilChains, "If true, kubelet will ensure iptables utility rules are present on host.")
+	fs.Int32Var(&s.IPTablesMasqueradeBit, "iptables-masquerade-bit", s.IPTablesMasqueradeBit, "The bit of the fwmark space to mark packets for SNAT. Must be within the range [0, 31]. Please match this parameter with corresponding parameter in kube-proxy.")
+	fs.Int32Var(&s.IPTablesDropBit, "iptables-drop-bit", s.IPTablesDropBit, "The bit of the fwmark space to mark packets for dropping. Must be within the range [0, 31].")
 
 	// Flags intended for testing, not recommended used in production environments.
 	fs.BoolVar(&s.ReallyCrashForTesting, "really-crash-for-testing", s.ReallyCrashForTesting, "If true, when panics occur crash. Intended for testing.")

cmd/kubelet/app/server.go

@@ -200,6 +200,18 @@ func UnsecuredKubeletConfig(s *options.KubeletServer) (*KubeletConfig, error) {
 		Thresholds:               thresholds,
 	}
 
+	if s.MakeIPTablesUtilChains {
+		if s.IPTablesMasqueradeBit > 31 || s.IPTablesMasqueradeBit < 0 {
+			return nil, fmt.Errorf("iptables-masquerade-bit is not valid. Must be within [0, 31]")
+		}
+		if s.IPTablesDropBit > 31 || s.IPTablesDropBit < 0 {
+			return nil, fmt.Errorf("iptables-drop-bit is not valid. Must be within [0, 31]")
+		}
+		if s.IPTablesDropBit == s.IPTablesMasqueradeBit {
+			return nil, fmt.Errorf("iptables-masquerade-bit and iptables-drop-bit must be different")
+		}
+	}
+
 	return &KubeletConfig{
 		Address:                      net.ParseIP(s.Address),
 		AllowPrivileged:              s.AllowPrivileged,
@@ -286,6 +298,9 @@ func UnsecuredKubeletConfig(s *options.KubeletServer) (*KubeletConfig, error) {
 		EvictionConfig:         evictionConfig,
 		PodsPerCore:            int(s.PodsPerCore),
 		ProtectKernelDefaults:  s.ProtectKernelDefaults,
+		MakeIPTablesUtilChains: s.MakeIPTablesUtilChains,
+		iptablesMasqueradeBit:  int(s.IPTablesMasqueradeBit),
+		iptablesDropBit:        int(s.IPTablesDropBit),
 	}, nil
 }
 
@@ -917,8 +932,10 @@ type KubeletConfig struct {
 	HairpinMode                string
 	BabysitDaemons             bool
 	Options                    []kubelet.Option
-
 	ProtectKernelDefaults      bool
+	MakeIPTablesUtilChains     bool
+	iptablesMasqueradeBit      int
+	iptablesDropBit            int
 }
 
 func CreateAndInitKubelet(kc *KubeletConfig) (k KubeletBootstrap, pc *config.PodConfig, err error) {
@@ -1016,6 +1033,9 @@ func CreateAndInitKubelet(kc *KubeletConfig) (k KubeletBootstrap, pc *config.Pod
 		kc.EvictionConfig,
 		kc.Options,
 		kc.EnableControllerAttachDetach,
+		kc.MakeIPTablesUtilChains,
+		kc.iptablesMasqueradeBit,
+		kc.iptablesDropBit,
 	)
 
 	if err != nil {

hack/verify-flags/known-flags.txt

@@ -230,6 +230,7 @@ insecure-port
 insecure-skip-tls-verify
 instance-metadata
 instance-name-prefix
+iptables-drop-bit
 iptables-masquerade-bit
 iptables-sync-period
 ir-data-source
@@ -289,6 +290,7 @@ lock-file
 log-flush-frequency
 long-running-request-regexp
 low-diskspace-threshold-mb
+make-iptables-util-chains
 make-symlinks
 manifest-path
 manifest-url

pkg/apis/componentconfig/types.go

@@ -399,6 +399,18 @@ type KubeletConfiguration struct {
 	KubeReserved utilconfig.ConfigurationMap `json:"kubeReserved"`
 	// Default behaviour for kernel tuning
 	ProtectKernelDefaults bool `json:"protectKernelDefaults"`
+	// If true, Kubelet ensures a set of iptables rules are present on host.
+	// These rules will serve as utility for various components, e.g. kube-proxy.
+	// The rules will be created based on IPTablesMasqueradeBit and IPTablesDropBit.
+	MakeIPTablesUtilChains bool `json:"makeIPTablesUtilChains"`
+	// iptablesMasqueradeBit is the bit of the iptables fwmark space to use for SNAT
+	// Values must be within the range [0, 31].
+	// Warning: Please match the value of corresponding parameter in kube-proxy
+	// TODO: clean up IPTablesMasqueradeBit in kube-proxy
+	IPTablesMasqueradeBit int32 `json:"iptablesMasqueradeBit"`
+	// iptablesDropBit is the bit of the iptables fwmark space to use for dropping packets. Kubelet will ensure iptables mark and drop rules.
+	// Values must be within the range [0, 31]. Must be different from IPTablesMasqueradeBit
+	IPTablesDropBit int32 `json:"iptablesDropBit"`
 }
 
 type KubeSchedulerConfiguration struct {

pkg/apis/componentconfig/v1alpha1/defaults.go

@@ -43,6 +43,9 @@ const (
 	defaultRktAPIServiceEndpoint = "localhost:15441"
 
 	AutoDetectCloudProvider = "auto-detect"
+
+	defaultIPTablesMasqueradeBit = 14
+	defaultIPTablesDropBit       = 15
 )
 
 var zeroDuration = unversioned.Duration{}
@@ -337,6 +340,17 @@ func SetDefaults_KubeletConfiguration(obj *KubeletConfiguration) {
 	if obj.KubeReserved == nil {
 		obj.KubeReserved = make(map[string]string)
 	}
+	if obj.MakeIPTablesUtilChains == nil {
+		obj.MakeIPTablesUtilChains = boolVar(true)
+	}
+	if obj.IPTablesMasqueradeBit == nil {
+		temp := int32(defaultIPTablesMasqueradeBit)
+		obj.IPTablesMasqueradeBit = &temp
+	}
+	if obj.IPTablesDropBit == nil {
+		temp := int32(defaultIPTablesDropBit)
+		obj.IPTablesDropBit = &temp
+	}
 }
 
 func boolVar(b bool) *bool {

pkg/apis/componentconfig/v1alpha1/types.go

@@ -454,4 +454,16 @@ type KubeletConfiguration struct {
 	KubeReserved map[string]string `json:"kubeReserved"`
 	// Default behaviour for kernel tuning
 	ProtectKernelDefaults bool `json:"protectKernelDefaults"`
+	// If true, Kubelet ensures a set of iptables rules are present on host.
+	// These rules will serve as utility rules for various components, e.g. KubeProxy.
+	// The rules will be created based on IPTablesMasqueradeBit and IPTablesDropBit.
+	MakeIPTablesUtilChains *bool `json:"makeIPTablesUtilChains"`
+	// iptablesMasqueradeBit is the bit of the iptables fwmark space to mark for SNAT
+	// Values must be within the range [0, 31]. Must be different from other mark bits.
+	// Warning: Please match the value of corresponding parameter in kube-proxy
+	// TODO: clean up IPTablesMasqueradeBit in kube-proxy
+	IPTablesMasqueradeBit *int32 `json:"iptablesMasqueradeBit"`
+	// iptablesDropBit is the bit of the iptables fwmark space to mark for dropping packets.
+	// Values must be within the range [0, 31]. Must be different from other mark bits.
+	IPTablesDropBit *int32 `json:"iptablesDropBit"`
 }

pkg/apis/componentconfig/v1alpha1/zz_generated.conversion.go

@@ -320,6 +320,15 @@ func autoConvert_v1alpha1_KubeletConfiguration_To_componentconfig_KubeletConfigu
 		out.KubeReserved = nil
 	}
 	out.ProtectKernelDefaults = in.ProtectKernelDefaults
+	if err := api.Convert_Pointer_bool_To_bool(&in.MakeIPTablesUtilChains, &out.MakeIPTablesUtilChains, s); err != nil {
+		return err
+	}
+	if err := api.Convert_Pointer_int32_To_int32(&in.IPTablesMasqueradeBit, &out.IPTablesMasqueradeBit, s); err != nil {
+		return err
+	}
+	if err := api.Convert_Pointer_int32_To_int32(&in.IPTablesDropBit, &out.IPTablesDropBit, s); err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -485,6 +494,15 @@ func autoConvert_componentconfig_KubeletConfiguration_To_v1alpha1_KubeletConfigu
 		out.KubeReserved = nil
 	}
 	out.ProtectKernelDefaults = in.ProtectKernelDefaults
+	if err := api.Convert_bool_To_Pointer_bool(&in.MakeIPTablesUtilChains, &out.MakeIPTablesUtilChains, s); err != nil {
+		return err
+	}
+	if err := api.Convert_int32_To_Pointer_int32(&in.IPTablesMasqueradeBit, &out.IPTablesMasqueradeBit, s); err != nil {
+		return err
+	}
+	if err := api.Convert_int32_To_Pointer_int32(&in.IPTablesDropBit, &out.IPTablesDropBit, s); err != nil {
+		return err
+	}
 	return nil
 }
 

pkg/apis/componentconfig/v1alpha1/zz_generated.deepcopy.go

@@ -378,6 +378,27 @@ func DeepCopy_v1alpha1_KubeletConfiguration(in interface{}, out interface{}, c *
 			out.KubeReserved = nil
 		}
 		out.ProtectKernelDefaults = in.ProtectKernelDefaults
+		if in.MakeIPTablesUtilChains != nil {
+			in, out := &in.MakeIPTablesUtilChains, &out.MakeIPTablesUtilChains
+			*out = new(bool)
+			**out = **in
+		} else {
+			out.MakeIPTablesUtilChains = nil
+		}
+		if in.IPTablesMasqueradeBit != nil {
+			in, out := &in.IPTablesMasqueradeBit, &out.IPTablesMasqueradeBit
+			*out = new(int32)
+			**out = **in
+		} else {
+			out.IPTablesMasqueradeBit = nil
+		}
+		if in.IPTablesDropBit != nil {
+			in, out := &in.IPTablesDropBit, &out.IPTablesDropBit
+			*out = new(int32)
+			**out = **in
+		} else {
+			out.IPTablesDropBit = nil
+		}
 		return nil
 	}
 }

pkg/apis/componentconfig/zz_generated.deepcopy.go

@@ -330,6 +330,9 @@ func DeepCopy_componentconfig_KubeletConfiguration(in interface{}, out interface
 			out.KubeReserved = nil
 		}
 		out.ProtectKernelDefaults = in.ProtectKernelDefaults
+		out.MakeIPTablesUtilChains = in.MakeIPTablesUtilChains
+		out.IPTablesMasqueradeBit = in.IPTablesMasqueradeBit
+		out.IPTablesDropBit = in.IPTablesDropBit
 		return nil
 	}
 }

pkg/kubelet/kubelet.go

@@ -244,6 +244,9 @@ func NewMainKubelet(
 	evictionConfig eviction.Config,
 	kubeOptions []Option,
 	enableControllerAttachDetach bool,
+	makeIPTablesUtilChains bool,
+	iptablesMasqueradeBit int,
+	iptablesDropBit int,
 ) (*Kubelet, error) {
 	if rootDirectory == "" {
 		return nil, fmt.Errorf("invalid root directory %q", rootDirectory)
@@ -368,6 +371,9 @@ func NewMainKubelet(
 		babysitDaemons:               babysitDaemons,
 		enableControllerAttachDetach: enableControllerAttachDetach,
 		iptClient:                    utilipt.New(utilexec.New(), utildbus.New(), utilipt.ProtocolIpv4),
+		makeIPTablesUtilChains:       makeIPTablesUtilChains,
+		iptablesMasqueradeBit:        iptablesMasqueradeBit,
+		iptablesDropBit:              iptablesDropBit,
 	}
 
 	if klet.flannelExperimentalOverlay {
@@ -845,6 +851,15 @@ type Kubelet struct {
 
 	// trigger deleting containers in a pod
 	containerDeletor *podContainerDeletor
+
+	// config iptables util rules
+	makeIPTablesUtilChains bool
+
+	// The bit of the fwmark space to mark packets for SNAT.
+	iptablesMasqueradeBit int
+
+	// The bit of the fwmark space to mark packets for dropping.
+	iptablesDropBit int
 }
 
 // setupDataDirs creates:
@@ -971,6 +986,11 @@ func (kl *Kubelet) Run(updates <-chan kubetypes.PodUpdate) {
 	go wait.Until(kl.syncNetworkStatus, 30*time.Second, wait.NeverStop)
 	go wait.Until(kl.updateRuntimeUp, 5*time.Second, wait.NeverStop)
 
+	// Start loop to sync iptables util rules
+	if kl.makeIPTablesUtilChains {
+		go wait.Until(kl.syncNetworkUtil, 1*time.Minute, wait.NeverStop)
+	}
+
 	// Start a goroutine responsible for killing pods (that are not properly
 	// handled by pod workers).
 	go wait.Until(kl.podKiller, 1*time.Second, wait.NeverStop)

pkg/kubelet/kubelet_network.go

@@ -28,9 +28,25 @@ import (
 	"k8s.io/kubernetes/pkg/apis/componentconfig"
 	"k8s.io/kubernetes/pkg/kubelet/network"
 	"k8s.io/kubernetes/pkg/util/bandwidth"
+	utiliptables "k8s.io/kubernetes/pkg/util/iptables"
 	"k8s.io/kubernetes/pkg/util/sets"
 )
 
+const (
+	// the mark-for-masquerade chain
+	// TODO: clean up this logic in kube-proxy
+	KubeMarkMasqChain utiliptables.Chain = "KUBE-MARK-MASQ"
+
+	// the mark-for-drop chain
+	KubeMarkDropChain utiliptables.Chain = "KUBE-MARK-DROP"
+
+	// kubernetes postrouting rules
+	KubePostroutingChain utiliptables.Chain = "KUBE-POSTROUTING"
+
+	// kubernetes postrouting rules
+	KubeFirewallChain utiliptables.Chain = "KUBE-FIREWALL"
+)
+
 // effectiveHairpinMode determines the effective hairpin mode given the
 // configured mode, container runtime, and whether cbr0 should be configured.
 func effectiveHairpinMode(hairpinMode componentconfig.HairpinMode, containerRuntime string, configureCBR0 bool, networkPlugin string) (componentconfig.HairpinMode, error) {
@@ -303,3 +319,88 @@ func (kl *Kubelet) shapingEnabled() bool {
 	}
 	return true
 }
+
+// syncNetworkUtil ensures the network utility are present on host.
+// Network util includes:
+// 1. 	In nat table, KUBE-MARK-DROP rule to mark connections for dropping
+// 	Marked connection will be drop on INPUT/OUTPUT Chain in filter table
+// 2. 	In nat table, KUBE-MARK-MASQ rule to mark connections for SNAT
+// 	Marked connection will get SNAT on POSTROUTING Chain in nat table
+func (kl *Kubelet) syncNetworkUtil() {
+	if kl.iptablesMasqueradeBit < 0 || kl.iptablesMasqueradeBit > 31 {
+		glog.Errorf("invalid iptables-masquerade-bit %v not in [0, 31]", kl.iptablesMasqueradeBit)
+		return
+	}
+
+	if kl.iptablesDropBit < 0 || kl.iptablesDropBit > 31 {
+		glog.Errorf("invalid iptables-drop-bit %v not in [0, 31]", kl.iptablesDropBit)
+		return
+	}
+
+	if kl.iptablesDropBit == kl.iptablesMasqueradeBit {
+		glog.Errorf("iptables-masquerade-bit %v and iptables-drop-bit %v must be different", kl.iptablesMasqueradeBit, kl.iptablesDropBit)
+		return
+	}
+
+	// Setup KUBE-MARK-DROP rules
+	dropMark := getIPTablesMark(kl.iptablesDropBit)
+	if _, err := kl.iptClient.EnsureChain(utiliptables.TableNAT, KubeMarkDropChain); err != nil {
+		glog.Errorf("Failed to ensure that %s chain %s exists: %v", utiliptables.TableNAT, KubeMarkDropChain, err)
+		return
+	}
+	if _, err := kl.iptClient.EnsureRule(utiliptables.Append, utiliptables.TableNAT, KubeMarkDropChain, "-j", "MARK", "--set-xmark", dropMark); err != nil {
+		glog.Errorf("Failed to ensure marking rule for %v: %v", KubeMarkDropChain, err)
+		return
+	}
+	if _, err := kl.iptClient.EnsureChain(utiliptables.TableFilter, KubeFirewallChain); err != nil {
+		glog.Errorf("Failed to ensure that %s chain %s exists: %v", utiliptables.TableFilter, KubeFirewallChain, err)
+		return
+	}
+	if _, err := kl.iptClient.EnsureRule(utiliptables.Append, utiliptables.TableFilter, KubeFirewallChain,
+		"-m", "comment", "--comment", "kubernetes firewall for dropping marked packets",
+		"-m", "mark", "--mark", dropMark,
+		"-j", "DROP"); err != nil {
+		glog.Errorf("Failed to ensure rule to drop packet marked by %v in %v chain %v: %v", KubeMarkDropChain, utiliptables.TableFilter, KubeFirewallChain, err)
+		return
+	}
+	if _, err := kl.iptClient.EnsureRule(utiliptables.Prepend, utiliptables.TableFilter, utiliptables.ChainOutput, "-j", string(KubeFirewallChain)); err != nil {
+		glog.Errorf("Failed to ensure that %s chain %s jumps to %s: %v", utiliptables.TableFilter, utiliptables.ChainOutput, KubeFirewallChain, err)
+		return
+	}
+	if _, err := kl.iptClient.EnsureRule(utiliptables.Prepend, utiliptables.TableFilter, utiliptables.ChainInput, "-j", string(KubeFirewallChain)); err != nil {
+		glog.Errorf("Failed to ensure that %s chain %s jumps to %s: %v", utiliptables.TableFilter, utiliptables.ChainInput, KubeFirewallChain, err)
+		return
+	}
+
+	// Setup KUBE-MARK-MASQ rules
+	masqueradeMark := getIPTablesMark(kl.iptablesMasqueradeBit)
+	if _, err := kl.iptClient.EnsureChain(utiliptables.TableNAT, KubeMarkMasqChain); err != nil {
+		glog.Errorf("Failed to ensure that %s chain %s exists: %v", utiliptables.TableNAT, KubeMarkMasqChain, err)
+		return
+	}
+	if _, err := kl.iptClient.EnsureChain(utiliptables.TableNAT, KubePostroutingChain); err != nil {
+		glog.Errorf("Failed to ensure that %s chain %s exists: %v", utiliptables.TableNAT, KubePostroutingChain, err)
+		return
+	}
+	if _, err := kl.iptClient.EnsureRule(utiliptables.Append, utiliptables.TableNAT, KubeMarkMasqChain, "-j", "MARK", "--set-xmark", masqueradeMark); err != nil {
+		glog.Errorf("Failed to ensure marking rule for %v: %v", KubeMarkMasqChain, err)
+		return
+	}
+	if _, err := kl.iptClient.EnsureRule(utiliptables.Prepend, utiliptables.TableNAT, utiliptables.ChainPostrouting,
+		"-m", "comment", "--comment", "kubernetes postrouting rules", "-j", string(KubePostroutingChain)); err != nil {
+		glog.Errorf("Failed to ensure that %s chain %s jumps to %s: %v", utiliptables.TableNAT, utiliptables.ChainPostrouting, KubePostroutingChain, err)
+		return
+	}
+	if _, err := kl.iptClient.EnsureRule(utiliptables.Append, utiliptables.TableNAT, KubePostroutingChain,
+		"-m", "comment", "--comment", "kubernetes service traffic requiring SNAT",
+		"-m", "mark", "--mark", masqueradeMark, "-j", "MASQUERADE"); err != nil {
+		glog.Errorf("Failed to ensure SNAT rule for packets marked by %v in %v chain %v: %v", KubeMarkMasqChain, utiliptables.TableNAT, KubePostroutingChain, err)
+		return
+	}
+}
+
+// getIPTablesMark returns the fwmark given the bit
+func getIPTablesMark(bit int) string {
+	value := 1 << uint(bit)
+	return fmt.Sprintf("%#08x/%#08x", value, value)
+}

pkg/kubelet/kubelet_network_test.go

@@ -217,3 +217,25 @@ func TestCleanupBandwidthLimits(t *testing.T) {
 		}
 	}
 }
+
+func TestGetIPTablesMark(t *testing.T) {
+	tests := []struct {
+		bit    int
+		expect string
+	}{
+		{
+			14,
+			"0x00004000/0x00004000",
+		},
+		{
+			15,
+			"0x00008000/0x00008000",
+		},
+	}
+	for _, tc := range tests {
+		res := getIPTablesMark(tc.bit)
+		if res != tc.expect {
+			t.Errorf("getIPTablesMark output unexpected result: %v when input bit is %d. Expect result: %v", res, tc.bit, tc.expect)
+		}
+	}
+}

pkg/proxy/iptables/proxier.go

@@ -45,31 +45,35 @@ import (
 	utilsysctl "k8s.io/kubernetes/pkg/util/sysctl"
 )
 
-// iptablesMinVersion is the minimum version of iptables for which we will use the Proxier
-// from this package instead of the userspace Proxier.  While most of the
-// features we need were available earlier, the '-C' flag was added more
-// recently.  We use that indirectly in Ensure* functions, and if we don't
-// have it, we have to be extra careful about the exact args we feed in being
-// the same as the args we read back (iptables itself normalizes some args).
-// This is the "new" Proxier, so we require "new" versions of tools.
-const iptablesMinVersion = utiliptables.MinCheckVersion
+const (
+	// iptablesMinVersion is the minimum version of iptables for which we will use the Proxier
+	// from this package instead of the userspace Proxier.  While most of the
+	// features we need were available earlier, the '-C' flag was added more
+	// recently.  We use that indirectly in Ensure* functions, and if we don't
+	// have it, we have to be extra careful about the exact args we feed in being
+	// the same as the args we read back (iptables itself normalizes some args).
+	// This is the "new" Proxier, so we require "new" versions of tools.
+	iptablesMinVersion = utiliptables.MinCheckVersion
 
-// the services chain
-const kubeServicesChain utiliptables.Chain = "KUBE-SERVICES"
+	// the services chain
+	kubeServicesChain utiliptables.Chain = "KUBE-SERVICES"
 
-// the nodeports chain
-const kubeNodePortsChain utiliptables.Chain = "KUBE-NODEPORTS"
+	// the nodeports chain
+	kubeNodePortsChain utiliptables.Chain = "KUBE-NODEPORTS"
 
-// the kubernetes postrouting chain
-const kubePostroutingChain utiliptables.Chain = "KUBE-POSTROUTING"
+	// the kubernetes postrouting chain
+	kubePostroutingChain utiliptables.Chain = "KUBE-POSTROUTING"
 
-// the mark-for-masquerade chain
-// TODO: let kubelet manage this chain. Other component should just assume it exists and use it.
-const KubeMarkMasqChain utiliptables.Chain = "KUBE-MARK-MASQ"
+	// the mark-for-masquerade chain
+	KubeMarkMasqChain utiliptables.Chain = "KUBE-MARK-MASQ"
 
-// the mark we apply to traffic needing SNAT
-// TODO(thockin): Remove this for v1.3 or v1.4.
-const oldIptablesMasqueradeMark = "0x4d415351"
+	// the mark we apply to traffic needing SNAT
+	// TODO(thockin): Remove this for v1.3 or v1.4.
+	oldIptablesMasqueradeMark = "0x4d415351"
+
+	// the mark-for-drop chain
+	KubeMarkDropChain utiliptables.Chain = "KUBE-MARK-DROP"
+)
 
 // IptablesVersioner can query the current iptables version.
 type IptablesVersioner interface {
@@ -136,6 +140,7 @@ type serviceInfo struct {
 	sessionAffinityType      api.ServiceAffinity
 	stickyMaxAgeSeconds      int
 	externalIPs              []string
+	loadBalancerSourceRanges []string
 }
 
 // returns a new serviceInfo struct
@@ -164,6 +169,7 @@ type Proxier struct {
 	exec           utilexec.Interface
 	clusterCIDR    string
 	hostname       string
+	nodeIP         net.IP
 }
 
 type localPort struct {
@@ -189,7 +195,7 @@ var _ proxy.ProxyProvider = &Proxier{}
 // An error will be returned if iptables fails to update or acquire the initial lock.
 // Once a proxier is created, it will keep iptables up to date in the background and
 // will not terminate if a particular iptables call fails.
-func NewProxier(ipt utiliptables.Interface, exec utilexec.Interface, syncPeriod time.Duration, masqueradeAll bool, masqueradeBit int, clusterCIDR string, hostname string) (*Proxier, error) {
+func NewProxier(ipt utiliptables.Interface, exec utilexec.Interface, syncPeriod time.Duration, masqueradeAll bool, masqueradeBit int, clusterCIDR string, hostname string, nodeIP net.IP) (*Proxier, error) {
 	// Set the route_localnet sysctl we need for
 	if err := utilsysctl.SetSysctl(sysctlRouteLocalnet, 1); err != nil {
 		return nil, fmt.Errorf("can't set sysctl %s: %v", sysctlRouteLocalnet, err)
@@ -209,6 +215,10 @@ func NewProxier(ipt utiliptables.Interface, exec utilexec.Interface, syncPeriod
 	masqueradeValue := 1 << uint(masqueradeBit)
 	masqueradeMark := fmt.Sprintf("%#08x/%#08x", masqueradeValue, masqueradeValue)
 
+	if nodeIP == nil {
+		glog.Warningf("invalid nodeIP, initialize kube-proxy with 127.0.0.1 as nodeIP")
+		nodeIP = net.ParseIP("127.0.0.1")
+	}
 	return &Proxier{
 		serviceMap:     make(map[proxy.ServicePortName]*serviceInfo),
 		endpointsMap:   make(map[proxy.ServicePortName][]string),
@@ -220,6 +230,7 @@ func NewProxier(ipt utiliptables.Interface, exec utilexec.Interface, syncPeriod
 		exec:           exec,
 		clusterCIDR:    clusterCIDR,
 		hostname:       hostname,
+		nodeIP:         nodeIP,
 	}, nil
 }
 
@@ -428,6 +439,7 @@ func (proxier *Proxier) OnServiceUpdate(allServices []api.Service) {
 			// Deep-copy in case the service instance changes
 			info.loadBalancerStatus = *api.LoadBalancerStatusDeepCopy(&service.Status.LoadBalancer)
 			info.sessionAffinityType = service.Spec.SessionAffinity
+			info.loadBalancerSourceRanges = service.Spec.LoadBalancerSourceRanges
 			proxier.serviceMap[serviceName] = info
 
 			glog.V(4).Infof("added serviceInfo(%s): %s", serviceName, spew.Sdump(info))
@@ -552,15 +564,28 @@ func flattenValidEndpoints(endpoints []hostPortPair) []string {
 	return result
 }
 
-// servicePortChainName takes the ServicePortName for a service and
-// returns the associated iptables chain.  This is computed by hashing (sha256)
-// then encoding to base32 and truncating with the prefix "KUBE-SVC-".  We do
-// this because Iptables Chain Names must be <= 28 chars long, and the longer
-// they are the harder they are to read.
-func servicePortChainName(s proxy.ServicePortName, protocol string) utiliptables.Chain {
+// portProtoHash takes the ServicePortName and protocol for a service
+// returns the associated 16 character hash. This is computed by hashing (sha256)
+// then encoding to base32 and truncating to 16 chars. We do this because Iptables
+// Chain Names must be <= 28 chars long, and the longer they are the harder they are to read.
+func portProtoHash(s proxy.ServicePortName, protocol string) string {
 	hash := sha256.Sum256([]byte(s.String() + protocol))
 	encoded := base32.StdEncoding.EncodeToString(hash[:])
-	return utiliptables.Chain("KUBE-SVC-" + encoded[:16])
+	return encoded[:16]
+}
+
+// servicePortChainName takes the ServicePortName for a service and
+// returns the associated iptables chain.  This is computed by hashing (sha256)
+// then encoding to base32 and truncating with the prefix "KUBE-SVC-".
+func servicePortChainName(s proxy.ServicePortName, protocol string) utiliptables.Chain {
+	return utiliptables.Chain("KUBE-SVC-" + portProtoHash(s, protocol))
+}
+
+// servicePortChainName takes the ServicePortName for a service and
+// returns the associated iptables chain.  This is computed by hashing (sha256)
+// then encoding to base32 and truncating with the prefix "KUBE-FW-".
+func serviceFirewallChainName(s proxy.ServicePortName, protocol string) utiliptables.Chain {
+	return utiliptables.Chain("KUBE-FW-" + portProtoHash(s, protocol))
 }
 
 // This is the same as servicePortChainName but with the endpoint included.
@@ -854,9 +879,54 @@ func (proxier *Proxier) syncProxyRules() {
 					"-d", fmt.Sprintf("%s/32", ingress.IP),
 					"--dport", fmt.Sprintf("%d", svcInfo.port),
 				}
+				// create service firewall chain
+				fwChain := serviceFirewallChainName(svcName, protocol)
+				if chain, ok := existingNATChains[fwChain]; ok {
+					writeLine(natChains, chain)
+				} else {
+					writeLine(natChains, utiliptables.MakeChainLine(fwChain))
+				}
+				// jump to service firewall chain
+				// The service firewall rules are created based on ServiceSpec.loadBalancerSourceRanges field.
+				// This currently works for loadbalancers that preserves source ips.
+				// For loadbalancers which direct traffic to service NodePort, the firewall rules will not apply.
+				writeLine(natRules, append(args, "-j", string(fwChain))...)
+
+				args = []string{
+					"-A", string(fwChain),
+					"-m", "comment", "--comment", fmt.Sprintf(`"%s loadbalancer IP"`, svcName.String()),
+					"-m", protocol, "-p", protocol,
+					"-d", fmt.Sprintf("%s/32", ingress.IP),
+					"--dport", fmt.Sprintf("%d", svcInfo.port),
+				}
 				// We have to SNAT packets from external IPs.
 				writeLine(natRules, append(args, "-j", string(KubeMarkMasqChain))...)
+
+				if len(svcInfo.loadBalancerSourceRanges) == 0 {
+					// allow all sources, so jump directly to KUBE-SVC chain
 					writeLine(natRules, append(args, "-j", string(svcChain))...)
+				} else {
+					// firewall filter based on each source range
+					allowFromNode := false
+					for _, src := range svcInfo.loadBalancerSourceRanges {
+						writeLine(natRules, append(args, "-s", src, "-j", string(svcChain))...)
+						// ignore error because it has been validated
+						_, cidr, _ := net.ParseCIDR(src)
+						if cidr.Contains(proxier.nodeIP) {
+							allowFromNode = true
+						}
+					}
+					// generally, ip route rule was added to intercept request to loadbalancer vip from the
+					// loadbalancer's backend hosts. In this case, request will not hit the loadbalancer but loop back directly.
+					// Need to add the following rule to allow request on host.
+					if allowFromNode {
+						writeLine(natRules, append(args, "-s", fmt.Sprintf("%s/32", ingress.IP), "-j", string(svcChain))...)
+					}
+				}
+
+				// If the packet was able to reach the end of firewall chain, then it did not get DNATed.
+				// It means the packet cannot go thru the firewall, then mark it for DROP
+				writeLine(natRules, append(args, "-j", string(KubeMarkDropChain))...)
 			}
 		}