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proxier.go
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proxier.go
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/*
Copyright 2015 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License 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 iptables
//
// NOTE: this needs to be tested in e2e since it uses iptables for everything.
//
import (
"bytes"
"crypto/sha256"
"encoding/base32"
"fmt"
"net"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"k8s.io/klog"
"k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/types"
utilversion "k8s.io/apimachinery/pkg/util/version"
"k8s.io/apimachinery/pkg/util/wait"
"k8s.io/client-go/tools/record"
"k8s.io/kubernetes/pkg/proxy"
"k8s.io/kubernetes/pkg/proxy/healthcheck"
"k8s.io/kubernetes/pkg/proxy/metrics"
utilproxy "k8s.io/kubernetes/pkg/proxy/util"
"k8s.io/kubernetes/pkg/util/async"
"k8s.io/kubernetes/pkg/util/conntrack"
utiliptables "k8s.io/kubernetes/pkg/util/iptables"
utilsysctl "k8s.io/kubernetes/pkg/util/sysctl"
utilexec "k8s.io/utils/exec"
utilnet "k8s.io/utils/net"
)
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
kubeServicesChain utiliptables.Chain = "KUBE-SERVICES"
// the external services chain
kubeExternalServicesChain utiliptables.Chain = "KUBE-EXTERNAL-SERVICES"
// the nodeports chain
kubeNodePortsChain utiliptables.Chain = "KUBE-NODEPORTS"
// the kubernetes postrouting chain
kubePostroutingChain utiliptables.Chain = "KUBE-POSTROUTING"
// the mark-for-masquerade chain
KubeMarkMasqChain utiliptables.Chain = "KUBE-MARK-MASQ"
// the mark-for-drop chain
KubeMarkDropChain utiliptables.Chain = "KUBE-MARK-DROP"
// the kubernetes forward chain
kubeForwardChain utiliptables.Chain = "KUBE-FORWARD"
)
// IPTablesVersioner can query the current iptables version.
type IPTablesVersioner interface {
// returns "X.Y.Z"
GetVersion() (string, error)
}
// KernelCompatTester tests whether the required kernel capabilities are
// present to run the iptables proxier.
type KernelCompatTester interface {
IsCompatible() error
}
// CanUseIPTablesProxier returns true if we should use the iptables Proxier
// instead of the "classic" userspace Proxier. This is determined by checking
// the iptables version and for the existence of kernel features. It may return
// an error if it fails to get the iptables version without error, in which
// case it will also return false.
func CanUseIPTablesProxier(iptver IPTablesVersioner, kcompat KernelCompatTester) (bool, error) {
minVersion, err := utilversion.ParseGeneric(iptablesMinVersion)
if err != nil {
return false, err
}
versionString, err := iptver.GetVersion()
if err != nil {
return false, err
}
version, err := utilversion.ParseGeneric(versionString)
if err != nil {
return false, err
}
if version.LessThan(minVersion) {
return false, nil
}
// Check that the kernel supports what we need.
if err := kcompat.IsCompatible(); err != nil {
return false, err
}
return true, nil
}
type LinuxKernelCompatTester struct{}
func (lkct LinuxKernelCompatTester) IsCompatible() error {
// Check for the required sysctls. We don't care about the value, just
// that it exists. If this Proxier is chosen, we'll initialize it as we
// need.
_, err := utilsysctl.New().GetSysctl(sysctlRouteLocalnet)
return err
}
const sysctlRouteLocalnet = "net/ipv4/conf/all/route_localnet"
const sysctlBridgeCallIPTables = "net/bridge/bridge-nf-call-iptables"
// internal struct for string service information
type serviceInfo struct {
*proxy.BaseServiceInfo
// The following fields are computed and stored for performance reasons.
serviceNameString string
servicePortChainName utiliptables.Chain
serviceFirewallChainName utiliptables.Chain
serviceLBChainName utiliptables.Chain
}
// returns a new proxy.ServicePort which abstracts a serviceInfo
func newServiceInfo(port *v1.ServicePort, service *v1.Service, baseInfo *proxy.BaseServiceInfo) proxy.ServicePort {
info := &serviceInfo{BaseServiceInfo: baseInfo}
// Store the following for performance reasons.
svcName := types.NamespacedName{Namespace: service.Namespace, Name: service.Name}
svcPortName := proxy.ServicePortName{NamespacedName: svcName, Port: port.Name}
protocol := strings.ToLower(string(info.Protocol))
info.serviceNameString = svcPortName.String()
info.servicePortChainName = servicePortChainName(info.serviceNameString, protocol)
info.serviceFirewallChainName = serviceFirewallChainName(info.serviceNameString, protocol)
info.serviceLBChainName = serviceLBChainName(info.serviceNameString, protocol)
return info
}
// internal struct for endpoints information
type endpointsInfo struct {
*proxy.BaseEndpointInfo
// The following fields we lazily compute and store here for performance
// reasons. If the protocol is the same as you expect it to be, then the
// chainName can be reused, otherwise it should be recomputed.
protocol string
chainName utiliptables.Chain
}
// returns a new proxy.Endpoint which abstracts a endpointsInfo
func newEndpointInfo(baseInfo *proxy.BaseEndpointInfo) proxy.Endpoint {
return &endpointsInfo{BaseEndpointInfo: baseInfo}
}
// Equal overrides the Equal() function imlemented by proxy.BaseEndpointInfo.
func (e *endpointsInfo) Equal(other proxy.Endpoint) bool {
o, ok := other.(*endpointsInfo)
if !ok {
klog.Error("Failed to cast endpointsInfo")
return false
}
return e.Endpoint == o.Endpoint &&
e.IsLocal == o.IsLocal &&
e.protocol == o.protocol &&
e.chainName == o.chainName
}
// Returns the endpoint chain name for a given endpointsInfo.
func (e *endpointsInfo) endpointChain(svcNameString, protocol string) utiliptables.Chain {
if e.protocol != protocol {
e.protocol = protocol
e.chainName = servicePortEndpointChainName(svcNameString, protocol, e.Endpoint)
}
return e.chainName
}
// Proxier is an iptables based proxy for connections between a localhost:lport
// and services that provide the actual backends.
type Proxier struct {
// endpointsChanges and serviceChanges contains all changes to endpoints and
// services that happened since iptables was synced. For a single object,
// changes are accumulated, i.e. previous is state from before all of them,
// current is state after applying all of those.
endpointsChanges *proxy.EndpointChangeTracker
serviceChanges *proxy.ServiceChangeTracker
mu sync.Mutex // protects the following fields
serviceMap proxy.ServiceMap
endpointsMap proxy.EndpointsMap
portsMap map[utilproxy.LocalPort]utilproxy.Closeable
// endpointsSynced and servicesSynced are set to true when corresponding
// objects are synced after startup. This is used to avoid updating iptables
// with some partial data after kube-proxy restart.
endpointsSynced bool
servicesSynced bool
initialized int32
syncRunner *async.BoundedFrequencyRunner // governs calls to syncProxyRules
// These are effectively const and do not need the mutex to be held.
iptables utiliptables.Interface
masqueradeAll bool
masqueradeMark string
exec utilexec.Interface
clusterCIDR string
hostname string
nodeIP net.IP
portMapper utilproxy.PortOpener
recorder record.EventRecorder
healthChecker healthcheck.Server
healthzServer healthcheck.HealthzUpdater
// Since converting probabilities (floats) to strings is expensive
// and we are using only probabilities in the format of 1/n, we are
// precomputing some number of those and cache for future reuse.
precomputedProbabilities []string
// The following buffers are used to reuse memory and avoid allocations
// that are significantly impacting performance.
iptablesData *bytes.Buffer
existingFilterChainsData *bytes.Buffer
filterChains *bytes.Buffer
filterRules *bytes.Buffer
natChains *bytes.Buffer
natRules *bytes.Buffer
// endpointChainsNumber is the total amount of endpointChains across all
// services that we will generate (it is computed at the beginning of
// syncProxyRules method). If that is large enough, comments in some
// iptable rules are dropped to improve performance.
endpointChainsNumber int
// Values are as a parameter to select the interfaces where nodeport works.
nodePortAddresses []string
// networkInterfacer defines an interface for several net library functions.
// Inject for test purpose.
networkInterfacer utilproxy.NetworkInterfacer
}
// listenPortOpener opens ports by calling bind() and listen().
type listenPortOpener struct{}
// OpenLocalPort holds the given local port open.
func (l *listenPortOpener) OpenLocalPort(lp *utilproxy.LocalPort) (utilproxy.Closeable, error) {
return openLocalPort(lp)
}
// Proxier implements ProxyProvider
var _ proxy.ProxyProvider = &Proxier{}
// NewProxier returns a new Proxier given an iptables Interface instance.
// Because of the iptables logic, it is assumed that there is only a single Proxier active on a machine.
// 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,
sysctl utilsysctl.Interface,
exec utilexec.Interface,
syncPeriod time.Duration,
minSyncPeriod time.Duration,
masqueradeAll bool,
masqueradeBit int,
clusterCIDR string,
hostname string,
nodeIP net.IP,
recorder record.EventRecorder,
healthzServer healthcheck.HealthzUpdater,
nodePortAddresses []string,
) (*Proxier, error) {
// Set the route_localnet sysctl we need for
if val, _ := sysctl.GetSysctl(sysctlRouteLocalnet); val != 1 {
if err := sysctl.SetSysctl(sysctlRouteLocalnet, 1); err != nil {
return nil, fmt.Errorf("can't set sysctl %s: %v", sysctlRouteLocalnet, err)
}
}
// Proxy needs br_netfilter and bridge-nf-call-iptables=1 when containers
// are connected to a Linux bridge (but not SDN bridges). Until most
// plugins handle this, log when config is missing
if val, err := sysctl.GetSysctl(sysctlBridgeCallIPTables); err == nil && val != 1 {
klog.Warning("missing br-netfilter module or unset sysctl br-nf-call-iptables; proxy may not work as intended")
}
// Generate the masquerade mark to use for SNAT rules.
masqueradeValue := 1 << uint(masqueradeBit)
masqueradeMark := fmt.Sprintf("%#08x/%#08x", masqueradeValue, masqueradeValue)
if nodeIP == nil {
klog.Warning("invalid nodeIP, initializing kube-proxy with 127.0.0.1 as nodeIP")
nodeIP = net.ParseIP("127.0.0.1")
}
if len(clusterCIDR) == 0 {
klog.Warning("clusterCIDR not specified, unable to distinguish between internal and external traffic")
} else if utilnet.IsIPv6CIDRString(clusterCIDR) != ipt.IsIpv6() {
return nil, fmt.Errorf("clusterCIDR %s has incorrect IP version: expect isIPv6=%t", clusterCIDR, ipt.IsIpv6())
}
healthChecker := healthcheck.NewServer(hostname, recorder, nil, nil) // use default implementations of deps
isIPv6 := ipt.IsIpv6()
proxier := &Proxier{
portsMap: make(map[utilproxy.LocalPort]utilproxy.Closeable),
serviceMap: make(proxy.ServiceMap),
serviceChanges: proxy.NewServiceChangeTracker(newServiceInfo, &isIPv6, recorder),
endpointsMap: make(proxy.EndpointsMap),
endpointsChanges: proxy.NewEndpointChangeTracker(hostname, newEndpointInfo, &isIPv6, recorder),
iptables: ipt,
masqueradeAll: masqueradeAll,
masqueradeMark: masqueradeMark,
exec: exec,
clusterCIDR: clusterCIDR,
hostname: hostname,
nodeIP: nodeIP,
portMapper: &listenPortOpener{},
recorder: recorder,
healthChecker: healthChecker,
healthzServer: healthzServer,
precomputedProbabilities: make([]string, 0, 1001),
iptablesData: bytes.NewBuffer(nil),
existingFilterChainsData: bytes.NewBuffer(nil),
filterChains: bytes.NewBuffer(nil),
filterRules: bytes.NewBuffer(nil),
natChains: bytes.NewBuffer(nil),
natRules: bytes.NewBuffer(nil),
nodePortAddresses: nodePortAddresses,
networkInterfacer: utilproxy.RealNetwork{},
}
burstSyncs := 2
klog.V(3).Infof("minSyncPeriod: %v, syncPeriod: %v, burstSyncs: %d", minSyncPeriod, syncPeriod, burstSyncs)
proxier.syncRunner = async.NewBoundedFrequencyRunner("sync-runner", proxier.syncProxyRules, minSyncPeriod, syncPeriod, burstSyncs)
return proxier, nil
}
type iptablesJumpChain struct {
table utiliptables.Table
dstChain utiliptables.Chain
srcChain utiliptables.Chain
comment string
extraArgs []string
}
var iptablesJumpChains = []iptablesJumpChain{
{utiliptables.TableFilter, kubeExternalServicesChain, utiliptables.ChainInput, "kubernetes externally-visible service portals", []string{"-m", "conntrack", "--ctstate", "NEW"}},
{utiliptables.TableFilter, kubeServicesChain, utiliptables.ChainForward, "kubernetes service portals", []string{"-m", "conntrack", "--ctstate", "NEW"}},
{utiliptables.TableFilter, kubeServicesChain, utiliptables.ChainOutput, "kubernetes service portals", []string{"-m", "conntrack", "--ctstate", "NEW"}},
{utiliptables.TableFilter, kubeForwardChain, utiliptables.ChainForward, "kubernetes forwarding rules", nil},
{utiliptables.TableNAT, kubeServicesChain, utiliptables.ChainOutput, "kubernetes service portals", nil},
{utiliptables.TableNAT, kubeServicesChain, utiliptables.ChainPrerouting, "kubernetes service portals", nil},
{utiliptables.TableNAT, kubePostroutingChain, utiliptables.ChainPostrouting, "kubernetes postrouting rules", nil},
}
var iptablesCleanupOnlyChains = []iptablesJumpChain{}
// CleanupLeftovers removes all iptables rules and chains created by the Proxier
// It returns true if an error was encountered. Errors are logged.
func CleanupLeftovers(ipt utiliptables.Interface) (encounteredError bool) {
// Unlink our chains
for _, jump := range append(iptablesJumpChains, iptablesCleanupOnlyChains...) {
args := append(jump.extraArgs,
"-m", "comment", "--comment", jump.comment,
"-j", string(jump.dstChain),
)
if err := ipt.DeleteRule(jump.table, jump.srcChain, args...); err != nil {
if !utiliptables.IsNotFoundError(err) {
klog.Errorf("Error removing pure-iptables proxy rule: %v", err)
encounteredError = true
}
}
}
// Flush and remove all of our "-t nat" chains.
iptablesData := bytes.NewBuffer(nil)
if err := ipt.SaveInto(utiliptables.TableNAT, iptablesData); err != nil {
klog.Errorf("Failed to execute iptables-save for %s: %v", utiliptables.TableNAT, err)
encounteredError = true
} else {
existingNATChains := utiliptables.GetChainLines(utiliptables.TableNAT, iptablesData.Bytes())
natChains := bytes.NewBuffer(nil)
natRules := bytes.NewBuffer(nil)
writeLine(natChains, "*nat")
// Start with chains we know we need to remove.
for _, chain := range []utiliptables.Chain{kubeServicesChain, kubeNodePortsChain, kubePostroutingChain, KubeMarkMasqChain} {
if _, found := existingNATChains[chain]; found {
chainString := string(chain)
writeBytesLine(natChains, existingNATChains[chain]) // flush
writeLine(natRules, "-X", chainString) // delete
}
}
// Hunt for service and endpoint chains.
for chain := range existingNATChains {
chainString := string(chain)
if strings.HasPrefix(chainString, "KUBE-SVC-") || strings.HasPrefix(chainString, "KUBE-SEP-") || strings.HasPrefix(chainString, "KUBE-FW-") || strings.HasPrefix(chainString, "KUBE-XLB-") {
writeBytesLine(natChains, existingNATChains[chain]) // flush
writeLine(natRules, "-X", chainString) // delete
}
}
writeLine(natRules, "COMMIT")
natLines := append(natChains.Bytes(), natRules.Bytes()...)
// Write it.
err = ipt.Restore(utiliptables.TableNAT, natLines, utiliptables.NoFlushTables, utiliptables.RestoreCounters)
if err != nil {
klog.Errorf("Failed to execute iptables-restore for %s: %v", utiliptables.TableNAT, err)
encounteredError = true
}
}
// Flush and remove all of our "-t filter" chains.
iptablesData.Reset()
if err := ipt.SaveInto(utiliptables.TableFilter, iptablesData); err != nil {
klog.Errorf("Failed to execute iptables-save for %s: %v", utiliptables.TableFilter, err)
encounteredError = true
} else {
existingFilterChains := utiliptables.GetChainLines(utiliptables.TableFilter, iptablesData.Bytes())
filterChains := bytes.NewBuffer(nil)
filterRules := bytes.NewBuffer(nil)
writeLine(filterChains, "*filter")
for _, chain := range []utiliptables.Chain{kubeServicesChain, kubeExternalServicesChain, kubeForwardChain} {
if _, found := existingFilterChains[chain]; found {
chainString := string(chain)
writeBytesLine(filterChains, existingFilterChains[chain])
writeLine(filterRules, "-X", chainString)
}
}
writeLine(filterRules, "COMMIT")
filterLines := append(filterChains.Bytes(), filterRules.Bytes()...)
// Write it.
if err := ipt.Restore(utiliptables.TableFilter, filterLines, utiliptables.NoFlushTables, utiliptables.RestoreCounters); err != nil {
klog.Errorf("Failed to execute iptables-restore for %s: %v", utiliptables.TableFilter, err)
encounteredError = true
}
}
return encounteredError
}
func computeProbability(n int) string {
return fmt.Sprintf("%0.5f", 1.0/float64(n))
}
// This assumes proxier.mu is held
func (proxier *Proxier) precomputeProbabilities(numberOfPrecomputed int) {
if len(proxier.precomputedProbabilities) == 0 {
proxier.precomputedProbabilities = append(proxier.precomputedProbabilities, "<bad value>")
}
for i := len(proxier.precomputedProbabilities); i <= numberOfPrecomputed; i++ {
proxier.precomputedProbabilities = append(proxier.precomputedProbabilities, computeProbability(i))
}
}
// This assumes proxier.mu is held
func (proxier *Proxier) probability(n int) string {
if n >= len(proxier.precomputedProbabilities) {
proxier.precomputeProbabilities(n)
}
return proxier.precomputedProbabilities[n]
}
// Sync is called to synchronize the proxier state to iptables as soon as possible.
func (proxier *Proxier) Sync() {
proxier.syncRunner.Run()
}
// SyncLoop runs periodic work. This is expected to run as a goroutine or as the main loop of the app. It does not return.
func (proxier *Proxier) SyncLoop() {
// Update healthz timestamp at beginning in case Sync() never succeeds.
if proxier.healthzServer != nil {
proxier.healthzServer.UpdateTimestamp()
}
proxier.syncRunner.Loop(wait.NeverStop)
}
func (proxier *Proxier) setInitialized(value bool) {
var initialized int32
if value {
initialized = 1
}
atomic.StoreInt32(&proxier.initialized, initialized)
}
func (proxier *Proxier) isInitialized() bool {
return atomic.LoadInt32(&proxier.initialized) > 0
}
func (proxier *Proxier) OnServiceAdd(service *v1.Service) {
proxier.OnServiceUpdate(nil, service)
}
func (proxier *Proxier) OnServiceUpdate(oldService, service *v1.Service) {
if proxier.serviceChanges.Update(oldService, service) && proxier.isInitialized() {
proxier.syncRunner.Run()
}
}
func (proxier *Proxier) OnServiceDelete(service *v1.Service) {
proxier.OnServiceUpdate(service, nil)
}
func (proxier *Proxier) OnServiceSynced() {
proxier.mu.Lock()
proxier.servicesSynced = true
proxier.setInitialized(proxier.servicesSynced && proxier.endpointsSynced)
proxier.mu.Unlock()
// Sync unconditionally - this is called once per lifetime.
proxier.syncProxyRules()
}
func (proxier *Proxier) OnEndpointsAdd(endpoints *v1.Endpoints) {
proxier.OnEndpointsUpdate(nil, endpoints)
}
func (proxier *Proxier) OnEndpointsUpdate(oldEndpoints, endpoints *v1.Endpoints) {
if proxier.endpointsChanges.Update(oldEndpoints, endpoints) && proxier.isInitialized() {
proxier.syncRunner.Run()
}
}
func (proxier *Proxier) OnEndpointsDelete(endpoints *v1.Endpoints) {
proxier.OnEndpointsUpdate(endpoints, nil)
}
func (proxier *Proxier) OnEndpointsSynced() {
proxier.mu.Lock()
proxier.endpointsSynced = true
proxier.setInitialized(proxier.servicesSynced && proxier.endpointsSynced)
proxier.mu.Unlock()
// Sync unconditionally - this is called once per lifetime.
proxier.syncProxyRules()
}
// 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(servicePortName string, protocol string) string {
hash := sha256.Sum256([]byte(servicePortName + protocol))
encoded := base32.StdEncoding.EncodeToString(hash[:])
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(servicePortName string, protocol string) utiliptables.Chain {
return utiliptables.Chain("KUBE-SVC-" + portProtoHash(servicePortName, protocol))
}
// serviceFirewallChainName 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(servicePortName string, protocol string) utiliptables.Chain {
return utiliptables.Chain("KUBE-FW-" + portProtoHash(servicePortName, protocol))
}
// serviceLBPortChainName 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-XLB-". We do
// this because IPTables Chain Names must be <= 28 chars long, and the longer
// they are the harder they are to read.
func serviceLBChainName(servicePortName string, protocol string) utiliptables.Chain {
return utiliptables.Chain("KUBE-XLB-" + portProtoHash(servicePortName, protocol))
}
// This is the same as servicePortChainName but with the endpoint included.
func servicePortEndpointChainName(servicePortName string, protocol string, endpoint string) utiliptables.Chain {
hash := sha256.Sum256([]byte(servicePortName + protocol + endpoint))
encoded := base32.StdEncoding.EncodeToString(hash[:])
return utiliptables.Chain("KUBE-SEP-" + encoded[:16])
}
// After a UDP endpoint has been removed, we must flush any pending conntrack entries to it, or else we
// risk sending more traffic to it, all of which will be lost (because UDP).
// This assumes the proxier mutex is held
// TODO: move it to util
func (proxier *Proxier) deleteEndpointConnections(connectionMap []proxy.ServiceEndpoint) {
for _, epSvcPair := range connectionMap {
if svcInfo, ok := proxier.serviceMap[epSvcPair.ServicePortName]; ok && svcInfo.GetProtocol() == v1.ProtocolUDP {
endpointIP := utilproxy.IPPart(epSvcPair.Endpoint)
nodePort := svcInfo.GetNodePort()
var err error
if nodePort != 0 {
err = conntrack.ClearEntriesForPortNAT(proxier.exec, endpointIP, nodePort, v1.ProtocolUDP)
} else {
err = conntrack.ClearEntriesForNAT(proxier.exec, svcInfo.ClusterIPString(), endpointIP, v1.ProtocolUDP)
}
if err != nil {
klog.Errorf("Failed to delete %s endpoint connections, error: %v", epSvcPair.ServicePortName.String(), err)
}
for _, extIP := range svcInfo.ExternalIPStrings() {
err := conntrack.ClearEntriesForNAT(proxier.exec, extIP, endpointIP, v1.ProtocolUDP)
if err != nil {
klog.Errorf("Failed to delete %s endpoint connections for externalIP %s, error: %v", epSvcPair.ServicePortName.String(), extIP, err)
}
}
for _, lbIP := range svcInfo.LoadBalancerIPStrings() {
err := conntrack.ClearEntriesForNAT(proxier.exec, lbIP, endpointIP, v1.ProtocolUDP)
if err != nil {
klog.Errorf("Failed to delete %s endpoint connections for LoabBalancerIP %s, error: %v", epSvcPair.ServicePortName.String(), lbIP, err)
}
}
}
}
}
const endpointChainsNumberThreshold = 1000
// Assumes proxier.mu is held.
func (proxier *Proxier) appendServiceCommentLocked(args []string, svcName string) {
// Not printing these comments, can reduce size of iptables (in case of large
// number of endpoints) even by 40%+. So if total number of endpoint chains
// is large enough, we simply drop those comments.
if proxier.endpointChainsNumber > endpointChainsNumberThreshold {
return
}
args = append(args, "-m", "comment", "--comment", svcName)
}
// This is where all of the iptables-save/restore calls happen.
// The only other iptables rules are those that are setup in iptablesInit()
// This assumes proxier.mu is NOT held
func (proxier *Proxier) syncProxyRules() {
proxier.mu.Lock()
defer proxier.mu.Unlock()
start := time.Now()
defer func() {
metrics.SyncProxyRulesLatency.Observe(metrics.SinceInSeconds(start))
metrics.DeprecatedSyncProxyRulesLatency.Observe(metrics.SinceInMicroseconds(start))
klog.V(4).Infof("syncProxyRules took %v", time.Since(start))
}()
// don't sync rules till we've received services and endpoints
if !proxier.endpointsSynced || !proxier.servicesSynced {
klog.V(2).Info("Not syncing iptables until Services and Endpoints have been received from master")
return
}
// We assume that if this was called, we really want to sync them,
// even if nothing changed in the meantime. In other words, callers are
// responsible for detecting no-op changes and not calling this function.
serviceUpdateResult := proxy.UpdateServiceMap(proxier.serviceMap, proxier.serviceChanges)
endpointUpdateResult := proxy.UpdateEndpointsMap(proxier.endpointsMap, proxier.endpointsChanges)
staleServices := serviceUpdateResult.UDPStaleClusterIP
// merge stale services gathered from updateEndpointsMap
for _, svcPortName := range endpointUpdateResult.StaleServiceNames {
if svcInfo, ok := proxier.serviceMap[svcPortName]; ok && svcInfo != nil && svcInfo.GetProtocol() == v1.ProtocolUDP {
klog.V(2).Infof("Stale udp service %v -> %s", svcPortName, svcInfo.ClusterIPString())
staleServices.Insert(svcInfo.ClusterIPString())
}
}
klog.V(3).Info("Syncing iptables rules")
// Create and link the kube chains.
for _, jump := range iptablesJumpChains {
if _, err := proxier.iptables.EnsureChain(jump.table, jump.dstChain); err != nil {
klog.Errorf("Failed to ensure that %s chain %s exists: %v", jump.table, jump.dstChain, err)
return
}
args := append(jump.extraArgs,
"-m", "comment", "--comment", jump.comment,
"-j", string(jump.dstChain),
)
if _, err := proxier.iptables.EnsureRule(utiliptables.Prepend, jump.table, jump.srcChain, args...); err != nil {
klog.Errorf("Failed to ensure that %s chain %s jumps to %s: %v", jump.table, jump.srcChain, jump.dstChain, err)
return
}
}
//
// Below this point we will not return until we try to write the iptables rules.
//
// Get iptables-save output so we can check for existing chains and rules.
// This will be a map of chain name to chain with rules as stored in iptables-save/iptables-restore
existingFilterChains := make(map[utiliptables.Chain][]byte)
proxier.existingFilterChainsData.Reset()
err := proxier.iptables.SaveInto(utiliptables.TableFilter, proxier.existingFilterChainsData)
if err != nil { // if we failed to get any rules
klog.Errorf("Failed to execute iptables-save, syncing all rules: %v", err)
} else { // otherwise parse the output
existingFilterChains = utiliptables.GetChainLines(utiliptables.TableFilter, proxier.existingFilterChainsData.Bytes())
}
// IMPORTANT: existingNATChains may share memory with proxier.iptablesData.
existingNATChains := make(map[utiliptables.Chain][]byte)
proxier.iptablesData.Reset()
err = proxier.iptables.SaveInto(utiliptables.TableNAT, proxier.iptablesData)
if err != nil { // if we failed to get any rules
klog.Errorf("Failed to execute iptables-save, syncing all rules: %v", err)
} else { // otherwise parse the output
existingNATChains = utiliptables.GetChainLines(utiliptables.TableNAT, proxier.iptablesData.Bytes())
}
// Reset all buffers used later.
// This is to avoid memory reallocations and thus improve performance.
proxier.filterChains.Reset()
proxier.filterRules.Reset()
proxier.natChains.Reset()
proxier.natRules.Reset()
// Write table headers.
writeLine(proxier.filterChains, "*filter")
writeLine(proxier.natChains, "*nat")
// Make sure we keep stats for the top-level chains, if they existed
// (which most should have because we created them above).
for _, chainName := range []utiliptables.Chain{kubeServicesChain, kubeExternalServicesChain, kubeForwardChain} {
if chain, ok := existingFilterChains[chainName]; ok {
writeBytesLine(proxier.filterChains, chain)
} else {
writeLine(proxier.filterChains, utiliptables.MakeChainLine(chainName))
}
}
for _, chainName := range []utiliptables.Chain{kubeServicesChain, kubeNodePortsChain, kubePostroutingChain, KubeMarkMasqChain} {
if chain, ok := existingNATChains[chainName]; ok {
writeBytesLine(proxier.natChains, chain)
} else {
writeLine(proxier.natChains, utiliptables.MakeChainLine(chainName))
}
}
// Install the kubernetes-specific postrouting rules. We use a whole chain for
// this so that it is easier to flush and change, for example if the mark
// value should ever change.
writeLine(proxier.natRules, []string{
"-A", string(kubePostroutingChain),
"-m", "comment", "--comment", `"kubernetes service traffic requiring SNAT"`,
"-m", "mark", "--mark", proxier.masqueradeMark,
"-j", "MASQUERADE",
}...)
// Install the kubernetes-specific masquerade mark rule. We use a whole chain for
// this so that it is easier to flush and change, for example if the mark
// value should ever change.
writeLine(proxier.natRules, []string{
"-A", string(KubeMarkMasqChain),
"-j", "MARK", "--set-xmark", proxier.masqueradeMark,
}...)
// Accumulate NAT chains to keep.
activeNATChains := map[utiliptables.Chain]bool{} // use a map as a set
// Accumulate the set of local ports that we will be holding open once this update is complete
replacementPortsMap := map[utilproxy.LocalPort]utilproxy.Closeable{}
// We are creating those slices ones here to avoid memory reallocations
// in every loop. Note that reuse the memory, instead of doing:
// slice = <some new slice>
// you should always do one of the below:
// slice = slice[:0] // and then append to it
// slice = append(slice[:0], ...)
endpoints := make([]*endpointsInfo, 0)
endpointChains := make([]utiliptables.Chain, 0)
// To avoid growing this slice, we arbitrarily set its size to 64,
// there is never more than that many arguments for a single line.
// Note that even if we go over 64, it will still be correct - it
// is just for efficiency, not correctness.
args := make([]string, 64)
// Compute total number of endpoint chains across all services.
proxier.endpointChainsNumber = 0
for svcName := range proxier.serviceMap {
proxier.endpointChainsNumber += len(proxier.endpointsMap[svcName])
}
// Build rules for each service.
for svcName, svc := range proxier.serviceMap {
svcInfo, ok := svc.(*serviceInfo)
if !ok {
klog.Errorf("Failed to cast serviceInfo %q", svcName.String())
continue
}
isIPv6 := utilnet.IsIPv6(svcInfo.ClusterIP)
protocol := strings.ToLower(string(svcInfo.Protocol))
svcNameString := svcInfo.serviceNameString
hasEndpoints := len(proxier.endpointsMap[svcName]) > 0
svcChain := svcInfo.servicePortChainName
if hasEndpoints {
// Create the per-service chain, retaining counters if possible.
if chain, ok := existingNATChains[svcChain]; ok {
writeBytesLine(proxier.natChains, chain)
} else {
writeLine(proxier.natChains, utiliptables.MakeChainLine(svcChain))
}
activeNATChains[svcChain] = true
}
svcXlbChain := svcInfo.serviceLBChainName
if svcInfo.OnlyNodeLocalEndpoints {
// Only for services request OnlyLocal traffic
// create the per-service LB chain, retaining counters if possible.
if lbChain, ok := existingNATChains[svcXlbChain]; ok {
writeBytesLine(proxier.natChains, lbChain)
} else {
writeLine(proxier.natChains, utiliptables.MakeChainLine(svcXlbChain))
}
activeNATChains[svcXlbChain] = true
}
// Capture the clusterIP.
if hasEndpoints {
args = append(args[:0],
"-A", string(kubeServicesChain),
"-m", "comment", "--comment", fmt.Sprintf(`"%s cluster IP"`, svcNameString),
"-m", protocol, "-p", protocol,
"-d", utilproxy.ToCIDR(svcInfo.ClusterIP),
"--dport", strconv.Itoa(svcInfo.Port),
)
if proxier.masqueradeAll {
writeLine(proxier.natRules, append(args, "-j", string(KubeMarkMasqChain))...)
} else if len(proxier.clusterCIDR) > 0 {
// This masquerades off-cluster traffic to a service VIP. The idea
// is that you can establish a static route for your Service range,
// routing to any node, and that node will bridge into the Service
// for you. Since that might bounce off-node, we masquerade here.
// If/when we support "Local" policy for VIPs, we should update this.
writeLine(proxier.natRules, append(args, "! -s", proxier.clusterCIDR, "-j", string(KubeMarkMasqChain))...)
}
writeLine(proxier.natRules, append(args, "-j", string(svcChain))...)
} else {
writeLine(proxier.filterRules,
"-A", string(kubeServicesChain),
"-m", "comment", "--comment", fmt.Sprintf(`"%s has no endpoints"`, svcNameString),
"-m", protocol, "-p", protocol,
"-d", utilproxy.ToCIDR(svcInfo.ClusterIP),
"--dport", strconv.Itoa(svcInfo.Port),
"-j", "REJECT",
)
}
// Capture externalIPs.
for _, externalIP := range svcInfo.ExternalIPs {
// If the "external" IP happens to be an IP that is local to this
// machine, hold the local port open so no other process can open it
// (because the socket might open but it would never work).
if local, err := utilproxy.IsLocalIP(externalIP); err != nil {
klog.Errorf("can't determine if IP is local, assuming not: %v", err)
} else if local && (svcInfo.GetProtocol() != v1.ProtocolSCTP) {
lp := utilproxy.LocalPort{
Description: "externalIP for " + svcNameString,
IP: externalIP,
Port: svcInfo.Port,
Protocol: protocol,
}
if proxier.portsMap[lp] != nil {
klog.V(4).Infof("Port %s was open before and is still needed", lp.String())
replacementPortsMap[lp] = proxier.portsMap[lp]
} else {
socket, err := proxier.portMapper.OpenLocalPort(&lp)
if err != nil {
msg := fmt.Sprintf("can't open %s, skipping this externalIP: %v", lp.String(), err)
proxier.recorder.Eventf(
&v1.ObjectReference{
Kind: "Node",
Name: proxier.hostname,
UID: types.UID(proxier.hostname),
Namespace: "",
}, v1.EventTypeWarning, err.Error(), msg)
klog.Error(msg)
continue
}
replacementPortsMap[lp] = socket
}
}
if hasEndpoints {
args = append(args[:0],
"-A", string(kubeServicesChain),
"-m", "comment", "--comment", fmt.Sprintf(`"%s external IP"`, svcNameString),
"-m", protocol, "-p", protocol,
"-d", utilproxy.ToCIDR(net.ParseIP(externalIP)),
"--dport", strconv.Itoa(svcInfo.Port),
)
// We have to SNAT packets to external IPs.
writeLine(proxier.natRules, append(args, "-j", string(KubeMarkMasqChain))...)
// Allow traffic for external IPs that does not come from a bridge (i.e. not from a container)
// nor from a local process to be forwarded to the service.
// This rule roughly translates to "all traffic from off-machine".
// This is imperfect in the face of network plugins that might not use a bridge, but we can revisit that later.
externalTrafficOnlyArgs := append(args,
"-m", "physdev", "!", "--physdev-is-in",
"-m", "addrtype", "!", "--src-type", "LOCAL")
writeLine(proxier.natRules, append(externalTrafficOnlyArgs, "-j", string(svcChain))...)
dstLocalOnlyArgs := append(args, "-m", "addrtype", "--dst-type", "LOCAL")
// Allow traffic bound for external IPs that happen to be recognized as local IPs to stay local.
// This covers cases like GCE load-balancers which get added to the local routing table.
writeLine(proxier.natRules, append(dstLocalOnlyArgs, "-j", string(svcChain))...)
} else {
writeLine(proxier.filterRules,
"-A", string(kubeExternalServicesChain),
"-m", "comment", "--comment", fmt.Sprintf(`"%s has no endpoints"`, svcNameString),
"-m", protocol, "-p", protocol,
"-d", utilproxy.ToCIDR(net.ParseIP(externalIP)),
"--dport", strconv.Itoa(svcInfo.Port),
"-j", "REJECT",
)
}
}
// Capture load-balancer ingress.
if hasEndpoints {
fwChain := svcInfo.serviceFirewallChainName
for _, ingress := range svcInfo.LoadBalancerStatus.Ingress {
if ingress.IP != "" {
// create service firewall chain
if chain, ok := existingNATChains[fwChain]; ok {
writeBytesLine(proxier.natChains, chain)
} else {
writeLine(proxier.natChains, utiliptables.MakeChainLine(fwChain))
}
activeNATChains[fwChain] = true
// 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.
args = append(args[:0],
"-A", string(kubeServicesChain),
"-m", "comment", "--comment", fmt.Sprintf(`"%s loadbalancer IP"`, svcNameString),
"-m", protocol, "-p", protocol,
"-d", utilproxy.ToCIDR(net.ParseIP(ingress.IP)),
"--dport", strconv.Itoa(svcInfo.Port),
)
// jump to service firewall chain
writeLine(proxier.natRules, append(args, "-j", string(fwChain))...)
args = append(args[:0],
"-A", string(fwChain),
"-m", "comment", "--comment", fmt.Sprintf(`"%s loadbalancer IP"`, svcNameString),
)
// Each source match rule in the FW chain may jump to either the SVC or the XLB chain
chosenChain := svcXlbChain
// If we are proxying globally, we need to masquerade in case we cross nodes.
// If we are proxying only locally, we can retain the source IP.
if !svcInfo.OnlyNodeLocalEndpoints {
writeLine(proxier.natRules, append(args, "-j", string(KubeMarkMasqChain))...)
chosenChain = svcChain
}
if len(svcInfo.LoadBalancerSourceRanges) == 0 {
// allow all sources, so jump directly to the KUBE-SVC or KUBE-XLB chain
writeLine(proxier.natRules, append(args, "-j", string(chosenChain))...)
} else {
// firewall filter based on each source range
allowFromNode := false
for _, src := range svcInfo.LoadBalancerSourceRanges {
writeLine(proxier.natRules, append(args, "-s", src, "-j", string(chosenChain))...)
// 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(proxier.natRules, append(args, "-s", utilproxy.ToCIDR(net.ParseIP(ingress.IP)), "-j", string(chosenChain))...)
}
}
// 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(proxier.natRules, append(args, "-j", string(KubeMarkDropChain))...)
}
}
}
// FIXME: do we need REJECT rules for load-balancer ingress if !hasEndpoints?