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@@ -302,15 +302,29 @@ type Proxier struct {
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loadBalancer LoadBalancer
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mu sync.Mutex // protects serviceMap
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serviceMap map[string]*serviceInfo
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listenAddress net.IP
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listenIP net.IP
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iptables iptables.Interface
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hostIP net.IP
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}
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// NewProxier returns a new Proxier given a LoadBalancer and an address on
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// which to listen. Because of the iptables logic, It is assumed that there
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// is only a single Proxier active on a machine.
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func NewProxier(loadBalancer LoadBalancer, listenAddress net.IP, iptables iptables.Interface) *Proxier {
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func NewProxier(loadBalancer LoadBalancer, listenIP net.IP, iptables iptables.Interface) *Proxier {
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if listenIP.Equal(localhostIPv4) || listenIP.Equal(localhostIPv6) {
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glog.Errorf("Can't proxy only on localhost - iptables can't do it")
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return nil
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}
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hostIP, err := chooseHostInterface()
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if err != nil {
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glog.Errorf("Failed to select a host interface: %v", err)
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return nil
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}
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glog.Infof("Initializing iptables")
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// Clean up old messes. Ignore erors.
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iptablesDeleteOld(iptables)
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// Set up the iptables foundations we need.
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if err := iptablesInit(iptables); err != nil {
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glog.Errorf("Failed to initialize iptables: %v", err)
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@@ -325,8 +339,9 @@ func NewProxier(loadBalancer LoadBalancer, listenAddress net.IP, iptables iptabl
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return &Proxier{
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loadBalancer: loadBalancer,
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serviceMap: make(map[string]*serviceInfo),
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listenAddress: listenAddress,
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listenIP: listenIP,
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iptables: iptables,
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hostIP: hostIP,
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}
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}
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@@ -400,7 +415,7 @@ func (proxier *Proxier) setServiceInfo(service string, info *serviceInfo) {
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// Pass proxyPort=0 to allocate a random port. The timeout only applies to UDP
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// connections, for now.
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func (proxier *Proxier) addServiceOnPort(service string, protocol api.Protocol, proxyPort int, timeout time.Duration) (*serviceInfo, error) {
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sock, err := newProxySocket(protocol, proxier.listenAddress, proxyPort)
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sock, err := newProxySocket(protocol, proxier.listenIP, proxyPort)
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if err != nil {
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return nil, err
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}
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@@ -514,83 +529,127 @@ func ipsEqual(lhs, rhs []string) bool {
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}
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func (proxier *Proxier) openPortal(service string, info *serviceInfo) error {
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args := iptablesPortalArgs(info.portalIP, info.portalPort, info.protocol, proxier.listenAddress, info.proxyPort, service)
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existed, err := proxier.iptables.EnsureRule(iptables.TableNAT, iptablesProxyChain, args...)
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err := proxier.openOnePortal(info.portalIP, info.portalPort, info.protocol, proxier.listenIP, info.proxyPort, service)
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if err != nil {
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glog.Errorf("Failed to install iptables %s rule for service %q", iptablesProxyChain, service)
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return err
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}
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if !existed {
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glog.Infof("Opened iptables portal for service %q on %s:%d", service, info.portalIP, info.portalPort)
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for _, publicIP := range info.publicIP {
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err = proxier.openOnePortal(net.ParseIP(publicIP), info.portalPort, info.protocol, proxier.listenIP, info.proxyPort, service)
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if err != nil {
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return err
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}
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if len(info.publicIP) > 0 {
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return proxier.openExternalPortal(service, info)
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}
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return nil
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}
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func (proxier *Proxier) openExternalPortal(service string, info *serviceInfo) error {
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for _, publicIP := range info.publicIP {
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args := iptablesPortalArgs(net.ParseIP(publicIP), info.portalPort, info.protocol, proxier.listenAddress, info.proxyPort, service)
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existed, err := proxier.iptables.EnsureRule(iptables.TableNAT, iptablesProxyChain, args...)
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func (proxier *Proxier) openOnePortal(portalIP net.IP, portalPort int, protocol api.Protocol, proxyIP net.IP, proxyPort int, name string) error {
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// Handle traffic from containers.
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args := proxier.iptablesContainerPortalArgs(portalIP, portalPort, protocol, proxyIP, proxyPort, name)
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existed, err := proxier.iptables.EnsureRule(iptables.TableNAT, iptablesContainerPortalChain, args...)
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if err != nil {
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glog.Errorf("Failed to install iptables %s rule for service %q", iptablesProxyChain, service)
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glog.Errorf("Failed to install iptables %s rule for service %q", iptablesContainerPortalChain, name)
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return err
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}
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if !existed {
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glog.Infof("Opened iptables external portal for service %q on %s:%d", service, publicIP, info.proxyPort)
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glog.Infof("Opened iptables from-containers portal for service %q on %s %s:%d", name, protocol, portalIP, portalPort)
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}
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// Handle traffic from the host.
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args = proxier.iptablesHostPortalArgs(portalIP, portalPort, protocol, proxyIP, proxyPort, name)
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existed, err = proxier.iptables.EnsureRule(iptables.TableNAT, iptablesHostPortalChain, args...)
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if err != nil {
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glog.Errorf("Failed to install iptables %s rule for service %q", iptablesHostPortalChain, name)
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return err
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}
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if !existed {
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glog.Infof("Opened iptables from-host portal for service %q on %s %s:%d", name, protocol, portalIP, portalPort)
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}
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return nil
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}
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func (proxier *Proxier) closePortal(service string, info *serviceInfo) error {
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args := iptablesPortalArgs(info.portalIP, info.portalPort, info.protocol, proxier.listenAddress, info.proxyPort, service)
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if err := proxier.iptables.DeleteRule(iptables.TableNAT, iptablesProxyChain, args...); err != nil {
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glog.Errorf("Failed to delete iptables %s rule for service %q", iptablesProxyChain, service)
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return err
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}
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if len(info.publicIP) > 0 {
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return proxier.closeExternalPortal(service, info)
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}
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glog.Infof("Closed iptables portal for service %q", service)
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return nil
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}
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func (proxier *Proxier) closeExternalPortal(service string, info *serviceInfo) error {
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// Collect errors and report them all at the end.
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el := proxier.closeOnePortal(info.portalIP, info.portalPort, info.protocol, proxier.listenIP, info.proxyPort, service)
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for _, publicIP := range info.publicIP {
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args := iptablesPortalArgs(net.ParseIP(publicIP), info.portalPort, info.protocol, proxier.listenAddress, info.proxyPort, service)
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if err := proxier.iptables.DeleteRule(iptables.TableNAT, iptablesProxyChain, args...); err != nil {
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glog.Errorf("Failed to delete external iptables %s rule for service %q", iptablesProxyChain, service)
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return err
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el = append(el, proxier.closeOnePortal(net.ParseIP(publicIP), info.portalPort, info.protocol, proxier.listenIP, info.proxyPort, service)...)
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}
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if len(el) == 0 {
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glog.Infof("Closed iptables portals for service %q", service)
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} else {
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glog.Errorf("Some errors closing iptables portals for service %q", service)
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}
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glog.Infof("Closed external iptables portal for service %q", service)
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return nil
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return util.SliceToError(el)
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}
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var iptablesProxyChain iptables.Chain = "KUBE-PROXY"
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func (proxier *Proxier) closeOnePortal(portalIP net.IP, portalPort int, protocol api.Protocol, proxyIP net.IP, proxyPort int, name string) []error {
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el := []error{}
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// Handle traffic from containers.
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args := proxier.iptablesContainerPortalArgs(portalIP, portalPort, protocol, proxyIP, proxyPort, name)
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if err := proxier.iptables.DeleteRule(iptables.TableNAT, iptablesContainerPortalChain, args...); err != nil {
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glog.Errorf("Failed to delete iptables %s rule for service %q", iptablesContainerPortalChain, name)
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el = append(el, err)
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}
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// Handle traffic from the host.
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args = proxier.iptablesHostPortalArgs(portalIP, portalPort, protocol, proxyIP, proxyPort, name)
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if err := proxier.iptables.DeleteRule(iptables.TableNAT, iptablesHostPortalChain, args...); err != nil {
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glog.Errorf("Failed to delete iptables %s rule for service %q", iptablesHostPortalChain, name)
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el = append(el, err)
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}
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return el
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}
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// See comments in the *PortalArgs() functions for some details about why we
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// use two chains.
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var iptablesContainerPortalChain iptables.Chain = "KUBE-PORTALS-CONTAINER"
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var iptablesHostPortalChain iptables.Chain = "KUBE-PORTALS-HOST"
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var iptablesOldPortalChain iptables.Chain = "KUBE-PROXY"
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// Ensure that the iptables infrastructure we use is set up. This can safely be called periodically.
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func iptablesInit(ipt iptables.Interface) error {
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// TODO: There is almost certainly room for optimization here. E.g. If
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// we knew the portal_net CIDR we could fast-track outbound packets not
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// destined for a service. There's probably more, help wanted.
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if _, err := ipt.EnsureChain(iptables.TableNAT, iptablesProxyChain); err != nil {
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if _, err := ipt.EnsureChain(iptables.TableNAT, iptablesContainerPortalChain); err != nil {
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return err
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}
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if _, err := ipt.EnsureRule(iptables.TableNAT, iptables.ChainPrerouting, "-j", string(iptablesProxyChain)); err != nil {
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if _, err := ipt.EnsureRule(iptables.TableNAT, iptables.ChainPrerouting, "-j", string(iptablesContainerPortalChain)); err != nil {
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return err
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}
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if _, err := ipt.EnsureRule(iptables.TableNAT, iptables.ChainOutput, "-j", string(iptablesProxyChain)); err != nil {
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if _, err := ipt.EnsureChain(iptables.TableNAT, iptablesHostPortalChain); err != nil {
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return err
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}
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if _, err := ipt.EnsureRule(iptables.TableNAT, iptables.ChainOutput, "-j", string(iptablesHostPortalChain)); err != nil {
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return err
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}
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return nil
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}
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func iptablesDeleteOld(ipt iptables.Interface) {
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// DEPRECATED: The iptablesOldPortalChain is from when we had a single chain
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// for all rules. We'll unilaterally delete it here. We will remove this
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// code at some future date (before 1.0).
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ipt.DeleteRule(iptables.TableNAT, iptables.ChainPrerouting, "-j", string(iptablesOldPortalChain))
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ipt.DeleteRule(iptables.TableNAT, iptables.ChainOutput, "-j", string(iptablesOldPortalChain))
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ipt.FlushChain(iptables.TableNAT, iptablesOldPortalChain)
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ipt.DeleteChain(iptables.TableNAT, iptablesOldPortalChain)
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}
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// Flush all of our custom iptables rules.
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func iptablesFlush(ipt iptables.Interface) error {
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return ipt.FlushChain(iptables.TableNAT, iptablesProxyChain)
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el := []error{}
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if err := ipt.FlushChain(iptables.TableNAT, iptablesContainerPortalChain); err != nil {
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el = append(el, err)
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}
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if err := ipt.FlushChain(iptables.TableNAT, iptablesHostPortalChain); err != nil {
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el = append(el, err)
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}
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if len(el) != 0 {
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glog.Errorf("Some errors flushing old iptables portals: %v", el)
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}
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return util.SliceToError(el)
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}
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// Used below.
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@@ -600,8 +659,8 @@ var localhostIPv4 = net.ParseIP("127.0.0.1")
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var zeroIPv6 = net.ParseIP("::0")
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var localhostIPv6 = net.ParseIP("::1")
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// Build a slice of iptables args for a portal rule.
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func iptablesPortalArgs(destIP net.IP, destPort int, protocol api.Protocol, proxyIP net.IP, proxyPort int, service string) []string {
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// Build a slice of iptables args that are common to from-container and from-host portal rules.
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func iptablesCommonPortalArgs(destIP net.IP, destPort int, protocol api.Protocol, service string) []string {
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// This list needs to include all fields as they are eventually spit out
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// by iptables-save. This is because some systems do not support the
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// 'iptables -C' arg, and so fall back on parsing iptables-save output.
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@@ -618,14 +677,34 @@ func iptablesPortalArgs(destIP net.IP, destPort int, protocol api.Protocol, prox
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"-d", fmt.Sprintf("%s/32", destIP.String()),
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"--dport", fmt.Sprintf("%d", destPort),
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}
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// This is tricky. If the proxy is bound (see Proxier.listenAddress)
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// to 0.0.0.0 ("any interface") or 127.0.0.1, we can use REDIRECT,
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// which will bring packets back to the host's loopback interface. If
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// the proxy is bound to any other interface, then it is not listening
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// on the hosts's loopback, so we have to use DNAT to that specific
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// IP. We can not simply use DNAT to 127.0.0.1 in the first case
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// because from within a container, 127.0.0.1 is the container's
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// loopback interface, not the host's.
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return args
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}
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// Build a slice of iptables args for a from-container portal rule.
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func (proxier *Proxier) iptablesContainerPortalArgs(destIP net.IP, destPort int, protocol api.Protocol, proxyIP net.IP, proxyPort int, service string) []string {
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args := iptablesCommonPortalArgs(destIP, destPort, protocol, service)
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// This is tricky.
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//
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// If the proxy is bound (see Proxier.listenIP) to 0.0.0.0 ("any
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// interface") we want to use REDIRECT, which sends traffic to the
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// "primary address of the incoming interface" which means the container
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// bridge, if there is one. When the response comes, it comes from that
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// same interface, so the NAT matches and the response packet is
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// correct. This matters for UDP, since there is no per-connection port
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// number.
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//
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// The alternative would be to use DNAT, except that it doesn't work
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// (empirically):
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// * DNAT to 127.0.0.1 = Packets just disappear - this seems to be a
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// well-known limitation of iptables.
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// * DNAT to eth0's IP = Response packets come from the bridge, which
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// breaks the NAT, and makes things like DNS not accept them. If
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// this could be resolved, it would simplify all of this code.
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//
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// If the proxy is bound to a specific IP, then we have to use DNAT to
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// that IP. Unlike the previous case, this works because the proxy is
|
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|
// ONLY listening on that IP, not the bridge.
|
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|
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|
//
|
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|
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|
// Why would anyone bind to an address that is not inclusive of
|
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|
|
// localhost? Apparently some cloud environments have their public IP
|
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|
@@ -635,8 +714,10 @@ func iptablesPortalArgs(destIP net.IP, destPort int, protocol api.Protocol, prox
|
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|
// Unfortunately, I don't know of any way to listen on some (N > 1)
|
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|
|
// interfaces but not ALL interfaces, short of doing it manually, and
|
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|
// this is simpler than that.
|
|
|
|
|
if proxyIP.Equal(zeroIPv4) || proxyIP.Equal(zeroIPv6) ||
|
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|
|
|
proxyIP.Equal(localhostIPv4) || proxyIP.Equal(localhostIPv6) {
|
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|
|
|
//
|
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|
|
|
// If the proxy is bound to localhost only, all of this is broken. Not
|
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|
// allowed.
|
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|
|
|
if proxyIP.Equal(zeroIPv4) || proxyIP.Equal(zeroIPv6) {
|
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|
|
|
// TODO: Can we REDIRECT with IPv6?
|
|
|
|
|
args = append(args, "-j", "REDIRECT", "--to-ports", fmt.Sprintf("%d", proxyPort))
|
|
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|
|
} else {
|
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|
@@ -645,3 +726,72 @@ func iptablesPortalArgs(destIP net.IP, destPort int, protocol api.Protocol, prox
|
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|
}
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|
|
return args
|
|
|
|
|
}
|
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|
|
// Build a slice of iptables args for a from-host portal rule.
|
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|
|
func (proxier *Proxier) iptablesHostPortalArgs(destIP net.IP, destPort int, protocol api.Protocol, proxyIP net.IP, proxyPort int, service string) []string {
|
|
|
|
|
args := iptablesCommonPortalArgs(destIP, destPort, protocol, service)
|
|
|
|
|
|
|
|
|
|
// This is tricky.
|
|
|
|
|
//
|
|
|
|
|
// If the proxy is bound (see Proxier.listenIP) to 0.0.0.0 ("any
|
|
|
|
|
// interface") we want to do the same as from-container traffic and use
|
|
|
|
|
// REDIRECT. Except that it doesn't work (empirically). REDIRECT on
|
|
|
|
|
// localpackets sends the traffic to localhost (special case, but it is
|
|
|
|
|
// documented) but the response comes from the eth0 IP (not sure why,
|
|
|
|
|
// truthfully), which makes DNS unhappy.
|
|
|
|
|
//
|
|
|
|
|
// So we have to use DNAT. DNAT to 127.0.0.1 can't work for the same
|
|
|
|
|
// reason.
|
|
|
|
|
//
|
|
|
|
|
// So we do our best to find an interface that is not a loopback and
|
|
|
|
|
// DNAT to that. This works (again, empirically).
|
|
|
|
|
//
|
|
|
|
|
// If the proxy is bound to a specific IP, then we have to use DNAT to
|
|
|
|
|
// that IP. Unlike the previous case, this works because the proxy is
|
|
|
|
|
// ONLY listening on that IP, not the bridge.
|
|
|
|
|
//
|
|
|
|
|
// If the proxy is bound to localhost only, this should work, but we
|
|
|
|
|
// don't allow it for now.
|
|
|
|
|
if proxyIP.Equal(zeroIPv4) || proxyIP.Equal(zeroIPv6) {
|
|
|
|
|
proxyIP = proxier.hostIP
|
|
|
|
|
}
|
|
|
|
|
// TODO: Can we DNAT with IPv6?
|
|
|
|
|
args = append(args, "-j", "DNAT", "--to-destination", net.JoinHostPort(proxyIP.String(), strconv.Itoa(proxyPort)))
|
|
|
|
|
return args
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
func chooseHostInterface() (net.IP, error) {
|
|
|
|
|
intfs, err := net.Interfaces()
|
|
|
|
|
if err != nil {
|
|
|
|
|
return nil, err
|
|
|
|
|
}
|
|
|
|
|
i := 0
|
|
|
|
|
for i = range intfs {
|
|
|
|
|
if flagsSet(intfs[i].Flags, net.FlagUp) && flagsClear(intfs[i].Flags, net.FlagLoopback|net.FlagPointToPoint) {
|
|
|
|
|
// This interface should suffice.
|
|
|
|
|
break
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
if i == len(intfs) {
|
|
|
|
|
return nil, err
|
|
|
|
|
}
|
|
|
|
|
glog.V(2).Infof("Choosing interface %s for from-host portals", intfs[i].Name)
|
|
|
|
|
addrs, err := intfs[i].Addrs()
|
|
|
|
|
if err != nil {
|
|
|
|
|
return nil, err
|
|
|
|
|
}
|
|
|
|
|
glog.V(2).Infof("Interface %s = %s", intfs[i].Name, addrs[0].String())
|
|
|
|
|
ip, _, err := net.ParseCIDR(addrs[0].String())
|
|
|
|
|
if err != nil {
|
|
|
|
|
return nil, err
|
|
|
|
|
}
|
|
|
|
|
return ip, nil
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
func flagsSet(flags net.Flags, test net.Flags) bool {
|
|
|
|
|
return flags&test != 0
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
func flagsClear(flags net.Flags, test net.Flags) bool {
|
|
|
|
|
return flags&test == 0
|
|
|
|
|
}
|
|
|
|
|