add syncNetworkUtil in kubelet

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)
+}