Merge pull request #77523 from andrewsykim/fix-xlb-from-local

pkg/proxy/iptables/proxier.go

@@ -1220,6 +1220,16 @@ func (proxier *Proxier) syncProxyRules() {
 			continue
 		}
 
+		// For LBs with externalTrafficPolicy=Local, we need to re-route any local traffic to the service chain masqueraded.
+		// Masqueraded traffic in this scenario is okay since source IP preservation only applies to external traffic anyways.
+		args = append(args[:0], "-A", string(svcXlbChain))
+		writeLine(proxier.natRules, append(args,
+			"-m", "comment", "--comment", fmt.Sprintf(`"masquerade LOCAL traffic for %s LB IP"`, svcNameString),
+			"-m", "addrtype", "--src-type", "LOCAL", "-j", string(KubeMarkMasqChain))...)
+		writeLine(proxier.natRules, append(args,
+			"-m", "comment", "--comment", fmt.Sprintf(`"route LOCAL traffic for %s LB IP to service chain"`, svcNameString),
+			"-m", "addrtype", "--src-type", "LOCAL", "-j", string(svcChain))...)
+
 		// First rule in the chain redirects all pod -> external VIP traffic to the
 		// Service's ClusterIP instead. This happens whether or not we have local
 		// endpoints; only if clusterCIDR is specified

pkg/proxy/iptables/proxier_test.go

@@ -424,6 +424,18 @@ func hasJump(rules []iptablestest.Rule, destChain, destIP string, destPort int)
 	return match
 }
 
+func hasSrcType(rules []iptablestest.Rule, srcType string) bool {
+	for _, r := range rules {
+		if r[iptablestest.SrcType] != srcType {
+			continue
+		}
+
+		return true
+	}
+
+	return false
+}
+
 func TestHasJump(t *testing.T) {
 	testCases := map[string]struct {
 		rules     []iptablestest.Rule
@@ -942,7 +954,6 @@ func TestOnlyLocalNodePorts(t *testing.T) {
 }
 
 func onlyLocalNodePorts(t *testing.T, fp *Proxier, ipt *iptablestest.FakeIPTables) {
-	shouldLBTOSVCRuleExist := len(fp.clusterCIDR) > 0
 	svcIP := "10.20.30.41"
 	svcPort := 80
 	svcNodePort := 3001
@@ -1018,12 +1029,8 @@ func onlyLocalNodePorts(t *testing.T, fp *Proxier, ipt *iptablestest.FakeIPTable
 	if hasJump(lbRules, nonLocalEpChain, "", 0) {
 		errorf(fmt.Sprintf("Found jump from lb chain %v to non-local ep %v", lbChain, epStrLocal), lbRules, t)
 	}
-	if hasJump(lbRules, svcChain, "", 0) != shouldLBTOSVCRuleExist {
-		prefix := "Did not find "
-		if !shouldLBTOSVCRuleExist {
-			prefix = "Found "
-		}
-		errorf(fmt.Sprintf("%s jump from lb chain %v to svc %v", prefix, lbChain, svcChain), lbRules, t)
+	if !hasJump(lbRules, svcChain, "", 0) || !hasSrcType(lbRules, "LOCAL") {
+		errorf(fmt.Sprintf("Did not find jump from lb chain %v to svc %v with src-type LOCAL", lbChain, svcChain), lbRules, t)
 	}
 	if !hasJump(lbRules, localEpChain, "", 0) {
 		errorf(fmt.Sprintf("Didn't find jump from lb chain %v to local ep %v", lbChain, epStrLocal), lbRules, t)

pkg/util/iptables/testing/fake.go

@@ -34,6 +34,7 @@ const (
 	ToDest      = "--to-destination "
 	Recent      = "recent "
 	MatchSet    = "--match-set "
+	SrcType     = "--src-type "
 )
 
 type Rule map[string]string
@@ -113,7 +114,7 @@ func (f *FakeIPTables) GetRules(chainName string) (rules []Rule) {
 	for _, l := range strings.Split(string(f.Lines), "\n") {
 		if strings.Contains(l, fmt.Sprintf("-A %v", chainName)) {
 			newRule := Rule(map[string]string{})
-			for _, arg := range []string{Destination, Source, DPort, Protocol, Jump, ToDest, Recent, MatchSet} {
+			for _, arg := range []string{Destination, Source, DPort, Protocol, Jump, ToDest, Recent, MatchSet, SrcType} {
 				tok := getToken(l, arg)
 				if tok != "" {
 					newRule[arg] = tok