temp

cmd/containerboot/ingressservices.go

@@ -247,6 +247,7 @@ func ensureIngressRulesAdded(cfgs map[string]ingressservices.Config, nfr linuxfw
 	}
 	return nil
 }
+
 func ensureIngressRulesDeleted(cfgs map[string]ingressservices.Config, nfr linuxfw.NetfilterRunner) error {
 	for serviceName, cfg := range cfgs {
 		f := func(svcName string, vipIP, clusterIP netip.Addr) error {

util/linuxfw/nftables_for_svcs.go

@@ -243,3 +243,61 @@ func protoFromString(s string) (uint8, error) {
 		return 0, fmt.Errorf("unrecognized protocol: %q", s)
 	}
 }
+
+func (n *nftablesRunner) EnsureDNATRuleForSvc(svc string, origDst, dst netip.Addr) error {
+	t, ch, err := n.ensurePreroutingChain(origDst)
+	if err != nil {
+		return fmt.Errorf("error ensuring chain for %s: %w", svc, err)
+	}
+	meta := svcRuleMeta(svc, origDst, dst)
+	rule, err := n.findRuleByMetadata(t, ch, meta)
+	if err != nil {
+		return fmt.Errorf("error looking up rule: %w", err)
+	}
+	if rule != nil {
+		return nil
+	}
+	rule = dnatRuleForChain(t, ch, origDst, dst, meta)
+	n.conn.InsertRule(rule)
+	return n.conn.Flush()
+}
+
+func (n *nftablesRunner) DeleteDNATRuleForSvc(svcName string, origDst, dst netip.Addr) error {
+	table, err := n.getNFTByAddr(origDst)
+	if err != nil {
+		return fmt.Errorf("error setting up nftables for IP family of %s: %w", origDst, err)
+	}
+	t, err := getTableIfExists(n.conn, table.Proto, "nat")
+	if err != nil {
+		return fmt.Errorf("error checking if nat table exists: %w", err)
+	}
+	if t == nil {
+		return nil
+	}
+	ch, err := getChainFromTable(n.conn, t, "PREROUTING")
+	if errors.Is(err, errorChainNotFound{tableName: "nat", chainName: "PREROUTING"}) {
+		return nil
+	}
+	if err != nil {
+		return fmt.Errorf("error checking if chain PREROUTING exists: %w", err)
+	}
+	meta := svcRuleMeta(svcName, origDst, dst)
+	rule, err := n.findRuleByMetadata(t, ch, meta)
+	if err != nil {
+		return fmt.Errorf("error checking if rule exists: %w", err)
+	}
+	if rule == nil {
+		return nil
+	}
+	if err := n.conn.DelRule(rule); err != nil {
+		return fmt.Errorf("error deleting rule: %w", err)
+	}
+	return n.conn.Flush()
+}
+
+// svcRuleMeta generates metadata for a rule.
+// This metadata can then be used to find the rule.
+// https://github.com/google/nftables/issues/48
+func svcRuleMeta(svcName string, origDst, dst netip.Addr) []byte {
+	return []byte(fmt.Sprintf("svc:%s,VIP:%s,ClusterIP:%s", svcName, origDst.String(), dst.String()))
+}

util/linuxfw/nftables_runner.go

@@ -107,6 +107,12 @@ func (n *nftablesRunner) AddDNATRule(origDst netip.Addr, dst netip.Addr) error {
 	if err != nil {
 		return err
 	}
+	rule := dnatRuleForChain(nat, preroutingCh, origDst, dst, nil)
+	n.conn.InsertRule(rule)
+	return n.conn.Flush()
+}
+
+func dnatRuleForChain(t *nftables.Table, ch *nftables.Chain, origDst, dst netip.Addr, meta []byte) *nftables.Rule {
 	var daddrOffset, fam, dadderLen uint32
 	if origDst.Is4() {
 		daddrOffset = 16
@@ -117,9 +123,9 @@ func (n *nftablesRunner) AddDNATRule(origDst netip.Addr, dst netip.Addr) error {
 		dadderLen = 16
 		fam = unix.NFPROTO_IPV6
 	}
-	dnatRule := &nftables.Rule{
-		Table: nat,
-		Chain: preroutingCh,
+	rule := &nftables.Rule{
+		Table: t,
+		Chain: ch,
 		Exprs: []expr.Any{
 			&expr.Payload{
 				DestRegister: 1,
@@ -143,8 +149,10 @@ func (n *nftablesRunner) AddDNATRule(origDst netip.Addr, dst netip.Addr) error {
 			},
 		},
 	}
-	n.conn.InsertRule(dnatRule)
-	return n.conn.Flush()
+	if len(meta) > 0 {
+		rule.UserData = meta
+	}
+	return rule
 }
 
 // DNATWithLoadBalancer currently just forwards all traffic destined for origDst
@@ -2055,10 +2063,3 @@ func snatRule(t *nftables.Table, ch *nftables.Chain, src, dst netip.Addr, meta [
 		UserData: meta,
 	}
 }
-
-func (nfr *nftablesRunner) EnsureDNATRuleForSvc(svcName string, origDst, dst netip.Addr) error {
-	return nil
-}
-func (nfr *nftablesRunner) DeleteDNATRuleForSvc(svcName string, origDst, dst netip.Addr) error {
-	return nil
-}