plugin/secondary: serve catalog member zones (#8230)

Signed-off-by: houyuwushang <liuluoqianqiu@outlook.com>

plugin/file/file.go

@@ -24,11 +24,15 @@ type (
 		Next plugin.Handler
 		Zones
 		Xfer *transfer.Transfer
+		ZoneLookupFunc
 		TransferInFunc
 
 		Fall fall.F
 	}
 
+	// ZoneLookupFunc looks up the authoritative zone for qname.
+	ZoneLookupFunc func(qname string) (zone string, z *Zone, ok bool)
+
 	// Zones maps zone names to a *Zone.
 	Zones struct {
 		Z     map[string]*Zone // A map mapping zone (origin) to the Zone's data
@@ -41,9 +45,8 @@ func (f File) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 	state := request.Request{W: w, Req: r}
 
 	qname := state.Name()
-	// TODO(miek): match the qname better in the map
-	zone := plugin.Zones(f.Zones.Names).Matches(qname)
-	if zone == "" {
+	zone, z, ok := f.lookupZone(qname)
+	if !ok {
 		// If no next plugin is configured, it's more correct to return REFUSED as file acts as an authoritative server
 		if f.Next == nil {
 			return dns.RcodeRefused, nil
@@ -51,8 +54,7 @@ func (f File) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 		return plugin.NextOrFailure(f.Name(), f.Next, ctx, w, r)
 	}
 
-	z, ok := f.Z[zone]
-	if !ok || z == nil {
+	if z == nil {
 		return dns.RcodeServerFailure, nil
 	}
 
@@ -134,6 +136,22 @@ func (f File) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (i
 // Name implements the Handler interface.
 func (f File) Name() string { return "file" }
 
+func (f File) lookupZone(qname string) (string, *Zone, bool) {
+	if f.ZoneLookupFunc != nil {
+		return f.ZoneLookupFunc(qname)
+	}
+	// TODO(miek): match the qname better in the map
+	zone := plugin.Zones(f.Zones.Names).Matches(qname)
+	if zone == "" {
+		return "", nil, false
+	}
+	z, ok := f.Z[zone]
+	if !ok {
+		return zone, nil, true
+	}
+	return zone, z, true
+}
+
 func (f File) transferIn(z *Zone, t *transfer.Transfer) error {
 	if f.TransferInFunc != nil {
 		return f.TransferInFunc(z, t)

plugin/file/xfr.go

@@ -9,8 +9,8 @@ import (
 
 // Transfer implements the transfer.Transfer interface.
 func (f File) Transfer(zone string, serial uint32) (<-chan []dns.RR, error) {
-	z, ok := f.Z[zone]
-	if !ok || z == nil {
+	matched, z, ok := f.lookupZone(zone)
+	if !ok || matched != zone || z == nil {
 		return nil, transfer.ErrNotAuthoritative
 	}
 	return z.Transfer(serial)

plugin/file/xfr_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
 	"github.com/coredns/coredns/plugin/test"
+	"github.com/coredns/coredns/plugin/transfer"
 
 	"github.com/miekg/dns"
 )
@@ -70,3 +71,15 @@ func TestAXFRWithOutTransferPlugin(t *testing.T) {
 		t.Errorf("Expecting REFUSED, got %d", code)
 	}
 }
+
+func TestTransferRequiresExactZone(t *testing.T) {
+	zone, err := Parse(strings.NewReader(dbMiekNL), testzone, "stdin", 0)
+	if err != nil {
+		t.Fatalf("Expected no error when reading zone, got %q", err)
+	}
+
+	fm := File{Zones: Zones{Z: map[string]*Zone{testzone: zone}, Names: []string{testzone}}}
+	if _, err := fm.Transfer("www."+testzone, 0); err != transfer.ErrNotAuthoritative {
+		t.Fatalf("expected ErrNotAuthoritative for subdomain transfer, got %v", err)
+	}
+}