Interfaces for the mDNS client and server

nameserver/mdns.go

@@ -0,0 +1,28 @@
+package nameserver
+
+import "net"
+
+// A basic mDNS service
+type ZoneMDNS interface {
+	// Start the service
+	Start(*net.Interface) error
+	// Stop the service
+	Stop() error
+}
+
+// A mDNS server
+type ZoneMDNSServer interface {
+	ZoneMDNS
+	// Return the Zone database used by the server
+	Zone() Zone
+}
+
+// A mDNS client interface
+type ZoneMDNSClient interface {
+	ZoneMDNS
+	ZoneLookup
+	// Perform an insistent lookup for a name
+	InsistentLookupName(name string) ([]ZoneRecord, error)
+	// Perform an insistent lookup for a reverse address
+	InsistentLookupInaddr(inaddr string) ([]ZoneRecord, error)
+}

nameserver/mdns_server.go

@@ -11,13 +11,14 @@ type MDNSServer struct {
 	sendconn   *net.UDPConn
 	srv        *dns.Server
 	zone       Zone
+	allowLocal bool
 	running    bool
 }
 
 // Create a new mDNS server
 // Nothing will be done (including port bindings) until you `Start()` the server
-func NewMDNSServer(zone Zone) (*MDNSServer, error) {
-	return &MDNSServer{zone: zone}, nil
+func NewMDNSServer(zone Zone, local bool) (*MDNSServer, error) {
+	return &MDNSServer{zone: zone, allowLocal: local}, nil
 }
 
 // Return true if testaddr is a UDP address with IP matching my local i/f
@@ -112,6 +113,12 @@ func (s *MDNSServer) makeHandler(qtype uint16, lookup LookupFunc) dns.HandlerFun
 		// assumption that the client wouldn't ask if it already knew
 		// the answer, and if it does ask, it'll be happy to get an
 		// answer.
+		remoteAddr := rw.RemoteAddr()
+		if s.addrIsLocal(remoteAddr) && !s.allowLocal {
+			Debug.Printf("[mdns] srv: mDNS query from local host ('%s'): ignored", remoteAddr)
+			return
+		}
+
 		// TODO: use any Answer in the query for adding records in the Zone database...
 		if len(r.Answer) == 0 && len(r.Question) > 0 {
 			q := &r.Question[0]

nameserver/mdns_server_test.go

@@ -20,7 +20,7 @@ func TestServerSimpleQuery(t *testing.T) {
 	Info.Println("TestServerSimpleQuery starting")
 
 	mzone := newMockedZoneWithRecords([]ZoneRecord{testRecord1, testRecord2})
-	mdnsServer, err := NewMDNSServer(mzone)
+	mdnsServer, err := NewMDNSServer(mzone, true)
 	wt.AssertNoErr(t, err)
 	err = mdnsServer.Start(nil)
 	wt.AssertNoErr(t, err)

nameserver/server.go

@@ -120,7 +120,7 @@ func NewDNSServer(config DNSServerConfig, zone Zone, iface *net.Interface) (s *D
 	if err != nil {
 		return
 	}
-	s.mdnsSrv, err = NewMDNSServer(s.Zone)
+	s.mdnsSrv, err = NewMDNSServer(s.Zone, false)
 	if err != nil {
 		return
 	}