Merge pull request #328 from squaremo/refactor_mdns

LGTM.  Fixes #326

common/testing_utils.go

@@ -30,6 +30,18 @@ func AssertNoErr(t *testing.T, err error) {
 	}
 }
 
+func AssertEqualInt(t *testing.T, got, wanted int, desc string) {
+	if got != wanted {
+		t.Fatalf("%s: Expected %s %d but got %d", CallSite(), desc, wanted, got)
+	}
+}
+
+func AssertEqualString(t *testing.T, got, wanted string, desc string) {
+	if got != wanted {
+		t.Fatalf("%s: Expected %s '%s' but got '%s'", CallSite(), desc, wanted, got)
+	}
+}
+
 func AssertStatus(t *testing.T, got int, wanted int, desc string) {
 	if got != wanted {
 		t.Fatalf("%s: Expected %s %d but got %d", CallSite(), desc, wanted, got)
@@ -49,3 +61,10 @@ func AssertErrorType(t *testing.T, got interface{}, wanted interface{}, desc str
 		t.Fatalf("%s: Expected %s but got %s (%s)", CallSite(), wantedT.String(), gotT.String(), desc)
 	}
 }
+
+func AssertType(t *testing.T, got interface{}, wanted interface{}, desc string) {
+	gotT, wantedT := reflect.TypeOf(got), reflect.TypeOf(wanted)
+	if gotT != wantedT {
+		t.Fatalf("%s: Expected %s but got %s (%s)", CallSite(), wantedT.String(), gotT.String(), desc)
+	}
+}

nameserver/mdns_client.go

@@ -26,7 +26,7 @@ var (
 	}
 )
 
-type ResponseA struct {
+type Response struct {
 	Name string
 	Addr net.IP
 	Err  error
@@ -34,7 +34,7 @@ type ResponseA struct {
 
 type responseInfo struct {
 	timeout time.Time // if no answer by this time, give up
-	ch      chan<- *ResponseA
+	ch      chan<- *Response
 }
 
 // Represents one query that we have sent for one name.
@@ -60,7 +60,7 @@ type MDNSClient struct {
 type mDNSQueryInfo struct {
 	name       string
 	querytype  uint16
-	responseCh chan<- *ResponseA
+	responseCh chan<- *Response
 }
 
 func NewMDNSClient() (*MDNSClient, error) {
@@ -121,7 +121,7 @@ func (c *MDNSClient) Shutdown() {
 }
 
 // Async
-func (c *MDNSClient) SendQuery(name string, querytype uint16, responseCh chan<- *ResponseA) {
+func (c *MDNSClient) SendQuery(name string, querytype uint16, responseCh chan<- *Response) {
 	c.queryChan <- &MDNSInteraction{
 		code:    CSendQuery,
 		payload: mDNSQueryInfo{name, querytype, responseCh},
@@ -209,7 +209,7 @@ func (c *MDNSClient) handleSendQuery(q mDNSQueryInfo) {
 		m.RecursionDesired = false
 		buf, err := m.Pack()
 		if err != nil {
-			q.responseCh <- &ResponseA{Err: err}
+			q.responseCh <- &Response{Err: err}
 			close(q.responseCh)
 			return
 		}
@@ -218,7 +218,7 @@ func (c *MDNSClient) handleSendQuery(q mDNSQueryInfo) {
 			id:   m.Id,
 		}
 		if _, err = c.conn.WriteTo(buf, c.addr); err != nil {
-			q.responseCh <- &ResponseA{Err: err}
+			q.responseCh <- &Response{Err: err}
 			close(q.responseCh)
 			return
 		}
@@ -235,19 +235,29 @@ func (c *MDNSClient) handleSendQuery(q mDNSQueryInfo) {
 
 func (c *MDNSClient) handleResponse(r *dns.Msg) {
 	for _, answer := range r.Answer {
+		var name string
+		var res *Response
+
 		switch rr := answer.(type) {
 		case *dns.A:
-			name := rr.Hdr.Name
-			if query, found := c.inflight[name]; found {
-				for _, resp := range query.responseInfos {
-					resp.ch <- &ResponseA{Name: rr.Hdr.Name, Addr: rr.A}
-					close(resp.ch)
-				}
-				delete(c.inflight, name)
-			} else {
-				// We've received a response that didn't match a query
-				// Do we want to cache it?
+			name = rr.Hdr.Name
+			res = &Response{Addr: rr.A}
+		case *dns.PTR:
+			name = rr.Hdr.Name
+			res = &Response{Name: rr.Ptr}
+		default:
+			return
+		}
+
+		if query, found := c.inflight[name]; found {
+			for _, resp := range query.responseInfos {
+				resp.ch <- res
+				close(resp.ch)
 			}
+			delete(c.inflight, name)
+		} else {
+			// We've received a response that didn't match a query
+			// Do we want to cache it?
 		}
 	}
 }

nameserver/mdns_client_test.go

@@ -13,9 +13,27 @@ var (
 	successTestName = "test1.weave."
 	failTestName    = "test2.weave."
 	testAddr        = net.ParseIP("9.8.7.6")
+	testInAddr      = "6.7.8.9.in-addr.arpa."
 )
 
 func minimalServer(w dns.ResponseWriter, req *dns.Msg) {
+
+	sendAnswer := func(m *dns.Msg) {
+		buf, err := m.Pack()
+		checkFatal(err)
+		if buf == nil {
+			log.Fatal("Nil buffer")
+		}
+		//log.Println("minimalServer sending:", buf)
+		// This is a bit of a kludge - per the RFC we should send responses from 5353, but that doesn't seem to work
+		sendconn, err := net.DialUDP("udp", nil, ipv4Addr)
+		checkFatal(err)
+
+		_, err = sendconn.Write(buf)
+		sendconn.Close()
+		checkFatal(err)
+	}
+
 	//log.Println("minimalServer received:", req)
 	if len(req.Answer) > 0 {
 		return // Only interested in questions.
@@ -23,31 +41,24 @@ func minimalServer(w dns.ResponseWriter, req *dns.Msg) {
 	if len(req.Question) != 1 {
 		return // We only handle single-question messages
 	}
-	if req.Question[0].Name != successTestName {
-		return // This is not the DNS record you are looking for
+
+	if req.Question[0].Qtype == dns.TypeA && req.Question[0].Name == successTestName {
+		m := new(dns.Msg)
+		m.SetReply(req)
+		hdr := dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypeA,
+			Class: dns.ClassINET, Ttl: 3600}
+		a := &dns.A{hdr, testAddr}
+		m.Answer = append(m.Answer, a)
+		sendAnswer(m)
+	} else if req.Question[0].Qtype == dns.TypePTR && req.Question[0].Name == testInAddr {
+		m := new(dns.Msg)
+		m.SetReply(req)
+		hdr := dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypePTR,
+			Class: dns.ClassINET, Ttl: 3600}
+		a := &dns.PTR{hdr, successTestName}
+		m.Answer = append(m.Answer, a)
+		sendAnswer(m)
 	}
-
-	m := new(dns.Msg)
-	m.SetReply(req)
-
-	hdr := dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypeA,
-		Class: dns.ClassINET, Ttl: 3600}
-	a := &dns.A{hdr, testAddr}
-	m.Answer = append(m.Answer, a)
-
-	buf, err := m.Pack()
-	checkFatal(err)
-	if buf == nil {
-		log.Fatal("Nil buffer")
-	}
-	//log.Println("minimalServer sending:", buf)
-	// This is a bit of a kludge - per the RFC we should send responses from 5353, but that doesn't seem to work
-	sendconn, err := net.DialUDP("udp", nil, ipv4Addr)
-	checkFatal(err)
-
-	_, err = sendconn.Write(buf)
-	sendconn.Close()
-	checkFatal(err)
 }
 
 func RunLocalMulticastServer() (*dns.Server, error) {
@@ -76,14 +87,14 @@ func setup(t *testing.T) (*MDNSClient, *dns.Server, error) {
 type testContext struct {
 	receivedAddr  net.IP
 	receivedCount int
-	channel       chan *ResponseA
+	channel       chan *Response
 }
 
 func newTestContext() *testContext {
-	return &testContext{channel: make(chan *ResponseA, 4)}
+	return &testContext{channel: make(chan *Response, 4)}
 }
 
-func (c *testContext) checkResponse(t *testing.T, channelOk bool, resp *ResponseA) {
+func (c *testContext) checkResponse(t *testing.T, channelOk bool, resp *Response) {
 	if !channelOk {
 		c.channel = nil
 		return
@@ -152,3 +163,24 @@ outerloop:
 		t.Fatal("Unexpected result for", successTestName, context1.receivedAddr, context2.receivedAddr, context1.receivedCount, context2.receivedCount)
 	}
 }
+
+func TestAsLookup(t *testing.T) {
+	mdnsClient, server, _ := setup(t)
+	defer mdnsClient.Shutdown()
+	defer server.Shutdown()
+
+	ip, err := mdnsClient.LookupLocal(successTestName)
+	wt.AssertNoErr(t, err)
+	if !testAddr.Equal(ip) {
+		t.Fatalf("Returned address incorrect %s", ip)
+	}
+
+	ip, err = mdnsClient.LookupLocal("foo.example.com.")
+	wt.AssertErrorType(t, err, (*LookupError)(nil), "unknown hostname")
+
+	name, err := mdnsClient.ReverseLookupLocal(testInAddr)
+	wt.AssertNoErr(t, err)
+	if !(successTestName == name) {
+		t.Fatalf("Expected name %s, got %s", successTestName, name)
+	}
+}

nameserver/mdns_lookup.go

@@ -0,0 +1,37 @@
+package nameserver
+
+import (
+	"github.com/miekg/dns"
+	. "github.com/zettio/weave/common"
+	"net"
+)
+
+func mdnsLookup(client *MDNSClient, name string, qtype uint16) (*Response, error) {
+	channel := make(chan *Response)
+	client.SendQuery(name, qtype, channel)
+	for resp := range channel {
+		Debug.Printf("Got response name %s addr %s", resp.Name, resp.Addr)
+		if err := resp.Err; err != nil {
+			return nil, err
+		} else {
+			return resp, nil
+		}
+	}
+	return nil, LookupError(name)
+}
+
+func (client *MDNSClient) LookupLocal(name string) (net.IP, error) {
+	if r, e := mdnsLookup(client, name, dns.TypeA); r != nil {
+		return r.Addr, nil
+	} else {
+		return nil, e
+	}
+}
+
+func (client *MDNSClient) ReverseLookupLocal(inaddr string) (string, error) {
+	if r, e := mdnsLookup(client, inaddr, dns.TypePTR); r != nil {
+		return r.Name, nil
+	} else {
+		return "", e
+	}
+}

nameserver/mdns_server.go

@@ -50,24 +50,57 @@ func (s *MDNSServer) Start(ifi *net.Interface) error {
 		return err
 	}
 
-	handleMDNS := func(w dns.ResponseWriter, r *dns.Msg) {
-		// Ignore answers to other questions
-		if len(r.Answer) == 0 && len(r.Question) > 0 {
-			q := r.Question[0]
-			if ip, err := s.zone.LookupLocal(q.Name); err == nil {
-				m := makeAddressReply(r, &q, []net.IP{ip})
-				if err = s.sendResponse(m); err != nil {
-					Warning.Printf("Error writing to %s", w)
-				}
-			} else if s.addrIsLocal(w.RemoteAddr()) {
-				// ignore this - it's our own query received via multicast
+	handleLocal := s.makeHandler(dns.TypeA,
+		func(zone Lookup, r *dns.Msg, q *dns.Question) *dns.Msg {
+			if ip, err := zone.LookupLocal(q.Name); err == nil {
+				return makeAddressReply(r, q, []net.IP{ip})
 			} else {
-				Debug.Printf("Failed MDNS lookup for %s", q.Name)
+				return nil
+			}
+		})
+
+	handleReverse := s.makeHandler(dns.TypePTR,
+		func(zone Lookup, r *dns.Msg, q *dns.Question) *dns.Msg {
+			if name, err := zone.ReverseLookupLocal(q.Name); err == nil {
+				return makePTRReply(r, q, []string{name})
+			} else {
+				return nil
+			}
+		})
+
+	mux := dns.NewServeMux()
+	mux.HandleFunc(LOCAL_DOMAIN, handleLocal)
+	mux.HandleFunc(RDNS_DOMAIN, handleReverse)
+
+	go dns.ActivateAndServe(nil, conn, mux)
+	return err
+}
+
+type LookupFunc func(Lookup, *dns.Msg, *dns.Question) *dns.Msg
+
+func (s *MDNSServer) makeHandler(qtype uint16, lookup LookupFunc) dns.HandlerFunc {
+	return func(_ dns.ResponseWriter, r *dns.Msg) {
+		// Handle only questions, ignore answers. We might also ignore
+		// questions that arise locally (i.e., that come from an IP we
+		// think is local), but in the interest of avoiding
+		// complication, and easier testing, this is elided on the
+		// 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.
+		if len(r.Answer) == 0 && len(r.Question) > 0 {
+			q := &r.Question[0]
+			if q.Qtype == qtype {
+				if m := lookup(s.zone, r, q); m != nil {
+					Debug.Printf("Found local answer to mDNS query %s", q.Name)
+					if err := s.sendResponse(m); err != nil {
+						Warning.Printf("Error writing to %s", s.sendconn)
+					}
+				} else {
+					Debug.Printf("No local answer for mDNS query %s", q.Name)
+				}
 			}
 		}
 	}
-	go dns.ActivateAndServe(nil, conn, dns.HandlerFunc(handleMDNS))
-	return err
 }
 
 func (s *MDNSServer) sendResponse(m *dns.Msg) error {

nameserver/mdns_server_test.go

@@ -11,7 +11,9 @@ import (
 
 var (
 	containerID = "deadbeef"
+	testName    = "test.weave.local."
 	testAddr1   = "10.0.2.1/24"
+	testInAddr1 = "1.2.0.10.in-addr.arpa."
 )
 
 func sendQuery(name string, querytype uint16) error {
@@ -31,10 +33,13 @@ func sendQuery(name string, querytype uint16) error {
 }
 
 func TestServerSimpleQuery(t *testing.T) {
+	// The ff can be handy for debugging (obvs)
+	//wt.InitDefaultLogging(true)
+
 	log.Println("TestServerSimpleQuery starting")
 	var zone = new(ZoneDb)
 	ip, _, _ := net.ParseCIDR(testAddr1)
-	zone.AddRecord(containerID, "test.weave.", ip)
+	zone.AddRecord(containerID, testName, ip)
 
 	mdnsServer, err := NewMDNSServer(zone)
 	wt.AssertNoErr(t, err)
@@ -42,8 +47,26 @@ func TestServerSimpleQuery(t *testing.T) {
 	wt.AssertNoErr(t, err)
 
 	var receivedAddr net.IP
+	var receivedName string
+	var recvChan chan interface{}
 	receivedCount := 0
 
+	reset := func() {
+		receivedAddr = nil
+		receivedName = ""
+		receivedCount = 0
+		recvChan = make(chan interface{})
+	}
+
+	wait := func() {
+		select {
+		case <-recvChan:
+			return
+		case <-time.After(100 * time.Millisecond):
+			return
+		}
+	}
+
 	// Implement a minimal listener for responses
 	multicast, err := LinkLocalMulticastListener(nil)
 	wt.AssertNoErr(t, err)
@@ -56,8 +79,12 @@ func TestServerSimpleQuery(t *testing.T) {
 				case *dns.A:
 					receivedAddr = rr.A
 					receivedCount++
+				case *dns.PTR:
+					receivedName = rr.Ptr
+					receivedCount++
 				}
 			}
+			recvChan <- "ok"
 		}
 	}
 
@@ -67,22 +94,32 @@ func TestServerSimpleQuery(t *testing.T) {
 
 	time.Sleep(100 * time.Millisecond) // Allow for server to get going
 
-	sendQuery("test.weave.", dns.TypeA)
-
-	time.Sleep(time.Second)
+	reset()
+	sendQuery(testName, dns.TypeA)
+	wait()
 
 	if receivedCount != 1 {
-		t.Fatal("Unexpected result count for test.weave", receivedCount)
+		t.Fatalf("Unexpected result count %d for %s", receivedCount, testName)
 	}
 	if !receivedAddr.Equal(ip) {
-		t.Fatal("Unexpected result for test.weave", receivedAddr)
+		t.Fatalf("Unexpected result %s for %s", receivedAddr, testName)
 	}
 
-	receivedCount = 0
-
+	reset()
 	sendQuery("testfail.weave.", dns.TypeA)
+	wait()
 
 	if receivedCount != 0 {
-		t.Fatal("Unexpected result count for testfail.weave", receivedCount)
+		t.Fatalf("Unexpected result count %d for testfail.weave", receivedCount)
+	}
+
+	reset()
+	sendQuery(testInAddr1, dns.TypePTR)
+	wait()
+
+	if receivedCount != 1 {
+		t.Fatalf("Expected an answer to %s, got %d answers", testInAddr1, receivedCount)
+	} else if !(testName == receivedName) {
+		t.Fatalf("Expected answer %s to query for %s, got %s", testName, testInAddr1, receivedName)
 	}
 }

nameserver/server.go

@@ -9,12 +9,8 @@ import (
 
 const (
 	LOCAL_DOMAIN = "weave.local."
-	RDNS_DOMAIN  = "in-addr.arpa."
 )
 
-// +1 to also exclude a dot
-var rdnsDomainLen = len(RDNS_DOMAIN) + 1
-
 func checkFatal(e error) {
 	if e != nil {
 		Error.Fatal(e)
@@ -35,62 +31,45 @@ func makeDNSFailResponse(r *dns.Msg) *dns.Msg {
 	return m
 }
 
-func queryHandler(zone Zone, mdnsClient *MDNSClient) dns.HandlerFunc {
+func queryHandler(lookups []Lookup) dns.HandlerFunc {
 	return func(w dns.ResponseWriter, r *dns.Msg) {
 		q := r.Question[0]
-		Debug.Printf("Local query: %+v", q)
+		Debug.Printf("Query: %+v", q)
 		if q.Qtype == dns.TypeA {
-			if ip, err := zone.LookupLocal(q.Name); err == nil {
-				m := makeAddressReply(r, &q, []net.IP{ip})
-				w.WriteMsg(m)
-			} else {
-				Debug.Printf("Failed lookup for %s; sending mDNS query", q.Name)
-				// We don't know the answer; see if someone else does
-				channel := make(chan *ResponseA)
-				replies := make([]net.IP, 0)
-				go func() {
-					for resp := range channel {
-						Debug.Printf("Got address response %s to query %s addr %s", resp.Name, q.Name, resp.Addr)
-						replies = append(replies, resp.Addr)
-					}
-					var responseMsg *dns.Msg
-					if len(replies) > 0 {
-						responseMsg = makeAddressReply(r, &q, replies)
-					} else {
-						responseMsg = makeDNSFailResponse(r)
-					}
-					w.WriteMsg(responseMsg)
-				}()
-				mdnsClient.SendQuery(q.Name, dns.TypeA, channel)
+			for _, lookup := range lookups {
+				if ip, err := lookup.LookupLocal(q.Name); err == nil {
+					m := makeAddressReply(r, &q, []net.IP{ip})
+					w.WriteMsg(m)
+					return
+				}
 			}
+			Debug.Printf("Query failed for %s", q.Name)
+			w.WriteMsg(makeDNSFailResponse(r))
 		} else {
-			Warning.Printf("Local query not handled: %+v", q)
-			m := makeDNSFailResponse(r)
-			w.WriteMsg(m)
+			Warning.Printf("Query not handled: %+v", q)
+			w.WriteMsg(makeDNSFailResponse(r))
 		}
 		return
 	}
 }
 
-func rdnsHandler(zone Zone, mdnsClient *MDNSClient) dns.HandlerFunc {
+func rdnsHandler(lookups []Lookup) dns.HandlerFunc {
 	return func(w dns.ResponseWriter, r *dns.Msg) {
 		q := r.Question[0]
-		Debug.Printf("Local rdns query: %+v", q)
+		Debug.Printf("Reverse query: %+v", q)
 		if q.Qtype == dns.TypePTR {
-			if ip := net.ParseIP(q.Name[:len(q.Name)-rdnsDomainLen]); ip != nil {
-				ip4 := ip.To4()
-				revIP := []byte{ip4[3], ip4[2], ip4[1], ip4[0]}
-				Debug.Printf("Looking for address: %+v", revIP)
-				if name, err := zone.ReverseLookupLocal(revIP); err == nil {
-					Debug.Printf("Found name: %s", name)
+			for _, lookup := range lookups {
+				if name, err := lookup.ReverseLookupLocal(q.Name); err == nil {
 					m := makePTRReply(r, &q, []string{name})
 					w.WriteMsg(m)
-				} else {
-					Debug.Printf("Failed lookup for %s; sending mDNS query", q.Name)
-					// We don't know the answer; see if someone else does
-					// TODO
+					return
 				}
 			}
+			Debug.Printf("Reverse query failed for %s", q.Name)
+			w.WriteMsg(makeDNSFailResponse(r))
+		} else {
+			Warning.Printf("Reverse query not handled: %+v", q)
+			w.WriteMsg(makeDNSFailResponse(r))
 		}
 	}
 }
@@ -119,9 +98,7 @@ func notUsHandler() dns.HandlerFunc {
 	}
 }
 
-func StartServer(zone Zone, iface *net.Interface, dnsPort int, httpPort int, wait int) error {
-	go ListenHttp(LOCAL_DOMAIN, zone, httpPort)
-
+func StartServer(zone Zone, iface *net.Interface, dnsPort int, wait int) error {
 	mdnsClient, err := NewMDNSClient()
 	checkFatal(err)
 
@@ -134,8 +111,8 @@ func StartServer(zone Zone, iface *net.Interface, dnsPort int, httpPort int, wai
 	checkFatal(err)
 
 	LocalServeMux := dns.NewServeMux()
-	LocalServeMux.HandleFunc(LOCAL_DOMAIN, queryHandler(zone, mdnsClient))
-	LocalServeMux.HandleFunc(RDNS_DOMAIN, rdnsHandler(zone, mdnsClient))
+	LocalServeMux.HandleFunc(LOCAL_DOMAIN, queryHandler([]Lookup{zone, mdnsClient}))
+	LocalServeMux.HandleFunc(RDNS_DOMAIN, rdnsHandler([]Lookup{zone, mdnsClient}))
 	LocalServeMux.HandleFunc(".", notUsHandler())
 
 	mdnsServer, err := NewMDNSServer(zone)

nameserver/server_test.go

@@ -0,0 +1,78 @@
+package nameserver
+
+import (
+	"fmt"
+	"github.com/miekg/dns"
+	wt "github.com/zettio/weave/common"
+	"net"
+	"testing"
+	"time"
+)
+
+func TestDNSServer(t *testing.T) {
+	const (
+		port            = 17625
+		successTestName = "test1.weave.local."
+		failTestName    = "test2.weave.local."
+		nonLocalName    = "weave.works."
+		testAddr1       = "10.0.2.1"
+		testRDNSsuccess = "1.2.0.10.in-addr.arpa."
+		testRDNSfail    = "4.3.2.1.in-addr.arpa."
+	)
+	dnsAddr := fmt.Sprintf("localhost:%d", port)
+	testCIDR1 := testAddr1 + "/24"
+
+	wt.InitDefaultLogging(true)
+	var zone = new(ZoneDb)
+	ip, _, _ := net.ParseCIDR(testCIDR1)
+	zone.AddRecord(containerID, successTestName, ip)
+
+	go StartServer(zone, nil, port, 0)
+	time.Sleep(100 * time.Millisecond) // Allow sever goroutine to start
+
+	c := new(dns.Client)
+	m := new(dns.Msg)
+	m.SetQuestion(successTestName, dns.TypeA)
+	m.RecursionDesired = true
+	r, _, err := c.Exchange(m, dnsAddr)
+	wt.AssertNoErr(t, err)
+	wt.AssertStatus(t, r.Rcode, dns.RcodeSuccess, "DNS response code")
+	wt.AssertEqualInt(t, len(r.Answer), 1, "Number of answers")
+	wt.AssertType(t, r.Answer[0], (*dns.A)(nil), "DNS record")
+	wt.AssertEqualString(t, r.Answer[0].(*dns.A).A.String(), testAddr1, "IP address")
+
+	m.SetQuestion(failTestName, dns.TypeA)
+	r, _, err = c.Exchange(m, dnsAddr)
+	wt.AssertNoErr(t, err)
+	wt.AssertStatus(t, r.Rcode, dns.RcodeNameError, "DNS response code")
+	wt.AssertEqualInt(t, len(r.Answer), 0, "Number of answers")
+
+	m.SetQuestion(testRDNSsuccess, dns.TypePTR)
+	r, _, err = c.Exchange(m, dnsAddr)
+	wt.AssertNoErr(t, err)
+	wt.AssertStatus(t, r.Rcode, dns.RcodeSuccess, "DNS response code")
+	wt.AssertEqualInt(t, len(r.Answer), 1, "Number of answers")
+	wt.AssertType(t, r.Answer[0], (*dns.PTR)(nil), "DNS record")
+	wt.AssertEqualString(t, r.Answer[0].(*dns.PTR).Ptr, successTestName, "IP address")
+	m.SetQuestion(testRDNSfail, dns.TypePTR)
+	r, _, err = c.Exchange(m, dnsAddr)
+	wt.AssertNoErr(t, err)
+	wt.AssertStatus(t, r.Rcode, dns.RcodeNameError, "DNS response code")
+	wt.AssertEqualInt(t, len(r.Answer), 0, "Number of answers")
+
+	// This should fail because we don't handle MX records
+	m.SetQuestion(successTestName, dns.TypeMX)
+	r, _, err = c.Exchange(m, dnsAddr)
+	wt.AssertNoErr(t, err)
+	wt.AssertStatus(t, r.Rcode, dns.RcodeNameError, "DNS response code")
+	wt.AssertEqualInt(t, len(r.Answer), 0, "Number of answers")
+
+	// This non-local query should fail because we don't handle MX records
+	m.SetQuestion(nonLocalName, dns.TypeMX)
+	r, _, err = c.Exchange(m, dnsAddr)
+	wt.AssertNoErr(t, err)
+	wt.AssertStatus(t, r.Rcode, dns.RcodeNameError, "DNS response code")
+	wt.AssertEqualInt(t, len(r.Answer), 0, "Number of answers")
+
+	// Not testing MDNS functionality of server here (yet)
+}

nameserver/zone.go

@@ -2,16 +2,28 @@ package nameserver
 
 import (
 	"github.com/miekg/dns"
+	. "github.com/zettio/weave/common"
 	"net"
 	"sync"
 )
 
+const (
+	RDNS_DOMAIN = "in-addr.arpa."
+)
+
+// +1 to also exclude a dot
+var rdnsDomainLen = len(RDNS_DOMAIN) + 1
+
+type Lookup interface {
+	LookupLocal(name string) (net.IP, error)
+	ReverseLookupLocal(inaddr string) (string, error)
+}
+
 type Zone interface {
 	AddRecord(ident string, name string, ip net.IP) error
 	DeleteRecord(ident string, ip net.IP) error
 	DeleteRecordsFor(ident string) error
-	LookupLocal(name string) (net.IP, error)
-	ReverseLookupLocal(ip net.IP) (string, error)
+	Lookup
 }
 
 type Record struct {
@@ -60,15 +72,23 @@ func (zone *ZoneDb) LookupLocal(name string) (net.IP, error) {
 	return nil, LookupError(name)
 }
 
-func (zone *ZoneDb) ReverseLookupLocal(ip net.IP) (string, error) {
-	zone.mx.RLock()
-	defer zone.mx.RUnlock()
-	for _, r := range zone.recs {
-		if r.IP.Equal(ip) {
-			return r.Name, nil
+func (zone *ZoneDb) ReverseLookupLocal(inaddr string) (string, error) {
+	if revIP := net.ParseIP(inaddr[:len(inaddr)-rdnsDomainLen]); revIP != nil {
+		revIP4 := revIP.To4()
+		ip := []byte{revIP4[3], revIP4[2], revIP4[1], revIP4[0]}
+		Debug.Printf("Looking for address: %+v", ip)
+		zone.mx.RLock()
+		defer zone.mx.RUnlock()
+		for _, r := range zone.recs {
+			if r.IP.Equal(ip) {
+				return r.Name, nil
+			}
 		}
+		return "", LookupError(inaddr)
+	} else {
+		Warning.Printf("Asked to reverse lookup %s", inaddr)
+		return "", LookupError(inaddr)
 	}
-	return "", LookupError(ip.String())
 }
 
 func (zone *ZoneDb) AddRecord(ident string, name string, ip net.IP) error {

nameserver/zone_test.go

@@ -35,7 +35,7 @@ func TestZone(t *testing.T) {
 	}
 
 	// See if we can find the address by IP.
-	foundName, err := zone.ReverseLookupLocal(ip)
+	foundName, err := zone.ReverseLookupLocal("1.2.0.10.in-addr.arpa.")
 	wt.AssertNoErr(t, err)
 
 	if foundName != successTestName {

weavedns/main.go

@@ -63,7 +63,8 @@ func main() {
 		}
 	}
 
-	err := weavedns.StartServer(zone, iface, dnsPort, httpPort, wait)
+	go weavedns.ListenHttp(weavedns.LOCAL_DOMAIN, zone, httpPort)
+	err := weavedns.StartServer(zone, iface, dnsPort, wait)
 	if err != nil {
 		Error.Fatal("Failed to start server", err)
 	}