Parse reverse address lookup IPs in the Zone

.. rather than making clients of the zone do it. At the minute there's
only one call site, but soon there will be more.

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)
@@ -77,19 +73,14 @@ func rdnsHandler(zone Zone, mdnsClient *MDNSClient) dns.HandlerFunc {
 		q := r.Question[0]
 		Debug.Printf("Local rdns 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)
-					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
-				}
+			if name, err := zone.ReverseLookupLocal(q.Name); err == nil {
+				Debug.Printf("Found name: %s", name)
+				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
 			}
 		}
 	}

nameserver/zone.go

@@ -2,16 +2,24 @@ 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 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)
+	ReverseLookupLocal(inaddr string) (string, error)
 }
 
 type Record struct {
@@ -60,15 +68,23 @@ 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 {