Move DNS utils into their own file

server/dns.go

@@ -0,0 +1,30 @@
+package weavedns
+
+import (
+	"github.com/miekg/dns"
+	"net"
+)
+
+const (
+	localTTL uint32 = 300 // somewhat arbitrary; we don't expect anyone
+	// downstream to cache results
+)
+
+func makeDNSReply(r *dns.Msg, name string, qtype uint16, addrs []net.IP) *dns.Msg {
+	m := new(dns.Msg)
+	m.SetReply(r)
+	m.RecursionAvailable = true
+	hdr := dns.RR_Header{Name: name, Rrtype: qtype, Class: dns.ClassINET, Ttl: localTTL}
+	for _, addr := range addrs {
+		if qtype == dns.TypeA {
+			if ip4 := addr.To4(); ip4 != nil {
+				m.Answer = append(m.Answer, &dns.A{hdr, addr})
+			}
+		} else if qtype == dns.TypeAAAA {
+			if ip4 := addr.To4(); ip4 == nil {
+				m.Answer = append(m.Answer, &dns.AAAA{hdr, addr})
+			}
+		}
+	}
+	return m
+}

server/mdns_server.go

@@ -11,11 +11,6 @@ type MDNSServer struct {
 	zone       Zone
 }
 
-const (
-	localTTL uint32 = 300 // somewhat arbitrary; we don't expect anyone
-	// downstream to cache results
-)
-
 func NewMDNSServer(zone Zone) (*MDNSServer, error) {
 	// 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.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: 0})
@@ -27,25 +22,6 @@ func NewMDNSServer(zone Zone) (*MDNSServer, error) {
 	return retval, nil
 }
 
-func makeDNSReply(r *dns.Msg, name string, qtype uint16, addrs []net.IP) *dns.Msg {
-	m := new(dns.Msg)
-	m.SetReply(r)
-	m.RecursionAvailable = true
-	hdr := dns.RR_Header{Name: name, Rrtype: qtype, Class: dns.ClassINET, Ttl: localTTL}
-	for _, addr := range addrs {
-		if qtype == dns.TypeA {
-			if ip4 := addr.To4(); ip4 != nil {
-				m.Answer = append(m.Answer, &dns.A{hdr, addr})
-			}
-		} else if qtype == dns.TypeAAAA {
-			if ip4 := addr.To4(); ip4 == nil {
-				m.Answer = append(m.Answer, &dns.AAAA{hdr, addr})
-			}
-		}
-	}
-	return m
-}
-
 // Return true if testaddr is a UDP address with IP matching my local i/f
 func (s *MDNSServer) addrIsLocal(testaddr net.Addr) bool {
 	if udpaddr, ok := testaddr.(*net.UDPAddr); ok {