Relax isSupportedIPv6 to just no mapped

conn.go

@@ -1049,18 +1049,10 @@ func ipFromAnswerHeader(a dnsmessage.ResourceHeader, p dnsmessage.Parser) (ip []
 	return
 }
 
-// The conditions of invalidation written below are defined in
-// https://tools.ietf.org/html/rfc8445#section-5.1.1.1
 func isSupportedIPv6(ip net.IP, ipv6Only bool) bool {
 	if len(ip) != net.IPv6len ||
-		isZeros(ip[0:12]) || // !(IPv4-compatible IPv6)
-		// IPv4-mapped IPv6 addresses SHOULD NOT be included in the address
-		// candidates unless the application using ICE does not support IPv4
-		// (i.e., it is an IPv6-only application
-		(!ipv6Only && isZeros(ip[0:10]) && ip[10] == 0xff && ip[11] == 0xff) ||
-		ip[0] == 0xfe && ip[1]&0xc0 == 0xc0 || // !(IPv6 site-local unicast)
-		ip.IsLinkLocalUnicast() ||
-		ip.IsLinkLocalMulticast() {
+		// IPv4-mapped IPv6 addresses cannot be connected to
+		(!ipv6Only && isZeros(ip[0:10]) && ip[10] == 0xff && ip[11] == 0xff) {
 		return false
 	}
 	return true

conn_test.go

@@ -388,14 +388,12 @@ func TestValidCommunicationIPv46Mixed(t *testing.T) {
 	bServer, err := Server(nil, ipv6.NewPacketConn(bSock6), &Config{})
 	check(err, t)
 
-	ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
-	defer cancel()
-
-	// we want ipv6 but all we can offer is an ipv4 address, so it should fail until we support
-	// allowing this explicitly via configuration on the aServer side
-	if _, _, err := bServer.Query(ctx, "pion-mdns-1.local"); !errors.Is(err, errContextElapsed) {
-		t.Fatalf("Query expired but returned unexpected error %v", err)
+	header, addr, err := bServer.Query(context.TODO(), "pion-mdns-1.local")
+	check(err, t)
+	if header.Type != dnsmessage.TypeAAAA {
+		t.Fatalf("expected AAAA but got %s", header.Type)
 	}
+	checkIPv6(addr, t)
 
 	check(aServer.Close(), t)
 	check(bServer.Close(), t)
@@ -434,7 +432,7 @@ func TestValidCommunicationIPv46MixedLocalAddress(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
 	defer cancel()
 
-	// we want ipv6 but all we can offer is an ipv4 address, so it should fail until we support
+	// we want ipv6 but all we can offer is an ipv4 mapped address, so it should fail until we support
 	// allowing this explicitly via configuration on the aServer side
 	if _, _, err := bServer.Query(ctx, "pion-mdns-1.local"); !errors.Is(err, errContextElapsed) {
 		t.Fatalf("Query expired but returned unexpected error %v", err)
@@ -474,9 +472,6 @@ func TestValidCommunicationIPv66MixedLocalAddress(t *testing.T) {
 	bServer, err := Server(nil, ipv6.NewPacketConn(bSock6), &Config{})
 	check(err, t)
 
-	// this will work compared to TestValidCommunicationIPv46MixedLocalAddress
-	// since this is considered to be an IPv6 only application so IPv4-mapped IPv6 addresses
-	// are allowed
 	header, addr, err := bServer.Query(context.TODO(), "pion-mdns-1.local")
 	check(err, t)
 	if header.Type != dnsmessage.TypeAAAA {