1 files changed, 18 insertions, 19 deletions

diff --git a/src/net/interface_darwin.go b/src/net/interface_darwin.go
index ad0937db04..475b8611ce 100644
--- a/src/net/interface_darwin.go
+++ b/src/net/interface_darwin.go
@@ -29,35 +29,34 @@ func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
 				if err != nil {
 					return nil, err
 				}
-				ifmat = append(ifmat, ifma...)
+				if ifma != nil {
+					ifmat = append(ifmat, ifma)
+				}
 			}
 		}
 	}
 	return ifmat, nil
 }
 
-func newMulticastAddr(ifi *Interface, m *syscall.InterfaceMulticastAddrMessage) ([]Addr, error) {
+func newMulticastAddr(ifi *Interface, m *syscall.InterfaceMulticastAddrMessage) (*IPAddr, error) {
 	sas, err := syscall.ParseRoutingSockaddr(m)
 	if err != nil {
 		return nil, os.NewSyscallError("route sockaddr", err)
 	}
-	var ifmat []Addr
-	for _, sa := range sas {
-		switch sa := sa.(type) {
-		case *syscall.SockaddrInet4:
-			ifma := &IPAddr{IP: IPv4(sa.Addr[0], sa.Addr[1], sa.Addr[2], sa.Addr[3])}
-			ifmat = append(ifmat, ifma.toAddr())
-		case *syscall.SockaddrInet6:
-			ifma := &IPAddr{IP: make(IP, IPv6len)}
-			copy(ifma.IP, sa.Addr[:])
-			// NOTE: KAME based IPv6 protocol stack usually embeds
-			// the interface index in the interface-local or link-
-			// local address as the kernel-internal form.
-			if ifma.IP.IsInterfaceLocalMulticast() || ifma.IP.IsLinkLocalMulticast() {
-				ifma.IP[2], ifma.IP[3] = 0, 0
-			}
-			ifmat = append(ifmat, ifma.toAddr())
+	switch sa := sas[syscall.RTAX_IFA].(type) {
+	case *syscall.SockaddrInet4:
+		return &IPAddr{IP: IPv4(sa.Addr[0], sa.Addr[1], sa.Addr[2], sa.Addr[3])}, nil
+	case *syscall.SockaddrInet6:
+		ifma := IPAddr{IP: make(IP, IPv6len)}
+		copy(ifma.IP, sa.Addr[:])
+		// NOTE: KAME based IPv6 protcol stack usually embeds
+		// the interface index in the interface-local or
+		// link-local address as the kernel-internal form.
+		if ifma.IP.IsInterfaceLocalMulticast() || ifma.IP.IsLinkLocalMulticast() {
+			ifma.IP[2], ifma.IP[3] = 0, 0
 		}
+		return &ifma, nil
+	default:
+		return nil, nil
 	}
-	return ifmat, nil
 }