1 files changed, 29 insertions, 0 deletions
diff --git a/src/pkg/syscall/route_darwin.go b/src/pkg/syscall/route_darwin.go
index 8f79b708d..9d3a701da 100644
--- a/src/pkg/syscall/route_darwin.go
+++ b/src/pkg/syscall/route_darwin.go
@@ -46,3 +46,32 @@ type InterfaceMulticastAddrMessage struct {
 	Header IfmaMsghdr2
 	Data   []byte
 }
+
+const rtaIfmaMask = RTA_GATEWAY | RTA_IFP | RTA_IFA
+
+func (m *InterfaceMulticastAddrMessage) sockaddr() (sas []Sockaddr) {
+	if m.Header.Addrs&rtaIfmaMask == 0 {
+		return nil
+	}
+
+	buf := m.Data[:]
+	for i := uint(0); i < RTAX_MAX; i++ {
+		if m.Header.Addrs&rtaIfmaMask&(1<<i) == 0 {
+			continue
+		}
+		rsa := (*RawSockaddr)(unsafe.Pointer(&buf[0]))
+		switch i {
+		case RTAX_IFA:
+			sa, e := anyToSockaddr((*RawSockaddrAny)(unsafe.Pointer(rsa)))
+			if e != 0 {
+				return nil
+			}
+			sas = append(sas, sa)
+		case RTAX_GATEWAY, RTAX_IFP:
+			// nothing to do
+		}
+		buf = buf[rsaAlignOf(int(rsa.Len)):]
+	}
+
+	return sas
+}