proto for destination

proxy/dokodemo/sockopt_linux.go

@@ -16,18 +16,18 @@ func GetOriginalDestination(conn internet.Connection) v2net.Destination {
 	tcpConn, ok := conn.(internet.SysFd)
 	if !ok {
 		log.Info("Dokodemo: Failed to get sys fd.")
-		return nil
+		return v2net.Destination{}
 	}
 	fd, err := tcpConn.SysFd()
 	if err != nil {
 		log.Info("Dokodemo: Failed to get original destination: ", err)
-		return nil
+		return v2net.Destination{}
 	}
 
 	addr, err := syscall.GetsockoptIPv6Mreq(fd, syscall.IPPROTO_IP, SO_ORIGINAL_DST)
 	if err != nil {
 		log.Info("Dokodemo: Failed to call getsockopt: ", err)
-		return nil
+		return v2net.Destination{}
 	}
 	ip := v2net.IPAddress(addr.Multiaddr[4:8])
 	port := uint16(addr.Multiaddr[2])<<8 + uint16(addr.Multiaddr[3])