+
+#ifdef IPV6_V6ONLY
+#ifdef IPPROTO_IPV6
+ const int on = 1;
+ if (desc->af == AF_INET6)
+ if (0 != setsockopt (desc->fd, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof (on)))
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_DEBUG, "setsockopt");
+#if 0
+ /* is this needed or desired? or done elsewhere? */
+ if (0 != setsockopt (desc->fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof (on)))
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_DEBUG, "setsockopt");
+#endif
+#endif
+#endif