+ udp_init_session(sc);
+ mps = generic_max_transport_msg_size(sc->fd) - sizeof(struct udphdr);
+ PARA_INFO_LOG("current MPS = %d bytes\n", mps);
+ return mps;
+}
+
+/** Check and clear socket error if any. */
+static int udp_check_socket_state(struct udp_target *ut)
+{
+ int ret;
+ socklen_t errlen = sizeof(ret);
+
+ if (getsockopt(ut->sc->fd, SOL_SOCKET, SO_ERROR, &ret, &errlen) < 0) {
+ PARA_ERROR_LOG("SO_ERROR failed: %s\n", strerror(ret));
+ return 0;
+ } else if (ret == 0) {
+ return 0;
+ } else if (ret == ECONNREFUSED) {
+ time_t dist = now->tv_sec - ut->last_unreachable;
+
+ if (dist <= UDP_MAX_UNREACHABLE_TIME) {
+ return 0;
+ } else if (dist > 2 * UDP_MAX_UNREACHABLE_TIME) {
+ ut->last_unreachable = now->tv_sec;
+ return 0;
+ } else {
+ /*
+ * unreachable_time < dist <= 2 * unreachable_time
+ * No errors are allowed during this time window.
+ */
+ PARA_NOTICE_LOG("Evicting %s#%d after %d seconds "
+ "of connection errors.\n",
+ ut->host, ut->port, (int)dist);
+ }
+ }
+ return -ERRNO_TO_PARA_ERROR(ret);
+}
+
+static int udp_send_fec(struct sender_client *sc, char *buf, size_t len)
+{
+ struct udp_target *ut = sc->private_data;
+ int ret;
+
+ if (sender_status == SENDER_OFF)
+ return 0;
+ if (len == 0 && !cq_peek(ut->sc->cq))
+ return 0;
+ ret = udp_check_socket_state(ut);