+ /* If we have outstanding data and this is within the window, accept it,
+ * probably retransmit has timed out. Otherwise ACK segment and then
+ * drop it */
+ if (seq_gt (vnet_buffer (b)->tcp.ack_number, tc->snd_una_max))
+ {
+ tcp_make_ack (tc, b);
+ *next = tcp_next_output (tc->c_is_ip4);
+ *error = TCP_ERROR_ACK_INVALID;
+ TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 0,
+ vnet_buffer (b)->tcp.ack_number);
+ return -1;
+ }
+
+ TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 2,
+ vnet_buffer (b)->tcp.ack_number);
+
+ tc->snd_nxt = vnet_buffer (b)->tcp.ack_number;
+ *error = TCP_ERROR_ACK_FUTURE;