+ /* RFC 6582 Sec. 3.2
+ * Deflate the congestion window by the amount of new data
+ * acknowledged by the Cumulative Acknowledgment field.
+ * If the partial ACK acknowledges at least one SMSS of new data,
+ * then add back SMSS bytes to the congestion window. This
+ * artificially inflates the congestion window in order to reflect
+ * the additional segment that has left the network. This "partial
+ * window deflation" attempts to ensure that, when fast recovery
+ * eventually ends, approximately ssthresh amount of data will be
+ * outstanding in the network. */
+ tc->cwnd = (tc->cwnd > tc->bytes_acked + tc->snd_mss) ?
+ tc->cwnd - tc->bytes_acked :
+ tc->snd_mss;