+
+ /* If we haven't gotten dupacks or if we did and have gotten sacked bytes
+ * then we can still send */
+ if (PREDICT_TRUE (tcp_in_fastrecovery (tc) == 0
+ && (tc->rcv_dupacks == 0
+ || tc->sack_sb.last_sacked_bytes)))
+ {
+ snd_space = tcp_available_snd_space (tc);
+
+ /* If we can't write at least a segment, don't try at all */
+ if (snd_space < tc->snd_mss)
+ return 0;
+
+ /* round down to mss multiple */
+ return snd_space - (snd_space % tc->snd_mss);
+ }
+
+ /* If in fast recovery, send 1 SMSS if wnd allows */
+ if (tcp_in_fastrecovery (tc) && tcp_available_snd_space (tc)
+ && tcp_fastrecovery_sent_1_smss (tc))
+ {
+ tcp_fastrecovery_1_smss_on (tc);
+ return tc->snd_mss;
+ }
+
+ return 0;