tcp: send unsent data in fast recovery

Allows sending of unsent data in fast recovery and consolidates logic in
tcp, instead of splitting it between tcp fast retransmit and tcp output
path called by the session layer.

Change-Id: I9b12cdf2aa2ac50b9f25e46856fed037163501fe
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 19 insertions, 32 deletions

diff --git a/src/vnet/tcp/tcp.c b/src/vnet/tcp/tcp.c
index 1fb95b3ad3a..f8e74a88fcf 100644
--- a/src/vnet/tcp/tcp.c
+++ b/src/vnet/tcp/tcp.c
@@ -972,13 +972,13 @@ format_tcp_scoreboard (u8 * s, va_list * args)
 
   hole = scoreboard_first_hole (sb);
   if (hole)
-    s = format (s, "\n%Uhead %u tail %u %u holes:\n", format_white_space,
-		indent, sb->head, sb->tail, pool_elts (sb->holes));
+    s = format (s, "\n%Uhead %u tail %u %u holes:\n%U", format_white_space,
+		indent, sb->head, sb->tail, pool_elts (sb->holes),
+		format_white_space, indent);
 
   while (hole)
     {
-      s = format (s, "%U%U", format_white_space, indent, format_tcp_sack_hole,
-		  hole, tc);
+      s = format (s, "%U", format_tcp_sack_hole, hole, tc);
       hole = scoreboard_next_hole (sb, hole);
     }
 
@@ -1051,38 +1051,25 @@ tcp_snd_space_inline (tcp_connection_t * tc)
 {
   int snd_space, snt_limited;
 
-  if (PREDICT_TRUE (!tcp_in_fastrecovery (tc)))
-    {
-      snd_space = tcp_available_output_snd_space (tc);
-
-      /* If we haven't gotten dupacks or if we did and have gotten sacked
-       * bytes then we can still send as per Limited Transmit (RFC3042) */
-      if (PREDICT_FALSE (tc->rcv_dupacks != 0
-			 && (tcp_opts_sack_permitted (tc)
-			     && tc->sack_sb.last_sacked_bytes == 0)))
-	{
-	  if (tc->rcv_dupacks == 1 && tc->limited_transmit != tc->snd_nxt)
-	    tc->limited_transmit = tc->snd_nxt;
-	  ASSERT (seq_leq (tc->limited_transmit, tc->snd_nxt));
+  if (PREDICT_FALSE (tcp_in_fastrecovery (tc)))
+    return 0;
 
-	  snt_limited = tc->snd_nxt - tc->limited_transmit;
-	  snd_space = clib_max (2 * tc->snd_mss - snt_limited, 0);
-	}
-      return tcp_round_snd_space (tc, snd_space);
-    }
+  snd_space = tcp_available_output_snd_space (tc);
 
-  /* RFC 5681: When previously unsent data is available and the new value of
-   * cwnd and the receiver's advertised window allow, a TCP SHOULD send 1*SMSS
-   * bytes of previously unsent data. */
-  if (tcp_in_fastrecovery (tc) && !tcp_fastrecovery_sent_1_smss (tc))
+  /* If we haven't gotten dupacks or if we did and have gotten sacked
+   * bytes then we can still send as per Limited Transmit (RFC3042) */
+  if (PREDICT_FALSE (tc->rcv_dupacks != 0
+		     && (tcp_opts_sack_permitted (tc)
+			 && tc->sack_sb.last_sacked_bytes == 0)))
     {
-      if (tcp_available_cc_snd_space (tc) < tc->snd_mss)
-	return 0;
-      tcp_fastrecovery_1_smss_on (tc);
-      return tc->snd_mss;
-    }
+      if (tc->rcv_dupacks == 1 && tc->limited_transmit != tc->snd_nxt)
+	tc->limited_transmit = tc->snd_nxt;
+      ASSERT (seq_leq (tc->limited_transmit, tc->snd_nxt));
 
-  return 0;
+      snt_limited = tc->snd_nxt - tc->limited_transmit;
+      snd_space = clib_max (2 * tc->snd_mss - snt_limited, 0);
+    }
+  return tcp_round_snd_space (tc, snd_space);
 }
 
 u32