tcp: send unsent data in fast recovery

[vpp.git] / src / vnet / tcp / tcp_input.c

diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 21e5f3c..0b79a66 100644 (file)
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -719,8 +719,7 @@ scoreboard_update_bytes (tcp_connection_t * tc, sack_scoreboard_t * sb)
 sack_scoreboard_hole_t *
 scoreboard_next_rxt_hole (sack_scoreboard_t * sb,
                          sack_scoreboard_hole_t * start,
-                         u8 have_sent_1_smss,
-                         u8 * can_rescue, u8 * snd_limited)
+                         u8 have_unsent, u8 * can_rescue, u8 * snd_limited)
 {
   sack_scoreboard_hole_t *hole = 0;
 
@@ -742,11 +741,11 @@ scoreboard_next_rxt_hole (sack_scoreboard_t * sb,
     }
   else
     {
-      /* Rule (2): output takes care of transmitting new data */
-      if (!have_sent_1_smss)
+      /* Rule (2): available unsent data */
+      if (have_unsent)
        {
-         hole = 0;
          sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX;
+         return 0;
        }
       /* Rule (3): if hole not lost */
       else if (seq_lt (hole->start, sb->high_sacked))
@@ -772,16 +771,17 @@ scoreboard_next_rxt_hole (sack_scoreboard_t * sb,
 }
 
 static void
-scoreboard_init_high_rxt (sack_scoreboard_t * sb, u32 seq)
+scoreboard_init_high_rxt (sack_scoreboard_t * sb, u32 snd_una)
 {
   sack_scoreboard_hole_t *hole;
   hole = scoreboard_first_hole (sb);
   if (hole)
     {
-      seq = seq_gt (seq, hole->start) ? seq : hole->start;
+      snd_una = seq_gt (snd_una, hole->start) ? snd_una : hole->start;
       sb->cur_rxt_hole = sb->head;
     }
-  sb->high_rxt = seq;
+  sb->high_rxt = snd_una;
+  sb->rescue_rxt = snd_una - 1;
 }
 
 void
@@ -1306,7 +1306,6 @@ tcp_cc_handle_event (tcp_connection_t * tc, u32 is_dack)
            {
              tc->cwnd = tc->ssthresh;
              scoreboard_init_high_rxt (&tc->sack_sb, tc->snd_una);
-             tc->sack_sb.rescue_rxt = tc->snd_una - 1;
            }
          else
            {
@@ -1316,6 +1315,7 @@ tcp_cc_handle_event (tcp_connection_t * tc, u32 is_dack)
              tc->cwnd = tc->ssthresh + 3 * tc->snd_mss;
            }
 
+         /* Constrain rate until we get a partial ack */
          pacer_wnd = clib_max (0.1 * tc->cwnd, 2 * tc->snd_mss);
          tcp_connection_tx_pacer_reset (tc, pacer_wnd,
                                         0 /* start bucket */ );
@@ -1387,6 +1387,10 @@ partial_ack:
    * Legitimate ACK. 2) If PARTIAL ACK try to retransmit
    */
 
+  /* Update the pacing rate. For the first partial ack we move from
+   * the artificially constrained rate to the one after congestion */
+  tcp_connection_tx_pacer_update (tc);
+
   /* XXX limit this only to first partial ack? */
   tcp_retransmit_timer_force_update (tc);
 
@@ -1422,10 +1426,14 @@ partial_ack:
        {
          /* Apparently all retransmitted holes have been acked */
          tc->snd_rxt_bytes = 0;
+         tc->sack_sb.high_rxt = tc->snd_una;
        }
     }
   else
     {
+      tcp_fastrecovery_first_on (tc);
+      /* Reuse last bytes delivered to track total bytes acked */
+      tc->sack_sb.last_bytes_delivered += tc->bytes_acked;
       if (tc->snd_rxt_bytes > tc->bytes_acked)
        tc->snd_rxt_bytes -= tc->bytes_acked;
       else
@@ -1473,7 +1481,7 @@ tcp_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b,
        {
          tcp_make_ack (tc, b);
          *next = tcp_next_output (tc->c_is_ip4);
-         *error = TCP_ERROR_ACK_INVALID;
+         *error = TCP_ERROR_ACK_FUTURE;
          TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 0,
                       vnet_buffer (b)->tcp.ack_number);
          return -1;
@@ -1483,7 +1491,6 @@ tcp_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b,
                   vnet_buffer (b)->tcp.ack_number);
 
       tc->snd_nxt = vnet_buffer (b)->tcp.ack_number;
-      *error = TCP_ERROR_ACK_FUTURE;
     }
 
   /* If old ACK, probably it's an old dupack */