From 8b4114e52f69b9292efb282e49ed4d90699ceeb8 Mon Sep 17 00:00:00 2001
From: Florin Coras <fcoras@cisco.com>
Date: Tue, 3 Sep 2019 12:37:11 -0700
Subject: tcp: cc algos handle cwnd on congestion signal

Type: refactor

Change-Id: I15b10a22d0d0b83075a0eef5ef8c09cf76989866
Signed-off-by: Florin Coras <fcoras@cisco.com>
---
 src/vnet/tcp/tcp_cubic.c   |  4 ++++
 src/vnet/tcp/tcp_input.c   | 13 +------------
 src/vnet/tcp/tcp_newreno.c |  6 ++++++
 3 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/src/vnet/tcp/tcp_cubic.c b/src/vnet/tcp/tcp_cubic.c
index 0b4226d6f12..aa318961533 100644
--- a/src/vnet/tcp/tcp_cubic.c
+++ b/src/vnet/tcp/tcp_cubic.c
@@ -103,6 +103,10 @@ cubic_congestion (tcp_connection_t * tc)
 
   cd->w_max = w_max;
   tc->ssthresh = clib_max (tc->cwnd * beta_cubic, 2 * tc->snd_mss);
+
+  tc->cwnd = tc->ssthresh;
+  if (!tcp_opts_sack_permitted (&tc->rcv_opts))
+    tc->cwnd += 3 * tc->snd_mss;
 }
 
 static void
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 45a40a276b0..1a9eff51a72 100755
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -1367,20 +1367,9 @@ tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
 	    }
 
 	  tcp_cc_init_congestion (tc);
-	  tcp_cc_rcv_cong_ack (tc, TCP_CC_DUPACK, rs);
 
 	  if (tcp_opts_sack_permitted (&tc->rcv_opts))
-	    {
-	      tc->cwnd = tc->ssthresh;
-	      scoreboard_init_high_rxt (&tc->sack_sb, tc->snd_una);
-	    }
-	  else
-	    {
-	      /* Post retransmit update cwnd to ssthresh and account for the
-	       * three segments that have left the network and should've been
-	       * buffered at the receiver XXX */
-	      tc->cwnd = tc->ssthresh + 3 * tc->snd_mss;
-	    }
+	    scoreboard_init_high_rxt (&tc->sack_sb, tc->snd_una);
 
 	  /* Constrain rate until we get a partial ack */
 	  pacer_wnd = clib_max (0.1 * tc->cwnd, 2 * tc->snd_mss);
diff --git a/src/vnet/tcp/tcp_newreno.c b/src/vnet/tcp/tcp_newreno.c
index 7e37efb1052..8b704a6ba04 100644
--- a/src/vnet/tcp/tcp_newreno.c
+++ b/src/vnet/tcp/tcp_newreno.c
@@ -19,6 +19,12 @@ static void
 newreno_congestion (tcp_connection_t * tc)
 {
   tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
+  tc->cwnd = tc->ssthresh;
+  /* Post retransmit update cwnd to ssthresh and account for the
+   * three segments that have left the network and should've been
+   * buffered at the receiver XXX */
+  if (!tcp_opts_sack_permitted (&tc->rcv_opts))
+    tc->cwnd += 3 * tc->snd_mss;
 }
 
 static void
-- 
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