From: Florin Coras <fcoras@cisco.com>
Date: Tue, 26 Sep 2017 16:30:40 +0000 (-0400)
Subject: tcp: update snd_nxt after congestion recovery
X-Git-Tag: v17.10-rc1~11
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=84275e96559ced02d456cb8b034237d5782b9693;p=vpp.git

tcp: update snd_nxt after congestion recovery

Change-Id: I2cf4c4850b9c3c093a7dce0cec89b9f710f69393
Signed-off-by: Florin Coras <fcoras@cisco.com>
---

diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 0a36d063482..62dcdc5e711 100644
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -937,6 +937,7 @@ tcp_cc_recovery_exit (tcp_connection_t * tc)
   tc->rto_boff = 0;
   tcp_update_rto (tc);
   tc->snd_rxt_ts = 0;
+  tc->snd_nxt = tc->snd_una_max;
   tcp_recovery_off (tc);
   TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 3);
 }
@@ -947,6 +948,7 @@ tcp_cc_fastrecovery_exit (tcp_connection_t * tc)
   tc->cc_algo->recovered (tc);
   tc->snd_rxt_bytes = 0;
   tc->rcv_dupacks = 0;
+  tc->snd_nxt = tc->snd_una_max;
   tcp_fastrecovery_off (tc);
   tcp_fastrecovery_1_smss_off (tc);
   TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 3);
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index cb1fcc9ab49..a954bfa7b4e 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -1391,13 +1391,12 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
       /* Increment RTO backoff (also equal to number of retries) and go back
        * to first un-acked byte  */
       tc->rto_boff += 1;
-      tc->snd_nxt = tc->snd_una;
 
       /* First retransmit timeout */
       if (tc->rto_boff == 1)
 	tcp_rtx_timeout_cc (tc);
 
-      /* Exponential backoff */
+      tc->snd_nxt = tc->snd_una;
       tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
 
       TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
@@ -1515,7 +1514,7 @@ tcp_timer_persist_handler (u32 index)
   u32 thread_index = vlib_get_thread_index ();
   tcp_connection_t *tc;
   vlib_buffer_t *b;
-  u32 bi, old_snd_nxt, max_snd_bytes, available_bytes, offset;
+  u32 bi, max_snd_bytes, available_bytes, offset;
   int n_bytes = 0;
   u8 *data;
 
@@ -1567,14 +1566,11 @@ tcp_timer_persist_handler (u32 index)
   n_bytes = stream_session_peek_bytes (&tc->connection, data, offset,
 				       max_snd_bytes);
   b->current_length = n_bytes;
-  ASSERT (n_bytes != 0 && (tc->snd_nxt == tc->snd_una_max || tc->rto_boff > 1
-			   || tcp_timer_is_active (tc,
-						   TCP_TIMER_RETRANSMIT)));
+  ASSERT (n_bytes != 0 && (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)
+			   || tc->snd_nxt == tc->snd_una_max
+			   || tc->rto_boff > 1));
 
-  /* Allow updating of snd_una_max but don't update snd_nxt */
-  old_snd_nxt = tc->snd_nxt;
   tcp_push_hdr_i (tc, b, tc->state, 0);
-  tc->snd_nxt = old_snd_nxt;
   tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
 
   /* Just sent new data, enable retransmit */