tcp: fix duplicate sack whith reneging

Type: fix

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I6f7fb91e059996ff702eb9c36e3abaed237fe221
(cherry picked from commit 067f8f963d64b1cbc70f2b78ebd2c6d3791e7d22)

2 files changed, 108 insertions, 17 deletions

diff --git a/src/plugins/unittest/tcp_test.c b/src/plugins/unittest/tcp_test.c
index c14a74c6ebb..25535e11ca6 100644
--- a/src/plugins/unittest/tcp_test.c
+++ b/src/plugins/unittest/tcp_test.c
@@ -85,6 +85,7 @@ tcp_test_sack_rx (vlib_main_t * vm, unformat_input_t * input)
 
   clib_memset (tc, 0, sizeof (*tc));
 
+  tc->flags |= TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY;
   tc->snd_una = 0;
   tc->snd_una_max = 1000;
   tc->snd_nxt = 1000;
@@ -132,11 +133,12 @@ tcp_test_sack_rx (vlib_main_t * vm, unformat_input_t * input)
   TCP_TEST ((sb->lost_bytes == 300), "lost bytes %u", sb->lost_bytes);
 
   /*
-   * Inject odd blocks
+   * Inject odd blocks except the last
+   *
    */
 
   vec_reset_length (tc->rcv_opts.sacks);
-  for (i = 0; i < 1000 / 200; i++)
+  for (i = 0; i < 800 / 200; i++)
     {
       vec_add1 (tc->rcv_opts.sacks, sacks[i * 2 + 1]);
     }
@@ -148,33 +150,120 @@ tcp_test_sack_rx (vlib_main_t * vm, unformat_input_t * input)
 		     sb, tc);
 
   hole = scoreboard_first_hole (sb);
-  TCP_TEST ((pool_elts (sb->holes) == 1),
+  TCP_TEST ((pool_elts (sb->holes) == 2),
 	    "scoreboard has %d holes", pool_elts (sb->holes));
   TCP_TEST ((hole->start == 0 && hole->end == 100),
 	    "first hole start %u end %u", hole->start, hole->end);
-  TCP_TEST ((sb->sacked_bytes == 900), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->sacked_bytes == 800), "sacked bytes %d", sb->sacked_bytes);
   TCP_TEST ((!sb->is_reneging), "is not reneging");
-  TCP_TEST ((sb->high_sacked == 1000), "high sacked %u", sb->high_sacked);
-  TCP_TEST ((sb->last_sacked_bytes == 500),
+  TCP_TEST ((sb->high_sacked == 900), "high sacked %u", sb->high_sacked);
+  TCP_TEST ((sb->last_sacked_bytes == 400),
 	    "last sacked bytes %d", sb->last_sacked_bytes);
   TCP_TEST ((sb->lost_bytes == 100), "lost bytes %u", sb->lost_bytes);
 
   /*
-   *  Ack until byte 100 - this is reneging because we should ack until 1000
+   *  Ack until byte 100 - this is reneging because we should ack until 900
    */
   tcp_rcv_sacks (tc, 100);
   if (verbose)
     vlib_cli_output (vm, "\nack until byte 100:\n%U", format_tcp_scoreboard,
 		     sb, tc);
 
-  TCP_TEST ((pool_elts (sb->holes) == 0), "scoreboard has %d elements",
+  TCP_TEST ((pool_elts (sb->holes) == 1), "scoreboard has %d elements",
 	    pool_elts (sb->holes));
   TCP_TEST ((sb->is_reneging), "is reneging");
 
   /*
-   * Sack all up to 1000
+   * Make sure we accept duplicate acks while reneging.
    */
   tc->snd_una = 100;
+  sb->high_rxt = 950;
+
+  block.start = 900;
+  block.end = 950;
+  vec_add1 (tc->rcv_opts.sacks, block);
+
+  tcp_rcv_sacks (tc, 100);
+  TCP_TEST ((pool_elts (sb->holes) == 1), "scoreboard has %d elements",
+	    pool_elts (sb->holes));
+  TCP_TEST ((sb->is_reneging), "is reneging");
+  TCP_TEST ((sb->last_sacked_bytes == 50), "last sacked bytes %d",
+	    sb->last_sacked_bytes);
+  TCP_TEST ((sb->rxt_sacked == 50), "last rxt sacked bytes %d",
+	    sb->rxt_sacked);
+
+  /*
+   * Sack all up to 950
+   */
+  tcp_rcv_sacks (tc, 950);
+  TCP_TEST ((sb->high_sacked == 950), "max sacked byte %u", sb->high_sacked);
+  TCP_TEST ((sb->sacked_bytes == 0), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->last_sacked_bytes == 0),
+	    "last sacked bytes %d", sb->last_sacked_bytes);
+  TCP_TEST ((sb->lost_bytes == 0), "lost bytes %u", sb->lost_bytes);
+  TCP_TEST ((!sb->is_reneging), "is not reneging");
+
+  /*
+   * Sack [960 970] [980 990]
+   */
+  sb->high_rxt = 985;
+
+  tc->snd_una = 950;
+  vec_reset_length (tc->rcv_opts.sacks);
+  block.start = 960;
+  block.end = 970;
+  vec_add1 (tc->rcv_opts.sacks, block);
+
+  block.start = 980;
+  block.end = 990;
+  vec_add1 (tc->rcv_opts.sacks, block);
+
+  tcp_rcv_sacks (tc, 950);
+  TCP_TEST ((sb->high_sacked == 990), "max sacked byte %u", sb->high_sacked);
+  TCP_TEST ((sb->sacked_bytes == 20), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->last_sacked_bytes == 20),
+	    "last sacked bytes %d", sb->last_sacked_bytes);
+  TCP_TEST ((sb->lost_bytes == 0), "lost bytes %u", sb->lost_bytes);
+  TCP_TEST ((!sb->is_reneging), "is not reneging");
+  TCP_TEST ((sb->rxt_sacked == 15), "last rxt sacked bytes %d",
+	    sb->rxt_sacked);
+
+  /*
+   * Ack up to 960 (reneging) + [961 971]
+   */
+  tc->rcv_opts.sacks[0].start = 961;
+  tc->rcv_opts.sacks[0].end = 971;
+
+  tcp_rcv_sacks (tc, 960);
+
+  TCP_TEST ((sb->is_reneging), "is reneging");
+  TCP_TEST ((sb->sacked_bytes == 21), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->last_sacked_bytes == 1),
+	    "last sacked bytes %d", sb->last_sacked_bytes);
+  TCP_TEST ((sb->rxt_sacked == 11), "last rxt sacked bytes %d",
+	    sb->rxt_sacked);
+  TCP_TEST ((sb->last_bytes_delivered == 0), "last bytes delivered %d",
+	    sb->last_bytes_delivered);
+
+  /*
+   * Ack up to 960 (reneging) + [961 990]
+   */
+  tc->snd_una = 960;
+  tc->rcv_opts.sacks[0].start = 961;
+  tc->rcv_opts.sacks[0].end = 990;
+
+  tcp_rcv_sacks (tc, 960);
+
+  TCP_TEST ((sb->is_reneging), "is reneging");
+  TCP_TEST ((sb->sacked_bytes == 30), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->last_sacked_bytes == 9),
+	    "last sacked bytes %d", sb->last_sacked_bytes);
+  TCP_TEST ((sb->rxt_sacked == 9), "last rxt sacked bytes %d",
+	    sb->rxt_sacked);
+
+  /*
+   * Sack all up to 1000
+   */
   tcp_rcv_sacks (tc, 1000);
   TCP_TEST ((sb->high_sacked == 1000), "max sacked byte %u", sb->high_sacked);
   TCP_TEST ((sb->sacked_bytes == 0), "sacked bytes %d", sb->sacked_bytes);
@@ -183,11 +272,10 @@ tcp_test_sack_rx (vlib_main_t * vm, unformat_input_t * input)
   TCP_TEST ((sb->lost_bytes == 0), "lost bytes %u", sb->lost_bytes);
   TCP_TEST ((!sb->is_reneging), "is not reneging");
 
-
   /*
    * Add new block
    */
-
+  tc->flags = 0;
   vec_reset_length (tc->rcv_opts.sacks);
 
   block.start = 1200;
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index e33a03271cd..92144f32504 100755
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -1119,7 +1119,11 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
   hole = pool_elt_at_index (sb->holes, sb->head);
 
   if (PREDICT_FALSE (sb->is_reneging))
-    sb->last_bytes_delivered += hole->start - tc->snd_una;
+    {
+      sb->last_bytes_delivered += clib_min (hole->start - tc->snd_una,
+					    ack - tc->snd_una);
+      sb->is_reneging = seq_lt (ack, hole->start);
+    }
 
   while (hole && blk_index < vec_len (rcv_sacks))
     {
@@ -1202,7 +1206,7 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
 	  || sb->is_reneging || sb->holes[sb->head].start == ack);
   ASSERT (sb->last_lost_bytes <= sb->lost_bytes);
   ASSERT ((ack - tc->snd_una) + sb->last_sacked_bytes
-	  - sb->last_bytes_delivered >= sb->rxt_sacked);
+	  - sb->last_bytes_delivered >= sb->rxt_sacked || sb->is_reneging);
   ASSERT ((ack - tc->snd_una) >= tc->sack_sb.last_bytes_delivered
 	  || (tc->flags & TCP_CONN_FINSNT));
 
@@ -1532,14 +1536,13 @@ tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
 }
 
 static void
-tcp_handle_old_ack (tcp_connection_t * tc, vlib_buffer_t * b,
-		    tcp_rate_sample_t * rs)
+tcp_handle_old_ack (tcp_connection_t * tc, tcp_rate_sample_t * rs)
 {
   if (!tcp_in_cong_recovery (tc))
     return;
 
   if (tcp_opts_sack_permitted (&tc->rcv_opts))
-    tcp_rcv_sacks (tc, vnet_buffer (b)->tcp.ack_number);
+    tcp_rcv_sacks (tc, tc->snd_una);
 
   tc->bytes_acked = 0;
 
@@ -1618,7 +1621,7 @@ tcp_rcv_ack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc, vlib_buffer_t * b,
       if (seq_lt (vnet_buffer (b)->tcp.ack_number, tc->snd_una - tc->rcv_wnd))
 	return -1;
 
-      tcp_handle_old_ack (tc, b, &rs);
+      tcp_handle_old_ack (tc, &rs);
 
       /* Don't drop yet */
       return 0;