Fixes and improved tcp/session debugging

- Fix rx sack option parsing
- Add session sack scoreboard tracing and replaying
- Add svm fifo tracing and replaying
- Scoreboard/svm fifo ooo segment reception fixes
- Improved overall debugging

Change-Id: Ieae07eba355e66f5935253232bb00f2dfb7ece00
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 79 insertions, 35 deletions

diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 45db0da69c6..bc7d9015789 100644
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -206,8 +206,8 @@ tcp_options_parse (tcp_header_t * th, tcp_options_t * to)
 	  vec_reset_length (to->sacks);
 	  for (j = 0; j < to->n_sack_blocks; j++)
 	    {
-	      b.start = clib_net_to_host_u32 (*(u32 *) (data + 2 + 4 * j));
-	      b.end = clib_net_to_host_u32 (*(u32 *) (data + 6 + 4 * j));
+	      b.start = clib_net_to_host_u32 (*(u32 *) (data + 2 + 8 * j));
+	      b.end = clib_net_to_host_u32 (*(u32 *) (data + 6 + 8 * j));
 	      vec_add1 (to->sacks, b);
 	    }
 	  break;
@@ -540,6 +540,10 @@ scoreboard_remove_hole (sack_scoreboard_t * sb, sack_scoreboard_hole_t * hole)
   if (scoreboard_hole_index (sb, hole) == sb->cur_rxt_hole)
     sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX;
 
+  /* Poison the entry */
+  if (CLIB_DEBUG > 0)
+    memset (hole, 0xfe, sizeof (*hole));
+
   pool_put (sb->holes, hole);
 }
 
@@ -555,7 +559,7 @@ scoreboard_insert_hole (sack_scoreboard_t * sb, u32 prev_index,
 
   hole->start = start;
   hole->end = end;
-  hole_index = hole - sb->holes;
+  hole_index = scoreboard_hole_index (sb, hole);
 
   prev = scoreboard_get_hole (sb, prev_index);
   if (prev)
@@ -680,12 +684,30 @@ scoreboard_next_rxt_hole (sack_scoreboard_t * sb,
 }
 
 void
-scoreboard_init_high_rxt (sack_scoreboard_t * sb)
+scoreboard_init_high_rxt (sack_scoreboard_t * sb, u32 seq)
 {
   sack_scoreboard_hole_t *hole;
   hole = scoreboard_first_hole (sb);
-  sb->high_rxt = hole->start;
-  sb->cur_rxt_hole = sb->head;
+  if (hole)
+    {
+      seq = seq_gt (seq, hole->start) ? seq : hole->start;
+      sb->cur_rxt_hole = sb->head;
+    }
+  sb->high_rxt = seq;
+}
+
+/**
+ * Test that scoreboard is sane after recovery
+ *
+ * Returns 1 if scoreboard is empty or if first hole beyond
+ * snd_una.
+ */
+u8
+tcp_scoreboard_is_sane_post_recovery (tcp_connection_t * tc)
+{
+  sack_scoreboard_hole_t *hole;
+  hole = scoreboard_first_hole (&tc->sack_sb);
+  return (!hole || seq_geq (hole->start, tc->snd_una));
 }
 
 void
@@ -712,7 +734,7 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
     {
       if (seq_lt (blk->start, blk->end)
 	  && seq_gt (blk->start, tc->snd_una)
-	  && seq_gt (blk->start, ack) && seq_leq (blk->end, tc->snd_nxt))
+	  && seq_gt (blk->start, ack) && seq_leq (blk->end, tc->snd_una_max))
 	{
 	  blk++;
 	  continue;
@@ -731,6 +753,8 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
   if (vec_len (tc->rcv_opts.sacks) == 0)
     return;
 
+  tcp_scoreboard_trace_add (tc, ack);
+
   /* Make sure blocks are ordered */
   for (i = 0; i < vec_len (tc->rcv_opts.sacks); i++)
     for (j = i + 1; j < vec_len (tc->rcv_opts.sacks); j++)
@@ -797,7 +821,7 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
 		      sb->last_bytes_delivered +=
 			next_hole->start - hole->end;
 		    }
-		  else if (!next_hole)
+		  else
 		    {
 		      ASSERT (seq_geq (sb->high_sacked, ack));
 		      sb->snd_una_adv = sb->high_sacked - ack;
@@ -824,12 +848,14 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
 	  if (seq_lt (blk->end, hole->end))
 	    {
 	      hole_index = scoreboard_hole_index (sb, hole);
-	      scoreboard_insert_hole (sb, hole_index, blk->end, hole->end);
+	      next_hole = scoreboard_insert_hole (sb, hole_index, blk->end,
+						  hole->end);
 
 	      /* Pool might've moved */
 	      hole = scoreboard_get_hole (sb, hole_index);
 	      hole->end = blk->start;
 	      blk_index++;
+	      ASSERT (hole->next == scoreboard_hole_index (sb, next_hole));
 	    }
 	  else if (seq_lt (blk->start, hole->end))
 	    {
@@ -957,7 +983,7 @@ tcp_cc_recover (tcp_connection_t * tc)
 
   ASSERT (tc->rto_boff == 0);
   ASSERT (!tcp_in_cong_recovery (tc));
-
+  ASSERT (tcp_scoreboard_is_sane_post_recovery (tc));
   TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 3);
   return 0;
 }
@@ -965,7 +991,7 @@ tcp_cc_recover (tcp_connection_t * tc)
 static void
 tcp_cc_update (tcp_connection_t * tc, vlib_buffer_t * b)
 {
-  ASSERT (!tcp_in_cong_recovery (tc));
+  ASSERT (!tcp_in_cong_recovery (tc) || tcp_is_lost_fin (tc));
 
   /* Congestion avoidance */
   tc->cc_algo->rcv_ack (tc);
@@ -1064,10 +1090,10 @@ tcp_cc_handle_event (tcp_connection_t * tc, u32 is_dack)
 	  ASSERT (tc->cwnd >= tc->snd_mss);
 
 	  /* If cwnd allows, send more data */
-	  if (tcp_opts_sack_permitted (&tc->rcv_opts)
-	      && scoreboard_first_hole (&tc->sack_sb))
+	  if (tcp_opts_sack_permitted (&tc->rcv_opts))
 	    {
-	      scoreboard_init_high_rxt (&tc->sack_sb);
+	      scoreboard_init_high_rxt (&tc->sack_sb,
+					tc->snd_una + tc->snd_mss);
 	      tcp_fast_retransmit_sack (tc);
 	    }
 	  else
@@ -1134,12 +1160,13 @@ partial_ack:
   /* Remove retransmitted bytes that have been delivered */
   ASSERT (tc->bytes_acked + tc->sack_sb.snd_una_adv
 	  >= tc->sack_sb.last_bytes_delivered);
-  rxt_delivered = tc->bytes_acked + tc->sack_sb.snd_una_adv
-    - tc->sack_sb.last_bytes_delivered;
-  if (0 && rxt_delivered && seq_gt (tc->sack_sb.high_rxt, tc->snd_una))
+
+  if (seq_lt (tc->snd_una, tc->sack_sb.high_rxt))
     {
       /* If we have sacks and we haven't gotten an ack beyond high_rxt,
        * remove sacked bytes delivered */
+      rxt_delivered = tc->bytes_acked + tc->sack_sb.snd_una_adv
+	- tc->sack_sb.last_bytes_delivered;
       ASSERT (tc->snd_rxt_bytes >= rxt_delivered);
       tc->snd_rxt_bytes -= rxt_delivered;
     }
@@ -1256,6 +1283,18 @@ tcp_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b,
   return 0;
 }
 
+static u8
+tcp_sack_vector_is_sane (sack_block_t * sacks)
+{
+  int i;
+  for (i = 1; i < vec_len (sacks); i++)
+    {
+      if (sacks[i - 1].end == sacks[i].start)
+	return 0;
+    }
+  return 1;
+}
+
 /**
  * Build SACK list as per RFC2018.
  *
@@ -1316,6 +1355,9 @@ tcp_update_sack_list (tcp_connection_t * tc, u32 start, u32 end)
   /* Replace old vector with new one */
   vec_free (tc->snd_sacks);
   tc->snd_sacks = new_list;
+
+  /* Segments should not 'touch' */
+  ASSERT (tcp_sack_vector_is_sane (tc->snd_sacks));
 }
 
 /** Enqueue data for delivery to application */
@@ -1330,7 +1372,6 @@ tcp_session_enqueue_data (tcp_connection_t * tc, vlib_buffer_t * b,
   /* Pure ACK. Update rcv_nxt and be done. */
   if (PREDICT_FALSE (data_len == 0))
     {
-      tc->rcv_nxt = vnet_buffer (b)->tcp.seq_end;
       return TCP_ERROR_PURE_ACK;
     }
 
@@ -1385,7 +1426,7 @@ tcp_session_enqueue_ooo (tcp_connection_t * tc, vlib_buffer_t * b,
 			 u16 data_len)
 {
   stream_session_t *s0;
-  int rv;
+  int rv, offset;
 
   ASSERT (seq_gt (vnet_buffer (b)->tcp.seq_number, tc->rcv_nxt));
 
@@ -1421,12 +1462,12 @@ tcp_session_enqueue_ooo (tcp_connection_t * tc, vlib_buffer_t * b,
       newest = svm_fifo_newest_ooo_segment (s0->server_rx_fifo);
       if (newest)
 	{
-	  start =
-	    tc->rcv_nxt + ooo_segment_offset (s0->server_rx_fifo, newest);
+	  offset = ooo_segment_offset (s0->server_rx_fifo, newest);
+	  ASSERT (offset <= vnet_buffer (b)->tcp.seq_number - tc->rcv_nxt);
+	  start = tc->rcv_nxt + offset;
 	  end = start + ooo_segment_length (s0->server_rx_fifo, newest);
 	  tcp_update_sack_list (tc, start, end);
-
-	  ASSERT (seq_gt (start, tc->rcv_nxt));
+	  svm_fifo_newest_ooo_segment_reset (s0->server_rx_fifo);
 	}
     }
 
@@ -2736,12 +2777,12 @@ tcp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 	      /* lookup session */
 	      tc0 =
 		(tcp_connection_t *)
-		stream_session_lookup_transport4 (&ip40->dst_address,
-						  &ip40->src_address,
-						  tcp0->dst_port,
-						  tcp0->src_port,
-						  SESSION_TYPE_IP4_TCP,
-						  my_thread_index);
+		stream_session_lookup_transport_wt4 (&ip40->dst_address,
+						     &ip40->src_address,
+						     tcp0->dst_port,
+						     tcp0->src_port,
+						     SESSION_TYPE_IP4_TCP,
+						     my_thread_index);
 	    }
 	  else
 	    {
@@ -2754,12 +2795,12 @@ tcp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 
 	      tc0 =
 		(tcp_connection_t *)
-		stream_session_lookup_transport6 (&ip60->src_address,
-						  &ip60->dst_address,
-						  tcp0->src_port,
-						  tcp0->dst_port,
-						  SESSION_TYPE_IP6_TCP,
-						  my_thread_index);
+		stream_session_lookup_transport_wt6 (&ip60->src_address,
+						     &ip60->dst_address,
+						     tcp0->src_port,
+						     tcp0->dst_port,
+						     SESSION_TYPE_IP6_TCP,
+						     my_thread_index);
 	    }
 
 	  /* Length check */
@@ -2931,6 +2972,8 @@ do {                                                       	\
   _(ESTABLISHED, TCP_FLAG_RST | TCP_FLAG_ACK, TCP_INPUT_NEXT_ESTABLISHED,
     TCP_ERROR_NONE);
   _(ESTABLISHED, TCP_FLAG_SYN, TCP_INPUT_NEXT_ESTABLISHED, TCP_ERROR_NONE);
+  _(ESTABLISHED, TCP_FLAG_SYN | TCP_FLAG_ACK, TCP_INPUT_NEXT_ESTABLISHED,
+    TCP_ERROR_NONE);
   /* ACK or FIN-ACK to our FIN */
   _(FIN_WAIT_1, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
   _(FIN_WAIT_1, TCP_FLAG_ACK | TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS,
@@ -2954,6 +2997,7 @@ do {                                                       	\
   _(TIME_WAIT, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
   _(TIME_WAIT, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
     TCP_ERROR_NONE);
+  _(TIME_WAIT, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
   _(CLOSED, TCP_FLAG_ACK, TCP_INPUT_NEXT_RESET, TCP_ERROR_CONNECTION_CLOSED);
   _(CLOSED, TCP_FLAG_RST, TCP_INPUT_NEXT_DROP, TCP_ERROR_CONNECTION_CLOSED);
   _(CLOSED, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RESET,