Add support for tcp/session buffer chains

Change-Id: I01c6e3dc3a1b2785df37bb66b19c4b5cbb8f3211
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 120 insertions, 52 deletions

diff --git a/src/vnet/session/node.c b/src/vnet/session/node.c
index 2d12ee2bac9..ce7c38683f5 100644
--- a/src/vnet/session/node.c
+++ b/src/vnet/session/node.c
@@ -70,6 +70,58 @@ static u32 session_type_to_next[] = {
   SESSION_QUEUE_NEXT_IP6_LOOKUP,
 };
 
+always_inline void
+session_tx_fifo_chain_tail (session_manager_main_t * smm, vlib_main_t * vm,
+			    u8 thread_index, svm_fifo_t * fifo,
+			    vlib_buffer_t * b0, u32 bi0, u8 n_bufs_per_seg,
+			    u32 * left_to_snd0, u16 * n_bufs, u32 * rx_offset,
+			    u16 deq_per_buf, u8 peek_data)
+{
+  vlib_buffer_t *chain_b0, *prev_b0;
+  u32 chain_bi0;
+  u16 len_to_deq0, n_bytes_read;
+  u8 *data0, j;
+
+  chain_bi0 = bi0;
+  chain_b0 = b0;
+  for (j = 1; j < n_bufs_per_seg; j++)
+    {
+      prev_b0 = chain_b0;
+      len_to_deq0 = clib_min (*left_to_snd0, deq_per_buf);
+
+      *n_bufs -= 1;
+      chain_bi0 = smm->tx_buffers[thread_index][*n_bufs];
+      _vec_len (smm->tx_buffers[thread_index]) = *n_bufs;
+
+      chain_b0 = vlib_get_buffer (vm, chain_bi0);
+      chain_b0->current_data = 0;
+      data0 = vlib_buffer_get_current (chain_b0);
+      if (peek_data)
+	{
+	  n_bytes_read = svm_fifo_peek (fifo, *rx_offset, len_to_deq0, data0);
+	  *rx_offset += n_bytes_read;
+	}
+      else
+	{
+	  n_bytes_read = svm_fifo_dequeue_nowait (fifo, len_to_deq0, data0);
+	}
+      ASSERT (n_bytes_read == len_to_deq0);
+      chain_b0->current_length = n_bytes_read;
+      b0->total_length_not_including_first_buffer += chain_b0->current_length;
+
+      /* update previous buffer */
+      prev_b0->next_buffer = chain_bi0;
+      prev_b0->flags |= VLIB_BUFFER_NEXT_PRESENT;
+
+      /* update current buffer */
+      chain_b0->next_buffer = 0;
+
+      *left_to_snd0 -= n_bytes_read;
+      if (*left_to_snd0 == 0)
+	break;
+    }
+}
+
 always_inline int
 session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
 				session_manager_main_t * smm,
@@ -78,16 +130,17 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
 				int *n_tx_packets, u8 peek_data)
 {
   u32 n_trace = vlib_get_trace_count (vm, node);
-  u32 left_to_snd0, max_len_to_snd0, len_to_deq0, n_bufs, snd_space0;
-  u32 n_frame_bytes, n_frames_per_evt;
+  u32 left_to_snd0, max_len_to_snd0, len_to_deq0, snd_space0;
+  u32 n_bufs_per_evt, n_frames_per_evt;
   transport_connection_t *tc0;
   transport_proto_vft_t *transport_vft;
   u32 next_index, next0, *to_next, n_left_to_next, bi0;
   vlib_buffer_t *b0;
-  u32 rx_offset = 0, max_dequeue0;
-  u16 snd_mss0;
+  u32 rx_offset = 0, max_dequeue0, n_bytes_per_seg;
+  u16 snd_mss0, n_bufs_per_seg, n_bufs;
   u8 *data0;
   int i, n_bytes_read;
+  u32 n_bytes_per_buf, deq_per_buf;
 
   next_index = next0 = session_type_to_next[s0->session_type];
 
@@ -134,8 +187,15 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
       max_len_to_snd0 = snd_space0;
     }
 
-  n_frame_bytes = snd_mss0 * VLIB_FRAME_SIZE;
-  n_frames_per_evt = ceil ((double) max_len_to_snd0 / n_frame_bytes);
+  n_bytes_per_buf = vlib_buffer_free_list_buffer_size (vm,
+						       VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
+  n_bytes_per_seg = MAX_HDRS_LEN + snd_mss0;
+  n_bufs_per_seg = ceil ((double) n_bytes_per_seg / n_bytes_per_buf);
+  n_bufs_per_evt = (ceil ((double) max_len_to_snd0 / n_bytes_per_seg))
+    * n_bufs_per_seg;
+  n_frames_per_evt = ceil ((double) n_bufs_per_evt / VLIB_FRAME_SIZE);
+
+  deq_per_buf = clib_min (snd_mss0, n_bytes_per_buf);
 
   n_bufs = vec_len (smm->tx_buffers[thread_index]);
   left_to_snd0 = max_len_to_snd0;
@@ -146,9 +206,9 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
 	{
 	  vec_validate (smm->tx_buffers[thread_index],
 			n_bufs + VLIB_FRAME_SIZE - 1);
-	  n_bufs +=
-	    vlib_buffer_alloc (vm, &smm->tx_buffers[thread_index][n_bufs],
-			       VLIB_FRAME_SIZE);
+	  n_bufs += vlib_buffer_alloc (vm,
+				       &smm->tx_buffers[thread_index][n_bufs],
+				       VLIB_FRAME_SIZE);
 
 	  /* buffer shortage
 	   * XXX 0.9 because when debugging we might not get a full frame */
@@ -165,11 +225,14 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
 	}
 
       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
-      while (left_to_snd0 && n_left_to_next)
+      while (left_to_snd0 && n_left_to_next >= n_bufs_per_seg)
 	{
+	  /*
+	   * Handle first buffer in chain separately
+	   */
+
 	  /* Get free buffer */
-	  n_bufs--;
-	  bi0 = smm->tx_buffers[thread_index][n_bufs];
+	  bi0 = smm->tx_buffers[thread_index][--n_bufs];
 	  _vec_len (smm->tx_buffers[thread_index]) = n_bufs;
 
 	  b0 = vlib_get_buffer (vm, bi0);
@@ -177,52 +240,19 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
 	  b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID
 	    | VNET_BUFFER_LOCALLY_ORIGINATED;
 	  b0->current_data = 0;
+	  b0->total_length_not_including_first_buffer = 0;
 
 	  /* RX on the local interface. tx in default fib */
 	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0;
 	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 
-	  /* usual speculation, or the enqueue_x1 macro will barf */
-	  to_next[0] = bi0;
-	  to_next += 1;
-	  n_left_to_next -= 1;
-
-	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);
-	  if (PREDICT_FALSE (n_trace > 0))
-	    {
-	      session_queue_trace_t *t0;
-	      vlib_trace_buffer (vm, node, next_index, b0,
-				 1 /* follow_chain */ );
-	      vlib_set_trace_count (vm, node, --n_trace);
-	      t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
-	      t0->session_index = s0->session_index;
-	      t0->server_thread_index = s0->thread_index;
-	    }
+	  len_to_deq0 = clib_min (left_to_snd0, deq_per_buf);
 
-	  len_to_deq0 = (left_to_snd0 < snd_mss0) ? left_to_snd0 : snd_mss0;
-
-	  /* *INDENT-OFF* */
-	  SESSION_EVT_DBG(SESSION_EVT_DEQ, s0, ({
-	      ed->data[0] = e0->event_id;
-	      ed->data[1] = max_dequeue0;
-	      ed->data[2] = len_to_deq0;
-	      ed->data[3] = left_to_snd0;
-	  }));
-	  /* *INDENT-ON* */
-
-	  /* Make room for headers */
 	  data0 = vlib_buffer_make_headroom (b0, MAX_HDRS_LEN);
-
-	  /* Dequeue the data
-	   * TODO 1) peek instead of dequeue
-	   *      2) buffer chains */
 	  if (peek_data)
 	    {
 	      n_bytes_read = svm_fifo_peek (s0->server_tx_fifo, rx_offset,
 					    len_to_deq0, data0);
-	      if (n_bytes_read <= 0)
-		goto dequeue_fail;
-
 	      /* Keep track of progress locally, transport is also supposed to
 	       * increment it independently when pushing the header */
 	      rx_offset += n_bytes_read;
@@ -231,18 +261,56 @@ session_tx_fifo_read_and_snd_i (vlib_main_t * vm, vlib_node_runtime_t * node,
 	    {
 	      n_bytes_read = svm_fifo_dequeue_nowait (s0->server_tx_fifo,
 						      len_to_deq0, data0);
-	      if (n_bytes_read <= 0)
-		goto dequeue_fail;
 	    }
 
-	  b0->current_length = n_bytes_read;
+	  if (n_bytes_read <= 0)
+	    goto dequeue_fail;
 
-	  /* Ask transport to push header */
-	  transport_vft->push_header (tc0, b0);
+	  b0->current_length = n_bytes_read;
 
 	  left_to_snd0 -= n_bytes_read;
 	  *n_tx_packets = *n_tx_packets + 1;
 
+	  /*
+	   * Fill in the remaining buffers in the chain, if any
+	   */
+	  if (PREDICT_FALSE (n_bufs_per_seg > 1))
+	    session_tx_fifo_chain_tail (smm, vm, thread_index,
+					s0->server_tx_fifo, b0, bi0,
+					n_bufs_per_seg, &left_to_snd0,
+					&n_bufs, &rx_offset, deq_per_buf,
+					peek_data);
+
+	  /* Ask transport to push header after current_length and
+	   * total_length_not_including_first_buffer are updated */
+	  transport_vft->push_header (tc0, b0);
+
+	  /* *INDENT-OFF* */
+	  SESSION_EVT_DBG(SESSION_EVT_DEQ, s0, ({
+	      ed->data[0] = e0->event_id;
+	      ed->data[1] = max_dequeue0;
+	      ed->data[2] = len_to_deq0;
+	      ed->data[3] = left_to_snd0;
+	  }));
+	  /* *INDENT-ON* */
+
+	  /* usual speculation, or the enqueue_x1 macro will barf */
+	  to_next[0] = bi0;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+
+	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);
+	  if (PREDICT_FALSE (n_trace > 0))
+	    {
+	      session_queue_trace_t *t0;
+	      vlib_trace_buffer (vm, node, next_index, b0,
+				 1 /* follow_chain */ );
+	      vlib_set_trace_count (vm, node, --n_trace);
+	      t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
+	      t0->session_index = s0->session_index;
+	      t0->server_thread_index = s0->thread_index;
+	    }
+
 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 					   to_next, n_left_to_next,
 					   bi0, next0);