Cleanup/refactor session layer code

Change-Id: Ica99e8cb919fca6b069c37c969d60e8ccc2c6bf9
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 685 insertions, 0 deletions

diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
new file mode 100644
index 00000000000..8d703b0b302
--- /dev/null
+++ b/src/vnet/session/session_node.c
@@ -0,0 +1,685 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <math.h>
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/tcp/tcp.h>
+#include <vppinfra/elog.h>
+#include <vnet/session/application.h>
+#include <vnet/session/session_debug.h>
+#include <vlibmemory/unix_shared_memory_queue.h>
+
+vlib_node_registration_t session_queue_node;
+
+typedef struct
+{
+  u32 session_index;
+  u32 server_thread_index;
+} session_queue_trace_t;
+
+/* packet trace format function */
+static u8 *
+format_session_queue_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  session_queue_trace_t *t = va_arg (*args, session_queue_trace_t *);
+
+  s = format (s, "SESSION_QUEUE: session index %d, server thread index %d",
+	      t->session_index, t->server_thread_index);
+  return s;
+}
+
+vlib_node_registration_t session_queue_node;
+
+#define foreach_session_queue_error		\
+_(TX, "Packets transmitted")                  	\
+_(TIMER, "Timer events")			\
+_(NO_BUFFER, "Out of buffers")
+
+typedef enum
+{
+#define _(sym,str) SESSION_QUEUE_ERROR_##sym,
+  foreach_session_queue_error
+#undef _
+    SESSION_QUEUE_N_ERROR,
+} session_queue_error_t;
+
+static char *session_queue_error_strings[] = {
+#define _(sym,string) string,
+  foreach_session_queue_error
+#undef _
+};
+
+static u32 session_type_to_next[] = {
+  SESSION_QUEUE_NEXT_TCP_IP4_OUTPUT,
+  SESSION_QUEUE_NEXT_IP4_LOOKUP,
+  SESSION_QUEUE_NEXT_TCP_IP6_OUTPUT,
+  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,
+				session_fifo_event_t * e0,
+				stream_session_t * s0, u32 thread_index,
+				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, 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, 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;
+  u32 buffers_allocated, buffers_allocated_this_call;
+
+  next_index = next0 = session_type_to_next[s0->session_type];
+
+  transport_vft = session_get_transport_vft (s0->session_type);
+  tc0 = transport_vft->get_connection (s0->connection_index, thread_index);
+
+  /* Make sure we have space to send and there's something to dequeue */
+  snd_mss0 = transport_vft->send_mss (tc0);
+  snd_space0 = transport_vft->send_space (tc0);
+
+  /* Can't make any progress */
+  if (snd_space0 == 0 || snd_mss0 == 0)
+    {
+      vec_add1 (smm->pending_event_vector[thread_index], *e0);
+      return 0;
+    }
+
+  if (peek_data)
+    {
+      /* Offset in rx fifo from where to peek data  */
+      rx_offset = transport_vft->tx_fifo_offset (tc0);
+    }
+
+  /* Check how much we can pull. If buffering, subtract the offset */
+  max_dequeue0 = svm_fifo_max_dequeue (s0->server_tx_fifo) - rx_offset;
+
+  /* Nothing to read return */
+  if (max_dequeue0 == 0)
+    {
+      svm_fifo_unset_event (s0->server_tx_fifo);
+      return 0;
+    }
+
+  /* Ensure we're not writing more than transport window allows */
+  if (max_dequeue0 < snd_space0)
+    {
+      /* Constrained by tx queue. Try to send only fully formed segments */
+      max_len_to_snd0 = (max_dequeue0 > snd_mss0) ?
+	max_dequeue0 - max_dequeue0 % snd_mss0 : max_dequeue0;
+      /* TODO Nagle ? */
+    }
+  else
+    {
+      max_len_to_snd0 = snd_space0;
+    }
+
+  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;
+  for (i = 0; i < n_frames_per_evt; i++)
+    {
+      /* Make sure we have at least one full frame of buffers ready */
+      if (PREDICT_FALSE (n_bufs < VLIB_FRAME_SIZE))
+	{
+	  vec_validate (smm->tx_buffers[thread_index],
+			n_bufs + 2 * VLIB_FRAME_SIZE - 1);
+
+	  buffers_allocated = 0;
+	  do
+	    {
+	      buffers_allocated_this_call =
+		vlib_buffer_alloc
+		(vm,
+		 &smm->tx_buffers[thread_index][n_bufs + buffers_allocated],
+		 2 * VLIB_FRAME_SIZE - buffers_allocated);
+	      buffers_allocated += buffers_allocated_this_call;
+	    }
+	  while (buffers_allocated_this_call > 0
+		 && ((buffers_allocated + n_bufs < VLIB_FRAME_SIZE)));
+
+	  n_bufs += buffers_allocated;
+
+	  _vec_len (smm->tx_buffers[thread_index]) = n_bufs;
+
+	  if (PREDICT_FALSE (n_bufs < VLIB_FRAME_SIZE))
+	    {
+	      vec_add1 (smm->pending_event_vector[thread_index], *e0);
+	      return -1;
+	    }
+	}
+      /* Allow enqueuing of a new event */
+      svm_fifo_unset_event (s0->server_tx_fifo);
+
+      vlib_get_next_frame (vm, node, next_index, to_next, 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 */
+	  ASSERT (n_bufs >= 1);
+	  bi0 = smm->tx_buffers[thread_index][--n_bufs];
+	  ASSERT (bi0);
+	  _vec_len (smm->tx_buffers[thread_index]) = n_bufs;
+
+	  /* usual speculation, or the enqueue_x1 macro will barf */
+	  to_next[0] = bi0;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b0->error = 0;
+	  b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID
+	    | VNET_BUFFER_F_LOCALLY_ORIGINATED;
+	  b0->current_data = 0;
+	  b0->total_length_not_including_first_buffer = 0;
+
+	  len_to_deq0 = clib_min (left_to_snd0, deq_per_buf);
+
+	  data0 = vlib_buffer_make_headroom (b0, MAX_HDRS_LEN);
+	  if (peek_data)
+	    {
+	      n_bytes_read = svm_fifo_peek (s0->server_tx_fifo, rx_offset,
+					    len_to_deq0, data0);
+	      /* Keep track of progress locally, transport is also supposed to
+	       * increment it independently when pushing the header */
+	      rx_offset += n_bytes_read;
+	    }
+	  else
+	    {
+	      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;
+
+	  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* */
+
+
+	  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);
+	}
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  /* If we couldn't dequeue all bytes mark as partially read */
+  if (max_len_to_snd0 < max_dequeue0)
+    {
+      /* If we don't already have new event */
+      if (svm_fifo_set_event (s0->server_tx_fifo))
+	{
+	  vec_add1 (smm->pending_event_vector[thread_index], *e0);
+	}
+    }
+  return 0;
+
+dequeue_fail:
+  /*
+   * Can't read from fifo. If we don't already have an event, save as partially
+   * read, return buff to free list and return
+   */
+  clib_warning ("dequeue fail");
+
+  if (svm_fifo_set_event (s0->server_tx_fifo))
+    {
+      vec_add1 (smm->pending_event_vector[thread_index], *e0);
+    }
+  vlib_put_next_frame (vm, node, next_index, n_left_to_next + 1);
+  _vec_len (smm->tx_buffers[thread_index]) += 1;
+
+  return 0;
+}
+
+int
+session_tx_fifo_peek_and_snd (vlib_main_t * vm, vlib_node_runtime_t * node,
+			      session_manager_main_t * smm,
+			      session_fifo_event_t * e0,
+			      stream_session_t * s0, u32 thread_index,
+			      int *n_tx_pkts)
+{
+  return session_tx_fifo_read_and_snd_i (vm, node, smm, e0, s0, thread_index,
+					 n_tx_pkts, 1);
+}
+
+int
+session_tx_fifo_dequeue_and_snd (vlib_main_t * vm, vlib_node_runtime_t * node,
+				 session_manager_main_t * smm,
+				 session_fifo_event_t * e0,
+				 stream_session_t * s0, u32 thread_index,
+				 int *n_tx_pkts)
+{
+  return session_tx_fifo_read_and_snd_i (vm, node, smm, e0, s0, thread_index,
+					 n_tx_pkts, 0);
+}
+
+always_inline stream_session_t *
+session_event_get_session (session_fifo_event_t * e, u8 thread_index)
+{
+  ASSERT (e->fifo->master_thread_index == thread_index);
+  return stream_session_get_if_valid (e->fifo->master_session_index,
+				      thread_index);
+}
+
+void
+dump_thread_0_event_queue (void)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  vlib_main_t *vm = &vlib_global_main;
+  u32 my_thread_index = vm->thread_index;
+  session_fifo_event_t _e, *e = &_e;
+  stream_session_t *s0;
+  int i, index;
+  i8 *headp;
+
+  unix_shared_memory_queue_t *q;
+  q = smm->vpp_event_queues[my_thread_index];
+
+  index = q->head;
+
+  for (i = 0; i < q->cursize; i++)
+    {
+      headp = (i8 *) (&q->data[0] + q->elsize * index);
+      clib_memcpy (e, headp, q->elsize);
+
+      switch (e->event_type)
+	{
+	case FIFO_EVENT_APP_TX:
+	  s0 = session_event_get_session (e, my_thread_index);
+	  fformat (stdout, "[%04d] TX session %d\n", i, s0->session_index);
+	  break;
+
+	case FIFO_EVENT_DISCONNECT:
+	  s0 = stream_session_get_from_handle (e->session_handle);
+	  fformat (stdout, "[%04d] disconnect session %d\n", i,
+		   s0->session_index);
+	  break;
+
+	case FIFO_EVENT_BUILTIN_RX:
+	  s0 = session_event_get_session (e, my_thread_index);
+	  fformat (stdout, "[%04d] builtin_rx %d\n", i, s0->session_index);
+	  break;
+
+	case FIFO_EVENT_RPC:
+	  fformat (stdout, "[%04d] RPC call %llx with %llx\n",
+		   i, (u64) (e->rpc_args.fp), (u64) (e->rpc_args.arg));
+	  break;
+
+	default:
+	  fformat (stdout, "[%04d] unhandled event type %d\n",
+		   i, e->event_type);
+	  break;
+	}
+
+      index++;
+
+      if (index == q->maxsize)
+	index = 0;
+    }
+}
+
+static u8
+session_node_cmp_event (session_fifo_event_t * e, svm_fifo_t * f)
+{
+  stream_session_t *s;
+  switch (e->event_type)
+    {
+    case FIFO_EVENT_APP_RX:
+    case FIFO_EVENT_APP_TX:
+    case FIFO_EVENT_BUILTIN_RX:
+      if (e->fifo == f)
+	return 1;
+      break;
+    case FIFO_EVENT_DISCONNECT:
+      break;
+    case FIFO_EVENT_RPC:
+      s = stream_session_get_from_handle (e->session_handle);
+      if (!s)
+	{
+	  clib_warning ("session has event but doesn't exist!");
+	  break;
+	}
+      if (s->server_rx_fifo == f || s->server_tx_fifo == f)
+	return 1;
+      break;
+    default:
+      break;
+    }
+  return 0;
+}
+
+u8
+session_node_lookup_fifo_event (svm_fifo_t * f, session_fifo_event_t * e)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  unix_shared_memory_queue_t *q;
+  session_fifo_event_t *pending_event_vector, *evt;
+  int i, index, found = 0;
+  i8 *headp;
+  u8 thread_index;
+
+  ASSERT (e);
+  thread_index = f->master_thread_index;
+  /*
+   * Search evt queue
+   */
+  q = smm->vpp_event_queues[thread_index];
+  index = q->head;
+  for (i = 0; i < q->cursize; i++)
+    {
+      headp = (i8 *) (&q->data[0] + q->elsize * index);
+      clib_memcpy (e, headp, q->elsize);
+      found = session_node_cmp_event (e, f);
+      if (found)
+	break;
+      if (++index == q->maxsize)
+	index = 0;
+    }
+  /*
+   * Search pending events vector
+   */
+  pending_event_vector = smm->pending_event_vector[thread_index];
+  vec_foreach (evt, pending_event_vector)
+  {
+    found = session_node_cmp_event (evt, f);
+    if (found)
+      {
+	clib_memcpy (e, evt, sizeof (*evt));
+	break;
+      }
+  }
+  return found;
+}
+
+static uword
+session_queue_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
+		       vlib_frame_t * frame)
+{
+  session_manager_main_t *smm = vnet_get_session_manager_main ();
+  session_fifo_event_t *my_pending_event_vector, *e;
+  session_fifo_event_t *my_fifo_events;
+  u32 n_to_dequeue, n_events;
+  unix_shared_memory_queue_t *q;
+  application_t *app;
+  int n_tx_packets = 0;
+  u32 my_thread_index = vm->thread_index;
+  int i, rv;
+  f64 now = vlib_time_now (vm);
+  void (*fp) (void *);
+
+  SESSION_EVT_DBG (SESSION_EVT_POLL_GAP_TRACK, smm, my_thread_index);
+
+  /*
+   *  Update TCP time
+   */
+  tcp_update_time (now, my_thread_index);
+
+  /*
+   * Get vpp queue events
+   */
+  q = smm->vpp_event_queues[my_thread_index];
+  if (PREDICT_FALSE (q == 0))
+    return 0;
+
+  my_fifo_events = smm->free_event_vector[my_thread_index];
+
+  /* min number of events we can dequeue without blocking */
+  n_to_dequeue = q->cursize;
+  my_pending_event_vector = smm->pending_event_vector[my_thread_index];
+
+  if (n_to_dequeue == 0 && vec_len (my_pending_event_vector) == 0)
+    return 0;
+
+  SESSION_EVT_DBG (SESSION_EVT_DEQ_NODE, 0);
+
+  /*
+   * If we didn't manage to process previous events try going
+   * over them again without dequeuing new ones.
+   */
+  /* XXX: Block senders to sessions that can't keep up */
+  if (0 && vec_len (my_pending_event_vector) >= 100)
+    {
+      clib_warning ("too many fifo events unsolved");
+      goto skip_dequeue;
+    }
+
+  /* See you in the next life, don't be late */
+  if (pthread_mutex_trylock (&q->mutex))
+    return 0;
+
+  for (i = 0; i < n_to_dequeue; i++)
+    {
+      vec_add2 (my_fifo_events, e, 1);
+      unix_shared_memory_queue_sub_raw (q, (u8 *) e);
+    }
+
+  /* The other side of the connection is not polling */
+  if (q->cursize < (q->maxsize / 8))
+    (void) pthread_cond_broadcast (&q->condvar);
+  pthread_mutex_unlock (&q->mutex);
+
+  vec_append (my_fifo_events, my_pending_event_vector);
+
+  _vec_len (my_pending_event_vector) = 0;
+  smm->pending_event_vector[my_thread_index] = my_pending_event_vector;
+
+skip_dequeue:
+  n_events = vec_len (my_fifo_events);
+  for (i = 0; i < n_events; i++)
+    {
+      stream_session_t *s0;	/* $$$ prefetch 1 ahead maybe */
+      session_fifo_event_t *e0;
+
+      e0 = &my_fifo_events[i];
+
+      switch (e0->event_type)
+	{
+	case FIFO_EVENT_APP_TX:
+	  s0 = session_event_get_session (e0, my_thread_index);
+
+	  if (CLIB_DEBUG && !s0)
+	    {
+	      clib_warning ("It's dead, Jim!");
+	      continue;
+	    }
+
+	  if (PREDICT_FALSE (s0->session_state == SESSION_STATE_CLOSED))
+	    continue;
+	  /* Spray packets in per session type frames, since they go to
+	   * different nodes */
+	  rv = (smm->session_tx_fns[s0->session_type]) (vm, node, smm, e0, s0,
+							my_thread_index,
+							&n_tx_packets);
+	  /* Out of buffers */
+	  if (PREDICT_FALSE (rv < 0))
+	    {
+	      vlib_node_increment_counter (vm, node->node_index,
+					   SESSION_QUEUE_ERROR_NO_BUFFER, 1);
+	      continue;
+	    }
+	  break;
+	case FIFO_EVENT_DISCONNECT:
+	  s0 = stream_session_get_from_handle (e0->session_handle);
+	  stream_session_disconnect (s0);
+	  break;
+	case FIFO_EVENT_BUILTIN_RX:
+	  s0 = session_event_get_session (e0, my_thread_index);
+	  svm_fifo_unset_event (s0->server_rx_fifo);
+	  app = application_get (s0->app_index);
+	  app->cb_fns.builtin_server_rx_callback (s0);
+	  break;
+	case FIFO_EVENT_RPC:
+	  fp = e0->rpc_args.fp;
+	  (*fp) (e0->rpc_args.arg);
+	  break;
+
+	default:
+	  clib_warning ("unhandled event type %d", e0->event_type);
+	}
+    }
+
+  _vec_len (my_fifo_events) = 0;
+  smm->free_event_vector[my_thread_index] = my_fifo_events;
+
+  vlib_node_increment_counter (vm, session_queue_node.index,
+			       SESSION_QUEUE_ERROR_TX, n_tx_packets);
+
+  SESSION_EVT_DBG (SESSION_EVT_DEQ_NODE, 1);
+
+  return n_tx_packets;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (session_queue_node) =
+{
+  .function = session_queue_node_fn,
+  .name = "session-queue",
+  .format_trace = format_session_queue_trace,
+  .type = VLIB_NODE_TYPE_INPUT,
+  .n_errors = ARRAY_LEN (session_queue_error_strings),
+  .error_strings = session_queue_error_strings,
+  .n_next_nodes = SESSION_QUEUE_N_NEXT,
+  .state = VLIB_NODE_STATE_DISABLED,
+  .next_nodes =
+  {
+      [SESSION_QUEUE_NEXT_DROP] = "error-drop",
+      [SESSION_QUEUE_NEXT_IP4_LOOKUP] = "ip4-lookup",
+      [SESSION_QUEUE_NEXT_IP6_LOOKUP] = "ip6-lookup",
+      [SESSION_QUEUE_NEXT_TCP_IP4_OUTPUT] = "tcp4-output",
+      [SESSION_QUEUE_NEXT_TCP_IP6_OUTPUT] = "tcp6-output",
+  },
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */