Network delay simulator plugin

Change-Id: I4a70c7df8f0cb368a4e1cb16f30eeef5c6058c79
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 228 insertions, 0 deletions

diff --git a/src/plugins/nsim/nsim_input.c b/src/plugins/nsim/nsim_input.c
new file mode 100644
index 00000000000..50dbcb97d6b
--- /dev/null
+++ b/src/plugins/nsim/nsim_input.c
@@ -0,0 +1,228 @@
+/*
+ * nsim.c - skeleton vpp engine plug-in
+ *
+ * Copyright (c) <current-year> <your-organization>
+ * 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 <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vppinfra/error.h>
+#include <nsim/nsim.h>
+
+typedef struct
+{
+  f64 expired;
+  u32 tx_sw_if_index;
+} nsim_tx_trace_t;
+
+#ifndef CLIB_MARCH_VARIANT
+/* packet trace format function */
+static u8 *
+format_nsim_tx_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 *);
+  nsim_tx_trace_t *t = va_arg (*args, nsim_tx_trace_t *);
+
+  s = format (s, "NSIM: tx at %.6f sw_if_index %d",
+	      t->expired, t->tx_sw_if_index);
+  return s;
+}
+#endif /* CLIB_MARCH_VARIANT */
+
+vlib_node_registration_t nsim_node;
+
+#define foreach_nsim_tx_error                      \
+_(TX, "Packets transmitted")                    \
+_(DROPPED, "No buffer drops")
+
+typedef enum
+{
+#define _(sym,str) NSIM_TX_ERROR_##sym,
+  foreach_nsim_tx_error
+#undef _
+    NSIM_N_ERROR,
+} nsim_tx_error_t;
+
+#ifndef CLIB_MARCH_VARIANT
+static char *nsim_tx_error_strings[] = {
+#define _(sym,string) string,
+  foreach_nsim_tx_error
+#undef _
+};
+#endif /* CLIB_MARCH_VARIANT */
+
+typedef enum
+{
+  NSIM_NEXT_DROP,
+  NSIM_N_NEXT,
+} nsim_next_t;
+
+always_inline uword
+nsim_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
+		   vlib_frame_t * f, int is_trace)
+{
+  nsim_main_t *nsm = &nsim_main;
+  u32 my_thread_index = vm->thread_index;
+  u32 *my_buffer_cache = nsm->buffer_indices_by_thread[my_thread_index];
+  nsim_wheel_t *wp = nsm->wheel_by_thread[my_thread_index];
+  f64 now = vlib_time_now (vm);
+  uword n_rx_packets = 0;
+  vlib_buffer_t *b0;
+  u32 bi0, next0;
+  vlib_buffer_free_list_t *fl;
+  u32 *to_next;
+  u32 next_index;
+  u32 n_left_to_next;
+  nsim_wheel_entry_t *ep;
+
+  /* Nothing on the scheduler wheel? */
+  if (wp->cursize == 0)
+    return 0;
+
+  /* First entry on the wheel isn't expired? */
+  ep = wp->entries + wp->head;
+  if (ep->tx_time > now)
+    return n_rx_packets;
+
+  /*
+   * We use per-thread buffer caches, so we need the freelist to
+   * initialize them...
+   */
+  fl = vlib_buffer_get_free_list (vm, VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
+  next_index = node->cached_next_index;
+
+  while (wp->cursize)
+    {
+      /* Be aware: this is not the usual coding pattern */
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_to_next > 0 && ep->tx_time <= now)
+	{
+	  /* Out of local buffer cache? */
+	  if (PREDICT_FALSE (_vec_len (my_buffer_cache) == 0))
+	    {
+	      u32 n =
+		vlib_buffer_alloc (vm, my_buffer_cache, VLIB_FRAME_SIZE);
+	      _vec_len (my_buffer_cache) = n;
+
+	      /* Ugh, drop the rest of the expired entries */
+	      if (n == 0)
+		{
+		  u32 drops = 0;
+		  while (ep->tx_time <= now && wp->cursize)
+		    {
+		      wp->head++;
+		      if (wp->head == wp->wheel_size)
+			wp->head = 0;
+		      ep = wp->entries + wp->head;
+		      wp->cursize--;
+		      drops++;
+		    }
+		  /* Count the drops */
+		  vlib_node_increment_counter (vm, node->node_index,
+					       NSIM_TX_ERROR_DROPPED, drops);
+		  /* Ship any pkts we already processed */
+		  vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+		  return n_rx_packets + drops;
+		}
+	    }
+
+	  /* Allocate a buffer */
+	  bi0 = my_buffer_cache[_vec_len (my_buffer_cache) - 1];
+	  _vec_len (my_buffer_cache) -= 1;
+
+	  to_next[0] = bi0;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  /* Initialize the buffer */
+	  vlib_buffer_init_for_free_list (b0, fl);
+
+	  b0->current_data = 0;
+	  b0->current_length = ep->current_length;
+
+	  /* Copy data from the ring */
+	  clib_memcpy (b0->data, ep->data, ep->current_length);
+	  b0->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
+	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = ep->tx_sw_if_index;
+	  vnet_buffer (b0)->sw_if_index[VLIB_RX] =
+	    (ep->tx_sw_if_index == nsm->sw_if_index0) ? nsm->sw_if_index1 :
+	    nsm->sw_if_index0;
+	  next0 = (ep->tx_sw_if_index == nsm->sw_if_index0) ?
+	    nsm->output_next_index0 : nsm->output_next_index1;
+
+	  /* verify speculative enqueue, maybe switch current next frame */
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, next0);
+	  /* Advance to the next ring entry */
+	  wp->head++;
+	  if (wp->head == wp->wheel_size)
+	    wp->head = 0;
+	  wp->cursize--;
+	  ep = wp->entries + wp->head;
+	  n_rx_packets++;
+
+	  /* Out of ring entries? */
+	  if (PREDICT_FALSE (wp->cursize == 0))
+	    break;
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+
+      /* If the current entry hasn't expired, we're done */
+      if (ep->tx_time > now)
+	break;
+    }
+  return n_rx_packets;
+}
+
+VLIB_NODE_FN (nsim_input_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
+				vlib_frame_t * frame)
+{
+  if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
+    return nsim_input_inline (vm, node, frame, 1 /* is_trace */ );
+  else
+    return nsim_input_inline (vm, node, frame, 0 /* is_trace */ );
+
+}
+
+/* *INDENT-OFF* */
+#ifndef CLIB_MARCH_VARIANT
+VLIB_REGISTER_NODE (nsim_input_node) =
+{
+  .type = VLIB_NODE_TYPE_INPUT,
+  .name = "nsim-wheel",
+
+  /* Will be enabled if/when the feature is configured */
+  .state = VLIB_NODE_STATE_DISABLED,
+
+  .format_trace = format_nsim_tx_trace,
+
+  .n_errors = NSIM_N_ERROR,
+  .error_strings = nsim_tx_error_strings,
+};
+#endif /* CLIB_MARCH_VARIANT */
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */