Punt Infra

A punt/exception path that provides:
 1) clients that use the infra
 2) clients can create punt reasons
 3) clients can register to recieve packets that are punted
    for a given reason to be sent to the desired node.
 4) nodes which punt packets fill in the {reason,protocol} of the
    buffere (in the meta-data) and send to the new node "punt-dispatch"
 5) punt-dispatch sends packets to the registered nodes or drops

Change-Id: Ia4f144337f1387cbe585b4f375d0842aefffcde5
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 327 insertions, 0 deletions

diff --git a/src/vlib/punt_node.c b/src/vlib/punt_node.c
new file mode 100644
index 00000000000..c87d2b6fe36
--- /dev/null
+++ b/src/vlib/punt_node.c
@@ -0,0 +1,327 @@
+/*
+ * Copyright (c) 2018 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 <vlib/punt.h>
+
+#define foreach_punt_error                     \
+  _(DISPATCHED, "dispatched")                  \
+  _(NO_REASON, "No such punt reason")          \
+  _(NO_REG, "No registrations")                \
+  _(REP_FAIL, "Replication Faliure")
+
+typedef enum punt_error_t_
+{
+#define _(v,s) PUNT_ERROR_##v,
+  foreach_punt_error
+#undef _
+    PUNT_N_ERRORS,
+} punt_error_t;
+
+static char *punt_error_strings[] = {
+#define _(v,s) [PUNT_ERROR_##v] = s,
+  foreach_punt_error
+#undef _
+};
+
+typedef enum punt_next_t_
+{
+  PUNT_NEXT_DROP,
+  PUNT_N_NEXT,
+} punt_next_t;
+
+typedef struct punt_trace_t_
+{
+  vlib_punt_reason_t pt_reason;
+} punt_trace_t;
+
+/**
+ * Per-thread clone vectors
+ */
+#ifndef CLIB_MARCH_VARIANT
+u32 **punt_clones;
+#else
+extern u32 **punt_clones;
+#endif
+
+static u8 *
+format_punt_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 *);
+  punt_trace_t *t = va_arg (*args, punt_trace_t *);
+
+  s = format (s, "reason: %U", format_vlib_punt_reason, t->pt_reason);
+
+  return s;
+}
+
+always_inline u32
+punt_replicate (vlib_main_t * vm,
+		vlib_node_runtime_t * node,
+		u32 thread_index,
+		vlib_buffer_t * b0,
+		u32 bi0,
+		vlib_punt_reason_t pr0,
+		u32 * next_index,
+		u32 * n_left_to_next, u32 ** to_next, u32 * pkts_rep_fail)
+{
+  /* multiple clients => replicate a copy to each */
+  u16 n_clones0, n_cloned0, clone0;
+  u32 ci0, next0;
+
+  n_clones0 = vec_len (punt_dp_db[pr0]);
+  vec_validate (punt_clones[thread_index], n_clones0);
+
+  n_cloned0 = vlib_buffer_clone (vm, bi0,
+				 punt_clones[thread_index],
+				 n_clones0, 2 * CLIB_CACHE_LINE_BYTES);
+
+  if (PREDICT_FALSE (n_cloned0 != n_clones0))
+    {
+      b0->error = node->errors[PUNT_ERROR_REP_FAIL];
+      *pkts_rep_fail += 1;
+    }
+
+  for (clone0 = 1; clone0 < n_cloned0; clone0++)
+    {
+      ci0 = punt_clones[thread_index][clone0];
+
+      *to_next[0] = ci0;
+      *to_next += 1;
+      *n_left_to_next -= 1;
+
+      next0 = punt_dp_db[pr0][clone0];
+
+      if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	{
+	  vlib_buffer_t *c0;
+	  punt_trace_t *t;
+
+	  c0 = vlib_get_buffer (vm, ci0);
+
+	  if (c0 != b0)
+	    vlib_buffer_copy_trace_flag (vm, b0, ci0);
+
+	  t = vlib_add_trace (vm, node, c0, sizeof (*t));
+	  t->pt_reason = pr0;
+	}
+
+      vlib_validate_buffer_enqueue_x1 (vm, node, *next_index,
+				       *to_next, *n_left_to_next, ci0, next0);
+
+      /* replications here always go to different next-nodes
+       * so there's no need to check if the to_next frame
+       * is full */
+    }
+
+  /* The original buffer is the first clone */
+  next0 = punt_dp_db[pr0][0];
+  *to_next[0] = bi0;
+  return next0;
+}
+
+always_inline u32
+punt_dispatch_one (vlib_main_t * vm,
+		   vlib_node_runtime_t * node,
+		   vlib_combined_counter_main_t * cm,
+		   u32 thread_index,
+		   u32 bi0,
+		   u32 * next_index,
+		   u32 * n_left_to_next, u32 ** to_next, u32 * pkts_errors)
+{
+  vlib_punt_reason_t pr0;
+  vlib_buffer_t *b0;
+  u32 next0;
+
+  b0 = vlib_get_buffer (vm, bi0);
+  pr0 = b0->punt_reason;
+
+  if (PREDICT_FALSE (pr0 >= vec_len (punt_dp_db)))
+    {
+      b0->error = node->errors[PUNT_ERROR_NO_REASON];
+      next0 = PUNT_NEXT_DROP;
+      pkts_errors[PUNT_ERROR_NO_REASON] += 1;
+    }
+  else
+    {
+      vlib_increment_combined_counter
+	(cm, thread_index, pr0, 1, vlib_buffer_length_in_chain (vm, b0));
+
+      if (PREDICT_TRUE (1 == vec_len (punt_dp_db[pr0])))
+	{
+	  /*
+	   * one registered client => give it the packet
+	   * This is the most likely outcome.
+	   */
+	  next0 = punt_dp_db[pr0][0];
+	  pkts_errors[PUNT_ERROR_DISPATCHED] += 1;
+	}
+      else if (0 == vec_len (punt_dp_db[pr0]))
+	{
+	  /* no registered clients => drop */
+	  next0 = PUNT_NEXT_DROP;
+	  pkts_errors[PUNT_ERROR_NO_REG] += 1;
+	}
+      else
+	{
+	  /*
+	   * multiple registered clients => replicate
+	   */
+	  pkts_errors[PUNT_ERROR_DISPATCHED] += 1;
+
+	  next0 = punt_replicate (vm, node, thread_index, b0, bi0, pr0,
+				  next_index, n_left_to_next, to_next,
+				  &pkts_errors[PUNT_ERROR_REP_FAIL]);
+	}
+    }
+
+  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+    {
+      punt_trace_t *t;
+
+      t = vlib_add_trace (vm, node, b0, sizeof (*t));
+      t->pt_reason = pr0;
+    }
+
+  return (next0);
+}
+
+VLIB_NODE_FN (punt_dispatch_node) (vlib_main_t * vm,
+				   vlib_node_runtime_t * node,
+				   vlib_frame_t * frame)
+{
+  u32 n_left_from, *from, *to_next, next_index, thread_index;
+  vlib_combined_counter_main_t *cm;
+  u32 pkt_errors[PUNT_N_ERRORS] = { 0 };
+
+  cm = &punt_counters;
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+  thread_index = vlib_get_thread_index ();
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 4 && n_left_to_next > 2)
+	{
+	  punt_next_t next0, next1;
+	  u32 bi0, bi1;
+
+	  {
+	    vlib_buffer_t *b2, *b3;
+
+	    b2 = vlib_get_buffer (vm, from[2]);
+	    b3 = vlib_get_buffer (vm, from[3]);
+
+	    vlib_prefetch_buffer_header (b2, LOAD);
+	    vlib_prefetch_buffer_header (b3, LOAD);
+	  }
+
+	  bi0 = to_next[0] = from[0];
+	  bi1 = to_next[1] = from[1];
+	  from += 2;
+	  n_left_from -= 2;
+
+	  next0 = punt_dispatch_one (vm, node, cm, thread_index, bi0,
+				     &next_index, &n_left_to_next,
+				     &to_next, pkt_errors);
+	  next1 = punt_dispatch_one (vm, node, cm, thread_index, bi1,
+				     &next_index, &n_left_to_next,
+				     &to_next, pkt_errors);
+
+	  to_next += 2;
+	  n_left_to_next -= 2;
+
+	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, bi1, next0, next1);
+	}
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  punt_next_t next0;
+	  u32 bi0;
+
+	  bi0 = to_next[0] = from[0];
+	  from += 1;
+	  n_left_from -= 1;
+
+	  next0 = punt_dispatch_one (vm, node, cm, thread_index, bi0,
+				     &next_index, &n_left_to_next,
+				     &to_next, pkt_errors);
+
+	  to_next += 1;
+	  n_left_to_next -= 1;
+
+	  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);
+    }
+
+  vlib_node_increment_counter (vm, node->node_index,
+			       PUNT_ERROR_DISPATCHED,
+			       pkt_errors[PUNT_ERROR_DISPATCHED]);
+  vlib_node_increment_counter (vm, node->node_index,
+			       PUNT_ERROR_NO_REASON,
+			       pkt_errors[PUNT_ERROR_NO_REASON]);
+  vlib_node_increment_counter (vm, node->node_index,
+			       PUNT_ERROR_NO_REG,
+			       pkt_errors[PUNT_ERROR_NO_REG]);
+  vlib_node_increment_counter (vm, node->node_index,
+			       PUNT_ERROR_REP_FAIL,
+			       pkt_errors[PUNT_ERROR_REP_FAIL]);
+
+  return frame->n_vectors;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (punt_dispatch_node) = {
+  .name = "punt-dispatch",
+  .vector_size = sizeof (u32),
+  .format_trace = format_punt_trace,
+  .n_errors = PUNT_N_ERRORS,
+  .error_strings = punt_error_strings,
+  .n_next_nodes = PUNT_N_NEXT,
+  .next_nodes = {
+    [PUNT_NEXT_DROP] = "drop",
+  },
+};
+
+/* *INDENT-ON* */
+
+#ifndef CLIB_MARCH_VARIANT
+clib_error_t *
+punt_node_init (vlib_main_t * vm)
+{
+  vec_validate (punt_clones, vlib_num_workers ());
+
+  return NULL;
+}
+
+VLIB_INIT_FUNCTION (punt_node_init);
+#endif
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */