From 97de8a2d2faad42ff6c36807ec1e21bf9a0d9c91 Mon Sep 17 00:00:00 2001
From: Brian Russell <brian@graphiant.com>
Date: Tue, 19 Jan 2021 16:50:56 +0000
Subject: [PATCH] policer: add policer handoff

Add thread handoff for packets being policed. Note that the handoff
currently requires the policer index to be passed in. This is suitable
for use in the ip[46] punt paths where each policer node will only
ever use a single policer. For the more general case, this will be
expanded in future to use a policer index stored in packet metadata.

Type: improvement
Signed-off-by: Brian Russell <brian@graphiant.com>
Change-Id: I85a0ecbcfb025f8844e763224cd3de1561249aca
---
 src/vnet/policer/police_inlines.h | 67 +++++++++++++++++++++++++++++++++++++++
 src/vnet/policer/policer.c        | 14 ++++++++
 2 files changed, 81 insertions(+)

diff --git a/src/vnet/policer/police_inlines.h b/src/vnet/policer/police_inlines.h
index 64386e6f1bf..afcc7724cef 100644
--- a/src/vnet/policer/police_inlines.h
+++ b/src/vnet/policer/police_inlines.h
@@ -78,6 +78,73 @@ vnet_policer_police (vlib_main_t * vm,
   return act;
 }
 
+typedef enum
+{
+  POLICER_HANDOFF_ERROR_CONGESTION_DROP,
+} policer_handoff_error_t;
+
+typedef struct policer_handoff_trace_t_
+{
+  u32 policer_index;
+  u32 current_worker_index;
+  u32 next_worker_index;
+} policer_handoff_trace_t;
+
+extern u8 *format_policer_handoff_trace (u8 *s, va_list *args);
+
+/* Do worker handoff based on the policer's thread_index */
+static_always_inline uword
+policer_handoff (vlib_main_t *vm, vlib_node_runtime_t *node,
+		 vlib_frame_t *frame, u32 fq_index, u32 policer_index)
+{
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
+  u16 thread_indices[VLIB_FRAME_SIZE], *ti;
+  u32 n_enq, n_left_from, *from;
+  vnet_policer_main_t *pm;
+  policer_read_response_type_st *policer;
+  u32 this_thread, policer_thread;
+
+  pm = &vnet_policer_main;
+  policer = &pm->policers[policer_index];
+  policer_thread = policer->thread_index;
+
+  this_thread = vm->thread_index;
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  vlib_get_buffers (vm, from, bufs, n_left_from);
+
+  b = bufs;
+  ti = thread_indices;
+
+  while (n_left_from > 0)
+    {
+      ti[0] = policer_thread;
+
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
+			 b[0]->flags & VLIB_BUFFER_IS_TRACED))
+	{
+	  policer_handoff_trace_t *t =
+	    vlib_add_trace (vm, node, b[0], sizeof (*t));
+	  t->current_worker_index = this_thread;
+	  t->next_worker_index = policer_thread;
+	  t->policer_index = policer_index;
+	}
+
+      n_left_from--;
+      ti++;
+      b++;
+    }
+
+  n_enq = vlib_buffer_enqueue_to_thread (vm, fq_index, from, thread_indices,
+					 frame->n_vectors, 1);
+
+  if (n_enq < frame->n_vectors)
+    vlib_node_increment_counter (vm, node->node_index,
+				 POLICER_HANDOFF_ERROR_CONGESTION_DROP,
+				 frame->n_vectors - n_enq);
+
+  return n_enq;
+}
 #endif // __POLICE_INLINES_H__
 
 /*
diff --git a/src/vnet/policer/policer.c b/src/vnet/policer/policer.c
index 7ad87a6ebdf..80fa1e6f68d 100644
--- a/src/vnet/policer/policer.c
+++ b/src/vnet/policer/policer.c
@@ -14,10 +14,24 @@
  */
 #include <stdint.h>
 #include <vnet/policer/policer.h>
+#include <vnet/policer/police_inlines.h>
 #include <vnet/classify/vnet_classify.h>
 
 vnet_policer_main_t vnet_policer_main;
 
+u8 *
+format_policer_handoff_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 *);
+  policer_handoff_trace_t *t = va_arg (*args, policer_handoff_trace_t *);
+
+  s = format (s, "policer %d, handoff thread %d to %d", t->policer_index,
+	      t->current_worker_index, t->next_worker_index);
+
+  return s;
+}
+
 clib_error_t *
 policer_add_del (vlib_main_t * vm,
 		 u8 * name,
-- 
2.16.6