udp: fix udp_local length errors accounting

In case of UDP length errors in udp_local node, these errors are
being lost and incomplete header may be advanced by wrong offset.
Fix it with only full packets processing and explicit error set
otherwise. Also, optimize two buffer loop perfomance into fast
path with both buffers are ok and slow path with one or none.

Type: fix
Change-Id: I6b7edc3eb5593981e55d7ae20d753c0fd1549d86
Signed-off-by: Vladislav Grishenko <themiron@yandex-team.ru>

1 files changed, 64 insertions, 31 deletions

diff --git a/src/vnet/udp/udp_local.c b/src/vnet/udp/udp_local.c
index 90a43a270e1..41938b8f1f7 100644
--- a/src/vnet/udp/udp_local.c
+++ b/src/vnet/udp/udp_local.c
@@ -125,9 +125,8 @@ udp46_local_inline (vlib_main_t * vm,
 	  u32 bi0, bi1;
 	  vlib_buffer_t *b0, *b1;
 	  udp_header_t *h0 = 0, *h1 = 0;
-	  u32 i0, i1, dst_port0, dst_port1;
+	  u32 i0, i1, next0, next1;
 	  u32 advance0, advance1;
-	  u32 error0, next0, error1, next1;
 
 	  /* Prefetch next iteration. */
 	  {
@@ -169,72 +168,106 @@ udp46_local_inline (vlib_main_t * vm,
 
 	  if (PREDICT_FALSE (b0->current_length < advance0 + sizeof (*h0)))
 	    {
-	      error0 = UDP_ERROR_LENGTH_ERROR;
+	      b0->error = node->errors[UDP_ERROR_LENGTH_ERROR];
 	      next0 = UDP_LOCAL_NEXT_DROP;
 	    }
 	  else
 	    {
 	      vlib_buffer_advance (b0, advance0);
 	      h0 = vlib_buffer_get_current (b0);
-	      error0 = UDP_ERROR_NONE;
 	      next0 = UDP_LOCAL_NEXT_PUNT;
 	      if (PREDICT_FALSE (clib_net_to_host_u16 (h0->length) >
 				 vlib_buffer_length_in_chain (vm, b0)))
 		{
-		  error0 = UDP_ERROR_LENGTH_ERROR;
+		  b0->error = node->errors[UDP_ERROR_LENGTH_ERROR];
 		  next0 = UDP_LOCAL_NEXT_DROP;
 		}
 	    }
 
 	  if (PREDICT_FALSE (b1->current_length < advance1 + sizeof (*h1)))
 	    {
-	      error1 = UDP_ERROR_LENGTH_ERROR;
+	      b1->error = node->errors[UDP_ERROR_LENGTH_ERROR];
 	      next1 = UDP_LOCAL_NEXT_DROP;
 	    }
 	  else
 	    {
 	      vlib_buffer_advance (b1, advance1);
 	      h1 = vlib_buffer_get_current (b1);
-	      error1 = UDP_ERROR_NONE;
 	      next1 = UDP_LOCAL_NEXT_PUNT;
 	      if (PREDICT_FALSE (clib_net_to_host_u16 (h1->length) >
 				 vlib_buffer_length_in_chain (vm, b1)))
 		{
-		  error1 = UDP_ERROR_LENGTH_ERROR;
+		  b1->error = node->errors[UDP_ERROR_LENGTH_ERROR];
 		  next1 = UDP_LOCAL_NEXT_DROP;
 		}
 	    }
 
 	  /* Index sparse array with network byte order. */
-	  dst_port0 = (error0 == 0) ? h0->dst_port : 0;
-	  dst_port1 = (error1 == 0) ? h1->dst_port : 0;
-	  sparse_vec_index2 (next_by_dst_port, dst_port0, dst_port1, &i0,
-			     &i1);
-	  next0 = (error0 == 0) ? vec_elt (next_by_dst_port, i0) : next0;
-	  next1 = (error1 == 0) ? vec_elt (next_by_dst_port, i1) : next1;
-
-	  if (PREDICT_FALSE (i0 == SPARSE_VEC_INVALID_INDEX ||
-			     next0 == UDP_NO_NODE_SET))
+	  if (PREDICT_TRUE (next0 == UDP_LOCAL_NEXT_PUNT &&
+			    next1 == UDP_LOCAL_NEXT_PUNT))
 	    {
-	      udp_dispatch_error (node, b0, advance0, is_ip4, &next0);
+	      sparse_vec_index2 (next_by_dst_port, h0->dst_port, h1->dst_port,
+				 &i0, &i1);
+	      next0 = vec_elt (next_by_dst_port, i0);
+	      next1 = vec_elt (next_by_dst_port, i1);
+
+	      if (PREDICT_FALSE (i0 == SPARSE_VEC_INVALID_INDEX ||
+				 next0 == UDP_NO_NODE_SET))
+		{
+		  udp_dispatch_error (node, b0, advance0, is_ip4, &next0);
+		}
+	      else
+		{
+		  b0->error = node->errors[UDP_ERROR_NONE];
+		  // advance to the payload
+		  vlib_buffer_advance (b0, sizeof (*h0));
+		}
+
+	      if (PREDICT_FALSE (i1 == SPARSE_VEC_INVALID_INDEX ||
+				 next1 == UDP_NO_NODE_SET))
+		{
+		  udp_dispatch_error (node, b1, advance1, is_ip4, &next1);
+		}
+	      else
+		{
+		  b1->error = node->errors[UDP_ERROR_NONE];
+		  // advance to the payload
+		  vlib_buffer_advance (b1, sizeof (*h1));
+		}
 	    }
-	  else
+	  else if (next0 == UDP_LOCAL_NEXT_PUNT)
 	    {
-	      b0->error = node->errors[UDP_ERROR_NONE];
-	      // advance to the payload
-	      vlib_buffer_advance (b0, sizeof (*h0));
-	    }
+	      i0 = sparse_vec_index (next_by_dst_port, h0->dst_port);
+	      next0 = vec_elt (next_by_dst_port, i0);
 
-	  if (PREDICT_FALSE (i1 == SPARSE_VEC_INVALID_INDEX ||
-			     next1 == UDP_NO_NODE_SET))
-	    {
-	      udp_dispatch_error (node, b1, advance1, is_ip4, &next1);
+	      if (PREDICT_FALSE (i0 == SPARSE_VEC_INVALID_INDEX ||
+				 next0 == UDP_NO_NODE_SET))
+		{
+		  udp_dispatch_error (node, b0, advance0, is_ip4, &next0);
+		}
+	      else
+		{
+		  b0->error = node->errors[UDP_ERROR_NONE];
+		  // advance to the payload
+		  vlib_buffer_advance (b0, sizeof (*h0));
+		}
 	    }
-	  else
+	  else if (next1 == UDP_LOCAL_NEXT_PUNT)
 	    {
-	      b1->error = node->errors[UDP_ERROR_NONE];
-	      // advance to the payload
-	      vlib_buffer_advance (b1, sizeof (*h1));
+	      i1 = sparse_vec_index (next_by_dst_port, h1->dst_port);
+	      next1 = vec_elt (next_by_dst_port, i1);
+
+	      if (PREDICT_FALSE (i1 == SPARSE_VEC_INVALID_INDEX ||
+				 next1 == UDP_NO_NODE_SET))
+		{
+		  udp_dispatch_error (node, b1, advance1, is_ip4, &next1);
+		}
+	      else
+		{
+		  b1->error = node->errors[UDP_ERROR_NONE];
+		  // advance to the payload
+		  vlib_buffer_advance (b1, sizeof (*h1));
+		}
 	    }
 
 	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))