at af_packet input, drop partial packets to prevent l4 checksum deadloop at ouptut

Change-Id: I6f75b7328fd0aa71d00a701e36c8b4ad06bff3c4
Signed-off-by: Chaoyu Jin <chjin@cisco.com>

1 files changed, 17 insertions, 4 deletions

diff --git a/src/vnet/devices/af_packet/node.c b/src/vnet/devices/af_packet/node.c
index b627cfcb036..d74e56fd0e9 100644
--- a/src/vnet/devices/af_packet/node.c
+++ b/src/vnet/devices/af_packet/node.c
@@ -29,7 +29,8 @@
 
 #include <vnet/devices/af_packet/af_packet.h>
 
-#define foreach_af_packet_input_error
+#define foreach_af_packet_input_error \
+  _(PARTIAL_PKT, "partial packet")
 
 typedef enum
 {
@@ -292,6 +293,21 @@ af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 	  to_next += 1;
 	  n_left_to_next--;
 
+	  /* drop partial packets */
+	  if (PREDICT_FALSE (tph->tp_len != tph->tp_snaplen))
+	    {
+	      next0 = VNET_DEVICE_INPUT_NEXT_DROP;
+	      first_b0->error =
+		node->errors[AF_PACKET_INPUT_ERROR_PARTIAL_PKT];
+	    }
+	  else
+	    {
+	      next0 = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
+	      /* redirect if feature path enabled */
+	      vnet_feature_start_device_input_x1 (apif->sw_if_index, &next0,
+						  first_b0);
+	    }
+
 	  /* trace */
 	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (first_b0);
 	  if (PREDICT_FALSE (n_trace > 0))
@@ -306,9 +322,6 @@ af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 	      clib_memcpy (&tr->tph, tph, sizeof (struct tpacket2_hdr));
 	    }
 
-	  /* redirect if feature path enabled */
-	  vnet_feature_start_device_input_x1 (apif->sw_if_index, &next0, b0);
-
 	  /* enque and take next packet */
 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 					   n_left_to_next, first_bi0, next0);