Drop IPsec packets when interface is down

Packets arriving on an IPsec tunnel interface
are decrypted and forwarded even if the
interface is down.

Check interface flags. If the interface is down,
cause packet to be dropped and increment the
counters for drops.

Change-Id: I94456bda3bd8eade0f3f522ad7cc341251174e6e
Signed-off-by: Matthew Smith <mgsmith@netgate.com>

1 files changed, 32 insertions, 10 deletions

diff --git a/src/vnet/ipsec/ipsec_if_in.c b/src/vnet/ipsec/ipsec_if_in.c
index 2627e7c1ca6..655668abc1d 100644
--- a/src/vnet/ipsec/ipsec_if_in.c
+++ b/src/vnet/ipsec/ipsec_if_in.c
@@ -23,8 +23,9 @@
 #include <vnet/ipsec/esp.h>
 
 /* Statistics (not really errors) */
-#define foreach_ipsec_if_input_error    \
-_(RX, "good packets received")
+#define foreach_ipsec_if_input_error				  \
+_(RX, "good packets received")					  \
+_(DISABLED, "ipsec packets received on disabled interface")
 
 static char *ipsec_if_input_error_strings[] = {
 #define _(sym,string) string,
@@ -73,6 +74,12 @@ ipsec_if_input_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
   u8 icv_len;
   ipsec_tunnel_if_t *last_t = NULL;
   ipsec_sa_t *sa0;
+  vlib_combined_counter_main_t *rx_counter;
+  vlib_combined_counter_main_t *drop_counter;
+  u32 n_disabled = 0;
+
+  rx_counter = vim->combined_sw_if_counters + VNET_INTERFACE_COUNTER_RX;
+  drop_counter = vim->combined_sw_if_counters + VNET_INTERFACE_COUNTER_DROP;
 
   from = vlib_frame_vector_args (from_frame);
   n_left_from = from_frame->n_vectors;
@@ -91,6 +98,7 @@ ipsec_if_input_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 	  ip4_header_t *ip0;
 	  esp_header_t *esp0;
 	  uword *p;
+	  u32 len0;
 
 	  bi0 = to_next[0] = from[0];
 	  from += 1;
@@ -108,6 +116,8 @@ ipsec_if_input_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 
 	  p = hash_get (im->ipsec_if_pool_index_by_key, key);
 
+	  len0 = vlib_buffer_length_in_chain (vm, b0);
+
 	  if (p)
 	    {
 	      ipsec_tunnel_if_t *t;
@@ -122,10 +132,20 @@ ipsec_if_input_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 		  sw_if_index0 = hi->sw_if_index;
 		  vnet_buffer (b0)->sw_if_index[VLIB_RX] = sw_if_index0;
 
+		  if (PREDICT_FALSE
+		      (!(hi->flags & VNET_HW_INTERFACE_FLAG_LINK_UP)))
+		    {
+		      vlib_increment_combined_counter
+			(drop_counter, thread_index, sw_if_index0, 1, len0);
+		      b0->error = node->errors[IPSEC_IF_INPUT_ERROR_DISABLED];
+		      n_disabled++;
+		      goto trace;
+		    }
+
 		  if (PREDICT_TRUE (sw_if_index0 == last_sw_if_index))
 		    {
 		      n_packets++;
-		      n_bytes += vlib_buffer_length_in_chain (vm, b0);
+		      n_bytes += len0;
 		    }
 		  else
 		    {
@@ -143,15 +163,14 @@ ipsec_if_input_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 		      if (last_t)
 			{
 			  vlib_increment_combined_counter
-			    (vim->combined_sw_if_counters
-			     + VNET_INTERFACE_COUNTER_RX,
-			     thread_index, sw_if_index0, n_packets, n_bytes);
+			    (rx_counter, thread_index, sw_if_index0,
+			     n_packets, n_bytes);
 			}
 
 		      last_sw_if_index = sw_if_index0;
 		      last_t = t;
 		      n_packets = 1;
-		      n_bytes = vlib_buffer_length_in_chain (vm, b0);
+		      n_bytes = len0;
 		    }
 		}
 	      else
@@ -163,6 +182,7 @@ ipsec_if_input_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 	      next0 = im->esp_decrypt_next_index;
 	    }
 
+	trace:
 	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 	    {
 	      ipsec_if_input_trace_t *tr =
@@ -185,15 +205,17 @@ ipsec_if_input_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
       n_bytes -= n_packets * (sizeof (ip4_header_t) + sizeof (esp_header_t) +
 			      sizeof (esp_footer_t) + 16 /* aes-cbc IV */  +
 			      icv_len);
-      vlib_increment_combined_counter (vim->combined_sw_if_counters
-				       + VNET_INTERFACE_COUNTER_RX,
+      vlib_increment_combined_counter (rx_counter,
 				       thread_index,
 				       last_sw_if_index, n_packets, n_bytes);
     }
 
   vlib_node_increment_counter (vm, ipsec_if_input_node.index,
 			       IPSEC_IF_INPUT_ERROR_RX,
-			       from_frame->n_vectors);
+			       from_frame->n_vectors - n_disabled);
+
+  vlib_node_increment_counter (vm, ipsec_if_input_node.index,
+			       IPSEC_IF_INPUT_ERROR_DISABLED, n_disabled);
 
   return from_frame->n_vectors;
 }