NAT44: do not create session record for identity mapping (VPP-1439)

Change-Id: I39a3146a4e4ba8eadf50af7113b9ae6b1c1d688f
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 35 insertions, 6 deletions

diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index b6106505331..b99aef3944d 100755
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -135,7 +135,7 @@ snat_not_translate (snat_main_t * sm, vlib_node_runtime_t * node,
 			      &value0))
     {
       /* or is static mappings */
-      if (!snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0))
+      if (!snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0, 0))
 	return 0;
     }
   else
@@ -236,13 +236,14 @@ slow_path (snat_main_t * sm, vlib_buffer_t * b0,
 	   vlib_node_runtime_t * node, u32 next0, u32 thread_index, f64 now)
 {
   snat_user_t *u;
-  snat_session_t *s;
+  snat_session_t *s = 0;
   clib_bihash_kv_8_8_t kv0;
   snat_session_key_t key1;
   udp_header_t *udp0 = ip4_next_header (ip0);
   u8 is_sm = 0;
   nat_outside_fib_t *outside_fib;
   fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
+  u8 identity_nat;
   fib_prefix_t pfx = {
     .fp_proto = FIB_PROTOCOL_IP4,
     .fp_len = 32,
@@ -263,7 +264,8 @@ slow_path (snat_main_t * sm, vlib_buffer_t * b0,
   key1.protocol = key0->protocol;
 
   /* First try to match static mapping by local address and port */
-  if (snat_static_mapping_match (sm, *key0, &key1, 0, 0, 0, 0, 0))
+  if (snat_static_mapping_match
+      (sm, *key0, &key1, 0, 0, 0, 0, 0, &identity_nat))
     {
       /* Try to create dynamic translation */
       if (snat_alloc_outside_address_and_port (sm->addresses, rx_fib_index0,
@@ -277,7 +279,15 @@ slow_path (snat_main_t * sm, vlib_buffer_t * b0,
 	}
     }
   else
-    is_sm = 1;
+    {
+      if (PREDICT_FALSE (identity_nat))
+	{
+	  *sessionp = s;
+	  return next0;
+	}
+
+      is_sm = 1;
+    }
 
   u = nat_user_get_or_create (sm, &ip0->src_address, rx_fib_index0,
 			      thread_index);
@@ -489,6 +499,12 @@ icmp_match_in2out_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 
       if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
 	goto out;
+
+      if (!s0)
+	{
+	  dont_translate = 1;
+	  goto out;
+	}
     }
   else
     {
@@ -558,7 +574,8 @@ icmp_match_in2out_fast (snat_main_t * sm, vlib_node_runtime_t * node,
     }
   key0.fib_index = rx_fib_index0;
 
-  if (snat_static_mapping_match (sm, key0, &sm0, 0, &is_addr_only, 0, 0, 0))
+  if (snat_static_mapping_match
+      (sm, key0, &sm0, 0, &is_addr_only, 0, 0, 0, 0))
     {
       if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
 						  IP_PROTOCOL_ICMP,
@@ -987,6 +1004,9 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 				     &s0, node, next0, thread_index, now);
 		  if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
 		    goto trace00;
+
+		  if (PREDICT_FALSE (!s0))
+		    goto trace00;
 		}
 	      else
 		{
@@ -1163,6 +1183,9 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 				     &s1, node, next1, thread_index, now);
 		  if (PREDICT_FALSE (next1 == SNAT_IN2OUT_NEXT_DROP))
 		    goto trace01;
+
+		  if (PREDICT_FALSE (!s1))
+		    goto trace01;
 		}
 	      else
 		{
@@ -1374,6 +1397,9 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 
 		  if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
 		    goto trace0;
+
+		  if (PREDICT_FALSE (!s0))
+		    goto trace0;
 		}
 	      else
 		{
@@ -1717,6 +1743,9 @@ nat44_in2out_reass_node_fn (vlib_main_t * vm,
 		  if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
 		    goto trace0;
 
+		  if (PREDICT_FALSE (!s0))
+		    goto trace0;
+
 		  reass0->sess_index = s0 - per_thread_data->sessions;
 		}
 	      else
@@ -1971,7 +2000,7 @@ snat_in2out_fast_static_map_fn (vlib_main_t * vm,
 	  key0.port = udp0->src_port;
 	  key0.fib_index = rx_fib_index0;
 
-	  if (snat_static_mapping_match (sm, key0, &sm0, 0, 0, 0, 0, 0))
+	  if (snat_static_mapping_match (sm, key0, &sm0, 0, 0, 0, 0, 0, 0))
 	    {
 	      b0->error = node->errors[SNAT_IN2OUT_ERROR_NO_TRANSLATION];
 	      next0 = SNAT_IN2OUT_NEXT_DROP;