nat: Final NAT44 EI/ED split patch

This patch achieves complete separation of
endpoint-dependent and endpoint-independent IPv4 NAT
features. Some common stuff is also moved to NAT
library.

Type: refactor

Change-Id: I52468b7e2b5ac28958a2baf8e2ea01787322e801
Signed-off-by: Filip Varga <fivarga@cisco.com>

1 files changed, 293 insertions, 314 deletions

diff --git a/src/plugins/nat/nat44-ei/nat44_ei_out2in.c b/src/plugins/nat/nat44-ei/nat44_ei_out2in.c
index ca3c272a26c..1d5ebd33cd5 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei_out2in.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei_out2in.c
@@ -14,41 +14,40 @@
  */
 /**
  * @file
- * @brief NAT44 endpoint-dependent outside to inside network translation
+ * @brief NAT44 EI outside to inside network translation
  */
 
 #include <vlib/vlib.h>
-#include <vnet/vnet.h>
 
+#include <vnet/vnet.h>
 #include <vnet/ip/ip.h>
-#include <vnet/udp/udp_local.h>
 #include <vnet/ethernet/ethernet.h>
+#include <vnet/udp/udp_local.h>
 #include <vnet/fib/ip4_fib.h>
-#include <nat/nat.h>
-#include <nat/lib/ipfix_logging.h>
-#include <nat/nat_inlines.h>
-#include <nat/lib/nat_syslog.h>
-#include <nat/nat44-ei/nat44_ei_inlines.h>
-#include <nat/nat44-ei/nat44_ei.h>
 
 #include <vppinfra/hash.h>
 #include <vppinfra/error.h>
-#include <vppinfra/elog.h>
+
+#include <nat/lib/log.h>
+#include <nat/lib/nat_syslog.h>
+#include <nat/lib/ipfix_logging.h>
+#include <nat/nat44-ei/nat44_ei_inlines.h>
+#include <nat/nat44-ei/nat44_ei.h>
 
 typedef struct
 {
   u32 sw_if_index;
   u32 next_index;
   u32 session_index;
-} snat_out2in_trace_t;
+} nat44_ei_out2in_trace_t;
 
 /* packet trace format function */
 static u8 *
-format_snat_out2in_trace (u8 * s, va_list * args)
+format_nat44_ei_out2in_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 *);
-  snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
+  nat44_ei_out2in_trace_t *t = va_arg (*args, nat44_ei_out2in_trace_t *);
 
   s =
     format (s,
@@ -58,66 +57,67 @@ format_snat_out2in_trace (u8 * s, va_list * args)
 }
 
 static u8 *
-format_snat_out2in_fast_trace (u8 * s, va_list * args)
+format_nat44_ei_out2in_fast_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 *);
-  snat_out2in_trace_t *t = va_arg (*args, snat_out2in_trace_t *);
+  nat44_ei_out2in_trace_t *t = va_arg (*args, nat44_ei_out2in_trace_t *);
 
   s = format (s, "NAT44_OUT2IN_FAST: sw_if_index %d, next index %d",
 	      t->sw_if_index, t->next_index);
   return s;
 }
 
-#define foreach_snat_out2in_error                       \
-_(UNSUPPORTED_PROTOCOL, "unsupported protocol")         \
-_(OUT_OF_PORTS, "out of ports")                         \
-_(BAD_ICMP_TYPE, "unsupported ICMP type")               \
-_(NO_TRANSLATION, "no translation")                     \
-_(MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")   \
-_(CANNOT_CREATE_USER, "cannot create NAT user")
+#define foreach_nat44_ei_out2in_error                                         \
+  _ (UNSUPPORTED_PROTOCOL, "unsupported protocol")                            \
+  _ (OUT_OF_PORTS, "out of ports")                                            \
+  _ (BAD_ICMP_TYPE, "unsupported ICMP type")                                  \
+  _ (NO_TRANSLATION, "no translation")                                        \
+  _ (MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")                      \
+  _ (CANNOT_CREATE_USER, "cannot create NAT user")
 
 typedef enum
 {
-#define _(sym,str) SNAT_OUT2IN_ERROR_##sym,
-  foreach_snat_out2in_error
+#define _(sym, str) NAT44_EI_OUT2IN_ERROR_##sym,
+  foreach_nat44_ei_out2in_error
 #undef _
-    SNAT_OUT2IN_N_ERROR,
-} snat_out2in_error_t;
+    NAT44_EI_OUT2IN_N_ERROR,
+} nat44_ei_out2in_error_t;
 
-static char *snat_out2in_error_strings[] = {
+static char *nat44_ei_out2in_error_strings[] = {
 #define _(sym,string) string,
-  foreach_snat_out2in_error
+  foreach_nat44_ei_out2in_error
 #undef _
 };
 
 typedef enum
 {
-  SNAT_OUT2IN_NEXT_DROP,
-  SNAT_OUT2IN_NEXT_LOOKUP,
-  SNAT_OUT2IN_NEXT_ICMP_ERROR,
-  SNAT_OUT2IN_N_NEXT,
-} snat_out2in_next_t;
+  NAT44_EI_OUT2IN_NEXT_DROP,
+  NAT44_EI_OUT2IN_NEXT_LOOKUP,
+  NAT44_EI_OUT2IN_NEXT_ICMP_ERROR,
+  NAT44_EI_OUT2IN_N_NEXT,
+} nat44_ei_out2in_next_t;
 
 #ifndef CLIB_MARCH_VARIANT
 int
 nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 {
-  snat_main_t *sm = &snat_main;
-  nat44_is_idle_session_ctx_t *ctx = arg;
-  snat_session_t *s;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_is_idle_session_ctx_t *ctx = arg;
+  nat44_ei_session_t *s;
   u64 sess_timeout_time;
-  snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
-						       ctx->thread_index);
+  nat44_ei_main_per_thread_data_t *tnm =
+    vec_elt_at_index (nm->per_thread_data, ctx->thread_index);
   clib_bihash_kv_8_8_t s_kv;
 
-  s = pool_elt_at_index (tsm->sessions, kv->value);
-  sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
+  s = pool_elt_at_index (tnm->sessions, kv->value);
+  sess_timeout_time = s->last_heard + (f64) nat_session_get_timeout (
+					&nm->timeouts, s->nat_proto, s->state);
   if (ctx->now >= sess_timeout_time)
     {
       init_nat_i2o_k (&s_kv, s);
-      if (clib_bihash_add_del_8_8 (&sm->in2out, &s_kv, 0))
-	nat_elog_warn ("out2in key del failed");
+      if (clib_bihash_add_del_8_8 (&nm->in2out, &s_kv, 0))
+	nat_elog_warn (nm, "out2in key del failed");
 
       nat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
 					  s->in2out.addr.as_u32,
@@ -135,12 +135,12 @@ nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 		   s->ext_host_port, s->nat_proto, s->out2in.fib_index,
 		   ctx->thread_index);
 
-      if (!snat_is_session_static (s))
-	snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
-					    &s->out2in.addr, s->out2in.port,
-					    s->nat_proto);
+      if (!nat44_ei_is_session_static (s))
+	nat44_ei_free_outside_address_and_port (
+	  nm->addresses, ctx->thread_index, &s->out2in.addr, s->out2in.port,
+	  s->nat_proto);
 
-      nat44_delete_session (sm, s, ctx->thread_index);
+      nat44_ei_delete_session (nm, s, ctx->thread_index);
       return 1;
     }
 
@@ -154,63 +154,56 @@ nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
  * Create NAT session initiated by host from external network with static
  * mapping.
  *
- * @param sm     NAT main.
+ * @param nm     NAT main.
  * @param b0     Vlib buffer.
  * @param in2out In2out NAT44 session key.
  * @param out2in Out2in NAT44 session key.
  * @param node   Vlib node.
  *
- * @returns SNAT session if successfully created otherwise 0.
+ * @returns NAT44_EI session if successfully created otherwise 0.
  */
-static inline snat_session_t *
-create_session_for_static_mapping (snat_main_t * sm,
-				   vlib_buffer_t * b0,
-				   ip4_address_t i2o_addr,
-				   u16 i2o_port,
-				   u32 i2o_fib_index,
-				   ip4_address_t o2i_addr,
-				   u16 o2i_port,
-				   u32 o2i_fib_index,
-				   nat_protocol_t proto,
-				   vlib_node_runtime_t * node,
-				   u32 thread_index, f64 now)
+static inline nat44_ei_session_t *
+create_session_for_static_mapping (
+  nat44_ei_main_t *nm, vlib_buffer_t *b0, ip4_address_t i2o_addr, u16 i2o_port,
+  u32 i2o_fib_index, ip4_address_t o2i_addr, u16 o2i_port, u32 o2i_fib_index,
+  nat_protocol_t proto, vlib_node_runtime_t *node, u32 thread_index, f64 now)
 {
-  snat_user_t *u;
-  snat_session_t *s;
+  nat44_ei_user_t *u;
+  nat44_ei_session_t *s;
   clib_bihash_kv_8_8_t kv0;
   ip4_header_t *ip0;
   udp_header_t *udp0;
-  nat44_is_idle_session_ctx_t ctx0;
+  nat44_ei_is_idle_session_ctx_t ctx0;
 
-  if (PREDICT_FALSE (nat44_ei_maximum_sessions_exceeded (sm, thread_index)))
+  if (PREDICT_FALSE (nat44_ei_maximum_sessions_exceeded (nm, thread_index)))
     {
-      b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
-      nat_elog_notice ("maximum sessions exceeded");
+      b0->error = node->errors[NAT44_EI_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
+      nat_elog_notice (nm, "maximum sessions exceeded");
       return 0;
     }
 
   ip0 = vlib_buffer_get_current (b0);
   udp0 = ip4_next_header (ip0);
 
-  u = nat_user_get_or_create (sm, &i2o_addr, i2o_fib_index, thread_index);
+  u = nat44_ei_user_get_or_create (nm, &i2o_addr, i2o_fib_index, thread_index);
   if (!u)
     {
-      b0->error = node->errors[SNAT_OUT2IN_ERROR_CANNOT_CREATE_USER];
+      b0->error = node->errors[NAT44_EI_OUT2IN_ERROR_CANNOT_CREATE_USER];
       return 0;
     }
 
-  s = nat_session_alloc_or_recycle (sm, u, thread_index, now);
+  s = nat44_ei_session_alloc_or_recycle (nm, u, thread_index, now);
   if (!s)
     {
-      nat44_delete_user_with_no_session (sm, u, thread_index);
-      nat_elog_warn ("create NAT session failed");
+      nat44_ei_delete_user_with_no_session (nm, u, thread_index);
+      nat_elog_warn (nm, "create NAT session failed");
       return 0;
     }
 
-  s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
+  s->flags |= NAT44_EI_SESSION_FLAG_STATIC_MAPPING;
   s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
   s->ext_host_port = udp0->src_port;
-  user_session_increment (sm, u, 1 /* static */ );
+  nat44_ei_user_session_increment (nm, u, 1 /* static */);
   s->in2out.addr = i2o_addr;
   s->in2out.port = i2o_port;
   s->in2out.fib_index = i2o_fib_index;
@@ -223,16 +216,16 @@ create_session_for_static_mapping (snat_main_t * sm,
   ctx0.now = now;
   ctx0.thread_index = thread_index;
   init_nat_i2o_kv (&kv0, s, thread_index,
-		   s - sm->per_thread_data[thread_index].sessions);
+		   s - nm->per_thread_data[thread_index].sessions);
   if (clib_bihash_add_or_overwrite_stale_8_8 (
-	&sm->in2out, &kv0, nat44_i2o_is_idle_session_cb, &ctx0))
-    nat_elog_notice ("in2out key add failed");
+	&nm->in2out, &kv0, nat44_i2o_is_idle_session_cb, &ctx0))
+    nat_elog_notice (nm, "in2out key add failed");
 
   init_nat_o2i_kv (&kv0, s, thread_index,
-		   s - sm->per_thread_data[thread_index].sessions);
+		   s - nm->per_thread_data[thread_index].sessions);
   if (clib_bihash_add_or_overwrite_stale_8_8 (
-	&sm->out2in, &kv0, nat44_o2i_is_idle_session_cb, &ctx0))
-    nat_elog_notice ("out2in key add failed");
+	&nm->out2in, &kv0, nat44_o2i_is_idle_session_cb, &ctx0))
+    nat_elog_notice (nm, "out2in key add failed");
 
   /* log NAT event */
   nat_ipfix_logging_nat44_ses_create (thread_index,
@@ -255,9 +248,9 @@ create_session_for_static_mapping (snat_main_t * sm,
 }
 
 #ifndef CLIB_MARCH_VARIANT
-static_always_inline snat_out2in_error_t
-icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
-	      ip4_address_t * addr, u16 * port, nat_protocol_t * nat_proto)
+static_always_inline nat44_ei_out2in_error_t
+icmp_get_key (vlib_buffer_t *b, ip4_header_t *ip0, ip4_address_t *addr,
+	      u16 *port, nat_protocol_t *nat_proto)
 {
   icmp46_header_t *icmp0;
   icmp_echo_header_t *echo0, *inner_echo0 = 0;
@@ -293,7 +286,7 @@ icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
 	  *port = ((tcp_udp_header_t *) l4_header)->src_port;
 	  break;
 	default:
-	  return SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
+	  return NAT44_EI_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
 	}
     }
   return -1;			/* success */
@@ -303,7 +296,7 @@ icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
  * Get address and port values to be used for ICMP packet translation
  * and create session if needed
  *
- * @param[in,out] sm             NAT main
+ * @param[in,out] nm             NAT main
  * @param[in,out] node           NAT node runtime
  * @param[in] thread_index       thread index
  * @param[in,out] b0             buffer containing packet to be translated
@@ -315,15 +308,16 @@ icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
  * @param e                      optional parameter
  */
 u32
-icmp_match_out2in_slow (snat_main_t *sm, vlib_node_runtime_t *node,
-			u32 thread_index, vlib_buffer_t *b0, ip4_header_t *ip0,
-			ip4_address_t *addr, u16 *port, u32 *fib_index,
-			nat_protocol_t *proto, snat_session_t **p_s0,
-			u8 *dont_translate)
+nat44_ei_icmp_match_out2in_slow (vlib_node_runtime_t *node, u32 thread_index,
+				 vlib_buffer_t *b0, ip4_header_t *ip0,
+				 ip4_address_t *addr, u16 *port,
+				 u32 *fib_index, nat_protocol_t *proto,
+				 nat44_ei_session_t **p_s0, u8 *dont_translate)
 {
-  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_main_per_thread_data_t *tnm = &nm->per_thread_data[thread_index];
   u32 sw_if_index0;
-  snat_session_t *s0 = 0;
+  nat44_ei_session_t *s0 = 0;
   clib_bihash_kv_8_8_t kv0, value0;
   u8 is_addr_only;
   u32 next0 = ~0;
@@ -340,8 +334,8 @@ icmp_match_out2in_slow (snat_main_t *sm, vlib_node_runtime_t *node,
   err = icmp_get_key (b0, ip0, addr, port, proto);
   if (err != -1)
     {
-      b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
-      next0 = SNAT_OUT2IN_NEXT_DROP;
+      b0->error = node->errors[NAT44_EI_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+      next0 = NAT44_EI_OUT2IN_NEXT_DROP;
       goto out;
     }
 
@@ -350,7 +344,7 @@ icmp_match_out2in_slow (snat_main_t *sm, vlib_node_runtime_t *node,
   u32 mapping_fib_index;
 
   init_nat_k (&kv0, *addr, *port, *fib_index, *proto);
-  if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
+  if (clib_bihash_search_8_8 (&nm->out2in, &kv0, &value0))
     {
       /* Try to match static mapping by external address and port,
          destination address and port in packet */
@@ -358,17 +352,18 @@ icmp_match_out2in_slow (snat_main_t *sm, vlib_node_runtime_t *node,
 	    *addr, *port, *fib_index, *proto, &mapping_addr, &mapping_port,
 	    &mapping_fib_index, 1, &is_addr_only, &identity_nat))
 	{
-	  if (!sm->forwarding_enabled)
+	  if (!nm->forwarding_enabled)
 	    {
 	      /* Don't NAT packet aimed at the intfc address */
-	      if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
-						    ip0->dst_address.as_u32)))
+	      if (PREDICT_FALSE (nat44_ei_is_interface_addr (
+		    nm->ip4_main, node, sw_if_index0,
+		    ip0->dst_address.as_u32)))
 		{
 		  *dont_translate = 1;
 		  goto out;
 		}
-	      b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-	      next0 = SNAT_OUT2IN_NEXT_DROP;
+	      b0->error = node->errors[NAT44_EI_OUT2IN_ERROR_NO_TRANSLATION];
+	      next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 	      goto out;
 	    }
 	  else
@@ -384,8 +379,8 @@ icmp_match_out2in_slow (snat_main_t *sm, vlib_node_runtime_t *node,
 	   && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
 	       ICMP4_echo_request || !is_addr_only)))
 	{
-	  b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
-	  next0 = SNAT_OUT2IN_NEXT_DROP;
+	  b0->error = node->errors[NAT44_EI_OUT2IN_ERROR_BAD_ICMP_TYPE];
+	  next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 	  goto out;
 	}
 
@@ -395,15 +390,13 @@ icmp_match_out2in_slow (snat_main_t *sm, vlib_node_runtime_t *node,
 	  goto out;
 	}
       /* Create session initiated by host from external network */
-      s0 =
-	create_session_for_static_mapping (sm, b0, mapping_addr, mapping_port,
-					   mapping_fib_index, *addr, *port,
-					   *fib_index, *proto, node,
-					   thread_index, vlib_time_now (vm));
+      s0 = create_session_for_static_mapping (
+	nm, b0, mapping_addr, mapping_port, mapping_fib_index, *addr, *port,
+	*fib_index, *proto, node, thread_index, vlib_time_now (vm));
 
       if (!s0)
 	{
-	  next0 = SNAT_OUT2IN_NEXT_DROP;
+	  next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 	  goto out;
 	}
     }
@@ -417,12 +410,12 @@ icmp_match_out2in_slow (snat_main_t *sm, vlib_node_runtime_t *node,
 	   && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 					   reass.icmp_type_or_tcp_flags)))
 	{
-	  b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
-	  next0 = SNAT_OUT2IN_NEXT_DROP;
+	  b0->error = node->errors[NAT44_EI_OUT2IN_ERROR_BAD_ICMP_TYPE];
+	  next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 	  goto out;
 	}
 
-      s0 = pool_elt_at_index (tsm->sessions,
+      s0 = pool_elt_at_index (tnm->sessions,
 			      nat_value_get_session_index (&value0));
     }
 
@@ -440,27 +433,15 @@ out:
 #endif
 
 #ifndef CLIB_MARCH_VARIANT
-/**
- * Get address and port values to be used for ICMP packet translation
- *
- * @param[in] sm                 NAT main
- * @param[in,out] node           NAT node runtime
- * @param[in] thread_index       thread index
- * @param[in,out] b0             buffer containing packet to be translated
- * @param[in,out] ip0            ip header
- * @param[out] p_proto           protocol used for matching
- * @param[out] p_value           address and port after NAT translation
- * @param[out] p_dont_translate  if packet should not be translated
- * @param d                      optional parameter
- * @param e                      optional parameter
- */
 u32
-icmp_match_out2in_fast (snat_main_t *sm, vlib_node_runtime_t *node,
-			u32 thread_index, vlib_buffer_t *b0, ip4_header_t *ip0,
-			ip4_address_t *mapping_addr, u16 *mapping_port,
-			u32 *mapping_fib_index, nat_protocol_t *proto,
-			snat_session_t **p_s0, u8 *dont_translate)
+nat44_ei_icmp_match_out2in_fast (vlib_node_runtime_t *node, u32 thread_index,
+				 vlib_buffer_t *b0, ip4_header_t *ip0,
+				 ip4_address_t *mapping_addr,
+				 u16 *mapping_port, u32 *mapping_fib_index,
+				 nat_protocol_t *proto,
+				 nat44_ei_session_t **p_s0, u8 *dont_translate)
 {
+  nat44_ei_main_t *nm = &nat44_ei_main;
   u32 sw_if_index0;
   u32 rx_fib_index0;
   u8 is_addr_only;
@@ -477,7 +458,7 @@ icmp_match_out2in_fast (snat_main_t *sm, vlib_node_runtime_t *node,
   if (err != -1)
     {
       b0->error = node->errors[err];
-      next0 = SNAT_OUT2IN_NEXT_DROP;
+      next0 = NAT44_EI_OUT2IN_NEXT_DROP;
       goto out;
     }
   if (nat44_ei_static_mapping_match (addr, port, rx_fib_index0, *proto,
@@ -485,13 +466,14 @@ icmp_match_out2in_fast (snat_main_t *sm, vlib_node_runtime_t *node,
 				     mapping_fib_index, 1, &is_addr_only, 0))
     {
       /* Don't NAT packet aimed at the intfc address */
-      if (is_interface_addr (sm, node, sw_if_index0, ip0->dst_address.as_u32))
+      if (nat44_ei_is_interface_addr (nm->ip4_main, node, sw_if_index0,
+				      ip0->dst_address.as_u32))
 	{
 	  *dont_translate = 1;
 	  goto out;
 	}
-      b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-      next0 = SNAT_OUT2IN_NEXT_DROP;
+      b0->error = node->errors[NAT44_EI_OUT2IN_ERROR_NO_TRANSLATION];
+      next0 = NAT44_EI_OUT2IN_NEXT_DROP;
       goto out;
     }
 
@@ -502,8 +484,8 @@ icmp_match_out2in_fast (snat_main_t *sm, vlib_node_runtime_t *node,
        && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
 				       reass.icmp_type_or_tcp_flags)))
     {
-      b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
-      next0 = SNAT_OUT2IN_NEXT_DROP;
+      b0->error = node->errors[NAT44_EI_OUT2IN_ERROR_BAD_ICMP_TYPE];
+      next0 = NAT44_EI_OUT2IN_NEXT_DROP;
       goto out;
     }
 
@@ -512,18 +494,20 @@ out:
 }
 #endif
 
-u32 icmp_out2in (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
-		 icmp46_header_t *icmp0, u32 sw_if_index0, u32 rx_fib_index0,
-		 vlib_node_runtime_t *node, u32 next0, u32 thread_index,
-		 snat_session_t **p_s0);
+u32 nat44_ei_icmp_out2in (vlib_buffer_t *b0, ip4_header_t *ip0,
+			  icmp46_header_t *icmp0, u32 sw_if_index0,
+			  u32 rx_fib_index0, vlib_node_runtime_t *node,
+			  u32 next0, u32 thread_index,
+			  nat44_ei_session_t **p_s0);
 
 #ifndef CLIB_MARCH_VARIANT
 u32
-icmp_out2in (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
-	     icmp46_header_t *icmp0, u32 sw_if_index0, u32 rx_fib_index0,
-	     vlib_node_runtime_t *node, u32 next0, u32 thread_index,
-	     snat_session_t **p_s0)
+nat44_ei_icmp_out2in (vlib_buffer_t *b0, ip4_header_t *ip0,
+		      icmp46_header_t *icmp0, u32 sw_if_index0,
+		      u32 rx_fib_index0, vlib_node_runtime_t *node, u32 next0,
+		      u32 thread_index, nat44_ei_session_t **p_s0)
 {
+  nat44_ei_main_t *nm = &nat44_ei_main;
   icmp_echo_header_t *echo0, *inner_echo0 = 0;
   ip4_header_t *inner_ip0 = 0;
   void *l4_header = 0;
@@ -542,12 +526,22 @@ icmp_out2in (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
 
   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 
-  next0_tmp =
-    sm->icmp_match_out2in_cb (sm, node, thread_index, b0, ip0, &addr, &port,
-			      &fib_index, &proto, p_s0, &dont_translate);
+  if (PREDICT_TRUE (nm->pat))
+    {
+      next0_tmp = nat44_ei_icmp_match_out2in_slow (
+	node, thread_index, b0, ip0, &addr, &port, &fib_index, &proto, p_s0,
+	&dont_translate);
+    }
+  else
+    {
+      next0_tmp = nat44_ei_icmp_match_out2in_fast (
+	node, thread_index, b0, ip0, &addr, &port, &fib_index, &proto, p_s0,
+	&dont_translate);
+    }
+
   if (next0_tmp != ~0)
     next0 = next0_tmp;
-  if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
+  if (next0 == NAT44_EI_OUT2IN_NEXT_DROP || dont_translate)
     goto out;
 
   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
@@ -561,7 +555,7 @@ icmp_out2in (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
       checksum0 = ~ip_csum_fold (sum0);
       if (checksum0 != 0 && checksum0 != 0xffff)
 	{
-	  next0 = SNAT_OUT2IN_NEXT_DROP;
+	  next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 	  goto out;
 	}
     }
@@ -604,7 +598,7 @@ icmp_out2in (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
 
 	  if (!ip4_header_checksum_is_valid (inner_ip0))
 	    {
-	      next0 = SNAT_OUT2IN_NEXT_DROP;
+	      next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 	      goto out;
 	    }
 
@@ -656,47 +650,42 @@ out:
 #endif
 
 static inline u32
-icmp_out2in_slow_path (snat_main_t * sm,
-		       vlib_buffer_t * b0,
-		       ip4_header_t * ip0,
-		       icmp46_header_t * icmp0,
-		       u32 sw_if_index0,
-		       u32 rx_fib_index0,
-		       vlib_node_runtime_t * node,
-		       u32 next0, f64 now,
-		       u32 thread_index, snat_session_t ** p_s0)
+nat44_ei_icmp_out2in_slow_path (nat44_ei_main_t *nm, vlib_buffer_t *b0,
+				ip4_header_t *ip0, icmp46_header_t *icmp0,
+				u32 sw_if_index0, u32 rx_fib_index0,
+				vlib_node_runtime_t *node, u32 next0, f64 now,
+				u32 thread_index, nat44_ei_session_t **p_s0)
 {
   vlib_main_t *vm = vlib_get_main ();
 
-  next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-		       next0, thread_index, p_s0);
-  snat_session_t *s0 = *p_s0;
-  if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP && s0))
+  next0 = nat44_ei_icmp_out2in (b0, ip0, icmp0, sw_if_index0, rx_fib_index0,
+				node, next0, thread_index, p_s0);
+  nat44_ei_session_t *s0 = *p_s0;
+  if (PREDICT_TRUE (next0 != NAT44_EI_OUT2IN_NEXT_DROP && s0))
     {
       /* Accounting */
       nat44_ei_session_update_counters (
 	s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
       /* Per-user LRU list maintenance */
-      nat44_session_update_lru (sm, s0, thread_index);
+      nat44_ei_session_update_lru (nm, s0, thread_index);
     }
   return next0;
 }
 
 static int
-nat_out2in_sm_unknown_proto (snat_main_t * sm,
-			     vlib_buffer_t * b,
-			     ip4_header_t * ip, u32 rx_fib_index)
+nat_out2in_sm_unknown_proto (nat44_ei_main_t *nm, vlib_buffer_t *b,
+			     ip4_header_t *ip, u32 rx_fib_index)
 {
   clib_bihash_kv_8_8_t kv, value;
-  snat_static_mapping_t *m;
+  nat44_ei_static_mapping_t *m;
   u32 old_addr, new_addr;
   ip_csum_t sum;
 
   init_nat_k (&kv, ip->dst_address, 0, 0, 0);
-  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+  if (clib_bihash_search_8_8 (&nm->static_mapping_by_external, &kv, &value))
     return 1;
 
-  m = pool_elt_at_index (sm->static_mappings, value.value);
+  m = pool_elt_at_index (nm->static_mappings, value.value);
 
   old_addr = ip->dst_address.as_u32;
   new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
@@ -708,15 +697,14 @@ nat_out2in_sm_unknown_proto (snat_main_t * sm,
   return 0;
 }
 
-VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
-				 vlib_node_runtime_t * node,
-				 vlib_frame_t * frame)
+VLIB_NODE_FN (nat44_ei_out2in_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
   u32 n_left_from, *from;
-  snat_main_t *sm = &snat_main;
+  nat44_ei_main_t *nm = &nat44_ei_main;
   f64 now = vlib_time_now (vm);
   u32 thread_index = vm->thread_index;
-  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  nat44_ei_main_per_thread_data_t *tnm = &nm->per_thread_data[thread_index];
 
   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
@@ -728,8 +716,8 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
   while (n_left_from >= 2)
     {
       vlib_buffer_t *b0, *b1;
-      u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
-      u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
+      u32 next0 = NAT44_EI_OUT2IN_NEXT_LOOKUP;
+      u32 next1 = NAT44_EI_OUT2IN_NEXT_LOOKUP;
       u32 sw_if_index0, sw_if_index1;
       ip4_header_t *ip0, *ip1;
       ip_csum_t sum0, sum1;
@@ -742,7 +730,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       icmp46_header_t *icmp0, *icmp1;
       u32 rx_fib_index0, rx_fib_index1;
       u32 proto0, proto1;
-      snat_session_t *s0 = 0, *s1 = 0;
+      nat44_ei_session_t *s0 = 0, *s1 = 0;
       clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
       u8 identity_nat0, identity_nat1;
       ip4_address_t sm_addr0, sm_addr1;
@@ -778,8 +766,8 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       icmp0 = (icmp46_header_t *) udp0;
 
       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
-      rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
-			       sw_if_index0);
+      rx_fib_index0 =
+	vec_elt (nm->ip4_main->fib_index_by_sw_if_index, sw_if_index0);
 
       if (PREDICT_FALSE (ip0->ttl == 1))
 	{
@@ -787,7 +775,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	  icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
 				       0);
-	  next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+	  next0 = NAT44_EI_OUT2IN_NEXT_ICMP_ERROR;
 	  goto trace0;
 	}
 
@@ -795,16 +783,16 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 
       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 	{
-	  if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
+	  if (nat_out2in_sm_unknown_proto (nm, b0, ip0, rx_fib_index0))
 	    {
-	      if (!sm->forwarding_enabled)
+	      if (!nm->forwarding_enabled)
 		{
 		  b0->error =
-		    node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
-		  next0 = SNAT_OUT2IN_NEXT_DROP;
+		    node->errors[NAT44_EI_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+		  next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 		}
 	    }
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.other,
 					 thread_index, sw_if_index0, 1);
 
 	  goto trace0;
@@ -812,10 +800,10 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 
       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	{
-	  next0 = icmp_out2in_slow_path
-	    (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-	     next0, now, thread_index, &s0);
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
+	  next0 = nat44_ei_icmp_out2in_slow_path (
+	    nm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node, next0, now,
+	    thread_index, &s0);
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.icmp,
 					 thread_index, sw_if_index0, 1);
 	  goto trace0;
 	}
@@ -823,7 +811,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       init_nat_k (&kv0, ip0->dst_address,
 		  vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 		  proto0);
-      if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
+      if (clib_bihash_search_8_8 (&nm->out2in, &kv0, &value0))
 	{
 	  /* Try to match static mapping by external address and port,
 	     destination address and port in packet */
@@ -845,10 +833,11 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 		  goto trace0;
 		}
 
-	      if (!sm->forwarding_enabled)
+	      if (!nm->forwarding_enabled)
 		{
-		  b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-		  next0 = SNAT_OUT2IN_NEXT_DROP;
+		  b0->error =
+		    node->errors[NAT44_EI_OUT2IN_ERROR_NO_TRANSLATION];
+		  next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 		}
 	      goto trace0;
 	    }
@@ -857,22 +846,18 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	    goto trace0;
 
 	  /* Create session initiated by host from external network */
-	  s0 = create_session_for_static_mapping (sm, b0,
-						  sm_addr0, sm_port0,
-						  sm_fib_index0,
-						  ip0->dst_address,
-						  vnet_buffer (b0)->ip.
-						  reass.l4_dst_port,
-						  rx_fib_index0, proto0, node,
-						  thread_index, now);
+	  s0 = create_session_for_static_mapping (
+	    nm, b0, sm_addr0, sm_port0, sm_fib_index0, ip0->dst_address,
+	    vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0, proto0,
+	    node, thread_index, now);
 	  if (!s0)
 	    {
-	      next0 = SNAT_OUT2IN_NEXT_DROP;
+	      next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 	      goto trace0;
 	    }
 	}
       else
-	s0 = pool_elt_at_index (tsm->sessions,
+	s0 = pool_elt_at_index (tnm->sessions,
 				nat_value_get_session_index (&value0));
 
       old_addr0 = ip0->dst_address.as_u32;
@@ -901,7 +886,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 				     length /* changed member */ );
 	      tcp0->checksum = ip_csum_fold (sum0);
 	    }
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.tcp,
 					 thread_index, sw_if_index0, 1);
 	}
       else
@@ -922,7 +907,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 		  udp0->checksum = ip_csum_fold (sum0);
 		}
 	    }
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.udp,
 					 thread_index, sw_if_index0, 1);
 	}
 
@@ -930,24 +915,24 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       nat44_ei_session_update_counters (
 	s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
       /* Per-user LRU list maintenance */
-      nat44_session_update_lru (sm, s0, thread_index);
+      nat44_ei_session_update_lru (nm, s0, thread_index);
     trace0:
 
       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 			 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 	{
-	  snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+	  nat44_ei_out2in_trace_t *t =
+	    vlib_add_trace (vm, node, b0, sizeof (*t));
 	  t->sw_if_index = sw_if_index0;
 	  t->next_index = next0;
 	  t->session_index = ~0;
 	  if (s0)
-	    t->session_index =
-	      s0 - sm->per_thread_data[thread_index].sessions;
+	    t->session_index = s0 - nm->per_thread_data[thread_index].sessions;
 	}
 
-      if (next0 == SNAT_OUT2IN_NEXT_DROP)
+      if (next0 == NAT44_EI_OUT2IN_NEXT_DROP)
 	{
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.drops,
 					 thread_index, sw_if_index0, 1);
 	}
 
@@ -958,8 +943,8 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       icmp1 = (icmp46_header_t *) udp1;
 
       sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
-      rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
-			       sw_if_index1);
+      rx_fib_index1 =
+	vec_elt (nm->ip4_main->fib_index_by_sw_if_index, sw_if_index1);
 
       if (PREDICT_FALSE (ip1->ttl == 1))
 	{
@@ -967,7 +952,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	  icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
 				       0);
-	  next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+	  next1 = NAT44_EI_OUT2IN_NEXT_ICMP_ERROR;
 	  goto trace1;
 	}
 
@@ -975,26 +960,26 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 
       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
 	{
-	  if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
+	  if (nat_out2in_sm_unknown_proto (nm, b1, ip1, rx_fib_index1))
 	    {
-	      if (!sm->forwarding_enabled)
+	      if (!nm->forwarding_enabled)
 		{
 		  b1->error =
-		    node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
-		  next1 = SNAT_OUT2IN_NEXT_DROP;
+		    node->errors[NAT44_EI_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+		  next1 = NAT44_EI_OUT2IN_NEXT_DROP;
 		}
 	    }
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.other,
 					 thread_index, sw_if_index1, 1);
 	  goto trace1;
 	}
 
       if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 	{
-	  next1 = icmp_out2in_slow_path
-	    (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
-	     next1, now, thread_index, &s1);
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
+	  next1 = nat44_ei_icmp_out2in_slow_path (
+	    nm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node, next1, now,
+	    thread_index, &s1);
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.icmp,
 					 thread_index, sw_if_index1, 1);
 	  goto trace1;
 	}
@@ -1002,7 +987,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       init_nat_k (&kv1, ip1->dst_address,
 		  vnet_buffer (b1)->ip.reass.l4_dst_port, rx_fib_index1,
 		  proto1);
-      if (clib_bihash_search_8_8 (&sm->out2in, &kv1, &value1))
+      if (clib_bihash_search_8_8 (&nm->out2in, &kv1, &value1))
 	{
 	  /* Try to match static mapping by external address and port,
 	     destination address and port in packet */
@@ -1024,10 +1009,11 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 		  goto trace1;
 		}
 
-	      if (!sm->forwarding_enabled)
+	      if (!nm->forwarding_enabled)
 		{
-		  b1->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-		  next1 = SNAT_OUT2IN_NEXT_DROP;
+		  b1->error =
+		    node->errors[NAT44_EI_OUT2IN_ERROR_NO_TRANSLATION];
+		  next1 = NAT44_EI_OUT2IN_NEXT_DROP;
 		}
 	      goto trace1;
 	    }
@@ -1036,22 +1022,18 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	    goto trace1;
 
 	  /* Create session initiated by host from external network */
-	  s1 =
-	    create_session_for_static_mapping (sm, b1, sm_addr1, sm_port1,
-					       sm_fib_index1,
-					       ip1->dst_address,
-					       vnet_buffer (b1)->ip.
-					       reass.l4_dst_port,
-					       rx_fib_index1, proto1, node,
-					       thread_index, now);
+	  s1 = create_session_for_static_mapping (
+	    nm, b1, sm_addr1, sm_port1, sm_fib_index1, ip1->dst_address,
+	    vnet_buffer (b1)->ip.reass.l4_dst_port, rx_fib_index1, proto1,
+	    node, thread_index, now);
 	  if (!s1)
 	    {
-	      next1 = SNAT_OUT2IN_NEXT_DROP;
+	      next1 = NAT44_EI_OUT2IN_NEXT_DROP;
 	      goto trace1;
 	    }
 	}
       else
-	s1 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
+	s1 = pool_elt_at_index (nm->per_thread_data[thread_index].sessions,
 				nat_value_get_session_index (&value1));
 
       old_addr1 = ip1->dst_address.as_u32;
@@ -1081,7 +1063,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 				     length /* changed member */ );
 	      tcp1->checksum = ip_csum_fold (sum1);
 	    }
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.tcp,
 					 thread_index, sw_if_index1, 1);
 	}
       else
@@ -1105,7 +1087,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 		  udp1->checksum = ip_csum_fold (sum1);
 		}
 	    }
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.udp,
 					 thread_index, sw_if_index1, 1);
 	}
 
@@ -1113,24 +1095,24 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       nat44_ei_session_update_counters (
 	s1, now, vlib_buffer_length_in_chain (vm, b1), thread_index);
       /* Per-user LRU list maintenance */
-      nat44_session_update_lru (sm, s1, thread_index);
+      nat44_ei_session_update_lru (nm, s1, thread_index);
     trace1:
 
       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 			 && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 	{
-	  snat_out2in_trace_t *t = vlib_add_trace (vm, node, b1, sizeof (*t));
+	  nat44_ei_out2in_trace_t *t =
+	    vlib_add_trace (vm, node, b1, sizeof (*t));
 	  t->sw_if_index = sw_if_index1;
 	  t->next_index = next1;
 	  t->session_index = ~0;
 	  if (s1)
-	    t->session_index =
-	      s1 - sm->per_thread_data[thread_index].sessions;
+	    t->session_index = s1 - nm->per_thread_data[thread_index].sessions;
 	}
 
-      if (next1 == SNAT_OUT2IN_NEXT_DROP)
+      if (next1 == NAT44_EI_OUT2IN_NEXT_DROP)
 	{
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.drops,
 					 thread_index, sw_if_index1, 1);
 	}
 
@@ -1143,7 +1125,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
   while (n_left_from > 0)
     {
       vlib_buffer_t *b0;
-      u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
+      u32 next0 = NAT44_EI_OUT2IN_NEXT_LOOKUP;
       u32 sw_if_index0;
       ip4_header_t *ip0;
       ip_csum_t sum0;
@@ -1154,7 +1136,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       icmp46_header_t *icmp0;
       u32 rx_fib_index0;
       u32 proto0;
-      snat_session_t *s0 = 0;
+      nat44_ei_session_t *s0 = 0;
       clib_bihash_kv_8_8_t kv0, value0;
       u8 identity_nat0;
       ip4_address_t sm_addr0;
@@ -1172,23 +1154,23 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       icmp0 = (icmp46_header_t *) udp0;
 
       sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
-      rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
-			       sw_if_index0);
+      rx_fib_index0 =
+	vec_elt (nm->ip4_main->fib_index_by_sw_if_index, sw_if_index0);
 
       proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 	{
-	  if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
+	  if (nat_out2in_sm_unknown_proto (nm, b0, ip0, rx_fib_index0))
 	    {
-	      if (!sm->forwarding_enabled)
+	      if (!nm->forwarding_enabled)
 		{
 		  b0->error =
-		    node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
-		  next0 = SNAT_OUT2IN_NEXT_DROP;
+		    node->errors[NAT44_EI_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+		  next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 		}
 	    }
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.other,
 					 thread_index, sw_if_index0, 1);
 	  goto trace00;
 	}
@@ -1199,16 +1181,16 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	  icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
 				       0);
-	  next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+	  next0 = NAT44_EI_OUT2IN_NEXT_ICMP_ERROR;
 	  goto trace00;
 	}
 
       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	{
-	  next0 = icmp_out2in_slow_path
-	    (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-	     next0, now, thread_index, &s0);
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
+	  next0 = nat44_ei_icmp_out2in_slow_path (
+	    nm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node, next0, now,
+	    thread_index, &s0);
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.icmp,
 					 thread_index, sw_if_index0, 1);
 	  goto trace00;
 	}
@@ -1217,7 +1199,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 		  vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 		  proto0);
 
-      if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
+      if (clib_bihash_search_8_8 (&nm->out2in, &kv0, &value0))
 	{
 	  /* Try to match static mapping by external address and port,
 	     destination address and port in packet */
@@ -1239,10 +1221,11 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 		  goto trace00;
 		}
 
-	      if (!sm->forwarding_enabled)
+	      if (!nm->forwarding_enabled)
 		{
-		  b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-		  next0 = SNAT_OUT2IN_NEXT_DROP;
+		  b0->error =
+		    node->errors[NAT44_EI_OUT2IN_ERROR_NO_TRANSLATION];
+		  next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 		}
 	      goto trace00;
 	    }
@@ -1251,22 +1234,18 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	    goto trace00;
 
 	  /* Create session initiated by host from external network */
-	  s0 = create_session_for_static_mapping (sm, b0,
-						  sm_addr0, sm_port0,
-						  sm_fib_index0,
-						  ip0->dst_address,
-						  vnet_buffer (b0)->ip.
-						  reass.l4_dst_port,
-						  rx_fib_index0, proto0, node,
-						  thread_index, now);
+	  s0 = create_session_for_static_mapping (
+	    nm, b0, sm_addr0, sm_port0, sm_fib_index0, ip0->dst_address,
+	    vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0, proto0,
+	    node, thread_index, now);
 	  if (!s0)
 	    {
-	      next0 = SNAT_OUT2IN_NEXT_DROP;
+	      next0 = NAT44_EI_OUT2IN_NEXT_DROP;
 	      goto trace00;
 	    }
 	}
       else
-	s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
+	s0 = pool_elt_at_index (nm->per_thread_data[thread_index].sessions,
 				nat_value_get_session_index (&value0));
 
       old_addr0 = ip0->dst_address.as_u32;
@@ -1296,7 +1275,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 				     length /* changed member */ );
 	      tcp0->checksum = ip_csum_fold (sum0);
 	    }
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.tcp,
 					 thread_index, sw_if_index0, 1);
 	}
       else
@@ -1317,7 +1296,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 		  udp0->checksum = ip_csum_fold (sum0);
 		}
 	    }
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.udp,
 					 thread_index, sw_if_index0, 1);
 	}
 
@@ -1325,24 +1304,24 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       nat44_ei_session_update_counters (
 	s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
       /* Per-user LRU list maintenance */
-      nat44_session_update_lru (sm, s0, thread_index);
+      nat44_ei_session_update_lru (nm, s0, thread_index);
     trace00:
 
       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 			 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 	{
-	  snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+	  nat44_ei_out2in_trace_t *t =
+	    vlib_add_trace (vm, node, b0, sizeof (*t));
 	  t->sw_if_index = sw_if_index0;
 	  t->next_index = next0;
 	  t->session_index = ~0;
 	  if (s0)
-	    t->session_index =
-	      s0 - sm->per_thread_data[thread_index].sessions;
+	    t->session_index = s0 - nm->per_thread_data[thread_index].sessions;
 	}
 
-      if (next0 == SNAT_OUT2IN_NEXT_DROP)
+      if (next0 == NAT44_EI_OUT2IN_NEXT_DROP)
 	{
-	  vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
+	  vlib_increment_simple_counter (&nm->counters.slowpath.out2in.drops,
 					 thread_index, sw_if_index0, 1);
 	}
 
@@ -1358,34 +1337,33 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 }
 
 /* *INDENT-OFF* */
-VLIB_REGISTER_NODE (snat_out2in_node) = {
-  .name = "nat44-out2in",
+VLIB_REGISTER_NODE (nat44_ei_out2in_node) = {
+  .name = "nat44-ei-out2in",
   .vector_size = sizeof (u32),
-  .format_trace = format_snat_out2in_trace,
+  .format_trace = format_nat44_ei_out2in_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
 
-  .n_errors = ARRAY_LEN(snat_out2in_error_strings),
-  .error_strings = snat_out2in_error_strings,
+  .n_errors = ARRAY_LEN(nat44_ei_out2in_error_strings),
+  .error_strings = nat44_ei_out2in_error_strings,
 
-  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
 
-  .n_next_nodes = SNAT_OUT2IN_N_NEXT,
+  .n_next_nodes = NAT44_EI_OUT2IN_N_NEXT,
 
   /* edit / add dispositions here */
   .next_nodes = {
-    [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
-    [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
-    [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT44_EI_OUT2IN_NEXT_DROP] = "error-drop",
+    [NAT44_EI_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT44_EI_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
   },
 };
 /* *INDENT-ON* */
 
-VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
-				      vlib_node_runtime_t * node,
-				      vlib_frame_t * frame)
+VLIB_NODE_FN (nat44_ei_out2in_fast_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
   u32 n_left_from, *from;
-  snat_main_t *sm = &snat_main;
+  nat44_ei_main_t *nm = &nat44_ei_main;
 
   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
@@ -1396,7 +1374,7 @@ VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
   while (n_left_from > 0)
     {
       vlib_buffer_t *b0;
-      u32 next0 = SNAT_OUT2IN_NEXT_DROP;
+      u32 next0 = NAT44_EI_OUT2IN_NEXT_DROP;
       u32 sw_if_index0;
       ip4_header_t *ip0;
       ip_csum_t sum0;
@@ -1430,7 +1408,7 @@ VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
 	  icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
 				       0);
-	  next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+	  next0 = NAT44_EI_OUT2IN_NEXT_ICMP_ERROR;
 	  goto trace00;
 	}
 
@@ -1441,8 +1419,8 @@ VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
 
       if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	{
-	  next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0,
-			       node, next0, ~0, 0);
+	  next0 = nat44_ei_icmp_out2in (b0, ip0, icmp0, sw_if_index0,
+					rx_fib_index0, node, next0, ~0, 0);
 	  goto trace00;
 	}
 
@@ -1450,7 +1428,7 @@ VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
 					 rx_fib_index0, proto0, &sm_addr0,
 					 &sm_port0, &sm_fib_index0, 1, 0, 0))
 	{
-	  b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+	  b0->error = node->errors[NAT44_EI_OUT2IN_ERROR_NO_TRANSLATION];
 	  goto trace00;
 	}
 
@@ -1518,14 +1496,15 @@ VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 			 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 	{
-	  snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+	  nat44_ei_out2in_trace_t *t =
+	    vlib_add_trace (vm, node, b0, sizeof (*t));
 	  t->sw_if_index = sw_if_index0;
 	  t->next_index = next0;
 	}
 
-      if (next0 == SNAT_OUT2IN_NEXT_DROP)
+      if (next0 == NAT44_EI_OUT2IN_NEXT_DROP)
 	{
-	  vlib_increment_simple_counter (&sm->counters.fastpath.out2in.drops,
+	  vlib_increment_simple_counter (&nm->counters.fastpath.out2in.drops,
 					 vm->thread_index, sw_if_index0, 1);
 	}
 
@@ -1541,24 +1520,24 @@ VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
 }
 
 /* *INDENT-OFF* */
-VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
-  .name = "nat44-out2in-fast",
+VLIB_REGISTER_NODE (nat44_ei_out2in_fast_node) = {
+  .name = "nat44-ei-out2in-fast",
   .vector_size = sizeof (u32),
-  .format_trace = format_snat_out2in_fast_trace,
+  .format_trace = format_nat44_ei_out2in_fast_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
 
-  .n_errors = ARRAY_LEN(snat_out2in_error_strings),
-  .error_strings = snat_out2in_error_strings,
+  .n_errors = ARRAY_LEN(nat44_ei_out2in_error_strings),
+  .error_strings = nat44_ei_out2in_error_strings,
 
-  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
 
-  .n_next_nodes = SNAT_OUT2IN_N_NEXT,
+  .n_next_nodes = NAT44_EI_OUT2IN_N_NEXT,
 
   /* edit / add dispositions here */
   .next_nodes = {
-    [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
-    [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
-    [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT44_EI_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT44_EI_OUT2IN_NEXT_DROP] = "error-drop",
+    [NAT44_EI_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
   },
 };
 /* *INDENT-ON* */