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, 585 insertions, 566 deletions

diff --git a/src/plugins/nat/nat44-ei/nat44_ei_in2out.c b/src/plugins/nat/nat44-ei/nat44_ei_in2out.c
index 54ed1a92e8b..80beb7a49eb 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei_in2out.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei_in2out.c
@@ -14,28 +14,27 @@
  */
 /**
  * @file
- * @brief NAT44 inside to outside network translation
+ * @brief NAT44 EI inside to outside network translation
  */
 
 #include <vlib/vlib.h>
-#include <vnet/vnet.h>
 
+#include <vnet/vnet.h>
 #include <vnet/ip/ip.h>
 #include <vnet/ethernet/ethernet.h>
-#include <vnet/fib/ip4_fib.h>
 #include <vnet/udp/udp_local.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 <vnet/fib/ip4_fib.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/lib/nat_inlines.h>
-#include <nat/nat44_hairpinning.h>
+#include <nat/nat44-ei/nat44_ei_inlines.h>
+#include <nat/nat44-ei/nat44_ei.h>
+#include <nat/nat44-ei/nat44_ei_hairpinning.h>
 
 typedef struct
 {
@@ -44,15 +43,15 @@ typedef struct
   u32 session_index;
   u32 is_slow_path;
   u32 is_hairpinning;
-} snat_in2out_trace_t;
+} nat44_ei_in2out_trace_t;
 
 /* packet trace format function */
 static u8 *
-format_snat_in2out_trace (u8 * s, va_list * args)
+format_nat44_ei_in2out_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_in2out_trace_t *t = va_arg (*args, snat_in2out_trace_t *);
+  nat44_ei_in2out_trace_t *t = va_arg (*args, nat44_ei_in2out_trace_t *);
   char *tag;
 
   tag = t->is_slow_path ? "NAT44_IN2OUT_SLOW_PATH" : "NAT44_IN2OUT_FAST_PATH";
@@ -68,11 +67,11 @@ format_snat_in2out_trace (u8 * s, va_list * args)
 }
 
 static u8 *
-format_snat_in2out_fast_trace (u8 * s, va_list * args)
+format_nat44_ei_in2out_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_in2out_trace_t *t = va_arg (*args, snat_in2out_trace_t *);
+  nat44_ei_in2out_trace_t *t = va_arg (*args, nat44_ei_in2out_trace_t *);
 
   s = format (s, "NAT44_IN2OUT_FAST: sw_if_index %d, next index %d",
 	      t->sw_if_index, t->next_index);
@@ -80,67 +79,125 @@ format_snat_in2out_fast_trace (u8 * s, va_list * args)
   return s;
 }
 
-#define foreach_snat_in2out_error                       \
-_(UNSUPPORTED_PROTOCOL, "unsupported protocol")         \
-_(OUT_OF_PORTS, "out of ports")                         \
-_(BAD_OUTSIDE_FIB, "outside VRF ID not found")          \
-_(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_in2out_error                                         \
+  _ (UNSUPPORTED_PROTOCOL, "unsupported protocol")                            \
+  _ (OUT_OF_PORTS, "out of ports")                                            \
+  _ (BAD_OUTSIDE_FIB, "outside VRF ID not found")                             \
+  _ (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_IN2OUT_ERROR_##sym,
-  foreach_snat_in2out_error
+#define _(sym, str) NAT44_EI_IN2OUT_ERROR_##sym,
+  foreach_nat44_ei_in2out_error
 #undef _
-    SNAT_IN2OUT_N_ERROR,
-} snat_in2out_error_t;
+    NAT44_EI_IN2OUT_N_ERROR,
+} nat44_ei_in2out_error_t;
 
-static char *snat_in2out_error_strings[] = {
+static char *nat44_ei_in2out_error_strings[] = {
 #define _(sym,string) string,
-  foreach_snat_in2out_error
+  foreach_nat44_ei_in2out_error
 #undef _
 };
 
 typedef enum
 {
-  SNAT_IN2OUT_NEXT_LOOKUP,
-  SNAT_IN2OUT_NEXT_DROP,
-  SNAT_IN2OUT_NEXT_ICMP_ERROR,
-  SNAT_IN2OUT_NEXT_SLOW_PATH,
-  SNAT_IN2OUT_NEXT_HAIRPINNING_HANDOFF,
-  SNAT_IN2OUT_N_NEXT,
-} snat_in2out_next_t;
+  NAT44_EI_IN2OUT_NEXT_LOOKUP,
+  NAT44_EI_IN2OUT_NEXT_DROP,
+  NAT44_EI_IN2OUT_NEXT_ICMP_ERROR,
+  NAT44_EI_IN2OUT_NEXT_SLOW_PATH,
+  NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF,
+  NAT44_EI_IN2OUT_N_NEXT,
+} nat44_ei_in2out_next_t;
 
 typedef enum
 {
-  NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP,
-  NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP,
-  NAT44_IN2OUT_HAIRPINNING_FINISH_N_NEXT,
-} nat44_in2out_hairpinnig_finish_next_t;
+  NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP,
+  NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP,
+  NAT44_EI_IN2OUT_HAIRPINNING_FINISH_N_NEXT,
+} nat44_ei_in2out_hairpinnig_finish_next_t;
+
+static inline int
+nat44_ei_not_translate_fast (vlib_node_runtime_t *node, u32 sw_if_index0,
+			     ip4_header_t *ip0, u32 proto0, u32 rx_fib_index0)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+
+  if (nm->out2in_dpo)
+    return 0;
+
+  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
+  nat44_ei_outside_fib_t *outside_fib;
+  fib_prefix_t pfx = {
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_len = 32,
+    .fp_addr = {
+		.ip4.as_u32 = ip0->dst_address.as_u32,
+		}
+    ,
+  };
+
+  /* Don't NAT packet aimed at the intfc address */
+  if (PREDICT_FALSE (nat44_ei_is_interface_addr (
+	nm->ip4_main, node, sw_if_index0, ip0->dst_address.as_u32)))
+    return 1;
+
+  fei = fib_table_lookup (rx_fib_index0, &pfx);
+  if (FIB_NODE_INDEX_INVALID != fei)
+    {
+      u32 sw_if_index = fib_entry_get_resolving_interface (fei);
+      if (sw_if_index == ~0)
+	{
+	  vec_foreach (outside_fib, nm->outside_fibs)
+	    {
+	      fei = fib_table_lookup (outside_fib->fib_index, &pfx);
+	      if (FIB_NODE_INDEX_INVALID != fei)
+		{
+		  sw_if_index = fib_entry_get_resolving_interface (fei);
+		  if (sw_if_index != ~0)
+		    break;
+		}
+	    }
+	}
+      if (sw_if_index == ~0)
+	return 1;
+
+      nat44_ei_interface_t *i;
+      pool_foreach (i, nm->interfaces)
+	{
+	  /* NAT packet aimed at outside interface */
+	  if ((nat44_ei_interface_is_outside (i)) &&
+	      (sw_if_index == i->sw_if_index))
+	    return 0;
+	}
+    }
+
+  return 1;
+}
 
 static inline int
-snat_not_translate (snat_main_t * sm, vlib_node_runtime_t * node,
-		    u32 sw_if_index0, ip4_header_t * ip0, u32 proto0,
-		    u32 rx_fib_index0, u32 thread_index)
+nat44_ei_not_translate (nat44_ei_main_t *nm, vlib_node_runtime_t *node,
+			u32 sw_if_index0, ip4_header_t *ip0, u32 proto0,
+			u32 rx_fib_index0, u32 thread_index)
 {
   udp_header_t *udp0 = ip4_next_header (ip0);
   clib_bihash_kv_8_8_t kv0, value0;
 
-  init_nat_k (&kv0, ip0->dst_address, udp0->dst_port, sm->outside_fib_index,
+  init_nat_k (&kv0, ip0->dst_address, udp0->dst_port, nm->outside_fib_index,
 	      proto0);
 
   /* NAT packet aimed at external address if */
   /* has active sessions */
-  if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
+  if (clib_bihash_search_8_8 (&nm->out2in, &kv0, &value0))
     {
       /* or is static mappings */
       ip4_address_t placeholder_addr;
       u16 placeholder_port;
       u32 placeholder_fib_index;
       if (!nat44_ei_static_mapping_match (ip0->dst_address, udp0->dst_port,
-					  sm->outside_fib_index, proto0,
+					  nm->outside_fib_index, proto0,
 					  &placeholder_addr, &placeholder_port,
 					  &placeholder_fib_index, 1, 0, 0))
 	return 0;
@@ -148,37 +205,38 @@ snat_not_translate (snat_main_t * sm, vlib_node_runtime_t * node,
   else
     return 0;
 
-  if (sm->forwarding_enabled)
+  if (nm->forwarding_enabled)
     return 1;
 
-  return snat_not_translate_fast (sm, node, sw_if_index0, ip0, proto0,
-				  rx_fib_index0);
+  return nat44_ei_not_translate_fast (node, sw_if_index0, ip0, proto0,
+				      rx_fib_index0);
 }
 
 static inline int
-nat_not_translate_output_feature (snat_main_t * sm, ip4_header_t * ip0,
-				  u32 proto0, u16 src_port, u16 dst_port,
-				  u32 thread_index, u32 sw_if_index)
+nat44_ei_not_translate_output_feature (nat44_ei_main_t *nm, ip4_header_t *ip0,
+				       u32 proto0, u16 src_port, u16 dst_port,
+				       u32 thread_index, u32 sw_if_index)
 {
   clib_bihash_kv_8_8_t kv0, value0;
-  snat_interface_t *i;
+  nat44_ei_interface_t *i;
 
   /* src NAT check */
   init_nat_k (&kv0, ip0->src_address, src_port,
 	      ip4_fib_table_get_index_for_sw_if_index (sw_if_index), proto0);
 
-  if (!clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
+  if (!clib_bihash_search_8_8 (&nm->out2in, &kv0, &value0))
     return 1;
 
   /* dst NAT check */
   init_nat_k (&kv0, ip0->dst_address, dst_port,
 	      ip4_fib_table_get_index_for_sw_if_index (sw_if_index), proto0);
-  if (!clib_bihash_search_8_8 (&sm->in2out, &kv0, &value0))
+  if (!clib_bihash_search_8_8 (&nm->in2out, &kv0, &value0))
     {
       /* hairpinning */
-      pool_foreach (i, sm->output_feature_interfaces)
+      pool_foreach (i, nm->output_feature_interfaces)
 	{
-	  if ((nat_interface_is_inside (i)) && (sw_if_index == i->sw_if_index))
+	  if ((nat44_ei_interface_is_inside (i)) &&
+	      (sw_if_index == i->sw_if_index))
 	    return 0;
 	}
       return 1;
@@ -191,21 +249,22 @@ nat_not_translate_output_feature (snat_main_t * sm, ip4_header_t * ip0,
 int
 nat44_i2o_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_o2i_k (&s_kv, s);
-      if (clib_bihash_add_del_8_8 (&sm->out2in, &s_kv, 0))
-	nat_elog_warn ("out2in key del failed");
+      if (clib_bihash_add_del_8_8 (&nm->out2in, &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,
@@ -223,12 +282,12 @@ nat44_i2o_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;
     }
 
@@ -237,20 +296,16 @@ nat44_i2o_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 #endif
 
 static u32
-slow_path (snat_main_t * sm, vlib_buffer_t * b0,
-	   ip4_header_t * ip0,
-	   ip4_address_t i2o_addr,
-	   u16 i2o_port,
-	   u32 rx_fib_index0,
-	   nat_protocol_t nat_proto,
-	   snat_session_t ** sessionp,
-	   vlib_node_runtime_t * node, u32 next0, u32 thread_index, f64 now)
+slow_path (nat44_ei_main_t *nm, vlib_buffer_t *b0, ip4_header_t *ip0,
+	   ip4_address_t i2o_addr, u16 i2o_port, u32 rx_fib_index0,
+	   nat_protocol_t nat_proto, nat44_ei_session_t **sessionp,
+	   vlib_node_runtime_t *node, u32 next0, u32 thread_index, f64 now)
 {
-  snat_user_t *u;
-  snat_session_t *s = 0;
+  nat44_ei_user_t *u;
+  nat44_ei_session_t *s = 0;
   clib_bihash_kv_8_8_t kv0;
   u8 is_sm = 0;
-  nat_outside_fib_t *outside_fib;
+  nat44_ei_outside_fib_t *outside_fib;
   fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
   u8 identity_nat;
   fib_prefix_t pfx = {
@@ -260,18 +315,18 @@ slow_path (snat_main_t * sm, vlib_buffer_t * b0,
 		.ip4.as_u32 = ip0->dst_address.as_u32,
 		},
   };
-  nat44_is_idle_session_ctx_t ctx0;
+  nat44_ei_is_idle_session_ctx_t ctx0;
   ip4_address_t sm_addr;
   u16 sm_port;
   u32 sm_fib_index;
 
-  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_IN2OUT_ERROR_MAX_SESSIONS_EXCEEDED];
+      b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_MAX_SESSIONS_EXCEEDED];
       nat_ipfix_logging_max_sessions (thread_index,
-				      sm->max_translations_per_thread);
-      nat_elog_notice ("maximum sessions exceeded");
-      return SNAT_IN2OUT_NEXT_DROP;
+				      nm->max_translations_per_thread);
+      nat_elog_notice (nm, "maximum sessions exceeded");
+      return NAT44_EI_IN2OUT_NEXT_DROP;
     }
 
   /* First try to match static mapping by local address and port */
@@ -280,13 +335,13 @@ slow_path (snat_main_t * sm, vlib_buffer_t * b0,
 				     &sm_fib_index, 0, 0, &identity_nat))
     {
       /* Try to create dynamic translation */
-      if (sm->alloc_addr_and_port (
-	    sm->addresses, rx_fib_index0, thread_index, nat_proto, &sm_addr,
-	    &sm_port, sm->port_per_thread,
-	    sm->per_thread_data[thread_index].snat_thread_index))
+      if (nm->alloc_addr_and_port (
+	    nm->addresses, rx_fib_index0, thread_index, nat_proto, &sm_addr,
+	    &sm_port, nm->port_per_thread,
+	    nm->per_thread_data[thread_index].snat_thread_index))
 	{
-	  b0->error = node->errors[SNAT_IN2OUT_ERROR_OUT_OF_PORTS];
-	  return SNAT_IN2OUT_NEXT_DROP;
+	  b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_OUT_OF_PORTS];
+	  return NAT44_EI_IN2OUT_NEXT_DROP;
 	}
     }
   else
@@ -300,53 +355,53 @@ slow_path (snat_main_t * sm, vlib_buffer_t * b0,
       is_sm = 1;
     }
 
-  u = nat_user_get_or_create (sm, &ip0->src_address, rx_fib_index0,
-			      thread_index);
+  u = nat44_ei_user_get_or_create (nm, &ip0->src_address, rx_fib_index0,
+				   thread_index);
   if (!u)
     {
-      b0->error = node->errors[SNAT_IN2OUT_ERROR_CANNOT_CREATE_USER];
-      return SNAT_IN2OUT_NEXT_DROP;
+      b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_CANNOT_CREATE_USER];
+      return NAT44_EI_IN2OUT_NEXT_DROP;
     }
 
-  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");
-      return SNAT_IN2OUT_NEXT_DROP;
+      nat44_ei_delete_user_with_no_session (nm, u, thread_index);
+      nat_elog_warn (nm, "create NAT session failed");
+      return NAT44_EI_IN2OUT_NEXT_DROP;
     }
 
   if (is_sm)
-    s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
-  user_session_increment (sm, u, is_sm);
+    s->flags |= NAT44_EI_SESSION_FLAG_STATIC_MAPPING;
+  nat44_ei_user_session_increment (nm, u, is_sm);
   s->in2out.addr = i2o_addr;
   s->in2out.port = i2o_port;
   s->in2out.fib_index = rx_fib_index0;
   s->nat_proto = nat_proto;
   s->out2in.addr = sm_addr;
   s->out2in.port = sm_port;
-  s->out2in.fib_index = sm->outside_fib_index;
-  switch (vec_len (sm->outside_fibs))
+  s->out2in.fib_index = nm->outside_fib_index;
+  switch (vec_len (nm->outside_fibs))
     {
     case 0:
-      s->out2in.fib_index = sm->outside_fib_index;
+      s->out2in.fib_index = nm->outside_fib_index;
       break;
     case 1:
-      s->out2in.fib_index = sm->outside_fibs[0].fib_index;
+      s->out2in.fib_index = nm->outside_fibs[0].fib_index;
       break;
     default:
-      vec_foreach (outside_fib, sm->outside_fibs)
-        {
-          fei = fib_table_lookup (outside_fib->fib_index, &pfx);
-          if (FIB_NODE_INDEX_INVALID != fei)
-            {
-              if (fib_entry_get_resolving_interface (fei) != ~0)
-                {
-                  s->out2in.fib_index = outside_fib->fib_index;
-                  break;
-                }
-            }
-        }
+      vec_foreach (outside_fib, nm->outside_fibs)
+	{
+	  fei = fib_table_lookup (outside_fib->fib_index, &pfx);
+	  if (FIB_NODE_INDEX_INVALID != fei)
+	    {
+	      if (fib_entry_get_resolving_interface (fei) != ~0)
+		{
+		  s->out2in.fib_index = outside_fib->fib_index;
+		  break;
+		}
+	    }
+	}
       break;
     }
   s->ext_host_addr.as_u32 = ip0->dst_address.as_u32;
@@ -357,41 +412,38 @@ slow_path (snat_main_t * sm, vlib_buffer_t * b0,
   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,
-				      s->in2out.addr.as_u32,
-				      s->out2in.addr.as_u32,
-				      s->nat_proto,
-				      s->in2out.port,
-				      s->out2in.port, s->in2out.fib_index);
+  nat_ipfix_logging_nat44_ses_create (
+    thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32, s->nat_proto,
+    s->in2out.port, s->out2in.port, s->in2out.fib_index);
 
-  nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index,
-			   &s->in2out.addr, s->in2out.port, &s->out2in.addr,
-			   s->out2in.port, s->nat_proto);
+  nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index, &s->in2out.addr,
+			   s->in2out.port, &s->out2in.addr, s->out2in.port,
+			   s->nat_proto);
 
   nat_ha_sadd (&s->in2out.addr, s->in2out.port, &s->out2in.addr,
 	       s->out2in.port, &s->ext_host_addr, s->ext_host_port,
-	       &s->ext_host_nat_addr, s->ext_host_nat_port,
-	       s->nat_proto, s->in2out.fib_index, s->flags, thread_index, 0);
+	       &s->ext_host_nat_addr, s->ext_host_nat_port, s->nat_proto,
+	       s->in2out.fib_index, s->flags, thread_index, 0);
 
   return next0;
 }
 
 #ifndef CLIB_MARCH_VARIANT
-static_always_inline snat_in2out_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_in2out_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;
@@ -427,7 +479,7 @@ icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
 	  *port = ((tcp_udp_header_t *) l4_header)->dst_port;
 	  break;
 	default:
-	  return SNAT_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL;
+	  return NAT44_EI_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL;
 	}
     }
   return -1;			/* success */
@@ -437,7 +489,7 @@ 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
@@ -449,15 +501,16 @@ icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
  * @param e                      optional parameter
  */
 u32
-icmp_match_in2out_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_in2out_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;
   u32 next0 = ~0;
   int err;
@@ -471,18 +524,17 @@ icmp_match_in2out_slow (snat_main_t *sm, vlib_node_runtime_t *node,
   if (err != -1)
     {
       b0->error = node->errors[err];
-      next0 = SNAT_IN2OUT_NEXT_DROP;
+      next0 = NAT44_EI_IN2OUT_NEXT_DROP;
       goto out;
     }
 
   init_nat_k (&kv0, *addr, *port, *fib_index, *proto);
-  if (clib_bihash_search_8_8 (&sm->in2out, &kv0, &value0))
+  if (clib_bihash_search_8_8 (&nm->in2out, &kv0, &value0))
     {
       if (vnet_buffer (b0)->sw_if_index[VLIB_TX] != ~0)
 	{
-	  if (PREDICT_FALSE
-	      (nat_not_translate_output_feature
-	       (sm, ip0, *proto, *port, *port, thread_index, sw_if_index0)))
+	  if (PREDICT_FALSE (nat44_ei_not_translate_output_feature (
+		nm, ip0, *proto, *port, *port, thread_index, sw_if_index0)))
 	    {
 	      *dont_translate = 1;
 	      goto out;
@@ -490,9 +542,9 @@ icmp_match_in2out_slow (snat_main_t *sm, vlib_node_runtime_t *node,
 	}
       else
 	{
-	  if (PREDICT_FALSE (snat_not_translate (sm, node, sw_if_index0,
-						 ip0, NAT_PROTOCOL_ICMP,
-						 *fib_index, thread_index)))
+	  if (PREDICT_FALSE (nat44_ei_not_translate (
+		nm, node, sw_if_index0, ip0, NAT_PROTOCOL_ICMP, *fib_index,
+		thread_index)))
 	    {
 	      *dont_translate = 1;
 	      goto out;
@@ -503,16 +555,15 @@ icmp_match_in2out_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_IN2OUT_ERROR_BAD_ICMP_TYPE];
-	  next0 = SNAT_IN2OUT_NEXT_DROP;
+	  b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_BAD_ICMP_TYPE];
+	  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
 	  goto out;
 	}
 
-      next0 =
-	slow_path (sm, b0, ip0, *addr, *port, *fib_index, *proto, &s0, node,
-		   next0, thread_index, vlib_time_now (vm));
+      next0 = slow_path (nm, b0, ip0, *addr, *port, *fib_index, *proto, &s0,
+			 node, next0, thread_index, vlib_time_now (vm));
 
-      if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
+      if (PREDICT_FALSE (next0 == NAT44_EI_IN2OUT_NEXT_DROP))
 	goto out;
 
       if (!s0)
@@ -531,12 +582,12 @@ icmp_match_in2out_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_IN2OUT_ERROR_BAD_ICMP_TYPE];
-	  next0 = SNAT_IN2OUT_NEXT_DROP;
+	  b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_BAD_ICMP_TYPE];
+	  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
 	  goto out;
 	}
 
-      s0 = pool_elt_at_index (tsm->sessions,
+      s0 = pool_elt_at_index (tnm->sessions,
 			      nat_value_get_session_index (&value0));
     }
 
@@ -554,26 +605,12 @@ 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_in2out_fast (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 **s0,
-			u8 *dont_translate)
+nat44_ei_icmp_match_in2out_fast (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 **s0, u8 *dont_translate)
 {
   u32 sw_if_index0;
   u8 is_addr_only;
@@ -588,7 +625,7 @@ icmp_match_in2out_fast (snat_main_t *sm, vlib_node_runtime_t *node,
   if (err != -1)
     {
       b0->error = node->errors[err];
-      next0 = SNAT_IN2OUT_NEXT_DROP;
+      next0 = NAT44_EI_IN2OUT_NEXT_DROP;
       goto out;
     }
 
@@ -600,9 +637,8 @@ icmp_match_in2out_fast (snat_main_t *sm, vlib_node_runtime_t *node,
 				     &sm_addr, &sm_port, &sm_fib_index, 0,
 				     &is_addr_only, 0))
     {
-      if (PREDICT_FALSE (snat_not_translate_fast (sm, node, sw_if_index0, ip0,
-						  IP_PROTOCOL_ICMP,
-						  *fib_index)))
+      if (PREDICT_FALSE (nat44_ei_not_translate_fast (
+	    node, sw_if_index0, ip0, IP_PROTOCOL_ICMP, *fib_index)))
 	{
 	  *dont_translate = 1;
 	  goto out;
@@ -611,12 +647,12 @@ icmp_match_in2out_fast (snat_main_t *sm, vlib_node_runtime_t *node,
       if (icmp_type_is_error_message
 	  (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
 	{
-	  next0 = SNAT_IN2OUT_NEXT_DROP;
+	  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
 	  goto out;
 	}
 
-      b0->error = node->errors[SNAT_IN2OUT_ERROR_NO_TRANSLATION];
-      next0 = SNAT_IN2OUT_NEXT_DROP;
+      b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_NO_TRANSLATION];
+      next0 = NAT44_EI_IN2OUT_NEXT_DROP;
       goto out;
     }
 
@@ -627,8 +663,8 @@ icmp_match_in2out_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_IN2OUT_ERROR_BAD_ICMP_TYPE];
-      next0 = SNAT_IN2OUT_NEXT_DROP;
+      b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_BAD_ICMP_TYPE];
+      next0 = NAT44_EI_IN2OUT_NEXT_DROP;
       goto out;
     }
 
@@ -637,23 +673,25 @@ out:
 }
 #endif
 
-u32 icmp_in2out (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_in2out (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_in2out (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_in2out (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;
   vlib_main_t *vm = vlib_get_main ();
   ip4_address_t addr;
   u16 port;
   u32 fib_index;
-  nat_protocol_t protocol;
+  nat_protocol_t proto;
   icmp_echo_header_t *echo0, *inner_echo0 = 0;
   ip4_header_t *inner_ip0;
   void *l4_header = 0;
@@ -669,12 +707,22 @@ icmp_in2out (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
 
   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 
-  next0_tmp =
-    sm->icmp_match_in2out_cb (sm, node, thread_index, b0, ip0, &addr, &port,
-			      &fib_index, &protocol, p_s0, &dont_translate);
+  if (PREDICT_TRUE (nm->pat))
+    {
+      next0_tmp = nat44_ei_icmp_match_in2out_slow (
+	node, thread_index, b0, ip0, &addr, &port, &fib_index, &proto, p_s0,
+	&dont_translate);
+    }
+  else
+    {
+      next0_tmp = nat44_ei_icmp_match_in2out_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_IN2OUT_NEXT_DROP || dont_translate)
+  if (next0 == NAT44_EI_IN2OUT_NEXT_DROP || dont_translate)
     goto out;
 
   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
@@ -688,7 +736,7 @@ icmp_in2out (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
       checksum0 = ~ip_csum_fold (sum0);
       if (PREDICT_FALSE (checksum0 != 0 && checksum0 != 0xffff))
 	{
-	  next0 = SNAT_IN2OUT_NEXT_DROP;
+	  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
 	  goto out;
 	}
     }
@@ -729,7 +777,7 @@ icmp_in2out (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
 
 	  if (!ip4_header_checksum_is_valid (inner_ip0))
 	    {
-	      next0 = SNAT_IN2OUT_NEXT_DROP;
+	      next0 = NAT44_EI_IN2OUT_NEXT_DROP;
 	      goto out;
 	    }
 
@@ -755,7 +803,7 @@ icmp_in2out (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
 			    checksum);
 	  icmp0->checksum = ip_csum_fold (sum0);
 
-	  switch (protocol)
+	  switch (proto)
 	    {
 	    case NAT_PROTOCOL_ICMP:
 	      inner_icmp0 = (icmp46_header_t *) l4_header;
@@ -790,13 +838,13 @@ icmp_in2out (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
 
   if (vnet_buffer (b0)->sw_if_index[VLIB_TX] == ~0)
     {
-      if (0 != snat_icmp_hairpinning (sm, b0, thread_index, ip0, icmp0,
-				      &required_thread_index))
+      if (0 != nat44_ei_icmp_hairpinning (nm, b0, thread_index, ip0, icmp0,
+					  &required_thread_index))
 	vnet_buffer (b0)->sw_if_index[VLIB_TX] = fib_index;
       if (thread_index != required_thread_index)
 	{
 	  vnet_buffer (b0)->snat.required_thread_index = required_thread_index;
-	  next0 = SNAT_IN2OUT_NEXT_HAIRPINNING_HANDOFF;
+	  next0 = NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF;
 	}
     }
 
@@ -805,48 +853,43 @@ out:
 }
 #endif
 
-static inline u32
-icmp_in2out_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)
+static_always_inline u32
+nat44_ei_icmp_in2out_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_in2out (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_IN2OUT_NEXT_DROP && s0))
+  next0 = nat44_ei_icmp_in2out (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_IN2OUT_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_in2out_sm_unknown_proto (snat_main_t * sm,
-			     vlib_buffer_t * b,
-			     ip4_header_t * ip, u32 rx_fib_index)
+nat_in2out_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->src_address, 0, rx_fib_index, 0);
-  if (clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv, &value))
+  if (clib_bihash_search_8_8 (&nm->static_mapping_by_local, &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->src_address.as_u32;
   new_addr = ip->src_address.as_u32 = m->external_addr.as_u32;
@@ -859,20 +902,19 @@ nat_in2out_sm_unknown_proto (snat_main_t * sm,
   if (vnet_buffer (b)->sw_if_index[VLIB_TX] == ~0)
     {
       vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
-      nat_hairpinning_sm_unknown_proto (sm, b, ip);
+      nat44_ei_hairpinning_sm_unknown_proto (nm, b, ip);
     }
 
   return 0;
 }
 
 static inline uword
-snat_in2out_node_fn_inline (vlib_main_t * vm,
-			    vlib_node_runtime_t * node,
-			    vlib_frame_t * frame, int is_slow_path,
-			    int is_output_feature)
+nat44_ei_in2out_node_fn_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
+				vlib_frame_t *frame, int is_slow_path,
+				int is_output_feature)
 {
   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;
 
@@ -897,7 +939,7 @@ snat_in2out_node_fn_inline (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, value0, kv1, value1;
       u32 iph_offset0 = 0, iph_offset1 = 0;
 
@@ -932,10 +974,10 @@ snat_in2out_node_fn_inline (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);
 
-      next0 = next1 = SNAT_IN2OUT_NEXT_LOOKUP;
+      next0 = next1 = NAT44_EI_IN2OUT_NEXT_LOOKUP;
 
       if (PREDICT_FALSE (ip0->ttl == 1))
 	{
@@ -943,7 +985,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	  icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
 				       0);
-	  next0 = SNAT_IN2OUT_NEXT_ICMP_ERROR;
+	  next0 = NAT44_EI_IN2OUT_NEXT_ICMP_ERROR;
 	  goto trace00;
 	}
 
@@ -954,30 +996,28 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	{
 	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 	    {
-	      if (nat_in2out_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
+	      if (nat_in2out_sm_unknown_proto (nm, b0, ip0, rx_fib_index0))
 		{
-		  next0 = SNAT_IN2OUT_NEXT_DROP;
+		  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
 		  b0->error =
-		    node->errors[SNAT_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
+		    node->errors[NAT44_EI_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
 		}
-	      vlib_increment_simple_counter (is_slow_path ? &sm->
-					     counters.slowpath.in2out.
-					     other : &sm->counters.fastpath.
-					     in2out.other, thread_index,
-					     sw_if_index0, 1);
+	      vlib_increment_simple_counter (
+		is_slow_path ? &nm->counters.slowpath.in2out.other :
+			       &nm->counters.fastpath.in2out.other,
+		thread_index, sw_if_index0, 1);
 	      goto trace00;
 	    }
 
 	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	    {
-	      next0 = icmp_in2out_slow_path
-		(sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0,
-		 node, next0, now, thread_index, &s0);
-	      vlib_increment_simple_counter (is_slow_path ? &sm->
-					     counters.slowpath.in2out.
-					     icmp : &sm->counters.fastpath.
-					     in2out.icmp, thread_index,
-					     sw_if_index0, 1);
+	      next0 = nat44_ei_icmp_in2out_slow_path (
+		nm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node, next0,
+		now, thread_index, &s0);
+	      vlib_increment_simple_counter (
+		is_slow_path ? &nm->counters.slowpath.in2out.icmp :
+			       &nm->counters.fastpath.in2out.icmp,
+		thread_index, sw_if_index0, 1);
 	      goto trace00;
 	    }
 	}
@@ -985,13 +1025,13 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	{
 	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 	    {
-	      next0 = SNAT_IN2OUT_NEXT_SLOW_PATH;
+	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
 	      goto trace00;
 	    }
 
 	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	    {
-	      next0 = SNAT_IN2OUT_NEXT_SLOW_PATH;
+	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
 	      goto trace00;
 	    }
 	}
@@ -999,19 +1039,18 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
       init_nat_k (&kv0, ip0->src_address,
 		  vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
 		  proto0);
-      if (PREDICT_FALSE (clib_bihash_search_8_8 (&sm->in2out, &kv0, &value0) !=
+      if (PREDICT_FALSE (clib_bihash_search_8_8 (&nm->in2out, &kv0, &value0) !=
 			 0))
 	{
 	  if (is_slow_path)
 	    {
 	      if (is_output_feature)
 		{
-		  if (PREDICT_FALSE
-		      (nat_not_translate_output_feature
-		       (sm, ip0, proto0,
+		  if (PREDICT_FALSE (nat44_ei_not_translate_output_feature (
+			nm, ip0, proto0,
 			vnet_buffer (b0)->ip.reass.l4_src_port,
-			vnet_buffer (b0)->ip.reass.l4_dst_port,
-			thread_index, sw_if_index0)))
+			vnet_buffer (b0)->ip.reass.l4_dst_port, thread_index,
+			sw_if_index0)))
 		    goto trace00;
 
 		  /*
@@ -1028,19 +1067,17 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		}
 	      else
 		{
-		  if (PREDICT_FALSE
-		      (snat_not_translate
-		       (sm, node, sw_if_index0, ip0, proto0,
-			rx_fib_index0, thread_index)))
+		  if (PREDICT_FALSE (nat44_ei_not_translate (
+			nm, node, sw_if_index0, ip0, proto0, rx_fib_index0,
+			thread_index)))
 		    goto trace00;
 		}
 
-	      next0 = slow_path (sm, b0, ip0,
-				 ip0->src_address,
+	      next0 = slow_path (nm, b0, ip0, ip0->src_address,
 				 vnet_buffer (b0)->ip.reass.l4_src_port,
-				 rx_fib_index0,
-				 proto0, &s0, node, next0, thread_index, now);
-	      if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
+				 rx_fib_index0, proto0, &s0, node, next0,
+				 thread_index, now);
+	      if (PREDICT_FALSE (next0 == NAT44_EI_IN2OUT_NEXT_DROP))
 		goto trace00;
 
 	      if (PREDICT_FALSE (!s0))
@@ -1048,12 +1085,12 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	    }
 	  else
 	    {
-	      next0 = SNAT_IN2OUT_NEXT_SLOW_PATH;
+	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
 	      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));
 
       b0->flags |= VNET_BUFFER_F_IS_NATED;
@@ -1083,12 +1120,12 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	      sum0 = ip_csum_update (sum0, old_port0, new_port0,
 				     ip4_header_t /* cheat */ ,
 				     length /* changed member */ );
-	      mss_clamping (sm->mss_clamping, tcp0, &sum0);
+	      mss_clamping (nm->mss_clamping, tcp0, &sum0);
 	      tcp0->checksum = ip_csum_fold (sum0);
 	    }
-	  vlib_increment_simple_counter (is_slow_path ? &sm->
-					 counters.slowpath.in2out.tcp : &sm->
-					 counters.fastpath.in2out.tcp,
+	  vlib_increment_simple_counter (is_slow_path ?
+					   &nm->counters.slowpath.in2out.tcp :
+					   &nm->counters.fastpath.in2out.tcp,
 					 thread_index, sw_if_index0, 1);
 	}
       else
@@ -1110,9 +1147,9 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		  udp0->checksum = ip_csum_fold (sum0);
 		}
 	    }
-	  vlib_increment_simple_counter (is_slow_path ? &sm->
-					 counters.slowpath.in2out.udp : &sm->
-					 counters.fastpath.in2out.udp,
+	  vlib_increment_simple_counter (is_slow_path ?
+					   &nm->counters.slowpath.in2out.udp :
+					   &nm->counters.fastpath.in2out.udp,
 					 thread_index, sw_if_index0, 1);
 	}
 
@@ -1120,29 +1157,28 @@ snat_in2out_node_fn_inline (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_in2out_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+	  nat44_ei_in2out_trace_t *t =
+	    vlib_add_trace (vm, node, b0, sizeof (*t));
 	  t->is_slow_path = is_slow_path;
 	  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_IN2OUT_NEXT_DROP)
+      if (next0 == NAT44_EI_IN2OUT_NEXT_DROP)
 	{
-	  vlib_increment_simple_counter (is_slow_path ? &sm->
-					 counters.slowpath.in2out.
-					 drops : &sm->counters.fastpath.
-					 in2out.drops, thread_index,
-					 sw_if_index0, 1);
+	  vlib_increment_simple_counter (
+	    is_slow_path ? &nm->counters.slowpath.in2out.drops :
+			   &nm->counters.fastpath.in2out.drops,
+	    thread_index, sw_if_index0, 1);
 	}
 
       if (is_output_feature)
@@ -1156,8 +1192,8 @@ snat_in2out_node_fn_inline (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))
 	{
@@ -1165,7 +1201,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	  icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
 				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
 				       0);
-	  next1 = SNAT_IN2OUT_NEXT_ICMP_ERROR;
+	  next1 = NAT44_EI_IN2OUT_NEXT_ICMP_ERROR;
 	  goto trace01;
 	}
 
@@ -1176,30 +1212,28 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	{
 	  if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
 	    {
-	      if (nat_in2out_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
+	      if (nat_in2out_sm_unknown_proto (nm, b1, ip1, rx_fib_index1))
 		{
-		  next1 = SNAT_IN2OUT_NEXT_DROP;
+		  next1 = NAT44_EI_IN2OUT_NEXT_DROP;
 		  b1->error =
-		    node->errors[SNAT_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
+		    node->errors[NAT44_EI_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
 		}
-	      vlib_increment_simple_counter (is_slow_path ? &sm->
-					     counters.slowpath.in2out.
-					     other : &sm->counters.fastpath.
-					     in2out.other, thread_index,
-					     sw_if_index1, 1);
+	      vlib_increment_simple_counter (
+		is_slow_path ? &nm->counters.slowpath.in2out.other :
+			       &nm->counters.fastpath.in2out.other,
+		thread_index, sw_if_index1, 1);
 	      goto trace01;
 	    }
 
 	  if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 	    {
-	      next1 = icmp_in2out_slow_path
-		(sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
-		 next1, now, thread_index, &s1);
-	      vlib_increment_simple_counter (is_slow_path ? &sm->
-					     counters.slowpath.in2out.
-					     icmp : &sm->counters.fastpath.
-					     in2out.icmp, thread_index,
-					     sw_if_index1, 1);
+	      next1 = nat44_ei_icmp_in2out_slow_path (
+		nm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node, next1,
+		now, thread_index, &s1);
+	      vlib_increment_simple_counter (
+		is_slow_path ? &nm->counters.slowpath.in2out.icmp :
+			       &nm->counters.fastpath.in2out.icmp,
+		thread_index, sw_if_index1, 1);
 	      goto trace01;
 	    }
 	}
@@ -1207,13 +1241,13 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	{
 	  if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
 	    {
-	      next1 = SNAT_IN2OUT_NEXT_SLOW_PATH;
+	      next1 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
 	      goto trace01;
 	    }
 
 	  if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
 	    {
-	      next1 = SNAT_IN2OUT_NEXT_SLOW_PATH;
+	      next1 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
 	      goto trace01;
 	    }
 	}
@@ -1221,19 +1255,18 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
       init_nat_k (&kv1, ip1->src_address,
 		  vnet_buffer (b1)->ip.reass.l4_src_port, rx_fib_index1,
 		  proto1);
-      if (PREDICT_FALSE (clib_bihash_search_8_8 (&sm->in2out, &kv1, &value1) !=
+      if (PREDICT_FALSE (clib_bihash_search_8_8 (&nm->in2out, &kv1, &value1) !=
 			 0))
 	{
 	  if (is_slow_path)
 	    {
 	      if (is_output_feature)
 		{
-		  if (PREDICT_FALSE
-		      (nat_not_translate_output_feature
-		       (sm, ip1, proto1,
+		  if (PREDICT_FALSE (nat44_ei_not_translate_output_feature (
+			nm, ip1, proto1,
 			vnet_buffer (b1)->ip.reass.l4_src_port,
-			vnet_buffer (b1)->ip.reass.l4_dst_port,
-			thread_index, sw_if_index1)))
+			vnet_buffer (b1)->ip.reass.l4_dst_port, thread_index,
+			sw_if_index1)))
 		    goto trace01;
 
 		  /*
@@ -1250,19 +1283,17 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		}
 	      else
 		{
-		  if (PREDICT_FALSE
-		      (snat_not_translate
-		       (sm, node, sw_if_index1, ip1, proto1,
-			rx_fib_index1, thread_index)))
+		  if (PREDICT_FALSE (nat44_ei_not_translate (
+			nm, node, sw_if_index1, ip1, proto1, rx_fib_index1,
+			thread_index)))
 		    goto trace01;
 		}
 
-	      next1 =
-		slow_path (sm, b1, ip1, ip1->src_address,
-			   vnet_buffer (b1)->ip.reass.l4_src_port,
-			   rx_fib_index1, proto1, &s1, node, next1,
-			   thread_index, now);
-	      if (PREDICT_FALSE (next1 == SNAT_IN2OUT_NEXT_DROP))
+	      next1 = slow_path (nm, b1, ip1, ip1->src_address,
+				 vnet_buffer (b1)->ip.reass.l4_src_port,
+				 rx_fib_index1, proto1, &s1, node, next1,
+				 thread_index, now);
+	      if (PREDICT_FALSE (next1 == NAT44_EI_IN2OUT_NEXT_DROP))
 		goto trace01;
 
 	      if (PREDICT_FALSE (!s1))
@@ -1270,12 +1301,12 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	    }
 	  else
 	    {
-	      next1 = SNAT_IN2OUT_NEXT_SLOW_PATH;
+	      next1 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
 	      goto trace01;
 	    }
 	}
       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));
 
       b1->flags |= VNET_BUFFER_F_IS_NATED;
@@ -1304,12 +1335,12 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	      sum1 = ip_csum_update (sum1, old_port1, new_port1,
 				     ip4_header_t /* cheat */ ,
 				     length /* changed member */ );
-	      mss_clamping (sm->mss_clamping, tcp1, &sum1);
+	      mss_clamping (nm->mss_clamping, tcp1, &sum1);
 	      tcp1->checksum = ip_csum_fold (sum1);
 	    }
-	  vlib_increment_simple_counter (is_slow_path ? &sm->
-					 counters.slowpath.in2out.tcp : &sm->
-					 counters.fastpath.in2out.tcp,
+	  vlib_increment_simple_counter (is_slow_path ?
+					   &nm->counters.slowpath.in2out.tcp :
+					   &nm->counters.fastpath.in2out.tcp,
 					 thread_index, sw_if_index1, 1);
 	}
       else
@@ -1331,9 +1362,9 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		  udp1->checksum = ip_csum_fold (sum1);
 		}
 	    }
-	  vlib_increment_simple_counter (is_slow_path ? &sm->
-					 counters.slowpath.in2out.udp : &sm->
-					 counters.fastpath.in2out.udp,
+	  vlib_increment_simple_counter (is_slow_path ?
+					   &nm->counters.slowpath.in2out.udp :
+					   &nm->counters.fastpath.in2out.udp,
 					 thread_index, sw_if_index1, 1);
 	}
 
@@ -1341,28 +1372,27 @@ snat_in2out_node_fn_inline (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);
     trace01:
 
       if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 			 && (b1->flags & VLIB_BUFFER_IS_TRACED)))
 	{
-	  snat_in2out_trace_t *t = vlib_add_trace (vm, node, b1, sizeof (*t));
+	  nat44_ei_in2out_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_IN2OUT_NEXT_DROP)
+      if (next1 == NAT44_EI_IN2OUT_NEXT_DROP)
 	{
-	  vlib_increment_simple_counter (is_slow_path ? &sm->
-					 counters.slowpath.in2out.
-					 drops : &sm->counters.fastpath.
-					 in2out.drops, thread_index,
-					 sw_if_index1, 1);
+	  vlib_increment_simple_counter (
+	    is_slow_path ? &nm->counters.slowpath.in2out.drops :
+			   &nm->counters.fastpath.in2out.drops,
+	    thread_index, sw_if_index1, 1);
 	}
 
       n_left_from -= 2;
@@ -1385,13 +1415,13 @@ snat_in2out_node_fn_inline (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;
       u32 iph_offset0 = 0;
 
       b0 = *b;
       b++;
-      next0 = SNAT_IN2OUT_NEXT_LOOKUP;
+      next0 = NAT44_EI_IN2OUT_NEXT_LOOKUP;
 
       if (is_output_feature)
 	iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;
@@ -1404,8 +1434,8 @@ snat_in2out_node_fn_inline (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))
 	{
@@ -1413,7 +1443,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	  icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
 				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
 				       0);
-	  next0 = SNAT_IN2OUT_NEXT_ICMP_ERROR;
+	  next0 = NAT44_EI_IN2OUT_NEXT_ICMP_ERROR;
 	  goto trace0;
 	}
 
@@ -1424,30 +1454,28 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	{
 	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 	    {
-	      if (nat_in2out_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
+	      if (nat_in2out_sm_unknown_proto (nm, b0, ip0, rx_fib_index0))
 		{
-		  next0 = SNAT_IN2OUT_NEXT_DROP;
+		  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
 		  b0->error =
-		    node->errors[SNAT_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
+		    node->errors[NAT44_EI_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
 		}
-	      vlib_increment_simple_counter (is_slow_path ? &sm->
-					     counters.slowpath.in2out.
-					     other : &sm->counters.fastpath.
-					     in2out.other, thread_index,
-					     sw_if_index0, 1);
+	      vlib_increment_simple_counter (
+		is_slow_path ? &nm->counters.slowpath.in2out.other :
+			       &nm->counters.fastpath.in2out.other,
+		thread_index, sw_if_index0, 1);
 	      goto trace0;
 	    }
 
 	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	    {
-	      next0 = icmp_in2out_slow_path
-		(sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-		 next0, now, thread_index, &s0);
-	      vlib_increment_simple_counter (is_slow_path ? &sm->
-					     counters.slowpath.in2out.
-					     icmp : &sm->counters.fastpath.
-					     in2out.icmp, thread_index,
-					     sw_if_index0, 1);
+	      next0 = nat44_ei_icmp_in2out_slow_path (
+		nm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node, next0,
+		now, thread_index, &s0);
+	      vlib_increment_simple_counter (
+		is_slow_path ? &nm->counters.slowpath.in2out.icmp :
+			       &nm->counters.fastpath.in2out.icmp,
+		thread_index, sw_if_index0, 1);
 	      goto trace0;
 	    }
 	}
@@ -1455,13 +1483,13 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	{
 	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
 	    {
-	      next0 = SNAT_IN2OUT_NEXT_SLOW_PATH;
+	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
 	      goto trace0;
 	    }
 
 	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	    {
-	      next0 = SNAT_IN2OUT_NEXT_SLOW_PATH;
+	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
 	      goto trace0;
 	    }
 	}
@@ -1470,18 +1498,17 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		  vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
 		  proto0);
 
-      if (clib_bihash_search_8_8 (&sm->in2out, &kv0, &value0))
+      if (clib_bihash_search_8_8 (&nm->in2out, &kv0, &value0))
 	{
 	  if (is_slow_path)
 	    {
 	      if (is_output_feature)
 		{
-		  if (PREDICT_FALSE
-		      (nat_not_translate_output_feature
-		       (sm, ip0, proto0,
+		  if (PREDICT_FALSE (nat44_ei_not_translate_output_feature (
+			nm, ip0, proto0,
 			vnet_buffer (b0)->ip.reass.l4_src_port,
-			vnet_buffer (b0)->ip.reass.l4_dst_port,
-			thread_index, sw_if_index0)))
+			vnet_buffer (b0)->ip.reass.l4_dst_port, thread_index,
+			sw_if_index0)))
 		    goto trace0;
 
 		  /*
@@ -1498,20 +1525,18 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		}
 	      else
 		{
-		  if (PREDICT_FALSE
-		      (snat_not_translate
-		       (sm, node, sw_if_index0, ip0, proto0, rx_fib_index0,
+		  if (PREDICT_FALSE (nat44_ei_not_translate (
+			nm, node, sw_if_index0, ip0, proto0, rx_fib_index0,
 			thread_index)))
 		    goto trace0;
 		}
 
-	      next0 =
-		slow_path (sm, b0, ip0, ip0->src_address,
-			   vnet_buffer (b0)->ip.reass.l4_src_port,
-			   rx_fib_index0, proto0, &s0, node, next0,
-			   thread_index, now);
+	      next0 = slow_path (nm, b0, ip0, ip0->src_address,
+				 vnet_buffer (b0)->ip.reass.l4_src_port,
+				 rx_fib_index0, proto0, &s0, node, next0,
+				 thread_index, now);
 
-	      if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
+	      if (PREDICT_FALSE (next0 == NAT44_EI_IN2OUT_NEXT_DROP))
 		goto trace0;
 
 	      if (PREDICT_FALSE (!s0))
@@ -1519,12 +1544,12 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	    }
 	  else
 	    {
-	      next0 = SNAT_IN2OUT_NEXT_SLOW_PATH;
+	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
 	      goto trace0;
 	    }
 	}
       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));
 
       b0->flags |= VNET_BUFFER_F_IS_NATED;
@@ -1554,12 +1579,12 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		ip_csum_update (sum0, old_port0, new_port0,
 				ip4_header_t /* cheat */ ,
 				length /* changed member */ );
-	      mss_clamping (sm->mss_clamping, tcp0, &sum0);
+	      mss_clamping (nm->mss_clamping, tcp0, &sum0);
 	      tcp0->checksum = ip_csum_fold (sum0);
 	    }
-	  vlib_increment_simple_counter (is_slow_path ? &sm->
-					 counters.slowpath.in2out.tcp : &sm->
-					 counters.fastpath.in2out.tcp,
+	  vlib_increment_simple_counter (is_slow_path ?
+					   &nm->counters.slowpath.in2out.tcp :
+					   &nm->counters.fastpath.in2out.tcp,
 					 thread_index, sw_if_index0, 1);
 	}
       else
@@ -1582,9 +1607,9 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		  udp0->checksum = ip_csum_fold (sum0);
 		}
 	    }
-	  vlib_increment_simple_counter (is_slow_path ? &sm->
-					 counters.slowpath.in2out.udp : &sm->
-					 counters.fastpath.in2out.udp,
+	  vlib_increment_simple_counter (is_slow_path ?
+					   &nm->counters.slowpath.in2out.udp :
+					   &nm->counters.fastpath.in2out.udp,
 					 thread_index, sw_if_index0, 1);
 	}
 
@@ -1592,29 +1617,28 @@ snat_in2out_node_fn_inline (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_in2out_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+	  nat44_ei_in2out_trace_t *t =
+	    vlib_add_trace (vm, node, b0, sizeof (*t));
 	  t->is_slow_path = is_slow_path;
 	  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_IN2OUT_NEXT_DROP)
+      if (next0 == NAT44_EI_IN2OUT_NEXT_DROP)
 	{
-	  vlib_increment_simple_counter (is_slow_path ? &sm->
-					 counters.slowpath.in2out.
-					 drops : &sm->counters.fastpath.
-					 in2out.drops, thread_index,
-					 sw_if_index0, 1);
+	  vlib_increment_simple_counter (
+	    is_slow_path ? &nm->counters.slowpath.in2out.drops :
+			   &nm->counters.fastpath.in2out.drops,
+	    thread_index, sw_if_index0, 1);
 	}
 
       n_left_from--;
@@ -1627,138 +1651,133 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
   return frame->n_vectors;
 }
 
-VLIB_NODE_FN (snat_in2out_node) (vlib_main_t * vm,
-				 vlib_node_runtime_t * node,
-				 vlib_frame_t * frame)
+VLIB_NODE_FN (nat44_ei_in2out_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return snat_in2out_node_fn_inline (vm, node, frame, 0 /* is_slow_path */ ,
-				     0);
+  return nat44_ei_in2out_node_fn_inline (vm, node, frame, 0 /* is_slow_path */,
+					 0);
 }
 
-VLIB_REGISTER_NODE (snat_in2out_node) = {
-  .name = "nat44-in2out",
+VLIB_REGISTER_NODE (nat44_ei_in2out_node) = {
+  .name = "nat44-ei-in2out",
   .vector_size = sizeof (u32),
-  .format_trace = format_snat_in2out_trace,
+  .format_trace = format_nat44_ei_in2out_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
 
-  .n_errors = ARRAY_LEN(snat_in2out_error_strings),
-  .error_strings = snat_in2out_error_strings,
+  .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
+  .error_strings = nat44_ei_in2out_error_strings,
 
-  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
 
-  .n_next_nodes = SNAT_IN2OUT_N_NEXT,
+  .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
 
   /* edit / add dispositions here */
   .next_nodes = {
-    [SNAT_IN2OUT_NEXT_DROP] = "error-drop",
-    [SNAT_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
-    [SNAT_IN2OUT_NEXT_SLOW_PATH] = "nat44-in2out-slowpath",
-    [SNAT_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
-    [SNAT_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-in2out-hairpinning-handoff-ip4-lookup",
+    [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
+    [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-slowpath",
+    [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-ip4-lookup",
   },
 };
 
-VLIB_NODE_FN (snat_in2out_output_node) (vlib_main_t * vm,
-					vlib_node_runtime_t * node,
-					vlib_frame_t * frame)
+VLIB_NODE_FN (nat44_ei_in2out_output_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return snat_in2out_node_fn_inline (vm, node, frame, 0 /* is_slow_path */ ,
-				     1);
+  return nat44_ei_in2out_node_fn_inline (vm, node, frame, 0 /* is_slow_path */,
+					 1);
 }
 
-VLIB_REGISTER_NODE (snat_in2out_output_node) = {
-  .name = "nat44-in2out-output",
+VLIB_REGISTER_NODE (nat44_ei_in2out_output_node) = {
+  .name = "nat44-ei-in2out-output",
   .vector_size = sizeof (u32),
-  .format_trace = format_snat_in2out_trace,
+  .format_trace = format_nat44_ei_in2out_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
 
-  .n_errors = ARRAY_LEN(snat_in2out_error_strings),
-  .error_strings = snat_in2out_error_strings,
+  .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
+  .error_strings = nat44_ei_in2out_error_strings,
 
-  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
 
-  .n_next_nodes = SNAT_IN2OUT_N_NEXT,
+  .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
 
   /* edit / add dispositions here */
   .next_nodes = {
-    [SNAT_IN2OUT_NEXT_DROP] = "error-drop",
-    [SNAT_IN2OUT_NEXT_LOOKUP] = "interface-output",
-    [SNAT_IN2OUT_NEXT_SLOW_PATH] = "nat44-in2out-output-slowpath",
-    [SNAT_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
-    [SNAT_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-in2out-hairpinning-handoff-interface-output",
+    [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
+    [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "interface-output",
+    [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-output-slowpath",
+    [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-interface-output",
   },
 };
 
-VLIB_NODE_FN (snat_in2out_slowpath_node) (vlib_main_t * vm,
-					  vlib_node_runtime_t * node,
-					  vlib_frame_t * frame)
+VLIB_NODE_FN (nat44_ei_in2out_slowpath_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return snat_in2out_node_fn_inline (vm, node, frame, 1 /* is_slow_path */ ,
-				     0);
+  return nat44_ei_in2out_node_fn_inline (vm, node, frame, 1 /* is_slow_path */,
+					 0);
 }
 
-VLIB_REGISTER_NODE (snat_in2out_slowpath_node) = {
-  .name = "nat44-in2out-slowpath",
+VLIB_REGISTER_NODE (nat44_ei_in2out_slowpath_node) = {
+  .name = "nat44-ei-in2out-slowpath",
   .vector_size = sizeof (u32),
-  .format_trace = format_snat_in2out_trace,
+  .format_trace = format_nat44_ei_in2out_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
 
-  .n_errors = ARRAY_LEN(snat_in2out_error_strings),
-  .error_strings = snat_in2out_error_strings,
+  .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
+  .error_strings = nat44_ei_in2out_error_strings,
 
-  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
 
-  .n_next_nodes = SNAT_IN2OUT_N_NEXT,
+  .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
 
   /* edit / add dispositions here */
   .next_nodes = {
-    [SNAT_IN2OUT_NEXT_DROP] = "error-drop",
-    [SNAT_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
-    [SNAT_IN2OUT_NEXT_SLOW_PATH] = "nat44-in2out-slowpath",
-    [SNAT_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
-    [SNAT_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-in2out-hairpinning-handoff-ip4-lookup",
+    [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
+    [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-slowpath",
+    [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-ip4-lookup",
   },
 };
 
-VLIB_NODE_FN (snat_in2out_output_slowpath_node) (vlib_main_t * vm,
-						 vlib_node_runtime_t * node,
-						 vlib_frame_t * frame)
+VLIB_NODE_FN (nat44_ei_in2out_output_slowpath_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return snat_in2out_node_fn_inline (vm, node, frame, 1 /* is_slow_path */ ,
-				     1);
+  return nat44_ei_in2out_node_fn_inline (vm, node, frame, 1 /* is_slow_path */,
+					 1);
 }
 
-VLIB_REGISTER_NODE (snat_in2out_output_slowpath_node) = {
-  .name = "nat44-in2out-output-slowpath",
+VLIB_REGISTER_NODE (nat44_ei_in2out_output_slowpath_node) = {
+  .name = "nat44-ei-in2out-output-slowpath",
   .vector_size = sizeof (u32),
-  .format_trace = format_snat_in2out_trace,
+  .format_trace = format_nat44_ei_in2out_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
 
-  .n_errors = ARRAY_LEN(snat_in2out_error_strings),
-  .error_strings = snat_in2out_error_strings,
+  .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
+  .error_strings = nat44_ei_in2out_error_strings,
 
-  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
 
-  .n_next_nodes = SNAT_IN2OUT_N_NEXT,
+  .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
 
   /* edit / add dispositions here */
   .next_nodes = {
-    [SNAT_IN2OUT_NEXT_DROP] = "error-drop",
-    [SNAT_IN2OUT_NEXT_LOOKUP] = "interface-output",
-    [SNAT_IN2OUT_NEXT_SLOW_PATH] = "nat44-in2out-output-slowpath",
-    [SNAT_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
-    [SNAT_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-in2out-hairpinning-handoff-interface-output",
+    [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
+    [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "interface-output",
+    [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-output-slowpath",
+    [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-interface-output",
   },
 };
 
-VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
-				      vlib_node_runtime_t * node,
-				      vlib_frame_t * frame)
+VLIB_NODE_FN (nat44_ei_in2out_fast_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
   u32 n_left_from, *from, *to_next;
   u32 thread_index = vm->thread_index;
-  snat_in2out_next_t next_index;
-  snat_main_t *sm = &snat_main;
+  nat44_ei_in2out_next_t next_index;
+  nat44_ei_main_t *nm = &nat44_ei_main;
   int is_hairpinning = 0;
 
   from = vlib_frame_vector_args (frame);
@@ -1800,7 +1819,7 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 	  n_left_to_next -= 1;
 
 	  b0 = vlib_get_buffer (vm, bi0);
-	  next0 = SNAT_IN2OUT_NEXT_LOOKUP;
+	  next0 = NAT44_EI_IN2OUT_NEXT_LOOKUP;
 
 	  ip0 = vlib_buffer_get_current (b0);
 	  udp0 = ip4_next_header (ip0);
@@ -1817,7 +1836,7 @@ VLIB_NODE_FN (snat_in2out_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_IN2OUT_NEXT_ICMP_ERROR;
+	      next0 = NAT44_EI_IN2OUT_NEXT_ICMP_ERROR;
 	      goto trace0;
 	    }
 
@@ -1828,8 +1847,8 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 
 	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
 	    {
-	      next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0,
-				   rx_fib_index0, node, next0, ~0, 0);
+	      next0 = nat44_ei_icmp_in2out (b0, ip0, icmp0, sw_if_index0,
+					    rx_fib_index0, node, next0, ~0, 0);
 	      goto trace0;
 	    }
 
@@ -1837,8 +1856,8 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 		ip0->src_address, udp0->src_port, rx_fib_index0, proto0,
 		&sm0_addr, &sm0_port, &sm0_fib_index, 0, 0, 0))
 	    {
-	      b0->error = node->errors[SNAT_IN2OUT_ERROR_NO_TRANSLATION];
-	      next0 = SNAT_IN2OUT_NEXT_DROP;
+	      b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_NO_TRANSLATION];
+	      next0 = NAT44_EI_IN2OUT_NEXT_DROP;
 	      goto trace0;
 	    }
 
@@ -1868,7 +1887,7 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
 					 ip4_header_t /* cheat */ ,
 					 length /* changed member */ );
-		  mss_clamping (sm->mss_clamping, tcp0, &sum0);
+		  mss_clamping (nm->mss_clamping, tcp0, &sum0);
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
 	      else if (udp0->checksum)
@@ -1891,7 +1910,7 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
 					 ip4_header_t,
 					 dst_address /* changed member */ );
-		  mss_clamping (sm->mss_clamping, tcp0, &sum0);
+		  mss_clamping (nm->mss_clamping, tcp0, &sum0);
 		  tcp0->checksum = ip_csum_fold (sum0);
 		}
 	      else if (udp0->checksum)
@@ -1905,34 +1924,34 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
 	    }
 
 	  /* Hairpinning */
-	  is_hairpinning = snat_hairpinning (
-	    vm, node, sm, thread_index, b0, ip0, udp0, tcp0, proto0,
+	  is_hairpinning = nat44_ei_hairpinning (
+	    vm, node, nm, thread_index, b0, ip0, udp0, tcp0, proto0,
 	    0 /* do_trace */, &required_thread_index);
 
 	  if (thread_index != required_thread_index)
 	    {
 	      vnet_buffer (b0)->snat.required_thread_index =
 		required_thread_index;
-	      next0 = SNAT_IN2OUT_NEXT_HAIRPINNING_HANDOFF;
+	      next0 = NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF;
 	    }
 
 	trace0:
 	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
 			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
 	    {
-	      snat_in2out_trace_t *t =
+	      nat44_ei_in2out_trace_t *t =
 		vlib_add_trace (vm, node, b0, sizeof (*t));
 	      t->sw_if_index = sw_if_index0;
 	      t->next_index = next0;
 	      t->is_hairpinning = is_hairpinning;
 	    }
 
-	  if (next0 != SNAT_IN2OUT_NEXT_DROP)
+	  if (next0 != NAT44_EI_IN2OUT_NEXT_DROP)
 	    {
 
-	      vlib_increment_simple_counter (&sm->counters.fastpath.
-					     in2out.other, sw_if_index0,
-					     vm->thread_index, 1);
+	      vlib_increment_simple_counter (
+		&nm->counters.fastpath.in2out.other, sw_if_index0,
+		vm->thread_index, 1);
 	    }
 
 	  /* verify speculative enqueue, maybe switch current next frame */
@@ -1947,43 +1966,43 @@ VLIB_NODE_FN (snat_in2out_fast_node) (vlib_main_t * vm,
   return frame->n_vectors;
 }
 
-VLIB_REGISTER_NODE (snat_in2out_fast_node) = {
-  .name = "nat44-in2out-fast",
+VLIB_REGISTER_NODE (nat44_ei_in2out_fast_node) = {
+  .name = "nat44-ei-in2out-fast",
   .vector_size = sizeof (u32),
-  .format_trace = format_snat_in2out_fast_trace,
+  .format_trace = format_nat44_ei_in2out_fast_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
 
-  .n_errors = ARRAY_LEN(snat_in2out_error_strings),
-  .error_strings = snat_in2out_error_strings,
+  .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
+  .error_strings = nat44_ei_in2out_error_strings,
 
-  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
 
-  .n_next_nodes = SNAT_IN2OUT_N_NEXT,
+  .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
 
   /* edit / add dispositions here */
   .next_nodes = {
-    [SNAT_IN2OUT_NEXT_DROP] = "error-drop",
-    [SNAT_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
-    [SNAT_IN2OUT_NEXT_SLOW_PATH] = "nat44-in2out-slowpath",
-    [SNAT_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
-    [SNAT_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-in2out-hairpinning-handoff-ip4-lookup",
+    [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
+    [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-slowpath",
+    [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-ip4-lookup",
   },
 };
 
-VLIB_NODE_FN (nat44_in2out_hairpinning_handoff_ip4_lookup_node)
+VLIB_NODE_FN (nat44_ei_in2out_hairpinning_handoff_ip4_lookup_node)
 (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return nat44_hairpinning_handoff_fn_inline (
+  return nat44_ei_hairpinning_handoff_fn_inline (
     vm, node, frame,
-    snat_main.nat44_in2out_hairpinning_finish_ip4_lookup_node_fq_index);
+    nat44_ei_main.in2out_hairpinning_finish_ip4_lookup_node_fq_index);
 }
 
-VLIB_REGISTER_NODE (nat44_in2out_hairpinning_handoff_ip4_lookup_node) = {
-  .name = "nat44-in2out-hairpinning-handoff-ip4-lookup",
+VLIB_REGISTER_NODE (nat44_ei_in2out_hairpinning_handoff_ip4_lookup_node) = {
+  .name = "nat44-ei-in2out-hairpinning-handoff-ip4-lookup",
   .vector_size = sizeof (u32),
-  .n_errors = ARRAY_LEN(nat44_hairpinning_handoff_error_strings),
-  .error_strings = nat44_hairpinning_handoff_error_strings,
-  .format_trace = format_nat44_hairpinning_handoff_trace,
+  .n_errors = ARRAY_LEN(nat44_ei_hairpinning_handoff_error_strings),
+  .error_strings = nat44_ei_hairpinning_handoff_error_strings,
+  .format_trace = format_nat44_ei_hairpinning_handoff_trace,
 
   .n_next_nodes = 1,
 
@@ -1992,20 +2011,20 @@ VLIB_REGISTER_NODE (nat44_in2out_hairpinning_handoff_ip4_lookup_node) = {
   },
 };
 
-VLIB_NODE_FN (nat44_in2out_hairpinning_handoff_interface_output_node)
+VLIB_NODE_FN (nat44_ei_in2out_hairpinning_handoff_interface_output_node)
 (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return nat44_hairpinning_handoff_fn_inline (
+  return nat44_ei_hairpinning_handoff_fn_inline (
     vm, node, frame,
-    snat_main.nat44_in2out_hairpinning_finish_interface_output_node_fq_index);
+    nat44_ei_main.in2out_hairpinning_finish_interface_output_node_fq_index);
 }
 
-VLIB_REGISTER_NODE (nat44_in2out_hairpinning_handoff_interface_output_node) = {
-  .name = "nat44-in2out-hairpinning-handoff-interface-output",
+VLIB_REGISTER_NODE (nat44_ei_in2out_hairpinning_handoff_interface_output_node) = {
+  .name = "nat44-ei-in2out-hairpinning-handoff-interface-output",
   .vector_size = sizeof (u32),
-  .n_errors = ARRAY_LEN(nat44_hairpinning_handoff_error_strings),
-  .error_strings = nat44_hairpinning_handoff_error_strings,
-  .format_trace = format_nat44_hairpinning_handoff_trace,
+  .n_errors = ARRAY_LEN(nat44_ei_hairpinning_handoff_error_strings),
+  .error_strings = nat44_ei_hairpinning_handoff_error_strings,
+  .format_trace = format_nat44_ei_hairpinning_handoff_trace,
 
   .n_next_nodes = 1,
 
@@ -2015,14 +2034,14 @@ VLIB_REGISTER_NODE (nat44_in2out_hairpinning_handoff_interface_output_node) = {
 };
 
 static_always_inline int
-nat44_in2out_hairpinning_finish_inline (vlib_main_t *vm,
-					vlib_node_runtime_t *node,
-					vlib_frame_t *frame)
+nat44_ei_in2out_hairpinning_finish_inline (vlib_main_t *vm,
+					   vlib_node_runtime_t *node,
+					   vlib_frame_t *frame)
 {
   u32 n_left_from, *from, *to_next;
   u32 thread_index = vm->thread_index;
-  snat_in2out_next_t next_index;
-  snat_main_t *sm = &snat_main;
+  nat44_ei_in2out_next_t next_index;
+  nat44_ei_main_t *nm = &nat44_ei_main;
   int is_hairpinning = 0;
 
   from = vlib_frame_vector_args (frame);
@@ -2057,7 +2076,7 @@ nat44_in2out_hairpinning_finish_inline (vlib_main_t *vm,
 	  n_left_to_next -= 1;
 
 	  b0 = vlib_get_buffer (vm, bi0);
-	  next0 = NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP;
+	  next0 = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP;
 
 	  ip0 = vlib_buffer_get_current (b0);
 	  udp0 = ip4_next_header (ip0);
@@ -2072,41 +2091,41 @@ nat44_in2out_hairpinning_finish_inline (vlib_main_t *vm,
 	    case NAT_PROTOCOL_TCP:
 	      // fallthrough
 	    case NAT_PROTOCOL_UDP:
-	      is_hairpinning = snat_hairpinning (
-		vm, node, sm, thread_index, b0, ip0, udp0, tcp0, proto0,
+	      is_hairpinning = nat44_ei_hairpinning (
+		vm, node, nm, thread_index, b0, ip0, udp0, tcp0, proto0,
 		0 /* do_trace */, &required_thread_index);
 	      break;
 	    case NAT_PROTOCOL_ICMP:
-	      is_hairpinning =
-		(0 == snat_icmp_hairpinning (sm, b0, thread_index, ip0, icmp0,
-					     &required_thread_index));
+	      is_hairpinning = (0 == nat44_ei_icmp_hairpinning (
+				       nm, b0, thread_index, ip0, icmp0,
+				       &required_thread_index));
 	      break;
 	    case NAT_PROTOCOL_OTHER:
 	      // this should never happen
-	      next0 = NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP;
+	      next0 = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP;
 	      break;
 	    }
 
 	  if (thread_index != required_thread_index)
 	    {
 	      // but we already did a handoff ...
-	      next0 = NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP;
+	      next0 = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP;
 	    }
 
 	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
 			     (b0->flags & VLIB_BUFFER_IS_TRACED)))
 	    {
-	      snat_in2out_trace_t *t =
+	      nat44_ei_in2out_trace_t *t =
 		vlib_add_trace (vm, node, b0, sizeof (*t));
 	      t->sw_if_index = sw_if_index0;
 	      t->next_index = next0;
 	      t->is_hairpinning = is_hairpinning;
 	    }
 
-	  if (next0 != NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP)
+	  if (next0 != NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP)
 	    {
 	      vlib_increment_simple_counter (
-		&sm->counters.fastpath.in2out.other, sw_if_index0,
+		&nm->counters.fastpath.in2out.other, sw_if_index0,
 		vm->thread_index, 1);
 	    }
 
@@ -2121,55 +2140,55 @@ nat44_in2out_hairpinning_finish_inline (vlib_main_t *vm,
   return frame->n_vectors;
 }
 
-VLIB_NODE_FN (nat44_in2out_hairpinning_finish_ip4_lookup_node)
+VLIB_NODE_FN (nat44_ei_in2out_hairpinning_finish_ip4_lookup_node)
 (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return nat44_in2out_hairpinning_finish_inline (vm, node, frame);
+  return nat44_ei_in2out_hairpinning_finish_inline (vm, node, frame);
 }
 
-VLIB_REGISTER_NODE (nat44_in2out_hairpinning_finish_ip4_lookup_node) = {
-  .name = "nat44-in2out-hairpinning-finish-ip4-lookup",
+VLIB_REGISTER_NODE (nat44_ei_in2out_hairpinning_finish_ip4_lookup_node) = {
+  .name = "nat44-ei-in2out-hairpinning-finish-ip4-lookup",
   .vector_size = sizeof (u32),
-  .format_trace = format_snat_in2out_fast_trace,
+  .format_trace = format_nat44_ei_in2out_fast_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
 
-  .n_errors = ARRAY_LEN(snat_in2out_error_strings),
-  .error_strings = snat_in2out_error_strings,
+  .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
+  .error_strings = nat44_ei_in2out_error_strings,
 
-  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
 
-  .n_next_nodes = NAT44_IN2OUT_HAIRPINNING_FINISH_N_NEXT,
+  .n_next_nodes = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_N_NEXT,
 
   /* edit / add dispositions here */
   .next_nodes = {
-    [NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP] = "error-drop",
-    [NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP] = "error-drop",
+    [NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP] = "ip4-lookup",
   },
 };
 
-VLIB_NODE_FN (nat44_in2out_hairpinning_finish_interface_output_node)
+VLIB_NODE_FN (nat44_ei_in2out_hairpinning_finish_interface_output_node)
 (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 {
-  return nat44_in2out_hairpinning_finish_inline (vm, node, frame);
+  return nat44_ei_in2out_hairpinning_finish_inline (vm, node, frame);
 }
 
-VLIB_REGISTER_NODE (nat44_in2out_hairpinning_finish_interface_output_node) = {
-  .name = "nat44-in2out-hairpinning-finish-interface-output",
+VLIB_REGISTER_NODE (nat44_ei_in2out_hairpinning_finish_interface_output_node) = {
+  .name = "nat44-ei-in2out-hairpinning-finish-interface-output",
   .vector_size = sizeof (u32),
-  .format_trace = format_snat_in2out_fast_trace,
+  .format_trace = format_nat44_ei_in2out_fast_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
 
-  .n_errors = ARRAY_LEN(snat_in2out_error_strings),
-  .error_strings = snat_in2out_error_strings,
+  .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
+  .error_strings = nat44_ei_in2out_error_strings,
 
-  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
 
-  .n_next_nodes = NAT44_IN2OUT_HAIRPINNING_FINISH_N_NEXT,
+  .n_next_nodes = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_N_NEXT,
 
   /* edit / add dispositions here */
   .next_nodes = {
-    [NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP] = "error-drop",
-    [NAT44_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP] = "interface-output",
+    [NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP] = "error-drop",
+    [NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP] = "interface-output",
   },
 };