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, 2063 insertions, 366 deletions

diff --git a/src/plugins/nat/nat44-ei/nat44_ei.c b/src/plugins/nat/nat44-ei/nat44_ei.c
index 02403d0cd99..fdf90708a09 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei.c
@@ -15,42 +15,409 @@
  * under the License.
  */
 
+#include <vnet/plugin/plugin.h>
+#include <vpp/app/version.h>
+
 #include <vnet/vnet.h>
 #include <vnet/ip/ip.h>
 #include <vnet/ip/ip4.h>
-#include <vnet/plugin/plugin.h>
-#include <nat/nat.h>
-#include <nat/nat_dpo.h>
-#include <nat/lib/ipfix_logging.h>
-#include <nat/lib/nat_syslog.h>
-#include <nat/nat_inlines.h>
-#include <nat/nat44/inlines.h>
-#include <nat/nat_affinity.h>
+#include <vnet/ip/ip_table.h>
+#include <vnet/ip/reass/ip4_sv_reass.h>
 #include <vnet/fib/fib_table.h>
 #include <vnet/fib/ip4_fib.h>
-#include <vnet/ip/reass/ip4_sv_reass.h>
-#include <vppinfra/bihash_16_8.h>
-#include <nat/nat44/ed_inlines.h>
-#include <vnet/ip/ip_table.h>
+#include <vnet/plugin/plugin.h>
 
+// nat lib
+#include <nat/lib/log.h>
+#include <nat/lib/nat_syslog.h>
+#include <nat/lib/nat_inlines.h>
+#include <nat/lib/ipfix_logging.h>
+
+#include <nat/nat44-ei/nat44_ei_dpo.h>
 #include <nat/nat44-ei/nat44_ei_inlines.h>
 #include <nat/nat44-ei/nat44_ei.h>
 
 nat44_ei_main_t nat44_ei_main;
 
+extern vlib_node_registration_t nat44_ei_hairpinning_node;
+extern vlib_node_registration_t nat44_ei_hairpin_dst_node;
+extern vlib_node_registration_t
+  nat44_ei_in2out_hairpinning_finish_ip4_lookup_node;
+extern vlib_node_registration_t
+  nat44_ei_in2out_hairpinning_finish_interface_output_node;
+
+#define skip_if_disabled()                                                    \
+  do                                                                          \
+    {                                                                         \
+      nat44_ei_main_t *nm = &nat44_ei_main;                                   \
+      if (PREDICT_FALSE (!nm->enabled))                                       \
+	return;                                                               \
+    }                                                                         \
+  while (0)
+
+#define fail_if_enabled()                                                     \
+  do                                                                          \
+    {                                                                         \
+      nat44_ei_main_t *nm = &nat44_ei_main;                                   \
+      if (PREDICT_FALSE (nm->enabled))                                        \
+	{                                                                     \
+	  nat44_ei_log_err ("plugin enabled");                                \
+	  return 1;                                                           \
+	}                                                                     \
+    }                                                                         \
+  while (0)
+
+#define fail_if_disabled()                                                    \
+  do                                                                          \
+    {                                                                         \
+      nat44_ei_main_t *nm = &nat44_ei_main;                                   \
+      if (PREDICT_FALSE (!nm->enabled))                                       \
+	{                                                                     \
+	  nat44_ei_log_err ("plugin disabled");                               \
+	  return 1;                                                           \
+	}                                                                     \
+    }                                                                         \
+  while (0)
+
+/* Hook up input features */
+VNET_FEATURE_INIT (ip4_nat_classify, static) = {
+  .arc_name = "ip4-unicast",
+  .node_name = "nat44-ei-classify",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+			       "ip4-sv-reassembly-feature"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_in2out, static) = {
+  .arc_name = "ip4-unicast",
+  .node_name = "nat44-ei-in2out",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+			       "ip4-sv-reassembly-feature"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_out2in, static) = {
+  .arc_name = "ip4-unicast",
+  .node_name = "nat44-ei-out2in",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+			       "ip4-sv-reassembly-feature",
+			       "ip4-dhcp-client-detect"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_in2out_output, static) = {
+  .arc_name = "ip4-output",
+  .node_name = "nat44-ei-in2out-output",
+  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa",
+			       "ip4-sv-reassembly-output-feature"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_in2out_fast, static) = {
+  .arc_name = "ip4-unicast",
+  .node_name = "nat44-ei-in2out-fast",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+			       "ip4-sv-reassembly-feature"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_out2in_fast, static) = {
+  .arc_name = "ip4-unicast",
+  .node_name = "nat44-ei-out2in-fast",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+			       "ip4-sv-reassembly-feature",
+			       "ip4-dhcp-client-detect"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_hairpin_dst, static) = {
+  .arc_name = "ip4-unicast",
+  .node_name = "nat44-ei-hairpin-dst",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+			       "ip4-sv-reassembly-feature"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_hairpin_src, static) = {
+  .arc_name = "ip4-output",
+  .node_name = "nat44-ei-hairpin-src",
+  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa",
+			       "ip4-sv-reassembly-output-feature"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_hairpinning, static) = {
+  .arc_name = "ip4-local",
+  .node_name = "nat44-ei-hairpinning",
+  .runs_before = VNET_FEATURES ("ip4-local-end-of-arc"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_in2out_worker_handoff, static) = {
+  .arc_name = "ip4-unicast",
+  .node_name = "nat44-ei-in2out-worker-handoff",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_out2in_worker_handoff, static) = {
+  .arc_name = "ip4-unicast",
+  .node_name = "nat44-ei-out2in-worker-handoff",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+			       "ip4-dhcp-client-detect"),
+};
+VNET_FEATURE_INIT (ip4_nat44_ei_in2out_output_worker_handoff, static) = {
+  .arc_name = "ip4-output",
+  .node_name = "nat44-ei-in2out-output-worker-handoff",
+  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa",
+			       "ip4-sv-reassembly-output-feature"),
+};
+
+VLIB_PLUGIN_REGISTER () = {
+  .version = VPP_BUILD_VER,
+  .description = "IPv4 Endpoint-Independent NAT (NAT44 EI)",
+};
+
+#define foreach_nat44_ei_classify_error                                       \
+  _ (NEXT_IN2OUT, "next in2out")                                              \
+  _ (NEXT_OUT2IN, "next out2in")                                              \
+  _ (FRAG_CACHED, "fragment cached")
+
+typedef enum
+{
+#define _(sym, str) NAT44_EI_CLASSIFY_ERROR_##sym,
+  foreach_nat44_ei_classify_error
+#undef _
+    NAT44_EI_CLASSIFY_N_ERROR,
+} nat44_ei_classify_error_t;
+
+static char *nat44_ei_classify_error_strings[] = {
+#define _(sym, string) string,
+  foreach_nat44_ei_classify_error
+#undef _
+};
+
+typedef enum
+{
+  NAT44_EI_CLASSIFY_NEXT_IN2OUT,
+  NAT44_EI_CLASSIFY_NEXT_OUT2IN,
+  NAT44_EI_CLASSIFY_NEXT_DROP,
+  NAT44_EI_CLASSIFY_N_NEXT,
+} nat44_ei_classify_next_t;
+
+typedef struct
+{
+  u8 next_in2out;
+  u8 cached;
+} nat44_ei_classify_trace_t;
+
+void nat44_ei_add_del_addr_to_fib (ip4_address_t *addr, u8 p_len,
+				   u32 sw_if_index, int is_add);
+
+static u8 *
+format_nat44_ei_classify_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 *);
+  nat44_ei_classify_trace_t *t = va_arg (*args, nat44_ei_classify_trace_t *);
+  char *next;
+
+  if (t->cached)
+    s = format (s, "nat44-ei-classify: fragment cached");
+  else
+    {
+      next = t->next_in2out ? "nat44-ei-in2out" : "nat44-ei-out2in";
+      s = format (s, "nat44-ei-classify: next %s", next);
+    }
+
+  return s;
+}
+
 static void nat44_ei_db_free ();
 
 static void nat44_ei_db_init (u32 translations, u32 translation_buckets,
 			      u32 user_buckets);
 
+static void nat44_ei_ip4_add_del_interface_address_cb (
+  ip4_main_t *im, uword opaque, u32 sw_if_index, ip4_address_t *address,
+  u32 address_length, u32 if_address_index, u32 is_delete);
+
+static void nat44_ei_ip4_add_del_addr_only_sm_cb (
+  ip4_main_t *im, uword opaque, u32 sw_if_index, ip4_address_t *address,
+  u32 address_length, u32 if_address_index, u32 is_delete);
+
+static void nat44_ei_update_outside_fib (ip4_main_t *im, uword opaque,
+					 u32 sw_if_index, u32 new_fib_index,
+					 u32 old_fib_index);
+
+void
+nat44_ei_set_node_indexes (nat44_ei_main_t *nm, vlib_main_t *vm)
+{
+  vlib_node_t *node;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ei-out2in");
+  nm->out2in_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ei-in2out");
+  nm->in2out_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ei-in2out-output");
+  nm->in2out_output_node_index = node->index;
+}
+
 int
-nat44_ei_plugin_enable (nat44_ei_config_t c)
+nat44_ei_set_workers (uword *bitmap)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  int i, j = 0;
+
+  if (nm->num_workers < 2)
+    return VNET_API_ERROR_FEATURE_DISABLED;
+
+  if (clib_bitmap_last_set (bitmap) >= nm->num_workers)
+    return VNET_API_ERROR_INVALID_WORKER;
+
+  vec_free (nm->workers);
+  clib_bitmap_foreach (i, bitmap)
+    {
+      vec_add1 (nm->workers, i);
+      nm->per_thread_data[nm->first_worker_index + i].snat_thread_index = j;
+      nm->per_thread_data[nm->first_worker_index + i].thread_index = i;
+      j++;
+    }
+
+  nm->port_per_thread = (0xffff - 1024) / _vec_len (nm->workers);
+
+  return 0;
+}
+
+#define nat_validate_simple_counter(c, i)                                     \
+  do                                                                          \
+    {                                                                         \
+      vlib_validate_simple_counter (&c, i);                                   \
+      vlib_zero_simple_counter (&c, i);                                       \
+    }                                                                         \
+  while (0);
+
+#define nat_init_simple_counter(c, n, sn)                                     \
+  do                                                                          \
+    {                                                                         \
+      c.name = n;                                                             \
+      c.stat_segment_name = sn;                                               \
+      nat_validate_simple_counter (c, 0);                                     \
+    }                                                                         \
+  while (0);
+
+static_always_inline void
+nat_validate_interface_counters (nat44_ei_main_t *nm, u32 sw_if_index)
+{
+#define _(x)                                                                  \
+  nat_validate_simple_counter (nm->counters.fastpath.in2out.x, sw_if_index);  \
+  nat_validate_simple_counter (nm->counters.fastpath.out2in.x, sw_if_index);  \
+  nat_validate_simple_counter (nm->counters.slowpath.in2out.x, sw_if_index);  \
+  nat_validate_simple_counter (nm->counters.slowpath.out2in.x, sw_if_index);
+  foreach_nat_counter;
+#undef _
+  nat_validate_simple_counter (nm->counters.hairpinning, sw_if_index);
+}
+
+clib_error_t *
+nat44_ei_init (vlib_main_t *vm)
 {
   nat44_ei_main_t *nm = &nat44_ei_main;
-  snat_main_t *sm = &snat_main;
+  vlib_thread_main_t *tm = vlib_get_thread_main ();
+  vlib_thread_registration_t *tr;
+  ip4_add_del_interface_address_callback_t cbi = { 0 };
+  ip4_table_bind_callback_t cbt = { 0 };
+  u32 i, num_threads = 0;
+  uword *p, *bitmap = 0;
 
   clib_memset (nm, 0, sizeof (*nm));
 
+  // required
+  nm->vnet_main = vnet_get_main ();
+  // convenience
+  nm->ip4_main = &ip4_main;
+  nm->api_main = vlibapi_get_main ();
+  nm->ip4_lookup_main = &ip4_main.lookup_main;
+
+  // handoff stuff
+  nm->fq_out2in_index = ~0;
+  nm->fq_in2out_index = ~0;
+  nm->fq_in2out_output_index = ~0;
+  nm->worker_in2out_cb = nat44_ei_get_in2out_worker_index;
+  nm->worker_out2in_cb = nat44_ei_get_out2in_worker_index;
+
+  nm->log_level = NAT_LOG_ERROR;
+
+  nat44_ei_set_node_indexes (nm, vm);
+  nm->log_class = vlib_log_register_class ("nat44-ei", 0);
+
+  nat_init_simple_counter (nm->total_users, "total-users",
+			   "/nat44-ei/total-users");
+  nat_init_simple_counter (nm->total_sessions, "total-sessions",
+			   "/nat44-ei/total-sessions");
+  nat_init_simple_counter (nm->user_limit_reached, "user-limit-reached",
+			   "/nat44-ei/user-limit-reached");
+
+#define _(x)                                                                  \
+  nat_init_simple_counter (nm->counters.fastpath.in2out.x, #x,                \
+			   "/nat44-ei/in2out/fastpath/" #x);                  \
+  nat_init_simple_counter (nm->counters.fastpath.out2in.x, #x,                \
+			   "/nat44-ei/out2in/fastpath/" #x);                  \
+  nat_init_simple_counter (nm->counters.slowpath.in2out.x, #x,                \
+			   "/nat44-ei/in2out/slowpath/" #x);                  \
+  nat_init_simple_counter (nm->counters.slowpath.out2in.x, #x,                \
+			   "/nat44-ei/out2in/slowpath/" #x);
+  foreach_nat_counter;
+#undef _
+  nat_init_simple_counter (nm->counters.hairpinning, "hairpinning",
+			   "/nat44-ei/hairpinning");
+
+  p = hash_get_mem (tm->thread_registrations_by_name, "workers");
+  if (p)
+    {
+      tr = (vlib_thread_registration_t *) p[0];
+      if (tr)
+	{
+	  nm->num_workers = tr->count;
+	  nm->first_worker_index = tr->first_index;
+	}
+    }
+  num_threads = tm->n_vlib_mains - 1;
+  nm->port_per_thread = 0xffff - 1024;
+  vec_validate (nm->per_thread_data, num_threads);
+
+  /* Use all available workers by default */
+  if (nm->num_workers > 1)
+    {
+
+      for (i = 0; i < nm->num_workers; i++)
+	bitmap = clib_bitmap_set (bitmap, i, 1);
+      nat44_ei_set_workers (bitmap);
+      clib_bitmap_free (bitmap);
+    }
+  else
+    nm->per_thread_data[0].snat_thread_index = 0;
+
+  /* callbacks to call when interface address changes. */
+  cbi.function = nat44_ei_ip4_add_del_interface_address_cb;
+  vec_add1 (nm->ip4_main->add_del_interface_address_callbacks, cbi);
+  cbi.function = nat44_ei_ip4_add_del_addr_only_sm_cb;
+  vec_add1 (nm->ip4_main->add_del_interface_address_callbacks, cbi);
+
+  /* callbacks to call when interface to table biding changes */
+  cbt.function = nat44_ei_update_outside_fib;
+  vec_add1 (nm->ip4_main->table_bind_callbacks, cbt);
+
+  nm->fib_src_low = fib_source_allocate (
+    "nat44-ei-low", FIB_SOURCE_PRIORITY_LOW, FIB_SOURCE_BH_SIMPLE);
+  nm->fib_src_hi = fib_source_allocate ("nat44-ei-hi", FIB_SOURCE_PRIORITY_HI,
+					FIB_SOURCE_BH_SIMPLE);
+
+  // used only by out2in-dpo feature
+  nat_dpo_module_init ();
+  nat_ha_init (vm, nm->num_workers, num_threads);
+
+  nm->hairpinning_fq_index =
+    vlib_frame_queue_main_init (nat44_ei_hairpinning_node.index, 0);
+  nm->hairpin_dst_fq_index =
+    vlib_frame_queue_main_init (nat44_ei_hairpin_dst_node.index, 0);
+  nm->in2out_hairpinning_finish_ip4_lookup_node_fq_index =
+    vlib_frame_queue_main_init (
+      nat44_ei_in2out_hairpinning_finish_ip4_lookup_node.index, 0);
+  nm->in2out_hairpinning_finish_interface_output_node_fq_index =
+    vlib_frame_queue_main_init (
+      nat44_ei_in2out_hairpinning_finish_interface_output_node.index, 0);
+  return nat44_ei_api_hookup (vm);
+}
+
+VLIB_INIT_FUNCTION (nat44_ei_init);
+
+int
+nat44_ei_plugin_enable (nat44_ei_config_t c)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+
+  fail_if_enabled ();
+
   if (!c.users)
     c.users = 1024;
 
@@ -59,68 +426,449 @@ nat44_ei_plugin_enable (nat44_ei_config_t c)
 
   nm->rconfig = c;
 
+  if (!nm->frame_queue_nelts)
+    nm->frame_queue_nelts = NAT_FQ_NELTS_DEFAULT;
+
   nm->translations = c.sessions;
   nm->translation_buckets = nat_calc_bihash_buckets (c.sessions);
   nm->user_buckets = nat_calc_bihash_buckets (c.users);
 
-  // OBSOLETE
-
-  sm->static_mapping_only = c.static_mapping_only;
-  sm->static_mapping_connection_tracking = c.connection_tracking;
-  sm->out2in_dpo = c.out2in_dpo;
-  sm->forwarding_enabled = 0;
-  sm->mss_clamping = 0;
-  sm->pat = (!c.static_mapping_only ||
+  nm->pat = (!c.static_mapping_only ||
 	     (c.static_mapping_only && c.connection_tracking));
 
-  sm->max_users_per_thread = c.users;
-  sm->max_translations_per_thread = c.sessions;
-  sm->translation_buckets = nat_calc_bihash_buckets (c.sessions);
-  sm->max_translations_per_user =
-    c.user_sessions ? c.user_sessions : sm->max_translations_per_thread;
+  nm->static_mapping_only = c.static_mapping_only;
+  nm->static_mapping_connection_tracking = c.connection_tracking;
+  nm->out2in_dpo = c.out2in_dpo;
+  nm->forwarding_enabled = 0;
+  nm->mss_clamping = 0;
 
-  sm->inside_vrf_id = c.inside_vrf;
-  sm->inside_fib_index = fib_table_find_or_create_and_lock (
-    FIB_PROTOCOL_IP4, c.inside_vrf, sm->fib_src_hi);
+  nm->max_users_per_thread = c.users;
+  nm->max_translations_per_thread = c.sessions;
+  nm->max_translations_per_user =
+    c.user_sessions ? c.user_sessions : nm->max_translations_per_thread;
 
-  sm->outside_vrf_id = c.outside_vrf;
-  sm->outside_fib_index = fib_table_find_or_create_and_lock (
-    FIB_PROTOCOL_IP4, c.outside_vrf, sm->fib_src_hi);
+  nm->inside_vrf_id = c.inside_vrf;
+  nm->inside_fib_index = fib_table_find_or_create_and_lock (
+    FIB_PROTOCOL_IP4, c.inside_vrf, nm->fib_src_hi);
 
-  sm->worker_in2out_cb = nat44_ei_get_in2out_worker_index;
-  sm->worker_out2in_cb = nat44_ei_get_out2in_worker_index;
+  nm->outside_vrf_id = c.outside_vrf;
+  nm->outside_fib_index = fib_table_find_or_create_and_lock (
+    FIB_PROTOCOL_IP4, c.outside_vrf, nm->fib_src_hi);
 
-  sm->in2out_node_index = sm->ei_in2out_node_index;
-  sm->out2in_node_index = sm->ei_out2in_node_index;
+  nat_reset_timeouts (&nm->timeouts);
+  nat44_ei_db_init (nm->translations, nm->translation_buckets,
+		    nm->user_buckets);
+  nat44_ei_set_alloc_default ();
 
-  sm->in2out_output_node_index = sm->ei_in2out_output_node_index;
+  // TODO: zero simple counter for all counters missing
 
-  if (sm->pat)
+  vlib_zero_simple_counter (&nm->total_users, 0);
+  vlib_zero_simple_counter (&nm->total_sessions, 0);
+  vlib_zero_simple_counter (&nm->user_limit_reached, 0);
+
+  nat_ha_enable ();
+  nm->enabled = 1;
+
+  return 0;
+}
+
+void
+nat44_ei_addresses_free (nat44_ei_address_t **addresses)
+{
+  nat44_ei_address_t *ap;
+  vec_foreach (ap, *addresses)
     {
-      sm->icmp_match_in2out_cb = icmp_match_in2out_slow;
-      sm->icmp_match_out2in_cb = icmp_match_out2in_slow;
+#define _(N, i, n, s) vec_free (ap->busy_##n##_ports_per_thread);
+      foreach_nat_protocol
+#undef _
+    }
+  vec_free (*addresses);
+  *addresses = 0;
+}
+
+int
+nat44_ei_interface_add_del (u32 sw_if_index, u8 is_inside, int is_del)
+{
+  const char *feature_name, *del_feature_name;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_interface_t *i;
+  nat44_ei_address_t *ap;
+  nat44_ei_static_mapping_t *m;
+  nat44_ei_outside_fib_t *outside_fib;
+  u32 fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4, sw_if_index);
+
+  fail_if_disabled ();
+
+  if (nm->out2in_dpo && !is_inside)
+    {
+      nat44_ei_log_err ("error unsupported");
+      return VNET_API_ERROR_UNSUPPORTED;
+    }
+
+  pool_foreach (i, nm->output_feature_interfaces)
+    {
+      if (i->sw_if_index == sw_if_index)
+	{
+	  nat44_ei_log_err ("error interface already configured");
+	  return VNET_API_ERROR_VALUE_EXIST;
+	}
     }
+
+  if (nm->static_mapping_only && !(nm->static_mapping_connection_tracking))
+    feature_name = is_inside ? "nat44-ei-in2out-fast" : "nat44-ei-out2in-fast";
   else
     {
-      sm->icmp_match_in2out_cb = icmp_match_in2out_fast;
-      sm->icmp_match_out2in_cb = icmp_match_out2in_fast;
+      if (nm->num_workers > 1)
+	feature_name = is_inside ? "nat44-ei-in2out-worker-handoff" :
+				   "nat44-ei-out2in-worker-handoff";
+      else
+	feature_name = is_inside ? "nat44-ei-in2out" : "nat44-ei-out2in";
     }
 
-  nat_reset_timeouts (&sm->timeouts);
-  nat44_ei_db_init (nm->translations, nm->translation_buckets,
-		    nm->user_buckets);
-  nat44_ei_set_alloc_default ();
-  nat_ha_enable ();
+  if (nm->fq_in2out_index == ~0 && nm->num_workers > 1)
+    nm->fq_in2out_index = vlib_frame_queue_main_init (nm->in2out_node_index,
+						      nm->frame_queue_nelts);
 
-  // TODO: function for reset counters
-  vlib_zero_simple_counter (&sm->total_users, 0);
-  vlib_zero_simple_counter (&sm->total_sessions, 0);
-  vlib_zero_simple_counter (&sm->user_limit_reached, 0);
+  if (nm->fq_out2in_index == ~0 && nm->num_workers > 1)
+    nm->fq_out2in_index = vlib_frame_queue_main_init (nm->out2in_node_index,
+						      nm->frame_queue_nelts);
 
-  if (!sm->frame_queue_nelts)
-    sm->frame_queue_nelts = NAT_FQ_NELTS_DEFAULT;
+  if (!is_inside)
+    {
+      vec_foreach (outside_fib, nm->outside_fibs)
+	{
+	  if (outside_fib->fib_index == fib_index)
+	    {
+	      if (is_del)
+		{
+		  outside_fib->refcount--;
+		  if (!outside_fib->refcount)
+		    vec_del1 (nm->outside_fibs,
+			      outside_fib - nm->outside_fibs);
+		}
+	      else
+		outside_fib->refcount++;
+	      goto feature_set;
+	    }
+	}
+      if (!is_del)
+	{
+	  vec_add2 (nm->outside_fibs, outside_fib, 1);
+	  outside_fib->refcount = 1;
+	  outside_fib->fib_index = fib_index;
+	}
+    }
 
-  sm->enabled = 1;
+feature_set:
+  pool_foreach (i, nm->interfaces)
+    {
+      if (i->sw_if_index == sw_if_index)
+	{
+	  if (is_del)
+	    {
+	      if (nat44_ei_interface_is_inside (i) &&
+		  nat44_ei_interface_is_outside (i))
+		{
+		  if (is_inside)
+		    i->flags &= ~NAT44_EI_INTERFACE_FLAG_IS_INSIDE;
+		  else
+		    i->flags &= ~NAT44_EI_INTERFACE_FLAG_IS_OUTSIDE;
+
+		  if (nm->num_workers > 1)
+		    {
+		      del_feature_name = "nat44-handoff-classify";
+		      feature_name = !is_inside ?
+				       "nat44-ei-in2out-worker-handoff" :
+				       "nat44-ei-out2in-worker-handoff";
+		    }
+		  else
+		    {
+		      del_feature_name = "nat44-ei-classify";
+		      feature_name =
+			!is_inside ? "nat44-ei-in2out" : "nat44-ei-out2in";
+		    }
+
+		  int rv =
+		    ip4_sv_reass_enable_disable_with_refcnt (sw_if_index, 0);
+		  if (rv)
+		    return rv;
+		  vnet_feature_enable_disable ("ip4-unicast", del_feature_name,
+					       sw_if_index, 0, 0, 0);
+		  vnet_feature_enable_disable ("ip4-unicast", feature_name,
+					       sw_if_index, 1, 0, 0);
+		  if (!is_inside)
+		    {
+		      vnet_feature_enable_disable ("ip4-local",
+						   "nat44-ei-hairpinning",
+						   sw_if_index, 1, 0, 0);
+		    }
+		}
+	      else
+		{
+		  int rv =
+		    ip4_sv_reass_enable_disable_with_refcnt (sw_if_index, 0);
+		  if (rv)
+		    return rv;
+		  vnet_feature_enable_disable ("ip4-unicast", feature_name,
+					       sw_if_index, 0, 0, 0);
+		  pool_put (nm->interfaces, i);
+		  if (is_inside)
+		    {
+		      vnet_feature_enable_disable ("ip4-local",
+						   "nat44-ei-hairpinning",
+						   sw_if_index, 0, 0, 0);
+		    }
+		}
+	    }
+	  else
+	    {
+	      if ((nat44_ei_interface_is_inside (i) && is_inside) ||
+		  (nat44_ei_interface_is_outside (i) && !is_inside))
+		return 0;
+
+	      if (nm->num_workers > 1)
+		{
+		  del_feature_name = !is_inside ?
+				       "nat44-ei-in2out-worker-handoff" :
+				       "nat44-ei-out2in-worker-handoff";
+		  feature_name = "nat44-handoff-classify";
+		}
+	      else
+		{
+		  del_feature_name =
+		    !is_inside ? "nat44-ei-in2out" : "nat44-ei-out2in";
+		  feature_name = "nat44-ei-classify";
+		}
+
+	      int rv =
+		ip4_sv_reass_enable_disable_with_refcnt (sw_if_index, 1);
+	      if (rv)
+		return rv;
+	      vnet_feature_enable_disable ("ip4-unicast", del_feature_name,
+					   sw_if_index, 0, 0, 0);
+	      vnet_feature_enable_disable ("ip4-unicast", feature_name,
+					   sw_if_index, 1, 0, 0);
+	      if (!is_inside)
+		{
+		  vnet_feature_enable_disable (
+		    "ip4-local", "nat44-ei-hairpinning", sw_if_index, 0, 0, 0);
+		}
+	      goto set_flags;
+	    }
+
+	  goto fib;
+	}
+    }
+
+  if (is_del)
+    {
+      nat44_ei_log_err ("error interface couldn't be found");
+      return VNET_API_ERROR_NO_SUCH_ENTRY;
+    }
+
+  pool_get (nm->interfaces, i);
+  i->sw_if_index = sw_if_index;
+  i->flags = 0;
+  nat_validate_interface_counters (nm, sw_if_index);
+
+  vnet_feature_enable_disable ("ip4-unicast", feature_name, sw_if_index, 1, 0,
+			       0);
+
+  int rv = ip4_sv_reass_enable_disable_with_refcnt (sw_if_index, 1);
+  if (rv)
+    return rv;
+
+  if (is_inside && !nm->out2in_dpo)
+    {
+      vnet_feature_enable_disable ("ip4-local", "nat44-ei-hairpinning",
+				   sw_if_index, 1, 0, 0);
+    }
+
+set_flags:
+  if (is_inside)
+    {
+      i->flags |= NAT44_EI_INTERFACE_FLAG_IS_INSIDE;
+      return 0;
+    }
+  else
+    i->flags |= NAT44_EI_INTERFACE_FLAG_IS_OUTSIDE;
+
+  /* Add/delete external addresses to FIB */
+fib:
+  vec_foreach (ap, nm->addresses)
+    nat44_ei_add_del_addr_to_fib (&ap->addr, 32, sw_if_index, !is_del);
+
+  pool_foreach (m, nm->static_mappings)
+    {
+      if (!(nat44_ei_is_addr_only_static_mapping (m)) ||
+	  (m->local_addr.as_u32 == m->external_addr.as_u32))
+	continue;
+
+      nat44_ei_add_del_addr_to_fib (&m->external_addr, 32, sw_if_index,
+				    !is_del);
+    }
+
+  return 0;
+}
+
+int
+nat44_ei_interface_add_del_output_feature (u32 sw_if_index, u8 is_inside,
+					   int is_del)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_interface_t *i;
+  nat44_ei_address_t *ap;
+  nat44_ei_static_mapping_t *m;
+  nat44_ei_outside_fib_t *outside_fib;
+  u32 fib_index =
+    fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4, sw_if_index);
+
+  fail_if_disabled ();
+
+  if (nm->static_mapping_only && !(nm->static_mapping_connection_tracking))
+    {
+      nat44_ei_log_err ("error unsupported");
+      return VNET_API_ERROR_UNSUPPORTED;
+    }
+
+  pool_foreach (i, nm->interfaces)
+    {
+      if (i->sw_if_index == sw_if_index)
+	{
+	  nat44_ei_log_err ("error interface already configured");
+	  return VNET_API_ERROR_VALUE_EXIST;
+	}
+    }
+
+  if (!is_inside)
+    {
+      vec_foreach (outside_fib, nm->outside_fibs)
+	{
+	  if (outside_fib->fib_index == fib_index)
+	    {
+	      if (is_del)
+		{
+		  outside_fib->refcount--;
+		  if (!outside_fib->refcount)
+		    vec_del1 (nm->outside_fibs,
+			      outside_fib - nm->outside_fibs);
+		}
+	      else
+		outside_fib->refcount++;
+	      goto feature_set;
+	    }
+	}
+      if (!is_del)
+	{
+	  vec_add2 (nm->outside_fibs, outside_fib, 1);
+	  outside_fib->refcount = 1;
+	  outside_fib->fib_index = fib_index;
+	}
+    }
+
+feature_set:
+  if (is_inside)
+    {
+      int rv = ip4_sv_reass_enable_disable_with_refcnt (sw_if_index, !is_del);
+      if (rv)
+	return rv;
+      rv =
+	ip4_sv_reass_output_enable_disable_with_refcnt (sw_if_index, !is_del);
+      if (rv)
+	return rv;
+      vnet_feature_enable_disable ("ip4-unicast", "nat44-ei-hairpin-dst",
+				   sw_if_index, !is_del, 0, 0);
+      vnet_feature_enable_disable ("ip4-output", "nat44-ei-hairpin-src",
+				   sw_if_index, !is_del, 0, 0);
+      goto fq;
+    }
+
+  if (nm->num_workers > 1)
+    {
+      int rv = ip4_sv_reass_enable_disable_with_refcnt (sw_if_index, !is_del);
+      if (rv)
+	return rv;
+      rv =
+	ip4_sv_reass_output_enable_disable_with_refcnt (sw_if_index, !is_del);
+      if (rv)
+	return rv;
+      vnet_feature_enable_disable ("ip4-unicast",
+				   "nat44-ei-out2in-worker-handoff",
+				   sw_if_index, !is_del, 0, 0);
+      vnet_feature_enable_disable ("ip4-output",
+				   "nat44-ei-in2out-output-worker-handoff",
+				   sw_if_index, !is_del, 0, 0);
+    }
+  else
+    {
+      int rv = ip4_sv_reass_enable_disable_with_refcnt (sw_if_index, !is_del);
+      if (rv)
+	return rv;
+      rv =
+	ip4_sv_reass_output_enable_disable_with_refcnt (sw_if_index, !is_del);
+      if (rv)
+	return rv;
+      vnet_feature_enable_disable ("ip4-unicast", "nat44-ei-out2in",
+				   sw_if_index, !is_del, 0, 0);
+      vnet_feature_enable_disable ("ip4-output", "nat44-ei-in2out-output",
+				   sw_if_index, !is_del, 0, 0);
+    }
+
+fq:
+  if (nm->fq_in2out_output_index == ~0 && nm->num_workers > 1)
+    nm->fq_in2out_output_index =
+      vlib_frame_queue_main_init (nm->in2out_output_node_index, 0);
+
+  if (nm->fq_out2in_index == ~0 && nm->num_workers > 1)
+    nm->fq_out2in_index =
+      vlib_frame_queue_main_init (nm->out2in_node_index, 0);
+
+  pool_foreach (i, nm->output_feature_interfaces)
+    {
+      if (i->sw_if_index == sw_if_index)
+	{
+	  if (is_del)
+	    pool_put (nm->output_feature_interfaces, i);
+	  else
+	    return VNET_API_ERROR_VALUE_EXIST;
+
+	  goto fib;
+	}
+    }
+
+  if (is_del)
+    {
+      nat44_ei_log_err ("error interface couldn't be found");
+      return VNET_API_ERROR_NO_SUCH_ENTRY;
+    }
+
+  pool_get (nm->output_feature_interfaces, i);
+  i->sw_if_index = sw_if_index;
+  i->flags = 0;
+  nat_validate_interface_counters (nm, sw_if_index);
+  if (is_inside)
+    i->flags |= NAT44_EI_INTERFACE_FLAG_IS_INSIDE;
+  else
+    i->flags |= NAT44_EI_INTERFACE_FLAG_IS_OUTSIDE;
+
+  /* Add/delete external addresses to FIB */
+fib:
+  if (is_inside)
+    return 0;
+
+  vec_foreach (ap, nm->addresses)
+    nat44_ei_add_del_addr_to_fib (&ap->addr, 32, sw_if_index, !is_del);
+
+  pool_foreach (m, nm->static_mappings)
+    {
+      if (!((nat44_ei_is_addr_only_static_mapping (m))) ||
+	  (m->local_addr.as_u32 == m->external_addr.as_u32))
+	continue;
+
+      nat44_ei_add_del_addr_to_fib (&m->external_addr, 32, sw_if_index,
+				    !is_del);
+    }
 
   return 0;
 }
@@ -129,81 +877,347 @@ int
 nat44_ei_plugin_disable ()
 {
   nat44_ei_main_t *nm = &nat44_ei_main;
-  snat_main_t *sm = &snat_main;
-  snat_interface_t *i, *vec;
+  nat44_ei_interface_t *i, *vec;
   int error = 0;
 
   // first unregister all nodes from interfaces
-  vec = vec_dup (sm->interfaces);
+  vec = vec_dup (nm->interfaces);
   vec_foreach (i, vec)
     {
-      if (nat_interface_is_inside (i))
-	error = snat_interface_add_del (i->sw_if_index, 1, 1);
-      if (nat_interface_is_outside (i))
-	error = snat_interface_add_del (i->sw_if_index, 0, 1);
+      if (nat44_ei_interface_is_inside (i))
+	error = nat44_ei_interface_add_del (i->sw_if_index, 1, 1);
+      if (nat44_ei_interface_is_outside (i))
+	error = nat44_ei_interface_add_del (i->sw_if_index, 0, 1);
 
       if (error)
 	{
-	  nat_log_err ("error occurred while removing interface %u",
-		       i->sw_if_index);
+	  nat44_ei_log_err ("error occurred while removing interface %u",
+			    i->sw_if_index);
 	}
     }
   vec_free (vec);
-  sm->interfaces = 0;
+  nm->interfaces = 0;
 
-  vec = vec_dup (sm->output_feature_interfaces);
+  vec = vec_dup (nm->output_feature_interfaces);
   vec_foreach (i, vec)
     {
-      if (nat_interface_is_inside (i))
-	error = snat_interface_add_del_output_feature (i->sw_if_index, 1, 1);
-      if (nat_interface_is_outside (i))
-	error = snat_interface_add_del_output_feature (i->sw_if_index, 0, 1);
+      if (nat44_ei_interface_is_inside (i))
+	error =
+	  nat44_ei_interface_add_del_output_feature (i->sw_if_index, 1, 1);
+      if (nat44_ei_interface_is_outside (i))
+	error =
+	  nat44_ei_interface_add_del_output_feature (i->sw_if_index, 0, 1);
 
       if (error)
 	{
-	  nat_log_err ("error occurred while removing interface %u",
-		       i->sw_if_index);
+	  nat44_ei_log_err ("error occurred while removing interface %u",
+			    i->sw_if_index);
 	}
     }
   vec_free (vec);
-  sm->output_feature_interfaces = 0;
+  nm->output_feature_interfaces = 0;
 
   nat_ha_disable ();
   nat44_ei_db_free ();
 
-  nat44_addresses_free (&sm->addresses);
-  nat44_addresses_free (&sm->twice_nat_addresses);
+  nat44_ei_addresses_free (&nm->addresses);
 
-  vec_free (sm->to_resolve);
-  vec_free (sm->auto_add_sw_if_indices);
-  vec_free (sm->auto_add_sw_if_indices_twice_nat);
+  vec_free (nm->to_resolve);
+  vec_free (nm->auto_add_sw_if_indices);
 
-  sm->to_resolve = 0;
-  sm->auto_add_sw_if_indices = 0;
-  sm->auto_add_sw_if_indices_twice_nat = 0;
+  nm->to_resolve = 0;
+  nm->auto_add_sw_if_indices = 0;
 
-  sm->forwarding_enabled = 0;
+  nm->forwarding_enabled = 0;
 
-  sm->enabled = 0;
+  nm->enabled = 0;
   clib_memset (&nm->rconfig, 0, sizeof (nm->rconfig));
-  clib_memset (&sm->rconfig, 0, sizeof (sm->rconfig));
 
   return error;
 }
 
+int
+nat44_ei_set_outside_address_and_port (nat44_ei_address_t *addresses,
+				       u32 thread_index, ip4_address_t addr,
+				       u16 port, nat_protocol_t protocol)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_address_t *a = 0;
+  u32 address_index;
+  u16 port_host_byte_order = clib_net_to_host_u16 (port);
+
+  for (address_index = 0; address_index < vec_len (addresses); address_index++)
+    {
+      if (addresses[address_index].addr.as_u32 != addr.as_u32)
+	continue;
+
+      a = addresses + address_index;
+      switch (protocol)
+	{
+#define _(N, j, n, s)                                                         \
+  case NAT_PROTOCOL_##N:                                                      \
+    if (a->busy_##n##_port_refcounts[port_host_byte_order])                   \
+      return VNET_API_ERROR_INSTANCE_IN_USE;                                  \
+    ++a->busy_##n##_port_refcounts[port_host_byte_order];                     \
+    a->busy_##n##_ports_per_thread[thread_index]++;                           \
+    a->busy_##n##_ports++;                                                    \
+    return 0;
+	  foreach_nat_protocol
+#undef _
+	    default : nat_elog_info (nm, "unknown protocol");
+	  return 1;
+	}
+    }
+
+  return VNET_API_ERROR_NO_SUCH_ENTRY;
+}
+
+void
+nat44_ei_add_del_address_dpo (ip4_address_t addr, u8 is_add)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  dpo_id_t dpo_v4 = DPO_INVALID;
+  fib_prefix_t pfx = {
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_len = 32,
+    .fp_addr.ip4.as_u32 = addr.as_u32,
+  };
+
+  if (is_add)
+    {
+      nat_dpo_create (DPO_PROTO_IP4, 0, &dpo_v4);
+      fib_table_entry_special_dpo_add (0, &pfx, nm->fib_src_hi,
+				       FIB_ENTRY_FLAG_EXCLUSIVE, &dpo_v4);
+      dpo_reset (&dpo_v4);
+    }
+  else
+    {
+      fib_table_entry_special_remove (0, &pfx, nm->fib_src_hi);
+    }
+}
+
+void
+nat44_ei_free_outside_address_and_port (nat44_ei_address_t *addresses,
+					u32 thread_index, ip4_address_t *addr,
+					u16 port, nat_protocol_t protocol)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_address_t *a;
+  u32 address_index;
+  u16 port_host_byte_order = clib_net_to_host_u16 (port);
+
+  for (address_index = 0; address_index < vec_len (addresses); address_index++)
+    {
+      if (addresses[address_index].addr.as_u32 == addr->as_u32)
+	break;
+    }
+
+  ASSERT (address_index < vec_len (addresses));
+
+  a = addresses + address_index;
+
+  switch (protocol)
+    {
+#define _(N, i, n, s)                                                         \
+  case NAT_PROTOCOL_##N:                                                      \
+    ASSERT (a->busy_##n##_port_refcounts[port_host_byte_order] >= 1);         \
+    --a->busy_##n##_port_refcounts[port_host_byte_order];                     \
+    a->busy_##n##_ports--;                                                    \
+    a->busy_##n##_ports_per_thread[thread_index]--;                           \
+    break;
+      foreach_nat_protocol
+#undef _
+	default : nat_elog_info (nm, "unknown protocol");
+      return;
+    }
+}
+
+void
+nat44_ei_free_session_data_v2 (nat44_ei_main_t *nm, nat44_ei_session_t *s,
+			       u32 thread_index, u8 is_ha)
+{
+  clib_bihash_kv_8_8_t kv;
+
+  /* session lookup tables */
+  init_nat_i2o_k (&kv, s);
+  if (clib_bihash_add_del_8_8 (&nm->in2out, &kv, 0))
+    nat_elog_warn (nm, "in2out key del failed");
+  init_nat_o2i_k (&kv, s);
+  if (clib_bihash_add_del_8_8 (&nm->out2in, &kv, 0))
+    nat_elog_warn (nm, "out2in key del failed");
+
+  if (!is_ha)
+    nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
+			     &s->in2out.addr, s->in2out.port, &s->out2in.addr,
+			     s->out2in.port, s->nat_proto);
+
+  if (nat44_ei_is_unk_proto_session (s))
+    return;
+
+  if (!is_ha)
+    {
+      /* log NAT event */
+      nat_ipfix_logging_nat44_ses_delete (
+	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_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
+		   s->ext_host_port, s->nat_proto, s->out2in.fib_index,
+		   thread_index);
+    }
+
+  if (nat44_ei_is_session_static (s))
+    return;
+
+  nat44_ei_free_outside_address_and_port (nm->addresses, thread_index,
+					  &s->out2in.addr, s->out2in.port,
+					  s->nat_proto);
+}
+
+nat44_ei_user_t *
+nat44_ei_user_get_or_create (nat44_ei_main_t *nm, ip4_address_t *addr,
+			     u32 fib_index, u32 thread_index)
+{
+  nat44_ei_user_t *u = 0;
+  nat44_ei_user_key_t user_key;
+  clib_bihash_kv_8_8_t kv, value;
+  nat44_ei_main_per_thread_data_t *tnm = &nm->per_thread_data[thread_index];
+  dlist_elt_t *per_user_list_head_elt;
+
+  user_key.addr.as_u32 = addr->as_u32;
+  user_key.fib_index = fib_index;
+  kv.key = user_key.as_u64;
+
+  /* Ever heard of the "user" = src ip4 address before? */
+  if (clib_bihash_search_8_8 (&tnm->user_hash, &kv, &value))
+    {
+      if (pool_elts (tnm->users) >= nm->max_users_per_thread)
+	{
+	  vlib_increment_simple_counter (&nm->user_limit_reached, thread_index,
+					 0, 1);
+	  nat_elog_warn (nm, "maximum user limit reached");
+	  return NULL;
+	}
+      /* no, make a new one */
+      pool_get (tnm->users, u);
+      clib_memset (u, 0, sizeof (*u));
+
+      u->addr.as_u32 = addr->as_u32;
+      u->fib_index = fib_index;
+
+      pool_get (tnm->list_pool, per_user_list_head_elt);
+
+      u->sessions_per_user_list_head_index =
+	per_user_list_head_elt - tnm->list_pool;
+
+      clib_dlist_init (tnm->list_pool, u->sessions_per_user_list_head_index);
+
+      kv.value = u - tnm->users;
+
+      /* add user */
+      if (clib_bihash_add_del_8_8 (&tnm->user_hash, &kv, 1))
+	{
+	  nat_elog_warn (nm, "user_hash key add failed");
+	  nat44_ei_delete_user_with_no_session (nm, u, thread_index);
+	  return NULL;
+	}
+
+      vlib_set_simple_counter (&nm->total_users, thread_index, 0,
+			       pool_elts (tnm->users));
+    }
+  else
+    {
+      u = pool_elt_at_index (tnm->users, value.value);
+    }
+
+  return u;
+}
+
+nat44_ei_session_t *
+nat44_ei_session_alloc_or_recycle (nat44_ei_main_t *nm, nat44_ei_user_t *u,
+				   u32 thread_index, f64 now)
+{
+  nat44_ei_session_t *s;
+  nat44_ei_main_per_thread_data_t *tnm = &nm->per_thread_data[thread_index];
+  u32 oldest_per_user_translation_list_index, session_index;
+  dlist_elt_t *oldest_per_user_translation_list_elt;
+  dlist_elt_t *per_user_translation_list_elt;
+
+  /* Over quota? Recycle the least recently used translation */
+  if ((u->nsessions + u->nstaticsessions) >= nm->max_translations_per_user)
+    {
+      oldest_per_user_translation_list_index = clib_dlist_remove_head (
+	tnm->list_pool, u->sessions_per_user_list_head_index);
+
+      ASSERT (oldest_per_user_translation_list_index != ~0);
+
+      /* Add it back to the end of the LRU list */
+      clib_dlist_addtail (tnm->list_pool, u->sessions_per_user_list_head_index,
+			  oldest_per_user_translation_list_index);
+      /* Get the list element */
+      oldest_per_user_translation_list_elt = pool_elt_at_index (
+	tnm->list_pool, oldest_per_user_translation_list_index);
+
+      /* Get the session index from the list element */
+      session_index = oldest_per_user_translation_list_elt->value;
+
+      /* Get the session */
+      s = pool_elt_at_index (tnm->sessions, session_index);
+
+      nat44_ei_free_session_data_v2 (nm, s, thread_index, 0);
+      if (nat44_ei_is_session_static (s))
+	u->nstaticsessions--;
+      else
+	u->nsessions--;
+      s->flags = 0;
+      s->total_bytes = 0;
+      s->total_pkts = 0;
+      s->state = 0;
+      s->ext_host_addr.as_u32 = 0;
+      s->ext_host_port = 0;
+      s->ext_host_nat_addr.as_u32 = 0;
+      s->ext_host_nat_port = 0;
+    }
+  else
+    {
+      pool_get (tnm->sessions, s);
+      clib_memset (s, 0, sizeof (*s));
+
+      /* Create list elts */
+      pool_get (tnm->list_pool, per_user_translation_list_elt);
+      clib_dlist_init (tnm->list_pool,
+		       per_user_translation_list_elt - tnm->list_pool);
+
+      per_user_translation_list_elt->value = s - tnm->sessions;
+      s->per_user_index = per_user_translation_list_elt - tnm->list_pool;
+      s->per_user_list_head_index = u->sessions_per_user_list_head_index;
+
+      clib_dlist_addtail (tnm->list_pool, s->per_user_list_head_index,
+			  per_user_translation_list_elt - tnm->list_pool);
+
+      s->user_index = u - tnm->users;
+      vlib_set_simple_counter (&nm->total_sessions, thread_index, 0,
+			       pool_elts (tnm->sessions));
+    }
+
+  s->ha_last_refreshed = now;
+
+  return s;
+}
+
 void
-nat44_ei_free_session_data (snat_main_t *sm, snat_session_t *s,
+nat44_ei_free_session_data (nat44_ei_main_t *nm, nat44_ei_session_t *s,
 			    u32 thread_index, u8 is_ha)
 {
   clib_bihash_kv_8_8_t kv;
 
   init_nat_i2o_k (&kv, s);
-  if (clib_bihash_add_del_8_8 (&sm->in2out, &kv, 0))
-    nat_elog_warn ("in2out key del failed");
+  if (clib_bihash_add_del_8_8 (&nm->in2out, &kv, 0))
+    nat_elog_warn (nm, "in2out key del failed");
 
   init_nat_o2i_k (&kv, s);
-  if (clib_bihash_add_del_8_8 (&sm->out2in, &kv, 0))
-    nat_elog_warn ("out2in key del failed");
+  if (clib_bihash_add_del_8_8 (&nm->out2in, &kv, 0))
+    nat_elog_warn (nm, "out2in key del failed");
 
   if (!is_ha)
     {
@@ -220,36 +1234,36 @@ nat44_ei_free_session_data (snat_main_t *sm, snat_session_t *s,
 		   thread_index);
     }
 
-  if (snat_is_session_static (s))
+  if (nat44_ei_is_session_static (s))
     return;
 
-  snat_free_outside_address_and_port (sm->addresses, thread_index,
-				      &s->out2in.addr, s->out2in.port,
-				      s->nat_proto);
+  nat44_ei_free_outside_address_and_port (nm->addresses, thread_index,
+					  &s->out2in.addr, s->out2in.port,
+					  s->nat_proto);
 }
 
 static_always_inline void
-nat44_ei_user_del_sessions (snat_user_t *u, u32 thread_index)
+nat44_ei_user_del_sessions (nat44_ei_user_t *u, u32 thread_index)
 {
   dlist_elt_t *elt;
-  snat_session_t *s;
+  nat44_ei_session_t *s;
 
-  snat_main_t *sm = &snat_main;
-  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];
 
   // get head
   elt =
-    pool_elt_at_index (tsm->list_pool, u->sessions_per_user_list_head_index);
+    pool_elt_at_index (tnm->list_pool, u->sessions_per_user_list_head_index);
   // get first element
-  elt = pool_elt_at_index (tsm->list_pool, elt->next);
+  elt = pool_elt_at_index (tnm->list_pool, elt->next);
 
   while (elt->value != ~0)
     {
-      s = pool_elt_at_index (tsm->sessions, elt->value);
-      elt = pool_elt_at_index (tsm->list_pool, elt->next);
+      s = pool_elt_at_index (tnm->sessions, elt->value);
+      elt = pool_elt_at_index (tnm->list_pool, elt->next);
 
-      nat44_ei_free_session_data (sm, s, thread_index, 0);
-      nat44_delete_session (sm, s, thread_index);
+      nat44_ei_free_session_data (nm, s, thread_index, 0);
+      nat44_ei_delete_session (nm, s, thread_index);
     }
 }
 
@@ -258,28 +1272,25 @@ nat44_ei_user_del (ip4_address_t *addr, u32 fib_index)
 {
   int rv = 1;
 
-  snat_main_t *sm = &snat_main;
-  snat_main_per_thread_data_t *tsm;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_main_per_thread_data_t *tnm;
 
-  snat_user_key_t user_key;
+  nat44_ei_user_key_t user_key;
   clib_bihash_kv_8_8_t kv, value;
 
-  if (sm->endpoint_dependent)
-    return rv;
-
   user_key.addr.as_u32 = addr->as_u32;
   user_key.fib_index = fib_index;
   kv.key = user_key.as_u64;
 
-  if (sm->num_workers > 1)
+  if (nm->num_workers > 1)
     {
-      vec_foreach (tsm, sm->per_thread_data)
+      vec_foreach (tnm, nm->per_thread_data)
 	{
-	  if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
+	  if (!clib_bihash_search_8_8 (&tnm->user_hash, &kv, &value))
 	    {
 	      nat44_ei_user_del_sessions (
-		pool_elt_at_index (tsm->users, value.value),
-		tsm->thread_index);
+		pool_elt_at_index (tnm->users, value.value),
+		tnm->thread_index);
 	      rv = 0;
 	      break;
 	    }
@@ -287,11 +1298,11 @@ nat44_ei_user_del (ip4_address_t *addr, u32 fib_index)
     }
   else
     {
-      tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
-      if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
+      tnm = vec_elt_at_index (nm->per_thread_data, nm->num_workers);
+      if (!clib_bihash_search_8_8 (&tnm->user_hash, &kv, &value))
 	{
 	  nat44_ei_user_del_sessions (
-	    pool_elt_at_index (tsm->users, value.value), tsm->thread_index);
+	    pool_elt_at_index (tnm->users, value.value), tnm->thread_index);
 	  rv = 0;
 	}
     }
@@ -299,34 +1310,34 @@ nat44_ei_user_del (ip4_address_t *addr, u32 fib_index)
 }
 
 void
-nat44_ei_static_mapping_del_sessions (snat_main_t *sm,
-				      snat_main_per_thread_data_t *tsm,
-				      snat_user_key_t u_key, int addr_only,
+nat44_ei_static_mapping_del_sessions (nat44_ei_main_t *nm,
+				      nat44_ei_main_per_thread_data_t *tnm,
+				      nat44_ei_user_key_t u_key, int addr_only,
 				      ip4_address_t e_addr, u16 e_port)
 {
   clib_bihash_kv_8_8_t kv, value;
   kv.key = u_key.as_u64;
   u64 user_index;
   dlist_elt_t *head, *elt;
-  snat_user_t *u;
-  snat_session_t *s;
+  nat44_ei_user_t *u;
+  nat44_ei_session_t *s;
   u32 elt_index, head_index, ses_index;
 
-  if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
+  if (!clib_bihash_search_8_8 (&tnm->user_hash, &kv, &value))
     {
       user_index = value.value;
-      u = pool_elt_at_index (tsm->users, user_index);
+      u = pool_elt_at_index (tnm->users, user_index);
       if (u->nstaticsessions)
 	{
 	  head_index = u->sessions_per_user_list_head_index;
-	  head = pool_elt_at_index (tsm->list_pool, head_index);
+	  head = pool_elt_at_index (tnm->list_pool, head_index);
 	  elt_index = head->next;
-	  elt = pool_elt_at_index (tsm->list_pool, elt_index);
+	  elt = pool_elt_at_index (tnm->list_pool, elt_index);
 	  ses_index = elt->value;
 	  while (ses_index != ~0)
 	    {
-	      s = pool_elt_at_index (tsm->sessions, ses_index);
-	      elt = pool_elt_at_index (tsm->list_pool, elt->next);
+	      s = pool_elt_at_index (tnm->sessions, ses_index);
+	      elt = pool_elt_at_index (tnm->list_pool, elt->next);
 	      ses_index = elt->value;
 
 	      if (!addr_only)
@@ -336,14 +1347,12 @@ nat44_ei_static_mapping_del_sessions (snat_main_t *sm,
 		    continue;
 		}
 
-	      if (is_lb_session (s))
+	      if (!nat44_ei_is_session_static (s))
 		continue;
 
-	      if (!snat_is_session_static (s))
-		continue;
-
-	      nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
-	      nat44_delete_session (sm, s, tsm - sm->per_thread_data);
+	      nat44_ei_free_session_data_v2 (nm, s, tnm - nm->per_thread_data,
+					     0);
+	      nat44_ei_delete_session (nm, s, tnm - nm->per_thread_data);
 
 	      if (!addr_only)
 		break;
@@ -356,18 +1365,18 @@ u32
 nat44_ei_get_in2out_worker_index (ip4_header_t *ip0, u32 rx_fib_index0,
 				  u8 is_output)
 {
-  snat_main_t *sm = &snat_main;
+  nat44_ei_main_t *nm = &nat44_ei_main;
   u32 next_worker_index = 0;
   u32 hash;
 
-  next_worker_index = sm->first_worker_index;
+  next_worker_index = nm->first_worker_index;
   hash = ip0->src_address.as_u32 + (ip0->src_address.as_u32 >> 8) +
 	 (ip0->src_address.as_u32 >> 16) + (ip0->src_address.as_u32 >> 24);
 
-  if (PREDICT_TRUE (is_pow2 (_vec_len (sm->workers))))
-    next_worker_index += sm->workers[hash & (_vec_len (sm->workers) - 1)];
+  if (PREDICT_TRUE (is_pow2 (_vec_len (nm->workers))))
+    next_worker_index += nm->workers[hash & (_vec_len (nm->workers) - 1)];
   else
-    next_worker_index += sm->workers[hash % _vec_len (sm->workers)];
+    next_worker_index += nm->workers[hash % _vec_len (nm->workers)];
 
   return next_worker_index;
 }
@@ -376,22 +1385,22 @@ u32
 nat44_ei_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip0,
 				  u32 rx_fib_index0, u8 is_output)
 {
-  snat_main_t *sm = &snat_main;
+  nat44_ei_main_t *nm = &nat44_ei_main;
   udp_header_t *udp;
   u16 port;
   clib_bihash_kv_8_8_t kv, value;
-  snat_static_mapping_t *m;
+  nat44_ei_static_mapping_t *m;
   u32 proto;
   u32 next_worker_index = 0;
 
   /* first try static mappings without port */
-  if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
+  if (PREDICT_FALSE (pool_elts (nm->static_mappings)))
     {
       init_nat_k (&kv, ip0->dst_address, 0, rx_fib_index0, 0);
-      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv,
+      if (!clib_bihash_search_8_8 (&nm->static_mapping_by_external, &kv,
 				   &value))
 	{
-	  m = pool_elt_at_index (sm->static_mappings, value.value);
+	  m = pool_elt_at_index (nm->static_mappings, value.value);
 	  return m->workers[0];
 	}
     }
@@ -438,33 +1447,34 @@ nat44_ei_get_out2in_worker_index (vlib_buffer_t *b, ip4_header_t *ip0,
     }
 
   /* try static mappings with port */
-  if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
+  if (PREDICT_FALSE (pool_elts (nm->static_mappings)))
     {
       init_nat_k (&kv, ip0->dst_address, port, rx_fib_index0, proto);
-      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv,
+      if (!clib_bihash_search_8_8 (&nm->static_mapping_by_external, &kv,
 				   &value))
 	{
-	  m = pool_elt_at_index (sm->static_mappings, value.value);
+	  m = pool_elt_at_index (nm->static_mappings, value.value);
 	  return m->workers[0];
 	}
     }
 
   /* worker by outside port */
-  next_worker_index = sm->first_worker_index;
+  next_worker_index = nm->first_worker_index;
   next_worker_index +=
-    sm->workers[(clib_net_to_host_u16 (port) - 1024) / sm->port_per_thread];
+    nm->workers[(clib_net_to_host_u16 (port) - 1024) / nm->port_per_thread];
   return next_worker_index;
 }
 
 static int
-nat44_ei_alloc_default_cb (snat_address_t *addresses, u32 fib_index,
+nat44_ei_alloc_default_cb (nat44_ei_address_t *addresses, u32 fib_index,
 			   u32 thread_index, nat_protocol_t proto,
 			   ip4_address_t *addr, u16 *port, u16 port_per_thread,
 			   u32 snat_thread_index)
 {
-  int i;
-  snat_address_t *a, *ga = 0;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_address_t *a, *ga = 0;
   u32 portnum;
+  int i;
 
   for (i = 0; i < vec_len (addresses); i++)
     {
@@ -480,7 +1490,9 @@ nat44_ei_alloc_default_cb (snat_address_t *addresses, u32 fib_index,
 	    while (1)                                                         \
 	      {                                                               \
 		portnum = (port_per_thread * snat_thread_index) +             \
-			  snat_random_port (0, port_per_thread - 1) + 1024;   \
+			  nat_random_port (&nm->random_seed, 0,               \
+					   port_per_thread - 1) +             \
+			  1024;                                               \
 		if (a->busy_##n##_port_refcounts[portnum])                    \
 		  continue;                                                   \
 		--a->busy_##n##_port_refcounts[portnum];                      \
@@ -499,7 +1511,7 @@ nat44_ei_alloc_default_cb (snat_address_t *addresses, u32 fib_index,
     break;
 	  foreach_nat_protocol
 #undef _
-	    default : nat_elog_info ("unknown protocol");
+	    default : nat_elog_info (nm, "unknown protocol");
 	  return 1;
 	}
     }
@@ -513,8 +1525,9 @@ nat44_ei_alloc_default_cb (snat_address_t *addresses, u32 fib_index,
   case NAT_PROTOCOL_##N:                                                      \
     while (1)                                                                 \
       {                                                                       \
-	portnum = (port_per_thread * snat_thread_index) +                     \
-		  snat_random_port (0, port_per_thread - 1) + 1024;           \
+	portnum =                                                             \
+	  (port_per_thread * snat_thread_index) +                             \
+	  nat_random_port (&nm->random_seed, 0, port_per_thread - 1) + 1024;  \
 	if (a->busy_##n##_port_refcounts[portnum])                            \
 	  continue;                                                           \
 	++a->busy_##n##_port_refcounts[portnum];                              \
@@ -527,7 +1540,7 @@ nat44_ei_alloc_default_cb (snat_address_t *addresses, u32 fib_index,
 	  break;
 	  foreach_nat_protocol
 #undef _
-	    default : nat_elog_info ("unknown protocol");
+	    default : nat_elog_info (nm, "unknown protocol");
 	  return 1;
 	}
     }
@@ -538,16 +1551,16 @@ nat44_ei_alloc_default_cb (snat_address_t *addresses, u32 fib_index,
 }
 
 static int
-nat44_ei_alloc_range_cb (snat_address_t *addresses, u32 fib_index,
+nat44_ei_alloc_range_cb (nat44_ei_address_t *addresses, u32 fib_index,
 			 u32 thread_index, nat_protocol_t proto,
 			 ip4_address_t *addr, u16 *port, u16 port_per_thread,
 			 u32 snat_thread_index)
 {
-  snat_main_t *sm = &snat_main;
-  snat_address_t *a = addresses;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_address_t *a = addresses;
   u16 portnum, ports;
 
-  ports = sm->end_port - sm->start_port + 1;
+  ports = nm->end_port - nm->start_port + 1;
 
   if (!vec_len (addresses))
     goto exhausted;
@@ -560,7 +1573,8 @@ nat44_ei_alloc_range_cb (snat_address_t *addresses, u32 fib_index,
       {                                                                       \
 	while (1)                                                             \
 	  {                                                                   \
-	    portnum = snat_random_port (sm->start_port, sm->end_port);        \
+	    portnum = nat_random_port (&nm->random_seed, nm->start_port,      \
+				       nm->end_port);                         \
 	    if (a->busy_##n##_port_refcounts[portnum])                        \
 	      continue;                                                       \
 	    ++a->busy_##n##_port_refcounts[portnum];                          \
@@ -573,7 +1587,7 @@ nat44_ei_alloc_range_cb (snat_address_t *addresses, u32 fib_index,
     break;
       foreach_nat_protocol
 #undef _
-	default : nat_elog_info ("unknown protocol");
+	default : nat_elog_info (nm, "unknown protocol");
       return 1;
     }
 
@@ -584,16 +1598,16 @@ exhausted:
 }
 
 static int
-nat44_ei_alloc_mape_cb (snat_address_t *addresses, u32 fib_index,
+nat44_ei_alloc_mape_cb (nat44_ei_address_t *addresses, u32 fib_index,
 			u32 thread_index, nat_protocol_t proto,
 			ip4_address_t *addr, u16 *port, u16 port_per_thread,
 			u32 snat_thread_index)
 {
-  snat_main_t *sm = &snat_main;
-  snat_address_t *a = addresses;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_address_t *a = addresses;
   u16 m, ports, portnum, A, j;
-  m = 16 - (sm->psid_offset + sm->psid_length);
-  ports = (1 << (16 - sm->psid_length)) - (1 << m);
+  m = 16 - (nm->psid_offset + nm->psid_length);
+  ports = (1 << (16 - nm->psid_length)) - (1 << m);
 
   if (!vec_len (addresses))
     goto exhausted;
@@ -606,9 +1620,10 @@ nat44_ei_alloc_mape_cb (snat_address_t *addresses, u32 fib_index,
       {                                                                       \
 	while (1)                                                             \
 	  {                                                                   \
-	    A = snat_random_port (1, pow2_mask (sm->psid_offset));            \
-	    j = snat_random_port (0, pow2_mask (m));                          \
-	    portnum = A | (sm->psid << sm->psid_offset) | (j << (16 - m));    \
+	    A = nat_random_port (&nm->random_seed, 1,                         \
+				 pow2_mask (nm->psid_offset));                \
+	    j = nat_random_port (&nm->random_seed, 0, pow2_mask (m));         \
+	    portnum = A | (nm->psid << nm->psid_offset) | (j << (16 - m));    \
 	    if (a->busy_##n##_port_refcounts[portnum])                        \
 	      continue;                                                       \
 	    ++a->busy_##n##_port_refcounts[portnum];                          \
@@ -621,7 +1636,7 @@ nat44_ei_alloc_mape_cb (snat_address_t *addresses, u32 fib_index,
     break;
       foreach_nat_protocol
 #undef _
-	default : nat_elog_info ("unknown protocol");
+	default : nat_elog_info (nm, "unknown protocol");
       return 1;
     }
 
@@ -634,33 +1649,33 @@ exhausted:
 void
 nat44_ei_set_alloc_default ()
 {
-  snat_main_t *sm = &snat_main;
+  nat44_ei_main_t *nm = &nat44_ei_main;
 
-  sm->addr_and_port_alloc_alg = NAT_ADDR_AND_PORT_ALLOC_ALG_DEFAULT;
-  sm->alloc_addr_and_port = nat44_ei_alloc_default_cb;
+  nm->addr_and_port_alloc_alg = NAT44_EI_ADDR_AND_PORT_ALLOC_ALG_DEFAULT;
+  nm->alloc_addr_and_port = nat44_ei_alloc_default_cb;
 }
 
 void
 nat44_ei_set_alloc_range (u16 start_port, u16 end_port)
 {
-  snat_main_t *sm = &snat_main;
+  nat44_ei_main_t *nm = &nat44_ei_main;
 
-  sm->addr_and_port_alloc_alg = NAT_ADDR_AND_PORT_ALLOC_ALG_RANGE;
-  sm->alloc_addr_and_port = nat44_ei_alloc_range_cb;
-  sm->start_port = start_port;
-  sm->end_port = end_port;
+  nm->addr_and_port_alloc_alg = NAT44_EI_ADDR_AND_PORT_ALLOC_ALG_RANGE;
+  nm->alloc_addr_and_port = nat44_ei_alloc_range_cb;
+  nm->start_port = start_port;
+  nm->end_port = end_port;
 }
 
 void
 nat44_ei_set_alloc_mape (u16 psid, u16 psid_offset, u16 psid_length)
 {
-  snat_main_t *sm = &snat_main;
+  nat44_ei_main_t *nm = &nat44_ei_main;
 
-  sm->addr_and_port_alloc_alg = NAT_ADDR_AND_PORT_ALLOC_ALG_MAPE;
-  sm->alloc_addr_and_port = nat44_ei_alloc_mape_cb;
-  sm->psid = psid;
-  sm->psid_offset = psid_offset;
-  sm->psid_length = psid_length;
+  nm->addr_and_port_alloc_alg = NAT44_EI_ADDR_AND_PORT_ALLOC_ALG_MAPE;
+  nm->alloc_addr_and_port = nat44_ei_alloc_mape_cb;
+  nm->psid = psid;
+  nm->psid_offset = psid_offset;
+  nm->psid_length = psid_length;
 }
 
 static void
@@ -670,10 +1685,10 @@ nat44_ei_add_static_mapping_when_resolved (ip4_address_t l_addr, u16 l_port,
 					   int addr_only, int identity_nat,
 					   u8 *tag)
 {
-  snat_main_t *sm = &snat_main;
-  snat_static_map_resolve_t *rp;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_static_map_resolve_t *rp;
 
-  vec_add2 (sm->to_resolve, rp, 1);
+  vec_add2 (nm->to_resolve, rp, 1);
   clib_memset (rp, 0, sizeof (*rp));
 
   rp->l_addr.as_u32 = l_addr.as_u32;
@@ -687,65 +1702,131 @@ nat44_ei_add_static_mapping_when_resolved (ip4_address_t l_addr, u16 l_port,
   rp->tag = vec_dup (tag);
 }
 
+void
+nat44_ei_delete_session (nat44_ei_main_t *nm, nat44_ei_session_t *ses,
+			 u32 thread_index)
+{
+  nat44_ei_main_per_thread_data_t *tnm =
+    vec_elt_at_index (nm->per_thread_data, thread_index);
+  clib_bihash_kv_8_8_t kv, value;
+  nat44_ei_user_t *u;
+  const nat44_ei_user_key_t u_key = { .addr = ses->in2out.addr,
+				      .fib_index = ses->in2out.fib_index };
+  const u8 u_static = nat44_ei_is_session_static (ses);
+
+  clib_dlist_remove (tnm->list_pool, ses->per_user_index);
+  pool_put_index (tnm->list_pool, ses->per_user_index);
+
+  pool_put (tnm->sessions, ses);
+  vlib_set_simple_counter (&nm->total_sessions, thread_index, 0,
+			   pool_elts (tnm->sessions));
+
+  kv.key = u_key.as_u64;
+  if (!clib_bihash_search_8_8 (&tnm->user_hash, &kv, &value))
+    {
+      u = pool_elt_at_index (tnm->users, value.value);
+      if (u_static)
+	u->nstaticsessions--;
+      else
+	u->nsessions--;
+
+      nat44_ei_delete_user_with_no_session (nm, u, thread_index);
+    }
+}
+
 int
-nat44_ei_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
+nat44_ei_del_session (nat44_ei_main_t *nm, ip4_address_t *addr, u16 port,
 		      nat_protocol_t proto, u32 vrf_id, int is_in)
 {
-  snat_main_per_thread_data_t *tsm;
+  nat44_ei_main_per_thread_data_t *tnm;
   clib_bihash_kv_8_8_t kv, value;
   ip4_header_t ip;
   u32 fib_index = fib_table_find (FIB_PROTOCOL_IP4, vrf_id);
-  snat_session_t *s;
+  nat44_ei_session_t *s;
   clib_bihash_8_8_t *t;
 
-  if (sm->endpoint_dependent)
-    return VNET_API_ERROR_UNSUPPORTED;
-
   ip.dst_address.as_u32 = ip.src_address.as_u32 = addr->as_u32;
-  if (sm->num_workers > 1)
-    tsm = vec_elt_at_index (sm->per_thread_data,
-			    sm->worker_in2out_cb (&ip, fib_index, 0));
+  if (nm->num_workers > 1)
+    tnm = vec_elt_at_index (nm->per_thread_data,
+			    nm->worker_in2out_cb (&ip, fib_index, 0));
   else
-    tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
+    tnm = vec_elt_at_index (nm->per_thread_data, nm->num_workers);
 
   init_nat_k (&kv, *addr, port, fib_index, proto);
-  t = is_in ? &sm->in2out : &sm->out2in;
+  t = is_in ? &nm->in2out : &nm->out2in;
   if (!clib_bihash_search_8_8 (t, &kv, &value))
     {
-      if (pool_is_free_index (tsm->sessions, value.value))
+      if (pool_is_free_index (tnm->sessions, value.value))
 	return VNET_API_ERROR_UNSPECIFIED;
 
-      s = pool_elt_at_index (tsm->sessions, value.value);
-      nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
-      nat44_delete_session (sm, s, tsm - sm->per_thread_data);
+      s = pool_elt_at_index (tnm->sessions, value.value);
+      nat44_ei_free_session_data_v2 (nm, s, tnm - nm->per_thread_data, 0);
+      nat44_ei_delete_session (nm, s, tnm - nm->per_thread_data);
       return 0;
     }
 
   return VNET_API_ERROR_NO_SUCH_ENTRY;
 }
 
+u32
+nat44_ei_get_thread_idx_by_port (u16 e_port)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  u32 thread_idx = nm->num_workers;
+  if (nm->num_workers > 1)
+    {
+      thread_idx = nm->first_worker_index +
+		   nm->workers[(e_port - 1024) / nm->port_per_thread];
+    }
+  return thread_idx;
+}
+
+void
+nat44_ei_add_del_addr_to_fib (ip4_address_t *addr, u8 p_len, u32 sw_if_index,
+			      int is_add)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  fib_prefix_t prefix = {
+    .fp_len = p_len,
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_addr = {
+		.ip4.as_u32 = addr->as_u32,
+		},
+  };
+  u32 fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
+
+  if (is_add)
+    fib_table_entry_update_one_path (
+      fib_index, &prefix, nm->fib_src_low,
+      (FIB_ENTRY_FLAG_CONNECTED | FIB_ENTRY_FLAG_LOCAL |
+       FIB_ENTRY_FLAG_EXCLUSIVE),
+      DPO_PROTO_IP4, NULL, sw_if_index, ~0, 1, NULL, FIB_ROUTE_PATH_FLAG_NONE);
+  else
+    fib_table_entry_delete (fib_index, &prefix, nm->fib_src_low);
+}
+
 int
 nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 				 u16 l_port, u16 e_port, nat_protocol_t proto,
 				 u32 sw_if_index, u32 vrf_id, u8 addr_only,
 				 u8 identity_nat, u8 *tag, u8 is_add)
 {
-  snat_main_t *sm = &snat_main;
-  snat_static_mapping_t *m = 0;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_static_mapping_t *m = 0;
   clib_bihash_kv_8_8_t kv, value;
-  snat_address_t *a = 0;
+  nat44_ei_address_t *a = 0;
   u32 fib_index = ~0;
-  snat_interface_t *interface;
-  snat_main_per_thread_data_t *tsm;
-  snat_user_key_t u_key;
-  snat_user_t *u;
+  nat44_ei_interface_t *interface;
+  nat44_ei_main_per_thread_data_t *tnm;
+  nat44_ei_user_key_t u_key;
+  nat44_ei_user_t *u;
   dlist_elt_t *head, *elt;
   u32 elt_index, head_index;
   u32 ses_index;
   u64 user_index;
-  snat_session_t *s;
-  snat_static_map_resolve_t *rp, *rp_match = 0;
-  nat44_lb_addr_port_t *local;
+  nat44_ei_session_t *s;
+  nat44_ei_static_map_resolve_t *rp, *rp_match = 0;
+  nat44_ei_lb_addr_port_t *local;
   u32 find = ~0;
   int i;
 
@@ -753,9 +1834,9 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
     {
       ip4_address_t *first_int_addr;
 
-      for (i = 0; i < vec_len (sm->to_resolve); i++)
+      for (i = 0; i < vec_len (nm->to_resolve); i++)
 	{
-	  rp = sm->to_resolve + i;
+	  rp = nm->to_resolve + i;
 	  if (rp->sw_if_index != sw_if_index ||
 	      rp->l_addr.as_u32 != l_addr.as_u32 || rp->vrf_id != vrf_id ||
 	      rp->addr_only != addr_only)
@@ -774,7 +1855,7 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
       /* Might be already set... */
       first_int_addr = ip4_interface_first_address (
-	sm->ip4_main, sw_if_index, 0 /* just want the address */);
+	nm->ip4_main, sw_if_index, 0 /* just want the address */);
 
       if (is_add)
 	{
@@ -799,7 +1880,7 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 	  if (!rp_match)
 	    return VNET_API_ERROR_NO_SUCH_ENTRY;
 
-	  vec_del1 (sm->to_resolve, i);
+	  vec_del1 (nm->to_resolve, i);
 
 	  if (!first_int_addr)
 	    return 0;
@@ -812,15 +1893,15 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
     }
 
   init_nat_k (&kv, e_addr, addr_only ? 0 : e_port, 0, addr_only ? 0 : proto);
-  if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
-    m = pool_elt_at_index (sm->static_mappings, value.value);
+  if (!clib_bihash_search_8_8 (&nm->static_mapping_by_external, &kv, &value))
+    m = pool_elt_at_index (nm->static_mappings, value.value);
 
   if (is_add)
     {
       if (m)
 	{
 	  // identity mapping for second vrf
-	  if (is_identity_static_mapping (m))
+	  if (nat44_ei_is_identity_static_mapping (m))
 	    {
 	      pool_foreach (local, m->locals)
 		{
@@ -830,10 +1911,10 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 	      pool_get (m->locals, local);
 	      local->vrf_id = vrf_id;
 	      local->fib_index = fib_table_find_or_create_and_lock (
-		FIB_PROTOCOL_IP4, vrf_id, sm->fib_src_low);
+		FIB_PROTOCOL_IP4, vrf_id, nm->fib_src_low);
 	      init_nat_kv (&kv, m->local_addr, m->local_port, local->fib_index,
-			   m->proto, 0, m - sm->static_mappings);
-	      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
+			   m->proto, 0, m - nm->static_mappings);
+	      clib_bihash_add_del_8_8 (&nm->static_mapping_by_local, &kv, 1);
 	      return 0;
 	    }
 	  return VNET_API_ERROR_VALUE_EXIST;
@@ -843,34 +1924,34 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       if (vrf_id != ~0)
 	{
 	  fib_index = fib_table_find_or_create_and_lock (
-	    FIB_PROTOCOL_IP4, vrf_id, sm->fib_src_low);
+	    FIB_PROTOCOL_IP4, vrf_id, nm->fib_src_low);
 	}
       /* If not specified use inside VRF id from NAT44 plugin config */
       else
 	{
-	  fib_index = sm->inside_fib_index;
-	  vrf_id = sm->inside_vrf_id;
-	  fib_table_lock (fib_index, FIB_PROTOCOL_IP4, sm->fib_src_low);
+	  fib_index = nm->inside_fib_index;
+	  vrf_id = nm->inside_vrf_id;
+	  fib_table_lock (fib_index, FIB_PROTOCOL_IP4, nm->fib_src_low);
 	}
 
       if (!identity_nat)
 	{
 	  init_nat_k (&kv, l_addr, addr_only ? 0 : l_port, fib_index,
 		      addr_only ? 0 : proto);
-	  if (!clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv,
+	  if (!clib_bihash_search_8_8 (&nm->static_mapping_by_local, &kv,
 				       &value))
 	    return VNET_API_ERROR_VALUE_EXIST;
 	}
 
       /* Find external address in allocated addresses and reserve port for
 	 address and port pair mapping when dynamic translations enabled */
-      if (!(addr_only || sm->static_mapping_only))
+      if (!(addr_only || nm->static_mapping_only))
 	{
-	  for (i = 0; i < vec_len (sm->addresses); i++)
+	  for (i = 0; i < vec_len (nm->addresses); i++)
 	    {
-	      if (sm->addresses[i].addr.as_u32 == e_addr.as_u32)
+	      if (nm->addresses[i].addr.as_u32 == e_addr.as_u32)
 		{
-		  a = sm->addresses + i;
+		  a = nm->addresses + i;
 		  /* External port must be unused */
 		  switch (proto)
 		    {
@@ -882,12 +1963,13 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
     if (e_port > 1024)                                                        \
       {                                                                       \
 	a->busy_##n##_ports++;                                                \
-	a->busy_##n##_ports_per_thread[get_thread_idx_by_port (e_port)]++;    \
+	a->busy_##n##_ports_per_thread[nat44_ei_get_thread_idx_by_port (      \
+	  e_port)]++;                                                         \
       }                                                                       \
     break;
 		      foreach_nat_protocol
 #undef _
-			default : nat_elog_info ("unknown protocol");
+			default : nat_elog_info (nm, "unknown protocol");
 		      return VNET_API_ERROR_INVALID_VALUE_2;
 		    }
 		  break;
@@ -898,9 +1980,9 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 	    {
 	      if (sw_if_index != ~0)
 		{
-		  for (i = 0; i < vec_len (sm->to_resolve); i++)
+		  for (i = 0; i < vec_len (nm->to_resolve); i++)
 		    {
-		      rp = sm->to_resolve + i;
+		      rp = nm->to_resolve + i;
 		      if (rp->addr_only)
 			continue;
 		      if (rp->sw_if_index != sw_if_index &&
@@ -909,7 +1991,7 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 			  rp->e_port != e_port && rp->proto != proto)
 			continue;
 
-		      vec_del1 (sm->to_resolve, i);
+		      vec_del1 (nm->to_resolve, i);
 		      break;
 		    }
 		}
@@ -917,14 +1999,14 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 	    }
 	}
 
-      pool_get (sm->static_mappings, m);
+      pool_get (nm->static_mappings, m);
       clib_memset (m, 0, sizeof (*m));
       m->tag = vec_dup (tag);
       m->local_addr = l_addr;
       m->external_addr = e_addr;
 
       if (addr_only)
-	m->flags |= NAT_STATIC_MAPPING_FLAG_ADDR_ONLY;
+	m->flags |= NAT44_EI_STATIC_MAPPING_FLAG_ADDR_ONLY;
       else
 	{
 	  m->local_port = l_port;
@@ -934,7 +2016,7 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
       if (identity_nat)
 	{
-	  m->flags |= NAT_STATIC_MAPPING_FLAG_IDENTITY_NAT;
+	  m->flags |= NAT44_EI_STATIC_MAPPING_FLAG_IDENTITY_NAT;
 	  pool_get (m->locals, local);
 	  local->vrf_id = vrf_id;
 	  local->fib_index = fib_index;
@@ -945,58 +2027,59 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 	  m->fib_index = fib_index;
 	}
 
-      if (sm->num_workers > 1)
+      if (nm->num_workers > 1)
 	{
 	  ip4_header_t ip = {
 	    .src_address = m->local_addr,
 	  };
-	  vec_add1 (m->workers, sm->worker_in2out_cb (&ip, m->fib_index, 0));
-	  tsm = vec_elt_at_index (sm->per_thread_data, m->workers[0]);
+	  vec_add1 (m->workers, nm->worker_in2out_cb (&ip, m->fib_index, 0));
+	  tnm = vec_elt_at_index (nm->per_thread_data, m->workers[0]);
 	}
       else
-	tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
+	tnm = vec_elt_at_index (nm->per_thread_data, nm->num_workers);
 
       init_nat_kv (&kv, m->local_addr, m->local_port, fib_index, m->proto, 0,
-		   m - sm->static_mappings);
-      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
+		   m - nm->static_mappings);
+      clib_bihash_add_del_8_8 (&nm->static_mapping_by_local, &kv, 1);
 
       init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto, 0,
-		   m - sm->static_mappings);
-      clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 1);
+		   m - nm->static_mappings);
+      clib_bihash_add_del_8_8 (&nm->static_mapping_by_external, &kv, 1);
 
       /* Delete dynamic sessions matching local address (+ local port) */
       // TODO: based on type of NAT EI/ED
-      if (!(sm->static_mapping_only))
+      if (!(nm->static_mapping_only))
 	{
 	  u_key.addr = m->local_addr;
 	  u_key.fib_index = m->fib_index;
 	  kv.key = u_key.as_u64;
-	  if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
+	  if (!clib_bihash_search_8_8 (&tnm->user_hash, &kv, &value))
 	    {
 	      user_index = value.value;
-	      u = pool_elt_at_index (tsm->users, user_index);
+	      u = pool_elt_at_index (tnm->users, user_index);
 	      if (u->nsessions)
 		{
 		  head_index = u->sessions_per_user_list_head_index;
-		  head = pool_elt_at_index (tsm->list_pool, head_index);
+		  head = pool_elt_at_index (tnm->list_pool, head_index);
 		  elt_index = head->next;
-		  elt = pool_elt_at_index (tsm->list_pool, elt_index);
+		  elt = pool_elt_at_index (tnm->list_pool, elt_index);
 		  ses_index = elt->value;
 		  while (ses_index != ~0)
 		    {
-		      s = pool_elt_at_index (tsm->sessions, ses_index);
-		      elt = pool_elt_at_index (tsm->list_pool, elt->next);
+		      s = pool_elt_at_index (tnm->sessions, ses_index);
+		      elt = pool_elt_at_index (tnm->list_pool, elt->next);
 		      ses_index = elt->value;
 
-		      if (snat_is_session_static (s))
+		      if (nat44_ei_is_session_static (s))
 			continue;
 
 		      if (!addr_only && s->in2out.port != m->local_port)
 			continue;
 
-		      nat_free_session_data (sm, s, tsm - sm->per_thread_data,
-					     0);
-		      nat44_delete_session (sm, s, tsm - sm->per_thread_data);
+		      nat44_ei_free_session_data_v2 (
+			nm, s, tnm - nm->per_thread_data, 0);
+		      nat44_ei_delete_session (nm, s,
+					       tnm - nm->per_thread_data);
 
 		      if (!addr_only)
 			break;
@@ -1018,7 +2101,7 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       if (identity_nat)
 	{
 	  if (vrf_id == ~0)
-	    vrf_id = sm->inside_vrf_id;
+	    vrf_id = nm->inside_vrf_id;
 
 	  pool_foreach (local, m->locals)
 	    {
@@ -1036,13 +2119,13 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 	fib_index = m->fib_index;
 
       /* Free external address port */
-      if (!(addr_only || sm->static_mapping_only))
+      if (!(addr_only || nm->static_mapping_only))
 	{
-	  for (i = 0; i < vec_len (sm->addresses); i++)
+	  for (i = 0; i < vec_len (nm->addresses); i++)
 	    {
-	      if (sm->addresses[i].addr.as_u32 == e_addr.as_u32)
+	      if (nm->addresses[i].addr.as_u32 == e_addr.as_u32)
 		{
-		  a = sm->addresses + i;
+		  a = nm->addresses + i;
 		  switch (proto)
 		    {
 #define _(N, j, n, s)                                                         \
@@ -1051,7 +2134,8 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
     if (e_port > 1024)                                                        \
       {                                                                       \
 	a->busy_##n##_ports--;                                                \
-	a->busy_##n##_ports_per_thread[get_thread_idx_by_port (e_port)]--;    \
+	a->busy_##n##_ports_per_thread[nat44_ei_get_thread_idx_by_port (      \
+	  e_port)]--;                                                         \
       }                                                                       \
     break;
 		      foreach_nat_protocol
@@ -1063,56 +2147,58 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 	    }
 	}
 
-      if (sm->num_workers > 1)
-	tsm = vec_elt_at_index (sm->per_thread_data, m->workers[0]);
+      if (nm->num_workers > 1)
+	tnm = vec_elt_at_index (nm->per_thread_data, m->workers[0]);
       else
-	tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
+	tnm = vec_elt_at_index (nm->per_thread_data, nm->num_workers);
 
       init_nat_k (&kv, m->local_addr, m->local_port, fib_index, m->proto);
-      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 0);
+      clib_bihash_add_del_8_8 (&nm->static_mapping_by_local, &kv, 0);
 
       /* Delete session(s) for static mapping if exist */
-      if (!(sm->static_mapping_only) ||
-	  (sm->static_mapping_only && sm->static_mapping_connection_tracking))
+      if (!(nm->static_mapping_only) ||
+	  (nm->static_mapping_only && nm->static_mapping_connection_tracking))
 	{
 	  u_key.addr = m->local_addr;
 	  u_key.fib_index = fib_index;
 	  kv.key = u_key.as_u64;
-	  nat44_ei_static_mapping_del_sessions (sm, tsm, u_key, addr_only,
+	  nat44_ei_static_mapping_del_sessions (nm, tnm, u_key, addr_only,
 						e_addr, e_port);
 	}
 
-      fib_table_unlock (fib_index, FIB_PROTOCOL_IP4, sm->fib_src_low);
+      fib_table_unlock (fib_index, FIB_PROTOCOL_IP4, nm->fib_src_low);
       if (pool_elts (m->locals))
 	return 0;
 
       init_nat_k (&kv, m->external_addr, m->external_port, 0, m->proto);
-      clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 0);
+      clib_bihash_add_del_8_8 (&nm->static_mapping_by_external, &kv, 0);
 
       vec_free (m->tag);
       vec_free (m->workers);
       /* Delete static mapping from pool */
-      pool_put (sm->static_mappings, m);
+      pool_put (nm->static_mappings, m);
     }
 
   if (!addr_only || (l_addr.as_u32 == e_addr.as_u32))
     return 0;
 
   /* Add/delete external address to FIB */
-  pool_foreach (interface, sm->interfaces)
+  pool_foreach (interface, nm->interfaces)
     {
-      if (nat_interface_is_inside (interface) || sm->out2in_dpo)
+      if (nat44_ei_interface_is_inside (interface) || nm->out2in_dpo)
 	continue;
 
-      snat_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index, is_add);
+      nat44_ei_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index,
+				    is_add);
       break;
     }
-  pool_foreach (interface, sm->output_feature_interfaces)
+  pool_foreach (interface, nm->output_feature_interfaces)
     {
-      if (nat_interface_is_inside (interface) || sm->out2in_dpo)
+      if (nat44_ei_interface_is_inside (interface) || nm->out2in_dpo)
 	continue;
 
-      snat_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index, is_add);
+      nat44_ei_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index,
+				    is_add);
       break;
     }
   return 0;
@@ -1126,24 +2212,24 @@ nat44_ei_static_mapping_match (ip4_address_t match_addr, u16 match_port,
 			       u32 *mapping_fib_index, u8 by_external,
 			       u8 *is_addr_only, u8 *is_identity_nat)
 {
-  snat_main_t *sm = &snat_main;
+  nat44_ei_main_t *nm = &nat44_ei_main;
   clib_bihash_kv_8_8_t kv, value;
-  snat_static_mapping_t *m;
+  nat44_ei_static_mapping_t *m;
   u16 port;
 
   if (by_external)
     {
       init_nat_k (&kv, match_addr, match_port, 0, match_protocol);
-      if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv,
+      if (clib_bihash_search_8_8 (&nm->static_mapping_by_external, &kv,
 				  &value))
 	{
 	  /* Try address only mapping */
 	  init_nat_k (&kv, match_addr, 0, 0, 0);
-	  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv,
+	  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);
 
       *mapping_fib_index = m->fib_index;
       *mapping_addr = m->local_addr;
@@ -1153,99 +2239,155 @@ nat44_ei_static_mapping_match (ip4_address_t match_addr, u16 match_port,
     {
       init_nat_k (&kv, match_addr, match_port, match_fib_index,
 		  match_protocol);
-      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))
 	{
 	  /* Try address only mapping */
 	  init_nat_k (&kv, match_addr, 0, match_fib_index, 0);
-	  if (clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv,
+	  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);
 
-      *mapping_fib_index = sm->outside_fib_index;
+      *mapping_fib_index = nm->outside_fib_index;
       *mapping_addr = m->external_addr;
       port = m->external_port;
     }
 
   /* Address only mapping doesn't change port */
-  if (is_addr_only_static_mapping (m))
+  if (nat44_ei_is_addr_only_static_mapping (m))
     *mapping_port = match_port;
   else
     *mapping_port = port;
 
   if (PREDICT_FALSE (is_addr_only != 0))
-    *is_addr_only = is_addr_only_static_mapping (m);
+    *is_addr_only = nat44_ei_is_addr_only_static_mapping (m);
 
   if (PREDICT_FALSE (is_identity_nat != 0))
-    *is_identity_nat = is_identity_static_mapping (m);
+    *is_identity_nat = nat44_ei_is_identity_static_mapping (m);
 
   return 0;
 }
 
 static void
-nat44_ei_worker_db_free (snat_main_per_thread_data_t *tsm)
+nat44_ei_worker_db_free (nat44_ei_main_per_thread_data_t *tnm)
+{
+  pool_free (tnm->list_pool);
+  pool_free (tnm->lru_pool);
+  pool_free (tnm->sessions);
+  pool_free (tnm->users);
+
+  clib_bihash_free_8_8 (&tnm->user_hash);
+}
+
+u8 *
+format_nat44_ei_key (u8 *s, va_list *args)
 {
-  pool_free (tsm->list_pool);
-  pool_free (tsm->lru_pool);
-  pool_free (tsm->sessions);
-  pool_free (tsm->users);
+  u64 key = va_arg (*args, u64);
 
-  clib_bihash_free_8_8 (&tsm->user_hash);
+  ip4_address_t addr;
+  u16 port;
+  nat_protocol_t protocol;
+  u32 fib_index;
+
+  split_nat_key (key, &addr, &port, &fib_index, &protocol);
+
+  s = format (s, "%U proto %U port %d fib %d", format_ip4_address, &addr,
+	      format_nat_protocol, protocol, clib_net_to_host_u16 (port),
+	      fib_index);
+  return s;
+}
+
+u8 *
+format_nat44_ei_user_kvp (u8 *s, va_list *args)
+{
+  clib_bihash_kv_8_8_t *v = va_arg (*args, clib_bihash_kv_8_8_t *);
+  nat44_ei_user_key_t k;
+
+  k.as_u64 = v->key;
+
+  s = format (s, "%U fib %d user-index %llu", format_ip4_address, &k.addr,
+	      k.fib_index, v->value);
+
+  return s;
+}
+
+u8 *
+format_nat44_ei_session_kvp (u8 *s, va_list *args)
+{
+  clib_bihash_kv_8_8_t *v = va_arg (*args, clib_bihash_kv_8_8_t *);
+
+  s =
+    format (s, "%U session-index %llu", format_nat44_ei_key, v->key, v->value);
+
+  return s;
+}
+
+u8 *
+format_nat44_ei_static_mapping_kvp (u8 *s, va_list *args)
+{
+  clib_bihash_kv_8_8_t *v = va_arg (*args, clib_bihash_kv_8_8_t *);
+
+  s = format (s, "%U static-mapping-index %llu", format_nat44_ei_key, v->key,
+	      v->value);
+
+  return s;
 }
 
 static void
-nat44_ei_worker_db_init (snat_main_per_thread_data_t *tsm, u32 translations,
-			 u32 translation_buckets, u32 user_buckets)
+nat44_ei_worker_db_init (nat44_ei_main_per_thread_data_t *tnm,
+			 u32 translations, u32 translation_buckets,
+			 u32 user_buckets)
 {
   dlist_elt_t *head;
 
-  pool_alloc (tsm->list_pool, translations);
-  pool_alloc (tsm->lru_pool, translations);
-  pool_alloc (tsm->sessions, translations);
+  pool_alloc (tnm->list_pool, translations);
+  pool_alloc (tnm->lru_pool, translations);
+  pool_alloc (tnm->sessions, translations);
 
-  clib_bihash_init_8_8 (&tsm->user_hash, "users", user_buckets, 0);
+  clib_bihash_init_8_8 (&tnm->user_hash, "users", user_buckets, 0);
 
-  clib_bihash_set_kvp_format_fn_8_8 (&tsm->user_hash, format_user_kvp);
+  clib_bihash_set_kvp_format_fn_8_8 (&tnm->user_hash,
+				     format_nat44_ei_user_kvp);
 
-  pool_get (tsm->lru_pool, head);
-  tsm->tcp_trans_lru_head_index = head - tsm->lru_pool;
-  clib_dlist_init (tsm->lru_pool, tsm->tcp_trans_lru_head_index);
+  pool_get (tnm->lru_pool, head);
+  tnm->tcp_trans_lru_head_index = head - tnm->lru_pool;
+  clib_dlist_init (tnm->lru_pool, tnm->tcp_trans_lru_head_index);
 
-  pool_get (tsm->lru_pool, head);
-  tsm->tcp_estab_lru_head_index = head - tsm->lru_pool;
-  clib_dlist_init (tsm->lru_pool, tsm->tcp_estab_lru_head_index);
+  pool_get (tnm->lru_pool, head);
+  tnm->tcp_estab_lru_head_index = head - tnm->lru_pool;
+  clib_dlist_init (tnm->lru_pool, tnm->tcp_estab_lru_head_index);
 
-  pool_get (tsm->lru_pool, head);
-  tsm->udp_lru_head_index = head - tsm->lru_pool;
-  clib_dlist_init (tsm->lru_pool, tsm->udp_lru_head_index);
+  pool_get (tnm->lru_pool, head);
+  tnm->udp_lru_head_index = head - tnm->lru_pool;
+  clib_dlist_init (tnm->lru_pool, tnm->udp_lru_head_index);
 
-  pool_get (tsm->lru_pool, head);
-  tsm->icmp_lru_head_index = head - tsm->lru_pool;
-  clib_dlist_init (tsm->lru_pool, tsm->icmp_lru_head_index);
+  pool_get (tnm->lru_pool, head);
+  tnm->icmp_lru_head_index = head - tnm->lru_pool;
+  clib_dlist_init (tnm->lru_pool, tnm->icmp_lru_head_index);
 
-  pool_get (tsm->lru_pool, head);
-  tsm->unk_proto_lru_head_index = head - tsm->lru_pool;
-  clib_dlist_init (tsm->lru_pool, tsm->unk_proto_lru_head_index);
+  pool_get (tnm->lru_pool, head);
+  tnm->unk_proto_lru_head_index = head - tnm->lru_pool;
+  clib_dlist_init (tnm->lru_pool, tnm->unk_proto_lru_head_index);
 }
 
 static void
 nat44_ei_db_free ()
 {
-  snat_main_t *sm = &snat_main;
-  snat_main_per_thread_data_t *tsm;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_main_per_thread_data_t *tnm;
 
-  pool_free (sm->static_mappings);
-  clib_bihash_free_8_8 (&sm->static_mapping_by_local);
-  clib_bihash_free_8_8 (&sm->static_mapping_by_external);
+  pool_free (nm->static_mappings);
+  clib_bihash_free_8_8 (&nm->static_mapping_by_local);
+  clib_bihash_free_8_8 (&nm->static_mapping_by_external);
 
-  if (sm->pat)
+  if (nm->pat)
     {
-      clib_bihash_free_8_8 (&sm->in2out);
-      clib_bihash_free_8_8 (&sm->out2in);
-      vec_foreach (tsm, sm->per_thread_data)
+      clib_bihash_free_8_8 (&nm->in2out);
+      clib_bihash_free_8_8 (&nm->out2in);
+      vec_foreach (tnm, nm->per_thread_data)
 	{
-	  nat44_ei_worker_db_free (tsm);
+	  nat44_ei_worker_db_free (tnm);
 	}
     }
 }
@@ -1253,32 +2395,34 @@ nat44_ei_db_free ()
 static void
 nat44_ei_db_init (u32 translations, u32 translation_buckets, u32 user_buckets)
 {
-  snat_main_t *sm = &snat_main;
-  snat_main_per_thread_data_t *tsm;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_main_per_thread_data_t *tnm;
 
   u32 static_mapping_buckets = 1024;
   u32 static_mapping_memory_size = 64 << 20;
 
-  clib_bihash_init_8_8 (&sm->static_mapping_by_local,
+  clib_bihash_init_8_8 (&nm->static_mapping_by_local,
 			"static_mapping_by_local", static_mapping_buckets,
 			static_mapping_memory_size);
-  clib_bihash_init_8_8 (&sm->static_mapping_by_external,
+  clib_bihash_init_8_8 (&nm->static_mapping_by_external,
 			"static_mapping_by_external", static_mapping_buckets,
 			static_mapping_memory_size);
-  clib_bihash_set_kvp_format_fn_8_8 (&sm->static_mapping_by_local,
-				     format_static_mapping_kvp);
-  clib_bihash_set_kvp_format_fn_8_8 (&sm->static_mapping_by_external,
-				     format_static_mapping_kvp);
-
-  if (sm->pat)
-    {
-      clib_bihash_init_8_8 (&sm->in2out, "in2out", translation_buckets, 0);
-      clib_bihash_init_8_8 (&sm->out2in, "out2in", translation_buckets, 0);
-      clib_bihash_set_kvp_format_fn_8_8 (&sm->in2out, format_session_kvp);
-      clib_bihash_set_kvp_format_fn_8_8 (&sm->out2in, format_session_kvp);
-      vec_foreach (tsm, sm->per_thread_data)
+  clib_bihash_set_kvp_format_fn_8_8 (&nm->static_mapping_by_local,
+				     format_nat44_ei_static_mapping_kvp);
+  clib_bihash_set_kvp_format_fn_8_8 (&nm->static_mapping_by_external,
+				     format_nat44_ei_static_mapping_kvp);
+
+  if (nm->pat)
+    {
+      clib_bihash_init_8_8 (&nm->in2out, "in2out", translation_buckets, 0);
+      clib_bihash_init_8_8 (&nm->out2in, "out2in", translation_buckets, 0);
+      clib_bihash_set_kvp_format_fn_8_8 (&nm->in2out,
+					 format_nat44_ei_session_kvp);
+      clib_bihash_set_kvp_format_fn_8_8 (&nm->out2in,
+					 format_nat44_ei_session_kvp);
+      vec_foreach (tnm, nm->per_thread_data)
 	{
-	  nat44_ei_worker_db_init (tsm, translations, translation_buckets,
+	  nat44_ei_worker_db_init (tnm, translations, translation_buckets,
 				   user_buckets);
 	}
     }
@@ -1288,32 +2432,585 @@ void
 nat44_ei_sessions_clear ()
 {
   nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_main_per_thread_data_t *tnm;
 
-  snat_main_per_thread_data_t *tsm;
-  snat_main_t *sm = &snat_main;
-
-  if (sm->pat)
+  if (nm->pat)
     {
-      clib_bihash_free_8_8 (&sm->in2out);
-      clib_bihash_free_8_8 (&sm->out2in);
-      clib_bihash_init_8_8 (&sm->in2out, "in2out", nm->translation_buckets, 0);
-      clib_bihash_init_8_8 (&sm->out2in, "out2in", nm->translation_buckets, 0);
-      clib_bihash_set_kvp_format_fn_8_8 (&sm->in2out, format_session_kvp);
-      clib_bihash_set_kvp_format_fn_8_8 (&sm->out2in, format_session_kvp);
-      vec_foreach (tsm, sm->per_thread_data)
+      clib_bihash_free_8_8 (&nm->in2out);
+      clib_bihash_free_8_8 (&nm->out2in);
+      clib_bihash_init_8_8 (&nm->in2out, "in2out", nm->translation_buckets, 0);
+      clib_bihash_init_8_8 (&nm->out2in, "out2in", nm->translation_buckets, 0);
+      clib_bihash_set_kvp_format_fn_8_8 (&nm->in2out,
+					 format_nat44_ei_session_kvp);
+      clib_bihash_set_kvp_format_fn_8_8 (&nm->out2in,
+					 format_nat44_ei_session_kvp);
+      vec_foreach (tnm, nm->per_thread_data)
 	{
-	  nat44_ei_worker_db_free (tsm);
-	  nat44_ei_worker_db_init (tsm, nm->translations,
+	  nat44_ei_worker_db_free (tnm);
+	  nat44_ei_worker_db_init (tnm, nm->translations,
 				   nm->translation_buckets, nm->user_buckets);
 	}
     }
 
-  // TODO: function for reset counters
-  vlib_zero_simple_counter (&sm->total_users, 0);
-  vlib_zero_simple_counter (&sm->total_sessions, 0);
-  vlib_zero_simple_counter (&sm->user_limit_reached, 0);
+  vlib_zero_simple_counter (&nm->total_users, 0);
+  vlib_zero_simple_counter (&nm->total_sessions, 0);
+  vlib_zero_simple_counter (&nm->user_limit_reached, 0);
 }
 
+static void
+nat44_ei_update_outside_fib (ip4_main_t *im, uword opaque, u32 sw_if_index,
+			     u32 new_fib_index, u32 old_fib_index)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_outside_fib_t *outside_fib;
+  nat44_ei_interface_t *i;
+  u8 is_add = 1;
+  u8 match = 0;
+
+  if (!nm->enabled || (new_fib_index == old_fib_index) ||
+      (!vec_len (nm->outside_fibs)))
+    {
+      return;
+    }
+
+  pool_foreach (i, nm->interfaces)
+    {
+      if (i->sw_if_index == sw_if_index)
+	{
+	  if (!(nat44_ei_interface_is_outside (i)))
+	    return;
+	  match = 1;
+	}
+    }
+
+  pool_foreach (i, nm->output_feature_interfaces)
+    {
+      if (i->sw_if_index == sw_if_index)
+	{
+	  if (!(nat44_ei_interface_is_outside (i)))
+	    return;
+	  match = 1;
+	}
+    }
+
+  if (!match)
+    return;
+
+  vec_foreach (outside_fib, nm->outside_fibs)
+    {
+      if (outside_fib->fib_index == old_fib_index)
+	{
+	  outside_fib->refcount--;
+	  if (!outside_fib->refcount)
+	    vec_del1 (nm->outside_fibs, outside_fib - nm->outside_fibs);
+	  break;
+	}
+    }
+
+  vec_foreach (outside_fib, nm->outside_fibs)
+    {
+      if (outside_fib->fib_index == new_fib_index)
+	{
+	  outside_fib->refcount++;
+	  is_add = 0;
+	  break;
+	}
+    }
+
+  if (is_add)
+    {
+      vec_add2 (nm->outside_fibs, outside_fib, 1);
+      outside_fib->refcount = 1;
+      outside_fib->fib_index = new_fib_index;
+    }
+}
+
+int
+nat44_ei_add_address (nat44_ei_main_t *nm, ip4_address_t *addr, u32 vrf_id)
+{
+  nat44_ei_address_t *ap;
+  nat44_ei_interface_t *i;
+  vlib_thread_main_t *tm = vlib_get_thread_main ();
+
+  /* Check if address already exists */
+  vec_foreach (ap, nm->addresses)
+    {
+      if (ap->addr.as_u32 == addr->as_u32)
+	{
+	  nat44_ei_log_err ("address exist");
+	  return VNET_API_ERROR_VALUE_EXIST;
+	}
+    }
+
+  vec_add2 (nm->addresses, ap, 1);
+
+  ap->addr = *addr;
+  if (vrf_id != ~0)
+    ap->fib_index = fib_table_find_or_create_and_lock (
+      FIB_PROTOCOL_IP4, vrf_id, nm->fib_src_low);
+  else
+    ap->fib_index = ~0;
+
+#define _(N, i, n, s)                                                         \
+  clib_memset (ap->busy_##n##_port_refcounts, 0,                              \
+	       sizeof (ap->busy_##n##_port_refcounts));                       \
+  ap->busy_##n##_ports = 0;                                                   \
+  ap->busy_##n##_ports_per_thread = 0;                                        \
+  vec_validate_init_empty (ap->busy_##n##_ports_per_thread,                   \
+			   tm->n_vlib_mains - 1, 0);
+  foreach_nat_protocol
+#undef _
+
+    /* Add external address to FIB */
+    pool_foreach (i, nm->interfaces)
+  {
+    if (nat44_ei_interface_is_inside (i) || nm->out2in_dpo)
+      continue;
+
+    nat44_ei_add_del_addr_to_fib (addr, 32, i->sw_if_index, 1);
+    break;
+  }
+  pool_foreach (i, nm->output_feature_interfaces)
+    {
+      if (nat44_ei_interface_is_inside (i) || nm->out2in_dpo)
+	continue;
+
+      nat44_ei_add_del_addr_to_fib (addr, 32, i->sw_if_index, 1);
+      break;
+    }
+
+  return 0;
+}
+
+int
+nat44_ei_add_interface_address (nat44_ei_main_t *nm, u32 sw_if_index,
+				int is_del)
+{
+  ip4_main_t *ip4_main = nm->ip4_main;
+  ip4_address_t *first_int_addr;
+  nat44_ei_static_map_resolve_t *rp;
+  u32 *indices_to_delete = 0;
+  int i, j;
+  u32 *auto_add_sw_if_indices = nm->auto_add_sw_if_indices;
+
+  first_int_addr = ip4_interface_first_address (ip4_main, sw_if_index,
+						0 /* just want the address */);
+
+  for (i = 0; i < vec_len (auto_add_sw_if_indices); i++)
+    {
+      if (auto_add_sw_if_indices[i] == sw_if_index)
+	{
+	  if (is_del)
+	    {
+	      /* if have address remove it */
+	      if (first_int_addr)
+		(void) nat44_ei_del_address (nm, first_int_addr[0], 1);
+	      else
+		{
+		  for (j = 0; j < vec_len (nm->to_resolve); j++)
+		    {
+		      rp = nm->to_resolve + j;
+		      if (rp->sw_if_index == sw_if_index)
+			vec_add1 (indices_to_delete, j);
+		    }
+		  if (vec_len (indices_to_delete))
+		    {
+		      for (j = vec_len (indices_to_delete) - 1; j >= 0; j--)
+			vec_del1 (nm->to_resolve, j);
+		      vec_free (indices_to_delete);
+		    }
+		}
+	      vec_del1 (nm->auto_add_sw_if_indices, i);
+	    }
+	  else
+	    return VNET_API_ERROR_VALUE_EXIST;
+
+	  return 0;
+	}
+    }
+
+  if (is_del)
+    return VNET_API_ERROR_NO_SUCH_ENTRY;
+
+  /* add to the auto-address list */
+  vec_add1 (nm->auto_add_sw_if_indices, sw_if_index);
+
+  /* If the address is already bound - or static - add it now */
+  if (first_int_addr)
+    (void) nat44_ei_add_address (nm, first_int_addr, ~0);
+
+  return 0;
+}
+
+static int
+nat44_ei_is_address_used_in_static_mapping (ip4_address_t addr)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_static_mapping_t *m;
+  pool_foreach (m, nm->static_mappings)
+    {
+      if (nat44_ei_is_addr_only_static_mapping (m) ||
+	  nat44_ei_is_identity_static_mapping (m))
+	continue;
+      if (m->external_addr.as_u32 == addr.as_u32)
+	return 1;
+    }
+  return 0;
+}
+
+int
+nat44_ei_del_address (nat44_ei_main_t *nm, ip4_address_t addr, u8 delete_sm)
+{
+  nat44_ei_address_t *a = 0;
+  nat44_ei_session_t *ses;
+  u32 *ses_to_be_removed = 0, *ses_index;
+  nat44_ei_main_per_thread_data_t *tnm;
+  nat44_ei_interface_t *interface;
+  nat44_ei_static_mapping_t *m;
+  int i;
+
+  /* Find SNAT address */
+  for (i = 0; i < vec_len (nm->addresses); i++)
+    {
+      if (nm->addresses[i].addr.as_u32 == addr.as_u32)
+	{
+	  a = nm->addresses + i;
+	  break;
+	}
+    }
+  if (!a)
+    {
+      nat44_ei_log_err ("no such address");
+      return VNET_API_ERROR_NO_SUCH_ENTRY;
+    }
+
+  if (delete_sm)
+    {
+      pool_foreach (m, nm->static_mappings)
+	{
+	  if (m->external_addr.as_u32 == addr.as_u32)
+	    (void) nat44_ei_add_del_static_mapping (
+	      m->local_addr, m->external_addr, m->local_port, m->external_port,
+	      m->proto, ~0 /* sw_if_index */, m->vrf_id,
+	      nat44_ei_is_addr_only_static_mapping (m),
+	      nat44_ei_is_identity_static_mapping (m), m->tag, 0);
+	}
+    }
+  else
+    {
+      /* Check if address is used in some static mapping */
+      if (nat44_ei_is_address_used_in_static_mapping (addr))
+	{
+	  nat44_ei_log_err ("address used in static mapping");
+	  return VNET_API_ERROR_UNSPECIFIED;
+	}
+    }
+
+  if (a->fib_index != ~0)
+    fib_table_unlock (a->fib_index, FIB_PROTOCOL_IP4, nm->fib_src_low);
+
+  /* Delete sessions using address */
+  if (a->busy_tcp_ports || a->busy_udp_ports || a->busy_icmp_ports)
+    {
+      vec_foreach (tnm, nm->per_thread_data)
+	{
+	  pool_foreach (ses, tnm->sessions)
+	    {
+	      if (ses->out2in.addr.as_u32 == addr.as_u32)
+		{
+		  nat44_ei_free_session_data (nm, ses,
+					      tnm - nm->per_thread_data, 0);
+		  vec_add1 (ses_to_be_removed, ses - tnm->sessions);
+		}
+	    }
+	  vec_foreach (ses_index, ses_to_be_removed)
+	    {
+	      ses = pool_elt_at_index (tnm->sessions, ses_index[0]);
+	      nat44_ei_delete_session (nm, ses, tnm - nm->per_thread_data);
+	    }
+	  vec_free (ses_to_be_removed);
+	}
+    }
+
+#define _(N, i, n, s) vec_free (a->busy_##n##_ports_per_thread);
+  foreach_nat_protocol
+#undef _
+    vec_del1 (nm->addresses, i);
+
+  /* Delete external address from FIB */
+  pool_foreach (interface, nm->interfaces)
+    {
+      if (nat44_ei_interface_is_inside (interface) || nm->out2in_dpo)
+	continue;
+      nat44_ei_add_del_addr_to_fib (&addr, 32, interface->sw_if_index, 0);
+      break;
+    }
+
+  pool_foreach (interface, nm->output_feature_interfaces)
+    {
+      if (nat44_ei_interface_is_inside (interface) || nm->out2in_dpo)
+	continue;
+      nat44_ei_add_del_addr_to_fib (&addr, 32, interface->sw_if_index, 0);
+      break;
+    }
+
+  return 0;
+}
+
+static void
+nat44_ei_ip4_add_del_interface_address_cb (ip4_main_t *im, uword opaque,
+					   u32 sw_if_index,
+					   ip4_address_t *address,
+					   u32 address_length,
+					   u32 if_address_index, u32 is_delete)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_static_map_resolve_t *rp;
+  ip4_address_t l_addr;
+  int i, j;
+  int rv;
+  nat44_ei_address_t *addresses = nm->addresses;
+
+  if (!nm->enabled)
+    return;
+
+  for (i = 0; i < vec_len (nm->auto_add_sw_if_indices); i++)
+    {
+      if (sw_if_index == nm->auto_add_sw_if_indices[i])
+	goto match;
+    }
+
+  return;
+
+match:
+  if (!is_delete)
+    {
+      /* Don't trip over lease renewal, static config */
+      for (j = 0; j < vec_len (addresses); j++)
+	if (addresses[j].addr.as_u32 == address->as_u32)
+	  return;
+
+      (void) nat44_ei_add_address (nm, address, ~0);
+      /* Scan static map resolution vector */
+      for (j = 0; j < vec_len (nm->to_resolve); j++)
+	{
+	  rp = nm->to_resolve + j;
+	  if (rp->addr_only)
+	    continue;
+	  /* On this interface? */
+	  if (rp->sw_if_index == sw_if_index)
+	    {
+	      /* Indetity mapping? */
+	      if (rp->l_addr.as_u32 == 0)
+		l_addr.as_u32 = address[0].as_u32;
+	      else
+		l_addr.as_u32 = rp->l_addr.as_u32;
+	      /* Add the static mapping */
+	      rv = nat44_ei_add_del_static_mapping (
+		l_addr, address[0], rp->l_port, rp->e_port, rp->proto,
+		~0 /* sw_if_index */, rp->vrf_id, rp->addr_only,
+		rp->identity_nat, rp->tag, 1);
+	      if (rv)
+		nat_elog_notice_X1 (
+		  nm, "nat44_ei_add_del_static_mapping returned %d", "i4", rv);
+	    }
+	}
+      return;
+    }
+  else
+    {
+      (void) nat44_ei_del_address (nm, address[0], 1);
+      return;
+    }
+}
+
+int
+nat44_ei_set_frame_queue_nelts (u32 frame_queue_nelts)
+{
+  fail_if_enabled ();
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nm->frame_queue_nelts = frame_queue_nelts;
+  return 0;
+}
+
+static void
+nat44_ei_ip4_add_del_addr_only_sm_cb (ip4_main_t *im, uword opaque,
+				      u32 sw_if_index, ip4_address_t *address,
+				      u32 address_length, u32 if_address_index,
+				      u32 is_delete)
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_static_map_resolve_t *rp;
+  nat44_ei_static_mapping_t *m;
+  clib_bihash_kv_8_8_t kv, value;
+  int i, rv;
+  ip4_address_t l_addr;
+
+  if (!nm->enabled)
+    return;
+
+  for (i = 0; i < vec_len (nm->to_resolve); i++)
+    {
+      rp = nm->to_resolve + i;
+      if (rp->addr_only == 0)
+	continue;
+      if (rp->sw_if_index == sw_if_index)
+	goto match;
+    }
+
+  return;
+
+match:
+  init_nat_k (&kv, *address, rp->addr_only ? 0 : rp->e_port,
+	      nm->outside_fib_index, rp->addr_only ? 0 : rp->proto);
+  if (clib_bihash_search_8_8 (&nm->static_mapping_by_external, &kv, &value))
+    m = 0;
+  else
+    m = pool_elt_at_index (nm->static_mappings, value.value);
+
+  if (!is_delete)
+    {
+      /* Don't trip over lease renewal, static config */
+      if (m)
+	return;
+    }
+  else
+    {
+      if (!m)
+	return;
+    }
+
+  /* Indetity mapping? */
+  if (rp->l_addr.as_u32 == 0)
+    l_addr.as_u32 = address[0].as_u32;
+  else
+    l_addr.as_u32 = rp->l_addr.as_u32;
+  /* Add the static mapping */
+
+  rv = nat44_ei_add_del_static_mapping (
+    l_addr, address[0], rp->l_port, rp->e_port, rp->proto,
+    ~0 /* sw_if_index */, rp->vrf_id, rp->addr_only, rp->identity_nat, rp->tag,
+    !is_delete);
+  if (rv)
+    nat_elog_notice_X1 (nm, "nat44_ei_add_del_static_mapping returned %d",
+			"i4", rv);
+}
+
+VLIB_NODE_FN (nat44_ei_classify_node)
+(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+  u32 n_left_from, *from, *to_next;
+  nat44_ei_classify_next_t next_index;
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  nat44_ei_static_mapping_t *m;
+  u32 next_in2out = 0, next_out2in = 0;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0 = NAT44_EI_CLASSIFY_NEXT_IN2OUT;
+	  ip4_header_t *ip0;
+	  nat44_ei_address_t *ap;
+	  clib_bihash_kv_8_8_t kv0, value0;
+
+	  /* speculatively enqueue b0 to the current next frame */
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  ip0 = vlib_buffer_get_current (b0);
+
+	  vec_foreach (ap, nm->addresses)
+	    {
+	      if (ip0->dst_address.as_u32 == ap->addr.as_u32)
+		{
+		  next0 = NAT44_EI_CLASSIFY_NEXT_OUT2IN;
+		  goto enqueue0;
+		}
+	    }
+
+	  if (PREDICT_FALSE (pool_elts (nm->static_mappings)))
+	    {
+	      init_nat_k (&kv0, ip0->dst_address, 0, 0, 0);
+	      /* try to classify the fragment based on IP header alone */
+	      if (!clib_bihash_search_8_8 (&nm->static_mapping_by_external,
+					   &kv0, &value0))
+		{
+		  m = pool_elt_at_index (nm->static_mappings, value0.value);
+		  if (m->local_addr.as_u32 != m->external_addr.as_u32)
+		    next0 = NAT44_EI_CLASSIFY_NEXT_OUT2IN;
+		  goto enqueue0;
+		}
+	      init_nat_k (&kv0, ip0->dst_address,
+			  vnet_buffer (b0)->ip.reass.l4_dst_port, 0,
+			  ip_proto_to_nat_proto (ip0->protocol));
+	      if (!clib_bihash_search_8_8 (&nm->static_mapping_by_external,
+					   &kv0, &value0))
+		{
+		  m = pool_elt_at_index (nm->static_mappings, value0.value);
+		  if (m->local_addr.as_u32 != m->external_addr.as_u32)
+		    next0 = NAT44_EI_CLASSIFY_NEXT_OUT2IN;
+		}
+	    }
+
+	enqueue0:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
+			     (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      nat44_ei_classify_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->cached = 0;
+	      t->next_in2out = next0 == NAT44_EI_CLASSIFY_NEXT_IN2OUT ? 1 : 0;
+	    }
+
+	  next_in2out += next0 == NAT44_EI_CLASSIFY_NEXT_IN2OUT;
+	  next_out2in += next0 == NAT44_EI_CLASSIFY_NEXT_OUT2IN;
+
+	  /* verify speculative enqueue, maybe switch current next frame */
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+					   n_left_to_next, bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  vlib_node_increment_counter (
+    vm, node->node_index, NAT44_EI_CLASSIFY_ERROR_NEXT_IN2OUT, next_in2out);
+  vlib_node_increment_counter (
+    vm, node->node_index, NAT44_EI_CLASSIFY_ERROR_NEXT_OUT2IN, next_out2in);
+  return frame->n_vectors;
+}
+
+VLIB_REGISTER_NODE (nat44_ei_classify_node) = {
+  .name = "nat44-ei-classify",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat44_ei_classify_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN(nat44_ei_classify_error_strings),
+  .error_strings = nat44_ei_classify_error_strings,
+  .n_next_nodes = NAT44_EI_CLASSIFY_N_NEXT,
+  .next_nodes = {
+    [NAT44_EI_CLASSIFY_NEXT_IN2OUT] = "nat44-ei-in2out",
+    [NAT44_EI_CLASSIFY_NEXT_OUT2IN] = "nat44-ei-out2in",
+    [NAT44_EI_CLASSIFY_NEXT_DROP] = "error-drop",
+  },
+};
+
 /*
  * fd.io coding-style-patch-verification: ON
  *