nat: api,cli and test update & cleanup
[vpp.git] / src / plugins / nat / nat.c
old mode 100755 (executable)
new mode 100644 (file)
index 0cfcbf1..39dd1db
 #include <vnet/plugin/plugin.h>
 #include <nat/nat.h>
 #include <nat/nat_dpo.h>
-#include <nat/nat_ipfix_logging.h>
-#include <nat/nat_det.h>
-#include <nat/nat64.h>
-#include <nat/nat66.h>
-#include <nat/dslite.h>
-#include <nat/nat_reass.h>
+#include <nat/lib/ipfix_logging.h>
 #include <nat/nat_inlines.h>
+#include <nat/nat44/inlines.h>
 #include <nat/nat_affinity.h>
 #include <nat/nat_syslog.h>
+#include <nat/nat_ha.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 <vpp/app/version.h>
 
 snat_main_t snat_main;
 
 /* *INDENT-OFF* */
-
 /* Hook up input features */
-VNET_FEATURE_INIT (ip4_snat_in2out, static) = {
+VNET_FEATURE_INIT (nat_pre_in2out, static) = {
   .arc_name = "ip4-unicast",
-  .node_name = "nat44-in2out",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
+  .node_name = "nat-pre-in2out",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+                              "ip4-sv-reassembly-feature"),
 };
-VNET_FEATURE_INIT (ip4_snat_out2in, static) = {
+VNET_FEATURE_INIT (nat_pre_out2in, static) = {
   .arc_name = "ip4-unicast",
-  .node_name = "nat44-out2in",
+  .node_name = "nat-pre-out2in",
   .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
-                               "ip4-dhcp-client-detect"),
+                               "ip4-dhcp-client-detect",
+                              "ip4-sv-reassembly-feature"),
 };
-VNET_FEATURE_INIT (ip4_nat_classify, static) = {
+VNET_FEATURE_INIT (snat_in2out_worker_handoff, static) = {
   .arc_name = "ip4-unicast",
-  .node_name = "nat44-classify",
+  .node_name = "nat44-in2out-worker-handoff",
   .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
 };
-VNET_FEATURE_INIT (ip4_snat_det_in2out, static) = {
+VNET_FEATURE_INIT (snat_out2in_worker_handoff, static) = {
   .arc_name = "ip4-unicast",
-  .node_name = "nat44-det-in2out",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
+  .node_name = "nat44-out2in-worker-handoff",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+                               "ip4-dhcp-client-detect"),
+};
+VNET_FEATURE_INIT (ip4_snat_in2out, static) = {
+  .arc_name = "ip4-unicast",
+  .node_name = "nat44-in2out",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature"),
 };
-VNET_FEATURE_INIT (ip4_snat_det_out2in, static) = {
+VNET_FEATURE_INIT (ip4_snat_out2in, static) = {
   .arc_name = "ip4-unicast",
-  .node_name = "nat44-det-out2in",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+  .node_name = "nat44-out2in",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature",
                                "ip4-dhcp-client-detect"),
 };
-VNET_FEATURE_INIT (ip4_nat_det_classify, static) = {
+VNET_FEATURE_INIT (ip4_nat_classify, static) = {
   .arc_name = "ip4-unicast",
-  .node_name = "nat44-det-classify",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
+  .node_name = "nat44-classify",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature"),
 };
 VNET_FEATURE_INIT (ip4_nat44_ed_in2out, static) = {
   .arc_name = "ip4-unicast",
   .node_name = "nat44-ed-in2out",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature"),
 };
 VNET_FEATURE_INIT (ip4_nat44_ed_out2in, static) = {
   .arc_name = "ip4-unicast",
   .node_name = "nat44-ed-out2in",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature",
                                "ip4-dhcp-client-detect"),
 };
 VNET_FEATURE_INIT (ip4_nat44_ed_classify, static) = {
   .arc_name = "ip4-unicast",
   .node_name = "nat44-ed-classify",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
-};
-VNET_FEATURE_INIT (ip4_snat_in2out_worker_handoff, static) = {
-  .arc_name = "ip4-unicast",
-  .node_name = "nat44-in2out-worker-handoff",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
-};
-VNET_FEATURE_INIT (ip4_snat_out2in_worker_handoff, static) = {
-  .arc_name = "ip4-unicast",
-  .node_name = "nat44-out2in-worker-handoff",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
-                               "ip4-dhcp-client-detect"),
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature"),
 };
 VNET_FEATURE_INIT (ip4_nat_handoff_classify, static) = {
   .arc_name = "ip4-unicast",
   .node_name = "nat44-handoff-classify",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature"),
 };
 VNET_FEATURE_INIT (ip4_snat_in2out_fast, static) = {
   .arc_name = "ip4-unicast",
   .node_name = "nat44-in2out-fast",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature"),
 };
 VNET_FEATURE_INIT (ip4_snat_out2in_fast, static) = {
   .arc_name = "ip4-unicast",
   .node_name = "nat44-out2in-fast",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa",
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature",
                                "ip4-dhcp-client-detect"),
 };
 VNET_FEATURE_INIT (ip4_snat_hairpin_dst, static) = {
   .arc_name = "ip4-unicast",
   .node_name = "nat44-hairpin-dst",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature"),
 };
 VNET_FEATURE_INIT (ip4_nat44_ed_hairpin_dst, static) = {
   .arc_name = "ip4-unicast",
   .node_name = "nat44-ed-hairpin-dst",
-  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa"),
+  .runs_after = VNET_FEATURES ("acl-plugin-in-ip4-fa","ip4-sv-reassembly-feature"),
 };
 
 /* Hook up output features */
 VNET_FEATURE_INIT (ip4_snat_in2out_output, static) = {
   .arc_name = "ip4-output",
   .node_name = "nat44-in2out-output",
-  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa"),
+  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa","ip4-sv-reassembly-output-feature"),
 };
 VNET_FEATURE_INIT (ip4_snat_in2out_output_worker_handoff, static) = {
   .arc_name = "ip4-output",
   .node_name = "nat44-in2out-output-worker-handoff",
-  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa"),
+  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa","ip4-sv-reassembly-output-feature"),
 };
 VNET_FEATURE_INIT (ip4_snat_hairpin_src, static) = {
   .arc_name = "ip4-output",
   .node_name = "nat44-hairpin-src",
-  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa"),
+  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa","ip4-sv-reassembly-output-feature"),
+};
+VNET_FEATURE_INIT (nat_pre_in2out_output, static) = {
+  .arc_name = "ip4-output",
+  .node_name = "nat-pre-in2out-output",
+  .runs_after = VNET_FEATURES ("ip4-sv-reassembly-output-feature"),
+  .runs_before = VNET_FEATURES ("acl-plugin-out-ip4-fa"),
 };
 VNET_FEATURE_INIT (ip4_nat44_ed_in2out_output, static) = {
   .arc_name = "ip4-output",
   .node_name = "nat44-ed-in2out-output",
-  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa"),
+  .runs_after = VNET_FEATURES ("ip4-sv-reassembly-output-feature"),
+  .runs_before = VNET_FEATURES ("acl-plugin-out-ip4-fa"),
 };
 VNET_FEATURE_INIT (ip4_nat44_ed_hairpin_src, static) = {
   .arc_name = "ip4-output",
   .node_name = "nat44-ed-hairpin-src",
-  .runs_after = VNET_FEATURES ("acl-plugin-out-ip4-fa"),
+  .runs_after = VNET_FEATURES ("ip4-sv-reassembly-output-feature"),
+  .runs_before = VNET_FEATURES ("acl-plugin-out-ip4-fa"),
 };
 
 /* Hook up ip4-local features */
@@ -170,32 +175,241 @@ VNET_FEATURE_INIT (ip4_nat44_ed_hairpinning, static) =
 
 VLIB_PLUGIN_REGISTER () = {
     .version = VPP_BUILD_VER,
-    .description = "Network Address Translation",
+    .description = "Network Address Translation (NAT)",
 };
 /* *INDENT-ON* */
 
+static u32
+nat44_ed_get_worker_out2in_cb (vlib_buffer_t * b, ip4_header_t * ip,
+                              u32 rx_fib_index, u8 is_output);
+
+static u32
+nat44_ed_get_worker_in2out_cb (ip4_header_t * ip, u32 rx_fib_index,
+                              u8 is_output);
+
+static u32
+snat_get_worker_out2in_cb (vlib_buffer_t * b, ip4_header_t * ip0,
+                          u32 rx_fib_index0, u8 is_output);
+
+static u32
+snat_get_worker_in2out_cb (ip4_header_t * ip0, u32 rx_fib_index0,
+                          u8 is_output);
+
+static u32 nat_calc_bihash_buckets (u32 n_elts);
+
+u8 *
+format_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_snat_key, v->key, v->value);
+
+  return s;
+}
+
+u8 *
+format_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_snat_key, v->key, v->value);
+
+  return s;
+}
+
+u8 *
+format_user_kvp (u8 * s, va_list * args)
+{
+  clib_bihash_kv_8_8_t *v = va_arg (*args, clib_bihash_kv_8_8_t *);
+  snat_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_ed_session_kvp (u8 * s, va_list * args)
+{
+  clib_bihash_kv_16_8_t *v = va_arg (*args, clib_bihash_kv_16_8_t *);
+
+  u8 proto;
+  u16 r_port, l_port;
+  ip4_address_t l_addr, r_addr;
+  u32 fib_index;
+
+  split_ed_kv (v, &l_addr, &r_addr, &proto, &fib_index, &l_port, &r_port);
+  s =
+    format (s,
+           "local %U:%d remote %U:%d proto %U fib %d thread-index %u session-index %u",
+           format_ip4_address, &l_addr, clib_net_to_host_u16 (l_port),
+           format_ip4_address, &r_addr, clib_net_to_host_u16 (r_port),
+           format_ip_protocol, proto, fib_index,
+           ed_value_get_session_index (v), ed_value_get_thread_index (v));
+
+  return s;
+}
+
+void
+nat44_ei_free_session_data (snat_main_t * sm, snat_session_t * s,
+                           u32 thread_index, u8 is_ha)
+{
+  clib_bihash_kv_8_8_t kv;
+
+  snat_main_per_thread_data_t *tsm =
+    vec_elt_at_index (sm->per_thread_data, thread_index);
+
+  init_nat_i2o_k (&kv, s);
+  if (clib_bihash_add_del_8_8 (&tsm->in2out, &kv, 0))
+    nat_elog_warn ("in2out key del failed");
+
+  init_nat_o2i_k (&kv, s);
+  if (clib_bihash_add_del_8_8 (&tsm->out2in, &kv, 0))
+    nat_elog_warn ("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);
+
+      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 (snat_is_session_static (s))
+    return;
+
+  snat_free_outside_address_and_port (sm->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)
+{
+  dlist_elt_t *elt;
+  snat_session_t *s;
+
+  snat_main_t *sm = &snat_main;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+
+  // get head
+  elt = pool_elt_at_index (tsm->list_pool,
+                          u->sessions_per_user_list_head_index);
+  // get first element
+  elt = pool_elt_at_index (tsm->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);
+
+      nat44_ei_free_session_data (sm, s, thread_index, 0);
+      nat44_delete_session (sm, s, thread_index);
+    }
+}
+
+int
+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;
+
+  snat_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)
+    {
+      /* *INDENT-OFF* */
+      vec_foreach (tsm, sm->per_thread_data)
+        {
+          if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
+            {
+              nat44_ei_user_del_sessions (
+                  pool_elt_at_index (tsm->users, value.value),
+                  tsm->thread_index);
+              rv = 0;
+              break;
+            }
+        }
+      /* *INDENT-ON* */
+    }
+  else
+    {
+      tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
+      if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
+       {
+         nat44_ei_user_del_sessions (pool_elt_at_index
+                                     (tsm->users, value.value),
+                                     tsm->thread_index);
+         rv = 0;
+       }
+    }
+  return rv;
+}
+
 void
-nat_free_session_data (snat_main_t * sm, snat_session_t * s, u32 thread_index)
+nat_free_session_data (snat_main_t * sm, snat_session_t * s, u32 thread_index,
+                      u8 is_ha)
 {
-  snat_session_key_t key;
   clib_bihash_kv_8_8_t kv;
-  nat_ed_ses_key_t ed_key;
+  u8 proto;
+  u16 r_port, l_port;
+  ip4_address_t *l_addr, *r_addr;
+  u32 fib_index = 0;
   clib_bihash_kv_16_8_t ed_kv;
   snat_main_per_thread_data_t *tsm =
     vec_elt_at_index (sm->per_thread_data, thread_index);
 
+  if (is_ed_session (s))
+    {
+      per_vrf_sessions_unregister_session (s, thread_index);
+    }
+
   if (is_fwd_bypass_session (s))
     {
-      ed_key.l_addr = s->in2out.addr;
-      ed_key.r_addr = s->ext_host_addr;
-      ed_key.l_port = s->in2out.port;
-      ed_key.r_port = s->ext_host_port;
-      ed_key.proto = snat_proto_to_ip_proto (s->in2out.protocol);
-      ed_key.fib_index = 0;
-      ed_kv.key[0] = ed_key.as_u64[0];
-      ed_kv.key[1] = ed_key.as_u64[1];
+      if (snat_is_unk_proto_session (s))
+       {
+         init_ed_k (&ed_kv, s->in2out.addr, 0, s->ext_host_addr, 0, 0,
+                    s->in2out.port);
+       }
+      else
+       {
+         l_port = s->in2out.port;
+         r_port = s->ext_host_port;
+         l_addr = &s->in2out.addr;
+         r_addr = &s->ext_host_addr;
+         proto = nat_proto_to_ip_proto (s->nat_proto);
+         fib_index = s->in2out.fib_index;
+         init_ed_k (&ed_kv, *l_addr, l_port, *r_addr, r_port, fib_index,
+                    proto);
+       }
       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &ed_kv, 0))
-       nat_log_warn ("in2out_ed key del failed");
+       nat_elog_warn ("in2out_ed key del failed");
       return;
     }
 
@@ -204,87 +418,96 @@ nat_free_session_data (snat_main_t * sm, snat_session_t * s, u32 thread_index)
     {
       if (is_affinity_sessions (s))
        nat_affinity_unlock (s->ext_host_addr, s->out2in.addr,
-                            s->in2out.protocol, s->out2in.port);
-      ed_key.l_addr = s->out2in.addr;
-      ed_key.r_addr = s->ext_host_addr;
-      ed_key.fib_index = s->out2in.fib_index;
+                            s->nat_proto, s->out2in.port);
+      l_addr = &s->out2in.addr;
+      r_addr = &s->ext_host_addr;
+      fib_index = s->out2in.fib_index;
       if (snat_is_unk_proto_session (s))
        {
-         ed_key.proto = s->in2out.port;
-         ed_key.r_port = 0;
-         ed_key.l_port = 0;
+         proto = s->in2out.port;
+         r_port = 0;
+         l_port = 0;
        }
       else
        {
-         ed_key.proto = snat_proto_to_ip_proto (s->in2out.protocol);
-         ed_key.l_port = s->out2in.port;
-         ed_key.r_port = s->ext_host_port;
+         proto = nat_proto_to_ip_proto (s->nat_proto);
+         l_port = s->out2in.port;
+         r_port = s->ext_host_port;
        }
-      ed_kv.key[0] = ed_key.as_u64[0];
-      ed_kv.key[1] = ed_key.as_u64[1];
-      if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &ed_kv, 0))
-       nat_log_warn ("out2in_ed key del failed");
-      ed_key.l_addr = s->in2out.addr;
-      ed_key.fib_index = s->in2out.fib_index;
+      init_ed_k (&ed_kv, *l_addr, l_port, *r_addr, r_port, fib_index, proto);
+      if (clib_bihash_add_del_16_8 (&sm->out2in_ed, &ed_kv, 0))
+       nat_elog_warn ("out2in_ed key del failed");
+      l_addr = &s->in2out.addr;
+      fib_index = s->in2out.fib_index;
       if (!snat_is_unk_proto_session (s))
-       ed_key.l_port = s->in2out.port;
+       l_port = s->in2out.port;
       if (is_twice_nat_session (s))
        {
-         ed_key.r_addr = s->ext_host_nat_addr;
-         ed_key.r_port = s->ext_host_nat_port;
+         r_addr = &s->ext_host_nat_addr;
+         r_port = s->ext_host_nat_port;
        }
-      ed_kv.key[0] = ed_key.as_u64[0];
-      ed_kv.key[1] = ed_key.as_u64[1];
+      init_ed_k (&ed_kv, *l_addr, l_port, *r_addr, r_port, fib_index, proto);
       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &ed_kv, 0))
-       nat_log_warn ("in2out_ed key del failed");
+       nat_elog_warn ("in2out_ed key del failed");
 
-      nat_syslog_nat44_sdel (s->user_index, s->in2out.fib_index,
-                            &s->in2out.addr, s->in2out.port,
-                            &s->ext_host_nat_addr, s->ext_host_nat_port,
-                            &s->out2in.addr, s->out2in.port,
-                            &s->ext_host_addr, s->ext_host_port,
-                            s->in2out.protocol, is_twice_nat_session (s));
+      if (!is_ha)
+       nat_syslog_nat44_sdel (s->user_index, s->in2out.fib_index,
+                              &s->in2out.addr, s->in2out.port,
+                              &s->ext_host_nat_addr, s->ext_host_nat_port,
+                              &s->out2in.addr, s->out2in.port,
+                              &s->ext_host_addr, s->ext_host_port,
+                              s->nat_proto, is_twice_nat_session (s));
     }
   else
     {
-      kv.key = s->in2out.as_u64;
+      init_nat_i2o_k (&kv, s);
       if (clib_bihash_add_del_8_8 (&tsm->in2out, &kv, 0))
-       nat_log_warn ("in2out key del failed");
-      kv.key = s->out2in.as_u64;
+       nat_elog_warn ("in2out key del failed");
+      init_nat_o2i_k (&kv, s);
       if (clib_bihash_add_del_8_8 (&tsm->out2in, &kv, 0))
-       nat_log_warn ("out2in key del failed");
+       nat_elog_warn ("out2in key del failed");
 
-      nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
-                              &s->in2out.addr, s->in2out.port,
-                              &s->out2in.addr, s->out2in.port,
-                              s->in2out.protocol);
+      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 (snat_is_unk_proto_session (s))
     return;
 
-  /* log NAT event */
-  snat_ipfix_logging_nat44_ses_delete (s->in2out.addr.as_u32,
-                                      s->out2in.addr.as_u32,
-                                      s->in2out.protocol,
-                                      s->in2out.port,
-                                      s->out2in.port, s->in2out.fib_index);
+  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);
+    }
 
   /* Twice NAT address and port for external host */
   if (is_twice_nat_session (s))
     {
-      key.protocol = s->in2out.protocol;
-      key.port = s->ext_host_nat_port;
-      key.addr.as_u32 = s->ext_host_nat_addr.as_u32;
       snat_free_outside_address_and_port (sm->twice_nat_addresses,
-                                         thread_index, &key);
+                                         thread_index,
+                                         &s->ext_host_nat_addr,
+                                         s->ext_host_nat_port, s->nat_proto);
     }
 
   if (snat_is_session_static (s))
     return;
 
   snat_free_outside_address_and_port (sm->addresses, thread_index,
-                                     &s->out2in);
+                                     &s->out2in.addr, s->out2in.port,
+                                     s->nat_proto);
 }
 
 snat_user_t *
@@ -304,9 +527,17 @@ nat_user_get_or_create (snat_main_t * sm, ip4_address_t * addr, u32 fib_index,
   /* Ever heard of the "user" = src ip4 address before? */
   if (clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
     {
+      if (pool_elts (tsm->users) >= sm->max_users_per_thread)
+       {
+         vlib_increment_simple_counter (&sm->user_limit_reached,
+                                        thread_index, 0, 1);
+         nat_elog_warn ("maximum user limit reached");
+         return NULL;
+       }
       /* no, make a new one */
       pool_get (tsm->users, u);
       clib_memset (u, 0, sizeof (*u));
+
       u->addr.as_u32 = addr->as_u32;
       u->fib_index = fib_index;
 
@@ -321,7 +552,11 @@ nat_user_get_or_create (snat_main_t * sm, ip4_address_t * addr, u32 fib_index,
 
       /* add user */
       if (clib_bihash_add_del_8_8 (&tsm->user_hash, &kv, 1))
-       nat_log_warn ("user_hash keay add failed");
+       {
+         nat_elog_warn ("user_hash key add failed");
+         nat44_delete_user_with_no_session (sm, u, thread_index);
+         return NULL;
+       }
 
       vlib_set_simple_counter (&sm->total_users, thread_index, 0,
                               pool_elts (tsm->users));
@@ -334,9 +569,10 @@ nat_user_get_or_create (snat_main_t * sm, ip4_address_t * addr, u32 fib_index,
   return u;
 }
 
+// only NAT EI
 snat_session_t *
 nat_session_alloc_or_recycle (snat_main_t * sm, snat_user_t * u,
-                             u32 thread_index)
+                             u32 thread_index, f64 now)
 {
   snat_session_t *s;
   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
@@ -367,7 +603,9 @@ nat_session_alloc_or_recycle (snat_main_t * sm, snat_user_t * u,
 
       /* Get the session */
       s = pool_elt_at_index (tsm->sessions, session_index);
-      nat_free_session_data (sm, s, thread_index);
+
+      // TODO: ONLY EI version should be called
+      nat_free_session_data (sm, s, thread_index, 0);
       if (snat_is_session_static (s))
        u->nstaticsessions--;
       else
@@ -404,82 +642,7 @@ nat_session_alloc_or_recycle (snat_main_t * sm, snat_user_t * u,
                               pool_elts (tsm->sessions));
     }
 
-  return s;
-}
-
-snat_session_t *
-nat_ed_session_alloc (snat_main_t * sm, snat_user_t * u, u32 thread_index,
-                     f64 now)
-{
-  snat_session_t *s;
-  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
-  dlist_elt_t *per_user_translation_list_elt, *oldest_elt;
-  u32 oldest_index;
-  u64 sess_timeout_time;
-
-  if (PREDICT_FALSE (!(u->nsessions) && !(u->nstaticsessions)))
-    goto alloc_new;
-
-  oldest_index =
-    clib_dlist_remove_head (tsm->list_pool,
-                           u->sessions_per_user_list_head_index);
-  oldest_elt = pool_elt_at_index (tsm->list_pool, oldest_index);
-  s = pool_elt_at_index (tsm->sessions, oldest_elt->value);
-  sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
-  if (now >= sess_timeout_time)
-    {
-      clib_dlist_addtail (tsm->list_pool,
-                         u->sessions_per_user_list_head_index, oldest_index);
-      nat_free_session_data (sm, s, thread_index);
-      if (snat_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
-    {
-      clib_dlist_addhead (tsm->list_pool,
-                         u->sessions_per_user_list_head_index, oldest_index);
-      if ((u->nsessions + u->nstaticsessions) >=
-         sm->max_translations_per_user)
-       {
-         nat_log_warn ("max translations per user %U", format_ip4_address,
-                       &u->addr);
-         snat_ipfix_logging_max_entries_per_user
-           (sm->max_translations_per_user, u->addr.as_u32);
-         return 0;
-       }
-      else
-       {
-       alloc_new:
-         pool_get (tsm->sessions, s);
-         clib_memset (s, 0, sizeof (*s));
-
-         /* Create list elts */
-         pool_get (tsm->list_pool, per_user_translation_list_elt);
-         clib_dlist_init (tsm->list_pool,
-                          per_user_translation_list_elt - tsm->list_pool);
-
-         per_user_translation_list_elt->value = s - tsm->sessions;
-         s->per_user_index = per_user_translation_list_elt - tsm->list_pool;
-         s->per_user_list_head_index = u->sessions_per_user_list_head_index;
-
-         clib_dlist_addtail (tsm->list_pool,
-                             s->per_user_list_head_index,
-                             per_user_translation_list_elt - tsm->list_pool);
-       }
-
-      vlib_set_simple_counter (&sm->total_sessions, thread_index, 0,
-                              pool_elts (tsm->sessions));
-    }
+  s->ha_last_refreshed = now;
 
   return s;
 }
@@ -488,6 +651,7 @@ void
 snat_add_del_addr_to_fib (ip4_address_t * addr, u8 p_len, u32 sw_if_index,
                          int is_add)
 {
+  snat_main_t *sm = &snat_main;
   fib_prefix_t prefix = {
     .fp_len = p_len,
     .fp_proto = FIB_PROTOCOL_IP4,
@@ -500,7 +664,7 @@ snat_add_del_addr_to_fib (ip4_address_t * addr, u8 p_len, u32 sw_if_index,
   if (is_add)
     fib_table_entry_update_one_path (fib_index,
                                     &prefix,
-                                    FIB_SOURCE_PLUGIN_LOW,
+                                    sm->fib_src_low,
                                     (FIB_ENTRY_FLAG_CONNECTED |
                                      FIB_ENTRY_FLAG_LOCAL |
                                      FIB_ENTRY_FLAG_EXCLUSIVE),
@@ -509,7 +673,7 @@ snat_add_del_addr_to_fib (ip4_address_t * addr, u8 p_len, u32 sw_if_index,
                                     sw_if_index,
                                     ~0, 1, NULL, FIB_ROUTE_PATH_FLAG_NONE);
   else
-    fib_table_entry_delete (fib_index, &prefix, FIB_SOURCE_PLUGIN_LOW);
+    fib_table_entry_delete (fib_index, &prefix, sm->fib_src_low);
 }
 
 int
@@ -521,14 +685,20 @@ snat_add_address (snat_main_t * sm, ip4_address_t * addr, u32 vrf_id,
   vlib_thread_main_t *tm = vlib_get_thread_main ();
 
   if (twice_nat && !sm->endpoint_dependent)
-    return VNET_API_ERROR_FEATURE_DISABLED;
+    {
+      nat_log_err ("unsupported");
+      return VNET_API_ERROR_UNSUPPORTED;
+    }
 
   /* Check if address already exists */
   /* *INDENT-OFF* */
   vec_foreach (ap, twice_nat ? sm->twice_nat_addresses : sm->addresses)
     {
       if (ap->addr.as_u32 == addr->as_u32)
-        return VNET_API_ERROR_VALUE_EXIST;
+        {
+          nat_log_err ("address exist");
+          return VNET_API_ERROR_VALUE_EXIST;
+        }
     }
   /* *INDENT-ON* */
 
@@ -541,17 +711,21 @@ snat_add_address (snat_main_t * sm, ip4_address_t * addr, u32 vrf_id,
   if (vrf_id != ~0)
     ap->fib_index =
       fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4, vrf_id,
-                                        FIB_SOURCE_PLUGIN_LOW);
+                                        sm->fib_src_low);
   else
     ap->fib_index = ~0;
-#define _(N, i, n, s) \
-  clib_bitmap_alloc (ap->busy_##n##_port_bitmap, 65535); \
-  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_snat_protocol
-#undef _
-    if (twice_nat)
+
+  /* *INDENT-OFF* */
+  #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 _
+  /* *INDENT-ON* */
+
+  if (twice_nat)
     return 0;
 
   /* Add external address to FIB */
@@ -596,15 +770,6 @@ is_snat_address_used_in_static_mapping (snat_main_t * sm, ip4_address_t addr)
   return 0;
 }
 
-void
-increment_v4_address (ip4_address_t * a)
-{
-  u32 v;
-
-  v = clib_net_to_host_u32 (a->as_u32) + 1;
-  a->as_u32 = clib_host_to_net_u32 (v);
-}
-
 static void
 snat_add_static_mapping_when_resolved (snat_main_t * sm,
                                       ip4_address_t l_addr,
@@ -612,10 +777,11 @@ snat_add_static_mapping_when_resolved (snat_main_t * sm,
                                       u32 sw_if_index,
                                       u16 e_port,
                                       u32 vrf_id,
-                                      snat_protocol_t proto,
+                                      nat_protocol_t proto,
                                       int addr_only, int is_add, u8 * tag,
                                       int twice_nat, int out2in_only,
-                                      int identity_nat)
+                                      int identity_nat,
+                                      ip4_address_t pool_addr, int exact)
 {
   snat_static_map_resolve_t *rp;
 
@@ -632,6 +798,8 @@ snat_add_static_mapping_when_resolved (snat_main_t * sm,
   rp->out2in_only = out2in_only;
   rp->identity_nat = identity_nat;
   rp->tag = vec_dup (tag);
+  rp->pool_addr = pool_addr;
+  rp->exact = exact;
 }
 
 static u32
@@ -648,16 +816,115 @@ get_thread_idx_by_port (u16 e_port)
   return thread_idx;
 }
 
-int
-snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
-                        u16 l_port, u16 e_port, u32 vrf_id, int addr_only,
-                        u32 sw_if_index, snat_protocol_t proto, int is_add,
-                        twice_nat_type_t twice_nat, u8 out2in_only, u8 * tag,
-                        u8 identity_nat)
+void
+nat_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,
+                                   ip4_address_t e_addr, u16 e_port)
 {
-  snat_main_t *sm = &snat_main;
-  snat_static_mapping_t *m;
-  snat_session_key_t m_key;
+  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;
+  u32 elt_index, head_index, ses_index;
+
+  if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
+    {
+      user_index = value.value;
+      u = pool_elt_at_index (tsm->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);
+         elt_index = head->next;
+         elt = pool_elt_at_index (tsm->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);
+             ses_index = elt->value;
+
+             if (!addr_only)
+               {
+                 if ((s->out2in.addr.as_u32 != e_addr.as_u32) ||
+                     (s->out2in.port != e_port))
+                   continue;
+               }
+
+             if (is_lb_session (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);
+
+             if (!addr_only)
+               break;
+           }
+       }
+    }
+}
+
+void
+nat_ed_static_mapping_del_sessions (snat_main_t * sm,
+                                   snat_main_per_thread_data_t * tsm,
+                                   ip4_address_t l_addr,
+                                   u16 l_port,
+                                   u8 protocol,
+                                   u32 fib_index, int addr_only,
+                                   ip4_address_t e_addr, u16 e_port)
+{
+  snat_session_t *s;
+  u32 *indexes_to_free = NULL;
+  /* *INDENT-OFF* */
+  pool_foreach (s, tsm->sessions, {
+    if (s->in2out.fib_index != fib_index ||
+        s->in2out.addr.as_u32 != l_addr.as_u32)
+      {
+        continue;
+      }
+    if (!addr_only)
+      {
+        if ((s->out2in.addr.as_u32 != e_addr.as_u32) ||
+            s->out2in.port != e_port ||
+            s->in2out.port != l_port ||
+            s->nat_proto != protocol)
+          continue;
+      }
+
+    if (is_lb_session (s))
+      continue;
+    if (!snat_is_session_static (s))
+      continue;
+    nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+    vec_add1 (indexes_to_free, s - tsm->sessions);
+    if (!addr_only)
+      break;
+  });
+  /* *INDENT-ON* */
+  u32 *ses_index;
+  vec_foreach (ses_index, indexes_to_free)
+  {
+    s = pool_elt_at_index (tsm->sessions, *ses_index);
+    nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
+  }
+  vec_free (indexes_to_free);
+}
+
+int
+snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
+                        u16 l_port, u16 e_port, u32 vrf_id, int addr_only,
+                        u32 sw_if_index, nat_protocol_t proto, int is_add,
+                        twice_nat_type_t twice_nat, u8 out2in_only, u8 * tag,
+                        u8 identity_nat, ip4_address_t pool_addr, int exact)
+{
+  snat_main_t *sm = &snat_main;
+  snat_static_mapping_t *m;
   clib_bihash_kv_8_8_t kv, value;
   snat_address_t *a = 0;
   u32 fib_index = ~0;
@@ -678,7 +945,7 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
   if (!sm->endpoint_dependent)
     {
       if (twice_nat || out2in_only)
-       return VNET_API_ERROR_FEATURE_DISABLED;
+       return VNET_API_ERROR_UNSUPPORTED;
     }
 
   /* If the external address is a specific interface address */
@@ -696,7 +963,7 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
          if (!addr_only)
            {
-             if (rp->l_port != l_port || rp->e_port != e_port
+             if ((rp->l_port != l_port && rp->e_port != e_port)
                  || rp->proto != proto)
                continue;
            }
@@ -716,7 +983,8 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
          snat_add_static_mapping_when_resolved
            (sm, l_addr, l_port, sw_if_index, e_port, vrf_id, proto,
-            addr_only, is_add, tag, twice_nat, out2in_only, identity_nat);
+            addr_only, is_add, tag, twice_nat, out2in_only,
+            identity_nat, pool_addr, exact);
 
          /* DHCP resolution required? */
          if (first_int_addr == 0)
@@ -750,11 +1018,7 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
        }
     }
 
-  m_key.addr = e_addr;
-  m_key.port = addr_only ? 0 : e_port;
-  m_key.protocol = addr_only ? 0 : proto;
-  m_key.fib_index = 0;
-  kv.key = m_key.as_u64;
+  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 = 0;
   else
@@ -777,13 +1041,10 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
              local->vrf_id = vrf_id;
              local->fib_index =
                fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4, vrf_id,
-                                                  FIB_SOURCE_PLUGIN_LOW);
-             m_key.addr = m->local_addr;
-             m_key.port = m->local_port;
-             m_key.protocol = m->proto;
-             m_key.fib_index = local->fib_index;
-             kv.key = m_key.as_u64;
-             kv.value = m - sm->static_mappings;
+                                                  sm->fib_src_low);
+             init_nat_kv (&kv, m->local_addr, m->local_port,
+                          local->fib_index, m->proto,
+                          m - sm->static_mappings);
              clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
              return 0;
            }
@@ -798,21 +1059,19 @@ snat_add_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,
-                                            FIB_SOURCE_PLUGIN_LOW);
+                                            sm->fib_src_low);
       /* If not specified use inside VRF id from SNAT plugin startup 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);
        }
 
       if (!(out2in_only || identity_nat))
        {
-         m_key.addr = l_addr;
-         m_key.port = addr_only ? 0 : l_port;
-         m_key.protocol = addr_only ? 0 : proto;
-         m_key.fib_index = fib_index;
-         kv.key = m_key.as_u64;
+         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, &value))
            return VNET_API_ERROR_VALUE_EXIST;
@@ -831,20 +1090,20 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
                  switch (proto)
                    {
 #define _(N, j, n, s) \
-                    case SNAT_PROTOCOL_##N: \
-                      if (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, e_port)) \
+                    case NAT_PROTOCOL_##N: \
+                      if (a->busy_##n##_port_refcounts[e_port]) \
                         return VNET_API_ERROR_INVALID_VALUE; \
-                      clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, e_port, 1); \
+                      ++a->busy_##n##_port_refcounts[e_port]; \
                       if (e_port > 1024) \
                         { \
                           a->busy_##n##_ports++; \
                           a->busy_##n##_ports_per_thread[get_thread_idx_by_port(e_port)]++; \
                         } \
                       break;
-                     foreach_snat_protocol
+                     foreach_nat_protocol
 #undef _
                    default:
-                     nat_log_info ("unknown protocol");
+                     nat_elog_info ("unknown protocol");
                      return VNET_API_ERROR_INVALID_VALUE_2;
                    }
                  break;
@@ -880,6 +1139,13 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       m->local_addr = l_addr;
       m->external_addr = e_addr;
       m->twice_nat = twice_nat;
+
+      if (twice_nat == TWICE_NAT && exact)
+       {
+         m->flags |= NAT_STATIC_MAPPING_FLAG_EXACT_ADDRESS;
+         m->pool_addr = pool_addr;
+       }
+
       if (out2in_only)
        m->flags |= NAT_STATIC_MAPPING_FLAG_OUT2IN_ONLY;
       if (addr_only)
@@ -908,29 +1174,23 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
          ip4_header_t ip = {
            .src_address = m->local_addr,
          };
-         vec_add1 (m->workers, sm->worker_in2out_cb (&ip, m->fib_index));
+         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]);
        }
       else
        tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
 
-      m_key.addr = m->local_addr;
-      m_key.port = m->local_port;
-      m_key.protocol = m->proto;
-      m_key.fib_index = fib_index;
-      kv.key = m_key.as_u64;
-      kv.value = m - sm->static_mappings;
+      init_nat_kv (&kv, m->local_addr, m->local_port, fib_index, m->proto,
+                  m - sm->static_mappings);
       if (!out2in_only)
        clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
 
-      m_key.addr = m->external_addr;
-      m_key.port = m->external_port;
-      m_key.fib_index = 0;
-      kv.key = m_key.as_u64;
-      kv.value = m - sm->static_mappings;
+      init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto,
+                  m - sm->static_mappings);
       clib_bihash_add_del_8_8 (&sm->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))
        {
          u_key.addr = m->local_addr;
@@ -956,13 +1216,11 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
                      if (snat_is_session_static (s))
                        continue;
 
-                     if (!addr_only
-                         && (clib_net_to_host_u16 (s->in2out.port) !=
-                             m->local_port))
+                     if (!addr_only && s->in2out.port != m->local_port)
                        continue;
 
                      nat_free_session_data (sm, s,
-                                            tsm - sm->per_thread_data);
+                                            tsm - sm->per_thread_data, 0);
                      nat44_delete_session (sm, s, tsm - sm->per_thread_data);
 
                      if (!addr_only && !sm->endpoint_dependent)
@@ -1015,18 +1273,18 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
                  switch (proto)
                    {
 #define _(N, j, n, s) \
-                    case SNAT_PROTOCOL_##N: \
-                      clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, e_port, 0); \
+                    case NAT_PROTOCOL_##N: \
+                      --a->busy_##n##_port_refcounts[e_port]; \
                       if (e_port > 1024) \
                         { \
                           a->busy_##n##_ports--; \
                           a->busy_##n##_ports_per_thread[get_thread_idx_by_port(e_port)]--; \
                         } \
                       break;
-                     foreach_snat_protocol
+                     foreach_nat_protocol
 #undef _
                    default:
-                     nat_log_info ("unknown protocol");
+                     nat_elog_info ("unknown protocol");
                      return VNET_API_ERROR_INVALID_VALUE_2;
                    }
                  break;
@@ -1039,11 +1297,7 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       else
        tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
 
-      m_key.addr = m->local_addr;
-      m_key.port = m->local_port;
-      m_key.protocol = m->proto;
-      m_key.fib_index = fib_index;
-      kv.key = m_key.as_u64;
+      init_nat_k (&kv, m->local_addr, m->local_port, fib_index, m->proto);
       if (!out2in_only)
        clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 0);
 
@@ -1051,59 +1305,28 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       if (!(sm->static_mapping_only) ||
          (sm->static_mapping_only && sm->static_mapping_connection_tracking))
        {
-         u_key.addr = m->local_addr;
-         u_key.fib_index = fib_index;
-         kv.key = u_key.as_u64;
-         if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
+         if (sm->endpoint_dependent)
            {
-             user_index = value.value;
-             u = pool_elt_at_index (tsm->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);
-                 elt_index = head->next;
-                 elt = pool_elt_at_index (tsm->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);
-                     ses_index = elt->value;
-
-                     if (!addr_only)
-                       {
-                         if ((s->out2in.addr.as_u32 != e_addr.as_u32) ||
-                             (clib_net_to_host_u16 (s->out2in.port) !=
-                              e_port))
-                           continue;
-                       }
-
-                     if (is_lb_session (s))
-                       continue;
-
-                     if (!snat_is_session_static (s))
-                       continue;
-
-                     nat_free_session_data (sm, s,
-                                            tsm - sm->per_thread_data);
-                     nat44_delete_session (sm, s, tsm - sm->per_thread_data);
-
-                     if (!addr_only && !sm->endpoint_dependent)
-                       break;
-                   }
-               }
+             nat_ed_static_mapping_del_sessions (sm, tsm, m->local_addr,
+                                                 m->local_port, m->proto,
+                                                 fib_index, addr_only,
+                                                 e_addr, e_port);
+           }
+         else
+           {
+             u_key.addr = m->local_addr;
+             u_key.fib_index = fib_index;
+             kv.key = u_key.as_u64;
+             nat_ei_static_mapping_del_sessions (sm, tsm, u_key, addr_only,
+                                                 e_addr, e_port);
            }
        }
 
-      fib_table_unlock (fib_index, FIB_PROTOCOL_IP4, FIB_SOURCE_PLUGIN_LOW);
+      fib_table_unlock (fib_index, FIB_PROTOCOL_IP4, sm->fib_src_low);
       if (pool_elts (m->locals))
        return 0;
 
-      m_key.addr = m->external_addr;
-      m_key.port = m->external_port;
-      m_key.fib_index = 0;
-      kv.key = m_key.as_u64;
+      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);
 
       vec_free (m->tag);
@@ -1140,34 +1363,25 @@ snat_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
 int
 nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
-                                snat_protocol_t proto,
+                                nat_protocol_t proto,
                                 nat44_lb_addr_port_t * locals, u8 is_add,
                                 twice_nat_type_t twice_nat, u8 out2in_only,
                                 u8 * tag, u32 affinity)
 {
   snat_main_t *sm = &snat_main;
   snat_static_mapping_t *m;
-  snat_session_key_t m_key;
   clib_bihash_kv_8_8_t kv, value;
   snat_address_t *a = 0;
   int i;
   nat44_lb_addr_port_t *local;
-  u32 elt_index, head_index, ses_index;
   snat_main_per_thread_data_t *tsm;
-  snat_user_key_t u_key;
-  snat_user_t *u;
   snat_session_t *s;
-  dlist_elt_t *head, *elt;
   uword *bitmap = 0;
 
   if (!sm->endpoint_dependent)
     return VNET_API_ERROR_FEATURE_DISABLED;
 
-  m_key.addr = e_addr;
-  m_key.port = e_port;
-  m_key.protocol = proto;
-  m_key.fib_index = 0;
-  kv.key = m_key.as_u64;
+  init_nat_k (&kv, e_addr, e_port, 0, proto);
   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
     m = 0;
   else
@@ -1194,20 +1408,20 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
                  switch (proto)
                    {
 #define _(N, j, n, s) \
-                    case SNAT_PROTOCOL_##N: \
-                      if (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, e_port)) \
+                    case NAT_PROTOCOL_##N: \
+                      if (a->busy_##n##_port_refcounts[e_port]) \
                         return VNET_API_ERROR_INVALID_VALUE; \
-                      clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, e_port, 1); \
+                      ++a->busy_##n##_port_refcounts[e_port]; \
                       if (e_port > 1024) \
                         { \
                           a->busy_##n##_ports++; \
                           a->busy_##n##_ports_per_thread[get_thread_idx_by_port(e_port)]++; \
                         } \
                       break;
-                     foreach_snat_protocol
+                     foreach_nat_protocol
 #undef _
                    default:
-                     nat_log_info ("unknown protocol");
+                     nat_elog_info ("unknown protocol");
                      return VNET_API_ERROR_INVALID_VALUE_2;
                    }
                  break;
@@ -1236,32 +1450,25 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       else
        m->affinity_per_service_list_head_index = ~0;
 
-      m_key.addr = m->external_addr;
-      m_key.port = m->external_port;
-      m_key.protocol = m->proto;
-      m_key.fib_index = 0;
-      kv.key = m_key.as_u64;
-      kv.value = m - sm->static_mappings;
+      init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto,
+                  m - sm->static_mappings);
       if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 1))
        {
-         nat_log_err ("static_mapping_by_external key add failed");
+         nat_elog_err ("static_mapping_by_external key add failed");
          return VNET_API_ERROR_UNSPECIFIED;
        }
 
-      m_key.fib_index = m->fib_index;
       for (i = 0; i < vec_len (locals); i++)
        {
          locals[i].fib_index =
            fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4,
                                               locals[i].vrf_id,
-                                              FIB_SOURCE_PLUGIN_LOW);
-         m_key.addr = locals[i].addr;
-         m_key.fib_index = locals[i].fib_index;
+                                              sm->fib_src_low);
          if (!out2in_only)
            {
-             m_key.port = locals[i].port;
-             kv.key = m_key.as_u64;
-             kv.value = m - sm->static_mappings;
+             init_nat_kv (&kv, locals[i].addr, locals[i].port,
+                          locals[i].fib_index, m->proto,
+                          m - sm->static_mappings);
              clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
            }
          locals[i].prefix = (i == 0) ? locals[i].probability :
@@ -1275,7 +1482,8 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
              };
              bitmap =
                clib_bitmap_set (bitmap,
-                                sm->worker_in2out_cb (&ip, m->fib_index), 1);
+                                sm->worker_in2out_cb (&ip, m->fib_index, 0),
+                                1);
            }
        }
 
@@ -1309,18 +1517,18 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
                  switch (proto)
                    {
 #define _(N, j, n, s) \
-                    case SNAT_PROTOCOL_##N: \
-                      clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, e_port, 0); \
+                    case NAT_PROTOCOL_##N: \
+                      --a->busy_##n##_port_refcounts[e_port]; \
                       if (e_port > 1024) \
                         { \
                           a->busy_##n##_ports--; \
                           a->busy_##n##_ports_per_thread[get_thread_idx_by_port(e_port)]--; \
                         } \
                       break;
-                     foreach_snat_protocol
+                     foreach_nat_protocol
 #undef _
                    default:
-                     nat_log_info ("unknown protocol");
+                     nat_elog_info ("unknown protocol");
                      return VNET_API_ERROR_INVALID_VALUE_2;
                    }
                  break;
@@ -1328,14 +1536,10 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
            }
        }
 
-      m_key.addr = m->external_addr;
-      m_key.port = m->external_port;
-      m_key.protocol = m->proto;
-      m_key.fib_index = 0;
-      kv.key = m_key.as_u64;
+      init_nat_k (&kv, m->external_addr, m->external_port, 0, m->proto);
       if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 0))
        {
-         nat_log_err ("static_mapping_by_external key del failed");
+         nat_elog_err ("static_mapping_by_external key del failed");
          return VNET_API_ERROR_UNSPECIFIED;
        }
 
@@ -1343,16 +1547,13 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       pool_foreach (local, m->locals,
       ({
           fib_table_unlock (local->fib_index, FIB_PROTOCOL_IP4,
-                            FIB_SOURCE_PLUGIN_LOW);
-          m_key.addr = local->addr;
+                            sm->fib_src_low);
           if (!out2in_only)
             {
-              m_key.port = local->port;
-              m_key.fib_index = local->fib_index;
-              kv.key = m_key.as_u64;
+init_nat_k(&              kv, local->addr, local->port, local->fib_index, m->proto);
               if (clib_bihash_add_del_8_8(&sm->static_mapping_by_local, &kv, 0))
                 {
-                  nat_log_err ("static_mapping_by_local key del failed");
+                  nat_elog_err ("static_mapping_by_local key del failed");
                   return VNET_API_ERROR_UNSPECIFIED;
                 }
             }
@@ -1363,43 +1564,23 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
                 .src_address = local->addr,
               };
               tsm = vec_elt_at_index (sm->per_thread_data,
-                                      sm->worker_in2out_cb (&ip, m->fib_index));
+                                      sm->worker_in2out_cb (&ip, m->fib_index, 0));
             }
           else
             tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
 
           /* Delete sessions */
-          u_key.addr = local->addr;
-          u_key.fib_index = local->fib_index;
-          kv.key = u_key.as_u64;
-          if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
-            {
-              u = pool_elt_at_index (tsm->users, value.value);
-              if (u->nstaticsessions)
-                {
-                  head_index = u->sessions_per_user_list_head_index;
-                  head = pool_elt_at_index (tsm->list_pool, head_index);
-                  elt_index = head->next;
-                  elt = pool_elt_at_index (tsm->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);
-                      ses_index = elt->value;
-
-                      if (!(is_lb_session (s)))
-                        continue;
-
-                      if ((s->in2out.addr.as_u32 != local->addr.as_u32) ||
-                          (clib_net_to_host_u16 (s->in2out.port) != local->port))
-                        continue;
-
-                      nat_free_session_data (sm, s, tsm - sm->per_thread_data);
-                      nat44_delete_session (sm, s, tsm - sm->per_thread_data);
-                    }
-                }
-            }
+          pool_foreach (s, tsm->sessions, {
+            if (!(is_lb_session (s)))
+              continue;
+
+            if ((s->in2out.addr.as_u32 != local->addr.as_u32) ||
+                s->in2out.port != local->port)
+              continue;
+
+            nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+            nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
+          });
       }));
       /* *INDENT-ON* */
       if (m->affinity)
@@ -1417,31 +1598,23 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 int
 nat44_lb_static_mapping_add_del_local (ip4_address_t e_addr, u16 e_port,
                                       ip4_address_t l_addr, u16 l_port,
-                                      snat_protocol_t proto, u32 vrf_id,
+                                      nat_protocol_t proto, u32 vrf_id,
                                       u8 probability, u8 is_add)
 {
   snat_main_t *sm = &snat_main;
   snat_static_mapping_t *m = 0;
-  snat_session_key_t m_key;
   clib_bihash_kv_8_8_t kv, value;
   nat44_lb_addr_port_t *local, *prev_local, *match_local = 0;
   snat_main_per_thread_data_t *tsm;
-  snat_user_key_t u_key;
-  snat_user_t *u;
   snat_session_t *s;
-  dlist_elt_t *head, *elt;
-  u32 elt_index, head_index, ses_index, *locals = 0;
+  u32 *locals = 0;
   uword *bitmap = 0;
   int i;
 
   if (!sm->endpoint_dependent)
     return VNET_API_ERROR_FEATURE_DISABLED;
 
-  m_key.addr = e_addr;
-  m_key.port = e_port;
-  m_key.protocol = proto;
-  m_key.fib_index = 0;
-  kv.key = m_key.as_u64;
+  init_nat_k (&kv, e_addr, e_port, 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);
 
@@ -1476,17 +1649,14 @@ nat44_lb_static_mapping_add_del_local (ip4_address_t e_addr, u16 e_port,
       local->vrf_id = vrf_id;
       local->fib_index =
        fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4, vrf_id,
-                                          FIB_SOURCE_PLUGIN_LOW);
+                                          sm->fib_src_low);
 
       if (!is_out2in_only_static_mapping (m))
        {
-         m_key.addr = l_addr;
-         m_key.port = l_port;
-         m_key.fib_index = local->fib_index;
-         kv.key = m_key.as_u64;
-         kv.value = m - sm->static_mappings;
+         init_nat_kv (&kv, l_addr, l_port, local->fib_index, proto,
+                      m - sm->static_mappings);
          if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1))
-           nat_log_err ("static_mapping_by_local key add failed");
+           nat_elog_err ("static_mapping_by_local key add failed");
        }
     }
   else
@@ -1498,16 +1668,13 @@ nat44_lb_static_mapping_add_del_local (ip4_address_t e_addr, u16 e_port,
        return VNET_API_ERROR_UNSPECIFIED;
 
       fib_table_unlock (match_local->fib_index, FIB_PROTOCOL_IP4,
-                       FIB_SOURCE_PLUGIN_LOW);
+                       sm->fib_src_low);
 
       if (!is_out2in_only_static_mapping (m))
        {
-         m_key.addr = l_addr;
-         m_key.port = l_port;
-         m_key.fib_index = match_local->fib_index;
-         kv.key = m_key.as_u64;
+         init_nat_k (&kv, l_addr, l_port, match_local->fib_index, proto);
          if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 0))
-           nat_log_err ("static_mapping_by_local key del failed");
+           nat_elog_err ("static_mapping_by_local key del failed");
        }
 
       if (sm->num_workers > 1)
@@ -1516,44 +1683,26 @@ nat44_lb_static_mapping_add_del_local (ip4_address_t e_addr, u16 e_port,
            .src_address = local->addr,
          };
          tsm = vec_elt_at_index (sm->per_thread_data,
-                                 sm->worker_in2out_cb (&ip, m->fib_index));
+                                 sm->worker_in2out_cb (&ip, m->fib_index,
+                                                       0));
        }
       else
        tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
 
       /* Delete sessions */
-      u_key.addr = match_local->addr;
-      u_key.fib_index = match_local->fib_index;
-      kv.key = u_key.as_u64;
-      if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
-       {
-         u = pool_elt_at_index (tsm->users, value.value);
-         if (u->nstaticsessions)
-           {
-             head_index = u->sessions_per_user_list_head_index;
-             head = pool_elt_at_index (tsm->list_pool, head_index);
-             elt_index = head->next;
-             elt = pool_elt_at_index (tsm->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);
-                 ses_index = elt->value;
-
-                 if (!(is_lb_session (s)))
-                   continue;
+      /* *INDENT-OFF* */
+      pool_foreach (s, tsm->sessions, {
+        if (!(is_lb_session (s)))
+          continue;
 
-                 if ((s->in2out.addr.as_u32 != match_local->addr.as_u32) ||
-                     (clib_net_to_host_u16 (s->in2out.port) !=
-                      match_local->port))
-                   continue;
+        if ((s->in2out.addr.as_u32 != match_local->addr.as_u32) ||
+            s->in2out.port != match_local->port)
+          continue;
 
-                 nat_free_session_data (sm, s, tsm - sm->per_thread_data);
-                 nat44_delete_session (sm, s, tsm - sm->per_thread_data);
-               }
-           }
-       }
+        nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+        nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
+      });
+      /* *INDENT-ON* */
 
       pool_put (m->locals, match_local);
     }
@@ -1569,7 +1718,7 @@ nat44_lb_static_mapping_add_del_local (ip4_address_t e_addr, u16 e_port,
         ip4_header_t ip;
         ip.src_address.as_u32 = local->addr.as_u32,
         bitmap = clib_bitmap_set (bitmap,
-                                  sm->worker_in2out_cb (&ip, local->fib_index),
+                                  sm->worker_in2out_cb (&ip, local->fib_index, 0),
                                   1);
       }
   }));
@@ -1621,19 +1770,28 @@ snat_del_address (snat_main_t * sm, ip4_address_t addr, u8 delete_sm,
        }
     }
   if (!a)
-    return VNET_API_ERROR_NO_SUCH_ENTRY;
+    {
+      nat_log_err ("no such address");
+      return VNET_API_ERROR_NO_SUCH_ENTRY;
+    }
 
   if (delete_sm)
     {
+      ip4_address_t pool_addr = { 0 };
       /* *INDENT-OFF* */
       pool_foreach (m, sm->static_mappings,
       ({
           if (m->external_addr.as_u32 == addr.as_u32)
             (void) snat_add_static_mapping (m->local_addr, m->external_addr,
                                             m->local_port, m->external_port,
-                                            m->vrf_id, is_addr_only_static_mapping(m), ~0,
-                                            m->proto, 0, m->twice_nat,
-                                            is_out2in_only_static_mapping(m), m->tag, is_identity_static_mapping(m));
+                                            m->vrf_id,
+                                            is_addr_only_static_mapping(m), ~0,
+                                            m->proto, 0 /* is_add */,
+                                            m->twice_nat,
+                                            is_out2in_only_static_mapping(m),
+                                            m->tag,
+                                            is_identity_static_mapping(m),
+                                            pool_addr, 0);
       }));
       /* *INDENT-ON* */
     }
@@ -1642,43 +1800,53 @@ snat_del_address (snat_main_t * sm, ip4_address_t addr, u8 delete_sm,
       /* Check if address is used in some static mapping */
       if (is_snat_address_used_in_static_mapping (sm, addr))
        {
-         nat_log_notice ("address used in static mapping");
+         nat_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, FIB_SOURCE_PLUGIN_LOW);
+    fib_table_unlock (a->fib_index, FIB_PROTOCOL_IP4, sm->fib_src_low);
 
   /* Delete sessions using address */
   if (a->busy_tcp_ports || a->busy_udp_ports || a->busy_icmp_ports)
     {
-      /* *INDENT-OFF* */
       vec_foreach (tsm, sm->per_thread_data)
-        {
-          pool_foreach (ses, tsm->sessions, ({
-            if (ses->out2in.addr.as_u32 == addr.as_u32)
-              {
-                nat_free_session_data (sm, ses, tsm - sm->per_thread_data);
-                vec_add1 (ses_to_be_removed, ses - tsm->sessions);
-              }
-          }));
-
-          vec_foreach (ses_index, ses_to_be_removed)
+      {
+        /* *INDENT-OFF* */
+        pool_foreach (ses, tsm->sessions, ({
+          if (ses->out2in.addr.as_u32 == addr.as_u32)
             {
-              ses = pool_elt_at_index (tsm->sessions, ses_index[0]);
-              nat44_delete_session (sm, ses, tsm - sm->per_thread_data);
+              nat_free_session_data (sm, ses, tsm - sm->per_thread_data, 0);
+              vec_add1 (ses_to_be_removed, ses - tsm->sessions);
             }
+        }));
+        /* *INDENT-ON* */
 
-          vec_free (ses_to_be_removed);
-        }
-      /* *INDENT-ON* */
+       if (sm->endpoint_dependent)
+         {
+           vec_foreach (ses_index, ses_to_be_removed)
+           {
+             ses = pool_elt_at_index (tsm->sessions, ses_index[0]);
+             nat_ed_session_delete (sm, ses, tsm - sm->per_thread_data, 1);
+           }
+         }
+       else
+         {
+           vec_foreach (ses_index, ses_to_be_removed)
+           {
+             ses = pool_elt_at_index (tsm->sessions, ses_index[0]);
+             nat44_delete_session (sm, ses, tsm - sm->per_thread_data);
+           }
+         }
+
+       vec_free (ses_to_be_removed);
+      }
     }
 
 #define _(N, i, n, s) \
-  clib_bitmap_free (a->busy_##n##_port_bitmap); \
   vec_free (a->busy_##n##_ports_per_thread);
-  foreach_snat_protocol
+  foreach_nat_protocol
 #undef _
     if (twice_nat)
     {
@@ -1711,6 +1879,99 @@ snat_del_address (snat_main_t * sm, ip4_address_t addr, u8 delete_sm,
   return 0;
 }
 
+static void
+nat_validate_counters (snat_main_t * sm, u32 sw_if_index)
+{
+#define _(x)                                                                  \
+  vlib_validate_simple_counter (&sm->counters.fastpath.in2out.x,              \
+                                sw_if_index);                                 \
+  vlib_zero_simple_counter (&sm->counters.fastpath.in2out.x, sw_if_index);    \
+  vlib_validate_simple_counter (&sm->counters.fastpath.out2in.x,              \
+                                sw_if_index);                                 \
+  vlib_zero_simple_counter (&sm->counters.fastpath.out2in.x, sw_if_index);    \
+  vlib_validate_simple_counter (&sm->counters.slowpath.in2out.x,              \
+                                sw_if_index);                                 \
+  vlib_zero_simple_counter (&sm->counters.slowpath.in2out.x, sw_if_index);    \
+  vlib_validate_simple_counter (&sm->counters.slowpath.out2in.x,              \
+                                sw_if_index);                                 \
+  vlib_zero_simple_counter (&sm->counters.slowpath.out2in.x, sw_if_index);    \
+  vlib_validate_simple_counter (&sm->counters.fastpath.in2out_ed.x,           \
+                                sw_if_index);                                 \
+  vlib_zero_simple_counter (&sm->counters.fastpath.in2out_ed.x, sw_if_index); \
+  vlib_validate_simple_counter (&sm->counters.fastpath.out2in_ed.x,           \
+                                sw_if_index);                                 \
+  vlib_zero_simple_counter (&sm->counters.fastpath.out2in_ed.x, sw_if_index); \
+  vlib_validate_simple_counter (&sm->counters.slowpath.in2out_ed.x,           \
+                                sw_if_index);                                 \
+  vlib_zero_simple_counter (&sm->counters.slowpath.in2out_ed.x, sw_if_index); \
+  vlib_validate_simple_counter (&sm->counters.slowpath.out2in_ed.x,           \
+                                sw_if_index);                                 \
+  vlib_zero_simple_counter (&sm->counters.slowpath.out2in_ed.x, sw_if_index);
+  foreach_nat_counter;
+#undef _
+  vlib_validate_simple_counter (&sm->counters.hairpinning, sw_if_index);
+  vlib_zero_simple_counter (&sm->counters.hairpinning, sw_if_index);
+}
+
+void
+expire_per_vrf_sessions (u32 fib_index)
+{
+  per_vrf_sessions_t *per_vrf_sessions;
+  snat_main_per_thread_data_t *tsm;
+  snat_main_t *sm = &snat_main;
+
+  /* *INDENT-OFF* */
+  vec_foreach (tsm, sm->per_thread_data)
+    {
+      vec_foreach (per_vrf_sessions, tsm->per_vrf_sessions_vec)
+        {
+          if ((per_vrf_sessions->rx_fib_index == fib_index) ||
+              (per_vrf_sessions->tx_fib_index == fib_index))
+            {
+              per_vrf_sessions->expired = 1;
+            }
+        }
+    }
+  /* *INDENT-ON* */
+}
+
+void
+update_per_vrf_sessions_vec (u32 fib_index, int is_del)
+{
+  snat_main_t *sm = &snat_main;
+  nat_fib_t *fib;
+
+  // we don't care if it is outside/inside fib
+  // we just care about their ref_count
+  // if it reaches 0 sessions should expire
+  // because the fib isn't valid for NAT anymore
+
+  vec_foreach (fib, sm->fibs)
+  {
+    if (fib->fib_index == fib_index)
+      {
+       if (is_del)
+         {
+           fib->ref_count--;
+           if (!fib->ref_count)
+             {
+               vec_del1 (sm->fibs, fib - sm->fibs);
+               expire_per_vrf_sessions (fib_index);
+             }
+           return;
+         }
+       else
+         fib->ref_count++;
+      }
+  }
+  if (!is_del)
+    {
+      vec_add2 (sm->fibs, fib, 1);
+      fib->ref_count = 1;
+      fib->fib_index = fib_index;
+    }
+}
+
 int
 snat_interface_add_del (u32 sw_if_index, u8 is_inside, int is_del)
 {
@@ -1719,19 +1980,30 @@ snat_interface_add_del (u32 sw_if_index, u8 is_inside, int is_del)
   const char *feature_name, *del_feature_name;
   snat_address_t *ap;
   snat_static_mapping_t *m;
-  snat_det_map_t *dm;
   nat_outside_fib_t *outside_fib;
   u32 fib_index = fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
                                                       sw_if_index);
 
+  if (!sm->enabled)
+    {
+      nat_log_err ("nat44 is disabled");
+      return VNET_API_ERROR_UNSUPPORTED;
+    }
+
   if (sm->out2in_dpo && !is_inside)
-    return VNET_API_ERROR_UNSUPPORTED;
+    {
+      nat_log_err ("error unsupported");
+      return VNET_API_ERROR_UNSUPPORTED;
+    }
 
   /* *INDENT-OFF* */
   pool_foreach (i, sm->output_feature_interfaces,
   ({
     if (i->sw_if_index == sw_if_index)
-      return VNET_API_ERROR_VALUE_EXIST;
+      {
+        nat_log_err ("error interface already configured");
+        return VNET_API_ERROR_VALUE_EXIST;
+      }
   }));
   /* *INDENT-ON* */
 
@@ -1739,25 +2011,28 @@ snat_interface_add_del (u32 sw_if_index, u8 is_inside, int is_del)
     feature_name = is_inside ? "nat44-in2out-fast" : "nat44-out2in-fast";
   else
     {
-      if (sm->num_workers > 1 && !sm->deterministic)
+      if (sm->num_workers > 1)
        feature_name =
          is_inside ? "nat44-in2out-worker-handoff" :
          "nat44-out2in-worker-handoff";
-      else if (sm->deterministic)
-       feature_name = is_inside ? "nat44-det-in2out" : "nat44-det-out2in";
       else if (sm->endpoint_dependent)
-       feature_name = is_inside ? "nat44-ed-in2out" : "nat44-ed-out2in";
+       {
+         feature_name = is_inside ? "nat-pre-in2out" : "nat-pre-out2in";
+       }
       else
        feature_name = is_inside ? "nat44-in2out" : "nat44-out2in";
     }
 
-  if (sm->fq_in2out_index == ~0 && !sm->deterministic && sm->num_workers > 1)
-    sm->fq_in2out_index = vlib_frame_queue_main_init (sm->in2out_node_index,
-                                                     NAT_FQ_NELTS);
+  if (sm->fq_in2out_index == ~0 && sm->num_workers > 1)
+    sm->fq_in2out_index =
+      vlib_frame_queue_main_init (sm->in2out_node_index, NAT_FQ_NELTS);
+
+  if (sm->fq_out2in_index == ~0 && sm->num_workers > 1)
+    sm->fq_out2in_index =
+      vlib_frame_queue_main_init (sm->out2in_node_index, NAT_FQ_NELTS);
 
-  if (sm->fq_out2in_index == ~0 && !sm->deterministic && sm->num_workers > 1)
-    sm->fq_out2in_index = vlib_frame_queue_main_init (sm->out2in_node_index,
-                                                     NAT_FQ_NELTS);
+  if (sm->endpoint_dependent)
+    update_per_vrf_sessions_vec (fib_index, is_del);
 
   if (!is_inside)
     {
@@ -1768,7 +2043,7 @@ snat_interface_add_del (u32 sw_if_index, u8 is_inside, int is_del)
             {
               if (is_del)
                 {
-                  outside_fib->refcount--;
+                 outside_fib->refcount--;
                   if (!outside_fib->refcount)
                     vec_del1 (sm->outside_fibs, outside_fib - sm->outside_fibs);
                 }
@@ -1785,6 +2060,7 @@ snat_interface_add_del (u32 sw_if_index, u8 is_inside, int is_del)
          outside_fib->fib_index = fib_index;
        }
     }
+
 feature_set:
   /* *INDENT-OFF* */
   pool_foreach (i, sm->interfaces,
@@ -1800,23 +2076,17 @@ feature_set:
                 else
                   i->flags &= ~NAT_INTERFACE_FLAG_IS_OUTSIDE;
 
-                if (sm->num_workers > 1 && !sm->deterministic)
+                if (sm->num_workers > 1)
                   {
                     del_feature_name = "nat44-handoff-classify";
                     feature_name = !is_inside ?  "nat44-in2out-worker-handoff" :
                                                  "nat44-out2in-worker-handoff";
                   }
-                else if (sm->deterministic)
-                  {
-                    del_feature_name = "nat44-det-classify";
-                    feature_name = !is_inside ?  "nat44-det-in2out" :
-                                                 "nat44-det-out2in";
-                  }
                 else if (sm->endpoint_dependent)
                   {
                     del_feature_name = "nat44-ed-classify";
-                    feature_name = !is_inside ?  "nat44-ed-in2out" :
-                                                 "nat44-ed-out2in";
+                    feature_name = !is_inside ?  "nat-pre-in2out" :
+                                                 "nat-pre-out2in";
                   }
                 else
                   {
@@ -1824,6 +2094,9 @@ feature_set:
                     feature_name = !is_inside ?  "nat44-in2out" : "nat44-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,
@@ -1834,7 +2107,7 @@ feature_set:
                       vnet_feature_enable_disable ("ip4-local",
                                                    "nat44-ed-hairpinning",
                                                    sw_if_index, 1, 0, 0);
-                    else if (!sm->deterministic)
+                    else
                       vnet_feature_enable_disable ("ip4-local",
                                                    "nat44-hairpinning",
                                                    sw_if_index, 1, 0, 0);
@@ -1842,6 +2115,9 @@ feature_set:
               }
             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 (sm->interfaces, i);
@@ -1851,7 +2127,7 @@ feature_set:
                       vnet_feature_enable_disable ("ip4-local",
                                                    "nat44-ed-hairpinning",
                                                    sw_if_index, 0, 0, 0);
-                    else if (!sm->deterministic)
+                    else
                       vnet_feature_enable_disable ("ip4-local",
                                                    "nat44-hairpinning",
                                                    sw_if_index, 0, 0, 0);
@@ -1864,22 +2140,17 @@ feature_set:
                 (nat_interface_is_outside(i) && !is_inside))
               return 0;
 
-            if (sm->num_workers > 1 && !sm->deterministic)
+            if (sm->num_workers > 1)
               {
                 del_feature_name = !is_inside ?  "nat44-in2out-worker-handoff" :
                                                  "nat44-out2in-worker-handoff";
                 feature_name = "nat44-handoff-classify";
               }
-            else if (sm->deterministic)
-              {
-                del_feature_name = !is_inside ?  "nat44-det-in2out" :
-                                                 "nat44-det-out2in";
-                feature_name = "nat44-det-classify";
-              }
             else if (sm->endpoint_dependent)
               {
-                del_feature_name = !is_inside ?  "nat44-ed-in2out" :
-                                                 "nat44-ed-out2in";
+                del_feature_name = !is_inside ?  "nat-pre-in2out" :
+                                                 "nat-pre-out2in";
+
                 feature_name = "nat44-ed-classify";
               }
             else
@@ -1888,6 +2159,9 @@ feature_set:
                 feature_name = "nat44-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,
@@ -1897,7 +2171,7 @@ feature_set:
                 if (sm->endpoint_dependent)
                   vnet_feature_enable_disable ("ip4-local", "nat44-ed-hairpinning",
                                                sw_if_index, 0, 0, 0);
-                else if (!sm->deterministic)
+                else
                   vnet_feature_enable_disable ("ip4-local", "nat44-hairpinning",
                                                sw_if_index, 0, 0, 0);
               }
@@ -1910,20 +2184,29 @@ feature_set:
   /* *INDENT-ON* */
 
   if (is_del)
-    return VNET_API_ERROR_NO_SUCH_ENTRY;
+    {
+      nat_log_err ("error interface couldn't be found");
+      return VNET_API_ERROR_NO_SUCH_ENTRY;
+    }
 
   pool_get (sm->interfaces, i);
   i->sw_if_index = sw_if_index;
   i->flags = 0;
+  nat_validate_counters (sm, 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 && !sm->out2in_dpo)
     {
       if (sm->endpoint_dependent)
        vnet_feature_enable_disable ("ip4-local", "nat44-ed-hairpinning",
                                     sw_if_index, 1, 0, 0);
-      else if (!sm->deterministic)
+      else
        vnet_feature_enable_disable ("ip4-local", "nat44-hairpinning",
                                     sw_if_index, 1, 0, 0);
     }
@@ -1950,11 +2233,6 @@ fib:
 
     snat_add_del_addr_to_fib(&m->external_addr, 32, sw_if_index, !is_del);
   }));
-
-  pool_foreach (dm, sm->det_maps,
-  ({
-    snat_add_del_addr_to_fib(&dm->out_addr, dm->out_plen, sw_if_index, !is_del);
-  }));
   /* *INDENT-ON* */
 
   return 0;
@@ -1968,23 +2246,77 @@ snat_interface_add_del_output_feature (u32 sw_if_index,
   snat_interface_t *i;
   snat_address_t *ap;
   snat_static_mapping_t *m;
+  nat_outside_fib_t *outside_fib;
+  u32 fib_index = fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
+                                                      sw_if_index);
 
-  if (sm->deterministic ||
-      (sm->static_mapping_only && !(sm->static_mapping_connection_tracking)))
-    return VNET_API_ERROR_UNSUPPORTED;
+  if (!sm->enabled)
+    {
+      nat_log_err ("nat44 is disabled");
+      return VNET_API_ERROR_UNSUPPORTED;
+    }
+
+  if (sm->static_mapping_only && !(sm->static_mapping_connection_tracking))
+    {
+      nat_log_err ("error unsupported");
+      return VNET_API_ERROR_UNSUPPORTED;
+    }
 
   /* *INDENT-OFF* */
   pool_foreach (i, sm->interfaces,
   ({
     if (i->sw_if_index == sw_if_index)
-      return VNET_API_ERROR_VALUE_EXIST;
+      {
+        nat_log_err ("error interface already configured");
+        return VNET_API_ERROR_VALUE_EXIST;
+      }
   }));
   /* *INDENT-ON* */
 
+  if (sm->endpoint_dependent)
+    update_per_vrf_sessions_vec (fib_index, is_del);
+
+  if (!is_inside)
+    {
+      /* *INDENT-OFF* */
+      vec_foreach (outside_fib, sm->outside_fibs)
+        {
+          if (outside_fib->fib_index == fib_index)
+            {
+              if (is_del)
+                {
+                 outside_fib->refcount--;
+                  if (!outside_fib->refcount)
+                    vec_del1 (sm->outside_fibs, outside_fib - sm->outside_fibs);
+                }
+              else
+                outside_fib->refcount++;
+              goto feature_set;
+            }
+        }
+      /* *INDENT-ON* */
+      if (!is_del)
+       {
+         vec_add2 (sm->outside_fibs, outside_fib, 1);
+         outside_fib->refcount = 1;
+         outside_fib->fib_index = fib_index;
+       }
+    }
+
+feature_set:
   if (is_inside)
     {
       if (sm->endpoint_dependent)
        {
+         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-ed-hairpin-dst",
                                       sw_if_index, !is_del, 0, 0);
          vnet_feature_enable_disable ("ip4-output", "nat44-ed-hairpin-src",
@@ -1992,6 +2324,15 @@ snat_interface_add_del_output_feature (u32 sw_if_index,
        }
       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-hairpin-dst",
                                       sw_if_index, !is_del, 0, 0);
          vnet_feature_enable_disable ("ip4-output", "nat44-hairpin-src",
@@ -2002,6 +2343,13 @@ snat_interface_add_del_output_feature (u32 sw_if_index,
 
   if (sm->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-out2in-worker-handoff",
                                   sw_if_index, !is_del, 0, 0);
@@ -2013,13 +2361,31 @@ snat_interface_add_del_output_feature (u32 sw_if_index,
     {
       if (sm->endpoint_dependent)
        {
-         vnet_feature_enable_disable ("ip4-unicast", "nat44-ed-out2in",
+         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", "nat-pre-out2in",
                                       sw_if_index, !is_del, 0, 0);
-         vnet_feature_enable_disable ("ip4-output", "nat44-ed-in2out-output",
+         vnet_feature_enable_disable ("ip4-output", "nat-pre-in2out-output",
                                       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-out2in",
                                       sw_if_index, !is_del, 0, 0);
          vnet_feature_enable_disable ("ip4-output", "nat44-in2out-output",
@@ -2052,11 +2418,15 @@ fq:
   /* *INDENT-ON* */
 
   if (is_del)
-    return VNET_API_ERROR_NO_SUCH_ENTRY;
+    {
+      nat_log_err ("error interface couldn't be found");
+      return VNET_API_ERROR_NO_SUCH_ENTRY;
+    }
 
   pool_get (sm->output_feature_interfaces, i);
   i->sw_if_index = sw_if_index;
   i->flags = 0;
+  nat_validate_counters (sm, sw_if_index);
   if (is_inside)
     i->flags |= NAT_INTERFACE_FLAG_IS_INSIDE;
   else
@@ -2101,78 +2471,318 @@ snat_set_workers (uword * bitmap)
     ({
       vec_add1(sm->workers, i);
       sm->per_thread_data[sm->first_worker_index + i].snat_thread_index = j;
+      sm->per_thread_data[sm->first_worker_index + i].thread_index = i;
       j++;
     }));
   /* *INDENT-ON* */
 
   sm->port_per_thread = (0xffff - 1024) / _vec_len (sm->workers);
-  sm->num_snat_thread = _vec_len (sm->workers);
 
   return 0;
 }
 
-
 static void
-snat_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);
+snat_update_outside_fib (ip4_main_t * im, uword opaque,
+                        u32 sw_if_index, u32 new_fib_index,
+                        u32 old_fib_index)
+{
+  snat_main_t *sm = &snat_main;
+  nat_outside_fib_t *outside_fib;
+  snat_interface_t *i;
+  u8 is_add = 1;
+  u8 match = 0;
 
-static void
-nat_ip4_add_del_addr_only_sm_cb (ip4_main_t * im,
-                                uword opaque,
-                                u32 sw_if_index,
-                                ip4_address_t * address,
+  if (!sm->enabled || (new_fib_index == old_fib_index)
+      || (!vec_len (sm->outside_fibs)))
+    {
+      return;
+    }
+
+  /* *INDENT-OFF* */
+  pool_foreach (i, sm->interfaces,
+    ({
+      if (i->sw_if_index == sw_if_index)
+        {
+          if (!(nat_interface_is_outside (i)))
+           return;
+          match = 1;
+        }
+    }));
+
+  pool_foreach (i, sm->output_feature_interfaces,
+    ({
+      if (i->sw_if_index == sw_if_index)
+        {
+          if (!(nat_interface_is_outside (i)))
+           return;
+          match = 1;
+        }
+    }));
+  /* *INDENT-ON* */
+
+  if (!match)
+    return;
+
+  vec_foreach (outside_fib, sm->outside_fibs)
+  {
+    if (outside_fib->fib_index == old_fib_index)
+      {
+       outside_fib->refcount--;
+       if (!outside_fib->refcount)
+         vec_del1 (sm->outside_fibs, outside_fib - sm->outside_fibs);
+       break;
+      }
+  }
+
+  vec_foreach (outside_fib, sm->outside_fibs)
+  {
+    if (outside_fib->fib_index == new_fib_index)
+      {
+       outside_fib->refcount++;
+       is_add = 0;
+       break;
+      }
+  }
+
+  if (is_add)
+    {
+      vec_add2 (sm->outside_fibs, outside_fib, 1);
+      outside_fib->refcount = 1;
+      outside_fib->fib_index = new_fib_index;
+    }
+}
+
+static void
+snat_update_outside_fib (ip4_main_t * im, uword opaque,
+                        u32 sw_if_index, u32 new_fib_index,
+                        u32 old_fib_index);
+
+static void
+snat_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
+nat_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 int
-nat_alloc_addr_and_port_default (snat_address_t * addresses,
-                                u32 fib_index,
-                                u32 thread_index,
-                                snat_session_key_t * k,
+nat_alloc_addr_and_port_default (snat_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);
 
+void
+test_key_calc_split ()
+{
+  ip4_address_t l_addr;
+  l_addr.as_u8[0] = 1;
+  l_addr.as_u8[1] = 1;
+  l_addr.as_u8[2] = 1;
+  l_addr.as_u8[3] = 1;
+  ip4_address_t r_addr;
+  r_addr.as_u8[0] = 2;
+  r_addr.as_u8[1] = 2;
+  r_addr.as_u8[2] = 2;
+  r_addr.as_u8[3] = 2;
+  u16 l_port = 40001;
+  u16 r_port = 40301;
+  u8 proto = 9;
+  u32 fib_index = 9000001;
+  u32 thread_index = 3000000001;
+  u32 session_index = 3000000221;
+  clib_bihash_kv_16_8_t kv;
+  init_ed_kv (&kv, l_addr, l_port, r_addr, r_port, fib_index, proto,
+             thread_index, session_index);
+  ip4_address_t l_addr2;
+  ip4_address_t r_addr2;
+  clib_memset (&l_addr2, 0, sizeof (l_addr2));
+  clib_memset (&r_addr2, 0, sizeof (r_addr2));
+  u16 l_port2 = 0;
+  u16 r_port2 = 0;
+  u8 proto2 = 0;
+  u32 fib_index2 = 0;
+  split_ed_kv (&kv, &l_addr2, &r_addr2, &proto2, &fib_index2, &l_port2,
+              &r_port2);
+  ASSERT (l_addr.as_u32 == l_addr2.as_u32);
+  ASSERT (r_addr.as_u32 == r_addr2.as_u32);
+  ASSERT (l_port == l_port2);
+  ASSERT (r_port == r_port2);
+  ASSERT (proto == proto2);
+  ASSERT (fib_index == fib_index2);
+  ASSERT (thread_index == ed_value_get_thread_index (&kv));
+  ASSERT (session_index == ed_value_get_session_index (&kv));
+
+  fib_index = 7001;
+  proto = 5;
+  nat_protocol_t proto3 = ~0;
+  u64 key = calc_nat_key (l_addr, l_port, fib_index, proto);
+  split_nat_key (key, &l_addr2, &l_port2, &fib_index2, &proto3);
+  ASSERT (l_addr.as_u32 == l_addr2.as_u32);
+  ASSERT (l_port == l_port2);
+  ASSERT (proto == proto3);
+  ASSERT (fib_index == fib_index2);
+}
+
 static clib_error_t *
-snat_init (vlib_main_t * vm)
+nat_ip_table_add_del (vnet_main_t * vnm, u32 table_id, u32 is_add)
+{
+  snat_main_t *sm = &snat_main;
+  u32 fib_index;
+
+  if (sm->endpoint_dependent)
+    {
+      // TODO: consider removing all NAT interfaces
+      if (!is_add)
+       {
+         fib_index = ip4_fib_index_from_table_id (table_id);
+         if (fib_index != ~0)
+           expire_per_vrf_sessions (fib_index);
+       }
+    }
+  return 0;
+}
+
+VNET_IP_TABLE_ADD_DEL_FUNCTION (nat_ip_table_add_del);
+
+void
+nat44_set_node_indexes (snat_main_t * sm, vlib_main_t * vm)
+{
+  vlib_node_t *node;
+
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-out2in");
+  sm->ei_out2in_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-in2out");
+  sm->ei_in2out_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-in2out-output");
+  sm->ei_in2out_output_node_index = node->index;
+
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ed-out2in");
+  sm->ed_out2in_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ed-in2out");
+  sm->ed_in2out_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ed-in2out-output");
+  sm->ed_in2out_output_node_index = node->index;
+
+  node = vlib_get_node_by_name (vm, (u8 *) "error-drop");
+  sm->error_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat-pre-in2out");
+  sm->pre_in2out_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat-pre-out2in");
+  sm->pre_out2in_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat-pre-in2out");
+  sm->pre_in2out_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat-pre-out2in");
+  sm->pre_out2in_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-in2out-fast");
+  sm->in2out_fast_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-in2out-slowpath");
+  sm->in2out_slowpath_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-in2out-output-slowpath");
+  sm->in2out_slowpath_output_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ed-in2out-slowpath");
+  sm->ed_in2out_slowpath_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-out2in-fast");
+  sm->out2in_fast_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ed-out2in-slowpath");
+  sm->ed_out2in_slowpath_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-hairpinning");
+  sm->hairpinning_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-hairpin-dst");
+  sm->hairpin_dst_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-hairpin-src");
+  sm->hairpin_src_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ed-hairpinning");
+  sm->ed_hairpinning_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ed-hairpin-dst");
+  sm->ed_hairpin_dst_node_index = node->index;
+  node = vlib_get_node_by_name (vm, (u8 *) "nat44-ed-hairpin-src");
+  sm->ed_hairpin_src_node_index = node->index;
+}
+
+#define nat_init_simple_counter(c, n, sn) \
+do                                        \
+  {                                       \
+    c.name = n;                           \
+    c.stat_segment_name = sn;             \
+    vlib_validate_simple_counter (&c, 0); \
+    vlib_zero_simple_counter (&c, 0);     \
+  } while (0);
+
+static clib_error_t *
+nat_init (vlib_main_t * vm)
 {
   snat_main_t *sm = &snat_main;
-  clib_error_t *error = 0;
-  ip4_main_t *im = &ip4_main;
-  ip_lookup_main_t *lm = &im->lookup_main;
-  uword *p;
-  vlib_thread_registration_t *tr;
   vlib_thread_main_t *tm = vlib_get_thread_main ();
-  uword *bitmap = 0;
-  u32 i;
-  ip4_add_del_interface_address_callback_t cb4;
-  vlib_node_t *error_drop_node;
+  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 (sm, 0, sizeof (*sm));
 
-  sm->vlib_main = vm;
+  // required
   sm->vnet_main = vnet_get_main ();
-  sm->ip4_main = im;
-  sm->ip4_lookup_main = lm;
-  sm->api_main = &api_main;
-  sm->first_worker_index = 0;
-  sm->num_workers = 0;
-  sm->num_snat_thread = 1;
-  sm->workers = 0;
-  sm->port_per_thread = 0xffff - 1024;
-  sm->fq_in2out_index = ~0;
+  // convenience
+  sm->ip4_main = &ip4_main;
+  sm->api_main = vlibapi_get_main ();
+  sm->ip4_lookup_main = &ip4_main.lookup_main;
+
+  // frame queue indices used for handoff
   sm->fq_out2in_index = ~0;
-  sm->udp_timeout = SNAT_UDP_TIMEOUT;
-  sm->tcp_established_timeout = SNAT_TCP_ESTABLISHED_TIMEOUT;
-  sm->tcp_transitory_timeout = SNAT_TCP_TRANSITORY_TIMEOUT;
-  sm->icmp_timeout = SNAT_ICMP_TIMEOUT;
-  sm->alloc_addr_and_port = nat_alloc_addr_and_port_default;
-  sm->addr_and_port_alloc_alg = NAT_ADDR_AND_PORT_ALLOC_ALG_DEFAULT;
-  sm->forwarding_enabled = 0;
+  sm->fq_in2out_index = ~0;
+  sm->fq_in2out_output_index = ~0;
+
+  sm->log_level = SNAT_LOG_ERROR;
+
+  nat44_set_node_indexes (sm, vm);
   sm->log_class = vlib_log_register_class ("nat", 0);
-  error_drop_node = vlib_get_node_by_name (vm, (u8 *) "error-drop");
-  sm->error_node_index = error_drop_node->index;
-  sm->mss_clamping = 0;
+  nat_ipfix_logging_init (vm);
+
+  nat_init_simple_counter (sm->total_users, "total-users",
+                          "/nat44/total-users");
+  nat_init_simple_counter (sm->total_sessions, "total-sessions",
+                          "/nat44/total-sessions");
+  nat_init_simple_counter (sm->user_limit_reached, "user-limit-reached",
+                          "/nat44/user-limit-reached");
+
+#define _(x)                                            \
+  sm->counters.fastpath.in2out.x.name = #x;             \
+  sm->counters.fastpath.in2out.x.stat_segment_name =    \
+      "/nat44/in2out/fastpath/" #x;                     \
+  sm->counters.slowpath.in2out.x.name = #x;             \
+  sm->counters.slowpath.in2out.x.stat_segment_name =    \
+      "/nat44/in2out/slowpath/" #x;                     \
+  sm->counters.fastpath.out2in.x.name = #x;             \
+  sm->counters.fastpath.out2in.x.stat_segment_name =    \
+      "/nat44/out2in/fastpath/" #x;                     \
+  sm->counters.slowpath.out2in.x.name = #x;             \
+  sm->counters.slowpath.out2in.x.stat_segment_name =    \
+      "/nat44/out2in/slowpath/" #x;                     \
+  sm->counters.fastpath.in2out_ed.x.name = #x;          \
+  sm->counters.fastpath.in2out_ed.x.stat_segment_name = \
+      "/nat44/ed/in2out/fastpath/" #x;                  \
+  sm->counters.slowpath.in2out_ed.x.name = #x;          \
+  sm->counters.slowpath.in2out_ed.x.stat_segment_name = \
+      "/nat44/ed/in2out/slowpath/" #x;                  \
+  sm->counters.fastpath.out2in_ed.x.name = #x;          \
+  sm->counters.fastpath.out2in_ed.x.stat_segment_name = \
+      "/nat44/ed/out2in/fastpath/" #x;                  \
+  sm->counters.slowpath.out2in_ed.x.name = #x;          \
+  sm->counters.slowpath.out2in_ed.x.stat_segment_name = \
+      "/nat44/ed/out2in/slowpath/" #x;
+  foreach_nat_counter;
+#undef _
+  sm->counters.hairpinning.name = "hairpinning";
+  sm->counters.hairpinning.stat_segment_name = "/nat44/hairpinning";
 
   p = hash_get_mem (tm->thread_registrations_by_name, "workers");
   if (p)
@@ -2184,79 +2794,330 @@ snat_init (vlib_main_t * vm)
          sm->first_worker_index = tr->first_index;
        }
     }
-
-  vec_validate (sm->per_thread_data, tm->n_vlib_mains - 1);
+  num_threads = tm->n_vlib_mains - 1;
+  sm->port_per_thread = 0xffff - 1024;
+  vec_validate (sm->per_thread_data, num_threads);
 
   /* Use all available workers by default */
   if (sm->num_workers > 1)
     {
+
       for (i = 0; i < sm->num_workers; i++)
        bitmap = clib_bitmap_set (bitmap, i, 1);
       snat_set_workers (bitmap);
       clib_bitmap_free (bitmap);
     }
   else
+    sm->per_thread_data[0].snat_thread_index = 0;
+
+  /* callbacks to call when interface address changes. */
+  cbi.function = snat_ip4_add_del_interface_address_cb;
+  vec_add1 (sm->ip4_main->add_del_interface_address_callbacks, cbi);
+  cbi.function = nat_ip4_add_del_addr_only_sm_cb;
+  vec_add1 (sm->ip4_main->add_del_interface_address_callbacks, cbi);
+
+  /* callbacks to call when interface to table biding changes */
+  cbt.function = snat_update_outside_fib;
+  vec_add1 (sm->ip4_main->table_bind_callbacks, cbt);
+
+  sm->fib_src_low =
+    fib_source_allocate ("nat-low", FIB_SOURCE_PRIORITY_LOW,
+                        FIB_SOURCE_BH_SIMPLE);
+  sm->fib_src_hi =
+    fib_source_allocate ("nat-hi", FIB_SOURCE_PRIORITY_HI,
+                        FIB_SOURCE_BH_SIMPLE);
+
+  /* used only by out2in-dpo feature */
+  nat_dpo_module_init ();
+
+  nat_affinity_init (vm);
+  nat_ha_init (vm, sm->num_workers, num_threads);
+
+  test_key_calc_split ();
+  return nat44_api_hookup (vm);
+}
+
+VLIB_INIT_FUNCTION (nat_init);
+
+int
+nat44_plugin_enable (nat44_config_t c)
+{
+  snat_main_t *sm = &snat_main;
+  u32 static_mapping_buckets = 1024;
+  u32 static_mapping_memory_size = 64 << 20;
+
+  if (sm->enabled)
     {
-      sm->per_thread_data[0].snat_thread_index = 0;
+      nat_log_err ("nat44 is enabled");
+      return 1;
     }
 
-  error = snat_api_init (vm, sm);
-  if (error)
-    return error;
+  // c.static_mapping_only + c.connection_tracking
+  //  - supported in NAT EI & NAT ED
+  // c.out2in_dpo, c.static_mapping_only
+  //  - supported in NAT EI
 
-  /* Set up the interface address add/del callback */
-  cb4.function = snat_ip4_add_del_interface_address_cb;
-  cb4.function_opaque = 0;
+  if (c.endpoint_dependent)
+    {
+      if ((c.static_mapping_only && !c.connection_tracking) || c.out2in_dpo)
+       {
+         nat_log_err ("unsupported combination of configuration");
+         return 1;
+       }
+      if (c.users || c.user_sessions)
+       {
+         nat_log_err ("unsupported combination of configuration");
+         return 1;
+       }
+    }
 
-  vec_add1 (im->add_del_interface_address_callbacks, cb4);
+  // reset to defaults:
+  sm->alloc_addr_and_port = nat_alloc_addr_and_port_default;
+  sm->addr_and_port_alloc_alg = NAT_ADDR_AND_PORT_ALLOC_ALG_DEFAULT;
+  //
+  sm->udp_timeout = SNAT_UDP_TIMEOUT;
+  sm->icmp_timeout = SNAT_ICMP_TIMEOUT;
+  sm->tcp_transitory_timeout = SNAT_TCP_TRANSITORY_TIMEOUT;
+  sm->tcp_established_timeout = SNAT_TCP_ESTABLISHED_TIMEOUT;
 
-  cb4.function = nat_ip4_add_del_addr_only_sm_cb;
-  cb4.function_opaque = 0;
+  // nat44 feature configuration
+  sm->endpoint_dependent = c.endpoint_dependent;
+  sm->static_mapping_only = c.static_mapping_only;
+  sm->static_mapping_connection_tracking = c.connection_tracking;
+  sm->forwarding_enabled = 0;
+  sm->mss_clamping = 0;
 
-  vec_add1 (im->add_del_interface_address_callbacks, cb4);
+  if (!c.users)
+    c.users = 1024;
 
-  nat_dpo_module_init ();
+  sm->max_users_per_thread = c.users;
+  sm->user_buckets = nat_calc_bihash_buckets (c.users);
+
+  if (!c.sessions)
+    c.sessions = 10 * 1024;
+
+  sm->max_translations_per_thread = c.sessions;
+  sm->translation_buckets = nat_calc_bihash_buckets (c.sessions);
+
+  vec_add1 (sm->max_translations_per_fib, sm->max_translations_per_thread);
+  sm->max_translations_per_user
+    = c.user_sessions ? c.user_sessions : sm->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);
+
+  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);
+
+  if (c.endpoint_dependent)
+    {
+      sm->worker_out2in_cb = nat44_ed_get_worker_out2in_cb;
+      sm->worker_in2out_cb = nat44_ed_get_worker_in2out_cb;
+      sm->out2in_node_index = sm->ed_out2in_node_index;
+      sm->in2out_node_index = sm->ed_in2out_node_index;
+      sm->in2out_output_node_index = sm->ed_in2out_output_node_index;
+      sm->icmp_match_out2in_cb = icmp_match_out2in_ed;
+      sm->icmp_match_in2out_cb = icmp_match_in2out_ed;
+
+      // try to move it into nat44_db_init,
+      // consider static mapping requirements
+      clib_bihash_init_16_8 (&sm->out2in_ed, "out2in-ed",
+                            sm->translation_buckets, 0);
+      clib_bihash_set_kvp_format_fn_16_8 (&sm->out2in_ed,
+                                         format_ed_session_kvp);
+
+
+      nat_affinity_enable ();
+
+      nat_ha_enable (nat_ha_sadd_ed_cb, nat_ha_sdel_ed_cb, nat_ha_sref_ed_cb);
+    }
+  else
+    {
+      sm->worker_out2in_cb = snat_get_worker_out2in_cb;
+      sm->worker_in2out_cb = snat_get_worker_in2out_cb;
+      sm->out2in_node_index = sm->ei_out2in_node_index;
+      sm->in2out_node_index = sm->ei_in2out_node_index;
+      sm->in2out_output_node_index = sm->ei_in2out_output_node_index;
+      sm->icmp_match_out2in_cb = icmp_match_out2in_slow;
+      sm->icmp_match_in2out_cb = icmp_match_in2out_slow;
+
+      nat_ha_enable (nat_ha_sadd_cb, nat_ha_sdel_cb, nat_ha_sref_cb);
+    }
+
+  // c.static_mapping & c.connection_tracking require
+  // session database
+  if (!c.static_mapping_only
+      || (c.static_mapping_only && c.connection_tracking))
+    {
+      snat_main_per_thread_data_t *tsm;
+      /* *INDENT-OFF* */
+      vec_foreach (tsm, sm->per_thread_data)
+        {
+          nat44_db_init (tsm);
+        }
+      /* *INDENT-ON* */
+    }
+  else
+    {
+      sm->icmp_match_in2out_cb = icmp_match_in2out_fast;
+      sm->icmp_match_out2in_cb = icmp_match_out2in_fast;
+    }
 
-  /* Init counters */
-  sm->total_users.name = "total-users";
-  sm->total_users.stat_segment_name = "/nat44/total-users";
-  vlib_validate_simple_counter (&sm->total_users, 0);
+  clib_bihash_init_8_8 (&sm->static_mapping_by_local,
+                       "static_mapping_by_local", 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_init_8_8 (&sm->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_external,
+                                    format_static_mapping_kvp);
+
+  // last: reset counters
   vlib_zero_simple_counter (&sm->total_users, 0);
-  sm->total_sessions.name = "total-sessions";
-  sm->total_sessions.stat_segment_name = "/nat44/total-sessions";
-  vlib_validate_simple_counter (&sm->total_sessions, 0);
   vlib_zero_simple_counter (&sm->total_sessions, 0);
+  vlib_zero_simple_counter (&sm->user_limit_reached, 0);
 
-  /* Init IPFIX logging */
-  snat_ipfix_logging_init (vm);
+  sm->enabled = 1;
+  sm->rconfig = c;
 
-  /* Init NAT64 */
-  error = nat64_init (vm);
-  if (error)
-    return error;
+  return 0;
+}
 
-  dslite_init (vm);
+void
+nat44_addresses_free (snat_address_t ** addresses)
+{
+  snat_address_t *ap;
+  /* *INDENT-OFF* */
+  vec_foreach (ap, *addresses)
+    {
+    #define _(N, i, n, s) \
+      vec_free (ap->busy_##n##_ports_per_thread);
+      foreach_nat_protocol
+    #undef _
+    }
+  /* *INDENT-ON* */
+  vec_free (*addresses);
+  *addresses = 0;
+}
+
+int
+nat44_plugin_disable ()
+{
+  snat_main_t *sm = &snat_main;
+  snat_interface_t *i, *vec;
+  int error = 0;
 
-  nat66_init ();
+  if (!sm->enabled)
+    {
+      nat_log_err ("nat44 is disabled");
+      return 1;
+    }
 
-  /* Init virtual fragmenentation reassembly */
-  return nat_reass_init (vm);
-}
+  // first unregister all nodes from interfaces
+  vec = vec_dup (sm->interfaces);
+  /* *INDENT-OFF* */
+  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 (error)
+        {
+          nat_log_err ("error occurred while removing interface %u",
+                       i->sw_if_index);
+        }
+    }
+  /* *INDENT-ON* */
+  vec_free (vec);
+  sm->interfaces = 0;
+
+  vec = vec_dup (sm->output_feature_interfaces);
+  /* *INDENT-OFF* */
+  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 (error)
+        {
+          nat_log_err ("error occurred while removing interface %u",
+                       i->sw_if_index);
+        }
+    }
+  /* *INDENT-ON* */
+  vec_free (vec);
+  sm->output_feature_interfaces = 0;
+
+  vec_free (sm->max_translations_per_fib);
+
+  if (sm->endpoint_dependent)
+    {
+      nat_affinity_disable ();
+      clib_bihash_free_16_8 (&sm->out2in_ed);
+    }
+
+  clib_bihash_free_8_8 (&sm->static_mapping_by_local);
+  clib_bihash_free_8_8 (&sm->static_mapping_by_external);
+
+  if (!sm->static_mapping_only ||
+      (sm->static_mapping_only && sm->static_mapping_connection_tracking))
+    {
+      snat_main_per_thread_data_t *tsm;
+     /* *INDENT-OFF* */
+      vec_foreach (tsm, sm->per_thread_data)
+        {
+          nat44_db_free (tsm);
+        }
+      /* *INDENT-ON* */
+    }
+
+  pool_free (sm->static_mappings);
+
+  nat44_addresses_free (&sm->addresses);
+  nat44_addresses_free (&sm->twice_nat_addresses);
+
+
+  vec_free (sm->to_resolve);
+  vec_free (sm->auto_add_sw_if_indices);
+  vec_free (sm->auto_add_sw_if_indices_twice_nat);
 
-VLIB_INIT_FUNCTION (snat_init);
+  sm->to_resolve = 0;
+  sm->auto_add_sw_if_indices = 0;
+  sm->auto_add_sw_if_indices_twice_nat = 0;
+
+  sm->forwarding_enabled = 0;
+
+  sm->enabled = 0;
+  clib_memset (&sm->rconfig, 0, sizeof (sm->rconfig));
+
+  return 0;
+}
 
 void
 snat_free_outside_address_and_port (snat_address_t * addresses,
-                                   u32 thread_index, snat_session_key_t * k)
+                                   u32 thread_index,
+                                   ip4_address_t * addr,
+                                   u16 port, nat_protocol_t protocol)
 {
   snat_address_t *a;
   u32 address_index;
-  u16 port_host_byte_order = clib_net_to_host_u16 (k->port);
+  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 == k->addr.as_u32)
+      if (addresses[address_index].addr.as_u32 == addr->as_u32)
        break;
     }
 
@@ -2264,64 +3125,106 @@ snat_free_outside_address_and_port (snat_address_t * addresses,
 
   a = addresses + address_index;
 
-  switch (k->protocol)
+  switch (protocol)
     {
 #define _(N, i, n, s) \
-    case SNAT_PROTOCOL_##N: \
-      ASSERT (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, \
-        port_host_byte_order) == 1); \
-      clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, \
-        port_host_byte_order, 0); \
+    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_snat_protocol
+      foreach_nat_protocol
 #undef _
     default:
-      nat_log_info ("unknown protocol");
+      nat_elog_info ("unknown protocol");
       return;
     }
 }
 
+static int
+nat_set_outside_address_and_port (snat_address_t * addresses,
+                                 u32 thread_index, ip4_address_t addr,
+                                 u16 port, nat_protocol_t protocol)
+{
+  snat_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 ("unknown protocol");
+         return 1;
+       }
+    }
+
+  return VNET_API_ERROR_NO_SUCH_ENTRY;
+}
+
 int
 snat_static_mapping_match (snat_main_t * sm,
-                          snat_session_key_t match,
-                          snat_session_key_t * mapping,
+                          ip4_address_t match_addr,
+                          u16 match_port,
+                          u32 match_fib_index,
+                          nat_protocol_t match_protocol,
+                          ip4_address_t * mapping_addr,
+                          u16 * mapping_port,
+                          u32 * mapping_fib_index,
                           u8 by_external,
                           u8 * is_addr_only,
                           twice_nat_type_t * twice_nat,
                           lb_nat_type_t * lb, ip4_address_t * ext_host_addr,
-                          u8 * is_identity_nat)
+                          u8 * is_identity_nat, snat_static_mapping_t ** out)
 {
   clib_bihash_kv_8_8_t kv, value;
+  clib_bihash_8_8_t *mapping_hash;
   snat_static_mapping_t *m;
-  snat_session_key_t m_key;
-  clib_bihash_8_8_t *mapping_hash = &sm->static_mapping_by_local;
   u32 rand, lo = 0, hi, mid, *tmp = 0, i;
-  u8 backend_index;
   nat44_lb_addr_port_t *local;
+  u8 backend_index;
 
-  m_key.fib_index = match.fib_index;
-  if (by_external)
+  if (!by_external)
     {
-      mapping_hash = &sm->static_mapping_by_external;
-      m_key.fib_index = 0;
+      mapping_hash = &sm->static_mapping_by_local;
+      init_nat_k (&kv, match_addr, match_port, match_fib_index,
+                 match_protocol);
+      if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
+       {
+         /* Try address only mapping */
+         init_nat_k (&kv, match_addr, 0, match_fib_index, 0);
+         if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
+           return 1;
+       }
     }
-
-  m_key.addr = match.addr;
-  m_key.port = clib_net_to_host_u16 (match.port);
-  m_key.protocol = match.protocol;
-
-  kv.key = m_key.as_u64;
-
-  if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
+  else
     {
-      /* Try address only mapping */
-      m_key.port = 0;
-      m_key.protocol = 0;
-      kv.key = m_key.as_u64;
+      mapping_hash = &sm->static_mapping_by_external;
+      init_nat_k (&kv, match_addr, match_port, 0, match_protocol);
       if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
-       return 1;
+       {
+         /* Try address only mapping */
+         init_nat_k (&kv, match_addr, 0, 0, 0);
+         if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
+           return 1;
+       }
     }
 
   m = pool_elt_at_index (sm->static_mappings, value.value);
@@ -2332,26 +3235,49 @@ snat_static_mapping_match (snat_main_t * sm,
        {
          if (PREDICT_FALSE (lb != 0))
            *lb = m->affinity ? AFFINITY_LB_NAT : LB_NAT;
-         if (m->affinity)
+         if (m->affinity && !nat_affinity_find_and_lock (ext_host_addr[0],
+                                                         match_addr,
+                                                         match_protocol,
+                                                         match_port,
+                                                         &backend_index))
            {
-             if (nat_affinity_find_and_lock (ext_host_addr[0], match.addr,
-                                             match.protocol, match.port,
-                                             &backend_index))
-               goto get_local;
-
              local = pool_elt_at_index (m->locals, backend_index);
-             mapping->addr = local->addr;
-             mapping->port = clib_host_to_net_u16 (local->port);
-             mapping->fib_index = local->fib_index;
+             *mapping_addr = local->addr;
+             *mapping_port = local->port;
+             *mapping_fib_index = local->fib_index;
              goto end;
            }
-       get_local:
-          /* *INDENT-OFF* */
-          pool_foreach_index (i, m->locals,
-          ({
-            vec_add1 (tmp, i);
-          }));
-          /* *INDENT-ON* */
+         // pick locals matching this worker
+         if (PREDICT_FALSE (sm->num_workers > 1))
+           {
+             u32 thread_index = vlib_get_thread_index ();
+              /* *INDENT-OFF* */
+              pool_foreach_index (i, m->locals,
+              ({
+                local = pool_elt_at_index (m->locals, i);
+
+                ip4_header_t ip = {
+                 .src_address = local->addr,
+               };
+
+               if (sm->worker_in2out_cb (&ip, m->fib_index, 0) ==
+                   thread_index)
+                  {
+                    vec_add1 (tmp, i);
+                  }
+              }));
+              /* *INDENT-ON* */
+             ASSERT (vec_len (tmp) != 0);
+           }
+         else
+           {
+              /* *INDENT-OFF* */
+              pool_foreach_index (i, m->locals,
+              ({
+                vec_add1 (tmp, i);
+              }));
+              /* *INDENT-ON* */
+           }
          hi = vec_len (tmp) - 1;
          local = pool_elt_at_index (m->locals, tmp[hi]);
          rand = 1 + (random_u32 (&sm->random_seed) % local->prefix);
@@ -2364,25 +3290,16 @@ snat_static_mapping_match (snat_main_t * sm,
          local = pool_elt_at_index (m->locals, tmp[lo]);
          if (!(local->prefix >= rand))
            return 1;
-         if (PREDICT_FALSE (sm->num_workers > 1))
-           {
-             ip4_header_t ip = {
-               .src_address = local->addr,
-             };
-             if (sm->worker_in2out_cb (&ip, m->fib_index) !=
-                 vlib_get_thread_index ())
-               goto get_local;
-           }
-         mapping->addr = local->addr;
-         mapping->port = clib_host_to_net_u16 (local->port);
-         mapping->fib_index = local->fib_index;
+         *mapping_addr = local->addr;
+         *mapping_port = local->port;
+         *mapping_fib_index = local->fib_index;
          if (m->affinity)
            {
-             if (nat_affinity_create_and_lock (ext_host_addr[0], match.addr,
-                                               match.protocol, match.port,
+             if (nat_affinity_create_and_lock (ext_host_addr[0], match_addr,
+                                               match_protocol, match_port,
                                                tmp[lo], m->affinity,
                                                m->affinity_per_service_list_head_index))
-               nat_log_info ("create affinity record failed");
+               nat_elog_info ("create affinity record failed");
            }
          vec_free (tmp);
        }
@@ -2390,21 +3307,20 @@ snat_static_mapping_match (snat_main_t * sm,
        {
          if (PREDICT_FALSE (lb != 0))
            *lb = NO_LB_NAT;
-         mapping->fib_index = m->fib_index;
-         mapping->addr = m->local_addr;
+         *mapping_fib_index = m->fib_index;
+         *mapping_addr = m->local_addr;
          /* Address only mapping doesn't change port */
-         mapping->port = is_addr_only_static_mapping (m) ? match.port
-           : clib_host_to_net_u16 (m->local_port);
+         *mapping_port = is_addr_only_static_mapping (m) ? match_port
+           : m->local_port;
        }
-      mapping->protocol = m->proto;
     }
   else
     {
-      mapping->addr = m->external_addr;
+      *mapping_addr = m->external_addr;
       /* Address only mapping doesn't change port */
-      mapping->port = is_addr_only_static_mapping (m) ? match.port
-       : clib_host_to_net_u16 (m->external_port);
-      mapping->fib_index = sm->outside_fib_index;
+      *mapping_port = is_addr_only_static_mapping (m) ? match_port
+       : m->external_port;
+      *mapping_fib_index = sm->outside_fib_index;
     }
 
 end:
@@ -2417,36 +3333,36 @@ end:
   if (PREDICT_FALSE (is_identity_nat != 0))
     *is_identity_nat = is_identity_static_mapping (m);
 
-  return 0;
-}
+  if (out != 0)
+    *out = m;
 
-static_always_inline u16
-snat_random_port (u16 min, u16 max)
-{
-  snat_main_t *sm = &snat_main;
-  return min + random_u32 (&sm->random_seed) /
-    (random_u32_max () / (max - min + 1) + 1);
+  return 0;
 }
 
 int
 snat_alloc_outside_address_and_port (snat_address_t * addresses,
                                     u32 fib_index,
                                     u32 thread_index,
-                                    snat_session_key_t * k,
+                                    nat_protocol_t proto,
+                                    ip4_address_t * addr,
+                                    u16 * port,
                                     u16 port_per_thread,
                                     u32 snat_thread_index)
 {
   snat_main_t *sm = &snat_main;
 
-  return sm->alloc_addr_and_port (addresses, fib_index, thread_index, k,
-                                 port_per_thread, snat_thread_index);
+  return sm->alloc_addr_and_port (addresses, fib_index, thread_index, proto,
+                                 addr, port, port_per_thread,
+                                 snat_thread_index);
 }
 
 static int
 nat_alloc_addr_and_port_default (snat_address_t * addresses,
                                 u32 fib_index,
                                 u32 thread_index,
-                                snat_session_key_t * k,
+                                nat_protocol_t proto,
+                                ip4_address_t * addr,
+                                u16 * port,
                                 u16 port_per_thread, u32 snat_thread_index)
 {
   int i;
@@ -2456,10 +3372,10 @@ nat_alloc_addr_and_port_default (snat_address_t * addresses,
   for (i = 0; i < vec_len (addresses); i++)
     {
       a = addresses + i;
-      switch (k->protocol)
+      switch (proto)
        {
 #define _(N, j, n, s) \
-        case SNAT_PROTOCOL_##N: \
+        case NAT_PROTOCOL_##N: \
           if (a->busy_##n##_ports_per_thread[thread_index] < port_per_thread) \
             { \
               if (a->fib_index == fib_index) \
@@ -2468,14 +3384,14 @@ nat_alloc_addr_and_port_default (snat_address_t * addresses,
                     { \
                       portnum = (port_per_thread * \
                         snat_thread_index) + \
-                        snat_random_port(1, port_per_thread) + 1024; \
-                      if (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, portnum)) \
+                        snat_random_port(0, port_per_thread - 1) + 1024; \
+                      if (a->busy_##n##_port_refcounts[portnum]) \
                         continue; \
-                      clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, portnum, 1); \
+                     --a->busy_##n##_port_refcounts[portnum]; \
                       a->busy_##n##_ports_per_thread[thread_index]++; \
                       a->busy_##n##_ports++; \
-                      k->addr = a->addr; \
-                      k->port = clib_host_to_net_u16(portnum); \
+                      *addr = a->addr; \
+                      *port = clib_host_to_net_u16(portnum); \
                       return 0; \
                     } \
                 } \
@@ -2485,10 +3401,10 @@ nat_alloc_addr_and_port_default (snat_address_t * addresses,
                 } \
             } \
           break;
-         foreach_snat_protocol
+         foreach_nat_protocol
 #undef _
        default:
-         nat_log_info ("unknown protocol");
+         nat_elog_info ("unknown protocol");
          return 1;
        }
 
@@ -2497,43 +3413,42 @@ nat_alloc_addr_and_port_default (snat_address_t * addresses,
   if (ga)
     {
       a = ga;
-      switch (k->protocol)
+      switch (proto)
        {
 #define _(N, j, n, s) \
-        case SNAT_PROTOCOL_##N: \
+        case NAT_PROTOCOL_##N: \
           while (1) \
             { \
               portnum = (port_per_thread * \
                 snat_thread_index) + \
-                snat_random_port(1, port_per_thread) + 1024; \
-              if (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, portnum)) \
+                snat_random_port(0, port_per_thread - 1) + 1024; \
+             if (a->busy_##n##_port_refcounts[portnum]) \
                 continue; \
-              clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, portnum, 1); \
+             ++a->busy_##n##_port_refcounts[portnum]; \
               a->busy_##n##_ports_per_thread[thread_index]++; \
               a->busy_##n##_ports++; \
-              k->addr = a->addr; \
-              k->port = clib_host_to_net_u16(portnum); \
+              *addr = a->addr; \
+              *port = clib_host_to_net_u16(portnum); \
               return 0; \
             }
          break;
-         foreach_snat_protocol
+         foreach_nat_protocol
 #undef _
        default:
-         nat_log_info ("unknown protocol");
+         nat_elog_info ("unknown protocol");
          return 1;
        }
     }
 
   /* Totally out of translations to use... */
-  snat_ipfix_logging_addresses_exhausted (0);
+  nat_ipfix_logging_addresses_exhausted (thread_index, 0);
   return 1;
 }
 
 static int
-nat_alloc_addr_and_port_mape (snat_address_t * addresses,
-                             u32 fib_index,
-                             u32 thread_index,
-                             snat_session_key_t * k,
+nat_alloc_addr_and_port_mape (snat_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;
@@ -2545,10 +3460,10 @@ nat_alloc_addr_and_port_mape (snat_address_t * addresses,
   if (!vec_len (addresses))
     goto exhausted;
 
-  switch (k->protocol)
+  switch (proto)
     {
 #define _(N, i, n, s) \
-    case SNAT_PROTOCOL_##N: \
+    case NAT_PROTOCOL_##N: \
       if (a->busy_##n##_ports < ports) \
         { \
           while (1) \
@@ -2556,34 +3471,33 @@ nat_alloc_addr_and_port_mape (snat_address_t * addresses,
               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)); \
-              if (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, portnum)) \
+             if (a->busy_##n##_port_refcounts[portnum]) \
                 continue; \
-              clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, portnum, 1); \
+             ++a->busy_##n##_port_refcounts[portnum]; \
               a->busy_##n##_ports++; \
-              k->addr = a->addr; \
-              k->port = clib_host_to_net_u16 (portnum); \
+              *addr = a->addr; \
+              *port = clib_host_to_net_u16 (portnum); \
               return 0; \
             } \
         } \
       break;
-      foreach_snat_protocol
+      foreach_nat_protocol
 #undef _
     default:
-      nat_log_info ("unknown protocol");
+      nat_elog_info ("unknown protocol");
       return 1;
     }
 
 exhausted:
   /* Totally out of translations to use... */
-  snat_ipfix_logging_addresses_exhausted (0);
+  nat_ipfix_logging_addresses_exhausted (thread_index, 0);
   return 1;
 }
 
 static int
-nat_alloc_addr_and_port_range (snat_address_t * addresses,
-                              u32 fib_index,
-                              u32 thread_index,
-                              snat_session_key_t * k,
+nat_alloc_addr_and_port_range (snat_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;
@@ -2595,41 +3509,42 @@ nat_alloc_addr_and_port_range (snat_address_t * addresses,
   if (!vec_len (addresses))
     goto exhausted;
 
-  switch (k->protocol)
+  switch (proto)
     {
 #define _(N, i, n, s) \
-    case SNAT_PROTOCOL_##N: \
+    case NAT_PROTOCOL_##N: \
       if (a->busy_##n##_ports < ports) \
         { \
           while (1) \
             { \
               portnum = snat_random_port(sm->start_port, sm->end_port); \
-              if (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, portnum)) \
+             if (a->busy_##n##_port_refcounts[portnum]) \
                 continue; \
-              clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, portnum, 1); \
+             ++a->busy_##n##_port_refcounts[portnum]; \
               a->busy_##n##_ports++; \
-              k->addr = a->addr; \
-              k->port = clib_host_to_net_u16 (portnum); \
+              *addr = a->addr; \
+              *port = clib_host_to_net_u16 (portnum); \
               return 0; \
             } \
         } \
       break;
-      foreach_snat_protocol
+      foreach_nat_protocol
 #undef _
     default:
-      nat_log_info ("unknown protocol");
+      nat_elog_info ("unknown protocol");
       return 1;
     }
 
 exhausted:
   /* Totally out of translations to use... */
-  snat_ipfix_logging_addresses_exhausted (0);
+  nat_ipfix_logging_addresses_exhausted (thread_index, 0);
   return 1;
 }
 
 void
 nat44_add_del_address_dpo (ip4_address_t addr, u8 is_add)
 {
+  snat_main_t *sm = &snat_main;
   dpo_id_t dpo_v4 = DPO_INVALID;
   fib_prefix_t pfx = {
     .fp_proto = FIB_PROTOCOL_IP4,
@@ -2640,77 +3555,19 @@ nat44_add_del_address_dpo (ip4_address_t addr, u8 is_add)
   if (is_add)
     {
       nat_dpo_create (DPO_PROTO_IP4, 0, &dpo_v4);
-      fib_table_entry_special_dpo_add (0, &pfx, FIB_SOURCE_PLUGIN_HI,
+      fib_table_entry_special_dpo_add (0, &pfx, sm->fib_src_hi,
                                       FIB_ENTRY_FLAG_EXCLUSIVE, &dpo_v4);
       dpo_reset (&dpo_v4);
     }
   else
     {
-      fib_table_entry_special_remove (0, &pfx, FIB_SOURCE_PLUGIN_HI);
+      fib_table_entry_special_remove (0, &pfx, sm->fib_src_hi);
     }
 }
 
-u8 *
-format_session_kvp (u8 * s, va_list * args)
-{
-  clib_bihash_kv_8_8_t *v = va_arg (*args, clib_bihash_kv_8_8_t *);
-  snat_session_key_t k;
-
-  k.as_u64 = v->key;
-
-  s = format (s, "%U session-index %llu", format_snat_key, &k, v->value);
-
-  return s;
-}
-
-u8 *
-format_static_mapping_kvp (u8 * s, va_list * args)
-{
-  clib_bihash_kv_8_8_t *v = va_arg (*args, clib_bihash_kv_8_8_t *);
-  snat_session_key_t k;
-
-  k.as_u64 = v->key;
-
-  s = format (s, "%U static-mapping-index %llu",
-             format_static_mapping_key, &k, v->value);
-
-  return s;
-}
-
-u8 *
-format_user_kvp (u8 * s, va_list * args)
-{
-  clib_bihash_kv_8_8_t *v = va_arg (*args, clib_bihash_kv_8_8_t *);
-  snat_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_ed_session_kvp (u8 * s, va_list * args)
-{
-  clib_bihash_kv_16_8_t *v = va_arg (*args, clib_bihash_kv_16_8_t *);
-  nat_ed_ses_key_t k;
-
-  k.as_u64[0] = v->key[0];
-  k.as_u64[1] = v->key[1];
-
-  s =
-    format (s, "local %U:%d remote %U:%d proto %U fib %d session-index %llu",
-           format_ip4_address, &k.l_addr, clib_net_to_host_u16 (k.l_port),
-           format_ip4_address, &k.r_addr, clib_net_to_host_u16 (k.r_port),
-           format_ip_protocol, k.proto, k.fib_index, v->value);
-
-  return s;
-}
-
 static u32
-snat_get_worker_in2out_cb (ip4_header_t * ip0, u32 rx_fib_index0)
+snat_get_worker_in2out_cb (ip4_header_t * ip0, u32 rx_fib_index0,
+                          u8 is_output)
 {
   snat_main_t *sm = &snat_main;
   u32 next_worker_index = 0;
@@ -2729,12 +3586,12 @@ snat_get_worker_in2out_cb (ip4_header_t * ip0, u32 rx_fib_index0)
 }
 
 static u32
-snat_get_worker_out2in_cb (ip4_header_t * ip0, u32 rx_fib_index0)
+snat_get_worker_out2in_cb (vlib_buffer_t * b, ip4_header_t * ip0,
+                          u32 rx_fib_index0, u8 is_output)
 {
   snat_main_t *sm = &snat_main;
   udp_header_t *udp;
   u16 port;
-  snat_session_key_t m_key;
   clib_bihash_kv_8_8_t kv, value;
   snat_static_mapping_t *m;
   u32 proto;
@@ -2743,11 +3600,7 @@ snat_get_worker_out2in_cb (ip4_header_t * ip0, u32 rx_fib_index0)
   /* first try static mappings without port */
   if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
     {
-      m_key.addr = ip0->dst_address;
-      m_key.port = 0;
-      m_key.protocol = 0;
-      m_key.fib_index = rx_fib_index0;
-      kv.key = m_key.as_u64;
+      init_nat_k (&kv, ip0->dst_address, 0, rx_fib_index0, 0);
       if (!clib_bihash_search_8_8
          (&sm->static_mapping_by_external, &kv, &value))
        {
@@ -2756,31 +3609,12 @@ snat_get_worker_out2in_cb (ip4_header_t * ip0, u32 rx_fib_index0)
        }
     }
 
-  proto = ip_proto_to_snat_proto (ip0->protocol);
+  proto = ip_proto_to_nat_proto (ip0->protocol);
   udp = ip4_next_header (ip0);
   port = udp->dst_port;
 
-  if (PREDICT_FALSE (ip4_is_fragment (ip0)))
-    {
-      if (PREDICT_FALSE (nat_reass_is_drop_frag (0)))
-       return vlib_get_thread_index ();
-
-      if (PREDICT_TRUE (!ip4_is_first_fragment (ip0)))
-       {
-         nat_reass_ip4_t *reass;
-
-         reass = nat_ip4_reass_find (ip0->src_address, ip0->dst_address,
-                                     ip0->fragment_id, ip0->protocol);
-
-         if (reass && (reass->thread_index != (u32) ~ 0))
-           return reass->thread_index;
-         else
-           return vlib_get_thread_index ();
-       }
-    }
-
   /* unknown protocol */
-  if (PREDICT_FALSE (proto == ~0))
+  if (PREDICT_FALSE (proto == NAT_PROTOCOL_OTHER))
     {
       /* use current thread */
       return vlib_get_thread_index ();
@@ -2790,22 +3624,24 @@ snat_get_worker_out2in_cb (ip4_header_t * ip0, u32 rx_fib_index0)
     {
       icmp46_header_t *icmp = (icmp46_header_t *) udp;
       icmp_echo_header_t *echo = (icmp_echo_header_t *) (icmp + 1);
-      if (!icmp_is_error_message (icmp))
-       port = echo->identifier;
+      if (!icmp_type_is_error_message
+         (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
+       port = vnet_buffer (b)->ip.reass.l4_src_port;
       else
        {
+         /* if error message, then it's not fragmented and we can access it */
          ip4_header_t *inner_ip = (ip4_header_t *) (echo + 1);
-         proto = ip_proto_to_snat_proto (inner_ip->protocol);
+         proto = ip_proto_to_nat_proto (inner_ip->protocol);
          void *l4_header = ip4_next_header (inner_ip);
          switch (proto)
            {
-           case SNAT_PROTOCOL_ICMP:
+           case NAT_PROTOCOL_ICMP:
              icmp = (icmp46_header_t *) l4_header;
              echo = (icmp_echo_header_t *) (icmp + 1);
              port = echo->identifier;
              break;
-           case SNAT_PROTOCOL_UDP:
-           case SNAT_PROTOCOL_TCP:
+           case NAT_PROTOCOL_UDP:
+           case NAT_PROTOCOL_TCP:
              port = ((tcp_udp_header_t *) l4_header)->src_port;
              break;
            default:
@@ -2817,11 +3653,7 @@ snat_get_worker_out2in_cb (ip4_header_t * ip0, u32 rx_fib_index0)
   /* try static mappings with port */
   if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
     {
-      m_key.addr = ip0->dst_address;
-      m_key.port = clib_net_to_host_u16 (port);
-      m_key.protocol = proto;
-      m_key.fib_index = rx_fib_index0;
-      kv.key = m_key.as_u64;
+      init_nat_k (&kv, ip0->dst_address, port, rx_fib_index0, proto);
       if (!clib_bihash_search_8_8
          (&sm->static_mapping_by_external, &kv, &value))
        {
@@ -2838,35 +3670,190 @@ snat_get_worker_out2in_cb (ip4_header_t * ip0, u32 rx_fib_index0)
 }
 
 static u32
-nat44_ed_get_worker_out2in_cb (ip4_header_t * ip, u32 rx_fib_index)
+nat44_ed_get_worker_in2out_cb (ip4_header_t * ip, u32 rx_fib_index,
+                              u8 is_output)
+{
+  snat_main_t *sm = &snat_main;
+  u32 next_worker_index = sm->first_worker_index;
+  u32 hash;
+
+  clib_bihash_kv_16_8_t kv16, value16;
+  snat_main_per_thread_data_t *tsm;
+  udp_header_t *udp;
+
+  if (PREDICT_FALSE (is_output))
+    {
+      u32 fib_index = sm->outside_fib_index;
+      nat_outside_fib_t *outside_fib;
+      fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
+      fib_prefix_t pfx = {
+       .fp_proto = FIB_PROTOCOL_IP4,
+       .fp_len = 32,
+       .fp_addr = {
+                   .ip4.as_u32 = ip->dst_address.as_u32,
+                   }
+       ,
+      };
+
+      udp = ip4_next_header (ip);
+
+      switch (vec_len (sm->outside_fibs))
+       {
+       case 0:
+         fib_index = sm->outside_fib_index;
+         break;
+       case 1:
+         fib_index = sm->outside_fibs[0].fib_index;
+         break;
+       default:
+            /* *INDENT-OFF* */
+            vec_foreach (outside_fib, sm->outside_fibs)
+              {
+                fei = fib_table_lookup (outside_fib->fib_index, &pfx);
+                if (FIB_NODE_INDEX_INVALID != fei)
+                  {
+                    if (fib_entry_get_resolving_interface (fei) != ~0)
+                      {
+                        fib_index = outside_fib->fib_index;
+                        break;
+                      }
+                  }
+              }
+            /* *INDENT-ON* */
+         break;
+       }
+
+      init_ed_k (&kv16, ip->src_address, udp->src_port, ip->dst_address,
+                udp->dst_port, fib_index, ip->protocol);
+
+      if (PREDICT_TRUE (!clib_bihash_search_16_8 (&sm->out2in_ed,
+                                                 &kv16, &value16)))
+       {
+         tsm =
+           vec_elt_at_index (sm->per_thread_data,
+                             ed_value_get_thread_index (&value16));
+         next_worker_index += tsm->thread_index;
+
+         nat_elog_debug_handoff ("HANDOFF IN2OUT-OUTPUT-FEATURE (session)",
+                                 next_worker_index, fib_index,
+                                 clib_net_to_host_u32 (ip->
+                                                       src_address.as_u32),
+                                 clib_net_to_host_u32 (ip->
+                                                       dst_address.as_u32));
+
+         return next_worker_index;
+       }
+    }
+
+  hash = ip->src_address.as_u32 + (ip->src_address.as_u32 >> 8) +
+    (ip->src_address.as_u32 >> 16) + (ip->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)];
+  else
+    next_worker_index += sm->workers[hash % _vec_len (sm->workers)];
+
+  if (PREDICT_TRUE (!is_output))
+    {
+      nat_elog_debug_handoff ("HANDOFF IN2OUT",
+                             next_worker_index, rx_fib_index,
+                             clib_net_to_host_u32 (ip->src_address.as_u32),
+                             clib_net_to_host_u32 (ip->dst_address.as_u32));
+    }
+  else
+    {
+      nat_elog_debug_handoff ("HANDOFF IN2OUT-OUTPUT-FEATURE",
+                             next_worker_index, rx_fib_index,
+                             clib_net_to_host_u32 (ip->src_address.as_u32),
+                             clib_net_to_host_u32 (ip->dst_address.as_u32));
+    }
+
+  return next_worker_index;
+}
+
+static u32
+nat44_ed_get_worker_out2in_cb (vlib_buffer_t * b, ip4_header_t * ip,
+                              u32 rx_fib_index, u8 is_output)
 {
   snat_main_t *sm = &snat_main;
   clib_bihash_kv_8_8_t kv, value;
+  clib_bihash_kv_16_8_t kv16, value16;
+  snat_main_per_thread_data_t *tsm;
+
   u32 proto, next_worker_index = 0;
   udp_header_t *udp;
   u16 port;
   snat_static_mapping_t *m;
   u32 hash;
 
+  proto = ip_proto_to_nat_proto (ip->protocol);
+
+  if (PREDICT_TRUE (proto == NAT_PROTOCOL_UDP || proto == NAT_PROTOCOL_TCP))
+    {
+      udp = ip4_next_header (ip);
+
+      init_ed_k (&kv16, ip->dst_address, udp->dst_port, ip->src_address,
+                udp->src_port, rx_fib_index, ip->protocol);
+
+      if (PREDICT_TRUE (!clib_bihash_search_16_8 (&sm->out2in_ed,
+                                                 &kv16, &value16)))
+       {
+         tsm =
+           vec_elt_at_index (sm->per_thread_data,
+                             ed_value_get_thread_index (&value16));
+         vnet_buffer2 (b)->nat.ed_out2in_nat_session_index =
+           ed_value_get_session_index (&value16);
+         next_worker_index = sm->first_worker_index + tsm->thread_index;
+         nat_elog_debug_handoff ("HANDOFF OUT2IN (session)",
+                                 next_worker_index, rx_fib_index,
+                                 clib_net_to_host_u32 (ip->
+                                                       src_address.as_u32),
+                                 clib_net_to_host_u32 (ip->
+                                                       dst_address.as_u32));
+         return next_worker_index;
+       }
+    }
+  else if (proto == NAT_PROTOCOL_ICMP)
+    {
+      if (!get_icmp_o2i_ed_key (b, ip, rx_fib_index, ~0, ~0, 0, 0, 0, &kv16))
+       {
+         if (PREDICT_TRUE (!clib_bihash_search_16_8 (&sm->out2in_ed,
+                                                     &kv16, &value16)))
+           {
+             tsm =
+               vec_elt_at_index (sm->per_thread_data,
+                                 ed_value_get_thread_index (&value16));
+             next_worker_index = sm->first_worker_index + tsm->thread_index;
+             nat_elog_debug_handoff ("HANDOFF OUT2IN (session)",
+                                     next_worker_index, rx_fib_index,
+                                     clib_net_to_host_u32 (ip->
+                                                           src_address.as_u32),
+                                     clib_net_to_host_u32 (ip->
+                                                           dst_address.as_u32));
+             return next_worker_index;
+           }
+       }
+    }
+
   /* first try static mappings without port */
   if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
     {
-      make_sm_kv (&kv, &ip->dst_address, 0, rx_fib_index, 0);
+      init_nat_k (&kv, ip->dst_address, 0, 0, 0);
       if (!clib_bihash_search_8_8
          (&sm->static_mapping_by_external, &kv, &value))
        {
          m = pool_elt_at_index (sm->static_mappings, value.value);
-         return m->workers[0];
+         next_worker_index = m->workers[0];
+         goto done;
        }
     }
 
-  proto = ip_proto_to_snat_proto (ip->protocol);
-
   /* unknown protocol */
-  if (PREDICT_FALSE (proto == ~0))
+  if (PREDICT_FALSE (proto == NAT_PROTOCOL_OTHER))
     {
       /* use current thread */
-      return vlib_get_thread_index ();
+      next_worker_index = vlib_get_thread_index ();
+      goto done;
     }
 
   udp = ip4_next_header (ip);
@@ -2876,26 +3863,29 @@ nat44_ed_get_worker_out2in_cb (ip4_header_t * ip, u32 rx_fib_index)
     {
       icmp46_header_t *icmp = (icmp46_header_t *) udp;
       icmp_echo_header_t *echo = (icmp_echo_header_t *) (icmp + 1);
-      if (!icmp_is_error_message (icmp))
-       port = echo->identifier;
+      if (!icmp_type_is_error_message
+         (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
+       port = vnet_buffer (b)->ip.reass.l4_src_port;
       else
        {
+         /* if error message, then it's not fragmented and we can access it */
          ip4_header_t *inner_ip = (ip4_header_t *) (echo + 1);
-         proto = ip_proto_to_snat_proto (inner_ip->protocol);
+         proto = ip_proto_to_nat_proto (inner_ip->protocol);
          void *l4_header = ip4_next_header (inner_ip);
          switch (proto)
            {
-           case SNAT_PROTOCOL_ICMP:
+           case NAT_PROTOCOL_ICMP:
              icmp = (icmp46_header_t *) l4_header;
              echo = (icmp_echo_header_t *) (icmp + 1);
              port = echo->identifier;
              break;
-           case SNAT_PROTOCOL_UDP:
-           case SNAT_PROTOCOL_TCP:
+           case NAT_PROTOCOL_UDP:
+           case NAT_PROTOCOL_TCP:
              port = ((tcp_udp_header_t *) l4_header)->src_port;
              break;
            default:
-             return vlib_get_thread_index ();
+             next_worker_index = vlib_get_thread_index ();
+             goto done;
            }
        }
     }
@@ -2903,22 +3893,26 @@ nat44_ed_get_worker_out2in_cb (ip4_header_t * ip, u32 rx_fib_index)
   /* try static mappings with port */
   if (PREDICT_FALSE (pool_elts (sm->static_mappings)))
     {
-      make_sm_kv (&kv, &ip->dst_address, proto, rx_fib_index,
-                 clib_net_to_host_u16 (port));
+      init_nat_k (&kv, ip->dst_address, port, 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 (!is_lb_static_mapping (m))
-           return m->workers[0];
+           {
+             next_worker_index = m->workers[0];
+             goto done;
+           }
 
          hash = ip->src_address.as_u32 + (ip->src_address.as_u32 >> 8) +
            (ip->src_address.as_u32 >> 16) + (ip->src_address.as_u32 >> 24);
 
          if (PREDICT_TRUE (is_pow2 (_vec_len (m->workers))))
-           return m->workers[hash & (_vec_len (m->workers) - 1)];
+           next_worker_index =
+             m->workers[hash & (_vec_len (m->workers) - 1)];
          else
-           return m->workers[hash % _vec_len (m->workers)];
+           next_worker_index = m->workers[hash % _vec_len (m->workers)];
+         goto done;
        }
     }
 
@@ -2927,223 +3921,484 @@ nat44_ed_get_worker_out2in_cb (ip4_header_t * ip, u32 rx_fib_index)
   next_worker_index +=
     sm->workers[(clib_net_to_host_u16 (port) - 1024) / sm->port_per_thread];
 
+done:
+  nat_elog_debug_handoff ("HANDOFF OUT2IN", next_worker_index, rx_fib_index,
+                         clib_net_to_host_u32 (ip->src_address.as_u32),
+                         clib_net_to_host_u32 (ip->dst_address.as_u32));
   return next_worker_index;
 }
 
-static clib_error_t *
-snat_config (vlib_main_t * vm, unformat_input_t * input)
+void
+nat_ha_sadd_cb (ip4_address_t * in_addr, u16 in_port,
+               ip4_address_t * out_addr, u16 out_port,
+               ip4_address_t * eh_addr, u16 eh_port,
+               ip4_address_t * ehn_addr, u16 ehn_port, u8 proto,
+               u32 fib_index, u16 flags, u32 thread_index)
 {
   snat_main_t *sm = &snat_main;
-  nat66_main_t *nm = &nat66_main;
-  u32 translation_buckets = 1024;
-  u32 translation_memory_size = 128 << 20;
-  u32 user_buckets = 128;
-  u32 user_memory_size = 64 << 20;
-  u32 max_translations_per_user = 100;
-  u32 outside_vrf_id = 0;
-  u32 outside_ip6_vrf_id = 0;
-  u32 inside_vrf_id = 0;
-  u32 static_mapping_buckets = 1024;
-  u32 static_mapping_memory_size = 64 << 20;
-  u32 nat64_bib_buckets = 1024;
-  u32 nat64_bib_memory_size = 128 << 20;
-  u32 nat64_st_buckets = 2048;
-  u32 nat64_st_memory_size = 256 << 20;
-  u8 static_mapping_only = 0;
-  u8 static_mapping_connection_tracking = 0;
-  snat_main_per_thread_data_t *tsm;
-  dslite_main_t *dm = &dslite_main;
-
-  sm->deterministic = 0;
-  sm->out2in_dpo = 0;
-  sm->endpoint_dependent = 0;
-
-  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
-    {
-      if (unformat
-         (input, "translation hash buckets %d", &translation_buckets))
-       ;
-      else if (unformat (input, "translation hash memory %d",
-                        &translation_memory_size));
-      else if (unformat (input, "user hash buckets %d", &user_buckets))
-       ;
-      else if (unformat (input, "user hash memory %d", &user_memory_size))
-       ;
-      else if (unformat (input, "max translations per user %d",
-                        &max_translations_per_user))
-       ;
-      else if (unformat (input, "outside VRF id %d", &outside_vrf_id))
-       ;
-      else if (unformat (input, "outside ip6 VRF id %d", &outside_ip6_vrf_id))
-       ;
-      else if (unformat (input, "inside VRF id %d", &inside_vrf_id))
-       ;
-      else if (unformat (input, "static mapping only"))
-       {
-         static_mapping_only = 1;
-         if (unformat (input, "connection tracking"))
-           static_mapping_connection_tracking = 1;
-       }
-      else if (unformat (input, "deterministic"))
-       sm->deterministic = 1;
-      else if (unformat (input, "nat64 bib hash buckets %d",
-                        &nat64_bib_buckets))
-       ;
-      else if (unformat (input, "nat64 bib hash memory %d",
-                        &nat64_bib_memory_size))
-       ;
-      else
-       if (unformat (input, "nat64 st hash buckets %d", &nat64_st_buckets))
-       ;
-      else if (unformat (input, "nat64 st hash memory %d",
-                        &nat64_st_memory_size))
-       ;
-      else if (unformat (input, "out2in dpo"))
-       sm->out2in_dpo = 1;
-      else if (unformat (input, "dslite ce"))
-       dslite_set_ce (dm, 1);
-      else if (unformat (input, "endpoint-dependent"))
-       sm->endpoint_dependent = 1;
-      else
-       return clib_error_return (0, "unknown input '%U'",
-                                 format_unformat_error, input);
-    }
-
-  if (sm->deterministic && sm->endpoint_dependent)
-    return clib_error_return (0,
-                             "deterministic and endpoint-dependent modes are mutually exclusive");
-
-  if (static_mapping_only && (sm->deterministic || sm->endpoint_dependent))
-    return clib_error_return (0,
-                             "static mapping only mode available only for simple nat");
-
-  if (sm->out2in_dpo && (sm->deterministic || sm->endpoint_dependent))
-    return clib_error_return (0,
-                             "out2in dpo mode available only for simple nat");
-
-  /* for show commands, etc. */
-  sm->translation_buckets = translation_buckets;
-  sm->translation_memory_size = translation_memory_size;
-  /* do not exceed load factor 10 */
-  sm->max_translations = 10 * translation_buckets;
-  sm->user_buckets = user_buckets;
-  sm->user_memory_size = user_memory_size;
-  sm->max_translations_per_user = max_translations_per_user;
-  sm->outside_vrf_id = outside_vrf_id;
-  sm->outside_fib_index = fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4,
-                                                            outside_vrf_id,
-                                                            FIB_SOURCE_PLUGIN_HI);
-  nm->outside_vrf_id = outside_ip6_vrf_id;
-  nm->outside_fib_index = fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP6,
-                                                            outside_ip6_vrf_id,
-                                                            FIB_SOURCE_PLUGIN_HI);
-  sm->inside_vrf_id = inside_vrf_id;
-  sm->inside_fib_index = fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4,
-                                                           inside_vrf_id,
-                                                           FIB_SOURCE_PLUGIN_HI);
-  sm->static_mapping_only = static_mapping_only;
-  sm->static_mapping_connection_tracking = static_mapping_connection_tracking;
-
-  nat64_set_hash (nat64_bib_buckets, nat64_bib_memory_size, nat64_st_buckets,
-                 nat64_st_memory_size);
-
-  if (sm->deterministic)
-    {
-      sm->in2out_node_index = snat_det_in2out_node.index;
-      sm->in2out_output_node_index = ~0;
-      sm->out2in_node_index = snat_det_out2in_node.index;
-      sm->icmp_match_in2out_cb = icmp_match_in2out_det;
-      sm->icmp_match_out2in_cb = icmp_match_out2in_det;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  snat_user_t *u;
+  snat_session_t *s;
+  clib_bihash_kv_8_8_t kv;
+  vlib_main_t *vm = vlib_get_main ();
+  f64 now = vlib_time_now (vm);
+  nat_outside_fib_t *outside_fib;
+  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
+  fib_prefix_t pfx = {
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_len = 32,
+    .fp_addr = {
+               .ip4.as_u32 = eh_addr->as_u32,
+               },
+  };
+
+  if (!(flags & SNAT_SESSION_FLAG_STATIC_MAPPING))
+    {
+      if (nat_set_outside_address_and_port
+         (sm->addresses, thread_index, *out_addr, out_port, proto))
+       return;
     }
-  else
+
+  u = nat_user_get_or_create (sm, in_addr, fib_index, thread_index);
+  if (!u)
+    return;
+
+  s = nat_session_alloc_or_recycle (sm, u, thread_index, now);
+  if (!s)
+    return;
+
+  if (sm->endpoint_dependent)
     {
-      if (sm->endpoint_dependent)
-       {
-         sm->worker_in2out_cb = snat_get_worker_in2out_cb;
-         sm->worker_out2in_cb = nat44_ed_get_worker_out2in_cb;
-         sm->in2out_node_index = nat44_ed_in2out_node.index;
-         sm->in2out_output_node_index = nat44_ed_in2out_output_node.index;
-         sm->out2in_node_index = nat44_ed_out2in_node.index;
-         sm->icmp_match_in2out_cb = icmp_match_in2out_ed;
-         sm->icmp_match_out2in_cb = icmp_match_out2in_ed;
-         nat_affinity_init (vm);
-       }
-      else
-       {
-         sm->worker_in2out_cb = snat_get_worker_in2out_cb;
-         sm->worker_out2in_cb = snat_get_worker_out2in_cb;
-         sm->in2out_node_index = snat_in2out_node.index;
-         sm->in2out_output_node_index = snat_in2out_output_node.index;
-         sm->out2in_node_index = snat_out2in_node.index;
-         sm->icmp_match_in2out_cb = icmp_match_in2out_slow;
-         sm->icmp_match_out2in_cb = icmp_match_out2in_slow;
-       }
-      if (!static_mapping_only ||
-         (static_mapping_only && static_mapping_connection_tracking))
-       {
-          /* *INDENT-OFF* */
-          vec_foreach (tsm, sm->per_thread_data)
+      nat_ed_lru_insert (tsm, s, now, nat_proto_to_ip_proto (proto));
+    }
+
+  s->out2in.addr.as_u32 = out_addr->as_u32;
+  s->out2in.port = out_port;
+  s->nat_proto = proto;
+  s->last_heard = now;
+  s->flags = flags;
+  s->ext_host_addr.as_u32 = eh_addr->as_u32;
+  s->ext_host_port = eh_port;
+  user_session_increment (sm, u, snat_is_session_static (s));
+  switch (vec_len (sm->outside_fibs))
+    {
+    case 0:
+      s->out2in.fib_index = sm->outside_fib_index;
+      break;
+    case 1:
+      s->out2in.fib_index = sm->outside_fibs[0].fib_index;
+      break;
+    default:
+      /* *INDENT-OFF* */
+      vec_foreach (outside_fib, sm->outside_fibs)
+        {
+          fei = fib_table_lookup (outside_fib->fib_index, &pfx);
+          if (FIB_NODE_INDEX_INVALID != fei)
             {
-              if (sm->endpoint_dependent)
+              if (fib_entry_get_resolving_interface (fei) != ~0)
                 {
-                  clib_bihash_init_16_8 (&tsm->in2out_ed, "in2out-ed",
-                                         translation_buckets,
-                                         translation_memory_size);
-                  clib_bihash_set_kvp_format_fn_16_8 (&tsm->in2out_ed,
-                                                      format_ed_session_kvp);
-
-                  clib_bihash_init_16_8 (&tsm->out2in_ed, "out2in-ed",
-                                         translation_buckets,
-                                         translation_memory_size);
-                  clib_bihash_set_kvp_format_fn_16_8 (&tsm->out2in_ed,
-                                                      format_ed_session_kvp);
+                  s->out2in.fib_index = outside_fib->fib_index;
+                  break;
                 }
-              else
+            }
+        }
+      /* *INDENT-ON* */
+      break;
+    }
+  init_nat_o2i_kv (&kv, s, s - tsm->sessions);
+  if (clib_bihash_add_del_8_8 (&tsm->out2in, &kv, 1))
+    nat_elog_warn ("out2in key add failed");
+
+  s->in2out.addr.as_u32 = in_addr->as_u32;
+  s->in2out.port = in_port;
+  s->in2out.fib_index = fib_index;
+  init_nat_i2o_kv (&kv, s, s - tsm->sessions);
+  if (clib_bihash_add_del_8_8 (&tsm->in2out, &kv, 1))
+    nat_elog_warn ("in2out key add failed");
+}
+
+void
+nat_ha_sdel_cb (ip4_address_t * out_addr, u16 out_port,
+               ip4_address_t * eh_addr, u16 eh_port, u8 proto, u32 fib_index,
+               u32 ti)
+{
+  snat_main_t *sm = &snat_main;
+  clib_bihash_kv_8_8_t kv, value;
+  u32 thread_index;
+  snat_session_t *s;
+  snat_main_per_thread_data_t *tsm;
+
+  if (sm->num_workers > 1)
+    thread_index =
+      sm->first_worker_index +
+      (sm->workers[(clib_net_to_host_u16 (out_port) -
+                   1024) / sm->port_per_thread]);
+  else
+    thread_index = sm->num_workers;
+  tsm = vec_elt_at_index (sm->per_thread_data, thread_index);
+
+  init_nat_k (&kv, *out_addr, out_port, fib_index, proto);
+  if (clib_bihash_search_8_8 (&tsm->out2in, &kv, &value))
+    return;
+
+  s = pool_elt_at_index (tsm->sessions, value.value);
+  nat_free_session_data (sm, s, thread_index, 1);
+  nat44_delete_session (sm, s, thread_index);
+}
+
+void
+nat_ha_sref_cb (ip4_address_t * out_addr, u16 out_port,
+               ip4_address_t * eh_addr, u16 eh_port, u8 proto, u32 fib_index,
+               u32 total_pkts, u64 total_bytes, u32 thread_index)
+{
+  snat_main_t *sm = &snat_main;
+  clib_bihash_kv_8_8_t kv, value;
+  snat_session_t *s;
+  snat_main_per_thread_data_t *tsm;
+
+  tsm = vec_elt_at_index (sm->per_thread_data, thread_index);
+
+  init_nat_k (&kv, *out_addr, out_port, fib_index, proto);
+  if (clib_bihash_search_8_8 (&tsm->out2in, &kv, &value))
+    return;
+
+  s = pool_elt_at_index (tsm->sessions, value.value);
+  s->total_pkts = total_pkts;
+  s->total_bytes = total_bytes;
+}
+
+void
+nat_ha_sadd_ed_cb (ip4_address_t * in_addr, u16 in_port,
+                  ip4_address_t * out_addr, u16 out_port,
+                  ip4_address_t * eh_addr, u16 eh_port,
+                  ip4_address_t * ehn_addr, u16 ehn_port, u8 proto,
+                  u32 fib_index, u16 flags, u32 thread_index)
+{
+  snat_main_t *sm = &snat_main;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  snat_session_t *s;
+  clib_bihash_kv_16_8_t kv;
+  vlib_main_t *vm = vlib_get_main ();
+  f64 now = vlib_time_now (vm);
+  nat_outside_fib_t *outside_fib;
+  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
+  fib_prefix_t pfx = {
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_len = 32,
+    .fp_addr = {
+               .ip4.as_u32 = eh_addr->as_u32,
+               },
+  };
+
+
+  if (!(flags & SNAT_SESSION_FLAG_STATIC_MAPPING))
+    {
+      if (nat_set_outside_address_and_port
+         (sm->addresses, thread_index, *out_addr, out_port, proto))
+       return;
+    }
+
+  if (flags & SNAT_SESSION_FLAG_TWICE_NAT)
+    {
+      if (nat_set_outside_address_and_port
+         (sm->addresses, thread_index, *ehn_addr, ehn_port, proto))
+       return;
+    }
+
+  s = nat_ed_session_alloc (sm, thread_index, now, proto);
+  if (!s)
+    return;
+
+  s->last_heard = now;
+  s->flags = flags;
+  s->ext_host_nat_addr.as_u32 = s->ext_host_addr.as_u32 = eh_addr->as_u32;
+  s->ext_host_nat_port = s->ext_host_port = eh_port;
+  if (is_twice_nat_session (s))
+    {
+      s->ext_host_nat_addr.as_u32 = ehn_addr->as_u32;
+      s->ext_host_nat_port = ehn_port;
+    }
+  switch (vec_len (sm->outside_fibs))
+    {
+    case 0:
+      s->out2in.fib_index = sm->outside_fib_index;
+      break;
+    case 1:
+      s->out2in.fib_index = sm->outside_fibs[0].fib_index;
+      break;
+    default:
+      /* *INDENT-OFF* */
+      vec_foreach (outside_fib, sm->outside_fibs)
+        {
+          fei = fib_table_lookup (outside_fib->fib_index, &pfx);
+          if (FIB_NODE_INDEX_INVALID != fei)
+            {
+              if (fib_entry_get_resolving_interface (fei) != ~0)
                 {
-                  clib_bihash_init_8_8 (&tsm->in2out, "in2out",
-                                        translation_buckets,
-                                        translation_memory_size);
-                  clib_bihash_set_kvp_format_fn_8_8 (&tsm->in2out,
-                                                     format_session_kvp);
-
-                  clib_bihash_init_8_8 (&tsm->out2in, "out2in",
-                                        translation_buckets,
-                                        translation_memory_size);
-                  clib_bihash_set_kvp_format_fn_8_8 (&tsm->out2in,
-                                                     format_session_kvp);
+                  s->out2in.fib_index = outside_fib->fib_index;
+                  break;
                 }
-
-              clib_bihash_init_8_8 (&tsm->user_hash, "users", user_buckets,
-                                    user_memory_size);
-              clib_bihash_set_kvp_format_fn_8_8 (&tsm->user_hash,
-                                                 format_user_kvp);
             }
-          /* *INDENT-ON* */
+        }
+      /* *INDENT-ON* */
+      break;
+    }
+  s->nat_proto = proto;
+  s->out2in.addr.as_u32 = out_addr->as_u32;
+  s->out2in.port = out_port;
+
+  s->in2out.addr.as_u32 = in_addr->as_u32;
+  s->in2out.port = in_port;
+  s->in2out.fib_index = fib_index;
+
+  init_ed_kv (&kv, *in_addr, in_port, s->ext_host_nat_addr,
+             s->ext_host_nat_port, fib_index, nat_proto_to_ip_proto (proto),
+             thread_index, s - tsm->sessions);
+  if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &kv, 1))
+    nat_elog_warn ("in2out key add failed");
+
+  init_ed_kv (&kv, *out_addr, out_port, *eh_addr, eh_port,
+             s->out2in.fib_index, nat_proto_to_ip_proto (proto),
+             thread_index, s - tsm->sessions);
+  if (clib_bihash_add_del_16_8 (&sm->out2in_ed, &kv, 1))
+    nat_elog_warn ("out2in key add failed");
+}
 
-       }
-      else
+void
+nat_ha_sdel_ed_cb (ip4_address_t * out_addr, u16 out_port,
+                  ip4_address_t * eh_addr, u16 eh_port, u8 proto,
+                  u32 fib_index, u32 ti)
+{
+  snat_main_t *sm = &snat_main;
+  clib_bihash_kv_16_8_t kv, value;
+  u32 thread_index;
+  snat_session_t *s;
+  snat_main_per_thread_data_t *tsm;
+
+  if (sm->num_workers > 1)
+    thread_index =
+      sm->first_worker_index +
+      (sm->workers[(clib_net_to_host_u16 (out_port) -
+                   1024) / sm->port_per_thread]);
+  else
+    thread_index = sm->num_workers;
+  tsm = vec_elt_at_index (sm->per_thread_data, thread_index);
+
+  init_ed_k (&kv, *out_addr, out_port, *eh_addr, eh_port, fib_index, proto);
+  if (clib_bihash_search_16_8 (&sm->out2in_ed, &kv, &value))
+    return;
+
+  s = pool_elt_at_index (tsm->sessions, ed_value_get_session_index (&value));
+  nat_free_session_data (sm, s, thread_index, 1);
+  nat44_delete_session (sm, s, thread_index);
+}
+
+void
+nat_ha_sref_ed_cb (ip4_address_t * out_addr, u16 out_port,
+                  ip4_address_t * eh_addr, u16 eh_port, u8 proto,
+                  u32 fib_index, u32 total_pkts, u64 total_bytes,
+                  u32 thread_index)
+{
+  snat_main_t *sm = &snat_main;
+  clib_bihash_kv_16_8_t kv, value;
+  snat_session_t *s;
+  snat_main_per_thread_data_t *tsm;
+
+  tsm = vec_elt_at_index (sm->per_thread_data, thread_index);
+
+  init_ed_k (&kv, *out_addr, out_port, *eh_addr, eh_port, fib_index, proto);
+  if (clib_bihash_search_16_8 (&sm->out2in_ed, &kv, &value))
+    return;
+
+  s = pool_elt_at_index (tsm->sessions, ed_value_get_session_index (&value));
+  s->total_pkts = total_pkts;
+  s->total_bytes = total_bytes;
+}
+
+static u32
+nat_calc_bihash_buckets (u32 n_elts)
+{
+  n_elts = n_elts / 2.5;
+  u64 lower_pow2 = 1;
+  while (lower_pow2 * 2 < n_elts)
+    {
+      lower_pow2 = 2 * lower_pow2;
+    }
+  u64 upper_pow2 = 2 * lower_pow2;
+  if ((upper_pow2 - n_elts) < (n_elts - lower_pow2))
+    {
+      if (upper_pow2 <= UINT32_MAX)
        {
-         sm->icmp_match_in2out_cb = icmp_match_in2out_fast;
-         sm->icmp_match_out2in_cb = icmp_match_out2in_fast;
+         return upper_pow2;
        }
-      clib_bihash_init_8_8 (&sm->static_mapping_by_local,
-                           "static_mapping_by_local", static_mapping_buckets,
-                           static_mapping_memory_size);
-      clib_bihash_set_kvp_format_fn_8_8 (&sm->static_mapping_by_local,
-                                        format_static_mapping_kvp);
+    }
+  return lower_pow2;
+}
+
+u32
+nat44_get_max_session_limit ()
+{
+  snat_main_t *sm = &snat_main;
+  u32 max_limit = 0, len = 0;
+
+  for (; len < vec_len (sm->max_translations_per_fib); len++)
+    {
+      if (max_limit < sm->max_translations_per_fib[len])
+       max_limit = sm->max_translations_per_fib[len];
+    }
+  return max_limit;
+}
+
+int
+nat44_set_session_limit (u32 session_limit, u32 vrf_id)
+{
+  snat_main_t *sm = &snat_main;
+  u32 fib_index = fib_table_find (FIB_PROTOCOL_IP4, vrf_id);
+  u32 len = vec_len (sm->max_translations_per_fib);
+
+  if (len <= fib_index)
+    {
+      vec_validate (sm->max_translations_per_fib, fib_index + 1);
 
-      clib_bihash_init_8_8 (&sm->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_external,
-                                        format_static_mapping_kvp);
+      for (; len < vec_len (sm->max_translations_per_fib); len++)
+       sm->max_translations_per_fib[len] = sm->max_translations_per_thread;
     }
 
+  sm->max_translations_per_fib[fib_index] = session_limit;
+  return 0;
+}
+
+int
+nat44_update_session_limit (u32 session_limit, u32 vrf_id)
+{
+  snat_main_t *sm = &snat_main;
+
+  if (nat44_set_session_limit (session_limit, vrf_id))
+    return 1;
+  sm->max_translations_per_thread = nat44_get_max_session_limit ();
+
+  sm->translation_buckets =
+    nat_calc_bihash_buckets (sm->max_translations_per_thread);
+
+  nat44_sessions_clear ();
   return 0;
 }
 
-VLIB_CONFIG_FUNCTION (snat_config, "nat");
+void
+nat44_db_init (snat_main_per_thread_data_t * tsm)
+{
+  snat_main_t *sm = &snat_main;
+
+  pool_alloc (tsm->sessions, sm->max_translations_per_thread);
+  pool_alloc (tsm->lru_pool, sm->max_translations_per_thread);
+
+  dlist_elt_t *head;
+
+  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 (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 (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 (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 (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);
+
+  if (sm->endpoint_dependent)
+    {
+      clib_bihash_init_16_8 (&tsm->in2out_ed, "in2out-ed",
+                            sm->translation_buckets, 0);
+      clib_bihash_set_kvp_format_fn_16_8 (&tsm->in2out_ed,
+                                         format_ed_session_kvp);
+      /*
+         clib_bihash_init_16_8 (&sm->out2in_ed, "out2in-ed",
+         sm->translation_buckets, 0);
+         clib_bihash_set_kvp_format_fn_16_8 (&sm->out2in_ed,
+         format_ed_session_kvp); */
+    }
+  else
+    {
+      clib_bihash_init_8_8 (&tsm->in2out, "in2out", sm->translation_buckets,
+                           0);
+      clib_bihash_set_kvp_format_fn_8_8 (&tsm->in2out, format_session_kvp);
+      clib_bihash_init_8_8 (&tsm->out2in, "out2in", sm->translation_buckets,
+                           0);
+      clib_bihash_set_kvp_format_fn_8_8 (&tsm->out2in, format_session_kvp);
+    }
+
+  // TODO: ED nat is not using these
+  // before removal large refactor required
+  pool_alloc (tsm->list_pool, sm->max_translations_per_thread);
+  clib_bihash_init_8_8 (&tsm->user_hash, "users", sm->user_buckets, 0);
+  clib_bihash_set_kvp_format_fn_8_8 (&tsm->user_hash, format_user_kvp);
+}
+
+void
+nat44_db_free (snat_main_per_thread_data_t * tsm)
+{
+  snat_main_t *sm = &snat_main;
+
+  pool_free (tsm->sessions);
+  pool_free (tsm->lru_pool);
+
+  if (sm->endpoint_dependent)
+    {
+      clib_bihash_free_16_8 (&tsm->in2out_ed);
+      vec_free (tsm->per_vrf_sessions_vec);
+    }
+  else
+    {
+      clib_bihash_free_8_8 (&tsm->in2out);
+      clib_bihash_free_8_8 (&tsm->out2in);
+    }
+
+  // TODO: resolve static mappings (put only to !ED)
+  pool_free (tsm->users);
+  pool_free (tsm->list_pool);
+  clib_bihash_free_8_8 (&tsm->user_hash);
+}
+
+void
+nat44_sessions_clear ()
+{
+  snat_main_t *sm = &snat_main;
+  snat_main_per_thread_data_t *tsm;
+
+  if (sm->endpoint_dependent)
+    {
+      clib_bihash_free_16_8 (&sm->out2in_ed);
+      clib_bihash_init_16_8 (&sm->out2in_ed, "out2in-ed",
+                            clib_max (1,
+                                      sm->num_workers) *
+                            sm->translation_buckets, 0);
+      clib_bihash_set_kvp_format_fn_16_8 (&sm->out2in_ed,
+                                         format_ed_session_kvp);
+    }
+
+  /* *INDENT-OFF* */
+  vec_foreach (tsm, sm->per_thread_data)
+    {
+      u32 ti;
+
+      nat44_db_free (tsm);
+      nat44_db_init (tsm);
+
+      ti = tsm->snat_thread_index;
+      vlib_set_simple_counter (&sm->total_users, ti, 0, 0);
+      vlib_set_simple_counter (&sm->total_sessions, ti, 0, 0);
+    }
+  /* *INDENT-ON* */
+}
 
 static void
 nat_ip4_add_del_addr_only_sm_cb (ip4_main_t * im,
@@ -3156,11 +4411,13 @@ nat_ip4_add_del_addr_only_sm_cb (ip4_main_t * im,
   snat_main_t *sm = &snat_main;
   snat_static_map_resolve_t *rp;
   snat_static_mapping_t *m;
-  snat_session_key_t m_key;
   clib_bihash_kv_8_8_t kv, value;
   int i, rv;
   ip4_address_t l_addr;
 
+  if (!sm->enabled)
+    return;
+
   for (i = 0; i < vec_len (sm->to_resolve); i++)
     {
       rp = sm->to_resolve + i;
@@ -3173,11 +4430,8 @@ nat_ip4_add_del_addr_only_sm_cb (ip4_main_t * im,
   return;
 
 match:
-  m_key.addr.as_u32 = address->as_u32;
-  m_key.port = rp->addr_only ? 0 : rp->e_port;
-  m_key.protocol = rp->addr_only ? 0 : rp->proto;
-  m_key.fib_index = sm->outside_fib_index;
-  kv.key = m_key.as_u64;
+  init_nat_k (&kv, *address, rp->addr_only ? 0 : rp->e_port,
+             sm->outside_fib_index, rp->addr_only ? 0 : rp->proto);
   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
     m = 0;
   else
@@ -3208,9 +4462,10 @@ match:
                                rp->vrf_id,
                                rp->addr_only, ~0 /* sw_if_index */ ,
                                rp->proto, !is_delete, rp->twice_nat,
-                               rp->out2in_only, rp->tag, rp->identity_nat);
+                               rp->out2in_only, rp->tag, rp->identity_nat,
+                               rp->pool_addr, rp->exact);
   if (rv)
-    nat_log_notice ("snat_add_static_mapping returned %d", rv);
+    nat_elog_notice_X1 ("snat_add_static_mapping returned %d", "i4", rv);
 }
 
 static void
@@ -3229,6 +4484,9 @@ snat_ip4_add_del_interface_address_cb (ip4_main_t * im,
   u8 twice_nat = 0;
   snat_address_t *addresses = sm->addresses;
 
+  if (!sm->enabled)
+    return;
+
   for (i = 0; i < vec_len (sm->auto_add_sw_if_indices); i++)
     {
       if (sw_if_index == sm->auto_add_sw_if_indices[i])
@@ -3279,9 +4537,11 @@ match:
                                            rp->proto,
                                            rp->is_add, rp->twice_nat,
                                            rp->out2in_only, rp->tag,
-                                           rp->identity_nat);
+                                           rp->identity_nat,
+                                           rp->pool_addr, rp->exact);
              if (rv)
-               nat_log_notice ("snat_add_static_mapping returned %d", rv);
+               nat_elog_notice_X1 ("snat_add_static_mapping returned %d",
+                                   "i4", rv);
            }
        }
       return;
@@ -3293,7 +4553,6 @@ match:
     }
 }
 
-
 int
 snat_add_interface_address (snat_main_t * sm, u32 sw_if_index, int is_del,
                            u8 twice_nat)
@@ -3364,13 +4623,12 @@ snat_add_interface_address (snat_main_t * sm, u32 sw_if_index, int is_del,
 
 int
 nat44_del_session (snat_main_t * sm, ip4_address_t * addr, u16 port,
-                  snat_protocol_t proto, u32 vrf_id, int is_in)
+                  nat_protocol_t proto, u32 vrf_id, int is_in)
 {
   snat_main_per_thread_data_t *tsm;
   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_key_t key;
   snat_session_t *s;
   clib_bihash_8_8_t *t;
 
@@ -3381,15 +4639,11 @@ nat44_del_session (snat_main_t * sm, ip4_address_t * addr, u16 port,
   if (sm->num_workers > 1)
     tsm =
       vec_elt_at_index (sm->per_thread_data,
-                       sm->worker_in2out_cb (&ip, fib_index));
+                       sm->worker_in2out_cb (&ip, fib_index, 0));
   else
     tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
 
-  key.addr.as_u32 = addr->as_u32;
-  key.port = clib_host_to_net_u16 (port);
-  key.protocol = proto;
-  key.fib_index = fib_index;
-  kv.key = key.as_u64;
+  init_nat_k (&kv, *addr, port, fib_index, proto);
   t = is_in ? &tsm->in2out : &tsm->out2in;
   if (!clib_bihash_search_8_8 (t, &kv, &value))
     {
@@ -3397,7 +4651,7 @@ nat44_del_session (snat_main_t * sm, ip4_address_t * addr, u16 port,
        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);
+      nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
       nat44_delete_session (sm, s, tsm - sm->per_thread_data);
       return 0;
     }
@@ -3412,7 +4666,6 @@ nat44_del_ed_session (snat_main_t * sm, ip4_address_t * addr, u16 port,
 {
   ip4_header_t ip;
   clib_bihash_16_8_t *t;
-  nat_ed_ses_key_t key;
   clib_bihash_kv_16_8_t kv, value;
   u32 fib_index = fib_table_find (FIB_PROTOCOL_IP4, vrf_id);
   snat_session_t *s;
@@ -3425,27 +4678,22 @@ nat44_del_ed_session (snat_main_t * sm, ip4_address_t * addr, u16 port,
   if (sm->num_workers > 1)
     tsm =
       vec_elt_at_index (sm->per_thread_data,
-                       sm->worker_in2out_cb (&ip, fib_index));
+                       sm->worker_in2out_cb (&ip, fib_index, 0));
   else
     tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
 
-  t = is_in ? &tsm->in2out_ed : &tsm->out2in_ed;
-  key.l_addr.as_u32 = addr->as_u32;
-  key.r_addr.as_u32 = eh_addr->as_u32;
-  key.l_port = clib_host_to_net_u16 (port);
-  key.r_port = clib_host_to_net_u16 (eh_port);
-  key.proto = proto;
-  key.fib_index = fib_index;
-  kv.key[0] = key.as_u64[0];
-  kv.key[1] = key.as_u64[1];
+  t = is_in ? &tsm->in2out_ed : &sm->out2in_ed;
+  init_ed_k (&kv, *addr, port, *eh_addr, eh_port, fib_index, proto);
   if (clib_bihash_search_16_8 (t, &kv, &value))
-    return VNET_API_ERROR_NO_SUCH_ENTRY;
+    {
+      return VNET_API_ERROR_NO_SUCH_ENTRY;
+    }
 
   if (pool_is_free_index (tsm->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);
-  nat44_delete_session (sm, s, tsm - sm->per_thread_data);
+  nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+  nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
   return 0;
 }
 
@@ -3481,6 +4729,36 @@ nat_set_alloc_addr_and_port_default (void)
   sm->alloc_addr_and_port = nat_alloc_addr_and_port_default;
 }
 
+VLIB_NODE_FN (nat_default_node) (vlib_main_t * vm,
+                                vlib_node_runtime_t * node,
+                                vlib_frame_t * frame)
+{
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat_default_node) = {
+  .name = "nat-default",
+  .vector_size = sizeof (u32),
+  .format_trace = 0,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = 0,
+  .n_next_nodes = NAT_N_NEXT,
+  .next_nodes = {
+    [NAT_NEXT_DROP] = "error-drop",
+    [NAT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT_NEXT_IN2OUT_ED_FAST_PATH] = "nat44-ed-in2out",
+    [NAT_NEXT_IN2OUT_ED_SLOW_PATH] = "nat44-ed-in2out-slowpath",
+    [NAT_NEXT_IN2OUT_ED_OUTPUT_FAST_PATH] = "nat44-ed-in2out-output",
+    [NAT_NEXT_IN2OUT_ED_OUTPUT_SLOW_PATH] = "nat44-ed-in2out-output-slowpath",
+    [NAT_NEXT_OUT2IN_ED_FAST_PATH] = "nat44-ed-out2in",
+    [NAT_NEXT_OUT2IN_ED_SLOW_PATH] = "nat44-ed-out2in-slowpath",
+    [NAT_NEXT_IN2OUT_CLASSIFY] = "nat44-in2out-worker-handoff",
+    [NAT_NEXT_OUT2IN_CLASSIFY] = "nat44-out2in-worker-handoff",
+  },
+};
+/* *INDENT-ON* */
+
 /*
  * fd.io coding-style-patch-verification: ON
  *