nat: reduce number of hash tables for EI NAT

Making code more simple and storing thread index along with session
index as a preparation step for fixing thread safety patches.

Type: improvement
Signed-off-by: Klement Sekera <ksekera@cisco.com>
Change-Id: Ib0c531e9f1f64b1f1ee912d4a83279200638e931

9 files changed, 141 insertions, 141 deletions

diff --git a/src/plugins/nat/nat.c b/src/plugins/nat/nat.c
index 245689db45d..57d3b2bfdd1 100644
--- a/src/plugins/nat/nat.c
+++ b/src/plugins/nat/nat.c
@@ -217,7 +217,9 @@ 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);
+  s = format (s, "%U thread-index %llu session-index %llu", format_snat_key,
+	      v->key, nat_value_get_thread_index (v),
+	      nat_value_get_session_index (v));
 
   return s;
 }
@@ -274,8 +276,6 @@ nat_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);
 
   if (is_ed_session (s))
     {
@@ -311,10 +311,10 @@ nat_free_session_data (snat_main_t * sm, snat_session_t * s, u32 thread_index,
   else
     {
       init_nat_i2o_k (&kv, s);
-      if (clib_bihash_add_del_8_8 (&tsm->in2out, &kv, 0))
+      if (clib_bihash_add_del_8_8 (&sm->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))
+      if (clib_bihash_add_del_8_8 (&sm->out2in, &kv, 0))
 	nat_elog_warn ("out2in key del failed");
 
       if (!is_ha)
@@ -833,9 +833,8 @@ nat44_ed_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 	      local->fib_index =
 		fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP4, vrf_id,
 						   sm->fib_src_low);
-	      init_nat_kv (&kv, m->local_addr, m->local_port,
-			   local->fib_index, m->proto,
-			   m - sm->static_mappings);
+	      init_nat_kv (&kv, m->local_addr, m->local_port, local->fib_index,
+			   m->proto, 0, m - sm->static_mappings);
 	      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
 	      return 0;
 	    }
@@ -974,11 +973,11 @@ nat44_ed_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       if (!out2in_only)
 	{
 	  init_nat_kv (&kv, m->local_addr, m->local_port, fib_index, m->proto,
-		       m - sm->static_mappings);
+		       0, m - sm->static_mappings);
 	  clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
 	}
 
-      init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto,
+      init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto, 0,
 		   m - sm->static_mappings);
       clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 1);
 
@@ -1268,7 +1267,7 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       else
 	m->affinity_per_service_list_head_index = ~0;
 
-      init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto,
+      init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto, 0,
 		   m - sm->static_mappings);
       if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 1))
 	{
@@ -1285,7 +1284,7 @@ nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 	  if (!out2in_only)
 	    {
 	      init_nat_kv (&kv, locals[i].addr, locals[i].port,
-			   locals[i].fib_index, m->proto,
+			   locals[i].fib_index, m->proto, 0,
 			   m - sm->static_mappings);
 	      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
 	    }
@@ -1471,7 +1470,7 @@ nat44_lb_static_mapping_add_del_local (ip4_address_t e_addr, u16 e_port,
 
       if (!is_out2in_only_static_mapping (m))
 	{
-	  init_nat_kv (&kv, l_addr, l_port, local->fib_index, proto,
+	  init_nat_kv (&kv, l_addr, l_port, local->fib_index, proto, 0,
 		       m - sm->static_mappings);
 	  if (clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1))
 	    nat_elog_err ("static_mapping_by_local key add failed");
@@ -1666,24 +1665,24 @@ snat_del_address (snat_main_t * sm, ip4_address_t addr, u8 delete_sm,
   vec_free (a->busy_##n##_ports_per_thread);
   foreach_nat_protocol
 #undef _
+
     if (twice_nat)
-    {
-      vec_del1 (sm->twice_nat_addresses, i);
-      return 0;
-    }
-  else
-    vec_del1 (sm->addresses, i);
+  {
+    vec_del1 (sm->twice_nat_addresses, i);
+    return 0;
+  }
+  else vec_del1 (sm->addresses, i);
 
   /* Delete external address from FIB */
-  /* *INDENT-OFF* */
   pool_foreach (interface, sm->interfaces)
-   {
-    if (nat_interface_is_inside(interface) || sm->out2in_dpo)
-      continue;
+    {
+      if (nat_interface_is_inside (interface) || sm->out2in_dpo)
+	continue;
+
+      snat_add_del_addr_to_fib (&addr, 32, interface->sw_if_index, 0);
+      break;
+    }
 
-    snat_add_del_addr_to_fib(&addr, 32, interface->sw_if_index, 0);
-    break;
-  }
   pool_foreach (interface, sm->output_feature_interfaces)
    {
     if (nat_interface_is_inside(interface) || sm->out2in_dpo)
@@ -1692,7 +1691,6 @@ snat_del_address (snat_main_t * sm, ip4_address_t addr, u8 delete_sm,
     snat_add_del_addr_to_fib(&addr, 32, interface->sw_if_index, 0);
     break;
   }
-  /* *INDENT-ON* */
 
   return 0;
 }
diff --git a/src/plugins/nat/nat.h b/src/plugins/nat/nat.h
index 7fa1ef79c3d..86f6342ab09 100644
--- a/src/plugins/nat/nat.h
+++ b/src/plugins/nat/nat.h
@@ -492,10 +492,6 @@ typedef struct
 
 typedef struct
 {
-  /* Main lookup tables */
-  clib_bihash_8_8_t out2in;
-  clib_bihash_8_8_t in2out;
-
   /* Find-a-user => src address lookup */
   clib_bihash_8_8_t user_hash;
 
@@ -590,6 +586,10 @@ typedef struct snat_main_s
   /* Static mapping pool */
   snat_static_mapping_t *static_mappings;
 
+  /* Endpoint independent lookup tables */
+  clib_bihash_8_8_t in2out;
+  clib_bihash_8_8_t out2in;
+
   /* Endpoint dependent lookup table */
   clib_bihash_16_8_t flow_hash;
 
diff --git a/src/plugins/nat/nat44-ei/nat44_ei.c b/src/plugins/nat/nat44-ei/nat44_ei.c
index 00aa8e1b65b..34288e14856 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei.c
@@ -194,15 +194,12 @@ nat44_ei_free_session_data (snat_main_t *sm, snat_session_t *s,
 {
   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))
+  if (clib_bihash_add_del_8_8 (&sm->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))
+  if (clib_bihash_add_del_8_8 (&sm->out2in, &kv, 0))
     nat_elog_warn ("out2in key del failed");
 
   if (!is_ha)
@@ -709,7 +706,7 @@ nat44_ei_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
     tsm = vec_elt_at_index (sm->per_thread_data, sm->num_workers);
 
   init_nat_k (&kv, *addr, port, fib_index, proto);
-  t = is_in ? &tsm->in2out : &tsm->out2in;
+  t = is_in ? &sm->in2out : &sm->out2in;
   if (!clib_bihash_search_8_8 (t, &kv, &value))
     {
       if (pool_is_free_index (tsm->sessions, value.value))
@@ -832,7 +829,7 @@ nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 	      local->fib_index = fib_table_find_or_create_and_lock (
 		FIB_PROTOCOL_IP4, vrf_id, sm->fib_src_low);
 	      init_nat_kv (&kv, m->local_addr, m->local_port, local->fib_index,
-			   m->proto, m - sm->static_mappings);
+			   m->proto, 0, m - sm->static_mappings);
 	      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
 	      return 0;
 	    }
@@ -956,11 +953,11 @@ nat44_ei_add_del_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);
 
-      init_nat_kv (&kv, m->local_addr, m->local_port, fib_index, m->proto,
+      init_nat_kv (&kv, m->local_addr, m->local_port, fib_index, m->proto, 0,
 		   m - sm->static_mappings);
       clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 1);
 
-      init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto,
+      init_nat_kv (&kv, m->external_addr, m->external_port, 0, m->proto, 0,
 		   m - sm->static_mappings);
       clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 1);
 
@@ -1191,8 +1188,6 @@ nat44_ei_worker_db_free (snat_main_per_thread_data_t *tsm)
   pool_free (tsm->sessions);
   pool_free (tsm->users);
 
-  clib_bihash_free_8_8 (&tsm->in2out);
-  clib_bihash_free_8_8 (&tsm->out2in);
   clib_bihash_free_8_8 (&tsm->user_hash);
 }
 
@@ -1206,12 +1201,8 @@ nat44_ei_worker_db_init (snat_main_per_thread_data_t *tsm, u32 translations,
   pool_alloc (tsm->lru_pool, translations);
   pool_alloc (tsm->sessions, translations);
 
-  clib_bihash_init_8_8 (&tsm->in2out, "in2out", translation_buckets, 0);
-  clib_bihash_init_8_8 (&tsm->out2in, "out2in", translation_buckets, 0);
   clib_bihash_init_8_8 (&tsm->user_hash, "users", user_buckets, 0);
 
-  clib_bihash_set_kvp_format_fn_8_8 (&tsm->in2out, format_session_kvp);
-  clib_bihash_set_kvp_format_fn_8_8 (&tsm->out2in, format_session_kvp);
   clib_bihash_set_kvp_format_fn_8_8 (&tsm->user_hash, format_user_kvp);
 
   pool_get (tsm->lru_pool, head);
@@ -1247,6 +1238,8 @@ nat44_ei_db_free ()
 
   if (sm->pat)
     {
+      clib_bihash_free_8_8 (&sm->in2out);
+      clib_bihash_free_8_8 (&sm->out2in);
       vec_foreach (tsm, sm->per_thread_data)
 	{
 	  nat44_ei_worker_db_free (tsm);
@@ -1276,6 +1269,10 @@ nat44_ei_db_init (u32 translations, u32 translation_buckets, u32 user_buckets)
 
   if (sm->pat)
     {
+      clib_bihash_init_8_8 (&sm->in2out, "in2out", translation_buckets, 0);
+      clib_bihash_init_8_8 (&sm->out2in, "out2in", translation_buckets, 0);
+      clib_bihash_set_kvp_format_fn_8_8 (&sm->in2out, format_session_kvp);
+      clib_bihash_set_kvp_format_fn_8_8 (&sm->out2in, format_session_kvp);
       vec_foreach (tsm, sm->per_thread_data)
 	{
 	  nat44_ei_worker_db_init (tsm, translations, translation_buckets,
@@ -1294,6 +1291,12 @@ nat44_ei_sessions_clear ()
 
   if (sm->pat)
     {
+      clib_bihash_free_8_8 (&sm->in2out);
+      clib_bihash_free_8_8 (&sm->out2in);
+      clib_bihash_init_8_8 (&sm->in2out, "in2out", nm->translation_buckets, 0);
+      clib_bihash_init_8_8 (&sm->out2in, "out2in", nm->translation_buckets, 0);
+      clib_bihash_set_kvp_format_fn_8_8 (&sm->in2out, format_session_kvp);
+      clib_bihash_set_kvp_format_fn_8_8 (&sm->out2in, format_session_kvp);
       vec_foreach (tsm, sm->per_thread_data)
 	{
 	  nat44_ei_worker_db_free (tsm);
diff --git a/src/plugins/nat/nat44-ei/nat44_ei_ha.c b/src/plugins/nat/nat44-ei/nat44_ei_ha.c
index 0b904bf079b..aea758af2d4 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei_ha.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei_ha.c
@@ -241,15 +241,15 @@ nat44_ei_ha_sadd (ip4_address_t *in_addr, u16 in_port, ip4_address_t *out_addr,
 	}
       break;
     }
-  init_nat_o2i_kv (&kv, s, s - tsm->sessions);
-  if (clib_bihash_add_del_8_8 (&tsm->out2in, &kv, 1))
+  init_nat_o2i_kv (&kv, s, thread_index, s - tsm->sessions);
+  if (clib_bihash_add_del_8_8 (&sm->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))
+  init_nat_i2o_kv (&kv, s, thread_index, s - tsm->sessions);
+  if (clib_bihash_add_del_8_8 (&sm->in2out, &kv, 1))
     nat_elog_warn ("in2out key add failed");
 }
 
@@ -273,10 +273,10 @@ nat44_ei_ha_sdel (ip4_address_t *out_addr, u16 out_port,
   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))
+  if (clib_bihash_search_8_8 (&sm->out2in, &kv, &value))
     return;
 
-  s = pool_elt_at_index (tsm->sessions, value.value);
+  s = pool_elt_at_index (tsm->sessions, nat_value_get_session_index (&value));
   nat_free_session_data (sm, s, thread_index, 1);
   nat44_delete_session (sm, s, thread_index);
 }
@@ -294,10 +294,10 @@ nat44_ei_ha_sref (ip4_address_t *out_addr, u16 out_port,
   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))
+  if (clib_bihash_search_8_8 (&sm->out2in, &kv, &value))
     return;
 
-  s = pool_elt_at_index (tsm->sessions, value.value);
+  s = pool_elt_at_index (tsm->sessions, nat_value_get_session_index (&value));
   s->total_pkts = total_pkts;
   s->total_bytes = total_bytes;
 }
diff --git a/src/plugins/nat/nat44-ei/nat44_ei_in2out.c b/src/plugins/nat/nat44-ei/nat44_ei_in2out.c
index 303c588d34e..6a4658513d7 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei_in2out.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei_in2out.c
@@ -124,8 +124,7 @@ snat_not_translate (snat_main_t * sm, vlib_node_runtime_t * node,
 
   /* NAT packet aimed at external address if */
   /* has active sessions */
-  if (clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].out2in, &kv0,
-			      &value0))
+  if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
     {
       /* or is static mappings */
       ip4_address_t placeholder_addr;
@@ -159,15 +158,13 @@ nat_not_translate_output_feature (snat_main_t * sm, ip4_header_t * ip0,
   init_nat_k (&kv0, ip0->src_address, src_port,
 	      ip4_fib_table_get_index_for_sw_if_index (sw_if_index), proto0);
 
-  if (!clib_bihash_search_8_8
-      (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
+  if (!clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
     return 1;
 
   /* dst NAT check */
   init_nat_k (&kv0, ip0->dst_address, dst_port,
 	      ip4_fib_table_get_index_for_sw_if_index (sw_if_index), proto0);
-  if (!clib_bihash_search_8_8
-      (&sm->per_thread_data[thread_index].in2out, &kv0, &value0))
+  if (!clib_bihash_search_8_8 (&sm->in2out, &kv0, &value0))
     {
       /* hairpinning */
     /* *INDENT-OFF* */
@@ -200,7 +197,7 @@ nat44_i2o_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
   if (ctx->now >= sess_timeout_time)
     {
       init_nat_o2i_k (&s_kv, s);
-      if (clib_bihash_add_del_8_8 (&tsm->out2in, &s_kv, 0))
+      if (clib_bihash_add_del_8_8 (&sm->out2in, &s_kv, 0))
 	nat_elog_warn ("out2in key del failed");
 
       nat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
@@ -354,16 +351,16 @@ slow_path (snat_main_t * sm, vlib_buffer_t * b0,
   /* Add to translation hashes */
   ctx0.now = now;
   ctx0.thread_index = thread_index;
-  init_nat_i2o_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
-  if (clib_bihash_add_or_overwrite_stale_8_8
-      (&sm->per_thread_data[thread_index].in2out, &kv0,
-       nat44_i2o_is_idle_session_cb, &ctx0))
+  init_nat_i2o_kv (&kv0, s, thread_index,
+		   s - sm->per_thread_data[thread_index].sessions);
+  if (clib_bihash_add_or_overwrite_stale_8_8 (
+	&sm->in2out, &kv0, nat44_i2o_is_idle_session_cb, &ctx0))
     nat_elog_notice ("in2out key add failed");
 
-  init_nat_o2i_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
-  if (clib_bihash_add_or_overwrite_stale_8_8
-      (&sm->per_thread_data[thread_index].out2in, &kv0,
-       nat44_o2i_is_idle_session_cb, &ctx0))
+  init_nat_o2i_kv (&kv0, s, thread_index,
+		   s - sm->per_thread_data[thread_index].sessions);
+  if (clib_bihash_add_or_overwrite_stale_8_8 (
+	&sm->out2in, &kv0, nat44_o2i_is_idle_session_cb, &ctx0))
     nat_elog_notice ("out2in key add failed");
 
   /* log NAT event */
@@ -474,7 +471,7 @@ icmp_match_in2out_slow (snat_main_t * sm, vlib_node_runtime_t * node,
     }
 
   init_nat_k (&kv0, *addr, *port, *fib_index, *proto);
-  if (clib_bihash_search_8_8 (&tsm->in2out, &kv0, &value0))
+  if (clib_bihash_search_8_8 (&sm->in2out, &kv0, &value0))
     {
       if (vnet_buffer (b0)->sw_if_index[VLIB_TX] != ~0)
 	{
@@ -534,7 +531,8 @@ icmp_match_in2out_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 	  goto out;
 	}
 
-      s0 = pool_elt_at_index (tsm->sessions, value0.value);
+      s0 = pool_elt_at_index (tsm->sessions,
+			      nat_value_get_session_index (&value0));
     }
 
 out:
@@ -988,9 +986,8 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
       init_nat_k (&kv0, ip0->src_address,
 		  vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
 		  proto0);
-      if (PREDICT_FALSE
-	  (clib_bihash_search_8_8
-	   (&sm->per_thread_data[thread_index].in2out, &kv0, &value0) != 0))
+      if (PREDICT_FALSE (clib_bihash_search_8_8 (&sm->in2out, &kv0, &value0) !=
+			 0))
 	{
 	  if (is_slow_path)
 	    {
@@ -1043,9 +1040,8 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	    }
 	}
       else
-	s0 =
-	  pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-			     value0.value);
+	s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
+				nat_value_get_session_index (&value0));
 
       b0->flags |= VNET_BUFFER_F_IS_NATED;
 
@@ -1212,9 +1208,8 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
       init_nat_k (&kv1, ip1->src_address,
 		  vnet_buffer (b1)->ip.reass.l4_src_port, rx_fib_index1,
 		  proto1);
-      if (PREDICT_FALSE
-	  (clib_bihash_search_8_8
-	   (&sm->per_thread_data[thread_index].in2out, &kv1, &value1) != 0))
+      if (PREDICT_FALSE (clib_bihash_search_8_8 (&sm->in2out, &kv1, &value1) !=
+			 0))
 	{
 	  if (is_slow_path)
 	    {
@@ -1267,9 +1262,8 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	    }
 	}
       else
-	s1 =
-	  pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-			     value1.value);
+	s1 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
+				nat_value_get_session_index (&value1));
 
       b1->flags |= VNET_BUFFER_F_IS_NATED;
 
@@ -1463,8 +1457,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 		  vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
 		  proto0);
 
-      if (clib_bihash_search_8_8
-	  (&sm->per_thread_data[thread_index].in2out, &kv0, &value0))
+      if (clib_bihash_search_8_8 (&sm->in2out, &kv0, &value0))
 	{
 	  if (is_slow_path)
 	    {
@@ -1518,9 +1511,8 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 	    }
 	}
       else
-	s0 =
-	  pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-			     value0.value);
+	s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
+				nat_value_get_session_index (&value0));
 
       b0->flags |= VNET_BUFFER_F_IS_NATED;
 
diff --git a/src/plugins/nat/nat44-ei/nat44_ei_out2in.c b/src/plugins/nat/nat44-ei/nat44_ei_out2in.c
index b677e9bde89..f0b6427613a 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei_out2in.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei_out2in.c
@@ -116,7 +116,7 @@ nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
   if (ctx->now >= sess_timeout_time)
     {
       init_nat_i2o_k (&s_kv, s);
-      if (clib_bihash_add_del_8_8 (&tsm->in2out, &s_kv, 0))
+      if (clib_bihash_add_del_8_8 (&sm->in2out, &s_kv, 0))
 	nat_elog_warn ("out2in key del failed");
 
       nat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
@@ -222,16 +222,16 @@ create_session_for_static_mapping (snat_main_t * sm,
   /* Add to translation hashes */
   ctx0.now = now;
   ctx0.thread_index = thread_index;
-  init_nat_i2o_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
-  if (clib_bihash_add_or_overwrite_stale_8_8
-      (&sm->per_thread_data[thread_index].in2out, &kv0,
-       nat44_i2o_is_idle_session_cb, &ctx0))
+  init_nat_i2o_kv (&kv0, s, thread_index,
+		   s - sm->per_thread_data[thread_index].sessions);
+  if (clib_bihash_add_or_overwrite_stale_8_8 (
+	&sm->in2out, &kv0, nat44_i2o_is_idle_session_cb, &ctx0))
     nat_elog_notice ("in2out key add failed");
 
-  init_nat_o2i_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
-  if (clib_bihash_add_or_overwrite_stale_8_8
-      (&sm->per_thread_data[thread_index].out2in, &kv0,
-       nat44_o2i_is_idle_session_cb, &ctx0))
+  init_nat_o2i_kv (&kv0, s, thread_index,
+		   s - sm->per_thread_data[thread_index].sessions);
+  if (clib_bihash_add_or_overwrite_stale_8_8 (
+	&sm->out2in, &kv0, nat44_o2i_is_idle_session_cb, &ctx0))
     nat_elog_notice ("out2in key add failed");
 
   /* log NAT event */
@@ -351,7 +351,7 @@ icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
   u32 mapping_fib_index;
 
   init_nat_k (&kv0, *addr, *port, *fib_index, *proto);
-  if (clib_bihash_search_8_8 (&tsm->out2in, &kv0, &value0))
+  if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
     {
       /* Try to match static mapping by external address and port,
          destination address and port in packet */
@@ -423,7 +423,8 @@ icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 	  goto out;
 	}
 
-      s0 = pool_elt_at_index (tsm->sessions, value0.value);
+      s0 = pool_elt_at_index (tsm->sessions,
+			      nat_value_get_session_index (&value0));
     }
 
 out:
@@ -823,8 +824,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       init_nat_k (&kv0, ip0->dst_address,
 		  vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 		  proto0);
-      if (clib_bihash_search_8_8
-	  (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
+      if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
 	{
 	  /* Try to match static mapping by external address and port,
 	     destination address and port in packet */
@@ -873,7 +873,8 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	    }
 	}
       else
-	s0 = pool_elt_at_index (tsm->sessions, value0.value);
+	s0 = pool_elt_at_index (tsm->sessions,
+				nat_value_get_session_index (&value0));
 
       old_addr0 = ip0->dst_address.as_u32;
       ip0->dst_address = s0->in2out.addr;
@@ -1002,8 +1003,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
       init_nat_k (&kv1, ip1->dst_address,
 		  vnet_buffer (b1)->ip.reass.l4_dst_port, rx_fib_index1,
 		  proto1);
-      if (clib_bihash_search_8_8
-	  (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
+      if (clib_bihash_search_8_8 (&sm->out2in, &kv1, &value1))
 	{
 	  /* Try to match static mapping by external address and port,
 	     destination address and port in packet */
@@ -1052,9 +1052,8 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	    }
 	}
       else
-	s1 =
-	  pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-			     value1.value);
+	s1 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
+				nat_value_get_session_index (&value1));
 
       old_addr1 = ip1->dst_address.as_u32;
       ip1->dst_address = s1->in2out.addr;
@@ -1219,8 +1218,7 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 		  vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
 		  proto0);
 
-      if (clib_bihash_search_8_8
-	  (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
+      if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
 	{
 	  /* Try to match static mapping by external address and port,
 	     destination address and port in packet */
@@ -1269,9 +1267,8 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
 	    }
 	}
       else
-	s0 =
-	  pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-			     value0.value);
+	s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
+				nat_value_get_session_index (&value0));
 
       old_addr0 = ip0->dst_address.as_u32;
       ip0->dst_address = s0->in2out.addr;
diff --git a/src/plugins/nat/nat44_cli.c b/src/plugins/nat/nat44_cli.c
index d1a08718ed7..c89963ec85a 100644
--- a/src/plugins/nat/nat44_cli.c
+++ b/src/plugins/nat/nat44_cli.c
@@ -300,22 +300,20 @@ nat44_show_hash_command_fn (vlib_main_t * vm, unformat_input_t * input,
   vlib_cli_output (vm, "%U",
 		   format_bihash_8_8, &sm->static_mapping_by_external,
 		   verbose);
-  vlib_cli_output (vm, "%U", format_bihash_16_8, &sm->flow_hash, verbose);
+  if (sm->endpoint_dependent)
+    {
+      vlib_cli_output (vm, "%U", format_bihash_16_8, &sm->flow_hash, verbose);
+    }
+  else
+    {
+      vlib_cli_output (vm, "%U", format_bihash_8_8, &sm->in2out, verbose);
+      vlib_cli_output (vm, "%U", format_bihash_8_8, &sm->out2in, verbose);
+    }
   vec_foreach_index (i, sm->per_thread_data)
   {
     tsm = vec_elt_at_index (sm->per_thread_data, i);
     vlib_cli_output (vm, "-------- thread %d %s --------\n",
 		     i, vlib_worker_threads[i].name);
-    if (sm->endpoint_dependent)
-      {
-	vlib_cli_output (vm, "%U", format_bihash_16_8, &sm->flow_hash,
-			 verbose);
-      }
-    else
-      {
-	vlib_cli_output (vm, "%U", format_bihash_8_8, &tsm->in2out, verbose);
-	vlib_cli_output (vm, "%U", format_bihash_8_8, &tsm->out2in, verbose);
-      }
     vlib_cli_output (vm, "%U", format_bihash_8_8, &tsm->user_hash, verbose);
   }
 
diff --git a/src/plugins/nat/nat44_hairpinning.c b/src/plugins/nat/nat44_hairpinning.c
index 37dfd7827f6..f458909df20 100644
--- a/src/plugins/nat/nat44_hairpinning.c
+++ b/src/plugins/nat/nat44_hairpinning.c
@@ -129,15 +129,14 @@ snat_hairpinning (vlib_main_t *vm, vlib_node_runtime_t *node, snat_main_t *sm,
 
       init_nat_k (&kv0, ip0->dst_address, udp0->dst_port,
 		  sm->outside_fib_index, proto0);
-      rv = clib_bihash_search_8_8 (&sm->per_thread_data[ti].out2in, &kv0,
-				   &value0);
+      rv = clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0);
       if (rv)
 	{
 	  rv = 0;
 	  goto trace;
 	}
 
-      si = value0.value;
+      si = nat_value_get_session_index (&value0);
       s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
       new_dst_addr0 = s0->in2out.addr.as_u32;
       new_dst_port0 = s0->in2out.port;
@@ -249,10 +248,9 @@ snat_icmp_hairpinning (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
 
       init_nat_k (&kv0, ip0->dst_address, l4_header->src_port,
 		  sm->outside_fib_index, protocol);
-      if (clib_bihash_search_8_8 (&sm->per_thread_data[ti].out2in, &kv0,
-				  &value0))
+      if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
 	return 1;
-      si = value0.value;
+      si = nat_value_get_session_index (&value0);
       s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
       new_dst_addr0 = s0->in2out.addr.as_u32;
       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
@@ -290,8 +288,8 @@ snat_icmp_hairpinning (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
   else
     {
       init_nat_k (&kv0, ip0->dst_address, 0, sm->outside_fib_index, 0);
-      if (clib_bihash_search_8_8
-	  (&sm->static_mapping_by_external, &kv0, &value0))
+      if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv0,
+				  &value0))
 	{
 	  icmp_echo_header_t *echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 	  u16 icmp_id0 = echo0->identifier;
@@ -302,11 +300,10 @@ snat_icmp_hairpinning (snat_main_t *sm, vlib_buffer_t *b0, ip4_header_t *ip0,
 	      (clib_net_to_host_u16 (icmp_id0) - 1024) / sm->port_per_thread;
 	  else
 	    ti = sm->num_workers;
-	  int rv = clib_bihash_search_8_8 (&sm->per_thread_data[ti].out2in,
-					   &kv0, &value0);
+	  int rv = clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0);
 	  if (!rv)
 	    {
-	      si = value0.value;
+	      si = nat_value_get_session_index (&value0);
 	      s0 = pool_elt_at_index (sm->per_thread_data[ti].sessions, si);
 	      new_dst_addr0 = s0->in2out.addr.as_u32;
 	      vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
diff --git a/src/plugins/nat/nat_inlines.h b/src/plugins/nat/nat_inlines.h
index 3408e533f69..d53e2453607 100644
--- a/src/plugins/nat/nat_inlines.h
+++ b/src/plugins/nat/nat_inlines.h
@@ -63,11 +63,12 @@ init_nat_k (clib_bihash_kv_8_8_t * kv, ip4_address_t addr, u16 port,
 }
 
 always_inline void
-init_nat_kv (clib_bihash_kv_8_8_t * kv, ip4_address_t addr, u16 port,
-	     u32 fib_index, nat_protocol_t proto, u64 value)
+init_nat_kv (clib_bihash_kv_8_8_t *kv, ip4_address_t addr, u16 port,
+	     u32 fib_index, nat_protocol_t proto, u32 thread_index,
+	     u32 session_index)
 {
   init_nat_k (kv, addr, port, fib_index, proto);
-  kv->value = value;
+  kv->value = (u64) thread_index << 32 | session_index;
 }
 
 always_inline void
@@ -78,11 +79,12 @@ init_nat_i2o_k (clib_bihash_kv_8_8_t * kv, snat_session_t * s)
 }
 
 always_inline void
-init_nat_i2o_kv (clib_bihash_kv_8_8_t * kv, snat_session_t * s, u64 value)
+init_nat_i2o_kv (clib_bihash_kv_8_8_t *kv, snat_session_t *s, u32 thread_index,
+		 u32 session_index)
 {
   init_nat_k (kv, s->in2out.addr, s->in2out.port, s->in2out.fib_index,
 	      s->nat_proto);
-  kv->value = value;
+  kv->value = (u64) thread_index << 32 | session_index;
 }
 
 always_inline void
@@ -93,11 +95,24 @@ init_nat_o2i_k (clib_bihash_kv_8_8_t * kv, snat_session_t * s)
 }
 
 always_inline void
-init_nat_o2i_kv (clib_bihash_kv_8_8_t * kv, snat_session_t * s, u64 value)
+init_nat_o2i_kv (clib_bihash_kv_8_8_t *kv, snat_session_t *s, u32 thread_index,
+		 u32 session_index)
 {
   init_nat_k (kv, s->out2in.addr, s->out2in.port, s->out2in.fib_index,
 	      s->nat_proto);
-  kv->value = value;
+  kv->value = (u64) thread_index << 32 | session_index;
+}
+
+always_inline u32
+nat_value_get_thread_index (clib_bihash_kv_8_8_t *value)
+{
+  return value->value >> 32;
+}
+
+always_inline u32
+nat_value_get_session_index (clib_bihash_kv_8_8_t *value)
+{
+  return value->value & ~(u32) 0;
 }
 
 static inline uword