nat: refactor and split fo EI/ED features p.2

Patch n. 2 aimed at moving EI features out of
NAT44 plugin & split of EI/ED functions.

Type: refactor

Change-Id: Ida20c1c084449b146344b6c3d8442f49efb6f3fa
Signed-off-by: Filip Varga <fivarga@cisco.com>

1 files changed, 785 insertions, 2 deletions

diff --git a/src/plugins/nat/nat44-ei/nat44_ei.c b/src/plugins/nat/nat44-ei/nat44_ei.c
index f50ccb9ba1b..00aa8e1b65b 100644
--- a/src/plugins/nat/nat44-ei/nat44_ei.c
+++ b/src/plugins/nat/nat44-ei/nat44_ei.c
@@ -36,18 +36,156 @@
 #include <nat/nat44-ei/nat44_ei_inlines.h>
 #include <nat/nat44-ei/nat44_ei.h>
 
+nat44_ei_main_t nat44_ei_main;
+
+static void nat44_ei_db_free ();
+
+static void nat44_ei_db_init (u32 translations, u32 translation_buckets,
+			      u32 user_buckets);
+
 int
-nat44_ei_plugin_enable ()
+nat44_ei_plugin_enable (nat44_ei_config_t c)
 {
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  snat_main_t *sm = &snat_main;
+
+  clib_memset (nm, 0, sizeof (*nm));
+
+  if (!c.users)
+    c.users = 1024;
+
+  if (!c.sessions)
+    c.sessions = 10 * 1024;
+
+  nm->rconfig = c;
+
+  nm->translations = c.sessions;
+  nm->translation_buckets = nat_calc_bihash_buckets (c.sessions);
+  nm->user_buckets = nat_calc_bihash_buckets (c.users);
+
+  // OBSOLETE
+
+  sm->static_mapping_only = c.static_mapping_only;
+  sm->static_mapping_connection_tracking = c.connection_tracking;
+  sm->out2in_dpo = c.out2in_dpo;
+  sm->forwarding_enabled = 0;
+  sm->mss_clamping = 0;
+  sm->pat = (!c.static_mapping_only ||
+	     (c.static_mapping_only && c.connection_tracking));
+
+  sm->max_users_per_thread = c.users;
+  sm->max_translations_per_thread = c.sessions;
+  sm->translation_buckets = nat_calc_bihash_buckets (c.sessions);
+  sm->max_translations_per_user =
+    c.user_sessions ? c.user_sessions : sm->max_translations_per_thread;
+
+  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);
+
+  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->worker_in2out_cb = nat44_ei_get_in2out_worker_index;
+  sm->worker_out2in_cb = nat44_ei_get_out2in_worker_index;
+
+  sm->in2out_node_index = sm->ei_in2out_node_index;
+  sm->out2in_node_index = sm->ei_out2in_node_index;
+
+  sm->in2out_output_node_index = sm->ei_in2out_output_node_index;
+
+  if (sm->pat)
+    {
+      sm->icmp_match_in2out_cb = icmp_match_in2out_slow;
+      sm->icmp_match_out2in_cb = icmp_match_out2in_slow;
+    }
+  else
+    {
+      sm->icmp_match_in2out_cb = icmp_match_in2out_fast;
+      sm->icmp_match_out2in_cb = icmp_match_out2in_fast;
+    }
+
+  nat_reset_timeouts (&sm->timeouts);
+  nat44_ei_db_init (nm->translations, nm->translation_buckets,
+		    nm->user_buckets);
   nat44_ei_set_alloc_default ();
   nat_ha_enable ();
+
+  // TODO: function for reset counters
+  vlib_zero_simple_counter (&sm->total_users, 0);
+  vlib_zero_simple_counter (&sm->total_sessions, 0);
+  vlib_zero_simple_counter (&sm->user_limit_reached, 0);
+
+  sm->enabled = 1;
+
   return 0;
 }
 
-void
+int
 nat44_ei_plugin_disable ()
 {
+  nat44_ei_main_t *nm = &nat44_ei_main;
+  snat_main_t *sm = &snat_main;
+  snat_interface_t *i, *vec;
+  int error = 0;
+
+  // first unregister all nodes from interfaces
+  vec = vec_dup (sm->interfaces);
+  vec_foreach (i, vec)
+    {
+      if (nat_interface_is_inside (i))
+	error = snat_interface_add_del (i->sw_if_index, 1, 1);
+      if (nat_interface_is_outside (i))
+	error = snat_interface_add_del (i->sw_if_index, 0, 1);
+
+      if (error)
+	{
+	  nat_log_err ("error occurred while removing interface %u",
+		       i->sw_if_index);
+	}
+    }
+  vec_free (vec);
+  sm->interfaces = 0;
+
+  vec = vec_dup (sm->output_feature_interfaces);
+  vec_foreach (i, vec)
+    {
+      if (nat_interface_is_inside (i))
+	error = snat_interface_add_del_output_feature (i->sw_if_index, 1, 1);
+      if (nat_interface_is_outside (i))
+	error = snat_interface_add_del_output_feature (i->sw_if_index, 0, 1);
+
+      if (error)
+	{
+	  nat_log_err ("error occurred while removing interface %u",
+		       i->sw_if_index);
+	}
+    }
+  vec_free (vec);
+  sm->output_feature_interfaces = 0;
+
   nat_ha_disable ();
+  nat44_ei_db_free ();
+
+  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);
+
+  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 (&nm->rconfig, 0, sizeof (nm->rconfig));
+  clib_memset (&sm->rconfig, 0, sizeof (sm->rconfig));
+
+  return error;
 }
 
 void
@@ -525,6 +663,651 @@ nat44_ei_set_alloc_mape (u16 psid, u16 psid_offset, u16 psid_length)
   sm->psid_length = psid_length;
 }
 
+static void
+nat44_ei_add_static_mapping_when_resolved (ip4_address_t l_addr, u16 l_port,
+					   u16 e_port, nat_protocol_t proto,
+					   u32 sw_if_index, u32 vrf_id,
+					   int addr_only, int identity_nat,
+					   u8 *tag)
+{
+  snat_main_t *sm = &snat_main;
+  snat_static_map_resolve_t *rp;
+
+  vec_add2 (sm->to_resolve, rp, 1);
+  clib_memset (rp, 0, sizeof (*rp));
+
+  rp->l_addr.as_u32 = l_addr.as_u32;
+  rp->l_port = l_port;
+  rp->e_port = e_port;
+  rp->sw_if_index = sw_if_index;
+  rp->vrf_id = vrf_id;
+  rp->proto = proto;
+  rp->addr_only = addr_only;
+  rp->identity_nat = identity_nat;
+  rp->tag = vec_dup (tag);
+}
+
+int
+nat44_ei_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
+		      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_t *s;
+  clib_bihash_8_8_t *t;
+
+  if (sm->endpoint_dependent)
+    return VNET_API_ERROR_UNSUPPORTED;
+
+  ip.dst_address.as_u32 = ip.src_address.as_u32 = addr->as_u32;
+  if (sm->num_workers > 1)
+    tsm = vec_elt_at_index (sm->per_thread_data,
+			    sm->worker_in2out_cb (&ip, fib_index, 0));
+  else
+    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;
+  if (!clib_bihash_search_8_8 (t, &kv, &value))
+    {
+      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, 0);
+      nat44_delete_session (sm, s, tsm - sm->per_thread_data);
+      return 0;
+    }
+
+  return VNET_API_ERROR_NO_SUCH_ENTRY;
+}
+
+int
+nat44_ei_add_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
+				 u16 l_port, u16 e_port, nat_protocol_t proto,
+				 u32 sw_if_index, u32 vrf_id, u8 addr_only,
+				 u8 identity_nat, u8 *tag, u8 is_add)
+{
+  snat_main_t *sm = &snat_main;
+  snat_static_mapping_t *m = 0;
+  clib_bihash_kv_8_8_t kv, value;
+  snat_address_t *a = 0;
+  u32 fib_index = ~0;
+  snat_interface_t *interface;
+  snat_main_per_thread_data_t *tsm;
+  snat_user_key_t u_key;
+  snat_user_t *u;
+  dlist_elt_t *head, *elt;
+  u32 elt_index, head_index;
+  u32 ses_index;
+  u64 user_index;
+  snat_session_t *s;
+  snat_static_map_resolve_t *rp, *rp_match = 0;
+  nat44_lb_addr_port_t *local;
+  u32 find = ~0;
+  int i;
+
+  if (sw_if_index != ~0)
+    {
+      ip4_address_t *first_int_addr;
+
+      for (i = 0; i < vec_len (sm->to_resolve); i++)
+	{
+	  rp = sm->to_resolve + i;
+	  if (rp->sw_if_index != sw_if_index ||
+	      rp->l_addr.as_u32 != l_addr.as_u32 || rp->vrf_id != vrf_id ||
+	      rp->addr_only != addr_only)
+	    continue;
+
+	  if (!addr_only)
+	    {
+	      if ((rp->l_port != l_port && rp->e_port != e_port) ||
+		  rp->proto != proto)
+		continue;
+	    }
+
+	  rp_match = rp;
+	  break;
+	}
+
+      /* Might be already set... */
+      first_int_addr = ip4_interface_first_address (
+	sm->ip4_main, sw_if_index, 0 /* just want the address */);
+
+      if (is_add)
+	{
+	  if (rp_match)
+	    return VNET_API_ERROR_VALUE_EXIST;
+
+	  nat44_ei_add_static_mapping_when_resolved (
+	    l_addr, l_port, e_port, proto, sw_if_index, vrf_id, addr_only,
+	    identity_nat, tag);
+
+	  /* DHCP resolution required? */
+	  if (!first_int_addr)
+	    return 0;
+
+	  e_addr.as_u32 = first_int_addr->as_u32;
+	  /* Identity mapping? */
+	  if (l_addr.as_u32 == 0)
+	    l_addr.as_u32 = e_addr.as_u32;
+	}
+      else
+	{
+	  if (!rp_match)
+	    return VNET_API_ERROR_NO_SUCH_ENTRY;
+
+	  vec_del1 (sm->to_resolve, i);
+
+	  if (!first_int_addr)
+	    return 0;
+
+	  e_addr.as_u32 = first_int_addr->as_u32;
+	  /* Identity mapping? */
+	  if (l_addr.as_u32 == 0)
+	    l_addr.as_u32 = e_addr.as_u32;
+	}
+    }
+
+  init_nat_k (&kv, e_addr, addr_only ? 0 : e_port, 0, addr_only ? 0 : proto);
+  if (!clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+    m = pool_elt_at_index (sm->static_mappings, value.value);
+
+  if (is_add)
+    {
+      if (m)
+	{
+	  // identity mapping for second vrf
+	  if (is_identity_static_mapping (m))
+	    {
+	      pool_foreach (local, m->locals)
+		{
+		  if (local->vrf_id == vrf_id)
+		    return VNET_API_ERROR_VALUE_EXIST;
+		}
+	      pool_get (m->locals, local);
+	      local->vrf_id = vrf_id;
+	      local->fib_index = fib_table_find_or_create_and_lock (
+		FIB_PROTOCOL_IP4, vrf_id, sm->fib_src_low);
+	      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;
+	    }
+	  return VNET_API_ERROR_VALUE_EXIST;
+	}
+
+      /* Convert VRF id to FIB index */
+      if (vrf_id != ~0)
+	{
+	  fib_index = fib_table_find_or_create_and_lock (
+	    FIB_PROTOCOL_IP4, vrf_id, sm->fib_src_low);
+	}
+      /* If not specified use inside VRF id from NAT44 plugin config */
+      else
+	{
+	  fib_index = sm->inside_fib_index;
+	  vrf_id = sm->inside_vrf_id;
+	  fib_table_lock (fib_index, FIB_PROTOCOL_IP4, sm->fib_src_low);
+	}
+
+      if (!identity_nat)
+	{
+	  init_nat_k (&kv, l_addr, addr_only ? 0 : l_port, fib_index,
+		      addr_only ? 0 : proto);
+	  if (!clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv,
+				       &value))
+	    return VNET_API_ERROR_VALUE_EXIST;
+	}
+
+      /* Find external address in allocated addresses and reserve port for
+	 address and port pair mapping when dynamic translations enabled */
+      if (!(addr_only || sm->static_mapping_only))
+	{
+	  for (i = 0; i < vec_len (sm->addresses); i++)
+	    {
+	      if (sm->addresses[i].addr.as_u32 == e_addr.as_u32)
+		{
+		  a = sm->addresses + i;
+		  /* External port must be unused */
+		  switch (proto)
+		    {
+#define _(N, j, n, s)                                                         \
+  case NAT_PROTOCOL_##N:                                                      \
+    if (a->busy_##n##_port_refcounts[e_port])                                 \
+      return VNET_API_ERROR_INVALID_VALUE;                                    \
+    ++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_nat_protocol
+#undef _
+			default : nat_elog_info ("unknown protocol");
+		      return VNET_API_ERROR_INVALID_VALUE_2;
+		    }
+		  break;
+		}
+	    }
+	  /* External address must be allocated */
+	  if (!a && (l_addr.as_u32 != e_addr.as_u32))
+	    {
+	      if (sw_if_index != ~0)
+		{
+		  for (i = 0; i < vec_len (sm->to_resolve); i++)
+		    {
+		      rp = sm->to_resolve + i;
+		      if (rp->addr_only)
+			continue;
+		      if (rp->sw_if_index != sw_if_index &&
+			  rp->l_addr.as_u32 != l_addr.as_u32 &&
+			  rp->vrf_id != vrf_id && rp->l_port != l_port &&
+			  rp->e_port != e_port && rp->proto != proto)
+			continue;
+
+		      vec_del1 (sm->to_resolve, i);
+		      break;
+		    }
+		}
+	      return VNET_API_ERROR_NO_SUCH_ENTRY;
+	    }
+	}
+
+      pool_get (sm->static_mappings, m);
+      clib_memset (m, 0, sizeof (*m));
+      m->tag = vec_dup (tag);
+      m->local_addr = l_addr;
+      m->external_addr = e_addr;
+
+      if (addr_only)
+	m->flags |= NAT_STATIC_MAPPING_FLAG_ADDR_ONLY;
+      else
+	{
+	  m->local_port = l_port;
+	  m->external_port = e_port;
+	  m->proto = proto;
+	}
+
+      if (identity_nat)
+	{
+	  m->flags |= NAT_STATIC_MAPPING_FLAG_IDENTITY_NAT;
+	  pool_get (m->locals, local);
+	  local->vrf_id = vrf_id;
+	  local->fib_index = fib_index;
+	}
+      else
+	{
+	  m->vrf_id = vrf_id;
+	  m->fib_index = fib_index;
+	}
+
+      if (sm->num_workers > 1)
+	{
+	  ip4_header_t ip = {
+	    .src_address = m->local_addr,
+	  };
+	  vec_add1 (m->workers, sm->worker_in2out_cb (&ip, m->fib_index, 0));
+	  tsm = vec_elt_at_index (sm->per_thread_data, m->workers[0]);
+	}
+      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,
+		   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,
+		   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;
+	  u_key.fib_index = m->fib_index;
+	  kv.key = u_key.as_u64;
+	  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->nsessions)
+		{
+		  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 (snat_is_session_static (s))
+			continue;
+
+		      if (!addr_only && s->in2out.port != m->local_port)
+			continue;
+
+		      nat_free_session_data (sm, s, tsm - sm->per_thread_data,
+					     0);
+		      nat44_delete_session (sm, s, tsm - sm->per_thread_data);
+
+		      if (!addr_only)
+			break;
+		    }
+		}
+	    }
+	}
+    }
+  else
+    {
+      if (!m)
+	{
+	  if (sw_if_index != ~0)
+	    return 0;
+	  else
+	    return VNET_API_ERROR_NO_SUCH_ENTRY;
+	}
+
+      if (identity_nat)
+	{
+	  if (vrf_id == ~0)
+	    vrf_id = sm->inside_vrf_id;
+
+	  pool_foreach (local, m->locals)
+	    {
+	      if (local->vrf_id == vrf_id)
+		find = local - m->locals;
+	    }
+	  if (find == ~0)
+	    return VNET_API_ERROR_NO_SUCH_ENTRY;
+
+	  local = pool_elt_at_index (m->locals, find);
+	  fib_index = local->fib_index;
+	  pool_put (m->locals, local);
+	}
+      else
+	fib_index = m->fib_index;
+
+      /* Free external address port */
+      if (!(addr_only || sm->static_mapping_only))
+	{
+	  for (i = 0; i < vec_len (sm->addresses); i++)
+	    {
+	      if (sm->addresses[i].addr.as_u32 == e_addr.as_u32)
+		{
+		  a = sm->addresses + i;
+		  switch (proto)
+		    {
+#define _(N, j, n, s)                                                         \
+  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_nat_protocol
+#undef _
+			default : return VNET_API_ERROR_INVALID_VALUE_2;
+		    }
+		  break;
+		}
+	    }
+	}
+
+      if (sm->num_workers > 1)
+	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);
+
+      init_nat_k (&kv, m->local_addr, m->local_port, fib_index, m->proto);
+      clib_bihash_add_del_8_8 (&sm->static_mapping_by_local, &kv, 0);
+
+      /* Delete session(s) for static mapping if exist */
+      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;
+	  nat44_ei_static_mapping_del_sessions (sm, tsm, u_key, addr_only,
+						e_addr, e_port);
+	}
+
+      fib_table_unlock (fib_index, FIB_PROTOCOL_IP4, sm->fib_src_low);
+      if (pool_elts (m->locals))
+	return 0;
+
+      init_nat_k (&kv, m->external_addr, m->external_port, 0, m->proto);
+      clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 0);
+
+      vec_free (m->tag);
+      vec_free (m->workers);
+      /* Delete static mapping from pool */
+      pool_put (sm->static_mappings, m);
+    }
+
+  if (!addr_only || (l_addr.as_u32 == e_addr.as_u32))
+    return 0;
+
+  /* Add/delete external address to FIB */
+  pool_foreach (interface, sm->interfaces)
+    {
+      if (nat_interface_is_inside (interface) || sm->out2in_dpo)
+	continue;
+
+      snat_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index, is_add);
+      break;
+    }
+  pool_foreach (interface, sm->output_feature_interfaces)
+    {
+      if (nat_interface_is_inside (interface) || sm->out2in_dpo)
+	continue;
+
+      snat_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index, is_add);
+      break;
+    }
+  return 0;
+}
+
+int
+nat44_ei_static_mapping_match (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, u8 *is_identity_nat)
+{
+  snat_main_t *sm = &snat_main;
+  clib_bihash_kv_8_8_t kv, value;
+  snat_static_mapping_t *m;
+  u16 port;
+
+  if (by_external)
+    {
+      init_nat_k (&kv, match_addr, match_port, 0, match_protocol);
+      if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv,
+				  &value))
+	{
+	  /* Try address only mapping */
+	  init_nat_k (&kv, match_addr, 0, 0, 0);
+	  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv,
+				      &value))
+	    return 1;
+	}
+      m = pool_elt_at_index (sm->static_mappings, value.value);
+
+      *mapping_fib_index = m->fib_index;
+      *mapping_addr = m->local_addr;
+      port = m->local_port;
+    }
+  else
+    {
+      init_nat_k (&kv, match_addr, match_port, match_fib_index,
+		  match_protocol);
+      if (clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv, &value))
+	{
+	  /* Try address only mapping */
+	  init_nat_k (&kv, match_addr, 0, match_fib_index, 0);
+	  if (clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv,
+				      &value))
+	    return 1;
+	}
+      m = pool_elt_at_index (sm->static_mappings, value.value);
+
+      *mapping_fib_index = sm->outside_fib_index;
+      *mapping_addr = m->external_addr;
+      port = m->external_port;
+    }
+
+  /* Address only mapping doesn't change port */
+  if (is_addr_only_static_mapping (m))
+    *mapping_port = match_port;
+  else
+    *mapping_port = port;
+
+  if (PREDICT_FALSE (is_addr_only != 0))
+    *is_addr_only = is_addr_only_static_mapping (m);
+
+  if (PREDICT_FALSE (is_identity_nat != 0))
+    *is_identity_nat = is_identity_static_mapping (m);
+
+  return 0;
+}
+
+static void
+nat44_ei_worker_db_free (snat_main_per_thread_data_t *tsm)
+{
+  pool_free (tsm->list_pool);
+  pool_free (tsm->lru_pool);
+  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);
+}
+
+static void
+nat44_ei_worker_db_init (snat_main_per_thread_data_t *tsm, u32 translations,
+			 u32 translation_buckets, u32 user_buckets)
+{
+  dlist_elt_t *head;
+
+  pool_alloc (tsm->list_pool, translations);
+  pool_alloc (tsm->lru_pool, translations);
+  pool_alloc (tsm->sessions, translations);
+
+  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);
+  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);
+}
+
+static void
+nat44_ei_db_free ()
+{
+  snat_main_t *sm = &snat_main;
+  snat_main_per_thread_data_t *tsm;
+
+  pool_free (sm->static_mappings);
+  clib_bihash_free_8_8 (&sm->static_mapping_by_local);
+  clib_bihash_free_8_8 (&sm->static_mapping_by_external);
+
+  if (sm->pat)
+    {
+      vec_foreach (tsm, sm->per_thread_data)
+	{
+	  nat44_ei_worker_db_free (tsm);
+	}
+    }
+}
+
+static void
+nat44_ei_db_init (u32 translations, u32 translation_buckets, u32 user_buckets)
+{
+  snat_main_t *sm = &snat_main;
+  snat_main_per_thread_data_t *tsm;
+
+  u32 static_mapping_buckets = 1024;
+  u32 static_mapping_memory_size = 64 << 20;
+
+  clib_bihash_init_8_8 (&sm->static_mapping_by_local,
+			"static_mapping_by_local", static_mapping_buckets,
+			static_mapping_memory_size);
+  clib_bihash_init_8_8 (&sm->static_mapping_by_external,
+			"static_mapping_by_external", static_mapping_buckets,
+			static_mapping_memory_size);
+  clib_bihash_set_kvp_format_fn_8_8 (&sm->static_mapping_by_local,
+				     format_static_mapping_kvp);
+  clib_bihash_set_kvp_format_fn_8_8 (&sm->static_mapping_by_external,
+				     format_static_mapping_kvp);
+
+  if (sm->pat)
+    {
+      vec_foreach (tsm, sm->per_thread_data)
+	{
+	  nat44_ei_worker_db_init (tsm, translations, translation_buckets,
+				   user_buckets);
+	}
+    }
+}
+
+void
+nat44_ei_sessions_clear ()
+{
+  nat44_ei_main_t *nm = &nat44_ei_main;
+
+  snat_main_per_thread_data_t *tsm;
+  snat_main_t *sm = &snat_main;
+
+  if (sm->pat)
+    {
+      vec_foreach (tsm, sm->per_thread_data)
+	{
+	  nat44_ei_worker_db_free (tsm);
+	  nat44_ei_worker_db_init (tsm, nm->translations,
+				   nm->translation_buckets, nm->user_buckets);
+	}
+    }
+
+  // TODO: function for reset counters
+  vlib_zero_simple_counter (&sm->total_users, 0);
+  vlib_zero_simple_counter (&sm->total_sessions, 0);
+  vlib_zero_simple_counter (&sm->user_limit_reached, 0);
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *