nat: NAT44 ED improvements and fixes

Fixed FIB entry per interface, pool and
static mapping registrations in NAT control plane.
Improved FIB configuration handling in NAT -
added functions to generalize handling of FIB & NAT,
cleaned up interface callback functions. Changed "is_"
macros to inline functions for easier debugging.

Type: improvement

Change-Id: I68a17761a975dd819139ae94e52a8a85d3f27ffc
Signed-off-by: Filip Varga <fivarga@cisco.com>

1 files changed, 247 insertions, 296 deletions

diff --git a/src/plugins/nat/nat44-ed/nat44_ed.c b/src/plugins/nat/nat44-ed/nat44_ed.c
index b9dbe6ebeca..a11043682b9 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed.c
@@ -239,58 +239,76 @@ nat_free_session_data (snat_main_t * sm, snat_session_t * s, u32 thread_index,
       if (nat_ed_ses_o2i_flow_hash_add_del (sm, thread_index, s, 0))
 	nat_elog_warn (sm, "flow hash del failed");
 
-  if (is_fwd_bypass_session (s))
-    {
-      return;
-    }
+      if (na44_ed_is_fwd_bypass_session (s))
+	{
+	  return;
+	}
 
-      if (is_affinity_sessions (s))
-	nat_affinity_unlock (s->ext_host_addr, s->out2in.addr,
-			     s->nat_proto, s->out2in.port);
+      if (nat44_ed_is_affinity_session (s))
+	nat_affinity_unlock (s->ext_host_addr, s->out2in.addr, s->nat_proto,
+			     s->out2in.port);
 
       if (!is_ha)
 	nat_syslog_nat44_sdel (
 	  0, 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));
+	  nat44_ed_is_twice_nat_session (s));
 
-  if (snat_is_unk_proto_session (s))
-    return;
+      if (snat_is_unk_proto_session (s))
+	return;
 
-  if (!is_ha)
-    {
-      /* log NAT event */
-      nat_ipfix_logging_nat44_ses_delete (thread_index,
-					  s->in2out.addr.as_u32,
-					  s->out2in.addr.as_u32,
-					  s->nat_proto,
-					  s->in2out.port,
-					  s->out2in.port,
-					  s->in2out.fib_index);
-    }
+      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);
+	}
 
   /* Twice NAT address and port for external host */
-  if (is_twice_nat_session (s))
-    {
-      snat_free_outside_address_and_port (sm->twice_nat_addresses,
-					  thread_index,
-					  &s->ext_host_nat_addr,
-					  s->ext_host_nat_port, s->nat_proto);
-    }
+      if (nat44_ed_is_twice_nat_session (s))
+	{
+	  snat_free_outside_address_and_port (
+	    sm->twice_nat_addresses, thread_index, &s->ext_host_nat_addr,
+	    s->ext_host_nat_port, s->nat_proto);
+	}
 
-  if (snat_is_session_static (s))
-    return;
+      if (nat44_ed_is_session_static (s))
+	return;
 
-  snat_free_outside_address_and_port (sm->addresses, thread_index,
-				      &s->out2in.addr, s->out2in.port,
-				      s->nat_proto);
+      snat_free_outside_address_and_port (sm->addresses, thread_index,
+					  &s->out2in.addr, s->out2in.port,
+					  s->nat_proto);
 }
 
-void
-snat_add_del_addr_to_fib (ip4_address_t * addr, u8 p_len, u32 sw_if_index,
-			  int is_add)
+static int
+is_snat_address_used_in_static_mapping (snat_main_t *sm, ip4_address_t addr)
+{
+  snat_static_mapping_t *m;
+  pool_foreach (m, sm->static_mappings)
+    {
+      if (is_sm_addr_only (m->flags) || is_sm_out2in_only (m->flags) ||
+	  is_sm_identity_nat (m->flags))
+	{
+	  continue;
+	}
+      if (m->external_addr.as_u32 == addr.as_u32)
+	{
+	  return 1;
+	}
+    }
+  return 0;
+}
+
+static void
+nat44_ed_add_del_addr_to_fib (ip4_address_t *addr, u8 p_len, u32 sw_if_index,
+			      int is_add)
 {
+  // Add the external NAT address to the FIB as receive entries. This ensures
+  // that VPP will reply to ARP for this address and we don't need to enable
+  // proxy ARP on the outside interface.
+
   snat_main_t *sm = &snat_main;
   fib_prefix_t prefix = {
     .fp_len = p_len,
@@ -302,33 +320,68 @@ snat_add_del_addr_to_fib (ip4_address_t * addr, u8 p_len, u32 sw_if_index,
   u32 fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
 
   if (is_add)
-    fib_table_entry_update_one_path (fib_index,
-				     &prefix,
-				     sm->fib_src_low,
-				     (FIB_ENTRY_FLAG_CONNECTED |
-				      FIB_ENTRY_FLAG_LOCAL |
-				      FIB_ENTRY_FLAG_EXCLUSIVE),
-				     DPO_PROTO_IP4,
-				     NULL,
-				     sw_if_index,
-				     ~0, 1, NULL, FIB_ROUTE_PATH_FLAG_NONE);
+    {
+      fib_table_entry_update_one_path (fib_index, &prefix, sm->fib_src_low,
+				       (FIB_ENTRY_FLAG_CONNECTED |
+					FIB_ENTRY_FLAG_LOCAL |
+					FIB_ENTRY_FLAG_EXCLUSIVE),
+				       DPO_PROTO_IP4, NULL, sw_if_index, ~0, 1,
+				       NULL, FIB_ROUTE_PATH_FLAG_NONE);
+    }
   else
-    fib_table_entry_delete (fib_index, &prefix, sm->fib_src_low);
+    {
+      fib_table_entry_delete (fib_index, &prefix, sm->fib_src_low);
+    }
 }
 
-static int
-is_snat_address_used_in_static_mapping (snat_main_t *sm, ip4_address_t addr)
+static void
+nat44_ed_add_del_addr_to_fib_foreach_out_if (ip4_address_t *addr, u8 is_add)
+{
+  snat_main_t *sm = &snat_main;
+  snat_interface_t *i;
+
+  pool_foreach (i, sm->interfaces)
+    {
+      if (nat44_ed_is_interface_outside (i))
+	{
+	  nat44_ed_add_del_addr_to_fib (addr, 32, i->sw_if_index, is_add);
+	}
+    }
+  pool_foreach (i, sm->output_feature_interfaces)
+    {
+      if (nat44_ed_is_interface_outside (i))
+	{
+	  nat44_ed_add_del_addr_to_fib (addr, 32, i->sw_if_index, is_add);
+	}
+    }
+}
+
+static_always_inline void
+nat44_ed_add_del_addr_to_fib_foreach_addr (u32 sw_if_index, u8 is_add)
+{
+  snat_main_t *sm = &snat_main;
+  snat_address_t *ap;
+
+  vec_foreach (ap, sm->addresses)
+    {
+      nat44_ed_add_del_addr_to_fib (&ap->addr, 32, sw_if_index, is_add);
+    }
+}
+
+static_always_inline void
+nat44_ed_add_del_addr_to_fib_foreach_addr_only_sm (u32 sw_if_index, u8 is_add)
 {
+  snat_main_t *sm = &snat_main;
   snat_static_mapping_t *m;
+
   pool_foreach (m, sm->static_mappings)
     {
-      if (is_sm_addr_only (m->flags) || is_sm_out2in_only (m->flags) ||
-	  is_sm_identity_nat (m->flags))
-	continue;
-      if (m->external_addr.as_u32 == addr.as_u32)
-	return 1;
+      if (is_sm_addr_only (m->flags) && !is_sm_identity_nat (m->flags))
+	{
+	  nat44_ed_add_del_addr_to_fib (&m->external_addr, 32, sw_if_index,
+					is_add);
+	}
     }
-  return 0;
 }
 
 int
@@ -337,7 +390,6 @@ nat44_ed_add_address (ip4_address_t *addr, u32 vrf_id, u8 twice_nat)
   snat_main_t *sm = &snat_main;
   vlib_thread_main_t *tm = vlib_get_thread_main ();
   snat_address_t *ap, *addresses;
-  snat_interface_t *i;
 
   addresses = twice_nat ? sm->twice_nat_addresses : sm->addresses;
 
@@ -386,22 +438,9 @@ nat44_ed_add_address (ip4_address_t *addr, u32 vrf_id, u8 twice_nat)
 
     if (!twice_nat)
   {
-    pool_foreach (i, sm->interfaces)
-      {
-	if (!nat_interface_is_inside (i))
-	  {
-	    snat_add_del_addr_to_fib (addr, 32, i->sw_if_index, 1);
-	    break;
-	  }
-      }
-    pool_foreach (i, sm->output_feature_interfaces)
-      {
-	if (!nat_interface_is_inside (i))
-	  {
-	    snat_add_del_addr_to_fib (addr, 32, i->sw_if_index, 1);
-	    break;
-	  }
-      }
+    // if we don't have enabled interface we don't add address
+    // to fib
+    nat44_ed_add_del_addr_to_fib_foreach_out_if (addr, 1);
   }
   return 0;
 }
@@ -415,7 +454,6 @@ nat44_ed_del_address (ip4_address_t addr, u8 delete_sm, u8 twice_nat)
   u32 *ses_to_be_removed = 0, *ses_index;
   snat_main_per_thread_data_t *tsm;
   snat_static_mapping_t *m;
-  snat_interface_t *i;
   int j;
 
   addresses = twice_nat ? sm->twice_nat_addresses : sm->addresses;
@@ -492,23 +530,7 @@ nat44_ed_del_address (ip4_address_t addr, u8 delete_sm, u8 twice_nat)
     if (!twice_nat)
   {
     vec_del1 (sm->addresses, j);
-    // delete external address from FIB
-    pool_foreach (i, sm->interfaces)
-      {
-	if (!nat_interface_is_inside (i))
-	  {
-	    snat_add_del_addr_to_fib (&addr, 32, i->sw_if_index, 0);
-	    break;
-	  }
-      }
-    pool_foreach (i, sm->output_feature_interfaces)
-      {
-	if (!nat_interface_is_inside (i))
-	  {
-	    snat_add_del_addr_to_fib (&addr, 32, i->sw_if_index, 0);
-	    break;
-	  }
-      }
+    nat44_ed_add_del_addr_to_fib_foreach_out_if (&addr, 0);
   }
   else { vec_del1 (sm->twice_nat_addresses, j); }
   return 0;
@@ -554,9 +576,9 @@ nat_ed_static_mapping_del_sessions (snat_main_t * sm,
           continue;
       }
 
-    if (is_lb_session (s))
+    if (nat44_ed_is_lb_session (s))
       continue;
-    if (!snat_is_session_static (s))
+    if (!nat44_ed_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);
@@ -765,7 +787,6 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 {
   snat_main_t *sm = &snat_main;
   clib_bihash_kv_8_8_t kv, value;
-  snat_interface_t *interface;
   nat44_lb_addr_port_t *local;
   snat_static_mapping_t *m;
   u32 fib_index = ~0;
@@ -924,6 +945,12 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
     {
       m->vrf_id = vrf_id;
       m->fib_index = fib_index;
+
+      // not identity && addr only
+      if (is_sm_addr_only (flags))
+	{
+	  nat44_ed_add_del_addr_to_fib_foreach_out_if (&e_addr, 1);
+	}
     }
 
   if (!is_sm_out2in_only (flags))
@@ -949,27 +976,6 @@ nat44_ed_add_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
       vec_add1 (m->workers, worker_index);
     }
 
-  if (is_sm_identity_nat (flags) || !is_sm_addr_only (flags))
-    return 0;
-
-  pool_foreach (interface, sm->interfaces)
-    {
-      if (nat_interface_is_inside (interface))
-	continue;
-
-      snat_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index, 1);
-      break;
-    }
-
-  pool_foreach (interface, sm->output_feature_interfaces)
-    {
-      if (nat_interface_is_inside (interface))
-	continue;
-
-      snat_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index, 1);
-      break;
-    }
-
   return 0;
 }
 
@@ -982,7 +988,6 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
   snat_main_t *sm = &snat_main;
 
   clib_bihash_kv_8_8_t kv, value;
-  snat_interface_t *interface;
   nat44_lb_addr_port_t *local;
   snat_static_mapping_t *m;
   u32 fib_index = ~0;
@@ -1107,36 +1112,21 @@ nat44_ed_del_static_mapping (ip4_address_t l_addr, ip4_address_t e_addr,
 
   fib_table_unlock (fib_index, FIB_PROTOCOL_IP4, sm->fib_src_low);
 
-  if (pool_elts (m->locals))
-    return 0;
-
-  // fib_index 0
-  init_nat_k (&kv, e_addr, e_port, 0, proto);
-  clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 0);
-
-  vec_free (m->tag);
-  vec_free (m->workers);
-  pool_put (sm->static_mappings, m);
-
-  if (is_sm_identity_nat (flags) || !is_sm_addr_only (flags))
-    return 0;
-
-  pool_foreach (interface, sm->interfaces)
+  if (!pool_elts (m->locals))
     {
-      if (nat_interface_is_inside (interface))
-	continue;
+      // this is last record remove all required stuff
+      // fib_index 0
+      init_nat_k (&kv, e_addr, e_port, 0, proto);
+      clib_bihash_add_del_8_8 (&sm->static_mapping_by_external, &kv, 0);
 
-      snat_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index, 0);
-      break;
-    }
-
-  pool_foreach (interface, sm->output_feature_interfaces)
-    {
-      if (nat_interface_is_inside (interface))
-	continue;
+      vec_free (m->tag);
+      vec_free (m->workers);
+      pool_put (sm->static_mappings, m);
 
-      snat_add_del_addr_to_fib (&e_addr, 32, interface->sw_if_index, 0);
-      break;
+      if (is_sm_addr_only (flags) && !is_sm_identity_nat (flags))
+	{
+	  nat44_ed_add_del_addr_to_fib_foreach_out_if (&e_addr, 0);
+	}
     }
 
   return 0;
@@ -1165,20 +1155,28 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 
   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;
+    {
+      m = 0;
+    }
   else
-    m = pool_elt_at_index (sm->static_mappings, value.value);
+    {
+      m = pool_elt_at_index (sm->static_mappings, value.value);
+    }
 
   if (m)
-    return VNET_API_ERROR_VALUE_EXIST;
+    {
+      return VNET_API_ERROR_VALUE_EXIST;
+    }
 
   if (vec_len (locals) < 2)
-    return VNET_API_ERROR_INVALID_VALUE;
+    {
+      return VNET_API_ERROR_INVALID_VALUE;
+    }
 
-  /* Find external address in allocated addresses and reserve port for
-     address and port pair mapping when dynamic translations enabled */
   if (!(sm->static_mapping_only || is_sm_out2in_only (flags)))
     {
+      /* Find external address in allocated addresses and reserve port for
+	 address and port pair mapping when dynamic translations enabled */
       for (i = 0; i < vec_len (sm->addresses); i++)
 	{
 	  if (sm->addresses[i].addr.as_u32 == e_addr.as_u32)
@@ -1206,9 +1204,11 @@ nat44_ed_add_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 	      break;
 	    }
 	}
-      /* External address must be allocated */
+      // external address must be allocated
       if (!a)
-	return VNET_API_ERROR_NO_SUCH_ENTRY;
+	{
+	  return VNET_API_ERROR_NO_SUCH_ENTRY;
+	}
     }
 
   pool_get (sm->static_mappings, m);
@@ -1306,7 +1306,6 @@ nat44_ed_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
   if (!is_sm_lb (m->flags))
     return VNET_API_ERROR_INVALID_VALUE;
 
-  /* Free external address port */
   if (!(sm->static_mapping_only || is_sm_out2in_only (flags)))
     {
       for (i = 0; i < vec_len (sm->addresses); i++)
@@ -1371,7 +1370,7 @@ nat44_ed_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       /* Delete sessions */
       pool_foreach (s, tsm->sessions)
 	{
-	  if (!(is_lb_session (s)))
+	  if (!(nat44_ed_is_lb_session (s)))
 	    continue;
 
 	  if ((s->in2out.addr.as_u32 != local->addr.as_u32) ||
@@ -1422,10 +1421,14 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
     m = pool_elt_at_index (sm->static_mappings, value.value);
 
   if (!m)
-    return VNET_API_ERROR_NO_SUCH_ENTRY;
+    {
+      return VNET_API_ERROR_NO_SUCH_ENTRY;
+    }
 
   if (!is_sm_lb (m->flags))
-    return VNET_API_ERROR_INVALID_VALUE;
+    {
+      return VNET_API_ERROR_INVALID_VALUE;
+    }
 
   pool_foreach (local, m->locals)
    {
@@ -1440,7 +1443,9 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
   if (is_add)
     {
       if (match_local)
-	return VNET_API_ERROR_VALUE_EXIST;
+	{
+	  return VNET_API_ERROR_VALUE_EXIST;
+	}
 
       pool_get (m->locals, local);
       clib_memset (local, 0, sizeof (*local));
@@ -1492,15 +1497,15 @@ nat44_ed_add_del_lb_static_mapping_local (ip4_address_t e_addr, u16 e_port,
 
       /* Delete sessions */
       pool_foreach (s, tsm->sessions) {
-        if (!(is_lb_session (s)))
-          continue;
+	  if (!(nat44_ed_is_lb_session (s)))
+	    continue;
 
-        if ((s->in2out.addr.as_u32 != match_local->addr.as_u32) ||
-            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, 0);
-        nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
+	  nat_free_session_data (sm, s, tsm - sm->per_thread_data, 0);
+	  nat_ed_session_delete (sm, s, tsm - sm->per_thread_data, 1);
       }
 
       pool_put (m->locals, match_local);
@@ -1633,9 +1638,7 @@ nat44_ed_add_interface (u32 sw_if_index, u8 is_inside)
   snat_main_t *sm = &snat_main;
 
   nat_outside_fib_t *outside_fib;
-  snat_static_mapping_t *m;
   snat_interface_t *i;
-  snat_address_t *ap;
   u32 fib_index;
   int rv;
 
@@ -1654,8 +1657,8 @@ nat44_ed_add_interface (u32 sw_if_index, u8 is_inside)
   i = nat44_ed_get_interface (sm->interfaces, sw_if_index);
   if (i)
     {
-      if ((nat_interface_is_inside (i) && is_inside) ||
-	  (nat_interface_is_outside (i) && !is_inside))
+      if ((nat44_ed_is_interface_inside (i) && is_inside) ||
+	  (nat44_ed_is_interface_outside (i) && !is_inside))
 	{
 	  return 0;
 	}
@@ -1725,19 +1728,8 @@ nat44_ed_add_interface (u32 sw_if_index, u8 is_inside)
 	  outside_fib->refcount = 1;
 	}
 
-      vec_foreach (ap, sm->addresses)
-	{
-	  snat_add_del_addr_to_fib (&ap->addr, 32, sw_if_index, 1);
-	}
-      pool_foreach (m, sm->static_mappings)
-	{
-	  if (!(is_sm_addr_only (m->flags)) ||
-	      (m->local_addr.as_u32 == m->external_addr.as_u32))
-	    {
-	      continue;
-	    }
-	  snat_add_del_addr_to_fib (&m->external_addr, 32, sw_if_index, 1);
-	}
+      nat44_ed_add_del_addr_to_fib_foreach_addr (sw_if_index, 1);
+      nat44_ed_add_del_addr_to_fib_foreach_addr_only_sm (sw_if_index, 1);
     }
   else
     {
@@ -1754,9 +1746,7 @@ nat44_ed_del_interface (u32 sw_if_index, u8 is_inside)
   snat_main_t *sm = &snat_main;
 
   nat_outside_fib_t *outside_fib;
-  snat_static_mapping_t *m;
   snat_interface_t *i;
-  snat_address_t *ap;
   u32 fib_index;
   int rv;
 
@@ -1773,7 +1763,7 @@ nat44_ed_del_interface (u32 sw_if_index, u8 is_inside)
       return VNET_API_ERROR_NO_SUCH_ENTRY;
     }
 
-  if (nat_interface_is_inside (i) && nat_interface_is_outside (i))
+  if (nat44_ed_is_interface_inside (i) && nat44_ed_is_interface_outside (i))
     {
       if (sm->num_workers > 1)
 	{
@@ -1847,20 +1837,8 @@ nat44_ed_del_interface (u32 sw_if_index, u8 is_inside)
 	    }
 	}
 
-      vec_foreach (ap, sm->addresses)
-	{
-	  snat_add_del_addr_to_fib (&ap->addr, 32, sw_if_index, 0);
-	}
-
-      pool_foreach (m, sm->static_mappings)
-	{
-	  if (!(is_sm_addr_only (m->flags)) ||
-	      (m->local_addr.as_u32 == m->external_addr.as_u32))
-	    {
-	      continue;
-	    }
-	  snat_add_del_addr_to_fib (&m->external_addr, 32, sw_if_index, 0);
-	}
+      nat44_ed_add_del_addr_to_fib_foreach_addr (sw_if_index, 0);
+      nat44_ed_add_del_addr_to_fib_foreach_addr_only_sm (sw_if_index, 0);
     }
 
   return 0;
@@ -1872,9 +1850,7 @@ nat44_ed_add_output_interface (u32 sw_if_index)
   snat_main_t *sm = &snat_main;
 
   nat_outside_fib_t *outside_fib;
-  snat_static_mapping_t *m;
   snat_interface_t *i;
-  snat_address_t *ap;
   u32 fib_index;
   int rv;
 
@@ -1960,20 +1936,8 @@ nat44_ed_add_output_interface (u32 sw_if_index)
       outside_fib->refcount = 1;
     }
 
-  vec_foreach (ap, sm->addresses)
-    {
-      snat_add_del_addr_to_fib (&ap->addr, 32, sw_if_index, 1);
-    }
-
-  pool_foreach (m, sm->static_mappings)
-    {
-      if (!((is_sm_addr_only (m->flags))) ||
-	  (m->local_addr.as_u32 == m->external_addr.as_u32))
-	{
-	  continue;
-	}
-      snat_add_del_addr_to_fib (&m->external_addr, 32, sw_if_index, 1);
-    }
+  nat44_ed_add_del_addr_to_fib_foreach_addr (sw_if_index, 1);
+  nat44_ed_add_del_addr_to_fib_foreach_addr_only_sm (sw_if_index, 1);
 
   return 0;
 }
@@ -1984,9 +1948,7 @@ nat44_ed_del_output_interface (u32 sw_if_index)
   snat_main_t *sm = &snat_main;
 
   nat_outside_fib_t *outside_fib;
-  snat_static_mapping_t *m;
   snat_interface_t *i;
-  snat_address_t *ap;
   u32 fib_index;
   int rv;
 
@@ -2060,20 +2022,8 @@ nat44_ed_del_output_interface (u32 sw_if_index)
 	}
     }
 
-  vec_foreach (ap, sm->addresses)
-    {
-      snat_add_del_addr_to_fib (&ap->addr, 32, sw_if_index, 0);
-    }
-
-  pool_foreach (m, sm->static_mappings)
-    {
-      if (!((is_sm_addr_only (m->flags))) ||
-	  (m->local_addr.as_u32 == m->external_addr.as_u32))
-	{
-	  continue;
-	}
-      snat_add_del_addr_to_fib (&m->external_addr, 32, sw_if_index, 0);
-    }
+  nat44_ed_add_del_addr_to_fib_foreach_addr (sw_if_index, 0);
+  nat44_ed_add_del_addr_to_fib_foreach_addr_only_sm (sw_if_index, 0);
 
   return 0;
 }
@@ -2133,7 +2083,7 @@ nat44_ed_update_outside_fib_cb (ip4_main_t *im, uword opaque, u32 sw_if_index,
      {
       if (i->sw_if_index == sw_if_index)
         {
-          if (!(nat_interface_is_outside (i)))
+	  if (!(nat44_ed_is_interface_outside (i)))
 	    return;
           match = 1;
         }
@@ -2143,7 +2093,7 @@ nat44_ed_update_outside_fib_cb (ip4_main_t *im, uword opaque, u32 sw_if_index,
      {
       if (i->sw_if_index == sw_if_index)
         {
-          if (!(nat_interface_is_outside (i)))
+	  if (!(nat44_ed_is_interface_outside (i)))
 	    return;
           match = 1;
         }
@@ -2189,7 +2139,7 @@ static void nat44_ed_add_del_interface_address_cb (
   ip4_main_t *im, uword opaque, u32 sw_if_index, ip4_address_t *address,
   u32 address_length, u32 if_address_index, u32 is_delete);
 
-static void nat44_ed_add_del_sm_addr_only_cb (
+static void nat44_ed_add_del_static_mapping_addr_only_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);
 
@@ -2388,7 +2338,7 @@ nat_init (vlib_main_t * vm)
   /* callbacks to call when interface address changes. */
   cbi.function = nat44_ed_add_del_interface_address_cb;
   vec_add1 (sm->ip4_main->add_del_interface_address_callbacks, cbi);
-  cbi.function = nat44_ed_add_del_sm_addr_only_cb;
+  cbi.function = nat44_ed_add_del_static_mapping_addr_only_cb;
   vec_add1 (sm->ip4_main->add_del_interface_address_callbacks, cbi);
 
   /* callbacks to call when interface to table biding changes */
@@ -2515,11 +2465,11 @@ nat44_plugin_disable ()
   pool = pool_dup (sm->interfaces);
   pool_foreach (i, pool)
     {
-      if (nat_interface_is_inside (i))
+      if (nat44_ed_is_interface_inside (i))
 	{
 	  error = nat44_ed_del_interface (i->sw_if_index, 1);
 	}
-      if (nat_interface_is_outside (i))
+      if (nat44_ed_is_interface_outside (i))
 	{
 	  error = nat44_ed_del_interface (i->sw_if_index, 0);
 	}
@@ -2590,7 +2540,7 @@ nat44_ed_forwarding_enable_disable (u8 is_enable)
     {
       pool_foreach (s, tsm->sessions)
 	{
-	  if (is_fwd_bypass_session (s))
+	  if (na44_ed_is_fwd_bypass_session (s))
 	    {
 	      vec_add1 (ses_to_be_removed, s - tsm->sessions);
 	    }
@@ -3253,32 +3203,36 @@ nat44_ed_sessions_clear ()
 }
 
 static void
-nat44_ed_add_del_sm_addr_only_cb (ip4_main_t *im, uword opaque,
-				  u32 sw_if_index, ip4_address_t *address,
-				  u32 address_length, u32 if_address_index,
-				  u32 is_delete)
+nat44_ed_add_del_static_mapping_addr_only_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)
 {
   clib_bihash_kv_8_8_t kv, value;
   snat_static_map_resolve_t *rp;
   snat_main_t *sm = &snat_main;
   snat_static_mapping_t *m;
-  ip4_address_t l_addr;
-  int i, rv = 0;
+  int i, rv = 0, match = 0;
 
   if (!sm->enabled)
-    return;
+    {
+      return;
+    }
 
+  // find first addr_only resolve record by sw_if_index
   for (i = 0; i < vec_len (sm->to_resolve); i++)
     {
       rp = sm->to_resolve + i;
       if (rp->addr_only && rp->sw_if_index == sw_if_index)
 	{
-	  goto match;
+	  match = 1;
+	  break;
 	}
     }
-  return;
+  if (!match)
+    {
+      return;
+    }
 
-match:
   init_nat_k (&kv, *address, rp->addr_only ? 0 : rp->e_port,
 	      sm->outside_fib_index, rp->addr_only ? 0 : rp->proto);
 
@@ -3291,21 +3245,11 @@ match:
       m = pool_elt_at_index (sm->static_mappings, value.value);
     }
 
-  // Indetity mapping
-  if (rp->l_addr.as_u32 == 0)
-    {
-      l_addr.as_u32 = address[0].as_u32;
-    }
-  else
-    {
-      l_addr.as_u32 = rp->l_addr.as_u32;
-    }
-
   if (is_delete)
     {
       if (m)
 	{
-	  rv = nat44_ed_del_static_mapping (l_addr, address[0], rp->l_port,
+	  rv = nat44_ed_del_static_mapping (rp->l_addr, address[0], rp->l_port,
 					    rp->e_port, rp->proto, rp->vrf_id,
 					    ~0, rp->flags);
 	}
@@ -3315,10 +3259,10 @@ match:
       if (!m)
 	{
 	  rv = nat44_ed_add_static_mapping (
-	    l_addr, address[0], rp->l_port, rp->e_port, rp->proto, rp->vrf_id,
-	    ~0, rp->flags, rp->pool_addr, rp->tag);
+	    rp->l_addr, address[0], rp->l_port, rp->e_port, rp->proto,
+	    rp->vrf_id, ~0, rp->flags, rp->pool_addr, rp->tag);
 	}
-      // else don't trip over lease renewal, static config
+      // else: don't trip over lease renewal, static config
     }
   if (rv)
     {
@@ -3327,6 +3271,20 @@ match:
     }
 }
 
+static_always_inline int
+is_sw_if_index_reg_for_auto_resolve (u32 *sw_if_indices, u32 sw_if_index)
+{
+  u32 *i;
+  vec_foreach (i, sw_if_indices)
+    {
+      if (*i == sw_if_index)
+	{
+	  return 1;
+	}
+    }
+  return 0;
+}
+
 static void
 nat44_ed_add_del_interface_address_cb (ip4_main_t *im, uword opaque,
 				       u32 sw_if_index, ip4_address_t *address,
@@ -3335,61 +3293,55 @@ nat44_ed_add_del_interface_address_cb (ip4_main_t *im, uword opaque,
 {
   snat_main_t *sm = &snat_main;
   snat_static_map_resolve_t *rp;
-  ip4_address_t l_addr;
-  int i, j;
-  int rv;
-  u8 twice_nat = 0;
   snat_address_t *addresses = sm->addresses;
+  u8 twice_nat = 0;
+  int rv, i;
 
   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])
-	goto match;
-    }
-
-  for (i = 0; i < vec_len (sm->auto_add_sw_if_indices_twice_nat); i++)
+  if (!is_sw_if_index_reg_for_auto_resolve (sm->auto_add_sw_if_indices,
+					    sw_if_index))
     {
-      twice_nat = 1;
-      addresses = sm->twice_nat_addresses;
-      if (sw_if_index == sm->auto_add_sw_if_indices_twice_nat[i])
-	goto match;
+      if (!is_sw_if_index_reg_for_auto_resolve (
+	    sm->auto_add_sw_if_indices_twice_nat, sw_if_index))
+	{
+	  return;
+	}
+      else
+	{
+	  addresses = sm->twice_nat_addresses;
+	  twice_nat = 1;
+	}
     }
 
-  return;
-
-match:
   if (!is_delete)
     {
-      /* Don't trip over lease renewal, static config */
-      for (j = 0; j < vec_len (addresses); j++)
-	if (addresses[j].addr.as_u32 == address->as_u32)
-	  return;
+      // don't trip over lease renewal, static config
+      for (i = 0; i < vec_len (addresses); i++)
+	{
+	  if (addresses[i].addr.as_u32 == address->as_u32)
+	    {
+	      return;
+	    }
+	}
 
       (void) nat44_ed_add_address (address, ~0, twice_nat);
-      /* Scan static map resolution vector */
-      for (j = 0; j < vec_len (sm->to_resolve); j++)
+
+      // scan static mapping switch address resolution record vector
+      for (i = 0; i < vec_len (sm->to_resolve); i++)
 	{
-	  rp = sm->to_resolve + j;
+	  rp = sm->to_resolve + i;
 	  if (rp->addr_only)
-	    continue;
-	  /* On this interface? */
+	    {
+	      continue;
+	    }
 	  if (rp->sw_if_index == sw_if_index)
 	    {
-	      // TODO: remove if not needed (handled by function)
-	      /* Indetity mapping? */
-	      if (rp->l_addr.as_u32 == 0)
-		l_addr.as_u32 = address[0].as_u32;
-	      else
-		l_addr.as_u32 = rp->l_addr.as_u32;
-
-	      /* Add the static mapping */
 	      rv = nat44_ed_add_static_mapping (
-		l_addr, address[0], rp->l_port, rp->e_port, rp->proto,
+		rp->l_addr, address[0], rp->l_port, rp->e_port, rp->proto,
 		rp->vrf_id, ~0, rp->flags, rp->pool_addr, rp->tag);
 	      if (rv)
 		{
@@ -3398,7 +3350,6 @@ match:
 		}
 	    }
 	}
-      return;
     }
   else
     {