NAT44: endpoint dependent mode (VPP-1273)

To enable NAT plugin endpoint dependent mode add following to statrup config:
nat { endpoint-dependent }

Enable endpoint dependent filtering and mapping for all sessions.
Move some existing functionality such as service load balancing, twice nat,
out2in-only static mappings and unknown protocol dynamic translations, which
use endpoint dependent lookup hash tables before. Basically split to vanilla
NAT44 and extra features NAT44.

Change-Id: I3925eb5ddcc8f1ec4cf6af4e2a618a7ec7aa9735
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 1343 insertions, 571 deletions

diff --git a/src/plugins/nat/out2in.c b/src/plugins/nat/out2in.c
index 83e1426a413..80465b071d4 100755
--- a/src/plugins/nat/out2in.c
+++ b/src/plugins/nat/out2in.c
@@ -104,6 +104,8 @@ vlib_node_registration_t snat_out2in_fast_node;
 vlib_node_registration_t snat_out2in_worker_handoff_node;
 vlib_node_registration_t snat_det_out2in_node;
 vlib_node_registration_t nat44_out2in_reass_node;
+vlib_node_registration_t nat44_ed_out2in_node;
+vlib_node_registration_t nat44_ed_out2in_slowpath_node;
 
 #define foreach_snat_out2in_error                       \
 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")         \
@@ -135,7 +137,6 @@ typedef enum {
   SNAT_OUT2IN_NEXT_LOOKUP,
   SNAT_OUT2IN_NEXT_ICMP_ERROR,
   SNAT_OUT2IN_NEXT_REASS,
-  SNAT_OUT2IN_NEXT_IN2OUT,
   SNAT_OUT2IN_N_NEXT,
 } snat_out2in_next_t;
 
@@ -268,161 +269,6 @@ snat_out2in_error_t icmp_get_key(ip4_header_t *ip0,
   return -1; /* success */
 }
 
-static_always_inline int
-icmp_get_ed_key(ip4_header_t *ip0, nat_ed_ses_key_t *p_key0)
-{
-  icmp46_header_t *icmp0;
-  nat_ed_ses_key_t key0;
-  icmp_echo_header_t *echo0, *inner_echo0 = 0;
-  ip4_header_t *inner_ip0;
-  void *l4_header = 0;
-  icmp46_header_t *inner_icmp0;
-
-  icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
-  echo0 = (icmp_echo_header_t *)(icmp0+1);
-
-  if (!icmp_is_error_message (icmp0))
-    {
-      key0.proto = IP_PROTOCOL_ICMP;
-      key0.l_addr = ip0->dst_address;
-      key0.r_addr = ip0->src_address;
-      key0.l_port = key0.r_port = echo0->identifier;
-    }
-  else
-    {
-      inner_ip0 = (ip4_header_t *)(echo0+1);
-      l4_header = ip4_next_header (inner_ip0);
-      key0.proto = inner_ip0->protocol;
-      key0.l_addr = inner_ip0->src_address;
-      key0.r_addr = inner_ip0->dst_address;
-      switch (ip_proto_to_snat_proto (inner_ip0->protocol))
-        {
-        case SNAT_PROTOCOL_ICMP:
-          inner_icmp0 = (icmp46_header_t*)l4_header;
-          inner_echo0 = (icmp_echo_header_t *)(inner_icmp0+1);
-          key0.l_port = key0.r_port = inner_echo0->identifier;
-          break;
-        case SNAT_PROTOCOL_UDP:
-        case SNAT_PROTOCOL_TCP:
-          key0.l_port = ((tcp_udp_header_t*)l4_header)->src_port;
-          key0.r_port = ((tcp_udp_header_t*)l4_header)->dst_port;
-          break;
-        default:
-          return -1;
-        }
-    }
-  *p_key0 = key0;
-  return 0;
-}
-
-static int
-next_src_nat (snat_main_t * sm, ip4_header_t * ip, u32 proto, u16 src_port,
-              u32 thread_index)
-{
-  snat_session_key_t key;
-  clib_bihash_kv_8_8_t kv, value;
-
-  key.addr = ip->src_address;
-  key.port = src_port;
-  key.protocol = proto;
-  key.fib_index = sm->inside_fib_index;
-  kv.key = key.as_u64;
-
-  if (!clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].in2out, &kv,
-                               &value))
-    return 1;
-
-  return 0;
-}
-
-static void
-create_bypass_for_fwd(snat_main_t * sm, ip4_header_t * ip, u32 rx_fib_index,
-                      u32 thread_index)
-{
-  nat_ed_ses_key_t key;
-  clib_bihash_kv_16_8_t kv, value;
-  udp_header_t *udp;
-  snat_user_t *u;
-  snat_session_t *s = 0;
-  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
-  f64 now = vlib_time_now (sm->vlib_main);
-
-  if (ip->protocol == IP_PROTOCOL_ICMP)
-    {
-      if (icmp_get_ed_key (ip, &key))
-        return;
-    }
-  else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
-    {
-      udp = ip4_next_header(ip);
-      key.r_addr = ip->src_address;
-      key.l_addr = ip->dst_address;
-      key.proto = ip->protocol;
-      key.l_port = udp->dst_port;
-      key.r_port = udp->src_port;
-    }
-  else
-    {
-      key.r_addr = ip->src_address;
-      key.l_addr = ip->dst_address;
-      key.proto = ip->protocol;
-      key.l_port = key.r_port = 0;
-    }
-  key.fib_index = 0;
-  kv.key[0] = key.as_u64[0];
-  kv.key[1] = key.as_u64[1];
-
-  if (!clib_bihash_search_16_8 (&sm->in2out_ed, &kv, &value))
-    {
-      s = pool_elt_at_index (tsm->sessions, value.value);
-    }
-  else
-    {
-      if (PREDICT_FALSE (maximum_sessions_exceeded(sm, thread_index)))
-        return;
-
-      u = nat_user_get_or_create (sm, &ip->dst_address, sm->inside_fib_index, thread_index);
-      if (!u)
-        {
-          nat_log_warn ("create NAT user failed");
-          return;
-        }
-
-      s = nat_session_alloc_or_recycle (sm, u, thread_index);
-      if (!s)
-        {
-          nat_log_warn ("create NAT session failed");
-          return;
-        }
-
-      s->ext_host_addr = key.r_addr;
-      s->ext_host_port = key.r_port;
-      s->flags |= SNAT_SESSION_FLAG_FWD_BYPASS;
-      s->outside_address_index = ~0;
-      s->out2in.addr = key.l_addr;
-      s->out2in.port = key.l_port;
-      s->out2in.protocol = ip_proto_to_snat_proto (key.proto);
-      s->out2in.fib_index = 0;
-      s->in2out = s->out2in;
-      user_session_increment (sm, u, 0);
-
-      kv.value = s - tsm->sessions;
-      if (clib_bihash_add_del_16_8 (&sm->in2out_ed, &kv, 1))
-        nat_log_notice ("in2out_ed key add failed");
-    }
-
-  if (ip->protocol == IP_PROTOCOL_TCP)
-    {
-      tcp_header_t *tcp = ip4_next_header(ip);
-      if (nat44_set_tcp_session_state_o2i (sm, s, tcp, thread_index))
-        return;
-    }
-  /* Per-user LRU list maintenance */
-  nat44_session_update_lru (sm, s, thread_index);
-  /* Accounting */
-  nat44_session_update_counters (s, now, 0);
-}
-
 /**
  * Get address and port values to be used for ICMP packet translation
  * and create session if needed
@@ -495,12 +341,6 @@ u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
           else
             {
               dont_translate = 1;
-              if (next_src_nat(sm, ip0, key0.protocol, key0.port, thread_index))
-                {
-                  next0 = SNAT_OUT2IN_NEXT_IN2OUT;
-                  goto out;
-                }
-              create_bypass_for_fwd(sm, ip0, rx_fib_index0, thread_index);
               goto out;
             }
         }
@@ -534,34 +374,8 @@ u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
           goto out;
         }
 
-      if (PREDICT_FALSE (value0.value == ~0ULL))
-        {
-          nat_ed_ses_key_t key;
-          clib_bihash_kv_16_8_t s_kv, s_value;
-
-          key.as_u64[0] = 0;
-          key.as_u64[1] = 0;
-          if (icmp_get_ed_key (ip0, &key))
-            {
-              b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
-              next0 = SNAT_OUT2IN_NEXT_DROP;
-              goto out;
-            }
-          key.fib_index = rx_fib_index0;
-          s_kv.key[0] = key.as_u64[0];
-          s_kv.key[1] = key.as_u64[1];
-          if (!clib_bihash_search_16_8 (&sm->out2in_ed, &s_kv, &s_value))
-            s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-                                    s_value.value);
-          else
-           {
-              next0 = SNAT_OUT2IN_NEXT_DROP;
-              goto out;
-           }
-        }
-      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,
+                              value0.value);
     }
 
 out:
@@ -797,293 +611,36 @@ static inline u32 icmp_out2in_slow_path (snat_main_t *sm,
   return next0;
 }
 
-static snat_session_t *
-snat_out2in_unknown_proto (snat_main_t *sm,
-                           vlib_buffer_t * b,
-                           ip4_header_t * ip,
-                           u32 rx_fib_index,
-                           u32 thread_index,
-                           f64 now,
-                           vlib_main_t * vm,
-                           vlib_node_runtime_t * node)
+static int
+nat_out2in_sm_unknown_proto (snat_main_t *sm,
+                             vlib_buffer_t * b,
+                             ip4_header_t * ip,
+                             u32 rx_fib_index)
 {
   clib_bihash_kv_8_8_t kv, value;
-  clib_bihash_kv_16_8_t s_kv, s_value;
   snat_static_mapping_t *m;
   snat_session_key_t m_key;
   u32 old_addr, new_addr;
   ip_csum_t sum;
-  nat_ed_ses_key_t key;
-  snat_session_t * s;
-  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
-  snat_user_t *u;
-
-  old_addr = ip->dst_address.as_u32;
-
-  key.l_addr = ip->dst_address;
-  key.r_addr = ip->src_address;
-  key.fib_index = rx_fib_index;
-  key.proto = ip->protocol;
-  key.r_port = 0;
-  key.l_port = 0;
-  s_kv.key[0] = key.as_u64[0];
-  s_kv.key[1] = key.as_u64[1];
-
-  if (!clib_bihash_search_16_8 (&sm->out2in_ed, &s_kv, &s_value))
-    {
-      s = pool_elt_at_index (tsm->sessions, s_value.value);
-      new_addr = ip->dst_address.as_u32 = s->in2out.addr.as_u32;
-    }
-  else
-    {
-      if (PREDICT_FALSE (maximum_sessions_exceeded(sm, thread_index)))
-        {
-          b->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
-          nat_log_notice ("maximum sessions exceeded");
-          return 0;
-        }
-
-      m_key.addr = ip->dst_address;
-      m_key.port = 0;
-      m_key.protocol = 0;
-      m_key.fib_index = rx_fib_index;
-      kv.key = m_key.as_u64;
-      if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
-        {
-          b->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-          return 0;
-        }
-
-      m = pool_elt_at_index (sm->static_mappings, value.value);
-
-      new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
-
-      u = nat_user_get_or_create (sm, &ip->src_address, m->fib_index,
-                                  thread_index);
-      if (!u)
-        {
-          nat_log_warn ("create NAT user failed");
-          return 0;
-        }
-
-      /* Create a new session */
-      s = nat_session_alloc_or_recycle (sm, u, thread_index);
-      if (!s)
-        {
-          nat_log_warn ("create NAT session failed");
-          return 0;
-        }
-
-      s->ext_host_addr.as_u32 = ip->src_address.as_u32;
-      s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
-      s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
-      s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
-      s->outside_address_index = ~0;
-      s->out2in.addr.as_u32 = old_addr;
-      s->out2in.fib_index = rx_fib_index;
-      s->in2out.addr.as_u32 = new_addr;
-      s->in2out.fib_index = m->fib_index;
-      s->in2out.port = s->out2in.port = ip->protocol;
-      user_session_increment (sm, u, 1 /* static */);
-
-      /* Add to lookup tables */
-      s_kv.value = s - tsm->sessions;
-      if (clib_bihash_add_del_16_8 (&sm->out2in_ed, &s_kv, 1))
-        nat_log_notice ("out2in key add failed");
-
-      key.l_addr = ip->dst_address;
-      key.fib_index = m->fib_index;
-      s_kv.key[0] = key.as_u64[0];
-      s_kv.key[1] = key.as_u64[1];
-      if (clib_bihash_add_del_16_8 (&sm->in2out_ed, &s_kv, 1))
-        nat_log_notice ("in2out key add failed");
-   }
-
-  /* Update IP checksum */
-  sum = ip->checksum;
-  sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
-  ip->checksum = ip_csum_fold (sum);
-
-  vnet_buffer(b)->sw_if_index[VLIB_TX] = s->in2out.fib_index;
 
-  /* Accounting */
-  nat44_session_update_counters (s, now,
-                                 vlib_buffer_length_in_chain (vm, b));
-  /* Per-user LRU list maintenance */
-  nat44_session_update_lru (sm, s, thread_index);
+  m_key.addr = ip->dst_address;
+  m_key.port = 0;
+  m_key.protocol = 0;
+  m_key.fib_index = rx_fib_index;
+  kv.key = m_key.as_u64;
+  if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+    return 1;
 
-  return s;
-}
-
-static snat_session_t *
-snat_out2in_lb (snat_main_t *sm,
-                vlib_buffer_t * b,
-                ip4_header_t * ip,
-                u32 rx_fib_index,
-                u32 thread_index,
-                f64 now,
-                vlib_main_t * vm,
-                vlib_node_runtime_t * node)
-{
-  nat_ed_ses_key_t key;
-  clib_bihash_kv_16_8_t s_kv, s_value;
-  udp_header_t *udp = ip4_next_header (ip);
-  tcp_header_t *tcp = (tcp_header_t *) udp;
-  snat_session_t *s = 0;
-  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
-  snat_session_key_t e_key, l_key;
-  u32 old_addr, new_addr;
-  u32 proto = ip_proto_to_snat_proto (ip->protocol);
-  u16 new_port, old_port;
-  ip_csum_t sum;
-  snat_user_t *u;
-  u32 address_index;
-  snat_session_key_t eh_key;
-  twice_nat_type_t twice_nat;
-  u8 lb;
+  m = pool_elt_at_index (sm->static_mappings, value.value);
 
   old_addr = ip->dst_address.as_u32;
-
-  key.l_addr = ip->dst_address;
-  key.r_addr = ip->src_address;
-  key.fib_index = rx_fib_index;
-  key.proto = ip->protocol;
-  key.r_port = udp->src_port;
-  key.l_port = udp->dst_port;
-  s_kv.key[0] = key.as_u64[0];
-  s_kv.key[1] = key.as_u64[1];
-
-  if (!clib_bihash_search_16_8 (&sm->out2in_ed, &s_kv, &s_value))
-    {
-      s = pool_elt_at_index (tsm->sessions, s_value.value);
-    }
-  else
-    {
-      if (PREDICT_FALSE (maximum_sessions_exceeded(sm, thread_index)))
-        {
-          b->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
-          nat_log_notice ("maximum sessions exceeded");
-          return 0;
-        }
-
-      e_key.addr = ip->dst_address;
-      e_key.port = udp->dst_port;
-      e_key.protocol = proto;
-      e_key.fib_index = rx_fib_index;
-      if (snat_static_mapping_match(sm, e_key, &l_key, 1, 0, &twice_nat, &lb))
-        return 0;
-
-      u = nat_user_get_or_create (sm, &l_key.addr, l_key.fib_index,
-                                  thread_index);
-      if (!u)
-      {
-        nat_log_warn ("create NAT user failed");
-        return 0;
-      }
-
-      s = nat_session_alloc_or_recycle (sm, u, thread_index);
-      if (!s)
-        {
-          nat_log_warn ("create NAT session failed");
-          return 0;
-        }
-
-      s->ext_host_addr.as_u32 = ip->src_address.as_u32;
-      s->ext_host_port = udp->src_port;
-      s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
-      if (lb)
-        s->flags |= SNAT_SESSION_FLAG_LOAD_BALANCING;
-      s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
-      s->outside_address_index = ~0;
-      s->out2in = e_key;
-      s->in2out = l_key;
-      user_session_increment (sm, u, 1 /* static */);
-
-      /* Add to lookup tables */
-      s_kv.value = s - tsm->sessions;
-      if (clib_bihash_add_del_16_8 (&sm->out2in_ed, &s_kv, 1))
-        nat_log_notice ("out2in-ed key add failed");
-
-      if (twice_nat == TWICE_NAT ||
-          (twice_nat == TWICE_NAT_SELF &&
-           ip->src_address.as_u32 == l_key.addr.as_u32))
-        {
-          eh_key.protocol = proto;
-          if (snat_alloc_outside_address_and_port (sm->twice_nat_addresses, 0,
-                                                   thread_index, &eh_key,
-                                                   &address_index,
-                                                   sm->port_per_thread,
-                                                   sm->per_thread_data[thread_index].snat_thread_index))
-            {
-              b->error = node->errors[SNAT_OUT2IN_ERROR_OUT_OF_PORTS];
-              return 0;
-            }
-          key.r_addr.as_u32 = s->ext_host_nat_addr.as_u32 = eh_key.addr.as_u32;
-          key.r_port = s->ext_host_nat_port = eh_key.port;
-          s->flags |= SNAT_SESSION_FLAG_TWICE_NAT;
-        }
-      key.l_addr = l_key.addr;
-      key.fib_index = l_key.fib_index;
-      key.l_port = l_key.port;
-      s_kv.key[0] = key.as_u64[0];
-      s_kv.key[1] = key.as_u64[1];
-      if (clib_bihash_add_del_16_8 (&sm->in2out_ed, &s_kv, 1))
-        nat_log_notice ("in2out-ed key add failed");
-    }
-
-  new_addr = ip->dst_address.as_u32 = s->in2out.addr.as_u32;
-
-  /* Update IP checksum */
+  new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
   sum = ip->checksum;
   sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
-  if (is_twice_nat_session (s))
-    sum = ip_csum_update (sum, ip->src_address.as_u32,
-                          s->ext_host_nat_addr.as_u32, ip4_header_t,
-                          src_address);
   ip->checksum = ip_csum_fold (sum);
 
-  vnet_buffer(b)->sw_if_index[VLIB_TX] = s->in2out.fib_index;
-
-  if (PREDICT_TRUE(proto == SNAT_PROTOCOL_TCP))
-    {
-      old_port = tcp->dst_port;
-      tcp->dst_port = s->in2out.port;
-      new_port = tcp->dst_port;
-
-      sum = tcp->checksum;
-      sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
-      sum = ip_csum_update (sum, old_port, new_port, ip4_header_t, length);
-      if (is_twice_nat_session (s))
-        {
-          sum = ip_csum_update (sum, ip->src_address.as_u32,
-                                s->ext_host_nat_addr.as_u32, ip4_header_t,
-                                dst_address);
-          sum = ip_csum_update (sum, tcp->src_port, s->ext_host_nat_port,
-                                ip4_header_t, length);
-          tcp->src_port = s->ext_host_nat_port;
-          ip->src_address.as_u32 = s->ext_host_nat_addr.as_u32;
-        }
-      tcp->checksum = ip_csum_fold(sum);
-      if (nat44_set_tcp_session_state_o2i (sm, s, tcp, thread_index))
-        return s;
-    }
-  else
-    {
-      udp->dst_port = s->in2out.port;
-      if (is_twice_nat_session (s))
-        {
-          udp->src_port = s->ext_host_nat_port;
-          ip->src_address.as_u32 = s->ext_host_nat_addr.as_u32;
-        }
-      udp->checksum = 0;
-    }
-
-  /* Accounting */
-  nat44_session_update_counters (s, now, vlib_buffer_length_in_chain (vm, b));
-  /* Per-user LRU list maintenance */
-  nat44_session_update_lru (sm, s, thread_index);
-
-  return s;
+  vnet_buffer(b)->sw_if_index[VLIB_TX] = m->fib_index;
+  return 0;
 }
 
 static uword
@@ -1182,11 +739,14 @@ snat_out2in_node_fn (vlib_main_t * vm,
 
           if (PREDICT_FALSE (proto0 == ~0))
             {
-              s0 = snat_out2in_unknown_proto(sm, b0, ip0, rx_fib_index0,
-                                             thread_index, now, vm, node);
-	      if (!sm->forwarding_enabled)
-		if (!s0)
-		  next0 = SNAT_OUT2IN_NEXT_DROP;
+              if (nat_out2in_sm_unknown_proto(sm, b0, ip0, rx_fib_index0))
+                {
+                  if (!sm->forwarding_enabled)
+                    {
+                      b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+                      next0 = SNAT_OUT2IN_NEXT_DROP;
+                    }
+                }
               goto trace0;
             }
 
@@ -1237,16 +797,6 @@ snat_out2in_node_fn (vlib_main_t * vm,
                       next0 = SNAT_OUT2IN_NEXT_DROP;
                       goto trace0;
                     }
-                  else
-                    {
-                      if (next_src_nat(sm, ip0, proto0, udp0->src_port, thread_index))
-                        {
-                          next0 = SNAT_OUT2IN_NEXT_IN2OUT;
-                          goto trace0;
-                        }
-                      create_bypass_for_fwd(sm, ip0, rx_fib_index0, thread_index);
-                      goto trace0;
-                    }
                 }
 
               /* Create session initiated by host from external network */
@@ -1259,22 +809,8 @@ snat_out2in_node_fn (vlib_main_t * vm,
                 }
             }
           else
-            {
-              if (PREDICT_FALSE (value0.value == ~0ULL))
-                {
-                  s0 = snat_out2in_lb(sm, b0, ip0, rx_fib_index0, thread_index,
-                                      now, vm, node);
-                  if (!s0)
-                    next0 = SNAT_OUT2IN_NEXT_DROP;
-                  goto trace0;
-                }
-              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,
+                                    value0.value);
 
           old_addr0 = ip0->dst_address.as_u32;
           ip0->dst_address = s0->in2out.addr;
@@ -1355,11 +891,14 @@ snat_out2in_node_fn (vlib_main_t * vm,
 
           if (PREDICT_FALSE (proto1 == ~0))
             {
-              s1 = snat_out2in_unknown_proto(sm, b1, ip1, rx_fib_index1,
-                                             thread_index, now, vm, node);
-	      if (!sm->forwarding_enabled)
-		if (!s1)
-		  next1 = SNAT_OUT2IN_NEXT_DROP;
+              if (nat_out2in_sm_unknown_proto(sm, b1, ip1, rx_fib_index1))
+                {
+                  if (!sm->forwarding_enabled)
+                    {
+                      b1->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+                      next1 = SNAT_OUT2IN_NEXT_DROP;
+                    }
+                }
               goto trace1;
             }
 
@@ -1410,16 +949,6 @@ snat_out2in_node_fn (vlib_main_t * vm,
                       next1 = SNAT_OUT2IN_NEXT_DROP;
                       goto trace1;
                     }
-                  else
-                    {
-                      if (next_src_nat(sm, ip1, proto1, udp1->src_port, thread_index))
-                        {
-                          next1 = SNAT_OUT2IN_NEXT_IN2OUT;
-                          goto trace1;
-                        }
-                      create_bypass_for_fwd(sm, ip1, rx_fib_index1, thread_index);
-                      goto trace1;
-                    }
                 }
 
               /* Create session initiated by host from external network */
@@ -1432,22 +961,8 @@ snat_out2in_node_fn (vlib_main_t * vm,
                 }
             }
           else
-            {
-              if (PREDICT_FALSE (value1.value == ~0ULL))
-                {
-                  s1 = snat_out2in_lb(sm, b1, ip1, rx_fib_index1, thread_index,
-                                      now, vm, node);
-                  if (!s1)
-                    next1 = SNAT_OUT2IN_NEXT_DROP;
-                  goto trace1;
-                }
-              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,
+                                    value1.value);
 
           old_addr1 = ip1->dst_address.as_u32;
           ip1->dst_address = s1->in2out.addr;
@@ -1554,11 +1069,14 @@ snat_out2in_node_fn (vlib_main_t * vm,
 
           if (PREDICT_FALSE (proto0 == ~0))
             {
-              s0 = snat_out2in_unknown_proto(sm, b0, ip0, rx_fib_index0,
-                                             thread_index, now, vm, node);
-	      if (!sm->forwarding_enabled)
-		if (!s0)
-		  next0 = SNAT_OUT2IN_NEXT_DROP;
+              if (nat_out2in_sm_unknown_proto(sm, b0, ip0, rx_fib_index0))
+                {
+                  if (!sm->forwarding_enabled)
+                    {
+                      b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+                      next0 = SNAT_OUT2IN_NEXT_DROP;
+                    }
+                }
               goto trace00;
             }
 
@@ -1619,16 +1137,6 @@ snat_out2in_node_fn (vlib_main_t * vm,
                       next0 = SNAT_OUT2IN_NEXT_DROP;
                       goto trace00;
                     }
-                  else
-                    {
-                      if (next_src_nat(sm, ip0, proto0, udp0->src_port, thread_index))
-                        {
-                          next0 = SNAT_OUT2IN_NEXT_IN2OUT;
-                          goto trace00;
-                        }
-                      create_bypass_for_fwd(sm, ip0, rx_fib_index0, thread_index);
-                      goto trace00;
-                    }
                 }
 
               /* Create session initiated by host from external network */
@@ -1641,22 +1149,8 @@ snat_out2in_node_fn (vlib_main_t * vm,
                 }
             }
           else
-            {
-              if (PREDICT_FALSE (value0.value == ~0ULL))
-                {
-                  s0 = snat_out2in_lb(sm, b0, ip0, rx_fib_index0, thread_index,
-                                      now, vm, node);
-                  if (!s0)
-                    next0 = SNAT_OUT2IN_NEXT_DROP;
-                  goto trace00;
-                }
-              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,
+                                    value0.value);
 
           old_addr0 = ip0->dst_address.as_u32;
           ip0->dst_address = s0->in2out.addr;
@@ -1748,7 +1242,6 @@ VLIB_REGISTER_NODE (snat_out2in_node) = {
     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
-    [SNAT_OUT2IN_NEXT_IN2OUT] = "nat44-in2out",
   },
 };
 VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_node, snat_out2in_node_fn);
@@ -1869,18 +1362,8 @@ nat44_out2in_reass_node_fn (vlib_main_t * vm,
                         {
                           b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
                           next0 = SNAT_OUT2IN_NEXT_DROP;
-                          goto trace0;
-                        }
-                      else
-                        {
-                          if (next_src_nat(sm, ip0, proto0, udp0->src_port, thread_index))
-                            {
-                              next0 = SNAT_OUT2IN_NEXT_IN2OUT;
-                              goto trace0;
-                            }
-                          create_bypass_for_fwd(sm, ip0, rx_fib_index0, thread_index);
-                          goto trace0;
                         }
+                      goto trace0;
                     }
 
                   /* Create session initiated by host from external network */
@@ -2045,12 +1528,1303 @@ VLIB_REGISTER_NODE (nat44_out2in_reass_node) = {
     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
-    [SNAT_OUT2IN_NEXT_IN2OUT] = "nat44-in2out",
   },
 };
 VLIB_NODE_FUNCTION_MULTIARCH (nat44_out2in_reass_node,
                               nat44_out2in_reass_node_fn);
 
+/*******************************/
+/*** endpoint-dependent mode ***/
+/*******************************/
+typedef enum {
+  NAT44_ED_OUT2IN_NEXT_DROP,
+  NAT44_ED_OUT2IN_NEXT_LOOKUP,
+  NAT44_ED_OUT2IN_NEXT_ICMP_ERROR,
+  NAT44_ED_OUT2IN_NEXT_IN2OUT,
+  NAT44_ED_OUT2IN_NEXT_SLOW_PATH,
+  NAT44_ED_OUT2IN_N_NEXT,
+} nat44_ed_out2in_next_t;
+
+typedef struct {
+  u32 sw_if_index;
+  u32 next_index;
+  u32 session_index;
+  u32 is_slow_path;
+} nat44_ed_out2in_trace_t;
+
+static u8 *
+format_nat44_ed_out2in_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  nat44_ed_out2in_trace_t *t = va_arg (*args, nat44_ed_out2in_trace_t *);
+  char * tag;
+
+  tag = t->is_slow_path ? "NAT44_OUT2IN_SLOW_PATH" : "NAT44_OUT2IN_FAST_PATH";
+
+  s = format (s, "%s: sw_if_index %d, next index %d, session %d", tag,
+              t->sw_if_index, t->next_index, t->session_index);
+
+  return s;
+}
+
+static snat_session_t *
+create_session_for_static_mapping_ed (snat_main_t * sm,
+                                      vlib_buffer_t *b,
+                                      snat_session_key_t l_key,
+                                      snat_session_key_t e_key,
+                                      vlib_node_runtime_t * node,
+                                      u32 thread_index,
+                                      twice_nat_type_t twice_nat,
+                                      u8 is_lb)
+{
+  snat_session_t *s;
+  snat_user_t *u;
+  ip4_header_t *ip;
+  udp_header_t *udp;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  clib_bihash_kv_16_8_t kv;
+  snat_session_key_t eh_key;
+  u32 address_index;
+
+  if (PREDICT_FALSE (maximum_sessions_exceeded(sm, thread_index)))
+    {
+      b->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
+      nat_log_notice ("maximum sessions exceeded");
+      return 0;
+    }
+
+  u = nat_user_get_or_create (sm, &l_key.addr, l_key.fib_index, thread_index);
+  if (!u)
+    {
+      nat_log_warn ("create NAT user failed");
+      return 0;
+    }
+
+  s = nat_session_alloc_or_recycle (sm, u, thread_index);
+  if (!s)
+    {
+      nat_log_warn ("create NAT session failed");
+      return 0;
+    }
+
+  ip = vlib_buffer_get_current (b);
+  udp = ip4_next_header (ip);
+
+  s->ext_host_addr.as_u32 = ip->src_address.as_u32;
+  s->ext_host_port = e_key.protocol == SNAT_PROTOCOL_ICMP ? 0 : udp->src_port;
+  s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
+  if (is_lb)
+    s->flags |= SNAT_SESSION_FLAG_LOAD_BALANCING;
+  s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
+  s->outside_address_index = ~0;
+  s->out2in = e_key;
+  s->in2out = l_key;
+  s->in2out.protocol = s->out2in.protocol;
+  user_session_increment (sm, u, 1);
+
+  /* Add to lookup tables */
+  make_ed_kv (&kv, &e_key.addr, &s->ext_host_addr, ip->protocol,
+              e_key.fib_index, e_key.port, s->ext_host_port);
+  kv.value = s - tsm->sessions;
+  if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &kv, 1))
+    nat_log_notice ("out2in-ed key add failed");
+
+  if (twice_nat == TWICE_NAT || (twice_nat == TWICE_NAT_SELF &&
+      ip->src_address.as_u32 == l_key.addr.as_u32))
+    {
+      eh_key.protocol = e_key.protocol;
+      if (snat_alloc_outside_address_and_port (sm->twice_nat_addresses, 0,
+                                               thread_index, &eh_key,
+                                               &address_index,
+                                               sm->port_per_thread,
+                                               tsm->snat_thread_index))
+        {
+          b->error = node->errors[SNAT_OUT2IN_ERROR_OUT_OF_PORTS];
+          nat44_delete_session (sm, s, thread_index);
+          if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &kv, 0))
+            nat_log_notice ("out2in-ed key del failed");
+          return 0;
+        }
+      s->ext_host_nat_addr.as_u32 = eh_key.addr.as_u32;
+      s->ext_host_nat_port = eh_key.port;
+      s->flags |= SNAT_SESSION_FLAG_TWICE_NAT;
+      make_ed_kv (&kv, &l_key.addr, &s->ext_host_nat_addr, ip->protocol,
+                  l_key.fib_index, l_key.port, s->ext_host_nat_port);
+    }
+  else
+    {
+      make_ed_kv (&kv, &l_key.addr, &s->ext_host_addr, ip->protocol,
+                  l_key.fib_index, l_key.port, s->ext_host_port);
+    }
+  kv.value = s - tsm->sessions;
+  if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &kv, 1))
+    nat_log_notice ("in2out-ed key add failed");
+
+  return s;
+}
+
+static_always_inline int
+icmp_get_ed_key(ip4_header_t *ip0, nat_ed_ses_key_t *p_key0)
+{
+  icmp46_header_t *icmp0;
+  nat_ed_ses_key_t key0;
+  icmp_echo_header_t *echo0, *inner_echo0 = 0;
+  ip4_header_t *inner_ip0;
+  void *l4_header = 0;
+  icmp46_header_t *inner_icmp0;
+
+  icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
+  echo0 = (icmp_echo_header_t *)(icmp0+1);
+
+  if (!icmp_is_error_message (icmp0))
+    {
+      key0.proto = IP_PROTOCOL_ICMP;
+      key0.l_addr = ip0->dst_address;
+      key0.r_addr = ip0->src_address;
+      key0.l_port = echo0->identifier;
+      key0.r_port = 0;
+    }
+  else
+    {
+      inner_ip0 = (ip4_header_t *)(echo0+1);
+      l4_header = ip4_next_header (inner_ip0);
+      key0.proto = inner_ip0->protocol;
+      key0.l_addr = inner_ip0->src_address;
+      key0.r_addr = inner_ip0->dst_address;
+      switch (ip_proto_to_snat_proto (inner_ip0->protocol))
+        {
+        case SNAT_PROTOCOL_ICMP:
+          inner_icmp0 = (icmp46_header_t*)l4_header;
+          inner_echo0 = (icmp_echo_header_t *)(inner_icmp0+1);
+          key0.l_port = inner_echo0->identifier;
+          key0.r_port = 0;
+          break;
+        case SNAT_PROTOCOL_UDP:
+        case SNAT_PROTOCOL_TCP:
+          key0.l_port = ((tcp_udp_header_t*)l4_header)->src_port;
+          key0.r_port = ((tcp_udp_header_t*)l4_header)->dst_port;
+          break;
+        default:
+          return -1;
+        }
+    }
+  *p_key0 = key0;
+  return 0;
+}
+
+static int
+next_src_nat (snat_main_t * sm, ip4_header_t * ip, u8 proto, u16 src_port,
+              u16 dst_port, u32 thread_index)
+{
+  clib_bihash_kv_16_8_t kv, value;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+
+  make_ed_kv (&kv, &ip->src_address, &ip->dst_address, proto,
+              sm->inside_fib_index, src_port, dst_port);
+  if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
+    return 1;
+
+  return 0;
+}
+
+static void
+create_bypass_for_fwd(snat_main_t * sm, ip4_header_t * ip, u32 rx_fib_index,
+                      u32 thread_index)
+{
+  nat_ed_ses_key_t key;
+  clib_bihash_kv_16_8_t kv, value;
+  udp_header_t *udp;
+  snat_user_t *u;
+  snat_session_t *s = 0;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  f64 now = vlib_time_now (sm->vlib_main);
+
+  if (ip->protocol == IP_PROTOCOL_ICMP)
+    {
+      if (icmp_get_ed_key (ip, &key))
+        return;
+    }
+  else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
+    {
+      udp = ip4_next_header(ip);
+      key.r_addr = ip->src_address;
+      key.l_addr = ip->dst_address;
+      key.proto = ip->protocol;
+      key.l_port = udp->dst_port;
+      key.r_port = udp->src_port;
+    }
+  else
+    {
+      key.r_addr = ip->src_address;
+      key.l_addr = ip->dst_address;
+      key.proto = ip->protocol;
+      key.l_port = key.r_port = 0;
+    }
+  key.fib_index = 0;
+  kv.key[0] = key.as_u64[0];
+  kv.key[1] = key.as_u64[1];
+
+  if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
+    {
+      s = pool_elt_at_index (tsm->sessions, value.value);
+    }
+  else
+    {
+      if (PREDICT_FALSE (maximum_sessions_exceeded(sm, thread_index)))
+        return;
+
+      u = nat_user_get_or_create (sm, &ip->dst_address, sm->inside_fib_index,
+                                  thread_index);
+      if (!u)
+        {
+          nat_log_warn ("create NAT user failed");
+          return;
+        }
+
+      s = nat_session_alloc_or_recycle (sm, u, thread_index);
+      if (!s)
+        {
+          nat_log_warn ("create NAT session failed");
+          return;
+        }
+
+      s->ext_host_addr = key.r_addr;
+      s->ext_host_port = key.r_port;
+      s->flags |= SNAT_SESSION_FLAG_FWD_BYPASS;
+      s->outside_address_index = ~0;
+      s->out2in.addr = key.l_addr;
+      s->out2in.port = key.l_port;
+      s->out2in.protocol = ip_proto_to_snat_proto (key.proto);
+      s->out2in.fib_index = 0;
+      s->in2out = s->out2in;
+      user_session_increment (sm, u, 0);
+
+      kv.value = s - tsm->sessions;
+      if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &kv, 1))
+        nat_log_notice ("in2out_ed key add failed");
+    }
+
+  if (ip->protocol == IP_PROTOCOL_TCP)
+    {
+      tcp_header_t *tcp = ip4_next_header(ip);
+      if (nat44_set_tcp_session_state_o2i (sm, s, tcp, thread_index))
+        return;
+    }
+
+  /* Per-user LRU list maintenance */
+  nat44_session_update_lru (sm, s, thread_index);
+  /* Accounting */
+  nat44_session_update_counters (s, now, 0);
+}
+
+u32
+icmp_match_out2in_ed (snat_main_t * sm, vlib_node_runtime_t * node,
+                      u32 thread_index, vlib_buffer_t * b, ip4_header_t * ip,
+                      u8 * p_proto, snat_session_key_t * p_value,
+                      u8 * p_dont_translate, void * d, void * e)
+{
+  u32 next = ~0, sw_if_index, rx_fib_index;
+  icmp46_header_t *icmp;
+  nat_ed_ses_key_t key;
+  clib_bihash_kv_16_8_t kv, value;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  snat_session_t *s = 0;
+  u8 dont_translate = 0, is_addr_only;
+  snat_session_key_t e_key, l_key;
+
+  icmp = (icmp46_header_t *) ip4_next_header (ip);
+  sw_if_index = vnet_buffer(b)->sw_if_index[VLIB_RX];
+  rx_fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
+
+  if (icmp_get_ed_key (ip, &key))
+    {
+      b->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+      next = SNAT_OUT2IN_NEXT_DROP;
+      goto out;
+    }
+  key.fib_index = rx_fib_index;
+  kv.key[0] = key.as_u64[0];
+  kv.key[1] = key.as_u64[1];
+
+  if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv, &value))
+    {
+      /* Try to match static mapping */
+      e_key.addr = ip->dst_address;
+      e_key.port = key.l_port;
+      e_key.protocol = ip_proto_to_snat_proto (key.proto);
+      e_key.fib_index = rx_fib_index;
+      if (snat_static_mapping_match(sm, e_key, &l_key, 1, &is_addr_only, 0, 0))
+        {
+          if (!sm->forwarding_enabled)
+            {
+              /* Don't NAT packet aimed at the intfc address */
+              if (PREDICT_FALSE(is_interface_addr(sm, node, sw_if_index,
+                                                  ip->dst_address.as_u32)))
+                {
+                  dont_translate = 1;
+                  goto out;
+                }
+              b->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+              next = NAT44_ED_OUT2IN_NEXT_DROP;
+              goto out;
+            }
+          else
+            {
+              dont_translate = 1;
+              if (next_src_nat(sm, ip, key.proto, key.l_port, key.r_port, thread_index))
+                {
+                  next = NAT44_ED_OUT2IN_NEXT_IN2OUT;
+                  goto out;
+                }
+              create_bypass_for_fwd(sm, ip, rx_fib_index, thread_index);
+              goto out;
+            }
+        }
+
+      if (PREDICT_FALSE(icmp->type != ICMP4_echo_reply &&
+                        (icmp->type != ICMP4_echo_request || !is_addr_only)))
+        {
+          b->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
+          next = NAT44_ED_OUT2IN_NEXT_DROP;
+          goto out;
+        }
+
+      /* Create session initiated by host from external network */
+      s = create_session_for_static_mapping_ed(sm, b, l_key, e_key, node,
+                                               thread_index, 0, 0);
+
+      if (!s)
+        {
+          next = NAT44_ED_OUT2IN_NEXT_DROP;
+          goto out;
+        }
+    }
+  else
+    {
+      if (PREDICT_FALSE(icmp->type != ICMP4_echo_reply &&
+                        icmp->type != ICMP4_echo_request &&
+                        !icmp_is_error_message (icmp)))
+        {
+          b->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
+          next = SNAT_OUT2IN_NEXT_DROP;
+          goto out;
+        }
+
+      s = pool_elt_at_index (tsm->sessions, value.value);
+    }
+
+  *p_proto = ip_proto_to_snat_proto (key.proto);
+out:
+  if (s)
+    *p_value = s->in2out;
+  *p_dont_translate = dont_translate;
+  if (d)
+    *(snat_session_t**)d = s;
+  return next;
+}
+
+static snat_session_t *
+nat44_ed_out2in_unknown_proto (snat_main_t *sm,
+                               vlib_buffer_t * b,
+                               ip4_header_t * ip,
+                               u32 rx_fib_index,
+                               u32 thread_index,
+                               f64 now,
+                               vlib_main_t * vm,
+                               vlib_node_runtime_t * node)
+{
+  clib_bihash_kv_8_8_t kv, value;
+  clib_bihash_kv_16_8_t s_kv, s_value;
+  snat_static_mapping_t *m;
+  u32 old_addr, new_addr;
+  ip_csum_t sum;
+  snat_session_t * s;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  snat_user_t *u;
+
+  old_addr = ip->dst_address.as_u32;
+
+  make_ed_kv (&s_kv, &ip->dst_address, &ip->src_address, ip->protocol,
+              rx_fib_index, 0, 0);
+
+  if (!clib_bihash_search_16_8 (&tsm->out2in_ed, &s_kv, &s_value))
+    {
+      s = pool_elt_at_index (tsm->sessions, s_value.value);
+      new_addr = ip->dst_address.as_u32 = s->in2out.addr.as_u32;
+    }
+  else
+    {
+      if (PREDICT_FALSE (maximum_sessions_exceeded(sm, thread_index)))
+        {
+          b->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
+          nat_log_notice ("maximum sessions exceeded");
+          return 0;
+        }
+
+      make_sm_kv (&kv, &ip->dst_address, 0, rx_fib_index, 0);
+      if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+        {
+          b->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+          return 0;
+        }
+
+      m = pool_elt_at_index (sm->static_mappings, value.value);
+
+      new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
+
+      u = nat_user_get_or_create (sm, &ip->src_address, m->fib_index,
+                                  thread_index);
+      if (!u)
+        {
+          nat_log_warn ("create NAT user failed");
+          return 0;
+        }
+
+      /* Create a new session */
+      s = nat_session_alloc_or_recycle (sm, u, thread_index);
+      if (!s)
+        {
+          nat_log_warn ("create NAT session failed");
+          return 0;
+        }
+
+      s->ext_host_addr.as_u32 = ip->src_address.as_u32;
+      s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
+      s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
+      s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
+      s->outside_address_index = ~0;
+      s->out2in.addr.as_u32 = old_addr;
+      s->out2in.fib_index = rx_fib_index;
+      s->in2out.addr.as_u32 = new_addr;
+      s->in2out.fib_index = m->fib_index;
+      s->in2out.port = s->out2in.port = ip->protocol;
+      user_session_increment (sm, u, 1);
+
+      /* Add to lookup tables */
+      s_kv.value = s - tsm->sessions;
+      if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &s_kv, 1))
+        nat_log_notice ("out2in key add failed");
+
+      make_ed_kv (&s_kv, &ip->dst_address, &ip->src_address, ip->protocol,
+                  m->fib_index, 0, 0);
+      s_kv.value = s - tsm->sessions;
+      if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &s_kv, 1))
+        nat_log_notice ("in2out key add failed");
+   }
+
+  /* Update IP checksum */
+  sum = ip->checksum;
+  sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
+  ip->checksum = ip_csum_fold (sum);
+
+  vnet_buffer(b)->sw_if_index[VLIB_TX] = s->in2out.fib_index;
+
+  /* Accounting */
+  nat44_session_update_counters (s, now,
+                                 vlib_buffer_length_in_chain (vm, b));
+  /* Per-user LRU list maintenance */
+  nat44_session_update_lru (sm, s, thread_index);
+
+  return s;
+}
+
+static inline uword
+nat44_ed_out2in_node_fn_inline (vlib_main_t * vm,
+                                vlib_node_runtime_t * node,
+                                vlib_frame_t * frame, int is_slow_path)
+{
+  u32 n_left_from, *from, *to_next, pkts_processed = 0, stats_node_index;
+  nat44_ed_out2in_next_t next_index;
+  snat_main_t *sm = &snat_main;
+  f64 now = vlib_time_now (vm);
+  u32 thread_index = vlib_get_thread_index ();
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+
+  stats_node_index = is_slow_path ? nat44_ed_out2in_slowpath_node.index :
+    nat44_ed_out2in_node.index;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from >= 4 && n_left_to_next >= 2)
+	{
+          u32 bi0, bi1;
+	  vlib_buffer_t *b0, *b1;
+          u32 next0, sw_if_index0, rx_fib_index0, proto0, old_addr0, new_addr0;
+          u32 next1, sw_if_index1, rx_fib_index1, proto1, old_addr1, new_addr1;
+          u16 old_port0, new_port0, old_port1, new_port1;
+          ip4_header_t *ip0, *ip1;
+          udp_header_t *udp0, *udp1;
+          tcp_header_t *tcp0, *tcp1;
+          icmp46_header_t *icmp0, *icmp1;
+          snat_session_t *s0 = 0, *s1 = 0;
+          clib_bihash_kv_16_8_t kv0, value0, kv1, value1;
+          ip_csum_t sum0, sum1;
+          snat_session_key_t e_key0, l_key0, e_key1, l_key1;
+          u8 is_lb0, is_lb1;
+          twice_nat_type_t twice_nat0, twice_nat1;
+
+	  /* Prefetch next iteration. */
+	  {
+	    vlib_buffer_t * p2, * p3;
+
+	    p2 = vlib_get_buffer (vm, from[2]);
+	    p3 = vlib_get_buffer (vm, from[3]);
+
+	    vlib_prefetch_buffer_header (p2, LOAD);
+	    vlib_prefetch_buffer_header (p3, LOAD);
+
+	    CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
+	    CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
+	  }
+
+          /* speculatively enqueue b0 and b1 to the current next frame */
+	  to_next[0] = bi0 = from[0];
+	  to_next[1] = bi1 = from[1];
+	  from += 2;
+	  to_next += 2;
+	  n_left_from -= 2;
+	  n_left_to_next -= 2;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b1 = vlib_get_buffer (vm, bi1);
+
+          next0 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
+          vnet_buffer (b0)->snat.flags = 0;
+          ip0 = vlib_buffer_get_current (b0);
+
+          sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_RX];
+	  rx_fib_index0 = fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
+                                                               sw_if_index0);
+
+          if (PREDICT_FALSE(ip0->ttl == 1))
+            {
+              vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+              icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
+                                           ICMP4_time_exceeded_ttl_exceeded_in_transit,
+                                           0);
+              next0 = NAT44_ED_OUT2IN_NEXT_ICMP_ERROR;
+              goto trace00;
+            }
+
+          udp0 = ip4_next_header (ip0);
+          tcp0 = (tcp_header_t *) udp0;
+          icmp0 = (icmp46_header_t *) udp0;
+          proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+          if (is_slow_path)
+            {
+              if (PREDICT_FALSE (proto0 == ~0))
+                {
+                  s0 = nat44_ed_out2in_unknown_proto(sm, b0, ip0, rx_fib_index0,
+                                                     thread_index, now, vm, node);
+                  if (!sm->forwarding_enabled)
+                    {
+                      if (!s0)
+                        next0 = NAT44_ED_OUT2IN_NEXT_DROP;
+                      goto trace00;
+                    }
+                }
+
+              if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
+                {
+                  next0 = icmp_out2in_slow_path
+                    (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
+                     next0, now, thread_index, &s0);
+                  goto trace00;
+                }
+            }
+          else
+            {
+              if (PREDICT_FALSE (proto0 == ~0 || proto0 == SNAT_PROTOCOL_ICMP))
+                {
+                  next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
+                  goto trace00;
+                }
+
+              if (ip4_is_fragment (ip0))
+                {
+                  b0->error = node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT];
+                  next0 = NAT44_ED_OUT2IN_NEXT_DROP;
+                  goto trace00;
+                }
+            }
+
+          make_ed_kv (&kv0, &ip0->dst_address, &ip0->src_address, ip0->protocol,
+                      rx_fib_index0, udp0->dst_port, udp0->src_port);
+
+          if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv0, &value0))
+            {
+              if (is_slow_path)
+                {
+                  /* Try to match static mapping by external address and port,
+                     destination address and port in packet */
+                  e_key0.addr = ip0->dst_address;
+                  e_key0.port = udp0->dst_port;
+                  e_key0.protocol = proto0;
+                  e_key0.fib_index = rx_fib_index0;
+                  if (snat_static_mapping_match(sm, e_key0, &l_key0, 1, 0,
+                      &twice_nat0, &is_lb0))
+                    {
+                      /*
+                       * Send DHCP packets to the ipv4 stack, or we won't
+                       * be able to use dhcp client on the outside interface
+                       */
+                      if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
+                          && (udp0->dst_port ==
+                          clib_host_to_net_u16(UDP_DST_PORT_dhcp_to_client))))
+                        {
+                          vnet_feature_next
+                            (vnet_buffer (b0)->sw_if_index[VLIB_RX], &next0, b0);
+                          goto trace00;
+                        }
+
+                      if (!sm->forwarding_enabled)
+                        {
+                          b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+                          next0 = NAT44_ED_OUT2IN_NEXT_DROP;
+                        }
+                      else
+                        {
+                          if (next_src_nat(sm, ip0, ip0->protocol,
+                                           udp0->src_port, udp0->dst_port,
+                                           thread_index))
+                            {
+                              next0 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
+                              goto trace00;
+                            }
+                          create_bypass_for_fwd(sm, ip0, rx_fib_index0,
+                                                thread_index);
+                        }
+                      goto trace00;
+                    }
+
+                  /* Create session initiated by host from external network */
+                  s0 = create_session_for_static_mapping_ed(sm, b0, l_key0,
+                                                            e_key0, node,
+                                                            thread_index,
+                                                            twice_nat0, is_lb0);
+
+                  if (!s0)
+                    {
+                      next0 = NAT44_ED_OUT2IN_NEXT_DROP;
+                      goto trace00;
+                    }
+                }
+              else
+                {
+                  next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
+                  goto trace00;
+                }
+            }
+          else
+            {
+              s0 = pool_elt_at_index (tsm->sessions, value0.value);
+            }
+
+          old_addr0 = ip0->dst_address.as_u32;
+          new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
+          vnet_buffer(b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+
+          sum0 = ip0->checksum;
+          sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                                 dst_address);
+          if (PREDICT_FALSE (is_twice_nat_session (s0)))
+            sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
+                                   s0->ext_host_nat_addr.as_u32, ip4_header_t,
+                                   src_address);
+          ip0->checksum = ip_csum_fold (sum0);
+
+          if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
+            {
+              old_port0 = tcp0->dst_port;
+              new_port0 = tcp0->dst_port = s0->in2out.port;
+
+              sum0 = tcp0->checksum;
+              sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                                     dst_address);
+              sum0 = ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
+                                     length);
+              if (is_twice_nat_session (s0))
+                {
+                  sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
+                                         s0->ext_host_nat_addr.as_u32,
+                                         ip4_header_t, dst_address);
+                  sum0 = ip_csum_update (sum0, tcp0->src_port,
+                                         s0->ext_host_nat_port, ip4_header_t,
+                                         length);
+                  tcp0->src_port = s0->ext_host_nat_port;
+                  ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
+                }
+              tcp0->checksum = ip_csum_fold(sum0);
+              if (nat44_set_tcp_session_state_o2i (sm, s0, tcp0, thread_index))
+                goto trace00;
+            }
+          else
+            {
+              udp0->dst_port = s0->in2out.port;
+              if (is_twice_nat_session (s0))
+                {
+                  udp0->src_port = s0->ext_host_nat_port;
+                  ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
+                }
+              udp0->checksum = 0;
+            }
+
+          /* Accounting */
+          nat44_session_update_counters (s0, now,
+                                         vlib_buffer_length_in_chain (vm, b0));
+          /* Per-user LRU list maintenance */
+          nat44_session_update_lru (sm, s0, thread_index);
+
+        trace00:
+          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)
+                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+            {
+              nat44_ed_out2in_trace_t *t =
+                vlib_add_trace (vm, node, b0, sizeof (*t));
+              t->is_slow_path = is_slow_path;
+              t->sw_if_index = sw_if_index0;
+              t->next_index = next0;
+              t->session_index = ~0;
+              if (s0)
+                t->session_index = s0 - tsm->sessions;
+            }
+
+          pkts_processed += next0 != NAT44_ED_OUT2IN_NEXT_DROP;
+
+          next1 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
+          vnet_buffer (b1)->snat.flags = 0;
+          ip1 = vlib_buffer_get_current (b1);
+
+          sw_if_index1 = vnet_buffer(b1)->sw_if_index[VLIB_RX];
+	  rx_fib_index1 = fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
+                                                               sw_if_index1);
+
+          if (PREDICT_FALSE(ip1->ttl == 1))
+            {
+              vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+              icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
+                                           ICMP4_time_exceeded_ttl_exceeded_in_transit,
+                                           0);
+              next1 = NAT44_ED_OUT2IN_NEXT_ICMP_ERROR;
+              goto trace01;
+            }
+
+          udp1 = ip4_next_header (ip1);
+          tcp1 = (tcp_header_t *) udp1;
+          icmp1 = (icmp46_header_t *) udp1;
+          proto1 = ip_proto_to_snat_proto (ip1->protocol);
+
+          if (is_slow_path)
+            {
+              if (PREDICT_FALSE (proto1 == ~0))
+                {
+                  s1 = nat44_ed_out2in_unknown_proto(sm, b1, ip1, rx_fib_index1,
+                                                     thread_index, now, vm, node);
+                  if (!sm->forwarding_enabled)
+                    {
+                      if (!s1)
+                        next1 = NAT44_ED_OUT2IN_NEXT_DROP;
+                      goto trace01;
+                    }
+                }
+
+              if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
+                {
+                  next1 = icmp_out2in_slow_path
+                    (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
+                     next1, now, thread_index, &s1);
+                  goto trace01;
+                }
+            }
+          else
+            {
+              if (PREDICT_FALSE (proto1 == ~0 || proto1 == SNAT_PROTOCOL_ICMP))
+                {
+                  next1 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
+                  goto trace01;
+                }
+
+              if (ip4_is_fragment (ip1))
+                {
+                  b1->error = node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT];
+                  next1 = NAT44_ED_OUT2IN_NEXT_DROP;
+                  goto trace01;
+                }
+            }
+
+          make_ed_kv (&kv1, &ip1->dst_address, &ip1->src_address, ip1->protocol,
+                      rx_fib_index1, udp1->dst_port, udp1->src_port);
+
+          if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv1, &value1))
+            {
+              if (is_slow_path)
+                {
+                  /* Try to match static mapping by external address and port,
+                     destination address and port in packet */
+                  e_key1.addr = ip1->dst_address;
+                  e_key1.port = udp1->dst_port;
+                  e_key1.protocol = proto1;
+                  e_key1.fib_index = rx_fib_index1;
+                  if (snat_static_mapping_match(sm, e_key1, &l_key1, 1, 0,
+                      &twice_nat1, &is_lb1))
+                    {
+                      /*
+                       * Send DHCP packets to the ipv4 stack, or we won't
+                       * be able to use dhcp client on the outside interface
+                       */
+                      if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_UDP
+                          && (udp1->dst_port ==
+                          clib_host_to_net_u16(UDP_DST_PORT_dhcp_to_client))))
+                        {
+                          vnet_feature_next
+                            (vnet_buffer (b1)->sw_if_index[VLIB_RX], &next1, b1);
+                          goto trace01;
+                        }
+
+                      if (!sm->forwarding_enabled)
+                        {
+                          b1->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+                          next1 = NAT44_ED_OUT2IN_NEXT_DROP;
+                        }
+                      else
+                        {
+                          if (next_src_nat(sm, ip1, ip1->protocol,
+                                           udp1->src_port, udp1->dst_port,
+                                           thread_index))
+                            {
+                              next1 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
+                              goto trace01;
+                            }
+                          create_bypass_for_fwd(sm, ip1, rx_fib_index1,
+                                                thread_index);
+                        }
+                      goto trace01;
+                    }
+
+                  /* Create session initiated by host from external network */
+                  s1 = create_session_for_static_mapping_ed(sm, b1, l_key1,
+                                                            e_key1, node,
+                                                            thread_index,
+                                                            twice_nat1, is_lb1);
+
+                  if (!s1)
+                    {
+                      next1 = NAT44_ED_OUT2IN_NEXT_DROP;
+                      goto trace01;
+                    }
+                }
+              else
+                {
+                  next1 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
+                  goto trace01;
+                }
+            }
+          else
+            {
+              s1 = pool_elt_at_index (tsm->sessions, value1.value);
+            }
+
+          old_addr1 = ip1->dst_address.as_u32;
+          new_addr1 = ip1->dst_address.as_u32 = s1->in2out.addr.as_u32;
+          vnet_buffer(b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
+
+          sum1 = ip1->checksum;
+          sum1 = ip_csum_update (sum1, old_addr1, new_addr1, ip4_header_t,
+                                 dst_address);
+          if (PREDICT_FALSE (is_twice_nat_session (s1)))
+            sum1 = ip_csum_update (sum1, ip1->src_address.as_u32,
+                                   s1->ext_host_nat_addr.as_u32, ip4_header_t,
+                                   src_address);
+          ip1->checksum = ip_csum_fold (sum1);
+
+          if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
+            {
+              old_port1 = tcp1->dst_port;
+              new_port1 = tcp1->dst_port = s1->in2out.port;
+
+              sum1 = tcp1->checksum;
+              sum1 = ip_csum_update (sum1, old_addr1, new_addr1, ip4_header_t,
+                                     dst_address);
+              sum1 = ip_csum_update (sum1, old_port1, new_port1, ip4_header_t,
+                                     length);
+              if (is_twice_nat_session (s1))
+                {
+                  sum1 = ip_csum_update (sum1, ip1->src_address.as_u32,
+                                         s1->ext_host_nat_addr.as_u32,
+                                         ip4_header_t, dst_address);
+                  sum1 = ip_csum_update (sum1, tcp1->src_port,
+                                         s1->ext_host_nat_port, ip4_header_t,
+                                         length);
+                  tcp1->src_port = s1->ext_host_nat_port;
+                  ip1->src_address.as_u32 = s1->ext_host_nat_addr.as_u32;
+                }
+              tcp1->checksum = ip_csum_fold(sum1);
+              if (nat44_set_tcp_session_state_o2i (sm, s1, tcp1, thread_index))
+                goto trace01;
+            }
+          else
+            {
+              udp1->dst_port = s1->in2out.port;
+              if (is_twice_nat_session (s1))
+                {
+                  udp1->src_port = s1->ext_host_nat_port;
+                  ip1->src_address.as_u32 = s1->ext_host_nat_addr.as_u32;
+                }
+              udp1->checksum = 0;
+            }
+
+          /* Accounting */
+          nat44_session_update_counters (s1, now,
+                                         vlib_buffer_length_in_chain (vm, b1));
+          /* Per-user LRU list maintenance */
+          nat44_session_update_lru (sm, s1, thread_index);
+
+        trace01:
+          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)
+                            && (b1->flags & VLIB_BUFFER_IS_TRACED)))
+            {
+              nat44_ed_out2in_trace_t *t =
+                vlib_add_trace (vm, node, b1, sizeof (*t));
+              t->is_slow_path = is_slow_path;
+              t->sw_if_index = sw_if_index1;
+              t->next_index = next1;
+              t->session_index = ~0;
+              if (s1)
+                t->session_index = s1 - tsm->sessions;
+            }
+
+          pkts_processed += next1 != NAT44_ED_OUT2IN_NEXT_DROP;
+
+          /* verify speculative enqueues, maybe switch current next frame */
+          vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+                                           to_next, n_left_to_next,
+                                           bi0, bi1, next0, next1);
+        }
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+          u32 bi0;
+	  vlib_buffer_t *b0;
+          u32 next0, sw_if_index0, rx_fib_index0, proto0, old_addr0, new_addr0;
+          u16 old_port0, new_port0;
+          ip4_header_t *ip0;
+          udp_header_t *udp0;
+          tcp_header_t *tcp0;
+          icmp46_header_t * icmp0;
+          snat_session_t *s0 = 0;
+          clib_bihash_kv_16_8_t kv0, value0;
+          ip_csum_t sum0;
+          snat_session_key_t e_key0, l_key0;
+          u8 is_lb0;
+          twice_nat_type_t twice_nat0;
+
+          /* speculatively enqueue b0 to the current next frame */
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+          next0 = NAT44_ED_OUT2IN_NEXT_LOOKUP;
+          vnet_buffer (b0)->snat.flags = 0;
+          ip0 = vlib_buffer_get_current (b0);
+
+          sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_RX];
+	  rx_fib_index0 = fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
+                                                               sw_if_index0);
+
+          if (PREDICT_FALSE(ip0->ttl == 1))
+            {
+              vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+              icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
+                                           ICMP4_time_exceeded_ttl_exceeded_in_transit,
+                                           0);
+              next0 = NAT44_ED_OUT2IN_NEXT_ICMP_ERROR;
+              goto trace0;
+            }
+
+          udp0 = ip4_next_header (ip0);
+          tcp0 = (tcp_header_t *) udp0;
+          icmp0 = (icmp46_header_t *) udp0;
+          proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+          if (is_slow_path)
+            {
+              if (PREDICT_FALSE (proto0 == ~0))
+                {
+                  s0 = nat44_ed_out2in_unknown_proto(sm, b0, ip0, rx_fib_index0,
+                                                     thread_index, now, vm, node);
+                  if (!sm->forwarding_enabled)
+                    {
+                      if (!s0)
+                        next0 = NAT44_ED_OUT2IN_NEXT_DROP;
+                      goto trace0;
+                    }
+                }
+
+              if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
+                {
+                  next0 = icmp_out2in_slow_path
+                    (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
+                     next0, now, thread_index, &s0);
+                  goto trace0;
+                }
+            }
+          else
+            {
+              if (PREDICT_FALSE (proto0 == ~0 || proto0 == SNAT_PROTOCOL_ICMP))
+                {
+                  next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
+                  goto trace0;
+                }
+
+              if (ip4_is_fragment (ip0))
+                {
+                  b0->error = node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT];
+                  next0 = NAT44_ED_OUT2IN_NEXT_DROP;
+                  goto trace0;
+                }
+            }
+
+          make_ed_kv (&kv0, &ip0->dst_address, &ip0->src_address, ip0->protocol,
+                      rx_fib_index0, udp0->dst_port, udp0->src_port);
+
+          if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv0, &value0))
+            {
+              if (is_slow_path)
+                {
+                  /* Try to match static mapping by external address and port,
+                     destination address and port in packet */
+                  e_key0.addr = ip0->dst_address;
+                  e_key0.port = udp0->dst_port;
+                  e_key0.protocol = proto0;
+                  e_key0.fib_index = rx_fib_index0;
+                  if (snat_static_mapping_match(sm, e_key0, &l_key0, 1, 0,
+                      &twice_nat0, &is_lb0))
+                    {
+                      /*
+                       * Send DHCP packets to the ipv4 stack, or we won't
+                       * be able to use dhcp client on the outside interface
+                       */
+                      if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_UDP
+                          && (udp0->dst_port ==
+                          clib_host_to_net_u16(UDP_DST_PORT_dhcp_to_client))))
+                        {
+                          vnet_feature_next
+                            (vnet_buffer (b0)->sw_if_index[VLIB_RX], &next0, b0);
+                          goto trace0;
+                        }
+
+                      if (!sm->forwarding_enabled)
+                        {
+                          b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+                          next0 = NAT44_ED_OUT2IN_NEXT_DROP;
+                        }
+                      else
+                        {
+                          if (next_src_nat(sm, ip0, ip0->protocol,
+                                           udp0->src_port, udp0->dst_port,
+                                           thread_index))
+                            {
+                              next0 = NAT44_ED_OUT2IN_NEXT_IN2OUT;
+                              goto trace0;
+                            }
+                          create_bypass_for_fwd(sm, ip0, rx_fib_index0,
+                                                thread_index);
+                        }
+                      goto trace0;
+                    }
+
+                  /* Create session initiated by host from external network */
+                  s0 = create_session_for_static_mapping_ed(sm, b0, l_key0,
+                                                            e_key0, node,
+                                                            thread_index,
+                                                            twice_nat0, is_lb0);
+
+                  if (!s0)
+                    {
+                      next0 = NAT44_ED_OUT2IN_NEXT_DROP;
+                      goto trace0;
+                    }
+                }
+              else
+                {
+                  next0 = NAT44_ED_OUT2IN_NEXT_SLOW_PATH;
+                  goto trace0;
+                }
+            }
+          else
+            {
+              s0 = pool_elt_at_index (tsm->sessions, value0.value);
+            }
+
+          old_addr0 = ip0->dst_address.as_u32;
+          new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
+          vnet_buffer(b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+
+          sum0 = ip0->checksum;
+          sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                                 dst_address);
+          if (PREDICT_FALSE (is_twice_nat_session (s0)))
+            sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
+                                   s0->ext_host_nat_addr.as_u32, ip4_header_t,
+                                   src_address);
+          ip0->checksum = ip_csum_fold (sum0);
+
+          if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
+            {
+              old_port0 = tcp0->dst_port;
+              new_port0 = tcp0->dst_port = s0->in2out.port;
+
+              sum0 = tcp0->checksum;
+              sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                                     dst_address);
+              sum0 = ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
+                                     length);
+              if (is_twice_nat_session (s0))
+                {
+                  sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
+                                         s0->ext_host_nat_addr.as_u32,
+                                         ip4_header_t, dst_address);
+                  sum0 = ip_csum_update (sum0, tcp0->src_port,
+                                         s0->ext_host_nat_port, ip4_header_t,
+                                         length);
+                  tcp0->src_port = s0->ext_host_nat_port;
+                  ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
+                }
+              tcp0->checksum = ip_csum_fold(sum0);
+              if (nat44_set_tcp_session_state_o2i (sm, s0, tcp0, thread_index))
+                goto trace0;
+            }
+          else
+            {
+              udp0->dst_port = s0->in2out.port;
+              if (is_twice_nat_session (s0))
+                {
+                  udp0->src_port = s0->ext_host_nat_port;
+                  ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
+                }
+              udp0->checksum = 0;
+            }
+
+          /* Accounting */
+          nat44_session_update_counters (s0, now,
+                                         vlib_buffer_length_in_chain (vm, b0));
+          /* Per-user LRU list maintenance */
+          nat44_session_update_lru (sm, s0, thread_index);
+
+        trace0:
+          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)
+                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+            {
+              nat44_ed_out2in_trace_t *t =
+                vlib_add_trace (vm, node, b0, sizeof (*t));
+              t->is_slow_path = is_slow_path;
+              t->sw_if_index = sw_if_index0;
+              t->next_index = next0;
+              t->session_index = ~0;
+              if (s0)
+                t->session_index = s0 - tsm->sessions;
+            }
+
+          pkts_processed += next0 != NAT44_ED_OUT2IN_NEXT_DROP;
+
+          /* verify speculative enqueue, maybe switch current next frame */
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, next0);
+        }
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  vlib_node_increment_counter (vm, stats_node_index,
+                               SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
+                               pkts_processed);
+  return frame->n_vectors;
+}
+
+static uword
+nat44_ed_out2in_fast_path_fn (vlib_main_t * vm,
+                              vlib_node_runtime_t * node,
+                              vlib_frame_t * frame)
+{
+  return nat44_ed_out2in_node_fn_inline (vm, node, frame, 0);
+}
+
+VLIB_REGISTER_NODE (nat44_ed_out2in_node) = {
+  .function = nat44_ed_out2in_fast_path_fn,
+  .name = "nat44-ed-out2in",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat44_ed_out2in_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(snat_out2in_error_strings),
+  .error_strings = snat_out2in_error_strings,
+
+  .runtime_data_bytes = sizeof (snat_runtime_t),
+
+  .n_next_nodes = NAT44_ED_OUT2IN_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [NAT44_ED_OUT2IN_NEXT_DROP] = "error-drop",
+    [NAT44_ED_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT44_ED_OUT2IN_NEXT_SLOW_PATH] = "nat44-ed-out2in-slowpath",
+    [NAT44_ED_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT44_ED_OUT2IN_NEXT_IN2OUT] = "nat44-ed-in2out",
+  },
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_out2in_node, nat44_ed_out2in_fast_path_fn);
+
+static uword
+nat44_ed_out2in_slow_path_fn (vlib_main_t * vm,
+                              vlib_node_runtime_t * node,
+                              vlib_frame_t * frame)
+{
+  return nat44_ed_out2in_node_fn_inline (vm, node, frame, 1);
+}
+
+VLIB_REGISTER_NODE (nat44_ed_out2in_slowpath_node) = {
+  .function = nat44_ed_out2in_slow_path_fn,
+  .name = "nat44-ed-out2in-slowpath",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat44_ed_out2in_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(snat_out2in_error_strings),
+  .error_strings = snat_out2in_error_strings,
+
+  .runtime_data_bytes = sizeof (snat_runtime_t),
+
+  .n_next_nodes = NAT44_ED_OUT2IN_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [NAT44_ED_OUT2IN_NEXT_DROP] = "error-drop",
+    [NAT44_ED_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT44_ED_OUT2IN_NEXT_SLOW_PATH] = "nat44-ed-out2in-slowpath",
+    [NAT44_ED_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT44_ED_OUT2IN_NEXT_IN2OUT] = "nat44-ed-in2out",
+  },
+};
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_out2in_slowpath_node,
+                              nat44_ed_out2in_slow_path_fn);
+
 /**************************/
 /*** deterministic mode ***/
 /**************************/
@@ -2535,7 +3309,6 @@ VLIB_REGISTER_NODE (snat_det_out2in_node) = {
     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
-    [SNAT_OUT2IN_NEXT_IN2OUT] = "nat44-in2out",
   },
 };
 VLIB_NODE_FUNCTION_MULTIARCH (snat_det_out2in_node, snat_det_out2in_node_fn);
@@ -3058,7 +3831,6 @@ VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
     [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
-    [SNAT_OUT2IN_NEXT_IN2OUT] = "nat44-in2out",
   },
 };
 VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_fast_node, snat_out2in_fast_node_fn);