NAT: Refactoring / Housekeeping (VPP-1415)

Change-Id: Ia3ce24cc94f9b2fb331ad62a4181ddcd41bc78ca
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 2067 insertions, 0 deletions

diff --git a/src/plugins/nat/in2out_ed.c b/src/plugins/nat/in2out_ed.c
new file mode 100644
index 00000000000..d4f70f5a12b
--- /dev/null
+++ b/src/plugins/nat/in2out_ed.c
@@ -0,0 +1,2067 @@
+/*
+ * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @file
+ * @brief NAT44 endpoint-dependent inside to outside network translation
+ */
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vnet/ip/ip.h>
+#include <vnet/ethernet/ethernet.h>
+#include <vnet/fib/ip4_fib.h>
+#include <vppinfra/error.h>
+#include <nat/nat.h>
+#include <nat/nat_ipfix_logging.h>
+#include <nat/nat_reass.h>
+#include <nat/nat_inlines.h>
+
+#define foreach_nat_in2out_ed_error                       \
+_(UNSUPPORTED_PROTOCOL, "Unsupported protocol")         \
+_(IN2OUT_PACKETS, "Good in2out packets processed")      \
+_(OUT_OF_PORTS, "Out of ports")                         \
+_(BAD_ICMP_TYPE, "unsupported ICMP type")               \
+_(MAX_SESSIONS_EXCEEDED, "Maximum sessions exceeded")   \
+_(DROP_FRAGMENT, "Drop fragment")                       \
+_(MAX_REASS, "Maximum reassemblies exceeded")           \
+_(MAX_FRAG, "Maximum fragments per reassembly exceeded")
+
+typedef enum
+{
+#define _(sym,str) NAT_IN2OUT_ED_ERROR_##sym,
+  foreach_nat_in2out_ed_error
+#undef _
+    NAT_IN2OUT_ED_N_ERROR,
+} nat_in2out_ed_error_t;
+
+static char *nat_in2out_ed_error_strings[] = {
+#define _(sym,string) string,
+  foreach_nat_in2out_ed_error
+#undef _
+};
+
+typedef enum
+{
+  NAT_IN2OUT_ED_NEXT_LOOKUP,
+  NAT_IN2OUT_ED_NEXT_DROP,
+  NAT_IN2OUT_ED_NEXT_ICMP_ERROR,
+  NAT_IN2OUT_ED_NEXT_SLOW_PATH,
+  NAT_IN2OUT_ED_NEXT_REASS,
+  NAT_IN2OUT_ED_N_NEXT,
+} nat_in2out_ed_next_t;
+
+typedef struct
+{
+  u32 sw_if_index;
+  u32 next_index;
+  u32 session_index;
+  u32 is_slow_path;
+} nat_in2out_ed_trace_t;
+
+vlib_node_registration_t nat44_ed_in2out_node;
+vlib_node_registration_t nat44_ed_in2out_slowpath_node;
+vlib_node_registration_t nat44_ed_in2out_output_node;
+vlib_node_registration_t nat44_ed_in2out_output_slowpath_node;
+vlib_node_registration_t nat44_ed_in2out_reass_node;
+
+static u8 *
+format_nat_in2out_ed_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 *);
+  nat_in2out_ed_trace_t *t = va_arg (*args, nat_in2out_ed_trace_t *);
+  char *tag;
+
+  tag =
+    t->is_slow_path ? "NAT44_IN2OUT_ED_SLOW_PATH" :
+    "NAT44_IN2OUT_ED_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_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 = 0;
+  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->src_address;
+      key0.r_addr = ip0->dst_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.r_addr = inner_ip0->src_address;
+      key0.l_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.r_port = 0;
+	  key0.l_port = inner_echo0->identifier;
+	  break;
+	case SNAT_PROTOCOL_UDP:
+	case SNAT_PROTOCOL_TCP:
+	  key0.l_port = ((tcp_udp_header_t *) l4_header)->dst_port;
+	  key0.r_port = ((tcp_udp_header_t *) l4_header)->src_port;
+	  break;
+	default:
+	  return NAT_IN2OUT_ED_ERROR_UNSUPPORTED_PROTOCOL;
+	}
+    }
+  *p_key0 = key0;
+  return 0;
+}
+
+int
+nat44_i2o_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg)
+{
+  snat_main_t *sm = &snat_main;
+  nat44_is_idle_session_ctx_t *ctx = arg;
+  snat_session_t *s;
+  u64 sess_timeout_time;
+  nat_ed_ses_key_t ed_key;
+  clib_bihash_kv_16_8_t ed_kv;
+  int i;
+  snat_address_t *a;
+  snat_session_key_t key;
+  snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
+						       ctx->thread_index);
+
+  s = pool_elt_at_index (tsm->sessions, kv->value);
+  sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
+  if (ctx->now >= sess_timeout_time)
+    {
+      if (is_fwd_bypass_session (s))
+	goto delete;
+
+      ed_key.l_addr = s->out2in.addr;
+      ed_key.r_addr = s->ext_host_addr;
+      ed_key.fib_index = s->out2in.fib_index;
+      if (snat_is_unk_proto_session (s))
+	{
+	  ed_key.proto = s->in2out.port;
+	  ed_key.r_port = 0;
+	  ed_key.l_port = 0;
+	}
+      else
+	{
+	  ed_key.proto = snat_proto_to_ip_proto (s->in2out.protocol);
+	  ed_key.l_port = s->out2in.port;
+	  ed_key.r_port = s->ext_host_port;
+	}
+      ed_kv.key[0] = ed_key.as_u64[0];
+      ed_kv.key[1] = ed_key.as_u64[1];
+      if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &ed_kv, 0))
+	nat_log_warn ("out2in_ed key del failed");
+
+      if (snat_is_unk_proto_session (s))
+	goto delete;
+
+      snat_ipfix_logging_nat44_ses_delete (s->in2out.addr.as_u32,
+					   s->out2in.addr.as_u32,
+					   s->in2out.protocol,
+					   s->in2out.port,
+					   s->out2in.port,
+					   s->in2out.fib_index);
+
+      if (is_twice_nat_session (s))
+	{
+	  for (i = 0; i < vec_len (sm->twice_nat_addresses); i++)
+	    {
+	      key.protocol = s->in2out.protocol;
+	      key.port = s->ext_host_nat_port;
+	      a = sm->twice_nat_addresses + i;
+	      if (a->addr.as_u32 == s->ext_host_nat_addr.as_u32)
+		{
+		  snat_free_outside_address_and_port (sm->twice_nat_addresses,
+						      ctx->thread_index,
+						      &key);
+		  break;
+		}
+	    }
+	}
+
+      if (snat_is_session_static (s))
+	goto delete;
+
+      snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
+					  &s->out2in);
+    delete:
+      nat44_delete_session (sm, s, ctx->thread_index);
+      return 1;
+    }
+
+  return 0;
+}
+
+static inline u32
+icmp_in2out_ed_slow_path (snat_main_t * sm, vlib_buffer_t * b0,
+			  ip4_header_t * ip0, icmp46_header_t * icmp0,
+			  u32 sw_if_index0, u32 rx_fib_index0,
+			  vlib_node_runtime_t * node, u32 next0, f64 now,
+			  u32 thread_index, snat_session_t ** p_s0)
+{
+  next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
+		       next0, thread_index, p_s0, 0);
+  snat_session_t *s0 = *p_s0;
+  if (PREDICT_TRUE (next0 != NAT_IN2OUT_ED_NEXT_DROP && s0))
+    {
+      /* Hairpinning */
+      if (vnet_buffer (b0)->sw_if_index[VLIB_TX] == ~0)
+	snat_icmp_hairpinning (sm, b0, ip0, icmp0, sm->endpoint_dependent);
+      /* Accounting */
+      nat44_session_update_counters (s0, now,
+				     vlib_buffer_length_in_chain
+				     (sm->vlib_main, b0));
+    }
+  return next0;
+}
+
+static u32
+slow_path_ed (snat_main_t * sm,
+	      vlib_buffer_t * b,
+	      u32 rx_fib_index,
+	      clib_bihash_kv_16_8_t * kv,
+	      snat_session_t ** sessionp,
+	      vlib_node_runtime_t * node, u32 next, u32 thread_index, f64 now)
+{
+  snat_session_t *s;
+  snat_user_t *u;
+  snat_session_key_t key0, key1;
+  lb_nat_type_t lb = 0, is_sm = 0;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  nat_ed_ses_key_t *key = (nat_ed_ses_key_t *) kv->key;
+  u32 proto = ip_proto_to_snat_proto (key->proto);
+  nat_outside_fib_t *outside_fib;
+  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
+  fib_prefix_t pfx = {
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_len = 32,
+    .fp_addr = {
+		.ip4.as_u32 = key->r_addr.as_u32,
+		},
+  };
+  nat44_is_idle_session_ctx_t ctx;
+
+  if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+    {
+      b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
+      nat_ipfix_logging_max_sessions (sm->max_translations);
+      nat_log_notice ("maximum sessions exceeded");
+      return NAT_IN2OUT_ED_NEXT_DROP;
+    }
+
+  key0.addr = key->l_addr;
+  key0.port = key->l_port;
+  key1.protocol = key0.protocol = proto;
+  key0.fib_index = rx_fib_index;
+  key1.fib_index = sm->outside_fib_index;
+  /* First try to match static mapping by local address and port */
+  if (snat_static_mapping_match (sm, key0, &key1, 0, 0, 0, &lb, 0))
+    {
+      /* Try to create dynamic translation */
+      if (snat_alloc_outside_address_and_port (sm->addresses, rx_fib_index,
+					       thread_index, &key1,
+					       sm->port_per_thread,
+					       tsm->snat_thread_index))
+	{
+	  nat_log_notice ("addresses exhausted");
+	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_OUT_OF_PORTS];
+	  return NAT_IN2OUT_ED_NEXT_DROP;
+	}
+    }
+  else
+    is_sm = 1;
+
+  u = nat_user_get_or_create (sm, &key->l_addr, rx_fib_index, thread_index);
+  if (!u)
+    {
+      nat_log_warn ("create NAT user failed");
+      if (!is_sm)
+	snat_free_outside_address_and_port (sm->addresses,
+					    thread_index, &key1);
+      return NAT_IN2OUT_ED_NEXT_DROP;
+    }
+
+  s = nat_ed_session_alloc (sm, u, thread_index);
+  if (!s)
+    {
+      nat44_delete_user_with_no_session (sm, u, thread_index);
+      nat_log_warn ("create NAT session failed");
+      if (!is_sm)
+	snat_free_outside_address_and_port (sm->addresses,
+					    thread_index, &key1);
+      return NAT_IN2OUT_ED_NEXT_DROP;
+    }
+
+  user_session_increment (sm, u, is_sm);
+  if (is_sm)
+    s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
+  if (lb)
+    s->flags |= SNAT_SESSION_FLAG_LOAD_BALANCING;
+  s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
+  s->ext_host_addr = key->r_addr;
+  s->ext_host_port = key->r_port;
+  s->in2out = key0;
+  s->out2in = key1;
+  s->out2in.protocol = key0.protocol;
+
+  switch (vec_len (sm->outside_fibs))
+    {
+    case 0:
+      s->out2in.fib_index = sm->outside_fib_index;
+      break;
+    case 1:
+      s->out2in.fib_index = sm->outside_fibs[0].fib_index;
+      break;
+    default:
+      /* *INDENT-OFF* */
+      vec_foreach (outside_fib, sm->outside_fibs)
+       {
+          fei = fib_table_lookup (outside_fib->fib_index, &pfx);
+          if (FIB_NODE_INDEX_INVALID != fei)
+            {
+              if (fib_entry_get_resolving_interface (fei) != ~0)
+                {
+                  s->out2in.fib_index = outside_fib->fib_index;
+                  break;
+                }
+            }
+        }
+      /* *INDENT-ON* */
+      break;
+    }
+
+  /* Add to lookup tables */
+  kv->value = s - tsm->sessions;
+  ctx.now = now;
+  ctx.thread_index = thread_index;
+  if (clib_bihash_add_or_overwrite_stale_16_8 (&tsm->in2out_ed, kv,
+					       nat44_i2o_ed_is_idle_session_cb,
+					       &ctx))
+    nat_log_notice ("in2out-ed key add failed");
+
+  make_ed_kv (kv, &key1.addr, &key->r_addr, key->proto, s->out2in.fib_index,
+	      key1.port, key->r_port);
+  kv->value = s - tsm->sessions;
+  if (clib_bihash_add_or_overwrite_stale_16_8 (&tsm->out2in_ed, kv,
+					       nat44_o2i_ed_is_idle_session_cb,
+					       &ctx))
+    nat_log_notice ("out2in-ed key add failed");
+
+  *sessionp = s;
+
+  /* log NAT event */
+  snat_ipfix_logging_nat44_ses_create (s->in2out.addr.as_u32,
+				       s->out2in.addr.as_u32,
+				       s->in2out.protocol,
+				       s->in2out.port,
+				       s->out2in.port, s->in2out.fib_index);
+  return next;
+}
+
+static_always_inline int
+nat44_ed_not_translate (snat_main_t * sm, vlib_node_runtime_t * node,
+			u32 sw_if_index, ip4_header_t * ip, u32 proto,
+			u32 rx_fib_index, u32 thread_index)
+{
+  udp_header_t *udp = ip4_next_header (ip);
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  clib_bihash_kv_16_8_t kv, value;
+  snat_session_key_t key0, key1;
+
+  make_ed_kv (&kv, &ip->dst_address, &ip->src_address, ip->protocol,
+	      sm->outside_fib_index, udp->dst_port, udp->src_port);
+
+  /* NAT packet aimed at external address if */
+  /* has active sessions */
+  if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv, &value))
+    {
+      key0.addr = ip->dst_address;
+      key0.port = udp->dst_port;
+      key0.protocol = proto;
+      key0.fib_index = sm->outside_fib_index;
+      /* or is static mappings */
+      if (!snat_static_mapping_match (sm, key0, &key1, 1, 0, 0, 0, 0))
+	return 0;
+    }
+  else
+    return 0;
+
+  if (sm->forwarding_enabled)
+    return 1;
+
+  return snat_not_translate_fast (sm, node, sw_if_index, ip, proto,
+				  rx_fib_index);
+}
+
+static_always_inline int
+nat_not_translate_output_feature_fwd (snat_main_t * sm, ip4_header_t * ip,
+				      u32 thread_index, f64 now,
+				      vlib_main_t * vm, vlib_buffer_t * b)
+{
+  nat_ed_ses_key_t key;
+  clib_bihash_kv_16_8_t kv, value;
+  udp_header_t *udp;
+  snat_session_t *s = 0;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+
+  if (!sm->forwarding_enabled)
+    return 0;
+
+  if (ip->protocol == IP_PROTOCOL_ICMP)
+    {
+      key.as_u64[0] = key.as_u64[1] = 0;
+      if (icmp_get_ed_key (ip, &key))
+	return 0;
+      key.fib_index = 0;
+      kv.key[0] = key.as_u64[0];
+      kv.key[1] = key.as_u64[1];
+    }
+  else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
+    {
+      udp = ip4_next_header (ip);
+      make_ed_kv (&kv, &ip->src_address, &ip->dst_address, ip->protocol, 0,
+		  udp->src_port, udp->dst_port);
+    }
+  else
+    {
+      make_ed_kv (&kv, &ip->src_address, &ip->dst_address, ip->protocol, 0, 0,
+		  0);
+    }
+
+  if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
+    {
+      s = pool_elt_at_index (tsm->sessions, value.value);
+      if (is_fwd_bypass_session (s))
+	{
+	  if (ip->protocol == IP_PROTOCOL_TCP)
+	    {
+	      tcp_header_t *tcp = ip4_next_header (ip);
+	      if (nat44_set_tcp_session_state_i2o (sm, s, tcp, thread_index))
+		return 1;
+	    }
+	  /* Accounting */
+	  nat44_session_update_counters (s, now,
+					 vlib_buffer_length_in_chain (vm, b));
+	  return 1;
+	}
+      else
+	return 0;
+    }
+
+  return 0;
+}
+
+static_always_inline int
+nat44_ed_not_translate_output_feature (snat_main_t * sm, ip4_header_t * ip,
+				       u8 proto, u16 src_port, u16 dst_port,
+				       u32 thread_index, u32 rx_sw_if_index,
+				       u32 tx_sw_if_index)
+{
+  clib_bihash_kv_16_8_t kv, value;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  snat_interface_t *i;
+  snat_session_t *s;
+  u32 rx_fib_index = ip4_fib_table_get_index_for_sw_if_index (rx_sw_if_index);
+  u32 tx_fib_index = ip4_fib_table_get_index_for_sw_if_index (tx_sw_if_index);
+
+  /* src NAT check */
+  make_ed_kv (&kv, &ip->src_address, &ip->dst_address, proto, tx_fib_index,
+	      src_port, dst_port);
+  if (!clib_bihash_search_16_8 (&tsm->out2in_ed, &kv, &value))
+    return 1;
+
+  /* dst NAT check */
+  make_ed_kv (&kv, &ip->dst_address, &ip->src_address, proto, rx_fib_index,
+	      dst_port, src_port);
+  if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
+    {
+      s = pool_elt_at_index (tsm->sessions, value.value);
+      if (is_fwd_bypass_session (s))
+	return 0;
+
+      /* hairpinning */
+      /* *INDENT-OFF* */
+      pool_foreach (i, sm->output_feature_interfaces,
+      ({
+        if ((nat_interface_is_inside (i)) && (rx_sw_if_index == i->sw_if_index))
+           return 0;
+      }));
+      /* *INDENT-ON* */
+      return 1;
+    }
+
+  return 0;
+}
+
+u32
+icmp_match_in2out_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)
+{
+  icmp46_header_t *icmp;
+  u32 sw_if_index;
+  u32 rx_fib_index;
+  nat_ed_ses_key_t key;
+  snat_session_t *s = 0;
+  u8 dont_translate = 0;
+  clib_bihash_kv_16_8_t kv, value;
+  u32 next = ~0;
+  int err;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+
+  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);
+
+  key.as_u64[0] = key.as_u64[1] = 0;
+  err = icmp_get_ed_key (ip, &key);
+  if (err != 0)
+    {
+      b->error = node->errors[err];
+      next = NAT_IN2OUT_ED_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->in2out_ed, &kv, &value))
+    {
+      if (vnet_buffer (b)->sw_if_index[VLIB_TX] != ~0)
+	{
+	  if (PREDICT_FALSE (nat44_ed_not_translate_output_feature (sm, ip,
+								    key.proto,
+								    key.
+								    l_port,
+								    key.
+								    r_port,
+								    thread_index,
+								    sw_if_index,
+								    vnet_buffer
+								    (b)->
+								    sw_if_index
+								    [VLIB_TX])))
+	    {
+	      dont_translate = 1;
+	      goto out;
+	    }
+	}
+      else
+	{
+	  if (PREDICT_FALSE (nat44_ed_not_translate (sm, node, sw_if_index,
+						     ip, SNAT_PROTOCOL_ICMP,
+						     rx_fib_index,
+						     thread_index)))
+	    {
+	      dont_translate = 1;
+	      goto out;
+	    }
+	}
+
+      if (PREDICT_FALSE (icmp_is_error_message (icmp)))
+	{
+	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_BAD_ICMP_TYPE];
+	  next = NAT_IN2OUT_ED_NEXT_DROP;
+	  goto out;
+	}
+
+      next = slow_path_ed (sm, b, rx_fib_index, &kv, &s, node, next,
+			   thread_index, vlib_time_now (sm->vlib_main));
+
+      if (PREDICT_FALSE (next == NAT_IN2OUT_ED_NEXT_DROP))
+	goto out;
+    }
+  else
+    {
+      if (PREDICT_FALSE (icmp->type != ICMP4_echo_request &&
+			 icmp->type != ICMP4_echo_reply &&
+			 !icmp_is_error_message (icmp)))
+	{
+	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_BAD_ICMP_TYPE];
+	  next = NAT_IN2OUT_ED_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->out2in;
+  *p_dont_translate = dont_translate;
+  if (d)
+    *(snat_session_t **) d = s;
+  return next;
+}
+
+static snat_session_t *
+nat44_ed_in2out_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 = 0;
+  ip_csum_t sum;
+  snat_user_t *u;
+  dlist_elt_t *head, *elt;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  u32 elt_index, head_index, ses_index;
+  snat_session_t *s;
+  u32 outside_fib_index = sm->outside_fib_index;
+  int i;
+  u8 is_sm = 0;
+  nat_outside_fib_t *outside_fib;
+  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
+  fib_prefix_t pfx = {
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_len = 32,
+    .fp_addr = {
+		.ip4.as_u32 = ip->dst_address.as_u32,
+		},
+  };
+
+  switch (vec_len (sm->outside_fibs))
+    {
+    case 0:
+      outside_fib_index = sm->outside_fib_index;
+      break;
+    case 1:
+      outside_fib_index = sm->outside_fibs[0].fib_index;
+      break;
+    default:
+      /* *INDENT-OFF* */
+      vec_foreach (outside_fib, sm->outside_fibs)
+        {
+	  fei = fib_table_lookup (outside_fib->fib_index, &pfx);
+	  if (FIB_NODE_INDEX_INVALID != fei)
+	    {
+	      if (fib_entry_get_resolving_interface (fei) != ~0)
+	        {
+		  outside_fib_index = outside_fib->fib_index;
+		  break;
+	        }
+	    }
+        }
+      /* *INDENT-ON* */
+      break;
+    }
+  old_addr = ip->src_address.as_u32;
+
+  make_ed_kv (&s_kv, &ip->src_address, &ip->dst_address, ip->protocol,
+	      rx_fib_index, 0, 0);
+
+  if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &s_kv, &s_value))
+    {
+      s = pool_elt_at_index (tsm->sessions, s_value.value);
+      new_addr = ip->src_address.as_u32 = s->out2in.addr.as_u32;
+    }
+  else
+    {
+      if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+	{
+	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
+	  nat_ipfix_logging_max_sessions (sm->max_translations);
+	  nat_log_notice ("maximum sessions exceeded");
+	  return 0;
+	}
+
+      u = nat_user_get_or_create (sm, &ip->src_address, rx_fib_index,
+				  thread_index);
+      if (!u)
+	{
+	  nat_log_warn ("create NAT user failed");
+	  return 0;
+	}
+
+      make_sm_kv (&kv, &ip->src_address, 0, rx_fib_index, 0);
+
+      /* Try to find static mapping first */
+      if (!clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv, &value))
+	{
+	  m = pool_elt_at_index (sm->static_mappings, value.value);
+	  new_addr = ip->src_address.as_u32 = m->external_addr.as_u32;
+	  is_sm = 1;
+	  goto create_ses;
+	}
+      /* Fallback to 3-tuple key */
+      else
+	{
+	  /* Choose same out address as for TCP/UDP session to same destination */
+	  head_index = u->sessions_per_user_list_head_index;
+	  head = pool_elt_at_index (tsm->list_pool, head_index);
+	  elt_index = head->next;
+	  if (PREDICT_FALSE (elt_index == ~0))
+	    ses_index = ~0;
+	  else
+	    {
+	      elt = pool_elt_at_index (tsm->list_pool, elt_index);
+	      ses_index = elt->value;
+	    }
+
+	  while (ses_index != ~0)
+	    {
+	      s = pool_elt_at_index (tsm->sessions, ses_index);
+	      elt_index = elt->next;
+	      elt = pool_elt_at_index (tsm->list_pool, elt_index);
+	      ses_index = elt->value;
+
+	      if (s->ext_host_addr.as_u32 == ip->dst_address.as_u32)
+		{
+		  new_addr = ip->src_address.as_u32 = s->out2in.addr.as_u32;
+
+		  make_ed_kv (&s_kv, &s->out2in.addr, &ip->dst_address,
+			      ip->protocol, outside_fib_index, 0, 0);
+		  if (clib_bihash_search_16_8
+		      (&tsm->out2in_ed, &s_kv, &s_value))
+		    goto create_ses;
+
+		  break;
+		}
+	    }
+
+	  for (i = 0; i < vec_len (sm->addresses); i++)
+	    {
+	      make_ed_kv (&s_kv, &sm->addresses[i].addr, &ip->dst_address,
+			  ip->protocol, outside_fib_index, 0, 0);
+	      if (clib_bihash_search_16_8 (&tsm->out2in_ed, &s_kv, &s_value))
+		{
+		  new_addr = ip->src_address.as_u32 =
+		    sm->addresses[i].addr.as_u32;
+		  goto create_ses;
+		}
+	    }
+	  return 0;
+	}
+
+    create_ses:
+      s = nat_ed_session_alloc (sm, u, thread_index);
+      if (!s)
+	{
+	  nat44_delete_user_with_no_session (sm, u, thread_index);
+	  nat_log_warn ("create NAT session failed");
+	  return 0;
+	}
+
+      s->ext_host_addr.as_u32 = ip->dst_address.as_u32;
+      s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
+      s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
+      s->out2in.addr.as_u32 = new_addr;
+      s->out2in.fib_index = outside_fib_index;
+      s->in2out.addr.as_u32 = old_addr;
+      s->in2out.fib_index = rx_fib_index;
+      s->in2out.port = s->out2in.port = ip->protocol;
+      if (is_sm)
+	s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
+      user_session_increment (sm, u, is_sm);
+
+      /* Add to lookup tables */
+      make_ed_kv (&s_kv, &s->in2out.addr, &ip->dst_address, ip->protocol,
+		  rx_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");
+
+      make_ed_kv (&s_kv, &s->out2in.addr, &ip->dst_address, ip->protocol,
+		  outside_fib_index, 0, 0);
+      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");
+    }
+
+  /* Update IP checksum */
+  sum = ip->checksum;
+  sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, src_address);
+  ip->checksum = ip_csum_fold (sum);
+
+  /* Accounting */
+  nat44_session_update_counters (s, now, vlib_buffer_length_in_chain (vm, b));
+
+  /* Hairpinning */
+  if (vnet_buffer (b)->sw_if_index[VLIB_TX] == ~0)
+    nat44_ed_hairpinning_unknown_proto (sm, b, ip);
+
+  if (vnet_buffer (b)->sw_if_index[VLIB_TX] == ~0)
+    vnet_buffer (b)->sw_if_index[VLIB_TX] = outside_fib_index;
+
+  return s;
+}
+
+static inline uword
+nat44_ed_in2out_node_fn_inline (vlib_main_t * vm,
+				vlib_node_runtime_t * node,
+				vlib_frame_t * frame, int is_slow_path,
+				int is_output_feature)
+{
+  u32 n_left_from, *from, *to_next, pkts_processed = 0, stats_node_index;
+  nat_in2out_ed_next_t next_index;
+  snat_main_t *sm = &snat_main;
+  f64 now = vlib_time_now (vm);
+  u32 thread_index = vm->thread_index;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+
+  stats_node_index = is_slow_path ? nat44_ed_in2out_slowpath_node.index :
+    nat44_ed_in2out_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, iph_offset0 = 0, proto0,
+	    new_addr0, old_addr0;
+	  u32 next1, sw_if_index1, rx_fib_index1, iph_offset1 = 0, proto1,
+	    new_addr1, old_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;
+
+	  /* 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 = NAT_IN2OUT_ED_NEXT_LOOKUP;
+
+	  if (is_output_feature)
+	    iph_offset0 = vnet_buffer (b0)->ip.save_rewrite_length;
+
+	  ip0 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
+				  iph_offset0);
+
+	  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 = NAT_IN2OUT_ED_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_in2out_unknown_proto (sm, b0, ip0,
+						      rx_fib_index0,
+						      thread_index, now, vm,
+						      node);
+		  if (!s0)
+		    next0 = NAT_IN2OUT_ED_NEXT_DROP;
+		  goto trace00;
+		}
+
+	      if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
+		{
+		  next0 = icmp_in2out_ed_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))
+		{
+		  next0 = NAT_IN2OUT_ED_NEXT_SLOW_PATH;
+		  goto trace00;
+		}
+
+	      if (ip4_is_fragment (ip0))
+		{
+		  next0 = NAT_IN2OUT_ED_NEXT_REASS;
+		  goto trace00;
+		}
+
+	      if (is_output_feature)
+		{
+		  if (PREDICT_FALSE
+		      (nat_not_translate_output_feature_fwd
+		       (sm, ip0, thread_index, now, vm, b0)))
+		    goto trace00;
+		}
+
+	      if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
+		{
+		  next0 = NAT_IN2OUT_ED_NEXT_SLOW_PATH;
+		  goto trace00;
+		}
+	    }
+
+	  make_ed_kv (&kv0, &ip0->src_address, &ip0->dst_address,
+		      ip0->protocol, rx_fib_index0, udp0->src_port,
+		      udp0->dst_port);
+
+	  if (clib_bihash_search_16_8 (&tsm->in2out_ed, &kv0, &value0))
+	    {
+	      if (is_slow_path)
+		{
+		  if (is_output_feature)
+		    {
+		      if (PREDICT_FALSE
+			  (nat44_ed_not_translate_output_feature
+			   (sm, ip0, ip0->protocol, udp0->src_port,
+			    udp0->dst_port, thread_index, sw_if_index0,
+			    vnet_buffer (b0)->sw_if_index[VLIB_TX])))
+			goto trace00;
+		    }
+		  else
+		    {
+		      if (PREDICT_FALSE (nat44_ed_not_translate (sm, node,
+								 sw_if_index0,
+								 ip0, proto0,
+								 rx_fib_index0,
+								 thread_index)))
+			goto trace00;
+		    }
+
+		  next0 =
+		    slow_path_ed (sm, b0, rx_fib_index0, &kv0, &s0, node,
+				  next0, thread_index, now);
+
+		  if (PREDICT_FALSE (next0 == NAT_IN2OUT_ED_NEXT_DROP))
+		    goto trace00;
+		}
+	      else
+		{
+		  next0 = NAT_IN2OUT_ED_NEXT_SLOW_PATH;
+		  goto trace00;
+		}
+	    }
+	  else
+	    {
+	      s0 = pool_elt_at_index (tsm->sessions, value0.value);
+	    }
+
+	  b0->flags |= VNET_BUFFER_F_IS_NATED;
+
+	  if (!is_output_feature)
+	    vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
+
+	  old_addr0 = ip0->src_address.as_u32;
+	  new_addr0 = ip0->src_address.as_u32 = s0->out2in.addr.as_u32;
+	  sum0 = ip0->checksum;
+	  sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+				 src_address);
+	  if (PREDICT_FALSE (is_twice_nat_session (s0)))
+	    sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
+				   s0->ext_host_addr.as_u32, ip4_header_t,
+				   dst_address);
+	  ip0->checksum = ip_csum_fold (sum0);
+
+	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
+	    {
+	      old_port0 = tcp0->src_port;
+	      new_port0 = tcp0->src_port = s0->out2in.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 (PREDICT_FALSE (is_twice_nat_session (s0)))
+		{
+		  sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
+					 s0->ext_host_addr.as_u32,
+					 ip4_header_t, dst_address);
+		  sum0 = ip_csum_update (sum0, tcp0->dst_port,
+					 s0->ext_host_port, ip4_header_t,
+					 length);
+		  tcp0->dst_port = s0->ext_host_port;
+		  ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
+		}
+	      mss_clamping (sm, tcp0, &sum0);
+	      tcp0->checksum = ip_csum_fold (sum0);
+	      if (nat44_set_tcp_session_state_i2o
+		  (sm, s0, tcp0, thread_index))
+		goto trace00;
+	    }
+	  else
+	    {
+	      udp0->src_port = s0->out2in.port;
+	      udp0->checksum = 0;
+	      if (PREDICT_FALSE (is_twice_nat_session (s0)))
+		{
+		  udp0->dst_port = s0->ext_host_port;
+		  ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
+		}
+	    }
+
+	  /* Accounting */
+	  nat44_session_update_counters (s0, now,
+					 vlib_buffer_length_in_chain (vm,
+								      b0));
+
+	trace00:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      nat_in2out_ed_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 != NAT_IN2OUT_ED_NEXT_DROP;
+
+
+	  next1 = NAT_IN2OUT_ED_NEXT_LOOKUP;
+
+	  if (is_output_feature)
+	    iph_offset1 = vnet_buffer (b1)->ip.save_rewrite_length;
+
+	  ip1 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b1) +
+				  iph_offset1);
+
+	  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 = NAT_IN2OUT_ED_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_in2out_unknown_proto (sm, b1, ip1,
+						      rx_fib_index1,
+						      thread_index, now, vm,
+						      node);
+		  if (!s1)
+		    next1 = NAT_IN2OUT_ED_NEXT_DROP;
+		  goto trace01;
+		}
+
+	      if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
+		{
+		  next1 = icmp_in2out_ed_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))
+		{
+		  next1 = NAT_IN2OUT_ED_NEXT_SLOW_PATH;
+		  goto trace01;
+		}
+
+	      if (ip4_is_fragment (ip1))
+		{
+		  next1 = NAT_IN2OUT_ED_NEXT_REASS;
+		  goto trace01;
+		}
+
+	      if (is_output_feature)
+		{
+		  if (PREDICT_FALSE
+		      (nat_not_translate_output_feature_fwd
+		       (sm, ip1, thread_index, now, vm, b1)))
+		    goto trace01;
+		}
+
+	      if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
+		{
+		  next1 = NAT_IN2OUT_ED_NEXT_SLOW_PATH;
+		  goto trace01;
+		}
+	    }
+
+	  make_ed_kv (&kv1, &ip1->src_address, &ip1->dst_address,
+		      ip1->protocol, rx_fib_index1, udp1->src_port,
+		      udp1->dst_port);
+
+	  if (clib_bihash_search_16_8 (&tsm->in2out_ed, &kv1, &value1))
+	    {
+	      if (is_slow_path)
+		{
+		  if (is_output_feature)
+		    {
+		      if (PREDICT_FALSE
+			  (nat44_ed_not_translate_output_feature
+			   (sm, ip1, ip1->protocol, udp1->src_port,
+			    udp1->dst_port, thread_index, sw_if_index1,
+			    vnet_buffer (b1)->sw_if_index[VLIB_TX])))
+			goto trace01;
+		    }
+		  else
+		    {
+		      if (PREDICT_FALSE (nat44_ed_not_translate (sm, node,
+								 sw_if_index1,
+								 ip1, proto1,
+								 rx_fib_index1,
+								 thread_index)))
+			goto trace01;
+		    }
+
+		  next1 =
+		    slow_path_ed (sm, b1, rx_fib_index1, &kv1, &s1, node,
+				  next1, thread_index, now);
+
+		  if (PREDICT_FALSE (next1 == NAT_IN2OUT_ED_NEXT_DROP))
+		    goto trace01;
+		}
+	      else
+		{
+		  next1 = NAT_IN2OUT_ED_NEXT_SLOW_PATH;
+		  goto trace01;
+		}
+	    }
+	  else
+	    {
+	      s1 = pool_elt_at_index (tsm->sessions, value1.value);
+	    }
+
+	  b1->flags |= VNET_BUFFER_F_IS_NATED;
+
+	  if (!is_output_feature)
+	    vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->out2in.fib_index;
+
+	  old_addr1 = ip1->src_address.as_u32;
+	  new_addr1 = ip1->src_address.as_u32 = s1->out2in.addr.as_u32;
+	  sum1 = ip1->checksum;
+	  sum1 = ip_csum_update (sum1, old_addr1, new_addr1, ip4_header_t,
+				 src_address);
+	  if (PREDICT_FALSE (is_twice_nat_session (s1)))
+	    sum1 = ip_csum_update (sum1, ip1->dst_address.as_u32,
+				   s1->ext_host_addr.as_u32, ip4_header_t,
+				   dst_address);
+	  ip1->checksum = ip_csum_fold (sum1);
+
+	  if (PREDICT_TRUE (proto1 == SNAT_PROTOCOL_TCP))
+	    {
+	      old_port1 = tcp1->src_port;
+	      new_port1 = tcp1->src_port = s1->out2in.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 (PREDICT_FALSE (is_twice_nat_session (s1)))
+		{
+		  sum1 = ip_csum_update (sum1, ip1->dst_address.as_u32,
+					 s1->ext_host_addr.as_u32,
+					 ip4_header_t, dst_address);
+		  sum1 = ip_csum_update (sum1, tcp1->dst_port,
+					 s1->ext_host_port, ip4_header_t,
+					 length);
+		  tcp1->dst_port = s1->ext_host_port;
+		  ip1->dst_address.as_u32 = s1->ext_host_addr.as_u32;
+		}
+	      tcp1->checksum = ip_csum_fold (sum1);
+	      mss_clamping (sm, tcp1, &sum1);
+	      if (nat44_set_tcp_session_state_i2o
+		  (sm, s1, tcp1, thread_index))
+		goto trace01;
+	    }
+	  else
+	    {
+	      udp1->src_port = s1->out2in.port;
+	      udp1->checksum = 0;
+	      if (PREDICT_FALSE (is_twice_nat_session (s1)))
+		{
+		  udp1->dst_port = s1->ext_host_port;
+		  ip1->dst_address.as_u32 = s1->ext_host_addr.as_u32;
+		}
+	    }
+
+	  /* Accounting */
+	  nat44_session_update_counters (s1, now,
+					 vlib_buffer_length_in_chain (vm,
+								      b1));
+
+	trace01:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b1->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      nat_in2out_ed_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 != NAT_IN2OUT_ED_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, iph_offset0 = 0, proto0,
+	    new_addr0, old_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;
+
+	  /* 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 = NAT_IN2OUT_ED_NEXT_LOOKUP;
+
+	  if (is_output_feature)
+	    iph_offset0 = vnet_buffer (b0)->ip.save_rewrite_length;
+
+	  ip0 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
+				  iph_offset0);
+
+	  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 = NAT_IN2OUT_ED_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_in2out_unknown_proto (sm, b0, ip0,
+						      rx_fib_index0,
+						      thread_index, now, vm,
+						      node);
+		  if (!s0)
+		    next0 = NAT_IN2OUT_ED_NEXT_DROP;
+		  goto trace0;
+		}
+
+	      if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
+		{
+		  next0 = icmp_in2out_ed_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))
+		{
+		  next0 = NAT_IN2OUT_ED_NEXT_SLOW_PATH;
+		  goto trace0;
+		}
+
+	      if (ip4_is_fragment (ip0))
+		{
+		  next0 = NAT_IN2OUT_ED_NEXT_REASS;
+		  goto trace0;
+		}
+
+	      if (is_output_feature)
+		{
+		  if (PREDICT_FALSE
+		      (nat_not_translate_output_feature_fwd
+		       (sm, ip0, thread_index, now, vm, b0)))
+		    goto trace0;
+		}
+
+	      if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
+		{
+		  next0 = NAT_IN2OUT_ED_NEXT_SLOW_PATH;
+		  goto trace0;
+		}
+	    }
+
+	  make_ed_kv (&kv0, &ip0->src_address, &ip0->dst_address,
+		      ip0->protocol, rx_fib_index0, udp0->src_port,
+		      udp0->dst_port);
+
+	  if (clib_bihash_search_16_8 (&tsm->in2out_ed, &kv0, &value0))
+	    {
+	      if (is_slow_path)
+		{
+		  if (is_output_feature)
+		    {
+		      if (PREDICT_FALSE
+			  (nat44_ed_not_translate_output_feature
+			   (sm, ip0, ip0->protocol, udp0->src_port,
+			    udp0->dst_port, thread_index, sw_if_index0,
+			    vnet_buffer (b0)->sw_if_index[VLIB_TX])))
+			goto trace0;
+		    }
+		  else
+		    {
+		      if (PREDICT_FALSE (nat44_ed_not_translate (sm, node,
+								 sw_if_index0,
+								 ip0, proto0,
+								 rx_fib_index0,
+								 thread_index)))
+			goto trace0;
+		    }
+
+		  next0 =
+		    slow_path_ed (sm, b0, rx_fib_index0, &kv0, &s0, node,
+				  next0, thread_index, now);
+
+		  if (PREDICT_FALSE (next0 == NAT_IN2OUT_ED_NEXT_DROP))
+		    goto trace0;
+		}
+	      else
+		{
+		  next0 = NAT_IN2OUT_ED_NEXT_SLOW_PATH;
+		  goto trace0;
+		}
+	    }
+	  else
+	    {
+	      s0 = pool_elt_at_index (tsm->sessions, value0.value);
+	    }
+
+	  b0->flags |= VNET_BUFFER_F_IS_NATED;
+
+	  if (!is_output_feature)
+	    vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
+
+	  old_addr0 = ip0->src_address.as_u32;
+	  new_addr0 = ip0->src_address.as_u32 = s0->out2in.addr.as_u32;
+	  sum0 = ip0->checksum;
+	  sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+				 src_address);
+	  if (PREDICT_FALSE (is_twice_nat_session (s0)))
+	    sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
+				   s0->ext_host_addr.as_u32, ip4_header_t,
+				   dst_address);
+	  ip0->checksum = ip_csum_fold (sum0);
+
+	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
+	    {
+	      old_port0 = tcp0->src_port;
+	      new_port0 = tcp0->src_port = s0->out2in.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 (PREDICT_FALSE (is_twice_nat_session (s0)))
+		{
+		  sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
+					 s0->ext_host_addr.as_u32,
+					 ip4_header_t, dst_address);
+		  sum0 = ip_csum_update (sum0, tcp0->dst_port,
+					 s0->ext_host_port, ip4_header_t,
+					 length);
+		  tcp0->dst_port = s0->ext_host_port;
+		  ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
+		}
+	      mss_clamping (sm, tcp0, &sum0);
+	      tcp0->checksum = ip_csum_fold (sum0);
+	      if (nat44_set_tcp_session_state_i2o
+		  (sm, s0, tcp0, thread_index))
+		goto trace0;
+	    }
+	  else
+	    {
+	      udp0->src_port = s0->out2in.port;
+	      udp0->checksum = 0;
+	      if (PREDICT_FALSE (is_twice_nat_session (s0)))
+		{
+		  udp0->dst_port = s0->ext_host_port;
+		  ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
+		}
+	    }
+
+	  /* Accounting */
+	  nat44_session_update_counters (s0, now,
+					 vlib_buffer_length_in_chain (vm,
+								      b0));
+
+	trace0:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      nat_in2out_ed_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 != NAT_IN2OUT_ED_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,
+			       NAT_IN2OUT_ED_ERROR_IN2OUT_PACKETS,
+			       pkts_processed);
+  return frame->n_vectors;
+}
+
+static uword
+nat44_ed_in2out_fast_path_fn (vlib_main_t * vm,
+			      vlib_node_runtime_t * node,
+			      vlib_frame_t * frame)
+{
+  return nat44_ed_in2out_node_fn_inline (vm, node, frame, 0, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_in2out_node) = {
+  .function = nat44_ed_in2out_fast_path_fn,
+  .name = "nat44-ed-in2out",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat_in2out_ed_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat_in2out_ed_error_strings),
+  .error_strings = nat_in2out_ed_error_strings,
+  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .n_next_nodes = NAT_IN2OUT_ED_N_NEXT,
+  .next_nodes = {
+    [NAT_IN2OUT_ED_NEXT_DROP] = "error-drop",
+    [NAT_IN2OUT_ED_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT_IN2OUT_ED_NEXT_SLOW_PATH] = "nat44-ed-in2out-slowpath",
+    [NAT_IN2OUT_ED_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT_IN2OUT_ED_NEXT_REASS] = "nat44-ed-in2out-reass",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_in2out_node,
+			      nat44_ed_in2out_fast_path_fn);
+
+static uword
+nat44_ed_in2out_output_fast_path_fn (vlib_main_t * vm,
+				     vlib_node_runtime_t * node,
+				     vlib_frame_t * frame)
+{
+  return nat44_ed_in2out_node_fn_inline (vm, node, frame, 0, 1);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_in2out_output_node) = {
+  .function = nat44_ed_in2out_output_fast_path_fn,
+  .name = "nat44-ed-in2out-output",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat_in2out_ed_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat_in2out_ed_error_strings),
+  .error_strings = nat_in2out_ed_error_strings,
+  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .n_next_nodes = NAT_IN2OUT_ED_N_NEXT,
+  .next_nodes = {
+    [NAT_IN2OUT_ED_NEXT_DROP] = "error-drop",
+    [NAT_IN2OUT_ED_NEXT_LOOKUP] = "interface-output",
+    [NAT_IN2OUT_ED_NEXT_SLOW_PATH] = "nat44-ed-in2out-output-slowpath",
+    [NAT_IN2OUT_ED_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT_IN2OUT_ED_NEXT_REASS] = "nat44-ed-in2out-reass-output",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_in2out_output_node,
+			      nat44_ed_in2out_output_fast_path_fn);
+
+static uword
+nat44_ed_in2out_slow_path_fn (vlib_main_t * vm,
+			      vlib_node_runtime_t * node,
+			      vlib_frame_t * frame)
+{
+  return nat44_ed_in2out_node_fn_inline (vm, node, frame, 1, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_in2out_slowpath_node) = {
+  .function = nat44_ed_in2out_slow_path_fn,
+  .name = "nat44-ed-in2out-slowpath",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat_in2out_ed_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat_in2out_ed_error_strings),
+  .error_strings = nat_in2out_ed_error_strings,
+  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .n_next_nodes = NAT_IN2OUT_ED_N_NEXT,
+  .next_nodes = {
+    [NAT_IN2OUT_ED_NEXT_DROP] = "error-drop",
+    [NAT_IN2OUT_ED_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT_IN2OUT_ED_NEXT_SLOW_PATH] = "nat44-ed-in2out-slowpath",
+    [NAT_IN2OUT_ED_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT_IN2OUT_ED_NEXT_REASS] = "nat44-ed-in2out-reass",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_in2out_slowpath_node,
+			      nat44_ed_in2out_slow_path_fn);
+
+static uword
+nat44_ed_in2out_output_slow_path_fn (vlib_main_t * vm,
+				     vlib_node_runtime_t * node,
+				     vlib_frame_t * frame)
+{
+  return nat44_ed_in2out_node_fn_inline (vm, node, frame, 1, 1);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_in2out_output_slowpath_node) = {
+  .function = nat44_ed_in2out_output_slow_path_fn,
+  .name = "nat44-ed-in2out-output-slowpath",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat_in2out_ed_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat_in2out_ed_error_strings),
+  .error_strings = nat_in2out_ed_error_strings,
+  .runtime_data_bytes = sizeof (snat_runtime_t),
+  .n_next_nodes = NAT_IN2OUT_ED_N_NEXT,
+  .next_nodes = {
+    [NAT_IN2OUT_ED_NEXT_DROP] = "error-drop",
+    [NAT_IN2OUT_ED_NEXT_LOOKUP] = "interface-output",
+    [NAT_IN2OUT_ED_NEXT_SLOW_PATH] = "nat44-ed-in2out-output-slowpath",
+    [NAT_IN2OUT_ED_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT_IN2OUT_ED_NEXT_REASS] = "nat44-ed-in2out-reass",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_in2out_output_slowpath_node,
+			      nat44_ed_in2out_output_slow_path_fn);
+
+static inline uword
+nat44_ed_in2out_reass_node_fn_inline (vlib_main_t * vm,
+				      vlib_node_runtime_t * node,
+				      vlib_frame_t * frame,
+				      int is_output_feature)
+{
+  u32 n_left_from, *from, *to_next;
+  nat_in2out_ed_next_t next_index;
+  u32 pkts_processed = 0;
+  snat_main_t *sm = &snat_main;
+  f64 now = vlib_time_now (vm);
+  u32 thread_index = vm->thread_index;
+  snat_main_per_thread_data_t *per_thread_data =
+    &sm->per_thread_data[thread_index];
+  u32 *fragments_to_drop = 0;
+  u32 *fragments_to_loopback = 0;
+
+  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 > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0, sw_if_index0, proto0, rx_fib_index0, new_addr0, old_addr0;
+	  u32 iph_offset0 = 0;
+	  vlib_buffer_t *b0;
+	  u32 next0;
+	  u8 cached0 = 0;
+	  ip4_header_t *ip0 = 0;
+	  nat_reass_ip4_t *reass0;
+	  udp_header_t *udp0;
+	  tcp_header_t *tcp0;
+	  icmp46_header_t *icmp0;
+	  clib_bihash_kv_16_8_t kv0, value0;
+	  snat_session_t *s0 = 0;
+	  u16 old_port0, new_port0;
+	  ip_csum_t sum0;
+
+	  /* 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 = NAT_IN2OUT_ED_NEXT_LOOKUP;
+
+	  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 (nat_reass_is_drop_frag (0)))
+	    {
+	      next0 = NAT_IN2OUT_ED_NEXT_DROP;
+	      b0->error = node->errors[NAT_IN2OUT_ED_ERROR_DROP_FRAGMENT];
+	      goto trace0;
+	    }
+
+	  if (is_output_feature)
+	    iph_offset0 = vnet_buffer (b0)->ip.save_rewrite_length;
+
+	  ip0 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
+				  iph_offset0);
+
+	  udp0 = ip4_next_header (ip0);
+	  tcp0 = (tcp_header_t *) udp0;
+	  icmp0 = (icmp46_header_t *) udp0;
+	  proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+	  reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
+						 ip0->dst_address,
+						 ip0->fragment_id,
+						 ip0->protocol,
+						 1, &fragments_to_drop);
+
+	  if (PREDICT_FALSE (!reass0))
+	    {
+	      next0 = NAT_IN2OUT_ED_NEXT_DROP;
+	      b0->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_REASS];
+	      nat_log_notice ("maximum reassemblies exceeded");
+	      goto trace0;
+	    }
+
+	  if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
+	    {
+	      if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
+		{
+		  if (is_output_feature)
+		    {
+		      if (PREDICT_FALSE
+			  (nat_not_translate_output_feature_fwd
+			   (sm, ip0, thread_index, now, vm, b0)))
+			reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
+		      goto trace0;
+		    }
+
+		  next0 = icmp_in2out_ed_slow_path
+		    (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
+		     next0, now, thread_index, &s0);
+
+		  if (PREDICT_TRUE (next0 != NAT_IN2OUT_ED_NEXT_DROP))
+		    {
+		      if (s0)
+			reass0->sess_index = s0 - per_thread_data->sessions;
+		      else
+			reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
+		      nat_ip4_reass_get_frags (reass0,
+					       &fragments_to_loopback);
+		    }
+
+		  goto trace0;
+		}
+
+	      make_ed_kv (&kv0, &ip0->src_address, &ip0->dst_address,
+			  ip0->protocol, rx_fib_index0, udp0->src_port,
+			  udp0->dst_port);
+
+	      if (clib_bihash_search_16_8
+		  (&per_thread_data->in2out_ed, &kv0, &value0))
+		{
+		  if (is_output_feature)
+		    {
+		      if (PREDICT_FALSE
+			  (nat44_ed_not_translate_output_feature
+			   (sm, ip0, ip0->protocol, udp0->src_port,
+			    udp0->dst_port, thread_index, sw_if_index0,
+			    vnet_buffer (b0)->sw_if_index[VLIB_TX])))
+			{
+			  reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
+			  nat_ip4_reass_get_frags (reass0,
+						   &fragments_to_loopback);
+			  goto trace0;
+			}
+		    }
+		  else
+		    {
+		      if (PREDICT_FALSE (nat44_ed_not_translate (sm, node,
+								 sw_if_index0,
+								 ip0, proto0,
+								 rx_fib_index0,
+								 thread_index)))
+			{
+			  reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
+			  nat_ip4_reass_get_frags (reass0,
+						   &fragments_to_loopback);
+			  goto trace0;
+			}
+		    }
+
+		  next0 = slow_path_ed (sm, b0, rx_fib_index0, &kv0,
+					&s0, node, next0, thread_index, now);
+
+		  if (PREDICT_FALSE (next0 == NAT_IN2OUT_ED_NEXT_DROP))
+		    goto trace0;
+
+		  reass0->sess_index = s0 - per_thread_data->sessions;
+		}
+	      else
+		{
+		  s0 = pool_elt_at_index (per_thread_data->sessions,
+					  value0.value);
+		  reass0->sess_index = value0.value;
+		}
+	      nat_ip4_reass_get_frags (reass0, &fragments_to_loopback);
+	    }
+	  else
+	    {
+	      if (reass0->flags & NAT_REASS_FLAG_ED_DONT_TRANSLATE)
+		goto trace0;
+	      if (PREDICT_FALSE (reass0->sess_index == (u32) ~ 0))
+		{
+		  if (nat_ip4_reass_add_fragment
+		      (reass0, bi0, &fragments_to_drop))
+		    {
+		      b0->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_FRAG];
+		      nat_log_notice
+			("maximum fragments per reassembly exceeded");
+		      next0 = NAT_IN2OUT_ED_NEXT_DROP;
+		      goto trace0;
+		    }
+		  cached0 = 1;
+		  goto trace0;
+		}
+	      s0 = pool_elt_at_index (per_thread_data->sessions,
+				      reass0->sess_index);
+	    }
+
+	  old_addr0 = ip0->src_address.as_u32;
+	  ip0->src_address = s0->out2in.addr;
+	  new_addr0 = ip0->src_address.as_u32;
+	  if (!is_output_feature)
+	    vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
+
+	  sum0 = ip0->checksum;
+	  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+				 ip4_header_t,
+				 src_address /* changed member */ );
+	  if (PREDICT_FALSE (is_twice_nat_session (s0)))
+	    sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
+				   s0->ext_host_addr.as_u32, ip4_header_t,
+				   dst_address);
+	  ip0->checksum = ip_csum_fold (sum0);
+
+	  if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
+	    {
+	      if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
+		{
+		  old_port0 = tcp0->src_port;
+		  tcp0->src_port = s0->out2in.port;
+		  new_port0 = tcp0->src_port;
+
+		  sum0 = tcp0->checksum;
+		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+					 ip4_header_t,
+					 dst_address /* changed member */ );
+		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
+					 ip4_header_t /* cheat */ ,
+					 length /* changed member */ );
+		  if (PREDICT_FALSE (is_twice_nat_session (s0)))
+		    {
+		      sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
+					     s0->ext_host_addr.as_u32,
+					     ip4_header_t, dst_address);
+		      sum0 = ip_csum_update (sum0, tcp0->dst_port,
+					     s0->ext_host_port, ip4_header_t,
+					     length);
+		      tcp0->dst_port = s0->ext_host_port;
+		      ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
+		    }
+		  tcp0->checksum = ip_csum_fold (sum0);
+		}
+	      else
+		{
+		  old_port0 = udp0->src_port;
+		  udp0->src_port = s0->out2in.port;
+		  udp0->checksum = 0;
+		  if (PREDICT_FALSE (is_twice_nat_session (s0)))
+		    {
+		      udp0->dst_port = s0->ext_host_port;
+		      ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
+		    }
+		}
+	    }
+
+	  /* Hairpinning */
+	  if (PREDICT_TRUE (proto0 != SNAT_PROTOCOL_ICMP))
+	    nat44_reass_hairpinning (sm, b0, ip0, s0->out2in.port,
+				     s0->ext_host_port, proto0, 1);
+	  else
+	    snat_icmp_hairpinning (sm, b0, ip0, icmp0, 1);
+
+	  /* Accounting */
+	  nat44_session_update_counters (s0, now,
+					 vlib_buffer_length_in_chain (vm,
+								      b0));
+
+	trace0:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      nat44_reass_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->cached = cached0;
+	      t->sw_if_index = sw_if_index0;
+	      t->next_index = next0;
+	    }
+
+	  if (cached0)
+	    {
+	      n_left_to_next++;
+	      to_next--;
+	    }
+	  else
+	    {
+	      pkts_processed += next0 != NAT_IN2OUT_ED_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);
+	    }
+
+	  if (n_left_from == 0 && vec_len (fragments_to_loopback))
+	    {
+	      from = vlib_frame_vector_args (frame);
+	      u32 len = vec_len (fragments_to_loopback);
+	      if (len <= VLIB_FRAME_SIZE)
+		{
+		  clib_memcpy (from, fragments_to_loopback,
+			       sizeof (u32) * len);
+		  n_left_from = len;
+		  vec_reset_length (fragments_to_loopback);
+		}
+	      else
+		{
+		  clib_memcpy (from,
+			       fragments_to_loopback + (len -
+							VLIB_FRAME_SIZE),
+			       sizeof (u32) * VLIB_FRAME_SIZE);
+		  n_left_from = VLIB_FRAME_SIZE;
+		  _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
+		}
+	    }
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  vlib_node_increment_counter (vm, nat44_ed_in2out_reass_node.index,
+			       NAT_IN2OUT_ED_ERROR_IN2OUT_PACKETS,
+			       pkts_processed);
+
+  nat_send_all_to_node (vm, fragments_to_drop, node,
+			&node->errors[NAT_IN2OUT_ED_ERROR_DROP_FRAGMENT],
+			NAT_IN2OUT_ED_NEXT_DROP);
+
+  vec_free (fragments_to_drop);
+  vec_free (fragments_to_loopback);
+  return frame->n_vectors;
+}
+
+static uword
+nat44_ed_in2out_reass_node_fn (vlib_main_t * vm,
+			       vlib_node_runtime_t * node,
+			       vlib_frame_t * frame)
+{
+  return nat44_ed_in2out_reass_node_fn_inline (vm, node, frame, 0);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_in2out_reass_node) = {
+  .function = nat44_ed_in2out_reass_node_fn,
+  .name = "nat44-ed-in2out-reass",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat44_reass_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat_in2out_ed_error_strings),
+  .error_strings = nat_in2out_ed_error_strings,
+  .n_next_nodes = NAT_IN2OUT_ED_N_NEXT,
+  .next_nodes = {
+    [NAT_IN2OUT_ED_NEXT_DROP] = "error-drop",
+    [NAT_IN2OUT_ED_NEXT_LOOKUP] = "ip4-lookup",
+    [NAT_IN2OUT_ED_NEXT_SLOW_PATH] = "nat44-in2out-slowpath",
+    [NAT_IN2OUT_ED_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT_IN2OUT_ED_NEXT_REASS] = "nat44-ed-in2out-reass",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_in2out_reass_node,
+			      nat44_ed_in2out_reass_node_fn);
+
+static uword
+nat44_ed_in2out_reass_output_node_fn (vlib_main_t * vm,
+				      vlib_node_runtime_t * node,
+				      vlib_frame_t * frame)
+{
+  return nat44_ed_in2out_reass_node_fn_inline (vm, node, frame, 1);
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (nat44_ed_in2out_reass_output_node) = {
+  .function = nat44_ed_in2out_reass_output_node_fn,
+  .name = "nat44-ed-in2out-reass-output",
+  .vector_size = sizeof (u32),
+  .format_trace = format_nat44_reass_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (nat_in2out_ed_error_strings),
+  .error_strings = nat_in2out_ed_error_strings,
+  .n_next_nodes = NAT_IN2OUT_ED_N_NEXT,
+  .next_nodes = {
+    [NAT_IN2OUT_ED_NEXT_DROP] = "error-drop",
+    [NAT_IN2OUT_ED_NEXT_LOOKUP] = "interface-output",
+    [NAT_IN2OUT_ED_NEXT_SLOW_PATH] = "nat44-in2out-slowpath",
+    [NAT_IN2OUT_ED_NEXT_ICMP_ERROR] = "ip4-icmp-error",
+    [NAT_IN2OUT_ED_NEXT_REASS] = "nat44-ed-in2out-reass",
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (nat44_ed_in2out_reass_output_node,
+			      nat44_ed_in2out_reass_output_node_fn);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */