path: root/src/plugins/nat/in2out_ed.c

/*
 * 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 <vnet/udp/udp.h>
#include <vppinfra/error.h>
#include <nat/nat.h>
#include <nat/nat_ipfix_logging.h>
#include <nat/nat_inlines.h>
#include <nat/nat44/inlines.h>
#include <nat/nat_syslog.h>
#include <nat/nat_ha.h>

static char *nat_in2out_ed_error_strings[] = {
#define _(sym,string) string,
  foreach_nat_in2out_ed_error
#undef _
};

typedef struct
{
  u32 sw_if_index;
  u32 next_index;
  u32 session_index;
  u32 is_slow_path;
} nat_in2out_ed_trace_t;

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;
}

#ifndef CLIB_MARCH_VARIANT
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_elog_warn ("out2in_ed key del failed");

      if (snat_is_unk_proto_session (s))
	goto delete;

      snat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
					   s->in2out.addr.as_u32,
					   s->out2in.addr.as_u32,
					   s->in2out.protocol,
					   s->in2out.port,
					   s->out2in.port,
					   s->in2out.fib_index);

      nat_syslog_nat44_sdel (s->user_index, s->in2out.fib_index,
			     &s->in2out.addr, s->in2out.port,
			     &s->ext_host_nat_addr, s->ext_host_nat_port,
			     &s->out2in.addr, s->out2in.port,
			     &s->ext_host_addr, s->ext_host_port,
			     s->in2out.protocol, is_twice_nat_session (s));

      nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
		   s->ext_host_port, s->out2in.protocol, s->out2in.fib_index,
		   ctx->thread_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;
}
#endif

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_NEXT_DROP && s0))
    {
      /* Accounting */
      nat44_session_update_counters (s0, now,
				     vlib_buffer_length_in_chain
				     (sm->vlib_main, b0), thread_index);
      /* Per-user LRU list maintenance */
      nat44_session_update_lru (sm, s0, thread_index);
    }
  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 = 0;
  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;
  u8 identity_nat;
  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;

  u32 cleared = 0;

  if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
    {
      if (PREDICT_FALSE
	  (!(cleared = nat44_users_cleanup (thread_index, now))))
	{
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
	  nat_ipfix_logging_max_sessions (thread_index, sm->max_translations);
	  nat_elog_notice ("maximum sessions exceeded");
	  return NAT_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, &identity_nat))
    {
      /* 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))
	{
	  if (cleared || !nat44_out_of_ports_cleanup (thread_index, now) ||
	      snat_alloc_outside_address_and_port (sm->addresses,
						   rx_fib_index, thread_index,
						   &key1, sm->port_per_thread,
						   tsm->snat_thread_index))
	    {
	      nat_elog_notice ("addresses exhausted");
	      b->error = node->errors[NAT_IN2OUT_ED_ERROR_OUT_OF_PORTS];
	      return NAT_NEXT_DROP;
	    }
	}
    }
  else
    {
      if (PREDICT_FALSE (identity_nat))
	{
	  *sessionp = s;
	  return next;
	}
      is_sm = 1;
    }

  if (PREDICT_TRUE (proto == SNAT_PROTOCOL_TCP))
    {
      if (PREDICT_FALSE
	  (!tcp_flags_is_init
	   (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags)))
	{
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_NON_SYN];
	  if (!is_sm)
	    snat_free_outside_address_and_port (sm->addresses,
						thread_index, &key1);
	  return NAT_NEXT_DROP;
	}
    }

  u = nat_user_get_or_create (sm, &key->l_addr, rx_fib_index, thread_index);
  if (!u)
    {
      nat_elog_warn ("create NAT user failed");
      if (!is_sm)
	snat_free_outside_address_and_port (sm->addresses,
					    thread_index, &key1);
      b->error = node->errors[NAT_IN2OUT_ED_ERROR_CANNOT_CREATE_USER];
      return NAT_NEXT_DROP;
    }

  s = nat_ed_session_alloc (sm, u, thread_index, now);
  if (!s)
    {
      nat44_delete_user_with_no_session (sm, u, thread_index);
      nat_elog_warn ("create NAT session failed");
      if (!is_sm)
	snat_free_outside_address_and_port (sm->addresses,
					    thread_index, &key1);
      b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_USER_SESS_EXCEEDED];
      return NAT_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_elog_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_elog_notice ("out2in-ed key add failed");

  *sessionp = s;

  /* log NAT event */
  snat_ipfix_logging_nat44_ses_create (thread_index,
				       s->in2out.addr.as_u32,
				       s->out2in.addr.as_u32,
				       s->in2out.protocol,
				       s->in2out.port,
				       s->out2in.port, s->in2out.fib_index);

  nat_syslog_nat44_sadd (s->user_index, s->in2out.fib_index,
			 &s->in2out.addr, s->in2out.port,
			 &s->ext_host_nat_addr, s->ext_host_nat_port,
			 &s->out2in.addr, s->out2in.port,
			 &s->ext_host_addr, s->ext_host_port,
			 s->in2out.protocol, 0);

  nat_ha_sadd (&s->in2out.addr, s->in2out.port, &s->out2in.addr,
	       s->out2in.port, &s->ext_host_addr, s->ext_host_port,
	       &s->ext_host_nat_addr, s->ext_host_nat_port,
	       s->in2out.protocol, s->in2out.fib_index, s->flags,
	       thread_index, 0);

  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, 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;
  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 (get_icmp_i2o_ed_key (b, 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)
    {
      make_ed_kv (&kv, &ip->src_address, &ip->dst_address, ip->protocol, 0,
		  vnet_buffer (b)->ip.reass.l4_src_port,
		  vnet_buffer (b)->ip.reass.l4_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)
	    {
	      if (nat44_set_tcp_session_state_i2o
		  (sm, now, s, b, thread_index))
		return 1;
	    }
	  /* Accounting */
	  nat44_session_update_counters (s, now,
					 vlib_buffer_length_in_chain (vm, b),
					 thread_index);
	  /* Per-user LRU list maintenance */
	  nat44_session_update_lru (sm, s, thread_index);
	  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))
    {
      s = pool_elt_at_index (tsm->sessions, value.value);
      if (nat44_is_ses_closed (s))
	{
	  nat_free_session_data (sm, s, thread_index, 0);
	  nat44_delete_session (sm, s, thread_index);
	}
      else
	s->flags |= SNAT_SESSION_FLAG_OUTPUT_FEATURE;
      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;
}

#ifndef CLIB_MARCH_VARIANT
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)
{
  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];

  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 = get_icmp_i2o_ed_key (b, ip, &key);
  if (err != 0)
    {
      b->error = node->errors[err];
      next = NAT_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_type_is_error_message
	   (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags)))
	{
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_BAD_ICMP_TYPE];
	  next = NAT_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_NEXT_DROP))
	goto out;

      if (!s)
	{
	  dont_translate = 1;
	  goto out;
	}
    }
  else
    {
      if (PREDICT_FALSE
	  (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags !=
	   ICMP4_echo_request
	   && vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags !=
	   ICMP4_echo_reply
	   && !icmp_type_is_error_message (vnet_buffer (b)->ip.
					   reass.icmp_type_or_tcp_flags)))
	{
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_BAD_ICMP_TYPE];
	  next = NAT_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;
}
#endif

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 (nat44_maximum_sessions_exceeded (sm, thread_index)))
	{
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
	  nat_ipfix_logging_max_sessions (thread_index, sm->max_translations);
	  nat_elog_notice ("maximum sessions exceeded");
	  return 0;
	}

      u = nat_user_get_or_create (sm, &ip->src_address, rx_fib_index,
				  thread_index);
      if (!u)
	{
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_CANNOT_CREATE_USER];
	  nat_elog_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, now);
      if (!s)
	{
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_USER_SESS_EXCEEDED];
	  nat44_delete_user_with_no_session (sm, u, thread_index);
	  nat_elog_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_elog_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_elog_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),
				 thread_index);
  /* Per-user LRU list maintenance */
  nat44_session_update_lru (sm, s, thread_index);

  /* 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_fast_path_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, pkts_processed = 0, stats_node_index;
  nat_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];
  u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets =
    0, def_slow;
  u32 tcp_closed_drops = 0;

  def_slow = is_output_feature ? NAT_NEXT_IN2OUT_ED_OUTPUT_SLOW_PATH :
    NAT_NEXT_IN2OUT_ED_SLOW_PATH;

  stats_node_index = sm->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 > 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;
	  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);

	  if (is_output_feature)
	    {
	      vnet_feature_next (&nat_buffer_opaque (b0)->arc_next, b0);
	      iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;
	    }

	  next0 = nat_buffer_opaque (b0)->arc_next;

	  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_NEXT_ICMP_ERROR;
	      goto trace0;
	    }

	  udp0 = ip4_next_header (ip0);
	  tcp0 = (tcp_header_t *) udp0;
	  proto0 = ip_proto_to_snat_proto (ip0->protocol);

	  if (PREDICT_FALSE (proto0 == ~0))
	    {
	      next0 = def_slow;
	      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 = def_slow;
	      goto trace0;
	    }

	  make_ed_kv (&kv0, &ip0->src_address, &ip0->dst_address,
		      ip0->protocol, rx_fib_index0,
		      vnet_buffer (b0)->ip.reass.l4_src_port,
		      vnet_buffer (b0)->ip.reass.l4_dst_port);

	  // lookup for session
	  if (clib_bihash_search_16_8 (&tsm->in2out_ed, &kv0, &value0))
	    {
	      // session does not exist go slow path
	      next0 = def_slow;
	      goto trace0;
	    }
	  s0 = pool_elt_at_index (tsm->sessions, value0.value);

	  if (s0->tcp_close_timestamp)
	    {
	      if (now >= s0->tcp_close_timestamp)
		{
		  // session is closed, go slow path
		  next0 = def_slow;
		}
	      else
		{
		  // session in transitory timeout, drop
		  ++tcp_closed_drops;
		  b0->error = node->errors[NAT_IN2OUT_ED_ERROR_TCP_CLOSED];
		  next0 = NAT_NEXT_DROP;
		}
	      goto trace0;
	    }

	  // drop if session expired
	  u64 sess_timeout_time;
	  sess_timeout_time = s0->last_heard +
	    (f64) nat44_session_get_timeout (sm, s0);
	  if (now >= sess_timeout_time)
	    {
	      // delete session
	      nat_free_session_data (sm, s0, thread_index, 0);
	      nat44_delete_session (sm, s0, thread_index);

	      // session no longer exists, go slow path
	      next0 = def_slow;
	      goto trace0;
	    }

	  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);

	  old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;

	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
	    {
	      if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
		{
		  new_port0 = udp0->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,
					vnet_buffer (b0)->ip.
					reass.l4_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);
		}
	      tcp_packets++;
	      if (nat44_set_tcp_session_state_i2o
		  (sm, now, s0, b0, thread_index))
		goto trace0;
	    }
	  else if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment
		   && udp0->checksum)
	    {
	      new_port0 = udp0->src_port = s0->out2in.port;
	      sum0 = udp0->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,
				    vnet_buffer (b0)->ip.reass.l4_dst_port,
				    s0->ext_host_port, ip4_header_t, length);
		  udp0->dst_port = s0->ext_host_port;
		  ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
		}
	      udp0->checksum = ip_csum_fold (sum0);
	      udp_packets++;
	    }
	  else
	    {
	      if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
		{
		  new_port0 = udp0->src_port = s0->out2in.port;
		  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;
		    }
		  udp_packets++;
		}
	    }

	  /* Accounting */
	  nat44_session_update_counters (s0, now,
					 vlib_buffer_length_in_chain
					 (vm, b0), thread_index);
	  /* 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)))
	    {
	      nat_in2out_ed_trace_t *t =
		vlib_add_trace (vm, node, b0, sizeof (*t));
	      t->sw_if_index = sw_if_index0;
	      t->next_index = next0;
	      t->is_slow_path = 0;

	      if (s0)
		t->session_index = s0 - tsm->sessions;
	      else
		t->session_index = ~0;
	    }

	  pkts_processed += next0 == nat_buffer_opaque (b0)->arc_next;
	  /* 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);
  vlib_node_increment_counter (vm, stats_node_index,
			       NAT_IN2OUT_ED_ERROR_TCP_PACKETS, tcp_packets);
  vlib_node_increment_counter (vm, stats_node_index,
			       NAT_IN2OUT_ED_ERROR_UDP_PACKETS, udp_packets);
  vlib_node_increment_counter (vm, stats_node_index,
			       NAT_IN2OUT_ED_ERROR_ICMP_PACKETS,
			       icmp_packets);
  vlib_node_increment_counter (vm, stats_node_index,
			       NAT_IN2OUT_ED_ERROR_OTHER_PACKETS,
			       other_packets);
  return frame->n_vectors;
}

static inline uword
nat44_ed_in2out_slow_path_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, pkts_processed = 0, stats_node_index;
  nat_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];
  u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets = 0;

  stats_node_index = sm->ed_in2out_slowpath_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 > 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);

	  if (is_output_feature)
	    iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;

	  next0 = nat_buffer_opaque (b0)->arc_next;

	  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_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 (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_NEXT_DROP;

	      other_packets++;
	      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);
	      icmp_packets++;
	      goto trace0;
	    }

	  // move down
	  make_ed_kv (&kv0, &ip0->src_address, &ip0->dst_address,
		      ip0->protocol, rx_fib_index0,
		      vnet_buffer (b0)->ip.reass.l4_src_port,
		      vnet_buffer (b0)->ip.reass.l4_dst_port);

	  if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv0, &value0))
	    {
	      s0 = pool_elt_at_index (tsm->sessions, value0.value);

	      if (s0->tcp_close_timestamp && now >= s0->tcp_close_timestamp)
		{
		  nat_free_session_data (sm, s0, thread_index, 0);
		  nat44_delete_session (sm, s0, thread_index);
		  s0 = NULL;
		}
	    }

	  if (!s0)
	    {
	      if (is_output_feature)
		{
		  if (PREDICT_FALSE
		      (nat44_ed_not_translate_output_feature
		       (sm, ip0, ip0->protocol,
			vnet_buffer (b0)->ip.reass.l4_src_port,
			vnet_buffer (b0)->ip.reass.l4_dst_port,
			thread_index, sw_if_index0,
			vnet_buffer (b0)->sw_if_index[VLIB_TX])))
		    goto trace0;

		  /*
		   * 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
		       && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
			   clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_server))
		       && ip0->dst_address.as_u32 == 0xffffffff))
		    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_NEXT_DROP))
		goto trace0;

	      if (PREDICT_FALSE (!s0))
		goto trace0;

	    }

	  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);

	  old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;

	  if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
	    {
	      if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
		{
		  new_port0 = udp0->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,
					vnet_buffer (b0)->ip.
					reass.l4_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);
		}
	      tcp_packets++;
	      if (nat44_set_tcp_session_state_i2o
		  (sm, now, s0, b0, thread_index))
		goto trace0;
	    }
	  else if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment
		   && udp0->checksum)
	    {
	      new_port0 = udp0->src_port = s0->out2in.port;
	      sum0 = udp0->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,
				    vnet_buffer (b0)->ip.reass.l4_dst_port,
				    s0->ext_host_port, ip4_header_t, length);
		  udp0->dst_port = s0->ext_host_port;
		  ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
		}
	      udp0->checksum = ip_csum_fold (sum0);
	      udp_packets++;
	    }
	  else
	    {
	      if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
		{
		  new_port0 = udp0->src_port = s0->out2in.port;
		  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;
		    }
		  udp_packets++;
		}
	    }

	  /* Accounting */
	  nat44_session_update_counters (s0, now,
					 vlib_buffer_length_in_chain
					 (vm, b0), thread_index);
	  /* 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)))
	    {
	      nat_in2out_ed_trace_t *t =
		vlib_add_trace (vm, node, b0, sizeof (*t));
	      t->sw_if_index = sw_if_index0;
	      t->next_index = next0;
	      t->is_slow_path = 1;

	      if (s0)
		t->session_index = s0 - tsm->sessions;
	      else
		t->session_index = ~0;
	    }

	  pkts_processed += next0 == nat_buffer_opaque (b0)->arc_next;

	  /* 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);
  vlib_node_increment_counter (vm, stats_node_index,
			       NAT_IN2OUT_ED_ERROR_TCP_PACKETS, tcp_packets);
  vlib_node_increment_counter (vm, stats_node_index,
			       NAT_IN2OUT_ED_ERROR_UDP_PACKETS, udp_packets);
  vlib_node_increment_counter (vm, stats_node_index,
			       NAT_IN2OUT_ED_ERROR_ICMP_PACKETS,
			       icmp_packets);
  vlib_node_increment_counter (vm, stats_node_index,
			       NAT_IN2OUT_ED_ERROR_OTHER_PACKETS,
			       other_packets);
  return frame->n_vectors;
}

VLIB_NODE_FN (nat44_ed_in2out_node) (vlib_main_t * vm,
				     vlib_node_runtime_t * node,
				     vlib_frame_t * frame)
{
  return nat44_ed_in2out_fast_path_node_fn_inline (vm, node, frame, 0);
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (nat44_ed_in2out_node) = {
  .name = "nat44-ed-in2out",
  .vector_size = sizeof (u32),
  .sibling_of = "nat-default",
  .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),
};
/* *INDENT-ON* */

VLIB_NODE_FN (nat44_ed_in2out_output_node) (vlib_main_t * vm,
					    vlib_node_runtime_t * node,
					    vlib_frame_t * frame)
{
  return nat44_ed_in2out_fast_path_node_fn_inline (vm, node, frame, 1);
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (nat44_ed_in2out_output_node) = {
  .name = "nat44-ed-in2out-output",
  .vector_size = sizeof (u32),
  .sibling_of = "nat-default",
  .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),
};
/* *INDENT-ON* */

VLIB_NODE_FN (nat44_ed_in2out_slowpath_node) (vlib_main_t * vm,
					      vlib_node_runtime_t *
					      node, vlib_frame_t * frame)
{
  return nat44_ed_in2out_slow_path_node_fn_inline (vm, node, frame, 0);
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (nat44_ed_in2out_slowpath_node) = {
  .name = "nat44-ed-in2out-slowpath",
  .vector_size = sizeof (u32),
  .sibling_of = "nat-default",
  .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),
};
/* *INDENT-ON* */

VLIB_NODE_FN (nat44_ed_in2out_output_slowpath_node) (vlib_main_t * vm,
						     vlib_node_runtime_t
						     * node,
						     vlib_frame_t * frame)
{
  return nat44_ed_in2out_slow_path_node_fn_inline (vm, node, frame, 1);
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (nat44_ed_in2out_output_slowpath_node) = {
  .name = "nat44-ed-in2out-output-slowpath",
  .vector_size = sizeof (u32),
  .sibling_of = "nat-default",
  .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),
};
/* *INDENT-ON* */

static u8 *
format_nat_pre_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_pre_trace_t *t = va_arg (*args, nat_pre_trace_t *);
  return format (s, "in2out next_index %d", t->next_index);
}

VLIB_NODE_FN (nat_pre_in2out_node)
  (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  return nat_pre_node_fn_inline (vm, node, frame,
				 NAT_NEXT_IN2OUT_ED_FAST_PATH);
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (nat_pre_in2out_node) = {
  .name = "nat-pre-in2out",
  .vector_size = sizeof (u32),
  .sibling_of = "nat-default",
  .format_trace = format_nat_pre_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = 0,
};
/* *INDENT-ON* */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */