/*
 * Copyright (c) 2015 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.
 */
/*
  Copyright (c) 2001, 2002, 2003, 2005 Eliot Dresselhaus

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:

  The above copyright notice and this permission notice shall be
  included in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#ifndef included_clib_bitmap_h
#define included_clib_bitmap_h

/** \file
    Bitmaps built as vectors of machine words
*/

#include <vppinfra/vec.h>
#include <vppinfra/random.h>
#include <vppinfra/error.h>
#include <vppinfra/bitops.h>	/* for count_set_bits */

typedef uword clib_bitmap_t;

/** predicate function; is an entire bitmap empty?
    @param ai - pointer to a bitmap
    @returns 1 if the entire bitmap is zero, 0 otherwise
*/
always_inline uword
clib_bitmap_is_zero (uword * ai)
{
  uword i;
  for (i = 0; i < vec_len (ai); i++)
    if (ai[i] != 0)
      return 0;
  return 1;
}

/** predicate function; are two bitmaps equal?
    @param a - pointer to a bitmap
    @param b - pointer to a bitmap
    @returns 1 if the bitmaps are equal, 0 otherwise
*/
always_inline uword
clib_bitmap_is_equal (uword * a, uword * b)
{
  uword i;
  if (vec_len (a) != vec_len (b))
    return 0;
  for (i = 0; i < vec_len (a); i++)
    if (a[i] != b[i])
      return 0;
  return 1;
}

/** Duplicate a bitmap
    @param v - pointer to a bitmap
    @returns a duplicate of the bitmap
*/
#define clib_bitmap_dup(v) vec_dup(v)

/** Free a bitmap
    @param v - pointer to the bitmap to free
*/
#define clib_bitmap_free(v) vec_free(v)

/** Number of bytes in a bitmap
    @param v - pointer to the bitmap
*/
#define clib_bitmap_bytes(v) vec_bytes(v)

/** Clear a bitmap
    @param v - pointer to the bitmap to clear
*/
#define clib_bitmap_zero(v) vec_zero(v)

/** Allocate a bitmap with the supplied number of bits
    @param [out] v - the resulting bitmap
    @param n_bits - the required number of bits
*/

#define clib_bitmap_alloc(v,n_bits) \
  v = vec_new (uword, ((n_bits) + BITS (uword) - 1) / BITS (uword))

#define clib_bitmap_vec_validate(v,i) vec_validate_aligned((v),(i),sizeof(uword))

/* Make sure that a bitmap is at least n_bits in size */
#define clib_bitmap_validate(v,n_bits) \
  clib_bitmap_vec_validate ((v), ((n_bits) - 1) / BITS (uword))

/* low-level routine to remove trailing zeros from a bitmap */
always_inline uword *
_clib_bitmap_remove_trailing_zeros (uword * a)
{
  word i;
  if (a)
    {
      for (i = _vec_len (a) - 1; i >= 0; i--)
	if (a[i] != 0)
	  break;
      _vec_len (a) = i + 1;
    }
  return a;
}

/** Sets the ith bit of a bitmap to new_value.
    No sanity checking. Be careful.
    @param a - pointer to the bitmap
    @param i - the bit position to interrogate
    @param new_value - new value for the bit
    @returns the old value of the bit
*/
always_inline uword
clib_bitmap_set_no_check (uword * a, uword i, uword new_value)
{
  uword i0 = i / BITS (a[0]);
  uword i1 = i % BITS (a[0]);
  uword bit = (uword) 1 << i1;
  uword ai, old_value;

  /* Removed ASSERT since uword * a may not be a vector. */
  /* ASSERT (i0 < vec_len (a)); */

  ai = a[i0];
  old_value = (ai & bit) != 0;
  ai &= ~bit;
  ai |= ((uword) (new_value != 0)) << i1;
  a[i0] = ai;
  return old_value;
}

/** Sets the ith bit of a bitmap to new_value
    Removes trailing zeros from the bitmap
    @param ai - pointer to the bitmap
    @param i - the bit position to interrogate
    @param value - new value for the bit
    @returns the old value of the bit
*/
always_inline uword *
clib_bitmap_set (uword * ai, uword i, uword value)
{
  uword i0 = i / BITS (ai[0]);
  uword i1 = i % BITS (ai[0]);
  uword a;

  /* Check for writing a zero to beyond end of bitmap. */
  if (value == 0 && i0 >= vec_len (ai))
    return ai;			/* Implied trailing zeros. */

  clib_bitmap_vec_validate (ai, i0);

  a = ai[i0];
  a &= ~((uword) 1 << i1);
  a |= ((uword) (value != 0)) << i1;
  ai[i0] = a;

  /* If bits have been cleared, test for zero. */
  if (a == 0)
    ai = _clib_bitmap_remove_trailing_zeros (ai);

  return ai;
}

/** Gets the ith bit value from a bitmap
    @param ai - pointer to the bitmap
    @param i - the bit position to interrogate
    @returns the indicated bit value
*/
always_inline uword
clib_bitmap_get (uword * ai, uword i)
{
  uword i0 = i / BITS (ai[0]);
  uword i1 = i % BITS (ai[0]);
  return i0 < vec_len (ai) && 0 != ((ai[i0] >> i1) & 1);
}

/** Gets the ith bit value from a bitmap
    Does not sanity-check the bit position. Be 
/*
 * 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>
#include <nat/nat44/ed_inlines.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;
  u8 proto;
  u16 r_port, l_port;
  ip4_address_t *l_addr, *r_addr;
  u32 fib_index;
  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;

      l_addr = &s->out2in.addr;
      r_addr = &s->ext_host_addr;
      fib_index = s->out2in.fib_index;
      if (snat_is_unk_proto_session (s))
	{
	  proto = s->in2out.port;
	  r_port = 0;
	  l_port = 0;
	}
      else
	{
	  proto = nat_proto_to_ip_proto (s->in2out.protocol);
	  l_port = s->out2in.port;
	  r_port = s->ext_host_port;
	}
      make_ed_kv (l_addr, r_addr, proto, fib_index, l_port, r_port, ~0ULL,
		  &ed_kv);
      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:
      nat_ed_session_delete (sm, s, ctx->thread_index, 1);
      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)
{
  vlib_main_t *vm = vlib_get_main ();

  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
				     (vm, b0), thread_index);
      /* Per-user LRU list maintenance */
      nat44_session_update_lru (sm, s0, thread_index);
    }
  return next0;
}

static_always_inline u16
snat_random_port (u16 min, u16 max)
{
  snat_main_t *sm = &snat_main;
  return min + random_u32 (&sm->random_seed) /
    (random_u32_max () / (max - min + 1) + 1);
}

static int
nat_ed_alloc_addr_and_port (snat_main_t * sm, u32 rx_fib_index,
			    u32 nat_proto, u32 thread_index,
			    ip4_address_t r_addr, u16 r_port, u8 proto,
			    u16 port_per_thread, u32 snat_thread_index,
			    snat_session_t * s,
			    ip4_address_t * allocated_addr,
			    u16 * allocated_port,
			    clib_bihash_kv_16_8_t * out2in_ed_kv)
{
  int i;
  snat_address_t *a, *ga = 0;
  u32 portnum;
  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];

  const u16 port_thread_offset = (port_per_thread * snat_thread_index) + 1024;

  for (i = 0; i < vec_len (sm->addresses); i++)
    {
      a = sm->addresses + i;
      switch (nat_proto)
	{
#define _(N, j, n, unused)                                                    \
  case NAT_PROTOCOL_##N:                                                     \
    if (a->fib_index == rx_fib_index)                                         \
      {                                                                       \
        u16 port = snat_random_port (1, port_per_thread);                     \
        u16 attempts = port_per_thread;                                       \
        while (attempts > 0)                                                  \
          {                                                                   \
            --attempts;                                                       \
            portnum = port_thread_offset + port;                              \
            make_ed_kv (&a->addr, &r_addr, proto, s->out2in.fib_index,        \
                        clib_host_to_net_u16 (portnum), r_port,               \
                        s - tsm->sessions, out2in_ed_kv);                     \
            int rv = clib_bihash_add_del_16_8 (&tsm->out2in_ed, out2in_ed_kv, \
                                               2 /* is_add */);               \
            if (0 == rv)                                                      \
              {                                                               \
                ++a->busy_##n##_port_refcounts[portnum];                      \
                a->busy_##n##_ports_per_thread[thread_index]++;               \
                a->busy_##n##_ports++;                                        \
                *allocated_addr = a->addr;                                    \
                *allocated_port = clib_host_to_net_u16 (portnum);             \
                return 0;                                                     \
              }                                                               \
            port = (port + 1) % port_per_thread;                              \
          }                                                                   \
      }                                                                       \
    else if (a->fib_index == ~0)                                              \
      {                                                                       \
        ga = a;                                                               \
      }                                                                       \
    break;

	  foreach_nat_protocol;
	default:
	  nat_elog_info ("unknown protocol");
	  return 1;
	}
    }

  if (ga)
    {
      /* fake fib_index to reuse macro */
      rx_fib_index = ~0;
      a = ga;
      switch (nat_proto)
	{
	  foreach_nat_protocol;
	default:
	  nat_elog_info ("unknown protocol");
	  return 1;
	}
    }

#undef _

  /* Totally out of translations to use... */
  snat_ipfix_logging_addresses_exhausted (thread_index, 0);
  return 1;
}

static u32
slow_path_ed (snat_main_t * sm,
	      vlib_buffer_t * b,
	      ip4_address_t l_addr,
	      ip4_address_t r_addr,
	      u16 l_port,
	      u16 r_port,
	      u8 proto,
	      u32 rx_fib_index,
	      snat_session_t ** sessionp,
	      vlib_node_runtime_t * node, u32 next, u32 thread_index, f64 now)
{
  snat_session_t *s = NULL;
  snat_session_key_t key0, key1;
  lb_nat_type_t lb = 0;
  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
  u32 nat_proto = ip_proto_to_nat_proto (proto);
  nat_outside_fib_t *outside_fib;
  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
  clib_bihash_kv_16_8_t out2in_ed_kv;
  ip4_address_t allocated_addr;
  u16 allocated_port;
  u8 identity_nat;
  fib_prefix_t pfx = {
    .fp_proto = FIB_PROTOCOL_IP4,
    .fp_len = 32,
    .fp_addr = {.ip4.as_u32 = r_addr.as_u32,},
  };
  nat44_is_idle_session_ctx_t ctx;

  if (PREDICT_TRUE (nat_proto == NAT_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];
	  return NAT_NEXT_DROP;
	}
    }

  // TODO: based on fib index do a lookup
  if (PREDICT_FALSE
      (nat44_ed_maximum_sessions_exceeded (sm, rx_fib_index, thread_index)))
    {
      if (!nat_lru_free_one (sm, 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 = l_addr;
  key0.port = l_port;
  key1.protocol = key0.protocol = nat_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))
    {
      s = nat_ed_session_alloc (sm, thread_index, now, proto);
      if (!s)
	{
	  nat_elog_warn ("create NAT session failed");
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_USER_SESS_EXCEEDED];
	  return NAT_NEXT_DROP;
	}
      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;
	}

      /* Try to create dynamic translation */
      if (nat_ed_alloc_addr_and_port (sm, rx_fib_index, nat_proto,
				      thread_index, r_addr, r_port, proto,
				      sm->port_per_thread,
				      tsm->snat_thread_index, s,
				      &allocated_addr,
				      &allocated_port, &out2in_ed_kv))
	{
	  nat_elog_notice ("addresses exhausted");
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_OUT_OF_PORTS];
	  nat_ed_session_delete (sm, s, thread_index, 1);
	  return NAT_NEXT_DROP;
	}
      key1.addr = allocated_addr;
      key1.port = allocated_port;
    }
  else
    {
      if (PREDICT_FALSE (identity_nat))
	{
	  *sessionp = s;
	  return next;
	}
      s = nat_ed_session_alloc (sm, thread_index, now, proto);
      if (!s)
	{
	  nat_elog_warn ("create NAT session failed");
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_USER_SESS_EXCEEDED];
	  return NAT_NEXT_DROP;
	}
      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;
	}

      s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;


      make_ed_kv (&key1.addr, &r_addr, proto,
		  s->out2in.fib_index, key1.port, r_port, s - tsm->sessions,
		  &out2in_ed_kv);
      if (clib_bihash_add_or_overwrite_stale_16_8
	  (&tsm->out2in_ed, &out2in_ed_kv, nat44_o2i_ed_is_idle_session_cb,
	   &ctx))
	nat_elog_notice ("out2in-ed key add failed");
    }

  if (lb)
    s->flags |= SNAT_SESSION_FLAG_LOAD_BALANCING;
  s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
  s->ext_host_addr = r_addr;
  s->ext_host_port = r_port;
  s->in2out = key0;
  s->out2in = key1;
  s->out2in.protocol = key0.protocol;

  clib_bihash_kv_16_8_t in2out_ed_kv;
  make_ed_kv (&l_addr, &r_addr, proto, rx_fib_index, l_port, r_port,
	      s - tsm->sessions, &in2out_ed_kv);
  ctx.now = now;
  ctx.thread_index = thread_index;
  if (clib_bihash_add_or_overwrite_stale_16_8 (&tsm->in2out_ed, &in2out_ed_kv,
					       nat44_i2o_ed_is_idle_session_cb,
					       &ctx))
    nat_elog_notice ("in2out-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 (&ip->dst_address, &ip->src_address, ip->protocol,
	      sm->outside_fib_index, udp->dst_port, udp->src_port, ~0ULL,
	      &kv);

  /* 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)
{
  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)
    {
      if (get_icmp_i2o_ed_key (b, ip, 0, ~0ULL, 0, 0, 0, &kv))
	return 0;
    }
  else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
    {
      make_ed_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, ~0ULL, &kv);
    }
  else
    {
      make_ed_kv (&ip->src_address, &ip->dst_address, ip->protocol, 0, 0,
		  0, ~0ULL, &kv);
    }

  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,
				       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 (&ip->src_address, &ip->dst_address, ip->protocol,
	      tx_fib_index, src_port, dst_port, ~0ULL, &kv);
  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);
	  nat_ed_session_delete (sm, s, thread_index, 1);
	}
      else
	s->flags |= SNAT_SESSION_FLAG_OUTPUT_FEATURE;
      return 1;
    }

  /* dst NAT check */
  make_ed_kv (&ip->dst_address, &ip->src_address, ip->protocol,
	      rx_fib_index, dst_port, src_port, ~0ULL, &kv);
  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;
  snat_session_t *s = 0;
  u8 dont_translate = 0;
  clib_bihash_kv_16_8_t kv, value;
  u32 next = ~0;
  int err;
  u16 l_port = 0, r_port = 0;	// initialize to workaround gcc warning
  vlib_main_t *vm = vlib_get_main ();
  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);

  err =
    get_icmp_i2o_ed_key (b, ip, rx_fib_index, ~0ULL, p_proto, &l_port,
			 &r_port, &kv);
  if (err != 0)
    {
      b->error = node->errors[err];
      next = NAT_NEXT_DROP;
      goto out;
    }

  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, l_port, 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, NAT_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, ip->src_address, ip->dst_address, l_port, r_port,
		      ip->protocol, rx_fib_index, &s, node, next,
		      thread_index, vlib_time_now (vm));

      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);
    }
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_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_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 (&ip->src_address, &ip->dst_address, ip->protocol,
	      rx_fib_index, 0, 0, ~0ULL, &s_kv);

  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_ed_maximum_sessions_exceeded
	   (sm, rx_fib_index, 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;
	}

      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;
	}
      else
	{
	  /* *INDENT-OFF* */
	  pool_foreach (s, tsm->sessions, {
      	    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->out2in.addr, &ip->dst_address, ip->protocol,
      	                    outside_fib_index, 0, 0, ~0ULL, &s_kv);
      	        if (clib_bihash_search_16_8 (&tsm->out2in_ed, &s_kv, &s_value))
      	          goto create_ses;

      	        break;
      	      }
      	  });
      	  /* *INDENT-ON* */

	  for (i = 0; i < vec_len (sm->addresses); i++)
	    {
	      make_ed_kv (&sm->addresses[i].addr, &ip->dst_address,
			  ip->protocol, outside_fib_index, 0, 0, ~0ULL,
			  &s_kv);
	      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, thread_index, now, ip->protocol);
      if (!s)
	{
	  b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_USER_SESS_EXCEEDED];
	  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;

      /* Add to lookup tables */
      make_ed_kv (&s->in2out.addr, &ip->dst_address, ip->protocol,
		  rx_fib_index, 0, 0, s - tsm->sessions, &s_kv);
      if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &s_kv, 1))
	nat_elog_notice ("in2out key add failed");

      make_ed_kv (&s->out2in.addr, &ip->dst_address, ip->protocol,
		  outside_fib_index, 0, 0, s - tsm->sessions, &s_kv);
      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;

  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 (&vnet_buffer2 (b0)->nat.arc_next, b0);
	      iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;
	    }

	  next0 = vnet_buffer2 (b0)->nat.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_nat_proto (ip0->protocol);

	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
	    {
	      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 == NAT_PROTOCOL_ICMP))
	    {
	      next0 = def_slow;
	      goto trace0;
	    }

	  make_ed_kv (&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, ~0ULL, &kv0);

	  // 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_closed_timestamp)
	    {
	      if (now >= s0->tcp_closed_timestamp)
		{
		  // session is closed, go slow path
		  next0 = def_slow;
		}
	      else
		{
		  // session in transitory timeout, drop
		  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)
	    {
	      nat_free_session_data (sm, s0, thread_index, 0);
	      nat_ed_session_delete (sm, s0, thread_index, 1);
	      // session is closed, 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 == NAT_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 == vnet_buffer2 (b0)->nat.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 = vnet_buffer2 (b0)->nat.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_nat_proto (ip0->protocol);

	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
	    {
	      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 == NAT_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 (&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, ~0ULL, &kv0);

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

	      if (s0->tcp_closed_timestamp && now >= s0->tcp_closed_timestamp)
		{
		  nat_free_session_data (sm, s0, thread_index, 0);
		  nat_ed_session_delete (sm, s0, thread_index, 1);
		  s0 = NULL;
		}
	    }

	  if (!s0)
	    {
	      if (is_output_feature)
		{
		  if (PREDICT_FALSE
		      (nat44_ed_not_translate_output_feature
		       (sm, ip0, 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 == NAT_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, ip0->src_address, ip0->dst_address,
			      vnet_buffer (b0)->ip.reass.l4_src_port,
			      vnet_buffer (b0)->ip.reass.l4_dst_port,
			      ip0->protocol, rx_fib_index0, &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 == NAT_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 == vnet_buffer2 (b0)->nat.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 arc_next_index %d", t->next_index,
		 t->arc_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:
 */