text: /*
   * 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:
   */
  