text: /*
   * Copyright (c) 2016 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 EI inside to outside network translation
   */
  
  #include <vlib/vlib.h>
  
  #include <vnet/vnet.h>
  #include <vnet/ip/ip.h>
  #include <vnet/ethernet/ethernet.h>
  #include <vnet/udp/udp_local.h>
  #include <vnet/fib/ip4_fib.h>
  
  #include <vppinfra/hash.h>
  #include <vppinfra/error.h>
  
  #include <nat/lib/log.h>
  #include <nat/lib/nat_syslog.h>
  #include <nat/lib/ipfix_logging.h>
  #include <nat/lib/nat_inlines.h>
  #include <nat/nat44-ei/nat44_ei_inlines.h>
  #include <nat/nat44-ei/nat44_ei.h>
  #include <nat/nat44-ei/nat44_ei_hairpinning.h>
  
  typedef struct
  {
    u32 sw_if_index;
    u32 next_index;
    u32 session_index;
    u32 is_slow_path;
    u32 is_hairpinning;
  } nat44_ei_in2out_trace_t;
  
  /* packet trace format function */
  static u8 *
  format_nat44_ei_in2out_trace (u8 *s, va_list *args)
  {
    CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
    CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
    nat44_ei_in2out_trace_t *t = va_arg (*args, nat44_ei_in2out_trace_t *);
    char *tag;
  
    tag = t->is_slow_path ? "NAT44_IN2OUT_SLOW_PATH" : "NAT44_IN2OUT_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);
    if (t->is_hairpinning)
      {
        s = format (s, ", with-hairpinning");
      }
  
    return s;
  }
  
  static u8 *
  format_nat44_ei_in2out_fast_trace (u8 *s, va_list *args)
  {
    CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
    CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
    nat44_ei_in2out_trace_t *t = va_arg (*args, nat44_ei_in2out_trace_t *);
  
    s = format (s, "NAT44_IN2OUT_FAST: sw_if_index %d, next index %d",
  	      t->sw_if_index, t->next_index);
  
    return s;
  }
  
  #define foreach_nat44_ei_in2out_error                                         \
    _ (UNSUPPORTED_PROTOCOL, "unsupported protocol")                            \
    _ (OUT_OF_PORTS, "out of ports")                                            \
    _ (BAD_OUTSIDE_FIB, "outside VRF ID not found")                             \
    _ (BAD_ICMP_TYPE, "unsupported ICMP type")                                  \
    _ (NO_TRANSLATION, "no translation")                                        \
    _ (MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")                      \
    _ (CANNOT_CREATE_USER, "cannot create NAT user")
  
  typedef enum
  {
  #define _(sym, str) NAT44_EI_IN2OUT_ERROR_##sym,
    foreach_nat44_ei_in2out_error
  #undef _
      NAT44_EI_IN2OUT_N_ERROR,
  } nat44_ei_in2out_error_t;
  
  static char *nat44_ei_in2out_error_strings[] = {
  #define _(sym,string) string,
    foreach_nat44_ei_in2out_error
  #undef _
  };
  
  typedef enum
  {
    NAT44_EI_IN2OUT_NEXT_LOOKUP,
    NAT44_EI_IN2OUT_NEXT_DROP,
    NAT44_EI_IN2OUT_NEXT_ICMP_ERROR,
    NAT44_EI_IN2OUT_NEXT_SLOW_PATH,
    NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF,
    NAT44_EI_IN2OUT_N_NEXT,
  } nat44_ei_in2out_next_t;
  
  typedef enum
  {
    NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP,
    NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP,
    NAT44_EI_IN2OUT_HAIRPINNING_FINISH_N_NEXT,
  } nat44_ei_in2out_hairpinnig_finish_next_t;
  
  static inline int
  nat44_ei_not_translate_fast (vlib_node_runtime_t *node, u32 sw_if_index0,
  			     ip4_header_t *ip0, u32 proto0, u32 rx_fib_index0)
  {
    nat44_ei_main_t *nm = &nat44_ei_main;
  
    if (nm->out2in_dpo)
      return 0;
  
    fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
    nat44_ei_outside_fib_t *outside_fib;
    fib_prefix_t pfx = {
      .fp_proto = FIB_PROTOCOL_IP4,
      .fp_len = 32,
      .fp_addr = {
  		.ip4.as_u32 = ip0->dst_address.as_u32,
  		}
      ,
    };
  
    /* Don't NAT packet aimed at the intfc address */
    if (PREDICT_FALSE (nat44_ei_is_interface_addr (
  	nm->ip4_main, node, sw_if_index0, ip0->dst_address.as_u32)))
      return 1;
  
    fei = fib_table_lookup (rx_fib_index0, &pfx);
    if (FIB_NODE_INDEX_INVALID != fei)
      {
        u32 sw_if_index = fib_entry_get_resolving_interface (fei);
        if (sw_if_index == ~0)
  	{
  	  vec_foreach (outside_fib, nm->outside_fibs)
  	    {
  	      fei = fib_table_lookup (outside_fib->fib_index, &pfx);
  	      if (FIB_NODE_INDEX_INVALID != fei)
  		{
  		  sw_if_index = fib_entry_get_resolving_interface (fei);
  		  if (sw_if_index != ~0)
  		    break;
  		}
  	    }
  	}
        if (sw_if_index == ~0)
  	return 1;
  
        nat44_ei_interface_t *i;
        pool_foreach (i, nm->interfaces)
  	{
  	  /* NAT packet aimed at outside interface */
  	  if ((nat44_ei_interface_is_outside (i)) &&
  	      (sw_if_index == i->sw_if_index))
  	    return 0;
  	}
      }
  
    return 1;
  }
  
  static inline int
  nat44_ei_not_translate (nat44_ei_main_t *nm, vlib_node_runtime_t *node,
  			u32 sw_if_index0, ip4_header_t *ip0, u32 proto0,
  			u32 rx_fib_index0, u32 thread_index)
  {
    udp_header_t *udp0 = ip4_next_header (ip0);
    clib_bihash_kv_8_8_t kv0, value0;
  
    init_nat_k (&kv0, ip0->dst_address, udp0->dst_port, nm->outside_fib_index,
  	      proto0);
  
    /* NAT packet aimed at external address if */
    /* has active sessions */
    if (clib_bihash_search_8_8 (&nm->out2in, &kv0, &value0))
      {
        /* or is static mappings */
        ip4_address_t placeholder_addr;
        u16 placeholder_port;
        u32 placeholder_fib_index;
        if (!nat44_ei_static_mapping_match (ip0->dst_address, udp0->dst_port,
  					  nm->outside_fib_index, proto0,
  					  &placeholder_addr, &placeholder_port,
  					  &placeholder_fib_index, 1, 0, 0))
  	return 0;
      }
    else
      return 0;
  
    if (nm->forwarding_enabled)
      return 1;
  
    return nat44_ei_not_translate_fast (node, sw_if_index0, ip0, proto0,
  				      rx_fib_index0);
  }
  
  static inline int
  nat44_ei_not_translate_output_feature (nat44_ei_main_t *nm, ip4_header_t *ip0,
  				       u32 proto0, u16 src_port, u16 dst_port,
  				       u32 thread_index, u32 sw_if_index)
  {
    clib_bihash_kv_8_8_t kv0, value0;
    nat44_ei_interface_t *i;
  
    /* src NAT check */
    init_nat_k (&kv0, ip0->src_address, src_port,
  	      ip4_fib_table_get_index_for_sw_if_index (sw_if_index), proto0);
  
    if (!clib_bihash_search_8_8 (&nm->out2in, &kv0, &value0))
      return 1;
  
    /* dst NAT check */
    init_nat_k (&kv0, ip0->dst_address, dst_port,
  	      ip4_fib_table_get_index_for_sw_if_index (sw_if_index), proto0);
    if (!clib_bihash_search_8_8 (&nm->in2out, &kv0, &value0))
      {
        /* hairpinning */
        pool_foreach (i, nm->output_feature_interfaces)
  	{
  	  if ((nat44_ei_interface_is_inside (i)) &&
  	      (sw_if_index == i->sw_if_index))
  	    return 0;
  	}
        return 1;
      }
  
    return 0;
  }
  
  #ifndef CLIB_MARCH_VARIANT
  int
  nat44_i2o_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
  {
    nat44_ei_main_t *nm = &nat44_ei_main;
    nat44_ei_is_idle_session_ctx_t *ctx = arg;
    nat44_ei_session_t *s;
    u64 sess_timeout_time;
    nat44_ei_main_per_thread_data_t *tnm =
      vec_elt_at_index (nm->per_thread_data, ctx->thread_index);
    clib_bihash_kv_8_8_t s_kv;
  
    s = pool_elt_at_index (tnm->sessions, kv->value);
    sess_timeout_time = s->last_heard + (f64) nat_session_get_timeout (
  					&nm->timeouts, s->nat_proto, s->state);
    if (ctx->now >= sess_timeout_time)
      {
        init_nat_o2i_k (&s_kv, s);
        if (clib_bihash_add_del_8_8 (&nm->out2in, &s_kv, 0))
  	nat_elog_warn (nm, "out2in key del failed");
  
        nat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
  					  s->in2out.addr.as_u32,
  					  s->out2in.addr.as_u32,
  					  s->nat_proto,
  					  s->in2out.port,
  					  s->out2in.port,
  					  s->in2out.fib_index);
  
        nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
  			       &s->in2out.addr, s->in2out.port,
  			       &s->out2in.addr, s->out2in.port, s->nat_proto);
  
        nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
  		   s->ext_host_port, s->nat_proto, s->out2in.fib_index,
  		   ctx->thread_index);
  
        if (!nat44_ei_is_session_static (s))
  	nat44_ei_free_outside_address_and_port (
  	  nm->addresses, ctx->thread_index, &s->out2in.addr, s->out2in.port,
  	  s->nat_proto);
  
        nat44_ei_delete_session (nm, s, ctx->thread_index);
        return 1;
      }
  
    return 0;
  }
  #endif
  
  static u32
  slow_path (nat44_ei_main_t *nm, vlib_buffer_t *b0, ip4_header_t *ip0,
  	   ip4_address_t i2o_addr, u16 i2o_port, u32 rx_fib_index0,
  	   nat_protocol_t nat_proto, nat44_ei_session_t **sessionp,
  	   vlib_node_runtime_t *node, u32 next0, u32 thread_index, f64 now)
  {
    nat44_ei_user_t *u;
    nat44_ei_session_t *s = 0;
    clib_bihash_kv_8_8_t kv0;
    u8 is_sm = 0;
    nat44_ei_outside_fib_t *outside_fib;
    fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
    u8 identity_nat;
    fib_prefix_t pfx = {
      .fp_proto = FIB_PROTOCOL_IP4,
      .fp_len = 32,
      .fp_addr = {
  		.ip4.as_u32 = ip0->dst_address.as_u32,
  		},
    };
    nat44_ei_is_idle_session_ctx_t ctx0;
    ip4_address_t sm_addr;
    u16 sm_port;
    u32 sm_fib_index;
  
    if (PREDICT_FALSE (nat44_ei_maximum_sessions_exceeded (nm, thread_index)))
      {
        b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_MAX_SESSIONS_EXCEEDED];
        nat_ipfix_logging_max_sessions (thread_index,
  				      nm->max_translations_per_thread);
        nat_elog_notice (nm, "maximum sessions exceeded");
        return NAT44_EI_IN2OUT_NEXT_DROP;
      }
  
    /* First try to match static mapping by local address and port */
    if (nat44_ei_static_mapping_match (i2o_addr, i2o_port, rx_fib_index0,
  				     nat_proto, &sm_addr, &sm_port,
  				     &sm_fib_index, 0, 0, &identity_nat))
      {
        /* Try to create dynamic translation */
        if (nm->alloc_addr_and_port (
  	    nm->addresses, rx_fib_index0, thread_index, nat_proto,
  	    ip0->src_address, &sm_addr, &sm_port, nm->port_per_thread,
  	    nm->per_thread_data[thread_index].snat_thread_index))
  	{
  	  b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_OUT_OF_PORTS];
  	  return NAT44_EI_IN2OUT_NEXT_DROP;
  	}
      }
    else
      {
        if (PREDICT_FALSE (identity_nat))
  	{
  	  *sessionp = s;
  	  return next0;
  	}
  
        is_sm = 1;
      }
  
    u = nat44_ei_user_get_or_create (nm, &ip0->src_address, rx_fib_index0,
  				   thread_index);
    if (!u)
      {
        b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_CANNOT_CREATE_USER];
        return NAT44_EI_IN2OUT_NEXT_DROP;
      }
  
    s = nat44_ei_session_alloc_or_recycle (nm, u, thread_index, now);
    if (!s)
      {
        nat44_ei_delete_user_with_no_session (nm, u, thread_index);
        nat_elog_warn (nm, "create NAT session failed");
        return NAT44_EI_IN2OUT_NEXT_DROP;
      }
  
    if (is_sm)
      s->flags |= NAT44_EI_SESSION_FLAG_STATIC_MAPPING;
    nat44_ei_user_session_increment (nm, u, is_sm);
    s->in2out.addr = i2o_addr;
    s->in2out.port = i2o_port;
    s->in2out.fib_index = rx_fib_index0;
    s->nat_proto = nat_proto;
    s->out2in.addr = sm_addr;
    s->out2in.port = sm_port;
    s->out2in.fib_index = nm->outside_fib_index;
    switch (vec_len (nm->outside_fibs))
      {
      case 0:
        s->out2in.fib_index = nm->outside_fib_index;
        break;
      case 1:
        s->out2in.fib_index = nm->outside_fibs[0].fib_index;
        break;
      default:
        vec_foreach (outside_fib, nm->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;
  		}
  	    }
  	}
        break;
      }
    s->ext_host_addr.as_u32 = ip0->dst_address.as_u32;
    s->ext_host_port = vnet_buffer (b0)->ip.reass.l4_dst_port;
    *sessionp = s;
  
    /* Add to translation hashes */
    ctx0.now = now;
    ctx0.thread_index = thread_index;
    init_nat_i2o_kv (&kv0, s, thread_index,
  		   s - nm->per_thread_data[thread_index].sessions);
    if (clib_bihash_add_or_overwrite_stale_8_8 (
  	&nm->in2out, &kv0, nat44_i2o_is_idle_session_cb, &ctx0))
      nat_elog_notice (nm, "in2out key add failed");
  
    init_nat_o2i_kv (&kv0, s, thread_index,
  		   s - nm->per_thread_data[thread_index].sessions);
    if (clib_bihash_add_or_overwrite_stale_8_8 (
  	&nm->out2in, &kv0, nat44_o2i_is_idle_session_cb, &ctx0))
      nat_elog_notice (nm, "out2in key add failed");
  
    /* log NAT event */
    nat_ipfix_logging_nat44_ses_create (
      thread_index, s->in2out.addr.as_u32, s->out2in.addr.as_u32, s->nat_proto,
      s->in2out.port, s->out2in.port, s->in2out.fib_index);
  
    nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index, &s->in2out.addr,
  			   s->in2out.port, &s->out2in.addr, s->out2in.port,
  			   s->nat_proto);
  
    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->nat_proto,
  	       s->in2out.fib_index, s->flags, thread_index, 0);
  
    return next0;
  }
  
  #ifndef CLIB_MARCH_VARIANT
  static_always_inline nat44_ei_in2out_error_t
  icmp_get_key (vlib_buffer_t *b, ip4_header_t *ip0, ip4_address_t *addr,
  	      u16 *port, nat_protocol_t *nat_proto)
  {
    icmp46_header_t *icmp0;
    icmp_echo_header_t *echo0, *inner_echo0 = 0;
    ip4_header_t *inner_ip0 = 0;
    void *l4_header = 0;
    icmp46_header_t *inner_icmp0;
  
    icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
    echo0 = (icmp_echo_header_t *) (icmp0 + 1);
  
    if (!icmp_type_is_error_message
        (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
      {
        *nat_proto = NAT_PROTOCOL_ICMP;
        *addr = ip0->src_address;
        *port = vnet_buffer (b)->ip.reass.l4_src_port;
      }
    else
      {
        inner_ip0 = (ip4_header_t *) (echo0 + 1);
        l4_header = ip4_next_header (inner_ip0);
        *nat_proto = ip_proto_to_nat_proto (inner_ip0->protocol);
        *addr = inner_ip0->dst_address;
        switch (*nat_proto)
  	{
  	case NAT_PROTOCOL_ICMP:
  	  inner_icmp0 = (icmp46_header_t *) l4_header;
  	  inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
  	  *port = inner_echo0->identifier;
  	  break;
  	case NAT_PROTOCOL_UDP:
  	case NAT_PROTOCOL_TCP:
  	  *port = ((tcp_udp_header_t *) l4_header)->dst_port;
  	  break;
  	default:
  	  return NAT44_EI_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL;
  	}
      }
    return -1;			/* success */
  }
  
  /**
   * Get address and port values to be used for ICMP packet translation
   * and create session if needed
   *
   * @param[in,out] nm             NAT main
   * @param[in,out] node           NAT node runtime
   * @param[in] thread_index       thread index
   * @param[in,out] b0             buffer containing packet to be translated
   * @param[in,out] ip0            ip header
   * @param[out] p_proto           protocol used for matching
   * @param[out] p_value           address and port after NAT translation
   * @param[out] p_dont_translate  if packet should not be translated
   * @param d                      optional parameter
   * @param e                      optional parameter
   */
  u32
  nat44_ei_icmp_match_in2out_slow (vlib_node_runtime_t *node, u32 thread_index,
  				 vlib_buffer_t *b0, ip4_header_t *ip0,
  				 ip4_address_t *addr, u16 *port,
  				 u32 *fib_index, nat_protocol_t *proto,
  				 nat44_ei_session_t **p_s0, u8 *dont_translate)
  {
    nat44_ei_main_t *nm = &nat44_ei_main;
    nat44_ei_main_per_thread_data_t *tnm = &nm->per_thread_data[thread_index];
    u32 sw_if_index0;
    nat44_ei_session_t *s0 = 0;
    clib_bihash_kv_8_8_t kv0, value0;
    u32 next0 = ~0;
    int err;
    vlib_main_t *vm = vlib_get_main ();
    *dont_translate = 0;
  
    sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
    *fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
  
    err = icmp_get_key (b0, ip0, addr, port, proto);
    if (err != -1)
      {
        b0->error = node->errors[err];
        next0 = NAT44_EI_IN2OUT_NEXT_DROP;
        goto out;
      }
  
    init_nat_k (&kv0, *addr, *port, *fib_index, *proto);
    if (clib_bihash_search_8_8 (&nm->in2out, &kv0, &value0))
      {
        if (vnet_buffer (b0)->sw_if_index[VLIB_TX] != ~0)
  	{
  	  if (PREDICT_FALSE (nat44_ei_not_translate_output_feature (
  		nm, ip0, *proto, *port, *port, thread_index, sw_if_index0)))
  	    {
  	      *dont_translate = 1;
  	      goto out;
  	    }
  	}
        else
  	{
  	  if (PREDICT_FALSE (nat44_ei_not_translate (
  		nm, node, sw_if_index0, ip0, NAT_PROTOCOL_ICMP, *fib_index,
  		thread_index)))
  	    {
  	      *dont_translate = 1;
  	      goto out;
  	    }
  	}
  
        if (PREDICT_FALSE
  	  (icmp_type_is_error_message
  	   (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags)))
  	{
  	  b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_BAD_ICMP_TYPE];
  	  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
  	  goto out;
  	}
  
        next0 = slow_path (nm, b0, ip0, *addr, *port, *fib_index, *proto, &s0,
  			 node, next0, thread_index, vlib_time_now (vm));
  
        if (PREDICT_FALSE (next0 == NAT44_EI_IN2OUT_NEXT_DROP))
  	goto out;
  
        if (!s0)
  	{
  	  *dont_translate = 1;
  	  goto out;
  	}
      }
    else
      {
        if (PREDICT_FALSE
  	  (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
  	   ICMP4_echo_request
  	   && vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
  	   ICMP4_echo_reply
  	   && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
  					   reass.icmp_type_or_tcp_flags)))
  	{
  	  b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_BAD_ICMP_TYPE];
  	  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
  	  goto out;
  	}
  
        s0 = pool_elt_at_index (tnm->sessions,
  			      nat_value_get_session_index (&value0));
      }
  
  out:
    if (s0)
      {
        *addr = s0->out2in.addr;
        *port = s0->out2in.port;
        *fib_index = s0->out2in.fib_index;
      }
    if (p_s0)
      *p_s0 = s0;
    return next0;
  }
  #endif
  
  #ifndef CLIB_MARCH_VARIANT
  u32
  nat44_ei_icmp_match_in2out_fast (vlib_node_runtime_t *node, u32 thread_index,
  				 vlib_buffer_t *b0, ip4_header_t *ip0,
  				 ip4_address_t *addr, u16 *port,
  				 u32 *fib_index, nat_protocol_t *proto,
  				 nat44_ei_session_t **s0, u8 *dont_translate)
  {
    u32 sw_if_index0;
    u8 is_addr_only;
    u32 next0 = ~0;
    int err;
    *dont_translate = 0;
  
    sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
    *fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
  
    err = icmp_get_key (b0, ip0, addr, port, proto);
    if (err != -1)
      {
        b0->error = node->errors[err];
        next0 = NAT44_EI_IN2OUT_NEXT_DROP;
        goto out;
      }
  
    ip4_address_t sm_addr;
    u16 sm_port;
    u32 sm_fib_index;
  
    if (nat44_ei_static_mapping_match (*addr, *port, *fib_index, *proto,
  				     &sm_addr, &sm_port, &sm_fib_index, 0,
  				     &is_addr_only, 0))
      {
        if (PREDICT_FALSE (nat44_ei_not_translate_fast (
  	    node, sw_if_index0, ip0, IP_PROTOCOL_ICMP, *fib_index)))
  	{
  	  *dont_translate = 1;
  	  goto out;
  	}
  
        if (icmp_type_is_error_message
  	  (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags))
  	{
  	  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
  	  goto out;
  	}
  
        b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_NO_TRANSLATION];
        next0 = NAT44_EI_IN2OUT_NEXT_DROP;
        goto out;
      }
  
    if (PREDICT_FALSE
        (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_request
         && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
  	   ICMP4_echo_reply || !is_addr_only)
         && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
  				       reass.icmp_type_or_tcp_flags)))
      {
        b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_BAD_ICMP_TYPE];
        next0 = NAT44_EI_IN2OUT_NEXT_DROP;
        goto out;
      }
  
  out:
    return next0;
  }
  #endif
  
  u32 nat44_ei_icmp_in2out (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, u32 thread_index,
  			  nat44_ei_session_t **p_s0);
  
  #ifndef CLIB_MARCH_VARIANT
  u32
  nat44_ei_icmp_in2out (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,
  		      u32 thread_index, nat44_ei_session_t **p_s0)
  {
    nat44_ei_main_t *nm = &nat44_ei_main;
    vlib_main_t *vm = vlib_get_main ();
    ip4_address_t addr;
    u16 port;
    u32 fib_index;
    nat_protocol_t proto;
    icmp_echo_header_t *echo0, *inner_echo0 = 0;
    ip4_header_t *inner_ip0;
    void *l4_header = 0;
    icmp46_header_t *inner_icmp0;
    u8 dont_translate;
    u32 new_addr0, old_addr0;
    u16 old_id0, new_id0;
    u16 old_checksum0, new_checksum0;
    ip_csum_t sum0;
    u16 checksum0;
    u32 next0_tmp;
    u32 required_thread_index = thread_index;
  
    echo0 = (icmp_echo_header_t *) (icmp0 + 1);
  
    if (PREDICT_TRUE (nm->pat))
      {
        next0_tmp = nat44_ei_icmp_match_in2out_slow (
  	node, thread_index, b0, ip0, &addr, &port, &fib_index, &proto, p_s0,
  	&dont_translate);
      }
    else
      {
        next0_tmp = nat44_ei_icmp_match_in2out_fast (
  	node, thread_index, b0, ip0, &addr, &port, &fib_index, &proto, p_s0,
  	&dont_translate);
      }
  
    if (next0_tmp != ~0)
      next0 = next0_tmp;
    if (next0 == NAT44_EI_IN2OUT_NEXT_DROP || dont_translate)
      goto out;
  
    if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
      {
        sum0 =
  	ip_incremental_checksum_buffer (vm, b0,
  					(u8 *) icmp0 -
  					(u8 *) vlib_buffer_get_current (b0),
  					ntohs (ip0->length) -
  					ip4_header_bytes (ip0), 0);
        checksum0 = ~ip_csum_fold (sum0);
        if (PREDICT_FALSE (checksum0 != 0 && checksum0 != 0xffff))
  	{
  	  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
  	  goto out;
  	}
      }
  
    old_addr0 = ip0->src_address.as_u32;
    new_addr0 = ip0->src_address.as_u32 = addr.as_u32;
  
    sum0 = ip0->checksum;
    sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
  			 src_address /* changed member */ );
    ip0->checksum = ip_csum_fold (sum0);
  
    if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
      {
        if (icmp0->checksum == 0)
  	icmp0->checksum = 0xffff;
  
        if (!icmp_type_is_error_message (icmp0->type))
  	{
  	  new_id0 = port;
  	  if (PREDICT_FALSE (new_id0 != echo0->identifier))
  	    {
  	      old_id0 = echo0->identifier;
  	      new_id0 = port;
  	      echo0->identifier = new_id0;
  
  	      sum0 = icmp0->checksum;
  	      sum0 =
  		ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
  				identifier);
  	      icmp0->checksum = ip_csum_fold (sum0);
  	    }
  	}
        else
  	{
  	  inner_ip0 = (ip4_header_t *) (echo0 + 1);
  	  l4_header = ip4_next_header (inner_ip0);
  
  	  if (!ip4_header_checksum_is_valid (inner_ip0))
  	    {
  	      next0 = NAT44_EI_IN2OUT_NEXT_DROP;
  	      goto out;
  	    }
  
  	  /* update inner destination IP address */
  	  old_addr0 = inner_ip0->dst_address.as_u32;
  	  inner_ip0->dst_address = addr;
  	  new_addr0 = inner_ip0->dst_address.as_u32;
  	  sum0 = icmp0->checksum;
  	  sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
  				 dst_address /* changed member */ );
  	  icmp0->checksum = ip_csum_fold (sum0);
  
  	  /* update inner IP header checksum */
  	  old_checksum0 = inner_ip0->checksum;
  	  sum0 = inner_ip0->checksum;
  	  sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
  				 dst_address /* changed member */ );
  	  inner_ip0->checksum = ip_csum_fold (sum0);
  	  new_checksum0 = inner_ip0->checksum;
  	  sum0 = icmp0->checksum;
  	  sum0 =
  	    ip_csum_update (sum0, old_checksum0, new_checksum0, ip4_header_t,
  			    checksum);
  	  icmp0->checksum = ip_csum_fold (sum0);
  
  	  switch (proto)
  	    {
  	    case NAT_PROTOCOL_ICMP:
  	      inner_icmp0 = (icmp46_header_t *) l4_header;
  	      inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
  
  	      old_id0 = inner_echo0->identifier;
  	      new_id0 = port;
  	      inner_echo0->identifier = new_id0;
  
  	      sum0 = icmp0->checksum;
  	      sum0 =
  		ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
  				identifier);
  	      icmp0->checksum = ip_csum_fold (sum0);
  	      break;
  	    case NAT_PROTOCOL_UDP:
  	    case NAT_PROTOCOL_TCP:
  	      old_id0 = ((tcp_udp_header_t *) l4_header)->dst_port;
  	      new_id0 = port;
  	      ((tcp_udp_header_t *) l4_header)->dst_port = new_id0;
  
  	      sum0 = icmp0->checksum;
  	      sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
  				     dst_port);
  	      icmp0->checksum = ip_csum_fold (sum0);
  	      break;
  	    default:
  	      ASSERT (0);
  	    }
  	}
      }
  
    if (vnet_buffer (b0)->sw_if_index[VLIB_TX] == ~0)
      {
        if (0 != nat44_ei_icmp_hairpinning (nm, b0, thread_index, ip0, icmp0,
  					  &required_thread_index))
  	vnet_buffer (b0)->sw_if_index[VLIB_TX] = fib_index;
        if (thread_index != required_thread_index)
  	{
  	  vnet_buffer (b0)->snat.required_thread_index = required_thread_index;
  	  next0 = NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF;
  	}
      }
  
  out:
    return next0;
  }
  #endif
  
  static_always_inline u32
  nat44_ei_icmp_in2out_slow_path (nat44_ei_main_t *nm, 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, nat44_ei_session_t **p_s0)
  {
    vlib_main_t *vm = vlib_get_main ();
  
    next0 = nat44_ei_icmp_in2out (b0, ip0, icmp0, sw_if_index0, rx_fib_index0,
  				node, next0, thread_index, p_s0);
    nat44_ei_session_t *s0 = *p_s0;
    if (PREDICT_TRUE (next0 != NAT44_EI_IN2OUT_NEXT_DROP && s0))
      {
        /* Accounting */
        nat44_ei_session_update_counters (
  	s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
        /* Per-user LRU list maintenance */
        nat44_ei_session_update_lru (nm, s0, thread_index);
      }
    return next0;
  }
  
  static int
  nat_in2out_sm_unknown_proto (nat44_ei_main_t *nm, vlib_buffer_t *b,
  			     ip4_header_t *ip, u32 rx_fib_index)
  {
    clib_bihash_kv_8_8_t kv, value;
    nat44_ei_static_mapping_t *m;
    u32 old_addr, new_addr;
    ip_csum_t sum;
  
    init_nat_k (&kv, ip->src_address, 0, rx_fib_index, 0);
    if (clib_bihash_search_8_8 (&nm->static_mapping_by_local, &kv, &value))
      return 1;
  
    m = pool_elt_at_index (nm->static_mappings, value.value);
  
    old_addr = ip->src_address.as_u32;
    new_addr = ip->src_address.as_u32 = m->external_addr.as_u32;
    sum = ip->checksum;
    sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, src_address);
    ip->checksum = ip_csum_fold (sum);
  
  
    /* Hairpinning */
    if (vnet_buffer (b)->sw_if_index[VLIB_TX] == ~0)
      {
        vnet_buffer (b)->sw_if_index[VLIB_TX] = m->fib_index;
        nat44_ei_hairpinning_sm_unknown_proto (nm, b, ip);
      }
  
    return 0;
  }
  
  static inline uword
  nat44_ei_in2out_node_fn_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
  				vlib_frame_t *frame, int is_slow_path,
  				int is_output_feature)
  {
    u32 n_left_from, *from;
    nat44_ei_main_t *nm = &nat44_ei_main;
    f64 now = vlib_time_now (vm);
    u32 thread_index = vm->thread_index;
  
    from = vlib_frame_vector_args (frame);
    n_left_from = frame->n_vectors;
  
    vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
    u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
    vlib_get_buffers (vm, from, b, n_left_from);
  
    while (n_left_from >= 2)
      {
        vlib_buffer_t *b0, *b1;
        u32 next0, next1;
        u32 sw_if_index0, sw_if_index1;
        ip4_header_t *ip0, *ip1;
        ip_csum_t sum0, sum1;
        u32 new_addr0, old_addr0, new_addr1, old_addr1;
        u16 old_port0, new_port0, old_port1, new_port1;
        udp_header_t *udp0, *udp1;
        tcp_header_t *tcp0, *tcp1;
        icmp46_header_t *icmp0, *icmp1;
        u32 rx_fib_index0, rx_fib_index1;
        u32 proto0, proto1;
        nat44_ei_session_t *s0 = 0, *s1 = 0;
        clib_bihash_kv_8_8_t kv0, value0, kv1, value1;
        u32 iph_offset0 = 0, iph_offset1 = 0;
  
        b0 = *b;
        b++;
        b1 = *b;
        b++;
  
        /* Prefetch next iteration. */
        if (PREDICT_TRUE (n_left_from >= 4))
  	{
  	  vlib_buffer_t *p2, *p3;
  
  	  p2 = *b;
  	  p3 = *(b + 1);
  
  	  vlib_prefetch_buffer_header (p2, LOAD);
  	  vlib_prefetch_buffer_header (p3, LOAD);
  
  	  CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
  	  CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
  	}
  
        if (is_output_feature)
  	iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;
  
        ip0 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
  			      iph_offset0);
  
        udp0 = ip4_next_header (ip0);
        tcp0 = (tcp_header_t *) udp0;
        icmp0 = (icmp46_header_t *) udp0;
  
        sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
        rx_fib_index0 =
  	vec_elt (nm->ip4_main->fib_index_by_sw_if_index, sw_if_index0);
  
        next0 = next1 = NAT44_EI_IN2OUT_NEXT_LOOKUP;
  
        if (PREDICT_FALSE (ip0->ttl == 1))
  	{
  	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
  	  icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
  				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
  				       0);
  	  next0 = NAT44_EI_IN2OUT_NEXT_ICMP_ERROR;
  	  goto trace00;
  	}
  
        proto0 = ip_proto_to_nat_proto (ip0->protocol);
  
        /* Next configured feature, probably ip4-lookup */
        if (is_slow_path)
  	{
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
  	    {
  	      if (nat_in2out_sm_unknown_proto (nm, b0, ip0, rx_fib_index0))
  		{
  		  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
  		  b0->error =
  		    node->errors[NAT44_EI_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
  		}
  	      vlib_increment_simple_counter (
  		is_slow_path ? &nm->counters.slowpath.in2out.other :
  			       &nm->counters.fastpath.in2out.other,
  		thread_index, sw_if_index0, 1);
  	      goto trace00;
  	    }
  
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
  	    {
  	      next0 = nat44_ei_icmp_in2out_slow_path (
  		nm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node, next0,
  		now, thread_index, &s0);
  	      vlib_increment_simple_counter (
  		is_slow_path ? &nm->counters.slowpath.in2out.icmp :
  			       &nm->counters.fastpath.in2out.icmp,
  		thread_index, sw_if_index0, 1);
  	      goto trace00;
  	    }
  	}
        else
  	{
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
  	    {
  	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
  	      goto trace00;
  	    }
  
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
  	    {
  	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
  	      goto trace00;
  	    }
  	}
  
        init_nat_k (&kv0, ip0->src_address,
  		  vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
  		  proto0);
        if (PREDICT_FALSE (clib_bihash_search_8_8 (&nm->in2out, &kv0, &value0) !=
  			 0))
  	{
  	  if (is_slow_path)
  	    {
  	      if (is_output_feature)
  		{
  		  if (PREDICT_FALSE (nat44_ei_not_translate_output_feature (
  			nm, ip0, proto0,
  			vnet_buffer (b0)->ip.reass.l4_src_port,
  			vnet_buffer (b0)->ip.reass.l4_dst_port, thread_index,
  			sw_if_index0)))
  		    goto trace00;
  
  		  /*
  		   * 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 trace00;
  		}
  	      else
  		{
  		  if (PREDICT_FALSE (nat44_ei_not_translate (
  			nm, node, sw_if_index0, ip0, proto0, rx_fib_index0,
  			thread_index)))
  		    goto trace00;
  		}
  
  	      next0 = slow_path (nm, b0, ip0, ip0->src_address,
  				 vnet_buffer (b0)->ip.reass.l4_src_port,
  				 rx_fib_index0, proto0, &s0, node, next0,
  				 thread_index, now);
  	      if (PREDICT_FALSE (next0 == NAT44_EI_IN2OUT_NEXT_DROP))
  		goto trace00;
  
  	      if (PREDICT_FALSE (!s0))
  		goto trace00;
  	    }
  	  else
  	    {
  	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
  	      goto trace00;
  	    }
  	}
        else
  	s0 = pool_elt_at_index (nm->per_thread_data[thread_index].sessions,
  				nat_value_get_session_index (&value0));
  
        b0->flags |= VNET_BUFFER_F_IS_NATED;
  
        old_addr0 = ip0->src_address.as_u32;
        ip0->src_address = s0->out2in.addr;
        new_addr0 = ip0->src_address.as_u32;
        if (!is_output_feature)
  	vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
  
        sum0 = ip0->checksum;
        sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
  			     ip4_header_t, src_address /* changed member */ );
        ip0->checksum = ip_csum_fold (sum0);
  
  
        if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
  	{
  	  if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
  	    {
  	      old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;
  	      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 /* changed member */ );
  	      sum0 = ip_csum_update (sum0, old_port0, new_port0,
  				     ip4_header_t /* cheat */ ,
  				     length /* changed member */ );
  	      mss_clamping (nm->mss_clamping, tcp0, &sum0);
  	      tcp0->checksum = ip_csum_fold (sum0);
  	    }
  	  vlib_increment_simple_counter (is_slow_path ?
  					   &nm->counters.slowpath.in2out.tcp :
  					   &nm->counters.fastpath.in2out.tcp,
  					 thread_index, sw_if_index0, 1);
  	}
        else
  	{
  	  if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
  	    {
  	      udp0->src_port = s0->out2in.port;
  	      if (PREDICT_FALSE (udp0->checksum))
  		{
  		  old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;
  		  new_port0 = udp0->src_port;
  		  sum0 = udp0->checksum;
  		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address	/* changed member */
  		    );
  		  sum0 =
  		    ip_csum_update (sum0, old_port0, new_port0,
  				    ip4_header_t /* cheat */ ,
  				    length /* changed member */ );
  		  udp0->checksum = ip_csum_fold (sum0);
  		}
  	    }
  	  vlib_increment_simple_counter (is_slow_path ?
  					   &nm->counters.slowpath.in2out.udp :
  					   &nm->counters.fastpath.in2out.udp,
  					 thread_index, sw_if_index0, 1);
  	}
  
        /* Accounting */
        nat44_ei_session_update_counters (
  	s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
        /* Per-user LRU list maintenance */
        nat44_ei_session_update_lru (nm, s0, thread_index);
      trace00:
  
        if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
  			 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
  	{
  	  nat44_ei_in2out_trace_t *t =
  	    vlib_add_trace (vm, node, b0, sizeof (*t));
  	  t->is_slow_path = is_slow_path;
  	  t->sw_if_index = sw_if_index0;
  	  t->next_index = next0;
  	  t->session_index = ~0;
  	  if (s0)
  	    t->session_index = s0 - nm->per_thread_data[thread_index].sessions;
  	}
  
        if (next0 == NAT44_EI_IN2OUT_NEXT_DROP)
  	{
  	  vlib_increment_simple_counter (
  	    is_slow_path ? &nm->counters.slowpath.in2out.drops :
  			   &nm->counters.fastpath.in2out.drops,
  	    thread_index, sw_if_index0, 1);
  	}
  
        if (is_output_feature)
  	iph_offset1 = vnet_buffer (b1)->ip.reass.save_rewrite_length;
  
        ip1 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b1) +
  			      iph_offset1);
  
        udp1 = ip4_next_header (ip1);
        tcp1 = (tcp_header_t *) udp1;
        icmp1 = (icmp46_header_t *) udp1;
  
        sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
        rx_fib_index1 =
  	vec_elt (nm->ip4_main->fib_index_by_sw_if_index, sw_if_index1);
  
        if (PREDICT_FALSE (ip1->ttl == 1))
  	{
  	  vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
  	  icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
  				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
  				       0);
  	  next1 = NAT44_EI_IN2OUT_NEXT_ICMP_ERROR;
  	  goto trace01;
  	}
  
        proto1 = ip_proto_to_nat_proto (ip1->protocol);
  
        /* Next configured feature, probably ip4-lookup */
        if (is_slow_path)
  	{
  	  if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
  	    {
  	      if (nat_in2out_sm_unknown_proto (nm, b1, ip1, rx_fib_index1))
  		{
  		  next1 = NAT44_EI_IN2OUT_NEXT_DROP;
  		  b1->error =
  		    node->errors[NAT44_EI_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
  		}
  	      vlib_increment_simple_counter (
  		is_slow_path ? &nm->counters.slowpath.in2out.other :
  			       &nm->counters.fastpath.in2out.other,
  		thread_index, sw_if_index1, 1);
  	      goto trace01;
  	    }
  
  	  if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
  	    {
  	      next1 = nat44_ei_icmp_in2out_slow_path (
  		nm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node, next1,
  		now, thread_index, &s1);
  	      vlib_increment_simple_counter (
  		is_slow_path ? &nm->counters.slowpath.in2out.icmp :
  			       &nm->counters.fastpath.in2out.icmp,
  		thread_index, sw_if_index1, 1);
  	      goto trace01;
  	    }
  	}
        else
  	{
  	  if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
  	    {
  	      next1 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
  	      goto trace01;
  	    }
  
  	  if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
  	    {
  	      next1 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
  	      goto trace01;
  	    }
  	}
  
        init_nat_k (&kv1, ip1->src_address,
  		  vnet_buffer (b1)->ip.reass.l4_src_port, rx_fib_index1,
  		  proto1);
        if (PREDICT_FALSE (clib_bihash_search_8_8 (&nm->in2out, &kv1, &value1) !=
  			 0))
  	{
  	  if (is_slow_path)
  	    {
  	      if (is_output_feature)
  		{
  		  if (PREDICT_FALSE (nat44_ei_not_translate_output_feature (
  			nm, ip1, proto1,
  			vnet_buffer (b1)->ip.reass.l4_src_port,
  			vnet_buffer (b1)->ip.reass.l4_dst_port, thread_index,
  			sw_if_index1)))
  		    goto trace01;
  
  		  /*
  		   * Send DHCP packets to the ipv4 stack, or we won't
  		   * be able to use dhcp client on the outside interface
  		   */
  		  if (PREDICT_FALSE
  		      (proto1 == NAT_PROTOCOL_UDP
  		       && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
  			   clib_host_to_net_u16
  			   (UDP_DST_PORT_dhcp_to_server))
  		       && ip1->dst_address.as_u32 == 0xffffffff))
  		    goto trace01;
  		}
  	      else
  		{
  		  if (PREDICT_FALSE (nat44_ei_not_translate (
  			nm, node, sw_if_index1, ip1, proto1, rx_fib_index1,
  			thread_index)))
  		    goto trace01;
  		}
  
  	      next1 = slow_path (nm, b1, ip1, ip1->src_address,
  				 vnet_buffer (b1)->ip.reass.l4_src_port,
  				 rx_fib_index1, proto1, &s1, node, next1,
  				 thread_index, now);
  	      if (PREDICT_FALSE (next1 == NAT44_EI_IN2OUT_NEXT_DROP))
  		goto trace01;
  
  	      if (PREDICT_FALSE (!s1))
  		goto trace01;
  	    }
  	  else
  	    {
  	      next1 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
  	      goto trace01;
  	    }
  	}
        else
  	s1 = pool_elt_at_index (nm->per_thread_data[thread_index].sessions,
  				nat_value_get_session_index (&value1));
  
        b1->flags |= VNET_BUFFER_F_IS_NATED;
  
        old_addr1 = ip1->src_address.as_u32;
        ip1->src_address = s1->out2in.addr;
        new_addr1 = ip1->src_address.as_u32;
        if (!is_output_feature)
  	vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->out2in.fib_index;
  
        sum1 = ip1->checksum;
        sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
  			     ip4_header_t, src_address /* changed member */ );
        ip1->checksum = ip_csum_fold (sum1);
  
        if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
  	{
  	  if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
  	    {
  	      old_port1 = vnet_buffer (b1)->ip.reass.l4_src_port;
  	      new_port1 = udp1->src_port = s1->out2in.port;
  	      sum1 = tcp1->checksum;
  	      sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
  				     ip4_header_t,
  				     dst_address /* changed member */ );
  	      sum1 = ip_csum_update (sum1, old_port1, new_port1,
  				     ip4_header_t /* cheat */ ,
  				     length /* changed member */ );
  	      mss_clamping (nm->mss_clamping, tcp1, &sum1);
  	      tcp1->checksum = ip_csum_fold (sum1);
  	    }
  	  vlib_increment_simple_counter (is_slow_path ?
  					   &nm->counters.slowpath.in2out.tcp :
  					   &nm->counters.fastpath.in2out.tcp,
  					 thread_index, sw_if_index1, 1);
  	}
        else
  	{
  	  if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
  	    {
  	      udp1->src_port = s1->out2in.port;
  	      if (PREDICT_FALSE (udp1->checksum))
  		{
  		  old_port1 = vnet_buffer (b1)->ip.reass.l4_src_port;
  		  new_port1 = udp1->src_port;
  		  sum1 = udp1->checksum;
  		  sum1 = ip_csum_update (sum1, old_addr1, new_addr1, ip4_header_t, dst_address	/* changed member */
  		    );
  		  sum1 =
  		    ip_csum_update (sum1, old_port1, new_port1,
  				    ip4_header_t /* cheat */ ,
  				    length /* changed member */ );
  		  udp1->checksum = ip_csum_fold (sum1);
  		}
  	    }
  	  vlib_increment_simple_counter (is_slow_path ?
  					   &nm->counters.slowpath.in2out.udp :
  					   &nm->counters.fastpath.in2out.udp,
  					 thread_index, sw_if_index1, 1);
  	}
  
        /* Accounting */
        nat44_ei_session_update_counters (
  	s1, now, vlib_buffer_length_in_chain (vm, b1), thread_index);
        /* Per-user LRU list maintenance */
        nat44_ei_session_update_lru (nm, s1, thread_index);
      trace01:
  
        if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
  			 && (b1->flags & VLIB_BUFFER_IS_TRACED)))
  	{
  	  nat44_ei_in2out_trace_t *t =
  	    vlib_add_trace (vm, node, b1, sizeof (*t));
  	  t->sw_if_index = sw_if_index1;
  	  t->next_index = next1;
  	  t->session_index = ~0;
  	  if (s1)
  	    t->session_index = s1 - nm->per_thread_data[thread_index].sessions;
  	}
  
        if (next1 == NAT44_EI_IN2OUT_NEXT_DROP)
  	{
  	  vlib_increment_simple_counter (
  	    is_slow_path ? &nm->counters.slowpath.in2out.drops :
  			   &nm->counters.fastpath.in2out.drops,
  	    thread_index, sw_if_index1, 1);
  	}
  
        n_left_from -= 2;
        next[0] = next0;
        next[1] = next1;
        next += 2;
      }
  
    while (n_left_from > 0)
      {
        vlib_buffer_t *b0;
        u32 next0;
        u32 sw_if_index0;
        ip4_header_t *ip0;
        ip_csum_t sum0;
        u32 new_addr0, old_addr0;
        u16 old_port0, new_port0;
        udp_header_t *udp0;
        tcp_header_t *tcp0;
        icmp46_header_t *icmp0;
        u32 rx_fib_index0;
        u32 proto0;
        nat44_ei_session_t *s0 = 0;
        clib_bihash_kv_8_8_t kv0, value0;
        u32 iph_offset0 = 0;
  
        b0 = *b;
        b++;
        next0 = NAT44_EI_IN2OUT_NEXT_LOOKUP;
  
        if (is_output_feature)
  	iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;
  
        ip0 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
  			      iph_offset0);
  
        udp0 = ip4_next_header (ip0);
        tcp0 = (tcp_header_t *) udp0;
        icmp0 = (icmp46_header_t *) udp0;
  
        sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
        rx_fib_index0 =
  	vec_elt (nm->ip4_main->fib_index_by_sw_if_index, sw_if_index0);
  
        if (PREDICT_FALSE (ip0->ttl == 1))
  	{
  	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
  	  icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
  				       ICMP4_time_exceeded_ttl_exceeded_in_transit,
  				       0);
  	  next0 = NAT44_EI_IN2OUT_NEXT_ICMP_ERROR;
  	  goto trace0;
  	}
  
        proto0 = ip_proto_to_nat_proto (ip0->protocol);
  
        /* Next configured feature, probably ip4-lookup */
        if (is_slow_path)
  	{
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
  	    {
  	      if (nat_in2out_sm_unknown_proto (nm, b0, ip0, rx_fib_index0))
  		{
  		  next0 = NAT44_EI_IN2OUT_NEXT_DROP;
  		  b0->error =
  		    node->errors[NAT44_EI_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
  		}
  	      vlib_increment_simple_counter (
  		is_slow_path ? &nm->counters.slowpath.in2out.other :
  			       &nm->counters.fastpath.in2out.other,
  		thread_index, sw_if_index0, 1);
  	      goto trace0;
  	    }
  
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
  	    {
  	      next0 = nat44_ei_icmp_in2out_slow_path (
  		nm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node, next0,
  		now, thread_index, &s0);
  	      vlib_increment_simple_counter (
  		is_slow_path ? &nm->counters.slowpath.in2out.icmp :
  			       &nm->counters.fastpath.in2out.icmp,
  		thread_index, sw_if_index0, 1);
  	      goto trace0;
  	    }
  	}
        else
  	{
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
  	    {
  	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
  	      goto trace0;
  	    }
  
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
  	    {
  	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
  	      goto trace0;
  	    }
  	}
  
        init_nat_k (&kv0, ip0->src_address,
  		  vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
  		  proto0);
  
        if (clib_bihash_search_8_8 (&nm->in2out, &kv0, &value0))
  	{
  	  if (is_slow_path)
  	    {
  	      if (is_output_feature)
  		{
  		  if (PREDICT_FALSE (nat44_ei_not_translate_output_feature (
  			nm, ip0, proto0,
  			vnet_buffer (b0)->ip.reass.l4_src_port,
  			vnet_buffer (b0)->ip.reass.l4_dst_port, thread_index,
  			sw_if_index0)))
  		    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_ei_not_translate (
  			nm, node, sw_if_index0, ip0, proto0, rx_fib_index0,
  			thread_index)))
  		    goto trace0;
  		}
  
  	      next0 = slow_path (nm, b0, ip0, ip0->src_address,
  				 vnet_buffer (b0)->ip.reass.l4_src_port,
  				 rx_fib_index0, proto0, &s0, node, next0,
  				 thread_index, now);
  
  	      if (PREDICT_FALSE (next0 == NAT44_EI_IN2OUT_NEXT_DROP))
  		goto trace0;
  
  	      if (PREDICT_FALSE (!s0))
  		goto trace0;
  	    }
  	  else
  	    {
  	      next0 = NAT44_EI_IN2OUT_NEXT_SLOW_PATH;
  	      goto trace0;
  	    }
  	}
        else
  	s0 = pool_elt_at_index (nm->per_thread_data[thread_index].sessions,
  				nat_value_get_session_index (&value0));
  
        b0->flags |= VNET_BUFFER_F_IS_NATED;
  
        old_addr0 = ip0->src_address.as_u32;
        ip0->src_address = s0->out2in.addr;
        new_addr0 = ip0->src_address.as_u32;
        if (!is_output_feature)
  	vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
  
        sum0 = ip0->checksum;
        sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
  			     ip4_header_t, src_address /* changed member */ );
        ip0->checksum = ip_csum_fold (sum0);
  
        if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
  	{
  	  if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
  	    {
  	      old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;
  	      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 /* changed member */ );
  	      sum0 =
  		ip_csum_update (sum0, old_port0, new_port0,
  				ip4_header_t /* cheat */ ,
  				length /* changed member */ );
  	      mss_clamping (nm->mss_clamping, tcp0, &sum0);
  	      tcp0->checksum = ip_csum_fold (sum0);
  	    }
  	  vlib_increment_simple_counter (is_slow_path ?
  					   &nm->counters.slowpath.in2out.tcp :
  					   &nm->counters.fastpath.in2out.tcp,
  					 thread_index, sw_if_index0, 1);
  	}
        else
  	{
  	  if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
  	    {
  	      udp0->src_port = s0->out2in.port;
  	      if (PREDICT_FALSE (udp0->checksum))
  		{
  		  old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;
  		  new_port0 = udp0->src_port;
  		  sum0 = udp0->checksum;
  		  sum0 =
  		    ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
  				    dst_address /* changed member */ );
  		  sum0 =
  		    ip_csum_update (sum0, old_port0, new_port0,
  				    ip4_header_t /* cheat */ ,
  				    length /* changed member */ );
  		  udp0->checksum = ip_csum_fold (sum0);
  		}
  	    }
  	  vlib_increment_simple_counter (is_slow_path ?
  					   &nm->counters.slowpath.in2out.udp :
  					   &nm->counters.fastpath.in2out.udp,
  					 thread_index, sw_if_index0, 1);
  	}
  
        /* Accounting */
        nat44_ei_session_update_counters (
  	s0, now, vlib_buffer_length_in_chain (vm, b0), thread_index);
        /* Per-user LRU list maintenance */
        nat44_ei_session_update_lru (nm, s0, thread_index);
  
      trace0:
        if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
  			 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
  	{
  	  nat44_ei_in2out_trace_t *t =
  	    vlib_add_trace (vm, node, b0, sizeof (*t));
  	  t->is_slow_path = is_slow_path;
  	  t->sw_if_index = sw_if_index0;
  	  t->next_index = next0;
  	  t->session_index = ~0;
  	  if (s0)
  	    t->session_index = s0 - nm->per_thread_data[thread_index].sessions;
  	}
  
        if (next0 == NAT44_EI_IN2OUT_NEXT_DROP)
  	{
  	  vlib_increment_simple_counter (
  	    is_slow_path ? &nm->counters.slowpath.in2out.drops :
  			   &nm->counters.fastpath.in2out.drops,
  	    thread_index, sw_if_index0, 1);
  	}
  
        n_left_from--;
        next[0] = next0;
        next++;
      }
  
    vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
  			       frame->n_vectors);
    return frame->n_vectors;
  }
  
  VLIB_NODE_FN (nat44_ei_in2out_node)
  (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
  {
    return nat44_ei_in2out_node_fn_inline (vm, node, frame, 0 /* is_slow_path */,
  					 0);
  }
  
  VLIB_REGISTER_NODE (nat44_ei_in2out_node) = {
    .name = "nat44-ei-in2out",
    .vector_size = sizeof (u32),
    .format_trace = format_nat44_ei_in2out_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
  
    .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
    .error_strings = nat44_ei_in2out_error_strings,
  
    .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
  
    .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
  
    /* edit / add dispositions here */
    .next_nodes = {
      [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
      [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
      [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-slowpath",
      [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
      [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-ip4-lookup",
    },
  };
  
  VLIB_NODE_FN (nat44_ei_in2out_output_node)
  (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
  {
    return nat44_ei_in2out_node_fn_inline (vm, node, frame, 0 /* is_slow_path */,
  					 1);
  }
  
  VLIB_REGISTER_NODE (nat44_ei_in2out_output_node) = {
    .name = "nat44-ei-in2out-output",
    .vector_size = sizeof (u32),
    .format_trace = format_nat44_ei_in2out_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
  
    .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
    .error_strings = nat44_ei_in2out_error_strings,
  
    .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
  
    .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
  
    /* edit / add dispositions here */
    .next_nodes = {
      [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
      [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "interface-output",
      [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-output-slowpath",
      [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
      [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-interface-output",
    },
  };
  
  VLIB_NODE_FN (nat44_ei_in2out_slowpath_node)
  (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
  {
    return nat44_ei_in2out_node_fn_inline (vm, node, frame, 1 /* is_slow_path */,
  					 0);
  }
  
  VLIB_REGISTER_NODE (nat44_ei_in2out_slowpath_node) = {
    .name = "nat44-ei-in2out-slowpath",
    .vector_size = sizeof (u32),
    .format_trace = format_nat44_ei_in2out_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
  
    .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
    .error_strings = nat44_ei_in2out_error_strings,
  
    .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
  
    .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
  
    /* edit / add dispositions here */
    .next_nodes = {
      [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
      [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
      [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-slowpath",
      [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
      [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-ip4-lookup",
    },
  };
  
  VLIB_NODE_FN (nat44_ei_in2out_output_slowpath_node)
  (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
  {
    return nat44_ei_in2out_node_fn_inline (vm, node, frame, 1 /* is_slow_path */,
  					 1);
  }
  
  VLIB_REGISTER_NODE (nat44_ei_in2out_output_slowpath_node) = {
    .name = "nat44-ei-in2out-output-slowpath",
    .vector_size = sizeof (u32),
    .format_trace = format_nat44_ei_in2out_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
  
    .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
    .error_strings = nat44_ei_in2out_error_strings,
  
    .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
  
    .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
  
    /* edit / add dispositions here */
    .next_nodes = {
      [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
      [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "interface-output",
      [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-output-slowpath",
      [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
      [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-interface-output",
    },
  };
  
  VLIB_NODE_FN (nat44_ei_in2out_fast_node)
  (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
  {
    u32 n_left_from, *from, *to_next;
    u32 thread_index = vm->thread_index;
    nat44_ei_in2out_next_t next_index;
    nat44_ei_main_t *nm = &nat44_ei_main;
    int is_hairpinning = 0;
  
    from = vlib_frame_vector_args (frame);
    n_left_from = frame->n_vectors;
    next_index = node->cached_next_index;
  
    while (n_left_from > 0)
      {
        u32 n_left_to_next;
  
        vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  
        while (n_left_from > 0 && n_left_to_next > 0)
  	{
  	  u32 bi0;
  	  vlib_buffer_t *b0;
  	  u32 next0;
  	  u32 sw_if_index0;
  	  ip4_header_t *ip0;
  	  ip_csum_t sum0;
  	  u32 new_addr0, old_addr0;
  	  u16 old_port0, new_port0;
  	  udp_header_t *udp0;
  	  tcp_header_t *tcp0;
  	  icmp46_header_t *icmp0;
  	  u32 proto0;
  	  u32 rx_fib_index0;
  	  ip4_address_t sm0_addr;
  	  u16 sm0_port;
  	  u32 sm0_fib_index;
  	  u32 required_thread_index = thread_index;
  
  	  /* speculatively enqueue b0 to the current next frame */
  	  bi0 = from[0];
  	  to_next[0] = bi0;
  	  from += 1;
  	  to_next += 1;
  	  n_left_from -= 1;
  	  n_left_to_next -= 1;
  
  	  b0 = vlib_get_buffer (vm, bi0);
  	  next0 = NAT44_EI_IN2OUT_NEXT_LOOKUP;
  
  	  ip0 = vlib_buffer_get_current (b0);
  	  udp0 = ip4_next_header (ip0);
  	  tcp0 = (tcp_header_t *) udp0;
  	  icmp0 = (icmp46_header_t *) udp0;
  
  	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
  	  rx_fib_index0 =
  	    ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
  
  	  if (PREDICT_FALSE (ip0->ttl == 1))
  	    {
  	      vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
  	      icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
  					   ICMP4_time_exceeded_ttl_exceeded_in_transit,
  					   0);
  	      next0 = NAT44_EI_IN2OUT_NEXT_ICMP_ERROR;
  	      goto trace0;
  	    }
  
  	  proto0 = ip_proto_to_nat_proto (ip0->protocol);
  
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
  	    goto trace0;
  
  	  if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
  	    {
  	      next0 = nat44_ei_icmp_in2out (b0, ip0, icmp0, sw_if_index0,
  					    rx_fib_index0, node, next0, ~0, 0);
  	      goto trace0;
  	    }
  
  	  if (nat44_ei_static_mapping_match (
  		ip0->src_address, udp0->src_port, rx_fib_index0, proto0,
  		&sm0_addr, &sm0_port, &sm0_fib_index, 0, 0, 0))
  	    {
  	      b0->error = node->errors[NAT44_EI_IN2OUT_ERROR_NO_TRANSLATION];
  	      next0 = NAT44_EI_IN2OUT_NEXT_DROP;
  	      goto trace0;
  	    }
  
  	  new_addr0 = sm0_addr.as_u32;
  	  new_port0 = sm0_port;
  	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0_fib_index;
  	  old_addr0 = ip0->src_address.as_u32;
  	  ip0->src_address.as_u32 = new_addr0;
  
  	  sum0 = ip0->checksum;
  	  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
  				 ip4_header_t,
  				 src_address /* changed member */ );
  	  ip0->checksum = ip_csum_fold (sum0);
  
  	  if (PREDICT_FALSE (new_port0 != udp0->dst_port))
  	    {
  	      old_port0 = udp0->src_port;
  	      udp0->src_port = new_port0;
  
  	      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
  		{
  		  sum0 = tcp0->checksum;
  		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
  					 ip4_header_t,
  					 dst_address /* changed member */ );
  		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
  					 ip4_header_t /* cheat */ ,
  					 length /* changed member */ );
  		  mss_clamping (nm->mss_clamping, tcp0, &sum0);
  		  tcp0->checksum = ip_csum_fold (sum0);
  		}
  	      else if (udp0->checksum)
  		{
  		  sum0 = udp0->checksum;
  		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
  					 ip4_header_t,
  					 dst_address /* changed member */ );
  		  sum0 = ip_csum_update (sum0, old_port0, new_port0,
  					 ip4_header_t /* cheat */ ,
  					 length /* changed member */ );
  		  udp0->checksum = ip_csum_fold (sum0);
  		}
  	    }
  	  else
  	    {
  	      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
  		{
  		  sum0 = tcp0->checksum;
  		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
  					 ip4_header_t,
  					 dst_address /* changed member */ );
  		  mss_clamping (nm->mss_clamping, tcp0, &sum0);
  		  tcp0->checksum = ip_csum_fold (sum0);
  		}
  	      else if (udp0->checksum)
  		{
  		  sum0 = udp0->checksum;
  		  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
  					 ip4_header_t,
  					 dst_address /* changed member */ );
  		  udp0->checksum = ip_csum_fold (sum0);
  		}
  	    }
  
  	  /* Hairpinning */
  	  is_hairpinning = nat44_ei_hairpinning (
  	    vm, node, nm, thread_index, b0, ip0, udp0, tcp0, proto0,
  	    0 /* do_trace */, &required_thread_index);
  
  	  if (thread_index != required_thread_index)
  	    {
  	      vnet_buffer (b0)->snat.required_thread_index =
  		required_thread_index;
  	      next0 = NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF;
  	    }
  
  	trace0:
  	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
  			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
  	    {
  	      nat44_ei_in2out_trace_t *t =
  		vlib_add_trace (vm, node, b0, sizeof (*t));
  	      t->sw_if_index = sw_if_index0;
  	      t->next_index = next0;
  	      t->is_hairpinning = is_hairpinning;
  	    }
  
  	  if (next0 != NAT44_EI_IN2OUT_NEXT_DROP)
  	    {
  
  	      vlib_increment_simple_counter (
  		&nm->counters.fastpath.in2out.other, sw_if_index0,
  		vm->thread_index, 1);
  	    }
  
  	  /* 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);
      }
  
    return frame->n_vectors;
  }
  
  VLIB_REGISTER_NODE (nat44_ei_in2out_fast_node) = {
    .name = "nat44-ei-in2out-fast",
    .vector_size = sizeof (u32),
    .format_trace = format_nat44_ei_in2out_fast_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
  
    .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
    .error_strings = nat44_ei_in2out_error_strings,
  
    .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
  
    .n_next_nodes = NAT44_EI_IN2OUT_N_NEXT,
  
    /* edit / add dispositions here */
    .next_nodes = {
      [NAT44_EI_IN2OUT_NEXT_DROP] = "error-drop",
      [NAT44_EI_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
      [NAT44_EI_IN2OUT_NEXT_SLOW_PATH] = "nat44-ei-in2out-slowpath",
      [NAT44_EI_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
      [NAT44_EI_IN2OUT_NEXT_HAIRPINNING_HANDOFF] = "nat44-ei-in2out-hairpinning-handoff-ip4-lookup",
    },
  };
  
  VLIB_NODE_FN (nat44_ei_in2out_hairpinning_handoff_ip4_lookup_node)
  (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
  {
    return nat44_ei_hairpinning_handoff_fn_inline (
      vm, node, frame,
      nat44_ei_main.in2out_hairpinning_finish_ip4_lookup_node_fq_index);
  }
  
  VLIB_REGISTER_NODE (nat44_ei_in2out_hairpinning_handoff_ip4_lookup_node) = {
    .name = "nat44-ei-in2out-hairpinning-handoff-ip4-lookup",
    .vector_size = sizeof (u32),
    .n_errors = ARRAY_LEN(nat44_ei_hairpinning_handoff_error_strings),
    .error_strings = nat44_ei_hairpinning_handoff_error_strings,
    .format_trace = format_nat44_ei_hairpinning_handoff_trace,
  
    .n_next_nodes = 1,
  
    .next_nodes = {
      [0] = "error-drop",
    },
  };
  
  VLIB_NODE_FN (nat44_ei_in2out_hairpinning_handoff_interface_output_node)
  (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
  {
    return nat44_ei_hairpinning_handoff_fn_inline (
      vm, node, frame,
      nat44_ei_main.in2out_hairpinning_finish_interface_output_node_fq_index);
  }
  
  VLIB_REGISTER_NODE (nat44_ei_in2out_hairpinning_handoff_interface_output_node) = {
    .name = "nat44-ei-in2out-hairpinning-handoff-interface-output",
    .vector_size = sizeof (u32),
    .n_errors = ARRAY_LEN(nat44_ei_hairpinning_handoff_error_strings),
    .error_strings = nat44_ei_hairpinning_handoff_error_strings,
    .format_trace = format_nat44_ei_hairpinning_handoff_trace,
  
    .n_next_nodes = 1,
  
    .next_nodes = {
      [0] = "error-drop",
    },
  };
  
  static_always_inline int
  nat44_ei_in2out_hairpinning_finish_inline (vlib_main_t *vm,
  					   vlib_node_runtime_t *node,
  					   vlib_frame_t *frame)
  {
    u32 n_left_from, *from, *to_next;
    u32 thread_index = vm->thread_index;
    nat44_ei_in2out_next_t next_index;
    nat44_ei_main_t *nm = &nat44_ei_main;
    int is_hairpinning = 0;
  
    from = vlib_frame_vector_args (frame);
    n_left_from = frame->n_vectors;
    next_index = node->cached_next_index;
  
    while (n_left_from > 0)
      {
        u32 n_left_to_next;
  
        vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  
        while (n_left_from > 0 && n_left_to_next > 0)
  	{
  	  u32 bi0;
  	  vlib_buffer_t *b0;
  	  u32 next0;
  	  u32 sw_if_index0;
  	  ip4_header_t *ip0;
  	  udp_header_t *udp0;
  	  tcp_header_t *tcp0;
  	  icmp46_header_t *icmp0;
  	  u32 proto0;
  	  u32 required_thread_index = thread_index;
  
  	  /* speculatively enqueue b0 to the current next frame */
  	  bi0 = from[0];
  	  to_next[0] = bi0;
  	  from += 1;
  	  to_next += 1;
  	  n_left_from -= 1;
  	  n_left_to_next -= 1;
  
  	  b0 = vlib_get_buffer (vm, bi0);
  	  next0 = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP;
  
  	  ip0 = vlib_buffer_get_current (b0);
  	  udp0 = ip4_next_header (ip0);
  	  tcp0 = (tcp_header_t *) udp0;
  	  icmp0 = (icmp46_header_t *) udp0;
  
  	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
  	  proto0 = ip_proto_to_nat_proto (ip0->protocol);
  
  	  switch (proto0)
  	    {
  	    case NAT_PROTOCOL_TCP:
  	      // fallthrough
  	    case NAT_PROTOCOL_UDP:
  	      is_hairpinning = nat44_ei_hairpinning (
  		vm, node, nm, thread_index, b0, ip0, udp0, tcp0, proto0,
  		0 /* do_trace */, &required_thread_index);
  	      break;
  	    case NAT_PROTOCOL_ICMP:
  	      is_hairpinning = (0 == nat44_ei_icmp_hairpinning (
  				       nm, b0, thread_index, ip0, icmp0,
  				       &required_thread_index));
  	      break;
  	    case NAT_PROTOCOL_OTHER:
  	      // this should never happen
  	      next0 = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP;
  	      break;
  	    }
  
  	  if (thread_index != required_thread_index)
  	    {
  	      // but we already did a handoff ...
  	      next0 = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP;
  	    }
  
  	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
  			     (b0->flags & VLIB_BUFFER_IS_TRACED)))
  	    {
  	      nat44_ei_in2out_trace_t *t =
  		vlib_add_trace (vm, node, b0, sizeof (*t));
  	      t->sw_if_index = sw_if_index0;
  	      t->next_index = next0;
  	      t->is_hairpinning = is_hairpinning;
  	    }
  
  	  if (next0 != NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP)
  	    {
  	      vlib_increment_simple_counter (
  		&nm->counters.fastpath.in2out.other, sw_if_index0,
  		vm->thread_index, 1);
  	    }
  
  	  /* 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);
      }
  
    return frame->n_vectors;
  }
  
  VLIB_NODE_FN (nat44_ei_in2out_hairpinning_finish_ip4_lookup_node)
  (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
  {
    return nat44_ei_in2out_hairpinning_finish_inline (vm, node, frame);
  }
  
  VLIB_REGISTER_NODE (nat44_ei_in2out_hairpinning_finish_ip4_lookup_node) = {
    .name = "nat44-ei-in2out-hairpinning-finish-ip4-lookup",
    .vector_size = sizeof (u32),
    .format_trace = format_nat44_ei_in2out_fast_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
  
    .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
    .error_strings = nat44_ei_in2out_error_strings,
  
    .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
  
    .n_next_nodes = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_N_NEXT,
  
    /* edit / add dispositions here */
    .next_nodes = {
      [NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP] = "error-drop",
      [NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP] = "ip4-lookup",
    },
  };
  
  VLIB_NODE_FN (nat44_ei_in2out_hairpinning_finish_interface_output_node)
  (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
  {
    return nat44_ei_in2out_hairpinning_finish_inline (vm, node, frame);
  }
  
  VLIB_REGISTER_NODE (nat44_ei_in2out_hairpinning_finish_interface_output_node) = {
    .name = "nat44-ei-in2out-hairpinning-finish-interface-output",
    .vector_size = sizeof (u32),
    .format_trace = format_nat44_ei_in2out_fast_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
  
    .n_errors = ARRAY_LEN(nat44_ei_in2out_error_strings),
    .error_strings = nat44_ei_in2out_error_strings,
  
    .runtime_data_bytes = sizeof (nat44_ei_runtime_t),
  
    .n_next_nodes = NAT44_EI_IN2OUT_HAIRPINNING_FINISH_N_NEXT,
  
    /* edit / add dispositions here */
    .next_nodes = {
      [NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_DROP] = "error-drop",
      [NAT44_EI_IN2OUT_HAIRPINNING_FINISH_NEXT_LOOKUP] = "interface-output",
    },
  };
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  