src/cmake/VPPConfig.cmake


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# 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.

get_filename_component(CMAKE_CURRENT_LIST_DIR ${CMAKE_CURRENT_LIST_FILE} PATH)

find_path(VPP_INCLUDE_DIR PATH_SUFFIXES NAMES vppinfra/clib.h)
find_program(VPP_APIGEN vppapigen)

if(VPP_INCLUDE_DIR AND VPP_APIGEN)
  include_directories (${VPP_INCLUDE_DIR})
else()
  message(FATAL_ERROR "VPP headers, libraries and/or tools not found")
endif()

set(VPP_EXTERNAL_PROJECT 1)

include(CheckCCompilerFlag)

check_c_compiler_flag("-Wno-address-of-packed-member" compiler_flag_no_address_of_packed_member)
if (compiler_flag_no_address_of_packed_member)
  add_definitions(-Wno-address-of-packed-member)
endif()

include(CheckCCompilerFlag)
include(${CMAKE_CURRENT_LIST_DIR}/cpu.cmake)
include(${CMAKE_CURRENT_LIST_DIR}/api.cmake)
include(${CMAKE_CURRENT_LIST_DIR}/library.cmake)
include(${CMAKE_CURRENT_LIST_DIR}/plugin.cmake)
include(${CMAKE_CURRENT_LIST_DIR}/pack.cmake)
/*
 * Copyright (c) 2016 Intel 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 anated to in writing, software
 * distributed under the License is distributed on an "POD IS" BPODIS,
 * 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.
 */


#include <vnet/fib/ip4_fib.h>

#include <kubeproxy/kp.h>
#include <kubeproxy/kphash.h>

#define foreach_kp_error \
 _(NONE, "no error") \
 _(PROTO_NOT_SUPPORTED, "protocol not supported")

typedef enum {
#define _(sym,str) KP_ERROR_##sym,
  foreach_kp_error
#undef _
    KP_N_ERROR,
} kp_error_t;

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

typedef struct {
  u32 vip_index;
  u32 pod_index;
} kp_trace_t;

typedef struct {
  u32 vip_index;
  u32 node_port;
} kp_nodeport_trace_t;

typedef struct {
  u32 rx_sw_if_index;
  u32 next_index;
} kp_nat_trace_t;

u8 *
format_kp_trace (u8 * s, va_list * args)
{
  kp_main_t *kpm = &kp_main;
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  kp_trace_t *t = va_arg (*args, kp_trace_t *);
  if (pool_is_free_index(kpm->vips, t->vip_index)) {
      s = format(s, "kp vip[%d]: This VIP was freed since capture\n");
  } else {
      s = format(s, "kp vip[%d]: %U\n", t->vip_index, format_kp_vip, &kpm->vips[t->vip_index]);
  }
  if (pool_is_free_index(kpm->pods, t->pod_index)) {
      s = format(s, "  kp pod[%d]: This POD was freed since capture");
  } else {
      s = format(s, "  kp pod[%d]: %U", t->pod_index, format_kp_pod, &kpm->pods[t->pod_index]);
  }
  return s;
}

u8 *
format_kp_nat_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 *);
  kp_nat_trace_t *t = va_arg (*args, kp_nat_trace_t *);

  s = format(s, "kp nat: rx_sw_if_index = %d, next_index = %d",
	     t->rx_sw_if_index, t->next_index);

  return s;
}

kp_hash_t *kp_get_sticky_table(u32 thread_index)
{
  kp_main_t *kpm = &kp_main;
  kp_hash_t *sticky_ht = kpm->per_cpu[thread_index].sticky_ht;
  //Check if size changed
  if (PREDICT_FALSE(sticky_ht && (kpm->per_cpu_sticky_buckets != kp_hash_nbuckets(sticky_ht))))
    {
      //Dereference everything in there
      kp_hash_bucket_t *b;
      u32 i;
      kp_hash_foreach_entry(sticky_ht, b, i) {
	vlib_refcount_add(&kpm->pod_refcount, thread_index, b->value[i], -1);
	vlib_refcount_add(&kpm->pod_refcount, thread_index, 0, 1);
      }

      kp_hash_free(sticky_ht);
      sticky_ht = NULL;
    }

  //Create if necessary
  if (PREDICT_FALSE(sticky_ht == NULL)) {
    kpm->per_cpu[thread_index].sticky_ht = kp_hash_alloc(kpm->per_cpu_sticky_buckets, kpm->flow_timeout);
    sticky_ht = kpm->per_cpu[thread_index].sticky_ht;
    clib_warning("Regenerated sticky table %p", sticky_ht);
  }

  ASSERT(sticky_ht);

  //Update timeout
  sticky_ht->timeout = kpm->flow_timeout;
  return sticky_ht;
}

u64
kp_node_get_other_ports4(ip4_header_t *ip40)
{
  return 0;
}

u64
kp_node_get_other_ports6(ip6_header_t *ip60)
{
  return 0;
}

static_always_inline u32
kp_node_get_hash(vlib_buffer_t *p, u8 is_input_v4)
{
  u32 hash;
  if (is_input_v4)
    {
      ip4_header_t *ip40;
      u64 ports;
      ip40 = vlib_buffer_get_current (p);
      if (PREDICT_TRUE (ip40->protocol == IP_PROTOCOL_TCP ||
		       ip40->protocol == IP_PROTOCOL_UDP))
	ports = ((u64)((udp_header_t *)(ip40 + 1))->src_port << 16) |
	  ((u64)((udp_header_t *)(ip40 + 1))->dst_port);
      else
	ports = kp_node_get_other_ports4(ip40);

      hash = kp_hash_hash(*((u64 *)&ip40->address_pair), ports,
			  0, 0, 0);
    }
  else
    {
      ip6_header_t *ip60;
      ip60 = vlib_buffer_get_current (p);
      u64 ports;
      if (PREDICT_TRUE (ip60->protocol == IP_PROTOCOL_TCP ||
			ip60->protocol == IP_PROTOCOL_UDP))
	ports = ((u64)((udp_header_t *)(ip60 + 1))->src_port << 16) |
	((u64)((udp_header_t *)(ip60 + 1))->dst_port);
      else
	ports = kp_node_get_other_ports6(ip60);

      hash = kp_hash_hash(ip60->src_address.as_u64[0],
			  ip60->src_address.as_u64[1],
			  ip60->dst_address.as_u64[0],
			  ip60->dst_address.as_u64[1],
			  ports);
    }
  return hash;
}

static_always_inline uword
kp_node_fn (vlib_main_t * vm,
         vlib_node_runtime_t * node, vlib_frame_t * frame,
         u8 is_input_v4, //Compile-time parameter stating that is input is v4 (or v6)
         u8 is_nat_v4) //Compile-time parameter stating that is NAT is v4 (or v6)
{
  kp_main_t *kpm = &kp_main;
  u32 n_left_from, *from, next_index, *to_next, n_left_to_next;
  u32 thread_index = vlib_get_thread_index();
  u32 kp_time = kp_hash_time_now(vm);

  kp_hash_t *sticky_ht = kp_get_sticky_table(thread_index);
  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;

  u32 nexthash0 = 0;
  if (PREDICT_TRUE(n_left_from > 0))
    nexthash0 = kp_node_get_hash(vlib_get_buffer (vm, from[0]), is_input_v4);

  while (n_left_from > 0)
  {
    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 pi0;
      vlib_buffer_t *p0;
      kp_vip_t *vip0;
      u32 podindex0;
      u32 available_index0;
      u8 counter = 0;
      u32 hash0 = nexthash0;

      if (PREDICT_TRUE(n_left_from > 1))
	{
	  vlib_buffer_t *p1 = vlib_get_buffer (vm, from[1]);
	  //Compute next hash and prefetch bucket
	  nexthash0 = kp_node_get_hash(p1, is_input_v4);
	  kp_hash_prefetch_bucket(sticky_ht, nexthash0);
	  //Prefetch for encap, next
	  CLIB_PREFETCH (vlib_buffer_get_current(p1) - 64, 64, STORE);
	}

      if (PREDICT_TRUE(n_left_from > 2))
	{
	  vlib_buffer_t *p2;
	  p2 = vlib_get_buffer(vm, from[2]);
	  /* prefetch packet header and data */
	  vlib_prefetch_buffer_header(p2, STORE);
	  CLIB_PREFETCH (vlib_buffer_get_current(p2), 64, STORE);
	}

      pi0 = to_next[0] = from[0];
      from += 1;
      n_left_from -= 1;
      to_next += 1;
      n_left_to_next -= 1;

      p0 = vlib_get_buffer (vm, pi0);
      vip0 = pool_elt_at_index (kpm->vips,
				vnet_buffer (p0)->ip.adj_index[VLIB_TX]);

      kp_hash_get(sticky_ht, hash0, vnet_buffer (p0)->ip.adj_index[VLIB_TX],
		  kp_time, &available_index0, &podindex0);

      if (PREDICT_TRUE(podindex0 != ~0))
	{
	  //Found an existing entry
	  counter = KP_VIP_COUNTER_NEXT_PACKET;
	}
      else if (PREDICT_TRUE(available_index0 != ~0))
	{
	  //There is an available slot for a new flow
	  podindex0 = vip0->new_flow_table[hash0 & vip0->new_flow_table_mask].pod_index;
	  counter = KP_VIP_COUNTER_FIRST_PACKET;
	  counter = (podindex0 == 0)?KP_VIP_COUNTER_NO_SERVER:counter;

	  //Dereference previously used
	  vlib_refcount_add(&kpm->pod_refcount, thread_index,
			    kp_hash_available_value(sticky_ht, hash0, available_index0), -1);
	  vlib_refcount_add(&kpm->pod_refcount, thread_index,
			    podindex0, 1);

	  //Add sticky entry
	  //Note that when there is no POD configured, an entry is configured anyway.
	  //But no configured POD is not something that should happen
	  kp_hash_put(sticky_ht, hash0, podindex0,
		      vnet_buffer (p0)->ip.adj_index[VLIB_TX],
		      available_index0, kp_time);
	}
      else
	{
	  //Could not store new entry in the table
	  podindex0 = vip0->new_flow_table[hash0 & vip0->new_flow_table_mask].pod_index;
	  counter = KP_VIP_COUNTER_UNTRACKED_PACKET;
	}

      vlib_increment_simple_counter(&kpm->vip_counters[counter],
				    thread_index,
				    vnet_buffer (p0)->ip.adj_index[VLIB_TX],
				    1);
      //Now let's do NAT
      {
	udp_header_t *port0;

	if ( (is_input_v4==1) && (is_nat_v4==1) )  /* NAT44 */
	  {
	    ip4_header_t *ip40;
	    ip40 = vlib_buffer_get_current(p0);
	    port0 = (udp_header_t *)(ip40 + 1);
	    ip40->dst_address = kpm->pods[podindex0].address.ip4;
	    ip40->checksum = ip4_header_checksum (ip40);
	  }
	else if ( (is_input_v4==1) && (is_nat_v4==0) )  /* NAT46 */
	  {
	    /* TBD */
	    u16 len0 = 0;
	    ip4_header_t *ip40;
	    ip40 = vlib_buffer_get_current(p0);
	    len0 = clib_net_to_host_u16(ip40->length);

	    vlib_buffer_advance(p0, (-sizeof(ip6_header_t)+sizeof(ip4_header_t)) );
	    ip6_header_t *ip60;
	    ip60 = vlib_buffer_get_current(p0);
	    port0 = (udp_header_t *)(ip60 + 1);
	    ip60->payload_length = len0 - sizeof(ip4_header_t);
	    ip60->dst_address = kpm->pods[podindex0].address.ip6;
	  }
	else if ( (is_input_v4==0) && (is_nat_v4==0) )  /* NAT66 */
	  {
	    ip6_header_t *ip60;
	    ip60 = vlib_buffer_get_current(p0);
	    port0 = (udp_header_t *)(ip60 + 1);
	    ip60->dst_address = kpm->pods[podindex0].address.ip6;
	  }
	else /* NAT64 */
	  {
	    /* TBD */
	    u16 len0 = 0;
	    ip6_header_t *ip60;
	    ip60 = vlib_buffer_get_current(p0);
	    len0 = clib_net_to_host_u16(ip60->payload_length);

	    vlib_buffer_advance(p0, (sizeof(ip6_header_t)-sizeof(ip4_header_t)) );
	    ip4_header_t *ip40;
	    ip40 = vlib_buffer_get_current(p0);
	    port0 = (udp_header_t *)(ip40 + 1);
	    ip40->length = len0 + sizeof(ip4_header_t);
	    ip40->dst_address = kpm->pods[podindex0].address.ip4;
	    ip40->checksum = ip4_header_checksum (ip40);
	  }

	port0->dst_port = vip0->target_port;
      }

      if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
	{
	  kp_trace_t *tr = vlib_add_trace (vm, node, p0, sizeof (*tr));
	  tr->pod_index = podindex0;
	  tr->vip_index = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
	}

      //Enqueue to next
      //Note that this is going to error if podindex0 == 0
      vnet_buffer (p0)->ip.adj_index[VLIB_TX] = kpm->pods[podindex0].dpo.dpoi_index;
      vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
				       n_left_to_next, pi0,
				       kpm->pods[podindex0].dpo.dpoi_next_node);
    }
    vlib_put_next_frame (vm, node, next_index, n_left_to_next);
  }

  return frame->n_vectors;
}

u8 *
format_nodeport_kp_trace (u8 * s, va_list * args)
{
  kp_main_t *kpm = &kp_main;
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  kp_nodeport_trace_t *t = va_arg (*args, kp_nodeport_trace_t *);
  if (pool_is_free_index(kpm->vips, t->vip_index)) {
      s = format(s, "kp vip[%d]: This VIP was freed since capture\n");
  } else {
      s = format(s, "kp vip[%d]: %U\n", t->vip_index, format_kp_vip, &kpm->vips[t->vip_index]);
  }

  s = format(s, "  kp node_port: %d", t->node_port);

  return s;
}
static uword
kp_nodeport_node_fn (vlib_main_t * vm,
                     vlib_node_runtime_t * node,
		     vlib_frame_t * frame,
		     u8 is_input_v4)
{
  kp_main_t *kpm = &kp_main;
  u32 n_left_from, *from, next_index, *to_next, n_left_to_next;

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;


  while (n_left_from > 0)
  {
    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 pi0;
      vlib_buffer_t *p0;
      udp_header_t * udp_0;
      uword * entry0;
      u32 next0 = KP_NODEPORT_NEXT_DROP;


      if (PREDICT_TRUE(n_left_from > 1))
	{
	  vlib_buffer_t *p1 = vlib_get_buffer (vm, from[1]);
	  //Prefetch for encap, next
	  CLIB_PREFETCH (vlib_buffer_get_current(p1) - 64, 64, STORE);
	}

      if (PREDICT_TRUE(n_left_from > 2))
	{
	  vlib_buffer_t *p2;
	  p2 = vlib_get_buffer(vm, from[2]);
	  /* prefetch packet header and data */
	  vlib_prefetch_buffer_header(p2, STORE);
	  CLIB_PREFETCH (vlib_buffer_get_current(p2), 64, STORE);
	}

      pi0 = to_next[0] = from[0];
      from += 1;
      n_left_from -= 1;
      to_next += 1;
      n_left_to_next -= 1;

      p0 = vlib_get_buffer (vm, pi0);

      if (is_input_v4==1)
	{
	  ip4_header_t *ip40;
	  vlib_buffer_advance
	    (p0, -(word)(sizeof(udp_header_t)+sizeof(ip4_header_t)));
	  ip40 = vlib_buffer_get_current(p0);
	  udp_0 = (udp_header_t *)(ip40 + 1);
	}
      else
	{
	  ip6_header_t *ip60;
	  vlib_buffer_advance
	    (p0, -(word)(sizeof(udp_header_t)+sizeof(ip6_header_t)));
	  ip60 = vlib_buffer_get_current(p0);
	  udp_0 = (udp_header_t *)(ip60 + 1);
	}

      entry0 = hash_get_mem(kpm->nodeport_by_key, &(udp_0->dst_port));


      if (is_input_v4==1)
	{
          next0 = KP_NODEPORT_NEXT_IP4_NAT4;
	}
      else
	{
	  next0 = KP_NODEPORT_NEXT_IP6_NAT6;
	}

      if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
	{
	  kp_nodeport_trace_t *tr = vlib_add_trace (vm, node,
						    p0, sizeof (*tr));
	  tr->vip_index = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
	  tr->node_port = (u32)clib_net_to_host_u16(udp_0->dst_port);
	}

      //Enqueue to next
      vnet_buffer(p0)->ip.adj_index[VLIB_TX] = entry0[0];
      vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
				       n_left_to_next, pi0, next0);
    }
    vlib_put_next_frame (vm, node, next_index, n_left_to_next);
  }

  return frame->n_vectors;

}

/**
 * @brief Match NAT4 static mapping.
 *
 * @param sm          NAT main.
 * @param match       Address and port to match.
 * @param mapping     External or local address and port of the matched mapping.
 *
 * @returns 0 if match found otherwise 1.
 */
int kp_nat4_mapping_match (kp_main_t *kpm,
                           kp_snat4_key_t match,
			   kp_snat4_key_t * mapping)
{
  clib_bihash_kv_8_8_t kv, value;
  kp_snat_mapping_t *m;
  kp_snat4_key_t m_key;
  clib_bihash_8_8_t *mapping_hash = &kpm->mapping_by_pod;

  m_key.addr = match.addr;
  m_key.port = match.port;
  m_key.protocol = match.protocol;
  m_key.fib_index = match.fib_index;

  kv.key = m_key.as_u64;

  if (clib_bihash_search_8_8 (mapping_hash, &kv, &value))
    {
      return 1;
    }

  m = pool_elt_at_index (kpm->snat_mappings, value.value);

  if (m->svr_type == KP_SVR_TYPE_VIP_PORT)
    {
      mapping->addr = m->vip.ip4;
      mapping->port = clib_host_to_net_u16 (m->port);
      mapping->fib_index = m->fib_index;
      mapping->protocol = match.protocol;
    }
  else if (m->svr_type == KP_SVR_TYPE_NODEIP_PORT)
    {
      mapping->addr = m->node_ip.ip4;
      mapping->port = clib_host_to_net_u16 (m->node_port);
      mapping->fib_index = m->fib_index;
      mapping->protocol = match.protocol;
    }

  return 0;
}

static uword
kp_nat4_in2out_node_fn (vlib_main_t * vm,
                        vlib_node_runtime_t * node,
                        vlib_frame_t * frame)
{
  u32 n_left_from, * from, * to_next;
  kp_nat4_in2out_next_t next_index;
  u32 pkts_processed = 0;
  kp_main_t *kpm = &kp_main;
  u32 stats_node_index;

  stats_node_index = kp_nat4_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;
          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;
          kp_snat4_key_t key0, sm0;
          u32 proto0;
          u32 rx_fib_index0;

          /* 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 = KP_NAT4_IN2OUT_NEXT_LOOKUP;

          ip0 = vlib_buffer_get_current (b0);
          udp0 = ip4_next_header (ip0);
          tcp0 = (tcp_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);

          proto0 = kp_ip_proto_to_nat_proto (ip0->protocol);

          if (PREDICT_FALSE (proto0 == ~0))
              goto trace0;

          key0.addr = ip0->src_address;
          key0.protocol = proto0;
          key0.port = udp0->src_port;
          key0.fib_index = rx_fib_index0;

          if (kp_nat4_mapping_match (kpm, key0, &sm0))
            {
              next0= KP_NAT4_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))
            {
              if (PREDICT_TRUE(proto0 == KP_NAT_PROTOCOL_TCP))
                {
                  old_port0 = tcp0->src_port;
                  tcp0->src_port = new_port0;

                  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 */);
                  tcp0->checksum = ip_csum_fold(sum0);
                }
              else
                {
                  old_port0 = udp0->src_port;
                  udp0->src_port = new_port0;
                  udp0->checksum = 0;
                }
            }
          else
            {
              if (PREDICT_TRUE(proto0 == KP_NAT_PROTOCOL_TCP))
                {
                  sum0 = tcp0->checksum;
                  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
                                         ip4_header_t,
                                         dst_address /* changed member */);
                  tcp0->checksum = ip_csum_fold(sum0);
                }
            }

        trace0:
          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)
                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
            {
              kp_nat_trace_t *t =
                 vlib_add_trace (vm, node, b0, sizeof (*t));
              t->rx_sw_if_index = sw_if_index0;
              t->next_index = next0;
            }

          pkts_processed += next0 != KP_NAT4_IN2OUT_NEXT_DROP;

          /* verify speculative enqueue, maybe switch current next frame */
	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
					   to_next, n_left_to_next,
					   bi0, next0);
	}

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  vlib_node_increment_counter (vm, stats_node_index,
                               KP_NAT_IN2OUT_ERROR_IN2OUT_PACKETS,
                               pkts_processed);
  return frame->n_vectors;
}

static uword
kp6_nat6_node_fn (vlib_main_t * vm,
         vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  return kp_node_fn(vm, node, frame, 0, 0);
}

static uword
kp6_nat4_node_fn (vlib_main_t * vm,
         vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  return kp_node_fn(vm, node, frame, 0, 1);
}

static uword
kp4_nat6_node_fn (vlib_main_t * vm,
         vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  return kp_node_fn(vm, node, frame, 1, 0);
}

static uword
kp4_nat4_node_fn (vlib_main_t * vm,
         vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  return kp_node_fn(vm, node, frame, 1, 1);
}

VLIB_REGISTER_NODE (kp6_nat6_node) =
{
  .function = kp6_nat6_node_fn,
  .name = "kp6-nat6",
  .vector_size = sizeof (u32),
  .format_trace = format_kp_trace,

  .n_errors = KP_N_ERROR,
  .error_strings = kp_error_strings,

  .n_next_nodes = KP_N_NEXT,
  .next_nodes =
  {
      [KP_NEXT_DROP] = "error-drop"
  },
};

VLIB_REGISTER_NODE (kp6_nat4_node) =
{
  .function = kp6_nat4_node_fn,
  .name = "kp6-nat4",
  .vector_size = sizeof (u32),
  .format_trace = format_kp_trace,

  .n_errors = KP_N_ERROR,
  .error_strings = kp_error_strings,

  .n_next_nodes = KP_N_NEXT,
  .next_nodes =
  {
      [KP_NEXT_DROP] = "error-drop"
  },
};

VLIB_REGISTER_NODE (kp4_nat6_node) =
{
  .function = kp4_nat6_node_fn,
  .name = "kp4-nat6",
  .vector_size = sizeof (u32),
  .format_trace = format_kp_trace,

  .n_errors = KP_N_ERROR,
  .error_strings = kp_error_strings,

  .n_next_nodes = KP_N_NEXT,
  .next_nodes =
  {
      [KP_NEXT_DROP] = "error-drop"
  },
};

VLIB_REGISTER_NODE (kp4_nat4_node) =
{
  .function = kp4_nat4_node_fn,
  .name = "kp4-nat4",
  .vector_size = sizeof (u32),
  .format_trace = format_kp_trace,

  .n_errors = KP_N_ERROR,
  .error_strings = kp_error_strings,

  .n_next_nodes = KP_N_NEXT,
  .next_nodes =
  {
      [KP_NEXT_DROP] = "error-drop"
  },
};

static uword
kp4_nodeport_node_fn (vlib_main_t * vm,
                      vlib_node_runtime_t * node,
		      vlib_frame_t * frame)
{
  return kp_nodeport_node_fn(vm, node, frame, 1);
}

static uword
kp6_nodeport_node_fn (vlib_main_t * vm,
                      vlib_node_runtime_t * node,
		      vlib_frame_t * frame)
{
  return kp_nodeport_node_fn(vm, node, frame, 0);
}

VLIB_REGISTER_NODE (kp4_nodeport_node) =
{
  .function = kp4_nodeport_node_fn,
  .name = "kp4-nodeport",
  .vector_size = sizeof (u32),
  .format_trace = format_nodeport_kp_trace,

  .n_errors = KP_N_ERROR,
  .error_strings = kp_error_strings,

  .n_next_nodes = KP_NODEPORT_N_NEXT,
  .next_nodes =
  {
      [KP_NODEPORT_NEXT_IP4_NAT4] = "kp4-nat4",
      [KP_NODEPORT_NEXT_IP4_NAT6] = "kp4-nat6",
      [KP_NODEPORT_NEXT_IP6_NAT4] = "kp6-nat4",
      [KP_NODEPORT_NEXT_IP6_NAT6] = "kp6-nat6",
      [KP_NODEPORT_NEXT_DROP] = "error-drop",
  },
};

VLIB_REGISTER_NODE (kp6_nodeport_node) =
{
  .function = kp6_nodeport_node_fn,
  .name = "kp6-nodeport",
  .vector_size = sizeof (u32),
  .format_trace = format_nodeport_kp_trace,

  .n_errors = KP_N_ERROR,
  .error_strings = kp_error_strings,

  .n_next_nodes = KP_NODEPORT_N_NEXT,
  .next_nodes =
  {
      [KP_NODEPORT_NEXT_IP4_NAT4] = "kp4-nat4",
      [KP_NODEPORT_NEXT_IP4_NAT6] = "kp4-nat6",
      [KP_NODEPORT_NEXT_IP6_NAT4] = "kp6-nat4",
      [KP_NODEPORT_NEXT_IP6_NAT6] = "kp6-nat6",
      [KP_NODEPORT_NEXT_DROP] = "error-drop",
  },
};

VNET_FEATURE_INIT (kp_nat4_in2out_node_fn, static) =
{
  .arc_name = "ip4-unicast",
  .node_name = "kp-nat4-in2out",
  .runs_before = VNET_FEATURES ("ip4-lookup"),
};

VLIB_REGISTER_NODE (kp_nat4_in2out_node) =
{
  .function = kp_nat4_in2out_node_fn,
  .name = "kp-nat4-in2out",
  .vector_size = sizeof (u32),
  .format_trace = format_kp_nat_trace,

  .n_errors = KP_N_ERROR,
  .error_strings = kp_error_strings,

  .n_next_nodes = KP_NAT4_IN2OUT_N_NEXT,
  .next_nodes =
  {
      [KP_NAT4_IN2OUT_NEXT_DROP] = "error-drop",
      [KP_NAT4_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
  },
};