ip4_map_t.c

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/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "map.h"

#include "../ip/ip_frag.h"

#define IP4_MAP_T_DUAL_LOOP 1

typedef enum {
  IP4_MAPT_NEXT_MAPT_TCP_UDP,
  IP4_MAPT_NEXT_MAPT_ICMP,
  IP4_MAPT_NEXT_MAPT_FRAGMENTED,
  IP4_MAPT_NEXT_DROP,
  IP4_MAPT_N_NEXT
} ip4_mapt_next_t;

typedef enum {
  IP4_MAPT_ICMP_NEXT_IP6_LOOKUP,
  IP4_MAPT_ICMP_NEXT_IP6_FRAG,
  IP4_MAPT_ICMP_NEXT_DROP,
  IP4_MAPT_ICMP_N_NEXT
} ip4_mapt_icmp_next_t;

typedef enum {
  IP4_MAPT_TCP_UDP_NEXT_IP6_LOOKUP,
  IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG,
  IP4_MAPT_TCP_UDP_NEXT_DROP,
  IP4_MAPT_TCP_UDP_N_NEXT
} ip4_mapt_tcp_udp_next_t;

typedef enum {
  IP4_MAPT_FRAGMENTED_NEXT_IP6_LOOKUP,
  IP4_MAPT_FRAGMENTED_NEXT_IP6_FRAG,
  IP4_MAPT_FRAGMENTED_NEXT_DROP,
  IP4_MAPT_FRAGMENTED_N_NEXT
} ip4_mapt_fragmented_next_t;

//This is used to pass information within the buffer data.
//Buffer structure being too small to contain big structures like this.
typedef CLIB_PACKED(struct {
  ip6_address_t daddr;
  ip6_address_t saddr;
  //IPv6 header + Fragmentation header will be here
  //sizeof(ip6) + sizeof(ip_frag) - sizeof(ip4)
  u8 unused[28];
}) ip4_mapt_pseudo_header_t;

#define frag_id_4to6(id) (id)

//TODO: Find the right place in memory for this.
static u8 icmp_to_icmp6_updater_pointer_table[] =
    { 0, 1, 4, 4,~0,
     ~0,~0,~0, 7, 6,
     ~0,~0, 8, 8, 8,
      8, 24, 24, 24, 24 };


static_always_inline int
ip4_map_fragment_cache (ip4_header_t *ip4, u16 port)
{
  u32 *ignore = NULL;
  map_ip4_reass_lock();
  map_ip4_reass_t *r = map_ip4_reass_get(ip4->src_address.as_u32, ip4->dst_address.as_u32,
                                         ip4->fragment_id,
                                         (ip4->protocol == IP_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP6 : ip4->protocol,
                                             &ignore);
  if (r)
    r->port = port;

  map_ip4_reass_unlock();
  return !r;
}

static_always_inline i32
ip4_map_fragment_get_port (ip4_header_t *ip4)
{
  u32 *ignore = NULL;
  map_ip4_reass_lock();
  map_ip4_reass_t *r = map_ip4_reass_get(ip4->src_address.as_u32, ip4->dst_address.as_u32,
                                         ip4->fragment_id,
                                         (ip4->protocol == IP_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP6 : ip4->protocol,
                                             &ignore);
  i32 ret = r?r->port:-1;
  map_ip4_reass_unlock();
  return ret;
}


/* Statelessly translates an ICMP packet into ICMPv6.
 *
 * Warning: The checksum will need to be recomputed.
 *
 */
static_always_inline int
ip4_icmp_to_icmp6_in_place (icmp46_header_t *icmp, u32 icmp_len,
                            i32 *receiver_port, ip4_header_t **inner_ip4)
{
  *inner_ip4 = NULL;
  switch (icmp->type) {
    case ICMP4_echo_reply:
      *receiver_port = ((u16 *)icmp)[2];
      icmp->type = ICMP6_echo_reply;
      break;
    case ICMP4_echo_request:
      *receiver_port = ((u16 *)icmp)[2];
      icmp->type = ICMP6_echo_request;
      break;
    case ICMP4_destination_unreachable:
      *inner_ip4 = (ip4_header_t *)(((u8 *) icmp) + 8);
      *receiver_port = ip4_get_port(*inner_ip4, MAP_SENDER, icmp_len - 8);

      switch (icmp->code) {
        case ICMP4_destination_unreachable_destination_unreachable_net: //0
        case ICMP4_destination_unreachable_destination_unreachable_host: //1
          icmp->type = ICMP6_destination_unreachable;
          icmp->code = ICMP6_destination_unreachable_no_route_to_destination;
          break;
        case ICMP4_destination_unreachable_protocol_unreachable: //2
          icmp->type = ICMP6_parameter_problem;
          icmp->code = ICMP6_parameter_problem_unrecognized_next_header;
          break;
        case ICMP4_destination_unreachable_port_unreachable: //3
          icmp->type = ICMP6_destination_unreachable;
          icmp->code = ICMP6_destination_unreachable_port_unreachable;
          break;
        case ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set: //4
          icmp->type = ICMP6_packet_too_big;
          icmp->code = 0;
          {
            u32 advertised_mtu = clib_net_to_host_u32(*((u32 *)(icmp + 1)));
            if (advertised_mtu)
              advertised_mtu += 20;
            else
              advertised_mtu = 1000; //FIXME ! (RFC 1191 - plateau value)

            //FIXME: = minimum(advertised MTU+20, MTU_of_IPv6_nexthop, (MTU_of_IPv4_nexthop)+20)
            *((u32 *)(icmp + 1)) = clib_host_to_net_u32(advertised_mtu);
          }
          break;

        case ICMP4_destination_unreachable_source_route_failed: //5
        case ICMP4_destination_unreachable_destination_network_unknown: //6
        case ICMP4_destination_unreachable_destination_host_unknown: //7
        case ICMP4_destination_unreachable_source_host_isolated: //8
        case ICMP4_destination_unreachable_network_unreachable_for_type_of_service: //11
        case ICMP4_destination_unreachable_host_unreachable_for_type_of_service: //12
          icmp->type = ICMP6_destination_unreachable;
          icmp->code = ICMP6_destination_unreachable_no_route_to_destination;
          break;
        case ICMP4_destination_unreachable_network_administratively_prohibited: //9
        case ICMP4_destination_unreachable_host_administratively_prohibited: //10
        case ICMP4_destination_unreachable_communication_administratively_prohibited: //13
        case ICMP4_destination_unreachable_precedence_cutoff_in_effect: //15
          icmp->type = ICMP6_destination_unreachable;
          icmp->code = ICMP6_destination_unreachable_destination_administratively_prohibited;
          break;
        case ICMP4_destination_unreachable_host_precedence_violation: //14
        default:
          return -1;
      }
      break;

    case ICMP4_time_exceeded: //11
      *inner_ip4 = (ip4_header_t *)(((u8 *) icmp) + 8);
      *receiver_port = ip4_get_port(*inner_ip4, MAP_SENDER, icmp_len - 8);
      icmp->type = ICMP6_time_exceeded;
      //icmp->code = icmp->code //unchanged
      break;

    case ICMP4_parameter_problem:
      *inner_ip4 = (ip4_header_t *)(((u8 *) icmp) + 8);
      *receiver_port = ip4_get_port(*inner_ip4, MAP_SENDER, icmp_len - 8);

      switch (icmp->code) {
        case ICMP4_parameter_problem_pointer_indicates_error:
        case ICMP4_parameter_problem_bad_length:
          icmp->type = ICMP6_parameter_problem;
          icmp->code = ICMP6_parameter_problem_erroneous_header_field;
          {
            u8 ptr = icmp_to_icmp6_updater_pointer_table[*((u8 *)(icmp + 1))];
            if (ptr == 0xff)
              return -1;

            *((u32 *)(icmp + 1)) = clib_host_to_net_u32(ptr);
          }
          break;
        default:
          //All other codes cause dropping the packet
          return -1;
      }
      break;

    default:
      //All other types cause dropping the packet
      return -1;
      break;
  }
  return 0;
}

static_always_inline void
_ip4_map_t_icmp (map_domain_t *d, vlib_buffer_t *p, u8 *error)
{
  ip4_header_t *ip4, *inner_ip4;
  ip6_header_t *ip6, *inner_ip6;
  u32 ip_len;
  icmp46_header_t *icmp;
  i32 recv_port;
  ip_csum_t csum;
  u16 *inner_L4_checksum = 0;
  ip6_frag_hdr_t *inner_frag;
  u32 inner_frag_id;
  u32 inner_frag_offset;
  u8 inner_frag_more;

  ip4 = vlib_buffer_get_current(p);
  ip_len = clib_net_to_host_u16(ip4->length);
  ASSERT(ip_len <= p->current_length);

  icmp = (icmp46_header_t *)(ip4 + 1);
  if (ip4_icmp_to_icmp6_in_place(icmp, ip_len - sizeof(*ip4),
                                &recv_port, &inner_ip4)) {
    *error = MAP_ERROR_ICMP;
    return;
  }

  if (recv_port < 0) {
    // In case of 1:1 mapping, we don't care about the port
    if(d->ea_bits_len == 0 && d->rules) {
      recv_port = 0;
    } else {
      *error = MAP_ERROR_ICMP;
      return;
    }
  }

  if (inner_ip4) {
    //We have 2 headers to translate.
    //We need to make some room in the middle of the packet

    if (PREDICT_FALSE(ip4_is_fragment(inner_ip4))) {
      //Here it starts getting really tricky
      //We will add a fragmentation header in the inner packet

      if (!ip4_is_first_fragment(inner_ip4)) {
        //For now we do not handle unless it is the first fragment
        //Ideally we should handle the case as we are in slow path already
        *error = MAP_ERROR_FRAGMENTED;
        return;
      }

      vlib_buffer_advance(p, - 2*(sizeof(*ip6) - sizeof(*ip4)) - sizeof(*inner_frag));
      ip6 = vlib_buffer_get_current(p);
      clib_memcpy(u8_ptr_add(ip6, sizeof(*ip6) - sizeof(*ip4)), ip4, 20 + 8);
      ip4 = (ip4_header_t *) u8_ptr_add(ip6, sizeof(*ip6) - sizeof(*ip4));
      icmp = (icmp46_header_t *) (ip4 + 1);

      inner_ip6 = (ip6_header_t *) u8_ptr_add(inner_ip4, sizeof(*ip4) - sizeof(*ip6) - sizeof(*inner_frag));
      inner_frag = (ip6_frag_hdr_t *) u8_ptr_add(inner_ip6, sizeof(*inner_ip6));
      ip6->payload_length = u16_net_add(ip4->length, sizeof(*ip6) - 2*sizeof(*ip4) + sizeof(*inner_frag));
      inner_frag_id = frag_id_4to6(inner_ip4->fragment_id);
      inner_frag_offset = ip4_get_fragment_offset(inner_ip4);
      inner_frag_more = !!(inner_ip4->flags_and_fragment_offset & clib_net_to_host_u16(IP4_HEADER_FLAG_MORE_FRAGMENTS));
    } else {
      vlib_buffer_advance(p, - 2*(sizeof(*ip6) - sizeof(*ip4)));
      ip6 = vlib_buffer_get_current(p);
      clib_memcpy(u8_ptr_add(ip6, sizeof(*ip6) - sizeof(*ip4)), ip4, 20 + 8);
      ip4 = (ip4_header_t *) u8_ptr_add(ip6, sizeof(*ip6) - sizeof(*ip4));
      icmp = (icmp46_header_t *) u8_ptr_add(ip4, sizeof(*ip4));
      inner_ip6 = (ip6_header_t *) u8_ptr_add(inner_ip4, sizeof(*ip4) - sizeof(*ip6));
      ip6->payload_length = u16_net_add(ip4->length, sizeof(*ip6) - 2*sizeof(*ip4));
      inner_frag = NULL;
    }

    if (PREDICT_TRUE(inner_ip4->protocol == IP_PROTOCOL_TCP)) {
      inner_L4_checksum = &((tcp_header_t *) (inner_ip4 + 1))->checksum;
      *inner_L4_checksum = ip_csum_fold(ip_csum_sub_even(*inner_L4_checksum, *((u64 *) (&inner_ip4->src_address))));
    } else if (PREDICT_TRUE(inner_ip4->protocol == IP_PROTOCOL_UDP)) {
      inner_L4_checksum = &((udp_header_t *) (inner_ip4 + 1))->checksum;
      if (!*inner_L4_checksum) {
        //The inner packet was first translated, and therefore came from IPv6.
        //As the packet was an IPv6 packet, the UDP checksum can't be NULL
        *error = MAP_ERROR_ICMP;
        return;
      }
      *inner_L4_checksum = ip_csum_fold(ip_csum_sub_even(*inner_L4_checksum, *((u64 *)(&inner_ip4->src_address))));
    } else if (inner_ip4->protocol == IP_PROTOCOL_ICMP) {
      //We have an ICMP inside an ICMP
      //It needs to be translated, but not for error ICMP messages
      icmp46_header_t *inner_icmp = (icmp46_header_t *) (inner_ip4 + 1);
      csum = inner_icmp->checksum;
      //Only types ICMP4_echo_request and ICMP4_echo_reply are handled by ip4_icmp_to_icmp6_in_place
      csum = ip_csum_sub_even(csum, *((u16 *)inner_icmp));
      inner_icmp->type = (inner_icmp->type == ICMP4_echo_request)?
          ICMP6_echo_request:ICMP6_echo_reply;
      csum = ip_csum_add_even(csum, *((u16 *)inner_icmp));
      csum = ip_csum_add_even(csum, clib_host_to_net_u16(IP_PROTOCOL_ICMP6));
      csum = ip_csum_add_even(csum, inner_ip4->length - sizeof(*inner_ip4));
      inner_icmp->checksum = ip_csum_fold(csum);
      inner_L4_checksum = &inner_icmp->checksum;
      inner_ip4->protocol = IP_PROTOCOL_ICMP6;
    } else {
      ASSERT(0); // We had a port from that, so it is udp or tcp or ICMP
    }

    //FIXME: Security check with the port found in the inner packet

    csum = *inner_L4_checksum; //Initial checksum of the inner L4 header
    //FIXME: Shouldn't we remove ip addresses from there ?

    inner_ip6->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32((6 << 28) + (inner_ip4->tos << 20));
    inner_ip6->payload_length = u16_net_add(inner_ip4->length, - sizeof(*inner_ip4));
    inner_ip6->hop_limit = inner_ip4->ttl;
    inner_ip6->protocol = inner_ip4->protocol;

    //Note that the source address is within the domain
    //while the destination address is the one outside the domain
    ip4_map_t_embedded_address(d, &inner_ip6->dst_address, &inner_ip4->dst_address);
    inner_ip6->src_address.as_u64[0] = map_get_pfx_net(d, inner_ip4->src_address.as_u32, recv_port);
    inner_ip6->src_address.as_u64[1] = map_get_sfx_net(d, inner_ip4->src_address.as_u32, recv_port);

    if (PREDICT_FALSE(inner_frag != NULL)) {
      inner_frag->next_hdr = inner_ip6->protocol;
      inner_frag->identification = inner_frag_id;
      inner_frag->rsv = 0;
      inner_frag->fragment_offset_and_more = ip6_frag_hdr_offset_and_more(inner_frag_offset, inner_frag_more);
      inner_ip6->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
      inner_ip6->payload_length = clib_host_to_net_u16(
          clib_net_to_host_u16(inner_ip6->payload_length) + sizeof(*inner_frag));
    }

    csum = ip_csum_add_even(csum, inner_ip6->src_address.as_u64[0]);
    csum = ip_csum_add_even(csum, inner_ip6->src_address.as_u64[1]);
    csum = ip_csum_add_even(csum, inner_ip6->dst_address.as_u64[0]);
    csum = ip_csum_add_even(csum, inner_ip6->dst_address.as_u64[1]);
    *inner_L4_checksum = ip_csum_fold(csum);

  } else {
    vlib_buffer_advance(p, sizeof(*ip4) - sizeof(*ip6));
    ip6 = vlib_buffer_get_current(p);
    ip6->payload_length = clib_host_to_net_u16(clib_net_to_host_u16(ip4->length) - sizeof(*ip4));
  }

  //Translate outer IPv6
  ip6->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32((6 << 28) + (ip4->tos << 20));

  ip6->hop_limit = ip4->ttl;
  ip6->protocol = IP_PROTOCOL_ICMP6;

  ip4_map_t_embedded_address(d, &ip6->src_address, &ip4->src_address);
  ip6->dst_address.as_u64[0] = map_get_pfx_net(d, ip4->dst_address.as_u32, recv_port);
  ip6->dst_address.as_u64[1] = map_get_sfx_net(d, ip4->dst_address.as_u32, recv_port);

  //Truncate when the packet exceeds the minimal IPv6 MTU
  if (p->current_length > 1280) {
    ip6->payload_length = clib_host_to_net_u16(1280 - sizeof(*ip6));
    p->current_length = 1280; //Looks too simple to be correct...
  }

  //TODO: We could do an easy diff-checksum for echo requests/replies
  //Recompute ICMP checksum
  icmp->checksum = 0;
  csum = ip_csum_with_carry(0, ip6->payload_length);
  csum = ip_csum_with_carry(csum, clib_host_to_net_u16(ip6->protocol));
  csum = ip_csum_with_carry(csum, ip6->src_address.as_u64[0]);
  csum = ip_csum_with_carry(csum, ip6->src_address.as_u64[1]);
  csum = ip_csum_with_carry(csum, ip6->dst_address.as_u64[0]);
  csum = ip_csum_with_carry(csum, ip6->dst_address.as_u64[1]);
  csum = ip_incremental_checksum(csum, icmp, clib_net_to_host_u16(ip6->payload_length));
  icmp->checksum = ~ip_csum_fold (csum);
}

static uword
ip4_map_t_icmp (vlib_main_t *vm,
                vlib_node_runtime_t *node,
                vlib_frame_t *frame)
{
  u32 n_left_from, *from, next_index, *to_next, n_left_to_next;
  vlib_node_runtime_t *error_node = vlib_node_get_runtime(vm, ip4_map_t_icmp_node.index);
  from = vlib_frame_vector_args(frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;
  vlib_combined_counter_main_t *cm = map_main.domain_counters;
  u32 cpu_index = os_get_cpu_number();

  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;
      ip4_mapt_icmp_next_t next0;
      u8 error0;
      map_domain_t *d0;
      u16 len0;

      next0 = IP4_MAPT_ICMP_NEXT_IP6_LOOKUP;
      pi0 = to_next[0] = from[0];
      from += 1;
      n_left_from -= 1;
      to_next +=1;
      n_left_to_next -= 1;
      error0 = MAP_ERROR_NONE;

      p0 = vlib_get_buffer(vm, pi0);
      vlib_buffer_advance(p0, sizeof(ip4_mapt_pseudo_header_t)); //The pseudo-header is not used
      len0 = clib_net_to_host_u16(((ip4_header_t *)vlib_buffer_get_current(p0))->length);
      d0 = pool_elt_at_index(map_main.domains, vnet_buffer(p0)->map_t.map_domain_index);
      _ip4_map_t_icmp(d0, p0, &error0);

      if(vnet_buffer(p0)->map_t.mtu < p0->current_length) {
        vnet_buffer(p0)->ip_frag.header_offset = 0;
        vnet_buffer(p0)->ip_frag.mtu = vnet_buffer(p0)->map_t.mtu;
        vnet_buffer(p0)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
        next0 = IP4_MAPT_ICMP_NEXT_IP6_FRAG;
      }
      if (PREDICT_TRUE(error0 == MAP_ERROR_NONE)) {
             vlib_increment_combined_counter(cm + MAP_DOMAIN_COUNTER_TX, cpu_index,
                                             vnet_buffer(p0)->map_t.map_domain_index, 1,
                                             len0);
      } else {
        next0 = IP4_MAPT_ICMP_NEXT_DROP;
      }
      p0->error = error_node->errors[error0];
      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;
}

static uword
ip4_map_t_fragmented (vlib_main_t *vm,
                      vlib_node_runtime_t *node,
                      vlib_frame_t *frame)
{
  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;
      ip4_header_t *ip40;
      ip6_header_t *ip60;
      ip6_frag_hdr_t *frag0;
      ip4_mapt_pseudo_header_t *pheader0;
      ip4_mapt_fragmented_next_t next0;

      next0 = IP4_MAPT_FRAGMENTED_NEXT_IP6_LOOKUP;
      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);

      //Accessing pseudo header
      pheader0 = vlib_buffer_get_current(p0);
      vlib_buffer_advance(p0, sizeof(*pheader0));

      //Accessing ip4 header
      ip40 = vlib_buffer_get_current(p0);
      frag0 = (ip6_frag_hdr_t *) u8_ptr_add(ip40, sizeof(*ip40) - sizeof(*frag0));
      ip60 = (ip6_header_t *) u8_ptr_add(ip40, sizeof(*ip40) - sizeof(*frag0) - sizeof(*ip60));
      vlib_buffer_advance(p0, sizeof(*ip40) - sizeof(*ip60) - sizeof(*frag0));

      //We know that the protocol was one of ICMP, TCP or UDP
      //because the first fragment was found and cached
      frag0->next_hdr = (ip40->protocol == IP_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP6 : ip40->protocol;
      frag0->identification = frag_id_4to6(ip40->fragment_id);
      frag0->rsv = 0;
      frag0->fragment_offset_and_more = ip6_frag_hdr_offset_and_more(
          ip4_get_fragment_offset(ip40),
          clib_net_to_host_u16(ip40->flags_and_fragment_offset) & IP4_HEADER_FLAG_MORE_FRAGMENTS);

      ip60->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32((6 << 28) + (ip40->tos << 20));
      ip60->payload_length = clib_host_to_net_u16(clib_net_to_host_u16(ip40->length) - sizeof(*ip40) + sizeof(*frag0));
      ip60->hop_limit = ip40->ttl;
      ip60->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
      ip60->dst_address.as_u64[0] = pheader0->daddr.as_u64[0];
      ip60->dst_address.as_u64[1] = pheader0->daddr.as_u64[1];
      ip60->src_address.as_u64[0] = pheader0->saddr.as_u64[0];
      ip60->src_address.as_u64[1] = pheader0->saddr.as_u64[1];

      if(vnet_buffer(p0)->map_t.mtu < p0->current_length) {
        vnet_buffer(p0)->ip_frag.header_offset = 0;
        vnet_buffer(p0)->ip_frag.mtu = vnet_buffer(p0)->map_t.mtu;
        vnet_buffer(p0)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
        next0 = IP4_MAPT_FRAGMENTED_NEXT_IP6_FRAG;
      }

      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;
}

static uword
ip4_map_t_tcp_udp(vlib_main_t *vm,
                  vlib_node_runtime_t *node,
                  vlib_frame_t *frame)
{
  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);

#ifdef IP4_MAP_T_DUAL_LOOP
    while (n_left_from >= 4 && n_left_to_next >= 2) {
      u32 pi0, pi1;
      vlib_buffer_t *p0, *p1;
      ip4_header_t *ip40, *ip41;
      ip6_header_t *ip60, *ip61;
      ip_csum_t csum0, csum1;
      u16 *checksum0, *checksum1;
      ip6_frag_hdr_t *frag0, *frag1;
      u32 frag_id0, frag_id1;
      ip4_mapt_pseudo_header_t *pheader0, *pheader1;
      ip4_mapt_tcp_udp_next_t next0, next1;

      pi0 = to_next[0] = from[0];
      pi1 = to_next[1] = from[1];
      from += 2;
      n_left_from -= 2;
      to_next +=2;
      n_left_to_next -= 2;

      next0 = IP4_MAPT_TCP_UDP_NEXT_IP6_LOOKUP;
      next1 = IP4_MAPT_TCP_UDP_NEXT_IP6_LOOKUP;
      p0 = vlib_get_buffer(vm, pi0);
      p1 = vlib_get_buffer(vm, pi1);

      //Accessing pseudo header
      pheader0 = vlib_buffer_get_current(p0);
      pheader1 = vlib_buffer_get_current(p1);
      vlib_buffer_advance(p0, sizeof(*pheader0));
      vlib_buffer_advance(p1, sizeof(*pheader1));

      //Accessing ip4 header
      ip40 = vlib_buffer_get_current(p0);
      ip41 = vlib_buffer_get_current(p1);
      checksum0 = (u16 *) u8_ptr_add(ip40, vnet_buffer(p0)->map_t.checksum_offset);
      checksum1 = (u16 *) u8_ptr_add(ip41, vnet_buffer(p1)->map_t.checksum_offset);

      //UDP checksum is optional over IPv4 but mandatory for IPv6
      //We do not check udp->length sanity but use our safe computed value instead
      if (PREDICT_FALSE(!*checksum0 && ip40->protocol == IP_PROTOCOL_UDP)) {
        u16 udp_len = clib_host_to_net_u16(ip40->length) - sizeof(*ip40);
        udp_header_t *udp = (udp_header_t *) u8_ptr_add(ip40, sizeof(*ip40));
        ip_csum_t csum;
        csum = ip_incremental_checksum(0, udp, udp_len);
        csum = ip_csum_with_carry(csum, clib_host_to_net_u16(udp_len));
        csum = ip_csum_with_carry(csum, clib_host_to_net_u16(IP_PROTOCOL_UDP));
        csum = ip_csum_with_carry(csum, *((u64 *)(&ip40->src_address)));
        *checksum0 = ~ip_csum_fold(csum);
      }
      if (PREDICT_FALSE(!*checksum1 && ip41->protocol == IP_PROTOCOL_UDP)) {
        u16 udp_len = clib_host_to_net_u16(ip41->length) - sizeof(*ip40);
        udp_header_t *udp = (udp_header_t *) u8_ptr_add(ip41, sizeof(*ip40));
        ip_csum_t csum;
        csum = ip_incremental_checksum(0, udp, udp_len);
        csum = ip_csum_with_carry(csum, clib_host_to_net_u16(udp_len));
        csum = ip_csum_with_carry(csum, clib_host_to_net_u16(IP_PROTOCOL_UDP));
        csum = ip_csum_with_carry(csum, *((u64 *)(&ip41->src_address)));
        *checksum1 = ~ip_csum_fold(csum);
      }

      csum0 = ip_csum_sub_even(*checksum0, ip40->src_address.as_u32);
      csum1 = ip_csum_sub_even(*checksum1, ip41->src_address.as_u32);
      csum0 = ip_csum_sub_even(csum0, ip40->dst_address.as_u32);
      csum1 = ip_csum_sub_even(csum1, ip41->dst_address.as_u32);

      // Deal with fragmented packets
      if (PREDICT_FALSE(ip40->flags_and_fragment_offset &
                       clib_host_to_net_u16(IP4_HEADER_FLAG_MORE_FRAGMENTS))) {
        ip60 = (ip6_header_t *) u8_ptr_add(ip40, sizeof(*ip40) - sizeof(*ip60) - sizeof(*frag0));
        frag0 = (ip6_frag_hdr_t *) u8_ptr_add(ip40, sizeof(*ip40) - sizeof(*frag0));
        frag_id0 = frag_id_4to6(ip40->fragment_id);
        vlib_buffer_advance(p0, sizeof(*ip40) - sizeof(*ip60) - sizeof(*frag0));
      } else {
        ip60 = (ip6_header_t *) (((u8 *)ip40) + sizeof(*ip40) - sizeof(*ip60));
        vlib_buffer_advance(p0, sizeof(*ip40) - sizeof(*ip60));
        frag0 = NULL;
      }

      if (PREDICT_FALSE(ip41->flags_and_fragment_offset &
                       clib_host_to_net_u16(IP4_HEADER_FLAG_MORE_FRAGMENTS))) {
        ip61 = (ip6_header_t *) u8_ptr_add(ip41, sizeof(*ip40) - sizeof(*ip60) - sizeof(*frag0));
        frag1 = (ip6_frag_hdr_t *) u8_ptr_add(ip41, sizeof(*ip40) - sizeof(*frag0));
        frag_id1 = frag_id_4to6(ip41->fragment_id);
        vlib_buffer_advance(p1, sizeof(*ip40) - sizeof(*ip60) - sizeof(*frag0));
      } else {
        ip61 = (ip6_header_t *) (((u8 *)ip41) + sizeof(*ip40) - sizeof(*ip60));
        vlib_buffer_advance(p1, sizeof(*ip40) - sizeof(*ip60));
        frag1 = NULL;
      }

      ip60->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32((6 << 28) + (ip40->tos << 20));
      ip61->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32((6 << 28) + (ip41->tos << 20));
      ip60->payload_length = u16_net_add(ip40->length, - sizeof(*ip40));
      ip61->payload_length = u16_net_add(ip41->length, - sizeof(*ip40));
      ip60->hop_limit = ip40->ttl;
      ip61->hop_limit = ip41->ttl;
      ip60->protocol = ip40->protocol;
      ip61->protocol = ip41->protocol;

      if (PREDICT_FALSE(frag0 != NULL)) {
        frag0->next_hdr = ip60->protocol;
        frag0->identification = frag_id0;
        frag0->rsv = 0;
        frag0->fragment_offset_and_more = ip6_frag_hdr_offset_and_more(0, 1);
        ip60->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
        ip60->payload_length = u16_net_add(ip60->payload_length, sizeof(*frag0));
      }

      if (PREDICT_FALSE(frag1 != NULL)) {
        frag1->next_hdr = ip61->protocol;
        frag1->identification = frag_id1;
        frag1->rsv = 0;
        frag1->fragment_offset_and_more = ip6_frag_hdr_offset_and_more(0, 1);
        ip61->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
        ip61->payload_length = u16_net_add(ip61->payload_length, sizeof(*frag0));
      }

      //Finally copying the address
      ip60->dst_address.as_u64[0] = pheader0->daddr.as_u64[0];
      ip61->dst_address.as_u64[0] = pheader1->daddr.as_u64[0];
      ip60->dst_address.as_u64[1] = pheader0->daddr.as_u64[1];
      ip61->dst_address.as_u64[1] = pheader1->daddr.as_u64[1];
      ip60->src_address.as_u64[0] = pheader0->saddr.as_u64[0];
      ip61->src_address.as_u64[0] = pheader1->saddr.as_u64[0];
      ip60->src_address.as_u64[1] = pheader0->saddr.as_u64[1];
      ip61->src_address.as_u64[1] = pheader1->saddr.as_u64[1];

      csum0 = ip_csum_add_even(csum0, ip60->src_address.as_u64[0]);
      csum1 = ip_csum_add_even(csum1, ip61->src_address.as_u64[0]);
      csum0 = ip_csum_add_even(csum0, ip60->src_address.as_u64[1]);
      csum1 = ip_csum_add_even(csum1, ip61->src_address.as_u64[1]);
      csum0 = ip_csum_add_even(csum0, ip60->dst_address.as_u64[0]);
      csum1 = ip_csum_add_even(csum1, ip61->dst_address.as_u64[0]);
      csum0 = ip_csum_add_even(csum0, ip60->dst_address.as_u64[1]);
      csum1 = ip_csum_add_even(csum1, ip61->dst_address.as_u64[1]);
      *checksum0 = ip_csum_fold(csum0);
      *checksum1 = ip_csum_fold(csum1);

      if(vnet_buffer(p0)->map_t.mtu < p0->current_length) {
        vnet_buffer(p0)->ip_frag.header_offset = 0;
        vnet_buffer(p0)->ip_frag.mtu = vnet_buffer(p0)->map_t.mtu;
        vnet_buffer(p0)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
        next0 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
      }

      if(vnet_buffer(p1)->map_t.mtu < p1->current_length) {
        vnet_buffer(p1)->ip_frag.header_offset = 0;
        vnet_buffer(p1)->ip_frag.mtu = vnet_buffer(p1)->map_t.mtu;
        vnet_buffer(p1)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
        next1 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
      }

      vlib_validate_buffer_enqueue_x2(vm, node, next_index,
                                      to_next, n_left_to_next, pi0, pi1,
                                      next0, next1);
    }
#endif

    while (n_left_from > 0 && n_left_to_next > 0) {
      u32 pi0;
      vlib_buffer_t *p0;
      ip4_header_t *ip40;
      ip6_header_t *ip60;
      ip_csum_t csum0;
      u16 *checksum0;
      ip6_frag_hdr_t *frag0;
      u32 frag_id0;
      ip4_mapt_pseudo_header_t *pheader0;
      ip4_mapt_tcp_udp_next_t next0;

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

      next0 = IP4_MAPT_TCP_UDP_NEXT_IP6_LOOKUP;
      p0 = vlib_get_buffer(vm, pi0);

      //Accessing pseudo header
      pheader0 = vlib_buffer_get_current(p0);
      vlib_buffer_advance(p0, sizeof(*pheader0));

      //Accessing ip4 header
      ip40 = vlib_buffer_get_current(p0);
      checksum0 = (u16 *) u8_ptr_add(ip40, vnet_buffer(p0)->map_t.checksum_offset);

      //UDP checksum is optional over IPv4 but mandatory for IPv6
      //We do not check udp->length sanity but use our safe computed value instead
      if (PREDICT_FALSE(!*checksum0 && ip40->protocol == IP_PROTOCOL_UDP)) {
        u16 udp_len = clib_host_to_net_u16(ip40->length) - sizeof(*ip40);
        udp_header_t *udp = (udp_header_t *) u8_ptr_add(ip40, sizeof(*ip40));
        ip_csum_t csum;
        csum = ip_incremental_checksum(0, udp, udp_len);
        csum = ip_csum_with_carry(csum, clib_host_to_net_u16(udp_len));
        csum = ip_csum_with_carry(csum, clib_host_to_net_u16(IP_PROTOCOL_UDP));
        csum = ip_csum_with_carry(csum, *((u64 *)(&ip40->src_address)));
        *checksum0 = ~ip_csum_fold(csum);
      }

      csum0 = ip_csum_sub_even(*checksum0, ip40->src_address.as_u32);
      csum0 = ip_csum_sub_even(csum0, ip40->dst_address.as_u32);

      // Deal with fragmented packets
      if (PREDICT_FALSE(ip40->flags_and_fragment_offset &
                       clib_host_to_net_u16(IP4_HEADER_FLAG_MORE_FRAGMENTS))) {
        ip60 = (ip6_header_t *) u8_ptr_add(ip40, sizeof(*ip40) - sizeof(*ip60) - sizeof(*frag0));
        frag0 = (ip6_frag_hdr_t *) u8_ptr_add(ip40, sizeof(*ip40) - sizeof(*frag0));
        frag_id0 = frag_id_4to6(ip40->fragment_id);
        vlib_buffer_advance(p0, sizeof(*ip40) - sizeof(*ip60) - sizeof(*frag0));
      } else {
        ip60 = (ip6_header_t *) (((u8 *)ip40) + sizeof(*ip40) - sizeof(*ip60));
        vlib_buffer_advance(p0, sizeof(*ip40) - sizeof(*ip60));
        frag0 = NULL;
      }

      ip60->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32((6 << 28) + (ip40->tos << 20));
      ip60->payload_length = u16_net_add(ip40->length, - sizeof(*ip40));
      ip60->hop_limit = ip40->ttl;
      ip60->protocol = ip40->protocol;

      if (PREDICT_FALSE(frag0 != NULL)) {
        frag0->next_hdr = ip60->protocol;
        frag0->identification = frag_id0;
        frag0->rsv = 0;
        frag0->fragment_offset_and_more = ip6_frag_hdr_offset_and_more(0, 1);
        ip60->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION;
        ip60->payload_length = u16_net_add(ip60->payload_length, sizeof(*frag0));
      }

      //Finally copying the address
      ip60->dst_address.as_u64[0] = pheader0->daddr.as_u64[0];
      ip60->dst_address.as_u64[1] = pheader0->daddr.as_u64[1];
      ip60->src_address.as_u64[0] = pheader0->saddr.as_u64[0];
      ip60->src_address.as_u64[1] = pheader0->saddr.as_u64[1];

      csum0 = ip_csum_add_even(csum0, ip60->src_address.as_u64[0]);
      csum0 = ip_csum_add_even(csum0, ip60->src_address.as_u64[1]);
      csum0 = ip_csum_add_even(csum0, ip60->dst_address.as_u64[0]);
      csum0 = ip_csum_add_even(csum0, ip60->dst_address.as_u64[1]);
      *checksum0 = ip_csum_fold(csum0);

      if(vnet_buffer(p0)->map_t.mtu < p0->current_length) {
        //Send to fragmentation node if necessary
        vnet_buffer(p0)->ip_frag.header_offset = 0;
        vnet_buffer(p0)->ip_frag.mtu = vnet_buffer(p0)->map_t.mtu;
        vnet_buffer(p0)->ip_frag.next_index = IP6_FRAG_NEXT_IP6_LOOKUP;
        next0 = IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG;
      }

      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;
}

static_always_inline void
ip4_map_t_classify(vlib_buffer_t *p0, map_domain_t *d0, ip4_header_t *ip40, u16 ip4_len0,
                   i32 *dst_port0, u8 *error0, ip4_mapt_next_t *next0)
{
  if (PREDICT_FALSE(ip4_get_fragment_offset(ip40))) {
    *next0 = IP4_MAPT_NEXT_MAPT_FRAGMENTED;
    if(d0->ea_bits_len == 0 && d0->rules) {
      *dst_port0 = 0;
    } else {
      *dst_port0 = ip4_map_fragment_get_port(ip40);
      *error0 = (*dst_port0 == -1) ? MAP_ERROR_FRAGMENT_MEMORY : *error0;
    }
  } else if (PREDICT_TRUE(ip40->protocol == IP_PROTOCOL_TCP)) {
    vnet_buffer(p0)->map_t.checksum_offset = 36;
    *next0 = IP4_MAPT_NEXT_MAPT_TCP_UDP;
    *error0 = ip4_len0 < 40 ? MAP_ERROR_MALFORMED : *error0;
    *dst_port0 = (i32) *((u16 *)u8_ptr_add(ip40, sizeof(*ip40) + 2));
  } else if (PREDICT_TRUE(ip40->protocol == IP_PROTOCOL_UDP)) {
    vnet_buffer(p0)->map_t.checksum_offset = 26;
    *next0 = IP4_MAPT_NEXT_MAPT_TCP_UDP;
    *error0 = ip4_len0 < 28 ? MAP_ERROR_MALFORMED : *error0;
    *dst_port0 = (i32) *((u16 *)u8_ptr_add(ip40, sizeof(*ip40) + 2));
  } else if (ip40->protocol == IP_PROTOCOL_ICMP) {
    *next0 = IP4_MAPT_NEXT_MAPT_ICMP;
    if(d0->ea_bits_len == 0 && d0->rules)
      *dst_port0 = 0;
    else if (((icmp46_header_t *) u8_ptr_add(ip40, sizeof(*ip40)))->code == ICMP4_echo_reply ||
        ((icmp46_header_t *) u8_ptr_add(ip40, sizeof(*ip40)))->code == ICMP4_echo_request)
      *dst_port0 = (i32) *((u16 *)u8_ptr_add(ip40, sizeof(*ip40) + 6));
  } else {
    *error0 = MAP_ERROR_BAD_PROTOCOL;
  }
}

static uword
ip4_map_t (vlib_main_t *vm,
           vlib_node_runtime_t *node,
           vlib_frame_t *frame)
{
  u32 n_left_from, *from, next_index, *to_next, n_left_to_next;
  vlib_node_runtime_t *error_node = vlib_node_get_runtime(vm, ip4_map_t_node.index);
  from = vlib_frame_vector_args(frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;
  vlib_combined_counter_main_t *cm = map_main.domain_counters;
  u32 cpu_index = os_get_cpu_number();

  while (n_left_from > 0) {
    vlib_get_next_frame(vm, node, next_index, to_next, n_left_to_next);

#ifdef IP4_MAP_T_DUAL_LOOP
    while (n_left_from >= 4 && n_left_to_next >= 2) {
      u32 pi0, pi1;
      vlib_buffer_t *p0, *p1;
      ip4_header_t *ip40, *ip41;
      map_domain_t *d0, *d1;
      ip4_mapt_next_t next0 = 0, next1 = 0;
      u16 ip4_len0, ip4_len1;
      u8 error0, error1;
      i32 dst_port0, dst_port1;
      ip4_mapt_pseudo_header_t *pheader0, *pheader1;

      pi0 = to_next[0] = from[0];
      pi1 = to_next[1] = from[1];
      from += 2;
      n_left_from -= 2;
      to_next +=2;
      n_left_to_next -= 2;
      error0 = MAP_ERROR_NONE;
      error1 = MAP_ERROR_NONE;

      p0 = vlib_get_buffer(vm, pi0);
      p1 = vlib_get_buffer(vm, pi1);
      ip40 = vlib_buffer_get_current(p0);
      ip41 = vlib_buffer_get_current(p1);
      ip4_len0 = clib_host_to_net_u16(ip40->length);
      ip4_len1 = clib_host_to_net_u16(ip41->length);

      if (PREDICT_FALSE(p0->current_length < ip4_len0 ||
                        ip40->ip_version_and_header_length != 0x45)) {
        error0 = MAP_ERROR_UNKNOWN;
        next0 = IP4_MAPT_NEXT_DROP;
      }

      if (PREDICT_FALSE(p1->current_length < ip4_len1 ||
                        ip41->ip_version_and_header_length != 0x45)) {
        error1 = MAP_ERROR_UNKNOWN;
        next1 = IP4_MAPT_NEXT_DROP;
      }

      d0 = ip4_map_get_domain(vnet_buffer(p0)->ip.adj_index[VLIB_TX],
                              &vnet_buffer(p0)->map_t.map_domain_index);
      d1 = ip4_map_get_domain(vnet_buffer(p1)->ip.adj_index[VLIB_TX],
                                    &vnet_buffer(p1)->map_t.map_domain_index);

      vnet_buffer(p0)->map_t.mtu = d0->mtu ? d0->mtu : ~0;
      vnet_buffer(p1)->map_t.mtu = d1->mtu ? d1->mtu : ~0;

      dst_port0 = -1;
      dst_port1 = -1;

      ip4_map_t_classify(p0, d0, ip40, ip4_len0, &dst_port0, &error0, &next0);
      ip4_map_t_classify(p1, d1, ip41, ip4_len1, &dst_port1, &error1, &next1);

      //Add MAP-T pseudo header in front of the packet
      vlib_buffer_advance(p0, - sizeof(*pheader0));
      vlib_buffer_advance(p1, - sizeof(*pheader1));
      pheader0 = vlib_buffer_get_current(p0);
      pheader1 = vlib_buffer_get_current(p1);

      //Save addresses within the packet
      ip4_map_t_embedded_address(d0, &pheader0->saddr, &ip40->src_address);
      ip4_map_t_embedded_address(d1, &pheader1->saddr, &ip41->src_address);
      pheader0->daddr.as_u64[0] = map_get_pfx_net(d0, ip40->dst_address.as_u32, (u16)dst_port0);
      pheader0->daddr.as_u64[1] = map_get_sfx_net(d0, ip40->dst_address.as_u32, (u16)dst_port0);
      pheader1->daddr.as_u64[0] = map_get_pfx_net(d1, ip41->dst_address.as_u32, (u16)dst_port1);
      pheader1->daddr.as_u64[1] = map_get_sfx_net(d1, ip41->dst_address.as_u32, (u16)dst_port1);

      if (PREDICT_FALSE(ip4_is_first_fragment(ip40) && (dst_port0 != -1) &&
                        (d0->ea_bits_len != 0 || !d0->rules) &&
                        ip4_map_fragment_cache(ip40, dst_port0))) {
        error0 = MAP_ERROR_FRAGMENT_MEMORY;
      }

      if (PREDICT_FALSE(ip4_is_first_fragment(ip41) && (dst_port1 != -1) &&
                        (d1->ea_bits_len != 0 || !d1->rules) &&
                        ip4_map_fragment_cache(ip41, dst_port1))) {
        error1 = MAP_ERROR_FRAGMENT_MEMORY;
      }

      if (PREDICT_TRUE(error0 == MAP_ERROR_NONE && next0 != IP4_MAPT_NEXT_MAPT_ICMP)) {
        vlib_increment_combined_counter(cm + MAP_DOMAIN_COUNTER_TX, cpu_index,
                                        vnet_buffer(p0)->map_t.map_domain_index, 1,
                                        clib_net_to_host_u16(ip40->length));
      }

      if (PREDICT_TRUE(error1 == MAP_ERROR_NONE && next1 != IP4_MAPT_NEXT_MAPT_ICMP)) {
        vlib_increment_combined_counter(cm + MAP_DOMAIN_COUNTER_TX, cpu_index,
                                        vnet_buffer(p1)->map_t.map_domain_index, 1,
                                        clib_net_to_host_u16(ip41->length));
      }

      next0 = (error0 != MAP_ERROR_NONE) ? IP4_MAPT_NEXT_DROP : next0;
      next1 = (error1 != MAP_ERROR_NONE) ? IP4_MAPT_NEXT_DROP : next1;
      p0->error = error_node->errors[error0];
      p1->error = error_node->errors[error1];
      vlib_validate_buffer_enqueue_x2(vm, node, next_index, to_next,
                                      n_left_to_next, pi0, pi1, next0, next1);
    }
#endif

    while (n_left_from > 0 && n_left_to_next > 0) {
      u32 pi0;
      vlib_buffer_t *p0;
      ip4_header_t *ip40;
      map_domain_t *d0;
      ip4_mapt_next_t next0;
      u16 ip4_len0;
      u8 error0;
      i32 dst_port0;
      ip4_mapt_pseudo_header_t *pheader0;

      pi0 = to_next[0] = from[0];
      from += 1;
      n_left_from -= 1;
      to_next +=1;
      n_left_to_next -= 1;
      error0 = MAP_ERROR_NONE;

      p0 = vlib_get_buffer(vm, pi0);
      ip40 = vlib_buffer_get_current(p0);
      ip4_len0 = clib_host_to_net_u16(ip40->length);
      if (PREDICT_FALSE(p0->current_length < ip4_len0 ||
                       ip40->ip_version_and_header_length != 0x45)) {
        error0 = MAP_ERROR_UNKNOWN;
        next0 = IP4_MAPT_NEXT_DROP;
      }

      d0 = ip4_map_get_domain(vnet_buffer(p0)->ip.adj_index[VLIB_TX],
                              &vnet_buffer(p0)->map_t.map_domain_index);

      vnet_buffer(p0)->map_t.mtu = d0->mtu ? d0->mtu : ~0;

      dst_port0 = -1;
      ip4_map_t_classify(p0, d0, ip40, ip4_len0, &dst_port0, &error0, &next0);

      //Add MAP-T pseudo header in front of the packet
      vlib_buffer_advance(p0, - sizeof(*pheader0));
      pheader0 = vlib_buffer_get_current(p0);

      //Save addresses within the packet
      ip4_map_t_embedded_address(d0, &pheader0->saddr, &ip40->src_address);
      pheader0->daddr.as_u64[0] = map_get_pfx_net(d0, ip40->dst_address.as_u32, (u16)dst_port0);
      pheader0->daddr.as_u64[1] = map_get_sfx_net(d0, ip40->dst_address.as_u32, (u16)dst_port0);

      //It is important to cache at this stage because the result might be necessary
      //for packets within the same vector.
      //Actually, this approach even provides some limited out-of-order fragments support
      if (PREDICT_FALSE(ip4_is_first_fragment(ip40) && (dst_port0 != -1) &&
                        (d0->ea_bits_len != 0 || !d0->rules) &&
                        ip4_map_fragment_cache(ip40, dst_port0))) {
          error0 = MAP_ERROR_UNKNOWN;
      }

      if (PREDICT_TRUE(error0 == MAP_ERROR_NONE && next0 != IP4_MAPT_NEXT_MAPT_ICMP)) {
        vlib_increment_combined_counter(cm + MAP_DOMAIN_COUNTER_TX, cpu_index,
                                        vnet_buffer(p0)->map_t.map_domain_index, 1,
                                        clib_net_to_host_u16(ip40->length));
      }

      next0 = (error0 != MAP_ERROR_NONE) ? IP4_MAPT_NEXT_DROP : next0;
      p0->error = error_node->errors[error0];
      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;
}

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

VLIB_REGISTER_NODE(ip4_map_t_fragmented_node) = {
  .function = ip4_map_t_fragmented,
  .name = "ip4-map-t-fragmented",
  .vector_size = sizeof(u32),
  .format_trace = format_map_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = MAP_N_ERROR,
  .error_strings = map_t_error_strings,

  .n_next_nodes = IP4_MAPT_FRAGMENTED_N_NEXT,
  .next_nodes = {
      [IP4_MAPT_FRAGMENTED_NEXT_IP6_LOOKUP] = "ip6-lookup",
      [IP4_MAPT_FRAGMENTED_NEXT_IP6_FRAG] = IP6_FRAG_NODE_NAME,
      [IP4_MAPT_FRAGMENTED_NEXT_DROP] = "error-drop",
  },
};

VLIB_REGISTER_NODE(ip4_map_t_icmp_node) = {
  .function = ip4_map_t_icmp,
  .name = "ip4-map-t-icmp",
  .vector_size = sizeof(u32),
  .format_trace = format_map_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = MAP_N_ERROR,
  .error_strings = map_t_error_strings,

  .n_next_nodes = IP4_MAPT_ICMP_N_NEXT,
  .next_nodes = {
      [IP4_MAPT_ICMP_NEXT_IP6_LOOKUP] = "ip6-lookup",
      [IP4_MAPT_ICMP_NEXT_IP6_FRAG] = IP6_FRAG_NODE_NAME,
      [IP4_MAPT_ICMP_NEXT_DROP] = "error-drop",
  },
};

VLIB_REGISTER_NODE(ip4_map_t_tcp_udp_node) = {
  .function = ip4_map_t_tcp_udp,
  .name = "ip4-map-t-tcp-udp",
  .vector_size = sizeof(u32),
  .format_trace = format_map_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = MAP_N_ERROR,
  .error_strings = map_t_error_strings,

  .n_next_nodes = IP4_MAPT_TCP_UDP_N_NEXT,
  .next_nodes = {
      [IP4_MAPT_TCP_UDP_NEXT_IP6_LOOKUP] = "ip6-lookup",
      [IP4_MAPT_TCP_UDP_NEXT_IP6_FRAG] = IP6_FRAG_NODE_NAME,
      [IP4_MAPT_TCP_UDP_NEXT_DROP] = "error-drop",
  },
};

VLIB_REGISTER_NODE(ip4_map_t_node) = {
  .function = ip4_map_t,
  .name = "ip4-map-t",
  .vector_size = sizeof(u32),
  .format_trace = format_map_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = MAP_N_ERROR,
  .error_strings = map_t_error_strings,

  .n_next_nodes = IP4_MAPT_N_NEXT,
  .next_nodes = {
      [IP4_MAPT_NEXT_MAPT_TCP_UDP] = "ip4-map-t-tcp-udp",
      [IP4_MAPT_NEXT_MAPT_ICMP] = "ip4-map-t-icmp",
      [IP4_MAPT_NEXT_MAPT_FRAGMENTED] = "ip4-map-t-fragmented",
      [IP4_MAPT_NEXT_DROP] = "error-drop",
  },
};