ip6_map.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 <vnet/ip/ip_frag.h>
#include <vnet/ip/ip4_to_ip6.h>
#include <vnet/ip/ip6_to_ip4.h>

enum ip6_map_next_e
{
  IP6_MAP_NEXT_IP4_LOOKUP,
#ifdef MAP_SKIP_IP6_LOOKUP
  IP6_MAP_NEXT_IP4_REWRITE,
#endif
  IP6_MAP_NEXT_IP6_REASS,
  IP6_MAP_NEXT_IP4_REASS,
  IP6_MAP_NEXT_IP4_FRAGMENT,
  IP6_MAP_NEXT_IP6_ICMP_RELAY,
  IP6_MAP_NEXT_IP6_LOCAL,
  IP6_MAP_NEXT_DROP,
  IP6_MAP_NEXT_ICMP,
  IP6_MAP_N_NEXT,
};

enum ip6_map_ip6_reass_next_e
{
  IP6_MAP_IP6_REASS_NEXT_IP6_MAP,
  IP6_MAP_IP6_REASS_NEXT_DROP,
  IP6_MAP_IP6_REASS_N_NEXT,
};

enum ip6_map_ip4_reass_next_e
{
  IP6_MAP_IP4_REASS_NEXT_IP4_LOOKUP,
  IP6_MAP_IP4_REASS_NEXT_IP4_FRAGMENT,
  IP6_MAP_IP4_REASS_NEXT_DROP,
  IP6_MAP_IP4_REASS_N_NEXT,
};

enum ip6_icmp_relay_next_e
{
  IP6_ICMP_RELAY_NEXT_IP4_LOOKUP,
  IP6_ICMP_RELAY_NEXT_DROP,
  IP6_ICMP_RELAY_N_NEXT,
};

vlib_node_registration_t ip6_map_ip4_reass_node;
vlib_node_registration_t ip6_map_ip6_reass_node;
static vlib_node_registration_t ip6_map_icmp_relay_node;

typedef struct
{
  u32 map_domain_index;
  u16 port;
  u8 cached;
} map_ip6_map_ip4_reass_trace_t;

u8 *
format_ip6_map_ip4_reass_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 *);
  map_ip6_map_ip4_reass_trace_t *t =
    va_arg (*args, map_ip6_map_ip4_reass_trace_t *);
  return format (s, "MAP domain index: %d L4 port: %u Status: %s",
                 t->map_domain_index, t->port,
                 t->cached ? "cached" : "forwarded");
}

typedef struct
{
  u16 offset;
  u16 frag_len;
  u8 out;
} map_ip6_map_ip6_reass_trace_t;

u8 *
format_ip6_map_ip6_reass_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 *);
  map_ip6_map_ip6_reass_trace_t *t =
    va_arg (*args, map_ip6_map_ip6_reass_trace_t *);
  return format (s, "Offset: %d Fragment length: %d Status: %s", t->offset,
                 t->frag_len, t->out ? "out" : "in");
}

/*
 * ip6_map_sec_check
 */
static_always_inline bool
ip6_map_sec_check (map_domain_t * d, u16 port, ip4_header_t * ip4,
                   ip6_header_t * ip6)
{
  u16 sp4 = clib_net_to_host_u16 (port);
  u32 sa4 = clib_net_to_host_u32 (ip4->src_address.as_u32);
  u64 sal6 = map_get_pfx (d, sa4, sp4);
  u64 sar6 = map_get_sfx (d, sa4, sp4);

  if (PREDICT_FALSE
      (sal6 != clib_net_to_host_u64 (ip6->src_address.as_u64[0])
       || sar6 != clib_net_to_host_u64 (ip6->src_address.as_u64[1])))
    return (false);
  return (true);
}

static_always_inline void
ip6_map_security_check (map_domain_t * d, ip4_header_t * ip4,
                        ip6_header_t * ip6, u32 * next, u8 * error)
{
  map_main_t *mm = &map_main;
  if (d->ea_bits_len || d->rules)
    {
      if (d->psid_length > 0)
        {
          if (!ip4_is_fragment (ip4))
            {
              u16 port = ip4_get_port (ip4, 1);
              if (port)
                {
                  if (mm->sec_check)
                    *error =
                      ip6_map_sec_check (d, port, ip4,
                                         ip6) ? MAP_ERROR_NONE :
                      MAP_ERROR_DECAP_SEC_CHECK;
                }
              else
                {
                  *error = MAP_ERROR_BAD_PROTOCOL;
                }
            }
          else
            {
              *next = mm->sec_check_frag ? IP6_MAP_NEXT_IP4_REASS : *next;
            }
        }
    }
}

static_always_inline bool
ip6_map_ip4_lookup_bypass (vlib_buffer_t * p0, ip4_header_t * ip)
{
#ifdef MAP_SKIP_IP6_LOOKUP
  if (FIB_NODE_INDEX_INVALID != pre_resolved[FIB_PROTOCOL_IP4].fei)
    {
      vnet_buffer (p0)->ip.adj_index[VLIB_TX] =
        pre_resolved[FIB_PROTOCOL_IP4].dpo.dpoi_index;
      return (true);
    }
#endif
  return (false);
}

/*
 * ip6_map
 */
static uword
ip6_map (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, ip6_map_node.index);
  map_main_t *mm = &map_main;
  vlib_combined_counter_main_t *cm = mm->domain_counters;
  u32 thread_index = vm->thread_index;

  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);

      /* Dual loop */
      while (n_left_from >= 4 && n_left_to_next >= 2)
        {
          u32 pi0, pi1;
          vlib_buffer_t *p0, *p1;
          u8 error0 = MAP_ERROR_NONE;
          u8 error1 = MAP_ERROR_NONE;
          map_domain_t *d0 = 0, *d1 = 0;
          ip4_header_t *ip40, *ip41;
          ip6_header_t *ip60, *ip61;
          u16 port0 = 0, port1 = 0;
          u32 map_domain_index0 = ~0, map_domain_index1 = ~0;
          u32 next0 = IP6_MAP_NEXT_IP4_LOOKUP;
          u32 next1 = IP6_MAP_NEXT_IP4_LOOKUP;

          /* Prefetch next iteration. */
          {
            vlib_buffer_t *p2, *p3;

            p2 = vlib_get_buffer (vm, from[2]);
            p3 = vlib_get_buffer (vm, from[3]);

            vlib_prefetch_buffer_header (p2, LOAD);
            vlib_prefetch_buffer_header (p3, LOAD);

            /* IPv6 + IPv4 header + 8 bytes of ULP */
            CLIB_PREFETCH (p2->data, 68, LOAD);
            CLIB_PREFETCH (p3->data, 68, LOAD);
          }

          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;

          p0 = vlib_get_buffer (vm, pi0);
          p1 = vlib_get_buffer (vm, pi1);
          ip60 = vlib_buffer_get_current (p0);
          ip61 = vlib_buffer_get_current (p1);
          vlib_buffer_advance (p0, sizeof (ip6_header_t));
          vlib_buffer_advance (p1, sizeof (ip6_header_t));
          ip40 = vlib_buffer_get_current (p0);
          ip41 = vlib_buffer_get_current (p1);

          /*
           * Encapsulated IPv4 packet
           *   - IPv4 fragmented -> Pass to virtual reassembly unless security check disabled
           *   - Lookup/Rewrite or Fragment node in case of packet > MTU
           * Fragmented IPv6 packet
           * ICMP IPv6 packet
           *   - Error -> Pass to ICMPv6/ICMPv4 relay
           *   - Info -> Pass to IPv6 local
           * Anything else -> drop
           */
          if (PREDICT_TRUE
              (ip60->protocol == IP_PROTOCOL_IP_IN_IP
               && clib_net_to_host_u16 (ip60->payload_length) > 20))
            {
              d0 =
                ip6_map_get_domain (vnet_buffer (p0)->ip.adj_index[VLIB_TX],
                                    (ip4_address_t *) & ip40->
                                    src_address.as_u32, &map_domain_index0,
                                    &error0);
            }
          else if (ip60->protocol == IP_PROTOCOL_ICMP6 &&
                   clib_net_to_host_u16 (ip60->payload_length) >
                   sizeof (icmp46_header_t))
            {
              icmp46_header_t *icmp = (void *) (ip60 + 1);
              next0 = (icmp->type == ICMP6_echo_request
                       || icmp->type ==
                       ICMP6_echo_reply) ? IP6_MAP_NEXT_IP6_LOCAL :
                IP6_MAP_NEXT_IP6_ICMP_RELAY;
            }
          else if (ip60->protocol == IP_PROTOCOL_IPV6_FRAGMENTATION)
            {
              next0 = IP6_MAP_NEXT_IP6_REASS;
            }
          else
            {
              error0 = MAP_ERROR_BAD_PROTOCOL;
            }
          if (PREDICT_TRUE
              (ip61->protocol == IP_PROTOCOL_IP_IN_IP
               && clib_net_to_host_u16 (ip61->payload_length) > 20))
            {
              d1 =
                ip6_map_get_domain (vnet_buffer (p1)->ip.adj_index[VLIB_TX],
                                    (ip4_address_t *) & ip41->
                                    src_address.as_u32, &map_domain_index1,
                                    &error1);
            }
          else if (ip61->protocol == IP_PROTOCOL_ICMP6 &&
                   clib_net_to_host_u16 (ip61->payload_length) >
                   sizeof (icmp46_header_t))
            {
              icmp46_header_t *icmp = (void *) (ip61 + 1);
              next1 = (icmp->type == ICMP6_echo_request
                       || icmp->type ==
                       ICMP6_echo_reply) ? IP6_MAP_NEXT_IP6_LOCAL :
                IP6_MAP_NEXT_IP6_ICMP_RELAY;
            }
          else if (ip61->protocol == IP_PROTOCOL_IPV6_FRAGMENTATION)
            {
              next1 = IP6_MAP_NEXT_IP6_REASS;
            }
          else
            {
              error1 = MAP_ERROR_BAD_PROTOCOL;
            }

          if (d0)
            {
              /* MAP inbound security check */
              ip6_map_security_check (d0, ip40, ip60, &next0, &error0);

              if (PREDICT_TRUE (error0 == MAP_ERROR_NONE &&
                                next0 == IP6_MAP_NEXT_IP4_LOOKUP))
                {
                  if (PREDICT_FALSE
                      (d0->mtu
                       && (clib_host_to_net_u16 (ip40->length) > d0->mtu)))
                    {
                      vnet_buffer (p0)->ip_frag.flags = 0;
                      vnet_buffer (p0)->ip_frag.next_index =
                        IP4_FRAG_NEXT_IP4_LOOKUP;
                      vnet_buffer (p0)->ip_frag.mtu = d0->mtu;
                      next0 = IP6_MAP_NEXT_IP4_FRAGMENT;
                    }
                  else
                    {
                      next0 =
                        ip6_map_ip4_lookup_bypass (p0,
                                                   ip40) ?
                        IP6_MAP_NEXT_IP4_REWRITE : next0;
                    }
                  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_RX,
                                                   thread_index,
                                                   map_domain_index0, 1,
                                                   clib_net_to_host_u16
                                                   (ip40->length));
                }
            }
          if (d1)
            {
              /* MAP inbound security check */
              ip6_map_security_check (d1, ip41, ip61, &next1, &error1);

              if (PREDICT_TRUE (error1 == MAP_ERROR_NONE &&
                                next1 == IP6_MAP_NEXT_IP4_LOOKUP))
                {
                  if (PREDICT_FALSE
                      (d1->mtu
                       && (clib_host_to_net_u16 (ip41->length) > d1->mtu)))
                    {
                      vnet_buffer (p1)->ip_frag.flags = 0;
                      vnet_buffer (p1)->ip_frag.next_index =
                        IP4_FRAG_NEXT_IP4_LOOKUP;
                      vnet_buffer (p1)->ip_frag.mtu = d1->mtu;
                      next1 = IP6_MAP_NEXT_IP4_FRAGMENT;
                    }
                  else
                    {
                      next1 =
                        ip6_map_ip4_lookup_bypass (p1,
                                                   ip41) ?
                        IP6_MAP_NEXT_IP4_REWRITE : next1;
                    }
                  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_RX,
                                                   thread_index,
                                                   map_domain_index1, 1,
                                                   clib_net_to_host_u16
                                                   (ip41->length));
                }
            }

          if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
            {
              map_trace_t *tr = vlib_add_trace (vm, node, p0, sizeof (*tr));
              tr->map_domain_index = map_domain_index0;
              tr->port = port0;
            }

          if (PREDICT_FALSE (p1->flags & VLIB_BUFFER_IS_TRACED))
            {
              map_trace_t *tr = vlib_add_trace (vm, node, p1, sizeof (*tr));
              tr->map_domain_index = map_domain_index1;
              tr->port = port1;
            }

          if (error0 == MAP_ERROR_DECAP_SEC_CHECK && mm->icmp6_enabled)
            {
              /* Set ICMP parameters */
              vlib_buffer_advance (p0, -sizeof (ip6_header_t));
              icmp6_error_set_vnet_buffer (p0, ICMP6_destination_unreachable,
                                           ICMP6_destination_unreachable_source_address_failed_policy,
                                           0);
              next0 = IP6_MAP_NEXT_ICMP;
            }
          else
            {
              next0 = (error0 == MAP_ERROR_NONE) ? next0 : IP6_MAP_NEXT_DROP;
            }

          if (error1 == MAP_ERROR_DECAP_SEC_CHECK && mm->icmp6_enabled)
            {
              /* Set ICMP parameters */
              vlib_buffer_advance (p1, -sizeof (ip6_header_t));
              icmp6_error_set_vnet_buffer (p1, ICMP6_destination_unreachable,
                                           ICMP6_destination_unreachable_source_address_failed_policy,
                                           0);
              next1 = IP6_MAP_NEXT_ICMP;
            }
          else
            {
              next1 = (error1 == MAP_ERROR_NONE) ? next1 : IP6_MAP_NEXT_DROP;
            }

          /* Reset packet */
          if (next0 == IP6_MAP_NEXT_IP6_LOCAL)
            vlib_buffer_advance (p0, -sizeof (ip6_header_t));
          if (next1 == IP6_MAP_NEXT_IP6_LOCAL)
            vlib_buffer_advance (p1, -sizeof (ip6_header_t));

          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);
        }

      /* Single loop */
      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 pi0;
          vlib_buffer_t *p0;
          u8 error0 = MAP_ERROR_NONE;
          map_domain_t *d0 = 0;
          ip4_header_t *ip40;
          ip6_header_t *ip60;
          i32 port0 = 0;
          u32 map_domain_index0 = ~0;
          u32 next0 = IP6_MAP_NEXT_IP4_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);
          ip60 = vlib_buffer_get_current (p0);
          vlib_buffer_advance (p0, sizeof (ip6_header_t));
          ip40 = vlib_buffer_get_current (p0);

          /*
           * Encapsulated IPv4 packet
           *   - IPv4 fragmented -> Pass to virtual reassembly unless security check disabled
           *   - Lookup/Rewrite or Fragment node in case of packet > MTU
           * Fragmented IPv6 packet
           * ICMP IPv6 packet
           *   - Error -> Pass to ICMPv6/ICMPv4 relay
           *   - Info -> Pass to IPv6 local
           * Anything else -> drop
           */
          if (PREDICT_TRUE
              (ip60->protocol == IP_PROTOCOL_IP_IN_IP
               && clib_net_to_host_u16 (ip60->payload_length) > 20))
            {
              d0 =
                ip6_map_get_domain (vnet_buffer (p0)->ip.adj_index[VLIB_TX],
                                    (ip4_address_t *) & ip40->
                                    src_address.as_u32, &map_domain_index0,
                                    &error0);
            }
          else if (ip60->protocol == IP_PROTOCOL_ICMP6 &&
                   clib_net_to_host_u16 (ip60->payload_length) >
                   sizeof (icmp46_header_t))
            {
              icmp46_header_t *icmp = (void *) (ip60 + 1);
              next0 = (icmp->type == ICMP6_echo_request
                       || icmp->type ==
                       ICMP6_echo_reply) ? IP6_MAP_NEXT_IP6_LOCAL :
                IP6_MAP_NEXT_IP6_ICMP_RELAY;
            }
          else if (ip60->protocol == IP_PROTOCOL_IPV6_FRAGMENTATION &&
                   (((ip6_frag_hdr_t *) (ip60 + 1))->next_hdr ==
                    IP_PROTOCOL_IP_IN_IP))
            {
              next0 = IP6_MAP_NEXT_IP6_REASS;
            }
          else
            {
              error0 = MAP_ERROR_BAD_PROTOCOL;
            }

          if (d0)
            {
              /* MAP inbound security check */
              ip6_map_security_check (d0, ip40, ip60, &next0, &error0);

              if (PREDICT_TRUE (error0 == MAP_ERROR_NONE &&
                                next0 == IP6_MAP_NEXT_IP4_LOOKUP))
                {
                  if (PREDICT_FALSE
                      (d0->mtu
                       && (clib_host_to_net_u16 (ip40->length) > d0->mtu)))
                    {
                      vnet_buffer (p0)->ip_frag.flags = 0;
                      vnet_buffer (p0)->ip_frag.next_index =
                        IP4_FRAG_NEXT_IP4_LOOKUP;
                      vnet_buffer (p0)->ip_frag.mtu = d0->mtu;
                      next0 = IP6_MAP_NEXT_IP4_FRAGMENT;
                    }
                  else
                    {
                      next0 =
                        ip6_map_ip4_lookup_bypass (p0,
                                                   ip40) ?
                        IP6_MAP_NEXT_IP4_REWRITE : next0;
                    }
                  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_RX,
                                                   thread_index,
                                                   map_domain_index0, 1,
                                                   clib_net_to_host_u16
                                                   (ip40->length));
                }
            }

          if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
            {
              map_trace_t *tr = vlib_add_trace (vm, node, p0, sizeof (*tr));
              tr->map_domain_index = map_domain_index0;
              tr->port = (u16) port0;
            }

          if (mm->icmp6_enabled &&
              (error0 == MAP_ERROR_DECAP_SEC_CHECK
               || error0 == MAP_ERROR_NO_DOMAIN))
            {
              /* Set ICMP parameters */
              vlib_buffer_advance (p0, -sizeof (ip6_header_t));
              icmp6_error_set_vnet_buffer (p0, ICMP6_destination_unreachable,
                                           ICMP6_destination_unreachable_source_address_failed_policy,
                                           0);
              next0 = IP6_MAP_NEXT_ICMP;
            }
          else
            {
              next0 = (error0 == MAP_ERROR_NONE) ? next0 : IP6_MAP_NEXT_DROP;
            }

          /* Reset packet */
          if (next0 == IP6_MAP_NEXT_IP6_LOCAL)
            vlib_buffer_advance (p0, -sizeof (ip6_header_t));

          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_always_inline void
ip6_map_ip6_reass_prepare (vlib_main_t * vm, vlib_node_runtime_t * node,
                           map_ip6_reass_t * r, u32 ** fragments_ready,
                           u32 ** fragments_to_drop)
{
  ip4_header_t *ip40;
  ip6_header_t *ip60;
  ip6_frag_hdr_t *frag0;
  vlib_buffer_t *p0;

  if (!r->ip4_header.ip_version_and_header_length)
    return;

  //The IP header is here, we need to check for packets
  //that can be forwarded
  int i;
  for (i = 0; i < MAP_IP6_REASS_MAX_FRAGMENTS_PER_REASSEMBLY; i++)
    {
      if (r->fragments[i].pi == ~0 ||
          ((!r->fragments[i].next_data_len)
           && (r->fragments[i].next_data_offset != (0xffff))))
        continue;

      p0 = vlib_get_buffer (vm, r->fragments[i].pi);
      ip60 = vlib_buffer_get_current (p0);
      frag0 = (ip6_frag_hdr_t *) (ip60 + 1);
      ip40 = (ip4_header_t *) (frag0 + 1);

      if (ip6_frag_hdr_offset (frag0))
        {
          //Not first fragment, add the IPv4 header
          clib_memcpy (ip40, &r->ip4_header, 20);
        }

#ifdef MAP_IP6_REASS_COUNT_BYTES
      r->forwarded +=
        clib_net_to_host_u16 (ip60->payload_length) - sizeof (*frag0);
#endif

      if (ip6_frag_hdr_more (frag0))
        {
          //Not last fragment, we copy end of next
          clib_memcpy (u8_ptr_add (ip60, p0->current_length),
                       r->fragments[i].next_data, 20);
          p0->current_length += 20;
          ip60->payload_length = u16_net_add (ip60->payload_length, 20);
        }

      if (!ip4_is_fragment (ip40))
        {
          ip40->fragment_id = frag_id_6to4 (frag0->identification);
          ip40->flags_and_fragment_offset =
            clib_host_to_net_u16 (ip6_frag_hdr_offset (frag0));
        }
      else
        {
          ip40->flags_and_fragment_offset =
            clib_host_to_net_u16 (ip4_get_fragment_offset (ip40) +
                                  ip6_frag_hdr_offset (frag0));
        }

      if (ip6_frag_hdr_more (frag0))
        ip40->flags_and_fragment_offset |=
          clib_host_to_net_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS);

      ip40->length =
        clib_host_to_net_u16 (p0->current_length - sizeof (*ip60) -
                              sizeof (*frag0));
      ip40->checksum = ip4_header_checksum (ip40);

      if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
        {
          map_ip6_map_ip6_reass_trace_t *tr =
            vlib_add_trace (vm, node, p0, sizeof (*tr));
          tr->offset = ip4_get_fragment_offset (ip40);
          tr->frag_len = clib_net_to_host_u16 (ip40->length) - sizeof (*ip40);
          tr->out = 1;
        }

      vec_add1 (*fragments_ready, r->fragments[i].pi);
      r->fragments[i].pi = ~0;
      r->fragments[i].next_data_len = 0;
      r->fragments[i].next_data_offset = 0;
      map_main.ip6_reass_buffered_counter--;

      //TODO: Best solution would be that ip6_map handles extension headers
      // and ignores atomic fragment. But in the meantime, let's just copy the header.

      u8 protocol = frag0->next_hdr;
      memmove (u8_ptr_add (ip40, -sizeof (*ip60)), ip60, sizeof (*ip60));
      ((ip6_header_t *) u8_ptr_add (ip40, -sizeof (*ip60)))->protocol =
        protocol;
      vlib_buffer_advance (p0, sizeof (*frag0));
    }
}

void
map_ip6_drop_pi (u32 pi)
{
  vlib_main_t *vm = vlib_get_main ();
  vlib_node_runtime_t *n =
    vlib_node_get_runtime (vm, ip6_map_ip6_reass_node.index);
  vlib_set_next_frame_buffer (vm, n, IP6_MAP_IP6_REASS_NEXT_DROP, pi);
}

void
map_ip4_drop_pi (u32 pi)
{
  vlib_main_t *vm = vlib_get_main ();
  vlib_node_runtime_t *n =
    vlib_node_get_runtime (vm, ip6_map_ip4_reass_node.index);
  vlib_set_next_frame_buffer (vm, n, IP6_MAP_IP4_REASS_NEXT_DROP, pi);
}

/*
 * ip6_reass
 * TODO: We should count the number of successfully
 * transmitted fragment bytes and compare that to the last fragment
 * offset such that we can free the reassembly structure when all fragments
 * have been forwarded.
 */
static uword
ip6_map_ip6_reass (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, ip6_map_ip6_reass_node.index);
  u32 *fragments_to_drop = NULL;
  u32 *fragments_ready = NULL;

  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);

      /* Single loop */
      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 pi0;
          vlib_buffer_t *p0;
          u8 error0 = MAP_ERROR_NONE;
          ip6_header_t *ip60;
          ip6_frag_hdr_t *frag0;
          u16 offset;
          u16 next_offset;
          u16 frag_len;

          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);
          ip60 = vlib_buffer_get_current (p0);
          frag0 = (ip6_frag_hdr_t *) (ip60 + 1);
          offset =
            clib_host_to_net_u16 (frag0->fragment_offset_and_more) & (~7);
          frag_len =
            clib_net_to_host_u16 (ip60->payload_length) - sizeof (*frag0);
          next_offset =
            ip6_frag_hdr_more (frag0) ? (offset + frag_len) : (0xffff);

          //FIXME: Support other extension headers, maybe

          if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
            {
              map_ip6_map_ip6_reass_trace_t *tr =
                vlib_add_trace (vm, node, p0, sizeof (*tr));
              tr->offset = offset;
              tr->frag_len = frag_len;
              tr->out = 0;
            }

          map_ip6_reass_lock ();
          map_ip6_reass_t *r =
            map_ip6_reass_get (&ip60->src_address, &ip60->dst_address,
                               frag0->identification, frag0->next_hdr,
                               &fragments_to_drop);
          //FIXME: Use better error codes
          if (PREDICT_FALSE (!r))
            {
              // Could not create a caching entry
              error0 = MAP_ERROR_FRAGMENT_MEMORY;
            }
          else if (PREDICT_FALSE ((frag_len <= 20 &&
                                   (ip6_frag_hdr_more (frag0) || (!offset)))))
            {
              //Very small fragment are restricted to the last one and
              //can't be the first one
              error0 = MAP_ERROR_FRAGMENT_MALFORMED;
            }
          else
            if (map_ip6_reass_add_fragment
                (r, pi0, offset, next_offset, (u8 *) (frag0 + 1), frag_len))
            {
              map_ip6_reass_free (r, &fragments_to_drop);
              error0 = MAP_ERROR_FRAGMENT_MEMORY;
            }
          else
            {
#ifdef MAP_IP6_REASS_COUNT_BYTES
              if (!ip6_frag_hdr_more (frag0))
                r->expected_total = offset + frag_len;
#endif
              ip6_map_ip6_reass_prepare (vm, node, r, &fragments_ready,
                                         &fragments_to_drop);
#ifdef MAP_IP6_REASS_COUNT_BYTES
              if (r->forwarded >= r->expected_total)
                map_ip6_reass_free (r, &fragments_to_drop);
#endif
            }
          map_ip6_reass_unlock ();

          if (error0 == MAP_ERROR_NONE)
            {
              if (frag_len > 20)
                {
                  //Dequeue the packet
                  n_left_to_next++;
                  to_next--;
                }
              else
                {
                  //All data from that packet was copied no need to keep it, but this is not an error
                  p0->error = error_node->errors[MAP_ERROR_NONE];
                  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
                                                   to_next, n_left_to_next,
                                                   pi0,
                                                   IP6_MAP_IP6_REASS_NEXT_DROP);
                }
            }
          else
            {
              p0->error = error_node->errors[error0];
              vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
                                               n_left_to_next, pi0,
                                               IP6_MAP_IP6_REASS_NEXT_DROP);
            }
        }
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  map_send_all_to_node (vm, fragments_ready, node,
                        &error_node->errors[MAP_ERROR_NONE],
                        IP6_MAP_IP6_REASS_NEXT_IP6_MAP);
  map_send_all_to_node (vm, fragments_to_drop, node,
                        &error_node->errors[MAP_ERROR_FRAGMENT_DROPPED],
                        IP6_MAP_IP6_REASS_NEXT_DROP);

  vec_free (fragments_to_drop);
  vec_free (fragments_ready);
  return frame->n_vectors;
}

/*
 * ip6_ip4_virt_reass
 */
static uword
ip6_map_ip4_reass (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, ip6_map_ip4_reass_node.index);
  map_main_t *mm = &map_main;
  vlib_combined_counter_main_t *cm = mm->domain_counters;
  u32 thread_index = vm->thread_index;
  u32 *fragments_to_drop = NULL;
  u32 *fragments_to_loopback = NULL;

  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);

      /* Single loop */
      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 pi0;
          vlib_buffer_t *p0;
          u8 error0 = MAP_ERROR_NONE;
          map_domain_t *d0;
          ip4_header_t *ip40;
          ip6_header_t *ip60;
          i32 port0 = 0;
          u32 map_domain_index0 = ~0;
          u32 next0 = IP6_MAP_IP4_REASS_NEXT_IP4_LOOKUP;
          u8 cached = 0;

          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);
          ip40 = vlib_buffer_get_current (p0);
          ip60 = ((ip6_header_t *) ip40) - 1;

          d0 =
            ip6_map_get_domain (vnet_buffer (p0)->ip.adj_index[VLIB_TX],
                                (ip4_address_t *) & ip40->src_address.as_u32,
                                &map_domain_index0, &error0);

          map_ip4_reass_lock ();
          //This node only deals with fragmented ip4
          map_ip4_reass_t *r = map_ip4_reass_get (ip40->src_address.as_u32,
                                                  ip40->dst_address.as_u32,
                                                  ip40->fragment_id,
                                                  ip40->protocol,
                                                  &fragments_to_drop);
          if (PREDICT_FALSE (!r))
            {
              // Could not create a caching entry
              error0 = MAP_ERROR_FRAGMENT_MEMORY;
            }
          else if (PREDICT_TRUE (ip4_get_fragment_offset (ip40)))
            {
              // This is a fragment
              if (r->port >= 0)
                {
                  // We know the port already
                  port0 = r->port;
                }
              else if (map_ip4_reass_add_fragment (r, pi0))
                {
                  // Not enough space for caching
                  error0 = MAP_ERROR_FRAGMENT_MEMORY;
                  map_ip4_reass_free (r, &fragments_to_drop);
                }
              else
                {
                  cached = 1;
                }
            }
          else if ((port0 = ip4_get_port (ip40, 1)) == 0)
            {
              // Could not find port from first fragment. Stop reassembling.
              error0 = MAP_ERROR_BAD_PROTOCOL;
              port0 = 0;
              map_ip4_reass_free (r, &fragments_to_drop);
            }
          else
            {
              // Found port. Remember it and loopback saved fragments
              r->port = port0;
              map_ip4_reass_get_fragments (r, &fragments_to_loopback);
            }

#ifdef MAP_IP4_REASS_COUNT_BYTES
          if (!cached && r)
            {
              r->forwarded += clib_host_to_net_u16 (ip40->length) - 20;
              if (!ip4_get_fragment_more (ip40))
                r->expected_total =
                  ip4_get_fragment_offset (ip40) * 8 +
                  clib_host_to_net_u16 (ip40->length) - 20;
              if (r->forwarded >= r->expected_total)
                map_ip4_reass_free (r, &fragments_to_drop);
            }
#endif

          map_ip4_reass_unlock ();

          if (PREDICT_TRUE (error0 == MAP_ERROR_NONE))
            error0 =
              ip6_map_sec_check (d0, port0, ip40,
                                 ip60) ? MAP_ERROR_NONE :
              MAP_ERROR_DECAP_SEC_CHECK;

          if (PREDICT_FALSE
              (d0->mtu && (clib_host_to_net_u16 (ip40->length) > d0->mtu)
               && error0 == MAP_ERROR_NONE && !cached))
            {
              vnet_buffer (p0)->ip_frag.flags = 0;
              vnet_buffer (p0)->ip_frag.next_index = IP4_FRAG_NEXT_IP4_LOOKUP;
              vnet_buffer (p0)->ip_frag.mtu = d0->mtu;
              next0 = IP6_MAP_IP4_REASS_NEXT_IP4_FRAGMENT;
            }

          if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
            {
              map_ip6_map_ip4_reass_trace_t *tr =
                vlib_add_trace (vm, node, p0, sizeof (*tr));
              tr->map_domain_index = map_domain_index0;
              tr->port = port0;
              tr->cached = cached;
            }

          if (cached)
            {
              //Dequeue the packet
              n_left_to_next++;
              to_next--;
            }
          else
            {
              if (error0 == MAP_ERROR_NONE)
                vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_RX,
                                                 thread_index,
                                                 map_domain_index0, 1,
                                                 clib_net_to_host_u16
                                                 (ip40->length));
              next0 =
                (error0 ==
                 MAP_ERROR_NONE) ? next0 : IP6_MAP_IP4_REASS_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);
            }

          //Loopback when we reach the end of the inpu vector
          if (n_left_from == 0 && vec_len (fragments_to_loopback))
            {
              from = vlib_frame_vector_args (frame);
              u32 len = vec_len (fragments_to_loopback);
              if (len <= VLIB_FRAME_SIZE)
                {
                  clib_memcpy (from, fragments_to_loopback,
                               sizeof (u32) * len);
                  n_left_from = len;
                  vec_reset_length (fragments_to_loopback);
                }
              else
                {
                  clib_memcpy (from,
                               fragments_to_loopback + (len -
                                                        VLIB_FRAME_SIZE),
                               sizeof (u32) * VLIB_FRAME_SIZE);
                  n_left_from = VLIB_FRAME_SIZE;
                  _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
                }
            }
        }
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }
  map_send_all_to_node (vm, fragments_to_drop, node,
                        &error_node->errors[MAP_ERROR_FRAGMENT_DROPPED],
                        IP6_MAP_IP4_REASS_NEXT_DROP);

  vec_free (fragments_to_drop);
  vec_free (fragments_to_loopback);
  return frame->n_vectors;
}

/*
 * ip6_icmp_relay
 */
static uword
ip6_map_icmp_relay (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, ip6_map_icmp_relay_node.index);
  map_main_t *mm = &map_main;
  u32 thread_index = vm->thread_index;
  u16 *fragment_ids, *fid;

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

  /* Get random fragment IDs for replies. */
  fid = fragment_ids =
    clib_random_buffer_get_data (&vm->random_buffer,
                                 n_left_from * sizeof (fragment_ids[0]));

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

      /* Single loop */
      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 pi0;
          vlib_buffer_t *p0;
          u8 error0 = MAP_ERROR_NONE;
          ip6_header_t *ip60;
          u32 next0 = IP6_ICMP_RELAY_NEXT_IP4_LOOKUP;
          u32 mtu;

          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);
          ip60 = vlib_buffer_get_current (p0);
          u16 tlen = clib_net_to_host_u16 (ip60->payload_length);

          /*
           * In:
           *  IPv6 header           (40)
           *  ICMPv6 header          (8)
           *  IPv6 header           (40)
           *  Original IPv4 header / packet
           * Out:
           *  New IPv4 header
           *  New ICMP header
           *  Original IPv4 header / packet
           */

          /* Need at least ICMP(8) + IPv6(40) + IPv4(20) + L4 header(8) */
          if (tlen < 76)
            {
              error0 = MAP_ERROR_ICMP_RELAY;
              goto error;
            }

          icmp46_header_t *icmp60 = (icmp46_header_t *) (ip60 + 1);
          ip6_header_t *inner_ip60 = (ip6_header_t *) (icmp60 + 2);

          if (inner_ip60->protocol != IP_PROTOCOL_IP_IN_IP)
            {
              error0 = MAP_ERROR_ICMP_RELAY;
              goto error;
            }

          ip4_header_t *inner_ip40 = (ip4_header_t *) (inner_ip60 + 1);
          vlib_buffer_advance (p0, 60); /* sizeof ( IPv6 + ICMP + IPv6 - IPv4 - ICMP ) */
          ip4_header_t *new_ip40 = vlib_buffer_get_current (p0);
          icmp46_header_t *new_icmp40 = (icmp46_header_t *) (new_ip40 + 1);

          /*
           * Relay according to RFC2473, section 8.3
           */
          switch (icmp60->type)
            {
            case ICMP6_destination_unreachable:
            case ICMP6_time_exceeded:
            case ICMP6_parameter_problem:
              /* Type 3 - destination unreachable, Code 1 - host unreachable */
              new_icmp40->type = ICMP4_destination_unreachable;
              new_icmp40->code =
                ICMP4_destination_unreachable_destination_unreachable_host;
              break;

            case ICMP6_packet_too_big:
              /* Type 3 - destination unreachable, Code 4 - packet too big */
              /* Potential TODO: Adjust domain tunnel MTU based on the value received here */
              mtu = clib_net_to_host_u32 (*((u32 *) (icmp60 + 1)));

              /* Check DF flag */
              if (!
                  (inner_ip40->flags_and_fragment_offset &
                   clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT)))
                {
                  error0 = MAP_ERROR_ICMP_RELAY;
                  goto error;
                }

              new_icmp40->type = ICMP4_destination_unreachable;
              new_icmp40->code =
                ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set;
              *((u32 *) (new_icmp40 + 1)) =
                clib_host_to_net_u32 (mtu < 1280 ? 1280 : mtu);
              break;

            default:
              error0 = MAP_ERROR_ICMP_RELAY;
              break;
            }

          /*
           * Ensure the total ICMP packet is no longer than 576 bytes (RFC1812)
           */
          new_ip40->ip_version_and_header_length = 0x45;
          new_ip40->tos = 0;
          u16 nlen = (tlen - 20) > 576 ? 576 : tlen - 20;
          new_ip40->length = clib_host_to_net_u16 (nlen);
          new_ip40->fragment_id = fid[0];
          fid++;
          new_ip40->ttl = 64;
          new_ip40->protocol = IP_PROTOCOL_ICMP;
          new_ip40->src_address = mm->icmp4_src_address;
          new_ip40->dst_address = inner_ip40->src_address;
          new_ip40->checksum = ip4_header_checksum (new_ip40);

          new_icmp40->checksum = 0;
          ip_csum_t sum = ip_incremental_checksum (0, new_icmp40, nlen - 20);
          new_icmp40->checksum = ~ip_csum_fold (sum);

          vlib_increment_simple_counter (&mm->icmp_relayed, thread_index, 0,
                                         1);

        error:
          if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
            {
              map_trace_t *tr = vlib_add_trace (vm, node, p0, sizeof (*tr));
              tr->map_domain_index = 0;
              tr->port = 0;
            }

          next0 =
            (error0 == MAP_ERROR_NONE) ? next0 : IP6_ICMP_RELAY_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 char *map_error_strings[] = {
#define _(sym,string) string,
  foreach_map_error
#undef _
};

/* *INDENT-OFF* */
VLIB_REGISTER_NODE(ip6_map_node) = {
  .function = ip6_map,
  .name = "ip6-map",
  .vector_size = sizeof(u32),
  .format_trace = format_map_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = MAP_N_ERROR,
  .error_strings = map_error_strings,

  .n_next_nodes = IP6_MAP_N_NEXT,
  .next_nodes = {
    [IP6_MAP_NEXT_IP4_LOOKUP] = "ip4-lookup",
#ifdef MAP_SKIP_IP6_LOOKUP
    [IP6_MAP_NEXT_IP4_REWRITE] = "ip4-load-balance",
#endif
    [IP6_MAP_NEXT_IP6_REASS] = "ip6-map-ip6-reass",
    [IP6_MAP_NEXT_IP4_REASS] = "ip6-map-ip4-reass",
    [IP6_MAP_NEXT_IP4_FRAGMENT] = "ip4-frag",
    [IP6_MAP_NEXT_IP6_ICMP_RELAY] = "ip6-map-icmp-relay",
    [IP6_MAP_NEXT_IP6_LOCAL] = "ip6-local",
    [IP6_MAP_NEXT_DROP] = "error-drop",
    [IP6_MAP_NEXT_ICMP] = "ip6-icmp-error",
  },
};
/* *INDENT-ON* */

/* *INDENT-OFF* */
VLIB_REGISTER_NODE(ip6_map_ip6_reass_node) = {
  .function = ip6_map_ip6_reass,
  .name = "ip6-map-ip6-reass",
  .vector_size = sizeof(u32),
  .format_trace = format_ip6_map_ip6_reass_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = MAP_N_ERROR,
  .error_strings = map_error_strings,
  .n_next_nodes = IP6_MAP_IP6_REASS_N_NEXT,
  .next_nodes = {
    [IP6_MAP_IP6_REASS_NEXT_IP6_MAP] = "ip6-map",
    [IP6_MAP_IP6_REASS_NEXT_DROP] = "error-drop",
  },
};
/* *INDENT-ON* */

/* *INDENT-OFF* */
VLIB_REGISTER_NODE(ip6_map_ip4_reass_node) = {
  .function = ip6_map_ip4_reass,
  .name = "ip6-map-ip4-reass",
  .vector_size = sizeof(u32),
  .format_trace = format_ip6_map_ip4_reass_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = MAP_N_ERROR,
  .error_strings = map_error_strings,
  .n_next_nodes = IP6_MAP_IP4_REASS_N_NEXT,
  .next_nodes = {
    [IP6_MAP_IP4_REASS_NEXT_IP4_LOOKUP] = "ip4-lookup",
    [IP6_MAP_IP4_REASS_NEXT_IP4_FRAGMENT] = "ip4-frag",
    [IP6_MAP_IP4_REASS_NEXT_DROP] = "error-drop",
  },
};
/* *INDENT-ON* */

/* *INDENT-OFF* */
VLIB_REGISTER_NODE(ip6_map_icmp_relay_node, static) = {
  .function = ip6_map_icmp_relay,
  .name = "ip6-map-icmp-relay",
  .vector_size = sizeof(u32),
  .format_trace = format_map_trace, //FIXME
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = MAP_N_ERROR,
  .error_strings = map_error_strings,
  .n_next_nodes = IP6_ICMP_RELAY_N_NEXT,
  .next_nodes = {
    [IP6_ICMP_RELAY_NEXT_IP4_LOOKUP] = "ip4-lookup",
    [IP6_ICMP_RELAY_NEXT_DROP] = "error-drop",
  },
};
/* *INDENT-ON* */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */