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>
#include <vnet/ip/reass/ip4_sv_reass.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_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_post_ip4_reass_next_e
{
  IP6_MAP_POST_IP4_REASS_NEXT_IP4_LOOKUP,
  IP6_MAP_POST_IP4_REASS_NEXT_IP4_FRAGMENT,
  IP6_MAP_POST_IP4_REASS_NEXT_DROP,
  IP6_MAP_POST_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_post_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_post_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, clib_net_to_host_u16 (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, vlib_buffer_t * b0,
                        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
            {
              if (mm->sec_check_frag)
                {
                  vnet_buffer (b0)->ip.reass.next_index =
                    map_main.ip4_sv_reass_custom_next_index;
                  *next = IP6_MAP_NEXT_IP4_REASS;
                }
            }
        }
    }
}

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 =
                ip4_map_get_domain ((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)
            {
              error0 = MAP_ERROR_FRAGMENTED;
            }
          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 =
                ip4_map_get_domain ((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)
            {
              error1 = MAP_ERROR_FRAGMENTED;
            }
          else
            {
              error1 = MAP_ERROR_BAD_PROTOCOL;
            }

          if (d0)
            {
              /* MAP inbound security check */
              ip6_map_security_check (d0, p0, 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 =
                        IP_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, p1, 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 =
                        IP_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_add_trace (vm, node, p0, map_domain_index0, port0);
            }

          if (PREDICT_FALSE (p1->flags & VLIB_BUFFER_IS_TRACED))
            {
              map_add_trace (vm, node, p1, map_domain_index1, 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 =
                ip4_map_get_domain ((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))
            {
              error0 = MAP_ERROR_FRAGMENTED;
            }
          else
            {
              /* XXX: Move get_domain to ip6_get_domain lookup on source */
              //error0 = MAP_ERROR_BAD_PROTOCOL;
              vlib_buffer_advance (p0, -sizeof (ip6_header_t));
              vnet_feature_next (&next0, p0);
            }

          if (d0)
            {
              /* MAP inbound security check */
              ip6_map_security_check (d0, p0, 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 =
                        IP_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_add_trace (vm, node, p0, map_domain_index0, 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;
}


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);
}

/*
 * ip6_map_post_ip4_reass
 */
static uword
ip6_map_post_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_post_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;

  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_POST_IP4_REASS_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);
          ip40 = vlib_buffer_get_current (p0);
          ip60 = ((ip6_header_t *) ip40) - 1;

          d0 =
            ip4_map_get_domain ((ip4_address_t *) & ip40->src_address.as_u32,
                                &map_domain_index0, &error0);

          port0 = vnet_buffer (p0)->ip.reass.l4_src_port;

          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
              (error0 == MAP_ERROR_NONE &&
               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 = IP_FRAG_NEXT_IP4_LOOKUP;
              vnet_buffer (p0)->ip_frag.mtu = d0->mtu;
              next0 = IP6_MAP_POST_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;
            }

          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_POST_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);

        }
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }
  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* */
VNET_FEATURE_INIT (ip6_map_feature, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "ip6-map",
  .runs_before = VNET_FEATURES ("ip6-flow-classify"),
  .runs_after = VNET_FEATURES ("ip6-full-reassembly-feature"),
};

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_IP4_REASS] = "ip4-sv-reassembly-custom-next",
    [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_post_ip4_reass_node) = {
  .function = ip6_map_post_ip4_reass,
  .name = "ip6-map-post-ip4-reass",
  .vector_size = sizeof(u32),
  .format_trace = format_ip6_map_post_ip4_reass_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = MAP_N_ERROR,
  .error_strings = map_error_strings,
  .n_next_nodes = IP6_MAP_POST_IP4_REASS_N_NEXT,
  .next_nodes = {
    [IP6_MAP_POST_IP4_REASS_NEXT_IP4_LOOKUP] = "ip4-lookup",
    [IP6_MAP_POST_IP4_REASS_NEXT_IP4_FRAGMENT] = "ip4-frag",
    [IP6_MAP_POST_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* */

clib_error_t *
ip6_map_init (vlib_main_t * vm)
{
  map_main.ip4_sv_reass_custom_next_index =
    ip4_sv_reass_custom_register_next_node
    (ip6_map_post_ip4_reass_node.index);
  return 0;
}

VLIB_INIT_FUNCTION (ip6_map_init) =
{
.runs_after = VLIB_INITS ("map_init"),};

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