ip4_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.
 */
/*
 * Defines used for testing various optimisation schemes
 */
#define MAP_ENCAP_DUAL 0

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

vlib_node_registration_t ip4_map_reass_node;

enum ip4_map_next_e
{
  IP4_MAP_NEXT_IP6_LOOKUP,
#ifdef MAP_SKIP_IP6_LOOKUP
  IP4_MAP_NEXT_IP6_REWRITE,
#endif
  IP4_MAP_NEXT_IP4_FRAGMENT,
  IP4_MAP_NEXT_IP6_FRAGMENT,
  IP4_MAP_NEXT_REASS,
  IP4_MAP_NEXT_ICMP_ERROR,
  IP4_MAP_NEXT_DROP,
  IP4_MAP_N_NEXT,
};

enum ip4_map_reass_next_t
{
  IP4_MAP_REASS_NEXT_IP6_LOOKUP,
  IP4_MAP_REASS_NEXT_IP4_FRAGMENT,
  IP4_MAP_REASS_NEXT_DROP,
  IP4_MAP_REASS_N_NEXT,
};

typedef struct
{
  u32 map_domain_index;
  u16 port;
  u8 cached;
} map_ip4_map_reass_trace_t;

u8 *
format_ip4_map_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_ip4_map_reass_trace_t *t = va_arg (*args, map_ip4_map_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");
}

/*
 * ip4_map_get_port
 */
u16
ip4_map_get_port (ip4_header_t * ip, map_dir_e dir)
{
  /* Find port information */
  if (PREDICT_TRUE ((ip->protocol == IP_PROTOCOL_TCP) ||
                    (ip->protocol == IP_PROTOCOL_UDP)))
    {
      udp_header_t *udp = (void *) (ip + 1);
      return (dir == MAP_SENDER ? udp->src_port : udp->dst_port);
    }
  else if (ip->protocol == IP_PROTOCOL_ICMP)
    {
      /*
       * 1) ICMP Echo request or Echo reply
       * 2) ICMP Error with inner packet being UDP or TCP
       * 3) ICMP Error with inner packet being ICMP Echo request or Echo reply
       */
      icmp46_header_t *icmp = (void *) (ip + 1);
      if (icmp->type == ICMP4_echo_request || icmp->type == ICMP4_echo_reply)
        {
          return *((u16 *) (icmp + 1));
        }
      else if (clib_net_to_host_u16 (ip->length) >= 56)
        {                       // IP + ICMP + IP + L4 header
          ip4_header_t *icmp_ip = (ip4_header_t *) (icmp + 2);
          if (PREDICT_TRUE ((icmp_ip->protocol == IP_PROTOCOL_TCP) ||
                            (icmp_ip->protocol == IP_PROTOCOL_UDP)))
            {
              udp_header_t *udp = (void *) (icmp_ip + 1);
              return (dir == MAP_SENDER ? udp->dst_port : udp->src_port);
            }
          else if (icmp_ip->protocol == IP_PROTOCOL_ICMP)
            {
              icmp46_header_t *inner_icmp = (void *) (icmp_ip + 1);
              if (inner_icmp->type == ICMP4_echo_request
                  || inner_icmp->type == ICMP4_echo_reply)
                return (*((u16 *) (inner_icmp + 1)));
            }
        }
    }
  return (0);
}

static_always_inline u16
ip4_map_port_and_security_check (map_domain_t * d, ip4_header_t * ip,
                                 u32 * next, u8 * error)
{
  u16 port = 0;

  if (d->psid_length > 0)
    {
      if (ip4_get_fragment_offset (ip) == 0)
        {
          if (PREDICT_FALSE
              ((ip->ip_version_and_header_length != 0x45)
               || clib_host_to_net_u16 (ip->length) < 28))
            {
              return 0;
            }
          port = ip4_map_get_port (ip, MAP_RECEIVER);
          if (port)
            {
              /* Verify that port is not among the well-known ports */
              if ((d->psid_offset > 0)
                  && (clib_net_to_host_u16 (port) <
                      (0x1 << (16 - d->psid_offset))))
                {
                  *error = MAP_ERROR_ENCAP_SEC_CHECK;
                }
              else
                {
                  if (ip4_get_fragment_more (ip))
                    *next = IP4_MAP_NEXT_REASS;
                  return (port);
                }
            }
          else
            {
              *error = MAP_ERROR_BAD_PROTOCOL;
            }
        }
      else
        {
          *next = IP4_MAP_NEXT_REASS;
        }
    }
  return (0);
}

/*
 * ip4_map_vtcfl
 */
static_always_inline u32
ip4_map_vtcfl (ip4_header_t * ip4, vlib_buffer_t * p)
{
  map_main_t *mm = &map_main;
  u8 tc = mm->tc_copy ? ip4->tos : mm->tc;
  u32 vtcfl = 0x6 << 28;
  vtcfl |= tc << 20;
  vtcfl |= vnet_buffer (p)->ip.flow_hash & 0x000fffff;

  return (clib_host_to_net_u32 (vtcfl));
}

static_always_inline bool
ip4_map_ip6_lookup_bypass (vlib_buffer_t * p0, ip4_header_t * ip)
{
#ifdef MAP_SKIP_IP6_LOOKUP
  if (FIB_NODE_INDEX_INVALID != pre_resolved[FIB_PROTOCOL_IP6].fei)
    {
      vnet_buffer (p0)->ip.adj_index[VLIB_TX] =
        pre_resolved[FIB_PROTOCOL_IP6].dpo.dpoi_index;
      return (true);
    }
#endif
  return (false);
}

/*
 * ip4_map_ttl
 */
static inline void
ip4_map_decrement_ttl (ip4_header_t * ip, u8 * error)
{
  i32 ttl = ip->ttl;

  /* Input node should have reject packets with ttl 0. */
  ASSERT (ip->ttl > 0);

  u32 checksum = ip->checksum + clib_host_to_net_u16 (0x0100);
  checksum += checksum >= 0xffff;
  ip->checksum = checksum;
  ttl -= 1;
  ip->ttl = ttl;
  *error = ttl <= 0 ? IP4_ERROR_TIME_EXPIRED : *error;

  /* Verify checksum. */
  ASSERT (ip->checksum == ip4_header_checksum (ip));
}

static u32
ip4_map_fragment (vlib_buffer_t * b, u16 mtu, bool df, u8 * error)
{
  map_main_t *mm = &map_main;

  if (mm->frag_inner)
    {
      ip_frag_set_vnet_buffer (b, sizeof (ip6_header_t), mtu,
                               IP4_FRAG_NEXT_IP6_LOOKUP,
                               IP_FRAG_FLAG_IP6_HEADER);
      return (IP4_MAP_NEXT_IP4_FRAGMENT);
    }
  else
    {
      if (df && !mm->frag_ignore_df)
        {
          icmp4_error_set_vnet_buffer (b, ICMP4_destination_unreachable,
                                       ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set,
                                       mtu);
          vlib_buffer_advance (b, sizeof (ip6_header_t));
          *error = MAP_ERROR_DF_SET;
          return (IP4_MAP_NEXT_ICMP_ERROR);
        }
      ip_frag_set_vnet_buffer (b, 0, mtu, IP6_FRAG_NEXT_IP6_LOOKUP,
                               IP_FRAG_FLAG_IP6_HEADER);
      return (IP4_MAP_NEXT_IP6_FRAGMENT);
    }
}

/*
 * ip4_map
 */
static uword
ip4_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, ip4_map_node.index);
  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;
  map_main_t *mm = &map_main;
  vlib_combined_counter_main_t *cm = mm->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);

      /* Dual loop */
      while (n_left_from >= 4 && n_left_to_next >= 2)
        {
          u32 pi0, pi1;
          vlib_buffer_t *p0, *p1;
          map_domain_t *d0, *d1;
          u8 error0 = MAP_ERROR_NONE, error1 = MAP_ERROR_NONE;
          ip4_header_t *ip40, *ip41;
          u16 port0 = 0, port1 = 0;
          ip6_header_t *ip6h0, *ip6h1;
          u32 map_domain_index0 = ~0, map_domain_index1 = ~0;
          u32 next0 = IP4_MAP_NEXT_IP6_LOOKUP, next1 =
            IP4_MAP_NEXT_IP6_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, STORE);
            vlib_prefetch_buffer_header (p3, STORE);
            /* IPv4 + 8 = 28. possibly plus -40 */
            CLIB_PREFETCH (p2->data - 40, 68, STORE);
            CLIB_PREFETCH (p3->data - 40, 68, STORE);
          }

          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);
          ip40 = vlib_buffer_get_current (p0);
          ip41 = vlib_buffer_get_current (p1);
          d0 =
            ip4_map_get_domain (vnet_buffer (p0)->ip.adj_index[VLIB_TX],
                                &map_domain_index0);
          d1 =
            ip4_map_get_domain (vnet_buffer (p1)->ip.adj_index[VLIB_TX],
                                &map_domain_index1);
          ASSERT (d0);
          ASSERT (d1);

          /*
           * Shared IPv4 address
           */
          port0 = ip4_map_port_and_security_check (d0, ip40, &next0, &error0);
          port1 = ip4_map_port_and_security_check (d1, ip41, &next1, &error1);

          /* Decrement IPv4 TTL */
          ip4_map_decrement_ttl (ip40, &error0);
          ip4_map_decrement_ttl (ip41, &error1);
          bool df0 =
            ip40->flags_and_fragment_offset &
            clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);
          bool df1 =
            ip41->flags_and_fragment_offset &
            clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);

          /* MAP calc */
          u32 da40 = clib_net_to_host_u32 (ip40->dst_address.as_u32);
          u32 da41 = clib_net_to_host_u32 (ip41->dst_address.as_u32);
          u16 dp40 = clib_net_to_host_u16 (port0);
          u16 dp41 = clib_net_to_host_u16 (port1);
          u64 dal60 = map_get_pfx (d0, da40, dp40);
          u64 dal61 = map_get_pfx (d1, da41, dp41);
          u64 dar60 = map_get_sfx (d0, da40, dp40);
          u64 dar61 = map_get_sfx (d1, da41, dp41);
          if (dal60 == 0 && dar60 == 0 && error0 == MAP_ERROR_NONE
              && next0 != IP4_MAP_NEXT_REASS)
            error0 = MAP_ERROR_NO_BINDING;
          if (dal61 == 0 && dar61 == 0 && error1 == MAP_ERROR_NONE
              && next1 != IP4_MAP_NEXT_REASS)
            error1 = MAP_ERROR_NO_BINDING;

          /* construct ipv6 header */
          vlib_buffer_advance (p0, -sizeof (ip6_header_t));
          vlib_buffer_advance (p1, -sizeof (ip6_header_t));
          ip6h0 = vlib_buffer_get_current (p0);
          ip6h1 = vlib_buffer_get_current (p1);
          vnet_buffer (p0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
          vnet_buffer (p1)->sw_if_index[VLIB_TX] = (u32) ~ 0;

          ip6h0->ip_version_traffic_class_and_flow_label =
            ip4_map_vtcfl (ip40, p0);
          ip6h1->ip_version_traffic_class_and_flow_label =
            ip4_map_vtcfl (ip41, p1);
          ip6h0->payload_length = ip40->length;
          ip6h1->payload_length = ip41->length;
          ip6h0->protocol = IP_PROTOCOL_IP_IN_IP;
          ip6h1->protocol = IP_PROTOCOL_IP_IN_IP;
          ip6h0->hop_limit = 0x40;
          ip6h1->hop_limit = 0x40;
          ip6h0->src_address = d0->ip6_src;
          ip6h1->src_address = d1->ip6_src;
          ip6h0->dst_address.as_u64[0] = clib_host_to_net_u64 (dal60);
          ip6h0->dst_address.as_u64[1] = clib_host_to_net_u64 (dar60);
          ip6h1->dst_address.as_u64[0] = clib_host_to_net_u64 (dal61);
          ip6h1->dst_address.as_u64[1] = clib_host_to_net_u64 (dar61);

          /*
           * Determine next node. Can be one of:
           * ip6-lookup, ip6-rewrite, ip4-fragment, ip4-virtreass, error-drop
           */
          if (PREDICT_TRUE (error0 == MAP_ERROR_NONE))
            {
              if (PREDICT_FALSE
                  (d0->mtu
                   && (clib_net_to_host_u16 (ip6h0->payload_length) +
                       sizeof (*ip6h0) > d0->mtu)))
                {
                  next0 = ip4_map_fragment (p0, d0->mtu, df0, &error0);
                }
              else
                {
                  next0 =
                    ip4_map_ip6_lookup_bypass (p0,
                                               ip40) ?
                    IP4_MAP_NEXT_IP6_REWRITE : next0;
                  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
                                                   cpu_index,
                                                   map_domain_index0, 1,
                                                   clib_net_to_host_u16
                                                   (ip6h0->payload_length) +
                                                   40);
                }
            }
          else
            {
              next0 = IP4_MAP_NEXT_DROP;
            }

          /*
           * Determine next node. Can be one of:
           * ip6-lookup, ip6-rewrite, ip4-fragment, ip4-virtreass, error-drop
           */
          if (PREDICT_TRUE (error1 == MAP_ERROR_NONE))
            {
              if (PREDICT_FALSE
                  (d1->mtu
                   && (clib_net_to_host_u16 (ip6h1->payload_length) +
                       sizeof (*ip6h1) > d1->mtu)))
                {
                  next1 = ip4_map_fragment (p1, d1->mtu, df1, &error1);
                }
              else
                {
                  next1 =
                    ip4_map_ip6_lookup_bypass (p1,
                                               ip41) ?
                    IP4_MAP_NEXT_IP6_REWRITE : next1;
                  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
                                                   cpu_index,
                                                   map_domain_index1, 1,
                                                   clib_net_to_host_u16
                                                   (ip6h1->payload_length) +
                                                   40);
                }
            }
          else
            {
              next1 = IP4_MAP_NEXT_DROP;
            }

          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;
            }

          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);
        }

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 pi0;
          vlib_buffer_t *p0;
          map_domain_t *d0;
          u8 error0 = MAP_ERROR_NONE;
          ip4_header_t *ip40;
          u16 port0 = 0;
          ip6_header_t *ip6h0;
          u32 next0 = IP4_MAP_NEXT_IP6_LOOKUP;
          u32 map_domain_index0 = ~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);
          d0 =
            ip4_map_get_domain (vnet_buffer (p0)->ip.adj_index[VLIB_TX],
                                &map_domain_index0);
          ASSERT (d0);

          /*
           * Shared IPv4 address
           */
          port0 = ip4_map_port_and_security_check (d0, ip40, &next0, &error0);

          /* Decrement IPv4 TTL */
          ip4_map_decrement_ttl (ip40, &error0);
          bool df0 =
            ip40->flags_and_fragment_offset &
            clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);

          /* MAP calc */
          u32 da40 = clib_net_to_host_u32 (ip40->dst_address.as_u32);
          u16 dp40 = clib_net_to_host_u16 (port0);
          u64 dal60 = map_get_pfx (d0, da40, dp40);
          u64 dar60 = map_get_sfx (d0, da40, dp40);
          if (dal60 == 0 && dar60 == 0 && error0 == MAP_ERROR_NONE
              && next0 != IP4_MAP_NEXT_REASS)
            error0 = MAP_ERROR_NO_BINDING;

          /* construct ipv6 header */
          vlib_buffer_advance (p0, -(sizeof (ip6_header_t)));
          ip6h0 = vlib_buffer_get_current (p0);
          vnet_buffer (p0)->sw_if_index[VLIB_TX] = (u32) ~ 0;

          ip6h0->ip_version_traffic_class_and_flow_label =
            ip4_map_vtcfl (ip40, p0);
          ip6h0->payload_length = ip40->length;
          ip6h0->protocol = IP_PROTOCOL_IP_IN_IP;
          ip6h0->hop_limit = 0x40;
          ip6h0->src_address = d0->ip6_src;
          ip6h0->dst_address.as_u64[0] = clib_host_to_net_u64 (dal60);
          ip6h0->dst_address.as_u64[1] = clib_host_to_net_u64 (dar60);

          /*
           * Determine next node. Can be one of:
           * ip6-lookup, ip6-rewrite, ip4-fragment, ip4-virtreass, error-drop
           */
          if (PREDICT_TRUE (error0 == MAP_ERROR_NONE))
            {
              if (PREDICT_FALSE
                  (d0->mtu
                   && (clib_net_to_host_u16 (ip6h0->payload_length) +
                       sizeof (*ip6h0) > d0->mtu)))
                {
                  next0 = ip4_map_fragment (p0, d0->mtu, df0, &error0);
                }
              else
                {
                  next0 =
                    ip4_map_ip6_lookup_bypass (p0,
                                               ip40) ?
                    IP4_MAP_NEXT_IP6_REWRITE : next0;
                  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
                                                   cpu_index,
                                                   map_domain_index0, 1,
                                                   clib_net_to_host_u16
                                                   (ip6h0->payload_length) +
                                                   40);
                }
            }
          else
            {
              next0 = IP4_MAP_NEXT_DROP;
            }

          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;
            }

          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;
}

/*
 * ip4_map_reass
 */
static uword
ip4_map_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, ip4_map_reass_node.index);
  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;
  map_main_t *mm = &map_main;
  vlib_combined_counter_main_t *cm = mm->domain_counters;
  u32 cpu_index = os_get_cpu_number ();
  u32 *fragments_to_drop = NULL;
  u32 *fragments_to_loopback = NULL;

  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;
          map_domain_t *d0;
          u8 error0 = MAP_ERROR_NONE;
          ip4_header_t *ip40;
          i32 port0 = 0;
          ip6_header_t *ip60;
          u32 next0 = IP4_MAP_REASS_NEXT_IP6_LOOKUP;
          u32 map_domain_index0;
          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);
          ip60 = vlib_buffer_get_current (p0);
          ip40 = (ip4_header_t *) (ip60 + 1);
          d0 =
            ip4_map_get_domain (vnet_buffer (p0)->ip.adj_index[VLIB_TX],
                                &map_domain_index0);

          map_ip4_reass_lock ();
          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)))
            {
              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, MAP_RECEIVER, p0->current_length)) < 0)
            {
              // Could not find port. We'll free the reassembly.
              error0 = MAP_ERROR_BAD_PROTOCOL;
              port0 = 0;
              map_ip4_reass_free (r, &fragments_to_drop);
            }
          else
            {
              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 ();

          // NOTE: Most operations have already been performed by ip4_map
          // All we need is the right destination address
          ip60->dst_address.as_u64[0] =
            map_get_pfx_net (d0, ip40->dst_address.as_u32, port0);
          ip60->dst_address.as_u64[1] =
            map_get_sfx_net (d0, ip40->dst_address.as_u32, port0);

          if (PREDICT_FALSE
              (d0->mtu
               && (clib_net_to_host_u16 (ip60->payload_length) +
                   sizeof (*ip60) > d0->mtu)))
            {
              vnet_buffer (p0)->ip_frag.header_offset = sizeof (*ip60);
              vnet_buffer (p0)->ip_frag.next_index = IP4_FRAG_NEXT_IP6_LOOKUP;
              vnet_buffer (p0)->ip_frag.mtu = d0->mtu;
              vnet_buffer (p0)->ip_frag.flags = IP_FRAG_FLAG_IP6_HEADER;
              next0 = IP4_MAP_REASS_NEXT_IP4_FRAGMENT;
            }

          if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
            {
              map_ip4_map_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_TX,
                                                 cpu_index, map_domain_index0,
                                                 1,
                                                 clib_net_to_host_u16
                                                 (ip60->payload_length) + 40);
              next0 =
                (error0 == MAP_ERROR_NONE) ? next0 : IP4_MAP_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],
                        IP4_MAP_REASS_NEXT_DROP);

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

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

/* *INDENT-OFF* */
VLIB_REGISTER_NODE(ip4_map_node) = {
  .function = ip4_map,
  .name = "ip4-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 = IP4_MAP_N_NEXT,
  .next_nodes = {
    [IP4_MAP_NEXT_IP6_LOOKUP] = "ip6-lookup",
#ifdef MAP_SKIP_IP6_LOOKUP
    [IP4_MAP_NEXT_IP6_REWRITE] = "ip6-load-balance",
#endif
    [IP4_MAP_NEXT_IP4_FRAGMENT] = "ip4-frag",
    [IP4_MAP_NEXT_IP6_FRAGMENT] = "ip6-frag",
    [IP4_MAP_NEXT_REASS] = "ip4-map-reass",
    [IP4_MAP_NEXT_ICMP_ERROR] = "ip4-icmp-error",
    [IP4_MAP_NEXT_DROP] = "error-drop",
  },
};
/* *INDENT-ON* */

/* *INDENT-OFF* */
VLIB_REGISTER_NODE(ip4_map_reass_node) = {
  .function = ip4_map_reass,
  .name = "ip4-map-reass",
  .vector_size = sizeof(u32),
  .format_trace = format_ip4_map_reass_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = MAP_N_ERROR,
  .error_strings = map_error_strings,

  .n_next_nodes = IP4_MAP_REASS_N_NEXT,
  .next_nodes = {
    [IP4_MAP_REASS_NEXT_IP6_LOOKUP] = "ip6-lookup",
    [IP4_MAP_REASS_NEXT_IP4_FRAGMENT] = "ip4-frag",
    [IP4_MAP_REASS_NEXT_DROP] = "error-drop",
  },
};
/* *INDENT-ON* */

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