/*
 * 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_FRAGMENT,
  IP4_MAP_NEXT_REASS,
  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) >= 64) { // 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_is_fragment(ip)) {
      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 {
	  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
  map_main_t *mm = &map_main;
  u32 adj_index0 = mm->adj6_index;
  if (adj_index0 > 0) {
    ip_lookup_main_t *lm6 = &ip6_main.lookup_main;
    ip_adjacency_t *adj = ip_get_adjacency(lm6, mm->adj6_index);
    if (adj->n_adj > 1) {
      u32 hash_c0 = ip4_compute_flow_hash(ip, IP_FLOW_HASH_DEFAULT);
      adj_index0 += (hash_c0 & (adj->n_adj - 1));
    }
    vnet_buffer(p0)->ip.adj_index[VLIB_TX] = adj_index0;
    return (true);
  }
#endif
  return (false);
}

/*
 * 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);
      p0->current_length = clib_net_to_host_u16(ip40->length);
      p1->current_length = clib_net_to_host_u16(ip41->length);
      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);

      /* 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_UNKNOWN;
      if (dal61 == 0 && dar61 == 0) error1 = MAP_ERROR_UNKNOWN;

      /* 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))) {
	  vnet_buffer(p0)->ip_frag.header_offset = sizeof(*ip6h0);
	  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_NEXT_FRAGMENT;
	} 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))) {
	  vnet_buffer(p1)->ip_frag.header_offset = sizeof(*ip6h1);
	  vnet_buffer(p1)->ip_frag.next_index = IP4_FRAG_NEXT_IP6_LOOKUP;
	  vnet_buffer(p1)->ip_frag.mtu = d1->mtu;
	  vnet_buffer(p1)->ip_frag.flags = IP_FRAG_FLAG_IP6_HEADER;
	  next1 = IP4_MAP_NEXT_FRAGMENT;
	} 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);
      p0->current_length = clib_net_to_host_u16(ip40->length);
      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);

      /* 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) error0 = MAP_ERROR_UNKNOWN;

      /* 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))) {
	  vnet_buffer(p0)->ip_frag.header_offset = sizeof(*ip6h0);
	  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_NEXT_FRAGMENT;
	} 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) {
          memcpy(from, fragments_to_loopback, sizeof(u32)*len);
          n_left_from = len;
          vec_reset_length(fragments_to_loopback);
        } else {
          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 _
};

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-rewrite",
#endif
    [IP4_MAP_NEXT_FRAGMENT] = "ip4-frag",
    [IP4_MAP_NEXT_REASS] = "ip4-map-reass",
    [IP4_MAP_NEXT_DROP] = "error-drop",
  },
};

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",
  },
};