ip6_forward.c

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/*
 * Copyright (c) 2016 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.
 */
/*
 * ip/ip6_forward.c: IP v6 forwarding
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <vnet/vnet.h>
#include <vnet/ip/ip.h>
#include <vnet/ethernet/ethernet.h> /* for ethernet_header_t */
#include <vnet/srp/srp.h>       /* for srp_hw_interface_class */
#include <vppinfra/cache.h>
#include <vnet/fib/fib_table.h>
#include <vnet/fib/ip6_fib.h>
#include <vnet/dpo/load_balance.h>
#include <vnet/dpo/classify_dpo.h>

#include <vppinfra/bihash_template.c>

/**
 * @file
 * @brief IPv6 Forwarding.
 *
 * This file contains the source code for IPv6 forwarding.
 */

void
ip6_forward_next_trace (vlib_main_t * vm,
                        vlib_node_runtime_t * node,
                        vlib_frame_t * frame,
                        vlib_rx_or_tx_t which_adj_index);

always_inline uword
ip6_lookup_inline (vlib_main_t * vm,
                   vlib_node_runtime_t * node,
                   vlib_frame_t * frame)
{
  ip6_main_t * im = &ip6_main;
  vlib_combined_counter_main_t * cm = &load_balance_main.lbm_to_counters;
  u32 n_left_from, n_left_to_next, * from, * to_next;
  ip_lookup_next_t next;
  u32 cpu_index = os_get_cpu_number();

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

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

      while (n_left_from >= 4 && n_left_to_next >= 2)
        {
          vlib_buffer_t * p0, * p1;
          u32 pi0, pi1, lbi0, lbi1, wrong_next;
          ip_lookup_next_t next0, next1;
          ip6_header_t * ip0, * ip1;
          ip6_address_t * dst_addr0, * dst_addr1;
          u32 fib_index0, fib_index1;
          u32 flow_hash_config0, flow_hash_config1;
          const dpo_id_t *dpo0, *dpo1;
          const load_balance_t *lb0, *lb1;

          /* 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);
            CLIB_PREFETCH (p2->data, sizeof (ip0[0]), LOAD);
            CLIB_PREFETCH (p3->data, sizeof (ip0[0]), LOAD);
          }

          pi0 = to_next[0] = from[0];
          pi1 = to_next[1] = from[1];

          p0 = vlib_get_buffer (vm, pi0);
          p1 = vlib_get_buffer (vm, pi1);

          ip0 = vlib_buffer_get_current (p0);
          ip1 = vlib_buffer_get_current (p1);

          dst_addr0 = &ip0->dst_address;
          dst_addr1 = &ip1->dst_address;

          fib_index0 = vec_elt (im->fib_index_by_sw_if_index, vnet_buffer (p0)->sw_if_index[VLIB_RX]);
          fib_index1 = vec_elt (im->fib_index_by_sw_if_index, vnet_buffer (p1)->sw_if_index[VLIB_RX]);

          fib_index0 = (vnet_buffer(p0)->sw_if_index[VLIB_TX] == (u32)~0) ?
            fib_index0 : vnet_buffer(p0)->sw_if_index[VLIB_TX];
          fib_index1 = (vnet_buffer(p1)->sw_if_index[VLIB_TX] == (u32)~0) ?
            fib_index1 : vnet_buffer(p1)->sw_if_index[VLIB_TX];

          lbi0 = ip6_fib_table_fwding_lookup (im, fib_index0, dst_addr0);
          lbi1 = ip6_fib_table_fwding_lookup (im, fib_index1, dst_addr1);

          lb0 = load_balance_get (lbi0);
          lb1 = load_balance_get (lbi1);

          vnet_buffer (p0)->ip.flow_hash =
            vnet_buffer(p1)->ip.flow_hash = 0;

          if (PREDICT_FALSE(lb0->lb_n_buckets > 1))
            {
              flow_hash_config0 = lb0->lb_hash_config;
              vnet_buffer (p0)->ip.flow_hash =
                ip6_compute_flow_hash (ip0, flow_hash_config0);
            }
          if (PREDICT_FALSE(lb1->lb_n_buckets > 1))
            {
              flow_hash_config1 = lb1->lb_hash_config;
              vnet_buffer (p1)->ip.flow_hash =
                ip6_compute_flow_hash (ip1, flow_hash_config1);
            }

          ASSERT (lb0->lb_n_buckets > 0);
          ASSERT (lb1->lb_n_buckets > 0);
          ASSERT (is_pow2 (lb0->lb_n_buckets));
          ASSERT (is_pow2 (lb1->lb_n_buckets));
          dpo0 = load_balance_get_bucket_i(lb0,
                                           (vnet_buffer (p0)->ip.flow_hash &
                                            lb0->lb_n_buckets_minus_1));
          dpo1 = load_balance_get_bucket_i(lb1,
                                           (vnet_buffer (p1)->ip.flow_hash &
                                            lb1->lb_n_buckets_minus_1));

          next0 = dpo0->dpoi_next_node;
          next1 = dpo1->dpoi_next_node;

          /* Only process the HBH Option Header if explicitly configured to do so */
          if (PREDICT_FALSE(ip0->protocol == IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS))
            {
              next0 = (dpo_is_adj(dpo0) && im->hbh_enabled) ?
                (ip_lookup_next_t) IP6_LOOKUP_NEXT_HOP_BY_HOP : next0;
            }
          if (PREDICT_FALSE(ip1->protocol == IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS))
            {
              next1 = (dpo_is_adj(dpo1) && im->hbh_enabled) ?
                (ip_lookup_next_t) IP6_LOOKUP_NEXT_HOP_BY_HOP : next1;
            }
          vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
          vnet_buffer (p1)->ip.adj_index[VLIB_TX] = dpo1->dpoi_index;

          vlib_increment_combined_counter
              (cm, cpu_index, lbi0, 1,
               vlib_buffer_length_in_chain (vm, p0));
          vlib_increment_combined_counter
              (cm, cpu_index, lbi1, 1,
               vlib_buffer_length_in_chain (vm, p1));

          from += 2;
          to_next += 2;
          n_left_to_next -= 2;
          n_left_from -= 2;

          wrong_next = (next0 != next) + 2*(next1 != next);
          if (PREDICT_FALSE (wrong_next != 0))
            {
              switch (wrong_next)
                {
                case 1:
                  /* A B A */
                  to_next[-2] = pi1;
                  to_next -= 1;
                  n_left_to_next += 1;
                  vlib_set_next_frame_buffer (vm, node, next0, pi0);
                  break;

                case 2:
                  /* A A B */
                  to_next -= 1;
                  n_left_to_next += 1;
                  vlib_set_next_frame_buffer (vm, node, next1, pi1);
                  break;

                case 3:
                  /* A B C */
                  to_next -= 2;
                  n_left_to_next += 2;
                  vlib_set_next_frame_buffer (vm, node, next0, pi0);
                  vlib_set_next_frame_buffer (vm, node, next1, pi1);
                  if (next0 == next1)
                    {
                      /* A B B */
                      vlib_put_next_frame (vm, node, next, n_left_to_next);
                      next = next1;
                      vlib_get_next_frame (vm, node, next, to_next, n_left_to_next);
                    }
                }
            }
        }

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          vlib_buffer_t * p0;
          ip6_header_t * ip0;
          u32 pi0, lbi0;
          ip_lookup_next_t next0;
          load_balance_t * lb0;
          ip6_address_t * dst_addr0;
          u32 fib_index0, flow_hash_config0;
          const dpo_id_t *dpo0;

          pi0 = from[0];
          to_next[0] = pi0;

          p0 = vlib_get_buffer (vm, pi0);

          ip0 = vlib_buffer_get_current (p0);

          dst_addr0 = &ip0->dst_address;

          fib_index0 = vec_elt (im->fib_index_by_sw_if_index, vnet_buffer (p0)->sw_if_index[VLIB_RX]);
          fib_index0 = (vnet_buffer(p0)->sw_if_index[VLIB_TX] == (u32)~0) ?
            fib_index0 : vnet_buffer(p0)->sw_if_index[VLIB_TX];

          flow_hash_config0 =
              ip6_fib_get (fib_index0)->flow_hash_config;

          lbi0 = ip6_fib_table_fwding_lookup (im, fib_index0, dst_addr0);

          lb0 = load_balance_get (lbi0);

          vnet_buffer (p0)->ip.flow_hash = 0;

          if (PREDICT_FALSE(lb0->lb_n_buckets > 1))
            {
              flow_hash_config0 = lb0->lb_hash_config;
              vnet_buffer (p0)->ip.flow_hash =
                ip6_compute_flow_hash (ip0, flow_hash_config0);
            }

          ASSERT (lb0->lb_n_buckets > 0);
          ASSERT (is_pow2 (lb0->lb_n_buckets));
          dpo0 = load_balance_get_bucket_i(lb0,
                                           (vnet_buffer (p0)->ip.flow_hash &
                                            lb0->lb_n_buckets_minus_1));
          next0 = dpo0->dpoi_next_node;

          /* Only process the HBH Option Header if explicitly configured to do so */
          if (PREDICT_FALSE(ip0->protocol == IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS))
            {
              next0 = (dpo_is_adj(dpo0) && im->hbh_enabled) ?
                (ip_lookup_next_t) IP6_LOOKUP_NEXT_HOP_BY_HOP : next0;
            }
          vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;

          vlib_increment_combined_counter
              (cm, cpu_index, lbi0, 1,
               vlib_buffer_length_in_chain (vm, p0));

          from += 1;
          to_next += 1;
          n_left_to_next -= 1;
          n_left_from -= 1;

          if (PREDICT_FALSE (next0 != next))
            {
              n_left_to_next += 1;
              vlib_put_next_frame (vm, node, next, n_left_to_next);
              next = next0;
              vlib_get_next_frame (vm, node, next,
                                   to_next, n_left_to_next);
              to_next[0] = pi0;
              to_next += 1;
              n_left_to_next -= 1;
            }
        }

      vlib_put_next_frame (vm, node, next, n_left_to_next);
    }

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    ip6_forward_next_trace(vm, node, frame, VLIB_TX);

  return frame->n_vectors;
}

static void
ip6_add_interface_routes (vnet_main_t * vnm, u32 sw_if_index,
                          ip6_main_t * im, u32 fib_index,
                          ip_interface_address_t * a)
{
  ip_lookup_main_t * lm = &im->lookup_main;
  ip6_address_t * address = ip_interface_address_get_address (lm, a);
  fib_prefix_t pfx = {
      .fp_len = a->address_length,
      .fp_proto = FIB_PROTOCOL_IP6,
      .fp_addr.ip6 = *address,
  };

  a->neighbor_probe_adj_index = ~0;
  if (a->address_length < 128)
  {
      fib_node_index_t fei;

      fei = fib_table_entry_update_one_path(fib_index,
                                            &pfx,
                                            FIB_SOURCE_INTERFACE,
                                            (FIB_ENTRY_FLAG_CONNECTED |
                                             FIB_ENTRY_FLAG_ATTACHED),
                                            FIB_PROTOCOL_IP6,
                                            NULL, /* No next-hop address */
                                            sw_if_index,
                                            ~0, // invalid FIB index
                                            1,
                                            MPLS_LABEL_INVALID,
                                            FIB_ROUTE_PATH_FLAG_NONE);
      a->neighbor_probe_adj_index = fib_entry_get_adj(fei);
  }

  pfx.fp_len = 128;
  if (sw_if_index < vec_len (lm->classify_table_index_by_sw_if_index))
  {
      u32 classify_table_index =
          lm->classify_table_index_by_sw_if_index [sw_if_index];
      if (classify_table_index != (u32) ~0)
      {
          dpo_id_t dpo = DPO_INVALID;

          dpo_set(&dpo,
                  DPO_CLASSIFY,
                  DPO_PROTO_IP6,
                  classify_dpo_create(DPO_PROTO_IP6, classify_table_index));

          fib_table_entry_special_dpo_add(fib_index,
                                          &pfx,
                                          FIB_SOURCE_CLASSIFY,
                                          FIB_ENTRY_FLAG_NONE,
                                          &dpo);
          dpo_reset(&dpo);
      }
  }

  fib_table_entry_update_one_path(fib_index,
                                  &pfx,
                                  FIB_SOURCE_INTERFACE,
                                  (FIB_ENTRY_FLAG_CONNECTED |
                                   FIB_ENTRY_FLAG_LOCAL),
                                  FIB_PROTOCOL_IP6,
                                  &pfx.fp_addr,
                                  sw_if_index,
                                  ~0, // invalid FIB index
                                  1,
                                  MPLS_LABEL_INVALID,
                                  FIB_ROUTE_PATH_FLAG_NONE);
}

static void
ip6_del_interface_routes (ip6_main_t * im,
                          u32 fib_index,
                          ip6_address_t * address,
                          u32 address_length)
{
    fib_prefix_t pfx = {
        .fp_len = address_length,
        .fp_proto = FIB_PROTOCOL_IP6,
        .fp_addr.ip6 = *address,
    };

    if (pfx.fp_len < 128)
    {
        fib_table_entry_delete(fib_index,
                               &pfx,
                               FIB_SOURCE_INTERFACE);

    }

    pfx.fp_len = 128;
    fib_table_entry_delete(fib_index,
                           &pfx,
                           FIB_SOURCE_INTERFACE);
}

void
ip6_sw_interface_enable_disable (u32 sw_if_index,
                                 u32 is_enable)
{
  vlib_main_t * vm = vlib_get_main();
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t * lm = &im->lookup_main;
  u32 ci, cast;
  u32 lookup_feature_index;

  vec_validate_init_empty (im->ip_enabled_by_sw_if_index, sw_if_index, 0);

  /*
   * enable/disable only on the 1<->0 transition
   */
  if (is_enable)
    {
      if (1 != ++im->ip_enabled_by_sw_if_index[sw_if_index])
        return;
    }
  else
    {
      ASSERT(im->ip_enabled_by_sw_if_index[sw_if_index] > 0);
      if (0 != --im->ip_enabled_by_sw_if_index[sw_if_index])
        return;
    }

  for (cast = 0; cast <= VNET_IP_RX_MULTICAST_FEAT; cast++)
    {
      vnet_feature_config_main_t * cm = &lm->feature_config_mains[cast];
      vnet_config_main_t * vcm = &cm->config_main;

      vec_validate_init_empty (cm->config_index_by_sw_if_index, sw_if_index, ~0);
      ci = cm->config_index_by_sw_if_index[sw_if_index];

      if (cast == VNET_IP_RX_UNICAST_FEAT)
        lookup_feature_index = im->ip6_unicast_rx_feature_lookup;
      else
        lookup_feature_index = im->ip6_multicast_rx_feature_lookup;

      if (is_enable)
        ci = vnet_config_add_feature (vm, vcm,
                                      ci,
                                      lookup_feature_index,
                                      /* config data */ 0,
                                      /* # bytes of config data */ 0);
      else
        ci = vnet_config_del_feature (vm, vcm,
                                      ci,
                                      lookup_feature_index,
                                      /* config data */ 0,
                                      /* # bytes of config data */ 0);

      cm->config_index_by_sw_if_index[sw_if_index] = ci;
    }
}

/* get first interface address */
ip6_address_t *
ip6_interface_first_address (ip6_main_t * im,
                             u32 sw_if_index,
                             ip_interface_address_t ** result_ia)
{
  ip_lookup_main_t * lm = &im->lookup_main;
  ip_interface_address_t * ia = 0;
  ip6_address_t * result = 0;

  foreach_ip_interface_address (lm, ia, sw_if_index,
                                1 /* honor unnumbered */,
  ({
    ip6_address_t * a = ip_interface_address_get_address (lm, ia);
    result = a;
    break;
  }));
  if (result_ia)
    *result_ia = result ? ia : 0;
  return result;
}

clib_error_t *
ip6_add_del_interface_address (vlib_main_t * vm,
                               u32 sw_if_index,
                               ip6_address_t * address,
                               u32 address_length,
                               u32 is_del)
{
  vnet_main_t * vnm = vnet_get_main();
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t * lm = &im->lookup_main;
  clib_error_t * error;
  u32 if_address_index;
  ip6_address_fib_t ip6_af, * addr_fib = 0;

  vec_validate (im->fib_index_by_sw_if_index, sw_if_index);
  ip6_addr_fib_init (&ip6_af, address,
                     vec_elt (im->fib_index_by_sw_if_index, sw_if_index));
  vec_add1 (addr_fib, ip6_af);

  {
    uword elts_before = pool_elts (lm->if_address_pool);

    error = ip_interface_address_add_del
      (lm,
       sw_if_index,
       addr_fib,
       address_length,
       is_del,
       &if_address_index);
    if (error)
      goto done;

    /* Pool did not grow: add duplicate address. */
    if (elts_before == pool_elts (lm->if_address_pool))
      goto done;
  }

  if (is_del)
      ip6_del_interface_routes (im, ip6_af.fib_index, address,
                                address_length);
  else
      ip6_add_interface_routes (vnm, sw_if_index,
                                im, ip6_af.fib_index,
                                pool_elt_at_index (lm->if_address_pool, if_address_index));

  {
    ip6_add_del_interface_address_callback_t * cb;
    vec_foreach (cb, im->add_del_interface_address_callbacks)
      cb->function (im, cb->function_opaque, sw_if_index,
                    address, address_length,
                    if_address_index,
                    is_del);
  }

 done:
  vec_free (addr_fib);
  return error;
}

clib_error_t *
ip6_sw_interface_admin_up_down (vnet_main_t * vnm,
                                u32 sw_if_index,
                                u32 flags)
{
  ip6_main_t * im = &ip6_main;
  ip_interface_address_t * ia;
  ip6_address_t * a;
  u32 is_admin_up, fib_index;

  /* Fill in lookup tables with default table (0). */
  vec_validate (im->fib_index_by_sw_if_index, sw_if_index);

  vec_validate_init_empty (im->lookup_main.if_address_pool_index_by_sw_if_index, sw_if_index, ~0);

  is_admin_up = (flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) != 0;

  fib_index = vec_elt (im->fib_index_by_sw_if_index, sw_if_index);

  foreach_ip_interface_address (&im->lookup_main, ia, sw_if_index,
                                0 /* honor unnumbered */,
  ({
    a = ip_interface_address_get_address (&im->lookup_main, ia);
    if (is_admin_up)
      ip6_add_interface_routes (vnm, sw_if_index,
                                im, fib_index,
                                ia);
    else
      ip6_del_interface_routes (im, fib_index,
                                a, ia->address_length);
  }));

  return 0;
}

VNET_SW_INTERFACE_ADMIN_UP_DOWN_FUNCTION (ip6_sw_interface_admin_up_down);

/* Built-in ip6 unicast rx feature path definition */
VNET_IP6_UNICAST_FEATURE_INIT (ip6_flow_classify, static) = {
  .node_name = "ip6-flow-classify",
  .runs_before = ORDER_CONSTRAINTS {"ip6-inacl", 0},
  .feature_index = &ip6_main.ip6_unicast_rx_feature_flow_classify,
};

VNET_IP6_UNICAST_FEATURE_INIT (ip6_inacl, static) = {
  .node_name = "ip6-inacl",
  .runs_before = ORDER_CONSTRAINTS {"ip6-policer-classify", 0},
  .feature_index = &ip6_main.ip6_unicast_rx_feature_check_access,
};

VNET_IP6_UNICAST_FEATURE_INIT (ip6_policer_classify, static) = {
  .node_name = "ip6-policer-classify",
  .runs_before = ORDER_CONSTRAINTS {"ipsec-input-ip6", 0},
  .feature_index = &ip6_main.ip6_unicast_rx_feature_policer_classify,
};

VNET_IP6_UNICAST_FEATURE_INIT (ip6_ipsec, static) = {
  .node_name = "ipsec-input-ip6",
  .runs_before = ORDER_CONSTRAINTS {"l2tp-decap", 0},
  .feature_index = &ip6_main.ip6_unicast_rx_feature_ipsec,
};

VNET_IP6_UNICAST_FEATURE_INIT (ip6_l2tp, static) = {
  .node_name = "l2tp-decap",
  .runs_before = ORDER_CONSTRAINTS {"vpath-input-ip6", 0},
  .feature_index = &ip6_main.ip6_unicast_rx_feature_l2tp_decap,
};

VNET_IP6_UNICAST_FEATURE_INIT (ip6_vpath, static) = {
  .node_name = "vpath-input-ip6",
  .runs_before = ORDER_CONSTRAINTS {"ip6-lookup", 0},
  .feature_index = &ip6_main.ip6_unicast_rx_feature_vpath,
};

VNET_IP6_UNICAST_FEATURE_INIT (ip6_lookup, static) = {
  .node_name = "ip6-lookup",
  .runs_before = ORDER_CONSTRAINTS {"ip6-drop", 0},
  .feature_index = &ip6_main.ip6_unicast_rx_feature_lookup,
};

VNET_IP6_UNICAST_FEATURE_INIT (ip6_drop, static) = {
  .node_name = "ip6-drop",
  .runs_before = 0,  /*last feature*/
  .feature_index = &ip6_main.ip6_unicast_rx_feature_drop,
};

/* Built-in ip6 multicast rx feature path definition (none now) */
VNET_IP6_MULTICAST_FEATURE_INIT (ip6_vpath_mc, static) = {
  .node_name = "vpath-input-ip6",
  .runs_before = ORDER_CONSTRAINTS {"ip6-lookup", 0},
  .feature_index = &ip6_main.ip6_multicast_rx_feature_vpath,
};

VNET_IP6_MULTICAST_FEATURE_INIT (ip6_lookup, static) = {
  .node_name = "ip6-lookup",
  .runs_before = ORDER_CONSTRAINTS {"ip6-drop", 0},
  .feature_index = &ip6_main.ip6_multicast_rx_feature_lookup,
};

VNET_IP6_MULTICAST_FEATURE_INIT (ip6_drop_mc, static) = {
  .node_name = "ip6-drop",
  .runs_before = 0, /* last feature */
  .feature_index = &ip6_main.ip6_multicast_rx_feature_drop,
};

static char * rx_feature_start_nodes[] =
  {"ip6-input"};

static char * tx_feature_start_nodes[] =
{
  "ip6-rewrite",
  "ip6-midchain",
};

/* Built-in ip4 tx feature path definition */
VNET_IP6_TX_FEATURE_INIT (interface_output, static) = {
  .node_name = "interface-output",
  .runs_before = 0, /* not before any other features */
  .feature_index = &ip6_main.ip6_tx_feature_interface_output,
};

static clib_error_t *
ip6_feature_init (vlib_main_t * vm, ip6_main_t * im)
{
  ip_lookup_main_t * lm = &im->lookup_main;
  clib_error_t * error;
  vnet_cast_t cast;
  vnet_feature_config_main_t * cm;
  vnet_config_main_t * vcm;
  char **feature_start_nodes;
  int feature_start_len;

  for (cast = 0; cast < VNET_N_IP_FEAT; cast++)
    {
      cm = &lm->feature_config_mains[cast];
      vcm = &cm->config_main;

      if (cast < VNET_IP_TX_FEAT)
        {
          feature_start_nodes = rx_feature_start_nodes;
          feature_start_len = ARRAY_LEN(rx_feature_start_nodes);
        }
      else
        {
          feature_start_nodes = tx_feature_start_nodes;
          feature_start_len = ARRAY_LEN(tx_feature_start_nodes);
        }

      if ((error = vnet_feature_arc_init (vm, vcm,
                                         feature_start_nodes,
                                         feature_start_len,
                                         im->next_feature[cast],
                                         &im->feature_nodes[cast])))
        return error;
    }
  return 0;
}

clib_error_t *
ip6_sw_interface_add_del (vnet_main_t * vnm,
                          u32 sw_if_index,
                          u32 is_add)
{
  vlib_main_t * vm = vnm->vlib_main;
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t * lm = &im->lookup_main;
  u32 ci, cast;
  u32 feature_index;

  for (cast = 0; cast < VNET_N_IP_FEAT; cast++)
    {
      vnet_feature_config_main_t * cm = &lm->feature_config_mains[cast];
      vnet_config_main_t * vcm = &cm->config_main;

      vec_validate_init_empty (cm->config_index_by_sw_if_index, sw_if_index, ~0);
      ci = cm->config_index_by_sw_if_index[sw_if_index];

      if (cast == VNET_IP_RX_UNICAST_FEAT)
        feature_index = im->ip6_unicast_rx_feature_drop;
      else if (cast == VNET_IP_RX_MULTICAST_FEAT)
        feature_index = im->ip6_multicast_rx_feature_drop;
      else
        feature_index = im->ip6_tx_feature_interface_output;

      if (is_add)
        ci = vnet_config_add_feature (vm, vcm,
                                      ci,
                                      feature_index,
                                      /* config data */ 0,
                                      /* # bytes of config data */ 0);
      else
        {
          ci = vnet_config_del_feature (vm, vcm, ci,
                                        feature_index,
                                        /* config data */ 0,
                                        /* # bytes of config data */ 0);
          if (vec_len(im->ip_enabled_by_sw_if_index) > sw_if_index)
              im->ip_enabled_by_sw_if_index[sw_if_index] = 0;
        }
      cm->config_index_by_sw_if_index[sw_if_index] = ci;
      /*
       * note: do not update the tx feature count here.
       */
    }
  return /* no error */ 0;
}

VNET_SW_INTERFACE_ADD_DEL_FUNCTION (ip6_sw_interface_add_del);

static uword
ip6_lookup (vlib_main_t * vm,
            vlib_node_runtime_t * node,
            vlib_frame_t * frame)
{
  return ip6_lookup_inline (vm, node, frame);
}

static u8 * format_ip6_lookup_trace (u8 * s, va_list * args);

VLIB_REGISTER_NODE (ip6_lookup_node) = {
  .function = ip6_lookup,
  .name = "ip6-lookup",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_lookup_trace,

  .n_next_nodes = IP6_LOOKUP_N_NEXT,
  .next_nodes = IP6_LOOKUP_NEXT_NODES,
};

VLIB_NODE_FUNCTION_MULTIARCH (ip6_lookup_node, ip6_lookup)

always_inline uword
ip6_load_balance (vlib_main_t * vm,
                  vlib_node_runtime_t * node,
                  vlib_frame_t * frame)
{
  vlib_combined_counter_main_t * cm = &load_balance_main.lbm_via_counters;
  u32 n_left_from, n_left_to_next, * from, * to_next;
  ip_lookup_next_t next;
  u32 cpu_index = os_get_cpu_number();
  ip6_main_t * im = &ip6_main;

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

  if (node->flags & VLIB_NODE_FLAG_TRACE)
      ip6_forward_next_trace(vm, node, frame, VLIB_TX);

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


      while (n_left_from > 0 && n_left_to_next > 0)
        {
          ip_lookup_next_t next0;
          const load_balance_t *lb0;
          vlib_buffer_t * p0;
          u32 pi0, lbi0, hc0;
          const ip6_header_t *ip0;
          const dpo_id_t *dpo0;

          pi0 = from[0];
          to_next[0] = pi0;

          p0 = vlib_get_buffer (vm, pi0);

          ip0 = vlib_buffer_get_current (p0);
          lbi0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];

          lb0 = load_balance_get(lbi0);
          hc0 = lb0->lb_hash_config;
          vnet_buffer(p0)->ip.flow_hash = ip6_compute_flow_hash(ip0, hc0);

          dpo0 = load_balance_get_bucket_i(lb0,
                                           vnet_buffer(p0)->ip.flow_hash &
                                           (lb0->lb_n_buckets - 1));
          next0 = dpo0->dpoi_next_node;
          /* Only process the HBH Option Header if explicitly configured to do so */
          if (PREDICT_FALSE(ip0->protocol == IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS))
            {
              next0 = (dpo_is_adj(dpo0) && im->hbh_enabled) ?
                (ip_lookup_next_t) IP6_LOOKUP_NEXT_HOP_BY_HOP : next0;
            }
          vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;

          vlib_increment_combined_counter
              (cm, cpu_index, lbi0, 1,
               vlib_buffer_length_in_chain (vm, p0));

          from += 1;
          to_next += 1;
          n_left_to_next -= 1;
          n_left_from -= 1;

          if (PREDICT_FALSE (next0 != next))
            {
              n_left_to_next += 1;
              vlib_put_next_frame (vm, node, next, n_left_to_next);
              next = next0;
              vlib_get_next_frame (vm, node, next,
                                   to_next, n_left_to_next);
              to_next[0] = pi0;
              to_next += 1;
              n_left_to_next -= 1;
            }
        }

      vlib_put_next_frame (vm, node, next, n_left_to_next);
    }

  return frame->n_vectors;
}

VLIB_REGISTER_NODE (ip6_load_balance_node) = {
  .function = ip6_load_balance,
  .name = "ip6-load-balance",
  .vector_size = sizeof (u32),
  .sibling_of = "ip6-lookup",
  .format_trace = format_ip6_lookup_trace,
  .n_next_nodes = 0,
};

VLIB_NODE_FUNCTION_MULTIARCH (ip6_load_balance_node, ip6_load_balance)

typedef struct {
  /* Adjacency taken. */
  u32 adj_index;
  u32 flow_hash;
  u32 fib_index;

  /* Packet data, possibly *after* rewrite. */
  u8 packet_data[128 - 1*sizeof(u32)];
} ip6_forward_next_trace_t;

static u8 * format_ip6_forward_next_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 *);
  ip6_forward_next_trace_t * t = va_arg (*args, ip6_forward_next_trace_t *);
  uword indent = format_get_indent (s);

  s = format(s, "%U%U",
             format_white_space, indent,
             format_ip6_header, t->packet_data, sizeof (t->packet_data));
  return s;
}

static u8 * format_ip6_lookup_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 *);
  ip6_forward_next_trace_t * t = va_arg (*args, ip6_forward_next_trace_t *);
  uword indent = format_get_indent (s);

  s = format (s, "fib %d dpo-idx %d flow hash: 0x%08x",
              t->fib_index, t->adj_index, t->flow_hash);
  s = format(s, "\n%U%U",
             format_white_space, indent,
             format_ip6_header, t->packet_data, sizeof (t->packet_data));
  return s;
}


static u8 * format_ip6_rewrite_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 *);
  ip6_forward_next_trace_t * t = va_arg (*args, ip6_forward_next_trace_t *);
  vnet_main_t * vnm = vnet_get_main();
  uword indent = format_get_indent (s);

  s = format (s, "tx_sw_if_index %d adj-idx %d : %U flow hash: 0x%08x",
              t->fib_index, t->adj_index, format_ip_adjacency,
              t->adj_index, FORMAT_IP_ADJACENCY_NONE,
              t->flow_hash);
  s = format (s, "\n%U%U",
              format_white_space, indent,
              format_ip_adjacency_packet_data,
              vnm, t->adj_index,
              t->packet_data, sizeof (t->packet_data));
  return s;
}

/* Common trace function for all ip6-forward next nodes. */
void
ip6_forward_next_trace (vlib_main_t * vm,
                        vlib_node_runtime_t * node,
                        vlib_frame_t * frame,
                        vlib_rx_or_tx_t which_adj_index)
{
  u32 * from, n_left;
  ip6_main_t * im = &ip6_main;

  n_left = frame->n_vectors;
  from = vlib_frame_vector_args (frame);

  while (n_left >= 4)
    {
      u32 bi0, bi1;
      vlib_buffer_t * b0, * b1;
      ip6_forward_next_trace_t * t0, * t1;

      /* Prefetch next iteration. */
      vlib_prefetch_buffer_with_index (vm, from[2], LOAD);
      vlib_prefetch_buffer_with_index (vm, from[3], LOAD);

      bi0 = from[0];
      bi1 = from[1];

      b0 = vlib_get_buffer (vm, bi0);
      b1 = vlib_get_buffer (vm, bi1);

      if (b0->flags & VLIB_BUFFER_IS_TRACED)
        {
          t0 = vlib_add_trace (vm, node, b0, sizeof (t0[0]));
          t0->adj_index = vnet_buffer (b0)->ip.adj_index[which_adj_index];
          t0->flow_hash = vnet_buffer (b0)->ip.flow_hash;
          t0->fib_index = (vnet_buffer(b0)->sw_if_index[VLIB_TX] != (u32)~0) ?
              vnet_buffer(b0)->sw_if_index[VLIB_TX] :
              vec_elt (im->fib_index_by_sw_if_index,
                       vnet_buffer(b0)->sw_if_index[VLIB_RX]);

          clib_memcpy (t0->packet_data,
                  vlib_buffer_get_current (b0),
                  sizeof (t0->packet_data));
        }
      if (b1->flags & VLIB_BUFFER_IS_TRACED)
        {
          t1 = vlib_add_trace (vm, node, b1, sizeof (t1[0]));
          t1->adj_index = vnet_buffer (b1)->ip.adj_index[which_adj_index];
          t1->flow_hash = vnet_buffer (b1)->ip.flow_hash;
          t1->fib_index = (vnet_buffer(b1)->sw_if_index[VLIB_TX] != (u32)~0) ?
              vnet_buffer(b1)->sw_if_index[VLIB_TX] :
              vec_elt (im->fib_index_by_sw_if_index,
                       vnet_buffer(b1)->sw_if_index[VLIB_RX]);

          clib_memcpy (t1->packet_data,
                  vlib_buffer_get_current (b1),
                  sizeof (t1->packet_data));
        }
      from += 2;
      n_left -= 2;
    }

  while (n_left >= 1)
    {
      u32 bi0;
      vlib_buffer_t * b0;
      ip6_forward_next_trace_t * t0;

      bi0 = from[0];

      b0 = vlib_get_buffer (vm, bi0);

      if (b0->flags & VLIB_BUFFER_IS_TRACED)
        {
          t0 = vlib_add_trace (vm, node, b0, sizeof (t0[0]));
          t0->adj_index = vnet_buffer (b0)->ip.adj_index[which_adj_index];
          t0->flow_hash = vnet_buffer (b0)->ip.flow_hash;
          t0->fib_index = (vnet_buffer(b0)->sw_if_index[VLIB_TX] != (u32)~0) ?
              vnet_buffer(b0)->sw_if_index[VLIB_TX] :
              vec_elt (im->fib_index_by_sw_if_index,
                       vnet_buffer(b0)->sw_if_index[VLIB_RX]);

          clib_memcpy (t0->packet_data,
                  vlib_buffer_get_current (b0),
                  sizeof (t0->packet_data));
        }
      from += 1;
      n_left -= 1;
    }
}

static uword
ip6_drop_or_punt (vlib_main_t * vm,
                  vlib_node_runtime_t * node,
                  vlib_frame_t * frame,
                  ip6_error_t error_code)
{
  u32 * buffers = vlib_frame_vector_args (frame);
  uword n_packets = frame->n_vectors;

  vlib_error_drop_buffers (vm, node,
                           buffers,
                           /* stride */ 1,
                           n_packets,
                           /* next */ 0,
                           ip6_input_node.index,
                           error_code);

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    ip6_forward_next_trace (vm, node, frame, VLIB_TX);

  return n_packets;
}

static uword
ip6_drop (vlib_main_t * vm,
          vlib_node_runtime_t * node,
          vlib_frame_t * frame)
{ return ip6_drop_or_punt (vm, node, frame, IP6_ERROR_ADJACENCY_DROP); }

static uword
ip6_punt (vlib_main_t * vm,
          vlib_node_runtime_t * node,
          vlib_frame_t * frame)
{ return ip6_drop_or_punt (vm, node, frame, IP6_ERROR_ADJACENCY_PUNT); }

VLIB_REGISTER_NODE (ip6_drop_node,static) = {
  .function = ip6_drop,
  .name = "ip6-drop",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_forward_next_trace,

  .n_next_nodes = 1,
  .next_nodes = {
    [0] = "error-drop",
  },
};

VLIB_NODE_FUNCTION_MULTIARCH (ip6_drop_node, ip6_drop)

VLIB_REGISTER_NODE (ip6_punt_node,static) = {
  .function = ip6_punt,
  .name = "ip6-punt",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_forward_next_trace,

  .n_next_nodes = 1,
  .next_nodes = {
    [0] = "error-punt",
  },
};

VLIB_NODE_FUNCTION_MULTIARCH (ip6_punt_node, ip6_punt)

VLIB_REGISTER_NODE (ip6_multicast_node,static) = {
  .function = ip6_drop,
  .name = "ip6-multicast",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_forward_next_trace,

  .n_next_nodes = 1,
  .next_nodes = {
    [0] = "error-drop",
  },
};

/* Compute TCP/UDP/ICMP6 checksum in software. */
u16 ip6_tcp_udp_icmp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0, ip6_header_t * ip0, int *bogus_lengthp)
{
  ip_csum_t sum0;
  u16 sum16, payload_length_host_byte_order;
  u32 i, n_this_buffer, n_bytes_left;
  u32 headers_size = sizeof(ip0[0]);
  void * data_this_buffer;

  ASSERT(bogus_lengthp);
  *bogus_lengthp = 0;

  /* Initialize checksum with ip header. */
  sum0 = ip0->payload_length + clib_host_to_net_u16 (ip0->protocol);
  payload_length_host_byte_order = clib_net_to_host_u16 (ip0->payload_length);
  data_this_buffer = (void *) (ip0 + 1);

  for (i = 0; i < ARRAY_LEN (ip0->src_address.as_uword); i++)
    {
      sum0 = ip_csum_with_carry (sum0,
                                 clib_mem_unaligned (&ip0->src_address.as_uword[i], uword));
      sum0 = ip_csum_with_carry (sum0,
                                 clib_mem_unaligned (&ip0->dst_address.as_uword[i], uword));
    }

  /* some icmp packets may come with a "router alert" hop-by-hop extension header (e.g., mldv2 packets) */
  if (PREDICT_FALSE (ip0->protocol ==  IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS))
    {
      u32  skip_bytes;
      ip6_hop_by_hop_ext_t *ext_hdr = (ip6_hop_by_hop_ext_t  *)data_this_buffer;

      /* validate really icmp6 next */
      ASSERT(ext_hdr->next_hdr == IP_PROTOCOL_ICMP6);

      skip_bytes = 8* (1 + ext_hdr->n_data_u64s);
      data_this_buffer  = (void *)((u8 *)data_this_buffer + skip_bytes);

      payload_length_host_byte_order  -= skip_bytes;
      headers_size += skip_bytes;
   }

  n_bytes_left = n_this_buffer = payload_length_host_byte_order;
#if DPDK > 0
  if (p0 && n_this_buffer + headers_size  > p0->current_length)
  {
    struct rte_mbuf *mb = rte_mbuf_from_vlib_buffer(p0);
    u8 nb_segs = mb->nb_segs;

    n_this_buffer = (p0->current_length > headers_size ?
                     p0->current_length - headers_size : 0);
    while (n_bytes_left)
      {
        sum0 = ip_incremental_checksum (sum0, data_this_buffer, n_this_buffer);
        n_bytes_left -= n_this_buffer;

        mb = mb->next;
        nb_segs--;
        if ((nb_segs == 0) || (mb == 0))
          break;

        data_this_buffer = rte_ctrlmbuf_data(mb);
        n_this_buffer = mb->data_len;
      }
    if (n_bytes_left || nb_segs)
      {
        *bogus_lengthp = 1;
        return 0xfefe;
      }
  }
  else sum0 = ip_incremental_checksum (sum0, data_this_buffer, n_this_buffer);
#else
  if (p0 && n_this_buffer + headers_size  > p0->current_length)
    n_this_buffer = p0->current_length > headers_size  ? p0->current_length - headers_size  : 0;
  while (1)
    {
      sum0 = ip_incremental_checksum (sum0, data_this_buffer, n_this_buffer);
      n_bytes_left -= n_this_buffer;
      if (n_bytes_left == 0)
        break;

      if (!(p0->flags & VLIB_BUFFER_NEXT_PRESENT))
        {
          *bogus_lengthp = 1;
          return 0xfefe;
        }
      p0 = vlib_get_buffer (vm, p0->next_buffer);
      data_this_buffer = vlib_buffer_get_current (p0);
      n_this_buffer = p0->current_length;
    }
#endif /* DPDK */

  sum16 = ~ ip_csum_fold (sum0);

  return sum16;
}

u32 ip6_tcp_udp_icmp_validate_checksum (vlib_main_t * vm, vlib_buffer_t * p0)
{
  ip6_header_t * ip0 = vlib_buffer_get_current (p0);
  udp_header_t * udp0;
  u16 sum16;
  int bogus_length;

  /* some icmp packets may come with a "router alert" hop-by-hop extension header (e.g., mldv2 packets) */
  ASSERT (ip0->protocol == IP_PROTOCOL_TCP
          || ip0->protocol == IP_PROTOCOL_ICMP6
          || ip0->protocol == IP_PROTOCOL_UDP
          || ip0->protocol ==  IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS);

  udp0 = (void *) (ip0 + 1);
  if (ip0->protocol == IP_PROTOCOL_UDP && udp0->checksum == 0)
    {
      p0->flags |= (IP_BUFFER_L4_CHECKSUM_COMPUTED
                    | IP_BUFFER_L4_CHECKSUM_CORRECT);
      return p0->flags;
    }

  sum16 = ip6_tcp_udp_icmp_compute_checksum (vm, p0, ip0, &bogus_length);

  p0->flags |= (IP_BUFFER_L4_CHECKSUM_COMPUTED
                | ((sum16 == 0) << LOG2_IP_BUFFER_L4_CHECKSUM_CORRECT));

  return p0->flags;
}

static uword
ip6_local (vlib_main_t * vm,
           vlib_node_runtime_t * node,
           vlib_frame_t * frame)
{
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t * lm = &im->lookup_main;
  ip_local_next_t next_index;
  u32 * from, * to_next, n_left_from, n_left_to_next;
  vlib_node_runtime_t * error_node = vlib_node_get_runtime (vm, ip6_input_node.index);

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

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    ip6_forward_next_trace (vm, node, frame, VLIB_TX);

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

      while (n_left_from >= 4 && n_left_to_next >= 2)
        {
          vlib_buffer_t * p0, * p1;
          ip6_header_t * ip0, * ip1;
          udp_header_t * udp0, * udp1;
          u32 pi0, ip_len0, udp_len0, flags0, next0;
          u32 pi1, ip_len1, udp_len1, flags1, next1;
          i32 len_diff0, len_diff1;
          u8 error0, type0, good_l4_checksum0;
          u8 error1, type1, good_l4_checksum1;

          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);

          ip0 = vlib_buffer_get_current (p0);
          ip1 = vlib_buffer_get_current (p1);

          type0 = lm->builtin_protocol_by_ip_protocol[ip0->protocol];
          type1 = lm->builtin_protocol_by_ip_protocol[ip1->protocol];

          next0 = lm->local_next_by_ip_protocol[ip0->protocol];
          next1 = lm->local_next_by_ip_protocol[ip1->protocol];

          flags0 = p0->flags;
          flags1 = p1->flags;

          good_l4_checksum0 = (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
          good_l4_checksum1 = (flags1 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;

          udp0 = ip6_next_header (ip0);
          udp1 = ip6_next_header (ip1);

          /* Don't verify UDP checksum for packets with explicit zero checksum. */
          good_l4_checksum0 |= type0 == IP_BUILTIN_PROTOCOL_UDP && udp0->checksum == 0;
          good_l4_checksum1 |= type1 == IP_BUILTIN_PROTOCOL_UDP && udp1->checksum == 0;

          good_l4_checksum0 |= type0 == IP_BUILTIN_PROTOCOL_UNKNOWN;
          good_l4_checksum1 |= type1 == IP_BUILTIN_PROTOCOL_UNKNOWN;

          /* Verify UDP length. */
          ip_len0 = clib_net_to_host_u16 (ip0->payload_length);
          ip_len1 = clib_net_to_host_u16 (ip1->payload_length);
          udp_len0 = clib_net_to_host_u16 (udp0->length);
          udp_len1 = clib_net_to_host_u16 (udp1->length);

          len_diff0 = ip_len0 - udp_len0;
          len_diff1 = ip_len1 - udp_len1;

          len_diff0 = type0 == IP_BUILTIN_PROTOCOL_UDP ? len_diff0 : 0;
          len_diff1 = type1 == IP_BUILTIN_PROTOCOL_UDP ? len_diff1 : 0;

          if (PREDICT_FALSE (type0 != IP_BUILTIN_PROTOCOL_UNKNOWN
                             && ! good_l4_checksum0
                             && ! (flags0 & IP_BUFFER_L4_CHECKSUM_COMPUTED)))
            {
              flags0 = ip6_tcp_udp_icmp_validate_checksum (vm, p0);
              good_l4_checksum0 =
                (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
            }
          if (PREDICT_FALSE (type1 != IP_BUILTIN_PROTOCOL_UNKNOWN
                             && ! good_l4_checksum1
                             && ! (flags1 & IP_BUFFER_L4_CHECKSUM_COMPUTED)))
            {
              flags1 = ip6_tcp_udp_icmp_validate_checksum (vm, p1);
              good_l4_checksum1 =
                (flags1 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
            }

          error0 = error1 = IP6_ERROR_UNKNOWN_PROTOCOL;

          error0 = len_diff0 < 0 ? IP6_ERROR_UDP_LENGTH : error0;
          error1 = len_diff1 < 0 ? IP6_ERROR_UDP_LENGTH : error1;

          ASSERT (IP6_ERROR_UDP_CHECKSUM + IP_BUILTIN_PROTOCOL_UDP == IP6_ERROR_UDP_CHECKSUM);
          ASSERT (IP6_ERROR_UDP_CHECKSUM + IP_BUILTIN_PROTOCOL_ICMP == IP6_ERROR_ICMP_CHECKSUM);
          error0 = (! good_l4_checksum0
                    ? IP6_ERROR_UDP_CHECKSUM + type0
                    : error0);
          error1 = (! good_l4_checksum1
                    ? IP6_ERROR_UDP_CHECKSUM + type1
                    : error1);

          /* Drop packets from unroutable hosts. */
          /* If this is a neighbor solicitation (ICMP), skip source RPF check */
          if (error0 == IP6_ERROR_UNKNOWN_PROTOCOL &&
              type0 != IP_BUILTIN_PROTOCOL_ICMP &&
              !ip6_address_is_link_local_unicast(&ip0->src_address))
            {
              u32 src_adj_index0 = ip6_src_lookup_for_packet (im, p0, ip0);
              error0 = (ADJ_INDEX_INVALID == src_adj_index0
                        ? IP6_ERROR_SRC_LOOKUP_MISS
                        : error0);
            }
          if (error1 == IP6_ERROR_UNKNOWN_PROTOCOL &&
              type1 != IP_BUILTIN_PROTOCOL_ICMP &&
              !ip6_address_is_link_local_unicast(&ip1->src_address))
            {
              u32 src_adj_index1 = ip6_src_lookup_for_packet (im, p1, ip1);
              error1 = (ADJ_INDEX_INVALID == src_adj_index1
                        ? IP6_ERROR_SRC_LOOKUP_MISS
                        : error1);
            }

          next0 = error0 != IP6_ERROR_UNKNOWN_PROTOCOL ? IP_LOCAL_NEXT_DROP : next0;
          next1 = error1 != IP6_ERROR_UNKNOWN_PROTOCOL ? IP_LOCAL_NEXT_DROP : next1;

          p0->error = error_node->errors[error0];
          p1->error = error_node->errors[error1];

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

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          vlib_buffer_t * p0;
          ip6_header_t * ip0;
          udp_header_t * udp0;
          u32 pi0, ip_len0, udp_len0, flags0, next0;
          i32 len_diff0;
          u8 error0, type0, good_l4_checksum0;

          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);

          ip0 = vlib_buffer_get_current (p0);

          type0 = lm->builtin_protocol_by_ip_protocol[ip0->protocol];
          next0 = lm->local_next_by_ip_protocol[ip0->protocol];

          flags0 = p0->flags;

          good_l4_checksum0 = (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;

          udp0 = ip6_next_header (ip0);

          /* Don't verify UDP checksum for packets with explicit zero checksum. */
          good_l4_checksum0 |= type0 == IP_BUILTIN_PROTOCOL_UDP && udp0->checksum == 0;

          good_l4_checksum0 |= type0 == IP_BUILTIN_PROTOCOL_UNKNOWN;

          /* Verify UDP length. */
          ip_len0 = clib_net_to_host_u16 (ip0->payload_length);
          udp_len0 = clib_net_to_host_u16 (udp0->length);

          len_diff0 = ip_len0 - udp_len0;

          len_diff0 = type0 == IP_BUILTIN_PROTOCOL_UDP ? len_diff0 : 0;

          if (PREDICT_FALSE (type0 != IP_BUILTIN_PROTOCOL_UNKNOWN
                             && ! good_l4_checksum0
                             && ! (flags0 & IP_BUFFER_L4_CHECKSUM_COMPUTED)))
            {
              flags0 = ip6_tcp_udp_icmp_validate_checksum (vm, p0);
              good_l4_checksum0 =
                (flags0 & IP_BUFFER_L4_CHECKSUM_CORRECT) != 0;
            }

          error0 = IP6_ERROR_UNKNOWN_PROTOCOL;

          error0 = len_diff0 < 0 ? IP6_ERROR_UDP_LENGTH : error0;

          ASSERT (IP6_ERROR_UDP_CHECKSUM + IP_BUILTIN_PROTOCOL_UDP == IP6_ERROR_UDP_CHECKSUM);
          ASSERT (IP6_ERROR_UDP_CHECKSUM + IP_BUILTIN_PROTOCOL_ICMP == IP6_ERROR_ICMP_CHECKSUM);
          error0 = (! good_l4_checksum0
                    ? IP6_ERROR_UDP_CHECKSUM + type0
                    : error0);

          /* If this is a neighbor solicitation (ICMP), skip source RPF check */
          if (error0 == IP6_ERROR_UNKNOWN_PROTOCOL &&
              type0 != IP_BUILTIN_PROTOCOL_ICMP &&
              !ip6_address_is_link_local_unicast(&ip0->src_address))
            {
              u32 src_adj_index0 = ip6_src_lookup_for_packet (im, p0, ip0);
              error0 = (ADJ_INDEX_INVALID == src_adj_index0
                        ? IP6_ERROR_SRC_LOOKUP_MISS
                        : error0);
            }

          next0 = error0 != IP6_ERROR_UNKNOWN_PROTOCOL ? IP_LOCAL_NEXT_DROP : next0;

          p0->error = error_node->errors[error0];

          vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
                                           to_next, n_left_to_next,
                                           pi0, next0);
        }

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  return frame->n_vectors;
}

VLIB_REGISTER_NODE (ip6_local_node,static) = {
  .function = ip6_local,
  .name = "ip6-local",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_forward_next_trace,

  .n_next_nodes = IP_LOCAL_N_NEXT,
  .next_nodes = {
    [IP_LOCAL_NEXT_DROP] = "error-drop",
    [IP_LOCAL_NEXT_PUNT] = "error-punt",
    [IP_LOCAL_NEXT_UDP_LOOKUP] = "ip6-udp-lookup",
    [IP_LOCAL_NEXT_ICMP] = "ip6-icmp-input",
  },
};

VLIB_NODE_FUNCTION_MULTIARCH (ip6_local_node, ip6_local)

void ip6_register_protocol (u32 protocol, u32 node_index)
{
  vlib_main_t * vm = vlib_get_main();
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t * lm = &im->lookup_main;

  ASSERT (protocol < ARRAY_LEN (lm->local_next_by_ip_protocol));
  lm->local_next_by_ip_protocol[protocol] = vlib_node_add_next (vm, ip6_local_node.index, node_index);
}

typedef enum {
  IP6_DISCOVER_NEIGHBOR_NEXT_DROP,
  IP6_DISCOVER_NEIGHBOR_NEXT_REPLY_TX,
  IP6_DISCOVER_NEIGHBOR_N_NEXT,
} ip6_discover_neighbor_next_t;

typedef enum {
  IP6_DISCOVER_NEIGHBOR_ERROR_DROP,
  IP6_DISCOVER_NEIGHBOR_ERROR_REQUEST_SENT,
  IP6_DISCOVER_NEIGHBOR_ERROR_NO_SOURCE_ADDRESS,
} ip6_discover_neighbor_error_t;

static uword
ip6_discover_neighbor_inline (vlib_main_t * vm,
                              vlib_node_runtime_t * node,
                              vlib_frame_t * frame,
                              int is_glean)
{
  vnet_main_t * vnm = vnet_get_main();
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t * lm = &im->lookup_main;
  u32 * from, * to_next_drop;
  uword n_left_from, n_left_to_next_drop;
  static f64 time_last_seed_change = -1e100;
  static u32 hash_seeds[3];
  static uword hash_bitmap[256 / BITS (uword)];
  f64 time_now;
  int bogus_length;

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    ip6_forward_next_trace (vm, node, frame, VLIB_TX);

  time_now = vlib_time_now (vm);
  if (time_now - time_last_seed_change > 1e-3)
    {
      uword i;
      u32 * r = clib_random_buffer_get_data (&vm->random_buffer,
                                             sizeof (hash_seeds));
      for (i = 0; i < ARRAY_LEN (hash_seeds); i++)
        hash_seeds[i] = r[i];

      /* Mark all hash keys as been not-seen before. */
      for (i = 0; i < ARRAY_LEN (hash_bitmap); i++)
        hash_bitmap[i] = 0;

      time_last_seed_change = time_now;
    }

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;

  while (n_left_from > 0)
    {
      vlib_get_next_frame (vm, node, IP6_DISCOVER_NEIGHBOR_NEXT_DROP,
                           to_next_drop, n_left_to_next_drop);

      while (n_left_from > 0 && n_left_to_next_drop > 0)
        {
          vlib_buffer_t * p0;
          ip6_header_t * ip0;
          u32 pi0, adj_index0, a0, b0, c0, m0, sw_if_index0, drop0;
          uword bm0;
          ip_adjacency_t * adj0;
          vnet_hw_interface_t * hw_if0;
          u32 next0;

          pi0 = from[0];

          p0 = vlib_get_buffer (vm, pi0);

          adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];

          ip0 = vlib_buffer_get_current (p0);

          adj0 = ip_get_adjacency (lm, adj_index0);

          if (!is_glean)
            {
              ip0->dst_address.as_u64[0] = adj0->sub_type.nbr.next_hop.ip6.as_u64[0];
              ip0->dst_address.as_u64[1] = adj0->sub_type.nbr.next_hop.ip6.as_u64[1];
            }

          a0 = hash_seeds[0];
          b0 = hash_seeds[1];
          c0 = hash_seeds[2];

          sw_if_index0 = adj0->rewrite_header.sw_if_index;
          vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;

          a0 ^= sw_if_index0;
          b0 ^= ip0->dst_address.as_u32[0];
          c0 ^= ip0->dst_address.as_u32[1];

          hash_v3_mix32 (a0, b0, c0);

          b0 ^= ip0->dst_address.as_u32[2];
          c0 ^= ip0->dst_address.as_u32[3];

          hash_v3_finalize32 (a0, b0, c0);

          c0 &= BITS (hash_bitmap) - 1;
          c0 = c0 / BITS (uword);
          m0 = (uword) 1 << (c0 % BITS (uword));

          bm0 = hash_bitmap[c0];
          drop0 = (bm0 & m0) != 0;

          /* Mark it as seen. */
          hash_bitmap[c0] = bm0 | m0;

          from += 1;
          n_left_from -= 1;
          to_next_drop[0] = pi0;
          to_next_drop += 1;
          n_left_to_next_drop -= 1;

          hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);

          /* If the interface is link-down, drop the pkt */
          if (!(hw_if0->flags & VNET_HW_INTERFACE_FLAG_LINK_UP))
            drop0 = 1;

          p0->error =
            node->errors[drop0 ? IP6_DISCOVER_NEIGHBOR_ERROR_DROP
                         : IP6_DISCOVER_NEIGHBOR_ERROR_REQUEST_SENT];
          if (drop0)
            continue;

          /*
           * the adj has been updated to a rewrite but the node the DPO that got
           * us here hasn't - yet. no big deal. we'll drop while we wait.
           */
          if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
            continue;

          {
            u32 bi0 = 0;
            icmp6_neighbor_solicitation_header_t * h0;
            vlib_buffer_t * b0;

            h0 = vlib_packet_template_get_packet
              (vm, &im->discover_neighbor_packet_template, &bi0);

            /*
             * Build ethernet header.
             * Choose source address based on destination lookup
             * adjacency.
             */
            if (ip6_src_address_for_packet (lm,
                                            sw_if_index0,
                                            &h0->ip.src_address))
              {
                /* There is no address on the interface */
                p0->error = node->errors[IP6_DISCOVER_NEIGHBOR_ERROR_NO_SOURCE_ADDRESS];
                vlib_buffer_free(vm, &bi0, 1);
                continue;
              }

            /*
             * Destination address is a solicited node multicast address.
             * We need to fill in
             * the low 24 bits with low 24 bits of target's address.
             */
            h0->ip.dst_address.as_u8[13] = ip0->dst_address.as_u8[13];
            h0->ip.dst_address.as_u8[14] = ip0->dst_address.as_u8[14];
            h0->ip.dst_address.as_u8[15] = ip0->dst_address.as_u8[15];

            h0->neighbor.target_address = ip0->dst_address;

            clib_memcpy (h0->link_layer_option.ethernet_address,
                    hw_if0->hw_address, vec_len (hw_if0->hw_address));

            /* $$$$ appears we need this; why is the checksum non-zero? */
            h0->neighbor.icmp.checksum = 0;
            h0->neighbor.icmp.checksum =
              ip6_tcp_udp_icmp_compute_checksum (vm, 0, &h0->ip,
                                                 &bogus_length);

            ASSERT (bogus_length == 0);

            vlib_buffer_copy_trace_flag (vm, p0, bi0);
            b0 = vlib_get_buffer (vm, bi0);
            vnet_buffer (b0)->sw_if_index[VLIB_TX]
              = vnet_buffer (p0)->sw_if_index[VLIB_TX];

            /* Add rewrite/encap string. */
            vnet_rewrite_one_header (adj0[0], h0,
                                     sizeof (ethernet_header_t));
            vlib_buffer_advance (b0, -adj0->rewrite_header.data_bytes);

            next0 = IP6_DISCOVER_NEIGHBOR_NEXT_REPLY_TX;

            vlib_set_next_frame_buffer (vm, node, next0, bi0);
          }
        }

      vlib_put_next_frame (vm, node, IP6_DISCOVER_NEIGHBOR_NEXT_DROP,
                           n_left_to_next_drop);
    }

  return frame->n_vectors;
}

static uword
ip6_discover_neighbor (vlib_main_t * vm,
                       vlib_node_runtime_t * node,
                       vlib_frame_t * frame)
{
    return (ip6_discover_neighbor_inline(vm, node, frame, 0));
}

static uword
ip6_glean (vlib_main_t * vm,
           vlib_node_runtime_t * node,
           vlib_frame_t * frame)
{
    return (ip6_discover_neighbor_inline(vm, node, frame, 1));
}

static char * ip6_discover_neighbor_error_strings[] = {
  [IP6_DISCOVER_NEIGHBOR_ERROR_DROP] = "address overflow drops",
  [IP6_DISCOVER_NEIGHBOR_ERROR_REQUEST_SENT]
  = "neighbor solicitations sent",
  [IP6_DISCOVER_NEIGHBOR_ERROR_NO_SOURCE_ADDRESS]
    = "no source address for ND solicitation",
};

VLIB_REGISTER_NODE (ip6_discover_neighbor_node) = {
  .function = ip6_discover_neighbor,
  .name = "ip6-discover-neighbor",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_forward_next_trace,

  .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
  .error_strings = ip6_discover_neighbor_error_strings,

  .n_next_nodes = IP6_DISCOVER_NEIGHBOR_N_NEXT,
  .next_nodes = {
    [IP6_DISCOVER_NEIGHBOR_NEXT_DROP] = "error-drop",
    [IP6_DISCOVER_NEIGHBOR_NEXT_REPLY_TX] = "interface-output",
  },
};

VLIB_REGISTER_NODE (ip6_glean_node) = {
  .function = ip6_glean,
  .name = "ip6-glean",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_forward_next_trace,

  .n_errors = ARRAY_LEN (ip6_discover_neighbor_error_strings),
  .error_strings = ip6_discover_neighbor_error_strings,

  .n_next_nodes = IP6_DISCOVER_NEIGHBOR_N_NEXT,
  .next_nodes = {
    [IP6_DISCOVER_NEIGHBOR_NEXT_DROP] = "error-drop",
    [IP6_DISCOVER_NEIGHBOR_NEXT_REPLY_TX] = "interface-output",
  },
};

clib_error_t *
ip6_probe_neighbor (vlib_main_t * vm, ip6_address_t * dst, u32 sw_if_index)
{
  vnet_main_t * vnm = vnet_get_main();
  ip6_main_t * im = &ip6_main;
  icmp6_neighbor_solicitation_header_t * h;
  ip6_address_t * src;
  ip_interface_address_t * ia;
  ip_adjacency_t * adj;
  vnet_hw_interface_t * hi;
  vnet_sw_interface_t * si;
  vlib_buffer_t * b;
  u32 bi = 0;
  int bogus_length;

  si = vnet_get_sw_interface (vnm, sw_if_index);

  if (!(si->flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP))
    {
      return clib_error_return (0, "%U: interface %U down",
                                format_ip6_address, dst,
                                format_vnet_sw_if_index_name, vnm,
                                sw_if_index);
    }

  src = ip6_interface_address_matching_destination (im, dst, sw_if_index, &ia);
  if (! src)
    {
      vnm->api_errno = VNET_API_ERROR_NO_MATCHING_INTERFACE;
      return clib_error_return
        (0, "no matching interface address for destination %U (interface %U)",
         format_ip6_address, dst,
         format_vnet_sw_if_index_name, vnm, sw_if_index);
    }

  h = vlib_packet_template_get_packet (vm, &im->discover_neighbor_packet_template, &bi);

  hi = vnet_get_sup_hw_interface (vnm, sw_if_index);

  /* Destination address is a solicited node multicast address.  We need to fill in
     the low 24 bits with low 24 bits of target's address. */
  h->ip.dst_address.as_u8[13] = dst->as_u8[13];
  h->ip.dst_address.as_u8[14] = dst->as_u8[14];
  h->ip.dst_address.as_u8[15] = dst->as_u8[15];

  h->ip.src_address = src[0];
  h->neighbor.target_address = dst[0];

  clib_memcpy (h->link_layer_option.ethernet_address, hi->hw_address, vec_len (hi->hw_address));

  h->neighbor.icmp.checksum =
    ip6_tcp_udp_icmp_compute_checksum (vm, 0, &h->ip, &bogus_length);
  ASSERT(bogus_length == 0);

  b = vlib_get_buffer (vm, bi);
  vnet_buffer (b)->sw_if_index[VLIB_RX] = vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;

  /* Add encapsulation string for software interface (e.g. ethernet header). */
  adj = ip_get_adjacency (&im->lookup_main, ia->neighbor_probe_adj_index);
  vnet_rewrite_one_header (adj[0], h, sizeof (ethernet_header_t));
  vlib_buffer_advance (b, -adj->rewrite_header.data_bytes);

  {
    vlib_frame_t * f = vlib_get_frame_to_node (vm, hi->output_node_index);
    u32 * to_next = vlib_frame_vector_args (f);
    to_next[0] = bi;
    f->n_vectors = 1;
    vlib_put_frame_to_node (vm, hi->output_node_index, f);
  }

  return /* no error */ 0;
}

typedef enum {
  IP6_REWRITE_NEXT_DROP,
  IP6_REWRITE_NEXT_ICMP_ERROR,
} ip6_rewrite_next_t;

always_inline uword
ip6_rewrite_inline (vlib_main_t * vm,
                    vlib_node_runtime_t * node,
                    vlib_frame_t * frame,
                    int rewrite_for_locally_received_packets,
                    int is_midchain)
{
  ip_lookup_main_t * lm = &ip6_main.lookup_main;
  u32 * from = vlib_frame_vector_args (frame);
  u32 n_left_from, n_left_to_next, * to_next, next_index;
  vlib_node_runtime_t * error_node = vlib_node_get_runtime (vm, ip6_input_node.index);
  vlib_rx_or_tx_t adj_rx_tx = rewrite_for_locally_received_packets ? VLIB_RX : VLIB_TX;
  vnet_feature_config_main_t * cm = &lm->feature_config_mains[VNET_IP_TX_FEAT];

  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;
  u32 cpu_index = os_get_cpu_number();

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

      while (n_left_from >= 4 && n_left_to_next >= 2)
        {
          ip_adjacency_t * adj0, * adj1;
          vlib_buffer_t * p0, * p1;
          ip6_header_t * ip0, * ip1;
          u32 pi0, rw_len0, next0, error0, adj_index0;
          u32 pi1, rw_len1, next1, error1, adj_index1;
          u32 tx_sw_if_index0, tx_sw_if_index1;

          /* 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);

            CLIB_PREFETCH (p2->pre_data, 32, STORE);
            CLIB_PREFETCH (p3->pre_data, 32, STORE);

            CLIB_PREFETCH (p2->data, sizeof (ip0[0]), STORE);
            CLIB_PREFETCH (p3->data, sizeof (ip0[0]), 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);

          adj_index0 = vnet_buffer (p0)->ip.adj_index[adj_rx_tx];
          adj_index1 = vnet_buffer (p1)->ip.adj_index[adj_rx_tx];

          /* We should never rewrite a pkt using the MISS adjacency */
          ASSERT(adj_index0 && adj_index1);

          ip0 = vlib_buffer_get_current (p0);
          ip1 = vlib_buffer_get_current (p1);

          error0 = error1 = IP6_ERROR_NONE;
          next0 = next1 = IP6_REWRITE_NEXT_DROP;

          if (! rewrite_for_locally_received_packets)
            {
              i32 hop_limit0 = ip0->hop_limit, hop_limit1 = ip1->hop_limit;

              /* Input node should have reject packets with hop limit 0. */
              ASSERT (ip0->hop_limit > 0);
              ASSERT (ip1->hop_limit > 0);

              hop_limit0 -= 1;
              hop_limit1 -= 1;

              ip0->hop_limit = hop_limit0;
              ip1->hop_limit = hop_limit1;

              /*
               * If the hop count drops below 1 when forwarding, generate
               * an ICMP response.
               */
              if (PREDICT_FALSE(hop_limit0 <= 0))
                {
                  error0 = IP6_ERROR_TIME_EXPIRED;
                  next0 = IP6_REWRITE_NEXT_ICMP_ERROR;
                  vnet_buffer (p0)->sw_if_index[VLIB_TX] = (u32)~0;
                  icmp6_error_set_vnet_buffer(p0, ICMP6_time_exceeded,
                        ICMP6_time_exceeded_ttl_exceeded_in_transit, 0);
                }
              if (PREDICT_FALSE(hop_limit1 <= 0))
                {
                  error1 = IP6_ERROR_TIME_EXPIRED;
                  next1 = IP6_REWRITE_NEXT_ICMP_ERROR;
                  vnet_buffer (p1)->sw_if_index[VLIB_TX] = (u32)~0;
                  icmp6_error_set_vnet_buffer(p1, ICMP6_time_exceeded,
                        ICMP6_time_exceeded_ttl_exceeded_in_transit, 0);
                }
            }

          adj0 = ip_get_adjacency (lm, adj_index0);
          adj1 = ip_get_adjacency (lm, adj_index1);

          rw_len0 = adj0[0].rewrite_header.data_bytes;
          rw_len1 = adj1[0].rewrite_header.data_bytes;
          vnet_buffer(p0)->ip.save_rewrite_length = rw_len0;
          vnet_buffer(p1)->ip.save_rewrite_length = rw_len1;

          vlib_increment_combined_counter (&adjacency_counters,
                                           cpu_index,
                                           adj_index0,
                                           /* packet increment */ 0,
                                           /* byte increment */ rw_len0);
          vlib_increment_combined_counter (&adjacency_counters,
                                           cpu_index,
                                           adj_index1,
                                           /* packet increment */ 0,
                                           /* byte increment */ rw_len1);

          /* Check MTU of outgoing interface. */
          error0 = (vlib_buffer_length_in_chain (vm, p0) > adj0[0].rewrite_header.max_l3_packet_bytes
                    ? IP6_ERROR_MTU_EXCEEDED
                    : error0);
          error1 = (vlib_buffer_length_in_chain (vm, p1) > adj1[0].rewrite_header.max_l3_packet_bytes
                    ? IP6_ERROR_MTU_EXCEEDED
                    : error1);

          /* Don't adjust the buffer for hop count issue; icmp-error node
           * wants to see the IP headerr */
          if (PREDICT_TRUE(error0 == IP6_ERROR_NONE))
            {
              p0->current_data -= rw_len0;
              p0->current_length += rw_len0;

              tx_sw_if_index0 = adj0[0].rewrite_header.sw_if_index;
              vnet_buffer (p0)->sw_if_index[VLIB_TX] =
                  tx_sw_if_index0;
              next0 = adj0[0].rewrite_header.next_index;

              if (PREDICT_FALSE
                  (clib_bitmap_get (lm->tx_sw_if_has_ip_output_features,
                                    tx_sw_if_index0)))
                {
                  p0->current_config_index =
                    vec_elt (cm->config_index_by_sw_if_index,
                             tx_sw_if_index0);
                  vnet_get_config_data (&cm->config_main,
                                        &p0->current_config_index,
                                        &next0,
                                        /* # bytes of config data */ 0);
                }
            }
          if (PREDICT_TRUE(error1 == IP6_ERROR_NONE))
            {
              p1->current_data -= rw_len1;
              p1->current_length += rw_len1;

              tx_sw_if_index1 = adj1[0].rewrite_header.sw_if_index;
              vnet_buffer (p1)->sw_if_index[VLIB_TX] =
                  tx_sw_if_index1;
              next1 = adj1[0].rewrite_header.next_index;

              if (PREDICT_FALSE
                  (clib_bitmap_get (lm->tx_sw_if_has_ip_output_features,
                                    tx_sw_if_index1)))
                {
                  p1->current_config_index =
                    vec_elt (cm->config_index_by_sw_if_index,
                             tx_sw_if_index1);
                  vnet_get_config_data (&cm->config_main,
                                        &p1->current_config_index,
                                        &next1,
                                        /* # bytes of config data */ 0);
                }
            }

          /* Guess we are only writing on simple Ethernet header. */
          vnet_rewrite_two_headers (adj0[0], adj1[0],
                                    ip0, ip1,
                                    sizeof (ethernet_header_t));

          if (is_midchain)
          {
              adj0->sub_type.midchain.fixup_func(vm, adj0, p0);
              adj1->sub_type.midchain.fixup_func(vm, adj1, p1);
          }

          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)
        {
          ip_adjacency_t * adj0;
          vlib_buffer_t * p0;
          ip6_header_t * ip0;
          u32 pi0, rw_len0;
          u32 adj_index0, next0, error0;
          u32 tx_sw_if_index0;

          pi0 = to_next[0] = from[0];

          p0 = vlib_get_buffer (vm, pi0);

          adj_index0 = vnet_buffer (p0)->ip.adj_index[adj_rx_tx];

          /* We should never rewrite a pkt using the MISS adjacency */
          ASSERT(adj_index0);

          adj0 = ip_get_adjacency (lm, adj_index0);

          ip0 = vlib_buffer_get_current (p0);

          error0 = IP6_ERROR_NONE;
          next0 = IP6_REWRITE_NEXT_DROP;

          /* Check hop limit */
          if (! rewrite_for_locally_received_packets)
            {
              i32 hop_limit0 = ip0->hop_limit;

              ASSERT (ip0->hop_limit > 0);

              hop_limit0 -= 1;

              ip0->hop_limit = hop_limit0;

              if (PREDICT_FALSE(hop_limit0 <= 0))
                {
                  /*
                   * If the hop count drops below 1 when forwarding, generate
                   * an ICMP response.
                   */
                  error0 = IP6_ERROR_TIME_EXPIRED;
                  next0 = IP6_REWRITE_NEXT_ICMP_ERROR;
                  vnet_buffer (p0)->sw_if_index[VLIB_TX] = (u32)~0;
                  icmp6_error_set_vnet_buffer(p0, ICMP6_time_exceeded,
                        ICMP6_time_exceeded_ttl_exceeded_in_transit, 0);
                }
            }

          /* Guess we are only writing on simple Ethernet header. */
          vnet_rewrite_one_header (adj0[0], ip0, sizeof (ethernet_header_t));

          /* Update packet buffer attributes/set output interface. */
          rw_len0 = adj0[0].rewrite_header.data_bytes;
          vnet_buffer(p0)->ip.save_rewrite_length = rw_len0;

          vlib_increment_combined_counter (&adjacency_counters,
                                           cpu_index,
                                           adj_index0,
                                           /* packet increment */ 0,
                                           /* byte increment */ rw_len0);

          /* Check MTU of outgoing interface. */
          error0 = (vlib_buffer_length_in_chain (vm, p0) > adj0[0].rewrite_header.max_l3_packet_bytes
                    ? IP6_ERROR_MTU_EXCEEDED
                    : error0);

          /* Don't adjust the buffer for hop count issue; icmp-error node
           * wants to see the IP headerr */
          if (PREDICT_TRUE(error0 == IP6_ERROR_NONE))
            {
              p0->current_data -= rw_len0;
              p0->current_length += rw_len0;

              tx_sw_if_index0 = adj0[0].rewrite_header.sw_if_index;

              vnet_buffer (p0)->sw_if_index[VLIB_TX] = tx_sw_if_index0;
              next0 = adj0[0].rewrite_header.next_index;

              if (PREDICT_FALSE
                  (clib_bitmap_get (lm->tx_sw_if_has_ip_output_features,
                                    tx_sw_if_index0)))
                  {
                    p0->current_config_index =
                      vec_elt (cm->config_index_by_sw_if_index,
                               tx_sw_if_index0);
                    vnet_get_config_data (&cm->config_main,
                                          &p0->current_config_index,
                                          &next0,
                                          /* # bytes of config data */ 0);
                  }
            }

          if (is_midchain)
          {
              adj0->sub_type.midchain.fixup_func(vm, adj0, p0);
          }

          p0->error = error_node->errors[error0];

          from += 1;
          n_left_from -= 1;
          to_next += 1;
          n_left_to_next -= 1;

          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);
    }

  /* Need to do trace after rewrites to pick up new packet data. */
  if (node->flags & VLIB_NODE_FLAG_TRACE)
    ip6_forward_next_trace (vm, node, frame, adj_rx_tx);

  return frame->n_vectors;
}

static uword
ip6_rewrite_transit (vlib_main_t * vm,
                     vlib_node_runtime_t * node,
                     vlib_frame_t * frame)
{
  return ip6_rewrite_inline (vm, node, frame,
                             /* rewrite_for_locally_received_packets */ 0,
                             /* midchain */ 0);
}

static uword
ip6_rewrite_local (vlib_main_t * vm,
                   vlib_node_runtime_t * node,
                   vlib_frame_t * frame)
{
  return ip6_rewrite_inline (vm, node, frame,
                             /* rewrite_for_locally_received_packets */ 1,
                             /* midchain */ 0);
}

static uword
ip6_midchain (vlib_main_t * vm,
              vlib_node_runtime_t * node,
              vlib_frame_t * frame)
{
  return ip6_rewrite_inline (vm, node, frame,
                             /* rewrite_for_locally_received_packets */ 0,
                             /* midchain */ 1);
}

VLIB_REGISTER_NODE (ip6_midchain_node) = {
  .function = ip6_midchain,
  .name = "ip6-midchain",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_forward_next_trace,

  .sibling_of = "ip6-rewrite",
};

VLIB_NODE_FUNCTION_MULTIARCH (ip6_midchain_node, ip6_midchain)

VLIB_REGISTER_NODE (ip6_rewrite_node) = {
  .function = ip6_rewrite_transit,
  .name = "ip6-rewrite",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_rewrite_trace,

  .n_next_nodes = 2,
  .next_nodes = {
    [IP6_REWRITE_NEXT_DROP] = "error-drop",
    [IP6_REWRITE_NEXT_ICMP_ERROR] = "ip6-icmp-error",
  },
};

VLIB_NODE_FUNCTION_MULTIARCH (ip6_rewrite_node, ip6_rewrite_transit);

VLIB_REGISTER_NODE (ip6_rewrite_local_node) = {
  .function = ip6_rewrite_local,
  .name = "ip6-rewrite-local",
  .vector_size = sizeof (u32),

  .sibling_of = "ip6-rewrite",

  .format_trace = format_ip6_rewrite_trace,

  .n_next_nodes = 0,
};

VLIB_NODE_FUNCTION_MULTIARCH (ip6_rewrite_local_node, ip6_rewrite_local);

/*
 * Hop-by-Hop handling
 */

ip6_hop_by_hop_main_t ip6_hop_by_hop_main;

#define foreach_ip6_hop_by_hop_error \
_(PROCESSED, "pkts with ip6 hop-by-hop options") \
_(FORMAT, "incorrectly formatted hop-by-hop options") \
_(UNKNOWN_OPTION, "unknown ip6 hop-by-hop options")

typedef enum {
#define _(sym,str) IP6_HOP_BY_HOP_ERROR_##sym,
  foreach_ip6_hop_by_hop_error
#undef _
  IP6_HOP_BY_HOP_N_ERROR,
} ip6_hop_by_hop_error_t;

/*
 * Primary h-b-h handler trace support
 * We work pretty hard on the problem for obvious reasons
 */
typedef struct {
  u32 next_index;
  u32 trace_len;
  u8 option_data[256];
} ip6_hop_by_hop_trace_t;

vlib_node_registration_t ip6_hop_by_hop_node;

static char * ip6_hop_by_hop_error_strings[] = {
#define _(sym,string) string,
  foreach_ip6_hop_by_hop_error
#undef _
};

static u8 *
format_ip6_hop_by_hop_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 *);
  ip6_hop_by_hop_trace_t * t = va_arg (*args, ip6_hop_by_hop_trace_t *);
  ip6_hop_by_hop_header_t *hbh0;
  ip6_hop_by_hop_option_t *opt0, *limit0;
  ip6_hop_by_hop_main_t *hm = &ip6_hop_by_hop_main;

  u8 type0;

  hbh0 = (ip6_hop_by_hop_header_t *)t->option_data;

  s = format (s, "IP6_HOP_BY_HOP: next index %d len %d traced %d",
              t->next_index, (hbh0->length+1)<<3, t->trace_len);

  opt0 = (ip6_hop_by_hop_option_t *) (hbh0+1);
  limit0 = (ip6_hop_by_hop_option_t *) ((u8 *)hbh0) + t->trace_len;

  while (opt0 < limit0) {
    type0 = opt0->type;
    switch (type0) {
    case 0: /* Pad, just stop */
      opt0 = (ip6_hop_by_hop_option_t *) ((u8 *)opt0) + 1;
      break;

    default:
      if (hm->trace[type0]) {
        s = (*hm->trace[type0])(s, opt0);
      } else {
        s = format (s, "\n    unrecognized option %d length %d", type0, opt0->length);
      }
      opt0 = (ip6_hop_by_hop_option_t *) (((u8 *)opt0) + opt0->length + sizeof (ip6_hop_by_hop_option_t));
      break;
    }
  }
  return s;
}

always_inline u8 ip6_scan_hbh_options (
                                       vlib_buffer_t * b0,
                                       ip6_header_t *ip0,
                                       ip6_hop_by_hop_header_t *hbh0,
                                       ip6_hop_by_hop_option_t *opt0,
                                       ip6_hop_by_hop_option_t *limit0,
                                       u32 *next0)
{
  ip6_hop_by_hop_main_t *hm = &ip6_hop_by_hop_main;
  u8 type0;
  u8 error0 = 0;

  while (opt0 < limit0)
    {
      type0 = opt0->type;
      switch (type0)
        {
        case 0: /* Pad1 */
          opt0 = (ip6_hop_by_hop_option_t *) ((u8 *)opt0) + 1;
          continue;
        case 1: /* PadN */
          break;
        default:
          if (hm->options[type0])
            {
              if ((*hm->options[type0])(b0, ip0, opt0) < 0)
                {
                  error0 = IP6_HOP_BY_HOP_ERROR_FORMAT;
                  return(error0);
                }
            }
          else
            {
              /* Unrecognized mandatory option, check the two high order bits */
              switch (opt0->type & HBH_OPTION_TYPE_HIGH_ORDER_BITS)
                {
                case HBH_OPTION_TYPE_SKIP_UNKNOWN:
                  break;
                case HBH_OPTION_TYPE_DISCARD_UNKNOWN:
                  error0 = IP6_HOP_BY_HOP_ERROR_UNKNOWN_OPTION;
                  *next0 = IP_LOOKUP_NEXT_DROP;
                  break;
                case HBH_OPTION_TYPE_DISCARD_UNKNOWN_ICMP:
                  error0 = IP6_HOP_BY_HOP_ERROR_UNKNOWN_OPTION;
                  *next0 = IP_LOOKUP_NEXT_ICMP_ERROR;
                  icmp6_error_set_vnet_buffer(b0, ICMP6_parameter_problem,
                                              ICMP6_parameter_problem_unrecognized_option, (u8 *)opt0 - (u8 *)ip0);
                  break;
                case HBH_OPTION_TYPE_DISCARD_UNKNOWN_ICMP_NOT_MCAST:
                  error0 = IP6_HOP_BY_HOP_ERROR_UNKNOWN_OPTION;
                  if (!ip6_address_is_multicast(&ip0->dst_address))
                    {
                      *next0 =  IP_LOOKUP_NEXT_ICMP_ERROR;
                      icmp6_error_set_vnet_buffer(b0, ICMP6_parameter_problem,
                                                  ICMP6_parameter_problem_unrecognized_option, (u8 *)opt0 - (u8 *)ip0);
                    }
                  else
                    {
                      *next0 =  IP_LOOKUP_NEXT_DROP;
                    }
                  break;
                }
              return(error0);
            }
        }
      opt0 = (ip6_hop_by_hop_option_t *) (((u8 *)opt0) + opt0->length + sizeof (ip6_hop_by_hop_option_t));
    }
  return(error0);
}

/*
 * Process the Hop-by-Hop Options header
 */
static uword
ip6_hop_by_hop (vlib_main_t * vm,
                vlib_node_runtime_t * node,
                vlib_frame_t * frame)
{
  vlib_node_runtime_t *error_node = vlib_node_get_runtime(vm, ip6_hop_by_hop_node.index);
  ip6_hop_by_hop_main_t *hm = &ip6_hop_by_hop_main;
  u32 n_left_from, *from, *to_next;
  ip_lookup_next_t next_index;
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t *lm = &im->lookup_main;

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

  while (n_left_from > 0) {
    u32 n_left_to_next;

    vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

    while (n_left_from >= 4 && n_left_to_next >= 2) {
      u32 bi0, bi1;
      vlib_buffer_t * b0, *b1;
      u32 next0, next1;
      ip6_header_t * ip0, *ip1;
      ip6_hop_by_hop_header_t *hbh0, *hbh1;
      ip6_hop_by_hop_option_t *opt0, *limit0, *opt1, *limit1;
      u8 error0 = 0, error1 = 0;

      /* 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);

        CLIB_PREFETCH (p2->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
        CLIB_PREFETCH (p3->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
      }

      /* Speculatively enqueue b0, b1 to the current next frame */
      to_next[0] = bi0 = from[0];
      to_next[1] = bi1 = from[1];
      from += 2;
      to_next += 2;
      n_left_from -= 2;
      n_left_to_next -= 2;

      b0 = vlib_get_buffer (vm, bi0);
      b1 = vlib_get_buffer (vm, bi1);

      /* Default use the next_index from the adjacency. A HBH option rarely redirects to a different node */
      u32 adj_index0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];
      ip_adjacency_t *adj0 = ip_get_adjacency(lm, adj_index0);
      u32 adj_index1 = vnet_buffer(b1)->ip.adj_index[VLIB_TX];
      ip_adjacency_t *adj1 = ip_get_adjacency(lm, adj_index1);

      /* Default use the next_index from the adjacency. A HBH option rarely redirects to a different node */
      next0 = adj0->lookup_next_index;
      next1 = adj1->lookup_next_index;

      ip0 = vlib_buffer_get_current (b0);
      ip1 = vlib_buffer_get_current (b1);
      hbh0 = (ip6_hop_by_hop_header_t *)(ip0+1);
      hbh1 = (ip6_hop_by_hop_header_t *)(ip1+1);
      opt0 = (ip6_hop_by_hop_option_t *)(hbh0+1);
      opt1 = (ip6_hop_by_hop_option_t *)(hbh1+1);
      limit0 = (ip6_hop_by_hop_option_t *)((u8 *)hbh0 + ((hbh0->length + 1) << 3));
      limit1 = (ip6_hop_by_hop_option_t *)((u8 *)hbh1 + ((hbh1->length + 1) << 3));

      /*
       * Basic validity checks
       */
      if ((hbh0->length + 1) << 3 > clib_net_to_host_u16(ip0->payload_length)) {
        error0 = IP6_HOP_BY_HOP_ERROR_FORMAT;
        next0 = IP_LOOKUP_NEXT_DROP;
        goto outdual;
      }
      /* Scan the set of h-b-h options, process ones that we understand */
      error0 = ip6_scan_hbh_options(b0, ip0, hbh0, opt0, limit0, &next0);

      if ((hbh1->length + 1) << 3 > clib_net_to_host_u16(ip1->payload_length)) {
        error1 = IP6_HOP_BY_HOP_ERROR_FORMAT;
        next1 = IP_LOOKUP_NEXT_DROP;
        goto outdual;
      }
      /* Scan the set of h-b-h options, process ones that we understand */
      error1 = ip6_scan_hbh_options(b1,ip1,hbh1,opt1,limit1, &next1);

    outdual:
      /* Has the classifier flagged this buffer for special treatment? */
      if (PREDICT_FALSE((error0 == 0) && (vnet_buffer(b0)->l2_classify.opaque_index & OI_DECAP)))
        next0 = hm->next_override;

      /* Has the classifier flagged this buffer for special treatment? */
      if (PREDICT_FALSE((error1 == 0) && (vnet_buffer(b1)->l2_classify.opaque_index & OI_DECAP)))
        next1 = hm->next_override;

      if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)))
        {
          if (b0->flags & VLIB_BUFFER_IS_TRACED) {
            ip6_hop_by_hop_trace_t *t = vlib_add_trace(vm, node, b0, sizeof (*t));
            u32 trace_len = (hbh0->length + 1) << 3;
            t->next_index = next0;
            /* Capture the h-b-h option verbatim */
            trace_len = trace_len < ARRAY_LEN(t->option_data) ? trace_len : ARRAY_LEN(t->option_data);
            t->trace_len = trace_len;
            clib_memcpy(t->option_data, hbh0, trace_len);
          }
          if (b1->flags & VLIB_BUFFER_IS_TRACED) {
            ip6_hop_by_hop_trace_t *t = vlib_add_trace(vm, node, b1, sizeof (*t));
            u32 trace_len = (hbh1->length + 1) << 3;
            t->next_index = next1;
            /* Capture the h-b-h option verbatim */
            trace_len = trace_len < ARRAY_LEN(t->option_data) ? trace_len : ARRAY_LEN(t->option_data);
            t->trace_len = trace_len;
            clib_memcpy(t->option_data, hbh1, trace_len);
          }

        }

      b0->error = error_node->errors[error0];
      b1->error = error_node->errors[error1];

      /* verify speculative enqueue, maybe switch current next frame */
      vlib_validate_buffer_enqueue_x2 (vm, node, next_index, to_next, n_left_to_next, bi0,
                                       bi1,next0, next1);
    }

    while (n_left_from > 0 && n_left_to_next > 0) {
      u32 bi0;
      vlib_buffer_t * b0;
      u32 next0;
      ip6_header_t * ip0;
      ip6_hop_by_hop_header_t *hbh0;
      ip6_hop_by_hop_option_t *opt0, *limit0;
      u8 error0 = 0;

      /* Speculatively enqueue b0 to the current next frame */
      bi0 = from[0];
      to_next[0] = bi0;
      from += 1;
      to_next += 1;
      n_left_from -= 1;
      n_left_to_next -= 1;

      b0 = vlib_get_buffer (vm, bi0);
      /*
       * Default use the next_index from the adjacency.
       * A HBH option rarely redirects to a different node 
       */
      u32 adj_index0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];
      ip_adjacency_t *adj0 = ip_get_adjacency(lm, adj_index0);
      next0 = adj0->lookup_next_index;

      ip0 = vlib_buffer_get_current (b0);
      hbh0 = (ip6_hop_by_hop_header_t *)(ip0+1);
      opt0 = (ip6_hop_by_hop_option_t *)(hbh0+1);
      limit0 = (ip6_hop_by_hop_option_t *)((u8 *)hbh0 + ((hbh0->length + 1) << 3));

      /*
       * Basic validity checks
       */
      if ((hbh0->length + 1) << 3 > clib_net_to_host_u16(ip0->payload_length)) {
        error0 = IP6_HOP_BY_HOP_ERROR_FORMAT;
        next0 = IP_LOOKUP_NEXT_DROP;
        goto out0;
      }

      /* Scan the set of h-b-h options, process ones that we understand */
      error0 = ip6_scan_hbh_options(b0, ip0, hbh0, opt0, limit0, &next0);

    out0:
      /* Has the classifier flagged this buffer for special treatment? */
    if (PREDICT_FALSE((error0 == 0) && (vnet_buffer(b0)->l2_classify.opaque_index & OI_DECAP)))
        next0 = hm->next_override;

      if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED)) {
        ip6_hop_by_hop_trace_t *t = vlib_add_trace(vm, node, b0, sizeof (*t));
        u32 trace_len = (hbh0->length + 1) << 3;
        t->next_index = next0;
        /* Capture the h-b-h option verbatim */
        trace_len = trace_len < ARRAY_LEN(t->option_data) ? trace_len : ARRAY_LEN(t->option_data);
        t->trace_len = trace_len;
        clib_memcpy(t->option_data, hbh0, trace_len);
      }

      b0->error = error_node->errors[error0];

      /* verify speculative enqueue, maybe switch current next frame */
      vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, bi0, next0);
    }
    vlib_put_next_frame (vm, node, next_index, n_left_to_next);
  }
  return frame->n_vectors;
}

VLIB_REGISTER_NODE (ip6_hop_by_hop_node) = {
  .function = ip6_hop_by_hop,
  .name = "ip6-hop-by-hop",
  .sibling_of = "ip6-lookup",
  .vector_size = sizeof (u32),
  .format_trace = format_ip6_hop_by_hop_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(ip6_hop_by_hop_error_strings),
  .error_strings = ip6_hop_by_hop_error_strings,
  .n_next_nodes = 0,
};

VLIB_NODE_FUNCTION_MULTIARCH (ip6_hop_by_hop_node, ip6_hop_by_hop);

static clib_error_t *
ip6_hop_by_hop_init (vlib_main_t * vm)
{
  ip6_hop_by_hop_main_t * hm = &ip6_hop_by_hop_main;
  memset(hm->options, 0, sizeof(hm->options));
  memset(hm->trace, 0, sizeof(hm->trace));
  hm->next_override = IP6_LOOKUP_NEXT_POP_HOP_BY_HOP;
  return (0);
}

VLIB_INIT_FUNCTION (ip6_hop_by_hop_init);

void ip6_hbh_set_next_override (uword next)
{
  ip6_hop_by_hop_main_t * hm = &ip6_hop_by_hop_main;

  hm->next_override = next;
}

int
ip6_hbh_register_option (u8 option,
                         int options(vlib_buffer_t *b, ip6_header_t *ip, ip6_hop_by_hop_option_t *opt),
                         u8 *trace(u8 *s, ip6_hop_by_hop_option_t *opt))
{
  ip6_main_t * im = &ip6_main;
  ip6_hop_by_hop_main_t * hm = &ip6_hop_by_hop_main;

  ASSERT (option < ARRAY_LEN (hm->options));

  /* Already registered */
  if (hm->options[option])
    return (-1);

  hm->options[option] = options;
  hm->trace[option] = trace;

  /* Set global variable */
  im->hbh_enabled = 1;

  return (0);
}

int
ip6_hbh_unregister_option (u8 option)
{
  ip6_main_t * im = &ip6_main;
  ip6_hop_by_hop_main_t * hm = &ip6_hop_by_hop_main;

  ASSERT (option < ARRAY_LEN (hm->options));

  /* Not registered */
  if (!hm->options[option])
    return (-1);

  hm->options[option] = NULL;
  hm->trace[option] = NULL;

  /* Disable global knob if this was the last option configured */
  int i;
  bool found = false;
  for (i = 0; i < 256; i++) {
    if (hm->options[option]) {
      found = true;
      break;
    }
  }
  if (!found)
    im->hbh_enabled = 0;

  return (0);
}

/* Global IP6 main. */
ip6_main_t ip6_main;

static clib_error_t *
ip6_lookup_init (vlib_main_t * vm)
{
  ip6_main_t * im = &ip6_main;
  clib_error_t * error;
  uword i;

  for (i = 0; i < ARRAY_LEN (im->fib_masks); i++)
    {
      u32 j, i0, i1;

      i0 = i / 32;
      i1 = i % 32;

      for (j = 0; j < i0; j++)
        im->fib_masks[i].as_u32[j] = ~0;

      if (i1)
        im->fib_masks[i].as_u32[i0] = clib_host_to_net_u32 (pow2_mask (i1) << (32 - i1));
    }

  ip_lookup_init (&im->lookup_main, /* is_ip6 */ 1);

  if (im->lookup_table_nbuckets == 0)
    im->lookup_table_nbuckets = IP6_FIB_DEFAULT_HASH_NUM_BUCKETS;

  im->lookup_table_nbuckets = 1<< max_log2 (im->lookup_table_nbuckets);

  if (im->lookup_table_size == 0)
    im->lookup_table_size = IP6_FIB_DEFAULT_HASH_MEMORY_SIZE;

  BV(clib_bihash_init) (&(im->ip6_table[IP6_FIB_TABLE_FWDING].ip6_hash),
                        "ip6 FIB fwding table",
                        im->lookup_table_nbuckets,
                        im->lookup_table_size);
  BV(clib_bihash_init) (&im->ip6_table[IP6_FIB_TABLE_NON_FWDING].ip6_hash,
                        "ip6 FIB non-fwding table",
                        im->lookup_table_nbuckets,
                        im->lookup_table_size);

  /* Create FIB with index 0 and table id of 0. */
  fib_table_find_or_create_and_lock(FIB_PROTOCOL_IP6, 0);

  {
    pg_node_t * pn;
    pn = pg_get_node (ip6_lookup_node.index);
    pn->unformat_edit = unformat_pg_ip6_header;
  }

  /* Unless explicitly configured, don't process HBH options */
  im->hbh_enabled = 0;

  {
    icmp6_neighbor_solicitation_header_t p;

    memset (&p, 0, sizeof (p));

    p.ip.ip_version_traffic_class_and_flow_label = clib_host_to_net_u32 (0x6 << 28);
    p.ip.payload_length = clib_host_to_net_u16 (sizeof (p)
                                                - STRUCT_OFFSET_OF (icmp6_neighbor_solicitation_header_t, neighbor));
    p.ip.protocol = IP_PROTOCOL_ICMP6;
    p.ip.hop_limit = 255;
    ip6_set_solicited_node_multicast_address (&p.ip.dst_address, 0);

    p.neighbor.icmp.type = ICMP6_neighbor_solicitation;

    p.link_layer_option.header.type = ICMP6_NEIGHBOR_DISCOVERY_OPTION_source_link_layer_address;
    p.link_layer_option.header.n_data_u64s = sizeof (p.link_layer_option) / sizeof (u64);

    vlib_packet_template_init (vm,
                               &im->discover_neighbor_packet_template,
                               &p, sizeof (p),
                               /* alloc chunk size */ 8,
                               "ip6 neighbor discovery");
  }

  error = ip6_feature_init (vm, im);

  return error;
}

VLIB_INIT_FUNCTION (ip6_lookup_init);

static clib_error_t *
add_del_ip6_interface_table (vlib_main_t * vm,
                             unformat_input_t * input,
                             vlib_cli_command_t * cmd)
{
  vnet_main_t * vnm = vnet_get_main();
  clib_error_t * error = 0;
  u32 sw_if_index, table_id;

  sw_if_index = ~0;

  if (! unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
    {
      error = clib_error_return (0, "unknown interface `%U'",
                                 format_unformat_error, input);
      goto done;
    }

  if (unformat (input, "%d", &table_id))
    ;
  else
    {
      error = clib_error_return (0, "expected table id `%U'",
                                 format_unformat_error, input);
      goto done;
    }

  {
    u32 fib_index = fib_table_find_or_create_and_lock(FIB_PROTOCOL_IP6,
                                                      table_id);

    vec_validate (ip6_main.fib_index_by_sw_if_index, sw_if_index);
    ip6_main.fib_index_by_sw_if_index[sw_if_index] = fib_index;
  }


 done:
  return error;
}

/*?
 * Place the indicated interface into the supplied IPv6 FIB table (also known
 * as a VRF). If the FIB table does not exist, this command creates it. To
 * display the current IPv6 FIB table, use the command '<em>show ip6 fib</em>'.
 * FIB table will only be displayed if a route has been added to the table, or
 * an IP Address is assigned to an interface in the table (which adds a route
 * automatically).
 *
 * @note IP addresses added after setting the interface IP table end up in
 * the indicated FIB table. If the IP address is added prior to adding the
 * interface to the FIB table, it will NOT be part of the FIB table. Predictable
 * but potentially counter-intuitive results occur if you provision interface
 * addresses in multiple FIBs. Upon RX, packets will be processed in the last
 * IP table ID provisioned. It might be marginally useful to evade source RPF
 * drops to put an interface address into multiple FIBs.
 *
 * @cliexpar
 * Example of how to add an interface to an IPv6 FIB table (where 2 is the table-id):
 * @cliexcmd{set interface ip6 table GigabitEthernet2/0/0 2}
 ?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (set_interface_ip6_table_command, static) = {
  .path = "set interface ip6 table",
  .function = add_del_ip6_interface_table,
  .short_help = "set interface ip6 table <interface> <table-id>"
};
/* *INDENT-ON* */

void
ip6_link_local_address_from_ethernet_mac_address (ip6_address_t *ip,
                                                  u8 *mac)
{
  ip->as_u64[0] = clib_host_to_net_u64 (0xFE80000000000000ULL);
  /* Invert the "u" bit */
  ip->as_u8 [8] = mac[0] ^ (1<<1);
  ip->as_u8 [9] = mac[1];
  ip->as_u8 [10] = mac[2];
  ip->as_u8 [11] = 0xFF;
  ip->as_u8 [12] = 0xFE;
  ip->as_u8 [13] = mac[3];
  ip->as_u8 [14] = mac[4];
  ip->as_u8 [15] = mac[5];
}

void
ip6_ethernet_mac_address_from_link_local_address (u8 *mac,
                                                  ip6_address_t *ip)
{
  /* Invert the previously inverted "u" bit */
  mac[0] = ip->as_u8 [8] ^ (1<<1);
  mac[1] = ip->as_u8 [9];
  mac[2] = ip->as_u8 [10];
  mac[3] = ip->as_u8 [13];
  mac[4] = ip->as_u8 [14];
  mac[5] = ip->as_u8 [15];
}

static clib_error_t *
test_ip6_link_command_fn (vlib_main_t * vm,
                          unformat_input_t * input,
                          vlib_cli_command_t * cmd)
{
  u8 mac[6];
  ip6_address_t _a, *a = &_a;

  if (unformat (input, "%U", unformat_ethernet_address, mac))
    {
      ip6_link_local_address_from_ethernet_mac_address (a, mac);
      vlib_cli_output (vm, "Link local address: %U",
                       format_ip6_address, a);
      ip6_ethernet_mac_address_from_link_local_address (mac, a);
      vlib_cli_output (vm, "Original MAC address: %U",
                       format_ethernet_address, mac);
    }

  return 0;
}

/*?
 * This command converts the given MAC Address into an IPv6 link-local
 * address.
 *
 * @cliexpar
 * Example of how to create an IPv6 link-local address:
 * @cliexstart{test ip6 link 16:d9:e0:91:79:86}
 * Link local address: fe80::14d9:e0ff:fe91:7986
 * Original MAC address: 16:d9:e0:91:79:86
 * @cliexend
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (test_link_command, static) = {
  .path = "test ip6 link",
  .function = test_ip6_link_command_fn,
  .short_help = "test ip6 link <mac-address>",
};
/* *INDENT-ON* */

int vnet_set_ip6_flow_hash (u32 table_id, u32 flow_hash_config)
{
  ip6_main_t * im6 = &ip6_main;
  ip6_fib_t * fib;
  uword * p = hash_get (im6->fib_index_by_table_id, table_id);

  if (p == 0)
    return -1;

  fib = ip6_fib_get (p[0]);

  fib->flow_hash_config = flow_hash_config;
  return 1;
}

static clib_error_t *
set_ip6_flow_hash_command_fn (vlib_main_t * vm,
                              unformat_input_t * input,
                              vlib_cli_command_t * cmd)
{
  int matched = 0;
  u32 table_id = 0;
  u32 flow_hash_config = 0;
  int rv;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) {
    if (unformat (input, "table %d", &table_id))
      matched = 1;
#define _(a,v) \
    else if (unformat (input, #a)) { flow_hash_config |= v; matched=1;}
    foreach_flow_hash_bit
#undef _
    else break;
  }

  if (matched == 0)
    return clib_error_return (0, "unknown input `%U'",
                              format_unformat_error, input);

  rv = vnet_set_ip6_flow_hash (table_id, flow_hash_config);
  switch (rv)
    {
    case 1:
      break;

    case -1:
      return clib_error_return (0, "no such FIB table %d", table_id);

    default:
      clib_warning ("BUG: illegal flow hash config 0x%x", flow_hash_config);
      break;
    }

  return 0;
}

/*?
 * Configure the set of IPv6 fields used by the flow hash.
 *
 * @cliexpar
 * @parblock
 * Example of how to set the flow hash on a given table:
 * @cliexcmd{set ip6 flow-hash table 8 dst sport dport proto}
 *
 * Example of display the configured flow hash:
 * @cliexstart{show ip6 fib}
 * ipv6-VRF:0, fib_index 0, flow hash: src dst sport dport proto
 * @::/0
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:5 buckets:1 uRPF:5 to:[0:0]]
 *     [0] [@0]: dpo-drop ip6
 * fe80::/10
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:10 buckets:1 uRPF:10 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * ff02::1/128
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:8 buckets:1 uRPF:8 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * ff02::2/128
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:7 buckets:1 uRPF:7 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * ff02::16/128
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:9 buckets:1 uRPF:9 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * ff02::1:ff00:0/104
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:6 buckets:1 uRPF:6 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * ipv6-VRF:8, fib_index 1, flow hash: dst sport dport proto
 * @::/0
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:21 buckets:1 uRPF:20 to:[0:0]]
 *     [0] [@0]: dpo-drop ip6
 * @::a:1:1:0:4/126
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:27 buckets:1 uRPF:26 to:[0:0]]
 *     [0] [@4]: ipv6-glean: af_packet0
 * @::a:1:1:0:7/128
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:28 buckets:1 uRPF:27 to:[0:0]]
 *     [0] [@2]: dpo-receive: @::a:1:1:0:7 on af_packet0
 * fe80::/10
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:26 buckets:1 uRPF:25 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * fe80::fe:3eff:fe3e:9222/128
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:29 buckets:1 uRPF:28 to:[0:0]]
 *     [0] [@2]: dpo-receive: fe80::fe:3eff:fe3e:9222 on af_packet0
 * ff02::1/128
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:24 buckets:1 uRPF:23 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * ff02::2/128
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:23 buckets:1 uRPF:22 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * ff02::16/128
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:25 buckets:1 uRPF:24 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * ff02::1:ff00:0/104
 *   unicast-ip6-chain
 *   [@0]: dpo-load-balance: [index:22 buckets:1 uRPF:21 to:[0:0]]
 *     [0] [@2]: dpo-receive
 * @cliexend
 * @endparblock
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (set_ip6_flow_hash_command, static) = {
    .path = "set ip6 flow-hash",
    .short_help =
    "set ip6 flow-hash table <table-id> [src] [dst] [sport] [dport] [proto] [reverse]",
    .function = set_ip6_flow_hash_command_fn,
};
/* *INDENT-ON* */

static clib_error_t *
show_ip6_local_command_fn (vlib_main_t * vm,
                           unformat_input_t * input,
                           vlib_cli_command_t * cmd)
{
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t * lm = &im->lookup_main;
  int i;

  vlib_cli_output (vm, "Protocols handled by ip6_local");
  for (i = 0; i < ARRAY_LEN(lm->local_next_by_ip_protocol); i++)
    {
      if (lm->local_next_by_ip_protocol[i] != IP_LOCAL_NEXT_PUNT)
        vlib_cli_output (vm, "%d", i);
    }
  return 0;
}



/*?
 * Display the set of protocols handled by the local IPv6 stack.
 *
 * @cliexpar
 * Example of how to display local protocol table:
 * @cliexstart{show ip6 local}
 * Protocols handled by ip6_local
 * 17
 * 43
 * 58
 * 115
 * @cliexend
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (show_ip6_local, static) = {
  .path = "show ip6 local",
  .function = show_ip6_local_command_fn,
  .short_help = "show ip6 local",
};
/* *INDENT-ON* */

int vnet_set_ip6_classify_intfc (vlib_main_t * vm, u32 sw_if_index,
                                 u32 table_index)
{
  vnet_main_t * vnm = vnet_get_main();
  vnet_interface_main_t * im = &vnm->interface_main;
  ip6_main_t * ipm = &ip6_main;
  ip_lookup_main_t * lm = &ipm->lookup_main;
  vnet_classify_main_t * cm = &vnet_classify_main;
  ip6_address_t *if_addr;

  if (pool_is_free_index (im->sw_interfaces, sw_if_index))
    return VNET_API_ERROR_NO_MATCHING_INTERFACE;

  if (table_index != ~0 && pool_is_free_index (cm->tables, table_index))
    return VNET_API_ERROR_NO_SUCH_ENTRY;

  vec_validate (lm->classify_table_index_by_sw_if_index, sw_if_index);
  lm->classify_table_index_by_sw_if_index [sw_if_index] = table_index;

  if_addr = ip6_interface_first_address (ipm, sw_if_index, NULL);

  if (NULL != if_addr)
  {
      fib_prefix_t pfx = {
          .fp_len = 128,
          .fp_proto = FIB_PROTOCOL_IP6,
          .fp_addr.ip6 = *if_addr,
      };
      u32 fib_index;

      fib_index = fib_table_get_index_for_sw_if_index(FIB_PROTOCOL_IP4,
                                                      sw_if_index);


      if (table_index != (u32) ~0)
      {
          dpo_id_t dpo = DPO_INVALID;

          dpo_set(&dpo,
                  DPO_CLASSIFY,
                  DPO_PROTO_IP6,
                  classify_dpo_create(DPO_PROTO_IP6,
                                      table_index));

          fib_table_entry_special_dpo_add(fib_index,
                                          &pfx,
                                          FIB_SOURCE_CLASSIFY,
                                          FIB_ENTRY_FLAG_NONE,
                                          &dpo);
          dpo_reset(&dpo);
      }
      else
      {
          fib_table_entry_special_remove(fib_index,
                                         &pfx,
                                         FIB_SOURCE_CLASSIFY);
      }
  }

  return 0;
}

static clib_error_t *
set_ip6_classify_command_fn (vlib_main_t * vm,
                             unformat_input_t * input,
                             vlib_cli_command_t * cmd)
{
  u32 table_index = ~0;
  int table_index_set = 0;
  u32 sw_if_index = ~0;
  int rv;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) {
    if (unformat (input, "table-index %d", &table_index))
      table_index_set = 1;
    else if (unformat (input, "intfc %U", unformat_vnet_sw_interface,
                       vnet_get_main(), &sw_if_index))
        ;
    else
        break;
  }

  if (table_index_set == 0)
      return clib_error_return (0, "classify table-index must be specified");

  if (sw_if_index == ~0)
    return clib_error_return (0, "interface / subif must be specified");

  rv = vnet_set_ip6_classify_intfc (vm, sw_if_index, table_index);

  switch (rv)
    {
    case 0:
      break;

    case VNET_API_ERROR_NO_MATCHING_INTERFACE:
      return clib_error_return (0, "No such interface");

    case VNET_API_ERROR_NO_SUCH_ENTRY:
      return clib_error_return (0, "No such classifier table");
    }
  return 0;
}

/*?
 * Assign a classification table to an interface. The classification
 * table is created using the '<em>classify table</em>' and '<em>classify session</em>'
 * commands. Once the table is create, use this command to filter packets
 * on an interface.
 *
 * @cliexpar
 * Example of how to assign a classification table to an interface:
 * @cliexcmd{set ip6 classify intfc GigabitEthernet2/0/0 table-index 1}
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (set_ip6_classify_command, static) = {
    .path = "set ip6 classify",
    .short_help =
    "set ip6 classify intfc <interface> table-index <classify-idx>",
    .function = set_ip6_classify_command_fn,
};
/* *INDENT-ON* */

static clib_error_t *
ip6_config (vlib_main_t * vm, unformat_input_t * input)
{
  ip6_main_t * im = &ip6_main;
  uword heapsize = 0;
  u32 tmp;
  u32 nbuckets = 0;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) {
    if (unformat (input, "hash-buckets %d", &tmp))
      nbuckets = tmp;
    else if (unformat (input, "heap-size %dm", &tmp))
      heapsize = ((u64)tmp) << 20;
    else if (unformat (input, "heap-size %dM", &tmp))
      heapsize = ((u64)tmp) << 20;
    else if (unformat (input, "heap-size %dg", &tmp))
      heapsize = ((u64)tmp) << 30;
    else if (unformat (input, "heap-size %dG", &tmp))
      heapsize = ((u64)tmp) << 30;
    else
      return clib_error_return (0, "unknown input '%U'",
                                format_unformat_error, input);
  }

  im->lookup_table_nbuckets = nbuckets;
  im->lookup_table_size = heapsize;

  return 0;
}

VLIB_EARLY_CONFIG_FUNCTION (ip6_config, "ip6");

#define TEST_CODE 1
#if TEST_CODE > 0

static clib_error_t *
set_interface_ip6_output_feature_command_fn (vlib_main_t * vm,
                                             unformat_input_t * input,
                                             vlib_cli_command_t * cmd)
{
  vnet_main_t * vnm = vnet_get_main();
  u32 sw_if_index = ~0;
  int is_add = 1;
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t * lm = &im->lookup_main;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "%U", unformat_vnet_sw_interface, vnm, &sw_if_index))
        ;
      else if (unformat (input, "del"))
        is_add = 0;
      else
        break;
    }

  if (sw_if_index == ~0)
    return clib_error_return (0, "unknown interface `%U'",
                              format_unformat_error, input);

  lm->tx_sw_if_has_ip_output_features =
    clib_bitmap_set (lm->tx_sw_if_has_ip_output_features, sw_if_index, is_add);

  return 0;
}

/*?
 * Enable or disable the output feature on an interface.
 *
 * @todo Need a more detailed description.
 *
 * @cliexpar
 * Example of how to enable the output feature on an interface:
 * @cliexcmd{set interface ip6 output feature GigabitEthernet2/0/0}
 * Example of how to disable the output feature on an interface:
 * @cliexcmd{set interface ip6 output feature GigabitEthernet2/0/0 del}
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (set_interface_ip6_output_feature, static) = {
  .path = "set interface ip6 output feature",
  .function = set_interface_ip6_output_feature_command_fn,
  .short_help = "set interface ip6 output feature <interface> [del]",
};
/* *INDENT-ON* */

#endif /* TEST_CODE */