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/ip/ip_frag.h>
#include <vnet/ip/ip6_neighbor.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_urpf_list.h>     /* for FIB uRPF check */
#include <vnet/fib/ip6_fib.h>
#include <vnet/mfib/ip6_mfib.h>
#include <vnet/dpo/load_balance_map.h>
#include <vnet/dpo/classify_dpo.h>

#ifndef CLIB_MARCH_VARIANT
#include <vppinfra/bihash_template.c>
#endif
#include <vnet/ip/ip6_forward.h>
#include <vnet/interface_output.h>

/* Flag used by IOAM code. Classifier sets it pop-hop-by-hop checks it */
#define OI_DECAP   0x80000000

static void
ip6_add_interface_prefix_routes (ip6_main_t * im,
                                 u32 sw_if_index,
                                 u32 fib_index,
                                 ip6_address_t * address, u32 address_length)
{
  ip_lookup_main_t *lm = &im->lookup_main;
  ip_interface_prefix_t *if_prefix;

  /* *INDENT-OFF* */
  ip_interface_prefix_key_t key = {
    .prefix = {
      .fp_len = address_length,
      .fp_proto = FIB_PROTOCOL_IP6,
      .fp_addr.ip6 = {
        .as_u64 = {
          address->as_u64[0] & im->fib_masks[address_length].as_u64[0],
          address->as_u64[1] & im->fib_masks[address_length].as_u64[1],
        },
      },
    },
    .sw_if_index = sw_if_index,
  };
  /* *INDENT-ON* */

  /* If prefix already set on interface, just increment ref count & return */
  if_prefix = ip_get_interface_prefix (lm, &key);
  if (if_prefix)
    {
      if_prefix->ref_count += 1;
      return;
    }

  /* New prefix - allocate a pool entry, initialize it, add to the hash */
  pool_get (lm->if_prefix_pool, if_prefix);
  if_prefix->ref_count = 1;
  clib_memcpy (&if_prefix->key, &key, sizeof (key));
  mhash_set (&lm->prefix_to_if_prefix_index, &key,
             if_prefix - lm->if_prefix_pool, 0 /* old value */ );

  /* length < 128 - add glean */
  if (address_length < 128)
    {
      /* set the glean route for the prefix */
      fib_table_entry_update_one_path (fib_index, &key.prefix,
                                       FIB_SOURCE_INTERFACE,
                                       (FIB_ENTRY_FLAG_CONNECTED |
                                        FIB_ENTRY_FLAG_ATTACHED),
                                       DPO_PROTO_IP6,
                                       /* No next-hop address */
                                       NULL, sw_if_index,
                                       /* invalid FIB index */
                                       ~0, 1,
                                       /* no out-label stack */
                                       NULL, FIB_ROUTE_PATH_FLAG_NONE);
    }
}

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,
  };

  /* set special routes for the prefix if needed */
  ip6_add_interface_prefix_routes (im, sw_if_index, fib_index,
                                   address, a->address_length);

  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),
                                   DPO_PROTO_IP6,
                                   &pfx.fp_addr,
                                   sw_if_index, ~0,
                                   1, NULL, FIB_ROUTE_PATH_FLAG_NONE);
}

static void
ip6_del_interface_prefix_routes (ip6_main_t * im,
                                 u32 sw_if_index,
                                 u32 fib_index,
                                 ip6_address_t * address, u32 address_length)
{
  ip_lookup_main_t *lm = &im->lookup_main;
  ip_interface_prefix_t *if_prefix;

  /* *INDENT-OFF* */
  ip_interface_prefix_key_t key = {
    .prefix = {
      .fp_len = address_length,
      .fp_proto = FIB_PROTOCOL_IP6,
      .fp_addr.ip6 = {
        .as_u64 = {
          address->as_u64[0] & im->fib_masks[address_length].as_u64[0],
          address->as_u64[1] & im->fib_masks[address_length].as_u64[1],
        },
      },
    },
    .sw_if_index = sw_if_index,
  };
  /* *INDENT-ON* */

  if_prefix = ip_get_interface_prefix (lm, &key);
  if (!if_prefix)
    {
      clib_warning ("Prefix not found while deleting %U",
                    format_ip4_address_and_length, address, address_length);
      return;
    }

  /* If not deleting last intf addr in prefix, decrement ref count & return */
  if_prefix->ref_count -= 1;
  if (if_prefix->ref_count > 0)
    return;

  /* length <= 128, delete glean route */
  if (address_length <= 128)
    {
      /* remove glean route for prefix */
      fib_table_entry_delete (fib_index, &key.prefix, FIB_SOURCE_INTERFACE);
    }

  mhash_unset (&lm->prefix_to_if_prefix_index, &key, 0 /* old_value */ );
  pool_put (lm->if_prefix_pool, if_prefix);
}

static void
ip6_del_interface_routes (u32 sw_if_index, ip6_main_t * im,
                          u32 fib_index,
                          ip6_address_t * address, u32 address_length)
{
  fib_prefix_t pfx = {
    .fp_len = 128,
    .fp_proto = FIB_PROTOCOL_IP6,
    .fp_addr.ip6 = *address,
  };

  /* delete special routes for the prefix if needed */
  ip6_del_interface_prefix_routes (im, sw_if_index, fib_index,
                                   address, address_length);

  fib_table_entry_delete (fib_index, &pfx, FIB_SOURCE_INTERFACE);
}

#ifndef CLIB_MARCH_VARIANT
void
ip6_sw_interface_enable_disable (u32 sw_if_index, u32 is_enable)
{
  ip6_main_t *im = &ip6_main;

  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
    {
      /* The ref count is 0 when an address is removed from an interface that has
       * no address - this is not a ciritical error */
      if (0 == im->ip_enabled_by_sw_if_index[sw_if_index] ||
          0 != --im->ip_enabled_by_sw_if_index[sw_if_index])
        return;
    }

  vnet_feature_enable_disable ("ip6-unicast", "ip6-not-enabled", sw_if_index,
                               !is_enable, 0, 0);

  vnet_feature_enable_disable ("ip6-multicast", "ip6-not-enabled",
                               sw_if_index, !is_enable, 0, 0);
}

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

  /* *INDENT-OFF* */
  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;
  }));
  /* *INDENT-ON* */
  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;
  ip6_address_t ll_addr;

  /* local0 interface doesn't support IP addressing */
  if (sw_if_index == 0)
    {
      return
        clib_error_create ("local0 interface doesn't support IP addressing");
    }

  if (ip6_address_is_link_local_unicast (address))
    {
      if (address_length != 128)
        {
          vnm->api_errno = VNET_API_ERROR_ADDRESS_LENGTH_MISMATCH;
          return
            clib_error_create
            ("prefix length of link-local address must be 128");
        }
      if (!is_del)
        {
          return ip6_neighbor_set_link_local_address (vm, sw_if_index,
                                                      address);
        }
      else
        {
          ll_addr = ip6_neighbor_get_link_local_address (sw_if_index);
          if (ip6_address_is_equal (&ll_addr, address))
            {
              vnm->api_errno = VNET_API_ERROR_ADDRESS_NOT_DELETABLE;
              return clib_error_create ("address not deletable");
            }
          else
            {
              vnm->api_errno = VNET_API_ERROR_ADDRESS_NOT_FOUND_FOR_INTERFACE;
              return clib_error_create ("address not found");
            }
        }
    }

  vec_validate (im->fib_index_by_sw_if_index, sw_if_index);
  vec_validate (im->mfib_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);

  /* *INDENT-OFF* */
  if (!is_del)
    {
      /* When adding an address check that it does not conflict
         with an existing address on any interface in this table. */
      ip_interface_address_t *ia;
      vnet_sw_interface_t *sif;

      pool_foreach(sif, vnm->interface_main.sw_interfaces,
      ({
          if (im->fib_index_by_sw_if_index[sw_if_index] ==
              im->fib_index_by_sw_if_index[sif->sw_if_index])
            {
              foreach_ip_interface_address
                (&im->lookup_main, ia, sif->sw_if_index,
                 0 /* honor unnumbered */ ,
                 ({
                   ip6_address_t * x =
                     ip_interface_address_get_address
                     (&im->lookup_main, ia);
                   if (ip6_destination_matches_route
                       (im, address, x, ia->address_length) ||
                       ip6_destination_matches_route (im,
                                                      x,
                                                      address,
                                                      address_length))
                     {
                       /* an intf may have >1 addr from the same prefix */
                       if ((sw_if_index == sif->sw_if_index) &&
                           (ia->address_length == address_length) &&
                           !ip6_address_is_equal (x, address))
                         continue;

                       /* error if the length or intf was different */
                       vnm->api_errno = VNET_API_ERROR_DUPLICATE_IF_ADDRESS;
                       return
                         clib_error_create
                         ("failed to add %U which conflicts with %U for interface %U",
                          format_ip6_address_and_length, address,
                          address_length,
                          format_ip6_address_and_length, x,
                          ia->address_length,
                          format_vnet_sw_if_index_name, vnm,
                          sif->sw_if_index);
                     }
                 }));
            }
      }));
    }
  /* *INDENT-ON* */

  {
    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;
  }

  ip6_sw_interface_enable_disable (sw_if_index, !is_del);

  /* intf addr routes are added/deleted on admin up/down */
  if (vnet_sw_interface_is_admin_up (vnm, sw_if_index))
    {
      if (is_del)
        ip6_del_interface_routes (sw_if_index,
                                  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;
}

#endif

static 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);

  /* *INDENT-OFF* */
  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 (sw_if_index, im, fib_index,
                                a, ia->address_length);
  }));
  /* *INDENT-ON* */

  return 0;
}

VNET_SW_INTERFACE_ADMIN_UP_DOWN_FUNCTION (ip6_sw_interface_admin_up_down);

/* Built-in ip6 unicast rx feature path definition */
/* *INDENT-OFF* */
VNET_FEATURE_ARC_INIT (ip6_unicast, static) =
{
  .arc_name  = "ip6-unicast",
  .start_nodes = VNET_FEATURES ("ip6-input"),
  .last_in_arc = "ip6-lookup",
  .arc_index_ptr = &ip6_main.lookup_main.ucast_feature_arc_index,
};

VNET_FEATURE_INIT (ip6_flow_classify, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "ip6-flow-classify",
  .runs_before = VNET_FEATURES ("ip6-inacl"),
};

VNET_FEATURE_INIT (ip6_inacl, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "ip6-inacl",
  .runs_before = VNET_FEATURES ("ip6-policer-classify"),
};

VNET_FEATURE_INIT (ip6_policer_classify, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "ip6-policer-classify",
  .runs_before = VNET_FEATURES ("ipsec6-input-feature"),
};

VNET_FEATURE_INIT (ip6_ipsec, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "ipsec6-input-feature",
  .runs_before = VNET_FEATURES ("l2tp-decap"),
};

VNET_FEATURE_INIT (ip6_l2tp, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "l2tp-decap",
  .runs_before = VNET_FEATURES ("vpath-input-ip6"),
};

VNET_FEATURE_INIT (ip6_vpath, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "vpath-input-ip6",
  .runs_before = VNET_FEATURES ("ip6-vxlan-bypass"),
};

VNET_FEATURE_INIT (ip6_vxlan_bypass, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "ip6-vxlan-bypass",
  .runs_before = VNET_FEATURES ("ip6-lookup"),
};

VNET_FEATURE_INIT (ip6_not_enabled, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "ip6-not-enabled",
  .runs_before = VNET_FEATURES ("ip6-lookup"),
};

VNET_FEATURE_INIT (ip6_lookup, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "ip6-lookup",
  .runs_before = 0,  /*last feature*/
};

/* Built-in ip6 multicast rx feature path definition (none now) */
VNET_FEATURE_ARC_INIT (ip6_multicast, static) =
{
  .arc_name  = "ip6-multicast",
  .start_nodes = VNET_FEATURES ("ip6-input"),
  .last_in_arc = "ip6-mfib-forward-lookup",
  .arc_index_ptr = &ip6_main.lookup_main.mcast_feature_arc_index,
};

VNET_FEATURE_INIT (ip6_vpath_mc, static) = {
  .arc_name = "ip6-multicast",
  .node_name = "vpath-input-ip6",
  .runs_before = VNET_FEATURES ("ip6-mfib-forward-lookup"),
};

VNET_FEATURE_INIT (ip6_not_enabled_mc, static) = {
  .arc_name = "ip6-multicast",
  .node_name = "ip6-not-enabled",
  .runs_before = VNET_FEATURES ("ip6-mfib-forward-lookup"),
};

VNET_FEATURE_INIT (ip6_mc_lookup, static) = {
  .arc_name = "ip6-multicast",
  .node_name = "ip6-mfib-forward-lookup",
  .runs_before = 0, /* last feature */
};

/* Built-in ip4 tx feature path definition */
VNET_FEATURE_ARC_INIT (ip6_output, static) =
{
  .arc_name  = "ip6-output",
  .start_nodes = VNET_FEATURES ("ip6-rewrite", "ip6-midchain", "ip6-dvr-dpo"),
  .last_in_arc = "interface-output",
  .arc_index_ptr = &ip6_main.lookup_main.output_feature_arc_index,
};

VNET_FEATURE_INIT (ip6_outacl, static) = {
  .arc_name = "ip6-output",
  .node_name = "ip6-outacl",
  .runs_before = VNET_FEATURES ("ipsec6-output-feature"),
};

VNET_FEATURE_INIT (ip6_ipsec_output, static) = {
  .arc_name = "ip6-output",
  .node_name = "ipsec6-output-feature",
  .runs_before = VNET_FEATURES ("interface-output"),
};

VNET_FEATURE_INIT (ip6_interface_output, static) = {
  .arc_name = "ip6-output",
  .node_name = "interface-output",
  .runs_before = 0, /* not before any other features */
};
/* *INDENT-ON* */

static clib_error_t *
ip6_sw_interface_add_del (vnet_main_t * vnm, u32 sw_if_index, u32 is_add)
{
  ip6_main_t *im = &ip6_main;

  vec_validate (im->fib_index_by_sw_if_index, sw_if_index);
  vec_validate (im->mfib_index_by_sw_if_index, sw_if_index);

  if (!is_add)
    {
      /* Ensure that IPv6 is disabled */
      ip6_main_t *im6 = &ip6_main;
      ip_lookup_main_t *lm6 = &im6->lookup_main;
      ip_interface_address_t *ia = 0;
      ip6_address_t *address;
      vlib_main_t *vm = vlib_get_main ();

      ip6_neighbor_sw_interface_add_del (vnm, sw_if_index, 0 /* is_add */ );
      vnet_sw_interface_update_unnumbered (sw_if_index, ~0, 0);
      /* *INDENT-OFF* */
      foreach_ip_interface_address (lm6, ia, sw_if_index, 0,
      ({
        address = ip_interface_address_get_address (lm6, ia);
        ip6_add_del_interface_address(vm, sw_if_index, address, ia->address_length, 1);
      }));
      /* *INDENT-ON* */
      ip6_mfib_interface_enable_disable (sw_if_index, 0);
    }

  vnet_feature_enable_disable ("ip6-unicast", "ip6-not-enabled", sw_if_index,
                               is_add, 0, 0);

  vnet_feature_enable_disable ("ip6-multicast", "ip6-not-enabled",
                               sw_if_index, is_add, 0, 0);

  return /* no error */ 0;
}

VNET_SW_INTERFACE_ADD_DEL_FUNCTION (ip6_sw_interface_add_del);

VLIB_NODE_FN (ip6_lookup_node) (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);

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ip6_lookup_node) =
{
  .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,
};
/* *INDENT-ON* */

VLIB_NODE_FN (ip6_load_balance_node) (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;
  u32 thread_index = vm->thread_index;
  ip6_main_t *im = &ip6_main;
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
  u16 nexts[VLIB_FRAME_SIZE], *next;

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

  vlib_get_buffers (vm, from, bufs, n_left);

  while (n_left >= 4)
    {
      const load_balance_t *lb0, *lb1;
      const ip6_header_t *ip0, *ip1;
      u32 lbi0, hc0, lbi1, hc1;
      const dpo_id_t *dpo0, *dpo1;

      /* Prefetch next iteration. */
      {
        vlib_prefetch_buffer_header (b[2], STORE);
        vlib_prefetch_buffer_header (b[3], STORE);

        CLIB_PREFETCH (b[2]->data, sizeof (ip0[0]), STORE);
        CLIB_PREFETCH (b[3]->data, sizeof (ip0[0]), STORE);
      }

      ip0 = vlib_buffer_get_current (b[0]);
      ip1 = vlib_buffer_get_current (b[1]);
      lbi0 = vnet_buffer (b[0])->ip.adj_index[VLIB_TX];
      lbi1 = vnet_buffer (b[1])->ip.adj_index[VLIB_TX];

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

      /*
       * this node is for via FIBs we can re-use the hash value from the
       * to node if present.
       * We don't want to use the same hash value at each level in the recursion
       * graph as that would lead to polarisation
       */
      hc0 = hc1 = 0;

      if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
        {
          if (PREDICT_TRUE (vnet_buffer (b[0])->ip.flow_hash))
            {
              hc0 = vnet_buffer (b[0])->ip.flow_hash =
                vnet_buffer (b[0])->ip.flow_hash >> 1;
            }
          else
            {
              hc0 = vnet_buffer (b[0])->ip.flow_hash =
                ip6_compute_flow_hash (ip0, lb0->lb_hash_config);
            }
          dpo0 = load_balance_get_fwd_bucket
            (lb0, (hc0 & (lb0->lb_n_buckets_minus_1)));
        }
      else
        {
          dpo0 = load_balance_get_bucket_i (lb0, 0);
        }
      if (PREDICT_FALSE (lb1->lb_n_buckets > 1))
        {
          if (PREDICT_TRUE (vnet_buffer (b[1])->ip.flow_hash))
            {
              hc1 = vnet_buffer (b[1])->ip.flow_hash =
                vnet_buffer (b[1])->ip.flow_hash >> 1;
            }
          else
            {
              hc1 = vnet_buffer (b[1])->ip.flow_hash =
                ip6_compute_flow_hash (ip1, lb1->lb_hash_config);
            }
          dpo1 = load_balance_get_fwd_bucket
            (lb1, (hc1 & (lb1->lb_n_buckets_minus_1)));
        }
      else
        {
          dpo1 = load_balance_get_bucket_i (lb1, 0);
        }

      next[0] = dpo0->dpoi_next_node;
      next[1] = 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))
        {
          next[0] = (dpo_is_adj (dpo0) && im->hbh_enabled) ?
            (ip_lookup_next_t) IP6_LOOKUP_NEXT_HOP_BY_HOP : next[0];
        }
      /* Only process the HBH Option Header if explicitly configured to do so */
      if (PREDICT_FALSE (ip1->protocol == IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS))
        {
          next[1] = (dpo_is_adj (dpo1) && im->hbh_enabled) ?
            (ip_lookup_next_t) IP6_LOOKUP_NEXT_HOP_BY_HOP : next[1];
        }

      vnet_buffer (b[0])->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
      vnet_buffer (b[1])->ip.adj_index[VLIB_TX] = dpo1->dpoi_index;

      vlib_increment_combined_counter
        (cm, thread_index, lbi0, 1, vlib_buffer_length_in_chain (vm, b[0]));
      vlib_increment_combined_counter
        (cm, thread_index, lbi1, 1, vlib_buffer_length_in_chain (vm, b[1]));

      b += 2;
      next += 2;
      n_left -= 2;
    }

  while (n_left > 0)
    {
      const load_balance_t *lb0;
      const ip6_header_t *ip0;
      const dpo_id_t *dpo0;
      u32 lbi0, hc0;

      ip0 = vlib_buffer_get_current (b[0]);
      lbi0 = vnet_buffer (b[0])->ip.adj_index[VLIB_TX];

      lb0 = load_balance_get (lbi0);

      hc0 = 0;
      if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
        {
          if (PREDICT_TRUE (vnet_buffer (b[0])->ip.flow_hash))
            {
              hc0 = vnet_buffer (b[0])->ip.flow_hash =
                vnet_buffer (b[0])->ip.flow_hash >> 1;
            }
          else
            {
              hc0 = vnet_buffer (b[0])->ip.flow_hash =
                ip6_compute_flow_hash (ip0, lb0->lb_hash_config);
            }
          dpo0 = load_balance_get_fwd_bucket
            (lb0, (hc0 & (lb0->lb_n_buckets_minus_1)));
        }
      else
        {
          dpo0 = load_balance_get_bucket_i (lb0, 0);
        }

      next[0] = dpo0->dpoi_next_node;
      vnet_buffer (b[0])->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;

      /* Only process the HBH Option Header if explicitly configured to do so */
      if (PREDICT_FALSE (ip0->protocol == IP_PROTOCOL_IP6_HOP_BY_HOP_OPTIONS))
        {
          next[0] = (dpo_is_adj (dpo0) && im->hbh_enabled) ?
            (ip_lookup_next_t) IP6_LOOKUP_NEXT_HOP_BY_HOP : next[0];
        }

      vlib_increment_combined_counter
        (cm, thread_index, lbi0, 1, vlib_buffer_length_in_chain (vm, b[0]));

      b += 1;
      next += 1;
      n_left -= 1;
    }

  vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);

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

  return frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ip6_load_balance_node) =
{
  .name = "ip6-load-balance",
  .vector_size = sizeof (u32),
  .sibling_of = "ip6-lookup",
  .format_trace = format_ip6_lookup_trace,
};
/* *INDENT-ON* */

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;

#ifndef CLIB_MARCH_VARIANT
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 *);
  u32 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;
}
#endif

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 *);
  u32 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 *);
  u32 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,
              t->adj_index, t->packet_data, sizeof (t->packet_data));
  return s;
}

/* Common trace function for all ip6-forward next nodes. */
#ifndef CLIB_MARCH_VARIANT
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_fast (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_fast (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_fast (t0->packet_data,
                            vlib_buffer_get_current (b0),
                            sizeof (t0->packet_data));
        }
      from += 1;
      n_left -= 1;
    }
}

/* 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 payload_length_host_byte_order;
  u32 i;
  u32 headers_size = sizeof (ip0[0]);
  u8 *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 = (u8 *) (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)
   * or UDP-Ping 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)
              || (ext_hdr->next_hdr == IP_PROTOCOL_UDP));

      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;
    }

  if (p0)
    return ip_calculate_l4_checksum (vm, p0, sum0,
                                     payload_length_host_byte_order,
                                     (u8 *) ip0, headers_size, NULL);
  else
    return ip_calculate_l4_checksum (vm, 0, sum0,
                                     payload_length_host_byte_order, NULL, 0,
                                     data_this_buffer);
}

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 |= (VNET_BUFFER_F_L4_CHECKSUM_COMPUTED
                    | VNET_BUFFER_F_L4_CHECKSUM_CORRECT);
      return p0->flags;
    }

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

  p0->flags |= (VNET_BUFFER_F_L4_CHECKSUM_COMPUTED
                | ((sum16 == 0) << VNET_BUFFER_F_LOG2_L4_CHECKSUM_CORRECT));

  return p0->flags;
}
#endif

/**
 * @brief returns number of links on which src is reachable.
 */
always_inline int
ip6_urpf_loose_check (ip6_main_t * im, vlib_buffer_t * b, ip6_header_t * i)
{
  const load_balance_t *lb0;
  index_t lbi;
  u32 fib_index;

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

  lbi = ip6_fib_table_fwding_lookup (fib_index, &i->src_address);
  lb0 = load_balance_get (lbi);

  return (fib_urpf_check_size (lb0->lb_urpf));
}

always_inline u8
ip6_next_proto_is_tcp_udp (vlib_buffer_t * p0, ip6_header_t * ip0,
                           u32 * udp_offset0)
{
  u32 proto0;
  proto0 = ip6_locate_header (p0, ip0, IP_PROTOCOL_UDP, udp_offset0);
  if (proto0 != IP_PROTOCOL_UDP)
    {
      proto0 = ip6_locate_header (p0, ip0, IP_PROTOCOL_TCP, udp_offset0);
      proto0 = (proto0 == IP_PROTOCOL_TCP) ? proto0 : 0;
    }
  return proto0;
}

/* *INDENT-OFF* */
VNET_FEATURE_ARC_INIT (ip6_local) =
{
  .arc_name  = "ip6-local",
  .start_nodes = VNET_FEATURES ("ip6-local"),
};
/* *INDENT-ON* */

always_inline uword
ip6_local_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
                  vlib_frame_t * frame, int head_of_feature_arc)
{
  ip6_main_t *im = &ip6_main;
  ip_lookup_main_t *lm = &im->lookup_main;
  u32 *from, n_left_from;
  vlib_node_runtime_t *error_node =
    vlib_node_get_runtime (vm, ip6_input_node.index);
  u8 arc_index = vnet_feat_arc_ip6_local.feature_arc_index;
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
  u16 nexts[VLIB_FRAME_SIZE], *next;

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

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

  vlib_get_buffers (vm, from, bufs, n_left_from);
  b = bufs;
  next = nexts;

  while (n_left_from > 2)
    {
      /* Prefetch next iteration. */
      if (n_left_from >= 6)
        {
          vlib_prefetch_buffer_header (b[4], STORE);
          vlib_prefetch_buffer_header (b[5], STORE);
          vlib_prefetch_buffer_data (b[2], LOAD);
          vlib_prefetch_buffer_data (b[3], LOAD);
        }

      u8 error[2];
      error[0] = IP6_ERROR_UNKNOWN_PROTOCOL;
      error[1] = IP6_ERROR_UNKNOWN_PROTOCOL;

      ip6_header_t *ip[2];
      ip[0] = vlib_buffer_get_current (b[0]);
      ip[1] = vlib_buffer_get_current (b[1]);

      if (head_of_feature_arc)
        {
          vnet_buffer (b[0])->l3_hdr_offset = b[0]->current_data;
          vnet_buffer (b[1])->l3_hdr_offset = b[1]->current_data;

          u8 type[2];
          type[0] = lm->builtin_protocol_by_ip_protocol[ip[0]->protocol];
          type[1] = lm->builtin_protocol_by_ip_protocol[ip[1]->protocol];

          u32 flags[2];
          flags[0] = b[0]->flags;
          flags[1] = b[1]->flags;

          u32 good_l4_csum[2];
          good_l4_csum[0] =
            flags[0] & (VNET_BUFFER_F_L4_CHECKSUM_CORRECT |
                        VNET_BUFFER_F_OFFLOAD_TCP_CKSUM |
                        VNET_BUFFER_F_OFFLOAD_UDP_CKSUM);
          good_l4_csum[1] =
            flags[1] & (VNET_BUFFER_F_L4_CHECKSUM_CORRECT |
                        VNET_BUFFER_F_OFFLOAD_TCP_CKSUM |
                        VNET_BUFFER_F_OFFLOAD_UDP_CKSUM);

          u32 udp_offset[2] = { };
          u8 is_tcp_udp[2];
          is_tcp_udp[0] =
            ip6_next_proto_is_tcp_udp (b[0], ip[0], &udp_offset[0]);
          is_tcp_udp[1] =
            ip6_next_proto_is_tcp_udp (b[1], ip[1], &udp_offset[1]);
          i16 len_diff[2] = { 0 };
          if (PREDICT_TRUE (is_tcp_udp[0]))
            {
              udp_header_t *udp =
                (udp_header_t *) ((u8 *) ip[0] + udp_offset[0]);
              good_l4_csum[0] |= type[0] == IP_BUILTIN_PROTOCOL_UDP
                && udp->checksum == 0;
              /* optimistically verify UDP length. */
              u16 ip_len, udp_len;
              ip_len = clib_net_to_host_u16 (ip[0]->payload_length);
              udp_len = clib_net_to_host_u16 (udp->length);
              len_diff[0] = ip_len - udp_len;
            }
          if (PREDICT_TRUE (is_tcp_udp[1]))
            {
              udp_header_t *udp =
                (udp_header_t *) ((u8 *) ip[1] + udp_offset[1]);
              good_l4_csum[1] |= type[1] == IP_BUILTIN_PROTOCOL_UDP
                && udp->checksum == 0;
              /* optimistically verify UDP length. */
              u16 ip_len, udp_len;
              ip_len = clib_net_to_host_u16 (ip[1]->payload_length);
              udp_len = clib_net_to_host_u16 (udp->length);
              len_diff[1] = ip_len - udp_len;
            }

          good_l4_csum[0] |= type[0] == IP_BUILTIN_PROTOCOL_UNKNOWN;
          good_l4_csum[1] |= type[1] == IP_BUILTIN_PROTOCOL_UNKNOWN;

          len_diff[0] = type[0] == IP_BUILTIN_PROTOCOL_UDP ? len_diff[0] : 0;
          len_diff[1] = type[1] == IP_BUILTIN_PROTOCOL_UDP ? len_diff[1] : 0;

          u8 need_csum[2];
          need_csum[0] = type[0] != IP_BUILTIN_PROTOCOL_UNKNOWN
            && !good_l4_csum[0]
            && !(flags[0] & VNET_BUFFER_F_L4_CHECKSUM_COMPUTED);
          need_csum[1] = type[1] != IP_BUILTIN_PROTOCOL_UNKNOWN
            && !good_l4_csum[1]
            && !(flags[1] & VNET_BUFFER_F_L4_CHECKSUM_COMPUTED);
          if (PREDICT_FALSE (need_csum[0]))
            {
              flags[0] = ip6_tcp_udp_icmp_validate_checksum (vm, b[0]);
              good_l4_csum[0] = flags[0] & VNET_BUFFER_F_L4_CHECKSUM_CORRECT;
            }
          if (PREDICT_FALSE (need_csum[1]))
            {
              flags[1] = ip6_tcp_udp_icmp_validate_checksum (vm, b[1]);
              good_l4_csum[1] = flags[1] & VNET_BUFFER_F_L4_CHECKSUM_CORRECT;
            }

          error[0] = IP6_ERROR_UNKNOWN_PROTOCOL;
          error[0] = len_diff[0] < 0 ? IP6_ERROR_UDP_LENGTH : error[0];
          error[1] = IP6_ERROR_UNKNOWN_PROTOCOL;
          error[1] = len_diff[1] < 0 ? IP6_ERROR_UDP_LENGTH : error[1];

          STATIC_ASSERT (IP6_ERROR_UDP_CHECKSUM + IP_BUILTIN_PROTOCOL_UDP ==
                         IP6_ERROR_UDP_CHECKSUM,
                         "Wrong IP6 errors constants");
          STATIC_ASSERT (IP6_ERROR_UDP_CHECKSUM + IP_BUILTIN_PROTOCOL_ICMP ==
                         IP6_ERROR_ICMP_CHECKSUM,
                         "Wrong IP6 errors constants");

          error[0] =
            !good_l4_csum[0] ? IP6_ERROR_UDP_CHECKSUM + type[0] : error[0];
          error[1] =
            !good_l4_csum[1] ? IP6_ERROR_UDP_CHECKSUM + type[1] : error[1];

          /* Drop packets from unroutable hosts. */
          /* If this is a neighbor solicitation (ICMP), skip source RPF check */
          u8 unroutable[2];
          unroutable[0] = error[0] == IP6_ERROR_UNKNOWN_PROTOCOL
            && type[0] != IP_BUILTIN_PROTOCOL_ICMP
            && !ip6_address_is_link_local_unicast (&ip[0]->src_address);
          unroutable[1] = error[1] == IP6_ERROR_UNKNOWN_PROTOCOL
            && type[1] != IP_BUILTIN_PROTOCOL_ICMP
            && !ip6_address_is_link_local_unicast (&ip[1]->src_address);
          if (PREDICT_FALSE (unroutable[0]))
            {
              error[0] =
                !ip6_urpf_loose_check (im, b[0],
                                       ip[0]) ? IP6_ERROR_SRC_LOOKUP_MISS
                : error[0];
            }
          if (PREDICT_FALSE (unroutable[1]))
            {
              error[1] =
                !ip6_urpf_loose_check (im, b[1],
                                       ip[1]) ? IP6_ERROR_SRC_LOOKUP_MISS
                : error[1];
            }

          vnet_buffer (b[0])->ip.fib_index =
            vnet_buffer (b[0])->sw_if_index[VLIB_TX] != ~0 ?
            vnet_buffer (b[0])->sw_if_index[VLIB_TX] :
            vnet_buffer (b[0])->ip.fib_index;
          vnet_buffer (b[1])->ip.fib_index =
            vnet_buffer (b[1])->sw_if_index[VLIB_TX] != ~0 ?
            vnet_buffer (b[1])->sw_if_index[VLIB_TX] :
            vnet_buffer (b[1])->ip.fib_index;
        }                       /* head_of_feature_arc */

      next[0] = lm->local_next_by_ip_protocol[ip[0]->protocol];
      next[0] =
        error[0] != IP6_ERROR_UNKNOWN_PROTOCOL ? IP_LOCAL_NEXT_DROP : next[0];
      next[1] = lm->local_next_by_ip_protocol[ip[1]->protocol];
      next[1] =
        error[1] != IP6_ERROR_UNKNOWN_PROTOCOL ? IP_LOCAL_NEXT_DROP : next[1];

      b[0]->error = error_node->errors[0];
      b[1]->error = error_node->errors[1];

      if (head_of_feature_arc)
        {
          u8 ip6_unknown[2];
          ip6_unknown[0] = error[0] == (u8) IP6_ERROR_UNKNOWN_PROTOCOL;
          ip6_unknown[1] = error[1] == (u8) IP6_ERROR_UNKNOWN_PROTOCOL;
          if (PREDICT_TRUE (ip6_unknown[0]))
            {
              u32 next32 = next[0];
              vnet_feature_arc_start (arc_index,
                                      vnet_buffer (b[0])->sw_if_index
                                      [VLIB_RX], &next32, b[0]);
              next[0] = next32;
            }
          if (PREDICT_TRUE (ip6_unknown[1]))
            {
              u32 next32 = next[1];
              vnet_feature_arc_start (arc_index,
                                      vnet_buffer (b[1])->sw_if_index
                                      [VLIB_RX], &next32, b[1]);
              next[1] = next32;
            }
        }

      /* next */
      b += 2;
      next += 2;
      n_left_from -= 2;
    }

  while (n_left_from)
    {
      u8 error;
      error = IP6_ERROR_UNKNOWN_PROTOCOL;

      ip6_header_t *ip;
      ip = vlib_buffer_get_current (b[0]);

      if (head_of_feature_arc)
        {
          vnet_buffer (b[0])->l3_hdr_offset = b[0]->current_data;
          u8 type = lm->builtin_protocol_by_ip_protocol[ip->protocol];

          u32 flags = b[0]->flags;
          u32 good_l4_csum =
            flags & (VNET_BUFFER_F_L4_CHECKSUM_CORRECT |
                     VNET_BUFFER_F_OFFLOAD_TCP_CKSUM |
                     VNET_BUFFER_F_OFFLOAD_UDP_CKSUM);

          u32 udp_offset;
          i16 len_diff = 0;
          u8 is_tcp_udp = ip6_next_proto_is_tcp_udp (b[0], ip, &udp_offset);
          if (PREDICT_TRUE (is_tcp_udp))
            {
              udp_header_t *udp = (udp_header_t *) ((u8 *) ip + udp_offset);
              /* Don't verify UDP checksum for packets with explicit zero checksum. */
              good_l4_csum |= type == IP_BUILTIN_PROTOCOL_UDP
                && udp->checksum == 0;
              /* optimistically verify UDP length. */
              u16 ip_len, udp_len;
              ip_len = clib_net_to_host_u16 (ip->payload_length);
              udp_len = clib_net_to_host_u16 (udp->length);
              len_diff = ip_len - udp_len;
            }

          good_l4_csum |= type == IP_BUILTIN_PROTOCOL_UNKNOWN;
          len_diff = type == IP_BUILTIN_PROTOCOL_UDP ? len_diff : 0;

          u8 need_csum = type != IP_BUILTIN_PROTOCOL_UNKNOWN && !good_l4_csum
            && !(flags & VNET_BUFFER_F_L4_CHECKSUM_COMPUTED);
          if (PREDICT_FALSE (need_csum))
            {
              flags = ip6_tcp_udp_icmp_validate_checksum (vm, b[0]);
              good_l4_csum = flags & VNET_BUFFER_F_L4_CHECKSUM_CORRECT;
            }

          error = IP6_ERROR_UNKNOWN_PROTOCOL;
          error = len_diff < 0 ? IP6_ERROR_UDP_LENGTH : error;

          STATIC_ASSERT (IP6_ERROR_UDP_CHECKSUM + IP_BUILTIN_PROTOCOL_UDP ==
                         IP6_ERROR_UDP_CHECKSUM,
                         "Wrong IP6 errors constants");
          STATIC_ASSERT (IP6_ERROR_UDP_CHECKSUM + IP_BUILTIN_PROTOCOL_ICMP ==
                         IP6_ERROR_ICMP_CHECKSUM,
                         "Wrong IP6 errors constants");

          error = !good_l4_csum ? IP6_ERROR_UDP_CHECKSUM + type : error;

          /* Drop packets from unroutable hosts. */
          /* If this is a neighbor solicitation (ICMP), skip source RPF check */
          u8 unroutable = error == IP6_ERROR_UNKNOWN_PROTOCOL
            && type != IP_BUILTIN_PROTOCOL_ICMP
            && !ip6_address_is_link_local_unicast (&ip->src_address);
          if (PREDICT_FALSE (unroutable))
            {
              error =
                !ip6_urpf_loose_check (im, b[0],
                                       ip) ? IP6_ERROR_SRC_LOOKUP_MISS :
                error;
            }

          vnet_buffer (b[0])->ip.fib_index =
            vnet_buffer (b[0])->sw_if_index[VLIB_TX] != ~0 ?
            vnet_buffer (b[0])->sw_if_index[VLIB_TX] :
            vnet_buffer (b[0])->ip.fib_index;
        }                       /* head_of_feature_arc */

      next[0] = lm->local_next_by_ip_protocol[ip->protocol];
      next[0] =
        error != IP6_ERROR_UNKNOWN_PROTOCOL ? IP_LOCAL_NEXT_DROP : next[0];

      b[0]->error = error_node->errors[0];

      if (head_of_feature_arc)
        {
          if (PREDICT_TRUE (error == (u8) IP6_ERROR_UNKNOWN_PROTOCOL))
            {
              u32 next32 = next[0];
              vnet_feature_arc_start (arc_index,
                                      vnet_buffer (b[0])->sw_if_index
                                      [VLIB_RX], &next32, b[0]);
              next[0] = next32;
            }
        }

      /* next */
      b += 1;
      next += 1;
      n_left_from -= 1;
    }

  vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);
  return frame->n_vectors;
}

VLIB_NODE_FN (ip6_local_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
                               vlib_frame_t * frame)
{
  return ip6_local_inline (vm, node, frame, 1 /* head of feature arc */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ip6_local_node) =
{
  .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] = "ip6-drop",
    [IP_LOCAL_NEXT_PUNT] = "ip6-punt",
    [IP_LOCAL_NEXT_UDP_LOOKUP] = "ip6-udp-lookup",
    [IP_LOCAL_NEXT_ICMP] = "ip6-icmp-input",
    [IP_LOCAL_NEXT_REASSEMBLY] = "ip6-full-reassembly",
  },
};
/* *INDENT-ON* */

VLIB_NODE_FN (ip6_local_end_of_arc_node) (vlib_main_t * vm,
                                          vlib_node_runtime_t * node,
                                          vlib_frame_t * frame)
{
  return ip6_local_inline (vm, node, frame, 0 /* head of feature arc */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ip6_local_end_of_arc_node) = {
  .name = "ip6-local-end-of-arc",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_forward_next_trace,
  .sibling_of = "ip6-local",
};

VNET_FEATURE_INIT (ip6_local_end_of_arc, static) = {
  .arc_name = "ip6-local",
  .node_name = "ip6-local-end-of-arc",
  .runs_before = 0, /* not before any other features */
};
/* *INDENT-ON* */

#ifdef CLIB_MARCH_VARIANT
extern vlib_node_registration_t ip6_local_node;

#else

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);
}

void
ip6_unregister_protocol (u32 protocol)
{
  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] = IP_LOCAL_NEXT_PUNT;
}

clib_error_t *
ip6_probe_neighbor (vlib_main_t * vm, ip6_address_t * dst, u32 sw_if_index,
                    u8 refresh)
{
  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;
  adj_index_t ai;
  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);
  if (!h)
    return clib_error_return (0, "ICMP6 NS packet allocation failed");

  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];

  if (PREDICT_FALSE (!hi->hw_address))
    {
      return clib_error_return (0, "%U: interface %U do not support ip probe",
                                format_ip6_address, dst,
                                format_vnet_sw_if_index_name, vnm,
                                sw_if_index);
    }

  clib_memcpy_fast (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). */
  ip46_address_t nh = {
    .ip6 = *dst,
  };

  ai = adj_nbr_add_or_lock (FIB_PROTOCOL_IP6,
                            VNET_LINK_IP6, &nh, sw_if_index);
  adj = adj_get (ai);

  /* Peer has been previously resolved, retrieve glean adj instead */
  if (adj->lookup_next_index == IP_LOOKUP_NEXT_REWRITE && refresh == 0)
    {
      adj_unlock (ai);
      ai = adj_glean_add_or_lock (FIB_PROTOCOL_IP6,
                                  VNET_LINK_IP6, sw_if_index, &nh);
      adj = adj_get (ai);
    }

  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);
  }

  adj_unlock (ai);
  return /* no error */ 0;
}
#endif

typedef enum
{
  IP6_REWRITE_NEXT_DROP,
  IP6_REWRITE_NEXT_ICMP_ERROR,
  IP6_REWRITE_NEXT_FRAGMENT,
  IP6_REWRITE_N_NEXT            /* Last */
} ip6_rewrite_next_t;

/**
 * This bits of an IPv6 address to mask to construct a multicast
 * MAC address
 */
#define IP6_MCAST_ADDR_MASK 0xffffffff

always_inline void
ip6_mtu_check (vlib_buffer_t * b, u16 packet_bytes,
               u16 adj_packet_bytes, bool is_locally_generated,
               u32 * next, u32 * error)
{
  if (adj_packet_bytes >= 1280 && packet_bytes > adj_packet_bytes)
    {
      if (is_locally_generated)
        {
          /* IP fragmentation */
          ip_frag_set_vnet_buffer (b, adj_packet_bytes,
                                   IP6_FRAG_NEXT_IP6_REWRITE, 0);
          *next = IP6_REWRITE_NEXT_FRAGMENT;
          *error = IP6_ERROR_MTU_EXCEEDED;
        }
      else
        {
          *error = IP6_ERROR_MTU_EXCEEDED;
          icmp6_error_set_vnet_buffer (b, ICMP6_packet_too_big, 0,
                                       adj_packet_bytes);
          *next = IP6_REWRITE_NEXT_ICMP_ERROR;
        }
    }
}

always_inline uword
ip6_rewrite_inline_with_gso (vlib_main_t * vm,
                             vlib_node_runtime_t * node,
                             vlib_frame_t * frame,
                             int do_counters, int is_midchain, int is_mcast,
                             int do_gso)
{
  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);

  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;
  u32 thread_index = vm->thread_index;

  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;
          bool is_locally_originated0, is_locally_originated1;

          /* 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[VLIB_TX];
          adj_index1 = vnet_buffer (p1)->ip.adj_index[VLIB_TX];

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

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

          is_locally_originated0 =
            p0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED;
          if (PREDICT_TRUE (!is_locally_originated0))
            {
              i32 hop_limit0 = ip0->hop_limit;

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

              hop_limit0 -= 1;

              ip0->hop_limit = hop_limit0;

              /*
               * 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);
                }
            }
          else
            {
              p0->flags &= ~VNET_BUFFER_F_LOCALLY_ORIGINATED;
            }
          is_locally_originated1 =
            p1->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED;
          if (PREDICT_TRUE (!is_locally_originated1))
            {
              i32 hop_limit1 = ip1->hop_limit;

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

              hop_limit1 -= 1;

              ip1->hop_limit = hop_limit1;

              /*
               * If the hop count drops below 1 when forwarding, generate
               * an ICMP response.
               */
              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);
                }
            }
          else
            {
              p1->flags &= ~VNET_BUFFER_F_LOCALLY_ORIGINATED;
            }
          adj0 = adj_get (adj_index0);
          adj1 = adj_get (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;

          if (do_counters)
            {
              vlib_increment_combined_counter
                (&adjacency_counters,
                 thread_index, adj_index0, 1,
                 vlib_buffer_length_in_chain (vm, p0) + rw_len0);
              vlib_increment_combined_counter
                (&adjacency_counters,
                 thread_index, adj_index1, 1,
                 vlib_buffer_length_in_chain (vm, p1) + rw_len1);
            }

          /* Check MTU of outgoing interface. */
          u16 ip0_len =
            clib_net_to_host_u16 (ip0->payload_length) +
            sizeof (ip6_header_t);
          u16 ip1_len =
            clib_net_to_host_u16 (ip1->payload_length) +
            sizeof (ip6_header_t);
          if (do_gso && (p0->flags & VNET_BUFFER_F_GSO))
            ip0_len = gso_mtu_sz (p0);
          if (do_gso && (p1->flags & VNET_BUFFER_F_GSO))
            ip1_len = gso_mtu_sz (p1);



          ip6_mtu_check (p0, ip0_len,
                         adj0[0].rewrite_header.max_l3_packet_bytes,
                         is_locally_originated0, &next0, &error0);
          ip6_mtu_check (p1, ip1_len,
                         adj1[0].rewrite_header.max_l3_packet_bytes,
                         is_locally_originated1, &next1, &error1);

          /* Don't adjust the buffer for hop count issue; icmp-error node
           * wants to see the IP header */
          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
                  (adj0[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
                vnet_feature_arc_start (lm->output_feature_arc_index,
                                        tx_sw_if_index0, &next0, p0);
            }
          else
            {
              p0->error = error_node->errors[error0];
            }
          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
                  (adj1[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
                vnet_feature_arc_start (lm->output_feature_arc_index,
                                        tx_sw_if_index1, &next1, p1);
            }
          else
            {
              p1->error = error_node->errors[error1];
            }

          if (is_midchain)
            {
              /* before we paint on the next header, update the L4
               * checksums if required, since there's no offload on a tunnel */
              calc_checksums (vm, p0);
              calc_checksums (vm, p1);
            }

          /* 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)
            {
              if (adj0->sub_type.midchain.fixup_func)
                adj0->sub_type.midchain.fixup_func
                  (vm, adj0, p0, adj0->sub_type.midchain.fixup_data);
              if (adj1->sub_type.midchain.fixup_func)
                adj1->sub_type.midchain.fixup_func
                  (vm, adj1, p1, adj1->sub_type.midchain.fixup_data);
            }
          if (is_mcast)
            {
              /*
               * copy bytes from the IP address into the MAC rewrite
               */
              vnet_ip_mcast_fixup_header (IP6_MCAST_ADDR_MASK,
                                          adj0->
                                          rewrite_header.dst_mcast_offset,
                                          &ip0->dst_address.as_u32[3],
                                          (u8 *) ip0);
              vnet_ip_mcast_fixup_header (IP6_MCAST_ADDR_MASK,
                                          adj1->
                                          rewrite_header.dst_mcast_offset,
                                          &ip1->dst_address.as_u32[3],
                                          (u8 *) ip1);
            }

          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;
          bool is_locally_originated0;

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

          p0 = vlib_get_buffer (vm, pi0);

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

          adj0 = adj_get (adj_index0);

          ip0 = vlib_buffer_get_current (p0);

          error0 = IP6_ERROR_NONE;
          next0 = IP6_REWRITE_NEXT_DROP;

          /* Check hop limit */
          is_locally_originated0 =
            p0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED;
          if (PREDICT_TRUE (!is_locally_originated0))
            {
              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);
                }
            }
          else
            {
              p0->flags &= ~VNET_BUFFER_F_LOCALLY_ORIGINATED;
            }

          if (is_midchain)
            {
              calc_checksums (vm, p0);
            }

          /* 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;

          if (do_counters)
            {
              vlib_increment_combined_counter
                (&adjacency_counters,
                 thread_index, adj_index0, 1,
                 vlib_buffer_length_in_chain (vm, p0) + rw_len0);
            }

          /* Check MTU of outgoing interface. */
          u16 ip0_len =
            clib_net_to_host_u16 (ip0->payload_length) +
            sizeof (ip6_header_t);
          if (do_gso && (p0->flags & VNET_BUFFER_F_GSO))
            ip0_len = gso_mtu_sz (p0);

          ip6_mtu_check (p0, ip0_len,
                         adj0[0].rewrite_header.max_l3_packet_bytes,
                         is_locally_originated0, &next0, &error0);

          /* Don't adjust the buffer for hop count issue; icmp-error node
           * wants to see the IP header */
          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
                  (adj0[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
                vnet_feature_arc_start (lm->output_feature_arc_index,
                                        tx_sw_if_index0, &next0, p0);
            }
          else
            {
              p0->error = error_node->errors[error0];
            }

          if (is_midchain)
            {
              if (adj0->sub_type.midchain.fixup_func)
                adj0->sub_type.midchain.fixup_func
                  (vm, adj0, p0, adj0->sub_type.midchain.fixup_data);
            }
          if (is_mcast)
            {
              vnet_ip_mcast_fixup_header (IP6_MCAST_ADDR_MASK,
                                          adj0->
                                          rewrite_header.dst_mcast_offset,
                                          &ip0->dst_address.as_u32[3],
                                          (u8 *) ip0);
            }

          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, VLIB_TX);

  return frame->n_vectors;
}

always_inline uword
ip6_rewrite_inline (vlib_main_t * vm,
                    vlib_node_runtime_t * node,
                    vlib_frame_t * frame,
                    int do_counters, int is_midchain, int is_mcast)
{
  vnet_main_t *vnm = vnet_get_main ();
  if (PREDICT_FALSE (vnm->interface_main.gso_interface_count > 0))
    return ip6_rewrite_inline_with_gso (vm, node, frame, do_counters,
                                        is_midchain, is_mcast,
                                        1 /* do_gso */ );
  else
    return ip6_rewrite_inline_with_gso (vm, node, frame, do_counters,
                                        is_midchain, is_mcast,
                                        0 /* no do_gso */ );
}

VLIB_NODE_FN (ip6_rewrite_node) (vlib_main_t * vm,
                                 vlib_node_runtime_t * node,
                                 vlib_frame_t * frame)
{
  if (adj_are_counters_enabled ())
    return ip6_rewrite_inline (vm, node, frame, 1, 0, 0);
  else
    return ip6_rewrite_inline (vm, node, frame, 0, 0, 0);
}

VLIB_NODE_FN (ip6_rewrite_bcast_node) (vlib_main_t * vm,
                                       vlib_node_runtime_t * node,
                                       vlib_frame_t * frame)
{
  if (adj_are_counters_enabled ())
    return ip6_rewrite_inline (vm, node, frame, 1, 0, 0);
  else
    return ip6_rewrite_inline (vm, node, frame, 0, 0, 0);
}

VLIB_NODE_FN (ip6_rewrite_mcast_node) (vlib_main_t * vm,
                                       vlib_node_runtime_t * node,
                                       vlib_frame_t * frame)
{
  if (adj_are_counters_enabled ())
    return ip6_rewrite_inline (vm, node, frame, 1, 0, 1);
  else
    return ip6_rewrite_inline (vm, node, frame, 0, 0, 1);
}

VLIB_NODE_FN (ip6_midchain_node) (vlib_main_t * vm,
                                  vlib_node_runtime_t * node,
                                  vlib_frame_t * frame)
{
  if (adj_are_counters_enabled ())
    return ip6_rewrite_inline (vm, node, frame, 1, 1, 0);
  else
    return ip6_rewrite_inline (vm, node, frame, 0, 1, 0);
}

VLIB_NODE_FN (ip6_mcast_midchain_node) (vlib_main_t * vm,
                                        vlib_node_runtime_t * node,
                                        vlib_frame_t * frame)
{
  if (adj_are_counters_enabled ())
    return ip6_rewrite_inline (vm, node, frame, 1, 1, 1);
  else
    return ip6_rewrite_inline (vm, node, frame, 0, 1, 1);
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ip6_midchain_node) =
{
  .name = "ip6-midchain",
  .vector_size = sizeof (u32),
  .format_trace = format_ip6_forward_next_trace,
  .sibling_of = "ip6-rewrite",
  };

VLIB_REGISTER_NODE (ip6_rewrite_node) =
{
  .name = "ip6-rewrite",
  .vector_size = sizeof (u32),
  .format_trace = format_ip6_rewrite_trace,
  .n_next_nodes = IP6_REWRITE_N_NEXT,
  .next_nodes =
  {
    [IP6_REWRITE_NEXT_DROP] = "ip6-drop",
    [IP6_REWRITE_NEXT_ICMP_ERROR] = "ip6-icmp-error",
    [IP6_REWRITE_NEXT_FRAGMENT] = "ip6-frag",
  },
};

VLIB_REGISTER_NODE (ip6_rewrite_bcast_node) = {
  .name = "ip6-rewrite-bcast",
  .vector_size = sizeof (u32),

  .format_trace = format_ip6_rewrite_trace,
  .sibling_of = "ip6-rewrite",
};

VLIB_REGISTER_NODE (ip6_rewrite_mcast_node) =
{
  .name = "ip6-rewrite-mcast",
  .vector_size = sizeof (u32),
  .format_trace = format_ip6_rewrite_trace,
  .sibling_of = "ip6-rewrite",
};


VLIB_REGISTER_NODE (ip6_mcast_midchain_node) =
{
  .name = "ip6-mcast-midchain",
  .vector_size = sizeof (u32),
  .format_trace = format_ip6_rewrite_trace,
  .sibling_of = "ip6-rewrite",
};

/* *INDENT-ON* */

/*
 * Hop-by-Hop handling
 */
#ifndef CLIB_MARCH_VARIANT
ip6_hop_by_hop_main_t ip6_hop_by_hop_main;
#endif /* CLIB_MARCH_VARIANT */

#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")

/* *INDENT-OFF* */
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;
/* *INDENT-ON* */

/*
 * 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;

extern 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 _
};

#ifndef CLIB_MARCH_VARIANT
u8 *
format_ip6_hop_by_hop_ext_hdr (u8 * s, va_list * args)
{
  ip6_hop_by_hop_header_t *hbh0 = va_arg (*args, ip6_hop_by_hop_header_t *);
  int total_len = va_arg (*args, int);
  ip6_hop_by_hop_option_t *opt0, *limit0;
  ip6_hop_by_hop_main_t *hm = &ip6_hop_by_hop_main;
  u8 type0;

  s = format (s, "IP6_HOP_BY_HOP: next protocol %d len %d total %d",
              hbh0->protocol, (hbh0->length + 1) << 3, total_len);

  opt0 = (ip6_hop_by_hop_option_t *) (hbh0 + 1);
  limit0 = (ip6_hop_by_hop_option_t *) ((u8 *) hbh0 + total_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;
}
#endif

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
 */
VLIB_NODE_FN (ip6_hop_by_hop_node) (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;

  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 = adj_get (adj_index0);
          u32 adj_index1 = vnet_buffer (b1)->ip.adj_index[VLIB_TX];
          ip_adjacency_t *adj1 = adj_get (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_fast (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_fast (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 = adj_get (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_fast (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;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ip6_hop_by_hop_node) =
{
  .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,
};
/* *INDENT-ON* */

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;
  clib_memset (hm->options, 0, sizeof (hm->options));
  clib_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);

#ifndef CLIB_MARCH_VARIANT
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 ((u32) 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 ((u32) 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;
#endif

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

  if ((error = vlib_call_init_function (vm, vnet_feature_init)))
    return error;

  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;

  clib_bihash_init_24_8 (&(im->ip6_table[IP6_FIB_TABLE_FWDING].ip6_hash),
                         "ip6 FIB fwding table",
                         im->lookup_table_nbuckets, im->lookup_table_size);
  clib_bihash_init_24_8 (&im->ip6_table[IP6_FIB_TABLE_NON_FWDING].ip6_hash,
                         "ip6 FIB non-fwding table",
                         im->lookup_table_nbuckets, im->lookup_table_size);
  clib_bihash_init_40_8 (&im->ip6_mtable.ip6_mhash,
                         "ip6 mFIB 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,
                                     FIB_SOURCE_DEFAULT_ROUTE);
  mfib_table_find_or_create_and_lock (FIB_PROTOCOL_IP6, 0,
                                      MFIB_SOURCE_DEFAULT_ROUTE);

  {
    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;

    clib_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");
  }

  return error;
}

VLIB_INIT_FUNCTION (ip6_lookup_init);

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* */

#ifndef CLIB_MARCH_VARIANT
int
vnet_set_ip6_flow_hash (u32 table_id, u32 flow_hash_config)
{
  u32 fib_index;

  fib_index = fib_table_find (FIB_PROTOCOL_IP6, table_id);

  if (~0 == fib_index)
    return VNET_API_ERROR_NO_SUCH_FIB;

  fib_table_set_flow_hash_config (fib_index, FIB_PROTOCOL_IP6,
                                  flow_hash_config);

  return 0;
}
#endif

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 0:
      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)
        {

          u32 node_index = vlib_get_node (vm,
                                          ip6_local_node.index)->
            next_nodes[lm->local_next_by_ip_protocol[i]];
          vlib_cli_output (vm, "%d: %U", i, format_vlib_node_name, vm,
                           node_index);
        }
    }
  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* */

#ifndef CLIB_MARCH_VARIANT
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);

  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;
}
#endif

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 %U",
                         unformat_memory_size, &heapsize))
        ;
      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");

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