nat64.c

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/*
 * Copyright (c) 2017 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.
 */
/**
 * @file
 * @brief NAT64 implementation
 */

#include <nat/nat64.h>
#include <nat/nat64_db.h>
#include <nat/nat_reass.h>
#include <nat/nat_inlines.h>
#include <vnet/fib/ip4_fib.h>
#include <vppinfra/crc32.h>


nat64_main_t nat64_main;

/* *INDENT-OFF* */

/* Hook up input features */
VNET_FEATURE_INIT (nat64_in2out, static) = {
  .arc_name = "ip6-unicast",
  .node_name = "nat64-in2out",
  .runs_before = VNET_FEATURES ("ip6-lookup"),
};
VNET_FEATURE_INIT (nat64_out2in, static) = {
  .arc_name = "ip4-unicast",
  .node_name = "nat64-out2in",
  .runs_before = VNET_FEATURES ("ip4-lookup"),
};
VNET_FEATURE_INIT (nat64_in2out_handoff, static) = {
  .arc_name = "ip6-unicast",
  .node_name = "nat64-in2out-handoff",
  .runs_before = VNET_FEATURES ("ip6-lookup"),
};
VNET_FEATURE_INIT (nat64_out2in_handoff, static) = {
  .arc_name = "ip4-unicast",
  .node_name = "nat64-out2in-handoff",
  .runs_before = VNET_FEATURES ("ip4-lookup"),
};


static u8 well_known_prefix[] = {
  0x00, 0x64, 0xff, 0x9b,
  0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00
};

/* *INDENT-ON* */

static void
nat64_ip4_add_del_interface_address_cb (ip4_main_t * im, uword opaque,
                                        u32 sw_if_index,
                                        ip4_address_t * address,
                                        u32 address_length,
                                        u32 if_address_index, u32 is_delete)
{
  nat64_main_t *nm = &nat64_main;
  int i, j;

  for (i = 0; i < vec_len (nm->auto_add_sw_if_indices); i++)
    {
      if (sw_if_index == nm->auto_add_sw_if_indices[i])
        {
          if (!is_delete)
            {
              /* Don't trip over lease renewal, static config */
              for (j = 0; j < vec_len (nm->addr_pool); j++)
                if (nm->addr_pool[j].addr.as_u32 == address->as_u32)
                  return;

              (void) nat64_add_del_pool_addr (address, ~0, 1);
              return;
            }
          else
            {
              (void) nat64_add_del_pool_addr (address, ~0, 0);
              return;
            }
        }
    }
}

u32
nat64_get_worker_in2out (ip6_address_t * addr)
{
  nat64_main_t *nm = &nat64_main;
  snat_main_t *sm = nm->sm;
  u32 next_worker_index = nm->sm->first_worker_index;
  u32 hash;

#ifdef clib_crc32c_uses_intrinsics
  hash = clib_crc32c ((u8 *) addr->as_u32, 16);
#else
  u64 tmp = addr->as_u64[0] ^ addr->as_u64[1];
  hash = clib_xxhash (tmp);
#endif

  if (PREDICT_TRUE (is_pow2 (_vec_len (sm->workers))))
    next_worker_index += sm->workers[hash & (_vec_len (sm->workers) - 1)];
  else
    next_worker_index += sm->workers[hash % _vec_len (sm->workers)];

  return next_worker_index;
}

u32
nat64_get_worker_out2in (ip4_header_t * ip)
{
  nat64_main_t *nm = &nat64_main;
  snat_main_t *sm = nm->sm;
  udp_header_t *udp;
  u16 port;
  u32 proto;

  proto = ip_proto_to_snat_proto (ip->protocol);
  udp = ip4_next_header (ip);
  port = udp->dst_port;

  /* fragments */
  if (PREDICT_FALSE (ip4_is_fragment (ip)))
    {
      if (PREDICT_FALSE (nat_reass_is_drop_frag (0)))
        return vlib_get_thread_index ();

      if (PREDICT_TRUE (!ip4_is_first_fragment (ip)))
        {
          nat_reass_ip4_t *reass;

          reass = nat_ip4_reass_find (ip->src_address, ip->dst_address,
                                      ip->fragment_id, ip->protocol);

          if (reass && (reass->thread_index != (u32) ~ 0))
            return reass->thread_index;
          else
            return vlib_get_thread_index ();
        }
    }

  /* unknown protocol */
  if (PREDICT_FALSE (proto == ~0))
    {
      nat64_db_t *db;
      ip46_address_t daddr;
      nat64_db_bib_entry_t *bibe;

      clib_memset (&daddr, 0, sizeof (daddr));
      daddr.ip4.as_u32 = ip->dst_address.as_u32;

      /* *INDENT-OFF* */
      vec_foreach (db, nm->db)
        {
          bibe = nat64_db_bib_entry_find (db, &daddr, 0, ip->protocol, 0, 0);
          if (bibe)
            return (u32) (db - nm->db);
        }
      /* *INDENT-ON* */
      return vlib_get_thread_index ();
    }

  /* ICMP */
  if (PREDICT_FALSE (ip->protocol == IP_PROTOCOL_ICMP))
    {
      icmp46_header_t *icmp = (icmp46_header_t *) udp;
      icmp_echo_header_t *echo = (icmp_echo_header_t *) (icmp + 1);
      if (!icmp_is_error_message (icmp))
        port = echo->identifier;
      else
        {
          ip4_header_t *inner_ip = (ip4_header_t *) (echo + 1);
          proto = ip_proto_to_snat_proto (inner_ip->protocol);
          void *l4_header = ip4_next_header (inner_ip);
          switch (proto)
            {
            case SNAT_PROTOCOL_ICMP:
              icmp = (icmp46_header_t *) l4_header;
              echo = (icmp_echo_header_t *) (icmp + 1);
              port = echo->identifier;
              break;
            case SNAT_PROTOCOL_UDP:
            case SNAT_PROTOCOL_TCP:
              port = ((tcp_udp_header_t *) l4_header)->src_port;
              break;
            default:
              return vlib_get_thread_index ();
            }
        }
    }

  /* worker by outside port  (TCP/UDP) */
  port = clib_net_to_host_u16 (port);
  if (port > 1024)
    return nm->sm->first_worker_index + ((port - 1024) / sm->port_per_thread);

  return vlib_get_thread_index ();
}

clib_error_t *
nat64_init (vlib_main_t * vm)
{
  nat64_main_t *nm = &nat64_main;
  vlib_thread_main_t *tm = vlib_get_thread_main ();
  ip4_add_del_interface_address_callback_t cb4;
  ip4_main_t *im = &ip4_main;
  vlib_node_t *error_drop_node =
    vlib_get_node_by_name (vm, (u8 *) "error-drop");

  vec_validate (nm->db, tm->n_vlib_mains - 1);

  nm->sm = &snat_main;

  nm->fq_in2out_index = ~0;
  nm->fq_out2in_index = ~0;
  nm->error_node_index = error_drop_node->index;

  /* set session timeouts to default values */
  nm->udp_timeout = SNAT_UDP_TIMEOUT;
  nm->icmp_timeout = SNAT_ICMP_TIMEOUT;
  nm->tcp_trans_timeout = SNAT_TCP_TRANSITORY_TIMEOUT;
  nm->tcp_est_timeout = SNAT_TCP_ESTABLISHED_TIMEOUT;

  nm->total_enabled_count = 0;

  /* Set up the interface address add/del callback */
  cb4.function = nat64_ip4_add_del_interface_address_cb;
  cb4.function_opaque = 0;
  vec_add1 (im->add_del_interface_address_callbacks, cb4);
  nm->ip4_main = im;

  /* Init counters */
  nm->total_bibs.name = "total-bibs";
  nm->total_bibs.stat_segment_name = "/nat64/total-bibs";
  vlib_validate_simple_counter (&nm->total_bibs, 0);
  vlib_zero_simple_counter (&nm->total_bibs, 0);
  nm->total_sessions.name = "total-sessions";
  nm->total_sessions.stat_segment_name = "/nat64/total-sessions";
  vlib_validate_simple_counter (&nm->total_sessions, 0);
  vlib_zero_simple_counter (&nm->total_sessions, 0);

  return 0;
}

static void nat64_free_out_addr_and_port (struct nat64_db_s *db,
                                          ip4_address_t * addr, u16 port,
                                          u8 protocol);

void
nat64_set_hash (u32 bib_buckets, u32 bib_memory_size, u32 st_buckets,
                u32 st_memory_size)
{
  nat64_main_t *nm = &nat64_main;
  nat64_db_t *db;

  nm->bib_buckets = bib_buckets;
  nm->bib_memory_size = bib_memory_size;
  nm->st_buckets = st_buckets;
  nm->st_memory_size = st_memory_size;

  /* *INDENT-OFF* */
  vec_foreach (db, nm->db)
    {
      if (nat64_db_init (db, bib_buckets, bib_memory_size, st_buckets,
                         st_memory_size, nat64_free_out_addr_and_port))
        nat_log_err ("NAT64 DB init failed");
    }
  /* *INDENT-ON* */
}

int
nat64_add_del_pool_addr (ip4_address_t * addr, u32 vrf_id, u8 is_add)
{
  nat64_main_t *nm = &nat64_main;
  snat_address_t *a = 0;
  snat_interface_t *interface;
  int i;
  nat64_db_t *db;
  vlib_thread_main_t *tm = vlib_get_thread_main ();

  /* Check if address already exists */
  for (i = 0; i < vec_len (nm->addr_pool); i++)
    {
      if (nm->addr_pool[i].addr.as_u32 == addr->as_u32)
        {
          a = nm->addr_pool + i;
          break;
        }
    }

  if (is_add)
    {
      if (a)
        return VNET_API_ERROR_VALUE_EXIST;

      vec_add2 (nm->addr_pool, a, 1);
      a->addr = *addr;
      a->fib_index = ~0;
      if (vrf_id != ~0)
        a->fib_index =
          fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP6, vrf_id,
                                             FIB_SOURCE_PLUGIN_HI);
#define _(N, id, n, s) \
      clib_bitmap_alloc (a->busy_##n##_port_bitmap, 65535); \
      a->busy_##n##_ports = 0; \
      vec_validate_init_empty (a->busy_##n##_ports_per_thread, tm->n_vlib_mains - 1, 0);
      foreach_snat_protocol
#undef _
    }
  else
    {
      if (!a)
        return VNET_API_ERROR_NO_SUCH_ENTRY;

      if (a->fib_index != ~0)
        fib_table_unlock (a->fib_index, FIB_PROTOCOL_IP6,
                          FIB_SOURCE_PLUGIN_HI);
      /* Delete sessions using address */
        /* *INDENT-OFF* */
        vec_foreach (db, nm->db)
          {
            nat64_db_free_out_addr (db, &a->addr);
            vlib_set_simple_counter (&nm->total_bibs, db - nm->db, 0,
                                     db->bib.bib_entries_num);
            vlib_set_simple_counter (&nm->total_sessions, db - nm->db, 0,
                                     db->st.st_entries_num);
          }
#define _(N, id, n, s) \
      clib_bitmap_free (a->busy_##n##_port_bitmap);
      foreach_snat_protocol
#undef _
        /* *INDENT-ON* */
      vec_del1 (nm->addr_pool, i);
    }

  /* Add/del external address to FIB */
  /* *INDENT-OFF* */
  pool_foreach (interface, nm->interfaces,
  ({
    if (nat_interface_is_inside(interface))
      continue;

    snat_add_del_addr_to_fib (addr, 32, interface->sw_if_index, is_add);
    break;
  }));
  /* *INDENT-ON* */

  return 0;
}

void
nat64_pool_addr_walk (nat64_pool_addr_walk_fn_t fn, void *ctx)
{
  nat64_main_t *nm = &nat64_main;
  snat_address_t *a = 0;

  /* *INDENT-OFF* */
  vec_foreach (a, nm->addr_pool)
    {
      if (fn (a, ctx))
        break;
    };
  /* *INDENT-ON* */
}

int
nat64_add_interface_address (u32 sw_if_index, int is_add)
{
  nat64_main_t *nm = &nat64_main;
  ip4_main_t *ip4_main = nm->ip4_main;
  ip4_address_t *first_int_addr;
  int i;

  first_int_addr = ip4_interface_first_address (ip4_main, sw_if_index, 0);

  for (i = 0; i < vec_len (nm->auto_add_sw_if_indices); i++)
    {
      if (nm->auto_add_sw_if_indices[i] == sw_if_index)
        {
          if (is_add)
            return VNET_API_ERROR_VALUE_EXIST;
          else
            {
              /* if have address remove it */
              if (first_int_addr)
                (void) nat64_add_del_pool_addr (first_int_addr, ~0, 0);

              vec_del1 (nm->auto_add_sw_if_indices, i);
              return 0;
            }
        }
    }

  if (!is_add)
    return VNET_API_ERROR_NO_SUCH_ENTRY;

  /* add to the auto-address list */
  vec_add1 (nm->auto_add_sw_if_indices, sw_if_index);

  /* If the address is already bound - or static - add it now */
  if (first_int_addr)
    (void) nat64_add_del_pool_addr (first_int_addr, ~0, 1);

  return 0;
}

int
nat64_add_del_interface (u32 sw_if_index, u8 is_inside, u8 is_add)
{
  nat64_main_t *nm = &nat64_main;
  snat_interface_t *interface = 0, *i;
  snat_address_t *ap;
  const char *feature_name, *arc_name;

  /* Check if interface already exists */
  /* *INDENT-OFF* */
  pool_foreach (i, nm->interfaces,
  ({
    if (i->sw_if_index == sw_if_index)
      {
        interface = i;
        break;
      }
  }));
  /* *INDENT-ON* */

  if (is_add)
    {
      if (interface)
        goto set_flags;

      pool_get (nm->interfaces, interface);
      interface->sw_if_index = sw_if_index;
      interface->flags = 0;
    set_flags:
      if (is_inside)
        interface->flags |= NAT_INTERFACE_FLAG_IS_INSIDE;
      else
        interface->flags |= NAT_INTERFACE_FLAG_IS_OUTSIDE;

      nm->total_enabled_count++;
      vlib_process_signal_event (nm->sm->vlib_main,
                                 nm->nat64_expire_walk_node_index,
                                 NAT64_CLEANER_RESCHEDULE, 0);

    }
  else
    {
      if (!interface)
        return VNET_API_ERROR_NO_SUCH_ENTRY;

      if ((nat_interface_is_inside (interface)
           && nat_interface_is_outside (interface)))
        interface->flags &=
          is_inside ? ~NAT_INTERFACE_FLAG_IS_INSIDE :
          ~NAT_INTERFACE_FLAG_IS_OUTSIDE;
      else
        pool_put (nm->interfaces, interface);

      nm->total_enabled_count--;
    }

  if (!is_inside)
    {
      /* *INDENT-OFF* */
      vec_foreach (ap, nm->addr_pool)
        snat_add_del_addr_to_fib(&ap->addr, 32, sw_if_index, is_add);
      /* *INDENT-ON* */
    }

  if (nm->sm->num_workers > 1)
    {
      feature_name =
        is_inside ? "nat64-in2out-handoff" : "nat64-out2in-handoff";
      if (nm->fq_in2out_index == ~0)
        nm->fq_in2out_index =
          vlib_frame_queue_main_init (nat64_in2out_node.index, 0);
      if (nm->fq_out2in_index == ~0)
        nm->fq_out2in_index =
          vlib_frame_queue_main_init (nat64_out2in_node.index, 0);
    }
  else
    feature_name = is_inside ? "nat64-in2out" : "nat64-out2in";

  arc_name = is_inside ? "ip6-unicast" : "ip4-unicast";

  return vnet_feature_enable_disable (arc_name, feature_name, sw_if_index,
                                      is_add, 0, 0);
}

void
nat64_interfaces_walk (nat64_interface_walk_fn_t fn, void *ctx)
{
  nat64_main_t *nm = &nat64_main;
  snat_interface_t *i = 0;

  /* *INDENT-OFF* */
  pool_foreach (i, nm->interfaces,
  ({
    if (fn (i, ctx))
      break;
  }));
  /* *INDENT-ON* */
}

int
nat64_alloc_out_addr_and_port (u32 fib_index, snat_protocol_t proto,
                               ip4_address_t * addr, u16 * port,
                               u32 thread_index)
{
  nat64_main_t *nm = &nat64_main;
  snat_main_t *sm = nm->sm;
  snat_session_key_t k;
  u32 worker_index = 0;
  int rv;

  k.protocol = proto;

  if (sm->num_workers > 1)
    worker_index = thread_index - sm->first_worker_index;

  rv =
    sm->alloc_addr_and_port (nm->addr_pool, fib_index, thread_index, &k,
                             sm->port_per_thread, worker_index);

  if (!rv)
    {
      *port = k.port;
      addr->as_u32 = k.addr.as_u32;
    }

  return rv;
}

static void
nat64_free_out_addr_and_port (struct nat64_db_s *db, ip4_address_t * addr,
                              u16 port, u8 protocol)
{
  nat64_main_t *nm = &nat64_main;
  int i;
  snat_address_t *a;
  u32 thread_index = db - nm->db;
  snat_protocol_t proto = ip_proto_to_snat_proto (protocol);
  u16 port_host_byte_order = clib_net_to_host_u16 (port);

  for (i = 0; i < vec_len (nm->addr_pool); i++)
    {
      a = nm->addr_pool + i;
      if (addr->as_u32 != a->addr.as_u32)
        continue;
      switch (proto)
        {
#define _(N, j, n, s) \
        case SNAT_PROTOCOL_##N: \
          ASSERT (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, \
                  port_host_byte_order) == 1); \
          clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, port, 0); \
          a->busy_##n##_ports--; \
          a->busy_##n##_ports_per_thread[thread_index]--; \
          break;
          foreach_snat_protocol
#undef _
        default:
          nat_log_notice ("unknown protocol");
          return;
        }
      break;
    }
}

/**
 * @brief Add/delete static BIB entry in worker thread.
 */
static uword
nat64_static_bib_worker_fn (vlib_main_t * vm, vlib_node_runtime_t * rt,
                            vlib_frame_t * f)
{
  nat64_main_t *nm = &nat64_main;
  u32 thread_index = vm->thread_index;
  nat64_db_t *db = &nm->db[thread_index];
  nat64_static_bib_to_update_t *static_bib;
  nat64_db_bib_entry_t *bibe;
  ip46_address_t addr;

  /* *INDENT-OFF* */
  pool_foreach (static_bib, nm->static_bibs,
  ({
    if ((static_bib->thread_index != thread_index) || (static_bib->done))
      continue;

    if (static_bib->is_add)
      {
          (void) nat64_db_bib_entry_create (db, &static_bib->in_addr,
                                            &static_bib->out_addr,
                                            static_bib->in_port,
                                            static_bib->out_port,
                                            static_bib->fib_index,
                                            static_bib->proto, 1);
          vlib_set_simple_counter (&nm->total_bibs, thread_index, 0,
                                   db->bib.bib_entries_num);
      }
    else
      {
        addr.as_u64[0] = static_bib->in_addr.as_u64[0];
        addr.as_u64[1] = static_bib->in_addr.as_u64[1];
        bibe = nat64_db_bib_entry_find (db, &addr, static_bib->in_port,
                                        static_bib->proto,
                                        static_bib->fib_index, 1);
        if (bibe)
          {
            nat64_db_bib_entry_free (db, bibe);
            vlib_set_simple_counter (&nm->total_bibs, thread_index, 0,
                                     db->bib.bib_entries_num);
            vlib_set_simple_counter (&nm->total_sessions, thread_index, 0,
                                     db->st.st_entries_num);
          }
      }

      static_bib->done = 1;
  }));
  /* *INDENT-ON* */

  return 0;
}

static vlib_node_registration_t nat64_static_bib_worker_node;

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (nat64_static_bib_worker_node, static) = {
    .function = nat64_static_bib_worker_fn,
    .type = VLIB_NODE_TYPE_INPUT,
    .state = VLIB_NODE_STATE_INTERRUPT,
    .name = "nat64-static-bib-worker",
};
/* *INDENT-ON* */

int
nat64_add_del_static_bib_entry (ip6_address_t * in_addr,
                                ip4_address_t * out_addr, u16 in_port,
                                u16 out_port, u8 proto, u32 vrf_id, u8 is_add)
{
  nat64_main_t *nm = &nat64_main;
  nat64_db_bib_entry_t *bibe;
  u32 fib_index = fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP6, vrf_id,
                                                     FIB_SOURCE_PLUGIN_HI);
  snat_protocol_t p = ip_proto_to_snat_proto (proto);
  ip46_address_t addr;
  int i;
  snat_address_t *a;
  u32 thread_index = 0;
  nat64_db_t *db;
  nat64_static_bib_to_update_t *static_bib;
  vlib_main_t *worker_vm;
  u32 *to_be_free = 0, *index;

  if (nm->sm->num_workers > 1)
    {
      thread_index = nat64_get_worker_in2out (in_addr);
      db = &nm->db[thread_index];
    }
  else
    db = &nm->db[nm->sm->num_workers];

  addr.as_u64[0] = in_addr->as_u64[0];
  addr.as_u64[1] = in_addr->as_u64[1];
  bibe =
    nat64_db_bib_entry_find (db, &addr, clib_host_to_net_u16 (in_port),
                             proto, fib_index, 1);

  if (is_add)
    {
      if (bibe)
        return VNET_API_ERROR_VALUE_EXIST;

      /* outside port must be assigned to same thread as internall address */
      if ((out_port > 1024) && (nm->sm->num_workers > 1))
        {
          if (thread_index != ((out_port - 1024) / nm->sm->port_per_thread))
            return VNET_API_ERROR_INVALID_VALUE_2;
        }

      for (i = 0; i < vec_len (nm->addr_pool); i++)
        {
          a = nm->addr_pool + i;
          if (out_addr->as_u32 != a->addr.as_u32)
            continue;
          switch (p)
            {
#define _(N, j, n, s) \
            case SNAT_PROTOCOL_##N: \
              if (clib_bitmap_get_no_check (a->busy_##n##_port_bitmap, \
                                            out_port)) \
                return VNET_API_ERROR_INVALID_VALUE; \
              clib_bitmap_set_no_check (a->busy_##n##_port_bitmap, \
                                        out_port, 1); \
              if (out_port > 1024) \
                { \
                  a->busy_##n##_ports++; \
                  a->busy_##n##_ports_per_thread[thread_index]++; \
                } \
              break;
              foreach_snat_protocol
#undef _
            default:
              clib_memset (&addr, 0, sizeof (addr));
              addr.ip4.as_u32 = out_addr->as_u32;
              if (nat64_db_bib_entry_find (db, &addr, 0, proto, fib_index, 0))
                return VNET_API_ERROR_INVALID_VALUE;
            }
          break;
        }
      if (!nm->sm->num_workers)
        {
          bibe =
            nat64_db_bib_entry_create (db, in_addr, out_addr,
                                       clib_host_to_net_u16 (in_port),
                                       clib_host_to_net_u16 (out_port),
                                       fib_index, proto, 1);
          if (!bibe)
            return VNET_API_ERROR_UNSPECIFIED;

          vlib_set_simple_counter (&nm->total_bibs, thread_index, 0,
                                   db->bib.bib_entries_num);
        }
    }
  else
    {
      if (!bibe)
        return VNET_API_ERROR_NO_SUCH_ENTRY;

      if (!nm->sm->num_workers)
        {
          nat64_db_bib_entry_free (db, bibe);
          vlib_set_simple_counter (&nm->total_bibs, thread_index, 0,
                                   db->bib.bib_entries_num);
        }
    }

  if (nm->sm->num_workers)
    {
      /* *INDENT-OFF* */
      pool_foreach (static_bib, nm->static_bibs,
      ({
        if (static_bib->done)
          vec_add1 (to_be_free, static_bib - nm->static_bibs);
      }));
      vec_foreach (index, to_be_free)
        pool_put_index (nm->static_bibs, index[0]);
      /* *INDENT-ON* */
      vec_free (to_be_free);
      pool_get (nm->static_bibs, static_bib);
      static_bib->in_addr.as_u64[0] = in_addr->as_u64[0];
      static_bib->in_addr.as_u64[1] = in_addr->as_u64[1];
      static_bib->in_port = clib_host_to_net_u16 (in_port);
      static_bib->out_addr.as_u32 = out_addr->as_u32;
      static_bib->out_port = clib_host_to_net_u16 (out_port);
      static_bib->fib_index = fib_index;
      static_bib->proto = proto;
      static_bib->is_add = is_add;
      static_bib->thread_index = thread_index;
      static_bib->done = 0;
      worker_vm = vlib_mains[thread_index];
      if (worker_vm)
        vlib_node_set_interrupt_pending (worker_vm,
                                         nat64_static_bib_worker_node.index);
      else
        return VNET_API_ERROR_UNSPECIFIED;
    }

  return 0;
}

int
nat64_set_udp_timeout (u32 timeout)
{
  nat64_main_t *nm = &nat64_main;

  if (timeout == 0)
    nm->udp_timeout = SNAT_UDP_TIMEOUT;
  else
    nm->udp_timeout = timeout;

  return 0;
}

u32
nat64_get_udp_timeout (void)
{
  nat64_main_t *nm = &nat64_main;

  return nm->udp_timeout;
}

int
nat64_set_icmp_timeout (u32 timeout)
{
  nat64_main_t *nm = &nat64_main;

  if (timeout == 0)
    nm->icmp_timeout = SNAT_ICMP_TIMEOUT;
  else
    nm->icmp_timeout = timeout;

  return 0;
}

u32
nat64_get_icmp_timeout (void)
{
  nat64_main_t *nm = &nat64_main;

  return nm->icmp_timeout;
}

int
nat64_set_tcp_timeouts (u32 trans, u32 est)
{
  nat64_main_t *nm = &nat64_main;

  if (trans == 0)
    nm->tcp_trans_timeout = SNAT_TCP_TRANSITORY_TIMEOUT;
  else
    nm->tcp_trans_timeout = trans;

  if (est == 0)
    nm->tcp_est_timeout = SNAT_TCP_ESTABLISHED_TIMEOUT;
  else
    nm->tcp_est_timeout = est;

  return 0;
}

u32
nat64_get_tcp_trans_timeout (void)
{
  nat64_main_t *nm = &nat64_main;

  return nm->tcp_trans_timeout;
}

u32
nat64_get_tcp_est_timeout (void)
{
  nat64_main_t *nm = &nat64_main;

  return nm->tcp_est_timeout;
}

void
nat64_session_reset_timeout (nat64_db_st_entry_t * ste, vlib_main_t * vm)
{
  nat64_main_t *nm = &nat64_main;
  u32 now = (u32) vlib_time_now (vm);

  switch (ip_proto_to_snat_proto (ste->proto))
    {
    case SNAT_PROTOCOL_ICMP:
      ste->expire = now + nm->icmp_timeout;
      return;
    case SNAT_PROTOCOL_TCP:
      {
        switch (ste->tcp_state)
          {
          case NAT64_TCP_STATE_V4_INIT:
          case NAT64_TCP_STATE_V6_INIT:
          case NAT64_TCP_STATE_V4_FIN_RCV:
          case NAT64_TCP_STATE_V6_FIN_RCV:
          case NAT64_TCP_STATE_V6_FIN_V4_FIN_RCV:
          case NAT64_TCP_STATE_TRANS:
            ste->expire = now + nm->tcp_trans_timeout;
            return;
          case NAT64_TCP_STATE_ESTABLISHED:
            ste->expire = now + nm->tcp_est_timeout;
            return;
          default:
            return;
          }
      }
    case SNAT_PROTOCOL_UDP:
      ste->expire = now + nm->udp_timeout;
      return;
    default:
      ste->expire = now + nm->udp_timeout;
      return;
    }
}

void
nat64_tcp_session_set_state (nat64_db_st_entry_t * ste, tcp_header_t * tcp,
                             u8 is_ip6)
{
  switch (ste->tcp_state)
    {
    case NAT64_TCP_STATE_CLOSED:
      {
        if (tcp->flags & TCP_FLAG_SYN)
          {
            if (is_ip6)
              ste->tcp_state = NAT64_TCP_STATE_V6_INIT;
            else
              ste->tcp_state = NAT64_TCP_STATE_V4_INIT;
          }
        return;
      }
    case NAT64_TCP_STATE_V4_INIT:
      {
        if (is_ip6 && (tcp->flags & TCP_FLAG_SYN))
          ste->tcp_state = NAT64_TCP_STATE_ESTABLISHED;
        return;
      }
    case NAT64_TCP_STATE_V6_INIT:
      {
        if (!is_ip6 && (tcp->flags & TCP_FLAG_SYN))
          ste->tcp_state = NAT64_TCP_STATE_ESTABLISHED;
        return;
      }
    case NAT64_TCP_STATE_ESTABLISHED:
      {
        if (tcp->flags & TCP_FLAG_FIN)
          {
            if (is_ip6)
              ste->tcp_state = NAT64_TCP_STATE_V6_FIN_RCV;
            else
              ste->tcp_state = NAT64_TCP_STATE_V4_FIN_RCV;
          }
        else if (tcp->flags & TCP_FLAG_RST)
          {
            ste->tcp_state = NAT64_TCP_STATE_TRANS;
          }
        return;
      }
    case NAT64_TCP_STATE_V4_FIN_RCV:
      {
        if (is_ip6 && (tcp->flags & TCP_FLAG_FIN))
          ste->tcp_state = NAT64_TCP_STATE_V6_FIN_V4_FIN_RCV;
        return;
      }
    case NAT64_TCP_STATE_V6_FIN_RCV:
      {
        if (!is_ip6 && (tcp->flags & TCP_FLAG_FIN))
          ste->tcp_state = NAT64_TCP_STATE_V6_FIN_V4_FIN_RCV;
        return;
      }
    case NAT64_TCP_STATE_TRANS:
      {
        if (!(tcp->flags & TCP_FLAG_RST))
          ste->tcp_state = NAT64_TCP_STATE_ESTABLISHED;
        return;
      }
    default:
      return;
    }
}

int
nat64_add_del_prefix (ip6_address_t * prefix, u8 plen, u32 vrf_id, u8 is_add)
{
  nat64_main_t *nm = &nat64_main;
  nat64_prefix_t *p = 0;
  int i;

  /* Verify prefix length */
  if (plen != 32 && plen != 40 && plen != 48 && plen != 56 && plen != 64
      && plen != 96)
    return VNET_API_ERROR_INVALID_VALUE;

  /* Check if tenant already have prefix */
  for (i = 0; i < vec_len (nm->pref64); i++)
    {
      if (nm->pref64[i].vrf_id == vrf_id)
        {
          p = nm->pref64 + i;
          break;
        }
    }

  if (is_add)
    {
      if (!p)
        {
          vec_add2 (nm->pref64, p, 1);
          p->fib_index =
            fib_table_find_or_create_and_lock (FIB_PROTOCOL_IP6, vrf_id,
                                               FIB_SOURCE_PLUGIN_HI);
          p->vrf_id = vrf_id;
        }

      p->prefix.as_u64[0] = prefix->as_u64[0];
      p->prefix.as_u64[1] = prefix->as_u64[1];
      p->plen = plen;
    }
  else
    {
      if (!p)
        return VNET_API_ERROR_NO_SUCH_ENTRY;

      vec_del1 (nm->pref64, i);
    }

  return 0;
}

void
nat64_prefix_walk (nat64_prefix_walk_fn_t fn, void *ctx)
{
  nat64_main_t *nm = &nat64_main;
  nat64_prefix_t *p = 0;

  /* *INDENT-OFF* */
  vec_foreach (p, nm->pref64)
    {
      if (fn (p, ctx))
        break;
    };
  /* *INDENT-ON* */
}

void
nat64_compose_ip6 (ip6_address_t * ip6, ip4_address_t * ip4, u32 fib_index)
{
  nat64_main_t *nm = &nat64_main;
  nat64_prefix_t *p, *gp = 0, *prefix = 0;

  /* *INDENT-OFF* */
  vec_foreach (p, nm->pref64)
    {
      if (p->fib_index == fib_index)
        {
          prefix = p;
          break;
        }

      if (p->fib_index == 0)
        gp = p;
    };
  /* *INDENT-ON* */

  if (!prefix)
    prefix = gp;

  if (prefix)
    {
      clib_memcpy_fast (ip6, &p->prefix, sizeof (ip6_address_t));
      switch (p->plen)
        {
        case 32:
          ip6->as_u32[1] = ip4->as_u32;
          break;
        case 40:
          ip6->as_u8[5] = ip4->as_u8[0];
          ip6->as_u8[6] = ip4->as_u8[1];
          ip6->as_u8[7] = ip4->as_u8[2];
          ip6->as_u8[9] = ip4->as_u8[3];
          break;
        case 48:
          ip6->as_u8[6] = ip4->as_u8[0];
          ip6->as_u8[7] = ip4->as_u8[1];
          ip6->as_u8[9] = ip4->as_u8[2];
          ip6->as_u8[10] = ip4->as_u8[3];
          break;
        case 56:
          ip6->as_u8[7] = ip4->as_u8[0];
          ip6->as_u8[9] = ip4->as_u8[1];
          ip6->as_u8[10] = ip4->as_u8[2];
          ip6->as_u8[11] = ip4->as_u8[3];
          break;
        case 64:
          ip6->as_u8[9] = ip4->as_u8[0];
          ip6->as_u8[10] = ip4->as_u8[1];
          ip6->as_u8[11] = ip4->as_u8[2];
          ip6->as_u8[12] = ip4->as_u8[3];
          break;
        case 96:
          ip6->as_u32[3] = ip4->as_u32;
          break;
        default:
          nat_log_notice ("invalid prefix length");
          break;
        }
    }
  else
    {
      clib_memcpy_fast (ip6, well_known_prefix, sizeof (ip6_address_t));
      ip6->as_u32[3] = ip4->as_u32;
    }
}

void
nat64_extract_ip4 (ip6_address_t * ip6, ip4_address_t * ip4, u32 fib_index)
{
  nat64_main_t *nm = &nat64_main;
  nat64_prefix_t *p, *gp = 0;
  u8 plen = 0;

  /* *INDENT-OFF* */
  vec_foreach (p, nm->pref64)
    {
      if (p->fib_index == fib_index)
        {
          plen = p->plen;
          break;
        }

      if (p->vrf_id == 0)
        gp = p;
    };
  /* *INDENT-ON* */

  if (!plen)
    {
      if (gp)
        plen = gp->plen;
      else
        plen = 96;
    }

  switch (plen)
    {
    case 32:
      ip4->as_u32 = ip6->as_u32[1];
      break;
    case 40:
      ip4->as_u8[0] = ip6->as_u8[5];
      ip4->as_u8[1] = ip6->as_u8[6];
      ip4->as_u8[2] = ip6->as_u8[7];
      ip4->as_u8[3] = ip6->as_u8[9];
      break;
    case 48:
      ip4->as_u8[0] = ip6->as_u8[6];
      ip4->as_u8[1] = ip6->as_u8[7];
      ip4->as_u8[2] = ip6->as_u8[9];
      ip4->as_u8[3] = ip6->as_u8[10];
      break;
    case 56:
      ip4->as_u8[0] = ip6->as_u8[7];
      ip4->as_u8[1] = ip6->as_u8[9];
      ip4->as_u8[2] = ip6->as_u8[10];
      ip4->as_u8[3] = ip6->as_u8[11];
      break;
    case 64:
      ip4->as_u8[0] = ip6->as_u8[9];
      ip4->as_u8[1] = ip6->as_u8[10];
      ip4->as_u8[2] = ip6->as_u8[11];
      ip4->as_u8[3] = ip6->as_u8[12];
      break;
    case 96:
      ip4->as_u32 = ip6->as_u32[3];
      break;
    default:
      nat_log_notice ("invalid prefix length");
      break;
    }
}

/**
 * @brief Per worker process checking expire time for NAT64 sessions.
 */
static uword
nat64_expire_worker_walk_fn (vlib_main_t * vm, vlib_node_runtime_t * rt,
                             vlib_frame_t * f)
{
  nat64_main_t *nm = &nat64_main;
  u32 thread_index = vm->thread_index;
  nat64_db_t *db = &nm->db[thread_index];
  u32 now = (u32) vlib_time_now (vm);

  nad64_db_st_free_expired (db, now);
  vlib_set_simple_counter (&nm->total_bibs, thread_index, 0,
                           db->bib.bib_entries_num);
  vlib_set_simple_counter (&nm->total_sessions, thread_index, 0,
                           db->st.st_entries_num);

  return 0;
}

static vlib_node_registration_t nat64_expire_worker_walk_node;

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (nat64_expire_worker_walk_node, static) = {
    .function = nat64_expire_worker_walk_fn,
    .type = VLIB_NODE_TYPE_INPUT,
    .state = VLIB_NODE_STATE_INTERRUPT,
    .name = "nat64-expire-worker-walk",
};
/* *INDENT-ON* */

static vlib_node_registration_t nat64_expire_walk_node;

/**
 * @brief Centralized process to drive per worker expire walk.
 */
static uword
nat64_expire_walk_fn (vlib_main_t * vm, vlib_node_runtime_t * rt,
                      vlib_frame_t * f)
{
  nat64_main_t *nm = &nat64_main;
  vlib_main_t **worker_vms = 0, *worker_vm;
  int i;
  uword event_type, *event_data = 0;

  nm->nat64_expire_walk_node_index = nat64_expire_walk_node.index;

  if (vec_len (vlib_mains) == 0)
    vec_add1 (worker_vms, vm);
  else
    {
      for (i = 0; i < vec_len (vlib_mains); i++)
        {
          worker_vm = vlib_mains[i];
          if (worker_vm)
            vec_add1 (worker_vms, worker_vm);
        }
    }

  while (1)
    {
      if (nm->total_enabled_count)
        {
          vlib_process_wait_for_event_or_clock (vm, 10.0);
          event_type = vlib_process_get_events (vm, &event_data);
        }
      else
        {
          vlib_process_wait_for_event (vm);
          event_type = vlib_process_get_events (vm, &event_data);
        }

      switch (event_type)
        {
        case ~0:
          break;
        case NAT64_CLEANER_RESCHEDULE:
          break;
        default:
          nat_log_notice ("unknown event %u", event_type);
          break;
        }

      for (i = 0; i < vec_len (worker_vms); i++)
        {
          worker_vm = worker_vms[i];
          vlib_node_set_interrupt_pending (worker_vm,
                                           nat64_expire_worker_walk_node.index);
        }
    }

  return 0;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (nat64_expire_walk_node, static) = {
    .function = nat64_expire_walk_fn,
    .type = VLIB_NODE_TYPE_PROCESS,
    .name = "nat64-expire-walk",
};
/* *INDENT-ON* */

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