text: /*
   * l2_fib.c : layer 2 forwarding table (aka mac table)
   *
   * Copyright (c) 2013 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.
   */
  
  
  #include <vlib/vlib.h>
  #include <vnet/vnet.h>
  #include <vnet/pg/pg.h>
  #include <vnet/ethernet/ethernet.h>
  #include <vlib/cli.h>
  
  #include <vppinfra/error.h>
  #include <vppinfra/hash.h>
  #include <vnet/l2/l2_input.h>
  #include <vnet/l2/l2_fib.h>
  #include <vnet/l2/l2_learn.h>
  #include <vnet/l2/l2_bd.h>
  
  #include <vppinfra/bihash_template.c>
  
  #include <vlibmemory/api.h>
  #include <vnet/vnet_msg_enum.h>
  
  #define vl_typedefs		/* define message structures */
  #include <vnet/vnet_all_api_h.h>
  #undef vl_typedefs
  
  #define vl_endianfun		/* define message structures */
  #include <vnet/vnet_all_api_h.h>
  #undef vl_endianfun
  
  /**
   * @file
   * @brief Ethernet MAC Address FIB Table Management.
   *
   * The MAC Address forwarding table for bridge-domains is called the l2fib.
   * Entries are added automatically as part of mac learning, but MAC Addresses
   * entries can also be added manually.
   *
   */
  
  l2fib_main_t l2fib_main;
  
  u8 *
  format_l2fib_entry_result_flags (u8 * s, va_list * args)
  {
    l2fib_entry_result_flags_t flags = va_arg (*args, int);
  
    if (L2FIB_ENTRY_RESULT_FLAG_NONE == flags)
      {
        s = format (s, "none");
      }
    else
      {
  #define _(a,v,t) {                              \
        if (flags & L2FIB_ENTRY_RESULT_FLAG_##a)  \
          s = format (s, "%s ", t);               \
      }
        foreach_l2fib_entry_result_attr
  #undef _
      }
    return (s);
  }
  
  static void
  incr_mac_address (u8 * mac)
  {
    u64 tmp = *((u64 *) mac);
    tmp = clib_net_to_host_u64 (tmp);
    tmp += 1 << 16;		/* skip unused (least significant) octets */
    tmp = clib_host_to_net_u64 (tmp);
  
    clib_memcpy_fast (mac, &tmp, 6);
  }
  
  /** Format sw_if_index. If the value is ~0, use the text "N/A" */
  u8 *
  format_vnet_sw_if_index_name_with_NA (u8 * s, va_list * args)
  {
    vnet_main_t *vnm = va_arg (*args, vnet_main_t *);
    u32 sw_if_index = va_arg (*args, u32);
    if (sw_if_index == ~0)
      return format (s, "N/A");
  
    vnet_sw_interface_t *swif = vnet_get_sw_interface_safe (vnm, sw_if_index);
    if (!swif)
      return format (s, "Stale");
  
    return format (s, "%U", format_vnet_sw_interface_name, vnm,
  		 vnet_get_sw_interface_safe (vnm, sw_if_index));
  }
  
  typedef struct l2fib_dump_walk_ctx_t_
  {
    u32 bd_index;
    l2fib_entry_key_t *l2fe_key;
    l2fib_entry_result_t *l2fe_res;
  } l2fib_dump_walk_ctx_t;
  
  static void
  l2fib_dump_walk_cb (BVT (clib_bihash_kv) * kvp, void *arg)
  {
    l2fib_dump_walk_ctx_t *ctx = arg;
    l2fib_entry_result_t result;
    l2fib_entry_key_t key;
  
    key.raw = kvp->key;
    result.raw = kvp->value;
  
    if ((ctx->bd_index == ~0) || (ctx->bd_index == key.fields.bd_index))
      {
        vec_add1 (ctx->l2fe_key, key);
        vec_add1 (ctx->l2fe_res, result);
      }
  }
  
  void
  l2fib_table_dump (u32 bd_index,
  		  l2fib_entry_key_t ** l2fe_key,
  		  l2fib_entry_result_t ** l2fe_res)
  {
    l2fib_main_t *msm = &l2fib_main;
    l2fib_dump_walk_ctx_t ctx = {
      .bd_index = bd_index,
    };
  
    BV (clib_bihash_foreach_key_value_pair)
      (&msm->mac_table, l2fib_dump_walk_cb, &ctx);
  
    *l2fe_key = ctx.l2fe_key;
    *l2fe_res = ctx.l2fe_res;
  }
  
  typedef struct l2fib_show_walk_ctx_t_
  {
    u8 first_entry;
    u8 verbose;
    vlib_main_t *vm;
    vnet_main_t *vnm;
    u32 total_entries;
    u32 bd_index;
    u8 learn;
    u8 add;
    u8 now;
  } l2fib_show_walk_ctx_t;
  
  static void
  l2fib_show_walk_cb (BVT (clib_bihash_kv) * kvp, void *arg)
  {
    l2fib_show_walk_ctx_t *ctx = arg;
    l2_bridge_domain_t *bd_config;
    l2fib_entry_result_t result;
    l2fib_entry_key_t key;
  
    if (ctx->verbose && ctx->first_entry)
      {
        ctx->first_entry = 0;
        vlib_cli_output (ctx->vm,
  		       "%=19s%=7s%=7s%=8s%=9s%=7s%=7s%=5s%=30s",
  		       "Mac-Address", "BD-Idx", "If-Idx",
  		       "BSN-ISN", "Age(min)", "static", "filter",
  		       "bvi", "Interface-Name");
      }
  
    key.raw = kvp->key;
    result.raw = kvp->value;
    ctx->total_entries++;
  
    if (ctx->verbose &&
        ((ctx->bd_index >> 31) || (ctx->bd_index == key.fields.bd_index)))
      {
        u8 *s = NULL;
  
        if (ctx->learn && l2fib_entry_result_is_set_AGE_NOT (&result))
  	return;			/* skip provisioned macs */
  
        if (ctx->add && !l2fib_entry_result_is_set_AGE_NOT (&result))
  	return;			/* skip learned macs */
  
        bd_config = vec_elt_at_index (l2input_main.bd_configs,
  				    key.fields.bd_index);
  
        if (l2fib_entry_result_is_set_AGE_NOT (&result))
  	s = format (s, "no");
        else if (bd_config->mac_age == 0)
  	s = format (s, "-");
        else
  	{
  	  i16 delta = ctx->now - result.fields.timestamp;
  	  delta += delta < 0 ? 256 : 0;
  	  s = format (s, "%d", delta);
  	}
  
        vlib_cli_output (ctx->vm,
  		       "%=19U%=7d%=7d %3d/%-3d%=9v%=7s%=7s%=5s%=30U",
  		       format_ethernet_address, key.fields.mac,
  		       key.fields.bd_index,
  		       result.fields.sw_if_index == ~0
  		       ? -1 : result.fields.sw_if_index,
  		       result.fields.sn.bd, result.fields.sn.swif, s,
  		       l2fib_entry_result_is_set_STATIC (&result) ? "*" : "-",
  		       l2fib_entry_result_is_set_FILTER (&result) ? "*" : "-",
  		       l2fib_entry_result_is_set_BVI (&result) ? "*" : "-",
  		       format_vnet_sw_if_index_name_with_NA,
  		       ctx->vnm, result.fields.sw_if_index);
        vec_free (s);
      }
  }
  
  /** Display the contents of the l2fib. */
  static clib_error_t *
  show_l2fib (vlib_main_t * vm,
  	    unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    bd_main_t *bdm = &bd_main;
    l2fib_main_t *msm = &l2fib_main;
    u8 raw = 0;
    u32 bd_id;
    l2fib_show_walk_ctx_t ctx = {
      .first_entry = 1,
      .bd_index = ~0,
      .now = (u8) (vlib_time_now (vm) / 60),
      .vm = vm,
      .vnm = msm->vnet_main,
    };
  
    while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
      {
        if (unformat (input, "raw"))
  	{
  	  raw = 1;
  	  ctx.verbose = 0;
  	  break;
  	}
        else if (unformat (input, "verbose"))
  	ctx.verbose = 1;
        else if (unformat (input, "all"))
  	ctx.verbose = 1;
        else if (unformat (input, "bd_index %d", &ctx.bd_index))
  	ctx.verbose = 1;
        else if (unformat (input, "learn"))
  	{
  	  ctx.add = 0;
  	  ctx.learn = 1;
  	  ctx.verbose = 1;
  	}
        else if (unformat (input, "add"))
  	{
  	  ctx.learn = 0;
  	  ctx.add = 1;
  	  ctx.verbose = 1;
  	}
        else if (unformat (input, "bd_id %d", &bd_id))
  	{
  	  uword *p = hash_get (bdm->bd_index_by_bd_id, bd_id);
  	  if (p)
  	    {
  	      ctx.verbose = 1;
  	      ctx.bd_index = p[0];
  	    }
  	  else
  	    return clib_error_return (0,
  				      "bridge domain id %d doesn't exist\n",
  				      bd_id);
  	}
        else
  	break;
      }
  
    BV (clib_bihash_foreach_key_value_pair)
      (&msm->mac_table, l2fib_show_walk_cb, &ctx);
  
    if (ctx.total_entries == 0)
      vlib_cli_output (vm, "no l2fib entries");
    else
      {
        l2learn_main_t *lm = &l2learn_main;
        vlib_cli_output (vm, "L2FIB total/learned entries: %d/%d  "
  		       "Last scan time: %.4esec  Learn limit: %d ",
  		       ctx.total_entries, lm->global_learn_count,
  		       msm->age_scan_duration, lm->global_learn_limit);
        if (lm->client_pid)
  	vlib_cli_output (vm, "L2MAC events client PID: %d  "
  			 "Last e-scan time: %.4esec  Delay: %.2esec  "
  			 "Max macs in event: %d",
  			 lm->client_pid, msm->evt_scan_duration,
  			 msm->event_scan_delay, msm->max_macs_in_event);
      }
  
    if (raw)
      vlib_cli_output (vm, "Raw Hash Table:\n%U\n",
  		     BV (format_bihash), &msm->mac_table, 1 /* verbose */ );
  
    return 0;
  }
  
  /*?
   * This command displays the MAC Address entries of the L2 FIB table.
   * Output can be filtered to just get the number of MAC Addresses or display
   * each MAC Address for all bridge domains or just a single bridge domain.
   *
   * @cliexpar
   * Example of how to display the number of MAC Address entries in the L2
   * FIB table:
   * @cliexstart{show l2fib}
   * 3 l2fib entries
   * @cliexend
   * Example of how to display all the MAC Address entries in the L2
   * FIB table:
   * @cliexstart{show l2fib all}
   *     Mac Address     BD Idx           Interface           Index  static  filter  bvi  refresh  timestamp
   *  52:54:00:53:18:33    1      GigabitEthernet0/8/0.200      3       0       0     0      0         0
   *  52:54:00:53:18:55    1      GigabitEthernet0/8/0.200      3       1       0     0      0         0
   *  52:54:00:53:18:77    1                 N/A                -1      1       1     0      0         0
   * 3 l2fib entries
   * @cliexend
  ?*/
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (show_l2fib_cli, static) = {
    .path = "show l2fib",
    .short_help = "show l2fib [all] | [bd_id <nn> | bd_index <nn>] [learn | add] | [raw]",
    .function = show_l2fib,
  };
  /* *INDENT-ON* */
  
  
  /* Remove all entries from the l2fib */
  void
  l2fib_clear_table (void)
  {
    l2fib_main_t *mp = &l2fib_main;
  
    /* Remove all entries */
    BV (clib_bihash_free) (&mp->mac_table);
    BV (clib_bihash_init) (&mp->mac_table, "l2fib mac table",
  			 L2FIB_NUM_BUCKETS, L2FIB_MEMORY_SIZE);
    l2learn_main.global_learn_count = 0;
  }
  
  /** Clear all entries in L2FIB.
   * @TODO: Later we may want a way to remove only the non-static entries
   */
  static clib_error_t *
  clear_l2fib (vlib_main_t * vm,
  	     unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    l2fib_clear_table ();
    return 0;
  }
  
  /*?
   * This command clears all the MAC Address entries from the L2 FIB table.
   *
   * @cliexpar
   * Example of how to clear the L2 FIB Table:
   * @cliexcmd{clear l2fib}
   * Example to show the L2 FIB Table has been cleared:
   * @cliexstart{show l2fib verbose}
   * no l2fib entries
   * @cliexend
  ?*/
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (clear_l2fib_cli, static) = {
    .path = "clear l2fib",
    .short_help = "clear l2fib",
    .function = clear_l2fib,
  };
  /* *INDENT-ON* */
  
  static inline l2fib_seq_num_t
  l2fib_cur_seq_num (u32 bd_index, u32 sw_if_index)
  {
    l2_bridge_domain_t *bd_config = l2input_bd_config (bd_index);
    /* *INDENT-OFF* */
    return (l2fib_seq_num_t) {
      .swif = *l2fib_swif_seq_num (sw_if_index),
      .bd = bd_config->seq_num,
    };
    /* *INDENT-ON* */
  }
  
  /**
   * Add an entry to the l2fib.
   * If the entry already exists then overwrite it
   */
  void
  l2fib_add_entry (const u8 * mac, u32 bd_index,
  		 u32 sw_if_index, l2fib_entry_result_flags_t flags)
  {
    l2fib_entry_key_t key;
    l2fib_entry_result_t result;
    __attribute__ ((unused)) u32 bucket_contents;
    l2fib_main_t *fm = &l2fib_main;
    l2learn_main_t *lm = &l2learn_main;
    BVT (clib_bihash_kv) kv;
  
    /* set up key */
    key.raw = l2fib_make_key (mac, bd_index);
  
    /* check if entry already exist */
    if (BV (clib_bihash_search) (&fm->mac_table, &kv, &kv))
      {
        /* decrement counter if overwriting a learned mac  */
        result.raw = kv.value;
        if ((!l2fib_entry_result_is_set_AGE_NOT (&result))
  	  && (lm->global_learn_count))
  	lm->global_learn_count--;
      }
  
    /* set up result */
    result.raw = 0;		/* clear all fields */
    result.fields.sw_if_index = sw_if_index;
    result.fields.flags = flags;
  
    /* no aging for provisioned entry */
    l2fib_entry_result_set_AGE_NOT (&result);
  
    kv.key = key.raw;
    kv.value = result.raw;
  
    BV (clib_bihash_add_del) (&fm->mac_table, &kv, 1 /* is_add */ );
  }
  
  /**
   * Add an entry to the L2FIB.
   * The CLI format is:
   *    l2fib add <mac> <bd> <intf> [static] [bvi]
   *    l2fib add <mac> <bd> filter
   * Note that filter and bvi entries are always static
   */
  static clib_error_t *
  l2fib_add (vlib_main_t * vm,
  	   unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    bd_main_t *bdm = &bd_main;
    vnet_main_t *vnm = vnet_get_main ();
    clib_error_t *error = 0;
    u8 mac[6];
    u32 bd_id;
    u32 bd_index;
    u32 sw_if_index = ~0;
    uword *p;
    l2fib_entry_result_flags_t flags;
  
    flags = L2FIB_ENTRY_RESULT_FLAG_NONE;
  
    if (!unformat (input, "%U", unformat_ethernet_address, mac))
      {
        error = clib_error_return (0, "expected mac address `%U'",
  				 format_unformat_error, input);
        goto done;
      }
  
    if (!unformat (input, "%d", &bd_id))
      {
        error = clib_error_return (0, "expected bridge domain ID `%U'",
  				 format_unformat_error, input);
        goto done;
      }
  
    p = hash_get (bdm->bd_index_by_bd_id, bd_id);
    if (!p)
      {
        error = clib_error_return (0, "bridge domain ID %d invalid", bd_id);
        goto done;
      }
    bd_index = p[0];
  
    if (unformat (input, "filter"))
      {
        l2fib_add_filter_entry (mac, bd_index);
        return 0;
      }
  
    if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
      {
        error = clib_error_return (0, "unknown interface `%U'",
  				 format_unformat_error, input);
        goto done;
      }
  
    if (unformat (input, "static"))
      flags |= L2FIB_ENTRY_RESULT_FLAG_STATIC;
    else if (unformat (input, "bvi"))
      flags |= (L2FIB_ENTRY_RESULT_FLAG_STATIC | L2FIB_ENTRY_RESULT_FLAG_BVI);
  
    if (vec_len (l2input_main.configs) <= sw_if_index)
      {
        error = clib_error_return (0, "Interface sw_if_index %d not in L2 mode",
  				 sw_if_index);
        goto done;
      }
  
    l2fib_add_entry (mac, bd_index, sw_if_index, flags);
  
  done:
    return error;
  }
  
  /*?
   * This command adds a MAC Address entry to the L2 FIB table
   * of an existing bridge-domain. The MAC Address can be static
   * or dynamic. This command also allows a filter to be added,
   * such that packets with given MAC Addresses (source mac or
   * destination mac match) are dropped.
   *
   * @cliexpar
   * Example of how to add a dynamic MAC Address entry to the L2 FIB table
   * of a bridge-domain (where 200 is the bridge-domain-id):
   * @cliexcmd{l2fib add 52:54:00:53:18:33 200 GigabitEthernet0/8/0.200}
   * Example of how to add a static MAC Address entry to the L2 FIB table
   * of a bridge-domain (where 200 is the bridge-domain-id):
   * @cliexcmd{l2fib add 52:54:00:53:18:55 200 GigabitEthernet0/8/0.200 static}
   * Example of how to add a filter such that a packet with the given MAC
   * Address will be dropped in a given bridge-domain (where 200 is the
   * bridge-domain-id):
   * @cliexcmd{l2fib add 52:54:00:53:18:77 200 filter}
   * Example of show command of the provisioned MAC Addresses and filters:
   * @cliexstart{show l2fib verbose}
   *     Mac Address     BD Idx           Interface           Index  static  filter  bvi  refresh  timestamp
   *  52:54:00:53:18:33    1      GigabitEthernet0/8/0.200      3       0       0     0      0         0
   *  52:54:00:53:18:55    1      GigabitEthernet0/8/0.200      3       1       0     0      0         0
   *  52:54:00:53:18:77    1                 N/A                -1      1       1     0      0         0
   * 3 l2fib entries
   * @cliexend
  ?*/
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (l2fib_add_cli, static) = {
    .path = "l2fib add",
    .short_help = "l2fib add <mac> <bridge-domain-id> filter | <intf> [static | bvi]",
    .function = l2fib_add,
  };
  /* *INDENT-ON* */
  
  
  static clib_error_t *
  l2fib_test_command_fn (vlib_main_t * vm,
  		       unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    clib_error_t *error = 0;
    u8 mac[6], save_mac[6];
    u32 bd_index = 0;
    u32 sw_if_index = 8;
    u32 is_add = 0;
    u32 is_del = 0;
    u32 is_check = 0;
    u32 count = 1;
    int mac_set = 0;
    int i;
  
    while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
      {
        if (unformat (input, "mac %U", unformat_ethernet_address, mac))
  	mac_set = 1;
        else if (unformat (input, "add"))
  	is_add = 1;
        else if (unformat (input, "del"))
  	is_del = 1;
        else if (unformat (input, "check"))
  	is_check = 1;
        else if (unformat (input, "count %d", &count))
  	;
        else
  	break;
      }
  
    if (mac_set == 0)
      return clib_error_return (0, "mac not set");
  
    if (is_add == 0 && is_del == 0 && is_check == 0)
      return clib_error_return (0,
  			      "noop: pick at least one of (add,del,check)");
  
    clib_memcpy_fast (save_mac, mac, 6);
  
    if (is_add)
      {
        for (i = 0; i < count; i++)
  	{
  	  l2fib_add_entry (mac, bd_index, sw_if_index,
  			   L2FIB_ENTRY_RESULT_FLAG_NONE);
  	  incr_mac_address (mac);
  	}
      }
  
    if (is_check)
      {
        BVT (clib_bihash_kv) kv;
        l2fib_main_t *mp = &l2fib_main;
  
        clib_memcpy_fast (mac, save_mac, 6);
  
        for (i = 0; i < count; i++)
  	{
  	  kv.key = l2fib_make_key (mac, bd_index);
  	  if (BV (clib_bihash_search) (&mp->mac_table, &kv, &kv))
  	    {
  	      clib_warning ("key %U AWOL", format_ethernet_address, mac);
  	      break;
  	    }
  	  incr_mac_address (mac);
  	}
      }
  
    if (is_del)
      {
        clib_memcpy_fast (mac, save_mac, 6);
  
        for (i = 0; i < count; i++)
  	{
  	  l2fib_del_entry (mac, bd_index, 0);
  	  incr_mac_address (mac);
  	}
      }
  
    return error;
  }
  
  /*?
   * The set of '<em>test l2fib</em>' commands allow the L2 FIB table of the default
   * bridge domain (bridge-domain-id of 0) to be modified.
   *
   * @cliexpar
   * @parblock
   * Example of how to add a set of 4 sequential MAC Address entries to L2
   * FIB table of the default bridge-domain:
   * @cliexcmd{test l2fib add mac 52:54:00:53:00:00 count 4}
   *
   * Show the set of 4 sequential MAC Address entries that were added:
   * @cliexstart{show l2fib verbose}
   *     Mac Address     BD Idx           Interface           Index  static  filter  bvi  refresh  timestamp
   * 52:54:00:53:00:00    0       GigabitEthernet0/8/0.300     8       0       0     0      0         0
   * 52:54:00:53:00:01    0       GigabitEthernet0/8/0.300     8       0       0     0      0         0
   * 52:54:00:53:00:03    0       GigabitEthernet0/8/0.300     8       0       0     0      0         0
   * 52:54:00:53:00:02    0       GigabitEthernet0/8/0.300     8       0       0     0      0         0
   * 4 l2fib entries
   * @cliexend
   *
   * Example of how to check that the set of 4 sequential MAC Address
   * entries were added to L2 FIB table of the default
   * bridge-domain. Used a count of 5 to produce an error:
   *
   * @cliexcmd{test l2fib check mac 52:54:00:53:00:00 count 5}
   * The output of the check command is in the log files. Log file
   * location may vary based on your OS and Version:
   *
   * <b><em># tail -f /var/log/messages | grep l2fib_test_command_fn</em></b>
   *
   * Sep  7 17:15:24 localhost vnet[4952]: l2fib_test_command_fn:446: key 52:54:00:53:00:04 AWOL
   *
   * Example of how to delete a set of 4 sequential MAC Address entries
   * from L2 FIB table of the default bridge-domain:
   * @cliexcmd{test l2fib del mac 52:54:00:53:00:00 count 4}
   * @endparblock
  ?*/
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (l2fib_test_command, static) = {
    .path = "test l2fib",
    .short_help = "test l2fib [add|del|check] mac <base-addr> count <nn>",
    .function = l2fib_test_command_fn,
  };
  /* *INDENT-ON* */
  
  
  /**
   * Delete an entry from the l2fib.
   * Return 0 if the entry was deleted, or 1 it was not found or if
   * sw_if_index is non-zero and does not match that in the entry.
   */
  u32
  l2fib_del_entry (const u8 * mac, u32 bd_index, u32 sw_if_index)
  {
    l2fib_entry_result_t result;
    l2fib_main_t *mp = &l2fib_main;
    BVT (clib_bihash_kv) kv;
  
    /* set up key */
    kv.key = l2fib_make_key (mac, bd_index);
  
    if (BV (clib_bihash_search) (&mp->mac_table, &kv, &kv))
      return 1;
  
    result.raw = kv.value;
  
    /*  check if sw_if_index of entry match */
    if ((sw_if_index != 0) && (sw_if_index != result.fields.sw_if_index))
      return 1;
  
    /* decrement counter if dynamically learned mac */
    if ((!l2fib_entry_result_is_set_AGE_NOT (&result)) &&
        (l2learn_main.global_learn_count))
      l2learn_main.global_learn_count--;
  
    /* Remove entry from hash table */
    BV (clib_bihash_add_del) (&mp->mac_table, &kv, 0 /* is_add */ );
    return 0;
  }
  
  /**
   * Delete an entry from the L2FIB.
   * The CLI format is:
   *    l2fib del <mac> <bd-id>
   */
  static clib_error_t *
  l2fib_del (vlib_main_t * vm,
  	   unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    bd_main_t *bdm = &bd_main;
    clib_error_t *error = 0;
    u8 mac[6];
    u32 bd_id;
    u32 bd_index;
    uword *p;
  
    if (!unformat (input, "%U", unformat_ethernet_address, mac))
      {
        error = clib_error_return (0, "expected mac address `%U'",
  				 format_unformat_error, input);
        goto done;
      }
  
    if (!unformat (input, "%d", &bd_id))
      {
        error = clib_error_return (0, "expected bridge domain ID `%U'",
  				 format_unformat_error, input);
        goto done;
      }
  
    p = hash_get (bdm->bd_index_by_bd_id, bd_id);
    if (!p)
      {
        error = clib_error_return (0, "bridge domain ID %d invalid", bd_id);
        goto done;
      }
    bd_index = p[0];
  
    /* Delete the entry */
    if (l2fib_del_entry (mac, bd_index, 0))
      {
        error = clib_error_return (0, "mac entry not found");
        goto done;
      }
  
  done:
    return error;
  }
  
  /*?
   * This command deletes an existing MAC Address entry from the L2 FIB
   * table of an existing bridge-domain.
   *
   * @cliexpar
   * Example of how to delete a MAC Address entry from the L2 FIB table of a bridge-domain (where 200 is the bridge-domain-id):
   * @cliexcmd{l2fib del 52:54:00:53:18:33 200}
  ?*/
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (l2fib_del_cli, static) = {
    .path = "l2fib del",
    .short_help = "l2fib del <mac> <bridge-domain-id> []",
    .function = l2fib_del,
  };
  /* *INDENT-ON* */
  
  /**
      Kick off ager to scan MACs to age/delete MAC entries
  */
  void
  l2fib_start_ager_scan (vlib_main_t * vm)
  {
    uword evt = L2_MAC_AGE_PROCESS_EVENT_ONE_PASS;
  
    /* check if there is at least one bd with mac aging enabled */
    l2_bridge_domain_t *bd_config;
    vec_foreach (bd_config, l2input_main.bd_configs)
    {
      if (bd_config->bd_id != ~0 && bd_config->mac_age != 0)
        {
  	evt = L2_MAC_AGE_PROCESS_EVENT_START;
  	break;
        }
    }
  
    vlib_process_signal_event (vm, l2fib_mac_age_scanner_process_node.index,
  			     evt, 0);
  }
  
  /**
      Flush all non static MACs from an interface
  */
  void
  l2fib_flush_int_mac (vlib_main_t * vm, u32 sw_if_index)
  {
    *l2fib_swif_seq_num (sw_if_index) += 1;
    l2fib_start_ager_scan (vm);
  }
  
  /**
      Flush all non static MACs in a bridge domain
  */
  void
  l2fib_flush_bd_mac (vlib_main_t * vm, u32 bd_index)
  {
    l2_bridge_domain_t *bd_config = l2input_bd_config (bd_index);
    bd_config->seq_num += 1;
    l2fib_start_ager_scan (vm);
  }
  
  /**
      Flush all non static MACs - flushes all valid BDs
  */
  void
  l2fib_flush_all_mac (vlib_main_t * vm)
  {
    l2_bridge_domain_t *bd_config;
    vec_foreach (bd_config, l2input_main.bd_configs)
      if (bd_is_valid (bd_config))
      bd_config->seq_num += 1;
  
    l2fib_start_ager_scan (vm);
  }
  
  
  /**
      Flush MACs, except static ones, associated with an interface
      The CLI format is:
      l2fib flush-mac interface <if-name>
  */
  static clib_error_t *
  l2fib_flush_mac_int (vlib_main_t * vm,
  		     unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    vnet_main_t *vnm = vnet_get_main ();
    clib_error_t *error = 0;
    u32 sw_if_index;
  
    if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
      {
        error = clib_error_return (0, "unknown interface `%U'",
  				 format_unformat_error, input);
        goto done;
      }
  
    l2fib_flush_int_mac (vm, sw_if_index);
  
  done:
    return error;
  }
  
  /**
      Flush all MACs, except static ones
      The CLI format is:
      l2fib flush-mac all
  */
  static clib_error_t *
  l2fib_flush_mac_all (vlib_main_t * vm,
  		     unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    l2fib_flush_all_mac (vm);
    return 0;
  }
  
  /*?
   * This command kick off ager to delete all existing MAC Address entries,
   * except static ones, associated with an interface from the L2 FIB table.
   *
   * @cliexpar
   * Example of how to flush MAC Address entries learned on an interface from the L2 FIB table:
   * @cliexcmd{l2fib flush-mac interface GigabitEthernet2/1/0}
  ?*/
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (l2fib_flush_mac_all_cli, static) = {
    .path = "l2fib flush-mac all",
    .short_help = "l2fib flush-mac all",
    .function = l2fib_flush_mac_all,
  };
  /* *INDENT-ON* */
  
  /*?
   * This command kick off ager to delete all existing MAC Address entries,
   * except static ones, associated with an interface from the L2 FIB table.
   *
   * @cliexpar
   * Example of how to flush MAC Address entries learned on an interface from the L2 FIB table:
   * @cliexcmd{l2fib flush-mac interface GigabitEthernet2/1/0}
  ?*/
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (l2fib_flush_mac_int_cli, static) = {
    .path = "l2fib flush-mac interface",
    .short_help = "l2fib flush-mac interface <if-name>",
    .function = l2fib_flush_mac_int,
  };
  /* *INDENT-ON* */
  
  /**
      Flush bridge-domain MACs except static ones.
      The CLI format is:
      l2fib flush-mac bridge-domain <bd-id>
  */
  static clib_error_t *
  l2fib_flush_mac_bd (vlib_main_t * vm,
  		    unformat_input_t * input, vlib_cli_command_t * cmd)
  {
    bd_main_t *bdm = &bd_main;
    clib_error_t *error = 0;
    u32 bd_index, bd_id;
    uword *p;
  
    if (!unformat (input, "%d", &bd_id))
      {
        error = clib_error_return (0, "expecting bridge-domain id but got `%U'",
  				 format_unformat_error, input);
        goto done;
      }
  
    p = hash_get (bdm->bd_index_by_bd_id, bd_id);
    if (p)
      bd_index = *p;
    else
      return clib_error_return (0, "No such bridge domain %d", bd_id);
  
    l2fib_flush_bd_mac (vm, bd_index);
  
  done:
    return error;
  }
  
  /*?
   * This command kick off ager to delete all existing MAC Address entries,
   * except static ones, in a bridge domain from the L2 FIB table.
   *
   * @cliexpar
   * Example of how to flush MAC Address entries learned in a bridge domain from the L2 FIB table:
   * @cliexcmd{l2fib flush-mac bridge-domain 1000}
  ?*/
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (l2fib_flush_mac_bd_cli, static) = {
    .path = "l2fib flush-mac bridge-domain",
    .short_help = "l2fib flush-mac bridge-domain <bd-id>",
    .function = l2fib_flush_mac_bd,
  };
  /* *INDENT-ON* */
  
  clib_error_t *
  l2fib_sw_interface_up_down (vnet_main_t * vnm, u32 sw_if_index, u32 flags)
  {
    l2_input_config_t *config = l2input_intf_config (sw_if_index);
    if ((flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) == 0 && config->bridge)
      l2fib_flush_int_mac (vnm->vlib_main, sw_if_index);
    return 0;
  }
  
  VNET_SW_INTERFACE_ADMIN_UP_DOWN_FUNCTION (l2fib_sw_interface_up_down);
  
  BVT (clib_bihash) * get_mac_table (void)
  {
    l2fib_main_t *mp = &l2fib_main;
    return &mp->mac_table;
  }
  
  static_always_inline void *
  allocate_mac_evt_buf (u32 client, u32 client_index)
  {
    l2fib_main_t *fm = &l2fib_main;
    vl_api_l2_macs_event_t *mp = vl_msg_api_alloc
      (sizeof (*mp) + (fm->max_macs_in_event * sizeof (vl_api_mac_entry_t)));
    mp->_vl_msg_id = htons (VL_API_L2_MACS_EVENT);
    mp->pid = htonl (client);
    mp->client_index = client_index;
    return mp;
  }
  
  static_always_inline f64
  l2fib_scan (vlib_main_t * vm, f64 start_time, u8 event_only)
  {
    l2fib_main_t *fm = &l2fib_main;
    l2learn_main_t *lm = &l2learn_main;
  
    BVT (clib_bihash) * h = &fm->mac_table;
    int i, j, k;
    f64 last_start = start_time;
    f64 accum_t = 0;
    f64 delta_t = 0;
    u32 evt_idx = 0;
    u32 learn_count = 0;
    u32 client = lm->client_pid;
    u32 cl_idx = lm->client_index;
    vl_api_l2_macs_event_t *mp = 0;
    vl_api_registration_t *reg = 0;
  
    /* Don't scan the l2 fib if it hasn't been instantiated yet */
    if (alloc_arena (h) == 0)
      return 0.0;
  
    if (client)
      {
        mp = allocate_mac_evt_buf (client, cl_idx);
        reg = vl_api_client_index_to_registration (lm->client_index);
      }
  
    for (i = 0; i < h->nbuckets; i++)
      {
        /* allow no more than 20us without a pause */
        delta_t = vlib_time_now (vm) - last_start;
        if (delta_t > 20e-6)
  	{
  	  vlib_process_suspend (vm, 100e-6);	/* suspend for 100 us */
  	  last_start = vlib_time_now (vm);
  	  accum_t += delta_t;
  	}
  
        if (i < (h->nbuckets - 3))
  	{
  	  BVT (clib_bihash_bucket) * b = &h->buckets[i + 3];
  	  CLIB_PREFETCH (b, CLIB_CACHE_LINE_BYTES, LOAD);
  	  b = &h->buckets[i + 1];
  	  if (b->offset)
  	    {
  	      BVT (clib_bihash_value) * v =
  		BV (clib_bihash_get_value) (h, b->offset);
  	      CLIB_PREFETCH (v, CLIB_CACHE_LINE_BYTES, LOAD);
  	    }
  	}
  
        BVT (clib_bihash_bucket) * b = &h->buckets[i];
        if (b->offset == 0)
  	continue;
        BVT (clib_bihash_value) * v = BV (clib_bihash_get_value) (h, b->offset);
        for (j = 0; j < (1 << b->log2_pages); j++)
  	{
  	  for (k = 0; k < BIHASH_KVP_PER_PAGE; k++)
  	    {
  	      if (v->kvp[k].key == ~0ULL && v->kvp[k].value == ~0ULL)
  		continue;
  
  	      l2fib_entry_key_t key = {.raw = v->kvp[k].key };
  	      l2fib_entry_result_t result = {.raw = v->kvp[k].value };
  
  	      if (!l2fib_entry_result_is_set_AGE_NOT (&result))
  		learn_count++;
  
  	      if (client)
  		{
  		  if (PREDICT_FALSE (evt_idx >= fm->max_macs_in_event))
  		    {
  		      /* event message full, send it and start a new one */
  		      if (reg && vl_api_can_send_msg (reg))
  			{
  			  mp->n_macs = htonl (evt_idx);
  			  vl_api_send_msg (reg, (u8 *) mp);
  			  mp = allocate_mac_evt_buf (client, cl_idx);
  			}
  		      else
  			{
  			  if (reg)
  			    clib_warning ("MAC event to pid %d queue stuffed!"
  					  " %d MAC entries lost", client,
  					  evt_idx);
  			}
  		      evt_idx = 0;
  		    }
  
  		  if (l2fib_entry_result_is_set_LRN_EVT (&result))
  		    {
  		      /* copy mac entry to event msg */
  		      clib_memcpy_fast (mp->mac[evt_idx].mac_addr,
  					key.fields.mac, 6);
  		      mp->mac[evt_idx].action =
  			l2fib_entry_result_is_set_LRN_MOV (&result) ?
  			MAC_EVENT_ACTION_MOVE : MAC_EVENT_ACTION_ADD;
  		      mp->mac[evt_idx].sw_if_index =
  			htonl (result.fields.sw_if_index);
  		      /* clear event bits and update mac entry */
  		      l2fib_entry_result_clear_LRN_EVT (&result);
  		      l2fib_entry_result_clear_LRN_MOV (&result);
  		      BVT (clib_bihash_kv) kv;
  		      kv.key = key.raw;
  		      kv.value = result.raw;
  		      BV (clib_bihash_add_del) (&fm->mac_table, &kv, 1);
  		      evt_idx++;
  		      continue;	/* skip aging */
  		    }
  		}
  
  	      if (event_only || l2fib_entry_result_is_set_AGE_NOT (&result))
  		continue;	/* skip aging - static_mac always age_not */
  
  	      /* start aging processing */
  	      u32 bd_index = key.fields.bd_index;
  	      u32 sw_if_index = result.fields.sw_if_index;
  	      u16 sn = l2fib_cur_seq_num (bd_index, sw_if_index).as_u16;
  	      if (result.fields.sn.as_u16 != sn)
  		goto age_out;	/* stale mac */
  
  	      l2_bridge_domain_t *bd_config =
  		vec_elt_at_index (l2input_main.bd_configs, bd_index);
  
  	      if (bd_config->mac_age == 0)
  		continue;	/* skip aging */
  
  	      i16 delta = (u8) (start_time / 60) - result.fields.timestamp;
  	      delta += delta < 0 ? 256 : 0;
  
  	      if (delta < bd_config->mac_age)
  		continue;	/* still valid */
  
  	    age_out:
  	      if (client)
  		{
  		  /* copy mac entry to event msg */
  		  clib_memcpy_fast (mp->mac[evt_idx].mac_addr, key.fields.mac,
  				    6);
  		  mp->mac[evt_idx].action = MAC_EVENT_ACTION_DELETE;
  		  mp->mac[evt_idx].sw_if_index =
  		    htonl (result.fields.sw_if_index);
  		  evt_idx++;
  		}
  	      /* delete mac entry */
  	      BVT (clib_bihash_kv) kv;
  	      kv.key = key.raw;
  	      BV (clib_bihash_add_del) (&fm->mac_table, &kv, 0);
  	      learn_count--;
  	      /*
  	       * Note: we may have just freed the bucket's backing
  	       * storage, so check right here...
  	       */
  	      if (b->offset == 0)
  		goto doublebreak;
  	    }
  	  v++;
  	}
      doublebreak:
        ;
      }
  
    /* keep learn count consistent */
    l2learn_main.global_learn_count = learn_count;
  
    if (mp)
      {
        /*  send any outstanding mac event message else free message buffer */
        if (evt_idx)
  	{
  	  if (reg && vl_api_can_send_msg (reg))
  	    {
  	      mp->n_macs = htonl (evt_idx);
  	      vl_api_send_msg (reg, (u8 *) mp);
  	    }
  	  else
  	    {
  	      if (reg)
  		clib_warning ("MAC event to pid %d queue stuffed!"
  			      " %d MAC entries lost", client, evt_idx);
  	      vl_msg_api_free (mp);
  	    }
  	}
        else
  	vl_msg_api_free (mp);
      }
    return delta_t + accum_t;
  }
  
  static uword
  l2fib_mac_age_scanner_process (vlib_main_t * vm, vlib_node_runtime_t * rt,
  			       vlib_frame_t * f)
  {
    uword event_type, *event_data = 0;
    l2fib_main_t *fm = &l2fib_main;
    l2learn_main_t *lm = &l2learn_main;
    bool enabled = 0;
    f64 start_time, next_age_scan_time = CLIB_TIME_MAX;
  
    while (1)
      {
        if (lm->client_pid)
  	vlib_process_wait_for_event_or_clock (vm, fm->event_scan_delay);
        else if (enabled)
  	{
  	  f64 t = next_age_scan_time - vlib_time_now (vm);
  	  vlib_process_wait_for_event_or_clock (vm, t);
  	}
        else
  	vlib_process_wait_for_event (vm);
  
        event_type = vlib_process_get_events (vm, &event_data);
        vec_reset_length (event_data);
  
        start_time = vlib_time_now (vm);
        enum
        { SCAN_MAC_AGE, SCAN_MAC_EVENT, SCAN_DISABLE } scan = SCAN_MAC_AGE;
  
        switch (event_type)
  	{
  	case ~0:		/* timer expired */
  	  if (lm->client_pid != 0 && start_time < next_age_scan_time)
  	    scan = SCAN_MAC_EVENT;
  	  break;
  
  	case L2_MAC_AGE_PROCESS_EVENT_START:
  	  enabled = 1;
  	  break;
  
  	case L2_MAC_AGE_PROCESS_EVENT_STOP:
  	  enabled = 0;
  	  scan = SCAN_DISABLE;
  	  break;
  
  	case L2_MAC_AGE_PROCESS_EVENT_ONE_PASS:
  	  break;
  
  	default:
  	  ASSERT (0);
  	}
  
        if (scan == SCAN_MAC_EVENT)
  	l2fib_main.evt_scan_duration = l2fib_scan (vm, start_time, 1);
        else
  	{
  	  if (scan == SCAN_MAC_AGE)
  	    l2fib_main.age_scan_duration = l2fib_scan (vm, start_time, 0);
  	  if (scan == SCAN_DISABLE)
  	    {
  	      l2fib_main.age_scan_duration = 0;
  	      l2fib_main.evt_scan_duration = 0;
  	    }
  	  /* schedule next scan */
  	  if (enabled)
  	    next_age_scan_time = start_time + L2FIB_AGE_SCAN_INTERVAL;
  	  else
  	    next_age_scan_time = CLIB_TIME_MAX;
  	}
      }
    return 0;
  }
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (l2fib_mac_age_scanner_process_node) = {
      .function = l2fib_mac_age_scanner_process,
      .type = VLIB_NODE_TYPE_PROCESS,
      .name = "l2fib-mac-age-scanner-process",
  };
  /* *INDENT-ON* */
  
  clib_error_t *
  l2fib_init (vlib_main_t * vm)
  {
    l2fib_main_t *mp = &l2fib_main;
    l2fib_entry_key_t test_key;
    u8 test_mac[6];
  
    mp->vlib_main = vm;
    mp->vnet_main = vnet_get_main ();
  
    /* Create the hash table  */
    BV (clib_bihash_init) (&mp->mac_table, "l2fib mac table",
  			 L2FIB_NUM_BUCKETS, L2FIB_MEMORY_SIZE);
  
    /* verify the key constructor is good, since it is endian-sensitive */
    clib_memset (test_mac, 0, sizeof (test_mac));
    test_mac[0] = 0x11;
    test_key.raw = 0;
    test_key.raw = l2fib_make_key ((u8 *) & test_mac, 0x1234);
    ASSERT (test_key.fields.mac[0] == 0x11);
    ASSERT (test_key.fields.bd_index == 0x1234);
  
    return 0;
  }
  
  VLIB_INIT_FUNCTION (l2fib_init);
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  