src/vnet/vxlan/vxlan.c

/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include <vnet/vxlan/vxlan.h>
#include <vnet/ip/format.h>
#include <vnet/fib/fib_entry.h>
#include <vnet/fib/fib_table.h>
#include <vnet/dpo/receive_dpo.h>
#include <vlib/vlib.h>

/**
 * @file
 * @brief VXLAN.
 *
 * VXLAN provides the features needed to allow L2 bridge domains (BDs)
 * to span multiple servers. This is done by building an L2 overlay on
 * top of an L3 network underlay using VXLAN tunnels.
 *
 * This makes it possible for servers to be co-located in the same data
 * center or be separated geographically as long as they are reachable
 * through the underlay L3 network.
 *
 * You can refer to this kind of L2 overlay bridge domain as a VXLAN
 * (Virtual eXtensible VLAN) segment.
 */


vxlan_main_t vxlan_main;

static u8 * format_decap_next (u8 * s, va_list * args)
{
  u32 next_index = va_arg (*args, u32);

  switch (next_index)
    {
    case VXLAN_INPUT_NEXT_DROP:
      return format (s, "drop");
    case VXLAN_INPUT_NEXT_L2_INPUT:
      return format (s, "l2");
    default:
      return format (s, "index %d", next_index);
    }
  return s;
}

u8 * format_vxlan_tunnel (u8 * s, va_list * args)
{
  vxlan_tunnel_t * t = va_arg (*args, vxlan_tunnel_t *);
  vxlan_main_t * ngm = &vxlan_main;

  s = format (s, "[%d] src %U dst %U vni %d sw_if_index %d ",
              t - ngm->tunnels,
              format_ip46_address, &t->src, IP46_TYPE_ANY,
              format_ip46_address, &t->dst, IP46_TYPE_ANY,
              t->vni, t->sw_if_index);

  if (ip46_address_is_multicast (&t->dst))
    s = format (s, "mcast_sw_if_index %d ", t->mcast_sw_if_index);

  s = format (s, "encap_fib_index %d fib_entry_index %d decap_next %U\n", 
	      t->encap_fib_index, t->fib_entry_index,
	      format_decap_next, t->decap_next_index);
  return s;
}

static u8 * format_vxlan_name (u8 * s, va_list * args)
{
  u32 dev_instance = va_arg (*args, u32);
  return format (s, "vxlan_tunnel%d", dev_instance);
}

static uword dummy_interface_tx (vlib_main_t * vm,
                                 vlib_node_runtime_t * node,
                                 vlib_frame_t * frame)
{
  clib_warning ("you shouldn't be here, leaking buffers...");
  return frame->n_vectors;
}

static clib_error_t *
vxlan_interface_admin_up_down (vnet_main_t * vnm, u32 hw_if_index, u32 flags)
{
  if (flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP)
    vnet_hw_interface_set_flags (vnm, hw_if_index, VNET_HW_INTERFACE_FLAG_LINK_UP);
  else
    vnet_hw_interface_set_flags (vnm, hw_if_index, 0);

  return /* no error */ 0;
}

VNET_DEVICE_CLASS (vxlan_device_class,static) = {
  .name = "VXLAN",
  .format_device_name = format_vxlan_name,
  .format_tx_trace = format_vxlan_encap_trace,
  .tx_function = dummy_interface_tx,
  .admin_up_down_function = vxlan_interface_admin_up_down,
};

static u8 * format_vxlan_header_with_length (u8 * s, va_list * args)
{
  u32 dev_instance = va_arg (*args, u32);
  s = format (s, "unimplemented dev %u", dev_instance);
  return s;
}

VNET_HW_INTERFACE_CLASS (vxlan_hw_class) = {
  .name = "VXLAN",
  .format_header = format_vxlan_header_with_length,
  .build_rewrite = default_build_rewrite,
};

static void
vxlan_tunnel_restack_dpo(vxlan_tunnel_t * t)
{
    dpo_id_t dpo = DPO_INVALID;
    u32 encap_index = ip46_address_is_ip4(&t->dst) ?
        vxlan4_encap_node.index : vxlan6_encap_node.index;
    fib_forward_chain_type_t forw_type = ip46_address_is_ip4(&t->dst) ?
        FIB_FORW_CHAIN_TYPE_UNICAST_IP4 : FIB_FORW_CHAIN_TYPE_UNICAST_IP6;

    fib_entry_contribute_forwarding (t->fib_entry_index, forw_type, &dpo);
    dpo_stack_from_node (encap_index, &t->next_dpo, &dpo);
    dpo_reset(&dpo);
}

static vxlan_tunnel_t *
vxlan_tunnel_from_fib_node (fib_node_t *node)
{
#if (CLIB_DEBUG > 0)
    ASSERT(FIB_NODE_TYPE_VXLAN_TUNNEL == node->fn_type);
#endif
    return ((vxlan_tunnel_t*) (((char*)node) -
			       STRUCT_OFFSET_OF(vxlan_tunnel_t, node)));
}

/**
 * Function definition to backwalk a FIB node -
 * Here we will restack the new dpo of VXLAN DIP to encap node.
 */
static fib_node_back_walk_rc_t
vxlan_tunnel_back_walk (fib_node_t *node,
			fib_node_back_walk_ctx_t *ctx)
{
    vxlan_tunnel_restack_dpo(vxlan_tunnel_from_fib_node(node));
    return (FIB_NODE_BACK_WALK_CONTINUE);
}

/**
 * Function definition to get a FIB node from its index
 */
static fib_node_t*
vxlan_tunnel_fib_node_get (fib_node_index_t index)
{
    vxlan_tunnel_t * t;
    vxlan_main_t * vxm = &vxlan_main;

    t = pool_elt_at_index(vxm->tunnels, index);

    return (&t->node);
}

/**
 * Function definition to inform the FIB node that its last lock has gone.
 */
static void
vxlan_tunnel_last_lock_gone (fib_node_t *node)
{
    /*
     * The VXLAN tunnel is a root of the graph. As such
     * it never has children and thus is never locked.
     */
    ASSERT(0);
}

/*
 * Virtual function table registered by VXLAN tunnels
 * for participation in the FIB object graph.
 */
const static fib_node_vft_t vxlan_vft = {
    .fnv_get = vxlan_tunnel_fib_node_get,
    .fnv_last_lock = vxlan_tunnel_last_lock_gone,
    .fnv_back_walk = vxlan_tunnel_back_walk,
};


#define foreach_copy_field                      \
_(vni)                                          \
_(mcast_sw_if_index)                            \
_(encap_fib_index)                              \
_(decap_next_index)                             \
_(src)                                          \
_(dst)

static int vxlan4_rewrite (vxlan_tunnel_t * t)
{
  u8 *rw = 0;
  ip4_header_t * ip0;
  ip4_vxlan_header_t * h0;
  int len = sizeof (*h0);

  vec_validate_aligned (rw, len-1, CLIB_CACHE_LINE_BYTES);

  h0 = (ip4_vxlan_header_t *) rw;

  /* Fixed portion of the (outer) ip4 header */
  ip0 = &h0->ip4;
  ip0->ip_version_and_header_length = 0x45;
  ip0->ttl = 254;
  ip0->protocol = IP_PROTOCOL_UDP;

  /* we fix up the ip4 header length and checksum after-the-fact */
  ip0->src_address.as_u32 = t->src.ip4.as_u32;
  ip0->dst_address.as_u32 = t->dst.ip4.as_u32;
  ip0->checksum = ip4_header_checksum (ip0);

  /* UDP header, randomize src port on something, maybe? */
  h0->udp.src_port = clib_host_to_net_u16 (4789);
  h0->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_vxlan);

  /* VXLAN header */
  vnet_set_vni_and_flags(&h0->vxlan, t->vni);

  t->rewrite = rw;
  return (0);
}

static int vxlan6_rewrite (vxlan_tunnel_t * t)
{
  u8 *rw = 0;
  ip6_header_t * ip0;
  ip6_vxlan_header_t * h0;
  int len = sizeof (*h0);

  vec_validate_aligned (rw, len-1, CLIB_CACHE_LINE_BYTES);

  h0 = (ip6_vxlan_header_t *) rw;

  /* Fixed portion of the (outer) ip6 header */
  ip0 = &h0->ip6;
  ip0->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32(6 << 28);
  ip0->hop_limit = 255;
  ip0->protocol = IP_PROTOCOL_UDP;

  ip0->src_address.as_u64[0] = t->src.ip6.as_u64[0];
  ip0->src_address.as_u64[1] = t->src.ip6.as_u64[1];
  ip0->dst_address.as_u64[0] = t->dst.ip6.as_u64[0];
  ip0->dst_address.as_u64[1] = t->dst.ip6.as_u64[1];

  /* UDP header, randomize src port on something, maybe? */
  h0->udp.src_port = clib_host_to_net_u16 (4789);
  h0->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_vxlan);

  /* VXLAN header */
  vnet_set_vni_and_flags(&h0->vxlan, t->vni);

  t->rewrite = rw;
  return (0);
}

static int vxlan_check_decap_next(vxlan_main_t * vxm, u32 is_ip6, u32 decap_next_index)
{
  vlib_main_t * vm = vxm->vlib_main;
  vlib_node_runtime_t *r;

  if(!is_ip6)
    {
      r = vlib_node_get_runtime (vm, vxlan4_input_node.index);
      if(decap_next_index >= r->n_next_nodes)
	return 1;
    }
  else
    {
      r = vlib_node_get_runtime (vm, vxlan6_input_node.index);
      if(decap_next_index >= r->n_next_nodes)
	return 1;
    }

  return 0;
}

static uword
vtep_addr_ref(ip46_address_t *ip)
{
	if (!ip46_address_is_ip4(ip))
		return 1; /* always create */
	uword *pvtep = hash_get (vxlan_main.vtep4, ip->ip4.as_u32);
	if (pvtep) 
		return ++pvtep[0];
	hash_set (vxlan_main.vtep4, ip->ip4.as_u32, 1);
	return 1;
}

static uword
vtep_addr_unref(ip46_address_t *ip)
{
	if (!ip46_address_is_ip4(ip))
		return 0; /* alwways destroy */
	uword *pvtep = hash_get (vxlan_main.vtep4, ip->ip4.as_u32);
        ASSERT(pvtep);
	if (!(--pvtep[0]))
		hash_unset (vxlan_main.vtep4, ip->ip4.as_u32);
	return pvtep[0];
}

static
mcast_remote_t *
mcast_ep_get(ip46_address_t * ip)
{
        ASSERT(ip46_address_is_multicast(ip));
	uword * ep_idx = hash_get_mem (vxlan_main.mcast_ep_by_ip, ip);
        ASSERT(ep_idx);
	return pool_elt_at_index(vxlan_main.mcast_eps, *ep_idx);
}

static void
mcast_ep_add(mcast_remote_t * new_ep)
{
	mcast_remote_t * ep;

	pool_get_aligned (vxlan_main.mcast_eps, ep, CLIB_CACHE_LINE_BYTES);
	*ep = *new_ep;
	hash_set_mem (vxlan_main.mcast_ep_by_ip, &ep->ip, ep - vxlan_main.mcast_eps);
}

static void
mcast_ep_remove(mcast_remote_t * ep)
{
	hash_unset_mem (vxlan_main.mcast_ep_by_ip, &ep->ip);
	pool_put (vxlan_main.mcast_eps, ep);
}

static void
ip46_multicast_ethernet_address(u8 * ethernet_address, ip46_address_t * ip) {
          if (ip46_address_is_ip4(ip))
              ip4_multicast_ethernet_address(ethernet_address, &ip->ip4);
          else
              ip6_multicast_ethernet_address(ethernet_address, ip->ip6.as_u32[0]);
}

int vnet_vxlan_add_del_tunnel 
(vnet_vxlan_add_del_tunnel_args_t *a, u32 * sw_if_indexp)
{
  vxlan_main_t * vxm = &vxlan_main;
  vxlan_tunnel_t *t = 0;
  vnet_main_t * vnm = vxm->vnet_main;
  uword * p;
  u32 hw_if_index = ~0;
  u32 sw_if_index = ~0;
  int rv;
  vxlan4_tunnel_key_t key4;
  vxlan6_tunnel_key_t key6;
  u32 is_ip6 = a->is_ip6;

  if (!is_ip6)
    {
      key4.src = a->dst.ip4.as_u32; /* decap src in key is encap dst in config */
      key4.vni = clib_host_to_net_u32 (a->vni << 8);
      p = hash_get (vxm->vxlan4_tunnel_by_key, key4.as_u64);
    } 
  else 
    {
      key6.src.as_u64[0] = a->dst.ip6.as_u64[0];
      key6.src.as_u64[1] = a->dst.ip6.as_u64[1];
      key6.vni = clib_host_to_net_u32 (a->vni << 8);
      p = hash_get_mem (vxm->vxlan6_tunnel_by_key, &key6);
    }
  
  if (a->is_add)
    {
      l2input_main_t * l2im = &l2input_main;

      /* adding a tunnel: tunnel must not already exist */
      if (p)
        return VNET_API_ERROR_TUNNEL_EXIST;

      /*if not set explicitly, default to l2 */
      if(a->decap_next_index == ~0)
	a->decap_next_index = VXLAN_INPUT_NEXT_L2_INPUT;
      if (vxlan_check_decap_next(vxm, is_ip6, a->decap_next_index))
	  return VNET_API_ERROR_INVALID_DECAP_NEXT;

      pool_get_aligned (vxm->tunnels, t, CLIB_CACHE_LINE_BYTES);
      memset (t, 0, sizeof (*t));
      
      /* copy from arg structure */
#define _(x) t->x = a->x;
      foreach_copy_field;
#undef _
      
      /* copy the key */
      if (is_ip6)
        {
          t->key6 = clib_mem_alloc (sizeof(vxlan6_tunnel_key_t));
          clib_memcpy (t->key6, &key6, sizeof(key6));
        }
      else
        {
          t->key4 = 0; /* not yet used */
        }

      if (!is_ip6) 
        rv = vxlan4_rewrite (t);
      else
	rv = vxlan6_rewrite (t);

      if (rv)
        {
          pool_put (vxm->tunnels, t);
          return rv;
        }

      if (!is_ip6)
	hash_set (vxm->vxlan4_tunnel_by_key, key4.as_u64, t - vxm->tunnels);
      else
        hash_set_mem (vxm->vxlan6_tunnel_by_key, t->key6, t - vxm->tunnels);

      vnet_hw_interface_t * hi;
      if (vec_len (vxm->free_vxlan_tunnel_hw_if_indices) > 0)
        {
	  vnet_interface_main_t * im = &vnm->interface_main;
          hw_if_index = vxm->free_vxlan_tunnel_hw_if_indices
            [vec_len (vxm->free_vxlan_tunnel_hw_if_indices)-1];
          _vec_len (vxm->free_vxlan_tunnel_hw_if_indices) -= 1;
          
          hi = vnet_get_hw_interface (vnm, hw_if_index);
          hi->dev_instance = t - vxm->tunnels;
          hi->hw_instance = hi->dev_instance;

	  /* clear old stats of freed tunnel before reuse */
	  sw_if_index = hi->sw_if_index;
	  vnet_interface_counter_lock(im);
	  vlib_zero_combined_counter 
	    (&im->combined_sw_if_counters[VNET_INTERFACE_COUNTER_TX], sw_if_index);
	  vlib_zero_combined_counter 
	    (&im->combined_sw_if_counters[VNET_INTERFACE_COUNTER_RX], sw_if_index);
	  vlib_zero_simple_counter 
	    (&im->sw_if_counters[VNET_INTERFACE_COUNTER_DROP], sw_if_index);
	  vnet_interface_counter_unlock(im);
        }
      else 
        {
          hw_if_index = vnet_register_interface
            (vnm, vxlan_device_class.index, t - vxm->tunnels,
             vxlan_hw_class.index, t - vxm->tunnels);
          hi = vnet_get_hw_interface (vnm, hw_if_index);
        }
      
      t->hw_if_index = hw_if_index;
      t->sw_if_index = sw_if_index = hi->sw_if_index;
      
      vec_validate_init_empty (vxm->tunnel_index_by_sw_if_index, sw_if_index, ~0);
      vxm->tunnel_index_by_sw_if_index[sw_if_index] = t - vxm->tunnels;

      /* setup l2 input config with l2 feature and bd 0 to drop packet */
      vec_validate (l2im->configs, sw_if_index);
      l2im->configs[sw_if_index].feature_bitmap = L2INPUT_FEAT_DROP;
      l2im->configs[sw_if_index].bd_index = 0;
      
      vnet_sw_interface_set_flags (vnm, sw_if_index, 
                                   VNET_SW_INTERFACE_FLAG_ADMIN_UP);
      fib_node_init(&t->node, FIB_NODE_TYPE_VXLAN_TUNNEL);
      fib_prefix_t tun_dst_pfx;
      u32 encap_index = !is_ip6 ?
          vxlan4_encap_node.index : vxlan6_encap_node.index;
      vnet_flood_class_t flood_class = VNET_FLOOD_CLASS_TUNNEL_NORMAL;

      fib_prefix_from_ip46_addr(&t->dst, &tun_dst_pfx);
      if (!ip46_address_is_multicast(&t->dst))
        {
          /* Unicast tunnel -
           * source the FIB entry for the tunnel's destination
           * and become a child thereof. The tunnel will then get poked
           * when the forwarding for the entry updates, and the tunnel can
           * re-stack accordingly
           */
	  vtep_addr_ref(&t->src);
          t->fib_entry_index = fib_table_entry_special_add
            (t->encap_fib_index, &tun_dst_pfx, FIB_SOURCE_RR,
	     FIB_ENTRY_FLAG_NONE, ADJ_INDEX_INVALID);
          t->sibling_index = fib_entry_child_add
            (t->fib_entry_index, FIB_NODE_TYPE_VXLAN_TUNNEL, t - vxm->tunnels);
          vxlan_tunnel_restack_dpo(t);
	} 
      else
        {
 	  /* Multicast tunnel -
	   * as the same mcast group can be used for mutiple mcast tunnels
	   * with different VNIs, create the output fib adjecency only if
	   * it does not already exist
	   */
          fib_protocol_t fp = (is_ip6) ? FIB_PROTOCOL_IP6 : FIB_PROTOCOL_IP4;
          dpo_id_t dpo = DPO_INVALID;
	  dpo_proto_t dproto = fib_proto_to_dpo(fp);

	  if (vtep_addr_ref(&t->dst) == 1)
	    {
               u8 mcast_mac[6];

               ip46_multicast_ethernet_address(mcast_mac, &t->dst);
               receive_dpo_add_or_lock(dproto, ~0, NULL, &dpo);
	       mcast_remote_t new_ep = {
	         .ip = t->dst,
		 .mcast_adj_index = adj_rewrite_add_and_lock
                   (fp, fib_proto_to_link(fp), a->mcast_sw_if_index, mcast_mac),
                 /* Add VRF local mcast adj. */
                 .fib_entry_index = fib_table_entry_special_dpo_add
                   (t->encap_fib_index, &tun_dst_pfx,
                    FIB_SOURCE_SPECIAL, FIB_ENTRY_FLAG_NONE, &dpo)
		   };
	       mcast_ep_add(&new_ep);
	       dpo_reset(&dpo);
	    }
          /* Stack shared mcast dst mac addr rewrite on encap */
          dpo_set (&dpo, DPO_ADJACENCY, dproto,
	    mcast_ep_get(&t->dst)->mcast_adj_index);
          dpo_stack_from_node (encap_index, &t->next_dpo, &dpo);
          dpo_reset (&dpo);
	  flood_class = VNET_FLOOD_CLASS_TUNNEL_MASTER;
	}

      /* Set vxlan tunnel output node */
      hi->output_node_index = encap_index;

      vnet_get_sw_interface (vnet_get_main(), sw_if_index)->flood_class = flood_class;
    }
  else
    {
      /* deleting a tunnel: tunnel must exist */
      if (!p)
        return VNET_API_ERROR_NO_SUCH_ENTRY;

      t = pool_elt_at_index (vxm->tunnels, p[0]);

      vnet_sw_interface_set_flags (vnm, t->sw_if_index, 0 /* down */);
      /* make sure tunnel is removed from l2 bd or xconnect */
      set_int_l2_mode(vxm->vlib_main, vnm, MODE_L3, t->sw_if_index, 0, 0, 0, 0);
      vec_add1 (vxm->free_vxlan_tunnel_hw_if_indices, t->hw_if_index);

      vxm->tunnel_index_by_sw_if_index[t->sw_if_index] = ~0;

      if (!is_ip6)
        hash_unset (vxm->vxlan4_tunnel_by_key, key4.as_u64);
      else
        {
	  hash_unset_mem (vxm->vxlan6_tunnel_by_key, t->key6);
	  clib_mem_free (t->key6);
	}

      if (!ip46_address_is_multicast(&t->dst))
        {
	  vtep_addr_unref(&a->src);
	  fib_entry_child_remove(t->fib_entry_index, t->sibling_index);
	  fib_table_entry_delete_index(t->fib_entry_index, FIB_SOURCE_RR);
        }
      else if (vtep_addr_unref(&t->dst) == 0)
        {
	  mcast_remote_t* ep = mcast_ep_get(&t->dst);
	  adj_unlock(ep->mcast_adj_index);
	  fib_table_entry_delete_index(ep->fib_entry_index, FIB_SOURCE_SPECIAL);
	  mcast_ep_remove(ep);
        }

      fib_node_deinit(&t->node);
      vec_free (t->rewrite);
      pool_put (vxm->tunnels, t);
    }

  if (sw_if_indexp)
      *sw_if_indexp = sw_if_index;

  return 0;
}

static u32 fib4_index_from_fib_id (u32 fib_id)
{
  ip4_main_t * im = &ip4_main;
  uword * p;

  p = hash_get (im->fib_index_by_table_id, fib_id);
  if (!p)
    return ~0;

  return p[0];
}

static u32 fib6_index_from_fib_id (u32 fib_id)
{
  ip6_main_t * im = &ip6_main;
  uword * p;

  p = hash_get (im->fib_index_by_table_id, fib_id);
  if (!p)
    return ~0;

  return p[0];
}

static uword get_decap_next_for_node(u32 node_index, u32 ipv4_set)
{
  vxlan_main_t * vxm = &vxlan_main;
  vlib_main_t * vm = vxm->vlib_main;
  uword next_index = ~0;

  if (ipv4_set)
    {
      next_index = vlib_node_add_next (vm, vxlan4_input_node.index, node_index);
    }
  else
    {
      next_index = vlib_node_add_next (vm, vxlan6_input_node.index, node_index);
    }

  return next_index;
}

static uword unformat_decap_next (unformat_input_t * input, va_list * args)
{
  u32 * result = va_arg (*args, u32 *);
  u32 ipv4_set = va_arg (*args, int);
  vxlan_main_t * vxm = &vxlan_main;
  vlib_main_t * vm = vxm->vlib_main;
  u32 node_index;
  u32 tmp;

  if (unformat (input, "l2"))
    *result = VXLAN_INPUT_NEXT_L2_INPUT;
  else if (unformat (input, "node %U", unformat_vlib_node, vm, &node_index))
    *result = get_decap_next_for_node(node_index, ipv4_set);
  else if (unformat (input, "%d", &tmp))
    *result = tmp;
  else
    return 0;
  return 1;
}

static clib_error_t *
vxlan_add_del_tunnel_command_fn (vlib_main_t * vm,
                                   unformat_input_t * input,
                                   vlib_cli_command_t * cmd)
{
  unformat_input_t _line_input, * line_input = &_line_input;
  ip46_address_t src , dst;
  u8 is_add = 1;
  u8 src_set = 0;
  u8 dst_set = 0;
  u8 grp_set = 0;
  u8 ipv4_set = 0;
  u8 ipv6_set = 0;
  u32 encap_fib_index = 0;
  u32 mcast_sw_if_index = ~0;
  u32 decap_next_index = VXLAN_INPUT_NEXT_L2_INPUT;
  u32 vni = 0;
  u32 tmp;
  int rv;
  vnet_vxlan_add_del_tunnel_args_t _a, * a = &_a;
  u32 tunnel_sw_if_index;

  /* Cant "universally zero init" (={0}) due to GCC bug 53119 */
  memset(&src, 0, sizeof src);
  memset(&dst, 0, sizeof dst);

  /* Get a line of input. */
  if (! unformat_user (input, unformat_line_input, line_input))
    return 0;

  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT) {
    if (unformat (line_input, "del"))
      {
        is_add = 0;
      }
    else if (unformat (line_input, "src %U",
                       unformat_ip4_address, &src.ip4))
      {
        src_set = 1;
        ipv4_set = 1;
      }
    else if (unformat (line_input, "dst %U",
                       unformat_ip4_address, &dst.ip4))
      {
        dst_set = 1;
        ipv4_set = 1;
      }
    else if (unformat (line_input, "src %U", 
                       unformat_ip6_address, &src.ip6))
      {
        src_set = 1;
        ipv6_set = 1;
      }
    else if (unformat (line_input, "dst %U",
                       unformat_ip6_address, &dst.ip6))
      {
        dst_set = 1;
        ipv6_set = 1;
      }
    else if (unformat (line_input, "group %U %U",
                       unformat_ip4_address, &dst.ip4,
		       unformat_vnet_sw_interface,
		       vnet_get_main(), &mcast_sw_if_index))
      {
        grp_set = dst_set = 1;
        ipv4_set = 1;
      }
    else if (unformat (line_input, "group %U %U",
                       unformat_ip6_address, &dst.ip6,
		       unformat_vnet_sw_interface,
		       vnet_get_main(), &mcast_sw_if_index))
      {
        grp_set = dst_set = 1;
        ipv6_set = 1;
      }
    else if (unformat (line_input, "encap-vrf-id %d", &tmp))
      {
        if (ipv6_set)
          encap_fib_index = fib6_index_from_fib_id (tmp);
        else
          encap_fib_index = fib4_index_from_fib_id (tmp);
        if (encap_fib_index == ~0)
          return clib_error_return (0, "nonexistent encap-vrf-id %d", tmp);
      }
    else if (unformat (line_input, "decap-next %U", unformat_decap_next, 
                       &decap_next_index, ipv4_set))
      ;
    else if (unformat (line_input, "vni %d", &vni))
      {
        if (vni >> 24)  
          return clib_error_return (0, "vni %d out of range", vni);
      }
    else 
      return clib_error_return (0, "parse error: '%U'", 
                                format_unformat_error, line_input);
  }

  unformat_free (line_input);

  if (src_set == 0)
    return clib_error_return (0, "tunnel src address not specified");

  if (dst_set == 0)
    return clib_error_return (0, "tunnel dst address not specified");

  if (grp_set && !ip46_address_is_multicast(&dst))
    return clib_error_return (0, "tunnel group address not multicast");

  if (grp_set == 0 && ip46_address_is_multicast(&dst))
    return clib_error_return (0, "dst address must be unicast");

  if (grp_set && mcast_sw_if_index == ~0)
    return clib_error_return (0, "tunnel nonexistent multicast device");

  if (ipv4_set && ipv6_set)
    return clib_error_return (0, "both IPv4 and IPv6 addresses specified");

  if (ip46_address_cmp(&src, &dst) == 0)
    return clib_error_return (0, "src and dst addresses are identical");

  if (decap_next_index == ~0)
    return clib_error_return (0, "next node not found");

  if (vni == 0)
    return clib_error_return (0, "vni not specified");

  memset (a, 0, sizeof (*a));

  a->is_add = is_add;
  a->is_ip6 = ipv6_set;

#define _(x) a->x = x;
  foreach_copy_field;
#undef _
  
  rv = vnet_vxlan_add_del_tunnel (a, &tunnel_sw_if_index);

  switch(rv)
    {
    case 0:
      if (is_add)
        vlib_cli_output(vm, "%U\n", format_vnet_sw_if_index_name, 
			vnet_get_main(), tunnel_sw_if_index);
      break;

    case VNET_API_ERROR_TUNNEL_EXIST:
      return clib_error_return (0, "tunnel already exists...");

    case VNET_API_ERROR_NO_SUCH_ENTRY:
      return clib_error_return (0, "tunnel does not exist...");

    default:
      return clib_error_return 
        (0, "vnet_vxlan_add_del_tunnel returned %d", rv);
    }

  return 0;
}

/*?
 * Add or delete a VXLAN Tunnel.
 *
 * VXLAN provides the features needed to allow L2 bridge domains (BDs)
 * to span multiple servers. This is done by building an L2 overlay on
 * top of an L3 network underlay using VXLAN tunnels.
 *
 * This makes it possible for servers to be co-located in the same data
 * center or be separated geographically as long as they are reachable
 * through the underlay L3 network.
 *
 * You can refer to this kind of L2 overlay bridge domain as a VXLAN
 * (Virtual eXtensible VLAN) segment.
 *
 * @cliexpar
 * Example of how to create a VXLAN Tunnel:
 * @cliexcmd{create vxlan tunnel src 10.0.3.1 dst 10.0.3.3 vni 13 encap-vrf-id 7}
 * Example of how to delete a VXLAN Tunnel:
 * @cliexcmd{create vxlan tunnel src 10.0.3.1 dst 10.0.3.3 vni 13 del}
 ?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (create_vxlan_tunnel_command, static) = {
  .path = "create vxlan tunnel",
  .short_help = 
  "create vxlan tunnel src <local-vtep-addr>"
  " {dst <remote-vtep-addr>|group <mcast-vtep-addr> <intf-name>} vni <nn>"
  " [encap-vrf-id <nn>] [decap-next [l2|node <name>]] [del]",
  .function = vxlan_add_del_tunnel_command_fn,
};
/* *INDENT-ON* */

static clib_error_t *
show_vxlan_tunnel_command_fn (vlib_main_t * vm,
                                unformat_input_t * input,
                                vlib_cli_command_t * cmd)
{
  vxlan_main_t * vxm = &vxlan_main;
  vxlan_tunnel_t * t;
  
  if (pool_elts (vxm->tunnels) == 0)
    vlib_cli_output (vm, "No vxlan tunnels configured...");

  pool_foreach (t, vxm->tunnels,
  ({
    vlib_cli_output (vm, "%U", format_vxlan_tunnel, t);
  }));
  
  return 0;
}

/*?
 * Display all the VXLAN Tunnel entries.
 *
 * @cliexpar
 * Example of how to display the VXLAN Tunnel entries:
 * @cliexstart{show vxlan tunnel}
 * [0] src 10.0.3.1 dst 10.0.3.3 vni 13 encap_fib_index 0 sw_if_index 5 decap_next l2
 * @cliexend
 ?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (show_vxlan_tunnel_command, static) = {
    .path = "show vxlan tunnel",
    .short_help = "show vxlan tunnel",
    .function = show_vxlan_tunnel_command_fn,
};
/* *INDENT-ON* */


clib_error_t *vxlan_init (vlib_main_t *vm)
{
  vxlan_main_t * vxm = &vxlan_main;
  
  vxm->vnet_main = vnet_get_main();
  vxm->vlib_main = vm;

  /* initialize the ip6 hash */
  vxm->vxlan6_tunnel_by_key = hash_create_mem(0,
        sizeof(vxlan6_tunnel_key_t),
        sizeof(uword));
  vxm->mcast_ep_by_ip = hash_create_mem(0,
        sizeof(ip46_address_t),
	sizeof(uword));

  udp_register_dst_port (vm, UDP_DST_PORT_vxlan, 
                         vxlan4_input_node.index, /* is_ip4 */ 1);
  udp_register_dst_port (vm, UDP_DST_PORT_vxlan6,
                         vxlan6_input_node.index, /* is_ip4 */ 0);

  fib_node_register_type(FIB_NODE_TYPE_VXLAN_TUNNEL, &vxlan_vft);

  return 0;
}

VLIB_INIT_FUNCTION(vxlan_init);