vxlan.c

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/*
 * 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/mfib/mfib_table.h>
#include <vnet/adj/adj_mcast.h>
#include <vnet/interface.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)
{
  u32 hw_flags = (flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) ?
    VNET_HW_INTERFACE_FLAG_LINK_UP : 0;
  vnet_hw_interface_set_flags (vnm, hw_if_index, hw_flags);

  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
vxlan_rewrite (vxlan_tunnel_t * t, bool is_ip6)
{
  union {
    ip4_vxlan_header_t * h4;
    ip6_vxlan_header_t * h6;
    u8 *rw;
  } r = { .rw = 0 };
  int len = is_ip6 ? sizeof *r.h6 : sizeof *r.h4;

  vec_validate_aligned (r.rw, len-1, CLIB_CACHE_LINE_BYTES);

  udp_header_t * udp;
  vxlan_header_t * vxlan;
  /* Fixed portion of the (outer) ip header */
  if (!is_ip6) 
    {
      ip4_header_t * ip = &r.h4->ip4;
      udp = &r.h4->udp, vxlan = &r.h4->vxlan;
      ip->ip_version_and_header_length = 0x45;
      ip->ttl = 254;
      ip->protocol = IP_PROTOCOL_UDP;
    
      ip->src_address = t->src.ip4;
      ip->dst_address = t->dst.ip4;

      /* we fix up the ip4 header length and checksum after-the-fact */
      ip->checksum = ip4_header_checksum (ip);
    }
  else
    {
      ip6_header_t * ip = &r.h6->ip6;
      udp = &r.h6->udp, vxlan = &r.h6->vxlan;
      ip->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32(6 << 28);
      ip->hop_limit = 255;
      ip->protocol = IP_PROTOCOL_UDP;
    
      ip->src_address = t->src.ip6;
      ip->dst_address = t->dst.ip6;
    }

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

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

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

static bool
vxlan_decap_next_is_valid (vxlan_main_t * vxm, u32 is_ip6, u32 decap_next_index)
{
  vlib_main_t * vm = vxm->vlib_main;
  u32 input_idx = (!is_ip6) ? vxlan4_input_node.index : vxlan6_input_node.index;
  vlib_node_runtime_t *r = vlib_node_get_runtime (vm, input_idx);

  return decap_next_index < r->n_next_nodes;
}

static void
hash_set_key_copy (uword ** h, void * key, uword v) {
        size_t ksz = hash_header(*h)->user;
        void * copy = clib_mem_alloc (ksz);
        clib_memcpy (copy, key, ksz);
        hash_set_mem (*h, copy, v);
}

static void
hash_unset_key_free (uword ** h, void * key) {
        hash_pair_t * hp = hash_get_pair_mem (*h, key);
        ASSERT (hp);
        key = uword_to_pointer (hp->key, void *);
        hash_unset_mem (*h, key);
        clib_mem_free (key);
}

static uword
vtep_addr_ref(ip46_address_t *ip)
{
        uword *vtep = ip46_address_is_ip4(ip) ?
                         hash_get (vxlan_main.vtep4, ip->ip4.as_u32) :
                         hash_get_mem (vxlan_main.vtep6, &ip->ip6);
        if (vtep) 
                return ++(*vtep);
        ip46_address_is_ip4(ip) ?
                         hash_set (vxlan_main.vtep4, ip->ip4.as_u32, 1) :
                         hash_set_key_copy (&vxlan_main.vtep6, &ip->ip6, 1);
        return 1;
}

static uword
vtep_addr_unref(ip46_address_t *ip)
{
        uword *vtep = ip46_address_is_ip4(ip) ?
                         hash_get (vxlan_main.vtep4, ip->ip4.as_u32) :
                         hash_get_mem (vxlan_main.vtep6, &ip->ip6);
        ASSERT(vtep);
        if (--(*vtep) != 0)
                return *vtep;
        ip46_address_is_ip4(ip) ?
                hash_unset (vxlan_main.vtep4, ip->ip4.as_u32) :
                hash_unset_key_free (&vxlan_main.vtep6, &ip->ip6);
        return 0;
}

typedef CLIB_PACKED(union {
  struct {
    fib_node_index_t mfib_entry_index;
    adj_index_t mcast_adj_index;
  };
  u64 as_u64;
}) mcast_shared_t;

static inline mcast_shared_t
mcast_shared_get(ip46_address_t * ip)
{
        ASSERT(ip46_address_is_multicast(ip));
        uword * p = hash_get_mem (vxlan_main.mcast_shared, ip);
        ASSERT(p);
        return (mcast_shared_t) { .as_u64 = *p };
}

static inline void
mcast_shared_add(ip46_address_t *dst,
                 fib_node_index_t mfei,
                 adj_index_t ai)
{
    mcast_shared_t new_ep = {
        .mcast_adj_index = ai,
        .mfib_entry_index = mfei,
    };

    hash_set_key_copy (&vxlan_main.mcast_shared, dst, new_ep.as_u64);
}

static inline void
mcast_shared_remove(ip46_address_t *dst)
{
    mcast_shared_t ep = mcast_shared_get(dst);

    adj_unlock(ep.mcast_adj_index);
    mfib_table_entry_delete_index(ep.mfib_entry_index,
                                  MFIB_SOURCE_VXLAN);

    hash_unset_key_free (&vxlan_main.mcast_shared, dst);
}

static inline fib_protocol_t
fib_ip_proto(bool is_ip6)
{
  return (is_ip6) ? FIB_PROTOCOL_IP6 : FIB_PROTOCOL_IP4;
}

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 = a->dst.ip6;
      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_decap_next_is_valid(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 _

      rv = vxlan_rewrite (t, is_ip6);
      if (rv)
        {
          pool_put (vxm->tunnels, t);
          return rv;
        }

      /* copy the key */
      if (is_ip6)
        hash_set_key_copy (&vxm->vxlan6_tunnel_by_key, &key6, t - vxm->tunnels);
      else
        hash_set (vxm->vxlan4_tunnel_by_key, key4.as_u64, 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_t * si = vnet_get_sw_interface (vnm, sw_if_index);
      si->flags &= ~VNET_SW_INTERFACE_FLAG_HIDDEN;
      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);
          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 = fib_ip_proto(is_ip6);

          if (vtep_addr_ref(&t->dst) == 1)
          {
              fib_node_index_t mfei;
              adj_index_t ai;
              fib_route_path_t path = {
                  .frp_proto = fib_proto_to_dpo(fp),
                  .frp_addr = zero_addr,
                  .frp_sw_if_index = 0xffffffff,
                  .frp_fib_index = ~0,
                  .frp_weight = 0,
                  .frp_flags = FIB_ROUTE_PATH_LOCAL,
              };
              const mfib_prefix_t mpfx = {
                  .fp_proto = fp,
                  .fp_len = (is_ip6 ? 128 : 32),
                  .fp_grp_addr = tun_dst_pfx.fp_addr,
              };

              /*
               * Setup the (*,G) to receive traffic on the mcast group
               *  - the forwarding interface is for-us
               *  - the accepting interface is that from the API
               */
              mfib_table_entry_path_update(t->encap_fib_index,
                                           &mpfx,
                                           MFIB_SOURCE_VXLAN,
                                           &path,
                                           MFIB_ITF_FLAG_FORWARD);

              path.frp_sw_if_index = a->mcast_sw_if_index;
              path.frp_flags = FIB_ROUTE_PATH_FLAG_NONE;
              mfei = mfib_table_entry_path_update(t->encap_fib_index,
                                                  &mpfx,
                                                  MFIB_SOURCE_VXLAN,
                                                  &path,
                                                  MFIB_ITF_FLAG_ACCEPT);

              /*
               * Create the mcast adjacency to send traffic to the group
               */
              ai = adj_mcast_add_or_lock(fp,
                                         fib_proto_to_link(fp),
                                         a->mcast_sw_if_index);

              /*
               * create a new end-point
               */
              mcast_shared_add(&t->dst, mfei, ai);
          }

          dpo_id_t dpo = DPO_INVALID;
          mcast_shared_t ep = mcast_shared_get(&t->dst);

          /* Stack shared mcast dst mac addr rewrite on encap */
          dpo_set (&dpo, DPO_ADJACENCY_MCAST,
                   fib_proto_to_dpo(fp),
                   ep.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]);

      sw_if_index = t->sw_if_index;
      vnet_sw_interface_set_flags (vnm, t->sw_if_index, 0 /* down */);
      vnet_sw_interface_t * si = vnet_get_sw_interface (vnm, t->sw_if_index);
      si->flags |= VNET_SW_INTERFACE_FLAG_HIDDEN;

      /* 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_key_free (&vxm->vxlan6_tunnel_by_key, &key6);

      if (!ip46_address_is_multicast(&t->dst))
        {
          vtep_addr_unref(&t->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_shared_remove(&t->dst);
        }

      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 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 input_node = (ipv4_set) ? vxlan4_input_node.index :
    vxlan6_input_node.index;

  return vlib_node_add_next (vm, input_node, node_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;
  clib_error_t *error = NULL;

  /* 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))
      {
        encap_fib_index = fib_table_find (fib_ip_proto (ipv6_set), tmp);
        if (encap_fib_index == ~0)
          {
            error = clib_error_return (0, "nonexistent encap-vrf-id %d", tmp);
            goto done;
          }
      }
    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)  
          {
            error = clib_error_return (0, "vni %d out of range", vni);
            goto done;
          }
      }
    else 
      {
        error = clib_error_return (0, "parse error: '%U'",
                                   format_unformat_error, line_input);
        goto done;
      }
  }

  if (src_set == 0)
    {
      error = clib_error_return (0, "tunnel src address not specified");
      goto done;
    }

  if (dst_set == 0)
    {
      error = clib_error_return (0, "tunnel dst address not specified");
      goto done;
    }

  if (grp_set && !ip46_address_is_multicast(&dst))
    {
      error = clib_error_return (0, "tunnel group address not multicast");
      goto done;
    }

  if (grp_set == 0 && ip46_address_is_multicast(&dst))
    {
      error = clib_error_return (0, "dst address must be unicast");
      goto done;
    }

  if (grp_set && mcast_sw_if_index == ~0)
    {
      error = clib_error_return (0, "tunnel nonexistent multicast device");
      goto done;
    }

  if (ipv4_set && ipv6_set)
    {
      error = clib_error_return (0, "both IPv4 and IPv6 addresses specified");
      goto done;
    }

  if (ip46_address_cmp(&src, &dst) == 0)
    {
      error = clib_error_return (0, "src and dst addresses are identical");
      goto done;
    }

  if (decap_next_index == ~0)
    {
      error = clib_error_return (0, "next node not found");
      goto done;
    }

  if (vni == 0)
    {
      error = clib_error_return (0, "vni not specified");
      goto done;
    }

  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:
      error = clib_error_return (0, "tunnel already exists...");
      goto done;

    case VNET_API_ERROR_NO_SUCH_ENTRY:
      error = clib_error_return (0, "tunnel does not exist...");
      goto done;

    default:
      error = clib_error_return
        (0, "vnet_vxlan_add_del_tunnel returned %d", rv);
      goto done;
    }

done:
  unformat_free (line_input);

  return error;
}

/*?
 * 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* */


void vnet_int_vxlan_bypass_mode (u32 sw_if_index,
                                 u8 is_ip6,
                                 u8 is_enable)
{
  if (is_ip6)
    vnet_feature_enable_disable ("ip6-unicast", "ip6-vxlan-bypass",
                                 sw_if_index, is_enable, 0, 0);
  else
    vnet_feature_enable_disable ("ip4-unicast", "ip4-vxlan-bypass",
                                 sw_if_index, is_enable, 0, 0);
}


static clib_error_t *
set_ip_vxlan_bypass (u32 is_ip6,
                     unformat_input_t * input,
                     vlib_cli_command_t * cmd)
{
  unformat_input_t _line_input, * line_input = &_line_input;
  vnet_main_t * vnm = vnet_get_main();
  clib_error_t * error = 0;
  u32 sw_if_index, is_enable;

  sw_if_index = ~0;
  is_enable = 1;

  if (! unformat_user (input, unformat_line_input, line_input))
    return 0;

  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat_user (line_input, unformat_vnet_sw_interface, vnm, &sw_if_index))
          ;
      else if (unformat (line_input, "del"))
        is_enable = 0;
      else
        {
          error = unformat_parse_error (line_input);
          goto done;
        }
    }

  if (~0 == sw_if_index)
    {
      error = clib_error_return (0, "unknown interface `%U'",
                                 format_unformat_error, line_input);
      goto done;
    }

  vnet_int_vxlan_bypass_mode (sw_if_index, is_ip6, is_enable);

 done:
  unformat_free (line_input);

  return error;
}

static clib_error_t *
set_ip4_vxlan_bypass (vlib_main_t * vm,
                      unformat_input_t * input,
                      vlib_cli_command_t * cmd)
{
  return set_ip_vxlan_bypass (0, input, cmd);
}

/*?
 * This command adds the 'ip4-vxlan-bypass' graph node for a given interface. 
 * By adding the IPv4 vxlan-bypass graph node to an interface, the node checks
 *  for and validate input vxlan packet and bypass ip4-lookup, ip4-local, 
 * ip4-udp-lookup nodes to speedup vxlan packet forwarding. This node will 
 * cause extra overhead to for non-vxlan packets which is kept at a minimum.
 *
 * @cliexpar
 * @parblock
 * Example of graph node before ip4-vxlan-bypass is enabled:
 * @cliexstart{show vlib graph ip4-vxlan-bypass}
 *            Name                      Next                    Previous
 * ip4-vxlan-bypass                error-drop [0]
 *                                vxlan4-input [1]
 *                                 ip4-lookup [2]      
 * @cliexend
 *
 * Example of how to enable ip4-vxlan-bypass on an interface:
 * @cliexcmd{set interface ip vxlan-bypass GigabitEthernet2/0/0}
 *
 * Example of graph node after ip4-vxlan-bypass is enabled:
 * @cliexstart{show vlib graph ip4-vxlan-bypass}
 *            Name                      Next                    Previous         
 * ip4-vxlan-bypass                error-drop [0]               ip4-input        
 *                                vxlan4-input [1]        ip4-input-no-checksum  
 *                                 ip4-lookup [2]      
 * @cliexend
 *
 * Example of how to display the feature enabed on an interface:
 * @cliexstart{show ip interface features GigabitEthernet2/0/0}
 * IP feature paths configured on GigabitEthernet2/0/0...
 * ...
 * ipv4 unicast:
 *   ip4-vxlan-bypass
 *   ip4-lookup
 * ...
 * @cliexend
 *
 * Example of how to disable ip4-vxlan-bypass on an interface:
 * @cliexcmd{set interface ip vxlan-bypass GigabitEthernet2/0/0 del}
 * @endparblock
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (set_interface_ip_vxlan_bypass_command, static) = {
  .path = "set interface ip vxlan-bypass",
  .function = set_ip4_vxlan_bypass,
  .short_help = "set interface ip vxlan-bypass <interface> [del]",
};
/* *INDENT-ON* */

static clib_error_t *
set_ip6_vxlan_bypass (vlib_main_t * vm,
                      unformat_input_t * input,
                      vlib_cli_command_t * cmd)
{
  return set_ip_vxlan_bypass (1, input, cmd);
}

/*?
 * This command adds the 'ip6-vxlan-bypass' graph node for a given interface. 
 * By adding the IPv6 vxlan-bypass graph node to an interface, the node checks
 *  for and validate input vxlan packet and bypass ip6-lookup, ip6-local, 
 * ip6-udp-lookup nodes to speedup vxlan packet forwarding. This node will 
 * cause extra overhead to for non-vxlan packets which is kept at a minimum.
 *
 * @cliexpar
 * @parblock
 * Example of graph node before ip6-vxlan-bypass is enabled:
 * @cliexstart{show vlib graph ip6-vxlan-bypass}
 *            Name                      Next                    Previous
 * ip6-vxlan-bypass                error-drop [0]
 *                                vxlan6-input [1]
 *                                 ip6-lookup [2]      
 * @cliexend
 *
 * Example of how to enable ip6-vxlan-bypass on an interface:
 * @cliexcmd{set interface ip6 vxlan-bypass GigabitEthernet2/0/0}
 *
 * Example of graph node after ip6-vxlan-bypass is enabled:
 * @cliexstart{show vlib graph ip6-vxlan-bypass}
 *            Name                      Next                    Previous         
 * ip6-vxlan-bypass                error-drop [0]               ip6-input        
 *                                vxlan6-input [1]        ip4-input-no-checksum  
 *                                 ip6-lookup [2]      
 * @cliexend
 *
 * Example of how to display the feature enabed on an interface:
 * @cliexstart{show ip interface features GigabitEthernet2/0/0}
 * IP feature paths configured on GigabitEthernet2/0/0...
 * ...
 * ipv6 unicast:
 *   ip6-vxlan-bypass
 *   ip6-lookup
 * ...
 * @cliexend
 *
 * Example of how to disable ip6-vxlan-bypass on an interface:
 * @cliexcmd{set interface ip6 vxlan-bypass GigabitEthernet2/0/0 del}
 * @endparblock
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (set_interface_ip6_vxlan_bypass_command, static) = {
  .path = "set interface ip6 vxlan-bypass",
  .function = set_ip6_vxlan_bypass,
  .short_help = "set interface ip vxlan-bypass <interface> [del]",
};
/* *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->vtep6 = hash_create_mem(0,
        sizeof(ip6_address_t),
        sizeof(uword));
  vxm->mcast_shared = hash_create_mem(0,
        sizeof(ip46_address_t),
        sizeof(mcast_shared_t));

  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);