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2019-06-18fib: fib api updatesNeale Ranns1-5/+4
Enhance the route add/del APIs to take a set of paths rather than just one. Most unicast routing protocols calcualte all the available paths in one run of the algorithm so updating all the paths at once is beneficial for the client. two knobs control the behaviour: is_multipath - if set the the set of paths passed will be added to those that already exist, otherwise the set will replace them. is_add - add or remove the set is_add=0, is_multipath=1 and an empty set, results in deleting the route. It is also considerably faster to add multiple paths at once, than one at a time: vat# ip_add_del_route 1.1.1.1/32 count 100000 multipath via 10.10.10.11 100000 routes in .572240 secs, 174751.80 routes/sec vat# ip_add_del_route 1.1.1.1/32 count 100000 multipath via 10.10.10.12 100000 routes in .528383 secs, 189256.54 routes/sec vat# ip_add_del_route 1.1.1.1/32 count 100000 multipath via 10.10.10.13 100000 routes in .757131 secs, 132077.52 routes/sec vat# ip_add_del_route 1.1.1.1/32 count 100000 multipath via 10.10.10.14 100000 routes in .878317 secs, 113854.12 routes/sec vat# ip_route_add_del 1.1.1.1/32 count 100000 multipath via 10.10.10.11 via 10.10.10.12 via 10.10.10.13 via 10.10.10.14 100000 routes in .900212 secs, 111084.93 routes/sec Change-Id: I416b93f7684745099c1adb0b33edac58c9339c1a Signed-off-by: Neale Ranns <neale.ranns@cisco.com> Signed-off-by: Ole Troan <ot@cisco.com> Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
2019-05-22make test: fix bug due to concurrent commitsKlement Sekera1-4/+4
Change-Id: I912745950fe6e3f1688ef66b430ef86cdddd04cd Signed-off-by: Klement Sekera <ksekera@cisco.com>
2019-05-20reassembly: prevent long chain attackKlement Sekera1-0/+72
limit max # of fragments to 3 per packet by default add API option to configure the limit at runtime Change-Id: Ie4b9507bf5c6095b9a5925972b37fe0032f4f9e8 Signed-off-by: Klement Sekera <ksekera@cisco.com>
2019-05-08VPP-1508: Fix zip() under python3.Paul Vinciguerra1-4/+4
Under py3, zip() returns an iterator. Fix so no longer needed in a list contex. Change-Id: I64b4560d990686cc87fd26d703030f9fb2494f12 Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
2019-04-18GRE: API updateNeale Ranns1-2/+2
Change-Id: I5010cd34123c6498230dedac6ba8dd774a1085f9 Signed-off-by: Neale Ranns <nranns@cisco.com>
2019-04-11Tests: Refactor tearDown show command logging, add lifecycle markers.Paul Vinciguerra1-1/+9
This change adds a consistent interface for adding test-specific show commands to log.txt. It also adds log markers for the execution of setUp[Class], tearDown[Class] in the logs. Change-Id: I7d42e396e594a59e866a7d55dac0af25548e657a Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
2019-04-10Tests Cleanup: Fix missing calls to setUpClass/tearDownClass.Paul Vinciguerra1-0/+16
Continuation/Part 2 of https://gerrit.fd.io/r/#/c/17092/ Change-Id: Id0122d84eaf2c05d29e5be63a594d5e528ee7c9a Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
2019-03-11VPP-1508: Use scapy.compat to manage packet level library differences.Paul Vinciguerra1-4/+8
Change-Id: Icdf6abc9e53d33b26fd1d531c7dda6be0bb9cb55 Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
2019-03-07Tests: Refactor payload_to_info()Paul Vinciguerra1-3/+3
All callers of payload_to_info were required to wrap payload with str(). Refactor to call scapy's payload.load for raw payloads or specify the specific fieldname. Change-Id: I1c80599d4df8dc129dbb8274733afaad406d5bcf Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
2019-03-06Tests: Example duplicate code refactoring.Paul Vinciguerra1-273/+243
Refactor of duplicate methods in test/test_reassembly.py. Change-Id: I46f880da6a0ced2acae1fa33c6892d0148b26139 Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
2019-02-19reassembly: fix buffer usage counterKlement Sekera1-0/+5
Change-Id: I713904f8eb2f724cb08dba494c160c14cc8b24a1 Signed-off-by: Klement Sekera <ksekera@cisco.com>
2019-01-10Enable random reassembly test for ARMjuraj.linkes1-4/+1
The underlying failure has been fixed and now the test can be re-enabled. Change-Id: I75251f6150ef1771dc23ea079799229690cf87d9 Signed-off-by: juraj.linkes <juraj.linkes@pantheon.tech>
2018-12-20Tests: Cleanup @skip decorator.Paul Vinciguerra1-1/+1
The runnning environment is static as of module load time, so only evalute the conditions once at module load time. Track-by: VPP-1518 Change-Id: I73b0d17ae1ff90789e70307f168d43921829aec8 Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
2018-12-20reassembly: replace asserts with error countersKlement Sekera1-2/+3
Change-Id: Iaa39aea990bc04147f6a049215e990a567d30106 Signed-off-by: Klement Sekera <ksekera@cisco.com>
2018-12-16VPP-1523: harden reassemblyKlement Sekera1-2/+42
Change-Id: I00d7b38bd99e81e3921ce08cce50d613f11de36e Signed-off-by: Klement Sekera <ksekera@cisco.com>
2018-12-13reassembly: fix internal buffer count accountingKlement Sekera1-0/+31
Change-Id: I6af2c8552aeafe0abc8b8c3e5af1a05640e95919 Signed-off-by: Klement Sekera <ksekera@cisco.com>
2018-12-13VPP-1522: harden reassembly codeKlement Sekera1-3/+28
Change-Id: Ib5a20bff7d8a340ecf50bcd4a023d6bf36382ba3 Signed-off-by: Klement Sekera <ksekera@cisco.com>
2018-12-06Skip failing ARM testcases for CIjuraj.linkes1-1/+4
There are a few tests that fail on ARM and thus we can't enable testing in CI. Skip the failing tests until they're fixed so that we catch new failures in CI (when we enable testing for the remaining tests). Change-Id: Ie896ef5c449ef965029633e38d317a8d5ac26352 Signed-off-by: juraj.linkes <juraj.linkes@pantheon.tech>
2018-11-27VPP-1508 python3 tests: use six.iteritemsPaul Vinciguerra1-5/+7
This replaces dictionary.iteritems() on Python 2 and dictionary.items() on Python 3. Change-Id: I58a3ded7d284c59e28d484b0c285aac435bfc229 Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
2018-10-04Support reassembly for fragments coming to ip4-local nodeJuraj Sloboda1-1/+118
Change-Id: I3aa4708c1c3cdda344f282d56b617677080eaaa1 Signed-off-by: Juraj Sloboda <jsloboda@cisco.com>
2018-09-11GBP Endpoint UpdatesNeale Ranns1-1/+2
- common types on the API - endpoints keyed in various ways for DP lookup - conparison functions for VPP IP address types Change-Id: If7ec0bbc5cea71fd0983fe78987d147ec1bd7ec8 Signed-off-by: Neale Ranns <neale.ranns@cisco.com>
2018-04-03reassembly: bug fixesKlement Sekera1-2/+1
This change fixes a bug which would corrupt features infra by making feature infra resistant to double-removal. It also fixes 'out of memory' issue by properly initializing the bihash tables. Change-Id: I78ac03139234a9a0e0b48e7bdfac1c38a0069e82 Signed-off-by: Klement Sekera <ksekera@cisco.com>
2018-03-21reassembly: feature/concurrencyKlement Sekera1-0/+972
This change makes ip reassembly an interface feature, while adding concurrency support. Due to this, punt is no longer needed to test reassembly. Change-Id: I467669514ec33283ce935be0f1dd08f07684f0c7 Signed-off-by: Klement Sekera <ksekera@cisco.com>
2018-03-07test: disable reassembly tests and system modification scriptDamjan Marion1-966/+0
One of basic requirements from day one for maek test is that it should run unpriviledged, so modifying system paremeters is unacceptable. Disabling script and reassembly tests as they need to be done in different way. Change-Id: I063c73eb82f2ebd7499e8adb1574a9fd2475fb5b Signed-off-by: Damjan Marion <damarion@cisco.com>
2018-02-01IPv4/6 reassemblyKlement Sekera1-0/+966
Change-Id: Ic5dcadd13c88b8a5e7896dab82404509c081614a Signed-off-by: Klement Sekera <ksekera@cisco.com>
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/*
 * ethernet/arp.c: IP v4 ARP node
 *
 * Copyright (c) 2010 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/ip/ip.h>
#include <vnet/ip/ip6.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/ethernet/arp.h>
#include <vnet/l2/l2_input.h>
#include <vppinfra/mhash.h>
#include <vnet/fib/ip4_fib.h>
#include <vnet/fib/fib_entry_src.h>
#include <vnet/adj/adj_nbr.h>
#include <vnet/adj/adj_mcast.h>
#include <vnet/mpls/mpls.h>
#include <vnet/l2/feat_bitmap.h>

/**
 * @file
 * @brief IPv4 ARP.
 *
 * This file contains code to manage the IPv4 ARP tables (IP Address
 * to MAC Address lookup).
 */


void vl_api_rpc_call_main_thread (void *fp, u8 * data, u32 data_length);

/**
 * @brief Per-interface ARP configuration and state
 */
typedef struct ethernet_arp_interface_t_
{
  /**
   * Hash table of ARP entries.
   * Since this hash table is per-interface, the key is only the IPv4 address.
   */
  uword *arp_entries;
} ethernet_arp_interface_t;

typedef struct
{
  ip4_address_t lo_addr;
  ip4_address_t hi_addr;
  u32 fib_index;
} ethernet_proxy_arp_t;

typedef struct
{
  u32 next_index;
  uword node_index;
  uword type_opaque;
  uword data;
  /* Used for arp event notification only */
  void *data_callback;
  u32 pid;
} pending_resolution_t;

typedef struct
{
  /* Hash tables mapping name to opcode. */
  uword *opcode_by_name;

  /* lite beer "glean" adjacency handling */
  uword *pending_resolutions_by_address;
  pending_resolution_t *pending_resolutions;

  /* Mac address change notification */
  uword *mac_changes_by_address;
  pending_resolution_t *mac_changes;

  ethernet_arp_ip4_entry_t *ip4_entry_pool;

  /* ARP attack mitigation */
  u32 arp_delete_rotor;
  u32 limit_arp_cache_size;

  /** Per interface state */
  ethernet_arp_interface_t *ethernet_arp_by_sw_if_index;

  /* Proxy arp vector */
  ethernet_proxy_arp_t *proxy_arps;

  uword wc_ip4_arp_publisher_node;
  uword wc_ip4_arp_publisher_et;
} ethernet_arp_main_t;

static ethernet_arp_main_t ethernet_arp_main;

typedef struct
{
  u32 sw_if_index;
  ethernet_arp_ip4_over_ethernet_address_t a;
  int is_static;
  int is_no_fib_entry;
  int flags;
#define ETHERNET_ARP_ARGS_REMOVE (1<<0)
#define ETHERNET_ARP_ARGS_FLUSH  (1<<1)
#define ETHERNET_ARP_ARGS_POPULATE  (1<<2)
#define ETHERNET_ARP_ARGS_WC_PUB  (1<<3)
} vnet_arp_set_ip4_over_ethernet_rpc_args_t;

static const u8 vrrp_prefix[] = { 0x00, 0x00, 0x5E, 0x00, 0x01 };

/* Node index for send_garp_na_process */
u32 send_garp_na_process_node_index;

static void
set_ip4_over_ethernet_rpc_callback (vnet_arp_set_ip4_over_ethernet_rpc_args_t
				    * a);

static u8 *
format_ethernet_arp_hardware_type (u8 * s, va_list * va)
{
  ethernet_arp_hardware_type_t h = va_arg (*va, ethernet_arp_hardware_type_t);
  char *t = 0;
  switch (h)
    {
#define _(n,f) case n: t = #f; break;
      foreach_ethernet_arp_hardware_type;
#undef _

    default:
      return format (s, "unknown 0x%x", h);
    }

  return format (s, "%s", t);
}

static u8 *
format_ethernet_arp_opcode (u8 * s, va_list * va)
{
  ethernet_arp_opcode_t o = va_arg (*va, ethernet_arp_opcode_t);
  char *t = 0;
  switch (o)
    {
#define _(f) case ETHERNET_ARP_OPCODE_##f: t = #f; break;
      foreach_ethernet_arp_opcode;
#undef _

    default:
      return format (s, "unknown 0x%x", o);
    }

  return format (s, "%s", t);
}

static uword
unformat_ethernet_arp_opcode_host_byte_order (unformat_input_t * input,
					      va_list * args)
{
  int *result = va_arg (*args, int *);
  ethernet_arp_main_t *am = &ethernet_arp_main;
  int x, i;

  /* Numeric opcode. */
  if (unformat (input, "0x%x", &x) || unformat (input, "%d", &x))
    {
      if (x >= (1 << 16))
	return 0;
      *result = x;
      return 1;
    }

  /* Named type. */
  if (unformat_user (input, unformat_vlib_number_by_name,
		     am->opcode_by_name, &i))
    {
      *result = i;
      return 1;
    }

  return 0;
}

static uword
unformat_ethernet_arp_opcode_net_byte_order (unformat_input_t * input,
					     va_list * args)
{
  int *result = va_arg (*args, int *);
  if (!unformat_user
      (input, unformat_ethernet_arp_opcode_host_byte_order, result))
    return 0;

  *result = clib_host_to_net_u16 ((u16) * result);
  return 1;
}

static u8 *
format_ethernet_arp_header (u8 * s, va_list * va)
{
  ethernet_arp_header_t *a = va_arg (*va, ethernet_arp_header_t *);
  u32 max_header_bytes = va_arg (*va, u32);
  u32 indent;
  u16 l2_type, l3_type;

  if (max_header_bytes != 0 && sizeof (a[0]) > max_header_bytes)
    return format (s, "ARP header truncated");

  l2_type = clib_net_to_host_u16 (a->l2_type);
  l3_type = clib_net_to_host_u16 (a->l3_type);

  indent = format_get_indent (s);

  s = format (s, "%U, type %U/%U, address size %d/%d",
	      format_ethernet_arp_opcode, clib_net_to_host_u16 (a->opcode),
	      format_ethernet_arp_hardware_type, l2_type,
	      format_ethernet_type, l3_type,
	      a->n_l2_address_bytes, a->n_l3_address_bytes);

  if (l2_type == ETHERNET_ARP_HARDWARE_TYPE_ethernet
      && l3_type == ETHERNET_TYPE_IP4)
    {
      s = format (s, "\n%U%U/%U -> %U/%U",
		  format_white_space, indent,
		  format_ethernet_address, a->ip4_over_ethernet[0].ethernet,
		  format_ip4_address, &a->ip4_over_ethernet[0].ip4,
		  format_ethernet_address, a->ip4_over_ethernet[1].ethernet,
		  format_ip4_address, &a->ip4_over_ethernet[1].ip4);
    }
  else
    {
      uword n2 = a->n_l2_address_bytes;
      uword n3 = a->n_l3_address_bytes;
      s = format (s, "\n%U%U/%U -> %U/%U",
		  format_white_space, indent,
		  format_hex_bytes, a->data + 0 * n2 + 0 * n3, n2,
		  format_hex_bytes, a->data + 1 * n2 + 0 * n3, n3,
		  format_hex_bytes, a->data + 1 * n2 + 1 * n3, n2,
		  format_hex_bytes, a->data + 2 * n2 + 1 * n3, n3);
    }

  return s;
}

u8 *
format_ethernet_arp_ip4_entry (u8 * s, va_list * va)
{
  vnet_main_t *vnm = va_arg (*va, vnet_main_t *);
  ethernet_arp_ip4_entry_t *e = va_arg (*va, ethernet_arp_ip4_entry_t *);
  vnet_sw_interface_t *si;
  u8 *flags = 0;

  if (!e)
    return format (s, "%=12s%=16s%=6s%=20s%=24s", "Time", "IP4",
		   "Flags", "Ethernet", "Interface");

  si = vnet_get_sw_interface (vnm, e->sw_if_index);

  if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC)
    flags = format (flags, "S");

  if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC)
    flags = format (flags, "D");

  if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_NO_FIB_ENTRY)
    flags = format (flags, "N");

  s = format (s, "%=12U%=16U%=6s%=20U%U",
	      format_vlib_time, vnm->vlib_main, e->time_last_updated,
	      format_ip4_address, &e->ip4_address,
	      flags ? (char *) flags : "",
	      format_ethernet_address, e->ethernet_address,
	      format_vnet_sw_interface_name, vnm, si);

  vec_free (flags);
  return s;
}

typedef struct
{
  u8 packet_data[64];
} ethernet_arp_input_trace_t;

static u8 *
format_ethernet_arp_input_trace (u8 * s, va_list * va)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
  ethernet_arp_input_trace_t *t = va_arg (*va, ethernet_arp_input_trace_t *);

  s = format (s, "%U",
	      format_ethernet_arp_header,
	      t->packet_data, sizeof (t->packet_data));

  return s;
}

static u8 *
format_arp_term_input_trace (u8 * s, va_list * va)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
  ethernet_arp_input_trace_t *t = va_arg (*va, ethernet_arp_input_trace_t *);

  /* arp-term trace data saved is either arp or ip6/icmp6 packet:
     - for arp, the 1st 16-bit field is hw type of value of 0x0001.
     - for ip6, the first nibble has value of 6. */
  s = format (s, "%U", t->packet_data[0] == 0 ?
	      format_ethernet_arp_header : format_ip6_header,
	      t->packet_data, sizeof (t->packet_data));

  return s;
}

static void
arp_nbr_probe (ip_adjacency_t * adj)
{
  vnet_main_t *vnm = vnet_get_main ();
  ip4_main_t *im = &ip4_main;
  ip_interface_address_t *ia;
  ethernet_arp_header_t *h;
  vnet_hw_interface_t *hi;
  vnet_sw_interface_t *si;
  ip4_address_t *src;
  vlib_buffer_t *b;
  vlib_main_t *vm;
  u32 bi = 0;

  vm = vlib_get_main ();

  si = vnet_get_sw_interface (vnm, adj->rewrite_header.sw_if_index);

  if (!(si->flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP))
    {
      return;
    }

  src =
    ip4_interface_address_matching_destination (im,
						&adj->sub_type.nbr.next_hop.
						ip4,
						adj->rewrite_header.
						sw_if_index, &ia);
  if (!src)
    {
      return;
    }

  h =
    vlib_packet_template_get_packet (vm, &im->ip4_arp_request_packet_template,
				     &bi);
  if (!h)
    return;

  hi = vnet_get_sup_hw_interface (vnm, adj->rewrite_header.sw_if_index);

  clib_memcpy_fast (h->ip4_over_ethernet[0].ethernet,
		    hi->hw_address,
		    sizeof (h->ip4_over_ethernet[0].ethernet));

  h->ip4_over_ethernet[0].ip4 = src[0];
  h->ip4_over_ethernet[1].ip4 = adj->sub_type.nbr.next_hop.ip4;

  b = vlib_get_buffer (vm, bi);
  vnet_buffer (b)->sw_if_index[VLIB_RX] =
    vnet_buffer (b)->sw_if_index[VLIB_TX] = adj->rewrite_header.sw_if_index;

  /* Add encapsulation string for software interface (e.g. ethernet header). */
  vnet_rewrite_one_header (adj[0], h, sizeof (ethernet_header_t));
  vlib_buffer_advance (b, -adj->rewrite_header.data_bytes);

  {
    vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
    u32 *to_next = vlib_frame_vector_args (f);
    to_next[0] = bi;
    f->n_vectors = 1;
    vlib_put_frame_to_node (vm, hi->output_node_index, f);
  }
}

static void
arp_mk_complete (adj_index_t ai, ethernet_arp_ip4_entry_t * e)
{
  adj_nbr_update_rewrite
    (ai, ADJ_NBR_REWRITE_FLAG_COMPLETE,
     ethernet_build_rewrite (vnet_get_main (),
			     e->sw_if_index,
			     adj_get_link_type (ai), e->ethernet_address));
}

static void
arp_mk_incomplete (adj_index_t ai)
{
  ip_adjacency_t *adj = adj_get (ai);

  adj_nbr_update_rewrite
    (ai,
     ADJ_NBR_REWRITE_FLAG_INCOMPLETE,
     ethernet_build_rewrite (vnet_get_main (),
			     adj->rewrite_header.sw_if_index,
			     VNET_LINK_ARP,
			     VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST));
}

static ethernet_arp_ip4_entry_t *
arp_entry_find (ethernet_arp_interface_t * eai, const ip4_address_t * addr)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e = NULL;
  uword *p;

  if (NULL != eai->arp_entries)
    {
      p = hash_get (eai->arp_entries, addr->as_u32);
      if (!p)
	return (NULL);

      e = pool_elt_at_index (am->ip4_entry_pool, p[0]);
    }

  return (e);
}

static adj_walk_rc_t
arp_mk_complete_walk (adj_index_t ai, void *ctx)
{
  ethernet_arp_ip4_entry_t *e = ctx;

  arp_mk_complete (ai, e);

  return (ADJ_WALK_RC_CONTINUE);
}

static adj_walk_rc_t
arp_mk_incomplete_walk (adj_index_t ai, void *ctx)
{
  arp_mk_incomplete (ai);

  return (ADJ_WALK_RC_CONTINUE);
}

void
arp_update_adjacency (vnet_main_t * vnm, u32 sw_if_index, u32 ai)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_interface_t *arp_int;
  ethernet_arp_ip4_entry_t *e;
  ip_adjacency_t *adj;

  adj = adj_get (ai);

  vec_validate (am->ethernet_arp_by_sw_if_index, sw_if_index);
  arp_int = &am->ethernet_arp_by_sw_if_index[sw_if_index];
  e = arp_entry_find (arp_int, &adj->sub_type.nbr.next_hop.ip4);

  switch (adj->lookup_next_index)
    {
    case IP_LOOKUP_NEXT_GLEAN:
      adj_glean_update_rewrite (ai);
      break;
    case IP_LOOKUP_NEXT_ARP:
      if (NULL != e)
	{
	  adj_nbr_walk_nh4 (sw_if_index,
			    &e->ip4_address, arp_mk_complete_walk, e);
	}
      else
	{
	  /*
	   * no matching ARP entry.
	   * construct the rewrite required to for an ARP packet, and stick
	   * that in the adj's pipe to smoke.
	   */
	  adj_nbr_update_rewrite
	    (ai,
	     ADJ_NBR_REWRITE_FLAG_INCOMPLETE,
	     ethernet_build_rewrite
	     (vnm,
	      sw_if_index,
	      VNET_LINK_ARP,
	      VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST));

	  /*
	   * since the FIB has added this adj for a route, it makes sense it
	   * may want to forward traffic sometime soon. Let's send a
	   * speculative ARP. just one. If we were to do periodically that
	   * wouldn't be bad either, but that's more code than i'm prepared to
	   * write at this time for relatively little reward.
	   */
	  arp_nbr_probe (adj);
	}
      break;
    case IP_LOOKUP_NEXT_BCAST:
      adj_nbr_update_rewrite (ai,
			      ADJ_NBR_REWRITE_FLAG_COMPLETE,
			      ethernet_build_rewrite
			      (vnm,
			       sw_if_index,
			       VNET_LINK_IP4,
			       VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST));
      break;
    case IP_LOOKUP_NEXT_MCAST:
      {
	/*
	 * Construct a partial rewrite from the known ethernet mcast dest MAC
	 */
	u8 *rewrite;
	u8 offset;

	rewrite = ethernet_build_rewrite (vnm,
					  sw_if_index,
					  adj->ia_link,
					  ethernet_ip4_mcast_dst_addr ());
	offset = vec_len (rewrite) - 2;

	/*
	 * Complete the remaining fields of the adj's rewrite to direct the
	 * complete of the rewrite at switch time by copying in the IP
	 * dst address's bytes.
	 * Ofset is 2 bytes into the MAC desintation address.
	 */
	adj_mcast_update_rewrite (ai, rewrite, offset);

	break;
      }
    case IP_LOOKUP_NEXT_DROP:
    case IP_LOOKUP_NEXT_PUNT:
    case IP_LOOKUP_NEXT_LOCAL:
    case IP_LOOKUP_NEXT_REWRITE:
    case IP_LOOKUP_NEXT_MCAST_MIDCHAIN:
    case IP_LOOKUP_NEXT_MIDCHAIN:
    case IP_LOOKUP_NEXT_ICMP_ERROR:
    case IP_LOOKUP_N_NEXT:
      ASSERT (0);
      break;
    }
}

static void
arp_adj_fib_add (ethernet_arp_ip4_entry_t * e, u32 fib_index)
{
  fib_prefix_t pfx = {
    .fp_len = 32,
    .fp_proto = FIB_PROTOCOL_IP4,
    .fp_addr.ip4 = e->ip4_address,
  };

  e->fib_entry_index =
    fib_table_entry_path_add (fib_index, &pfx, FIB_SOURCE_ADJ,
			      FIB_ENTRY_FLAG_ATTACHED,
			      DPO_PROTO_IP4, &pfx.fp_addr,
			      e->sw_if_index, ~0, 1, NULL,
			      FIB_ROUTE_PATH_FLAG_NONE);
  fib_table_lock (fib_index, FIB_PROTOCOL_IP4, FIB_SOURCE_ADJ);
}

static void
arp_adj_fib_remove (ethernet_arp_ip4_entry_t * e, u32 fib_index)
{
  if (FIB_NODE_INDEX_INVALID != e->fib_entry_index)
    {
      fib_prefix_t pfx = {
	.fp_len = 32,
	.fp_proto = FIB_PROTOCOL_IP4,
	.fp_addr.ip4 = e->ip4_address,
      };
      u32 fib_index;

      fib_index = ip4_fib_table_get_index_for_sw_if_index (e->sw_if_index);

      fib_table_entry_path_remove (fib_index, &pfx,
				   FIB_SOURCE_ADJ,
				   DPO_PROTO_IP4,
				   &pfx.fp_addr,
				   e->sw_if_index, ~0, 1,
				   FIB_ROUTE_PATH_FLAG_NONE);
      fib_table_unlock (fib_index, FIB_PROTOCOL_IP4, FIB_SOURCE_ADJ);
    }
}

static ethernet_arp_ip4_entry_t *
force_reuse_arp_entry (void)
{
  ethernet_arp_ip4_entry_t *e;
  ethernet_arp_main_t *am = &ethernet_arp_main;
  u32 count = 0;
  u32 index = pool_next_index (am->ip4_entry_pool, am->arp_delete_rotor);
  if (index == ~0)		/* Try again from elt 0 */
    index = pool_next_index (am->ip4_entry_pool, index);

  /* Find a non-static random entry to free up for reuse */
  do
    {
      if ((count++ == 100) || (index == ~0))
	return NULL;		/* give up after 100 entries */
      e = pool_elt_at_index (am->ip4_entry_pool, index);
      am->arp_delete_rotor = index;
      index = pool_next_index (am->ip4_entry_pool, index);
    }
  while (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC);

  /* Remove ARP entry from its interface and update fib */
  hash_unset
    (am->ethernet_arp_by_sw_if_index[e->sw_if_index].arp_entries,
     e->ip4_address.as_u32);
  arp_adj_fib_remove
    (e, ip4_fib_table_get_index_for_sw_if_index (e->sw_if_index));
  adj_nbr_walk_nh4 (e->sw_if_index,
		    &e->ip4_address, arp_mk_incomplete_walk, e);
  return e;
}

static int
vnet_arp_set_ip4_over_ethernet_internal (vnet_main_t * vnm,
					 vnet_arp_set_ip4_over_ethernet_rpc_args_t
					 * args)
{
  ethernet_arp_ip4_entry_t *e = 0;
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_over_ethernet_address_t *a = &args->a;
  vlib_main_t *vm = vlib_get_main ();
  int make_new_arp_cache_entry = 1;
  uword *p;
  pending_resolution_t *pr, *mc;
  ethernet_arp_interface_t *arp_int;
  int is_static = args->is_static;
  u32 sw_if_index = args->sw_if_index;
  int is_no_fib_entry = args->is_no_fib_entry;

  vec_validate (am->ethernet_arp_by_sw_if_index, sw_if_index);

  arp_int = &am->ethernet_arp_by_sw_if_index[sw_if_index];

  if (NULL != arp_int->arp_entries)
    {
      p = hash_get (arp_int->arp_entries, a->ip4.as_u32);
      if (p)
	{
	  e = pool_elt_at_index (am->ip4_entry_pool, p[0]);

	  /* Refuse to over-write static arp. */
	  if (!is_static && (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC))
	    {
	      /* if MAC address match, still check to send event */
	      if (0 == memcmp (e->ethernet_address,
			       a->ethernet, sizeof (e->ethernet_address)))
		goto check_customers;
	      return -2;
	    }
	  make_new_arp_cache_entry = 0;
	}
    }

  if (make_new_arp_cache_entry)
    {
      if (am->limit_arp_cache_size &&
	  pool_elts (am->ip4_entry_pool) >= am->limit_arp_cache_size)
	{
	  e = force_reuse_arp_entry ();
	  if (NULL == e)
	    return -2;
	}
      else
	pool_get (am->ip4_entry_pool, e);

      if (NULL == arp_int->arp_entries)
	arp_int->arp_entries = hash_create (0, sizeof (u32));

      hash_set (arp_int->arp_entries, a->ip4.as_u32, e - am->ip4_entry_pool);

      e->sw_if_index = sw_if_index;
      e->ip4_address = a->ip4;
      e->fib_entry_index = FIB_NODE_INDEX_INVALID;
      clib_memcpy_fast (e->ethernet_address,
			a->ethernet, sizeof (e->ethernet_address));

      if (!is_no_fib_entry)
	{
	  arp_adj_fib_add (e,
			   ip4_fib_table_get_index_for_sw_if_index
			   (e->sw_if_index));
	}
      else
	{
	  e->flags |= ETHERNET_ARP_IP4_ENTRY_FLAG_NO_FIB_ENTRY;
	}
    }
  else
    {
      /*
       * prevent a DoS attack from the data-plane that
       * spams us with no-op updates to the MAC address
       */
      if (0 == memcmp (e->ethernet_address,
		       a->ethernet, sizeof (e->ethernet_address)))
	{
	  e->time_last_updated = vlib_time_now (vm);
	  goto check_customers;
	}

      /* Update ethernet address. */
      clib_memcpy_fast (e->ethernet_address, a->ethernet,
			sizeof (e->ethernet_address));
    }

  /* Update time stamp and flags. */
  e->time_last_updated = vlib_time_now (vm);
  if (is_static)
    {
      e->flags &= ~ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC;
      e->flags |= ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC;
    }
  else
    {
      e->flags &= ~ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC;
      e->flags |= ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC;
    }

  adj_nbr_walk_nh4 (sw_if_index, &e->ip4_address, arp_mk_complete_walk, e);

check_customers:
  /* Customer(s) waiting for this address to be resolved? */
  p = hash_get (am->pending_resolutions_by_address, a->ip4.as_u32);
  if (p)
    {
      u32 next_index;
      next_index = p[0];

      while (next_index != (u32) ~ 0)
	{
	  pr = pool_elt_at_index (am->pending_resolutions, next_index);
	  vlib_process_signal_event (vm, pr->node_index,
				     pr->type_opaque, pr->data);
	  next_index = pr->next_index;
	  pool_put (am->pending_resolutions, pr);
	}

      hash_unset (am->pending_resolutions_by_address, a->ip4.as_u32);
    }

  /* Customer(s) requesting ARP event for this address? */
  p = hash_get (am->mac_changes_by_address, a->ip4.as_u32);
  if (p)
    {
      u32 next_index;
      next_index = p[0];

      while (next_index != (u32) ~ 0)
	{
	  int (*fp) (u32, u8 *, u32, u32);
	  int rv = 1;
	  mc = pool_elt_at_index (am->mac_changes, next_index);
	  fp = mc->data_callback;

	  /* Call the user's data callback, return 1 to suppress dup events */
	  if (fp)
	    rv = (*fp) (mc->data, a->ethernet, sw_if_index, 0);

	  /*
	   * Signal the resolver process, as long as the user
	   * says they want to be notified
	   */
	  if (rv == 0)
	    vlib_process_signal_event (vm, mc->node_index,
				       mc->type_opaque, mc->data);
	  next_index = mc->next_index;
	}
    }

  return 0;
}

void
vnet_register_ip4_arp_resolution_event (vnet_main_t * vnm,
					void *address_arg,
					uword node_index,
					uword type_opaque, uword data)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ip4_address_t *address = address_arg;
  uword *p;
  pending_resolution_t *pr;

  pool_get (am->pending_resolutions, pr);

  pr->next_index = ~0;
  pr->node_index = node_index;
  pr->type_opaque = type_opaque;
  pr->data = data;
  pr->data_callback = 0;

  p = hash_get (am->pending_resolutions_by_address, address->as_u32);
  if (p)
    {
      /* Insert new resolution at the head of the list */
      pr->next_index = p[0];
      hash_unset (am->pending_resolutions_by_address, address->as_u32);
    }

  hash_set (am->pending_resolutions_by_address, address->as_u32,
	    pr - am->pending_resolutions);
}

int
vnet_add_del_ip4_arp_change_event (vnet_main_t * vnm,
				   void *data_callback,
				   u32 pid,
				   void *address_arg,
				   uword node_index,
				   uword type_opaque, uword data, int is_add)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ip4_address_t *address = address_arg;

  /* Try to find an existing entry */
  u32 *first = (u32 *) hash_get (am->mac_changes_by_address, address->as_u32);
  u32 *p = first;
  pending_resolution_t *mc;
  while (p && *p != ~0)
    {
      mc = pool_elt_at_index (am->mac_changes, *p);
      if (mc->node_index == node_index && mc->type_opaque == type_opaque
	  && mc->pid == pid)
	break;
      p = &mc->next_index;
    }

  int found = p && *p != ~0;
  if (is_add)
    {
      if (found)
	return VNET_API_ERROR_ENTRY_ALREADY_EXISTS;

      pool_get (am->mac_changes, mc);
      *mc = (pending_resolution_t)
      {
      .next_index = ~0,.node_index = node_index,.type_opaque =
	  type_opaque,.data = data,.data_callback = data_callback,.pid =
	  pid,};

      /* Insert new resolution at the end of the list */
      u32 new_idx = mc - am->mac_changes;
      if (p)
	p[0] = new_idx;
      else
	hash_set (am->mac_changes_by_address, address->as_u32, new_idx);
    }
  else
    {
      if (!found)
	return VNET_API_ERROR_NO_SUCH_ENTRY;

      /* Clients may need to clean up pool entries, too */
      void (*fp) (u32, u8 *) = data_callback;
      if (fp)
	(*fp) (mc->data, 0 /* no new mac addrs */ );

      /* Remove the entry from the list and delete the entry */
      *p = mc->next_index;
      pool_put (am->mac_changes, mc);

      /* Remove from hash if we deleted the last entry */
      if (*p == ~0 && p == first)
	hash_unset (am->mac_changes_by_address, address->as_u32);
    }
  return 0;
}

/* Either we drop the packet or we send a reply to the sender. */
typedef enum
{
  ARP_INPUT_NEXT_DROP,
  ARP_INPUT_NEXT_REPLY_TX,
  ARP_INPUT_N_NEXT,
} arp_input_next_t;

#define foreach_ethernet_arp_error					\
  _ (replies_sent, "ARP replies sent")					\
  _ (l2_type_not_ethernet, "L2 type not ethernet")			\
  _ (l3_type_not_ip4, "L3 type not IP4")				\
  _ (l3_src_address_not_local, "IP4 source address not local to subnet") \
  _ (l3_dst_address_not_local, "IP4 destination address not local to subnet") \
  _ (l3_dst_address_unset, "IP4 destination address is unset")          \
  _ (l3_src_address_is_local, "IP4 source address matches local interface") \
  _ (l3_src_address_learned, "ARP request IP4 source address learned")  \
  _ (replies_received, "ARP replies received")				\
  _ (opcode_not_request, "ARP opcode not request")                      \
  _ (proxy_arp_replies_sent, "Proxy ARP replies sent")			\
  _ (l2_address_mismatch, "ARP hw addr does not match L2 frame src addr") \
  _ (gratuitous_arp, "ARP probe or announcement dropped") \
  _ (interface_no_table, "Interface is not mapped to an IP table") \
  _ (interface_not_ip_enabled, "Interface is not IP enabled") \

typedef enum
{
#define _(sym,string) ETHERNET_ARP_ERROR_##sym,
  foreach_ethernet_arp_error
#undef _
    ETHERNET_ARP_N_ERROR,
} ethernet_arp_input_error_t;

static int
arp_unnumbered (vlib_buffer_t * p0,
		u32 input_sw_if_index, u32 conn_sw_if_index)
{
  vnet_main_t *vnm = vnet_get_main ();
  vnet_interface_main_t *vim = &vnm->interface_main;
  vnet_sw_interface_t *si;

  /* verify that the input interface is unnumbered to the connected.
   * the connected interface is the interface on which the subnet is
   * configured */
  si = &vim->sw_interfaces[input_sw_if_index];

  if (!(si->flags & VNET_SW_INTERFACE_FLAG_UNNUMBERED &&
	(si->unnumbered_sw_if_index == conn_sw_if_index)))
    {
      /* the input interface is not unnumbered to the interface on which
       * the sub-net is configured that covers the ARP request.
       * So this is not the case for unnumbered.. */
      return 0;
    }

  return !0;
}

static u32
arp_learn (vnet_main_t * vnm,
	   ethernet_arp_main_t * am, u32 sw_if_index,
	   const ethernet_arp_ip4_over_ethernet_address_t * addr)
{
  vnet_arp_set_ip4_over_ethernet (vnm, sw_if_index, addr, 0, 0);
  return (ETHERNET_ARP_ERROR_l3_src_address_learned);
}

static uword
arp_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  vnet_main_t *vnm = vnet_get_main ();
  ip4_main_t *im4 = &ip4_main;
  u32 n_left_from, next_index, *from, *to_next;
  u32 n_replies_sent = 0, n_proxy_arp_replies_sent = 0;

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    vlib_trace_frame_buffers_only (vm, node, from, frame->n_vectors,
				   /* stride */ 1,
				   sizeof (ethernet_arp_input_trace_t));

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  vlib_buffer_t *p0;
	  vnet_hw_interface_t *hw_if0;
	  ethernet_arp_header_t *arp0;
	  ethernet_header_t *eth_rx, *eth_tx;
	  const ip4_address_t *if_addr0;
	  ip4_address_t proxy_src;
	  u32 pi0, error0, next0, sw_if_index0, conn_sw_if_index0, fib_index0;
	  u8 is_request0, dst_is_local0, is_unnum0, is_vrrp_reply0;
	  ethernet_proxy_arp_t *pa;
	  fib_node_index_t dst_fei, src_fei;
	  const fib_prefix_t *pfx0;
	  fib_entry_flag_t src_flags, dst_flags;
	  u8 *rewrite0, rewrite0_len;

	  pi0 = from[0];
	  to_next[0] = pi0;
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;
	  pa = 0;

	  p0 = vlib_get_buffer (vm, pi0);
	  arp0 = vlib_buffer_get_current (p0);
	  /* Fill in ethernet header. */
	  eth_rx = ethernet_buffer_get_header (p0);

	  is_request0 = arp0->opcode
	    == clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_request);

	  error0 = ETHERNET_ARP_ERROR_replies_sent;

	  error0 =
	    (arp0->l2_type !=
	     clib_net_to_host_u16 (ETHERNET_ARP_HARDWARE_TYPE_ethernet) ?
	     ETHERNET_ARP_ERROR_l2_type_not_ethernet : error0);
	  error0 =
	    (arp0->l3_type !=
	     clib_net_to_host_u16 (ETHERNET_TYPE_IP4) ?
	     ETHERNET_ARP_ERROR_l3_type_not_ip4 : error0);
	  error0 =
	    (0 == arp0->ip4_over_ethernet[0].ip4.as_u32 ?
	     ETHERNET_ARP_ERROR_l3_dst_address_unset : error0);

	  sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX];

	  /* not playing the ARP game if the interface is not IPv4 enabled */
	  error0 =
	    (im4->ip_enabled_by_sw_if_index[sw_if_index0] == 0 ?
	     ETHERNET_ARP_ERROR_interface_not_ip_enabled : error0);

	  if (error0)
	    goto drop2;

	  /* Check that IP address is local and matches incoming interface. */
	  fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
	  if (~0 == fib_index0)
	    {
	      error0 = ETHERNET_ARP_ERROR_interface_no_table;
	      goto drop2;

	    }
	  dst_fei = ip4_fib_table_lookup (ip4_fib_get (fib_index0),
					  &arp0->ip4_over_ethernet[1].ip4,
					  32);
	  dst_flags = fib_entry_get_flags (dst_fei);

	  conn_sw_if_index0 = fib_entry_get_resolving_interface (dst_fei);

	  /* Honor unnumbered interface, if any */
	  is_unnum0 = sw_if_index0 != conn_sw_if_index0;

	  {
	    /*
	     * we're looking for FIB entries that indicate the source
	     * is attached. There may be more specific non-attached
	     * routes that match the source, but these do not influence
	     * whether we respond to an ARP request, i.e. they do not
	     * influence whether we are the correct way for the sender
	     * to reach us, they only affect how we reach the sender.
	     */
	    fib_entry_t *src_fib_entry;
	    const fib_prefix_t *pfx;
	    fib_entry_src_t *src;
	    fib_source_t source;
	    int attached;
	    int mask;

	    mask = 32;
	    attached = 0;

	    do
	      {
		src_fei = ip4_fib_table_lookup (ip4_fib_get (fib_index0),
						&arp0->
						ip4_over_ethernet[0].ip4,
						mask);
		src_fib_entry = fib_entry_get (src_fei);

		/*
		 * It's possible that the source that provides the
		 * flags we need, or the flags we must not have,
		 * is not the best source, so check then all.
		 */
                /* *INDENT-OFF* */
                FOR_EACH_SRC_ADDED(src_fib_entry, src, source,
                ({
                  src_flags = fib_entry_get_flags_for_source (src_fei, source);

                  /* Reject requests/replies with our local interface
                     address. */
                  if (FIB_ENTRY_FLAG_LOCAL & src_flags)
                    {
                      error0 = ETHERNET_ARP_ERROR_l3_src_address_is_local;
                      /*
                       * When VPP has an interface whose address is also
                       * applied to a TAP interface on the host, then VPP's
                       * TAP interface will be unnumbered  to the 'real'
                       * interface and do proxy ARP from the host.
                       * The curious aspect of this setup is that ARP requests
                       * from the host will come from the VPP's own address.
                       * So don't drop immediately here, instead go see if this
                       * is a proxy ARP case.
                       */
                      goto drop1;
                    }
                  /* A Source must also be local to subnet of matching
                   * interface address. */
                  if ((FIB_ENTRY_FLAG_ATTACHED & src_flags) ||
                      (FIB_ENTRY_FLAG_CONNECTED & src_flags))
                    {
                      attached = 1;
                      break;
                    }
                  /*
                   * else
                   *  The packet was sent from an address that is not
                   *  connected nor attached i.e. it is not from an
                   *  address that is covered by a link's sub-net,
                   *  nor is it a already learned host resp.
                   */
                }));
                /* *INDENT-ON* */

		/*
		 * shorter mask lookup for the next iteration.
		 */
		pfx = fib_entry_get_prefix (src_fei);
		mask = pfx->fp_len - 1;

		/*
		 * continue until we hit the default route or we find
		 * the attached we are looking for. The most likely
		 * outcome is we find the attached with the first source
		 * on the first lookup.
		 */
	      }
	    while (!attached &&
		   !fib_entry_is_sourced (src_fei, FIB_SOURCE_DEFAULT_ROUTE));

	    if (!attached)
	      {
		/*
		 * the matching route is a not attached, i.e. it was
		 * added as a result of routing, rather than interface/ARP
		 * configuration. If the matching route is not a host route
		 * (i.e. a /32)
		 */
		error0 = ETHERNET_ARP_ERROR_l3_src_address_not_local;
		goto drop2;
	      }
	  }

	  if (fib_entry_is_sourced (dst_fei, FIB_SOURCE_ADJ))
	    {
	      /*
	       * We matched an adj-fib on ths source subnet (a /32 previously
	       * added as a result of ARP). If this request is a gratuitous
	       * ARP, then learn from it.
	       * The check for matching an adj-fib, is to prevent hosts
	       * from spamming us with gratuitous ARPS that might otherwise
	       * blow our ARP cache
	       */
	      if (arp0->ip4_over_ethernet[0].ip4.as_u32 ==
		  arp0->ip4_over_ethernet[1].ip4.as_u32)
		error0 = arp_learn (vnm, am, sw_if_index0,
				    &arp0->ip4_over_ethernet[0]);
	      goto drop2;
	    }
	  else if (!(FIB_ENTRY_FLAG_CONNECTED & dst_flags))
	    {
	      error0 = ETHERNET_ARP_ERROR_l3_dst_address_not_local;
	      goto drop1;
	    }

	  if (sw_if_index0 != fib_entry_get_resolving_interface (src_fei))
	    {
	      /*
	       * The interface the ARP was received on is not the interface
	       * on which the covering prefix is configured. Maybe this is a
	       * case for unnumbered.
	       */
	      is_unnum0 = 1;
	    }

	  dst_is_local0 = (FIB_ENTRY_FLAG_LOCAL & dst_flags);
	  pfx0 = fib_entry_get_prefix (dst_fei);
	  if_addr0 = &pfx0->fp_addr.ip4;

	  is_vrrp_reply0 =
	    ((arp0->opcode ==
	      clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply))
	     &&
	     (!memcmp
	      (arp0->ip4_over_ethernet[0].ethernet, vrrp_prefix,
	       sizeof (vrrp_prefix))));

	  /* Trash ARP packets whose ARP-level source addresses do not
	     match their L2-frame-level source addresses, unless it's
	     a reply from a VRRP virtual router */
	  if (memcmp
	      (eth_rx->src_address, arp0->ip4_over_ethernet[0].ethernet,
	       sizeof (eth_rx->src_address)) && !is_vrrp_reply0)
	    {
	      error0 = ETHERNET_ARP_ERROR_l2_address_mismatch;
	      goto drop2;
	    }

	  /* Learn or update sender's mapping only for replies to addresses
	   * that are local to the subnet */
	  if (arp0->opcode ==
	      clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply))
	    {
	      if (dst_is_local0)
		error0 = arp_learn (vnm, am, sw_if_index0,
				    &arp0->ip4_over_ethernet[0]);
	      else
		/* a reply for a non-local destination could be a GARP.
		 * GARPs for hosts we know were handled above, so this one
		 * we drop */
		error0 = ETHERNET_ARP_ERROR_l3_dst_address_not_local;

	      goto drop1;
	    }
	  else if (arp0->opcode ==
		   clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_request) &&
		   (dst_is_local0 == 0))
	    {
	      goto drop1;
	    }

	send_reply:
	  /* Send a reply.
	     An adjacency to the sender is not always present,
	     so we use the interface to build us a rewrite string
	     which will contain all the necessary tags. */
	  rewrite0 = ethernet_build_rewrite (vnm, sw_if_index0,
					     VNET_LINK_ARP,
					     eth_rx->src_address);
	  rewrite0_len = vec_len (rewrite0);

	  /* Figure out how much to rewind current data from adjacency. */
	  vlib_buffer_advance (p0, -rewrite0_len);
	  eth_tx = vlib_buffer_get_current (p0);

	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
	  hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);

	  /* Send reply back through input interface */
	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
	  next0 = ARP_INPUT_NEXT_REPLY_TX;

	  arp0->opcode = clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply);

	  arp0->ip4_over_ethernet[1] = arp0->ip4_over_ethernet[0];

	  clib_memcpy_fast (arp0->ip4_over_ethernet[0].ethernet,
			    hw_if0->hw_address, 6);
	  clib_mem_unaligned (&arp0->ip4_over_ethernet[0].ip4.data_u32, u32) =
	    if_addr0->data_u32;

	  /* Hardware must be ethernet-like. */
	  ASSERT (vec_len (hw_if0->hw_address) == 6);

	  /* the rx nd tx ethernet headers wil overlap in the case
	   * when we received a tagged VLAN=0 packet, but we are sending
	   * back untagged */
	  clib_memcpy_fast (eth_tx, rewrite0, vec_len (rewrite0));
	  vec_free (rewrite0);

	  if (NULL == pa)
	    {
	      if (is_unnum0)
		{
		  if (!arp_unnumbered (p0, sw_if_index0, conn_sw_if_index0))
		    goto drop2;
		}
	    }

	  /* We are going to reply to this request, so, in the absence of
	     errors, learn the sender */
	  if (!error0)
	    error0 = arp_learn (vnm, am, sw_if_index0,
				&arp0->ip4_over_ethernet[1]);

	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
					   n_left_to_next, pi0, next0);

	  n_replies_sent += 1;
	  continue;

	drop1:
	  if (arp0->ip4_over_ethernet[0].ip4.as_u32 ==
	      arp0->ip4_over_ethernet[1].ip4.as_u32)
	    {
	      error0 = ETHERNET_ARP_ERROR_gratuitous_arp;
	      goto drop2;
	    }
	  /* See if proxy arp is configured for the address */
	  if (is_request0)
	    {
	      vnet_sw_interface_t *si;
	      u32 this_addr = clib_net_to_host_u32
		(arp0->ip4_over_ethernet[1].ip4.as_u32);
	      u32 fib_index0;

	      si = vnet_get_sw_interface (vnm, sw_if_index0);

	      if (!(si->flags & VNET_SW_INTERFACE_FLAG_PROXY_ARP))
		goto drop2;

	      fib_index0 = vec_elt (im4->fib_index_by_sw_if_index,
				    sw_if_index0);

	      vec_foreach (pa, am->proxy_arps)
	      {
		u32 lo_addr = clib_net_to_host_u32 (pa->lo_addr.as_u32);
		u32 hi_addr = clib_net_to_host_u32 (pa->hi_addr.as_u32);

		/* an ARP request hit in the proxy-arp table? */
		if ((this_addr >= lo_addr && this_addr <= hi_addr) &&
		    (fib_index0 == pa->fib_index))
		  {
		    proxy_src.as_u32 =
		      arp0->ip4_over_ethernet[1].ip4.data_u32;

		    /*
		     * change the interface address to the proxied
		     */
		    if_addr0 = &proxy_src;
		    is_unnum0 = 0;
		    n_proxy_arp_replies_sent++;
		    goto send_reply;
		  }
	      }
	    }

	drop2:

	  next0 = ARP_INPUT_NEXT_DROP;
	  p0->error = node->errors[error0];

	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
					   n_left_to_next, pi0, next0);
	}

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  vlib_error_count (vm, node->node_index,
		    ETHERNET_ARP_ERROR_replies_sent,
		    n_replies_sent - n_proxy_arp_replies_sent);

  vlib_error_count (vm, node->node_index,
		    ETHERNET_ARP_ERROR_proxy_arp_replies_sent,
		    n_proxy_arp_replies_sent);
  return frame->n_vectors;
}

static char *ethernet_arp_error_strings[] = {
#define _(sym,string) string,
  foreach_ethernet_arp_error
#undef _
};

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (arp_input_node, static) =
{
  .function = arp_input,
  .name = "arp-input",
  .vector_size = sizeof (u32),
  .n_errors = ETHERNET_ARP_N_ERROR,
  .error_strings = ethernet_arp_error_strings,
  .n_next_nodes = ARP_INPUT_N_NEXT,
  .next_nodes = {
    [ARP_INPUT_NEXT_DROP] = "error-drop",
    [ARP_INPUT_NEXT_REPLY_TX] = "interface-output",
  },
  .format_buffer = format_ethernet_arp_header,
  .format_trace = format_ethernet_arp_input_trace,
};
/* *INDENT-ON* */

static int
ip4_arp_entry_sort (void *a1, void *a2)
{
  ethernet_arp_ip4_entry_t *e1 = a1;
  ethernet_arp_ip4_entry_t *e2 = a2;

  int cmp;
  vnet_main_t *vnm = vnet_get_main ();

  cmp = vnet_sw_interface_compare (vnm, e1->sw_if_index, e2->sw_if_index);
  if (!cmp)
    cmp = ip4_address_compare (&e1->ip4_address, &e2->ip4_address);
  return cmp;
}

ethernet_arp_ip4_entry_t *
ip4_neighbors_pool (void)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  return am->ip4_entry_pool;
}

ethernet_arp_ip4_entry_t *
ip4_neighbor_entries (u32 sw_if_index)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *n, *ns = 0;

  /* *INDENT-OFF* */
  pool_foreach (n, am->ip4_entry_pool, ({
    if (sw_if_index != ~0 && n->sw_if_index != sw_if_index)
      continue;
    vec_add1 (ns, n[0]);
  }));
  /* *INDENT-ON* */

  if (ns)
    vec_sort_with_function (ns, ip4_arp_entry_sort);
  return ns;
}

static clib_error_t *
show_ip4_arp (vlib_main_t * vm,
	      unformat_input_t * input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e, *es;
  ethernet_proxy_arp_t *pa;
  clib_error_t *error = 0;
  u32 sw_if_index;

  /* Filter entries by interface if given. */
  sw_if_index = ~0;
  (void) unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index);

  es = ip4_neighbor_entries (sw_if_index);
  if (es)
    {
      vlib_cli_output (vm, "%U", format_ethernet_arp_ip4_entry, vnm, 0);
      vec_foreach (e, es)
      {
	vlib_cli_output (vm, "%U", format_ethernet_arp_ip4_entry, vnm, e);
      }
      vec_free (es);
    }

  if (vec_len (am->proxy_arps))
    {
      vlib_cli_output (vm, "Proxy arps enabled for:");
      vec_foreach (pa, am->proxy_arps)
      {
	vlib_cli_output (vm, "Fib_index %d   %U - %U ",
			 pa->fib_index,
			 format_ip4_address, &pa->lo_addr,
			 format_ip4_address, &pa->hi_addr);
      }
    }

  return error;
}

/*?
 * Display all the IPv4 ARP entries.
 *
 * @cliexpar
 * Example of how to display the IPv4 ARP table:
 * @cliexstart{show ip arp}
 *    Time      FIB        IP4       Flags      Ethernet              Interface
 *    346.3028   0       6.1.1.3            de:ad:be:ef:ba:be   GigabitEthernet2/0/0
 *   3077.4271   0       6.1.1.4       S    de:ad:be:ef:ff:ff   GigabitEthernet2/0/0
 *   2998.6409   1       6.2.2.3            de:ad:be:ef:00:01   GigabitEthernet2/0/0
 * Proxy arps enabled for:
 * Fib_index 0   6.0.0.1 - 6.0.0.11
 * @cliexend
 ?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (show_ip4_arp_command, static) = {
  .path = "show ip arp",
  .function = show_ip4_arp,
  .short_help = "show ip arp",
};
/* *INDENT-ON* */

typedef struct
{
  pg_edit_t l2_type, l3_type;
  pg_edit_t n_l2_address_bytes, n_l3_address_bytes;
  pg_edit_t opcode;
  struct
  {
    pg_edit_t ethernet;
    pg_edit_t ip4;
  } ip4_over_ethernet[2];
} pg_ethernet_arp_header_t;

static inline void
pg_ethernet_arp_header_init (pg_ethernet_arp_header_t * p)
{
  /* Initialize fields that are not bit fields in the IP header. */
#define _(f) pg_edit_init (&p->f, ethernet_arp_header_t, f);
  _(l2_type);
  _(l3_type);
  _(n_l2_address_bytes);
  _(n_l3_address_bytes);
  _(opcode);
  _(ip4_over_ethernet[0].ethernet);
  _(ip4_over_ethernet[0].ip4);
  _(ip4_over_ethernet[1].ethernet);
  _(ip4_over_ethernet[1].ip4);
#undef _
}

uword
unformat_pg_arp_header (unformat_input_t * input, va_list * args)
{
  pg_stream_t *s = va_arg (*args, pg_stream_t *);
  pg_ethernet_arp_header_t *p;
  u32 group_index;

  p = pg_create_edit_group (s, sizeof (p[0]), sizeof (ethernet_arp_header_t),
			    &group_index);
  pg_ethernet_arp_header_init (p);

  /* Defaults. */
  pg_edit_set_fixed (&p->l2_type, ETHERNET_ARP_HARDWARE_TYPE_ethernet);
  pg_edit_set_fixed (&p->l3_type, ETHERNET_TYPE_IP4);
  pg_edit_set_fixed (&p->n_l2_address_bytes, 6);
  pg_edit_set_fixed (&p->n_l3_address_bytes, 4);

  if (!unformat (input, "%U: %U/%U -> %U/%U",
		 unformat_pg_edit,
		 unformat_ethernet_arp_opcode_net_byte_order, &p->opcode,
		 unformat_pg_edit,
		 unformat_ethernet_address, &p->ip4_over_ethernet[0].ethernet,
		 unformat_pg_edit,
		 unformat_ip4_address, &p->ip4_over_ethernet[0].ip4,
		 unformat_pg_edit,
		 unformat_ethernet_address, &p->ip4_over_ethernet[1].ethernet,
		 unformat_pg_edit,
		 unformat_ip4_address, &p->ip4_over_ethernet[1].ip4))
    {
      /* Free up any edits we may have added. */
      pg_free_edit_group (s);
      return 0;
    }
  return 1;
}

clib_error_t *
ip4_set_arp_limit (u32 arp_limit)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;

  am->limit_arp_cache_size = arp_limit;
  return 0;
}

/**
 * @brief Control Plane hook to remove an ARP entry
 */
int
vnet_arp_unset_ip4_over_ethernet (vnet_main_t * vnm,
				  u32 sw_if_index,
				  const
				  ethernet_arp_ip4_over_ethernet_address_t *
				  a)
{
  vnet_arp_set_ip4_over_ethernet_rpc_args_t args;

  args.sw_if_index = sw_if_index;
  args.flags = ETHERNET_ARP_ARGS_REMOVE;
  clib_memcpy_fast (&args.a, a, sizeof (*a));

  vl_api_rpc_call_main_thread (set_ip4_over_ethernet_rpc_callback,
			       (u8 *) & args, sizeof (args));
  return 0;
}

/**
 * @brief publish wildcard arp event
 * @param sw_if_index The interface on which the ARP entires are acted
 */
static int
vnet_arp_wc_publish (u32 sw_if_index,
		     const ethernet_arp_ip4_over_ethernet_address_t * a)
{
  vnet_arp_set_ip4_over_ethernet_rpc_args_t args = {
    .flags = ETHERNET_ARP_ARGS_WC_PUB,
    .sw_if_index = sw_if_index,
    .a = *a
  };

  vl_api_rpc_call_main_thread (set_ip4_over_ethernet_rpc_callback,
			       (u8 *) & args, sizeof (args));
  return 0;
}

static void
vnet_arp_wc_publish_internal (vnet_main_t * vnm,
			      vnet_arp_set_ip4_over_ethernet_rpc_args_t *
			      args)
{
  vlib_main_t *vm = vlib_get_main ();
  ethernet_arp_main_t *am = &ethernet_arp_main;
  uword ni = am->wc_ip4_arp_publisher_node;
  uword et = am->wc_ip4_arp_publisher_et;

  if (ni == (uword) ~ 0)
    return;
  wc_arp_report_t *r =
    vlib_process_signal_event_data (vm, ni, et, 1, sizeof *r);
  r->ip4 = args->a.ip4.as_u32;
  r->sw_if_index = args->sw_if_index;
  memcpy (r->mac, args->a.ethernet, sizeof r->mac);
}

void
wc_arp_set_publisher_node (uword node_index, uword event_type)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  am->wc_ip4_arp_publisher_node = node_index;
  am->wc_ip4_arp_publisher_et = event_type;
}

static void
arp_entry_free (ethernet_arp_interface_t * eai, ethernet_arp_ip4_entry_t * e);

static int
vnet_arp_flush_ip4_over_ethernet_internal (vnet_main_t * vnm,
					   vnet_arp_set_ip4_over_ethernet_rpc_args_t
					   * args)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  ethernet_arp_interface_t *eai;

  if (vec_len (am->ethernet_arp_by_sw_if_index) <= args->sw_if_index)
    return 0;

  eai = &am->ethernet_arp_by_sw_if_index[args->sw_if_index];

  e = arp_entry_find (eai, &args->a.ip4);

  if (NULL != e)
    {
      adj_nbr_walk_nh4 (e->sw_if_index,
			&e->ip4_address, arp_mk_incomplete_walk, e);

      /*
       * The difference between flush and unset, is that an unset
       * means delete for static and dynamic entries. A flush
       * means delete only for dynamic. Flushing is what the DP
       * does in response to interface events. unset is only done
       * by the control plane.
       */
      if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC)
	{
	  e->flags &= ~ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC;
	}
      else if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC)
	{
	  arp_entry_free (eai, e);
	}
    }
  return (0);
}

/*
 * arp_add_del_interface_address
 *
 * callback when an interface address is added or deleted
 */
static void
arp_add_del_interface_address (ip4_main_t * im,
			       uword opaque,
			       u32 sw_if_index,
			       ip4_address_t * address,
			       u32 address_length,
			       u32 if_address_index, u32 is_del)
{
  /*
   * Flush the ARP cache of all entries covered by the address
   * that is being removed.
   */
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;

  if (vec_len (am->ethernet_arp_by_sw_if_index) <= sw_if_index)
    return;

  if (is_del)
    {
      ethernet_arp_interface_t *eai;
      u32 i, *to_delete = 0;
      hash_pair_t *pair;

      eai = &am->ethernet_arp_by_sw_if_index[sw_if_index];

      /* *INDENT-OFF* */
      hash_foreach_pair (pair, eai->arp_entries,
      ({
	e = pool_elt_at_index(am->ip4_entry_pool,
			      pair->value[0]);
	if (ip4_destination_matches_route (im, &e->ip4_address,
					   address, address_length))
	  {
	    vec_add1 (to_delete, e - am->ip4_entry_pool);
	  }
      }));
      /* *INDENT-ON* */

      for (i = 0; i < vec_len (to_delete); i++)
	{
	  e = pool_elt_at_index (am->ip4_entry_pool, to_delete[i]);

	  vnet_arp_set_ip4_over_ethernet_rpc_args_t delme = {
	    .a.ip4.as_u32 = e->ip4_address.as_u32,
	    .sw_if_index = e->sw_if_index,
	    .flags = ETHERNET_ARP_ARGS_FLUSH,
	  };
	  clib_memcpy_fast (&delme.a.ethernet, e->ethernet_address, 6);

	  vnet_arp_flush_ip4_over_ethernet_internal (vnet_get_main (),
						     &delme);
	}

      vec_free (to_delete);
    }
}

static void
arp_table_bind (ip4_main_t * im,
		uword opaque,
		u32 sw_if_index, u32 new_fib_index, u32 old_fib_index)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_interface_t *eai;
  ethernet_arp_ip4_entry_t *e;
  hash_pair_t *pair;

  /*
   * the IP table that the interface is bound to has changed.
   * reinstall all the adj fibs.
   */

  if (vec_len (am->ethernet_arp_by_sw_if_index) <= sw_if_index)
    return;

  eai = &am->ethernet_arp_by_sw_if_index[sw_if_index];

  /* *INDENT-OFF* */
  hash_foreach_pair (pair, eai->arp_entries,
  ({
    e = pool_elt_at_index(am->ip4_entry_pool,
                          pair->value[0]);
    /*
     * remove the adj-fib from the old table and add to the new
     */
    arp_adj_fib_remove(e, old_fib_index);
    arp_adj_fib_add(e, new_fib_index);
  }));
  /* *INDENT-ON* */

}

static clib_error_t *
ethernet_arp_init (vlib_main_t * vm)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ip4_main_t *im = &ip4_main;
  clib_error_t *error;
  pg_node_t *pn;

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

  ethernet_register_input_type (vm, ETHERNET_TYPE_ARP, arp_input_node.index);

  pn = pg_get_node (arp_input_node.index);
  pn->unformat_edit = unformat_pg_arp_header;

  am->opcode_by_name = hash_create_string (0, sizeof (uword));
#define _(o) hash_set_mem (am->opcode_by_name, #o, ETHERNET_ARP_OPCODE_##o);
  foreach_ethernet_arp_opcode;
#undef _

  /* $$$ configurable */
  am->limit_arp_cache_size = 50000;

  am->pending_resolutions_by_address = hash_create (0, sizeof (uword));
  am->mac_changes_by_address = hash_create (0, sizeof (uword));
  am->wc_ip4_arp_publisher_node = (uword) ~ 0;

  /* don't trace ARP error packets */
  {
    vlib_node_runtime_t *rt =
      vlib_node_get_runtime (vm, arp_input_node.index);

#define _(a,b)                                  \
    vnet_pcap_drop_trace_filter_add_del         \
        (rt->errors[ETHERNET_ARP_ERROR_##a],    \
         1 /* is_add */);
    foreach_ethernet_arp_error
#undef _
  }

  ip4_add_del_interface_address_callback_t cb;
  cb.function = arp_add_del_interface_address;
  cb.function_opaque = 0;
  vec_add1 (im->add_del_interface_address_callbacks, cb);

  ip4_table_bind_callback_t cbt;
  cbt.function = arp_table_bind;
  cbt.function_opaque = 0;
  vec_add1 (im->table_bind_callbacks, cbt);

  return 0;
}

VLIB_INIT_FUNCTION (ethernet_arp_init);

static void
arp_entry_free (ethernet_arp_interface_t * eai, ethernet_arp_ip4_entry_t * e)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;

  arp_adj_fib_remove
    (e, ip4_fib_table_get_index_for_sw_if_index (e->sw_if_index));
  hash_unset (eai->arp_entries, e->ip4_address.as_u32);
  pool_put (am->ip4_entry_pool, e);
}

static inline int
vnet_arp_unset_ip4_over_ethernet_internal (vnet_main_t * vnm,
					   vnet_arp_set_ip4_over_ethernet_rpc_args_t
					   * args)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  ethernet_arp_interface_t *eai;

  if (vec_len (am->ethernet_arp_by_sw_if_index) <= args->sw_if_index)
    return 0;

  eai = &am->ethernet_arp_by_sw_if_index[args->sw_if_index];

  e = arp_entry_find (eai, &args->a.ip4);

  if (NULL != e)
    {
      adj_nbr_walk_nh4 (e->sw_if_index,
			&e->ip4_address, arp_mk_incomplete_walk, e);
      arp_entry_free (eai, e);
    }

  return 0;
}


static int
vnet_arp_populate_ip4_over_ethernet_internal (vnet_main_t * vnm,
					      vnet_arp_set_ip4_over_ethernet_rpc_args_t
					      * args)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  ethernet_arp_interface_t *eai;

  vec_validate (am->ethernet_arp_by_sw_if_index, args->sw_if_index);
  eai = &am->ethernet_arp_by_sw_if_index[args->sw_if_index];

  e = arp_entry_find (eai, &args->a.ip4);

  if (NULL != e)
    {
      adj_nbr_walk_nh4 (e->sw_if_index,
			&e->ip4_address, arp_mk_complete_walk, e);
    }
  return (0);
}

static void
set_ip4_over_ethernet_rpc_callback (vnet_arp_set_ip4_over_ethernet_rpc_args_t
				    * a)
{
  vnet_main_t *vm = vnet_get_main ();
  ASSERT (vlib_get_thread_index () == 0);

  if (a->flags & ETHERNET_ARP_ARGS_REMOVE)
    vnet_arp_unset_ip4_over_ethernet_internal (vm, a);
  else if (a->flags & ETHERNET_ARP_ARGS_FLUSH)
    vnet_arp_flush_ip4_over_ethernet_internal (vm, a);
  else if (a->flags & ETHERNET_ARP_ARGS_POPULATE)
    vnet_arp_populate_ip4_over_ethernet_internal (vm, a);
  else if (a->flags & ETHERNET_ARP_ARGS_WC_PUB)
    vnet_arp_wc_publish_internal (vm, a);
  else
    vnet_arp_set_ip4_over_ethernet_internal (vm, a);
}

/**
 * @brief Invoked when the interface's admin state changes
 */
static clib_error_t *
ethernet_arp_sw_interface_up_down (vnet_main_t * vnm,
				   u32 sw_if_index, u32 flags)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  u32 i, *to_update = 0;

  /* *INDENT-OFF* */
  pool_foreach (e, am->ip4_entry_pool,
  ({
    if (e->sw_if_index == sw_if_index)
      vec_add1 (to_update,
		e - am->ip4_entry_pool);
  }));
  /* *INDENT-ON* */

  for (i = 0; i < vec_len (to_update); i++)
    {
      e = pool_elt_at_index (am->ip4_entry_pool, to_update[i]);

      vnet_arp_set_ip4_over_ethernet_rpc_args_t update_me = {
	.a.ip4.as_u32 = e->ip4_address.as_u32,
	.sw_if_index = e->sw_if_index,
      };

      clib_memcpy_fast (&update_me.a.ethernet, e->ethernet_address, 6);

      if (flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP)
	{
	  update_me.flags = ETHERNET_ARP_ARGS_POPULATE;
	  vnet_arp_populate_ip4_over_ethernet_internal (vnm, &update_me);
	}
      else
	{
	  update_me.flags = ETHERNET_ARP_ARGS_FLUSH;
	  vnet_arp_flush_ip4_over_ethernet_internal (vnm, &update_me);
	}
    }
  vec_free (to_update);

  return 0;
}

VNET_SW_INTERFACE_ADMIN_UP_DOWN_FUNCTION (ethernet_arp_sw_interface_up_down);

static void
increment_ip4_and_mac_address (ethernet_arp_ip4_over_ethernet_address_t * a)
{
  u8 old;
  int i;

  for (i = 3; i >= 0; i--)
    {
      old = a->ip4.as_u8[i];
      a->ip4.as_u8[i] += 1;
      if (old < a->ip4.as_u8[i])
	break;
    }

  for (i = 5; i >= 0; i--)
    {
      old = a->ethernet[i];
      a->ethernet[i] += 1;
      if (old < a->ethernet[i])
	break;
    }
}

int
vnet_arp_set_ip4_over_ethernet (vnet_main_t * vnm,
				u32 sw_if_index,
				const ethernet_arp_ip4_over_ethernet_address_t
				* a, int is_static, int is_no_fib_entry)
{
  vnet_arp_set_ip4_over_ethernet_rpc_args_t args;

  args.sw_if_index = sw_if_index;
  args.is_static = is_static;
  args.is_no_fib_entry = is_no_fib_entry;
  args.flags = 0;
  clib_memcpy_fast (&args.a, a, sizeof (*a));

  vl_api_rpc_call_main_thread (set_ip4_over_ethernet_rpc_callback,
			       (u8 *) & args, sizeof (args));
  return 0;
}

void
proxy_arp_walk (proxy_arp_walk_t cb, void *data)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_proxy_arp_t *pa;

  vec_foreach (pa, am->proxy_arps)
  {
    if (!cb (&pa->lo_addr, &pa->hi_addr, pa->fib_index, data))
      break;
  }
}

int
vnet_proxy_arp_add_del (ip4_address_t * lo_addr,
			ip4_address_t * hi_addr, u32 fib_index, int is_del)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_proxy_arp_t *pa;
  u32 found_at_index = ~0;

  vec_foreach (pa, am->proxy_arps)
  {
    if (pa->lo_addr.as_u32 == lo_addr->as_u32 &&
	pa->hi_addr.as_u32 == hi_addr->as_u32 && pa->fib_index == fib_index)
      {
	found_at_index = pa - am->proxy_arps;
	break;
      }
  }

  if (found_at_index != ~0)
    {
      /* Delete, otherwise it's already in the table */
      if (is_del)
	vec_delete (am->proxy_arps, 1, found_at_index);
      return 0;
    }
  /* delete, no such entry */
  if (is_del)
    return VNET_API_ERROR_NO_SUCH_ENTRY;

  /* add, not in table */
  vec_add2 (am->proxy_arps, pa, 1);
  pa->lo_addr.as_u32 = lo_addr->as_u32;
  pa->hi_addr.as_u32 = hi_addr->as_u32;
  pa->fib_index = fib_index;
  return 0;
}

/*
 * Remove any proxy arp entries asdociated with the
 * specificed fib.
 */
int
vnet_proxy_arp_fib_reset (u32 fib_id)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_proxy_arp_t *pa;
  u32 *entries_to_delete = 0;
  u32 fib_index;
  int i;

  fib_index = fib_table_find (FIB_PROTOCOL_IP4, fib_id);
  if (~0 == fib_index)
    return VNET_API_ERROR_NO_SUCH_ENTRY;

  vec_foreach (pa, am->proxy_arps)
  {
    if (pa->fib_index == fib_index)
      {
	vec_add1 (entries_to_delete, pa - am->proxy_arps);
      }
  }

  for (i = 0; i < vec_len (entries_to_delete); i++)
    {
      vec_delete (am->proxy_arps, 1, entries_to_delete[i]);
    }

  vec_free (entries_to_delete);

  return 0;
}

static clib_error_t *
ip_arp_add_del_command_fn (vlib_main_t * vm,
			   unformat_input_t * input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  u32 sw_if_index;
  ethernet_arp_ip4_over_ethernet_address_t lo_addr, hi_addr, addr;
  int addr_valid = 0;
  int is_del = 0;
  int count = 1;
  u32 fib_index = 0;
  u32 fib_id;
  int is_static = 0;
  int is_no_fib_entry = 0;
  int is_proxy = 0;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      /* set ip arp TenGigE1/1/0/1 1.2.3.4 aa:bb:... or aabb.ccdd... */
      if (unformat (input, "%U %U %U",
		    unformat_vnet_sw_interface, vnm, &sw_if_index,
		    unformat_ip4_address, &addr.ip4,
		    unformat_ethernet_address, &addr.ethernet))
	addr_valid = 1;

      else if (unformat (input, "delete") || unformat (input, "del"))
	is_del = 1;

      else if (unformat (input, "static"))
	is_static = 1;

      else if (unformat (input, "no-fib-entry"))
	is_no_fib_entry = 1;

      else if (unformat (input, "count %d", &count))
	;

      else if (unformat (input, "fib-id %d", &fib_id))
	{
	  fib_index = fib_table_find (FIB_PROTOCOL_IP4, fib_id);

	  if (~0 == fib_index)
	    return clib_error_return (0, "fib ID %d doesn't exist\n", fib_id);
	}

      else if (unformat (input, "proxy %U - %U",
			 unformat_ip4_address, &lo_addr.ip4,
			 unformat_ip4_address, &hi_addr.ip4))
	is_proxy = 1;
      else
	break;
    }

  if (is_proxy)
    {
      (void) vnet_proxy_arp_add_del (&lo_addr.ip4, &hi_addr.ip4,
				     fib_index, is_del);
      return 0;
    }

  if (addr_valid)
    {
      int i;

      for (i = 0; i < count; i++)
	{
	  if (is_del == 0)
	    {
	      uword event_type, *event_data = 0;

	      /* Park the debug CLI until the arp entry is installed */
	      vnet_register_ip4_arp_resolution_event
		(vnm, &addr.ip4, vlib_current_process (vm),
		 1 /* type */ , 0 /* data */ );

	      vnet_arp_set_ip4_over_ethernet
		(vnm, sw_if_index, &addr, is_static, is_no_fib_entry);

	      vlib_process_wait_for_event (vm);
	      event_type = vlib_process_get_events (vm, &event_data);
	      vec_reset_length (event_data);
	      if (event_type != 1)
		clib_warning ("event type %d unexpected", event_type);
	    }
	  else
	    vnet_arp_unset_ip4_over_ethernet (vnm, sw_if_index, &addr);

	  increment_ip4_and_mac_address (&addr);
	}
    }
  else
    {
      return clib_error_return (0, "unknown input `%U'",
				format_unformat_error, input);
    }

  return 0;
}

/* *INDENT-OFF* */
/*?
 * Add or delete IPv4 ARP cache entries.
 *
 * @note 'set ip arp' options (e.g. delete, static, 'fib-id <id>',
 * 'count <number>', 'interface ip4_addr mac_addr') can be added in
 * any order and combination.
 *
 * @cliexpar
 * @parblock
 * Add or delete IPv4 ARP cache entries as follows. MAC Address can be in
 * either aa:bb:cc:dd:ee:ff format or aabb.ccdd.eeff format.
 * @cliexcmd{set ip arp GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 * @cliexcmd{set ip arp delete GigabitEthernet2/0/0 6.0.0.3 de:ad:be:ef:ba:be}
 *
 * To add or delete an IPv4 ARP cache entry to or from a specific fib
 * table:
 * @cliexcmd{set ip arp fib-id 1 GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 * @cliexcmd{set ip arp fib-id 1 delete GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 *
 * Add or delete IPv4 static ARP cache entries as follows:
 * @cliexcmd{set ip arp static GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 * @cliexcmd{set ip arp static delete GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 *
 * For testing / debugging purposes, the 'set ip arp' command can add or
 * delete multiple entries. Supply the 'count N' parameter:
 * @cliexcmd{set ip arp count 10 GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 * @endparblock
 ?*/
VLIB_CLI_COMMAND (ip_arp_add_del_command, static) = {
  .path = "set ip arp",
  .short_help =
  "set ip arp [del] <intfc> <ip-address> <mac-address> [static] [no-fib-entry] [count <count>] [fib-id <fib-id>] [proxy <lo-addr> - <hi-addr>]",
  .function = ip_arp_add_del_command_fn,
};
/* *INDENT-ON* */

static clib_error_t *
set_int_proxy_arp_command_fn (vlib_main_t * vm,
			      unformat_input_t *
			      input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  u32 sw_if_index;
  vnet_sw_interface_t *si;
  int enable = 0;
  int intfc_set = 0;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "%U", unformat_vnet_sw_interface,
		    vnm, &sw_if_index))
	intfc_set = 1;
      else if (unformat (input, "enable") || unformat (input, "on"))
	enable = 1;
      else if (unformat (input, "disable") || unformat (input, "off"))
	enable = 0;
      else
	break;
    }

  if (intfc_set == 0)
    return clib_error_return (0, "unknown input '%U'",
			      format_unformat_error, input);

  si = vnet_get_sw_interface (vnm, sw_if_index);
  ASSERT (si);
  if (enable)
    si->flags |= VNET_SW_INTERFACE_FLAG_PROXY_ARP;
  else
    si->flags &= ~VNET_SW_INTERFACE_FLAG_PROXY_ARP;

  return 0;
}

/* *INDENT-OFF* */
/*?
 * Enable proxy-arp on an interface. The vpp stack will answer ARP
 * requests for the indicated address range. Multiple proxy-arp
 * ranges may be provisioned.
 *
 * @note Proxy ARP as a technology is infamous for blackholing traffic.
 * Also, the underlying implementation has not been performance-tuned.
 * Avoid creating an unnecessarily large set of ranges.
 *
 * @cliexpar
 * To enable proxy arp on a range of addresses, use:
 * @cliexcmd{set ip arp proxy 6.0.0.1 - 6.0.0.11}
 * Append 'del' to delete a range of proxy ARP addresses:
 * @cliexcmd{set ip arp proxy 6.0.0.1 - 6.0.0.11 del}
 * You must then specifically enable proxy arp on individual interfaces:
 * @cliexcmd{set interface proxy-arp GigabitEthernet0/8/0 enable}
 * To disable proxy arp on an individual interface:
 * @cliexcmd{set interface proxy-arp GigabitEthernet0/8/0 disable}
 ?*/
VLIB_CLI_COMMAND (set_int_proxy_enable_command, static) = {
  .path = "set interface proxy-arp",
  .short_help =
  "set interface proxy-arp <intfc> [enable|disable]",
  .function = set_int_proxy_arp_command_fn,
};
/* *INDENT-ON* */


/*
 * ARP/ND Termination in a L2 Bridge Domain based on IP4/IP6 to MAC
 * hash tables mac_by_ip4 and mac_by_ip6 for each BD.
 */
typedef enum
{
  ARP_TERM_NEXT_L2_OUTPUT,
  ARP_TERM_NEXT_DROP,
  ARP_TERM_N_NEXT,
} arp_term_next_t;

u32 arp_term_next_node_index[32];

static uword
arp_term_l2bd (vlib_main_t * vm,
	       vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  l2input_main_t *l2im = &l2input_main;
  u32 n_left_from, next_index, *from, *to_next;
  u32 n_replies_sent = 0;
  u16 last_bd_index = ~0;
  l2_bridge_domain_t *last_bd_config = 0;
  l2_input_config_t *cfg0;

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  vlib_buffer_t *p0;
	  ethernet_header_t *eth0;
	  ethernet_arp_header_t *arp0;
	  ip6_header_t *iph0;
	  u8 *l3h0;
	  u32 pi0, error0, next0, sw_if_index0;
	  u16 ethertype0;
	  u16 bd_index0;
	  u32 ip0;
	  u8 *macp0;

	  pi0 = from[0];
	  to_next[0] = pi0;
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;

	  p0 = vlib_get_buffer (vm, pi0);
	  // Terminate only local (SHG == 0) ARP
	  if (vnet_buffer (p0)->l2.shg != 0)
	    goto next_l2_feature;

	  eth0 = vlib_buffer_get_current (p0);
	  l3h0 = (u8 *) eth0 + vnet_buffer (p0)->l2.l2_len;
	  ethertype0 = clib_net_to_host_u16 (*(u16 *) (l3h0 - 2));
	  arp0 = (ethernet_arp_header_t *) l3h0;

	  if (ethertype0 != ETHERNET_TYPE_ARP)
	    goto check_ip6_nd;

	  if ((arp0->opcode !=
	       clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_request)) &&
	      (arp0->opcode !=
	       clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply)))
	    goto check_ip6_nd;

	  /* Must be ARP request/reply packet here */
	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
			     (p0->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      u8 *t0 = vlib_add_trace (vm, node, p0,
				       sizeof (ethernet_arp_input_trace_t));
	      clib_memcpy_fast (t0, l3h0,
				sizeof (ethernet_arp_input_trace_t));
	    }

	  error0 = 0;
	  error0 =
	    (arp0->l2_type !=
	     clib_net_to_host_u16 (ETHERNET_ARP_HARDWARE_TYPE_ethernet)
	     ? ETHERNET_ARP_ERROR_l2_type_not_ethernet : error0);
	  error0 =
	    (arp0->l3_type !=
	     clib_net_to_host_u16 (ETHERNET_TYPE_IP4) ?
	     ETHERNET_ARP_ERROR_l3_type_not_ip4 : error0);

	  sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX];

	  if (error0)
	    goto drop;

	  /* Trash ARP packets whose ARP-level source addresses do not
	     match, or if requester address is mcast */
	  if (PREDICT_FALSE
	      (memcmp (eth0->src_address, arp0->ip4_over_ethernet[0].ethernet,
		       sizeof (eth0->src_address)) ||
	       ethernet_address_cast (arp0->ip4_over_ethernet[0].ethernet)))
	    {
	      /* VRRP virtual MAC may be different to SMAC in ARP reply */
	      if (memcmp (arp0->ip4_over_ethernet[0].ethernet, vrrp_prefix,
			  sizeof (vrrp_prefix)))
		{
		  error0 = ETHERNET_ARP_ERROR_l2_address_mismatch;
		  goto drop;
		}
	    }
	  if (PREDICT_FALSE
	      (ip4_address_is_multicast (&arp0->ip4_over_ethernet[0].ip4)))
	    {
	      error0 = ETHERNET_ARP_ERROR_l3_src_address_not_local;
	      goto drop;
	    }

	  /* Check if anyone want ARP request events for L2 BDs */
	  {
	    ethernet_arp_main_t *am = &ethernet_arp_main;
	    if (am->wc_ip4_arp_publisher_node != (uword) ~ 0)
	      vnet_arp_wc_publish (sw_if_index0, &arp0->ip4_over_ethernet[0]);
	  }

	  /* lookup BD mac_by_ip4 hash table for MAC entry */
	  ip0 = arp0->ip4_over_ethernet[1].ip4.as_u32;
	  bd_index0 = vnet_buffer (p0)->l2.bd_index;
	  if (PREDICT_FALSE ((bd_index0 != last_bd_index)
			     || (last_bd_index == (u16) ~ 0)))
	    {
	      last_bd_index = bd_index0;
	      last_bd_config = vec_elt_at_index (l2im->bd_configs, bd_index0);
	    }
	  macp0 = (u8 *) hash_get (last_bd_config->mac_by_ip4, ip0);

	  if (PREDICT_FALSE (!macp0))
	    goto next_l2_feature;	/* MAC not found */

	  /* MAC found, send ARP reply -
	     Convert ARP request packet to ARP reply */
	  arp0->opcode = clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply);
	  arp0->ip4_over_ethernet[1] = arp0->ip4_over_ethernet[0];
	  arp0->ip4_over_ethernet[0].ip4.as_u32 = ip0;
	  clib_memcpy_fast (arp0->ip4_over_ethernet[0].ethernet, macp0, 6);
	  clib_memcpy_fast (eth0->dst_address, eth0->src_address, 6);
	  clib_memcpy_fast (eth0->src_address, macp0, 6);
	  n_replies_sent += 1;

	output_response:
	  /* For BVI, need to use l2-fwd node to send ARP reply as
	     l2-output node cannot output packet to BVI properly */
	  cfg0 = vec_elt_at_index (l2im->configs, sw_if_index0);
	  if (PREDICT_FALSE (cfg0->bvi))
	    {
	      vnet_buffer (p0)->l2.feature_bitmap |= L2INPUT_FEAT_FWD;
	      vnet_buffer (p0)->sw_if_index[VLIB_RX] = 0;
	      goto next_l2_feature;
	    }

	  /* Send ARP/ND reply back out input interface through l2-output */
	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
	  next0 = ARP_TERM_NEXT_L2_OUTPUT;
	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
					   to_next, n_left_to_next, pi0,
					   next0);
	  continue;

	check_ip6_nd:
	  /* IP6 ND event notification or solicitation handling to generate
	     local response instead of flooding */
	  iph0 = (ip6_header_t *) l3h0;
	  if (PREDICT_FALSE (ethertype0 == ETHERNET_TYPE_IP6 &&
			     iph0->protocol == IP_PROTOCOL_ICMP6 &&
			     !ip6_address_is_unspecified
			     (&iph0->src_address)))
	    {
	      sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX];
	      if (vnet_ip6_nd_term
		  (vm, node, p0, eth0, iph0, sw_if_index0,
		   vnet_buffer (p0)->l2.bd_index))
		goto output_response;
	    }

	next_l2_feature:
	  {
	    next0 = vnet_l2_feature_next (p0, arp_term_next_node_index,
					  L2INPUT_FEAT_ARP_TERM);
	    vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
					     to_next, n_left_to_next,
					     pi0, next0);
	    continue;
	  }

	drop:
	  if (0 == arp0->ip4_over_ethernet[0].ip4.as_u32 ||
	      (arp0->ip4_over_ethernet[0].ip4.as_u32 ==
	       arp0->ip4_over_ethernet[1].ip4.as_u32))
	    {
	      error0 = ETHERNET_ARP_ERROR_gratuitous_arp;
	    }
	  next0 = ARP_TERM_NEXT_DROP;
	  p0->error = node->errors[error0];

	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
					   to_next, n_left_to_next, pi0,
					   next0);
	}

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  vlib_error_count (vm, node->node_index,
		    ETHERNET_ARP_ERROR_replies_sent, n_replies_sent);
  return frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (arp_term_l2bd_node, static) = {
  .function = arp_term_l2bd,
  .name = "arp-term-l2bd",
  .vector_size = sizeof (u32),
  .n_errors = ETHERNET_ARP_N_ERROR,
  .error_strings = ethernet_arp_error_strings,
  .n_next_nodes = ARP_TERM_N_NEXT,
  .next_nodes = {
    [ARP_TERM_NEXT_L2_OUTPUT] = "l2-output",
    [ARP_TERM_NEXT_DROP] = "error-drop",
  },
  .format_buffer = format_ethernet_arp_header,
  .format_trace = format_arp_term_input_trace,
};
/* *INDENT-ON* */

clib_error_t *
arp_term_init (vlib_main_t * vm)
{
  // Initialize the feature next-node indexes
  feat_bitmap_init_next_nodes (vm,
			       arp_term_l2bd_node.index,
			       L2INPUT_N_FEAT,
			       l2input_get_feat_names (),
			       arp_term_next_node_index);
  return 0;
}

VLIB_INIT_FUNCTION (arp_term_init);

void
change_arp_mac (u32 sw_if_index, ethernet_arp_ip4_entry_t * e)
{
  if (e->sw_if_index == sw_if_index)
    {
      adj_nbr_walk_nh4 (e->sw_if_index,
			&e->ip4_address, arp_mk_complete_walk, e);
    }
}

void
ethernet_arp_change_mac (u32 sw_if_index)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  adj_index_t ai;

  /* *INDENT-OFF* */
  pool_foreach (e, am->ip4_entry_pool,
  ({
    change_arp_mac (sw_if_index, e);
  }));
  /* *INDENT-ON* */

  ai = adj_glean_get (FIB_PROTOCOL_IP4, sw_if_index);

  if (ADJ_INDEX_INVALID != ai)
    adj_glean_update_rewrite (ai);
}

void
send_ip4_garp (vlib_main_t * vm, u32 sw_if_index)
{
  ip4_main_t *i4m = &ip4_main;
  ip4_address_t *ip4_addr = ip4_interface_first_address (i4m, sw_if_index, 0);

  send_ip4_garp_w_addr (vm, ip4_addr, sw_if_index);
}

void
send_ip4_garp_w_addr (vlib_main_t * vm,
		      const ip4_address_t * ip4_addr, u32 sw_if_index)
{
  ip4_main_t *i4m = &ip4_main;
  vnet_main_t *vnm = vnet_get_main ();
  u8 *rewrite, rewrite_len;
  vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);

  if (ip4_addr)
    {
      clib_warning ("Sending GARP for IP4 address %U on sw_if_idex %d",
		    format_ip4_address, ip4_addr, sw_if_index);

      /* Form GARP packet for output - Gratuitous ARP is an ARP request packet
         where the interface IP/MAC pair is used for both source and request
         MAC/IP pairs in the request */
      u32 bi = 0;
      ethernet_arp_header_t *h = vlib_packet_template_get_packet
	(vm, &i4m->ip4_arp_request_packet_template, &bi);

      if (!h)
	return;

      clib_memcpy_fast (h->ip4_over_ethernet[0].ethernet, hi->hw_address,
			sizeof (h->ip4_over_ethernet[0].ethernet));
      clib_memcpy_fast (h->ip4_over_ethernet[1].ethernet, hi->hw_address,
			sizeof (h->ip4_over_ethernet[1].ethernet));
      h->ip4_over_ethernet[0].ip4 = ip4_addr[0];
      h->ip4_over_ethernet[1].ip4 = ip4_addr[0];

      /* Setup MAC header with ARP Etype and broadcast DMAC */
      vlib_buffer_t *b = vlib_get_buffer (vm, bi);
      rewrite =
	ethernet_build_rewrite (vnm, sw_if_index, VNET_LINK_ARP,
				VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST);
      rewrite_len = vec_len (rewrite);
      vlib_buffer_advance (b, -rewrite_len);
      ethernet_header_t *e = vlib_buffer_get_current (b);
      clib_memcpy_fast (e->dst_address, rewrite, rewrite_len);
      vec_free (rewrite);

      /* Send GARP packet out the specified interface */
      vnet_buffer (b)->sw_if_index[VLIB_RX] =
	vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
      vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
      u32 *to_next = vlib_frame_vector_args (f);
      to_next[0] = bi;
      f->n_vectors = 1;
      vlib_put_frame_to_node (vm, hi->output_node_index, f);
    }
}

/*
 * Remove any arp entries asociated with the specificed interface
 */
void
vnet_arp_delete_sw_interface (vnet_main_t * vnm, u32 sw_if_index, u32 is_add)
{
  if (!is_add && sw_if_index != ~0)
    {
      ethernet_arp_main_t *am = &ethernet_arp_main;
      ethernet_arp_ip4_entry_t *e;
      /* *INDENT-OFF* */
      pool_foreach (e, am->ip4_entry_pool, ({
        if (e->sw_if_index != sw_if_index)
          continue;
        vnet_arp_set_ip4_over_ethernet_rpc_args_t args = { .sw_if_index = sw_if_index,
                                                           .a.ip4 = e->ip4_address };
        vnet_arp_unset_ip4_over_ethernet_internal (vnm, &args);
      }));
      /* *INDENT-ON* */
    }
}

VNET_SW_INTERFACE_ADD_DEL_FUNCTION (vnet_arp_delete_sw_interface);

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