src/vnet/ip-neighbor/ip4_neighbor.c - fdio/vpp - Gitiles

 /*
  * 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.
  */
 /*
  * ip/ip4_forward.c: IP v4 forwarding
  *
  * Copyright (c) 2008 Eliot Dresselhaus
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, sublicense, and/or sell copies of the Software, and to
  * permit persons to whom the Software is furnished to do so, subject to
  * the following conditions:
  *
  * The above copyright notice and this permission notice shall be
  * included in all copies or substantial portions of the Software.
  *
  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */

 #include <vnet/ip-neighbor/ip4_neighbor.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/util/throttle.h>
 #include <vnet/fib/fib_sas.h>

 /** ARP throttling */
 static throttle_t arp_throttle;

 VLIB_REGISTER_LOG_CLASS (ip4_neighbor_log, static) = {
   .class_name = "ip4",
   .subclass_name = "neighbor",
 };

 #define log_debug(fmt, ...)                                                   \
   vlib_log_debug (ip4_neighbor_log.class, fmt, __VA_ARGS__)

 void
 ip4_neighbor_probe_dst (u32 sw_if_index, const ip4_address_t * dst)
 {
   ip4_address_t src;
   adj_index_t ai;

   /* any glean will do, it's just for the rewrite */
   ai = adj_glean_get (FIB_PROTOCOL_IP4, sw_if_index, NULL);

   if (ADJ_INDEX_INVALID != ai && fib_sas4_get (sw_if_index, dst, &src))
     ip4_neighbor_probe (vlib_get_main (),
 			vnet_get_main (), adj_get (ai), &src, dst);
 }

 void
 ip4_neighbor_advertise (vlib_main_t * vm,
 			vnet_main_t * vnm,
 			u32 sw_if_index, const ip4_address_t * addr)
 {
   vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
   ip4_main_t *i4m = &ip4_main;
   u8 *rewrite, rewrite_len;
   ip4_address_t tmp;

   if (NULL == addr)
     {
       if (fib_sas4_get (sw_if_index, NULL, &tmp))
 	addr = &tmp;
     }

   if (addr)
     {
       log_debug ("Sending GARP for IP4 address %U on sw_if_idex %d",
 		 format_ip4_address, 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;

       mac_address_from_bytes (&h->ip4_over_ethernet[0].mac, hi->hw_address);
       mac_address_from_bytes (&h->ip4_over_ethernet[1].mac, hi->hw_address);
       h->ip4_over_ethernet[0].ip4 = addr[0];
       h->ip4_over_ethernet[1].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);
     }
 }

 always_inline uword
 ip4_arp_inline (vlib_main_t * vm,
 		vlib_node_runtime_t * node,
 		vlib_frame_t * frame, int is_glean)
 {
   vnet_main_t *vnm = vnet_get_main ();
   u32 *from, *to_next_drop;
   uword n_left_from, n_left_to_next_drop, next_index;
   u32 thread_index = vm->thread_index;
   u64 seed;

   if (node->flags & VLIB_NODE_FLAG_TRACE)
     ip4_forward_next_trace (vm, node, frame, VLIB_TX);

   seed = throttle_seed (&arp_throttle, thread_index, vlib_time_now (vm));

   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
   next_index = node->cached_next_index;
   if (next_index == IP4_ARP_NEXT_DROP)
     next_index = IP4_ARP_N_NEXT;	/* point to first interface */

   while (n_left_from > 0)
     {
       vlib_get_next_frame (vm, node, IP4_ARP_NEXT_DROP,
 			   to_next_drop, n_left_to_next_drop);

       while (n_left_from > 0 && n_left_to_next_drop > 0)
 	{
 	  u32 pi0, adj_index0, sw_if_index0;
 	  ip4_address_t resolve0, src0;
 	  vlib_buffer_t *p0, *b0;
 	  ip_adjacency_t *adj0;
 	  u64 r0;

 	  pi0 = from[0];
 	  p0 = vlib_get_buffer (vm, pi0);

 	  from += 1;
 	  n_left_from -= 1;
 	  to_next_drop[0] = pi0;
 	  to_next_drop += 1;
 	  n_left_to_next_drop -= 1;

 	  adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
 	  adj0 = adj_get (adj_index0);
 	  sw_if_index0 = adj0->rewrite_header.sw_if_index;

 	  if (is_glean)
 	    {
 	      /* resolve the packet's destination */
 	      ip4_header_t *ip0 = vlib_buffer_get_current (p0);
 	      resolve0 = ip0->dst_address;
 	      src0 = adj0->sub_type.glean.rx_pfx.fp_addr.ip4;
 	    }
 	  else
 	    {
 	      /* resolve the incomplete adj */
 	      resolve0 = adj0->sub_type.nbr.next_hop.ip4;
 	      /* Src IP address in ARP header. */
 	      if (!fib_sas4_get (sw_if_index0, &resolve0, &src0))
 		{
 		  /* No source address available */
 		  p0->error = node->errors[IP4_ARP_ERROR_NO_SOURCE_ADDRESS];
 		  continue;
 		}
 	    }

 	  /* combine the address and interface for the hash key */
 	  r0 = (u64) resolve0.data_u32 << 32;
 	  r0 |= sw_if_index0;

 	  if (throttle_check (&arp_throttle, thread_index, r0, seed))
 	    {
 	      p0->error = node->errors[IP4_ARP_ERROR_THROTTLED];
 	      continue;
 	    }

 	  /*
 	   * the adj has been updated to a rewrite but the node the DPO that got
 	   * us here hasn't - yet. no big deal. we'll drop while we wait.
 	   */
 	  if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
 	    {
 	      p0->error = node->errors[IP4_ARP_ERROR_RESOLVED];
 	      continue;
 	    }

 	  /*
 	   * Can happen if the control-plane is programming tables
 	   * with traffic flowing; at least that's today's lame excuse.
 	   */
 	  if ((is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_GLEAN)
 	      || (!is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_ARP))
 	    {
 	      p0->error = node->errors[IP4_ARP_ERROR_NON_ARP_ADJ];
 	      continue;
 	    }

 	  /* Send ARP request. */
 	  b0 = ip4_neighbor_probe (vm, vnm, adj0, &src0, &resolve0);

 	  if (PREDICT_TRUE (NULL != b0))
 	    {
 	      /* copy the persistent fields from the original */
 	      clib_memcpy_fast (b0->opaque2, p0->opaque2,
 				sizeof (p0->opaque2));
 	      p0->error = node->errors[IP4_ARP_ERROR_REQUEST_SENT];
 	    }
 	  else
 	    {
 	      p0->error = node->errors[IP4_ARP_ERROR_NO_BUFFERS];
 	      continue;
 	    }
 	}

       vlib_put_next_frame (vm, node, IP4_ARP_NEXT_DROP, n_left_to_next_drop);
     }

   return frame->n_vectors;
 }

 VLIB_NODE_FN (ip4_arp_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
 			     vlib_frame_t * frame)
 {
   return (ip4_arp_inline (vm, node, frame, 0));
 }

 VLIB_NODE_FN (ip4_glean_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
 			       vlib_frame_t * frame)
 {
   return (ip4_arp_inline (vm, node, frame, 1));
 }

 static char *ip4_arp_error_strings[] = {
   [IP4_ARP_ERROR_THROTTLED] = "ARP requests throttled",
   [IP4_ARP_ERROR_RESOLVED] = "ARP requests resolved",
   [IP4_ARP_ERROR_NO_BUFFERS] = "ARP requests out of buffer",
   [IP4_ARP_ERROR_REQUEST_SENT] = "ARP requests sent",
   [IP4_ARP_ERROR_NON_ARP_ADJ] = "ARPs to non-ARP adjacencies",
   [IP4_ARP_ERROR_NO_SOURCE_ADDRESS] = "no source address for ARP request",
 };

 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (ip4_arp_node) =
 {
   .name = "ip4-arp",
   .vector_size = sizeof (u32),
   .format_trace = format_ip4_forward_next_trace,
   .n_errors = ARRAY_LEN (ip4_arp_error_strings),
   .error_strings = ip4_arp_error_strings,
   .n_next_nodes = IP4_ARP_N_NEXT,
   .next_nodes = {
     [IP4_ARP_NEXT_DROP] = "ip4-drop",
   },
 };

 VLIB_REGISTER_NODE (ip4_glean_node) =
 {
   .name = "ip4-glean",
   .vector_size = sizeof (u32),
   .format_trace = format_ip4_forward_next_trace,
   .n_errors = ARRAY_LEN (ip4_arp_error_strings),
   .error_strings = ip4_arp_error_strings,
   .n_next_nodes = IP4_ARP_N_NEXT,
   .next_nodes = {
     [IP4_ARP_NEXT_DROP] = "ip4-drop",
   },
 };
 /* *INDENT-ON* */

 #define foreach_notrace_ip4_arp_error           \
 _(THROTTLED)                                    \
 _(RESOLVED)                                     \
 _(NO_BUFFERS)                                   \
 _(REQUEST_SENT)                                 \
 _(NON_ARP_ADJ)                                  \
 _(NO_SOURCE_ADDRESS)

 static clib_error_t *
 arp_notrace_init (vlib_main_t * vm)
 {
   vlib_node_runtime_t *rt = vlib_node_get_runtime (vm, ip4_arp_node.index);

   /* don't trace ARP request packets */
 #define _(a)                                    \
     vnet_pcap_drop_trace_filter_add_del         \
         (rt->errors[IP4_ARP_ERROR_##a],         \
          1 /* is_add */);
   foreach_notrace_ip4_arp_error;
 #undef _
   return 0;
 }

 VLIB_INIT_FUNCTION (arp_notrace_init);

 static clib_error_t *
 ip4_neighbor_main_loop_enter (vlib_main_t * vm)
 {
   vlib_thread_main_t *tm = &vlib_thread_main;
   u32 n_vlib_mains = tm->n_vlib_mains;

   throttle_init (&arp_throttle, n_vlib_mains, 1e-3);

   return (NULL);
 }

 VLIB_MAIN_LOOP_ENTER_FUNCTION (ip4_neighbor_main_loop_enter);


 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* 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.
	*/
	/*
	* ip/ip4_forward.c: IP v4 forwarding
	*
	* Copyright (c) 2008 Eliot Dresselhaus
	*
	* Permission is hereby granted, free of charge, to any person obtaining
	* a copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sublicense, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:
	*
	* The above copyright notice and this permission notice shall be
	* included in all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
	* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
	* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
	* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	*/

	#include <vnet/ip-neighbor/ip4_neighbor.h>
	#include <vnet/ethernet/ethernet.h>
	#include <vnet/util/throttle.h>
	#include <vnet/fib/fib_sas.h>

	/** ARP throttling */
	static throttle_t arp_throttle;

	VLIB_REGISTER_LOG_CLASS (ip4_neighbor_log, static) = {
	.class_name = "ip4",
	.subclass_name = "neighbor",
	};

	#define log_debug(fmt, ...) \
	vlib_log_debug (ip4_neighbor_log.class, fmt, __VA_ARGS__)

	void
	ip4_neighbor_probe_dst (u32 sw_if_index, const ip4_address_t * dst)
	{
	ip4_address_t src;
	adj_index_t ai;

	/* any glean will do, it's just for the rewrite */
	ai = adj_glean_get (FIB_PROTOCOL_IP4, sw_if_index, NULL);

	if (ADJ_INDEX_INVALID != ai && fib_sas4_get (sw_if_index, dst, &src))
	ip4_neighbor_probe (vlib_get_main (),
	vnet_get_main (), adj_get (ai), &src, dst);
	}

	void
	ip4_neighbor_advertise (vlib_main_t * vm,
	vnet_main_t * vnm,
	u32 sw_if_index, const ip4_address_t * addr)
	{
	vnet_hw_interface_t *hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
	ip4_main_t *i4m = &ip4_main;
	u8 *rewrite, rewrite_len;
	ip4_address_t tmp;

	if (NULL == addr)
	{
	if (fib_sas4_get (sw_if_index, NULL, &tmp))
	addr = &tmp;
	}

	if (addr)
	{
	log_debug ("Sending GARP for IP4 address %U on sw_if_idex %d",
	format_ip4_address, 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;

	mac_address_from_bytes (&h->ip4_over_ethernet[0].mac, hi->hw_address);
	mac_address_from_bytes (&h->ip4_over_ethernet[1].mac, hi->hw_address);
	h->ip4_over_ethernet[0].ip4 = addr[0];
	h->ip4_over_ethernet[1].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);
	}
	}

	always_inline uword
	ip4_arp_inline (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * frame, int is_glean)
	{
	vnet_main_t *vnm = vnet_get_main ();
	u32 from, to_next_drop;
	uword n_left_from, n_left_to_next_drop, next_index;
	u32 thread_index = vm->thread_index;
	u64 seed;

	if (node->flags & VLIB_NODE_FLAG_TRACE)
	ip4_forward_next_trace (vm, node, frame, VLIB_TX);

	seed = throttle_seed (&arp_throttle, thread_index, vlib_time_now (vm));

	from = vlib_frame_vector_args (frame);
	n_left_from = frame->n_vectors;
	next_index = node->cached_next_index;
	if (next_index == IP4_ARP_NEXT_DROP)
	next_index = IP4_ARP_N_NEXT; /* point to first interface */

	while (n_left_from > 0)
	{
	vlib_get_next_frame (vm, node, IP4_ARP_NEXT_DROP,
	to_next_drop, n_left_to_next_drop);

	while (n_left_from > 0 && n_left_to_next_drop > 0)
	{
	u32 pi0, adj_index0, sw_if_index0;
	ip4_address_t resolve0, src0;
	vlib_buffer_t p0, b0;
	ip_adjacency_t *adj0;
	u64 r0;

	pi0 = from[0];
	p0 = vlib_get_buffer (vm, pi0);

	from += 1;
	n_left_from -= 1;
	to_next_drop[0] = pi0;
	to_next_drop += 1;
	n_left_to_next_drop -= 1;

	adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
	adj0 = adj_get (adj_index0);
	sw_if_index0 = adj0->rewrite_header.sw_if_index;

	if (is_glean)
	{
	/* resolve the packet's destination */
	ip4_header_t *ip0 = vlib_buffer_get_current (p0);
	resolve0 = ip0->dst_address;
	src0 = adj0->sub_type.glean.rx_pfx.fp_addr.ip4;
	}
	else
	{
	/* resolve the incomplete adj */
	resolve0 = adj0->sub_type.nbr.next_hop.ip4;
	/* Src IP address in ARP header. */
	if (!fib_sas4_get (sw_if_index0, &resolve0, &src0))
	{
	/* No source address available */
	p0->error = node->errors[IP4_ARP_ERROR_NO_SOURCE_ADDRESS];
	continue;
	}
	}

	/* combine the address and interface for the hash key */
	r0 = (u64) resolve0.data_u32 << 32;
	r0 \|= sw_if_index0;

	if (throttle_check (&arp_throttle, thread_index, r0, seed))
	{
	p0->error = node->errors[IP4_ARP_ERROR_THROTTLED];
	continue;
	}

	/*
	* the adj has been updated to a rewrite but the node the DPO that got
	* us here hasn't - yet. no big deal. we'll drop while we wait.
	*/
	if (IP_LOOKUP_NEXT_REWRITE == adj0->lookup_next_index)
	{
	p0->error = node->errors[IP4_ARP_ERROR_RESOLVED];
	continue;
	}

	/*
	* Can happen if the control-plane is programming tables
	* with traffic flowing; at least that's today's lame excuse.
	*/
	if ((is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_GLEAN)
	\|\| (!is_glean && adj0->lookup_next_index != IP_LOOKUP_NEXT_ARP))
	{
	p0->error = node->errors[IP4_ARP_ERROR_NON_ARP_ADJ];
	continue;
	}

	/* Send ARP request. */
	b0 = ip4_neighbor_probe (vm, vnm, adj0, &src0, &resolve0);

	if (PREDICT_TRUE (NULL != b0))
	{
	/* copy the persistent fields from the original */
	clib_memcpy_fast (b0->opaque2, p0->opaque2,
	sizeof (p0->opaque2));
	p0->error = node->errors[IP4_ARP_ERROR_REQUEST_SENT];
	}
	else
	{
	p0->error = node->errors[IP4_ARP_ERROR_NO_BUFFERS];
	continue;
	}
	}

	vlib_put_next_frame (vm, node, IP4_ARP_NEXT_DROP, n_left_to_next_drop);
	}

	return frame->n_vectors;
	}

	VLIB_NODE_FN (ip4_arp_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
	vlib_frame_t * frame)
	{
	return (ip4_arp_inline (vm, node, frame, 0));
	}

	VLIB_NODE_FN (ip4_glean_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
	vlib_frame_t * frame)
	{
	return (ip4_arp_inline (vm, node, frame, 1));
	}

	static char *ip4_arp_error_strings[] = {
	[IP4_ARP_ERROR_THROTTLED] = "ARP requests throttled",
	[IP4_ARP_ERROR_RESOLVED] = "ARP requests resolved",
	[IP4_ARP_ERROR_NO_BUFFERS] = "ARP requests out of buffer",
	[IP4_ARP_ERROR_REQUEST_SENT] = "ARP requests sent",
	[IP4_ARP_ERROR_NON_ARP_ADJ] = "ARPs to non-ARP adjacencies",
	[IP4_ARP_ERROR_NO_SOURCE_ADDRESS] = "no source address for ARP request",
	};

	/* INDENT-OFF */
	VLIB_REGISTER_NODE (ip4_arp_node) =
	{
	.name = "ip4-arp",
	.vector_size = sizeof (u32),
	.format_trace = format_ip4_forward_next_trace,
	.n_errors = ARRAY_LEN (ip4_arp_error_strings),
	.error_strings = ip4_arp_error_strings,
	.n_next_nodes = IP4_ARP_N_NEXT,
	.next_nodes = {
	[IP4_ARP_NEXT_DROP] = "ip4-drop",
	},
	};

	VLIB_REGISTER_NODE (ip4_glean_node) =
	{
	.name = "ip4-glean",
	.vector_size = sizeof (u32),
	.format_trace = format_ip4_forward_next_trace,
	.n_errors = ARRAY_LEN (ip4_arp_error_strings),
	.error_strings = ip4_arp_error_strings,
	.n_next_nodes = IP4_ARP_N_NEXT,
	.next_nodes = {
	[IP4_ARP_NEXT_DROP] = "ip4-drop",
	},
	};
	/* INDENT-ON */

	#define foreach_notrace_ip4_arp_error \
	_(THROTTLED) \
	_(RESOLVED) \
	_(NO_BUFFERS) \
	_(REQUEST_SENT) \
	_(NON_ARP_ADJ) \
	_(NO_SOURCE_ADDRESS)

	static clib_error_t *
	arp_notrace_init (vlib_main_t * vm)
	{
	vlib_node_runtime_t *rt = vlib_node_get_runtime (vm, ip4_arp_node.index);

	/* don't trace ARP request packets */
	#define _(a) \
	vnet_pcap_drop_trace_filter_add_del \
	(rt->errors[IP4_ARP_ERROR_##a], \
	1 /* is_add */);
	foreach_notrace_ip4_arp_error;
	#undef _
	return 0;
	}

	VLIB_INIT_FUNCTION (arp_notrace_init);

	static clib_error_t *
	ip4_neighbor_main_loop_enter (vlib_main_t * vm)
	{
	vlib_thread_main_t *tm = &vlib_thread_main;
	u32 n_vlib_mains = tm->n_vlib_mains;

	throttle_init (&arp_throttle, n_vlib_mains, 1e-3);

	return (NULL);
	}

	VLIB_MAIN_LOOP_ENTER_FUNCTION (ip4_neighbor_main_loop_enter);


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