src/vnet/dpo/ip_null_dpo.c - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2016 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.
  */
 /**
  * @brief
  * The data-path object representing dropping the packet
  */

 #include <vnet/dpo/ip_null_dpo.h>
 #include <vnet/ip/ip.h>

 /**
  * @brief A representation of the IP_NULL DPO
  */
 typedef struct ip_null_dpo_t_
 {
     /**
      * @brief The action to take on a packet
      */
     ip_null_dpo_action_t ind_action;
     /**
      * @brief The next VLIB node
      */
     u32 ind_next_index;
     /**
      * rate limits
      */
 } ip_null_dpo_t;

 /**
  * @brief the IP_NULL dpos are shared by all routes, hence they are global.
  * As the neame implies this is only for IP, hence 2.
  */
 static ip_null_dpo_t ip_null_dpos[2 * IP_NULL_DPO_ACTION_NUM] = {
     [0] = {
 	/* proto ip4, no action */
 	.ind_action = IP_NULL_ACTION_NONE,
     },
     [1] = {
 	/* proto ip4, action send unreach */
 	.ind_action = IP_NULL_ACTION_SEND_ICMP_UNREACH,
     },
     [2] = {
 	/* proto ip4, action send unreach */
 	.ind_action = IP_NULL_ACTION_SEND_ICMP_PROHIBIT,
     },
     [3] = {
 	/* proto ip6, no action */
 	.ind_action = IP_NULL_ACTION_NONE,
     },
     [4] = {
 	/* proto ip6, action send unreach */
 	.ind_action = IP_NULL_ACTION_SEND_ICMP_UNREACH,
     },
     [5] = {
 	/* proto ip6, action send unreach */
 	.ind_action = IP_NULL_ACTION_SEND_ICMP_PROHIBIT,
     },
 };

 /**
  * @brief Action strings
  */
 const char *ip_null_action_strings[] = IP_NULL_ACTIONS;

 void
 ip_null_dpo_add_and_lock (dpo_proto_t proto,
 			  ip_null_dpo_action_t action,
 			  dpo_id_t *dpo)
 {
     int i;

     ASSERT((proto == DPO_PROTO_IP4) ||
 	   (proto == DPO_PROTO_IP6));
     ASSERT(action < IP_NULL_DPO_ACTION_NUM);

     i = (proto == DPO_PROTO_IP4 ? 0 : 1);

     dpo_set(dpo, DPO_IP_NULL, proto, (i*IP_NULL_DPO_ACTION_NUM) + action);
 }

 always_inline const ip_null_dpo_t*
 ip_null_dpo_get (index_t indi)
 {
     return (&ip_null_dpos[indi]);
 }

 ip_null_dpo_action_t
 ip_null_dpo_get_action (index_t indi)
 {
     return (ip_null_dpos[indi].ind_action);
 }

 static void
 ip_null_dpo_lock (dpo_id_t *dpo)
 {
     /*
      * not maintaining a lock count on the ip_null, they are const global and
      * never die.
      */
 }
 static void
 ip_null_dpo_unlock (dpo_id_t *dpo)
 {
 }

 static u8*
 format_ip_null_dpo (u8 *s, va_list *ap)
 {
     index_t index = va_arg(*ap, index_t);
     CLIB_UNUSED(u32 indent) = va_arg(*ap, u32);
     const ip_null_dpo_t *ind;
     dpo_proto_t proto;

     ind = ip_null_dpo_get(index);
     proto = (index < IP_NULL_DPO_ACTION_NUM ? DPO_PROTO_IP4 : DPO_PROTO_IP6);

     return (format(s, "%U-null action:%s",
 		   format_dpo_proto, proto,
 		   ip_null_action_strings[ind->ind_action]));
 }

 const static dpo_vft_t ip_null_vft = {
     .dv_lock   = ip_null_dpo_lock,
     .dv_unlock = ip_null_dpo_unlock,
     .dv_format = format_ip_null_dpo,
 };

 /**
  * @brief The per-protocol VLIB graph nodes that are assigned to a ip_null
  *        object.
  *
  * this means that these graph nodes are ones from which a ip_null is the
  * parent object in the DPO-graph.
  */
 const static char* const ip4_null_nodes[] =
 {
     "ip4-null",
     NULL,
 };
 const static char* const ip6_null_nodes[] =
 {
     "ip6-null",
     NULL,
 };

 const static char* const * const ip_null_nodes[DPO_PROTO_NUM] =
 {
     [DPO_PROTO_IP4] = ip4_null_nodes,
     [DPO_PROTO_IP6] = ip6_null_nodes,
 };

 typedef struct ip_null_dpo_trace_t_
 {
     index_t ind_index;
 } ip_null_dpo_trace_t;

 /**
  * @brief Exit nodes from a IP_NULL
  */
 typedef enum ip_null_next_t_
 {
     IP_NULL_NEXT_DROP,
     IP_NULL_NEXT_ICMP,
     IP_NULL_NEXT_NUM,
 } ip_null_next_t;

 always_inline uword
 ip_null_dpo_switch (vlib_main_t * vm,
 		    vlib_node_runtime_t * node,
 		    vlib_frame_t * frame,
 		    u8 is_ip4)
 {
     u32 n_left_from, next_index, *from, *to_next;
     static f64 time_last_seed_change = -1e100;
     static u32 hash_seeds[3];
     static uword hash_bitmap[256 / BITS (uword)];
     f64 time_now;

     from = vlib_frame_vector_args (frame);
     n_left_from = frame->n_vectors;

     time_now = vlib_time_now (vm);
     if (time_now - time_last_seed_change > 1e-1)
     {
 	uword i;
 	u32 * r = clib_random_buffer_get_data (&vm->random_buffer,
 					       sizeof (hash_seeds));
 	for (i = 0; i < ARRAY_LEN (hash_seeds); i++)
 	    hash_seeds[i] = r[i];

 	/* Mark all hash keys as been not-seen before. */
 	for (i = 0; i < ARRAY_LEN (hash_bitmap); i++)
 	    hash_bitmap[i] = 0;

 	time_last_seed_change = time_now;
     }

     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)
 	{
 	    u32 a0, b0, c0, m0, drop0;
 	    vlib_buffer_t *p0;
 	    u32 bi0, indi0, next0;
 	    const ip_null_dpo_t *ind0;
 	    uword bm0;

 	    bi0 = from[0];
 	    to_next[0] = bi0;
 	    from += 1;
 	    to_next += 1;
 	    n_left_from -= 1;
 	    n_left_to_next -= 1;

 	    p0 = vlib_get_buffer (vm, bi0);

 	    /* lookup dst + src mac */
 	    indi0 =  vnet_buffer (p0)->ip.adj_index[VLIB_TX];
 	    ind0 = ip_null_dpo_get(indi0);
 	    next0 = IP_NULL_NEXT_DROP;

 	    /*
 	     * rate limit - don't DoS the sender.
 	     */
 	    a0 = hash_seeds[0];
 	    b0 = hash_seeds[1];
 	    c0 = hash_seeds[2];

 	    if (is_ip4)
 	    {
 		ip4_header_t *ip0 = vlib_buffer_get_current (p0);

 		a0 ^= ip0->dst_address.data_u32;
 		b0 ^= ip0->src_address.data_u32;

 		hash_v3_finalize32 (a0, b0, c0);
 	    }
 	    else
 	    {
 		ip6_header_t *ip0 = vlib_buffer_get_current (p0);

 		a0 ^= ip0->dst_address.as_u32[0];
 		b0 ^= ip0->src_address.as_u32[0];
 		c0 ^= ip0->src_address.as_u32[1];

 		hash_v3_mix32 (a0, b0, c0);

 		a0 ^= ip0->dst_address.as_u32[1];
 		b0 ^= ip0->src_address.as_u32[2];
 		c0 ^= ip0->src_address.as_u32[3];

 		hash_v3_finalize32 (a0, b0, c0);
 	    }

 	    c0 &= BITS (hash_bitmap) - 1;
 	    c0 = c0 / BITS (uword);
 	    m0 = (uword) 1 << (c0 % BITS (uword));

 	    bm0 = hash_bitmap[c0];
 	    drop0 = (bm0 & m0) != 0;

 	    /* Mark it as seen. */
 	    hash_bitmap[c0] = bm0 | m0;

 	    if (PREDICT_FALSE(!drop0))
 	    {
 		if (is_ip4)
 		{
 		    /*
 		     * There's a trade-off here. This conditinal statement
 		     * versus a graph node per-condition. Given the number
 		     * expect number of packets to reach a null route is 0
 		     * we favour the run-time cost over the graph complexity
 		     */
 		    if (IP_NULL_ACTION_SEND_ICMP_UNREACH == ind0->ind_action)
 		    {
 			next0 = IP_NULL_NEXT_ICMP;
 			icmp4_error_set_vnet_buffer(
 			    p0,
 			    ICMP4_destination_unreachable,
 			    ICMP4_destination_unreachable_destination_unreachable_host,
 			    0);
 		    }
 		    else if (IP_NULL_ACTION_SEND_ICMP_PROHIBIT == ind0->ind_action)
 		    {
 			next0 = IP_NULL_NEXT_ICMP;
 			icmp4_error_set_vnet_buffer(
 			    p0,
 			    ICMP4_destination_unreachable,
 			    ICMP4_destination_unreachable_host_administratively_prohibited,
 			    0);
 		    }
 		}
 		else
 		{
 		    if (IP_NULL_ACTION_SEND_ICMP_UNREACH == ind0->ind_action)
 		    {
 			next0 = IP_NULL_NEXT_ICMP;
 			icmp6_error_set_vnet_buffer(
 			    p0,
 			    ICMP6_destination_unreachable,
 			    ICMP6_destination_unreachable_no_route_to_destination,
 			    0);
 		    }
 		    else if (IP_NULL_ACTION_SEND_ICMP_PROHIBIT == ind0->ind_action)
 		    {
 			next0 = IP_NULL_NEXT_ICMP;
 			icmp6_error_set_vnet_buffer(
 			    p0,
 			    ICMP6_destination_unreachable,
 			    ICMP6_destination_unreachable_destination_administratively_prohibited,
 			    0);
 		    }
 		}
 	    }

 	    if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
 	    {
 		ip_null_dpo_trace_t *tr = vlib_add_trace (vm, node, p0,
 							  sizeof (*tr));
 		tr->ind_index = indi0;
 	    }
 	    vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 					     n_left_to_next, bi0, next0);
 	}

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

     return frame->n_vectors;
 }

 static u8 *
 format_ip_null_dpo_trace (u8 * s, va_list * args)
 {
   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
   ip_null_dpo_trace_t *t = va_arg (*args, ip_null_dpo_trace_t *);

   s = format (s, "%U", format_ip_null_dpo, t->ind_index, 0);
   return s;
 }

 static uword
 ip4_null_dpo_switch (vlib_main_t * vm,
 		    vlib_node_runtime_t * node,
 		    vlib_frame_t * frame)
 {
     return (ip_null_dpo_switch(vm, node, frame, 1));
 }

 /**
  * @brief
  */
 VLIB_REGISTER_NODE (ip4_null_dpo_node) = {
   .function = ip4_null_dpo_switch,
   .name = "ip4-null",
   .vector_size = sizeof (u32),

   .format_trace = format_ip_null_dpo_trace,
   .n_next_nodes = IP_NULL_NEXT_NUM,
   .next_nodes = {
       [IP_NULL_NEXT_DROP] = "ip4-drop",
       [IP_NULL_NEXT_ICMP] = "ip4-icmp-error",
   },
 };

 static uword
 ip6_null_dpo_switch (vlib_main_t * vm,
 		    vlib_node_runtime_t * node,
 		    vlib_frame_t * frame)
 {
     return (ip_null_dpo_switch(vm, node, frame, 0));
 }

 /**
  * @brief
  */
 VLIB_REGISTER_NODE (ip6_null_dpo_node) = {
   .function = ip6_null_dpo_switch,
   .name = "ip6-null",
   .vector_size = sizeof (u32),

   .format_trace = format_ip_null_dpo_trace,
   .n_next_nodes = IP_NULL_NEXT_NUM,
   .next_nodes = {
       [IP_NULL_NEXT_DROP] = "ip6-drop",
       [IP_NULL_NEXT_ICMP] = "ip6-icmp-error",
   },
 };

 void
 ip_null_dpo_module_init (void)
 {
     dpo_register(DPO_IP_NULL, &ip_null_vft, ip_null_nodes);
 }
	/*
	* Copyright (c) 2016 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.
	*/
	/**
	* @brief
	* The data-path object representing dropping the packet
	*/

	#include <vnet/dpo/ip_null_dpo.h>
	#include <vnet/ip/ip.h>

	/**
	* @brief A representation of the IP_NULL DPO
	*/
	typedef struct ip_null_dpo_t_
	{
	/**
	* @brief The action to take on a packet
	*/
	ip_null_dpo_action_t ind_action;
	/**
	* @brief The next VLIB node
	*/
	u32 ind_next_index;
	/**
	* rate limits
	*/
	} ip_null_dpo_t;

	/**
	* @brief the IP_NULL dpos are shared by all routes, hence they are global.
	* As the neame implies this is only for IP, hence 2.
	*/
	static ip_null_dpo_t ip_null_dpos[2 * IP_NULL_DPO_ACTION_NUM] = {
	[0] = {
	/* proto ip4, no action */
	.ind_action = IP_NULL_ACTION_NONE,
	},
	[1] = {
	/* proto ip4, action send unreach */
	.ind_action = IP_NULL_ACTION_SEND_ICMP_UNREACH,
	},
	[2] = {
	/* proto ip4, action send unreach */
	.ind_action = IP_NULL_ACTION_SEND_ICMP_PROHIBIT,
	},
	[3] = {
	/* proto ip6, no action */
	.ind_action = IP_NULL_ACTION_NONE,
	},
	[4] = {
	/* proto ip6, action send unreach */
	.ind_action = IP_NULL_ACTION_SEND_ICMP_UNREACH,
	},
	[5] = {
	/* proto ip6, action send unreach */
	.ind_action = IP_NULL_ACTION_SEND_ICMP_PROHIBIT,
	},
	};

	/**
	* @brief Action strings
	*/
	const char *ip_null_action_strings[] = IP_NULL_ACTIONS;

	void
	ip_null_dpo_add_and_lock (dpo_proto_t proto,
	ip_null_dpo_action_t action,
	dpo_id_t *dpo)
	{
	int i;

	ASSERT((proto == DPO_PROTO_IP4) \|\|
	(proto == DPO_PROTO_IP6));
	ASSERT(action < IP_NULL_DPO_ACTION_NUM);

	i = (proto == DPO_PROTO_IP4 ? 0 : 1);

	dpo_set(dpo, DPO_IP_NULL, proto, (i*IP_NULL_DPO_ACTION_NUM) + action);
	}

	always_inline const ip_null_dpo_t*
	ip_null_dpo_get (index_t indi)
	{
	return (&ip_null_dpos[indi]);
	}

	ip_null_dpo_action_t
	ip_null_dpo_get_action (index_t indi)
	{
	return (ip_null_dpos[indi].ind_action);
	}

	static void
	ip_null_dpo_lock (dpo_id_t *dpo)
	{
	/*
	* not maintaining a lock count on the ip_null, they are const global and
	* never die.
	*/
	}
	static void
	ip_null_dpo_unlock (dpo_id_t *dpo)
	{
	}

	static u8*
	format_ip_null_dpo (u8 s, va_list ap)
	{
	index_t index = va_arg(*ap, index_t);
	CLIB_UNUSED(u32 indent) = va_arg(*ap, u32);
	const ip_null_dpo_t *ind;
	dpo_proto_t proto;

	ind = ip_null_dpo_get(index);
	proto = (index < IP_NULL_DPO_ACTION_NUM ? DPO_PROTO_IP4 : DPO_PROTO_IP6);

	return (format(s, "%U-null action:%s",
	format_dpo_proto, proto,
	ip_null_action_strings[ind->ind_action]));
	}

	const static dpo_vft_t ip_null_vft = {
	.dv_lock = ip_null_dpo_lock,
	.dv_unlock = ip_null_dpo_unlock,
	.dv_format = format_ip_null_dpo,
	};

	/**
	* @brief The per-protocol VLIB graph nodes that are assigned to a ip_null
	* object.
	*
	* this means that these graph nodes are ones from which a ip_null is the
	* parent object in the DPO-graph.
	*/
	const static char* const ip4_null_nodes[] =
	{
	"ip4-null",
	NULL,
	};
	const static char* const ip6_null_nodes[] =
	{
	"ip6-null",
	NULL,
	};

	const static char* const * const ip_null_nodes[DPO_PROTO_NUM] =
	{
	[DPO_PROTO_IP4] = ip4_null_nodes,
	[DPO_PROTO_IP6] = ip6_null_nodes,
	};

	typedef struct ip_null_dpo_trace_t_
	{
	index_t ind_index;
	} ip_null_dpo_trace_t;

	/**
	* @brief Exit nodes from a IP_NULL
	*/
	typedef enum ip_null_next_t_
	{
	IP_NULL_NEXT_DROP,
	IP_NULL_NEXT_ICMP,
	IP_NULL_NEXT_NUM,
	} ip_null_next_t;

	always_inline uword
	ip_null_dpo_switch (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * frame,
	u8 is_ip4)
	{
	u32 n_left_from, next_index, from, to_next;
	static f64 time_last_seed_change = -1e100;
	static u32 hash_seeds[3];
	static uword hash_bitmap[256 / BITS (uword)];
	f64 time_now;

	from = vlib_frame_vector_args (frame);
	n_left_from = frame->n_vectors;

	time_now = vlib_time_now (vm);
	if (time_now - time_last_seed_change > 1e-1)
	{
	uword i;
	u32 * r = clib_random_buffer_get_data (&vm->random_buffer,
	sizeof (hash_seeds));
	for (i = 0; i < ARRAY_LEN (hash_seeds); i++)
	hash_seeds[i] = r[i];

	/* Mark all hash keys as been not-seen before. */
	for (i = 0; i < ARRAY_LEN (hash_bitmap); i++)
	hash_bitmap[i] = 0;

	time_last_seed_change = time_now;
	}

	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)
	{
	u32 a0, b0, c0, m0, drop0;
	vlib_buffer_t *p0;
	u32 bi0, indi0, next0;
	const ip_null_dpo_t *ind0;
	uword bm0;

	bi0 = from[0];
	to_next[0] = bi0;
	from += 1;
	to_next += 1;
	n_left_from -= 1;
	n_left_to_next -= 1;

	p0 = vlib_get_buffer (vm, bi0);

	/* lookup dst + src mac */
	indi0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
	ind0 = ip_null_dpo_get(indi0);
	next0 = IP_NULL_NEXT_DROP;

	/*
	* rate limit - don't DoS the sender.
	*/
	a0 = hash_seeds[0];
	b0 = hash_seeds[1];
	c0 = hash_seeds[2];

	if (is_ip4)
	{
	ip4_header_t *ip0 = vlib_buffer_get_current (p0);

	a0 ^= ip0->dst_address.data_u32;
	b0 ^= ip0->src_address.data_u32;

	hash_v3_finalize32 (a0, b0, c0);
	}
	else
	{
	ip6_header_t *ip0 = vlib_buffer_get_current (p0);

	a0 ^= ip0->dst_address.as_u32[0];
	b0 ^= ip0->src_address.as_u32[0];
	c0 ^= ip0->src_address.as_u32[1];

	hash_v3_mix32 (a0, b0, c0);

	a0 ^= ip0->dst_address.as_u32[1];
	b0 ^= ip0->src_address.as_u32[2];
	c0 ^= ip0->src_address.as_u32[3];

	hash_v3_finalize32 (a0, b0, c0);
	}

	c0 &= BITS (hash_bitmap) - 1;
	c0 = c0 / BITS (uword);
	m0 = (uword) 1 << (c0 % BITS (uword));

	bm0 = hash_bitmap[c0];
	drop0 = (bm0 & m0) != 0;

	/* Mark it as seen. */
	hash_bitmap[c0] = bm0 \| m0;

	if (PREDICT_FALSE(!drop0))
	{
	if (is_ip4)
	{
	/*
	* There's a trade-off here. This conditinal statement
	* versus a graph node per-condition. Given the number
	* expect number of packets to reach a null route is 0
	* we favour the run-time cost over the graph complexity
	*/
	if (IP_NULL_ACTION_SEND_ICMP_UNREACH == ind0->ind_action)
	{
	next0 = IP_NULL_NEXT_ICMP;
	icmp4_error_set_vnet_buffer(
	p0,
	ICMP4_destination_unreachable,
	ICMP4_destination_unreachable_destination_unreachable_host,
	0);
	}
	else if (IP_NULL_ACTION_SEND_ICMP_PROHIBIT == ind0->ind_action)
	{
	next0 = IP_NULL_NEXT_ICMP;
	icmp4_error_set_vnet_buffer(
	p0,
	ICMP4_destination_unreachable,
	ICMP4_destination_unreachable_host_administratively_prohibited,
	0);
	}
	}
	else
	{
	if (IP_NULL_ACTION_SEND_ICMP_UNREACH == ind0->ind_action)
	{
	next0 = IP_NULL_NEXT_ICMP;
	icmp6_error_set_vnet_buffer(
	p0,
	ICMP6_destination_unreachable,
	ICMP6_destination_unreachable_no_route_to_destination,
	0);
	}
	else if (IP_NULL_ACTION_SEND_ICMP_PROHIBIT == ind0->ind_action)
	{
	next0 = IP_NULL_NEXT_ICMP;
	icmp6_error_set_vnet_buffer(
	p0,
	ICMP6_destination_unreachable,
	ICMP6_destination_unreachable_destination_administratively_prohibited,
	0);
	}
	}
	}

	if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
	{
	ip_null_dpo_trace_t *tr = vlib_add_trace (vm, node, p0,
	sizeof (*tr));
	tr->ind_index = indi0;
	}
	vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
	n_left_to_next, bi0, next0);
	}

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

	return frame->n_vectors;
	}

	static u8 *
	format_ip_null_dpo_trace (u8 * s, va_list * args)
	{
	CLIB_UNUSED (vlib_main_t * vm) = va_arg (args, vlib_main_t );
	CLIB_UNUSED (vlib_node_t * node) = va_arg (args, vlib_node_t );
	ip_null_dpo_trace_t t = va_arg (args, ip_null_dpo_trace_t *);

	s = format (s, "%U", format_ip_null_dpo, t->ind_index, 0);
	return s;
	}

	static uword
	ip4_null_dpo_switch (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * frame)
	{
	return (ip_null_dpo_switch(vm, node, frame, 1));
	}

	/**
	* @brief
	*/
	VLIB_REGISTER_NODE (ip4_null_dpo_node) = {
	.function = ip4_null_dpo_switch,
	.name = "ip4-null",
	.vector_size = sizeof (u32),

	.format_trace = format_ip_null_dpo_trace,
	.n_next_nodes = IP_NULL_NEXT_NUM,
	.next_nodes = {
	[IP_NULL_NEXT_DROP] = "ip4-drop",
	[IP_NULL_NEXT_ICMP] = "ip4-icmp-error",
	},
	};

	static uword
	ip6_null_dpo_switch (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * frame)
	{
	return (ip_null_dpo_switch(vm, node, frame, 0));
	}

	/**
	* @brief
	*/
	VLIB_REGISTER_NODE (ip6_null_dpo_node) = {
	.function = ip6_null_dpo_switch,
	.name = "ip6-null",
	.vector_size = sizeof (u32),

	.format_trace = format_ip_null_dpo_trace,
	.n_next_nodes = IP_NULL_NEXT_NUM,
	.next_nodes = {
	[IP_NULL_NEXT_DROP] = "ip6-drop",
	[IP_NULL_NEXT_ICMP] = "ip6-icmp-error",
	},
	};

	void
	ip_null_dpo_module_init (void)
	{
	dpo_register(DPO_IP_NULL, &ip_null_vft, ip_null_nodes);
	}