src/vnet/ip/ip4_input.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_input.c: IP v4 input node
  *
  * 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/ip4_input.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/pg/pg.h>
 #include <vnet/ppp/ppp.h>
 #include <vnet/hdlc/hdlc.h>
 #include <vnet/util/throttle.h>

 typedef struct
 {
   u8 packet_data[64];
 } ip4_input_trace_t;

 static u8 *
 format_ip4_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 *);
   ip4_input_trace_t *t = va_arg (*va, ip4_input_trace_t *);

   s = format (s, "%U",
 	      format_ip4_header, t->packet_data, sizeof (t->packet_data));

   return s;
 }

 static_always_inline u32
 ip4_input_set_next (u32 sw_if_index, vlib_buffer_t * b, int arc_enabled)
 {
   ip4_main_t *im = &ip4_main;
   ip_lookup_main_t *lm = &im->lookup_main;
   u32 next;
   u8 arc;

   ip4_header_t *ip = vlib_buffer_get_current (b);

   if (PREDICT_FALSE (ip4_address_is_multicast (&ip->dst_address)))
     {
       next = IP4_INPUT_NEXT_LOOKUP_MULTICAST;
       arc = lm->mcast_feature_arc_index;
     }
   else
     {
       next = IP4_INPUT_NEXT_LOOKUP;
       arc = lm->ucast_feature_arc_index;
     }

   if (arc_enabled)
     vnet_feature_arc_start (arc, sw_if_index, &next, b);

   return next;
 }

 static_always_inline void
 ip4_input_check_sw_if_index (vlib_main_t * vm,
 			     vlib_simple_counter_main_t * cm, u32 sw_if_index,
 			     u32 * last_sw_if_index, u32 * cnt,
 			     int *arc_enabled)
 {
   ip4_main_t *im = &ip4_main;
   ip_lookup_main_t *lm = &im->lookup_main;
   u32 thread_index;
   if (*last_sw_if_index == sw_if_index)
     {
       (*cnt)++;
       return;
     }

   thread_index = vm->thread_index;
   if (*cnt)
     vlib_increment_simple_counter (cm, thread_index, *last_sw_if_index, *cnt);
   *cnt = 1;
   *last_sw_if_index = sw_if_index;

   if (vnet_have_features (lm->ucast_feature_arc_index, sw_if_index) ||
       vnet_have_features (lm->mcast_feature_arc_index, sw_if_index))
     *arc_enabled = 1;
   else
     *arc_enabled = 0;
 }

 /* Validate IP v4 packets and pass them either to forwarding code
    or drop/punt exception packets. */
 always_inline uword
 ip4_input_inline (vlib_main_t * vm,
 		  vlib_node_runtime_t * node,
 		  vlib_frame_t * frame, int verify_checksum)
 {
   vnet_main_t *vnm = vnet_get_main ();
   u32 n_left_from, *from;
   u32 thread_index = vm->thread_index;
   vlib_node_runtime_t *error_node =
     vlib_node_get_runtime (vm, ip4_input_node.index);
   vlib_simple_counter_main_t *cm;
   vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
   ip4_header_t *ip[4];
   u16 nexts[VLIB_FRAME_SIZE], *next;
   u32 sw_if_index[4];
   u32 last_sw_if_index = ~0;
   u32 cnt = 0;
   int arc_enabled = 0;

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

   if (node->flags & VLIB_NODE_FLAG_TRACE)
     vlib_trace_frame_buffers_only (vm, node, from, frame->n_vectors,
 				   /* stride */ 1,
 				   sizeof (ip4_input_trace_t));

   cm = vec_elt_at_index (vnm->interface_main.sw_if_counters,
 			 VNET_INTERFACE_COUNTER_IP4);

   vlib_get_buffers (vm, from, bufs, n_left_from);
   b = bufs;
   next = nexts;
 #if (CLIB_N_PREFETCHES >= 8)
   while (n_left_from >= 4)
     {
       u32 x = 0;

       /* Prefetch next iteration. */
       if (n_left_from >= 12)
 	{
 	  vlib_prefetch_buffer_header (b[8], LOAD);
 	  vlib_prefetch_buffer_header (b[9], LOAD);
 	  vlib_prefetch_buffer_header (b[10], LOAD);
 	  vlib_prefetch_buffer_header (b[11], LOAD);

 	  vlib_prefetch_buffer_data (b[4], LOAD);
 	  vlib_prefetch_buffer_data (b[5], LOAD);
 	  vlib_prefetch_buffer_data (b[6], LOAD);
 	  vlib_prefetch_buffer_data (b[7], LOAD);
 	}

       vnet_buffer (b[0])->ip.adj_index[VLIB_RX] = ~0;
       vnet_buffer (b[1])->ip.adj_index[VLIB_RX] = ~0;
       vnet_buffer (b[2])->ip.adj_index[VLIB_RX] = ~0;
       vnet_buffer (b[3])->ip.adj_index[VLIB_RX] = ~0;

       sw_if_index[0] = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
       sw_if_index[1] = vnet_buffer (b[1])->sw_if_index[VLIB_RX];
       sw_if_index[2] = vnet_buffer (b[2])->sw_if_index[VLIB_RX];
       sw_if_index[3] = vnet_buffer (b[3])->sw_if_index[VLIB_RX];

       x |= sw_if_index[0] ^ last_sw_if_index;
       x |= sw_if_index[1] ^ last_sw_if_index;
       x |= sw_if_index[2] ^ last_sw_if_index;
       x |= sw_if_index[3] ^ last_sw_if_index;

       if (PREDICT_TRUE (x == 0))
 	{
 	  /* we deal with 4 more packets sharing the same sw_if_index
 	     with the previous one, so we can optimize */
 	  cnt += 4;
 	  if (arc_enabled)
 	    {
 	      next[0] = ip4_input_set_next (sw_if_index[0], b[0], 1);
 	      next[1] = ip4_input_set_next (sw_if_index[1], b[1], 1);
 	      next[2] = ip4_input_set_next (sw_if_index[2], b[2], 1);
 	      next[3] = ip4_input_set_next (sw_if_index[3], b[3], 1);
 	    }
 	  else
 	    {
 	      next[0] = ip4_input_set_next (sw_if_index[0], b[0], 0);
 	      next[1] = ip4_input_set_next (sw_if_index[1], b[1], 0);
 	      next[2] = ip4_input_set_next (sw_if_index[2], b[2], 0);
 	      next[3] = ip4_input_set_next (sw_if_index[3], b[3], 0);
 	    }
 	}
       else
 	{
 	  ip4_input_check_sw_if_index (vm, cm, sw_if_index[0],
 				       &last_sw_if_index, &cnt, &arc_enabled);
 	  ip4_input_check_sw_if_index (vm, cm, sw_if_index[1],
 				       &last_sw_if_index, &cnt, &arc_enabled);
 	  ip4_input_check_sw_if_index (vm, cm, sw_if_index[2],
 				       &last_sw_if_index, &cnt, &arc_enabled);
 	  ip4_input_check_sw_if_index (vm, cm, sw_if_index[3],
 				       &last_sw_if_index, &cnt, &arc_enabled);

 	  next[0] = ip4_input_set_next (sw_if_index[0], b[0], 1);
 	  next[1] = ip4_input_set_next (sw_if_index[1], b[1], 1);
 	  next[2] = ip4_input_set_next (sw_if_index[2], b[2], 1);
 	  next[3] = ip4_input_set_next (sw_if_index[3], b[3], 1);
 	}

       ip[0] = vlib_buffer_get_current (b[0]);
       ip[1] = vlib_buffer_get_current (b[1]);
       ip[2] = vlib_buffer_get_current (b[2]);
       ip[3] = vlib_buffer_get_current (b[3]);

       ip4_input_check_x4 (vm, error_node, b, ip, next, verify_checksum);

       /* next */
       b += 4;
       next += 4;
       n_left_from -= 4;
     }
 #elif (CLIB_N_PREFETCHES >= 4)
   while (n_left_from >= 2)
     {
       u32 x = 0;
       u32 next0, next1;

       /* Prefetch next iteration. */
       if (n_left_from >= 6)
 	{
 	  vlib_prefetch_buffer_header (b[4], LOAD);
 	  vlib_prefetch_buffer_header (b[5], LOAD);

 	  vlib_prefetch_buffer_data (b[2], LOAD);
 	  vlib_prefetch_buffer_data (b[3], LOAD);
 	}

       vnet_buffer (b[0])->ip.adj_index[VLIB_RX] = ~0;
       vnet_buffer (b[1])->ip.adj_index[VLIB_RX] = ~0;

       sw_if_index[0] = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
       sw_if_index[1] = vnet_buffer (b[1])->sw_if_index[VLIB_RX];

       x |= sw_if_index[0] ^ last_sw_if_index;
       x |= sw_if_index[1] ^ last_sw_if_index;

       if (PREDICT_TRUE (x == 0))
 	{
 	  /* we deal with 2 more packets sharing the same sw_if_index
 	     with the previous one, so we can optimize */
 	  cnt += 2;
 	  if (arc_enabled)
 	    {
 	      next0 = ip4_input_set_next (sw_if_index[0], b[0], 1);
 	      next1 = ip4_input_set_next (sw_if_index[1], b[1], 1);
 	    }
 	  else
 	    {
 	      next0 = ip4_input_set_next (sw_if_index[0], b[0], 0);
 	      next1 = ip4_input_set_next (sw_if_index[1], b[1], 0);
 	    }
 	}
       else
 	{
 	  ip4_input_check_sw_if_index (vm, cm, sw_if_index[0],
 				       &last_sw_if_index, &cnt, &arc_enabled);
 	  ip4_input_check_sw_if_index (vm, cm, sw_if_index[1],
 				       &last_sw_if_index, &cnt, &arc_enabled);

 	  next0 = ip4_input_set_next (sw_if_index[0], b[0], 1);
 	  next1 = ip4_input_set_next (sw_if_index[1], b[1], 1);
 	}

       ip[0] = vlib_buffer_get_current (b[0]);
       ip[1] = vlib_buffer_get_current (b[1]);

       ip4_input_check_x2 (vm, error_node, b[0], b[1], ip[0], ip[1],
 			  &next0, &next1, verify_checksum);
       next[0] = (u16) next0;
       next[1] = (u16) next1;

       /* next */
       b += 2;
       next += 2;
       n_left_from -= 2;
     }
 #endif

   while (n_left_from)
     {
       u32 next0;
       vnet_buffer (b[0])->ip.adj_index[VLIB_RX] = ~0;
       sw_if_index[0] = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
       ip4_input_check_sw_if_index (vm, cm, sw_if_index[0], &last_sw_if_index,
 				   &cnt, &arc_enabled);
       next0 = ip4_input_set_next (sw_if_index[0], b[0], arc_enabled);
       ip[0] = vlib_buffer_get_current (b[0]);
       ip4_input_check_x1 (vm, error_node, b[0], ip[0], &next0,
 			  verify_checksum);
       next[0] = next0;

       /* next */
       b += 1;
       next += 1;
       n_left_from -= 1;
     }

   vlib_increment_simple_counter (cm, thread_index, last_sw_if_index, cnt);
   vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);
   return frame->n_vectors;
 }

 /** \brief IPv4 input node.
     @node ip4-input

     This is the IPv4 input node: validates ip4 header checksums,
     verifies ip header lengths, discards pkts with expired TTLs,
     and sends pkts to the set of ip feature nodes configured on
     the rx interface.

     @param vm vlib_main_t corresponding to the current thread
     @param node vlib_node_runtime_t
     @param frame vlib_frame_t whose contents should be dispatched

     @par Graph mechanics: buffer metadata, next index usage

     @em Uses:
     - vnet_feature_config_main_t cm corresponding to each pkt's dst address unicast /
       multicast status.
     - <code>b->current_config_index</code> corresponding to each pkt's
       rx sw_if_index.
          - This sets the per-packet graph trajectory, ensuring that
            each packet visits the per-interface features in order.

     - <code>vnet_buffer(b)->sw_if_index[VLIB_RX]</code>
         - Indicates the @c sw_if_index value of the interface that the
 	  packet was received on.

     @em Sets:
     - <code>vnet_buffer(b)->ip.adj_index[VLIB_TX]</code>
         - The lookup result adjacency index.

     <em>Next Indices:</em>
     - Dispatches pkts to the (first) feature node:
       <code> vnet_get_config_data (... &next0 ...); </code>
       or @c error-drop
 */
 VLIB_NODE_FN (ip4_input_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
 			       vlib_frame_t * frame)
 {
   return ip4_input_inline (vm, node, frame, /* verify_checksum */ 1);
 }

 VLIB_NODE_FN (ip4_input_no_checksum_node) (vlib_main_t * vm,
 					   vlib_node_runtime_t * node,
 					   vlib_frame_t * frame)
 {
   return ip4_input_inline (vm, node, frame, /* verify_checksum */ 0);
 }

 #ifndef CLIB_MARCH_VARIANT
 char *ip4_error_strings[] = {
 #define _(sym,string) string,
   foreach_ip4_error
 #undef _
 };
 #endif

 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (ip4_input_node) = {
   .name = "ip4-input",
   .vector_size = sizeof (u32),
   .protocol_hint = VLIB_NODE_PROTO_HINT_IP4,

   .n_errors = IP4_N_ERROR,
   .error_strings = ip4_error_strings,

   .n_next_nodes = IP4_INPUT_N_NEXT,
   .next_nodes = {
     [IP4_INPUT_NEXT_DROP] = "error-drop",
     [IP4_INPUT_NEXT_PUNT] = "error-punt",
     [IP4_INPUT_NEXT_OPTIONS] = "ip4-options",
     [IP4_INPUT_NEXT_LOOKUP] = "ip4-lookup",
     [IP4_INPUT_NEXT_LOOKUP_MULTICAST] = "ip4-mfib-forward-lookup",
     [IP4_INPUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
     [IP4_INPUT_NEXT_REASSEMBLY] = "ip4-full-reassembly",
   },

   .format_buffer = format_ip4_header,
   .format_trace = format_ip4_input_trace,
 };

 VLIB_REGISTER_NODE (ip4_input_no_checksum_node) = {
   .name = "ip4-input-no-checksum",
   .vector_size = sizeof (u32),

   .sibling_of = "ip4-input",
   .format_buffer = format_ip4_header,
   .format_trace = format_ip4_input_trace,
 };
 /* *INDENT-ON* */

 static clib_error_t *
 ip4_init (vlib_main_t * vm)
 {
   clib_error_t *error;

   ethernet_register_input_type (vm, ETHERNET_TYPE_IP4, ip4_input_node.index);
   ppp_register_input_protocol (vm, PPP_PROTOCOL_ip4, ip4_input_node.index);
   hdlc_register_input_protocol (vm, HDLC_PROTOCOL_ip4, ip4_input_node.index);

   {
     extern vlib_node_registration_t ip4_input_no_checksum_node;
     pg_node_t *pn;
     pn = pg_get_node (ip4_input_node.index);
     pn->unformat_edit = unformat_pg_ip4_header;
     pn = pg_get_node (ip4_input_no_checksum_node.index);
     pn->unformat_edit = unformat_pg_ip4_header;
   }

   if ((error = vlib_call_init_function (vm, ip4_cli_init)))
     return error;

   if ((error = vlib_call_init_function
        (vm, ip4_source_and_port_range_check_init)))
     return error;

   /* Set flow hash to something non-zero. */
   ip4_main.flow_hash_seed = 0xdeadbeef;

   /* Default TTL for packets we generate. */
   ip4_main.host_config.ttl = 64;

   return error;
 }

 VLIB_INIT_FUNCTION (ip4_init);

 /*
  * 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_input.c: IP v4 input node
	*
	* 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/ip4_input.h>
	#include <vnet/ethernet/ethernet.h>
	#include <vnet/pg/pg.h>
	#include <vnet/ppp/ppp.h>
	#include <vnet/hdlc/hdlc.h>
	#include <vnet/util/throttle.h>

	typedef struct
	{
	u8 packet_data[64];
	} ip4_input_trace_t;

	static u8 *
	format_ip4_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 );
	ip4_input_trace_t t = va_arg (va, ip4_input_trace_t *);

	s = format (s, "%U",
	format_ip4_header, t->packet_data, sizeof (t->packet_data));

	return s;
	}

	static_always_inline u32
	ip4_input_set_next (u32 sw_if_index, vlib_buffer_t * b, int arc_enabled)
	{
	ip4_main_t *im = &ip4_main;
	ip_lookup_main_t *lm = &im->lookup_main;
	u32 next;
	u8 arc;

	ip4_header_t *ip = vlib_buffer_get_current (b);

	if (PREDICT_FALSE (ip4_address_is_multicast (&ip->dst_address)))
	{
	next = IP4_INPUT_NEXT_LOOKUP_MULTICAST;
	arc = lm->mcast_feature_arc_index;
	}
	else
	{
	next = IP4_INPUT_NEXT_LOOKUP;
	arc = lm->ucast_feature_arc_index;
	}

	if (arc_enabled)
	vnet_feature_arc_start (arc, sw_if_index, &next, b);

	return next;
	}

	static_always_inline void
	ip4_input_check_sw_if_index (vlib_main_t * vm,
	vlib_simple_counter_main_t * cm, u32 sw_if_index,
	u32 * last_sw_if_index, u32 * cnt,
	int *arc_enabled)
	{
	ip4_main_t *im = &ip4_main;
	ip_lookup_main_t *lm = &im->lookup_main;
	u32 thread_index;
	if (*last_sw_if_index == sw_if_index)
	{
	(*cnt)++;
	return;
	}

	thread_index = vm->thread_index;
	if (*cnt)
	vlib_increment_simple_counter (cm, thread_index, last_sw_if_index, cnt);
	*cnt = 1;
	*last_sw_if_index = sw_if_index;

	if (vnet_have_features (lm->ucast_feature_arc_index, sw_if_index) \|\|
	vnet_have_features (lm->mcast_feature_arc_index, sw_if_index))
	*arc_enabled = 1;
	else
	*arc_enabled = 0;
	}

	/* Validate IP v4 packets and pass them either to forwarding code
	or drop/punt exception packets. */
	always_inline uword
	ip4_input_inline (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * frame, int verify_checksum)
	{
	vnet_main_t *vnm = vnet_get_main ();
	u32 n_left_from, *from;
	u32 thread_index = vm->thread_index;
	vlib_node_runtime_t *error_node =
	vlib_node_get_runtime (vm, ip4_input_node.index);
	vlib_simple_counter_main_t *cm;
	vlib_buffer_t bufs[VLIB_FRAME_SIZE], *b;
	ip4_header_t *ip[4];
	u16 nexts[VLIB_FRAME_SIZE], *next;
	u32 sw_if_index[4];
	u32 last_sw_if_index = ~0;
	u32 cnt = 0;
	int arc_enabled = 0;

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

	if (node->flags & VLIB_NODE_FLAG_TRACE)
	vlib_trace_frame_buffers_only (vm, node, from, frame->n_vectors,
	/* stride */ 1,
	sizeof (ip4_input_trace_t));

	cm = vec_elt_at_index (vnm->interface_main.sw_if_counters,
	VNET_INTERFACE_COUNTER_IP4);

	vlib_get_buffers (vm, from, bufs, n_left_from);
	b = bufs;
	next = nexts;
	#if (CLIB_N_PREFETCHES >= 8)
	while (n_left_from >= 4)
	{
	u32 x = 0;

	/* Prefetch next iteration. */
	if (n_left_from >= 12)
	{
	vlib_prefetch_buffer_header (b[8], LOAD);
	vlib_prefetch_buffer_header (b[9], LOAD);
	vlib_prefetch_buffer_header (b[10], LOAD);
	vlib_prefetch_buffer_header (b[11], LOAD);

	vlib_prefetch_buffer_data (b[4], LOAD);
	vlib_prefetch_buffer_data (b[5], LOAD);
	vlib_prefetch_buffer_data (b[6], LOAD);
	vlib_prefetch_buffer_data (b[7], LOAD);
	}

	vnet_buffer (b[0])->ip.adj_index[VLIB_RX] = ~0;
	vnet_buffer (b[1])->ip.adj_index[VLIB_RX] = ~0;
	vnet_buffer (b[2])->ip.adj_index[VLIB_RX] = ~0;
	vnet_buffer (b[3])->ip.adj_index[VLIB_RX] = ~0;

	sw_if_index[0] = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
	sw_if_index[1] = vnet_buffer (b[1])->sw_if_index[VLIB_RX];
	sw_if_index[2] = vnet_buffer (b[2])->sw_if_index[VLIB_RX];
	sw_if_index[3] = vnet_buffer (b[3])->sw_if_index[VLIB_RX];

	x \|= sw_if_index[0] ^ last_sw_if_index;
	x \|= sw_if_index[1] ^ last_sw_if_index;
	x \|= sw_if_index[2] ^ last_sw_if_index;
	x \|= sw_if_index[3] ^ last_sw_if_index;

	if (PREDICT_TRUE (x == 0))
	{
	/* we deal with 4 more packets sharing the same sw_if_index
	with the previous one, so we can optimize */
	cnt += 4;
	if (arc_enabled)
	{
	next[0] = ip4_input_set_next (sw_if_index[0], b[0], 1);
	next[1] = ip4_input_set_next (sw_if_index[1], b[1], 1);
	next[2] = ip4_input_set_next (sw_if_index[2], b[2], 1);
	next[3] = ip4_input_set_next (sw_if_index[3], b[3], 1);
	}
	else
	{
	next[0] = ip4_input_set_next (sw_if_index[0], b[0], 0);
	next[1] = ip4_input_set_next (sw_if_index[1], b[1], 0);
	next[2] = ip4_input_set_next (sw_if_index[2], b[2], 0);
	next[3] = ip4_input_set_next (sw_if_index[3], b[3], 0);
	}
	}
	else
	{
	ip4_input_check_sw_if_index (vm, cm, sw_if_index[0],
	&last_sw_if_index, &cnt, &arc_enabled);
	ip4_input_check_sw_if_index (vm, cm, sw_if_index[1],
	&last_sw_if_index, &cnt, &arc_enabled);
	ip4_input_check_sw_if_index (vm, cm, sw_if_index[2],
	&last_sw_if_index, &cnt, &arc_enabled);
	ip4_input_check_sw_if_index (vm, cm, sw_if_index[3],
	&last_sw_if_index, &cnt, &arc_enabled);

	next[0] = ip4_input_set_next (sw_if_index[0], b[0], 1);
	next[1] = ip4_input_set_next (sw_if_index[1], b[1], 1);
	next[2] = ip4_input_set_next (sw_if_index[2], b[2], 1);
	next[3] = ip4_input_set_next (sw_if_index[3], b[3], 1);
	}

	ip[0] = vlib_buffer_get_current (b[0]);
	ip[1] = vlib_buffer_get_current (b[1]);
	ip[2] = vlib_buffer_get_current (b[2]);
	ip[3] = vlib_buffer_get_current (b[3]);

	ip4_input_check_x4 (vm, error_node, b, ip, next, verify_checksum);

	/* next */
	b += 4;
	next += 4;
	n_left_from -= 4;
	}
	#elif (CLIB_N_PREFETCHES >= 4)
	while (n_left_from >= 2)
	{
	u32 x = 0;
	u32 next0, next1;

	/* Prefetch next iteration. */
	if (n_left_from >= 6)
	{
	vlib_prefetch_buffer_header (b[4], LOAD);
	vlib_prefetch_buffer_header (b[5], LOAD);

	vlib_prefetch_buffer_data (b[2], LOAD);
	vlib_prefetch_buffer_data (b[3], LOAD);
	}

	vnet_buffer (b[0])->ip.adj_index[VLIB_RX] = ~0;
	vnet_buffer (b[1])->ip.adj_index[VLIB_RX] = ~0;

	sw_if_index[0] = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
	sw_if_index[1] = vnet_buffer (b[1])->sw_if_index[VLIB_RX];

	x \|= sw_if_index[0] ^ last_sw_if_index;
	x \|= sw_if_index[1] ^ last_sw_if_index;

	if (PREDICT_TRUE (x == 0))
	{
	/* we deal with 2 more packets sharing the same sw_if_index
	with the previous one, so we can optimize */
	cnt += 2;
	if (arc_enabled)
	{
	next0 = ip4_input_set_next (sw_if_index[0], b[0], 1);
	next1 = ip4_input_set_next (sw_if_index[1], b[1], 1);
	}
	else
	{
	next0 = ip4_input_set_next (sw_if_index[0], b[0], 0);
	next1 = ip4_input_set_next (sw_if_index[1], b[1], 0);
	}
	}
	else
	{
	ip4_input_check_sw_if_index (vm, cm, sw_if_index[0],
	&last_sw_if_index, &cnt, &arc_enabled);
	ip4_input_check_sw_if_index (vm, cm, sw_if_index[1],
	&last_sw_if_index, &cnt, &arc_enabled);

	next0 = ip4_input_set_next (sw_if_index[0], b[0], 1);
	next1 = ip4_input_set_next (sw_if_index[1], b[1], 1);
	}

	ip[0] = vlib_buffer_get_current (b[0]);
	ip[1] = vlib_buffer_get_current (b[1]);

	ip4_input_check_x2 (vm, error_node, b[0], b[1], ip[0], ip[1],
	&next0, &next1, verify_checksum);
	next[0] = (u16) next0;
	next[1] = (u16) next1;

	/* next */
	b += 2;
	next += 2;
	n_left_from -= 2;
	}
	#endif

	while (n_left_from)
	{
	u32 next0;
	vnet_buffer (b[0])->ip.adj_index[VLIB_RX] = ~0;
	sw_if_index[0] = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
	ip4_input_check_sw_if_index (vm, cm, sw_if_index[0], &last_sw_if_index,
	&cnt, &arc_enabled);
	next0 = ip4_input_set_next (sw_if_index[0], b[0], arc_enabled);
	ip[0] = vlib_buffer_get_current (b[0]);
	ip4_input_check_x1 (vm, error_node, b[0], ip[0], &next0,
	verify_checksum);
	next[0] = next0;

	/* next */
	b += 1;
	next += 1;
	n_left_from -= 1;
	}

	vlib_increment_simple_counter (cm, thread_index, last_sw_if_index, cnt);
	vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);
	return frame->n_vectors;
	}

	/** \brief IPv4 input node.
	@node ip4-input

	This is the IPv4 input node: validates ip4 header checksums,
	verifies ip header lengths, discards pkts with expired TTLs,
	and sends pkts to the set of ip feature nodes configured on
	the rx interface.

	@param vm vlib_main_t corresponding to the current thread
	@param node vlib_node_runtime_t
	@param frame vlib_frame_t whose contents should be dispatched

	@par Graph mechanics: buffer metadata, next index usage

	@em Uses:
	- vnet_feature_config_main_t cm corresponding to each pkt's dst address unicast /
	multicast status.
	- <code>b->current_config_index</code> corresponding to each pkt's
	rx sw_if_index.
	- This sets the per-packet graph trajectory, ensuring that
	each packet visits the per-interface features in order.

	- <code>vnet_buffer(b)->sw_if_index[VLIB_RX]</code>
	- Indicates the @c sw_if_index value of the interface that the
	packet was received on.

	@em Sets:
	- <code>vnet_buffer(b)->ip.adj_index[VLIB_TX]</code>
	- The lookup result adjacency index.

	<em>Next Indices:</em>
	- Dispatches pkts to the (first) feature node:
	<code> vnet_get_config_data (... &next0 ...); </code>
	or @c error-drop
	*/
	VLIB_NODE_FN (ip4_input_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
	vlib_frame_t * frame)
	{
	return ip4_input_inline (vm, node, frame, /* verify_checksum */ 1);
	}

	VLIB_NODE_FN (ip4_input_no_checksum_node) (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * frame)
	{
	return ip4_input_inline (vm, node, frame, /* verify_checksum */ 0);
	}

	#ifndef CLIB_MARCH_VARIANT
	char *ip4_error_strings[] = {
	#define _(sym,string) string,
	foreach_ip4_error
	#undef _
	};
	#endif

	/* INDENT-OFF */
	VLIB_REGISTER_NODE (ip4_input_node) = {
	.name = "ip4-input",
	.vector_size = sizeof (u32),
	.protocol_hint = VLIB_NODE_PROTO_HINT_IP4,

	.n_errors = IP4_N_ERROR,
	.error_strings = ip4_error_strings,

	.n_next_nodes = IP4_INPUT_N_NEXT,
	.next_nodes = {
	[IP4_INPUT_NEXT_DROP] = "error-drop",
	[IP4_INPUT_NEXT_PUNT] = "error-punt",
	[IP4_INPUT_NEXT_OPTIONS] = "ip4-options",
	[IP4_INPUT_NEXT_LOOKUP] = "ip4-lookup",
	[IP4_INPUT_NEXT_LOOKUP_MULTICAST] = "ip4-mfib-forward-lookup",
	[IP4_INPUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
	[IP4_INPUT_NEXT_REASSEMBLY] = "ip4-full-reassembly",
	},

	.format_buffer = format_ip4_header,
	.format_trace = format_ip4_input_trace,
	};

	VLIB_REGISTER_NODE (ip4_input_no_checksum_node) = {
	.name = "ip4-input-no-checksum",
	.vector_size = sizeof (u32),

	.sibling_of = "ip4-input",
	.format_buffer = format_ip4_header,
	.format_trace = format_ip4_input_trace,
	};
	/* INDENT-ON */

	static clib_error_t *
	ip4_init (vlib_main_t * vm)
	{
	clib_error_t *error;

	ethernet_register_input_type (vm, ETHERNET_TYPE_IP4, ip4_input_node.index);
	ppp_register_input_protocol (vm, PPP_PROTOCOL_ip4, ip4_input_node.index);
	hdlc_register_input_protocol (vm, HDLC_PROTOCOL_ip4, ip4_input_node.index);

	{
	extern vlib_node_registration_t ip4_input_no_checksum_node;
	pg_node_t *pn;
	pn = pg_get_node (ip4_input_node.index);
	pn->unformat_edit = unformat_pg_ip4_header;
	pn = pg_get_node (ip4_input_no_checksum_node.index);
	pn->unformat_edit = unformat_pg_ip4_header;
	}

	if ((error = vlib_call_init_function (vm, ip4_cli_init)))
	return error;

	if ((error = vlib_call_init_function
	(vm, ip4_source_and_port_range_check_init)))
	return error;

	/* Set flow hash to something non-zero. */
	ip4_main.flow_hash_seed = 0xdeadbeef;

	/* Default TTL for packets we generate. */
	ip4_main.host_config.ttl = 64;

	return error;
	}

	VLIB_INIT_FUNCTION (ip4_init);

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