src/vnet/mpls/mpls_output.c - fdio/vpp - Gitiles

 /*
  * mpls_output.c: MPLS Adj rewrite
  *
  * Copyright (c) 2012-2014 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 <vlib/vlib.h>
 #include <vnet/pg/pg.h>
 #include <vnet/ip/ip.h>
 #include <vnet/mpls/mpls.h>

 typedef struct {
   /* Adjacency taken. */
   u32 adj_index;
   u32 flow_hash;

   /* Packet data, possibly *after* rewrite. */
   u8 packet_data[64 - 1*sizeof(u32)];
 } mpls_output_trace_t;

 static u8 *
 format_mpls_output_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 *);
   mpls_output_trace_t * t = va_arg (*args, mpls_output_trace_t *);
   vnet_main_t * vnm = vnet_get_main();
   uword indent = format_get_indent (s);

   s = format (s, "adj-idx %d : %U flow hash: 0x%08x",
               t->adj_index,
               format_ip_adjacency, t->adj_index, FORMAT_IP_ADJACENCY_NONE,
 	      t->flow_hash);
   s = format (s, "\n%U%U",
               format_white_space, indent,
               format_ip_adjacency_packet_data,
               vnm, t->adj_index,
               t->packet_data, sizeof (t->packet_data));
   return s;
 }

 static inline uword
 mpls_output_inline (vlib_main_t * vm,
                     vlib_node_runtime_t * node,
                     vlib_frame_t * from_frame,
 		    int is_midchain)
 {
   u32 n_left_from, next_index, * from, * to_next, cpu_index;
   vlib_node_runtime_t * error_node;
   u32 n_left_to_next;

   cpu_index = os_get_cpu_number();
   error_node = vlib_node_get_runtime (vm, mpls_output_node.index);
   from = vlib_frame_vector_args (from_frame);
   n_left_from = from_frame->n_vectors;
   next_index = node->cached_next_index;

   while (n_left_from > 0)
     {
       vlib_get_next_frame (vm, node, next_index,
                            to_next, n_left_to_next);

       while (n_left_from >= 4 && n_left_to_next >= 2)
         {
           ip_adjacency_t * adj0;
           mpls_unicast_header_t *hdr0;
           vlib_buffer_t * p0;
           u32 pi0, rw_len0, adj_index0, next0, error0;

           ip_adjacency_t * adj1;
           mpls_unicast_header_t *hdr1;
           vlib_buffer_t * p1;
           u32 pi1, rw_len1, adj_index1, next1, error1;

           /* Prefetch next iteration. */
           {
             vlib_buffer_t * p2, * p3;

             p2 = vlib_get_buffer (vm, from[2]);
             p3 = vlib_get_buffer (vm, from[3]);

             vlib_prefetch_buffer_header (p2, STORE);
             vlib_prefetch_buffer_header (p3, STORE);

             CLIB_PREFETCH (p2->data, sizeof (hdr0[0]), STORE);
             CLIB_PREFETCH (p3->data, sizeof (hdr1[0]), STORE);
           }

           pi0 = to_next[0] = from[0];
           pi1 = to_next[1] = from[1];

           from += 2;
           n_left_from -= 2;
           to_next += 2;
           n_left_to_next -= 2;

           p0 = vlib_get_buffer (vm, pi0);
           p1 = vlib_get_buffer (vm, pi1);

           adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
           adj_index1 = vnet_buffer (p1)->ip.adj_index[VLIB_TX];

           /* We should never rewrite a pkt using the MISS adjacency */
           ASSERT(adj_index0);
           ASSERT(adj_index1);

           adj0 = adj_get(adj_index0);
           adj1 = adj_get(adj_index1);
           hdr0 = vlib_buffer_get_current (p0);
           hdr1 = vlib_buffer_get_current (p1);

           /* Guess we are only writing on simple Ethernet header. */
           vnet_rewrite_two_headers (adj0[0], adj1[0], hdr0, hdr1,
                                    sizeof (ethernet_header_t));

           /* Update packet buffer attributes/set output interface. */
           rw_len0 = adj0[0].rewrite_header.data_bytes;
           rw_len1 = adj1[0].rewrite_header.data_bytes;

           /* Bump the adj counters for packet and bytes */
           vlib_increment_combined_counter
               (&adjacency_counters,
                cpu_index,
                adj_index0,
                1,
                vlib_buffer_length_in_chain (vm, p0) + rw_len0);
           vlib_increment_combined_counter
               (&adjacency_counters,
                cpu_index,
                adj_index1,
                1,
                vlib_buffer_length_in_chain (vm, p1) + rw_len1);

           /* Check MTU of outgoing interface. */
           if (PREDICT_TRUE(vlib_buffer_length_in_chain (vm, p0) <=
                            adj0[0].rewrite_header.max_l3_packet_bytes))
             {
               p0->current_data -= rw_len0;
               p0->current_length += rw_len0;

               vnet_buffer (p0)->sw_if_index[VLIB_TX] =
                   adj0[0].rewrite_header.sw_if_index;
               next0 = adj0[0].rewrite_header.next_index;
               error0 = IP4_ERROR_NONE;

               if (is_midchain)
                 {
                   adj0->sub_type.midchain.fixup_func(vm, adj0, p0);
                 }
             }
           else
             {
               error0 = IP4_ERROR_MTU_EXCEEDED;
               next0 = MPLS_OUTPUT_NEXT_DROP;
             }
           if (PREDICT_TRUE(vlib_buffer_length_in_chain (vm, p1) <=
                            adj1[0].rewrite_header.max_l3_packet_bytes))
             {
               p1->current_data -= rw_len1;
               p1->current_length += rw_len1;

               vnet_buffer (p1)->sw_if_index[VLIB_TX] =
                   adj1[0].rewrite_header.sw_if_index;
               next1 = adj1[0].rewrite_header.next_index;
               error1 = IP4_ERROR_NONE;

               if (is_midchain)
                 {
                   adj1->sub_type.midchain.fixup_func(vm, adj1, p1);
                 }
             }
           else
             {
               error1 = IP4_ERROR_MTU_EXCEEDED;
               next1 = MPLS_OUTPUT_NEXT_DROP;
             }

           p0->error = error_node->errors[error0];
           p1->error = error_node->errors[error1];

           if (PREDICT_FALSE(p0->flags & VLIB_BUFFER_IS_TRACED))
             {
               mpls_output_trace_t *tr = vlib_add_trace (vm, node,
                                                         p0, sizeof (*tr));
               tr->adj_index = vnet_buffer(p0)->ip.adj_index[VLIB_TX];
               tr->flow_hash = vnet_buffer(p0)->ip.flow_hash;
             }
           if (PREDICT_FALSE(p1->flags & VLIB_BUFFER_IS_TRACED))
             {
               mpls_output_trace_t *tr = vlib_add_trace (vm, node,
                                                         p1, sizeof (*tr));
               tr->adj_index = vnet_buffer(p1)->ip.adj_index[VLIB_TX];
               tr->flow_hash = vnet_buffer(p1)->ip.flow_hash;
             }

           vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
                                            to_next, n_left_to_next,
                                            pi0, pi1, next0, next1);
         }

       while (n_left_from > 0 && n_left_to_next > 0)
         {
 	  ip_adjacency_t * adj0;
           mpls_unicast_header_t *hdr0;
 	  vlib_buffer_t * p0;
 	  u32 pi0, rw_len0, adj_index0, next0, error0;

 	  pi0 = to_next[0] = from[0];

 	  p0 = vlib_get_buffer (vm, pi0);

 	  adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];

           /* We should never rewrite a pkt using the MISS adjacency */
           ASSERT(adj_index0);

 	  adj0 = adj_get(adj_index0);
       	  hdr0 = vlib_buffer_get_current (p0);

 	  /* Guess we are only writing on simple Ethernet header. */
           vnet_rewrite_one_header (adj0[0], hdr0,
                                    sizeof (ethernet_header_t));

           /* Update packet buffer attributes/set output interface. */
           rw_len0 = adj0[0].rewrite_header.data_bytes;

           vlib_increment_combined_counter
               (&adjacency_counters,
                cpu_index,
                adj_index0,
                1,
                vlib_buffer_length_in_chain (vm, p0) + rw_len0);

           /* Check MTU of outgoing interface. */
           if (PREDICT_TRUE(vlib_buffer_length_in_chain (vm, p0) <=
                            adj0[0].rewrite_header.max_l3_packet_bytes))
             {
               p0->current_data -= rw_len0;
               p0->current_length += rw_len0;

               vnet_buffer (p0)->sw_if_index[VLIB_TX] =
                   adj0[0].rewrite_header.sw_if_index;
               next0 = adj0[0].rewrite_header.next_index;
               error0 = IP4_ERROR_NONE;

 	      if (is_midchain)
 	        {
 		  adj0->sub_type.midchain.fixup_func(vm, adj0, p0);
 		}
             }
           else
             {
               error0 = IP4_ERROR_MTU_EXCEEDED;
               next0 = MPLS_OUTPUT_NEXT_DROP;
             }
 	  p0->error = error_node->errors[error0];

 	  from += 1;
 	  n_left_from -= 1;
 	  to_next += 1;
 	  n_left_to_next -= 1;

           if (PREDICT_FALSE(p0->flags & VLIB_BUFFER_IS_TRACED))
             {
               mpls_output_trace_t *tr = vlib_add_trace (vm, node,
                                                         p0, sizeof (*tr));
               tr->adj_index = vnet_buffer(p0)->ip.adj_index[VLIB_TX];
               tr->flow_hash = vnet_buffer(p0)->ip.flow_hash;
             }

 	  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_node_increment_counter (vm, mpls_output_node.index,
                                MPLS_ERROR_PKTS_ENCAP,
                                from_frame->n_vectors);

   return from_frame->n_vectors;
 }

 static char * mpls_error_strings[] = {
 #define mpls_error(n,s) s,
 #include "error.def"
 #undef mpls_error
 };

 static inline uword
 mpls_output (vlib_main_t * vm,
              vlib_node_runtime_t * node,
              vlib_frame_t * from_frame)
 {
     return (mpls_output_inline(vm, node, from_frame, /* is_midchain */ 0));
 }

 VLIB_REGISTER_NODE (mpls_output_node) = {
   .function = mpls_output,
   .name = "mpls-output",
   /* Takes a vector of packets. */
   .vector_size = sizeof (u32),
   .n_errors = MPLS_N_ERROR,
   .error_strings = mpls_error_strings,

   .n_next_nodes = MPLS_OUTPUT_N_NEXT,
   .next_nodes = {
 #define _(s,n) [MPLS_OUTPUT_NEXT_##s] = n,
     foreach_mpls_output_next
 #undef _
   },

   .format_trace = format_mpls_output_trace,
 };

 VLIB_NODE_FUNCTION_MULTIARCH (mpls_output_node, mpls_output)

 static inline uword
 mpls_midchain (vlib_main_t * vm,
                vlib_node_runtime_t * node,
                vlib_frame_t * from_frame)
 {
     return (mpls_output_inline(vm, node, from_frame, /* is_midchain */ 1));
 }

 VLIB_REGISTER_NODE (mpls_midchain_node) = {
   .function = mpls_midchain,
   .name = "mpls-midchain",
   .vector_size = sizeof (u32),

   .format_trace = format_mpls_output_trace,

   .sibling_of = "mpls-output",
 };

 VLIB_NODE_FUNCTION_MULTIARCH (mpls_midchain_node, mpls_midchain)

 /**
  * @brief Next index values from the MPLS incomplete adj node
  */
 #define foreach_mpls_adj_incomplete_next       	\
 _(DROP, "error-drop")                   \
 _(IP4,  "ip4-arp")                      \
 _(IP6,  "ip6-discover-neighbor")

 typedef enum {
 #define _(s,n) MPLS_ADJ_INCOMPLETE_NEXT_##s,
   foreach_mpls_adj_incomplete_next
 #undef _
   MPLS_ADJ_INCOMPLETE_N_NEXT,
 } mpls_adj_incomplete_next_t;

 /**
  * @brief A struct to hold tracing information for the MPLS label imposition
  * node.
  */
 typedef struct mpls_adj_incomplete_trace_t_
 {
     u32 next;
 } mpls_adj_incomplete_trace_t;


 /**
  * @brief Graph node for incomplete MPLS adjacency.
  * This node will push traffic to either the v4-arp or v6-nd node
  * based on the next-hop proto of the adj.
  * We pay a cost for this 'routing' node, but an incomplete adj is the
  * exception case.
  */
 static inline uword
 mpls_adj_incomplete (vlib_main_t * vm,
                      vlib_node_runtime_t * node,
                      vlib_frame_t * from_frame)
 {
     u32 n_left_from, next_index, * from, * to_next;

   from = vlib_frame_vector_args (from_frame);
   n_left_from = 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)
         {
           u32 pi0, next0, adj_index0;
 	  ip_adjacency_t * adj0;
 	  vlib_buffer_t * p0;

  	  pi0 = to_next[0] = from[0];
 	  p0 = vlib_get_buffer (vm, pi0);
 	  from += 1;
 	  n_left_from -= 1;
 	  to_next += 1;
 	  n_left_to_next -= 1;

           adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
           ASSERT(adj_index0);

 	  adj0 = adj_get(adj_index0);

           if (PREDICT_TRUE(FIB_PROTOCOL_IP4 == adj0->ia_nh_proto))
           {
               next0 = MPLS_ADJ_INCOMPLETE_NEXT_IP4;
           }
           else
           {
               next0 = MPLS_ADJ_INCOMPLETE_NEXT_IP6;
           }

 	  if (PREDICT_FALSE(p0->flags & VLIB_BUFFER_IS_TRACED))
 	  {
 	      mpls_adj_incomplete_trace_t *tr =
 		  vlib_add_trace (vm, node, p0, sizeof (*tr));
 	      tr->next = next0;
 	  }

 	  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);
     }

   return from_frame->n_vectors;
 }

 static u8 *
 format_mpls_adj_incomplete_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 *);
     mpls_adj_incomplete_trace_t * t;
     uword indent;

     t = va_arg (*args, mpls_adj_incomplete_trace_t *);
     indent = format_get_indent (s);

     s = format (s, "%Unext:%d",
                 format_white_space, indent,
                 t->next);
     return (s);
 }

 VLIB_REGISTER_NODE (mpls_adj_incomplete_node) = {
   .function = mpls_adj_incomplete,
   .name = "mpls-adj-incomplete",
   .format_trace = format_mpls_adj_incomplete_trace,
   /* Takes a vector of packets. */
   .vector_size = sizeof (u32),
   .n_errors = MPLS_N_ERROR,
   .error_strings = mpls_error_strings,

   .n_next_nodes = MPLS_ADJ_INCOMPLETE_N_NEXT,
   .next_nodes = {
 #define _(s,n) [MPLS_ADJ_INCOMPLETE_NEXT_##s] = n,
     foreach_mpls_adj_incomplete_next
 #undef _
   },
 };

 VLIB_NODE_FUNCTION_MULTIARCH (mpls_adj_incomplete_node,
                               mpls_adj_incomplete)
	/*
	* mpls_output.c: MPLS Adj rewrite
	*
	* Copyright (c) 2012-2014 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 <vlib/vlib.h>
	#include <vnet/pg/pg.h>
	#include <vnet/ip/ip.h>
	#include <vnet/mpls/mpls.h>

	typedef struct {
	/* Adjacency taken. */
	u32 adj_index;
	u32 flow_hash;

	/* Packet data, possibly after rewrite. */
	u8 packet_data[64 - 1*sizeof(u32)];
	} mpls_output_trace_t;

	static u8 *
	format_mpls_output_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 );
	mpls_output_trace_t * t = va_arg (args, mpls_output_trace_t );
	vnet_main_t * vnm = vnet_get_main();
	uword indent = format_get_indent (s);

	s = format (s, "adj-idx %d : %U flow hash: 0x%08x",
	t->adj_index,
	format_ip_adjacency, t->adj_index, FORMAT_IP_ADJACENCY_NONE,
	t->flow_hash);
	s = format (s, "\n%U%U",
	format_white_space, indent,
	format_ip_adjacency_packet_data,
	vnm, t->adj_index,
	t->packet_data, sizeof (t->packet_data));
	return s;
	}

	static inline uword
	mpls_output_inline (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame,
	int is_midchain)
	{
	u32 n_left_from, next_index, * from, * to_next, cpu_index;
	vlib_node_runtime_t * error_node;
	u32 n_left_to_next;

	cpu_index = os_get_cpu_number();
	error_node = vlib_node_get_runtime (vm, mpls_output_node.index);
	from = vlib_frame_vector_args (from_frame);
	n_left_from = from_frame->n_vectors;
	next_index = node->cached_next_index;

	while (n_left_from > 0)
	{
	vlib_get_next_frame (vm, node, next_index,
	to_next, n_left_to_next);

	while (n_left_from >= 4 && n_left_to_next >= 2)
	{
	ip_adjacency_t * adj0;
	mpls_unicast_header_t *hdr0;
	vlib_buffer_t * p0;
	u32 pi0, rw_len0, adj_index0, next0, error0;

	ip_adjacency_t * adj1;
	mpls_unicast_header_t *hdr1;
	vlib_buffer_t * p1;
	u32 pi1, rw_len1, adj_index1, next1, error1;

	/* Prefetch next iteration. */
	{
	vlib_buffer_t * p2, * p3;

	p2 = vlib_get_buffer (vm, from[2]);
	p3 = vlib_get_buffer (vm, from[3]);

	vlib_prefetch_buffer_header (p2, STORE);
	vlib_prefetch_buffer_header (p3, STORE);

	CLIB_PREFETCH (p2->data, sizeof (hdr0[0]), STORE);
	CLIB_PREFETCH (p3->data, sizeof (hdr1[0]), STORE);
	}

	pi0 = to_next[0] = from[0];
	pi1 = to_next[1] = from[1];

	from += 2;
	n_left_from -= 2;
	to_next += 2;
	n_left_to_next -= 2;

	p0 = vlib_get_buffer (vm, pi0);
	p1 = vlib_get_buffer (vm, pi1);

	adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
	adj_index1 = vnet_buffer (p1)->ip.adj_index[VLIB_TX];

	/* We should never rewrite a pkt using the MISS adjacency */
	ASSERT(adj_index0);
	ASSERT(adj_index1);

	adj0 = adj_get(adj_index0);
	adj1 = adj_get(adj_index1);
	hdr0 = vlib_buffer_get_current (p0);
	hdr1 = vlib_buffer_get_current (p1);

	/* Guess we are only writing on simple Ethernet header. */
	vnet_rewrite_two_headers (adj0[0], adj1[0], hdr0, hdr1,
	sizeof (ethernet_header_t));

	/* Update packet buffer attributes/set output interface. */
	rw_len0 = adj0[0].rewrite_header.data_bytes;
	rw_len1 = adj1[0].rewrite_header.data_bytes;

	/* Bump the adj counters for packet and bytes */
	vlib_increment_combined_counter
	(&adjacency_counters,
	cpu_index,
	adj_index0,
	1,
	vlib_buffer_length_in_chain (vm, p0) + rw_len0);
	vlib_increment_combined_counter
	(&adjacency_counters,
	cpu_index,
	adj_index1,
	1,
	vlib_buffer_length_in_chain (vm, p1) + rw_len1);

	/* Check MTU of outgoing interface. */
	if (PREDICT_TRUE(vlib_buffer_length_in_chain (vm, p0) <=
	adj0[0].rewrite_header.max_l3_packet_bytes))
	{
	p0->current_data -= rw_len0;
	p0->current_length += rw_len0;

	vnet_buffer (p0)->sw_if_index[VLIB_TX] =
	adj0[0].rewrite_header.sw_if_index;
	next0 = adj0[0].rewrite_header.next_index;
	error0 = IP4_ERROR_NONE;

	if (is_midchain)
	{
	adj0->sub_type.midchain.fixup_func(vm, adj0, p0);
	}
	}
	else
	{
	error0 = IP4_ERROR_MTU_EXCEEDED;
	next0 = MPLS_OUTPUT_NEXT_DROP;
	}
	if (PREDICT_TRUE(vlib_buffer_length_in_chain (vm, p1) <=
	adj1[0].rewrite_header.max_l3_packet_bytes))
	{
	p1->current_data -= rw_len1;
	p1->current_length += rw_len1;

	vnet_buffer (p1)->sw_if_index[VLIB_TX] =
	adj1[0].rewrite_header.sw_if_index;
	next1 = adj1[0].rewrite_header.next_index;
	error1 = IP4_ERROR_NONE;

	if (is_midchain)
	{
	adj1->sub_type.midchain.fixup_func(vm, adj1, p1);
	}
	}
	else
	{
	error1 = IP4_ERROR_MTU_EXCEEDED;
	next1 = MPLS_OUTPUT_NEXT_DROP;
	}

	p0->error = error_node->errors[error0];
	p1->error = error_node->errors[error1];

	if (PREDICT_FALSE(p0->flags & VLIB_BUFFER_IS_TRACED))
	{
	mpls_output_trace_t *tr = vlib_add_trace (vm, node,
	p0, sizeof (*tr));
	tr->adj_index = vnet_buffer(p0)->ip.adj_index[VLIB_TX];
	tr->flow_hash = vnet_buffer(p0)->ip.flow_hash;
	}
	if (PREDICT_FALSE(p1->flags & VLIB_BUFFER_IS_TRACED))
	{
	mpls_output_trace_t *tr = vlib_add_trace (vm, node,
	p1, sizeof (*tr));
	tr->adj_index = vnet_buffer(p1)->ip.adj_index[VLIB_TX];
	tr->flow_hash = vnet_buffer(p1)->ip.flow_hash;
	}

	vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
	to_next, n_left_to_next,
	pi0, pi1, next0, next1);
	}

	while (n_left_from > 0 && n_left_to_next > 0)
	{
	ip_adjacency_t * adj0;
	mpls_unicast_header_t *hdr0;
	vlib_buffer_t * p0;
	u32 pi0, rw_len0, adj_index0, next0, error0;

	pi0 = to_next[0] = from[0];

	p0 = vlib_get_buffer (vm, pi0);

	adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];

	/* We should never rewrite a pkt using the MISS adjacency */
	ASSERT(adj_index0);

	adj0 = adj_get(adj_index0);
	hdr0 = vlib_buffer_get_current (p0);

	/* Guess we are only writing on simple Ethernet header. */
	vnet_rewrite_one_header (adj0[0], hdr0,
	sizeof (ethernet_header_t));

	/* Update packet buffer attributes/set output interface. */
	rw_len0 = adj0[0].rewrite_header.data_bytes;

	vlib_increment_combined_counter
	(&adjacency_counters,
	cpu_index,
	adj_index0,
	1,
	vlib_buffer_length_in_chain (vm, p0) + rw_len0);

	/* Check MTU of outgoing interface. */
	if (PREDICT_TRUE(vlib_buffer_length_in_chain (vm, p0) <=
	adj0[0].rewrite_header.max_l3_packet_bytes))
	{
	p0->current_data -= rw_len0;
	p0->current_length += rw_len0;

	vnet_buffer (p0)->sw_if_index[VLIB_TX] =
	adj0[0].rewrite_header.sw_if_index;
	next0 = adj0[0].rewrite_header.next_index;
	error0 = IP4_ERROR_NONE;

	if (is_midchain)
	{
	adj0->sub_type.midchain.fixup_func(vm, adj0, p0);
	}
	}
	else
	{
	error0 = IP4_ERROR_MTU_EXCEEDED;
	next0 = MPLS_OUTPUT_NEXT_DROP;
	}
	p0->error = error_node->errors[error0];

	from += 1;
	n_left_from -= 1;
	to_next += 1;
	n_left_to_next -= 1;

	if (PREDICT_FALSE(p0->flags & VLIB_BUFFER_IS_TRACED))
	{
	mpls_output_trace_t *tr = vlib_add_trace (vm, node,
	p0, sizeof (*tr));
	tr->adj_index = vnet_buffer(p0)->ip.adj_index[VLIB_TX];
	tr->flow_hash = vnet_buffer(p0)->ip.flow_hash;
	}

	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_node_increment_counter (vm, mpls_output_node.index,
	MPLS_ERROR_PKTS_ENCAP,
	from_frame->n_vectors);

	return from_frame->n_vectors;
	}

	static char * mpls_error_strings[] = {
	#define mpls_error(n,s) s,
	#include "error.def"
	#undef mpls_error
	};

	static inline uword
	mpls_output (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame)
	{
	return (mpls_output_inline(vm, node, from_frame, /* is_midchain */ 0));
	}

	VLIB_REGISTER_NODE (mpls_output_node) = {
	.function = mpls_output,
	.name = "mpls-output",
	/* Takes a vector of packets. */
	.vector_size = sizeof (u32),
	.n_errors = MPLS_N_ERROR,
	.error_strings = mpls_error_strings,

	.n_next_nodes = MPLS_OUTPUT_N_NEXT,
	.next_nodes = {
	#define _(s,n) [MPLS_OUTPUT_NEXT_##s] = n,
	foreach_mpls_output_next
	#undef _
	},

	.format_trace = format_mpls_output_trace,
	};

	VLIB_NODE_FUNCTION_MULTIARCH (mpls_output_node, mpls_output)

	static inline uword
	mpls_midchain (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame)
	{
	return (mpls_output_inline(vm, node, from_frame, /* is_midchain */ 1));
	}

	VLIB_REGISTER_NODE (mpls_midchain_node) = {
	.function = mpls_midchain,
	.name = "mpls-midchain",
	.vector_size = sizeof (u32),

	.format_trace = format_mpls_output_trace,

	.sibling_of = "mpls-output",
	};

	VLIB_NODE_FUNCTION_MULTIARCH (mpls_midchain_node, mpls_midchain)

	/**
	* @brief Next index values from the MPLS incomplete adj node
	*/
	#define foreach_mpls_adj_incomplete_next \
	_(DROP, "error-drop") \
	_(IP4, "ip4-arp") \
	_(IP6, "ip6-discover-neighbor")

	typedef enum {
	#define _(s,n) MPLS_ADJ_INCOMPLETE_NEXT_##s,
	foreach_mpls_adj_incomplete_next
	#undef _
	MPLS_ADJ_INCOMPLETE_N_NEXT,
	} mpls_adj_incomplete_next_t;

	/**
	* @brief A struct to hold tracing information for the MPLS label imposition
	* node.
	*/
	typedef struct mpls_adj_incomplete_trace_t_
	{
	u32 next;
	} mpls_adj_incomplete_trace_t;


	/**
	* @brief Graph node for incomplete MPLS adjacency.
	* This node will push traffic to either the v4-arp or v6-nd node
	* based on the next-hop proto of the adj.
	* We pay a cost for this 'routing' node, but an incomplete adj is the
	* exception case.
	*/
	static inline uword
	mpls_adj_incomplete (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame)
	{
	u32 n_left_from, next_index, * from, * to_next;

	from = vlib_frame_vector_args (from_frame);
	n_left_from = 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)
	{
	u32 pi0, next0, adj_index0;
	ip_adjacency_t * adj0;
	vlib_buffer_t * p0;

	pi0 = to_next[0] = from[0];
	p0 = vlib_get_buffer (vm, pi0);
	from += 1;
	n_left_from -= 1;
	to_next += 1;
	n_left_to_next -= 1;

	adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
	ASSERT(adj_index0);

	adj0 = adj_get(adj_index0);

	if (PREDICT_TRUE(FIB_PROTOCOL_IP4 == adj0->ia_nh_proto))
	{
	next0 = MPLS_ADJ_INCOMPLETE_NEXT_IP4;
	}
	else
	{
	next0 = MPLS_ADJ_INCOMPLETE_NEXT_IP6;
	}

	if (PREDICT_FALSE(p0->flags & VLIB_BUFFER_IS_TRACED))
	{
	mpls_adj_incomplete_trace_t *tr =
	vlib_add_trace (vm, node, p0, sizeof (*tr));
	tr->next = next0;
	}

	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);
	}

	return from_frame->n_vectors;
	}

	static u8 *
	format_mpls_adj_incomplete_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 );
	mpls_adj_incomplete_trace_t * t;
	uword indent;

	t = va_arg (args, mpls_adj_incomplete_trace_t );
	indent = format_get_indent (s);

	s = format (s, "%Unext:%d",
	format_white_space, indent,
	t->next);
	return (s);
	}

	VLIB_REGISTER_NODE (mpls_adj_incomplete_node) = {
	.function = mpls_adj_incomplete,
	.name = "mpls-adj-incomplete",
	.format_trace = format_mpls_adj_incomplete_trace,
	/* Takes a vector of packets. */
	.vector_size = sizeof (u32),
	.n_errors = MPLS_N_ERROR,
	.error_strings = mpls_error_strings,

	.n_next_nodes = MPLS_ADJ_INCOMPLETE_N_NEXT,
	.next_nodes = {
	#define _(s,n) [MPLS_ADJ_INCOMPLETE_NEXT_##s] = n,
	foreach_mpls_adj_incomplete_next
	#undef _
	},
	};

	VLIB_NODE_FUNCTION_MULTIARCH (mpls_adj_incomplete_node,
	mpls_adj_incomplete)