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/ip/ip.h>
 #include <vnet/mpls/mpls.h>
 #include <vnet/ip/ip_frag.h>
 #include <vnet/adj/adj_dp.h>
 #include <vnet/mpls/mpls.api_enum.h>

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

 typedef enum {
   MPLS_OUTPUT_MODE,
   MPLS_OUTPUT_MIDCHAIN_MODE
 }mpls_output_mode_t;

 #define foreach_mpls_output_next        	\
 _(DROP, "error-drop")                           \
 _(FRAG, "mpls-frag")

 typedef enum {
 #define _(s,n) MPLS_OUTPUT_NEXT_##s,
   foreach_mpls_output_next
 #undef _
   MPLS_OUTPUT_N_NEXT,
 } mpls_output_next_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 *);

   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);
   return s;
 }

 static inline uword
 mpls_output_inline (vlib_main_t * vm,
                     vlib_node_runtime_t * node,
                     vlib_frame_t * from_frame,
                     mpls_output_mode_t mode)
 {
   u32 n_left_from, next_index, * from, * to_next, thread_index;
   vlib_node_runtime_t * error_node;
   u32 n_left_to_next;
   mpls_main_t *mm;

   thread_index = vlib_get_thread_index();
   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;
   mm = &mpls_main;

   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, adj_index0, next0, error0;
           word rw_len0;

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

           /* 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];

           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;
 	  vnet_buffer (p0)->mpls.save_rewrite_length = rw_len0;
 	  vnet_buffer (p1)->mpls.save_rewrite_length = rw_len1;

           /* Bump the adj counters for packet and bytes */
           vlib_increment_combined_counter
               (&adjacency_counters,
                thread_index,
                adj_index0,
                1,
                vlib_buffer_length_in_chain (vm, p0) + rw_len0);
           vlib_increment_combined_counter
               (&adjacency_counters,
                thread_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))
             {
               vlib_buffer_advance(p0, -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 (PREDICT_FALSE(adj0[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
                 vnet_feature_arc_start (mm->output_feature_arc_index,
                                         adj0[0].rewrite_header.sw_if_index,
                                         &next0, p0);
             }
           else
             {
 	      error0 = IP4_ERROR_MTU_EXCEEDED;
 	      next0 = MPLS_OUTPUT_NEXT_FRAG;
               vlib_node_increment_counter (vm, mpls_output_node.index,
                                            MPLS_ERROR_PKTS_NEED_FRAG,
                                            1);
             }
           if (PREDICT_TRUE(vlib_buffer_length_in_chain (vm, p1) <=
                            adj1[0].rewrite_header.max_l3_packet_bytes))
             {
               vlib_buffer_advance(p1, -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 (PREDICT_FALSE(adj1[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
                 vnet_feature_arc_start (mm->output_feature_arc_index,
                                         adj1[0].rewrite_header.sw_if_index,
                                         &next1, p1);
             }
           else
             {
 	      error1 = IP4_ERROR_MTU_EXCEEDED;
 	      next1 = MPLS_OUTPUT_NEXT_FRAG;
               vlib_node_increment_counter (vm, mpls_output_node.index,
                                            MPLS_ERROR_PKTS_NEED_FRAG,
                                            1);
             }
           if (mode == MPLS_OUTPUT_MIDCHAIN_MODE)
           {
 	    adj_midchain_fixup (vm, adj0, p0, VNET_LINK_MPLS);
 	    adj_midchain_fixup (vm, adj1, p1, VNET_LINK_MPLS);
 	  }

 	  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, adj_index0, next0, error0;
           word rw_len0;

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

 	  p0 = vlib_get_buffer (vm, pi0);

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

 	  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;
           vnet_buffer (p0)->mpls.save_rewrite_length = rw_len0;

           vlib_increment_combined_counter
               (&adjacency_counters,
                thread_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))
             {
               vlib_buffer_advance(p0, -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 (PREDICT_FALSE(adj0[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
                 vnet_feature_arc_start (mm->output_feature_arc_index,
                                         adj0[0].rewrite_header.sw_if_index,
                                         &next0, p0);
             }
           else
             {
 	      error0 = IP4_ERROR_MTU_EXCEEDED;
 	      next0 = MPLS_OUTPUT_NEXT_FRAG;
               vlib_node_increment_counter (vm, mpls_output_node.index,
                                            MPLS_ERROR_PKTS_NEED_FRAG,
                                            1);
             }
           if (mode == MPLS_OUTPUT_MIDCHAIN_MODE)
           {
 	    adj_midchain_fixup (vm, adj0, p0, VNET_LINK_MPLS);
 	  }

 	  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;
 }

 VLIB_NODE_FN (mpls_output_node) (vlib_main_t * vm,
              vlib_node_runtime_t * node,
              vlib_frame_t * from_frame)
 {
     return (mpls_output_inline(vm, node, from_frame, MPLS_OUTPUT_MODE));
 }

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

   .n_next_nodes = MPLS_OUTPUT_N_NEXT,
   .next_nodes = {
         [MPLS_OUTPUT_NEXT_DROP] = "mpls-drop",
         [MPLS_OUTPUT_NEXT_FRAG] = "mpls-frag",
     },
   .format_trace = format_mpls_output_trace,
 };

 VLIB_NODE_FN (mpls_midchain_node) (vlib_main_t * vm,
                vlib_node_runtime_t * node,
                vlib_frame_t * from_frame)
 {
     return (mpls_output_inline(vm, node, from_frame, MPLS_OUTPUT_MIDCHAIN_MODE));
 }

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

   .n_errors = MPLS_N_ERROR,
   .error_counters = mpls_error_counters,

   .sibling_of = "mpls-output",
   .format_trace = format_mpls_output_trace,
 };

 typedef struct mpls_frag_trace_t_
 {
     u16 pkt_size;
     u16 mtu;
 } mpls_frag_trace_t;

 typedef enum
 {
   MPLS_FRAG_NEXT_REWRITE,
   MPLS_FRAG_NEXT_REWRITE_MIDCHAIN,
   MPLS_FRAG_NEXT_ICMP4_ERROR,
   MPLS_FRAG_NEXT_ICMP6_ERROR,
   MPLS_FRAG_NEXT_DROP,
   MPLS_FRAG_N_NEXT,
 } mpls_frag_next_t;

 static uword
 mpls_frag (vlib_main_t * vm,
            vlib_node_runtime_t * node,
            vlib_frame_t * frame)
 {
     u32 n_left_from, next_index, * from, * to_next, n_left_to_next, *frags;

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

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

         while (n_left_from > 0 && n_left_to_next > 0)
         {
             ip_adjacency_t * adj0;
             vlib_buffer_t * p0;
             mpls_frag_next_t next0;
             u32 pi0, adj_index0;
             ip_frag_error_t error0 = IP_FRAG_ERROR_NONE;
 	    i16 encap_size, mtu;
 	    u8 is_ip4;

 	    pi0 = to_next[0] = from[0];
 	    p0 = vlib_get_buffer (vm, pi0);
 	    from += 1;
 	    n_left_from -= 1;
 	    is_ip4 = vnet_buffer (p0)->mpls.pyld_proto == DPO_PROTO_IP4;

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

 	    /* the size of the MPLS stack */
 	    encap_size = vnet_buffer (p0)->l3_hdr_offset - p0->current_data;
 	    mtu = adj0->rewrite_header.max_l3_packet_bytes - encap_size;

 	    /* IP fragmentation */
 	    if (is_ip4)
 	      error0 = ip4_frag_do_fragment (vm, pi0, mtu, encap_size, &frags);
 	    else
 	      {
 		if (!(p0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED))
 		  {
 		    /* only fragment locally generated IPv6 */
 		    error0 = IP_FRAG_ERROR_DONT_FRAGMENT_SET;
 		  }
 		else
 		  {
 		    error0 =
 		      ip6_frag_do_fragment (vm, pi0, mtu, encap_size, &frags);
 		  }
 	      }

 	    if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
 	      {
 		mpls_frag_trace_t *tr =
 		  vlib_add_trace (vm, node, p0, sizeof (*tr));
 		tr->mtu = mtu;
 		tr->pkt_size = vlib_buffer_length_in_chain (vm, p0);
 	      }

 	    if (PREDICT_TRUE (error0 == IP_FRAG_ERROR_NONE))
 	      {
 		/* Free original buffer chain */
 		vlib_buffer_free_one (vm, pi0);
 		next0 = (IP_LOOKUP_NEXT_MIDCHAIN == adj0->lookup_next_index ?
 			   MPLS_FRAG_NEXT_REWRITE_MIDCHAIN :
 			   MPLS_FRAG_NEXT_REWRITE);
 	      }
 	    else
 	      {
 		vlib_error_count (vm, node->node_index, error0, 1);

 		if (error0 == IP_FRAG_ERROR_DONT_FRAGMENT_SET)
 		  {
 		    vlib_buffer_advance (p0, encap_size);
 		    if (is_ip4)
 		      {
 			icmp4_error_set_vnet_buffer (
 			  p0, ICMP4_destination_unreachable,
 			  ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set,
 			  mtu);
 			next0 = MPLS_FRAG_NEXT_ICMP4_ERROR;
 		      }
 		    else
 		      {
 			icmp6_error_set_vnet_buffer (p0, ICMP6_packet_too_big,
 						     0, mtu);
 			next0 = MPLS_FRAG_NEXT_ICMP6_ERROR;
 		      }
 		  }
 		else
 		  {
 		    next0 = MPLS_FRAG_NEXT_DROP;
 		  }

 		/* Get rid of the original buffer */
 		vec_add1 (frags, pi0);
 	      }

 	    /* Send fragments that were added in the frame */
 	    u32 *frag_from, frag_left;

 	    frag_from = frags;
 	    frag_left = vec_len (frags);

 	    while (frag_left > 0)
 	      {
 		while (frag_left > 0 && n_left_to_next > 0)
 		  {
 		    u32 i;
 		    i = to_next[0] = frag_from[0];
 		    frag_from += 1;
 		    frag_left -= 1;
 		    to_next += 1;
 		    n_left_to_next -= 1;

 		    vlib_validate_buffer_enqueue_x1 (
 		      vm, node, next_index, to_next, n_left_to_next, i, next0);
 		  }
 		vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 		vlib_get_next_frame (vm, node, next_index, to_next,
 				     n_left_to_next);
 	      }
 	    vec_reset_length (frags);
 	}
         vlib_put_next_frame (vm, node, next_index, n_left_to_next);
     }
     vec_free (frags);

     return frame->n_vectors;
 }

 static u8 *
 format_mpls_frag_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_frag_trace_t *t = va_arg (*args, mpls_frag_trace_t *);

     s = format (s, "mtu:%d pkt-size:%d", t->mtu, t->pkt_size);
   return s;
 }

 VLIB_REGISTER_NODE (mpls_frag_node) = {
   .function = mpls_frag,
   .name = "mpls-frag",
   .vector_size = sizeof (u32),
   .format_trace = format_mpls_frag_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,

   .n_errors = IP_FRAG_N_ERROR,
   .error_counters = ip_frag_error_counters,

   .n_next_nodes = MPLS_FRAG_N_NEXT,
   .next_nodes = { [MPLS_FRAG_NEXT_REWRITE] = "mpls-output",
 		  [MPLS_FRAG_NEXT_REWRITE_MIDCHAIN] = "mpls-midchain",
 		  [MPLS_FRAG_NEXT_ICMP4_ERROR] = "ip4-icmp-error",
 		  [MPLS_FRAG_NEXT_ICMP6_ERROR] = "ip6-icmp-error",
 		  [MPLS_FRAG_NEXT_DROP] = "mpls-drop" },
 };

 /*
  * @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.
  */
 VLIB_NODE_FN (mpls_adj_incomplete_node) (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];

 	  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;
     u32 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) = {
   .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_counters = mpls_error_counters,

   .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 _
   },
 };
	/*
	* 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/ip/ip.h>
	#include <vnet/mpls/mpls.h>
	#include <vnet/ip/ip_frag.h>
	#include <vnet/adj/adj_dp.h>
	#include <vnet/mpls/mpls.api_enum.h>

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

	typedef enum {
	MPLS_OUTPUT_MODE,
	MPLS_OUTPUT_MIDCHAIN_MODE
	}mpls_output_mode_t;

	#define foreach_mpls_output_next \
	_(DROP, "error-drop") \
	_(FRAG, "mpls-frag")

	typedef enum {
	#define _(s,n) MPLS_OUTPUT_NEXT_##s,
	foreach_mpls_output_next
	#undef _
	MPLS_OUTPUT_N_NEXT,
	} mpls_output_next_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 );

	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);
	return s;
	}

	static inline uword
	mpls_output_inline (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame,
	mpls_output_mode_t mode)
	{
	u32 n_left_from, next_index, * from, * to_next, thread_index;
	vlib_node_runtime_t * error_node;
	u32 n_left_to_next;
	mpls_main_t *mm;

	thread_index = vlib_get_thread_index();
	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;
	mm = &mpls_main;

	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, adj_index0, next0, error0;
	word rw_len0;

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

	/* 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];

	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;
	vnet_buffer (p0)->mpls.save_rewrite_length = rw_len0;
	vnet_buffer (p1)->mpls.save_rewrite_length = rw_len1;

	/* Bump the adj counters for packet and bytes */
	vlib_increment_combined_counter
	(&adjacency_counters,
	thread_index,
	adj_index0,
	1,
	vlib_buffer_length_in_chain (vm, p0) + rw_len0);
	vlib_increment_combined_counter
	(&adjacency_counters,
	thread_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))
	{
	vlib_buffer_advance(p0, -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 (PREDICT_FALSE(adj0[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
	vnet_feature_arc_start (mm->output_feature_arc_index,
	adj0[0].rewrite_header.sw_if_index,
	&next0, p0);
	}
	else
	{
	error0 = IP4_ERROR_MTU_EXCEEDED;
	next0 = MPLS_OUTPUT_NEXT_FRAG;
	vlib_node_increment_counter (vm, mpls_output_node.index,
	MPLS_ERROR_PKTS_NEED_FRAG,
	1);
	}
	if (PREDICT_TRUE(vlib_buffer_length_in_chain (vm, p1) <=
	adj1[0].rewrite_header.max_l3_packet_bytes))
	{
	vlib_buffer_advance(p1, -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 (PREDICT_FALSE(adj1[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
	vnet_feature_arc_start (mm->output_feature_arc_index,
	adj1[0].rewrite_header.sw_if_index,
	&next1, p1);
	}
	else
	{
	error1 = IP4_ERROR_MTU_EXCEEDED;
	next1 = MPLS_OUTPUT_NEXT_FRAG;
	vlib_node_increment_counter (vm, mpls_output_node.index,
	MPLS_ERROR_PKTS_NEED_FRAG,
	1);
	}
	if (mode == MPLS_OUTPUT_MIDCHAIN_MODE)
	{
	adj_midchain_fixup (vm, adj0, p0, VNET_LINK_MPLS);
	adj_midchain_fixup (vm, adj1, p1, VNET_LINK_MPLS);
	}

	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, adj_index0, next0, error0;
	word rw_len0;

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

	p0 = vlib_get_buffer (vm, pi0);

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

	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;
	vnet_buffer (p0)->mpls.save_rewrite_length = rw_len0;

	vlib_increment_combined_counter
	(&adjacency_counters,
	thread_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))
	{
	vlib_buffer_advance(p0, -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 (PREDICT_FALSE(adj0[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
	vnet_feature_arc_start (mm->output_feature_arc_index,
	adj0[0].rewrite_header.sw_if_index,
	&next0, p0);
	}
	else
	{
	error0 = IP4_ERROR_MTU_EXCEEDED;
	next0 = MPLS_OUTPUT_NEXT_FRAG;
	vlib_node_increment_counter (vm, mpls_output_node.index,
	MPLS_ERROR_PKTS_NEED_FRAG,
	1);
	}
	if (mode == MPLS_OUTPUT_MIDCHAIN_MODE)
	{
	adj_midchain_fixup (vm, adj0, p0, VNET_LINK_MPLS);
	}

	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;
	}

	VLIB_NODE_FN (mpls_output_node) (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame)
	{
	return (mpls_output_inline(vm, node, from_frame, MPLS_OUTPUT_MODE));
	}

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

	.n_next_nodes = MPLS_OUTPUT_N_NEXT,
	.next_nodes = {
	[MPLS_OUTPUT_NEXT_DROP] = "mpls-drop",
	[MPLS_OUTPUT_NEXT_FRAG] = "mpls-frag",
	},
	.format_trace = format_mpls_output_trace,
	};

	VLIB_NODE_FN (mpls_midchain_node) (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame)
	{
	return (mpls_output_inline(vm, node, from_frame, MPLS_OUTPUT_MIDCHAIN_MODE));
	}

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

	.n_errors = MPLS_N_ERROR,
	.error_counters = mpls_error_counters,

	.sibling_of = "mpls-output",
	.format_trace = format_mpls_output_trace,
	};

	typedef struct mpls_frag_trace_t_
	{
	u16 pkt_size;
	u16 mtu;
	} mpls_frag_trace_t;

	typedef enum
	{
	MPLS_FRAG_NEXT_REWRITE,
	MPLS_FRAG_NEXT_REWRITE_MIDCHAIN,
	MPLS_FRAG_NEXT_ICMP4_ERROR,
	MPLS_FRAG_NEXT_ICMP6_ERROR,
	MPLS_FRAG_NEXT_DROP,
	MPLS_FRAG_N_NEXT,
	} mpls_frag_next_t;

	static uword
	mpls_frag (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * frame)
	{
	u32 n_left_from, next_index, * from, * to_next, n_left_to_next, *frags;

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

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

	while (n_left_from > 0 && n_left_to_next > 0)
	{
	ip_adjacency_t * adj0;
	vlib_buffer_t * p0;
	mpls_frag_next_t next0;
	u32 pi0, adj_index0;
	ip_frag_error_t error0 = IP_FRAG_ERROR_NONE;
	i16 encap_size, mtu;
	u8 is_ip4;

	pi0 = to_next[0] = from[0];
	p0 = vlib_get_buffer (vm, pi0);
	from += 1;
	n_left_from -= 1;
	is_ip4 = vnet_buffer (p0)->mpls.pyld_proto == DPO_PROTO_IP4;

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

	/* the size of the MPLS stack */
	encap_size = vnet_buffer (p0)->l3_hdr_offset - p0->current_data;
	mtu = adj0->rewrite_header.max_l3_packet_bytes - encap_size;

	/* IP fragmentation */
	if (is_ip4)
	error0 = ip4_frag_do_fragment (vm, pi0, mtu, encap_size, &frags);
	else
	{
	if (!(p0->flags & VNET_BUFFER_F_LOCALLY_ORIGINATED))
	{
	/* only fragment locally generated IPv6 */
	error0 = IP_FRAG_ERROR_DONT_FRAGMENT_SET;
	}
	else
	{
	error0 =
	ip6_frag_do_fragment (vm, pi0, mtu, encap_size, &frags);
	}
	}

	if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
	{
	mpls_frag_trace_t *tr =
	vlib_add_trace (vm, node, p0, sizeof (*tr));
	tr->mtu = mtu;
	tr->pkt_size = vlib_buffer_length_in_chain (vm, p0);
	}

	if (PREDICT_TRUE (error0 == IP_FRAG_ERROR_NONE))
	{
	/* Free original buffer chain */
	vlib_buffer_free_one (vm, pi0);
	next0 = (IP_LOOKUP_NEXT_MIDCHAIN == adj0->lookup_next_index ?
	MPLS_FRAG_NEXT_REWRITE_MIDCHAIN :
	MPLS_FRAG_NEXT_REWRITE);
	}
	else
	{
	vlib_error_count (vm, node->node_index, error0, 1);

	if (error0 == IP_FRAG_ERROR_DONT_FRAGMENT_SET)
	{
	vlib_buffer_advance (p0, encap_size);
	if (is_ip4)
	{
	icmp4_error_set_vnet_buffer (
	p0, ICMP4_destination_unreachable,
	ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set,
	mtu);
	next0 = MPLS_FRAG_NEXT_ICMP4_ERROR;
	}
	else
	{
	icmp6_error_set_vnet_buffer (p0, ICMP6_packet_too_big,
	0, mtu);
	next0 = MPLS_FRAG_NEXT_ICMP6_ERROR;
	}
	}
	else
	{
	next0 = MPLS_FRAG_NEXT_DROP;
	}

	/* Get rid of the original buffer */
	vec_add1 (frags, pi0);
	}

	/* Send fragments that were added in the frame */
	u32 *frag_from, frag_left;

	frag_from = frags;
	frag_left = vec_len (frags);

	while (frag_left > 0)
	{
	while (frag_left > 0 && n_left_to_next > 0)
	{
	u32 i;
	i = to_next[0] = frag_from[0];
	frag_from += 1;
	frag_left -= 1;
	to_next += 1;
	n_left_to_next -= 1;

	vlib_validate_buffer_enqueue_x1 (
	vm, node, next_index, to_next, n_left_to_next, i, next0);
	}
	vlib_put_next_frame (vm, node, next_index, n_left_to_next);
	vlib_get_next_frame (vm, node, next_index, to_next,
	n_left_to_next);
	}
	vec_reset_length (frags);
	}
	vlib_put_next_frame (vm, node, next_index, n_left_to_next);
	}
	vec_free (frags);

	return frame->n_vectors;
	}

	static u8 *
	format_mpls_frag_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_frag_trace_t t = va_arg (args, mpls_frag_trace_t *);

	s = format (s, "mtu:%d pkt-size:%d", t->mtu, t->pkt_size);
	return s;
	}

	VLIB_REGISTER_NODE (mpls_frag_node) = {
	.function = mpls_frag,
	.name = "mpls-frag",
	.vector_size = sizeof (u32),
	.format_trace = format_mpls_frag_trace,
	.type = VLIB_NODE_TYPE_INTERNAL,

	.n_errors = IP_FRAG_N_ERROR,
	.error_counters = ip_frag_error_counters,

	.n_next_nodes = MPLS_FRAG_N_NEXT,
	.next_nodes = { [MPLS_FRAG_NEXT_REWRITE] = "mpls-output",
	[MPLS_FRAG_NEXT_REWRITE_MIDCHAIN] = "mpls-midchain",
	[MPLS_FRAG_NEXT_ICMP4_ERROR] = "ip4-icmp-error",
	[MPLS_FRAG_NEXT_ICMP6_ERROR] = "ip6-icmp-error",
	[MPLS_FRAG_NEXT_DROP] = "mpls-drop" },
	};

	/*
	* @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.
	*/
	VLIB_NODE_FN (mpls_adj_incomplete_node) (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];

	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;
	u32 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) = {
	.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_counters = mpls_error_counters,

	.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 _
	},
	};