src/vnet/gre/node.c - fdio/vpp - Gitiles

 /*
  * node.c: gre packet processing
  *
  * Copyright (c) 2012 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/gre/gre.h>
 #include <vnet/mpls/mpls.h>
 #include <vppinfra/sparse_vec.h>

 #define foreach_gre_input_next			\
 _(PUNT, "error-punt")                           \
 _(DROP, "error-drop")                           \
 _(ETHERNET_INPUT, "ethernet-input")             \
 _(IP4_INPUT, "ip4-input")                       \
 _(IP6_INPUT, "ip6-input")			\
 _(MPLS_INPUT, "mpls-input")

 typedef enum
 {
 #define _(s,n) GRE_INPUT_NEXT_##s,
   foreach_gre_input_next
 #undef _
     GRE_INPUT_N_NEXT,
 } gre_input_next_t;

 typedef struct
 {
   u32 tunnel_id;
   u32 length;
   ip46_address_t src;
   ip46_address_t dst;
   u8 is_ipv6;
 } gre_rx_trace_t;

 static u8 *
 format_gre_rx_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 *);
   gre_rx_trace_t *t = va_arg (*args, gre_rx_trace_t *);

   s = format (s, "GRE: tunnel %d len %d src %U dst %U",
 	      t->tunnel_id, clib_net_to_host_u16 (t->length),
 	      format_ip46_address, &t->src, IP46_TYPE_ANY,
 	      format_ip46_address, &t->dst, IP46_TYPE_ANY);
   return s;
 }

 typedef struct
 {
   /* Sparse vector mapping gre protocol in network byte order
      to next index. */
   u16 *next_by_protocol;
 } gre_input_runtime_t;

 always_inline uword
 gre_input (vlib_main_t * vm,
 	   vlib_node_runtime_t * node, vlib_frame_t * from_frame, u8 is_ipv6)
 {
   gre_main_t *gm = &gre_main;
   __attribute__ ((unused)) u32 n_left_from, next_index, *from, *to_next;
   gre_tunnel_key_t cached_tunnel_key;

   u32 cached_tunnel_sw_if_index = ~0, tunnel_sw_if_index = ~0;

   u32 thread_index = vm->thread_index;
   u32 len;
   vnet_interface_main_t *im = &gm->vnet_main->interface_main;

   if (!is_ipv6)
     clib_memset (&cached_tunnel_key.gtk_v4, 0xff,
 		 sizeof (cached_tunnel_key.gtk_v4));
   else
     clib_memset (&cached_tunnel_key.gtk_v6, 0xff,
 		 sizeof (cached_tunnel_key.gtk_v6));

   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 >= 4 && n_left_to_next >= 2)
 	{
 	  u32 bi0, bi1;
 	  vlib_buffer_t *b0, *b1;
 	  gre_header_t *h0, *h1;
 	  u16 version0, version1;
 	  int verr0, verr1;
 	  u32 i0, i1, next0, next1, protocol0, protocol1;
 	  ip4_header_t *ip4_0, *ip4_1;
 	  ip6_header_t *ip6_0, *ip6_1;
 	  gre_tunnel_key_t key0, key1;

 	  /* 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, LOAD);
 	    vlib_prefetch_buffer_header (p3, LOAD);

 	    CLIB_PREFETCH (p2->data, sizeof (h0[0]), LOAD);
 	    CLIB_PREFETCH (p3->data, sizeof (h1[0]), LOAD);
 	  }

 	  bi0 = from[0];
 	  bi1 = from[1];
 	  to_next[0] = bi0;
 	  to_next[1] = bi1;
 	  from += 2;
 	  to_next += 2;
 	  n_left_to_next -= 2;
 	  n_left_from -= 2;

 	  b0 = vlib_get_buffer (vm, bi0);
 	  b1 = vlib_get_buffer (vm, bi1);

 	  if (!is_ipv6)
 	    {
 	      /* ip4_local hands us the ip header, not the gre header */
 	      ip4_0 = vlib_buffer_get_current (b0);
 	      ip4_1 = vlib_buffer_get_current (b1);

 	      vlib_buffer_advance (b0, sizeof (*ip4_0));
 	      vlib_buffer_advance (b1, sizeof (*ip4_1));
 	    }
 	  else
 	    {
 	      /* ip6_local hands us the ip header, not the gre header */
 	      ip6_0 = vlib_buffer_get_current (b0);
 	      ip6_1 = vlib_buffer_get_current (b1);

 	      vlib_buffer_advance (b0, sizeof (*ip6_0));
 	      vlib_buffer_advance (b1, sizeof (*ip6_1));
 	    }

 	  h0 = vlib_buffer_get_current (b0);
 	  h1 = vlib_buffer_get_current (b1);

 	  /* Index sparse array with network byte order. */
 	  protocol0 = h0->protocol;
 	  protocol1 = h1->protocol;
 	  sparse_vec_index2 (gm->next_by_protocol, protocol0, protocol1,
 			     &i0, &i1);
 	  next0 = vec_elt (gm->next_by_protocol, i0).next_index;
 	  next1 = vec_elt (gm->next_by_protocol, i1).next_index;
 	  u8 ttype0 = vec_elt (gm->next_by_protocol, i0).tunnel_type;
 	  u8 ttype1 = vec_elt (gm->next_by_protocol, i1).tunnel_type;

 	  b0->error =
 	    node->errors[i0 ==
 			 SPARSE_VEC_INVALID_INDEX ? GRE_ERROR_UNKNOWN_PROTOCOL
 			 : GRE_ERROR_NONE];
 	  b1->error =
 	    node->errors[i1 ==
 			 SPARSE_VEC_INVALID_INDEX ? GRE_ERROR_UNKNOWN_PROTOCOL
 			 : GRE_ERROR_NONE];

 	  version0 = clib_net_to_host_u16 (h0->flags_and_version);
 	  verr0 = version0 & GRE_VERSION_MASK;
 	  version1 = clib_net_to_host_u16 (h1->flags_and_version);
 	  verr1 = version1 & GRE_VERSION_MASK;

 	  b0->error = verr0 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION]
 	    : b0->error;
 	  next0 = verr0 ? GRE_INPUT_NEXT_DROP : next0;
 	  b1->error = verr1 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION]
 	    : b1->error;
 	  next1 = verr1 ? GRE_INPUT_NEXT_DROP : next1;


 	  /* RPF check for ip4/ip6 input */
 	  if (PREDICT_TRUE (next0 > GRE_INPUT_NEXT_DROP))
 	    {
 	      if (is_ipv6)
 		{
 		  gre_mk_key6 (&ip6_0->dst_address,
 			       &ip6_0->src_address,
 			       vnet_buffer (b0)->ip.fib_index,
 			       ttype0, 0, &key0.gtk_v6);
 		}
 	      else
 		{
 		  gre_mk_key4 (ip4_0->dst_address,
 			       ip4_0->src_address,
 			       vnet_buffer (b0)->ip.fib_index,
 			       ttype0, 0, &key0.gtk_v4);
 		}

 	      if ((!is_ipv6 && !gre_match_key4 (&cached_tunnel_key.gtk_v4,
 						&key0.gtk_v4)) ||
 		  (is_ipv6 && !gre_match_key6 (&cached_tunnel_key.gtk_v6,
 					       &key0.gtk_v6)))
 		{
 		  gre_tunnel_t *t;
 		  uword *p;

 		  if (!is_ipv6)
 		    {
 		      p = hash_get_mem (gm->tunnel_by_key4, &key0.gtk_v4);
 		    }
 		  else
 		    {
 		      p = hash_get_mem (gm->tunnel_by_key6, &key0.gtk_v6);
 		    }
 		  if (!p)
 		    {
 		      next0 = GRE_INPUT_NEXT_DROP;
 		      b0->error = node->errors[GRE_ERROR_NO_SUCH_TUNNEL];
 		      goto drop0;
 		    }
 		  t = pool_elt_at_index (gm->tunnels, p[0]);
 		  tunnel_sw_if_index = t->sw_if_index;

 		  cached_tunnel_sw_if_index = tunnel_sw_if_index;
 		  if (!is_ipv6)
 		    {
 		      cached_tunnel_key.gtk_v4 = key0.gtk_v4;
 		    }
 		  else
 		    {
 		      cached_tunnel_key.gtk_v6 = key0.gtk_v6;
 		    }
 		}
 	      else
 		{
 		  tunnel_sw_if_index = cached_tunnel_sw_if_index;
 		}
 	    }
 	  else
 	    {
 	      next0 = GRE_INPUT_NEXT_DROP;
 	      goto drop0;
 	    }
 	  len = vlib_buffer_length_in_chain (vm, b0);
 	  vlib_increment_combined_counter (im->combined_sw_if_counters
 					   + VNET_INTERFACE_COUNTER_RX,
 					   thread_index,
 					   tunnel_sw_if_index,
 					   1 /* packets */ ,
 					   len /* bytes */ );

 	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;

 	drop0:
 	  if (PREDICT_TRUE (next1 > GRE_INPUT_NEXT_DROP))
 	    {
 	      if (is_ipv6)
 		{
 		  gre_mk_key6 (&ip6_1->dst_address,
 			       &ip6_1->src_address,
 			       vnet_buffer (b1)->ip.fib_index,
 			       ttype1, 0, &key1.gtk_v6);
 		}
 	      else
 		{
 		  gre_mk_key4 (ip4_1->dst_address,
 			       ip4_1->src_address,
 			       vnet_buffer (b1)->ip.fib_index,
 			       ttype1, 0, &key1.gtk_v4);
 		}

 	      if ((!is_ipv6 && !gre_match_key4 (&cached_tunnel_key.gtk_v4,
 						&key1.gtk_v4)) ||
 		  (is_ipv6 && !gre_match_key6 (&cached_tunnel_key.gtk_v6,
 					       &key1.gtk_v6)))
 		{
 		  gre_tunnel_t *t;
 		  uword *p;

 		  if (!is_ipv6)
 		    {
 		      p = hash_get_mem (gm->tunnel_by_key4, &key1.gtk_v4);
 		    }
 		  else
 		    {
 		      p = hash_get_mem (gm->tunnel_by_key6, &key1.gtk_v6);
 		    }
 		  if (!p)
 		    {
 		      next1 = GRE_INPUT_NEXT_DROP;
 		      b1->error = node->errors[GRE_ERROR_NO_SUCH_TUNNEL];
 		      goto drop1;
 		    }
 		  t = pool_elt_at_index (gm->tunnels, p[0]);
 		  tunnel_sw_if_index = t->sw_if_index;

 		  cached_tunnel_sw_if_index = tunnel_sw_if_index;
 		  if (!is_ipv6)
 		    {
 		      cached_tunnel_key.gtk_v4 = key1.gtk_v4;
 		    }
 		  else
 		    {
 		      cached_tunnel_key.gtk_v6 = key1.gtk_v6;
 		    }
 		}
 	      else
 		{
 		  tunnel_sw_if_index = cached_tunnel_sw_if_index;
 		}
 	    }
 	  else
 	    {
 	      next1 = GRE_INPUT_NEXT_DROP;
 	      goto drop1;
 	    }
 	  len = vlib_buffer_length_in_chain (vm, b1);
 	  vlib_increment_combined_counter (im->combined_sw_if_counters
 					   + VNET_INTERFACE_COUNTER_RX,
 					   thread_index,
 					   tunnel_sw_if_index,
 					   1 /* packets */ ,
 					   len /* bytes */ );

 	  vnet_buffer (b1)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;

 	drop1:
 	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 	    {
 	      gre_rx_trace_t *tr = vlib_add_trace (vm, node,
 						   b0, sizeof (*tr));
 	      tr->tunnel_id = tunnel_sw_if_index;
 	      if (!is_ipv6)
 		{
 		  tr->length = ip4_0->length;
 		  tr->src.ip4.as_u32 = ip4_0->src_address.as_u32;
 		  tr->dst.ip4.as_u32 = ip4_0->dst_address.as_u32;
 		}
 	      else
 		{
 		  tr->length = ip6_0->payload_length;
 		  tr->src.ip6.as_u64[0] = ip6_0->src_address.as_u64[0];
 		  tr->src.ip6.as_u64[1] = ip6_0->src_address.as_u64[1];
 		  tr->dst.ip6.as_u64[0] = ip6_0->dst_address.as_u64[0];
 		  tr->dst.ip6.as_u64[1] = ip6_0->dst_address.as_u64[1];
 		}
 	    }

 	  if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
 	    {
 	      gre_rx_trace_t *tr = vlib_add_trace (vm, node,
 						   b1, sizeof (*tr));
 	      tr->tunnel_id = tunnel_sw_if_index;
 	      if (!is_ipv6)
 		{
 		  tr->length = ip4_1->length;
 		  tr->src.ip4.as_u32 = ip4_1->src_address.as_u32;
 		  tr->dst.ip4.as_u32 = ip4_1->dst_address.as_u32;
 		}
 	      else
 		{
 		  tr->length = ip6_1->payload_length;
 		  tr->src.ip6.as_u64[0] = ip6_1->src_address.as_u64[0];
 		  tr->src.ip6.as_u64[1] = ip6_1->src_address.as_u64[1];
 		  tr->dst.ip6.as_u64[0] = ip6_1->dst_address.as_u64[0];
 		  tr->dst.ip6.as_u64[1] = ip6_1->dst_address.as_u64[1];
 		}
 	    }

 	  vlib_buffer_advance (b0, sizeof (*h0));
 	  vlib_buffer_advance (b1, sizeof (*h1));

 	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
 					   to_next, n_left_to_next,
 					   bi0, bi1, next0, next1);
 	}

       while (n_left_from > 0 && n_left_to_next > 0)
 	{
 	  u32 bi0;
 	  vlib_buffer_t *b0;
 	  gre_header_t *h0;
 	  ip4_header_t *ip4_0;
 	  ip6_header_t *ip6_0;
 	  u16 version0;
 	  int verr0;
 	  u32 i0, next0;
 	  gre_tunnel_key_t key0;

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

 	  b0 = vlib_get_buffer (vm, bi0);
 	  ip4_0 = vlib_buffer_get_current (b0);
 	  ip6_0 = (void *) ip4_0;

 	  if (!is_ipv6)
 	    {
 	      vlib_buffer_advance (b0, sizeof (*ip4_0));
 	    }
 	  else
 	    {
 	      vlib_buffer_advance (b0, sizeof (*ip6_0));
 	    }

 	  h0 = vlib_buffer_get_current (b0);

 	  i0 = sparse_vec_index (gm->next_by_protocol, h0->protocol);
 	  next0 = vec_elt (gm->next_by_protocol, i0).next_index;
 	  u8 ttype0 = vec_elt (gm->next_by_protocol, i0).tunnel_type;

 	  b0->error =
 	    node->errors[i0 == SPARSE_VEC_INVALID_INDEX
 			 ? GRE_ERROR_UNKNOWN_PROTOCOL : GRE_ERROR_NONE];

 	  version0 = clib_net_to_host_u16 (h0->flags_and_version);
 	  verr0 = version0 & GRE_VERSION_MASK;
 	  b0->error = verr0 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION]
 	    : b0->error;
 	  next0 = verr0 ? GRE_INPUT_NEXT_DROP : next0;


 	  /* For IP payload we need to find source interface
 	     so we can increase counters and help forward node to
 	     pick right FIB */
 	  /* RPF check for ip4/ip6 input */
 	  if (PREDICT_TRUE (next0 > GRE_INPUT_NEXT_DROP))
 	    {
 	      if (is_ipv6)
 		{
 		  gre_mk_key6 (&ip6_0->dst_address,
 			       &ip6_0->src_address,
 			       vnet_buffer (b0)->ip.fib_index,
 			       ttype0, 0, &key0.gtk_v6);
 		}
 	      else
 		{
 		  gre_mk_key4 (ip4_0->dst_address,
 			       ip4_0->src_address,
 			       vnet_buffer (b0)->ip.fib_index,
 			       ttype0, 0, &key0.gtk_v4);
 		}

 	      if ((!is_ipv6 && !gre_match_key4 (&cached_tunnel_key.gtk_v4,
 						&key0.gtk_v4)) ||
 		  (is_ipv6 && !gre_match_key6 (&cached_tunnel_key.gtk_v6,
 					       &key0.gtk_v6)))
 		{
 		  gre_tunnel_t *t;
 		  uword *p;

 		  if (!is_ipv6)
 		    {
 		      p = hash_get_mem (gm->tunnel_by_key4, &key0.gtk_v4);
 		    }
 		  else
 		    {
 		      p = hash_get_mem (gm->tunnel_by_key6, &key0.gtk_v6);
 		    }
 		  if (!p)
 		    {
 		      next0 = GRE_INPUT_NEXT_DROP;
 		      b0->error = node->errors[GRE_ERROR_NO_SUCH_TUNNEL];
 		      goto drop;
 		    }
 		  t = pool_elt_at_index (gm->tunnels, p[0]);
 		  tunnel_sw_if_index = t->sw_if_index;

 		  cached_tunnel_sw_if_index = tunnel_sw_if_index;
 		  if (!is_ipv6)
 		    {
 		      cached_tunnel_key.gtk_v4 = key0.gtk_v4;
 		    }
 		  else
 		    {
 		      cached_tunnel_key.gtk_v6 = key0.gtk_v6;
 		    }
 		}
 	      else
 		{
 		  tunnel_sw_if_index = cached_tunnel_sw_if_index;
 		}
 	    }
 	  else
 	    {
 	      next0 = GRE_INPUT_NEXT_DROP;
 	      goto drop;
 	    }
 	  len = vlib_buffer_length_in_chain (vm, b0);
 	  vlib_increment_combined_counter (im->combined_sw_if_counters
 					   + VNET_INTERFACE_COUNTER_RX,
 					   thread_index,
 					   tunnel_sw_if_index,
 					   1 /* packets */ ,
 					   len /* bytes */ );

 	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;

 	drop:
 	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 	    {
 	      gre_rx_trace_t *tr = vlib_add_trace (vm, node,
 						   b0, sizeof (*tr));
 	      tr->tunnel_id = tunnel_sw_if_index;
 	      if (!is_ipv6)
 		{
 		  tr->length = ip4_0->length;
 		  tr->src.ip4.as_u32 = ip4_0->src_address.as_u32;
 		  tr->dst.ip4.as_u32 = ip4_0->dst_address.as_u32;
 		}
 	      else
 		{
 		  tr->length = ip6_0->payload_length;
 		  tr->src.ip6.as_u64[0] = ip6_0->src_address.as_u64[0];
 		  tr->src.ip6.as_u64[1] = ip6_0->src_address.as_u64[1];
 		  tr->dst.ip6.as_u64[0] = ip6_0->dst_address.as_u64[0];
 		  tr->dst.ip6.as_u64[1] = ip6_0->dst_address.as_u64[1];
 		}
 	    }

 	  vlib_buffer_advance (b0, sizeof (*h0));

 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 					   to_next, n_left_to_next,
 					   bi0, next0);
 	}

       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
     }
   vlib_node_increment_counter (vm,
 			       !is_ipv6 ? gre4_input_node.index :
 			       gre6_input_node.index, GRE_ERROR_PKTS_DECAP,
 			       from_frame->n_vectors);
   return from_frame->n_vectors;
 }

 VLIB_NODE_FN (gre4_input_node) (vlib_main_t * vm,
 				vlib_node_runtime_t * node,
 				vlib_frame_t * from_frame)
 {
   return gre_input (vm, node, from_frame, /* is_ip6 */ 0);
 }

 VLIB_NODE_FN (gre6_input_node) (vlib_main_t * vm,
 				vlib_node_runtime_t * node,
 				vlib_frame_t * from_frame)
 {
   return gre_input (vm, node, from_frame, /* is_ip6 */ 1);
 }

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

 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (gre4_input_node) = {
   .name = "gre4-input",
   /* Takes a vector of packets. */
   .vector_size = sizeof (u32),

   .n_errors = GRE_N_ERROR,
   .error_strings = gre_error_strings,

   .n_next_nodes = GRE_INPUT_N_NEXT,
   .next_nodes = {
 #define _(s,n) [GRE_INPUT_NEXT_##s] = n,
     foreach_gre_input_next
 #undef _
   },

   .format_buffer = format_gre_header_with_length,
   .format_trace = format_gre_rx_trace,
   .unformat_buffer = unformat_gre_header,
 };

 VLIB_REGISTER_NODE (gre6_input_node) = {
   .name = "gre6-input",
   /* Takes a vector of packets. */
   .vector_size = sizeof (u32),

   .runtime_data_bytes = sizeof (gre_input_runtime_t),

   .n_errors = GRE_N_ERROR,
   .error_strings = gre_error_strings,

   .n_next_nodes = GRE_INPUT_N_NEXT,
   .next_nodes = {
 #define _(s,n) [GRE_INPUT_NEXT_##s] = n,
     foreach_gre_input_next
 #undef _
   },

   .format_buffer = format_gre_header_with_length,
   .format_trace = format_gre_rx_trace,
   .unformat_buffer = unformat_gre_header,
 };
 /* *INDENT-ON* */

 #ifndef CLIB_MARCH_VARIANT
 void
 gre_register_input_protocol (vlib_main_t * vm,
 			     gre_protocol_t protocol, u32 node_index,
 			     gre_tunnel_type_t tunnel_type)
 {
   gre_main_t *em = &gre_main;
   gre_protocol_info_t *pi;
   next_info_t *n;
   u32 i;

   {
     clib_error_t *error = vlib_call_init_function (vm, gre_input_init);
     if (error)
       clib_error_report (error);
   }

   pi = gre_get_protocol_info (em, protocol);
   pi->node_index = node_index;
   pi->tunnel_type = tunnel_type;
   pi->next_index = vlib_node_add_next (vm, gre4_input_node.index, node_index);
   i = vlib_node_add_next (vm, gre6_input_node.index, node_index);
   ASSERT (i == pi->next_index);

   /* Setup gre protocol -> next index sparse vector mapping. */
   n = sparse_vec_validate (em->next_by_protocol,
 			   clib_host_to_net_u16 (protocol));
   n->next_index = pi->next_index;
   n->tunnel_type = tunnel_type;
 }

 static void
 gre_setup_node (vlib_main_t * vm, u32 node_index)
 {
   vlib_node_t *n = vlib_get_node (vm, node_index);
   pg_node_t *pn = pg_get_node (node_index);

   n->format_buffer = format_gre_header_with_length;
   n->unformat_buffer = unformat_gre_header;
   pn->unformat_edit = unformat_pg_gre_header;
 }

 static clib_error_t *
 gre_input_init (vlib_main_t * vm)
 {
   gre_main_t *gm = &gre_main;
   vlib_node_t *ethernet_input, *ip4_input, *ip6_input, *mpls_unicast_input;

   {
     clib_error_t *error;
     error = vlib_call_init_function (vm, gre_init);
     if (error)
       clib_error_report (error);
   }

   gre_setup_node (vm, gre4_input_node.index);
   gre_setup_node (vm, gre6_input_node.index);

   gm->next_by_protocol = sparse_vec_new
     ( /* elt bytes */ sizeof (gm->next_by_protocol[0]),
      /* bits in index */ BITS (((gre_header_t *) 0)->protocol));

   /* These could be moved to the supported protocol input node defn's */
   ethernet_input = vlib_get_node_by_name (vm, (u8 *) "ethernet-input");
   ASSERT (ethernet_input);
   ip4_input = vlib_get_node_by_name (vm, (u8 *) "ip4-input");
   ASSERT (ip4_input);
   ip6_input = vlib_get_node_by_name (vm, (u8 *) "ip6-input");
   ASSERT (ip6_input);
   mpls_unicast_input = vlib_get_node_by_name (vm, (u8 *) "mpls-input");
   ASSERT (mpls_unicast_input);

   gre_register_input_protocol (vm, GRE_PROTOCOL_teb,
 			       ethernet_input->index, GRE_TUNNEL_TYPE_TEB);

   gre_register_input_protocol (vm, GRE_PROTOCOL_ip4,
 			       ip4_input->index, GRE_TUNNEL_TYPE_L3);

   gre_register_input_protocol (vm, GRE_PROTOCOL_ip6,
 			       ip6_input->index, GRE_TUNNEL_TYPE_L3);

   gre_register_input_protocol (vm, GRE_PROTOCOL_mpls_unicast,
 			       mpls_unicast_input->index, GRE_TUNNEL_TYPE_L3);

   ip4_register_protocol (IP_PROTOCOL_GRE, gre4_input_node.index);
   ip6_register_protocol (IP_PROTOCOL_GRE, gre6_input_node.index);

   return 0;
 }

 VLIB_INIT_FUNCTION (gre_input_init);

 #endif /* CLIB_MARCH_VARIANT */
 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* node.c: gre packet processing
	*
	* Copyright (c) 2012 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/gre/gre.h>
	#include <vnet/mpls/mpls.h>
	#include <vppinfra/sparse_vec.h>

	#define foreach_gre_input_next \
	_(PUNT, "error-punt") \
	_(DROP, "error-drop") \
	_(ETHERNET_INPUT, "ethernet-input") \
	_(IP4_INPUT, "ip4-input") \
	_(IP6_INPUT, "ip6-input") \
	_(MPLS_INPUT, "mpls-input")

	typedef enum
	{
	#define _(s,n) GRE_INPUT_NEXT_##s,
	foreach_gre_input_next
	#undef _
	GRE_INPUT_N_NEXT,
	} gre_input_next_t;

	typedef struct
	{
	u32 tunnel_id;
	u32 length;
	ip46_address_t src;
	ip46_address_t dst;
	u8 is_ipv6;
	} gre_rx_trace_t;

	static u8 *
	format_gre_rx_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 );
	gre_rx_trace_t t = va_arg (args, gre_rx_trace_t *);

	s = format (s, "GRE: tunnel %d len %d src %U dst %U",
	t->tunnel_id, clib_net_to_host_u16 (t->length),
	format_ip46_address, &t->src, IP46_TYPE_ANY,
	format_ip46_address, &t->dst, IP46_TYPE_ANY);
	return s;
	}

	typedef struct
	{
	/* Sparse vector mapping gre protocol in network byte order
	to next index. */
	u16 *next_by_protocol;
	} gre_input_runtime_t;

	always_inline uword
	gre_input (vlib_main_t * vm,
	vlib_node_runtime_t * node, vlib_frame_t * from_frame, u8 is_ipv6)
	{
	gre_main_t *gm = &gre_main;
	__attribute__ ((unused)) u32 n_left_from, next_index, from, to_next;
	gre_tunnel_key_t cached_tunnel_key;

	u32 cached_tunnel_sw_if_index = ~0, tunnel_sw_if_index = ~0;

	u32 thread_index = vm->thread_index;
	u32 len;
	vnet_interface_main_t *im = &gm->vnet_main->interface_main;

	if (!is_ipv6)
	clib_memset (&cached_tunnel_key.gtk_v4, 0xff,
	sizeof (cached_tunnel_key.gtk_v4));
	else
	clib_memset (&cached_tunnel_key.gtk_v6, 0xff,
	sizeof (cached_tunnel_key.gtk_v6));

	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 >= 4 && n_left_to_next >= 2)
	{
	u32 bi0, bi1;
	vlib_buffer_t b0, b1;
	gre_header_t h0, h1;
	u16 version0, version1;
	int verr0, verr1;
	u32 i0, i1, next0, next1, protocol0, protocol1;
	ip4_header_t ip4_0, ip4_1;
	ip6_header_t ip6_0, ip6_1;
	gre_tunnel_key_t key0, key1;

	/* 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, LOAD);
	vlib_prefetch_buffer_header (p3, LOAD);

	CLIB_PREFETCH (p2->data, sizeof (h0[0]), LOAD);
	CLIB_PREFETCH (p3->data, sizeof (h1[0]), LOAD);
	}

	bi0 = from[0];
	bi1 = from[1];
	to_next[0] = bi0;
	to_next[1] = bi1;
	from += 2;
	to_next += 2;
	n_left_to_next -= 2;
	n_left_from -= 2;

	b0 = vlib_get_buffer (vm, bi0);
	b1 = vlib_get_buffer (vm, bi1);

	if (!is_ipv6)
	{
	/* ip4_local hands us the ip header, not the gre header */
	ip4_0 = vlib_buffer_get_current (b0);
	ip4_1 = vlib_buffer_get_current (b1);

	vlib_buffer_advance (b0, sizeof (*ip4_0));
	vlib_buffer_advance (b1, sizeof (*ip4_1));
	}
	else
	{
	/* ip6_local hands us the ip header, not the gre header */
	ip6_0 = vlib_buffer_get_current (b0);
	ip6_1 = vlib_buffer_get_current (b1);

	vlib_buffer_advance (b0, sizeof (*ip6_0));
	vlib_buffer_advance (b1, sizeof (*ip6_1));
	}

	h0 = vlib_buffer_get_current (b0);
	h1 = vlib_buffer_get_current (b1);

	/* Index sparse array with network byte order. */
	protocol0 = h0->protocol;
	protocol1 = h1->protocol;
	sparse_vec_index2 (gm->next_by_protocol, protocol0, protocol1,
	&i0, &i1);
	next0 = vec_elt (gm->next_by_protocol, i0).next_index;
	next1 = vec_elt (gm->next_by_protocol, i1).next_index;
	u8 ttype0 = vec_elt (gm->next_by_protocol, i0).tunnel_type;
	u8 ttype1 = vec_elt (gm->next_by_protocol, i1).tunnel_type;

	b0->error =
	node->errors[i0 ==
	SPARSE_VEC_INVALID_INDEX ? GRE_ERROR_UNKNOWN_PROTOCOL
	: GRE_ERROR_NONE];
	b1->error =
	node->errors[i1 ==
	SPARSE_VEC_INVALID_INDEX ? GRE_ERROR_UNKNOWN_PROTOCOL
	: GRE_ERROR_NONE];

	version0 = clib_net_to_host_u16 (h0->flags_and_version);
	verr0 = version0 & GRE_VERSION_MASK;
	version1 = clib_net_to_host_u16 (h1->flags_and_version);
	verr1 = version1 & GRE_VERSION_MASK;

	b0->error = verr0 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION]
	: b0->error;
	next0 = verr0 ? GRE_INPUT_NEXT_DROP : next0;
	b1->error = verr1 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION]
	: b1->error;
	next1 = verr1 ? GRE_INPUT_NEXT_DROP : next1;


	/* RPF check for ip4/ip6 input */
	if (PREDICT_TRUE (next0 > GRE_INPUT_NEXT_DROP))
	{
	if (is_ipv6)
	{
	gre_mk_key6 (&ip6_0->dst_address,
	&ip6_0->src_address,
	vnet_buffer (b0)->ip.fib_index,
	ttype0, 0, &key0.gtk_v6);
	}
	else
	{
	gre_mk_key4 (ip4_0->dst_address,
	ip4_0->src_address,
	vnet_buffer (b0)->ip.fib_index,
	ttype0, 0, &key0.gtk_v4);
	}

	if ((!is_ipv6 && !gre_match_key4 (&cached_tunnel_key.gtk_v4,
	&key0.gtk_v4)) \|\|
	(is_ipv6 && !gre_match_key6 (&cached_tunnel_key.gtk_v6,
	&key0.gtk_v6)))
	{
	gre_tunnel_t *t;
	uword *p;

	if (!is_ipv6)
	{
	p = hash_get_mem (gm->tunnel_by_key4, &key0.gtk_v4);
	}
	else
	{
	p = hash_get_mem (gm->tunnel_by_key6, &key0.gtk_v6);
	}
	if (!p)
	{
	next0 = GRE_INPUT_NEXT_DROP;
	b0->error = node->errors[GRE_ERROR_NO_SUCH_TUNNEL];
	goto drop0;
	}
	t = pool_elt_at_index (gm->tunnels, p[0]);
	tunnel_sw_if_index = t->sw_if_index;

	cached_tunnel_sw_if_index = tunnel_sw_if_index;
	if (!is_ipv6)
	{
	cached_tunnel_key.gtk_v4 = key0.gtk_v4;
	}
	else
	{
	cached_tunnel_key.gtk_v6 = key0.gtk_v6;
	}
	}
	else
	{
	tunnel_sw_if_index = cached_tunnel_sw_if_index;
	}
	}
	else
	{
	next0 = GRE_INPUT_NEXT_DROP;
	goto drop0;
	}
	len = vlib_buffer_length_in_chain (vm, b0);
	vlib_increment_combined_counter (im->combined_sw_if_counters
	+ VNET_INTERFACE_COUNTER_RX,
	thread_index,
	tunnel_sw_if_index,
	1 /* packets */ ,
	len /* bytes */ );

	vnet_buffer (b0)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;

	drop0:
	if (PREDICT_TRUE (next1 > GRE_INPUT_NEXT_DROP))
	{
	if (is_ipv6)
	{
	gre_mk_key6 (&ip6_1->dst_address,
	&ip6_1->src_address,
	vnet_buffer (b1)->ip.fib_index,
	ttype1, 0, &key1.gtk_v6);
	}
	else
	{
	gre_mk_key4 (ip4_1->dst_address,
	ip4_1->src_address,
	vnet_buffer (b1)->ip.fib_index,
	ttype1, 0, &key1.gtk_v4);
	}

	if ((!is_ipv6 && !gre_match_key4 (&cached_tunnel_key.gtk_v4,
	&key1.gtk_v4)) \|\|
	(is_ipv6 && !gre_match_key6 (&cached_tunnel_key.gtk_v6,
	&key1.gtk_v6)))
	{
	gre_tunnel_t *t;
	uword *p;

	if (!is_ipv6)
	{
	p = hash_get_mem (gm->tunnel_by_key4, &key1.gtk_v4);
	}
	else
	{
	p = hash_get_mem (gm->tunnel_by_key6, &key1.gtk_v6);
	}
	if (!p)
	{
	next1 = GRE_INPUT_NEXT_DROP;
	b1->error = node->errors[GRE_ERROR_NO_SUCH_TUNNEL];
	goto drop1;
	}
	t = pool_elt_at_index (gm->tunnels, p[0]);
	tunnel_sw_if_index = t->sw_if_index;

	cached_tunnel_sw_if_index = tunnel_sw_if_index;
	if (!is_ipv6)
	{
	cached_tunnel_key.gtk_v4 = key1.gtk_v4;
	}
	else
	{
	cached_tunnel_key.gtk_v6 = key1.gtk_v6;
	}
	}
	else
	{
	tunnel_sw_if_index = cached_tunnel_sw_if_index;
	}
	}
	else
	{
	next1 = GRE_INPUT_NEXT_DROP;
	goto drop1;
	}
	len = vlib_buffer_length_in_chain (vm, b1);
	vlib_increment_combined_counter (im->combined_sw_if_counters
	+ VNET_INTERFACE_COUNTER_RX,
	thread_index,
	tunnel_sw_if_index,
	1 /* packets */ ,
	len /* bytes */ );

	vnet_buffer (b1)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;

	drop1:
	if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	{
	gre_rx_trace_t *tr = vlib_add_trace (vm, node,
	b0, sizeof (*tr));
	tr->tunnel_id = tunnel_sw_if_index;
	if (!is_ipv6)
	{
	tr->length = ip4_0->length;
	tr->src.ip4.as_u32 = ip4_0->src_address.as_u32;
	tr->dst.ip4.as_u32 = ip4_0->dst_address.as_u32;
	}
	else
	{
	tr->length = ip6_0->payload_length;
	tr->src.ip6.as_u64[0] = ip6_0->src_address.as_u64[0];
	tr->src.ip6.as_u64[1] = ip6_0->src_address.as_u64[1];
	tr->dst.ip6.as_u64[0] = ip6_0->dst_address.as_u64[0];
	tr->dst.ip6.as_u64[1] = ip6_0->dst_address.as_u64[1];
	}
	}

	if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
	{
	gre_rx_trace_t *tr = vlib_add_trace (vm, node,
	b1, sizeof (*tr));
	tr->tunnel_id = tunnel_sw_if_index;
	if (!is_ipv6)
	{
	tr->length = ip4_1->length;
	tr->src.ip4.as_u32 = ip4_1->src_address.as_u32;
	tr->dst.ip4.as_u32 = ip4_1->dst_address.as_u32;
	}
	else
	{
	tr->length = ip6_1->payload_length;
	tr->src.ip6.as_u64[0] = ip6_1->src_address.as_u64[0];
	tr->src.ip6.as_u64[1] = ip6_1->src_address.as_u64[1];
	tr->dst.ip6.as_u64[0] = ip6_1->dst_address.as_u64[0];
	tr->dst.ip6.as_u64[1] = ip6_1->dst_address.as_u64[1];
	}
	}

	vlib_buffer_advance (b0, sizeof (*h0));
	vlib_buffer_advance (b1, sizeof (*h1));

	vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
	to_next, n_left_to_next,
	bi0, bi1, next0, next1);
	}

	while (n_left_from > 0 && n_left_to_next > 0)
	{
	u32 bi0;
	vlib_buffer_t *b0;
	gre_header_t *h0;
	ip4_header_t *ip4_0;
	ip6_header_t *ip6_0;
	u16 version0;
	int verr0;
	u32 i0, next0;
	gre_tunnel_key_t key0;

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

	b0 = vlib_get_buffer (vm, bi0);
	ip4_0 = vlib_buffer_get_current (b0);
	ip6_0 = (void *) ip4_0;

	if (!is_ipv6)
	{
	vlib_buffer_advance (b0, sizeof (*ip4_0));
	}
	else
	{
	vlib_buffer_advance (b0, sizeof (*ip6_0));
	}

	h0 = vlib_buffer_get_current (b0);

	i0 = sparse_vec_index (gm->next_by_protocol, h0->protocol);
	next0 = vec_elt (gm->next_by_protocol, i0).next_index;
	u8 ttype0 = vec_elt (gm->next_by_protocol, i0).tunnel_type;

	b0->error =
	node->errors[i0 == SPARSE_VEC_INVALID_INDEX
	? GRE_ERROR_UNKNOWN_PROTOCOL : GRE_ERROR_NONE];

	version0 = clib_net_to_host_u16 (h0->flags_and_version);
	verr0 = version0 & GRE_VERSION_MASK;
	b0->error = verr0 ? node->errors[GRE_ERROR_UNSUPPORTED_VERSION]
	: b0->error;
	next0 = verr0 ? GRE_INPUT_NEXT_DROP : next0;


	/* For IP payload we need to find source interface
	so we can increase counters and help forward node to
	pick right FIB */
	/* RPF check for ip4/ip6 input */
	if (PREDICT_TRUE (next0 > GRE_INPUT_NEXT_DROP))
	{
	if (is_ipv6)
	{
	gre_mk_key6 (&ip6_0->dst_address,
	&ip6_0->src_address,
	vnet_buffer (b0)->ip.fib_index,
	ttype0, 0, &key0.gtk_v6);
	}
	else
	{
	gre_mk_key4 (ip4_0->dst_address,
	ip4_0->src_address,
	vnet_buffer (b0)->ip.fib_index,
	ttype0, 0, &key0.gtk_v4);
	}

	if ((!is_ipv6 && !gre_match_key4 (&cached_tunnel_key.gtk_v4,
	&key0.gtk_v4)) \|\|
	(is_ipv6 && !gre_match_key6 (&cached_tunnel_key.gtk_v6,
	&key0.gtk_v6)))
	{
	gre_tunnel_t *t;
	uword *p;

	if (!is_ipv6)
	{
	p = hash_get_mem (gm->tunnel_by_key4, &key0.gtk_v4);
	}
	else
	{
	p = hash_get_mem (gm->tunnel_by_key6, &key0.gtk_v6);
	}
	if (!p)
	{
	next0 = GRE_INPUT_NEXT_DROP;
	b0->error = node->errors[GRE_ERROR_NO_SUCH_TUNNEL];
	goto drop;
	}
	t = pool_elt_at_index (gm->tunnels, p[0]);
	tunnel_sw_if_index = t->sw_if_index;

	cached_tunnel_sw_if_index = tunnel_sw_if_index;
	if (!is_ipv6)
	{
	cached_tunnel_key.gtk_v4 = key0.gtk_v4;
	}
	else
	{
	cached_tunnel_key.gtk_v6 = key0.gtk_v6;
	}
	}
	else
	{
	tunnel_sw_if_index = cached_tunnel_sw_if_index;
	}
	}
	else
	{
	next0 = GRE_INPUT_NEXT_DROP;
	goto drop;
	}
	len = vlib_buffer_length_in_chain (vm, b0);
	vlib_increment_combined_counter (im->combined_sw_if_counters
	+ VNET_INTERFACE_COUNTER_RX,
	thread_index,
	tunnel_sw_if_index,
	1 /* packets */ ,
	len /* bytes */ );

	vnet_buffer (b0)->sw_if_index[VLIB_RX] = tunnel_sw_if_index;

	drop:
	if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	{
	gre_rx_trace_t *tr = vlib_add_trace (vm, node,
	b0, sizeof (*tr));
	tr->tunnel_id = tunnel_sw_if_index;
	if (!is_ipv6)
	{
	tr->length = ip4_0->length;
	tr->src.ip4.as_u32 = ip4_0->src_address.as_u32;
	tr->dst.ip4.as_u32 = ip4_0->dst_address.as_u32;
	}
	else
	{
	tr->length = ip6_0->payload_length;
	tr->src.ip6.as_u64[0] = ip6_0->src_address.as_u64[0];
	tr->src.ip6.as_u64[1] = ip6_0->src_address.as_u64[1];
	tr->dst.ip6.as_u64[0] = ip6_0->dst_address.as_u64[0];
	tr->dst.ip6.as_u64[1] = ip6_0->dst_address.as_u64[1];
	}
	}

	vlib_buffer_advance (b0, sizeof (*h0));

	vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
	to_next, n_left_to_next,
	bi0, next0);
	}

	vlib_put_next_frame (vm, node, next_index, n_left_to_next);
	}
	vlib_node_increment_counter (vm,
	!is_ipv6 ? gre4_input_node.index :
	gre6_input_node.index, GRE_ERROR_PKTS_DECAP,
	from_frame->n_vectors);
	return from_frame->n_vectors;
	}

	VLIB_NODE_FN (gre4_input_node) (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame)
	{
	return gre_input (vm, node, from_frame, /* is_ip6 */ 0);
	}

	VLIB_NODE_FN (gre6_input_node) (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame)
	{
	return gre_input (vm, node, from_frame, /* is_ip6 */ 1);
	}

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

	/* INDENT-OFF */
	VLIB_REGISTER_NODE (gre4_input_node) = {
	.name = "gre4-input",
	/* Takes a vector of packets. */
	.vector_size = sizeof (u32),

	.n_errors = GRE_N_ERROR,
	.error_strings = gre_error_strings,

	.n_next_nodes = GRE_INPUT_N_NEXT,
	.next_nodes = {
	#define _(s,n) [GRE_INPUT_NEXT_##s] = n,
	foreach_gre_input_next
	#undef _
	},

	.format_buffer = format_gre_header_with_length,
	.format_trace = format_gre_rx_trace,
	.unformat_buffer = unformat_gre_header,
	};

	VLIB_REGISTER_NODE (gre6_input_node) = {
	.name = "gre6-input",
	/* Takes a vector of packets. */
	.vector_size = sizeof (u32),

	.runtime_data_bytes = sizeof (gre_input_runtime_t),

	.n_errors = GRE_N_ERROR,
	.error_strings = gre_error_strings,

	.n_next_nodes = GRE_INPUT_N_NEXT,
	.next_nodes = {
	#define _(s,n) [GRE_INPUT_NEXT_##s] = n,
	foreach_gre_input_next
	#undef _
	},

	.format_buffer = format_gre_header_with_length,
	.format_trace = format_gre_rx_trace,
	.unformat_buffer = unformat_gre_header,
	};
	/* INDENT-ON */

	#ifndef CLIB_MARCH_VARIANT
	void
	gre_register_input_protocol (vlib_main_t * vm,
	gre_protocol_t protocol, u32 node_index,
	gre_tunnel_type_t tunnel_type)
	{
	gre_main_t *em = &gre_main;
	gre_protocol_info_t *pi;
	next_info_t *n;
	u32 i;

	{
	clib_error_t *error = vlib_call_init_function (vm, gre_input_init);
	if (error)
	clib_error_report (error);
	}

	pi = gre_get_protocol_info (em, protocol);
	pi->node_index = node_index;
	pi->tunnel_type = tunnel_type;
	pi->next_index = vlib_node_add_next (vm, gre4_input_node.index, node_index);
	i = vlib_node_add_next (vm, gre6_input_node.index, node_index);
	ASSERT (i == pi->next_index);

	/* Setup gre protocol -> next index sparse vector mapping. */
	n = sparse_vec_validate (em->next_by_protocol,
	clib_host_to_net_u16 (protocol));
	n->next_index = pi->next_index;
	n->tunnel_type = tunnel_type;
	}

	static void
	gre_setup_node (vlib_main_t * vm, u32 node_index)
	{
	vlib_node_t *n = vlib_get_node (vm, node_index);
	pg_node_t *pn = pg_get_node (node_index);

	n->format_buffer = format_gre_header_with_length;
	n->unformat_buffer = unformat_gre_header;
	pn->unformat_edit = unformat_pg_gre_header;
	}

	static clib_error_t *
	gre_input_init (vlib_main_t * vm)
	{
	gre_main_t *gm = &gre_main;
	vlib_node_t ethernet_input, ip4_input, ip6_input, mpls_unicast_input;

	{
	clib_error_t *error;
	error = vlib_call_init_function (vm, gre_init);
	if (error)
	clib_error_report (error);
	}

	gre_setup_node (vm, gre4_input_node.index);
	gre_setup_node (vm, gre6_input_node.index);

	gm->next_by_protocol = sparse_vec_new
	( /* elt bytes */ sizeof (gm->next_by_protocol[0]),
	/* bits in index / BITS (((gre_header_t ) 0)->protocol));

	/* These could be moved to the supported protocol input node defn's */
	ethernet_input = vlib_get_node_by_name (vm, (u8 *) "ethernet-input");
	ASSERT (ethernet_input);
	ip4_input = vlib_get_node_by_name (vm, (u8 *) "ip4-input");
	ASSERT (ip4_input);
	ip6_input = vlib_get_node_by_name (vm, (u8 *) "ip6-input");
	ASSERT (ip6_input);
	mpls_unicast_input = vlib_get_node_by_name (vm, (u8 *) "mpls-input");
	ASSERT (mpls_unicast_input);

	gre_register_input_protocol (vm, GRE_PROTOCOL_teb,
	ethernet_input->index, GRE_TUNNEL_TYPE_TEB);

	gre_register_input_protocol (vm, GRE_PROTOCOL_ip4,
	ip4_input->index, GRE_TUNNEL_TYPE_L3);

	gre_register_input_protocol (vm, GRE_PROTOCOL_ip6,
	ip6_input->index, GRE_TUNNEL_TYPE_L3);

	gre_register_input_protocol (vm, GRE_PROTOCOL_mpls_unicast,
	mpls_unicast_input->index, GRE_TUNNEL_TYPE_L3);

	ip4_register_protocol (IP_PROTOCOL_GRE, gre4_input_node.index);
	ip6_register_protocol (IP_PROTOCOL_GRE, gre6_input_node.index);

	return 0;
	}

	VLIB_INIT_FUNCTION (gre_input_init);

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