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;

 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;
   u64 cached_tunnel_key4;
   u64 cached_tunnel_key6[4];
   u32 cached_tunnel_sw_if_index = 0, tunnel_sw_if_index = 0;

   u32 thread_index = vlib_get_thread_index();
   u32 len;
   vnet_interface_main_t *im = &gm->vnet_main->interface_main;

   if (!is_ipv6)
       memset (&cached_tunnel_key4, 0xff, sizeof(cached_tunnel_key4));
   else
       memset (&cached_tunnel_key6, 0xff, sizeof(cached_tunnel_key6));

   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;
           u32 ip4_tun_src0, ip4_tun_dst0;
           u32 ip4_tun_src1, ip4_tun_dst1;
           u64 ip6_tun_src0[2], ip6_tun_dst0[2];
           u64 ip6_tun_src1[2], ip6_tun_dst1[2];

 	  /* 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);
               /* Save src + dst ip4 address, e.g. for mpls-o-gre */
               ip4_tun_src0 = ip4_0->src_address.as_u32;
               ip4_tun_dst0 = ip4_0->dst_address.as_u32;
               ip4_tun_src1 = ip4_1->src_address.as_u32;
               ip4_tun_dst1 = ip4_1->dst_address.as_u32;

               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);
               /* Save src + dst ip6 address, e.g. for mpls-o-gre */
               ip6_tun_src0[0] = ip6_0->src_address.as_u64[0];
               ip6_tun_src0[1] = ip6_0->src_address.as_u64[1];
               ip6_tun_dst0[0] = ip6_0->dst_address.as_u64[0];
               ip6_tun_dst0[1] = ip6_0->dst_address.as_u64[1];
               ip6_tun_src1[0] = ip6_1->src_address.as_u64[0];
               ip6_tun_src1[1] = ip6_1->src_address.as_u64[1];
               ip6_tun_dst1[0] = ip6_1->dst_address.as_u64[0];
               ip6_tun_dst1[1] = ip6_1->dst_address.as_u64[1];

               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);
           next1 = vec_elt(gm->next_by_protocol, i1);

 	  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_IP4_INPUT
 			   || next0 == GRE_INPUT_NEXT_IP6_INPUT
 			   || next0 == GRE_INPUT_NEXT_ETHERNET_INPUT
 			   || next0 == GRE_INPUT_NEXT_MPLS_INPUT))
             {

               u64 key4, key6[4];
               if (!is_ipv6)
         	{
                   key4 = ((u64)(ip4_tun_dst0) << 32) | (u64)(ip4_tun_src0);
         	}
               else
         	{
                   key6[0] = ip6_tun_dst0[0];
                   key6[1] = ip6_tun_dst0[1];
                   key6[2] = ip6_tun_src0[0];
                   key6[3] = ip6_tun_src0[1];
         	}

               if ((!is_ipv6 && cached_tunnel_key4 != key4) ||
         	  (is_ipv6 && cached_tunnel_key6[0] != key6[0] &&
         	      cached_tunnel_key6[1] != key6[1] &&
         	      cached_tunnel_key6[2] != key6[2] &&
         	      cached_tunnel_key6[3] != key6[3]))
                 {
                   vnet_hw_interface_t * hi;
                   gre_tunnel_t * t;
                   uword * p;

                   if (!is_ipv6)
                     p = hash_get (gm->tunnel_by_key4, key4);
                   else
                     p = hash_get_mem (gm->tunnel_by_key6, key6);
                   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]);
                   hi = vnet_get_hw_interface (gm->vnet_main,
                             t->hw_if_index);
                   tunnel_sw_if_index = hi->sw_if_index;

                   cached_tunnel_sw_if_index = tunnel_sw_if_index;
                 }
               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_IP4_INPUT
 			   || next1 == GRE_INPUT_NEXT_IP6_INPUT
 			   || next1 == GRE_INPUT_NEXT_ETHERNET_INPUT
 			   || next1 == GRE_INPUT_NEXT_MPLS_INPUT))
             {
               u64 key4, key6[4];
               if (!is_ipv6)
         	{
                   key4 = ((u64)(ip4_tun_dst1) << 32) | (u64)(ip4_tun_src1);
         	}
               else
         	{
                   key6[0] = ip6_tun_dst1[0];
                   key6[1] = ip6_tun_dst1[1];
                   key6[2] = ip6_tun_src1[0];
                   key6[3] = ip6_tun_src1[1];
         	}

               if ((!is_ipv6 && cached_tunnel_key4 != key4) ||
         	  (is_ipv6 && cached_tunnel_key6[0] != key6[0] &&
         	      cached_tunnel_key6[1] != key6[1] &&
         	      cached_tunnel_key6[2] != key6[2] &&
         	      cached_tunnel_key6[3] != key6[3]))
                 {
                   vnet_hw_interface_t * hi;
                   gre_tunnel_t * t;
                   uword * p;

                   if (!is_ipv6)
                     p = hash_get (gm->tunnel_by_key4, key4);
                   else
                     p = hash_get_mem (gm->tunnel_by_key6, key6);

                   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]);
                   hi = vnet_get_hw_interface (gm->vnet_main,
                             t->hw_if_index);
                   tunnel_sw_if_index = hi->sw_if_index;

                   cached_tunnel_sw_if_index = tunnel_sw_if_index;
                 }
               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;
       u32 ip4_tun_src0, ip4_tun_dst0;
       u32 ip6_tun_src0[4], ip6_tun_dst0[4];

 	  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)
             {
               ip4_tun_src0 = ip4_0->src_address.as_u32;
               ip4_tun_dst0 = ip4_0->dst_address.as_u32;

               vlib_buffer_advance (b0, sizeof (*ip4_0));
             }
           else
             {
               ip6_tun_src0[0] = ip6_0->src_address.as_u64[0];
               ip6_tun_src0[1] = ip6_0->src_address.as_u64[1];
               ip6_tun_dst0[0] = ip6_0->dst_address.as_u64[0];
               ip6_tun_dst0[1] = ip6_0->dst_address.as_u64[1];

               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);

 	  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_IP4_INPUT
 			   || next0 == GRE_INPUT_NEXT_IP6_INPUT
 			   || next0 == GRE_INPUT_NEXT_ETHERNET_INPUT
 			   || next0 == GRE_INPUT_NEXT_MPLS_INPUT))
             {
               u64 key4, key6[4];
               if (!is_ipv6)
         	{
                   key4 = ((u64)(ip4_tun_dst0) << 32) | (u64)(ip4_tun_src0);
         	}
               else
                 {
                   key6[0] = ip6_tun_dst0[0];
                   key6[1] = ip6_tun_dst0[1];
                   key6[2] = ip6_tun_src0[0];
                   key6[3] = ip6_tun_src0[1];
                 }

               if ((!is_ipv6 && cached_tunnel_key4 != key4) ||
         	  (is_ipv6 && cached_tunnel_key6[0] != key6[0] &&
         	      cached_tunnel_key6[1] != key6[1] &&
         	      cached_tunnel_key6[2] != key6[2] &&
         	      cached_tunnel_key6[3] != key6[3]))
         	{
                   vnet_hw_interface_t * hi;
                   gre_tunnel_t * t;
                   uword * p;

                   if (!is_ipv6)
                     p = hash_get (gm->tunnel_by_key4, key4);
                   else
                     p = hash_get_mem (gm->tunnel_by_key6, key6);

                   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]);
                   hi = vnet_get_hw_interface (gm->vnet_main,
                             t->hw_if_index);
                   tunnel_sw_if_index = hi->sw_if_index;

                   cached_tunnel_sw_if_index = tunnel_sw_if_index;
                 }
               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;
 }

 static uword
 gre4_input (vlib_main_t * vm,
             vlib_node_runtime_t * node,
          vlib_frame_t * from_frame)
 {
    return gre_input(vm, node, from_frame, /* is_ip6 */ 0);
 }

 static uword
 gre6_input (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
 };

 VLIB_REGISTER_NODE (gre4_input_node) = {
   .function = gre4_input,
   .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) = {
   .function = gre6_input,
   .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,
 };

 VLIB_NODE_FUNCTION_MULTIARCH (gre4_input_node, gre4_input)
 VLIB_NODE_FUNCTION_MULTIARCH (gre6_input_node, gre6_input)

 void
 gre_register_input_protocol (vlib_main_t * vm,
 			     gre_protocol_t protocol,
 			     u32 node_index)
 {
   gre_main_t * em = &gre_main;
   gre_protocol_info_t * pi;
   u16 * 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->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[0] = pi->next_index;
 }

 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_register_input_protocol (vm, GRE_PROTOCOL_ip4,
                                ip4_input->index);

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

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

   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);
	/*
	* 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;

	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;
	u64 cached_tunnel_key4;
	u64 cached_tunnel_key6[4];
	u32 cached_tunnel_sw_if_index = 0, tunnel_sw_if_index = 0;

	u32 thread_index = vlib_get_thread_index();
	u32 len;
	vnet_interface_main_t *im = &gm->vnet_main->interface_main;

	if (!is_ipv6)
	memset (&cached_tunnel_key4, 0xff, sizeof(cached_tunnel_key4));
	else
	memset (&cached_tunnel_key6, 0xff, sizeof(cached_tunnel_key6));

	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;
	u32 ip4_tun_src0, ip4_tun_dst0;
	u32 ip4_tun_src1, ip4_tun_dst1;
	u64 ip6_tun_src0[2], ip6_tun_dst0[2];
	u64 ip6_tun_src1[2], ip6_tun_dst1[2];

	/* 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);
	/* Save src + dst ip4 address, e.g. for mpls-o-gre */
	ip4_tun_src0 = ip4_0->src_address.as_u32;
	ip4_tun_dst0 = ip4_0->dst_address.as_u32;
	ip4_tun_src1 = ip4_1->src_address.as_u32;
	ip4_tun_dst1 = ip4_1->dst_address.as_u32;

	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);
	/* Save src + dst ip6 address, e.g. for mpls-o-gre */
	ip6_tun_src0[0] = ip6_0->src_address.as_u64[0];
	ip6_tun_src0[1] = ip6_0->src_address.as_u64[1];
	ip6_tun_dst0[0] = ip6_0->dst_address.as_u64[0];
	ip6_tun_dst0[1] = ip6_0->dst_address.as_u64[1];
	ip6_tun_src1[0] = ip6_1->src_address.as_u64[0];
	ip6_tun_src1[1] = ip6_1->src_address.as_u64[1];
	ip6_tun_dst1[0] = ip6_1->dst_address.as_u64[0];
	ip6_tun_dst1[1] = ip6_1->dst_address.as_u64[1];

	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);
	next1 = vec_elt(gm->next_by_protocol, i1);

	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_IP4_INPUT
	\|\| next0 == GRE_INPUT_NEXT_IP6_INPUT
	\|\| next0 == GRE_INPUT_NEXT_ETHERNET_INPUT
	\|\| next0 == GRE_INPUT_NEXT_MPLS_INPUT))
	{

	u64 key4, key6[4];
	if (!is_ipv6)
	{
	key4 = ((u64)(ip4_tun_dst0) << 32) \| (u64)(ip4_tun_src0);
	}
	else
	{
	key6[0] = ip6_tun_dst0[0];
	key6[1] = ip6_tun_dst0[1];
	key6[2] = ip6_tun_src0[0];
	key6[3] = ip6_tun_src0[1];
	}

	if ((!is_ipv6 && cached_tunnel_key4 != key4) \|\|
	(is_ipv6 && cached_tunnel_key6[0] != key6[0] &&
	cached_tunnel_key6[1] != key6[1] &&
	cached_tunnel_key6[2] != key6[2] &&
	cached_tunnel_key6[3] != key6[3]))
	{
	vnet_hw_interface_t * hi;
	gre_tunnel_t * t;
	uword * p;

	if (!is_ipv6)
	p = hash_get (gm->tunnel_by_key4, key4);
	else
	p = hash_get_mem (gm->tunnel_by_key6, key6);
	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]);
	hi = vnet_get_hw_interface (gm->vnet_main,
	t->hw_if_index);
	tunnel_sw_if_index = hi->sw_if_index;

	cached_tunnel_sw_if_index = tunnel_sw_if_index;
	}
	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_IP4_INPUT
	\|\| next1 == GRE_INPUT_NEXT_IP6_INPUT
	\|\| next1 == GRE_INPUT_NEXT_ETHERNET_INPUT
	\|\| next1 == GRE_INPUT_NEXT_MPLS_INPUT))
	{
	u64 key4, key6[4];
	if (!is_ipv6)
	{
	key4 = ((u64)(ip4_tun_dst1) << 32) \| (u64)(ip4_tun_src1);
	}
	else
	{
	key6[0] = ip6_tun_dst1[0];
	key6[1] = ip6_tun_dst1[1];
	key6[2] = ip6_tun_src1[0];
	key6[3] = ip6_tun_src1[1];
	}

	if ((!is_ipv6 && cached_tunnel_key4 != key4) \|\|
	(is_ipv6 && cached_tunnel_key6[0] != key6[0] &&
	cached_tunnel_key6[1] != key6[1] &&
	cached_tunnel_key6[2] != key6[2] &&
	cached_tunnel_key6[3] != key6[3]))
	{
	vnet_hw_interface_t * hi;
	gre_tunnel_t * t;
	uword * p;

	if (!is_ipv6)
	p = hash_get (gm->tunnel_by_key4, key4);
	else
	p = hash_get_mem (gm->tunnel_by_key6, key6);

	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]);
	hi = vnet_get_hw_interface (gm->vnet_main,
	t->hw_if_index);
	tunnel_sw_if_index = hi->sw_if_index;

	cached_tunnel_sw_if_index = tunnel_sw_if_index;
	}
	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;
	u32 ip4_tun_src0, ip4_tun_dst0;
	u32 ip6_tun_src0[4], ip6_tun_dst0[4];

	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)
	{
	ip4_tun_src0 = ip4_0->src_address.as_u32;
	ip4_tun_dst0 = ip4_0->dst_address.as_u32;

	vlib_buffer_advance (b0, sizeof (*ip4_0));
	}
	else
	{
	ip6_tun_src0[0] = ip6_0->src_address.as_u64[0];
	ip6_tun_src0[1] = ip6_0->src_address.as_u64[1];
	ip6_tun_dst0[0] = ip6_0->dst_address.as_u64[0];
	ip6_tun_dst0[1] = ip6_0->dst_address.as_u64[1];

	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);

	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_IP4_INPUT
	\|\| next0 == GRE_INPUT_NEXT_IP6_INPUT
	\|\| next0 == GRE_INPUT_NEXT_ETHERNET_INPUT
	\|\| next0 == GRE_INPUT_NEXT_MPLS_INPUT))
	{
	u64 key4, key6[4];
	if (!is_ipv6)
	{
	key4 = ((u64)(ip4_tun_dst0) << 32) \| (u64)(ip4_tun_src0);
	}
	else
	{
	key6[0] = ip6_tun_dst0[0];
	key6[1] = ip6_tun_dst0[1];
	key6[2] = ip6_tun_src0[0];
	key6[3] = ip6_tun_src0[1];
	}

	if ((!is_ipv6 && cached_tunnel_key4 != key4) \|\|
	(is_ipv6 && cached_tunnel_key6[0] != key6[0] &&
	cached_tunnel_key6[1] != key6[1] &&
	cached_tunnel_key6[2] != key6[2] &&
	cached_tunnel_key6[3] != key6[3]))
	{
	vnet_hw_interface_t * hi;
	gre_tunnel_t * t;
	uword * p;

	if (!is_ipv6)
	p = hash_get (gm->tunnel_by_key4, key4);
	else
	p = hash_get_mem (gm->tunnel_by_key6, key6);

	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]);
	hi = vnet_get_hw_interface (gm->vnet_main,
	t->hw_if_index);
	tunnel_sw_if_index = hi->sw_if_index;

	cached_tunnel_sw_if_index = tunnel_sw_if_index;
	}
	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;
	}

	static uword
	gre4_input (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame)
	{
	return gre_input(vm, node, from_frame, /* is_ip6 */ 0);
	}

	static uword
	gre6_input (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
	};

	VLIB_REGISTER_NODE (gre4_input_node) = {
	.function = gre4_input,
	.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) = {
	.function = gre6_input,
	.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,
	};

	VLIB_NODE_FUNCTION_MULTIARCH (gre4_input_node, gre4_input)
	VLIB_NODE_FUNCTION_MULTIARCH (gre6_input_node, gre6_input)

	void
	gre_register_input_protocol (vlib_main_t * vm,
	gre_protocol_t protocol,
	u32 node_index)
	{
	gre_main_t * em = &gre_main;
	gre_protocol_info_t * pi;
	u16 * 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->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[0] = pi->next_index;
	}

	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_register_input_protocol (vm, GRE_PROTOCOL_ip4,
	ip4_input->index);

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

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

	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);