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

 /*
  * gre.c: gre
  *
  * 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 <vnet/vnet.h>
 #include <vnet/gre/gre.h>
 #include <vnet/adj/adj_midchain.h>

 gre_main_t gre_main;

 typedef struct
 {
   union
   {
     ip4_and_gre_header_t ip4_and_gre;
     u64 as_u64[3];
   };
 } ip4_and_gre_union_t;

 typedef struct
 {
   union
   {
     ip6_and_gre_header_t ip6_and_gre;
     u64 as_u64[3];
   };
 } ip6_and_gre_union_t;


 /* Packet trace structure */
 typedef struct
 {
   /* Tunnel-id / index in tunnel vector */
   u32 tunnel_id;

   /* pkt length */
   u32 length;

   /* tunnel ip addresses */
   ip46_address_t src;
   ip46_address_t dst;
 } gre_tx_trace_t;

 u8 *
 format_gre_tx_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_tx_trace_t *t = va_arg (*args, gre_tx_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;
 }

 u8 *
 format_gre_protocol (u8 * s, va_list * args)
 {
   gre_protocol_t p = va_arg (*args, u32);
   gre_main_t *gm = &gre_main;
   gre_protocol_info_t *pi = gre_get_protocol_info (gm, p);

   if (pi)
     s = format (s, "%s", pi->name);
   else
     s = format (s, "0x%04x", p);

   return s;
 }

 u8 *
 format_gre_header_with_length (u8 * s, va_list * args)
 {
   gre_main_t *gm = &gre_main;
   gre_header_t *h = va_arg (*args, gre_header_t *);
   u32 max_header_bytes = va_arg (*args, u32);
   gre_protocol_t p = clib_net_to_host_u16 (h->protocol);
   u32 indent, header_bytes;

   header_bytes = sizeof (h[0]);
   if (max_header_bytes != 0 && header_bytes > max_header_bytes)
     return format (s, "gre header truncated");

   indent = format_get_indent (s);

   s = format (s, "GRE %U", format_gre_protocol, p);

   if (max_header_bytes != 0 && header_bytes > max_header_bytes)
     {
       gre_protocol_info_t *pi = gre_get_protocol_info (gm, p);
       vlib_node_t *node = vlib_get_node (gm->vlib_main, pi->node_index);
       if (node->format_buffer)
 	s = format (s, "\n%U%U",
 		    format_white_space, indent,
 		    node->format_buffer, (void *) (h + 1),
 		    max_header_bytes - header_bytes);
     }

   return s;
 }

 u8 *
 format_gre_header (u8 * s, va_list * args)
 {
   gre_header_t *h = va_arg (*args, gre_header_t *);
   return format (s, "%U", format_gre_header_with_length, h, 0);
 }

 /* Returns gre protocol as an int in host byte order. */
 uword
 unformat_gre_protocol_host_byte_order (unformat_input_t * input,
 				       va_list * args)
 {
   u16 *result = va_arg (*args, u16 *);
   gre_main_t *gm = &gre_main;
   int i;

   /* Named type. */
   if (unformat_user (input, unformat_vlib_number_by_name,
 		     gm->protocol_info_by_name, &i))
     {
       gre_protocol_info_t *pi = vec_elt_at_index (gm->protocol_infos, i);
       *result = pi->protocol;
       return 1;
     }

   return 0;
 }

 uword
 unformat_gre_protocol_net_byte_order (unformat_input_t * input,
 				      va_list * args)
 {
   u16 *result = va_arg (*args, u16 *);
   if (!unformat_user (input, unformat_gre_protocol_host_byte_order, result))
     return 0;
   *result = clib_host_to_net_u16 ((u16) * result);
   return 1;
 }

 uword
 unformat_gre_header (unformat_input_t * input, va_list * args)
 {
   u8 **result = va_arg (*args, u8 **);
   gre_header_t _h, *h = &_h;
   u16 p;

   if (!unformat (input, "%U", unformat_gre_protocol_host_byte_order, &p))
     return 0;

   h->protocol = clib_host_to_net_u16 (p);

   /* Add header to result. */
   {
     void *p;
     u32 n_bytes = sizeof (h[0]);

     vec_add2 (*result, p, n_bytes);
     clib_memcpy (p, h, n_bytes);
   }

   return 1;
 }

 static int
 gre_proto_from_vnet_link (vnet_link_t link)
 {
   switch (link)
     {
     case VNET_LINK_IP4:
       return (GRE_PROTOCOL_ip4);
     case VNET_LINK_IP6:
       return (GRE_PROTOCOL_ip6);
     case VNET_LINK_MPLS:
       return (GRE_PROTOCOL_mpls_unicast);
     case VNET_LINK_ETHERNET:
       return (GRE_PROTOCOL_teb);
     case VNET_LINK_ARP:
       return (GRE_PROTOCOL_arp);
     case VNET_LINK_NSH:
       ASSERT (0);
       break;
     }
   ASSERT (0);
   return (GRE_PROTOCOL_ip4);
 }

 static u8 *
 gre_build_rewrite (vnet_main_t * vnm,
 		   u32 sw_if_index,
 		   vnet_link_t link_type, const void *dst_address)
 {
   gre_main_t *gm = &gre_main;
   ip4_and_gre_header_t *h4;
   ip6_and_gre_header_t *h6;
   u8 *rewrite = NULL;
   gre_tunnel_t *t;
   u32 ti;
   u8 is_ipv6;

   ti = gm->tunnel_index_by_sw_if_index[sw_if_index];

   if (~0 == ti)
     /* not one of ours */
     return (0);

   t = pool_elt_at_index (gm->tunnels, ti);

   is_ipv6 = t->tunnel_dst.fp_proto == FIB_PROTOCOL_IP6 ? 1 : 0;

   if (!is_ipv6)
     {
       vec_validate (rewrite, sizeof (*h4) - 1);
       h4 = (ip4_and_gre_header_t *) rewrite;
       h4->gre.protocol =
 	clib_host_to_net_u16 (gre_proto_from_vnet_link (link_type));

       h4->ip4.ip_version_and_header_length = 0x45;
       h4->ip4.ttl = 254;
       h4->ip4.protocol = IP_PROTOCOL_GRE;
       /* fixup ip4 header length and checksum after-the-fact */
       h4->ip4.src_address.as_u32 = t->tunnel_src.ip4.as_u32;
       h4->ip4.dst_address.as_u32 = t->tunnel_dst.fp_addr.ip4.as_u32;
       h4->ip4.checksum = ip4_header_checksum (&h4->ip4);
     }
   else
     {
       vec_validate (rewrite, sizeof (*h6) - 1);
       h6 = (ip6_and_gre_header_t *) rewrite;
       h6->gre.protocol =
 	clib_host_to_net_u16 (gre_proto_from_vnet_link (link_type));

       h6->ip6.ip_version_traffic_class_and_flow_label =
 	clib_host_to_net_u32 (6 << 28);
       h6->ip6.hop_limit = 255;
       h6->ip6.protocol = IP_PROTOCOL_GRE;
       /* fixup ip6 header length and checksum after-the-fact */
       h6->ip6.src_address.as_u64[0] = t->tunnel_src.ip6.as_u64[0];
       h6->ip6.src_address.as_u64[1] = t->tunnel_src.ip6.as_u64[1];
       h6->ip6.dst_address.as_u64[0] = t->tunnel_dst.fp_addr.ip6.as_u64[0];
       h6->ip6.dst_address.as_u64[1] = t->tunnel_dst.fp_addr.ip6.as_u64[1];
     }

   return (rewrite);
 }

 #define is_v4_packet(_h) ((*(u8*) _h) & 0xF0) == 0x40

 void
 gre4_fixup (vlib_main_t * vm, ip_adjacency_t * adj, vlib_buffer_t * b0)
 {
   ip4_header_t *ip0;

   ip0 = vlib_buffer_get_current (b0);

   /* Fixup the checksum and len fields in the GRE tunnel encap
    * that was applied at the midchain node */
   ip0->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
   ip0->checksum = ip4_header_checksum (ip0);
 }

 void
 gre6_fixup (vlib_main_t * vm, ip_adjacency_t * adj, vlib_buffer_t * b0)
 {
   ip6_header_t *ip0;

   ip0 = vlib_buffer_get_current (b0);

   /* Fixup the payload length field in the GRE tunnel encap that was applied
    * at the midchain node */
   ip0->payload_length =
     clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0))
     - sizeof (*ip0);
 }

 void
 gre_update_adj (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai)
 {
   gre_main_t *gm = &gre_main;
   gre_tunnel_t *t;
   u32 ti;
   u8 is_ipv6;

   ti = gm->tunnel_index_by_sw_if_index[sw_if_index];
   t = pool_elt_at_index (gm->tunnels, ti);
   is_ipv6 = t->tunnel_dst.fp_proto == FIB_PROTOCOL_IP6 ? 1 : 0;

   adj_nbr_midchain_update_rewrite (ai, !is_ipv6 ? gre4_fixup : gre6_fixup,
 				   (VNET_LINK_ETHERNET ==
 				    adj_get_link_type (ai) ?
 				    ADJ_FLAG_MIDCHAIN_NO_COUNT :
 				    ADJ_FLAG_NONE), gre_build_rewrite (vnm,
 								       sw_if_index,
 								       adj_get_link_type
 								       (ai),
 								       NULL));

   gre_tunnel_stack (ai);
 }

 /**
  * @brief TX function. Only called L2. L3 traffic uses the adj-midchains
  */
 static uword
 gre_interface_tx_inline (vlib_main_t * vm,
 			 vlib_node_runtime_t * node, vlib_frame_t * frame)
 {
   gre_main_t *gm = &gre_main;
   u32 next_index;
   u32 *from, *to_next, n_left_from, n_left_to_next;
   vnet_interface_output_runtime_t *rd = (void *) node->runtime_data;
   const gre_tunnel_t *gt = pool_elt_at_index (gm->tunnels, rd->dev_instance);
   u8 is_ipv6 = gt->tunnel_dst.fp_proto == FIB_PROTOCOL_IP6 ? 1 : 0;

   /* Vector of buffer / pkt indices we're supposed to process */
   from = vlib_frame_vector_args (frame);

   /* Number of buffers / pkts */
   n_left_from = frame->n_vectors;

   /* Speculatively send the first buffer to the last disposition we used */
   next_index = node->cached_next_index;

   while (n_left_from > 0)
     {
       /* set up to enqueue to our disposition with index = next_index */
       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

       /*
        * FIXME DUAL LOOP
        */

       while (n_left_from > 0 && n_left_to_next > 0)
 	{
 	  vlib_buffer_t *b0;
 	  u32 bi0;

 	  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);

 	  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = gt->l2_adj_index;

 	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 	    {
 	      gre_tx_trace_t *tr = vlib_add_trace (vm, node,
 						   b0, sizeof (*tr));
 	      tr->tunnel_id = gt - gm->tunnels;
 	      tr->src = gt->tunnel_src;
 	      tr->dst = gt->tunnel_src;
 	      tr->length = vlib_buffer_length_in_chain (vm, b0);
 	    }

 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
 					   to_next, n_left_to_next,
 					   bi0, gt->l2_tx_arc);
 	}

       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_ENCAP, frame->n_vectors);

   return frame->n_vectors;
 }

 static uword
 gre_interface_tx (vlib_main_t * vm,
 		  vlib_node_runtime_t * node, vlib_frame_t * frame)
 {
   return (gre_interface_tx_inline (vm, node, frame));
 }

 static uword
 gre_teb_interface_tx (vlib_main_t * vm,
 		      vlib_node_runtime_t * node, vlib_frame_t * frame)
 {
   return (gre_interface_tx_inline (vm, node, frame));
 }

 static u8 *
 format_gre_tunnel_name (u8 * s, va_list * args)
 {
   u32 dev_instance = va_arg (*args, u32);
   return format (s, "gre%d", dev_instance);
 }

 static u8 *
 format_gre_tunnel_teb_name (u8 * s, va_list * args)
 {
   u32 dev_instance = va_arg (*args, u32);
   return format (s, "teb-gre%d", dev_instance);
 }

 static u8 *
 format_gre_device (u8 * s, va_list * args)
 {
   u32 dev_instance = va_arg (*args, u32);
   CLIB_UNUSED (int verbose) = va_arg (*args, int);

   s = format (s, "GRE tunnel: id %d\n", dev_instance);
   return s;
 }

 /* *INDENT-OFF* */
 VNET_DEVICE_CLASS (gre_device_class) = {
   .name = "GRE tunnel device",
   .format_device_name = format_gre_tunnel_name,
   .format_device = format_gre_device,
   .format_tx_trace = format_gre_tx_trace,
   .tx_function = gre_interface_tx,
   .admin_up_down_function = gre_interface_admin_up_down,
 #ifdef SOON
   .clear counter = 0;
 #endif
 };
 /* *INDENT-ON* */


 /* *INDENT-OFF* */
 VLIB_DEVICE_TX_FUNCTION_MULTIARCH (gre_device_class,
                                    gre_interface_tx)

 VNET_DEVICE_CLASS (gre_device_teb_class) = {
   .name = "GRE TEB tunnel device",
   .format_device_name = format_gre_tunnel_teb_name,
   .format_device = format_gre_device,
   .format_tx_trace = format_gre_tx_trace,
   .tx_function = gre_teb_interface_tx,
   .admin_up_down_function = gre_interface_admin_up_down,
 #ifdef SOON
   .clear counter = 0;
 #endif
 };

 /* *INDENT-ON* */

 /* *INDENT-OFF* */
 VLIB_DEVICE_TX_FUNCTION_MULTIARCH (gre_device_teb_class,
                                    gre_teb_interface_tx)

 VNET_HW_INTERFACE_CLASS (gre_hw_interface_class) = {
   .name = "GRE",
   .format_header = format_gre_header_with_length,
   .unformat_header = unformat_gre_header,
   .build_rewrite = gre_build_rewrite,
   .update_adjacency = gre_update_adj,
   .flags = VNET_HW_INTERFACE_CLASS_FLAG_P2P,
 };
 /* *INDENT-ON* */

 static void
 add_protocol (gre_main_t * gm, gre_protocol_t protocol, char *protocol_name)
 {
   gre_protocol_info_t *pi;
   u32 i;

   vec_add2 (gm->protocol_infos, pi, 1);
   i = pi - gm->protocol_infos;

   pi->name = protocol_name;
   pi->protocol = protocol;
   pi->next_index = pi->node_index = ~0;

   hash_set (gm->protocol_info_by_protocol, protocol, i);
   hash_set_mem (gm->protocol_info_by_name, pi->name, i);
 }

 static clib_error_t *
 gre_init (vlib_main_t * vm)
 {
   gre_main_t *gm = &gre_main;
   clib_error_t *error;
   ip_main_t *im = &ip_main;
   ip_protocol_info_t *pi;

   memset (gm, 0, sizeof (gm[0]));
   gm->vlib_main = vm;
   gm->vnet_main = vnet_get_main ();

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

   if ((error = vlib_call_init_function (vm, ip4_lookup_init)))
     return error;

   if ((error = vlib_call_init_function (vm, ip6_lookup_init)))
     return error;

   /* Set up the ip packet generator */
   pi = ip_get_protocol_info (im, IP_PROTOCOL_GRE);
   pi->format_header = format_gre_header;
   pi->unformat_pg_edit = unformat_pg_gre_header;

   gm->protocol_info_by_name = hash_create_string (0, sizeof (uword));
   gm->protocol_info_by_protocol = hash_create (0, sizeof (uword));
   gm->tunnel_by_key4 = hash_create (0, sizeof (uword));
   gm->tunnel_by_key6 = hash_create_mem (0, sizeof (u64[4]), sizeof (uword));

 #define _(n,s) add_protocol (gm, GRE_PROTOCOL_##s, #s);
   foreach_gre_protocol
 #undef _
     return vlib_call_init_function (vm, gre_input_init);
 }

 VLIB_INIT_FUNCTION (gre_init);

 gre_main_t *
 gre_get_main (vlib_main_t * vm)
 {
   vlib_call_init_function (vm, gre_init);
   return &gre_main;
 }


 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* gre.c: gre
	*
	* 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 <vnet/vnet.h>
	#include <vnet/gre/gre.h>
	#include <vnet/adj/adj_midchain.h>

	gre_main_t gre_main;

	typedef struct
	{
	union
	{
	ip4_and_gre_header_t ip4_and_gre;
	u64 as_u64[3];
	};
	} ip4_and_gre_union_t;

	typedef struct
	{
	union
	{
	ip6_and_gre_header_t ip6_and_gre;
	u64 as_u64[3];
	};
	} ip6_and_gre_union_t;


	/* Packet trace structure */
	typedef struct
	{
	/* Tunnel-id / index in tunnel vector */
	u32 tunnel_id;

	/* pkt length */
	u32 length;

	/* tunnel ip addresses */
	ip46_address_t src;
	ip46_address_t dst;
	} gre_tx_trace_t;

	u8 *
	format_gre_tx_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_tx_trace_t t = va_arg (args, gre_tx_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;
	}

	u8 *
	format_gre_protocol (u8 * s, va_list * args)
	{
	gre_protocol_t p = va_arg (*args, u32);
	gre_main_t *gm = &gre_main;
	gre_protocol_info_t *pi = gre_get_protocol_info (gm, p);

	if (pi)
	s = format (s, "%s", pi->name);
	else
	s = format (s, "0x%04x", p);

	return s;
	}

	u8 *
	format_gre_header_with_length (u8 * s, va_list * args)
	{
	gre_main_t *gm = &gre_main;
	gre_header_t h = va_arg (args, gre_header_t *);
	u32 max_header_bytes = va_arg (*args, u32);
	gre_protocol_t p = clib_net_to_host_u16 (h->protocol);
	u32 indent, header_bytes;

	header_bytes = sizeof (h[0]);
	if (max_header_bytes != 0 && header_bytes > max_header_bytes)
	return format (s, "gre header truncated");

	indent = format_get_indent (s);

	s = format (s, "GRE %U", format_gre_protocol, p);

	if (max_header_bytes != 0 && header_bytes > max_header_bytes)
	{
	gre_protocol_info_t *pi = gre_get_protocol_info (gm, p);
	vlib_node_t *node = vlib_get_node (gm->vlib_main, pi->node_index);
	if (node->format_buffer)
	s = format (s, "\n%U%U",
	format_white_space, indent,
	node->format_buffer, (void *) (h + 1),
	max_header_bytes - header_bytes);
	}

	return s;
	}

	u8 *
	format_gre_header (u8 * s, va_list * args)
	{
	gre_header_t h = va_arg (args, gre_header_t *);
	return format (s, "%U", format_gre_header_with_length, h, 0);
	}

	/* Returns gre protocol as an int in host byte order. */
	uword
	unformat_gre_protocol_host_byte_order (unformat_input_t * input,
	va_list * args)
	{
	u16 result = va_arg (args, u16 *);
	gre_main_t *gm = &gre_main;
	int i;

	/* Named type. */
	if (unformat_user (input, unformat_vlib_number_by_name,
	gm->protocol_info_by_name, &i))
	{
	gre_protocol_info_t *pi = vec_elt_at_index (gm->protocol_infos, i);
	*result = pi->protocol;
	return 1;
	}

	return 0;
	}

	uword
	unformat_gre_protocol_net_byte_order (unformat_input_t * input,
	va_list * args)
	{
	u16 result = va_arg (args, u16 *);
	if (!unformat_user (input, unformat_gre_protocol_host_byte_order, result))
	return 0;
	result = clib_host_to_net_u16 ((u16) result);
	return 1;
	}

	uword
	unformat_gre_header (unformat_input_t * input, va_list * args)
	{
	u8 *result = va_arg (args, u8 **);
	gre_header_t _h, *h = &_h;
	u16 p;

	if (!unformat (input, "%U", unformat_gre_protocol_host_byte_order, &p))
	return 0;

	h->protocol = clib_host_to_net_u16 (p);

	/* Add header to result. */
	{
	void *p;
	u32 n_bytes = sizeof (h[0]);

	vec_add2 (*result, p, n_bytes);
	clib_memcpy (p, h, n_bytes);
	}

	return 1;
	}

	static int
	gre_proto_from_vnet_link (vnet_link_t link)
	{
	switch (link)
	{
	case VNET_LINK_IP4:
	return (GRE_PROTOCOL_ip4);
	case VNET_LINK_IP6:
	return (GRE_PROTOCOL_ip6);
	case VNET_LINK_MPLS:
	return (GRE_PROTOCOL_mpls_unicast);
	case VNET_LINK_ETHERNET:
	return (GRE_PROTOCOL_teb);
	case VNET_LINK_ARP:
	return (GRE_PROTOCOL_arp);
	case VNET_LINK_NSH:
	ASSERT (0);
	break;
	}
	ASSERT (0);
	return (GRE_PROTOCOL_ip4);
	}

	static u8 *
	gre_build_rewrite (vnet_main_t * vnm,
	u32 sw_if_index,
	vnet_link_t link_type, const void *dst_address)
	{
	gre_main_t *gm = &gre_main;
	ip4_and_gre_header_t *h4;
	ip6_and_gre_header_t *h6;
	u8 *rewrite = NULL;
	gre_tunnel_t *t;
	u32 ti;
	u8 is_ipv6;

	ti = gm->tunnel_index_by_sw_if_index[sw_if_index];

	if (~0 == ti)
	/* not one of ours */
	return (0);

	t = pool_elt_at_index (gm->tunnels, ti);

	is_ipv6 = t->tunnel_dst.fp_proto == FIB_PROTOCOL_IP6 ? 1 : 0;

	if (!is_ipv6)
	{
	vec_validate (rewrite, sizeof (*h4) - 1);
	h4 = (ip4_and_gre_header_t *) rewrite;
	h4->gre.protocol =
	clib_host_to_net_u16 (gre_proto_from_vnet_link (link_type));

	h4->ip4.ip_version_and_header_length = 0x45;
	h4->ip4.ttl = 254;
	h4->ip4.protocol = IP_PROTOCOL_GRE;
	/* fixup ip4 header length and checksum after-the-fact */
	h4->ip4.src_address.as_u32 = t->tunnel_src.ip4.as_u32;
	h4->ip4.dst_address.as_u32 = t->tunnel_dst.fp_addr.ip4.as_u32;
	h4->ip4.checksum = ip4_header_checksum (&h4->ip4);
	}
	else
	{
	vec_validate (rewrite, sizeof (*h6) - 1);
	h6 = (ip6_and_gre_header_t *) rewrite;
	h6->gre.protocol =
	clib_host_to_net_u16 (gre_proto_from_vnet_link (link_type));

	h6->ip6.ip_version_traffic_class_and_flow_label =
	clib_host_to_net_u32 (6 << 28);
	h6->ip6.hop_limit = 255;
	h6->ip6.protocol = IP_PROTOCOL_GRE;
	/* fixup ip6 header length and checksum after-the-fact */
	h6->ip6.src_address.as_u64[0] = t->tunnel_src.ip6.as_u64[0];
	h6->ip6.src_address.as_u64[1] = t->tunnel_src.ip6.as_u64[1];
	h6->ip6.dst_address.as_u64[0] = t->tunnel_dst.fp_addr.ip6.as_u64[0];
	h6->ip6.dst_address.as_u64[1] = t->tunnel_dst.fp_addr.ip6.as_u64[1];
	}

	return (rewrite);
	}

	#define is_v4_packet(_h) (((u8) _h) & 0xF0) == 0x40

	void
	gre4_fixup (vlib_main_t * vm, ip_adjacency_t * adj, vlib_buffer_t * b0)
	{
	ip4_header_t *ip0;

	ip0 = vlib_buffer_get_current (b0);

	/* Fixup the checksum and len fields in the GRE tunnel encap
	* that was applied at the midchain node */
	ip0->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
	ip0->checksum = ip4_header_checksum (ip0);
	}

	void
	gre6_fixup (vlib_main_t * vm, ip_adjacency_t * adj, vlib_buffer_t * b0)
	{
	ip6_header_t *ip0;

	ip0 = vlib_buffer_get_current (b0);

	/* Fixup the payload length field in the GRE tunnel encap that was applied
	* at the midchain node */
	ip0->payload_length =
	clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0))
	- sizeof (*ip0);
	}

	void
	gre_update_adj (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai)
	{
	gre_main_t *gm = &gre_main;
	gre_tunnel_t *t;
	u32 ti;
	u8 is_ipv6;

	ti = gm->tunnel_index_by_sw_if_index[sw_if_index];
	t = pool_elt_at_index (gm->tunnels, ti);
	is_ipv6 = t->tunnel_dst.fp_proto == FIB_PROTOCOL_IP6 ? 1 : 0;

	adj_nbr_midchain_update_rewrite (ai, !is_ipv6 ? gre4_fixup : gre6_fixup,
	(VNET_LINK_ETHERNET ==
	adj_get_link_type (ai) ?
	ADJ_FLAG_MIDCHAIN_NO_COUNT :
	ADJ_FLAG_NONE), gre_build_rewrite (vnm,
	sw_if_index,
	adj_get_link_type
	(ai),
	NULL));

	gre_tunnel_stack (ai);
	}

	/**
	* @brief TX function. Only called L2. L3 traffic uses the adj-midchains
	*/
	static uword
	gre_interface_tx_inline (vlib_main_t * vm,
	vlib_node_runtime_t * node, vlib_frame_t * frame)
	{
	gre_main_t *gm = &gre_main;
	u32 next_index;
	u32 from, to_next, n_left_from, n_left_to_next;
	vnet_interface_output_runtime_t rd = (void ) node->runtime_data;
	const gre_tunnel_t *gt = pool_elt_at_index (gm->tunnels, rd->dev_instance);
	u8 is_ipv6 = gt->tunnel_dst.fp_proto == FIB_PROTOCOL_IP6 ? 1 : 0;

	/* Vector of buffer / pkt indices we're supposed to process */
	from = vlib_frame_vector_args (frame);

	/* Number of buffers / pkts */
	n_left_from = frame->n_vectors;

	/* Speculatively send the first buffer to the last disposition we used */
	next_index = node->cached_next_index;

	while (n_left_from > 0)
	{
	/* set up to enqueue to our disposition with index = next_index */
	vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

	/*
	* FIXME DUAL LOOP
	*/

	while (n_left_from > 0 && n_left_to_next > 0)
	{
	vlib_buffer_t *b0;
	u32 bi0;

	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);

	vnet_buffer (b0)->ip.adj_index[VLIB_TX] = gt->l2_adj_index;

	if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	{
	gre_tx_trace_t *tr = vlib_add_trace (vm, node,
	b0, sizeof (*tr));
	tr->tunnel_id = gt - gm->tunnels;
	tr->src = gt->tunnel_src;
	tr->dst = gt->tunnel_src;
	tr->length = vlib_buffer_length_in_chain (vm, b0);
	}

	vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
	to_next, n_left_to_next,
	bi0, gt->l2_tx_arc);
	}

	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_ENCAP, frame->n_vectors);

	return frame->n_vectors;
	}

	static uword
	gre_interface_tx (vlib_main_t * vm,
	vlib_node_runtime_t * node, vlib_frame_t * frame)
	{
	return (gre_interface_tx_inline (vm, node, frame));
	}

	static uword
	gre_teb_interface_tx (vlib_main_t * vm,
	vlib_node_runtime_t * node, vlib_frame_t * frame)
	{
	return (gre_interface_tx_inline (vm, node, frame));
	}

	static u8 *
	format_gre_tunnel_name (u8 * s, va_list * args)
	{
	u32 dev_instance = va_arg (*args, u32);
	return format (s, "gre%d", dev_instance);
	}

	static u8 *
	format_gre_tunnel_teb_name (u8 * s, va_list * args)
	{
	u32 dev_instance = va_arg (*args, u32);
	return format (s, "teb-gre%d", dev_instance);
	}

	static u8 *
	format_gre_device (u8 * s, va_list * args)
	{
	u32 dev_instance = va_arg (*args, u32);
	CLIB_UNUSED (int verbose) = va_arg (*args, int);

	s = format (s, "GRE tunnel: id %d\n", dev_instance);
	return s;
	}

	/* INDENT-OFF */
	VNET_DEVICE_CLASS (gre_device_class) = {
	.name = "GRE tunnel device",
	.format_device_name = format_gre_tunnel_name,
	.format_device = format_gre_device,
	.format_tx_trace = format_gre_tx_trace,
	.tx_function = gre_interface_tx,
	.admin_up_down_function = gre_interface_admin_up_down,
	#ifdef SOON
	.clear counter = 0;
	#endif
	};
	/* INDENT-ON */


	/* INDENT-OFF */
	VLIB_DEVICE_TX_FUNCTION_MULTIARCH (gre_device_class,
	gre_interface_tx)

	VNET_DEVICE_CLASS (gre_device_teb_class) = {
	.name = "GRE TEB tunnel device",
	.format_device_name = format_gre_tunnel_teb_name,
	.format_device = format_gre_device,
	.format_tx_trace = format_gre_tx_trace,
	.tx_function = gre_teb_interface_tx,
	.admin_up_down_function = gre_interface_admin_up_down,
	#ifdef SOON
	.clear counter = 0;
	#endif
	};

	/* INDENT-ON */

	/* INDENT-OFF */
	VLIB_DEVICE_TX_FUNCTION_MULTIARCH (gre_device_teb_class,
	gre_teb_interface_tx)

	VNET_HW_INTERFACE_CLASS (gre_hw_interface_class) = {
	.name = "GRE",
	.format_header = format_gre_header_with_length,
	.unformat_header = unformat_gre_header,
	.build_rewrite = gre_build_rewrite,
	.update_adjacency = gre_update_adj,
	.flags = VNET_HW_INTERFACE_CLASS_FLAG_P2P,
	};
	/* INDENT-ON */

	static void
	add_protocol (gre_main_t * gm, gre_protocol_t protocol, char *protocol_name)
	{
	gre_protocol_info_t *pi;
	u32 i;

	vec_add2 (gm->protocol_infos, pi, 1);
	i = pi - gm->protocol_infos;

	pi->name = protocol_name;
	pi->protocol = protocol;
	pi->next_index = pi->node_index = ~0;

	hash_set (gm->protocol_info_by_protocol, protocol, i);
	hash_set_mem (gm->protocol_info_by_name, pi->name, i);
	}

	static clib_error_t *
	gre_init (vlib_main_t * vm)
	{
	gre_main_t *gm = &gre_main;
	clib_error_t *error;
	ip_main_t *im = &ip_main;
	ip_protocol_info_t *pi;

	memset (gm, 0, sizeof (gm[0]));
	gm->vlib_main = vm;
	gm->vnet_main = vnet_get_main ();

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

	if ((error = vlib_call_init_function (vm, ip4_lookup_init)))
	return error;

	if ((error = vlib_call_init_function (vm, ip6_lookup_init)))
	return error;

	/* Set up the ip packet generator */
	pi = ip_get_protocol_info (im, IP_PROTOCOL_GRE);
	pi->format_header = format_gre_header;
	pi->unformat_pg_edit = unformat_pg_gre_header;

	gm->protocol_info_by_name = hash_create_string (0, sizeof (uword));
	gm->protocol_info_by_protocol = hash_create (0, sizeof (uword));
	gm->tunnel_by_key4 = hash_create (0, sizeof (uword));
	gm->tunnel_by_key6 = hash_create_mem (0, sizeof (u64[4]), sizeof (uword));

	#define _(n,s) add_protocol (gm, GRE_PROTOCOL_##s, #s);
	foreach_gre_protocol
	#undef _
	return vlib_call_init_function (vm, gre_input_init);
	}

	VLIB_INIT_FUNCTION (gre_init);

	gre_main_t *
	gre_get_main (vlib_main_t * vm)
	{
	vlib_call_init_function (vm, gre_init);
	return &gre_main;
	}


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