src/vnet/ipip/sixrd.c - fdio/vpp - Gitiles

 /*
  * sixrd.c - 6RD specific functions (RFC5969)
  *
  * Copyright (c) 2018 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.
  */

 /**
  * This code supports the following sixrd modes:
  *
  * 32 EA bits (Complete IPv4 address is embedded):
  *   ea_bits_len = 32
  * IPv4 suffix is embedded:
  *   ea_bits_len = < 32
  * No embedded address bits (1:1 mode):
  *   ea_bits_len = 0
  */

 #include "ipip.h"
 #include <vlibapi/api.h>
 #include <vlibmemory/api.h>
 #include <vnet/adj/adj.h>
 #include <vnet/adj/adj_delegate.h>
 #include <vnet/adj/adj_midchain.h>
 #include <vnet/dpo/lookup_dpo.h>
 #include <vnet/fib/fib_table.h>
 #include <vnet/fib/ip6_fib.h>
 #include <vnet/plugin/plugin.h>

 extern vlib_node_registration_t ip4_sixrd_node;

 /**
  * Adj delegate data
  */
 typedef struct sixrd_adj_delegate_t_
 {
   u32 adj_index;
   fib_node_t sixrd_node;
   fib_node_index_t sixrd_fib_entry_index;
   u32 sixrd_sibling;
 } sixrd_adj_delegate_t;

 /**
  * Pool of delegate structs
  */
 static sixrd_adj_delegate_t *sixrd_adj_delegate_pool;

 /**
  * Adj delegate registered type
  */
 static adj_delegate_type_t sixrd_adj_delegate_type;

 /**
  * FIB node registered type
  */
 static fib_node_type_t sixrd_fib_node_type;

 static inline sixrd_adj_delegate_t *
 sixrd_adj_from_base (adj_delegate_t * ad)
 {
   if (ad == NULL)
     return (NULL);
   return (pool_elt_at_index (sixrd_adj_delegate_pool, ad->ad_index));
 }

 static inline const sixrd_adj_delegate_t *
 sixrd_adj_from_const_base (const adj_delegate_t * ad)
 {
   if (ad == NULL)
     {
       return (NULL);
     }
   return (pool_elt_at_index (sixrd_adj_delegate_pool, ad->ad_index));
 }

 static void
 sixrd_fixup (vlib_main_t * vm, ip_adjacency_t * adj, vlib_buffer_t * b0,
 	     const void *data)
 {
   ip4_header_t *ip4 = vlib_buffer_get_current (b0);
   ip6_header_t *ip6 = vlib_buffer_get_current (b0) + sizeof (ip4_header_t);
   const ipip_tunnel_t *t = data;

   ip4->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
   ip4->dst_address.as_u32 =
     sixrd_get_addr_net (t, ip6->dst_address.as_u64[0]);
   ip4->checksum = ip4_header_checksum (ip4);
 }

 static void
 ip6ip_fixup (vlib_main_t * vm, ip_adjacency_t * adj, vlib_buffer_t * b0,
 	     const void *data)
 {
   const ipip_tunnel_t *t = data;
   ip4_header_t *ip4 = vlib_buffer_get_current (b0);
   ip4->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
   ip4->dst_address.as_u32 =
     sixrd_get_addr_net (t, adj->sub_type.nbr.next_hop.as_u64[0]);
   ip4->checksum = ip4_header_checksum (ip4);
 }

 static u8 *
 sixrd_build_rewrite (vnet_main_t * vnm, u32 sw_if_index,
 		     vnet_link_t link_type, const void *dst_address)
 {
   u8 *rewrite = NULL;
   ipip_tunnel_t *t;

   t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);
   if (!t)
     return 0;

   vec_validate (rewrite, sizeof (ip4_header_t) - 1);
   ip4_header_t *ip4 = (ip4_header_t *) rewrite;
   ip4->ip_version_and_header_length = 0x45;
   ip4->ttl = 64;
   ip4->protocol = IP_PROTOCOL_IPV6;
   /* fixup ip4 header length and checksum after-the-fact */
   ip4->src_address.as_u32 = t->tunnel_src.ip4.as_u32;
   ip4->dst_address.as_u32 = 0;
   ip4->checksum = ip4_header_checksum (ip4);

   return rewrite;
 }

 static void
 ip6ip_tunnel_stack (adj_index_t ai, u32 fib_entry_index)
 {
   ip_adjacency_t *adj = adj_get (ai);
   ipip_tunnel_t *t;
   u32 sw_if_index = adj->rewrite_header.sw_if_index;

   t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);
   if (!t)
     return;

   /*
    * find the adjacency that is contributed by the FIB entry
    * that this tunnel resolves via, and use it as the next adj
    * in the midchain
    */
   if (vnet_hw_interface_get_flags (vnet_get_main (), t->hw_if_index) &
       VNET_HW_INTERFACE_FLAG_LINK_UP)
     {
       adj_nbr_midchain_stack (ai,
 			      fib_entry_contribute_ip_forwarding
 			      (fib_entry_index));
     }
   else
     {
       adj_nbr_midchain_unstack (ai);
     }
 }

 static void
 sixrd_tunnel_stack (adj_index_t ai, u32 fib_index)
 {
   dpo_id_t dpo = DPO_INVALID;
   ip_adjacency_t *adj = adj_get (ai);
   u32 sw_if_index = adj->rewrite_header.sw_if_index;

   ipip_tunnel_t *t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);
   if (!t)
     return;

   lookup_dpo_add_or_lock_w_fib_index (fib_index, DPO_PROTO_IP4,
 				      LOOKUP_UNICAST, LOOKUP_INPUT_DST_ADDR,
 				      LOOKUP_TABLE_FROM_CONFIG, &dpo);
   adj_nbr_midchain_stack (ai, &dpo);
 }

 const static ip46_address_t sixrd_special_nh = {
   .ip6 = {
 	  .as_u64 = {
 		     [0] = 0xffffffffffffffff,
 		     [1] = 0xffffffffffffffff,
 		     },
 	  },
 };

 static void
 sixrd_update_adj (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai)
 {
   ip_adjacency_t *adj = adj_get (ai);
   ipip_tunnel_t *t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);

   /* Not our tunnel */
   if (!t)
     return;
   if (!memcmp (&sixrd_special_nh, &adj->sub_type.nbr.next_hop,
 	       sizeof (sixrd_special_nh)))
     {
       adj_nbr_midchain_update_rewrite (ai, sixrd_fixup, t, ADJ_FLAG_NONE,
 				       sixrd_build_rewrite (vnm, sw_if_index,
 							    adj_get_link_type
 							    (ai), NULL));
       sixrd_tunnel_stack (ai, t->fib_index);
     }
   else
     {
       sixrd_adj_delegate_t *sixrd_ad;
       ip4_address_t da4;

       da4.as_u32 =
 	sixrd_get_addr_net (t, adj->sub_type.nbr.next_hop.as_u64[0]);

       fib_prefix_t pfx = {
 	.fp_proto = FIB_PROTOCOL_IP4,
 	.fp_len = 32,
 	.fp_addr = {
 		    .ip4 = da4,
 		    }
 	,
       };

       adj_nbr_midchain_update_rewrite (ai, ip6ip_fixup, t, ADJ_FLAG_NONE,
 				       sixrd_build_rewrite (vnm, sw_if_index,
 							    adj_get_link_type
 							    (ai), NULL));

       sixrd_ad =
 	sixrd_adj_from_base (adj_delegate_get (adj, sixrd_adj_delegate_type));
       if (sixrd_ad == NULL)
 	{
 	  pool_get (sixrd_adj_delegate_pool, sixrd_ad);
 	  fib_node_init (&sixrd_ad->sixrd_node, sixrd_fib_node_type);
 	  sixrd_ad->adj_index = ai;
 	  sixrd_ad->sixrd_fib_entry_index =
 	    fib_table_entry_special_add (t->fib_index, &pfx, FIB_SOURCE_RR,
 					 FIB_ENTRY_FLAG_NONE);
 	  sixrd_ad->sixrd_sibling =
 	    fib_entry_child_add (sixrd_ad->sixrd_fib_entry_index,
 				 sixrd_fib_node_type,
 				 sixrd_ad - sixrd_adj_delegate_pool);

 	  adj_delegate_add (adj, sixrd_adj_delegate_type,
 			    sixrd_ad - sixrd_adj_delegate_pool);

 	  ip6ip_tunnel_stack (ai, sixrd_ad->sixrd_fib_entry_index);
 	}
     }
 }

 clib_error_t *
 sixrd_interface_admin_up_down (vnet_main_t * vnm, u32 hw_if_index, u32 flags)
 {
   /* Always up */
   vnet_hw_interface_set_flags (vnm, hw_if_index,
 			       VNET_HW_INTERFACE_FLAG_LINK_UP);
   return /* no error */ 0;
 }

 /* *INDENT-OFF* */
 VNET_HW_INTERFACE_CLASS(sixrd_hw_interface_class) = {
     .name = "ip6ip-6rd",
     .build_rewrite = sixrd_build_rewrite,
     .update_adjacency = sixrd_update_adj,
 };

 VNET_DEVICE_CLASS(sixrd_device_class) = {
     .name = "ip6ip-6rd",
     .admin_up_down_function = sixrd_interface_admin_up_down,
 #ifdef SOON
     .clear counter = 0;
 #endif
 }
 ;
 /* *INDENT-ON* */

 int
 sixrd_add_tunnel (ip6_address_t * ip6_prefix, u8 ip6_prefix_len,
 		  ip4_address_t * ip4_prefix, u8 ip4_prefix_len,
 		  ip4_address_t * ip4_src, bool security_check,
 		  u32 fib_index, u32 * sw_if_index)
 {
   ipip_main_t *gm = &ipip_main;
   ipip_tunnel_t *t;

   if (fib_index == ~0)
     return VNET_API_ERROR_NO_SUCH_FIB;

   if ((ip6_prefix_len + 32 - ip4_prefix_len) > 64)
     return VNET_API_ERROR_INVALID_VALUE;

   /* Tunnel already configured */
   ip46_address_t src = ip46_address_initializer, dst =
     ip46_address_initializer;
   ip_set (&src, ip4_src, true);
   ipip_tunnel_key_t key = {.transport = IPIP_TRANSPORT_IP4,
     .fib_index = fib_index,
     .src = src,
     .dst = dst
   };

   t = ipip_tunnel_db_find (&key);
   if (t)
     return VNET_API_ERROR_IF_ALREADY_EXISTS;

   /* Get tunnel index */
   pool_get_aligned (gm->tunnels, t, CLIB_CACHE_LINE_BYTES);
   memset (t, 0, sizeof (*t));
   u32 t_idx = t - gm->tunnels;	/* tunnel index (or instance) */

   /* Init tunnel struct */
   t->mode = IPIP_MODE_6RD;
   t->sixrd.ip4_prefix.as_u32 = ip4_prefix->as_u32;
   t->sixrd.ip4_prefix_len = ip4_prefix_len;
   t->sixrd.ip6_prefix = *ip6_prefix;
   t->sixrd.ip6_prefix_len = ip6_prefix_len;
   t->tunnel_src = src;
   t->sixrd.security_check = security_check;
   t->sixrd.shift =
     (ip4_prefix_len < 32) ? 64 - ip6_prefix_len - (32 - ip4_prefix_len) : 0;

   /* Create interface */
   u32 hw_if_index =
     vnet_register_interface (vnet_get_main (), sixrd_device_class.index,
 			     t_idx,
 			     sixrd_hw_interface_class.index, t_idx);

   /* Default the interface to up and enable IPv6 (payload) */
   vnet_hw_interface_t *hi =
     vnet_get_hw_interface (vnet_get_main (), hw_if_index);
   t->hw_if_index = hw_if_index;
   t->fib_index = fib_index;
   t->sw_if_index = hi->sw_if_index;
   t->dev_instance = t_idx;
   t->user_instance = t_idx;

   hi->max_l3_packet_bytes[VLIB_RX] = hi->max_l3_packet_bytes[VLIB_TX] = 1480;

   ipip_tunnel_db_add (t, &key);

   vec_validate_init_empty (gm->tunnel_index_by_sw_if_index, hi->sw_if_index,
 			   ~0);
   gm->tunnel_index_by_sw_if_index[hi->sw_if_index] = t_idx;

   vnet_hw_interface_set_flags (vnet_get_main (), hw_if_index,
 			       VNET_HW_INTERFACE_FLAG_LINK_UP);
   vnet_sw_interface_set_flags (vnet_get_main (), hi->sw_if_index,
 			       VNET_SW_INTERFACE_FLAG_ADMIN_UP);
   ip6_sw_interface_enable_disable (hi->sw_if_index, true);

   /* Create IPv6 route/adjacency */
   fib_prefix_t pfx6 = {
     .fp_proto = FIB_PROTOCOL_IP6,
     .fp_len = t->sixrd.ip6_prefix_len,
     .fp_addr = {
 		.ip6 = t->sixrd.ip6_prefix,
 		}
     ,
   };

   fib_table_entry_update_one_path (fib_index, &pfx6, FIB_SOURCE_CLI,
 				   FIB_ENTRY_FLAG_ATTACHED, DPO_PROTO_IP6,
 				   &sixrd_special_nh, hi->sw_if_index, ~0, 1,
 				   NULL, FIB_ROUTE_PATH_FLAG_NONE);

   *sw_if_index = hi->sw_if_index;

   if (!gm->ip4_protocol_registered)
     {
       vlib_node_t *ipip4_input =
 	vlib_get_node_by_name (gm->vlib_main, (u8 *) "ipip4-input");
       ASSERT (ipip4_input);
       ip4_register_protocol (IP_PROTOCOL_IPV6, ipip4_input->index);
     }
   return 0;
 }

 /*
  * sixrd_del_tunnel
  */
 int
 sixrd_del_tunnel (u32 sw_if_index)
 {
   ipip_main_t *gm = &ipip_main;
   ipip_tunnel_t *t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);

   if (!t)
     {
       clib_warning ("SIXRD tunnel delete: tunnel does not exist: %d",
 		    sw_if_index);
       return -1;
     }

   fib_prefix_t pfx6 = {
     .fp_proto = FIB_PROTOCOL_IP6,
     .fp_len = t->sixrd.ip6_prefix_len,
     .fp_addr = {
 		.ip6 = t->sixrd.ip6_prefix,
 		}
     ,
   };
   fib_table_entry_special_remove (0, &pfx6, FIB_SOURCE_CLI);
   vnet_sw_interface_set_flags (vnet_get_main (), t->sw_if_index,
 			       0 /* down */ );
   ip6_sw_interface_enable_disable (t->sw_if_index, false);
   gm->tunnel_index_by_sw_if_index[t->sw_if_index] = ~0;

   vnet_delete_hw_interface (vnet_get_main (), t->hw_if_index);
   ipip_tunnel_db_remove (t);
   pool_put (gm->tunnels, t);

   return 0;
 }

 static void
 sixrd_adj_delegate_adj_deleted (adj_delegate_t * aed)
 {
   sixrd_adj_delegate_t *sixrd_ad;

   sixrd_ad = sixrd_adj_from_base (aed);
   fib_entry_child_remove (sixrd_ad->sixrd_fib_entry_index,
 			  sixrd_ad->sixrd_sibling);
   fib_table_entry_delete_index (sixrd_ad->sixrd_fib_entry_index,
 				FIB_SOURCE_RR);
   pool_put (sixrd_adj_delegate_pool, sixrd_ad);
 }

 static u8 *
 sixrd_adj_delegate_format (const adj_delegate_t * aed, u8 * s)
 {
   const sixrd_adj_delegate_t *sixrd_ad;

   sixrd_ad = sixrd_adj_from_const_base (aed);
   s = format (s, "SIXRD:[fib-entry:%d]", sixrd_ad->sixrd_fib_entry_index);

   return (s);
 }

 static void
 sixrd_fib_node_last_lock_gone (fib_node_t * node)
 {
   /* top of the dependency tree, locks not managed here. */
 }

 static sixrd_adj_delegate_t *
 sixrd_adj_delegate_from_fib_node (fib_node_t * node)
 {
   return ((sixrd_adj_delegate_t *) (((char *) node) -
 				    STRUCT_OFFSET_OF (sixrd_adj_delegate_t,
 						      sixrd_node)));
 }

 static fib_node_back_walk_rc_t
 sixrd_fib_node_back_walk_notify (fib_node_t * node,
 				 fib_node_back_walk_ctx_t * ctx)
 {
   sixrd_adj_delegate_t *sixrd_ad;

   sixrd_ad = sixrd_adj_delegate_from_fib_node (node);
   ip6ip_tunnel_stack (sixrd_ad->adj_index, sixrd_ad->sixrd_fib_entry_index);

   return (FIB_NODE_BACK_WALK_CONTINUE);
 }

 /**
  * Function definition to get a FIB node from its index
  */
 static fib_node_t *
 sixrd_fib_node_get (fib_node_index_t index)
 {
   sixrd_adj_delegate_t *sixrd_ad;

   sixrd_ad = pool_elt_at_index (sixrd_adj_delegate_pool, index);

   return (&sixrd_ad->sixrd_node);
 }

 /**
  * VFT registered with the adjacency delegate
  */
 const static adj_delegate_vft_t sixrd_adj_delegate_vft = {
   .adv_adj_deleted = sixrd_adj_delegate_adj_deleted,
   .adv_format = sixrd_adj_delegate_format,
 };

 /**
  * VFT registered with the FIB node for the adj delegate
  */
 const static fib_node_vft_t sixrd_fib_node_vft = {
   .fnv_get = sixrd_fib_node_get,
   .fnv_last_lock = sixrd_fib_node_last_lock_gone,
   .fnv_back_walk = sixrd_fib_node_back_walk_notify,
 };

 static clib_error_t *
 sixrd_init (vlib_main_t * vm)
 {
   clib_error_t *error = 0;

   /* Make sure the IPIP tunnel subsystem is initialised */
   vlib_call_init_function (vm, ipip_init);

   sixrd_adj_delegate_type =
     adj_delegate_register_new_type (&sixrd_adj_delegate_vft);
   sixrd_fib_node_type = fib_node_register_new_type (&sixrd_fib_node_vft);

   return error;
 }

 VLIB_INIT_FUNCTION (sixrd_init);

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* sixrd.c - 6RD specific functions (RFC5969)
	*
	* Copyright (c) 2018 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.
	*/

	/**
	* This code supports the following sixrd modes:
	*
	* 32 EA bits (Complete IPv4 address is embedded):
	* ea_bits_len = 32
	* IPv4 suffix is embedded:
	* ea_bits_len = < 32
	* No embedded address bits (1:1 mode):
	* ea_bits_len = 0
	*/

	#include "ipip.h"
	#include <vlibapi/api.h>
	#include <vlibmemory/api.h>
	#include <vnet/adj/adj.h>
	#include <vnet/adj/adj_delegate.h>
	#include <vnet/adj/adj_midchain.h>
	#include <vnet/dpo/lookup_dpo.h>
	#include <vnet/fib/fib_table.h>
	#include <vnet/fib/ip6_fib.h>
	#include <vnet/plugin/plugin.h>

	extern vlib_node_registration_t ip4_sixrd_node;

	/**
	* Adj delegate data
	*/
	typedef struct sixrd_adj_delegate_t_
	{
	u32 adj_index;
	fib_node_t sixrd_node;
	fib_node_index_t sixrd_fib_entry_index;
	u32 sixrd_sibling;
	} sixrd_adj_delegate_t;

	/**
	* Pool of delegate structs
	*/
	static sixrd_adj_delegate_t *sixrd_adj_delegate_pool;

	/**
	* Adj delegate registered type
	*/
	static adj_delegate_type_t sixrd_adj_delegate_type;

	/**
	* FIB node registered type
	*/
	static fib_node_type_t sixrd_fib_node_type;

	static inline sixrd_adj_delegate_t *
	sixrd_adj_from_base (adj_delegate_t * ad)
	{
	if (ad == NULL)
	return (NULL);
	return (pool_elt_at_index (sixrd_adj_delegate_pool, ad->ad_index));
	}

	static inline const sixrd_adj_delegate_t *
	sixrd_adj_from_const_base (const adj_delegate_t * ad)
	{
	if (ad == NULL)
	{
	return (NULL);
	}
	return (pool_elt_at_index (sixrd_adj_delegate_pool, ad->ad_index));
	}

	static void
	sixrd_fixup (vlib_main_t * vm, ip_adjacency_t * adj, vlib_buffer_t * b0,
	const void *data)
	{
	ip4_header_t *ip4 = vlib_buffer_get_current (b0);
	ip6_header_t *ip6 = vlib_buffer_get_current (b0) + sizeof (ip4_header_t);
	const ipip_tunnel_t *t = data;

	ip4->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
	ip4->dst_address.as_u32 =
	sixrd_get_addr_net (t, ip6->dst_address.as_u64[0]);
	ip4->checksum = ip4_header_checksum (ip4);
	}

	static void
	ip6ip_fixup (vlib_main_t * vm, ip_adjacency_t * adj, vlib_buffer_t * b0,
	const void *data)
	{
	const ipip_tunnel_t *t = data;
	ip4_header_t *ip4 = vlib_buffer_get_current (b0);
	ip4->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
	ip4->dst_address.as_u32 =
	sixrd_get_addr_net (t, adj->sub_type.nbr.next_hop.as_u64[0]);
	ip4->checksum = ip4_header_checksum (ip4);
	}

	static u8 *
	sixrd_build_rewrite (vnet_main_t * vnm, u32 sw_if_index,
	vnet_link_t link_type, const void *dst_address)
	{
	u8 *rewrite = NULL;
	ipip_tunnel_t *t;

	t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);
	if (!t)
	return 0;

	vec_validate (rewrite, sizeof (ip4_header_t) - 1);
	ip4_header_t ip4 = (ip4_header_t ) rewrite;
	ip4->ip_version_and_header_length = 0x45;
	ip4->ttl = 64;
	ip4->protocol = IP_PROTOCOL_IPV6;
	/* fixup ip4 header length and checksum after-the-fact */
	ip4->src_address.as_u32 = t->tunnel_src.ip4.as_u32;
	ip4->dst_address.as_u32 = 0;
	ip4->checksum = ip4_header_checksum (ip4);

	return rewrite;
	}

	static void
	ip6ip_tunnel_stack (adj_index_t ai, u32 fib_entry_index)
	{
	ip_adjacency_t *adj = adj_get (ai);
	ipip_tunnel_t *t;
	u32 sw_if_index = adj->rewrite_header.sw_if_index;

	t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);
	if (!t)
	return;

	/*
	* find the adjacency that is contributed by the FIB entry
	* that this tunnel resolves via, and use it as the next adj
	* in the midchain
	*/
	if (vnet_hw_interface_get_flags (vnet_get_main (), t->hw_if_index) &
	VNET_HW_INTERFACE_FLAG_LINK_UP)
	{
	adj_nbr_midchain_stack (ai,
	fib_entry_contribute_ip_forwarding
	(fib_entry_index));
	}
	else
	{
	adj_nbr_midchain_unstack (ai);
	}
	}

	static void
	sixrd_tunnel_stack (adj_index_t ai, u32 fib_index)
	{
	dpo_id_t dpo = DPO_INVALID;
	ip_adjacency_t *adj = adj_get (ai);
	u32 sw_if_index = adj->rewrite_header.sw_if_index;

	ipip_tunnel_t *t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);
	if (!t)
	return;

	lookup_dpo_add_or_lock_w_fib_index (fib_index, DPO_PROTO_IP4,
	LOOKUP_UNICAST, LOOKUP_INPUT_DST_ADDR,
	LOOKUP_TABLE_FROM_CONFIG, &dpo);
	adj_nbr_midchain_stack (ai, &dpo);
	}

	const static ip46_address_t sixrd_special_nh = {
	.ip6 = {
	.as_u64 = {
	[0] = 0xffffffffffffffff,
	[1] = 0xffffffffffffffff,
	},
	},
	};

	static void
	sixrd_update_adj (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai)
	{
	ip_adjacency_t *adj = adj_get (ai);
	ipip_tunnel_t *t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);

	/* Not our tunnel */
	if (!t)
	return;
	if (!memcmp (&sixrd_special_nh, &adj->sub_type.nbr.next_hop,
	sizeof (sixrd_special_nh)))
	{
	adj_nbr_midchain_update_rewrite (ai, sixrd_fixup, t, ADJ_FLAG_NONE,
	sixrd_build_rewrite (vnm, sw_if_index,
	adj_get_link_type
	(ai), NULL));
	sixrd_tunnel_stack (ai, t->fib_index);
	}
	else
	{
	sixrd_adj_delegate_t *sixrd_ad;
	ip4_address_t da4;

	da4.as_u32 =
	sixrd_get_addr_net (t, adj->sub_type.nbr.next_hop.as_u64[0]);

	fib_prefix_t pfx = {
	.fp_proto = FIB_PROTOCOL_IP4,
	.fp_len = 32,
	.fp_addr = {
	.ip4 = da4,
	}
	,
	};

	adj_nbr_midchain_update_rewrite (ai, ip6ip_fixup, t, ADJ_FLAG_NONE,
	sixrd_build_rewrite (vnm, sw_if_index,
	adj_get_link_type
	(ai), NULL));

	sixrd_ad =
	sixrd_adj_from_base (adj_delegate_get (adj, sixrd_adj_delegate_type));
	if (sixrd_ad == NULL)
	{
	pool_get (sixrd_adj_delegate_pool, sixrd_ad);
	fib_node_init (&sixrd_ad->sixrd_node, sixrd_fib_node_type);
	sixrd_ad->adj_index = ai;
	sixrd_ad->sixrd_fib_entry_index =
	fib_table_entry_special_add (t->fib_index, &pfx, FIB_SOURCE_RR,
	FIB_ENTRY_FLAG_NONE);
	sixrd_ad->sixrd_sibling =
	fib_entry_child_add (sixrd_ad->sixrd_fib_entry_index,
	sixrd_fib_node_type,
	sixrd_ad - sixrd_adj_delegate_pool);

	adj_delegate_add (adj, sixrd_adj_delegate_type,
	sixrd_ad - sixrd_adj_delegate_pool);

	ip6ip_tunnel_stack (ai, sixrd_ad->sixrd_fib_entry_index);
	}
	}
	}

	clib_error_t *
	sixrd_interface_admin_up_down (vnet_main_t * vnm, u32 hw_if_index, u32 flags)
	{
	/* Always up */
	vnet_hw_interface_set_flags (vnm, hw_if_index,
	VNET_HW_INTERFACE_FLAG_LINK_UP);
	return /* no error */ 0;
	}

	/* INDENT-OFF */
	VNET_HW_INTERFACE_CLASS(sixrd_hw_interface_class) = {
	.name = "ip6ip-6rd",
	.build_rewrite = sixrd_build_rewrite,
	.update_adjacency = sixrd_update_adj,
	};

	VNET_DEVICE_CLASS(sixrd_device_class) = {
	.name = "ip6ip-6rd",
	.admin_up_down_function = sixrd_interface_admin_up_down,
	#ifdef SOON
	.clear counter = 0;
	#endif
	}
	;
	/* INDENT-ON */

	int
	sixrd_add_tunnel (ip6_address_t * ip6_prefix, u8 ip6_prefix_len,
	ip4_address_t * ip4_prefix, u8 ip4_prefix_len,
	ip4_address_t * ip4_src, bool security_check,
	u32 fib_index, u32 * sw_if_index)
	{
	ipip_main_t *gm = &ipip_main;
	ipip_tunnel_t *t;

	if (fib_index == ~0)
	return VNET_API_ERROR_NO_SUCH_FIB;

	if ((ip6_prefix_len + 32 - ip4_prefix_len) > 64)
	return VNET_API_ERROR_INVALID_VALUE;

	/* Tunnel already configured */
	ip46_address_t src = ip46_address_initializer, dst =
	ip46_address_initializer;
	ip_set (&src, ip4_src, true);
	ipip_tunnel_key_t key = {.transport = IPIP_TRANSPORT_IP4,
	.fib_index = fib_index,
	.src = src,
	.dst = dst
	};

	t = ipip_tunnel_db_find (&key);
	if (t)
	return VNET_API_ERROR_IF_ALREADY_EXISTS;

	/* Get tunnel index */
	pool_get_aligned (gm->tunnels, t, CLIB_CACHE_LINE_BYTES);
	memset (t, 0, sizeof (*t));
	u32 t_idx = t - gm->tunnels; /* tunnel index (or instance) */

	/* Init tunnel struct */
	t->mode = IPIP_MODE_6RD;
	t->sixrd.ip4_prefix.as_u32 = ip4_prefix->as_u32;
	t->sixrd.ip4_prefix_len = ip4_prefix_len;
	t->sixrd.ip6_prefix = *ip6_prefix;
	t->sixrd.ip6_prefix_len = ip6_prefix_len;
	t->tunnel_src = src;
	t->sixrd.security_check = security_check;
	t->sixrd.shift =
	(ip4_prefix_len < 32) ? 64 - ip6_prefix_len - (32 - ip4_prefix_len) : 0;

	/* Create interface */
	u32 hw_if_index =
	vnet_register_interface (vnet_get_main (), sixrd_device_class.index,
	t_idx,
	sixrd_hw_interface_class.index, t_idx);

	/* Default the interface to up and enable IPv6 (payload) */
	vnet_hw_interface_t *hi =
	vnet_get_hw_interface (vnet_get_main (), hw_if_index);
	t->hw_if_index = hw_if_index;
	t->fib_index = fib_index;
	t->sw_if_index = hi->sw_if_index;
	t->dev_instance = t_idx;
	t->user_instance = t_idx;

	hi->max_l3_packet_bytes[VLIB_RX] = hi->max_l3_packet_bytes[VLIB_TX] = 1480;

	ipip_tunnel_db_add (t, &key);

	vec_validate_init_empty (gm->tunnel_index_by_sw_if_index, hi->sw_if_index,
	~0);
	gm->tunnel_index_by_sw_if_index[hi->sw_if_index] = t_idx;

	vnet_hw_interface_set_flags (vnet_get_main (), hw_if_index,
	VNET_HW_INTERFACE_FLAG_LINK_UP);
	vnet_sw_interface_set_flags (vnet_get_main (), hi->sw_if_index,
	VNET_SW_INTERFACE_FLAG_ADMIN_UP);
	ip6_sw_interface_enable_disable (hi->sw_if_index, true);

	/* Create IPv6 route/adjacency */
	fib_prefix_t pfx6 = {
	.fp_proto = FIB_PROTOCOL_IP6,
	.fp_len = t->sixrd.ip6_prefix_len,
	.fp_addr = {
	.ip6 = t->sixrd.ip6_prefix,
	}
	,
	};

	fib_table_entry_update_one_path (fib_index, &pfx6, FIB_SOURCE_CLI,
	FIB_ENTRY_FLAG_ATTACHED, DPO_PROTO_IP6,
	&sixrd_special_nh, hi->sw_if_index, ~0, 1,
	NULL, FIB_ROUTE_PATH_FLAG_NONE);

	*sw_if_index = hi->sw_if_index;

	if (!gm->ip4_protocol_registered)
	{
	vlib_node_t *ipip4_input =
	vlib_get_node_by_name (gm->vlib_main, (u8 *) "ipip4-input");
	ASSERT (ipip4_input);
	ip4_register_protocol (IP_PROTOCOL_IPV6, ipip4_input->index);
	}
	return 0;
	}

	/*
	* sixrd_del_tunnel
	*/
	int
	sixrd_del_tunnel (u32 sw_if_index)
	{
	ipip_main_t *gm = &ipip_main;
	ipip_tunnel_t *t = ipip_tunnel_db_find_by_sw_if_index (sw_if_index);

	if (!t)
	{
	clib_warning ("SIXRD tunnel delete: tunnel does not exist: %d",
	sw_if_index);
	return -1;
	}

	fib_prefix_t pfx6 = {
	.fp_proto = FIB_PROTOCOL_IP6,
	.fp_len = t->sixrd.ip6_prefix_len,
	.fp_addr = {
	.ip6 = t->sixrd.ip6_prefix,
	}
	,
	};
	fib_table_entry_special_remove (0, &pfx6, FIB_SOURCE_CLI);
	vnet_sw_interface_set_flags (vnet_get_main (), t->sw_if_index,
	0 /* down */ );
	ip6_sw_interface_enable_disable (t->sw_if_index, false);
	gm->tunnel_index_by_sw_if_index[t->sw_if_index] = ~0;

	vnet_delete_hw_interface (vnet_get_main (), t->hw_if_index);
	ipip_tunnel_db_remove (t);
	pool_put (gm->tunnels, t);

	return 0;
	}

	static void
	sixrd_adj_delegate_adj_deleted (adj_delegate_t * aed)
	{
	sixrd_adj_delegate_t *sixrd_ad;

	sixrd_ad = sixrd_adj_from_base (aed);
	fib_entry_child_remove (sixrd_ad->sixrd_fib_entry_index,
	sixrd_ad->sixrd_sibling);
	fib_table_entry_delete_index (sixrd_ad->sixrd_fib_entry_index,
	FIB_SOURCE_RR);
	pool_put (sixrd_adj_delegate_pool, sixrd_ad);
	}

	static u8 *
	sixrd_adj_delegate_format (const adj_delegate_t * aed, u8 * s)
	{
	const sixrd_adj_delegate_t *sixrd_ad;

	sixrd_ad = sixrd_adj_from_const_base (aed);
	s = format (s, "SIXRD:[fib-entry:%d]", sixrd_ad->sixrd_fib_entry_index);

	return (s);
	}

	static void
	sixrd_fib_node_last_lock_gone (fib_node_t * node)
	{
	/* top of the dependency tree, locks not managed here. */
	}

	static sixrd_adj_delegate_t *
	sixrd_adj_delegate_from_fib_node (fib_node_t * node)
	{
	return ((sixrd_adj_delegate_t ) (((char ) node) -
	STRUCT_OFFSET_OF (sixrd_adj_delegate_t,
	sixrd_node)));
	}

	static fib_node_back_walk_rc_t
	sixrd_fib_node_back_walk_notify (fib_node_t * node,
	fib_node_back_walk_ctx_t * ctx)
	{
	sixrd_adj_delegate_t *sixrd_ad;

	sixrd_ad = sixrd_adj_delegate_from_fib_node (node);
	ip6ip_tunnel_stack (sixrd_ad->adj_index, sixrd_ad->sixrd_fib_entry_index);

	return (FIB_NODE_BACK_WALK_CONTINUE);
	}

	/**
	* Function definition to get a FIB node from its index
	*/
	static fib_node_t *
	sixrd_fib_node_get (fib_node_index_t index)
	{
	sixrd_adj_delegate_t *sixrd_ad;

	sixrd_ad = pool_elt_at_index (sixrd_adj_delegate_pool, index);

	return (&sixrd_ad->sixrd_node);
	}

	/**
	* VFT registered with the adjacency delegate
	*/
	const static adj_delegate_vft_t sixrd_adj_delegate_vft = {
	.adv_adj_deleted = sixrd_adj_delegate_adj_deleted,
	.adv_format = sixrd_adj_delegate_format,
	};

	/**
	* VFT registered with the FIB node for the adj delegate
	*/
	const static fib_node_vft_t sixrd_fib_node_vft = {
	.fnv_get = sixrd_fib_node_get,
	.fnv_last_lock = sixrd_fib_node_last_lock_gone,
	.fnv_back_walk = sixrd_fib_node_back_walk_notify,
	};

	static clib_error_t *
	sixrd_init (vlib_main_t * vm)
	{
	clib_error_t *error = 0;

	/* Make sure the IPIP tunnel subsystem is initialised */
	vlib_call_init_function (vm, ipip_init);

	sixrd_adj_delegate_type =
	adj_delegate_register_new_type (&sixrd_adj_delegate_vft);
	sixrd_fib_node_type = fib_node_register_new_type (&sixrd_fib_node_vft);

	return error;
	}

	VLIB_INIT_FUNCTION (sixrd_init);

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