/*
 * gre.h: types/functions for 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.
 */

#ifndef included_gre_h
#define included_gre_h

#include <vnet/vnet.h>
#include <vnet/gre/packet.h>
#include <vnet/ip/ip.h>
#include <vnet/pg/pg.h>
#include <vnet/ip/format.h>
#include <vnet/adj/adj_types.h>

extern vnet_hw_interface_class_t gre_hw_interface_class;

typedef enum {
#define gre_error(n,s) GRE_ERROR_##n,
#include <vnet/gre/error.def>
#undef gre_error
  GRE_N_ERROR,
} gre_error_t;

/**
 * A GRE payload protocol registration
 */
typedef struct {
  /** Name (a c string). */
  char * name;

  /** GRE protocol type in host byte order. */
  gre_protocol_t protocol;

  /** Node which handles this type. */
  u32 node_index;

  /** Next index for this type. */
  u32 next_index;
} gre_protocol_info_t;

/**
 * @brief The GRE tunnel type
 */
typedef enum gre_tunnel_tyoe_t_
{
  /**
   * L3 GRE (i.e. this tunnel is in L3 mode)
   */
  GRE_TUNNEL_TYPE_L3,
  /**
   * Transparent Ethernet Bridging - the tunnel is in L2 mode
   */
  GRE_TUNNEL_TYPE_TEB,
} gre_tunnel_type_t;

#define GRE_TUNNEL_TYPE_NAMES {    \
    [GRE_TUNNEL_TYPE_L3] = "L3",   \
    [GRE_TUNNEL_TYPE_TEB] = "TEB", \
}

#define GRE_TUNNEL_N_TYPES ((gre_tunnel_type_t)GRE_TUNNEL_TYPE_TEB+1)

/**
 * @brief A representation of a GRE tunnel
 */
typedef struct {
  /**
   * Linkage into the FIB object graph
   */
  fib_node_t node;

  /**
   * The tunnel's source/local address
   */
  ip46_address_t tunnel_src;
  /**
   * The tunnel's destination/remote address
   */
  fib_prefix_t tunnel_dst;
  /**
   * The FIB in which the src.dst address are present
   */
  u32 outer_fib_index;
  u32 hw_if_index;
  u32 sw_if_index;
  gre_tunnel_type_t type;

  /**
   * The FIB entry sourced by the tunnel for its destination prefix
   */
  fib_node_index_t fib_entry_index;

  /**
   * The tunnel is a child of the FIB entry for its desintion. This is
   * so it receives updates when the forwarding information for that entry
   * changes.
   * The tunnels sibling index on the FIB entry's dependency list.
   */
  u32 sibling_index;

  /**
   * on a L2 tunnel this is the VLIB arc from the L2-tx to the l2-midchain
   */
  u32 l2_tx_arc;

  /**
   * an L2 tunnel always rquires an L2 midchain. cache here for DP.
   */
  adj_index_t l2_adj_index;
} gre_tunnel_t;

/**
 * @brief GRE related global data
 */
typedef struct {
  /**
   * pool of tunnel instances
   */
  gre_tunnel_t *tunnels;

  /**
   * GRE payload protocol registrations
   */
  gre_protocol_info_t * protocol_infos;

  /**
   *  Hash tables mapping name/protocol to protocol info index.
   */
  uword * protocol_info_by_name, * protocol_info_by_protocol;

  /**
   * Hash mapping ipv4 src/dst addr pair to tunnel
   */
  uword * tunnel_by_key4;

  /**
     * Hash mapping ipv6 src/dst addr pair to tunnel
     */
    uword * tunnel_by_key6;

  /**
   * Free vlib hw_if_indices.
   * A free list per-tunnel type since the interfaces ctreated are fo different
   * types and we cannot change the type.
   */
  u32 * free_gre_tunnel_hw_if_indices[GRE_TUNNEL_N_TYPES];

  /**
   * Mapping from sw_if_index to tunnel index
   */
  u32 * tunnel_index_by_sw_if_index;

  /* Sparse vector mapping gre protocol in network byte order
     to next index. */
  u16 * next_by_protocol;

  /* convenience */
  vlib_main_t * vlib_main;
  vnet_main_t * vnet_main;
} gre_main_t;

/**
 * @brief IPv4 and GRE header.
 */
typedef CLIB_PACKED (struct {
  ip4_header_t ip4;
  gre_header_t gre;
}) ip4_and_gre_header_t;

/**
 * @brief IPv6 and GRE header.
 */
typedef CLIB_PACKED (struct {
  ip6_header_t ip6;
  gre_header_t gre;
}) ip6_and_gre_header_t;

always_inline gre_protocol_info_t *
gre_get_protocol_info (gre_main_t * em, gre_protocol_t protocol)
{
  uword * p = hash_get (em->protocol_info_by_protocol, protocol);
  return p ? vec_elt_at_index (em->protocol_infos, p[0]) : 0;
}

extern gre_main_t gre_main;

/* Register given node index to take input for given gre type. */
void
gre_register_input_type (vlib_main_t * vm,
			 gre_protocol_t protocol,
			 u32 node_index);

extern  clib_error_t * gre_interface_admin_up_down (vnet_main_t * vnm,
						    u32 hw_if_index,
						    u32 flags);

extern void gre_tunnel_stack (adj_index_t ai);
extern void gre_update_adj (vnet_main_t * vnm,
                            u32 sw_if_index,
                            adj_index_t ai);

format_function_t format_gre_protocol;
format_function_t format_gre_header;
format_function_t format_gre_header_with_length;

extern vlib_node_registration_t gre4_input_node;
extern vlib_node_registration_t gre6_input_node;
extern vnet_device_class_t gre_device_class;
extern vnet_device_class_t gre_device_teb_class;

/* Parse gre protocol as 0xXXXX or protocol name.
   In either host or network byte order. */
unformat_function_t unformat_gre_protocol_host_byte_order;
unformat_function_t unformat_gre_protocol_net_byte_order;

/* Parse gre header. */
unformat_function_t unformat_gre_header;
unformat_function_t unformat_pg_gre_header;

void
gre_register_input_protocol (vlib_main_t * vm,
			     gre_protocol_t protocol,
			     u32 node_index);

/* manually added to the interface output node in gre.c */
#define GRE_OUTPUT_NEXT_LOOKUP	1

typedef struct {
  u8 is_add;

  ip46_address_t src, dst;
  u8 is_ipv6;
  u32 outer_fib_id;
  u8 teb;
} vnet_gre_add_del_tunnel_args_t;

int vnet_gre_add_del_tunnel
  (vnet_gre_add_del_tunnel_args_t *a, u32 * sw_if_indexp);

#endif /* included_gre_h */