text: /*
   * 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.
   */
  /**
   * @file
   * @brief NAT plugin client-IP based session affinity for load-balancing
   */
  
  #ifndef __included_nat_affinity_h__
  #define __included_nat_affinity_h__
  
  #include <vnet/ip/ip.h>
  #include <vppinfra/bihash_16_8.h>
  #include <vppinfra/dlist.h>
  
  typedef struct
  {
    union
    {
      struct
      {
        ip4_address_t service_addr;
        ip4_address_t client_addr;
        /* align by making this 4 octets even though its a 1 octet field */
        u32 proto;
        /* align by making this 4 octets even though its a 2 octets field */
        u32 service_port;
      };
      u64 as_u64[2];
    };
  } nat_affinity_key_t;
  
  /* *INDENT-OFF* */
  typedef CLIB_PACKED(struct
  {
    nat_affinity_key_t key;
    u32 sticky_time;
    u32 ref_cnt;
    u32 per_service_index;
    u8 backend_index;
    f64 expire;
  }) nat_affinity_t;
  /* *INDENT-ON* */
  
  typedef struct
  {
    nat_affinity_t *affinity_pool;
    clib_bihash_16_8_t affinity_hash;
    clib_spinlock_t affinity_lock;
    dlist_elt_t *list_pool;
    vlib_main_t *vlib_main;
  } nat_affinity_main_t;
  
  extern nat_affinity_main_t nat_affinity_main;
  
  /**
   * @brief Get new affinity per service list head index.
   *
   * @returns new affinity per service list head index.
   */
  u32 nat_affinity_get_per_service_list_head_index (void);
  
  /**
   * @brief Flush all service affinity data.
   *
   * @param affinity_per_service_list_head_index Per sevice list head index.
   */
  void nat_affinity_flush_service (u32 affinity_per_service_list_head_index);
  
  /**
   * @brief Initialize NAT client-IP based affinity.
   *
   * @param vm vlib main.
   *
   * @return error code.
   */
  clib_error_t *nat_affinity_init (vlib_main_t * vm);
  
  /**
   * @brief Find service backend index for client-IP and take a reference
   *  counting lock.
   *
   * @param client_addr Client IP address.
   * @param service_addr Service IP address.
   * @param proto IP protocol number.
   * @param service_port Service L4 port number.
   * @param backend_index Service backend index for client-IP if found.
   *
   * @return 0 on success, non-zero value otherwise.
   */
  int nat_affinity_find_and_lock (ip4_address_t client_addr,
  				ip4_address_t service_addr, u8 proto,
  				u16 service_port, u8 * backend_index);
  
  /**
   * @brief Create affinity record and take reference counting lock.
   * @param client_addr Client IP address.
   * @param service_addr Service IP address.
   * @param proto IP protocol number.
   * @param service_port Service L4 port number.
   * @param backend_index Service backend index for client-IP.
   * @param sticky_time Affinity sticky time in seconds.
   * @param affinity_per_service_list_head_index Per sevice list head index.
   *
   * @return 0 on success, non-zero value otherwise.
   */
  int nat_affinity_create_and_lock (ip4_address_t client_addr,
  				  ip4_address_t service_addr, u8 proto,
  				  u16 service_port, u8 backend_index,
  				  u32 sticky_time,
  				  u32 affinity_per_service_list_head_index);
  /**
   * @brief Release a reference counting lock for affinity.
   *
   * @param client_addr Client IP address.
   * @param service_addr Service IP address.
   * @param proto IP protocol number.
   */
  void nat_affinity_unlock (ip4_address_t client_addr,
  			  ip4_address_t service_addr, u8 proto,
  			  u16 service_port);
  
  #endif /* __included_nat_affinity_h__ */
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  