#ifndef LLC_H
  #define LLC_H
  /*
   * Copyright (c) 1997 by Procom Technology, Inc.
   * 		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   *
   * This program can be redistributed or modified under the terms of the
   * GNU General Public License as published by the Free Software Foundation.
   * This program is distributed without any warranty or implied warranty
   * of merchantability or fitness for a particular purpose.
   *
   * See the GNU General Public License for more details.
   */
  
  #include <linux/if.h>
  #include <linux/if_ether.h>
  #include <linux/list.h>
  #include <linux/spinlock.h>

  #include <linux/rculist_nulls.h>

  #include <linux/hash.h>
  #include <linux/jhash.h>

  #include <linux/atomic.h>

  struct net_device;
  struct packet_type;
  struct sk_buff;
  
  struct llc_addr {
  	unsigned char lsap;
  	unsigned char mac[IFHWADDRLEN];
  };
  
  #define LLC_SAP_STATE_INACTIVE	1
  #define LLC_SAP_STATE_ACTIVE	2

  #define LLC_SK_DEV_HASH_BITS 6
  #define LLC_SK_DEV_HASH_ENTRIES (1<<LLC_SK_DEV_HASH_BITS)

  #define LLC_SK_LADDR_HASH_BITS 6
  #define LLC_SK_LADDR_HASH_ENTRIES (1<<LLC_SK_LADDR_HASH_BITS)

  /**
   * struct llc_sap - Defines the SAP component
   *
   * @station - station this sap belongs to
   * @state - sap state
   * @p_bit - only lowest-order bit used
   * @f_bit - only lowest-order bit used
   * @laddr - SAP value in this 'lsap'
   * @node - entry in station sap_list
   * @sk_list - LLC sockets this one manages
   */
  struct llc_sap {
  	unsigned char	 state;
  	unsigned char	 p_bit;
  	unsigned char	 f_bit;

  	refcount_t		 refcnt;

  	int		 (*rcv_func)(struct sk_buff *skb,
  				     struct net_device *dev,

  				     struct packet_type *pt,
  				     struct net_device *orig_dev);

  	struct llc_addr	 laddr;
  	struct list_head node;

  	spinlock_t sk_lock;

  	int sk_count;
  	struct hlist_nulls_head sk_laddr_hash[LLC_SK_LADDR_HASH_ENTRIES];

  	struct hlist_head sk_dev_hash[LLC_SK_DEV_HASH_ENTRIES];

  	struct rcu_head rcu;

  };

  static inline
  struct hlist_head *llc_sk_dev_hash(struct llc_sap *sap, int ifindex)
  {
  	return &sap->sk_dev_hash[ifindex % LLC_SK_DEV_HASH_ENTRIES];
  }

  static inline
  u32 llc_sk_laddr_hashfn(struct llc_sap *sap, const struct llc_addr *laddr)
  {
  	return hash_32(jhash(laddr->mac, sizeof(laddr->mac), 0),
  		       LLC_SK_LADDR_HASH_BITS);
  }
  
  static inline
  struct hlist_nulls_head *llc_sk_laddr_hash(struct llc_sap *sap,
  					   const struct llc_addr *laddr)
  {
  	return &sap->sk_laddr_hash[llc_sk_laddr_hashfn(sap, laddr)];
  }

  #define LLC_DEST_INVALID         0      /* Invalid LLC PDU type */
  #define LLC_DEST_SAP             1      /* Type 1 goes here */
  #define LLC_DEST_CONN            2      /* Type 2 goes here */
  
  extern struct list_head llc_sap_list;

  int llc_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
  	    struct net_device *orig_dev);

  int llc_mac_hdr_init(struct sk_buff *skb, const unsigned char *sa,
  		     const unsigned char *da);

  void llc_add_pack(int type,
  		  void (*handler)(struct llc_sap *sap, struct sk_buff *skb));
  void llc_remove_pack(int type);

  void llc_set_station_handler(void (*handler)(struct sk_buff *skb));

  struct llc_sap *llc_sap_open(unsigned char lsap,
  			     int (*rcv)(struct sk_buff *skb,
  					struct net_device *dev,
  					struct packet_type *pt,
  					struct net_device *orig_dev));

  static inline void llc_sap_hold(struct llc_sap *sap)
  {

  	refcount_inc(&sap->refcnt);

  }

  static inline bool llc_sap_hold_safe(struct llc_sap *sap)
  {
  	return refcount_inc_not_zero(&sap->refcnt);
  }

  void llc_sap_close(struct llc_sap *sap);

  static inline void llc_sap_put(struct llc_sap *sap)
  {

  	if (refcount_dec_and_test(&sap->refcnt))

  		llc_sap_close(sap);
  }

  struct llc_sap *llc_sap_find(unsigned char sap_value);

  int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb,
  			      unsigned char *dmac, unsigned char dsap);

  void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb);
  void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb);

  void llc_station_init(void);
  void llc_station_exit(void);

  
  #ifdef CONFIG_PROC_FS

  int llc_proc_init(void);
  void llc_proc_exit(void);

  #else
  #define llc_proc_init()	(0)
  #define llc_proc_exit()	do { } while(0)
  #endif /* CONFIG_PROC_FS */

  #ifdef CONFIG_SYSCTL

  int llc_sysctl_init(void);
  void llc_sysctl_exit(void);

  
  extern int sysctl_llc2_ack_timeout;
  extern int sysctl_llc2_busy_timeout;
  extern int sysctl_llc2_p_timeout;
  extern int sysctl_llc2_rej_timeout;

  #else
  #define llc_sysctl_init() (0)
  #define llc_sysctl_exit() do { } while(0)
  #endif /* CONFIG_SYSCTL */

  #endif /* LLC_H */