/*
   * INET		An implementation of the TCP/IP protocol suite for the LINUX
   *		operating system.  INET is implemented using the  BSD Socket
   *		interface as the means of communication with the user level.
   *
   *		Definitions for a generic INET TIMEWAIT sock
   *
   *		From code originally in net/tcp.h
   *
   *		This program is free software; you can redistribute it and/or
   *		modify it under the terms of the GNU General Public License
   *		as published by the Free Software Foundation; either version
   *		2 of the License, or (at your option) any later version.
   */
  #ifndef _INET_TIMEWAIT_SOCK_
  #define _INET_TIMEWAIT_SOCK_

  #include <linux/kmemcheck.h>

  #include <linux/list.h>

  #include <linux/timer.h>

  #include <linux/types.h>

  #include <linux/workqueue.h>

  #include <net/inet_sock.h>

  #include <net/sock.h>
  #include <net/tcp_states.h>

  #include <net/timewait_sock.h>

  #include <linux/atomic.h>

  struct inet_hashinfo;
  
  #define INET_TWDR_RECYCLE_SLOTS_LOG	5
  #define INET_TWDR_RECYCLE_SLOTS		(1 << INET_TWDR_RECYCLE_SLOTS_LOG)
  
  /*
   * If time > 4sec, it is "slow" path, no recycling is required,
   * so that we select tick to get range about 4 seconds.
   */
  #if HZ <= 16 || HZ > 4096
  # error Unsupported: HZ <= 16 or HZ > 4096
  #elif HZ <= 32
  # define INET_TWDR_RECYCLE_TICK (5 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  #elif HZ <= 64
  # define INET_TWDR_RECYCLE_TICK (6 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  #elif HZ <= 128
  # define INET_TWDR_RECYCLE_TICK (7 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  #elif HZ <= 256
  # define INET_TWDR_RECYCLE_TICK (8 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  #elif HZ <= 512
  # define INET_TWDR_RECYCLE_TICK (9 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  #elif HZ <= 1024
  # define INET_TWDR_RECYCLE_TICK (10 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  #elif HZ <= 2048
  # define INET_TWDR_RECYCLE_TICK (11 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  #else
  # define INET_TWDR_RECYCLE_TICK (12 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  #endif
  
  /* TIME_WAIT reaping mechanism. */
  #define INET_TWDR_TWKILL_SLOTS	8 /* Please keep this a power of 2. */
  
  #define INET_TWDR_TWKILL_QUOTA 100
  
  struct inet_timewait_death_row {
  	/* Short-time timewait calendar */
  	int			twcal_hand;

  	unsigned long		twcal_jiffie;

  	struct timer_list	twcal_timer;
  	struct hlist_head	twcal_row[INET_TWDR_RECYCLE_SLOTS];
  
  	spinlock_t		death_lock;
  	int			tw_count;
  	int			period;
  	u32			thread_slots;
  	struct work_struct	twkill_work;
  	struct timer_list	tw_timer;
  	int			slot;
  	struct hlist_head	cells[INET_TWDR_TWKILL_SLOTS];
  	struct inet_hashinfo 	*hashinfo;
  	int			sysctl_tw_recycle;
  	int			sysctl_max_tw_buckets;
  };

  extern void inet_twdr_hangman(unsigned long data);

  extern void inet_twdr_twkill_work(struct work_struct *work);

  extern void inet_twdr_twcal_tick(unsigned long data);

  struct inet_bind_bucket;
  
  /*
   * This is a TIME_WAIT sock. It works around the memory consumption
   * problems of sockets in such a state on heavily loaded servers, but
   * without violating the protocol specification.
   */
  struct inet_timewait_sock {
  	/*
  	 * Now struct sock also uses sock_common, so please just
  	 * don't add nothing before this first member (__tw_common) --acme
  	 */
  	struct sock_common	__tw_common;
  #define tw_family		__tw_common.skc_family
  #define tw_state		__tw_common.skc_state
  #define tw_reuse		__tw_common.skc_reuse
  #define tw_bound_dev_if		__tw_common.skc_bound_dev_if

  #define tw_node			__tw_common.skc_nulls_node

  #define tw_bind_node		__tw_common.skc_bind_node
  #define tw_refcnt		__tw_common.skc_refcnt

  #define tw_hash			__tw_common.skc_hash

  #define tw_prot			__tw_common.skc_prot

  #define tw_net			__tw_common.skc_net

  #define tw_daddr        	__tw_common.skc_daddr
  #define tw_rcv_saddr    	__tw_common.skc_rcv_saddr

  	int			tw_timeout;

  	volatile unsigned char	tw_substate;

  	unsigned char		tw_rcv_wscale;

  	/* Socket demultiplex comparisons on incoming packets. */

  	/* these three are in inet_sock */

  	__be16			tw_sport;

  	__be16			tw_dport;

  	__u16			tw_num;

  	kmemcheck_bitfield_begin(flags);

  	/* And these are ours. */

  	unsigned int		tw_ipv6only     : 1,
  				tw_transparent  : 1,

  				tw_pad		: 6,	/* 6 bits hole */
  				tw_tos		: 8,

  				tw_ipv6_offset  : 16;

  	kmemcheck_bitfield_end(flags);

  	unsigned long		tw_ttd;
  	struct inet_bind_bucket	*tw_tb;
  	struct hlist_node	tw_death_node;
  };

  #define tw_tclass tw_tos

  static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
  				      struct hlist_nulls_head *list)

  {

  	hlist_nulls_add_head_rcu(&tw->tw_node, list);

  }
  
  static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
  					   struct hlist_head *list)
  {
  	hlist_add_head(&tw->tw_bind_node, list);
  }
  
  static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
  {

  	return !hlist_unhashed(&tw->tw_death_node);

  }
  
  static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
  {
  	tw->tw_death_node.pprev = NULL;
  }
  
  static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
  {
  	__hlist_del(&tw->tw_death_node);
  	inet_twsk_dead_node_init(tw);
  }
  
  static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
  {
  	if (inet_twsk_dead_hashed(tw)) {
  		__inet_twsk_del_dead_node(tw);
  		return 1;
  	}
  	return 0;
  }
  
  #define inet_twsk_for_each(tw, node, head) \

  	hlist_nulls_for_each_entry(tw, node, head, tw_node)

  
  #define inet_twsk_for_each_inmate(tw, node, jail) \
  	hlist_for_each_entry(tw, node, jail, tw_death_node)
  
  #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
  	hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
  
  static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
  {
  	return (struct inet_timewait_sock *)sk;
  }

  static inline __be32 sk_rcv_saddr(const struct sock *sk)

  {

  /* both inet_sk() and inet_twsk() store rcv_saddr in skc_rcv_saddr */
  	return sk->__sk_common.skc_rcv_saddr;

  }

  extern void inet_twsk_put(struct inet_timewait_sock *tw);

  extern int inet_twsk_unhash(struct inet_timewait_sock *tw);

  extern int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
  				 struct inet_hashinfo *hashinfo);

  extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
  						  const int state);

  extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
  				  struct sock *sk,
  				  struct inet_hashinfo *hashinfo);

  
  extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
  			       struct inet_timewait_death_row *twdr,
  			       const int timeo, const int timewait_len);
  extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
  				 struct inet_timewait_death_row *twdr);

  extern void inet_twsk_purge(struct inet_hashinfo *hashinfo,

  			    struct inet_timewait_death_row *twdr, int family);

  static inline
  struct net *twsk_net(const struct inet_timewait_sock *twsk)
  {

  	return read_pnet(&twsk->tw_net);

  }
  
  static inline

  void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)

  {

  	write_pnet(&twsk->tw_net, net);

  }

  #endif	/* _INET_TIMEWAIT_SOCK_ */