/*
   * NET		Generic infrastructure for INET connection oriented protocols.
   *
   *		Definitions for inet_connection_sock 
   *
   * Authors:	Many people, see the TCP sources
   *
   * 		From code originally in TCP
   *
   *		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_CONNECTION_SOCK_H
  #define _INET_CONNECTION_SOCK_H

  #include <linux/compiler.h>

  #include <linux/string.h>

  #include <linux/timer.h>

  #include <linux/poll.h>

  
  #include <net/inet_sock.h>

  #include <net/request_sock.h>

  #define INET_CSK_DEBUG 1
  
  /* Cancel timers, when they are not required. */
  #undef INET_CSK_CLEAR_TIMERS

  struct inet_bind_bucket;

  struct tcp_congestion_ops;

  /*
   * Pointers to address related TCP functions
   * (i.e. things that depend on the address family)
   */
  struct inet_connection_sock_af_ops {

  	int	    (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl);

  	void	    (*send_check)(struct sock *sk, struct sk_buff *skb);

  	int	    (*rebuild_header)(struct sock *sk);

  	void	    (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);

  	int	    (*conn_request)(struct sock *sk, struct sk_buff *skb);

  	struct sock *(*syn_recv_sock)(const struct sock *sk, struct sk_buff *skb,

  				      struct request_sock *req,

  				      struct dst_entry *dst,
  				      struct request_sock *req_unhash,
  				      bool *own_req);

  	u16	    net_header_len;

  	u16	    net_frag_header_len;

  	u16	    sockaddr_len;

  	int	    (*setsockopt)(struct sock *sk, int level, int optname, 

  				  char __user *optval, unsigned int optlen);

  	int	    (*getsockopt)(struct sock *sk, int level, int optname, 
  				  char __user *optval, int __user *optlen);

  #ifdef CONFIG_COMPAT

  	int	    (*compat_setsockopt)(struct sock *sk,
  				int level, int optname,

  				char __user *optval, unsigned int optlen);

  	int	    (*compat_getsockopt)(struct sock *sk,
  				int level, int optname,
  				char __user *optval, int __user *optlen);

  #endif

  	void	    (*addr2sockaddr)(struct sock *sk, struct sockaddr *);

  	void	    (*mtu_reduced)(struct sock *sk);

  };

  /** inet_connection_sock - INET connection oriented sock
   *
   * @icsk_accept_queue:	   FIFO of established children 
   * @icsk_bind_hash:	   Bind node
   * @icsk_timeout:	   Timeout
   * @icsk_retransmit_timer: Resend (no ack)
   * @icsk_rto:		   Retransmit timeout

   * @icsk_pmtu_cookie	   Last pmtu seen by socket

   * @icsk_ca_ops		   Pluggable congestion control hook

   * @icsk_af_ops		   Operations which are AF_INET{4,6} specific

   * @icsk_ulp_ops	   Pluggable ULP control hook
   * @icsk_ulp_data	   ULP private data

   * @icsk_ca_state:	   Congestion control state

   * @icsk_retransmits:	   Number of unrecovered [RTO] timeouts
   * @icsk_pending:	   Scheduled timer event
   * @icsk_backoff:	   Backoff
   * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries

   * @icsk_probes_out:	   unanswered 0 window probes

   * @icsk_ext_hdr_len:	   Network protocol overhead (IP/IPv6 options)

   * @icsk_ack:		   Delayed ACK control data

   * @icsk_mtup;		   MTU probing control data

   */
  struct inet_connection_sock {
  	/* inet_sock has to be the first member! */
  	struct inet_sock	  icsk_inet;
  	struct request_sock_queue icsk_accept_queue;
  	struct inet_bind_bucket	  *icsk_bind_hash;
  	unsigned long		  icsk_timeout;
   	struct timer_list	  icsk_retransmit_timer;
   	struct timer_list	  icsk_delack_timer;
  	__u32			  icsk_rto;

  	__u32			  icsk_pmtu_cookie;

  	const struct tcp_congestion_ops *icsk_ca_ops;
  	const struct inet_connection_sock_af_ops *icsk_af_ops;

  	const struct tcp_ulp_ops  *icsk_ulp_ops;
  	void			  *icsk_ulp_data;

  	unsigned int		  (*icsk_sync_mss)(struct sock *sk, u32 pmtu);

  	__u8			  icsk_ca_state:6,
  				  icsk_ca_setsockopt:1,

  				  icsk_ca_dst_locked:1;

  	__u8			  icsk_retransmits;
  	__u8			  icsk_pending;
  	__u8			  icsk_backoff;
  	__u8			  icsk_syn_retries;

  	__u8			  icsk_probes_out;

  	__u16			  icsk_ext_hdr_len;

  	struct {
  		__u8		  pending;	 /* ACK is pending			   */
  		__u8		  quick;	 /* Scheduled number of quick acks	   */
  		__u8		  pingpong;	 /* The session is interactive		   */
  		__u8		  blocked;	 /* Delayed ACK was blocked by socket lock */
  		__u32		  ato;		 /* Predicted tick of soft clock	   */
  		unsigned long	  timeout;	 /* Currently scheduled timeout		   */
  		__u32		  lrcvtime;	 /* timestamp of last received data packet */
  		__u16		  last_seg_size; /* Size of last incoming segment	   */
  		__u16		  rcv_mss;	 /* MSS used for delayed ACK decisions	   */ 
  	} icsk_ack;

  	struct {
  		int		  enabled;
  
  		/* Range of MTUs to search */
  		int		  search_high;
  		int		  search_low;
  
  		/* Information on the current probe. */
  		int		  probe_size;

  
  		u32		  probe_timestamp;

  	} icsk_mtup;

  	u32			  icsk_user_timeout;

  	u64			  icsk_ca_priv[88 / sizeof(u64)];
  #define ICSK_CA_PRIV_SIZE      (11 * sizeof(u64))

  };

  #define ICSK_TIME_RETRANS	1	/* Retransmit timer */
  #define ICSK_TIME_DACK		2	/* Delayed ack timer */
  #define ICSK_TIME_PROBE0	3	/* Zero window probe timer */

  #define ICSK_TIME_EARLY_RETRANS 4	/* Early retransmit timer */
  #define ICSK_TIME_LOSS_PROBE	5	/* Tail loss probe timer */

  #define ICSK_TIME_REO_TIMEOUT	6	/* Reordering timer */

  static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
  {
  	return (struct inet_connection_sock *)sk;
  }

  static inline void *inet_csk_ca(const struct sock *sk)
  {
  	return (void *)inet_csk(sk)->icsk_ca_priv;
  }

  struct sock *inet_csk_clone_lock(const struct sock *sk,
  				 const struct request_sock *req,
  				 const gfp_t priority);

  enum inet_csk_ack_state_t {
  	ICSK_ACK_SCHED	= 1,
  	ICSK_ACK_TIMER  = 2,

  	ICSK_ACK_PUSHED = 4,
  	ICSK_ACK_PUSHED2 = 8

  };

  void inet_csk_init_xmit_timers(struct sock *sk,
  			       void (*retransmit_handler)(unsigned long),
  			       void (*delack_handler)(unsigned long),
  			       void (*keepalive_handler)(unsigned long));
  void inet_csk_clear_xmit_timers(struct sock *sk);

  static inline void inet_csk_schedule_ack(struct sock *sk)
  {
  	inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
  }
  
  static inline int inet_csk_ack_scheduled(const struct sock *sk)
  {
  	return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
  }
  
  static inline void inet_csk_delack_init(struct sock *sk)
  {
  	memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
  }

  void inet_csk_delete_keepalive_timer(struct sock *sk);
  void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);

  
  #ifdef INET_CSK_DEBUG
  extern const char inet_csk_timer_bug_msg[];
  #endif
  
  static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
  {
  	struct inet_connection_sock *icsk = inet_csk(sk);
  	
  	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
  		icsk->icsk_pending = 0;
  #ifdef INET_CSK_CLEAR_TIMERS
  		sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
  #endif
  	} else if (what == ICSK_TIME_DACK) {
  		icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
  #ifdef INET_CSK_CLEAR_TIMERS
  		sk_stop_timer(sk, &icsk->icsk_delack_timer);
  #endif
  	}
  #ifdef INET_CSK_DEBUG
  	else {

  		pr_debug("%s", inet_csk_timer_bug_msg);

  	}
  #endif
  }
  
  /*
   *	Reset the retransmission timer
   */
  static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
  					     unsigned long when,
  					     const unsigned long max_when)
  {
  	struct inet_connection_sock *icsk = inet_csk(sk);
  
  	if (when > max_when) {
  #ifdef INET_CSK_DEBUG
  		pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p
  ",
  			 sk, what, when, current_text_addr());
  #endif
  		when = max_when;
  	}

  	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||

  	    what == ICSK_TIME_EARLY_RETRANS || what == ICSK_TIME_LOSS_PROBE ||
  	    what == ICSK_TIME_REO_TIMEOUT) {

  		icsk->icsk_pending = what;
  		icsk->icsk_timeout = jiffies + when;
  		sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
  	} else if (what == ICSK_TIME_DACK) {
  		icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
  		icsk->icsk_ack.timeout = jiffies + when;
  		sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
  	}
  #ifdef INET_CSK_DEBUG
  	else {

  		pr_debug("%s", inet_csk_timer_bug_msg);

  	}
  #endif
  }

  static inline unsigned long
  inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
  		     unsigned long max_when)
  {
          u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
  
          return (unsigned long)min_t(u64, when, max_when);
  }

  struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern);

  int inet_csk_get_port(struct sock *sk, unsigned short snum);

  struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,

  				     const struct request_sock *req);

  struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
  					    struct sock *newsk,

  					    const struct request_sock *req);

  struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
  				      struct request_sock *req,
  				      struct sock *child);

  void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
  				   unsigned long timeout);

  struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
  					 struct request_sock *req,
  					 bool own_req);

  static inline void inet_csk_reqsk_queue_added(struct sock *sk)

  {

  	reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);

  }
  
  static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
  {
  	return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
  }

  static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
  {

  	return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;

  }

  void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);

  void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);

  void inet_csk_destroy_sock(struct sock *sk);
  void inet_csk_prepare_forced_close(struct sock *sk);

  
  /*
   * LISTEN is a special case for poll..
   */
  static inline unsigned int inet_csk_listen_poll(const struct sock *sk)
  {
  	return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
  			(POLLIN | POLLRDNORM) : 0;
  }

  int inet_csk_listen_start(struct sock *sk, int backlog);

  void inet_csk_listen_stop(struct sock *sk);

  void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);

  int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
  			       char __user *optval, int __user *optlen);
  int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
  			       char __user *optval, unsigned int optlen);

  struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);

  #endif /* _INET_CONNECTION_SOCK_H */