/*

   *  linux/include/linux/sunrpc/xprt.h

   *
   *  Declarations for the RPC transport interface.
   *
   *  Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   */
  
  #ifndef _LINUX_SUNRPC_XPRT_H
  #define _LINUX_SUNRPC_XPRT_H
  
  #include <linux/uio.h>
  #include <linux/socket.h>
  #include <linux/in.h>

  #include <linux/ktime.h>

  #include <linux/sunrpc/sched.h>
  #include <linux/sunrpc/xdr.h>

  #include <linux/sunrpc/msg_prot.h>

  #ifdef __KERNEL__

  #define RPC_MIN_SLOT_TABLE	(2U)
  #define RPC_DEF_SLOT_TABLE	(16U)
  #define RPC_MAX_SLOT_TABLE	(128U)

  #define RPC_MAX_SLOT_TABLE_LIMIT	(65536U)

  /*

   * This describes a timeout strategy
   */
  struct rpc_timeout {
  	unsigned long		to_initval,		/* initial timeout */
  				to_maxval,		/* max timeout */
  				to_increment;		/* if !exponential */
  	unsigned int		to_retries;		/* max # of retries */
  	unsigned char		to_exponential;
  };

  enum rpc_display_format_t {
  	RPC_DISPLAY_ADDR = 0,
  	RPC_DISPLAY_PORT,
  	RPC_DISPLAY_PROTO,

  	RPC_DISPLAY_HEX_ADDR,
  	RPC_DISPLAY_HEX_PORT,

  	RPC_DISPLAY_NETID,

  	RPC_DISPLAY_MAX,
  };

  struct rpc_task;
  struct rpc_xprt;

  struct seq_file;

  /*
   * This describes a complete RPC request
   */
  struct rpc_rqst {
  	/*
  	 * This is the user-visible part
  	 */
  	struct rpc_xprt *	rq_xprt;		/* RPC client */
  	struct xdr_buf		rq_snd_buf;		/* send buffer */
  	struct xdr_buf		rq_rcv_buf;		/* recv buffer */
  
  	/*
  	 * This is the private part
  	 */
  	struct rpc_task *	rq_task;	/* RPC task data */

  	struct rpc_cred *	rq_cred;	/* Bound cred */

  	__be32			rq_xid;		/* request XID */

  	int			rq_cong;	/* has incremented xprt->cong */

  	u32			rq_seqno;	/* gss seq no. used on req. */

  	int			rq_enc_pages_num;
  	struct page		**rq_enc_pages;	/* scratch pages for use by
  						   gss privacy code */
  	void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */

  	struct list_head	rq_list;

  	__u32 *			rq_buffer;	/* XDR encode buffer */

  	size_t			rq_callsize,

  				rq_rcvsize;

  	size_t			rq_xmit_bytes_sent;	/* total bytes sent */
  	size_t			rq_reply_bytes_recvd;	/* total reply bytes */
  							/* received */

  	struct xdr_buf		rq_private_buf;		/* The receive buffer
  							 * used in the softirq.
  							 */
  	unsigned long		rq_majortimeo;	/* major timeout alarm */
  	unsigned long		rq_timeout;	/* Current timeout value */

  	ktime_t			rq_rtt;		/* round-trip time */

  	unsigned int		rq_retries;	/* # of retries */

  	unsigned int		rq_connect_cookie;
  						/* A cookie used to track the
  						   state of the transport
  						   connection */

  	
  	/*
  	 * Partial send handling
  	 */

  	u32			rq_bytes_sent;	/* Bytes we have sent */

  	ktime_t			rq_xtime;	/* transmit time stamp */

  	int			rq_ntrans;

  #if defined(CONFIG_SUNRPC_BACKCHANNEL)

  	struct list_head	rq_bc_list;	/* Callback service list */
  	unsigned long		rq_bc_pa_state;	/* Backchannel prealloc state */
  	struct list_head	rq_bc_pa_list;	/* Backchannel prealloc list */

  #endif /* CONFIG_SUNRPC_BACKCHANEL */

  };
  #define rq_svec			rq_snd_buf.head
  #define rq_slen			rq_snd_buf.len

  struct rpc_xprt_ops {

  	void		(*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);

  	int		(*reserve_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);

  	void		(*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);

  	void		(*rpcbind)(struct rpc_task *task);

  	void		(*set_port)(struct rpc_xprt *xprt, unsigned short port);

  	void		(*connect)(struct rpc_task *task);

  	void *		(*buf_alloc)(struct rpc_task *task, size_t size);

  	void		(*buf_free)(void *buffer);

  	int		(*send_request)(struct rpc_task *task);

  	void		(*set_retrans_timeout)(struct rpc_task *task);

  	void		(*timer)(struct rpc_task *task);

  	void		(*release_request)(struct rpc_task *task);

  	void		(*close)(struct rpc_xprt *xprt);
  	void		(*destroy)(struct rpc_xprt *xprt);

  	void		(*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);

  };

  /*
   * RPC transport identifiers
   *
   * To preserve compatibility with the historical use of raw IP protocol
   * id's for transport selection, UDP and TCP identifiers are specified
   * with the previous values. No such restriction exists for new transports,
   * except that they may not collide with these values (17 and 6,
   * respectively).
   */
  #define XPRT_TRANSPORT_BC       (1 << 31)
  enum xprt_transports {
  	XPRT_TRANSPORT_UDP	= IPPROTO_UDP,
  	XPRT_TRANSPORT_TCP	= IPPROTO_TCP,
  	XPRT_TRANSPORT_BC_TCP	= IPPROTO_TCP | XPRT_TRANSPORT_BC,

  	XPRT_TRANSPORT_RDMA	= 256,
  	XPRT_TRANSPORT_LOCAL	= 257,

  };

  struct rpc_xprt {

  	atomic_t		count;		/* Reference count */

  	struct rpc_xprt_ops *	ops;		/* transport methods */

  	const struct rpc_timeout *timeout;	/* timeout parms */

  	struct sockaddr_storage	addr;		/* server address */
  	size_t			addrlen;	/* size of server address */

  	int			prot;		/* IP protocol */
  
  	unsigned long		cong;		/* current congestion */
  	unsigned long		cwnd;		/* congestion window */

  	size_t			max_payload;	/* largest RPC payload size,
  						   in bytes */

  	unsigned int		tsh_size;	/* size of transport specific
  						   header */

  	struct rpc_wait_queue	binding;	/* requests waiting on rpcbind */

  	struct rpc_wait_queue	sending;	/* requests waiting to send */

  	struct rpc_wait_queue	pending;	/* requests in flight */
  	struct rpc_wait_queue	backlog;	/* waiting for slot */
  	struct list_head	free;		/* free slots */

  	unsigned int		max_reqs;	/* max number of slots */
  	unsigned int		min_reqs;	/* min number of slots */
  	atomic_t		num_reqs;	/* total slots */

  	unsigned long		state;		/* transport state */

  	unsigned char		shutdown   : 1,	/* being shut down */

  				resvport   : 1; /* use a reserved port */

  	unsigned int		bind_index;	/* bind function index */

  
  	/*

  	 * Connection of transports

  	 */

  	unsigned long		bind_timeout,

  				reestablish_timeout;

  	unsigned int		connect_cookie;	/* A cookie that gets bumped
  						   every time the transport
  						   is reconnected */

  	/*

  	 * Disconnection of idle transports

  	 */
  	struct work_struct	task_cleanup;
  	struct timer_list	timer;

  	unsigned long		last_used,
  				idle_timeout;

  
  	/*
  	 * Send stuff
  	 */

  	spinlock_t		transport_lock;	/* lock transport info */

  	spinlock_t		reserve_lock;	/* lock slot table */

  	u32			xid;		/* Next XID value to use */

  	struct rpc_task *	snd_task;	/* Task blocked in send */

  	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */

  #if defined(CONFIG_SUNRPC_BACKCHANNEL)

  	struct svc_serv		*bc_serv;       /* The RPC service which will */
  						/* process the callback */

  	unsigned int		bc_alloc_count;	/* Total number of preallocs */

  	spinlock_t		bc_pa_lock;	/* Protects the preallocated
  						 * items */
  	struct list_head	bc_pa_list;	/* List of preallocated
  						 * backchannel rpc_rqst's */

  #endif /* CONFIG_SUNRPC_BACKCHANNEL */

  	struct list_head	recv;

  	struct {
  		unsigned long		bind_count,	/* total number of binds */
  					connect_count,	/* total number of connects */
  					connect_start,	/* connect start timestamp */
  					connect_time,	/* jiffies waiting for connect */
  					sends,		/* how many complete requests */
  					recvs,		/* how many complete requests */
  					bad_xids;	/* lookup_rqst didn't find XID */
  
  		unsigned long long	req_u,		/* average requests on the wire */
  					bklog_u;	/* backlog queue utilization */
  	} stat;

  	struct net		*xprt_net;

  	const char		*address_strings[RPC_DISPLAY_MAX];

  };

  #if defined(CONFIG_SUNRPC_BACKCHANNEL)

  /*
   * Backchannel flags
   */
  #define	RPC_BC_PA_IN_USE	0x0001		/* Preallocated backchannel */
  						/* buffer in use */

  #endif /* CONFIG_SUNRPC_BACKCHANNEL */

  #if defined(CONFIG_SUNRPC_BACKCHANNEL)

  static inline int bc_prealloc(struct rpc_rqst *req)
  {
  	return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
  }
  #else
  static inline int bc_prealloc(struct rpc_rqst *req)
  {
  	return 0;
  }

  #endif /* CONFIG_SUNRPC_BACKCHANNEL */

  struct xprt_create {

  	int			ident;		/* XPRT_TRANSPORT identifier */

  	struct net *		net;

  	struct sockaddr *	srcaddr;	/* optional local address */

  	struct sockaddr *	dstaddr;	/* remote peer address */
  	size_t			addrlen;

  	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */

  };

  struct xprt_class {
  	struct list_head	list;

  	int			ident;		/* XPRT_TRANSPORT identifier */

  	struct rpc_xprt *	(*setup)(struct xprt_create *);

  	struct module		*owner;
  	char			name[32];
  };

  /*

   * Generic internal transport functions
   */

  struct rpc_xprt		*xprt_create_transport(struct xprt_create *args);

  void			xprt_connect(struct rpc_task *task);
  void			xprt_reserve(struct rpc_task *task);

  int			xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
  int			xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);

  int			xprt_prepare_transmit(struct rpc_task *task);
  void			xprt_transmit(struct rpc_task *task);

  void			xprt_end_transmit(struct rpc_task *task);

  int			xprt_adjust_timeout(struct rpc_rqst *req);

  void			xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
  void			xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);

  void			xprt_release(struct rpc_task *task);

  struct rpc_xprt *	xprt_get(struct rpc_xprt *xprt);
  void			xprt_put(struct rpc_xprt *xprt);

  struct rpc_xprt *	xprt_alloc(struct net *net, size_t size,
  				unsigned int num_prealloc,
  				unsigned int max_req);

  void			xprt_free(struct rpc_xprt *);

  static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *p)

  {
  	return p + xprt->tsh_size;
  }

  /*
   * Transport switch helper functions
   */

  int			xprt_register_transport(struct xprt_class *type);
  int			xprt_unregister_transport(struct xprt_class *type);

  int			xprt_load_transport(const char *);

  void			xprt_set_retrans_timeout_def(struct rpc_task *task);
  void			xprt_set_retrans_timeout_rtt(struct rpc_task *task);

  void			xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);

  void			xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action);

  void			xprt_write_space(struct rpc_xprt *xprt);

  void			xprt_adjust_cwnd(struct rpc_task *task, int result);

  struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);

  void			xprt_complete_rqst(struct rpc_task *task, int copied);

  void			xprt_release_rqst_cong(struct rpc_task *task);

  void			xprt_disconnect_done(struct rpc_xprt *xprt);

  void			xprt_force_disconnect(struct rpc_xprt *xprt);

  void			xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);

  
  /*

   * Reserved bit positions in xprt->state
   */
  #define XPRT_LOCKED		(0)
  #define XPRT_CONNECTED		(1)
  #define XPRT_CONNECTING		(2)

  #define XPRT_CLOSE_WAIT		(3)

  #define XPRT_BOUND		(4)

  #define XPRT_BINDING		(5)

  #define XPRT_CLOSING		(6)

  #define XPRT_CONNECTION_ABORT	(7)

  #define XPRT_CONNECTION_CLOSE	(8)

  
  static inline void xprt_set_connected(struct rpc_xprt *xprt)
  {
  	set_bit(XPRT_CONNECTED, &xprt->state);
  }
  
  static inline void xprt_clear_connected(struct rpc_xprt *xprt)
  {
  	clear_bit(XPRT_CONNECTED, &xprt->state);
  }
  
  static inline int xprt_connected(struct rpc_xprt *xprt)
  {
  	return test_bit(XPRT_CONNECTED, &xprt->state);
  }
  
  static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
  {
  	return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
  }
  
  static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
  {
  	return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
  }
  
  static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
  {
  	smp_mb__before_clear_bit();
  	clear_bit(XPRT_CONNECTING, &xprt->state);
  	smp_mb__after_clear_bit();
  }
  
  static inline int xprt_connecting(struct rpc_xprt *xprt)
  {
  	return test_bit(XPRT_CONNECTING, &xprt->state);
  }
  
  static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
  {
  	return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
  }

  static inline void xprt_set_bound(struct rpc_xprt *xprt)
  {
  	test_and_set_bit(XPRT_BOUND, &xprt->state);
  }
  
  static inline int xprt_bound(struct rpc_xprt *xprt)
  {
  	return test_bit(XPRT_BOUND, &xprt->state);
  }
  
  static inline void xprt_clear_bound(struct rpc_xprt *xprt)
  {
  	clear_bit(XPRT_BOUND, &xprt->state);
  }

  static inline void xprt_clear_binding(struct rpc_xprt *xprt)
  {
  	smp_mb__before_clear_bit();
  	clear_bit(XPRT_BINDING, &xprt->state);
  	smp_mb__after_clear_bit();
  }
  
  static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
  {
  	return test_and_set_bit(XPRT_BINDING, &xprt->state);
  }

  #endif /* __KERNEL__*/
  
  #endif /* _LINUX_SUNRPC_XPRT_H */