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

/*
 * The transport code maintains an estimate on the maximum number of out-
 * standing RPC requests, using a smoothed version of the congestion
 * avoidance implemented in 44BSD. This is basically the Van Jacobson
 * congestion algorithm: If a retransmit occurs, the congestion window is
 * halved; otherwise, it is incremented by 1/cwnd when
 *
 *      -       a reply is received and
 *      -       a full number of requests are outstanding and
 *      -       the congestion window hasn't been updated recently.
 *
 * Upper procedures may check whether a request would block waiting for
 * a free RPC slot by using the RPC_CONGESTED() macro.
 *
 * Note: on machines with low memory we should probably use a smaller
 * MAXREQS value: At 32 outstanding reqs with 8 megs of RAM, fragment
 * reassembly will frequently run out of memory.
 */

#define RPC_MAXCONG             (16)
#define RPC_MAXREQS             RPC_MAXCONG
#define RPC_CWNDSCALE           (256)
#define RPC_MAXCWND             (RPC_MAXCONG * RPC_CWNDSCALE)
#define RPC_INITCWND            RPC_CWNDSCALE
#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)

/* Default timeout values */
#define RPC_MAX_UDP_TIMEOUT     (60*HZ)
#define RPC_MAX_TCP_TIMEOUT     (600*HZ)

/*
 * Wait duration for an RPC TCP connection to be established.  Solaris
 * NFS over TCP uses 60 seconds, for example, which is in line with how
 * long a server takes to reboot.
 */

#define RPC_CONNECT_TIMEOUT     (60*HZ)

/*
 * Delay an arbitrary number of seconds before attempting to reconnect
 * after an error.
 */

#define RPC_REESTABLISH_TIMEOUT (15*HZ)

/* RPC call and reply header size as number of 32bit words (verifier
 * size computed separately)
 */

#define RPC_CALLHDRSIZE         6
#define RPC_REPHDRSIZE          4

/*
 * This describes a timeout strategy
 */

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

/*
 * This describes a complete RPC request
 */

struct rpc_rqst {
        /*
         * This is the user-visible part
         */

        struct rpc_xprt *       rq_xprt;                /* RPC client */
        struct rpc_timeout      rq_timeout;             /* timeout parms */
        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 */
        __u32                   rq_xid;         /* request XID */
        struct rpc_rqst *       rq_next;        /* free list */
        int                     rq_cong;        /* has incremented xprt->cong */
        int                     rq_received;    /* receive completed */

        struct list_head        rq_list;

        struct xdr_buf          rq_private_buf;         /* The receive buffer
                                                         * used in the softirq.
                                                         */


        /*
         * For authentication (e.g. auth_des)
         */

        u32                     rq_creddata[2];
       
        /*
         * Partial send handling
         */

       
        u32                     rq_bytes_sent;  /* Bytes we have sent */

        unsigned long           rq_xtime;       /* when transmitted */
        int                     rq_ntimeo;
        int                     rq_ntrans;
};
#define rq_svec                 rq_snd_buf.head
#define rq_slen                 rq_snd_buf.len
#define rq_rvec                 rq_rcv_buf.head
#define rq_rlen                 rq_rcv_buf.len

#define XPRT_LAST_FRAG          (1 << 0)
#define XPRT_COPY_RECM          (1 << 1)
#define XPRT_COPY_XID           (1 << 2)
#define XPRT_COPY_DATA          (1 << 3)

struct rpc_xprt {
        struct socket *         sock;           /* BSD socket layer */
        struct sock *           inet;           /* INET layer */

        struct rpc_timeout      timeout;        /* timeout parms */
        struct sockaddr_in      addr;           /* server address */
        int                     prot;           /* IP protocol */

        unsigned long           cong;           /* current congestion */
        unsigned long           cwnd;           /* congestion window */

        unsigned int            rcvsize,        /* socket receive buffer size */
                                sndsize;        /* socket send buffer size */

        struct rpc_wait_queue   sending;        /* requests waiting to send */
        struct rpc_wait_queue   resend;         /* requests waiting to resend */
        struct rpc_wait_queue   pending;        /* requests in flight */
        struct rpc_wait_queue   backlog;        /* waiting for slot */
        struct rpc_rqst *       free;           /* free slots */
        struct rpc_rqst         slot[RPC_MAXREQS];
        unsigned long           sockstate;      /* Socket state */
        unsigned char           shutdown   : 1, /* being shut down */
                                nocong     : 1, /* no congestion control */
                                resvport   : 1, /* use a reserved port */
                                stream     : 1; /* TCP */

        /*
         * State of TCP reply receive stuff
         */

        u32                     tcp_recm,       /* Fragment header */
                                tcp_xid,        /* Current XID */
                                tcp_reclen,     /* fragment length */
                                tcp_offset;     /* fragment offset */
        unsigned long           tcp_copied,     /* copied to request */
                                tcp_flags;

        /*
         * Send stuff
         */

        spinlock_t              sock_lock;      /* lock socket info */
        spinlock_t              xprt_lock;      /* lock xprt info */
        struct rpc_task *       snd_task;       /* Task blocked in send */

        struct list_head        recv;


        void                    (*old_data_ready)(struct sock *, int);
        void                    (*old_state_change)(struct sock *);
        void                    (*old_write_space)(struct sock *);

        wait_queue_head_t       cong_wait;
};

#ifdef __KERNEL__

struct rpc_xprt *       xprt_create_proto(int proto, struct sockaddr_in *addr,
                                        struct rpc_timeout *toparms);
int                     xprt_destroy(struct rpc_xprt *);
void                    xprt_shutdown(struct rpc_xprt *);
void                    xprt_default_timeout(struct rpc_timeout *, int);
void                    xprt_set_timeout(struct rpc_timeout *, unsigned int,
                                        unsigned long);

void                    xprt_reserve(struct rpc_task *);
int                     xprt_prepare_transmit(struct rpc_task *);
void                    xprt_transmit(struct rpc_task *);
void                    xprt_receive(struct rpc_task *);
int                     xprt_adjust_timeout(struct rpc_timeout *);
void                    xprt_release(struct rpc_task *);
void                    xprt_connect(struct rpc_task *);
int                     xprt_clear_backlog(struct rpc_xprt *);
void                    xprt_sock_setbufsize(struct rpc_xprt *);

#define XPRT_CONNECT    0

#define xprt_connected(xp)              (test_bit(XPRT_CONNECT, &(xp)->sockstate))
#define xprt_set_connected(xp)          (set_bit(XPRT_CONNECT, &(xp)->sockstate))
#define xprt_test_and_set_connected(xp) (test_and_set_bit(XPRT_CONNECT, &(xp)->sockstate))
#define xprt_clear_connected(xp)        (clear_bit(XPRT_CONNECT, &(xp)->sockstate))

#endif /* __KERNEL__*/

#endif /* _LINUX_SUNRPC_XPRT_H */