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/*
 * linux/include/linux/sunrpc/svc.h
 *
 * RPC server declarations.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */



#ifndef SUNRPC_SVC_H
#define SUNRPC_SVC_H

#include <linux/in.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/wait.h>
#include <linux/mm.h>

/*
 * RPC service.
 *
 * An RPC service is a ``daemon,'' possibly multithreaded, which
 * receives and processes incoming RPC messages.
 * It has one or more transport sockets associated with it, and maintains
 * a list of idle threads waiting for input.
 *
 * We currently do not support more than one RPC program per daemon.
 */

struct svc_serv {
        struct list_head        sv_threads;     /* idle server threads */
        struct list_head        sv_sockets;     /* pending sockets */
        struct svc_program *    sv_program;     /* RPC program */
        struct svc_stat *       sv_stats;       /* RPC statistics */
        spinlock_t              sv_lock;
        unsigned int            sv_nrthreads;   /* # of server threads */
        unsigned int            sv_bufsz;       /* datagram buffer size */
        unsigned int            sv_xdrsize;     /* XDR buffer size */

        struct list_head        sv_permsocks;   /* all permanent sockets */
        struct list_head        sv_tempsocks;   /* all temporary sockets */
        int                     sv_tmpcnt;      /* count of temporary sockets */

        char *                  sv_name;        /* service name */
};

/*
 * Maximum payload size supported by a kernel RPC server.
 * This is use to determine the max number of pages nfsd is
 * willing to return in a single READ operation.
 */

#define RPCSVC_MAXPAYLOAD       (64*1024u)

/*
 * RPC Requsts and replies are stored in one or more pages.
 * We maintain an array of pages for each server thread.
 * Requests are copied into these pages as they arrive.  Remaining
 * pages are available to write the reply into.
 *
 * Pages are sent using ->sendpage so each server thread needs to
 * allocate more to replace those used in sending.  To help keep track
 * of these pages we have a receive list where all pages initialy live,
 * and a send list where pages are moved to when there are to be part
 * of a reply.
 *
 * We use xdr_buf for holding responses as it fits well with NFS
 * read responses (that have a header, and some data pages, and possibly
 * a tail) and means we can share some client side routines.
 *
 * The xdr_buf.head iovec always points to the first page in the rq_*pages
 * list.  The xdr_buf.pages pointer points to the second page on that
 * list.  xdr_buf.tail points to the end of the first page.
 * This assumes that the non-page part of an rpc reply will fit
 * in a page - NFSd ensures this.  lockd also has no trouble.
 *
 * Each request/reply pair can have at most one "payload", plus two pages,
 * one for the request, and one for the reply.
 */

#define RPCSVC_MAXPAGES         ((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE + 2)

static inline u32 svc_getu32(struct iovec *iov)
{
        u32 val, *vp;
        vp = iov->iov_base;
        val = *vp++;
        iov->iov_base = (void*)vp;
        iov->iov_len -= sizeof(u32);
        return val;
}
static inline void svc_putu32(struct iovec *iov, u32 val)
{
        u32 *vp = iov->iov_base + iov->iov_len;
        *vp = val;
        iov->iov_len += sizeof(u32);
}

       
/*
 * The context of a single thread, including the request currently being
 * processed.
 * NOTE: First two items must be prev/next.
 */

struct svc_rqst {
        struct list_head        rq_list;        /* idle list */
        struct svc_sock *       rq_sock;        /* socket */
        struct sockaddr_in      rq_addr;        /* peer address */
        int                     rq_addrlen;

        struct svc_serv *       rq_server;      /* RPC service definition */
        struct svc_procedure *  rq_procinfo;    /* procedure info */
        struct auth_ops *       rq_authop;      /* authentication flavour */
        struct svc_cred         rq_cred;        /* auth info */
        struct sk_buff *        rq_skbuff;      /* fast recv inet buffer */
        struct svc_deferred_req*rq_deferred;    /* deferred request we are replaying */

        struct xdr_buf          rq_arg;
        struct xdr_buf          rq_res;
        struct page *           rq_argpages[RPCSVC_MAXPAGES];
        struct page *           rq_respages[RPCSVC_MAXPAGES];
        int                     rq_restailpage;
        short                   rq_argused;     /* pages used for argument */
        short                   rq_arghi;       /* pages available in argument page list */
        short                   rq_resused;     /* pages used for result */

        u32                     rq_xid;         /* transmission id */
        u32                     rq_prog;        /* program number */
        u32                     rq_vers;        /* program version */
        u32                     rq_proc;        /* procedure number */
        u32                     rq_prot;        /* IP protocol */
        unsigned short
                                rq_secure  : 1; /* secure port */


        __u32                   rq_daddr;       /* dest addr of request - reply from here */

        void *                  rq_argp;        /* decoded arguments */
        void *                  rq_resp;        /* xdr'd results */

        int                     rq_reserved;    /* space on socket outq
                                                 * reserved for this request
                                                 */


        struct cache_req        rq_chandle;     /* handle passed to caches for
                                                 * request delaying
                                                 */

        /* Catering to nfsd */
        struct auth_domain *    rq_client;      /* RPC peer info */
        struct svc_cacherep *   rq_cacherep;    /* cache info */
        struct knfsd_fh *       rq_reffh;       /* Referrence filehandle, used to
                                                 * determine what device number
                                                 * to report (real or virtual)
                                                 */


        wait_queue_head_t       rq_wait;        /* synchronization */
};

/*
 * Check buffer bounds after decoding arguments
 */

static inline int
xdr_argsize_check(struct svc_rqst *rqstp, u32 *p)
{
        char *cp = (char *)p;
        struct iovec *vec = &rqstp->rq_arg.head[0];
        return cp - (char*)vec->iov_base <= vec->iov_len;
}

static inline int
xdr_ressize_check(struct svc_rqst *rqstp, u32 *p)
{
        struct iovec *vec = &rqstp->rq_res.head[0];
        char *cp = (char*)p;

        vec->iov_len = cp - (char*)vec->iov_base;

        return vec->iov_len <= PAGE_SIZE;
}

static inline int svc_take_page(struct svc_rqst *rqstp)
{
        if (rqstp->rq_arghi <= rqstp->rq_argused)
                return -ENOMEM;
        rqstp->rq_arghi--;
        rqstp->rq_respages[rqstp->rq_resused] =
                rqstp->rq_argpages[rqstp->rq_arghi];
        rqstp->rq_resused++;
        return 0;
}

static inline void svc_pushback_allpages(struct svc_rqst *rqstp)
{
        while (rqstp->rq_resused) {
                if (rqstp->rq_respages[--rqstp->rq_resused] == NULL)
                        continue;
                rqstp->rq_argpages[rqstp->rq_arghi++] =
                        rqstp->rq_respages[rqstp->rq_resused];
                rqstp->rq_respages[rqstp->rq_resused] = NULL;
        }
}

static inline void svc_pushback_unused_pages(struct svc_rqst *rqstp)
{
        while (rqstp->rq_resused &&
               rqstp->rq_res.pages != &rqstp->rq_respages[rqstp->rq_resused]) {

                if (rqstp->rq_respages[--rqstp->rq_resused] != NULL) {
                        rqstp->rq_argpages[rqstp->rq_arghi++] =
                                rqstp->rq_respages[rqstp->rq_resused];
                        rqstp->rq_respages[rqstp->rq_resused] = NULL;
                }
        }
}

static inline void svc_free_allpages(struct svc_rqst *rqstp)
{
        while (rqstp->rq_resused) {
                if (rqstp->rq_respages[--rqstp->rq_resused] == NULL)
                        continue;
                put_page(rqstp->rq_respages[rqstp->rq_resused]);
                rqstp->rq_respages[rqstp->rq_resused] = NULL;
        }
}

struct svc_deferred_req {
        u32                     prot;   /* protocol (UDP or TCP) */
        struct sockaddr_in      addr;
        struct svc_sock         *svsk;  /* where reply must go */
        struct cache_deferred_req handle;
        int                     argslen;
        u32                     args[0];
};

/*
 * RPC program
 */

struct svc_program {
        u32                     pg_prog;        /* program number */
        unsigned int            pg_lovers;      /* lowest version */
        unsigned int            pg_hivers;      /* lowest version */
        unsigned int            pg_nvers;       /* number of versions */
        struct svc_version **   pg_vers;        /* version array */
        char *                  pg_name;        /* service name */
        char *                  pg_class;       /* class name: services sharing authentication */
        struct svc_stat *       pg_stats;       /* rpc statistics */
};

/*
 * RPC program version
 */

struct svc_version {
        u32                     vs_vers;        /* version number */
        u32                     vs_nproc;       /* number of procedures */
        struct svc_procedure *  vs_proc;        /* per-procedure info */
        u32                     vs_xdrsize;     /* xdrsize needed for this version */

        /* Override dispatch function (e.g. when caching replies).
         * A return value of 0 means drop the request.
         * vs_dispatch == NULL means use default dispatcher.
         */

        int                     (*vs_dispatch)(struct svc_rqst *, u32 *);
};

/*
 * RPC procedure info
 */

typedef int     (*svc_procfunc)(struct svc_rqst *, void *argp, void *resp);
struct svc_procedure {
        svc_procfunc            pc_func;        /* process the request */
        kxdrproc_t              pc_decode;      /* XDR decode args */
        kxdrproc_t              pc_encode;      /* XDR encode result */
        kxdrproc_t              pc_release;     /* XDR free result */
        unsigned int            pc_argsize;     /* argument struct size */
        unsigned int            pc_ressize;     /* result struct size */
        unsigned int            pc_count;       /* call count */
        unsigned int            pc_cachetype;   /* cache info (NFS) */
        unsigned int            pc_xdrressize;  /* maximum size of XDR reply */
};

/*
 * This is the RPC server thread function prototype
 */

typedef void            (*svc_thread_fn)(struct svc_rqst *);

/*
 * Function prototypes.
 */

struct svc_serv *  svc_create(struct svc_program *, unsigned int);
int                svc_create_thread(svc_thread_fn, struct svc_serv *);
void               svc_exit_thread(struct svc_rqst *);
void               svc_destroy(struct svc_serv *);
int                svc_process(struct svc_serv *, struct svc_rqst *);
int                svc_register(struct svc_serv *, int, unsigned short);
void               svc_wake_up(struct svc_serv *);
void               svc_reserve(struct svc_rqst *rqstp, int space);

#endif /* SUNRPC_SVC_H */