svc.h

Go to the documentation of this file.

/*
 * linux/include/linux/sunrpc/svc.h
 *
 * RPC server declarations.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <[email protected]>
 */


#ifndef SUNRPC_SVC_H
#define SUNRPC_SVC_H

#include <linux/in.h>
#include <linux/in6.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/wait.h>
#include <linux/mm.h>

/*
 * This is the RPC server thread function prototype
 */
typedef int     (*svc_thread_fn)(void *);

/* statistics for svc_pool structures */
struct svc_pool_stats {
    unsigned long   packets;
    unsigned long   sockets_queued;
    unsigned long   threads_woken;
    unsigned long   threads_timedout;
};

/*
 *
 * RPC service thread pool.
 *
 * Pool of threads and temporary sockets.  Generally there is only
 * a single one of these per RPC service, but on NUMA machines those
 * services that can benefit from it (i.e. nfs but not lockd) will
 * have one pool per NUMA node.  This optimisation reduces cross-
 * node traffic on multi-node NUMA NFS servers.
 */
struct svc_pool {
    unsigned int        sp_id;          /* pool id; also node id on NUMA */
    spinlock_t      sp_lock;    /* protects all fields */
    struct list_head    sp_threads; /* idle server threads */
    struct list_head    sp_sockets; /* pending sockets */
    unsigned int        sp_nrthreads;   /* # of threads in pool */
    struct list_head    sp_all_threads; /* all server threads */
    struct svc_pool_stats   sp_stats;   /* statistics on pool operation */
} ____cacheline_aligned_in_smp;

/*
 * 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 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_maxconn; /* max connections allowed or
                         * '0' causing max to be based
                         * on number of threads. */

    unsigned int        sv_max_payload; /* datagram payload size */
    unsigned int        sv_max_mesg;    /* max_payload + 1 page for overheads */
    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 */
    struct timer_list   sv_temptimer;   /* timer for aging temporary sockets */

    char *          sv_name;    /* service name */

    unsigned int        sv_nrpools; /* number of thread pools */
    struct svc_pool *   sv_pools;   /* array of thread pools */

    void            (*sv_shutdown)(struct svc_serv *serv,
                           struct net *net);
                        /* Callback to use when last thread
                         * exits.
                         */

    struct module *     sv_module;  /* optional module to count when
                         * adding threads */
    svc_thread_fn       sv_function;    /* main function for threads */
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
    struct list_head    sv_cb_list; /* queue for callback requests
                         * that arrive over the same
                         * connection */
    spinlock_t      sv_cb_lock; /* protects the svc_cb_list */
    wait_queue_head_t   sv_cb_waitq;    /* sleep here if there are no
                         * entries in the svc_cb_list */
    struct svc_xprt     *sv_bc_xprt;    /* callback on fore channel */
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
};

/*
 * We use sv_nrthreads as a reference count.  svc_destroy() drops
 * this refcount, so we need to bump it up around operations that
 * change the number of threads.  Horrible, but there it is.
 * Should be called with the BKL held.
 */
static inline void svc_get(struct svc_serv *serv)
{
    serv->sv_nrthreads++;
}

/*
 * 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.
 *
 * These happen to all be powers of 2, which is not strictly
 * necessary but helps enforce the real limitation, which is
 * that they should be multiples of PAGE_CACHE_SIZE.
 *
 * For UDP transports, a block plus NFS,RPC, and UDP headers
 * has to fit into the IP datagram limit of 64K.  The largest
 * feasible number for all known page sizes is probably 48K,
 * but we choose 32K here.  This is the same as the historical
 * Linux limit; someone who cares more about NFS/UDP performance
 * can test a larger number.
 *
 * For TCP transports we have more freedom.  A size of 1MB is
 * chosen to match the client limit.  Other OSes are known to
 * have larger limits, but those numbers are probably beyond
 * the point of diminishing returns.
 */
#define RPCSVC_MAXPAYLOAD   (1*1024*1024u)
#define RPCSVC_MAXPAYLOAD_TCP   RPCSVC_MAXPAYLOAD
#define RPCSVC_MAXPAYLOAD_UDP   (32*1024u)

extern u32 svc_max_payload(const struct svc_rqst *rqstp);

/*
 * 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 kvec 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.
 * We using ->sendfile to return read data, we might need one extra page
 * if the request is not page-aligned.  So add another '1'.
 */
#define RPCSVC_MAXPAGES     ((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE \
                + 2 + 1)

static inline u32 svc_getnl(struct kvec *iov)
{
    __be32 val, *vp;
    vp = iov->iov_base;
    val = *vp++;
    iov->iov_base = (void*)vp;
    iov->iov_len -= sizeof(__be32);
    return ntohl(val);
}

static inline void svc_putnl(struct kvec *iov, u32 val)
{
    __be32 *vp = iov->iov_base + iov->iov_len;
    *vp = htonl(val);
    iov->iov_len += sizeof(__be32);
}

static inline __be32 svc_getu32(struct kvec *iov)
{
    __be32 val, *vp;
    vp = iov->iov_base;
    val = *vp++;
    iov->iov_base = (void*)vp;
    iov->iov_len -= sizeof(__be32);
    return val;
}

static inline void svc_ungetu32(struct kvec *iov)
{
    __be32 *vp = (__be32 *)iov->iov_base;
    iov->iov_base = (void *)(vp - 1);
    iov->iov_len += sizeof(*vp);
}

static inline void svc_putu32(struct kvec *iov, __be32 val)
{
    __be32 *vp = iov->iov_base + iov->iov_len;
    *vp = val;
    iov->iov_len += sizeof(__be32);
}

/*
 * The context of a single thread, including the request currently being
 * processed.
 */
struct svc_rqst {
    struct list_head    rq_list;    /* idle list */
    struct list_head    rq_all;     /* all threads list */
    struct svc_xprt *   rq_xprt;    /* transport ptr */

    struct sockaddr_storage rq_addr;    /* peer address */
    size_t          rq_addrlen;
    struct sockaddr_storage rq_daddr;   /* dest addr of request
                         *  - reply from here */
    size_t          rq_daddrlen;

    struct svc_serv *   rq_server;  /* RPC service definition */
    struct svc_pool *   rq_pool;    /* thread pool */
    struct svc_procedure *  rq_procinfo;    /* procedure info */
    struct auth_ops *   rq_authop;  /* authentication flavour */
    struct svc_cred     rq_cred;    /* auth info */
    void *          rq_xprt_ctxt;   /* transport specific context ptr */
    struct svc_deferred_req*rq_deferred;    /* deferred request we are replaying */
    int         rq_usedeferral; /* use deferral */

    size_t          rq_xprt_hlen;   /* xprt header len */
    struct xdr_buf      rq_arg;
    struct xdr_buf      rq_res;
    struct page *       rq_pages[RPCSVC_MAXPAGES];
    struct page *       *rq_respages;   /* points into rq_pages */
    int         rq_resused; /* number of pages used for result */

    struct kvec     rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */

    __be32          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 */

    void *          rq_argp;    /* decoded arguments */
    void *          rq_resp;    /* xdr'd results */
    void *          rq_auth_data;   /* flavor-specific data */

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

    struct cache_req    rq_chandle; /* handle passed to caches for 
                         * request delaying 
                         */
    bool            rq_dropme;
    /* Catering to nfsd */
    struct auth_domain *    rq_client;  /* RPC peer info */
    struct auth_domain *    rq_gssclient;   /* "gss/"-style peer info */
    int         rq_cachetype;
    struct svc_cacherep *   rq_cacherep;    /* cache info */
    int         rq_splice_ok;   /* turned off in gss privacy
                         * to prevent encrypting page
                         * cache pages */
    wait_queue_head_t   rq_wait;    /* synchronization */
    struct task_struct  *rq_task;   /* service thread */
};

#define SVC_NET(svc_rqst)   (svc_rqst->rq_xprt->xpt_net)

/*
 * Rigorous type checking on sockaddr type conversions
 */
static inline struct sockaddr_in *svc_addr_in(const struct svc_rqst *rqst)
{
    return (struct sockaddr_in *) &rqst->rq_addr;
}

static inline struct sockaddr_in6 *svc_addr_in6(const struct svc_rqst *rqst)
{
    return (struct sockaddr_in6 *) &rqst->rq_addr;
}

static inline struct sockaddr *svc_addr(const struct svc_rqst *rqst)
{
    return (struct sockaddr *) &rqst->rq_addr;
}

static inline struct sockaddr_in *svc_daddr_in(const struct svc_rqst *rqst)
{
    return (struct sockaddr_in *) &rqst->rq_daddr;
}

static inline struct sockaddr_in6 *svc_daddr_in6(const struct svc_rqst *rqst)
{
    return (struct sockaddr_in6 *) &rqst->rq_daddr;
}

static inline struct sockaddr *svc_daddr(const struct svc_rqst *rqst)
{
    return (struct sockaddr *) &rqst->rq_daddr;
}

/*
 * Check buffer bounds after decoding arguments
 */
static inline int
xdr_argsize_check(struct svc_rqst *rqstp, __be32 *p)
{
    char *cp = (char *)p;
    struct kvec *vec = &rqstp->rq_arg.head[0];
    return cp >= (char*)vec->iov_base
        && cp <= (char*)vec->iov_base + vec->iov_len;
}

static inline int
xdr_ressize_check(struct svc_rqst *rqstp, __be32 *p)
{
    struct kvec *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 void svc_free_res_pages(struct svc_rqst *rqstp)
{
    while (rqstp->rq_resused) {
        struct page **pp = (rqstp->rq_respages +
                    --rqstp->rq_resused);
        if (*pp) {
            put_page(*pp);
            *pp = NULL;
        }
    }
}

struct svc_deferred_req {
    u32         prot;   /* protocol (UDP or TCP) */
    struct svc_xprt     *xprt;
    struct sockaddr_storage addr;   /* where reply must go */
    size_t          addrlen;
    struct sockaddr_storage daddr;  /* where reply must come from */
    size_t          daddrlen;
    struct cache_deferred_req handle;
    size_t          xprt_hlen;
    int         argslen;
    __be32          args[0];
};

/*
 * List of RPC programs on the same transport endpoint
 */
struct svc_program {
    struct svc_program *    pg_next;    /* other programs (same xprt) */
    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 */
    int         (*pg_authenticate)(struct svc_rqst *);
};

/*
 * 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 */

    unsigned int        vs_hidden : 1;  /* Don't register with portmapper.
                         * Only used for nfsacl so far. */

    /* 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 *, __be32 *);
};

/*
 * RPC procedure info
 */
typedef __be32  (*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 */
};

/*
 * Function prototypes.
 */
int svc_rpcb_setup(struct svc_serv *serv, struct net *net);
void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net);
int svc_bind(struct svc_serv *serv, struct net *net);
struct svc_serv *svc_create(struct svc_program *, unsigned int,
                void (*shutdown)(struct svc_serv *, struct net *net));
struct svc_rqst *svc_prepare_thread(struct svc_serv *serv,
                    struct svc_pool *pool, int node);
void           svc_exit_thread(struct svc_rqst *);
struct svc_serv *  svc_create_pooled(struct svc_program *, unsigned int,
            void (*shutdown)(struct svc_serv *, struct net *net),
            svc_thread_fn, struct module *);
int        svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
int        svc_pool_stats_open(struct svc_serv *serv, struct file *file);
void           svc_destroy(struct svc_serv *);
void           svc_shutdown_net(struct svc_serv *, struct net *);
int        svc_process(struct svc_rqst *);
int        bc_svc_process(struct svc_serv *, struct rpc_rqst *,
            struct svc_rqst *);
int        svc_register(const struct svc_serv *, struct net *, const int,
                const unsigned short, const unsigned short);

void           svc_wake_up(struct svc_serv *);
void           svc_reserve(struct svc_rqst *rqstp, int space);
struct svc_pool *  svc_pool_for_cpu(struct svc_serv *serv, int cpu);
char *         svc_print_addr(struct svc_rqst *, char *, size_t);

#define RPC_MAX_ADDRBUFLEN  (63U)

/*
 * When we want to reduce the size of the reserved space in the response
 * buffer, we need to take into account the size of any checksum data that
 * may be at the end of the packet. This is difficult to determine exactly
 * for all cases without actually generating the checksum, so we just use a
 * static value.
 */
static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space)
{
    int added_space = 0;

    if (rqstp->rq_authop->flavour)
        added_space = RPC_MAX_AUTH_SIZE;
    svc_reserve(rqstp, space + added_space);
}

#endif /* SUNRPC_SVC_H */