include/linux/sunrpc/svc.h

   1 /*
   2  * linux/include/linux/sunrpc/svc.h
   3  *
   4  * RPC server declarations.
   5  *
   6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9
  10 #ifndef SUNRPC_SVC_H
  11 #define SUNRPC_SVC_H
  12
  13 #include <linux/in.h>
  14 #include <linux/in6.h>
  15 #include <linux/sunrpc/types.h>
  16 #include <linux/sunrpc/xdr.h>
  17 #include <linux/sunrpc/auth.h>
  18 #include <linux/sunrpc/svcauth.h>
  19 #include <linux/wait.h>
  20 #include <linux/mm.h>
  21
  22 /*
  23  * This is the RPC server thread function prototype
  24  */
  25 typedef int             (*svc_thread_fn)(void *);
  26
  27 /* statistics for svc_pool structures */
  28 struct svc_pool_stats {
  29         unsigned long   packets;
  30         unsigned long   sockets_queued;
  31         unsigned long   threads_woken;
  32         unsigned long   overloads_avoided;
  33         unsigned long   threads_timedout;
  34 };
  35
  36 /*
  37  *
  38  * RPC service thread pool.
  39  *
  40  * Pool of threads and temporary sockets.  Generally there is only
  41  * a single one of these per RPC service, but on NUMA machines those
  42  * services that can benefit from it (i.e. nfs but not lockd) will
  43  * have one pool per NUMA node.  This optimisation reduces cross-
  44  * node traffic on multi-node NUMA NFS servers.
  45  */
  46 struct svc_pool {
  47         unsigned int            sp_id;          /* pool id; also node id on NUMA */
  48         spinlock_t              sp_lock;        /* protects all fields */
  49         struct list_head        sp_threads;     /* idle server threads */
  50         struct list_head        sp_sockets;     /* pending sockets */
  51         unsigned int            sp_nrthreads;   /* # of threads in pool */
  52         struct list_head        sp_all_threads; /* all server threads */
  53         int                     sp_nwaking;     /* number of threads woken but not yet active */
  54         struct svc_pool_stats   sp_stats;       /* statistics on pool operation */
  55 } ____cacheline_aligned_in_smp;
  56
  57 /*
  58  * RPC service.
  59  *
  60  * An RPC service is a ``daemon,'' possibly multithreaded, which
  61  * receives and processes incoming RPC messages.
  62  * It has one or more transport sockets associated with it, and maintains
  63  * a list of idle threads waiting for input.
  64  *
  65  * We currently do not support more than one RPC program per daemon.
  66  */
  67 struct svc_serv {
  68         struct svc_program *    sv_program;     /* RPC program */
  69         struct svc_stat *       sv_stats;       /* RPC statistics */
  70         spinlock_t              sv_lock;
  71         unsigned int            sv_nrthreads;   /* # of server threads */
  72         unsigned int            sv_maxconn;     /* max connections allowed or
  73                                                  * '0' causing max to be based
  74                                                  * on number of threads. */
  75
  76         unsigned int            sv_max_payload; /* datagram payload size */
  77         unsigned int            sv_max_mesg;    /* max_payload + 1 page for overheads */
  78         unsigned int            sv_xdrsize;     /* XDR buffer size */
  79         struct list_head        sv_permsocks;   /* all permanent sockets */
  80         struct list_head        sv_tempsocks;   /* all temporary sockets */
  81         int                     sv_tmpcnt;      /* count of temporary sockets */
  82         struct timer_list       sv_temptimer;   /* timer for aging temporary sockets */
  83
  84         char *                  sv_name;        /* service name */
  85
  86         unsigned int            sv_nrpools;     /* number of thread pools */
  87         struct svc_pool *       sv_pools;       /* array of thread pools */
  88
  89         void                    (*sv_shutdown)(struct svc_serv *serv);
  90                                                 /* Callback to use when last thread
  91                                                  * exits.
  92                                                  */
  93
  94         struct module *         sv_module;      /* optional module to count when
  95                                                  * adding threads */
  96         svc_thread_fn           sv_function;    /* main function for threads */
  97 #if defined(CONFIG_NFS_V4_1)
  98         struct list_head        sv_cb_list;     /* queue for callback requests
  99                                                  * that arrive over the same
 100                                                  * connection */
 101         spinlock_t              sv_cb_lock;     /* protects the svc_cb_list */
 102         wait_queue_head_t       sv_cb_waitq;    /* sleep here if there are no
 103                                                  * entries in the svc_cb_list */
 104         struct svc_xprt         *bc_xprt;
 105 #endif /* CONFIG_NFS_V4_1 */
 106 };
 107
 108 /*
 109  * We use sv_nrthreads as a reference count.  svc_destroy() drops
 110  * this refcount, so we need to bump it up around operations that
 111  * change the number of threads.  Horrible, but there it is.
 112  * Should be called with the BKL held.
 113  */
 114 static inline void svc_get(struct svc_serv *serv)
 115 {
 116         serv->sv_nrthreads++;
 117 }
 118
 119 /*
 120  * Maximum payload size supported by a kernel RPC server.
 121  * This is use to determine the max number of pages nfsd is
 122  * willing to return in a single READ operation.
 123  *
 124  * These happen to all be powers of 2, which is not strictly
 125  * necessary but helps enforce the real limitation, which is
 126  * that they should be multiples of PAGE_CACHE_SIZE.
 127  *
 128  * For UDP transports, a block plus NFS,RPC, and UDP headers
 129  * has to fit into the IP datagram limit of 64K.  The largest
 130  * feasible number for all known page sizes is probably 48K,
 131  * but we choose 32K here.  This is the same as the historical
 132  * Linux limit; someone who cares more about NFS/UDP performance
 133  * can test a larger number.
 134  *
 135  * For TCP transports we have more freedom.  A size of 1MB is
 136  * chosen to match the client limit.  Other OSes are known to
 137  * have larger limits, but those numbers are probably beyond
 138  * the point of diminishing returns.
 139  */
 140 #define RPCSVC_MAXPAYLOAD       (1*1024*1024u)
 141 #define RPCSVC_MAXPAYLOAD_TCP   RPCSVC_MAXPAYLOAD
 142 #define RPCSVC_MAXPAYLOAD_UDP   (32*1024u)
 143
 144 extern u32 svc_max_payload(const struct svc_rqst *rqstp);
 145
 146 /*
 147  * RPC Requsts and replies are stored in one or more pages.
 148  * We maintain an array of pages for each server thread.
 149  * Requests are copied into these pages as they arrive.  Remaining
 150  * pages are available to write the reply into.
 151  *
 152  * Pages are sent using ->sendpage so each server thread needs to
 153  * allocate more to replace those used in sending.  To help keep track
 154  * of these pages we have a receive list where all pages initialy live,
 155  * and a send list where pages are moved to when there are to be part
 156  * of a reply.
 157  *
 158  * We use xdr_buf for holding responses as it fits well with NFS
 159  * read responses (that have a header, and some data pages, and possibly
 160  * a tail) and means we can share some client side routines.
 161  *
 162  * The xdr_buf.head kvec always points to the first page in the rq_*pages
 163  * list.  The xdr_buf.pages pointer points to the second page on that
 164  * list.  xdr_buf.tail points to the end of the first page.
 165  * This assumes that the non-page part of an rpc reply will fit
 166  * in a page - NFSd ensures this.  lockd also has no trouble.
 167  *
 168  * Each request/reply pair can have at most one "payload", plus two pages,
 169  * one for the request, and one for the reply.
 170  * We using ->sendfile to return read data, we might need one extra page
 171  * if the request is not page-aligned.  So add another '1'.
 172  */
 173 #define RPCSVC_MAXPAGES         ((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE \
 174                                 + 2 + 1)
 175
 176 static inline u32 svc_getnl(struct kvec *iov)
 177 {
 178         __be32 val, *vp;
 179         vp = iov->iov_base;
 180         val = *vp++;
 181         iov->iov_base = (void*)vp;
 182         iov->iov_len -= sizeof(__be32);
 183         return ntohl(val);
 184 }
 185
 186 static inline void svc_putnl(struct kvec *iov, u32 val)
 187 {
 188         __be32 *vp = iov->iov_base + iov->iov_len;
 189         *vp = htonl(val);
 190         iov->iov_len += sizeof(__be32);
 191 }
 192
 193 static inline __be32 svc_getu32(struct kvec *iov)
 194 {
 195         __be32 val, *vp;
 196         vp = iov->iov_base;
 197         val = *vp++;
 198         iov->iov_base = (void*)vp;
 199         iov->iov_len -= sizeof(__be32);
 200         return val;
 201 }
 202
 203 static inline void svc_ungetu32(struct kvec *iov)
 204 {
 205         __be32 *vp = (__be32 *)iov->iov_base;
 206         iov->iov_base = (void *)(vp - 1);
 207         iov->iov_len += sizeof(*vp);
 208 }
 209
 210 static inline void svc_putu32(struct kvec *iov, __be32 val)
 211 {
 212         __be32 *vp = iov->iov_base + iov->iov_len;
 213         *vp = val;
 214         iov->iov_len += sizeof(__be32);
 215 }
 216
 217 union svc_addr_u {
 218     struct in_addr      addr;
 219     struct in6_addr     addr6;
 220 };
 221
 222 /*
 223  * The context of a single thread, including the request currently being
 224  * processed.
 225  */
 226 struct svc_rqst {
 227         struct list_head        rq_list;        /* idle list */
 228         struct list_head        rq_all;         /* all threads list */
 229         struct svc_xprt *       rq_xprt;        /* transport ptr */
 230         struct sockaddr_storage rq_addr;        /* peer address */
 231         size_t                  rq_addrlen;
 232
 233         struct svc_serv *       rq_server;      /* RPC service definition */
 234         struct svc_pool *       rq_pool;        /* thread pool */
 235         struct svc_procedure *  rq_procinfo;    /* procedure info */
 236         struct auth_ops *       rq_authop;      /* authentication flavour */
 237         u32                     rq_flavor;      /* pseudoflavor */
 238         struct svc_cred         rq_cred;        /* auth info */
 239         void *                  rq_xprt_ctxt;   /* transport specific context ptr */
 240         struct svc_deferred_req*rq_deferred;    /* deferred request we are replaying */
 241         int                     rq_usedeferral; /* use deferral */
 242
 243         size_t                  rq_xprt_hlen;   /* xprt header len */
 244         struct xdr_buf          rq_arg;
 245         struct xdr_buf          rq_res;
 246         struct page *           rq_pages[RPCSVC_MAXPAGES];
 247         struct page *           *rq_respages;   /* points into rq_pages */
 248         int                     rq_resused;     /* number of pages used for result */
 249
 250         struct kvec             rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */
 251
 252         __be32                  rq_xid;         /* transmission id */
 253         u32                     rq_prog;        /* program number */
 254         u32                     rq_vers;        /* program version */
 255         u32                     rq_proc;        /* procedure number */
 256         u32                     rq_prot;        /* IP protocol */
 257         unsigned short
 258                                 rq_secure  : 1; /* secure port */
 259
 260         union svc_addr_u        rq_daddr;       /* dest addr of request
 261                                                  *  - reply from here */
 262
 263         void *                  rq_argp;        /* decoded arguments */
 264         void *                  rq_resp;        /* xdr'd results */
 265         void *                  rq_auth_data;   /* flavor-specific data */
 266
 267         int                     rq_reserved;    /* space on socket outq
 268                                                  * reserved for this request
 269                                                  */
 270
 271         struct cache_req        rq_chandle;     /* handle passed to caches for
 272                                                  * request delaying
 273                                                  */
 274         /* Catering to nfsd */
 275         struct auth_domain *    rq_client;      /* RPC peer info */
 276         struct auth_domain *    rq_gssclient;   /* "gss/"-style peer info */
 277         struct svc_cacherep *   rq_cacherep;    /* cache info */
 278         struct knfsd_fh *       rq_reffh;       /* Referrence filehandle, used to
 279                                                  * determine what device number
 280                                                  * to report (real or virtual)
 281                                                  */
 282         int                     rq_splice_ok;   /* turned off in gss privacy
 283                                                  * to prevent encrypting page
 284                                                  * cache pages */
 285         wait_queue_head_t       rq_wait;        /* synchronization */
 286         struct task_struct      *rq_task;       /* service thread */
 287         int                     rq_waking;      /* 1 if thread is being woken */
 288 };
 289
 290 /*
 291  * Rigorous type checking on sockaddr type conversions
 292  */
 293 static inline struct sockaddr_in *svc_addr_in(const struct svc_rqst *rqst)
 294 {
 295         return (struct sockaddr_in *) &rqst->rq_addr;
 296 }
 297
 298 static inline struct sockaddr_in6 *svc_addr_in6(const struct svc_rqst *rqst)
 299 {
 300         return (struct sockaddr_in6 *) &rqst->rq_addr;
 301 }
 302
 303 static inline struct sockaddr *svc_addr(const struct svc_rqst *rqst)
 304 {
 305         return (struct sockaddr *) &rqst->rq_addr;
 306 }
 307
 308 /*
 309  * Check buffer bounds after decoding arguments
 310  */
 311 static inline int
 312 xdr_argsize_check(struct svc_rqst *rqstp, __be32 *p)
 313 {
 314         char *cp = (char *)p;
 315         struct kvec *vec = &rqstp->rq_arg.head[0];
 316         return cp >= (char*)vec->iov_base
 317                 && cp <= (char*)vec->iov_base + vec->iov_len;
 318 }
 319
 320 static inline int
 321 xdr_ressize_check(struct svc_rqst *rqstp, __be32 *p)
 322 {
 323         struct kvec *vec = &rqstp->rq_res.head[0];
 324         char *cp = (char*)p;
 325
 326         vec->iov_len = cp - (char*)vec->iov_base;
 327
 328         return vec->iov_len <= PAGE_SIZE;
 329 }
 330
 331 static inline void svc_free_res_pages(struct svc_rqst *rqstp)
 332 {
 333         while (rqstp->rq_resused) {
 334                 struct page **pp = (rqstp->rq_respages +
 335                                     --rqstp->rq_resused);
 336                 if (*pp) {
 337                         put_page(*pp);
 338                         *pp = NULL;
 339                 }
 340         }
 341 }
 342
 343 struct svc_deferred_req {
 344         u32                     prot;   /* protocol (UDP or TCP) */
 345         struct svc_xprt         *xprt;
 346         struct sockaddr_storage addr;   /* where reply must go */
 347         size_t                  addrlen;
 348         union svc_addr_u        daddr;  /* where reply must come from */
 349         struct cache_deferred_req handle;
 350         size_t                  xprt_hlen;
 351         int                     argslen;
 352         __be32                  args[0];
 353 };
 354
 355 /*
 356  * List of RPC programs on the same transport endpoint
 357  */
 358 struct svc_program {
 359         struct svc_program *    pg_next;        /* other programs (same xprt) */
 360         u32                     pg_prog;        /* program number */
 361         unsigned int            pg_lovers;      /* lowest version */
 362         unsigned int            pg_hivers;      /* lowest version */
 363         unsigned int            pg_nvers;       /* number of versions */
 364         struct svc_version **   pg_vers;        /* version array */
 365         char *                  pg_name;        /* service name */
 366         char *                  pg_class;       /* class name: services sharing authentication */
 367         struct svc_stat *       pg_stats;       /* rpc statistics */
 368         int                     (*pg_authenticate)(struct svc_rqst *);
 369 };
 370
 371 /*
 372  * RPC program version
 373  */
 374 struct svc_version {
 375         u32                     vs_vers;        /* version number */
 376         u32                     vs_nproc;       /* number of procedures */
 377         struct svc_procedure *  vs_proc;        /* per-procedure info */
 378         u32                     vs_xdrsize;     /* xdrsize needed for this version */
 379
 380         unsigned int            vs_hidden : 1;  /* Don't register with portmapper.
 381                                                  * Only used for nfsacl so far. */
 382
 383         /* Override dispatch function (e.g. when caching replies).
 384          * A return value of 0 means drop the request.
 385          * vs_dispatch == NULL means use default dispatcher.
 386          */
 387         int                     (*vs_dispatch)(struct svc_rqst *, __be32 *);
 388 };
 389
 390 /*
 391  * RPC procedure info
 392  */
 393 typedef __be32  (*svc_procfunc)(struct svc_rqst *, void *argp, void *resp);
 394 struct svc_procedure {
 395         svc_procfunc            pc_func;        /* process the request */
 396         kxdrproc_t              pc_decode;      /* XDR decode args */
 397         kxdrproc_t              pc_encode;      /* XDR encode result */
 398         kxdrproc_t              pc_release;     /* XDR free result */
 399         unsigned int            pc_argsize;     /* argument struct size */
 400         unsigned int            pc_ressize;     /* result struct size */
 401         unsigned int            pc_count;       /* call count */
 402         unsigned int            pc_cachetype;   /* cache info (NFS) */
 403         unsigned int            pc_xdrressize;  /* maximum size of XDR reply */
 404 };
 405
 406 /*
 407  * Function prototypes.
 408  */
 409 struct svc_serv *svc_create(struct svc_program *, unsigned int,
 410                             void (*shutdown)(struct svc_serv *));
 411 struct svc_rqst *svc_prepare_thread(struct svc_serv *serv,
 412                                         struct svc_pool *pool);
 413 void               svc_exit_thread(struct svc_rqst *);
 414 struct svc_serv *  svc_create_pooled(struct svc_program *, unsigned int,
 415                         void (*shutdown)(struct svc_serv *),
 416                         svc_thread_fn, struct module *);
 417 int                svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
 418 int                svc_pool_stats_open(struct svc_serv *serv, struct file *file);
 419 void               svc_destroy(struct svc_serv *);
 420 int                svc_process(struct svc_rqst *);
 421 int                bc_svc_process(struct svc_serv *, struct rpc_rqst *,
 422                         struct svc_rqst *);
 423 int                svc_register(const struct svc_serv *, const int,
 424                                 const unsigned short, const unsigned short);
 425
 426 void               svc_wake_up(struct svc_serv *);
 427 void               svc_reserve(struct svc_rqst *rqstp, int space);
 428 struct svc_pool *  svc_pool_for_cpu(struct svc_serv *serv, int cpu);
 429 char *             svc_print_addr(struct svc_rqst *, char *, size_t);
 430
 431 #define RPC_MAX_ADDRBUFLEN      (63U)
 432
 433 /*
 434  * When we want to reduce the size of the reserved space in the response
 435  * buffer, we need to take into account the size of any checksum data that
 436  * may be at the end of the packet. This is difficult to determine exactly
 437  * for all cases without actually generating the checksum, so we just use a
 438  * static value.
 439  */
 440 static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space)
 441 {
 442         int added_space = 0;
 443
 444         if (rqstp->rq_authop->flavour)
 445                 added_space = RPC_MAX_AUTH_SIZE;
 446         svc_reserve(rqstp, space + added_space);
 447 }
 448
 449 #endif /* SUNRPC_SVC_H */