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