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