include/linux/sunrpc/svc.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * linux/include/linux/sunrpc/svc.h
   4  *
   5  * RPC server declarations.
   6  *
   7  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   8  */
   9
  10
  11 #ifndef SUNRPC_SVC_H
  12 #define SUNRPC_SVC_H
  13
  14 #include <linux/in.h>
  15 #include <linux/in6.h>
  16 #include <linux/sunrpc/types.h>
  17 #include <linux/sunrpc/xdr.h>
  18 #include <linux/sunrpc/auth.h>
  19 #include <linux/sunrpc/svcauth.h>
  20 #include <linux/wait.h>
  21 #include <linux/mm.h>
  22
  23 /* statistics for svc_pool structures */
  24 struct svc_pool_stats {
  25         atomic_long_t   packets;
  26         unsigned long   sockets_queued;
  27         atomic_long_t   threads_woken;
  28         atomic_long_t   threads_timedout;
  29 };
  30
  31 /*
  32  *
  33  * RPC service thread pool.
  34  *
  35  * Pool of threads and temporary sockets.  Generally there is only
  36  * a single one of these per RPC service, but on NUMA machines those
  37  * services that can benefit from it (i.e. nfs but not lockd) will
  38  * have one pool per NUMA node.  This optimisation reduces cross-
  39  * node traffic on multi-node NUMA NFS servers.
  40  */
  41 struct svc_pool {
  42         unsigned int            sp_id;          /* pool id; also node id on NUMA */
  43         spinlock_t              sp_lock;        /* protects all fields */
  44         struct list_head        sp_sockets;     /* pending sockets */
  45         unsigned int            sp_nrthreads;   /* # of threads in pool */
  46         struct list_head        sp_all_threads; /* all server threads */
  47         struct svc_pool_stats   sp_stats;       /* statistics on pool operation */
  48 #define SP_TASK_PENDING         (0)             /* still work to do even if no
  49                                                  * xprt is queued. */
  50 #define SP_CONGESTED            (1)
  51         unsigned long           sp_flags;
  52 } ____cacheline_aligned_in_smp;
  53
  54 struct svc_serv;
  55
  56 struct svc_serv_ops {
  57         /* Callback to use when last thread exits. */
  58         void            (*svo_shutdown)(struct svc_serv *, struct net *);
  59
  60         /* function for service threads to run */
  61         int             (*svo_function)(void *);
  62
  63         /* queue up a transport for servicing */
  64         void            (*svo_enqueue_xprt)(struct svc_xprt *);
  65
  66         /* set up thread (or whatever) execution context */
  67         int             (*svo_setup)(struct svc_serv *, struct svc_pool *, int);
  68
  69         /* optional module to count when adding threads (pooled svcs only) */
  70         struct module   *svo_module;
  71 };
  72
  73 /*
  74  * RPC service.
  75  *
  76  * An RPC service is a ``daemon,'' possibly multithreaded, which
  77  * receives and processes incoming RPC messages.
  78  * It has one or more transport sockets associated with it, and maintains
  79  * a list of idle threads waiting for input.
  80  *
  81  * We currently do not support more than one RPC program per daemon.
  82  */
  83 struct svc_serv {
  84         struct svc_program *    sv_program;     /* RPC program */
  85         struct svc_stat *       sv_stats;       /* RPC statistics */
  86         spinlock_t              sv_lock;
  87         unsigned int            sv_nrthreads;   /* # of server threads */
  88         unsigned int            sv_maxconn;     /* max connections allowed or
  89                                                  * '0' causing max to be based
  90                                                  * on number of threads. */
  91
  92         unsigned int            sv_max_payload; /* datagram payload size */
  93         unsigned int            sv_max_mesg;    /* max_payload + 1 page for overheads */
  94         unsigned int            sv_xdrsize;     /* XDR buffer size */
  95         struct list_head        sv_permsocks;   /* all permanent sockets */
  96         struct list_head        sv_tempsocks;   /* all temporary sockets */
  97         int                     sv_tmpcnt;      /* count of temporary sockets */
  98         struct timer_list       sv_temptimer;   /* timer for aging temporary sockets */
  99
 100         char *                  sv_name;        /* service name */
 101
 102         unsigned int            sv_nrpools;     /* number of thread pools */
 103         struct svc_pool *       sv_pools;       /* array of thread pools */
 104         const struct svc_serv_ops *sv_ops;      /* server operations */
 105 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 106         struct list_head        sv_cb_list;     /* queue for callback requests
 107                                                  * that arrive over the same
 108                                                  * connection */
 109         spinlock_t              sv_cb_lock;     /* protects the svc_cb_list */
 110         wait_queue_head_t       sv_cb_waitq;    /* sleep here if there are no
 111                                                  * entries in the svc_cb_list */
 112         struct svc_xprt         *sv_bc_xprt;    /* callback on fore channel */
 113 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 114 };
 115
 116 /*
 117  * We use sv_nrthreads as a reference count.  svc_destroy() drops
 118  * this refcount, so we need to bump it up around operations that
 119  * change the number of threads.  Horrible, but there it is.
 120  * Should be called with the "service mutex" held.
 121  */
 122 static inline void svc_get(struct svc_serv *serv)
 123 {
 124         serv->sv_nrthreads++;
 125 }
 126
 127 /*
 128  * Maximum payload size supported by a kernel RPC server.
 129  * This is use to determine the max number of pages nfsd is
 130  * willing to return in a single READ operation.
 131  *
 132  * These happen to all be powers of 2, which is not strictly
 133  * necessary but helps enforce the real limitation, which is
 134  * that they should be multiples of PAGE_SIZE.
 135  *
 136  * For UDP transports, a block plus NFS,RPC, and UDP headers
 137  * has to fit into the IP datagram limit of 64K.  The largest
 138  * feasible number for all known page sizes is probably 48K,
 139  * but we choose 32K here.  This is the same as the historical
 140  * Linux limit; someone who cares more about NFS/UDP performance
 141  * can test a larger number.
 142  *
 143  * For TCP transports we have more freedom.  A size of 1MB is
 144  * chosen to match the client limit.  Other OSes are known to
 145  * have larger limits, but those numbers are probably beyond
 146  * the point of diminishing returns.
 147  */
 148 #define RPCSVC_MAXPAYLOAD       (1*1024*1024u)
 149 #define RPCSVC_MAXPAYLOAD_TCP   RPCSVC_MAXPAYLOAD
 150 #define RPCSVC_MAXPAYLOAD_UDP   (32*1024u)
 151
 152 extern u32 svc_max_payload(const struct svc_rqst *rqstp);
 153
 154 /*
 155  * RPC Requsts and replies are stored in one or more pages.
 156  * We maintain an array of pages for each server thread.
 157  * Requests are copied into these pages as they arrive.  Remaining
 158  * pages are available to write the reply into.
 159  *
 160  * Pages are sent using ->sendpage so each server thread needs to
 161  * allocate more to replace those used in sending.  To help keep track
 162  * of these pages we have a receive list where all pages initialy live,
 163  * and a send list where pages are moved to when there are to be part
 164  * of a reply.
 165  *
 166  * We use xdr_buf for holding responses as it fits well with NFS
 167  * read responses (that have a header, and some data pages, and possibly
 168  * a tail) and means we can share some client side routines.
 169  *
 170  * The xdr_buf.head kvec always points to the first page in the rq_*pages
 171  * list.  The xdr_buf.pages pointer points to the second page on that
 172  * list.  xdr_buf.tail points to the end of the first page.
 173  * This assumes that the non-page part of an rpc reply will fit
 174  * in a page - NFSd ensures this.  lockd also has no trouble.
 175  *
 176  * Each request/reply pair can have at most one "payload", plus two pages,
 177  * one for the request, and one for the reply.
 178  * We using ->sendfile to return read data, we might need one extra page
 179  * if the request is not page-aligned.  So add another '1'.
 180  */
 181 #define RPCSVC_MAXPAGES         ((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE \
 182                                 + 2 + 1)
 183
 184 static inline u32 svc_getnl(struct kvec *iov)
 185 {
 186         __be32 val, *vp;
 187         vp = iov->iov_base;
 188         val = *vp++;
 189         iov->iov_base = (void*)vp;
 190         iov->iov_len -= sizeof(__be32);
 191         return ntohl(val);
 192 }
 193
 194 static inline void svc_putnl(struct kvec *iov, u32 val)
 195 {
 196         __be32 *vp = iov->iov_base + iov->iov_len;
 197         *vp = htonl(val);
 198         iov->iov_len += sizeof(__be32);
 199 }
 200
 201 static inline __be32 svc_getu32(struct kvec *iov)
 202 {
 203         __be32 val, *vp;
 204         vp = iov->iov_base;
 205         val = *vp++;
 206         iov->iov_base = (void*)vp;
 207         iov->iov_len -= sizeof(__be32);
 208         return val;
 209 }
 210
 211 static inline void svc_ungetu32(struct kvec *iov)
 212 {
 213         __be32 *vp = (__be32 *)iov->iov_base;
 214         iov->iov_base = (void *)(vp - 1);
 215         iov->iov_len += sizeof(*vp);
 216 }
 217
 218 static inline void svc_putu32(struct kvec *iov, __be32 val)
 219 {
 220         __be32 *vp = iov->iov_base + iov->iov_len;
 221         *vp = val;
 222         iov->iov_len += sizeof(__be32);
 223 }
 224
 225 /*
 226  * The context of a single thread, including the request currently being
 227  * processed.
 228  */
 229 struct svc_rqst {
 230         struct list_head        rq_all;         /* all threads list */
 231         struct rcu_head         rq_rcu_head;    /* for RCU deferred kfree */
 232         struct svc_xprt *       rq_xprt;        /* transport ptr */
 233
 234         struct sockaddr_storage rq_addr;        /* peer address */
 235         size_t                  rq_addrlen;
 236         struct sockaddr_storage rq_daddr;       /* dest addr of request
 237                                                  *  - reply from here */
 238         size_t                  rq_daddrlen;
 239
 240         struct svc_serv *       rq_server;      /* RPC service definition */
 241         struct svc_pool *       rq_pool;        /* thread pool */
 242         const struct svc_procedure *rq_procinfo;/* procedure info */
 243         struct auth_ops *       rq_authop;      /* authentication flavour */
 244         struct svc_cred         rq_cred;        /* auth info */
 245         void *                  rq_xprt_ctxt;   /* transport specific context ptr */
 246         struct svc_deferred_req*rq_deferred;    /* deferred request we are replaying */
 247
 248         size_t                  rq_xprt_hlen;   /* xprt header len */
 249         struct xdr_buf          rq_arg;
 250         struct xdr_buf          rq_res;
 251         struct page             *rq_pages[RPCSVC_MAXPAGES + 1];
 252         struct page *           *rq_respages;   /* points into rq_pages */
 253         struct page *           *rq_next_page; /* next reply page to use */
 254         struct page *           *rq_page_end;  /* one past the last page */
 255
 256         struct kvec             rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */
 257
 258         __be32                  rq_xid;         /* transmission id */
 259         u32                     rq_prog;        /* program number */
 260         u32                     rq_vers;        /* program version */
 261         u32                     rq_proc;        /* procedure number */
 262         u32                     rq_prot;        /* IP protocol */
 263         int                     rq_cachetype;   /* catering to nfsd */
 264 #define RQ_SECURE       (0)                     /* secure port */
 265 #define RQ_LOCAL        (1)                     /* local request */
 266 #define RQ_USEDEFERRAL  (2)                     /* use deferral */
 267 #define RQ_DROPME       (3)                     /* drop current reply */
 268 #define RQ_SPLICE_OK    (4)                     /* turned off in gss privacy
 269                                                  * to prevent encrypting page
 270                                                  * cache pages */
 271 #define RQ_VICTIM       (5)                     /* about to be shut down */
 272 #define RQ_BUSY         (6)                     /* request is busy */
 273 #define RQ_DATA         (7)                     /* request has data */
 274         unsigned long           rq_flags;       /* flags field */
 275
 276         void *                  rq_argp;        /* decoded arguments */
 277         void *                  rq_resp;        /* xdr'd results */
 278         void *                  rq_auth_data;   /* flavor-specific data */
 279         int                     rq_auth_slack;  /* extra space xdr code
 280                                                  * should leave in head
 281                                                  * for krb5i, krb5p.
 282                                                  */
 283         int                     rq_reserved;    /* space on socket outq
 284                                                  * reserved for this request
 285                                                  */
 286
 287         struct cache_req        rq_chandle;     /* handle passed to caches for
 288                                                  * request delaying
 289                                                  */
 290         /* Catering to nfsd */
 291         struct auth_domain *    rq_client;      /* RPC peer info */
 292         struct auth_domain *    rq_gssclient;   /* "gss/"-style peer info */
 293         struct svc_cacherep *   rq_cacherep;    /* cache info */
 294         struct task_struct      *rq_task;       /* service thread */
 295         spinlock_t              rq_lock;        /* per-request lock */
 296         struct net              *rq_bc_net;     /* pointer to backchannel's
 297                                                  * net namespace
 298                                                  */
 299 };
 300
 301 #define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net)
 302
 303 /*
 304  * Rigorous type checking on sockaddr type conversions
 305  */
 306 static inline struct sockaddr_in *svc_addr_in(const struct svc_rqst *rqst)
 307 {
 308         return (struct sockaddr_in *) &rqst->rq_addr;
 309 }
 310
 311 static inline struct sockaddr_in6 *svc_addr_in6(const struct svc_rqst *rqst)
 312 {
 313         return (struct sockaddr_in6 *) &rqst->rq_addr;
 314 }
 315
 316 static inline struct sockaddr *svc_addr(const struct svc_rqst *rqst)
 317 {
 318         return (struct sockaddr *) &rqst->rq_addr;
 319 }
 320
 321 static inline struct sockaddr_in *svc_daddr_in(const struct svc_rqst *rqst)
 322 {
 323         return (struct sockaddr_in *) &rqst->rq_daddr;
 324 }
 325
 326 static inline struct sockaddr_in6 *svc_daddr_in6(const struct svc_rqst *rqst)
 327 {
 328         return (struct sockaddr_in6 *) &rqst->rq_daddr;
 329 }
 330
 331 static inline struct sockaddr *svc_daddr(const struct svc_rqst *rqst)
 332 {
 333         return (struct sockaddr *) &rqst->rq_daddr;
 334 }
 335
 336 /*
 337  * Check buffer bounds after decoding arguments
 338  */
 339 static inline int
 340 xdr_argsize_check(struct svc_rqst *rqstp, __be32 *p)
 341 {
 342         char *cp = (char *)p;
 343         struct kvec *vec = &rqstp->rq_arg.head[0];
 344         return cp >= (char*)vec->iov_base
 345                 && cp <= (char*)vec->iov_base + vec->iov_len;
 346 }
 347
 348 static inline int
 349 xdr_ressize_check(struct svc_rqst *rqstp, __be32 *p)
 350 {
 351         struct kvec *vec = &rqstp->rq_res.head[0];
 352         char *cp = (char*)p;
 353
 354         vec->iov_len = cp - (char*)vec->iov_base;
 355
 356         return vec->iov_len <= PAGE_SIZE;
 357 }
 358
 359 static inline void svc_free_res_pages(struct svc_rqst *rqstp)
 360 {
 361         while (rqstp->rq_next_page != rqstp->rq_respages) {
 362                 struct page **pp = --rqstp->rq_next_page;
 363                 if (*pp) {
 364                         put_page(*pp);
 365                         *pp = NULL;
 366                 }
 367         }
 368 }
 369
 370 struct svc_deferred_req {
 371         u32                     prot;   /* protocol (UDP or TCP) */
 372         struct svc_xprt         *xprt;
 373         struct sockaddr_storage addr;   /* where reply must go */
 374         size_t                  addrlen;
 375         struct sockaddr_storage daddr;  /* where reply must come from */
 376         size_t                  daddrlen;
 377         struct cache_deferred_req handle;
 378         size_t                  xprt_hlen;
 379         int                     argslen;
 380         __be32                  args[0];
 381 };
 382
 383 /*
 384  * List of RPC programs on the same transport endpoint
 385  */
 386 struct svc_program {
 387         struct svc_program *    pg_next;        /* other programs (same xprt) */
 388         u32                     pg_prog;        /* program number */
 389         unsigned int            pg_lovers;      /* lowest version */
 390         unsigned int            pg_hivers;      /* highest version */
 391         unsigned int            pg_nvers;       /* number of versions */
 392         const struct svc_version **pg_vers;     /* version array */
 393         char *                  pg_name;        /* service name */
 394         char *                  pg_class;       /* class name: services sharing authentication */
 395         struct svc_stat *       pg_stats;       /* rpc statistics */
 396         int                     (*pg_authenticate)(struct svc_rqst *);
 397 };
 398
 399 /*
 400  * RPC program version
 401  */
 402 struct svc_version {
 403         u32                     vs_vers;        /* version number */
 404         u32                     vs_nproc;       /* number of procedures */
 405         const struct svc_procedure *vs_proc;    /* per-procedure info */
 406         unsigned int            *vs_count;      /* call counts */
 407         u32                     vs_xdrsize;     /* xdrsize needed for this version */
 408
 409         /* Don't register with rpcbind */
 410         bool                    vs_hidden;
 411
 412         /* Don't care if the rpcbind registration fails */
 413         bool                    vs_rpcb_optnl;
 414
 415         /* Need xprt with congestion control */
 416         bool                    vs_need_cong_ctrl;
 417
 418         /* Override dispatch function (e.g. when caching replies).
 419          * A return value of 0 means drop the request.
 420          * vs_dispatch == NULL means use default dispatcher.
 421          */
 422         int                     (*vs_dispatch)(struct svc_rqst *, __be32 *);
 423 };
 424
 425 /*
 426  * RPC procedure info
 427  */
 428 struct svc_procedure {
 429         /* process the request: */
 430         __be32                  (*pc_func)(struct svc_rqst *);
 431         /* XDR decode args: */
 432         int                     (*pc_decode)(struct svc_rqst *, __be32 *data);
 433         /* XDR encode result: */
 434         int                     (*pc_encode)(struct svc_rqst *, __be32 *data);
 435         /* XDR free result: */
 436         void                    (*pc_release)(struct svc_rqst *);
 437         unsigned int            pc_argsize;     /* argument struct size */
 438         unsigned int            pc_ressize;     /* result struct size */
 439         unsigned int            pc_cachetype;   /* cache info (NFS) */
 440         unsigned int            pc_xdrressize;  /* maximum size of XDR reply */
 441 };
 442
 443 /*
 444  * Mode for mapping cpus to pools.
 445  */
 446 enum {
 447         SVC_POOL_AUTO = -1,     /* choose one of the others */
 448         SVC_POOL_GLOBAL,        /* no mapping, just a single global pool
 449                                  * (legacy & UP mode) */
 450         SVC_POOL_PERCPU,        /* one pool per cpu */
 451         SVC_POOL_PERNODE        /* one pool per numa node */
 452 };
 453
 454 struct svc_pool_map {
 455         int count;                      /* How many svc_servs use us */
 456         int mode;                       /* Note: int not enum to avoid
 457                                          * warnings about "enumeration value
 458                                          * not handled in switch" */
 459         unsigned int npools;
 460         unsigned int *pool_to;          /* maps pool id to cpu or node */
 461         unsigned int *to_pool;          /* maps cpu or node to pool id */
 462 };
 463
 464 extern struct svc_pool_map svc_pool_map;
 465
 466 /*
 467  * Function prototypes.
 468  */
 469 int svc_rpcb_setup(struct svc_serv *serv, struct net *net);
 470 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net);
 471 int svc_bind(struct svc_serv *serv, struct net *net);
 472 struct svc_serv *svc_create(struct svc_program *, unsigned int,
 473                             const struct svc_serv_ops *);
 474 struct svc_rqst *svc_rqst_alloc(struct svc_serv *serv,
 475                                         struct svc_pool *pool, int node);
 476 struct svc_rqst *svc_prepare_thread(struct svc_serv *serv,
 477                                         struct svc_pool *pool, int node);
 478 void               svc_rqst_free(struct svc_rqst *);
 479 void               svc_exit_thread(struct svc_rqst *);
 480 unsigned int       svc_pool_map_get(void);
 481 void               svc_pool_map_put(void);
 482 struct svc_serv *  svc_create_pooled(struct svc_program *, unsigned int,
 483                         const struct svc_serv_ops *);
 484 int                svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
 485 int                svc_set_num_threads_sync(struct svc_serv *, struct svc_pool *, int);
 486 int                svc_pool_stats_open(struct svc_serv *serv, struct file *file);
 487 void               svc_destroy(struct svc_serv *);
 488 void               svc_shutdown_net(struct svc_serv *, struct net *);
 489 int                svc_process(struct svc_rqst *);
 490 int                bc_svc_process(struct svc_serv *, struct rpc_rqst *,
 491                         struct svc_rqst *);
 492 int                svc_register(const struct svc_serv *, struct net *, const int,
 493                                 const unsigned short, const unsigned short);
 494
 495 void               svc_wake_up(struct svc_serv *);
 496 void               svc_reserve(struct svc_rqst *rqstp, int space);
 497 struct svc_pool *  svc_pool_for_cpu(struct svc_serv *serv, int cpu);
 498 char *             svc_print_addr(struct svc_rqst *, char *, size_t);
 499
 500 #define RPC_MAX_ADDRBUFLEN      (63U)
 501
 502 /*
 503  * When we want to reduce the size of the reserved space in the response
 504  * buffer, we need to take into account the size of any checksum data that
 505  * may be at the end of the packet. This is difficult to determine exactly
 506  * for all cases without actually generating the checksum, so we just use a
 507  * static value.
 508  */
 509 static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space)
 510 {
 511         svc_reserve(rqstp, space + rqstp->rq_auth_slack);
 512 }
 513
 514 #endif /* SUNRPC_SVC_H */