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 <[email protected]> 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/lwq.h> 21 #include <linux/wait.h> 22 #include <linux/mm.h> 23 #include <linux/pagevec.h> 24 25 /* 26 * 27 * RPC service thread pool. 28 * 29 * Pool of threads and temporary sockets. Generally there is only 30 * a single one of these per RPC service, but on NUMA machines those 31 * services that can benefit from it (i.e. nfs but not lockd) will 32 * have one pool per NUMA node. This optimisation reduces cross- 33 * node traffic on multi-node NUMA NFS servers. 34 */ 35 struct svc_pool { 36 unsigned int sp_id; /* pool id; also node id on NUMA */ 37 struct lwq sp_xprts; /* pending transports */ 38 atomic_t sp_nrthreads; /* # of threads in pool */ 39 struct list_head sp_all_threads; /* all server threads */ 40 struct llist_head sp_idle_threads; /* idle server threads */ 41 42 /* statistics on pool operation */ 43 struct percpu_counter sp_messages_arrived; 44 struct percpu_counter sp_sockets_queued; 45 struct percpu_counter sp_threads_woken; 46 47 unsigned long sp_flags; 48 } ____cacheline_aligned_in_smp; 49 50 /* bits for sp_flags */ 51 enum { 52 SP_TASK_PENDING, /* still work to do even if no xprt is queued */ 53 SP_NEED_VICTIM, /* One thread needs to agree to exit */ 54 SP_VICTIM_REMAINS, /* One thread needs to actually exit */ 55 }; 56 57 58 /* 59 * RPC service. 60 * 61 * An RPC service is a ``daemon,'' possibly multithreaded, which 62 * receives and processes incoming RPC messages. 63 * It has one or more transport sockets associated with it, and maintains 64 * a list of idle threads waiting for input. 65 * 66 * We currently do not support more than one RPC program per daemon. 67 */ 68 struct svc_serv { 69 struct svc_program * sv_program; /* RPC program */ 70 struct svc_stat * sv_stats; /* RPC statistics */ 71 spinlock_t sv_lock; 72 struct kref sv_refcnt; 73 unsigned int sv_nrthreads; /* # of server threads */ 74 unsigned int sv_maxconn; /* max connections allowed or 75 * '0' causing max to be based 76 * on number of threads. */ 77 78 unsigned int sv_max_payload; /* datagram payload size */ 79 unsigned int sv_max_mesg; /* max_payload + 1 page for overheads */ 80 unsigned int sv_xdrsize; /* XDR buffer size */ 81 struct list_head sv_permsocks; /* all permanent sockets */ 82 struct list_head sv_tempsocks; /* all temporary sockets */ 83 int sv_tmpcnt; /* count of temporary sockets */ 84 struct timer_list sv_temptimer; /* timer for aging temporary sockets */ 85 86 char * sv_name; /* service name */ 87 88 unsigned int sv_nrpools; /* number of thread pools */ 89 struct svc_pool * sv_pools; /* array of thread pools */ 90 int (*sv_threadfn)(void *data); 91 92 #if defined(CONFIG_SUNRPC_BACKCHANNEL) 93 struct lwq sv_cb_list; /* queue for callback requests 94 * that arrive over the same 95 * connection */ 96 bool sv_bc_enabled; /* service uses backchannel */ 97 #endif /* CONFIG_SUNRPC_BACKCHANNEL */ 98 }; 99 100 /** 101 * svc_get() - increment reference count on a SUNRPC serv 102 * @serv: the svc_serv to have count incremented 103 * 104 * Returns: the svc_serv that was passed in. 105 */ 106 static inline struct svc_serv *svc_get(struct svc_serv *serv) 107 { 108 kref_get(&serv->sv_refcnt); 109 return serv; 110 } 111 112 void svc_destroy(struct kref *); 113 114 /** 115 * svc_put - decrement reference count on a SUNRPC serv 116 * @serv: the svc_serv to have count decremented 117 * 118 * When the reference count reaches zero, svc_destroy() 119 * is called to clean up and free the serv. 120 */ 121 static inline void svc_put(struct svc_serv *serv) 122 { 123 kref_put(&serv->sv_refcnt, svc_destroy); 124 } 125 126 /* 127 * Maximum payload size supported by a kernel RPC server. 128 * This is use to determine the max number of pages nfsd is 129 * willing to return in a single READ operation. 130 * 131 * These happen to all be powers of 2, which is not strictly 132 * necessary but helps enforce the real limitation, which is 133 * that they should be multiples of PAGE_SIZE. 134 * 135 * For UDP transports, a block plus NFS,RPC, and UDP headers 136 * has to fit into the IP datagram limit of 64K. The largest 137 * feasible number for all known page sizes is probably 48K, 138 * but we choose 32K here. This is the same as the historical 139 * Linux limit; someone who cares more about NFS/UDP performance 140 * can test a larger number. 141 * 142 * For TCP transports we have more freedom. A size of 1MB is 143 * chosen to match the client limit. Other OSes are known to 144 * have larger limits, but those numbers are probably beyond 145 * the point of diminishing returns. 146 */ 147 #define RPCSVC_MAXPAYLOAD (1*1024*1024u) 148 #define RPCSVC_MAXPAYLOAD_TCP RPCSVC_MAXPAYLOAD 149 #define RPCSVC_MAXPAYLOAD_UDP (32*1024u) 150 151 extern u32 svc_max_payload(const struct svc_rqst *rqstp); 152 153 /* 154 * RPC Requests and replies are stored in one or more pages. 155 * We maintain an array of pages for each server thread. 156 * Requests are copied into these pages as they arrive. Remaining 157 * pages are available to write the reply into. 158 * 159 * Pages are sent using ->sendmsg with MSG_SPLICE_PAGES so each server thread 160 * needs to allocate more to replace those used in sending. To help keep track 161 * of these pages we have a receive list where all pages initialy live, and a 162 * send list where pages are moved to when there are to be part of a reply. 163 * 164 * We use xdr_buf for holding responses as it fits well with NFS 165 * read responses (that have a header, and some data pages, and possibly 166 * a tail) and means we can share some client side routines. 167 * 168 * The xdr_buf.head kvec always points to the first page in the rq_*pages 169 * list. The xdr_buf.pages pointer points to the second page on that 170 * list. xdr_buf.tail points to the end of the first page. 171 * This assumes that the non-page part of an rpc reply will fit 172 * in a page - NFSd ensures this. lockd also has no trouble. 173 * 174 * Each request/reply pair can have at most one "payload", plus two pages, 175 * one for the request, and one for the reply. 176 * We using ->sendfile to return read data, we might need one extra page 177 * if the request is not page-aligned. So add another '1'. 178 */ 179 #define RPCSVC_MAXPAGES ((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE \ 180 + 2 + 1) 181 182 /* 183 * The context of a single thread, including the request currently being 184 * processed. 185 */ 186 struct svc_rqst { 187 struct list_head rq_all; /* all threads list */ 188 struct llist_node rq_idle; /* On the idle list */ 189 struct rcu_head rq_rcu_head; /* for RCU deferred kfree */ 190 struct svc_xprt * rq_xprt; /* transport ptr */ 191 192 struct sockaddr_storage rq_addr; /* peer address */ 193 size_t rq_addrlen; 194 struct sockaddr_storage rq_daddr; /* dest addr of request 195 * - reply from here */ 196 size_t rq_daddrlen; 197 198 struct svc_serv * rq_server; /* RPC service definition */ 199 struct svc_pool * rq_pool; /* thread pool */ 200 const struct svc_procedure *rq_procinfo;/* procedure info */ 201 struct auth_ops * rq_authop; /* authentication flavour */ 202 struct svc_cred rq_cred; /* auth info */ 203 void * rq_xprt_ctxt; /* transport specific context ptr */ 204 struct svc_deferred_req*rq_deferred; /* deferred request we are replaying */ 205 206 struct xdr_buf rq_arg; 207 struct xdr_stream rq_arg_stream; 208 struct xdr_stream rq_res_stream; 209 struct page *rq_scratch_page; 210 struct xdr_buf rq_res; 211 struct page *rq_pages[RPCSVC_MAXPAGES + 1]; 212 struct page * *rq_respages; /* points into rq_pages */ 213 struct page * *rq_next_page; /* next reply page to use */ 214 struct page * *rq_page_end; /* one past the last page */ 215 216 struct folio_batch rq_fbatch; 217 struct kvec rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */ 218 struct bio_vec rq_bvec[RPCSVC_MAXPAGES]; 219 220 __be32 rq_xid; /* transmission id */ 221 u32 rq_prog; /* program number */ 222 u32 rq_vers; /* program version */ 223 u32 rq_proc; /* procedure number */ 224 u32 rq_prot; /* IP protocol */ 225 int rq_cachetype; /* catering to nfsd */ 226 unsigned long rq_flags; /* flags field */ 227 ktime_t rq_qtime; /* enqueue time */ 228 229 void * rq_argp; /* decoded arguments */ 230 void * rq_resp; /* xdr'd results */ 231 __be32 *rq_accept_statp; 232 void * rq_auth_data; /* flavor-specific data */ 233 __be32 rq_auth_stat; /* authentication status */ 234 int rq_auth_slack; /* extra space xdr code 235 * should leave in head 236 * for krb5i, krb5p. 237 */ 238 int rq_reserved; /* space on socket outq 239 * reserved for this request 240 */ 241 ktime_t rq_stime; /* start time */ 242 243 struct cache_req rq_chandle; /* handle passed to caches for 244 * request delaying 245 */ 246 /* Catering to nfsd */ 247 struct auth_domain * rq_client; /* RPC peer info */ 248 struct auth_domain * rq_gssclient; /* "gss/"-style peer info */ 249 struct task_struct *rq_task; /* service thread */ 250 struct net *rq_bc_net; /* pointer to backchannel's 251 * net namespace 252 */ 253 void ** rq_lease_breaker; /* The v4 client breaking a lease */ 254 unsigned int rq_status_counter; /* RPC processing counter */ 255 }; 256 257 /* bits for rq_flags */ 258 enum { 259 RQ_SECURE, /* secure port */ 260 RQ_LOCAL, /* local request */ 261 RQ_USEDEFERRAL, /* use deferral */ 262 RQ_DROPME, /* drop current reply */ 263 RQ_SPLICE_OK, /* turned off in gss privacy to prevent 264 * encrypting page cache pages */ 265 RQ_VICTIM, /* Have agreed to shut down */ 266 RQ_DATA, /* request has data */ 267 }; 268 269 #define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net) 270 271 /* 272 * Rigorous type checking on sockaddr type conversions 273 */ 274 static inline struct sockaddr_in *svc_addr_in(const struct svc_rqst *rqst) 275 { 276 return (struct sockaddr_in *) &rqst->rq_addr; 277 } 278 279 static inline struct sockaddr_in6 *svc_addr_in6(const struct svc_rqst *rqst) 280 { 281 return (struct sockaddr_in6 *) &rqst->rq_addr; 282 } 283 284 static inline struct sockaddr *svc_addr(const struct svc_rqst *rqst) 285 { 286 return (struct sockaddr *) &rqst->rq_addr; 287 } 288 289 static inline struct sockaddr_in *svc_daddr_in(const struct svc_rqst *rqst) 290 { 291 return (struct sockaddr_in *) &rqst->rq_daddr; 292 } 293 294 static inline struct sockaddr_in6 *svc_daddr_in6(const struct svc_rqst *rqst) 295 { 296 return (struct sockaddr_in6 *) &rqst->rq_daddr; 297 } 298 299 static inline struct sockaddr *svc_daddr(const struct svc_rqst *rqst) 300 { 301 return (struct sockaddr *) &rqst->rq_daddr; 302 } 303 304 /** 305 * svc_thread_should_stop - check if this thread should stop 306 * @rqstp: the thread that might need to stop 307 * 308 * To stop an svc thread, the pool flags SP_NEED_VICTIM and SP_VICTIM_REMAINS 309 * are set. The first thread which sees SP_NEED_VICTIM clears it, becoming 310 * the victim using this function. It should then promptly call 311 * svc_exit_thread() to complete the process, clearing SP_VICTIM_REMAINS 312 * so the task waiting for a thread to exit can wake and continue. 313 * 314 * Return values: 315 * %true: caller should invoke svc_exit_thread() 316 * %false: caller should do nothing 317 */ 318 static inline bool svc_thread_should_stop(struct svc_rqst *rqstp) 319 { 320 if (test_and_clear_bit(SP_NEED_VICTIM, &rqstp->rq_pool->sp_flags)) 321 set_bit(RQ_VICTIM, &rqstp->rq_flags); 322 323 return test_bit(RQ_VICTIM, &rqstp->rq_flags); 324 } 325 326 struct svc_deferred_req { 327 u32 prot; /* protocol (UDP or TCP) */ 328 struct svc_xprt *xprt; 329 struct sockaddr_storage addr; /* where reply must go */ 330 size_t addrlen; 331 struct sockaddr_storage daddr; /* where reply must come from */ 332 size_t daddrlen; 333 void *xprt_ctxt; 334 struct cache_deferred_req handle; 335 int argslen; 336 __be32 args[]; 337 }; 338 339 struct svc_process_info { 340 union { 341 int (*dispatch)(struct svc_rqst *rqstp); 342 struct { 343 unsigned int lovers; 344 unsigned int hivers; 345 } mismatch; 346 }; 347 }; 348 349 /* 350 * List of RPC programs on the same transport endpoint 351 */ 352 struct svc_program { 353 struct svc_program * pg_next; /* other programs (same xprt) */ 354 u32 pg_prog; /* program number */ 355 unsigned int pg_lovers; /* lowest version */ 356 unsigned int pg_hivers; /* highest version */ 357 unsigned int pg_nvers; /* number of versions */ 358 const struct svc_version **pg_vers; /* version array */ 359 char * pg_name; /* service name */ 360 char * pg_class; /* class name: services sharing authentication */ 361 struct svc_stat * pg_stats; /* rpc statistics */ 362 enum svc_auth_status (*pg_authenticate)(struct svc_rqst *rqstp); 363 __be32 (*pg_init_request)(struct svc_rqst *, 364 const struct svc_program *, 365 struct svc_process_info *); 366 int (*pg_rpcbind_set)(struct net *net, 367 const struct svc_program *, 368 u32 version, int family, 369 unsigned short proto, 370 unsigned short port); 371 }; 372 373 /* 374 * RPC program version 375 */ 376 struct svc_version { 377 u32 vs_vers; /* version number */ 378 u32 vs_nproc; /* number of procedures */ 379 const struct svc_procedure *vs_proc; /* per-procedure info */ 380 unsigned long __percpu *vs_count; /* call counts */ 381 u32 vs_xdrsize; /* xdrsize needed for this version */ 382 383 /* Don't register with rpcbind */ 384 bool vs_hidden; 385 386 /* Don't care if the rpcbind registration fails */ 387 bool vs_rpcb_optnl; 388 389 /* Need xprt with congestion control */ 390 bool vs_need_cong_ctrl; 391 392 /* Dispatch function */ 393 int (*vs_dispatch)(struct svc_rqst *rqstp); 394 }; 395 396 /* 397 * RPC procedure info 398 */ 399 struct svc_procedure { 400 /* process the request: */ 401 __be32 (*pc_func)(struct svc_rqst *); 402 /* XDR decode args: */ 403 bool (*pc_decode)(struct svc_rqst *rqstp, 404 struct xdr_stream *xdr); 405 /* XDR encode result: */ 406 bool (*pc_encode)(struct svc_rqst *rqstp, 407 struct xdr_stream *xdr); 408 /* XDR free result: */ 409 void (*pc_release)(struct svc_rqst *); 410 unsigned int pc_argsize; /* argument struct size */ 411 unsigned int pc_argzero; /* how much of argument to clear */ 412 unsigned int pc_ressize; /* result struct size */ 413 unsigned int pc_cachetype; /* cache info (NFS) */ 414 unsigned int pc_xdrressize; /* maximum size of XDR reply */ 415 const char * pc_name; /* for display */ 416 }; 417 418 /* 419 * Function prototypes. 420 */ 421 int svc_rpcb_setup(struct svc_serv *serv, struct net *net); 422 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net); 423 int svc_bind(struct svc_serv *serv, struct net *net); 424 struct svc_serv *svc_create(struct svc_program *, unsigned int, 425 int (*threadfn)(void *data)); 426 struct svc_rqst *svc_rqst_alloc(struct svc_serv *serv, 427 struct svc_pool *pool, int node); 428 bool svc_rqst_replace_page(struct svc_rqst *rqstp, 429 struct page *page); 430 void svc_rqst_release_pages(struct svc_rqst *rqstp); 431 void svc_rqst_free(struct svc_rqst *); 432 void svc_exit_thread(struct svc_rqst *); 433 struct svc_serv * svc_create_pooled(struct svc_program *, unsigned int, 434 int (*threadfn)(void *data)); 435 int svc_set_num_threads(struct svc_serv *, struct svc_pool *, int); 436 int svc_pool_stats_open(struct svc_serv *serv, struct file *file); 437 void svc_process(struct svc_rqst *rqstp); 438 void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp); 439 int svc_register(const struct svc_serv *, struct net *, const int, 440 const unsigned short, const unsigned short); 441 442 void svc_wake_up(struct svc_serv *); 443 void svc_reserve(struct svc_rqst *rqstp, int space); 444 void svc_pool_wake_idle_thread(struct svc_pool *pool); 445 struct svc_pool *svc_pool_for_cpu(struct svc_serv *serv); 446 char * svc_print_addr(struct svc_rqst *, char *, size_t); 447 const char * svc_proc_name(const struct svc_rqst *rqstp); 448 int svc_encode_result_payload(struct svc_rqst *rqstp, 449 unsigned int offset, 450 unsigned int length); 451 unsigned int svc_fill_write_vector(struct svc_rqst *rqstp, 452 struct xdr_buf *payload); 453 char *svc_fill_symlink_pathname(struct svc_rqst *rqstp, 454 struct kvec *first, void *p, 455 size_t total); 456 __be32 svc_generic_init_request(struct svc_rqst *rqstp, 457 const struct svc_program *progp, 458 struct svc_process_info *procinfo); 459 int svc_generic_rpcbind_set(struct net *net, 460 const struct svc_program *progp, 461 u32 version, int family, 462 unsigned short proto, 463 unsigned short port); 464 int svc_rpcbind_set_version(struct net *net, 465 const struct svc_program *progp, 466 u32 version, int family, 467 unsigned short proto, 468 unsigned short port); 469 470 #define RPC_MAX_ADDRBUFLEN (63U) 471 472 /* 473 * When we want to reduce the size of the reserved space in the response 474 * buffer, we need to take into account the size of any checksum data that 475 * may be at the end of the packet. This is difficult to determine exactly 476 * for all cases without actually generating the checksum, so we just use a 477 * static value. 478 */ 479 static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space) 480 { 481 svc_reserve(rqstp, space + rqstp->rq_auth_slack); 482 } 483 484 /** 485 * svcxdr_init_decode - Prepare an xdr_stream for Call decoding 486 * @rqstp: controlling server RPC transaction context 487 * 488 */ 489 static inline void svcxdr_init_decode(struct svc_rqst *rqstp) 490 { 491 struct xdr_stream *xdr = &rqstp->rq_arg_stream; 492 struct xdr_buf *buf = &rqstp->rq_arg; 493 struct kvec *argv = buf->head; 494 495 WARN_ON(buf->len != buf->head->iov_len + buf->page_len + buf->tail->iov_len); 496 buf->len = buf->head->iov_len + buf->page_len + buf->tail->iov_len; 497 498 xdr_init_decode(xdr, buf, argv->iov_base, NULL); 499 xdr_set_scratch_page(xdr, rqstp->rq_scratch_page); 500 } 501 502 /** 503 * svcxdr_init_encode - Prepare an xdr_stream for svc Reply encoding 504 * @rqstp: controlling server RPC transaction context 505 * 506 */ 507 static inline void svcxdr_init_encode(struct svc_rqst *rqstp) 508 { 509 struct xdr_stream *xdr = &rqstp->rq_res_stream; 510 struct xdr_buf *buf = &rqstp->rq_res; 511 struct kvec *resv = buf->head; 512 513 xdr_reset_scratch_buffer(xdr); 514 515 xdr->buf = buf; 516 xdr->iov = resv; 517 xdr->p = resv->iov_base + resv->iov_len; 518 xdr->end = resv->iov_base + PAGE_SIZE; 519 buf->len = resv->iov_len; 520 xdr->page_ptr = buf->pages - 1; 521 buf->buflen = PAGE_SIZE * (rqstp->rq_page_end - buf->pages); 522 xdr->rqst = NULL; 523 } 524 525 /** 526 * svcxdr_encode_opaque_pages - Insert pages into an xdr_stream 527 * @xdr: xdr_stream to be updated 528 * @pages: array of pages to insert 529 * @base: starting offset of first data byte in @pages 530 * @len: number of data bytes in @pages to insert 531 * 532 * After the @pages are added, the tail iovec is instantiated pointing 533 * to end of the head buffer, and the stream is set up to encode 534 * subsequent items into the tail. 535 */ 536 static inline void svcxdr_encode_opaque_pages(struct svc_rqst *rqstp, 537 struct xdr_stream *xdr, 538 struct page **pages, 539 unsigned int base, 540 unsigned int len) 541 { 542 xdr_write_pages(xdr, pages, base, len); 543 xdr->page_ptr = rqstp->rq_next_page - 1; 544 } 545 546 /** 547 * svcxdr_set_auth_slack - 548 * @rqstp: RPC transaction 549 * @slack: buffer space to reserve for the transaction's security flavor 550 * 551 * Set the request's slack space requirement, and set aside that much 552 * space in the rqstp's rq_res.head for use when the auth wraps the Reply. 553 */ 554 static inline void svcxdr_set_auth_slack(struct svc_rqst *rqstp, int slack) 555 { 556 struct xdr_stream *xdr = &rqstp->rq_res_stream; 557 struct xdr_buf *buf = &rqstp->rq_res; 558 struct kvec *resv = buf->head; 559 560 rqstp->rq_auth_slack = slack; 561 562 xdr->end -= XDR_QUADLEN(slack); 563 buf->buflen -= rqstp->rq_auth_slack; 564 565 WARN_ON(xdr->iov != resv); 566 WARN_ON(xdr->p > xdr->end); 567 } 568 569 /** 570 * svcxdr_set_accept_stat - Reserve space for the accept_stat field 571 * @rqstp: RPC transaction context 572 * 573 * Return values: 574 * %true: Success 575 * %false: No response buffer space was available 576 */ 577 static inline bool svcxdr_set_accept_stat(struct svc_rqst *rqstp) 578 { 579 struct xdr_stream *xdr = &rqstp->rq_res_stream; 580 581 rqstp->rq_accept_statp = xdr_reserve_space(xdr, XDR_UNIT); 582 if (unlikely(!rqstp->rq_accept_statp)) 583 return false; 584 *rqstp->rq_accept_statp = rpc_success; 585 return true; 586 } 587 588 #endif /* SUNRPC_SVC_H */ 589