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/lwq.h>
 21#include <linux/wait.h>
 22#include <linux/mm.h>
 23#include <linux/pagevec.h>
 24#include <linux/kthread.h>
 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 */
 36struct svc_pool {
 37	unsigned int		sp_id;		/* pool id; also node id on NUMA */
 38	struct lwq		sp_xprts;	/* pending transports */
 39	unsigned int		sp_nrthreads;	/* # of threads in pool */
 40	struct list_head	sp_all_threads;	/* all server threads */
 41	struct llist_head	sp_idle_threads; /* idle server threads */
 42
 43	/* statistics on pool operation */
 44	struct percpu_counter	sp_messages_arrived;
 45	struct percpu_counter	sp_sockets_queued;
 46	struct percpu_counter	sp_threads_woken;
 47
 48	unsigned long		sp_flags;
 49} ____cacheline_aligned_in_smp;
 50
 51/* bits for sp_flags */
 52enum {
 53	SP_TASK_PENDING,	/* still work to do even if no xprt is queued */
 54	SP_NEED_VICTIM,		/* One thread needs to agree to exit */
 55	SP_VICTIM_REMAINS,	/* One thread needs to actually exit */
 56};
 57
 58
 59/*
 60 * RPC service.
 61 *
 62 * An RPC service is a ``daemon,'' possibly multithreaded, which
 63 * receives and processes incoming RPC messages.
 64 * It has one or more transport sockets associated with it, and maintains
 65 * a list of idle threads waiting for input.
 66 *
 67 * We currently do not support more than one RPC program per daemon.
 68 */
 69struct svc_serv {
 70	struct svc_program *	sv_programs;	/* RPC programs */
 71	struct svc_stat *	sv_stats;	/* RPC statistics */
 72	spinlock_t		sv_lock;
 73	unsigned int		sv_nprogs;	/* Number of sv_programs */
 74	unsigned int		sv_nrthreads;	/* # of server threads */
 75	unsigned int		sv_max_payload;	/* datagram payload size */
 76	unsigned int		sv_max_mesg;	/* max_payload + 1 page for overheads */
 77	unsigned int		sv_xdrsize;	/* XDR buffer size */
 78	struct list_head	sv_permsocks;	/* all permanent sockets */
 79	struct list_head	sv_tempsocks;	/* all temporary sockets */
 80	int			sv_tmpcnt;	/* count of temporary "valid" sockets */
 81	struct timer_list	sv_temptimer;	/* timer for aging temporary sockets */
 82
 83	char *			sv_name;	/* service name */
 84
 85	unsigned int		sv_nrpools;	/* number of thread pools */
 86	bool			sv_is_pooled;	/* is this a pooled service? */
 87	struct svc_pool *	sv_pools;	/* array of thread pools */
 88	int			(*sv_threadfn)(void *data);
 89
 90#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 91	struct lwq		sv_cb_list;	/* queue for callback requests
 92						 * that arrive over the same
 93						 * connection */
 94	bool			sv_bc_enabled;	/* service uses backchannel */
 95#endif /* CONFIG_SUNRPC_BACKCHANNEL */
 96};
 97
 98/* This is used by pool_stats to find and lock an svc */
 99struct svc_info {
100	struct svc_serv		*serv;
101	struct mutex		*mutex;
102};
103
104void svc_destroy(struct svc_serv **svcp);
105
106/*
107 * Maximum payload size supported by a kernel RPC server.
108 * This is use to determine the max number of pages nfsd is
109 * willing to return in a single READ operation.
110 *
111 * These happen to all be powers of 2, which is not strictly
112 * necessary but helps enforce the real limitation, which is
113 * that they should be multiples of PAGE_SIZE.
114 *
115 * For UDP transports, a block plus NFS,RPC, and UDP headers
116 * has to fit into the IP datagram limit of 64K.  The largest
117 * feasible number for all known page sizes is probably 48K,
118 * but we choose 32K here.  This is the same as the historical
119 * Linux limit; someone who cares more about NFS/UDP performance
120 * can test a larger number.
121 *
122 * For non-UDP transports we have more freedom.  A size of 4MB is
123 * chosen to accommodate clients that support larger I/O sizes.
124 */
125enum {
126	RPCSVC_MAXPAYLOAD	= 4 * 1024 * 1024,
127	RPCSVC_MAXPAYLOAD_TCP	= RPCSVC_MAXPAYLOAD,
128	RPCSVC_MAXPAYLOAD_UDP	= 32 * 1024,
129};
130
131extern u32 svc_max_payload(const struct svc_rqst *rqstp);
132
133/*
134 * RPC Requests and replies are stored in one or more pages.
135 * We maintain an array of pages for each server thread.
136 * Requests are copied into these pages as they arrive.  Remaining
137 * pages are available to write the reply into.
138 *
139 * Pages are sent using ->sendmsg with MSG_SPLICE_PAGES so each server thread
140 * needs to allocate more to replace those used in sending.  To help keep track
141 * of these pages we have a receive list where all pages initialy live, and a
142 * send list where pages are moved to when there are to be part of a reply.
143 *
144 * We use xdr_buf for holding responses as it fits well with NFS
145 * read responses (that have a header, and some data pages, and possibly
146 * a tail) and means we can share some client side routines.
147 *
148 * The xdr_buf.head kvec always points to the first page in the rq_*pages
149 * list.  The xdr_buf.pages pointer points to the second page on that
150 * list.  xdr_buf.tail points to the end of the first page.
151 * This assumes that the non-page part of an rpc reply will fit
152 * in a page - NFSd ensures this.  lockd also has no trouble.
153 */
154
155/**
156 * svc_serv_maxpages - maximum count of pages needed for one RPC message
157 * @serv: RPC service context
158 *
159 * Returns a count of pages or vectors that can hold the maximum
160 * size RPC message for @serv.
161 *
162 * Each request/reply pair can have at most one "payload", plus two
163 * pages, one for the request, and one for the reply.
164 * nfsd_splice_actor() might need an extra page when a READ payload
165 * is not page-aligned.
166 */
167static inline unsigned long svc_serv_maxpages(const struct svc_serv *serv)
168{
169	return DIV_ROUND_UP(serv->sv_max_mesg, PAGE_SIZE) + 2 + 1;
170}
171
172/*
173 * The context of a single thread, including the request currently being
174 * processed.
175 */
176struct svc_rqst {
177	struct list_head	rq_all;		/* all threads list */
178	struct llist_node	rq_idle;	/* On the idle list */
179	struct rcu_head		rq_rcu_head;	/* for RCU deferred kfree */
180	struct svc_xprt *	rq_xprt;	/* transport ptr */
181
182	struct sockaddr_storage	rq_addr;	/* peer address */
183	size_t			rq_addrlen;
184	struct sockaddr_storage	rq_daddr;	/* dest addr of request
185						 *  - reply from here */
186	size_t			rq_daddrlen;
187
188	struct svc_serv *	rq_server;	/* RPC service definition */
189	struct svc_pool *	rq_pool;	/* thread pool */
190	const struct svc_procedure *rq_procinfo;/* procedure info */
191	struct auth_ops *	rq_authop;	/* authentication flavour */
192	struct svc_cred		rq_cred;	/* auth info */
193	void *			rq_xprt_ctxt;	/* transport specific context ptr */
194	struct svc_deferred_req*rq_deferred;	/* deferred request we are replaying */
195
196	struct xdr_buf		rq_arg;
197	struct xdr_stream	rq_arg_stream;
198	struct xdr_stream	rq_res_stream;
199	struct folio		*rq_scratch_folio;
200	struct xdr_buf		rq_res;
201	unsigned long		rq_maxpages;	/* num of entries in rq_pages */
202	struct page *		*rq_pages;
203	struct page *		*rq_respages;	/* points into rq_pages */
204	struct page *		*rq_next_page; /* next reply page to use */
205	struct page *		*rq_page_end;  /* one past the last page */
206
207	struct folio_batch	rq_fbatch;
208	struct bio_vec		*rq_bvec;
209
210	__be32			rq_xid;		/* transmission id */
211	u32			rq_prog;	/* program number */
212	u32			rq_vers;	/* program version */
213	u32			rq_proc;	/* procedure number */
214	u32			rq_prot;	/* IP protocol */
215	int			rq_cachetype;	/* catering to nfsd */
216	unsigned long		rq_flags;	/* flags field */
217	ktime_t			rq_qtime;	/* enqueue time */
218
219	void *			rq_argp;	/* decoded arguments */
220	void *			rq_resp;	/* xdr'd results */
221	__be32			*rq_accept_statp;
222	void *			rq_auth_data;	/* flavor-specific data */
223	__be32			rq_auth_stat;	/* authentication status */
224	int			rq_auth_slack;	/* extra space xdr code
225						 * should leave in head
226						 * for krb5i, krb5p.
227						 */
228	int			rq_reserved;	/* space on socket outq
229						 * reserved for this request
230						 */
231	ktime_t			rq_stime;	/* start time */
232
233	struct cache_req	rq_chandle;	/* handle passed to caches for 
234						 * request delaying 
235						 */
236	/* Catering to nfsd */
237	struct auth_domain *	rq_client;	/* RPC peer info */
238	struct auth_domain *	rq_gssclient;	/* "gss/"-style peer info */
239	struct task_struct	*rq_task;	/* service thread */
240	struct net		*rq_bc_net;	/* pointer to backchannel's
241						 * net namespace
242						 */
243
244	int			rq_err;		/* Thread sets this to inidicate
245						 * initialisation success.
246						 */
247
248	unsigned long		bc_to_initval;
249	unsigned int		bc_to_retries;
250	unsigned int		rq_status_counter; /* RPC processing counter */
251	void			**rq_lease_breaker; /* The v4 client breaking a lease */
252};
253
254/* bits for rq_flags */
255enum {
256	RQ_SECURE,		/* secure port */
257	RQ_LOCAL,		/* local request */
258	RQ_USEDEFERRAL,		/* use deferral */
259	RQ_DROPME,		/* drop current reply */
260	RQ_VICTIM,		/* Have agreed to shut down */
261	RQ_DATA,		/* request has data */
262};
263
264#define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net)
265
266/*
267 * Rigorous type checking on sockaddr type conversions
268 */
269static inline struct sockaddr_in *svc_addr_in(const struct svc_rqst *rqst)
270{
271	return (struct sockaddr_in *) &rqst->rq_addr;
272}
273
274static inline struct sockaddr_in6 *svc_addr_in6(const struct svc_rqst *rqst)
275{
276	return (struct sockaddr_in6 *) &rqst->rq_addr;
277}
278
279static inline struct sockaddr *svc_addr(const struct svc_rqst *rqst)
280{
281	return (struct sockaddr *) &rqst->rq_addr;
282}
283
284static inline struct sockaddr_in *svc_daddr_in(const struct svc_rqst *rqst)
285{
286	return (struct sockaddr_in *) &rqst->rq_daddr;
287}
288
289static inline struct sockaddr_in6 *svc_daddr_in6(const struct svc_rqst *rqst)
290{
291	return (struct sockaddr_in6 *) &rqst->rq_daddr;
292}
293
294static inline struct sockaddr *svc_daddr(const struct svc_rqst *rqst)
295{
296	return (struct sockaddr *) &rqst->rq_daddr;
297}
298
299/**
300 * svc_thread_should_stop - check if this thread should stop
301 * @rqstp: the thread that might need to stop
302 *
303 * To stop an svc thread, the pool flags SP_NEED_VICTIM and SP_VICTIM_REMAINS
304 * are set.  The first thread which sees SP_NEED_VICTIM clears it, becoming
305 * the victim using this function.  It should then promptly call
306 * svc_exit_thread() to complete the process, clearing SP_VICTIM_REMAINS
307 * so the task waiting for a thread to exit can wake and continue.
308 *
309 * Return values:
310 *   %true: caller should invoke svc_exit_thread()
311 *   %false: caller should do nothing
312 */
313static inline bool svc_thread_should_stop(struct svc_rqst *rqstp)
314{
315	if (test_and_clear_bit(SP_NEED_VICTIM, &rqstp->rq_pool->sp_flags))
316		set_bit(RQ_VICTIM, &rqstp->rq_flags);
317
318	return test_bit(RQ_VICTIM, &rqstp->rq_flags);
319}
320
321/**
322 * svc_thread_init_status - report whether thread has initialised successfully
323 * @rqstp: the thread in question
324 * @err: errno code
325 *
326 * After performing any initialisation that could fail, and before starting
327 * normal work, each sunrpc svc_thread must call svc_thread_init_status()
328 * with an appropriate error, or zero.
329 *
330 * If zero is passed, the thread is ready and must continue until
331 * svc_thread_should_stop() returns true.  If a non-zero error is passed
332 * the call will not return - the thread will exit.
333 */
334static inline void svc_thread_init_status(struct svc_rqst *rqstp, int err)
335{
336	store_release_wake_up(&rqstp->rq_err, err);
337	if (err)
338		kthread_exit(1);
339}
340
341struct svc_deferred_req {
342	u32			prot;	/* protocol (UDP or TCP) */
343	struct svc_xprt		*xprt;
344	struct sockaddr_storage	addr;	/* where reply must go */
345	size_t			addrlen;
346	struct sockaddr_storage	daddr;	/* where reply must come from */
347	size_t			daddrlen;
348	void			*xprt_ctxt;
349	struct cache_deferred_req handle;
350	int			argslen;
351	__be32			args[];
352};
353
354struct svc_process_info {
355	union {
356		int  (*dispatch)(struct svc_rqst *rqstp);
357		struct {
358			unsigned int lovers;
359			unsigned int hivers;
360		} mismatch;
361	};
362};
363
364/*
365 * RPC program - an array of these can use the same transport endpoint
366 */
367struct svc_program {
368	u32			pg_prog;	/* program number */
369	unsigned int		pg_lovers;	/* lowest version */
370	unsigned int		pg_hivers;	/* highest version */
371	unsigned int		pg_nvers;	/* number of versions */
372	const struct svc_version **pg_vers;	/* version array */
373	char *			pg_name;	/* service name */
374	char *			pg_class;	/* class name: services sharing authentication */
375	enum svc_auth_status	(*pg_authenticate)(struct svc_rqst *rqstp);
376	__be32			(*pg_init_request)(struct svc_rqst *,
377						   const struct svc_program *,
378						   struct svc_process_info *);
379	int			(*pg_rpcbind_set)(struct net *net,
380						  const struct svc_program *,
381						  u32 version, int family,
382						  unsigned short proto,
383						  unsigned short port);
384};
385
386/*
387 * RPC program version
388 */
389struct svc_version {
390	u32			vs_vers;	/* version number */
391	u32			vs_nproc;	/* number of procedures */
392	const struct svc_procedure *vs_proc;	/* per-procedure info */
393	unsigned long __percpu	*vs_count;	/* call counts */
394	u32			vs_xdrsize;	/* xdrsize needed for this version */
395
396	/* Don't register with rpcbind */
397	bool			vs_hidden;
398
399	/* Don't care if the rpcbind registration fails */
400	bool			vs_rpcb_optnl;
401
402	/* Need xprt with congestion control */
403	bool			vs_need_cong_ctrl;
404
405	/* Dispatch function */
406	int			(*vs_dispatch)(struct svc_rqst *rqstp);
407};
408
409/*
410 * RPC procedure info
411 */
412struct svc_procedure {
413	/* process the request: */
414	__be32			(*pc_func)(struct svc_rqst *);
415	/* XDR decode args: */
416	bool			(*pc_decode)(struct svc_rqst *rqstp,
417					     struct xdr_stream *xdr);
418	/* XDR encode result: */
419	bool			(*pc_encode)(struct svc_rqst *rqstp,
420					     struct xdr_stream *xdr);
421	/* XDR free result: */
422	void			(*pc_release)(struct svc_rqst *);
423	unsigned int		pc_argsize;	/* argument struct size */
424	unsigned int		pc_argzero;	/* how much of argument to clear */
425	unsigned int		pc_ressize;	/* result struct size */
426	unsigned int		pc_cachetype;	/* cache info (NFS) */
427	unsigned int		pc_xdrressize;	/* maximum size of XDR reply */
428	const char *		pc_name;	/* for display */
429};
430
431/*
432 * Function prototypes.
433 */
434int sunrpc_set_pool_mode(const char *val);
435int sunrpc_get_pool_mode(char *val, size_t size);
436void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net);
437int svc_bind(struct svc_serv *serv, struct net *net);
438struct svc_serv *svc_create(struct svc_program *, unsigned int,
439			    int (*threadfn)(void *data));
440bool		   svc_rqst_replace_page(struct svc_rqst *rqstp,
441					 struct page *page);
442void		   svc_rqst_release_pages(struct svc_rqst *rqstp);
443void		   svc_exit_thread(struct svc_rqst *);
444struct svc_serv *  svc_create_pooled(struct svc_program *prog,
445				     unsigned int nprog,
446				     struct svc_stat *stats,
447				     unsigned int bufsize,
448				     int (*threadfn)(void *data));
449int		   svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
450int		   svc_pool_stats_open(struct svc_info *si, struct file *file);
451void		   svc_process(struct svc_rqst *rqstp);
452void		   svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp);
453int		   svc_register(const struct svc_serv *, struct net *, const int,
454				const unsigned short, const unsigned short);
455
456void		   svc_wake_up(struct svc_serv *);
457void		   svc_reserve(struct svc_rqst *rqstp, int space);
458void		   svc_pool_wake_idle_thread(struct svc_pool *pool);
459struct svc_pool   *svc_pool_for_cpu(struct svc_serv *serv);
460char *		   svc_print_addr(struct svc_rqst *, char *, size_t);
461const char *	   svc_proc_name(const struct svc_rqst *rqstp);
462int		   svc_encode_result_payload(struct svc_rqst *rqstp,
463					     unsigned int offset,
464					     unsigned int length);
465char		  *svc_fill_symlink_pathname(struct svc_rqst *rqstp,
466					     struct kvec *first, void *p,
467					     size_t total);
468__be32		   svc_generic_init_request(struct svc_rqst *rqstp,
469					    const struct svc_program *progp,
470					    struct svc_process_info *procinfo);
471int		   svc_generic_rpcbind_set(struct net *net,
472					   const struct svc_program *progp,
473					   u32 version, int family,
474					   unsigned short proto,
475					   unsigned short port);
476
477#define	RPC_MAX_ADDRBUFLEN	(63U)
478
479/*
480 * When we want to reduce the size of the reserved space in the response
481 * buffer, we need to take into account the size of any checksum data that
482 * may be at the end of the packet. This is difficult to determine exactly
483 * for all cases without actually generating the checksum, so we just use a
484 * static value.
485 */
486static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space)
487{
488	svc_reserve(rqstp, space + rqstp->rq_auth_slack);
489}
490
491/**
492 * svcxdr_init_decode - Prepare an xdr_stream for Call decoding
493 * @rqstp: controlling server RPC transaction context
494 *
495 */
496static inline void svcxdr_init_decode(struct svc_rqst *rqstp)
497{
498	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
499	struct xdr_buf *buf = &rqstp->rq_arg;
500	struct kvec *argv = buf->head;
501
502	WARN_ON(buf->len != buf->head->iov_len + buf->page_len + buf->tail->iov_len);
503	buf->len = buf->head->iov_len + buf->page_len + buf->tail->iov_len;
504
505	xdr_init_decode(xdr, buf, argv->iov_base, NULL);
506	xdr_set_scratch_folio(xdr, rqstp->rq_scratch_folio);
507}
508
509/**
510 * svcxdr_init_encode - Prepare an xdr_stream for svc Reply encoding
511 * @rqstp: controlling server RPC transaction context
512 *
513 */
514static inline void svcxdr_init_encode(struct svc_rqst *rqstp)
515{
516	struct xdr_stream *xdr = &rqstp->rq_res_stream;
517	struct xdr_buf *buf = &rqstp->rq_res;
518	struct kvec *resv = buf->head;
519
520	xdr_reset_scratch_buffer(xdr);
521
522	xdr->buf = buf;
523	xdr->iov = resv;
524	xdr->p   = resv->iov_base + resv->iov_len;
525	xdr->end = resv->iov_base + PAGE_SIZE;
526	buf->len = resv->iov_len;
527	xdr->page_ptr = buf->pages - 1;
528	buf->buflen = PAGE_SIZE * (rqstp->rq_page_end - buf->pages);
529	xdr->rqst = NULL;
530}
531
532/**
533 * svcxdr_encode_opaque_pages - Insert pages into an xdr_stream
534 * @xdr: xdr_stream to be updated
535 * @pages: array of pages to insert
536 * @base: starting offset of first data byte in @pages
537 * @len: number of data bytes in @pages to insert
538 *
539 * After the @pages are added, the tail iovec is instantiated pointing
540 * to end of the head buffer, and the stream is set up to encode
541 * subsequent items into the tail.
542 */
543static inline void svcxdr_encode_opaque_pages(struct svc_rqst *rqstp,
544					      struct xdr_stream *xdr,
545					      struct page **pages,
546					      unsigned int base,
547					      unsigned int len)
548{
549	xdr_write_pages(xdr, pages, base, len);
550	xdr->page_ptr = rqstp->rq_next_page - 1;
551}
552
553/**
554 * svcxdr_set_auth_slack -
555 * @rqstp: RPC transaction
556 * @slack: buffer space to reserve for the transaction's security flavor
557 *
558 * Set the request's slack space requirement, and set aside that much
559 * space in the rqstp's rq_res.head for use when the auth wraps the Reply.
560 */
561static inline void svcxdr_set_auth_slack(struct svc_rqst *rqstp, int slack)
562{
563	struct xdr_stream *xdr = &rqstp->rq_res_stream;
564	struct xdr_buf *buf = &rqstp->rq_res;
565	struct kvec *resv = buf->head;
566
567	rqstp->rq_auth_slack = slack;
568
569	xdr->end -= XDR_QUADLEN(slack);
570	buf->buflen -= rqstp->rq_auth_slack;
571
572	WARN_ON(xdr->iov != resv);
573	WARN_ON(xdr->p > xdr->end);
574}
575
576/**
577 * svcxdr_set_accept_stat - Reserve space for the accept_stat field
578 * @rqstp: RPC transaction context
579 *
580 * Return values:
581 *   %true: Success
582 *   %false: No response buffer space was available
583 */
584static inline bool svcxdr_set_accept_stat(struct svc_rqst *rqstp)
585{
586	struct xdr_stream *xdr = &rqstp->rq_res_stream;
587
588	rqstp->rq_accept_statp = xdr_reserve_space(xdr, XDR_UNIT);
589	if (unlikely(!rqstp->rq_accept_statp))
590		return false;
591	*rqstp->rq_accept_statp = rpc_success;
592	return true;
593}
594
595#endif /* SUNRPC_SVC_H */