xref: /linux/fs/lockd/svc.c (revision c1f3caff2450048ab6c053e5b23698b58f286159)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * linux/fs/lockd/svc.c
4  *
5  * This is the central lockd service.
6  *
7  * FIXME: Separate the lockd NFS server functionality from the lockd NFS
8  * 	  client functionality. Oh why didn't Sun create two separate
9  *	  services in the first place?
10  *
11  * Authors:	Olaf Kirch (okir@monad.swb.de)
12  *
13  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
14  */
15 
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/sysctl.h>
19 #include <linux/moduleparam.h>
20 
21 #include <linux/sched/signal.h>
22 #include <linux/errno.h>
23 #include <linux/in.h>
24 #include <linux/uio.h>
25 #include <linux/smp.h>
26 #include <linux/mutex.h>
27 #include <linux/kthread.h>
28 #include <linux/freezer.h>
29 #include <linux/inetdevice.h>
30 
31 #include <linux/sunrpc/types.h>
32 #include <linux/sunrpc/stats.h>
33 #include <linux/sunrpc/clnt.h>
34 #include <linux/sunrpc/svc.h>
35 #include <linux/sunrpc/svcsock.h>
36 #include <linux/sunrpc/svc_xprt.h>
37 #include <net/ip.h>
38 #include <net/addrconf.h>
39 #include <net/ipv6.h>
40 #include <linux/lockd/lockd.h>
41 #include <linux/nfs.h>
42 
43 #include "netns.h"
44 #include "procfs.h"
45 
46 #define NLMDBG_FACILITY		NLMDBG_SVC
47 #define LOCKD_BUFSIZE		(1024 + NLMSVC_XDRSIZE)
48 #define ALLOWED_SIGS		(sigmask(SIGKILL))
49 
50 static struct svc_program	nlmsvc_program;
51 
52 const struct nlmsvc_binding	*nlmsvc_ops;
53 EXPORT_SYMBOL_GPL(nlmsvc_ops);
54 
55 static DEFINE_MUTEX(nlmsvc_mutex);
56 static unsigned int		nlmsvc_users;
57 static struct svc_serv		*nlmsvc_serv;
58 unsigned long			nlmsvc_timeout;
59 
60 unsigned int lockd_net_id;
61 
62 /*
63  * These can be set at insmod time (useful for NFS as root filesystem),
64  * and also changed through the sysctl interface.  -- Jamie Lokier, Aug 2003
65  */
66 static unsigned long		nlm_grace_period;
67 static unsigned long		nlm_timeout = LOCKD_DFLT_TIMEO;
68 static int			nlm_udpport, nlm_tcpport;
69 
70 /* RLIM_NOFILE defaults to 1024. That seems like a reasonable default here. */
71 static unsigned int		nlm_max_connections = 1024;
72 
73 /*
74  * Constants needed for the sysctl interface.
75  */
76 static const unsigned long	nlm_grace_period_min = 0;
77 static const unsigned long	nlm_grace_period_max = 240;
78 static const unsigned long	nlm_timeout_min = 3;
79 static const unsigned long	nlm_timeout_max = 20;
80 static const int		nlm_port_min = 0, nlm_port_max = 65535;
81 
82 #ifdef CONFIG_SYSCTL
83 static struct ctl_table_header * nlm_sysctl_table;
84 #endif
85 
86 static unsigned long get_lockd_grace_period(void)
87 {
88 	/* Note: nlm_timeout should always be nonzero */
89 	if (nlm_grace_period)
90 		return roundup(nlm_grace_period, nlm_timeout) * HZ;
91 	else
92 		return nlm_timeout * 5 * HZ;
93 }
94 
95 static void grace_ender(struct work_struct *grace)
96 {
97 	struct delayed_work *dwork = to_delayed_work(grace);
98 	struct lockd_net *ln = container_of(dwork, struct lockd_net,
99 					    grace_period_end);
100 
101 	locks_end_grace(&ln->lockd_manager);
102 }
103 
104 static void set_grace_period(struct net *net)
105 {
106 	unsigned long grace_period = get_lockd_grace_period();
107 	struct lockd_net *ln = net_generic(net, lockd_net_id);
108 
109 	locks_start_grace(net, &ln->lockd_manager);
110 	cancel_delayed_work_sync(&ln->grace_period_end);
111 	schedule_delayed_work(&ln->grace_period_end, grace_period);
112 }
113 
114 static void restart_grace(void)
115 {
116 	if (nlmsvc_ops) {
117 		struct net *net = &init_net;
118 		struct lockd_net *ln = net_generic(net, lockd_net_id);
119 
120 		cancel_delayed_work_sync(&ln->grace_period_end);
121 		locks_end_grace(&ln->lockd_manager);
122 		nlmsvc_invalidate_all();
123 		set_grace_period(net);
124 	}
125 }
126 
127 /*
128  * This is the lockd kernel thread
129  */
130 static int
131 lockd(void *vrqstp)
132 {
133 	int		err = 0;
134 	struct svc_rqst *rqstp = vrqstp;
135 	struct net *net = &init_net;
136 	struct lockd_net *ln = net_generic(net, lockd_net_id);
137 
138 	/* try_to_freeze() is called from svc_recv() */
139 	set_freezable();
140 
141 	/* Allow SIGKILL to tell lockd to drop all of its locks */
142 	allow_signal(SIGKILL);
143 
144 	dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
145 
146 	/*
147 	 * The main request loop. We don't terminate until the last
148 	 * NFS mount or NFS daemon has gone away.
149 	 */
150 	while (!kthread_should_stop()) {
151 		long timeout = MAX_SCHEDULE_TIMEOUT;
152 		RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
153 
154 		/* update sv_maxconn if it has changed */
155 		rqstp->rq_server->sv_maxconn = nlm_max_connections;
156 
157 		if (signalled()) {
158 			flush_signals(current);
159 			restart_grace();
160 			continue;
161 		}
162 
163 		timeout = nlmsvc_retry_blocked();
164 
165 		/*
166 		 * Find a socket with data available and call its
167 		 * recvfrom routine.
168 		 */
169 		err = svc_recv(rqstp, timeout);
170 		if (err == -EAGAIN || err == -EINTR)
171 			continue;
172 		dprintk("lockd: request from %s\n",
173 				svc_print_addr(rqstp, buf, sizeof(buf)));
174 
175 		svc_process(rqstp);
176 	}
177 	flush_signals(current);
178 	if (nlmsvc_ops)
179 		nlmsvc_invalidate_all();
180 	nlm_shutdown_hosts();
181 	cancel_delayed_work_sync(&ln->grace_period_end);
182 	locks_end_grace(&ln->lockd_manager);
183 
184 	dprintk("lockd_down: service stopped\n");
185 
186 	svc_exit_thread(rqstp);
187 
188 	module_put_and_kthread_exit(0);
189 }
190 
191 static int create_lockd_listener(struct svc_serv *serv, const char *name,
192 				 struct net *net, const int family,
193 				 const unsigned short port,
194 				 const struct cred *cred)
195 {
196 	struct svc_xprt *xprt;
197 
198 	xprt = svc_find_xprt(serv, name, net, family, 0);
199 	if (xprt == NULL)
200 		return svc_create_xprt(serv, name, net, family, port,
201 						SVC_SOCK_DEFAULTS, cred);
202 	svc_xprt_put(xprt);
203 	return 0;
204 }
205 
206 static int create_lockd_family(struct svc_serv *serv, struct net *net,
207 			       const int family, const struct cred *cred)
208 {
209 	int err;
210 
211 	err = create_lockd_listener(serv, "udp", net, family, nlm_udpport,
212 			cred);
213 	if (err < 0)
214 		return err;
215 
216 	return create_lockd_listener(serv, "tcp", net, family, nlm_tcpport,
217 			cred);
218 }
219 
220 /*
221  * Ensure there are active UDP and TCP listeners for lockd.
222  *
223  * Even if we have only TCP NFS mounts and/or TCP NFSDs, some
224  * local services (such as rpc.statd) still require UDP, and
225  * some NFS servers do not yet support NLM over TCP.
226  *
227  * Returns zero if all listeners are available; otherwise a
228  * negative errno value is returned.
229  */
230 static int make_socks(struct svc_serv *serv, struct net *net,
231 		const struct cred *cred)
232 {
233 	static int warned;
234 	int err;
235 
236 	err = create_lockd_family(serv, net, PF_INET, cred);
237 	if (err < 0)
238 		goto out_err;
239 
240 	err = create_lockd_family(serv, net, PF_INET6, cred);
241 	if (err < 0 && err != -EAFNOSUPPORT)
242 		goto out_err;
243 
244 	warned = 0;
245 	return 0;
246 
247 out_err:
248 	if (warned++ == 0)
249 		printk(KERN_WARNING
250 			"lockd_up: makesock failed, error=%d\n", err);
251 	svc_shutdown_net(serv, net);
252 	return err;
253 }
254 
255 static int lockd_up_net(struct svc_serv *serv, struct net *net,
256 		const struct cred *cred)
257 {
258 	struct lockd_net *ln = net_generic(net, lockd_net_id);
259 	int error;
260 
261 	if (ln->nlmsvc_users++)
262 		return 0;
263 
264 	error = svc_bind(serv, net);
265 	if (error)
266 		goto err_bind;
267 
268 	error = make_socks(serv, net, cred);
269 	if (error < 0)
270 		goto err_bind;
271 	set_grace_period(net);
272 	dprintk("%s: per-net data created; net=%x\n", __func__, net->ns.inum);
273 	return 0;
274 
275 err_bind:
276 	ln->nlmsvc_users--;
277 	return error;
278 }
279 
280 static void lockd_down_net(struct svc_serv *serv, struct net *net)
281 {
282 	struct lockd_net *ln = net_generic(net, lockd_net_id);
283 
284 	if (ln->nlmsvc_users) {
285 		if (--ln->nlmsvc_users == 0) {
286 			nlm_shutdown_hosts_net(net);
287 			cancel_delayed_work_sync(&ln->grace_period_end);
288 			locks_end_grace(&ln->lockd_manager);
289 			svc_shutdown_net(serv, net);
290 			dprintk("%s: per-net data destroyed; net=%x\n",
291 				__func__, net->ns.inum);
292 		}
293 	} else {
294 		pr_err("%s: no users! net=%x\n",
295 			__func__, net->ns.inum);
296 		BUG();
297 	}
298 }
299 
300 static int lockd_inetaddr_event(struct notifier_block *this,
301 	unsigned long event, void *ptr)
302 {
303 	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
304 	struct sockaddr_in sin;
305 
306 	if (event != NETDEV_DOWN)
307 		goto out;
308 
309 	if (nlmsvc_serv) {
310 		dprintk("lockd_inetaddr_event: removed %pI4\n",
311 			&ifa->ifa_local);
312 		sin.sin_family = AF_INET;
313 		sin.sin_addr.s_addr = ifa->ifa_local;
314 		svc_age_temp_xprts_now(nlmsvc_serv, (struct sockaddr *)&sin);
315 	}
316 
317 out:
318 	return NOTIFY_DONE;
319 }
320 
321 static struct notifier_block lockd_inetaddr_notifier = {
322 	.notifier_call = lockd_inetaddr_event,
323 };
324 
325 #if IS_ENABLED(CONFIG_IPV6)
326 static int lockd_inet6addr_event(struct notifier_block *this,
327 	unsigned long event, void *ptr)
328 {
329 	struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr;
330 	struct sockaddr_in6 sin6;
331 
332 	if (event != NETDEV_DOWN)
333 		goto out;
334 
335 	if (nlmsvc_serv) {
336 		dprintk("lockd_inet6addr_event: removed %pI6\n", &ifa->addr);
337 		sin6.sin6_family = AF_INET6;
338 		sin6.sin6_addr = ifa->addr;
339 		if (ipv6_addr_type(&sin6.sin6_addr) & IPV6_ADDR_LINKLOCAL)
340 			sin6.sin6_scope_id = ifa->idev->dev->ifindex;
341 		svc_age_temp_xprts_now(nlmsvc_serv, (struct sockaddr *)&sin6);
342 	}
343 
344 out:
345 	return NOTIFY_DONE;
346 }
347 
348 static struct notifier_block lockd_inet6addr_notifier = {
349 	.notifier_call = lockd_inet6addr_event,
350 };
351 #endif
352 
353 static const struct svc_serv_ops lockd_sv_ops = {
354 	.svo_shutdown		= svc_rpcb_cleanup,
355 	.svo_function		= lockd,
356 	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
357 	.svo_module		= THIS_MODULE,
358 };
359 
360 static int lockd_get(void)
361 {
362 	struct svc_serv *serv;
363 	int error;
364 
365 	if (nlmsvc_serv) {
366 		svc_get(nlmsvc_serv);
367 		nlmsvc_users++;
368 		return 0;
369 	}
370 
371 	/*
372 	 * Sanity check: if there's no pid,
373 	 * we should be the first user ...
374 	 */
375 	if (nlmsvc_users)
376 		printk(KERN_WARNING
377 			"lockd_up: no pid, %d users??\n", nlmsvc_users);
378 
379 	if (!nlm_timeout)
380 		nlm_timeout = LOCKD_DFLT_TIMEO;
381 	nlmsvc_timeout = nlm_timeout * HZ;
382 
383 	serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, &lockd_sv_ops);
384 	if (!serv) {
385 		printk(KERN_WARNING "lockd_up: create service failed\n");
386 		return -ENOMEM;
387 	}
388 
389 	serv->sv_maxconn = nlm_max_connections;
390 	error = svc_set_num_threads(serv, NULL, 1);
391 	/* The thread now holds the only reference */
392 	svc_put(serv);
393 	if (error < 0)
394 		return error;
395 
396 	nlmsvc_serv = serv;
397 	register_inetaddr_notifier(&lockd_inetaddr_notifier);
398 #if IS_ENABLED(CONFIG_IPV6)
399 	register_inet6addr_notifier(&lockd_inet6addr_notifier);
400 #endif
401 	dprintk("lockd_up: service created\n");
402 	nlmsvc_users++;
403 	return 0;
404 }
405 
406 static void lockd_put(void)
407 {
408 	if (WARN(nlmsvc_users <= 0, "lockd_down: no users!\n"))
409 		return;
410 	if (--nlmsvc_users)
411 		return;
412 
413 	unregister_inetaddr_notifier(&lockd_inetaddr_notifier);
414 #if IS_ENABLED(CONFIG_IPV6)
415 	unregister_inet6addr_notifier(&lockd_inet6addr_notifier);
416 #endif
417 
418 	svc_set_num_threads(nlmsvc_serv, NULL, 0);
419 	nlmsvc_serv = NULL;
420 	dprintk("lockd_down: service destroyed\n");
421 }
422 
423 /*
424  * Bring up the lockd process if it's not already up.
425  */
426 int lockd_up(struct net *net, const struct cred *cred)
427 {
428 	int error;
429 
430 	mutex_lock(&nlmsvc_mutex);
431 
432 	error = lockd_get();
433 	if (error)
434 		goto err;
435 
436 	error = lockd_up_net(nlmsvc_serv, net, cred);
437 	if (error < 0) {
438 		lockd_put();
439 		goto err;
440 	}
441 
442 err:
443 	mutex_unlock(&nlmsvc_mutex);
444 	return error;
445 }
446 EXPORT_SYMBOL_GPL(lockd_up);
447 
448 /*
449  * Decrement the user count and bring down lockd if we're the last.
450  */
451 void
452 lockd_down(struct net *net)
453 {
454 	mutex_lock(&nlmsvc_mutex);
455 	lockd_down_net(nlmsvc_serv, net);
456 	lockd_put();
457 	mutex_unlock(&nlmsvc_mutex);
458 }
459 EXPORT_SYMBOL_GPL(lockd_down);
460 
461 #ifdef CONFIG_SYSCTL
462 
463 /*
464  * Sysctl parameters (same as module parameters, different interface).
465  */
466 
467 static struct ctl_table nlm_sysctls[] = {
468 	{
469 		.procname	= "nlm_grace_period",
470 		.data		= &nlm_grace_period,
471 		.maxlen		= sizeof(unsigned long),
472 		.mode		= 0644,
473 		.proc_handler	= proc_doulongvec_minmax,
474 		.extra1		= (unsigned long *) &nlm_grace_period_min,
475 		.extra2		= (unsigned long *) &nlm_grace_period_max,
476 	},
477 	{
478 		.procname	= "nlm_timeout",
479 		.data		= &nlm_timeout,
480 		.maxlen		= sizeof(unsigned long),
481 		.mode		= 0644,
482 		.proc_handler	= proc_doulongvec_minmax,
483 		.extra1		= (unsigned long *) &nlm_timeout_min,
484 		.extra2		= (unsigned long *) &nlm_timeout_max,
485 	},
486 	{
487 		.procname	= "nlm_udpport",
488 		.data		= &nlm_udpport,
489 		.maxlen		= sizeof(int),
490 		.mode		= 0644,
491 		.proc_handler	= proc_dointvec_minmax,
492 		.extra1		= (int *) &nlm_port_min,
493 		.extra2		= (int *) &nlm_port_max,
494 	},
495 	{
496 		.procname	= "nlm_tcpport",
497 		.data		= &nlm_tcpport,
498 		.maxlen		= sizeof(int),
499 		.mode		= 0644,
500 		.proc_handler	= proc_dointvec_minmax,
501 		.extra1		= (int *) &nlm_port_min,
502 		.extra2		= (int *) &nlm_port_max,
503 	},
504 	{
505 		.procname	= "nsm_use_hostnames",
506 		.data		= &nsm_use_hostnames,
507 		.maxlen		= sizeof(int),
508 		.mode		= 0644,
509 		.proc_handler	= proc_dobool,
510 	},
511 	{
512 		.procname	= "nsm_local_state",
513 		.data		= &nsm_local_state,
514 		.maxlen		= sizeof(int),
515 		.mode		= 0644,
516 		.proc_handler	= proc_dointvec,
517 	},
518 	{ }
519 };
520 
521 static struct ctl_table nlm_sysctl_dir[] = {
522 	{
523 		.procname	= "nfs",
524 		.mode		= 0555,
525 		.child		= nlm_sysctls,
526 	},
527 	{ }
528 };
529 
530 static struct ctl_table nlm_sysctl_root[] = {
531 	{
532 		.procname	= "fs",
533 		.mode		= 0555,
534 		.child		= nlm_sysctl_dir,
535 	},
536 	{ }
537 };
538 
539 #endif	/* CONFIG_SYSCTL */
540 
541 /*
542  * Module (and sysfs) parameters.
543  */
544 
545 #define param_set_min_max(name, type, which_strtol, min, max)		\
546 static int param_set_##name(const char *val, const struct kernel_param *kp) \
547 {									\
548 	char *endp;							\
549 	__typeof__(type) num = which_strtol(val, &endp, 0);		\
550 	if (endp == val || *endp || num < (min) || num > (max))		\
551 		return -EINVAL;						\
552 	*((type *) kp->arg) = num;					\
553 	return 0;							\
554 }
555 
556 static inline int is_callback(u32 proc)
557 {
558 	return proc == NLMPROC_GRANTED
559 		|| proc == NLMPROC_GRANTED_MSG
560 		|| proc == NLMPROC_TEST_RES
561 		|| proc == NLMPROC_LOCK_RES
562 		|| proc == NLMPROC_CANCEL_RES
563 		|| proc == NLMPROC_UNLOCK_RES
564 		|| proc == NLMPROC_NSM_NOTIFY;
565 }
566 
567 
568 static int lockd_authenticate(struct svc_rqst *rqstp)
569 {
570 	rqstp->rq_client = NULL;
571 	switch (rqstp->rq_authop->flavour) {
572 		case RPC_AUTH_NULL:
573 		case RPC_AUTH_UNIX:
574 			rqstp->rq_auth_stat = rpc_auth_ok;
575 			if (rqstp->rq_proc == 0)
576 				return SVC_OK;
577 			if (is_callback(rqstp->rq_proc)) {
578 				/* Leave it to individual procedures to
579 				 * call nlmsvc_lookup_host(rqstp)
580 				 */
581 				return SVC_OK;
582 			}
583 			return svc_set_client(rqstp);
584 	}
585 	rqstp->rq_auth_stat = rpc_autherr_badcred;
586 	return SVC_DENIED;
587 }
588 
589 
590 param_set_min_max(port, int, simple_strtol, 0, 65535)
591 param_set_min_max(grace_period, unsigned long, simple_strtoul,
592 		  nlm_grace_period_min, nlm_grace_period_max)
593 param_set_min_max(timeout, unsigned long, simple_strtoul,
594 		  nlm_timeout_min, nlm_timeout_max)
595 
596 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
597 MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
598 MODULE_LICENSE("GPL");
599 
600 module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
601 		  &nlm_grace_period, 0644);
602 module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
603 		  &nlm_timeout, 0644);
604 module_param_call(nlm_udpport, param_set_port, param_get_int,
605 		  &nlm_udpport, 0644);
606 module_param_call(nlm_tcpport, param_set_port, param_get_int,
607 		  &nlm_tcpport, 0644);
608 module_param(nsm_use_hostnames, bool, 0644);
609 module_param(nlm_max_connections, uint, 0644);
610 
611 static int lockd_init_net(struct net *net)
612 {
613 	struct lockd_net *ln = net_generic(net, lockd_net_id);
614 
615 	INIT_DELAYED_WORK(&ln->grace_period_end, grace_ender);
616 	INIT_LIST_HEAD(&ln->lockd_manager.list);
617 	ln->lockd_manager.block_opens = false;
618 	INIT_LIST_HEAD(&ln->nsm_handles);
619 	return 0;
620 }
621 
622 static void lockd_exit_net(struct net *net)
623 {
624 	struct lockd_net *ln = net_generic(net, lockd_net_id);
625 
626 	WARN_ONCE(!list_empty(&ln->lockd_manager.list),
627 		  "net %x %s: lockd_manager.list is not empty\n",
628 		  net->ns.inum, __func__);
629 	WARN_ONCE(!list_empty(&ln->nsm_handles),
630 		  "net %x %s: nsm_handles list is not empty\n",
631 		  net->ns.inum, __func__);
632 	WARN_ONCE(delayed_work_pending(&ln->grace_period_end),
633 		  "net %x %s: grace_period_end was not cancelled\n",
634 		  net->ns.inum, __func__);
635 }
636 
637 static struct pernet_operations lockd_net_ops = {
638 	.init = lockd_init_net,
639 	.exit = lockd_exit_net,
640 	.id = &lockd_net_id,
641 	.size = sizeof(struct lockd_net),
642 };
643 
644 
645 /*
646  * Initialising and terminating the module.
647  */
648 
649 static int __init init_nlm(void)
650 {
651 	int err;
652 
653 #ifdef CONFIG_SYSCTL
654 	err = -ENOMEM;
655 	nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
656 	if (nlm_sysctl_table == NULL)
657 		goto err_sysctl;
658 #endif
659 	err = register_pernet_subsys(&lockd_net_ops);
660 	if (err)
661 		goto err_pernet;
662 
663 	err = lockd_create_procfs();
664 	if (err)
665 		goto err_procfs;
666 
667 	return 0;
668 
669 err_procfs:
670 	unregister_pernet_subsys(&lockd_net_ops);
671 err_pernet:
672 #ifdef CONFIG_SYSCTL
673 	unregister_sysctl_table(nlm_sysctl_table);
674 err_sysctl:
675 #endif
676 	return err;
677 }
678 
679 static void __exit exit_nlm(void)
680 {
681 	/* FIXME: delete all NLM clients */
682 	nlm_shutdown_hosts();
683 	lockd_remove_procfs();
684 	unregister_pernet_subsys(&lockd_net_ops);
685 #ifdef CONFIG_SYSCTL
686 	unregister_sysctl_table(nlm_sysctl_table);
687 #endif
688 }
689 
690 module_init(init_nlm);
691 module_exit(exit_nlm);
692 
693 /**
694  * nlmsvc_dispatch - Process an NLM Request
695  * @rqstp: incoming request
696  * @statp: pointer to location of accept_stat field in RPC Reply buffer
697  *
698  * Return values:
699  *  %0: Processing complete; do not send a Reply
700  *  %1: Processing complete; send Reply in rqstp->rq_res
701  */
702 static int nlmsvc_dispatch(struct svc_rqst *rqstp, __be32 *statp)
703 {
704 	const struct svc_procedure *procp = rqstp->rq_procinfo;
705 
706 	svcxdr_init_decode(rqstp);
707 	if (!procp->pc_decode(rqstp, &rqstp->rq_arg_stream))
708 		goto out_decode_err;
709 
710 	*statp = procp->pc_func(rqstp);
711 	if (*statp == rpc_drop_reply)
712 		return 0;
713 	if (*statp != rpc_success)
714 		return 1;
715 
716 	svcxdr_init_encode(rqstp);
717 	if (!procp->pc_encode(rqstp, &rqstp->rq_res_stream))
718 		goto out_encode_err;
719 
720 	return 1;
721 
722 out_decode_err:
723 	*statp = rpc_garbage_args;
724 	return 1;
725 
726 out_encode_err:
727 	*statp = rpc_system_err;
728 	return 1;
729 }
730 
731 /*
732  * Define NLM program and procedures
733  */
734 static unsigned int nlmsvc_version1_count[17];
735 static const struct svc_version	nlmsvc_version1 = {
736 	.vs_vers	= 1,
737 	.vs_nproc	= 17,
738 	.vs_proc	= nlmsvc_procedures,
739 	.vs_count	= nlmsvc_version1_count,
740 	.vs_dispatch	= nlmsvc_dispatch,
741 	.vs_xdrsize	= NLMSVC_XDRSIZE,
742 };
743 static unsigned int nlmsvc_version3_count[24];
744 static const struct svc_version	nlmsvc_version3 = {
745 	.vs_vers	= 3,
746 	.vs_nproc	= 24,
747 	.vs_proc	= nlmsvc_procedures,
748 	.vs_count	= nlmsvc_version3_count,
749 	.vs_dispatch	= nlmsvc_dispatch,
750 	.vs_xdrsize	= NLMSVC_XDRSIZE,
751 };
752 #ifdef CONFIG_LOCKD_V4
753 static unsigned int nlmsvc_version4_count[24];
754 static const struct svc_version	nlmsvc_version4 = {
755 	.vs_vers	= 4,
756 	.vs_nproc	= 24,
757 	.vs_proc	= nlmsvc_procedures4,
758 	.vs_count	= nlmsvc_version4_count,
759 	.vs_dispatch	= nlmsvc_dispatch,
760 	.vs_xdrsize	= NLMSVC_XDRSIZE,
761 };
762 #endif
763 static const struct svc_version *nlmsvc_version[] = {
764 	[1] = &nlmsvc_version1,
765 	[3] = &nlmsvc_version3,
766 #ifdef CONFIG_LOCKD_V4
767 	[4] = &nlmsvc_version4,
768 #endif
769 };
770 
771 static struct svc_stat		nlmsvc_stats;
772 
773 #define NLM_NRVERS	ARRAY_SIZE(nlmsvc_version)
774 static struct svc_program	nlmsvc_program = {
775 	.pg_prog		= NLM_PROGRAM,		/* program number */
776 	.pg_nvers		= NLM_NRVERS,		/* number of entries in nlmsvc_version */
777 	.pg_vers		= nlmsvc_version,	/* version table */
778 	.pg_name		= "lockd",		/* service name */
779 	.pg_class		= "nfsd",		/* share authentication with nfsd */
780 	.pg_stats		= &nlmsvc_stats,	/* stats table */
781 	.pg_authenticate	= &lockd_authenticate,	/* export authentication */
782 	.pg_init_request	= svc_generic_init_request,
783 	.pg_rpcbind_set		= svc_generic_rpcbind_set,
784 };
785