xref: /openbmc/linux/net/sunrpc/clnt.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  *  linux/net/sunrpc/clnt.c
3  *
4  *  This file contains the high-level RPC interface.
5  *  It is modeled as a finite state machine to support both synchronous
6  *  and asynchronous requests.
7  *
8  *  -	RPC header generation and argument serialization.
9  *  -	Credential refresh.
10  *  -	TCP connect handling.
11  *  -	Retry of operation when it is suspected the operation failed because
12  *	of uid squashing on the server, or when the credentials were stale
13  *	and need to be refreshed, or when a packet was damaged in transit.
14  *	This may be have to be moved to the VFS layer.
15  *
16  *  NB: BSD uses a more intelligent approach to guessing when a request
17  *  or reply has been lost by keeping the RTO estimate for each procedure.
18  *  We currently make do with a constant timeout value.
19  *
20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
22  */
23 
24 #include <asm/system.h>
25 
26 #include <linux/module.h>
27 #include <linux/types.h>
28 #include <linux/mm.h>
29 #include <linux/slab.h>
30 #include <linux/utsname.h>
31 
32 #include <linux/sunrpc/clnt.h>
33 #include <linux/workqueue.h>
34 #include <linux/sunrpc/rpc_pipe_fs.h>
35 
36 #include <linux/nfs.h>
37 
38 
39 #define RPC_SLACK_SPACE		(1024)	/* total overkill */
40 
41 #ifdef RPC_DEBUG
42 # define RPCDBG_FACILITY	RPCDBG_CALL
43 #endif
44 
45 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
46 
47 
48 static void	call_start(struct rpc_task *task);
49 static void	call_reserve(struct rpc_task *task);
50 static void	call_reserveresult(struct rpc_task *task);
51 static void	call_allocate(struct rpc_task *task);
52 static void	call_encode(struct rpc_task *task);
53 static void	call_decode(struct rpc_task *task);
54 static void	call_bind(struct rpc_task *task);
55 static void	call_bind_status(struct rpc_task *task);
56 static void	call_transmit(struct rpc_task *task);
57 static void	call_status(struct rpc_task *task);
58 static void	call_refresh(struct rpc_task *task);
59 static void	call_refreshresult(struct rpc_task *task);
60 static void	call_timeout(struct rpc_task *task);
61 static void	call_connect(struct rpc_task *task);
62 static void	call_connect_status(struct rpc_task *task);
63 static u32 *	call_header(struct rpc_task *task);
64 static u32 *	call_verify(struct rpc_task *task);
65 
66 
67 static int
68 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
69 {
70 	static uint32_t clntid;
71 	int error;
72 
73 	if (dir_name == NULL)
74 		return 0;
75 	for (;;) {
76 		snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
77 				"%s/clnt%x", dir_name,
78 				(unsigned int)clntid++);
79 		clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
80 		clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
81 		if (!IS_ERR(clnt->cl_dentry))
82 			return 0;
83 		error = PTR_ERR(clnt->cl_dentry);
84 		if (error != -EEXIST) {
85 			printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
86 					clnt->cl_pathname, error);
87 			return error;
88 		}
89 	}
90 }
91 
92 /*
93  * Create an RPC client
94  * FIXME: This should also take a flags argument (as in task->tk_flags).
95  * It's called (among others) from pmap_create_client, which may in
96  * turn be called by an async task. In this case, rpciod should not be
97  * made to sleep too long.
98  */
99 struct rpc_clnt *
100 rpc_new_client(struct rpc_xprt *xprt, char *servname,
101 		  struct rpc_program *program, u32 vers,
102 		  rpc_authflavor_t flavor)
103 {
104 	struct rpc_version	*version;
105 	struct rpc_clnt		*clnt = NULL;
106 	struct rpc_auth		*auth;
107 	int err;
108 	int len;
109 
110 	dprintk("RPC: creating %s client for %s (xprt %p)\n",
111 		program->name, servname, xprt);
112 
113 	err = -EINVAL;
114 	if (!xprt)
115 		goto out_err;
116 	if (vers >= program->nrvers || !(version = program->version[vers]))
117 		goto out_err;
118 
119 	err = -ENOMEM;
120 	clnt = (struct rpc_clnt *) kmalloc(sizeof(*clnt), GFP_KERNEL);
121 	if (!clnt)
122 		goto out_err;
123 	memset(clnt, 0, sizeof(*clnt));
124 	atomic_set(&clnt->cl_users, 0);
125 	atomic_set(&clnt->cl_count, 1);
126 	clnt->cl_parent = clnt;
127 
128 	clnt->cl_server = clnt->cl_inline_name;
129 	len = strlen(servname) + 1;
130 	if (len > sizeof(clnt->cl_inline_name)) {
131 		char *buf = kmalloc(len, GFP_KERNEL);
132 		if (buf != 0)
133 			clnt->cl_server = buf;
134 		else
135 			len = sizeof(clnt->cl_inline_name);
136 	}
137 	strlcpy(clnt->cl_server, servname, len);
138 
139 	clnt->cl_xprt     = xprt;
140 	clnt->cl_procinfo = version->procs;
141 	clnt->cl_maxproc  = version->nrprocs;
142 	clnt->cl_protname = program->name;
143 	clnt->cl_pmap	  = &clnt->cl_pmap_default;
144 	clnt->cl_port     = xprt->addr.sin_port;
145 	clnt->cl_prog     = program->number;
146 	clnt->cl_vers     = version->number;
147 	clnt->cl_prot     = xprt->prot;
148 	clnt->cl_stats    = program->stats;
149 	rpc_init_wait_queue(&clnt->cl_pmap_default.pm_bindwait, "bindwait");
150 
151 	if (!clnt->cl_port)
152 		clnt->cl_autobind = 1;
153 
154 	clnt->cl_rtt = &clnt->cl_rtt_default;
155 	rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
156 
157 	err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
158 	if (err < 0)
159 		goto out_no_path;
160 
161 	auth = rpcauth_create(flavor, clnt);
162 	if (IS_ERR(auth)) {
163 		printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
164 				flavor);
165 		err = PTR_ERR(auth);
166 		goto out_no_auth;
167 	}
168 
169 	/* save the nodename */
170 	clnt->cl_nodelen = strlen(system_utsname.nodename);
171 	if (clnt->cl_nodelen > UNX_MAXNODENAME)
172 		clnt->cl_nodelen = UNX_MAXNODENAME;
173 	memcpy(clnt->cl_nodename, system_utsname.nodename, clnt->cl_nodelen);
174 	return clnt;
175 
176 out_no_auth:
177 	rpc_rmdir(clnt->cl_pathname);
178 out_no_path:
179 	if (clnt->cl_server != clnt->cl_inline_name)
180 		kfree(clnt->cl_server);
181 	kfree(clnt);
182 out_err:
183 	xprt_destroy(xprt);
184 	return ERR_PTR(err);
185 }
186 
187 /**
188  * Create an RPC client
189  * @xprt - pointer to xprt struct
190  * @servname - name of server
191  * @info - rpc_program
192  * @version - rpc_program version
193  * @authflavor - rpc_auth flavour to use
194  *
195  * Creates an RPC client structure, then pings the server in order to
196  * determine if it is up, and if it supports this program and version.
197  *
198  * This function should never be called by asynchronous tasks such as
199  * the portmapper.
200  */
201 struct rpc_clnt *rpc_create_client(struct rpc_xprt *xprt, char *servname,
202 		struct rpc_program *info, u32 version, rpc_authflavor_t authflavor)
203 {
204 	struct rpc_clnt *clnt;
205 	int err;
206 
207 	clnt = rpc_new_client(xprt, servname, info, version, authflavor);
208 	if (IS_ERR(clnt))
209 		return clnt;
210 	err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
211 	if (err == 0)
212 		return clnt;
213 	rpc_shutdown_client(clnt);
214 	return ERR_PTR(err);
215 }
216 
217 /*
218  * This function clones the RPC client structure. It allows us to share the
219  * same transport while varying parameters such as the authentication
220  * flavour.
221  */
222 struct rpc_clnt *
223 rpc_clone_client(struct rpc_clnt *clnt)
224 {
225 	struct rpc_clnt *new;
226 
227 	new = (struct rpc_clnt *)kmalloc(sizeof(*new), GFP_KERNEL);
228 	if (!new)
229 		goto out_no_clnt;
230 	memcpy(new, clnt, sizeof(*new));
231 	atomic_set(&new->cl_count, 1);
232 	atomic_set(&new->cl_users, 0);
233 	new->cl_parent = clnt;
234 	atomic_inc(&clnt->cl_count);
235 	/* Duplicate portmapper */
236 	rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
237 	/* Turn off autobind on clones */
238 	new->cl_autobind = 0;
239 	new->cl_oneshot = 0;
240 	new->cl_dead = 0;
241 	rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
242 	if (new->cl_auth)
243 		atomic_inc(&new->cl_auth->au_count);
244 	new->cl_pmap		= &new->cl_pmap_default;
245 	rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
246 	return new;
247 out_no_clnt:
248 	printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
249 	return ERR_PTR(-ENOMEM);
250 }
251 
252 /*
253  * Properly shut down an RPC client, terminating all outstanding
254  * requests. Note that we must be certain that cl_oneshot and
255  * cl_dead are cleared, or else the client would be destroyed
256  * when the last task releases it.
257  */
258 int
259 rpc_shutdown_client(struct rpc_clnt *clnt)
260 {
261 	dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
262 			clnt->cl_protname, clnt->cl_server,
263 			atomic_read(&clnt->cl_users));
264 
265 	while (atomic_read(&clnt->cl_users) > 0) {
266 		/* Don't let rpc_release_client destroy us */
267 		clnt->cl_oneshot = 0;
268 		clnt->cl_dead = 0;
269 		rpc_killall_tasks(clnt);
270 		sleep_on_timeout(&destroy_wait, 1*HZ);
271 	}
272 
273 	if (atomic_read(&clnt->cl_users) < 0) {
274 		printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
275 				clnt, atomic_read(&clnt->cl_users));
276 #ifdef RPC_DEBUG
277 		rpc_show_tasks();
278 #endif
279 		BUG();
280 	}
281 
282 	return rpc_destroy_client(clnt);
283 }
284 
285 /*
286  * Delete an RPC client
287  */
288 int
289 rpc_destroy_client(struct rpc_clnt *clnt)
290 {
291 	if (!atomic_dec_and_test(&clnt->cl_count))
292 		return 1;
293 	BUG_ON(atomic_read(&clnt->cl_users) != 0);
294 
295 	dprintk("RPC: destroying %s client for %s\n",
296 			clnt->cl_protname, clnt->cl_server);
297 	if (clnt->cl_auth) {
298 		rpcauth_destroy(clnt->cl_auth);
299 		clnt->cl_auth = NULL;
300 	}
301 	if (clnt->cl_parent != clnt) {
302 		rpc_destroy_client(clnt->cl_parent);
303 		goto out_free;
304 	}
305 	if (clnt->cl_pathname[0])
306 		rpc_rmdir(clnt->cl_pathname);
307 	if (clnt->cl_xprt) {
308 		xprt_destroy(clnt->cl_xprt);
309 		clnt->cl_xprt = NULL;
310 	}
311 	if (clnt->cl_server != clnt->cl_inline_name)
312 		kfree(clnt->cl_server);
313 out_free:
314 	kfree(clnt);
315 	return 0;
316 }
317 
318 /*
319  * Release an RPC client
320  */
321 void
322 rpc_release_client(struct rpc_clnt *clnt)
323 {
324 	dprintk("RPC:      rpc_release_client(%p, %d)\n",
325 				clnt, atomic_read(&clnt->cl_users));
326 
327 	if (!atomic_dec_and_test(&clnt->cl_users))
328 		return;
329 	wake_up(&destroy_wait);
330 	if (clnt->cl_oneshot || clnt->cl_dead)
331 		rpc_destroy_client(clnt);
332 }
333 
334 /**
335  * rpc_bind_new_program - bind a new RPC program to an existing client
336  * @old - old rpc_client
337  * @program - rpc program to set
338  * @vers - rpc program version
339  *
340  * Clones the rpc client and sets up a new RPC program. This is mainly
341  * of use for enabling different RPC programs to share the same transport.
342  * The Sun NFSv2/v3 ACL protocol can do this.
343  */
344 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
345 				      struct rpc_program *program,
346 				      int vers)
347 {
348 	struct rpc_clnt *clnt;
349 	struct rpc_version *version;
350 	int err;
351 
352 	BUG_ON(vers >= program->nrvers || !program->version[vers]);
353 	version = program->version[vers];
354 	clnt = rpc_clone_client(old);
355 	if (IS_ERR(clnt))
356 		goto out;
357 	clnt->cl_procinfo = version->procs;
358 	clnt->cl_maxproc  = version->nrprocs;
359 	clnt->cl_protname = program->name;
360 	clnt->cl_prog     = program->number;
361 	clnt->cl_vers     = version->number;
362 	clnt->cl_stats    = program->stats;
363 	err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
364 	if (err != 0) {
365 		rpc_shutdown_client(clnt);
366 		clnt = ERR_PTR(err);
367 	}
368 out:
369 	return clnt;
370 }
371 
372 /*
373  * Default callback for async RPC calls
374  */
375 static void
376 rpc_default_callback(struct rpc_task *task)
377 {
378 }
379 
380 /*
381  *	Export the signal mask handling for synchronous code that
382  *	sleeps on RPC calls
383  */
384 #define RPC_INTR_SIGNALS (sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGKILL))
385 
386 static void rpc_save_sigmask(sigset_t *oldset, int intr)
387 {
388 	unsigned long	sigallow = 0;
389 	sigset_t sigmask;
390 
391 	/* Block all signals except those listed in sigallow */
392 	if (intr)
393 		sigallow |= RPC_INTR_SIGNALS;
394 	siginitsetinv(&sigmask, sigallow);
395 	sigprocmask(SIG_BLOCK, &sigmask, oldset);
396 }
397 
398 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
399 {
400 	rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
401 }
402 
403 static inline void rpc_restore_sigmask(sigset_t *oldset)
404 {
405 	sigprocmask(SIG_SETMASK, oldset, NULL);
406 }
407 
408 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
409 {
410 	rpc_save_sigmask(oldset, clnt->cl_intr);
411 }
412 
413 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
414 {
415 	rpc_restore_sigmask(oldset);
416 }
417 
418 /*
419  * New rpc_call implementation
420  */
421 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
422 {
423 	struct rpc_task	*task;
424 	sigset_t	oldset;
425 	int		status;
426 
427 	/* If this client is slain all further I/O fails */
428 	if (clnt->cl_dead)
429 		return -EIO;
430 
431 	BUG_ON(flags & RPC_TASK_ASYNC);
432 
433 	status = -ENOMEM;
434 	task = rpc_new_task(clnt, NULL, flags);
435 	if (task == NULL)
436 		goto out;
437 
438 	/* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
439 	rpc_task_sigmask(task, &oldset);
440 
441 	rpc_call_setup(task, msg, 0);
442 
443 	/* Set up the call info struct and execute the task */
444 	if (task->tk_status == 0) {
445 		status = rpc_execute(task);
446 	} else {
447 		status = task->tk_status;
448 		rpc_release_task(task);
449 	}
450 
451 	rpc_restore_sigmask(&oldset);
452 out:
453 	return status;
454 }
455 
456 /*
457  * New rpc_call implementation
458  */
459 int
460 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
461 	       rpc_action callback, void *data)
462 {
463 	struct rpc_task	*task;
464 	sigset_t	oldset;
465 	int		status;
466 
467 	/* If this client is slain all further I/O fails */
468 	if (clnt->cl_dead)
469 		return -EIO;
470 
471 	flags |= RPC_TASK_ASYNC;
472 
473 	/* Create/initialize a new RPC task */
474 	if (!callback)
475 		callback = rpc_default_callback;
476 	status = -ENOMEM;
477 	if (!(task = rpc_new_task(clnt, callback, flags)))
478 		goto out;
479 	task->tk_calldata = data;
480 
481 	/* Mask signals on GSS_AUTH upcalls */
482 	rpc_task_sigmask(task, &oldset);
483 
484 	rpc_call_setup(task, msg, 0);
485 
486 	/* Set up the call info struct and execute the task */
487 	status = task->tk_status;
488 	if (status == 0)
489 		rpc_execute(task);
490 	else
491 		rpc_release_task(task);
492 
493 	rpc_restore_sigmask(&oldset);
494 out:
495 	return status;
496 }
497 
498 
499 void
500 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
501 {
502 	task->tk_msg   = *msg;
503 	task->tk_flags |= flags;
504 	/* Bind the user cred */
505 	if (task->tk_msg.rpc_cred != NULL)
506 		rpcauth_holdcred(task);
507 	else
508 		rpcauth_bindcred(task);
509 
510 	if (task->tk_status == 0)
511 		task->tk_action = call_start;
512 	else
513 		task->tk_action = NULL;
514 }
515 
516 void
517 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
518 {
519 	struct rpc_xprt *xprt = clnt->cl_xprt;
520 	if (xprt->ops->set_buffer_size)
521 		xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
522 }
523 
524 /*
525  * Return size of largest payload RPC client can support, in bytes
526  *
527  * For stream transports, this is one RPC record fragment (see RFC
528  * 1831), as we don't support multi-record requests yet.  For datagram
529  * transports, this is the size of an IP packet minus the IP, UDP, and
530  * RPC header sizes.
531  */
532 size_t rpc_max_payload(struct rpc_clnt *clnt)
533 {
534 	return clnt->cl_xprt->max_payload;
535 }
536 EXPORT_SYMBOL(rpc_max_payload);
537 
538 /*
539  * Restart an (async) RPC call. Usually called from within the
540  * exit handler.
541  */
542 void
543 rpc_restart_call(struct rpc_task *task)
544 {
545 	if (RPC_ASSASSINATED(task))
546 		return;
547 
548 	task->tk_action = call_start;
549 }
550 
551 /*
552  * 0.  Initial state
553  *
554  *     Other FSM states can be visited zero or more times, but
555  *     this state is visited exactly once for each RPC.
556  */
557 static void
558 call_start(struct rpc_task *task)
559 {
560 	struct rpc_clnt	*clnt = task->tk_client;
561 
562 	dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
563 		clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
564 		(RPC_IS_ASYNC(task) ? "async" : "sync"));
565 
566 	/* Increment call count */
567 	task->tk_msg.rpc_proc->p_count++;
568 	clnt->cl_stats->rpccnt++;
569 	task->tk_action = call_reserve;
570 }
571 
572 /*
573  * 1.	Reserve an RPC call slot
574  */
575 static void
576 call_reserve(struct rpc_task *task)
577 {
578 	dprintk("RPC: %4d call_reserve\n", task->tk_pid);
579 
580 	if (!rpcauth_uptodatecred(task)) {
581 		task->tk_action = call_refresh;
582 		return;
583 	}
584 
585 	task->tk_status  = 0;
586 	task->tk_action  = call_reserveresult;
587 	xprt_reserve(task);
588 }
589 
590 /*
591  * 1b.	Grok the result of xprt_reserve()
592  */
593 static void
594 call_reserveresult(struct rpc_task *task)
595 {
596 	int status = task->tk_status;
597 
598 	dprintk("RPC: %4d call_reserveresult (status %d)\n",
599 				task->tk_pid, task->tk_status);
600 
601 	/*
602 	 * After a call to xprt_reserve(), we must have either
603 	 * a request slot or else an error status.
604 	 */
605 	task->tk_status = 0;
606 	if (status >= 0) {
607 		if (task->tk_rqstp) {
608 			task->tk_action = call_allocate;
609 			return;
610 		}
611 
612 		printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
613 				__FUNCTION__, status);
614 		rpc_exit(task, -EIO);
615 		return;
616 	}
617 
618 	/*
619 	 * Even though there was an error, we may have acquired
620 	 * a request slot somehow.  Make sure not to leak it.
621 	 */
622 	if (task->tk_rqstp) {
623 		printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
624 				__FUNCTION__, status);
625 		xprt_release(task);
626 	}
627 
628 	switch (status) {
629 	case -EAGAIN:	/* woken up; retry */
630 		task->tk_action = call_reserve;
631 		return;
632 	case -EIO:	/* probably a shutdown */
633 		break;
634 	default:
635 		printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
636 				__FUNCTION__, status);
637 		break;
638 	}
639 	rpc_exit(task, status);
640 }
641 
642 /*
643  * 2.	Allocate the buffer. For details, see sched.c:rpc_malloc.
644  *	(Note: buffer memory is freed in rpc_task_release).
645  */
646 static void
647 call_allocate(struct rpc_task *task)
648 {
649 	unsigned int	bufsiz;
650 
651 	dprintk("RPC: %4d call_allocate (status %d)\n",
652 				task->tk_pid, task->tk_status);
653 	task->tk_action = call_bind;
654 	if (task->tk_buffer)
655 		return;
656 
657 	/* FIXME: compute buffer requirements more exactly using
658 	 * auth->au_wslack */
659 	bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
660 
661 	if (rpc_malloc(task, bufsiz << 1) != NULL)
662 		return;
663 	printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
664 
665 	if (RPC_IS_ASYNC(task) || !signalled()) {
666 		xprt_release(task);
667 		task->tk_action = call_reserve;
668 		rpc_delay(task, HZ>>4);
669 		return;
670 	}
671 
672 	rpc_exit(task, -ERESTARTSYS);
673 }
674 
675 /*
676  * 3.	Encode arguments of an RPC call
677  */
678 static void
679 call_encode(struct rpc_task *task)
680 {
681 	struct rpc_rqst	*req = task->tk_rqstp;
682 	struct xdr_buf *sndbuf = &req->rq_snd_buf;
683 	struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
684 	unsigned int	bufsiz;
685 	kxdrproc_t	encode;
686 	u32		*p;
687 
688 	dprintk("RPC: %4d call_encode (status %d)\n",
689 				task->tk_pid, task->tk_status);
690 
691 	/* Default buffer setup */
692 	bufsiz = task->tk_bufsize >> 1;
693 	sndbuf->head[0].iov_base = (void *)task->tk_buffer;
694 	sndbuf->head[0].iov_len  = bufsiz;
695 	sndbuf->tail[0].iov_len  = 0;
696 	sndbuf->page_len	 = 0;
697 	sndbuf->len		 = 0;
698 	sndbuf->buflen		 = bufsiz;
699 	rcvbuf->head[0].iov_base = (void *)((char *)task->tk_buffer + bufsiz);
700 	rcvbuf->head[0].iov_len  = bufsiz;
701 	rcvbuf->tail[0].iov_len  = 0;
702 	rcvbuf->page_len	 = 0;
703 	rcvbuf->len		 = 0;
704 	rcvbuf->buflen		 = bufsiz;
705 
706 	/* Encode header and provided arguments */
707 	encode = task->tk_msg.rpc_proc->p_encode;
708 	if (!(p = call_header(task))) {
709 		printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
710 		rpc_exit(task, -EIO);
711 		return;
712 	}
713 	if (encode == NULL)
714 		return;
715 
716 	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
717 			task->tk_msg.rpc_argp);
718 	if (task->tk_status == -ENOMEM) {
719 		/* XXX: Is this sane? */
720 		rpc_delay(task, 3*HZ);
721 		task->tk_status = -EAGAIN;
722 	}
723 }
724 
725 /*
726  * 4.	Get the server port number if not yet set
727  */
728 static void
729 call_bind(struct rpc_task *task)
730 {
731 	struct rpc_clnt	*clnt = task->tk_client;
732 
733 	dprintk("RPC: %4d call_bind (status %d)\n",
734 				task->tk_pid, task->tk_status);
735 
736 	task->tk_action = call_connect;
737 	if (!clnt->cl_port) {
738 		task->tk_action = call_bind_status;
739 		task->tk_timeout = task->tk_xprt->bind_timeout;
740 		rpc_getport(task, clnt);
741 	}
742 }
743 
744 /*
745  * 4a.	Sort out bind result
746  */
747 static void
748 call_bind_status(struct rpc_task *task)
749 {
750 	int status = -EACCES;
751 
752 	if (task->tk_status >= 0) {
753 		dprintk("RPC: %4d call_bind_status (status %d)\n",
754 					task->tk_pid, task->tk_status);
755 		task->tk_status = 0;
756 		task->tk_action = call_connect;
757 		return;
758 	}
759 
760 	switch (task->tk_status) {
761 	case -EACCES:
762 		dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
763 				task->tk_pid);
764 		rpc_delay(task, 3*HZ);
765 		goto retry_bind;
766 	case -ETIMEDOUT:
767 		dprintk("RPC: %4d rpcbind request timed out\n",
768 				task->tk_pid);
769 		if (RPC_IS_SOFT(task)) {
770 			status = -EIO;
771 			break;
772 		}
773 		goto retry_bind;
774 	case -EPFNOSUPPORT:
775 		dprintk("RPC: %4d remote rpcbind service unavailable\n",
776 				task->tk_pid);
777 		break;
778 	case -EPROTONOSUPPORT:
779 		dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
780 				task->tk_pid);
781 		break;
782 	default:
783 		dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
784 				task->tk_pid, -task->tk_status);
785 		status = -EIO;
786 		break;
787 	}
788 
789 	rpc_exit(task, status);
790 	return;
791 
792 retry_bind:
793 	task->tk_status = 0;
794 	task->tk_action = call_bind;
795 	return;
796 }
797 
798 /*
799  * 4b.	Connect to the RPC server
800  */
801 static void
802 call_connect(struct rpc_task *task)
803 {
804 	struct rpc_xprt *xprt = task->tk_xprt;
805 
806 	dprintk("RPC: %4d call_connect xprt %p %s connected\n",
807 			task->tk_pid, xprt,
808 			(xprt_connected(xprt) ? "is" : "is not"));
809 
810 	task->tk_action = call_transmit;
811 	if (!xprt_connected(xprt)) {
812 		task->tk_action = call_connect_status;
813 		if (task->tk_status < 0)
814 			return;
815 		xprt_connect(task);
816 	}
817 }
818 
819 /*
820  * 4c.	Sort out connect result
821  */
822 static void
823 call_connect_status(struct rpc_task *task)
824 {
825 	struct rpc_clnt *clnt = task->tk_client;
826 	int status = task->tk_status;
827 
828 	dprintk("RPC: %5u call_connect_status (status %d)\n",
829 				task->tk_pid, task->tk_status);
830 
831 	task->tk_status = 0;
832 	if (status >= 0) {
833 		clnt->cl_stats->netreconn++;
834 		task->tk_action = call_transmit;
835 		return;
836 	}
837 
838 	/* Something failed: remote service port may have changed */
839 	if (clnt->cl_autobind)
840 		clnt->cl_port = 0;
841 
842 	switch (status) {
843 	case -ENOTCONN:
844 	case -ETIMEDOUT:
845 	case -EAGAIN:
846 		task->tk_action = call_bind;
847 		break;
848 	default:
849 		rpc_exit(task, -EIO);
850 		break;
851 	}
852 }
853 
854 /*
855  * 5.	Transmit the RPC request, and wait for reply
856  */
857 static void
858 call_transmit(struct rpc_task *task)
859 {
860 	dprintk("RPC: %4d call_transmit (status %d)\n",
861 				task->tk_pid, task->tk_status);
862 
863 	task->tk_action = call_status;
864 	if (task->tk_status < 0)
865 		return;
866 	task->tk_status = xprt_prepare_transmit(task);
867 	if (task->tk_status != 0)
868 		return;
869 	/* Encode here so that rpcsec_gss can use correct sequence number. */
870 	if (task->tk_rqstp->rq_bytes_sent == 0) {
871 		call_encode(task);
872 		/* Did the encode result in an error condition? */
873 		if (task->tk_status != 0)
874 			goto out_nosend;
875 	}
876 	xprt_transmit(task);
877 	if (task->tk_status < 0)
878 		return;
879 	if (!task->tk_msg.rpc_proc->p_decode) {
880 		task->tk_action = NULL;
881 		rpc_wake_up_task(task);
882 	}
883 	return;
884 out_nosend:
885 	/* release socket write lock before attempting to handle error */
886 	xprt_abort_transmit(task);
887 }
888 
889 /*
890  * 6.	Sort out the RPC call status
891  */
892 static void
893 call_status(struct rpc_task *task)
894 {
895 	struct rpc_clnt	*clnt = task->tk_client;
896 	struct rpc_rqst	*req = task->tk_rqstp;
897 	int		status;
898 
899 	if (req->rq_received > 0 && !req->rq_bytes_sent)
900 		task->tk_status = req->rq_received;
901 
902 	dprintk("RPC: %4d call_status (status %d)\n",
903 				task->tk_pid, task->tk_status);
904 
905 	status = task->tk_status;
906 	if (status >= 0) {
907 		task->tk_action = call_decode;
908 		return;
909 	}
910 
911 	task->tk_status = 0;
912 	switch(status) {
913 	case -ETIMEDOUT:
914 		task->tk_action = call_timeout;
915 		break;
916 	case -ECONNREFUSED:
917 	case -ENOTCONN:
918 		req->rq_bytes_sent = 0;
919 		if (clnt->cl_autobind)
920 			clnt->cl_port = 0;
921 		task->tk_action = call_bind;
922 		break;
923 	case -EAGAIN:
924 		task->tk_action = call_transmit;
925 		break;
926 	case -EIO:
927 		/* shutdown or soft timeout */
928 		rpc_exit(task, status);
929 		break;
930 	default:
931 		if (clnt->cl_chatty)
932 			printk("%s: RPC call returned error %d\n",
933 			       clnt->cl_protname, -status);
934 		rpc_exit(task, status);
935 		break;
936 	}
937 }
938 
939 /*
940  * 6a.	Handle RPC timeout
941  * 	We do not release the request slot, so we keep using the
942  *	same XID for all retransmits.
943  */
944 static void
945 call_timeout(struct rpc_task *task)
946 {
947 	struct rpc_clnt	*clnt = task->tk_client;
948 
949 	if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
950 		dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
951 		goto retry;
952 	}
953 
954 	dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
955 	if (RPC_IS_SOFT(task)) {
956 		if (clnt->cl_chatty)
957 			printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
958 				clnt->cl_protname, clnt->cl_server);
959 		rpc_exit(task, -EIO);
960 		return;
961 	}
962 
963 	if (clnt->cl_chatty && !(task->tk_flags & RPC_CALL_MAJORSEEN)) {
964 		task->tk_flags |= RPC_CALL_MAJORSEEN;
965 		printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
966 			clnt->cl_protname, clnt->cl_server);
967 	}
968 	if (clnt->cl_autobind)
969 		clnt->cl_port = 0;
970 
971 retry:
972 	clnt->cl_stats->rpcretrans++;
973 	task->tk_action = call_bind;
974 	task->tk_status = 0;
975 }
976 
977 /*
978  * 7.	Decode the RPC reply
979  */
980 static void
981 call_decode(struct rpc_task *task)
982 {
983 	struct rpc_clnt	*clnt = task->tk_client;
984 	struct rpc_rqst	*req = task->tk_rqstp;
985 	kxdrproc_t	decode = task->tk_msg.rpc_proc->p_decode;
986 	u32		*p;
987 
988 	dprintk("RPC: %4d call_decode (status %d)\n",
989 				task->tk_pid, task->tk_status);
990 
991 	if (clnt->cl_chatty && (task->tk_flags & RPC_CALL_MAJORSEEN)) {
992 		printk(KERN_NOTICE "%s: server %s OK\n",
993 			clnt->cl_protname, clnt->cl_server);
994 		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
995 	}
996 
997 	if (task->tk_status < 12) {
998 		if (!RPC_IS_SOFT(task)) {
999 			task->tk_action = call_bind;
1000 			clnt->cl_stats->rpcretrans++;
1001 			goto out_retry;
1002 		}
1003 		printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1004 			clnt->cl_protname, task->tk_status);
1005 		rpc_exit(task, -EIO);
1006 		return;
1007 	}
1008 
1009 	req->rq_rcv_buf.len = req->rq_private_buf.len;
1010 
1011 	/* Check that the softirq receive buffer is valid */
1012 	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1013 				sizeof(req->rq_rcv_buf)) != 0);
1014 
1015 	/* Verify the RPC header */
1016 	if (!(p = call_verify(task))) {
1017 		if (task->tk_action == NULL)
1018 			return;
1019 		goto out_retry;
1020 	}
1021 
1022 	task->tk_action = NULL;
1023 
1024 	if (decode)
1025 		task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1026 						      task->tk_msg.rpc_resp);
1027 	dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1028 					task->tk_status);
1029 	return;
1030 out_retry:
1031 	req->rq_received = req->rq_private_buf.len = 0;
1032 	task->tk_status = 0;
1033 }
1034 
1035 /*
1036  * 8.	Refresh the credentials if rejected by the server
1037  */
1038 static void
1039 call_refresh(struct rpc_task *task)
1040 {
1041 	dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1042 
1043 	xprt_release(task);	/* Must do to obtain new XID */
1044 	task->tk_action = call_refreshresult;
1045 	task->tk_status = 0;
1046 	task->tk_client->cl_stats->rpcauthrefresh++;
1047 	rpcauth_refreshcred(task);
1048 }
1049 
1050 /*
1051  * 8a.	Process the results of a credential refresh
1052  */
1053 static void
1054 call_refreshresult(struct rpc_task *task)
1055 {
1056 	int status = task->tk_status;
1057 	dprintk("RPC: %4d call_refreshresult (status %d)\n",
1058 				task->tk_pid, task->tk_status);
1059 
1060 	task->tk_status = 0;
1061 	task->tk_action = call_reserve;
1062 	if (status >= 0 && rpcauth_uptodatecred(task))
1063 		return;
1064 	if (status == -EACCES) {
1065 		rpc_exit(task, -EACCES);
1066 		return;
1067 	}
1068 	task->tk_action = call_refresh;
1069 	if (status != -ETIMEDOUT)
1070 		rpc_delay(task, 3*HZ);
1071 	return;
1072 }
1073 
1074 /*
1075  * Call header serialization
1076  */
1077 static u32 *
1078 call_header(struct rpc_task *task)
1079 {
1080 	struct rpc_clnt *clnt = task->tk_client;
1081 	struct rpc_rqst	*req = task->tk_rqstp;
1082 	u32		*p = req->rq_svec[0].iov_base;
1083 
1084 	/* FIXME: check buffer size? */
1085 
1086 	p = xprt_skip_transport_header(task->tk_xprt, p);
1087 	*p++ = req->rq_xid;		/* XID */
1088 	*p++ = htonl(RPC_CALL);		/* CALL */
1089 	*p++ = htonl(RPC_VERSION);	/* RPC version */
1090 	*p++ = htonl(clnt->cl_prog);	/* program number */
1091 	*p++ = htonl(clnt->cl_vers);	/* program version */
1092 	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
1093 	p = rpcauth_marshcred(task, p);
1094 	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1095 	return p;
1096 }
1097 
1098 /*
1099  * Reply header verification
1100  */
1101 static u32 *
1102 call_verify(struct rpc_task *task)
1103 {
1104 	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1105 	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1106 	u32	*p = iov->iov_base, n;
1107 	int error = -EACCES;
1108 
1109 	if ((len -= 3) < 0)
1110 		goto out_overflow;
1111 	p += 1;	/* skip XID */
1112 
1113 	if ((n = ntohl(*p++)) != RPC_REPLY) {
1114 		printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1115 		goto out_retry;
1116 	}
1117 	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1118 		if (--len < 0)
1119 			goto out_overflow;
1120 		switch ((n = ntohl(*p++))) {
1121 			case RPC_AUTH_ERROR:
1122 				break;
1123 			case RPC_MISMATCH:
1124 				dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1125 				error = -EPROTONOSUPPORT;
1126 				goto out_err;
1127 			default:
1128 				dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1129 				goto out_eio;
1130 		}
1131 		if (--len < 0)
1132 			goto out_overflow;
1133 		switch ((n = ntohl(*p++))) {
1134 		case RPC_AUTH_REJECTEDCRED:
1135 		case RPC_AUTH_REJECTEDVERF:
1136 		case RPCSEC_GSS_CREDPROBLEM:
1137 		case RPCSEC_GSS_CTXPROBLEM:
1138 			if (!task->tk_cred_retry)
1139 				break;
1140 			task->tk_cred_retry--;
1141 			dprintk("RPC: %4d call_verify: retry stale creds\n",
1142 							task->tk_pid);
1143 			rpcauth_invalcred(task);
1144 			task->tk_action = call_refresh;
1145 			return NULL;
1146 		case RPC_AUTH_BADCRED:
1147 		case RPC_AUTH_BADVERF:
1148 			/* possibly garbled cred/verf? */
1149 			if (!task->tk_garb_retry)
1150 				break;
1151 			task->tk_garb_retry--;
1152 			dprintk("RPC: %4d call_verify: retry garbled creds\n",
1153 							task->tk_pid);
1154 			task->tk_action = call_bind;
1155 			return NULL;
1156 		case RPC_AUTH_TOOWEAK:
1157 			printk(KERN_NOTICE "call_verify: server requires stronger "
1158 			       "authentication.\n");
1159 			break;
1160 		default:
1161 			printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1162 			error = -EIO;
1163 		}
1164 		dprintk("RPC: %4d call_verify: call rejected %d\n",
1165 						task->tk_pid, n);
1166 		goto out_err;
1167 	}
1168 	if (!(p = rpcauth_checkverf(task, p))) {
1169 		printk(KERN_WARNING "call_verify: auth check failed\n");
1170 		goto out_retry;		/* bad verifier, retry */
1171 	}
1172 	len = p - (u32 *)iov->iov_base - 1;
1173 	if (len < 0)
1174 		goto out_overflow;
1175 	switch ((n = ntohl(*p++))) {
1176 	case RPC_SUCCESS:
1177 		return p;
1178 	case RPC_PROG_UNAVAIL:
1179 		dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1180 				(unsigned int)task->tk_client->cl_prog,
1181 				task->tk_client->cl_server);
1182 		error = -EPFNOSUPPORT;
1183 		goto out_err;
1184 	case RPC_PROG_MISMATCH:
1185 		dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1186 				(unsigned int)task->tk_client->cl_prog,
1187 				(unsigned int)task->tk_client->cl_vers,
1188 				task->tk_client->cl_server);
1189 		error = -EPROTONOSUPPORT;
1190 		goto out_err;
1191 	case RPC_PROC_UNAVAIL:
1192 		dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1193 				task->tk_msg.rpc_proc,
1194 				task->tk_client->cl_prog,
1195 				task->tk_client->cl_vers,
1196 				task->tk_client->cl_server);
1197 		error = -EOPNOTSUPP;
1198 		goto out_err;
1199 	case RPC_GARBAGE_ARGS:
1200 		dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1201 		break;			/* retry */
1202 	default:
1203 		printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1204 		/* Also retry */
1205 	}
1206 
1207 out_retry:
1208 	task->tk_client->cl_stats->rpcgarbage++;
1209 	if (task->tk_garb_retry) {
1210 		task->tk_garb_retry--;
1211 		dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1212 		task->tk_action = call_bind;
1213 		return NULL;
1214 	}
1215 	printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1216 out_eio:
1217 	error = -EIO;
1218 out_err:
1219 	rpc_exit(task, error);
1220 	return NULL;
1221 out_overflow:
1222 	printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1223 	goto out_retry;
1224 }
1225 
1226 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1227 {
1228 	return 0;
1229 }
1230 
1231 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1232 {
1233 	return 0;
1234 }
1235 
1236 static struct rpc_procinfo rpcproc_null = {
1237 	.p_encode = rpcproc_encode_null,
1238 	.p_decode = rpcproc_decode_null,
1239 };
1240 
1241 int rpc_ping(struct rpc_clnt *clnt, int flags)
1242 {
1243 	struct rpc_message msg = {
1244 		.rpc_proc = &rpcproc_null,
1245 	};
1246 	int err;
1247 	msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1248 	err = rpc_call_sync(clnt, &msg, flags);
1249 	put_rpccred(msg.rpc_cred);
1250 	return err;
1251 }
1252