xref: /openbmc/linux/net/sunrpc/rpcb_clnt.c (revision 81d67439)
1 /*
2  * In-kernel rpcbind client supporting versions 2, 3, and 4 of the rpcbind
3  * protocol
4  *
5  * Based on RFC 1833: "Binding Protocols for ONC RPC Version 2" and
6  * RFC 3530: "Network File System (NFS) version 4 Protocol"
7  *
8  * Original: Gilles Quillard, Bull Open Source, 2005 <gilles.quillard@bull.net>
9  * Updated: Chuck Lever, Oracle Corporation, 2007 <chuck.lever@oracle.com>
10  *
11  * Descended from net/sunrpc/pmap_clnt.c,
12  *  Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
13  */
14 
15 #include <linux/module.h>
16 
17 #include <linux/types.h>
18 #include <linux/socket.h>
19 #include <linux/un.h>
20 #include <linux/in.h>
21 #include <linux/in6.h>
22 #include <linux/kernel.h>
23 #include <linux/errno.h>
24 #include <linux/mutex.h>
25 #include <linux/slab.h>
26 #include <net/ipv6.h>
27 
28 #include <linux/sunrpc/clnt.h>
29 #include <linux/sunrpc/sched.h>
30 #include <linux/sunrpc/xprtsock.h>
31 
32 #ifdef RPC_DEBUG
33 # define RPCDBG_FACILITY	RPCDBG_BIND
34 #endif
35 
36 #define RPCBIND_SOCK_PATHNAME	"/var/run/rpcbind.sock"
37 
38 #define RPCBIND_PROGRAM		(100000u)
39 #define RPCBIND_PORT		(111u)
40 
41 #define RPCBVERS_2		(2u)
42 #define RPCBVERS_3		(3u)
43 #define RPCBVERS_4		(4u)
44 
45 enum {
46 	RPCBPROC_NULL,
47 	RPCBPROC_SET,
48 	RPCBPROC_UNSET,
49 	RPCBPROC_GETPORT,
50 	RPCBPROC_GETADDR = 3,		/* alias for GETPORT */
51 	RPCBPROC_DUMP,
52 	RPCBPROC_CALLIT,
53 	RPCBPROC_BCAST = 5,		/* alias for CALLIT */
54 	RPCBPROC_GETTIME,
55 	RPCBPROC_UADDR2TADDR,
56 	RPCBPROC_TADDR2UADDR,
57 	RPCBPROC_GETVERSADDR,
58 	RPCBPROC_INDIRECT,
59 	RPCBPROC_GETADDRLIST,
60 	RPCBPROC_GETSTAT,
61 };
62 
63 /*
64  * r_owner
65  *
66  * The "owner" is allowed to unset a service in the rpcbind database.
67  *
68  * For AF_LOCAL SET/UNSET requests, rpcbind treats this string as a
69  * UID which it maps to a local user name via a password lookup.
70  * In all other cases it is ignored.
71  *
72  * For SET/UNSET requests, user space provides a value, even for
73  * network requests, and GETADDR uses an empty string.  We follow
74  * those precedents here.
75  */
76 #define RPCB_OWNER_STRING	"0"
77 #define RPCB_MAXOWNERLEN	sizeof(RPCB_OWNER_STRING)
78 
79 /*
80  * XDR data type sizes
81  */
82 #define RPCB_program_sz		(1)
83 #define RPCB_version_sz		(1)
84 #define RPCB_protocol_sz	(1)
85 #define RPCB_port_sz		(1)
86 #define RPCB_boolean_sz		(1)
87 
88 #define RPCB_netid_sz		(1 + XDR_QUADLEN(RPCBIND_MAXNETIDLEN))
89 #define RPCB_addr_sz		(1 + XDR_QUADLEN(RPCBIND_MAXUADDRLEN))
90 #define RPCB_ownerstring_sz	(1 + XDR_QUADLEN(RPCB_MAXOWNERLEN))
91 
92 /*
93  * XDR argument and result sizes
94  */
95 #define RPCB_mappingargs_sz	(RPCB_program_sz + RPCB_version_sz + \
96 				RPCB_protocol_sz + RPCB_port_sz)
97 #define RPCB_getaddrargs_sz	(RPCB_program_sz + RPCB_version_sz + \
98 				RPCB_netid_sz + RPCB_addr_sz + \
99 				RPCB_ownerstring_sz)
100 
101 #define RPCB_getportres_sz	RPCB_port_sz
102 #define RPCB_setres_sz		RPCB_boolean_sz
103 
104 /*
105  * Note that RFC 1833 does not put any size restrictions on the
106  * address string returned by the remote rpcbind database.
107  */
108 #define RPCB_getaddrres_sz	RPCB_addr_sz
109 
110 static void			rpcb_getport_done(struct rpc_task *, void *);
111 static void			rpcb_map_release(void *data);
112 static struct rpc_program	rpcb_program;
113 
114 static struct rpc_clnt *	rpcb_local_clnt;
115 static struct rpc_clnt *	rpcb_local_clnt4;
116 
117 struct rpcbind_args {
118 	struct rpc_xprt *	r_xprt;
119 
120 	u32			r_prog;
121 	u32			r_vers;
122 	u32			r_prot;
123 	unsigned short		r_port;
124 	const char *		r_netid;
125 	const char *		r_addr;
126 	const char *		r_owner;
127 
128 	int			r_status;
129 };
130 
131 static struct rpc_procinfo rpcb_procedures2[];
132 static struct rpc_procinfo rpcb_procedures3[];
133 static struct rpc_procinfo rpcb_procedures4[];
134 
135 struct rpcb_info {
136 	u32			rpc_vers;
137 	struct rpc_procinfo *	rpc_proc;
138 };
139 
140 static struct rpcb_info rpcb_next_version[];
141 static struct rpcb_info rpcb_next_version6[];
142 
143 static const struct rpc_call_ops rpcb_getport_ops = {
144 	.rpc_call_done		= rpcb_getport_done,
145 	.rpc_release		= rpcb_map_release,
146 };
147 
148 static void rpcb_wake_rpcbind_waiters(struct rpc_xprt *xprt, int status)
149 {
150 	xprt_clear_binding(xprt);
151 	rpc_wake_up_status(&xprt->binding, status);
152 }
153 
154 static void rpcb_map_release(void *data)
155 {
156 	struct rpcbind_args *map = data;
157 
158 	rpcb_wake_rpcbind_waiters(map->r_xprt, map->r_status);
159 	xprt_put(map->r_xprt);
160 	kfree(map->r_addr);
161 	kfree(map);
162 }
163 
164 /*
165  * Returns zero on success, otherwise a negative errno value
166  * is returned.
167  */
168 static int rpcb_create_local_unix(void)
169 {
170 	static const struct sockaddr_un rpcb_localaddr_rpcbind = {
171 		.sun_family		= AF_LOCAL,
172 		.sun_path		= RPCBIND_SOCK_PATHNAME,
173 	};
174 	struct rpc_create_args args = {
175 		.net		= &init_net,
176 		.protocol	= XPRT_TRANSPORT_LOCAL,
177 		.address	= (struct sockaddr *)&rpcb_localaddr_rpcbind,
178 		.addrsize	= sizeof(rpcb_localaddr_rpcbind),
179 		.servername	= "localhost",
180 		.program	= &rpcb_program,
181 		.version	= RPCBVERS_2,
182 		.authflavor	= RPC_AUTH_NULL,
183 	};
184 	struct rpc_clnt *clnt, *clnt4;
185 	int result = 0;
186 
187 	/*
188 	 * Because we requested an RPC PING at transport creation time,
189 	 * this works only if the user space portmapper is rpcbind, and
190 	 * it's listening on AF_LOCAL on the named socket.
191 	 */
192 	clnt = rpc_create(&args);
193 	if (IS_ERR(clnt)) {
194 		dprintk("RPC:       failed to create AF_LOCAL rpcbind "
195 				"client (errno %ld).\n", PTR_ERR(clnt));
196 		result = -PTR_ERR(clnt);
197 		goto out;
198 	}
199 
200 	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
201 	if (IS_ERR(clnt4)) {
202 		dprintk("RPC:       failed to bind second program to "
203 				"rpcbind v4 client (errno %ld).\n",
204 				PTR_ERR(clnt4));
205 		clnt4 = NULL;
206 	}
207 
208 	/* Protected by rpcb_create_local_mutex */
209 	rpcb_local_clnt = clnt;
210 	rpcb_local_clnt4 = clnt4;
211 
212 out:
213 	return result;
214 }
215 
216 /*
217  * Returns zero on success, otherwise a negative errno value
218  * is returned.
219  */
220 static int rpcb_create_local_net(void)
221 {
222 	static const struct sockaddr_in rpcb_inaddr_loopback = {
223 		.sin_family		= AF_INET,
224 		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
225 		.sin_port		= htons(RPCBIND_PORT),
226 	};
227 	struct rpc_create_args args = {
228 		.net		= &init_net,
229 		.protocol	= XPRT_TRANSPORT_TCP,
230 		.address	= (struct sockaddr *)&rpcb_inaddr_loopback,
231 		.addrsize	= sizeof(rpcb_inaddr_loopback),
232 		.servername	= "localhost",
233 		.program	= &rpcb_program,
234 		.version	= RPCBVERS_2,
235 		.authflavor	= RPC_AUTH_UNIX,
236 		.flags		= RPC_CLNT_CREATE_NOPING,
237 	};
238 	struct rpc_clnt *clnt, *clnt4;
239 	int result = 0;
240 
241 	clnt = rpc_create(&args);
242 	if (IS_ERR(clnt)) {
243 		dprintk("RPC:       failed to create local rpcbind "
244 				"client (errno %ld).\n", PTR_ERR(clnt));
245 		result = -PTR_ERR(clnt);
246 		goto out;
247 	}
248 
249 	/*
250 	 * This results in an RPC ping.  On systems running portmapper,
251 	 * the v4 ping will fail.  Proceed anyway, but disallow rpcb
252 	 * v4 upcalls.
253 	 */
254 	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
255 	if (IS_ERR(clnt4)) {
256 		dprintk("RPC:       failed to bind second program to "
257 				"rpcbind v4 client (errno %ld).\n",
258 				PTR_ERR(clnt4));
259 		clnt4 = NULL;
260 	}
261 
262 	/* Protected by rpcb_create_local_mutex */
263 	rpcb_local_clnt = clnt;
264 	rpcb_local_clnt4 = clnt4;
265 
266 out:
267 	return result;
268 }
269 
270 /*
271  * Returns zero on success, otherwise a negative errno value
272  * is returned.
273  */
274 static int rpcb_create_local(void)
275 {
276 	static DEFINE_MUTEX(rpcb_create_local_mutex);
277 	int result = 0;
278 
279 	if (rpcb_local_clnt)
280 		return result;
281 
282 	mutex_lock(&rpcb_create_local_mutex);
283 	if (rpcb_local_clnt)
284 		goto out;
285 
286 	if (rpcb_create_local_unix() != 0)
287 		result = rpcb_create_local_net();
288 
289 out:
290 	mutex_unlock(&rpcb_create_local_mutex);
291 	return result;
292 }
293 
294 static struct rpc_clnt *rpcb_create(char *hostname, struct sockaddr *srvaddr,
295 				    size_t salen, int proto, u32 version)
296 {
297 	struct rpc_create_args args = {
298 		.net		= &init_net,
299 		.protocol	= proto,
300 		.address	= srvaddr,
301 		.addrsize	= salen,
302 		.servername	= hostname,
303 		.program	= &rpcb_program,
304 		.version	= version,
305 		.authflavor	= RPC_AUTH_UNIX,
306 		.flags		= (RPC_CLNT_CREATE_NOPING |
307 					RPC_CLNT_CREATE_NONPRIVPORT),
308 	};
309 
310 	switch (srvaddr->sa_family) {
311 	case AF_INET:
312 		((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
313 		break;
314 	case AF_INET6:
315 		((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
316 		break;
317 	default:
318 		return ERR_PTR(-EAFNOSUPPORT);
319 	}
320 
321 	return rpc_create(&args);
322 }
323 
324 static int rpcb_register_call(struct rpc_clnt *clnt, struct rpc_message *msg)
325 {
326 	int result, error = 0;
327 
328 	msg->rpc_resp = &result;
329 
330 	error = rpc_call_sync(clnt, msg, RPC_TASK_SOFTCONN);
331 	if (error < 0) {
332 		dprintk("RPC:       failed to contact local rpcbind "
333 				"server (errno %d).\n", -error);
334 		return error;
335 	}
336 
337 	if (!result)
338 		return -EACCES;
339 	return 0;
340 }
341 
342 /**
343  * rpcb_register - set or unset a port registration with the local rpcbind svc
344  * @prog: RPC program number to bind
345  * @vers: RPC version number to bind
346  * @prot: transport protocol to register
347  * @port: port value to register
348  *
349  * Returns zero if the registration request was dispatched successfully
350  * and the rpcbind daemon returned success.  Otherwise, returns an errno
351  * value that reflects the nature of the error (request could not be
352  * dispatched, timed out, or rpcbind returned an error).
353  *
354  * RPC services invoke this function to advertise their contact
355  * information via the system's rpcbind daemon.  RPC services
356  * invoke this function once for each [program, version, transport]
357  * tuple they wish to advertise.
358  *
359  * Callers may also unregister RPC services that are no longer
360  * available by setting the passed-in port to zero.  This removes
361  * all registered transports for [program, version] from the local
362  * rpcbind database.
363  *
364  * This function uses rpcbind protocol version 2 to contact the
365  * local rpcbind daemon.
366  *
367  * Registration works over both AF_INET and AF_INET6, and services
368  * registered via this function are advertised as available for any
369  * address.  If the local rpcbind daemon is listening on AF_INET6,
370  * services registered via this function will be advertised on
371  * IN6ADDR_ANY (ie available for all AF_INET and AF_INET6
372  * addresses).
373  */
374 int rpcb_register(u32 prog, u32 vers, int prot, unsigned short port)
375 {
376 	struct rpcbind_args map = {
377 		.r_prog		= prog,
378 		.r_vers		= vers,
379 		.r_prot		= prot,
380 		.r_port		= port,
381 	};
382 	struct rpc_message msg = {
383 		.rpc_argp	= &map,
384 	};
385 	int error;
386 
387 	error = rpcb_create_local();
388 	if (error)
389 		return error;
390 
391 	dprintk("RPC:       %sregistering (%u, %u, %d, %u) with local "
392 			"rpcbind\n", (port ? "" : "un"),
393 			prog, vers, prot, port);
394 
395 	msg.rpc_proc = &rpcb_procedures2[RPCBPROC_UNSET];
396 	if (port)
397 		msg.rpc_proc = &rpcb_procedures2[RPCBPROC_SET];
398 
399 	return rpcb_register_call(rpcb_local_clnt, &msg);
400 }
401 
402 /*
403  * Fill in AF_INET family-specific arguments to register
404  */
405 static int rpcb_register_inet4(const struct sockaddr *sap,
406 			       struct rpc_message *msg)
407 {
408 	const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
409 	struct rpcbind_args *map = msg->rpc_argp;
410 	unsigned short port = ntohs(sin->sin_port);
411 	int result;
412 
413 	map->r_addr = rpc_sockaddr2uaddr(sap);
414 
415 	dprintk("RPC:       %sregistering [%u, %u, %s, '%s'] with "
416 		"local rpcbind\n", (port ? "" : "un"),
417 			map->r_prog, map->r_vers,
418 			map->r_addr, map->r_netid);
419 
420 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
421 	if (port)
422 		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
423 
424 	result = rpcb_register_call(rpcb_local_clnt4, msg);
425 	kfree(map->r_addr);
426 	return result;
427 }
428 
429 /*
430  * Fill in AF_INET6 family-specific arguments to register
431  */
432 static int rpcb_register_inet6(const struct sockaddr *sap,
433 			       struct rpc_message *msg)
434 {
435 	const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)sap;
436 	struct rpcbind_args *map = msg->rpc_argp;
437 	unsigned short port = ntohs(sin6->sin6_port);
438 	int result;
439 
440 	map->r_addr = rpc_sockaddr2uaddr(sap);
441 
442 	dprintk("RPC:       %sregistering [%u, %u, %s, '%s'] with "
443 		"local rpcbind\n", (port ? "" : "un"),
444 			map->r_prog, map->r_vers,
445 			map->r_addr, map->r_netid);
446 
447 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
448 	if (port)
449 		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
450 
451 	result = rpcb_register_call(rpcb_local_clnt4, msg);
452 	kfree(map->r_addr);
453 	return result;
454 }
455 
456 static int rpcb_unregister_all_protofamilies(struct rpc_message *msg)
457 {
458 	struct rpcbind_args *map = msg->rpc_argp;
459 
460 	dprintk("RPC:       unregistering [%u, %u, '%s'] with "
461 		"local rpcbind\n",
462 			map->r_prog, map->r_vers, map->r_netid);
463 
464 	map->r_addr = "";
465 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
466 
467 	return rpcb_register_call(rpcb_local_clnt4, msg);
468 }
469 
470 /**
471  * rpcb_v4_register - set or unset a port registration with the local rpcbind
472  * @program: RPC program number of service to (un)register
473  * @version: RPC version number of service to (un)register
474  * @address: address family, IP address, and port to (un)register
475  * @netid: netid of transport protocol to (un)register
476  *
477  * Returns zero if the registration request was dispatched successfully
478  * and the rpcbind daemon returned success.  Otherwise, returns an errno
479  * value that reflects the nature of the error (request could not be
480  * dispatched, timed out, or rpcbind returned an error).
481  *
482  * RPC services invoke this function to advertise their contact
483  * information via the system's rpcbind daemon.  RPC services
484  * invoke this function once for each [program, version, address,
485  * netid] tuple they wish to advertise.
486  *
487  * Callers may also unregister RPC services that are registered at a
488  * specific address by setting the port number in @address to zero.
489  * They may unregister all registered protocol families at once for
490  * a service by passing a NULL @address argument.  If @netid is ""
491  * then all netids for [program, version, address] are unregistered.
492  *
493  * This function uses rpcbind protocol version 4 to contact the
494  * local rpcbind daemon.  The local rpcbind daemon must support
495  * version 4 of the rpcbind protocol in order for these functions
496  * to register a service successfully.
497  *
498  * Supported netids include "udp" and "tcp" for UDP and TCP over
499  * IPv4, and "udp6" and "tcp6" for UDP and TCP over IPv6,
500  * respectively.
501  *
502  * The contents of @address determine the address family and the
503  * port to be registered.  The usual practice is to pass INADDR_ANY
504  * as the raw address, but specifying a non-zero address is also
505  * supported by this API if the caller wishes to advertise an RPC
506  * service on a specific network interface.
507  *
508  * Note that passing in INADDR_ANY does not create the same service
509  * registration as IN6ADDR_ANY.  The former advertises an RPC
510  * service on any IPv4 address, but not on IPv6.  The latter
511  * advertises the service on all IPv4 and IPv6 addresses.
512  */
513 int rpcb_v4_register(const u32 program, const u32 version,
514 		     const struct sockaddr *address, const char *netid)
515 {
516 	struct rpcbind_args map = {
517 		.r_prog		= program,
518 		.r_vers		= version,
519 		.r_netid	= netid,
520 		.r_owner	= RPCB_OWNER_STRING,
521 	};
522 	struct rpc_message msg = {
523 		.rpc_argp	= &map,
524 	};
525 	int error;
526 
527 	error = rpcb_create_local();
528 	if (error)
529 		return error;
530 	if (rpcb_local_clnt4 == NULL)
531 		return -EPROTONOSUPPORT;
532 
533 	if (address == NULL)
534 		return rpcb_unregister_all_protofamilies(&msg);
535 
536 	switch (address->sa_family) {
537 	case AF_INET:
538 		return rpcb_register_inet4(address, &msg);
539 	case AF_INET6:
540 		return rpcb_register_inet6(address, &msg);
541 	}
542 
543 	return -EAFNOSUPPORT;
544 }
545 
546 static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt, struct rpcbind_args *map, struct rpc_procinfo *proc)
547 {
548 	struct rpc_message msg = {
549 		.rpc_proc = proc,
550 		.rpc_argp = map,
551 		.rpc_resp = map,
552 	};
553 	struct rpc_task_setup task_setup_data = {
554 		.rpc_client = rpcb_clnt,
555 		.rpc_message = &msg,
556 		.callback_ops = &rpcb_getport_ops,
557 		.callback_data = map,
558 		.flags = RPC_TASK_ASYNC | RPC_TASK_SOFTCONN,
559 	};
560 
561 	return rpc_run_task(&task_setup_data);
562 }
563 
564 /*
565  * In the case where rpc clients have been cloned, we want to make
566  * sure that we use the program number/version etc of the actual
567  * owner of the xprt. To do so, we walk back up the tree of parents
568  * to find whoever created the transport and/or whoever has the
569  * autobind flag set.
570  */
571 static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
572 {
573 	struct rpc_clnt *parent = clnt->cl_parent;
574 
575 	while (parent != clnt) {
576 		if (parent->cl_xprt != clnt->cl_xprt)
577 			break;
578 		if (clnt->cl_autobind)
579 			break;
580 		clnt = parent;
581 		parent = parent->cl_parent;
582 	}
583 	return clnt;
584 }
585 
586 /**
587  * rpcb_getport_async - obtain the port for a given RPC service on a given host
588  * @task: task that is waiting for portmapper request
589  *
590  * This one can be called for an ongoing RPC request, and can be used in
591  * an async (rpciod) context.
592  */
593 void rpcb_getport_async(struct rpc_task *task)
594 {
595 	struct rpc_clnt *clnt;
596 	struct rpc_procinfo *proc;
597 	u32 bind_version;
598 	struct rpc_xprt *xprt;
599 	struct rpc_clnt	*rpcb_clnt;
600 	struct rpcbind_args *map;
601 	struct rpc_task	*child;
602 	struct sockaddr_storage addr;
603 	struct sockaddr *sap = (struct sockaddr *)&addr;
604 	size_t salen;
605 	int status;
606 
607 	clnt = rpcb_find_transport_owner(task->tk_client);
608 	xprt = clnt->cl_xprt;
609 
610 	dprintk("RPC: %5u %s(%s, %u, %u, %d)\n",
611 		task->tk_pid, __func__,
612 		clnt->cl_server, clnt->cl_prog, clnt->cl_vers, xprt->prot);
613 
614 	/* Put self on the wait queue to ensure we get notified if
615 	 * some other task is already attempting to bind the port */
616 	rpc_sleep_on(&xprt->binding, task, NULL);
617 
618 	if (xprt_test_and_set_binding(xprt)) {
619 		dprintk("RPC: %5u %s: waiting for another binder\n",
620 			task->tk_pid, __func__);
621 		return;
622 	}
623 
624 	/* Someone else may have bound if we slept */
625 	if (xprt_bound(xprt)) {
626 		status = 0;
627 		dprintk("RPC: %5u %s: already bound\n",
628 			task->tk_pid, __func__);
629 		goto bailout_nofree;
630 	}
631 
632 	/* Parent transport's destination address */
633 	salen = rpc_peeraddr(clnt, sap, sizeof(addr));
634 
635 	/* Don't ever use rpcbind v2 for AF_INET6 requests */
636 	switch (sap->sa_family) {
637 	case AF_INET:
638 		proc = rpcb_next_version[xprt->bind_index].rpc_proc;
639 		bind_version = rpcb_next_version[xprt->bind_index].rpc_vers;
640 		break;
641 	case AF_INET6:
642 		proc = rpcb_next_version6[xprt->bind_index].rpc_proc;
643 		bind_version = rpcb_next_version6[xprt->bind_index].rpc_vers;
644 		break;
645 	default:
646 		status = -EAFNOSUPPORT;
647 		dprintk("RPC: %5u %s: bad address family\n",
648 				task->tk_pid, __func__);
649 		goto bailout_nofree;
650 	}
651 	if (proc == NULL) {
652 		xprt->bind_index = 0;
653 		status = -EPFNOSUPPORT;
654 		dprintk("RPC: %5u %s: no more getport versions available\n",
655 			task->tk_pid, __func__);
656 		goto bailout_nofree;
657 	}
658 
659 	dprintk("RPC: %5u %s: trying rpcbind version %u\n",
660 		task->tk_pid, __func__, bind_version);
661 
662 	rpcb_clnt = rpcb_create(clnt->cl_server, sap, salen, xprt->prot,
663 				bind_version);
664 	if (IS_ERR(rpcb_clnt)) {
665 		status = PTR_ERR(rpcb_clnt);
666 		dprintk("RPC: %5u %s: rpcb_create failed, error %ld\n",
667 			task->tk_pid, __func__, PTR_ERR(rpcb_clnt));
668 		goto bailout_nofree;
669 	}
670 
671 	map = kzalloc(sizeof(struct rpcbind_args), GFP_ATOMIC);
672 	if (!map) {
673 		status = -ENOMEM;
674 		dprintk("RPC: %5u %s: no memory available\n",
675 			task->tk_pid, __func__);
676 		goto bailout_release_client;
677 	}
678 	map->r_prog = clnt->cl_prog;
679 	map->r_vers = clnt->cl_vers;
680 	map->r_prot = xprt->prot;
681 	map->r_port = 0;
682 	map->r_xprt = xprt_get(xprt);
683 	map->r_status = -EIO;
684 
685 	switch (bind_version) {
686 	case RPCBVERS_4:
687 	case RPCBVERS_3:
688 		map->r_netid = rpc_peeraddr2str(clnt, RPC_DISPLAY_NETID);
689 		map->r_addr = rpc_sockaddr2uaddr(sap);
690 		map->r_owner = "";
691 		break;
692 	case RPCBVERS_2:
693 		map->r_addr = NULL;
694 		break;
695 	default:
696 		BUG();
697 	}
698 
699 	child = rpcb_call_async(rpcb_clnt, map, proc);
700 	rpc_release_client(rpcb_clnt);
701 	if (IS_ERR(child)) {
702 		/* rpcb_map_release() has freed the arguments */
703 		dprintk("RPC: %5u %s: rpc_run_task failed\n",
704 			task->tk_pid, __func__);
705 		return;
706 	}
707 
708 	xprt->stat.bind_count++;
709 	rpc_put_task(child);
710 	return;
711 
712 bailout_release_client:
713 	rpc_release_client(rpcb_clnt);
714 bailout_nofree:
715 	rpcb_wake_rpcbind_waiters(xprt, status);
716 	task->tk_status = status;
717 }
718 EXPORT_SYMBOL_GPL(rpcb_getport_async);
719 
720 /*
721  * Rpcbind child task calls this callback via tk_exit.
722  */
723 static void rpcb_getport_done(struct rpc_task *child, void *data)
724 {
725 	struct rpcbind_args *map = data;
726 	struct rpc_xprt *xprt = map->r_xprt;
727 	int status = child->tk_status;
728 
729 	/* Garbage reply: retry with a lesser rpcbind version */
730 	if (status == -EIO)
731 		status = -EPROTONOSUPPORT;
732 
733 	/* rpcbind server doesn't support this rpcbind protocol version */
734 	if (status == -EPROTONOSUPPORT)
735 		xprt->bind_index++;
736 
737 	if (status < 0) {
738 		/* rpcbind server not available on remote host? */
739 		xprt->ops->set_port(xprt, 0);
740 	} else if (map->r_port == 0) {
741 		/* Requested RPC service wasn't registered on remote host */
742 		xprt->ops->set_port(xprt, 0);
743 		status = -EACCES;
744 	} else {
745 		/* Succeeded */
746 		xprt->ops->set_port(xprt, map->r_port);
747 		xprt_set_bound(xprt);
748 		status = 0;
749 	}
750 
751 	dprintk("RPC: %5u rpcb_getport_done(status %d, port %u)\n",
752 			child->tk_pid, status, map->r_port);
753 
754 	map->r_status = status;
755 }
756 
757 /*
758  * XDR functions for rpcbind
759  */
760 
761 static void rpcb_enc_mapping(struct rpc_rqst *req, struct xdr_stream *xdr,
762 			     const struct rpcbind_args *rpcb)
763 {
764 	struct rpc_task *task = req->rq_task;
765 	__be32 *p;
766 
767 	dprintk("RPC: %5u encoding PMAP_%s call (%u, %u, %d, %u)\n",
768 			task->tk_pid, task->tk_msg.rpc_proc->p_name,
769 			rpcb->r_prog, rpcb->r_vers, rpcb->r_prot, rpcb->r_port);
770 
771 	p = xdr_reserve_space(xdr, RPCB_mappingargs_sz << 2);
772 	*p++ = cpu_to_be32(rpcb->r_prog);
773 	*p++ = cpu_to_be32(rpcb->r_vers);
774 	*p++ = cpu_to_be32(rpcb->r_prot);
775 	*p   = cpu_to_be32(rpcb->r_port);
776 }
777 
778 static int rpcb_dec_getport(struct rpc_rqst *req, struct xdr_stream *xdr,
779 			    struct rpcbind_args *rpcb)
780 {
781 	struct rpc_task *task = req->rq_task;
782 	unsigned long port;
783 	__be32 *p;
784 
785 	rpcb->r_port = 0;
786 
787 	p = xdr_inline_decode(xdr, 4);
788 	if (unlikely(p == NULL))
789 		return -EIO;
790 
791 	port = be32_to_cpup(p);
792 	dprintk("RPC: %5u PMAP_%s result: %lu\n", task->tk_pid,
793 			task->tk_msg.rpc_proc->p_name, port);
794 	if (unlikely(port > USHRT_MAX))
795 		return -EIO;
796 
797 	rpcb->r_port = port;
798 	return 0;
799 }
800 
801 static int rpcb_dec_set(struct rpc_rqst *req, struct xdr_stream *xdr,
802 			unsigned int *boolp)
803 {
804 	struct rpc_task *task = req->rq_task;
805 	__be32 *p;
806 
807 	p = xdr_inline_decode(xdr, 4);
808 	if (unlikely(p == NULL))
809 		return -EIO;
810 
811 	*boolp = 0;
812 	if (*p != xdr_zero)
813 		*boolp = 1;
814 
815 	dprintk("RPC: %5u RPCB_%s call %s\n",
816 			task->tk_pid, task->tk_msg.rpc_proc->p_name,
817 			(*boolp ? "succeeded" : "failed"));
818 	return 0;
819 }
820 
821 static void encode_rpcb_string(struct xdr_stream *xdr, const char *string,
822 			       const u32 maxstrlen)
823 {
824 	__be32 *p;
825 	u32 len;
826 
827 	len = strlen(string);
828 	BUG_ON(len > maxstrlen);
829 	p = xdr_reserve_space(xdr, 4 + len);
830 	xdr_encode_opaque(p, string, len);
831 }
832 
833 static void rpcb_enc_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
834 			     const struct rpcbind_args *rpcb)
835 {
836 	struct rpc_task *task = req->rq_task;
837 	__be32 *p;
838 
839 	dprintk("RPC: %5u encoding RPCB_%s call (%u, %u, '%s', '%s')\n",
840 			task->tk_pid, task->tk_msg.rpc_proc->p_name,
841 			rpcb->r_prog, rpcb->r_vers,
842 			rpcb->r_netid, rpcb->r_addr);
843 
844 	p = xdr_reserve_space(xdr, (RPCB_program_sz + RPCB_version_sz) << 2);
845 	*p++ = cpu_to_be32(rpcb->r_prog);
846 	*p = cpu_to_be32(rpcb->r_vers);
847 
848 	encode_rpcb_string(xdr, rpcb->r_netid, RPCBIND_MAXNETIDLEN);
849 	encode_rpcb_string(xdr, rpcb->r_addr, RPCBIND_MAXUADDRLEN);
850 	encode_rpcb_string(xdr, rpcb->r_owner, RPCB_MAXOWNERLEN);
851 }
852 
853 static int rpcb_dec_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
854 			    struct rpcbind_args *rpcb)
855 {
856 	struct sockaddr_storage address;
857 	struct sockaddr *sap = (struct sockaddr *)&address;
858 	struct rpc_task *task = req->rq_task;
859 	__be32 *p;
860 	u32 len;
861 
862 	rpcb->r_port = 0;
863 
864 	p = xdr_inline_decode(xdr, 4);
865 	if (unlikely(p == NULL))
866 		goto out_fail;
867 	len = be32_to_cpup(p);
868 
869 	/*
870 	 * If the returned universal address is a null string,
871 	 * the requested RPC service was not registered.
872 	 */
873 	if (len == 0) {
874 		dprintk("RPC: %5u RPCB reply: program not registered\n",
875 				task->tk_pid);
876 		return 0;
877 	}
878 
879 	if (unlikely(len > RPCBIND_MAXUADDRLEN))
880 		goto out_fail;
881 
882 	p = xdr_inline_decode(xdr, len);
883 	if (unlikely(p == NULL))
884 		goto out_fail;
885 	dprintk("RPC: %5u RPCB_%s reply: %s\n", task->tk_pid,
886 			task->tk_msg.rpc_proc->p_name, (char *)p);
887 
888 	if (rpc_uaddr2sockaddr((char *)p, len, sap, sizeof(address)) == 0)
889 		goto out_fail;
890 	rpcb->r_port = rpc_get_port(sap);
891 
892 	return 0;
893 
894 out_fail:
895 	dprintk("RPC: %5u malformed RPCB_%s reply\n",
896 			task->tk_pid, task->tk_msg.rpc_proc->p_name);
897 	return -EIO;
898 }
899 
900 /*
901  * Not all rpcbind procedures described in RFC 1833 are implemented
902  * since the Linux kernel RPC code requires only these.
903  */
904 
905 static struct rpc_procinfo rpcb_procedures2[] = {
906 	[RPCBPROC_SET] = {
907 		.p_proc		= RPCBPROC_SET,
908 		.p_encode	= (kxdreproc_t)rpcb_enc_mapping,
909 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
910 		.p_arglen	= RPCB_mappingargs_sz,
911 		.p_replen	= RPCB_setres_sz,
912 		.p_statidx	= RPCBPROC_SET,
913 		.p_timer	= 0,
914 		.p_name		= "SET",
915 	},
916 	[RPCBPROC_UNSET] = {
917 		.p_proc		= RPCBPROC_UNSET,
918 		.p_encode	= (kxdreproc_t)rpcb_enc_mapping,
919 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
920 		.p_arglen	= RPCB_mappingargs_sz,
921 		.p_replen	= RPCB_setres_sz,
922 		.p_statidx	= RPCBPROC_UNSET,
923 		.p_timer	= 0,
924 		.p_name		= "UNSET",
925 	},
926 	[RPCBPROC_GETPORT] = {
927 		.p_proc		= RPCBPROC_GETPORT,
928 		.p_encode	= (kxdreproc_t)rpcb_enc_mapping,
929 		.p_decode	= (kxdrdproc_t)rpcb_dec_getport,
930 		.p_arglen	= RPCB_mappingargs_sz,
931 		.p_replen	= RPCB_getportres_sz,
932 		.p_statidx	= RPCBPROC_GETPORT,
933 		.p_timer	= 0,
934 		.p_name		= "GETPORT",
935 	},
936 };
937 
938 static struct rpc_procinfo rpcb_procedures3[] = {
939 	[RPCBPROC_SET] = {
940 		.p_proc		= RPCBPROC_SET,
941 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
942 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
943 		.p_arglen	= RPCB_getaddrargs_sz,
944 		.p_replen	= RPCB_setres_sz,
945 		.p_statidx	= RPCBPROC_SET,
946 		.p_timer	= 0,
947 		.p_name		= "SET",
948 	},
949 	[RPCBPROC_UNSET] = {
950 		.p_proc		= RPCBPROC_UNSET,
951 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
952 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
953 		.p_arglen	= RPCB_getaddrargs_sz,
954 		.p_replen	= RPCB_setres_sz,
955 		.p_statidx	= RPCBPROC_UNSET,
956 		.p_timer	= 0,
957 		.p_name		= "UNSET",
958 	},
959 	[RPCBPROC_GETADDR] = {
960 		.p_proc		= RPCBPROC_GETADDR,
961 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
962 		.p_decode	= (kxdrdproc_t)rpcb_dec_getaddr,
963 		.p_arglen	= RPCB_getaddrargs_sz,
964 		.p_replen	= RPCB_getaddrres_sz,
965 		.p_statidx	= RPCBPROC_GETADDR,
966 		.p_timer	= 0,
967 		.p_name		= "GETADDR",
968 	},
969 };
970 
971 static struct rpc_procinfo rpcb_procedures4[] = {
972 	[RPCBPROC_SET] = {
973 		.p_proc		= RPCBPROC_SET,
974 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
975 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
976 		.p_arglen	= RPCB_getaddrargs_sz,
977 		.p_replen	= RPCB_setres_sz,
978 		.p_statidx	= RPCBPROC_SET,
979 		.p_timer	= 0,
980 		.p_name		= "SET",
981 	},
982 	[RPCBPROC_UNSET] = {
983 		.p_proc		= RPCBPROC_UNSET,
984 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
985 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
986 		.p_arglen	= RPCB_getaddrargs_sz,
987 		.p_replen	= RPCB_setres_sz,
988 		.p_statidx	= RPCBPROC_UNSET,
989 		.p_timer	= 0,
990 		.p_name		= "UNSET",
991 	},
992 	[RPCBPROC_GETADDR] = {
993 		.p_proc		= RPCBPROC_GETADDR,
994 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
995 		.p_decode	= (kxdrdproc_t)rpcb_dec_getaddr,
996 		.p_arglen	= RPCB_getaddrargs_sz,
997 		.p_replen	= RPCB_getaddrres_sz,
998 		.p_statidx	= RPCBPROC_GETADDR,
999 		.p_timer	= 0,
1000 		.p_name		= "GETADDR",
1001 	},
1002 };
1003 
1004 static struct rpcb_info rpcb_next_version[] = {
1005 	{
1006 		.rpc_vers	= RPCBVERS_2,
1007 		.rpc_proc	= &rpcb_procedures2[RPCBPROC_GETPORT],
1008 	},
1009 	{
1010 		.rpc_proc	= NULL,
1011 	},
1012 };
1013 
1014 static struct rpcb_info rpcb_next_version6[] = {
1015 	{
1016 		.rpc_vers	= RPCBVERS_4,
1017 		.rpc_proc	= &rpcb_procedures4[RPCBPROC_GETADDR],
1018 	},
1019 	{
1020 		.rpc_vers	= RPCBVERS_3,
1021 		.rpc_proc	= &rpcb_procedures3[RPCBPROC_GETADDR],
1022 	},
1023 	{
1024 		.rpc_proc	= NULL,
1025 	},
1026 };
1027 
1028 static struct rpc_version rpcb_version2 = {
1029 	.number		= RPCBVERS_2,
1030 	.nrprocs	= ARRAY_SIZE(rpcb_procedures2),
1031 	.procs		= rpcb_procedures2
1032 };
1033 
1034 static struct rpc_version rpcb_version3 = {
1035 	.number		= RPCBVERS_3,
1036 	.nrprocs	= ARRAY_SIZE(rpcb_procedures3),
1037 	.procs		= rpcb_procedures3
1038 };
1039 
1040 static struct rpc_version rpcb_version4 = {
1041 	.number		= RPCBVERS_4,
1042 	.nrprocs	= ARRAY_SIZE(rpcb_procedures4),
1043 	.procs		= rpcb_procedures4
1044 };
1045 
1046 static struct rpc_version *rpcb_version[] = {
1047 	NULL,
1048 	NULL,
1049 	&rpcb_version2,
1050 	&rpcb_version3,
1051 	&rpcb_version4
1052 };
1053 
1054 static struct rpc_stat rpcb_stats;
1055 
1056 static struct rpc_program rpcb_program = {
1057 	.name		= "rpcbind",
1058 	.number		= RPCBIND_PROGRAM,
1059 	.nrvers		= ARRAY_SIZE(rpcb_version),
1060 	.version	= rpcb_version,
1061 	.stats		= &rpcb_stats,
1062 };
1063 
1064 /**
1065  * cleanup_rpcb_clnt - remove xprtsock's sysctls, unregister
1066  *
1067  */
1068 void cleanup_rpcb_clnt(void)
1069 {
1070 	if (rpcb_local_clnt4)
1071 		rpc_shutdown_client(rpcb_local_clnt4);
1072 	if (rpcb_local_clnt)
1073 		rpc_shutdown_client(rpcb_local_clnt);
1074 }
1075