xref: /linux/net/sunrpc/rpcb_clnt.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
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/in.h>
20 #include <linux/in6.h>
21 #include <linux/kernel.h>
22 #include <linux/errno.h>
23 #include <linux/mutex.h>
24 #include <linux/slab.h>
25 #include <net/ipv6.h>
26 
27 #include <linux/sunrpc/clnt.h>
28 #include <linux/sunrpc/sched.h>
29 #include <linux/sunrpc/xprtsock.h>
30 
31 #ifdef RPC_DEBUG
32 # define RPCDBG_FACILITY	RPCDBG_BIND
33 #endif
34 
35 #define RPCBIND_PROGRAM		(100000u)
36 #define RPCBIND_PORT		(111u)
37 
38 #define RPCBVERS_2		(2u)
39 #define RPCBVERS_3		(3u)
40 #define RPCBVERS_4		(4u)
41 
42 enum {
43 	RPCBPROC_NULL,
44 	RPCBPROC_SET,
45 	RPCBPROC_UNSET,
46 	RPCBPROC_GETPORT,
47 	RPCBPROC_GETADDR = 3,		/* alias for GETPORT */
48 	RPCBPROC_DUMP,
49 	RPCBPROC_CALLIT,
50 	RPCBPROC_BCAST = 5,		/* alias for CALLIT */
51 	RPCBPROC_GETTIME,
52 	RPCBPROC_UADDR2TADDR,
53 	RPCBPROC_TADDR2UADDR,
54 	RPCBPROC_GETVERSADDR,
55 	RPCBPROC_INDIRECT,
56 	RPCBPROC_GETADDRLIST,
57 	RPCBPROC_GETSTAT,
58 };
59 
60 #define RPCB_HIGHPROC_2		RPCBPROC_CALLIT
61 #define RPCB_HIGHPROC_3		RPCBPROC_TADDR2UADDR
62 #define RPCB_HIGHPROC_4		RPCBPROC_GETSTAT
63 
64 /*
65  * r_owner
66  *
67  * The "owner" is allowed to unset a service in the rpcbind database.
68  *
69  * For AF_LOCAL SET/UNSET requests, rpcbind treats this string as a
70  * UID which it maps to a local user name via a password lookup.
71  * In all other cases it is ignored.
72  *
73  * For SET/UNSET requests, user space provides a value, even for
74  * network requests, and GETADDR uses an empty string.  We follow
75  * those precedents here.
76  */
77 #define RPCB_OWNER_STRING	"0"
78 #define RPCB_MAXOWNERLEN	sizeof(RPCB_OWNER_STRING)
79 
80 /*
81  * XDR data type sizes
82  */
83 #define RPCB_program_sz		(1)
84 #define RPCB_version_sz		(1)
85 #define RPCB_protocol_sz	(1)
86 #define RPCB_port_sz		(1)
87 #define RPCB_boolean_sz		(1)
88 
89 #define RPCB_netid_sz		(1 + XDR_QUADLEN(RPCBIND_MAXNETIDLEN))
90 #define RPCB_addr_sz		(1 + XDR_QUADLEN(RPCBIND_MAXUADDRLEN))
91 #define RPCB_ownerstring_sz	(1 + XDR_QUADLEN(RPCB_MAXOWNERLEN))
92 
93 /*
94  * XDR argument and result sizes
95  */
96 #define RPCB_mappingargs_sz	(RPCB_program_sz + RPCB_version_sz + \
97 				RPCB_protocol_sz + RPCB_port_sz)
98 #define RPCB_getaddrargs_sz	(RPCB_program_sz + RPCB_version_sz + \
99 				RPCB_netid_sz + RPCB_addr_sz + \
100 				RPCB_ownerstring_sz)
101 
102 #define RPCB_getportres_sz	RPCB_port_sz
103 #define RPCB_setres_sz		RPCB_boolean_sz
104 
105 /*
106  * Note that RFC 1833 does not put any size restrictions on the
107  * address string returned by the remote rpcbind database.
108  */
109 #define RPCB_getaddrres_sz	RPCB_addr_sz
110 
111 static void			rpcb_getport_done(struct rpc_task *, void *);
112 static void			rpcb_map_release(void *data);
113 static struct rpc_program	rpcb_program;
114 
115 static struct rpc_clnt *	rpcb_local_clnt;
116 static struct rpc_clnt *	rpcb_local_clnt4;
117 
118 struct rpcbind_args {
119 	struct rpc_xprt *	r_xprt;
120 
121 	u32			r_prog;
122 	u32			r_vers;
123 	u32			r_prot;
124 	unsigned short		r_port;
125 	const char *		r_netid;
126 	const char *		r_addr;
127 	const char *		r_owner;
128 
129 	int			r_status;
130 };
131 
132 static struct rpc_procinfo rpcb_procedures2[];
133 static struct rpc_procinfo rpcb_procedures3[];
134 static struct rpc_procinfo rpcb_procedures4[];
135 
136 struct rpcb_info {
137 	u32			rpc_vers;
138 	struct rpc_procinfo *	rpc_proc;
139 };
140 
141 static struct rpcb_info rpcb_next_version[];
142 static struct rpcb_info rpcb_next_version6[];
143 
144 static const struct rpc_call_ops rpcb_getport_ops = {
145 	.rpc_call_done		= rpcb_getport_done,
146 	.rpc_release		= rpcb_map_release,
147 };
148 
149 static void rpcb_wake_rpcbind_waiters(struct rpc_xprt *xprt, int status)
150 {
151 	xprt_clear_binding(xprt);
152 	rpc_wake_up_status(&xprt->binding, status);
153 }
154 
155 static void rpcb_map_release(void *data)
156 {
157 	struct rpcbind_args *map = data;
158 
159 	rpcb_wake_rpcbind_waiters(map->r_xprt, map->r_status);
160 	xprt_put(map->r_xprt);
161 	kfree(map->r_addr);
162 	kfree(map);
163 }
164 
165 static const struct sockaddr_in rpcb_inaddr_loopback = {
166 	.sin_family		= AF_INET,
167 	.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
168 	.sin_port		= htons(RPCBIND_PORT),
169 };
170 
171 static DEFINE_MUTEX(rpcb_create_local_mutex);
172 
173 /*
174  * Returns zero on success, otherwise a negative errno value
175  * is returned.
176  */
177 static int rpcb_create_local(void)
178 {
179 	struct rpc_create_args args = {
180 		.protocol	= XPRT_TRANSPORT_TCP,
181 		.address	= (struct sockaddr *)&rpcb_inaddr_loopback,
182 		.addrsize	= sizeof(rpcb_inaddr_loopback),
183 		.servername	= "localhost",
184 		.program	= &rpcb_program,
185 		.version	= RPCBVERS_2,
186 		.authflavor	= RPC_AUTH_UNIX,
187 		.flags		= RPC_CLNT_CREATE_NOPING,
188 	};
189 	struct rpc_clnt *clnt, *clnt4;
190 	int result = 0;
191 
192 	if (rpcb_local_clnt)
193 		return result;
194 
195 	mutex_lock(&rpcb_create_local_mutex);
196 	if (rpcb_local_clnt)
197 		goto out;
198 
199 	clnt = rpc_create(&args);
200 	if (IS_ERR(clnt)) {
201 		dprintk("RPC:       failed to create local rpcbind "
202 				"client (errno %ld).\n", PTR_ERR(clnt));
203 		result = -PTR_ERR(clnt);
204 		goto out;
205 	}
206 
207 	/*
208 	 * This results in an RPC ping.  On systems running portmapper,
209 	 * the v4 ping will fail.  Proceed anyway, but disallow rpcb
210 	 * v4 upcalls.
211 	 */
212 	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
213 	if (IS_ERR(clnt4)) {
214 		dprintk("RPC:       failed to create local rpcbind v4 "
215 				"cleint (errno %ld).\n", PTR_ERR(clnt4));
216 		clnt4 = NULL;
217 	}
218 
219 	rpcb_local_clnt = clnt;
220 	rpcb_local_clnt4 = clnt4;
221 
222 out:
223 	mutex_unlock(&rpcb_create_local_mutex);
224 	return result;
225 }
226 
227 static struct rpc_clnt *rpcb_create(char *hostname, struct sockaddr *srvaddr,
228 				    size_t salen, int proto, u32 version)
229 {
230 	struct rpc_create_args args = {
231 		.protocol	= proto,
232 		.address	= srvaddr,
233 		.addrsize	= salen,
234 		.servername	= hostname,
235 		.program	= &rpcb_program,
236 		.version	= version,
237 		.authflavor	= RPC_AUTH_UNIX,
238 		.flags		= (RPC_CLNT_CREATE_NOPING |
239 					RPC_CLNT_CREATE_NONPRIVPORT),
240 	};
241 
242 	switch (srvaddr->sa_family) {
243 	case AF_INET:
244 		((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
245 		break;
246 	case AF_INET6:
247 		((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
248 		break;
249 	default:
250 		return NULL;
251 	}
252 
253 	return rpc_create(&args);
254 }
255 
256 static int rpcb_register_call(struct rpc_clnt *clnt, struct rpc_message *msg)
257 {
258 	int result, error = 0;
259 
260 	msg->rpc_resp = &result;
261 
262 	error = rpc_call_sync(clnt, msg, RPC_TASK_SOFTCONN);
263 	if (error < 0) {
264 		dprintk("RPC:       failed to contact local rpcbind "
265 				"server (errno %d).\n", -error);
266 		return error;
267 	}
268 
269 	if (!result)
270 		return -EACCES;
271 	return 0;
272 }
273 
274 /**
275  * rpcb_register - set or unset a port registration with the local rpcbind svc
276  * @prog: RPC program number to bind
277  * @vers: RPC version number to bind
278  * @prot: transport protocol to register
279  * @port: port value to register
280  *
281  * Returns zero if the registration request was dispatched successfully
282  * and the rpcbind daemon returned success.  Otherwise, returns an errno
283  * value that reflects the nature of the error (request could not be
284  * dispatched, timed out, or rpcbind returned an error).
285  *
286  * RPC services invoke this function to advertise their contact
287  * information via the system's rpcbind daemon.  RPC services
288  * invoke this function once for each [program, version, transport]
289  * tuple they wish to advertise.
290  *
291  * Callers may also unregister RPC services that are no longer
292  * available by setting the passed-in port to zero.  This removes
293  * all registered transports for [program, version] from the local
294  * rpcbind database.
295  *
296  * This function uses rpcbind protocol version 2 to contact the
297  * local rpcbind daemon.
298  *
299  * Registration works over both AF_INET and AF_INET6, and services
300  * registered via this function are advertised as available for any
301  * address.  If the local rpcbind daemon is listening on AF_INET6,
302  * services registered via this function will be advertised on
303  * IN6ADDR_ANY (ie available for all AF_INET and AF_INET6
304  * addresses).
305  */
306 int rpcb_register(u32 prog, u32 vers, int prot, unsigned short port)
307 {
308 	struct rpcbind_args map = {
309 		.r_prog		= prog,
310 		.r_vers		= vers,
311 		.r_prot		= prot,
312 		.r_port		= port,
313 	};
314 	struct rpc_message msg = {
315 		.rpc_argp	= &map,
316 	};
317 	int error;
318 
319 	error = rpcb_create_local();
320 	if (error)
321 		return error;
322 
323 	dprintk("RPC:       %sregistering (%u, %u, %d, %u) with local "
324 			"rpcbind\n", (port ? "" : "un"),
325 			prog, vers, prot, port);
326 
327 	msg.rpc_proc = &rpcb_procedures2[RPCBPROC_UNSET];
328 	if (port)
329 		msg.rpc_proc = &rpcb_procedures2[RPCBPROC_SET];
330 
331 	return rpcb_register_call(rpcb_local_clnt, &msg);
332 }
333 
334 /*
335  * Fill in AF_INET family-specific arguments to register
336  */
337 static int rpcb_register_inet4(const struct sockaddr *sap,
338 			       struct rpc_message *msg)
339 {
340 	const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
341 	struct rpcbind_args *map = msg->rpc_argp;
342 	unsigned short port = ntohs(sin->sin_port);
343 	int result;
344 
345 	map->r_addr = rpc_sockaddr2uaddr(sap);
346 
347 	dprintk("RPC:       %sregistering [%u, %u, %s, '%s'] with "
348 		"local rpcbind\n", (port ? "" : "un"),
349 			map->r_prog, map->r_vers,
350 			map->r_addr, map->r_netid);
351 
352 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
353 	if (port)
354 		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
355 
356 	result = rpcb_register_call(rpcb_local_clnt4, msg);
357 	kfree(map->r_addr);
358 	return result;
359 }
360 
361 /*
362  * Fill in AF_INET6 family-specific arguments to register
363  */
364 static int rpcb_register_inet6(const struct sockaddr *sap,
365 			       struct rpc_message *msg)
366 {
367 	const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)sap;
368 	struct rpcbind_args *map = msg->rpc_argp;
369 	unsigned short port = ntohs(sin6->sin6_port);
370 	int result;
371 
372 	map->r_addr = rpc_sockaddr2uaddr(sap);
373 
374 	dprintk("RPC:       %sregistering [%u, %u, %s, '%s'] with "
375 		"local rpcbind\n", (port ? "" : "un"),
376 			map->r_prog, map->r_vers,
377 			map->r_addr, map->r_netid);
378 
379 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
380 	if (port)
381 		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
382 
383 	result = rpcb_register_call(rpcb_local_clnt4, msg);
384 	kfree(map->r_addr);
385 	return result;
386 }
387 
388 static int rpcb_unregister_all_protofamilies(struct rpc_message *msg)
389 {
390 	struct rpcbind_args *map = msg->rpc_argp;
391 
392 	dprintk("RPC:       unregistering [%u, %u, '%s'] with "
393 		"local rpcbind\n",
394 			map->r_prog, map->r_vers, map->r_netid);
395 
396 	map->r_addr = "";
397 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
398 
399 	return rpcb_register_call(rpcb_local_clnt4, msg);
400 }
401 
402 /**
403  * rpcb_v4_register - set or unset a port registration with the local rpcbind
404  * @program: RPC program number of service to (un)register
405  * @version: RPC version number of service to (un)register
406  * @address: address family, IP address, and port to (un)register
407  * @netid: netid of transport protocol to (un)register
408  *
409  * Returns zero if the registration request was dispatched successfully
410  * and the rpcbind daemon returned success.  Otherwise, returns an errno
411  * value that reflects the nature of the error (request could not be
412  * dispatched, timed out, or rpcbind returned an error).
413  *
414  * RPC services invoke this function to advertise their contact
415  * information via the system's rpcbind daemon.  RPC services
416  * invoke this function once for each [program, version, address,
417  * netid] tuple they wish to advertise.
418  *
419  * Callers may also unregister RPC services that are registered at a
420  * specific address by setting the port number in @address to zero.
421  * They may unregister all registered protocol families at once for
422  * a service by passing a NULL @address argument.  If @netid is ""
423  * then all netids for [program, version, address] are unregistered.
424  *
425  * This function uses rpcbind protocol version 4 to contact the
426  * local rpcbind daemon.  The local rpcbind daemon must support
427  * version 4 of the rpcbind protocol in order for these functions
428  * to register a service successfully.
429  *
430  * Supported netids include "udp" and "tcp" for UDP and TCP over
431  * IPv4, and "udp6" and "tcp6" for UDP and TCP over IPv6,
432  * respectively.
433  *
434  * The contents of @address determine the address family and the
435  * port to be registered.  The usual practice is to pass INADDR_ANY
436  * as the raw address, but specifying a non-zero address is also
437  * supported by this API if the caller wishes to advertise an RPC
438  * service on a specific network interface.
439  *
440  * Note that passing in INADDR_ANY does not create the same service
441  * registration as IN6ADDR_ANY.  The former advertises an RPC
442  * service on any IPv4 address, but not on IPv6.  The latter
443  * advertises the service on all IPv4 and IPv6 addresses.
444  */
445 int rpcb_v4_register(const u32 program, const u32 version,
446 		     const struct sockaddr *address, const char *netid)
447 {
448 	struct rpcbind_args map = {
449 		.r_prog		= program,
450 		.r_vers		= version,
451 		.r_netid	= netid,
452 		.r_owner	= RPCB_OWNER_STRING,
453 	};
454 	struct rpc_message msg = {
455 		.rpc_argp	= &map,
456 	};
457 	int error;
458 
459 	error = rpcb_create_local();
460 	if (error)
461 		return error;
462 	if (rpcb_local_clnt4 == NULL)
463 		return -EPROTONOSUPPORT;
464 
465 	if (address == NULL)
466 		return rpcb_unregister_all_protofamilies(&msg);
467 
468 	switch (address->sa_family) {
469 	case AF_INET:
470 		return rpcb_register_inet4(address, &msg);
471 	case AF_INET6:
472 		return rpcb_register_inet6(address, &msg);
473 	}
474 
475 	return -EAFNOSUPPORT;
476 }
477 
478 /**
479  * rpcb_getport_sync - obtain the port for an RPC service on a given host
480  * @sin: address of remote peer
481  * @prog: RPC program number to bind
482  * @vers: RPC version number to bind
483  * @prot: transport protocol to use to make this request
484  *
485  * Return value is the requested advertised port number,
486  * or a negative errno value.
487  *
488  * Called from outside the RPC client in a synchronous task context.
489  * Uses default timeout parameters specified by underlying transport.
490  *
491  * XXX: Needs to support IPv6
492  */
493 int rpcb_getport_sync(struct sockaddr_in *sin, u32 prog, u32 vers, int prot)
494 {
495 	struct rpcbind_args map = {
496 		.r_prog		= prog,
497 		.r_vers		= vers,
498 		.r_prot		= prot,
499 		.r_port		= 0,
500 	};
501 	struct rpc_message msg = {
502 		.rpc_proc	= &rpcb_procedures2[RPCBPROC_GETPORT],
503 		.rpc_argp	= &map,
504 		.rpc_resp	= &map,
505 	};
506 	struct rpc_clnt	*rpcb_clnt;
507 	int status;
508 
509 	dprintk("RPC:       %s(%pI4, %u, %u, %d)\n",
510 		__func__, &sin->sin_addr.s_addr, prog, vers, prot);
511 
512 	rpcb_clnt = rpcb_create(NULL, (struct sockaddr *)sin,
513 				sizeof(*sin), prot, RPCBVERS_2);
514 	if (IS_ERR(rpcb_clnt))
515 		return PTR_ERR(rpcb_clnt);
516 
517 	status = rpc_call_sync(rpcb_clnt, &msg, 0);
518 	rpc_shutdown_client(rpcb_clnt);
519 
520 	if (status >= 0) {
521 		if (map.r_port != 0)
522 			return map.r_port;
523 		status = -EACCES;
524 	}
525 	return status;
526 }
527 EXPORT_SYMBOL_GPL(rpcb_getport_sync);
528 
529 static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt, struct rpcbind_args *map, struct rpc_procinfo *proc)
530 {
531 	struct rpc_message msg = {
532 		.rpc_proc = proc,
533 		.rpc_argp = map,
534 		.rpc_resp = map,
535 	};
536 	struct rpc_task_setup task_setup_data = {
537 		.rpc_client = rpcb_clnt,
538 		.rpc_message = &msg,
539 		.callback_ops = &rpcb_getport_ops,
540 		.callback_data = map,
541 		.flags = RPC_TASK_ASYNC | RPC_TASK_SOFTCONN,
542 	};
543 
544 	return rpc_run_task(&task_setup_data);
545 }
546 
547 /*
548  * In the case where rpc clients have been cloned, we want to make
549  * sure that we use the program number/version etc of the actual
550  * owner of the xprt. To do so, we walk back up the tree of parents
551  * to find whoever created the transport and/or whoever has the
552  * autobind flag set.
553  */
554 static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
555 {
556 	struct rpc_clnt *parent = clnt->cl_parent;
557 
558 	while (parent != clnt) {
559 		if (parent->cl_xprt != clnt->cl_xprt)
560 			break;
561 		if (clnt->cl_autobind)
562 			break;
563 		clnt = parent;
564 		parent = parent->cl_parent;
565 	}
566 	return clnt;
567 }
568 
569 /**
570  * rpcb_getport_async - obtain the port for a given RPC service on a given host
571  * @task: task that is waiting for portmapper request
572  *
573  * This one can be called for an ongoing RPC request, and can be used in
574  * an async (rpciod) context.
575  */
576 void rpcb_getport_async(struct rpc_task *task)
577 {
578 	struct rpc_clnt *clnt;
579 	struct rpc_procinfo *proc;
580 	u32 bind_version;
581 	struct rpc_xprt *xprt;
582 	struct rpc_clnt	*rpcb_clnt;
583 	static struct rpcbind_args *map;
584 	struct rpc_task	*child;
585 	struct sockaddr_storage addr;
586 	struct sockaddr *sap = (struct sockaddr *)&addr;
587 	size_t salen;
588 	int status;
589 
590 	clnt = rpcb_find_transport_owner(task->tk_client);
591 	xprt = clnt->cl_xprt;
592 
593 	dprintk("RPC: %5u %s(%s, %u, %u, %d)\n",
594 		task->tk_pid, __func__,
595 		clnt->cl_server, clnt->cl_prog, clnt->cl_vers, xprt->prot);
596 
597 	/* Put self on the wait queue to ensure we get notified if
598 	 * some other task is already attempting to bind the port */
599 	rpc_sleep_on(&xprt->binding, task, NULL);
600 
601 	if (xprt_test_and_set_binding(xprt)) {
602 		dprintk("RPC: %5u %s: waiting for another binder\n",
603 			task->tk_pid, __func__);
604 		return;
605 	}
606 
607 	/* Someone else may have bound if we slept */
608 	if (xprt_bound(xprt)) {
609 		status = 0;
610 		dprintk("RPC: %5u %s: already bound\n",
611 			task->tk_pid, __func__);
612 		goto bailout_nofree;
613 	}
614 
615 	/* Parent transport's destination address */
616 	salen = rpc_peeraddr(clnt, sap, sizeof(addr));
617 
618 	/* Don't ever use rpcbind v2 for AF_INET6 requests */
619 	switch (sap->sa_family) {
620 	case AF_INET:
621 		proc = rpcb_next_version[xprt->bind_index].rpc_proc;
622 		bind_version = rpcb_next_version[xprt->bind_index].rpc_vers;
623 		break;
624 	case AF_INET6:
625 		proc = rpcb_next_version6[xprt->bind_index].rpc_proc;
626 		bind_version = rpcb_next_version6[xprt->bind_index].rpc_vers;
627 		break;
628 	default:
629 		status = -EAFNOSUPPORT;
630 		dprintk("RPC: %5u %s: bad address family\n",
631 				task->tk_pid, __func__);
632 		goto bailout_nofree;
633 	}
634 	if (proc == NULL) {
635 		xprt->bind_index = 0;
636 		status = -EPFNOSUPPORT;
637 		dprintk("RPC: %5u %s: no more getport versions available\n",
638 			task->tk_pid, __func__);
639 		goto bailout_nofree;
640 	}
641 
642 	dprintk("RPC: %5u %s: trying rpcbind version %u\n",
643 		task->tk_pid, __func__, bind_version);
644 
645 	rpcb_clnt = rpcb_create(clnt->cl_server, sap, salen, xprt->prot,
646 				bind_version);
647 	if (IS_ERR(rpcb_clnt)) {
648 		status = PTR_ERR(rpcb_clnt);
649 		dprintk("RPC: %5u %s: rpcb_create failed, error %ld\n",
650 			task->tk_pid, __func__, PTR_ERR(rpcb_clnt));
651 		goto bailout_nofree;
652 	}
653 
654 	map = kzalloc(sizeof(struct rpcbind_args), GFP_ATOMIC);
655 	if (!map) {
656 		status = -ENOMEM;
657 		dprintk("RPC: %5u %s: no memory available\n",
658 			task->tk_pid, __func__);
659 		goto bailout_release_client;
660 	}
661 	map->r_prog = clnt->cl_prog;
662 	map->r_vers = clnt->cl_vers;
663 	map->r_prot = xprt->prot;
664 	map->r_port = 0;
665 	map->r_xprt = xprt_get(xprt);
666 	map->r_status = -EIO;
667 
668 	switch (bind_version) {
669 	case RPCBVERS_4:
670 	case RPCBVERS_3:
671 		map->r_netid = rpc_peeraddr2str(clnt, RPC_DISPLAY_NETID);
672 		map->r_addr = rpc_sockaddr2uaddr(sap);
673 		map->r_owner = "";
674 		break;
675 	case RPCBVERS_2:
676 		map->r_addr = NULL;
677 		break;
678 	default:
679 		BUG();
680 	}
681 
682 	child = rpcb_call_async(rpcb_clnt, map, proc);
683 	rpc_release_client(rpcb_clnt);
684 	if (IS_ERR(child)) {
685 		/* rpcb_map_release() has freed the arguments */
686 		dprintk("RPC: %5u %s: rpc_run_task failed\n",
687 			task->tk_pid, __func__);
688 		return;
689 	}
690 
691 	xprt->stat.bind_count++;
692 	rpc_put_task(child);
693 	return;
694 
695 bailout_release_client:
696 	rpc_release_client(rpcb_clnt);
697 bailout_nofree:
698 	rpcb_wake_rpcbind_waiters(xprt, status);
699 	task->tk_status = status;
700 }
701 EXPORT_SYMBOL_GPL(rpcb_getport_async);
702 
703 /*
704  * Rpcbind child task calls this callback via tk_exit.
705  */
706 static void rpcb_getport_done(struct rpc_task *child, void *data)
707 {
708 	struct rpcbind_args *map = data;
709 	struct rpc_xprt *xprt = map->r_xprt;
710 	int status = child->tk_status;
711 
712 	/* Garbage reply: retry with a lesser rpcbind version */
713 	if (status == -EIO)
714 		status = -EPROTONOSUPPORT;
715 
716 	/* rpcbind server doesn't support this rpcbind protocol version */
717 	if (status == -EPROTONOSUPPORT)
718 		xprt->bind_index++;
719 
720 	if (status < 0) {
721 		/* rpcbind server not available on remote host? */
722 		xprt->ops->set_port(xprt, 0);
723 	} else if (map->r_port == 0) {
724 		/* Requested RPC service wasn't registered on remote host */
725 		xprt->ops->set_port(xprt, 0);
726 		status = -EACCES;
727 	} else {
728 		/* Succeeded */
729 		xprt->ops->set_port(xprt, map->r_port);
730 		xprt_set_bound(xprt);
731 		status = 0;
732 	}
733 
734 	dprintk("RPC: %5u rpcb_getport_done(status %d, port %u)\n",
735 			child->tk_pid, status, map->r_port);
736 
737 	map->r_status = status;
738 }
739 
740 /*
741  * XDR functions for rpcbind
742  */
743 
744 static int rpcb_enc_mapping(struct rpc_rqst *req, __be32 *p,
745 			    const struct rpcbind_args *rpcb)
746 {
747 	struct rpc_task *task = req->rq_task;
748 	struct xdr_stream xdr;
749 
750 	dprintk("RPC: %5u encoding PMAP_%s call (%u, %u, %d, %u)\n",
751 			task->tk_pid, task->tk_msg.rpc_proc->p_name,
752 			rpcb->r_prog, rpcb->r_vers, rpcb->r_prot, rpcb->r_port);
753 
754 	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
755 
756 	p = xdr_reserve_space(&xdr, sizeof(__be32) * RPCB_mappingargs_sz);
757 	if (unlikely(p == NULL))
758 		return -EIO;
759 
760 	*p++ = htonl(rpcb->r_prog);
761 	*p++ = htonl(rpcb->r_vers);
762 	*p++ = htonl(rpcb->r_prot);
763 	*p   = htonl(rpcb->r_port);
764 
765 	return 0;
766 }
767 
768 static int rpcb_dec_getport(struct rpc_rqst *req, __be32 *p,
769 			    struct rpcbind_args *rpcb)
770 {
771 	struct rpc_task *task = req->rq_task;
772 	struct xdr_stream xdr;
773 	unsigned long port;
774 
775 	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
776 
777 	rpcb->r_port = 0;
778 
779 	p = xdr_inline_decode(&xdr, sizeof(__be32));
780 	if (unlikely(p == NULL))
781 		return -EIO;
782 
783 	port = ntohl(*p);
784 	dprintk("RPC: %5u PMAP_%s result: %lu\n", task->tk_pid,
785 			task->tk_msg.rpc_proc->p_name, port);
786 	if (unlikely(port > USHRT_MAX))
787 		return -EIO;
788 
789 	rpcb->r_port = port;
790 	return 0;
791 }
792 
793 static int rpcb_dec_set(struct rpc_rqst *req, __be32 *p,
794 			unsigned int *boolp)
795 {
796 	struct rpc_task *task = req->rq_task;
797 	struct xdr_stream xdr;
798 
799 	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
800 
801 	p = xdr_inline_decode(&xdr, sizeof(__be32));
802 	if (unlikely(p == NULL))
803 		return -EIO;
804 
805 	*boolp = 0;
806 	if (*p)
807 		*boolp = 1;
808 
809 	dprintk("RPC: %5u RPCB_%s call %s\n",
810 			task->tk_pid, task->tk_msg.rpc_proc->p_name,
811 			(*boolp ? "succeeded" : "failed"));
812 	return 0;
813 }
814 
815 static int encode_rpcb_string(struct xdr_stream *xdr, const char *string,
816 				const u32 maxstrlen)
817 {
818 	u32 len;
819 	__be32 *p;
820 
821 	if (unlikely(string == NULL))
822 		return -EIO;
823 	len = strlen(string);
824 	if (unlikely(len > maxstrlen))
825 		return -EIO;
826 
827 	p = xdr_reserve_space(xdr, sizeof(__be32) + len);
828 	if (unlikely(p == NULL))
829 		return -EIO;
830 	xdr_encode_opaque(p, string, len);
831 
832 	return 0;
833 }
834 
835 static int rpcb_enc_getaddr(struct rpc_rqst *req, __be32 *p,
836 			    const struct rpcbind_args *rpcb)
837 {
838 	struct rpc_task *task = req->rq_task;
839 	struct xdr_stream xdr;
840 
841 	dprintk("RPC: %5u encoding RPCB_%s call (%u, %u, '%s', '%s')\n",
842 			task->tk_pid, task->tk_msg.rpc_proc->p_name,
843 			rpcb->r_prog, rpcb->r_vers,
844 			rpcb->r_netid, rpcb->r_addr);
845 
846 	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
847 
848 	p = xdr_reserve_space(&xdr,
849 			sizeof(__be32) * (RPCB_program_sz + RPCB_version_sz));
850 	if (unlikely(p == NULL))
851 		return -EIO;
852 	*p++ = htonl(rpcb->r_prog);
853 	*p = htonl(rpcb->r_vers);
854 
855 	if (encode_rpcb_string(&xdr, rpcb->r_netid, RPCBIND_MAXNETIDLEN))
856 		return -EIO;
857 	if (encode_rpcb_string(&xdr, rpcb->r_addr, RPCBIND_MAXUADDRLEN))
858 		return -EIO;
859 	if (encode_rpcb_string(&xdr, rpcb->r_owner, RPCB_MAXOWNERLEN))
860 		return -EIO;
861 
862 	return 0;
863 }
864 
865 static int rpcb_dec_getaddr(struct rpc_rqst *req, __be32 *p,
866 			    struct rpcbind_args *rpcb)
867 {
868 	struct sockaddr_storage address;
869 	struct sockaddr *sap = (struct sockaddr *)&address;
870 	struct rpc_task *task = req->rq_task;
871 	struct xdr_stream xdr;
872 	u32 len;
873 
874 	rpcb->r_port = 0;
875 
876 	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
877 
878 	p = xdr_inline_decode(&xdr, sizeof(__be32));
879 	if (unlikely(p == NULL))
880 		goto out_fail;
881 	len = ntohl(*p);
882 
883 	/*
884 	 * If the returned universal address is a null string,
885 	 * the requested RPC service was not registered.
886 	 */
887 	if (len == 0) {
888 		dprintk("RPC: %5u RPCB reply: program not registered\n",
889 				task->tk_pid);
890 		return 0;
891 	}
892 
893 	if (unlikely(len > RPCBIND_MAXUADDRLEN))
894 		goto out_fail;
895 
896 	p = xdr_inline_decode(&xdr, len);
897 	if (unlikely(p == NULL))
898 		goto out_fail;
899 	dprintk("RPC: %5u RPCB_%s reply: %s\n", task->tk_pid,
900 			task->tk_msg.rpc_proc->p_name, (char *)p);
901 
902 	if (rpc_uaddr2sockaddr((char *)p, len, sap, sizeof(address)) == 0)
903 		goto out_fail;
904 	rpcb->r_port = rpc_get_port(sap);
905 
906 	return 0;
907 
908 out_fail:
909 	dprintk("RPC: %5u malformed RPCB_%s reply\n",
910 			task->tk_pid, task->tk_msg.rpc_proc->p_name);
911 	return -EIO;
912 }
913 
914 /*
915  * Not all rpcbind procedures described in RFC 1833 are implemented
916  * since the Linux kernel RPC code requires only these.
917  */
918 
919 static struct rpc_procinfo rpcb_procedures2[] = {
920 	[RPCBPROC_SET] = {
921 		.p_proc		= RPCBPROC_SET,
922 		.p_encode	= (kxdrproc_t)rpcb_enc_mapping,
923 		.p_decode	= (kxdrproc_t)rpcb_dec_set,
924 		.p_arglen	= RPCB_mappingargs_sz,
925 		.p_replen	= RPCB_setres_sz,
926 		.p_statidx	= RPCBPROC_SET,
927 		.p_timer	= 0,
928 		.p_name		= "SET",
929 	},
930 	[RPCBPROC_UNSET] = {
931 		.p_proc		= RPCBPROC_UNSET,
932 		.p_encode	= (kxdrproc_t)rpcb_enc_mapping,
933 		.p_decode	= (kxdrproc_t)rpcb_dec_set,
934 		.p_arglen	= RPCB_mappingargs_sz,
935 		.p_replen	= RPCB_setres_sz,
936 		.p_statidx	= RPCBPROC_UNSET,
937 		.p_timer	= 0,
938 		.p_name		= "UNSET",
939 	},
940 	[RPCBPROC_GETPORT] = {
941 		.p_proc		= RPCBPROC_GETPORT,
942 		.p_encode	= (kxdrproc_t)rpcb_enc_mapping,
943 		.p_decode	= (kxdrproc_t)rpcb_dec_getport,
944 		.p_arglen	= RPCB_mappingargs_sz,
945 		.p_replen	= RPCB_getportres_sz,
946 		.p_statidx	= RPCBPROC_GETPORT,
947 		.p_timer	= 0,
948 		.p_name		= "GETPORT",
949 	},
950 };
951 
952 static struct rpc_procinfo rpcb_procedures3[] = {
953 	[RPCBPROC_SET] = {
954 		.p_proc		= RPCBPROC_SET,
955 		.p_encode	= (kxdrproc_t)rpcb_enc_getaddr,
956 		.p_decode	= (kxdrproc_t)rpcb_dec_set,
957 		.p_arglen	= RPCB_getaddrargs_sz,
958 		.p_replen	= RPCB_setres_sz,
959 		.p_statidx	= RPCBPROC_SET,
960 		.p_timer	= 0,
961 		.p_name		= "SET",
962 	},
963 	[RPCBPROC_UNSET] = {
964 		.p_proc		= RPCBPROC_UNSET,
965 		.p_encode	= (kxdrproc_t)rpcb_enc_getaddr,
966 		.p_decode	= (kxdrproc_t)rpcb_dec_set,
967 		.p_arglen	= RPCB_getaddrargs_sz,
968 		.p_replen	= RPCB_setres_sz,
969 		.p_statidx	= RPCBPROC_UNSET,
970 		.p_timer	= 0,
971 		.p_name		= "UNSET",
972 	},
973 	[RPCBPROC_GETADDR] = {
974 		.p_proc		= RPCBPROC_GETADDR,
975 		.p_encode	= (kxdrproc_t)rpcb_enc_getaddr,
976 		.p_decode	= (kxdrproc_t)rpcb_dec_getaddr,
977 		.p_arglen	= RPCB_getaddrargs_sz,
978 		.p_replen	= RPCB_getaddrres_sz,
979 		.p_statidx	= RPCBPROC_GETADDR,
980 		.p_timer	= 0,
981 		.p_name		= "GETADDR",
982 	},
983 };
984 
985 static struct rpc_procinfo rpcb_procedures4[] = {
986 	[RPCBPROC_SET] = {
987 		.p_proc		= RPCBPROC_SET,
988 		.p_encode	= (kxdrproc_t)rpcb_enc_getaddr,
989 		.p_decode	= (kxdrproc_t)rpcb_dec_set,
990 		.p_arglen	= RPCB_getaddrargs_sz,
991 		.p_replen	= RPCB_setres_sz,
992 		.p_statidx	= RPCBPROC_SET,
993 		.p_timer	= 0,
994 		.p_name		= "SET",
995 	},
996 	[RPCBPROC_UNSET] = {
997 		.p_proc		= RPCBPROC_UNSET,
998 		.p_encode	= (kxdrproc_t)rpcb_enc_getaddr,
999 		.p_decode	= (kxdrproc_t)rpcb_dec_set,
1000 		.p_arglen	= RPCB_getaddrargs_sz,
1001 		.p_replen	= RPCB_setres_sz,
1002 		.p_statidx	= RPCBPROC_UNSET,
1003 		.p_timer	= 0,
1004 		.p_name		= "UNSET",
1005 	},
1006 	[RPCBPROC_GETADDR] = {
1007 		.p_proc		= RPCBPROC_GETADDR,
1008 		.p_encode	= (kxdrproc_t)rpcb_enc_getaddr,
1009 		.p_decode	= (kxdrproc_t)rpcb_dec_getaddr,
1010 		.p_arglen	= RPCB_getaddrargs_sz,
1011 		.p_replen	= RPCB_getaddrres_sz,
1012 		.p_statidx	= RPCBPROC_GETADDR,
1013 		.p_timer	= 0,
1014 		.p_name		= "GETADDR",
1015 	},
1016 };
1017 
1018 static struct rpcb_info rpcb_next_version[] = {
1019 	{
1020 		.rpc_vers	= RPCBVERS_2,
1021 		.rpc_proc	= &rpcb_procedures2[RPCBPROC_GETPORT],
1022 	},
1023 	{
1024 		.rpc_proc	= NULL,
1025 	},
1026 };
1027 
1028 static struct rpcb_info rpcb_next_version6[] = {
1029 	{
1030 		.rpc_vers	= RPCBVERS_4,
1031 		.rpc_proc	= &rpcb_procedures4[RPCBPROC_GETADDR],
1032 	},
1033 	{
1034 		.rpc_vers	= RPCBVERS_3,
1035 		.rpc_proc	= &rpcb_procedures3[RPCBPROC_GETADDR],
1036 	},
1037 	{
1038 		.rpc_proc	= NULL,
1039 	},
1040 };
1041 
1042 static struct rpc_version rpcb_version2 = {
1043 	.number		= RPCBVERS_2,
1044 	.nrprocs	= RPCB_HIGHPROC_2,
1045 	.procs		= rpcb_procedures2
1046 };
1047 
1048 static struct rpc_version rpcb_version3 = {
1049 	.number		= RPCBVERS_3,
1050 	.nrprocs	= RPCB_HIGHPROC_3,
1051 	.procs		= rpcb_procedures3
1052 };
1053 
1054 static struct rpc_version rpcb_version4 = {
1055 	.number		= RPCBVERS_4,
1056 	.nrprocs	= RPCB_HIGHPROC_4,
1057 	.procs		= rpcb_procedures4
1058 };
1059 
1060 static struct rpc_version *rpcb_version[] = {
1061 	NULL,
1062 	NULL,
1063 	&rpcb_version2,
1064 	&rpcb_version3,
1065 	&rpcb_version4
1066 };
1067 
1068 static struct rpc_stat rpcb_stats;
1069 
1070 static struct rpc_program rpcb_program = {
1071 	.name		= "rpcbind",
1072 	.number		= RPCBIND_PROGRAM,
1073 	.nrvers		= ARRAY_SIZE(rpcb_version),
1074 	.version	= rpcb_version,
1075 	.stats		= &rpcb_stats,
1076 };
1077 
1078 /**
1079  * cleanup_rpcb_clnt - remove xprtsock's sysctls, unregister
1080  *
1081  */
1082 void cleanup_rpcb_clnt(void)
1083 {
1084 	if (rpcb_local_clnt4)
1085 		rpc_shutdown_client(rpcb_local_clnt4);
1086 	if (rpcb_local_clnt)
1087 		rpc_shutdown_client(rpcb_local_clnt);
1088 }
1089