xref: /linux/net/sunrpc/rpcb_clnt.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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/addr.h>
30 #include <linux/sunrpc/sched.h>
31 #include <linux/sunrpc/xprtsock.h>
32 
33 #include "netns.h"
34 
35 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
36 # define RPCDBG_FACILITY	RPCDBG_BIND
37 #endif
38 
39 #define RPCBIND_SOCK_PATHNAME	"/var/run/rpcbind.sock"
40 
41 #define RPCBIND_PROGRAM		(100000u)
42 #define RPCBIND_PORT		(111u)
43 
44 #define RPCBVERS_2		(2u)
45 #define RPCBVERS_3		(3u)
46 #define RPCBVERS_4		(4u)
47 
48 enum {
49 	RPCBPROC_NULL,
50 	RPCBPROC_SET,
51 	RPCBPROC_UNSET,
52 	RPCBPROC_GETPORT,
53 	RPCBPROC_GETADDR = 3,		/* alias for GETPORT */
54 	RPCBPROC_DUMP,
55 	RPCBPROC_CALLIT,
56 	RPCBPROC_BCAST = 5,		/* alias for CALLIT */
57 	RPCBPROC_GETTIME,
58 	RPCBPROC_UADDR2TADDR,
59 	RPCBPROC_TADDR2UADDR,
60 	RPCBPROC_GETVERSADDR,
61 	RPCBPROC_INDIRECT,
62 	RPCBPROC_GETADDRLIST,
63 	RPCBPROC_GETSTAT,
64 };
65 
66 /*
67  * r_owner
68  *
69  * The "owner" is allowed to unset a service in the rpcbind database.
70  *
71  * For AF_LOCAL SET/UNSET requests, rpcbind treats this string as a
72  * UID which it maps to a local user name via a password lookup.
73  * In all other cases it is ignored.
74  *
75  * For SET/UNSET requests, user space provides a value, even for
76  * network requests, and GETADDR uses an empty string.  We follow
77  * those precedents here.
78  */
79 #define RPCB_OWNER_STRING	"0"
80 #define RPCB_MAXOWNERLEN	sizeof(RPCB_OWNER_STRING)
81 
82 /*
83  * XDR data type sizes
84  */
85 #define RPCB_program_sz		(1)
86 #define RPCB_version_sz		(1)
87 #define RPCB_protocol_sz	(1)
88 #define RPCB_port_sz		(1)
89 #define RPCB_boolean_sz		(1)
90 
91 #define RPCB_netid_sz		(1 + XDR_QUADLEN(RPCBIND_MAXNETIDLEN))
92 #define RPCB_addr_sz		(1 + XDR_QUADLEN(RPCBIND_MAXUADDRLEN))
93 #define RPCB_ownerstring_sz	(1 + XDR_QUADLEN(RPCB_MAXOWNERLEN))
94 
95 /*
96  * XDR argument and result sizes
97  */
98 #define RPCB_mappingargs_sz	(RPCB_program_sz + RPCB_version_sz + \
99 				RPCB_protocol_sz + RPCB_port_sz)
100 #define RPCB_getaddrargs_sz	(RPCB_program_sz + RPCB_version_sz + \
101 				RPCB_netid_sz + RPCB_addr_sz + \
102 				RPCB_ownerstring_sz)
103 
104 #define RPCB_getportres_sz	RPCB_port_sz
105 #define RPCB_setres_sz		RPCB_boolean_sz
106 
107 /*
108  * Note that RFC 1833 does not put any size restrictions on the
109  * address string returned by the remote rpcbind database.
110  */
111 #define RPCB_getaddrres_sz	RPCB_addr_sz
112 
113 static void			rpcb_getport_done(struct rpc_task *, void *);
114 static void			rpcb_map_release(void *data);
115 static const struct rpc_program	rpcb_program;
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 const struct rpcb_info rpcb_next_version[];
141 static const 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 static int rpcb_get_local(struct net *net)
165 {
166 	int cnt;
167 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
168 
169 	spin_lock(&sn->rpcb_clnt_lock);
170 	if (sn->rpcb_users)
171 		sn->rpcb_users++;
172 	cnt = sn->rpcb_users;
173 	spin_unlock(&sn->rpcb_clnt_lock);
174 
175 	return cnt;
176 }
177 
178 void rpcb_put_local(struct net *net)
179 {
180 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
181 	struct rpc_clnt *clnt = sn->rpcb_local_clnt;
182 	struct rpc_clnt *clnt4 = sn->rpcb_local_clnt4;
183 	int shutdown = 0;
184 
185 	spin_lock(&sn->rpcb_clnt_lock);
186 	if (sn->rpcb_users) {
187 		if (--sn->rpcb_users == 0) {
188 			sn->rpcb_local_clnt = NULL;
189 			sn->rpcb_local_clnt4 = NULL;
190 		}
191 		shutdown = !sn->rpcb_users;
192 	}
193 	spin_unlock(&sn->rpcb_clnt_lock);
194 
195 	if (shutdown) {
196 		/*
197 		 * cleanup_rpcb_clnt - remove xprtsock's sysctls, unregister
198 		 */
199 		if (clnt4)
200 			rpc_shutdown_client(clnt4);
201 		if (clnt)
202 			rpc_shutdown_client(clnt);
203 	}
204 }
205 
206 static void rpcb_set_local(struct net *net, struct rpc_clnt *clnt,
207 			struct rpc_clnt *clnt4,
208 			bool is_af_local)
209 {
210 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
211 
212 	/* Protected by rpcb_create_local_mutex */
213 	sn->rpcb_local_clnt = clnt;
214 	sn->rpcb_local_clnt4 = clnt4;
215 	sn->rpcb_is_af_local = is_af_local ? 1 : 0;
216 	smp_wmb();
217 	sn->rpcb_users = 1;
218 	dprintk("RPC:       created new rpcb local clients (rpcb_local_clnt: "
219 			"%p, rpcb_local_clnt4: %p) for net %p%s\n",
220 			sn->rpcb_local_clnt, sn->rpcb_local_clnt4,
221 			net, (net == &init_net) ? " (init_net)" : "");
222 }
223 
224 /*
225  * Returns zero on success, otherwise a negative errno value
226  * is returned.
227  */
228 static int rpcb_create_local_unix(struct net *net)
229 {
230 	static const struct sockaddr_un rpcb_localaddr_rpcbind = {
231 		.sun_family		= AF_LOCAL,
232 		.sun_path		= RPCBIND_SOCK_PATHNAME,
233 	};
234 	struct rpc_create_args args = {
235 		.net		= net,
236 		.protocol	= XPRT_TRANSPORT_LOCAL,
237 		.address	= (struct sockaddr *)&rpcb_localaddr_rpcbind,
238 		.addrsize	= sizeof(rpcb_localaddr_rpcbind),
239 		.servername	= "localhost",
240 		.program	= &rpcb_program,
241 		.version	= RPCBVERS_2,
242 		.authflavor	= RPC_AUTH_NULL,
243 		/*
244 		 * We turn off the idle timeout to prevent the kernel
245 		 * from automatically disconnecting the socket.
246 		 * Otherwise, we'd have to cache the mount namespace
247 		 * of the caller and somehow pass that to the socket
248 		 * reconnect code.
249 		 */
250 		.flags		= RPC_CLNT_CREATE_NO_IDLE_TIMEOUT,
251 	};
252 	struct rpc_clnt *clnt, *clnt4;
253 	int result = 0;
254 
255 	/*
256 	 * Because we requested an RPC PING at transport creation time,
257 	 * this works only if the user space portmapper is rpcbind, and
258 	 * it's listening on AF_LOCAL on the named socket.
259 	 */
260 	clnt = rpc_create(&args);
261 	if (IS_ERR(clnt)) {
262 		dprintk("RPC:       failed to create AF_LOCAL rpcbind "
263 				"client (errno %ld).\n", PTR_ERR(clnt));
264 		result = PTR_ERR(clnt);
265 		goto out;
266 	}
267 
268 	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
269 	if (IS_ERR(clnt4)) {
270 		dprintk("RPC:       failed to bind second program to "
271 				"rpcbind v4 client (errno %ld).\n",
272 				PTR_ERR(clnt4));
273 		clnt4 = NULL;
274 	}
275 
276 	rpcb_set_local(net, clnt, clnt4, true);
277 
278 out:
279 	return result;
280 }
281 
282 /*
283  * Returns zero on success, otherwise a negative errno value
284  * is returned.
285  */
286 static int rpcb_create_local_net(struct net *net)
287 {
288 	static const struct sockaddr_in rpcb_inaddr_loopback = {
289 		.sin_family		= AF_INET,
290 		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
291 		.sin_port		= htons(RPCBIND_PORT),
292 	};
293 	struct rpc_create_args args = {
294 		.net		= net,
295 		.protocol	= XPRT_TRANSPORT_TCP,
296 		.address	= (struct sockaddr *)&rpcb_inaddr_loopback,
297 		.addrsize	= sizeof(rpcb_inaddr_loopback),
298 		.servername	= "localhost",
299 		.program	= &rpcb_program,
300 		.version	= RPCBVERS_2,
301 		.authflavor	= RPC_AUTH_UNIX,
302 		.flags		= RPC_CLNT_CREATE_NOPING,
303 	};
304 	struct rpc_clnt *clnt, *clnt4;
305 	int result = 0;
306 
307 	clnt = rpc_create(&args);
308 	if (IS_ERR(clnt)) {
309 		dprintk("RPC:       failed to create local rpcbind "
310 				"client (errno %ld).\n", PTR_ERR(clnt));
311 		result = PTR_ERR(clnt);
312 		goto out;
313 	}
314 
315 	/*
316 	 * This results in an RPC ping.  On systems running portmapper,
317 	 * the v4 ping will fail.  Proceed anyway, but disallow rpcb
318 	 * v4 upcalls.
319 	 */
320 	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
321 	if (IS_ERR(clnt4)) {
322 		dprintk("RPC:       failed to bind second program to "
323 				"rpcbind v4 client (errno %ld).\n",
324 				PTR_ERR(clnt4));
325 		clnt4 = NULL;
326 	}
327 
328 	rpcb_set_local(net, clnt, clnt4, false);
329 
330 out:
331 	return result;
332 }
333 
334 /*
335  * Returns zero on success, otherwise a negative errno value
336  * is returned.
337  */
338 int rpcb_create_local(struct net *net)
339 {
340 	static DEFINE_MUTEX(rpcb_create_local_mutex);
341 	int result = 0;
342 
343 	if (rpcb_get_local(net))
344 		return result;
345 
346 	mutex_lock(&rpcb_create_local_mutex);
347 	if (rpcb_get_local(net))
348 		goto out;
349 
350 	if (rpcb_create_local_unix(net) != 0)
351 		result = rpcb_create_local_net(net);
352 
353 out:
354 	mutex_unlock(&rpcb_create_local_mutex);
355 	return result;
356 }
357 
358 static struct rpc_clnt *rpcb_create(struct net *net, const char *nodename,
359 				    const char *hostname,
360 				    struct sockaddr *srvaddr, size_t salen,
361 				    int proto, u32 version)
362 {
363 	struct rpc_create_args args = {
364 		.net		= net,
365 		.protocol	= proto,
366 		.address	= srvaddr,
367 		.addrsize	= salen,
368 		.servername	= hostname,
369 		.nodename	= nodename,
370 		.program	= &rpcb_program,
371 		.version	= version,
372 		.authflavor	= RPC_AUTH_UNIX,
373 		.flags		= (RPC_CLNT_CREATE_NOPING |
374 					RPC_CLNT_CREATE_NONPRIVPORT),
375 	};
376 
377 	switch (srvaddr->sa_family) {
378 	case AF_INET:
379 		((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
380 		break;
381 	case AF_INET6:
382 		((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
383 		break;
384 	default:
385 		return ERR_PTR(-EAFNOSUPPORT);
386 	}
387 
388 	return rpc_create(&args);
389 }
390 
391 static int rpcb_register_call(struct sunrpc_net *sn, struct rpc_clnt *clnt, struct rpc_message *msg, bool is_set)
392 {
393 	int flags = RPC_TASK_NOCONNECT;
394 	int error, result = 0;
395 
396 	if (is_set || !sn->rpcb_is_af_local)
397 		flags = RPC_TASK_SOFTCONN;
398 	msg->rpc_resp = &result;
399 
400 	error = rpc_call_sync(clnt, msg, flags);
401 	if (error < 0) {
402 		dprintk("RPC:       failed to contact local rpcbind "
403 				"server (errno %d).\n", -error);
404 		return error;
405 	}
406 
407 	if (!result)
408 		return -EACCES;
409 	return 0;
410 }
411 
412 /**
413  * rpcb_register - set or unset a port registration with the local rpcbind svc
414  * @net: target network namespace
415  * @prog: RPC program number to bind
416  * @vers: RPC version number to bind
417  * @prot: transport protocol to register
418  * @port: port value to register
419  *
420  * Returns zero if the registration request was dispatched successfully
421  * and the rpcbind daemon returned success.  Otherwise, returns an errno
422  * value that reflects the nature of the error (request could not be
423  * dispatched, timed out, or rpcbind returned an error).
424  *
425  * RPC services invoke this function to advertise their contact
426  * information via the system's rpcbind daemon.  RPC services
427  * invoke this function once for each [program, version, transport]
428  * tuple they wish to advertise.
429  *
430  * Callers may also unregister RPC services that are no longer
431  * available by setting the passed-in port to zero.  This removes
432  * all registered transports for [program, version] from the local
433  * rpcbind database.
434  *
435  * This function uses rpcbind protocol version 2 to contact the
436  * local rpcbind daemon.
437  *
438  * Registration works over both AF_INET and AF_INET6, and services
439  * registered via this function are advertised as available for any
440  * address.  If the local rpcbind daemon is listening on AF_INET6,
441  * services registered via this function will be advertised on
442  * IN6ADDR_ANY (ie available for all AF_INET and AF_INET6
443  * addresses).
444  */
445 int rpcb_register(struct net *net, u32 prog, u32 vers, int prot, unsigned short port)
446 {
447 	struct rpcbind_args map = {
448 		.r_prog		= prog,
449 		.r_vers		= vers,
450 		.r_prot		= prot,
451 		.r_port		= port,
452 	};
453 	struct rpc_message msg = {
454 		.rpc_argp	= &map,
455 	};
456 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
457 	bool is_set = false;
458 
459 	dprintk("RPC:       %sregistering (%u, %u, %d, %u) with local "
460 			"rpcbind\n", (port ? "" : "un"),
461 			prog, vers, prot, port);
462 
463 	msg.rpc_proc = &rpcb_procedures2[RPCBPROC_UNSET];
464 	if (port != 0) {
465 		msg.rpc_proc = &rpcb_procedures2[RPCBPROC_SET];
466 		is_set = true;
467 	}
468 
469 	return rpcb_register_call(sn, sn->rpcb_local_clnt, &msg, is_set);
470 }
471 
472 /*
473  * Fill in AF_INET family-specific arguments to register
474  */
475 static int rpcb_register_inet4(struct sunrpc_net *sn,
476 			       const struct sockaddr *sap,
477 			       struct rpc_message *msg)
478 {
479 	const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
480 	struct rpcbind_args *map = msg->rpc_argp;
481 	unsigned short port = ntohs(sin->sin_port);
482 	bool is_set = false;
483 	int result;
484 
485 	map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
486 
487 	dprintk("RPC:       %sregistering [%u, %u, %s, '%s'] with "
488 		"local rpcbind\n", (port ? "" : "un"),
489 			map->r_prog, map->r_vers,
490 			map->r_addr, map->r_netid);
491 
492 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
493 	if (port != 0) {
494 		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
495 		is_set = true;
496 	}
497 
498 	result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
499 	kfree(map->r_addr);
500 	return result;
501 }
502 
503 /*
504  * Fill in AF_INET6 family-specific arguments to register
505  */
506 static int rpcb_register_inet6(struct sunrpc_net *sn,
507 			       const struct sockaddr *sap,
508 			       struct rpc_message *msg)
509 {
510 	const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)sap;
511 	struct rpcbind_args *map = msg->rpc_argp;
512 	unsigned short port = ntohs(sin6->sin6_port);
513 	bool is_set = false;
514 	int result;
515 
516 	map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
517 
518 	dprintk("RPC:       %sregistering [%u, %u, %s, '%s'] with "
519 		"local rpcbind\n", (port ? "" : "un"),
520 			map->r_prog, map->r_vers,
521 			map->r_addr, map->r_netid);
522 
523 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
524 	if (port != 0) {
525 		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
526 		is_set = true;
527 	}
528 
529 	result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
530 	kfree(map->r_addr);
531 	return result;
532 }
533 
534 static int rpcb_unregister_all_protofamilies(struct sunrpc_net *sn,
535 					     struct rpc_message *msg)
536 {
537 	struct rpcbind_args *map = msg->rpc_argp;
538 
539 	dprintk("RPC:       unregistering [%u, %u, '%s'] with "
540 		"local rpcbind\n",
541 			map->r_prog, map->r_vers, map->r_netid);
542 
543 	map->r_addr = "";
544 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
545 
546 	return rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, false);
547 }
548 
549 /**
550  * rpcb_v4_register - set or unset a port registration with the local rpcbind
551  * @net: target network namespace
552  * @program: RPC program number of service to (un)register
553  * @version: RPC version number of service to (un)register
554  * @address: address family, IP address, and port to (un)register
555  * @netid: netid of transport protocol to (un)register
556  *
557  * Returns zero if the registration request was dispatched successfully
558  * and the rpcbind daemon returned success.  Otherwise, returns an errno
559  * value that reflects the nature of the error (request could not be
560  * dispatched, timed out, or rpcbind returned an error).
561  *
562  * RPC services invoke this function to advertise their contact
563  * information via the system's rpcbind daemon.  RPC services
564  * invoke this function once for each [program, version, address,
565  * netid] tuple they wish to advertise.
566  *
567  * Callers may also unregister RPC services that are registered at a
568  * specific address by setting the port number in @address to zero.
569  * They may unregister all registered protocol families at once for
570  * a service by passing a NULL @address argument.  If @netid is ""
571  * then all netids for [program, version, address] are unregistered.
572  *
573  * This function uses rpcbind protocol version 4 to contact the
574  * local rpcbind daemon.  The local rpcbind daemon must support
575  * version 4 of the rpcbind protocol in order for these functions
576  * to register a service successfully.
577  *
578  * Supported netids include "udp" and "tcp" for UDP and TCP over
579  * IPv4, and "udp6" and "tcp6" for UDP and TCP over IPv6,
580  * respectively.
581  *
582  * The contents of @address determine the address family and the
583  * port to be registered.  The usual practice is to pass INADDR_ANY
584  * as the raw address, but specifying a non-zero address is also
585  * supported by this API if the caller wishes to advertise an RPC
586  * service on a specific network interface.
587  *
588  * Note that passing in INADDR_ANY does not create the same service
589  * registration as IN6ADDR_ANY.  The former advertises an RPC
590  * service on any IPv4 address, but not on IPv6.  The latter
591  * advertises the service on all IPv4 and IPv6 addresses.
592  */
593 int rpcb_v4_register(struct net *net, const u32 program, const u32 version,
594 		     const struct sockaddr *address, const char *netid)
595 {
596 	struct rpcbind_args map = {
597 		.r_prog		= program,
598 		.r_vers		= version,
599 		.r_netid	= netid,
600 		.r_owner	= RPCB_OWNER_STRING,
601 	};
602 	struct rpc_message msg = {
603 		.rpc_argp	= &map,
604 	};
605 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
606 
607 	if (sn->rpcb_local_clnt4 == NULL)
608 		return -EPROTONOSUPPORT;
609 
610 	if (address == NULL)
611 		return rpcb_unregister_all_protofamilies(sn, &msg);
612 
613 	switch (address->sa_family) {
614 	case AF_INET:
615 		return rpcb_register_inet4(sn, address, &msg);
616 	case AF_INET6:
617 		return rpcb_register_inet6(sn, address, &msg);
618 	}
619 
620 	return -EAFNOSUPPORT;
621 }
622 
623 static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt, struct rpcbind_args *map, struct rpc_procinfo *proc)
624 {
625 	struct rpc_message msg = {
626 		.rpc_proc = proc,
627 		.rpc_argp = map,
628 		.rpc_resp = map,
629 	};
630 	struct rpc_task_setup task_setup_data = {
631 		.rpc_client = rpcb_clnt,
632 		.rpc_message = &msg,
633 		.callback_ops = &rpcb_getport_ops,
634 		.callback_data = map,
635 		.flags = RPC_TASK_ASYNC | RPC_TASK_SOFTCONN,
636 	};
637 
638 	return rpc_run_task(&task_setup_data);
639 }
640 
641 /*
642  * In the case where rpc clients have been cloned, we want to make
643  * sure that we use the program number/version etc of the actual
644  * owner of the xprt. To do so, we walk back up the tree of parents
645  * to find whoever created the transport and/or whoever has the
646  * autobind flag set.
647  */
648 static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
649 {
650 	struct rpc_clnt *parent = clnt->cl_parent;
651 	struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
652 
653 	while (parent != clnt) {
654 		if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
655 			break;
656 		if (clnt->cl_autobind)
657 			break;
658 		clnt = parent;
659 		parent = parent->cl_parent;
660 	}
661 	return clnt;
662 }
663 
664 /**
665  * rpcb_getport_async - obtain the port for a given RPC service on a given host
666  * @task: task that is waiting for portmapper request
667  *
668  * This one can be called for an ongoing RPC request, and can be used in
669  * an async (rpciod) context.
670  */
671 void rpcb_getport_async(struct rpc_task *task)
672 {
673 	struct rpc_clnt *clnt;
674 	struct rpc_procinfo *proc;
675 	u32 bind_version;
676 	struct rpc_xprt *xprt;
677 	struct rpc_clnt	*rpcb_clnt;
678 	struct rpcbind_args *map;
679 	struct rpc_task	*child;
680 	struct sockaddr_storage addr;
681 	struct sockaddr *sap = (struct sockaddr *)&addr;
682 	size_t salen;
683 	int status;
684 
685 	rcu_read_lock();
686 	clnt = rpcb_find_transport_owner(task->tk_client);
687 	rcu_read_unlock();
688 	xprt = xprt_get(task->tk_xprt);
689 
690 	dprintk("RPC: %5u %s(%s, %u, %u, %d)\n",
691 		task->tk_pid, __func__,
692 		xprt->servername, clnt->cl_prog, clnt->cl_vers, xprt->prot);
693 
694 	/* Put self on the wait queue to ensure we get notified if
695 	 * some other task is already attempting to bind the port */
696 	rpc_sleep_on(&xprt->binding, task, NULL);
697 
698 	if (xprt_test_and_set_binding(xprt)) {
699 		dprintk("RPC: %5u %s: waiting for another binder\n",
700 			task->tk_pid, __func__);
701 		xprt_put(xprt);
702 		return;
703 	}
704 
705 	/* Someone else may have bound if we slept */
706 	if (xprt_bound(xprt)) {
707 		status = 0;
708 		dprintk("RPC: %5u %s: already bound\n",
709 			task->tk_pid, __func__);
710 		goto bailout_nofree;
711 	}
712 
713 	/* Parent transport's destination address */
714 	salen = rpc_peeraddr(clnt, sap, sizeof(addr));
715 
716 	/* Don't ever use rpcbind v2 for AF_INET6 requests */
717 	switch (sap->sa_family) {
718 	case AF_INET:
719 		proc = rpcb_next_version[xprt->bind_index].rpc_proc;
720 		bind_version = rpcb_next_version[xprt->bind_index].rpc_vers;
721 		break;
722 	case AF_INET6:
723 		proc = rpcb_next_version6[xprt->bind_index].rpc_proc;
724 		bind_version = rpcb_next_version6[xprt->bind_index].rpc_vers;
725 		break;
726 	default:
727 		status = -EAFNOSUPPORT;
728 		dprintk("RPC: %5u %s: bad address family\n",
729 				task->tk_pid, __func__);
730 		goto bailout_nofree;
731 	}
732 	if (proc == NULL) {
733 		xprt->bind_index = 0;
734 		status = -EPFNOSUPPORT;
735 		dprintk("RPC: %5u %s: no more getport versions available\n",
736 			task->tk_pid, __func__);
737 		goto bailout_nofree;
738 	}
739 
740 	dprintk("RPC: %5u %s: trying rpcbind version %u\n",
741 		task->tk_pid, __func__, bind_version);
742 
743 	rpcb_clnt = rpcb_create(xprt->xprt_net,
744 				clnt->cl_nodename,
745 				xprt->servername, sap, salen,
746 				xprt->prot, bind_version);
747 	if (IS_ERR(rpcb_clnt)) {
748 		status = PTR_ERR(rpcb_clnt);
749 		dprintk("RPC: %5u %s: rpcb_create failed, error %ld\n",
750 			task->tk_pid, __func__, PTR_ERR(rpcb_clnt));
751 		goto bailout_nofree;
752 	}
753 
754 	map = kzalloc(sizeof(struct rpcbind_args), GFP_ATOMIC);
755 	if (!map) {
756 		status = -ENOMEM;
757 		dprintk("RPC: %5u %s: no memory available\n",
758 			task->tk_pid, __func__);
759 		goto bailout_release_client;
760 	}
761 	map->r_prog = clnt->cl_prog;
762 	map->r_vers = clnt->cl_vers;
763 	map->r_prot = xprt->prot;
764 	map->r_port = 0;
765 	map->r_xprt = xprt;
766 	map->r_status = -EIO;
767 
768 	switch (bind_version) {
769 	case RPCBVERS_4:
770 	case RPCBVERS_3:
771 		map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
772 		map->r_addr = rpc_sockaddr2uaddr(sap, GFP_ATOMIC);
773 		map->r_owner = "";
774 		break;
775 	case RPCBVERS_2:
776 		map->r_addr = NULL;
777 		break;
778 	default:
779 		BUG();
780 	}
781 
782 	child = rpcb_call_async(rpcb_clnt, map, proc);
783 	rpc_release_client(rpcb_clnt);
784 	if (IS_ERR(child)) {
785 		/* rpcb_map_release() has freed the arguments */
786 		dprintk("RPC: %5u %s: rpc_run_task failed\n",
787 			task->tk_pid, __func__);
788 		return;
789 	}
790 
791 	xprt->stat.bind_count++;
792 	rpc_put_task(child);
793 	return;
794 
795 bailout_release_client:
796 	rpc_release_client(rpcb_clnt);
797 bailout_nofree:
798 	rpcb_wake_rpcbind_waiters(xprt, status);
799 	task->tk_status = status;
800 	xprt_put(xprt);
801 }
802 EXPORT_SYMBOL_GPL(rpcb_getport_async);
803 
804 /*
805  * Rpcbind child task calls this callback via tk_exit.
806  */
807 static void rpcb_getport_done(struct rpc_task *child, void *data)
808 {
809 	struct rpcbind_args *map = data;
810 	struct rpc_xprt *xprt = map->r_xprt;
811 	int status = child->tk_status;
812 
813 	/* Garbage reply: retry with a lesser rpcbind version */
814 	if (status == -EIO)
815 		status = -EPROTONOSUPPORT;
816 
817 	/* rpcbind server doesn't support this rpcbind protocol version */
818 	if (status == -EPROTONOSUPPORT)
819 		xprt->bind_index++;
820 
821 	if (status < 0) {
822 		/* rpcbind server not available on remote host? */
823 		xprt->ops->set_port(xprt, 0);
824 	} else if (map->r_port == 0) {
825 		/* Requested RPC service wasn't registered on remote host */
826 		xprt->ops->set_port(xprt, 0);
827 		status = -EACCES;
828 	} else {
829 		/* Succeeded */
830 		xprt->ops->set_port(xprt, map->r_port);
831 		xprt_set_bound(xprt);
832 		status = 0;
833 	}
834 
835 	dprintk("RPC: %5u rpcb_getport_done(status %d, port %u)\n",
836 			child->tk_pid, status, map->r_port);
837 
838 	map->r_status = status;
839 }
840 
841 /*
842  * XDR functions for rpcbind
843  */
844 
845 static void rpcb_enc_mapping(struct rpc_rqst *req, struct xdr_stream *xdr,
846 			     const struct rpcbind_args *rpcb)
847 {
848 	__be32 *p;
849 
850 	dprintk("RPC: %5u encoding PMAP_%s call (%u, %u, %d, %u)\n",
851 			req->rq_task->tk_pid,
852 			req->rq_task->tk_msg.rpc_proc->p_name,
853 			rpcb->r_prog, rpcb->r_vers, rpcb->r_prot, rpcb->r_port);
854 
855 	p = xdr_reserve_space(xdr, RPCB_mappingargs_sz << 2);
856 	*p++ = cpu_to_be32(rpcb->r_prog);
857 	*p++ = cpu_to_be32(rpcb->r_vers);
858 	*p++ = cpu_to_be32(rpcb->r_prot);
859 	*p   = cpu_to_be32(rpcb->r_port);
860 }
861 
862 static int rpcb_dec_getport(struct rpc_rqst *req, struct xdr_stream *xdr,
863 			    struct rpcbind_args *rpcb)
864 {
865 	unsigned long port;
866 	__be32 *p;
867 
868 	rpcb->r_port = 0;
869 
870 	p = xdr_inline_decode(xdr, 4);
871 	if (unlikely(p == NULL))
872 		return -EIO;
873 
874 	port = be32_to_cpup(p);
875 	dprintk("RPC: %5u PMAP_%s result: %lu\n", req->rq_task->tk_pid,
876 			req->rq_task->tk_msg.rpc_proc->p_name, port);
877 	if (unlikely(port > USHRT_MAX))
878 		return -EIO;
879 
880 	rpcb->r_port = port;
881 	return 0;
882 }
883 
884 static int rpcb_dec_set(struct rpc_rqst *req, struct xdr_stream *xdr,
885 			unsigned int *boolp)
886 {
887 	__be32 *p;
888 
889 	p = xdr_inline_decode(xdr, 4);
890 	if (unlikely(p == NULL))
891 		return -EIO;
892 
893 	*boolp = 0;
894 	if (*p != xdr_zero)
895 		*boolp = 1;
896 
897 	dprintk("RPC: %5u RPCB_%s call %s\n",
898 			req->rq_task->tk_pid,
899 			req->rq_task->tk_msg.rpc_proc->p_name,
900 			(*boolp ? "succeeded" : "failed"));
901 	return 0;
902 }
903 
904 static void encode_rpcb_string(struct xdr_stream *xdr, const char *string,
905 			       const u32 maxstrlen)
906 {
907 	__be32 *p;
908 	u32 len;
909 
910 	len = strlen(string);
911 	WARN_ON_ONCE(len > maxstrlen);
912 	if (len > maxstrlen)
913 		/* truncate and hope for the best */
914 		len = maxstrlen;
915 	p = xdr_reserve_space(xdr, 4 + len);
916 	xdr_encode_opaque(p, string, len);
917 }
918 
919 static void rpcb_enc_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
920 			     const struct rpcbind_args *rpcb)
921 {
922 	__be32 *p;
923 
924 	dprintk("RPC: %5u encoding RPCB_%s call (%u, %u, '%s', '%s')\n",
925 			req->rq_task->tk_pid,
926 			req->rq_task->tk_msg.rpc_proc->p_name,
927 			rpcb->r_prog, rpcb->r_vers,
928 			rpcb->r_netid, rpcb->r_addr);
929 
930 	p = xdr_reserve_space(xdr, (RPCB_program_sz + RPCB_version_sz) << 2);
931 	*p++ = cpu_to_be32(rpcb->r_prog);
932 	*p = cpu_to_be32(rpcb->r_vers);
933 
934 	encode_rpcb_string(xdr, rpcb->r_netid, RPCBIND_MAXNETIDLEN);
935 	encode_rpcb_string(xdr, rpcb->r_addr, RPCBIND_MAXUADDRLEN);
936 	encode_rpcb_string(xdr, rpcb->r_owner, RPCB_MAXOWNERLEN);
937 }
938 
939 static int rpcb_dec_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
940 			    struct rpcbind_args *rpcb)
941 {
942 	struct sockaddr_storage address;
943 	struct sockaddr *sap = (struct sockaddr *)&address;
944 	__be32 *p;
945 	u32 len;
946 
947 	rpcb->r_port = 0;
948 
949 	p = xdr_inline_decode(xdr, 4);
950 	if (unlikely(p == NULL))
951 		goto out_fail;
952 	len = be32_to_cpup(p);
953 
954 	/*
955 	 * If the returned universal address is a null string,
956 	 * the requested RPC service was not registered.
957 	 */
958 	if (len == 0) {
959 		dprintk("RPC: %5u RPCB reply: program not registered\n",
960 				req->rq_task->tk_pid);
961 		return 0;
962 	}
963 
964 	if (unlikely(len > RPCBIND_MAXUADDRLEN))
965 		goto out_fail;
966 
967 	p = xdr_inline_decode(xdr, len);
968 	if (unlikely(p == NULL))
969 		goto out_fail;
970 	dprintk("RPC: %5u RPCB_%s reply: %s\n", req->rq_task->tk_pid,
971 			req->rq_task->tk_msg.rpc_proc->p_name, (char *)p);
972 
973 	if (rpc_uaddr2sockaddr(req->rq_xprt->xprt_net, (char *)p, len,
974 				sap, sizeof(address)) == 0)
975 		goto out_fail;
976 	rpcb->r_port = rpc_get_port(sap);
977 
978 	return 0;
979 
980 out_fail:
981 	dprintk("RPC: %5u malformed RPCB_%s reply\n",
982 			req->rq_task->tk_pid,
983 			req->rq_task->tk_msg.rpc_proc->p_name);
984 	return -EIO;
985 }
986 
987 /*
988  * Not all rpcbind procedures described in RFC 1833 are implemented
989  * since the Linux kernel RPC code requires only these.
990  */
991 
992 static struct rpc_procinfo rpcb_procedures2[] = {
993 	[RPCBPROC_SET] = {
994 		.p_proc		= RPCBPROC_SET,
995 		.p_encode	= (kxdreproc_t)rpcb_enc_mapping,
996 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
997 		.p_arglen	= RPCB_mappingargs_sz,
998 		.p_replen	= RPCB_setres_sz,
999 		.p_statidx	= RPCBPROC_SET,
1000 		.p_timer	= 0,
1001 		.p_name		= "SET",
1002 	},
1003 	[RPCBPROC_UNSET] = {
1004 		.p_proc		= RPCBPROC_UNSET,
1005 		.p_encode	= (kxdreproc_t)rpcb_enc_mapping,
1006 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
1007 		.p_arglen	= RPCB_mappingargs_sz,
1008 		.p_replen	= RPCB_setres_sz,
1009 		.p_statidx	= RPCBPROC_UNSET,
1010 		.p_timer	= 0,
1011 		.p_name		= "UNSET",
1012 	},
1013 	[RPCBPROC_GETPORT] = {
1014 		.p_proc		= RPCBPROC_GETPORT,
1015 		.p_encode	= (kxdreproc_t)rpcb_enc_mapping,
1016 		.p_decode	= (kxdrdproc_t)rpcb_dec_getport,
1017 		.p_arglen	= RPCB_mappingargs_sz,
1018 		.p_replen	= RPCB_getportres_sz,
1019 		.p_statidx	= RPCBPROC_GETPORT,
1020 		.p_timer	= 0,
1021 		.p_name		= "GETPORT",
1022 	},
1023 };
1024 
1025 static struct rpc_procinfo rpcb_procedures3[] = {
1026 	[RPCBPROC_SET] = {
1027 		.p_proc		= RPCBPROC_SET,
1028 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1029 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
1030 		.p_arglen	= RPCB_getaddrargs_sz,
1031 		.p_replen	= RPCB_setres_sz,
1032 		.p_statidx	= RPCBPROC_SET,
1033 		.p_timer	= 0,
1034 		.p_name		= "SET",
1035 	},
1036 	[RPCBPROC_UNSET] = {
1037 		.p_proc		= RPCBPROC_UNSET,
1038 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1039 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
1040 		.p_arglen	= RPCB_getaddrargs_sz,
1041 		.p_replen	= RPCB_setres_sz,
1042 		.p_statidx	= RPCBPROC_UNSET,
1043 		.p_timer	= 0,
1044 		.p_name		= "UNSET",
1045 	},
1046 	[RPCBPROC_GETADDR] = {
1047 		.p_proc		= RPCBPROC_GETADDR,
1048 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1049 		.p_decode	= (kxdrdproc_t)rpcb_dec_getaddr,
1050 		.p_arglen	= RPCB_getaddrargs_sz,
1051 		.p_replen	= RPCB_getaddrres_sz,
1052 		.p_statidx	= RPCBPROC_GETADDR,
1053 		.p_timer	= 0,
1054 		.p_name		= "GETADDR",
1055 	},
1056 };
1057 
1058 static struct rpc_procinfo rpcb_procedures4[] = {
1059 	[RPCBPROC_SET] = {
1060 		.p_proc		= RPCBPROC_SET,
1061 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1062 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
1063 		.p_arglen	= RPCB_getaddrargs_sz,
1064 		.p_replen	= RPCB_setres_sz,
1065 		.p_statidx	= RPCBPROC_SET,
1066 		.p_timer	= 0,
1067 		.p_name		= "SET",
1068 	},
1069 	[RPCBPROC_UNSET] = {
1070 		.p_proc		= RPCBPROC_UNSET,
1071 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1072 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
1073 		.p_arglen	= RPCB_getaddrargs_sz,
1074 		.p_replen	= RPCB_setres_sz,
1075 		.p_statidx	= RPCBPROC_UNSET,
1076 		.p_timer	= 0,
1077 		.p_name		= "UNSET",
1078 	},
1079 	[RPCBPROC_GETADDR] = {
1080 		.p_proc		= RPCBPROC_GETADDR,
1081 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1082 		.p_decode	= (kxdrdproc_t)rpcb_dec_getaddr,
1083 		.p_arglen	= RPCB_getaddrargs_sz,
1084 		.p_replen	= RPCB_getaddrres_sz,
1085 		.p_statidx	= RPCBPROC_GETADDR,
1086 		.p_timer	= 0,
1087 		.p_name		= "GETADDR",
1088 	},
1089 };
1090 
1091 static const struct rpcb_info rpcb_next_version[] = {
1092 	{
1093 		.rpc_vers	= RPCBVERS_2,
1094 		.rpc_proc	= &rpcb_procedures2[RPCBPROC_GETPORT],
1095 	},
1096 	{
1097 		.rpc_proc	= NULL,
1098 	},
1099 };
1100 
1101 static const struct rpcb_info rpcb_next_version6[] = {
1102 	{
1103 		.rpc_vers	= RPCBVERS_4,
1104 		.rpc_proc	= &rpcb_procedures4[RPCBPROC_GETADDR],
1105 	},
1106 	{
1107 		.rpc_vers	= RPCBVERS_3,
1108 		.rpc_proc	= &rpcb_procedures3[RPCBPROC_GETADDR],
1109 	},
1110 	{
1111 		.rpc_proc	= NULL,
1112 	},
1113 };
1114 
1115 static const struct rpc_version rpcb_version2 = {
1116 	.number		= RPCBVERS_2,
1117 	.nrprocs	= ARRAY_SIZE(rpcb_procedures2),
1118 	.procs		= rpcb_procedures2
1119 };
1120 
1121 static const struct rpc_version rpcb_version3 = {
1122 	.number		= RPCBVERS_3,
1123 	.nrprocs	= ARRAY_SIZE(rpcb_procedures3),
1124 	.procs		= rpcb_procedures3
1125 };
1126 
1127 static const struct rpc_version rpcb_version4 = {
1128 	.number		= RPCBVERS_4,
1129 	.nrprocs	= ARRAY_SIZE(rpcb_procedures4),
1130 	.procs		= rpcb_procedures4
1131 };
1132 
1133 static const struct rpc_version *rpcb_version[] = {
1134 	NULL,
1135 	NULL,
1136 	&rpcb_version2,
1137 	&rpcb_version3,
1138 	&rpcb_version4
1139 };
1140 
1141 static struct rpc_stat rpcb_stats;
1142 
1143 static const struct rpc_program rpcb_program = {
1144 	.name		= "rpcbind",
1145 	.number		= RPCBIND_PROGRAM,
1146 	.nrvers		= ARRAY_SIZE(rpcb_version),
1147 	.version	= rpcb_version,
1148 	.stats		= &rpcb_stats,
1149 };
1150