xref: /openbmc/linux/net/sunrpc/rpcb_clnt.c (revision 6eac7d3f45a2519283d38bf670cb6968230124f8)
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 <linux/nsproxy.h>
27 #include <net/ipv6.h>
28 
29 #include <linux/sunrpc/clnt.h>
30 #include <linux/sunrpc/sched.h>
31 #include <linux/sunrpc/xprtsock.h>
32 
33 #include "netns.h"
34 
35 #ifdef RPC_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 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 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 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;
184 
185 	spin_lock(&sn->rpcb_clnt_lock);
186 	if (--sn->rpcb_users == 0) {
187 		sn->rpcb_local_clnt = NULL;
188 		sn->rpcb_local_clnt4 = NULL;
189 	}
190 	shutdown = !sn->rpcb_users;
191 	spin_unlock(&sn->rpcb_clnt_lock);
192 
193 	if (shutdown) {
194 		/*
195 		 * cleanup_rpcb_clnt - remove xprtsock's sysctls, unregister
196 		 */
197 		if (clnt4)
198 			rpc_shutdown_client(clnt4);
199 		if (clnt)
200 			rpc_shutdown_client(clnt);
201 	}
202 }
203 
204 static void rpcb_set_local(struct net *net, struct rpc_clnt *clnt,
205 			struct rpc_clnt *clnt4)
206 {
207 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
208 
209 	/* Protected by rpcb_create_local_mutex */
210 	sn->rpcb_local_clnt = clnt;
211 	sn->rpcb_local_clnt4 = clnt4;
212 	smp_wmb();
213 	sn->rpcb_users = 1;
214 	dprintk("RPC:       created new rpcb local clients (rpcb_local_clnt: "
215 			"%p, rpcb_local_clnt4: %p) for net %p%s\n",
216 			sn->rpcb_local_clnt, sn->rpcb_local_clnt4,
217 			net, (net == &init_net) ? " (init_net)" : "");
218 }
219 
220 /*
221  * Returns zero on success, otherwise a negative errno value
222  * is returned.
223  */
224 static int rpcb_create_local_unix(struct net *net)
225 {
226 	static const struct sockaddr_un rpcb_localaddr_rpcbind = {
227 		.sun_family		= AF_LOCAL,
228 		.sun_path		= RPCBIND_SOCK_PATHNAME,
229 	};
230 	struct rpc_create_args args = {
231 		.net		= net,
232 		.protocol	= XPRT_TRANSPORT_LOCAL,
233 		.address	= (struct sockaddr *)&rpcb_localaddr_rpcbind,
234 		.addrsize	= sizeof(rpcb_localaddr_rpcbind),
235 		.servername	= "localhost",
236 		.program	= &rpcb_program,
237 		.version	= RPCBVERS_2,
238 		.authflavor	= RPC_AUTH_NULL,
239 	};
240 	struct rpc_clnt *clnt, *clnt4;
241 	int result = 0;
242 
243 	/*
244 	 * Because we requested an RPC PING at transport creation time,
245 	 * this works only if the user space portmapper is rpcbind, and
246 	 * it's listening on AF_LOCAL on the named socket.
247 	 */
248 	clnt = rpc_create(&args);
249 	if (IS_ERR(clnt)) {
250 		dprintk("RPC:       failed to create AF_LOCAL rpcbind "
251 				"client (errno %ld).\n", PTR_ERR(clnt));
252 		result = -PTR_ERR(clnt);
253 		goto out;
254 	}
255 
256 	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
257 	if (IS_ERR(clnt4)) {
258 		dprintk("RPC:       failed to bind second program to "
259 				"rpcbind v4 client (errno %ld).\n",
260 				PTR_ERR(clnt4));
261 		clnt4 = NULL;
262 	}
263 
264 	rpcb_set_local(net, clnt, 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_net(struct net *net)
275 {
276 	static const struct sockaddr_in rpcb_inaddr_loopback = {
277 		.sin_family		= AF_INET,
278 		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
279 		.sin_port		= htons(RPCBIND_PORT),
280 	};
281 	struct rpc_create_args args = {
282 		.net		= net,
283 		.protocol	= XPRT_TRANSPORT_TCP,
284 		.address	= (struct sockaddr *)&rpcb_inaddr_loopback,
285 		.addrsize	= sizeof(rpcb_inaddr_loopback),
286 		.servername	= "localhost",
287 		.program	= &rpcb_program,
288 		.version	= RPCBVERS_2,
289 		.authflavor	= RPC_AUTH_UNIX,
290 		.flags		= RPC_CLNT_CREATE_NOPING,
291 	};
292 	struct rpc_clnt *clnt, *clnt4;
293 	int result = 0;
294 
295 	clnt = rpc_create(&args);
296 	if (IS_ERR(clnt)) {
297 		dprintk("RPC:       failed to create local rpcbind "
298 				"client (errno %ld).\n", PTR_ERR(clnt));
299 		result = -PTR_ERR(clnt);
300 		goto out;
301 	}
302 
303 	/*
304 	 * This results in an RPC ping.  On systems running portmapper,
305 	 * the v4 ping will fail.  Proceed anyway, but disallow rpcb
306 	 * v4 upcalls.
307 	 */
308 	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
309 	if (IS_ERR(clnt4)) {
310 		dprintk("RPC:       failed to bind second program to "
311 				"rpcbind v4 client (errno %ld).\n",
312 				PTR_ERR(clnt4));
313 		clnt4 = NULL;
314 	}
315 
316 	rpcb_set_local(net, clnt, clnt4);
317 
318 out:
319 	return result;
320 }
321 
322 /*
323  * Returns zero on success, otherwise a negative errno value
324  * is returned.
325  */
326 int rpcb_create_local(struct net *net)
327 {
328 	static DEFINE_MUTEX(rpcb_create_local_mutex);
329 	int result = 0;
330 
331 	if (rpcb_get_local(net))
332 		return result;
333 
334 	mutex_lock(&rpcb_create_local_mutex);
335 	if (rpcb_get_local(net))
336 		goto out;
337 
338 	if (rpcb_create_local_unix(net) != 0)
339 		result = rpcb_create_local_net(net);
340 
341 out:
342 	mutex_unlock(&rpcb_create_local_mutex);
343 	return result;
344 }
345 
346 static struct rpc_clnt *rpcb_create(struct net *net, const char *hostname,
347 				    struct sockaddr *srvaddr, size_t salen,
348 				    int proto, u32 version)
349 {
350 	struct rpc_create_args args = {
351 		.net		= net,
352 		.protocol	= proto,
353 		.address	= srvaddr,
354 		.addrsize	= salen,
355 		.servername	= hostname,
356 		.program	= &rpcb_program,
357 		.version	= version,
358 		.authflavor	= RPC_AUTH_UNIX,
359 		.flags		= (RPC_CLNT_CREATE_NOPING |
360 					RPC_CLNT_CREATE_NONPRIVPORT),
361 	};
362 
363 	switch (srvaddr->sa_family) {
364 	case AF_INET:
365 		((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
366 		break;
367 	case AF_INET6:
368 		((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
369 		break;
370 	default:
371 		return ERR_PTR(-EAFNOSUPPORT);
372 	}
373 
374 	return rpc_create(&args);
375 }
376 
377 static int rpcb_register_call(struct rpc_clnt *clnt, struct rpc_message *msg)
378 {
379 	int result, error = 0;
380 
381 	msg->rpc_resp = &result;
382 
383 	error = rpc_call_sync(clnt, msg, RPC_TASK_SOFTCONN);
384 	if (error < 0) {
385 		dprintk("RPC:       failed to contact local rpcbind "
386 				"server (errno %d).\n", -error);
387 		return error;
388 	}
389 
390 	if (!result)
391 		return -EACCES;
392 	return 0;
393 }
394 
395 /**
396  * rpcb_register - set or unset a port registration with the local rpcbind svc
397  * @prog: RPC program number to bind
398  * @vers: RPC version number to bind
399  * @prot: transport protocol to register
400  * @port: port value to register
401  *
402  * Returns zero if the registration request was dispatched successfully
403  * and the rpcbind daemon returned success.  Otherwise, returns an errno
404  * value that reflects the nature of the error (request could not be
405  * dispatched, timed out, or rpcbind returned an error).
406  *
407  * RPC services invoke this function to advertise their contact
408  * information via the system's rpcbind daemon.  RPC services
409  * invoke this function once for each [program, version, transport]
410  * tuple they wish to advertise.
411  *
412  * Callers may also unregister RPC services that are no longer
413  * available by setting the passed-in port to zero.  This removes
414  * all registered transports for [program, version] from the local
415  * rpcbind database.
416  *
417  * This function uses rpcbind protocol version 2 to contact the
418  * local rpcbind daemon.
419  *
420  * Registration works over both AF_INET and AF_INET6, and services
421  * registered via this function are advertised as available for any
422  * address.  If the local rpcbind daemon is listening on AF_INET6,
423  * services registered via this function will be advertised on
424  * IN6ADDR_ANY (ie available for all AF_INET and AF_INET6
425  * addresses).
426  */
427 int rpcb_register(struct net *net, u32 prog, u32 vers, int prot, unsigned short port)
428 {
429 	struct rpcbind_args map = {
430 		.r_prog		= prog,
431 		.r_vers		= vers,
432 		.r_prot		= prot,
433 		.r_port		= port,
434 	};
435 	struct rpc_message msg = {
436 		.rpc_argp	= &map,
437 	};
438 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
439 
440 	dprintk("RPC:       %sregistering (%u, %u, %d, %u) with local "
441 			"rpcbind\n", (port ? "" : "un"),
442 			prog, vers, prot, port);
443 
444 	msg.rpc_proc = &rpcb_procedures2[RPCBPROC_UNSET];
445 	if (port)
446 		msg.rpc_proc = &rpcb_procedures2[RPCBPROC_SET];
447 
448 	return rpcb_register_call(sn->rpcb_local_clnt, &msg);
449 }
450 
451 /*
452  * Fill in AF_INET family-specific arguments to register
453  */
454 static int rpcb_register_inet4(struct sunrpc_net *sn,
455 			       const struct sockaddr *sap,
456 			       struct rpc_message *msg)
457 {
458 	const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
459 	struct rpcbind_args *map = msg->rpc_argp;
460 	unsigned short port = ntohs(sin->sin_port);
461 	int result;
462 
463 	map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
464 
465 	dprintk("RPC:       %sregistering [%u, %u, %s, '%s'] with "
466 		"local rpcbind\n", (port ? "" : "un"),
467 			map->r_prog, map->r_vers,
468 			map->r_addr, map->r_netid);
469 
470 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
471 	if (port)
472 		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
473 
474 	result = rpcb_register_call(sn->rpcb_local_clnt4, msg);
475 	kfree(map->r_addr);
476 	return result;
477 }
478 
479 /*
480  * Fill in AF_INET6 family-specific arguments to register
481  */
482 static int rpcb_register_inet6(struct sunrpc_net *sn,
483 			       const struct sockaddr *sap,
484 			       struct rpc_message *msg)
485 {
486 	const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)sap;
487 	struct rpcbind_args *map = msg->rpc_argp;
488 	unsigned short port = ntohs(sin6->sin6_port);
489 	int result;
490 
491 	map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
492 
493 	dprintk("RPC:       %sregistering [%u, %u, %s, '%s'] with "
494 		"local rpcbind\n", (port ? "" : "un"),
495 			map->r_prog, map->r_vers,
496 			map->r_addr, map->r_netid);
497 
498 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
499 	if (port)
500 		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
501 
502 	result = rpcb_register_call(sn->rpcb_local_clnt4, msg);
503 	kfree(map->r_addr);
504 	return result;
505 }
506 
507 static int rpcb_unregister_all_protofamilies(struct sunrpc_net *sn,
508 					     struct rpc_message *msg)
509 {
510 	struct rpcbind_args *map = msg->rpc_argp;
511 
512 	dprintk("RPC:       unregistering [%u, %u, '%s'] with "
513 		"local rpcbind\n",
514 			map->r_prog, map->r_vers, map->r_netid);
515 
516 	map->r_addr = "";
517 	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
518 
519 	return rpcb_register_call(sn->rpcb_local_clnt4, msg);
520 }
521 
522 /**
523  * rpcb_v4_register - set or unset a port registration with the local rpcbind
524  * @program: RPC program number of service to (un)register
525  * @version: RPC version number of service to (un)register
526  * @address: address family, IP address, and port to (un)register
527  * @netid: netid of transport protocol to (un)register
528  *
529  * Returns zero if the registration request was dispatched successfully
530  * and the rpcbind daemon returned success.  Otherwise, returns an errno
531  * value that reflects the nature of the error (request could not be
532  * dispatched, timed out, or rpcbind returned an error).
533  *
534  * RPC services invoke this function to advertise their contact
535  * information via the system's rpcbind daemon.  RPC services
536  * invoke this function once for each [program, version, address,
537  * netid] tuple they wish to advertise.
538  *
539  * Callers may also unregister RPC services that are registered at a
540  * specific address by setting the port number in @address to zero.
541  * They may unregister all registered protocol families at once for
542  * a service by passing a NULL @address argument.  If @netid is ""
543  * then all netids for [program, version, address] are unregistered.
544  *
545  * This function uses rpcbind protocol version 4 to contact the
546  * local rpcbind daemon.  The local rpcbind daemon must support
547  * version 4 of the rpcbind protocol in order for these functions
548  * to register a service successfully.
549  *
550  * Supported netids include "udp" and "tcp" for UDP and TCP over
551  * IPv4, and "udp6" and "tcp6" for UDP and TCP over IPv6,
552  * respectively.
553  *
554  * The contents of @address determine the address family and the
555  * port to be registered.  The usual practice is to pass INADDR_ANY
556  * as the raw address, but specifying a non-zero address is also
557  * supported by this API if the caller wishes to advertise an RPC
558  * service on a specific network interface.
559  *
560  * Note that passing in INADDR_ANY does not create the same service
561  * registration as IN6ADDR_ANY.  The former advertises an RPC
562  * service on any IPv4 address, but not on IPv6.  The latter
563  * advertises the service on all IPv4 and IPv6 addresses.
564  */
565 int rpcb_v4_register(struct net *net, const u32 program, const u32 version,
566 		     const struct sockaddr *address, const char *netid)
567 {
568 	struct rpcbind_args map = {
569 		.r_prog		= program,
570 		.r_vers		= version,
571 		.r_netid	= netid,
572 		.r_owner	= RPCB_OWNER_STRING,
573 	};
574 	struct rpc_message msg = {
575 		.rpc_argp	= &map,
576 	};
577 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
578 
579 	if (sn->rpcb_local_clnt4 == NULL)
580 		return -EPROTONOSUPPORT;
581 
582 	if (address == NULL)
583 		return rpcb_unregister_all_protofamilies(sn, &msg);
584 
585 	switch (address->sa_family) {
586 	case AF_INET:
587 		return rpcb_register_inet4(sn, address, &msg);
588 	case AF_INET6:
589 		return rpcb_register_inet6(sn, address, &msg);
590 	}
591 
592 	return -EAFNOSUPPORT;
593 }
594 
595 static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt, struct rpcbind_args *map, struct rpc_procinfo *proc)
596 {
597 	struct rpc_message msg = {
598 		.rpc_proc = proc,
599 		.rpc_argp = map,
600 		.rpc_resp = map,
601 	};
602 	struct rpc_task_setup task_setup_data = {
603 		.rpc_client = rpcb_clnt,
604 		.rpc_message = &msg,
605 		.callback_ops = &rpcb_getport_ops,
606 		.callback_data = map,
607 		.flags = RPC_TASK_ASYNC | RPC_TASK_SOFTCONN,
608 	};
609 
610 	return rpc_run_task(&task_setup_data);
611 }
612 
613 /*
614  * In the case where rpc clients have been cloned, we want to make
615  * sure that we use the program number/version etc of the actual
616  * owner of the xprt. To do so, we walk back up the tree of parents
617  * to find whoever created the transport and/or whoever has the
618  * autobind flag set.
619  */
620 static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
621 {
622 	struct rpc_clnt *parent = clnt->cl_parent;
623 
624 	while (parent != clnt) {
625 		if (parent->cl_xprt != clnt->cl_xprt)
626 			break;
627 		if (clnt->cl_autobind)
628 			break;
629 		clnt = parent;
630 		parent = parent->cl_parent;
631 	}
632 	return clnt;
633 }
634 
635 /**
636  * rpcb_getport_async - obtain the port for a given RPC service on a given host
637  * @task: task that is waiting for portmapper request
638  *
639  * This one can be called for an ongoing RPC request, and can be used in
640  * an async (rpciod) context.
641  */
642 void rpcb_getport_async(struct rpc_task *task)
643 {
644 	struct rpc_clnt *clnt;
645 	struct rpc_procinfo *proc;
646 	u32 bind_version;
647 	struct rpc_xprt *xprt;
648 	struct rpc_clnt	*rpcb_clnt;
649 	struct rpcbind_args *map;
650 	struct rpc_task	*child;
651 	struct sockaddr_storage addr;
652 	struct sockaddr *sap = (struct sockaddr *)&addr;
653 	size_t salen;
654 	int status;
655 
656 	clnt = rpcb_find_transport_owner(task->tk_client);
657 	xprt = clnt->cl_xprt;
658 
659 	dprintk("RPC: %5u %s(%s, %u, %u, %d)\n",
660 		task->tk_pid, __func__,
661 		clnt->cl_server, clnt->cl_prog, clnt->cl_vers, xprt->prot);
662 
663 	/* Put self on the wait queue to ensure we get notified if
664 	 * some other task is already attempting to bind the port */
665 	rpc_sleep_on(&xprt->binding, task, NULL);
666 
667 	if (xprt_test_and_set_binding(xprt)) {
668 		dprintk("RPC: %5u %s: waiting for another binder\n",
669 			task->tk_pid, __func__);
670 		return;
671 	}
672 
673 	/* Someone else may have bound if we slept */
674 	if (xprt_bound(xprt)) {
675 		status = 0;
676 		dprintk("RPC: %5u %s: already bound\n",
677 			task->tk_pid, __func__);
678 		goto bailout_nofree;
679 	}
680 
681 	/* Parent transport's destination address */
682 	salen = rpc_peeraddr(clnt, sap, sizeof(addr));
683 
684 	/* Don't ever use rpcbind v2 for AF_INET6 requests */
685 	switch (sap->sa_family) {
686 	case AF_INET:
687 		proc = rpcb_next_version[xprt->bind_index].rpc_proc;
688 		bind_version = rpcb_next_version[xprt->bind_index].rpc_vers;
689 		break;
690 	case AF_INET6:
691 		proc = rpcb_next_version6[xprt->bind_index].rpc_proc;
692 		bind_version = rpcb_next_version6[xprt->bind_index].rpc_vers;
693 		break;
694 	default:
695 		status = -EAFNOSUPPORT;
696 		dprintk("RPC: %5u %s: bad address family\n",
697 				task->tk_pid, __func__);
698 		goto bailout_nofree;
699 	}
700 	if (proc == NULL) {
701 		xprt->bind_index = 0;
702 		status = -EPFNOSUPPORT;
703 		dprintk("RPC: %5u %s: no more getport versions available\n",
704 			task->tk_pid, __func__);
705 		goto bailout_nofree;
706 	}
707 
708 	dprintk("RPC: %5u %s: trying rpcbind version %u\n",
709 		task->tk_pid, __func__, bind_version);
710 
711 	rpcb_clnt = rpcb_create(xprt->xprt_net, clnt->cl_server, sap, salen,
712 				xprt->prot, bind_version);
713 	if (IS_ERR(rpcb_clnt)) {
714 		status = PTR_ERR(rpcb_clnt);
715 		dprintk("RPC: %5u %s: rpcb_create failed, error %ld\n",
716 			task->tk_pid, __func__, PTR_ERR(rpcb_clnt));
717 		goto bailout_nofree;
718 	}
719 
720 	map = kzalloc(sizeof(struct rpcbind_args), GFP_ATOMIC);
721 	if (!map) {
722 		status = -ENOMEM;
723 		dprintk("RPC: %5u %s: no memory available\n",
724 			task->tk_pid, __func__);
725 		goto bailout_release_client;
726 	}
727 	map->r_prog = clnt->cl_prog;
728 	map->r_vers = clnt->cl_vers;
729 	map->r_prot = xprt->prot;
730 	map->r_port = 0;
731 	map->r_xprt = xprt_get(xprt);
732 	map->r_status = -EIO;
733 
734 	switch (bind_version) {
735 	case RPCBVERS_4:
736 	case RPCBVERS_3:
737 		map->r_netid = rpc_peeraddr2str(clnt, RPC_DISPLAY_NETID);
738 		map->r_addr = rpc_sockaddr2uaddr(sap, GFP_ATOMIC);
739 		map->r_owner = "";
740 		break;
741 	case RPCBVERS_2:
742 		map->r_addr = NULL;
743 		break;
744 	default:
745 		BUG();
746 	}
747 
748 	child = rpcb_call_async(rpcb_clnt, map, proc);
749 	rpc_release_client(rpcb_clnt);
750 	if (IS_ERR(child)) {
751 		/* rpcb_map_release() has freed the arguments */
752 		dprintk("RPC: %5u %s: rpc_run_task failed\n",
753 			task->tk_pid, __func__);
754 		return;
755 	}
756 
757 	xprt->stat.bind_count++;
758 	rpc_put_task(child);
759 	return;
760 
761 bailout_release_client:
762 	rpc_release_client(rpcb_clnt);
763 bailout_nofree:
764 	rpcb_wake_rpcbind_waiters(xprt, status);
765 	task->tk_status = status;
766 }
767 EXPORT_SYMBOL_GPL(rpcb_getport_async);
768 
769 /*
770  * Rpcbind child task calls this callback via tk_exit.
771  */
772 static void rpcb_getport_done(struct rpc_task *child, void *data)
773 {
774 	struct rpcbind_args *map = data;
775 	struct rpc_xprt *xprt = map->r_xprt;
776 	int status = child->tk_status;
777 
778 	/* Garbage reply: retry with a lesser rpcbind version */
779 	if (status == -EIO)
780 		status = -EPROTONOSUPPORT;
781 
782 	/* rpcbind server doesn't support this rpcbind protocol version */
783 	if (status == -EPROTONOSUPPORT)
784 		xprt->bind_index++;
785 
786 	if (status < 0) {
787 		/* rpcbind server not available on remote host? */
788 		xprt->ops->set_port(xprt, 0);
789 	} else if (map->r_port == 0) {
790 		/* Requested RPC service wasn't registered on remote host */
791 		xprt->ops->set_port(xprt, 0);
792 		status = -EACCES;
793 	} else {
794 		/* Succeeded */
795 		xprt->ops->set_port(xprt, map->r_port);
796 		xprt_set_bound(xprt);
797 		status = 0;
798 	}
799 
800 	dprintk("RPC: %5u rpcb_getport_done(status %d, port %u)\n",
801 			child->tk_pid, status, map->r_port);
802 
803 	map->r_status = status;
804 }
805 
806 /*
807  * XDR functions for rpcbind
808  */
809 
810 static void rpcb_enc_mapping(struct rpc_rqst *req, struct xdr_stream *xdr,
811 			     const struct rpcbind_args *rpcb)
812 {
813 	struct rpc_task *task = req->rq_task;
814 	__be32 *p;
815 
816 	dprintk("RPC: %5u encoding PMAP_%s call (%u, %u, %d, %u)\n",
817 			task->tk_pid, task->tk_msg.rpc_proc->p_name,
818 			rpcb->r_prog, rpcb->r_vers, rpcb->r_prot, rpcb->r_port);
819 
820 	p = xdr_reserve_space(xdr, RPCB_mappingargs_sz << 2);
821 	*p++ = cpu_to_be32(rpcb->r_prog);
822 	*p++ = cpu_to_be32(rpcb->r_vers);
823 	*p++ = cpu_to_be32(rpcb->r_prot);
824 	*p   = cpu_to_be32(rpcb->r_port);
825 }
826 
827 static int rpcb_dec_getport(struct rpc_rqst *req, struct xdr_stream *xdr,
828 			    struct rpcbind_args *rpcb)
829 {
830 	struct rpc_task *task = req->rq_task;
831 	unsigned long port;
832 	__be32 *p;
833 
834 	rpcb->r_port = 0;
835 
836 	p = xdr_inline_decode(xdr, 4);
837 	if (unlikely(p == NULL))
838 		return -EIO;
839 
840 	port = be32_to_cpup(p);
841 	dprintk("RPC: %5u PMAP_%s result: %lu\n", task->tk_pid,
842 			task->tk_msg.rpc_proc->p_name, port);
843 	if (unlikely(port > USHRT_MAX))
844 		return -EIO;
845 
846 	rpcb->r_port = port;
847 	return 0;
848 }
849 
850 static int rpcb_dec_set(struct rpc_rqst *req, struct xdr_stream *xdr,
851 			unsigned int *boolp)
852 {
853 	struct rpc_task *task = req->rq_task;
854 	__be32 *p;
855 
856 	p = xdr_inline_decode(xdr, 4);
857 	if (unlikely(p == NULL))
858 		return -EIO;
859 
860 	*boolp = 0;
861 	if (*p != xdr_zero)
862 		*boolp = 1;
863 
864 	dprintk("RPC: %5u RPCB_%s call %s\n",
865 			task->tk_pid, task->tk_msg.rpc_proc->p_name,
866 			(*boolp ? "succeeded" : "failed"));
867 	return 0;
868 }
869 
870 static void encode_rpcb_string(struct xdr_stream *xdr, const char *string,
871 			       const u32 maxstrlen)
872 {
873 	__be32 *p;
874 	u32 len;
875 
876 	len = strlen(string);
877 	BUG_ON(len > maxstrlen);
878 	p = xdr_reserve_space(xdr, 4 + len);
879 	xdr_encode_opaque(p, string, len);
880 }
881 
882 static void rpcb_enc_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
883 			     const struct rpcbind_args *rpcb)
884 {
885 	struct rpc_task *task = req->rq_task;
886 	__be32 *p;
887 
888 	dprintk("RPC: %5u encoding RPCB_%s call (%u, %u, '%s', '%s')\n",
889 			task->tk_pid, task->tk_msg.rpc_proc->p_name,
890 			rpcb->r_prog, rpcb->r_vers,
891 			rpcb->r_netid, rpcb->r_addr);
892 
893 	p = xdr_reserve_space(xdr, (RPCB_program_sz + RPCB_version_sz) << 2);
894 	*p++ = cpu_to_be32(rpcb->r_prog);
895 	*p = cpu_to_be32(rpcb->r_vers);
896 
897 	encode_rpcb_string(xdr, rpcb->r_netid, RPCBIND_MAXNETIDLEN);
898 	encode_rpcb_string(xdr, rpcb->r_addr, RPCBIND_MAXUADDRLEN);
899 	encode_rpcb_string(xdr, rpcb->r_owner, RPCB_MAXOWNERLEN);
900 }
901 
902 static int rpcb_dec_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
903 			    struct rpcbind_args *rpcb)
904 {
905 	struct sockaddr_storage address;
906 	struct sockaddr *sap = (struct sockaddr *)&address;
907 	struct rpc_task *task = req->rq_task;
908 	__be32 *p;
909 	u32 len;
910 
911 	rpcb->r_port = 0;
912 
913 	p = xdr_inline_decode(xdr, 4);
914 	if (unlikely(p == NULL))
915 		goto out_fail;
916 	len = be32_to_cpup(p);
917 
918 	/*
919 	 * If the returned universal address is a null string,
920 	 * the requested RPC service was not registered.
921 	 */
922 	if (len == 0) {
923 		dprintk("RPC: %5u RPCB reply: program not registered\n",
924 				task->tk_pid);
925 		return 0;
926 	}
927 
928 	if (unlikely(len > RPCBIND_MAXUADDRLEN))
929 		goto out_fail;
930 
931 	p = xdr_inline_decode(xdr, len);
932 	if (unlikely(p == NULL))
933 		goto out_fail;
934 	dprintk("RPC: %5u RPCB_%s reply: %s\n", task->tk_pid,
935 			task->tk_msg.rpc_proc->p_name, (char *)p);
936 
937 	if (rpc_uaddr2sockaddr(req->rq_xprt->xprt_net, (char *)p, len,
938 				sap, sizeof(address)) == 0)
939 		goto out_fail;
940 	rpcb->r_port = rpc_get_port(sap);
941 
942 	return 0;
943 
944 out_fail:
945 	dprintk("RPC: %5u malformed RPCB_%s reply\n",
946 			task->tk_pid, task->tk_msg.rpc_proc->p_name);
947 	return -EIO;
948 }
949 
950 /*
951  * Not all rpcbind procedures described in RFC 1833 are implemented
952  * since the Linux kernel RPC code requires only these.
953  */
954 
955 static struct rpc_procinfo rpcb_procedures2[] = {
956 	[RPCBPROC_SET] = {
957 		.p_proc		= RPCBPROC_SET,
958 		.p_encode	= (kxdreproc_t)rpcb_enc_mapping,
959 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
960 		.p_arglen	= RPCB_mappingargs_sz,
961 		.p_replen	= RPCB_setres_sz,
962 		.p_statidx	= RPCBPROC_SET,
963 		.p_timer	= 0,
964 		.p_name		= "SET",
965 	},
966 	[RPCBPROC_UNSET] = {
967 		.p_proc		= RPCBPROC_UNSET,
968 		.p_encode	= (kxdreproc_t)rpcb_enc_mapping,
969 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
970 		.p_arglen	= RPCB_mappingargs_sz,
971 		.p_replen	= RPCB_setres_sz,
972 		.p_statidx	= RPCBPROC_UNSET,
973 		.p_timer	= 0,
974 		.p_name		= "UNSET",
975 	},
976 	[RPCBPROC_GETPORT] = {
977 		.p_proc		= RPCBPROC_GETPORT,
978 		.p_encode	= (kxdreproc_t)rpcb_enc_mapping,
979 		.p_decode	= (kxdrdproc_t)rpcb_dec_getport,
980 		.p_arglen	= RPCB_mappingargs_sz,
981 		.p_replen	= RPCB_getportres_sz,
982 		.p_statidx	= RPCBPROC_GETPORT,
983 		.p_timer	= 0,
984 		.p_name		= "GETPORT",
985 	},
986 };
987 
988 static struct rpc_procinfo rpcb_procedures3[] = {
989 	[RPCBPROC_SET] = {
990 		.p_proc		= RPCBPROC_SET,
991 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
992 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
993 		.p_arglen	= RPCB_getaddrargs_sz,
994 		.p_replen	= RPCB_setres_sz,
995 		.p_statidx	= RPCBPROC_SET,
996 		.p_timer	= 0,
997 		.p_name		= "SET",
998 	},
999 	[RPCBPROC_UNSET] = {
1000 		.p_proc		= RPCBPROC_UNSET,
1001 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1002 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
1003 		.p_arglen	= RPCB_getaddrargs_sz,
1004 		.p_replen	= RPCB_setres_sz,
1005 		.p_statidx	= RPCBPROC_UNSET,
1006 		.p_timer	= 0,
1007 		.p_name		= "UNSET",
1008 	},
1009 	[RPCBPROC_GETADDR] = {
1010 		.p_proc		= RPCBPROC_GETADDR,
1011 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1012 		.p_decode	= (kxdrdproc_t)rpcb_dec_getaddr,
1013 		.p_arglen	= RPCB_getaddrargs_sz,
1014 		.p_replen	= RPCB_getaddrres_sz,
1015 		.p_statidx	= RPCBPROC_GETADDR,
1016 		.p_timer	= 0,
1017 		.p_name		= "GETADDR",
1018 	},
1019 };
1020 
1021 static struct rpc_procinfo rpcb_procedures4[] = {
1022 	[RPCBPROC_SET] = {
1023 		.p_proc		= RPCBPROC_SET,
1024 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1025 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
1026 		.p_arglen	= RPCB_getaddrargs_sz,
1027 		.p_replen	= RPCB_setres_sz,
1028 		.p_statidx	= RPCBPROC_SET,
1029 		.p_timer	= 0,
1030 		.p_name		= "SET",
1031 	},
1032 	[RPCBPROC_UNSET] = {
1033 		.p_proc		= RPCBPROC_UNSET,
1034 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1035 		.p_decode	= (kxdrdproc_t)rpcb_dec_set,
1036 		.p_arglen	= RPCB_getaddrargs_sz,
1037 		.p_replen	= RPCB_setres_sz,
1038 		.p_statidx	= RPCBPROC_UNSET,
1039 		.p_timer	= 0,
1040 		.p_name		= "UNSET",
1041 	},
1042 	[RPCBPROC_GETADDR] = {
1043 		.p_proc		= RPCBPROC_GETADDR,
1044 		.p_encode	= (kxdreproc_t)rpcb_enc_getaddr,
1045 		.p_decode	= (kxdrdproc_t)rpcb_dec_getaddr,
1046 		.p_arglen	= RPCB_getaddrargs_sz,
1047 		.p_replen	= RPCB_getaddrres_sz,
1048 		.p_statidx	= RPCBPROC_GETADDR,
1049 		.p_timer	= 0,
1050 		.p_name		= "GETADDR",
1051 	},
1052 };
1053 
1054 static struct rpcb_info rpcb_next_version[] = {
1055 	{
1056 		.rpc_vers	= RPCBVERS_2,
1057 		.rpc_proc	= &rpcb_procedures2[RPCBPROC_GETPORT],
1058 	},
1059 	{
1060 		.rpc_proc	= NULL,
1061 	},
1062 };
1063 
1064 static struct rpcb_info rpcb_next_version6[] = {
1065 	{
1066 		.rpc_vers	= RPCBVERS_4,
1067 		.rpc_proc	= &rpcb_procedures4[RPCBPROC_GETADDR],
1068 	},
1069 	{
1070 		.rpc_vers	= RPCBVERS_3,
1071 		.rpc_proc	= &rpcb_procedures3[RPCBPROC_GETADDR],
1072 	},
1073 	{
1074 		.rpc_proc	= NULL,
1075 	},
1076 };
1077 
1078 static struct rpc_version rpcb_version2 = {
1079 	.number		= RPCBVERS_2,
1080 	.nrprocs	= ARRAY_SIZE(rpcb_procedures2),
1081 	.procs		= rpcb_procedures2
1082 };
1083 
1084 static struct rpc_version rpcb_version3 = {
1085 	.number		= RPCBVERS_3,
1086 	.nrprocs	= ARRAY_SIZE(rpcb_procedures3),
1087 	.procs		= rpcb_procedures3
1088 };
1089 
1090 static struct rpc_version rpcb_version4 = {
1091 	.number		= RPCBVERS_4,
1092 	.nrprocs	= ARRAY_SIZE(rpcb_procedures4),
1093 	.procs		= rpcb_procedures4
1094 };
1095 
1096 static struct rpc_version *rpcb_version[] = {
1097 	NULL,
1098 	NULL,
1099 	&rpcb_version2,
1100 	&rpcb_version3,
1101 	&rpcb_version4
1102 };
1103 
1104 static struct rpc_stat rpcb_stats;
1105 
1106 static struct rpc_program rpcb_program = {
1107 	.name		= "rpcbind",
1108 	.number		= RPCBIND_PROGRAM,
1109 	.nrvers		= ARRAY_SIZE(rpcb_version),
1110 	.version	= rpcb_version,
1111 	.stats		= &rpcb_stats,
1112 };
1113