1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * In-kernel rpcbind client supporting versions 2, 3, and 4 of the rpcbind
   4 * protocol
   5 *
   6 * Based on RFC 1833: "Binding Protocols for ONC RPC Version 2" and
   7 * RFC 3530: "Network File System (NFS) version 4 Protocol"
   8 *
   9 * Original: Gilles Quillard, Bull Open Source, 2005 <gilles.quillard@bull.net>
  10 * Updated: Chuck Lever, Oracle Corporation, 2007 <chuck.lever@oracle.com>
  11 *
  12 * Descended from net/sunrpc/pmap_clnt.c,
  13 *  Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
  14 */
  15
  16#include <linux/module.h>
  17
  18#include <linux/types.h>
  19#include <linux/socket.h>
  20#include <linux/un.h>
  21#include <linux/in.h>
  22#include <linux/in6.h>
  23#include <linux/kernel.h>
  24#include <linux/errno.h>
  25#include <linux/mutex.h>
  26#include <linux/slab.h>
  27#include <net/ipv6.h>
  28
  29#include <linux/sunrpc/clnt.h>
  30#include <linux/sunrpc/addr.h>
  31#include <linux/sunrpc/sched.h>
  32#include <linux/sunrpc/xprtsock.h>
  33
  34#include <trace/events/sunrpc.h>
  35
  36#include "netns.h"
  37
  38#define RPCBIND_SOCK_PATHNAME	"/var/run/rpcbind.sock"
  39
  40#define RPCBIND_PROGRAM		(100000u)
  41#define RPCBIND_PORT		(111u)
  42
  43#define RPCBVERS_2		(2u)
  44#define RPCBVERS_3		(3u)
  45#define RPCBVERS_4		(4u)
  46
  47enum {
  48	RPCBPROC_NULL,
  49	RPCBPROC_SET,
  50	RPCBPROC_UNSET,
  51	RPCBPROC_GETPORT,
  52	RPCBPROC_GETADDR = 3,		/* alias for GETPORT */
  53	RPCBPROC_DUMP,
  54	RPCBPROC_CALLIT,
  55	RPCBPROC_BCAST = 5,		/* alias for CALLIT */
  56	RPCBPROC_GETTIME,
  57	RPCBPROC_UADDR2TADDR,
  58	RPCBPROC_TADDR2UADDR,
  59	RPCBPROC_GETVERSADDR,
  60	RPCBPROC_INDIRECT,
  61	RPCBPROC_GETADDRLIST,
  62	RPCBPROC_GETSTAT,
  63};
  64
  65/*
  66 * r_owner
  67 *
  68 * The "owner" is allowed to unset a service in the rpcbind database.
  69 *
  70 * For AF_LOCAL SET/UNSET requests, rpcbind treats this string as a
  71 * UID which it maps to a local user name via a password lookup.
  72 * In all other cases it is ignored.
  73 *
  74 * For SET/UNSET requests, user space provides a value, even for
  75 * network requests, and GETADDR uses an empty string.  We follow
  76 * those precedents here.
  77 */
  78#define RPCB_OWNER_STRING	"0"
  79#define RPCB_MAXOWNERLEN	sizeof(RPCB_OWNER_STRING)
  80
  81/*
  82 * XDR data type sizes
  83 */
  84#define RPCB_program_sz		(1)
  85#define RPCB_version_sz		(1)
  86#define RPCB_protocol_sz	(1)
  87#define RPCB_port_sz		(1)
  88#define RPCB_boolean_sz		(1)
  89
  90#define RPCB_netid_sz		(1 + XDR_QUADLEN(RPCBIND_MAXNETIDLEN))
  91#define RPCB_addr_sz		(1 + XDR_QUADLEN(RPCBIND_MAXUADDRLEN))
  92#define RPCB_ownerstring_sz	(1 + XDR_QUADLEN(RPCB_MAXOWNERLEN))
  93
  94/*
  95 * XDR argument and result sizes
  96 */
  97#define RPCB_mappingargs_sz	(RPCB_program_sz + RPCB_version_sz + \
  98				RPCB_protocol_sz + RPCB_port_sz)
  99#define RPCB_getaddrargs_sz	(RPCB_program_sz + RPCB_version_sz + \
 100				RPCB_netid_sz + RPCB_addr_sz + \
 101				RPCB_ownerstring_sz)
 102
 103#define RPCB_getportres_sz	RPCB_port_sz
 104#define RPCB_setres_sz		RPCB_boolean_sz
 105
 106/*
 107 * Note that RFC 1833 does not put any size restrictions on the
 108 * address string returned by the remote rpcbind database.
 109 */
 110#define RPCB_getaddrres_sz	RPCB_addr_sz
 111
 112static void			rpcb_getport_done(struct rpc_task *, void *);
 113static void			rpcb_map_release(void *data);
 114static const struct rpc_program	rpcb_program;
 115
 116struct rpcbind_args {
 117	struct rpc_xprt *	r_xprt;
 118
 119	u32			r_prog;
 120	u32			r_vers;
 121	u32			r_prot;
 122	unsigned short		r_port;
 123	const char *		r_netid;
 124	const char *		r_addr;
 125	const char *		r_owner;
 126
 127	int			r_status;
 128};
 129
 130static const struct rpc_procinfo rpcb_procedures2[];
 131static const struct rpc_procinfo rpcb_procedures3[];
 132static const struct rpc_procinfo rpcb_procedures4[];
 133
 134struct rpcb_info {
 135	u32			rpc_vers;
 136	const struct rpc_procinfo *rpc_proc;
 137};
 138
 139static const struct rpcb_info rpcb_next_version[];
 140static const struct rpcb_info rpcb_next_version6[];
 141
 142static const struct rpc_call_ops rpcb_getport_ops = {
 143	.rpc_call_done		= rpcb_getport_done,
 144	.rpc_release		= rpcb_map_release,
 145};
 146
 147static void rpcb_wake_rpcbind_waiters(struct rpc_xprt *xprt, int status)
 148{
 149	xprt_clear_binding(xprt);
 150	rpc_wake_up_status(&xprt->binding, status);
 151}
 152
 153static void rpcb_map_release(void *data)
 154{
 155	struct rpcbind_args *map = data;
 156
 157	rpcb_wake_rpcbind_waiters(map->r_xprt, map->r_status);
 158	xprt_put(map->r_xprt);
 159	kfree(map->r_addr);
 160	kfree(map);
 161}
 162
 163static int rpcb_get_local(struct net *net)
 164{
 165	int cnt;
 166	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 167
 168	spin_lock(&sn->rpcb_clnt_lock);
 169	if (sn->rpcb_users)
 170		sn->rpcb_users++;
 171	cnt = sn->rpcb_users;
 172	spin_unlock(&sn->rpcb_clnt_lock);
 173
 174	return cnt;
 175}
 176
 177void rpcb_put_local(struct net *net)
 178{
 179	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 180	struct rpc_clnt *clnt = sn->rpcb_local_clnt;
 181	struct rpc_clnt *clnt4 = sn->rpcb_local_clnt4;
 182	int shutdown = 0;
 183
 184	spin_lock(&sn->rpcb_clnt_lock);
 185	if (sn->rpcb_users) {
 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	}
 192	spin_unlock(&sn->rpcb_clnt_lock);
 193
 194	if (shutdown) {
 195		/*
 196		 * cleanup_rpcb_clnt - remove xprtsock's sysctls, unregister
 197		 */
 198		if (clnt4)
 199			rpc_shutdown_client(clnt4);
 200		if (clnt)
 201			rpc_shutdown_client(clnt);
 202	}
 203}
 204
 205static void rpcb_set_local(struct net *net, struct rpc_clnt *clnt,
 206			struct rpc_clnt *clnt4,
 207			bool is_af_local)
 208{
 209	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 210
 211	/* Protected by rpcb_create_local_mutex */
 212	sn->rpcb_local_clnt = clnt;
 213	sn->rpcb_local_clnt4 = clnt4;
 214	sn->rpcb_is_af_local = is_af_local ? 1 : 0;
 215	smp_wmb();
 216	sn->rpcb_users = 1;
 217}
 218
 219/*
 220 * Returns zero on success, otherwise a negative errno value
 221 * is returned.
 222 */
 223static int rpcb_create_local_unix(struct net *net)
 224{
 225	static const struct sockaddr_un rpcb_localaddr_rpcbind = {
 226		.sun_family		= AF_LOCAL,
 227		.sun_path		= RPCBIND_SOCK_PATHNAME,
 228	};
 229	struct rpc_create_args args = {
 230		.net		= net,
 231		.protocol	= XPRT_TRANSPORT_LOCAL,
 232		.address	= (struct sockaddr *)&rpcb_localaddr_rpcbind,
 233		.addrsize	= sizeof(rpcb_localaddr_rpcbind),
 234		.servername	= "localhost",
 235		.program	= &rpcb_program,
 236		.version	= RPCBVERS_2,
 237		.authflavor	= RPC_AUTH_NULL,
 238		.cred		= current_cred(),
 239		/*
 240		 * We turn off the idle timeout to prevent the kernel
 241		 * from automatically disconnecting the socket.
 242		 * Otherwise, we'd have to cache the mount namespace
 243		 * of the caller and somehow pass that to the socket
 244		 * reconnect code.
 245		 */
 246		.flags		= RPC_CLNT_CREATE_NO_IDLE_TIMEOUT,
 247	};
 248	struct rpc_clnt *clnt, *clnt4;
 249	int result = 0;
 250
 251	/*
 252	 * Because we requested an RPC PING at transport creation time,
 253	 * this works only if the user space portmapper is rpcbind, and
 254	 * it's listening on AF_LOCAL on the named socket.
 255	 */
 256	clnt = rpc_create(&args);
 257	if (IS_ERR(clnt)) {
 258		result = PTR_ERR(clnt);
 259		goto out;
 260	}
 261
 262	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
 263	if (IS_ERR(clnt4))
 264		clnt4 = NULL;
 265
 266	rpcb_set_local(net, clnt, clnt4, true);
 267
 268out:
 269	return result;
 270}
 271
 272/*
 273 * Returns zero on success, otherwise a negative errno value
 274 * is returned.
 275 */
 276static int rpcb_create_local_net(struct net *net)
 277{
 278	static const struct sockaddr_in rpcb_inaddr_loopback = {
 279		.sin_family		= AF_INET,
 280		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
 281		.sin_port		= htons(RPCBIND_PORT),
 282	};
 283	struct rpc_create_args args = {
 284		.net		= net,
 285		.protocol	= XPRT_TRANSPORT_TCP,
 286		.address	= (struct sockaddr *)&rpcb_inaddr_loopback,
 287		.addrsize	= sizeof(rpcb_inaddr_loopback),
 288		.servername	= "localhost",
 289		.program	= &rpcb_program,
 290		.version	= RPCBVERS_2,
 291		.authflavor	= RPC_AUTH_UNIX,
 292		.cred		= current_cred(),
 293		.flags		= RPC_CLNT_CREATE_NOPING,
 294	};
 295	struct rpc_clnt *clnt, *clnt4;
 296	int result = 0;
 297
 298	clnt = rpc_create(&args);
 299	if (IS_ERR(clnt)) {
 300		result = PTR_ERR(clnt);
 301		goto out;
 302	}
 303
 304	/*
 305	 * This results in an RPC ping.  On systems running portmapper,
 306	 * the v4 ping will fail.  Proceed anyway, but disallow rpcb
 307	 * v4 upcalls.
 308	 */
 309	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
 310	if (IS_ERR(clnt4))
 311		clnt4 = NULL;
 312
 313	rpcb_set_local(net, clnt, clnt4, false);
 314
 315out:
 316	return result;
 317}
 318
 319/*
 320 * Returns zero on success, otherwise a negative errno value
 321 * is returned.
 322 */
 323int rpcb_create_local(struct net *net)
 324{
 325	static DEFINE_MUTEX(rpcb_create_local_mutex);
 326	int result = 0;
 327
 328	if (rpcb_get_local(net))
 329		return result;
 330
 331	mutex_lock(&rpcb_create_local_mutex);
 332	if (rpcb_get_local(net))
 333		goto out;
 334
 335	if (rpcb_create_local_unix(net) != 0)
 336		result = rpcb_create_local_net(net);
 337
 338out:
 339	mutex_unlock(&rpcb_create_local_mutex);
 340	return result;
 341}
 342
 343static struct rpc_clnt *rpcb_create(struct net *net, const char *nodename,
 344				    const char *hostname,
 345				    struct sockaddr *srvaddr, size_t salen,
 346				    int proto, u32 version,
 347				    const struct cred *cred,
 348				    const struct rpc_timeout *timeo)
 349{
 350	struct rpc_create_args args = {
 351		.net		= net,
 352		.protocol	= proto,
 353		.address	= srvaddr,
 354		.addrsize	= salen,
 355		.timeout	= timeo,
 356		.servername	= hostname,
 357		.nodename	= nodename,
 358		.program	= &rpcb_program,
 359		.version	= version,
 360		.authflavor	= RPC_AUTH_UNIX,
 361		.cred		= cred,
 362		.flags		= (RPC_CLNT_CREATE_NOPING |
 363					RPC_CLNT_CREATE_NONPRIVPORT),
 364	};
 365
 366	switch (srvaddr->sa_family) {
 367	case AF_INET:
 368		((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
 369		break;
 370	case AF_INET6:
 371		((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
 372		break;
 373	default:
 374		return ERR_PTR(-EAFNOSUPPORT);
 375	}
 376
 377	return rpc_create(&args);
 378}
 379
 380static int rpcb_register_call(struct sunrpc_net *sn, struct rpc_clnt *clnt, struct rpc_message *msg, bool is_set)
 381{
 382	int flags = RPC_TASK_NOCONNECT;
 383	int error, result = 0;
 384
 385	if (is_set || !sn->rpcb_is_af_local)
 386		flags = RPC_TASK_SOFTCONN;
 387	msg->rpc_resp = &result;
 388
 389	error = rpc_call_sync(clnt, msg, flags);
 390	if (error < 0)
 391		return error;
 392
 393	if (!result)
 394		return -EACCES;
 395	return 0;
 396}
 397
 398/**
 399 * rpcb_register - set or unset a port registration with the local rpcbind svc
 400 * @net: target network namespace
 401 * @prog: RPC program number to bind
 402 * @vers: RPC version number to bind
 403 * @prot: transport protocol to register
 404 * @port: port value to register
 405 *
 406 * Returns zero if the registration request was dispatched successfully
 407 * and the rpcbind daemon returned success.  Otherwise, returns an errno
 408 * value that reflects the nature of the error (request could not be
 409 * dispatched, timed out, or rpcbind returned an error).
 410 *
 411 * RPC services invoke this function to advertise their contact
 412 * information via the system's rpcbind daemon.  RPC services
 413 * invoke this function once for each [program, version, transport]
 414 * tuple they wish to advertise.
 415 *
 416 * Callers may also unregister RPC services that are no longer
 417 * available by setting the passed-in port to zero.  This removes
 418 * all registered transports for [program, version] from the local
 419 * rpcbind database.
 420 *
 421 * This function uses rpcbind protocol version 2 to contact the
 422 * local rpcbind daemon.
 423 *
 424 * Registration works over both AF_INET and AF_INET6, and services
 425 * registered via this function are advertised as available for any
 426 * address.  If the local rpcbind daemon is listening on AF_INET6,
 427 * services registered via this function will be advertised on
 428 * IN6ADDR_ANY (ie available for all AF_INET and AF_INET6
 429 * addresses).
 430 */
 431int rpcb_register(struct net *net, u32 prog, u32 vers, int prot, unsigned short port)
 432{
 433	struct rpcbind_args map = {
 434		.r_prog		= prog,
 435		.r_vers		= vers,
 436		.r_prot		= prot,
 437		.r_port		= port,
 438	};
 439	struct rpc_message msg = {
 440		.rpc_argp	= &map,
 441	};
 442	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 443	bool is_set = false;
 444
 445	trace_pmap_register(prog, vers, prot, port);
 446
 447	msg.rpc_proc = &rpcb_procedures2[RPCBPROC_UNSET];
 448	if (port != 0) {
 449		msg.rpc_proc = &rpcb_procedures2[RPCBPROC_SET];
 450		is_set = true;
 451	}
 452
 453	return rpcb_register_call(sn, sn->rpcb_local_clnt, &msg, is_set);
 454}
 455
 456/*
 457 * Fill in AF_INET family-specific arguments to register
 458 */
 459static int rpcb_register_inet4(struct sunrpc_net *sn,
 460			       const struct sockaddr *sap,
 461			       struct rpc_message *msg)
 462{
 463	const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
 464	struct rpcbind_args *map = msg->rpc_argp;
 465	unsigned short port = ntohs(sin->sin_port);
 466	bool is_set = false;
 467	int result;
 468
 469	map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
 470
 471	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 472	if (port != 0) {
 473		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
 474		is_set = true;
 475	}
 476
 477	result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
 478	kfree(map->r_addr);
 479	return result;
 480}
 481
 482/*
 483 * Fill in AF_INET6 family-specific arguments to register
 484 */
 485static int rpcb_register_inet6(struct sunrpc_net *sn,
 486			       const struct sockaddr *sap,
 487			       struct rpc_message *msg)
 488{
 489	const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)sap;
 490	struct rpcbind_args *map = msg->rpc_argp;
 491	unsigned short port = ntohs(sin6->sin6_port);
 492	bool is_set = false;
 493	int result;
 494
 495	map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
 496
 497	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 498	if (port != 0) {
 499		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
 500		is_set = true;
 501	}
 502
 503	result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
 504	kfree(map->r_addr);
 505	return result;
 506}
 507
 508static int rpcb_unregister_all_protofamilies(struct sunrpc_net *sn,
 509					     struct rpc_message *msg)
 510{
 511	struct rpcbind_args *map = msg->rpc_argp;
 512
 513	trace_rpcb_unregister(map->r_prog, map->r_vers, map->r_netid);
 514
 515	map->r_addr = "";
 516	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 517
 518	return rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, false);
 519}
 520
 521/**
 522 * rpcb_v4_register - set or unset a port registration with the local rpcbind
 523 * @net: target network namespace
 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 */
 565int 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	trace_rpcb_register(map.r_prog, map.r_vers, map.r_addr, map.r_netid);
 586
 587	switch (address->sa_family) {
 588	case AF_INET:
 589		return rpcb_register_inet4(sn, address, &msg);
 590	case AF_INET6:
 591		return rpcb_register_inet6(sn, address, &msg);
 592	}
 593
 594	return -EAFNOSUPPORT;
 595}
 596
 597static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt,
 598		struct rpcbind_args *map, const struct rpc_procinfo *proc)
 599{
 600	struct rpc_message msg = {
 601		.rpc_proc = proc,
 602		.rpc_argp = map,
 603		.rpc_resp = map,
 604	};
 605	struct rpc_task_setup task_setup_data = {
 606		.rpc_client = rpcb_clnt,
 607		.rpc_message = &msg,
 608		.callback_ops = &rpcb_getport_ops,
 609		.callback_data = map,
 610		.flags = RPC_TASK_ASYNC | RPC_TASK_SOFTCONN,
 611	};
 612
 613	return rpc_run_task(&task_setup_data);
 614}
 615
 616/*
 617 * In the case where rpc clients have been cloned, we want to make
 618 * sure that we use the program number/version etc of the actual
 619 * owner of the xprt. To do so, we walk back up the tree of parents
 620 * to find whoever created the transport and/or whoever has the
 621 * autobind flag set.
 622 */
 623static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
 624{
 625	struct rpc_clnt *parent = clnt->cl_parent;
 626	struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
 627
 628	while (parent != clnt) {
 629		if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
 630			break;
 631		if (clnt->cl_autobind)
 632			break;
 633		clnt = parent;
 634		parent = parent->cl_parent;
 635	}
 636	return clnt;
 637}
 638
 639/**
 640 * rpcb_getport_async - obtain the port for a given RPC service on a given host
 641 * @task: task that is waiting for portmapper request
 642 *
 643 * This one can be called for an ongoing RPC request, and can be used in
 644 * an async (rpciod) context.
 645 */
 646void rpcb_getport_async(struct rpc_task *task)
 647{
 648	struct rpc_clnt *clnt;
 649	const struct rpc_procinfo *proc;
 650	u32 bind_version;
 651	struct rpc_xprt *xprt;
 652	struct rpc_clnt	*rpcb_clnt;
 653	struct rpcbind_args *map;
 654	struct rpc_task	*child;
 655	struct sockaddr_storage addr;
 656	struct sockaddr *sap = (struct sockaddr *)&addr;
 657	size_t salen;
 658	int status;
 659
 660	rcu_read_lock();
 661	clnt = rpcb_find_transport_owner(task->tk_client);
 662	rcu_read_unlock();
 663	xprt = xprt_get(task->tk_xprt);
 664
 665	/* Put self on the wait queue to ensure we get notified if
 666	 * some other task is already attempting to bind the port */
 667	rpc_sleep_on_timeout(&xprt->binding, task,
 668			NULL, jiffies + xprt->bind_timeout);
 669
 670	if (xprt_test_and_set_binding(xprt)) {
 671		xprt_put(xprt);
 672		return;
 673	}
 674
 675	/* Someone else may have bound if we slept */
 676	if (xprt_bound(xprt)) {
 677		status = 0;
 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		goto bailout_nofree;
 697	}
 698	if (proc == NULL) {
 699		xprt->bind_index = 0;
 700		status = -EPFNOSUPPORT;
 701		goto bailout_nofree;
 702	}
 703
 704	trace_rpcb_getport(clnt, task, bind_version);
 705
 706	rpcb_clnt = rpcb_create(xprt->xprt_net,
 707				clnt->cl_nodename,
 708				xprt->servername, sap, salen,
 709				xprt->prot, bind_version,
 710				clnt->cl_cred,
 711				task->tk_client->cl_timeout);
 712	if (IS_ERR(rpcb_clnt)) {
 713		status = PTR_ERR(rpcb_clnt);
 714		goto bailout_nofree;
 715	}
 716
 717	map = kzalloc(sizeof(struct rpcbind_args), rpc_task_gfp_mask());
 718	if (!map) {
 719		status = -ENOMEM;
 720		goto bailout_release_client;
 721	}
 722	map->r_prog = clnt->cl_prog;
 723	map->r_vers = clnt->cl_vers;
 724	map->r_prot = xprt->prot;
 725	map->r_port = 0;
 726	map->r_xprt = xprt;
 727	map->r_status = -EIO;
 728
 729	switch (bind_version) {
 730	case RPCBVERS_4:
 731	case RPCBVERS_3:
 732		map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
 733		map->r_addr = rpc_sockaddr2uaddr(sap, rpc_task_gfp_mask());
 734		if (!map->r_addr) {
 735			status = -ENOMEM;
 736			goto bailout_free_args;
 737		}
 738		map->r_owner = "";
 739		break;
 740	case RPCBVERS_2:
 741		map->r_addr = NULL;
 742		break;
 743	default:
 744		BUG();
 745	}
 746
 747	child = rpcb_call_async(rpcb_clnt, map, proc);
 748	rpc_release_client(rpcb_clnt);
 749
 750	xprt->stat.bind_count++;
 751	rpc_put_task(child);
 752	return;
 753
 754bailout_free_args:
 755	kfree(map);
 756bailout_release_client:
 757	rpc_release_client(rpcb_clnt);
 758bailout_nofree:
 759	rpcb_wake_rpcbind_waiters(xprt, status);
 760	task->tk_status = status;
 761	xprt_put(xprt);
 762}
 763EXPORT_SYMBOL_GPL(rpcb_getport_async);
 764
 765/*
 766 * Rpcbind child task calls this callback via tk_exit.
 767 */
 768static void rpcb_getport_done(struct rpc_task *child, void *data)
 769{
 770	struct rpcbind_args *map = data;
 771	struct rpc_xprt *xprt = map->r_xprt;
 772
 773	map->r_status = child->tk_status;
 774
 775	/* Garbage reply: retry with a lesser rpcbind version */
 776	if (map->r_status == -EIO)
 777		map->r_status = -EPROTONOSUPPORT;
 778
 779	/* rpcbind server doesn't support this rpcbind protocol version */
 780	if (map->r_status == -EPROTONOSUPPORT)
 781		xprt->bind_index++;
 782
 783	if (map->r_status < 0) {
 784		/* rpcbind server not available on remote host? */
 785		map->r_port = 0;
 786
 787	} else if (map->r_port == 0) {
 788		/* Requested RPC service wasn't registered on remote host */
 789		map->r_status = -EACCES;
 790	} else {
 791		/* Succeeded */
 792		map->r_status = 0;
 793	}
 794
 795	trace_rpcb_setport(child, map->r_status, map->r_port);
 796	xprt->ops->set_port(xprt, map->r_port);
 797	if (map->r_port)
 798		xprt_set_bound(xprt);
 799}
 800
 801/*
 802 * XDR functions for rpcbind
 803 */
 804
 805static void rpcb_enc_mapping(struct rpc_rqst *req, struct xdr_stream *xdr,
 806			     const void *data)
 807{
 808	const struct rpcbind_args *rpcb = data;
 809	__be32 *p;
 810
 811	p = xdr_reserve_space(xdr, RPCB_mappingargs_sz << 2);
 812	*p++ = cpu_to_be32(rpcb->r_prog);
 813	*p++ = cpu_to_be32(rpcb->r_vers);
 814	*p++ = cpu_to_be32(rpcb->r_prot);
 815	*p   = cpu_to_be32(rpcb->r_port);
 816}
 817
 818static int rpcb_dec_getport(struct rpc_rqst *req, struct xdr_stream *xdr,
 819			    void *data)
 820{
 821	struct rpcbind_args *rpcb = data;
 822	unsigned long port;
 823	__be32 *p;
 824
 825	rpcb->r_port = 0;
 826
 827	p = xdr_inline_decode(xdr, 4);
 828	if (unlikely(p == NULL))
 829		return -EIO;
 830
 831	port = be32_to_cpup(p);
 832	if (unlikely(port > USHRT_MAX))
 833		return -EIO;
 834
 835	rpcb->r_port = port;
 836	return 0;
 837}
 838
 839static int rpcb_dec_set(struct rpc_rqst *req, struct xdr_stream *xdr,
 840			void *data)
 841{
 842	unsigned int *boolp = data;
 843	__be32 *p;
 844
 845	p = xdr_inline_decode(xdr, 4);
 846	if (unlikely(p == NULL))
 847		return -EIO;
 848
 849	*boolp = 0;
 850	if (*p != xdr_zero)
 851		*boolp = 1;
 852	return 0;
 853}
 854
 855static void encode_rpcb_string(struct xdr_stream *xdr, const char *string,
 856			       const u32 maxstrlen)
 857{
 858	__be32 *p;
 859	u32 len;
 860
 861	len = strlen(string);
 862	WARN_ON_ONCE(len > maxstrlen);
 863	if (len > maxstrlen)
 864		/* truncate and hope for the best */
 865		len = maxstrlen;
 866	p = xdr_reserve_space(xdr, 4 + len);
 867	xdr_encode_opaque(p, string, len);
 868}
 869
 870static void rpcb_enc_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
 871			     const void *data)
 872{
 873	const struct rpcbind_args *rpcb = data;
 874	__be32 *p;
 875
 876	p = xdr_reserve_space(xdr, (RPCB_program_sz + RPCB_version_sz) << 2);
 877	*p++ = cpu_to_be32(rpcb->r_prog);
 878	*p = cpu_to_be32(rpcb->r_vers);
 879
 880	encode_rpcb_string(xdr, rpcb->r_netid, RPCBIND_MAXNETIDLEN);
 881	encode_rpcb_string(xdr, rpcb->r_addr, RPCBIND_MAXUADDRLEN);
 882	encode_rpcb_string(xdr, rpcb->r_owner, RPCB_MAXOWNERLEN);
 883}
 884
 885static int rpcb_dec_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
 886			    void *data)
 887{
 888	struct rpcbind_args *rpcb = data;
 889	struct sockaddr_storage address;
 890	struct sockaddr *sap = (struct sockaddr *)&address;
 891	__be32 *p;
 892	u32 len;
 893
 894	rpcb->r_port = 0;
 895
 896	p = xdr_inline_decode(xdr, 4);
 897	if (unlikely(p == NULL))
 898		goto out_fail;
 899	len = be32_to_cpup(p);
 900
 901	/*
 902	 * If the returned universal address is a null string,
 903	 * the requested RPC service was not registered.
 904	 */
 905	if (len == 0)
 906		return 0;
 907
 908	if (unlikely(len > RPCBIND_MAXUADDRLEN))
 909		goto out_fail;
 910
 911	p = xdr_inline_decode(xdr, len);
 912	if (unlikely(p == NULL))
 913		goto out_fail;
 914
 915	if (rpc_uaddr2sockaddr(req->rq_xprt->xprt_net, (char *)p, len,
 916				sap, sizeof(address)) == 0)
 917		goto out_fail;
 918	rpcb->r_port = rpc_get_port(sap);
 919
 920	return 0;
 921
 922out_fail:
 923	return -EIO;
 924}
 925
 926/*
 927 * Not all rpcbind procedures described in RFC 1833 are implemented
 928 * since the Linux kernel RPC code requires only these.
 929 */
 930
 931static const struct rpc_procinfo rpcb_procedures2[] = {
 932	[RPCBPROC_SET] = {
 933		.p_proc		= RPCBPROC_SET,
 934		.p_encode	= rpcb_enc_mapping,
 935		.p_decode	= rpcb_dec_set,
 936		.p_arglen	= RPCB_mappingargs_sz,
 937		.p_replen	= RPCB_setres_sz,
 938		.p_statidx	= RPCBPROC_SET,
 939		.p_timer	= 0,
 940		.p_name		= "SET",
 941	},
 942	[RPCBPROC_UNSET] = {
 943		.p_proc		= RPCBPROC_UNSET,
 944		.p_encode	= rpcb_enc_mapping,
 945		.p_decode	= rpcb_dec_set,
 946		.p_arglen	= RPCB_mappingargs_sz,
 947		.p_replen	= RPCB_setres_sz,
 948		.p_statidx	= RPCBPROC_UNSET,
 949		.p_timer	= 0,
 950		.p_name		= "UNSET",
 951	},
 952	[RPCBPROC_GETPORT] = {
 953		.p_proc		= RPCBPROC_GETPORT,
 954		.p_encode	= rpcb_enc_mapping,
 955		.p_decode	= rpcb_dec_getport,
 956		.p_arglen	= RPCB_mappingargs_sz,
 957		.p_replen	= RPCB_getportres_sz,
 958		.p_statidx	= RPCBPROC_GETPORT,
 959		.p_timer	= 0,
 960		.p_name		= "GETPORT",
 961	},
 962};
 963
 964static const struct rpc_procinfo rpcb_procedures3[] = {
 965	[RPCBPROC_SET] = {
 966		.p_proc		= RPCBPROC_SET,
 967		.p_encode	= rpcb_enc_getaddr,
 968		.p_decode	= rpcb_dec_set,
 969		.p_arglen	= RPCB_getaddrargs_sz,
 970		.p_replen	= RPCB_setres_sz,
 971		.p_statidx	= RPCBPROC_SET,
 972		.p_timer	= 0,
 973		.p_name		= "SET",
 974	},
 975	[RPCBPROC_UNSET] = {
 976		.p_proc		= RPCBPROC_UNSET,
 977		.p_encode	= rpcb_enc_getaddr,
 978		.p_decode	= rpcb_dec_set,
 979		.p_arglen	= RPCB_getaddrargs_sz,
 980		.p_replen	= RPCB_setres_sz,
 981		.p_statidx	= RPCBPROC_UNSET,
 982		.p_timer	= 0,
 983		.p_name		= "UNSET",
 984	},
 985	[RPCBPROC_GETADDR] = {
 986		.p_proc		= RPCBPROC_GETADDR,
 987		.p_encode	= rpcb_enc_getaddr,
 988		.p_decode	= rpcb_dec_getaddr,
 989		.p_arglen	= RPCB_getaddrargs_sz,
 990		.p_replen	= RPCB_getaddrres_sz,
 991		.p_statidx	= RPCBPROC_GETADDR,
 992		.p_timer	= 0,
 993		.p_name		= "GETADDR",
 994	},
 995};
 996
 997static const struct rpc_procinfo rpcb_procedures4[] = {
 998	[RPCBPROC_SET] = {
 999		.p_proc		= RPCBPROC_SET,
1000		.p_encode	= rpcb_enc_getaddr,
1001		.p_decode	= rpcb_dec_set,
1002		.p_arglen	= RPCB_getaddrargs_sz,
1003		.p_replen	= RPCB_setres_sz,
1004		.p_statidx	= RPCBPROC_SET,
1005		.p_timer	= 0,
1006		.p_name		= "SET",
1007	},
1008	[RPCBPROC_UNSET] = {
1009		.p_proc		= RPCBPROC_UNSET,
1010		.p_encode	= rpcb_enc_getaddr,
1011		.p_decode	= rpcb_dec_set,
1012		.p_arglen	= RPCB_getaddrargs_sz,
1013		.p_replen	= RPCB_setres_sz,
1014		.p_statidx	= RPCBPROC_UNSET,
1015		.p_timer	= 0,
1016		.p_name		= "UNSET",
1017	},
1018	[RPCBPROC_GETADDR] = {
1019		.p_proc		= RPCBPROC_GETADDR,
1020		.p_encode	= rpcb_enc_getaddr,
1021		.p_decode	= rpcb_dec_getaddr,
1022		.p_arglen	= RPCB_getaddrargs_sz,
1023		.p_replen	= RPCB_getaddrres_sz,
1024		.p_statidx	= RPCBPROC_GETADDR,
1025		.p_timer	= 0,
1026		.p_name		= "GETADDR",
1027	},
1028};
1029
1030static const struct rpcb_info rpcb_next_version[] = {
1031	{
1032		.rpc_vers	= RPCBVERS_2,
1033		.rpc_proc	= &rpcb_procedures2[RPCBPROC_GETPORT],
1034	},
1035	{
1036		.rpc_proc	= NULL,
1037	},
1038};
1039
1040static const struct rpcb_info rpcb_next_version6[] = {
1041	{
1042		.rpc_vers	= RPCBVERS_4,
1043		.rpc_proc	= &rpcb_procedures4[RPCBPROC_GETADDR],
1044	},
1045	{
1046		.rpc_vers	= RPCBVERS_3,
1047		.rpc_proc	= &rpcb_procedures3[RPCBPROC_GETADDR],
1048	},
1049	{
1050		.rpc_proc	= NULL,
1051	},
1052};
1053
1054static unsigned int rpcb_version2_counts[ARRAY_SIZE(rpcb_procedures2)];
1055static const struct rpc_version rpcb_version2 = {
1056	.number		= RPCBVERS_2,
1057	.nrprocs	= ARRAY_SIZE(rpcb_procedures2),
1058	.procs		= rpcb_procedures2,
1059	.counts		= rpcb_version2_counts,
1060};
1061
1062static unsigned int rpcb_version3_counts[ARRAY_SIZE(rpcb_procedures3)];
1063static const struct rpc_version rpcb_version3 = {
1064	.number		= RPCBVERS_3,
1065	.nrprocs	= ARRAY_SIZE(rpcb_procedures3),
1066	.procs		= rpcb_procedures3,
1067	.counts		= rpcb_version3_counts,
1068};
1069
1070static unsigned int rpcb_version4_counts[ARRAY_SIZE(rpcb_procedures4)];
1071static const struct rpc_version rpcb_version4 = {
1072	.number		= RPCBVERS_4,
1073	.nrprocs	= ARRAY_SIZE(rpcb_procedures4),
1074	.procs		= rpcb_procedures4,
1075	.counts		= rpcb_version4_counts,
1076};
1077
1078static const struct rpc_version *rpcb_version[] = {
1079	NULL,
1080	NULL,
1081	&rpcb_version2,
1082	&rpcb_version3,
1083	&rpcb_version4
1084};
1085
1086static struct rpc_stat rpcb_stats;
1087
1088static const struct rpc_program rpcb_program = {
1089	.name		= "rpcbind",
1090	.number		= RPCBIND_PROGRAM,
1091	.nrvers		= ARRAY_SIZE(rpcb_version),
1092	.version	= rpcb_version,
1093	.stats		= &rpcb_stats,
1094};