net/sunrpc/clnt.c

   1 /*
   2  *  linux/net/sunrpc/clnt.c
   3  *
   4  *  This file contains the high-level RPC interface.
   5  *  It is modeled as a finite state machine to support both synchronous
   6  *  and asynchronous requests.
   7  *
   8  *  -   RPC header generation and argument serialization.
   9  *  -   Credential refresh.
  10  *  -   TCP connect handling.
  11  *  -   Retry of operation when it is suspected the operation failed because
  12  *      of uid squashing on the server, or when the credentials were stale
  13  *      and need to be refreshed, or when a packet was damaged in transit.
  14  *      This may be have to be moved to the VFS layer.
  15  *
  16  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  17  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  18  */
  19
  20
  21 #include <linux/module.h>
  22 #include <linux/types.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/mm.h>
  25 #include <linux/namei.h>
  26 #include <linux/mount.h>
  27 #include <linux/slab.h>
  28 #include <linux/rcupdate.h>
  29 #include <linux/utsname.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/in.h>
  32 #include <linux/in6.h>
  33 #include <linux/un.h>
  34
  35 #include <linux/sunrpc/clnt.h>
  36 #include <linux/sunrpc/addr.h>
  37 #include <linux/sunrpc/rpc_pipe_fs.h>
  38 #include <linux/sunrpc/metrics.h>
  39 #include <linux/sunrpc/bc_xprt.h>
  40 #include <trace/events/sunrpc.h>
  41
  42 #include "sunrpc.h"
  43 #include "netns.h"
  44
  45 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  46 # define RPCDBG_FACILITY        RPCDBG_CALL
  47 #endif
  48
  49 #define dprint_status(t)                                        \
  50         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  51                         __func__, t->tk_status)
  52
  53 /*
  54  * All RPC clients are linked into this list
  55  */
  56
  57 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  58
  59
  60 static void     call_start(struct rpc_task *task);
  61 static void     call_reserve(struct rpc_task *task);
  62 static void     call_reserveresult(struct rpc_task *task);
  63 static void     call_allocate(struct rpc_task *task);
  64 static void     call_decode(struct rpc_task *task);
  65 static void     call_bind(struct rpc_task *task);
  66 static void     call_bind_status(struct rpc_task *task);
  67 static void     call_transmit(struct rpc_task *task);
  68 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
  69 static void     call_bc_transmit(struct rpc_task *task);
  70 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
  71 static void     call_status(struct rpc_task *task);
  72 static void     call_transmit_status(struct rpc_task *task);
  73 static void     call_refresh(struct rpc_task *task);
  74 static void     call_refreshresult(struct rpc_task *task);
  75 static void     call_timeout(struct rpc_task *task);
  76 static void     call_connect(struct rpc_task *task);
  77 static void     call_connect_status(struct rpc_task *task);
  78
  79 static __be32   *rpc_encode_header(struct rpc_task *task);
  80 static __be32   *rpc_verify_header(struct rpc_task *task);
  81 static int      rpc_ping(struct rpc_clnt *clnt);
  82
  83 static void rpc_register_client(struct rpc_clnt *clnt)
  84 {
  85         struct net *net = rpc_net_ns(clnt);
  86         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
  87
  88         spin_lock(&sn->rpc_client_lock);
  89         list_add(&clnt->cl_clients, &sn->all_clients);
  90         spin_unlock(&sn->rpc_client_lock);
  91 }
  92
  93 static void rpc_unregister_client(struct rpc_clnt *clnt)
  94 {
  95         struct net *net = rpc_net_ns(clnt);
  96         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
  97
  98         spin_lock(&sn->rpc_client_lock);
  99         list_del(&clnt->cl_clients);
 100         spin_unlock(&sn->rpc_client_lock);
 101 }
 102
 103 static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
 104 {
 105         rpc_remove_client_dir(clnt);
 106 }
 107
 108 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
 109 {
 110         struct net *net = rpc_net_ns(clnt);
 111         struct super_block *pipefs_sb;
 112
 113         pipefs_sb = rpc_get_sb_net(net);
 114         if (pipefs_sb) {
 115                 __rpc_clnt_remove_pipedir(clnt);
 116                 rpc_put_sb_net(net);
 117         }
 118 }
 119
 120 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
 121                                     struct rpc_clnt *clnt)
 122 {
 123         static uint32_t clntid;
 124         const char *dir_name = clnt->cl_program->pipe_dir_name;
 125         char name[15];
 126         struct dentry *dir, *dentry;
 127
 128         dir = rpc_d_lookup_sb(sb, dir_name);
 129         if (dir == NULL) {
 130                 pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name);
 131                 return dir;
 132         }
 133         for (;;) {
 134                 snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
 135                 name[sizeof(name) - 1] = '\0';
 136                 dentry = rpc_create_client_dir(dir, name, clnt);
 137                 if (!IS_ERR(dentry))
 138                         break;
 139                 if (dentry == ERR_PTR(-EEXIST))
 140                         continue;
 141                 printk(KERN_INFO "RPC: Couldn't create pipefs entry"
 142                                 " %s/%s, error %ld\n",
 143                                 dir_name, name, PTR_ERR(dentry));
 144                 break;
 145         }
 146         dput(dir);
 147         return dentry;
 148 }
 149
 150 static int
 151 rpc_setup_pipedir(struct super_block *pipefs_sb, struct rpc_clnt *clnt)
 152 {
 153         struct dentry *dentry;
 154
 155         if (clnt->cl_program->pipe_dir_name != NULL) {
 156                 dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt);
 157                 if (IS_ERR(dentry))
 158                         return PTR_ERR(dentry);
 159         }
 160         return 0;
 161 }
 162
 163 static int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event)
 164 {
 165         if (clnt->cl_program->pipe_dir_name == NULL)
 166                 return 1;
 167
 168         switch (event) {
 169         case RPC_PIPEFS_MOUNT:
 170                 if (clnt->cl_pipedir_objects.pdh_dentry != NULL)
 171                         return 1;
 172                 if (atomic_read(&clnt->cl_count) == 0)
 173                         return 1;
 174                 break;
 175         case RPC_PIPEFS_UMOUNT:
 176                 if (clnt->cl_pipedir_objects.pdh_dentry == NULL)
 177                         return 1;
 178                 break;
 179         }
 180         return 0;
 181 }
 182
 183 static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event,
 184                                    struct super_block *sb)
 185 {
 186         struct dentry *dentry;
 187         int err = 0;
 188
 189         switch (event) {
 190         case RPC_PIPEFS_MOUNT:
 191                 dentry = rpc_setup_pipedir_sb(sb, clnt);
 192                 if (!dentry)
 193                         return -ENOENT;
 194                 if (IS_ERR(dentry))
 195                         return PTR_ERR(dentry);
 196                 break;
 197         case RPC_PIPEFS_UMOUNT:
 198                 __rpc_clnt_remove_pipedir(clnt);
 199                 break;
 200         default:
 201                 printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event);
 202                 return -ENOTSUPP;
 203         }
 204         return err;
 205 }
 206
 207 static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,
 208                                 struct super_block *sb)
 209 {
 210         int error = 0;
 211
 212         for (;; clnt = clnt->cl_parent) {
 213                 if (!rpc_clnt_skip_event(clnt, event))
 214                         error = __rpc_clnt_handle_event(clnt, event, sb);
 215                 if (error || clnt == clnt->cl_parent)
 216                         break;
 217         }
 218         return error;
 219 }
 220
 221 static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
 222 {
 223         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 224         struct rpc_clnt *clnt;
 225
 226         spin_lock(&sn->rpc_client_lock);
 227         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
 228                 if (rpc_clnt_skip_event(clnt, event))
 229                         continue;
 230                 spin_unlock(&sn->rpc_client_lock);
 231                 return clnt;
 232         }
 233         spin_unlock(&sn->rpc_client_lock);
 234         return NULL;
 235 }
 236
 237 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 238                             void *ptr)
 239 {
 240         struct super_block *sb = ptr;
 241         struct rpc_clnt *clnt;
 242         int error = 0;
 243
 244         while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
 245                 error = __rpc_pipefs_event(clnt, event, sb);
 246                 if (error)
 247                         break;
 248         }
 249         return error;
 250 }
 251
 252 static struct notifier_block rpc_clients_block = {
 253         .notifier_call  = rpc_pipefs_event,
 254         .priority       = SUNRPC_PIPEFS_RPC_PRIO,
 255 };
 256
 257 int rpc_clients_notifier_register(void)
 258 {
 259         return rpc_pipefs_notifier_register(&rpc_clients_block);
 260 }
 261
 262 void rpc_clients_notifier_unregister(void)
 263 {
 264         return rpc_pipefs_notifier_unregister(&rpc_clients_block);
 265 }
 266
 267 static struct rpc_xprt *rpc_clnt_set_transport(struct rpc_clnt *clnt,
 268                 struct rpc_xprt *xprt,
 269                 const struct rpc_timeout *timeout)
 270 {
 271         struct rpc_xprt *old;
 272
 273         spin_lock(&clnt->cl_lock);
 274         old = rcu_dereference_protected(clnt->cl_xprt,
 275                         lockdep_is_held(&clnt->cl_lock));
 276
 277         if (!xprt_bound(xprt))
 278                 clnt->cl_autobind = 1;
 279
 280         clnt->cl_timeout = timeout;
 281         rcu_assign_pointer(clnt->cl_xprt, xprt);
 282         spin_unlock(&clnt->cl_lock);
 283
 284         return old;
 285 }
 286
 287 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
 288 {
 289         clnt->cl_nodelen = strlcpy(clnt->cl_nodename,
 290                         nodename, sizeof(clnt->cl_nodename));
 291 }
 292
 293 static int rpc_client_register(struct rpc_clnt *clnt,
 294                                rpc_authflavor_t pseudoflavor,
 295                                const char *client_name)
 296 {
 297         struct rpc_auth_create_args auth_args = {
 298                 .pseudoflavor = pseudoflavor,
 299                 .target_name = client_name,
 300         };
 301         struct rpc_auth *auth;
 302         struct net *net = rpc_net_ns(clnt);
 303         struct super_block *pipefs_sb;
 304         int err;
 305
 306         rpc_clnt_debugfs_register(clnt);
 307
 308         pipefs_sb = rpc_get_sb_net(net);
 309         if (pipefs_sb) {
 310                 err = rpc_setup_pipedir(pipefs_sb, clnt);
 311                 if (err)
 312                         goto out;
 313         }
 314
 315         rpc_register_client(clnt);
 316         if (pipefs_sb)
 317                 rpc_put_sb_net(net);
 318
 319         auth = rpcauth_create(&auth_args, clnt);
 320         if (IS_ERR(auth)) {
 321                 dprintk("RPC:       Couldn't create auth handle (flavor %u)\n",
 322                                 pseudoflavor);
 323                 err = PTR_ERR(auth);
 324                 goto err_auth;
 325         }
 326         return 0;
 327 err_auth:
 328         pipefs_sb = rpc_get_sb_net(net);
 329         rpc_unregister_client(clnt);
 330         __rpc_clnt_remove_pipedir(clnt);
 331 out:
 332         if (pipefs_sb)
 333                 rpc_put_sb_net(net);
 334         rpc_clnt_debugfs_unregister(clnt);
 335         return err;
 336 }
 337
 338 static DEFINE_IDA(rpc_clids);
 339
 340 static int rpc_alloc_clid(struct rpc_clnt *clnt)
 341 {
 342         int clid;
 343
 344         clid = ida_simple_get(&rpc_clids, 0, 0, GFP_KERNEL);
 345         if (clid < 0)
 346                 return clid;
 347         clnt->cl_clid = clid;
 348         return 0;
 349 }
 350
 351 static void rpc_free_clid(struct rpc_clnt *clnt)
 352 {
 353         ida_simple_remove(&rpc_clids, clnt->cl_clid);
 354 }
 355
 356 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
 357                 struct rpc_xprt *xprt,
 358                 struct rpc_clnt *parent)
 359 {
 360         const struct rpc_program *program = args->program;
 361         const struct rpc_version *version;
 362         struct rpc_clnt *clnt = NULL;
 363         const struct rpc_timeout *timeout;
 364         const char *nodename = args->nodename;
 365         int err;
 366
 367         /* sanity check the name before trying to print it */
 368         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 369                         program->name, args->servername, xprt);
 370
 371         err = rpciod_up();
 372         if (err)
 373                 goto out_no_rpciod;
 374
 375         err = -EINVAL;
 376         if (args->version >= program->nrvers)
 377                 goto out_err;
 378         version = program->version[args->version];
 379         if (version == NULL)
 380                 goto out_err;
 381
 382         err = -ENOMEM;
 383         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 384         if (!clnt)
 385                 goto out_err;
 386         clnt->cl_parent = parent ? : clnt;
 387
 388         err = rpc_alloc_clid(clnt);
 389         if (err)
 390                 goto out_no_clid;
 391
 392         clnt->cl_procinfo = version->procs;
 393         clnt->cl_maxproc  = version->nrprocs;
 394         clnt->cl_prog     = args->prognumber ? : program->number;
 395         clnt->cl_vers     = version->number;
 396         clnt->cl_stats    = program->stats;
 397         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 398         rpc_init_pipe_dir_head(&clnt->cl_pipedir_objects);
 399         err = -ENOMEM;
 400         if (clnt->cl_metrics == NULL)
 401                 goto out_no_stats;
 402         clnt->cl_program  = program;
 403         INIT_LIST_HEAD(&clnt->cl_tasks);
 404         spin_lock_init(&clnt->cl_lock);
 405
 406         timeout = xprt->timeout;
 407         if (args->timeout != NULL) {
 408                 memcpy(&clnt->cl_timeout_default, args->timeout,
 409                                 sizeof(clnt->cl_timeout_default));
 410                 timeout = &clnt->cl_timeout_default;
 411         }
 412
 413         rpc_clnt_set_transport(clnt, xprt, timeout);
 414
 415         clnt->cl_rtt = &clnt->cl_rtt_default;
 416         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 417
 418         atomic_set(&clnt->cl_count, 1);
 419
 420         if (nodename == NULL)
 421                 nodename = utsname()->nodename;
 422         /* save the nodename */
 423         rpc_clnt_set_nodename(clnt, nodename);
 424
 425         err = rpc_client_register(clnt, args->authflavor, args->client_name);
 426         if (err)
 427                 goto out_no_path;
 428         if (parent)
 429                 atomic_inc(&parent->cl_count);
 430         return clnt;
 431
 432 out_no_path:
 433         rpc_free_iostats(clnt->cl_metrics);
 434 out_no_stats:
 435         rpc_free_clid(clnt);
 436 out_no_clid:
 437         kfree(clnt);
 438 out_err:
 439         rpciod_down();
 440 out_no_rpciod:
 441         xprt_put(xprt);
 442         return ERR_PTR(err);
 443 }
 444
 445 struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args,
 446                                         struct rpc_xprt *xprt)
 447 {
 448         struct rpc_clnt *clnt = NULL;
 449
 450         clnt = rpc_new_client(args, xprt, NULL);
 451         if (IS_ERR(clnt))
 452                 return clnt;
 453
 454         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 455                 int err = rpc_ping(clnt);
 456                 if (err != 0) {
 457                         rpc_shutdown_client(clnt);
 458                         return ERR_PTR(err);
 459                 }
 460         }
 461
 462         clnt->cl_softrtry = 1;
 463         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 464                 clnt->cl_softrtry = 0;
 465
 466         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 467                 clnt->cl_autobind = 1;
 468         if (args->flags & RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT)
 469                 clnt->cl_noretranstimeo = 1;
 470         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 471                 clnt->cl_discrtry = 1;
 472         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 473                 clnt->cl_chatty = 1;
 474
 475         return clnt;
 476 }
 477 EXPORT_SYMBOL_GPL(rpc_create_xprt);
 478
 479 /**
 480  * rpc_create - create an RPC client and transport with one call
 481  * @args: rpc_clnt create argument structure
 482  *
 483  * Creates and initializes an RPC transport and an RPC client.
 484  *
 485  * It can ping the server in order to determine if it is up, and to see if
 486  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 487  * this behavior so asynchronous tasks can also use rpc_create.
 488  */
 489 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 490 {
 491         struct rpc_xprt *xprt;
 492         struct xprt_create xprtargs = {
 493                 .net = args->net,
 494                 .ident = args->protocol,
 495                 .srcaddr = args->saddress,
 496                 .dstaddr = args->address,
 497                 .addrlen = args->addrsize,
 498                 .servername = args->servername,
 499                 .bc_xprt = args->bc_xprt,
 500         };
 501         char servername[48];
 502
 503         if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
 504                 xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
 505         if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
 506                 xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
 507         /*
 508          * If the caller chooses not to specify a hostname, whip
 509          * up a string representation of the passed-in address.
 510          */
 511         if (xprtargs.servername == NULL) {
 512                 struct sockaddr_un *sun =
 513                                 (struct sockaddr_un *)args->address;
 514                 struct sockaddr_in *sin =
 515                                 (struct sockaddr_in *)args->address;
 516                 struct sockaddr_in6 *sin6 =
 517                                 (struct sockaddr_in6 *)args->address;
 518
 519                 servername[0] = '\0';
 520                 switch (args->address->sa_family) {
 521                 case AF_LOCAL:
 522                         snprintf(servername, sizeof(servername), "%s",
 523                                  sun->sun_path);
 524                         break;
 525                 case AF_INET:
 526                         snprintf(servername, sizeof(servername), "%pI4",
 527                                  &sin->sin_addr.s_addr);
 528                         break;
 529                 case AF_INET6:
 530                         snprintf(servername, sizeof(servername), "%pI6",
 531                                  &sin6->sin6_addr);
 532                         break;
 533                 default:
 534                         /* caller wants default server name, but
 535                          * address family isn't recognized. */
 536                         return ERR_PTR(-EINVAL);
 537                 }
 538                 xprtargs.servername = servername;
 539         }
 540
 541         xprt = xprt_create_transport(&xprtargs);
 542         if (IS_ERR(xprt))
 543                 return (struct rpc_clnt *)xprt;
 544
 545         /*
 546          * By default, kernel RPC client connects from a reserved port.
 547          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 548          * but it is always enabled for rpciod, which handles the connect
 549          * operation.
 550          */
 551         xprt->resvport = 1;
 552         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 553                 xprt->resvport = 0;
 554
 555         return rpc_create_xprt(args, xprt);
 556 }
 557 EXPORT_SYMBOL_GPL(rpc_create);
 558
 559 /*
 560  * This function clones the RPC client structure. It allows us to share the
 561  * same transport while varying parameters such as the authentication
 562  * flavour.
 563  */
 564 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
 565                                            struct rpc_clnt *clnt)
 566 {
 567         struct rpc_xprt *xprt;
 568         struct rpc_clnt *new;
 569         int err;
 570
 571         err = -ENOMEM;
 572         rcu_read_lock();
 573         xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
 574         rcu_read_unlock();
 575         if (xprt == NULL)
 576                 goto out_err;
 577         args->servername = xprt->servername;
 578         args->nodename = clnt->cl_nodename;
 579
 580         new = rpc_new_client(args, xprt, clnt);
 581         if (IS_ERR(new)) {
 582                 err = PTR_ERR(new);
 583                 goto out_err;
 584         }
 585
 586         /* Turn off autobind on clones */
 587         new->cl_autobind = 0;
 588         new->cl_softrtry = clnt->cl_softrtry;
 589         new->cl_noretranstimeo = clnt->cl_noretranstimeo;
 590         new->cl_discrtry = clnt->cl_discrtry;
 591         new->cl_chatty = clnt->cl_chatty;
 592         return new;
 593
 594 out_err:
 595         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 596         return ERR_PTR(err);
 597 }
 598
 599 /**
 600  * rpc_clone_client - Clone an RPC client structure
 601  *
 602  * @clnt: RPC client whose parameters are copied
 603  *
 604  * Returns a fresh RPC client or an ERR_PTR.
 605  */
 606 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
 607 {
 608         struct rpc_create_args args = {
 609                 .program        = clnt->cl_program,
 610                 .prognumber     = clnt->cl_prog,
 611                 .version        = clnt->cl_vers,
 612                 .authflavor     = clnt->cl_auth->au_flavor,
 613         };
 614         return __rpc_clone_client(&args, clnt);
 615 }
 616 EXPORT_SYMBOL_GPL(rpc_clone_client);
 617
 618 /**
 619  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
 620  *
 621  * @clnt: RPC client whose parameters are copied
 622  * @flavor: security flavor for new client
 623  *
 624  * Returns a fresh RPC client or an ERR_PTR.
 625  */
 626 struct rpc_clnt *
 627 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 628 {
 629         struct rpc_create_args args = {
 630                 .program        = clnt->cl_program,
 631                 .prognumber     = clnt->cl_prog,
 632                 .version        = clnt->cl_vers,
 633                 .authflavor     = flavor,
 634         };
 635         return __rpc_clone_client(&args, clnt);
 636 }
 637 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
 638
 639 /**
 640  * rpc_switch_client_transport: switch the RPC transport on the fly
 641  * @clnt: pointer to a struct rpc_clnt
 642  * @args: pointer to the new transport arguments
 643  * @timeout: pointer to the new timeout parameters
 644  *
 645  * This function allows the caller to switch the RPC transport for the
 646  * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS
 647  * server, for instance.  It assumes that the caller has ensured that
 648  * there are no active RPC tasks by using some form of locking.
 649  *
 650  * Returns zero if "clnt" is now using the new xprt.  Otherwise a
 651  * negative errno is returned, and "clnt" continues to use the old
 652  * xprt.
 653  */
 654 int rpc_switch_client_transport(struct rpc_clnt *clnt,
 655                 struct xprt_create *args,
 656                 const struct rpc_timeout *timeout)
 657 {
 658         const struct rpc_timeout *old_timeo;
 659         rpc_authflavor_t pseudoflavor;
 660         struct rpc_xprt *xprt, *old;
 661         struct rpc_clnt *parent;
 662         int err;
 663
 664         xprt = xprt_create_transport(args);
 665         if (IS_ERR(xprt)) {
 666                 dprintk("RPC:       failed to create new xprt for clnt %p\n",
 667                         clnt);
 668                 return PTR_ERR(xprt);
 669         }
 670
 671         pseudoflavor = clnt->cl_auth->au_flavor;
 672
 673         old_timeo = clnt->cl_timeout;
 674         old = rpc_clnt_set_transport(clnt, xprt, timeout);
 675
 676         rpc_unregister_client(clnt);
 677         __rpc_clnt_remove_pipedir(clnt);
 678         rpc_clnt_debugfs_unregister(clnt);
 679
 680         /*
 681          * A new transport was created.  "clnt" therefore
 682          * becomes the root of a new cl_parent tree.  clnt's
 683          * children, if it has any, still point to the old xprt.
 684          */
 685         parent = clnt->cl_parent;
 686         clnt->cl_parent = clnt;
 687
 688         /*
 689          * The old rpc_auth cache cannot be re-used.  GSS
 690          * contexts in particular are between a single
 691          * client and server.
 692          */
 693         err = rpc_client_register(clnt, pseudoflavor, NULL);
 694         if (err)
 695                 goto out_revert;
 696
 697         synchronize_rcu();
 698         if (parent != clnt)
 699                 rpc_release_client(parent);
 700         xprt_put(old);
 701         dprintk("RPC:       replaced xprt for clnt %p\n", clnt);
 702         return 0;
 703
 704 out_revert:
 705         rpc_clnt_set_transport(clnt, old, old_timeo);
 706         clnt->cl_parent = parent;
 707         rpc_client_register(clnt, pseudoflavor, NULL);
 708         xprt_put(xprt);
 709         dprintk("RPC:       failed to switch xprt for clnt %p\n", clnt);
 710         return err;
 711 }
 712 EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
 713
 714 /*
 715  * Kill all tasks for the given client.
 716  * XXX: kill their descendants as well?
 717  */
 718 void rpc_killall_tasks(struct rpc_clnt *clnt)
 719 {
 720         struct rpc_task *rovr;
 721
 722
 723         if (list_empty(&clnt->cl_tasks))
 724                 return;
 725         dprintk("RPC:       killing all tasks for client %p\n", clnt);
 726         /*
 727          * Spin lock all_tasks to prevent changes...
 728          */
 729         spin_lock(&clnt->cl_lock);
 730         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
 731                 if (!RPC_IS_ACTIVATED(rovr))
 732                         continue;
 733                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
 734                         rovr->tk_flags |= RPC_TASK_KILLED;
 735                         rpc_exit(rovr, -EIO);
 736                         if (RPC_IS_QUEUED(rovr))
 737                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
 738                                                         rovr);
 739                 }
 740         }
 741         spin_unlock(&clnt->cl_lock);
 742 }
 743 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 744
 745 /*
 746  * Properly shut down an RPC client, terminating all outstanding
 747  * requests.
 748  */
 749 void rpc_shutdown_client(struct rpc_clnt *clnt)
 750 {
 751         might_sleep();
 752
 753         dprintk_rcu("RPC:       shutting down %s client for %s\n",
 754                         clnt->cl_program->name,
 755                         rcu_dereference(clnt->cl_xprt)->servername);
 756
 757         while (!list_empty(&clnt->cl_tasks)) {
 758                 rpc_killall_tasks(clnt);
 759                 wait_event_timeout(destroy_wait,
 760                         list_empty(&clnt->cl_tasks), 1*HZ);
 761         }
 762
 763         rpc_release_client(clnt);
 764 }
 765 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 766
 767 /*
 768  * Free an RPC client
 769  */
 770 static struct rpc_clnt *
 771 rpc_free_client(struct rpc_clnt *clnt)
 772 {
 773         struct rpc_clnt *parent = NULL;
 774
 775         dprintk_rcu("RPC:       destroying %s client for %s\n",
 776                         clnt->cl_program->name,
 777                         rcu_dereference(clnt->cl_xprt)->servername);
 778         if (clnt->cl_parent != clnt)
 779                 parent = clnt->cl_parent;
 780         rpc_clnt_debugfs_unregister(clnt);
 781         rpc_clnt_remove_pipedir(clnt);
 782         rpc_unregister_client(clnt);
 783         rpc_free_iostats(clnt->cl_metrics);
 784         clnt->cl_metrics = NULL;
 785         xprt_put(rcu_dereference_raw(clnt->cl_xprt));
 786         rpciod_down();
 787         rpc_free_clid(clnt);
 788         kfree(clnt);
 789         return parent;
 790 }
 791
 792 /*
 793  * Free an RPC client
 794  */
 795 static struct rpc_clnt *
 796 rpc_free_auth(struct rpc_clnt *clnt)
 797 {
 798         if (clnt->cl_auth == NULL)
 799                 return rpc_free_client(clnt);
 800
 801         /*
 802          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 803          *       release remaining GSS contexts. This mechanism ensures
 804          *       that it can do so safely.
 805          */
 806         atomic_inc(&clnt->cl_count);
 807         rpcauth_release(clnt->cl_auth);
 808         clnt->cl_auth = NULL;
 809         if (atomic_dec_and_test(&clnt->cl_count))
 810                 return rpc_free_client(clnt);
 811         return NULL;
 812 }
 813
 814 /*
 815  * Release reference to the RPC client
 816  */
 817 void
 818 rpc_release_client(struct rpc_clnt *clnt)
 819 {
 820         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 821
 822         do {
 823                 if (list_empty(&clnt->cl_tasks))
 824                         wake_up(&destroy_wait);
 825                 if (!atomic_dec_and_test(&clnt->cl_count))
 826                         break;
 827                 clnt = rpc_free_auth(clnt);
 828         } while (clnt != NULL);
 829 }
 830 EXPORT_SYMBOL_GPL(rpc_release_client);
 831
 832 /**
 833  * rpc_bind_new_program - bind a new RPC program to an existing client
 834  * @old: old rpc_client
 835  * @program: rpc program to set
 836  * @vers: rpc program version
 837  *
 838  * Clones the rpc client and sets up a new RPC program. This is mainly
 839  * of use for enabling different RPC programs to share the same transport.
 840  * The Sun NFSv2/v3 ACL protocol can do this.
 841  */
 842 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 843                                       const struct rpc_program *program,
 844                                       u32 vers)
 845 {
 846         struct rpc_create_args args = {
 847                 .program        = program,
 848                 .prognumber     = program->number,
 849                 .version        = vers,
 850                 .authflavor     = old->cl_auth->au_flavor,
 851         };
 852         struct rpc_clnt *clnt;
 853         int err;
 854
 855         clnt = __rpc_clone_client(&args, old);
 856         if (IS_ERR(clnt))
 857                 goto out;
 858         err = rpc_ping(clnt);
 859         if (err != 0) {
 860                 rpc_shutdown_client(clnt);
 861                 clnt = ERR_PTR(err);
 862         }
 863 out:
 864         return clnt;
 865 }
 866 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 867
 868 void rpc_task_release_client(struct rpc_task *task)
 869 {
 870         struct rpc_clnt *clnt = task->tk_client;
 871
 872         if (clnt != NULL) {
 873                 /* Remove from client task list */
 874                 spin_lock(&clnt->cl_lock);
 875                 list_del(&task->tk_task);
 876                 spin_unlock(&clnt->cl_lock);
 877                 task->tk_client = NULL;
 878
 879                 rpc_release_client(clnt);
 880         }
 881 }
 882
 883 static
 884 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 885 {
 886         if (clnt != NULL) {
 887                 rpc_task_release_client(task);
 888                 task->tk_client = clnt;
 889                 atomic_inc(&clnt->cl_count);
 890                 if (clnt->cl_softrtry)
 891                         task->tk_flags |= RPC_TASK_SOFT;
 892                 if (clnt->cl_noretranstimeo)
 893                         task->tk_flags |= RPC_TASK_NO_RETRANS_TIMEOUT;
 894                 if (sk_memalloc_socks()) {
 895                         struct rpc_xprt *xprt;
 896
 897                         rcu_read_lock();
 898                         xprt = rcu_dereference(clnt->cl_xprt);
 899                         if (xprt->swapper)
 900                                 task->tk_flags |= RPC_TASK_SWAPPER;
 901                         rcu_read_unlock();
 902                 }
 903                 /* Add to the client's list of all tasks */
 904                 spin_lock(&clnt->cl_lock);
 905                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 906                 spin_unlock(&clnt->cl_lock);
 907         }
 908 }
 909
 910 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 911 {
 912         rpc_task_release_client(task);
 913         rpc_task_set_client(task, clnt);
 914 }
 915 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 916
 917
 918 static void
 919 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 920 {
 921         if (msg != NULL) {
 922                 task->tk_msg.rpc_proc = msg->rpc_proc;
 923                 task->tk_msg.rpc_argp = msg->rpc_argp;
 924                 task->tk_msg.rpc_resp = msg->rpc_resp;
 925                 if (msg->rpc_cred != NULL)
 926                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 927         }
 928 }
 929
 930 /*
 931  * Default callback for async RPC calls
 932  */
 933 static void
 934 rpc_default_callback(struct rpc_task *task, void *data)
 935 {
 936 }
 937
 938 static const struct rpc_call_ops rpc_default_ops = {
 939         .rpc_call_done = rpc_default_callback,
 940 };
 941
 942 /**
 943  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 944  * @task_setup_data: pointer to task initialisation data
 945  */
 946 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 947 {
 948         struct rpc_task *task;
 949
 950         task = rpc_new_task(task_setup_data);
 951         if (IS_ERR(task))
 952                 goto out;
 953
 954         rpc_task_set_client(task, task_setup_data->rpc_client);
 955         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 956
 957         if (task->tk_action == NULL)
 958                 rpc_call_start(task);
 959
 960         atomic_inc(&task->tk_count);
 961         rpc_execute(task);
 962 out:
 963         return task;
 964 }
 965 EXPORT_SYMBOL_GPL(rpc_run_task);
 966
 967 /**
 968  * rpc_call_sync - Perform a synchronous RPC call
 969  * @clnt: pointer to RPC client
 970  * @msg: RPC call parameters
 971  * @flags: RPC call flags
 972  */
 973 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 974 {
 975         struct rpc_task *task;
 976         struct rpc_task_setup task_setup_data = {
 977                 .rpc_client = clnt,
 978                 .rpc_message = msg,
 979                 .callback_ops = &rpc_default_ops,
 980                 .flags = flags,
 981         };
 982         int status;
 983
 984         WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
 985         if (flags & RPC_TASK_ASYNC) {
 986                 rpc_release_calldata(task_setup_data.callback_ops,
 987                         task_setup_data.callback_data);
 988                 return -EINVAL;
 989         }
 990
 991         task = rpc_run_task(&task_setup_data);
 992         if (IS_ERR(task))
 993                 return PTR_ERR(task);
 994         status = task->tk_status;
 995         rpc_put_task(task);
 996         return status;
 997 }
 998 EXPORT_SYMBOL_GPL(rpc_call_sync);
 999
1000 /**
1001  * rpc_call_async - Perform an asynchronous RPC call
1002  * @clnt: pointer to RPC client
1003  * @msg: RPC call parameters
1004  * @flags: RPC call flags
1005  * @tk_ops: RPC call ops
1006  * @data: user call data
1007  */
1008 int
1009 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
1010                const struct rpc_call_ops *tk_ops, void *data)
1011 {
1012         struct rpc_task *task;
1013         struct rpc_task_setup task_setup_data = {
1014                 .rpc_client = clnt,
1015                 .rpc_message = msg,
1016                 .callback_ops = tk_ops,
1017                 .callback_data = data,
1018                 .flags = flags|RPC_TASK_ASYNC,
1019         };
1020
1021         task = rpc_run_task(&task_setup_data);
1022         if (IS_ERR(task))
1023                 return PTR_ERR(task);
1024         rpc_put_task(task);
1025         return 0;
1026 }
1027 EXPORT_SYMBOL_GPL(rpc_call_async);
1028
1029 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1030 /**
1031  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1032  * rpc_execute against it
1033  * @req: RPC request
1034  * @tk_ops: RPC call ops
1035  */
1036 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
1037                                 const struct rpc_call_ops *tk_ops)
1038 {
1039         struct rpc_task *task;
1040         struct xdr_buf *xbufp = &req->rq_snd_buf;
1041         struct rpc_task_setup task_setup_data = {
1042                 .callback_ops = tk_ops,
1043         };
1044
1045         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
1046         /*
1047          * Create an rpc_task to send the data
1048          */
1049         task = rpc_new_task(&task_setup_data);
1050         if (IS_ERR(task)) {
1051                 xprt_free_bc_request(req);
1052                 goto out;
1053         }
1054         task->tk_rqstp = req;
1055
1056         /*
1057          * Set up the xdr_buf length.
1058          * This also indicates that the buffer is XDR encoded already.
1059          */
1060         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
1061                         xbufp->tail[0].iov_len;
1062
1063         task->tk_action = call_bc_transmit;
1064         atomic_inc(&task->tk_count);
1065         WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
1066         rpc_execute(task);
1067
1068 out:
1069         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
1070         return task;
1071 }
1072 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1073
1074 void
1075 rpc_call_start(struct rpc_task *task)
1076 {
1077         task->tk_action = call_start;
1078 }
1079 EXPORT_SYMBOL_GPL(rpc_call_start);
1080
1081 /**
1082  * rpc_peeraddr - extract remote peer address from clnt's xprt
1083  * @clnt: RPC client structure
1084  * @buf: target buffer
1085  * @bufsize: length of target buffer
1086  *
1087  * Returns the number of bytes that are actually in the stored address.
1088  */
1089 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
1090 {
1091         size_t bytes;
1092         struct rpc_xprt *xprt;
1093
1094         rcu_read_lock();
1095         xprt = rcu_dereference(clnt->cl_xprt);
1096
1097         bytes = xprt->addrlen;
1098         if (bytes > bufsize)
1099                 bytes = bufsize;
1100         memcpy(buf, &xprt->addr, bytes);
1101         rcu_read_unlock();
1102
1103         return bytes;
1104 }
1105 EXPORT_SYMBOL_GPL(rpc_peeraddr);
1106
1107 /**
1108  * rpc_peeraddr2str - return remote peer address in printable format
1109  * @clnt: RPC client structure
1110  * @format: address format
1111  *
1112  * NB: the lifetime of the memory referenced by the returned pointer is
1113  * the same as the rpc_xprt itself.  As long as the caller uses this
1114  * pointer, it must hold the RCU read lock.
1115  */
1116 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
1117                              enum rpc_display_format_t format)
1118 {
1119         struct rpc_xprt *xprt;
1120
1121         xprt = rcu_dereference(clnt->cl_xprt);
1122
1123         if (xprt->address_strings[format] != NULL)
1124                 return xprt->address_strings[format];
1125         else
1126                 return "unprintable";
1127 }
1128 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
1129
1130 static const struct sockaddr_in rpc_inaddr_loopback = {
1131         .sin_family             = AF_INET,
1132         .sin_addr.s_addr        = htonl(INADDR_ANY),
1133 };
1134
1135 static const struct sockaddr_in6 rpc_in6addr_loopback = {
1136         .sin6_family            = AF_INET6,
1137         .sin6_addr              = IN6ADDR_ANY_INIT,
1138 };
1139
1140 /*
1141  * Try a getsockname() on a connected datagram socket.  Using a
1142  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1143  * This conserves the ephemeral port number space.
1144  *
1145  * Returns zero and fills in "buf" if successful; otherwise, a
1146  * negative errno is returned.
1147  */
1148 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1149                         struct sockaddr *buf, int buflen)
1150 {
1151         struct socket *sock;
1152         int err;
1153
1154         err = __sock_create(net, sap->sa_family,
1155                                 SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1156         if (err < 0) {
1157                 dprintk("RPC:       can't create UDP socket (%d)\n", err);
1158                 goto out;
1159         }
1160
1161         switch (sap->sa_family) {
1162         case AF_INET:
1163                 err = kernel_bind(sock,
1164                                 (struct sockaddr *)&rpc_inaddr_loopback,
1165                                 sizeof(rpc_inaddr_loopback));
1166                 break;
1167         case AF_INET6:
1168                 err = kernel_bind(sock,
1169                                 (struct sockaddr *)&rpc_in6addr_loopback,
1170                                 sizeof(rpc_in6addr_loopback));
1171                 break;
1172         default:
1173                 err = -EAFNOSUPPORT;
1174                 goto out;
1175         }
1176         if (err < 0) {
1177                 dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1178                 goto out_release;
1179         }
1180
1181         err = kernel_connect(sock, sap, salen, 0);
1182         if (err < 0) {
1183                 dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1184                 goto out_release;
1185         }
1186
1187         err = kernel_getsockname(sock, buf, &buflen);
1188         if (err < 0) {
1189                 dprintk("RPC:       getsockname failed (%d)\n", err);
1190                 goto out_release;
1191         }
1192
1193         err = 0;
1194         if (buf->sa_family == AF_INET6) {
1195                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1196                 sin6->sin6_scope_id = 0;
1197         }
1198         dprintk("RPC:       %s succeeded\n", __func__);
1199
1200 out_release:
1201         sock_release(sock);
1202 out:
1203         return err;
1204 }
1205
1206 /*
1207  * Scraping a connected socket failed, so we don't have a useable
1208  * local address.  Fallback: generate an address that will prevent
1209  * the server from calling us back.
1210  *
1211  * Returns zero and fills in "buf" if successful; otherwise, a
1212  * negative errno is returned.
1213  */
1214 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1215 {
1216         switch (family) {
1217         case AF_INET:
1218                 if (buflen < sizeof(rpc_inaddr_loopback))
1219                         return -EINVAL;
1220                 memcpy(buf, &rpc_inaddr_loopback,
1221                                 sizeof(rpc_inaddr_loopback));
1222                 break;
1223         case AF_INET6:
1224                 if (buflen < sizeof(rpc_in6addr_loopback))
1225                         return -EINVAL;
1226                 memcpy(buf, &rpc_in6addr_loopback,
1227                                 sizeof(rpc_in6addr_loopback));
1228         default:
1229                 dprintk("RPC:       %s: address family not supported\n",
1230                         __func__);
1231                 return -EAFNOSUPPORT;
1232         }
1233         dprintk("RPC:       %s: succeeded\n", __func__);
1234         return 0;
1235 }
1236
1237 /**
1238  * rpc_localaddr - discover local endpoint address for an RPC client
1239  * @clnt: RPC client structure
1240  * @buf: target buffer
1241  * @buflen: size of target buffer, in bytes
1242  *
1243  * Returns zero and fills in "buf" and "buflen" if successful;
1244  * otherwise, a negative errno is returned.
1245  *
1246  * This works even if the underlying transport is not currently connected,
1247  * or if the upper layer never previously provided a source address.
1248  *
1249  * The result of this function call is transient: multiple calls in
1250  * succession may give different results, depending on how local
1251  * networking configuration changes over time.
1252  */
1253 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1254 {
1255         struct sockaddr_storage address;
1256         struct sockaddr *sap = (struct sockaddr *)&address;
1257         struct rpc_xprt *xprt;
1258         struct net *net;
1259         size_t salen;
1260         int err;
1261
1262         rcu_read_lock();
1263         xprt = rcu_dereference(clnt->cl_xprt);
1264         salen = xprt->addrlen;
1265         memcpy(sap, &xprt->addr, salen);
1266         net = get_net(xprt->xprt_net);
1267         rcu_read_unlock();
1268
1269         rpc_set_port(sap, 0);
1270         err = rpc_sockname(net, sap, salen, buf, buflen);
1271         put_net(net);
1272         if (err != 0)
1273                 /* Couldn't discover local address, return ANYADDR */
1274                 return rpc_anyaddr(sap->sa_family, buf, buflen);
1275         return 0;
1276 }
1277 EXPORT_SYMBOL_GPL(rpc_localaddr);
1278
1279 void
1280 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1281 {
1282         struct rpc_xprt *xprt;
1283
1284         rcu_read_lock();
1285         xprt = rcu_dereference(clnt->cl_xprt);
1286         if (xprt->ops->set_buffer_size)
1287                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1288         rcu_read_unlock();
1289 }
1290 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1291
1292 /**
1293  * rpc_protocol - Get transport protocol number for an RPC client
1294  * @clnt: RPC client to query
1295  *
1296  */
1297 int rpc_protocol(struct rpc_clnt *clnt)
1298 {
1299         int protocol;
1300
1301         rcu_read_lock();
1302         protocol = rcu_dereference(clnt->cl_xprt)->prot;
1303         rcu_read_unlock();
1304         return protocol;
1305 }
1306 EXPORT_SYMBOL_GPL(rpc_protocol);
1307
1308 /**
1309  * rpc_net_ns - Get the network namespace for this RPC client
1310  * @clnt: RPC client to query
1311  *
1312  */
1313 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1314 {
1315         struct net *ret;
1316
1317         rcu_read_lock();
1318         ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1319         rcu_read_unlock();
1320         return ret;
1321 }
1322 EXPORT_SYMBOL_GPL(rpc_net_ns);
1323
1324 /**
1325  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1326  * @clnt: RPC client to query
1327  *
1328  * For stream transports, this is one RPC record fragment (see RFC
1329  * 1831), as we don't support multi-record requests yet.  For datagram
1330  * transports, this is the size of an IP packet minus the IP, UDP, and
1331  * RPC header sizes.
1332  */
1333 size_t rpc_max_payload(struct rpc_clnt *clnt)
1334 {
1335         size_t ret;
1336
1337         rcu_read_lock();
1338         ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1339         rcu_read_unlock();
1340         return ret;
1341 }
1342 EXPORT_SYMBOL_GPL(rpc_max_payload);
1343
1344 /**
1345  * rpc_get_timeout - Get timeout for transport in units of HZ
1346  * @clnt: RPC client to query
1347  */
1348 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1349 {
1350         unsigned long ret;
1351
1352         rcu_read_lock();
1353         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1354         rcu_read_unlock();
1355         return ret;
1356 }
1357 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1358
1359 /**
1360  * rpc_force_rebind - force transport to check that remote port is unchanged
1361  * @clnt: client to rebind
1362  *
1363  */
1364 void rpc_force_rebind(struct rpc_clnt *clnt)
1365 {
1366         if (clnt->cl_autobind) {
1367                 rcu_read_lock();
1368                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1369                 rcu_read_unlock();
1370         }
1371 }
1372 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1373
1374 /*
1375  * Restart an (async) RPC call from the call_prepare state.
1376  * Usually called from within the exit handler.
1377  */
1378 int
1379 rpc_restart_call_prepare(struct rpc_task *task)
1380 {
1381         if (RPC_ASSASSINATED(task))
1382                 return 0;
1383         task->tk_action = call_start;
1384         task->tk_status = 0;
1385         if (task->tk_ops->rpc_call_prepare != NULL)
1386                 task->tk_action = rpc_prepare_task;
1387         return 1;
1388 }
1389 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1390
1391 /*
1392  * Restart an (async) RPC call. Usually called from within the
1393  * exit handler.
1394  */
1395 int
1396 rpc_restart_call(struct rpc_task *task)
1397 {
1398         if (RPC_ASSASSINATED(task))
1399                 return 0;
1400         task->tk_action = call_start;
1401         task->tk_status = 0;
1402         return 1;
1403 }
1404 EXPORT_SYMBOL_GPL(rpc_restart_call);
1405
1406 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1407 const char
1408 *rpc_proc_name(const struct rpc_task *task)
1409 {
1410         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1411
1412         if (proc) {
1413                 if (proc->p_name)
1414                         return proc->p_name;
1415                 else
1416                         return "NULL";
1417         } else
1418                 return "no proc";
1419 }
1420 #endif
1421
1422 /*
1423  * 0.  Initial state
1424  *
1425  *     Other FSM states can be visited zero or more times, but
1426  *     this state is visited exactly once for each RPC.
1427  */
1428 static void
1429 call_start(struct rpc_task *task)
1430 {
1431         struct rpc_clnt *clnt = task->tk_client;
1432
1433         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1434                         clnt->cl_program->name, clnt->cl_vers,
1435                         rpc_proc_name(task),
1436                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1437
1438         /* Increment call count */
1439         task->tk_msg.rpc_proc->p_count++;
1440         clnt->cl_stats->rpccnt++;
1441         task->tk_action = call_reserve;
1442 }
1443
1444 /*
1445  * 1.   Reserve an RPC call slot
1446  */
1447 static void
1448 call_reserve(struct rpc_task *task)
1449 {
1450         dprint_status(task);
1451
1452         task->tk_status  = 0;
1453         task->tk_action  = call_reserveresult;
1454         xprt_reserve(task);
1455 }
1456
1457 static void call_retry_reserve(struct rpc_task *task);
1458
1459 /*
1460  * 1b.  Grok the result of xprt_reserve()
1461  */
1462 static void
1463 call_reserveresult(struct rpc_task *task)
1464 {
1465         int status = task->tk_status;
1466
1467         dprint_status(task);
1468
1469         /*
1470          * After a call to xprt_reserve(), we must have either
1471          * a request slot or else an error status.
1472          */
1473         task->tk_status = 0;
1474         if (status >= 0) {
1475                 if (task->tk_rqstp) {
1476                         task->tk_action = call_refresh;
1477                         return;
1478                 }
1479
1480                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1481                                 __func__, status);
1482                 rpc_exit(task, -EIO);
1483                 return;
1484         }
1485
1486         /*
1487          * Even though there was an error, we may have acquired
1488          * a request slot somehow.  Make sure not to leak it.
1489          */
1490         if (task->tk_rqstp) {
1491                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1492                                 __func__, status);
1493                 xprt_release(task);
1494         }
1495
1496         switch (status) {
1497         case -ENOMEM:
1498                 rpc_delay(task, HZ >> 2);
1499         case -EAGAIN:   /* woken up; retry */
1500                 task->tk_action = call_retry_reserve;
1501                 return;
1502         case -EIO:      /* probably a shutdown */
1503                 break;
1504         default:
1505                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1506                                 __func__, status);
1507                 break;
1508         }
1509         rpc_exit(task, status);
1510 }
1511
1512 /*
1513  * 1c.  Retry reserving an RPC call slot
1514  */
1515 static void
1516 call_retry_reserve(struct rpc_task *task)
1517 {
1518         dprint_status(task);
1519
1520         task->tk_status  = 0;
1521         task->tk_action  = call_reserveresult;
1522         xprt_retry_reserve(task);
1523 }
1524
1525 /*
1526  * 2.   Bind and/or refresh the credentials
1527  */
1528 static void
1529 call_refresh(struct rpc_task *task)
1530 {
1531         dprint_status(task);
1532
1533         task->tk_action = call_refreshresult;
1534         task->tk_status = 0;
1535         task->tk_client->cl_stats->rpcauthrefresh++;
1536         rpcauth_refreshcred(task);
1537 }
1538
1539 /*
1540  * 2a.  Process the results of a credential refresh
1541  */
1542 static void
1543 call_refreshresult(struct rpc_task *task)
1544 {
1545         int status = task->tk_status;
1546
1547         dprint_status(task);
1548
1549         task->tk_status = 0;
1550         task->tk_action = call_refresh;
1551         switch (status) {
1552         case 0:
1553                 if (rpcauth_uptodatecred(task)) {
1554                         task->tk_action = call_allocate;
1555                         return;
1556                 }
1557                 /* Use rate-limiting and a max number of retries if refresh
1558                  * had status 0 but failed to update the cred.
1559                  */
1560         case -ETIMEDOUT:
1561                 rpc_delay(task, 3*HZ);
1562         case -EAGAIN:
1563                 status = -EACCES;
1564         case -EKEYEXPIRED:
1565                 if (!task->tk_cred_retry)
1566                         break;
1567                 task->tk_cred_retry--;
1568                 dprintk("RPC: %5u %s: retry refresh creds\n",
1569                                 task->tk_pid, __func__);
1570                 return;
1571         }
1572         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1573                                 task->tk_pid, __func__, status);
1574         rpc_exit(task, status);
1575 }
1576
1577 /*
1578  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1579  *      (Note: buffer memory is freed in xprt_release).
1580  */
1581 static void
1582 call_allocate(struct rpc_task *task)
1583 {
1584         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1585         struct rpc_rqst *req = task->tk_rqstp;
1586         struct rpc_xprt *xprt = req->rq_xprt;
1587         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1588
1589         dprint_status(task);
1590
1591         task->tk_status = 0;
1592         task->tk_action = call_bind;
1593
1594         if (req->rq_buffer)
1595                 return;
1596
1597         if (proc->p_proc != 0) {
1598                 BUG_ON(proc->p_arglen == 0);
1599                 if (proc->p_decode != NULL)
1600                         BUG_ON(proc->p_replen == 0);
1601         }
1602
1603         /*
1604          * Calculate the size (in quads) of the RPC call
1605          * and reply headers, and convert both values
1606          * to byte sizes.
1607          */
1608         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1609         req->rq_callsize <<= 2;
1610         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1611         req->rq_rcvsize <<= 2;
1612
1613         req->rq_buffer = xprt->ops->buf_alloc(task,
1614                                         req->rq_callsize + req->rq_rcvsize);
1615         if (req->rq_buffer != NULL)
1616                 return;
1617
1618         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1619
1620         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1621                 task->tk_action = call_allocate;
1622                 rpc_delay(task, HZ>>4);
1623                 return;
1624         }
1625
1626         rpc_exit(task, -ERESTARTSYS);
1627 }
1628
1629 static inline int
1630 rpc_task_need_encode(struct rpc_task *task)
1631 {
1632         return task->tk_rqstp->rq_snd_buf.len == 0;
1633 }
1634
1635 static inline void
1636 rpc_task_force_reencode(struct rpc_task *task)
1637 {
1638         task->tk_rqstp->rq_snd_buf.len = 0;
1639         task->tk_rqstp->rq_bytes_sent = 0;
1640 }
1641
1642 static inline void
1643 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1644 {
1645         buf->head[0].iov_base = start;
1646         buf->head[0].iov_len = len;
1647         buf->tail[0].iov_len = 0;
1648         buf->page_len = 0;
1649         buf->flags = 0;
1650         buf->len = 0;
1651         buf->buflen = len;
1652 }
1653
1654 /*
1655  * 3.   Encode arguments of an RPC call
1656  */
1657 static void
1658 rpc_xdr_encode(struct rpc_task *task)
1659 {
1660         struct rpc_rqst *req = task->tk_rqstp;
1661         kxdreproc_t     encode;
1662         __be32          *p;
1663
1664         dprint_status(task);
1665
1666         rpc_xdr_buf_init(&req->rq_snd_buf,
1667                          req->rq_buffer,
1668                          req->rq_callsize);
1669         rpc_xdr_buf_init(&req->rq_rcv_buf,
1670                          (char *)req->rq_buffer + req->rq_callsize,
1671                          req->rq_rcvsize);
1672
1673         p = rpc_encode_header(task);
1674         if (p == NULL) {
1675                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1676                 rpc_exit(task, -EIO);
1677                 return;
1678         }
1679
1680         encode = task->tk_msg.rpc_proc->p_encode;
1681         if (encode == NULL)
1682                 return;
1683
1684         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1685                         task->tk_msg.rpc_argp);
1686 }
1687
1688 /*
1689  * 4.   Get the server port number if not yet set
1690  */
1691 static void
1692 call_bind(struct rpc_task *task)
1693 {
1694         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1695
1696         dprint_status(task);
1697
1698         task->tk_action = call_connect;
1699         if (!xprt_bound(xprt)) {
1700                 task->tk_action = call_bind_status;
1701                 task->tk_timeout = xprt->bind_timeout;
1702                 xprt->ops->rpcbind(task);
1703         }
1704 }
1705
1706 /*
1707  * 4a.  Sort out bind result
1708  */
1709 static void
1710 call_bind_status(struct rpc_task *task)
1711 {
1712         int status = -EIO;
1713
1714         if (task->tk_status >= 0) {
1715                 dprint_status(task);
1716                 task->tk_status = 0;
1717                 task->tk_action = call_connect;
1718                 return;
1719         }
1720
1721         trace_rpc_bind_status(task);
1722         switch (task->tk_status) {
1723         case -ENOMEM:
1724                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1725                 rpc_delay(task, HZ >> 2);
1726                 goto retry_timeout;
1727         case -EACCES:
1728                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1729                                 "unavailable\n", task->tk_pid);
1730                 /* fail immediately if this is an RPC ping */
1731                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1732                         status = -EOPNOTSUPP;
1733                         break;
1734                 }
1735                 if (task->tk_rebind_retry == 0)
1736                         break;
1737                 task->tk_rebind_retry--;
1738                 rpc_delay(task, 3*HZ);
1739                 goto retry_timeout;
1740         case -ETIMEDOUT:
1741                 dprintk("RPC: %5u rpcbind request timed out\n",
1742                                 task->tk_pid);
1743                 goto retry_timeout;
1744         case -EPFNOSUPPORT:
1745                 /* server doesn't support any rpcbind version we know of */
1746                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1747                                 task->tk_pid);
1748                 break;
1749         case -EPROTONOSUPPORT:
1750                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1751                                 task->tk_pid);
1752                 goto retry_timeout;
1753         case -ECONNREFUSED:             /* connection problems */
1754         case -ECONNRESET:
1755         case -ECONNABORTED:
1756         case -ENOTCONN:
1757         case -EHOSTDOWN:
1758         case -EHOSTUNREACH:
1759         case -ENETUNREACH:
1760         case -ENOBUFS:
1761         case -EPIPE:
1762                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1763                                 task->tk_pid, task->tk_status);
1764                 if (!RPC_IS_SOFTCONN(task)) {
1765                         rpc_delay(task, 5*HZ);
1766                         goto retry_timeout;
1767                 }
1768                 status = task->tk_status;
1769                 break;
1770         default:
1771                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1772                                 task->tk_pid, -task->tk_status);
1773         }
1774
1775         rpc_exit(task, status);
1776         return;
1777
1778 retry_timeout:
1779         task->tk_status = 0;
1780         task->tk_action = call_timeout;
1781 }
1782
1783 /*
1784  * 4b.  Connect to the RPC server
1785  */
1786 static void
1787 call_connect(struct rpc_task *task)
1788 {
1789         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1790
1791         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1792                         task->tk_pid, xprt,
1793                         (xprt_connected(xprt) ? "is" : "is not"));
1794
1795         task->tk_action = call_transmit;
1796         if (!xprt_connected(xprt)) {
1797                 task->tk_action = call_connect_status;
1798                 if (task->tk_status < 0)
1799                         return;
1800                 if (task->tk_flags & RPC_TASK_NOCONNECT) {
1801                         rpc_exit(task, -ENOTCONN);
1802                         return;
1803                 }
1804                 xprt_connect(task);
1805         }
1806 }
1807
1808 /*
1809  * 4c.  Sort out connect result
1810  */
1811 static void
1812 call_connect_status(struct rpc_task *task)
1813 {
1814         struct rpc_clnt *clnt = task->tk_client;
1815         int status = task->tk_status;
1816
1817         dprint_status(task);
1818
1819         trace_rpc_connect_status(task, status);
1820         task->tk_status = 0;
1821         switch (status) {
1822         case -ECONNREFUSED:
1823         case -ECONNRESET:
1824         case -ECONNABORTED:
1825         case -ENETUNREACH:
1826         case -EHOSTUNREACH:
1827         case -EADDRINUSE:
1828         case -ENOBUFS:
1829         case -EPIPE:
1830                 if (RPC_IS_SOFTCONN(task))
1831                         break;
1832                 /* retry with existing socket, after a delay */
1833                 rpc_delay(task, 3*HZ);
1834         case -EAGAIN:
1835                 /* Check for timeouts before looping back to call_bind */
1836         case -ETIMEDOUT:
1837                 task->tk_action = call_timeout;
1838                 return;
1839         case 0:
1840                 clnt->cl_stats->netreconn++;
1841                 task->tk_action = call_transmit;
1842                 return;
1843         }
1844         rpc_exit(task, status);
1845 }
1846
1847 /*
1848  * 5.   Transmit the RPC request, and wait for reply
1849  */
1850 static void
1851 call_transmit(struct rpc_task *task)
1852 {
1853         int is_retrans = RPC_WAS_SENT(task);
1854
1855         dprint_status(task);
1856
1857         task->tk_action = call_status;
1858         if (task->tk_status < 0)
1859                 return;
1860         if (!xprt_prepare_transmit(task))
1861                 return;
1862         task->tk_action = call_transmit_status;
1863         /* Encode here so that rpcsec_gss can use correct sequence number. */
1864         if (rpc_task_need_encode(task)) {
1865                 rpc_xdr_encode(task);
1866                 /* Did the encode result in an error condition? */
1867                 if (task->tk_status != 0) {
1868                         /* Was the error nonfatal? */
1869                         if (task->tk_status == -EAGAIN)
1870                                 rpc_delay(task, HZ >> 4);
1871                         else
1872                                 rpc_exit(task, task->tk_status);
1873                         return;
1874                 }
1875         }
1876         xprt_transmit(task);
1877         if (task->tk_status < 0)
1878                 return;
1879         if (is_retrans)
1880                 task->tk_client->cl_stats->rpcretrans++;
1881         /*
1882          * On success, ensure that we call xprt_end_transmit() before sleeping
1883          * in order to allow access to the socket to other RPC requests.
1884          */
1885         call_transmit_status(task);
1886         if (rpc_reply_expected(task))
1887                 return;
1888         task->tk_action = rpc_exit_task;
1889         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1890 }
1891
1892 /*
1893  * 5a.  Handle cleanup after a transmission
1894  */
1895 static void
1896 call_transmit_status(struct rpc_task *task)
1897 {
1898         task->tk_action = call_status;
1899
1900         /*
1901          * Common case: success.  Force the compiler to put this
1902          * test first.
1903          */
1904         if (task->tk_status == 0) {
1905                 xprt_end_transmit(task);
1906                 rpc_task_force_reencode(task);
1907                 return;
1908         }
1909
1910         switch (task->tk_status) {
1911         case -EAGAIN:
1912                 break;
1913         default:
1914                 dprint_status(task);
1915                 xprt_end_transmit(task);
1916                 rpc_task_force_reencode(task);
1917                 break;
1918                 /*
1919                  * Special cases: if we've been waiting on the
1920                  * socket's write_space() callback, or if the
1921                  * socket just returned a connection error,
1922                  * then hold onto the transport lock.
1923                  */
1924         case -ECONNREFUSED:
1925         case -EHOSTDOWN:
1926         case -EHOSTUNREACH:
1927         case -ENETUNREACH:
1928         case -EPERM:
1929                 if (RPC_IS_SOFTCONN(task)) {
1930                         xprt_end_transmit(task);
1931                         rpc_exit(task, task->tk_status);
1932                         break;
1933                 }
1934         case -ECONNRESET:
1935         case -ECONNABORTED:
1936         case -EADDRINUSE:
1937         case -ENOTCONN:
1938         case -ENOBUFS:
1939         case -EPIPE:
1940                 rpc_task_force_reencode(task);
1941         }
1942 }
1943
1944 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1945 /*
1946  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1947  * addition, disconnect on connectivity errors.
1948  */
1949 static void
1950 call_bc_transmit(struct rpc_task *task)
1951 {
1952         struct rpc_rqst *req = task->tk_rqstp;
1953
1954         if (!xprt_prepare_transmit(task)) {
1955                 /*
1956                  * Could not reserve the transport. Try again after the
1957                  * transport is released.
1958                  */
1959                 task->tk_status = 0;
1960                 task->tk_action = call_bc_transmit;
1961                 return;
1962         }
1963
1964         task->tk_action = rpc_exit_task;
1965         if (task->tk_status < 0) {
1966                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1967                         "error: %d\n", task->tk_status);
1968                 return;
1969         }
1970
1971         xprt_transmit(task);
1972         xprt_end_transmit(task);
1973         dprint_status(task);
1974         switch (task->tk_status) {
1975         case 0:
1976                 /* Success */
1977                 break;
1978         case -EHOSTDOWN:
1979         case -EHOSTUNREACH:
1980         case -ENETUNREACH:
1981         case -ETIMEDOUT:
1982                 /*
1983                  * Problem reaching the server.  Disconnect and let the
1984                  * forechannel reestablish the connection.  The server will
1985                  * have to retransmit the backchannel request and we'll
1986                  * reprocess it.  Since these ops are idempotent, there's no
1987                  * need to cache our reply at this time.
1988                  */
1989                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1990                         "error: %d\n", task->tk_status);
1991                 xprt_conditional_disconnect(req->rq_xprt,
1992                         req->rq_connect_cookie);
1993                 break;
1994         default:
1995                 /*
1996                  * We were unable to reply and will have to drop the
1997                  * request.  The server should reconnect and retransmit.
1998                  */
1999                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
2000                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2001                         "error: %d\n", task->tk_status);
2002                 break;
2003         }
2004         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
2005 }
2006 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
2007
2008 /*
2009  * 6.   Sort out the RPC call status
2010  */
2011 static void
2012 call_status(struct rpc_task *task)
2013 {
2014         struct rpc_clnt *clnt = task->tk_client;
2015         struct rpc_rqst *req = task->tk_rqstp;
2016         int             status;
2017
2018         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
2019                 task->tk_status = req->rq_reply_bytes_recvd;
2020
2021         dprint_status(task);
2022
2023         status = task->tk_status;
2024         if (status >= 0) {
2025                 task->tk_action = call_decode;
2026                 return;
2027         }
2028
2029         trace_rpc_call_status(task);
2030         task->tk_status = 0;
2031         switch(status) {
2032         case -EHOSTDOWN:
2033         case -EHOSTUNREACH:
2034         case -ENETUNREACH:
2035         case -EPERM:
2036                 if (RPC_IS_SOFTCONN(task)) {
2037                         rpc_exit(task, status);
2038                         break;
2039                 }
2040                 /*
2041                  * Delay any retries for 3 seconds, then handle as if it
2042                  * were a timeout.
2043                  */
2044                 rpc_delay(task, 3*HZ);
2045         case -ETIMEDOUT:
2046                 task->tk_action = call_timeout;
2047                 if (!(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
2048                     && task->tk_client->cl_discrtry)
2049                         xprt_conditional_disconnect(req->rq_xprt,
2050                                         req->rq_connect_cookie);
2051                 break;
2052         case -ECONNREFUSED:
2053         case -ECONNRESET:
2054         case -ECONNABORTED:
2055                 rpc_force_rebind(clnt);
2056         case -EADDRINUSE:
2057         case -ENOBUFS:
2058                 rpc_delay(task, 3*HZ);
2059         case -EPIPE:
2060         case -ENOTCONN:
2061                 task->tk_action = call_bind;
2062                 break;
2063         case -EAGAIN:
2064                 task->tk_action = call_transmit;
2065                 break;
2066         case -EIO:
2067                 /* shutdown or soft timeout */
2068                 rpc_exit(task, status);
2069                 break;
2070         default:
2071                 if (clnt->cl_chatty)
2072                         printk("%s: RPC call returned error %d\n",
2073                                clnt->cl_program->name, -status);
2074                 rpc_exit(task, status);
2075         }
2076 }
2077
2078 /*
2079  * 6a.  Handle RPC timeout
2080  *      We do not release the request slot, so we keep using the
2081  *      same XID for all retransmits.
2082  */
2083 static void
2084 call_timeout(struct rpc_task *task)
2085 {
2086         struct rpc_clnt *clnt = task->tk_client;
2087
2088         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
2089                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
2090                 goto retry;
2091         }
2092
2093         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
2094         task->tk_timeouts++;
2095
2096         if (RPC_IS_SOFTCONN(task)) {
2097                 rpc_exit(task, -ETIMEDOUT);
2098                 return;
2099         }
2100         if (RPC_IS_SOFT(task)) {
2101                 if (clnt->cl_chatty) {
2102                         rcu_read_lock();
2103                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
2104                                 clnt->cl_program->name,
2105                                 rcu_dereference(clnt->cl_xprt)->servername);
2106                         rcu_read_unlock();
2107                 }
2108                 if (task->tk_flags & RPC_TASK_TIMEOUT)
2109                         rpc_exit(task, -ETIMEDOUT);
2110                 else
2111                         rpc_exit(task, -EIO);
2112                 return;
2113         }
2114
2115         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2116                 task->tk_flags |= RPC_CALL_MAJORSEEN;
2117                 if (clnt->cl_chatty) {
2118                         rcu_read_lock();
2119                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
2120                         clnt->cl_program->name,
2121                         rcu_dereference(clnt->cl_xprt)->servername);
2122                         rcu_read_unlock();
2123                 }
2124         }
2125         rpc_force_rebind(clnt);
2126         /*
2127          * Did our request time out due to an RPCSEC_GSS out-of-sequence
2128          * event? RFC2203 requires the server to drop all such requests.
2129          */
2130         rpcauth_invalcred(task);
2131
2132 retry:
2133         task->tk_action = call_bind;
2134         task->tk_status = 0;
2135 }
2136
2137 /*
2138  * 7.   Decode the RPC reply
2139  */
2140 static void
2141 call_decode(struct rpc_task *task)
2142 {
2143         struct rpc_clnt *clnt = task->tk_client;
2144         struct rpc_rqst *req = task->tk_rqstp;
2145         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
2146         __be32          *p;
2147
2148         dprint_status(task);
2149
2150         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2151                 if (clnt->cl_chatty) {
2152                         rcu_read_lock();
2153                         printk(KERN_NOTICE "%s: server %s OK\n",
2154                                 clnt->cl_program->name,
2155                                 rcu_dereference(clnt->cl_xprt)->servername);
2156                         rcu_read_unlock();
2157                 }
2158                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2159         }
2160
2161         /*
2162          * Ensure that we see all writes made by xprt_complete_rqst()
2163          * before it changed req->rq_reply_bytes_recvd.
2164          */
2165         smp_rmb();
2166         req->rq_rcv_buf.len = req->rq_private_buf.len;
2167
2168         /* Check that the softirq receive buffer is valid */
2169         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2170                                 sizeof(req->rq_rcv_buf)) != 0);
2171
2172         if (req->rq_rcv_buf.len < 12) {
2173                 if (!RPC_IS_SOFT(task)) {
2174                         task->tk_action = call_bind;
2175                         goto out_retry;
2176                 }
2177                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2178                                 clnt->cl_program->name, task->tk_status);
2179                 task->tk_action = call_timeout;
2180                 goto out_retry;
2181         }
2182
2183         p = rpc_verify_header(task);
2184         if (IS_ERR(p)) {
2185                 if (p == ERR_PTR(-EAGAIN))
2186                         goto out_retry;
2187                 return;
2188         }
2189
2190         task->tk_action = rpc_exit_task;
2191
2192         if (decode) {
2193                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2194                                                       task->tk_msg.rpc_resp);
2195         }
2196         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2197                         task->tk_status);
2198         return;
2199 out_retry:
2200         task->tk_status = 0;
2201         /* Note: rpc_verify_header() may have freed the RPC slot */
2202         if (task->tk_rqstp == req) {
2203                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2204                 if (task->tk_client->cl_discrtry)
2205                         xprt_conditional_disconnect(req->rq_xprt,
2206                                         req->rq_connect_cookie);
2207         }
2208 }
2209
2210 static __be32 *
2211 rpc_encode_header(struct rpc_task *task)
2212 {
2213         struct rpc_clnt *clnt = task->tk_client;
2214         struct rpc_rqst *req = task->tk_rqstp;
2215         __be32          *p = req->rq_svec[0].iov_base;
2216
2217         /* FIXME: check buffer size? */
2218
2219         p = xprt_skip_transport_header(req->rq_xprt, p);
2220         *p++ = req->rq_xid;             /* XID */
2221         *p++ = htonl(RPC_CALL);         /* CALL */
2222         *p++ = htonl(RPC_VERSION);      /* RPC version */
2223         *p++ = htonl(clnt->cl_prog);    /* program number */
2224         *p++ = htonl(clnt->cl_vers);    /* program version */
2225         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2226         p = rpcauth_marshcred(task, p);
2227         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2228         return p;
2229 }
2230
2231 static __be32 *
2232 rpc_verify_header(struct rpc_task *task)
2233 {
2234         struct rpc_clnt *clnt = task->tk_client;
2235         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2236         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2237         __be32  *p = iov->iov_base;
2238         u32 n;
2239         int error = -EACCES;
2240
2241         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2242                 /* RFC-1014 says that the representation of XDR data must be a
2243                  * multiple of four bytes
2244                  * - if it isn't pointer subtraction in the NFS client may give
2245                  *   undefined results
2246                  */
2247                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2248                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2249                        task->tk_rqstp->rq_rcv_buf.len);
2250                 error = -EIO;
2251                 goto out_err;
2252         }
2253         if ((len -= 3) < 0)
2254                 goto out_overflow;
2255
2256         p += 1; /* skip XID */
2257         if ((n = ntohl(*p++)) != RPC_REPLY) {
2258                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2259                         task->tk_pid, __func__, n);
2260                 error = -EIO;
2261                 goto out_garbage;
2262         }
2263
2264         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2265                 if (--len < 0)
2266                         goto out_overflow;
2267                 switch ((n = ntohl(*p++))) {
2268                 case RPC_AUTH_ERROR:
2269                         break;
2270                 case RPC_MISMATCH:
2271                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2272                                 task->tk_pid, __func__);
2273                         error = -EPROTONOSUPPORT;
2274                         goto out_err;
2275                 default:
2276                         dprintk("RPC: %5u %s: RPC call rejected, "
2277                                 "unknown error: %x\n",
2278                                 task->tk_pid, __func__, n);
2279                         error = -EIO;
2280                         goto out_err;
2281                 }
2282                 if (--len < 0)
2283                         goto out_overflow;
2284                 switch ((n = ntohl(*p++))) {
2285                 case RPC_AUTH_REJECTEDCRED:
2286                 case RPC_AUTH_REJECTEDVERF:
2287                 case RPCSEC_GSS_CREDPROBLEM:
2288                 case RPCSEC_GSS_CTXPROBLEM:
2289                         if (!task->tk_cred_retry)
2290                                 break;
2291                         task->tk_cred_retry--;
2292                         dprintk("RPC: %5u %s: retry stale creds\n",
2293                                         task->tk_pid, __func__);
2294                         rpcauth_invalcred(task);
2295                         /* Ensure we obtain a new XID! */
2296                         xprt_release(task);
2297                         task->tk_action = call_reserve;
2298                         goto out_retry;
2299                 case RPC_AUTH_BADCRED:
2300                 case RPC_AUTH_BADVERF:
2301                         /* possibly garbled cred/verf? */
2302                         if (!task->tk_garb_retry)
2303                                 break;
2304                         task->tk_garb_retry--;
2305                         dprintk("RPC: %5u %s: retry garbled creds\n",
2306                                         task->tk_pid, __func__);
2307                         task->tk_action = call_bind;
2308                         goto out_retry;
2309                 case RPC_AUTH_TOOWEAK:
2310                         rcu_read_lock();
2311                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2312                                "authentication.\n",
2313                                rcu_dereference(clnt->cl_xprt)->servername);
2314                         rcu_read_unlock();
2315                         break;
2316                 default:
2317                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2318                                         task->tk_pid, __func__, n);
2319                         error = -EIO;
2320                 }
2321                 dprintk("RPC: %5u %s: call rejected %d\n",
2322                                 task->tk_pid, __func__, n);
2323                 goto out_err;
2324         }
2325         p = rpcauth_checkverf(task, p);
2326         if (IS_ERR(p)) {
2327                 error = PTR_ERR(p);
2328                 dprintk("RPC: %5u %s: auth check failed with %d\n",
2329                                 task->tk_pid, __func__, error);
2330                 goto out_garbage;               /* bad verifier, retry */
2331         }
2332         len = p - (__be32 *)iov->iov_base - 1;
2333         if (len < 0)
2334                 goto out_overflow;
2335         switch ((n = ntohl(*p++))) {
2336         case RPC_SUCCESS:
2337                 return p;
2338         case RPC_PROG_UNAVAIL:
2339                 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2340                                 "by server %s\n", task->tk_pid, __func__,
2341                                 (unsigned int)clnt->cl_prog,
2342                                 rcu_dereference(clnt->cl_xprt)->servername);
2343                 error = -EPFNOSUPPORT;
2344                 goto out_err;
2345         case RPC_PROG_MISMATCH:
2346                 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2347                                 "by server %s\n", task->tk_pid, __func__,
2348                                 (unsigned int)clnt->cl_prog,
2349                                 (unsigned int)clnt->cl_vers,
2350                                 rcu_dereference(clnt->cl_xprt)->servername);
2351                 error = -EPROTONOSUPPORT;
2352                 goto out_err;
2353         case RPC_PROC_UNAVAIL:
2354                 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2355                                 "version %u on server %s\n",
2356                                 task->tk_pid, __func__,
2357                                 rpc_proc_name(task),
2358                                 clnt->cl_prog, clnt->cl_vers,
2359                                 rcu_dereference(clnt->cl_xprt)->servername);
2360                 error = -EOPNOTSUPP;
2361                 goto out_err;
2362         case RPC_GARBAGE_ARGS:
2363                 dprintk("RPC: %5u %s: server saw garbage\n",
2364                                 task->tk_pid, __func__);
2365                 break;                  /* retry */
2366         default:
2367                 dprintk("RPC: %5u %s: server accept status: %x\n",
2368                                 task->tk_pid, __func__, n);
2369                 /* Also retry */
2370         }
2371
2372 out_garbage:
2373         clnt->cl_stats->rpcgarbage++;
2374         if (task->tk_garb_retry) {
2375                 task->tk_garb_retry--;
2376                 dprintk("RPC: %5u %s: retrying\n",
2377                                 task->tk_pid, __func__);
2378                 task->tk_action = call_bind;
2379 out_retry:
2380                 return ERR_PTR(-EAGAIN);
2381         }
2382 out_err:
2383         rpc_exit(task, error);
2384         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2385                         __func__, error);
2386         return ERR_PTR(error);
2387 out_overflow:
2388         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2389                         __func__);
2390         goto out_garbage;
2391 }
2392
2393 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2394 {
2395 }
2396
2397 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2398 {
2399         return 0;
2400 }
2401
2402 static struct rpc_procinfo rpcproc_null = {
2403         .p_encode = rpcproc_encode_null,
2404         .p_decode = rpcproc_decode_null,
2405 };
2406
2407 static int rpc_ping(struct rpc_clnt *clnt)
2408 {
2409         struct rpc_message msg = {
2410                 .rpc_proc = &rpcproc_null,
2411         };
2412         int err;
2413         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2414         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2415         put_rpccred(msg.rpc_cred);
2416         return err;
2417 }
2418
2419 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2420 {
2421         struct rpc_message msg = {
2422                 .rpc_proc = &rpcproc_null,
2423                 .rpc_cred = cred,
2424         };
2425         struct rpc_task_setup task_setup_data = {
2426                 .rpc_client = clnt,
2427                 .rpc_message = &msg,
2428                 .callback_ops = &rpc_default_ops,
2429                 .flags = flags,
2430         };
2431         return rpc_run_task(&task_setup_data);
2432 }
2433 EXPORT_SYMBOL_GPL(rpc_call_null);
2434
2435 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
2436 static void rpc_show_header(void)
2437 {
2438         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2439                 "-timeout ---ops--\n");
2440 }
2441
2442 static void rpc_show_task(const struct rpc_clnt *clnt,
2443                           const struct rpc_task *task)
2444 {
2445         const char *rpc_waitq = "none";
2446
2447         if (RPC_IS_QUEUED(task))
2448                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2449
2450         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2451                 task->tk_pid, task->tk_flags, task->tk_status,
2452                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2453                 clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
2454                 task->tk_action, rpc_waitq);
2455 }
2456
2457 void rpc_show_tasks(struct net *net)
2458 {
2459         struct rpc_clnt *clnt;
2460         struct rpc_task *task;
2461         int header = 0;
2462         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2463
2464         spin_lock(&sn->rpc_client_lock);
2465         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2466                 spin_lock(&clnt->cl_lock);
2467                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2468                         if (!header) {
2469                                 rpc_show_header();
2470                                 header++;
2471                         }
2472                         rpc_show_task(clnt, task);
2473                 }
2474                 spin_unlock(&clnt->cl_lock);
2475         }
2476         spin_unlock(&sn->rpc_client_lock);
2477 }
2478 #endif