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   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  *  NB: BSD uses a more intelligent approach to guessing when a request
  17  *  or reply has been lost by keeping the RTO estimate for each procedure.
  18  *  We currently make do with a constant timeout value.
  19  *
  20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  22  */
  23
  24 #include <asm/system.h>
  25
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/kallsyms.h>
  29 #include <linux/mm.h>
  30 #include <linux/slab.h>
  31 #include <linux/smp_lock.h>
  32 #include <linux/utsname.h>
  33 #include <linux/workqueue.h>
  34 #include <linux/in6.h>
  35
  36 #include <linux/sunrpc/clnt.h>
  37 #include <linux/sunrpc/rpc_pipe_fs.h>
  38 #include <linux/sunrpc/metrics.h>
  39
  40
  41 #ifdef RPC_DEBUG
  42 # define RPCDBG_FACILITY        RPCDBG_CALL
  43 #endif
  44
  45 #define dprint_status(t)                                        \
  46         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  47                         __func__, t->tk_status)
  48
  49 /*
  50  * All RPC clients are linked into this list
  51  */
  52 static LIST_HEAD(all_clients);
  53 static DEFINE_SPINLOCK(rpc_client_lock);
  54
  55 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  56
  57
  58 static void     call_start(struct rpc_task *task);
  59 static void     call_reserve(struct rpc_task *task);
  60 static void     call_reserveresult(struct rpc_task *task);
  61 static void     call_allocate(struct rpc_task *task);
  62 static void     call_decode(struct rpc_task *task);
  63 static void     call_bind(struct rpc_task *task);
  64 static void     call_bind_status(struct rpc_task *task);
  65 static void     call_transmit(struct rpc_task *task);
  66 static void     call_status(struct rpc_task *task);
  67 static void     call_transmit_status(struct rpc_task *task);
  68 static void     call_refresh(struct rpc_task *task);
  69 static void     call_refreshresult(struct rpc_task *task);
  70 static void     call_timeout(struct rpc_task *task);
  71 static void     call_connect(struct rpc_task *task);
  72 static void     call_connect_status(struct rpc_task *task);
  73
  74 static __be32   *rpc_encode_header(struct rpc_task *task);
  75 static __be32   *rpc_verify_header(struct rpc_task *task);
  76 static int      rpc_ping(struct rpc_clnt *clnt, int flags);
  77
  78 static void rpc_register_client(struct rpc_clnt *clnt)
  79 {
  80         spin_lock(&rpc_client_lock);
  81         list_add(&clnt->cl_clients, &all_clients);
  82         spin_unlock(&rpc_client_lock);
  83 }
  84
  85 static void rpc_unregister_client(struct rpc_clnt *clnt)
  86 {
  87         spin_lock(&rpc_client_lock);
  88         list_del(&clnt->cl_clients);
  89         spin_unlock(&rpc_client_lock);
  90 }
  91
  92 static int
  93 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  94 {
  95         static uint32_t clntid;
  96         int error;
  97
  98         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  99         clnt->cl_dentry = ERR_PTR(-ENOENT);
 100         if (dir_name == NULL)
 101                 return 0;
 102
 103         clnt->cl_vfsmnt = rpc_get_mount();
 104         if (IS_ERR(clnt->cl_vfsmnt))
 105                 return PTR_ERR(clnt->cl_vfsmnt);
 106
 107         for (;;) {
 108                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
 109                                 "%s/clnt%x", dir_name,
 110                                 (unsigned int)clntid++);
 111                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
 112                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
 113                 if (!IS_ERR(clnt->cl_dentry))
 114                         return 0;
 115                 error = PTR_ERR(clnt->cl_dentry);
 116                 if (error != -EEXIST) {
 117                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
 118                                         clnt->cl_pathname, error);
 119                         rpc_put_mount();
 120                         return error;
 121                 }
 122         }
 123 }
 124
 125 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
 126 {
 127         struct rpc_program      *program = args->program;
 128         struct rpc_version      *version;
 129         struct rpc_clnt         *clnt = NULL;
 130         struct rpc_auth         *auth;
 131         int err;
 132         size_t len;
 133
 134         /* sanity check the name before trying to print it */
 135         err = -EINVAL;
 136         len = strlen(args->servername);
 137         if (len > RPC_MAXNETNAMELEN)
 138                 goto out_no_rpciod;
 139         len++;
 140
 141         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 142                         program->name, args->servername, xprt);
 143
 144         err = rpciod_up();
 145         if (err)
 146                 goto out_no_rpciod;
 147         err = -EINVAL;
 148         if (!xprt)
 149                 goto out_no_xprt;
 150
 151         if (args->version >= program->nrvers)
 152                 goto out_err;
 153         version = program->version[args->version];
 154         if (version == NULL)
 155                 goto out_err;
 156
 157         err = -ENOMEM;
 158         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 159         if (!clnt)
 160                 goto out_err;
 161         clnt->cl_parent = clnt;
 162
 163         clnt->cl_server = clnt->cl_inline_name;
 164         if (len > sizeof(clnt->cl_inline_name)) {
 165                 char *buf = kmalloc(len, GFP_KERNEL);
 166                 if (buf != NULL)
 167                         clnt->cl_server = buf;
 168                 else
 169                         len = sizeof(clnt->cl_inline_name);
 170         }
 171         strlcpy(clnt->cl_server, args->servername, len);
 172
 173         clnt->cl_xprt     = xprt;
 174         clnt->cl_procinfo = version->procs;
 175         clnt->cl_maxproc  = version->nrprocs;
 176         clnt->cl_protname = program->name;
 177         clnt->cl_prog     = program->number;
 178         clnt->cl_vers     = version->number;
 179         clnt->cl_stats    = program->stats;
 180         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 181         err = -ENOMEM;
 182         if (clnt->cl_metrics == NULL)
 183                 goto out_no_stats;
 184         clnt->cl_program  = program;
 185         INIT_LIST_HEAD(&clnt->cl_tasks);
 186         spin_lock_init(&clnt->cl_lock);
 187
 188         if (!xprt_bound(clnt->cl_xprt))
 189                 clnt->cl_autobind = 1;
 190
 191         clnt->cl_timeout = xprt->timeout;
 192         if (args->timeout != NULL) {
 193                 memcpy(&clnt->cl_timeout_default, args->timeout,
 194                                 sizeof(clnt->cl_timeout_default));
 195                 clnt->cl_timeout = &clnt->cl_timeout_default;
 196         }
 197
 198         clnt->cl_rtt = &clnt->cl_rtt_default;
 199         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 200
 201         kref_init(&clnt->cl_kref);
 202
 203         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 204         if (err < 0)
 205                 goto out_no_path;
 206
 207         auth = rpcauth_create(args->authflavor, clnt);
 208         if (IS_ERR(auth)) {
 209                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 210                                 args->authflavor);
 211                 err = PTR_ERR(auth);
 212                 goto out_no_auth;
 213         }
 214
 215         /* save the nodename */
 216         clnt->cl_nodelen = strlen(utsname()->nodename);
 217         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 218                 clnt->cl_nodelen = UNX_MAXNODENAME;
 219         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 220         rpc_register_client(clnt);
 221         return clnt;
 222
 223 out_no_auth:
 224         if (!IS_ERR(clnt->cl_dentry)) {
 225                 rpc_rmdir(clnt->cl_dentry);
 226                 rpc_put_mount();
 227         }
 228 out_no_path:
 229         rpc_free_iostats(clnt->cl_metrics);
 230 out_no_stats:
 231         if (clnt->cl_server != clnt->cl_inline_name)
 232                 kfree(clnt->cl_server);
 233         kfree(clnt);
 234 out_err:
 235         xprt_put(xprt);
 236 out_no_xprt:
 237         rpciod_down();
 238 out_no_rpciod:
 239         return ERR_PTR(err);
 240 }
 241
 242 /*
 243  * rpc_create - create an RPC client and transport with one call
 244  * @args: rpc_clnt create argument structure
 245  *
 246  * Creates and initializes an RPC transport and an RPC client.
 247  *
 248  * It can ping the server in order to determine if it is up, and to see if
 249  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 250  * this behavior so asynchronous tasks can also use rpc_create.
 251  */
 252 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 253 {
 254         struct rpc_xprt *xprt;
 255         struct rpc_clnt *clnt;
 256         struct xprt_create xprtargs = {
 257                 .ident = args->protocol,
 258                 .srcaddr = args->saddress,
 259                 .dstaddr = args->address,
 260                 .addrlen = args->addrsize,
 261         };
 262         char servername[48];
 263
 264         /*
 265          * If the caller chooses not to specify a hostname, whip
 266          * up a string representation of the passed-in address.
 267          */
 268         if (args->servername == NULL) {
 269                 servername[0] = '\0';
 270                 switch (args->address->sa_family) {
 271                 case AF_INET: {
 272                         struct sockaddr_in *sin =
 273                                         (struct sockaddr_in *)args->address;
 274                         snprintf(servername, sizeof(servername), NIPQUAD_FMT,
 275                                  NIPQUAD(sin->sin_addr.s_addr));
 276                         break;
 277                 }
 278                 case AF_INET6: {
 279                         struct sockaddr_in6 *sin =
 280                                         (struct sockaddr_in6 *)args->address;
 281                         snprintf(servername, sizeof(servername), NIP6_FMT,
 282                                  NIP6(sin->sin6_addr));
 283                         break;
 284                 }
 285                 default:
 286                         /* caller wants default server name, but
 287                          * address family isn't recognized. */
 288                         return ERR_PTR(-EINVAL);
 289                 }
 290                 args->servername = servername;
 291         }
 292
 293         xprt = xprt_create_transport(&xprtargs);
 294         if (IS_ERR(xprt))
 295                 return (struct rpc_clnt *)xprt;
 296
 297         /*
 298          * By default, kernel RPC client connects from a reserved port.
 299          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 300          * but it is always enabled for rpciod, which handles the connect
 301          * operation.
 302          */
 303         xprt->resvport = 1;
 304         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 305                 xprt->resvport = 0;
 306
 307         clnt = rpc_new_client(args, xprt);
 308         if (IS_ERR(clnt))
 309                 return clnt;
 310
 311         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 312                 int err = rpc_ping(clnt, RPC_TASK_SOFT);
 313                 if (err != 0) {
 314                         rpc_shutdown_client(clnt);
 315                         return ERR_PTR(err);
 316                 }
 317         }
 318
 319         clnt->cl_softrtry = 1;
 320         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 321                 clnt->cl_softrtry = 0;
 322
 323         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 324                 clnt->cl_autobind = 1;
 325         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 326                 clnt->cl_discrtry = 1;
 327         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 328                 clnt->cl_chatty = 1;
 329
 330         return clnt;
 331 }
 332 EXPORT_SYMBOL_GPL(rpc_create);
 333
 334 /*
 335  * This function clones the RPC client structure. It allows us to share the
 336  * same transport while varying parameters such as the authentication
 337  * flavour.
 338  */
 339 struct rpc_clnt *
 340 rpc_clone_client(struct rpc_clnt *clnt)
 341 {
 342         struct rpc_clnt *new;
 343         int err = -ENOMEM;
 344
 345         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 346         if (!new)
 347                 goto out_no_clnt;
 348         new->cl_parent = clnt;
 349         /* Turn off autobind on clones */
 350         new->cl_autobind = 0;
 351         INIT_LIST_HEAD(&new->cl_tasks);
 352         spin_lock_init(&new->cl_lock);
 353         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);
 354         new->cl_metrics = rpc_alloc_iostats(clnt);
 355         if (new->cl_metrics == NULL)
 356                 goto out_no_stats;
 357         kref_init(&new->cl_kref);
 358         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 359         if (err != 0)
 360                 goto out_no_path;
 361         if (new->cl_auth)
 362                 atomic_inc(&new->cl_auth->au_count);
 363         xprt_get(clnt->cl_xprt);
 364         kref_get(&clnt->cl_kref);
 365         rpc_register_client(new);
 366         rpciod_up();
 367         return new;
 368 out_no_path:
 369         rpc_free_iostats(new->cl_metrics);
 370 out_no_stats:
 371         kfree(new);
 372 out_no_clnt:
 373         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 374         return ERR_PTR(err);
 375 }
 376 EXPORT_SYMBOL_GPL(rpc_clone_client);
 377
 378 /*
 379  * Properly shut down an RPC client, terminating all outstanding
 380  * requests.
 381  */
 382 void rpc_shutdown_client(struct rpc_clnt *clnt)
 383 {
 384         dprintk("RPC:       shutting down %s client for %s\n",
 385                         clnt->cl_protname, clnt->cl_server);
 386
 387         while (!list_empty(&clnt->cl_tasks)) {
 388                 rpc_killall_tasks(clnt);
 389                 wait_event_timeout(destroy_wait,
 390                         list_empty(&clnt->cl_tasks), 1*HZ);
 391         }
 392
 393         rpc_release_client(clnt);
 394 }
 395 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 396
 397 /*
 398  * Free an RPC client
 399  */
 400 static void
 401 rpc_free_client(struct kref *kref)
 402 {
 403         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 404
 405         dprintk("RPC:       destroying %s client for %s\n",
 406                         clnt->cl_protname, clnt->cl_server);
 407         if (!IS_ERR(clnt->cl_dentry)) {
 408                 rpc_rmdir(clnt->cl_dentry);
 409                 rpc_put_mount();
 410         }
 411         if (clnt->cl_parent != clnt) {
 412                 rpc_release_client(clnt->cl_parent);
 413                 goto out_free;
 414         }
 415         if (clnt->cl_server != clnt->cl_inline_name)
 416                 kfree(clnt->cl_server);
 417 out_free:
 418         rpc_unregister_client(clnt);
 419         rpc_free_iostats(clnt->cl_metrics);
 420         clnt->cl_metrics = NULL;
 421         xprt_put(clnt->cl_xprt);
 422         rpciod_down();
 423         kfree(clnt);
 424 }
 425
 426 /*
 427  * Free an RPC client
 428  */
 429 static void
 430 rpc_free_auth(struct kref *kref)
 431 {
 432         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 433
 434         if (clnt->cl_auth == NULL) {
 435                 rpc_free_client(kref);
 436                 return;
 437         }
 438
 439         /*
 440          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 441          *       release remaining GSS contexts. This mechanism ensures
 442          *       that it can do so safely.
 443          */
 444         kref_init(kref);
 445         rpcauth_release(clnt->cl_auth);
 446         clnt->cl_auth = NULL;
 447         kref_put(kref, rpc_free_client);
 448 }
 449
 450 /*
 451  * Release reference to the RPC client
 452  */
 453 void
 454 rpc_release_client(struct rpc_clnt *clnt)
 455 {
 456         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 457
 458         if (list_empty(&clnt->cl_tasks))
 459                 wake_up(&destroy_wait);
 460         kref_put(&clnt->cl_kref, rpc_free_auth);
 461 }
 462
 463 /**
 464  * rpc_bind_new_program - bind a new RPC program to an existing client
 465  * @old: old rpc_client
 466  * @program: rpc program to set
 467  * @vers: rpc program version
 468  *
 469  * Clones the rpc client and sets up a new RPC program. This is mainly
 470  * of use for enabling different RPC programs to share the same transport.
 471  * The Sun NFSv2/v3 ACL protocol can do this.
 472  */
 473 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 474                                       struct rpc_program *program,
 475                                       u32 vers)
 476 {
 477         struct rpc_clnt *clnt;
 478         struct rpc_version *version;
 479         int err;
 480
 481         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 482         version = program->version[vers];
 483         clnt = rpc_clone_client(old);
 484         if (IS_ERR(clnt))
 485                 goto out;
 486         clnt->cl_procinfo = version->procs;
 487         clnt->cl_maxproc  = version->nrprocs;
 488         clnt->cl_protname = program->name;
 489         clnt->cl_prog     = program->number;
 490         clnt->cl_vers     = version->number;
 491         clnt->cl_stats    = program->stats;
 492         err = rpc_ping(clnt, RPC_TASK_SOFT);
 493         if (err != 0) {
 494                 rpc_shutdown_client(clnt);
 495                 clnt = ERR_PTR(err);
 496         }
 497 out:
 498         return clnt;
 499 }
 500 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 501
 502 /*
 503  * Default callback for async RPC calls
 504  */
 505 static void
 506 rpc_default_callback(struct rpc_task *task, void *data)
 507 {
 508 }
 509
 510 static const struct rpc_call_ops rpc_default_ops = {
 511         .rpc_call_done = rpc_default_callback,
 512 };
 513
 514 /**
 515  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 516  * @task_setup_data: pointer to task initialisation data
 517  */
 518 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 519 {
 520         struct rpc_task *task, *ret;
 521
 522         task = rpc_new_task(task_setup_data);
 523         if (task == NULL) {
 524                 rpc_release_calldata(task_setup_data->callback_ops,
 525                                 task_setup_data->callback_data);
 526                 ret = ERR_PTR(-ENOMEM);
 527                 goto out;
 528         }
 529
 530         if (task->tk_status != 0) {
 531                 ret = ERR_PTR(task->tk_status);
 532                 rpc_put_task(task);
 533                 goto out;
 534         }
 535         atomic_inc(&task->tk_count);
 536         rpc_execute(task);
 537         ret = task;
 538 out:
 539         return ret;
 540 }
 541 EXPORT_SYMBOL_GPL(rpc_run_task);
 542
 543 /**
 544  * rpc_call_sync - Perform a synchronous RPC call
 545  * @clnt: pointer to RPC client
 546  * @msg: RPC call parameters
 547  * @flags: RPC call flags
 548  */
 549 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 550 {
 551         struct rpc_task *task;
 552         struct rpc_task_setup task_setup_data = {
 553                 .rpc_client = clnt,
 554                 .rpc_message = msg,
 555                 .callback_ops = &rpc_default_ops,
 556                 .flags = flags,
 557         };
 558         int status;
 559
 560         BUG_ON(flags & RPC_TASK_ASYNC);
 561
 562         task = rpc_run_task(&task_setup_data);
 563         if (IS_ERR(task))
 564                 return PTR_ERR(task);
 565         status = task->tk_status;
 566         rpc_put_task(task);
 567         return status;
 568 }
 569 EXPORT_SYMBOL_GPL(rpc_call_sync);
 570
 571 /**
 572  * rpc_call_async - Perform an asynchronous RPC call
 573  * @clnt: pointer to RPC client
 574  * @msg: RPC call parameters
 575  * @flags: RPC call flags
 576  * @tk_ops: RPC call ops
 577  * @data: user call data
 578  */
 579 int
 580 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
 581                const struct rpc_call_ops *tk_ops, void *data)
 582 {
 583         struct rpc_task *task;
 584         struct rpc_task_setup task_setup_data = {
 585                 .rpc_client = clnt,
 586                 .rpc_message = msg,
 587                 .callback_ops = tk_ops,
 588                 .callback_data = data,
 589                 .flags = flags|RPC_TASK_ASYNC,
 590         };
 591
 592         task = rpc_run_task(&task_setup_data);
 593         if (IS_ERR(task))
 594                 return PTR_ERR(task);
 595         rpc_put_task(task);
 596         return 0;
 597 }
 598 EXPORT_SYMBOL_GPL(rpc_call_async);
 599
 600 void
 601 rpc_call_start(struct rpc_task *task)
 602 {
 603         task->tk_action = call_start;
 604 }
 605 EXPORT_SYMBOL_GPL(rpc_call_start);
 606
 607 /**
 608  * rpc_peeraddr - extract remote peer address from clnt's xprt
 609  * @clnt: RPC client structure
 610  * @buf: target buffer
 611  * @bufsize: length of target buffer
 612  *
 613  * Returns the number of bytes that are actually in the stored address.
 614  */
 615 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 616 {
 617         size_t bytes;
 618         struct rpc_xprt *xprt = clnt->cl_xprt;
 619
 620         bytes = sizeof(xprt->addr);
 621         if (bytes > bufsize)
 622                 bytes = bufsize;
 623         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 624         return xprt->addrlen;
 625 }
 626 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 627
 628 /**
 629  * rpc_peeraddr2str - return remote peer address in printable format
 630  * @clnt: RPC client structure
 631  * @format: address format
 632  *
 633  */
 634 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
 635                              enum rpc_display_format_t format)
 636 {
 637         struct rpc_xprt *xprt = clnt->cl_xprt;
 638
 639         if (xprt->address_strings[format] != NULL)
 640                 return xprt->address_strings[format];
 641         else
 642                 return "unprintable";
 643 }
 644 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 645
 646 void
 647 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 648 {
 649         struct rpc_xprt *xprt = clnt->cl_xprt;
 650         if (xprt->ops->set_buffer_size)
 651                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 652 }
 653 EXPORT_SYMBOL_GPL(rpc_setbufsize);
 654
 655 /*
 656  * Return size of largest payload RPC client can support, in bytes
 657  *
 658  * For stream transports, this is one RPC record fragment (see RFC
 659  * 1831), as we don't support multi-record requests yet.  For datagram
 660  * transports, this is the size of an IP packet minus the IP, UDP, and
 661  * RPC header sizes.
 662  */
 663 size_t rpc_max_payload(struct rpc_clnt *clnt)
 664 {
 665         return clnt->cl_xprt->max_payload;
 666 }
 667 EXPORT_SYMBOL_GPL(rpc_max_payload);
 668
 669 /**
 670  * rpc_force_rebind - force transport to check that remote port is unchanged
 671  * @clnt: client to rebind
 672  *
 673  */
 674 void rpc_force_rebind(struct rpc_clnt *clnt)
 675 {
 676         if (clnt->cl_autobind)
 677                 xprt_clear_bound(clnt->cl_xprt);
 678 }
 679 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 680
 681 /*
 682  * Restart an (async) RPC call. Usually called from within the
 683  * exit handler.
 684  */
 685 void
 686 rpc_restart_call(struct rpc_task *task)
 687 {
 688         if (RPC_ASSASSINATED(task))
 689                 return;
 690
 691         task->tk_action = call_start;
 692 }
 693 EXPORT_SYMBOL_GPL(rpc_restart_call);
 694
 695 #ifdef RPC_DEBUG
 696 static const char *rpc_proc_name(const struct rpc_task *task)
 697 {
 698         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 699
 700         if (proc) {
 701                 if (proc->p_name)
 702                         return proc->p_name;
 703                 else
 704                         return "NULL";
 705         } else
 706                 return "no proc";
 707 }
 708 #endif
 709
 710 /*
 711  * 0.  Initial state
 712  *
 713  *     Other FSM states can be visited zero or more times, but
 714  *     this state is visited exactly once for each RPC.
 715  */
 716 static void
 717 call_start(struct rpc_task *task)
 718 {
 719         struct rpc_clnt *clnt = task->tk_client;
 720
 721         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
 722                         clnt->cl_protname, clnt->cl_vers,
 723                         rpc_proc_name(task),
 724                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 725
 726         /* Increment call count */
 727         task->tk_msg.rpc_proc->p_count++;
 728         clnt->cl_stats->rpccnt++;
 729         task->tk_action = call_reserve;
 730 }
 731
 732 /*
 733  * 1.   Reserve an RPC call slot
 734  */
 735 static void
 736 call_reserve(struct rpc_task *task)
 737 {
 738         dprint_status(task);
 739
 740         if (!rpcauth_uptodatecred(task)) {
 741                 task->tk_action = call_refresh;
 742                 return;
 743         }
 744
 745         task->tk_status  = 0;
 746         task->tk_action  = call_reserveresult;
 747         xprt_reserve(task);
 748 }
 749
 750 /*
 751  * 1b.  Grok the result of xprt_reserve()
 752  */
 753 static void
 754 call_reserveresult(struct rpc_task *task)
 755 {
 756         int status = task->tk_status;
 757
 758         dprint_status(task);
 759
 760         /*
 761          * After a call to xprt_reserve(), we must have either
 762          * a request slot or else an error status.
 763          */
 764         task->tk_status = 0;
 765         if (status >= 0) {
 766                 if (task->tk_rqstp) {
 767                         task->tk_action = call_allocate;
 768                         return;
 769                 }
 770
 771                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 772                                 __func__, status);
 773                 rpc_exit(task, -EIO);
 774                 return;
 775         }
 776
 777         /*
 778          * Even though there was an error, we may have acquired
 779          * a request slot somehow.  Make sure not to leak it.
 780          */
 781         if (task->tk_rqstp) {
 782                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 783                                 __func__, status);
 784                 xprt_release(task);
 785         }
 786
 787         switch (status) {
 788         case -EAGAIN:   /* woken up; retry */
 789                 task->tk_action = call_reserve;
 790                 return;
 791         case -EIO:      /* probably a shutdown */
 792                 break;
 793         default:
 794                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 795                                 __func__, status);
 796                 break;
 797         }
 798         rpc_exit(task, status);
 799 }
 800
 801 /*
 802  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 803  *      (Note: buffer memory is freed in xprt_release).
 804  */
 805 static void
 806 call_allocate(struct rpc_task *task)
 807 {
 808         unsigned int slack = task->tk_msg.rpc_cred->cr_auth->au_cslack;
 809         struct rpc_rqst *req = task->tk_rqstp;
 810         struct rpc_xprt *xprt = task->tk_xprt;
 811         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 812
 813         dprint_status(task);
 814
 815         task->tk_status = 0;
 816         task->tk_action = call_bind;
 817
 818         if (req->rq_buffer)
 819                 return;
 820
 821         if (proc->p_proc != 0) {
 822                 BUG_ON(proc->p_arglen == 0);
 823                 if (proc->p_decode != NULL)
 824                         BUG_ON(proc->p_replen == 0);
 825         }
 826
 827         /*
 828          * Calculate the size (in quads) of the RPC call
 829          * and reply headers, and convert both values
 830          * to byte sizes.
 831          */
 832         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
 833         req->rq_callsize <<= 2;
 834         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
 835         req->rq_rcvsize <<= 2;
 836
 837         req->rq_buffer = xprt->ops->buf_alloc(task,
 838                                         req->rq_callsize + req->rq_rcvsize);
 839         if (req->rq_buffer != NULL)
 840                 return;
 841
 842         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 843
 844         if (RPC_IS_ASYNC(task) || !signalled()) {
 845                 task->tk_action = call_allocate;
 846                 rpc_delay(task, HZ>>4);
 847                 return;
 848         }
 849
 850         rpc_exit(task, -ERESTARTSYS);
 851 }
 852
 853 static inline int
 854 rpc_task_need_encode(struct rpc_task *task)
 855 {
 856         return task->tk_rqstp->rq_snd_buf.len == 0;
 857 }
 858
 859 static inline void
 860 rpc_task_force_reencode(struct rpc_task *task)
 861 {
 862         task->tk_rqstp->rq_snd_buf.len = 0;
 863 }
 864
 865 static inline void
 866 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
 867 {
 868         buf->head[0].iov_base = start;
 869         buf->head[0].iov_len = len;
 870         buf->tail[0].iov_len = 0;
 871         buf->page_len = 0;
 872         buf->flags = 0;
 873         buf->len = 0;
 874         buf->buflen = len;
 875 }
 876
 877 /*
 878  * 3.   Encode arguments of an RPC call
 879  */
 880 static void
 881 rpc_xdr_encode(struct rpc_task *task)
 882 {
 883         struct rpc_rqst *req = task->tk_rqstp;
 884         kxdrproc_t      encode;
 885         __be32          *p;
 886
 887         dprint_status(task);
 888
 889         rpc_xdr_buf_init(&req->rq_snd_buf,
 890                          req->rq_buffer,
 891                          req->rq_callsize);
 892         rpc_xdr_buf_init(&req->rq_rcv_buf,
 893                          (char *)req->rq_buffer + req->rq_callsize,
 894                          req->rq_rcvsize);
 895
 896         p = rpc_encode_header(task);
 897         if (p == NULL) {
 898                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
 899                 rpc_exit(task, -EIO);
 900                 return;
 901         }
 902
 903         encode = task->tk_msg.rpc_proc->p_encode;
 904         if (encode == NULL)
 905                 return;
 906
 907         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 908                         task->tk_msg.rpc_argp);
 909 }
 910
 911 /*
 912  * 4.   Get the server port number if not yet set
 913  */
 914 static void
 915 call_bind(struct rpc_task *task)
 916 {
 917         struct rpc_xprt *xprt = task->tk_xprt;
 918
 919         dprint_status(task);
 920
 921         task->tk_action = call_connect;
 922         if (!xprt_bound(xprt)) {
 923                 task->tk_action = call_bind_status;
 924                 task->tk_timeout = xprt->bind_timeout;
 925                 xprt->ops->rpcbind(task);
 926         }
 927 }
 928
 929 /*
 930  * 4a.  Sort out bind result
 931  */
 932 static void
 933 call_bind_status(struct rpc_task *task)
 934 {
 935         int status = -EIO;
 936
 937         if (task->tk_status >= 0) {
 938                 dprint_status(task);
 939                 task->tk_status = 0;
 940                 task->tk_action = call_connect;
 941                 return;
 942         }
 943
 944         switch (task->tk_status) {
 945         case -EAGAIN:
 946                 dprintk("RPC: %5u rpcbind waiting for another request "
 947                                 "to finish\n", task->tk_pid);
 948                 /* avoid busy-waiting here -- could be a network outage. */
 949                 rpc_delay(task, 5*HZ);
 950                 goto retry_timeout;
 951         case -EACCES:
 952                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 953                                 "unavailable\n", task->tk_pid);
 954                 /* fail immediately if this is an RPC ping */
 955                 if (task->tk_msg.rpc_proc->p_proc == 0) {
 956                         status = -EOPNOTSUPP;
 957                         break;
 958                 }
 959                 rpc_delay(task, 3*HZ);
 960                 goto retry_timeout;
 961         case -ETIMEDOUT:
 962                 dprintk("RPC: %5u rpcbind request timed out\n",
 963                                 task->tk_pid);
 964                 goto retry_timeout;
 965         case -EPFNOSUPPORT:
 966                 /* server doesn't support any rpcbind version we know of */
 967                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 968                                 task->tk_pid);
 969                 break;
 970         case -EPROTONOSUPPORT:
 971                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
 972                                 task->tk_pid);
 973                 task->tk_status = 0;
 974                 task->tk_action = call_bind;
 975                 return;
 976         default:
 977                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 978                                 task->tk_pid, -task->tk_status);
 979         }
 980
 981         rpc_exit(task, status);
 982         return;
 983
 984 retry_timeout:
 985         task->tk_action = call_timeout;
 986 }
 987
 988 /*
 989  * 4b.  Connect to the RPC server
 990  */
 991 static void
 992 call_connect(struct rpc_task *task)
 993 {
 994         struct rpc_xprt *xprt = task->tk_xprt;
 995
 996         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
 997                         task->tk_pid, xprt,
 998                         (xprt_connected(xprt) ? "is" : "is not"));
 999
1000         task->tk_action = call_transmit;
1001         if (!xprt_connected(xprt)) {
1002                 task->tk_action = call_connect_status;
1003                 if (task->tk_status < 0)
1004                         return;
1005                 xprt_connect(task);
1006         }
1007 }
1008
1009 /*
1010  * 4c.  Sort out connect result
1011  */
1012 static void
1013 call_connect_status(struct rpc_task *task)
1014 {
1015         struct rpc_clnt *clnt = task->tk_client;
1016         int status = task->tk_status;
1017
1018         dprint_status(task);
1019
1020         task->tk_status = 0;
1021         if (status >= 0) {
1022                 clnt->cl_stats->netreconn++;
1023                 task->tk_action = call_transmit;
1024                 return;
1025         }
1026
1027         /* Something failed: remote service port may have changed */
1028         rpc_force_rebind(clnt);
1029
1030         switch (status) {
1031         case -ENOTCONN:
1032         case -EAGAIN:
1033                 task->tk_action = call_bind;
1034                 if (!RPC_IS_SOFT(task))
1035                         return;
1036                 /* if soft mounted, test if we've timed out */
1037         case -ETIMEDOUT:
1038                 task->tk_action = call_timeout;
1039                 return;
1040         }
1041         rpc_exit(task, -EIO);
1042 }
1043
1044 /*
1045  * 5.   Transmit the RPC request, and wait for reply
1046  */
1047 static void
1048 call_transmit(struct rpc_task *task)
1049 {
1050         dprint_status(task);
1051
1052         task->tk_action = call_status;
1053         if (task->tk_status < 0)
1054                 return;
1055         task->tk_status = xprt_prepare_transmit(task);
1056         if (task->tk_status != 0)
1057                 return;
1058         task->tk_action = call_transmit_status;
1059         /* Encode here so that rpcsec_gss can use correct sequence number. */
1060         if (rpc_task_need_encode(task)) {
1061                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1062                 rpc_xdr_encode(task);
1063                 /* Did the encode result in an error condition? */
1064                 if (task->tk_status != 0) {
1065                         /* Was the error nonfatal? */
1066                         if (task->tk_status == -EAGAIN)
1067                                 rpc_delay(task, HZ >> 4);
1068                         else
1069                                 rpc_exit(task, task->tk_status);
1070                         return;
1071                 }
1072         }
1073         xprt_transmit(task);
1074         if (task->tk_status < 0)
1075                 return;
1076         /*
1077          * On success, ensure that we call xprt_end_transmit() before sleeping
1078          * in order to allow access to the socket to other RPC requests.
1079          */
1080         call_transmit_status(task);
1081         if (task->tk_msg.rpc_proc->p_decode != NULL)
1082                 return;
1083         task->tk_action = rpc_exit_task;
1084         rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
1085 }
1086
1087 /*
1088  * 5a.  Handle cleanup after a transmission
1089  */
1090 static void
1091 call_transmit_status(struct rpc_task *task)
1092 {
1093         task->tk_action = call_status;
1094         /*
1095          * Special case: if we've been waiting on the socket's write_space()
1096          * callback, then don't call xprt_end_transmit().
1097          */
1098         if (task->tk_status == -EAGAIN)
1099                 return;
1100         xprt_end_transmit(task);
1101         rpc_task_force_reencode(task);
1102 }
1103
1104 /*
1105  * 6.   Sort out the RPC call status
1106  */
1107 static void
1108 call_status(struct rpc_task *task)
1109 {
1110         struct rpc_clnt *clnt = task->tk_client;
1111         struct rpc_rqst *req = task->tk_rqstp;
1112         int             status;
1113
1114         if (req->rq_received > 0 && !req->rq_bytes_sent)
1115                 task->tk_status = req->rq_received;
1116
1117         dprint_status(task);
1118
1119         status = task->tk_status;
1120         if (status >= 0) {
1121                 task->tk_action = call_decode;
1122                 return;
1123         }
1124
1125         task->tk_status = 0;
1126         switch(status) {
1127         case -EHOSTDOWN:
1128         case -EHOSTUNREACH:
1129         case -ENETUNREACH:
1130                 /*
1131                  * Delay any retries for 3 seconds, then handle as if it
1132                  * were a timeout.
1133                  */
1134                 rpc_delay(task, 3*HZ);
1135         case -ETIMEDOUT:
1136                 task->tk_action = call_timeout;
1137                 if (task->tk_client->cl_discrtry)
1138                         xprt_conditional_disconnect(task->tk_xprt,
1139                                         req->rq_connect_cookie);
1140                 break;
1141         case -ECONNREFUSED:
1142         case -ENOTCONN:
1143                 rpc_force_rebind(clnt);
1144                 task->tk_action = call_bind;
1145                 break;
1146         case -EAGAIN:
1147                 task->tk_action = call_transmit;
1148                 break;
1149         case -EIO:
1150                 /* shutdown or soft timeout */
1151                 rpc_exit(task, status);
1152                 break;
1153         default:
1154                 if (clnt->cl_chatty)
1155                         printk("%s: RPC call returned error %d\n",
1156                                clnt->cl_protname, -status);
1157                 rpc_exit(task, status);
1158         }
1159 }
1160
1161 /*
1162  * 6a.  Handle RPC timeout
1163  *      We do not release the request slot, so we keep using the
1164  *      same XID for all retransmits.
1165  */
1166 static void
1167 call_timeout(struct rpc_task *task)
1168 {
1169         struct rpc_clnt *clnt = task->tk_client;
1170
1171         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1172                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1173                 goto retry;
1174         }
1175
1176         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1177         task->tk_timeouts++;
1178
1179         if (RPC_IS_SOFT(task)) {
1180                 if (clnt->cl_chatty)
1181                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1182                                 clnt->cl_protname, clnt->cl_server);
1183                 rpc_exit(task, -EIO);
1184                 return;
1185         }
1186
1187         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1188                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1189                 if (clnt->cl_chatty)
1190                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1191                         clnt->cl_protname, clnt->cl_server);
1192         }
1193         rpc_force_rebind(clnt);
1194         /*
1195          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1196          * event? RFC2203 requires the server to drop all such requests.
1197          */
1198         rpcauth_invalcred(task);
1199
1200 retry:
1201         clnt->cl_stats->rpcretrans++;
1202         task->tk_action = call_bind;
1203         task->tk_status = 0;
1204 }
1205
1206 /*
1207  * 7.   Decode the RPC reply
1208  */
1209 static void
1210 call_decode(struct rpc_task *task)
1211 {
1212         struct rpc_clnt *clnt = task->tk_client;
1213         struct rpc_rqst *req = task->tk_rqstp;
1214         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1215         __be32          *p;
1216
1217         dprintk("RPC: %5u call_decode (status %d)\n",
1218                         task->tk_pid, task->tk_status);
1219
1220         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1221                 if (clnt->cl_chatty)
1222                         printk(KERN_NOTICE "%s: server %s OK\n",
1223                                 clnt->cl_protname, clnt->cl_server);
1224                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1225         }
1226
1227         /*
1228          * Ensure that we see all writes made by xprt_complete_rqst()
1229          * before it changed req->rq_received.
1230          */
1231         smp_rmb();
1232         req->rq_rcv_buf.len = req->rq_private_buf.len;
1233
1234         /* Check that the softirq receive buffer is valid */
1235         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1236                                 sizeof(req->rq_rcv_buf)) != 0);
1237
1238         if (req->rq_rcv_buf.len < 12) {
1239                 if (!RPC_IS_SOFT(task)) {
1240                         task->tk_action = call_bind;
1241                         clnt->cl_stats->rpcretrans++;
1242                         goto out_retry;
1243                 }
1244                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1245                                 clnt->cl_protname, task->tk_status);
1246                 task->tk_action = call_timeout;
1247                 goto out_retry;
1248         }
1249
1250         p = rpc_verify_header(task);
1251         if (IS_ERR(p)) {
1252                 if (p == ERR_PTR(-EAGAIN))
1253                         goto out_retry;
1254                 return;
1255         }
1256
1257         task->tk_action = rpc_exit_task;
1258
1259         if (decode) {
1260                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1261                                                       task->tk_msg.rpc_resp);
1262         }
1263         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1264                         task->tk_status);
1265         return;
1266 out_retry:
1267         task->tk_status = 0;
1268         /* Note: rpc_verify_header() may have freed the RPC slot */
1269         if (task->tk_rqstp == req) {
1270                 req->rq_received = req->rq_rcv_buf.len = 0;
1271                 if (task->tk_client->cl_discrtry)
1272                         xprt_conditional_disconnect(task->tk_xprt,
1273                                         req->rq_connect_cookie);
1274         }
1275 }
1276
1277 /*
1278  * 8.   Refresh the credentials if rejected by the server
1279  */
1280 static void
1281 call_refresh(struct rpc_task *task)
1282 {
1283         dprint_status(task);
1284
1285         task->tk_action = call_refreshresult;
1286         task->tk_status = 0;
1287         task->tk_client->cl_stats->rpcauthrefresh++;
1288         rpcauth_refreshcred(task);
1289 }
1290
1291 /*
1292  * 8a.  Process the results of a credential refresh
1293  */
1294 static void
1295 call_refreshresult(struct rpc_task *task)
1296 {
1297         int status = task->tk_status;
1298
1299         dprint_status(task);
1300
1301         task->tk_status = 0;
1302         task->tk_action = call_reserve;
1303         if (status >= 0 && rpcauth_uptodatecred(task))
1304                 return;
1305         if (status == -EACCES) {
1306                 rpc_exit(task, -EACCES);
1307                 return;
1308         }
1309         task->tk_action = call_refresh;
1310         if (status != -ETIMEDOUT)
1311                 rpc_delay(task, 3*HZ);
1312         return;
1313 }
1314
1315 static __be32 *
1316 rpc_encode_header(struct rpc_task *task)
1317 {
1318         struct rpc_clnt *clnt = task->tk_client;
1319         struct rpc_rqst *req = task->tk_rqstp;
1320         __be32          *p = req->rq_svec[0].iov_base;
1321
1322         /* FIXME: check buffer size? */
1323
1324         p = xprt_skip_transport_header(task->tk_xprt, p);
1325         *p++ = req->rq_xid;             /* XID */
1326         *p++ = htonl(RPC_CALL);         /* CALL */
1327         *p++ = htonl(RPC_VERSION);      /* RPC version */
1328         *p++ = htonl(clnt->cl_prog);    /* program number */
1329         *p++ = htonl(clnt->cl_vers);    /* program version */
1330         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1331         p = rpcauth_marshcred(task, p);
1332         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1333         return p;
1334 }
1335
1336 static __be32 *
1337 rpc_verify_header(struct rpc_task *task)
1338 {
1339         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1340         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1341         __be32  *p = iov->iov_base;
1342         u32 n;
1343         int error = -EACCES;
1344
1345         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1346                 /* RFC-1014 says that the representation of XDR data must be a
1347                  * multiple of four bytes
1348                  * - if it isn't pointer subtraction in the NFS client may give
1349                  *   undefined results
1350                  */
1351                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1352                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
1353                        task->tk_rqstp->rq_rcv_buf.len);
1354                 goto out_eio;
1355         }
1356         if ((len -= 3) < 0)
1357                 goto out_overflow;
1358         p += 1; /* skip XID */
1359
1360         if ((n = ntohl(*p++)) != RPC_REPLY) {
1361                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1362                                 task->tk_pid, __func__, n);
1363                 goto out_garbage;
1364         }
1365         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1366                 if (--len < 0)
1367                         goto out_overflow;
1368                 switch ((n = ntohl(*p++))) {
1369                         case RPC_AUTH_ERROR:
1370                                 break;
1371                         case RPC_MISMATCH:
1372                                 dprintk("RPC: %5u %s: RPC call version "
1373                                                 "mismatch!\n",
1374                                                 task->tk_pid, __func__);
1375                                 error = -EPROTONOSUPPORT;
1376                                 goto out_err;
1377                         default:
1378                                 dprintk("RPC: %5u %s: RPC call rejected, "
1379                                                 "unknown error: %x\n",
1380                                                 task->tk_pid, __func__, n);
1381                                 goto out_eio;
1382                 }
1383                 if (--len < 0)
1384                         goto out_overflow;
1385                 switch ((n = ntohl(*p++))) {
1386                 case RPC_AUTH_REJECTEDCRED:
1387                 case RPC_AUTH_REJECTEDVERF:
1388                 case RPCSEC_GSS_CREDPROBLEM:
1389                 case RPCSEC_GSS_CTXPROBLEM:
1390                         if (!task->tk_cred_retry)
1391                                 break;
1392                         task->tk_cred_retry--;
1393                         dprintk("RPC: %5u %s: retry stale creds\n",
1394                                         task->tk_pid, __func__);
1395                         rpcauth_invalcred(task);
1396                         /* Ensure we obtain a new XID! */
1397                         xprt_release(task);
1398                         task->tk_action = call_refresh;
1399                         goto out_retry;
1400                 case RPC_AUTH_BADCRED:
1401                 case RPC_AUTH_BADVERF:
1402                         /* possibly garbled cred/verf? */
1403                         if (!task->tk_garb_retry)
1404                                 break;
1405                         task->tk_garb_retry--;
1406                         dprintk("RPC: %5u %s: retry garbled creds\n",
1407                                         task->tk_pid, __func__);
1408                         task->tk_action = call_bind;
1409                         goto out_retry;
1410                 case RPC_AUTH_TOOWEAK:
1411                         printk(KERN_NOTICE "RPC: server %s requires stronger "
1412                                "authentication.\n", task->tk_client->cl_server);
1413                         break;
1414                 default:
1415                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1416                                         task->tk_pid, __func__, n);
1417                         error = -EIO;
1418                 }
1419                 dprintk("RPC: %5u %s: call rejected %d\n",
1420                                 task->tk_pid, __func__, n);
1421                 goto out_err;
1422         }
1423         if (!(p = rpcauth_checkverf(task, p))) {
1424                 dprintk("RPC: %5u %s: auth check failed\n",
1425                                 task->tk_pid, __func__);
1426                 goto out_garbage;               /* bad verifier, retry */
1427         }
1428         len = p - (__be32 *)iov->iov_base - 1;
1429         if (len < 0)
1430                 goto out_overflow;
1431         switch ((n = ntohl(*p++))) {
1432         case RPC_SUCCESS:
1433                 return p;
1434         case RPC_PROG_UNAVAIL:
1435                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1436                                 task->tk_pid, __func__,
1437                                 (unsigned int)task->tk_client->cl_prog,
1438                                 task->tk_client->cl_server);
1439                 error = -EPFNOSUPPORT;
1440                 goto out_err;
1441         case RPC_PROG_MISMATCH:
1442                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1443                                 "server %s\n", task->tk_pid, __func__,
1444                                 (unsigned int)task->tk_client->cl_prog,
1445                                 (unsigned int)task->tk_client->cl_vers,
1446                                 task->tk_client->cl_server);
1447                 error = -EPROTONOSUPPORT;
1448                 goto out_err;
1449         case RPC_PROC_UNAVAIL:
1450                 dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
1451                                 "version %u on server %s\n",
1452                                 task->tk_pid, __func__,
1453                                 rpc_proc_name(task),
1454                                 task->tk_client->cl_prog,
1455                                 task->tk_client->cl_vers,
1456                                 task->tk_client->cl_server);
1457                 error = -EOPNOTSUPP;
1458                 goto out_err;
1459         case RPC_GARBAGE_ARGS:
1460                 dprintk("RPC: %5u %s: server saw garbage\n",
1461                                 task->tk_pid, __func__);
1462                 break;                  /* retry */
1463         default:
1464                 dprintk("RPC: %5u %s: server accept status: %x\n",
1465                                 task->tk_pid, __func__, n);
1466                 /* Also retry */
1467         }
1468
1469 out_garbage:
1470         task->tk_client->cl_stats->rpcgarbage++;
1471         if (task->tk_garb_retry) {
1472                 task->tk_garb_retry--;
1473                 dprintk("RPC: %5u %s: retrying\n",
1474                                 task->tk_pid, __func__);
1475                 task->tk_action = call_bind;
1476 out_retry:
1477                 return ERR_PTR(-EAGAIN);
1478         }
1479 out_eio:
1480         error = -EIO;
1481 out_err:
1482         rpc_exit(task, error);
1483         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1484                         __func__, error);
1485         return ERR_PTR(error);
1486 out_overflow:
1487         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1488                         __func__);
1489         goto out_garbage;
1490 }
1491
1492 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1493 {
1494         return 0;
1495 }
1496
1497 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1498 {
1499         return 0;
1500 }
1501
1502 static struct rpc_procinfo rpcproc_null = {
1503         .p_encode = rpcproc_encode_null,
1504         .p_decode = rpcproc_decode_null,
1505 };
1506
1507 static int rpc_ping(struct rpc_clnt *clnt, int flags)
1508 {
1509         struct rpc_message msg = {
1510                 .rpc_proc = &rpcproc_null,
1511         };
1512         int err;
1513         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1514         err = rpc_call_sync(clnt, &msg, flags);
1515         put_rpccred(msg.rpc_cred);
1516         return err;
1517 }
1518
1519 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1520 {
1521         struct rpc_message msg = {
1522                 .rpc_proc = &rpcproc_null,
1523                 .rpc_cred = cred,
1524         };
1525         struct rpc_task_setup task_setup_data = {
1526                 .rpc_client = clnt,
1527                 .rpc_message = &msg,
1528                 .callback_ops = &rpc_default_ops,
1529                 .flags = flags,
1530         };
1531         return rpc_run_task(&task_setup_data);
1532 }
1533 EXPORT_SYMBOL_GPL(rpc_call_null);
1534
1535 #ifdef RPC_DEBUG
1536 static void rpc_show_header(void)
1537 {
1538         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
1539                 "-timeout ---ops--\n");
1540 }
1541
1542 static void rpc_show_task(const struct rpc_clnt *clnt,
1543                           const struct rpc_task *task)
1544 {
1545         const char *rpc_waitq = "none";
1546         char *p, action[KSYM_SYMBOL_LEN];
1547
1548         if (RPC_IS_QUEUED(task))
1549                 rpc_waitq = rpc_qname(task->tk_waitqueue);
1550
1551         /* map tk_action pointer to a function name; then trim off
1552          * the "+0x0 [sunrpc]" */
1553         sprint_symbol(action, (unsigned long)task->tk_action);
1554         p = strchr(action, '+');
1555         if (p)
1556                 *p = '\0';
1557
1558         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%s q:%s\n",
1559                 task->tk_pid, task->tk_flags, task->tk_status,
1560                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
1561                 clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
1562                 action, rpc_waitq);
1563 }
1564
1565 void rpc_show_tasks(void)
1566 {
1567         struct rpc_clnt *clnt;
1568         struct rpc_task *task;
1569         int header = 0;
1570
1571         spin_lock(&rpc_client_lock);
1572         list_for_each_entry(clnt, &all_clients, cl_clients) {
1573                 spin_lock(&clnt->cl_lock);
1574                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
1575                         if (!header) {
1576                                 rpc_show_header();
1577                                 header++;
1578                         }
1579                         rpc_show_task(clnt, task);
1580                 }
1581                 spin_unlock(&clnt->cl_lock);
1582         }
1583         spin_unlock(&rpc_client_lock);
1584 }
1585 #endif