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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     = args->prognumber ? : 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         clnt->cl_principal = NULL;
 201         if (args->client_name) {
 202                 clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
 203                 if (!clnt->cl_principal)
 204                         goto out_no_principal;
 205         }
 206
 207         kref_init(&clnt->cl_kref);
 208
 209         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 210         if (err < 0)
 211                 goto out_no_path;
 212
 213         auth = rpcauth_create(args->authflavor, clnt);
 214         if (IS_ERR(auth)) {
 215                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 216                                 args->authflavor);
 217                 err = PTR_ERR(auth);
 218                 goto out_no_auth;
 219         }
 220
 221         /* save the nodename */
 222         clnt->cl_nodelen = strlen(init_utsname()->nodename);
 223         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 224                 clnt->cl_nodelen = UNX_MAXNODENAME;
 225         memcpy(clnt->cl_nodename, init_utsname()->nodename, clnt->cl_nodelen);
 226         rpc_register_client(clnt);
 227         return clnt;
 228
 229 out_no_auth:
 230         if (!IS_ERR(clnt->cl_dentry)) {
 231                 rpc_rmdir(clnt->cl_dentry);
 232                 rpc_put_mount();
 233         }
 234 out_no_path:
 235         kfree(clnt->cl_principal);
 236 out_no_principal:
 237         rpc_free_iostats(clnt->cl_metrics);
 238 out_no_stats:
 239         if (clnt->cl_server != clnt->cl_inline_name)
 240                 kfree(clnt->cl_server);
 241         kfree(clnt);
 242 out_err:
 243         xprt_put(xprt);
 244 out_no_xprt:
 245         rpciod_down();
 246 out_no_rpciod:
 247         return ERR_PTR(err);
 248 }
 249
 250 /*
 251  * rpc_create - create an RPC client and transport with one call
 252  * @args: rpc_clnt create argument structure
 253  *
 254  * Creates and initializes an RPC transport and an RPC client.
 255  *
 256  * It can ping the server in order to determine if it is up, and to see if
 257  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 258  * this behavior so asynchronous tasks can also use rpc_create.
 259  */
 260 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 261 {
 262         struct rpc_xprt *xprt;
 263         struct rpc_clnt *clnt;
 264         struct xprt_create xprtargs = {
 265                 .ident = args->protocol,
 266                 .srcaddr = args->saddress,
 267                 .dstaddr = args->address,
 268                 .addrlen = args->addrsize,
 269         };
 270         char servername[48];
 271
 272         /*
 273          * If the caller chooses not to specify a hostname, whip
 274          * up a string representation of the passed-in address.
 275          */
 276         if (args->servername == NULL) {
 277                 servername[0] = '\0';
 278                 switch (args->address->sa_family) {
 279                 case AF_INET: {
 280                         struct sockaddr_in *sin =
 281                                         (struct sockaddr_in *)args->address;
 282                         snprintf(servername, sizeof(servername), "%pI4",
 283                                  &sin->sin_addr.s_addr);
 284                         break;
 285                 }
 286                 case AF_INET6: {
 287                         struct sockaddr_in6 *sin =
 288                                         (struct sockaddr_in6 *)args->address;
 289                         snprintf(servername, sizeof(servername), "%pI6",
 290                                  &sin->sin6_addr);
 291                         break;
 292                 }
 293                 default:
 294                         /* caller wants default server name, but
 295                          * address family isn't recognized. */
 296                         return ERR_PTR(-EINVAL);
 297                 }
 298                 args->servername = servername;
 299         }
 300
 301         xprt = xprt_create_transport(&xprtargs);
 302         if (IS_ERR(xprt))
 303                 return (struct rpc_clnt *)xprt;
 304
 305         /*
 306          * By default, kernel RPC client connects from a reserved port.
 307          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 308          * but it is always enabled for rpciod, which handles the connect
 309          * operation.
 310          */
 311         xprt->resvport = 1;
 312         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 313                 xprt->resvport = 0;
 314
 315         clnt = rpc_new_client(args, xprt);
 316         if (IS_ERR(clnt))
 317                 return clnt;
 318
 319         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 320                 int err = rpc_ping(clnt, RPC_TASK_SOFT);
 321                 if (err != 0) {
 322                         rpc_shutdown_client(clnt);
 323                         return ERR_PTR(err);
 324                 }
 325         }
 326
 327         clnt->cl_softrtry = 1;
 328         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 329                 clnt->cl_softrtry = 0;
 330
 331         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 332                 clnt->cl_autobind = 1;
 333         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 334                 clnt->cl_discrtry = 1;
 335         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 336                 clnt->cl_chatty = 1;
 337
 338         return clnt;
 339 }
 340 EXPORT_SYMBOL_GPL(rpc_create);
 341
 342 /*
 343  * This function clones the RPC client structure. It allows us to share the
 344  * same transport while varying parameters such as the authentication
 345  * flavour.
 346  */
 347 struct rpc_clnt *
 348 rpc_clone_client(struct rpc_clnt *clnt)
 349 {
 350         struct rpc_clnt *new;
 351         int err = -ENOMEM;
 352
 353         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 354         if (!new)
 355                 goto out_no_clnt;
 356         new->cl_parent = clnt;
 357         /* Turn off autobind on clones */
 358         new->cl_autobind = 0;
 359         INIT_LIST_HEAD(&new->cl_tasks);
 360         spin_lock_init(&new->cl_lock);
 361         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);
 362         new->cl_metrics = rpc_alloc_iostats(clnt);
 363         if (new->cl_metrics == NULL)
 364                 goto out_no_stats;
 365         if (clnt->cl_principal) {
 366                 new->cl_principal = kstrdup(clnt->cl_principal, GFP_KERNEL);
 367                 if (new->cl_principal == NULL)
 368                         goto out_no_principal;
 369         }
 370         kref_init(&new->cl_kref);
 371         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 372         if (err != 0)
 373                 goto out_no_path;
 374         if (new->cl_auth)
 375                 atomic_inc(&new->cl_auth->au_count);
 376         xprt_get(clnt->cl_xprt);
 377         kref_get(&clnt->cl_kref);
 378         rpc_register_client(new);
 379         rpciod_up();
 380         return new;
 381 out_no_path:
 382         kfree(new->cl_principal);
 383 out_no_principal:
 384         rpc_free_iostats(new->cl_metrics);
 385 out_no_stats:
 386         kfree(new);
 387 out_no_clnt:
 388         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 389         return ERR_PTR(err);
 390 }
 391 EXPORT_SYMBOL_GPL(rpc_clone_client);
 392
 393 /*
 394  * Properly shut down an RPC client, terminating all outstanding
 395  * requests.
 396  */
 397 void rpc_shutdown_client(struct rpc_clnt *clnt)
 398 {
 399         dprintk("RPC:       shutting down %s client for %s\n",
 400                         clnt->cl_protname, clnt->cl_server);
 401
 402         while (!list_empty(&clnt->cl_tasks)) {
 403                 rpc_killall_tasks(clnt);
 404                 wait_event_timeout(destroy_wait,
 405                         list_empty(&clnt->cl_tasks), 1*HZ);
 406         }
 407
 408         rpc_release_client(clnt);
 409 }
 410 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 411
 412 /*
 413  * Free an RPC client
 414  */
 415 static void
 416 rpc_free_client(struct kref *kref)
 417 {
 418         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 419
 420         dprintk("RPC:       destroying %s client for %s\n",
 421                         clnt->cl_protname, clnt->cl_server);
 422         if (!IS_ERR(clnt->cl_dentry)) {
 423                 rpc_rmdir(clnt->cl_dentry);
 424                 rpc_put_mount();
 425         }
 426         if (clnt->cl_parent != clnt) {
 427                 rpc_release_client(clnt->cl_parent);
 428                 goto out_free;
 429         }
 430         if (clnt->cl_server != clnt->cl_inline_name)
 431                 kfree(clnt->cl_server);
 432 out_free:
 433         rpc_unregister_client(clnt);
 434         rpc_free_iostats(clnt->cl_metrics);
 435         kfree(clnt->cl_principal);
 436         clnt->cl_metrics = NULL;
 437         xprt_put(clnt->cl_xprt);
 438         rpciod_down();
 439         kfree(clnt);
 440 }
 441
 442 /*
 443  * Free an RPC client
 444  */
 445 static void
 446 rpc_free_auth(struct kref *kref)
 447 {
 448         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 449
 450         if (clnt->cl_auth == NULL) {
 451                 rpc_free_client(kref);
 452                 return;
 453         }
 454
 455         /*
 456          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 457          *       release remaining GSS contexts. This mechanism ensures
 458          *       that it can do so safely.
 459          */
 460         kref_init(kref);
 461         rpcauth_release(clnt->cl_auth);
 462         clnt->cl_auth = NULL;
 463         kref_put(kref, rpc_free_client);
 464 }
 465
 466 /*
 467  * Release reference to the RPC client
 468  */
 469 void
 470 rpc_release_client(struct rpc_clnt *clnt)
 471 {
 472         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 473
 474         if (list_empty(&clnt->cl_tasks))
 475                 wake_up(&destroy_wait);
 476         kref_put(&clnt->cl_kref, rpc_free_auth);
 477 }
 478
 479 /**
 480  * rpc_bind_new_program - bind a new RPC program to an existing client
 481  * @old: old rpc_client
 482  * @program: rpc program to set
 483  * @vers: rpc program version
 484  *
 485  * Clones the rpc client and sets up a new RPC program. This is mainly
 486  * of use for enabling different RPC programs to share the same transport.
 487  * The Sun NFSv2/v3 ACL protocol can do this.
 488  */
 489 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 490                                       struct rpc_program *program,
 491                                       u32 vers)
 492 {
 493         struct rpc_clnt *clnt;
 494         struct rpc_version *version;
 495         int err;
 496
 497         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 498         version = program->version[vers];
 499         clnt = rpc_clone_client(old);
 500         if (IS_ERR(clnt))
 501                 goto out;
 502         clnt->cl_procinfo = version->procs;
 503         clnt->cl_maxproc  = version->nrprocs;
 504         clnt->cl_protname = program->name;
 505         clnt->cl_prog     = program->number;
 506         clnt->cl_vers     = version->number;
 507         clnt->cl_stats    = program->stats;
 508         err = rpc_ping(clnt, RPC_TASK_SOFT);
 509         if (err != 0) {
 510                 rpc_shutdown_client(clnt);
 511                 clnt = ERR_PTR(err);
 512         }
 513 out:
 514         return clnt;
 515 }
 516 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 517
 518 /*
 519  * Default callback for async RPC calls
 520  */
 521 static void
 522 rpc_default_callback(struct rpc_task *task, void *data)
 523 {
 524 }
 525
 526 static const struct rpc_call_ops rpc_default_ops = {
 527         .rpc_call_done = rpc_default_callback,
 528 };
 529
 530 /**
 531  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 532  * @task_setup_data: pointer to task initialisation data
 533  */
 534 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 535 {
 536         struct rpc_task *task, *ret;
 537
 538         task = rpc_new_task(task_setup_data);
 539         if (task == NULL) {
 540                 rpc_release_calldata(task_setup_data->callback_ops,
 541                                 task_setup_data->callback_data);
 542                 ret = ERR_PTR(-ENOMEM);
 543                 goto out;
 544         }
 545
 546         if (task->tk_status != 0) {
 547                 ret = ERR_PTR(task->tk_status);
 548                 rpc_put_task(task);
 549                 goto out;
 550         }
 551         atomic_inc(&task->tk_count);
 552         rpc_execute(task);
 553         ret = task;
 554 out:
 555         return ret;
 556 }
 557 EXPORT_SYMBOL_GPL(rpc_run_task);
 558
 559 /**
 560  * rpc_call_sync - Perform a synchronous RPC call
 561  * @clnt: pointer to RPC client
 562  * @msg: RPC call parameters
 563  * @flags: RPC call flags
 564  */
 565 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 566 {
 567         struct rpc_task *task;
 568         struct rpc_task_setup task_setup_data = {
 569                 .rpc_client = clnt,
 570                 .rpc_message = msg,
 571                 .callback_ops = &rpc_default_ops,
 572                 .flags = flags,
 573         };
 574         int status;
 575
 576         BUG_ON(flags & RPC_TASK_ASYNC);
 577
 578         task = rpc_run_task(&task_setup_data);
 579         if (IS_ERR(task))
 580                 return PTR_ERR(task);
 581         status = task->tk_status;
 582         rpc_put_task(task);
 583         return status;
 584 }
 585 EXPORT_SYMBOL_GPL(rpc_call_sync);
 586
 587 /**
 588  * rpc_call_async - Perform an asynchronous RPC call
 589  * @clnt: pointer to RPC client
 590  * @msg: RPC call parameters
 591  * @flags: RPC call flags
 592  * @tk_ops: RPC call ops
 593  * @data: user call data
 594  */
 595 int
 596 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
 597                const struct rpc_call_ops *tk_ops, void *data)
 598 {
 599         struct rpc_task *task;
 600         struct rpc_task_setup task_setup_data = {
 601                 .rpc_client = clnt,
 602                 .rpc_message = msg,
 603                 .callback_ops = tk_ops,
 604                 .callback_data = data,
 605                 .flags = flags|RPC_TASK_ASYNC,
 606         };
 607
 608         task = rpc_run_task(&task_setup_data);
 609         if (IS_ERR(task))
 610                 return PTR_ERR(task);
 611         rpc_put_task(task);
 612         return 0;
 613 }
 614 EXPORT_SYMBOL_GPL(rpc_call_async);
 615
 616 void
 617 rpc_call_start(struct rpc_task *task)
 618 {
 619         task->tk_action = call_start;
 620 }
 621 EXPORT_SYMBOL_GPL(rpc_call_start);
 622
 623 /**
 624  * rpc_peeraddr - extract remote peer address from clnt's xprt
 625  * @clnt: RPC client structure
 626  * @buf: target buffer
 627  * @bufsize: length of target buffer
 628  *
 629  * Returns the number of bytes that are actually in the stored address.
 630  */
 631 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 632 {
 633         size_t bytes;
 634         struct rpc_xprt *xprt = clnt->cl_xprt;
 635
 636         bytes = sizeof(xprt->addr);
 637         if (bytes > bufsize)
 638                 bytes = bufsize;
 639         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 640         return xprt->addrlen;
 641 }
 642 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 643
 644 /**
 645  * rpc_peeraddr2str - return remote peer address in printable format
 646  * @clnt: RPC client structure
 647  * @format: address format
 648  *
 649  */
 650 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
 651                              enum rpc_display_format_t format)
 652 {
 653         struct rpc_xprt *xprt = clnt->cl_xprt;
 654
 655         if (xprt->address_strings[format] != NULL)
 656                 return xprt->address_strings[format];
 657         else
 658                 return "unprintable";
 659 }
 660 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 661
 662 void
 663 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 664 {
 665         struct rpc_xprt *xprt = clnt->cl_xprt;
 666         if (xprt->ops->set_buffer_size)
 667                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 668 }
 669 EXPORT_SYMBOL_GPL(rpc_setbufsize);
 670
 671 /*
 672  * Return size of largest payload RPC client can support, in bytes
 673  *
 674  * For stream transports, this is one RPC record fragment (see RFC
 675  * 1831), as we don't support multi-record requests yet.  For datagram
 676  * transports, this is the size of an IP packet minus the IP, UDP, and
 677  * RPC header sizes.
 678  */
 679 size_t rpc_max_payload(struct rpc_clnt *clnt)
 680 {
 681         return clnt->cl_xprt->max_payload;
 682 }
 683 EXPORT_SYMBOL_GPL(rpc_max_payload);
 684
 685 /**
 686  * rpc_force_rebind - force transport to check that remote port is unchanged
 687  * @clnt: client to rebind
 688  *
 689  */
 690 void rpc_force_rebind(struct rpc_clnt *clnt)
 691 {
 692         if (clnt->cl_autobind)
 693                 xprt_clear_bound(clnt->cl_xprt);
 694 }
 695 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 696
 697 /*
 698  * Restart an (async) RPC call. Usually called from within the
 699  * exit handler.
 700  */
 701 void
 702 rpc_restart_call(struct rpc_task *task)
 703 {
 704         if (RPC_ASSASSINATED(task))
 705                 return;
 706
 707         task->tk_action = call_start;
 708 }
 709 EXPORT_SYMBOL_GPL(rpc_restart_call);
 710
 711 #ifdef RPC_DEBUG
 712 static const char *rpc_proc_name(const struct rpc_task *task)
 713 {
 714         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 715
 716         if (proc) {
 717                 if (proc->p_name)
 718                         return proc->p_name;
 719                 else
 720                         return "NULL";
 721         } else
 722                 return "no proc";
 723 }
 724 #endif
 725
 726 /*
 727  * 0.  Initial state
 728  *
 729  *     Other FSM states can be visited zero or more times, but
 730  *     this state is visited exactly once for each RPC.
 731  */
 732 static void
 733 call_start(struct rpc_task *task)
 734 {
 735         struct rpc_clnt *clnt = task->tk_client;
 736
 737         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
 738                         clnt->cl_protname, clnt->cl_vers,
 739                         rpc_proc_name(task),
 740                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 741
 742         /* Increment call count */
 743         task->tk_msg.rpc_proc->p_count++;
 744         clnt->cl_stats->rpccnt++;
 745         task->tk_action = call_reserve;
 746 }
 747
 748 /*
 749  * 1.   Reserve an RPC call slot
 750  */
 751 static void
 752 call_reserve(struct rpc_task *task)
 753 {
 754         dprint_status(task);
 755
 756         if (!rpcauth_uptodatecred(task)) {
 757                 task->tk_action = call_refresh;
 758                 return;
 759         }
 760
 761         task->tk_status  = 0;
 762         task->tk_action  = call_reserveresult;
 763         xprt_reserve(task);
 764 }
 765
 766 /*
 767  * 1b.  Grok the result of xprt_reserve()
 768  */
 769 static void
 770 call_reserveresult(struct rpc_task *task)
 771 {
 772         int status = task->tk_status;
 773
 774         dprint_status(task);
 775
 776         /*
 777          * After a call to xprt_reserve(), we must have either
 778          * a request slot or else an error status.
 779          */
 780         task->tk_status = 0;
 781         if (status >= 0) {
 782                 if (task->tk_rqstp) {
 783                         task->tk_action = call_allocate;
 784                         return;
 785                 }
 786
 787                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 788                                 __func__, status);
 789                 rpc_exit(task, -EIO);
 790                 return;
 791         }
 792
 793         /*
 794          * Even though there was an error, we may have acquired
 795          * a request slot somehow.  Make sure not to leak it.
 796          */
 797         if (task->tk_rqstp) {
 798                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 799                                 __func__, status);
 800                 xprt_release(task);
 801         }
 802
 803         switch (status) {
 804         case -EAGAIN:   /* woken up; retry */
 805                 task->tk_action = call_reserve;
 806                 return;
 807         case -EIO:      /* probably a shutdown */
 808                 break;
 809         default:
 810                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 811                                 __func__, status);
 812                 break;
 813         }
 814         rpc_exit(task, status);
 815 }
 816
 817 /*
 818  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 819  *      (Note: buffer memory is freed in xprt_release).
 820  */
 821 static void
 822 call_allocate(struct rpc_task *task)
 823 {
 824         unsigned int slack = task->tk_msg.rpc_cred->cr_auth->au_cslack;
 825         struct rpc_rqst *req = task->tk_rqstp;
 826         struct rpc_xprt *xprt = task->tk_xprt;
 827         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 828
 829         dprint_status(task);
 830
 831         task->tk_status = 0;
 832         task->tk_action = call_bind;
 833
 834         if (req->rq_buffer)
 835                 return;
 836
 837         if (proc->p_proc != 0) {
 838                 BUG_ON(proc->p_arglen == 0);
 839                 if (proc->p_decode != NULL)
 840                         BUG_ON(proc->p_replen == 0);
 841         }
 842
 843         /*
 844          * Calculate the size (in quads) of the RPC call
 845          * and reply headers, and convert both values
 846          * to byte sizes.
 847          */
 848         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
 849         req->rq_callsize <<= 2;
 850         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
 851         req->rq_rcvsize <<= 2;
 852
 853         req->rq_buffer = xprt->ops->buf_alloc(task,
 854                                         req->rq_callsize + req->rq_rcvsize);
 855         if (req->rq_buffer != NULL)
 856                 return;
 857
 858         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 859
 860         if (RPC_IS_ASYNC(task) || !signalled()) {
 861                 task->tk_action = call_allocate;
 862                 rpc_delay(task, HZ>>4);
 863                 return;
 864         }
 865
 866         rpc_exit(task, -ERESTARTSYS);
 867 }
 868
 869 static inline int
 870 rpc_task_need_encode(struct rpc_task *task)
 871 {
 872         return task->tk_rqstp->rq_snd_buf.len == 0;
 873 }
 874
 875 static inline void
 876 rpc_task_force_reencode(struct rpc_task *task)
 877 {
 878         task->tk_rqstp->rq_snd_buf.len = 0;
 879 }
 880
 881 static inline void
 882 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
 883 {
 884         buf->head[0].iov_base = start;
 885         buf->head[0].iov_len = len;
 886         buf->tail[0].iov_len = 0;
 887         buf->page_len = 0;
 888         buf->flags = 0;
 889         buf->len = 0;
 890         buf->buflen = len;
 891 }
 892
 893 /*
 894  * 3.   Encode arguments of an RPC call
 895  */
 896 static void
 897 rpc_xdr_encode(struct rpc_task *task)
 898 {
 899         struct rpc_rqst *req = task->tk_rqstp;
 900         kxdrproc_t      encode;
 901         __be32          *p;
 902
 903         dprint_status(task);
 904
 905         rpc_xdr_buf_init(&req->rq_snd_buf,
 906                          req->rq_buffer,
 907                          req->rq_callsize);
 908         rpc_xdr_buf_init(&req->rq_rcv_buf,
 909                          (char *)req->rq_buffer + req->rq_callsize,
 910                          req->rq_rcvsize);
 911
 912         p = rpc_encode_header(task);
 913         if (p == NULL) {
 914                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
 915                 rpc_exit(task, -EIO);
 916                 return;
 917         }
 918
 919         encode = task->tk_msg.rpc_proc->p_encode;
 920         if (encode == NULL)
 921                 return;
 922
 923         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 924                         task->tk_msg.rpc_argp);
 925 }
 926
 927 /*
 928  * 4.   Get the server port number if not yet set
 929  */
 930 static void
 931 call_bind(struct rpc_task *task)
 932 {
 933         struct rpc_xprt *xprt = task->tk_xprt;
 934
 935         dprint_status(task);
 936
 937         task->tk_action = call_connect;
 938         if (!xprt_bound(xprt)) {
 939                 task->tk_action = call_bind_status;
 940                 task->tk_timeout = xprt->bind_timeout;
 941                 xprt->ops->rpcbind(task);
 942         }
 943 }
 944
 945 /*
 946  * 4a.  Sort out bind result
 947  */
 948 static void
 949 call_bind_status(struct rpc_task *task)
 950 {
 951         int status = -EIO;
 952
 953         if (task->tk_status >= 0) {
 954                 dprint_status(task);
 955                 task->tk_status = 0;
 956                 task->tk_action = call_connect;
 957                 return;
 958         }
 959
 960         switch (task->tk_status) {
 961         case -ENOMEM:
 962                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
 963                 rpc_delay(task, HZ >> 2);
 964                 goto retry_timeout;
 965         case -EACCES:
 966                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 967                                 "unavailable\n", task->tk_pid);
 968                 /* fail immediately if this is an RPC ping */
 969                 if (task->tk_msg.rpc_proc->p_proc == 0) {
 970                         status = -EOPNOTSUPP;
 971                         break;
 972                 }
 973                 rpc_delay(task, 3*HZ);
 974                 goto retry_timeout;
 975         case -ETIMEDOUT:
 976                 dprintk("RPC: %5u rpcbind request timed out\n",
 977                                 task->tk_pid);
 978                 goto retry_timeout;
 979         case -EPFNOSUPPORT:
 980                 /* server doesn't support any rpcbind version we know of */
 981                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 982                                 task->tk_pid);
 983                 break;
 984         case -EPROTONOSUPPORT:
 985                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
 986                                 task->tk_pid);
 987                 task->tk_status = 0;
 988                 task->tk_action = call_bind;
 989                 return;
 990         default:
 991                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 992                                 task->tk_pid, -task->tk_status);
 993         }
 994
 995         rpc_exit(task, status);
 996         return;
 997
 998 retry_timeout:
 999         task->tk_action = call_timeout;
1000 }
1001
1002 /*
1003  * 4b.  Connect to the RPC server
1004  */
1005 static void
1006 call_connect(struct rpc_task *task)
1007 {
1008         struct rpc_xprt *xprt = task->tk_xprt;
1009
1010         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1011                         task->tk_pid, xprt,
1012                         (xprt_connected(xprt) ? "is" : "is not"));
1013
1014         task->tk_action = call_transmit;
1015         if (!xprt_connected(xprt)) {
1016                 task->tk_action = call_connect_status;
1017                 if (task->tk_status < 0)
1018                         return;
1019                 xprt_connect(task);
1020         }
1021 }
1022
1023 /*
1024  * 4c.  Sort out connect result
1025  */
1026 static void
1027 call_connect_status(struct rpc_task *task)
1028 {
1029         struct rpc_clnt *clnt = task->tk_client;
1030         int status = task->tk_status;
1031
1032         dprint_status(task);
1033
1034         task->tk_status = 0;
1035         if (status >= 0 || status == -EAGAIN) {
1036                 clnt->cl_stats->netreconn++;
1037                 task->tk_action = call_transmit;
1038                 return;
1039         }
1040
1041         switch (status) {
1042                 /* if soft mounted, test if we've timed out */
1043         case -ETIMEDOUT:
1044                 task->tk_action = call_timeout;
1045                 break;
1046         default:
1047                 rpc_exit(task, -EIO);
1048         }
1049 }
1050
1051 /*
1052  * 5.   Transmit the RPC request, and wait for reply
1053  */
1054 static void
1055 call_transmit(struct rpc_task *task)
1056 {
1057         dprint_status(task);
1058
1059         task->tk_action = call_status;
1060         if (task->tk_status < 0)
1061                 return;
1062         task->tk_status = xprt_prepare_transmit(task);
1063         if (task->tk_status != 0)
1064                 return;
1065         task->tk_action = call_transmit_status;
1066         /* Encode here so that rpcsec_gss can use correct sequence number. */
1067         if (rpc_task_need_encode(task)) {
1068                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1069                 rpc_xdr_encode(task);
1070                 /* Did the encode result in an error condition? */
1071                 if (task->tk_status != 0) {
1072                         /* Was the error nonfatal? */
1073                         if (task->tk_status == -EAGAIN)
1074                                 rpc_delay(task, HZ >> 4);
1075                         else
1076                                 rpc_exit(task, task->tk_status);
1077                         return;
1078                 }
1079         }
1080         xprt_transmit(task);
1081         if (task->tk_status < 0)
1082                 return;
1083         /*
1084          * On success, ensure that we call xprt_end_transmit() before sleeping
1085          * in order to allow access to the socket to other RPC requests.
1086          */
1087         call_transmit_status(task);
1088         if (task->tk_msg.rpc_proc->p_decode != NULL)
1089                 return;
1090         task->tk_action = rpc_exit_task;
1091         rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
1092 }
1093
1094 /*
1095  * 5a.  Handle cleanup after a transmission
1096  */
1097 static void
1098 call_transmit_status(struct rpc_task *task)
1099 {
1100         task->tk_action = call_status;
1101         switch (task->tk_status) {
1102         case -EAGAIN:
1103                 break;
1104         default:
1105                 xprt_end_transmit(task);
1106                 /*
1107                  * Special cases: if we've been waiting on the
1108                  * socket's write_space() callback, or if the
1109                  * socket just returned a connection error,
1110                  * then hold onto the transport lock.
1111                  */
1112         case -ECONNREFUSED:
1113         case -ECONNRESET:
1114         case -ENOTCONN:
1115         case -EHOSTDOWN:
1116         case -EHOSTUNREACH:
1117         case -ENETUNREACH:
1118         case -EPIPE:
1119                 rpc_task_force_reencode(task);
1120         }
1121 }
1122
1123 /*
1124  * 6.   Sort out the RPC call status
1125  */
1126 static void
1127 call_status(struct rpc_task *task)
1128 {
1129         struct rpc_clnt *clnt = task->tk_client;
1130         struct rpc_rqst *req = task->tk_rqstp;
1131         int             status;
1132
1133         if (req->rq_received > 0 && !req->rq_bytes_sent)
1134                 task->tk_status = req->rq_received;
1135
1136         dprint_status(task);
1137
1138         status = task->tk_status;
1139         if (status >= 0) {
1140                 task->tk_action = call_decode;
1141                 return;
1142         }
1143
1144         task->tk_status = 0;
1145         switch(status) {
1146         case -EHOSTDOWN:
1147         case -EHOSTUNREACH:
1148         case -ENETUNREACH:
1149                 /*
1150                  * Delay any retries for 3 seconds, then handle as if it
1151                  * were a timeout.
1152                  */
1153                 rpc_delay(task, 3*HZ);
1154         case -ETIMEDOUT:
1155                 task->tk_action = call_timeout;
1156                 if (task->tk_client->cl_discrtry)
1157                         xprt_conditional_disconnect(task->tk_xprt,
1158                                         req->rq_connect_cookie);
1159                 break;
1160         case -ECONNRESET:
1161         case -ECONNREFUSED:
1162                 rpc_force_rebind(clnt);
1163                 rpc_delay(task, 3*HZ);
1164         case -EPIPE:
1165         case -ENOTCONN:
1166                 task->tk_action = call_bind;
1167                 break;
1168         case -EAGAIN:
1169                 task->tk_action = call_transmit;
1170                 break;
1171         case -EIO:
1172                 /* shutdown or soft timeout */
1173                 rpc_exit(task, status);
1174                 break;
1175         default:
1176                 if (clnt->cl_chatty)
1177                         printk("%s: RPC call returned error %d\n",
1178                                clnt->cl_protname, -status);
1179                 rpc_exit(task, status);
1180         }
1181 }
1182
1183 /*
1184  * 6a.  Handle RPC timeout
1185  *      We do not release the request slot, so we keep using the
1186  *      same XID for all retransmits.
1187  */
1188 static void
1189 call_timeout(struct rpc_task *task)
1190 {
1191         struct rpc_clnt *clnt = task->tk_client;
1192
1193         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1194                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1195                 goto retry;
1196         }
1197
1198         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1199         task->tk_timeouts++;
1200
1201         if (RPC_IS_SOFT(task)) {
1202                 if (clnt->cl_chatty)
1203                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1204                                 clnt->cl_protname, clnt->cl_server);
1205                 rpc_exit(task, -EIO);
1206                 return;
1207         }
1208
1209         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1210                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1211                 if (clnt->cl_chatty)
1212                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1213                         clnt->cl_protname, clnt->cl_server);
1214         }
1215         rpc_force_rebind(clnt);
1216         /*
1217          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1218          * event? RFC2203 requires the server to drop all such requests.
1219          */
1220         rpcauth_invalcred(task);
1221
1222 retry:
1223         clnt->cl_stats->rpcretrans++;
1224         task->tk_action = call_bind;
1225         task->tk_status = 0;
1226 }
1227
1228 /*
1229  * 7.   Decode the RPC reply
1230  */
1231 static void
1232 call_decode(struct rpc_task *task)
1233 {
1234         struct rpc_clnt *clnt = task->tk_client;
1235         struct rpc_rqst *req = task->tk_rqstp;
1236         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1237         __be32          *p;
1238
1239         dprintk("RPC: %5u call_decode (status %d)\n",
1240                         task->tk_pid, task->tk_status);
1241
1242         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1243                 if (clnt->cl_chatty)
1244                         printk(KERN_NOTICE "%s: server %s OK\n",
1245                                 clnt->cl_protname, clnt->cl_server);
1246                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1247         }
1248
1249         /*
1250          * Ensure that we see all writes made by xprt_complete_rqst()
1251          * before it changed req->rq_received.
1252          */
1253         smp_rmb();
1254         req->rq_rcv_buf.len = req->rq_private_buf.len;
1255
1256         /* Check that the softirq receive buffer is valid */
1257         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1258                                 sizeof(req->rq_rcv_buf)) != 0);
1259
1260         if (req->rq_rcv_buf.len < 12) {
1261                 if (!RPC_IS_SOFT(task)) {
1262                         task->tk_action = call_bind;
1263                         clnt->cl_stats->rpcretrans++;
1264                         goto out_retry;
1265                 }
1266                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1267                                 clnt->cl_protname, task->tk_status);
1268                 task->tk_action = call_timeout;
1269                 goto out_retry;
1270         }
1271
1272         p = rpc_verify_header(task);
1273         if (IS_ERR(p)) {
1274                 if (p == ERR_PTR(-EAGAIN))
1275                         goto out_retry;
1276                 return;
1277         }
1278
1279         task->tk_action = rpc_exit_task;
1280
1281         if (decode) {
1282                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1283                                                       task->tk_msg.rpc_resp);
1284         }
1285         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1286                         task->tk_status);
1287         return;
1288 out_retry:
1289         task->tk_status = 0;
1290         /* Note: rpc_verify_header() may have freed the RPC slot */
1291         if (task->tk_rqstp == req) {
1292                 req->rq_received = req->rq_rcv_buf.len = 0;
1293                 if (task->tk_client->cl_discrtry)
1294                         xprt_conditional_disconnect(task->tk_xprt,
1295                                         req->rq_connect_cookie);
1296         }
1297 }
1298
1299 /*
1300  * 8.   Refresh the credentials if rejected by the server
1301  */
1302 static void
1303 call_refresh(struct rpc_task *task)
1304 {
1305         dprint_status(task);
1306
1307         task->tk_action = call_refreshresult;
1308         task->tk_status = 0;
1309         task->tk_client->cl_stats->rpcauthrefresh++;
1310         rpcauth_refreshcred(task);
1311 }
1312
1313 /*
1314  * 8a.  Process the results of a credential refresh
1315  */
1316 static void
1317 call_refreshresult(struct rpc_task *task)
1318 {
1319         int status = task->tk_status;
1320
1321         dprint_status(task);
1322
1323         task->tk_status = 0;
1324         task->tk_action = call_reserve;
1325         if (status >= 0 && rpcauth_uptodatecred(task))
1326                 return;
1327         if (status == -EACCES) {
1328                 rpc_exit(task, -EACCES);
1329                 return;
1330         }
1331         task->tk_action = call_refresh;
1332         if (status != -ETIMEDOUT)
1333                 rpc_delay(task, 3*HZ);
1334         return;
1335 }
1336
1337 static __be32 *
1338 rpc_encode_header(struct rpc_task *task)
1339 {
1340         struct rpc_clnt *clnt = task->tk_client;
1341         struct rpc_rqst *req = task->tk_rqstp;
1342         __be32          *p = req->rq_svec[0].iov_base;
1343
1344         /* FIXME: check buffer size? */
1345
1346         p = xprt_skip_transport_header(task->tk_xprt, p);
1347         *p++ = req->rq_xid;             /* XID */
1348         *p++ = htonl(RPC_CALL);         /* CALL */
1349         *p++ = htonl(RPC_VERSION);      /* RPC version */
1350         *p++ = htonl(clnt->cl_prog);    /* program number */
1351         *p++ = htonl(clnt->cl_vers);    /* program version */
1352         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1353         p = rpcauth_marshcred(task, p);
1354         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1355         return p;
1356 }
1357
1358 static __be32 *
1359 rpc_verify_header(struct rpc_task *task)
1360 {
1361         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1362         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1363         __be32  *p = iov->iov_base;
1364         u32 n;
1365         int error = -EACCES;
1366
1367         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1368                 /* RFC-1014 says that the representation of XDR data must be a
1369                  * multiple of four bytes
1370                  * - if it isn't pointer subtraction in the NFS client may give
1371                  *   undefined results
1372                  */
1373                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1374                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
1375                        task->tk_rqstp->rq_rcv_buf.len);
1376                 goto out_eio;
1377         }
1378         if ((len -= 3) < 0)
1379                 goto out_overflow;
1380         p += 1; /* skip XID */
1381
1382         if ((n = ntohl(*p++)) != RPC_REPLY) {
1383                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1384                                 task->tk_pid, __func__, n);
1385                 goto out_garbage;
1386         }
1387         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1388                 if (--len < 0)
1389                         goto out_overflow;
1390                 switch ((n = ntohl(*p++))) {
1391                         case RPC_AUTH_ERROR:
1392                                 break;
1393                         case RPC_MISMATCH:
1394                                 dprintk("RPC: %5u %s: RPC call version "
1395                                                 "mismatch!\n",
1396                                                 task->tk_pid, __func__);
1397                                 error = -EPROTONOSUPPORT;
1398                                 goto out_err;
1399                         default:
1400                                 dprintk("RPC: %5u %s: RPC call rejected, "
1401                                                 "unknown error: %x\n",
1402                                                 task->tk_pid, __func__, n);
1403                                 goto out_eio;
1404                 }
1405                 if (--len < 0)
1406                         goto out_overflow;
1407                 switch ((n = ntohl(*p++))) {
1408                 case RPC_AUTH_REJECTEDCRED:
1409                 case RPC_AUTH_REJECTEDVERF:
1410                 case RPCSEC_GSS_CREDPROBLEM:
1411                 case RPCSEC_GSS_CTXPROBLEM:
1412                         if (!task->tk_cred_retry)
1413                                 break;
1414                         task->tk_cred_retry--;
1415                         dprintk("RPC: %5u %s: retry stale creds\n",
1416                                         task->tk_pid, __func__);
1417                         rpcauth_invalcred(task);
1418                         /* Ensure we obtain a new XID! */
1419                         xprt_release(task);
1420                         task->tk_action = call_refresh;
1421                         goto out_retry;
1422                 case RPC_AUTH_BADCRED:
1423                 case RPC_AUTH_BADVERF:
1424                         /* possibly garbled cred/verf? */
1425                         if (!task->tk_garb_retry)
1426                                 break;
1427                         task->tk_garb_retry--;
1428                         dprintk("RPC: %5u %s: retry garbled creds\n",
1429                                         task->tk_pid, __func__);
1430                         task->tk_action = call_bind;
1431                         goto out_retry;
1432                 case RPC_AUTH_TOOWEAK:
1433                         printk(KERN_NOTICE "RPC: server %s requires stronger "
1434                                "authentication.\n", task->tk_client->cl_server);
1435                         break;
1436                 default:
1437                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1438                                         task->tk_pid, __func__, n);
1439                         error = -EIO;
1440                 }
1441                 dprintk("RPC: %5u %s: call rejected %d\n",
1442                                 task->tk_pid, __func__, n);
1443                 goto out_err;
1444         }
1445         if (!(p = rpcauth_checkverf(task, p))) {
1446                 dprintk("RPC: %5u %s: auth check failed\n",
1447                                 task->tk_pid, __func__);
1448                 goto out_garbage;               /* bad verifier, retry */
1449         }
1450         len = p - (__be32 *)iov->iov_base - 1;
1451         if (len < 0)
1452                 goto out_overflow;
1453         switch ((n = ntohl(*p++))) {
1454         case RPC_SUCCESS:
1455                 return p;
1456         case RPC_PROG_UNAVAIL:
1457                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1458                                 task->tk_pid, __func__,
1459                                 (unsigned int)task->tk_client->cl_prog,
1460                                 task->tk_client->cl_server);
1461                 error = -EPFNOSUPPORT;
1462                 goto out_err;
1463         case RPC_PROG_MISMATCH:
1464                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1465                                 "server %s\n", task->tk_pid, __func__,
1466                                 (unsigned int)task->tk_client->cl_prog,
1467                                 (unsigned int)task->tk_client->cl_vers,
1468                                 task->tk_client->cl_server);
1469                 error = -EPROTONOSUPPORT;
1470                 goto out_err;
1471         case RPC_PROC_UNAVAIL:
1472                 dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
1473                                 "version %u on server %s\n",
1474                                 task->tk_pid, __func__,
1475                                 rpc_proc_name(task),
1476                                 task->tk_client->cl_prog,
1477                                 task->tk_client->cl_vers,
1478                                 task->tk_client->cl_server);
1479                 error = -EOPNOTSUPP;
1480                 goto out_err;
1481         case RPC_GARBAGE_ARGS:
1482                 dprintk("RPC: %5u %s: server saw garbage\n",
1483                                 task->tk_pid, __func__);
1484                 break;                  /* retry */
1485         default:
1486                 dprintk("RPC: %5u %s: server accept status: %x\n",
1487                                 task->tk_pid, __func__, n);
1488                 /* Also retry */
1489         }
1490
1491 out_garbage:
1492         task->tk_client->cl_stats->rpcgarbage++;
1493         if (task->tk_garb_retry) {
1494                 task->tk_garb_retry--;
1495                 dprintk("RPC: %5u %s: retrying\n",
1496                                 task->tk_pid, __func__);
1497                 task->tk_action = call_bind;
1498 out_retry:
1499                 return ERR_PTR(-EAGAIN);
1500         }
1501 out_eio:
1502         error = -EIO;
1503 out_err:
1504         rpc_exit(task, error);
1505         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1506                         __func__, error);
1507         return ERR_PTR(error);
1508 out_overflow:
1509         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1510                         __func__);
1511         goto out_garbage;
1512 }
1513
1514 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1515 {
1516         return 0;
1517 }
1518
1519 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1520 {
1521         return 0;
1522 }
1523
1524 static struct rpc_procinfo rpcproc_null = {
1525         .p_encode = rpcproc_encode_null,
1526         .p_decode = rpcproc_decode_null,
1527 };
1528
1529 static int rpc_ping(struct rpc_clnt *clnt, int flags)
1530 {
1531         struct rpc_message msg = {
1532                 .rpc_proc = &rpcproc_null,
1533         };
1534         int err;
1535         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1536         err = rpc_call_sync(clnt, &msg, flags);
1537         put_rpccred(msg.rpc_cred);
1538         return err;
1539 }
1540
1541 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1542 {
1543         struct rpc_message msg = {
1544                 .rpc_proc = &rpcproc_null,
1545                 .rpc_cred = cred,
1546         };
1547         struct rpc_task_setup task_setup_data = {
1548                 .rpc_client = clnt,
1549                 .rpc_message = &msg,
1550                 .callback_ops = &rpc_default_ops,
1551                 .flags = flags,
1552         };
1553         return rpc_run_task(&task_setup_data);
1554 }
1555 EXPORT_SYMBOL_GPL(rpc_call_null);
1556
1557 #ifdef RPC_DEBUG
1558 static void rpc_show_header(void)
1559 {
1560         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
1561                 "-timeout ---ops--\n");
1562 }
1563
1564 static void rpc_show_task(const struct rpc_clnt *clnt,
1565                           const struct rpc_task *task)
1566 {
1567         const char *rpc_waitq = "none";
1568         char *p, action[KSYM_SYMBOL_LEN];
1569
1570         if (RPC_IS_QUEUED(task))
1571                 rpc_waitq = rpc_qname(task->tk_waitqueue);
1572
1573         /* map tk_action pointer to a function name; then trim off
1574          * the "+0x0 [sunrpc]" */
1575         sprint_symbol(action, (unsigned long)task->tk_action);
1576         p = strchr(action, '+');
1577         if (p)
1578                 *p = '\0';
1579
1580         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%s q:%s\n",
1581                 task->tk_pid, task->tk_flags, task->tk_status,
1582                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
1583                 clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
1584                 action, rpc_waitq);
1585 }
1586
1587 void rpc_show_tasks(void)
1588 {
1589         struct rpc_clnt *clnt;
1590         struct rpc_task *task;
1591         int header = 0;
1592
1593         spin_lock(&rpc_client_lock);
1594         list_for_each_entry(clnt, &all_clients, cl_clients) {
1595                 spin_lock(&clnt->cl_lock);
1596                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
1597                         if (!header) {
1598                                 rpc_show_header();
1599                                 header++;
1600                         }
1601                         rpc_show_task(clnt, task);
1602                 }
1603                 spin_unlock(&clnt->cl_lock);
1604         }
1605         spin_unlock(&rpc_client_lock);
1606 }
1607 #endif