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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/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/utsname.h>
  32 #include <linux/workqueue.h>
  33
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/rpc_pipe_fs.h>
  36 #include <linux/sunrpc/metrics.h>
  37
  38
  39 #ifdef RPC_DEBUG
  40 # define RPCDBG_FACILITY        RPCDBG_CALL
  41 #endif
  42
  43 #define dprint_status(t)                                        \
  44         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  45                         __FUNCTION__, t->tk_status)
  46
  47 /*
  48  * All RPC clients are linked into this list
  49  */
  50 static LIST_HEAD(all_clients);
  51 static DEFINE_SPINLOCK(rpc_client_lock);
  52
  53 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  54
  55
  56 static void     call_start(struct rpc_task *task);
  57 static void     call_reserve(struct rpc_task *task);
  58 static void     call_reserveresult(struct rpc_task *task);
  59 static void     call_allocate(struct rpc_task *task);
  60 static void     call_encode(struct rpc_task *task);
  61 static void     call_decode(struct rpc_task *task);
  62 static void     call_bind(struct rpc_task *task);
  63 static void     call_bind_status(struct rpc_task *task);
  64 static void     call_transmit(struct rpc_task *task);
  65 static void     call_status(struct rpc_task *task);
  66 static void     call_transmit_status(struct rpc_task *task);
  67 static void     call_refresh(struct rpc_task *task);
  68 static void     call_refreshresult(struct rpc_task *task);
  69 static void     call_timeout(struct rpc_task *task);
  70 static void     call_connect(struct rpc_task *task);
  71 static void     call_connect_status(struct rpc_task *task);
  72 static __be32 * call_header(struct rpc_task *task);
  73 static __be32 * call_verify(struct rpc_task *task);
  74
  75 static int      rpc_ping(struct rpc_clnt *clnt, int flags);
  76
  77 static void rpc_register_client(struct rpc_clnt *clnt)
  78 {
  79         spin_lock(&rpc_client_lock);
  80         list_add(&clnt->cl_clients, &all_clients);
  81         spin_unlock(&rpc_client_lock);
  82 }
  83
  84 static void rpc_unregister_client(struct rpc_clnt *clnt)
  85 {
  86         spin_lock(&rpc_client_lock);
  87         list_del(&clnt->cl_clients);
  88         spin_unlock(&rpc_client_lock);
  89 }
  90
  91 static int
  92 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  93 {
  94         static uint32_t clntid;
  95         int error;
  96
  97         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  98         clnt->cl_dentry = ERR_PTR(-ENOENT);
  99         if (dir_name == NULL)
 100                 return 0;
 101
 102         clnt->cl_vfsmnt = rpc_get_mount();
 103         if (IS_ERR(clnt->cl_vfsmnt))
 104                 return PTR_ERR(clnt->cl_vfsmnt);
 105
 106         for (;;) {
 107                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
 108                                 "%s/clnt%x", dir_name,
 109                                 (unsigned int)clntid++);
 110                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
 111                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
 112                 if (!IS_ERR(clnt->cl_dentry))
 113                         return 0;
 114                 error = PTR_ERR(clnt->cl_dentry);
 115                 if (error != -EEXIST) {
 116                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
 117                                         clnt->cl_pathname, error);
 118                         rpc_put_mount();
 119                         return error;
 120                 }
 121         }
 122 }
 123
 124 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 125 {
 126         struct rpc_version      *version;
 127         struct rpc_clnt         *clnt = NULL;
 128         struct rpc_auth         *auth;
 129         int err;
 130         size_t len;
 131
 132         /* sanity check the name before trying to print it */
 133         err = -EINVAL;
 134         len = strlen(servname);
 135         if (len > RPC_MAXNETNAMELEN)
 136                 goto out_no_rpciod;
 137         len++;
 138
 139         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 140                         program->name, servname, xprt);
 141
 142         err = rpciod_up();
 143         if (err)
 144                 goto out_no_rpciod;
 145         err = -EINVAL;
 146         if (!xprt)
 147                 goto out_no_xprt;
 148         if (vers >= program->nrvers || !(version = program->version[vers]))
 149                 goto out_err;
 150
 151         err = -ENOMEM;
 152         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 153         if (!clnt)
 154                 goto out_err;
 155         clnt->cl_parent = clnt;
 156
 157         clnt->cl_server = clnt->cl_inline_name;
 158         if (len > sizeof(clnt->cl_inline_name)) {
 159                 char *buf = kmalloc(len, GFP_KERNEL);
 160                 if (buf != 0)
 161                         clnt->cl_server = buf;
 162                 else
 163                         len = sizeof(clnt->cl_inline_name);
 164         }
 165         strlcpy(clnt->cl_server, servname, len);
 166
 167         clnt->cl_xprt     = xprt;
 168         clnt->cl_procinfo = version->procs;
 169         clnt->cl_maxproc  = version->nrprocs;
 170         clnt->cl_protname = program->name;
 171         clnt->cl_prog     = program->number;
 172         clnt->cl_vers     = version->number;
 173         clnt->cl_stats    = program->stats;
 174         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 175         err = -ENOMEM;
 176         if (clnt->cl_metrics == NULL)
 177                 goto out_no_stats;
 178         clnt->cl_program  = program;
 179         INIT_LIST_HEAD(&clnt->cl_tasks);
 180         spin_lock_init(&clnt->cl_lock);
 181
 182         if (!xprt_bound(clnt->cl_xprt))
 183                 clnt->cl_autobind = 1;
 184
 185         clnt->cl_rtt = &clnt->cl_rtt_default;
 186         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 187
 188         kref_init(&clnt->cl_kref);
 189
 190         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 191         if (err < 0)
 192                 goto out_no_path;
 193
 194         auth = rpcauth_create(flavor, clnt);
 195         if (IS_ERR(auth)) {
 196                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 197                                 flavor);
 198                 err = PTR_ERR(auth);
 199                 goto out_no_auth;
 200         }
 201
 202         /* save the nodename */
 203         clnt->cl_nodelen = strlen(utsname()->nodename);
 204         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 205                 clnt->cl_nodelen = UNX_MAXNODENAME;
 206         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 207         rpc_register_client(clnt);
 208         return clnt;
 209
 210 out_no_auth:
 211         if (!IS_ERR(clnt->cl_dentry)) {
 212                 rpc_rmdir(clnt->cl_dentry);
 213                 rpc_put_mount();
 214         }
 215 out_no_path:
 216         rpc_free_iostats(clnt->cl_metrics);
 217 out_no_stats:
 218         if (clnt->cl_server != clnt->cl_inline_name)
 219                 kfree(clnt->cl_server);
 220         kfree(clnt);
 221 out_err:
 222         xprt_put(xprt);
 223 out_no_xprt:
 224         rpciod_down();
 225 out_no_rpciod:
 226         return ERR_PTR(err);
 227 }
 228
 229 /*
 230  * rpc_create - create an RPC client and transport with one call
 231  * @args: rpc_clnt create argument structure
 232  *
 233  * Creates and initializes an RPC transport and an RPC client.
 234  *
 235  * It can ping the server in order to determine if it is up, and to see if
 236  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 237  * this behavior so asynchronous tasks can also use rpc_create.
 238  */
 239 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 240 {
 241         struct rpc_xprt *xprt;
 242         struct rpc_clnt *clnt;
 243         struct xprt_create xprtargs = {
 244                 .ident = args->protocol,
 245                 .srcaddr = args->saddress,
 246                 .dstaddr = args->address,
 247                 .addrlen = args->addrsize,
 248                 .timeout = args->timeout
 249         };
 250         char servername[20];
 251
 252         xprt = xprt_create_transport(&xprtargs);
 253         if (IS_ERR(xprt))
 254                 return (struct rpc_clnt *)xprt;
 255
 256         /*
 257          * If the caller chooses not to specify a hostname, whip
 258          * up a string representation of the passed-in address.
 259          */
 260         if (args->servername == NULL) {
 261                 struct sockaddr_in *addr =
 262                                         (struct sockaddr_in *) args->address;
 263                 snprintf(servername, sizeof(servername), NIPQUAD_FMT,
 264                         NIPQUAD(addr->sin_addr.s_addr));
 265                 args->servername = servername;
 266         }
 267
 268         /*
 269          * By default, kernel RPC client connects from a reserved port.
 270          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 271          * but it is always enabled for rpciod, which handles the connect
 272          * operation.
 273          */
 274         xprt->resvport = 1;
 275         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 276                 xprt->resvport = 0;
 277
 278         clnt = rpc_new_client(xprt, args->servername, args->program,
 279                                 args->version, args->authflavor);
 280         if (IS_ERR(clnt))
 281                 return clnt;
 282
 283         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 284                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 285                 if (err != 0) {
 286                         rpc_shutdown_client(clnt);
 287                         return ERR_PTR(err);
 288                 }
 289         }
 290
 291         clnt->cl_softrtry = 1;
 292         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 293                 clnt->cl_softrtry = 0;
 294
 295         if (args->flags & RPC_CLNT_CREATE_INTR)
 296                 clnt->cl_intr = 1;
 297         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 298                 clnt->cl_autobind = 1;
 299         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 300                 clnt->cl_discrtry = 1;
 301
 302         return clnt;
 303 }
 304 EXPORT_SYMBOL_GPL(rpc_create);
 305
 306 /*
 307  * This function clones the RPC client structure. It allows us to share the
 308  * same transport while varying parameters such as the authentication
 309  * flavour.
 310  */
 311 struct rpc_clnt *
 312 rpc_clone_client(struct rpc_clnt *clnt)
 313 {
 314         struct rpc_clnt *new;
 315         int err = -ENOMEM;
 316
 317         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 318         if (!new)
 319                 goto out_no_clnt;
 320         new->cl_parent = clnt;
 321         /* Turn off autobind on clones */
 322         new->cl_autobind = 0;
 323         INIT_LIST_HEAD(&new->cl_tasks);
 324         spin_lock_init(&new->cl_lock);
 325         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 326         new->cl_metrics = rpc_alloc_iostats(clnt);
 327         if (new->cl_metrics == NULL)
 328                 goto out_no_stats;
 329         kref_init(&new->cl_kref);
 330         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 331         if (err != 0)
 332                 goto out_no_path;
 333         if (new->cl_auth)
 334                 atomic_inc(&new->cl_auth->au_count);
 335         xprt_get(clnt->cl_xprt);
 336         kref_get(&clnt->cl_kref);
 337         rpc_register_client(new);
 338         rpciod_up();
 339         return new;
 340 out_no_path:
 341         rpc_free_iostats(new->cl_metrics);
 342 out_no_stats:
 343         kfree(new);
 344 out_no_clnt:
 345         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
 346         return ERR_PTR(err);
 347 }
 348 EXPORT_SYMBOL_GPL(rpc_clone_client);
 349
 350 /*
 351  * Properly shut down an RPC client, terminating all outstanding
 352  * requests.
 353  */
 354 void rpc_shutdown_client(struct rpc_clnt *clnt)
 355 {
 356         dprintk("RPC:       shutting down %s client for %s\n",
 357                         clnt->cl_protname, clnt->cl_server);
 358
 359         while (!list_empty(&clnt->cl_tasks)) {
 360                 rpc_killall_tasks(clnt);
 361                 wait_event_timeout(destroy_wait,
 362                         list_empty(&clnt->cl_tasks), 1*HZ);
 363         }
 364
 365         rpc_release_client(clnt);
 366 }
 367 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 368
 369 /*
 370  * Free an RPC client
 371  */
 372 static void
 373 rpc_free_client(struct kref *kref)
 374 {
 375         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 376
 377         dprintk("RPC:       destroying %s client for %s\n",
 378                         clnt->cl_protname, clnt->cl_server);
 379         if (!IS_ERR(clnt->cl_dentry)) {
 380                 rpc_rmdir(clnt->cl_dentry);
 381                 rpc_put_mount();
 382         }
 383         if (clnt->cl_parent != clnt) {
 384                 rpc_release_client(clnt->cl_parent);
 385                 goto out_free;
 386         }
 387         if (clnt->cl_server != clnt->cl_inline_name)
 388                 kfree(clnt->cl_server);
 389 out_free:
 390         rpc_unregister_client(clnt);
 391         rpc_free_iostats(clnt->cl_metrics);
 392         clnt->cl_metrics = NULL;
 393         xprt_put(clnt->cl_xprt);
 394         rpciod_down();
 395         kfree(clnt);
 396 }
 397
 398 /*
 399  * Free an RPC client
 400  */
 401 static void
 402 rpc_free_auth(struct kref *kref)
 403 {
 404         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 405
 406         if (clnt->cl_auth == NULL) {
 407                 rpc_free_client(kref);
 408                 return;
 409         }
 410
 411         /*
 412          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 413          *       release remaining GSS contexts. This mechanism ensures
 414          *       that it can do so safely.
 415          */
 416         kref_init(kref);
 417         rpcauth_release(clnt->cl_auth);
 418         clnt->cl_auth = NULL;
 419         kref_put(kref, rpc_free_client);
 420 }
 421
 422 /*
 423  * Release reference to the RPC client
 424  */
 425 void
 426 rpc_release_client(struct rpc_clnt *clnt)
 427 {
 428         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 429
 430         if (list_empty(&clnt->cl_tasks))
 431                 wake_up(&destroy_wait);
 432         kref_put(&clnt->cl_kref, rpc_free_auth);
 433 }
 434
 435 /**
 436  * rpc_bind_new_program - bind a new RPC program to an existing client
 437  * @old - old rpc_client
 438  * @program - rpc program to set
 439  * @vers - rpc program version
 440  *
 441  * Clones the rpc client and sets up a new RPC program. This is mainly
 442  * of use for enabling different RPC programs to share the same transport.
 443  * The Sun NFSv2/v3 ACL protocol can do this.
 444  */
 445 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 446                                       struct rpc_program *program,
 447                                       u32 vers)
 448 {
 449         struct rpc_clnt *clnt;
 450         struct rpc_version *version;
 451         int err;
 452
 453         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 454         version = program->version[vers];
 455         clnt = rpc_clone_client(old);
 456         if (IS_ERR(clnt))
 457                 goto out;
 458         clnt->cl_procinfo = version->procs;
 459         clnt->cl_maxproc  = version->nrprocs;
 460         clnt->cl_protname = program->name;
 461         clnt->cl_prog     = program->number;
 462         clnt->cl_vers     = version->number;
 463         clnt->cl_stats    = program->stats;
 464         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 465         if (err != 0) {
 466                 rpc_shutdown_client(clnt);
 467                 clnt = ERR_PTR(err);
 468         }
 469 out:
 470         return clnt;
 471 }
 472 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 473
 474 /*
 475  * Default callback for async RPC calls
 476  */
 477 static void
 478 rpc_default_callback(struct rpc_task *task, void *data)
 479 {
 480 }
 481
 482 static const struct rpc_call_ops rpc_default_ops = {
 483         .rpc_call_done = rpc_default_callback,
 484 };
 485
 486 /*
 487  *      Export the signal mask handling for synchronous code that
 488  *      sleeps on RPC calls
 489  */
 490 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 491
 492 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 493 {
 494         unsigned long   sigallow = sigmask(SIGKILL);
 495         sigset_t sigmask;
 496
 497         /* Block all signals except those listed in sigallow */
 498         if (intr)
 499                 sigallow |= RPC_INTR_SIGNALS;
 500         siginitsetinv(&sigmask, sigallow);
 501         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 502 }
 503
 504 static void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 505 {
 506         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 507 }
 508
 509 static void rpc_restore_sigmask(sigset_t *oldset)
 510 {
 511         sigprocmask(SIG_SETMASK, oldset, NULL);
 512 }
 513
 514 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 515 {
 516         rpc_save_sigmask(oldset, clnt->cl_intr);
 517 }
 518 EXPORT_SYMBOL_GPL(rpc_clnt_sigmask);
 519
 520 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 521 {
 522         rpc_restore_sigmask(oldset);
 523 }
 524 EXPORT_SYMBOL_GPL(rpc_clnt_sigunmask);
 525
 526 /**
 527  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 528  * @task_setup_data: pointer to task initialisation data
 529  */
 530 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 531 {
 532         struct rpc_task *task, *ret;
 533         sigset_t oldset;
 534
 535         task = rpc_new_task(task_setup_data);
 536         if (task == NULL) {
 537                 rpc_release_calldata(task_setup_data->callback_ops,
 538                                 task_setup_data->callback_data);
 539                 ret = ERR_PTR(-ENOMEM);
 540                 goto out;
 541         }
 542
 543         if (task->tk_status != 0) {
 544                 ret = ERR_PTR(task->tk_status);
 545                 rpc_put_task(task);
 546                 goto out;
 547         }
 548         atomic_inc(&task->tk_count);
 549         /* Mask signals on synchronous RPC calls and RPCSEC_GSS upcalls */
 550         rpc_task_sigmask(task, &oldset);
 551         rpc_execute(task);
 552         rpc_restore_sigmask(&oldset);
 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, 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  * @ops: RPC call ops
 593  * @data: user call data
 594  */
 595 int
 596 rpc_call_async(struct rpc_clnt *clnt, 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  * @size: 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 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 651 {
 652         struct rpc_xprt *xprt = clnt->cl_xprt;
 653
 654         if (xprt->address_strings[format] != NULL)
 655                 return xprt->address_strings[format];
 656         else
 657                 return "unprintable";
 658 }
 659 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 660
 661 void
 662 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 663 {
 664         struct rpc_xprt *xprt = clnt->cl_xprt;
 665         if (xprt->ops->set_buffer_size)
 666                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 667 }
 668 EXPORT_SYMBOL_GPL(rpc_setbufsize);
 669
 670 /*
 671  * Return size of largest payload RPC client can support, in bytes
 672  *
 673  * For stream transports, this is one RPC record fragment (see RFC
 674  * 1831), as we don't support multi-record requests yet.  For datagram
 675  * transports, this is the size of an IP packet minus the IP, UDP, and
 676  * RPC header sizes.
 677  */
 678 size_t rpc_max_payload(struct rpc_clnt *clnt)
 679 {
 680         return clnt->cl_xprt->max_payload;
 681 }
 682 EXPORT_SYMBOL_GPL(rpc_max_payload);
 683
 684 /**
 685  * rpc_force_rebind - force transport to check that remote port is unchanged
 686  * @clnt: client to rebind
 687  *
 688  */
 689 void rpc_force_rebind(struct rpc_clnt *clnt)
 690 {
 691         if (clnt->cl_autobind)
 692                 xprt_clear_bound(clnt->cl_xprt);
 693 }
 694 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 695
 696 /*
 697  * Restart an (async) RPC call. Usually called from within the
 698  * exit handler.
 699  */
 700 void
 701 rpc_restart_call(struct rpc_task *task)
 702 {
 703         if (RPC_ASSASSINATED(task))
 704                 return;
 705
 706         task->tk_action = call_start;
 707 }
 708 EXPORT_SYMBOL_GPL(rpc_restart_call);
 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 %d (%s)\n", task->tk_pid,
 722                         clnt->cl_protname, clnt->cl_vers,
 723                         task->tk_msg.rpc_proc->p_proc,
 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                                 __FUNCTION__, 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                                 __FUNCTION__, 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                                 __FUNCTION__, 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 call_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         /* Encode header and provided arguments */
 897         encode = task->tk_msg.rpc_proc->p_encode;
 898         if (!(p = call_header(task))) {
 899                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 900                 rpc_exit(task, -EIO);
 901                 return;
 902         }
 903         if (encode == NULL)
 904                 return;
 905
 906         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 907                         task->tk_msg.rpc_argp);
 908         if (task->tk_status == -ENOMEM) {
 909                 /* XXX: Is this sane? */
 910                 rpc_delay(task, 3*HZ);
 911                 task->tk_status = -EAGAIN;
 912         }
 913 }
 914
 915 /*
 916  * 4.   Get the server port number if not yet set
 917  */
 918 static void
 919 call_bind(struct rpc_task *task)
 920 {
 921         struct rpc_xprt *xprt = task->tk_xprt;
 922
 923         dprint_status(task);
 924
 925         task->tk_action = call_connect;
 926         if (!xprt_bound(xprt)) {
 927                 task->tk_action = call_bind_status;
 928                 task->tk_timeout = xprt->bind_timeout;
 929                 xprt->ops->rpcbind(task);
 930         }
 931 }
 932
 933 /*
 934  * 4a.  Sort out bind result
 935  */
 936 static void
 937 call_bind_status(struct rpc_task *task)
 938 {
 939         int status = -EIO;
 940
 941         if (task->tk_status >= 0) {
 942                 dprint_status(task);
 943                 task->tk_status = 0;
 944                 task->tk_action = call_connect;
 945                 return;
 946         }
 947
 948         switch (task->tk_status) {
 949         case -EAGAIN:
 950                 dprintk("RPC: %5u rpcbind waiting for another request "
 951                                 "to finish\n", task->tk_pid);
 952                 /* avoid busy-waiting here -- could be a network outage. */
 953                 rpc_delay(task, 5*HZ);
 954                 goto retry_timeout;
 955         case -EACCES:
 956                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 957                                 "unavailable\n", task->tk_pid);
 958                 /* fail immediately if this is an RPC ping */
 959                 if (task->tk_msg.rpc_proc->p_proc == 0) {
 960                         status = -EOPNOTSUPP;
 961                         break;
 962                 }
 963                 rpc_delay(task, 3*HZ);
 964                 goto retry_timeout;
 965         case -ETIMEDOUT:
 966                 dprintk("RPC: %5u rpcbind request timed out\n",
 967                                 task->tk_pid);
 968                 goto retry_timeout;
 969         case -EPFNOSUPPORT:
 970                 /* server doesn't support any rpcbind version we know of */
 971                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 972                                 task->tk_pid);
 973                 break;
 974         case -EPROTONOSUPPORT:
 975                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
 976                                 task->tk_pid);
 977                 task->tk_status = 0;
 978                 task->tk_action = call_bind;
 979                 return;
 980         default:
 981                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 982                                 task->tk_pid, -task->tk_status);
 983         }
 984
 985         rpc_exit(task, status);
 986         return;
 987
 988 retry_timeout:
 989         task->tk_action = call_timeout;
 990 }
 991
 992 /*
 993  * 4b.  Connect to the RPC server
 994  */
 995 static void
 996 call_connect(struct rpc_task *task)
 997 {
 998         struct rpc_xprt *xprt = task->tk_xprt;
 999
1000         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1001                         task->tk_pid, xprt,
1002                         (xprt_connected(xprt) ? "is" : "is not"));
1003
1004         task->tk_action = call_transmit;
1005         if (!xprt_connected(xprt)) {
1006                 task->tk_action = call_connect_status;
1007                 if (task->tk_status < 0)
1008                         return;
1009                 xprt_connect(task);
1010         }
1011 }
1012
1013 /*
1014  * 4c.  Sort out connect result
1015  */
1016 static void
1017 call_connect_status(struct rpc_task *task)
1018 {
1019         struct rpc_clnt *clnt = task->tk_client;
1020         int status = task->tk_status;
1021
1022         dprint_status(task);
1023
1024         task->tk_status = 0;
1025         if (status >= 0) {
1026                 clnt->cl_stats->netreconn++;
1027                 task->tk_action = call_transmit;
1028                 return;
1029         }
1030
1031         /* Something failed: remote service port may have changed */
1032         rpc_force_rebind(clnt);
1033
1034         switch (status) {
1035         case -ENOTCONN:
1036         case -EAGAIN:
1037                 task->tk_action = call_bind;
1038                 if (!RPC_IS_SOFT(task))
1039                         return;
1040                 /* if soft mounted, test if we've timed out */
1041         case -ETIMEDOUT:
1042                 task->tk_action = call_timeout;
1043                 return;
1044         }
1045         rpc_exit(task, -EIO);
1046 }
1047
1048 /*
1049  * 5.   Transmit the RPC request, and wait for reply
1050  */
1051 static void
1052 call_transmit(struct rpc_task *task)
1053 {
1054         dprint_status(task);
1055
1056         task->tk_action = call_status;
1057         if (task->tk_status < 0)
1058                 return;
1059         task->tk_status = xprt_prepare_transmit(task);
1060         if (task->tk_status != 0)
1061                 return;
1062         task->tk_action = call_transmit_status;
1063         /* Encode here so that rpcsec_gss can use correct sequence number. */
1064         if (rpc_task_need_encode(task)) {
1065                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1066                 call_encode(task);
1067                 /* Did the encode result in an error condition? */
1068                 if (task->tk_status != 0)
1069                         return;
1070         }
1071         xprt_transmit(task);
1072         if (task->tk_status < 0)
1073                 return;
1074         /*
1075          * On success, ensure that we call xprt_end_transmit() before sleeping
1076          * in order to allow access to the socket to other RPC requests.
1077          */
1078         call_transmit_status(task);
1079         if (task->tk_msg.rpc_proc->p_decode != NULL)
1080                 return;
1081         task->tk_action = rpc_exit_task;
1082         rpc_wake_up_task(task);
1083 }
1084
1085 /*
1086  * 5a.  Handle cleanup after a transmission
1087  */
1088 static void
1089 call_transmit_status(struct rpc_task *task)
1090 {
1091         task->tk_action = call_status;
1092         /*
1093          * Special case: if we've been waiting on the socket's write_space()
1094          * callback, then don't call xprt_end_transmit().
1095          */
1096         if (task->tk_status == -EAGAIN)
1097                 return;
1098         xprt_end_transmit(task);
1099         rpc_task_force_reencode(task);
1100 }
1101
1102 /*
1103  * 6.   Sort out the RPC call status
1104  */
1105 static void
1106 call_status(struct rpc_task *task)
1107 {
1108         struct rpc_clnt *clnt = task->tk_client;
1109         struct rpc_rqst *req = task->tk_rqstp;
1110         int             status;
1111
1112         if (req->rq_received > 0 && !req->rq_bytes_sent)
1113                 task->tk_status = req->rq_received;
1114
1115         dprint_status(task);
1116
1117         status = task->tk_status;
1118         if (status >= 0) {
1119                 task->tk_action = call_decode;
1120                 return;
1121         }
1122
1123         task->tk_status = 0;
1124         switch(status) {
1125         case -EHOSTDOWN:
1126         case -EHOSTUNREACH:
1127         case -ENETUNREACH:
1128                 /*
1129                  * Delay any retries for 3 seconds, then handle as if it
1130                  * were a timeout.
1131                  */
1132                 rpc_delay(task, 3*HZ);
1133         case -ETIMEDOUT:
1134                 task->tk_action = call_timeout;
1135                 if (task->tk_client->cl_discrtry)
1136                         xprt_force_disconnect(task->tk_xprt);
1137                 break;
1138         case -ECONNREFUSED:
1139         case -ENOTCONN:
1140                 rpc_force_rebind(clnt);
1141                 task->tk_action = call_bind;
1142                 break;
1143         case -EAGAIN:
1144                 task->tk_action = call_transmit;
1145                 break;
1146         case -EIO:
1147                 /* shutdown or soft timeout */
1148                 rpc_exit(task, status);
1149                 break;
1150         default:
1151                 printk("%s: RPC call returned error %d\n",
1152                                clnt->cl_protname, -status);
1153                 rpc_exit(task, status);
1154         }
1155 }
1156
1157 /*
1158  * 6a.  Handle RPC timeout
1159  *      We do not release the request slot, so we keep using the
1160  *      same XID for all retransmits.
1161  */
1162 static void
1163 call_timeout(struct rpc_task *task)
1164 {
1165         struct rpc_clnt *clnt = task->tk_client;
1166
1167         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1168                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1169                 goto retry;
1170         }
1171
1172         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1173         task->tk_timeouts++;
1174
1175         if (RPC_IS_SOFT(task)) {
1176                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1177                                 clnt->cl_protname, clnt->cl_server);
1178                 rpc_exit(task, -EIO);
1179                 return;
1180         }
1181
1182         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1183                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1184                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1185                         clnt->cl_protname, clnt->cl_server);
1186         }
1187         rpc_force_rebind(clnt);
1188
1189 retry:
1190         clnt->cl_stats->rpcretrans++;
1191         task->tk_action = call_bind;
1192         task->tk_status = 0;
1193 }
1194
1195 /*
1196  * 7.   Decode the RPC reply
1197  */
1198 static void
1199 call_decode(struct rpc_task *task)
1200 {
1201         struct rpc_clnt *clnt = task->tk_client;
1202         struct rpc_rqst *req = task->tk_rqstp;
1203         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1204         __be32          *p;
1205
1206         dprintk("RPC: %5u call_decode (status %d)\n",
1207                         task->tk_pid, task->tk_status);
1208
1209         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1210                 printk(KERN_NOTICE "%s: server %s OK\n",
1211                         clnt->cl_protname, clnt->cl_server);
1212                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1213         }
1214
1215         if (task->tk_status < 12) {
1216                 if (!RPC_IS_SOFT(task)) {
1217                         task->tk_action = call_bind;
1218                         clnt->cl_stats->rpcretrans++;
1219                         goto out_retry;
1220                 }
1221                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1222                                 clnt->cl_protname, task->tk_status);
1223                 task->tk_action = call_timeout;
1224                 goto out_retry;
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         /* Verify the RPC header */
1239         p = call_verify(task);
1240         if (IS_ERR(p)) {
1241                 if (p == ERR_PTR(-EAGAIN))
1242                         goto out_retry;
1243                 return;
1244         }
1245
1246         task->tk_action = rpc_exit_task;
1247
1248         if (decode) {
1249                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1250                                                       task->tk_msg.rpc_resp);
1251         }
1252         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1253                         task->tk_status);
1254         return;
1255 out_retry:
1256         req->rq_received = req->rq_private_buf.len = 0;
1257         task->tk_status = 0;
1258         if (task->tk_client->cl_discrtry)
1259                 xprt_force_disconnect(task->tk_xprt);
1260 }
1261
1262 /*
1263  * 8.   Refresh the credentials if rejected by the server
1264  */
1265 static void
1266 call_refresh(struct rpc_task *task)
1267 {
1268         dprint_status(task);
1269
1270         task->tk_action = call_refreshresult;
1271         task->tk_status = 0;
1272         task->tk_client->cl_stats->rpcauthrefresh++;
1273         rpcauth_refreshcred(task);
1274 }
1275
1276 /*
1277  * 8a.  Process the results of a credential refresh
1278  */
1279 static void
1280 call_refreshresult(struct rpc_task *task)
1281 {
1282         int status = task->tk_status;
1283
1284         dprint_status(task);
1285
1286         task->tk_status = 0;
1287         task->tk_action = call_reserve;
1288         if (status >= 0 && rpcauth_uptodatecred(task))
1289                 return;
1290         if (status == -EACCES) {
1291                 rpc_exit(task, -EACCES);
1292                 return;
1293         }
1294         task->tk_action = call_refresh;
1295         if (status != -ETIMEDOUT)
1296                 rpc_delay(task, 3*HZ);
1297         return;
1298 }
1299
1300 /*
1301  * Call header serialization
1302  */
1303 static __be32 *
1304 call_header(struct rpc_task *task)
1305 {
1306         struct rpc_clnt *clnt = task->tk_client;
1307         struct rpc_rqst *req = task->tk_rqstp;
1308         __be32          *p = req->rq_svec[0].iov_base;
1309
1310         /* FIXME: check buffer size? */
1311
1312         p = xprt_skip_transport_header(task->tk_xprt, p);
1313         *p++ = req->rq_xid;             /* XID */
1314         *p++ = htonl(RPC_CALL);         /* CALL */
1315         *p++ = htonl(RPC_VERSION);      /* RPC version */
1316         *p++ = htonl(clnt->cl_prog);    /* program number */
1317         *p++ = htonl(clnt->cl_vers);    /* program version */
1318         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1319         p = rpcauth_marshcred(task, p);
1320         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1321         return p;
1322 }
1323
1324 /*
1325  * Reply header verification
1326  */
1327 static __be32 *
1328 call_verify(struct rpc_task *task)
1329 {
1330         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1331         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1332         __be32  *p = iov->iov_base;
1333         u32 n;
1334         int error = -EACCES;
1335
1336         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1337                 /* RFC-1014 says that the representation of XDR data must be a
1338                  * multiple of four bytes
1339                  * - if it isn't pointer subtraction in the NFS client may give
1340                  *   undefined results
1341                  */
1342                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1343                        " 4 bytes: 0x%x\n", task->tk_pid, __FUNCTION__,
1344                        task->tk_rqstp->rq_rcv_buf.len);
1345                 goto out_eio;
1346         }
1347         if ((len -= 3) < 0)
1348                 goto out_overflow;
1349         p += 1; /* skip XID */
1350
1351         if ((n = ntohl(*p++)) != RPC_REPLY) {
1352                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1353                                 task->tk_pid, __FUNCTION__, n);
1354                 goto out_garbage;
1355         }
1356         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1357                 if (--len < 0)
1358                         goto out_overflow;
1359                 switch ((n = ntohl(*p++))) {
1360                         case RPC_AUTH_ERROR:
1361                                 break;
1362                         case RPC_MISMATCH:
1363                                 dprintk("RPC: %5u %s: RPC call version "
1364                                                 "mismatch!\n",
1365                                                 task->tk_pid, __FUNCTION__);
1366                                 error = -EPROTONOSUPPORT;
1367                                 goto out_err;
1368                         default:
1369                                 dprintk("RPC: %5u %s: RPC call rejected, "
1370                                                 "unknown error: %x\n",
1371                                                 task->tk_pid, __FUNCTION__, n);
1372                                 goto out_eio;
1373                 }
1374                 if (--len < 0)
1375                         goto out_overflow;
1376                 switch ((n = ntohl(*p++))) {
1377                 case RPC_AUTH_REJECTEDCRED:
1378                 case RPC_AUTH_REJECTEDVERF:
1379                 case RPCSEC_GSS_CREDPROBLEM:
1380                 case RPCSEC_GSS_CTXPROBLEM:
1381                         if (!task->tk_cred_retry)
1382                                 break;
1383                         task->tk_cred_retry--;
1384                         dprintk("RPC: %5u %s: retry stale creds\n",
1385                                         task->tk_pid, __FUNCTION__);
1386                         rpcauth_invalcred(task);
1387                         /* Ensure we obtain a new XID! */
1388                         xprt_release(task);
1389                         task->tk_action = call_refresh;
1390                         goto out_retry;
1391                 case RPC_AUTH_BADCRED:
1392                 case RPC_AUTH_BADVERF:
1393                         /* possibly garbled cred/verf? */
1394                         if (!task->tk_garb_retry)
1395                                 break;
1396                         task->tk_garb_retry--;
1397                         dprintk("RPC: %5u %s: retry garbled creds\n",
1398                                         task->tk_pid, __FUNCTION__);
1399                         task->tk_action = call_bind;
1400                         goto out_retry;
1401                 case RPC_AUTH_TOOWEAK:
1402                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1403                                "authentication.\n", task->tk_client->cl_server);
1404                         break;
1405                 default:
1406                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1407                                         task->tk_pid, __FUNCTION__, n);
1408                         error = -EIO;
1409                 }
1410                 dprintk("RPC: %5u %s: call rejected %d\n",
1411                                 task->tk_pid, __FUNCTION__, n);
1412                 goto out_err;
1413         }
1414         if (!(p = rpcauth_checkverf(task, p))) {
1415                 dprintk("RPC: %5u %s: auth check failed\n",
1416                                 task->tk_pid, __FUNCTION__);
1417                 goto out_garbage;               /* bad verifier, retry */
1418         }
1419         len = p - (__be32 *)iov->iov_base - 1;
1420         if (len < 0)
1421                 goto out_overflow;
1422         switch ((n = ntohl(*p++))) {
1423         case RPC_SUCCESS:
1424                 return p;
1425         case RPC_PROG_UNAVAIL:
1426                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1427                                 task->tk_pid, __FUNCTION__,
1428                                 (unsigned int)task->tk_client->cl_prog,
1429                                 task->tk_client->cl_server);
1430                 error = -EPFNOSUPPORT;
1431                 goto out_err;
1432         case RPC_PROG_MISMATCH:
1433                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1434                                 "server %s\n", task->tk_pid, __FUNCTION__,
1435                                 (unsigned int)task->tk_client->cl_prog,
1436                                 (unsigned int)task->tk_client->cl_vers,
1437                                 task->tk_client->cl_server);
1438                 error = -EPROTONOSUPPORT;
1439                 goto out_err;
1440         case RPC_PROC_UNAVAIL:
1441                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1442                                 "version %u on server %s\n",
1443                                 task->tk_pid, __FUNCTION__,
1444                                 task->tk_msg.rpc_proc,
1445                                 task->tk_client->cl_prog,
1446                                 task->tk_client->cl_vers,
1447                                 task->tk_client->cl_server);
1448                 error = -EOPNOTSUPP;
1449                 goto out_err;
1450         case RPC_GARBAGE_ARGS:
1451                 dprintk("RPC: %5u %s: server saw garbage\n",
1452                                 task->tk_pid, __FUNCTION__);
1453                 break;                  /* retry */
1454         default:
1455                 dprintk("RPC: %5u %s: server accept status: %x\n",
1456                                 task->tk_pid, __FUNCTION__, n);
1457                 /* Also retry */
1458         }
1459
1460 out_garbage:
1461         task->tk_client->cl_stats->rpcgarbage++;
1462         if (task->tk_garb_retry) {
1463                 task->tk_garb_retry--;
1464                 dprintk("RPC: %5u %s: retrying\n",
1465                                 task->tk_pid, __FUNCTION__);
1466                 task->tk_action = call_bind;
1467 out_retry:
1468                 return ERR_PTR(-EAGAIN);
1469         }
1470 out_eio:
1471         error = -EIO;
1472 out_err:
1473         rpc_exit(task, error);
1474         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1475                         __FUNCTION__, error);
1476         return ERR_PTR(error);
1477 out_overflow:
1478         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1479                         __FUNCTION__);
1480         goto out_garbage;
1481 }
1482
1483 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1484 {
1485         return 0;
1486 }
1487
1488 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1489 {
1490         return 0;
1491 }
1492
1493 static struct rpc_procinfo rpcproc_null = {
1494         .p_encode = rpcproc_encode_null,
1495         .p_decode = rpcproc_decode_null,
1496 };
1497
1498 static int rpc_ping(struct rpc_clnt *clnt, int flags)
1499 {
1500         struct rpc_message msg = {
1501                 .rpc_proc = &rpcproc_null,
1502         };
1503         int err;
1504         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1505         err = rpc_call_sync(clnt, &msg, flags);
1506         put_rpccred(msg.rpc_cred);
1507         return err;
1508 }
1509
1510 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1511 {
1512         struct rpc_message msg = {
1513                 .rpc_proc = &rpcproc_null,
1514                 .rpc_cred = cred,
1515         };
1516         struct rpc_task_setup task_setup_data = {
1517                 .rpc_client = clnt,
1518                 .rpc_message = &msg,
1519                 .callback_ops = &rpc_default_ops,
1520                 .flags = flags,
1521         };
1522         return rpc_run_task(&task_setup_data);
1523 }
1524 EXPORT_SYMBOL_GPL(rpc_call_null);
1525
1526 #ifdef RPC_DEBUG
1527 void rpc_show_tasks(void)
1528 {
1529         struct rpc_clnt *clnt;
1530         struct rpc_task *t;
1531
1532         spin_lock(&rpc_client_lock);
1533         if (list_empty(&all_clients))
1534                 goto out;
1535         printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
1536                 "-rpcwait -action- ---ops--\n");
1537         list_for_each_entry(clnt, &all_clients, cl_clients) {
1538                 if (list_empty(&clnt->cl_tasks))
1539                         continue;
1540                 spin_lock(&clnt->cl_lock);
1541                 list_for_each_entry(t, &clnt->cl_tasks, tk_task) {
1542                         const char *rpc_waitq = "none";
1543                         int proc;
1544
1545                         if (t->tk_msg.rpc_proc)
1546                                 proc = t->tk_msg.rpc_proc->p_proc;
1547                         else
1548                                 proc = -1;
1549
1550                         if (RPC_IS_QUEUED(t))
1551                                 rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
1552
1553                         printk("%5u %04d %04x %6d %8p %6d %8p %8ld %8s %8p %8p\n",
1554                                 t->tk_pid, proc,
1555                                 t->tk_flags, t->tk_status,
1556                                 t->tk_client,
1557                                 (t->tk_client ? t->tk_client->cl_prog : 0),
1558                                 t->tk_rqstp, t->tk_timeout,
1559                                 rpc_waitq,
1560                                 t->tk_action, t->tk_ops);
1561                 }
1562                 spin_unlock(&clnt->cl_lock);
1563         }
1564 out:
1565         spin_unlock(&rpc_client_lock);
1566 }
1567 #endif