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