net/sunrpc/clnt.c

   1 /*
   2  *  linux/net/sunrpc/clnt.c
   3  *
   4  *  This file contains the high-level RPC interface.
   5  *  It is modeled as a finite state machine to support both synchronous
   6  *  and asynchronous requests.
   7  *
   8  *  -   RPC header generation and argument serialization.
   9  *  -   Credential refresh.
  10  *  -   TCP connect handling.
  11  *  -   Retry of operation when it is suspected the operation failed because
  12  *      of uid squashing on the server, or when the credentials were stale
  13  *      and need to be refreshed, or when a packet was damaged in transit.
  14  *      This may be have to be moved to the VFS layer.
  15  *
  16  *  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/utsname.h>
  31 #include <linux/workqueue.h>
  32
  33 #include <linux/sunrpc/clnt.h>
  34 #include <linux/sunrpc/rpc_pipe_fs.h>
  35 #include <linux/sunrpc/metrics.h>
  36
  37
  38 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
  39
  40 #ifdef RPC_DEBUG
  41 # define RPCDBG_FACILITY        RPCDBG_CALL
  42 #endif
  43
  44 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  45
  46
  47 static void     call_start(struct rpc_task *task);
  48 static void     call_reserve(struct rpc_task *task);
  49 static void     call_reserveresult(struct rpc_task *task);
  50 static void     call_allocate(struct rpc_task *task);
  51 static void     call_encode(struct rpc_task *task);
  52 static void     call_decode(struct rpc_task *task);
  53 static void     call_bind(struct rpc_task *task);
  54 static void     call_bind_status(struct rpc_task *task);
  55 static void     call_transmit(struct rpc_task *task);
  56 static void     call_status(struct rpc_task *task);
  57 static void     call_transmit_status(struct rpc_task *task);
  58 static void     call_refresh(struct rpc_task *task);
  59 static void     call_refreshresult(struct rpc_task *task);
  60 static void     call_timeout(struct rpc_task *task);
  61 static void     call_connect(struct rpc_task *task);
  62 static void     call_connect_status(struct rpc_task *task);
  63 static u32 *    call_header(struct rpc_task *task);
  64 static u32 *    call_verify(struct rpc_task *task);
  65
  66
  67 static int
  68 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  69 {
  70         static uint32_t clntid;
  71         int error;
  72
  73         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  74         clnt->cl_dentry = ERR_PTR(-ENOENT);
  75         if (dir_name == NULL)
  76                 return 0;
  77
  78         clnt->cl_vfsmnt = rpc_get_mount();
  79         if (IS_ERR(clnt->cl_vfsmnt))
  80                 return PTR_ERR(clnt->cl_vfsmnt);
  81
  82         for (;;) {
  83                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  84                                 "%s/clnt%x", dir_name,
  85                                 (unsigned int)clntid++);
  86                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  87                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  88                 if (!IS_ERR(clnt->cl_dentry))
  89                         return 0;
  90                 error = PTR_ERR(clnt->cl_dentry);
  91                 if (error != -EEXIST) {
  92                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  93                                         clnt->cl_pathname, error);
  94                         rpc_put_mount();
  95                         return error;
  96                 }
  97         }
  98 }
  99
 100 /*
 101  * Create an RPC client
 102  * FIXME: This should also take a flags argument (as in task->tk_flags).
 103  * It's called (among others) from pmap_create_client, which may in
 104  * turn be called by an async task. In this case, rpciod should not be
 105  * made to sleep too long.
 106  */
 107 struct rpc_clnt *
 108 rpc_new_client(struct rpc_xprt *xprt, char *servname,
 109                   struct rpc_program *program, u32 vers,
 110                   rpc_authflavor_t flavor)
 111 {
 112         struct rpc_version      *version;
 113         struct rpc_clnt         *clnt = NULL;
 114         struct rpc_auth         *auth;
 115         int err;
 116         int len;
 117
 118         dprintk("RPC: creating %s client for %s (xprt %p)\n",
 119                 program->name, servname, xprt);
 120
 121         err = -EINVAL;
 122         if (!xprt)
 123                 goto out_no_xprt;
 124         if (vers >= program->nrvers || !(version = program->version[vers]))
 125                 goto out_err;
 126
 127         err = -ENOMEM;
 128         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 129         if (!clnt)
 130                 goto out_err;
 131         atomic_set(&clnt->cl_users, 0);
 132         atomic_set(&clnt->cl_count, 1);
 133         clnt->cl_parent = clnt;
 134
 135         clnt->cl_server = clnt->cl_inline_name;
 136         len = strlen(servname) + 1;
 137         if (len > sizeof(clnt->cl_inline_name)) {
 138                 char *buf = kmalloc(len, GFP_KERNEL);
 139                 if (buf != 0)
 140                         clnt->cl_server = buf;
 141                 else
 142                         len = sizeof(clnt->cl_inline_name);
 143         }
 144         strlcpy(clnt->cl_server, servname, len);
 145
 146         clnt->cl_xprt     = xprt;
 147         clnt->cl_procinfo = version->procs;
 148         clnt->cl_maxproc  = version->nrprocs;
 149         clnt->cl_protname = program->name;
 150         clnt->cl_prog     = program->number;
 151         clnt->cl_vers     = version->number;
 152         clnt->cl_stats    = program->stats;
 153         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 154
 155         if (!xprt_bound(clnt->cl_xprt))
 156                 clnt->cl_autobind = 1;
 157
 158         clnt->cl_rtt = &clnt->cl_rtt_default;
 159         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 160
 161         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 162         if (err < 0)
 163                 goto out_no_path;
 164
 165         auth = rpcauth_create(flavor, clnt);
 166         if (IS_ERR(auth)) {
 167                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 168                                 flavor);
 169                 err = PTR_ERR(auth);
 170                 goto out_no_auth;
 171         }
 172
 173         /* save the nodename */
 174         clnt->cl_nodelen = strlen(system_utsname.nodename);
 175         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 176                 clnt->cl_nodelen = UNX_MAXNODENAME;
 177         memcpy(clnt->cl_nodename, system_utsname.nodename, clnt->cl_nodelen);
 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         if (clnt->cl_server != clnt->cl_inline_name)
 187                 kfree(clnt->cl_server);
 188         kfree(clnt);
 189 out_err:
 190         xprt_destroy(xprt);
 191 out_no_xprt:
 192         return ERR_PTR(err);
 193 }
 194
 195 /*
 196  * rpc_create - create an RPC client and transport with one call
 197  * @args: rpc_clnt create argument structure
 198  *
 199  * Creates and initializes an RPC transport and an RPC client.
 200  *
 201  * It can ping the server in order to determine if it is up, and to see if
 202  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 203  * this behavior so asynchronous tasks can also use rpc_create.
 204  */
 205 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 206 {
 207         struct rpc_xprt *xprt;
 208         struct rpc_clnt *clnt;
 209
 210         xprt = xprt_create_transport(args->protocol, args->address,
 211                                         args->addrsize, args->timeout);
 212         if (IS_ERR(xprt))
 213                 return (struct rpc_clnt *)xprt;
 214
 215         /*
 216          * By default, kernel RPC client connects from a reserved port.
 217          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 218          * but it is always enabled for rpciod, which handles the connect
 219          * operation.
 220          */
 221         xprt->resvport = 1;
 222         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 223                 xprt->resvport = 0;
 224
 225         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 226                 args->program->name, args->servername, xprt);
 227
 228         clnt = rpc_new_client(xprt, args->servername, args->program,
 229                                 args->version, args->authflavor);
 230         if (IS_ERR(clnt))
 231                 return clnt;
 232
 233         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 234                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 235                 if (err != 0) {
 236                         rpc_shutdown_client(clnt);
 237                         return ERR_PTR(err);
 238                 }
 239         }
 240
 241         clnt->cl_softrtry = 1;
 242         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 243                 clnt->cl_softrtry = 0;
 244
 245         if (args->flags & RPC_CLNT_CREATE_INTR)
 246                 clnt->cl_intr = 1;
 247         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 248                 clnt->cl_autobind = 1;
 249         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
 250                 clnt->cl_oneshot = 1;
 251
 252         return clnt;
 253 }
 254 EXPORT_SYMBOL(rpc_create);
 255
 256 /**
 257  * Create an RPC client
 258  * @xprt - pointer to xprt struct
 259  * @servname - name of server
 260  * @info - rpc_program
 261  * @version - rpc_program version
 262  * @authflavor - rpc_auth flavour to use
 263  *
 264  * Creates an RPC client structure, then pings the server in order to
 265  * determine if it is up, and if it supports this program and version.
 266  *
 267  * This function should never be called by asynchronous tasks such as
 268  * the portmapper.
 269  */
 270 struct rpc_clnt *rpc_create_client(struct rpc_xprt *xprt, char *servname,
 271                 struct rpc_program *info, u32 version, rpc_authflavor_t authflavor)
 272 {
 273         struct rpc_clnt *clnt;
 274         int err;
 275
 276         clnt = rpc_new_client(xprt, servname, info, version, authflavor);
 277         if (IS_ERR(clnt))
 278                 return clnt;
 279         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 280         if (err == 0)
 281                 return clnt;
 282         rpc_shutdown_client(clnt);
 283         return ERR_PTR(err);
 284 }
 285
 286 /*
 287  * This function clones the RPC client structure. It allows us to share the
 288  * same transport while varying parameters such as the authentication
 289  * flavour.
 290  */
 291 struct rpc_clnt *
 292 rpc_clone_client(struct rpc_clnt *clnt)
 293 {
 294         struct rpc_clnt *new;
 295
 296         new = kmalloc(sizeof(*new), GFP_KERNEL);
 297         if (!new)
 298                 goto out_no_clnt;
 299         memcpy(new, clnt, sizeof(*new));
 300         atomic_set(&new->cl_count, 1);
 301         atomic_set(&new->cl_users, 0);
 302         new->cl_parent = clnt;
 303         atomic_inc(&clnt->cl_count);
 304         /* Turn off autobind on clones */
 305         new->cl_autobind = 0;
 306         new->cl_oneshot = 0;
 307         new->cl_dead = 0;
 308         if (!IS_ERR(new->cl_dentry))
 309                 dget(new->cl_dentry);
 310         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 311         if (new->cl_auth)
 312                 atomic_inc(&new->cl_auth->au_count);
 313         new->cl_metrics = rpc_alloc_iostats(clnt);
 314         return new;
 315 out_no_clnt:
 316         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
 317         return ERR_PTR(-ENOMEM);
 318 }
 319
 320 /*
 321  * Properly shut down an RPC client, terminating all outstanding
 322  * requests. Note that we must be certain that cl_oneshot and
 323  * cl_dead are cleared, or else the client would be destroyed
 324  * when the last task releases it.
 325  */
 326 int
 327 rpc_shutdown_client(struct rpc_clnt *clnt)
 328 {
 329         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 330                         clnt->cl_protname, clnt->cl_server,
 331                         atomic_read(&clnt->cl_users));
 332
 333         while (atomic_read(&clnt->cl_users) > 0) {
 334                 /* Don't let rpc_release_client destroy us */
 335                 clnt->cl_oneshot = 0;
 336                 clnt->cl_dead = 0;
 337                 rpc_killall_tasks(clnt);
 338                 wait_event_timeout(destroy_wait,
 339                         !atomic_read(&clnt->cl_users), 1*HZ);
 340         }
 341
 342         if (atomic_read(&clnt->cl_users) < 0) {
 343                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 344                                 clnt, atomic_read(&clnt->cl_users));
 345 #ifdef RPC_DEBUG
 346                 rpc_show_tasks();
 347 #endif
 348                 BUG();
 349         }
 350
 351         return rpc_destroy_client(clnt);
 352 }
 353
 354 /*
 355  * Delete an RPC client
 356  */
 357 int
 358 rpc_destroy_client(struct rpc_clnt *clnt)
 359 {
 360         if (!atomic_dec_and_test(&clnt->cl_count))
 361                 return 1;
 362         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 363
 364         dprintk("RPC: destroying %s client for %s\n",
 365                         clnt->cl_protname, clnt->cl_server);
 366         if (clnt->cl_auth) {
 367                 rpcauth_destroy(clnt->cl_auth);
 368                 clnt->cl_auth = NULL;
 369         }
 370         if (clnt->cl_parent != clnt) {
 371                 if (!IS_ERR(clnt->cl_dentry))
 372                         dput(clnt->cl_dentry);
 373                 rpc_destroy_client(clnt->cl_parent);
 374                 goto out_free;
 375         }
 376         if (!IS_ERR(clnt->cl_dentry)) {
 377                 rpc_rmdir(clnt->cl_dentry);
 378                 rpc_put_mount();
 379         }
 380         if (clnt->cl_xprt) {
 381                 xprt_destroy(clnt->cl_xprt);
 382                 clnt->cl_xprt = NULL;
 383         }
 384         if (clnt->cl_server != clnt->cl_inline_name)
 385                 kfree(clnt->cl_server);
 386 out_free:
 387         rpc_free_iostats(clnt->cl_metrics);
 388         clnt->cl_metrics = NULL;
 389         kfree(clnt);
 390         return 0;
 391 }
 392
 393 /*
 394  * Release an RPC client
 395  */
 396 void
 397 rpc_release_client(struct rpc_clnt *clnt)
 398 {
 399         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 400                                 clnt, atomic_read(&clnt->cl_users));
 401
 402         if (!atomic_dec_and_test(&clnt->cl_users))
 403                 return;
 404         wake_up(&destroy_wait);
 405         if (clnt->cl_oneshot || clnt->cl_dead)
 406                 rpc_destroy_client(clnt);
 407 }
 408
 409 /**
 410  * rpc_bind_new_program - bind a new RPC program to an existing client
 411  * @old - old rpc_client
 412  * @program - rpc program to set
 413  * @vers - rpc program version
 414  *
 415  * Clones the rpc client and sets up a new RPC program. This is mainly
 416  * of use for enabling different RPC programs to share the same transport.
 417  * The Sun NFSv2/v3 ACL protocol can do this.
 418  */
 419 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 420                                       struct rpc_program *program,
 421                                       int vers)
 422 {
 423         struct rpc_clnt *clnt;
 424         struct rpc_version *version;
 425         int err;
 426
 427         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 428         version = program->version[vers];
 429         clnt = rpc_clone_client(old);
 430         if (IS_ERR(clnt))
 431                 goto out;
 432         clnt->cl_procinfo = version->procs;
 433         clnt->cl_maxproc  = version->nrprocs;
 434         clnt->cl_protname = program->name;
 435         clnt->cl_prog     = program->number;
 436         clnt->cl_vers     = version->number;
 437         clnt->cl_stats    = program->stats;
 438         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 439         if (err != 0) {
 440                 rpc_shutdown_client(clnt);
 441                 clnt = ERR_PTR(err);
 442         }
 443 out:
 444         return clnt;
 445 }
 446
 447 /*
 448  * Default callback for async RPC calls
 449  */
 450 static void
 451 rpc_default_callback(struct rpc_task *task, void *data)
 452 {
 453 }
 454
 455 static const struct rpc_call_ops rpc_default_ops = {
 456         .rpc_call_done = rpc_default_callback,
 457 };
 458
 459 /*
 460  *      Export the signal mask handling for synchronous code that
 461  *      sleeps on RPC calls
 462  */
 463 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 464
 465 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 466 {
 467         unsigned long   sigallow = sigmask(SIGKILL);
 468         sigset_t sigmask;
 469
 470         /* Block all signals except those listed in sigallow */
 471         if (intr)
 472                 sigallow |= RPC_INTR_SIGNALS;
 473         siginitsetinv(&sigmask, sigallow);
 474         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 475 }
 476
 477 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 478 {
 479         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 480 }
 481
 482 static inline void rpc_restore_sigmask(sigset_t *oldset)
 483 {
 484         sigprocmask(SIG_SETMASK, oldset, NULL);
 485 }
 486
 487 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 488 {
 489         rpc_save_sigmask(oldset, clnt->cl_intr);
 490 }
 491
 492 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 493 {
 494         rpc_restore_sigmask(oldset);
 495 }
 496
 497 /*
 498  * New rpc_call implementation
 499  */
 500 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 501 {
 502         struct rpc_task *task;
 503         sigset_t        oldset;
 504         int             status;
 505
 506         /* If this client is slain all further I/O fails */
 507         if (clnt->cl_dead)
 508                 return -EIO;
 509
 510         BUG_ON(flags & RPC_TASK_ASYNC);
 511
 512         status = -ENOMEM;
 513         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 514         if (task == NULL)
 515                 goto out;
 516
 517         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 518         rpc_task_sigmask(task, &oldset);
 519
 520         rpc_call_setup(task, msg, 0);
 521
 522         /* Set up the call info struct and execute the task */
 523         status = task->tk_status;
 524         if (status == 0) {
 525                 atomic_inc(&task->tk_count);
 526                 status = rpc_execute(task);
 527                 if (status == 0)
 528                         status = task->tk_status;
 529         }
 530         rpc_restore_sigmask(&oldset);
 531         rpc_release_task(task);
 532 out:
 533         return status;
 534 }
 535
 536 /*
 537  * New rpc_call implementation
 538  */
 539 int
 540 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 541                const struct rpc_call_ops *tk_ops, void *data)
 542 {
 543         struct rpc_task *task;
 544         sigset_t        oldset;
 545         int             status;
 546
 547         /* If this client is slain all further I/O fails */
 548         status = -EIO;
 549         if (clnt->cl_dead)
 550                 goto out_release;
 551
 552         flags |= RPC_TASK_ASYNC;
 553
 554         /* Create/initialize a new RPC task */
 555         status = -ENOMEM;
 556         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 557                 goto out_release;
 558
 559         /* Mask signals on GSS_AUTH upcalls */
 560         rpc_task_sigmask(task, &oldset);
 561
 562         rpc_call_setup(task, msg, 0);
 563
 564         /* Set up the call info struct and execute the task */
 565         status = task->tk_status;
 566         if (status == 0)
 567                 rpc_execute(task);
 568         else
 569                 rpc_release_task(task);
 570
 571         rpc_restore_sigmask(&oldset);
 572         return status;
 573 out_release:
 574         if (tk_ops->rpc_release != NULL)
 575                 tk_ops->rpc_release(data);
 576         return status;
 577 }
 578
 579
 580 void
 581 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 582 {
 583         task->tk_msg   = *msg;
 584         task->tk_flags |= flags;
 585         /* Bind the user cred */
 586         if (task->tk_msg.rpc_cred != NULL)
 587                 rpcauth_holdcred(task);
 588         else
 589                 rpcauth_bindcred(task);
 590
 591         if (task->tk_status == 0)
 592                 task->tk_action = call_start;
 593         else
 594                 task->tk_action = rpc_exit_task;
 595 }
 596
 597 /**
 598  * rpc_peeraddr - extract remote peer address from clnt's xprt
 599  * @clnt: RPC client structure
 600  * @buf: target buffer
 601  * @size: length of target buffer
 602  *
 603  * Returns the number of bytes that are actually in the stored address.
 604  */
 605 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 606 {
 607         size_t bytes;
 608         struct rpc_xprt *xprt = clnt->cl_xprt;
 609
 610         bytes = sizeof(xprt->addr);
 611         if (bytes > bufsize)
 612                 bytes = bufsize;
 613         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 614         return xprt->addrlen;
 615 }
 616 EXPORT_SYMBOL(rpc_peeraddr);
 617
 618 /**
 619  * rpc_peeraddr2str - return remote peer address in printable format
 620  * @clnt: RPC client structure
 621  * @format: address format
 622  *
 623  */
 624 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 625 {
 626         struct rpc_xprt *xprt = clnt->cl_xprt;
 627         return xprt->ops->print_addr(xprt, format);
 628 }
 629 EXPORT_SYMBOL(rpc_peeraddr2str);
 630
 631 void
 632 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 633 {
 634         struct rpc_xprt *xprt = clnt->cl_xprt;
 635         if (xprt->ops->set_buffer_size)
 636                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 637 }
 638
 639 /*
 640  * Return size of largest payload RPC client can support, in bytes
 641  *
 642  * For stream transports, this is one RPC record fragment (see RFC
 643  * 1831), as we don't support multi-record requests yet.  For datagram
 644  * transports, this is the size of an IP packet minus the IP, UDP, and
 645  * RPC header sizes.
 646  */
 647 size_t rpc_max_payload(struct rpc_clnt *clnt)
 648 {
 649         return clnt->cl_xprt->max_payload;
 650 }
 651 EXPORT_SYMBOL(rpc_max_payload);
 652
 653 /**
 654  * rpc_force_rebind - force transport to check that remote port is unchanged
 655  * @clnt: client to rebind
 656  *
 657  */
 658 void rpc_force_rebind(struct rpc_clnt *clnt)
 659 {
 660         if (clnt->cl_autobind)
 661                 xprt_clear_bound(clnt->cl_xprt);
 662 }
 663 EXPORT_SYMBOL(rpc_force_rebind);
 664
 665 /*
 666  * Restart an (async) RPC call. Usually called from within the
 667  * exit handler.
 668  */
 669 void
 670 rpc_restart_call(struct rpc_task *task)
 671 {
 672         if (RPC_ASSASSINATED(task))
 673                 return;
 674
 675         task->tk_action = call_start;
 676 }
 677
 678 /*
 679  * 0.  Initial state
 680  *
 681  *     Other FSM states can be visited zero or more times, but
 682  *     this state is visited exactly once for each RPC.
 683  */
 684 static void
 685 call_start(struct rpc_task *task)
 686 {
 687         struct rpc_clnt *clnt = task->tk_client;
 688
 689         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 690                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 691                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 692
 693         /* Increment call count */
 694         task->tk_msg.rpc_proc->p_count++;
 695         clnt->cl_stats->rpccnt++;
 696         task->tk_action = call_reserve;
 697 }
 698
 699 /*
 700  * 1.   Reserve an RPC call slot
 701  */
 702 static void
 703 call_reserve(struct rpc_task *task)
 704 {
 705         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 706
 707         if (!rpcauth_uptodatecred(task)) {
 708                 task->tk_action = call_refresh;
 709                 return;
 710         }
 711
 712         task->tk_status  = 0;
 713         task->tk_action  = call_reserveresult;
 714         xprt_reserve(task);
 715 }
 716
 717 /*
 718  * 1b.  Grok the result of xprt_reserve()
 719  */
 720 static void
 721 call_reserveresult(struct rpc_task *task)
 722 {
 723         int status = task->tk_status;
 724
 725         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 726                                 task->tk_pid, task->tk_status);
 727
 728         /*
 729          * After a call to xprt_reserve(), we must have either
 730          * a request slot or else an error status.
 731          */
 732         task->tk_status = 0;
 733         if (status >= 0) {
 734                 if (task->tk_rqstp) {
 735                         task->tk_action = call_allocate;
 736                         return;
 737                 }
 738
 739                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 740                                 __FUNCTION__, status);
 741                 rpc_exit(task, -EIO);
 742                 return;
 743         }
 744
 745         /*
 746          * Even though there was an error, we may have acquired
 747          * a request slot somehow.  Make sure not to leak it.
 748          */
 749         if (task->tk_rqstp) {
 750                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 751                                 __FUNCTION__, status);
 752                 xprt_release(task);
 753         }
 754
 755         switch (status) {
 756         case -EAGAIN:   /* woken up; retry */
 757                 task->tk_action = call_reserve;
 758                 return;
 759         case -EIO:      /* probably a shutdown */
 760                 break;
 761         default:
 762                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 763                                 __FUNCTION__, status);
 764                 break;
 765         }
 766         rpc_exit(task, status);
 767 }
 768
 769 /*
 770  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 771  *      (Note: buffer memory is freed in xprt_release).
 772  */
 773 static void
 774 call_allocate(struct rpc_task *task)
 775 {
 776         struct rpc_rqst *req = task->tk_rqstp;
 777         struct rpc_xprt *xprt = task->tk_xprt;
 778         unsigned int    bufsiz;
 779
 780         dprintk("RPC: %4d call_allocate (status %d)\n",
 781                                 task->tk_pid, task->tk_status);
 782         task->tk_action = call_bind;
 783         if (req->rq_buffer)
 784                 return;
 785
 786         /* FIXME: compute buffer requirements more exactly using
 787          * auth->au_wslack */
 788         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 789
 790         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 791                 return;
 792         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 793
 794         if (RPC_IS_ASYNC(task) || !signalled()) {
 795                 xprt_release(task);
 796                 task->tk_action = call_reserve;
 797                 rpc_delay(task, HZ>>4);
 798                 return;
 799         }
 800
 801         rpc_exit(task, -ERESTARTSYS);
 802 }
 803
 804 static inline int
 805 rpc_task_need_encode(struct rpc_task *task)
 806 {
 807         return task->tk_rqstp->rq_snd_buf.len == 0;
 808 }
 809
 810 static inline void
 811 rpc_task_force_reencode(struct rpc_task *task)
 812 {
 813         task->tk_rqstp->rq_snd_buf.len = 0;
 814 }
 815
 816 /*
 817  * 3.   Encode arguments of an RPC call
 818  */
 819 static void
 820 call_encode(struct rpc_task *task)
 821 {
 822         struct rpc_rqst *req = task->tk_rqstp;
 823         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 824         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 825         unsigned int    bufsiz;
 826         kxdrproc_t      encode;
 827         u32             *p;
 828
 829         dprintk("RPC: %4d call_encode (status %d)\n",
 830                                 task->tk_pid, task->tk_status);
 831
 832         /* Default buffer setup */
 833         bufsiz = req->rq_bufsize >> 1;
 834         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 835         sndbuf->head[0].iov_len  = bufsiz;
 836         sndbuf->tail[0].iov_len  = 0;
 837         sndbuf->page_len         = 0;
 838         sndbuf->len              = 0;
 839         sndbuf->buflen           = bufsiz;
 840         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 841         rcvbuf->head[0].iov_len  = bufsiz;
 842         rcvbuf->tail[0].iov_len  = 0;
 843         rcvbuf->page_len         = 0;
 844         rcvbuf->len              = 0;
 845         rcvbuf->buflen           = bufsiz;
 846
 847         /* Encode header and provided arguments */
 848         encode = task->tk_msg.rpc_proc->p_encode;
 849         if (!(p = call_header(task))) {
 850                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 851                 rpc_exit(task, -EIO);
 852                 return;
 853         }
 854         if (encode == NULL)
 855                 return;
 856
 857         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 858                         task->tk_msg.rpc_argp);
 859         if (task->tk_status == -ENOMEM) {
 860                 /* XXX: Is this sane? */
 861                 rpc_delay(task, 3*HZ);
 862                 task->tk_status = -EAGAIN;
 863         }
 864 }
 865
 866 /*
 867  * 4.   Get the server port number if not yet set
 868  */
 869 static void
 870 call_bind(struct rpc_task *task)
 871 {
 872         struct rpc_xprt *xprt = task->tk_xprt;
 873
 874         dprintk("RPC: %4d call_bind (status %d)\n",
 875                                 task->tk_pid, task->tk_status);
 876
 877         task->tk_action = call_connect;
 878         if (!xprt_bound(xprt)) {
 879                 task->tk_action = call_bind_status;
 880                 task->tk_timeout = xprt->bind_timeout;
 881                 xprt->ops->rpcbind(task);
 882         }
 883 }
 884
 885 /*
 886  * 4a.  Sort out bind result
 887  */
 888 static void
 889 call_bind_status(struct rpc_task *task)
 890 {
 891         int status = -EACCES;
 892
 893         if (task->tk_status >= 0) {
 894                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 895                                         task->tk_pid, task->tk_status);
 896                 task->tk_status = 0;
 897                 task->tk_action = call_connect;
 898                 return;
 899         }
 900
 901         switch (task->tk_status) {
 902         case -EACCES:
 903                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 904                                 task->tk_pid);
 905                 rpc_delay(task, 3*HZ);
 906                 goto retry_bind;
 907         case -ETIMEDOUT:
 908                 dprintk("RPC: %4d rpcbind request timed out\n",
 909                                 task->tk_pid);
 910                 if (RPC_IS_SOFT(task)) {
 911                         status = -EIO;
 912                         break;
 913                 }
 914                 goto retry_bind;
 915         case -EPFNOSUPPORT:
 916                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 917                                 task->tk_pid);
 918                 break;
 919         case -EPROTONOSUPPORT:
 920                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 921                                 task->tk_pid);
 922                 break;
 923         default:
 924                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 925                                 task->tk_pid, -task->tk_status);
 926                 status = -EIO;
 927                 break;
 928         }
 929
 930         rpc_exit(task, status);
 931         return;
 932
 933 retry_bind:
 934         task->tk_status = 0;
 935         task->tk_action = call_bind;
 936         return;
 937 }
 938
 939 /*
 940  * 4b.  Connect to the RPC server
 941  */
 942 static void
 943 call_connect(struct rpc_task *task)
 944 {
 945         struct rpc_xprt *xprt = task->tk_xprt;
 946
 947         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 948                         task->tk_pid, xprt,
 949                         (xprt_connected(xprt) ? "is" : "is not"));
 950
 951         task->tk_action = call_transmit;
 952         if (!xprt_connected(xprt)) {
 953                 task->tk_action = call_connect_status;
 954                 if (task->tk_status < 0)
 955                         return;
 956                 xprt_connect(task);
 957         }
 958 }
 959
 960 /*
 961  * 4c.  Sort out connect result
 962  */
 963 static void
 964 call_connect_status(struct rpc_task *task)
 965 {
 966         struct rpc_clnt *clnt = task->tk_client;
 967         int status = task->tk_status;
 968
 969         dprintk("RPC: %5u call_connect_status (status %d)\n",
 970                                 task->tk_pid, task->tk_status);
 971
 972         task->tk_status = 0;
 973         if (status >= 0) {
 974                 clnt->cl_stats->netreconn++;
 975                 task->tk_action = call_transmit;
 976                 return;
 977         }
 978
 979         /* Something failed: remote service port may have changed */
 980         rpc_force_rebind(clnt);
 981
 982         switch (status) {
 983         case -ENOTCONN:
 984         case -ETIMEDOUT:
 985         case -EAGAIN:
 986                 task->tk_action = call_bind;
 987                 break;
 988         default:
 989                 rpc_exit(task, -EIO);
 990                 break;
 991         }
 992 }
 993
 994 /*
 995  * 5.   Transmit the RPC request, and wait for reply
 996  */
 997 static void
 998 call_transmit(struct rpc_task *task)
 999 {
1000         dprintk("RPC: %4d call_transmit (status %d)\n",
1001                                 task->tk_pid, task->tk_status);
1002
1003         task->tk_action = call_status;
1004         if (task->tk_status < 0)
1005                 return;
1006         task->tk_status = xprt_prepare_transmit(task);
1007         if (task->tk_status != 0)
1008                 return;
1009         task->tk_action = call_transmit_status;
1010         /* Encode here so that rpcsec_gss can use correct sequence number. */
1011         if (rpc_task_need_encode(task)) {
1012                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1013                 call_encode(task);
1014                 /* Did the encode result in an error condition? */
1015                 if (task->tk_status != 0)
1016                         return;
1017         }
1018         xprt_transmit(task);
1019         if (task->tk_status < 0)
1020                 return;
1021         /*
1022          * On success, ensure that we call xprt_end_transmit() before sleeping
1023          * in order to allow access to the socket to other RPC requests.
1024          */
1025         call_transmit_status(task);
1026         if (task->tk_msg.rpc_proc->p_decode != NULL)
1027                 return;
1028         task->tk_action = rpc_exit_task;
1029         rpc_wake_up_task(task);
1030 }
1031
1032 /*
1033  * 5a.  Handle cleanup after a transmission
1034  */
1035 static void
1036 call_transmit_status(struct rpc_task *task)
1037 {
1038         task->tk_action = call_status;
1039         /*
1040          * Special case: if we've been waiting on the socket's write_space()
1041          * callback, then don't call xprt_end_transmit().
1042          */
1043         if (task->tk_status == -EAGAIN)
1044                 return;
1045         xprt_end_transmit(task);
1046         rpc_task_force_reencode(task);
1047 }
1048
1049 /*
1050  * 6.   Sort out the RPC call status
1051  */
1052 static void
1053 call_status(struct rpc_task *task)
1054 {
1055         struct rpc_clnt *clnt = task->tk_client;
1056         struct rpc_rqst *req = task->tk_rqstp;
1057         int             status;
1058
1059         if (req->rq_received > 0 && !req->rq_bytes_sent)
1060                 task->tk_status = req->rq_received;
1061
1062         dprintk("RPC: %4d call_status (status %d)\n",
1063                                 task->tk_pid, task->tk_status);
1064
1065         status = task->tk_status;
1066         if (status >= 0) {
1067                 task->tk_action = call_decode;
1068                 return;
1069         }
1070
1071         task->tk_status = 0;
1072         switch(status) {
1073         case -ETIMEDOUT:
1074                 task->tk_action = call_timeout;
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                 break;
1093         }
1094 }
1095
1096 /*
1097  * 6a.  Handle RPC timeout
1098  *      We do not release the request slot, so we keep using the
1099  *      same XID for all retransmits.
1100  */
1101 static void
1102 call_timeout(struct rpc_task *task)
1103 {
1104         struct rpc_clnt *clnt = task->tk_client;
1105
1106         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1107                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1108                 goto retry;
1109         }
1110
1111         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1112         task->tk_timeouts++;
1113
1114         if (RPC_IS_SOFT(task)) {
1115                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1116                                 clnt->cl_protname, clnt->cl_server);
1117                 rpc_exit(task, -EIO);
1118                 return;
1119         }
1120
1121         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1122                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1123                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1124                         clnt->cl_protname, clnt->cl_server);
1125         }
1126         rpc_force_rebind(clnt);
1127
1128 retry:
1129         clnt->cl_stats->rpcretrans++;
1130         task->tk_action = call_bind;
1131         task->tk_status = 0;
1132 }
1133
1134 /*
1135  * 7.   Decode the RPC reply
1136  */
1137 static void
1138 call_decode(struct rpc_task *task)
1139 {
1140         struct rpc_clnt *clnt = task->tk_client;
1141         struct rpc_rqst *req = task->tk_rqstp;
1142         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1143         u32             *p;
1144
1145         dprintk("RPC: %4d call_decode (status %d)\n",
1146                                 task->tk_pid, task->tk_status);
1147
1148         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1149                 printk(KERN_NOTICE "%s: server %s OK\n",
1150                         clnt->cl_protname, clnt->cl_server);
1151                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1152         }
1153
1154         if (task->tk_status < 12) {
1155                 if (!RPC_IS_SOFT(task)) {
1156                         task->tk_action = call_bind;
1157                         clnt->cl_stats->rpcretrans++;
1158                         goto out_retry;
1159                 }
1160                 printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1161                         clnt->cl_protname, task->tk_status);
1162                 rpc_exit(task, -EIO);
1163                 return;
1164         }
1165
1166         /*
1167          * Ensure that we see all writes made by xprt_complete_rqst()
1168          * before it changed req->rq_received.
1169          */
1170         smp_rmb();
1171         req->rq_rcv_buf.len = req->rq_private_buf.len;
1172
1173         /* Check that the softirq receive buffer is valid */
1174         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1175                                 sizeof(req->rq_rcv_buf)) != 0);
1176
1177         /* Verify the RPC header */
1178         p = call_verify(task);
1179         if (IS_ERR(p)) {
1180                 if (p == ERR_PTR(-EAGAIN))
1181                         goto out_retry;
1182                 return;
1183         }
1184
1185         task->tk_action = rpc_exit_task;
1186
1187         if (decode)
1188                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1189                                                       task->tk_msg.rpc_resp);
1190         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1191                                         task->tk_status);
1192         return;
1193 out_retry:
1194         req->rq_received = req->rq_private_buf.len = 0;
1195         task->tk_status = 0;
1196 }
1197
1198 /*
1199  * 8.   Refresh the credentials if rejected by the server
1200  */
1201 static void
1202 call_refresh(struct rpc_task *task)
1203 {
1204         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1205
1206         xprt_release(task);     /* Must do to obtain new XID */
1207         task->tk_action = call_refreshresult;
1208         task->tk_status = 0;
1209         task->tk_client->cl_stats->rpcauthrefresh++;
1210         rpcauth_refreshcred(task);
1211 }
1212
1213 /*
1214  * 8a.  Process the results of a credential refresh
1215  */
1216 static void
1217 call_refreshresult(struct rpc_task *task)
1218 {
1219         int status = task->tk_status;
1220         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1221                                 task->tk_pid, task->tk_status);
1222
1223         task->tk_status = 0;
1224         task->tk_action = call_reserve;
1225         if (status >= 0 && rpcauth_uptodatecred(task))
1226                 return;
1227         if (status == -EACCES) {
1228                 rpc_exit(task, -EACCES);
1229                 return;
1230         }
1231         task->tk_action = call_refresh;
1232         if (status != -ETIMEDOUT)
1233                 rpc_delay(task, 3*HZ);
1234         return;
1235 }
1236
1237 /*
1238  * Call header serialization
1239  */
1240 static u32 *
1241 call_header(struct rpc_task *task)
1242 {
1243         struct rpc_clnt *clnt = task->tk_client;
1244         struct rpc_rqst *req = task->tk_rqstp;
1245         u32             *p = req->rq_svec[0].iov_base;
1246
1247         /* FIXME: check buffer size? */
1248
1249         p = xprt_skip_transport_header(task->tk_xprt, p);
1250         *p++ = req->rq_xid;             /* XID */
1251         *p++ = htonl(RPC_CALL);         /* CALL */
1252         *p++ = htonl(RPC_VERSION);      /* RPC version */
1253         *p++ = htonl(clnt->cl_prog);    /* program number */
1254         *p++ = htonl(clnt->cl_vers);    /* program version */
1255         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1256         p = rpcauth_marshcred(task, p);
1257         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1258         return p;
1259 }
1260
1261 /*
1262  * Reply header verification
1263  */
1264 static u32 *
1265 call_verify(struct rpc_task *task)
1266 {
1267         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1268         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1269         u32     *p = iov->iov_base, n;
1270         int error = -EACCES;
1271
1272         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1273                 /* RFC-1014 says that the representation of XDR data must be a
1274                  * multiple of four bytes
1275                  * - if it isn't pointer subtraction in the NFS client may give
1276                  *   undefined results
1277                  */
1278                 printk(KERN_WARNING
1279                        "call_verify: XDR representation not a multiple of"
1280                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1281                 goto out_eio;
1282         }
1283         if ((len -= 3) < 0)
1284                 goto out_overflow;
1285         p += 1; /* skip XID */
1286
1287         if ((n = ntohl(*p++)) != RPC_REPLY) {
1288                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1289                 goto out_garbage;
1290         }
1291         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1292                 if (--len < 0)
1293                         goto out_overflow;
1294                 switch ((n = ntohl(*p++))) {
1295                         case RPC_AUTH_ERROR:
1296                                 break;
1297                         case RPC_MISMATCH:
1298                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1299                                 error = -EPROTONOSUPPORT;
1300                                 goto out_err;
1301                         default:
1302                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1303                                 goto out_eio;
1304                 }
1305                 if (--len < 0)
1306                         goto out_overflow;
1307                 switch ((n = ntohl(*p++))) {
1308                 case RPC_AUTH_REJECTEDCRED:
1309                 case RPC_AUTH_REJECTEDVERF:
1310                 case RPCSEC_GSS_CREDPROBLEM:
1311                 case RPCSEC_GSS_CTXPROBLEM:
1312                         if (!task->tk_cred_retry)
1313                                 break;
1314                         task->tk_cred_retry--;
1315                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1316                                                         task->tk_pid);
1317                         rpcauth_invalcred(task);
1318                         task->tk_action = call_refresh;
1319                         goto out_retry;
1320                 case RPC_AUTH_BADCRED:
1321                 case RPC_AUTH_BADVERF:
1322                         /* possibly garbled cred/verf? */
1323                         if (!task->tk_garb_retry)
1324                                 break;
1325                         task->tk_garb_retry--;
1326                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1327                                                         task->tk_pid);
1328                         task->tk_action = call_bind;
1329                         goto out_retry;
1330                 case RPC_AUTH_TOOWEAK:
1331                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1332                                "authentication.\n", task->tk_client->cl_server);
1333                         break;
1334                 default:
1335                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1336                         error = -EIO;
1337                 }
1338                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1339                                                 task->tk_pid, n);
1340                 goto out_err;
1341         }
1342         if (!(p = rpcauth_checkverf(task, p))) {
1343                 printk(KERN_WARNING "call_verify: auth check failed\n");
1344                 goto out_garbage;               /* bad verifier, retry */
1345         }
1346         len = p - (u32 *)iov->iov_base - 1;
1347         if (len < 0)
1348                 goto out_overflow;
1349         switch ((n = ntohl(*p++))) {
1350         case RPC_SUCCESS:
1351                 return p;
1352         case RPC_PROG_UNAVAIL:
1353                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1354                                 (unsigned int)task->tk_client->cl_prog,
1355                                 task->tk_client->cl_server);
1356                 error = -EPFNOSUPPORT;
1357                 goto out_err;
1358         case RPC_PROG_MISMATCH:
1359                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1360                                 (unsigned int)task->tk_client->cl_prog,
1361                                 (unsigned int)task->tk_client->cl_vers,
1362                                 task->tk_client->cl_server);
1363                 error = -EPROTONOSUPPORT;
1364                 goto out_err;
1365         case RPC_PROC_UNAVAIL:
1366                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1367                                 task->tk_msg.rpc_proc,
1368                                 task->tk_client->cl_prog,
1369                                 task->tk_client->cl_vers,
1370                                 task->tk_client->cl_server);
1371                 error = -EOPNOTSUPP;
1372                 goto out_err;
1373         case RPC_GARBAGE_ARGS:
1374                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1375                 break;                  /* retry */
1376         default:
1377                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1378                 /* Also retry */
1379         }
1380
1381 out_garbage:
1382         task->tk_client->cl_stats->rpcgarbage++;
1383         if (task->tk_garb_retry) {
1384                 task->tk_garb_retry--;
1385                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1386                 task->tk_action = call_bind;
1387 out_retry:
1388                 return ERR_PTR(-EAGAIN);
1389         }
1390         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1391 out_eio:
1392         error = -EIO;
1393 out_err:
1394         rpc_exit(task, error);
1395         return ERR_PTR(error);
1396 out_overflow:
1397         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1398         goto out_garbage;
1399 }
1400
1401 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1402 {
1403         return 0;
1404 }
1405
1406 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1407 {
1408         return 0;
1409 }
1410
1411 static struct rpc_procinfo rpcproc_null = {
1412         .p_encode = rpcproc_encode_null,
1413         .p_decode = rpcproc_decode_null,
1414 };
1415
1416 int rpc_ping(struct rpc_clnt *clnt, int flags)
1417 {
1418         struct rpc_message msg = {
1419                 .rpc_proc = &rpcproc_null,
1420         };
1421         int err;
1422         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1423         err = rpc_call_sync(clnt, &msg, flags);
1424         put_rpccred(msg.rpc_cred);
1425         return err;
1426 }