Pileus Git - ~andy/linux/blob - 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
  32 #include <linux/sunrpc/clnt.h>
  33 #include <linux/workqueue.h>
  34 #include <linux/sunrpc/rpc_pipe_fs.h>
  35
  36 #include <linux/nfs.h>
  37
  38
  39 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
  40
  41 #ifdef RPC_DEBUG
  42 # define RPCDBG_FACILITY        RPCDBG_CALL
  43 #endif
  44
  45 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  46
  47
  48 static void     call_start(struct rpc_task *task);
  49 static void     call_reserve(struct rpc_task *task);
  50 static void     call_reserveresult(struct rpc_task *task);
  51 static void     call_allocate(struct rpc_task *task);
  52 static void     call_encode(struct rpc_task *task);
  53 static void     call_decode(struct rpc_task *task);
  54 static void     call_bind(struct rpc_task *task);
  55 static void     call_bind_status(struct rpc_task *task);
  56 static void     call_transmit(struct rpc_task *task);
  57 static void     call_status(struct rpc_task *task);
  58 static void     call_transmit_status(struct rpc_task *task);
  59 static void     call_refresh(struct rpc_task *task);
  60 static void     call_refreshresult(struct rpc_task *task);
  61 static void     call_timeout(struct rpc_task *task);
  62 static void     call_connect(struct rpc_task *task);
  63 static void     call_connect_status(struct rpc_task *task);
  64 static u32 *    call_header(struct rpc_task *task);
  65 static u32 *    call_verify(struct rpc_task *task);
  66
  67
  68 static int
  69 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  70 {
  71         static uint32_t clntid;
  72         int error;
  73
  74         if (dir_name == NULL)
  75                 return 0;
  76         for (;;) {
  77                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  78                                 "%s/clnt%x", dir_name,
  79                                 (unsigned int)clntid++);
  80                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  81                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  82                 if (!IS_ERR(clnt->cl_dentry))
  83                         return 0;
  84                 error = PTR_ERR(clnt->cl_dentry);
  85                 if (error != -EEXIST) {
  86                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  87                                         clnt->cl_pathname, error);
  88                         return error;
  89                 }
  90         }
  91 }
  92
  93 /*
  94  * Create an RPC client
  95  * FIXME: This should also take a flags argument (as in task->tk_flags).
  96  * It's called (among others) from pmap_create_client, which may in
  97  * turn be called by an async task. In this case, rpciod should not be
  98  * made to sleep too long.
  99  */
 100 struct rpc_clnt *
 101 rpc_new_client(struct rpc_xprt *xprt, char *servname,
 102                   struct rpc_program *program, u32 vers,
 103                   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_err;
 117         if (vers >= program->nrvers || !(version = program->version[vers]))
 118                 goto out_err;
 119
 120         err = -ENOMEM;
 121         clnt = (struct rpc_clnt *) kmalloc(sizeof(*clnt), GFP_KERNEL);
 122         if (!clnt)
 123                 goto out_err;
 124         memset(clnt, 0, sizeof(*clnt));
 125         atomic_set(&clnt->cl_users, 0);
 126         atomic_set(&clnt->cl_count, 1);
 127         clnt->cl_parent = clnt;
 128
 129         clnt->cl_server = clnt->cl_inline_name;
 130         len = strlen(servname) + 1;
 131         if (len > sizeof(clnt->cl_inline_name)) {
 132                 char *buf = kmalloc(len, GFP_KERNEL);
 133                 if (buf != 0)
 134                         clnt->cl_server = buf;
 135                 else
 136                         len = sizeof(clnt->cl_inline_name);
 137         }
 138         strlcpy(clnt->cl_server, servname, len);
 139
 140         clnt->cl_xprt     = xprt;
 141         clnt->cl_procinfo = version->procs;
 142         clnt->cl_maxproc  = version->nrprocs;
 143         clnt->cl_protname = program->name;
 144         clnt->cl_pmap     = &clnt->cl_pmap_default;
 145         clnt->cl_port     = xprt->addr.sin_port;
 146         clnt->cl_prog     = program->number;
 147         clnt->cl_vers     = version->number;
 148         clnt->cl_prot     = xprt->prot;
 149         clnt->cl_stats    = program->stats;
 150         rpc_init_wait_queue(&clnt->cl_pmap_default.pm_bindwait, "bindwait");
 151
 152         if (!clnt->cl_port)
 153                 clnt->cl_autobind = 1;
 154
 155         clnt->cl_rtt = &clnt->cl_rtt_default;
 156         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 157
 158         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 159         if (err < 0)
 160                 goto out_no_path;
 161
 162         auth = rpcauth_create(flavor, clnt);
 163         if (IS_ERR(auth)) {
 164                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 165                                 flavor);
 166                 err = PTR_ERR(auth);
 167                 goto out_no_auth;
 168         }
 169
 170         /* save the nodename */
 171         clnt->cl_nodelen = strlen(system_utsname.nodename);
 172         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 173                 clnt->cl_nodelen = UNX_MAXNODENAME;
 174         memcpy(clnt->cl_nodename, system_utsname.nodename, clnt->cl_nodelen);
 175         return clnt;
 176
 177 out_no_auth:
 178         rpc_rmdir(clnt->cl_pathname);
 179 out_no_path:
 180         if (clnt->cl_server != clnt->cl_inline_name)
 181                 kfree(clnt->cl_server);
 182         kfree(clnt);
 183 out_err:
 184         xprt_destroy(xprt);
 185         return ERR_PTR(err);
 186 }
 187
 188 /**
 189  * Create an RPC client
 190  * @xprt - pointer to xprt struct
 191  * @servname - name of server
 192  * @info - rpc_program
 193  * @version - rpc_program version
 194  * @authflavor - rpc_auth flavour to use
 195  *
 196  * Creates an RPC client structure, then pings the server in order to
 197  * determine if it is up, and if it supports this program and version.
 198  *
 199  * This function should never be called by asynchronous tasks such as
 200  * the portmapper.
 201  */
 202 struct rpc_clnt *rpc_create_client(struct rpc_xprt *xprt, char *servname,
 203                 struct rpc_program *info, u32 version, rpc_authflavor_t authflavor)
 204 {
 205         struct rpc_clnt *clnt;
 206         int err;
 207
 208         clnt = rpc_new_client(xprt, servname, info, version, authflavor);
 209         if (IS_ERR(clnt))
 210                 return clnt;
 211         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 212         if (err == 0)
 213                 return clnt;
 214         rpc_shutdown_client(clnt);
 215         return ERR_PTR(err);
 216 }
 217
 218 /*
 219  * This function clones the RPC client structure. It allows us to share the
 220  * same transport while varying parameters such as the authentication
 221  * flavour.
 222  */
 223 struct rpc_clnt *
 224 rpc_clone_client(struct rpc_clnt *clnt)
 225 {
 226         struct rpc_clnt *new;
 227
 228         new = (struct rpc_clnt *)kmalloc(sizeof(*new), GFP_KERNEL);
 229         if (!new)
 230                 goto out_no_clnt;
 231         memcpy(new, clnt, sizeof(*new));
 232         atomic_set(&new->cl_count, 1);
 233         atomic_set(&new->cl_users, 0);
 234         new->cl_parent = clnt;
 235         atomic_inc(&clnt->cl_count);
 236         /* Duplicate portmapper */
 237         rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
 238         /* Turn off autobind on clones */
 239         new->cl_autobind = 0;
 240         new->cl_oneshot = 0;
 241         new->cl_dead = 0;
 242         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 243         if (new->cl_auth)
 244                 atomic_inc(&new->cl_auth->au_count);
 245         new->cl_pmap            = &new->cl_pmap_default;
 246         rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
 247         return new;
 248 out_no_clnt:
 249         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
 250         return ERR_PTR(-ENOMEM);
 251 }
 252
 253 /*
 254  * Properly shut down an RPC client, terminating all outstanding
 255  * requests. Note that we must be certain that cl_oneshot and
 256  * cl_dead are cleared, or else the client would be destroyed
 257  * when the last task releases it.
 258  */
 259 int
 260 rpc_shutdown_client(struct rpc_clnt *clnt)
 261 {
 262         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 263                         clnt->cl_protname, clnt->cl_server,
 264                         atomic_read(&clnt->cl_users));
 265
 266         while (atomic_read(&clnt->cl_users) > 0) {
 267                 /* Don't let rpc_release_client destroy us */
 268                 clnt->cl_oneshot = 0;
 269                 clnt->cl_dead = 0;
 270                 rpc_killall_tasks(clnt);
 271                 sleep_on_timeout(&destroy_wait, 1*HZ);
 272         }
 273
 274         if (atomic_read(&clnt->cl_users) < 0) {
 275                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 276                                 clnt, atomic_read(&clnt->cl_users));
 277 #ifdef RPC_DEBUG
 278                 rpc_show_tasks();
 279 #endif
 280                 BUG();
 281         }
 282
 283         return rpc_destroy_client(clnt);
 284 }
 285
 286 /*
 287  * Delete an RPC client
 288  */
 289 int
 290 rpc_destroy_client(struct rpc_clnt *clnt)
 291 {
 292         if (!atomic_dec_and_test(&clnt->cl_count))
 293                 return 1;
 294         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 295
 296         dprintk("RPC: destroying %s client for %s\n",
 297                         clnt->cl_protname, clnt->cl_server);
 298         if (clnt->cl_auth) {
 299                 rpcauth_destroy(clnt->cl_auth);
 300                 clnt->cl_auth = NULL;
 301         }
 302         if (clnt->cl_parent != clnt) {
 303                 rpc_destroy_client(clnt->cl_parent);
 304                 goto out_free;
 305         }
 306         if (clnt->cl_pathname[0])
 307                 rpc_rmdir(clnt->cl_pathname);
 308         if (clnt->cl_xprt) {
 309                 xprt_destroy(clnt->cl_xprt);
 310                 clnt->cl_xprt = NULL;
 311         }
 312         if (clnt->cl_server != clnt->cl_inline_name)
 313                 kfree(clnt->cl_server);
 314 out_free:
 315         kfree(clnt);
 316         return 0;
 317 }
 318
 319 /*
 320  * Release an RPC client
 321  */
 322 void
 323 rpc_release_client(struct rpc_clnt *clnt)
 324 {
 325         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 326                                 clnt, atomic_read(&clnt->cl_users));
 327
 328         if (!atomic_dec_and_test(&clnt->cl_users))
 329                 return;
 330         wake_up(&destroy_wait);
 331         if (clnt->cl_oneshot || clnt->cl_dead)
 332                 rpc_destroy_client(clnt);
 333 }
 334
 335 /**
 336  * rpc_bind_new_program - bind a new RPC program to an existing client
 337  * @old - old rpc_client
 338  * @program - rpc program to set
 339  * @vers - rpc program version
 340  *
 341  * Clones the rpc client and sets up a new RPC program. This is mainly
 342  * of use for enabling different RPC programs to share the same transport.
 343  * The Sun NFSv2/v3 ACL protocol can do this.
 344  */
 345 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 346                                       struct rpc_program *program,
 347                                       int vers)
 348 {
 349         struct rpc_clnt *clnt;
 350         struct rpc_version *version;
 351         int err;
 352
 353         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 354         version = program->version[vers];
 355         clnt = rpc_clone_client(old);
 356         if (IS_ERR(clnt))
 357                 goto out;
 358         clnt->cl_procinfo = version->procs;
 359         clnt->cl_maxproc  = version->nrprocs;
 360         clnt->cl_protname = program->name;
 361         clnt->cl_prog     = program->number;
 362         clnt->cl_vers     = version->number;
 363         clnt->cl_stats    = program->stats;
 364         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 365         if (err != 0) {
 366                 rpc_shutdown_client(clnt);
 367                 clnt = ERR_PTR(err);
 368         }
 369 out:
 370         return clnt;
 371 }
 372
 373 /*
 374  * Default callback for async RPC calls
 375  */
 376 static void
 377 rpc_default_callback(struct rpc_task *task, void *data)
 378 {
 379 }
 380
 381 static const struct rpc_call_ops rpc_default_ops = {
 382         .rpc_call_done = rpc_default_callback,
 383 };
 384
 385 /*
 386  *      Export the signal mask handling for synchronous code that
 387  *      sleeps on RPC calls
 388  */
 389 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 390
 391 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 392 {
 393         unsigned long   sigallow = sigmask(SIGKILL);
 394         sigset_t sigmask;
 395
 396         /* Block all signals except those listed in sigallow */
 397         if (intr)
 398                 sigallow |= RPC_INTR_SIGNALS;
 399         siginitsetinv(&sigmask, sigallow);
 400         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 401 }
 402
 403 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 404 {
 405         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 406 }
 407
 408 static inline void rpc_restore_sigmask(sigset_t *oldset)
 409 {
 410         sigprocmask(SIG_SETMASK, oldset, NULL);
 411 }
 412
 413 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 414 {
 415         rpc_save_sigmask(oldset, clnt->cl_intr);
 416 }
 417
 418 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 419 {
 420         rpc_restore_sigmask(oldset);
 421 }
 422
 423 /*
 424  * New rpc_call implementation
 425  */
 426 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 427 {
 428         struct rpc_task *task;
 429         sigset_t        oldset;
 430         int             status;
 431
 432         /* If this client is slain all further I/O fails */
 433         if (clnt->cl_dead)
 434                 return -EIO;
 435
 436         BUG_ON(flags & RPC_TASK_ASYNC);
 437
 438         status = -ENOMEM;
 439         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 440         if (task == NULL)
 441                 goto out;
 442
 443         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 444         rpc_task_sigmask(task, &oldset);
 445
 446         rpc_call_setup(task, msg, 0);
 447
 448         /* Set up the call info struct and execute the task */
 449         status = task->tk_status;
 450         if (status == 0) {
 451                 atomic_inc(&task->tk_count);
 452                 status = rpc_execute(task);
 453                 if (status == 0)
 454                         status = task->tk_status;
 455         }
 456         rpc_restore_sigmask(&oldset);
 457         rpc_release_task(task);
 458 out:
 459         return status;
 460 }
 461
 462 /*
 463  * New rpc_call implementation
 464  */
 465 int
 466 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 467                const struct rpc_call_ops *tk_ops, void *data)
 468 {
 469         struct rpc_task *task;
 470         sigset_t        oldset;
 471         int             status;
 472
 473         /* If this client is slain all further I/O fails */
 474         if (clnt->cl_dead)
 475                 return -EIO;
 476
 477         flags |= RPC_TASK_ASYNC;
 478
 479         /* Create/initialize a new RPC task */
 480         status = -ENOMEM;
 481         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 482                 goto out;
 483
 484         /* Mask signals on GSS_AUTH upcalls */
 485         rpc_task_sigmask(task, &oldset);
 486
 487         rpc_call_setup(task, msg, 0);
 488
 489         /* Set up the call info struct and execute the task */
 490         status = task->tk_status;
 491         if (status == 0)
 492                 rpc_execute(task);
 493         else
 494                 rpc_release_task(task);
 495
 496         rpc_restore_sigmask(&oldset);
 497 out:
 498         return status;
 499 }
 500
 501
 502 void
 503 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 504 {
 505         task->tk_msg   = *msg;
 506         task->tk_flags |= flags;
 507         /* Bind the user cred */
 508         if (task->tk_msg.rpc_cred != NULL)
 509                 rpcauth_holdcred(task);
 510         else
 511                 rpcauth_bindcred(task);
 512
 513         if (task->tk_status == 0)
 514                 task->tk_action = call_start;
 515         else
 516                 task->tk_action = rpc_exit_task;
 517 }
 518
 519 void
 520 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 521 {
 522         struct rpc_xprt *xprt = clnt->cl_xprt;
 523         if (xprt->ops->set_buffer_size)
 524                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 525 }
 526
 527 /*
 528  * Return size of largest payload RPC client can support, in bytes
 529  *
 530  * For stream transports, this is one RPC record fragment (see RFC
 531  * 1831), as we don't support multi-record requests yet.  For datagram
 532  * transports, this is the size of an IP packet minus the IP, UDP, and
 533  * RPC header sizes.
 534  */
 535 size_t rpc_max_payload(struct rpc_clnt *clnt)
 536 {
 537         return clnt->cl_xprt->max_payload;
 538 }
 539 EXPORT_SYMBOL(rpc_max_payload);
 540
 541 /*
 542  * Restart an (async) RPC call. Usually called from within the
 543  * exit handler.
 544  */
 545 void
 546 rpc_restart_call(struct rpc_task *task)
 547 {
 548         if (RPC_ASSASSINATED(task))
 549                 return;
 550
 551         task->tk_action = call_start;
 552 }
 553
 554 /*
 555  * 0.  Initial state
 556  *
 557  *     Other FSM states can be visited zero or more times, but
 558  *     this state is visited exactly once for each RPC.
 559  */
 560 static void
 561 call_start(struct rpc_task *task)
 562 {
 563         struct rpc_clnt *clnt = task->tk_client;
 564
 565         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 566                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 567                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 568
 569         /* Increment call count */
 570         task->tk_msg.rpc_proc->p_count++;
 571         clnt->cl_stats->rpccnt++;
 572         task->tk_action = call_reserve;
 573 }
 574
 575 /*
 576  * 1.   Reserve an RPC call slot
 577  */
 578 static void
 579 call_reserve(struct rpc_task *task)
 580 {
 581         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 582
 583         if (!rpcauth_uptodatecred(task)) {
 584                 task->tk_action = call_refresh;
 585                 return;
 586         }
 587
 588         task->tk_status  = 0;
 589         task->tk_action  = call_reserveresult;
 590         xprt_reserve(task);
 591 }
 592
 593 /*
 594  * 1b.  Grok the result of xprt_reserve()
 595  */
 596 static void
 597 call_reserveresult(struct rpc_task *task)
 598 {
 599         int status = task->tk_status;
 600
 601         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 602                                 task->tk_pid, task->tk_status);
 603
 604         /*
 605          * After a call to xprt_reserve(), we must have either
 606          * a request slot or else an error status.
 607          */
 608         task->tk_status = 0;
 609         if (status >= 0) {
 610                 if (task->tk_rqstp) {
 611                         task->tk_action = call_allocate;
 612                         return;
 613                 }
 614
 615                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 616                                 __FUNCTION__, status);
 617                 rpc_exit(task, -EIO);
 618                 return;
 619         }
 620
 621         /*
 622          * Even though there was an error, we may have acquired
 623          * a request slot somehow.  Make sure not to leak it.
 624          */
 625         if (task->tk_rqstp) {
 626                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 627                                 __FUNCTION__, status);
 628                 xprt_release(task);
 629         }
 630
 631         switch (status) {
 632         case -EAGAIN:   /* woken up; retry */
 633                 task->tk_action = call_reserve;
 634                 return;
 635         case -EIO:      /* probably a shutdown */
 636                 break;
 637         default:
 638                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 639                                 __FUNCTION__, status);
 640                 break;
 641         }
 642         rpc_exit(task, status);
 643 }
 644
 645 /*
 646  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 647  *      (Note: buffer memory is freed in rpc_task_release).
 648  */
 649 static void
 650 call_allocate(struct rpc_task *task)
 651 {
 652         unsigned int    bufsiz;
 653
 654         dprintk("RPC: %4d call_allocate (status %d)\n",
 655                                 task->tk_pid, task->tk_status);
 656         task->tk_action = call_bind;
 657         if (task->tk_buffer)
 658                 return;
 659
 660         /* FIXME: compute buffer requirements more exactly using
 661          * auth->au_wslack */
 662         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 663
 664         if (rpc_malloc(task, bufsiz << 1) != NULL)
 665                 return;
 666         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 667
 668         if (RPC_IS_ASYNC(task) || !signalled()) {
 669                 xprt_release(task);
 670                 task->tk_action = call_reserve;
 671                 rpc_delay(task, HZ>>4);
 672                 return;
 673         }
 674
 675         rpc_exit(task, -ERESTARTSYS);
 676 }
 677
 678 static inline int
 679 rpc_task_need_encode(struct rpc_task *task)
 680 {
 681         return task->tk_rqstp->rq_snd_buf.len == 0;
 682 }
 683
 684 static inline void
 685 rpc_task_force_reencode(struct rpc_task *task)
 686 {
 687         task->tk_rqstp->rq_snd_buf.len = 0;
 688 }
 689
 690 /*
 691  * 3.   Encode arguments of an RPC call
 692  */
 693 static void
 694 call_encode(struct rpc_task *task)
 695 {
 696         struct rpc_rqst *req = task->tk_rqstp;
 697         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 698         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 699         unsigned int    bufsiz;
 700         kxdrproc_t      encode;
 701         u32             *p;
 702
 703         dprintk("RPC: %4d call_encode (status %d)\n",
 704                                 task->tk_pid, task->tk_status);
 705
 706         /* Default buffer setup */
 707         bufsiz = task->tk_bufsize >> 1;
 708         sndbuf->head[0].iov_base = (void *)task->tk_buffer;
 709         sndbuf->head[0].iov_len  = bufsiz;
 710         sndbuf->tail[0].iov_len  = 0;
 711         sndbuf->page_len         = 0;
 712         sndbuf->len              = 0;
 713         sndbuf->buflen           = bufsiz;
 714         rcvbuf->head[0].iov_base = (void *)((char *)task->tk_buffer + bufsiz);
 715         rcvbuf->head[0].iov_len  = bufsiz;
 716         rcvbuf->tail[0].iov_len  = 0;
 717         rcvbuf->page_len         = 0;
 718         rcvbuf->len              = 0;
 719         rcvbuf->buflen           = bufsiz;
 720
 721         /* Encode header and provided arguments */
 722         encode = task->tk_msg.rpc_proc->p_encode;
 723         if (!(p = call_header(task))) {
 724                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 725                 rpc_exit(task, -EIO);
 726                 return;
 727         }
 728         if (encode == NULL)
 729                 return;
 730
 731         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 732                         task->tk_msg.rpc_argp);
 733         if (task->tk_status == -ENOMEM) {
 734                 /* XXX: Is this sane? */
 735                 rpc_delay(task, 3*HZ);
 736                 task->tk_status = -EAGAIN;
 737         }
 738 }
 739
 740 /*
 741  * 4.   Get the server port number if not yet set
 742  */
 743 static void
 744 call_bind(struct rpc_task *task)
 745 {
 746         struct rpc_clnt *clnt = task->tk_client;
 747
 748         dprintk("RPC: %4d call_bind (status %d)\n",
 749                                 task->tk_pid, task->tk_status);
 750
 751         task->tk_action = call_connect;
 752         if (!clnt->cl_port) {
 753                 task->tk_action = call_bind_status;
 754                 task->tk_timeout = task->tk_xprt->bind_timeout;
 755                 rpc_getport(task, clnt);
 756         }
 757 }
 758
 759 /*
 760  * 4a.  Sort out bind result
 761  */
 762 static void
 763 call_bind_status(struct rpc_task *task)
 764 {
 765         int status = -EACCES;
 766
 767         if (task->tk_status >= 0) {
 768                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 769                                         task->tk_pid, task->tk_status);
 770                 task->tk_status = 0;
 771                 task->tk_action = call_connect;
 772                 return;
 773         }
 774
 775         switch (task->tk_status) {
 776         case -EACCES:
 777                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 778                                 task->tk_pid);
 779                 rpc_delay(task, 3*HZ);
 780                 goto retry_bind;
 781         case -ETIMEDOUT:
 782                 dprintk("RPC: %4d rpcbind request timed out\n",
 783                                 task->tk_pid);
 784                 if (RPC_IS_SOFT(task)) {
 785                         status = -EIO;
 786                         break;
 787                 }
 788                 goto retry_bind;
 789         case -EPFNOSUPPORT:
 790                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 791                                 task->tk_pid);
 792                 break;
 793         case -EPROTONOSUPPORT:
 794                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 795                                 task->tk_pid);
 796                 break;
 797         default:
 798                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 799                                 task->tk_pid, -task->tk_status);
 800                 status = -EIO;
 801                 break;
 802         }
 803
 804         rpc_exit(task, status);
 805         return;
 806
 807 retry_bind:
 808         task->tk_status = 0;
 809         task->tk_action = call_bind;
 810         return;
 811 }
 812
 813 /*
 814  * 4b.  Connect to the RPC server
 815  */
 816 static void
 817 call_connect(struct rpc_task *task)
 818 {
 819         struct rpc_xprt *xprt = task->tk_xprt;
 820
 821         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 822                         task->tk_pid, xprt,
 823                         (xprt_connected(xprt) ? "is" : "is not"));
 824
 825         task->tk_action = call_transmit;
 826         if (!xprt_connected(xprt)) {
 827                 task->tk_action = call_connect_status;
 828                 if (task->tk_status < 0)
 829                         return;
 830                 xprt_connect(task);
 831         }
 832 }
 833
 834 /*
 835  * 4c.  Sort out connect result
 836  */
 837 static void
 838 call_connect_status(struct rpc_task *task)
 839 {
 840         struct rpc_clnt *clnt = task->tk_client;
 841         int status = task->tk_status;
 842
 843         dprintk("RPC: %5u call_connect_status (status %d)\n",
 844                                 task->tk_pid, task->tk_status);
 845
 846         task->tk_status = 0;
 847         if (status >= 0) {
 848                 clnt->cl_stats->netreconn++;
 849                 task->tk_action = call_transmit;
 850                 return;
 851         }
 852
 853         /* Something failed: remote service port may have changed */
 854         if (clnt->cl_autobind)
 855                 clnt->cl_port = 0;
 856
 857         switch (status) {
 858         case -ENOTCONN:
 859         case -ETIMEDOUT:
 860         case -EAGAIN:
 861                 task->tk_action = call_bind;
 862                 break;
 863         default:
 864                 rpc_exit(task, -EIO);
 865                 break;
 866         }
 867 }
 868
 869 /*
 870  * 5.   Transmit the RPC request, and wait for reply
 871  */
 872 static void
 873 call_transmit(struct rpc_task *task)
 874 {
 875         dprintk("RPC: %4d call_transmit (status %d)\n",
 876                                 task->tk_pid, task->tk_status);
 877
 878         task->tk_action = call_status;
 879         if (task->tk_status < 0)
 880                 return;
 881         task->tk_status = xprt_prepare_transmit(task);
 882         if (task->tk_status != 0)
 883                 return;
 884         /* Encode here so that rpcsec_gss can use correct sequence number. */
 885         if (rpc_task_need_encode(task)) {
 886                 task->tk_rqstp->rq_bytes_sent = 0;
 887                 call_encode(task);
 888                 /* Did the encode result in an error condition? */
 889                 if (task->tk_status != 0)
 890                         goto out_nosend;
 891         }
 892         task->tk_action = call_transmit_status;
 893         xprt_transmit(task);
 894         if (task->tk_status < 0)
 895                 return;
 896         if (!task->tk_msg.rpc_proc->p_decode) {
 897                 task->tk_action = rpc_exit_task;
 898                 rpc_wake_up_task(task);
 899         }
 900         return;
 901 out_nosend:
 902         /* release socket write lock before attempting to handle error */
 903         xprt_abort_transmit(task);
 904         rpc_task_force_reencode(task);
 905 }
 906
 907 /*
 908  * 6.   Sort out the RPC call status
 909  */
 910 static void
 911 call_status(struct rpc_task *task)
 912 {
 913         struct rpc_clnt *clnt = task->tk_client;
 914         struct rpc_rqst *req = task->tk_rqstp;
 915         int             status;
 916
 917         if (req->rq_received > 0 && !req->rq_bytes_sent)
 918                 task->tk_status = req->rq_received;
 919
 920         dprintk("RPC: %4d call_status (status %d)\n",
 921                                 task->tk_pid, task->tk_status);
 922
 923         status = task->tk_status;
 924         if (status >= 0) {
 925                 task->tk_action = call_decode;
 926                 return;
 927         }
 928
 929         task->tk_status = 0;
 930         switch(status) {
 931         case -ETIMEDOUT:
 932                 task->tk_action = call_timeout;
 933                 break;
 934         case -ECONNREFUSED:
 935         case -ENOTCONN:
 936                 if (clnt->cl_autobind)
 937                         clnt->cl_port = 0;
 938                 task->tk_action = call_bind;
 939                 break;
 940         case -EAGAIN:
 941                 task->tk_action = call_transmit;
 942                 break;
 943         case -EIO:
 944                 /* shutdown or soft timeout */
 945                 rpc_exit(task, status);
 946                 break;
 947         default:
 948                 if (clnt->cl_chatty)
 949                         printk("%s: RPC call returned error %d\n",
 950                                clnt->cl_protname, -status);
 951                 rpc_exit(task, status);
 952                 break;
 953         }
 954 }
 955
 956 /*
 957  * 6a.  Handle transmission errors.
 958  */
 959 static void
 960 call_transmit_status(struct rpc_task *task)
 961 {
 962         if (task->tk_status != -EAGAIN)
 963                 rpc_task_force_reencode(task);
 964         call_status(task);
 965 }
 966
 967 /*
 968  * 6b.  Handle RPC timeout
 969  *      We do not release the request slot, so we keep using the
 970  *      same XID for all retransmits.
 971  */
 972 static void
 973 call_timeout(struct rpc_task *task)
 974 {
 975         struct rpc_clnt *clnt = task->tk_client;
 976
 977         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
 978                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
 979                 goto retry;
 980         }
 981
 982         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
 983         if (RPC_IS_SOFT(task)) {
 984                 if (clnt->cl_chatty)
 985                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
 986                                 clnt->cl_protname, clnt->cl_server);
 987                 rpc_exit(task, -EIO);
 988                 return;
 989         }
 990
 991         if (clnt->cl_chatty && !(task->tk_flags & RPC_CALL_MAJORSEEN)) {
 992                 task->tk_flags |= RPC_CALL_MAJORSEEN;
 993                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
 994                         clnt->cl_protname, clnt->cl_server);
 995         }
 996         if (clnt->cl_autobind)
 997                 clnt->cl_port = 0;
 998
 999 retry:
1000         clnt->cl_stats->rpcretrans++;
1001         task->tk_action = call_bind;
1002         task->tk_status = 0;
1003 }
1004
1005 /*
1006  * 7.   Decode the RPC reply
1007  */
1008 static void
1009 call_decode(struct rpc_task *task)
1010 {
1011         struct rpc_clnt *clnt = task->tk_client;
1012         struct rpc_rqst *req = task->tk_rqstp;
1013         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1014         u32             *p;
1015
1016         dprintk("RPC: %4d call_decode (status %d)\n",
1017                                 task->tk_pid, task->tk_status);
1018
1019         if (clnt->cl_chatty && (task->tk_flags & RPC_CALL_MAJORSEEN)) {
1020                 printk(KERN_NOTICE "%s: server %s OK\n",
1021                         clnt->cl_protname, clnt->cl_server);
1022                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1023         }
1024
1025         if (task->tk_status < 12) {
1026                 if (!RPC_IS_SOFT(task)) {
1027                         task->tk_action = call_bind;
1028                         clnt->cl_stats->rpcretrans++;
1029                         goto out_retry;
1030                 }
1031                 printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1032                         clnt->cl_protname, task->tk_status);
1033                 rpc_exit(task, -EIO);
1034                 return;
1035         }
1036
1037         req->rq_rcv_buf.len = req->rq_private_buf.len;
1038
1039         /* Check that the softirq receive buffer is valid */
1040         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1041                                 sizeof(req->rq_rcv_buf)) != 0);
1042
1043         /* Verify the RPC header */
1044         p = call_verify(task);
1045         if (IS_ERR(p)) {
1046                 if (p == ERR_PTR(-EAGAIN))
1047                         goto out_retry;
1048                 return;
1049         }
1050
1051         task->tk_action = rpc_exit_task;
1052
1053         if (decode)
1054                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1055                                                       task->tk_msg.rpc_resp);
1056         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1057                                         task->tk_status);
1058         return;
1059 out_retry:
1060         req->rq_received = req->rq_private_buf.len = 0;
1061         task->tk_status = 0;
1062 }
1063
1064 /*
1065  * 8.   Refresh the credentials if rejected by the server
1066  */
1067 static void
1068 call_refresh(struct rpc_task *task)
1069 {
1070         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1071
1072         xprt_release(task);     /* Must do to obtain new XID */
1073         task->tk_action = call_refreshresult;
1074         task->tk_status = 0;
1075         task->tk_client->cl_stats->rpcauthrefresh++;
1076         rpcauth_refreshcred(task);
1077 }
1078
1079 /*
1080  * 8a.  Process the results of a credential refresh
1081  */
1082 static void
1083 call_refreshresult(struct rpc_task *task)
1084 {
1085         int status = task->tk_status;
1086         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1087                                 task->tk_pid, task->tk_status);
1088
1089         task->tk_status = 0;
1090         task->tk_action = call_reserve;
1091         if (status >= 0 && rpcauth_uptodatecred(task))
1092                 return;
1093         if (status == -EACCES) {
1094                 rpc_exit(task, -EACCES);
1095                 return;
1096         }
1097         task->tk_action = call_refresh;
1098         if (status != -ETIMEDOUT)
1099                 rpc_delay(task, 3*HZ);
1100         return;
1101 }
1102
1103 /*
1104  * Call header serialization
1105  */
1106 static u32 *
1107 call_header(struct rpc_task *task)
1108 {
1109         struct rpc_clnt *clnt = task->tk_client;
1110         struct rpc_rqst *req = task->tk_rqstp;
1111         u32             *p = req->rq_svec[0].iov_base;
1112
1113         /* FIXME: check buffer size? */
1114
1115         p = xprt_skip_transport_header(task->tk_xprt, p);
1116         *p++ = req->rq_xid;             /* XID */
1117         *p++ = htonl(RPC_CALL);         /* CALL */
1118         *p++ = htonl(RPC_VERSION);      /* RPC version */
1119         *p++ = htonl(clnt->cl_prog);    /* program number */
1120         *p++ = htonl(clnt->cl_vers);    /* program version */
1121         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1122         p = rpcauth_marshcred(task, p);
1123         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1124         return p;
1125 }
1126
1127 /*
1128  * Reply header verification
1129  */
1130 static u32 *
1131 call_verify(struct rpc_task *task)
1132 {
1133         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1134         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1135         u32     *p = iov->iov_base, n;
1136         int error = -EACCES;
1137
1138         if ((len -= 3) < 0)
1139                 goto out_overflow;
1140         p += 1; /* skip XID */
1141
1142         if ((n = ntohl(*p++)) != RPC_REPLY) {
1143                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1144                 goto out_garbage;
1145         }
1146         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1147                 if (--len < 0)
1148                         goto out_overflow;
1149                 switch ((n = ntohl(*p++))) {
1150                         case RPC_AUTH_ERROR:
1151                                 break;
1152                         case RPC_MISMATCH:
1153                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1154                                 error = -EPROTONOSUPPORT;
1155                                 goto out_err;
1156                         default:
1157                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1158                                 goto out_eio;
1159                 }
1160                 if (--len < 0)
1161                         goto out_overflow;
1162                 switch ((n = ntohl(*p++))) {
1163                 case RPC_AUTH_REJECTEDCRED:
1164                 case RPC_AUTH_REJECTEDVERF:
1165                 case RPCSEC_GSS_CREDPROBLEM:
1166                 case RPCSEC_GSS_CTXPROBLEM:
1167                         if (!task->tk_cred_retry)
1168                                 break;
1169                         task->tk_cred_retry--;
1170                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1171                                                         task->tk_pid);
1172                         rpcauth_invalcred(task);
1173                         task->tk_action = call_refresh;
1174                         goto out_retry;
1175                 case RPC_AUTH_BADCRED:
1176                 case RPC_AUTH_BADVERF:
1177                         /* possibly garbled cred/verf? */
1178                         if (!task->tk_garb_retry)
1179                                 break;
1180                         task->tk_garb_retry--;
1181                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1182                                                         task->tk_pid);
1183                         task->tk_action = call_bind;
1184                         goto out_retry;
1185                 case RPC_AUTH_TOOWEAK:
1186                         printk(KERN_NOTICE "call_verify: server requires stronger "
1187                                "authentication.\n");
1188                         break;
1189                 default:
1190                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1191                         error = -EIO;
1192                 }
1193                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1194                                                 task->tk_pid, n);
1195                 goto out_err;
1196         }
1197         if (!(p = rpcauth_checkverf(task, p))) {
1198                 printk(KERN_WARNING "call_verify: auth check failed\n");
1199                 goto out_garbage;               /* bad verifier, retry */
1200         }
1201         len = p - (u32 *)iov->iov_base - 1;
1202         if (len < 0)
1203                 goto out_overflow;
1204         switch ((n = ntohl(*p++))) {
1205         case RPC_SUCCESS:
1206                 return p;
1207         case RPC_PROG_UNAVAIL:
1208                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1209                                 (unsigned int)task->tk_client->cl_prog,
1210                                 task->tk_client->cl_server);
1211                 error = -EPFNOSUPPORT;
1212                 goto out_err;
1213         case RPC_PROG_MISMATCH:
1214                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1215                                 (unsigned int)task->tk_client->cl_prog,
1216                                 (unsigned int)task->tk_client->cl_vers,
1217                                 task->tk_client->cl_server);
1218                 error = -EPROTONOSUPPORT;
1219                 goto out_err;
1220         case RPC_PROC_UNAVAIL:
1221                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1222                                 task->tk_msg.rpc_proc,
1223                                 task->tk_client->cl_prog,
1224                                 task->tk_client->cl_vers,
1225                                 task->tk_client->cl_server);
1226                 error = -EOPNOTSUPP;
1227                 goto out_err;
1228         case RPC_GARBAGE_ARGS:
1229                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1230                 break;                  /* retry */
1231         default:
1232                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1233                 /* Also retry */
1234         }
1235
1236 out_garbage:
1237         task->tk_client->cl_stats->rpcgarbage++;
1238         if (task->tk_garb_retry) {
1239                 task->tk_garb_retry--;
1240                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1241                 task->tk_action = call_bind;
1242 out_retry:
1243                 return ERR_PTR(-EAGAIN);
1244         }
1245         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1246 out_eio:
1247         error = -EIO;
1248 out_err:
1249         rpc_exit(task, error);
1250         return ERR_PTR(error);
1251 out_overflow:
1252         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1253         goto out_garbage;
1254 }
1255
1256 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1257 {
1258         return 0;
1259 }
1260
1261 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1262 {
1263         return 0;
1264 }
1265
1266 static struct rpc_procinfo rpcproc_null = {
1267         .p_encode = rpcproc_encode_null,
1268         .p_decode = rpcproc_decode_null,
1269 };
1270
1271 int rpc_ping(struct rpc_clnt *clnt, int flags)
1272 {
1273         struct rpc_message msg = {
1274                 .rpc_proc = &rpcproc_null,
1275         };
1276         int err;
1277         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1278         err = rpc_call_sync(clnt, &msg, flags);
1279         put_rpccred(msg.rpc_cred);
1280         return err;
1281 }