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_no_xprt;
 117         if (vers >= program->nrvers || !(version = program->version[vers]))
 118                 goto out_err;
 119
 120         err = -ENOMEM;
 121         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 out_no_xprt:
 186         return ERR_PTR(err);
 187 }
 188
 189 /**
 190  * Create an RPC client
 191  * @xprt - pointer to xprt struct
 192  * @servname - name of server
 193  * @info - rpc_program
 194  * @version - rpc_program version
 195  * @authflavor - rpc_auth flavour to use
 196  *
 197  * Creates an RPC client structure, then pings the server in order to
 198  * determine if it is up, and if it supports this program and version.
 199  *
 200  * This function should never be called by asynchronous tasks such as
 201  * the portmapper.
 202  */
 203 struct rpc_clnt *rpc_create_client(struct rpc_xprt *xprt, char *servname,
 204                 struct rpc_program *info, u32 version, rpc_authflavor_t authflavor)
 205 {
 206         struct rpc_clnt *clnt;
 207         int err;
 208
 209         clnt = rpc_new_client(xprt, servname, info, version, authflavor);
 210         if (IS_ERR(clnt))
 211                 return clnt;
 212         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 213         if (err == 0)
 214                 return clnt;
 215         rpc_shutdown_client(clnt);
 216         return ERR_PTR(err);
 217 }
 218
 219 /*
 220  * This function clones the RPC client structure. It allows us to share the
 221  * same transport while varying parameters such as the authentication
 222  * flavour.
 223  */
 224 struct rpc_clnt *
 225 rpc_clone_client(struct rpc_clnt *clnt)
 226 {
 227         struct rpc_clnt *new;
 228
 229         new = kmalloc(sizeof(*new), GFP_KERNEL);
 230         if (!new)
 231                 goto out_no_clnt;
 232         memcpy(new, clnt, sizeof(*new));
 233         atomic_set(&new->cl_count, 1);
 234         atomic_set(&new->cl_users, 0);
 235         new->cl_parent = clnt;
 236         atomic_inc(&clnt->cl_count);
 237         /* Duplicate portmapper */
 238         rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
 239         /* Turn off autobind on clones */
 240         new->cl_autobind = 0;
 241         new->cl_oneshot = 0;
 242         new->cl_dead = 0;
 243         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 244         if (new->cl_auth)
 245                 atomic_inc(&new->cl_auth->au_count);
 246         new->cl_pmap            = &new->cl_pmap_default;
 247         rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
 248         return new;
 249 out_no_clnt:
 250         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
 251         return ERR_PTR(-ENOMEM);
 252 }
 253
 254 /*
 255  * Properly shut down an RPC client, terminating all outstanding
 256  * requests. Note that we must be certain that cl_oneshot and
 257  * cl_dead are cleared, or else the client would be destroyed
 258  * when the last task releases it.
 259  */
 260 int
 261 rpc_shutdown_client(struct rpc_clnt *clnt)
 262 {
 263         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 264                         clnt->cl_protname, clnt->cl_server,
 265                         atomic_read(&clnt->cl_users));
 266
 267         while (atomic_read(&clnt->cl_users) > 0) {
 268                 /* Don't let rpc_release_client destroy us */
 269                 clnt->cl_oneshot = 0;
 270                 clnt->cl_dead = 0;
 271                 rpc_killall_tasks(clnt);
 272                 wait_event_timeout(destroy_wait,
 273                         !atomic_read(&clnt->cl_users), 1*HZ);
 274         }
 275
 276         if (atomic_read(&clnt->cl_users) < 0) {
 277                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 278                                 clnt, atomic_read(&clnt->cl_users));
 279 #ifdef RPC_DEBUG
 280                 rpc_show_tasks();
 281 #endif
 282                 BUG();
 283         }
 284
 285         return rpc_destroy_client(clnt);
 286 }
 287
 288 /*
 289  * Delete an RPC client
 290  */
 291 int
 292 rpc_destroy_client(struct rpc_clnt *clnt)
 293 {
 294         if (!atomic_dec_and_test(&clnt->cl_count))
 295                 return 1;
 296         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 297
 298         dprintk("RPC: destroying %s client for %s\n",
 299                         clnt->cl_protname, clnt->cl_server);
 300         if (clnt->cl_auth) {
 301                 rpcauth_destroy(clnt->cl_auth);
 302                 clnt->cl_auth = NULL;
 303         }
 304         if (clnt->cl_parent != clnt) {
 305                 rpc_destroy_client(clnt->cl_parent);
 306                 goto out_free;
 307         }
 308         if (clnt->cl_pathname[0])
 309                 rpc_rmdir(clnt->cl_pathname);
 310         if (clnt->cl_xprt) {
 311                 xprt_destroy(clnt->cl_xprt);
 312                 clnt->cl_xprt = NULL;
 313         }
 314         if (clnt->cl_server != clnt->cl_inline_name)
 315                 kfree(clnt->cl_server);
 316 out_free:
 317         kfree(clnt);
 318         return 0;
 319 }
 320
 321 /*
 322  * Release an RPC client
 323  */
 324 void
 325 rpc_release_client(struct rpc_clnt *clnt)
 326 {
 327         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 328                                 clnt, atomic_read(&clnt->cl_users));
 329
 330         if (!atomic_dec_and_test(&clnt->cl_users))
 331                 return;
 332         wake_up(&destroy_wait);
 333         if (clnt->cl_oneshot || clnt->cl_dead)
 334                 rpc_destroy_client(clnt);
 335 }
 336
 337 /**
 338  * rpc_bind_new_program - bind a new RPC program to an existing client
 339  * @old - old rpc_client
 340  * @program - rpc program to set
 341  * @vers - rpc program version
 342  *
 343  * Clones the rpc client and sets up a new RPC program. This is mainly
 344  * of use for enabling different RPC programs to share the same transport.
 345  * The Sun NFSv2/v3 ACL protocol can do this.
 346  */
 347 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 348                                       struct rpc_program *program,
 349                                       int vers)
 350 {
 351         struct rpc_clnt *clnt;
 352         struct rpc_version *version;
 353         int err;
 354
 355         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 356         version = program->version[vers];
 357         clnt = rpc_clone_client(old);
 358         if (IS_ERR(clnt))
 359                 goto out;
 360         clnt->cl_procinfo = version->procs;
 361         clnt->cl_maxproc  = version->nrprocs;
 362         clnt->cl_protname = program->name;
 363         clnt->cl_prog     = program->number;
 364         clnt->cl_vers     = version->number;
 365         clnt->cl_stats    = program->stats;
 366         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 367         if (err != 0) {
 368                 rpc_shutdown_client(clnt);
 369                 clnt = ERR_PTR(err);
 370         }
 371 out:
 372         return clnt;
 373 }
 374
 375 /*
 376  * Default callback for async RPC calls
 377  */
 378 static void
 379 rpc_default_callback(struct rpc_task *task, void *data)
 380 {
 381 }
 382
 383 static const struct rpc_call_ops rpc_default_ops = {
 384         .rpc_call_done = rpc_default_callback,
 385 };
 386
 387 /*
 388  *      Export the signal mask handling for synchronous code that
 389  *      sleeps on RPC calls
 390  */
 391 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 392
 393 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 394 {
 395         unsigned long   sigallow = sigmask(SIGKILL);
 396         sigset_t sigmask;
 397
 398         /* Block all signals except those listed in sigallow */
 399         if (intr)
 400                 sigallow |= RPC_INTR_SIGNALS;
 401         siginitsetinv(&sigmask, sigallow);
 402         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 403 }
 404
 405 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 406 {
 407         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 408 }
 409
 410 static inline void rpc_restore_sigmask(sigset_t *oldset)
 411 {
 412         sigprocmask(SIG_SETMASK, oldset, NULL);
 413 }
 414
 415 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 416 {
 417         rpc_save_sigmask(oldset, clnt->cl_intr);
 418 }
 419
 420 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 421 {
 422         rpc_restore_sigmask(oldset);
 423 }
 424
 425 /*
 426  * New rpc_call implementation
 427  */
 428 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 429 {
 430         struct rpc_task *task;
 431         sigset_t        oldset;
 432         int             status;
 433
 434         /* If this client is slain all further I/O fails */
 435         if (clnt->cl_dead)
 436                 return -EIO;
 437
 438         BUG_ON(flags & RPC_TASK_ASYNC);
 439
 440         status = -ENOMEM;
 441         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 442         if (task == NULL)
 443                 goto out;
 444
 445         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 446         rpc_task_sigmask(task, &oldset);
 447
 448         rpc_call_setup(task, msg, 0);
 449
 450         /* Set up the call info struct and execute the task */
 451         status = task->tk_status;
 452         if (status == 0) {
 453                 atomic_inc(&task->tk_count);
 454                 status = rpc_execute(task);
 455                 if (status == 0)
 456                         status = task->tk_status;
 457         }
 458         rpc_restore_sigmask(&oldset);
 459         rpc_release_task(task);
 460 out:
 461         return status;
 462 }
 463
 464 /*
 465  * New rpc_call implementation
 466  */
 467 int
 468 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 469                const struct rpc_call_ops *tk_ops, void *data)
 470 {
 471         struct rpc_task *task;
 472         sigset_t        oldset;
 473         int             status;
 474
 475         /* If this client is slain all further I/O fails */
 476         if (clnt->cl_dead)
 477                 return -EIO;
 478
 479         flags |= RPC_TASK_ASYNC;
 480
 481         /* Create/initialize a new RPC task */
 482         status = -ENOMEM;
 483         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 484                 goto out;
 485
 486         /* Mask signals on GSS_AUTH upcalls */
 487         rpc_task_sigmask(task, &oldset);
 488
 489         rpc_call_setup(task, msg, 0);
 490
 491         /* Set up the call info struct and execute the task */
 492         status = task->tk_status;
 493         if (status == 0)
 494                 rpc_execute(task);
 495         else
 496                 rpc_release_task(task);
 497
 498         rpc_restore_sigmask(&oldset);
 499 out:
 500         return status;
 501 }
 502
 503
 504 void
 505 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 506 {
 507         task->tk_msg   = *msg;
 508         task->tk_flags |= flags;
 509         /* Bind the user cred */
 510         if (task->tk_msg.rpc_cred != NULL)
 511                 rpcauth_holdcred(task);
 512         else
 513                 rpcauth_bindcred(task);
 514
 515         if (task->tk_status == 0)
 516                 task->tk_action = call_start;
 517         else
 518                 task->tk_action = rpc_exit_task;
 519 }
 520
 521 void
 522 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 523 {
 524         struct rpc_xprt *xprt = clnt->cl_xprt;
 525         if (xprt->ops->set_buffer_size)
 526                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 527 }
 528
 529 /*
 530  * Return size of largest payload RPC client can support, in bytes
 531  *
 532  * For stream transports, this is one RPC record fragment (see RFC
 533  * 1831), as we don't support multi-record requests yet.  For datagram
 534  * transports, this is the size of an IP packet minus the IP, UDP, and
 535  * RPC header sizes.
 536  */
 537 size_t rpc_max_payload(struct rpc_clnt *clnt)
 538 {
 539         return clnt->cl_xprt->max_payload;
 540 }
 541 EXPORT_SYMBOL(rpc_max_payload);
 542
 543 /**
 544  * rpc_force_rebind - force transport to check that remote port is unchanged
 545  * @clnt: client to rebind
 546  *
 547  */
 548 void rpc_force_rebind(struct rpc_clnt *clnt)
 549 {
 550         if (clnt->cl_autobind)
 551                 clnt->cl_port = 0;
 552 }
 553 EXPORT_SYMBOL(rpc_force_rebind);
 554
 555 /*
 556  * Restart an (async) RPC call. Usually called from within the
 557  * exit handler.
 558  */
 559 void
 560 rpc_restart_call(struct rpc_task *task)
 561 {
 562         if (RPC_ASSASSINATED(task))
 563                 return;
 564
 565         task->tk_action = call_start;
 566 }
 567
 568 /*
 569  * 0.  Initial state
 570  *
 571  *     Other FSM states can be visited zero or more times, but
 572  *     this state is visited exactly once for each RPC.
 573  */
 574 static void
 575 call_start(struct rpc_task *task)
 576 {
 577         struct rpc_clnt *clnt = task->tk_client;
 578
 579         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 580                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 581                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 582
 583         /* Increment call count */
 584         task->tk_msg.rpc_proc->p_count++;
 585         clnt->cl_stats->rpccnt++;
 586         task->tk_action = call_reserve;
 587 }
 588
 589 /*
 590  * 1.   Reserve an RPC call slot
 591  */
 592 static void
 593 call_reserve(struct rpc_task *task)
 594 {
 595         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 596
 597         if (!rpcauth_uptodatecred(task)) {
 598                 task->tk_action = call_refresh;
 599                 return;
 600         }
 601
 602         task->tk_status  = 0;
 603         task->tk_action  = call_reserveresult;
 604         xprt_reserve(task);
 605 }
 606
 607 /*
 608  * 1b.  Grok the result of xprt_reserve()
 609  */
 610 static void
 611 call_reserveresult(struct rpc_task *task)
 612 {
 613         int status = task->tk_status;
 614
 615         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 616                                 task->tk_pid, task->tk_status);
 617
 618         /*
 619          * After a call to xprt_reserve(), we must have either
 620          * a request slot or else an error status.
 621          */
 622         task->tk_status = 0;
 623         if (status >= 0) {
 624                 if (task->tk_rqstp) {
 625                         task->tk_action = call_allocate;
 626                         return;
 627                 }
 628
 629                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 630                                 __FUNCTION__, status);
 631                 rpc_exit(task, -EIO);
 632                 return;
 633         }
 634
 635         /*
 636          * Even though there was an error, we may have acquired
 637          * a request slot somehow.  Make sure not to leak it.
 638          */
 639         if (task->tk_rqstp) {
 640                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 641                                 __FUNCTION__, status);
 642                 xprt_release(task);
 643         }
 644
 645         switch (status) {
 646         case -EAGAIN:   /* woken up; retry */
 647                 task->tk_action = call_reserve;
 648                 return;
 649         case -EIO:      /* probably a shutdown */
 650                 break;
 651         default:
 652                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 653                                 __FUNCTION__, status);
 654                 break;
 655         }
 656         rpc_exit(task, status);
 657 }
 658
 659 /*
 660  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 661  *      (Note: buffer memory is freed in xprt_release).
 662  */
 663 static void
 664 call_allocate(struct rpc_task *task)
 665 {
 666         struct rpc_rqst *req = task->tk_rqstp;
 667         struct rpc_xprt *xprt = task->tk_xprt;
 668         unsigned int    bufsiz;
 669
 670         dprintk("RPC: %4d call_allocate (status %d)\n",
 671                                 task->tk_pid, task->tk_status);
 672         task->tk_action = call_bind;
 673         if (req->rq_buffer)
 674                 return;
 675
 676         /* FIXME: compute buffer requirements more exactly using
 677          * auth->au_wslack */
 678         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 679
 680         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 681                 return;
 682         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 683
 684         if (RPC_IS_ASYNC(task) || !signalled()) {
 685                 xprt_release(task);
 686                 task->tk_action = call_reserve;
 687                 rpc_delay(task, HZ>>4);
 688                 return;
 689         }
 690
 691         rpc_exit(task, -ERESTARTSYS);
 692 }
 693
 694 static inline int
 695 rpc_task_need_encode(struct rpc_task *task)
 696 {
 697         return task->tk_rqstp->rq_snd_buf.len == 0;
 698 }
 699
 700 static inline void
 701 rpc_task_force_reencode(struct rpc_task *task)
 702 {
 703         task->tk_rqstp->rq_snd_buf.len = 0;
 704 }
 705
 706 /*
 707  * 3.   Encode arguments of an RPC call
 708  */
 709 static void
 710 call_encode(struct rpc_task *task)
 711 {
 712         struct rpc_rqst *req = task->tk_rqstp;
 713         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 714         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 715         unsigned int    bufsiz;
 716         kxdrproc_t      encode;
 717         u32             *p;
 718
 719         dprintk("RPC: %4d call_encode (status %d)\n",
 720                                 task->tk_pid, task->tk_status);
 721
 722         /* Default buffer setup */
 723         bufsiz = req->rq_bufsize >> 1;
 724         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 725         sndbuf->head[0].iov_len  = bufsiz;
 726         sndbuf->tail[0].iov_len  = 0;
 727         sndbuf->page_len         = 0;
 728         sndbuf->len              = 0;
 729         sndbuf->buflen           = bufsiz;
 730         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 731         rcvbuf->head[0].iov_len  = bufsiz;
 732         rcvbuf->tail[0].iov_len  = 0;
 733         rcvbuf->page_len         = 0;
 734         rcvbuf->len              = 0;
 735         rcvbuf->buflen           = bufsiz;
 736
 737         /* Encode header and provided arguments */
 738         encode = task->tk_msg.rpc_proc->p_encode;
 739         if (!(p = call_header(task))) {
 740                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 741                 rpc_exit(task, -EIO);
 742                 return;
 743         }
 744         if (encode == NULL)
 745                 return;
 746
 747         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 748                         task->tk_msg.rpc_argp);
 749         if (task->tk_status == -ENOMEM) {
 750                 /* XXX: Is this sane? */
 751                 rpc_delay(task, 3*HZ);
 752                 task->tk_status = -EAGAIN;
 753         }
 754 }
 755
 756 /*
 757  * 4.   Get the server port number if not yet set
 758  */
 759 static void
 760 call_bind(struct rpc_task *task)
 761 {
 762         struct rpc_clnt *clnt = task->tk_client;
 763
 764         dprintk("RPC: %4d call_bind (status %d)\n",
 765                                 task->tk_pid, task->tk_status);
 766
 767         task->tk_action = call_connect;
 768         if (!clnt->cl_port) {
 769                 task->tk_action = call_bind_status;
 770                 task->tk_timeout = task->tk_xprt->bind_timeout;
 771                 rpc_getport(task, clnt);
 772         }
 773 }
 774
 775 /*
 776  * 4a.  Sort out bind result
 777  */
 778 static void
 779 call_bind_status(struct rpc_task *task)
 780 {
 781         int status = -EACCES;
 782
 783         if (task->tk_status >= 0) {
 784                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 785                                         task->tk_pid, task->tk_status);
 786                 task->tk_status = 0;
 787                 task->tk_action = call_connect;
 788                 return;
 789         }
 790
 791         switch (task->tk_status) {
 792         case -EACCES:
 793                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 794                                 task->tk_pid);
 795                 rpc_delay(task, 3*HZ);
 796                 goto retry_bind;
 797         case -ETIMEDOUT:
 798                 dprintk("RPC: %4d rpcbind request timed out\n",
 799                                 task->tk_pid);
 800                 if (RPC_IS_SOFT(task)) {
 801                         status = -EIO;
 802                         break;
 803                 }
 804                 goto retry_bind;
 805         case -EPFNOSUPPORT:
 806                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 807                                 task->tk_pid);
 808                 break;
 809         case -EPROTONOSUPPORT:
 810                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 811                                 task->tk_pid);
 812                 break;
 813         default:
 814                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 815                                 task->tk_pid, -task->tk_status);
 816                 status = -EIO;
 817                 break;
 818         }
 819
 820         rpc_exit(task, status);
 821         return;
 822
 823 retry_bind:
 824         task->tk_status = 0;
 825         task->tk_action = call_bind;
 826         return;
 827 }
 828
 829 /*
 830  * 4b.  Connect to the RPC server
 831  */
 832 static void
 833 call_connect(struct rpc_task *task)
 834 {
 835         struct rpc_xprt *xprt = task->tk_xprt;
 836
 837         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 838                         task->tk_pid, xprt,
 839                         (xprt_connected(xprt) ? "is" : "is not"));
 840
 841         task->tk_action = call_transmit;
 842         if (!xprt_connected(xprt)) {
 843                 task->tk_action = call_connect_status;
 844                 if (task->tk_status < 0)
 845                         return;
 846                 xprt_connect(task);
 847         }
 848 }
 849
 850 /*
 851  * 4c.  Sort out connect result
 852  */
 853 static void
 854 call_connect_status(struct rpc_task *task)
 855 {
 856         struct rpc_clnt *clnt = task->tk_client;
 857         int status = task->tk_status;
 858
 859         dprintk("RPC: %5u call_connect_status (status %d)\n",
 860                                 task->tk_pid, task->tk_status);
 861
 862         task->tk_status = 0;
 863         if (status >= 0) {
 864                 clnt->cl_stats->netreconn++;
 865                 task->tk_action = call_transmit;
 866                 return;
 867         }
 868
 869         /* Something failed: remote service port may have changed */
 870         rpc_force_rebind(clnt);
 871
 872         switch (status) {
 873         case -ENOTCONN:
 874         case -ETIMEDOUT:
 875         case -EAGAIN:
 876                 task->tk_action = call_bind;
 877                 break;
 878         default:
 879                 rpc_exit(task, -EIO);
 880                 break;
 881         }
 882 }
 883
 884 /*
 885  * 5.   Transmit the RPC request, and wait for reply
 886  */
 887 static void
 888 call_transmit(struct rpc_task *task)
 889 {
 890         dprintk("RPC: %4d call_transmit (status %d)\n",
 891                                 task->tk_pid, task->tk_status);
 892
 893         task->tk_action = call_status;
 894         if (task->tk_status < 0)
 895                 return;
 896         task->tk_status = xprt_prepare_transmit(task);
 897         if (task->tk_status != 0)
 898                 return;
 899         /* Encode here so that rpcsec_gss can use correct sequence number. */
 900         if (rpc_task_need_encode(task)) {
 901                 task->tk_rqstp->rq_bytes_sent = 0;
 902                 call_encode(task);
 903                 /* Did the encode result in an error condition? */
 904                 if (task->tk_status != 0)
 905                         goto out_nosend;
 906         }
 907         task->tk_action = call_transmit_status;
 908         xprt_transmit(task);
 909         if (task->tk_status < 0)
 910                 return;
 911         if (!task->tk_msg.rpc_proc->p_decode) {
 912                 task->tk_action = rpc_exit_task;
 913                 rpc_wake_up_task(task);
 914         }
 915         return;
 916 out_nosend:
 917         /* release socket write lock before attempting to handle error */
 918         xprt_abort_transmit(task);
 919         rpc_task_force_reencode(task);
 920 }
 921
 922 /*
 923  * 6.   Sort out the RPC call status
 924  */
 925 static void
 926 call_status(struct rpc_task *task)
 927 {
 928         struct rpc_clnt *clnt = task->tk_client;
 929         struct rpc_rqst *req = task->tk_rqstp;
 930         int             status;
 931
 932         if (req->rq_received > 0 && !req->rq_bytes_sent)
 933                 task->tk_status = req->rq_received;
 934
 935         dprintk("RPC: %4d call_status (status %d)\n",
 936                                 task->tk_pid, task->tk_status);
 937
 938         status = task->tk_status;
 939         if (status >= 0) {
 940                 task->tk_action = call_decode;
 941                 return;
 942         }
 943
 944         task->tk_status = 0;
 945         switch(status) {
 946         case -ETIMEDOUT:
 947                 task->tk_action = call_timeout;
 948                 break;
 949         case -ECONNREFUSED:
 950         case -ENOTCONN:
 951                 rpc_force_rebind(clnt);
 952                 task->tk_action = call_bind;
 953                 break;
 954         case -EAGAIN:
 955                 task->tk_action = call_transmit;
 956                 break;
 957         case -EIO:
 958                 /* shutdown or soft timeout */
 959                 rpc_exit(task, status);
 960                 break;
 961         default:
 962                 printk("%s: RPC call returned error %d\n",
 963                                clnt->cl_protname, -status);
 964                 rpc_exit(task, status);
 965                 break;
 966         }
 967 }
 968
 969 /*
 970  * 6a.  Handle transmission errors.
 971  */
 972 static void
 973 call_transmit_status(struct rpc_task *task)
 974 {
 975         if (task->tk_status != -EAGAIN)
 976                 rpc_task_force_reencode(task);
 977         call_status(task);
 978 }
 979
 980 /*
 981  * 6b.  Handle RPC timeout
 982  *      We do not release the request slot, so we keep using the
 983  *      same XID for all retransmits.
 984  */
 985 static void
 986 call_timeout(struct rpc_task *task)
 987 {
 988         struct rpc_clnt *clnt = task->tk_client;
 989
 990         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
 991                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
 992                 goto retry;
 993         }
 994
 995         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
 996         if (RPC_IS_SOFT(task)) {
 997                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
 998                                 clnt->cl_protname, clnt->cl_server);
 999                 rpc_exit(task, -EIO);
1000                 return;
1001         }
1002
1003         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1004                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1005                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1006                         clnt->cl_protname, clnt->cl_server);
1007         }
1008         rpc_force_rebind(clnt);
1009
1010 retry:
1011         clnt->cl_stats->rpcretrans++;
1012         task->tk_action = call_bind;
1013         task->tk_status = 0;
1014 }
1015
1016 /*
1017  * 7.   Decode the RPC reply
1018  */
1019 static void
1020 call_decode(struct rpc_task *task)
1021 {
1022         struct rpc_clnt *clnt = task->tk_client;
1023         struct rpc_rqst *req = task->tk_rqstp;
1024         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1025         u32             *p;
1026
1027         dprintk("RPC: %4d call_decode (status %d)\n",
1028                                 task->tk_pid, task->tk_status);
1029
1030         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1031                 printk(KERN_NOTICE "%s: server %s OK\n",
1032                         clnt->cl_protname, clnt->cl_server);
1033                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1034         }
1035
1036         if (task->tk_status < 12) {
1037                 if (!RPC_IS_SOFT(task)) {
1038                         task->tk_action = call_bind;
1039                         clnt->cl_stats->rpcretrans++;
1040                         goto out_retry;
1041                 }
1042                 printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1043                         clnt->cl_protname, task->tk_status);
1044                 rpc_exit(task, -EIO);
1045                 return;
1046         }
1047
1048         req->rq_rcv_buf.len = req->rq_private_buf.len;
1049
1050         /* Check that the softirq receive buffer is valid */
1051         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1052                                 sizeof(req->rq_rcv_buf)) != 0);
1053
1054         /* Verify the RPC header */
1055         p = call_verify(task);
1056         if (IS_ERR(p)) {
1057                 if (p == ERR_PTR(-EAGAIN))
1058                         goto out_retry;
1059                 return;
1060         }
1061
1062         task->tk_action = rpc_exit_task;
1063
1064         if (decode)
1065                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1066                                                       task->tk_msg.rpc_resp);
1067         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1068                                         task->tk_status);
1069         return;
1070 out_retry:
1071         req->rq_received = req->rq_private_buf.len = 0;
1072         task->tk_status = 0;
1073 }
1074
1075 /*
1076  * 8.   Refresh the credentials if rejected by the server
1077  */
1078 static void
1079 call_refresh(struct rpc_task *task)
1080 {
1081         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1082
1083         xprt_release(task);     /* Must do to obtain new XID */
1084         task->tk_action = call_refreshresult;
1085         task->tk_status = 0;
1086         task->tk_client->cl_stats->rpcauthrefresh++;
1087         rpcauth_refreshcred(task);
1088 }
1089
1090 /*
1091  * 8a.  Process the results of a credential refresh
1092  */
1093 static void
1094 call_refreshresult(struct rpc_task *task)
1095 {
1096         int status = task->tk_status;
1097         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1098                                 task->tk_pid, task->tk_status);
1099
1100         task->tk_status = 0;
1101         task->tk_action = call_reserve;
1102         if (status >= 0 && rpcauth_uptodatecred(task))
1103                 return;
1104         if (status == -EACCES) {
1105                 rpc_exit(task, -EACCES);
1106                 return;
1107         }
1108         task->tk_action = call_refresh;
1109         if (status != -ETIMEDOUT)
1110                 rpc_delay(task, 3*HZ);
1111         return;
1112 }
1113
1114 /*
1115  * Call header serialization
1116  */
1117 static u32 *
1118 call_header(struct rpc_task *task)
1119 {
1120         struct rpc_clnt *clnt = task->tk_client;
1121         struct rpc_rqst *req = task->tk_rqstp;
1122         u32             *p = req->rq_svec[0].iov_base;
1123
1124         /* FIXME: check buffer size? */
1125
1126         p = xprt_skip_transport_header(task->tk_xprt, p);
1127         *p++ = req->rq_xid;             /* XID */
1128         *p++ = htonl(RPC_CALL);         /* CALL */
1129         *p++ = htonl(RPC_VERSION);      /* RPC version */
1130         *p++ = htonl(clnt->cl_prog);    /* program number */
1131         *p++ = htonl(clnt->cl_vers);    /* program version */
1132         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1133         p = rpcauth_marshcred(task, p);
1134         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1135         return p;
1136 }
1137
1138 /*
1139  * Reply header verification
1140  */
1141 static u32 *
1142 call_verify(struct rpc_task *task)
1143 {
1144         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1145         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1146         u32     *p = iov->iov_base, n;
1147         int error = -EACCES;
1148
1149         if ((len -= 3) < 0)
1150                 goto out_overflow;
1151         p += 1; /* skip XID */
1152
1153         if ((n = ntohl(*p++)) != RPC_REPLY) {
1154                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1155                 goto out_garbage;
1156         }
1157         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1158                 if (--len < 0)
1159                         goto out_overflow;
1160                 switch ((n = ntohl(*p++))) {
1161                         case RPC_AUTH_ERROR:
1162                                 break;
1163                         case RPC_MISMATCH:
1164                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1165                                 error = -EPROTONOSUPPORT;
1166                                 goto out_err;
1167                         default:
1168                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1169                                 goto out_eio;
1170                 }
1171                 if (--len < 0)
1172                         goto out_overflow;
1173                 switch ((n = ntohl(*p++))) {
1174                 case RPC_AUTH_REJECTEDCRED:
1175                 case RPC_AUTH_REJECTEDVERF:
1176                 case RPCSEC_GSS_CREDPROBLEM:
1177                 case RPCSEC_GSS_CTXPROBLEM:
1178                         if (!task->tk_cred_retry)
1179                                 break;
1180                         task->tk_cred_retry--;
1181                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1182                                                         task->tk_pid);
1183                         rpcauth_invalcred(task);
1184                         task->tk_action = call_refresh;
1185                         goto out_retry;
1186                 case RPC_AUTH_BADCRED:
1187                 case RPC_AUTH_BADVERF:
1188                         /* possibly garbled cred/verf? */
1189                         if (!task->tk_garb_retry)
1190                                 break;
1191                         task->tk_garb_retry--;
1192                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1193                                                         task->tk_pid);
1194                         task->tk_action = call_bind;
1195                         goto out_retry;
1196                 case RPC_AUTH_TOOWEAK:
1197                         printk(KERN_NOTICE "call_verify: server requires stronger "
1198                                "authentication.\n");
1199                         break;
1200                 default:
1201                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1202                         error = -EIO;
1203                 }
1204                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1205                                                 task->tk_pid, n);
1206                 goto out_err;
1207         }
1208         if (!(p = rpcauth_checkverf(task, p))) {
1209                 printk(KERN_WARNING "call_verify: auth check failed\n");
1210                 goto out_garbage;               /* bad verifier, retry */
1211         }
1212         len = p - (u32 *)iov->iov_base - 1;
1213         if (len < 0)
1214                 goto out_overflow;
1215         switch ((n = ntohl(*p++))) {
1216         case RPC_SUCCESS:
1217                 return p;
1218         case RPC_PROG_UNAVAIL:
1219                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1220                                 (unsigned int)task->tk_client->cl_prog,
1221                                 task->tk_client->cl_server);
1222                 error = -EPFNOSUPPORT;
1223                 goto out_err;
1224         case RPC_PROG_MISMATCH:
1225                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1226                                 (unsigned int)task->tk_client->cl_prog,
1227                                 (unsigned int)task->tk_client->cl_vers,
1228                                 task->tk_client->cl_server);
1229                 error = -EPROTONOSUPPORT;
1230                 goto out_err;
1231         case RPC_PROC_UNAVAIL:
1232                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1233                                 task->tk_msg.rpc_proc,
1234                                 task->tk_client->cl_prog,
1235                                 task->tk_client->cl_vers,
1236                                 task->tk_client->cl_server);
1237                 error = -EOPNOTSUPP;
1238                 goto out_err;
1239         case RPC_GARBAGE_ARGS:
1240                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1241                 break;                  /* retry */
1242         default:
1243                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1244                 /* Also retry */
1245         }
1246
1247 out_garbage:
1248         task->tk_client->cl_stats->rpcgarbage++;
1249         if (task->tk_garb_retry) {
1250                 task->tk_garb_retry--;
1251                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1252                 task->tk_action = call_bind;
1253 out_retry:
1254                 return ERR_PTR(-EAGAIN);
1255         }
1256         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1257 out_eio:
1258         error = -EIO;
1259 out_err:
1260         rpc_exit(task, error);
1261         return ERR_PTR(error);
1262 out_overflow:
1263         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1264         goto out_garbage;
1265 }
1266
1267 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1268 {
1269         return 0;
1270 }
1271
1272 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1273 {
1274         return 0;
1275 }
1276
1277 static struct rpc_procinfo rpcproc_null = {
1278         .p_encode = rpcproc_encode_null,
1279         .p_decode = rpcproc_decode_null,
1280 };
1281
1282 int rpc_ping(struct rpc_clnt *clnt, int flags)
1283 {
1284         struct rpc_message msg = {
1285                 .rpc_proc = &rpcproc_null,
1286         };
1287         int err;
1288         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1289         err = rpc_call_sync(clnt, &msg, flags);
1290         put_rpccred(msg.rpc_cred);
1291         return err;
1292 }