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  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  17  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  18  */
  19
  20
  21 #include <linux/module.h>
  22 #include <linux/types.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/mm.h>
  25 #include <linux/namei.h>
  26 #include <linux/mount.h>
  27 #include <linux/slab.h>
  28 #include <linux/rcupdate.h>
  29 #include <linux/utsname.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/in.h>
  32 #include <linux/in6.h>
  33 #include <linux/un.h>
  34
  35 #include <linux/sunrpc/clnt.h>
  36 #include <linux/sunrpc/addr.h>
  37 #include <linux/sunrpc/rpc_pipe_fs.h>
  38 #include <linux/sunrpc/metrics.h>
  39 #include <linux/sunrpc/bc_xprt.h>
  40 #include <trace/events/sunrpc.h>
  41
  42 #include "sunrpc.h"
  43 #include "netns.h"
  44
  45 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  46 # define RPCDBG_FACILITY        RPCDBG_CALL
  47 #endif
  48
  49 #define dprint_status(t)                                        \
  50         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  51                         __func__, t->tk_status)
  52
  53 /*
  54  * All RPC clients are linked into this list
  55  */
  56
  57 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  58
  59
  60 static void     call_start(struct rpc_task *task);
  61 static void     call_reserve(struct rpc_task *task);
  62 static void     call_reserveresult(struct rpc_task *task);
  63 static void     call_allocate(struct rpc_task *task);
  64 static void     call_decode(struct rpc_task *task);
  65 static void     call_bind(struct rpc_task *task);
  66 static void     call_bind_status(struct rpc_task *task);
  67 static void     call_transmit(struct rpc_task *task);
  68 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
  69 static void     call_bc_transmit(struct rpc_task *task);
  70 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
  71 static void     call_status(struct rpc_task *task);
  72 static void     call_transmit_status(struct rpc_task *task);
  73 static void     call_refresh(struct rpc_task *task);
  74 static void     call_refreshresult(struct rpc_task *task);
  75 static void     call_timeout(struct rpc_task *task);
  76 static void     call_connect(struct rpc_task *task);
  77 static void     call_connect_status(struct rpc_task *task);
  78
  79 static __be32   *rpc_encode_header(struct rpc_task *task);
  80 static __be32   *rpc_verify_header(struct rpc_task *task);
  81 static int      rpc_ping(struct rpc_clnt *clnt);
  82
  83 static void rpc_register_client(struct rpc_clnt *clnt)
  84 {
  85         struct net *net = rpc_net_ns(clnt);
  86         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
  87
  88         spin_lock(&sn->rpc_client_lock);
  89         list_add(&clnt->cl_clients, &sn->all_clients);
  90         spin_unlock(&sn->rpc_client_lock);
  91 }
  92
  93 static void rpc_unregister_client(struct rpc_clnt *clnt)
  94 {
  95         struct net *net = rpc_net_ns(clnt);
  96         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
  97
  98         spin_lock(&sn->rpc_client_lock);
  99         list_del(&clnt->cl_clients);
 100         spin_unlock(&sn->rpc_client_lock);
 101 }
 102
 103 static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
 104 {
 105         rpc_remove_client_dir(clnt);
 106 }
 107
 108 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
 109 {
 110         struct net *net = rpc_net_ns(clnt);
 111         struct super_block *pipefs_sb;
 112
 113         pipefs_sb = rpc_get_sb_net(net);
 114         if (pipefs_sb) {
 115                 __rpc_clnt_remove_pipedir(clnt);
 116                 rpc_put_sb_net(net);
 117         }
 118 }
 119
 120 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
 121                                     struct rpc_clnt *clnt)
 122 {
 123         static uint32_t clntid;
 124         const char *dir_name = clnt->cl_program->pipe_dir_name;
 125         char name[15];
 126         struct dentry *dir, *dentry;
 127
 128         dir = rpc_d_lookup_sb(sb, dir_name);
 129         if (dir == NULL) {
 130                 pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name);
 131                 return dir;
 132         }
 133         for (;;) {
 134                 snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
 135                 name[sizeof(name) - 1] = '\0';
 136                 dentry = rpc_create_client_dir(dir, name, clnt);
 137                 if (!IS_ERR(dentry))
 138                         break;
 139                 if (dentry == ERR_PTR(-EEXIST))
 140                         continue;
 141                 printk(KERN_INFO "RPC: Couldn't create pipefs entry"
 142                                 " %s/%s, error %ld\n",
 143                                 dir_name, name, PTR_ERR(dentry));
 144                 break;
 145         }
 146         dput(dir);
 147         return dentry;
 148 }
 149
 150 static int
 151 rpc_setup_pipedir(struct super_block *pipefs_sb, struct rpc_clnt *clnt)
 152 {
 153         struct dentry *dentry;
 154
 155         if (clnt->cl_program->pipe_dir_name != NULL) {
 156                 dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt);
 157                 if (IS_ERR(dentry))
 158                         return PTR_ERR(dentry);
 159         }
 160         return 0;
 161 }
 162
 163 static int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event)
 164 {
 165         if (clnt->cl_program->pipe_dir_name == NULL)
 166                 return 1;
 167
 168         switch (event) {
 169         case RPC_PIPEFS_MOUNT:
 170                 if (clnt->cl_pipedir_objects.pdh_dentry != NULL)
 171                         return 1;
 172                 if (atomic_read(&clnt->cl_count) == 0)
 173                         return 1;
 174                 break;
 175         case RPC_PIPEFS_UMOUNT:
 176                 if (clnt->cl_pipedir_objects.pdh_dentry == NULL)
 177                         return 1;
 178                 break;
 179         }
 180         return 0;
 181 }
 182
 183 static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event,
 184                                    struct super_block *sb)
 185 {
 186         struct dentry *dentry;
 187         int err = 0;
 188
 189         switch (event) {
 190         case RPC_PIPEFS_MOUNT:
 191                 dentry = rpc_setup_pipedir_sb(sb, clnt);
 192                 if (!dentry)
 193                         return -ENOENT;
 194                 if (IS_ERR(dentry))
 195                         return PTR_ERR(dentry);
 196                 break;
 197         case RPC_PIPEFS_UMOUNT:
 198                 __rpc_clnt_remove_pipedir(clnt);
 199                 break;
 200         default:
 201                 printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event);
 202                 return -ENOTSUPP;
 203         }
 204         return err;
 205 }
 206
 207 static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,
 208                                 struct super_block *sb)
 209 {
 210         int error = 0;
 211
 212         for (;; clnt = clnt->cl_parent) {
 213                 if (!rpc_clnt_skip_event(clnt, event))
 214                         error = __rpc_clnt_handle_event(clnt, event, sb);
 215                 if (error || clnt == clnt->cl_parent)
 216                         break;
 217         }
 218         return error;
 219 }
 220
 221 static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
 222 {
 223         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 224         struct rpc_clnt *clnt;
 225
 226         spin_lock(&sn->rpc_client_lock);
 227         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
 228                 if (rpc_clnt_skip_event(clnt, event))
 229                         continue;
 230                 spin_unlock(&sn->rpc_client_lock);
 231                 return clnt;
 232         }
 233         spin_unlock(&sn->rpc_client_lock);
 234         return NULL;
 235 }
 236
 237 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 238                             void *ptr)
 239 {
 240         struct super_block *sb = ptr;
 241         struct rpc_clnt *clnt;
 242         int error = 0;
 243
 244         while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
 245                 error = __rpc_pipefs_event(clnt, event, sb);
 246                 if (error)
 247                         break;
 248         }
 249         return error;
 250 }
 251
 252 static struct notifier_block rpc_clients_block = {
 253         .notifier_call  = rpc_pipefs_event,
 254         .priority       = SUNRPC_PIPEFS_RPC_PRIO,
 255 };
 256
 257 int rpc_clients_notifier_register(void)
 258 {
 259         return rpc_pipefs_notifier_register(&rpc_clients_block);
 260 }
 261
 262 void rpc_clients_notifier_unregister(void)
 263 {
 264         return rpc_pipefs_notifier_unregister(&rpc_clients_block);
 265 }
 266
 267 static struct rpc_xprt *rpc_clnt_set_transport(struct rpc_clnt *clnt,
 268                 struct rpc_xprt *xprt,
 269                 const struct rpc_timeout *timeout)
 270 {
 271         struct rpc_xprt *old;
 272
 273         spin_lock(&clnt->cl_lock);
 274         old = rcu_dereference_protected(clnt->cl_xprt,
 275                         lockdep_is_held(&clnt->cl_lock));
 276
 277         if (!xprt_bound(xprt))
 278                 clnt->cl_autobind = 1;
 279
 280         clnt->cl_timeout = timeout;
 281         rcu_assign_pointer(clnt->cl_xprt, xprt);
 282         spin_unlock(&clnt->cl_lock);
 283
 284         return old;
 285 }
 286
 287 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
 288 {
 289         clnt->cl_nodelen = strlcpy(clnt->cl_nodename,
 290                         nodename, sizeof(clnt->cl_nodename));
 291 }
 292
 293 static int rpc_client_register(struct rpc_clnt *clnt,
 294                                rpc_authflavor_t pseudoflavor,
 295                                const char *client_name)
 296 {
 297         struct rpc_auth_create_args auth_args = {
 298                 .pseudoflavor = pseudoflavor,
 299                 .target_name = client_name,
 300         };
 301         struct rpc_auth *auth;
 302         struct net *net = rpc_net_ns(clnt);
 303         struct super_block *pipefs_sb;
 304         int err;
 305
 306         rpc_clnt_debugfs_register(clnt);
 307
 308         pipefs_sb = rpc_get_sb_net(net);
 309         if (pipefs_sb) {
 310                 err = rpc_setup_pipedir(pipefs_sb, clnt);
 311                 if (err)
 312                         goto out;
 313         }
 314
 315         rpc_register_client(clnt);
 316         if (pipefs_sb)
 317                 rpc_put_sb_net(net);
 318
 319         auth = rpcauth_create(&auth_args, clnt);
 320         if (IS_ERR(auth)) {
 321                 dprintk("RPC:       Couldn't create auth handle (flavor %u)\n",
 322                                 pseudoflavor);
 323                 err = PTR_ERR(auth);
 324                 goto err_auth;
 325         }
 326         return 0;
 327 err_auth:
 328         pipefs_sb = rpc_get_sb_net(net);
 329         rpc_unregister_client(clnt);
 330         __rpc_clnt_remove_pipedir(clnt);
 331 out:
 332         if (pipefs_sb)
 333                 rpc_put_sb_net(net);
 334         rpc_clnt_debugfs_unregister(clnt);
 335         return err;
 336 }
 337
 338 static DEFINE_IDA(rpc_clids);
 339
 340 static int rpc_alloc_clid(struct rpc_clnt *clnt)
 341 {
 342         int clid;
 343
 344         clid = ida_simple_get(&rpc_clids, 0, 0, GFP_KERNEL);
 345         if (clid < 0)
 346                 return clid;
 347         clnt->cl_clid = clid;
 348         return 0;
 349 }
 350
 351 static void rpc_free_clid(struct rpc_clnt *clnt)
 352 {
 353         ida_simple_remove(&rpc_clids, clnt->cl_clid);
 354 }
 355
 356 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
 357                 struct rpc_xprt *xprt,
 358                 struct rpc_clnt *parent)
 359 {
 360         const struct rpc_program *program = args->program;
 361         const struct rpc_version *version;
 362         struct rpc_clnt *clnt = NULL;
 363         const struct rpc_timeout *timeout;
 364         const char *nodename = args->nodename;
 365         int err;
 366
 367         /* sanity check the name before trying to print it */
 368         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 369                         program->name, args->servername, xprt);
 370
 371         err = rpciod_up();
 372         if (err)
 373                 goto out_no_rpciod;
 374
 375         err = -EINVAL;
 376         if (args->version >= program->nrvers)
 377                 goto out_err;
 378         version = program->version[args->version];
 379         if (version == NULL)
 380                 goto out_err;
 381
 382         err = -ENOMEM;
 383         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 384         if (!clnt)
 385                 goto out_err;
 386         clnt->cl_parent = parent ? : clnt;
 387
 388         err = rpc_alloc_clid(clnt);
 389         if (err)
 390                 goto out_no_clid;
 391
 392         clnt->cl_procinfo = version->procs;
 393         clnt->cl_maxproc  = version->nrprocs;
 394         clnt->cl_prog     = args->prognumber ? : program->number;
 395         clnt->cl_vers     = version->number;
 396         clnt->cl_stats    = program->stats;
 397         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 398         rpc_init_pipe_dir_head(&clnt->cl_pipedir_objects);
 399         err = -ENOMEM;
 400         if (clnt->cl_metrics == NULL)
 401                 goto out_no_stats;
 402         clnt->cl_program  = program;
 403         INIT_LIST_HEAD(&clnt->cl_tasks);
 404         spin_lock_init(&clnt->cl_lock);
 405
 406         timeout = xprt->timeout;
 407         if (args->timeout != NULL) {
 408                 memcpy(&clnt->cl_timeout_default, args->timeout,
 409                                 sizeof(clnt->cl_timeout_default));
 410                 timeout = &clnt->cl_timeout_default;
 411         }
 412
 413         rpc_clnt_set_transport(clnt, xprt, timeout);
 414
 415         clnt->cl_rtt = &clnt->cl_rtt_default;
 416         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 417
 418         atomic_set(&clnt->cl_count, 1);
 419
 420         if (nodename == NULL)
 421                 nodename = utsname()->nodename;
 422         /* save the nodename */
 423         rpc_clnt_set_nodename(clnt, nodename);
 424
 425         err = rpc_client_register(clnt, args->authflavor, args->client_name);
 426         if (err)
 427                 goto out_no_path;
 428         if (parent)
 429                 atomic_inc(&parent->cl_count);
 430         return clnt;
 431
 432 out_no_path:
 433         rpc_free_iostats(clnt->cl_metrics);
 434 out_no_stats:
 435         rpc_free_clid(clnt);
 436 out_no_clid:
 437         kfree(clnt);
 438 out_err:
 439         rpciod_down();
 440 out_no_rpciod:
 441         xprt_put(xprt);
 442         return ERR_PTR(err);
 443 }
 444
 445 struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args,
 446                                         struct rpc_xprt *xprt)
 447 {
 448         struct rpc_clnt *clnt = NULL;
 449
 450         clnt = rpc_new_client(args, xprt, NULL);
 451         if (IS_ERR(clnt))
 452                 return clnt;
 453
 454         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 455                 int err = rpc_ping(clnt);
 456                 if (err != 0) {
 457                         rpc_shutdown_client(clnt);
 458                         return ERR_PTR(err);
 459                 }
 460         }
 461
 462         clnt->cl_softrtry = 1;
 463         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 464                 clnt->cl_softrtry = 0;
 465
 466         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 467                 clnt->cl_autobind = 1;
 468         if (args->flags & RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT)
 469                 clnt->cl_noretranstimeo = 1;
 470         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 471                 clnt->cl_discrtry = 1;
 472         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 473                 clnt->cl_chatty = 1;
 474
 475         return clnt;
 476 }
 477 EXPORT_SYMBOL_GPL(rpc_create_xprt);
 478
 479 /**
 480  * rpc_create - create an RPC client and transport with one call
 481  * @args: rpc_clnt create argument structure
 482  *
 483  * Creates and initializes an RPC transport and an RPC client.
 484  *
 485  * It can ping the server in order to determine if it is up, and to see if
 486  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 487  * this behavior so asynchronous tasks can also use rpc_create.
 488  */
 489 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 490 {
 491         struct rpc_xprt *xprt;
 492         struct xprt_create xprtargs = {
 493                 .net = args->net,
 494                 .ident = args->protocol,
 495                 .srcaddr = args->saddress,
 496                 .dstaddr = args->address,
 497                 .addrlen = args->addrsize,
 498                 .servername = args->servername,
 499                 .bc_xprt = args->bc_xprt,
 500         };
 501         char servername[48];
 502
 503         if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
 504                 xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
 505         if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
 506                 xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
 507         /*
 508          * If the caller chooses not to specify a hostname, whip
 509          * up a string representation of the passed-in address.
 510          */
 511         if (xprtargs.servername == NULL) {
 512                 struct sockaddr_un *sun =
 513                                 (struct sockaddr_un *)args->address;
 514                 struct sockaddr_in *sin =
 515                                 (struct sockaddr_in *)args->address;
 516                 struct sockaddr_in6 *sin6 =
 517                                 (struct sockaddr_in6 *)args->address;
 518
 519                 servername[0] = '\0';
 520                 switch (args->address->sa_family) {
 521                 case AF_LOCAL:
 522                         snprintf(servername, sizeof(servername), "%s",
 523                                  sun->sun_path);
 524                         break;
 525                 case AF_INET:
 526                         snprintf(servername, sizeof(servername), "%pI4",
 527                                  &sin->sin_addr.s_addr);
 528                         break;
 529                 case AF_INET6:
 530                         snprintf(servername, sizeof(servername), "%pI6",
 531                                  &sin6->sin6_addr);
 532                         break;
 533                 default:
 534                         /* caller wants default server name, but
 535                          * address family isn't recognized. */
 536                         return ERR_PTR(-EINVAL);
 537                 }
 538                 xprtargs.servername = servername;
 539         }
 540
 541         xprt = xprt_create_transport(&xprtargs);
 542         if (IS_ERR(xprt))
 543                 return (struct rpc_clnt *)xprt;
 544
 545         /*
 546          * By default, kernel RPC client connects from a reserved port.
 547          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 548          * but it is always enabled for rpciod, which handles the connect
 549          * operation.
 550          */
 551         xprt->resvport = 1;
 552         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 553                 xprt->resvport = 0;
 554
 555         return rpc_create_xprt(args, xprt);
 556 }
 557 EXPORT_SYMBOL_GPL(rpc_create);
 558
 559 /*
 560  * This function clones the RPC client structure. It allows us to share the
 561  * same transport while varying parameters such as the authentication
 562  * flavour.
 563  */
 564 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
 565                                            struct rpc_clnt *clnt)
 566 {
 567         struct rpc_xprt *xprt;
 568         struct rpc_clnt *new;
 569         int err;
 570
 571         err = -ENOMEM;
 572         rcu_read_lock();
 573         xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
 574         rcu_read_unlock();
 575         if (xprt == NULL)
 576                 goto out_err;
 577         args->servername = xprt->servername;
 578         args->nodename = clnt->cl_nodename;
 579
 580         new = rpc_new_client(args, xprt, clnt);
 581         if (IS_ERR(new)) {
 582                 err = PTR_ERR(new);
 583                 goto out_err;
 584         }
 585
 586         /* Turn off autobind on clones */
 587         new->cl_autobind = 0;
 588         new->cl_softrtry = clnt->cl_softrtry;
 589         new->cl_noretranstimeo = clnt->cl_noretranstimeo;
 590         new->cl_discrtry = clnt->cl_discrtry;
 591         new->cl_chatty = clnt->cl_chatty;
 592         return new;
 593
 594 out_err:
 595         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 596         return ERR_PTR(err);
 597 }
 598
 599 /**
 600  * rpc_clone_client - Clone an RPC client structure
 601  *
 602  * @clnt: RPC client whose parameters are copied
 603  *
 604  * Returns a fresh RPC client or an ERR_PTR.
 605  */
 606 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
 607 {
 608         struct rpc_create_args args = {
 609                 .program        = clnt->cl_program,
 610                 .prognumber     = clnt->cl_prog,
 611                 .version        = clnt->cl_vers,
 612                 .authflavor     = clnt->cl_auth->au_flavor,
 613         };
 614         return __rpc_clone_client(&args, clnt);
 615 }
 616 EXPORT_SYMBOL_GPL(rpc_clone_client);
 617
 618 /**
 619  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
 620  *
 621  * @clnt: RPC client whose parameters are copied
 622  * @flavor: security flavor for new client
 623  *
 624  * Returns a fresh RPC client or an ERR_PTR.
 625  */
 626 struct rpc_clnt *
 627 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 628 {
 629         struct rpc_create_args args = {
 630                 .program        = clnt->cl_program,
 631                 .prognumber     = clnt->cl_prog,
 632                 .version        = clnt->cl_vers,
 633                 .authflavor     = flavor,
 634         };
 635         return __rpc_clone_client(&args, clnt);
 636 }
 637 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
 638
 639 /**
 640  * rpc_switch_client_transport: switch the RPC transport on the fly
 641  * @clnt: pointer to a struct rpc_clnt
 642  * @args: pointer to the new transport arguments
 643  * @timeout: pointer to the new timeout parameters
 644  *
 645  * This function allows the caller to switch the RPC transport for the
 646  * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS
 647  * server, for instance.  It assumes that the caller has ensured that
 648  * there are no active RPC tasks by using some form of locking.
 649  *
 650  * Returns zero if "clnt" is now using the new xprt.  Otherwise a
 651  * negative errno is returned, and "clnt" continues to use the old
 652  * xprt.
 653  */
 654 int rpc_switch_client_transport(struct rpc_clnt *clnt,
 655                 struct xprt_create *args,
 656                 const struct rpc_timeout *timeout)
 657 {
 658         const struct rpc_timeout *old_timeo;
 659         rpc_authflavor_t pseudoflavor;
 660         struct rpc_xprt *xprt, *old;
 661         struct rpc_clnt *parent;
 662         int err;
 663
 664         xprt = xprt_create_transport(args);
 665         if (IS_ERR(xprt)) {
 666                 dprintk("RPC:       failed to create new xprt for clnt %p\n",
 667                         clnt);
 668                 return PTR_ERR(xprt);
 669         }
 670
 671         pseudoflavor = clnt->cl_auth->au_flavor;
 672
 673         old_timeo = clnt->cl_timeout;
 674         old = rpc_clnt_set_transport(clnt, xprt, timeout);
 675
 676         rpc_unregister_client(clnt);
 677         __rpc_clnt_remove_pipedir(clnt);
 678         rpc_clnt_debugfs_unregister(clnt);
 679
 680         /*
 681          * A new transport was created.  "clnt" therefore
 682          * becomes the root of a new cl_parent tree.  clnt's
 683          * children, if it has any, still point to the old xprt.
 684          */
 685         parent = clnt->cl_parent;
 686         clnt->cl_parent = clnt;
 687
 688         /*
 689          * The old rpc_auth cache cannot be re-used.  GSS
 690          * contexts in particular are between a single
 691          * client and server.
 692          */
 693         err = rpc_client_register(clnt, pseudoflavor, NULL);
 694         if (err)
 695                 goto out_revert;
 696
 697         synchronize_rcu();
 698         if (parent != clnt)
 699                 rpc_release_client(parent);
 700         xprt_put(old);
 701         dprintk("RPC:       replaced xprt for clnt %p\n", clnt);
 702         return 0;
 703
 704 out_revert:
 705         rpc_clnt_set_transport(clnt, old, old_timeo);
 706         clnt->cl_parent = parent;
 707         rpc_client_register(clnt, pseudoflavor, NULL);
 708         xprt_put(xprt);
 709         dprintk("RPC:       failed to switch xprt for clnt %p\n", clnt);
 710         return err;
 711 }
 712 EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
 713
 714 /*
 715  * Kill all tasks for the given client.
 716  * XXX: kill their descendants as well?
 717  */
 718 void rpc_killall_tasks(struct rpc_clnt *clnt)
 719 {
 720         struct rpc_task *rovr;
 721
 722
 723         if (list_empty(&clnt->cl_tasks))
 724                 return;
 725         dprintk("RPC:       killing all tasks for client %p\n", clnt);
 726         /*
 727          * Spin lock all_tasks to prevent changes...
 728          */
 729         spin_lock(&clnt->cl_lock);
 730         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
 731                 if (!RPC_IS_ACTIVATED(rovr))
 732                         continue;
 733                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
 734                         rovr->tk_flags |= RPC_TASK_KILLED;
 735                         rpc_exit(rovr, -EIO);
 736                         if (RPC_IS_QUEUED(rovr))
 737                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
 738                                                         rovr);
 739                 }
 740         }
 741         spin_unlock(&clnt->cl_lock);
 742 }
 743 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 744
 745 /*
 746  * Properly shut down an RPC client, terminating all outstanding
 747  * requests.
 748  */
 749 void rpc_shutdown_client(struct rpc_clnt *clnt)
 750 {
 751         might_sleep();
 752
 753         dprintk_rcu("RPC:       shutting down %s client for %s\n",
 754                         clnt->cl_program->name,
 755                         rcu_dereference(clnt->cl_xprt)->servername);
 756
 757         while (!list_empty(&clnt->cl_tasks)) {
 758                 rpc_killall_tasks(clnt);
 759                 wait_event_timeout(destroy_wait,
 760                         list_empty(&clnt->cl_tasks), 1*HZ);
 761         }
 762
 763         rpc_release_client(clnt);
 764 }
 765 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 766
 767 /*
 768  * Free an RPC client
 769  */
 770 static struct rpc_clnt *
 771 rpc_free_client(struct rpc_clnt *clnt)
 772 {
 773         struct rpc_clnt *parent = NULL;
 774
 775         dprintk_rcu("RPC:       destroying %s client for %s\n",
 776                         clnt->cl_program->name,
 777                         rcu_dereference(clnt->cl_xprt)->servername);
 778         if (clnt->cl_parent != clnt)
 779                 parent = clnt->cl_parent;
 780         rpc_clnt_debugfs_unregister(clnt);
 781         rpc_clnt_remove_pipedir(clnt);
 782         rpc_unregister_client(clnt);
 783         rpc_free_iostats(clnt->cl_metrics);
 784         clnt->cl_metrics = NULL;
 785         xprt_put(rcu_dereference_raw(clnt->cl_xprt));
 786         rpciod_down();
 787         rpc_free_clid(clnt);
 788         kfree(clnt);
 789         return parent;
 790 }
 791
 792 /*
 793  * Free an RPC client
 794  */
 795 static struct rpc_clnt *
 796 rpc_free_auth(struct rpc_clnt *clnt)
 797 {
 798         if (clnt->cl_auth == NULL)
 799                 return rpc_free_client(clnt);
 800
 801         /*
 802          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 803          *       release remaining GSS contexts. This mechanism ensures
 804          *       that it can do so safely.
 805          */
 806         atomic_inc(&clnt->cl_count);
 807         rpcauth_release(clnt->cl_auth);
 808         clnt->cl_auth = NULL;
 809         if (atomic_dec_and_test(&clnt->cl_count))
 810                 return rpc_free_client(clnt);
 811         return NULL;
 812 }
 813
 814 /*
 815  * Release reference to the RPC client
 816  */
 817 void
 818 rpc_release_client(struct rpc_clnt *clnt)
 819 {
 820         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 821
 822         do {
 823                 if (list_empty(&clnt->cl_tasks))
 824                         wake_up(&destroy_wait);
 825                 if (!atomic_dec_and_test(&clnt->cl_count))
 826                         break;
 827                 clnt = rpc_free_auth(clnt);
 828         } while (clnt != NULL);
 829 }
 830 EXPORT_SYMBOL_GPL(rpc_release_client);
 831
 832 /**
 833  * rpc_bind_new_program - bind a new RPC program to an existing client
 834  * @old: old rpc_client
 835  * @program: rpc program to set
 836  * @vers: rpc program version
 837  *
 838  * Clones the rpc client and sets up a new RPC program. This is mainly
 839  * of use for enabling different RPC programs to share the same transport.
 840  * The Sun NFSv2/v3 ACL protocol can do this.
 841  */
 842 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 843                                       const struct rpc_program *program,
 844                                       u32 vers)
 845 {
 846         struct rpc_create_args args = {
 847                 .program        = program,
 848                 .prognumber     = program->number,
 849                 .version        = vers,
 850                 .authflavor     = old->cl_auth->au_flavor,
 851         };
 852         struct rpc_clnt *clnt;
 853         int err;
 854
 855         clnt = __rpc_clone_client(&args, old);
 856         if (IS_ERR(clnt))
 857                 goto out;
 858         err = rpc_ping(clnt);
 859         if (err != 0) {
 860                 rpc_shutdown_client(clnt);
 861                 clnt = ERR_PTR(err);
 862         }
 863 out:
 864         return clnt;
 865 }
 866 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 867
 868 void rpc_task_release_client(struct rpc_task *task)
 869 {
 870         struct rpc_clnt *clnt = task->tk_client;
 871
 872         if (clnt != NULL) {
 873                 /* Remove from client task list */
 874                 spin_lock(&clnt->cl_lock);
 875                 list_del(&task->tk_task);
 876                 spin_unlock(&clnt->cl_lock);
 877                 task->tk_client = NULL;
 878
 879                 rpc_release_client(clnt);
 880         }
 881 }
 882
 883 static
 884 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 885 {
 886         if (clnt != NULL) {
 887                 rpc_task_release_client(task);
 888                 task->tk_client = clnt;
 889                 atomic_inc(&clnt->cl_count);
 890                 if (clnt->cl_softrtry)
 891                         task->tk_flags |= RPC_TASK_SOFT;
 892                 if (clnt->cl_noretranstimeo)
 893                         task->tk_flags |= RPC_TASK_NO_RETRANS_TIMEOUT;
 894                 if (sk_memalloc_socks()) {
 895                         struct rpc_xprt *xprt;
 896
 897                         rcu_read_lock();
 898                         xprt = rcu_dereference(clnt->cl_xprt);
 899                         if (xprt->swapper)
 900                                 task->tk_flags |= RPC_TASK_SWAPPER;
 901                         rcu_read_unlock();
 902                 }
 903                 /* Add to the client's list of all tasks */
 904                 spin_lock(&clnt->cl_lock);
 905                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 906                 spin_unlock(&clnt->cl_lock);
 907         }
 908 }
 909
 910 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 911 {
 912         rpc_task_release_client(task);
 913         rpc_task_set_client(task, clnt);
 914 }
 915 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 916
 917
 918 static void
 919 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 920 {
 921         if (msg != NULL) {
 922                 task->tk_msg.rpc_proc = msg->rpc_proc;
 923                 task->tk_msg.rpc_argp = msg->rpc_argp;
 924                 task->tk_msg.rpc_resp = msg->rpc_resp;
 925                 if (msg->rpc_cred != NULL)
 926                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 927         }
 928 }
 929
 930 /*
 931  * Default callback for async RPC calls
 932  */
 933 static void
 934 rpc_default_callback(struct rpc_task *task, void *data)
 935 {
 936 }
 937
 938 static const struct rpc_call_ops rpc_default_ops = {
 939         .rpc_call_done = rpc_default_callback,
 940 };
 941
 942 /**
 943  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 944  * @task_setup_data: pointer to task initialisation data
 945  */
 946 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 947 {
 948         struct rpc_task *task;
 949
 950         task = rpc_new_task(task_setup_data);
 951         if (IS_ERR(task))
 952                 goto out;
 953
 954         rpc_task_set_client(task, task_setup_data->rpc_client);
 955         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 956
 957         if (task->tk_action == NULL)
 958                 rpc_call_start(task);
 959
 960         atomic_inc(&task->tk_count);
 961         rpc_execute(task);
 962 out:
 963         return task;
 964 }
 965 EXPORT_SYMBOL_GPL(rpc_run_task);
 966
 967 /**
 968  * rpc_call_sync - Perform a synchronous RPC call
 969  * @clnt: pointer to RPC client
 970  * @msg: RPC call parameters
 971  * @flags: RPC call flags
 972  */
 973 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 974 {
 975         struct rpc_task *task;
 976         struct rpc_task_setup task_setup_data = {
 977                 .rpc_client = clnt,
 978                 .rpc_message = msg,
 979                 .callback_ops = &rpc_default_ops,
 980                 .flags = flags,
 981         };
 982         int status;
 983
 984         WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
 985         if (flags & RPC_TASK_ASYNC) {
 986                 rpc_release_calldata(task_setup_data.callback_ops,
 987                         task_setup_data.callback_data);
 988                 return -EINVAL;
 989         }
 990
 991         task = rpc_run_task(&task_setup_data);
 992         if (IS_ERR(task))
 993                 return PTR_ERR(task);
 994         status = task->tk_status;
 995         rpc_put_task(task);
 996         return status;
 997 }
 998 EXPORT_SYMBOL_GPL(rpc_call_sync);
 999
1000 /**
1001  * rpc_call_async - Perform an asynchronous RPC call
1002  * @clnt: pointer to RPC client
1003  * @msg: RPC call parameters
1004  * @flags: RPC call flags
1005  * @tk_ops: RPC call ops
1006  * @data: user call data
1007  */
1008 int
1009 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
1010                const struct rpc_call_ops *tk_ops, void *data)
1011 {
1012         struct rpc_task *task;
1013         struct rpc_task_setup task_setup_data = {
1014                 .rpc_client = clnt,
1015                 .rpc_message = msg,
1016                 .callback_ops = tk_ops,
1017                 .callback_data = data,
1018                 .flags = flags|RPC_TASK_ASYNC,
1019         };
1020
1021         task = rpc_run_task(&task_setup_data);
1022         if (IS_ERR(task))
1023                 return PTR_ERR(task);
1024         rpc_put_task(task);
1025         return 0;
1026 }
1027 EXPORT_SYMBOL_GPL(rpc_call_async);
1028
1029 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1030 /**
1031  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1032  * rpc_execute against it
1033  * @req: RPC request
1034  */
1035 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req)
1036 {
1037         struct rpc_task *task;
1038         struct xdr_buf *xbufp = &req->rq_snd_buf;
1039         struct rpc_task_setup task_setup_data = {
1040                 .callback_ops = &rpc_default_ops,
1041         };
1042
1043         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
1044         /*
1045          * Create an rpc_task to send the data
1046          */
1047         task = rpc_new_task(&task_setup_data);
1048         if (IS_ERR(task)) {
1049                 xprt_free_bc_request(req);
1050                 goto out;
1051         }
1052         task->tk_rqstp = req;
1053
1054         /*
1055          * Set up the xdr_buf length.
1056          * This also indicates that the buffer is XDR encoded already.
1057          */
1058         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
1059                         xbufp->tail[0].iov_len;
1060
1061         task->tk_action = call_bc_transmit;
1062         atomic_inc(&task->tk_count);
1063         WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
1064         rpc_execute(task);
1065
1066 out:
1067         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
1068         return task;
1069 }
1070 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1071
1072 void
1073 rpc_call_start(struct rpc_task *task)
1074 {
1075         task->tk_action = call_start;
1076 }
1077 EXPORT_SYMBOL_GPL(rpc_call_start);
1078
1079 /**
1080  * rpc_peeraddr - extract remote peer address from clnt's xprt
1081  * @clnt: RPC client structure
1082  * @buf: target buffer
1083  * @bufsize: length of target buffer
1084  *
1085  * Returns the number of bytes that are actually in the stored address.
1086  */
1087 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
1088 {
1089         size_t bytes;
1090         struct rpc_xprt *xprt;
1091
1092         rcu_read_lock();
1093         xprt = rcu_dereference(clnt->cl_xprt);
1094
1095         bytes = xprt->addrlen;
1096         if (bytes > bufsize)
1097                 bytes = bufsize;
1098         memcpy(buf, &xprt->addr, bytes);
1099         rcu_read_unlock();
1100
1101         return bytes;
1102 }
1103 EXPORT_SYMBOL_GPL(rpc_peeraddr);
1104
1105 /**
1106  * rpc_peeraddr2str - return remote peer address in printable format
1107  * @clnt: RPC client structure
1108  * @format: address format
1109  *
1110  * NB: the lifetime of the memory referenced by the returned pointer is
1111  * the same as the rpc_xprt itself.  As long as the caller uses this
1112  * pointer, it must hold the RCU read lock.
1113  */
1114 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
1115                              enum rpc_display_format_t format)
1116 {
1117         struct rpc_xprt *xprt;
1118
1119         xprt = rcu_dereference(clnt->cl_xprt);
1120
1121         if (xprt->address_strings[format] != NULL)
1122                 return xprt->address_strings[format];
1123         else
1124                 return "unprintable";
1125 }
1126 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
1127
1128 static const struct sockaddr_in rpc_inaddr_loopback = {
1129         .sin_family             = AF_INET,
1130         .sin_addr.s_addr        = htonl(INADDR_ANY),
1131 };
1132
1133 static const struct sockaddr_in6 rpc_in6addr_loopback = {
1134         .sin6_family            = AF_INET6,
1135         .sin6_addr              = IN6ADDR_ANY_INIT,
1136 };
1137
1138 /*
1139  * Try a getsockname() on a connected datagram socket.  Using a
1140  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1141  * This conserves the ephemeral port number space.
1142  *
1143  * Returns zero and fills in "buf" if successful; otherwise, a
1144  * negative errno is returned.
1145  */
1146 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1147                         struct sockaddr *buf, int buflen)
1148 {
1149         struct socket *sock;
1150         int err;
1151
1152         err = __sock_create(net, sap->sa_family,
1153                                 SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1154         if (err < 0) {
1155                 dprintk("RPC:       can't create UDP socket (%d)\n", err);
1156                 goto out;
1157         }
1158
1159         switch (sap->sa_family) {
1160         case AF_INET:
1161                 err = kernel_bind(sock,
1162                                 (struct sockaddr *)&rpc_inaddr_loopback,
1163                                 sizeof(rpc_inaddr_loopback));
1164                 break;
1165         case AF_INET6:
1166                 err = kernel_bind(sock,
1167                                 (struct sockaddr *)&rpc_in6addr_loopback,
1168                                 sizeof(rpc_in6addr_loopback));
1169                 break;
1170         default:
1171                 err = -EAFNOSUPPORT;
1172                 goto out;
1173         }
1174         if (err < 0) {
1175                 dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1176                 goto out_release;
1177         }
1178
1179         err = kernel_connect(sock, sap, salen, 0);
1180         if (err < 0) {
1181                 dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1182                 goto out_release;
1183         }
1184
1185         err = kernel_getsockname(sock, buf, &buflen);
1186         if (err < 0) {
1187                 dprintk("RPC:       getsockname failed (%d)\n", err);
1188                 goto out_release;
1189         }
1190
1191         err = 0;
1192         if (buf->sa_family == AF_INET6) {
1193                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1194                 sin6->sin6_scope_id = 0;
1195         }
1196         dprintk("RPC:       %s succeeded\n", __func__);
1197
1198 out_release:
1199         sock_release(sock);
1200 out:
1201         return err;
1202 }
1203
1204 /*
1205  * Scraping a connected socket failed, so we don't have a useable
1206  * local address.  Fallback: generate an address that will prevent
1207  * the server from calling us back.
1208  *
1209  * Returns zero and fills in "buf" if successful; otherwise, a
1210  * negative errno is returned.
1211  */
1212 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1213 {
1214         switch (family) {
1215         case AF_INET:
1216                 if (buflen < sizeof(rpc_inaddr_loopback))
1217                         return -EINVAL;
1218                 memcpy(buf, &rpc_inaddr_loopback,
1219                                 sizeof(rpc_inaddr_loopback));
1220                 break;
1221         case AF_INET6:
1222                 if (buflen < sizeof(rpc_in6addr_loopback))
1223                         return -EINVAL;
1224                 memcpy(buf, &rpc_in6addr_loopback,
1225                                 sizeof(rpc_in6addr_loopback));
1226         default:
1227                 dprintk("RPC:       %s: address family not supported\n",
1228                         __func__);
1229                 return -EAFNOSUPPORT;
1230         }
1231         dprintk("RPC:       %s: succeeded\n", __func__);
1232         return 0;
1233 }
1234
1235 /**
1236  * rpc_localaddr - discover local endpoint address for an RPC client
1237  * @clnt: RPC client structure
1238  * @buf: target buffer
1239  * @buflen: size of target buffer, in bytes
1240  *
1241  * Returns zero and fills in "buf" and "buflen" if successful;
1242  * otherwise, a negative errno is returned.
1243  *
1244  * This works even if the underlying transport is not currently connected,
1245  * or if the upper layer never previously provided a source address.
1246  *
1247  * The result of this function call is transient: multiple calls in
1248  * succession may give different results, depending on how local
1249  * networking configuration changes over time.
1250  */
1251 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1252 {
1253         struct sockaddr_storage address;
1254         struct sockaddr *sap = (struct sockaddr *)&address;
1255         struct rpc_xprt *xprt;
1256         struct net *net;
1257         size_t salen;
1258         int err;
1259
1260         rcu_read_lock();
1261         xprt = rcu_dereference(clnt->cl_xprt);
1262         salen = xprt->addrlen;
1263         memcpy(sap, &xprt->addr, salen);
1264         net = get_net(xprt->xprt_net);
1265         rcu_read_unlock();
1266
1267         rpc_set_port(sap, 0);
1268         err = rpc_sockname(net, sap, salen, buf, buflen);
1269         put_net(net);
1270         if (err != 0)
1271                 /* Couldn't discover local address, return ANYADDR */
1272                 return rpc_anyaddr(sap->sa_family, buf, buflen);
1273         return 0;
1274 }
1275 EXPORT_SYMBOL_GPL(rpc_localaddr);
1276
1277 void
1278 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1279 {
1280         struct rpc_xprt *xprt;
1281
1282         rcu_read_lock();
1283         xprt = rcu_dereference(clnt->cl_xprt);
1284         if (xprt->ops->set_buffer_size)
1285                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1286         rcu_read_unlock();
1287 }
1288 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1289
1290 /**
1291  * rpc_protocol - Get transport protocol number for an RPC client
1292  * @clnt: RPC client to query
1293  *
1294  */
1295 int rpc_protocol(struct rpc_clnt *clnt)
1296 {
1297         int protocol;
1298
1299         rcu_read_lock();
1300         protocol = rcu_dereference(clnt->cl_xprt)->prot;
1301         rcu_read_unlock();
1302         return protocol;
1303 }
1304 EXPORT_SYMBOL_GPL(rpc_protocol);
1305
1306 /**
1307  * rpc_net_ns - Get the network namespace for this RPC client
1308  * @clnt: RPC client to query
1309  *
1310  */
1311 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1312 {
1313         struct net *ret;
1314
1315         rcu_read_lock();
1316         ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1317         rcu_read_unlock();
1318         return ret;
1319 }
1320 EXPORT_SYMBOL_GPL(rpc_net_ns);
1321
1322 /**
1323  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1324  * @clnt: RPC client to query
1325  *
1326  * For stream transports, this is one RPC record fragment (see RFC
1327  * 1831), as we don't support multi-record requests yet.  For datagram
1328  * transports, this is the size of an IP packet minus the IP, UDP, and
1329  * RPC header sizes.
1330  */
1331 size_t rpc_max_payload(struct rpc_clnt *clnt)
1332 {
1333         size_t ret;
1334
1335         rcu_read_lock();
1336         ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1337         rcu_read_unlock();
1338         return ret;
1339 }
1340 EXPORT_SYMBOL_GPL(rpc_max_payload);
1341
1342 /**
1343  * rpc_get_timeout - Get timeout for transport in units of HZ
1344  * @clnt: RPC client to query
1345  */
1346 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1347 {
1348         unsigned long ret;
1349
1350         rcu_read_lock();
1351         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1352         rcu_read_unlock();
1353         return ret;
1354 }
1355 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1356
1357 /**
1358  * rpc_force_rebind - force transport to check that remote port is unchanged
1359  * @clnt: client to rebind
1360  *
1361  */
1362 void rpc_force_rebind(struct rpc_clnt *clnt)
1363 {
1364         if (clnt->cl_autobind) {
1365                 rcu_read_lock();
1366                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1367                 rcu_read_unlock();
1368         }
1369 }
1370 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1371
1372 /*
1373  * Restart an (async) RPC call from the call_prepare state.
1374  * Usually called from within the exit handler.
1375  */
1376 int
1377 rpc_restart_call_prepare(struct rpc_task *task)
1378 {
1379         if (RPC_ASSASSINATED(task))
1380                 return 0;
1381         task->tk_action = call_start;
1382         task->tk_status = 0;
1383         if (task->tk_ops->rpc_call_prepare != NULL)
1384                 task->tk_action = rpc_prepare_task;
1385         return 1;
1386 }
1387 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1388
1389 /*
1390  * Restart an (async) RPC call. Usually called from within the
1391  * exit handler.
1392  */
1393 int
1394 rpc_restart_call(struct rpc_task *task)
1395 {
1396         if (RPC_ASSASSINATED(task))
1397                 return 0;
1398         task->tk_action = call_start;
1399         task->tk_status = 0;
1400         return 1;
1401 }
1402 EXPORT_SYMBOL_GPL(rpc_restart_call);
1403
1404 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1405 const char
1406 *rpc_proc_name(const struct rpc_task *task)
1407 {
1408         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1409
1410         if (proc) {
1411                 if (proc->p_name)
1412                         return proc->p_name;
1413                 else
1414                         return "NULL";
1415         } else
1416                 return "no proc";
1417 }
1418 #endif
1419
1420 /*
1421  * 0.  Initial state
1422  *
1423  *     Other FSM states can be visited zero or more times, but
1424  *     this state is visited exactly once for each RPC.
1425  */
1426 static void
1427 call_start(struct rpc_task *task)
1428 {
1429         struct rpc_clnt *clnt = task->tk_client;
1430
1431         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1432                         clnt->cl_program->name, clnt->cl_vers,
1433                         rpc_proc_name(task),
1434                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1435
1436         /* Increment call count */
1437         task->tk_msg.rpc_proc->p_count++;
1438         clnt->cl_stats->rpccnt++;
1439         task->tk_action = call_reserve;
1440 }
1441
1442 /*
1443  * 1.   Reserve an RPC call slot
1444  */
1445 static void
1446 call_reserve(struct rpc_task *task)
1447 {
1448         dprint_status(task);
1449
1450         task->tk_status  = 0;
1451         task->tk_action  = call_reserveresult;
1452         xprt_reserve(task);
1453 }
1454
1455 static void call_retry_reserve(struct rpc_task *task);
1456
1457 /*
1458  * 1b.  Grok the result of xprt_reserve()
1459  */
1460 static void
1461 call_reserveresult(struct rpc_task *task)
1462 {
1463         int status = task->tk_status;
1464
1465         dprint_status(task);
1466
1467         /*
1468          * After a call to xprt_reserve(), we must have either
1469          * a request slot or else an error status.
1470          */
1471         task->tk_status = 0;
1472         if (status >= 0) {
1473                 if (task->tk_rqstp) {
1474                         task->tk_action = call_refresh;
1475                         return;
1476                 }
1477
1478                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1479                                 __func__, status);
1480                 rpc_exit(task, -EIO);
1481                 return;
1482         }
1483
1484         /*
1485          * Even though there was an error, we may have acquired
1486          * a request slot somehow.  Make sure not to leak it.
1487          */
1488         if (task->tk_rqstp) {
1489                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1490                                 __func__, status);
1491                 xprt_release(task);
1492         }
1493
1494         switch (status) {
1495         case -ENOMEM:
1496                 rpc_delay(task, HZ >> 2);
1497         case -EAGAIN:   /* woken up; retry */
1498                 task->tk_action = call_retry_reserve;
1499                 return;
1500         case -EIO:      /* probably a shutdown */
1501                 break;
1502         default:
1503                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1504                                 __func__, status);
1505                 break;
1506         }
1507         rpc_exit(task, status);
1508 }
1509
1510 /*
1511  * 1c.  Retry reserving an RPC call slot
1512  */
1513 static void
1514 call_retry_reserve(struct rpc_task *task)
1515 {
1516         dprint_status(task);
1517
1518         task->tk_status  = 0;
1519         task->tk_action  = call_reserveresult;
1520         xprt_retry_reserve(task);
1521 }
1522
1523 /*
1524  * 2.   Bind and/or refresh the credentials
1525  */
1526 static void
1527 call_refresh(struct rpc_task *task)
1528 {
1529         dprint_status(task);
1530
1531         task->tk_action = call_refreshresult;
1532         task->tk_status = 0;
1533         task->tk_client->cl_stats->rpcauthrefresh++;
1534         rpcauth_refreshcred(task);
1535 }
1536
1537 /*
1538  * 2a.  Process the results of a credential refresh
1539  */
1540 static void
1541 call_refreshresult(struct rpc_task *task)
1542 {
1543         int status = task->tk_status;
1544
1545         dprint_status(task);
1546
1547         task->tk_status = 0;
1548         task->tk_action = call_refresh;
1549         switch (status) {
1550         case 0:
1551                 if (rpcauth_uptodatecred(task)) {
1552                         task->tk_action = call_allocate;
1553                         return;
1554                 }
1555                 /* Use rate-limiting and a max number of retries if refresh
1556                  * had status 0 but failed to update the cred.
1557                  */
1558         case -ETIMEDOUT:
1559                 rpc_delay(task, 3*HZ);
1560         case -EAGAIN:
1561                 status = -EACCES;
1562         case -EKEYEXPIRED:
1563                 if (!task->tk_cred_retry)
1564                         break;
1565                 task->tk_cred_retry--;
1566                 dprintk("RPC: %5u %s: retry refresh creds\n",
1567                                 task->tk_pid, __func__);
1568                 return;
1569         }
1570         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1571                                 task->tk_pid, __func__, status);
1572         rpc_exit(task, status);
1573 }
1574
1575 /*
1576  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1577  *      (Note: buffer memory is freed in xprt_release).
1578  */
1579 static void
1580 call_allocate(struct rpc_task *task)
1581 {
1582         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1583         struct rpc_rqst *req = task->tk_rqstp;
1584         struct rpc_xprt *xprt = req->rq_xprt;
1585         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1586
1587         dprint_status(task);
1588
1589         task->tk_status = 0;
1590         task->tk_action = call_bind;
1591
1592         if (req->rq_buffer)
1593                 return;
1594
1595         if (proc->p_proc != 0) {
1596                 BUG_ON(proc->p_arglen == 0);
1597                 if (proc->p_decode != NULL)
1598                         BUG_ON(proc->p_replen == 0);
1599         }
1600
1601         /*
1602          * Calculate the size (in quads) of the RPC call
1603          * and reply headers, and convert both values
1604          * to byte sizes.
1605          */
1606         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1607         req->rq_callsize <<= 2;
1608         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1609         req->rq_rcvsize <<= 2;
1610
1611         req->rq_buffer = xprt->ops->buf_alloc(task,
1612                                         req->rq_callsize + req->rq_rcvsize);
1613         if (req->rq_buffer != NULL)
1614                 return;
1615
1616         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1617
1618         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1619                 task->tk_action = call_allocate;
1620                 rpc_delay(task, HZ>>4);
1621                 return;
1622         }
1623
1624         rpc_exit(task, -ERESTARTSYS);
1625 }
1626
1627 static inline int
1628 rpc_task_need_encode(struct rpc_task *task)
1629 {
1630         return task->tk_rqstp->rq_snd_buf.len == 0;
1631 }
1632
1633 static inline void
1634 rpc_task_force_reencode(struct rpc_task *task)
1635 {
1636         task->tk_rqstp->rq_snd_buf.len = 0;
1637         task->tk_rqstp->rq_bytes_sent = 0;
1638 }
1639
1640 static inline void
1641 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1642 {
1643         buf->head[0].iov_base = start;
1644         buf->head[0].iov_len = len;
1645         buf->tail[0].iov_len = 0;
1646         buf->page_len = 0;
1647         buf->flags = 0;
1648         buf->len = 0;
1649         buf->buflen = len;
1650 }
1651
1652 /*
1653  * 3.   Encode arguments of an RPC call
1654  */
1655 static void
1656 rpc_xdr_encode(struct rpc_task *task)
1657 {
1658         struct rpc_rqst *req = task->tk_rqstp;
1659         kxdreproc_t     encode;
1660         __be32          *p;
1661
1662         dprint_status(task);
1663
1664         rpc_xdr_buf_init(&req->rq_snd_buf,
1665                          req->rq_buffer,
1666                          req->rq_callsize);
1667         rpc_xdr_buf_init(&req->rq_rcv_buf,
1668                          (char *)req->rq_buffer + req->rq_callsize,
1669                          req->rq_rcvsize);
1670
1671         p = rpc_encode_header(task);
1672         if (p == NULL) {
1673                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1674                 rpc_exit(task, -EIO);
1675                 return;
1676         }
1677
1678         encode = task->tk_msg.rpc_proc->p_encode;
1679         if (encode == NULL)
1680                 return;
1681
1682         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1683                         task->tk_msg.rpc_argp);
1684 }
1685
1686 /*
1687  * 4.   Get the server port number if not yet set
1688  */
1689 static void
1690 call_bind(struct rpc_task *task)
1691 {
1692         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1693
1694         dprint_status(task);
1695
1696         task->tk_action = call_connect;
1697         if (!xprt_bound(xprt)) {
1698                 task->tk_action = call_bind_status;
1699                 task->tk_timeout = xprt->bind_timeout;
1700                 xprt->ops->rpcbind(task);
1701         }
1702 }
1703
1704 /*
1705  * 4a.  Sort out bind result
1706  */
1707 static void
1708 call_bind_status(struct rpc_task *task)
1709 {
1710         int status = -EIO;
1711
1712         if (task->tk_status >= 0) {
1713                 dprint_status(task);
1714                 task->tk_status = 0;
1715                 task->tk_action = call_connect;
1716                 return;
1717         }
1718
1719         trace_rpc_bind_status(task);
1720         switch (task->tk_status) {
1721         case -ENOMEM:
1722                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1723                 rpc_delay(task, HZ >> 2);
1724                 goto retry_timeout;
1725         case -EACCES:
1726                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1727                                 "unavailable\n", task->tk_pid);
1728                 /* fail immediately if this is an RPC ping */
1729                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1730                         status = -EOPNOTSUPP;
1731                         break;
1732                 }
1733                 if (task->tk_rebind_retry == 0)
1734                         break;
1735                 task->tk_rebind_retry--;
1736                 rpc_delay(task, 3*HZ);
1737                 goto retry_timeout;
1738         case -ETIMEDOUT:
1739                 dprintk("RPC: %5u rpcbind request timed out\n",
1740                                 task->tk_pid);
1741                 goto retry_timeout;
1742         case -EPFNOSUPPORT:
1743                 /* server doesn't support any rpcbind version we know of */
1744                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1745                                 task->tk_pid);
1746                 break;
1747         case -EPROTONOSUPPORT:
1748                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1749                                 task->tk_pid);
1750                 goto retry_timeout;
1751         case -ECONNREFUSED:             /* connection problems */
1752         case -ECONNRESET:
1753         case -ECONNABORTED:
1754         case -ENOTCONN:
1755         case -EHOSTDOWN:
1756         case -EHOSTUNREACH:
1757         case -ENETUNREACH:
1758         case -ENOBUFS:
1759         case -EPIPE:
1760                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1761                                 task->tk_pid, task->tk_status);
1762                 if (!RPC_IS_SOFTCONN(task)) {
1763                         rpc_delay(task, 5*HZ);
1764                         goto retry_timeout;
1765                 }
1766                 status = task->tk_status;
1767                 break;
1768         default:
1769                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1770                                 task->tk_pid, -task->tk_status);
1771         }
1772
1773         rpc_exit(task, status);
1774         return;
1775
1776 retry_timeout:
1777         task->tk_status = 0;
1778         task->tk_action = call_timeout;
1779 }
1780
1781 /*
1782  * 4b.  Connect to the RPC server
1783  */
1784 static void
1785 call_connect(struct rpc_task *task)
1786 {
1787         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1788
1789         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1790                         task->tk_pid, xprt,
1791                         (xprt_connected(xprt) ? "is" : "is not"));
1792
1793         task->tk_action = call_transmit;
1794         if (!xprt_connected(xprt)) {
1795                 task->tk_action = call_connect_status;
1796                 if (task->tk_status < 0)
1797                         return;
1798                 if (task->tk_flags & RPC_TASK_NOCONNECT) {
1799                         rpc_exit(task, -ENOTCONN);
1800                         return;
1801                 }
1802                 xprt_connect(task);
1803         }
1804 }
1805
1806 /*
1807  * 4c.  Sort out connect result
1808  */
1809 static void
1810 call_connect_status(struct rpc_task *task)
1811 {
1812         struct rpc_clnt *clnt = task->tk_client;
1813         int status = task->tk_status;
1814
1815         dprint_status(task);
1816
1817         trace_rpc_connect_status(task, status);
1818         task->tk_status = 0;
1819         switch (status) {
1820         case -ECONNREFUSED:
1821         case -ECONNRESET:
1822         case -ECONNABORTED:
1823         case -ENETUNREACH:
1824         case -EHOSTUNREACH:
1825         case -EADDRINUSE:
1826         case -ENOBUFS:
1827         case -EPIPE:
1828                 if (RPC_IS_SOFTCONN(task))
1829                         break;
1830                 /* retry with existing socket, after a delay */
1831                 rpc_delay(task, 3*HZ);
1832         case -EAGAIN:
1833                 /* Check for timeouts before looping back to call_bind */
1834         case -ETIMEDOUT:
1835                 task->tk_action = call_timeout;
1836                 return;
1837         case 0:
1838                 clnt->cl_stats->netreconn++;
1839                 task->tk_action = call_transmit;
1840                 return;
1841         }
1842         rpc_exit(task, status);
1843 }
1844
1845 /*
1846  * 5.   Transmit the RPC request, and wait for reply
1847  */
1848 static void
1849 call_transmit(struct rpc_task *task)
1850 {
1851         int is_retrans = RPC_WAS_SENT(task);
1852
1853         dprint_status(task);
1854
1855         task->tk_action = call_status;
1856         if (task->tk_status < 0)
1857                 return;
1858         if (!xprt_prepare_transmit(task))
1859                 return;
1860         task->tk_action = call_transmit_status;
1861         /* Encode here so that rpcsec_gss can use correct sequence number. */
1862         if (rpc_task_need_encode(task)) {
1863                 rpc_xdr_encode(task);
1864                 /* Did the encode result in an error condition? */
1865                 if (task->tk_status != 0) {
1866                         /* Was the error nonfatal? */
1867                         if (task->tk_status == -EAGAIN)
1868                                 rpc_delay(task, HZ >> 4);
1869                         else
1870                                 rpc_exit(task, task->tk_status);
1871                         return;
1872                 }
1873         }
1874         xprt_transmit(task);
1875         if (task->tk_status < 0)
1876                 return;
1877         if (is_retrans)
1878                 task->tk_client->cl_stats->rpcretrans++;
1879         /*
1880          * On success, ensure that we call xprt_end_transmit() before sleeping
1881          * in order to allow access to the socket to other RPC requests.
1882          */
1883         call_transmit_status(task);
1884         if (rpc_reply_expected(task))
1885                 return;
1886         task->tk_action = rpc_exit_task;
1887         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1888 }
1889
1890 /*
1891  * 5a.  Handle cleanup after a transmission
1892  */
1893 static void
1894 call_transmit_status(struct rpc_task *task)
1895 {
1896         task->tk_action = call_status;
1897
1898         /*
1899          * Common case: success.  Force the compiler to put this
1900          * test first.
1901          */
1902         if (task->tk_status == 0) {
1903                 xprt_end_transmit(task);
1904                 rpc_task_force_reencode(task);
1905                 return;
1906         }
1907
1908         switch (task->tk_status) {
1909         case -EAGAIN:
1910                 break;
1911         default:
1912                 dprint_status(task);
1913                 xprt_end_transmit(task);
1914                 rpc_task_force_reencode(task);
1915                 break;
1916                 /*
1917                  * Special cases: if we've been waiting on the
1918                  * socket's write_space() callback, or if the
1919                  * socket just returned a connection error,
1920                  * then hold onto the transport lock.
1921                  */
1922         case -ECONNREFUSED:
1923         case -EHOSTDOWN:
1924         case -EHOSTUNREACH:
1925         case -ENETUNREACH:
1926         case -EPERM:
1927                 if (RPC_IS_SOFTCONN(task)) {
1928                         xprt_end_transmit(task);
1929                         rpc_exit(task, task->tk_status);
1930                         break;
1931                 }
1932         case -ECONNRESET:
1933         case -ECONNABORTED:
1934         case -EADDRINUSE:
1935         case -ENOTCONN:
1936         case -ENOBUFS:
1937         case -EPIPE:
1938                 rpc_task_force_reencode(task);
1939         }
1940 }
1941
1942 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1943 /*
1944  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1945  * addition, disconnect on connectivity errors.
1946  */
1947 static void
1948 call_bc_transmit(struct rpc_task *task)
1949 {
1950         struct rpc_rqst *req = task->tk_rqstp;
1951
1952         if (!xprt_prepare_transmit(task))
1953                 goto out_retry;
1954
1955         if (task->tk_status < 0) {
1956                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1957                         "error: %d\n", task->tk_status);
1958                 goto out_done;
1959         }
1960         if (req->rq_connect_cookie != req->rq_xprt->connect_cookie)
1961                 req->rq_bytes_sent = 0;
1962
1963         xprt_transmit(task);
1964
1965         if (task->tk_status == -EAGAIN)
1966                 goto out_nospace;
1967
1968         xprt_end_transmit(task);
1969         dprint_status(task);
1970         switch (task->tk_status) {
1971         case 0:
1972                 /* Success */
1973                 break;
1974         case -EHOSTDOWN:
1975         case -EHOSTUNREACH:
1976         case -ENETUNREACH:
1977         case -ETIMEDOUT:
1978                 /*
1979                  * Problem reaching the server.  Disconnect and let the
1980                  * forechannel reestablish the connection.  The server will
1981                  * have to retransmit the backchannel request and we'll
1982                  * reprocess it.  Since these ops are idempotent, there's no
1983                  * need to cache our reply at this time.
1984                  */
1985                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1986                         "error: %d\n", task->tk_status);
1987                 xprt_conditional_disconnect(req->rq_xprt,
1988                         req->rq_connect_cookie);
1989                 break;
1990         default:
1991                 /*
1992                  * We were unable to reply and will have to drop the
1993                  * request.  The server should reconnect and retransmit.
1994                  */
1995                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
1996                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1997                         "error: %d\n", task->tk_status);
1998                 break;
1999         }
2000         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
2001 out_done:
2002         task->tk_action = rpc_exit_task;
2003         return;
2004 out_nospace:
2005         req->rq_connect_cookie = req->rq_xprt->connect_cookie;
2006 out_retry:
2007         task->tk_status = 0;
2008 }
2009 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
2010
2011 /*
2012  * 6.   Sort out the RPC call status
2013  */
2014 static void
2015 call_status(struct rpc_task *task)
2016 {
2017         struct rpc_clnt *clnt = task->tk_client;
2018         struct rpc_rqst *req = task->tk_rqstp;
2019         int             status;
2020
2021         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
2022                 task->tk_status = req->rq_reply_bytes_recvd;
2023
2024         dprint_status(task);
2025
2026         status = task->tk_status;
2027         if (status >= 0) {
2028                 task->tk_action = call_decode;
2029                 return;
2030         }
2031
2032         trace_rpc_call_status(task);
2033         task->tk_status = 0;
2034         switch(status) {
2035         case -EHOSTDOWN:
2036         case -EHOSTUNREACH:
2037         case -ENETUNREACH:
2038         case -EPERM:
2039                 if (RPC_IS_SOFTCONN(task)) {
2040                         rpc_exit(task, status);
2041                         break;
2042                 }
2043                 /*
2044                  * Delay any retries for 3 seconds, then handle as if it
2045                  * were a timeout.
2046                  */
2047                 rpc_delay(task, 3*HZ);
2048         case -ETIMEDOUT:
2049                 task->tk_action = call_timeout;
2050                 if (!(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
2051                     && task->tk_client->cl_discrtry)
2052                         xprt_conditional_disconnect(req->rq_xprt,
2053                                         req->rq_connect_cookie);
2054                 break;
2055         case -ECONNREFUSED:
2056         case -ECONNRESET:
2057         case -ECONNABORTED:
2058                 rpc_force_rebind(clnt);
2059         case -EADDRINUSE:
2060         case -ENOBUFS:
2061                 rpc_delay(task, 3*HZ);
2062         case -EPIPE:
2063         case -ENOTCONN:
2064                 task->tk_action = call_bind;
2065                 break;
2066         case -EAGAIN:
2067                 task->tk_action = call_transmit;
2068                 break;
2069         case -EIO:
2070                 /* shutdown or soft timeout */
2071                 rpc_exit(task, status);
2072                 break;
2073         default:
2074                 if (clnt->cl_chatty)
2075                         printk("%s: RPC call returned error %d\n",
2076                                clnt->cl_program->name, -status);
2077                 rpc_exit(task, status);
2078         }
2079 }
2080
2081 /*
2082  * 6a.  Handle RPC timeout
2083  *      We do not release the request slot, so we keep using the
2084  *      same XID for all retransmits.
2085  */
2086 static void
2087 call_timeout(struct rpc_task *task)
2088 {
2089         struct rpc_clnt *clnt = task->tk_client;
2090
2091         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
2092                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
2093                 goto retry;
2094         }
2095
2096         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
2097         task->tk_timeouts++;
2098
2099         if (RPC_IS_SOFTCONN(task)) {
2100                 rpc_exit(task, -ETIMEDOUT);
2101                 return;
2102         }
2103         if (RPC_IS_SOFT(task)) {
2104                 if (clnt->cl_chatty) {
2105                         rcu_read_lock();
2106                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
2107                                 clnt->cl_program->name,
2108                                 rcu_dereference(clnt->cl_xprt)->servername);
2109                         rcu_read_unlock();
2110                 }
2111                 if (task->tk_flags & RPC_TASK_TIMEOUT)
2112                         rpc_exit(task, -ETIMEDOUT);
2113                 else
2114                         rpc_exit(task, -EIO);
2115                 return;
2116         }
2117
2118         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2119                 task->tk_flags |= RPC_CALL_MAJORSEEN;
2120                 if (clnt->cl_chatty) {
2121                         rcu_read_lock();
2122                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
2123                         clnt->cl_program->name,
2124                         rcu_dereference(clnt->cl_xprt)->servername);
2125                         rcu_read_unlock();
2126                 }
2127         }
2128         rpc_force_rebind(clnt);
2129         /*
2130          * Did our request time out due to an RPCSEC_GSS out-of-sequence
2131          * event? RFC2203 requires the server to drop all such requests.
2132          */
2133         rpcauth_invalcred(task);
2134
2135 retry:
2136         task->tk_action = call_bind;
2137         task->tk_status = 0;
2138 }
2139
2140 /*
2141  * 7.   Decode the RPC reply
2142  */
2143 static void
2144 call_decode(struct rpc_task *task)
2145 {
2146         struct rpc_clnt *clnt = task->tk_client;
2147         struct rpc_rqst *req = task->tk_rqstp;
2148         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
2149         __be32          *p;
2150
2151         dprint_status(task);
2152
2153         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2154                 if (clnt->cl_chatty) {
2155                         rcu_read_lock();
2156                         printk(KERN_NOTICE "%s: server %s OK\n",
2157                                 clnt->cl_program->name,
2158                                 rcu_dereference(clnt->cl_xprt)->servername);
2159                         rcu_read_unlock();
2160                 }
2161                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2162         }
2163
2164         /*
2165          * Ensure that we see all writes made by xprt_complete_rqst()
2166          * before it changed req->rq_reply_bytes_recvd.
2167          */
2168         smp_rmb();
2169         req->rq_rcv_buf.len = req->rq_private_buf.len;
2170
2171         /* Check that the softirq receive buffer is valid */
2172         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2173                                 sizeof(req->rq_rcv_buf)) != 0);
2174
2175         if (req->rq_rcv_buf.len < 12) {
2176                 if (!RPC_IS_SOFT(task)) {
2177                         task->tk_action = call_bind;
2178                         goto out_retry;
2179                 }
2180                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2181                                 clnt->cl_program->name, task->tk_status);
2182                 task->tk_action = call_timeout;
2183                 goto out_retry;
2184         }
2185
2186         p = rpc_verify_header(task);
2187         if (IS_ERR(p)) {
2188                 if (p == ERR_PTR(-EAGAIN))
2189                         goto out_retry;
2190                 return;
2191         }
2192
2193         task->tk_action = rpc_exit_task;
2194
2195         if (decode) {
2196                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2197                                                       task->tk_msg.rpc_resp);
2198         }
2199         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2200                         task->tk_status);
2201         return;
2202 out_retry:
2203         task->tk_status = 0;
2204         /* Note: rpc_verify_header() may have freed the RPC slot */
2205         if (task->tk_rqstp == req) {
2206                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2207                 if (task->tk_client->cl_discrtry)
2208                         xprt_conditional_disconnect(req->rq_xprt,
2209                                         req->rq_connect_cookie);
2210         }
2211 }
2212
2213 static __be32 *
2214 rpc_encode_header(struct rpc_task *task)
2215 {
2216         struct rpc_clnt *clnt = task->tk_client;
2217         struct rpc_rqst *req = task->tk_rqstp;
2218         __be32          *p = req->rq_svec[0].iov_base;
2219
2220         /* FIXME: check buffer size? */
2221
2222         p = xprt_skip_transport_header(req->rq_xprt, p);
2223         *p++ = req->rq_xid;             /* XID */
2224         *p++ = htonl(RPC_CALL);         /* CALL */
2225         *p++ = htonl(RPC_VERSION);      /* RPC version */
2226         *p++ = htonl(clnt->cl_prog);    /* program number */
2227         *p++ = htonl(clnt->cl_vers);    /* program version */
2228         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2229         p = rpcauth_marshcred(task, p);
2230         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2231         return p;
2232 }
2233
2234 static __be32 *
2235 rpc_verify_header(struct rpc_task *task)
2236 {
2237         struct rpc_clnt *clnt = task->tk_client;
2238         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2239         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2240         __be32  *p = iov->iov_base;
2241         u32 n;
2242         int error = -EACCES;
2243
2244         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2245                 /* RFC-1014 says that the representation of XDR data must be a
2246                  * multiple of four bytes
2247                  * - if it isn't pointer subtraction in the NFS client may give
2248                  *   undefined results
2249                  */
2250                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2251                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2252                        task->tk_rqstp->rq_rcv_buf.len);
2253                 error = -EIO;
2254                 goto out_err;
2255         }
2256         if ((len -= 3) < 0)
2257                 goto out_overflow;
2258
2259         p += 1; /* skip XID */
2260         if ((n = ntohl(*p++)) != RPC_REPLY) {
2261                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2262                         task->tk_pid, __func__, n);
2263                 error = -EIO;
2264                 goto out_garbage;
2265         }
2266
2267         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2268                 if (--len < 0)
2269                         goto out_overflow;
2270                 switch ((n = ntohl(*p++))) {
2271                 case RPC_AUTH_ERROR:
2272                         break;
2273                 case RPC_MISMATCH:
2274                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2275                                 task->tk_pid, __func__);
2276                         error = -EPROTONOSUPPORT;
2277                         goto out_err;
2278                 default:
2279                         dprintk("RPC: %5u %s: RPC call rejected, "
2280                                 "unknown error: %x\n",
2281                                 task->tk_pid, __func__, n);
2282                         error = -EIO;
2283                         goto out_err;
2284                 }
2285                 if (--len < 0)
2286                         goto out_overflow;
2287                 switch ((n = ntohl(*p++))) {
2288                 case RPC_AUTH_REJECTEDCRED:
2289                 case RPC_AUTH_REJECTEDVERF:
2290                 case RPCSEC_GSS_CREDPROBLEM:
2291                 case RPCSEC_GSS_CTXPROBLEM:
2292                         if (!task->tk_cred_retry)
2293                                 break;
2294                         task->tk_cred_retry--;
2295                         dprintk("RPC: %5u %s: retry stale creds\n",
2296                                         task->tk_pid, __func__);
2297                         rpcauth_invalcred(task);
2298                         /* Ensure we obtain a new XID! */
2299                         xprt_release(task);
2300                         task->tk_action = call_reserve;
2301                         goto out_retry;
2302                 case RPC_AUTH_BADCRED:
2303                 case RPC_AUTH_BADVERF:
2304                         /* possibly garbled cred/verf? */
2305                         if (!task->tk_garb_retry)
2306                                 break;
2307                         task->tk_garb_retry--;
2308                         dprintk("RPC: %5u %s: retry garbled creds\n",
2309                                         task->tk_pid, __func__);
2310                         task->tk_action = call_bind;
2311                         goto out_retry;
2312                 case RPC_AUTH_TOOWEAK:
2313                         rcu_read_lock();
2314                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2315                                "authentication.\n",
2316                                rcu_dereference(clnt->cl_xprt)->servername);
2317                         rcu_read_unlock();
2318                         break;
2319                 default:
2320                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2321                                         task->tk_pid, __func__, n);
2322                         error = -EIO;
2323                 }
2324                 dprintk("RPC: %5u %s: call rejected %d\n",
2325                                 task->tk_pid, __func__, n);
2326                 goto out_err;
2327         }
2328         p = rpcauth_checkverf(task, p);
2329         if (IS_ERR(p)) {
2330                 error = PTR_ERR(p);
2331                 dprintk("RPC: %5u %s: auth check failed with %d\n",
2332                                 task->tk_pid, __func__, error);
2333                 goto out_garbage;               /* bad verifier, retry */
2334         }
2335         len = p - (__be32 *)iov->iov_base - 1;
2336         if (len < 0)
2337                 goto out_overflow;
2338         switch ((n = ntohl(*p++))) {
2339         case RPC_SUCCESS:
2340                 return p;
2341         case RPC_PROG_UNAVAIL:
2342                 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2343                                 "by server %s\n", task->tk_pid, __func__,
2344                                 (unsigned int)clnt->cl_prog,
2345                                 rcu_dereference(clnt->cl_xprt)->servername);
2346                 error = -EPFNOSUPPORT;
2347                 goto out_err;
2348         case RPC_PROG_MISMATCH:
2349                 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2350                                 "by server %s\n", task->tk_pid, __func__,
2351                                 (unsigned int)clnt->cl_prog,
2352                                 (unsigned int)clnt->cl_vers,
2353                                 rcu_dereference(clnt->cl_xprt)->servername);
2354                 error = -EPROTONOSUPPORT;
2355                 goto out_err;
2356         case RPC_PROC_UNAVAIL:
2357                 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2358                                 "version %u on server %s\n",
2359                                 task->tk_pid, __func__,
2360                                 rpc_proc_name(task),
2361                                 clnt->cl_prog, clnt->cl_vers,
2362                                 rcu_dereference(clnt->cl_xprt)->servername);
2363                 error = -EOPNOTSUPP;
2364                 goto out_err;
2365         case RPC_GARBAGE_ARGS:
2366                 dprintk("RPC: %5u %s: server saw garbage\n",
2367                                 task->tk_pid, __func__);
2368                 break;                  /* retry */
2369         default:
2370                 dprintk("RPC: %5u %s: server accept status: %x\n",
2371                                 task->tk_pid, __func__, n);
2372                 /* Also retry */
2373         }
2374
2375 out_garbage:
2376         clnt->cl_stats->rpcgarbage++;
2377         if (task->tk_garb_retry) {
2378                 task->tk_garb_retry--;
2379                 dprintk("RPC: %5u %s: retrying\n",
2380                                 task->tk_pid, __func__);
2381                 task->tk_action = call_bind;
2382 out_retry:
2383                 return ERR_PTR(-EAGAIN);
2384         }
2385 out_err:
2386         rpc_exit(task, error);
2387         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2388                         __func__, error);
2389         return ERR_PTR(error);
2390 out_overflow:
2391         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2392                         __func__);
2393         goto out_garbage;
2394 }
2395
2396 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2397 {
2398 }
2399
2400 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2401 {
2402         return 0;
2403 }
2404
2405 static struct rpc_procinfo rpcproc_null = {
2406         .p_encode = rpcproc_encode_null,
2407         .p_decode = rpcproc_decode_null,
2408 };
2409
2410 static int rpc_ping(struct rpc_clnt *clnt)
2411 {
2412         struct rpc_message msg = {
2413                 .rpc_proc = &rpcproc_null,
2414         };
2415         int err;
2416         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2417         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2418         put_rpccred(msg.rpc_cred);
2419         return err;
2420 }
2421
2422 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2423 {
2424         struct rpc_message msg = {
2425                 .rpc_proc = &rpcproc_null,
2426                 .rpc_cred = cred,
2427         };
2428         struct rpc_task_setup task_setup_data = {
2429                 .rpc_client = clnt,
2430                 .rpc_message = &msg,
2431                 .callback_ops = &rpc_default_ops,
2432                 .flags = flags,
2433         };
2434         return rpc_run_task(&task_setup_data);
2435 }
2436 EXPORT_SYMBOL_GPL(rpc_call_null);
2437
2438 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
2439 static void rpc_show_header(void)
2440 {
2441         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2442                 "-timeout ---ops--\n");
2443 }
2444
2445 static void rpc_show_task(const struct rpc_clnt *clnt,
2446                           const struct rpc_task *task)
2447 {
2448         const char *rpc_waitq = "none";
2449
2450         if (RPC_IS_QUEUED(task))
2451                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2452
2453         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2454                 task->tk_pid, task->tk_flags, task->tk_status,
2455                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2456                 clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
2457                 task->tk_action, rpc_waitq);
2458 }
2459
2460 void rpc_show_tasks(struct net *net)
2461 {
2462         struct rpc_clnt *clnt;
2463         struct rpc_task *task;
2464         int header = 0;
2465         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2466
2467         spin_lock(&sn->rpc_client_lock);
2468         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2469                 spin_lock(&clnt->cl_lock);
2470                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2471                         if (!header) {
2472                                 rpc_show_header();
2473                                 header++;
2474                         }
2475                         rpc_show_task(clnt, task);
2476                 }
2477                 spin_unlock(&clnt->cl_lock);
2478         }
2479         spin_unlock(&sn->rpc_client_lock);
2480 }
2481 #endif