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 (atomic_read(&clnt->cl_swapper))
 895                         task->tk_flags |= RPC_TASK_SWAPPER;
 896                 /* Add to the client's list of all tasks */
 897                 spin_lock(&clnt->cl_lock);
 898                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 899                 spin_unlock(&clnt->cl_lock);
 900         }
 901 }
 902
 903 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 904 {
 905         rpc_task_release_client(task);
 906         rpc_task_set_client(task, clnt);
 907 }
 908 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 909
 910
 911 static void
 912 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 913 {
 914         if (msg != NULL) {
 915                 task->tk_msg.rpc_proc = msg->rpc_proc;
 916                 task->tk_msg.rpc_argp = msg->rpc_argp;
 917                 task->tk_msg.rpc_resp = msg->rpc_resp;
 918                 if (msg->rpc_cred != NULL)
 919                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 920         }
 921 }
 922
 923 /*
 924  * Default callback for async RPC calls
 925  */
 926 static void
 927 rpc_default_callback(struct rpc_task *task, void *data)
 928 {
 929 }
 930
 931 static const struct rpc_call_ops rpc_default_ops = {
 932         .rpc_call_done = rpc_default_callback,
 933 };
 934
 935 /**
 936  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 937  * @task_setup_data: pointer to task initialisation data
 938  */
 939 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 940 {
 941         struct rpc_task *task;
 942
 943         task = rpc_new_task(task_setup_data);
 944         if (IS_ERR(task))
 945                 goto out;
 946
 947         rpc_task_set_client(task, task_setup_data->rpc_client);
 948         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 949
 950         if (task->tk_action == NULL)
 951                 rpc_call_start(task);
 952
 953         atomic_inc(&task->tk_count);
 954         rpc_execute(task);
 955 out:
 956         return task;
 957 }
 958 EXPORT_SYMBOL_GPL(rpc_run_task);
 959
 960 /**
 961  * rpc_call_sync - Perform a synchronous RPC call
 962  * @clnt: pointer to RPC client
 963  * @msg: RPC call parameters
 964  * @flags: RPC call flags
 965  */
 966 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 967 {
 968         struct rpc_task *task;
 969         struct rpc_task_setup task_setup_data = {
 970                 .rpc_client = clnt,
 971                 .rpc_message = msg,
 972                 .callback_ops = &rpc_default_ops,
 973                 .flags = flags,
 974         };
 975         int status;
 976
 977         WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
 978         if (flags & RPC_TASK_ASYNC) {
 979                 rpc_release_calldata(task_setup_data.callback_ops,
 980                         task_setup_data.callback_data);
 981                 return -EINVAL;
 982         }
 983
 984         task = rpc_run_task(&task_setup_data);
 985         if (IS_ERR(task))
 986                 return PTR_ERR(task);
 987         status = task->tk_status;
 988         rpc_put_task(task);
 989         return status;
 990 }
 991 EXPORT_SYMBOL_GPL(rpc_call_sync);
 992
 993 /**
 994  * rpc_call_async - Perform an asynchronous RPC call
 995  * @clnt: pointer to RPC client
 996  * @msg: RPC call parameters
 997  * @flags: RPC call flags
 998  * @tk_ops: RPC call ops
 999  * @data: user call data
1000  */
1001 int
1002 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
1003                const struct rpc_call_ops *tk_ops, void *data)
1004 {
1005         struct rpc_task *task;
1006         struct rpc_task_setup task_setup_data = {
1007                 .rpc_client = clnt,
1008                 .rpc_message = msg,
1009                 .callback_ops = tk_ops,
1010                 .callback_data = data,
1011                 .flags = flags|RPC_TASK_ASYNC,
1012         };
1013
1014         task = rpc_run_task(&task_setup_data);
1015         if (IS_ERR(task))
1016                 return PTR_ERR(task);
1017         rpc_put_task(task);
1018         return 0;
1019 }
1020 EXPORT_SYMBOL_GPL(rpc_call_async);
1021
1022 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1023 /**
1024  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1025  * rpc_execute against it
1026  * @req: RPC request
1027  */
1028 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req)
1029 {
1030         struct rpc_task *task;
1031         struct xdr_buf *xbufp = &req->rq_snd_buf;
1032         struct rpc_task_setup task_setup_data = {
1033                 .callback_ops = &rpc_default_ops,
1034                 .flags = RPC_TASK_SOFTCONN,
1035         };
1036
1037         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
1038         /*
1039          * Create an rpc_task to send the data
1040          */
1041         task = rpc_new_task(&task_setup_data);
1042         if (IS_ERR(task)) {
1043                 xprt_free_bc_request(req);
1044                 goto out;
1045         }
1046         task->tk_rqstp = req;
1047
1048         /*
1049          * Set up the xdr_buf length.
1050          * This also indicates that the buffer is XDR encoded already.
1051          */
1052         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
1053                         xbufp->tail[0].iov_len;
1054
1055         task->tk_action = call_bc_transmit;
1056         atomic_inc(&task->tk_count);
1057         WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
1058         rpc_execute(task);
1059
1060 out:
1061         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
1062         return task;
1063 }
1064 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1065
1066 void
1067 rpc_call_start(struct rpc_task *task)
1068 {
1069         task->tk_action = call_start;
1070 }
1071 EXPORT_SYMBOL_GPL(rpc_call_start);
1072
1073 /**
1074  * rpc_peeraddr - extract remote peer address from clnt's xprt
1075  * @clnt: RPC client structure
1076  * @buf: target buffer
1077  * @bufsize: length of target buffer
1078  *
1079  * Returns the number of bytes that are actually in the stored address.
1080  */
1081 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
1082 {
1083         size_t bytes;
1084         struct rpc_xprt *xprt;
1085
1086         rcu_read_lock();
1087         xprt = rcu_dereference(clnt->cl_xprt);
1088
1089         bytes = xprt->addrlen;
1090         if (bytes > bufsize)
1091                 bytes = bufsize;
1092         memcpy(buf, &xprt->addr, bytes);
1093         rcu_read_unlock();
1094
1095         return bytes;
1096 }
1097 EXPORT_SYMBOL_GPL(rpc_peeraddr);
1098
1099 /**
1100  * rpc_peeraddr2str - return remote peer address in printable format
1101  * @clnt: RPC client structure
1102  * @format: address format
1103  *
1104  * NB: the lifetime of the memory referenced by the returned pointer is
1105  * the same as the rpc_xprt itself.  As long as the caller uses this
1106  * pointer, it must hold the RCU read lock.
1107  */
1108 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
1109                              enum rpc_display_format_t format)
1110 {
1111         struct rpc_xprt *xprt;
1112
1113         xprt = rcu_dereference(clnt->cl_xprt);
1114
1115         if (xprt->address_strings[format] != NULL)
1116                 return xprt->address_strings[format];
1117         else
1118                 return "unprintable";
1119 }
1120 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
1121
1122 static const struct sockaddr_in rpc_inaddr_loopback = {
1123         .sin_family             = AF_INET,
1124         .sin_addr.s_addr        = htonl(INADDR_ANY),
1125 };
1126
1127 static const struct sockaddr_in6 rpc_in6addr_loopback = {
1128         .sin6_family            = AF_INET6,
1129         .sin6_addr              = IN6ADDR_ANY_INIT,
1130 };
1131
1132 /*
1133  * Try a getsockname() on a connected datagram socket.  Using a
1134  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1135  * This conserves the ephemeral port number space.
1136  *
1137  * Returns zero and fills in "buf" if successful; otherwise, a
1138  * negative errno is returned.
1139  */
1140 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1141                         struct sockaddr *buf, int buflen)
1142 {
1143         struct socket *sock;
1144         int err;
1145
1146         err = __sock_create(net, sap->sa_family,
1147                                 SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1148         if (err < 0) {
1149                 dprintk("RPC:       can't create UDP socket (%d)\n", err);
1150                 goto out;
1151         }
1152
1153         switch (sap->sa_family) {
1154         case AF_INET:
1155                 err = kernel_bind(sock,
1156                                 (struct sockaddr *)&rpc_inaddr_loopback,
1157                                 sizeof(rpc_inaddr_loopback));
1158                 break;
1159         case AF_INET6:
1160                 err = kernel_bind(sock,
1161                                 (struct sockaddr *)&rpc_in6addr_loopback,
1162                                 sizeof(rpc_in6addr_loopback));
1163                 break;
1164         default:
1165                 err = -EAFNOSUPPORT;
1166                 goto out;
1167         }
1168         if (err < 0) {
1169                 dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1170                 goto out_release;
1171         }
1172
1173         err = kernel_connect(sock, sap, salen, 0);
1174         if (err < 0) {
1175                 dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1176                 goto out_release;
1177         }
1178
1179         err = kernel_getsockname(sock, buf, &buflen);
1180         if (err < 0) {
1181                 dprintk("RPC:       getsockname failed (%d)\n", err);
1182                 goto out_release;
1183         }
1184
1185         err = 0;
1186         if (buf->sa_family == AF_INET6) {
1187                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1188                 sin6->sin6_scope_id = 0;
1189         }
1190         dprintk("RPC:       %s succeeded\n", __func__);
1191
1192 out_release:
1193         sock_release(sock);
1194 out:
1195         return err;
1196 }
1197
1198 /*
1199  * Scraping a connected socket failed, so we don't have a useable
1200  * local address.  Fallback: generate an address that will prevent
1201  * the server from calling us back.
1202  *
1203  * Returns zero and fills in "buf" if successful; otherwise, a
1204  * negative errno is returned.
1205  */
1206 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1207 {
1208         switch (family) {
1209         case AF_INET:
1210                 if (buflen < sizeof(rpc_inaddr_loopback))
1211                         return -EINVAL;
1212                 memcpy(buf, &rpc_inaddr_loopback,
1213                                 sizeof(rpc_inaddr_loopback));
1214                 break;
1215         case AF_INET6:
1216                 if (buflen < sizeof(rpc_in6addr_loopback))
1217                         return -EINVAL;
1218                 memcpy(buf, &rpc_in6addr_loopback,
1219                                 sizeof(rpc_in6addr_loopback));
1220                 break;
1221         default:
1222                 dprintk("RPC:       %s: address family not supported\n",
1223                         __func__);
1224                 return -EAFNOSUPPORT;
1225         }
1226         dprintk("RPC:       %s: succeeded\n", __func__);
1227         return 0;
1228 }
1229
1230 /**
1231  * rpc_localaddr - discover local endpoint address for an RPC client
1232  * @clnt: RPC client structure
1233  * @buf: target buffer
1234  * @buflen: size of target buffer, in bytes
1235  *
1236  * Returns zero and fills in "buf" and "buflen" if successful;
1237  * otherwise, a negative errno is returned.
1238  *
1239  * This works even if the underlying transport is not currently connected,
1240  * or if the upper layer never previously provided a source address.
1241  *
1242  * The result of this function call is transient: multiple calls in
1243  * succession may give different results, depending on how local
1244  * networking configuration changes over time.
1245  */
1246 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1247 {
1248         struct sockaddr_storage address;
1249         struct sockaddr *sap = (struct sockaddr *)&address;
1250         struct rpc_xprt *xprt;
1251         struct net *net;
1252         size_t salen;
1253         int err;
1254
1255         rcu_read_lock();
1256         xprt = rcu_dereference(clnt->cl_xprt);
1257         salen = xprt->addrlen;
1258         memcpy(sap, &xprt->addr, salen);
1259         net = get_net(xprt->xprt_net);
1260         rcu_read_unlock();
1261
1262         rpc_set_port(sap, 0);
1263         err = rpc_sockname(net, sap, salen, buf, buflen);
1264         put_net(net);
1265         if (err != 0)
1266                 /* Couldn't discover local address, return ANYADDR */
1267                 return rpc_anyaddr(sap->sa_family, buf, buflen);
1268         return 0;
1269 }
1270 EXPORT_SYMBOL_GPL(rpc_localaddr);
1271
1272 void
1273 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1274 {
1275         struct rpc_xprt *xprt;
1276
1277         rcu_read_lock();
1278         xprt = rcu_dereference(clnt->cl_xprt);
1279         if (xprt->ops->set_buffer_size)
1280                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1281         rcu_read_unlock();
1282 }
1283 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1284
1285 /**
1286  * rpc_protocol - Get transport protocol number for an RPC client
1287  * @clnt: RPC client to query
1288  *
1289  */
1290 int rpc_protocol(struct rpc_clnt *clnt)
1291 {
1292         int protocol;
1293
1294         rcu_read_lock();
1295         protocol = rcu_dereference(clnt->cl_xprt)->prot;
1296         rcu_read_unlock();
1297         return protocol;
1298 }
1299 EXPORT_SYMBOL_GPL(rpc_protocol);
1300
1301 /**
1302  * rpc_net_ns - Get the network namespace for this RPC client
1303  * @clnt: RPC client to query
1304  *
1305  */
1306 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1307 {
1308         struct net *ret;
1309
1310         rcu_read_lock();
1311         ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1312         rcu_read_unlock();
1313         return ret;
1314 }
1315 EXPORT_SYMBOL_GPL(rpc_net_ns);
1316
1317 /**
1318  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1319  * @clnt: RPC client to query
1320  *
1321  * For stream transports, this is one RPC record fragment (see RFC
1322  * 1831), as we don't support multi-record requests yet.  For datagram
1323  * transports, this is the size of an IP packet minus the IP, UDP, and
1324  * RPC header sizes.
1325  */
1326 size_t rpc_max_payload(struct rpc_clnt *clnt)
1327 {
1328         size_t ret;
1329
1330         rcu_read_lock();
1331         ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1332         rcu_read_unlock();
1333         return ret;
1334 }
1335 EXPORT_SYMBOL_GPL(rpc_max_payload);
1336
1337 /**
1338  * rpc_get_timeout - Get timeout for transport in units of HZ
1339  * @clnt: RPC client to query
1340  */
1341 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1342 {
1343         unsigned long ret;
1344
1345         rcu_read_lock();
1346         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1347         rcu_read_unlock();
1348         return ret;
1349 }
1350 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1351
1352 /**
1353  * rpc_force_rebind - force transport to check that remote port is unchanged
1354  * @clnt: client to rebind
1355  *
1356  */
1357 void rpc_force_rebind(struct rpc_clnt *clnt)
1358 {
1359         if (clnt->cl_autobind) {
1360                 rcu_read_lock();
1361                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1362                 rcu_read_unlock();
1363         }
1364 }
1365 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1366
1367 /*
1368  * Restart an (async) RPC call from the call_prepare state.
1369  * Usually called from within the exit handler.
1370  */
1371 int
1372 rpc_restart_call_prepare(struct rpc_task *task)
1373 {
1374         if (RPC_ASSASSINATED(task))
1375                 return 0;
1376         task->tk_action = call_start;
1377         task->tk_status = 0;
1378         if (task->tk_ops->rpc_call_prepare != NULL)
1379                 task->tk_action = rpc_prepare_task;
1380         return 1;
1381 }
1382 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1383
1384 /*
1385  * Restart an (async) RPC call. Usually called from within the
1386  * exit handler.
1387  */
1388 int
1389 rpc_restart_call(struct rpc_task *task)
1390 {
1391         if (RPC_ASSASSINATED(task))
1392                 return 0;
1393         task->tk_action = call_start;
1394         task->tk_status = 0;
1395         return 1;
1396 }
1397 EXPORT_SYMBOL_GPL(rpc_restart_call);
1398
1399 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1400 const char
1401 *rpc_proc_name(const struct rpc_task *task)
1402 {
1403         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1404
1405         if (proc) {
1406                 if (proc->p_name)
1407                         return proc->p_name;
1408                 else
1409                         return "NULL";
1410         } else
1411                 return "no proc";
1412 }
1413 #endif
1414
1415 /*
1416  * 0.  Initial state
1417  *
1418  *     Other FSM states can be visited zero or more times, but
1419  *     this state is visited exactly once for each RPC.
1420  */
1421 static void
1422 call_start(struct rpc_task *task)
1423 {
1424         struct rpc_clnt *clnt = task->tk_client;
1425
1426         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1427                         clnt->cl_program->name, clnt->cl_vers,
1428                         rpc_proc_name(task),
1429                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1430
1431         /* Increment call count */
1432         task->tk_msg.rpc_proc->p_count++;
1433         clnt->cl_stats->rpccnt++;
1434         task->tk_action = call_reserve;
1435 }
1436
1437 /*
1438  * 1.   Reserve an RPC call slot
1439  */
1440 static void
1441 call_reserve(struct rpc_task *task)
1442 {
1443         dprint_status(task);
1444
1445         task->tk_status  = 0;
1446         task->tk_action  = call_reserveresult;
1447         xprt_reserve(task);
1448 }
1449
1450 static void call_retry_reserve(struct rpc_task *task);
1451
1452 /*
1453  * 1b.  Grok the result of xprt_reserve()
1454  */
1455 static void
1456 call_reserveresult(struct rpc_task *task)
1457 {
1458         int status = task->tk_status;
1459
1460         dprint_status(task);
1461
1462         /*
1463          * After a call to xprt_reserve(), we must have either
1464          * a request slot or else an error status.
1465          */
1466         task->tk_status = 0;
1467         if (status >= 0) {
1468                 if (task->tk_rqstp) {
1469                         task->tk_action = call_refresh;
1470                         return;
1471                 }
1472
1473                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1474                                 __func__, status);
1475                 rpc_exit(task, -EIO);
1476                 return;
1477         }
1478
1479         /*
1480          * Even though there was an error, we may have acquired
1481          * a request slot somehow.  Make sure not to leak it.
1482          */
1483         if (task->tk_rqstp) {
1484                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1485                                 __func__, status);
1486                 xprt_release(task);
1487         }
1488
1489         switch (status) {
1490         case -ENOMEM:
1491                 rpc_delay(task, HZ >> 2);
1492         case -EAGAIN:   /* woken up; retry */
1493                 task->tk_action = call_retry_reserve;
1494                 return;
1495         case -EIO:      /* probably a shutdown */
1496                 break;
1497         default:
1498                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1499                                 __func__, status);
1500                 break;
1501         }
1502         rpc_exit(task, status);
1503 }
1504
1505 /*
1506  * 1c.  Retry reserving an RPC call slot
1507  */
1508 static void
1509 call_retry_reserve(struct rpc_task *task)
1510 {
1511         dprint_status(task);
1512
1513         task->tk_status  = 0;
1514         task->tk_action  = call_reserveresult;
1515         xprt_retry_reserve(task);
1516 }
1517
1518 /*
1519  * 2.   Bind and/or refresh the credentials
1520  */
1521 static void
1522 call_refresh(struct rpc_task *task)
1523 {
1524         dprint_status(task);
1525
1526         task->tk_action = call_refreshresult;
1527         task->tk_status = 0;
1528         task->tk_client->cl_stats->rpcauthrefresh++;
1529         rpcauth_refreshcred(task);
1530 }
1531
1532 /*
1533  * 2a.  Process the results of a credential refresh
1534  */
1535 static void
1536 call_refreshresult(struct rpc_task *task)
1537 {
1538         int status = task->tk_status;
1539
1540         dprint_status(task);
1541
1542         task->tk_status = 0;
1543         task->tk_action = call_refresh;
1544         switch (status) {
1545         case 0:
1546                 if (rpcauth_uptodatecred(task)) {
1547                         task->tk_action = call_allocate;
1548                         return;
1549                 }
1550                 /* Use rate-limiting and a max number of retries if refresh
1551                  * had status 0 but failed to update the cred.
1552                  */
1553         case -ETIMEDOUT:
1554                 rpc_delay(task, 3*HZ);
1555         case -EAGAIN:
1556                 status = -EACCES;
1557         case -EKEYEXPIRED:
1558                 if (!task->tk_cred_retry)
1559                         break;
1560                 task->tk_cred_retry--;
1561                 dprintk("RPC: %5u %s: retry refresh creds\n",
1562                                 task->tk_pid, __func__);
1563                 return;
1564         }
1565         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1566                                 task->tk_pid, __func__, status);
1567         rpc_exit(task, status);
1568 }
1569
1570 /*
1571  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1572  *      (Note: buffer memory is freed in xprt_release).
1573  */
1574 static void
1575 call_allocate(struct rpc_task *task)
1576 {
1577         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1578         struct rpc_rqst *req = task->tk_rqstp;
1579         struct rpc_xprt *xprt = req->rq_xprt;
1580         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1581
1582         dprint_status(task);
1583
1584         task->tk_status = 0;
1585         task->tk_action = call_bind;
1586
1587         if (req->rq_buffer)
1588                 return;
1589
1590         if (proc->p_proc != 0) {
1591                 BUG_ON(proc->p_arglen == 0);
1592                 if (proc->p_decode != NULL)
1593                         BUG_ON(proc->p_replen == 0);
1594         }
1595
1596         /*
1597          * Calculate the size (in quads) of the RPC call
1598          * and reply headers, and convert both values
1599          * to byte sizes.
1600          */
1601         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1602         req->rq_callsize <<= 2;
1603         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1604         req->rq_rcvsize <<= 2;
1605
1606         req->rq_buffer = xprt->ops->buf_alloc(task,
1607                                         req->rq_callsize + req->rq_rcvsize);
1608         if (req->rq_buffer != NULL)
1609                 return;
1610         xprt_inject_disconnect(xprt);
1611
1612         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1613
1614         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1615                 task->tk_action = call_allocate;
1616                 rpc_delay(task, HZ>>4);
1617                 return;
1618         }
1619
1620         rpc_exit(task, -ERESTARTSYS);
1621 }
1622
1623 static inline int
1624 rpc_task_need_encode(struct rpc_task *task)
1625 {
1626         return task->tk_rqstp->rq_snd_buf.len == 0;
1627 }
1628
1629 static inline void
1630 rpc_task_force_reencode(struct rpc_task *task)
1631 {
1632         task->tk_rqstp->rq_snd_buf.len = 0;
1633         task->tk_rqstp->rq_bytes_sent = 0;
1634 }
1635
1636 static inline void
1637 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1638 {
1639         buf->head[0].iov_base = start;
1640         buf->head[0].iov_len = len;
1641         buf->tail[0].iov_len = 0;
1642         buf->page_len = 0;
1643         buf->flags = 0;
1644         buf->len = 0;
1645         buf->buflen = len;
1646 }
1647
1648 /*
1649  * 3.   Encode arguments of an RPC call
1650  */
1651 static void
1652 rpc_xdr_encode(struct rpc_task *task)
1653 {
1654         struct rpc_rqst *req = task->tk_rqstp;
1655         kxdreproc_t     encode;
1656         __be32          *p;
1657
1658         dprint_status(task);
1659
1660         rpc_xdr_buf_init(&req->rq_snd_buf,
1661                          req->rq_buffer,
1662                          req->rq_callsize);
1663         rpc_xdr_buf_init(&req->rq_rcv_buf,
1664                          (char *)req->rq_buffer + req->rq_callsize,
1665                          req->rq_rcvsize);
1666
1667         p = rpc_encode_header(task);
1668         if (p == NULL) {
1669                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1670                 rpc_exit(task, -EIO);
1671                 return;
1672         }
1673
1674         encode = task->tk_msg.rpc_proc->p_encode;
1675         if (encode == NULL)
1676                 return;
1677
1678         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1679                         task->tk_msg.rpc_argp);
1680 }
1681
1682 /*
1683  * 4.   Get the server port number if not yet set
1684  */
1685 static void
1686 call_bind(struct rpc_task *task)
1687 {
1688         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1689
1690         dprint_status(task);
1691
1692         task->tk_action = call_connect;
1693         if (!xprt_bound(xprt)) {
1694                 task->tk_action = call_bind_status;
1695                 task->tk_timeout = xprt->bind_timeout;
1696                 xprt->ops->rpcbind(task);
1697         }
1698 }
1699
1700 /*
1701  * 4a.  Sort out bind result
1702  */
1703 static void
1704 call_bind_status(struct rpc_task *task)
1705 {
1706         int status = -EIO;
1707
1708         if (task->tk_status >= 0) {
1709                 dprint_status(task);
1710                 task->tk_status = 0;
1711                 task->tk_action = call_connect;
1712                 return;
1713         }
1714
1715         trace_rpc_bind_status(task);
1716         switch (task->tk_status) {
1717         case -ENOMEM:
1718                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1719                 rpc_delay(task, HZ >> 2);
1720                 goto retry_timeout;
1721         case -EACCES:
1722                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1723                                 "unavailable\n", task->tk_pid);
1724                 /* fail immediately if this is an RPC ping */
1725                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1726                         status = -EOPNOTSUPP;
1727                         break;
1728                 }
1729                 if (task->tk_rebind_retry == 0)
1730                         break;
1731                 task->tk_rebind_retry--;
1732                 rpc_delay(task, 3*HZ);
1733                 goto retry_timeout;
1734         case -ETIMEDOUT:
1735                 dprintk("RPC: %5u rpcbind request timed out\n",
1736                                 task->tk_pid);
1737                 goto retry_timeout;
1738         case -EPFNOSUPPORT:
1739                 /* server doesn't support any rpcbind version we know of */
1740                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1741                                 task->tk_pid);
1742                 break;
1743         case -EPROTONOSUPPORT:
1744                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1745                                 task->tk_pid);
1746                 goto retry_timeout;
1747         case -ECONNREFUSED:             /* connection problems */
1748         case -ECONNRESET:
1749         case -ECONNABORTED:
1750         case -ENOTCONN:
1751         case -EHOSTDOWN:
1752         case -EHOSTUNREACH:
1753         case -ENETUNREACH:
1754         case -ENOBUFS:
1755         case -EPIPE:
1756                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1757                                 task->tk_pid, task->tk_status);
1758                 if (!RPC_IS_SOFTCONN(task)) {
1759                         rpc_delay(task, 5*HZ);
1760                         goto retry_timeout;
1761                 }
1762                 status = task->tk_status;
1763                 break;
1764         default:
1765                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1766                                 task->tk_pid, -task->tk_status);
1767         }
1768
1769         rpc_exit(task, status);
1770         return;
1771
1772 retry_timeout:
1773         task->tk_status = 0;
1774         task->tk_action = call_timeout;
1775 }
1776
1777 /*
1778  * 4b.  Connect to the RPC server
1779  */
1780 static void
1781 call_connect(struct rpc_task *task)
1782 {
1783         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1784
1785         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1786                         task->tk_pid, xprt,
1787                         (xprt_connected(xprt) ? "is" : "is not"));
1788
1789         task->tk_action = call_transmit;
1790         if (!xprt_connected(xprt)) {
1791                 task->tk_action = call_connect_status;
1792                 if (task->tk_status < 0)
1793                         return;
1794                 if (task->tk_flags & RPC_TASK_NOCONNECT) {
1795                         rpc_exit(task, -ENOTCONN);
1796                         return;
1797                 }
1798                 xprt_connect(task);
1799         }
1800 }
1801
1802 /*
1803  * 4c.  Sort out connect result
1804  */
1805 static void
1806 call_connect_status(struct rpc_task *task)
1807 {
1808         struct rpc_clnt *clnt = task->tk_client;
1809         int status = task->tk_status;
1810
1811         dprint_status(task);
1812
1813         trace_rpc_connect_status(task, status);
1814         task->tk_status = 0;
1815         switch (status) {
1816         case -ECONNREFUSED:
1817         case -ECONNRESET:
1818         case -ECONNABORTED:
1819         case -ENETUNREACH:
1820         case -EHOSTUNREACH:
1821         case -EADDRINUSE:
1822         case -ENOBUFS:
1823         case -EPIPE:
1824                 if (RPC_IS_SOFTCONN(task))
1825                         break;
1826                 /* retry with existing socket, after a delay */
1827                 rpc_delay(task, 3*HZ);
1828         case -EAGAIN:
1829                 /* Check for timeouts before looping back to call_bind */
1830         case -ETIMEDOUT:
1831                 task->tk_action = call_timeout;
1832                 return;
1833         case 0:
1834                 clnt->cl_stats->netreconn++;
1835                 task->tk_action = call_transmit;
1836                 return;
1837         }
1838         rpc_exit(task, status);
1839 }
1840
1841 /*
1842  * 5.   Transmit the RPC request, and wait for reply
1843  */
1844 static void
1845 call_transmit(struct rpc_task *task)
1846 {
1847         int is_retrans = RPC_WAS_SENT(task);
1848
1849         dprint_status(task);
1850
1851         task->tk_action = call_status;
1852         if (task->tk_status < 0)
1853                 return;
1854         if (!xprt_prepare_transmit(task))
1855                 return;
1856         task->tk_action = call_transmit_status;
1857         /* Encode here so that rpcsec_gss can use correct sequence number. */
1858         if (rpc_task_need_encode(task)) {
1859                 rpc_xdr_encode(task);
1860                 /* Did the encode result in an error condition? */
1861                 if (task->tk_status != 0) {
1862                         /* Was the error nonfatal? */
1863                         if (task->tk_status == -EAGAIN)
1864                                 rpc_delay(task, HZ >> 4);
1865                         else
1866                                 rpc_exit(task, task->tk_status);
1867                         return;
1868                 }
1869         }
1870         xprt_transmit(task);
1871         if (task->tk_status < 0)
1872                 return;
1873         if (is_retrans)
1874                 task->tk_client->cl_stats->rpcretrans++;
1875         /*
1876          * On success, ensure that we call xprt_end_transmit() before sleeping
1877          * in order to allow access to the socket to other RPC requests.
1878          */
1879         call_transmit_status(task);
1880         if (rpc_reply_expected(task))
1881                 return;
1882         task->tk_action = rpc_exit_task;
1883         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1884 }
1885
1886 /*
1887  * 5a.  Handle cleanup after a transmission
1888  */
1889 static void
1890 call_transmit_status(struct rpc_task *task)
1891 {
1892         task->tk_action = call_status;
1893
1894         /*
1895          * Common case: success.  Force the compiler to put this
1896          * test first.
1897          */
1898         if (task->tk_status == 0) {
1899                 xprt_end_transmit(task);
1900                 rpc_task_force_reencode(task);
1901                 return;
1902         }
1903
1904         switch (task->tk_status) {
1905         case -EAGAIN:
1906         case -ENOBUFS:
1907                 break;
1908         default:
1909                 dprint_status(task);
1910                 xprt_end_transmit(task);
1911                 rpc_task_force_reencode(task);
1912                 break;
1913                 /*
1914                  * Special cases: if we've been waiting on the
1915                  * socket's write_space() callback, or if the
1916                  * socket just returned a connection error,
1917                  * then hold onto the transport lock.
1918                  */
1919         case -ECONNREFUSED:
1920         case -EHOSTDOWN:
1921         case -EHOSTUNREACH:
1922         case -ENETUNREACH:
1923         case -EPERM:
1924                 if (RPC_IS_SOFTCONN(task)) {
1925                         xprt_end_transmit(task);
1926                         rpc_exit(task, task->tk_status);
1927                         break;
1928                 }
1929         case -ECONNRESET:
1930         case -ECONNABORTED:
1931         case -EADDRINUSE:
1932         case -ENOTCONN:
1933         case -EPIPE:
1934                 rpc_task_force_reencode(task);
1935         }
1936 }
1937
1938 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1939 /*
1940  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1941  * addition, disconnect on connectivity errors.
1942  */
1943 static void
1944 call_bc_transmit(struct rpc_task *task)
1945 {
1946         struct rpc_rqst *req = task->tk_rqstp;
1947
1948         if (!xprt_prepare_transmit(task))
1949                 goto out_retry;
1950
1951         if (task->tk_status < 0) {
1952                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1953                         "error: %d\n", task->tk_status);
1954                 goto out_done;
1955         }
1956         if (req->rq_connect_cookie != req->rq_xprt->connect_cookie)
1957                 req->rq_bytes_sent = 0;
1958
1959         xprt_transmit(task);
1960
1961         if (task->tk_status == -EAGAIN)
1962                 goto out_nospace;
1963
1964         xprt_end_transmit(task);
1965         dprint_status(task);
1966         switch (task->tk_status) {
1967         case 0:
1968                 /* Success */
1969         case -EHOSTDOWN:
1970         case -EHOSTUNREACH:
1971         case -ENETUNREACH:
1972         case -ECONNRESET:
1973         case -ECONNREFUSED:
1974         case -EADDRINUSE:
1975         case -ENOTCONN:
1976         case -EPIPE:
1977                 break;
1978         case -ETIMEDOUT:
1979                 /*
1980                  * Problem reaching the server.  Disconnect and let the
1981                  * forechannel reestablish the connection.  The server will
1982                  * have to retransmit the backchannel request and we'll
1983                  * reprocess it.  Since these ops are idempotent, there's no
1984                  * need to cache our reply at this time.
1985                  */
1986                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1987                         "error: %d\n", task->tk_status);
1988                 xprt_conditional_disconnect(req->rq_xprt,
1989                         req->rq_connect_cookie);
1990                 break;
1991         default:
1992                 /*
1993                  * We were unable to reply and will have to drop the
1994                  * request.  The server should reconnect and retransmit.
1995                  */
1996                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
1997                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1998                         "error: %d\n", task->tk_status);
1999                 break;
2000         }
2001         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
2002 out_done:
2003         task->tk_action = rpc_exit_task;
2004         return;
2005 out_nospace:
2006         req->rq_connect_cookie = req->rq_xprt->connect_cookie;
2007 out_retry:
2008         task->tk_status = 0;
2009 }
2010 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
2011
2012 /*
2013  * 6.   Sort out the RPC call status
2014  */
2015 static void
2016 call_status(struct rpc_task *task)
2017 {
2018         struct rpc_clnt *clnt = task->tk_client;
2019         struct rpc_rqst *req = task->tk_rqstp;
2020         int             status;
2021
2022         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
2023                 task->tk_status = req->rq_reply_bytes_recvd;
2024
2025         dprint_status(task);
2026
2027         status = task->tk_status;
2028         if (status >= 0) {
2029                 task->tk_action = call_decode;
2030                 return;
2031         }
2032
2033         trace_rpc_call_status(task);
2034         task->tk_status = 0;
2035         switch(status) {
2036         case -EHOSTDOWN:
2037         case -EHOSTUNREACH:
2038         case -ENETUNREACH:
2039         case -EPERM:
2040                 if (RPC_IS_SOFTCONN(task)) {
2041                         rpc_exit(task, status);
2042                         break;
2043                 }
2044                 /*
2045                  * Delay any retries for 3 seconds, then handle as if it
2046                  * were a timeout.
2047                  */
2048                 rpc_delay(task, 3*HZ);
2049         case -ETIMEDOUT:
2050                 task->tk_action = call_timeout;
2051                 if (!(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
2052                     && task->tk_client->cl_discrtry)
2053                         xprt_conditional_disconnect(req->rq_xprt,
2054                                         req->rq_connect_cookie);
2055                 break;
2056         case -ECONNREFUSED:
2057         case -ECONNRESET:
2058         case -ECONNABORTED:
2059                 rpc_force_rebind(clnt);
2060         case -EADDRINUSE:
2061                 rpc_delay(task, 3*HZ);
2062         case -EPIPE:
2063         case -ENOTCONN:
2064                 task->tk_action = call_bind;
2065                 break;
2066         case -ENOBUFS:
2067                 rpc_delay(task, HZ>>2);
2068         case -EAGAIN:
2069                 task->tk_action = call_transmit;
2070                 break;
2071         case -EIO:
2072                 /* shutdown or soft timeout */
2073                 rpc_exit(task, status);
2074                 break;
2075         default:
2076                 if (clnt->cl_chatty)
2077                         printk("%s: RPC call returned error %d\n",
2078                                clnt->cl_program->name, -status);
2079                 rpc_exit(task, status);
2080         }
2081 }
2082
2083 /*
2084  * 6a.  Handle RPC timeout
2085  *      We do not release the request slot, so we keep using the
2086  *      same XID for all retransmits.
2087  */
2088 static void
2089 call_timeout(struct rpc_task *task)
2090 {
2091         struct rpc_clnt *clnt = task->tk_client;
2092
2093         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
2094                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
2095                 goto retry;
2096         }
2097
2098         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
2099         task->tk_timeouts++;
2100
2101         if (RPC_IS_SOFTCONN(task)) {
2102                 rpc_exit(task, -ETIMEDOUT);
2103                 return;
2104         }
2105         if (RPC_IS_SOFT(task)) {
2106                 if (clnt->cl_chatty) {
2107                         rcu_read_lock();
2108                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
2109                                 clnt->cl_program->name,
2110                                 rcu_dereference(clnt->cl_xprt)->servername);
2111                         rcu_read_unlock();
2112                 }
2113                 if (task->tk_flags & RPC_TASK_TIMEOUT)
2114                         rpc_exit(task, -ETIMEDOUT);
2115                 else
2116                         rpc_exit(task, -EIO);
2117                 return;
2118         }
2119
2120         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2121                 task->tk_flags |= RPC_CALL_MAJORSEEN;
2122                 if (clnt->cl_chatty) {
2123                         rcu_read_lock();
2124                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
2125                         clnt->cl_program->name,
2126                         rcu_dereference(clnt->cl_xprt)->servername);
2127                         rcu_read_unlock();
2128                 }
2129         }
2130         rpc_force_rebind(clnt);
2131         /*
2132          * Did our request time out due to an RPCSEC_GSS out-of-sequence
2133          * event? RFC2203 requires the server to drop all such requests.
2134          */
2135         rpcauth_invalcred(task);
2136
2137 retry:
2138         task->tk_action = call_bind;
2139         task->tk_status = 0;
2140 }
2141
2142 /*
2143  * 7.   Decode the RPC reply
2144  */
2145 static void
2146 call_decode(struct rpc_task *task)
2147 {
2148         struct rpc_clnt *clnt = task->tk_client;
2149         struct rpc_rqst *req = task->tk_rqstp;
2150         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
2151         __be32          *p;
2152
2153         dprint_status(task);
2154
2155         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2156                 if (clnt->cl_chatty) {
2157                         rcu_read_lock();
2158                         printk(KERN_NOTICE "%s: server %s OK\n",
2159                                 clnt->cl_program->name,
2160                                 rcu_dereference(clnt->cl_xprt)->servername);
2161                         rcu_read_unlock();
2162                 }
2163                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2164         }
2165
2166         /*
2167          * Ensure that we see all writes made by xprt_complete_rqst()
2168          * before it changed req->rq_reply_bytes_recvd.
2169          */
2170         smp_rmb();
2171         req->rq_rcv_buf.len = req->rq_private_buf.len;
2172
2173         /* Check that the softirq receive buffer is valid */
2174         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2175                                 sizeof(req->rq_rcv_buf)) != 0);
2176
2177         if (req->rq_rcv_buf.len < 12) {
2178                 if (!RPC_IS_SOFT(task)) {
2179                         task->tk_action = call_bind;
2180                         goto out_retry;
2181                 }
2182                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2183                                 clnt->cl_program->name, task->tk_status);
2184                 task->tk_action = call_timeout;
2185                 goto out_retry;
2186         }
2187
2188         p = rpc_verify_header(task);
2189         if (IS_ERR(p)) {
2190                 if (p == ERR_PTR(-EAGAIN))
2191                         goto out_retry;
2192                 return;
2193         }
2194
2195         task->tk_action = rpc_exit_task;
2196
2197         if (decode) {
2198                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2199                                                       task->tk_msg.rpc_resp);
2200         }
2201         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2202                         task->tk_status);
2203         return;
2204 out_retry:
2205         task->tk_status = 0;
2206         /* Note: rpc_verify_header() may have freed the RPC slot */
2207         if (task->tk_rqstp == req) {
2208                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2209                 if (task->tk_client->cl_discrtry)
2210                         xprt_conditional_disconnect(req->rq_xprt,
2211                                         req->rq_connect_cookie);
2212         }
2213 }
2214
2215 static __be32 *
2216 rpc_encode_header(struct rpc_task *task)
2217 {
2218         struct rpc_clnt *clnt = task->tk_client;
2219         struct rpc_rqst *req = task->tk_rqstp;
2220         __be32          *p = req->rq_svec[0].iov_base;
2221
2222         /* FIXME: check buffer size? */
2223
2224         p = xprt_skip_transport_header(req->rq_xprt, p);
2225         *p++ = req->rq_xid;             /* XID */
2226         *p++ = htonl(RPC_CALL);         /* CALL */
2227         *p++ = htonl(RPC_VERSION);      /* RPC version */
2228         *p++ = htonl(clnt->cl_prog);    /* program number */
2229         *p++ = htonl(clnt->cl_vers);    /* program version */
2230         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2231         p = rpcauth_marshcred(task, p);
2232         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2233         return p;
2234 }
2235
2236 static __be32 *
2237 rpc_verify_header(struct rpc_task *task)
2238 {
2239         struct rpc_clnt *clnt = task->tk_client;
2240         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2241         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2242         __be32  *p = iov->iov_base;
2243         u32 n;
2244         int error = -EACCES;
2245
2246         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2247                 /* RFC-1014 says that the representation of XDR data must be a
2248                  * multiple of four bytes
2249                  * - if it isn't pointer subtraction in the NFS client may give
2250                  *   undefined results
2251                  */
2252                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2253                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2254                        task->tk_rqstp->rq_rcv_buf.len);
2255                 error = -EIO;
2256                 goto out_err;
2257         }
2258         if ((len -= 3) < 0)
2259                 goto out_overflow;
2260
2261         p += 1; /* skip XID */
2262         if ((n = ntohl(*p++)) != RPC_REPLY) {
2263                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2264                         task->tk_pid, __func__, n);
2265                 error = -EIO;
2266                 goto out_garbage;
2267         }
2268
2269         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2270                 if (--len < 0)
2271                         goto out_overflow;
2272                 switch ((n = ntohl(*p++))) {
2273                 case RPC_AUTH_ERROR:
2274                         break;
2275                 case RPC_MISMATCH:
2276                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2277                                 task->tk_pid, __func__);
2278                         error = -EPROTONOSUPPORT;
2279                         goto out_err;
2280                 default:
2281                         dprintk("RPC: %5u %s: RPC call rejected, "
2282                                 "unknown error: %x\n",
2283                                 task->tk_pid, __func__, n);
2284                         error = -EIO;
2285                         goto out_err;
2286                 }
2287                 if (--len < 0)
2288                         goto out_overflow;
2289                 switch ((n = ntohl(*p++))) {
2290                 case RPC_AUTH_REJECTEDCRED:
2291                 case RPC_AUTH_REJECTEDVERF:
2292                 case RPCSEC_GSS_CREDPROBLEM:
2293                 case RPCSEC_GSS_CTXPROBLEM:
2294                         if (!task->tk_cred_retry)
2295                                 break;
2296                         task->tk_cred_retry--;
2297                         dprintk("RPC: %5u %s: retry stale creds\n",
2298                                         task->tk_pid, __func__);
2299                         rpcauth_invalcred(task);
2300                         /* Ensure we obtain a new XID! */
2301                         xprt_release(task);
2302                         task->tk_action = call_reserve;
2303                         goto out_retry;
2304                 case RPC_AUTH_BADCRED:
2305                 case RPC_AUTH_BADVERF:
2306                         /* possibly garbled cred/verf? */
2307                         if (!task->tk_garb_retry)
2308                                 break;
2309                         task->tk_garb_retry--;
2310                         dprintk("RPC: %5u %s: retry garbled creds\n",
2311                                         task->tk_pid, __func__);
2312                         task->tk_action = call_bind;
2313                         goto out_retry;
2314                 case RPC_AUTH_TOOWEAK:
2315                         rcu_read_lock();
2316                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2317                                "authentication.\n",
2318                                rcu_dereference(clnt->cl_xprt)->servername);
2319                         rcu_read_unlock();
2320                         break;
2321                 default:
2322                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2323                                         task->tk_pid, __func__, n);
2324                         error = -EIO;
2325                 }
2326                 dprintk("RPC: %5u %s: call rejected %d\n",
2327                                 task->tk_pid, __func__, n);
2328                 goto out_err;
2329         }
2330         p = rpcauth_checkverf(task, p);
2331         if (IS_ERR(p)) {
2332                 error = PTR_ERR(p);
2333                 dprintk("RPC: %5u %s: auth check failed with %d\n",
2334                                 task->tk_pid, __func__, error);
2335                 goto out_garbage;               /* bad verifier, retry */
2336         }
2337         len = p - (__be32 *)iov->iov_base - 1;
2338         if (len < 0)
2339                 goto out_overflow;
2340         switch ((n = ntohl(*p++))) {
2341         case RPC_SUCCESS:
2342                 return p;
2343         case RPC_PROG_UNAVAIL:
2344                 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2345                                 "by server %s\n", task->tk_pid, __func__,
2346                                 (unsigned int)clnt->cl_prog,
2347                                 rcu_dereference(clnt->cl_xprt)->servername);
2348                 error = -EPFNOSUPPORT;
2349                 goto out_err;
2350         case RPC_PROG_MISMATCH:
2351                 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2352                                 "by server %s\n", task->tk_pid, __func__,
2353                                 (unsigned int)clnt->cl_prog,
2354                                 (unsigned int)clnt->cl_vers,
2355                                 rcu_dereference(clnt->cl_xprt)->servername);
2356                 error = -EPROTONOSUPPORT;
2357                 goto out_err;
2358         case RPC_PROC_UNAVAIL:
2359                 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2360                                 "version %u on server %s\n",
2361                                 task->tk_pid, __func__,
2362                                 rpc_proc_name(task),
2363                                 clnt->cl_prog, clnt->cl_vers,
2364                                 rcu_dereference(clnt->cl_xprt)->servername);
2365                 error = -EOPNOTSUPP;
2366                 goto out_err;
2367         case RPC_GARBAGE_ARGS:
2368                 dprintk("RPC: %5u %s: server saw garbage\n",
2369                                 task->tk_pid, __func__);
2370                 break;                  /* retry */
2371         default:
2372                 dprintk("RPC: %5u %s: server accept status: %x\n",
2373                                 task->tk_pid, __func__, n);
2374                 /* Also retry */
2375         }
2376
2377 out_garbage:
2378         clnt->cl_stats->rpcgarbage++;
2379         if (task->tk_garb_retry) {
2380                 task->tk_garb_retry--;
2381                 dprintk("RPC: %5u %s: retrying\n",
2382                                 task->tk_pid, __func__);
2383                 task->tk_action = call_bind;
2384 out_retry:
2385                 return ERR_PTR(-EAGAIN);
2386         }
2387 out_err:
2388         rpc_exit(task, error);
2389         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2390                         __func__, error);
2391         return ERR_PTR(error);
2392 out_overflow:
2393         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2394                         __func__);
2395         goto out_garbage;
2396 }
2397
2398 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2399 {
2400 }
2401
2402 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2403 {
2404         return 0;
2405 }
2406
2407 static struct rpc_procinfo rpcproc_null = {
2408         .p_encode = rpcproc_encode_null,
2409         .p_decode = rpcproc_decode_null,
2410 };
2411
2412 static int rpc_ping(struct rpc_clnt *clnt)
2413 {
2414         struct rpc_message msg = {
2415                 .rpc_proc = &rpcproc_null,
2416         };
2417         int err;
2418         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2419         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2420         put_rpccred(msg.rpc_cred);
2421         return err;
2422 }
2423
2424 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2425 {
2426         struct rpc_message msg = {
2427                 .rpc_proc = &rpcproc_null,
2428                 .rpc_cred = cred,
2429         };
2430         struct rpc_task_setup task_setup_data = {
2431                 .rpc_client = clnt,
2432                 .rpc_message = &msg,
2433                 .callback_ops = &rpc_default_ops,
2434                 .flags = flags,
2435         };
2436         return rpc_run_task(&task_setup_data);
2437 }
2438 EXPORT_SYMBOL_GPL(rpc_call_null);
2439
2440 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
2441 static void rpc_show_header(void)
2442 {
2443         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2444                 "-timeout ---ops--\n");
2445 }
2446
2447 static void rpc_show_task(const struct rpc_clnt *clnt,
2448                           const struct rpc_task *task)
2449 {
2450         const char *rpc_waitq = "none";
2451
2452         if (RPC_IS_QUEUED(task))
2453                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2454
2455         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2456                 task->tk_pid, task->tk_flags, task->tk_status,
2457                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2458                 clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
2459                 task->tk_action, rpc_waitq);
2460 }
2461
2462 void rpc_show_tasks(struct net *net)
2463 {
2464         struct rpc_clnt *clnt;
2465         struct rpc_task *task;
2466         int header = 0;
2467         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2468
2469         spin_lock(&sn->rpc_client_lock);
2470         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2471                 spin_lock(&clnt->cl_lock);
2472                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2473                         if (!header) {
2474                                 rpc_show_header();
2475                                 header++;
2476                         }
2477                         rpc_show_task(clnt, task);
2478                 }
2479                 spin_unlock(&clnt->cl_lock);
2480         }
2481         spin_unlock(&sn->rpc_client_lock);
2482 }
2483 #endif
2484
2485 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
2486 int
2487 rpc_clnt_swap_activate(struct rpc_clnt *clnt)
2488 {
2489         int ret = 0;
2490         struct rpc_xprt *xprt;
2491
2492         if (atomic_inc_return(&clnt->cl_swapper) == 1) {
2493 retry:
2494                 rcu_read_lock();
2495                 xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
2496                 rcu_read_unlock();
2497                 if (!xprt) {
2498                         /*
2499                          * If we didn't get a reference, then we likely are
2500                          * racing with a migration event. Wait for a grace
2501                          * period and try again.
2502                          */
2503                         synchronize_rcu();
2504                         goto retry;
2505                 }
2506
2507                 ret = xprt_enable_swap(xprt);
2508                 xprt_put(xprt);
2509         }
2510         return ret;
2511 }
2512 EXPORT_SYMBOL_GPL(rpc_clnt_swap_activate);
2513
2514 void
2515 rpc_clnt_swap_deactivate(struct rpc_clnt *clnt)
2516 {
2517         struct rpc_xprt *xprt;
2518
2519         if (atomic_dec_if_positive(&clnt->cl_swapper) == 0) {
2520 retry:
2521                 rcu_read_lock();
2522                 xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
2523                 rcu_read_unlock();
2524                 if (!xprt) {
2525                         /*
2526                          * If we didn't get a reference, then we likely are
2527                          * racing with a migration event. Wait for a grace
2528                          * period and try again.
2529                          */
2530                         synchronize_rcu();
2531                         goto retry;
2532                 }
2533
2534                 xprt_disable_swap(xprt);
2535                 xprt_put(xprt);
2536         }
2537 }
2538 EXPORT_SYMBOL_GPL(rpc_clnt_swap_deactivate);
2539 #endif /* CONFIG_SUNRPC_SWAP */