fs/lockd/clntxdr.c

   1 /*
   2  * linux/fs/lockd/clntxdr.c
   3  *
   4  * XDR functions to encode/decode NLM version 3 RPC arguments and results.
   5  * NLM version 3 is backwards compatible with NLM versions 1 and 2.
   6  *
   7  * NLM client-side only.
   8  *
   9  * Copyright (C) 2010, Oracle.  All rights reserved.
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/sunrpc/xdr.h>
  14 #include <linux/sunrpc/clnt.h>
  15 #include <linux/sunrpc/stats.h>
  16 #include <linux/lockd/lockd.h>
  17
  18 #define NLMDBG_FACILITY         NLMDBG_XDR
  19
  20 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
  21 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
  22 #endif
  23
  24 /*
  25  * Declare the space requirements for NLM arguments and replies as
  26  * number of 32bit-words
  27  */
  28 #define NLM_cookie_sz           (1+(NLM_MAXCOOKIELEN>>2))
  29 #define NLM_caller_sz           (1+(NLMCLNT_OHSIZE>>2))
  30 #define NLM_owner_sz            (1+(NLMCLNT_OHSIZE>>2))
  31 #define NLM_fhandle_sz          (1+(NFS2_FHSIZE>>2))
  32 #define NLM_lock_sz             (3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
  33 #define NLM_holder_sz           (4+NLM_owner_sz)
  34
  35 #define NLM_testargs_sz         (NLM_cookie_sz+1+NLM_lock_sz)
  36 #define NLM_lockargs_sz         (NLM_cookie_sz+4+NLM_lock_sz)
  37 #define NLM_cancargs_sz         (NLM_cookie_sz+2+NLM_lock_sz)
  38 #define NLM_unlockargs_sz       (NLM_cookie_sz+NLM_lock_sz)
  39
  40 #define NLM_testres_sz          (NLM_cookie_sz+1+NLM_holder_sz)
  41 #define NLM_res_sz              (NLM_cookie_sz+1)
  42 #define NLM_norep_sz            (0)
  43
  44
  45 static s32 loff_t_to_s32(loff_t offset)
  46 {
  47         s32 res;
  48
  49         if (offset >= NLM_OFFSET_MAX)
  50                 res = NLM_OFFSET_MAX;
  51         else if (offset <= -NLM_OFFSET_MAX)
  52                 res = -NLM_OFFSET_MAX;
  53         else
  54                 res = offset;
  55         return res;
  56 }
  57
  58 static void nlm_compute_offsets(const struct nlm_lock *lock,
  59                                 u32 *l_offset, u32 *l_len)
  60 {
  61         const struct file_lock *fl = &lock->fl;
  62
  63         BUG_ON(fl->fl_start > NLM_OFFSET_MAX);
  64         BUG_ON(fl->fl_end > NLM_OFFSET_MAX &&
  65                                 fl->fl_end != OFFSET_MAX);
  66
  67         *l_offset = loff_t_to_s32(fl->fl_start);
  68         if (fl->fl_end == OFFSET_MAX)
  69                 *l_len = 0;
  70         else
  71                 *l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
  72 }
  73
  74 /*
  75  * Handle decode buffer overflows out-of-line.
  76  */
  77 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  78 {
  79         dprintk("lockd: %s prematurely hit the end of our receive buffer. "
  80                 "Remaining buffer length is %tu words.\n",
  81                 func, xdr->end - xdr->p);
  82 }
  83
  84
  85 /*
  86  * Encode/decode NLMv3 basic data types
  87  *
  88  * Basic NLMv3 data types are not defined in an IETF standards
  89  * document.  X/Open has a description of these data types that
  90  * is useful.  See Chapter 10 of "Protocols for Interworking:
  91  * XNFS, Version 3W".
  92  *
  93  * Not all basic data types have their own encoding and decoding
  94  * functions.  For run-time efficiency, some data types are encoded
  95  * or decoded inline.
  96  */
  97
  98 static void encode_bool(struct xdr_stream *xdr, const int value)
  99 {
 100         __be32 *p;
 101
 102         p = xdr_reserve_space(xdr, 4);
 103         *p = value ? xdr_one : xdr_zero;
 104 }
 105
 106 static void encode_int32(struct xdr_stream *xdr, const s32 value)
 107 {
 108         __be32 *p;
 109
 110         p = xdr_reserve_space(xdr, 4);
 111         *p = cpu_to_be32(value);
 112 }
 113
 114 /*
 115  *      typedef opaque netobj<MAXNETOBJ_SZ>
 116  */
 117 static void encode_netobj(struct xdr_stream *xdr,
 118                           const u8 *data, const unsigned int length)
 119 {
 120         __be32 *p;
 121
 122         BUG_ON(length > XDR_MAX_NETOBJ);
 123         p = xdr_reserve_space(xdr, 4 + length);
 124         xdr_encode_opaque(p, data, length);
 125 }
 126
 127 static int decode_netobj(struct xdr_stream *xdr,
 128                          struct xdr_netobj *obj)
 129 {
 130         u32 length;
 131         __be32 *p;
 132
 133         p = xdr_inline_decode(xdr, 4);
 134         if (unlikely(p == NULL))
 135                 goto out_overflow;
 136         length = be32_to_cpup(p++);
 137         if (unlikely(length > XDR_MAX_NETOBJ))
 138                 goto out_size;
 139         obj->len = length;
 140         obj->data = (u8 *)p;
 141         return 0;
 142 out_size:
 143         dprintk("NFS: returned netobj was too long: %u\n", length);
 144         return -EIO;
 145 out_overflow:
 146         print_overflow_msg(__func__, xdr);
 147         return -EIO;
 148 }
 149
 150 /*
 151  *      netobj cookie;
 152  */
 153 static void encode_cookie(struct xdr_stream *xdr,
 154                           const struct nlm_cookie *cookie)
 155 {
 156         BUG_ON(cookie->len > NLM_MAXCOOKIELEN);
 157         encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
 158 }
 159
 160 static int decode_cookie(struct xdr_stream *xdr,
 161                          struct nlm_cookie *cookie)
 162 {
 163         u32 length;
 164         __be32 *p;
 165
 166         p = xdr_inline_decode(xdr, 4);
 167         if (unlikely(p == NULL))
 168                 goto out_overflow;
 169         length = be32_to_cpup(p++);
 170         /* apparently HPUX can return empty cookies */
 171         if (length == 0)
 172                 goto out_hpux;
 173         if (length > NLM_MAXCOOKIELEN)
 174                 goto out_size;
 175         p = xdr_inline_decode(xdr, length);
 176         if (unlikely(p == NULL))
 177                 goto out_overflow;
 178         cookie->len = length;
 179         memcpy(cookie->data, p, length);
 180         return 0;
 181 out_hpux:
 182         cookie->len = 4;
 183         memset(cookie->data, 0, 4);
 184         return 0;
 185 out_size:
 186         dprintk("NFS: returned cookie was too long: %u\n", length);
 187         return -EIO;
 188 out_overflow:
 189         print_overflow_msg(__func__, xdr);
 190         return -EIO;
 191 }
 192
 193 /*
 194  *      netobj fh;
 195  */
 196 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
 197 {
 198         BUG_ON(fh->size != NFS2_FHSIZE);
 199         encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
 200 }
 201
 202 /*
 203  *      enum nlm_stats {
 204  *              LCK_GRANTED = 0,
 205  *              LCK_DENIED = 1,
 206  *              LCK_DENIED_NOLOCKS = 2,
 207  *              LCK_BLOCKED = 3,
 208  *              LCK_DENIED_GRACE_PERIOD = 4
 209  *      };
 210  *
 211  *
 212  *      struct nlm_stat {
 213  *              nlm_stats stat;
 214  *      };
 215  *
 216  * NB: we don't swap bytes for the NLM status values.  The upper
 217  * layers deal directly with the status value in network byte
 218  * order.
 219  */
 220
 221 static void encode_nlm_stat(struct xdr_stream *xdr,
 222                             const __be32 stat)
 223 {
 224         __be32 *p;
 225
 226         BUG_ON(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
 227         p = xdr_reserve_space(xdr, 4);
 228         *p = stat;
 229 }
 230
 231 static int decode_nlm_stat(struct xdr_stream *xdr,
 232                            __be32 *stat)
 233 {
 234         __be32 *p;
 235
 236         p = xdr_inline_decode(xdr, 4);
 237         if (unlikely(p == NULL))
 238                 goto out_overflow;
 239         if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
 240                 goto out_enum;
 241         *stat = *p;
 242         return 0;
 243 out_enum:
 244         dprintk("%s: server returned invalid nlm_stats value: %u\n",
 245                 __func__, be32_to_cpup(p));
 246         return -EIO;
 247 out_overflow:
 248         print_overflow_msg(__func__, xdr);
 249         return -EIO;
 250 }
 251
 252 /*
 253  *      struct nlm_holder {
 254  *              bool exclusive;
 255  *              int uppid;
 256  *              netobj oh;
 257  *              unsigned l_offset;
 258  *              unsigned l_len;
 259  *      };
 260  */
 261 static void encode_nlm_holder(struct xdr_stream *xdr,
 262                               const struct nlm_res *result)
 263 {
 264         const struct nlm_lock *lock = &result->lock;
 265         u32 l_offset, l_len;
 266         __be32 *p;
 267
 268         encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
 269         encode_int32(xdr, lock->svid);
 270         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 271
 272         p = xdr_reserve_space(xdr, 4 + 4);
 273         nlm_compute_offsets(lock, &l_offset, &l_len);
 274         *p++ = cpu_to_be32(l_offset);
 275         *p   = cpu_to_be32(l_len);
 276 }
 277
 278 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
 279 {
 280         struct nlm_lock *lock = &result->lock;
 281         struct file_lock *fl = &lock->fl;
 282         u32 exclusive, l_offset, l_len;
 283         int error;
 284         __be32 *p;
 285         s32 end;
 286
 287         memset(lock, 0, sizeof(*lock));
 288         locks_init_lock(fl);
 289
 290         p = xdr_inline_decode(xdr, 4 + 4);
 291         if (unlikely(p == NULL))
 292                 goto out_overflow;
 293         exclusive = be32_to_cpup(p++);
 294         lock->svid = be32_to_cpup(p);
 295         fl->fl_pid = (pid_t)lock->svid;
 296
 297         error = decode_netobj(xdr, &lock->oh);
 298         if (unlikely(error))
 299                 goto out;
 300
 301         p = xdr_inline_decode(xdr, 4 + 4);
 302         if (unlikely(p == NULL))
 303                 goto out_overflow;
 304
 305         fl->fl_flags = FL_POSIX;
 306         fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
 307         l_offset = be32_to_cpup(p++);
 308         l_len = be32_to_cpup(p);
 309         end = l_offset + l_len - 1;
 310
 311         fl->fl_start = (loff_t)l_offset;
 312         if (l_len == 0 || end < 0)
 313                 fl->fl_end = OFFSET_MAX;
 314         else
 315                 fl->fl_end = (loff_t)end;
 316         error = 0;
 317 out:
 318         return error;
 319 out_overflow:
 320         print_overflow_msg(__func__, xdr);
 321         return -EIO;
 322 }
 323
 324 /*
 325  *      string caller_name<LM_MAXSTRLEN>;
 326  */
 327 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
 328 {
 329         /* NB: client-side does not set lock->len */
 330         u32 length = strlen(name);
 331         __be32 *p;
 332
 333         BUG_ON(length > NLM_MAXSTRLEN);
 334         p = xdr_reserve_space(xdr, 4 + length);
 335         xdr_encode_opaque(p, name, length);
 336 }
 337
 338 /*
 339  *      struct nlm_lock {
 340  *              string caller_name<LM_MAXSTRLEN>;
 341  *              netobj fh;
 342  *              netobj oh;
 343  *              int uppid;
 344  *              unsigned l_offset;
 345  *              unsigned l_len;
 346  *      };
 347  */
 348 static void encode_nlm_lock(struct xdr_stream *xdr,
 349                             const struct nlm_lock *lock)
 350 {
 351         u32 l_offset, l_len;
 352         __be32 *p;
 353
 354         encode_caller_name(xdr, lock->caller);
 355         encode_fh(xdr, &lock->fh);
 356         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 357
 358         p = xdr_reserve_space(xdr, 4 + 4 + 4);
 359         *p++ = cpu_to_be32(lock->svid);
 360
 361         nlm_compute_offsets(lock, &l_offset, &l_len);
 362         *p++ = cpu_to_be32(l_offset);
 363         *p   = cpu_to_be32(l_len);
 364 }
 365
 366
 367 /*
 368  * NLMv3 XDR encode functions
 369  *
 370  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
 371  * "Protocols for Interworking: XNFS, Version 3W".
 372  */
 373
 374 /*
 375  *      struct nlm_testargs {
 376  *              netobj cookie;
 377  *              bool exclusive;
 378  *              struct nlm_lock alock;
 379  *      };
 380  */
 381 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
 382                                  struct xdr_stream *xdr,
 383                                  const struct nlm_args *args)
 384 {
 385         const struct nlm_lock *lock = &args->lock;
 386
 387         encode_cookie(xdr, &args->cookie);
 388         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 389         encode_nlm_lock(xdr, lock);
 390 }
 391
 392 /*
 393  *      struct nlm_lockargs {
 394  *              netobj cookie;
 395  *              bool block;
 396  *              bool exclusive;
 397  *              struct nlm_lock alock;
 398  *              bool reclaim;
 399  *              int state;
 400  *      };
 401  */
 402 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
 403                                  struct xdr_stream *xdr,
 404                                  const struct nlm_args *args)
 405 {
 406         const struct nlm_lock *lock = &args->lock;
 407
 408         encode_cookie(xdr, &args->cookie);
 409         encode_bool(xdr, args->block);
 410         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 411         encode_nlm_lock(xdr, lock);
 412         encode_bool(xdr, args->reclaim);
 413         encode_int32(xdr, args->state);
 414 }
 415
 416 /*
 417  *      struct nlm_cancargs {
 418  *              netobj cookie;
 419  *              bool block;
 420  *              bool exclusive;
 421  *              struct nlm_lock alock;
 422  *      };
 423  */
 424 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
 425                                  struct xdr_stream *xdr,
 426                                  const struct nlm_args *args)
 427 {
 428         const struct nlm_lock *lock = &args->lock;
 429
 430         encode_cookie(xdr, &args->cookie);
 431         encode_bool(xdr, args->block);
 432         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 433         encode_nlm_lock(xdr, lock);
 434 }
 435
 436 /*
 437  *      struct nlm_unlockargs {
 438  *              netobj cookie;
 439  *              struct nlm_lock alock;
 440  *      };
 441  */
 442 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
 443                                    struct xdr_stream *xdr,
 444                                    const struct nlm_args *args)
 445 {
 446         const struct nlm_lock *lock = &args->lock;
 447
 448         encode_cookie(xdr, &args->cookie);
 449         encode_nlm_lock(xdr, lock);
 450 }
 451
 452 /*
 453  *      struct nlm_res {
 454  *              netobj cookie;
 455  *              nlm_stat stat;
 456  *      };
 457  */
 458 static void nlm_xdr_enc_res(struct rpc_rqst *req,
 459                             struct xdr_stream *xdr,
 460                             const struct nlm_res *result)
 461 {
 462         encode_cookie(xdr, &result->cookie);
 463         encode_nlm_stat(xdr, result->status);
 464 }
 465
 466 /*
 467  *      union nlm_testrply switch (nlm_stats stat) {
 468  *      case LCK_DENIED:
 469  *              struct nlm_holder holder;
 470  *      default:
 471  *              void;
 472  *      };
 473  *
 474  *      struct nlm_testres {
 475  *              netobj cookie;
 476  *              nlm_testrply test_stat;
 477  *      };
 478  */
 479 static void encode_nlm_testrply(struct xdr_stream *xdr,
 480                                 const struct nlm_res *result)
 481 {
 482         if (result->status == nlm_lck_denied)
 483                 encode_nlm_holder(xdr, result);
 484 }
 485
 486 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
 487                                 struct xdr_stream *xdr,
 488                                 const struct nlm_res *result)
 489 {
 490         encode_cookie(xdr, &result->cookie);
 491         encode_nlm_stat(xdr, result->status);
 492         encode_nlm_testrply(xdr, result);
 493 }
 494
 495
 496 /*
 497  * NLMv3 XDR decode functions
 498  *
 499  * NLMv3 result types are defined in Chapter 10 of The Open Group's
 500  * "Protocols for Interworking: XNFS, Version 3W".
 501  */
 502
 503 /*
 504  *      union nlm_testrply switch (nlm_stats stat) {
 505  *      case LCK_DENIED:
 506  *              struct nlm_holder holder;
 507  *      default:
 508  *              void;
 509  *      };
 510  *
 511  *      struct nlm_testres {
 512  *              netobj cookie;
 513  *              nlm_testrply test_stat;
 514  *      };
 515  */
 516 static int decode_nlm_testrply(struct xdr_stream *xdr,
 517                                struct nlm_res *result)
 518 {
 519         int error;
 520
 521         error = decode_nlm_stat(xdr, &result->status);
 522         if (unlikely(error))
 523                 goto out;
 524         if (result->status == nlm_lck_denied)
 525                 error = decode_nlm_holder(xdr, result);
 526 out:
 527         return error;
 528 }
 529
 530 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
 531                                struct xdr_stream *xdr,
 532                                struct nlm_res *result)
 533 {
 534         int error;
 535
 536         error = decode_cookie(xdr, &result->cookie);
 537         if (unlikely(error))
 538                 goto out;
 539         error = decode_nlm_testrply(xdr, result);
 540 out:
 541         return error;
 542 }
 543
 544 /*
 545  *      struct nlm_res {
 546  *              netobj cookie;
 547  *              nlm_stat stat;
 548  *      };
 549  */
 550 static int nlm_xdr_dec_res(struct rpc_rqst *req,
 551                            struct xdr_stream *xdr,
 552                            struct nlm_res *result)
 553 {
 554         int error;
 555
 556         error = decode_cookie(xdr, &result->cookie);
 557         if (unlikely(error))
 558                 goto out;
 559         error = decode_nlm_stat(xdr, &result->status);
 560 out:
 561         return error;
 562 }
 563
 564
 565 /*
 566  * For NLM, a void procedure really returns nothing
 567  */
 568 #define nlm_xdr_dec_norep       NULL
 569
 570 #define PROC(proc, argtype, restype)    \
 571 [NLMPROC_##proc] = {                                                    \
 572         .p_proc      = NLMPROC_##proc,                                  \
 573         .p_encode    = (kxdreproc_t)nlm_xdr_enc_##argtype,              \
 574         .p_decode    = (kxdrdproc_t)nlm_xdr_dec_##restype,              \
 575         .p_arglen    = NLM_##argtype##_sz,                              \
 576         .p_replen    = NLM_##restype##_sz,                              \
 577         .p_statidx   = NLMPROC_##proc,                                  \
 578         .p_name      = #proc,                                           \
 579         }
 580
 581 static struct rpc_procinfo      nlm_procedures[] = {
 582         PROC(TEST,              testargs,       testres),
 583         PROC(LOCK,              lockargs,       res),
 584         PROC(CANCEL,            cancargs,       res),
 585         PROC(UNLOCK,            unlockargs,     res),
 586         PROC(GRANTED,           testargs,       res),
 587         PROC(TEST_MSG,          testargs,       norep),
 588         PROC(LOCK_MSG,          lockargs,       norep),
 589         PROC(CANCEL_MSG,        cancargs,       norep),
 590         PROC(UNLOCK_MSG,        unlockargs,     norep),
 591         PROC(GRANTED_MSG,       testargs,       norep),
 592         PROC(TEST_RES,          testres,        norep),
 593         PROC(LOCK_RES,          res,            norep),
 594         PROC(CANCEL_RES,        res,            norep),
 595         PROC(UNLOCK_RES,        res,            norep),
 596         PROC(GRANTED_RES,       res,            norep),
 597 };
 598
 599 static struct rpc_version       nlm_version1 = {
 600                 .number         = 1,
 601                 .nrprocs        = ARRAY_SIZE(nlm_procedures),
 602                 .procs          = nlm_procedures,
 603 };
 604
 605 static struct rpc_version       nlm_version3 = {
 606                 .number         = 3,
 607                 .nrprocs        = ARRAY_SIZE(nlm_procedures),
 608                 .procs          = nlm_procedures,
 609 };
 610
 611 static struct rpc_version       *nlm_versions[] = {
 612         [1] = &nlm_version1,
 613         [3] = &nlm_version3,
 614 #ifdef CONFIG_LOCKD_V4
 615         [4] = &nlm_version4,
 616 #endif
 617 };
 618
 619 static struct rpc_stat          nlm_rpc_stats;
 620
 621 struct rpc_program              nlm_program = {
 622                 .name           = "lockd",
 623                 .number         = NLM_PROGRAM,
 624                 .nrvers         = ARRAY_SIZE(nlm_versions),
 625                 .version        = nlm_versions,
 626                 .stats          = &nlm_rpc_stats,
 627 };