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   1 /*
   2  *  linux/fs/nfsd/nfs4callback.c
   3  *
   4  *  Copyright (c) 2001 The Regents of the University of Michigan.
   5  *  All rights reserved.
   6  *
   7  *  Kendrick Smith <kmsmith@umich.edu>
   8  *  Andy Adamson <andros@umich.edu>
   9  *
  10  *  Redistribution and use in source and binary forms, with or without
  11  *  modification, are permitted provided that the following conditions
  12  *  are met:
  13  *
  14  *  1. Redistributions of source code must retain the above copyright
  15  *     notice, this list of conditions and the following disclaimer.
  16  *  2. Redistributions in binary form must reproduce the above copyright
  17  *     notice, this list of conditions and the following disclaimer in the
  18  *     documentation and/or other materials provided with the distribution.
  19  *  3. Neither the name of the University nor the names of its
  20  *     contributors may be used to endorse or promote products derived
  21  *     from this software without specific prior written permission.
  22  *
  23  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  24  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  25  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  26  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  28  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  29  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  30  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 #include <linux/module.h>
  37 #include <linux/list.h>
  38 #include <linux/inet.h>
  39 #include <linux/errno.h>
  40 #include <linux/delay.h>
  41 #include <linux/sched.h>
  42 #include <linux/kthread.h>
  43 #include <linux/sunrpc/xdr.h>
  44 #include <linux/sunrpc/svc.h>
  45 #include <linux/sunrpc/clnt.h>
  46 #include <linux/sunrpc/svcsock.h>
  47 #include <linux/nfsd/nfsd.h>
  48 #include <linux/nfsd/state.h>
  49 #include <linux/sunrpc/sched.h>
  50 #include <linux/nfs4.h>
  51
  52 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  53
  54 #define NFSPROC4_CB_NULL 0
  55 #define NFSPROC4_CB_COMPOUND 1
  56 #define NFS4_STATEID_SIZE 16
  57
  58 /* Index of predefined Linux callback client operations */
  59
  60 enum {
  61         NFSPROC4_CLNT_CB_NULL = 0,
  62         NFSPROC4_CLNT_CB_RECALL,
  63         NFSPROC4_CLNT_CB_SEQUENCE,
  64 };
  65
  66 enum nfs_cb_opnum4 {
  67         OP_CB_RECALL            = 4,
  68         OP_CB_SEQUENCE          = 11,
  69 };
  70
  71 #define NFS4_MAXTAGLEN          20
  72
  73 #define NFS4_enc_cb_null_sz             0
  74 #define NFS4_dec_cb_null_sz             0
  75 #define cb_compound_enc_hdr_sz          4
  76 #define cb_compound_dec_hdr_sz          (3 + (NFS4_MAXTAGLEN >> 2))
  77 #define sessionid_sz                    (NFS4_MAX_SESSIONID_LEN >> 2)
  78 #define cb_sequence_enc_sz              (sessionid_sz + 4 +             \
  79                                         1 /* no referring calls list yet */)
  80 #define cb_sequence_dec_sz              (op_dec_sz + sessionid_sz + 4)
  81
  82 #define op_enc_sz                       1
  83 #define op_dec_sz                       2
  84 #define enc_nfs4_fh_sz                  (1 + (NFS4_FHSIZE >> 2))
  85 #define enc_stateid_sz                  (NFS4_STATEID_SIZE >> 2)
  86 #define NFS4_enc_cb_recall_sz           (cb_compound_enc_hdr_sz +       \
  87                                         cb_sequence_enc_sz +            \
  88                                         1 + enc_stateid_sz +            \
  89                                         enc_nfs4_fh_sz)
  90
  91 #define NFS4_dec_cb_recall_sz           (cb_compound_dec_hdr_sz  +      \
  92                                         cb_sequence_dec_sz +            \
  93                                         op_dec_sz)
  94
  95 struct nfs4_rpc_args {
  96         void                            *args_op;
  97         struct nfsd4_cb_sequence        args_seq;
  98 };
  99
 100 /*
 101 * Generic encode routines from fs/nfs/nfs4xdr.c
 102 */
 103 static inline __be32 *
 104 xdr_writemem(__be32 *p, const void *ptr, int nbytes)
 105 {
 106         int tmp = XDR_QUADLEN(nbytes);
 107         if (!tmp)
 108                 return p;
 109         p[tmp-1] = 0;
 110         memcpy(p, ptr, nbytes);
 111         return p + tmp;
 112 }
 113
 114 #define WRITE32(n)               *p++ = htonl(n)
 115 #define WRITEMEM(ptr,nbytes)     do {                           \
 116         p = xdr_writemem(p, ptr, nbytes);                       \
 117 } while (0)
 118 #define RESERVE_SPACE(nbytes)   do {                            \
 119         p = xdr_reserve_space(xdr, nbytes);                     \
 120         if (!p) dprintk("NFSD: RESERVE_SPACE(%d) failed in function %s\n", (int) (nbytes), __func__); \
 121         BUG_ON(!p);                                             \
 122 } while (0)
 123
 124 /*
 125  * Generic decode routines from fs/nfs/nfs4xdr.c
 126  */
 127 #define DECODE_TAIL                             \
 128         status = 0;                             \
 129 out:                                            \
 130         return status;                          \
 131 xdr_error:                                      \
 132         dprintk("NFSD: xdr error! (%s:%d)\n", __FILE__, __LINE__); \
 133         status = -EIO;                          \
 134         goto out
 135
 136 #define READ32(x)         (x) = ntohl(*p++)
 137 #define READ64(x)         do {                  \
 138         (x) = (u64)ntohl(*p++) << 32;           \
 139         (x) |= ntohl(*p++);                     \
 140 } while (0)
 141 #define READTIME(x)       do {                  \
 142         p++;                                    \
 143         (x.tv_sec) = ntohl(*p++);               \
 144         (x.tv_nsec) = ntohl(*p++);              \
 145 } while (0)
 146 #define READ_BUF(nbytes)  do { \
 147         p = xdr_inline_decode(xdr, nbytes); \
 148         if (!p) { \
 149                 dprintk("NFSD: %s: reply buffer overflowed in line %d.\n", \
 150                         __func__, __LINE__); \
 151                 return -EIO; \
 152         } \
 153 } while (0)
 154
 155 struct nfs4_cb_compound_hdr {
 156         /* args */
 157         u32             ident;  /* minorversion 0 only */
 158         u32             nops;
 159         __be32          *nops_p;
 160         u32             minorversion;
 161         /* res */
 162         int             status;
 163         u32             taglen;
 164         char            *tag;
 165 };
 166
 167 static struct {
 168 int stat;
 169 int errno;
 170 } nfs_cb_errtbl[] = {
 171         { NFS4_OK,              0               },
 172         { NFS4ERR_PERM,         EPERM           },
 173         { NFS4ERR_NOENT,        ENOENT          },
 174         { NFS4ERR_IO,           EIO             },
 175         { NFS4ERR_NXIO,         ENXIO           },
 176         { NFS4ERR_ACCESS,       EACCES          },
 177         { NFS4ERR_EXIST,        EEXIST          },
 178         { NFS4ERR_XDEV,         EXDEV           },
 179         { NFS4ERR_NOTDIR,       ENOTDIR         },
 180         { NFS4ERR_ISDIR,        EISDIR          },
 181         { NFS4ERR_INVAL,        EINVAL          },
 182         { NFS4ERR_FBIG,         EFBIG           },
 183         { NFS4ERR_NOSPC,        ENOSPC          },
 184         { NFS4ERR_ROFS,         EROFS           },
 185         { NFS4ERR_MLINK,        EMLINK          },
 186         { NFS4ERR_NAMETOOLONG,  ENAMETOOLONG    },
 187         { NFS4ERR_NOTEMPTY,     ENOTEMPTY       },
 188         { NFS4ERR_DQUOT,        EDQUOT          },
 189         { NFS4ERR_STALE,        ESTALE          },
 190         { NFS4ERR_BADHANDLE,    EBADHANDLE      },
 191         { NFS4ERR_BAD_COOKIE,   EBADCOOKIE      },
 192         { NFS4ERR_NOTSUPP,      ENOTSUPP        },
 193         { NFS4ERR_TOOSMALL,     ETOOSMALL       },
 194         { NFS4ERR_SERVERFAULT,  ESERVERFAULT    },
 195         { NFS4ERR_BADTYPE,      EBADTYPE        },
 196         { NFS4ERR_LOCKED,       EAGAIN          },
 197         { NFS4ERR_RESOURCE,     EREMOTEIO       },
 198         { NFS4ERR_SYMLINK,      ELOOP           },
 199         { NFS4ERR_OP_ILLEGAL,   EOPNOTSUPP      },
 200         { NFS4ERR_DEADLOCK,     EDEADLK         },
 201         { -1,                   EIO             }
 202 };
 203
 204 static int
 205 nfs_cb_stat_to_errno(int stat)
 206 {
 207         int i;
 208         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 209                 if (nfs_cb_errtbl[i].stat == stat)
 210                         return nfs_cb_errtbl[i].errno;
 211         }
 212         /* If we cannot translate the error, the recovery routines should
 213         * handle it.
 214         * Note: remaining NFSv4 error codes have values > 10000, so should
 215         * not conflict with native Linux error codes.
 216         */
 217         return stat;
 218 }
 219
 220 /*
 221  * XDR encode
 222  */
 223
 224 static void
 225 encode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr)
 226 {
 227         __be32 * p;
 228
 229         RESERVE_SPACE(16);
 230         WRITE32(0);            /* tag length is always 0 */
 231         WRITE32(hdr->minorversion);
 232         WRITE32(hdr->ident);
 233         hdr->nops_p = p;
 234         WRITE32(hdr->nops);
 235 }
 236
 237 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 238 {
 239         *hdr->nops_p = htonl(hdr->nops);
 240 }
 241
 242 static void
 243 encode_cb_recall(struct xdr_stream *xdr, struct nfs4_delegation *dp,
 244                 struct nfs4_cb_compound_hdr *hdr)
 245 {
 246         __be32 *p;
 247         int len = dp->dl_fh.fh_size;
 248
 249         RESERVE_SPACE(12+sizeof(dp->dl_stateid) + len);
 250         WRITE32(OP_CB_RECALL);
 251         WRITE32(dp->dl_stateid.si_generation);
 252         WRITEMEM(&dp->dl_stateid.si_opaque, sizeof(stateid_opaque_t));
 253         WRITE32(0); /* truncate optimization not implemented */
 254         WRITE32(len);
 255         WRITEMEM(&dp->dl_fh.fh_base, len);
 256         hdr->nops++;
 257 }
 258
 259 static int
 260 nfs4_xdr_enc_cb_null(struct rpc_rqst *req, __be32 *p)
 261 {
 262         struct xdr_stream xdrs, *xdr = &xdrs;
 263
 264         xdr_init_encode(&xdrs, &req->rq_snd_buf, p);
 265         RESERVE_SPACE(0);
 266         return 0;
 267 }
 268
 269 static int
 270 nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p, struct nfs4_delegation *args)
 271 {
 272         struct xdr_stream xdr;
 273         struct nfs4_cb_compound_hdr hdr = {
 274                 .ident = args->dl_ident,
 275         };
 276
 277         xdr_init_encode(&xdr, &req->rq_snd_buf, p);
 278         encode_cb_compound_hdr(&xdr, &hdr);
 279         encode_cb_recall(&xdr, args, &hdr);
 280         encode_cb_nops(&hdr);
 281         return 0;
 282 }
 283
 284
 285 static int
 286 decode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr){
 287         __be32 *p;
 288
 289         READ_BUF(8);
 290         READ32(hdr->status);
 291         READ32(hdr->taglen);
 292         READ_BUF(hdr->taglen + 4);
 293         hdr->tag = (char *)p;
 294         p += XDR_QUADLEN(hdr->taglen);
 295         READ32(hdr->nops);
 296         return 0;
 297 }
 298
 299 static int
 300 decode_cb_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
 301 {
 302         __be32 *p;
 303         u32 op;
 304         int32_t nfserr;
 305
 306         READ_BUF(8);
 307         READ32(op);
 308         if (op != expected) {
 309                 dprintk("NFSD: decode_cb_op_hdr: Callback server returned "
 310                          " operation %d but we issued a request for %d\n",
 311                          op, expected);
 312                 return -EIO;
 313         }
 314         READ32(nfserr);
 315         if (nfserr != NFS_OK)
 316                 return -nfs_cb_stat_to_errno(nfserr);
 317         return 0;
 318 }
 319
 320 static int
 321 nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
 322 {
 323         return 0;
 324 }
 325
 326 static int
 327 nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp, __be32 *p)
 328 {
 329         struct xdr_stream xdr;
 330         struct nfs4_cb_compound_hdr hdr;
 331         int status;
 332
 333         xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
 334         status = decode_cb_compound_hdr(&xdr, &hdr);
 335         if (status)
 336                 goto out;
 337         status = decode_cb_op_hdr(&xdr, OP_CB_RECALL);
 338 out:
 339         return status;
 340 }
 341
 342 /*
 343  * RPC procedure tables
 344  */
 345 #define PROC(proc, call, argtype, restype)                              \
 346 [NFSPROC4_CLNT_##proc] = {                                              \
 347         .p_proc   = NFSPROC4_CB_##call,                                 \
 348         .p_encode = (kxdrproc_t) nfs4_xdr_##argtype,                    \
 349         .p_decode = (kxdrproc_t) nfs4_xdr_##restype,                    \
 350         .p_arglen = NFS4_##argtype##_sz,                                \
 351         .p_replen = NFS4_##restype##_sz,                                \
 352         .p_statidx = NFSPROC4_CB_##call,                                \
 353         .p_name   = #proc,                                              \
 354 }
 355
 356 static struct rpc_procinfo     nfs4_cb_procedures[] = {
 357     PROC(CB_NULL,      NULL,     enc_cb_null,     dec_cb_null),
 358     PROC(CB_RECALL,    COMPOUND,   enc_cb_recall,      dec_cb_recall),
 359 };
 360
 361 static struct rpc_version       nfs_cb_version4 = {
 362         .number                 = 1,
 363         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 364         .procs                  = nfs4_cb_procedures
 365 };
 366
 367 static struct rpc_version *     nfs_cb_version[] = {
 368         NULL,
 369         &nfs_cb_version4,
 370 };
 371
 372 static struct rpc_program cb_program;
 373
 374 static struct rpc_stat cb_stats = {
 375                 .program        = &cb_program
 376 };
 377
 378 #define NFS4_CALLBACK 0x40000000
 379 static struct rpc_program cb_program = {
 380                 .name           = "nfs4_cb",
 381                 .number         = NFS4_CALLBACK,
 382                 .nrvers         = ARRAY_SIZE(nfs_cb_version),
 383                 .version        = nfs_cb_version,
 384                 .stats          = &cb_stats,
 385                 .pipe_dir_name  = "/nfsd4_cb",
 386 };
 387
 388 static int max_cb_time(void)
 389 {
 390         return max(NFSD_LEASE_TIME/10, (time_t)1) * HZ;
 391 }
 392
 393 /* Reference counting, callback cleanup, etc., all look racy as heck.
 394  * And why is cb_set an atomic? */
 395
 396 int setup_callback_client(struct nfs4_client *clp)
 397 {
 398         struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
 399         struct rpc_timeout      timeparms = {
 400                 .to_initval     = max_cb_time(),
 401                 .to_retries     = 0,
 402         };
 403         struct rpc_create_args args = {
 404                 .protocol       = IPPROTO_TCP,
 405                 .address        = (struct sockaddr *) &cb->cb_addr,
 406                 .addrsize       = cb->cb_addrlen,
 407                 .timeout        = &timeparms,
 408                 .program        = &cb_program,
 409                 .prognumber     = cb->cb_prog,
 410                 .version        = nfs_cb_version[1]->number,
 411                 .authflavor     = clp->cl_flavor,
 412                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 413                 .client_name    = clp->cl_principal,
 414         };
 415         struct rpc_clnt *client;
 416
 417         if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
 418                 return -EINVAL;
 419
 420         /* Create RPC client */
 421         client = rpc_create(&args);
 422         if (IS_ERR(client)) {
 423                 dprintk("NFSD: couldn't create callback client: %ld\n",
 424                         PTR_ERR(client));
 425                 return PTR_ERR(client);
 426         }
 427         cb->cb_client = client;
 428         return 0;
 429
 430 }
 431
 432 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 433 {
 434         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 435                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 436 }
 437
 438 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 439 {
 440         struct nfs4_client *clp = calldata;
 441
 442         if (task->tk_status)
 443                 warn_no_callback_path(clp, task->tk_status);
 444         else
 445                 atomic_set(&clp->cl_cb_conn.cb_set, 1);
 446         put_nfs4_client(clp);
 447 }
 448
 449 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 450         .rpc_call_done = nfsd4_cb_probe_done,
 451 };
 452
 453 static struct rpc_cred *callback_cred;
 454
 455 int set_callback_cred(void)
 456 {
 457         callback_cred = rpc_lookup_machine_cred();
 458         if (!callback_cred)
 459                 return -ENOMEM;
 460         return 0;
 461 }
 462
 463
 464 void do_probe_callback(struct nfs4_client *clp)
 465 {
 466         struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
 467         struct rpc_message msg = {
 468                 .rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
 469                 .rpc_argp       = clp,
 470                 .rpc_cred       = callback_cred
 471         };
 472         int status;
 473
 474         status = rpc_call_async(cb->cb_client, &msg, RPC_TASK_SOFT,
 475                                 &nfsd4_cb_probe_ops, (void *)clp);
 476         if (status) {
 477                 warn_no_callback_path(clp, status);
 478                 put_nfs4_client(clp);
 479         }
 480 }
 481
 482 /*
 483  * Set up the callback client and put a NFSPROC4_CB_NULL on the wire...
 484  */
 485 void
 486 nfsd4_probe_callback(struct nfs4_client *clp)
 487 {
 488         int status;
 489
 490         BUG_ON(atomic_read(&clp->cl_cb_conn.cb_set));
 491
 492         status = setup_callback_client(clp);
 493         if (status) {
 494                 warn_no_callback_path(clp, status);
 495                 return;
 496         }
 497
 498         /* the task holds a reference to the nfs4_client struct */
 499         atomic_inc(&clp->cl_count);
 500
 501         do_probe_callback(clp);
 502 }
 503
 504 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 505 {
 506         struct nfs4_delegation *dp = calldata;
 507         struct nfs4_client *clp = dp->dl_client;
 508
 509         switch (task->tk_status) {
 510         case -EIO:
 511                 /* Network partition? */
 512                 atomic_set(&clp->cl_cb_conn.cb_set, 0);
 513                 warn_no_callback_path(clp, task->tk_status);
 514         case -EBADHANDLE:
 515         case -NFS4ERR_BAD_STATEID:
 516                 /* Race: client probably got cb_recall
 517                  * before open reply granting delegation */
 518                 break;
 519         default:
 520                 /* success, or error we can't handle */
 521                 return;
 522         }
 523         if (dp->dl_retries--) {
 524                 rpc_delay(task, 2*HZ);
 525                 task->tk_status = 0;
 526                 rpc_restart_call(task);
 527         } else {
 528                 atomic_set(&clp->cl_cb_conn.cb_set, 0);
 529                 warn_no_callback_path(clp, task->tk_status);
 530         }
 531 }
 532
 533 static void nfsd4_cb_recall_release(void *calldata)
 534 {
 535         struct nfs4_delegation *dp = calldata;
 536         struct nfs4_client *clp = dp->dl_client;
 537
 538         nfs4_put_delegation(dp);
 539         put_nfs4_client(clp);
 540 }
 541
 542 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
 543         .rpc_call_done = nfsd4_cb_recall_done,
 544         .rpc_release = nfsd4_cb_recall_release,
 545 };
 546
 547 /*
 548  * called with dp->dl_count inc'ed.
 549  */
 550 void
 551 nfsd4_cb_recall(struct nfs4_delegation *dp)
 552 {
 553         struct nfs4_client *clp = dp->dl_client;
 554         struct rpc_clnt *clnt = clp->cl_cb_conn.cb_client;
 555         struct rpc_message msg = {
 556                 .rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL],
 557                 .rpc_argp = dp,
 558                 .rpc_cred = callback_cred
 559         };
 560         int status;
 561
 562         dp->dl_retries = 1;
 563         status = rpc_call_async(clnt, &msg, RPC_TASK_SOFT,
 564                                 &nfsd4_cb_recall_ops, dp);
 565         if (status) {
 566                 put_nfs4_client(clp);
 567                 nfs4_put_delegation(dp);
 568         }
 569 }