fs/nfsd/nfs4callback.c

   1 /*
   2  *  Copyright (c) 2001 The Regents of the University of Michigan.
   3  *  All rights reserved.
   4  *
   5  *  Kendrick Smith <kmsmith@umich.edu>
   6  *  Andy Adamson <andros@umich.edu>
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions
  10  *  are met:
  11  *
  12  *  1. Redistributions of source code must retain the above copyright
  13  *     notice, this list of conditions and the following disclaimer.
  14  *  2. Redistributions in binary form must reproduce the above copyright
  15  *     notice, this list of conditions and the following disclaimer in the
  16  *     documentation and/or other materials provided with the distribution.
  17  *  3. Neither the name of the University nor the names of its
  18  *     contributors may be used to endorse or promote products derived
  19  *     from this software without specific prior written permission.
  20  *
  21  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  22  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  23  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  28  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  29  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  30  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  31  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/svc_xprt.h>
  36 #include <linux/slab.h>
  37 #include "nfsd.h"
  38 #include "state.h"
  39
  40 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  41
  42 #define NFSPROC4_CB_NULL 0
  43 #define NFSPROC4_CB_COMPOUND 1
  44
  45 /* Index of predefined Linux callback client operations */
  46
  47 enum {
  48         NFSPROC4_CLNT_CB_NULL = 0,
  49         NFSPROC4_CLNT_CB_RECALL,
  50         NFSPROC4_CLNT_CB_SEQUENCE,
  51 };
  52
  53 #define NFS4_MAXTAGLEN          20
  54
  55 #define NFS4_enc_cb_null_sz             0
  56 #define NFS4_dec_cb_null_sz             0
  57 #define cb_compound_enc_hdr_sz          4
  58 #define cb_compound_dec_hdr_sz          (3 + (NFS4_MAXTAGLEN >> 2))
  59 #define sessionid_sz                    (NFS4_MAX_SESSIONID_LEN >> 2)
  60 #define cb_sequence_enc_sz              (sessionid_sz + 4 +             \
  61                                         1 /* no referring calls list yet */)
  62 #define cb_sequence_dec_sz              (op_dec_sz + sessionid_sz + 4)
  63
  64 #define op_enc_sz                       1
  65 #define op_dec_sz                       2
  66 #define enc_nfs4_fh_sz                  (1 + (NFS4_FHSIZE >> 2))
  67 #define enc_stateid_sz                  (NFS4_STATEID_SIZE >> 2)
  68 #define NFS4_enc_cb_recall_sz           (cb_compound_enc_hdr_sz +       \
  69                                         cb_sequence_enc_sz +            \
  70                                         1 + enc_stateid_sz +            \
  71                                         enc_nfs4_fh_sz)
  72
  73 #define NFS4_dec_cb_recall_sz           (cb_compound_dec_hdr_sz  +      \
  74                                         cb_sequence_dec_sz +            \
  75                                         op_dec_sz)
  76
  77 struct nfs4_cb_compound_hdr {
  78         /* args */
  79         u32             ident;  /* minorversion 0 only */
  80         u32             nops;
  81         __be32          *nops_p;
  82         u32             minorversion;
  83         /* res */
  84         int             status;
  85 };
  86
  87 /*
  88  * Handle decode buffer overflows out-of-line.
  89  */
  90 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  91 {
  92         dprintk("NFS: %s prematurely hit the end of our receive buffer. "
  93                 "Remaining buffer length is %tu words.\n",
  94                 func, xdr->end - xdr->p);
  95 }
  96
  97 static __be32 *xdr_encode_empty_array(__be32 *p)
  98 {
  99         *p++ = xdr_zero;
 100         return p;
 101 }
 102
 103 /*
 104  * Encode/decode NFSv4 CB basic data types
 105  *
 106  * Basic NFSv4 callback data types are defined in section 15 of RFC
 107  * 3530: "Network File System (NFS) version 4 Protocol" and section
 108  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
 109  * 1 Protocol"
 110  */
 111
 112 /*
 113  *      nfs_cb_opnum4
 114  *
 115  *      enum nfs_cb_opnum4 {
 116  *              OP_CB_GETATTR           = 3,
 117  *                ...
 118  *      };
 119  */
 120 enum nfs_cb_opnum4 {
 121         OP_CB_GETATTR                   = 3,
 122         OP_CB_RECALL                    = 4,
 123         OP_CB_LAYOUTRECALL              = 5,
 124         OP_CB_NOTIFY                    = 6,
 125         OP_CB_PUSH_DELEG                = 7,
 126         OP_CB_RECALL_ANY                = 8,
 127         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
 128         OP_CB_RECALL_SLOT               = 10,
 129         OP_CB_SEQUENCE                  = 11,
 130         OP_CB_WANTS_CANCELLED           = 12,
 131         OP_CB_NOTIFY_LOCK               = 13,
 132         OP_CB_NOTIFY_DEVICEID           = 14,
 133         OP_CB_ILLEGAL                   = 10044
 134 };
 135
 136 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 137 {
 138         __be32 *p;
 139
 140         p = xdr_reserve_space(xdr, 4);
 141         *p = cpu_to_be32(op);
 142 }
 143
 144 /*
 145  * nfs_fh4
 146  *
 147  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 148  */
 149 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 150 {
 151         u32 length = fh->fh_size;
 152         __be32 *p;
 153
 154         BUG_ON(length > NFS4_FHSIZE);
 155         p = xdr_reserve_space(xdr, 4 + length);
 156         xdr_encode_opaque(p, &fh->fh_base, length);
 157 }
 158
 159 /*
 160  * stateid4
 161  *
 162  *      struct stateid4 {
 163  *              uint32_t        seqid;
 164  *              opaque          other[12];
 165  *      };
 166  */
 167 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 168 {
 169         __be32 *p;
 170
 171         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 172         *p++ = cpu_to_be32(sid->si_generation);
 173         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 174 }
 175
 176 /*
 177  * sessionid4
 178  *
 179  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 180  */
 181 static void encode_sessionid4(struct xdr_stream *xdr,
 182                               const struct nfsd4_session *session)
 183 {
 184         __be32 *p;
 185
 186         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 187         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 188                                         NFS4_MAX_SESSIONID_LEN);
 189 }
 190
 191 /*
 192  * nfsstat4
 193  */
 194 static const struct {
 195         int stat;
 196         int errno;
 197 } nfs_cb_errtbl[] = {
 198         { NFS4_OK,              0               },
 199         { NFS4ERR_PERM,         -EPERM          },
 200         { NFS4ERR_NOENT,        -ENOENT         },
 201         { NFS4ERR_IO,           -EIO            },
 202         { NFS4ERR_NXIO,         -ENXIO          },
 203         { NFS4ERR_ACCESS,       -EACCES         },
 204         { NFS4ERR_EXIST,        -EEXIST         },
 205         { NFS4ERR_XDEV,         -EXDEV          },
 206         { NFS4ERR_NOTDIR,       -ENOTDIR        },
 207         { NFS4ERR_ISDIR,        -EISDIR         },
 208         { NFS4ERR_INVAL,        -EINVAL         },
 209         { NFS4ERR_FBIG,         -EFBIG          },
 210         { NFS4ERR_NOSPC,        -ENOSPC         },
 211         { NFS4ERR_ROFS,         -EROFS          },
 212         { NFS4ERR_MLINK,        -EMLINK         },
 213         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 214         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 215         { NFS4ERR_DQUOT,        -EDQUOT         },
 216         { NFS4ERR_STALE,        -ESTALE         },
 217         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 218         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 219         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 220         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 221         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 222         { NFS4ERR_BADTYPE,      -EBADTYPE       },
 223         { NFS4ERR_LOCKED,       -EAGAIN         },
 224         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 225         { NFS4ERR_SYMLINK,      -ELOOP          },
 226         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 227         { NFS4ERR_DEADLOCK,     -EDEADLK        },
 228         { -1,                   -EIO            }
 229 };
 230
 231 /*
 232  * If we cannot translate the error, the recovery routines should
 233  * handle it.
 234  *
 235  * Note: remaining NFSv4 error codes have values > 10000, so should
 236  * not conflict with native Linux error codes.
 237  */
 238 static int nfs_cb_stat_to_errno(int status)
 239 {
 240         int i;
 241
 242         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 243                 if (nfs_cb_errtbl[i].stat == status)
 244                         return nfs_cb_errtbl[i].errno;
 245         }
 246
 247         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 248         return -status;
 249 }
 250
 251 static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
 252                                enum nfsstat4 *status)
 253 {
 254         __be32 *p;
 255         u32 op;
 256
 257         p = xdr_inline_decode(xdr, 4 + 4);
 258         if (unlikely(p == NULL))
 259                 goto out_overflow;
 260         op = be32_to_cpup(p++);
 261         if (unlikely(op != expected))
 262                 goto out_unexpected;
 263         *status = be32_to_cpup(p);
 264         return 0;
 265 out_overflow:
 266         print_overflow_msg(__func__, xdr);
 267         return -EIO;
 268 out_unexpected:
 269         dprintk("NFSD: Callback server returned operation %d but "
 270                 "we issued a request for %d\n", op, expected);
 271         return -EIO;
 272 }
 273
 274 /*
 275  * CB_COMPOUND4args
 276  *
 277  *      struct CB_COMPOUND4args {
 278  *              utf8str_cs      tag;
 279  *              uint32_t        minorversion;
 280  *              uint32_t        callback_ident;
 281  *              nfs_cb_argop4   argarray<>;
 282  *      };
 283 */
 284 static void encode_cb_compound4args(struct xdr_stream *xdr,
 285                                     struct nfs4_cb_compound_hdr *hdr)
 286 {
 287         __be32 * p;
 288
 289         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 290         p = xdr_encode_empty_array(p);          /* empty tag */
 291         *p++ = cpu_to_be32(hdr->minorversion);
 292         *p++ = cpu_to_be32(hdr->ident);
 293
 294         hdr->nops_p = p;
 295         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 296 }
 297
 298 /*
 299  * Update argarray element count
 300  */
 301 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 302 {
 303         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 304         *hdr->nops_p = cpu_to_be32(hdr->nops);
 305 }
 306
 307 /*
 308  * CB_COMPOUND4res
 309  *
 310  *      struct CB_COMPOUND4res {
 311  *              nfsstat4        status;
 312  *              utf8str_cs      tag;
 313  *              nfs_cb_resop4   resarray<>;
 314  *      };
 315  */
 316 static int decode_cb_compound4res(struct xdr_stream *xdr,
 317                                   struct nfs4_cb_compound_hdr *hdr)
 318 {
 319         u32 length;
 320         __be32 *p;
 321
 322         p = xdr_inline_decode(xdr, 4 + 4);
 323         if (unlikely(p == NULL))
 324                 goto out_overflow;
 325         hdr->status = be32_to_cpup(p++);
 326         /* Ignore the tag */
 327         length = be32_to_cpup(p++);
 328         p = xdr_inline_decode(xdr, length + 4);
 329         if (unlikely(p == NULL))
 330                 goto out_overflow;
 331         hdr->nops = be32_to_cpup(p);
 332         return 0;
 333 out_overflow:
 334         print_overflow_msg(__func__, xdr);
 335         return -EIO;
 336 }
 337
 338 /*
 339  * CB_RECALL4args
 340  *
 341  *      struct CB_RECALL4args {
 342  *              stateid4        stateid;
 343  *              bool            truncate;
 344  *              nfs_fh4         fh;
 345  *      };
 346  */
 347 static void encode_cb_recall4args(struct xdr_stream *xdr,
 348                                   const struct nfs4_delegation *dp,
 349                                   struct nfs4_cb_compound_hdr *hdr)
 350 {
 351         __be32 *p;
 352
 353         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 354         encode_stateid4(xdr, &dp->dl_stateid);
 355
 356         p = xdr_reserve_space(xdr, 4);
 357         *p++ = xdr_zero;                        /* truncate */
 358
 359         encode_nfs_fh4(xdr, &dp->dl_fh);
 360
 361         hdr->nops++;
 362 }
 363
 364 /*
 365  * CB_SEQUENCE4args
 366  *
 367  *      struct CB_SEQUENCE4args {
 368  *              sessionid4              csa_sessionid;
 369  *              sequenceid4             csa_sequenceid;
 370  *              slotid4                 csa_slotid;
 371  *              slotid4                 csa_highest_slotid;
 372  *              bool                    csa_cachethis;
 373  *              referring_call_list4    csa_referring_call_lists<>;
 374  *      };
 375  */
 376 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 377                                     const struct nfsd4_callback *cb,
 378                                     struct nfs4_cb_compound_hdr *hdr)
 379 {
 380         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 381         __be32 *p;
 382
 383         if (hdr->minorversion == 0)
 384                 return;
 385
 386         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 387         encode_sessionid4(xdr, session);
 388
 389         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 390         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 391         *p++ = xdr_zero;                        /* csa_slotid */
 392         *p++ = xdr_zero;                        /* csa_highest_slotid */
 393         *p++ = xdr_zero;                        /* csa_cachethis */
 394         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 395
 396         hdr->nops++;
 397 }
 398
 399 /*
 400  * CB_SEQUENCE4resok
 401  *
 402  *      struct CB_SEQUENCE4resok {
 403  *              sessionid4      csr_sessionid;
 404  *              sequenceid4     csr_sequenceid;
 405  *              slotid4         csr_slotid;
 406  *              slotid4         csr_highest_slotid;
 407  *              slotid4         csr_target_highest_slotid;
 408  *      };
 409  *
 410  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 411  *      case NFS4_OK:
 412  *              CB_SEQUENCE4resok       csr_resok4;
 413  *      default:
 414  *              void;
 415  *      };
 416  *
 417  * Our current back channel implmentation supports a single backchannel
 418  * with a single slot.
 419  */
 420 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 421                                     struct nfsd4_callback *cb)
 422 {
 423         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 424         struct nfs4_sessionid id;
 425         int status;
 426         __be32 *p;
 427         u32 dummy;
 428
 429         status = -ESERVERFAULT;
 430
 431         /*
 432          * If the server returns different values for sessionID, slotID or
 433          * sequence number, the server is looney tunes.
 434          */
 435         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4);
 436         if (unlikely(p == NULL))
 437                 goto out_overflow;
 438         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
 439         if (memcmp(id.data, session->se_sessionid.data,
 440                                         NFS4_MAX_SESSIONID_LEN) != 0) {
 441                 dprintk("NFS: %s Invalid session id\n", __func__);
 442                 goto out;
 443         }
 444         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 445
 446         dummy = be32_to_cpup(p++);
 447         if (dummy != session->se_cb_seq_nr) {
 448                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 449                 goto out;
 450         }
 451
 452         dummy = be32_to_cpup(p++);
 453         if (dummy != 0) {
 454                 dprintk("NFS: %s Invalid slotid\n", __func__);
 455                 goto out;
 456         }
 457
 458         /*
 459          * FIXME: process highest slotid and target highest slotid
 460          */
 461         status = 0;
 462 out:
 463         return status;
 464 out_overflow:
 465         print_overflow_msg(__func__, xdr);
 466         return -EIO;
 467 }
 468
 469 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 470                                   struct nfsd4_callback *cb)
 471 {
 472         enum nfsstat4 nfserr;
 473         int status;
 474
 475         if (cb->cb_minorversion == 0)
 476                 return 0;
 477
 478         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
 479         if (unlikely(status))
 480                 goto out;
 481         if (unlikely(nfserr != NFS4_OK))
 482                 goto out_default;
 483         status = decode_cb_sequence4resok(xdr, cb);
 484 out:
 485         return status;
 486 out_default:
 487         return nfs_cb_stat_to_errno(status);
 488 }
 489
 490 /*
 491  * NFSv4.0 and NFSv4.1 XDR encode functions
 492  *
 493  * NFSv4.0 callback argument types are defined in section 15 of RFC
 494  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 495  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 496  * Protocol".
 497  */
 498
 499 /*
 500  * NB: Without this zero space reservation, callbacks over krb5p fail
 501  */
 502 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 503                                  void *__unused)
 504 {
 505         xdr_reserve_space(xdr, 0);
 506 }
 507
 508 /*
 509  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 510  */
 511 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 512                                    const struct nfsd4_callback *cb)
 513 {
 514         const struct nfs4_delegation *args = cb->cb_op;
 515         struct nfs4_cb_compound_hdr hdr = {
 516                 .ident = cb->cb_clp->cl_cb_ident,
 517                 .minorversion = cb->cb_minorversion,
 518         };
 519
 520         encode_cb_compound4args(xdr, &hdr);
 521         encode_cb_sequence4args(xdr, cb, &hdr);
 522         encode_cb_recall4args(xdr, args, &hdr);
 523         encode_cb_nops(&hdr);
 524 }
 525
 526
 527 /*
 528  * NFSv4.0 and NFSv4.1 XDR decode functions
 529  *
 530  * NFSv4.0 callback result types are defined in section 15 of RFC
 531  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 532  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 533  * Protocol".
 534  */
 535
 536 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 537                                 void *__unused)
 538 {
 539         return 0;
 540 }
 541
 542 /*
 543  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 544  */
 545 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 546                                   struct xdr_stream *xdr,
 547                                   struct nfsd4_callback *cb)
 548 {
 549         struct nfs4_cb_compound_hdr hdr;
 550         enum nfsstat4 nfserr;
 551         int status;
 552
 553         status = decode_cb_compound4res(xdr, &hdr);
 554         if (unlikely(status))
 555                 goto out;
 556
 557         if (cb != NULL) {
 558                 status = decode_cb_sequence4res(xdr, cb);
 559                 if (unlikely(status))
 560                         goto out;
 561         }
 562
 563         status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
 564         if (unlikely(status))
 565                 goto out;
 566         if (unlikely(nfserr != NFS4_OK))
 567                 goto out_default;
 568 out:
 569         return status;
 570 out_default:
 571         return nfs_cb_stat_to_errno(status);
 572 }
 573
 574 /*
 575  * RPC procedure tables
 576  */
 577 #define PROC(proc, call, argtype, restype)                              \
 578 [NFSPROC4_CLNT_##proc] = {                                              \
 579         .p_proc    = NFSPROC4_CB_##call,                                \
 580         .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
 581         .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
 582         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 583         .p_replen  = NFS4_dec_##restype##_sz,                           \
 584         .p_statidx = NFSPROC4_CB_##call,                                \
 585         .p_name    = #proc,                                             \
 586 }
 587
 588 static struct rpc_procinfo nfs4_cb_procedures[] = {
 589         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 590         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 591 };
 592
 593 static struct rpc_version nfs_cb_version4 = {
 594 /*
 595  * Note on the callback rpc program version number: despite language in rfc
 596  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 597  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 598  * in practice that appears to be what implementations use.  The section
 599  * 18.36.3 language is expected to be fixed in an erratum.
 600  */
 601         .number                 = 1,
 602         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 603         .procs                  = nfs4_cb_procedures
 604 };
 605
 606 static struct rpc_version *nfs_cb_version[] = {
 607         &nfs_cb_version4,
 608 };
 609
 610 static struct rpc_program cb_program;
 611
 612 static struct rpc_stat cb_stats = {
 613         .program                = &cb_program
 614 };
 615
 616 #define NFS4_CALLBACK 0x40000000
 617 static struct rpc_program cb_program = {
 618         .name                   = "nfs4_cb",
 619         .number                 = NFS4_CALLBACK,
 620         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 621         .version                = nfs_cb_version,
 622         .stats                  = &cb_stats,
 623         .pipe_dir_name          = "/nfsd4_cb",
 624 };
 625
 626 static int max_cb_time(void)
 627 {
 628         return max(nfsd4_lease/10, (time_t)1) * HZ;
 629 }
 630
 631
 632 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 633 {
 634         struct rpc_timeout      timeparms = {
 635                 .to_initval     = max_cb_time(),
 636                 .to_retries     = 0,
 637         };
 638         struct rpc_create_args args = {
 639                 .net            = &init_net,
 640                 .address        = (struct sockaddr *) &conn->cb_addr,
 641                 .addrsize       = conn->cb_addrlen,
 642                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 643                 .timeout        = &timeparms,
 644                 .program        = &cb_program,
 645                 .version        = 0,
 646                 .authflavor     = clp->cl_flavor,
 647                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 648         };
 649         struct rpc_clnt *client;
 650
 651         if (clp->cl_minorversion == 0) {
 652                 if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
 653                         return -EINVAL;
 654                 args.client_name = clp->cl_principal;
 655                 args.prognumber = conn->cb_prog,
 656                 args.protocol = XPRT_TRANSPORT_TCP;
 657                 clp->cl_cb_ident = conn->cb_ident;
 658         } else {
 659                 if (!conn->cb_xprt)
 660                         return -EINVAL;
 661                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 662                 clp->cl_cb_session = ses;
 663                 args.bc_xprt = conn->cb_xprt;
 664                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 665                 args.protocol = XPRT_TRANSPORT_BC_TCP;
 666         }
 667         /* Create RPC client */
 668         client = rpc_create(&args);
 669         if (IS_ERR(client)) {
 670                 dprintk("NFSD: couldn't create callback client: %ld\n",
 671                         PTR_ERR(client));
 672                 return PTR_ERR(client);
 673         }
 674         clp->cl_cb_client = client;
 675         return 0;
 676
 677 }
 678
 679 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 680 {
 681         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 682                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 683 }
 684
 685 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 686 {
 687         clp->cl_cb_state = NFSD4_CB_DOWN;
 688         warn_no_callback_path(clp, reason);
 689 }
 690
 691 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 692 {
 693         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 694
 695         if (task->tk_status)
 696                 nfsd4_mark_cb_down(clp, task->tk_status);
 697         else
 698                 clp->cl_cb_state = NFSD4_CB_UP;
 699 }
 700
 701 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 702         /* XXX: release method to ensure we set the cb channel down if
 703          * necessary on early failure? */
 704         .rpc_call_done = nfsd4_cb_probe_done,
 705 };
 706
 707 static struct rpc_cred *callback_cred;
 708
 709 int set_callback_cred(void)
 710 {
 711         if (callback_cred)
 712                 return 0;
 713         callback_cred = rpc_lookup_machine_cred();
 714         if (!callback_cred)
 715                 return -ENOMEM;
 716         return 0;
 717 }
 718
 719 static struct workqueue_struct *callback_wq;
 720
 721 static void run_nfsd4_cb(struct nfsd4_callback *cb)
 722 {
 723         queue_work(callback_wq, &cb->cb_work);
 724 }
 725
 726 static void do_probe_callback(struct nfs4_client *clp)
 727 {
 728         struct nfsd4_callback *cb = &clp->cl_cb_null;
 729
 730         cb->cb_op = NULL;
 731         cb->cb_clp = clp;
 732
 733         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
 734         cb->cb_msg.rpc_argp = NULL;
 735         cb->cb_msg.rpc_resp = NULL;
 736         cb->cb_msg.rpc_cred = callback_cred;
 737
 738         cb->cb_ops = &nfsd4_cb_probe_ops;
 739
 740         run_nfsd4_cb(cb);
 741 }
 742
 743 /*
 744  * Poke the callback thread to process any updates to the callback
 745  * parameters, and send a null probe.
 746  */
 747 void nfsd4_probe_callback(struct nfs4_client *clp)
 748 {
 749         /* XXX: atomicity?  Also, should we be using cl_cb_flags? */
 750         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 751         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
 752         do_probe_callback(clp);
 753 }
 754
 755 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 756 {
 757         nfsd4_probe_callback(clp);
 758         flush_workqueue(callback_wq);
 759 }
 760
 761 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 762 {
 763         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 764         spin_lock(&clp->cl_lock);
 765         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 766         spin_unlock(&clp->cl_lock);
 767 }
 768
 769 /*
 770  * There's currently a single callback channel slot.
 771  * If the slot is available, then mark it busy.  Otherwise, set the
 772  * thread for sleeping on the callback RPC wait queue.
 773  */
 774 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 775 {
 776         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 777                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 778                 dprintk("%s slot is busy\n", __func__);
 779                 return false;
 780         }
 781         return true;
 782 }
 783
 784 /*
 785  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 786  * slots, and mark callback channel down on communication errors.
 787  */
 788 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 789 {
 790         struct nfsd4_callback *cb = calldata;
 791         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 792         struct nfs4_client *clp = dp->dl_client;
 793         u32 minorversion = clp->cl_minorversion;
 794
 795         cb->cb_minorversion = minorversion;
 796         if (minorversion) {
 797                 if (!nfsd41_cb_get_slot(clp, task))
 798                         return;
 799         }
 800         spin_lock(&clp->cl_lock);
 801         if (list_empty(&cb->cb_per_client)) {
 802                 /* This is the first call, not a restart */
 803                 cb->cb_done = false;
 804                 list_add(&cb->cb_per_client, &clp->cl_callbacks);
 805         }
 806         spin_unlock(&clp->cl_lock);
 807         rpc_call_start(task);
 808 }
 809
 810 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 811 {
 812         struct nfsd4_callback *cb = calldata;
 813         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 814         struct nfs4_client *clp = dp->dl_client;
 815
 816         dprintk("%s: minorversion=%d\n", __func__,
 817                 clp->cl_minorversion);
 818
 819         if (clp->cl_minorversion) {
 820                 /* No need for lock, access serialized in nfsd4_cb_prepare */
 821                 ++clp->cl_cb_session->se_cb_seq_nr;
 822                 clear_bit(0, &clp->cl_cb_slot_busy);
 823                 rpc_wake_up_next(&clp->cl_cb_waitq);
 824                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
 825                         clp->cl_cb_session->se_cb_seq_nr);
 826
 827                 /* We're done looking into the sequence information */
 828                 task->tk_msg.rpc_resp = NULL;
 829         }
 830 }
 831
 832
 833 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 834 {
 835         struct nfsd4_callback *cb = calldata;
 836         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 837         struct nfs4_client *clp = dp->dl_client;
 838         struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
 839
 840         nfsd4_cb_done(task, calldata);
 841
 842         if (current_rpc_client != task->tk_client) {
 843                 /* We're shutting down or changing cl_cb_client; leave
 844                  * it to nfsd4_process_cb_update to restart the call if
 845                  * necessary. */
 846                 return;
 847         }
 848
 849         if (cb->cb_done)
 850                 return;
 851         switch (task->tk_status) {
 852         case 0:
 853                 cb->cb_done = true;
 854                 return;
 855         case -EBADHANDLE:
 856         case -NFS4ERR_BAD_STATEID:
 857                 /* Race: client probably got cb_recall
 858                  * before open reply granting delegation */
 859                 break;
 860         default:
 861                 /* Network partition? */
 862                 nfsd4_mark_cb_down(clp, task->tk_status);
 863         }
 864         if (dp->dl_retries--) {
 865                 rpc_delay(task, 2*HZ);
 866                 task->tk_status = 0;
 867                 rpc_restart_call_prepare(task);
 868                 return;
 869         }
 870         nfsd4_mark_cb_down(clp, task->tk_status);
 871         cb->cb_done = true;
 872 }
 873
 874 static void nfsd4_cb_recall_release(void *calldata)
 875 {
 876         struct nfsd4_callback *cb = calldata;
 877         struct nfs4_client *clp = cb->cb_clp;
 878         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 879
 880         if (cb->cb_done) {
 881                 spin_lock(&clp->cl_lock);
 882                 list_del(&cb->cb_per_client);
 883                 spin_unlock(&clp->cl_lock);
 884                 nfs4_put_delegation(dp);
 885         }
 886 }
 887
 888 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
 889         .rpc_call_prepare = nfsd4_cb_prepare,
 890         .rpc_call_done = nfsd4_cb_recall_done,
 891         .rpc_release = nfsd4_cb_recall_release,
 892 };
 893
 894 int nfsd4_create_callback_queue(void)
 895 {
 896         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
 897         if (!callback_wq)
 898                 return -ENOMEM;
 899         return 0;
 900 }
 901
 902 void nfsd4_destroy_callback_queue(void)
 903 {
 904         destroy_workqueue(callback_wq);
 905 }
 906
 907 /* must be called under the state lock */
 908 void nfsd4_shutdown_callback(struct nfs4_client *clp)
 909 {
 910         set_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags);
 911         /*
 912          * Note this won't actually result in a null callback;
 913          * instead, nfsd4_do_callback_rpc() will detect the killed
 914          * client, destroy the rpc client, and stop:
 915          */
 916         do_probe_callback(clp);
 917         flush_workqueue(callback_wq);
 918 }
 919
 920 static void nfsd4_release_cb(struct nfsd4_callback *cb)
 921 {
 922         if (cb->cb_ops->rpc_release)
 923                 cb->cb_ops->rpc_release(cb);
 924 }
 925
 926 /* requires cl_lock: */
 927 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
 928 {
 929         struct nfsd4_session *s;
 930         struct nfsd4_conn *c;
 931
 932         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
 933                 list_for_each_entry(c, &s->se_conns, cn_persession) {
 934                         if (c->cn_flags & NFS4_CDFC4_BACK)
 935                                 return c;
 936                 }
 937         }
 938         return NULL;
 939 }
 940
 941 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
 942 {
 943         struct nfs4_cb_conn conn;
 944         struct nfs4_client *clp = cb->cb_clp;
 945         struct nfsd4_session *ses = NULL;
 946         struct nfsd4_conn *c;
 947         int err;
 948
 949         /*
 950          * This is either an update, or the client dying; in either case,
 951          * kill the old client:
 952          */
 953         if (clp->cl_cb_client) {
 954                 rpc_shutdown_client(clp->cl_cb_client);
 955                 clp->cl_cb_client = NULL;
 956         }
 957         if (clp->cl_cb_conn.cb_xprt) {
 958                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
 959                 clp->cl_cb_conn.cb_xprt = NULL;
 960         }
 961         if (test_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags))
 962                 return;
 963         spin_lock(&clp->cl_lock);
 964         /*
 965          * Only serialized callback code is allowed to clear these
 966          * flags; main nfsd code can only set them:
 967          */
 968         BUG_ON(!clp->cl_cb_flags);
 969         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
 970         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
 971         c = __nfsd4_find_backchannel(clp);
 972         if (c) {
 973                 svc_xprt_get(c->cn_xprt);
 974                 conn.cb_xprt = c->cn_xprt;
 975                 ses = c->cn_session;
 976         }
 977         spin_unlock(&clp->cl_lock);
 978
 979         err = setup_callback_client(clp, &conn, ses);
 980         if (err) {
 981                 warn_no_callback_path(clp, err);
 982                 return;
 983         }
 984         /* Yay, the callback channel's back! Restart any callbacks: */
 985         list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
 986                 run_nfsd4_cb(cb);
 987 }
 988
 989 void nfsd4_do_callback_rpc(struct work_struct *w)
 990 {
 991         struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
 992         struct nfs4_client *clp = cb->cb_clp;
 993         struct rpc_clnt *clnt;
 994
 995         if (clp->cl_cb_flags)
 996                 nfsd4_process_cb_update(cb);
 997
 998         clnt = clp->cl_cb_client;
 999         if (!clnt) {
1000                 /* Callback channel broken, or client killed; give up: */
1001                 nfsd4_release_cb(cb);
1002                 return;
1003         }
1004         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1005                         cb->cb_ops, cb);
1006 }
1007
1008 void nfsd4_cb_recall(struct nfs4_delegation *dp)
1009 {
1010         struct nfsd4_callback *cb = &dp->dl_recall;
1011         struct nfs4_client *clp = dp->dl_client;
1012
1013         dp->dl_retries = 1;
1014         cb->cb_op = dp;
1015         cb->cb_clp = clp;
1016         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1017         cb->cb_msg.rpc_argp = cb;
1018         cb->cb_msg.rpc_resp = cb;
1019         cb->cb_msg.rpc_cred = callback_cred;
1020
1021         cb->cb_ops = &nfsd4_cb_recall_ops;
1022         dp->dl_retries = 1;
1023
1024         INIT_LIST_HEAD(&cb->cb_per_client);
1025         cb->cb_done = true;
1026
1027         run_nfsd4_cb(&dp->dl_recall);
1028 }