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 + 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(nfserr);
 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                 status = nfs_cb_stat_to_errno(nfserr);
 568 out:
 569         return status;
 570 }
 571
 572 /*
 573  * RPC procedure tables
 574  */
 575 #define PROC(proc, call, argtype, restype)                              \
 576 [NFSPROC4_CLNT_##proc] = {                                              \
 577         .p_proc    = NFSPROC4_CB_##call,                                \
 578         .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
 579         .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
 580         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 581         .p_replen  = NFS4_dec_##restype##_sz,                           \
 582         .p_statidx = NFSPROC4_CB_##call,                                \
 583         .p_name    = #proc,                                             \
 584 }
 585
 586 static struct rpc_procinfo nfs4_cb_procedures[] = {
 587         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 588         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 589 };
 590
 591 static struct rpc_version nfs_cb_version4 = {
 592 /*
 593  * Note on the callback rpc program version number: despite language in rfc
 594  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 595  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 596  * in practice that appears to be what implementations use.  The section
 597  * 18.36.3 language is expected to be fixed in an erratum.
 598  */
 599         .number                 = 1,
 600         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 601         .procs                  = nfs4_cb_procedures
 602 };
 603
 604 static struct rpc_version *nfs_cb_version[] = {
 605         &nfs_cb_version4,
 606 };
 607
 608 static struct rpc_program cb_program;
 609
 610 static struct rpc_stat cb_stats = {
 611         .program                = &cb_program
 612 };
 613
 614 #define NFS4_CALLBACK 0x40000000
 615 static struct rpc_program cb_program = {
 616         .name                   = "nfs4_cb",
 617         .number                 = NFS4_CALLBACK,
 618         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 619         .version                = nfs_cb_version,
 620         .stats                  = &cb_stats,
 621         .pipe_dir_name          = "/nfsd4_cb",
 622 };
 623
 624 static int max_cb_time(void)
 625 {
 626         return max(nfsd4_lease/10, (time_t)1) * HZ;
 627 }
 628
 629
 630 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 631 {
 632         struct rpc_timeout      timeparms = {
 633                 .to_initval     = max_cb_time(),
 634                 .to_retries     = 0,
 635         };
 636         struct rpc_create_args args = {
 637                 .net            = &init_net,
 638                 .address        = (struct sockaddr *) &conn->cb_addr,
 639                 .addrsize       = conn->cb_addrlen,
 640                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 641                 .timeout        = &timeparms,
 642                 .program        = &cb_program,
 643                 .version        = 0,
 644                 .authflavor     = clp->cl_flavor,
 645                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 646         };
 647         struct rpc_clnt *client;
 648
 649         if (clp->cl_minorversion == 0) {
 650                 if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
 651                         return -EINVAL;
 652                 args.client_name = clp->cl_principal;
 653                 args.prognumber = conn->cb_prog,
 654                 args.protocol = XPRT_TRANSPORT_TCP;
 655                 clp->cl_cb_ident = conn->cb_ident;
 656         } else {
 657                 if (!conn->cb_xprt)
 658                         return -EINVAL;
 659                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 660                 clp->cl_cb_session = ses;
 661                 args.bc_xprt = conn->cb_xprt;
 662                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 663                 args.protocol = XPRT_TRANSPORT_BC_TCP;
 664         }
 665         /* Create RPC client */
 666         client = rpc_create(&args);
 667         if (IS_ERR(client)) {
 668                 dprintk("NFSD: couldn't create callback client: %ld\n",
 669                         PTR_ERR(client));
 670                 return PTR_ERR(client);
 671         }
 672         clp->cl_cb_client = client;
 673         return 0;
 674
 675 }
 676
 677 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 678 {
 679         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 680                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 681 }
 682
 683 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 684 {
 685         clp->cl_cb_state = NFSD4_CB_DOWN;
 686         warn_no_callback_path(clp, reason);
 687 }
 688
 689 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 690 {
 691         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 692
 693         if (task->tk_status)
 694                 nfsd4_mark_cb_down(clp, task->tk_status);
 695         else
 696                 clp->cl_cb_state = NFSD4_CB_UP;
 697 }
 698
 699 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 700         /* XXX: release method to ensure we set the cb channel down if
 701          * necessary on early failure? */
 702         .rpc_call_done = nfsd4_cb_probe_done,
 703 };
 704
 705 static struct rpc_cred *callback_cred;
 706
 707 int set_callback_cred(void)
 708 {
 709         if (callback_cred)
 710                 return 0;
 711         callback_cred = rpc_lookup_machine_cred();
 712         if (!callback_cred)
 713                 return -ENOMEM;
 714         return 0;
 715 }
 716
 717 static struct workqueue_struct *callback_wq;
 718
 719 static void run_nfsd4_cb(struct nfsd4_callback *cb)
 720 {
 721         queue_work(callback_wq, &cb->cb_work);
 722 }
 723
 724 static void do_probe_callback(struct nfs4_client *clp)
 725 {
 726         struct nfsd4_callback *cb = &clp->cl_cb_null;
 727
 728         cb->cb_op = NULL;
 729         cb->cb_clp = clp;
 730
 731         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
 732         cb->cb_msg.rpc_argp = NULL;
 733         cb->cb_msg.rpc_resp = NULL;
 734         cb->cb_msg.rpc_cred = callback_cred;
 735
 736         cb->cb_ops = &nfsd4_cb_probe_ops;
 737
 738         run_nfsd4_cb(cb);
 739 }
 740
 741 /*
 742  * Poke the callback thread to process any updates to the callback
 743  * parameters, and send a null probe.
 744  */
 745 void nfsd4_probe_callback(struct nfs4_client *clp)
 746 {
 747         /* XXX: atomicity?  Also, should we be using cl_cb_flags? */
 748         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 749         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
 750         do_probe_callback(clp);
 751 }
 752
 753 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 754 {
 755         nfsd4_probe_callback(clp);
 756         flush_workqueue(callback_wq);
 757 }
 758
 759 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 760 {
 761         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 762         spin_lock(&clp->cl_lock);
 763         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 764         spin_unlock(&clp->cl_lock);
 765 }
 766
 767 /*
 768  * There's currently a single callback channel slot.
 769  * If the slot is available, then mark it busy.  Otherwise, set the
 770  * thread for sleeping on the callback RPC wait queue.
 771  */
 772 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 773 {
 774         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 775                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 776                 dprintk("%s slot is busy\n", __func__);
 777                 return false;
 778         }
 779         return true;
 780 }
 781
 782 /*
 783  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 784  * slots, and mark callback channel down on communication errors.
 785  */
 786 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 787 {
 788         struct nfsd4_callback *cb = calldata;
 789         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 790         struct nfs4_client *clp = dp->dl_client;
 791         u32 minorversion = clp->cl_minorversion;
 792
 793         cb->cb_minorversion = minorversion;
 794         if (minorversion) {
 795                 if (!nfsd41_cb_get_slot(clp, task))
 796                         return;
 797         }
 798         spin_lock(&clp->cl_lock);
 799         if (list_empty(&cb->cb_per_client)) {
 800                 /* This is the first call, not a restart */
 801                 cb->cb_done = false;
 802                 list_add(&cb->cb_per_client, &clp->cl_callbacks);
 803         }
 804         spin_unlock(&clp->cl_lock);
 805         rpc_call_start(task);
 806 }
 807
 808 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 809 {
 810         struct nfsd4_callback *cb = calldata;
 811         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 812         struct nfs4_client *clp = dp->dl_client;
 813
 814         dprintk("%s: minorversion=%d\n", __func__,
 815                 clp->cl_minorversion);
 816
 817         if (clp->cl_minorversion) {
 818                 /* No need for lock, access serialized in nfsd4_cb_prepare */
 819                 ++clp->cl_cb_session->se_cb_seq_nr;
 820                 clear_bit(0, &clp->cl_cb_slot_busy);
 821                 rpc_wake_up_next(&clp->cl_cb_waitq);
 822                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
 823                         clp->cl_cb_session->se_cb_seq_nr);
 824
 825                 /* We're done looking into the sequence information */
 826                 task->tk_msg.rpc_resp = NULL;
 827         }
 828 }
 829
 830
 831 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 832 {
 833         struct nfsd4_callback *cb = calldata;
 834         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 835         struct nfs4_client *clp = dp->dl_client;
 836         struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
 837
 838         nfsd4_cb_done(task, calldata);
 839
 840         if (current_rpc_client != task->tk_client) {
 841                 /* We're shutting down or changing cl_cb_client; leave
 842                  * it to nfsd4_process_cb_update to restart the call if
 843                  * necessary. */
 844                 return;
 845         }
 846
 847         if (cb->cb_done)
 848                 return;
 849         switch (task->tk_status) {
 850         case 0:
 851                 cb->cb_done = true;
 852                 return;
 853         case -EBADHANDLE:
 854         case -NFS4ERR_BAD_STATEID:
 855                 /* Race: client probably got cb_recall
 856                  * before open reply granting delegation */
 857                 break;
 858         default:
 859                 /* Network partition? */
 860                 nfsd4_mark_cb_down(clp, task->tk_status);
 861         }
 862         if (dp->dl_retries--) {
 863                 rpc_delay(task, 2*HZ);
 864                 task->tk_status = 0;
 865                 rpc_restart_call_prepare(task);
 866                 return;
 867         }
 868         nfsd4_mark_cb_down(clp, task->tk_status);
 869         cb->cb_done = true;
 870 }
 871
 872 static void nfsd4_cb_recall_release(void *calldata)
 873 {
 874         struct nfsd4_callback *cb = calldata;
 875         struct nfs4_client *clp = cb->cb_clp;
 876         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 877
 878         if (cb->cb_done) {
 879                 spin_lock(&clp->cl_lock);
 880                 list_del(&cb->cb_per_client);
 881                 spin_unlock(&clp->cl_lock);
 882                 nfs4_put_delegation(dp);
 883         }
 884 }
 885
 886 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
 887         .rpc_call_prepare = nfsd4_cb_prepare,
 888         .rpc_call_done = nfsd4_cb_recall_done,
 889         .rpc_release = nfsd4_cb_recall_release,
 890 };
 891
 892 int nfsd4_create_callback_queue(void)
 893 {
 894         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
 895         if (!callback_wq)
 896                 return -ENOMEM;
 897         return 0;
 898 }
 899
 900 void nfsd4_destroy_callback_queue(void)
 901 {
 902         destroy_workqueue(callback_wq);
 903 }
 904
 905 /* must be called under the state lock */
 906 void nfsd4_shutdown_callback(struct nfs4_client *clp)
 907 {
 908         set_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags);
 909         /*
 910          * Note this won't actually result in a null callback;
 911          * instead, nfsd4_do_callback_rpc() will detect the killed
 912          * client, destroy the rpc client, and stop:
 913          */
 914         do_probe_callback(clp);
 915         flush_workqueue(callback_wq);
 916 }
 917
 918 static void nfsd4_release_cb(struct nfsd4_callback *cb)
 919 {
 920         if (cb->cb_ops->rpc_release)
 921                 cb->cb_ops->rpc_release(cb);
 922 }
 923
 924 /* requires cl_lock: */
 925 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
 926 {
 927         struct nfsd4_session *s;
 928         struct nfsd4_conn *c;
 929
 930         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
 931                 list_for_each_entry(c, &s->se_conns, cn_persession) {
 932                         if (c->cn_flags & NFS4_CDFC4_BACK)
 933                                 return c;
 934                 }
 935         }
 936         return NULL;
 937 }
 938
 939 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
 940 {
 941         struct nfs4_cb_conn conn;
 942         struct nfs4_client *clp = cb->cb_clp;
 943         struct nfsd4_session *ses = NULL;
 944         struct nfsd4_conn *c;
 945         int err;
 946
 947         /*
 948          * This is either an update, or the client dying; in either case,
 949          * kill the old client:
 950          */
 951         if (clp->cl_cb_client) {
 952                 rpc_shutdown_client(clp->cl_cb_client);
 953                 clp->cl_cb_client = NULL;
 954         }
 955         if (clp->cl_cb_conn.cb_xprt) {
 956                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
 957                 clp->cl_cb_conn.cb_xprt = NULL;
 958         }
 959         if (test_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags))
 960                 return;
 961         spin_lock(&clp->cl_lock);
 962         /*
 963          * Only serialized callback code is allowed to clear these
 964          * flags; main nfsd code can only set them:
 965          */
 966         BUG_ON(!clp->cl_cb_flags);
 967         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
 968         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
 969         c = __nfsd4_find_backchannel(clp);
 970         if (c) {
 971                 svc_xprt_get(c->cn_xprt);
 972                 conn.cb_xprt = c->cn_xprt;
 973                 ses = c->cn_session;
 974         }
 975         spin_unlock(&clp->cl_lock);
 976
 977         err = setup_callback_client(clp, &conn, ses);
 978         if (err) {
 979                 warn_no_callback_path(clp, err);
 980                 return;
 981         }
 982         /* Yay, the callback channel's back! Restart any callbacks: */
 983         list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
 984                 run_nfsd4_cb(cb);
 985 }
 986
 987 void nfsd4_do_callback_rpc(struct work_struct *w)
 988 {
 989         struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
 990         struct nfs4_client *clp = cb->cb_clp;
 991         struct rpc_clnt *clnt;
 992
 993         if (clp->cl_cb_flags)
 994                 nfsd4_process_cb_update(cb);
 995
 996         clnt = clp->cl_cb_client;
 997         if (!clnt) {
 998                 /* Callback channel broken, or client killed; give up: */
 999                 nfsd4_release_cb(cb);
1000                 return;
1001         }
1002         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1003                         cb->cb_ops, cb);
1004 }
1005
1006 void nfsd4_cb_recall(struct nfs4_delegation *dp)
1007 {
1008         struct nfsd4_callback *cb = &dp->dl_recall;
1009         struct nfs4_client *clp = dp->dl_client;
1010
1011         dp->dl_retries = 1;
1012         cb->cb_op = dp;
1013         cb->cb_clp = clp;
1014         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1015         cb->cb_msg.rpc_argp = cb;
1016         cb->cb_msg.rpc_resp = cb;
1017         cb->cb_msg.rpc_cred = callback_cred;
1018
1019         cb->cb_ops = &nfsd4_cb_recall_ops;
1020         dp->dl_retries = 1;
1021
1022         INIT_LIST_HEAD(&cb->cb_per_client);
1023         cb->cb_done = true;
1024
1025         run_nfsd4_cb(&dp->dl_recall);
1026 }