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 #include "netns.h"
  40
  41 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  42
  43 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
  44
  45 #define NFSPROC4_CB_NULL 0
  46 #define NFSPROC4_CB_COMPOUND 1
  47
  48 /* Index of predefined Linux callback client operations */
  49
  50 enum {
  51         NFSPROC4_CLNT_CB_NULL = 0,
  52         NFSPROC4_CLNT_CB_RECALL,
  53         NFSPROC4_CLNT_CB_SEQUENCE,
  54 };
  55
  56 #define NFS4_MAXTAGLEN          20
  57
  58 #define NFS4_enc_cb_null_sz             0
  59 #define NFS4_dec_cb_null_sz             0
  60 #define cb_compound_enc_hdr_sz          4
  61 #define cb_compound_dec_hdr_sz          (3 + (NFS4_MAXTAGLEN >> 2))
  62 #define sessionid_sz                    (NFS4_MAX_SESSIONID_LEN >> 2)
  63 #define cb_sequence_enc_sz              (sessionid_sz + 4 +             \
  64                                         1 /* no referring calls list yet */)
  65 #define cb_sequence_dec_sz              (op_dec_sz + sessionid_sz + 4)
  66
  67 #define op_enc_sz                       1
  68 #define op_dec_sz                       2
  69 #define enc_nfs4_fh_sz                  (1 + (NFS4_FHSIZE >> 2))
  70 #define enc_stateid_sz                  (NFS4_STATEID_SIZE >> 2)
  71 #define NFS4_enc_cb_recall_sz           (cb_compound_enc_hdr_sz +       \
  72                                         cb_sequence_enc_sz +            \
  73                                         1 + enc_stateid_sz +            \
  74                                         enc_nfs4_fh_sz)
  75
  76 #define NFS4_dec_cb_recall_sz           (cb_compound_dec_hdr_sz  +      \
  77                                         cb_sequence_dec_sz +            \
  78                                         op_dec_sz)
  79
  80 struct nfs4_cb_compound_hdr {
  81         /* args */
  82         u32             ident;  /* minorversion 0 only */
  83         u32             nops;
  84         __be32          *nops_p;
  85         u32             minorversion;
  86         /* res */
  87         int             status;
  88 };
  89
  90 /*
  91  * Handle decode buffer overflows out-of-line.
  92  */
  93 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  94 {
  95         dprintk("NFS: %s prematurely hit the end of our receive buffer. "
  96                 "Remaining buffer length is %tu words.\n",
  97                 func, xdr->end - xdr->p);
  98 }
  99
 100 static __be32 *xdr_encode_empty_array(__be32 *p)
 101 {
 102         *p++ = xdr_zero;
 103         return p;
 104 }
 105
 106 /*
 107  * Encode/decode NFSv4 CB basic data types
 108  *
 109  * Basic NFSv4 callback data types are defined in section 15 of RFC
 110  * 3530: "Network File System (NFS) version 4 Protocol" and section
 111  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
 112  * 1 Protocol"
 113  */
 114
 115 /*
 116  *      nfs_cb_opnum4
 117  *
 118  *      enum nfs_cb_opnum4 {
 119  *              OP_CB_GETATTR           = 3,
 120  *                ...
 121  *      };
 122  */
 123 enum nfs_cb_opnum4 {
 124         OP_CB_GETATTR                   = 3,
 125         OP_CB_RECALL                    = 4,
 126         OP_CB_LAYOUTRECALL              = 5,
 127         OP_CB_NOTIFY                    = 6,
 128         OP_CB_PUSH_DELEG                = 7,
 129         OP_CB_RECALL_ANY                = 8,
 130         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
 131         OP_CB_RECALL_SLOT               = 10,
 132         OP_CB_SEQUENCE                  = 11,
 133         OP_CB_WANTS_CANCELLED           = 12,
 134         OP_CB_NOTIFY_LOCK               = 13,
 135         OP_CB_NOTIFY_DEVICEID           = 14,
 136         OP_CB_ILLEGAL                   = 10044
 137 };
 138
 139 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 140 {
 141         __be32 *p;
 142
 143         p = xdr_reserve_space(xdr, 4);
 144         *p = cpu_to_be32(op);
 145 }
 146
 147 /*
 148  * nfs_fh4
 149  *
 150  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 151  */
 152 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 153 {
 154         u32 length = fh->fh_size;
 155         __be32 *p;
 156
 157         BUG_ON(length > NFS4_FHSIZE);
 158         p = xdr_reserve_space(xdr, 4 + length);
 159         xdr_encode_opaque(p, &fh->fh_base, length);
 160 }
 161
 162 /*
 163  * stateid4
 164  *
 165  *      struct stateid4 {
 166  *              uint32_t        seqid;
 167  *              opaque          other[12];
 168  *      };
 169  */
 170 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 171 {
 172         __be32 *p;
 173
 174         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 175         *p++ = cpu_to_be32(sid->si_generation);
 176         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 177 }
 178
 179 /*
 180  * sessionid4
 181  *
 182  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 183  */
 184 static void encode_sessionid4(struct xdr_stream *xdr,
 185                               const struct nfsd4_session *session)
 186 {
 187         __be32 *p;
 188
 189         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 190         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 191                                         NFS4_MAX_SESSIONID_LEN);
 192 }
 193
 194 /*
 195  * nfsstat4
 196  */
 197 static const struct {
 198         int stat;
 199         int errno;
 200 } nfs_cb_errtbl[] = {
 201         { NFS4_OK,              0               },
 202         { NFS4ERR_PERM,         -EPERM          },
 203         { NFS4ERR_NOENT,        -ENOENT         },
 204         { NFS4ERR_IO,           -EIO            },
 205         { NFS4ERR_NXIO,         -ENXIO          },
 206         { NFS4ERR_ACCESS,       -EACCES         },
 207         { NFS4ERR_EXIST,        -EEXIST         },
 208         { NFS4ERR_XDEV,         -EXDEV          },
 209         { NFS4ERR_NOTDIR,       -ENOTDIR        },
 210         { NFS4ERR_ISDIR,        -EISDIR         },
 211         { NFS4ERR_INVAL,        -EINVAL         },
 212         { NFS4ERR_FBIG,         -EFBIG          },
 213         { NFS4ERR_NOSPC,        -ENOSPC         },
 214         { NFS4ERR_ROFS,         -EROFS          },
 215         { NFS4ERR_MLINK,        -EMLINK         },
 216         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 217         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 218         { NFS4ERR_DQUOT,        -EDQUOT         },
 219         { NFS4ERR_STALE,        -ESTALE         },
 220         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 221         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 222         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 223         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 224         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 225         { NFS4ERR_BADTYPE,      -EBADTYPE       },
 226         { NFS4ERR_LOCKED,       -EAGAIN         },
 227         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 228         { NFS4ERR_SYMLINK,      -ELOOP          },
 229         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 230         { NFS4ERR_DEADLOCK,     -EDEADLK        },
 231         { -1,                   -EIO            }
 232 };
 233
 234 /*
 235  * If we cannot translate the error, the recovery routines should
 236  * handle it.
 237  *
 238  * Note: remaining NFSv4 error codes have values > 10000, so should
 239  * not conflict with native Linux error codes.
 240  */
 241 static int nfs_cb_stat_to_errno(int status)
 242 {
 243         int i;
 244
 245         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 246                 if (nfs_cb_errtbl[i].stat == status)
 247                         return nfs_cb_errtbl[i].errno;
 248         }
 249
 250         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 251         return -status;
 252 }
 253
 254 static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
 255                                enum nfsstat4 *status)
 256 {
 257         __be32 *p;
 258         u32 op;
 259
 260         p = xdr_inline_decode(xdr, 4 + 4);
 261         if (unlikely(p == NULL))
 262                 goto out_overflow;
 263         op = be32_to_cpup(p++);
 264         if (unlikely(op != expected))
 265                 goto out_unexpected;
 266         *status = be32_to_cpup(p);
 267         return 0;
 268 out_overflow:
 269         print_overflow_msg(__func__, xdr);
 270         return -EIO;
 271 out_unexpected:
 272         dprintk("NFSD: Callback server returned operation %d but "
 273                 "we issued a request for %d\n", op, expected);
 274         return -EIO;
 275 }
 276
 277 /*
 278  * CB_COMPOUND4args
 279  *
 280  *      struct CB_COMPOUND4args {
 281  *              utf8str_cs      tag;
 282  *              uint32_t        minorversion;
 283  *              uint32_t        callback_ident;
 284  *              nfs_cb_argop4   argarray<>;
 285  *      };
 286 */
 287 static void encode_cb_compound4args(struct xdr_stream *xdr,
 288                                     struct nfs4_cb_compound_hdr *hdr)
 289 {
 290         __be32 * p;
 291
 292         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 293         p = xdr_encode_empty_array(p);          /* empty tag */
 294         *p++ = cpu_to_be32(hdr->minorversion);
 295         *p++ = cpu_to_be32(hdr->ident);
 296
 297         hdr->nops_p = p;
 298         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 299 }
 300
 301 /*
 302  * Update argarray element count
 303  */
 304 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 305 {
 306         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 307         *hdr->nops_p = cpu_to_be32(hdr->nops);
 308 }
 309
 310 /*
 311  * CB_COMPOUND4res
 312  *
 313  *      struct CB_COMPOUND4res {
 314  *              nfsstat4        status;
 315  *              utf8str_cs      tag;
 316  *              nfs_cb_resop4   resarray<>;
 317  *      };
 318  */
 319 static int decode_cb_compound4res(struct xdr_stream *xdr,
 320                                   struct nfs4_cb_compound_hdr *hdr)
 321 {
 322         u32 length;
 323         __be32 *p;
 324
 325         p = xdr_inline_decode(xdr, 4 + 4);
 326         if (unlikely(p == NULL))
 327                 goto out_overflow;
 328         hdr->status = be32_to_cpup(p++);
 329         /* Ignore the tag */
 330         length = be32_to_cpup(p++);
 331         p = xdr_inline_decode(xdr, length + 4);
 332         if (unlikely(p == NULL))
 333                 goto out_overflow;
 334         hdr->nops = be32_to_cpup(p);
 335         return 0;
 336 out_overflow:
 337         print_overflow_msg(__func__, xdr);
 338         return -EIO;
 339 }
 340
 341 /*
 342  * CB_RECALL4args
 343  *
 344  *      struct CB_RECALL4args {
 345  *              stateid4        stateid;
 346  *              bool            truncate;
 347  *              nfs_fh4         fh;
 348  *      };
 349  */
 350 static void encode_cb_recall4args(struct xdr_stream *xdr,
 351                                   const struct nfs4_delegation *dp,
 352                                   struct nfs4_cb_compound_hdr *hdr)
 353 {
 354         __be32 *p;
 355
 356         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 357         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 358
 359         p = xdr_reserve_space(xdr, 4);
 360         *p++ = xdr_zero;                        /* truncate */
 361
 362         encode_nfs_fh4(xdr, &dp->dl_fh);
 363
 364         hdr->nops++;
 365 }
 366
 367 /*
 368  * CB_SEQUENCE4args
 369  *
 370  *      struct CB_SEQUENCE4args {
 371  *              sessionid4              csa_sessionid;
 372  *              sequenceid4             csa_sequenceid;
 373  *              slotid4                 csa_slotid;
 374  *              slotid4                 csa_highest_slotid;
 375  *              bool                    csa_cachethis;
 376  *              referring_call_list4    csa_referring_call_lists<>;
 377  *      };
 378  */
 379 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 380                                     const struct nfsd4_callback *cb,
 381                                     struct nfs4_cb_compound_hdr *hdr)
 382 {
 383         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 384         __be32 *p;
 385
 386         if (hdr->minorversion == 0)
 387                 return;
 388
 389         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 390         encode_sessionid4(xdr, session);
 391
 392         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 393         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 394         *p++ = xdr_zero;                        /* csa_slotid */
 395         *p++ = xdr_zero;                        /* csa_highest_slotid */
 396         *p++ = xdr_zero;                        /* csa_cachethis */
 397         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 398
 399         hdr->nops++;
 400 }
 401
 402 /*
 403  * CB_SEQUENCE4resok
 404  *
 405  *      struct CB_SEQUENCE4resok {
 406  *              sessionid4      csr_sessionid;
 407  *              sequenceid4     csr_sequenceid;
 408  *              slotid4         csr_slotid;
 409  *              slotid4         csr_highest_slotid;
 410  *              slotid4         csr_target_highest_slotid;
 411  *      };
 412  *
 413  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 414  *      case NFS4_OK:
 415  *              CB_SEQUENCE4resok       csr_resok4;
 416  *      default:
 417  *              void;
 418  *      };
 419  *
 420  * Our current back channel implmentation supports a single backchannel
 421  * with a single slot.
 422  */
 423 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 424                                     struct nfsd4_callback *cb)
 425 {
 426         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 427         struct nfs4_sessionid id;
 428         int status;
 429         __be32 *p;
 430         u32 dummy;
 431
 432         status = -ESERVERFAULT;
 433
 434         /*
 435          * If the server returns different values for sessionID, slotID or
 436          * sequence number, the server is looney tunes.
 437          */
 438         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 439         if (unlikely(p == NULL))
 440                 goto out_overflow;
 441         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
 442         if (memcmp(id.data, session->se_sessionid.data,
 443                                         NFS4_MAX_SESSIONID_LEN) != 0) {
 444                 dprintk("NFS: %s Invalid session id\n", __func__);
 445                 goto out;
 446         }
 447         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 448
 449         dummy = be32_to_cpup(p++);
 450         if (dummy != session->se_cb_seq_nr) {
 451                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 452                 goto out;
 453         }
 454
 455         dummy = be32_to_cpup(p++);
 456         if (dummy != 0) {
 457                 dprintk("NFS: %s Invalid slotid\n", __func__);
 458                 goto out;
 459         }
 460
 461         /*
 462          * FIXME: process highest slotid and target highest slotid
 463          */
 464         status = 0;
 465 out:
 466         if (status)
 467                 nfsd4_mark_cb_fault(cb->cb_clp, status);
 468         return status;
 469 out_overflow:
 470         print_overflow_msg(__func__, xdr);
 471         return -EIO;
 472 }
 473
 474 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 475                                   struct nfsd4_callback *cb)
 476 {
 477         enum nfsstat4 nfserr;
 478         int status;
 479
 480         if (cb->cb_minorversion == 0)
 481                 return 0;
 482
 483         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
 484         if (unlikely(status))
 485                 goto out;
 486         if (unlikely(nfserr != NFS4_OK))
 487                 goto out_default;
 488         status = decode_cb_sequence4resok(xdr, cb);
 489 out:
 490         return status;
 491 out_default:
 492         return nfs_cb_stat_to_errno(nfserr);
 493 }
 494
 495 /*
 496  * NFSv4.0 and NFSv4.1 XDR encode functions
 497  *
 498  * NFSv4.0 callback argument types are defined in section 15 of RFC
 499  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 500  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 501  * Protocol".
 502  */
 503
 504 /*
 505  * NB: Without this zero space reservation, callbacks over krb5p fail
 506  */
 507 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 508                                  void *__unused)
 509 {
 510         xdr_reserve_space(xdr, 0);
 511 }
 512
 513 /*
 514  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 515  */
 516 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 517                                    const struct nfsd4_callback *cb)
 518 {
 519         const struct nfs4_delegation *args = cb->cb_op;
 520         struct nfs4_cb_compound_hdr hdr = {
 521                 .ident = cb->cb_clp->cl_cb_ident,
 522                 .minorversion = cb->cb_minorversion,
 523         };
 524
 525         encode_cb_compound4args(xdr, &hdr);
 526         encode_cb_sequence4args(xdr, cb, &hdr);
 527         encode_cb_recall4args(xdr, args, &hdr);
 528         encode_cb_nops(&hdr);
 529 }
 530
 531
 532 /*
 533  * NFSv4.0 and NFSv4.1 XDR decode functions
 534  *
 535  * NFSv4.0 callback result types are defined in section 15 of RFC
 536  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 537  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 538  * Protocol".
 539  */
 540
 541 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 542                                 void *__unused)
 543 {
 544         return 0;
 545 }
 546
 547 /*
 548  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 549  */
 550 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 551                                   struct xdr_stream *xdr,
 552                                   struct nfsd4_callback *cb)
 553 {
 554         struct nfs4_cb_compound_hdr hdr;
 555         enum nfsstat4 nfserr;
 556         int status;
 557
 558         status = decode_cb_compound4res(xdr, &hdr);
 559         if (unlikely(status))
 560                 goto out;
 561
 562         if (cb != NULL) {
 563                 status = decode_cb_sequence4res(xdr, cb);
 564                 if (unlikely(status))
 565                         goto out;
 566         }
 567
 568         status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
 569         if (unlikely(status))
 570                 goto out;
 571         if (unlikely(nfserr != NFS4_OK))
 572                 status = nfs_cb_stat_to_errno(nfserr);
 573 out:
 574         return status;
 575 }
 576
 577 /*
 578  * RPC procedure tables
 579  */
 580 #define PROC(proc, call, argtype, restype)                              \
 581 [NFSPROC4_CLNT_##proc] = {                                              \
 582         .p_proc    = NFSPROC4_CB_##call,                                \
 583         .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
 584         .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
 585         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 586         .p_replen  = NFS4_dec_##restype##_sz,                           \
 587         .p_statidx = NFSPROC4_CB_##call,                                \
 588         .p_name    = #proc,                                             \
 589 }
 590
 591 static struct rpc_procinfo nfs4_cb_procedures[] = {
 592         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 593         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 594 };
 595
 596 static struct rpc_version nfs_cb_version4 = {
 597 /*
 598  * Note on the callback rpc program version number: despite language in rfc
 599  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 600  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 601  * in practice that appears to be what implementations use.  The section
 602  * 18.36.3 language is expected to be fixed in an erratum.
 603  */
 604         .number                 = 1,
 605         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 606         .procs                  = nfs4_cb_procedures
 607 };
 608
 609 static const struct rpc_version *nfs_cb_version[] = {
 610         &nfs_cb_version4,
 611 };
 612
 613 static const struct rpc_program cb_program;
 614
 615 static struct rpc_stat cb_stats = {
 616         .program                = &cb_program
 617 };
 618
 619 #define NFS4_CALLBACK 0x40000000
 620 static const struct rpc_program cb_program = {
 621         .name                   = "nfs4_cb",
 622         .number                 = NFS4_CALLBACK,
 623         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 624         .version                = nfs_cb_version,
 625         .stats                  = &cb_stats,
 626         .pipe_dir_name          = "nfsd4_cb",
 627 };
 628
 629 static int max_cb_time(struct net *net)
 630 {
 631         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 632         return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
 633 }
 634
 635 static struct rpc_cred *callback_cred;
 636
 637 int set_callback_cred(void)
 638 {
 639         if (callback_cred)
 640                 return 0;
 641         callback_cred = rpc_lookup_machine_cred("nfs");
 642         if (!callback_cred)
 643                 return -ENOMEM;
 644         return 0;
 645 }
 646
 647 static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 648 {
 649         if (clp->cl_minorversion == 0) {
 650                 return get_rpccred(callback_cred);
 651         } else {
 652                 struct rpc_auth *auth = client->cl_auth;
 653                 struct auth_cred acred = {};
 654
 655                 acred.uid = ses->se_cb_sec.uid;
 656                 acred.gid = ses->se_cb_sec.gid;
 657                 return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
 658         }
 659 }
 660
 661 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 662 {
 663         struct rpc_timeout      timeparms = {
 664                 .to_initval     = max_cb_time(clp->net),
 665                 .to_retries     = 0,
 666         };
 667         struct rpc_create_args args = {
 668                 .net            = clp->net,
 669                 .address        = (struct sockaddr *) &conn->cb_addr,
 670                 .addrsize       = conn->cb_addrlen,
 671                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 672                 .timeout        = &timeparms,
 673                 .program        = &cb_program,
 674                 .version        = 0,
 675                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 676         };
 677         struct rpc_clnt *client;
 678         struct rpc_cred *cred;
 679
 680         if (clp->cl_minorversion == 0) {
 681                 if (!clp->cl_cred.cr_principal &&
 682                                 (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
 683                         return -EINVAL;
 684                 args.client_name = clp->cl_cred.cr_principal;
 685                 args.prognumber = conn->cb_prog,
 686                 args.protocol = XPRT_TRANSPORT_TCP;
 687                 args.authflavor = clp->cl_cred.cr_flavor;
 688                 clp->cl_cb_ident = conn->cb_ident;
 689         } else {
 690                 if (!conn->cb_xprt)
 691                         return -EINVAL;
 692                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 693                 clp->cl_cb_session = ses;
 694                 args.bc_xprt = conn->cb_xprt;
 695                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 696                 args.protocol = XPRT_TRANSPORT_BC_TCP;
 697                 args.authflavor = ses->se_cb_sec.flavor;
 698         }
 699         /* Create RPC client */
 700         client = rpc_create(&args);
 701         if (IS_ERR(client)) {
 702                 dprintk("NFSD: couldn't create callback client: %ld\n",
 703                         PTR_ERR(client));
 704                 return PTR_ERR(client);
 705         }
 706         cred = get_backchannel_cred(clp, client, ses);
 707         if (IS_ERR(cred)) {
 708                 rpc_shutdown_client(client);
 709                 return PTR_ERR(cred);
 710         }
 711         clp->cl_cb_client = client;
 712         clp->cl_cb_cred = cred;
 713         return 0;
 714 }
 715
 716 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 717 {
 718         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 719                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 720 }
 721
 722 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 723 {
 724         clp->cl_cb_state = NFSD4_CB_DOWN;
 725         warn_no_callback_path(clp, reason);
 726 }
 727
 728 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 729 {
 730         clp->cl_cb_state = NFSD4_CB_FAULT;
 731         warn_no_callback_path(clp, reason);
 732 }
 733
 734 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 735 {
 736         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 737
 738         if (task->tk_status)
 739                 nfsd4_mark_cb_down(clp, task->tk_status);
 740         else
 741                 clp->cl_cb_state = NFSD4_CB_UP;
 742 }
 743
 744 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 745         /* XXX: release method to ensure we set the cb channel down if
 746          * necessary on early failure? */
 747         .rpc_call_done = nfsd4_cb_probe_done,
 748 };
 749
 750 static struct workqueue_struct *callback_wq;
 751
 752 static void run_nfsd4_cb(struct nfsd4_callback *cb)
 753 {
 754         queue_work(callback_wq, &cb->cb_work);
 755 }
 756
 757 static void do_probe_callback(struct nfs4_client *clp)
 758 {
 759         struct nfsd4_callback *cb = &clp->cl_cb_null;
 760
 761         cb->cb_op = NULL;
 762         cb->cb_clp = clp;
 763
 764         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
 765         cb->cb_msg.rpc_argp = NULL;
 766         cb->cb_msg.rpc_resp = NULL;
 767
 768         cb->cb_ops = &nfsd4_cb_probe_ops;
 769
 770         run_nfsd4_cb(cb);
 771 }
 772
 773 /*
 774  * Poke the callback thread to process any updates to the callback
 775  * parameters, and send a null probe.
 776  */
 777 void nfsd4_probe_callback(struct nfs4_client *clp)
 778 {
 779         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 780         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 781         do_probe_callback(clp);
 782 }
 783
 784 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 785 {
 786         nfsd4_probe_callback(clp);
 787         flush_workqueue(callback_wq);
 788 }
 789
 790 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 791 {
 792         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 793         spin_lock(&clp->cl_lock);
 794         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 795         spin_unlock(&clp->cl_lock);
 796 }
 797
 798 /*
 799  * There's currently a single callback channel slot.
 800  * If the slot is available, then mark it busy.  Otherwise, set the
 801  * thread for sleeping on the callback RPC wait queue.
 802  */
 803 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 804 {
 805         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 806                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 807                 dprintk("%s slot is busy\n", __func__);
 808                 return false;
 809         }
 810         return true;
 811 }
 812
 813 /*
 814  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 815  * slots, and mark callback channel down on communication errors.
 816  */
 817 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 818 {
 819         struct nfsd4_callback *cb = calldata;
 820         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 821         struct nfs4_client *clp = dp->dl_stid.sc_client;
 822         u32 minorversion = clp->cl_minorversion;
 823
 824         cb->cb_minorversion = minorversion;
 825         if (minorversion) {
 826                 if (!nfsd41_cb_get_slot(clp, task))
 827                         return;
 828         }
 829         spin_lock(&clp->cl_lock);
 830         if (list_empty(&cb->cb_per_client)) {
 831                 /* This is the first call, not a restart */
 832                 cb->cb_done = false;
 833                 list_add(&cb->cb_per_client, &clp->cl_callbacks);
 834         }
 835         spin_unlock(&clp->cl_lock);
 836         rpc_call_start(task);
 837 }
 838
 839 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 840 {
 841         struct nfsd4_callback *cb = calldata;
 842         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 843         struct nfs4_client *clp = dp->dl_stid.sc_client;
 844
 845         dprintk("%s: minorversion=%d\n", __func__,
 846                 clp->cl_minorversion);
 847
 848         if (clp->cl_minorversion) {
 849                 /* No need for lock, access serialized in nfsd4_cb_prepare */
 850                 ++clp->cl_cb_session->se_cb_seq_nr;
 851                 clear_bit(0, &clp->cl_cb_slot_busy);
 852                 rpc_wake_up_next(&clp->cl_cb_waitq);
 853                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
 854                         clp->cl_cb_session->se_cb_seq_nr);
 855
 856                 /* We're done looking into the sequence information */
 857                 task->tk_msg.rpc_resp = NULL;
 858         }
 859 }
 860
 861
 862 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 863 {
 864         struct nfsd4_callback *cb = calldata;
 865         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 866         struct nfs4_client *clp = dp->dl_stid.sc_client;
 867         struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
 868
 869         nfsd4_cb_done(task, calldata);
 870
 871         if (current_rpc_client != task->tk_client) {
 872                 /* We're shutting down or changing cl_cb_client; leave
 873                  * it to nfsd4_process_cb_update to restart the call if
 874                  * necessary. */
 875                 return;
 876         }
 877
 878         if (cb->cb_done)
 879                 return;
 880         switch (task->tk_status) {
 881         case 0:
 882                 cb->cb_done = true;
 883                 return;
 884         case -EBADHANDLE:
 885         case -NFS4ERR_BAD_STATEID:
 886                 /* Race: client probably got cb_recall
 887                  * before open reply granting delegation */
 888                 break;
 889         default:
 890                 /* Network partition? */
 891                 nfsd4_mark_cb_down(clp, task->tk_status);
 892         }
 893         if (dp->dl_retries--) {
 894                 rpc_delay(task, 2*HZ);
 895                 task->tk_status = 0;
 896                 rpc_restart_call_prepare(task);
 897                 return;
 898         }
 899         nfsd4_mark_cb_down(clp, task->tk_status);
 900         cb->cb_done = true;
 901 }
 902
 903 static void nfsd4_cb_recall_release(void *calldata)
 904 {
 905         struct nfsd4_callback *cb = calldata;
 906         struct nfs4_client *clp = cb->cb_clp;
 907         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 908
 909         if (cb->cb_done) {
 910                 spin_lock(&clp->cl_lock);
 911                 list_del(&cb->cb_per_client);
 912                 spin_unlock(&clp->cl_lock);
 913                 nfs4_put_delegation(dp);
 914         }
 915 }
 916
 917 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
 918         .rpc_call_prepare = nfsd4_cb_prepare,
 919         .rpc_call_done = nfsd4_cb_recall_done,
 920         .rpc_release = nfsd4_cb_recall_release,
 921 };
 922
 923 int nfsd4_create_callback_queue(void)
 924 {
 925         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
 926         if (!callback_wq)
 927                 return -ENOMEM;
 928         return 0;
 929 }
 930
 931 void nfsd4_destroy_callback_queue(void)
 932 {
 933         destroy_workqueue(callback_wq);
 934 }
 935
 936 /* must be called under the state lock */
 937 void nfsd4_shutdown_callback(struct nfs4_client *clp)
 938 {
 939         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
 940         /*
 941          * Note this won't actually result in a null callback;
 942          * instead, nfsd4_do_callback_rpc() will detect the killed
 943          * client, destroy the rpc client, and stop:
 944          */
 945         do_probe_callback(clp);
 946         flush_workqueue(callback_wq);
 947 }
 948
 949 static void nfsd4_release_cb(struct nfsd4_callback *cb)
 950 {
 951         if (cb->cb_ops->rpc_release)
 952                 cb->cb_ops->rpc_release(cb);
 953 }
 954
 955 /* requires cl_lock: */
 956 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
 957 {
 958         struct nfsd4_session *s;
 959         struct nfsd4_conn *c;
 960
 961         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
 962                 list_for_each_entry(c, &s->se_conns, cn_persession) {
 963                         if (c->cn_flags & NFS4_CDFC4_BACK)
 964                                 return c;
 965                 }
 966         }
 967         return NULL;
 968 }
 969
 970 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
 971 {
 972         struct nfs4_cb_conn conn;
 973         struct nfs4_client *clp = cb->cb_clp;
 974         struct nfsd4_session *ses = NULL;
 975         struct nfsd4_conn *c;
 976         int err;
 977
 978         /*
 979          * This is either an update, or the client dying; in either case,
 980          * kill the old client:
 981          */
 982         if (clp->cl_cb_client) {
 983                 rpc_shutdown_client(clp->cl_cb_client);
 984                 clp->cl_cb_client = NULL;
 985                 put_rpccred(clp->cl_cb_cred);
 986                 clp->cl_cb_cred = NULL;
 987         }
 988         if (clp->cl_cb_conn.cb_xprt) {
 989                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
 990                 clp->cl_cb_conn.cb_xprt = NULL;
 991         }
 992         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
 993                 return;
 994         spin_lock(&clp->cl_lock);
 995         /*
 996          * Only serialized callback code is allowed to clear these
 997          * flags; main nfsd code can only set them:
 998          */
 999         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1000         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1001         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1002         c = __nfsd4_find_backchannel(clp);
1003         if (c) {
1004                 svc_xprt_get(c->cn_xprt);
1005                 conn.cb_xprt = c->cn_xprt;
1006                 ses = c->cn_session;
1007         }
1008         spin_unlock(&clp->cl_lock);
1009
1010         err = setup_callback_client(clp, &conn, ses);
1011         if (err) {
1012                 nfsd4_mark_cb_down(clp, err);
1013                 return;
1014         }
1015         /* Yay, the callback channel's back! Restart any callbacks: */
1016         list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
1017                 run_nfsd4_cb(cb);
1018 }
1019
1020 static void nfsd4_do_callback_rpc(struct work_struct *w)
1021 {
1022         struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
1023         struct nfs4_client *clp = cb->cb_clp;
1024         struct rpc_clnt *clnt;
1025
1026         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1027                 nfsd4_process_cb_update(cb);
1028
1029         clnt = clp->cl_cb_client;
1030         if (!clnt) {
1031                 /* Callback channel broken, or client killed; give up: */
1032                 nfsd4_release_cb(cb);
1033                 return;
1034         }
1035         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1036         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1037                         cb->cb_ops, cb);
1038 }
1039
1040 void nfsd4_init_callback(struct nfsd4_callback *cb)
1041 {
1042         INIT_WORK(&cb->cb_work, nfsd4_do_callback_rpc);
1043 }
1044
1045 void nfsd4_cb_recall(struct nfs4_delegation *dp)
1046 {
1047         struct nfsd4_callback *cb = &dp->dl_recall;
1048         struct nfs4_client *clp = dp->dl_stid.sc_client;
1049
1050         dp->dl_retries = 1;
1051         cb->cb_op = dp;
1052         cb->cb_clp = clp;
1053         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1054         cb->cb_msg.rpc_argp = cb;
1055         cb->cb_msg.rpc_resp = cb;
1056
1057         cb->cb_ops = &nfsd4_cb_recall_ops;
1058
1059         INIT_LIST_HEAD(&cb->cb_per_client);
1060         cb->cb_done = true;
1061
1062         run_nfsd4_cb(&dp->dl_recall);
1063 }