nfsd4: move principal name into svc_cred
[linux-3.10.git] / 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 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
43
44 #define NFSPROC4_CB_NULL 0
45 #define NFSPROC4_CB_COMPOUND 1
46
47 /* Index of predefined Linux callback client operations */
48
49 enum {
50         NFSPROC4_CLNT_CB_NULL = 0,
51         NFSPROC4_CLNT_CB_RECALL,
52         NFSPROC4_CLNT_CB_SEQUENCE,
53 };
54
55 #define NFS4_MAXTAGLEN          20
56
57 #define NFS4_enc_cb_null_sz             0
58 #define NFS4_dec_cb_null_sz             0
59 #define cb_compound_enc_hdr_sz          4
60 #define cb_compound_dec_hdr_sz          (3 + (NFS4_MAXTAGLEN >> 2))
61 #define sessionid_sz                    (NFS4_MAX_SESSIONID_LEN >> 2)
62 #define cb_sequence_enc_sz              (sessionid_sz + 4 +             \
63                                         1 /* no referring calls list yet */)
64 #define cb_sequence_dec_sz              (op_dec_sz + sessionid_sz + 4)
65
66 #define op_enc_sz                       1
67 #define op_dec_sz                       2
68 #define enc_nfs4_fh_sz                  (1 + (NFS4_FHSIZE >> 2))
69 #define enc_stateid_sz                  (NFS4_STATEID_SIZE >> 2)
70 #define NFS4_enc_cb_recall_sz           (cb_compound_enc_hdr_sz +       \
71                                         cb_sequence_enc_sz +            \
72                                         1 + enc_stateid_sz +            \
73                                         enc_nfs4_fh_sz)
74
75 #define NFS4_dec_cb_recall_sz           (cb_compound_dec_hdr_sz  +      \
76                                         cb_sequence_dec_sz +            \
77                                         op_dec_sz)
78
79 struct nfs4_cb_compound_hdr {
80         /* args */
81         u32             ident;  /* minorversion 0 only */
82         u32             nops;
83         __be32          *nops_p;
84         u32             minorversion;
85         /* res */
86         int             status;
87 };
88
89 /*
90  * Handle decode buffer overflows out-of-line.
91  */
92 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
93 {
94         dprintk("NFS: %s prematurely hit the end of our receive buffer. "
95                 "Remaining buffer length is %tu words.\n",
96                 func, xdr->end - xdr->p);
97 }
98
99 static __be32 *xdr_encode_empty_array(__be32 *p)
100 {
101         *p++ = xdr_zero;
102         return p;
103 }
104
105 /*
106  * Encode/decode NFSv4 CB basic data types
107  *
108  * Basic NFSv4 callback data types are defined in section 15 of RFC
109  * 3530: "Network File System (NFS) version 4 Protocol" and section
110  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
111  * 1 Protocol"
112  */
113
114 /*
115  *      nfs_cb_opnum4
116  *
117  *      enum nfs_cb_opnum4 {
118  *              OP_CB_GETATTR           = 3,
119  *                ...
120  *      };
121  */
122 enum nfs_cb_opnum4 {
123         OP_CB_GETATTR                   = 3,
124         OP_CB_RECALL                    = 4,
125         OP_CB_LAYOUTRECALL              = 5,
126         OP_CB_NOTIFY                    = 6,
127         OP_CB_PUSH_DELEG                = 7,
128         OP_CB_RECALL_ANY                = 8,
129         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
130         OP_CB_RECALL_SLOT               = 10,
131         OP_CB_SEQUENCE                  = 11,
132         OP_CB_WANTS_CANCELLED           = 12,
133         OP_CB_NOTIFY_LOCK               = 13,
134         OP_CB_NOTIFY_DEVICEID           = 14,
135         OP_CB_ILLEGAL                   = 10044
136 };
137
138 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
139 {
140         __be32 *p;
141
142         p = xdr_reserve_space(xdr, 4);
143         *p = cpu_to_be32(op);
144 }
145
146 /*
147  * nfs_fh4
148  *
149  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
150  */
151 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
152 {
153         u32 length = fh->fh_size;
154         __be32 *p;
155
156         BUG_ON(length > NFS4_FHSIZE);
157         p = xdr_reserve_space(xdr, 4 + length);
158         xdr_encode_opaque(p, &fh->fh_base, length);
159 }
160
161 /*
162  * stateid4
163  *
164  *      struct stateid4 {
165  *              uint32_t        seqid;
166  *              opaque          other[12];
167  *      };
168  */
169 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
170 {
171         __be32 *p;
172
173         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
174         *p++ = cpu_to_be32(sid->si_generation);
175         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
176 }
177
178 /*
179  * sessionid4
180  *
181  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
182  */
183 static void encode_sessionid4(struct xdr_stream *xdr,
184                               const struct nfsd4_session *session)
185 {
186         __be32 *p;
187
188         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
189         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
190                                         NFS4_MAX_SESSIONID_LEN);
191 }
192
193 /*
194  * nfsstat4
195  */
196 static const struct {
197         int stat;
198         int errno;
199 } nfs_cb_errtbl[] = {
200         { NFS4_OK,              0               },
201         { NFS4ERR_PERM,         -EPERM          },
202         { NFS4ERR_NOENT,        -ENOENT         },
203         { NFS4ERR_IO,           -EIO            },
204         { NFS4ERR_NXIO,         -ENXIO          },
205         { NFS4ERR_ACCESS,       -EACCES         },
206         { NFS4ERR_EXIST,        -EEXIST         },
207         { NFS4ERR_XDEV,         -EXDEV          },
208         { NFS4ERR_NOTDIR,       -ENOTDIR        },
209         { NFS4ERR_ISDIR,        -EISDIR         },
210         { NFS4ERR_INVAL,        -EINVAL         },
211         { NFS4ERR_FBIG,         -EFBIG          },
212         { NFS4ERR_NOSPC,        -ENOSPC         },
213         { NFS4ERR_ROFS,         -EROFS          },
214         { NFS4ERR_MLINK,        -EMLINK         },
215         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
216         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
217         { NFS4ERR_DQUOT,        -EDQUOT         },
218         { NFS4ERR_STALE,        -ESTALE         },
219         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
220         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
221         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
222         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
223         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
224         { NFS4ERR_BADTYPE,      -EBADTYPE       },
225         { NFS4ERR_LOCKED,       -EAGAIN         },
226         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
227         { NFS4ERR_SYMLINK,      -ELOOP          },
228         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
229         { NFS4ERR_DEADLOCK,     -EDEADLK        },
230         { -1,                   -EIO            }
231 };
232
233 /*
234  * If we cannot translate the error, the recovery routines should
235  * handle it.
236  *
237  * Note: remaining NFSv4 error codes have values > 10000, so should
238  * not conflict with native Linux error codes.
239  */
240 static int nfs_cb_stat_to_errno(int status)
241 {
242         int i;
243
244         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
245                 if (nfs_cb_errtbl[i].stat == status)
246                         return nfs_cb_errtbl[i].errno;
247         }
248
249         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
250         return -status;
251 }
252
253 static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
254                                enum nfsstat4 *status)
255 {
256         __be32 *p;
257         u32 op;
258
259         p = xdr_inline_decode(xdr, 4 + 4);
260         if (unlikely(p == NULL))
261                 goto out_overflow;
262         op = be32_to_cpup(p++);
263         if (unlikely(op != expected))
264                 goto out_unexpected;
265         *status = be32_to_cpup(p);
266         return 0;
267 out_overflow:
268         print_overflow_msg(__func__, xdr);
269         return -EIO;
270 out_unexpected:
271         dprintk("NFSD: Callback server returned operation %d but "
272                 "we issued a request for %d\n", op, expected);
273         return -EIO;
274 }
275
276 /*
277  * CB_COMPOUND4args
278  *
279  *      struct CB_COMPOUND4args {
280  *              utf8str_cs      tag;
281  *              uint32_t        minorversion;
282  *              uint32_t        callback_ident;
283  *              nfs_cb_argop4   argarray<>;
284  *      };
285 */
286 static void encode_cb_compound4args(struct xdr_stream *xdr,
287                                     struct nfs4_cb_compound_hdr *hdr)
288 {
289         __be32 * p;
290
291         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
292         p = xdr_encode_empty_array(p);          /* empty tag */
293         *p++ = cpu_to_be32(hdr->minorversion);
294         *p++ = cpu_to_be32(hdr->ident);
295
296         hdr->nops_p = p;
297         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
298 }
299
300 /*
301  * Update argarray element count
302  */
303 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
304 {
305         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
306         *hdr->nops_p = cpu_to_be32(hdr->nops);
307 }
308
309 /*
310  * CB_COMPOUND4res
311  *
312  *      struct CB_COMPOUND4res {
313  *              nfsstat4        status;
314  *              utf8str_cs      tag;
315  *              nfs_cb_resop4   resarray<>;
316  *      };
317  */
318 static int decode_cb_compound4res(struct xdr_stream *xdr,
319                                   struct nfs4_cb_compound_hdr *hdr)
320 {
321         u32 length;
322         __be32 *p;
323
324         p = xdr_inline_decode(xdr, 4 + 4);
325         if (unlikely(p == NULL))
326                 goto out_overflow;
327         hdr->status = be32_to_cpup(p++);
328         /* Ignore the tag */
329         length = be32_to_cpup(p++);
330         p = xdr_inline_decode(xdr, length + 4);
331         if (unlikely(p == NULL))
332                 goto out_overflow;
333         hdr->nops = be32_to_cpup(p);
334         return 0;
335 out_overflow:
336         print_overflow_msg(__func__, xdr);
337         return -EIO;
338 }
339
340 /*
341  * CB_RECALL4args
342  *
343  *      struct CB_RECALL4args {
344  *              stateid4        stateid;
345  *              bool            truncate;
346  *              nfs_fh4         fh;
347  *      };
348  */
349 static void encode_cb_recall4args(struct xdr_stream *xdr,
350                                   const struct nfs4_delegation *dp,
351                                   struct nfs4_cb_compound_hdr *hdr)
352 {
353         __be32 *p;
354
355         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
356         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
357
358         p = xdr_reserve_space(xdr, 4);
359         *p++ = xdr_zero;                        /* truncate */
360
361         encode_nfs_fh4(xdr, &dp->dl_fh);
362
363         hdr->nops++;
364 }
365
366 /*
367  * CB_SEQUENCE4args
368  *
369  *      struct CB_SEQUENCE4args {
370  *              sessionid4              csa_sessionid;
371  *              sequenceid4             csa_sequenceid;
372  *              slotid4                 csa_slotid;
373  *              slotid4                 csa_highest_slotid;
374  *              bool                    csa_cachethis;
375  *              referring_call_list4    csa_referring_call_lists<>;
376  *      };
377  */
378 static void encode_cb_sequence4args(struct xdr_stream *xdr,
379                                     const struct nfsd4_callback *cb,
380                                     struct nfs4_cb_compound_hdr *hdr)
381 {
382         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
383         __be32 *p;
384
385         if (hdr->minorversion == 0)
386                 return;
387
388         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
389         encode_sessionid4(xdr, session);
390
391         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
392         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
393         *p++ = xdr_zero;                        /* csa_slotid */
394         *p++ = xdr_zero;                        /* csa_highest_slotid */
395         *p++ = xdr_zero;                        /* csa_cachethis */
396         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
397
398         hdr->nops++;
399 }
400
401 /*
402  * CB_SEQUENCE4resok
403  *
404  *      struct CB_SEQUENCE4resok {
405  *              sessionid4      csr_sessionid;
406  *              sequenceid4     csr_sequenceid;
407  *              slotid4         csr_slotid;
408  *              slotid4         csr_highest_slotid;
409  *              slotid4         csr_target_highest_slotid;
410  *      };
411  *
412  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
413  *      case NFS4_OK:
414  *              CB_SEQUENCE4resok       csr_resok4;
415  *      default:
416  *              void;
417  *      };
418  *
419  * Our current back channel implmentation supports a single backchannel
420  * with a single slot.
421  */
422 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
423                                     struct nfsd4_callback *cb)
424 {
425         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
426         struct nfs4_sessionid id;
427         int status;
428         __be32 *p;
429         u32 dummy;
430
431         status = -ESERVERFAULT;
432
433         /*
434          * If the server returns different values for sessionID, slotID or
435          * sequence number, the server is looney tunes.
436          */
437         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
438         if (unlikely(p == NULL))
439                 goto out_overflow;
440         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
441         if (memcmp(id.data, session->se_sessionid.data,
442                                         NFS4_MAX_SESSIONID_LEN) != 0) {
443                 dprintk("NFS: %s Invalid session id\n", __func__);
444                 goto out;
445         }
446         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
447
448         dummy = be32_to_cpup(p++);
449         if (dummy != session->se_cb_seq_nr) {
450                 dprintk("NFS: %s Invalid sequence number\n", __func__);
451                 goto out;
452         }
453
454         dummy = be32_to_cpup(p++);
455         if (dummy != 0) {
456                 dprintk("NFS: %s Invalid slotid\n", __func__);
457                 goto out;
458         }
459
460         /*
461          * FIXME: process highest slotid and target highest slotid
462          */
463         status = 0;
464 out:
465         if (status)
466                 nfsd4_mark_cb_fault(cb->cb_clp, status);
467         return status;
468 out_overflow:
469         print_overflow_msg(__func__, xdr);
470         return -EIO;
471 }
472
473 static int decode_cb_sequence4res(struct xdr_stream *xdr,
474                                   struct nfsd4_callback *cb)
475 {
476         enum nfsstat4 nfserr;
477         int status;
478
479         if (cb->cb_minorversion == 0)
480                 return 0;
481
482         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
483         if (unlikely(status))
484                 goto out;
485         if (unlikely(nfserr != NFS4_OK))
486                 goto out_default;
487         status = decode_cb_sequence4resok(xdr, cb);
488 out:
489         return status;
490 out_default:
491         return nfs_cb_stat_to_errno(nfserr);
492 }
493
494 /*
495  * NFSv4.0 and NFSv4.1 XDR encode functions
496  *
497  * NFSv4.0 callback argument types are defined in section 15 of RFC
498  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
499  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
500  * Protocol".
501  */
502
503 /*
504  * NB: Without this zero space reservation, callbacks over krb5p fail
505  */
506 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
507                                  void *__unused)
508 {
509         xdr_reserve_space(xdr, 0);
510 }
511
512 /*
513  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
514  */
515 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
516                                    const struct nfsd4_callback *cb)
517 {
518         const struct nfs4_delegation *args = cb->cb_op;
519         struct nfs4_cb_compound_hdr hdr = {
520                 .ident = cb->cb_clp->cl_cb_ident,
521                 .minorversion = cb->cb_minorversion,
522         };
523
524         encode_cb_compound4args(xdr, &hdr);
525         encode_cb_sequence4args(xdr, cb, &hdr);
526         encode_cb_recall4args(xdr, args, &hdr);
527         encode_cb_nops(&hdr);
528 }
529
530
531 /*
532  * NFSv4.0 and NFSv4.1 XDR decode functions
533  *
534  * NFSv4.0 callback result types are defined in section 15 of RFC
535  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
536  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
537  * Protocol".
538  */
539
540 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
541                                 void *__unused)
542 {
543         return 0;
544 }
545
546 /*
547  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
548  */
549 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
550                                   struct xdr_stream *xdr,
551                                   struct nfsd4_callback *cb)
552 {
553         struct nfs4_cb_compound_hdr hdr;
554         enum nfsstat4 nfserr;
555         int status;
556
557         status = decode_cb_compound4res(xdr, &hdr);
558         if (unlikely(status))
559                 goto out;
560
561         if (cb != NULL) {
562                 status = decode_cb_sequence4res(xdr, cb);
563                 if (unlikely(status))
564                         goto out;
565         }
566
567         status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
568         if (unlikely(status))
569                 goto out;
570         if (unlikely(nfserr != NFS4_OK))
571                 status = nfs_cb_stat_to_errno(nfserr);
572 out:
573         return status;
574 }
575
576 /*
577  * RPC procedure tables
578  */
579 #define PROC(proc, call, argtype, restype)                              \
580 [NFSPROC4_CLNT_##proc] = {                                              \
581         .p_proc    = NFSPROC4_CB_##call,                                \
582         .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
583         .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
584         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
585         .p_replen  = NFS4_dec_##restype##_sz,                           \
586         .p_statidx = NFSPROC4_CB_##call,                                \
587         .p_name    = #proc,                                             \
588 }
589
590 static struct rpc_procinfo nfs4_cb_procedures[] = {
591         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
592         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
593 };
594
595 static struct rpc_version nfs_cb_version4 = {
596 /*
597  * Note on the callback rpc program version number: despite language in rfc
598  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
599  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
600  * in practice that appears to be what implementations use.  The section
601  * 18.36.3 language is expected to be fixed in an erratum.
602  */
603         .number                 = 1,
604         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
605         .procs                  = nfs4_cb_procedures
606 };
607
608 static const struct rpc_version *nfs_cb_version[] = {
609         &nfs_cb_version4,
610 };
611
612 static const struct rpc_program cb_program;
613
614 static struct rpc_stat cb_stats = {
615         .program                = &cb_program
616 };
617
618 #define NFS4_CALLBACK 0x40000000
619 static const struct rpc_program cb_program = {
620         .name                   = "nfs4_cb",
621         .number                 = NFS4_CALLBACK,
622         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
623         .version                = nfs_cb_version,
624         .stats                  = &cb_stats,
625         .pipe_dir_name          = "nfsd4_cb",
626 };
627
628 static int max_cb_time(void)
629 {
630         return max(nfsd4_lease/10, (time_t)1) * HZ;
631 }
632
633
634 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
635 {
636         struct rpc_timeout      timeparms = {
637                 .to_initval     = max_cb_time(),
638                 .to_retries     = 0,
639         };
640         struct rpc_create_args args = {
641                 .net            = &init_net,
642                 .address        = (struct sockaddr *) &conn->cb_addr,
643                 .addrsize       = conn->cb_addrlen,
644                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
645                 .timeout        = &timeparms,
646                 .program        = &cb_program,
647                 .version        = 0,
648                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
649         };
650         struct rpc_clnt *client;
651
652         if (clp->cl_minorversion == 0) {
653                 if (!clp->cl_cred.cr_principal &&
654                                 (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
655                         return -EINVAL;
656                 args.client_name = clp->cl_cred.cr_principal;
657                 args.prognumber = conn->cb_prog,
658                 args.protocol = XPRT_TRANSPORT_TCP;
659                 args.authflavor = clp->cl_flavor;
660                 clp->cl_cb_ident = conn->cb_ident;
661         } else {
662                 if (!conn->cb_xprt)
663                         return -EINVAL;
664                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
665                 clp->cl_cb_session = ses;
666                 args.bc_xprt = conn->cb_xprt;
667                 args.prognumber = clp->cl_cb_session->se_cb_prog;
668                 args.protocol = XPRT_TRANSPORT_BC_TCP;
669                 args.authflavor = RPC_AUTH_UNIX;
670         }
671         /* Create RPC client */
672         client = rpc_create(&args);
673         if (IS_ERR(client)) {
674                 dprintk("NFSD: couldn't create callback client: %ld\n",
675                         PTR_ERR(client));
676                 return PTR_ERR(client);
677         }
678         clp->cl_cb_client = client;
679         return 0;
680
681 }
682
683 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
684 {
685         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
686                 (int)clp->cl_name.len, clp->cl_name.data, reason);
687 }
688
689 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
690 {
691         clp->cl_cb_state = NFSD4_CB_DOWN;
692         warn_no_callback_path(clp, reason);
693 }
694
695 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
696 {
697         clp->cl_cb_state = NFSD4_CB_FAULT;
698         warn_no_callback_path(clp, reason);
699 }
700
701 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
702 {
703         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
704
705         if (task->tk_status)
706                 nfsd4_mark_cb_down(clp, task->tk_status);
707         else
708                 clp->cl_cb_state = NFSD4_CB_UP;
709 }
710
711 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
712         /* XXX: release method to ensure we set the cb channel down if
713          * necessary on early failure? */
714         .rpc_call_done = nfsd4_cb_probe_done,
715 };
716
717 static struct rpc_cred *callback_cred;
718
719 int set_callback_cred(void)
720 {
721         if (callback_cred)
722                 return 0;
723         callback_cred = rpc_lookup_machine_cred("nfs");
724         if (!callback_cred)
725                 return -ENOMEM;
726         return 0;
727 }
728
729 static struct workqueue_struct *callback_wq;
730
731 static void run_nfsd4_cb(struct nfsd4_callback *cb)
732 {
733         queue_work(callback_wq, &cb->cb_work);
734 }
735
736 static void do_probe_callback(struct nfs4_client *clp)
737 {
738         struct nfsd4_callback *cb = &clp->cl_cb_null;
739
740         cb->cb_op = NULL;
741         cb->cb_clp = clp;
742
743         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
744         cb->cb_msg.rpc_argp = NULL;
745         cb->cb_msg.rpc_resp = NULL;
746         cb->cb_msg.rpc_cred = callback_cred;
747
748         cb->cb_ops = &nfsd4_cb_probe_ops;
749
750         run_nfsd4_cb(cb);
751 }
752
753 /*
754  * Poke the callback thread to process any updates to the callback
755  * parameters, and send a null probe.
756  */
757 void nfsd4_probe_callback(struct nfs4_client *clp)
758 {
759         /* XXX: atomicity?  Also, should we be using cl_flags? */
760         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
761         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
762         do_probe_callback(clp);
763 }
764
765 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
766 {
767         nfsd4_probe_callback(clp);
768         flush_workqueue(callback_wq);
769 }
770
771 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
772 {
773         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
774         spin_lock(&clp->cl_lock);
775         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
776         spin_unlock(&clp->cl_lock);
777 }
778
779 /*
780  * There's currently a single callback channel slot.
781  * If the slot is available, then mark it busy.  Otherwise, set the
782  * thread for sleeping on the callback RPC wait queue.
783  */
784 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
785 {
786         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
787                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
788                 dprintk("%s slot is busy\n", __func__);
789                 return false;
790         }
791         return true;
792 }
793
794 /*
795  * TODO: cb_sequence should support referring call lists, cachethis, multiple
796  * slots, and mark callback channel down on communication errors.
797  */
798 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
799 {
800         struct nfsd4_callback *cb = calldata;
801         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
802         struct nfs4_client *clp = dp->dl_stid.sc_client;
803         u32 minorversion = clp->cl_minorversion;
804
805         cb->cb_minorversion = minorversion;
806         if (minorversion) {
807                 if (!nfsd41_cb_get_slot(clp, task))
808                         return;
809         }
810         spin_lock(&clp->cl_lock);
811         if (list_empty(&cb->cb_per_client)) {
812                 /* This is the first call, not a restart */
813                 cb->cb_done = false;
814                 list_add(&cb->cb_per_client, &clp->cl_callbacks);
815         }
816         spin_unlock(&clp->cl_lock);
817         rpc_call_start(task);
818 }
819
820 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
821 {
822         struct nfsd4_callback *cb = calldata;
823         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
824         struct nfs4_client *clp = dp->dl_stid.sc_client;
825
826         dprintk("%s: minorversion=%d\n", __func__,
827                 clp->cl_minorversion);
828
829         if (clp->cl_minorversion) {
830                 /* No need for lock, access serialized in nfsd4_cb_prepare */
831                 ++clp->cl_cb_session->se_cb_seq_nr;
832                 clear_bit(0, &clp->cl_cb_slot_busy);
833                 rpc_wake_up_next(&clp->cl_cb_waitq);
834                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
835                         clp->cl_cb_session->se_cb_seq_nr);
836
837                 /* We're done looking into the sequence information */
838                 task->tk_msg.rpc_resp = NULL;
839         }
840 }
841
842
843 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
844 {
845         struct nfsd4_callback *cb = calldata;
846         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
847         struct nfs4_client *clp = dp->dl_stid.sc_client;
848         struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
849
850         nfsd4_cb_done(task, calldata);
851
852         if (current_rpc_client != task->tk_client) {
853                 /* We're shutting down or changing cl_cb_client; leave
854                  * it to nfsd4_process_cb_update to restart the call if
855                  * necessary. */
856                 return;
857         }
858
859         if (cb->cb_done)
860                 return;
861         switch (task->tk_status) {
862         case 0:
863                 cb->cb_done = true;
864                 return;
865         case -EBADHANDLE:
866         case -NFS4ERR_BAD_STATEID:
867                 /* Race: client probably got cb_recall
868                  * before open reply granting delegation */
869                 break;
870         default:
871                 /* Network partition? */
872                 nfsd4_mark_cb_down(clp, task->tk_status);
873         }
874         if (dp->dl_retries--) {
875                 rpc_delay(task, 2*HZ);
876                 task->tk_status = 0;
877                 rpc_restart_call_prepare(task);
878                 return;
879         }
880         nfsd4_mark_cb_down(clp, task->tk_status);
881         cb->cb_done = true;
882 }
883
884 static void nfsd4_cb_recall_release(void *calldata)
885 {
886         struct nfsd4_callback *cb = calldata;
887         struct nfs4_client *clp = cb->cb_clp;
888         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
889
890         if (cb->cb_done) {
891                 spin_lock(&clp->cl_lock);
892                 list_del(&cb->cb_per_client);
893                 spin_unlock(&clp->cl_lock);
894                 nfs4_put_delegation(dp);
895         }
896 }
897
898 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
899         .rpc_call_prepare = nfsd4_cb_prepare,
900         .rpc_call_done = nfsd4_cb_recall_done,
901         .rpc_release = nfsd4_cb_recall_release,
902 };
903
904 int nfsd4_create_callback_queue(void)
905 {
906         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
907         if (!callback_wq)
908                 return -ENOMEM;
909         return 0;
910 }
911
912 void nfsd4_destroy_callback_queue(void)
913 {
914         destroy_workqueue(callback_wq);
915 }
916
917 /* must be called under the state lock */
918 void nfsd4_shutdown_callback(struct nfs4_client *clp)
919 {
920         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
921         /*
922          * Note this won't actually result in a null callback;
923          * instead, nfsd4_do_callback_rpc() will detect the killed
924          * client, destroy the rpc client, and stop:
925          */
926         do_probe_callback(clp);
927         flush_workqueue(callback_wq);
928 }
929
930 static void nfsd4_release_cb(struct nfsd4_callback *cb)
931 {
932         if (cb->cb_ops->rpc_release)
933                 cb->cb_ops->rpc_release(cb);
934 }
935
936 /* requires cl_lock: */
937 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
938 {
939         struct nfsd4_session *s;
940         struct nfsd4_conn *c;
941
942         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
943                 list_for_each_entry(c, &s->se_conns, cn_persession) {
944                         if (c->cn_flags & NFS4_CDFC4_BACK)
945                                 return c;
946                 }
947         }
948         return NULL;
949 }
950
951 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
952 {
953         struct nfs4_cb_conn conn;
954         struct nfs4_client *clp = cb->cb_clp;
955         struct nfsd4_session *ses = NULL;
956         struct nfsd4_conn *c;
957         int err;
958
959         /*
960          * This is either an update, or the client dying; in either case,
961          * kill the old client:
962          */
963         if (clp->cl_cb_client) {
964                 rpc_shutdown_client(clp->cl_cb_client);
965                 clp->cl_cb_client = NULL;
966         }
967         if (clp->cl_cb_conn.cb_xprt) {
968                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
969                 clp->cl_cb_conn.cb_xprt = NULL;
970         }
971         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
972                 return;
973         spin_lock(&clp->cl_lock);
974         /*
975          * Only serialized callback code is allowed to clear these
976          * flags; main nfsd code can only set them:
977          */
978         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
979         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
980         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
981         c = __nfsd4_find_backchannel(clp);
982         if (c) {
983                 svc_xprt_get(c->cn_xprt);
984                 conn.cb_xprt = c->cn_xprt;
985                 ses = c->cn_session;
986         }
987         spin_unlock(&clp->cl_lock);
988
989         err = setup_callback_client(clp, &conn, ses);
990         if (err) {
991                 nfsd4_mark_cb_down(clp, err);
992                 return;
993         }
994         /* Yay, the callback channel's back! Restart any callbacks: */
995         list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
996                 run_nfsd4_cb(cb);
997 }
998
999 void nfsd4_do_callback_rpc(struct work_struct *w)
1000 {
1001         struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
1002         struct nfs4_client *clp = cb->cb_clp;
1003         struct rpc_clnt *clnt;
1004
1005         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1006                 nfsd4_process_cb_update(cb);
1007
1008         clnt = clp->cl_cb_client;
1009         if (!clnt) {
1010                 /* Callback channel broken, or client killed; give up: */
1011                 nfsd4_release_cb(cb);
1012                 return;
1013         }
1014         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1015                         cb->cb_ops, cb);
1016 }
1017
1018 void nfsd4_cb_recall(struct nfs4_delegation *dp)
1019 {
1020         struct nfsd4_callback *cb = &dp->dl_recall;
1021         struct nfs4_client *clp = dp->dl_stid.sc_client;
1022
1023         dp->dl_retries = 1;
1024         cb->cb_op = dp;
1025         cb->cb_clp = clp;
1026         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1027         cb->cb_msg.rpc_argp = cb;
1028         cb->cb_msg.rpc_resp = cb;
1029         cb->cb_msg.rpc_cred = callback_cred;
1030
1031         cb->cb_ops = &nfsd4_cb_recall_ops;
1032         dp->dl_retries = 1;
1033
1034         INIT_LIST_HEAD(&cb->cb_per_client);
1035         cb->cb_done = true;
1036
1037         run_nfsd4_cb(&dp->dl_recall);
1038 }