Root/fs/lockd/clntxdr.c

1/*
2 * linux/fs/lockd/clntxdr.c
3 *
4 * XDR functions to encode/decode NLM version 3 RPC arguments and results.
5 * NLM version 3 is backwards compatible with NLM versions 1 and 2.
6 *
7 * NLM client-side only.
8 *
9 * Copyright (C) 2010, Oracle. All rights reserved.
10 */
11
12#include <linux/types.h>
13#include <linux/sunrpc/xdr.h>
14#include <linux/sunrpc/clnt.h>
15#include <linux/sunrpc/stats.h>
16#include <linux/lockd/lockd.h>
17
18#define NLMDBG_FACILITY NLMDBG_XDR
19
20#if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
21# error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
22#endif
23
24/*
25 * Declare the space requirements for NLM arguments and replies as
26 * number of 32bit-words
27 */
28#define NLM_cookie_sz (1+(NLM_MAXCOOKIELEN>>2))
29#define NLM_caller_sz (1+(NLMCLNT_OHSIZE>>2))
30#define NLM_owner_sz (1+(NLMCLNT_OHSIZE>>2))
31#define NLM_fhandle_sz (1+(NFS2_FHSIZE>>2))
32#define NLM_lock_sz (3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
33#define NLM_holder_sz (4+NLM_owner_sz)
34
35#define NLM_testargs_sz (NLM_cookie_sz+1+NLM_lock_sz)
36#define NLM_lockargs_sz (NLM_cookie_sz+4+NLM_lock_sz)
37#define NLM_cancargs_sz (NLM_cookie_sz+2+NLM_lock_sz)
38#define NLM_unlockargs_sz (NLM_cookie_sz+NLM_lock_sz)
39
40#define NLM_testres_sz (NLM_cookie_sz+1+NLM_holder_sz)
41#define NLM_res_sz (NLM_cookie_sz+1)
42#define NLM_norep_sz (0)
43
44
45static s32 loff_t_to_s32(loff_t offset)
46{
47    s32 res;
48
49    if (offset >= NLM_OFFSET_MAX)
50        res = NLM_OFFSET_MAX;
51    else if (offset <= -NLM_OFFSET_MAX)
52        res = -NLM_OFFSET_MAX;
53    else
54        res = offset;
55    return res;
56}
57
58static void nlm_compute_offsets(const struct nlm_lock *lock,
59                u32 *l_offset, u32 *l_len)
60{
61    const struct file_lock *fl = &lock->fl;
62
63    BUG_ON(fl->fl_start > NLM_OFFSET_MAX);
64    BUG_ON(fl->fl_end > NLM_OFFSET_MAX &&
65                fl->fl_end != OFFSET_MAX);
66
67    *l_offset = loff_t_to_s32(fl->fl_start);
68    if (fl->fl_end == OFFSET_MAX)
69        *l_len = 0;
70    else
71        *l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
72}
73
74/*
75 * Handle decode buffer overflows out-of-line.
76 */
77static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
78{
79    dprintk("lockd: %s prematurely hit the end of our receive buffer. "
80        "Remaining buffer length is %tu words.\n",
81        func, xdr->end - xdr->p);
82}
83
84
85/*
86 * Encode/decode NLMv3 basic data types
87 *
88 * Basic NLMv3 data types are not defined in an IETF standards
89 * document. X/Open has a description of these data types that
90 * is useful. See Chapter 10 of "Protocols for Interworking:
91 * XNFS, Version 3W".
92 *
93 * Not all basic data types have their own encoding and decoding
94 * functions. For run-time efficiency, some data types are encoded
95 * or decoded inline.
96 */
97
98static void encode_bool(struct xdr_stream *xdr, const int value)
99{
100    __be32 *p;
101
102    p = xdr_reserve_space(xdr, 4);
103    *p = value ? xdr_one : xdr_zero;
104}
105
106static void encode_int32(struct xdr_stream *xdr, const s32 value)
107{
108    __be32 *p;
109
110    p = xdr_reserve_space(xdr, 4);
111    *p = cpu_to_be32(value);
112}
113
114/*
115 * typedef opaque netobj<MAXNETOBJ_SZ>
116 */
117static void encode_netobj(struct xdr_stream *xdr,
118              const u8 *data, const unsigned int length)
119{
120    __be32 *p;
121
122    BUG_ON(length > XDR_MAX_NETOBJ);
123    p = xdr_reserve_space(xdr, 4 + length);
124    xdr_encode_opaque(p, data, length);
125}
126
127static int decode_netobj(struct xdr_stream *xdr,
128             struct xdr_netobj *obj)
129{
130    u32 length;
131    __be32 *p;
132
133    p = xdr_inline_decode(xdr, 4);
134    if (unlikely(p == NULL))
135        goto out_overflow;
136    length = be32_to_cpup(p++);
137    if (unlikely(length > XDR_MAX_NETOBJ))
138        goto out_size;
139    obj->len = length;
140    obj->data = (u8 *)p;
141    return 0;
142out_size:
143    dprintk("NFS: returned netobj was too long: %u\n", length);
144    return -EIO;
145out_overflow:
146    print_overflow_msg(__func__, xdr);
147    return -EIO;
148}
149
150/*
151 * netobj cookie;
152 */
153static void encode_cookie(struct xdr_stream *xdr,
154              const struct nlm_cookie *cookie)
155{
156    BUG_ON(cookie->len > NLM_MAXCOOKIELEN);
157    encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
158}
159
160static int decode_cookie(struct xdr_stream *xdr,
161             struct nlm_cookie *cookie)
162{
163    u32 length;
164    __be32 *p;
165
166    p = xdr_inline_decode(xdr, 4);
167    if (unlikely(p == NULL))
168        goto out_overflow;
169    length = be32_to_cpup(p++);
170    /* apparently HPUX can return empty cookies */
171    if (length == 0)
172        goto out_hpux;
173    if (length > NLM_MAXCOOKIELEN)
174        goto out_size;
175    p = xdr_inline_decode(xdr, length);
176    if (unlikely(p == NULL))
177        goto out_overflow;
178    cookie->len = length;
179    memcpy(cookie->data, p, length);
180    return 0;
181out_hpux:
182    cookie->len = 4;
183    memset(cookie->data, 0, 4);
184    return 0;
185out_size:
186    dprintk("NFS: returned cookie was too long: %u\n", length);
187    return -EIO;
188out_overflow:
189    print_overflow_msg(__func__, xdr);
190    return -EIO;
191}
192
193/*
194 * netobj fh;
195 */
196static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
197{
198    BUG_ON(fh->size != NFS2_FHSIZE);
199    encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
200}
201
202/*
203 * enum nlm_stats {
204 * LCK_GRANTED = 0,
205 * LCK_DENIED = 1,
206 * LCK_DENIED_NOLOCKS = 2,
207 * LCK_BLOCKED = 3,
208 * LCK_DENIED_GRACE_PERIOD = 4
209 * };
210 *
211 *
212 * struct nlm_stat {
213 * nlm_stats stat;
214 * };
215 *
216 * NB: we don't swap bytes for the NLM status values. The upper
217 * layers deal directly with the status value in network byte
218 * order.
219 */
220
221static void encode_nlm_stat(struct xdr_stream *xdr,
222                const __be32 stat)
223{
224    __be32 *p;
225
226    BUG_ON(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
227    p = xdr_reserve_space(xdr, 4);
228    *p = stat;
229}
230
231static int decode_nlm_stat(struct xdr_stream *xdr,
232               __be32 *stat)
233{
234    __be32 *p;
235
236    p = xdr_inline_decode(xdr, 4);
237    if (unlikely(p == NULL))
238        goto out_overflow;
239    if (unlikely(*p > nlm_lck_denied_grace_period))
240        goto out_enum;
241    *stat = *p;
242    return 0;
243out_enum:
244    dprintk("%s: server returned invalid nlm_stats value: %u\n",
245        __func__, be32_to_cpup(p));
246    return -EIO;
247out_overflow:
248    print_overflow_msg(__func__, xdr);
249    return -EIO;
250}
251
252/*
253 * struct nlm_holder {
254 * bool exclusive;
255 * int uppid;
256 * netobj oh;
257 * unsigned l_offset;
258 * unsigned l_len;
259 * };
260 */
261static void encode_nlm_holder(struct xdr_stream *xdr,
262                  const struct nlm_res *result)
263{
264    const struct nlm_lock *lock = &result->lock;
265    u32 l_offset, l_len;
266    __be32 *p;
267
268    encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
269    encode_int32(xdr, lock->svid);
270    encode_netobj(xdr, lock->oh.data, lock->oh.len);
271
272    p = xdr_reserve_space(xdr, 4 + 4);
273    nlm_compute_offsets(lock, &l_offset, &l_len);
274    *p++ = cpu_to_be32(l_offset);
275    *p = cpu_to_be32(l_len);
276}
277
278static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
279{
280    struct nlm_lock *lock = &result->lock;
281    struct file_lock *fl = &lock->fl;
282    u32 exclusive, l_offset, l_len;
283    int error;
284    __be32 *p;
285    s32 end;
286
287    memset(lock, 0, sizeof(*lock));
288    locks_init_lock(fl);
289
290    p = xdr_inline_decode(xdr, 4 + 4);
291    if (unlikely(p == NULL))
292        goto out_overflow;
293    exclusive = be32_to_cpup(p++);
294    lock->svid = be32_to_cpup(p);
295    fl->fl_pid = (pid_t)lock->svid;
296
297    error = decode_netobj(xdr, &lock->oh);
298    if (unlikely(error))
299        goto out;
300
301    p = xdr_inline_decode(xdr, 4 + 4);
302    if (unlikely(p == NULL))
303        goto out_overflow;
304
305    fl->fl_flags = FL_POSIX;
306    fl->fl_type = exclusive != 0 ? F_WRLCK : F_RDLCK;
307    l_offset = be32_to_cpup(p++);
308    l_len = be32_to_cpup(p);
309    end = l_offset + l_len - 1;
310
311    fl->fl_start = (loff_t)l_offset;
312    if (l_len == 0 || end < 0)
313        fl->fl_end = OFFSET_MAX;
314    else
315        fl->fl_end = (loff_t)end;
316    error = 0;
317out:
318    return error;
319out_overflow:
320    print_overflow_msg(__func__, xdr);
321    return -EIO;
322}
323
324/*
325 * string caller_name<LM_MAXSTRLEN>;
326 */
327static void encode_caller_name(struct xdr_stream *xdr, const char *name)
328{
329    /* NB: client-side does not set lock->len */
330    u32 length = strlen(name);
331    __be32 *p;
332
333    BUG_ON(length > NLM_MAXSTRLEN);
334    p = xdr_reserve_space(xdr, 4 + length);
335    xdr_encode_opaque(p, name, length);
336}
337
338/*
339 * struct nlm_lock {
340 * string caller_name<LM_MAXSTRLEN>;
341 * netobj fh;
342 * netobj oh;
343 * int uppid;
344 * unsigned l_offset;
345 * unsigned l_len;
346 * };
347 */
348static void encode_nlm_lock(struct xdr_stream *xdr,
349                const struct nlm_lock *lock)
350{
351    u32 l_offset, l_len;
352    __be32 *p;
353
354    encode_caller_name(xdr, lock->caller);
355    encode_fh(xdr, &lock->fh);
356    encode_netobj(xdr, lock->oh.data, lock->oh.len);
357
358    p = xdr_reserve_space(xdr, 4 + 4 + 4);
359    *p++ = cpu_to_be32(lock->svid);
360
361    nlm_compute_offsets(lock, &l_offset, &l_len);
362    *p++ = cpu_to_be32(l_offset);
363    *p = cpu_to_be32(l_len);
364}
365
366
367/*
368 * NLMv3 XDR encode functions
369 *
370 * NLMv3 argument types are defined in Chapter 10 of The Open Group's
371 * "Protocols for Interworking: XNFS, Version 3W".
372 */
373
374/*
375 * struct nlm_testargs {
376 * netobj cookie;
377 * bool exclusive;
378 * struct nlm_lock alock;
379 * };
380 */
381static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
382                 struct xdr_stream *xdr,
383                 const struct nlm_args *args)
384{
385    const struct nlm_lock *lock = &args->lock;
386
387    encode_cookie(xdr, &args->cookie);
388    encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
389    encode_nlm_lock(xdr, lock);
390}
391
392/*
393 * struct nlm_lockargs {
394 * netobj cookie;
395 * bool block;
396 * bool exclusive;
397 * struct nlm_lock alock;
398 * bool reclaim;
399 * int state;
400 * };
401 */
402static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
403                 struct xdr_stream *xdr,
404                 const struct nlm_args *args)
405{
406    const struct nlm_lock *lock = &args->lock;
407
408    encode_cookie(xdr, &args->cookie);
409    encode_bool(xdr, args->block);
410    encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
411    encode_nlm_lock(xdr, lock);
412    encode_bool(xdr, args->reclaim);
413    encode_int32(xdr, args->state);
414}
415
416/*
417 * struct nlm_cancargs {
418 * netobj cookie;
419 * bool block;
420 * bool exclusive;
421 * struct nlm_lock alock;
422 * };
423 */
424static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
425                 struct xdr_stream *xdr,
426                 const struct nlm_args *args)
427{
428    const struct nlm_lock *lock = &args->lock;
429
430    encode_cookie(xdr, &args->cookie);
431    encode_bool(xdr, args->block);
432    encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
433    encode_nlm_lock(xdr, lock);
434}
435
436/*
437 * struct nlm_unlockargs {
438 * netobj cookie;
439 * struct nlm_lock alock;
440 * };
441 */
442static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
443                   struct xdr_stream *xdr,
444                   const struct nlm_args *args)
445{
446    const struct nlm_lock *lock = &args->lock;
447
448    encode_cookie(xdr, &args->cookie);
449    encode_nlm_lock(xdr, lock);
450}
451
452/*
453 * struct nlm_res {
454 * netobj cookie;
455 * nlm_stat stat;
456 * };
457 */
458static void nlm_xdr_enc_res(struct rpc_rqst *req,
459                struct xdr_stream *xdr,
460                const struct nlm_res *result)
461{
462    encode_cookie(xdr, &result->cookie);
463    encode_nlm_stat(xdr, result->status);
464}
465
466/*
467 * union nlm_testrply switch (nlm_stats stat) {
468 * case LCK_DENIED:
469 * struct nlm_holder holder;
470 * default:
471 * void;
472 * };
473 *
474 * struct nlm_testres {
475 * netobj cookie;
476 * nlm_testrply test_stat;
477 * };
478 */
479static void encode_nlm_testrply(struct xdr_stream *xdr,
480                const struct nlm_res *result)
481{
482    if (result->status == nlm_lck_denied)
483        encode_nlm_holder(xdr, result);
484}
485
486static void nlm_xdr_enc_testres(struct rpc_rqst *req,
487                struct xdr_stream *xdr,
488                const struct nlm_res *result)
489{
490    encode_cookie(xdr, &result->cookie);
491    encode_nlm_stat(xdr, result->status);
492    encode_nlm_testrply(xdr, result);
493}
494
495
496/*
497 * NLMv3 XDR decode functions
498 *
499 * NLMv3 result types are defined in Chapter 10 of The Open Group's
500 * "Protocols for Interworking: XNFS, Version 3W".
501 */
502
503/*
504 * union nlm_testrply switch (nlm_stats stat) {
505 * case LCK_DENIED:
506 * struct nlm_holder holder;
507 * default:
508 * void;
509 * };
510 *
511 * struct nlm_testres {
512 * netobj cookie;
513 * nlm_testrply test_stat;
514 * };
515 */
516static int decode_nlm_testrply(struct xdr_stream *xdr,
517                   struct nlm_res *result)
518{
519    int error;
520
521    error = decode_nlm_stat(xdr, &result->status);
522    if (unlikely(error))
523        goto out;
524    if (result->status == nlm_lck_denied)
525        error = decode_nlm_holder(xdr, result);
526out:
527    return error;
528}
529
530static int nlm_xdr_dec_testres(struct rpc_rqst *req,
531                   struct xdr_stream *xdr,
532                   struct nlm_res *result)
533{
534    int error;
535
536    error = decode_cookie(xdr, &result->cookie);
537    if (unlikely(error))
538        goto out;
539    error = decode_nlm_testrply(xdr, result);
540out:
541    return error;
542}
543
544/*
545 * struct nlm_res {
546 * netobj cookie;
547 * nlm_stat stat;
548 * };
549 */
550static int nlm_xdr_dec_res(struct rpc_rqst *req,
551               struct xdr_stream *xdr,
552               struct nlm_res *result)
553{
554    int error;
555
556    error = decode_cookie(xdr, &result->cookie);
557    if (unlikely(error))
558        goto out;
559    error = decode_nlm_stat(xdr, &result->status);
560out:
561    return error;
562}
563
564
565/*
566 * For NLM, a void procedure really returns nothing
567 */
568#define nlm_xdr_dec_norep NULL
569
570#define PROC(proc, argtype, restype) \
571[NLMPROC_##proc] = { \
572    .p_proc = NLMPROC_##proc, \
573    .p_encode = (kxdreproc_t)nlm_xdr_enc_##argtype, \
574    .p_decode = (kxdrdproc_t)nlm_xdr_dec_##restype, \
575    .p_arglen = NLM_##argtype##_sz, \
576    .p_replen = NLM_##restype##_sz, \
577    .p_statidx = NLMPROC_##proc, \
578    .p_name = #proc, \
579    }
580
581static struct rpc_procinfo nlm_procedures[] = {
582    PROC(TEST, testargs, testres),
583    PROC(LOCK, lockargs, res),
584    PROC(CANCEL, cancargs, res),
585    PROC(UNLOCK, unlockargs, res),
586    PROC(GRANTED, testargs, res),
587    PROC(TEST_MSG, testargs, norep),
588    PROC(LOCK_MSG, lockargs, norep),
589    PROC(CANCEL_MSG, cancargs, norep),
590    PROC(UNLOCK_MSG, unlockargs, norep),
591    PROC(GRANTED_MSG, testargs, norep),
592    PROC(TEST_RES, testres, norep),
593    PROC(LOCK_RES, res, norep),
594    PROC(CANCEL_RES, res, norep),
595    PROC(UNLOCK_RES, res, norep),
596    PROC(GRANTED_RES, res, norep),
597};
598
599static struct rpc_version nlm_version1 = {
600        .number = 1,
601        .nrprocs = ARRAY_SIZE(nlm_procedures),
602        .procs = nlm_procedures,
603};
604
605static struct rpc_version nlm_version3 = {
606        .number = 3,
607        .nrprocs = ARRAY_SIZE(nlm_procedures),
608        .procs = nlm_procedures,
609};
610
611static struct rpc_version *nlm_versions[] = {
612    [1] = &nlm_version1,
613    [3] = &nlm_version3,
614#ifdef CONFIG_LOCKD_V4
615    [4] = &nlm_version4,
616#endif
617};
618
619static struct rpc_stat nlm_rpc_stats;
620
621struct rpc_program nlm_program = {
622        .name = "lockd",
623        .number = NLM_PROGRAM,
624        .nrvers = ARRAY_SIZE(nlm_versions),
625        .version = nlm_versions,
626        .stats = &nlm_rpc_stats,
627};
628

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