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#include <uapi/linux/nfs2.h>
19
20#define NLMDBG_FACILITY		NLMDBG_XDR
21
22#if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
23#  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
24#endif
25
26/*
27 * Declare the space requirements for NLM arguments and replies as
28 * number of 32bit-words
29 */
30#define NLM_cookie_sz		(1+(NLM_MAXCOOKIELEN>>2))
31#define NLM_caller_sz		(1+(NLMCLNT_OHSIZE>>2))
32#define NLM_owner_sz		(1+(NLMCLNT_OHSIZE>>2))
33#define NLM_fhandle_sz		(1+(NFS2_FHSIZE>>2))
34#define NLM_lock_sz		(3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
35#define NLM_holder_sz		(4+NLM_owner_sz)
36
37#define NLM_testargs_sz		(NLM_cookie_sz+1+NLM_lock_sz)
38#define NLM_lockargs_sz		(NLM_cookie_sz+4+NLM_lock_sz)
39#define NLM_cancargs_sz		(NLM_cookie_sz+2+NLM_lock_sz)
40#define NLM_unlockargs_sz	(NLM_cookie_sz+NLM_lock_sz)
41
42#define NLM_testres_sz		(NLM_cookie_sz+1+NLM_holder_sz)
43#define NLM_res_sz		(NLM_cookie_sz+1)
44#define NLM_norep_sz		(0)
45
46
47static s32 loff_t_to_s32(loff_t offset)
48{
49	s32 res;
50
51	if (offset >= NLM_OFFSET_MAX)
52		res = NLM_OFFSET_MAX;
53	else if (offset <= -NLM_OFFSET_MAX)
54		res = -NLM_OFFSET_MAX;
55	else
56		res = offset;
57	return res;
58}
59
60static void nlm_compute_offsets(const struct nlm_lock *lock,
61				u32 *l_offset, u32 *l_len)
62{
63	const struct file_lock *fl = &lock->fl;
64
65	*l_offset = loff_t_to_s32(fl->fl_start);
66	if (fl->fl_end == OFFSET_MAX)
67		*l_len = 0;
68	else
69		*l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
70}
71
72/*
73 * Handle decode buffer overflows out-of-line.
74 */
75static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
76{
77	dprintk("lockd: %s prematurely hit the end of our receive buffer. "
78		"Remaining buffer length is %tu words.\n",
79		func, xdr->end - xdr->p);
80}
81
82
83/*
84 * Encode/decode NLMv3 basic data types
85 *
86 * Basic NLMv3 data types are not defined in an IETF standards
87 * document.  X/Open has a description of these data types that
88 * is useful.  See Chapter 10 of "Protocols for Interworking:
89 * XNFS, Version 3W".
90 *
91 * Not all basic data types have their own encoding and decoding
92 * functions.  For run-time efficiency, some data types are encoded
93 * or decoded inline.
94 */
95
96static void encode_bool(struct xdr_stream *xdr, const int value)
97{
98	__be32 *p;
99
100	p = xdr_reserve_space(xdr, 4);
101	*p = value ? xdr_one : xdr_zero;
102}
103
104static void encode_int32(struct xdr_stream *xdr, const s32 value)
105{
106	__be32 *p;
107
108	p = xdr_reserve_space(xdr, 4);
109	*p = cpu_to_be32(value);
110}
111
112/*
113 *	typedef opaque netobj<MAXNETOBJ_SZ>
114 */
115static void encode_netobj(struct xdr_stream *xdr,
116			  const u8 *data, const unsigned int length)
117{
118	__be32 *p;
119
120	p = xdr_reserve_space(xdr, 4 + length);
121	xdr_encode_opaque(p, data, length);
122}
123
124static int decode_netobj(struct xdr_stream *xdr,
125			 struct xdr_netobj *obj)
126{
127	u32 length;
128	__be32 *p;
129
130	p = xdr_inline_decode(xdr, 4);
131	if (unlikely(p == NULL))
132		goto out_overflow;
133	length = be32_to_cpup(p++);
134	if (unlikely(length > XDR_MAX_NETOBJ))
135		goto out_size;
136	obj->len = length;
137	obj->data = (u8 *)p;
138	return 0;
139out_size:
140	dprintk("NFS: returned netobj was too long: %u\n", length);
141	return -EIO;
142out_overflow:
143	print_overflow_msg(__func__, xdr);
144	return -EIO;
145}
146
147/*
148 *	netobj cookie;
149 */
150static void encode_cookie(struct xdr_stream *xdr,
151			  const struct nlm_cookie *cookie)
152{
153	encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
154}
155
156static int decode_cookie(struct xdr_stream *xdr,
157			 struct nlm_cookie *cookie)
158{
159	u32 length;
160	__be32 *p;
161
162	p = xdr_inline_decode(xdr, 4);
163	if (unlikely(p == NULL))
164		goto out_overflow;
165	length = be32_to_cpup(p++);
166	/* apparently HPUX can return empty cookies */
167	if (length == 0)
168		goto out_hpux;
169	if (length > NLM_MAXCOOKIELEN)
170		goto out_size;
171	p = xdr_inline_decode(xdr, length);
172	if (unlikely(p == NULL))
173		goto out_overflow;
174	cookie->len = length;
175	memcpy(cookie->data, p, length);
176	return 0;
177out_hpux:
178	cookie->len = 4;
179	memset(cookie->data, 0, 4);
180	return 0;
181out_size:
182	dprintk("NFS: returned cookie was too long: %u\n", length);
183	return -EIO;
184out_overflow:
185	print_overflow_msg(__func__, xdr);
186	return -EIO;
187}
188
189/*
190 *	netobj fh;
191 */
192static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
193{
194	encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
195}
196
197/*
198 *	enum nlm_stats {
199 *		LCK_GRANTED = 0,
200 *		LCK_DENIED = 1,
201 *		LCK_DENIED_NOLOCKS = 2,
202 *		LCK_BLOCKED = 3,
203 *		LCK_DENIED_GRACE_PERIOD = 4
204 *	};
205 *
206 *
207 *	struct nlm_stat {
208 *		nlm_stats stat;
209 *	};
210 *
211 * NB: we don't swap bytes for the NLM status values.  The upper
212 * layers deal directly with the status value in network byte
213 * order.
214 */
215
216static void encode_nlm_stat(struct xdr_stream *xdr,
217			    const __be32 stat)
218{
219	__be32 *p;
220
221	WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
222	p = xdr_reserve_space(xdr, 4);
223	*p = stat;
224}
225
226static int decode_nlm_stat(struct xdr_stream *xdr,
227			   __be32 *stat)
228{
229	__be32 *p;
230
231	p = xdr_inline_decode(xdr, 4);
232	if (unlikely(p == NULL))
233		goto out_overflow;
234	if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
235		goto out_enum;
236	*stat = *p;
237	return 0;
238out_enum:
239	dprintk("%s: server returned invalid nlm_stats value: %u\n",
240		__func__, be32_to_cpup(p));
241	return -EIO;
242out_overflow:
243	print_overflow_msg(__func__, xdr);
244	return -EIO;
245}
246
247/*
248 *	struct nlm_holder {
249 *		bool exclusive;
250 *		int uppid;
251 *		netobj oh;
252 *		unsigned l_offset;
253 *		unsigned l_len;
254 *	};
255 */
256static void encode_nlm_holder(struct xdr_stream *xdr,
257			      const struct nlm_res *result)
258{
259	const struct nlm_lock *lock = &result->lock;
260	u32 l_offset, l_len;
261	__be32 *p;
262
263	encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
264	encode_int32(xdr, lock->svid);
265	encode_netobj(xdr, lock->oh.data, lock->oh.len);
266
267	p = xdr_reserve_space(xdr, 4 + 4);
268	nlm_compute_offsets(lock, &l_offset, &l_len);
269	*p++ = cpu_to_be32(l_offset);
270	*p   = cpu_to_be32(l_len);
271}
272
273static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
274{
275	struct nlm_lock *lock = &result->lock;
276	struct file_lock *fl = &lock->fl;
277	u32 exclusive, l_offset, l_len;
278	int error;
279	__be32 *p;
280	s32 end;
281
282	memset(lock, 0, sizeof(*lock));
283	locks_init_lock(fl);
284
285	p = xdr_inline_decode(xdr, 4 + 4);
286	if (unlikely(p == NULL))
287		goto out_overflow;
288	exclusive = be32_to_cpup(p++);
289	lock->svid = be32_to_cpup(p);
290	fl->fl_pid = (pid_t)lock->svid;
291
292	error = decode_netobj(xdr, &lock->oh);
293	if (unlikely(error))
294		goto out;
295
296	p = xdr_inline_decode(xdr, 4 + 4);
297	if (unlikely(p == NULL))
298		goto out_overflow;
299
300	fl->fl_flags = FL_POSIX;
301	fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
302	l_offset = be32_to_cpup(p++);
303	l_len = be32_to_cpup(p);
304	end = l_offset + l_len - 1;
305
306	fl->fl_start = (loff_t)l_offset;
307	if (l_len == 0 || end < 0)
308		fl->fl_end = OFFSET_MAX;
309	else
310		fl->fl_end = (loff_t)end;
311	error = 0;
312out:
313	return error;
314out_overflow:
315	print_overflow_msg(__func__, xdr);
316	return -EIO;
317}
318
319/*
320 *	string caller_name<LM_MAXSTRLEN>;
321 */
322static void encode_caller_name(struct xdr_stream *xdr, const char *name)
323{
324	/* NB: client-side does not set lock->len */
325	u32 length = strlen(name);
326	__be32 *p;
327
328	p = xdr_reserve_space(xdr, 4 + length);
329	xdr_encode_opaque(p, name, length);
330}
331
332/*
333 *	struct nlm_lock {
334 *		string caller_name<LM_MAXSTRLEN>;
335 *		netobj fh;
336 *		netobj oh;
337 *		int uppid;
338 *		unsigned l_offset;
339 *		unsigned l_len;
340 *	};
341 */
342static void encode_nlm_lock(struct xdr_stream *xdr,
343			    const struct nlm_lock *lock)
344{
345	u32 l_offset, l_len;
346	__be32 *p;
347
348	encode_caller_name(xdr, lock->caller);
349	encode_fh(xdr, &lock->fh);
350	encode_netobj(xdr, lock->oh.data, lock->oh.len);
351
352	p = xdr_reserve_space(xdr, 4 + 4 + 4);
353	*p++ = cpu_to_be32(lock->svid);
354
355	nlm_compute_offsets(lock, &l_offset, &l_len);
356	*p++ = cpu_to_be32(l_offset);
357	*p   = cpu_to_be32(l_len);
358}
359
360
361/*
362 * NLMv3 XDR encode functions
363 *
364 * NLMv3 argument types are defined in Chapter 10 of The Open Group's
365 * "Protocols for Interworking: XNFS, Version 3W".
366 */
367
368/*
369 *	struct nlm_testargs {
370 *		netobj cookie;
371 *		bool exclusive;
372 *		struct nlm_lock alock;
373 *	};
374 */
375static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
376				 struct xdr_stream *xdr,
377				 const struct nlm_args *args)
378{
379	const struct nlm_lock *lock = &args->lock;
380
381	encode_cookie(xdr, &args->cookie);
382	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
383	encode_nlm_lock(xdr, lock);
384}
385
386/*
387 *	struct nlm_lockargs {
388 *		netobj cookie;
389 *		bool block;
390 *		bool exclusive;
391 *		struct nlm_lock alock;
392 *		bool reclaim;
393 *		int state;
394 *	};
395 */
396static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
397				 struct xdr_stream *xdr,
398				 const struct nlm_args *args)
399{
400	const struct nlm_lock *lock = &args->lock;
401
402	encode_cookie(xdr, &args->cookie);
403	encode_bool(xdr, args->block);
404	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
405	encode_nlm_lock(xdr, lock);
406	encode_bool(xdr, args->reclaim);
407	encode_int32(xdr, args->state);
408}
409
410/*
411 *	struct nlm_cancargs {
412 *		netobj cookie;
413 *		bool block;
414 *		bool exclusive;
415 *		struct nlm_lock alock;
416 *	};
417 */
418static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
419				 struct xdr_stream *xdr,
420				 const struct nlm_args *args)
421{
422	const struct nlm_lock *lock = &args->lock;
423
424	encode_cookie(xdr, &args->cookie);
425	encode_bool(xdr, args->block);
426	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
427	encode_nlm_lock(xdr, lock);
428}
429
430/*
431 *	struct nlm_unlockargs {
432 *		netobj cookie;
433 *		struct nlm_lock alock;
434 *	};
435 */
436static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
437				   struct xdr_stream *xdr,
438				   const struct nlm_args *args)
439{
440	const struct nlm_lock *lock = &args->lock;
441
442	encode_cookie(xdr, &args->cookie);
443	encode_nlm_lock(xdr, lock);
444}
445
446/*
447 *	struct nlm_res {
448 *		netobj cookie;
449 *		nlm_stat stat;
450 *	};
451 */
452static void nlm_xdr_enc_res(struct rpc_rqst *req,
453			    struct xdr_stream *xdr,
454			    const struct nlm_res *result)
455{
456	encode_cookie(xdr, &result->cookie);
457	encode_nlm_stat(xdr, result->status);
458}
459
460/*
461 *	union nlm_testrply switch (nlm_stats stat) {
462 *	case LCK_DENIED:
463 *		struct nlm_holder holder;
464 *	default:
465 *		void;
466 *	};
467 *
468 *	struct nlm_testres {
469 *		netobj cookie;
470 *		nlm_testrply test_stat;
471 *	};
472 */
473static void encode_nlm_testrply(struct xdr_stream *xdr,
474				const struct nlm_res *result)
475{
476	if (result->status == nlm_lck_denied)
477		encode_nlm_holder(xdr, result);
478}
479
480static void nlm_xdr_enc_testres(struct rpc_rqst *req,
481				struct xdr_stream *xdr,
482				const struct nlm_res *result)
483{
484	encode_cookie(xdr, &result->cookie);
485	encode_nlm_stat(xdr, result->status);
486	encode_nlm_testrply(xdr, result);
487}
488
489
490/*
491 * NLMv3 XDR decode functions
492 *
493 * NLMv3 result types are defined in Chapter 10 of The Open Group's
494 * "Protocols for Interworking: XNFS, Version 3W".
495 */
496
497/*
498 *	union nlm_testrply switch (nlm_stats stat) {
499 *	case LCK_DENIED:
500 *		struct nlm_holder holder;
501 *	default:
502 *		void;
503 *	};
504 *
505 *	struct nlm_testres {
506 *		netobj cookie;
507 *		nlm_testrply test_stat;
508 *	};
509 */
510static int decode_nlm_testrply(struct xdr_stream *xdr,
511			       struct nlm_res *result)
512{
513	int error;
514
515	error = decode_nlm_stat(xdr, &result->status);
516	if (unlikely(error))
517		goto out;
518	if (result->status == nlm_lck_denied)
519		error = decode_nlm_holder(xdr, result);
520out:
521	return error;
522}
523
524static int nlm_xdr_dec_testres(struct rpc_rqst *req,
525			       struct xdr_stream *xdr,
526			       struct nlm_res *result)
527{
528	int error;
529
530	error = decode_cookie(xdr, &result->cookie);
531	if (unlikely(error))
532		goto out;
533	error = decode_nlm_testrply(xdr, result);
534out:
535	return error;
536}
537
538/*
539 *	struct nlm_res {
540 *		netobj cookie;
541 *		nlm_stat stat;
542 *	};
543 */
544static int nlm_xdr_dec_res(struct rpc_rqst *req,
545			   struct xdr_stream *xdr,
546			   struct nlm_res *result)
547{
548	int error;
549
550	error = decode_cookie(xdr, &result->cookie);
551	if (unlikely(error))
552		goto out;
553	error = decode_nlm_stat(xdr, &result->status);
554out:
555	return error;
556}
557
558
559/*
560 * For NLM, a void procedure really returns nothing
561 */
562#define nlm_xdr_dec_norep	NULL
563
564#define PROC(proc, argtype, restype)	\
565[NLMPROC_##proc] = {							\
566	.p_proc      = NLMPROC_##proc,					\
567	.p_encode    = (kxdreproc_t)nlm_xdr_enc_##argtype,		\
568	.p_decode    = (kxdrdproc_t)nlm_xdr_dec_##restype,		\
569	.p_arglen    = NLM_##argtype##_sz,				\
570	.p_replen    = NLM_##restype##_sz,				\
571	.p_statidx   = NLMPROC_##proc,					\
572	.p_name      = #proc,						\
573	}
574
575static struct rpc_procinfo	nlm_procedures[] = {
576	PROC(TEST,		testargs,	testres),
577	PROC(LOCK,		lockargs,	res),
578	PROC(CANCEL,		cancargs,	res),
579	PROC(UNLOCK,		unlockargs,	res),
580	PROC(GRANTED,		testargs,	res),
581	PROC(TEST_MSG,		testargs,	norep),
582	PROC(LOCK_MSG,		lockargs,	norep),
583	PROC(CANCEL_MSG,	cancargs,	norep),
584	PROC(UNLOCK_MSG,	unlockargs,	norep),
585	PROC(GRANTED_MSG,	testargs,	norep),
586	PROC(TEST_RES,		testres,	norep),
587	PROC(LOCK_RES,		res,		norep),
588	PROC(CANCEL_RES,	res,		norep),
589	PROC(UNLOCK_RES,	res,		norep),
590	PROC(GRANTED_RES,	res,		norep),
591};
592
593static const struct rpc_version	nlm_version1 = {
594		.number		= 1,
595		.nrprocs	= ARRAY_SIZE(nlm_procedures),
596		.procs		= nlm_procedures,
597};
598
599static const struct rpc_version	nlm_version3 = {
600		.number		= 3,
601		.nrprocs	= ARRAY_SIZE(nlm_procedures),
602		.procs		= nlm_procedures,
603};
604
605static const struct rpc_version	*nlm_versions[] = {
606	[1] = &nlm_version1,
607	[3] = &nlm_version3,
608#ifdef CONFIG_LOCKD_V4
609	[4] = &nlm_version4,
610#endif
611};
612
613static struct rpc_stat		nlm_rpc_stats;
614
615const struct rpc_program	nlm_program = {
616		.name		= "lockd",
617		.number		= NLM_PROGRAM,
618		.nrvers		= ARRAY_SIZE(nlm_versions),
619		.version	= nlm_versions,
620		.stats		= &nlm_rpc_stats,
621};
622