xref: /openbmc/linux/fs/lockd/clnt4xdr.c (revision 861e10be) 
1 /*
2  * linux/fs/lockd/clnt4xdr.c
3  *
4  * XDR functions to encode/decode NLM version 4 RPC arguments and results.
5  *
6  * NLM client-side only.
7  *
8  * Copyright (C) 2010, Oracle.  All rights reserved.
9  */
10 
11 #include <linux/types.h>
12 #include <linux/sunrpc/xdr.h>
13 #include <linux/sunrpc/clnt.h>
14 #include <linux/sunrpc/stats.h>
15 #include <linux/lockd/lockd.h>
16 
17 #define NLMDBG_FACILITY		NLMDBG_XDR
18 
19 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
20 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
21 #endif
22 
23 #if (NLMCLNT_OHSIZE > NLM_MAXSTRLEN)
24 #  error "NLM host name cannot be larger than NLM's maximum string length!"
25 #endif
26 
27 /*
28  * Declare the space requirements for NLM arguments and replies as
29  * number of 32bit-words
30  */
31 #define NLM4_void_sz		(0)
32 #define NLM4_cookie_sz		(1+(NLM_MAXCOOKIELEN>>2))
33 #define NLM4_caller_sz		(1+(NLMCLNT_OHSIZE>>2))
34 #define NLM4_owner_sz		(1+(NLMCLNT_OHSIZE>>2))
35 #define NLM4_fhandle_sz		(1+(NFS3_FHSIZE>>2))
36 #define NLM4_lock_sz		(5+NLM4_caller_sz+NLM4_owner_sz+NLM4_fhandle_sz)
37 #define NLM4_holder_sz		(6+NLM4_owner_sz)
38 
39 #define NLM4_testargs_sz	(NLM4_cookie_sz+1+NLM4_lock_sz)
40 #define NLM4_lockargs_sz	(NLM4_cookie_sz+4+NLM4_lock_sz)
41 #define NLM4_cancargs_sz	(NLM4_cookie_sz+2+NLM4_lock_sz)
42 #define NLM4_unlockargs_sz	(NLM4_cookie_sz+NLM4_lock_sz)
43 
44 #define NLM4_testres_sz		(NLM4_cookie_sz+1+NLM4_holder_sz)
45 #define NLM4_res_sz		(NLM4_cookie_sz+1)
46 #define NLM4_norep_sz		(0)
47 
48 
49 static s64 loff_t_to_s64(loff_t offset)
50 {
51 	s64 res;
52 
53 	if (offset >= NLM4_OFFSET_MAX)
54 		res = NLM4_OFFSET_MAX;
55 	else if (offset <= -NLM4_OFFSET_MAX)
56 		res = -NLM4_OFFSET_MAX;
57 	else
58 		res = offset;
59 	return res;
60 }
61 
62 static void nlm4_compute_offsets(const struct nlm_lock *lock,
63 				 u64 *l_offset, u64 *l_len)
64 {
65 	const struct file_lock *fl = &lock->fl;
66 
67 	*l_offset = loff_t_to_s64(fl->fl_start);
68 	if (fl->fl_end == OFFSET_MAX)
69 		*l_len = 0;
70 	else
71 		*l_len = loff_t_to_s64(fl->fl_end - fl->fl_start + 1);
72 }
73 
74 /*
75  * Handle decode buffer overflows out-of-line.
76  */
77 static 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 NLMv4 basic data types
87  *
88  * Basic NLMv4 data types are defined in Appendix II, section 6.1.4
89  * of RFC 1813: "NFS Version 3 Protocol Specification" and in Chapter
90  * 10 of X/Open's "Protocols for Interworking: XNFS, Version 3W".
91  *
92  * Not all basic data types have their own encoding and decoding
93  * functions.  For run-time efficiency, some data types are encoded
94  * or decoded inline.
95  */
96 
97 static void encode_bool(struct xdr_stream *xdr, const int value)
98 {
99 	__be32 *p;
100 
101 	p = xdr_reserve_space(xdr, 4);
102 	*p = value ? xdr_one : xdr_zero;
103 }
104 
105 static void encode_int32(struct xdr_stream *xdr, const s32 value)
106 {
107 	__be32 *p;
108 
109 	p = xdr_reserve_space(xdr, 4);
110 	*p = cpu_to_be32(value);
111 }
112 
113 /*
114  *	typedef opaque netobj<MAXNETOBJ_SZ>
115  */
116 static void encode_netobj(struct xdr_stream *xdr,
117 			  const u8 *data, const unsigned int length)
118 {
119 	__be32 *p;
120 
121 	p = xdr_reserve_space(xdr, 4 + length);
122 	xdr_encode_opaque(p, data, length);
123 }
124 
125 static int decode_netobj(struct xdr_stream *xdr,
126 			 struct xdr_netobj *obj)
127 {
128 	u32 length;
129 	__be32 *p;
130 
131 	p = xdr_inline_decode(xdr, 4);
132 	if (unlikely(p == NULL))
133 		goto out_overflow;
134 	length = be32_to_cpup(p++);
135 	if (unlikely(length > XDR_MAX_NETOBJ))
136 		goto out_size;
137 	obj->len = length;
138 	obj->data = (u8 *)p;
139 	return 0;
140 out_size:
141 	dprintk("NFS: returned netobj was too long: %u\n", length);
142 	return -EIO;
143 out_overflow:
144 	print_overflow_msg(__func__, xdr);
145 	return -EIO;
146 }
147 
148 /*
149  *	netobj cookie;
150  */
151 static void encode_cookie(struct xdr_stream *xdr,
152 			  const struct nlm_cookie *cookie)
153 {
154 	encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
155 }
156 
157 static int decode_cookie(struct xdr_stream *xdr,
158 			     struct nlm_cookie *cookie)
159 {
160 	u32 length;
161 	__be32 *p;
162 
163 	p = xdr_inline_decode(xdr, 4);
164 	if (unlikely(p == NULL))
165 		goto out_overflow;
166 	length = be32_to_cpup(p++);
167 	/* apparently HPUX can return empty cookies */
168 	if (length == 0)
169 		goto out_hpux;
170 	if (length > NLM_MAXCOOKIELEN)
171 		goto out_size;
172 	p = xdr_inline_decode(xdr, length);
173 	if (unlikely(p == NULL))
174 		goto out_overflow;
175 	cookie->len = length;
176 	memcpy(cookie->data, p, length);
177 	return 0;
178 out_hpux:
179 	cookie->len = 4;
180 	memset(cookie->data, 0, 4);
181 	return 0;
182 out_size:
183 	dprintk("NFS: returned cookie was too long: %u\n", length);
184 	return -EIO;
185 out_overflow:
186 	print_overflow_msg(__func__, xdr);
187 	return -EIO;
188 }
189 
190 /*
191  *	netobj fh;
192  */
193 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
194 {
195 	encode_netobj(xdr, (u8 *)&fh->data, fh->size);
196 }
197 
198 /*
199  *	enum nlm4_stats {
200  *		NLM4_GRANTED = 0,
201  *		NLM4_DENIED = 1,
202  *		NLM4_DENIED_NOLOCKS = 2,
203  *		NLM4_BLOCKED = 3,
204  *		NLM4_DENIED_GRACE_PERIOD = 4,
205  *		NLM4_DEADLCK = 5,
206  *		NLM4_ROFS = 6,
207  *		NLM4_STALE_FH = 7,
208  *		NLM4_FBIG = 8,
209  *		NLM4_FAILED = 9
210  *	};
211  *
212  *	struct nlm4_stat {
213  *		nlm4_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 static void encode_nlm4_stat(struct xdr_stream *xdr,
221 			     const __be32 stat)
222 {
223 	__be32 *p;
224 
225 	BUG_ON(be32_to_cpu(stat) > NLM_FAILED);
226 	p = xdr_reserve_space(xdr, 4);
227 	*p = stat;
228 }
229 
230 static int decode_nlm4_stat(struct xdr_stream *xdr, __be32 *stat)
231 {
232 	__be32 *p;
233 
234 	p = xdr_inline_decode(xdr, 4);
235 	if (unlikely(p == NULL))
236 		goto out_overflow;
237 	if (unlikely(ntohl(*p) > ntohl(nlm4_failed)))
238 		goto out_bad_xdr;
239 	*stat = *p;
240 	return 0;
241 out_bad_xdr:
242 	dprintk("%s: server returned invalid nlm4_stats value: %u\n",
243 			__func__, be32_to_cpup(p));
244 	return -EIO;
245 out_overflow:
246 	print_overflow_msg(__func__, xdr);
247 	return -EIO;
248 }
249 
250 /*
251  *	struct nlm4_holder {
252  *		bool	exclusive;
253  *		int32	svid;
254  *		netobj	oh;
255  *		uint64	l_offset;
256  *		uint64	l_len;
257  *	};
258  */
259 static void encode_nlm4_holder(struct xdr_stream *xdr,
260 			       const struct nlm_res *result)
261 {
262 	const struct nlm_lock *lock = &result->lock;
263 	u64 l_offset, l_len;
264 	__be32 *p;
265 
266 	encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
267 	encode_int32(xdr, lock->svid);
268 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
269 
270 	p = xdr_reserve_space(xdr, 4 + 4);
271 	nlm4_compute_offsets(lock, &l_offset, &l_len);
272 	p = xdr_encode_hyper(p, l_offset);
273 	xdr_encode_hyper(p, l_len);
274 }
275 
276 static int decode_nlm4_holder(struct xdr_stream *xdr, struct nlm_res *result)
277 {
278 	struct nlm_lock *lock = &result->lock;
279 	struct file_lock *fl = &lock->fl;
280 	u64 l_offset, l_len;
281 	u32 exclusive;
282 	int error;
283 	__be32 *p;
284 	s32 end;
285 
286 	memset(lock, 0, sizeof(*lock));
287 	locks_init_lock(fl);
288 
289 	p = xdr_inline_decode(xdr, 4 + 4);
290 	if (unlikely(p == NULL))
291 		goto out_overflow;
292 	exclusive = be32_to_cpup(p++);
293 	lock->svid = be32_to_cpup(p);
294 	fl->fl_pid = (pid_t)lock->svid;
295 
296 	error = decode_netobj(xdr, &lock->oh);
297 	if (unlikely(error))
298 		goto out;
299 
300 	p = xdr_inline_decode(xdr, 8 + 8);
301 	if (unlikely(p == NULL))
302 		goto out_overflow;
303 
304 	fl->fl_flags = FL_POSIX;
305 	fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
306 	p = xdr_decode_hyper(p, &l_offset);
307 	xdr_decode_hyper(p, &l_len);
308 	end = l_offset + l_len - 1;
309 
310 	fl->fl_start = (loff_t)l_offset;
311 	if (l_len == 0 || end < 0)
312 		fl->fl_end = OFFSET_MAX;
313 	else
314 		fl->fl_end = (loff_t)end;
315 	error = 0;
316 out:
317 	return error;
318 out_overflow:
319 	print_overflow_msg(__func__, xdr);
320 	return -EIO;
321 }
322 
323 /*
324  *	string caller_name<LM_MAXSTRLEN>;
325  */
326 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
327 {
328 	/* NB: client-side does not set lock->len */
329 	u32 length = strlen(name);
330 	__be32 *p;
331 
332 	p = xdr_reserve_space(xdr, 4 + length);
333 	xdr_encode_opaque(p, name, length);
334 }
335 
336 /*
337  *	struct nlm4_lock {
338  *		string	caller_name<LM_MAXSTRLEN>;
339  *		netobj	fh;
340  *		netobj	oh;
341  *		int32	svid;
342  *		uint64	l_offset;
343  *		uint64	l_len;
344  *	};
345  */
346 static void encode_nlm4_lock(struct xdr_stream *xdr,
347 			     const struct nlm_lock *lock)
348 {
349 	u64 l_offset, l_len;
350 	__be32 *p;
351 
352 	encode_caller_name(xdr, lock->caller);
353 	encode_fh(xdr, &lock->fh);
354 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
355 
356 	p = xdr_reserve_space(xdr, 4 + 8 + 8);
357 	*p++ = cpu_to_be32(lock->svid);
358 
359 	nlm4_compute_offsets(lock, &l_offset, &l_len);
360 	p = xdr_encode_hyper(p, l_offset);
361 	xdr_encode_hyper(p, l_len);
362 }
363 
364 
365 /*
366  * NLMv4 XDR encode functions
367  *
368  * NLMv4 argument types are defined in Appendix II of RFC 1813:
369  * "NFS Version 3 Protocol Specification" and Chapter 10 of X/Open's
370  * "Protocols for Interworking: XNFS, Version 3W".
371  */
372 
373 /*
374  *	struct nlm4_testargs {
375  *		netobj cookie;
376  *		bool exclusive;
377  *		struct nlm4_lock alock;
378  *	};
379  */
380 static void nlm4_xdr_enc_testargs(struct rpc_rqst *req,
381 				  struct xdr_stream *xdr,
382 				  const struct nlm_args *args)
383 {
384 	const struct nlm_lock *lock = &args->lock;
385 
386 	encode_cookie(xdr, &args->cookie);
387 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
388 	encode_nlm4_lock(xdr, lock);
389 }
390 
391 /*
392  *	struct nlm4_lockargs {
393  *		netobj cookie;
394  *		bool block;
395  *		bool exclusive;
396  *		struct nlm4_lock alock;
397  *		bool reclaim;
398  *		int state;
399  *	};
400  */
401 static void nlm4_xdr_enc_lockargs(struct rpc_rqst *req,
402 				  struct xdr_stream *xdr,
403 				  const struct nlm_args *args)
404 {
405 	const struct nlm_lock *lock = &args->lock;
406 
407 	encode_cookie(xdr, &args->cookie);
408 	encode_bool(xdr, args->block);
409 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
410 	encode_nlm4_lock(xdr, lock);
411 	encode_bool(xdr, args->reclaim);
412 	encode_int32(xdr, args->state);
413 }
414 
415 /*
416  *	struct nlm4_cancargs {
417  *		netobj cookie;
418  *		bool block;
419  *		bool exclusive;
420  *		struct nlm4_lock alock;
421  *	};
422  */
423 static void nlm4_xdr_enc_cancargs(struct rpc_rqst *req,
424 				  struct xdr_stream *xdr,
425 				  const struct nlm_args *args)
426 {
427 	const struct nlm_lock *lock = &args->lock;
428 
429 	encode_cookie(xdr, &args->cookie);
430 	encode_bool(xdr, args->block);
431 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
432 	encode_nlm4_lock(xdr, lock);
433 }
434 
435 /*
436  *	struct nlm4_unlockargs {
437  *		netobj cookie;
438  *		struct nlm4_lock alock;
439  *	};
440  */
441 static void nlm4_xdr_enc_unlockargs(struct rpc_rqst *req,
442 				    struct xdr_stream *xdr,
443 				    const struct nlm_args *args)
444 {
445 	const struct nlm_lock *lock = &args->lock;
446 
447 	encode_cookie(xdr, &args->cookie);
448 	encode_nlm4_lock(xdr, lock);
449 }
450 
451 /*
452  *	struct nlm4_res {
453  *		netobj cookie;
454  *		nlm4_stat stat;
455  *	};
456  */
457 static void nlm4_xdr_enc_res(struct rpc_rqst *req,
458 			     struct xdr_stream *xdr,
459 			     const struct nlm_res *result)
460 {
461 	encode_cookie(xdr, &result->cookie);
462 	encode_nlm4_stat(xdr, result->status);
463 }
464 
465 /*
466  *	union nlm4_testrply switch (nlm4_stats stat) {
467  *	case NLM4_DENIED:
468  *		struct nlm4_holder holder;
469  *	default:
470  *		void;
471  *	};
472  *
473  *	struct nlm4_testres {
474  *		netobj cookie;
475  *		nlm4_testrply test_stat;
476  *	};
477  */
478 static void nlm4_xdr_enc_testres(struct rpc_rqst *req,
479 				 struct xdr_stream *xdr,
480 				 const struct nlm_res *result)
481 {
482 	encode_cookie(xdr, &result->cookie);
483 	encode_nlm4_stat(xdr, result->status);
484 	if (result->status == nlm_lck_denied)
485 		encode_nlm4_holder(xdr, result);
486 }
487 
488 
489 /*
490  * NLMv4 XDR decode functions
491  *
492  * NLMv4 argument types are defined in Appendix II of RFC 1813:
493  * "NFS Version 3 Protocol Specification" and Chapter 10 of X/Open's
494  * "Protocols for Interworking: XNFS, Version 3W".
495  */
496 
497 /*
498  *	union nlm4_testrply switch (nlm4_stats stat) {
499  *	case NLM4_DENIED:
500  *		struct nlm4_holder holder;
501  *	default:
502  *		void;
503  *	};
504  *
505  *	struct nlm4_testres {
506  *		netobj cookie;
507  *		nlm4_testrply test_stat;
508  *	};
509  */
510 static int decode_nlm4_testrply(struct xdr_stream *xdr,
511 				struct nlm_res *result)
512 {
513 	int error;
514 
515 	error = decode_nlm4_stat(xdr, &result->status);
516 	if (unlikely(error))
517 		goto out;
518 	if (result->status == nlm_lck_denied)
519 		error = decode_nlm4_holder(xdr, result);
520 out:
521 	return error;
522 }
523 
524 static int nlm4_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_nlm4_testrply(xdr, result);
534 out:
535 	return error;
536 }
537 
538 /*
539  *	struct nlm4_res {
540  *		netobj cookie;
541  *		nlm4_stat stat;
542  *	};
543  */
544 static int nlm4_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_nlm4_stat(xdr, &result->status);
554 out:
555 	return error;
556 }
557 
558 
559 /*
560  * For NLM, a void procedure really returns nothing
561  */
562 #define nlm4_xdr_dec_norep	NULL
563 
564 #define PROC(proc, argtype, restype)					\
565 [NLMPROC_##proc] = {							\
566 	.p_proc      = NLMPROC_##proc,					\
567 	.p_encode    = (kxdreproc_t)nlm4_xdr_enc_##argtype,		\
568 	.p_decode    = (kxdrdproc_t)nlm4_xdr_dec_##restype,		\
569 	.p_arglen    = NLM4_##argtype##_sz,				\
570 	.p_replen    = NLM4_##restype##_sz,				\
571 	.p_statidx   = NLMPROC_##proc,					\
572 	.p_name      = #proc,						\
573 	}
574 
575 static struct rpc_procinfo	nlm4_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 
593 const struct rpc_version nlm_version4 = {
594 	.number		= 4,
595 	.nrprocs	= ARRAY_SIZE(nlm4_procedures),
596 	.procs		= nlm4_procedures,
597 };
598