xref: /linux/include/linux/sunrpc/xdr.h (revision 2da68a77)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * XDR standard data types and function declarations
4  *
5  * Copyright (C) 1995-1997 Olaf Kirch <okir@monad.swb.de>
6  *
7  * Based on:
8  *   RFC 4506 "XDR: External Data Representation Standard", May 2006
9  */
10 
11 #ifndef _SUNRPC_XDR_H_
12 #define _SUNRPC_XDR_H_
13 
14 #include <linux/uio.h>
15 #include <asm/byteorder.h>
16 #include <asm/unaligned.h>
17 #include <linux/scatterlist.h>
18 
19 struct bio_vec;
20 struct rpc_rqst;
21 
22 /*
23  * Size of an XDR encoding unit in bytes, i.e. 32 bits,
24  * as defined in Section 3 of RFC 4506. All encoded
25  * XDR data items are aligned on a boundary of 32 bits.
26  */
27 #define XDR_UNIT		sizeof(__be32)
28 
29 /*
30  * Buffer adjustment
31  */
32 #define XDR_QUADLEN(l)		(((l) + 3) >> 2)
33 
34 /*
35  * Generic opaque `network object.'
36  */
37 #define XDR_MAX_NETOBJ		1024
38 struct xdr_netobj {
39 	unsigned int		len;
40 	u8 *			data;
41 };
42 
43 /*
44  * Basic structure for transmission/reception of a client XDR message.
45  * Features a header (for a linear buffer containing RPC headers
46  * and the data payload for short messages), and then an array of
47  * pages.
48  * The tail iovec allows you to append data after the page array. Its
49  * main interest is for appending padding to the pages in order to
50  * satisfy the int_32-alignment requirements in RFC1832.
51  *
52  * For the future, we might want to string several of these together
53  * in a list if anybody wants to make use of NFSv4 COMPOUND
54  * operations and/or has a need for scatter/gather involving pages.
55  */
56 struct xdr_buf {
57 	struct kvec	head[1],	/* RPC header + non-page data */
58 			tail[1];	/* Appended after page data */
59 
60 	struct bio_vec	*bvec;
61 	struct page **	pages;		/* Array of pages */
62 	unsigned int	page_base,	/* Start of page data */
63 			page_len,	/* Length of page data */
64 			flags;		/* Flags for data disposition */
65 #define XDRBUF_READ		0x01		/* target of file read */
66 #define XDRBUF_WRITE		0x02		/* source of file write */
67 #define XDRBUF_SPARSE_PAGES	0x04		/* Page array is sparse */
68 
69 	unsigned int	buflen,		/* Total length of storage buffer */
70 			len;		/* Length of XDR encoded message */
71 };
72 
73 static inline void
74 xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
75 {
76 	buf->head[0].iov_base = start;
77 	buf->head[0].iov_len = len;
78 	buf->tail[0].iov_len = 0;
79 	buf->pages = NULL;
80 	buf->page_len = 0;
81 	buf->flags = 0;
82 	buf->len = 0;
83 	buf->buflen = len;
84 }
85 
86 /*
87  * pre-xdr'ed macros.
88  */
89 
90 #define	xdr_zero	cpu_to_be32(0)
91 #define	xdr_one		cpu_to_be32(1)
92 #define	xdr_two		cpu_to_be32(2)
93 
94 #define	rpc_auth_null	cpu_to_be32(RPC_AUTH_NULL)
95 #define	rpc_auth_unix	cpu_to_be32(RPC_AUTH_UNIX)
96 #define	rpc_auth_short	cpu_to_be32(RPC_AUTH_SHORT)
97 #define	rpc_auth_gss	cpu_to_be32(RPC_AUTH_GSS)
98 #define	rpc_auth_tls	cpu_to_be32(RPC_AUTH_TLS)
99 
100 #define	rpc_call	cpu_to_be32(RPC_CALL)
101 #define	rpc_reply	cpu_to_be32(RPC_REPLY)
102 
103 #define	rpc_msg_accepted	cpu_to_be32(RPC_MSG_ACCEPTED)
104 
105 #define	rpc_success		cpu_to_be32(RPC_SUCCESS)
106 #define	rpc_prog_unavail	cpu_to_be32(RPC_PROG_UNAVAIL)
107 #define	rpc_prog_mismatch	cpu_to_be32(RPC_PROG_MISMATCH)
108 #define	rpc_proc_unavail	cpu_to_be32(RPC_PROC_UNAVAIL)
109 #define	rpc_garbage_args	cpu_to_be32(RPC_GARBAGE_ARGS)
110 #define	rpc_system_err		cpu_to_be32(RPC_SYSTEM_ERR)
111 #define	rpc_drop_reply		cpu_to_be32(RPC_DROP_REPLY)
112 
113 #define	rpc_mismatch		cpu_to_be32(RPC_MISMATCH)
114 #define	rpc_auth_error		cpu_to_be32(RPC_AUTH_ERROR)
115 
116 #define	rpc_auth_ok		cpu_to_be32(RPC_AUTH_OK)
117 #define	rpc_autherr_badcred	cpu_to_be32(RPC_AUTH_BADCRED)
118 #define	rpc_autherr_rejectedcred cpu_to_be32(RPC_AUTH_REJECTEDCRED)
119 #define	rpc_autherr_badverf	cpu_to_be32(RPC_AUTH_BADVERF)
120 #define	rpc_autherr_rejectedverf cpu_to_be32(RPC_AUTH_REJECTEDVERF)
121 #define	rpc_autherr_tooweak	cpu_to_be32(RPC_AUTH_TOOWEAK)
122 #define	rpcsec_gsserr_credproblem	cpu_to_be32(RPCSEC_GSS_CREDPROBLEM)
123 #define	rpcsec_gsserr_ctxproblem	cpu_to_be32(RPCSEC_GSS_CTXPROBLEM)
124 
125 /*
126  * Miscellaneous XDR helper functions
127  */
128 __be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int len);
129 __be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int len);
130 __be32 *xdr_encode_string(__be32 *p, const char *s);
131 __be32 *xdr_decode_string_inplace(__be32 *p, char **sp, unsigned int *lenp,
132 			unsigned int maxlen);
133 __be32 *xdr_encode_netobj(__be32 *p, const struct xdr_netobj *);
134 __be32 *xdr_decode_netobj(__be32 *p, struct xdr_netobj *);
135 
136 void	xdr_inline_pages(struct xdr_buf *, unsigned int,
137 			 struct page **, unsigned int, unsigned int);
138 void	xdr_terminate_string(const struct xdr_buf *, const u32);
139 size_t	xdr_buf_pagecount(const struct xdr_buf *buf);
140 int	xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp);
141 void	xdr_free_bvec(struct xdr_buf *buf);
142 
143 static inline __be32 *xdr_encode_array(__be32 *p, const void *s, unsigned int len)
144 {
145 	return xdr_encode_opaque(p, s, len);
146 }
147 
148 /*
149  * Decode 64bit quantities (NFSv3 support)
150  */
151 static inline __be32 *
152 xdr_encode_hyper(__be32 *p, __u64 val)
153 {
154 	put_unaligned_be64(val, p);
155 	return p + 2;
156 }
157 
158 static inline __be32 *
159 xdr_decode_hyper(__be32 *p, __u64 *valp)
160 {
161 	*valp = get_unaligned_be64(p);
162 	return p + 2;
163 }
164 
165 static inline __be32 *
166 xdr_decode_opaque_fixed(__be32 *p, void *ptr, unsigned int len)
167 {
168 	memcpy(ptr, p, len);
169 	return p + XDR_QUADLEN(len);
170 }
171 
172 static inline void xdr_netobj_dup(struct xdr_netobj *dst,
173 				  struct xdr_netobj *src, gfp_t gfp_mask)
174 {
175 	dst->data = kmemdup(src->data, src->len, gfp_mask);
176 	dst->len = src->len;
177 }
178 
179 /*
180  * Adjust kvec to reflect end of xdr'ed data (RPC client XDR)
181  */
182 static inline int
183 xdr_adjust_iovec(struct kvec *iov, __be32 *p)
184 {
185 	return iov->iov_len = ((u8 *) p - (u8 *) iov->iov_base);
186 }
187 
188 /*
189  * XDR buffer helper functions
190  */
191 extern void xdr_shift_buf(struct xdr_buf *, size_t);
192 extern void xdr_buf_from_iov(const struct kvec *, struct xdr_buf *);
193 extern int xdr_buf_subsegment(const struct xdr_buf *, struct xdr_buf *, unsigned int, unsigned int);
194 extern void xdr_buf_trim(struct xdr_buf *, unsigned int);
195 extern int read_bytes_from_xdr_buf(const struct xdr_buf *, unsigned int, void *, unsigned int);
196 extern int write_bytes_to_xdr_buf(const struct xdr_buf *, unsigned int, void *, unsigned int);
197 
198 extern int xdr_encode_word(const struct xdr_buf *, unsigned int, u32);
199 extern int xdr_decode_word(const struct xdr_buf *, unsigned int, u32 *);
200 
201 struct xdr_array2_desc;
202 typedef int (*xdr_xcode_elem_t)(struct xdr_array2_desc *desc, void *elem);
203 struct xdr_array2_desc {
204 	unsigned int elem_size;
205 	unsigned int array_len;
206 	unsigned int array_maxlen;
207 	xdr_xcode_elem_t xcode;
208 };
209 
210 extern int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
211 			     struct xdr_array2_desc *desc);
212 extern int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
213 			     struct xdr_array2_desc *desc);
214 extern void _copy_from_pages(char *p, struct page **pages, size_t pgbase,
215 			     size_t len);
216 
217 /*
218  * Provide some simple tools for XDR buffer overflow-checking etc.
219  */
220 struct xdr_stream {
221 	__be32 *p;		/* start of available buffer */
222 	struct xdr_buf *buf;	/* XDR buffer to read/write */
223 
224 	__be32 *end;		/* end of available buffer space */
225 	struct kvec *iov;	/* pointer to the current kvec */
226 	struct kvec scratch;	/* Scratch buffer */
227 	struct page **page_ptr;	/* pointer to the current page */
228 	unsigned int nwords;	/* Remaining decode buffer length */
229 
230 	struct rpc_rqst *rqst;	/* For debugging */
231 };
232 
233 /*
234  * These are the xdr_stream style generic XDR encode and decode functions.
235  */
236 typedef void	(*kxdreproc_t)(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
237 		const void *obj);
238 typedef int	(*kxdrdproc_t)(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
239 		void *obj);
240 
241 extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf,
242 			    __be32 *p, struct rpc_rqst *rqst);
243 extern void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
244 			   struct page **pages, struct rpc_rqst *rqst);
245 extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);
246 extern int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec,
247 		size_t nbytes);
248 extern void __xdr_commit_encode(struct xdr_stream *xdr);
249 extern void xdr_truncate_encode(struct xdr_stream *xdr, size_t len);
250 extern int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen);
251 extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages,
252 		unsigned int base, unsigned int len);
253 extern unsigned int xdr_stream_pos(const struct xdr_stream *xdr);
254 extern unsigned int xdr_page_pos(const struct xdr_stream *xdr);
255 extern void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf,
256 			    __be32 *p, struct rpc_rqst *rqst);
257 extern void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
258 		struct page **pages, unsigned int len);
259 extern __be32 *xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes);
260 extern unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len);
261 extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len);
262 extern int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data);
263 extern void xdr_set_pagelen(struct xdr_stream *, unsigned int len);
264 extern bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
265 				  unsigned int len);
266 extern unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset,
267 					       unsigned int target, unsigned int length);
268 extern unsigned int xdr_stream_zero(struct xdr_stream *xdr, unsigned int offset,
269 				    unsigned int length);
270 
271 /**
272  * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
273  * @xdr: pointer to xdr_stream struct
274  * @buf: pointer to an empty buffer
275  * @buflen: size of 'buf'
276  *
277  * The scratch buffer is used when decoding from an array of pages.
278  * If an xdr_inline_decode() call spans across page boundaries, then
279  * we copy the data into the scratch buffer in order to allow linear
280  * access.
281  */
282 static inline void
283 xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
284 {
285 	xdr->scratch.iov_base = buf;
286 	xdr->scratch.iov_len = buflen;
287 }
288 
289 /**
290  * xdr_set_scratch_page - Attach a scratch buffer for decoding data
291  * @xdr: pointer to xdr_stream struct
292  * @page: an anonymous page
293  *
294  * See xdr_set_scratch_buffer().
295  */
296 static inline void
297 xdr_set_scratch_page(struct xdr_stream *xdr, struct page *page)
298 {
299 	xdr_set_scratch_buffer(xdr, page_address(page), PAGE_SIZE);
300 }
301 
302 /**
303  * xdr_reset_scratch_buffer - Clear scratch buffer information
304  * @xdr: pointer to xdr_stream struct
305  *
306  * See xdr_set_scratch_buffer().
307  */
308 static inline void
309 xdr_reset_scratch_buffer(struct xdr_stream *xdr)
310 {
311 	xdr_set_scratch_buffer(xdr, NULL, 0);
312 }
313 
314 /**
315  * xdr_commit_encode - Ensure all data is written to xdr->buf
316  * @xdr: pointer to xdr_stream
317  *
318  * Handle encoding across page boundaries by giving the caller a
319  * temporary location to write to, then later copying the data into
320  * place. __xdr_commit_encode() does that copying.
321  */
322 static inline void xdr_commit_encode(struct xdr_stream *xdr)
323 {
324 	if (unlikely(xdr->scratch.iov_len))
325 		__xdr_commit_encode(xdr);
326 }
327 
328 /**
329  * xdr_stream_remaining - Return the number of bytes remaining in the stream
330  * @xdr: pointer to struct xdr_stream
331  *
332  * Return value:
333  *   Number of bytes remaining in @xdr before xdr->end
334  */
335 static inline size_t
336 xdr_stream_remaining(const struct xdr_stream *xdr)
337 {
338 	return xdr->nwords << 2;
339 }
340 
341 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr,
342 		size_t size);
343 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
344 		size_t maxlen, gfp_t gfp_flags);
345 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str,
346 		size_t size);
347 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
348 		size_t maxlen, gfp_t gfp_flags);
349 /**
350  * xdr_align_size - Calculate padded size of an object
351  * @n: Size of an object being XDR encoded (in bytes)
352  *
353  * Return value:
354  *   Size (in bytes) of the object including xdr padding
355  */
356 static inline size_t
357 xdr_align_size(size_t n)
358 {
359 	const size_t mask = XDR_UNIT - 1;
360 
361 	return (n + mask) & ~mask;
362 }
363 
364 /**
365  * xdr_pad_size - Calculate size of an object's pad
366  * @n: Size of an object being XDR encoded (in bytes)
367  *
368  * This implementation avoids the need for conditional
369  * branches or modulo division.
370  *
371  * Return value:
372  *   Size (in bytes) of the needed XDR pad
373  */
374 static inline size_t xdr_pad_size(size_t n)
375 {
376 	return xdr_align_size(n) - n;
377 }
378 
379 /**
380  * xdr_stream_encode_item_present - Encode a "present" list item
381  * @xdr: pointer to xdr_stream
382  *
383  * Return values:
384  *   On success, returns length in bytes of XDR buffer consumed
385  *   %-EMSGSIZE on XDR buffer overflow
386  */
387 static inline ssize_t xdr_stream_encode_item_present(struct xdr_stream *xdr)
388 {
389 	const size_t len = XDR_UNIT;
390 	__be32 *p = xdr_reserve_space(xdr, len);
391 
392 	if (unlikely(!p))
393 		return -EMSGSIZE;
394 	*p = xdr_one;
395 	return len;
396 }
397 
398 /**
399  * xdr_stream_encode_item_absent - Encode a "not present" list item
400  * @xdr: pointer to xdr_stream
401  *
402  * Return values:
403  *   On success, returns length in bytes of XDR buffer consumed
404  *   %-EMSGSIZE on XDR buffer overflow
405  */
406 static inline int xdr_stream_encode_item_absent(struct xdr_stream *xdr)
407 {
408 	const size_t len = XDR_UNIT;
409 	__be32 *p = xdr_reserve_space(xdr, len);
410 
411 	if (unlikely(!p))
412 		return -EMSGSIZE;
413 	*p = xdr_zero;
414 	return len;
415 }
416 
417 /**
418  * xdr_encode_bool - Encode a boolean item
419  * @p: address in a buffer into which to encode
420  * @n: boolean value to encode
421  *
422  * Return value:
423  *   Address of item following the encoded boolean
424  */
425 static inline __be32 *xdr_encode_bool(__be32 *p, u32 n)
426 {
427 	*p++ = n ? xdr_one : xdr_zero;
428 	return p;
429 }
430 
431 /**
432  * xdr_stream_encode_bool - Encode a boolean item
433  * @xdr: pointer to xdr_stream
434  * @n: boolean value to encode
435  *
436  * Return values:
437  *   On success, returns length in bytes of XDR buffer consumed
438  *   %-EMSGSIZE on XDR buffer overflow
439  */
440 static inline int xdr_stream_encode_bool(struct xdr_stream *xdr, __u32 n)
441 {
442 	const size_t len = XDR_UNIT;
443 	__be32 *p = xdr_reserve_space(xdr, len);
444 
445 	if (unlikely(!p))
446 		return -EMSGSIZE;
447 	xdr_encode_bool(p, n);
448 	return len;
449 }
450 
451 /**
452  * xdr_stream_encode_u32 - Encode a 32-bit integer
453  * @xdr: pointer to xdr_stream
454  * @n: integer to encode
455  *
456  * Return values:
457  *   On success, returns length in bytes of XDR buffer consumed
458  *   %-EMSGSIZE on XDR buffer overflow
459  */
460 static inline ssize_t
461 xdr_stream_encode_u32(struct xdr_stream *xdr, __u32 n)
462 {
463 	const size_t len = sizeof(n);
464 	__be32 *p = xdr_reserve_space(xdr, len);
465 
466 	if (unlikely(!p))
467 		return -EMSGSIZE;
468 	*p = cpu_to_be32(n);
469 	return len;
470 }
471 
472 /**
473  * xdr_stream_encode_u64 - Encode a 64-bit integer
474  * @xdr: pointer to xdr_stream
475  * @n: 64-bit integer to encode
476  *
477  * Return values:
478  *   On success, returns length in bytes of XDR buffer consumed
479  *   %-EMSGSIZE on XDR buffer overflow
480  */
481 static inline ssize_t
482 xdr_stream_encode_u64(struct xdr_stream *xdr, __u64 n)
483 {
484 	const size_t len = sizeof(n);
485 	__be32 *p = xdr_reserve_space(xdr, len);
486 
487 	if (unlikely(!p))
488 		return -EMSGSIZE;
489 	xdr_encode_hyper(p, n);
490 	return len;
491 }
492 
493 /**
494  * xdr_stream_encode_opaque_inline - Encode opaque xdr data
495  * @xdr: pointer to xdr_stream
496  * @ptr: pointer to void pointer
497  * @len: size of object
498  *
499  * Return values:
500  *   On success, returns length in bytes of XDR buffer consumed
501  *   %-EMSGSIZE on XDR buffer overflow
502  */
503 static inline ssize_t
504 xdr_stream_encode_opaque_inline(struct xdr_stream *xdr, void **ptr, size_t len)
505 {
506 	size_t count = sizeof(__u32) + xdr_align_size(len);
507 	__be32 *p = xdr_reserve_space(xdr, count);
508 
509 	if (unlikely(!p)) {
510 		*ptr = NULL;
511 		return -EMSGSIZE;
512 	}
513 	xdr_encode_opaque(p, NULL, len);
514 	*ptr = ++p;
515 	return count;
516 }
517 
518 /**
519  * xdr_stream_encode_opaque_fixed - Encode fixed length opaque xdr data
520  * @xdr: pointer to xdr_stream
521  * @ptr: pointer to opaque data object
522  * @len: size of object pointed to by @ptr
523  *
524  * Return values:
525  *   On success, returns length in bytes of XDR buffer consumed
526  *   %-EMSGSIZE on XDR buffer overflow
527  */
528 static inline ssize_t
529 xdr_stream_encode_opaque_fixed(struct xdr_stream *xdr, const void *ptr, size_t len)
530 {
531 	__be32 *p = xdr_reserve_space(xdr, len);
532 
533 	if (unlikely(!p))
534 		return -EMSGSIZE;
535 	xdr_encode_opaque_fixed(p, ptr, len);
536 	return xdr_align_size(len);
537 }
538 
539 /**
540  * xdr_stream_encode_opaque - Encode variable length opaque xdr data
541  * @xdr: pointer to xdr_stream
542  * @ptr: pointer to opaque data object
543  * @len: size of object pointed to by @ptr
544  *
545  * Return values:
546  *   On success, returns length in bytes of XDR buffer consumed
547  *   %-EMSGSIZE on XDR buffer overflow
548  */
549 static inline ssize_t
550 xdr_stream_encode_opaque(struct xdr_stream *xdr, const void *ptr, size_t len)
551 {
552 	size_t count = sizeof(__u32) + xdr_align_size(len);
553 	__be32 *p = xdr_reserve_space(xdr, count);
554 
555 	if (unlikely(!p))
556 		return -EMSGSIZE;
557 	xdr_encode_opaque(p, ptr, len);
558 	return count;
559 }
560 
561 /**
562  * xdr_stream_encode_uint32_array - Encode variable length array of integers
563  * @xdr: pointer to xdr_stream
564  * @array: array of integers
565  * @array_size: number of elements in @array
566  *
567  * Return values:
568  *   On success, returns length in bytes of XDR buffer consumed
569  *   %-EMSGSIZE on XDR buffer overflow
570  */
571 static inline ssize_t
572 xdr_stream_encode_uint32_array(struct xdr_stream *xdr,
573 		const __u32 *array, size_t array_size)
574 {
575 	ssize_t ret = (array_size+1) * sizeof(__u32);
576 	__be32 *p = xdr_reserve_space(xdr, ret);
577 
578 	if (unlikely(!p))
579 		return -EMSGSIZE;
580 	*p++ = cpu_to_be32(array_size);
581 	for (; array_size > 0; p++, array++, array_size--)
582 		*p = cpu_to_be32p(array);
583 	return ret;
584 }
585 
586 /**
587  * xdr_item_is_absent - symbolically handle XDR discriminators
588  * @p: pointer to undecoded discriminator
589  *
590  * Return values:
591  *   %true if the following XDR item is absent
592  *   %false if the following XDR item is present
593  */
594 static inline bool xdr_item_is_absent(const __be32 *p)
595 {
596 	return *p == xdr_zero;
597 }
598 
599 /**
600  * xdr_item_is_present - symbolically handle XDR discriminators
601  * @p: pointer to undecoded discriminator
602  *
603  * Return values:
604  *   %true if the following XDR item is present
605  *   %false if the following XDR item is absent
606  */
607 static inline bool xdr_item_is_present(const __be32 *p)
608 {
609 	return *p != xdr_zero;
610 }
611 
612 /**
613  * xdr_stream_decode_bool - Decode a boolean
614  * @xdr: pointer to xdr_stream
615  * @ptr: pointer to a u32 in which to store the result
616  *
617  * Return values:
618  *   %0 on success
619  *   %-EBADMSG on XDR buffer overflow
620  */
621 static inline ssize_t
622 xdr_stream_decode_bool(struct xdr_stream *xdr, __u32 *ptr)
623 {
624 	const size_t count = sizeof(*ptr);
625 	__be32 *p = xdr_inline_decode(xdr, count);
626 
627 	if (unlikely(!p))
628 		return -EBADMSG;
629 	*ptr = (*p != xdr_zero);
630 	return 0;
631 }
632 
633 /**
634  * xdr_stream_decode_u32 - Decode a 32-bit integer
635  * @xdr: pointer to xdr_stream
636  * @ptr: location to store integer
637  *
638  * Return values:
639  *   %0 on success
640  *   %-EBADMSG on XDR buffer overflow
641  */
642 static inline ssize_t
643 xdr_stream_decode_u32(struct xdr_stream *xdr, __u32 *ptr)
644 {
645 	const size_t count = sizeof(*ptr);
646 	__be32 *p = xdr_inline_decode(xdr, count);
647 
648 	if (unlikely(!p))
649 		return -EBADMSG;
650 	*ptr = be32_to_cpup(p);
651 	return 0;
652 }
653 
654 /**
655  * xdr_stream_decode_u64 - Decode a 64-bit integer
656  * @xdr: pointer to xdr_stream
657  * @ptr: location to store 64-bit integer
658  *
659  * Return values:
660  *   %0 on success
661  *   %-EBADMSG on XDR buffer overflow
662  */
663 static inline ssize_t
664 xdr_stream_decode_u64(struct xdr_stream *xdr, __u64 *ptr)
665 {
666 	const size_t count = sizeof(*ptr);
667 	__be32 *p = xdr_inline_decode(xdr, count);
668 
669 	if (unlikely(!p))
670 		return -EBADMSG;
671 	xdr_decode_hyper(p, ptr);
672 	return 0;
673 }
674 
675 /**
676  * xdr_stream_decode_opaque_fixed - Decode fixed length opaque xdr data
677  * @xdr: pointer to xdr_stream
678  * @ptr: location to store data
679  * @len: size of buffer pointed to by @ptr
680  *
681  * Return values:
682  *   On success, returns size of object stored in @ptr
683  *   %-EBADMSG on XDR buffer overflow
684  */
685 static inline ssize_t
686 xdr_stream_decode_opaque_fixed(struct xdr_stream *xdr, void *ptr, size_t len)
687 {
688 	__be32 *p = xdr_inline_decode(xdr, len);
689 
690 	if (unlikely(!p))
691 		return -EBADMSG;
692 	xdr_decode_opaque_fixed(p, ptr, len);
693 	return len;
694 }
695 
696 /**
697  * xdr_stream_decode_opaque_inline - Decode variable length opaque xdr data
698  * @xdr: pointer to xdr_stream
699  * @ptr: location to store pointer to opaque data
700  * @maxlen: maximum acceptable object size
701  *
702  * Note: the pointer stored in @ptr cannot be assumed valid after the XDR
703  * buffer has been destroyed, or even after calling xdr_inline_decode()
704  * on @xdr. It is therefore expected that the object it points to should
705  * be processed immediately.
706  *
707  * Return values:
708  *   On success, returns size of object stored in *@ptr
709  *   %-EBADMSG on XDR buffer overflow
710  *   %-EMSGSIZE if the size of the object would exceed @maxlen
711  */
712 static inline ssize_t
713 xdr_stream_decode_opaque_inline(struct xdr_stream *xdr, void **ptr, size_t maxlen)
714 {
715 	__be32 *p;
716 	__u32 len;
717 
718 	*ptr = NULL;
719 	if (unlikely(xdr_stream_decode_u32(xdr, &len) < 0))
720 		return -EBADMSG;
721 	if (len != 0) {
722 		p = xdr_inline_decode(xdr, len);
723 		if (unlikely(!p))
724 			return -EBADMSG;
725 		if (unlikely(len > maxlen))
726 			return -EMSGSIZE;
727 		*ptr = p;
728 	}
729 	return len;
730 }
731 
732 /**
733  * xdr_stream_decode_uint32_array - Decode variable length array of integers
734  * @xdr: pointer to xdr_stream
735  * @array: location to store the integer array or NULL
736  * @array_size: number of elements to store
737  *
738  * Return values:
739  *   On success, returns number of elements stored in @array
740  *   %-EBADMSG on XDR buffer overflow
741  *   %-EMSGSIZE if the size of the array exceeds @array_size
742  */
743 static inline ssize_t
744 xdr_stream_decode_uint32_array(struct xdr_stream *xdr,
745 		__u32 *array, size_t array_size)
746 {
747 	__be32 *p;
748 	__u32 len;
749 	ssize_t retval;
750 
751 	if (unlikely(xdr_stream_decode_u32(xdr, &len) < 0))
752 		return -EBADMSG;
753 	if (len > SIZE_MAX / sizeof(*p))
754 		return -EBADMSG;
755 	p = xdr_inline_decode(xdr, len * sizeof(*p));
756 	if (unlikely(!p))
757 		return -EBADMSG;
758 	if (array == NULL)
759 		return len;
760 	if (len <= array_size) {
761 		if (len < array_size)
762 			memset(array+len, 0, (array_size-len)*sizeof(*array));
763 		array_size = len;
764 		retval = len;
765 	} else
766 		retval = -EMSGSIZE;
767 	for (; array_size > 0; p++, array++, array_size--)
768 		*array = be32_to_cpup(p);
769 	return retval;
770 }
771 
772 #endif /* _SUNRPC_XDR_H_ */
773