Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/net/sunrpc/xdr.c | |
3 | * | |
4 | * Generic XDR support. | |
5 | * | |
6 | * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> | |
7 | */ | |
8 | ||
9 | #include <linux/types.h> | |
10 | #include <linux/socket.h> | |
11 | #include <linux/string.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/errno.h> | |
15 | #include <linux/in.h> | |
16 | #include <linux/net.h> | |
17 | #include <net/sock.h> | |
18 | #include <linux/sunrpc/xdr.h> | |
19 | #include <linux/sunrpc/msg_prot.h> | |
20 | ||
21 | /* | |
22 | * XDR functions for basic NFS types | |
23 | */ | |
24 | u32 * | |
25 | xdr_encode_netobj(u32 *p, const struct xdr_netobj *obj) | |
26 | { | |
27 | unsigned int quadlen = XDR_QUADLEN(obj->len); | |
28 | ||
29 | p[quadlen] = 0; /* zero trailing bytes */ | |
30 | *p++ = htonl(obj->len); | |
31 | memcpy(p, obj->data, obj->len); | |
32 | return p + XDR_QUADLEN(obj->len); | |
33 | } | |
34 | ||
35 | u32 * | |
36 | xdr_decode_netobj(u32 *p, struct xdr_netobj *obj) | |
37 | { | |
38 | unsigned int len; | |
39 | ||
40 | if ((len = ntohl(*p++)) > XDR_MAX_NETOBJ) | |
41 | return NULL; | |
42 | obj->len = len; | |
43 | obj->data = (u8 *) p; | |
44 | return p + XDR_QUADLEN(len); | |
45 | } | |
46 | ||
47 | /** | |
48 | * xdr_encode_opaque_fixed - Encode fixed length opaque data | |
49 | * @p - pointer to current position in XDR buffer. | |
50 | * @ptr - pointer to data to encode (or NULL) | |
51 | * @nbytes - size of data. | |
52 | * | |
53 | * Copy the array of data of length nbytes at ptr to the XDR buffer | |
54 | * at position p, then align to the next 32-bit boundary by padding | |
55 | * with zero bytes (see RFC1832). | |
56 | * Note: if ptr is NULL, only the padding is performed. | |
57 | * | |
58 | * Returns the updated current XDR buffer position | |
59 | * | |
60 | */ | |
61 | u32 *xdr_encode_opaque_fixed(u32 *p, const void *ptr, unsigned int nbytes) | |
62 | { | |
63 | if (likely(nbytes != 0)) { | |
64 | unsigned int quadlen = XDR_QUADLEN(nbytes); | |
65 | unsigned int padding = (quadlen << 2) - nbytes; | |
66 | ||
67 | if (ptr != NULL) | |
68 | memcpy(p, ptr, nbytes); | |
69 | if (padding != 0) | |
70 | memset((char *)p + nbytes, 0, padding); | |
71 | p += quadlen; | |
72 | } | |
73 | return p; | |
74 | } | |
75 | EXPORT_SYMBOL(xdr_encode_opaque_fixed); | |
76 | ||
77 | /** | |
78 | * xdr_encode_opaque - Encode variable length opaque data | |
79 | * @p - pointer to current position in XDR buffer. | |
80 | * @ptr - pointer to data to encode (or NULL) | |
81 | * @nbytes - size of data. | |
82 | * | |
83 | * Returns the updated current XDR buffer position | |
84 | */ | |
85 | u32 *xdr_encode_opaque(u32 *p, const void *ptr, unsigned int nbytes) | |
86 | { | |
87 | *p++ = htonl(nbytes); | |
88 | return xdr_encode_opaque_fixed(p, ptr, nbytes); | |
89 | } | |
90 | EXPORT_SYMBOL(xdr_encode_opaque); | |
91 | ||
92 | u32 * | |
93 | xdr_encode_string(u32 *p, const char *string) | |
94 | { | |
95 | return xdr_encode_array(p, string, strlen(string)); | |
96 | } | |
97 | ||
98 | u32 * | |
99 | xdr_decode_string(u32 *p, char **sp, int *lenp, int maxlen) | |
100 | { | |
101 | unsigned int len; | |
102 | char *string; | |
103 | ||
104 | if ((len = ntohl(*p++)) > maxlen) | |
105 | return NULL; | |
106 | if (lenp) | |
107 | *lenp = len; | |
108 | if ((len % 4) != 0) { | |
109 | string = (char *) p; | |
110 | } else { | |
111 | string = (char *) (p - 1); | |
112 | memmove(string, p, len); | |
113 | } | |
114 | string[len] = '\0'; | |
115 | *sp = string; | |
116 | return p + XDR_QUADLEN(len); | |
117 | } | |
118 | ||
119 | u32 * | |
120 | xdr_decode_string_inplace(u32 *p, char **sp, int *lenp, int maxlen) | |
121 | { | |
122 | unsigned int len; | |
123 | ||
124 | if ((len = ntohl(*p++)) > maxlen) | |
125 | return NULL; | |
126 | *lenp = len; | |
127 | *sp = (char *) p; | |
128 | return p + XDR_QUADLEN(len); | |
129 | } | |
130 | ||
131 | void | |
132 | xdr_encode_pages(struct xdr_buf *xdr, struct page **pages, unsigned int base, | |
133 | unsigned int len) | |
134 | { | |
135 | struct kvec *tail = xdr->tail; | |
136 | u32 *p; | |
137 | ||
138 | xdr->pages = pages; | |
139 | xdr->page_base = base; | |
140 | xdr->page_len = len; | |
141 | ||
142 | p = (u32 *)xdr->head[0].iov_base + XDR_QUADLEN(xdr->head[0].iov_len); | |
143 | tail->iov_base = p; | |
144 | tail->iov_len = 0; | |
145 | ||
146 | if (len & 3) { | |
147 | unsigned int pad = 4 - (len & 3); | |
148 | ||
149 | *p = 0; | |
150 | tail->iov_base = (char *)p + (len & 3); | |
151 | tail->iov_len = pad; | |
152 | len += pad; | |
153 | } | |
154 | xdr->buflen += len; | |
155 | xdr->len += len; | |
156 | } | |
157 | ||
158 | void | |
159 | xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset, | |
160 | struct page **pages, unsigned int base, unsigned int len) | |
161 | { | |
162 | struct kvec *head = xdr->head; | |
163 | struct kvec *tail = xdr->tail; | |
164 | char *buf = (char *)head->iov_base; | |
165 | unsigned int buflen = head->iov_len; | |
166 | ||
167 | head->iov_len = offset; | |
168 | ||
169 | xdr->pages = pages; | |
170 | xdr->page_base = base; | |
171 | xdr->page_len = len; | |
172 | ||
173 | tail->iov_base = buf + offset; | |
174 | tail->iov_len = buflen - offset; | |
175 | ||
176 | xdr->buflen += len; | |
177 | } | |
178 | ||
179 | void | |
180 | xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, | |
181 | skb_reader_t *desc, | |
182 | skb_read_actor_t copy_actor) | |
183 | { | |
184 | struct page **ppage = xdr->pages; | |
185 | unsigned int len, pglen = xdr->page_len; | |
186 | int ret; | |
187 | ||
188 | len = xdr->head[0].iov_len; | |
189 | if (base < len) { | |
190 | len -= base; | |
191 | ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len); | |
192 | if (ret != len || !desc->count) | |
193 | return; | |
194 | base = 0; | |
195 | } else | |
196 | base -= len; | |
197 | ||
198 | if (pglen == 0) | |
199 | goto copy_tail; | |
200 | if (base >= pglen) { | |
201 | base -= pglen; | |
202 | goto copy_tail; | |
203 | } | |
204 | if (base || xdr->page_base) { | |
205 | pglen -= base; | |
206 | base += xdr->page_base; | |
207 | ppage += base >> PAGE_CACHE_SHIFT; | |
208 | base &= ~PAGE_CACHE_MASK; | |
209 | } | |
210 | do { | |
211 | char *kaddr; | |
212 | ||
213 | len = PAGE_CACHE_SIZE; | |
214 | kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA); | |
215 | if (base) { | |
216 | len -= base; | |
217 | if (pglen < len) | |
218 | len = pglen; | |
219 | ret = copy_actor(desc, kaddr + base, len); | |
220 | base = 0; | |
221 | } else { | |
222 | if (pglen < len) | |
223 | len = pglen; | |
224 | ret = copy_actor(desc, kaddr, len); | |
225 | } | |
226 | flush_dcache_page(*ppage); | |
227 | kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA); | |
228 | if (ret != len || !desc->count) | |
229 | return; | |
230 | ppage++; | |
231 | } while ((pglen -= len) != 0); | |
232 | copy_tail: | |
233 | len = xdr->tail[0].iov_len; | |
234 | if (base < len) | |
235 | copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base); | |
236 | } | |
237 | ||
238 | ||
239 | int | |
240 | xdr_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, | |
241 | struct xdr_buf *xdr, unsigned int base, int msgflags) | |
242 | { | |
243 | struct page **ppage = xdr->pages; | |
244 | unsigned int len, pglen = xdr->page_len; | |
245 | int err, ret = 0; | |
246 | ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int); | |
247 | ||
248 | len = xdr->head[0].iov_len; | |
249 | if (base < len || (addr != NULL && base == 0)) { | |
250 | struct kvec iov = { | |
251 | .iov_base = xdr->head[0].iov_base + base, | |
252 | .iov_len = len - base, | |
253 | }; | |
254 | struct msghdr msg = { | |
255 | .msg_name = addr, | |
256 | .msg_namelen = addrlen, | |
257 | .msg_flags = msgflags, | |
258 | }; | |
259 | if (xdr->len > len) | |
260 | msg.msg_flags |= MSG_MORE; | |
261 | ||
262 | if (iov.iov_len != 0) | |
263 | err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len); | |
264 | else | |
265 | err = kernel_sendmsg(sock, &msg, NULL, 0, 0); | |
266 | if (ret == 0) | |
267 | ret = err; | |
268 | else if (err > 0) | |
269 | ret += err; | |
270 | if (err != iov.iov_len) | |
271 | goto out; | |
272 | base = 0; | |
273 | } else | |
274 | base -= len; | |
275 | ||
276 | if (pglen == 0) | |
277 | goto copy_tail; | |
278 | if (base >= pglen) { | |
279 | base -= pglen; | |
280 | goto copy_tail; | |
281 | } | |
282 | if (base || xdr->page_base) { | |
283 | pglen -= base; | |
284 | base += xdr->page_base; | |
285 | ppage += base >> PAGE_CACHE_SHIFT; | |
286 | base &= ~PAGE_CACHE_MASK; | |
287 | } | |
288 | ||
289 | sendpage = sock->ops->sendpage ? : sock_no_sendpage; | |
290 | do { | |
291 | int flags = msgflags; | |
292 | ||
293 | len = PAGE_CACHE_SIZE; | |
294 | if (base) | |
295 | len -= base; | |
296 | if (pglen < len) | |
297 | len = pglen; | |
298 | ||
299 | if (pglen != len || xdr->tail[0].iov_len != 0) | |
300 | flags |= MSG_MORE; | |
301 | ||
302 | /* Hmm... We might be dealing with highmem pages */ | |
303 | if (PageHighMem(*ppage)) | |
304 | sendpage = sock_no_sendpage; | |
305 | err = sendpage(sock, *ppage, base, len, flags); | |
306 | if (ret == 0) | |
307 | ret = err; | |
308 | else if (err > 0) | |
309 | ret += err; | |
310 | if (err != len) | |
311 | goto out; | |
312 | base = 0; | |
313 | ppage++; | |
314 | } while ((pglen -= len) != 0); | |
315 | copy_tail: | |
316 | len = xdr->tail[0].iov_len; | |
317 | if (base < len) { | |
318 | struct kvec iov = { | |
319 | .iov_base = xdr->tail[0].iov_base + base, | |
320 | .iov_len = len - base, | |
321 | }; | |
322 | struct msghdr msg = { | |
323 | .msg_flags = msgflags, | |
324 | }; | |
325 | err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len); | |
326 | if (ret == 0) | |
327 | ret = err; | |
328 | else if (err > 0) | |
329 | ret += err; | |
330 | } | |
331 | out: | |
332 | return ret; | |
333 | } | |
334 | ||
335 | ||
336 | /* | |
337 | * Helper routines for doing 'memmove' like operations on a struct xdr_buf | |
338 | * | |
339 | * _shift_data_right_pages | |
340 | * @pages: vector of pages containing both the source and dest memory area. | |
341 | * @pgto_base: page vector address of destination | |
342 | * @pgfrom_base: page vector address of source | |
343 | * @len: number of bytes to copy | |
344 | * | |
345 | * Note: the addresses pgto_base and pgfrom_base are both calculated in | |
346 | * the same way: | |
347 | * if a memory area starts at byte 'base' in page 'pages[i]', | |
348 | * then its address is given as (i << PAGE_CACHE_SHIFT) + base | |
349 | * Also note: pgfrom_base must be < pgto_base, but the memory areas | |
350 | * they point to may overlap. | |
351 | */ | |
352 | static void | |
353 | _shift_data_right_pages(struct page **pages, size_t pgto_base, | |
354 | size_t pgfrom_base, size_t len) | |
355 | { | |
356 | struct page **pgfrom, **pgto; | |
357 | char *vfrom, *vto; | |
358 | size_t copy; | |
359 | ||
360 | BUG_ON(pgto_base <= pgfrom_base); | |
361 | ||
362 | pgto_base += len; | |
363 | pgfrom_base += len; | |
364 | ||
365 | pgto = pages + (pgto_base >> PAGE_CACHE_SHIFT); | |
366 | pgfrom = pages + (pgfrom_base >> PAGE_CACHE_SHIFT); | |
367 | ||
368 | pgto_base &= ~PAGE_CACHE_MASK; | |
369 | pgfrom_base &= ~PAGE_CACHE_MASK; | |
370 | ||
371 | do { | |
372 | /* Are any pointers crossing a page boundary? */ | |
373 | if (pgto_base == 0) { | |
374 | flush_dcache_page(*pgto); | |
375 | pgto_base = PAGE_CACHE_SIZE; | |
376 | pgto--; | |
377 | } | |
378 | if (pgfrom_base == 0) { | |
379 | pgfrom_base = PAGE_CACHE_SIZE; | |
380 | pgfrom--; | |
381 | } | |
382 | ||
383 | copy = len; | |
384 | if (copy > pgto_base) | |
385 | copy = pgto_base; | |
386 | if (copy > pgfrom_base) | |
387 | copy = pgfrom_base; | |
388 | pgto_base -= copy; | |
389 | pgfrom_base -= copy; | |
390 | ||
391 | vto = kmap_atomic(*pgto, KM_USER0); | |
392 | vfrom = kmap_atomic(*pgfrom, KM_USER1); | |
393 | memmove(vto + pgto_base, vfrom + pgfrom_base, copy); | |
394 | kunmap_atomic(vfrom, KM_USER1); | |
395 | kunmap_atomic(vto, KM_USER0); | |
396 | ||
397 | } while ((len -= copy) != 0); | |
398 | flush_dcache_page(*pgto); | |
399 | } | |
400 | ||
401 | /* | |
402 | * _copy_to_pages | |
403 | * @pages: array of pages | |
404 | * @pgbase: page vector address of destination | |
405 | * @p: pointer to source data | |
406 | * @len: length | |
407 | * | |
408 | * Copies data from an arbitrary memory location into an array of pages | |
409 | * The copy is assumed to be non-overlapping. | |
410 | */ | |
411 | static void | |
412 | _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len) | |
413 | { | |
414 | struct page **pgto; | |
415 | char *vto; | |
416 | size_t copy; | |
417 | ||
418 | pgto = pages + (pgbase >> PAGE_CACHE_SHIFT); | |
419 | pgbase &= ~PAGE_CACHE_MASK; | |
420 | ||
421 | do { | |
422 | copy = PAGE_CACHE_SIZE - pgbase; | |
423 | if (copy > len) | |
424 | copy = len; | |
425 | ||
426 | vto = kmap_atomic(*pgto, KM_USER0); | |
427 | memcpy(vto + pgbase, p, copy); | |
428 | kunmap_atomic(vto, KM_USER0); | |
429 | ||
430 | pgbase += copy; | |
431 | if (pgbase == PAGE_CACHE_SIZE) { | |
432 | flush_dcache_page(*pgto); | |
433 | pgbase = 0; | |
434 | pgto++; | |
435 | } | |
436 | p += copy; | |
437 | ||
438 | } while ((len -= copy) != 0); | |
439 | flush_dcache_page(*pgto); | |
440 | } | |
441 | ||
442 | /* | |
443 | * _copy_from_pages | |
444 | * @p: pointer to destination | |
445 | * @pages: array of pages | |
446 | * @pgbase: offset of source data | |
447 | * @len: length | |
448 | * | |
449 | * Copies data into an arbitrary memory location from an array of pages | |
450 | * The copy is assumed to be non-overlapping. | |
451 | */ | |
452 | static void | |
453 | _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len) | |
454 | { | |
455 | struct page **pgfrom; | |
456 | char *vfrom; | |
457 | size_t copy; | |
458 | ||
459 | pgfrom = pages + (pgbase >> PAGE_CACHE_SHIFT); | |
460 | pgbase &= ~PAGE_CACHE_MASK; | |
461 | ||
462 | do { | |
463 | copy = PAGE_CACHE_SIZE - pgbase; | |
464 | if (copy > len) | |
465 | copy = len; | |
466 | ||
467 | vfrom = kmap_atomic(*pgfrom, KM_USER0); | |
468 | memcpy(p, vfrom + pgbase, copy); | |
469 | kunmap_atomic(vfrom, KM_USER0); | |
470 | ||
471 | pgbase += copy; | |
472 | if (pgbase == PAGE_CACHE_SIZE) { | |
473 | pgbase = 0; | |
474 | pgfrom++; | |
475 | } | |
476 | p += copy; | |
477 | ||
478 | } while ((len -= copy) != 0); | |
479 | } | |
480 | ||
481 | /* | |
482 | * xdr_shrink_bufhead | |
483 | * @buf: xdr_buf | |
484 | * @len: bytes to remove from buf->head[0] | |
485 | * | |
486 | * Shrinks XDR buffer's header kvec buf->head[0] by | |
487 | * 'len' bytes. The extra data is not lost, but is instead | |
488 | * moved into the inlined pages and/or the tail. | |
489 | */ | |
490 | static void | |
491 | xdr_shrink_bufhead(struct xdr_buf *buf, size_t len) | |
492 | { | |
493 | struct kvec *head, *tail; | |
494 | size_t copy, offs; | |
495 | unsigned int pglen = buf->page_len; | |
496 | ||
497 | tail = buf->tail; | |
498 | head = buf->head; | |
499 | BUG_ON (len > head->iov_len); | |
500 | ||
501 | /* Shift the tail first */ | |
502 | if (tail->iov_len != 0) { | |
503 | if (tail->iov_len > len) { | |
504 | copy = tail->iov_len - len; | |
505 | memmove((char *)tail->iov_base + len, | |
506 | tail->iov_base, copy); | |
507 | } | |
508 | /* Copy from the inlined pages into the tail */ | |
509 | copy = len; | |
510 | if (copy > pglen) | |
511 | copy = pglen; | |
512 | offs = len - copy; | |
513 | if (offs >= tail->iov_len) | |
514 | copy = 0; | |
515 | else if (copy > tail->iov_len - offs) | |
516 | copy = tail->iov_len - offs; | |
517 | if (copy != 0) | |
518 | _copy_from_pages((char *)tail->iov_base + offs, | |
519 | buf->pages, | |
520 | buf->page_base + pglen + offs - len, | |
521 | copy); | |
522 | /* Do we also need to copy data from the head into the tail ? */ | |
523 | if (len > pglen) { | |
524 | offs = copy = len - pglen; | |
525 | if (copy > tail->iov_len) | |
526 | copy = tail->iov_len; | |
527 | memcpy(tail->iov_base, | |
528 | (char *)head->iov_base + | |
529 | head->iov_len - offs, | |
530 | copy); | |
531 | } | |
532 | } | |
533 | /* Now handle pages */ | |
534 | if (pglen != 0) { | |
535 | if (pglen > len) | |
536 | _shift_data_right_pages(buf->pages, | |
537 | buf->page_base + len, | |
538 | buf->page_base, | |
539 | pglen - len); | |
540 | copy = len; | |
541 | if (len > pglen) | |
542 | copy = pglen; | |
543 | _copy_to_pages(buf->pages, buf->page_base, | |
544 | (char *)head->iov_base + head->iov_len - len, | |
545 | copy); | |
546 | } | |
547 | head->iov_len -= len; | |
548 | buf->buflen -= len; | |
549 | /* Have we truncated the message? */ | |
550 | if (buf->len > buf->buflen) | |
551 | buf->len = buf->buflen; | |
552 | } | |
553 | ||
554 | /* | |
555 | * xdr_shrink_pagelen | |
556 | * @buf: xdr_buf | |
557 | * @len: bytes to remove from buf->pages | |
558 | * | |
559 | * Shrinks XDR buffer's page array buf->pages by | |
560 | * 'len' bytes. The extra data is not lost, but is instead | |
561 | * moved into the tail. | |
562 | */ | |
563 | static void | |
564 | xdr_shrink_pagelen(struct xdr_buf *buf, size_t len) | |
565 | { | |
566 | struct kvec *tail; | |
567 | size_t copy; | |
568 | char *p; | |
569 | unsigned int pglen = buf->page_len; | |
570 | ||
571 | tail = buf->tail; | |
572 | BUG_ON (len > pglen); | |
573 | ||
574 | /* Shift the tail first */ | |
575 | if (tail->iov_len != 0) { | |
576 | p = (char *)tail->iov_base + len; | |
577 | if (tail->iov_len > len) { | |
578 | copy = tail->iov_len - len; | |
579 | memmove(p, tail->iov_base, copy); | |
580 | } else | |
581 | buf->buflen -= len; | |
582 | /* Copy from the inlined pages into the tail */ | |
583 | copy = len; | |
584 | if (copy > tail->iov_len) | |
585 | copy = tail->iov_len; | |
586 | _copy_from_pages((char *)tail->iov_base, | |
587 | buf->pages, buf->page_base + pglen - len, | |
588 | copy); | |
589 | } | |
590 | buf->page_len -= len; | |
591 | buf->buflen -= len; | |
592 | /* Have we truncated the message? */ | |
593 | if (buf->len > buf->buflen) | |
594 | buf->len = buf->buflen; | |
595 | } | |
596 | ||
597 | void | |
598 | xdr_shift_buf(struct xdr_buf *buf, size_t len) | |
599 | { | |
600 | xdr_shrink_bufhead(buf, len); | |
601 | } | |
602 | ||
603 | /** | |
604 | * xdr_init_encode - Initialize a struct xdr_stream for sending data. | |
605 | * @xdr: pointer to xdr_stream struct | |
606 | * @buf: pointer to XDR buffer in which to encode data | |
607 | * @p: current pointer inside XDR buffer | |
608 | * | |
609 | * Note: at the moment the RPC client only passes the length of our | |
610 | * scratch buffer in the xdr_buf's header kvec. Previously this | |
611 | * meant we needed to call xdr_adjust_iovec() after encoding the | |
612 | * data. With the new scheme, the xdr_stream manages the details | |
613 | * of the buffer length, and takes care of adjusting the kvec | |
614 | * length for us. | |
615 | */ | |
616 | void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, uint32_t *p) | |
617 | { | |
618 | struct kvec *iov = buf->head; | |
619 | ||
620 | xdr->buf = buf; | |
621 | xdr->iov = iov; | |
622 | xdr->end = (uint32_t *)((char *)iov->iov_base + iov->iov_len); | |
623 | buf->len = iov->iov_len = (char *)p - (char *)iov->iov_base; | |
624 | xdr->p = p; | |
625 | } | |
626 | EXPORT_SYMBOL(xdr_init_encode); | |
627 | ||
628 | /** | |
629 | * xdr_reserve_space - Reserve buffer space for sending | |
630 | * @xdr: pointer to xdr_stream | |
631 | * @nbytes: number of bytes to reserve | |
632 | * | |
633 | * Checks that we have enough buffer space to encode 'nbytes' more | |
634 | * bytes of data. If so, update the total xdr_buf length, and | |
635 | * adjust the length of the current kvec. | |
636 | */ | |
637 | uint32_t * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes) | |
638 | { | |
639 | uint32_t *p = xdr->p; | |
640 | uint32_t *q; | |
641 | ||
642 | /* align nbytes on the next 32-bit boundary */ | |
643 | nbytes += 3; | |
644 | nbytes &= ~3; | |
645 | q = p + (nbytes >> 2); | |
646 | if (unlikely(q > xdr->end || q < p)) | |
647 | return NULL; | |
648 | xdr->p = q; | |
649 | xdr->iov->iov_len += nbytes; | |
650 | xdr->buf->len += nbytes; | |
651 | return p; | |
652 | } | |
653 | EXPORT_SYMBOL(xdr_reserve_space); | |
654 | ||
655 | /** | |
656 | * xdr_write_pages - Insert a list of pages into an XDR buffer for sending | |
657 | * @xdr: pointer to xdr_stream | |
658 | * @pages: list of pages | |
659 | * @base: offset of first byte | |
660 | * @len: length of data in bytes | |
661 | * | |
662 | */ | |
663 | void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base, | |
664 | unsigned int len) | |
665 | { | |
666 | struct xdr_buf *buf = xdr->buf; | |
667 | struct kvec *iov = buf->tail; | |
668 | buf->pages = pages; | |
669 | buf->page_base = base; | |
670 | buf->page_len = len; | |
671 | ||
672 | iov->iov_base = (char *)xdr->p; | |
673 | iov->iov_len = 0; | |
674 | xdr->iov = iov; | |
675 | ||
676 | if (len & 3) { | |
677 | unsigned int pad = 4 - (len & 3); | |
678 | ||
679 | BUG_ON(xdr->p >= xdr->end); | |
680 | iov->iov_base = (char *)xdr->p + (len & 3); | |
681 | iov->iov_len += pad; | |
682 | len += pad; | |
683 | *xdr->p++ = 0; | |
684 | } | |
685 | buf->buflen += len; | |
686 | buf->len += len; | |
687 | } | |
688 | EXPORT_SYMBOL(xdr_write_pages); | |
689 | ||
690 | /** | |
691 | * xdr_init_decode - Initialize an xdr_stream for decoding data. | |
692 | * @xdr: pointer to xdr_stream struct | |
693 | * @buf: pointer to XDR buffer from which to decode data | |
694 | * @p: current pointer inside XDR buffer | |
695 | */ | |
696 | void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, uint32_t *p) | |
697 | { | |
698 | struct kvec *iov = buf->head; | |
699 | unsigned int len = iov->iov_len; | |
700 | ||
701 | if (len > buf->len) | |
702 | len = buf->len; | |
703 | xdr->buf = buf; | |
704 | xdr->iov = iov; | |
705 | xdr->p = p; | |
706 | xdr->end = (uint32_t *)((char *)iov->iov_base + len); | |
707 | } | |
708 | EXPORT_SYMBOL(xdr_init_decode); | |
709 | ||
710 | /** | |
711 | * xdr_inline_decode - Retrieve non-page XDR data to decode | |
712 | * @xdr: pointer to xdr_stream struct | |
713 | * @nbytes: number of bytes of data to decode | |
714 | * | |
715 | * Check if the input buffer is long enough to enable us to decode | |
716 | * 'nbytes' more bytes of data starting at the current position. | |
717 | * If so return the current pointer, then update the current | |
718 | * pointer position. | |
719 | */ | |
720 | uint32_t * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes) | |
721 | { | |
722 | uint32_t *p = xdr->p; | |
723 | uint32_t *q = p + XDR_QUADLEN(nbytes); | |
724 | ||
725 | if (unlikely(q > xdr->end || q < p)) | |
726 | return NULL; | |
727 | xdr->p = q; | |
728 | return p; | |
729 | } | |
730 | EXPORT_SYMBOL(xdr_inline_decode); | |
731 | ||
732 | /** | |
733 | * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position | |
734 | * @xdr: pointer to xdr_stream struct | |
735 | * @len: number of bytes of page data | |
736 | * | |
737 | * Moves data beyond the current pointer position from the XDR head[] buffer | |
738 | * into the page list. Any data that lies beyond current position + "len" | |
739 | * bytes is moved into the XDR tail[]. The current pointer is then | |
740 | * repositioned at the beginning of the XDR tail. | |
741 | */ | |
742 | void xdr_read_pages(struct xdr_stream *xdr, unsigned int len) | |
743 | { | |
744 | struct xdr_buf *buf = xdr->buf; | |
745 | struct kvec *iov; | |
746 | ssize_t shift; | |
747 | unsigned int end; | |
748 | int padding; | |
749 | ||
750 | /* Realign pages to current pointer position */ | |
751 | iov = buf->head; | |
752 | shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p; | |
753 | if (shift > 0) | |
754 | xdr_shrink_bufhead(buf, shift); | |
755 | ||
756 | /* Truncate page data and move it into the tail */ | |
757 | if (buf->page_len > len) | |
758 | xdr_shrink_pagelen(buf, buf->page_len - len); | |
759 | padding = (XDR_QUADLEN(len) << 2) - len; | |
760 | xdr->iov = iov = buf->tail; | |
761 | /* Compute remaining message length. */ | |
762 | end = iov->iov_len; | |
763 | shift = buf->buflen - buf->len; | |
764 | if (shift < end) | |
765 | end -= shift; | |
766 | else if (shift > 0) | |
767 | end = 0; | |
768 | /* | |
769 | * Position current pointer at beginning of tail, and | |
770 | * set remaining message length. | |
771 | */ | |
772 | xdr->p = (uint32_t *)((char *)iov->iov_base + padding); | |
773 | xdr->end = (uint32_t *)((char *)iov->iov_base + end); | |
774 | } | |
775 | EXPORT_SYMBOL(xdr_read_pages); | |
776 | ||
777 | static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0}; | |
778 | ||
779 | void | |
780 | xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf) | |
781 | { | |
782 | buf->head[0] = *iov; | |
783 | buf->tail[0] = empty_iov; | |
784 | buf->page_len = 0; | |
785 | buf->buflen = buf->len = iov->iov_len; | |
786 | } | |
787 | ||
788 | /* Sets subiov to the intersection of iov with the buffer of length len | |
789 | * starting base bytes after iov. Indicates empty intersection by setting | |
790 | * length of subiov to zero. Decrements len by length of subiov, sets base | |
791 | * to zero (or decrements it by length of iov if subiov is empty). */ | |
792 | static void | |
793 | iov_subsegment(struct kvec *iov, struct kvec *subiov, int *base, int *len) | |
794 | { | |
795 | if (*base > iov->iov_len) { | |
796 | subiov->iov_base = NULL; | |
797 | subiov->iov_len = 0; | |
798 | *base -= iov->iov_len; | |
799 | } else { | |
800 | subiov->iov_base = iov->iov_base + *base; | |
801 | subiov->iov_len = min(*len, (int)iov->iov_len - *base); | |
802 | *base = 0; | |
803 | } | |
804 | *len -= subiov->iov_len; | |
805 | } | |
806 | ||
807 | /* Sets subbuf to the portion of buf of length len beginning base bytes | |
808 | * from the start of buf. Returns -1 if base of length are out of bounds. */ | |
809 | int | |
810 | xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, | |
811 | int base, int len) | |
812 | { | |
813 | int i; | |
814 | ||
815 | subbuf->buflen = subbuf->len = len; | |
816 | iov_subsegment(buf->head, subbuf->head, &base, &len); | |
817 | ||
818 | if (base < buf->page_len) { | |
819 | i = (base + buf->page_base) >> PAGE_CACHE_SHIFT; | |
820 | subbuf->pages = &buf->pages[i]; | |
821 | subbuf->page_base = (base + buf->page_base) & ~PAGE_CACHE_MASK; | |
822 | subbuf->page_len = min((int)buf->page_len - base, len); | |
823 | len -= subbuf->page_len; | |
824 | base = 0; | |
825 | } else { | |
826 | base -= buf->page_len; | |
827 | subbuf->page_len = 0; | |
828 | } | |
829 | ||
830 | iov_subsegment(buf->tail, subbuf->tail, &base, &len); | |
831 | if (base || len) | |
832 | return -1; | |
833 | return 0; | |
834 | } | |
835 | ||
836 | /* obj is assumed to point to allocated memory of size at least len: */ | |
837 | int | |
838 | read_bytes_from_xdr_buf(struct xdr_buf *buf, int base, void *obj, int len) | |
839 | { | |
840 | struct xdr_buf subbuf; | |
841 | int this_len; | |
842 | int status; | |
843 | ||
844 | status = xdr_buf_subsegment(buf, &subbuf, base, len); | |
845 | if (status) | |
846 | goto out; | |
847 | this_len = min(len, (int)subbuf.head[0].iov_len); | |
848 | memcpy(obj, subbuf.head[0].iov_base, this_len); | |
849 | len -= this_len; | |
850 | obj += this_len; | |
851 | this_len = min(len, (int)subbuf.page_len); | |
852 | if (this_len) | |
853 | _copy_from_pages(obj, subbuf.pages, subbuf.page_base, this_len); | |
854 | len -= this_len; | |
855 | obj += this_len; | |
856 | this_len = min(len, (int)subbuf.tail[0].iov_len); | |
857 | memcpy(obj, subbuf.tail[0].iov_base, this_len); | |
858 | out: | |
859 | return status; | |
860 | } | |
861 | ||
862 | static int | |
863 | read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj) | |
864 | { | |
865 | u32 raw; | |
866 | int status; | |
867 | ||
868 | status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj)); | |
869 | if (status) | |
870 | return status; | |
871 | *obj = ntohl(raw); | |
872 | return 0; | |
873 | } | |
874 | ||
875 | /* If the netobj starting offset bytes from the start of xdr_buf is contained | |
876 | * entirely in the head or the tail, set object to point to it; otherwise | |
877 | * try to find space for it at the end of the tail, copy it there, and | |
878 | * set obj to point to it. */ | |
879 | int | |
880 | xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, int offset) | |
881 | { | |
882 | u32 tail_offset = buf->head[0].iov_len + buf->page_len; | |
883 | u32 obj_end_offset; | |
884 | ||
885 | if (read_u32_from_xdr_buf(buf, offset, &obj->len)) | |
886 | goto out; | |
887 | obj_end_offset = offset + 4 + obj->len; | |
888 | ||
889 | if (obj_end_offset <= buf->head[0].iov_len) { | |
890 | /* The obj is contained entirely in the head: */ | |
891 | obj->data = buf->head[0].iov_base + offset + 4; | |
892 | } else if (offset + 4 >= tail_offset) { | |
893 | if (obj_end_offset - tail_offset | |
894 | > buf->tail[0].iov_len) | |
895 | goto out; | |
896 | /* The obj is contained entirely in the tail: */ | |
897 | obj->data = buf->tail[0].iov_base | |
898 | + offset - tail_offset + 4; | |
899 | } else { | |
900 | /* use end of tail as storage for obj: | |
901 | * (We don't copy to the beginning because then we'd have | |
902 | * to worry about doing a potentially overlapping copy. | |
903 | * This assumes the object is at most half the length of the | |
904 | * tail.) */ | |
905 | if (obj->len > buf->tail[0].iov_len) | |
906 | goto out; | |
907 | obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len - | |
908 | obj->len; | |
909 | if (read_bytes_from_xdr_buf(buf, offset + 4, | |
910 | obj->data, obj->len)) | |
911 | goto out; | |
912 | ||
913 | } | |
914 | return 0; | |
915 | out: | |
916 | return -1; | |
917 | } |