xref: /linux/fs/nfs/callback_xdr.c (revision 26b0d14106954ae46d2f4f7eec3481828a210f7d)
1 /*
2  * linux/fs/nfs/callback_xdr.c
3  *
4  * Copyright (C) 2004 Trond Myklebust
5  *
6  * NFSv4 callback encode/decode procedures
7  */
8 #include <linux/kernel.h>
9 #include <linux/sunrpc/svc.h>
10 #include <linux/nfs4.h>
11 #include <linux/nfs_fs.h>
12 #include <linux/ratelimit.h>
13 #include <linux/printk.h>
14 #include <linux/slab.h>
15 #include <linux/sunrpc/bc_xprt.h>
16 #include "nfs4_fs.h"
17 #include "callback.h"
18 #include "internal.h"
19 
20 #define CB_OP_TAGLEN_MAXSZ	(512)
21 #define CB_OP_HDR_RES_MAXSZ	(2 + CB_OP_TAGLEN_MAXSZ)
22 #define CB_OP_GETATTR_BITMAP_MAXSZ	(4)
23 #define CB_OP_GETATTR_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
24 				CB_OP_GETATTR_BITMAP_MAXSZ + \
25 				2 + 2 + 3 + 3)
26 #define CB_OP_RECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
27 
28 #if defined(CONFIG_NFS_V4_1)
29 #define CB_OP_LAYOUTRECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
30 #define CB_OP_DEVICENOTIFY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
31 #define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
32 					4 + 1 + 3)
33 #define CB_OP_RECALLANY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
34 #define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
35 #endif /* CONFIG_NFS_V4_1 */
36 
37 #define NFSDBG_FACILITY NFSDBG_CALLBACK
38 
39 /* Internal error code */
40 #define NFS4ERR_RESOURCE_HDR	11050
41 
42 typedef __be32 (*callback_process_op_t)(void *, void *,
43 					struct cb_process_state *);
44 typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
45 typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
46 
47 
48 struct callback_op {
49 	callback_process_op_t process_op;
50 	callback_decode_arg_t decode_args;
51 	callback_encode_res_t encode_res;
52 	long res_maxsize;
53 };
54 
55 static struct callback_op callback_ops[];
56 
57 static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
58 {
59 	return htonl(NFS4_OK);
60 }
61 
62 static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
63 {
64 	return xdr_argsize_check(rqstp, p);
65 }
66 
67 static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
68 {
69 	return xdr_ressize_check(rqstp, p);
70 }
71 
72 static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
73 {
74 	__be32 *p;
75 
76 	p = xdr_inline_decode(xdr, nbytes);
77 	if (unlikely(p == NULL))
78 		printk(KERN_WARNING "NFS: NFSv4 callback reply buffer overflowed!\n");
79 	return p;
80 }
81 
82 static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len, const char **str)
83 {
84 	__be32 *p;
85 
86 	p = read_buf(xdr, 4);
87 	if (unlikely(p == NULL))
88 		return htonl(NFS4ERR_RESOURCE);
89 	*len = ntohl(*p);
90 
91 	if (*len != 0) {
92 		p = read_buf(xdr, *len);
93 		if (unlikely(p == NULL))
94 			return htonl(NFS4ERR_RESOURCE);
95 		*str = (const char *)p;
96 	} else
97 		*str = NULL;
98 
99 	return 0;
100 }
101 
102 static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
103 {
104 	__be32 *p;
105 
106 	p = read_buf(xdr, 4);
107 	if (unlikely(p == NULL))
108 		return htonl(NFS4ERR_RESOURCE);
109 	fh->size = ntohl(*p);
110 	if (fh->size > NFS4_FHSIZE)
111 		return htonl(NFS4ERR_BADHANDLE);
112 	p = read_buf(xdr, fh->size);
113 	if (unlikely(p == NULL))
114 		return htonl(NFS4ERR_RESOURCE);
115 	memcpy(&fh->data[0], p, fh->size);
116 	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
117 	return 0;
118 }
119 
120 static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
121 {
122 	__be32 *p;
123 	unsigned int attrlen;
124 
125 	p = read_buf(xdr, 4);
126 	if (unlikely(p == NULL))
127 		return htonl(NFS4ERR_RESOURCE);
128 	attrlen = ntohl(*p);
129 	p = read_buf(xdr, attrlen << 2);
130 	if (unlikely(p == NULL))
131 		return htonl(NFS4ERR_RESOURCE);
132 	if (likely(attrlen > 0))
133 		bitmap[0] = ntohl(*p++);
134 	if (attrlen > 1)
135 		bitmap[1] = ntohl(*p);
136 	return 0;
137 }
138 
139 static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
140 {
141 	__be32 *p;
142 
143 	p = read_buf(xdr, NFS4_STATEID_SIZE);
144 	if (unlikely(p == NULL))
145 		return htonl(NFS4ERR_RESOURCE);
146 	memcpy(stateid, p, NFS4_STATEID_SIZE);
147 	return 0;
148 }
149 
150 static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
151 {
152 	__be32 *p;
153 	__be32 status;
154 
155 	status = decode_string(xdr, &hdr->taglen, &hdr->tag);
156 	if (unlikely(status != 0))
157 		return status;
158 	/* We do not like overly long tags! */
159 	if (hdr->taglen > CB_OP_TAGLEN_MAXSZ - 12) {
160 		printk("NFS: NFSv4 CALLBACK %s: client sent tag of length %u\n",
161 				__func__, hdr->taglen);
162 		return htonl(NFS4ERR_RESOURCE);
163 	}
164 	p = read_buf(xdr, 12);
165 	if (unlikely(p == NULL))
166 		return htonl(NFS4ERR_RESOURCE);
167 	hdr->minorversion = ntohl(*p++);
168 	/* Check minor version is zero or one. */
169 	if (hdr->minorversion <= 1) {
170 		hdr->cb_ident = ntohl(*p++); /* ignored by v4.1 */
171 	} else {
172 		pr_warn_ratelimited("NFS: %s: NFSv4 server callback with "
173 			"illegal minor version %u!\n",
174 			__func__, hdr->minorversion);
175 		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
176 	}
177 	hdr->nops = ntohl(*p);
178 	dprintk("%s: minorversion %d nops %d\n", __func__,
179 		hdr->minorversion, hdr->nops);
180 	return 0;
181 }
182 
183 static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
184 {
185 	__be32 *p;
186 	p = read_buf(xdr, 4);
187 	if (unlikely(p == NULL))
188 		return htonl(NFS4ERR_RESOURCE_HDR);
189 	*op = ntohl(*p);
190 	return 0;
191 }
192 
193 static __be32 decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
194 {
195 	__be32 status;
196 
197 	status = decode_fh(xdr, &args->fh);
198 	if (unlikely(status != 0))
199 		goto out;
200 	args->addr = svc_addr(rqstp);
201 	status = decode_bitmap(xdr, args->bitmap);
202 out:
203 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
204 	return status;
205 }
206 
207 static __be32 decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
208 {
209 	__be32 *p;
210 	__be32 status;
211 
212 	args->addr = svc_addr(rqstp);
213 	status = decode_stateid(xdr, &args->stateid);
214 	if (unlikely(status != 0))
215 		goto out;
216 	p = read_buf(xdr, 4);
217 	if (unlikely(p == NULL)) {
218 		status = htonl(NFS4ERR_RESOURCE);
219 		goto out;
220 	}
221 	args->truncate = ntohl(*p);
222 	status = decode_fh(xdr, &args->fh);
223 out:
224 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
225 	return status;
226 }
227 
228 #if defined(CONFIG_NFS_V4_1)
229 
230 static __be32 decode_layoutrecall_args(struct svc_rqst *rqstp,
231 				       struct xdr_stream *xdr,
232 				       struct cb_layoutrecallargs *args)
233 {
234 	__be32 *p;
235 	__be32 status = 0;
236 	uint32_t iomode;
237 
238 	args->cbl_addr = svc_addr(rqstp);
239 	p = read_buf(xdr, 4 * sizeof(uint32_t));
240 	if (unlikely(p == NULL)) {
241 		status = htonl(NFS4ERR_BADXDR);
242 		goto out;
243 	}
244 
245 	args->cbl_layout_type = ntohl(*p++);
246 	/* Depite the spec's xdr, iomode really belongs in the FILE switch,
247 	 * as it is unusable and ignored with the other types.
248 	 */
249 	iomode = ntohl(*p++);
250 	args->cbl_layoutchanged = ntohl(*p++);
251 	args->cbl_recall_type = ntohl(*p++);
252 
253 	if (args->cbl_recall_type == RETURN_FILE) {
254 		args->cbl_range.iomode = iomode;
255 		status = decode_fh(xdr, &args->cbl_fh);
256 		if (unlikely(status != 0))
257 			goto out;
258 
259 		p = read_buf(xdr, 2 * sizeof(uint64_t));
260 		if (unlikely(p == NULL)) {
261 			status = htonl(NFS4ERR_BADXDR);
262 			goto out;
263 		}
264 		p = xdr_decode_hyper(p, &args->cbl_range.offset);
265 		p = xdr_decode_hyper(p, &args->cbl_range.length);
266 		status = decode_stateid(xdr, &args->cbl_stateid);
267 		if (unlikely(status != 0))
268 			goto out;
269 	} else if (args->cbl_recall_type == RETURN_FSID) {
270 		p = read_buf(xdr, 2 * sizeof(uint64_t));
271 		if (unlikely(p == NULL)) {
272 			status = htonl(NFS4ERR_BADXDR);
273 			goto out;
274 		}
275 		p = xdr_decode_hyper(p, &args->cbl_fsid.major);
276 		p = xdr_decode_hyper(p, &args->cbl_fsid.minor);
277 	} else if (args->cbl_recall_type != RETURN_ALL) {
278 		status = htonl(NFS4ERR_BADXDR);
279 		goto out;
280 	}
281 	dprintk("%s: ltype 0x%x iomode %d changed %d recall_type %d\n",
282 		__func__,
283 		args->cbl_layout_type, iomode,
284 		args->cbl_layoutchanged, args->cbl_recall_type);
285 out:
286 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
287 	return status;
288 }
289 
290 static
291 __be32 decode_devicenotify_args(struct svc_rqst *rqstp,
292 				struct xdr_stream *xdr,
293 				struct cb_devicenotifyargs *args)
294 {
295 	__be32 *p;
296 	__be32 status = 0;
297 	u32 tmp;
298 	int n, i;
299 	args->ndevs = 0;
300 
301 	/* Num of device notifications */
302 	p = read_buf(xdr, sizeof(uint32_t));
303 	if (unlikely(p == NULL)) {
304 		status = htonl(NFS4ERR_BADXDR);
305 		goto out;
306 	}
307 	n = ntohl(*p++);
308 	if (n <= 0)
309 		goto out;
310 	if (n > ULONG_MAX / sizeof(*args->devs)) {
311 		status = htonl(NFS4ERR_BADXDR);
312 		goto out;
313 	}
314 
315 	args->devs = kmalloc(n * sizeof(*args->devs), GFP_KERNEL);
316 	if (!args->devs) {
317 		status = htonl(NFS4ERR_DELAY);
318 		goto out;
319 	}
320 
321 	/* Decode each dev notification */
322 	for (i = 0; i < n; i++) {
323 		struct cb_devicenotifyitem *dev = &args->devs[i];
324 
325 		p = read_buf(xdr, (4 * sizeof(uint32_t)) + NFS4_DEVICEID4_SIZE);
326 		if (unlikely(p == NULL)) {
327 			status = htonl(NFS4ERR_BADXDR);
328 			goto err;
329 		}
330 
331 		tmp = ntohl(*p++);	/* bitmap size */
332 		if (tmp != 1) {
333 			status = htonl(NFS4ERR_INVAL);
334 			goto err;
335 		}
336 		dev->cbd_notify_type = ntohl(*p++);
337 		if (dev->cbd_notify_type != NOTIFY_DEVICEID4_CHANGE &&
338 		    dev->cbd_notify_type != NOTIFY_DEVICEID4_DELETE) {
339 			status = htonl(NFS4ERR_INVAL);
340 			goto err;
341 		}
342 
343 		tmp = ntohl(*p++);	/* opaque size */
344 		if (((dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE) &&
345 		     (tmp != NFS4_DEVICEID4_SIZE + 8)) ||
346 		    ((dev->cbd_notify_type == NOTIFY_DEVICEID4_DELETE) &&
347 		     (tmp != NFS4_DEVICEID4_SIZE + 4))) {
348 			status = htonl(NFS4ERR_INVAL);
349 			goto err;
350 		}
351 		dev->cbd_layout_type = ntohl(*p++);
352 		memcpy(dev->cbd_dev_id.data, p, NFS4_DEVICEID4_SIZE);
353 		p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
354 
355 		if (dev->cbd_layout_type == NOTIFY_DEVICEID4_CHANGE) {
356 			p = read_buf(xdr, sizeof(uint32_t));
357 			if (unlikely(p == NULL)) {
358 				status = htonl(NFS4ERR_BADXDR);
359 				goto err;
360 			}
361 			dev->cbd_immediate = ntohl(*p++);
362 		} else {
363 			dev->cbd_immediate = 0;
364 		}
365 
366 		args->ndevs++;
367 
368 		dprintk("%s: type %d layout 0x%x immediate %d\n",
369 			__func__, dev->cbd_notify_type, dev->cbd_layout_type,
370 			dev->cbd_immediate);
371 	}
372 out:
373 	dprintk("%s: status %d ndevs %d\n",
374 		__func__, ntohl(status), args->ndevs);
375 	return status;
376 err:
377 	kfree(args->devs);
378 	goto out;
379 }
380 
381 static __be32 decode_sessionid(struct xdr_stream *xdr,
382 				 struct nfs4_sessionid *sid)
383 {
384 	__be32 *p;
385 	int len = NFS4_MAX_SESSIONID_LEN;
386 
387 	p = read_buf(xdr, len);
388 	if (unlikely(p == NULL))
389 		return htonl(NFS4ERR_RESOURCE);
390 
391 	memcpy(sid->data, p, len);
392 	return 0;
393 }
394 
395 static __be32 decode_rc_list(struct xdr_stream *xdr,
396 			       struct referring_call_list *rc_list)
397 {
398 	__be32 *p;
399 	int i;
400 	__be32 status;
401 
402 	status = decode_sessionid(xdr, &rc_list->rcl_sessionid);
403 	if (status)
404 		goto out;
405 
406 	status = htonl(NFS4ERR_RESOURCE);
407 	p = read_buf(xdr, sizeof(uint32_t));
408 	if (unlikely(p == NULL))
409 		goto out;
410 
411 	rc_list->rcl_nrefcalls = ntohl(*p++);
412 	if (rc_list->rcl_nrefcalls) {
413 		p = read_buf(xdr,
414 			     rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
415 		if (unlikely(p == NULL))
416 			goto out;
417 		rc_list->rcl_refcalls = kmalloc(rc_list->rcl_nrefcalls *
418 						sizeof(*rc_list->rcl_refcalls),
419 						GFP_KERNEL);
420 		if (unlikely(rc_list->rcl_refcalls == NULL))
421 			goto out;
422 		for (i = 0; i < rc_list->rcl_nrefcalls; i++) {
423 			rc_list->rcl_refcalls[i].rc_sequenceid = ntohl(*p++);
424 			rc_list->rcl_refcalls[i].rc_slotid = ntohl(*p++);
425 		}
426 	}
427 	status = 0;
428 
429 out:
430 	return status;
431 }
432 
433 static __be32 decode_cb_sequence_args(struct svc_rqst *rqstp,
434 					struct xdr_stream *xdr,
435 					struct cb_sequenceargs *args)
436 {
437 	__be32 *p;
438 	int i;
439 	__be32 status;
440 
441 	status = decode_sessionid(xdr, &args->csa_sessionid);
442 	if (status)
443 		goto out;
444 
445 	status = htonl(NFS4ERR_RESOURCE);
446 	p = read_buf(xdr, 5 * sizeof(uint32_t));
447 	if (unlikely(p == NULL))
448 		goto out;
449 
450 	args->csa_addr = svc_addr(rqstp);
451 	args->csa_sequenceid = ntohl(*p++);
452 	args->csa_slotid = ntohl(*p++);
453 	args->csa_highestslotid = ntohl(*p++);
454 	args->csa_cachethis = ntohl(*p++);
455 	args->csa_nrclists = ntohl(*p++);
456 	args->csa_rclists = NULL;
457 	if (args->csa_nrclists) {
458 		args->csa_rclists = kmalloc_array(args->csa_nrclists,
459 						  sizeof(*args->csa_rclists),
460 						  GFP_KERNEL);
461 		if (unlikely(args->csa_rclists == NULL))
462 			goto out;
463 
464 		for (i = 0; i < args->csa_nrclists; i++) {
465 			status = decode_rc_list(xdr, &args->csa_rclists[i]);
466 			if (status)
467 				goto out_free;
468 		}
469 	}
470 	status = 0;
471 
472 	dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u slotid %u "
473 		"highestslotid %u cachethis %d nrclists %u\n",
474 		__func__,
475 		((u32 *)&args->csa_sessionid)[0],
476 		((u32 *)&args->csa_sessionid)[1],
477 		((u32 *)&args->csa_sessionid)[2],
478 		((u32 *)&args->csa_sessionid)[3],
479 		args->csa_sequenceid, args->csa_slotid,
480 		args->csa_highestslotid, args->csa_cachethis,
481 		args->csa_nrclists);
482 out:
483 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
484 	return status;
485 
486 out_free:
487 	for (i = 0; i < args->csa_nrclists; i++)
488 		kfree(args->csa_rclists[i].rcl_refcalls);
489 	kfree(args->csa_rclists);
490 	goto out;
491 }
492 
493 static __be32 decode_recallany_args(struct svc_rqst *rqstp,
494 				      struct xdr_stream *xdr,
495 				      struct cb_recallanyargs *args)
496 {
497 	uint32_t bitmap[2];
498 	__be32 *p, status;
499 
500 	args->craa_addr = svc_addr(rqstp);
501 	p = read_buf(xdr, 4);
502 	if (unlikely(p == NULL))
503 		return htonl(NFS4ERR_BADXDR);
504 	args->craa_objs_to_keep = ntohl(*p++);
505 	status = decode_bitmap(xdr, bitmap);
506 	if (unlikely(status))
507 		return status;
508 	args->craa_type_mask = bitmap[0];
509 
510 	return 0;
511 }
512 
513 static __be32 decode_recallslot_args(struct svc_rqst *rqstp,
514 					struct xdr_stream *xdr,
515 					struct cb_recallslotargs *args)
516 {
517 	__be32 *p;
518 
519 	args->crsa_addr = svc_addr(rqstp);
520 	p = read_buf(xdr, 4);
521 	if (unlikely(p == NULL))
522 		return htonl(NFS4ERR_BADXDR);
523 	args->crsa_target_max_slots = ntohl(*p++);
524 	return 0;
525 }
526 
527 #endif /* CONFIG_NFS_V4_1 */
528 
529 static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
530 {
531 	__be32 *p;
532 
533 	p = xdr_reserve_space(xdr, 4 + len);
534 	if (unlikely(p == NULL))
535 		return htonl(NFS4ERR_RESOURCE);
536 	xdr_encode_opaque(p, str, len);
537 	return 0;
538 }
539 
540 #define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
541 #define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
542 static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, __be32 **savep)
543 {
544 	__be32 bm[2];
545 	__be32 *p;
546 
547 	bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
548 	bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
549 	if (bm[1] != 0) {
550 		p = xdr_reserve_space(xdr, 16);
551 		if (unlikely(p == NULL))
552 			return htonl(NFS4ERR_RESOURCE);
553 		*p++ = htonl(2);
554 		*p++ = bm[0];
555 		*p++ = bm[1];
556 	} else if (bm[0] != 0) {
557 		p = xdr_reserve_space(xdr, 12);
558 		if (unlikely(p == NULL))
559 			return htonl(NFS4ERR_RESOURCE);
560 		*p++ = htonl(1);
561 		*p++ = bm[0];
562 	} else {
563 		p = xdr_reserve_space(xdr, 8);
564 		if (unlikely(p == NULL))
565 			return htonl(NFS4ERR_RESOURCE);
566 		*p++ = htonl(0);
567 	}
568 	*savep = p;
569 	return 0;
570 }
571 
572 static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
573 {
574 	__be32 *p;
575 
576 	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
577 		return 0;
578 	p = xdr_reserve_space(xdr, 8);
579 	if (unlikely(!p))
580 		return htonl(NFS4ERR_RESOURCE);
581 	p = xdr_encode_hyper(p, change);
582 	return 0;
583 }
584 
585 static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
586 {
587 	__be32 *p;
588 
589 	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
590 		return 0;
591 	p = xdr_reserve_space(xdr, 8);
592 	if (unlikely(!p))
593 		return htonl(NFS4ERR_RESOURCE);
594 	p = xdr_encode_hyper(p, size);
595 	return 0;
596 }
597 
598 static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
599 {
600 	__be32 *p;
601 
602 	p = xdr_reserve_space(xdr, 12);
603 	if (unlikely(!p))
604 		return htonl(NFS4ERR_RESOURCE);
605 	p = xdr_encode_hyper(p, time->tv_sec);
606 	*p = htonl(time->tv_nsec);
607 	return 0;
608 }
609 
610 static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
611 {
612 	if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
613 		return 0;
614 	return encode_attr_time(xdr,time);
615 }
616 
617 static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
618 {
619 	if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
620 		return 0;
621 	return encode_attr_time(xdr,time);
622 }
623 
624 static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
625 {
626 	__be32 status;
627 
628 	hdr->status = xdr_reserve_space(xdr, 4);
629 	if (unlikely(hdr->status == NULL))
630 		return htonl(NFS4ERR_RESOURCE);
631 	status = encode_string(xdr, hdr->taglen, hdr->tag);
632 	if (unlikely(status != 0))
633 		return status;
634 	hdr->nops = xdr_reserve_space(xdr, 4);
635 	if (unlikely(hdr->nops == NULL))
636 		return htonl(NFS4ERR_RESOURCE);
637 	return 0;
638 }
639 
640 static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
641 {
642 	__be32 *p;
643 
644 	p = xdr_reserve_space(xdr, 8);
645 	if (unlikely(p == NULL))
646 		return htonl(NFS4ERR_RESOURCE_HDR);
647 	*p++ = htonl(op);
648 	*p = res;
649 	return 0;
650 }
651 
652 static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
653 {
654 	__be32 *savep = NULL;
655 	__be32 status = res->status;
656 
657 	if (unlikely(status != 0))
658 		goto out;
659 	status = encode_attr_bitmap(xdr, res->bitmap, &savep);
660 	if (unlikely(status != 0))
661 		goto out;
662 	status = encode_attr_change(xdr, res->bitmap, res->change_attr);
663 	if (unlikely(status != 0))
664 		goto out;
665 	status = encode_attr_size(xdr, res->bitmap, res->size);
666 	if (unlikely(status != 0))
667 		goto out;
668 	status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
669 	if (unlikely(status != 0))
670 		goto out;
671 	status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
672 	*savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
673 out:
674 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
675 	return status;
676 }
677 
678 #if defined(CONFIG_NFS_V4_1)
679 
680 static __be32 encode_sessionid(struct xdr_stream *xdr,
681 				 const struct nfs4_sessionid *sid)
682 {
683 	__be32 *p;
684 	int len = NFS4_MAX_SESSIONID_LEN;
685 
686 	p = xdr_reserve_space(xdr, len);
687 	if (unlikely(p == NULL))
688 		return htonl(NFS4ERR_RESOURCE);
689 
690 	memcpy(p, sid, len);
691 	return 0;
692 }
693 
694 static __be32 encode_cb_sequence_res(struct svc_rqst *rqstp,
695 				       struct xdr_stream *xdr,
696 				       const struct cb_sequenceres *res)
697 {
698 	__be32 *p;
699 	__be32 status = res->csr_status;
700 
701 	if (unlikely(status != 0))
702 		goto out;
703 
704 	encode_sessionid(xdr, &res->csr_sessionid);
705 
706 	p = xdr_reserve_space(xdr, 4 * sizeof(uint32_t));
707 	if (unlikely(p == NULL))
708 		return htonl(NFS4ERR_RESOURCE);
709 
710 	*p++ = htonl(res->csr_sequenceid);
711 	*p++ = htonl(res->csr_slotid);
712 	*p++ = htonl(res->csr_highestslotid);
713 	*p++ = htonl(res->csr_target_highestslotid);
714 out:
715 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
716 	return status;
717 }
718 
719 static __be32
720 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
721 {
722 	if (op_nr == OP_CB_SEQUENCE) {
723 		if (nop != 0)
724 			return htonl(NFS4ERR_SEQUENCE_POS);
725 	} else {
726 		if (nop == 0)
727 			return htonl(NFS4ERR_OP_NOT_IN_SESSION);
728 	}
729 
730 	switch (op_nr) {
731 	case OP_CB_GETATTR:
732 	case OP_CB_RECALL:
733 	case OP_CB_SEQUENCE:
734 	case OP_CB_RECALL_ANY:
735 	case OP_CB_RECALL_SLOT:
736 	case OP_CB_LAYOUTRECALL:
737 	case OP_CB_NOTIFY_DEVICEID:
738 		*op = &callback_ops[op_nr];
739 		break;
740 
741 	case OP_CB_NOTIFY:
742 	case OP_CB_PUSH_DELEG:
743 	case OP_CB_RECALLABLE_OBJ_AVAIL:
744 	case OP_CB_WANTS_CANCELLED:
745 	case OP_CB_NOTIFY_LOCK:
746 		return htonl(NFS4ERR_NOTSUPP);
747 
748 	default:
749 		return htonl(NFS4ERR_OP_ILLEGAL);
750 	}
751 
752 	return htonl(NFS_OK);
753 }
754 
755 static void nfs4_callback_free_slot(struct nfs4_session *session)
756 {
757 	struct nfs4_slot_table *tbl = &session->bc_slot_table;
758 
759 	spin_lock(&tbl->slot_tbl_lock);
760 	/*
761 	 * Let the state manager know callback processing done.
762 	 * A single slot, so highest used slotid is either 0 or -1
763 	 */
764 	tbl->highest_used_slotid = NFS4_NO_SLOT;
765 	nfs4_check_drain_bc_complete(session);
766 	spin_unlock(&tbl->slot_tbl_lock);
767 }
768 
769 static void nfs4_cb_free_slot(struct cb_process_state *cps)
770 {
771 	if (cps->slotid != NFS4_NO_SLOT)
772 		nfs4_callback_free_slot(cps->clp->cl_session);
773 }
774 
775 #else /* CONFIG_NFS_V4_1 */
776 
777 static __be32
778 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
779 {
780 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
781 }
782 
783 static void nfs4_cb_free_slot(struct cb_process_state *cps)
784 {
785 }
786 #endif /* CONFIG_NFS_V4_1 */
787 
788 static __be32
789 preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
790 {
791 	switch (op_nr) {
792 	case OP_CB_GETATTR:
793 	case OP_CB_RECALL:
794 		*op = &callback_ops[op_nr];
795 		break;
796 	default:
797 		return htonl(NFS4ERR_OP_ILLEGAL);
798 	}
799 
800 	return htonl(NFS_OK);
801 }
802 
803 static __be32 process_op(uint32_t minorversion, int nop,
804 		struct svc_rqst *rqstp,
805 		struct xdr_stream *xdr_in, void *argp,
806 		struct xdr_stream *xdr_out, void *resp,
807 		struct cb_process_state *cps)
808 {
809 	struct callback_op *op = &callback_ops[0];
810 	unsigned int op_nr;
811 	__be32 status;
812 	long maxlen;
813 	__be32 res;
814 
815 	dprintk("%s: start\n", __func__);
816 	status = decode_op_hdr(xdr_in, &op_nr);
817 	if (unlikely(status))
818 		return status;
819 
820 	dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
821 		__func__, minorversion, nop, op_nr);
822 
823 	status = minorversion ? preprocess_nfs41_op(nop, op_nr, &op) :
824 				preprocess_nfs4_op(op_nr, &op);
825 	if (status == htonl(NFS4ERR_OP_ILLEGAL))
826 		op_nr = OP_CB_ILLEGAL;
827 	if (status)
828 		goto encode_hdr;
829 
830 	if (cps->drc_status) {
831 		status = cps->drc_status;
832 		goto encode_hdr;
833 	}
834 
835 	maxlen = xdr_out->end - xdr_out->p;
836 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
837 		status = op->decode_args(rqstp, xdr_in, argp);
838 		if (likely(status == 0))
839 			status = op->process_op(argp, resp, cps);
840 	} else
841 		status = htonl(NFS4ERR_RESOURCE);
842 
843 encode_hdr:
844 	res = encode_op_hdr(xdr_out, op_nr, status);
845 	if (unlikely(res))
846 		return res;
847 	if (op->encode_res != NULL && status == 0)
848 		status = op->encode_res(rqstp, xdr_out, resp);
849 	dprintk("%s: done, status = %d\n", __func__, ntohl(status));
850 	return status;
851 }
852 
853 /*
854  * Decode, process and encode a COMPOUND
855  */
856 static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
857 {
858 	struct cb_compound_hdr_arg hdr_arg = { 0 };
859 	struct cb_compound_hdr_res hdr_res = { NULL };
860 	struct xdr_stream xdr_in, xdr_out;
861 	__be32 *p, status;
862 	struct cb_process_state cps = {
863 		.drc_status = 0,
864 		.clp = NULL,
865 		.slotid = NFS4_NO_SLOT,
866 		.net = rqstp->rq_xprt->xpt_net,
867 	};
868 	unsigned int nops = 0;
869 
870 	dprintk("%s: start\n", __func__);
871 
872 	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
873 
874 	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
875 	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
876 
877 	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
878 	if (status == __constant_htonl(NFS4ERR_RESOURCE))
879 		return rpc_garbage_args;
880 
881 	if (hdr_arg.minorversion == 0) {
882 		cps.clp = nfs4_find_client_ident(rqstp->rq_xprt->xpt_net, hdr_arg.cb_ident);
883 		if (!cps.clp || !check_gss_callback_principal(cps.clp, rqstp))
884 			return rpc_drop_reply;
885 	}
886 
887 	hdr_res.taglen = hdr_arg.taglen;
888 	hdr_res.tag = hdr_arg.tag;
889 	if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
890 		return rpc_system_err;
891 
892 	while (status == 0 && nops != hdr_arg.nops) {
893 		status = process_op(hdr_arg.minorversion, nops, rqstp,
894 				    &xdr_in, argp, &xdr_out, resp, &cps);
895 		nops++;
896 	}
897 
898 	/* Buffer overflow in decode_ops_hdr or encode_ops_hdr. Return
899 	* resource error in cb_compound status without returning op */
900 	if (unlikely(status == htonl(NFS4ERR_RESOURCE_HDR))) {
901 		status = htonl(NFS4ERR_RESOURCE);
902 		nops--;
903 	}
904 
905 	*hdr_res.status = status;
906 	*hdr_res.nops = htonl(nops);
907 	nfs4_cb_free_slot(&cps);
908 	nfs_put_client(cps.clp);
909 	dprintk("%s: done, status = %u\n", __func__, ntohl(status));
910 	return rpc_success;
911 }
912 
913 /*
914  * Define NFS4 callback COMPOUND ops.
915  */
916 static struct callback_op callback_ops[] = {
917 	[0] = {
918 		.res_maxsize = CB_OP_HDR_RES_MAXSZ,
919 	},
920 	[OP_CB_GETATTR] = {
921 		.process_op = (callback_process_op_t)nfs4_callback_getattr,
922 		.decode_args = (callback_decode_arg_t)decode_getattr_args,
923 		.encode_res = (callback_encode_res_t)encode_getattr_res,
924 		.res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
925 	},
926 	[OP_CB_RECALL] = {
927 		.process_op = (callback_process_op_t)nfs4_callback_recall,
928 		.decode_args = (callback_decode_arg_t)decode_recall_args,
929 		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
930 	},
931 #if defined(CONFIG_NFS_V4_1)
932 	[OP_CB_LAYOUTRECALL] = {
933 		.process_op = (callback_process_op_t)nfs4_callback_layoutrecall,
934 		.decode_args =
935 			(callback_decode_arg_t)decode_layoutrecall_args,
936 		.res_maxsize = CB_OP_LAYOUTRECALL_RES_MAXSZ,
937 	},
938 	[OP_CB_NOTIFY_DEVICEID] = {
939 		.process_op = (callback_process_op_t)nfs4_callback_devicenotify,
940 		.decode_args =
941 			(callback_decode_arg_t)decode_devicenotify_args,
942 		.res_maxsize = CB_OP_DEVICENOTIFY_RES_MAXSZ,
943 	},
944 	[OP_CB_SEQUENCE] = {
945 		.process_op = (callback_process_op_t)nfs4_callback_sequence,
946 		.decode_args = (callback_decode_arg_t)decode_cb_sequence_args,
947 		.encode_res = (callback_encode_res_t)encode_cb_sequence_res,
948 		.res_maxsize = CB_OP_SEQUENCE_RES_MAXSZ,
949 	},
950 	[OP_CB_RECALL_ANY] = {
951 		.process_op = (callback_process_op_t)nfs4_callback_recallany,
952 		.decode_args = (callback_decode_arg_t)decode_recallany_args,
953 		.res_maxsize = CB_OP_RECALLANY_RES_MAXSZ,
954 	},
955 	[OP_CB_RECALL_SLOT] = {
956 		.process_op = (callback_process_op_t)nfs4_callback_recallslot,
957 		.decode_args = (callback_decode_arg_t)decode_recallslot_args,
958 		.res_maxsize = CB_OP_RECALLSLOT_RES_MAXSZ,
959 	},
960 #endif /* CONFIG_NFS_V4_1 */
961 };
962 
963 /*
964  * Define NFS4 callback procedures
965  */
966 static struct svc_procedure nfs4_callback_procedures1[] = {
967 	[CB_NULL] = {
968 		.pc_func = nfs4_callback_null,
969 		.pc_decode = (kxdrproc_t)nfs4_decode_void,
970 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
971 		.pc_xdrressize = 1,
972 	},
973 	[CB_COMPOUND] = {
974 		.pc_func = nfs4_callback_compound,
975 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
976 		.pc_argsize = 256,
977 		.pc_ressize = 256,
978 		.pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
979 	}
980 };
981 
982 struct svc_version nfs4_callback_version1 = {
983 	.vs_vers = 1,
984 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
985 	.vs_proc = nfs4_callback_procedures1,
986 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
987 	.vs_dispatch = NULL,
988 	.vs_hidden = 1,
989 };
990 
991 struct svc_version nfs4_callback_version4 = {
992 	.vs_vers = 4,
993 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
994 	.vs_proc = nfs4_callback_procedures1,
995 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
996 	.vs_dispatch = NULL,
997 	.vs_hidden = 1,
998 };
999