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 "nfs4_fs.h"
13#include "callback.h"
14
15#define CB_OP_TAGLEN_MAXSZ	(512)
16#define CB_OP_HDR_RES_MAXSZ	(2 + CB_OP_TAGLEN_MAXSZ)
17#define CB_OP_GETATTR_BITMAP_MAXSZ	(4)
18#define CB_OP_GETATTR_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
19				CB_OP_GETATTR_BITMAP_MAXSZ + \
20				2 + 2 + 3 + 3)
21#define CB_OP_RECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
22
23#define NFSDBG_FACILITY NFSDBG_CALLBACK
24
25typedef __be32 (*callback_process_op_t)(void *, void *);
26typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
27typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
28
29
30struct callback_op {
31	callback_process_op_t process_op;
32	callback_decode_arg_t decode_args;
33	callback_encode_res_t encode_res;
34	long res_maxsize;
35};
36
37static struct callback_op callback_ops[];
38
39static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
40{
41	return htonl(NFS4_OK);
42}
43
44static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
45{
46	return xdr_argsize_check(rqstp, p);
47}
48
49static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
50{
51	return xdr_ressize_check(rqstp, p);
52}
53
54static __be32 *read_buf(struct xdr_stream *xdr, int nbytes)
55{
56	__be32 *p;
57
58	p = xdr_inline_decode(xdr, nbytes);
59	if (unlikely(p == NULL))
60		printk(KERN_WARNING "NFSv4 callback reply buffer overflowed!\n");
61	return p;
62}
63
64static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len, const char **str)
65{
66	__be32 *p;
67
68	p = read_buf(xdr, 4);
69	if (unlikely(p == NULL))
70		return htonl(NFS4ERR_RESOURCE);
71	*len = ntohl(*p);
72
73	if (*len != 0) {
74		p = read_buf(xdr, *len);
75		if (unlikely(p == NULL))
76			return htonl(NFS4ERR_RESOURCE);
77		*str = (const char *)p;
78	} else
79		*str = NULL;
80
81	return 0;
82}
83
84static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
85{
86	__be32 *p;
87
88	p = read_buf(xdr, 4);
89	if (unlikely(p == NULL))
90		return htonl(NFS4ERR_RESOURCE);
91	fh->size = ntohl(*p);
92	if (fh->size > NFS4_FHSIZE)
93		return htonl(NFS4ERR_BADHANDLE);
94	p = read_buf(xdr, fh->size);
95	if (unlikely(p == NULL))
96		return htonl(NFS4ERR_RESOURCE);
97	memcpy(&fh->data[0], p, fh->size);
98	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
99	return 0;
100}
101
102static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
103{
104	__be32 *p;
105	unsigned int attrlen;
106
107	p = read_buf(xdr, 4);
108	if (unlikely(p == NULL))
109		return htonl(NFS4ERR_RESOURCE);
110	attrlen = ntohl(*p);
111	p = read_buf(xdr, attrlen << 2);
112	if (unlikely(p == NULL))
113		return htonl(NFS4ERR_RESOURCE);
114	if (likely(attrlen > 0))
115		bitmap[0] = ntohl(*p++);
116	if (attrlen > 1)
117		bitmap[1] = ntohl(*p);
118	return 0;
119}
120
121static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
122{
123	__be32 *p;
124
125	p = read_buf(xdr, 16);
126	if (unlikely(p == NULL))
127		return htonl(NFS4ERR_RESOURCE);
128	memcpy(stateid->data, p, 16);
129	return 0;
130}
131
132static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
133{
134	__be32 *p;
135	unsigned int minor_version;
136	__be32 status;
137
138	status = decode_string(xdr, &hdr->taglen, &hdr->tag);
139	if (unlikely(status != 0))
140		return status;
141	/* We do not like overly long tags! */
142	if (hdr->taglen > CB_OP_TAGLEN_MAXSZ-12 || hdr->taglen < 0) {
143		printk("NFSv4 CALLBACK %s: client sent tag of length %u\n",
144				__FUNCTION__, hdr->taglen);
145		return htonl(NFS4ERR_RESOURCE);
146	}
147	p = read_buf(xdr, 12);
148	if (unlikely(p == NULL))
149		return htonl(NFS4ERR_RESOURCE);
150	minor_version = ntohl(*p++);
151	/* Check minor version is zero. */
152	if (minor_version != 0) {
153		printk(KERN_WARNING "%s: NFSv4 server callback with illegal minor version %u!\n",
154				__FUNCTION__, minor_version);
155		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
156	}
157	hdr->callback_ident = ntohl(*p++);
158	hdr->nops = ntohl(*p);
159	return 0;
160}
161
162static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
163{
164	__be32 *p;
165	p = read_buf(xdr, 4);
166	if (unlikely(p == NULL))
167		return htonl(NFS4ERR_RESOURCE);
168	*op = ntohl(*p);
169	return 0;
170}
171
172static __be32 decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
173{
174	__be32 status;
175
176	status = decode_fh(xdr, &args->fh);
177	if (unlikely(status != 0))
178		goto out;
179	args->addr = svc_addr_in(rqstp);
180	status = decode_bitmap(xdr, args->bitmap);
181out:
182	dprintk("%s: exit with status = %d\n", __FUNCTION__, status);
183	return status;
184}
185
186static __be32 decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
187{
188	__be32 *p;
189	__be32 status;
190
191	args->addr = svc_addr_in(rqstp);
192	status = decode_stateid(xdr, &args->stateid);
193	if (unlikely(status != 0))
194		goto out;
195	p = read_buf(xdr, 4);
196	if (unlikely(p == NULL)) {
197		status = htonl(NFS4ERR_RESOURCE);
198		goto out;
199	}
200	args->truncate = ntohl(*p);
201	status = decode_fh(xdr, &args->fh);
202out:
203	dprintk("%s: exit with status = %d\n", __FUNCTION__, status);
204	return status;
205}
206
207static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
208{
209	__be32 *p;
210
211	p = xdr_reserve_space(xdr, 4 + len);
212	if (unlikely(p == NULL))
213		return htonl(NFS4ERR_RESOURCE);
214	xdr_encode_opaque(p, str, len);
215	return 0;
216}
217
218#define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
219#define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
220static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, __be32 **savep)
221{
222	__be32 bm[2];
223	__be32 *p;
224
225	bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
226	bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
227	if (bm[1] != 0) {
228		p = xdr_reserve_space(xdr, 16);
229		if (unlikely(p == NULL))
230			return htonl(NFS4ERR_RESOURCE);
231		*p++ = htonl(2);
232		*p++ = bm[0];
233		*p++ = bm[1];
234	} else if (bm[0] != 0) {
235		p = xdr_reserve_space(xdr, 12);
236		if (unlikely(p == NULL))
237			return htonl(NFS4ERR_RESOURCE);
238		*p++ = htonl(1);
239		*p++ = bm[0];
240	} else {
241		p = xdr_reserve_space(xdr, 8);
242		if (unlikely(p == NULL))
243			return htonl(NFS4ERR_RESOURCE);
244		*p++ = htonl(0);
245	}
246	*savep = p;
247	return 0;
248}
249
250static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
251{
252	__be32 *p;
253
254	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
255		return 0;
256	p = xdr_reserve_space(xdr, 8);
257	if (unlikely(p == 0))
258		return htonl(NFS4ERR_RESOURCE);
259	p = xdr_encode_hyper(p, change);
260	return 0;
261}
262
263static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
264{
265	__be32 *p;
266
267	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
268		return 0;
269	p = xdr_reserve_space(xdr, 8);
270	if (unlikely(p == 0))
271		return htonl(NFS4ERR_RESOURCE);
272	p = xdr_encode_hyper(p, size);
273	return 0;
274}
275
276static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
277{
278	__be32 *p;
279
280	p = xdr_reserve_space(xdr, 12);
281	if (unlikely(p == 0))
282		return htonl(NFS4ERR_RESOURCE);
283	p = xdr_encode_hyper(p, time->tv_sec);
284	*p = htonl(time->tv_nsec);
285	return 0;
286}
287
288static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
289{
290	if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
291		return 0;
292	return encode_attr_time(xdr,time);
293}
294
295static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
296{
297	if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
298		return 0;
299	return encode_attr_time(xdr,time);
300}
301
302static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
303{
304	__be32 status;
305
306	hdr->status = xdr_reserve_space(xdr, 4);
307	if (unlikely(hdr->status == NULL))
308		return htonl(NFS4ERR_RESOURCE);
309	status = encode_string(xdr, hdr->taglen, hdr->tag);
310	if (unlikely(status != 0))
311		return status;
312	hdr->nops = xdr_reserve_space(xdr, 4);
313	if (unlikely(hdr->nops == NULL))
314		return htonl(NFS4ERR_RESOURCE);
315	return 0;
316}
317
318static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
319{
320	__be32 *p;
321
322	p = xdr_reserve_space(xdr, 8);
323	if (unlikely(p == NULL))
324		return htonl(NFS4ERR_RESOURCE);
325	*p++ = htonl(op);
326	*p = res;
327	return 0;
328}
329
330static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
331{
332	__be32 *savep = NULL;
333	__be32 status = res->status;
334
335	if (unlikely(status != 0))
336		goto out;
337	status = encode_attr_bitmap(xdr, res->bitmap, &savep);
338	if (unlikely(status != 0))
339		goto out;
340	status = encode_attr_change(xdr, res->bitmap, res->change_attr);
341	if (unlikely(status != 0))
342		goto out;
343	status = encode_attr_size(xdr, res->bitmap, res->size);
344	if (unlikely(status != 0))
345		goto out;
346	status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
347	if (unlikely(status != 0))
348		goto out;
349	status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
350	*savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
351out:
352	dprintk("%s: exit with status = %d\n", __FUNCTION__, status);
353	return status;
354}
355
356static __be32 process_op(struct svc_rqst *rqstp,
357		struct xdr_stream *xdr_in, void *argp,
358		struct xdr_stream *xdr_out, void *resp)
359{
360	struct callback_op *op = &callback_ops[0];
361	unsigned int op_nr = OP_CB_ILLEGAL;
362	__be32 status = 0;
363	long maxlen;
364	__be32 res;
365
366	dprintk("%s: start\n", __FUNCTION__);
367	status = decode_op_hdr(xdr_in, &op_nr);
368	if (likely(status == 0)) {
369		switch (op_nr) {
370			case OP_CB_GETATTR:
371			case OP_CB_RECALL:
372				op = &callback_ops[op_nr];
373				break;
374			default:
375				op_nr = OP_CB_ILLEGAL;
376				op = &callback_ops[0];
377				status = htonl(NFS4ERR_OP_ILLEGAL);
378		}
379	}
380
381	maxlen = xdr_out->end - xdr_out->p;
382	if (maxlen > 0 && maxlen < PAGE_SIZE) {
383		if (likely(status == 0 && op->decode_args != NULL))
384			status = op->decode_args(rqstp, xdr_in, argp);
385		if (likely(status == 0 && op->process_op != NULL))
386			status = op->process_op(argp, resp);
387	} else
388		status = htonl(NFS4ERR_RESOURCE);
389
390	res = encode_op_hdr(xdr_out, op_nr, status);
391	if (status == 0)
392		status = res;
393	if (op->encode_res != NULL && status == 0)
394		status = op->encode_res(rqstp, xdr_out, resp);
395	dprintk("%s: done, status = %d\n", __FUNCTION__, status);
396	return status;
397}
398
399/*
400 * Decode, process and encode a COMPOUND
401 */
402static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
403{
404	struct cb_compound_hdr_arg hdr_arg;
405	struct cb_compound_hdr_res hdr_res;
406	struct xdr_stream xdr_in, xdr_out;
407	__be32 *p;
408	__be32 status;
409	unsigned int nops = 1;
410
411	dprintk("%s: start\n", __FUNCTION__);
412
413	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
414
415	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
416	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
417
418	decode_compound_hdr_arg(&xdr_in, &hdr_arg);
419	hdr_res.taglen = hdr_arg.taglen;
420	hdr_res.tag = hdr_arg.tag;
421	hdr_res.nops = NULL;
422	encode_compound_hdr_res(&xdr_out, &hdr_res);
423
424	for (;;) {
425		status = process_op(rqstp, &xdr_in, argp, &xdr_out, resp);
426		if (status != 0)
427			break;
428		if (nops == hdr_arg.nops)
429			break;
430		nops++;
431	}
432	*hdr_res.status = status;
433	*hdr_res.nops = htonl(nops);
434	dprintk("%s: done, status = %u\n", __FUNCTION__, status);
435	return rpc_success;
436}
437
438/*
439 * Define NFS4 callback COMPOUND ops.
440 */
441static struct callback_op callback_ops[] = {
442	[0] = {
443		.res_maxsize = CB_OP_HDR_RES_MAXSZ,
444	},
445	[OP_CB_GETATTR] = {
446		.process_op = (callback_process_op_t)nfs4_callback_getattr,
447		.decode_args = (callback_decode_arg_t)decode_getattr_args,
448		.encode_res = (callback_encode_res_t)encode_getattr_res,
449		.res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
450	},
451	[OP_CB_RECALL] = {
452		.process_op = (callback_process_op_t)nfs4_callback_recall,
453		.decode_args = (callback_decode_arg_t)decode_recall_args,
454		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
455	}
456};
457
458/*
459 * Define NFS4 callback procedures
460 */
461static struct svc_procedure nfs4_callback_procedures1[] = {
462	[CB_NULL] = {
463		.pc_func = nfs4_callback_null,
464		.pc_decode = (kxdrproc_t)nfs4_decode_void,
465		.pc_encode = (kxdrproc_t)nfs4_encode_void,
466		.pc_xdrressize = 1,
467	},
468	[CB_COMPOUND] = {
469		.pc_func = nfs4_callback_compound,
470		.pc_encode = (kxdrproc_t)nfs4_encode_void,
471		.pc_argsize = 256,
472		.pc_ressize = 256,
473		.pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
474	}
475};
476
477struct svc_version nfs4_callback_version1 = {
478	.vs_vers = 1,
479	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
480	.vs_proc = nfs4_callback_procedures1,
481	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
482	.vs_dispatch = NULL,
483};
484