fs/nfs/callback_xdr.c

   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
  25 typedef __be32 (*callback_process_op_t)(void *, void *);
  26 typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
  27 typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
  28
  29
  30 struct 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
  37 static struct callback_op callback_ops[];
  38
  39 static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
  40 {
  41         return htonl(NFS4_OK);
  42 }
  43
  44 static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
  45 {
  46         return xdr_argsize_check(rqstp, p);
  47 }
  48
  49 static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
  50 {
  51         return xdr_ressize_check(rqstp, p);
  52 }
  53
  54 static __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
  64 static __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
  84 static __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
 102 static __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
 121 static __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
 132 static __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) {
 143                 printk("NFSv4 CALLBACK %s: client sent tag of length %u\n",
 144                                 __func__, 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                                 __func__, 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
 162 static __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
 172 static __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(rqstp);
 180         status = decode_bitmap(xdr, args->bitmap);
 181 out:
 182         dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
 183         return status;
 184 }
 185
 186 static __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(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);
 202 out:
 203         dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
 204         return status;
 205 }
 206
 207 static __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)
 220 static __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
 250 static __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))
 258                 return htonl(NFS4ERR_RESOURCE);
 259         p = xdr_encode_hyper(p, change);
 260         return 0;
 261 }
 262
 263 static __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))
 271                 return htonl(NFS4ERR_RESOURCE);
 272         p = xdr_encode_hyper(p, size);
 273         return 0;
 274 }
 275
 276 static __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))
 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
 288 static __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
 295 static __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
 302 static __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
 318 static __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
 330 static __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)));
 351 out:
 352         dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
 353         return status;
 354 }
 355
 356 static __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", __func__);
 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", __func__, ntohl(status));
 396         return status;
 397 }
 398
 399 /*
 400  * Decode, process and encode a COMPOUND
 401  */
 402 static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
 403 {
 404         struct cb_compound_hdr_arg hdr_arg = { 0 };
 405         struct cb_compound_hdr_res hdr_res = { NULL };
 406         struct xdr_stream xdr_in, xdr_out;
 407         __be32 *p;
 408         __be32 status;
 409         unsigned int nops = 0;
 410
 411         dprintk("%s: start\n", __func__);
 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         status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
 419         if (status == __constant_htonl(NFS4ERR_RESOURCE))
 420                 return rpc_garbage_args;
 421
 422         hdr_res.taglen = hdr_arg.taglen;
 423         hdr_res.tag = hdr_arg.tag;
 424         if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
 425                 return rpc_system_err;
 426
 427         while (status == 0 && nops != hdr_arg.nops) {
 428                 status = process_op(rqstp, &xdr_in, argp, &xdr_out, resp);
 429                 nops++;
 430         }
 431
 432         *hdr_res.status = status;
 433         *hdr_res.nops = htonl(nops);
 434         dprintk("%s: done, status = %u\n", __func__, ntohl(status));
 435         return rpc_success;
 436 }
 437
 438 /*
 439  * Define NFS4 callback COMPOUND ops.
 440  */
 441 static 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  */
 461 static 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
 477 struct 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