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/config.h>
   9 #include <linux/kernel.h>
  10 #include <linux/sunrpc/svc.h>
  11 #include <linux/nfs4.h>
  12 #include <linux/nfs_fs.h>
  13 #include "nfs4_fs.h"
  14 #include "callback.h"
  15
  16 #define CB_OP_TAGLEN_MAXSZ      (512)
  17 #define CB_OP_HDR_RES_MAXSZ     (2 + CB_OP_TAGLEN_MAXSZ)
  18 #define CB_OP_GETATTR_BITMAP_MAXSZ      (4)
  19 #define CB_OP_GETATTR_RES_MAXSZ (CB_OP_HDR_RES_MAXSZ + \
  20                                 CB_OP_GETATTR_BITMAP_MAXSZ + \
  21                                 2 + 2 + 3 + 3)
  22 #define CB_OP_RECALL_RES_MAXSZ  (CB_OP_HDR_RES_MAXSZ)
  23
  24 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  25
  26 typedef unsigned (*callback_process_op_t)(void *, void *);
  27 typedef unsigned (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
  28 typedef unsigned (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
  29
  30
  31 struct callback_op {
  32         callback_process_op_t process_op;
  33         callback_decode_arg_t decode_args;
  34         callback_encode_res_t encode_res;
  35         long res_maxsize;
  36 };
  37
  38 static struct callback_op callback_ops[];
  39
  40 static int nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
  41 {
  42         return htonl(NFS4_OK);
  43 }
  44
  45 static int nfs4_decode_void(struct svc_rqst *rqstp, uint32_t *p, void *dummy)
  46 {
  47         return xdr_argsize_check(rqstp, p);
  48 }
  49
  50 static int nfs4_encode_void(struct svc_rqst *rqstp, uint32_t *p, void *dummy)
  51 {
  52         return xdr_ressize_check(rqstp, p);
  53 }
  54
  55 static uint32_t *read_buf(struct xdr_stream *xdr, int nbytes)
  56 {
  57         uint32_t *p;
  58
  59         p = xdr_inline_decode(xdr, nbytes);
  60         if (unlikely(p == NULL))
  61                 printk(KERN_WARNING "NFSv4 callback reply buffer overflowed!\n");
  62         return p;
  63 }
  64
  65 static unsigned decode_string(struct xdr_stream *xdr, unsigned int *len, const char **str)
  66 {
  67         uint32_t *p;
  68
  69         p = read_buf(xdr, 4);
  70         if (unlikely(p == NULL))
  71                 return htonl(NFS4ERR_RESOURCE);
  72         *len = ntohl(*p);
  73
  74         if (*len != 0) {
  75                 p = read_buf(xdr, *len);
  76                 if (unlikely(p == NULL))
  77                         return htonl(NFS4ERR_RESOURCE);
  78                 *str = (const char *)p;
  79         } else
  80                 *str = NULL;
  81
  82         return 0;
  83 }
  84
  85 static unsigned decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
  86 {
  87         uint32_t *p;
  88
  89         p = read_buf(xdr, 4);
  90         if (unlikely(p == NULL))
  91                 return htonl(NFS4ERR_RESOURCE);
  92         fh->size = ntohl(*p);
  93         if (fh->size > NFS4_FHSIZE)
  94                 return htonl(NFS4ERR_BADHANDLE);
  95         p = read_buf(xdr, fh->size);
  96         if (unlikely(p == NULL))
  97                 return htonl(NFS4ERR_RESOURCE);
  98         memcpy(&fh->data[0], p, fh->size);
  99         memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
 100         return 0;
 101 }
 102
 103 static unsigned decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
 104 {
 105         uint32_t *p;
 106         unsigned int attrlen;
 107
 108         p = read_buf(xdr, 4);
 109         if (unlikely(p == NULL))
 110                 return htonl(NFS4ERR_RESOURCE);
 111         attrlen = ntohl(*p);
 112         p = read_buf(xdr, attrlen << 2);
 113         if (unlikely(p == NULL))
 114                 return htonl(NFS4ERR_RESOURCE);
 115         if (likely(attrlen > 0))
 116                 bitmap[0] = ntohl(*p++);
 117         if (attrlen > 1)
 118                 bitmap[1] = ntohl(*p);
 119         return 0;
 120 }
 121
 122 static unsigned decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
 123 {
 124         uint32_t *p;
 125
 126         p = read_buf(xdr, 16);
 127         if (unlikely(p == NULL))
 128                 return htonl(NFS4ERR_RESOURCE);
 129         memcpy(stateid->data, p, 16);
 130         return 0;
 131 }
 132
 133 static unsigned decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
 134 {
 135         uint32_t *p;
 136         unsigned int minor_version;
 137         unsigned status;
 138
 139         status = decode_string(xdr, &hdr->taglen, &hdr->tag);
 140         if (unlikely(status != 0))
 141                 return status;
 142         /* We do not like overly long tags! */
 143         if (hdr->taglen > CB_OP_TAGLEN_MAXSZ-12 || hdr->taglen < 0) {
 144                 printk("NFSv4 CALLBACK %s: client sent tag of length %u\n",
 145                                 __FUNCTION__, hdr->taglen);
 146                 return htonl(NFS4ERR_RESOURCE);
 147         }
 148         p = read_buf(xdr, 12);
 149         if (unlikely(p == NULL))
 150                 return htonl(NFS4ERR_RESOURCE);
 151         minor_version = ntohl(*p++);
 152         /* Check minor version is zero. */
 153         if (minor_version != 0) {
 154                 printk(KERN_WARNING "%s: NFSv4 server callback with illegal minor version %u!\n",
 155                                 __FUNCTION__, minor_version);
 156                 return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
 157         }
 158         hdr->callback_ident = ntohl(*p++);
 159         hdr->nops = ntohl(*p);
 160         return 0;
 161 }
 162
 163 static unsigned decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
 164 {
 165         uint32_t *p;
 166         p = read_buf(xdr, 4);
 167         if (unlikely(p == NULL))
 168                 return htonl(NFS4ERR_RESOURCE);
 169         *op = ntohl(*p);
 170         return 0;
 171 }
 172
 173 static unsigned decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
 174 {
 175         unsigned status;
 176
 177         status = decode_fh(xdr, &args->fh);
 178         if (unlikely(status != 0))
 179                 goto out;
 180         args->addr = &rqstp->rq_addr;
 181         status = decode_bitmap(xdr, args->bitmap);
 182 out:
 183         dprintk("%s: exit with status = %d\n", __FUNCTION__, status);
 184         return status;
 185 }
 186
 187 static unsigned decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
 188 {
 189         uint32_t *p;
 190         unsigned status;
 191
 192         args->addr = &rqstp->rq_addr;
 193         status = decode_stateid(xdr, &args->stateid);
 194         if (unlikely(status != 0))
 195                 goto out;
 196         p = read_buf(xdr, 4);
 197         if (unlikely(p == NULL)) {
 198                 status = htonl(NFS4ERR_RESOURCE);
 199                 goto out;
 200         }
 201         args->truncate = ntohl(*p);
 202         status = decode_fh(xdr, &args->fh);
 203 out:
 204         dprintk("%s: exit with status = %d\n", __FUNCTION__, status);
 205         return 0;
 206 }
 207
 208 static unsigned encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
 209 {
 210         uint32_t *p;
 211
 212         p = xdr_reserve_space(xdr, 4 + len);
 213         if (unlikely(p == NULL))
 214                 return htonl(NFS4ERR_RESOURCE);
 215         xdr_encode_opaque(p, str, len);
 216         return 0;
 217 }
 218
 219 #define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
 220 #define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
 221 static unsigned encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, uint32_t **savep)
 222 {
 223         uint32_t bm[2];
 224         uint32_t *p;
 225
 226         bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
 227         bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
 228         if (bm[1] != 0) {
 229                 p = xdr_reserve_space(xdr, 16);
 230                 if (unlikely(p == NULL))
 231                         return htonl(NFS4ERR_RESOURCE);
 232                 *p++ = htonl(2);
 233                 *p++ = bm[0];
 234                 *p++ = bm[1];
 235         } else if (bm[0] != 0) {
 236                 p = xdr_reserve_space(xdr, 12);
 237                 if (unlikely(p == NULL))
 238                         return htonl(NFS4ERR_RESOURCE);
 239                 *p++ = htonl(1);
 240                 *p++ = bm[0];
 241         } else {
 242                 p = xdr_reserve_space(xdr, 8);
 243                 if (unlikely(p == NULL))
 244                         return htonl(NFS4ERR_RESOURCE);
 245                 *p++ = htonl(0);
 246         }
 247         *savep = p;
 248         return 0;
 249 }
 250
 251 static unsigned encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
 252 {
 253         uint32_t *p;
 254
 255         if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
 256                 return 0;
 257         p = xdr_reserve_space(xdr, 8);
 258         if (unlikely(p == 0))
 259                 return htonl(NFS4ERR_RESOURCE);
 260         p = xdr_encode_hyper(p, change);
 261         return 0;
 262 }
 263
 264 static unsigned encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
 265 {
 266         uint32_t *p;
 267
 268         if (!(bitmap[0] & FATTR4_WORD0_SIZE))
 269                 return 0;
 270         p = xdr_reserve_space(xdr, 8);
 271         if (unlikely(p == 0))
 272                 return htonl(NFS4ERR_RESOURCE);
 273         p = xdr_encode_hyper(p, size);
 274         return 0;
 275 }
 276
 277 static unsigned encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
 278 {
 279         uint32_t *p;
 280
 281         p = xdr_reserve_space(xdr, 12);
 282         if (unlikely(p == 0))
 283                 return htonl(NFS4ERR_RESOURCE);
 284         p = xdr_encode_hyper(p, time->tv_sec);
 285         *p = htonl(time->tv_nsec);
 286         return 0;
 287 }
 288
 289 static unsigned encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
 290 {
 291         if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
 292                 return 0;
 293         return encode_attr_time(xdr,time);
 294 }
 295
 296 static unsigned encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
 297 {
 298         if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
 299                 return 0;
 300         return encode_attr_time(xdr,time);
 301 }
 302
 303 static unsigned encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
 304 {
 305         unsigned status;
 306
 307         hdr->status = xdr_reserve_space(xdr, 4);
 308         if (unlikely(hdr->status == NULL))
 309                 return htonl(NFS4ERR_RESOURCE);
 310         status = encode_string(xdr, hdr->taglen, hdr->tag);
 311         if (unlikely(status != 0))
 312                 return status;
 313         hdr->nops = xdr_reserve_space(xdr, 4);
 314         if (unlikely(hdr->nops == NULL))
 315                 return htonl(NFS4ERR_RESOURCE);
 316         return 0;
 317 }
 318
 319 static unsigned encode_op_hdr(struct xdr_stream *xdr, uint32_t op, uint32_t res)
 320 {
 321         uint32_t *p;
 322
 323         p = xdr_reserve_space(xdr, 8);
 324         if (unlikely(p == NULL))
 325                 return htonl(NFS4ERR_RESOURCE);
 326         *p++ = htonl(op);
 327         *p = res;
 328         return 0;
 329 }
 330
 331 static unsigned encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
 332 {
 333         uint32_t *savep = NULL;
 334         unsigned status = res->status;
 335
 336         if (unlikely(status != 0))
 337                 goto out;
 338         status = encode_attr_bitmap(xdr, res->bitmap, &savep);
 339         if (unlikely(status != 0))
 340                 goto out;
 341         status = encode_attr_change(xdr, res->bitmap, res->change_attr);
 342         if (unlikely(status != 0))
 343                 goto out;
 344         status = encode_attr_size(xdr, res->bitmap, res->size);
 345         if (unlikely(status != 0))
 346                 goto out;
 347         status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
 348         if (unlikely(status != 0))
 349                 goto out;
 350         status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
 351         *savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
 352 out:
 353         dprintk("%s: exit with status = %d\n", __FUNCTION__, status);
 354         return status;
 355 }
 356
 357 static unsigned process_op(struct svc_rqst *rqstp,
 358                 struct xdr_stream *xdr_in, void *argp,
 359                 struct xdr_stream *xdr_out, void *resp)
 360 {
 361         struct callback_op *op = &callback_ops[0];
 362         unsigned int op_nr = OP_CB_ILLEGAL;
 363         unsigned int status = 0;
 364         long maxlen;
 365         unsigned res;
 366
 367         dprintk("%s: start\n", __FUNCTION__);
 368         status = decode_op_hdr(xdr_in, &op_nr);
 369         if (likely(status == 0)) {
 370                 switch (op_nr) {
 371                         case OP_CB_GETATTR:
 372                         case OP_CB_RECALL:
 373                                 op = &callback_ops[op_nr];
 374                                 break;
 375                         default:
 376                                 op_nr = OP_CB_ILLEGAL;
 377                                 op = &callback_ops[0];
 378                                 status = htonl(NFS4ERR_OP_ILLEGAL);
 379                 }
 380         }
 381
 382         maxlen = xdr_out->end - xdr_out->p;
 383         if (maxlen > 0 && maxlen < PAGE_SIZE) {
 384                 if (likely(status == 0 && op->decode_args != NULL))
 385                         status = op->decode_args(rqstp, xdr_in, argp);
 386                 if (likely(status == 0 && op->process_op != NULL))
 387                         status = op->process_op(argp, resp);
 388         } else
 389                 status = htonl(NFS4ERR_RESOURCE);
 390
 391         res = encode_op_hdr(xdr_out, op_nr, status);
 392         if (status == 0)
 393                 status = res;
 394         if (op->encode_res != NULL && status == 0)
 395                 status = op->encode_res(rqstp, xdr_out, resp);
 396         dprintk("%s: done, status = %d\n", __FUNCTION__, status);
 397         return status;
 398 }
 399
 400 /*
 401  * Decode, process and encode a COMPOUND
 402  */
 403 static int nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
 404 {
 405         struct cb_compound_hdr_arg hdr_arg;
 406         struct cb_compound_hdr_res hdr_res;
 407         struct xdr_stream xdr_in, xdr_out;
 408         uint32_t *p;
 409         unsigned int status;
 410         unsigned int nops = 1;
 411
 412         dprintk("%s: start\n", __FUNCTION__);
 413
 414         xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
 415
 416         p = (uint32_t*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
 417         xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
 418
 419         decode_compound_hdr_arg(&xdr_in, &hdr_arg);
 420         hdr_res.taglen = hdr_arg.taglen;
 421         hdr_res.tag = hdr_arg.tag;
 422         hdr_res.nops = NULL;
 423         encode_compound_hdr_res(&xdr_out, &hdr_res);
 424
 425         for (;;) {
 426                 status = process_op(rqstp, &xdr_in, argp, &xdr_out, resp);
 427                 if (status != 0)
 428                         break;
 429                 if (nops == hdr_arg.nops)
 430                         break;
 431                 nops++;
 432         }
 433         *hdr_res.status = status;
 434         *hdr_res.nops = htonl(nops);
 435         dprintk("%s: done, status = %u\n", __FUNCTION__, status);
 436         return rpc_success;
 437 }
 438
 439 /*
 440  * Define NFS4 callback COMPOUND ops.
 441  */
 442 static struct callback_op callback_ops[] = {
 443         [0] = {
 444                 .res_maxsize = CB_OP_HDR_RES_MAXSZ,
 445         },
 446         [OP_CB_GETATTR] = {
 447                 .process_op = (callback_process_op_t)nfs4_callback_getattr,
 448                 .decode_args = (callback_decode_arg_t)decode_getattr_args,
 449                 .encode_res = (callback_encode_res_t)encode_getattr_res,
 450                 .res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
 451         },
 452         [OP_CB_RECALL] = {
 453                 .process_op = (callback_process_op_t)nfs4_callback_recall,
 454                 .decode_args = (callback_decode_arg_t)decode_recall_args,
 455                 .res_maxsize = CB_OP_RECALL_RES_MAXSZ,
 456         }
 457 };
 458
 459 /*
 460  * Define NFS4 callback procedures
 461  */
 462 static struct svc_procedure nfs4_callback_procedures1[] = {
 463         [CB_NULL] = {
 464                 .pc_func = nfs4_callback_null,
 465                 .pc_decode = (kxdrproc_t)nfs4_decode_void,
 466                 .pc_encode = (kxdrproc_t)nfs4_encode_void,
 467                 .pc_xdrressize = 1,
 468         },
 469         [CB_COMPOUND] = {
 470                 .pc_func = nfs4_callback_compound,
 471                 .pc_encode = (kxdrproc_t)nfs4_encode_void,
 472                 .pc_argsize = 256,
 473                 .pc_ressize = 256,
 474                 .pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
 475         }
 476 };
 477
 478 struct svc_version nfs4_callback_version1 = {
 479         .vs_vers = 1,
 480         .vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
 481         .vs_proc = nfs4_callback_procedures1,
 482         .vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
 483         .vs_dispatch = NULL,
 484 };
 485