1 /* $NetBSD: xdr.c,v 1.22 2000/07/06 03:10:35 christos Exp $ */ 2 3 /* 4 * Sun RPC is a product of Sun Microsystems, Inc. and is provided for 5 * unrestricted use provided that this legend is included on all tape 6 * media and as a part of the software program in whole or part. Users 7 * may copy or modify Sun RPC without charge, but are not authorized 8 * to license or distribute it to anyone else except as part of a product or 9 * program developed by the user. 10 * 11 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE 12 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR 13 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE. 14 * 15 * Sun RPC is provided with no support and without any obligation on the 16 * part of Sun Microsystems, Inc. to assist in its use, correction, 17 * modification or enhancement. 18 * 19 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE 20 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC 21 * OR ANY PART THEREOF. 22 * 23 * In no event will Sun Microsystems, Inc. be liable for any lost revenue 24 * or profits or other special, indirect and consequential damages, even if 25 * Sun has been advised of the possibility of such damages. 26 * 27 * Sun Microsystems, Inc. 28 * 2550 Garcia Avenue 29 * Mountain View, California 94043 30 */ 31 32 #include <sys/cdefs.h> 33 /* 34 * xdr.c, Generic XDR routines implementation. 35 * 36 * Copyright (C) 1986, Sun Microsystems, Inc. 37 * 38 * These are the "generic" xdr routines used to serialize and de-serialize 39 * most common data items. See xdr.h for more info on the interface to 40 * xdr. 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/kernel.h> 46 #include <sys/malloc.h> 47 #include <sys/module.h> 48 49 #include <rpc/rpc.h> 50 #include <rpc/rpc_com.h> 51 #include <rpc/types.h> 52 #include <rpc/xdr.h> 53 54 typedef quad_t longlong_t; /* ANSI long long type */ 55 typedef u_quad_t u_longlong_t; /* ANSI unsigned long long type */ 56 57 /* 58 * constants specific to the xdr "protocol" 59 */ 60 #define XDR_FALSE ((long) 0) 61 #define XDR_TRUE ((long) 1) 62 63 MALLOC_DEFINE(M_RPC, "rpc", "Remote Procedure Call"); 64 65 /* 66 * for unit alignment 67 */ 68 static const char xdr_zero[BYTES_PER_XDR_UNIT] = { 0, 0, 0, 0 }; 69 70 /* 71 * Free a data structure using XDR 72 * Not a filter, but a convenient utility nonetheless 73 */ 74 void 75 xdr_free(xdrproc_t proc, void *objp) 76 { 77 XDR x; 78 79 x.x_op = XDR_FREE; 80 (*proc)(&x, objp); 81 } 82 83 /* 84 * XDR nothing 85 */ 86 bool_t 87 xdr_void(XDR *xrds __unused, void *ptr __unused) 88 { 89 return (TRUE); 90 } 91 92 /* 93 * XDR integers 94 */ 95 bool_t 96 xdr_int(XDR *xdrs, int *ip) 97 { 98 long l; 99 100 switch (xdrs->x_op) { 101 case XDR_ENCODE: 102 l = (long) *ip; 103 return (XDR_PUTLONG(xdrs, &l)); 104 105 case XDR_DECODE: 106 if (!XDR_GETLONG(xdrs, &l)) { 107 return (FALSE); 108 } 109 *ip = (int) l; 110 return (TRUE); 111 112 case XDR_FREE: 113 return (TRUE); 114 } 115 /* NOTREACHED */ 116 return (FALSE); 117 } 118 119 /* 120 * XDR unsigned integers 121 */ 122 bool_t 123 xdr_u_int(XDR *xdrs, u_int *up) 124 { 125 u_long l; 126 127 switch (xdrs->x_op) { 128 case XDR_ENCODE: 129 l = (u_long) *up; 130 return (XDR_PUTLONG(xdrs, (long *)&l)); 131 132 case XDR_DECODE: 133 if (!XDR_GETLONG(xdrs, (long *)&l)) { 134 return (FALSE); 135 } 136 *up = (u_int) l; 137 return (TRUE); 138 139 case XDR_FREE: 140 return (TRUE); 141 } 142 /* NOTREACHED */ 143 return (FALSE); 144 } 145 146 /* 147 * XDR long integers 148 * same as xdr_u_long - open coded to save a proc call! 149 */ 150 bool_t 151 xdr_long(XDR *xdrs, long *lp) 152 { 153 switch (xdrs->x_op) { 154 case XDR_ENCODE: 155 return (XDR_PUTLONG(xdrs, lp)); 156 case XDR_DECODE: 157 return (XDR_GETLONG(xdrs, lp)); 158 case XDR_FREE: 159 return (TRUE); 160 } 161 /* NOTREACHED */ 162 return (FALSE); 163 } 164 165 /* 166 * XDR unsigned long integers 167 * same as xdr_long - open coded to save a proc call! 168 */ 169 bool_t 170 xdr_u_long(XDR *xdrs, u_long *ulp) 171 { 172 switch (xdrs->x_op) { 173 case XDR_ENCODE: 174 return (XDR_PUTLONG(xdrs, (long *)ulp)); 175 case XDR_DECODE: 176 return (XDR_GETLONG(xdrs, (long *)ulp)); 177 case XDR_FREE: 178 return (TRUE); 179 } 180 /* NOTREACHED */ 181 return (FALSE); 182 } 183 184 /* 185 * XDR 32-bit integers 186 * same as xdr_uint32_t - open coded to save a proc call! 187 */ 188 bool_t 189 xdr_int32_t(XDR *xdrs, int32_t *int32_p) 190 { 191 long l; 192 193 switch (xdrs->x_op) { 194 case XDR_ENCODE: 195 l = (long) *int32_p; 196 return (XDR_PUTLONG(xdrs, &l)); 197 198 case XDR_DECODE: 199 if (!XDR_GETLONG(xdrs, &l)) { 200 return (FALSE); 201 } 202 *int32_p = (int32_t) l; 203 return (TRUE); 204 205 case XDR_FREE: 206 return (TRUE); 207 } 208 /* NOTREACHED */ 209 return (FALSE); 210 } 211 212 /* 213 * XDR unsigned 32-bit integers 214 * same as xdr_int32_t - open coded to save a proc call! 215 */ 216 bool_t 217 xdr_uint32_t(XDR *xdrs, uint32_t *uint32_p) 218 { 219 u_long l; 220 221 switch (xdrs->x_op) { 222 case XDR_ENCODE: 223 l = (u_long) *uint32_p; 224 return (XDR_PUTLONG(xdrs, (long *)&l)); 225 226 case XDR_DECODE: 227 if (!XDR_GETLONG(xdrs, (long *)&l)) { 228 return (FALSE); 229 } 230 *uint32_p = (uint32_t) l; 231 return (TRUE); 232 233 case XDR_FREE: 234 return (TRUE); 235 } 236 /* NOTREACHED */ 237 return (FALSE); 238 } 239 240 /* 241 * XDR short integers 242 */ 243 bool_t 244 xdr_short(XDR *xdrs, short *sp) 245 { 246 long l; 247 248 switch (xdrs->x_op) { 249 case XDR_ENCODE: 250 l = (long) *sp; 251 return (XDR_PUTLONG(xdrs, &l)); 252 253 case XDR_DECODE: 254 if (!XDR_GETLONG(xdrs, &l)) { 255 return (FALSE); 256 } 257 *sp = (short) l; 258 return (TRUE); 259 260 case XDR_FREE: 261 return (TRUE); 262 } 263 /* NOTREACHED */ 264 return (FALSE); 265 } 266 267 /* 268 * XDR unsigned short integers 269 */ 270 bool_t 271 xdr_u_short(XDR *xdrs, u_short *usp) 272 { 273 u_long l; 274 275 switch (xdrs->x_op) { 276 case XDR_ENCODE: 277 l = (u_long) *usp; 278 return (XDR_PUTLONG(xdrs, (long *)&l)); 279 280 case XDR_DECODE: 281 if (!XDR_GETLONG(xdrs, (long *)&l)) { 282 return (FALSE); 283 } 284 *usp = (u_short) l; 285 return (TRUE); 286 287 case XDR_FREE: 288 return (TRUE); 289 } 290 /* NOTREACHED */ 291 return (FALSE); 292 } 293 294 /* 295 * XDR 16-bit integers 296 */ 297 bool_t 298 xdr_int16_t(XDR *xdrs, int16_t *int16_p) 299 { 300 long l; 301 302 switch (xdrs->x_op) { 303 case XDR_ENCODE: 304 l = (long) *int16_p; 305 return (XDR_PUTLONG(xdrs, &l)); 306 307 case XDR_DECODE: 308 if (!XDR_GETLONG(xdrs, &l)) { 309 return (FALSE); 310 } 311 *int16_p = (int16_t) l; 312 return (TRUE); 313 314 case XDR_FREE: 315 return (TRUE); 316 } 317 /* NOTREACHED */ 318 return (FALSE); 319 } 320 321 /* 322 * XDR unsigned 16-bit integers 323 */ 324 bool_t 325 xdr_uint16_t(XDR *xdrs, uint16_t *uint16_p) 326 { 327 u_long l; 328 329 switch (xdrs->x_op) { 330 case XDR_ENCODE: 331 l = (u_long) *uint16_p; 332 return (XDR_PUTLONG(xdrs, (long *)&l)); 333 334 case XDR_DECODE: 335 if (!XDR_GETLONG(xdrs, (long *)&l)) { 336 return (FALSE); 337 } 338 *uint16_p = (uint16_t) l; 339 return (TRUE); 340 341 case XDR_FREE: 342 return (TRUE); 343 } 344 /* NOTREACHED */ 345 return (FALSE); 346 } 347 348 /* 349 * XDR a char 350 */ 351 bool_t 352 xdr_char(XDR *xdrs, char *cp) 353 { 354 u_int i; 355 356 i = *((unsigned char *)cp); 357 if (!xdr_u_int(xdrs, &i)) { 358 return (FALSE); 359 } 360 *((unsigned char *)cp) = i; 361 return (TRUE); 362 } 363 364 /* 365 * XDR an unsigned char 366 */ 367 bool_t 368 xdr_u_char(XDR *xdrs, u_char *cp) 369 { 370 u_int u; 371 372 u = (*cp); 373 if (!xdr_u_int(xdrs, &u)) { 374 return (FALSE); 375 } 376 *cp = u; 377 return (TRUE); 378 } 379 380 /* 381 * XDR booleans 382 */ 383 bool_t 384 xdr_bool(XDR *xdrs, bool_t *bp) 385 { 386 long lb; 387 388 switch (xdrs->x_op) { 389 case XDR_ENCODE: 390 lb = *bp ? XDR_TRUE : XDR_FALSE; 391 return (XDR_PUTLONG(xdrs, &lb)); 392 393 case XDR_DECODE: 394 if (!XDR_GETLONG(xdrs, &lb)) { 395 return (FALSE); 396 } 397 *bp = (lb == XDR_FALSE) ? FALSE : TRUE; 398 return (TRUE); 399 400 case XDR_FREE: 401 return (TRUE); 402 } 403 /* NOTREACHED */ 404 return (FALSE); 405 } 406 407 /* 408 * XDR enumerations 409 */ 410 bool_t 411 xdr_enum(XDR *xdrs, enum_t *ep) 412 { 413 enum sizecheck { SIZEVAL }; /* used to find the size of an enum */ 414 415 /* 416 * enums are treated as ints 417 */ 418 /* LINTED */ if (sizeof (enum sizecheck) == sizeof (long)) { 419 return (xdr_long(xdrs, (long *)(void *)ep)); 420 } else /* LINTED */ if (sizeof (enum sizecheck) == sizeof (int)) { 421 return (xdr_int(xdrs, (int *)(void *)ep)); 422 } else /* LINTED */ if (sizeof (enum sizecheck) == sizeof (short)) { 423 return (xdr_short(xdrs, (short *)(void *)ep)); 424 } else { 425 return (FALSE); 426 } 427 } 428 429 /* 430 * XDR opaque data 431 * Allows the specification of a fixed size sequence of opaque bytes. 432 * cp points to the opaque object and cnt gives the byte length. 433 */ 434 bool_t 435 xdr_opaque(XDR *xdrs, caddr_t cp, u_int cnt) 436 { 437 u_int rndup; 438 static int crud[BYTES_PER_XDR_UNIT]; 439 440 /* 441 * if no data we are done 442 */ 443 if (cnt == 0) 444 return (TRUE); 445 446 /* 447 * round byte count to full xdr units 448 */ 449 rndup = cnt % BYTES_PER_XDR_UNIT; 450 if (rndup > 0) 451 rndup = BYTES_PER_XDR_UNIT - rndup; 452 453 if (xdrs->x_op == XDR_DECODE) { 454 if (!XDR_GETBYTES(xdrs, cp, cnt)) { 455 return (FALSE); 456 } 457 if (rndup == 0) 458 return (TRUE); 459 return (XDR_GETBYTES(xdrs, (caddr_t)(void *)crud, rndup)); 460 } 461 462 if (xdrs->x_op == XDR_ENCODE) { 463 if (!XDR_PUTBYTES(xdrs, cp, cnt)) { 464 return (FALSE); 465 } 466 if (rndup == 0) 467 return (TRUE); 468 return (XDR_PUTBYTES(xdrs, xdr_zero, rndup)); 469 } 470 471 if (xdrs->x_op == XDR_FREE) { 472 return (TRUE); 473 } 474 475 return (FALSE); 476 } 477 478 /* 479 * XDR counted bytes 480 * *cpp is a pointer to the bytes, *sizep is the count. 481 * If *cpp is NULL maxsize bytes are allocated 482 */ 483 bool_t 484 xdr_bytes(XDR *xdrs, char **cpp, u_int *sizep, u_int maxsize) 485 { 486 char *sp = *cpp; /* sp is the actual string pointer */ 487 u_int nodesize; 488 bool_t ret, allocated = FALSE; 489 490 /* 491 * first deal with the length since xdr bytes are counted 492 */ 493 if (! xdr_u_int(xdrs, sizep)) { 494 return (FALSE); 495 } 496 nodesize = *sizep; 497 if ((nodesize > maxsize) && (xdrs->x_op != XDR_FREE)) { 498 return (FALSE); 499 } 500 501 /* 502 * now deal with the actual bytes 503 */ 504 switch (xdrs->x_op) { 505 case XDR_DECODE: 506 if (nodesize == 0) { 507 return (TRUE); 508 } 509 if (sp == NULL) { 510 *cpp = sp = mem_alloc(nodesize); 511 allocated = TRUE; 512 } 513 if (sp == NULL) { 514 printf("xdr_bytes: out of memory"); 515 return (FALSE); 516 } 517 /* FALLTHROUGH */ 518 519 case XDR_ENCODE: 520 ret = xdr_opaque(xdrs, sp, nodesize); 521 if ((xdrs->x_op == XDR_DECODE) && (ret == FALSE)) { 522 if (allocated == TRUE) { 523 mem_free(sp, nodesize); 524 *cpp = NULL; 525 } 526 } 527 return (ret); 528 529 case XDR_FREE: 530 if (sp != NULL) { 531 mem_free(sp, nodesize); 532 *cpp = NULL; 533 } 534 return (TRUE); 535 } 536 /* NOTREACHED */ 537 return (FALSE); 538 } 539 540 /* 541 * Implemented here due to commonality of the object. 542 */ 543 bool_t 544 xdr_netobj(XDR *xdrs, struct netobj *np) 545 { 546 547 return (xdr_bytes(xdrs, &np->n_bytes, &np->n_len, MAX_NETOBJ_SZ)); 548 } 549 550 /* 551 * XDR a descriminated union 552 * Support routine for discriminated unions. 553 * You create an array of xdrdiscrim structures, terminated with 554 * an entry with a null procedure pointer. The routine gets 555 * the discriminant value and then searches the array of xdrdiscrims 556 * looking for that value. It calls the procedure given in the xdrdiscrim 557 * to handle the discriminant. If there is no specific routine a default 558 * routine may be called. 559 * If there is no specific or default routine an error is returned. 560 */ 561 bool_t 562 xdr_union(XDR *xdrs, 563 enum_t *dscmp, /* enum to decide which arm to work on */ 564 char *unp, /* the union itself */ 565 const struct xdr_discrim *choices, /* [value, xdr proc] for each arm */ 566 xdrproc_t dfault) /* default xdr routine */ 567 { 568 enum_t dscm; 569 570 /* 571 * we deal with the discriminator; it's an enum 572 */ 573 if (! xdr_enum(xdrs, dscmp)) { 574 return (FALSE); 575 } 576 dscm = *dscmp; 577 578 /* 579 * search choices for a value that matches the discriminator. 580 * if we find one, execute the xdr routine for that value. 581 */ 582 for (; choices->proc != NULL_xdrproc_t; choices++) { 583 if (choices->value == dscm) 584 return ((*(choices->proc))(xdrs, unp)); 585 } 586 587 /* 588 * no match - execute the default xdr routine if there is one 589 */ 590 return ((dfault == NULL_xdrproc_t) ? FALSE : 591 (*dfault)(xdrs, unp)); 592 } 593 594 /* 595 * Non-portable xdr primitives. 596 * Care should be taken when moving these routines to new architectures. 597 */ 598 599 /* 600 * XDR null terminated ASCII strings 601 * xdr_string deals with "C strings" - arrays of bytes that are 602 * terminated by a NULL character. The parameter cpp references a 603 * pointer to storage; If the pointer is null, then the necessary 604 * storage is allocated. The last parameter is the max allowed length 605 * of the string as specified by a protocol. 606 */ 607 bool_t 608 xdr_string(XDR *xdrs, char **cpp, u_int maxsize) 609 { 610 char *sp = *cpp; /* sp is the actual string pointer */ 611 u_int size; 612 u_int nodesize; 613 bool_t ret, allocated = FALSE; 614 615 /* 616 * first deal with the length since xdr strings are counted-strings 617 */ 618 switch (xdrs->x_op) { 619 case XDR_FREE: 620 if (sp == NULL) { 621 return(TRUE); /* already free */ 622 } 623 /* FALLTHROUGH */ 624 case XDR_ENCODE: 625 size = strlen(sp); 626 break; 627 case XDR_DECODE: 628 break; 629 } 630 if (! xdr_u_int(xdrs, &size)) { 631 return (FALSE); 632 } 633 if (size > maxsize) { 634 return (FALSE); 635 } 636 nodesize = size + 1; 637 638 /* 639 * now deal with the actual bytes 640 */ 641 switch (xdrs->x_op) { 642 case XDR_DECODE: 643 if (nodesize == 0) { 644 return (TRUE); 645 } 646 if (sp == NULL) { 647 *cpp = sp = mem_alloc(nodesize); 648 allocated = TRUE; 649 } 650 if (sp == NULL) { 651 printf("xdr_string: out of memory"); 652 return (FALSE); 653 } 654 sp[size] = 0; 655 /* FALLTHROUGH */ 656 657 case XDR_ENCODE: 658 ret = xdr_opaque(xdrs, sp, size); 659 if ((xdrs->x_op == XDR_DECODE) && (ret == FALSE)) { 660 if (allocated == TRUE) { 661 mem_free(sp, nodesize); 662 *cpp = NULL; 663 } 664 } 665 return (ret); 666 667 case XDR_FREE: 668 mem_free(sp, nodesize); 669 *cpp = NULL; 670 return (TRUE); 671 } 672 /* NOTREACHED */ 673 return (FALSE); 674 } 675 676 /* 677 * Wrapper for xdr_string that can be called directly from 678 * routines like clnt_call 679 */ 680 bool_t 681 xdr_wrapstring(XDR *xdrs, char **cpp) 682 { 683 return xdr_string(xdrs, cpp, RPC_MAXDATASIZE); 684 } 685 686 /* 687 * NOTE: xdr_hyper(), xdr_u_hyper(), xdr_longlong_t(), and xdr_u_longlong_t() 688 * are in the "non-portable" section because they require that a `long long' 689 * be a 64-bit type. 690 * 691 * --thorpej@netbsd.org, November 30, 1999 692 */ 693 694 /* 695 * XDR 64-bit integers 696 */ 697 bool_t 698 xdr_int64_t(XDR *xdrs, int64_t *llp) 699 { 700 u_long ul[2]; 701 702 switch (xdrs->x_op) { 703 case XDR_ENCODE: 704 ul[0] = (u_long)((uint64_t)*llp >> 32) & 0xffffffff; 705 ul[1] = (u_long)((uint64_t)*llp) & 0xffffffff; 706 if (XDR_PUTLONG(xdrs, (long *)&ul[0]) == FALSE) 707 return (FALSE); 708 return (XDR_PUTLONG(xdrs, (long *)&ul[1])); 709 case XDR_DECODE: 710 if (XDR_GETLONG(xdrs, (long *)&ul[0]) == FALSE) 711 return (FALSE); 712 if (XDR_GETLONG(xdrs, (long *)&ul[1]) == FALSE) 713 return (FALSE); 714 *llp = (int64_t) 715 (((uint64_t)ul[0] << 32) | ((uint64_t)ul[1])); 716 return (TRUE); 717 case XDR_FREE: 718 return (TRUE); 719 } 720 /* NOTREACHED */ 721 return (FALSE); 722 } 723 724 /* 725 * XDR unsigned 64-bit integers 726 */ 727 bool_t 728 xdr_uint64_t(XDR *xdrs, uint64_t *ullp) 729 { 730 u_long ul[2]; 731 732 switch (xdrs->x_op) { 733 case XDR_ENCODE: 734 ul[0] = (u_long)(*ullp >> 32) & 0xffffffff; 735 ul[1] = (u_long)(*ullp) & 0xffffffff; 736 if (XDR_PUTLONG(xdrs, (long *)&ul[0]) == FALSE) 737 return (FALSE); 738 return (XDR_PUTLONG(xdrs, (long *)&ul[1])); 739 case XDR_DECODE: 740 if (XDR_GETLONG(xdrs, (long *)&ul[0]) == FALSE) 741 return (FALSE); 742 if (XDR_GETLONG(xdrs, (long *)&ul[1]) == FALSE) 743 return (FALSE); 744 *ullp = (uint64_t) 745 (((uint64_t)ul[0] << 32) | ((uint64_t)ul[1])); 746 return (TRUE); 747 case XDR_FREE: 748 return (TRUE); 749 } 750 /* NOTREACHED */ 751 return (FALSE); 752 } 753 754 /* 755 * XDR hypers 756 */ 757 bool_t 758 xdr_hyper(XDR *xdrs, longlong_t *llp) 759 { 760 761 /* 762 * Don't bother open-coding this; it's a fair amount of code. Just 763 * call xdr_int64_t(). 764 */ 765 return (xdr_int64_t(xdrs, (int64_t *)llp)); 766 } 767 768 /* 769 * XDR unsigned hypers 770 */ 771 bool_t 772 xdr_u_hyper(XDR *xdrs, u_longlong_t *ullp) 773 { 774 775 /* 776 * Don't bother open-coding this; it's a fair amount of code. Just 777 * call xdr_uint64_t(). 778 */ 779 return (xdr_uint64_t(xdrs, (uint64_t *)ullp)); 780 } 781 782 /* 783 * XDR longlong_t's 784 */ 785 bool_t 786 xdr_longlong_t(XDR *xdrs, longlong_t *llp) 787 { 788 789 /* 790 * Don't bother open-coding this; it's a fair amount of code. Just 791 * call xdr_int64_t(). 792 */ 793 return (xdr_int64_t(xdrs, (int64_t *)llp)); 794 } 795 796 /* 797 * XDR u_longlong_t's 798 */ 799 bool_t 800 xdr_u_longlong_t(XDR *xdrs, u_longlong_t *ullp) 801 { 802 803 /* 804 * Don't bother open-coding this; it's a fair amount of code. Just 805 * call xdr_uint64_t(). 806 */ 807 return (xdr_uint64_t(xdrs, (uint64_t *)ullp)); 808 } 809 810 /* 811 * Kernel module glue 812 */ 813 static int 814 xdr_modevent(module_t mod, int type, void *data) 815 { 816 817 return (0); 818 } 819 static moduledata_t xdr_mod = { 820 "xdr", 821 xdr_modevent, 822 NULL, 823 }; 824 DECLARE_MODULE(xdr, xdr_mod, SI_SUB_VFS, SI_ORDER_ANY); 825 MODULE_VERSION(xdr, 1); 826