1 /* $NetBSD: rdataslab.c,v 1.11 2015/07/08 17:28:59 christos Exp $ */
2
3 /*
4 * Copyright (C) 2004-2014 Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (C) 1999-2003 Internet Software Consortium.
6 *
7 * Permission to use, copy, modify, and/or distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
12 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
13 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
14 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
16 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
17 * PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 /* Id */
21
22 /*! \file */
23
24 #include <config.h>
25
26 #include <stdlib.h>
27
28 #include <isc/mem.h>
29 #include <isc/region.h>
30 #include <isc/string.h> /* Required for HP/UX (and others?) */
31 #include <isc/util.h>
32
33 #include <dns/result.h>
34 #include <dns/rdata.h>
35 #include <dns/rdataset.h>
36 #include <dns/rdataslab.h>
37
38 /*
39 * The rdataslab structure allows iteration to occur in both load order
40 * and DNSSEC order. The structure is as follows:
41 *
42 * header (reservelen bytes)
43 * record count (2 bytes)
44 * offset table (4 x record count bytes in load order)
45 * data records
46 * data length (2 bytes)
47 * order (2 bytes)
48 * meta data (1 byte for RRSIG's)
49 * data (data length bytes)
50 *
51 * If DNS_RDATASET_FIXED is defined to be zero (0) the format of a
52 * rdataslab is as follows:
53 *
54 * header (reservelen bytes)
55 * record count (2 bytes)
56 * data records
57 * data length (2 bytes)
58 * meta data (1 byte for RRSIG's)
59 * data (data length bytes)
60 *
61 * Offsets are from the end of the header.
62 *
63 * Load order traversal is performed by walking the offset table to find
64 * the start of the record (DNS_RDATASET_FIXED = 1).
65 *
66 * DNSSEC order traversal is performed by walking the data records.
67 *
68 * The order is stored with record to allow for efficient reconstruction
69 * of the offset table following a merge or subtraction.
70 *
71 * The iterator methods here currently only support DNSSEC order iteration.
72 *
73 * The iterator methods in rbtdb support both load order and DNSSEC order
74 * iteration.
75 *
76 * WARNING:
77 * rbtdb.c directly interacts with the slab's raw structures. If the
78 * structure changes then rbtdb.c also needs to be updated to reflect
79 * the changes. See the areas tagged with "RDATASLAB".
80 */
81
82 struct xrdata {
83 dns_rdata_t rdata;
84 unsigned int order;
85 };
86
87 /*% Note: the "const void *" are just to make qsort happy. */
88 static int
compare_rdata(const void * p1,const void * p2)89 compare_rdata(const void *p1, const void *p2) {
90 const struct xrdata *x1 = p1;
91 const struct xrdata *x2 = p2;
92 return (dns_rdata_compare(&x1->rdata, &x2->rdata));
93 }
94
95 #if DNS_RDATASET_FIXED
96 static void
fillin_offsets(unsigned char * offsetbase,unsigned int * offsettable,unsigned length)97 fillin_offsets(unsigned char *offsetbase, unsigned int *offsettable,
98 unsigned length)
99 {
100 unsigned int i, j;
101 unsigned char *raw;
102
103 for (i = 0, j = 0; i < length; i++) {
104
105 if (offsettable[i] == 0)
106 continue;
107
108 /*
109 * Fill in offset table.
110 */
111 raw = &offsetbase[j*4 + 2];
112 *raw++ = (offsettable[i] & 0xff000000) >> 24;
113 *raw++ = (offsettable[i] & 0xff0000) >> 16;
114 *raw++ = (offsettable[i] & 0xff00) >> 8;
115 *raw = offsettable[i] & 0xff;
116
117 /*
118 * Fill in table index.
119 */
120 raw = offsetbase + offsettable[i] + 2;
121 *raw++ = (j & 0xff00) >> 8;
122 *raw = j++ & 0xff;
123 }
124 }
125 #endif
126
127 isc_result_t
dns_rdataslab_fromrdataset(dns_rdataset_t * rdataset,isc_mem_t * mctx,isc_region_t * region,unsigned int reservelen)128 dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
129 isc_region_t *region, unsigned int reservelen)
130 {
131 /*
132 * Use &removed as a sentinal pointer for duplicate
133 * rdata as rdata.data == NULL is valid.
134 */
135 static unsigned char removed;
136 struct xrdata *x;
137 unsigned char *rawbuf;
138 #if DNS_RDATASET_FIXED
139 unsigned char *offsetbase;
140 #endif
141 unsigned int buflen;
142 isc_result_t result;
143 unsigned int nitems;
144 unsigned int nalloc;
145 unsigned int i;
146 #if DNS_RDATASET_FIXED
147 unsigned int *offsettable;
148 #endif
149 unsigned int length;
150
151 buflen = reservelen + 2;
152
153 nitems = dns_rdataset_count(rdataset);
154
155 /*
156 * If there are no rdata then we can just need to allocate a header
157 * with zero a record count.
158 */
159 if (nitems == 0) {
160 if (rdataset->type != 0)
161 return (ISC_R_FAILURE);
162 rawbuf = isc_mem_get(mctx, buflen);
163 if (rawbuf == NULL)
164 return (ISC_R_NOMEMORY);
165 region->base = rawbuf;
166 region->length = buflen;
167 rawbuf += reservelen;
168 *rawbuf++ = 0;
169 *rawbuf = 0;
170 return (ISC_R_SUCCESS);
171 }
172
173 if (nitems > 0xffff)
174 return (ISC_R_NOSPACE);
175
176 /*
177 * Remember the original number of items.
178 */
179 nalloc = nitems;
180 x = isc_mem_get(mctx, nalloc * sizeof(struct xrdata));
181 if (x == NULL)
182 return (ISC_R_NOMEMORY);
183
184 /*
185 * Save all of the rdata members into an array.
186 */
187 result = dns_rdataset_first(rdataset);
188 if (result != ISC_R_SUCCESS && result != ISC_R_NOMORE)
189 goto free_rdatas;
190 for (i = 0; i < nalloc && result == ISC_R_SUCCESS; i++) {
191 INSIST(result == ISC_R_SUCCESS);
192 dns_rdata_init(&x[i].rdata);
193 dns_rdataset_current(rdataset, &x[i].rdata);
194 INSIST(x[i].rdata.data != &removed);
195 #if DNS_RDATASET_FIXED
196 x[i].order = i;
197 #endif
198 result = dns_rdataset_next(rdataset);
199 }
200 if (i != nalloc || result != ISC_R_NOMORE) {
201 /*
202 * Somehow we iterated over fewer rdatas than
203 * dns_rdataset_count() said there were or there
204 * were more items than dns_rdataset_count said
205 * there were.
206 */
207 result = ISC_R_FAILURE;
208 goto free_rdatas;
209 }
210
211 /*
212 * Put into DNSSEC order.
213 */
214 if (nalloc > 1U)
215 qsort(x, nalloc, sizeof(struct xrdata), compare_rdata);
216
217 /*
218 * Remove duplicates and compute the total storage required.
219 *
220 * If an rdata is not a duplicate, accumulate the storage size
221 * required for the rdata. We do not store the class, type, etc,
222 * just the rdata, so our overhead is 2 bytes for the number of
223 * records, and 8 for each rdata, (length(2), offset(4) and order(2))
224 * and then the rdata itself.
225 */
226 for (i = 1; i < nalloc; i++) {
227 if (compare_rdata(&x[i-1].rdata, &x[i].rdata) == 0) {
228 x[i-1].rdata.data = &removed;
229 #if DNS_RDATASET_FIXED
230 /*
231 * Preserve the least order so A, B, A -> A, B
232 * after duplicate removal.
233 */
234 if (x[i-1].order < x[i].order)
235 x[i].order = x[i-1].order;
236 #endif
237 nitems--;
238 } else {
239 #if DNS_RDATASET_FIXED
240 buflen += (8 + x[i-1].rdata.length);
241 #else
242 buflen += (2 + x[i-1].rdata.length);
243 #endif
244 /*
245 * Provide space to store the per RR meta data.
246 */
247 if (rdataset->type == dns_rdatatype_rrsig)
248 buflen++;
249 }
250 }
251
252 /*
253 * Don't forget the last item!
254 */
255 #if DNS_RDATASET_FIXED
256 buflen += (8 + x[i-1].rdata.length);
257 #else
258 buflen += (2 + x[i-1].rdata.length);
259 #endif
260 /*
261 * Provide space to store the per RR meta data.
262 */
263 if (rdataset->type == dns_rdatatype_rrsig)
264 buflen++;
265
266 /*
267 * Ensure that singleton types are actually singletons.
268 */
269 if (nitems > 1 && dns_rdatatype_issingleton(rdataset->type)) {
270 /*
271 * We have a singleton type, but there's more than one
272 * RR in the rdataset.
273 */
274 result = DNS_R_SINGLETON;
275 goto free_rdatas;
276 }
277
278 /*
279 * Allocate the memory, set up a buffer, start copying in
280 * data.
281 */
282 rawbuf = isc_mem_get(mctx, buflen);
283 if (rawbuf == NULL) {
284 result = ISC_R_NOMEMORY;
285 goto free_rdatas;
286 }
287
288 #if DNS_RDATASET_FIXED
289 /* Allocate temporary offset table. */
290 offsettable = isc_mem_get(mctx, nalloc * sizeof(unsigned int));
291 if (offsettable == NULL) {
292 isc_mem_put(mctx, rawbuf, buflen);
293 result = ISC_R_NOMEMORY;
294 goto free_rdatas;
295 }
296 memset(offsettable, 0, nalloc * sizeof(unsigned int));
297 #endif
298
299 region->base = rawbuf;
300 region->length = buflen;
301
302 rawbuf += reservelen;
303 #if DNS_RDATASET_FIXED
304 offsetbase = rawbuf;
305 #endif
306
307 *rawbuf++ = (nitems & 0xff00) >> 8;
308 *rawbuf++ = (nitems & 0x00ff);
309
310 #if DNS_RDATASET_FIXED
311 /* Skip load order table. Filled in later. */
312 rawbuf += nitems * 4;
313 #endif
314
315 for (i = 0; i < nalloc; i++) {
316 if (x[i].rdata.data == &removed)
317 continue;
318 #if DNS_RDATASET_FIXED
319 offsettable[x[i].order] = rawbuf - offsetbase;
320 #endif
321 length = x[i].rdata.length;
322 if (rdataset->type == dns_rdatatype_rrsig)
323 length++;
324 INSIST(length <= 0xffff);
325 *rawbuf++ = (length & 0xff00) >> 8;
326 *rawbuf++ = (length & 0x00ff);
327 #if DNS_RDATASET_FIXED
328 rawbuf += 2; /* filled in later */
329 #endif
330 /*
331 * Store the per RR meta data.
332 */
333 if (rdataset->type == dns_rdatatype_rrsig) {
334 *rawbuf++ |= (x[i].rdata.flags & DNS_RDATA_OFFLINE) ?
335 DNS_RDATASLAB_OFFLINE : 0;
336 }
337 memmove(rawbuf, x[i].rdata.data, x[i].rdata.length);
338 rawbuf += x[i].rdata.length;
339 }
340
341 #if DNS_RDATASET_FIXED
342 fillin_offsets(offsetbase, offsettable, nalloc);
343 isc_mem_put(mctx, offsettable, nalloc * sizeof(unsigned int));
344 #endif
345
346 result = ISC_R_SUCCESS;
347
348 free_rdatas:
349 isc_mem_put(mctx, x, nalloc * sizeof(struct xrdata));
350 return (result);
351 }
352
353 static void
rdataset_disassociate(dns_rdataset_t * rdataset)354 rdataset_disassociate(dns_rdataset_t *rdataset) {
355 UNUSED(rdataset);
356 }
357
358 static isc_result_t
rdataset_first(dns_rdataset_t * rdataset)359 rdataset_first(dns_rdataset_t *rdataset) {
360 unsigned char *raw = rdataset->private3;
361 unsigned int count;
362
363 count = raw[0] * 256 + raw[1];
364 if (count == 0) {
365 rdataset->private5 = NULL;
366 return (ISC_R_NOMORE);
367 }
368 #if DNS_RDATASET_FIXED
369 raw += 2 + (4 * count);
370 #else
371 raw += 2;
372 #endif
373 /*
374 * The privateuint4 field is the number of rdata beyond the cursor
375 * position, so we decrement the total count by one before storing
376 * it.
377 */
378 count--;
379 rdataset->privateuint4 = count;
380 rdataset->private5 = raw;
381
382 return (ISC_R_SUCCESS);
383 }
384
385 static isc_result_t
rdataset_next(dns_rdataset_t * rdataset)386 rdataset_next(dns_rdataset_t *rdataset) {
387 unsigned int count;
388 unsigned int length;
389 unsigned char *raw;
390
391 count = rdataset->privateuint4;
392 if (count == 0)
393 return (ISC_R_NOMORE);
394 count--;
395 rdataset->privateuint4 = count;
396 raw = rdataset->private5;
397 length = raw[0] * 256 + raw[1];
398 #if DNS_RDATASET_FIXED
399 raw += length + 4;
400 #else
401 raw += length + 2;
402 #endif
403 rdataset->private5 = raw;
404
405 return (ISC_R_SUCCESS);
406 }
407
408 static void
rdataset_current(dns_rdataset_t * rdataset,dns_rdata_t * rdata)409 rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
410 unsigned char *raw = rdataset->private5;
411 isc_region_t r;
412 unsigned int length;
413 unsigned int flags = 0;
414
415 REQUIRE(raw != NULL);
416
417 length = raw[0] * 256 + raw[1];
418 #if DNS_RDATASET_FIXED
419 raw += 4;
420 #else
421 raw += 2;
422 #endif
423 if (rdataset->type == dns_rdatatype_rrsig) {
424 if (*raw & DNS_RDATASLAB_OFFLINE)
425 flags |= DNS_RDATA_OFFLINE;
426 length--;
427 raw++;
428 }
429 r.length = length;
430 r.base = raw;
431 dns_rdata_fromregion(rdata, rdataset->rdclass, rdataset->type, &r);
432 rdata->flags |= flags;
433 }
434
435 static void
rdataset_clone(dns_rdataset_t * source,dns_rdataset_t * target)436 rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
437 *target = *source;
438
439 /*
440 * Reset iterator state.
441 */
442 target->privateuint4 = 0;
443 target->private5 = NULL;
444 }
445
446 static unsigned int
rdataset_count(dns_rdataset_t * rdataset)447 rdataset_count(dns_rdataset_t *rdataset) {
448 unsigned char *raw = rdataset->private3;
449 unsigned int count;
450
451 count = raw[0] * 256 + raw[1];
452
453 return (count);
454 }
455
456 static dns_rdatasetmethods_t rdataset_methods = {
457 rdataset_disassociate,
458 rdataset_first,
459 rdataset_next,
460 rdataset_current,
461 rdataset_clone,
462 rdataset_count,
463 NULL,
464 NULL,
465 NULL,
466 NULL,
467 NULL,
468 NULL,
469 NULL,
470 NULL,
471 NULL,
472 NULL
473 };
474
475 void
dns_rdataslab_tordataset(unsigned char * slab,unsigned int reservelen,dns_rdataclass_t rdclass,dns_rdatatype_t rdtype,dns_rdatatype_t covers,dns_ttl_t ttl,dns_rdataset_t * rdataset)476 dns_rdataslab_tordataset(unsigned char *slab, unsigned int reservelen,
477 dns_rdataclass_t rdclass, dns_rdatatype_t rdtype,
478 dns_rdatatype_t covers, dns_ttl_t ttl,
479 dns_rdataset_t *rdataset)
480 {
481 REQUIRE(slab != NULL);
482 REQUIRE(!dns_rdataset_isassociated(rdataset));
483
484 rdataset->methods = &rdataset_methods;
485 rdataset->rdclass = rdclass;
486 rdataset->type = rdtype;
487 rdataset->covers = covers;
488 rdataset->ttl = ttl;
489 rdataset->trust = 0;
490 rdataset->private1 = NULL;
491 rdataset->private2 = NULL;
492 rdataset->private3 = slab + reservelen;
493
494 /*
495 * Reset iterator state.
496 */
497 rdataset->privateuint4 = 0;
498 rdataset->private5 = NULL;
499 }
500
501 unsigned int
dns_rdataslab_size(unsigned char * slab,unsigned int reservelen)502 dns_rdataslab_size(unsigned char *slab, unsigned int reservelen) {
503 unsigned int count, length;
504 unsigned char *current;
505
506 REQUIRE(slab != NULL);
507
508 current = slab + reservelen;
509 count = *current++ * 256;
510 count += *current++;
511 #if DNS_RDATASET_FIXED
512 current += (4 * count);
513 #endif
514 while (count > 0) {
515 count--;
516 length = *current++ * 256;
517 length += *current++;
518 #if DNS_RDATASET_FIXED
519 current += length + 2;
520 #else
521 current += length;
522 #endif
523 }
524
525 return ((unsigned int)(current - slab));
526 }
527
528 /*
529 * Make the dns_rdata_t 'rdata' refer to the slab item
530 * beginning at '*current', which is part of a slab of type
531 * 'type' and class 'rdclass', and advance '*current' to
532 * point to the next item in the slab.
533 */
534 static inline void
rdata_from_slab(unsigned char ** current,dns_rdataclass_t rdclass,dns_rdatatype_t type,dns_rdata_t * rdata)535 rdata_from_slab(unsigned char **current,
536 dns_rdataclass_t rdclass, dns_rdatatype_t type,
537 dns_rdata_t *rdata)
538 {
539 unsigned char *tcurrent = *current;
540 isc_region_t region;
541 unsigned int length;
542 isc_boolean_t offline = ISC_FALSE;
543
544 length = *tcurrent++ * 256;
545 length += *tcurrent++;
546
547 if (type == dns_rdatatype_rrsig) {
548 if ((*tcurrent & DNS_RDATASLAB_OFFLINE) != 0)
549 offline = ISC_TRUE;
550 length--;
551 tcurrent++;
552 }
553 region.length = length;
554 #if DNS_RDATASET_FIXED
555 tcurrent += 2;
556 #endif
557 region.base = tcurrent;
558 tcurrent += region.length;
559 dns_rdata_fromregion(rdata, rdclass, type, ®ion);
560 if (offline)
561 rdata->flags |= DNS_RDATA_OFFLINE;
562 *current = tcurrent;
563 }
564
565 /*
566 * Return true iff 'slab' (slab data of type 'type' and class 'rdclass')
567 * contains an rdata identical to 'rdata'. This does case insensitive
568 * comparisons per DNSSEC.
569 */
570 static inline isc_boolean_t
rdata_in_slab(unsigned char * slab,unsigned int reservelen,dns_rdataclass_t rdclass,dns_rdatatype_t type,dns_rdata_t * rdata)571 rdata_in_slab(unsigned char *slab, unsigned int reservelen,
572 dns_rdataclass_t rdclass, dns_rdatatype_t type,
573 dns_rdata_t *rdata)
574 {
575 unsigned int count, i;
576 unsigned char *current;
577 dns_rdata_t trdata = DNS_RDATA_INIT;
578 int n;
579
580 current = slab + reservelen;
581 count = *current++ * 256;
582 count += *current++;
583
584 #if DNS_RDATASET_FIXED
585 current += (4 * count);
586 #endif
587
588 for (i = 0; i < count; i++) {
589 rdata_from_slab(¤t, rdclass, type, &trdata);
590
591 n = dns_rdata_compare(&trdata, rdata);
592 if (n == 0)
593 return (ISC_TRUE);
594 if (n > 0) /* In DNSSEC order. */
595 break;
596 dns_rdata_reset(&trdata);
597 }
598 return (ISC_FALSE);
599 }
600
601 isc_result_t
dns_rdataslab_merge(unsigned char * oslab,unsigned char * nslab,unsigned int reservelen,isc_mem_t * mctx,dns_rdataclass_t rdclass,dns_rdatatype_t type,unsigned int flags,unsigned char ** tslabp)602 dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
603 unsigned int reservelen, isc_mem_t *mctx,
604 dns_rdataclass_t rdclass, dns_rdatatype_t type,
605 unsigned int flags, unsigned char **tslabp)
606 {
607 unsigned char *ocurrent, *ostart, *ncurrent, *tstart, *tcurrent, *data;
608 unsigned int ocount, ncount, count, olength, tlength, tcount, length;
609 dns_rdata_t ordata = DNS_RDATA_INIT;
610 dns_rdata_t nrdata = DNS_RDATA_INIT;
611 isc_boolean_t added_something = ISC_FALSE;
612 unsigned int oadded = 0;
613 unsigned int nadded = 0;
614 unsigned int nncount = 0;
615 #if DNS_RDATASET_FIXED
616 unsigned int oncount;
617 unsigned int norder = 0;
618 unsigned int oorder = 0;
619 unsigned char *offsetbase;
620 unsigned int *offsettable;
621 #endif
622
623 /*
624 * XXX Need parameter to allow "delete rdatasets in nslab" merge,
625 * or perhaps another merge routine for this purpose.
626 */
627
628 REQUIRE(tslabp != NULL && *tslabp == NULL);
629 REQUIRE(oslab != NULL && nslab != NULL);
630
631 ocurrent = oslab + reservelen;
632 ocount = *ocurrent++ * 256;
633 ocount += *ocurrent++;
634 #if DNS_RDATASET_FIXED
635 ocurrent += (4 * ocount);
636 #endif
637 ostart = ocurrent;
638 ncurrent = nslab + reservelen;
639 ncount = *ncurrent++ * 256;
640 ncount += *ncurrent++;
641 #if DNS_RDATASET_FIXED
642 ncurrent += (4 * ncount);
643 #endif
644 INSIST(ocount > 0 && ncount > 0);
645
646 #if DNS_RDATASET_FIXED
647 oncount = ncount;
648 #endif
649
650 /*
651 * Yes, this is inefficient!
652 */
653
654 /*
655 * Figure out the length of the old slab's data.
656 */
657 olength = 0;
658 for (count = 0; count < ocount; count++) {
659 length = *ocurrent++ * 256;
660 length += *ocurrent++;
661 #if DNS_RDATASET_FIXED
662 olength += length + 8;
663 ocurrent += length + 2;
664 #else
665 olength += length + 2;
666 ocurrent += length;
667 #endif
668 }
669
670 /*
671 * Start figuring out the target length and count.
672 */
673 tlength = reservelen + 2 + olength;
674 tcount = ocount;
675
676 /*
677 * Add in the length of rdata in the new slab that aren't in
678 * the old slab.
679 */
680 do {
681 dns_rdata_init(&nrdata);
682 rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
683 if (!rdata_in_slab(oslab, reservelen, rdclass, type, &nrdata))
684 {
685 /*
686 * This rdata isn't in the old slab.
687 */
688 #if DNS_RDATASET_FIXED
689 tlength += nrdata.length + 8;
690 #else
691 tlength += nrdata.length + 2;
692 #endif
693 if (type == dns_rdatatype_rrsig)
694 tlength++;
695 tcount++;
696 nncount++;
697 added_something = ISC_TRUE;
698 }
699 ncount--;
700 } while (ncount > 0);
701 ncount = nncount;
702
703 if (((flags & DNS_RDATASLAB_EXACT) != 0) &&
704 (tcount != ncount + ocount))
705 return (DNS_R_NOTEXACT);
706
707 if (!added_something && (flags & DNS_RDATASLAB_FORCE) == 0)
708 return (DNS_R_UNCHANGED);
709
710 /*
711 * Ensure that singleton types are actually singletons.
712 */
713 if (tcount > 1 && dns_rdatatype_issingleton(type)) {
714 /*
715 * We have a singleton type, but there's more than one
716 * RR in the rdataset.
717 */
718 return (DNS_R_SINGLETON);
719 }
720
721 if (tcount > 0xffff)
722 return (ISC_R_NOSPACE);
723
724 /*
725 * Copy the reserved area from the new slab.
726 */
727 tstart = isc_mem_get(mctx, tlength);
728 if (tstart == NULL)
729 return (ISC_R_NOMEMORY);
730 memmove(tstart, nslab, reservelen);
731 tcurrent = tstart + reservelen;
732 #if DNS_RDATASET_FIXED
733 offsetbase = tcurrent;
734 #endif
735
736 /*
737 * Write the new count.
738 */
739 *tcurrent++ = (tcount & 0xff00) >> 8;
740 *tcurrent++ = (tcount & 0x00ff);
741
742 #if DNS_RDATASET_FIXED
743 /*
744 * Skip offset table.
745 */
746 tcurrent += (tcount * 4);
747
748 offsettable = isc_mem_get(mctx,
749 (ocount + oncount) * sizeof(unsigned int));
750 if (offsettable == NULL) {
751 isc_mem_put(mctx, tstart, tlength);
752 return (ISC_R_NOMEMORY);
753 }
754 memset(offsettable, 0, (ocount + oncount) * sizeof(unsigned int));
755 #endif
756
757 /*
758 * Merge the two slabs.
759 */
760 ocurrent = ostart;
761 INSIST(ocount != 0);
762 #if DNS_RDATASET_FIXED
763 oorder = ocurrent[2] * 256 + ocurrent[3];
764 INSIST(oorder < ocount);
765 #endif
766 rdata_from_slab(&ocurrent, rdclass, type, &ordata);
767
768 ncurrent = nslab + reservelen + 2;
769 #if DNS_RDATASET_FIXED
770 ncurrent += (4 * oncount);
771 #endif
772
773 if (ncount > 0) {
774 do {
775 dns_rdata_reset(&nrdata);
776 #if DNS_RDATASET_FIXED
777 norder = ncurrent[2] * 256 + ncurrent[3];
778
779 INSIST(norder < oncount);
780 #endif
781 rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
782 } while (rdata_in_slab(oslab, reservelen, rdclass,
783 type, &nrdata));
784 }
785
786 while (oadded < ocount || nadded < ncount) {
787 isc_boolean_t fromold;
788 if (oadded == ocount)
789 fromold = ISC_FALSE;
790 else if (nadded == ncount)
791 fromold = ISC_TRUE;
792 else
793 fromold = ISC_TF(compare_rdata(&ordata, &nrdata) < 0);
794 if (fromold) {
795 #if DNS_RDATASET_FIXED
796 offsettable[oorder] = tcurrent - offsetbase;
797 #endif
798 length = ordata.length;
799 data = ordata.data;
800 if (type == dns_rdatatype_rrsig) {
801 length++;
802 data--;
803 }
804 *tcurrent++ = (length & 0xff00) >> 8;
805 *tcurrent++ = (length & 0x00ff);
806 #if DNS_RDATASET_FIXED
807 tcurrent += 2; /* fill in later */
808 #endif
809 memmove(tcurrent, data, length);
810 tcurrent += length;
811 oadded++;
812 if (oadded < ocount) {
813 dns_rdata_reset(&ordata);
814 #if DNS_RDATASET_FIXED
815 oorder = ocurrent[2] * 256 + ocurrent[3];
816 INSIST(oorder < ocount);
817 #endif
818 rdata_from_slab(&ocurrent, rdclass, type,
819 &ordata);
820 }
821 } else {
822 #if DNS_RDATASET_FIXED
823 offsettable[ocount + norder] = tcurrent - offsetbase;
824 #endif
825 length = nrdata.length;
826 data = nrdata.data;
827 if (type == dns_rdatatype_rrsig) {
828 length++;
829 data--;
830 }
831 *tcurrent++ = (length & 0xff00) >> 8;
832 *tcurrent++ = (length & 0x00ff);
833 #if DNS_RDATASET_FIXED
834 tcurrent += 2; /* fill in later */
835 #endif
836 memmove(tcurrent, data, length);
837 tcurrent += length;
838 nadded++;
839 if (nadded < ncount) {
840 do {
841 dns_rdata_reset(&nrdata);
842 #if DNS_RDATASET_FIXED
843 norder = ncurrent[2] * 256 + ncurrent[3];
844 INSIST(norder < oncount);
845 #endif
846 rdata_from_slab(&ncurrent, rdclass,
847 type, &nrdata);
848 } while (rdata_in_slab(oslab, reservelen,
849 rdclass, type,
850 &nrdata));
851 }
852 }
853 }
854
855 #if DNS_RDATASET_FIXED
856 fillin_offsets(offsetbase, offsettable, ocount + oncount);
857
858 isc_mem_put(mctx, offsettable,
859 (ocount + oncount) * sizeof(unsigned int));
860 #endif
861
862 INSIST(tcurrent == tstart + tlength);
863
864 *tslabp = tstart;
865
866 return (ISC_R_SUCCESS);
867 }
868
869 isc_result_t
dns_rdataslab_subtract(unsigned char * mslab,unsigned char * sslab,unsigned int reservelen,isc_mem_t * mctx,dns_rdataclass_t rdclass,dns_rdatatype_t type,unsigned int flags,unsigned char ** tslabp)870 dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
871 unsigned int reservelen, isc_mem_t *mctx,
872 dns_rdataclass_t rdclass, dns_rdatatype_t type,
873 unsigned int flags, unsigned char **tslabp)
874 {
875 unsigned char *mcurrent, *sstart, *scurrent, *tstart, *tcurrent;
876 unsigned int mcount, scount, rcount ,count, tlength, tcount, i;
877 dns_rdata_t srdata = DNS_RDATA_INIT;
878 dns_rdata_t mrdata = DNS_RDATA_INIT;
879 #if DNS_RDATASET_FIXED
880 unsigned char *offsetbase;
881 unsigned int *offsettable;
882 unsigned int order;
883 #endif
884
885 REQUIRE(tslabp != NULL && *tslabp == NULL);
886 REQUIRE(mslab != NULL && sslab != NULL);
887
888 mcurrent = mslab + reservelen;
889 mcount = *mcurrent++ * 256;
890 mcount += *mcurrent++;
891 scurrent = sslab + reservelen;
892 scount = *scurrent++ * 256;
893 scount += *scurrent++;
894 INSIST(mcount > 0 && scount > 0);
895
896 /*
897 * Yes, this is inefficient!
898 */
899
900 /*
901 * Start figuring out the target length and count.
902 */
903 tlength = reservelen + 2;
904 tcount = 0;
905 rcount = 0;
906
907 #if DNS_RDATASET_FIXED
908 mcurrent += 4 * mcount;
909 scurrent += 4 * scount;
910 #endif
911 sstart = scurrent;
912
913 /*
914 * Add in the length of rdata in the mslab that aren't in
915 * the sslab.
916 */
917 for (i = 0; i < mcount; i++) {
918 unsigned char *mrdatabegin = mcurrent;
919 rdata_from_slab(&mcurrent, rdclass, type, &mrdata);
920 scurrent = sstart;
921 for (count = 0; count < scount; count++) {
922 dns_rdata_reset(&srdata);
923 rdata_from_slab(&scurrent, rdclass, type, &srdata);
924 if (dns_rdata_compare(&mrdata, &srdata) == 0)
925 break;
926 }
927 if (count == scount) {
928 /*
929 * This rdata isn't in the sslab, and thus isn't
930 * being subtracted.
931 */
932 tlength += (unsigned int)(mcurrent - mrdatabegin);
933 tcount++;
934 } else
935 rcount++;
936 dns_rdata_reset(&mrdata);
937 }
938
939 #if DNS_RDATASET_FIXED
940 tlength += (4 * tcount);
941 #endif
942
943 /*
944 * Check that all the records originally existed. The numeric
945 * check only works as rdataslabs do not contain duplicates.
946 */
947 if (((flags & DNS_RDATASLAB_EXACT) != 0) && (rcount != scount))
948 return (DNS_R_NOTEXACT);
949
950 /*
951 * Don't continue if the new rdataslab would be empty.
952 */
953 if (tcount == 0)
954 return (DNS_R_NXRRSET);
955
956 /*
957 * If nothing is going to change, we can stop.
958 */
959 if (rcount == 0)
960 return (DNS_R_UNCHANGED);
961
962 /*
963 * Copy the reserved area from the mslab.
964 */
965 tstart = isc_mem_get(mctx, tlength);
966 if (tstart == NULL)
967 return (ISC_R_NOMEMORY);
968 memmove(tstart, mslab, reservelen);
969 tcurrent = tstart + reservelen;
970 #if DNS_RDATASET_FIXED
971 offsetbase = tcurrent;
972
973 offsettable = isc_mem_get(mctx, mcount * sizeof(unsigned int));
974 if (offsettable == NULL) {
975 isc_mem_put(mctx, tstart, tlength);
976 return (ISC_R_NOMEMORY);
977 }
978 memset(offsettable, 0, mcount * sizeof(unsigned int));
979 #endif
980
981 /*
982 * Write the new count.
983 */
984 *tcurrent++ = (tcount & 0xff00) >> 8;
985 *tcurrent++ = (tcount & 0x00ff);
986
987 #if DNS_RDATASET_FIXED
988 tcurrent += (4 * tcount);
989 #endif
990
991 /*
992 * Copy the parts of mslab not in sslab.
993 */
994 mcurrent = mslab + reservelen;
995 mcount = *mcurrent++ * 256;
996 mcount += *mcurrent++;
997 #if DNS_RDATASET_FIXED
998 mcurrent += (4 * mcount);
999 #endif
1000 for (i = 0; i < mcount; i++) {
1001 unsigned char *mrdatabegin = mcurrent;
1002 #if DNS_RDATASET_FIXED
1003 order = mcurrent[2] * 256 + mcurrent[3];
1004 INSIST(order < mcount);
1005 #endif
1006 rdata_from_slab(&mcurrent, rdclass, type, &mrdata);
1007 scurrent = sstart;
1008 for (count = 0; count < scount; count++) {
1009 dns_rdata_reset(&srdata);
1010 rdata_from_slab(&scurrent, rdclass, type, &srdata);
1011 if (dns_rdata_compare(&mrdata, &srdata) == 0)
1012 break;
1013 }
1014 if (count == scount) {
1015 /*
1016 * This rdata isn't in the sslab, and thus should be
1017 * copied to the tslab.
1018 */
1019 unsigned int length;
1020 length = (unsigned int)(mcurrent - mrdatabegin);
1021 #if DNS_RDATASET_FIXED
1022 offsettable[order] = tcurrent - offsetbase;
1023 #endif
1024 memmove(tcurrent, mrdatabegin, length);
1025 tcurrent += length;
1026 }
1027 dns_rdata_reset(&mrdata);
1028 }
1029
1030 #if DNS_RDATASET_FIXED
1031 fillin_offsets(offsetbase, offsettable, mcount);
1032
1033 isc_mem_put(mctx, offsettable, mcount * sizeof(unsigned int));
1034 #endif
1035
1036 INSIST(tcurrent == tstart + tlength);
1037
1038 *tslabp = tstart;
1039
1040 return (ISC_R_SUCCESS);
1041 }
1042
1043 isc_boolean_t
dns_rdataslab_equal(unsigned char * slab1,unsigned char * slab2,unsigned int reservelen)1044 dns_rdataslab_equal(unsigned char *slab1, unsigned char *slab2,
1045 unsigned int reservelen)
1046 {
1047 unsigned char *current1, *current2;
1048 unsigned int count1, count2;
1049 unsigned int length1, length2;
1050
1051 current1 = slab1 + reservelen;
1052 count1 = *current1++ * 256;
1053 count1 += *current1++;
1054
1055 current2 = slab2 + reservelen;
1056 count2 = *current2++ * 256;
1057 count2 += *current2++;
1058
1059 if (count1 != count2)
1060 return (ISC_FALSE);
1061
1062 #if DNS_RDATASET_FIXED
1063 current1 += (4 * count1);
1064 current2 += (4 * count2);
1065 #endif
1066
1067 while (count1 > 0) {
1068 length1 = *current1++ * 256;
1069 length1 += *current1++;
1070
1071 length2 = *current2++ * 256;
1072 length2 += *current2++;
1073
1074 #if DNS_RDATASET_FIXED
1075 current1 += 2;
1076 current2 += 2;
1077 #endif
1078
1079 if (length1 != length2 ||
1080 memcmp(current1, current2, length1) != 0)
1081 return (ISC_FALSE);
1082
1083 current1 += length1;
1084 current2 += length1;
1085
1086 count1--;
1087 }
1088 return (ISC_TRUE);
1089 }
1090
1091 isc_boolean_t
dns_rdataslab_equalx(unsigned char * slab1,unsigned char * slab2,unsigned int reservelen,dns_rdataclass_t rdclass,dns_rdatatype_t type)1092 dns_rdataslab_equalx(unsigned char *slab1, unsigned char *slab2,
1093 unsigned int reservelen, dns_rdataclass_t rdclass,
1094 dns_rdatatype_t type)
1095 {
1096 unsigned char *current1, *current2;
1097 unsigned int count1, count2;
1098 dns_rdata_t rdata1 = DNS_RDATA_INIT;
1099 dns_rdata_t rdata2 = DNS_RDATA_INIT;
1100
1101 current1 = slab1 + reservelen;
1102 count1 = *current1++ * 256;
1103 count1 += *current1++;
1104
1105 current2 = slab2 + reservelen;
1106 count2 = *current2++ * 256;
1107 count2 += *current2++;
1108
1109 if (count1 != count2)
1110 return (ISC_FALSE);
1111
1112 #if DNS_RDATASET_FIXED
1113 current1 += (4 * count1);
1114 current2 += (4 * count2);
1115 #endif
1116
1117 while (count1-- > 0) {
1118 rdata_from_slab(¤t1, rdclass, type, &rdata1);
1119 rdata_from_slab(¤t2, rdclass, type, &rdata2);
1120 if (dns_rdata_compare(&rdata1, &rdata2) != 0)
1121 return (ISC_FALSE);
1122 dns_rdata_reset(&rdata1);
1123 dns_rdata_reset(&rdata2);
1124 }
1125 return (ISC_TRUE);
1126 }
1127