1 /*
2 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
3 *
4 * SPDX-License-Identifier: MPL-2.0
5 *
6 * This Source Code Form is subject to the terms of the Mozilla Public
7 * License, v. 2.0. If a copy of the MPL was not distributed with this
8 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
9 *
10 * See the COPYRIGHT file distributed with this work for additional
11 * information regarding copyright ownership.
12 */
13
14 /*! \file */
15
16 #include <stdbool.h>
17 #include <stdlib.h>
18
19 #include <isc/mem.h>
20 #include <isc/region.h>
21 #include <isc/string.h> /* Required for HP/UX (and others?) */
22 #include <isc/util.h>
23
24 #include <dns/rdata.h>
25 #include <dns/rdataset.h>
26 #include <dns/rdataslab.h>
27 #include <dns/result.h>
28
29 /*
30 * The rdataslab structure allows iteration to occur in both load order
31 * and DNSSEC order. The structure is as follows:
32 *
33 * header (reservelen bytes)
34 * record count (2 bytes)
35 * offset table (4 x record count bytes in load order)
36 * data records
37 * data length (2 bytes)
38 * order (2 bytes)
39 * meta data (1 byte for RRSIG's)
40 * data (data length bytes)
41 *
42 * If DNS_RDATASET_FIXED is defined to be zero (0) the format of a
43 * rdataslab is as follows:
44 *
45 * header (reservelen bytes)
46 * record count (2 bytes)
47 * data records
48 * data length (2 bytes)
49 * meta data (1 byte for RRSIG's)
50 * data (data length bytes)
51 *
52 * Offsets are from the end of the header.
53 *
54 * Load order traversal is performed by walking the offset table to find
55 * the start of the record (DNS_RDATASET_FIXED = 1).
56 *
57 * DNSSEC order traversal is performed by walking the data records.
58 *
59 * The order is stored with record to allow for efficient reconstruction
60 * of the offset table following a merge or subtraction.
61 *
62 * The iterator methods in rbtdb support both load order and DNSSEC order
63 * iteration.
64 *
65 * WARNING:
66 * rbtdb.c directly interacts with the slab's raw structures. If the
67 * structure changes then rbtdb.c also needs to be updated to reflect
68 * the changes. See the areas tagged with "RDATASLAB".
69 */
70
71 struct xrdata {
72 dns_rdata_t rdata;
73 unsigned int order;
74 };
75
76 /*% Note: the "const void *" are just to make qsort happy. */
77 static int
compare_rdata(const void * p1,const void * p2)78 compare_rdata(const void *p1, const void *p2) {
79 const struct xrdata *x1 = p1;
80 const struct xrdata *x2 = p2;
81 return (dns_rdata_compare(&x1->rdata, &x2->rdata));
82 }
83
84 #if DNS_RDATASET_FIXED
85 static void
fillin_offsets(unsigned char * offsetbase,unsigned int * offsettable,unsigned length)86 fillin_offsets(unsigned char *offsetbase, unsigned int *offsettable,
87 unsigned length) {
88 unsigned int i, j;
89 unsigned char *raw;
90
91 for (i = 0, j = 0; i < length; i++) {
92 if (offsettable[i] == 0) {
93 continue;
94 }
95
96 /*
97 * Fill in offset table.
98 */
99 raw = &offsetbase[j * 4 + 2];
100 *raw++ = (offsettable[i] & 0xff000000) >> 24;
101 *raw++ = (offsettable[i] & 0xff0000) >> 16;
102 *raw++ = (offsettable[i] & 0xff00) >> 8;
103 *raw = offsettable[i] & 0xff;
104
105 /*
106 * Fill in table index.
107 */
108 raw = offsetbase + offsettable[i] + 2;
109 *raw++ = (j & 0xff00) >> 8;
110 *raw = j++ & 0xff;
111 }
112 }
113 #endif /* if DNS_RDATASET_FIXED */
114
115 isc_result_t
dns_rdataslab_fromrdataset(dns_rdataset_t * rdataset,isc_mem_t * mctx,isc_region_t * region,unsigned int reservelen)116 dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
117 isc_region_t *region, unsigned int reservelen) {
118 /*
119 * Use &removed as a sentinel pointer for duplicate
120 * rdata as rdata.data == NULL is valid.
121 */
122 static unsigned char removed;
123 struct xrdata *x;
124 unsigned char *rawbuf;
125 #if DNS_RDATASET_FIXED
126 unsigned char *offsetbase;
127 #endif /* if DNS_RDATASET_FIXED */
128 unsigned int buflen;
129 isc_result_t result;
130 unsigned int nitems;
131 unsigned int nalloc;
132 unsigned int i;
133 #if DNS_RDATASET_FIXED
134 unsigned int *offsettable;
135 #endif /* if DNS_RDATASET_FIXED */
136 unsigned int length;
137
138 buflen = reservelen + 2;
139
140 nitems = dns_rdataset_count(rdataset);
141
142 /*
143 * If there are no rdata then we can just need to allocate a header
144 * with zero a record count.
145 */
146 if (nitems == 0) {
147 if (rdataset->type != 0) {
148 return (ISC_R_FAILURE);
149 }
150 rawbuf = isc_mem_get(mctx, buflen);
151 region->base = rawbuf;
152 region->length = buflen;
153 rawbuf += reservelen;
154 *rawbuf++ = 0;
155 *rawbuf = 0;
156 return (ISC_R_SUCCESS);
157 }
158
159 if (nitems > 0xffff) {
160 return (ISC_R_NOSPACE);
161 }
162
163 /*
164 * Remember the original number of items.
165 */
166 nalloc = nitems;
167 x = isc_mem_get(mctx, nalloc * sizeof(struct xrdata));
168
169 /*
170 * Save all of the rdata members into an array.
171 */
172 result = dns_rdataset_first(rdataset);
173 if (result != ISC_R_SUCCESS && result != ISC_R_NOMORE) {
174 goto free_rdatas;
175 }
176 for (i = 0; i < nalloc && result == ISC_R_SUCCESS; i++) {
177 INSIST(result == ISC_R_SUCCESS);
178 dns_rdata_init(&x[i].rdata);
179 dns_rdataset_current(rdataset, &x[i].rdata);
180 INSIST(x[i].rdata.data != &removed);
181 #if DNS_RDATASET_FIXED
182 x[i].order = i;
183 #endif /* if DNS_RDATASET_FIXED */
184 result = dns_rdataset_next(rdataset);
185 }
186 if (i != nalloc || result != ISC_R_NOMORE) {
187 /*
188 * Somehow we iterated over fewer rdatas than
189 * dns_rdataset_count() said there were or there
190 * were more items than dns_rdataset_count said
191 * there were.
192 */
193 result = ISC_R_FAILURE;
194 goto free_rdatas;
195 }
196
197 /*
198 * Put into DNSSEC order.
199 */
200 if (nalloc > 1U) {
201 qsort(x, nalloc, sizeof(struct xrdata), compare_rdata);
202 }
203
204 /*
205 * Remove duplicates and compute the total storage required.
206 *
207 * If an rdata is not a duplicate, accumulate the storage size
208 * required for the rdata. We do not store the class, type, etc,
209 * just the rdata, so our overhead is 2 bytes for the number of
210 * records, and 8 for each rdata, (length(2), offset(4) and order(2))
211 * and then the rdata itself.
212 */
213 for (i = 1; i < nalloc; i++) {
214 if (compare_rdata(&x[i - 1].rdata, &x[i].rdata) == 0) {
215 x[i - 1].rdata.data = &removed;
216 #if DNS_RDATASET_FIXED
217 /*
218 * Preserve the least order so A, B, A -> A, B
219 * after duplicate removal.
220 */
221 if (x[i - 1].order < x[i].order) {
222 x[i].order = x[i - 1].order;
223 }
224 #endif /* if DNS_RDATASET_FIXED */
225 nitems--;
226 } else {
227 #if DNS_RDATASET_FIXED
228 buflen += (8 + x[i - 1].rdata.length);
229 #else /* if DNS_RDATASET_FIXED */
230 buflen += (2 + x[i - 1].rdata.length);
231 #endif /* if DNS_RDATASET_FIXED */
232 /*
233 * Provide space to store the per RR meta data.
234 */
235 if (rdataset->type == dns_rdatatype_rrsig) {
236 buflen++;
237 }
238 }
239 }
240
241 /*
242 * Don't forget the last item!
243 */
244 #if DNS_RDATASET_FIXED
245 buflen += (8 + x[i - 1].rdata.length);
246 #else /* if DNS_RDATASET_FIXED */
247 buflen += (2 + x[i - 1].rdata.length);
248 #endif /* if DNS_RDATASET_FIXED */
249 /*
250 * Provide space to store the per RR meta data.
251 */
252 if (rdataset->type == dns_rdatatype_rrsig) {
253 buflen++;
254 }
255
256 /*
257 * Ensure that singleton types are actually singletons.
258 */
259 if (nitems > 1 && dns_rdatatype_issingleton(rdataset->type)) {
260 /*
261 * We have a singleton type, but there's more than one
262 * RR in the rdataset.
263 */
264 result = DNS_R_SINGLETON;
265 goto free_rdatas;
266 }
267
268 /*
269 * Allocate the memory, set up a buffer, start copying in
270 * data.
271 */
272 rawbuf = isc_mem_get(mctx, buflen);
273
274 #if DNS_RDATASET_FIXED
275 /* Allocate temporary offset table. */
276 offsettable = isc_mem_get(mctx, nalloc * sizeof(unsigned int));
277 memset(offsettable, 0, nalloc * sizeof(unsigned int));
278 #endif /* if DNS_RDATASET_FIXED */
279
280 region->base = rawbuf;
281 region->length = buflen;
282
283 memset(rawbuf, 0, buflen);
284 rawbuf += reservelen;
285
286 #if DNS_RDATASET_FIXED
287 offsetbase = rawbuf;
288 #endif /* if DNS_RDATASET_FIXED */
289
290 *rawbuf++ = (nitems & 0xff00) >> 8;
291 *rawbuf++ = (nitems & 0x00ff);
292
293 #if DNS_RDATASET_FIXED
294 /* Skip load order table. Filled in later. */
295 rawbuf += nitems * 4;
296 #endif /* if DNS_RDATASET_FIXED */
297
298 for (i = 0; i < nalloc; i++) {
299 if (x[i].rdata.data == &removed) {
300 continue;
301 }
302 #if DNS_RDATASET_FIXED
303 offsettable[x[i].order] = rawbuf - offsetbase;
304 #endif /* if DNS_RDATASET_FIXED */
305 length = x[i].rdata.length;
306 if (rdataset->type == dns_rdatatype_rrsig) {
307 length++;
308 }
309 INSIST(length <= 0xffff);
310 *rawbuf++ = (length & 0xff00) >> 8;
311 *rawbuf++ = (length & 0x00ff);
312 #if DNS_RDATASET_FIXED
313 rawbuf += 2; /* filled in later */
314 #endif /* if DNS_RDATASET_FIXED */
315 /*
316 * Store the per RR meta data.
317 */
318 if (rdataset->type == dns_rdatatype_rrsig) {
319 *rawbuf++ = (x[i].rdata.flags & DNS_RDATA_OFFLINE)
320 ? DNS_RDATASLAB_OFFLINE
321 : 0;
322 }
323 memmove(rawbuf, x[i].rdata.data, x[i].rdata.length);
324 rawbuf += x[i].rdata.length;
325 }
326
327 #if DNS_RDATASET_FIXED
328 fillin_offsets(offsetbase, offsettable, nalloc);
329 isc_mem_put(mctx, offsettable, nalloc * sizeof(unsigned int));
330 #endif /* if DNS_RDATASET_FIXED */
331
332 result = ISC_R_SUCCESS;
333
334 free_rdatas:
335 isc_mem_put(mctx, x, nalloc * sizeof(struct xrdata));
336 return (result);
337 }
338
339 unsigned int
dns_rdataslab_size(unsigned char * slab,unsigned int reservelen)340 dns_rdataslab_size(unsigned char *slab, unsigned int reservelen) {
341 unsigned int count, length;
342 unsigned char *current;
343
344 REQUIRE(slab != NULL);
345
346 current = slab + reservelen;
347 count = *current++ * 256;
348 count += *current++;
349 #if DNS_RDATASET_FIXED
350 current += (4 * count);
351 #endif /* if DNS_RDATASET_FIXED */
352 while (count > 0) {
353 count--;
354 length = *current++ * 256;
355 length += *current++;
356 #if DNS_RDATASET_FIXED
357 current += length + 2;
358 #else /* if DNS_RDATASET_FIXED */
359 current += length;
360 #endif /* if DNS_RDATASET_FIXED */
361 }
362
363 return ((unsigned int)(current - slab));
364 }
365
366 unsigned int
dns_rdataslab_rdatasize(unsigned char * slab,unsigned int reservelen)367 dns_rdataslab_rdatasize(unsigned char *slab, unsigned int reservelen) {
368 unsigned int count, length, rdatalen = 0;
369 unsigned char *current;
370
371 REQUIRE(slab != NULL);
372
373 current = slab + reservelen;
374 count = *current++ * 256;
375 count += *current++;
376 #if DNS_RDATASET_FIXED
377 current += (4 * count);
378 #endif /* if DNS_RDATASET_FIXED */
379 while (count > 0) {
380 count--;
381 length = *current++ * 256;
382 length += *current++;
383 rdatalen += length;
384 #if DNS_RDATASET_FIXED
385 current += length + 2;
386 #else /* if DNS_RDATASET_FIXED */
387 current += length;
388 #endif /* if DNS_RDATASET_FIXED */
389 }
390
391 return (rdatalen);
392 }
393
394 unsigned int
dns_rdataslab_count(unsigned char * slab,unsigned int reservelen)395 dns_rdataslab_count(unsigned char *slab, unsigned int reservelen) {
396 unsigned int count;
397 unsigned char *current;
398
399 REQUIRE(slab != NULL);
400
401 current = slab + reservelen;
402 count = *current++ * 256;
403 count += *current++;
404 return (count);
405 }
406
407 /*
408 * Make the dns_rdata_t 'rdata' refer to the slab item
409 * beginning at '*current', which is part of a slab of type
410 * 'type' and class 'rdclass', and advance '*current' to
411 * point to the next item in the slab.
412 */
413 static inline void
rdata_from_slab(unsigned char ** current,dns_rdataclass_t rdclass,dns_rdatatype_t type,dns_rdata_t * rdata)414 rdata_from_slab(unsigned char **current, dns_rdataclass_t rdclass,
415 dns_rdatatype_t type, dns_rdata_t *rdata) {
416 unsigned char *tcurrent = *current;
417 isc_region_t region;
418 unsigned int length;
419 bool offline = false;
420
421 length = *tcurrent++ * 256;
422 length += *tcurrent++;
423
424 if (type == dns_rdatatype_rrsig) {
425 if ((*tcurrent & DNS_RDATASLAB_OFFLINE) != 0) {
426 offline = true;
427 }
428 length--;
429 tcurrent++;
430 }
431 region.length = length;
432 #if DNS_RDATASET_FIXED
433 tcurrent += 2;
434 #endif /* if DNS_RDATASET_FIXED */
435 region.base = tcurrent;
436 tcurrent += region.length;
437 dns_rdata_fromregion(rdata, rdclass, type, ®ion);
438 if (offline) {
439 rdata->flags |= DNS_RDATA_OFFLINE;
440 }
441 *current = tcurrent;
442 }
443
444 /*
445 * Return true iff 'slab' (slab data of type 'type' and class 'rdclass')
446 * contains an rdata identical to 'rdata'. This does case insensitive
447 * comparisons per DNSSEC.
448 */
449 static inline bool
rdata_in_slab(unsigned char * slab,unsigned int reservelen,dns_rdataclass_t rdclass,dns_rdatatype_t type,dns_rdata_t * rdata)450 rdata_in_slab(unsigned char *slab, unsigned int reservelen,
451 dns_rdataclass_t rdclass, dns_rdatatype_t type,
452 dns_rdata_t *rdata) {
453 unsigned int count, i;
454 unsigned char *current;
455 dns_rdata_t trdata = DNS_RDATA_INIT;
456 int n;
457
458 current = slab + reservelen;
459 count = *current++ * 256;
460 count += *current++;
461
462 #if DNS_RDATASET_FIXED
463 current += (4 * count);
464 #endif /* if DNS_RDATASET_FIXED */
465
466 for (i = 0; i < count; i++) {
467 rdata_from_slab(¤t, rdclass, type, &trdata);
468
469 n = dns_rdata_compare(&trdata, rdata);
470 if (n == 0) {
471 return (true);
472 }
473 if (n > 0) { /* In DNSSEC order. */
474 break;
475 }
476 dns_rdata_reset(&trdata);
477 }
478 return (false);
479 }
480
481 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)482 dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
483 unsigned int reservelen, isc_mem_t *mctx,
484 dns_rdataclass_t rdclass, dns_rdatatype_t type,
485 unsigned int flags, unsigned char **tslabp) {
486 unsigned char *ocurrent, *ostart, *ncurrent, *tstart, *tcurrent, *data;
487 unsigned int ocount, ncount, count, olength, tlength, tcount, length;
488 dns_rdata_t ordata = DNS_RDATA_INIT;
489 dns_rdata_t nrdata = DNS_RDATA_INIT;
490 bool added_something = false;
491 unsigned int oadded = 0;
492 unsigned int nadded = 0;
493 unsigned int nncount = 0;
494 #if DNS_RDATASET_FIXED
495 unsigned int oncount;
496 unsigned int norder = 0;
497 unsigned int oorder = 0;
498 unsigned char *offsetbase;
499 unsigned int *offsettable;
500 #endif /* if DNS_RDATASET_FIXED */
501
502 /*
503 * XXX Need parameter to allow "delete rdatasets in nslab" merge,
504 * or perhaps another merge routine for this purpose.
505 */
506
507 REQUIRE(tslabp != NULL && *tslabp == NULL);
508 REQUIRE(oslab != NULL && nslab != NULL);
509
510 ocurrent = oslab + reservelen;
511 ocount = *ocurrent++ * 256;
512 ocount += *ocurrent++;
513 #if DNS_RDATASET_FIXED
514 ocurrent += (4 * ocount);
515 #endif /* if DNS_RDATASET_FIXED */
516 ostart = ocurrent;
517 ncurrent = nslab + reservelen;
518 ncount = *ncurrent++ * 256;
519 ncount += *ncurrent++;
520 #if DNS_RDATASET_FIXED
521 ncurrent += (4 * ncount);
522 #endif /* if DNS_RDATASET_FIXED */
523 INSIST(ocount > 0 && ncount > 0);
524
525 #if DNS_RDATASET_FIXED
526 oncount = ncount;
527 #endif /* if DNS_RDATASET_FIXED */
528
529 /*
530 * Yes, this is inefficient!
531 */
532
533 /*
534 * Figure out the length of the old slab's data.
535 */
536 olength = 0;
537 for (count = 0; count < ocount; count++) {
538 length = *ocurrent++ * 256;
539 length += *ocurrent++;
540 #if DNS_RDATASET_FIXED
541 olength += length + 8;
542 ocurrent += length + 2;
543 #else /* if DNS_RDATASET_FIXED */
544 olength += length + 2;
545 ocurrent += length;
546 #endif /* if DNS_RDATASET_FIXED */
547 }
548
549 /*
550 * Start figuring out the target length and count.
551 */
552 tlength = reservelen + 2 + olength;
553 tcount = ocount;
554
555 /*
556 * Add in the length of rdata in the new slab that aren't in
557 * the old slab.
558 */
559 do {
560 dns_rdata_init(&nrdata);
561 rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
562 if (!rdata_in_slab(oslab, reservelen, rdclass, type, &nrdata)) {
563 /*
564 * This rdata isn't in the old slab.
565 */
566 #if DNS_RDATASET_FIXED
567 tlength += nrdata.length + 8;
568 #else /* if DNS_RDATASET_FIXED */
569 tlength += nrdata.length + 2;
570 #endif /* if DNS_RDATASET_FIXED */
571 if (type == dns_rdatatype_rrsig) {
572 tlength++;
573 }
574 tcount++;
575 nncount++;
576 added_something = true;
577 }
578 ncount--;
579 } while (ncount > 0);
580 ncount = nncount;
581
582 if (((flags & DNS_RDATASLAB_EXACT) != 0) && (tcount != ncount + ocount))
583 {
584 return (DNS_R_NOTEXACT);
585 }
586
587 if (!added_something && (flags & DNS_RDATASLAB_FORCE) == 0) {
588 return (DNS_R_UNCHANGED);
589 }
590
591 /*
592 * Ensure that singleton types are actually singletons.
593 */
594 if (tcount > 1 && dns_rdatatype_issingleton(type)) {
595 /*
596 * We have a singleton type, but there's more than one
597 * RR in the rdataset.
598 */
599 return (DNS_R_SINGLETON);
600 }
601
602 if (tcount > 0xffff) {
603 return (ISC_R_NOSPACE);
604 }
605
606 /*
607 * Copy the reserved area from the new slab.
608 */
609 tstart = isc_mem_get(mctx, tlength);
610 memmove(tstart, nslab, reservelen);
611 tcurrent = tstart + reservelen;
612 #if DNS_RDATASET_FIXED
613 offsetbase = tcurrent;
614 #endif /* if DNS_RDATASET_FIXED */
615
616 /*
617 * Write the new count.
618 */
619 *tcurrent++ = (tcount & 0xff00) >> 8;
620 *tcurrent++ = (tcount & 0x00ff);
621
622 #if DNS_RDATASET_FIXED
623 /*
624 * Skip offset table.
625 */
626 tcurrent += (tcount * 4);
627
628 offsettable = isc_mem_get(mctx,
629 (ocount + oncount) * sizeof(unsigned int));
630 memset(offsettable, 0, (ocount + oncount) * sizeof(unsigned int));
631 #endif /* if DNS_RDATASET_FIXED */
632
633 /*
634 * Merge the two slabs.
635 */
636 ocurrent = ostart;
637 INSIST(ocount != 0);
638 #if DNS_RDATASET_FIXED
639 oorder = ocurrent[2] * 256 + ocurrent[3];
640 INSIST(oorder < ocount);
641 #endif /* if DNS_RDATASET_FIXED */
642 rdata_from_slab(&ocurrent, rdclass, type, &ordata);
643
644 ncurrent = nslab + reservelen + 2;
645 #if DNS_RDATASET_FIXED
646 ncurrent += (4 * oncount);
647 #endif /* if DNS_RDATASET_FIXED */
648
649 if (ncount > 0) {
650 do {
651 dns_rdata_reset(&nrdata);
652 #if DNS_RDATASET_FIXED
653 norder = ncurrent[2] * 256 + ncurrent[3];
654
655 INSIST(norder < oncount);
656 #endif /* if DNS_RDATASET_FIXED */
657 rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
658 } while (rdata_in_slab(oslab, reservelen, rdclass, type,
659 &nrdata));
660 }
661
662 while (oadded < ocount || nadded < ncount) {
663 bool fromold;
664 if (oadded == ocount) {
665 fromold = false;
666 } else if (nadded == ncount) {
667 fromold = true;
668 } else {
669 fromold = (dns_rdata_compare(&ordata, &nrdata) < 0);
670 }
671 if (fromold) {
672 #if DNS_RDATASET_FIXED
673 offsettable[oorder] = tcurrent - offsetbase;
674 #endif /* if DNS_RDATASET_FIXED */
675 length = ordata.length;
676 data = ordata.data;
677 if (type == dns_rdatatype_rrsig) {
678 length++;
679 data--;
680 }
681 *tcurrent++ = (length & 0xff00) >> 8;
682 *tcurrent++ = (length & 0x00ff);
683 #if DNS_RDATASET_FIXED
684 tcurrent += 2; /* fill in later */
685 #endif /* if DNS_RDATASET_FIXED */
686 memmove(tcurrent, data, length);
687 tcurrent += length;
688 oadded++;
689 if (oadded < ocount) {
690 dns_rdata_reset(&ordata);
691 #if DNS_RDATASET_FIXED
692 oorder = ocurrent[2] * 256 + ocurrent[3];
693 INSIST(oorder < ocount);
694 #endif /* if DNS_RDATASET_FIXED */
695 rdata_from_slab(&ocurrent, rdclass, type,
696 &ordata);
697 }
698 } else {
699 #if DNS_RDATASET_FIXED
700 offsettable[ocount + norder] = tcurrent - offsetbase;
701 #endif /* if DNS_RDATASET_FIXED */
702 length = nrdata.length;
703 data = nrdata.data;
704 if (type == dns_rdatatype_rrsig) {
705 length++;
706 data--;
707 }
708 *tcurrent++ = (length & 0xff00) >> 8;
709 *tcurrent++ = (length & 0x00ff);
710 #if DNS_RDATASET_FIXED
711 tcurrent += 2; /* fill in later */
712 #endif /* if DNS_RDATASET_FIXED */
713 memmove(tcurrent, data, length);
714 tcurrent += length;
715 nadded++;
716 if (nadded < ncount) {
717 do {
718 dns_rdata_reset(&nrdata);
719 #if DNS_RDATASET_FIXED
720 norder = ncurrent[2] * 256 +
721 ncurrent[3];
722 INSIST(norder < oncount);
723 #endif /* if DNS_RDATASET_FIXED */
724 rdata_from_slab(&ncurrent, rdclass,
725 type, &nrdata);
726 } while (rdata_in_slab(oslab, reservelen,
727 rdclass, type, &nrdata));
728 }
729 }
730 }
731
732 #if DNS_RDATASET_FIXED
733 fillin_offsets(offsetbase, offsettable, ocount + oncount);
734
735 isc_mem_put(mctx, offsettable,
736 (ocount + oncount) * sizeof(unsigned int));
737 #endif /* if DNS_RDATASET_FIXED */
738
739 INSIST(tcurrent == tstart + tlength);
740
741 *tslabp = tstart;
742
743 return (ISC_R_SUCCESS);
744 }
745
746 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)747 dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
748 unsigned int reservelen, isc_mem_t *mctx,
749 dns_rdataclass_t rdclass, dns_rdatatype_t type,
750 unsigned int flags, unsigned char **tslabp) {
751 unsigned char *mcurrent, *sstart, *scurrent, *tstart, *tcurrent;
752 unsigned int mcount, scount, rcount, count, tlength, tcount, i;
753 dns_rdata_t srdata = DNS_RDATA_INIT;
754 dns_rdata_t mrdata = DNS_RDATA_INIT;
755 #if DNS_RDATASET_FIXED
756 unsigned char *offsetbase;
757 unsigned int *offsettable;
758 unsigned int order;
759 #endif /* if DNS_RDATASET_FIXED */
760
761 REQUIRE(tslabp != NULL && *tslabp == NULL);
762 REQUIRE(mslab != NULL && sslab != NULL);
763
764 mcurrent = mslab + reservelen;
765 mcount = *mcurrent++ * 256;
766 mcount += *mcurrent++;
767 scurrent = sslab + reservelen;
768 scount = *scurrent++ * 256;
769 scount += *scurrent++;
770 INSIST(mcount > 0 && scount > 0);
771
772 /*
773 * Yes, this is inefficient!
774 */
775
776 /*
777 * Start figuring out the target length and count.
778 */
779 tlength = reservelen + 2;
780 tcount = 0;
781 rcount = 0;
782
783 #if DNS_RDATASET_FIXED
784 mcurrent += 4 * mcount;
785 scurrent += 4 * scount;
786 #endif /* if DNS_RDATASET_FIXED */
787 sstart = scurrent;
788
789 /*
790 * Add in the length of rdata in the mslab that aren't in
791 * the sslab.
792 */
793 for (i = 0; i < mcount; i++) {
794 unsigned char *mrdatabegin = mcurrent;
795 rdata_from_slab(&mcurrent, rdclass, type, &mrdata);
796 scurrent = sstart;
797 for (count = 0; count < scount; count++) {
798 dns_rdata_reset(&srdata);
799 rdata_from_slab(&scurrent, rdclass, type, &srdata);
800 if (dns_rdata_compare(&mrdata, &srdata) == 0) {
801 break;
802 }
803 }
804 if (count == scount) {
805 /*
806 * This rdata isn't in the sslab, and thus isn't
807 * being subtracted.
808 */
809 tlength += (unsigned int)(mcurrent - mrdatabegin);
810 tcount++;
811 } else {
812 rcount++;
813 }
814 dns_rdata_reset(&mrdata);
815 }
816
817 #if DNS_RDATASET_FIXED
818 tlength += (4 * tcount);
819 #endif /* if DNS_RDATASET_FIXED */
820
821 /*
822 * Check that all the records originally existed. The numeric
823 * check only works as rdataslabs do not contain duplicates.
824 */
825 if (((flags & DNS_RDATASLAB_EXACT) != 0) && (rcount != scount)) {
826 return (DNS_R_NOTEXACT);
827 }
828
829 /*
830 * Don't continue if the new rdataslab would be empty.
831 */
832 if (tcount == 0) {
833 return (DNS_R_NXRRSET);
834 }
835
836 /*
837 * If nothing is going to change, we can stop.
838 */
839 if (rcount == 0) {
840 return (DNS_R_UNCHANGED);
841 }
842
843 /*
844 * Copy the reserved area from the mslab.
845 */
846 tstart = isc_mem_get(mctx, tlength);
847 memmove(tstart, mslab, reservelen);
848 tcurrent = tstart + reservelen;
849 #if DNS_RDATASET_FIXED
850 offsetbase = tcurrent;
851
852 offsettable = isc_mem_get(mctx, mcount * sizeof(unsigned int));
853 memset(offsettable, 0, mcount * sizeof(unsigned int));
854 #endif /* if DNS_RDATASET_FIXED */
855
856 /*
857 * Write the new count.
858 */
859 *tcurrent++ = (tcount & 0xff00) >> 8;
860 *tcurrent++ = (tcount & 0x00ff);
861
862 #if DNS_RDATASET_FIXED
863 tcurrent += (4 * tcount);
864 #endif /* if DNS_RDATASET_FIXED */
865
866 /*
867 * Copy the parts of mslab not in sslab.
868 */
869 mcurrent = mslab + reservelen;
870 mcount = *mcurrent++ * 256;
871 mcount += *mcurrent++;
872 #if DNS_RDATASET_FIXED
873 mcurrent += (4 * mcount);
874 #endif /* if DNS_RDATASET_FIXED */
875 for (i = 0; i < mcount; i++) {
876 unsigned char *mrdatabegin = mcurrent;
877 #if DNS_RDATASET_FIXED
878 order = mcurrent[2] * 256 + mcurrent[3];
879 INSIST(order < mcount);
880 #endif /* if DNS_RDATASET_FIXED */
881 rdata_from_slab(&mcurrent, rdclass, type, &mrdata);
882 scurrent = sstart;
883 for (count = 0; count < scount; count++) {
884 dns_rdata_reset(&srdata);
885 rdata_from_slab(&scurrent, rdclass, type, &srdata);
886 if (dns_rdata_compare(&mrdata, &srdata) == 0) {
887 break;
888 }
889 }
890 if (count == scount) {
891 /*
892 * This rdata isn't in the sslab, and thus should be
893 * copied to the tslab.
894 */
895 unsigned int length;
896 length = (unsigned int)(mcurrent - mrdatabegin);
897 #if DNS_RDATASET_FIXED
898 offsettable[order] = tcurrent - offsetbase;
899 #endif /* if DNS_RDATASET_FIXED */
900 memmove(tcurrent, mrdatabegin, length);
901 tcurrent += length;
902 }
903 dns_rdata_reset(&mrdata);
904 }
905
906 #if DNS_RDATASET_FIXED
907 fillin_offsets(offsetbase, offsettable, mcount);
908
909 isc_mem_put(mctx, offsettable, mcount * sizeof(unsigned int));
910 #endif /* if DNS_RDATASET_FIXED */
911
912 INSIST(tcurrent == tstart + tlength);
913
914 *tslabp = tstart;
915
916 return (ISC_R_SUCCESS);
917 }
918
919 bool
dns_rdataslab_equal(unsigned char * slab1,unsigned char * slab2,unsigned int reservelen)920 dns_rdataslab_equal(unsigned char *slab1, unsigned char *slab2,
921 unsigned int reservelen) {
922 unsigned char *current1, *current2;
923 unsigned int count1, count2;
924 unsigned int length1, length2;
925
926 current1 = slab1 + reservelen;
927 count1 = *current1++ * 256;
928 count1 += *current1++;
929
930 current2 = slab2 + reservelen;
931 count2 = *current2++ * 256;
932 count2 += *current2++;
933
934 if (count1 != count2) {
935 return (false);
936 }
937
938 #if DNS_RDATASET_FIXED
939 current1 += (4 * count1);
940 current2 += (4 * count2);
941 #endif /* if DNS_RDATASET_FIXED */
942
943 while (count1 > 0) {
944 length1 = *current1++ * 256;
945 length1 += *current1++;
946
947 length2 = *current2++ * 256;
948 length2 += *current2++;
949
950 #if DNS_RDATASET_FIXED
951 current1 += 2;
952 current2 += 2;
953 #endif /* if DNS_RDATASET_FIXED */
954
955 if (length1 != length2 ||
956 memcmp(current1, current2, length1) != 0) {
957 return (false);
958 }
959
960 current1 += length1;
961 current2 += length1;
962
963 count1--;
964 }
965 return (true);
966 }
967
968 bool
dns_rdataslab_equalx(unsigned char * slab1,unsigned char * slab2,unsigned int reservelen,dns_rdataclass_t rdclass,dns_rdatatype_t type)969 dns_rdataslab_equalx(unsigned char *slab1, unsigned char *slab2,
970 unsigned int reservelen, dns_rdataclass_t rdclass,
971 dns_rdatatype_t type) {
972 unsigned char *current1, *current2;
973 unsigned int count1, count2;
974 dns_rdata_t rdata1 = DNS_RDATA_INIT;
975 dns_rdata_t rdata2 = DNS_RDATA_INIT;
976
977 current1 = slab1 + reservelen;
978 count1 = *current1++ * 256;
979 count1 += *current1++;
980
981 current2 = slab2 + reservelen;
982 count2 = *current2++ * 256;
983 count2 += *current2++;
984
985 if (count1 != count2) {
986 return (false);
987 }
988
989 #if DNS_RDATASET_FIXED
990 current1 += (4 * count1);
991 current2 += (4 * count2);
992 #endif /* if DNS_RDATASET_FIXED */
993
994 while (count1-- > 0) {
995 rdata_from_slab(¤t1, rdclass, type, &rdata1);
996 rdata_from_slab(¤t2, rdclass, type, &rdata2);
997 if (dns_rdata_compare(&rdata1, &rdata2) != 0) {
998 return (false);
999 }
1000 dns_rdata_reset(&rdata1);
1001 dns_rdata_reset(&rdata2);
1002 }
1003 return (true);
1004 }
1005