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