2 * Copyright (C) 2004, 2005, 2007, 2010 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1999-2003 Internet Software Consortium.
5 * Permission to use, copy, modify, and/or distribute this software for any
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11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
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15 * PERFORMANCE OF THIS SOFTWARE.
18 /* $Id: ncache.c,v 1.41.288.2 2010/02/25 10:56:01 tbox Exp $ */
24 #include <isc/buffer.h>
28 #include <dns/message.h>
29 #include <dns/ncache.h>
30 #include <dns/rdata.h>
31 #include <dns/rdatalist.h>
32 #include <dns/rdataset.h>
35 * The format of an ncache rdata is a sequence of one or more records of
36 * the following format:
41 * rdata length These two occur 'rdata count'
46 static inline isc_result_t
47 copy_rdataset(dns_rdataset_t *rdataset, isc_buffer_t *buffer) {
51 dns_rdata_t rdata = DNS_RDATA_INIT;
54 * Copy the rdataset count to the buffer.
56 isc_buffer_availableregion(buffer, &ar);
58 return (ISC_R_NOSPACE);
59 count = dns_rdataset_count(rdataset);
60 INSIST(count <= 65535);
61 isc_buffer_putuint16(buffer, (isc_uint16_t)count);
63 result = dns_rdataset_first(rdataset);
64 while (result == ISC_R_SUCCESS) {
65 dns_rdataset_current(rdataset, &rdata);
66 dns_rdata_toregion(&rdata, &r);
67 INSIST(r.length <= 65535);
68 isc_buffer_availableregion(buffer, &ar);
70 return (ISC_R_NOSPACE);
72 * Copy the rdata length to the buffer.
74 isc_buffer_putuint16(buffer, (isc_uint16_t)r.length);
76 * Copy the rdata to the buffer.
78 result = isc_buffer_copyregion(buffer, &r);
79 if (result != ISC_R_SUCCESS)
81 dns_rdata_reset(&rdata);
82 result = dns_rdataset_next(rdataset);
84 if (result != ISC_R_NOMORE)
87 return (ISC_R_SUCCESS);
91 dns_ncache_add(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
92 dns_rdatatype_t covers, isc_stdtime_t now, dns_ttl_t maxttl,
93 dns_rdataset_t *addedrdataset)
98 dns_rdataset_t *rdataset;
103 dns_rdata_t rdata = DNS_RDATA_INIT;
104 dns_rdataset_t ncrdataset;
105 dns_rdatalist_t ncrdatalist;
106 unsigned char data[4096];
109 * Convert the authority data from 'message' into a negative cache
110 * rdataset, and store it in 'cache' at 'node'.
113 REQUIRE(message != NULL);
116 * We assume that all data in the authority section has been
117 * validated by the caller.
121 * First, build an ncache rdata in buffer.
125 isc_buffer_init(&buffer, data, sizeof(data));
126 if (message->counts[DNS_SECTION_AUTHORITY])
127 result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
129 result = ISC_R_NOMORE;
130 while (result == ISC_R_SUCCESS) {
132 dns_message_currentname(message, DNS_SECTION_AUTHORITY,
134 if ((name->attributes & DNS_NAMEATTR_NCACHE) != 0) {
135 for (rdataset = ISC_LIST_HEAD(name->list);
137 rdataset = ISC_LIST_NEXT(rdataset, link)) {
138 if ((rdataset->attributes &
139 DNS_RDATASETATTR_NCACHE) == 0)
141 type = rdataset->type;
142 if (type == dns_rdatatype_rrsig)
143 type = rdataset->covers;
144 if (type == dns_rdatatype_soa ||
145 type == dns_rdatatype_nsec) {
146 if (ttl > rdataset->ttl)
148 if (trust > rdataset->trust)
149 trust = rdataset->trust;
151 * Copy the owner name to the buffer.
153 dns_name_toregion(name, &r);
154 result = isc_buffer_copyregion(&buffer,
156 if (result != ISC_R_SUCCESS)
159 * Copy the type to the buffer.
161 isc_buffer_availableregion(&buffer,
164 return (ISC_R_NOSPACE);
165 isc_buffer_putuint16(&buffer,
168 * Copy the rdataset into the buffer.
170 result = copy_rdataset(rdataset,
172 if (result != ISC_R_SUCCESS)
177 result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
179 if (result != ISC_R_NOMORE)
182 if (trust == 0xffff) {
184 * We didn't find any authority data from which to create a
185 * negative cache rdataset. In particular, we have no SOA.
187 * We trust that the caller wants negative caching, so this
188 * means we have a "type 3 nxdomain" or "type 3 nodata"
189 * response (see RFC2308 for details).
191 * We will now build a suitable negative cache rdataset that
192 * will cause zero bytes to be emitted when converted to
197 * The ownername must exist, but it doesn't matter what value
198 * it has. We use the root name.
200 dns_name_toregion(dns_rootname, &r);
201 result = isc_buffer_copyregion(&buffer, &r);
202 if (result != ISC_R_SUCCESS)
205 * Copy the type and a zero rdata count to the buffer.
207 isc_buffer_availableregion(&buffer, &r);
209 return (ISC_R_NOSPACE);
210 isc_buffer_putuint16(&buffer, 0);
211 isc_buffer_putuint16(&buffer, 0);
213 * RFC2308, section 5, says that negative answers without
214 * SOAs should not be cached.
220 if ((message->flags & DNS_MESSAGEFLAG_AA) != 0 &&
221 message->counts[DNS_SECTION_ANSWER] == 0) {
223 * The response has aa set and we haven't followed
224 * any CNAME or DNAME chains.
226 trust = dns_trust_authauthority;
228 trust = dns_trust_additional;
232 * Now add it to the cache.
234 INSIST(trust != 0xffff);
235 isc_buffer_usedregion(&buffer, &r);
237 rdata.length = r.length;
238 rdata.rdclass = dns_db_class(cache);
242 ncrdatalist.rdclass = rdata.rdclass;
243 ncrdatalist.type = 0;
244 ncrdatalist.covers = covers;
245 ncrdatalist.ttl = ttl;
246 ISC_LIST_INIT(ncrdatalist.rdata);
247 ISC_LINK_INIT(&ncrdatalist, link);
249 ISC_LIST_APPEND(ncrdatalist.rdata, &rdata, link);
251 dns_rdataset_init(&ncrdataset);
252 RUNTIME_CHECK(dns_rdatalist_tordataset(&ncrdatalist, &ncrdataset)
254 ncrdataset.trust = trust;
255 if (message->rcode == dns_rcode_nxdomain)
256 ncrdataset.attributes |= DNS_RDATASETATTR_NXDOMAIN;
258 return (dns_db_addrdataset(cache, node, NULL, now, &ncrdataset,
263 dns_ncache_towire(dns_rdataset_t *rdataset, dns_compress_t *cctx,
264 isc_buffer_t *target, unsigned int options,
265 unsigned int *countp)
267 dns_rdata_t rdata = DNS_RDATA_INIT;
269 isc_region_t remaining, tavailable;
270 isc_buffer_t source, savedbuffer, rdlen;
272 dns_rdatatype_t type;
273 unsigned int i, rcount, count;
276 * Convert the negative caching rdataset 'rdataset' to wire format,
277 * compressing names as specified in 'cctx', and storing the result in
281 REQUIRE(rdataset != NULL);
282 REQUIRE(rdataset->type == 0);
284 result = dns_rdataset_first(rdataset);
285 if (result != ISC_R_SUCCESS)
287 dns_rdataset_current(rdataset, &rdata);
288 INSIST(dns_rdataset_next(rdataset) == ISC_R_NOMORE);
289 isc_buffer_init(&source, rdata.data, rdata.length);
290 isc_buffer_add(&source, rdata.length);
292 savedbuffer = *target;
296 dns_name_init(&name, NULL);
297 isc_buffer_remainingregion(&source, &remaining);
298 dns_name_fromregion(&name, &remaining);
299 INSIST(remaining.length >= name.length);
300 isc_buffer_forward(&source, name.length);
301 remaining.length -= name.length;
303 INSIST(remaining.length >= 4);
304 type = isc_buffer_getuint16(&source);
305 rcount = isc_buffer_getuint16(&source);
307 for (i = 0; i < rcount; i++) {
309 * Get the length of this rdata and set up an
310 * rdata structure for it.
312 isc_buffer_remainingregion(&source, &remaining);
313 INSIST(remaining.length >= 2);
314 dns_rdata_reset(&rdata);
315 rdata.length = isc_buffer_getuint16(&source);
316 isc_buffer_remainingregion(&source, &remaining);
317 rdata.data = remaining.base;
319 rdata.rdclass = rdataset->rdclass;
320 INSIST(remaining.length >= rdata.length);
321 isc_buffer_forward(&source, rdata.length);
323 if ((options & DNS_NCACHETOWIRE_OMITDNSSEC) != 0 &&
324 dns_rdatatype_isdnssec(type))
330 dns_compress_setmethods(cctx, DNS_COMPRESS_GLOBAL14);
331 result = dns_name_towire(&name, cctx, target);
332 if (result != ISC_R_SUCCESS)
336 * See if we have space for type, class, ttl, and
337 * rdata length. Write the type, class, and ttl.
339 isc_buffer_availableregion(target, &tavailable);
340 if (tavailable.length < 10) {
341 result = ISC_R_NOSPACE;
344 isc_buffer_putuint16(target, type);
345 isc_buffer_putuint16(target, rdataset->rdclass);
346 isc_buffer_putuint32(target, rdataset->ttl);
349 * Save space for rdata length.
352 isc_buffer_add(target, 2);
357 result = dns_rdata_towire(&rdata, cctx, target);
358 if (result != ISC_R_SUCCESS)
362 * Set the rdata length field to the compressed
365 INSIST((target->used >= rdlen.used + 2) &&
366 (target->used - rdlen.used - 2 < 65536));
367 isc_buffer_putuint16(&rdlen,
368 (isc_uint16_t)(target->used -
373 isc_buffer_remainingregion(&source, &remaining);
374 } while (remaining.length > 0);
378 return (ISC_R_SUCCESS);
381 INSIST(savedbuffer.used < 65536);
382 dns_compress_rollback(cctx, (isc_uint16_t)savedbuffer.used);
384 *target = savedbuffer;
390 rdataset_disassociate(dns_rdataset_t *rdataset) {
395 rdataset_first(dns_rdataset_t *rdataset) {
396 unsigned char *raw = rdataset->private3;
399 count = raw[0] * 256 + raw[1];
401 rdataset->private5 = NULL;
402 return (ISC_R_NOMORE);
406 * The privateuint4 field is the number of rdata beyond the cursor
407 * position, so we decrement the total count by one before storing
411 rdataset->privateuint4 = count;
412 rdataset->private5 = raw;
414 return (ISC_R_SUCCESS);
418 rdataset_next(dns_rdataset_t *rdataset) {
423 count = rdataset->privateuint4;
425 return (ISC_R_NOMORE);
427 rdataset->privateuint4 = count;
428 raw = rdataset->private5;
429 length = raw[0] * 256 + raw[1];
431 rdataset->private5 = raw;
433 return (ISC_R_SUCCESS);
437 rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
438 unsigned char *raw = rdataset->private5;
441 REQUIRE(raw != NULL);
443 r.length = raw[0] * 256 + raw[1];
446 dns_rdata_fromregion(rdata, rdataset->rdclass, rdataset->type, &r);
450 rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
454 * Reset iterator state.
456 target->privateuint4 = 0;
457 target->private5 = NULL;
461 rdataset_count(dns_rdataset_t *rdataset) {
462 unsigned char *raw = rdataset->private3;
465 count = raw[0] * 256 + raw[1];
470 static dns_rdatasetmethods_t rdataset_methods = {
471 rdataset_disassociate,
487 dns_ncache_getrdataset(dns_rdataset_t *ncacherdataset, dns_name_t *name,
488 dns_rdatatype_t type, dns_rdataset_t *rdataset)
491 dns_rdata_t rdata = DNS_RDATA_INIT;
492 isc_region_t remaining;
495 dns_rdatatype_t ttype;
496 unsigned int i, rcount;
499 REQUIRE(ncacherdataset != NULL);
500 REQUIRE(ncacherdataset->type == 0);
501 REQUIRE(name != NULL);
502 REQUIRE(!dns_rdataset_isassociated(rdataset));
503 REQUIRE(type != dns_rdatatype_rrsig);
505 result = dns_rdataset_first(ncacherdataset);
506 if (result != ISC_R_SUCCESS)
508 dns_rdataset_current(ncacherdataset, &rdata);
509 INSIST(dns_rdataset_next(ncacherdataset) == ISC_R_NOMORE);
510 isc_buffer_init(&source, rdata.data, rdata.length);
511 isc_buffer_add(&source, rdata.length);
514 dns_name_init(&tname, NULL);
515 isc_buffer_remainingregion(&source, &remaining);
516 dns_name_fromregion(&tname, &remaining);
517 INSIST(remaining.length >= tname.length);
518 isc_buffer_forward(&source, tname.length);
519 remaining.length -= tname.length;
521 INSIST(remaining.length >= 4);
522 ttype = isc_buffer_getuint16(&source);
524 if (ttype == type && dns_name_equal(&tname, name)) {
525 isc_buffer_remainingregion(&source, &remaining);
529 rcount = isc_buffer_getuint16(&source);
530 for (i = 0; i < rcount; i++) {
531 isc_buffer_remainingregion(&source, &remaining);
532 INSIST(remaining.length >= 2);
533 length = isc_buffer_getuint16(&source);
534 isc_buffer_remainingregion(&source, &remaining);
535 INSIST(remaining.length >= length);
536 isc_buffer_forward(&source, length);
538 isc_buffer_remainingregion(&source, &remaining);
539 } while (remaining.length > 0);
541 if (remaining.length == 0)
542 return (ISC_R_NOTFOUND);
544 rdataset->methods = &rdataset_methods;
545 rdataset->rdclass = ncacherdataset->rdclass;
546 rdataset->type = type;
547 rdataset->covers = 0;
548 rdataset->ttl = ncacherdataset->ttl;
549 rdataset->trust = ncacherdataset->trust;
550 rdataset->private1 = NULL;
551 rdataset->private2 = NULL;
553 rdataset->private3 = remaining.base;
556 * Reset iterator state.
558 rdataset->privateuint4 = 0;
559 rdataset->private5 = NULL;
560 return (ISC_R_SUCCESS);